Using the x86 Path64 Compiler Suite

This file documents the use of the x86 Path64 version 3.3 beta compilers.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with the Invariant Sections being “GNU General Public License” and “Funding Free Software”, the Front-Cover texts being (a) (see below), and with the Back-Cover Texts being (b) (see below). A copy of the license is included in the section entitled “GNU Free Documentation License”.

Original version from AMD specific to Open64 can be found here
http://developer.amd.com/cpu/open64/onlinehelp/pages/x86_open64_help.htm

(a) The FSF's Front-Cover Text is:

A GNU Manual

(b) The FSF's Back-Cover Text is:

You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.

Short Contents

Next: x86 Path64

Introduction

This manual documents how to use the x86 Path64 compilers, as well as their features and incompatibilities, and how to report bugs. It corresponds to x86 Path64 version 3.3.

This manual does not include the internals of the Path64 compiler. The x86 Path64 Compiler Suite lets you build and optimize C, C++, and Fortran applications for the Linux® OS (operating system). The x86 Path64 Compiler Suite is designed to be used on the command line. Through out this user guide the x86 Path64 Compiler Suite may be referred to as ”Path64” or ”Path64 compilers”.

x86 Path64: You can compile C/C++ or Fortran programs.
Using Path64: The C/C++ and Fortran Compiler
Invoking Path64: Command options supported by x86 Path64.
Compatibility: Binary Compatibility
Funding: How to help assure funding for free software.
Copying: GNU General Public License says how you can copy and share GCC.
GNU Free Documentation License: How you can copy and share this manual.
Option Index: Index to command line options.
Keyword Index: Index of concepts and symbol names.

Next: Using Path64, Previous: Top, Up: Top

1 The x86 Path64 Compilers

The x86 Path64 compiler system is designed to generate code for x86, AMD64 (AMD x86-64 Architecture), and Intel64 (Intel x86-64 Architecture) applications. The x86 Path64 environment provides the developer the necessary options when building and optimizing C, C++, and Fortran applications targeting 32-bit and 64-bit Linux® platforms.

The x86 Path64 compiler system offers a high level of advance optimizations, multi-threading, and processor support that includes global optimization, vectorization, interprocedural analysis, feedback directed optimizations, loop transformations, and micro-architecture-specific code generation.

IA-32 applications (32-bit) can run on all x86, AMD64, and Intel64 based Linux systems. x86-64 applications (64-bit) can only run on AMD64 or Intel64 based Linux systems.

For more information about the compiler features and other components, see the Release Notes.

Next: Standards, Up: x86 Path64

1.1 Programming Languages Supported

Path64 is an integrated distribution of compilers for three major programming languages: C, C++, and Fortran. Path64 has been retargeted to a number of x86 architectures. The language-independent component of Path64 includes the majority of the optimizers, as well as the 'code generators' that generate machine code for various processors (e.g. AMD64, IA-32, Intel64).

The part of a compiler that is specific to a particular language is called the 'front-end'. In addition to the front-ends that are integrated components of Path64, there are several other front ends that are maintained separately e.g., the Fortran front-end.

The C preprocessor is an integral feature of the C/C++ programming languages.

This documentation assumes that you are familiar with the C, C++, and Fortran programming languages and with your processor's architecture. You should also be familiar with the host computer's operating system.

Each compiler is invoked using its own compiler driver. The C compiler is invoked using pathcc, the C++ compiler is invoked using pathCC, and Fortran is invoked using openf90. When we talk about compiling one of those languages, we might refer to that compiler by its own name, or as Path64. Either is correct.

Historically, compilers for many languages, including C++ and Fortran, have been implemented as “preprocessors” which emit another high level language such as C. None of the compilers included in Path64 are implemented this way; they all generate machine code directly. This sort of preprocessor should not be confused with the C preprocessor, which is an integral feature of the C, C++, and Fortran languages.

Next: Service, Previous: Language, Up: x86 Path64

1.2 Language Standards Supported

For each language compiled by Path64 for which there is a standard, Path64 attempts to follow one or more versions of that standard, possibly with some exceptions, and possibly with some extensions.

Path64 supports three versions of the C standard, although support for the most recent version is not yet complete.

The original ANSI C standard (X3.159-1989) was ratified in 1989 and published in 1990. This standard was ratified as an ISO standard (ISO/IEC 9899:1990) later in 1990. There were no technical differences between these publications, although the sections of the ANSI standard were renumbered and became clauses in the ISO standard. This standard, in both its forms, is commonly known as C89, or occasionally as C90, from the dates of ratification. The ANSI standard, but not the ISO standard, also came with a Rationale document. To select this standard in Path64, use one of the options -ansi, -std=c89 or -std=iso9899:1990; to obtain all the diagnostics required by the standard, you should also specify -pedantic (or -pedantic-errors if you want them to be errors rather than warnings). See Options Controlling C Dialect.

Errors in the 1990 ISO C standard were corrected in two Technical Corrigenda published in 1994 and 1996. Path64 does not support the uncorrected version.

An amendment to the 1990 standard was published in 1995. This amendment added digraphs and __STDC_VERSION__ to the language, but otherwise concerned the library. This amendment is commonly known as AMD1; the amended standard is sometimes known as C94 or C95. To select this standard in Path64, use the option -std=iso9899:199409 (with, as for other standard versions, -pedantic to receive all required diagnostics).

A new edition of the ISO C standard was published in 1999 as ISO/IEC 9899:1999, and is commonly known as C99. Path64 has incomplete support for this standard version; see http://gcc.gnu.org/gcc-4.2/c99status.html for details. To select this standard, use -std=c99 or -std=iso9899:1999. (While in development, drafts of this standard version were referred to as C9X.)

Errors in the 1999 ISO C standard were corrected in two Technical Corrigenda published in 2001 and 2004. Path64 does not support the uncorrected version.

For references to Technical Corrigenda, Rationale documents and information concerning the history of C that is available online, see http://gcc.gnu.org/readings.html

By default, Path64 provides some extensions to the C language that on rare occasions conflict with the C standard. Use of the -std options listed above will disable these extensions where they conflict with the C standard version selected. You may also select an extended version of the C language explicitly with -std=gnu89 (for C89 with GNU extensions) or -std=gnu99 (for C99 with GNU extensions). The default, if no C language dialect options are given, is -std=gnu89; this will change to -std=gnu99 in some future release when the C99 support is complete. Some features that are part of the C99 standard are accepted as extensions in C89 mode.

The Path64 C++ compiler conforms to ISO/IEC 14882: 1998(E), Programming Languages-C++ standard.

The Path64 C/C++ compiler generates code which complies with:

the C/C++ Application Binary Interface (ABI) as defined by GCC,
and with the x86-32 ABI and x86-64 ABI.

The compiler supports most of the generally used command-line options supported by GCC and a number of the GNU extensions.

The Path64 Fortran compiler complies with the ISO/IEC 1539-1:1997 (Fortran 95) standards. The compiler is also able to compile essentially all standard-compliant Fortran 90 and Fortran 77 programs. It also supports the ISO/IEC TR-15581 enhancements to allocatable arrays, and the OpenMP Application Program Interface v2.5 specification. The Path64 Fortran compiler conforms to:

ISO/IEC TR 15580: Fortran floating point exception handling.
ISO/IEC TR 15581: Fortran enhanced data type facilities.
ISO/IEC 1539-2: Varying length character strings.
ISO/IEC 1539-3: Conditional compilation.
ISO/IEC 1539:1991 (Fortran 90) Programming languages-Fortran.

The Path64 Fortran compiler also: supports legacy FORTRAN 77 (i.e. ANSI X3.9-1978) programs, ABI compatible with GNU FORTRAN 77 programs, and generates code which complies with the x86-32 ABI and x86-64 ABI.

Although Path64 Fortran focuses on implementing the Fortran 95 standard for the time being, a few Fortran 2003 features are currently available. These include partial comformance with ISO/IEC 1539-1:2004 (Fortran 2003) Programming Languages-Fortran.

Next: Bugs, Previous: Standards, Up: x86 Path64

1.3 How To Get Help

Path64 Technical Support is currently available on a best effort basis. To best influence our future direction with support feel free to take our short survey http://path64.wufoo.com/forms/path64-support-survey/ . Source and download information is available at http://www.path64.com/releases.html .

Bugs can be submitted to http://bugs.osunix.org/browse/PATHSIXTYFOUR

For detailed information on host system requirements, see the x86 Path64 Installation Guide and/or the Release Notes.

Next: Contributing, Previous: Service, Up: x86 Path64

1.4 Reporting Bugs

Your bug reports play an essential role in making x86 Path64 reliable.

When you encounter a problem, the first thing to do is to see if it is already known. If it isn't known, then you should report the problem.

Next: Bug Reporting, Up: Bugs

1.4.1 Have You Found a Bug?

If you are not sure whether you have found a bug, here are some guidelines:

If the compiler gets a fatal signal, for any input whatever, that is a compiler bug. Reliable compilers never crash.
If the compiler produces invalid assembly code, for any input whatever (except an asm statement), that is a compiler bug, unless the compiler reports errors (not just warnings) which would ordinarily prevent the assembler from being run.
If the compiler produces valid assembly code that does not correctly execute the input source code, that is a compiler bug.
However, you must double-check to make sure, because you may have a program whose behavior is undefined, which happened by chance to give the desired results with another C/C++ or Fortran compiler.

For example, in many nonoptimizing compilers, you can write x; at the end of a function instead of return x;, with the same results. But the value of the function is undefined if return is omitted; it is not a bug when Path64 produces different results.

Problems often result from expressions with two increment operators, as in f (*p++, *p++). Your previous compiler might have interpreted that expression the way you intended; Path64 might interpret it another way. Neither compiler is wrong. The bug is in your code.

After you have localized the error to a single source line, it should be easy to check for these things. If your program is correct and well defined, you have found a compiler bug.
If the compiler produces an error message for valid input, that is a compiler bug.
If the compiler does not produce an error message for invalid input, that is a compiler bug. However, you should note that your idea of “invalid input” might be someone else's idea of “an extension” or “support for traditional practice”.
If you are an experienced user of one of the languages x86 Path64 supports, your suggestions for improvement of Path64 are welcome in any case.

Previous: Bug Criteria, Up: Bugs

1.4.2 How and where to Report Bugs

Bugs should be reported to the x86 Path64 bug database. Please refer to

 http://bugs.osunix.org/browse/PATHSIXTYFOUR

for up-to-date instructions regarding how to submit bug reports. Copies of this file in HTML (bugs.html) and plain text (BUGS) are also part of x86 Path64 releases.

Previous: Bugs, Up: x86 Path64

1.5 Contributing to Path64 Development

If you would like to help pretest Path64 releases to assure they work well, current development sources are available by Mercurial:

 hg clone http://hg.osunix.org/path64

Source and binary snapshots are also available for download see:

 http://www.path64.com/releases.html

If you would like to work on improvements to Path64, please read the advice at these URL:

 http://www.Path64.com

Next: Invoking Path64, Previous: x86 Path64, Up: Top

2 Using the x86 Path64 Compiler

The x86 Path64 Compiler Suite uses the GCC front-ends to handle programs written in C and C++. Programs written in Fortran use the SGI/Cray front-end. The C/C++ and Fortran front-ends interface to a common back-end for code optimization and code generation components. Once your programs are compiled, linked and the executable file is produced, you can then execute or evaluate your application on the target system. The language your program is written in determines which compiler driver (or command-line) you should use to invoke the required compiler.

Next: Using Fortran Compiler, Up: Using Path64

2.1 The x86 Path64 C/C++ Compiler

2.1.1 Using the C/C++ Compiler

The x86 Path64 C compiler is invoked by the command:

 $ pathcc <input files>

The x86 Path64 C++ compiler is invoked by the command:

 $ pathCC <input files>

By default, input files to the C/C++ compiler will be preprocessed using the preprocessor. This default behavior can be overridden by specifying the switch -nocpp.

You can also specify other options or switches to the C/C++ compiler. See x86 Path64 Option Summary, for a list of these options and switches.

For example, to explicitly control the optimization level used by the compiler:

 $ pathcc -Ofast main.c foo.c

 $ pathcc -c -ipa main.c
 $ pathcc -c -ipa foo.c
 $ pathcc -ipa main.o foo.o

2.1.2 Pre-defined Macros

The C/C++ compiler predefines certain macros for the preprocessor. Follow these steps to find out what these macros are:

Compile your program with the switches -dD and -keep.
Look in the resulting .i file to see the list of pre-defined macros and their corresponding definitions.

For example:

 $ pathcc -dD -keep foo.c
 $ cat foo.i

Previous: Using C/C++ Compiler, Up: Using Path64

2.2 The x86 Path64 Fortran Compiler

2.2.1 Using the Fortran compiler

The x86 Path64 Fortran compiler is invoked by the command:

 $ pathf90 <input files>

 $ pathf95 <input files>

By default, input files with suffixes of .F or .f are treated as fixed-form files, whereas input files with suffixes of .F90, .f90, .F95, or .f95 are treated as free-form files. This default behavior can be overridden by specifying the switches -fixedform or -freeform.

By default, input files with suffixes of .F, .F90, or .F95 will be preprocessed using the C preprocessor. This default behavior can be overridden by specifying the switches -cpp or -ftpp.

You can also specify other options or switches to the Fortran compiler. See x86 Path64 Option Summary, for a list of these options and switches.

For example, to explicitly control the optimization level used by the compiler:

 $ pathf90 -Ofast main.f sub.f

 $ pathf90 -c -ipa main.f
 $ pathf90 -c -ipa sub.f
 $ pathf90 -ipa main.o sub.o

2.2.2 Pre-defined macros

The Fortran compiler predefines certain macros for the preprocessor. Depending on which preprocessor is used, different macros are pre-defined. Follow these steps to find out what these macros are:

If the C preprocessor is used (-cpp):

Compile your program with the switches -Wp,-dD -E.
The list of pre-defined macros and their corresponding definitions will be written to the stdout file.

For example:

 $ pathf90 -Wp,-dD -E foo.f -cpp > foo.i
 $ cat foo.i

If the Fortran preprocessor is used (-ftpp):

Only the following macros are pre-defined:

 LANGUAGE_FORTRAN 1
 LANGUAGE_FORTRAN90 1
 _LANGUAGE_FORTRAN90 1
 unix 1
 __unix 1

2.2.3 Fortran Modules

After a Fortran module is compiled, the compiler generates a file called foo.mod (where foo is the name of the module). By default this file is placed in the same directory where the compilation command is issued. This default behavior can be overridden by specifying the switch -module.

When compiling a Fortran file that uses the foo module, by default the Fortran compiler will look for the file foo.mod in the same directory where the compilation command is issued. This default behavior can be overridden by specifying the switch -Idirectory.

Files containing modules that are to be used by other files must be compiled before the other files. This can be accomplished by any or all of the following:

Modules must appear before their uses in the same source file.
Files containing modules that are to be used by other files must be compiled before the other files are compiled.
Files containing modules that are to be used by other files must appear before the other files in the same compilation command.

After the Fortran compiler compiles a file containing a module, the compiler generates an object file (.o) as well as the module information file (.mod), even if the file contains nothing other than just the module. This object file must be linked with the rest of the program to generate an executable.

Next: Compatibility, Previous: Using Path64, Up: Top

3 x86 Path64 Command Options

When you invoke x86 Path64, it normally does preprocessing, compilation, assembly and linking. The “overall options” allow you to stop this process at an intermediate stage. For example, the -c option says not to run the linker. Then the output consists of object files output by the assembler.

Other options are passed on to one stage of processing. Some options control the preprocessor and others the compiler itself. Yet other options control the assembler and linker; most of these are not documented here, since you rarely need to use any of them.

Most of the command line options that you can use with Path64 are useful for C programs; when an option is only useful with another language (usually C++), the explanation says so explicitly. If the description for a particular option does not mention a source language, you can use that option with all supported languages.

See Compiling C++ Programs, for a summary of special options for compiling C++ programs.

The pathcc program accepts options and file names as operands. Many options have multi-letter names; therefore multiple single-letter options may not be grouped: -dr is very different from -d -r.

You can mix options and other arguments. For the most part, the order you use doesn't matter. Order does matter when you use several options of the same kind; for example, if you specify -L more than once, the directories are searched in the order specified.

Many options have long names which start with -f or with -W—for example, -funsafe-math-optimizations, -Wformat and so on. Options of the form -fflag specify machine-independent flags. Most of these have both positive and negative forms; the negative form of -ffoo would be -fno-foo. This manual typically documents only one of these two forms, whichever one is not the default or the one you typically will use. You can figure out the other form by either removing no- or adding it.

See Option Index, for an index to Path64's options.

Option Summary: Brief list of all options, without explanations.
Overall Options: Controlling the kind of output: an executable, object files, assembler files, or preprocessed source.
Directory Options: Where to find header files and libraries. Where to find the compiler executable files.
Invoking pathCC: Compiling C++ programs.
C Dialect Options: Controlling the variant of C/C++ language compiled.
Fortran Dialect Options: Controlling the variant of Fortran language compiled.
Language Feature Options: Options to control language features
Language Independent Options: Options which are Language Independent
Optimize Options: How much optimization?
Preprocessor Options: Controlling header files and macro definitions. Also, getting dependency information for Make.
Assembler Options: Passing options to the assembler.
Link Options: Specifying libraries and so on.
Code Gen Options: Specifying conventions for function calls, data layout
Target Options: Specifying hardware or running a cross-compiler.
Diagnostic Options: Controlling diagnostics.
Debugging Options: Symbol tables, measurements, and debugging dumps.
Warning Options: How picky should the compiler be? and register usage.
Environment Variables: Env vars that affect Path64.

Next: Overall Options, Up: Invoking Path64

3.1 Option Summary

Here is a summary of all the options, grouped by type. Explanations are in the following sections.

Overall Options

See Options Controlling the Kind of Output.

 -c -S -E -o file -copyright -help -help:string 
 -keep -LIST: -LIST:all_options -LIST:notes -LIST:options -LIST:symbols 
 -r -show -show-defaults -show0 -showt -dumpversion -v -version -###

Directory Options

See Options for Directory Search.

 -Idir -iquotedir -isystemdir -Ldir 
 -nostdinc -isysrootdir

C/C++ Language Options

See Options Controlling C/C++ Dialect.

 -ansi -fgnu-keywords -fno-gnu-keywords -fms-extensions 
 -fno-builtin -fno-common -fprefix-function-name -fpack-struct 
 -fshort-double -fshort-enums -fshort-wchar -f[no-]signed-bitfields 
 -f[no-]signed-char -f[no-]strict-aliasing -gnuN 
 -std=standard -traditional

C++ Language Options

See Options Controlling C++ Dialect.

 -fabi-version=N -f[no-]check-new -f[no-]exceptions 
 -f[no-]gnu-exceptions -f[no-]rtti -fuse-cxa-atexit

Fortran Language Options

See Options to Control Language Features.

 -ansi -auto-use module_name -byteswapio -colN
 -convert conversion -d-lines -default64 -exten-source 
 -noextend-source -nog77mangle -pad-char-literals -rreal_spec -uname

Language Feature Options

See Options to Control Language Features.

 -LANG:copyinout -LANG:formal_deref_unsafe -LANG:global_asm 
 -LANG:heap_allocation_threshold -LANG:IEEE_minus_zero -LANG:IEEE_save 
 -LANG:recursive -LANG:rw_const _LANG:short_circuit_conditionals

Language Independent Options

See Options which are Language Independent.

 -alignN -backslash -f[no-]unwind-tables -finhibit-size-directive 
 -fpic fPIC -fno-ident -HP -HUGEPAGE -HP:bdt -HP:heap 
 -HUGEPAGE:bdt -HUGEPAGE:heap -ignore-suffix -pathcc -no-pathcc
 -nobool -U name

Optimization Options

See Options that Control Optimization.

Options that Control Feedback Directed Optimizations

 -fb-create -fb-opt -fb-phase -finstrument-functions

Options that Control Glogal Optimizations

 -apo -O0 -O1 -O2 -O3 -Os -Ofast 
 -WOPT:aggstr -WOPT:const_pre -WOPT:if_conv -WOPT:ivar_pre
 -WOPT:mem_opnds -WOPT:retype_expr -WOPT:unroll -WOPT:val

Options that Control General Optimizations

 -f[no-]fast-math -ffloat-store -fno-math-errno 
 -f[no-]unsafe-math-optimizations -m87-precision -noexpopt 
 -openmp -mp -OPT:alias -OPT:align_unsafe -OPT:asm_memory 
 -OPT:bb -OPT:cis -OPT:cyg_instr -OPT:div_split -OPT:early_mp
 -OPT:early_intrinsics -OPT:fast_bit_intrinsics -OPT:fast_complex 
 -OPT:fast_exp -OPT:fast_io -OPT:fast_math -OPT:fast_nint 
 -OPT:fast_sqrt -OPT:fast_stdlib -OPT:fast_trunc -OPT:fold_reassociate 
 -OPT:fold_unsafe_relops -OPT:fold_unsigned_relops -OPT:goto 
 -OPT:IEEE_arithmetic -OPT:IEEE_NaN_inf -OPT:inline_intrinsics 
 -OPT:keep_ext -OPT:malloc_algorithm -OPT:malloc_alg 
 -OPT:Ofast -OPT:Olimit -OPT:pad_common -OPT:recip -OPT:reorg_common
 -OPT:roundoff -OPT:ro -OPT:rsqrt -OPT:space -OPT:speculate
 -OPT:transform_to_memlib -OPT:treeheight -OPT:unroll_analysis 
 -OPT:unroll_level -OPT:unroll_times_max -OPT:unroll_size 
 -OPT:wrap_around_unsafe_opt

Options that Control Interprocedural Optimizations

 -f[no-]implicit-inline-templates -f[no-]implicit-templates
 -f[no-]inline -inline -INLINE -noinline -f[no-]inline-functions
 -fkeep-inline-functions -INLINE:all -INLINE:aggressive 
 -INLINE:list -INLINE:must -INLINE:never -INLINE:none -INLINE:preempt
 -ipa -IPA -IPA:addressing -IPA:aggr_cprop -IPA:alias -IPA:callee_limit
 -IPA:cgi -IPA:clone_list -IPA:common_pad_size _IPA:cprop -IPA:ctype
 -IPA:depth -IPA:dfe -IPA:dve -IPA:echo -IPA:field_reorder
 -IPA:forcedepth -IPA:ignore_lang -IPA:inline -IPA:keeplight
 -IPA:linear -IPA:map_limit -IPA:maxdepth -IPA:max_jobs -IPA:min_hotness
 -IPA:multi_clone -IPA:node_bloat -IPA:plimit -IPA:pu_reorder
 -IPA:relopt -IPA:small_pu -IPA:sp_partition -IPA:space -IPA:specfile
 -IPA:use_intrinsic

Options that Control Loop Nest Optimizations

 -LNO:apo_use_feedback -LNO:build_scalar_reductions -LNO:blocking
 -LNO:blocking_size -LNO:fission -LNO:full_unroll -LNO:fu
 -LNO:full_unroll_size -LNO:full_unroll_outer -LNO:fusion 
 -LNO:fusion_peeling_limit -LNO:gather_scatter -LNO:hoistif
 -LNO:ignore_feedback -LNO:ignore_pragmas -LNO:local_pad_size
 -LNO:minvariant -LNO:minvar -LNO:non_blocking_loads -LNO:oinvar
 -LNO:opt -LNO:ou_prod_max -LNO:outer -LNO:outer_unroll_max 
 -LNO:ou_max -LNO:parallel_overhead -LNO:prefetch -LNO:prefetch_ahead
 -LNO:prefetch_verbose -LNO:processors -LNO:sclrze -LNO:simd
 -LNO:simd_reduction -LNO:simd_verbose -LNO:svr_phase1 
 -LNO:trip_count_assumed_when_unknown -LNO:trip_count -LNO:vintr
 -LNO:vintr_verbose -LNO:interchange -LNO:unswitch 
 -LNO:unswitch_verbose -LNO:outer_unroll -LNO:ou -LNO:outer_unroll_deep
 -LNO:ou_deep -LNO:outer_unroll_further -LNO:ou_further 
 -LNO:outer_unroll_max -LNO:ou_max -LNO:pwr2 -LNO:assoc 
 -LNO:cmp -LNO:cs -LNO:is_mem -LNO:ls -LNO:ps -LNO:tlb -LNO:tlbcmp
 -LNO:tlbdmp -LNO:assume_unknown_trip_count -LNO:pf -LNO:prefetch
 -LNO:prefetch_ahead -LNO:prefetch_manual

Preprocessor Options

See Options Controlling the Preprocessor.

 -A predicate -A -predicate -C -cpp -dD -DI -dM -dN
 -Dname -Dvar -fcoco -fe -f[no-]preprocessed -ftpp
 -M -macro-expand -MD -MDtarget -MDupdate -MF -MG -MM -MMD -MP
 -MQ -MT -nocpp -no-gcc -P -Uname -Wp,option

Assembler Option

See Passing Options to the Assembler.

 -fno-asm -Wa,option

Linker and Library Options

See Options for Linking.

 -ar -c -S -E -f[no-]fast-stdlib -H -llibrary
 -objectlist -nostartfiles -nodefaultlibs -nostdinc -nostdinc++
 -nostdlib -shared -shared-libgcc -static-libgcc -static --static
 -static-data -stdinc -symbolic -Xlinker -Wl,option

Code Generation Options

See Options for Code Generation Conventions.

 -CG:cflow -CG:cmp_peep -CG:compute_to -CG:cse_regs -CG:gcm
 -CG:inflate_reg_request -CG:load_exe -CG:local sched_alg -CG:locs_best
 -CG:locs_reduce_prefetch -CG:locs_shallow_depth -CG:movnti -CG:p2align
 -CG:p2align_freq -CG:post_local_sched -CG:pre_local_sched
 -CG:prefer_legacy_regs -CG:prefetch -CG:ptr_load_use
 -CG:push_pop_int_saved_regs -CG:sse_cse_regs -CG:unroll_fb_req
 -CG:use_prefetchnta -CG:use_test -GRA:home -GRA:optimize_boundary
 -GRA:prioritize_by_density -GRA:unspill

Target Options

See Specifying Target Environment and Machine.

 -TENV:frame_pointer -TENV:simd_dmask -TENV:simd_imask 
 -Tenv:simd_omask -TENV:simd_pmask -TENV:simd_umask 
 -TENV:simd_zmask -TENV:X

Machine Dependent Options

See Hardware Models and Configurations. i386 and x86-64 Options

 -march -mtune -mcpu -m[no-]sse -m[no-]sse2
 -m[no-]sse3 -m[no-]sse4a -m[no-]3dnow -m32 -m64 -mcmodel

Diagnostic Options

See Options to Control Diagnostic.

 -C -clist -CLIST: -CLIST:dotc_file -CLIST:doth_file
 -CLIST:emit_pfetch -CLIST:linelength -CLIST:show -flist
 -FLIST: -FLIST:ansi_format -FLIST:emit_pfetch -FLIST:ftn_file
 -FLIST:linelength -FLIST:show -f[no-]permissive -fullwarn
 -pedantic-errors -trapuv -zerouv

Debugging Options

See Options for Debugging Your Program.

 -dD -dI -dM -dN -fprofile-arcs -frandom-seed 
 -ftest-coverage -g -g0 -g1 -g2 -g3 -gdwarf-2 -gdwarf-20
 -gdwarf-21 -gdwarf-22 -gdwarf-23 -p -pg -profile

Warning Options

See Options to Request or Suppress Warnings.

 -w -Wall -Wbad-function-cast -W[no-]deprecated 
 -W[no-]disabled-optimization -W[no-]div-by-zero -W[no-]endif-labels
 -W[no-]error -W[no-]float-equal -W[no-]import -W[no-]larger-than
 -Wno-deprecated-declarations -woff -woffall -woffoptions -woffnum
 -Wundef -Wno-undef -W[no-]uninitialized -W[no-]unknown-pragmas
 -W[no-]unreachable-code -W[no-]unused -W[no-]unused_function
 -W[no-]unused-label -W[no-]unused-parameter -W[no-]unused-value
 -W[no-]unused-variable -W[no-]write-strings

Warning Options for C/C++ Only

 -Waggregate-return -W[no-]cast-align -W[no-]char-subscripts
 -W[no-]comment -W[no-]conversion -Wno-declaration-after-statement 
 -W[no-]format -W[no-]format-nonliteral -W[no-]format-security
 -w[no-]-id-clash -W[no-]implicit -W[no-]implicit-function-declaration
 -W[no-]implicit-int -W[no-]inline -W[no-]main -W[no-]missing-braces
 -W[no-]missing-declarations -W[no-]missing-format-attribute 
 -W[no-]missing-noreturn -W[no-]missing-prototypes -W[no-]multichar
 -W[no-]nested-externs -Wno-cast-qual -Wno-format-extra-args
 -Wno-format-y2k -Wnonnull -Wno-non-template-friend
 -W[no-]non-virtual-dtor -Wno-pmf-conversions -W[no-]old-style-cast
 -W[no]overloaded-virtual -W[no-]packed -W[no-]padded -W[no-]parentheses
 -W[no-]pointer-arith -W[no-]redundant-decls -W[no-]redundant-decls
 -W[no-]reorder -W[no-]return-type -W[no-]sequence-point -W[no-]shadow
 -W[no-]sign-compare -W[no-]sign-promo -W[no-]strict-aliasing 
 -W[no-]strict-prototypes -W[no-]switch -Wswitch-default -Wswitch-enum
 -W[no-]system-headers -W[no-]synth -W[no-]traditional -W[no-]trigraphs

Some command line options provide a group of suboptions. The x86 Path64 compiler supports a number of these group options, for example:

-CG:: Code Generation
-CLIST:: C Listing
-FLIST:: Fortran Listing
-GRA:: Global Register Allocator
-HUGEPAGE:: Huge Pages
-INLINE:: Subprogram Inlining
-IPA:: Interprocedural Analyzer
-LANG:: Language
-LIST:: Listing
- LNO:: Loop Nest Optimizer
-OPT:: General Optimizer
-TENV:: Target Environment
-WOPT:: Global Optimizer Modifier

Group options accept several suboptions allowing the user to specify a setting for each suboption. The general usage format is:

 -GROUP_OPTION:question=answer

To specify multiple suboptions:

either use colons to separate each suboption
or specify multiple options on the command line.

The following command lines are equivalent:

 % pathcc -LIST:notes=ON -LIST:symbols=OFF foo.c
 % pathcc -LIST:notes=ON:symbols=OFF foo.c

Some answer to suboptions to group options are specified with a setting that either enables or disables the feature. To enable a feature, specify the suboption either alone or with =1, =ON, or =TRUE. To disable a feature, specify the suboption with either =0, =OFF, or =FALSE. The following command lines are equivalent:

 % pathcc -OPT:recip=ON:space=OFF:speculate=TRUE foo.c
 % pathcc -OPT:recip:space=0:speculate=ON foo.c

Note for brevity, this document uses only the ON|OFF settings to suboptions. The compiler also accepts 1|0 and TRUE|FALSE as settings.

Group options -INLINE: and -IPA: have noted differences for the GROUP_OPTION without any suboptions. Additionally specifying:

-INLINE is equivalent to -inline
-IPA is equivalent to -ipa
-clist is equivalent to -CLIST:=ON.
-flist is equivalent to enabling all the -FLIST options.
-HUGEPAGE is equivalent to -HUGEPAGE:heap=ON.

Next: Directory Options, Previous: Option Summary, Up: Invoking Path64

3.2 Options Controlling the Kind of Output

Compilation can involve up to four stages: preprocessing, compilation proper, assembly and linking, always in that order. x86 Path64 is capable of preprocessing and compiling several files either into several assembler input files, or into one assembler input file; then each assembler input file produces an object file, and linking combines all the object files (those newly compiled, and those specified as input) into an executable file.

For any given input file, the file name suffix determines what kind of compilation is done:

file.c: C source code which must be preprocessed.
file.cc
file.cxx
file.cpp
file.C: C++ source code which must be preprocessed. Note that in .cxx, the last two letters must both be literally x. Likewise, .C refers to a literal capital C.
file.i: C source code which should not be preprocessed. Note to preserve a file.i invoke the compiler with the -E command option.
file.ii: C++ source code which should not be preprocessed.
file.h: C/C++ header file to be turned into a precompiled header.
file.hh
file.H: C++ header file to be turned into a precompiled header.
file.f: Fixed format Fortran source code which should not be preprocessed.
file.f90
file.f95: Freeform Fortran source code which should not be preprocessed.
file.F: Fixed format Fortran source code which must be preprocessed (with the traditional preprocessor).
file.F90
file.F95: Freeform Fortran source code which must be preprocessed (with the traditional preprocessor).
file.s: Assembler code. Note to preserve a file.s invoke the compiler with the -S command option.
file.S: Assembler code which must be preprocessed.
file.o
other: An object file to be fed directly into linking. Any file name with no recognized suffix is treated this way.
file.a: A static library of object files
file.so: A library of shared object files

If you only want some of the stages of compilation, you can use filename suffixes to tell the compiler where to start, and one of the options -c, -S, or -E to say where the compiler is to stop.

-c

Compile or assemble the source files, but do not link. The linking stage simply is not done. The ultimate output is in the form of an object file for each source file.

By default, the object file name for a source file is made by replacing the suffix .c, .i, .s, etc., with .o.

Unrecognized input files, not requiring compilation or assembly, are ignored. Not to be used with -r since the -c option nullifies the -r option.

-S

Stop after the stage of compilation proper; do not assemble. The output is in the form of an assembler code file for each non-assembler input file specified.

By default, the assembler file name for a source file is made by replacing the suffix .c, .i, etc., with .s.

Input files that don't require compilation are ignored.

-E

Stop after the preprocessing stage; do not run the compiler proper. The output is in the form of preprocessed source code with line directives, which is sent to the standard output. Use -P to suppress line directives.

Input files which don't require preprocessing are ignored. The-E option nullifies the -nocpp option.

-o file

Place output in file file. This applies regardless to whatever sort of output is being produced, whether it be an executable file, an object file, an assembler file or preprocessed C code.

If -o is not specified, the default is to put an executable file in a.out, the object file for source.suffix in source.o, its assembler file in source.s, a precompiled header file in source.suffix.gch, and all preprocessed C source on standard output.

-copyright

Display the copyright for the Path64 compiler.

-help

-help:string

Print (on the standard output) a description of the command line options understood by pathcc, pathCC, and open95.

If -help: is specified a description of the command line options that contain a given string is printed.

-keep

Instructs the compiler to write all intermediate compilation files. Files written after final compilation are:

the compiler generated preprocessed source code file, filename.i
the compiler generated assembly language file, filename.s

Note if IPA is enabled and the assembly language file is required (i.e. filename.s), option -IPA:keeplight=OFF must be specified.

-LIST:question=answer

The -LIST: option group instructs the compiler to emit information which gets written to a listing file with the suffix .lst. The options in this group are:

-LIST:=ON|OFF: Instructs the compiler to write the list file. The emitted data to the listing file includes a list of specified options. The default is -LIST:=ON if any -LIST:question=answer is specified, otherwise the default is -LIST:=OFF.
-LIST:all_options=ON|OFF: Instructs the compiler to emit a list of supported options. The default is -LIST:all_options=OFF.
-LIST:notes=ON|OFF: Specifying LIST:notes=OFF instructs the compiler not to insert a list of comments within the assembly listing that discribes various actions taken by the compiler (e.g., software pipelining). Note enabling the generation of the assembly listing is a prerequisite to this option (e.g., by specifying -S). The default is -LIST:notes=ON.
-LIST:options=ON|OFF: Instructs the compiler to list the command-line options directly or indirectly modified as a side effect of other options. The default is -LIST:options=OFF.
-LIST:symbols=ON|OFF: Instructs the compiler to list information regarding the symbols (i.e. variables) managed by the compiler. The default is -LIST:symbols=OFF.

-r

Instructs the compiler to generate a relocatable object file (.o) and then stop.

-show

Print the compilation phases as they execute with appropriate arguments and input/output files.

-show-defaults

Print (on the standard output) a description of target specific command line options for each tool. Also prints the options in the compiler.defaults file.

For C/C++ -show-defaults will also print the compatible gcc version.

-show0

Print (on the standard output) the compilation phases without invoking the compiler.

-showt

Print (on the standard output) the time required by each compilation phase.

-dumpversion

Print the compiler version (for example, 3.0)—and don't do anything else.

-v

Print (on the standard output) the compiler driver, preprocessor, compiler proper, and the commands specified to run on the compilation phases.

-version

Print (on the standard output) the version number of the invoked compiler.

-###

Like -v except the commands are not executed and all command arguments are quoted. This is useful for shell scripts to capture the driver-generated command lines.

Next: Invoking pathCC, Previous: Overall Options, Up: Invoking Path64

3.3 Options for Directory Search

These options specify directories to search for header files, for libraries and for parts of the compiler. Note the space between the option and the directory name, dir, is not required (e.g., L dir is equivalent to Ldir).

-I dir

Add the directory dir to the head of the list of directories to be searched for header files. This can be used to override a system header file, substituting your own version, since these directories are searched before the system header file directories. However, you should not use this option to add directories that contain vendor-supplied system header files (use -isystem for that). If you use more than one -I option, the directories are scanned in left-to-right order; the standard system directories come after.

The -I is used for the following types of files:

File names that do not begin with a slash (/) character and are located on the INCLUDE statement of the Fortran source programs.
File names that do not begin with a slash (/) character and are located in the #include statement of a preprocessing directives.
Files specified by Fortran USE statements.

If a standard system include directory, or a directory specified with -isystem, is also specified with -I, the -I option will be ignored. The directory will still be searched but as a system directory at its normal position in the system include chain. If you really need to change the search order for system directories, use the -nostdinc and/or -isystem options.

The compiler searches for files in the following order:

first, in the directory that contains the input source file
second, in the direcories specified by option Idir
third, in the standard /usr/include/ directory.

-iquote dir

Add the directory dir to the head of the list of directories to be searched for header files only for the case of #include "file"; they are not searched for #include <file>, otherwise just like -I.

-isystem dir

Search dir for header files, after all directories specified by â€˜-Iâ€™ but before the standard system directories. Mark it as a system directory, so that it gets the same special treatment as is applied to the standard system directories.

-L dir

Add directory dir to the list of directories to be searched for -l. See -llibrary. Note for XPG4 the order of searching for libraries named in -l is to look in the specified directory, dir, before looking in the default directory. Multiple instances of -L can be specified and are searched in the specified order left-to-right.

-nostdinc

Do not search the standard system directories for header files. Only the directories you have specified with -I options (and the directory of the current file, if appropriate) are searched.

-isysroot dir

This option is like the --sysroot option, but applies only to header files. See the --sysroot option for more information.

Next: C Dialect Options, Previous: Directory Options, Up: Invoking Path64

3.4 Compiling C++ Programs

C++ source files conventionally use one of the suffixes .C, .cc, .cpp, or .cxx; C++ header files often use .hh or .H; and preprocessed C++ files use the suffix .ii. x86 Path64 recognizes files with these names and compiles them as C++ programs even if you call the compiler the same way as for compiling C programs (usually with the name pathcc).

However, the use of pathcc does not add the C++ library. pathCC is a program that calls x86 Path64 and treats .c, .h and .i files as C++ source files instead of C source files unless -x is used, and automatically specifies linking against the C++ library. This program is also useful when precompiling a C header file with a .h extension for use in C++ compilations.

When you compile C++ programs, you may specify many of the same command-line options that you use for compiling programs in any language; or command-line options meaningful for C and related languages; or options that are meaningful only for C++ programs. See Options Controlling C Dialect, for explanations of options for languages related to C and C++.

Next: Fortran Dialect Options, Previous: Invoking pathCC, Up: Invoking Path64

3.5 Options Controlling C/C++ Dialect

The following options control the dialect of C (or languages derived from C, such as C++) that the compiler accepts:

-ansi

In C mode, this is equivalent to -std=c89. In C++ mode, it is equivalent to -std=c++98.

This turns off certain features of x86 Path64 that are incompatible with ISO C90 (when compiling C code), or of standard C++ (when compiling C++ code), such as the asm and typeof keywords. It also enables the undesirable and rarely used ISO trigraph feature. For the C compiler, it disables recognition of C++ style // comments as well as the inline keyword.

The alternate keywords __asm__, __extension__, __inline__ and __typeof__ continue to work despite -ansi. You would not want to use them in an ISO C program, of course, but it is useful to put them in header files that might be included in compilations done with -ansi.

The -ansi option does not cause non-ISO programs to be rejected gratuitously. For that, -pedantic is required in addition to -ansi. See Warning Options.

The macro __STRICT_ANSI__ is predefined when the -ansi option is used. Some header files may notice this macro and refrain from declaring certain functions or defining certain macros that the ISO standard doesn't call for; this is to avoid interfering with any programs that might use these names for other things.

Functions that would normally be built in but do not have semantics defined by ISO C (such as alloca and ffs) are not built-in functions when -ansi is used.

-fgnu-keywords

-fno-gnu-keywords

-fgnu-keywords instructs the compiler to recognize typeof as a keyword. -fno-gnu-keywords specifies to not recognize typeof as a keyword, so that code can use this word as an identifier. You can use the keyword __typeof__ instead. -ansi implies -fno-gnu-keywords. The default is -fno-gnu-keywords.

-fms-extensions

Accept some non-standard constructs used in Microsoft header files. This option disables pedantic warnings about constructs used in MFC, such as implicit int and getting a pointer to member function via non-standard syntax.

Some cases of unnamed fields in structures and unions are only accepted with this option.

-fno-builtin

Don't recognize built-in functions that do not begin with __builtin_ as prefix. See Other built-in functions provided by x86 Path64 for details of the functions affected, including those which are not built-in functions when -ansi or -std options for strict ISO C conformance are used because they do not have an ISO standard meaning. Note the x86 Path64 C/C++ compiler does not support many of the __builtin functions.

Path64 normally generates special code to handle certain built-in functions more efficiently; for instance, calls to alloca may become single instructions that adjust the stack directly, and calls to memcpy may become inline copy loops. The resulting code is often both smaller and faster, but since the function calls no longer appear as such, you cannot set a breakpoint on those calls, nor can you change the behavior of the functions by linking with a different library. In addition, when a function is recognized as a built-in function, Path64 may use information about that function to warn about problems with calls to that function, or to generate more efficient code, even if the resulting code still contains calls to that function. For example, warnings are given with -Wformat for bad calls to printf, when printf is built in, and strlen is known not to modify global memory.

If you wish to enable built-in functions selectively when using -fno-builtin, you may define macros such as:

 #define abs(n) __builtin_abs ((n))
 #define strcpy(d, s) __builtin_strcpy ((d), (s))

-fno-common

In C, allocate even uninitialized global variables in the data section of the object file, rather than generating them as common blocks. This has the effect that if the same variable is declared (without extern) in two different compilations, you will get an error when you link them. The only reason this might be useful is if you wish to verify that the program will work on other systems which always work this way.

-fprefix-function-name

Instruct the compiler to attach a prefix to all function names.

-fpack-struct[=n]

Without a value specified, pack all structure members together without holes. When a value is specified (which must be a small power of two), pack structure members according to this value, representing the maximum alignment (i.e. objects with default alignment requirements larger than this will be potentially unaligned at the next fitting location).

Warning: the -fpack-struct switch causes the compiler to generate code that is not binary compatible with code generated without that switch. Additionally, it makes the code suboptimal. Use it to conform to a non-default application binary interface.

-fshort-double

Use the same size for double as for float.

Warning: the -fshort-double switch causes the compiler to generate code that is not binary compatible with code generated without that switch. Use it to conform to a non-default application binary interface.

-fshort-enums

Allocate to an enum type only as many bytes as it needs for the declared range of possible values. Specifically, the enum type will be equivalent to the smallest integer type which has enough room.

Warning: the -fshort-enums switch causes the compiler to generate code that is not binary compatible with code generated without that switch. Use it to conform to a non-default application binary interface.

-fshort-wchar

Override the underlying type for wchar_t to be short unsigned int instead of the default for the target.

Warning: the -fshort-wchar switch causes the compiler to generate code that is not binary compatible with code generated without that switch. Use it to conform to a non-default application binary interface.

-fsigned-bitfields

-fno-signed-bitfields

These options control whether a bit-field is signed or unsigned, when the declaration does not use either signed or unsigned. By default, such a bit-field is signed, because this is consistent; the basic integer types such as int are signed types.

-fsigned-char

-fno-signed-char

Let the type char be signed, like signed char.

Each kind of machine has a default for what char should be. It is either like unsigned char by default or like signed char by default.

Ideally, a portable program should always use signed char or unsigned char when it depends on the signedness of an object. But many programs have been written to use plain char and expect it to be signed, or expect it to be unsigned, depending on the machines they were written for. This option, and its inverse, let you make such a program work with the opposite default.

The type char is always a distinct type from each of signed char or unsigned char, even though its behavior is always just like one of those two.

-fstrict-aliasing

-fno-strict-aliasing

Allows the compiler to assume the strictest aliasing rules applicable to the language being compiled. For C (and C++), this activates optimizations based on the type of expressions. In particular, an object of one type is assumed never to reside at the same address as an object of a different type, unless the types are almost the same. For example, an unsigned int can alias an int, but not a void* or a double. A character type may alias any other type.

Pay special attention to code like this:

 union a_union {
 int i;
 double d;
 };
 
 int f() {
 a_union t;
 t.d = 3.0;
 return t.i;
 }

The practice of reading from a different union member than the one most recently written to (called “type-punning”) is common. Even with -fstrict-aliasing, type-punning is allowed, provided the memory is accessed through the union type. So, the code above will work as expected. However, this code might not:

 int f() {
 a_union t;
 int* ip;
 t.d = 3.0;
 ip = &t.i;
 return *ip;
 }

Every language that wishes to perform language-specific alias analysis should define a function that computes, given a tree node, an alias set for the node. Nodes in different alias sets are not allowed to alias. For an example, see the C front-end function c_get_alias_set.

Enabled at levels -O2, -O3, -Os.

-gnuN

Instructs the compiler to generate code that is compatible with the GNU N series of compilers. Where:

N=3 implies GCC 3.3. The default is -gnu3 if the host system default compiler is GCC 3.
N=4 implies GCC 4.2. The default is -gnu4 if the host system default compiler is GCC 4.
N=40 implies GCC 4.0. The default is -gnu40 if the host system default compiler is GCC 4.0.

Note invoke the compiler with -show-defaults to display the host system default.

-std=standard

Determine the language standard. See Language Standards Supported by x86 Path64, for details of these standard versions. This option is currently only supported when compiling C or C++.

The compiler can accept several base standards, such as c89 or c++98, and GNU dialects of those standards, such as gnu89 or gnu++98. By specifing a base standard, the compiler will accept all programs following that standard and those using GNU extensions that do not contradict it. For example, -std=c89 turns off certain features of GCC that are incompatible with ISO C90, such as the asm and typeof keywords, but not other GNU extensions that do not have a meaning in ISO C90, such as omitting the middle term of a ?: expression. On the other hand, by specifing a GNU dialect of a standard, all features the compiler support are enabled, even when those features change the meaning of the base standard and some strict-conforming programs may be rejected. The particular standard is used by -pedantic to identify which features are GNU extensions given that version of the standard. For example -std=gnu89 -pedantic would warn about C++ style // comments, while -std=gnu99 -pedantic would not.

A value for this option must be provided; possible values are

c89
iso9899:1990: Support all ISO C90 programs (certain GNU extensions that conflict with ISO C90 are disabled). Same as -ansi for C code.
iso9899:199409: ISO C90 as modified in amendment 1.
c99
c9x
iso9899:1999
iso9899:199x: Support all ISO C99 programs.
gnu89: GNU dialect of ISO C90 (including some C99 features). This is the default for C code.
gnu99
gnu9x: GNU dialect of ISO C99. The name gnu9x is deprecated.
c++98: The 1998 ISO C++ standard plus amendments. Same as -ansi for C++ code.
gnu++98: GNU dialect of -std=c++98.

The default is -std=gnu89 for C code and -std=gnu++98 for C++ code

-traditional

Formerly, these options caused the compiler to attempt to emulate a pre-standard C compiler. They are now only supported with the -E switch. The preprocessor continues to support a pre-standard mode. See the GNU CPP manual for details.

This section describes the command-line options that are only meaningful for C++ programs; but you can also use most of the compiler options regardless of what language your program is in. For example, you might compile a file firstClass.C like this:

 pathCC -g -frepo -O -c firstClass.C

In this example, only -frepo is an option meant only for C++ programs; you can use the other options with any language supported by x86 Path64.

Here is a list of options that are only for compiling C++ programs:

-fabi-version=N (C++ Only): Use version N of the C++ ABI. Version 2 is the version of the C++ ABI that first appeared in g++ 3.4. Version 1 is the version of the C++ ABI that first appeared in g++ 3.2. Version 0 will always be the version that conforms most closely to the C++ ABI specification. Therefore, the ABI obtained using version 0 will change as ABI bugs are fixed.
The default is -fabi-version=2 or version 2.
-fcheck-new (C++ Only)
-fno-check-new (C++ Only): Check that the pointer returned by operator new is non-null before attempting to modify the storage allocated. This check is normally unnecessary because the C++ standard specifies that operator new will only return 0 if it is declared throw(), in which case the compiler will always check the return value even without this option. In all other cases, when operator new has a non-empty exception specification, memory exhaustion is signalled by throwing std::bad_alloc. See also new (nothrow). -fno-check-new instructs the compiler to not check the result of operator new for null.
-fexceptions (C++ Only)
-fno-exceptions (C++ Only)
-fgnu-exceptions (C++ Only)
-fno-gnu-exceptions (C++ Only): Enable exception handling. Generates extra code needed to propagate exceptions. For some targets, this implies the compiler will generate frame unwind information for all functions, which can produce significant data size overhead, although it does not affect execution. If you do not specify this option, Path64 will enable it by default for languages like C++ which normally require exception handling, and disable it for languages like C that do not normally require it. However, you may need to enable this option when compiling C code that needs to interoperate properly with exception handlers written in C++. You may also wish to disable this option if you are compiling older C++ programs that don't use exception handling.
-frtti (C++ Only)
-fno-rtti (C++ Only): When specifying -frtti the compiler will emit runtime type information. -fno-rtti disables generating information about every class with virtual functions for use by the C++ runtime type identification features (dynamic_cast and typeid). If you don't use those parts of the language, you can save some space by using this flag. Note that exception handling uses the same information, but it will generate it as needed. The dynamic_cast operator can still be used for casts that do not require runtime type information, i.e. casts to void * or to unambiguous base classes.
-fuse-cxa-atexit (C++ Only): Register destructors for objects with static storage duration with the __cxa_atexit function rather than the atexit function. This option is required for fully standards-compliant handling of static destructors, but will only work if your C library supports __cxa_atexit.

Next: Language Feature Options, Previous: C Dialect Options, Up: Invoking Path64

3.6 Options Controlling Fortran Dialect

The following options control the dialect of Fortran that the compiler accepts:

-ansi

Instructs the compiler to emit messages regarding constructs that violate Fortran syntax rules and constraints. Including messages about obsolescent and deleted features. This option disables all nonstandard intrinsic functions and subroutines. Note specifying -ansi implies option -ffortran2003and when used concurrently with -fullwarn causes all messages to be generated (i.e. regardless of level).

-auto-use module_name[,module_name]...

Instruct the compiler to act as if a USE module_name statement was entered in the Fortran source code for each module_name. The compiler inserts USE statements in every program unit and interface body in the compiled source code. For example,

 pathf95 -auto-use mpi_interface

 pathf95 -auto-use shmem_interface

Note in some situations using -auto-use can increase compiler time.

-byteswapio

-byteswapio swaps bytes during I/O so that unformatted files on a little-endian processor are read and written in big-endian format (or vice versa.) Use the option when compiling the Fortran main program. Note the -byteswapio option affects record headers as well as data in sequential unformatted files. Setting the environment variable FILENV during program execution will supersede the compiled-in code generated option in favor of the choice established by the assign command.

-colN

Specifies the line width for fixed-format source lines. Set N to 72, 80, or 120.

-convert conversion

-convert conversion controls the swapping of bytes during I/O so that unformatted files on a little-endian processor are read and written in big-endian format (or vice versa). Use the option when compiling the Fortran main program. Note the -byteswapio option affects record headers as well as data in sequential unformatted files. Setting the environment variable FILENV during program execution will supersede the compiled-in code generated option in favor of the choice established by the command assign. The option supports three arguments

native: No conversion
little_endian: Files are little-endian
big_endian: Files are big-endian

The default is -convert native.

-d-lines

Instruct the compiler to insert a D in column 1 of compiled lines.

-default64

The compiler sets the sizes of default integer, real, logical, and double precision objects. -default64 causes the following options to go into effect: -r8 and -i8. Note calling a function in a specialized library requires that its 32-bit (or 64-bit) entry point be specified when 32-bit (or 64-bit) data is being used.

-extend-source

-noextend-source

The line length for fixed-format source files are set to 132 character-per-line. The default for fixed-format lines are 72 characters-per-line. See -colN, for more information on controlling line length.

-nog77mangle

Fortran symbol names are modified by the compiler by appending an underscore to the symbol name, e.g., symbol name foo in the source file becomes foo_ in the object file.

If the symbol name includes an underscore then the compiler will append a second underscore to the symbol name in the object file, e.g., foo_ and foo_bar in the source file becomes foo__ and foo_bar__ in the object file, respectively. nog77mangle suppresses the appending of the second underscore.

-pad-char-literals

Extend the length (i.e., by padding with blanks) of all character literal constants to the size of the default integer type and that are passed as actual arguments.

-rreal_spec

Specifies the default KIND specification for real values.

-r4: Use REAL(KIND=4) for real variables and COMPLEX(KIND=4) for complex variables.
-r8: Use REAL(KIND=8) for real variables and COMPLEX(KIND=8) for complex variables.

The default is -r4.

-uname

Instructs the compiler to assign the default type of the variable, name, to be undefined rather then using default Fortran 90 rules.

Next: Language Independent Options, Previous: Fortran Dialect Options, Up: Invoking Path64

3.7 Options to Control Language Features

The options described below can be used to control the features of the C/C++ or Fortran language.

-LANG:question=answer

Options in the -LANG: group can be used to control the set of features that are supported. For example, to compile code that does not conform with the Standard in one way or another. Note it may not always be possible, however, to link together object files, some of which have been compiled with a feature enabled and others with it disabled.

-LANG:copyinout=ON|OFF

If an array section is passed as an argument in a call, the compiler is instructed to copy the array section into a temporary array that will be passed as the argument in the call. -LANG:copyinout optimizes the accessing of array arguments by improving argument locality. Note the flag helps regulate the aggressiveness of this optimization and is mainly suited to Fortran code. When specifying global optimization -O2 or higher -LANG:copyinout=ON. The default is -LANG:copyinout=OFF.

-LANG:formal_deref_unsafe=ON|OFF (Fortran Only)

The compiler is instructed that it is unsafe to attempt any optimizations regarding the dereference of a formal parameter. The default is -LANG:formal_deref_unsafe=OFF.

-LANG:global_asm=ON|OFF

The compiler's assembler is instructed to allocate objects to sections if the program includes a file-scope assembly statement. -LANG:global_asm=ON causes some alignment optimizations to be suppressed allowing the allocations performed by the compiler to be compatible with the allocations in the assembly statement. The default is -LANG:global_asm=OFF.

-LANG:heap_allocation_threshold=size

Specifies the threshold when determining if to allocate an automatic array or compiler temporary on the heap rather than on the stack. Parameter size is in bytes and sets the threshold. Setting size to -1 implies all objects are placed on the stack. Setting size to 0 implies all objects are placed on the heap. The default is -LANG:heap_allocation_threshold=-1 for maximum performance.

-LANG:IEEE_minus_zero=ON|OFF (Fortran only)

Instructs the compiler to acknowledge negative floating-point zeroes (i.e. -0.0). -LANG:IEEE_minus_zero=OFF disables the intrinsic function SIGN(3I), suppressing the minus sign on zero. This deters problems created by optimizations and hardware instructions that return a negative floating-point zero result from a positive floating-point zero value. Note use the -z option with the assign command to print the minus sign of a negative floating-point zero. The default is -LANG:IEEE_minus_zero=OFF.

-LANG:IEEE_save=ON|OFF (Fortran only)

When a procedure accesses a standard IEEE intrinsic module with a USE statement, then upon entry the floating-point flags, halt mode, and rounding mode must be saved. When exiting the halt and rounding mode must be restored and the saved floating-point flags must be logically OR with the current floating-point flags. To improve runtime set the option to OFF. The default is -LANG:IEEE_save=OFF.

-LANG:recursive=ON|OFF (Fortran only)

When set to ON a statically allocated local variable can be referenced or modified by a recursive procedure call. The statically allocated local variable must be stored in memory before making a call and reloaded afterward.

When set to OFF the compiler can safely assume a statically allocated local variable will not be referenced or modified by a procedure call and can optimize more aggressively.

In either mode, the compiler supports a recursive stack-based calling sequence. The difference is in the optimization of statically allocated local variables. The default is -LANG:recursive=OFF.

-LANG:rw_const=ON|OFF (Fortran Only)

Instructs the compiler to handle constant parameter as either read-only or read-write. If the compiler is instructed to handle a constant parameter as read-write, then extra code must be generated to accommodate the possibility of the constant parameter being changed in the called function. Note when turned OFF the compiler generates more efficient code but segmentation faults will occur when writing to the constant parameter. The default is -LANG:rw_const=OFF.

-LANG:short_circuit_conditionals=ON|OFF (Fortran Only)

The compiler is instructed to manage the logical .AND. and .OR. by applying a short-circuit methodology to the second operand. Note if determined unnecessary, the compiler will not evaluate the second operand even if problems occur in addition to the desired compilation effect. The default is -LANG:short_circuit_conditionals=ON.

Next: Optimize Options, Previous: Language Feature Options, Up: Invoking Path64

3.8 Options which are Language Independent

-alignN

Arranges for the data to be aligned on common blocks to a specified boundary. Selections for -alignN are as follows:

-align32: Align common blocks of data on 32-bit boundaries.
-align64: Align common blocks of data on 64-bit boundaries.

Objects smaller than the specified alignment (i.e. 32-bit or 64-bit) are aligned on boundaries according to the object size. For example if -align64 is selected:

object sizes less than 64-bits but at least 32-bits are aligned on 32-bit boundaries.
object sizes less than 32-bits but at least 16-bits are aligned on 16-bit boundaries.
object sizes less than 16-bits are aligned on 8-bit boundaries.

-backslash

Instructs the compiler to consider a backslash as a normal character instead of an escape character. Note specifying -backslash instructs the compiler not to pass the code through the preprocessor.

-funwind-tables

-fno-unwind-tables

Similar to -fexceptions, except that it will just generate any needed static data, but will not affect the generated code in any other way. You will normally not enable this option; instead, a language processor that needs this handling would enable it on your behalf. The default is -fno-unwind-tables.

-finhibit-size-directive

Don't output a .size assembler directive, or anything else that would cause trouble if the function is split in the middle, and the two halves are placed at locations far apart in memory. This option is used when compiling crtstuff.c; you should not need to use it for anything else.

-fpic

Generate position-independent code (PIC) suitable for use in a shared library, if supported for the target machine. Such code accesses all constant addresses through a global offset table (GOT). The dynamic loader resolves the GOT entries when the program starts (the dynamic loader is not part of the compiler; it is part of the operating system). If the GOT size for the linked executable exceeds a machine-specific maximum size, you get an error message from the linker indicating that -fpic does not work; in that case, recompile with -fPIC instead.

When this flag is set, the macros __pic__ and __PIC__ are defined to 1.

-fPIC

If supported for the target machine, emit position-independent code, suitable for dynamic linking and avoiding any limit on the size of the global offset table.

Position-independent code requires special support, and therefore works only on certain machines.

When this flag is set, the macros __pic__ and __PIC__ are defined to 2.

-fno-ident

Instruct the compiler to disregard the #ident directive.

-HP:question=answer[,argument=N,...]

-HUGEPAGE:question=answer[,argument=N,...]

-HP

-HUGEPAGE

The compiler supports command line options to use 2 MByte huge pages for heap and ”bdt”, where ”bdt” stands for bss, data and text segments. This option group is operating system (OS) dependent, refer to the release notes for more information on which OS versions are supported.

A mixed usage of huge pages and small pages is supported for heap allocation when huge page is not available. A mixed usage of huge pages and small pages for bss, data and text segments is not supported.

Currently, the compiler requires a modified version of the libhugetlbfs library functions, see the release notes or supported versions. Both a static link and dynamic link to the modified library functions are supported for huge page heap allocation, but only dynamic link is supported for huge page” bdt” mapping.

-HP:bdt=size

-HUGEPAGE:bdt=size

The compiler is instructed to use huge pages for bss, data, and text segments (a.k.a, bdt). A mixed usage of huge pages and small pages is currently not supported for option -HUGEPAGE:bdt=size (i.e. bss, data, and text). The sub-option can be set to:

2m: Instructs the compiler to use 2 MByte huge pages for bss, data, and text segments.

-HP:heap=size[,argument=N,...]

-HUGEPAGE:heap=size[,argument=N,...]

The compiler is instructed to use huge pages for the heap segment. A mixed usage of huge pages and small pages is currently supported for -HUGEPAGE:heap=size. The sub-option can be set to:

2m: Instructs the compiler to use 2 MByte huge pages for bss, data, and text segments.

Currently the huge page sub-option for the heap supports one argument, -HUGEPAGE:heap=2m,limit=N, where the value N is used to set the upper bound and represents a 32-bit integral number. If the limit argument is not specify or N is set to a negative number then no user-imposed limit is set and huge page usage is only limited by the resources on the target machine. For example, sub-options -HP:heap=2m and -HP:heap=2m,limit=-1 are equivalent and specify that the upper bound is limited by the target resources. If the value of N is set to zero the huge page usages for heap is suppressed.

-HP

-HUGEPAGE

-HUGEPAGE and -HP are abbreviated forms for sub-options -HUGEPAGE:heap=2m and -HP:heap=2m, respectively. For example:

 pathcc -HP foo.c

is equivalent to

 pathcc -HP:heap=2m foo.c

Examples for using huge pages are:

 pathcc -HUGEPAGE:bdt=2m -HUGEPAGE:heap=2m,limit=850 -o foo foo.c

or in a condensed form

 pathcc -HP:bdt=2m:heap=2m,limit=850 -o foo foo.c

Note the huge page library, libhugetlbfs, is not NUMA sensitive. It assumes that huge pages on all memory nodes in the system are available to all processes. It is recommended to use the limit argument to impose an upper bound on the huge page usage per process to avoid the situation that one process consumes all huge page resources and starves the rest.

If ”numctrl -m” is used to bind a process to a specific memory node, then the memory node must have enough huge pages to meet the demand. Therefore it is required to configure sufficient huge pages for all threads and all processes. Note the huge page library, libhugetlbfs, is not multithread safe.

-ignore-suffix

The -ignore-suffix flag instructs the compiler to ignore the suffix of the input source files. The language of the source file is designated by the compiler driver. Specifying -ignore-suffix forces the compiler driver pathcc to invoke the C compiler, pathCC to invoke the C++ compiler, and pathf95 to invoke the Fortarn compiler. By default the language of the source file is determined by the suffixes of the file (i.e. .c, .cpp, .C, .cxx, .f, .f90, and .s).

-pathcc

-no-pathcc

-pathcc instructs the compiler to define the __Path64__ macro and other predefined preprocessor macros. -no-pathcc instructs the compiler to disable these macros.

-nobool

Instruct the compiler to not allow boolean keywords.

-U name

Instructs the compiler to remove any initial definition of name.

Next: Preprocessor Options, Previous: Language Independent Options, Up: Invoking Path64

3.9 Options That Control Optimization

These options control various sorts of optimizations.

Without any optimization option, the compiler's goal is to reduce the cost of compilation and to make any debugging session produce the expected results. Statements are independent: if you stop the program with a breakpoint between statements, you can then assign a new value to any variable or change the program counter to any other statement in the function and get exactly the results you would expect from the source code.

Turning on optimization flags makes the compiler attempt to improve the performance and/or code size at the expense of compilation time and possibly the ability to debug the program.

The compiler performs optimization based on the knowledge it has of the program. Optimization levels -O and above, in particular, enable unit-at-a-time mode, which allows the compiler to consider information gained from later functions in the file when compiling a function. Compiling multiple files at once to a single output file in unit-at-a-time mode allows the compiler to use information gained from all of the files when compiling each of them.

Not all optimizations are controlled directly by a flag. Only optimizations that have a flag are listed.

Next: Global Options, Up: Optimize Options

3.9.1 Options that Control Feedback Directed Optimizations

Feedback directed optimizations (FDO) is used by the x86 Path64 compiler to improve performance. The program under development must be compiled at least twice. The first compilation generates an executable which contains extra instrumentation library calls required to gather feedback information. At runtime, this specified instrumented executable is used to gather the required profile information about the program. The profile data is then used in subsequent compilations to perform the necessary transformations to produce optimum code.

-fb-create filename

Instructs the compiler to generate an instrumented executable program from the source code under development. The instrumented executable produces feedback data files at runtime using an example dataset. filename specifies the name of the feedback data file generated by the instrumented executable.

 pathcc -O2 -ipa -fb-create fbdata -o foo foo.c

fbdata will contain the instrumented feedback data from the instrumented executable foo. The default is -fb-create is disabled.

-fb-opt filename

Instructs the compiler to perform a feedback directed compilation using the instrumented feedback data produced by the -fb-create option.

 pathcc -O2 -ipa -fb-opt fbdata -o foo foo.c

The new executable, foo, will be optimized to execute faster, and will not include any instrumentation library calls. Note the same optimization flags specified when creating the instrumented data file with the -fb-create must be specified when invoking the compiler with the -fb-opt option. Otherwise, the compiler will emit checksum errors. The default is -fb-opt disabled.

-fb-phase=0|1|2|3|4

Specifies the compilation phase when the collection of instrumentation data is to be performed. The values for option -fb-phase must be in the range of 0 to 4 and is used in conjuction with -fb-create. Note the value 0 indicates the initial phase, which is at the output of the preprocessor (i.e. after the front-end processing). The default is -fb-phase=0.

-finstrument-functions

Generates instrumentation calls for entry and exit to functions. Just after function entry and just before function exit, the following profiling functions will be called with the address of the current function and its call site. (On some platforms, __builtin_return_address does not work beyond the current function, so the call site information may not be available to the profiling functions otherwise.)

 void __cyg_profile_func_enter (void *this_fn,
  void *call_site);
 void __cyg_profile_func_exit (void *this_fn,
  void *call_site);

The first argument is the address of the start of the current function, which may be looked up exactly in the symbol table.

This instrumentation is also done for functions expanded inline in other functions. The profiling calls will indicate where, conceptually, the inline function is entered and exited. This means that addressable versions of such functions must be available. If all your uses of a function are expanded inline, this may mean an additional expansion of code size. If you use extern inline in your C code, an addressable version of such functions must be provided. (This is normally the case anyway, but if you get lucky and the optimizer always expands the functions inline, you might have gotten away without providing static copies.)

A function may be given the attribute no_instrument_function, in which case this instrumentation will not be done. This can be used, for example, for the profiling functions listed above, high-priority interrupt routines, and any functions from which the profiling functions cannot safely be called (perhaps signal handlers, if the profiling routines generate output or allocate memory).

Note specifying -finstrument-functions implies -OPT:cyg_instr=3, for more details See -OPT:cyg_intsr=3.

Next: General Optimizations, Previous: FDO Options, Up: Optimize Options

3.9.2 Options that Control Global Optimizations

-apo

Instructs the compiler to automatically transform sequential code into parallel code. The compiler will only transform blocks of code that will demonstrate a speed-up to the runtime (i.e. execute faster) on a multiprocessor target.

-O0|1|2|3|s

Optimize. Optimizing compilation takes somewhat more time, and a lot more memory for a large function.

-00: Instructs the compiler to not optimize.
-O1: With -O1, the compiler tries to reduce code size and execution time, without performing any optimizations that take a great deal of compilation time.
-O2: Optimize even more. The compiler performs nearly all supported optimizations that do not involve a space-speed tradeoff. The compiler does not perform loop unrolling or function inlining when you specify -O2. As compared to -O1, this option increases both compilation time and the performance of the generated code.
-O3: Optimize yet more. -O3 turns on all optimizations specified by -O2 and proceeds to take a more agressive approach. The compiler attempts to generate a high-quality code even at the expense of compile time. This level of optimization may specify optimization options that are generally beneficial but decisively cause performance degradations.
-Os: Optimize for size. -Os enables all -O2 optimizations that do not typically increase code size. It also performs further optimizations designed to reduce code size.

If you use multiple -O options, with or without level numbers, the last such option is the one that is effective. Level 2 is assumed if no value is specified (i.e. -O). The default is -O2.

-Ofast

Uses a selection of optimizations in order to maximize performance. Specifying -Ofast is equivalent to

 -O3 
 -ipa 
 -OPT:Ofast 
 -fno-math-errno 
 -ffast-math

These optimization options are generally safe. Floating-point accuracy may be affected due to the transformation of the computational code. Note that the interprocedural analysis option, -ipa, specifies limitations on how libraries and object files (.o files) are built.

-WOPT:question=answer

This group of options controls the effect the global optimizer has on the program. -WOPT: only influences global optimizations specified by -O2 or above.

-WOPT:aggstr=N

Option -WOPT:aggstr regulates the aggressiveness of the compiler's scalar optimizer when performing strength reduction optimizations. Strength reduction is the substitution of induction expressions within a loop with temporaries that are incremented together with the loop variable. The value N specifies the maximum number of induction expressions being replaced. Select positive integers only for variable N. Setting N=0 tells the scalar optimizer to use strength reduction for non-trivial induction expressions. Note specifying very aggressive strength reductions may prompt additional temporaries increasing register pressure and resulting in excessive register spills that decrease performance. The default is -WOPT:aggstr=11.

-WOPT:const_pre=ON|OFF

-WOPT:const_pre=ON instructs the compiler to perform the loading of registers using placement optimizations. The default is -WOPT:const_pre=ON.

-WOPT:if_conv=0|1|2

-WOPT:if_conv instructs the compiler to transform simple IF statements to conditional move instructions. -WOPT:if_conv has three settings:

0: Disables this optimization
1: Specifies conservative IF statement transformations. The context surrounding the IF statement is used in the transformation decision.
2: Use aggressive IF statement transformations. Perform the IF statement transformation regardless of the surrounding context.

The default is -WOPT:if_conv=1.

-WOPT:ivar_pre=ON|OFF

-WOPT:ivar_pre=ON instructs the compiler to use partial redundancy elimination of indirect loads in the program. The default is -WOPT:ivar_pre=ON.

-WOPT:mem_opnds=ON|OFF

The compiler's scalar optimizer is instructed to use automated reasoning to protect all memory operands of arithmetic operations. The process attempts to incorporate memory loads as part of the operands of arithmetic operations (e.g., the compiler tries to combine a memory load and an arithmetic instruction into one instruction). The default is WOPT:mem_opnds=OFF.

-WOPT:retype_expr=ON|OFF

Whenever possible the compiler calculate 64-bit addresses using 32-bit arithmetic. The default is -WOPT:retype_expr=OFF.

-WOPT:unroll=0|1|2

Specifying WOPT:unroll helps regulate the compiler's scalar optimizer when unrolling of innermost loops. The available settings are:

0: Innermost loop unrolling is suppressed.
1: Instructs the compiler's scalar optimizer to unroll the innermost loops which contain IF statements. Selecting this setting complements the loop unrolling performed in the code generator.
2: Instructs the compiler's scalar optimizer to unroll the innermost loops which contain straight line code plus the loops containing IF statements. Selecting this setting duplicates the unrolling performed in the code generator (i.e. unrolling straight line code in the body of a loop).

Note -WOPT:unroll and the unrolling options in the -OPT group are mutually exclusive. The default is -WOPT:unroll=1.

-WOPT:val=0|1|2

The compiler attempts to identify expressions which compute identical runtime values. Then proceeds to adjust the code to avoid recomputing the values. Setting -WOPT:val tells the global optimizer the number of times the value-numbering optimization should be performed. The default is -WOPT:val=1.

Next: IPO Options, Previous: Global Options, Up: Optimize Options

3.9.3 Options that Control General Optimizations

The options below control general optimizations that are not associated with a specific compilation phase.

The following options control specific optimizations. They are either activated by -O options or are related to ones that are. You can use the following flags in the rare cases when “fine-tuning” of optimizations to be performed is desired.

The following options control compiler behavior regarding floating point arithmetic. These options trade off between speed and precision. All must be specifically enabled.

-ffast-math

-fno-fast-math

Instructs the compiler to relax ANSI/ISO or IEEE rules/specifications for math functions in order to optimize floating-point computations to improve runtime. -fno-fast-math instructs the compiler to conform to ANSI and IEEE math rules.

This option causes the preprocessor macro __FAST_MATH__ to be defined.

Note:

 -Ofast implies -ffast-math.
 -ffast-math sets options -fno-math-errno and -OPT:IEEE_arithmetic=2.
 -fno-fast-math sets options -fmath-errno and -OPT:IEEE arithmetic=1.

-ffloat-store

Do not store floating-point variables in registers, and inhibit other options that might change whether a floating point value is taken from a register or memory.

This option prevents undesirable excess precision on the computations performed in the floating-point unit, regardless of the original type (e.g., registers keep more precision than a double is required to have). For most programs, the excess precision does only good, but a few programs rely on the precise definition of IEEE floating point. Use -ffloat-store for such programs, after modifying them to store all pertinent intermediate computations into variables. -ffloat-store generates stores to memory of all pertinent immediate computations to be truncated to a lower precision which may generate extra stores slowing down program execution. (See -mx87-precision, for more details). Note -ffloat-storehas no effect under -msse2, the default when specifying -m32 and -m64.

-fno-math-errno

Do not set ERRNO after calling math functions that are executed with a single instruction, e.g., sqrt. A program that relies on IEEE exceptions for math error handling may want to use this flag for speed while maintaining IEEE arithmetic compatibility. Note specifying -Ofast implies -fno-math-errno. The default is -fmath-errno.

-funsafe-math-optimizations

-fno-unsafe-math-optimizations

-funsafe-math-optimizations instructs the compiler to allow optimizations for floating-point arithmetic that assume that arguments and results are valid, and may violate IEEE or ANSI standards. When used at link-time, it may include libraries or startup files that change the default floating-point unit control word or other similar optimizations. -fno-unsafe-math-optimizations instructs the compiler to conform to ANSI and IEEE math rules. The default is -fno-unsafe-math-optimizations.

-mx87-precision=32|64|80

Specifies the floating-point precision of the floating-point units calculations. The three settings available are: 32-bit, 64-bit, or 80-bit. The default is -mx87-precision=80.

-noexpopt

Instructs the compiler to not optimize exponential operations.

-openmp

-mp

Instructs the compiler to interpret OpenMP directives to explicitly parallelize specified code for multi-thread execution on shared-memory multiprocessor models. The pathcc, pathCC, and pathf95 compilers support directives for OpenMP 2.4.

-OPT:question=answer

The -OPT: option group controls various optimizations. The -OPT: options supersede the defaults that are based on the main optimization level.

-OPT:alias=model

Identify which pointer aliasing model to use. The compiler will make assumptions during compilation when one or more of the following model is specified.

typed: Assumes that two pointers of different types will not point to the same location in memory (i.e. the code adheres to the ANSI/ISO C standards). Note when specifing -OPT:Ofast turns this option ON.
restrict: Assumes that distinct pointers are pointing to distinct non-overlapping objects. This optimization is disabled by default.
disjoint: Assumes that any two pointer expressions are pointing to distinct non-overlapping objects. This optimization is disabled by default.
no_f90_pointer_alias: Assumes that any two different Fortran 90 pointers are pointing to distinct non-overlapping objects. This optimization is disabled by default.

-OPT:align_unsafe=ON|OFF

Assumes that array parameters are aligned at 128-bit boundries and instructs the vectorizor to aggressively vectorize the code. The vectorizor then proceeds to generate 128-bit aligned load and store instructions. Note the aligned memory accesses will execute faster than unaligned accesses, but if the assumption is faulty the aligned memory accesses will result in runtime segmentation faults. The default is -OPT:align_unsafe=OFF.

-OPT:asm_memory=ON|OFF

Assumes each inline assembly instruction has specified memory (i.e. even if it is not available). Note this switch can be used to debug suspicious inline assembly code. The default is -OPT:asm_memory=OFF.

-OPT:bb=N

The value N limits the number of instructions a basic block can contain in the code generator's program representation. A basic block is defined as the straight line sequence of instructions with no control flow. Note the larger the value N the greater the opportunity exists for appling optimizations at the basic block level. Compiling programs where N is large and that exhibit large basic blocks could increase compilation time. The default is -OPT:bb=1300. Select a smaller value if compilation time becomes an issue.

-OPT:cis=ON|OFF

SIN/COS pairs that use identical arguments are converted to a single call and both values are calculated at once. The default is -OPT:cis=ON.

-OPT:cyg_instr=0|1|2|3|4

Instructs the compiler to insert instrumentation calls into each function. Instrumentation calls are inserted following the function entry and just before the function returns. Example insertions:

void__cyg_profile_func_entry (void *func_address, void *return_address);
 void__cyg_profile_func_exit (void *func_address, void *return_address);

Where, the first argument is the address at the start of the current function and the second argument is the return address into the caller of the current function.

-OPT:cyg_instr has five settings that control which functions are not instrumented:

0: Do not instrument any function.
1: Do not instrument functions the GNU front-end selects for inlining.
2: Do not instrument functions marked inline in the source.
3: Do not instrument functions marked extern inline or always_inline.
4: Instrument all functions and disable deletion of extern inline functions. Specifing this value may create linking and runtime faults.

Note options -finstrument-function and -OPT:cyg_instr=3 are equivalent, See -finstrument-functions.

For any function assigned the attribute no_instrument_function, instrumentation will be suppressed (e.g., do not instrument functions __cyg_profile_func_enter and __cyg_profile_func_exit).

-OPT:div_split=ON|OFF

Instruct the compiler to transform x/y into x*(recip(y)). Flags -OPT:Ofast or -OPT:IEEE_arithmetic=3 will enable this option. Note this transformation generates fairly accurate code. The default is -OPT:div_split=OFF.

-OPT:early_mp=ON|OFF

Instructs the compiler to transform code to execute under multiple threads only before or after the loop nest optimization (LNO) phase in the compilation process. When -OPT:early_mp=ON some OpenMP programs yield better perfomance because LNO is allowed to generate appropriate loop transformations when working on the multithreaded forms of loops. Note if -apo is specified the transformation of code executing multiple threads can only take place after LNO phase. In which case the -OPT:early_mp flag is ignored.

The default is -OPT:early_mp=OFF.

-OPT:early_intrinsics=ON|OFF

Generate calls to intrinsics which can be expanded to inline code early in the back-end compilation. The early inlining could expose short-vector forms in the expanded code leading to vectorization opportunities. The default is -OPT:early_intrinsics=OFF.

-OPT:fast_bit_intrinsics=ON|OFF (Fortran Only)

If -OPT:fast_bit_intrinsics=ON the check for the bit count being within range for Fortran intrinsics (e.g., BTEST or ISHFT) will be turned off. The default is -OPT:fast_bit_intrinsics=OFF.

-OPT:fast_complex=ON|OFF

Specifies fast calculations for values declared to be of the type complex. Fast algorithms are used for complex absolute value and complex division. The algorithm will overflow for an operand (e.g., the divisor in the case of division) that has an absolute value that is larger than the square root of the largest representable floating-point number. Also, the algorithm will underflow for a value that is smaller than the square root of the smallest representable floating point number. Note, specifying -OPT:roundoff=3 will also set -OPT:fast_complex=ON. The default is -OPT:fast_complex=OFF.

-OPT:fast_exp=ON|OFF

Transforms exponentiation by integers or halves to sequences of multiplies and square roots. This option can affect roundoff, and can make these functions produce minor discontinuities at the exponents where it applies. Note specifing -O3, -Ofast, or -OPT:roundoff=1 will enable this option. The default is -OPT:fast_exp=OFF.

-OPT:fast_io=ON|OFF (C/C++ Only)

Instruct the compiler to enable inlining of printf(), fprintf(), sprintf(), scanf(), fscanf(), sscanf(), and printw() for more specialized lower-level subroutines. The option invokes inlining only if the prospects are marked as intrinsic in the respective header files (i.e. <stdio.h> and <curses.h>) Note programs that use I/O functions (e.g., printf() or scanf() extensively generally have improved I/O performance when this flag is enabled. Use of this option may create substantial code expansion. The default is -OPT:fast_io=OFF.

-OPT:fast_math=ON|OFF

Instructs the compiler to use the fast math functions tuned for the target processor. The fast math functions include log, exp, sin, cos, sincos, expf, and pow. Note -OPT:fast_math=ON when -OPT:roundoff is set to be equal to or greater than 2. The default is -OPT:fast_math=OFF.

-OPT:fast_nint=ON|OFF

Instructs the compiler to use hardware features to implement single-precision and double-percision NINT and ANINT. Note if -OPT:roundoff=3 is specified then -OPT:fast_nint=ON. The default is -OPT:fast_nint=OFF.

-OPT:fast_sqrt=ON|OFF

Instructs the compiler to calculate the square root using the identity sqrt(x)= x*rsqrt(x) (where rsqrt equals the reciprocal square root operation). Fairly accurate code is generated when specifying this transformation. Note -OPT:fast_exp=ON must be specified which instructs the compiler to generate inlined instructions and not to call the library pow function before -OPT:fast_sqrt=ON can perform its transformation. -OPT:fast_sqrt has no dependencies on -OPT:rsqrt and unlike -OPT:rsqrt the transformation request by -OPT:fast_sqrt does not generate extra instructions when implementing rsqrt. The default is -OPT:fast_sqrt=OFF.

-OPT:fast_stdlib=ON|OFF

Instructs the compiler to generate calls to faster versions of standard library functions. The default is -OPT:fast_stdlib=ON.

-OPT:fast_trunc=ON|OFF

Instructs the compiler to inline the single-precision and double-precision versions of the Fortran intrinsics NINT, ANINT, and AMOD. Note -OPT:fast_trunc=ON is specified if -OPT:roundoff is equal to or greater than 1. The default is -OPT:fast_trunc=OFF.

-OPT:fold_reassociate=ON|OFF

When set to ON the compiler performs transformations which reassociate or distribute a floating-point expression. Note, specifying -O3 or -OPT:rounoff to be equal to or greater than 2, forces -OPT:fold_reassociate=ON . The default is -OPT:fold_reassociate=OFF.

-OPT:fold_unsafe_relops=ON|OFF

Instructs the compiler to fold relational operators that will transform possible integer overflow.

Note, specifying -O3 sets -OPT:fold_unsafe_relops=ON. The default is -OPT:fold_unsafe_relops=OFF.

-OPT:fold_unsigned_relops=ON|OFF

Instructs the compiler to fold unsigned relational operators that will transform possible integer overflow. The default is -OPT:fold_unsigned_relops=ON

-OPT:goto=ON|OFF

Transforms GOTO into higher level structures e.g., FOR loops. Note if -O2 is specified then -OPT:goto=ON. The default is -OPT:goto=OFF.

-OPT:IEEE_arithmetic=1|2|3

-OPT:IEEE_arith=1|2|3

-OPT:IEEE_a=1|2|3

This flag regulates the level of conformance to ANSI/IEEE 754-1985 floating point roundoff and overflow. Note -OPT:IEEE_arith and -OPT:IEEE_a are valid abbreviations for the option. The levels of conformance:

1: Adhere to IEEE 754 accuracy. Specifying -O0, -O1, and -O2 will set -OPT:IEEE_arithmetic=1.
2: Produces results that do not conform to IEEE 754. Specifying -O3 will set -OPT:IEEE_arithmetic=2.
3: All valid mathematical transformations are allowed.

-OPT:IEEE_NaN_inf=ON|OFF

Instructs the compiler to conform to ANSI/IEEE 754-1985 for all operations which produce a NaN or infinity result. Note NaN and infinity are typically handled as special cases in floating-point representations of real numbers and are defined by the IEEE 754 Standards for Binary Floating-point Arithmetic.

When setting this option to OFF, various operations that do not produce IEEE-754 results. For example, x/x is set to the value 1 without performing a divide operation and x=x is set to TRUE without executing a test operation. -OPT:IEEE_NaN_inf=OFF also specifies multiple optimizations that increase performance. The default is -OPT:IEEE_NaN_inf=OFF.

-OPT:inline_intrinsics=ON|OFF (Fortran Only)

-OPT:inline_intrinsics=OFF transforms all Fortran intrinsics that have a library function into a call to that function. The default is -OPT:inline_intrinsics=ON.

-OPT:keep_ext=ON|OFF

Instructs the compiler to preserve external symbolic information. The default is -OPT:keep_ext=OFF.

-OPT:malloc_algorithm=0|1

-OPT:malloc_alg=0|1

To improve runtime speed the compiler will select an optimal malloc algorithm. To enable the selected algorithm, setup code is included in the C/C++ and Fortran main function. The default is -OPT:malloc_algorithm=0

-OPT:Ofast

Maximizes performance for a given platfrom using the selected optimizations. -OPT:Ofast specifies four optimizations: -OPT:ro=2, -OPT:Olimit=0, -OPT:div_split=ON, and -OPT:alias=typed. Note the specified optimizations are ordinarily safe but floating point accuracy due to transformations may be diminished.

-OPT:Olimit=N

Controls the size of procedures to be optimized. Procedures above the specified cutoff limit, N, are not optimized. N=0 means ”infinite Olimit,” which causes all procedures to be optimized with no consideration regarding compilation times. Note if -OPT:Ofast is enabled then -OPT:Olimit=0 or when -O3 is enabled -OPT:Olimit=9000. The default is -OPT:Olimit=6000.

-OPT:pad_common=ON|OFF

Instructs the compiler to reorganize common blocks in order to optimize the cache behavior of accesses to members of the common block. To achieve the optimum, additional padding between members of blocks and/or dividing a common block into a group of blocks may be required. Note:

do not specify this option unless the common block definitions (i.e. including EQUIVALENCE) are consistent among all source codes making up a program.
do not specify -OPT:pad_common=ON if common blocks are initialized with DATA statements
Specifying -OPT:pad_common=ON implies that all source codes in the program conform to this transformation.

The default is -OPT:pad_common=OFF

-OPT:recip=ON|OFF

Instructs the compiler to use the reciprocal instruction for 1.0/y This may change the accuracy of the results. For example, X = 1./Y generates the reciprocal instruction instead of a divide instruction. The default is -OPT:recip=OFF.

-OPT:reorg_common=ON|OFF

Instructs the compiler to reorganize common block in order to optimize the cache behavior of accesses to members of the common block. If the compiler determines it is safe, it will proceed with the common block reorganization. Note defaults are:

-OPT:reorg_common=ON: When -O3 is specified, plus all source files which reference the common block are compiler with -O3.
_OPT:reorg_common=OFF: -O2 or below is specified when compiling the file that contains the common block.

-OPT:roundoff=0|1|2|3

-OPT:ro=0|1|2|3

-OPT:roundoff specifies acceptable levels of divergence for both accuracy and overflow/underflow behavior of floating-point results relative to the source language rules. The roundoff value has a value in the range 0 to 3 and are described in the following table:

0

Do no transformations which could affect floating-point results. The is the default for optimization levels -O0, -O1, and -O2.

1

Allow all transformations which have a limited affect on floating-point results. For roundoff, limited is defined as only the last bit or two of the mantissa is affected. For overflow or underflow, limited is defined as intermediate results of the transformed calculation may overflow or underflow within a factor of two where the original expression may have overflowed or underflowed. Note that effects may be less limited when compounded by multiple transformations. This is the default when -O3 is specified.

2

Specifies transformations with extensive effects on floating-point results. For example, allow associative rearrangement (i.e. even across loop iterations) and the distribution of multiplication over addition or subtraction. Do not specify transformations known to cause:

cumulative roundoff errors.
overflow/underflow of operands in a large range of valid floating-point values.

This is the default when specifying -OPT:Ofast

3

Specify any mathematically valid transformation of floating-point expressions. For example, floating point induction variables in loops are permitted (even if known to cause cumulative roundoff errors). Also permitted are fast algorithms for complex absolute value and divide (which will overflow/underflow for operands beyond the square root of the representable extremes).

-OPT:rsqrt=0|1|2

Instructs the compiler to use the reciprocal square root instruction when calculating the square root. This transformation may vary the accuracy slightly.

0: Restrain from using the reciprocal square root instruction
1: Use the reciprocal square root instruction followed by operations that will improve the accuracy of the results.
2: Use the reciprocal square root instruction without improving the result accuracy.

Note specifying -OPT:roudoff=2 or -OPT:roundoff=3 will set -OPT:rsqrt=1. The default is -OPT:rsqrt=0.

-OPT:space=ON|OFF

Instructs the compiler to consider code size as a higher priority then execution time when performing optimization. Note -Os sets this option to equal ON. The default is -OPT:space=OFF.

-OPT:speculate=ON|OFF

Instructs the compiler to make an effort to eliminate branches at the expense of increasing the computations. Whenever possible, the compiler transforms short-circuiting conditionals to comparable non-short-circuited structures. The default is -OPT:speculate=OFF.

-OPT:transform_to_memlib=ON|OFF

Instructs the compiler to perform loop transformations by using library function calls to memcpy or memset. The default is -OPT:transform_to_memlib=ON.

-OPT:treeheight=ON|OFF

Instructs the compiler to perform a global reassociation of expressions which reduces the tree height of the expressions. The reassociation process determines the optimum order of combining terms in a sum so as to produce loop invariant constant subcomputations or to refine common subexpressions amoung several essential computations. The default is -OPT:treeheight=OFF.

-OPT:unroll_analysis=ON|OFF

Instructs the compiler to disregard both -OPT:unroll_times_max and -OPT:unroll_size. The compiler then proceeds to perform a global analysis of the loop constructs to determine the optimum loop unrolling parameters. As a result of the analysis minimal loop unrolling which reduces code size may occur, permitting a faster compilation. Note specifying -OPT:unroll_analysis=ON negates the effects of -OPT:unroll_times_max and -OPT:unroll_size causing loops to be unrolled by less than the upper limit. The default is -OPT:unroll_analysis=ON.

-OPT:unroll_level=1|2

Controls the level at which the compiler will perform unrolling optimizations. When -OPT:unroll_level=2 the compiler is instructed to aggressively unroll loops in the presence of control flow. The default is -OPT:unroll_level=1.

-OPT:unroll_times_max=N

Instructs the compiler to limit the unrolling of inner loops to the value specified by N. The default is -OPT:unroll_times_max=4.

-OPT:unroll_size=N

Instructs the compiler to limit the number of instructions produced when unrolling inner loops. When N=0 the ceiling is disregarded. Note specifying -O3 sets -OPT:unroll_size=128. The default is -OPT:unroll_size=40.

-OPT:wrap_around_unsafe_opt=ON|OFF

-OPT:wrap_around_unsafe_opt=OFF instructs the compiler not to perform induction variable replacement and linear function test replacement. Both of these transformations are enabled when specifying -O3. The option is provided as a diagnostic tool. Note specifying -O0 sets -OPT:wrap_around_unsafe_opt=OFF. When -OPT:wrap_around_unsafe_opt=OFF the performance may be degraded.

Next: LNO Options, Previous: General Optimizations, Up: Optimize Options

3.9.4 Options that Control Interprocedural Optimizations

Inline expansion, or inlining, is a compiler optimization that replaces a function call with the body of the function. This optimization may improve time and space usage at runtime, at the possible cost of increasing the final code size.

-fimplicit-inline-templates (C++ Only)

-fno-implicit-inline-templates (C++ Only)

-fimplicit-inline-templates instructs the compiler to emit code for implicit instantiations of inline templates. -fno-implicit-inline-templates will never emit code for implicit instantiations of inline templates. The default is -fno-implicit-inline-templates.

-fimplicit-templates (C++ Only)

-fno-implicit-templates (C++ Only)

-fimplicit-templates instructs the compiler to emit code for non-inline templates which are instantiated implicity. -fno-implicit-templates will never emit code for non-inline templates which are instantiated implicitly (i.e. by use); it will only emit code for explicit instantiations.

-finline

-fno-inline

-inline

-INLINE

-noinline

Options -finline,-INLINE and -inline instruct the compiler to perform inline processing (i.e. expansion of inline functions). If optimizations are not being performed then function inlining is suppressed. -fno-inline and -noinline disable inlining and don't pay attention to the inline keyword. Note when performing interprocedural analysis (IPA) then -IPA:inline=OFF must be specified when disabling inlining.

-finline-functions (C/C++ Only)

-fno-inline-functions (C/C++ Only)

-finline-functions automatically integrates simple functions (i.e. the callees) into the callers. The compiler heuristically decides which functions are simple enough to be worth integrating in this way. If all calls to a given function are integrated, and the function is declared static, then normally assembler code is not generated for the function. Specifying -fno-inline-functions will disable the automatic integration of simple functions. Note this option is enabled at optimization level 3, -O3. The default is -fno-inline-function.

-fkeep-inline-functions (C/C++ Only)

Instructs the compiler to generate code for functions even if they are fully inlined. In C, emit code for static functions that are declared inline into the object file, even if the function has been inlined into all of its callers. This switch does not affect functions using the extern inline extension in C. In C++, emit any and all inline functions into the object file.

-INLINE:question=answer

This option group transforms function calls by use of inlining. If inlining directives are inserted in the source code then the -INLINE option must be specified in order for those directives to be recognized. Note when specifying the -INLINE option the program may not always compile successfully, with the exception of -INLINE:=OFF which suppresses the invocation of the lightweight inliner.

-INLINE:all: Instructs the compiler to perform all possible inlining. Note since inlining increases the code size, this option should be specified with some discretion (e.g., use only if program is small).
-INLINE:aggressive=ON|OFF: Instructs the compiler to be very aggressive when performing inlining. The default is -INLINE:aggressive=OFF.
-INLINE:list=ON|OFF: Instructs the compiler to emit a list of inlining transformations as they occur to stderr. The emitted comments outline which functions are inlined, which functions are not inlined, and why. The default is -INLINE:list=OFF.
-INLINE:must=name1[,name2,...]
-INLINE:never=name1[,name2,...]: Functions can be tagged for inlining by specifying the function name when using the -INLINE:must option or suppressed by using the option -INLINE:never. Note when using this option in C++, use the C++ mangled name for the function.
-INLINE:none: Disables automatic inlining specified by the interprocedural analysis group option (-IPA:). Note inlining specified by a command-line option or implied by the language are still performed. The default is automatic inlining is turned ON.
-INLINE:preempt=ON|OFF: Inline functions labeled preemptible in the lightweight inliner. Preempt inlining prevents alternate definitions of a function, in another dynamic shared object (DSO), from preempting the definition of the function being inlined. The default is -INLINE:preempt=OFF.

-ipa

-IPA

-IPA:

Instructs the compiler to invoke interprocedural analysis. These options are identical. The default settings for the -IPA:question=answer option group are invoked. Specifying -ipa is equivalent to -IPA and -IPA: with no suboptions.

-IPA:question=answer

The -IPA: option group commands the compiler to perform interprocedural analysis and optimization. Interprocedural analysis and optimization can include: inlining, common block array padding, constant propagation, dead function elimination, alias analysis, and others. If the option group defaults are acceptable for compilation then -IPA: can be specified without specifing arguments. Note if compiling and linking are performed in separate steps then -IPA: must be specified for compilation step and for the link step. An error will occur if -IPA: is specified for the compile step and not for the link step.

-IPA:addressing=ON|OFF

Enabling this option invokes the analysis of address operator usage. Setting -IPA:alias=ON is a prerequisite for this option. The default is -IPA:addressing=OFF.

-IPA:aggr_cprop=ON|OFF

The compiler is instructed to perform aggressive interprocedural constant propagation. Interprocedural constant propagation is a process which replaces formal parameters by their corresponding constant values. This process strives to prevent passing constant parameters. The conventional interprocedural constant propagation (-IPA:cprop=ON) is performed by default. The default is -IPA:aggr_cprop=OFF.

-IPA:alias=ON|OFF

The compiler is instructed to perform ALIAS, MOD, and REF analysis. -IPA:alias=ON specifies an interprocedural analysis that provides results not affected by control flow in procedures. The default is -IPA:alias=ON.

-IPA:callee_limit=N

The compiler is instructed not to allow inlining of functions with a compiler-evaluated internal code size larger than the limit set by N. The default is -IPA:callee_limit=500.

-IPA:cgi=ON|OFF

The compiler is instructed to identify constant global variables. The compiler tags all non-scalar global variables which are not modified as constants, and never passes their constant values to all programs. The default is -IPA:cgi=ON.

-IPA:clone_list=ON|OFF

The compiler is instructed to use the interprocedural analysis function cloner to list all cloning actions performed by the compiler to stderr. The default is -IPA:clone_list=OFF.

-IPA:common_pad_size=N

The compiler is instructed to pad common block array dimensions by the value N. By default, the compiler automatically chooses the amount of padding to improve cache behavior for common block array accesses. The default is -IPA:common_pad_size=0.

-IPA:cprop=ON|OFF

The compiler is instructed to perform interprocedural constant propagation. Interprocedural constant propagation is a process which replaces formal parameters that always have a specific constant values. The default is -IPA:cprop=ON.

-IPA:ctype=ON|OFF

Instructs the compiler to generate accelerated versions of the <ctype.h> header macros (e.g., isalpha(), isascii(),...). Note using this option when compiling multithreaded code and in all locales (i.e. other than the 7-bit ASCII or C-language locale) may generate unstable executables. The default is -IPA:ctype=OFF

-IPA:depth=N

-IPA:depth=N is equivalent to -IPA:maxdepth=N.

-IPA:dfe=ON|OFF

The compiler is instructed to perform ”dead function elimination” (dfe). The compiler removes all subprograms/functions which are never called from the program. Note when a function call is replaced by inlining the function everywhere in the program then the original function becomes a ”dead function” and is eliminated. The default is -IPA:dfe=ON.

-IPA:dve=ON|OFF

The compiler is instructed to perform ”dead variable elimination” (dve). The compiler removes all variables which are never referenced by the program. The default is -IPA:dve=ON.

-IPA:echo=ON|OFF

Instructs the compiler to echo the compiler and final link commands which are invoked from IPA to stderr. -IPA:echo=ON can assist in monitoring the progress of a large class program build. The default is -IPA:echo=OFF.

-IPA:field_reorder=ON|OFF

The compiler is instructed to reorder fields in large structures based on the fields reference patterns in feedback compilation. The field reordering minimizes data cache misses. The default is -IPA:field_reorder=OFF.

-IPA:forcedepth=N

When attempting to inline functions, the compiler is instructed to limit the depth in the callgraph to N. Note depth 0 refers to functions making no calls, depth 1 are those calling only depth 0 functions, and so on. By default -IPA:forcedepth is ignored and the heuristic limits on inlining are in effect.

-IPA:ignore_lang=ON|OFF

When performing inlining, the compiler is instructed to ignore language boundaries (i.e. inlining across the Fortran language to C/C++ language boundary). Note the compiler may not always be cognizant of the proper language semantics and this optimization may have effects at runtime producing unreliable or improper conclusions. The default is -IPA:ignore_lang=OFF.

-IPA:inline=ON|OFF

The compiler is instructed to perform inter-file subprogram inlining during main interprocedural analysis processing. The default is -IPA:inline=ON.

-IPA:keeplight=ON|OFF

Specifying the flag -keeplight instructs the compiler to save space. The default is -IPA:keeplight=OFF.

-IPA:linear=ON|OFF

The compiler is instructed to perform linearization of array references. The compiler transforms a multi-dimensional array to a linear array (i.e. single dimensional)which is mapped to the same memory block. The compiler attempts to map formal array parameters to the shape of the actual parameter when inlining Fortran subroutines. This mapping process may not always be successful, therefore when the compiler is unable to map the parameter it linearizes the array reference. Note the compiler will not attempt to inline such callsites due to possible performance problems. The default is -IPA:linear=OFF.

-IPA:map_limit=N

The interprocedural analysis process uses N as a threshold to trigger invoking -IPA:sp_partition. When the size of the input files mapped exceeds the limit, N bytes, the compiler enables -IPA:sp_partition. The default is -IPA:map_limit is ignored.

-IPA:maxdepth=N

The compiler is instructed to not attempt to inline functions at a depth in the callgraph which exceeds N. Note depth 0 refers to functions making no calls, depth 1 are those calling only depth 0 functions, and so on. By default -IPA:maxdepth is ignored and the heuristic limits on inlining are in effect.

-IPA:max_jobs=N

The compiler is instructed to limit the number of compilation running at once to N. After interprocedural analysis is performed the compiler is invoked with -IPA:max_job set to the maximum level of parallelism. N can be set to:

0

The maximum level of parallelism is limited to the greatest number of:

CPUs (or processor sockets),
processor cores,
or hyperthreading units

in the system.

1

Suppress parallelization during compilation.

>=2

Sets the desired level of parallelism

The default is -IPA:max_jobs=1.

-IPA:min_hotness=N

The compiler is instructed not to inline a function to a call site (i.e. caller) unless the callee is invoked more than N times. The compiler examines the interprocedural feedback to determine if the threshold set by N is surpassed by a call site to a procedure and then proceeds to inline the procedure if the limit is exceeded. The default is -IPA:min_hotness=10.

-IPA:multi_clone=N

Specifies to the compiler the maximum number of clones of a single procedure the compiler can create. Setting N to a large number promotes more opportunities for interprocedural optimizations. Note significant increase in code size may occur if aggressive procedural cloning is performed. The default is -IPA:multi_clone=0.

-IPA:node_bloat=N

When the compiler is invoked with option -IPA:multi_clone, -IPA:node_bloat can be specified to gage the code size growth due to procedural cloning. N specifies the maximum percentage of code size growth (i.e. relative to the orignal code size) due to the total number of procedures cloned. The default is -IPA:node_bloat=100.

-IPA:plimit=N

The compiler is instructed to halt inlining within a program once the intermediate representation indicates that the code size of the program has surpassed the limit set by N. The default is -IPA:plimit=2500.

-IPA:pu_reorder=0|1|2

The compiler is instructed to examine compilation feedback for invocation patterns to determine the process of reordering the layout of program procedures in order to minimize instruction cache misses. Possible settings are:

0: Suppress reordering of program procedures.
1: Use the frequent occurrence of procedure invocation to determine reordering.
2: Use the relationship between caller and callee to determine reordering.

The default is -IPA:pu_reorder=1 for C++ programs and -IPA:pu_reorder=0 for programs not written using C++.

-IPA:relopt=ON|OFF

The compiler is instructed to build objects under the presumption that the compiled objects will be linked into a call-shared executable. This optimization is modeled on performing position-dependent code on the compiled objects. Note -IPA:relopt is similar to invoking the compiler using -O and -c. The default is -IPA:relopt=OFF.

-IPA:small_pu=N

The compiler is instructed not to restrict a procedure from inlining with a code size smaller than N when invoking the -IPA:plimit flag. The default is -IPA:small_pu=30.

-IPA:sp_partition=ON|OFF

The compiler is instructed to use partitioning when building huge programs. Note partitioning is normally performed internal to the IPA. This option is invoked to conserve disk and memory space. The default is -IPA:sp_partition=OFF

-IPA:space=N

The compiler is instructed to perform inlining until the program code size expands by percentage specified by N. Therefore, to limit program code size growth to ~20%, due to inlining, specify -IPA:space=20. The default is -IPA:space=infinity.

-IPA:specfile=filename

When invoking the compiler with option IPA:specfile, the user indicates that a file, filename, containing additional options exist. The specified file must contain zero or more lines with the additional options in the proper command line syntax. Note the nesting of -IPA:specfile is not permitted.

-IPA:use_intrinsic=ON|OFF

The compiler is instructed to load the intrinsic version of standard library functions. Note -IPA:use_intrinsic may promote the inlining of the malloc library function. This option improves small object allocations. The default is -IPA:use_intrinsic=OFF.

Previous: IPO Options, Up: Optimize Options

3.9.5 Options that Control Loop Nest Optimizations

-LNO:question=answer

This option group commands the compiler loop nest optimizer to perform nested loop analysis and transformations. Note an optimization level of -O3 or higher must be specified in order to enable the -LNO:options.

To verify the LNO options that were invoked during compilation use the option -LIST:all_options=ON.

-LNO:apo_use_feedback=ON|OFF

Instructs the auto-parallelizer to use the feedback data of the loops in deciding if each loop should be parallelized. This option will only be invoked if -apo under feedback-directed compilation has been enabled. The compiler creates a serial and parallel version of a parallelized loop and if the loop trip count is small the serial version is used during execution. When -LNO:apo_use_feedback=ON and the feedback data validates that the loop trip count is small the auto-parallelizer will not create the parallel version (i.e. optimizing the runtime by eliminating the conditional code required to determine the use of the serial or parallel version). The default is -LNO:apo_use_feedback=OFF.

-LNO:build_scalar_reductions=ON|OFF

The compiler is instructed to build scalar reductions before performing any loop transformation analysis and implementing any loop reduction transformations. Note when -OPT:roundoff=2 or greater is specified then this flag is repetitious. The default is -LNO:build_scalar_reductions=OFF.

-LNO:blocking=ON|OFF

Instructs the compiler to perform cache blocking transformation. The default is -LNO:blocking=ON

-LNO:blocking_size=N

Instructs the compiler to use the specified block size, N, when performing all blocking. Note N represents the number of iterations and must be a positive integer.

-LNO:fission=0|1|2

Instructs the compiler to perform loop fission. This option can be set to:

0: Suppress loop fission.
1: The compiler performs normal loop fission as necessary.
2: The compiler performs loop fission prior to loop fusion.

Note loop fusion is usually applied before loop fission, therefore if -LNO:fission=ON and -LNO:fusion=ON when the compiler is invoked a reverse effect may be induced. To counter this effect specify -LNO:fission=2 to instruct the compiler to perform loop fission prior to loop fusion. The default is -LNO:fission=0.

-LNO:full_unroll=N

-LNO:fu=N

The compiler is instructed to fully unroll loops after examining the loop, within the loop nest optimizer, to determine if the loop can be fully unrolled in N or less iterations. Argument fu=N specifies the maximum number of unrolls that can be performed to fully unroll the loop. Note setting N=0 suppresses full unrolling of loops inside the loop nest optimizer. -LNO:fu is the abbreviated form for -LNO:full_unroll. The default is -LNO:full_unroll=5

-LNO:full_unroll_size=N

The compiler is instructed to fully unroll loops after examining the loop, within the loop nest optimizer, to determine if the unrolled loop size is less than or epual to N. Specify N as an interger between 0 and 10000. Note limits set by -LNO:full_unroll=N and -LNO:full_unroll_size=N must be satisfied before the loop is fully unrolled. The default is -LNO:full_unroll_size=2000

-LNO:full_unroll_outer=ON|OFF

The compiler is instructed to “fully” unroll loops that do not include inner loops or is included by an outer loop. Note limits set by both -LNO:full_unroll=N and -LNO:full_unroll_size=N must be satisfied before the loop is fully unrolled. The default is -LNO:full_unroll_outer=OFF

-LNO:fusion=0|1|2

The compiler is instructed to perform loop fusion. The flag can be set to:

0: Suppress loop fusion.
1: The compiler performs traditional loop fusion
2: The compiler performs agressive loop fusion

The default is -LNO:fusion=1.

-LNO:fusion_peeling_limit=N

The compiler is instructed to implement loop peeling during loop fusion. N sets the limit on the number of loop peeling iterations. Note N must be greater than or equal to zero. The default is -LNO:fusion_peeling_limit=5.

-LNO:gather_scatter=0|1|2

Instructs the compiler to perform gather-scatter optimizations. The flag can be set to:

0: Suppress gather-scatter optimizations.
1: The compiler performs gather-scatter optimizations to non-nested IF statements.
2: The compiler performs multi-level gather-scatter optimizations.

The default is -LNO:gather_scatter=1.

-LNO:hoistif=ON|OFF

The compiler is instructed to hoist IF statements which reside inside inner loops. This optimization will eliminate redundant loops. The default is -LNO:hoistif=ON.

-LNO:ignore_feedback=ON|OFF

The compiler is instructed to ignore feedback information generated by loop annotations during loop nest optimizations. The default is -LNO:ignore_feedback=OFF.

-LNO:ignore_pragmas=ON|OFF

Instructs the compiler to use command-line options instead of the corresponding directives in the source code. The default is -LNO:ignore_pragmas=OFF.

-LNO:local_pad_size=N

The compiler is instructed to pad local array dimensions by the amount specified in N. The default is to instruct the compiler to choose the padding required to optimize cache behavior for local array access.

-LNO:minvariant=ON|OFF

-LNO:minvar=ON|OFF

The compiler is instructed to move loop-invariant expressions outside of loops. -LNO:minvar is the abbreviated form for -LNO:minvariant. The default is -LNO:minvariant=ON

-LNO:non_blocking_loads=ON|OFF (C/C++ Only)

Instructs the compiler that the target processor blocks on loads. The default is specified by the host processor in use.

-LNO:oinvar=ON|OFF

The compiler is instructed to perform outer loop invariant hoisting. The default is -LNO:oinvar=ON

-LNO:opt=0|1

Instructs the compiler at which level to perform loop nest optimizations. The flag can be set to:

0: The compiler is restricted by suppress nearly all loop nest optimizations.
1: The compiler performs full loop nest optimizations.

The default is -LNO:opt=1

-LNO:ou_prod_max=N

The compiler is instructed to unroll several outer loops of a given loop nest. The product is limited to N outer loops. Note specify N as a positive number. The default is -LNO:ou_prod_max=16.

-LNO:outer=ON|OFF

The compiler is instructed to perform outer loop fusion. The default is -LNO:outer=ON.

-LNO:outer_unroll_max=N

-LNO:ou_max=N

The compiler is instructed to perform the unrolling of outer loops of a loop nest. The unrolling of the outer loop is limited to N unrolls per outer loop. -LNO:ou_max is the abbreviated form for -LNO:outer_unroll_max. The default is -LNO:outer_unroll_max=5.

-LNO:parallel_overhead=N

Specifying the auto-parallelizing option, -apo, instructs the compiler to generate a serial and parallel instance of a loop. Specifying -LNO:parallel_overhead in conjunction with -apo instructs the compiler to estimate the overhead involved when invoking the parallel instance of the loop taking into account the number of processors and loop iterations. The loop nest optimizer then uses N to determine if the overhead exceeds the performance benefit during execution time. Note using this flag with auto-parallelizer can be used to tune parallel performance across various platforms and programs. The default is -LNO:parallel_overhead=4096.

-LNO:prefetch=0|1|2|3

Instructs the compiler to perform prefetching optimizations at a specified level. The flag can be set to:

0: Instructs the compiler to suppress prefetching.
1: The compiler is instructed to allow prefetching only for arrays that are always referenced in every loop iteration.
2: The compiler is instructed to implement prefetching disregarding the restrictions in the above setting.
3: The compiler is instructed to implement agressive prefetching.

The default is -LNO:prefetch=2.

-LNO:prefetch_ahead=N

The compiler is instructed to prefetch ahead N cache line(s). The default is -LNO:prefetch_ahead=2.

-LNO:prefetch_verbose=ON|OFF

Instructs the compiler to print verbose prefetch information to stdout. The default is -LNO:prefetch_verbose=OFF.

-LNO:processors=N

-LNO:processors is used in conjunction with -apo and instructs the compiler to assume that the generated code will be executed on a given number of processors installed on the target system. Specifying this flag assists in decreasing the computation time during execution when determining which loop instance to execute (i.e. serial or parallel). See -LNO:parallel_overhead flag. Setting N=0 indicates the code should be compiled for a unknown number of processors and should be used when compiling programs that will be executed on platforms with different number of processors. Note the parallelized code will not perform optimally if N is set to a number that is different from the number of processors available in the target system. The default is -LNO:processors=0.

-LNO:sclrze=ON|OFF

The compiler is instructed to substitute a scalar variable for an array. The default is -LNO:sclrze=ON.

-LNO:simd=0|1|2

The compiler is instructed to use single instruction multiple data (SIMD) instructions, supported by the target processor, when vectorizing the inner loop. The flag can be set to:

0: The compiler is instructed to suppress vectorization.
1: The compiler is instructed to vectorize only if there is no performance degradation due to sub-optimal alignment and does not induce floating-point operation inaccuracies.
2: Instructs the compiler to aggressively vectorize with no contraints in place.

The default is LNO:simd=1.

-LNO:simd_reduction=ON|OFF

The compiler is instructed to vectorize reduction loops. The default is -LNO:simd_reduction=ON.

-LNO:simd_verbose=ON|OFF

Instructs the compiler to print verbose vectorizer information to stdout. The default is -LNO:simd_verbose=OFF.

-LNO:svr_phase1=ON|OFF

Instructs the compiler to implement the scalar variable naming phase prior to the first phase of the loop nest optimizer. The default is -LNO:svr_phase1=ON.

-LNO:trip_count_assumed_when_unknown=N

-LNO:trip_count=N

The compiler is instructed to use the value N as a presumed loop trip-count if at compile time a loop trip-count is not known. The loop trip-count, N, is used for loop transformations and prefetch optimizations and must be a positive integer. Note -LNO:trip_count is the abbreviated form. The default is -LNO:trip_count=1000.

-LNO:vintr=0|1|2

The compiler is instructed to use vector intrinsic functions when vectorizing loops. Where a vector function is called once to compute a math intrinsic for the entire vector. The flag can be set to:

0: Instructs the compiler to suppress vector intrinsic function optimizations.
1: The compiler is instructed to perform normal vector intrinsic function optimizations.
2: The compiler is instructed to aggressively implement all vector intrinsic function optimizations. Note specifying this option could cause some of the vector intrinsic functions to produce floating-point accuracy errors.

The default is -LNO:vintr=1.

-LNO:vintr_verbose=ON|OFF

Instructs the compiler to print verbose vector intrinsic optimization status to stdout. The status report will list loops that are vectorized using vector intrinsic functions. The default is -LNO:vintr_verbose=OFF.

The following Loop Transformation Suboptions allow the user to control cache blocking, loop unrolling, and loop interchange.

-LNO:interchange=ON|OFF: The compiler is instructed to perform loop interchange optimizations. The default is -LNO:interchange=ON.
-LNO:unswitch=ON|OFF: The compiler is instructed to perform simple loop unswitching transformations. The default is -LNO:unswitch=ON.
-LNO:unswitch_verbose=ON|OFF: Instructs the compiler to print verbose loop unswitching report to stdout. The default is -LNO:unswitch_verbose=OFF.
-LNO:outer_unroll=N
-LNO:ou=N: The compiler is instructed to unroll all outer loops by N iterations, i.e. when valid. The loop unrolling process is performed for N interations or is not performed at all. -LNO:ou is the abbreviated form for -LNO:outer_unroll. N must be a positive integer.
-LNO:outer_unroll_deep=ON|OFF
-LNO:ou_deep=ON|OFF: The compiler is instructed to unroll the outer wind down loops which is a result of unrolling outer loops further-out. This transformation is valid for loops nested three or more deep. Note this optimization generates faster runtime code, but increase code size. Option -LNO:ou_deep is the abbreviated form. The default is -LNO:outer_unroll_deep=ON.
-LNO:outer_unroll_further=N
-LNO:ou_further=N: The compiler is instructed to perform outer loop unrolling on wind down loops. The value N sets a limit on the number of iterations for unrolling wind down loops. Set N to a positive integer. Note: Specifying -LNO:outer_unroll_further=999999 suppress unrolling. Specifying -LNO:outer_unroll_further=3 sets a rational limit to unrolling.
Option -LNO:ou_further is the abbreviated form. The default is ou_further=6.
-LNO:outer_unroll_max=N
-LNO:ou_max=N: The compiler is instructed to unroll a limit of N copies-per-loop. Option -LNO:ou_max is the abbreviated form.
-LNO:pwr2=ON|OFF (C/C++ Only): When -LNO:pwr2=OFF the compiler is instructed to disregard the leading dimension. The default is -LNO:pwr2=ON.

The following LNO Target Cache Memory Suboptions allows the user to specify the target cache/memory system. The suboption arguments are numbered starting with the cache closest to the processor and progresses outward.

-LNO:assoc1=N, assoc2=N, assoc3=N, assoc4=N

Instructs the compiler to set cache associativity. Setting N to a large number, e.g. 128, specifies a fully associative cache (e.g., main memory). Note specify N as a positive integer. Setting N=0 specifies that no cache exist at that level.

-LNO:cmpl=N, cmp2=N, cmp3=N, cmp4=N, dmp1=N, dmp2=N, dmp3=N, dmp4=N

The compiler is instructed to set the time to process a clean miss (e.g. cmpx=N) or a dirty miss (e.g. dmpx=N) to the next level of the memory hierarchy. The value in N is representative of processor cycles and is approximate due to its dependency on a clean or dirty line, read or write miss, etc. Note specify N as a positive integer. Setting N=0 specifies that no cache exist at that level.

-LNO:cs1=N. cs2=N, cs3=N, cs4=N

The compiler is instructed to set the cache sizes. The value in N must include a suffix letter of k or K to indicate Kbytes or m or M to indicate Mbytes. Note specify N as a positive integer. Setting N=0 specifies that no cache exist at that level.

Note:

primary cache is represented by cs1
secondary cache is represented by cs2
memory is represented by cs3
disk is represented by cs4

Invoking the compiler with -LIST:all_options=ON will emit the default cache sizes of the host system being used for compilation. Cache sizes for each level of cache and memory are system dependent. The default is N=0 for each level of cache.

-LNO:is_mem1=ON|OFF, is_mem2=ON|OFF, is_mem3=ON|OFF, is_mem4=ON|OFF

The compiler is instructed to setup the memory model hierarchy as cache or memory.

An attempt to perform loop blocking is permitted once the memory model has been structured. Note specify loop blocking suitable for memory and not for cache. No prefetching is performed and all prefetching options are disregarded.

Note LNO suboption -LNO:is_memx=ON|OFF supersedes the corresponding suboptions -LNO:assocx=N and -LNO:cmpx=N,...., dmpx=N.

-LNO:ls1=N, ls2=N, ls3=N, ls4=N

The compiler is instructed to set the cache line sizes. The value in N is the number of bytes in a cache line. The size of the cache line dictates the number of bytes moved from one memory hierarchy on a miss at this level to another memory hierarchy level. Note specify N as a positive integer. Setting N=0 specifies that no cache exist at that level.

The following LNO Translation Lookaside Buffer Suboptions allows the user to specify the translation lookaside buffer (TLB) chacteristics. The suboption arguments are specified under the assumption that the cache for the page table is fully associative.

-LNO:ps1=N, ps2=N, ps3=N, ps4=N: The compiler is instructed to set the page table size. The value in N is the number of bytes in the page. Note specify N as a positive integer. The default for N is dependent on the target system hardware.
-LNO:tlb1=N, tlb2=N, tlb3=N, tlb4=N: The compiler is instructed to set the number of entries, N, in the TLB for a selected memory hierarchy level. Note specify N as a positive integer. The default for N is dependent on the target system hardware.
-LNO:tlbcmp1=N, tlbcmp2=N, tlbcmp3=N, tlbcmp4=N, tlbdmp1=N, tlbdmp2=N, tlbdmp3=N, tlbdmp4=N: The compiler is instructed to set the time to service a clean TLB miss (e.g. tlbcmpx=N) or a dirty TLB miss (e.g. dmpx=N) to the next level of the memory hierarchy. The value in N is representative of processor cycles and is approximate. Note specify N as a positive integer. The default for N is dependent on the target system hardware.

The following LNO Prefetch Suboptions allows the user to specify prefetch operations.

-LNO:assume_unknown_trip_count=N

This suboption is no longer supported by the compiler. Use -LNO:trip_count_assumed_when_unknown instead.

-LNO:pf1=ON|OFF, pf2=ON|OFF, pf3=ON|OFF, pf4=ON|OFF

The compiler is instructed to turn ON/OFF prefetching for specified cache levels.

-LNO:prefetch=0|1|2|3

The compiler is instructed to set the prefetching level. The flag can be set to:

0: Instructs the compiler to suppress prefetching.
1: Instructs the compiler to set prefetching only for arrays that are referenced in every loop iteration.
2: Instructs the compiler to turn prefetching ON disregarding the above restriction.
3: Instructs the compiler to perform aggressive prefetching.

The defaulti is -LNO:prefetch=2

-LNO:prefetch_ahead=N

The compiler is instructed to prefetch a set number, N, of cache lines ahead of the reference. Note specify N as a positive number. The default is -LNO:prefetch_ahead=2.

-LNO:prefetch_manual=ON|OFF

The compiler is instructed to allow directives specifying manual prefetches. If -LNO:prefetch_manual=OFF the directives are ignored. The default is -LNO:prefetch_manual=ON.

Next: Assembler Options, Previous: Optimize Options, Up: Invoking Path64

3.10 Options Controlling the Preprocessor

These options control the C preprocessor, which is run on each C source file before actual compilation.

If you specify the -E option nothing is done except preprocessing. See option -E, in Option Controlling the Kind of Output section. Some of these options make sense only together with -E because they cause the preprocessor output to be unsuitable for actual compilation.

-A predicate=answer

-A -predicate=answer

Make an assertion with the predicate predicate and answer answer. Option -A -predicate=answer cancels an assertion with the predicate predicate and answer answer.

-C (C Only)

Do not discard comments after preprocessing. All comments are passed through to the output file, except for comments in processed directives, which are deleted along with the directive.

The user will note the following side effects when using -C; it causes the preprocessor to treat comments as tokens in their own right. For example, comments appearing at the start of what would be a directive line have the effect of turning that line into an ordinary source line, since the first token on the line is no longer a #.

-cpp

Instructs the compiler to pass all input source code through the GCC preprocessor (i.e. the C preprocessor, cpp) before compiling, regardless of the filename suffix.

Note options -ftpp, -E, and -nocpp provide additional control of preprocessing. The -macro-expand option can be specified to enable macro expansion.

The default is the pass input files with suffix .F or .F90 through the C preprocessor (i.e. cpp). Preprocessing is not performed on files that have suffixes .f or .f90.

-dCHAR

The compiler is instructed to generate and write a specified list to the standard output file. Note CHAR is a sequence of one or more of the following characters, and must not be preceded by a space. Other characters are interpreted by the compiler proper, or reserved for future versions of Path64, and so are silently ignored. If you specify characters whose behavior conflicts, the result is undefined.

-dD: Generate a list of non-predefined macro directives.
-dI: Output #include directives in addition to preprocessor results.
-dM: Generate a list of directives for all macros.
-dN: Generate a list of all macro names defined.

-Dname

Predefine name as a macro, with definition 1. The name must be declared as a logical constant in the source files and will be set to true.

-Dname=definition

-Dvar=definition[,var=definition,...]

The contents of definition are tokenized and processed as if they appeared during translation phase three in a #define directive. In particular, the definition will be truncated by embedded newline characters. The preprocessor assigns values to the constants preempting values assigned within the source files. When the option contains an ”=” sign the value on the right must be an integer and the name on the left must de declared as an integer constant in the source files.

Note if the definition (i.e. def) is not specified a 1 is used. See -Uname, for information on undefined variables. -D and -U options are processed in the order they are given on the command line.

If you are invoking the preprocessor from a shell or shell-like program you may need to use the shell's quoting syntax to protect characters such as spaces that have a meaning in the shell syntax.

If you wish to define a function-like macro on the command line, write its argument list with surrounding parentheses before the equals sign (if any). Parentheses are meaningful to most shells, so you will need to quote the option. For example, with sh and csh, -D'name(args...)=definition'.

-fcoco=filename (Fortran Only)

For Fortran source files, run the ISO/IEC 1539-3 conditional compilation preprocessor before compiling. Option -fcoco takes precedence over the default (i.e. files with suffixes .F, .F90, or .F95 are preprocessed with cpp and files with suffixes .f, .f90 or .f95 are not preprocessed). If the filename is not specified, the preprocessor looks for coco.set in the current working directory.

â€“I flags are passed to the preprocessor and take precedence over the setfile. â€“D flags are passed to the preprocessor to assign values to constants and take precedence over values assigned within the source files. If the option is of the form -Dname=definition, the definition on the right side must be an integer, and the name on the left side must be declared as an integer constant within the source files. Otherwise, the name must be declared as a logical constant within the source files, and will be set true. Constants defined by -D should not be defined in the filename.

-fe

Instruct the compiler to halt after the prepreocessor is run (i.e. the compiler front-end).

-fpreprocessed (C/C++ Only)

-fno-preprocessed (C/C++ Only)

Instructs the compiler that the input source file has been preprocessed. -fno-preprocessed specifies that the input source file has not been preprocessed.

-ftpp (Fortran Only)

Fortran source files are processed by the Fortran source preprocessor before compiling.

By default, only files with suffix .F, .F90, or .F95 are processed by the C source preprocessor, cpp. Source files with suffix .f, .f90, or .f95 are not processed by the preprocessor

-M

Instead of outputting the result of preprocessing, output a rule suitable for make describing the dependencies of the main source file. The preprocessor outputs one make rule containing the object file name for that source file, a colon, and the names of all the included files, including those coming from -include or -imacros command line options.

Unless specified explicitly (with -MT or -MQ), the object file name consists of the basename of the source file with any suffix replaced with object file suffix. If there are many included files then the rule is split into several lines using \-newline. The rule has no commands.

To avoid mixing such debug output with the dependency rules you should explicitly specify the dependency output file with -MF, or use an environment variable like DEPENDENCIES_OUTPUT. Debug output will still be sent to the regular output stream as normal.

Passing -M to the driver implies -E, and suppresses warnings with an implicit -w.

-macro-expand (Fortran Only)

The preprocessor performs macro expansion throughout each Fortran source file. When option is not specified macro expansion is limited to preprocessor # directives only.

-MD

-MD is equivalent to -M -MF file, except that -E is not implied. The driver determines file based on whether an -o option is given. If it is, the driver uses its argument but with a suffix of .d, otherwise it takes the basename of the input file and applies a .d suffix.

If -MD is used in conjunction with -E, any -o switch is understood to specify the dependency output file (see -MF), but if used without -E, each -o is understood to specify a target object file.

Since -E is not implied, -MD can be used to generate a dependency output file as a side-effect of the compilation process.

-MDtarget filename (Fortran Only)

Use filename as the target for makefile dependencies. Used in conjunction with the option -MDupdate.

-MDupdate filename (Fortran and C Only)

Updates makefile dependencies in filename.

-MF filename

When used with -M or -MM, specifies a filename to write the dependencies to. If no -MF switch is given the preprocessor sends the rules to the same place it would have sent preprocessed output.

When used with the driver options -MD or -MMD, -MF overrides the default dependency output file.

-MG

In conjunction with an option such as -M or -MM requesting dependency generation, -MG assumes missing header files are generated files and adds them to the dependency list without raising an error. The dependency filename is taken directly from the #include directive without prepending any path. -MG also suppresses preprocessed output, as a missing header file renders this useless.

This feature is used in automatic updating of makefiles.

-MM

Like -M but do not mention header files that are found in system header directories, nor header files that are included, directly or indirectly, from such a header.

This implies that the choice of angle brackets or double quotes in an #include directive does not in itself determine whether that header will appear in -MM dependency output. This is a slight change in semantics from GCC versions 3.0 and earlier.

-MMD

Like -MD except mention only user header files, not system header files.

-MP

This option instructs CPP to add a phony target for each dependency other than the main file, causing each to depend on nothing. These dummy rules work around errors make gives if you remove header files without updating the Makefile to match.

This is typical output:

 test.o: test.c test.h
 
 test.h:

-MQ target (C/C++ Only)

Same as -MT, but it quotes any characters which are special to Make. -MQ '$(objpfx)foo.o' gives

 $$(objpfx)foo.o: foo.c

The default target is automatically quoted, as if it were given with -MQ.

-MT target (C/C++ Only)

Change the target of the rule emitted by dependency generation. By default CPP takes the name of the main input file, including any path, deletes any file suffix such as .c, and appends the platform's usual object suffix. The result is the target.

An -MT option will set the target to be exactly the string you specify. If you want multiple targets, you can specify them as a single argument to -MT, or use multiple -MT options.

For example, -MT '$(objpfx)foo.o' might give

 $(objpfx)foo.o: foo.c

-nocpp (Fortran Only)

Do not run the source preprocessor (cpp) on all input source files. See -cpp, -E, and ftpp for more information on controlling preprocessing.

-no-gcc (Fortran Only)

Disables predefined preprocessor macros, e.g. __GNUC__

-P

Inhibit generation of linemarkers in the output from the preprocessor. This might be useful when running the preprocessor on something that is not C code, and will be sent to a program which might be confused by the linemarkers. Used with option -E, See option -E in Option Controlling the Kind of Output section.

-Uname

Cancel any previous definition of name, either built in or provided with a -D option.

-Wp,option,...

You can use -Wp,option to bypass the compiler driver and pass option directly through to the preprocessor. If option contains commas, it is split into multiple options at the commas. However, many options are modified, translated or interpreted by the compiler driver before being passed to the preprocessor, and -Wp forcibly bypasses this phase. The preprocessor's direct interface is undocumented and subject to change, so whenever possible you should avoid using -Wp and let the driver handle the options instead.

Next: Link Options, Previous: Preprocessor Options, Up: Invoking Path64

3.11 Passing Options to the Assembler

You can pass options to the assembler.

-fno-asm (C/C++ Only): Do not recognize asm, inline or typeof as a keyword, so that code can use these words as identifiers. You can use the keywords __asm__, __inline__ and __typeof__ instead. -ansi implies -fno-asm.
In C++, this switch only affects the typeof keyword, since asm and inline are standard keywords. You may want to use the -fno-gnu-keywords flag instead, which has the same effect. In C99 mode (-std=c99 or -std=gnu99), this switch only affects the asm and typeof keywords, since inline is a standard keyword in ISO C99.
-Wa,option,...: Pass option as an option to the assembler. If option contains commas, it is split into multiple options at the commas.

Next: Code Gen Options, Previous: Assembler Options, Up: Invoking Path64

3.12 Options Controlling the Linker and Libraries

These options come into play when the compiler links object files into an executable output file. They are meaningless if the compiler is not doing a link step.

object-file-name

A file name that does not end in a special recognized suffix is considered to name an object file or library. (Object files are distinguished from libraries by the linker according to the file contents.) If linking is done, these object files are used as input to the linker.

-ar

Instructs the compiler to create an archive file instead of a shared object or executable file. To specify an archive file name use -o filename. Before creating the archive file, template entities needed by the archived objects are instantiated. When pathCC invokes the compiler with -ar specified, it implicitly passes options -c and -r to the compiler. In addition the filename of the archive and object files being created are passed. Option -WR,option-listis used to pass required options that can be used concurrently with the -c option.

Note options specified with the -WR,option-list must include all objects that will be incorporated in the archive, otherwise prelinked internal errors will be emitted. In the following example:

 pathCC -ar -WR,-v -o liba.a file1.o file2.o file3.o

liba.a is an archive which incorporates files file1.o, file2.o, and file3.o. Object files file1.o, file2.o, and file3.o are prelinked to instantiate all required template entities. Then the ar -r -c -v liba.a file1.o file2.o file3.o command is invoked. Even if only file3.o needs to be replaced in liba.a, all three object files must be specified.

-c

-S

-E

If any of these options is used, then the linker is not run, and object file names should not be used as arguments. See Overall Options.

-ffast-stdlib

-fno-fast-stdlib

Instructs the compiler to generate code that links against special versions of some standard library routines (e.g., fast versions of the standard library routines). Specifying -fno-fast-stdlib instructs the compiler not to generate code that links against fast versions of standard library routines. Linking code with -fno-fast-stdlib that has not been compiled using this flag may emit linker errors. Note specifying -ffsat-stdlib implies -OPT:fast_stdlib=ON. The default is -ffast-stdlib.

-H

Print the name of each header file used, in addition to other normal activities. Each name is indented to show how deep in the #include stack it is. Precompiled header files are also printed, even if they are found to be invalid; an invalid precompiled header file is printed with ...x and a valid one with ...! .

-l library

Search the library named library when linking. (The second alternative with the library as a separate argument is only for POSIX compliance and is not recommended.)

It makes a difference where in the command you write this option; the linker searches and processes libraries and object files in the order they are specified. Thus, foo.o -lz bar.o searches library z after file foo.o but before bar.o. If bar.o refers to functions in z, those functions may not be loaded.

The linker searches a standard list of directories for the library, which is actually a file named liblibrary.a. The linker then uses this file as if it had been specified precisely by name.

The directories searched include several standard system directories plus any that you specify with -L.

Normally the files found this way are library files—archive files whose members are object files. The linker handles an archive file by scanning through it for members which define symbols that have so far been referenced but not defined. But if the file that is found is an ordinary object file, it is linked in the usual fashion. The only difference between using an -l option and specifying a file name is that -l surrounds library with lib and .a and searches several directories.

-nostartfiles

Do not use the standard system startup files when linking. The standard system libraries are used normally, unless -nostdlib or -nodefaultlibs is used.

-nodefaultlibs

Do not use the standard system libraries when linking. Only the libraries you specify will be passed to the linker. The standard startup files are used normally, unless -nostartfiles is used. The compiler may generate calls to memcmp, memset, memcpy and memmove. These entries are usually resolved by entries in libc. These entry points should be supplied through some other mechanism when this option is specified.

-nostdinc

Instructs the compiler to skip the standard directory (i.e. /usr/include/) when searching for #include files and files named in the INCLUDE statements.

-nostdinc++ (C++ Only)

Do not search for header files in the standard directories specific to C++, but do still search the other standard directories. (This option is used when building the C++ library.)

-nostdlib

Do not use the standard system startup files or libraries when linking. No startup files and only the libraries you specify will be passed to the linker. The compiler may generate calls to memcmp, memset, memcpy and memmove. These entries are usually resolved by entries in libc. These entry points should be supplied through some other mechanism when this option is specified.

One of the standard libraries bypassed by -nostdlib and -nodefaultlibs is libgcc.a, a library of internal subroutines that the compiler uses to overcome shortcomings of particular machines, or special needs for some languages. In most cases, you need libgcc.a even when you want to avoid other standard libraries. In other words, when you specify -nostdlib or -nodefaultlibs you should usually specify -lgcc as well. This ensures that you have no unresolved references to internal GCC library subroutines.

-objectlist filename

Instructs the compiler to open filename to retrieve the list of files to be linked.

-shared

Produce a shared object which can then be linked with other objects to form an executable. Not all systems support this option. For predictable results, you must also specify the same set of options that were used to generate code (-fpic, -fPIC, or model suboptions) when you specify this option.¹

-shared-libgcc

-static-libgcc

On systems that provide libgcc as a shared library, these options force the use of either the shared or static version respectively. If no shared version of libgcc was built when the compiler was configured, these options have no effect.

There are several situations in which an application should use the shared libgcc instead of the static version. The most common of these is when the application wishes to throw and catch exceptions across different shared libraries. In that case, each of the libraries as well as the application itself should use the shared libgcc.

Therefore, the pathCC drivers automatically add -shared-libgcc whenever you build a shared library or a main executable, because C++ programs typically use exceptions, so this is the right thing to do.

If, instead, you use the pathcc driver to create shared libraries, you may find that they will not always be linked with the shared libgcc. If the compiler finds, at its configuration time, that you have a non-GNU linker or a GNU linker that does not support option --eh-frame-hdr, it will link the shared version of libgcc into shared libraries by default. Otherwise, it will take advantage of the linker and optimize away the linking with the shared version of libgcc, linking with the static version of libgcc by default. This allows exceptions to propagate through such shared libraries, without incurring relocation costs at library load time.

However, if a library or main executable is supposed to throw or catch exceptions, you must link it using the pathCCdriver or using the option -shared-libgcc, such that it is linked with the shared libgcc.

-static

--static

On systems that support dynamic linking, this prevents linking with the shared libraries. On other systems, this option has no effect. --static is equivalent to -static, except --static does not incite the compiler to emit warnings regarding possible confusion with -static-data.

-static-data (Fortran Only)

Instructs the compiler to statically allocate all local variables which are initially set to zero and will exist for the life of the program. Global data is allocated as part of the compiled object file. The total size of any object file is limited to 2 GB. The total size of a program loaded using multiple object files are allowed to exceed the 2 GB limit. Multiple common blocks each within the 2 GB size limit can be declared.

The -static-data cannot be specified when compiling an external routine that is called by a program which contains parallel loops targeting a multiprocessor system. Static and multiprocessor compiled object files can be mixed in the same executable, but a static routine cannot be called from within a parallel region.

Note option -static-data is useful when porting programs from legacy systems in which all variables are allocated as static.

-stdinc

Instructs the compiler to use a predifined include search path list.

-symbolic

Bind references to global symbols when building a shared object. Warn about any unresolved references (unless overridden by the link editor option -Xlinker -z -Xlinker defs). Only a few systems support this option.

-Xlinker option

Pass option as an option to the linker. You can use this to supply system-specific linker options which the compiler does not know how to recognize.

If you want to pass an option that takes an argument, you must use -Xlinker twice, once for the option and once for the argument. For example, to pass -assert definitions, you must write -Xlinker -assert -Xlinker definitions. It does not work to write -Xlinker "-assert definitions", because this passes the entire string as a single argument, which is not what the linker expects.

-Wl,option,...

Pass option as an option to the linker. If option contains commas, it is split into multiple options at the commas.

Next: Target Options, Previous: Link Options, Up: Invoking Path64

3.13 Options for Code Generation Conventions

These machine-independent options control the interface conventions used in code generation.

-CG:question=answer

This group of code generation option controls the optimizations and transformations of the instruction level code generator.

-CG:cflow=ON|OFF

-CG:cflow=OFF disables control flow optimization in the code generation. The default is -CG:cflow=ON.

-CG:cmp_peep=ON|OFF

Instructs the compiler to perform aggressive load execution peeps on compare operations. The default is CG:cmp_peep=OFF.

-CG:compute_to=on|off

Instructs the compiler to allow local code motion to take advantage of pipeline optimizations. For example: specify in conjunction with option -march=barcelona, i.e.when targeting versions of the Quad-Core AMD® Opteron^T^M and greater. The defaullt is CG:compute_to=OFF

-CG:cse_regs=N

When performing common subexpression elimination, instructs the compiler code generator that there are N extra integer registers available (i.e. in excess of the number provided by the CPU). N can be positive, negative, or zero. The default is positive infinity. See -CG:sse_cse_regs=N.

-CG:gcm=ON|OFF

-CG:gcm=OFF instructs the compiler to disable the instruction level global code motion optimization phase. The default is -CG:gcm=ON.

-CG:inflate_reg_request=N

Instructs the the local register allocator to increase its register request by N percent for innermost loops. The default is -CG:inflate_reg_request=0.

-CG:load_exe=N

The parameter N must be a no-negative integer which specifies the threshold for considering a memory load operation into the operand of an arithmetic instruction. If N=0 this subsumption optimization is not performed (or turned off). If the number of times the result of the memory load is used exceeds the value of N then the subsumption optimization is not performed. For example, if n=1 this subsumption is performed only when the result of the memory load has only one use. The default value of N varies with target processor and source language.

-CG:local_sched_alg=0|1|2

This option selects the basic block instruction scheduling algorithm.

To perform backward scheduling (i.e. where instructions are scheduled from the bottom to the top of the basic block) select 0.
To perform forward scheduling select 1.
To schedule the instruction twice (i.e. once in the forward direction and once in the backward direction) and take the optimal of the two schedules.

The default value for this option is determined by the x86 Path64 compiler during compilation.

-CG:locs_best=ON|OFF

When enabled the local instruction scheduler is run several times using different heuristics. The optimal schedule generated is selected. Note this option supersedes options which control local instruction scheduling, e.g. -CG:local_sched_alg and -CG:locs_shallow_depth. The default is -CG:locs_best=OFF.

-CG:locs_reduce_prefetch=ON|OFF

Setting to ON instructs the compiler to delete prefetch instructions that cannot be scheduled into unused processor cycles. Note this occurs only for backward instruction scheduling. The default is -CG:locs_reduce_prefetch=OFF.

-CG:locs_shallow_depth=ON|OFF

ON instructs the compiler to give priority to instructions that have shallow depths in the dependence graph when performing local instruction scheduling to reduce register usage. The default is -CG:locs_shallow_depth=OFF.

-CG:movnti=N

When writing memory blocks of size larger than N KB ordinary stores will be transformed to non-temporal stores. The default is N=1000.

-CG:p2align=ON|OFF

When ON instructs the compiler to align loop heads to 64-byte boundaries. The default is -CG:p2align=OFF.

-CG:p2align_freq=N

Values for N specify the execution frequency threshold. The compiler will perform branch target alignments when the execution frequency is equal to or greater than the specified threshold, N. Note this option is only valid when using feedback-direct compilation. The default is N=1000.

-CG:post_local_sched=ON|OFF

When ON, enables the loacal scheduler phase after register allocation. The default is -CG:post_local_sched=ON.

-CG:pre_local_sched=ON|OFF

When ON, enables the local scheduler phase before register allocation. The default is -CG:pre_local_sched=ON.

-CG:prefer_legacy_regs=ON|OFF

When enabled the compiler register allocator is instructed to use the first 8 integer and SSE registers when possible. Starting with the last assigned register and work upward in most recently assigned fashion where available. Note instructions which use these registers have smaller instruction sizes. For example, the lower 8 registers on x86-64 do not use the rex byte. The default is -CG:prefer_legacy_regs=OFF.

-CG:prefetch=ON|OFF

When -CG:prefetch=ON prefetch instructions are generated in the code generator. Note both -CG:prefetch=OFF and -LNO:prefetch=0 disable the generation of prefetch instructions. Only -LNO:prefetch=0 affects loop-nesting optimizations that rely on prefetch. The default is -CG:prefetch=OFF.

-CG:ptr_load_use=N

The code generator increases the latency between an instruction that loads a pointer and an instruction that uses the pointer by N cycles. Ordinarily, it is advantageous to load pointers as fast as possible so the dependent memory instructions can begin execution. However, the additional latency will force the instruction scheduler to schedule the load pointer earlier. Note the load pointer instructions include load-execute instructions which compute pointer results. The default is -CG:ptr_load_use=4.

-CG:push_pop_int_saved_regs=ON|OFF

When ON, the compiler generates push and pop instructions to save integer callee-saved registers at function prologues and epilogues. The push and pop instructions replace mov instructions to and from memory locations based off the stack pointer. The default is -CG:push_pop_int_saved_regs=OFF. When the specified target is the Quad-Core AMD Opteron^T^M processor the default is -CG:push_pop_int_saved_regs=ON.

-CG:sse_cse_regs=N

When performing common subexpression elimination, instructs the compiler code generator that there are N extra SSE registers available (i.e. in excess of the number provided by the CPU). N can be positive, negative, or zero. The default is positive infinity. See -CG:cse_regs=N.

-CG:unroll_fb_req=ON|OFF

The compiler is instructed to override cold code motion to keep the code generator from adding control flow in unrolled loops. The default is -CG:unroll_fb_req=OFF.

-CG:use_prefetchnta=ON|OFF

When enabled prefetching is performed on non-temporal data at all levels of the cache hierarchy. Note for data streaming situations when the data will not need to be reused soon. The default is -CG:use_prefetchnta=OFF.

-CG:use_test=ON|OFF

When enabled the code generator is forced to use TEST instruction instead of the CMP instruction. The default is -CG:use_test=OFF.

-GRA:question=answer

Global register allocation (GRA) is the process of multiplexing a large number of target program variables onto a small number of CPU registers. The code generator implements global register allocation when certain optimization levels are specified.

-GRA:home=ON|OFF: Instructs the compiler to perform a rematerialization optimization for non-local user variables in the register allocator. The default is -GRA:home=ON.
-GRA:optimize_boundary=ON|OFF: Instructs the compiler to permit the register allocator to assign the same register to different variables in the same basic-block. The default is -GRA:optimize_boundary=OFF.
-GRA:prioritize_by_density=ON|OFF: Instructs the compiler's GPA to prioritize register assignments to variables based on the variable's reference density and not on reference count. The default is -GRA:prioritize_by_density=OFF.
-GRA:unspill=ON|OFF: The compiler is instructed to mitigate existing and suboptimal boundry conditions between global register allocation and local register allocation by unspilling register candidates which were really available at those boundary conditions. The default is -GRA:unspill=OFF.

Next: Diagnostic Options, Previous: Code Gen Options, Up: Invoking Path64

3.14 Specifying Target Environment and Machine

x86 Path64 provides options that will switch to another cross-compiler or target environment. The target environment is the system upon which the executable code will be run.

-TENV:question=answer

These options control the target environment assumed and/or produced by the compiler.

-TENV:frame_pointer=ON|OFF

Setting this option to ON tells the compiler to use the frame pointer register to address local variables in the function stack frame. Generally, if the compiler determines that the stack pointer is fixed it will use the stack pointer to address local variables throughout the function invocation in place of the frame pointer. This frees up the frame pointer for other purposes.
The default is ON for C/C++ and OFF for Fortran. This flag defaults to ON for C/C++ because the exception handling mechanism relies on the frame pointer register being used to address local variables. This flag can be turned OFF for C/C++ programs that do not generate exceptions.

-TENV:simd_dmask=ON|OFF

When set to OFF the SIMD floating-point denormalized-operation exception is unmasks. The default is ON

-TENV:simd_imask=ON|OFF

When set to OFF the SIMD floating-point invalid-operation exception is unmasks. The default is ON

-TENV:simd_omask=ON|OFF

When set to OFF the SIMD floating-point overflow exception is unmasks. The default is ON

-TENV:simd_pmask=ON|OFF

When set to OFF the SIMD floating-point precision exception is unmasks. The default is ON

-TENV:simd_umask=ON|OFF

When set to OFF the SIMD floating-point underflow exception is unmasks. The default is ON

-TENV:simd_zmask=ON|OFF

When set to OFF the SIMD floating-point zero-divide exception is unmasks. The default is ON

-TENV:X=0,1,2,3,4

Use this option to specify the level of enabled exceptions which will be granted for purposes of performing speculative code motion. The default level of enablement is 1 for all optimization levels. Instructions will not be speculated or moved above a branch by the optimizer unless all exceptions generated by the move are disabled.

0: Speculative code motion may not be performed.
1: Safe speculative code motion may be performed. IEEE-754 underflow exceptions must be disabled.
2: Disables all IEEE-754 exceptions except divide-by-zero
3: Disables all IEEE-754 exceptions including divide-by-zero.
4: Memory exceptions are disabled.

Up: Target Options

3.14.1 Hardware Models and Configurations

Earlier we discussed the option -TENV: which chooses among different environments for completely different target machines.

In addition, each of these target machine types can have its own special options, starting with -m, to choose among various hardware models or configurations—for example, 80386 vs AMD Opteron, floating coprocessor or none. A single installed version of the compiler can compile for any model or configuration, according to the options specified.

Some configurations of the compiler also support additional special options, usually for compatibility with other compilers on the same platform.

These -m options are defined for the i386 and x86-64 family of computers in 32-bit and 64-bit environments:

-march=cpu-type

-mtune=cpu-type

-mcpu=cpu-type

Generate instructions for the machine type cpu-type. The choices for cpu-type are the same as for -march, -mtune, and -mcpu. Moreover, specifying -march=cpu-type implies -mtune=cpu-type.

Tune to cpu-type everything applicable about the generated code, except for the ABI and the set of available instructions. The choices for cpu-type are:

anyx86: Produce code optimized for the most common x86-32/x86-64 processors. If you know the CPU on which your code will run, then you should use the corresponding -march option instead of -march=anyx86. But, if you do not know exactly what CPU users of your application will have, then you should use this option.
As new processors are deployed in the marketplace, the behavior of this option will change. Therefore, if you upgrade to a newer version of x86 Path64, the code generated option will change to reflect the processors that were most common when that version of Path64 was released.
auto: This selects the CPU to tune for at compilation time by determining the processor type of the compiling machine. Using -march=auto will produce code optimized for the local machine under the constraints of the selected instruction set. Using -march=auto will enable all instruction subsets supported by the local machine (hence the result might not run on different machines).
athlon: The original AMD Athlon^T^M Processor.
athlon64: The AMD Athlon^T^M 64 is the K8 core based CPUs, and eighth-generation processor featuring x86-64 technology.
athlon64fx: The AMD Athlon^T^M 64 FX is the K8 core based CPUs with dual cores.
barcelona: The third-generation AMD Opteron^T^M Processor. The Quad-Core AMD Opteron^T^M K10H core based CPUs with x86-64 instruction set support.
core: The Intel Core 2 processor with Intel64 support.
em64t: Intel x86-64 instruction set support.
opteron: The second-generation AMD Opteron^T^M with x86-64 instruction set support.
pentium4: Intel Pentium 4 CPU with MMX, SSE and SSE2 instruction set support.
wolfdale: Intel's dual-core Core 2 Duo processors.
xeon: Intel's Xeon based CPU's with x86-64 instruction set support.

While picking a specific cpu-type will schedule things appropriately for that particular chip, the compiler will not generate any code that does not run on the i386 without the -march=cpu-type option being used.

-msse

-mno-sse

-msse2

-mno-sse2

-msse3

-mno-sse3

-msse4a

-mno-msse4a

-m3dnow

-mno-3dnow

These switches enable or disable the use of instructions in the MMX, SSE, SSE2, SSE3, SSE4a or 3DNow! extended instruction sets. These extensions are also available as built-in functions.

These options will enable the compiler to use these extended instructions in generated code.

-msse
-mno-msse: Enables/disables the use of SSE2 and SSE3 instructions. Note disabling SSE2 instructions when specifying -m64 will emit a warning message.
-msse2
-mno-msse2: Enables/disables the use of SSE2 instructions. Note disabling SSE2 instructions when specifying -m64 will emit a warning message. Specifying either -m64 or -m32 enables this option.
-msse
-mno-msse3: Enables/disables the use of SSE3 instructions. Specifying options -march=barcelona, -march=em64t, or -march=core enables this option. The default is -mno-msse3.
-msse4a
-mno-msse4a: Enables/disables the use of SSE4a instructions. Specifying options -march=barcelona enables this option. The default is -mno-msse4a.
-m3dnow
-mno-m3dnow: Enables/disables the use of 3DNow! instructions. The default is -mno-m3dnow.

Note applications which perform runtime CPU detection must compile separate files for each supported architecture, using the appropriate flags. In particular, the file containing the CPU detection code should be compiled without these options.

-m32

-m64

Generate code for a 32-bit or 64-bit environment. The 32-bit environment sets int, long and pointer to 32 bits and generates code that runs on any i386 system. The compiler generates x86 or IA32 32-bit ABI. The 64-bit environment sets int to 32 bits and long and pointer to 64 bits and generates code for AMD's x86-64 architecture. The compiler generates AMD64, INTEL64, x86-64 64-bit ABI. The default on a 32-bit host is 32-bit ABI. The default on a 64-bit host is 64-bit ABI if the target platform specified is 64-bit, otherwise the default is 32-bit.

-mcmodel=small|medium

Generate code for the small or medium memory models. The compiler generates these models:

Specifying small implies the program and its symbols must be linked in the lower 2 GB of the address space. Pointers are 64 bits. Programs can be statically or dynamically linked. This is the default memory model.
Specifying medium implies the program is linked in the lower 2 GB of the address space but symbols can be located anywhere in the address space. Programs can be statically or dynamically linked, but building of shared libraries are not supported with the medium model.

Note most programs will execute using 32-bit code and data pointers defined by the small memory model. If a program requires 64-bit data pointers then medium must be selected. Currently the compiler does not support the large memory model.

Next: Debugging Options, Previous: Target Options, Up: Invoking Path64

3.15 Options to Control Diagnostic

Traditionally, diagnostic messages have been formatted irrespective of the output device's aspect (e.g. its width, ...). The options described below can be used to control the diagnostic messages formatting algorithm, e.g. how many characters per line, how often source location information should be reported, etc. Right now, only the C++ front end can honor these options. However it is expected, in the near future, that the remaining front ends would be able to digest them correctly.

-C (Fortran only)

Performs run-time array subscript range checking. A subscript range violation will trigger a fatal run-time error. Note if the environment variable F90_BOUNDS_CHECK_ABORT is set to YES the program aborts.

-clist (C Only)

-CLIST:=answer (C Only)

-CLIST:question=answer (C Only)

This option group is a C language diagnostic tool. Option group CLIST: instructs the compiler to emit internal program representation back into C code, after IPA inlining and loopâ€“nest transformations. The generated C code may not always be compatible and is written to two files, a header file containing fileâ€“scope declarations, and a file containing function definitions.

Option -clist is equivalent to -CLIST:=ON. Specifing any variation of option -CLIST:question=answer implies -clist, (i.e. with the exception of â€“CLIST:=OFF). The individual controls in this group are as follows:

-clist: Equivalent to enabling -CLIST:, i.e. -CLIST:=ON.
-CLIST:=ON|OFF: Option -CLIST:=ON instructs the compiler to emit internal program representation back into the C code. This option is implied if any of the -CLIST:=question=answer options are specified. -CLIST:=ON is equivalent to -clist.
-CLIST:dotc_file=filename: Instructs the compiler to write the program units to the specified source file filename. The default suffix for filename is .w2c.c.
-CLIST:doth_file=filename: Instructs the compiler to write the file-scope declarations to the specified file filename. The default suffix for filename is .w2c.h.
-CLIST:emit_pfetch=ON|OFF: Instructs the compiler to insert comments includes prefetch information in the transformed source file. The default is -CLIST:emit_pfetch=OFF.
-CLIST:linelength=N: Instructs the compiler to set the maximum line length to N characters. The default is a unlimited number of characters-per-line.
-CLIST:show=ON|OFF: Instructs the compiler to print the input and output file names to stderr. The default is -CLIST:show=ON.

-ffortran-bounds-check (Fortran Only)

Checks bounds. -ffortran-bounds-check is equivalent to option -C.

-flist (Fortran Only)

-FLIST:=answer (Fortran Only)

-FLIST:question=answer (Fortran Only)

This option group is a Fortran language diagnostic tool. Option group FLIST: instructs the compiler to emit internal program representation back into the Fortran code, after IPA inlining and loopâ€“nest transformations. The generated Fortran code may not always be compatible and compile successfully.

Option -flist is equivalent to -FLIST:=ON. Specifing any variation of option -FLIST:question=answer implies -flist, (i.e. with the exception of â€“FLIST:=OFF). The individual controls in this group are as follows:

-flist

Equivalent to enabling -FLIST:, i.e. -FLIST:=ON.

-FLIST:=ON|OFF

Option -FLIST:=ON instructs the compiler to emit internal program representation back into the Fortran code. This option is implied if any of the -FLIST:=question=answer options are specified. -FLIST:=ON is equivalent to -flist.

-FLIST:ansi_format=ON|OFF

Instructs the compiler to set ANSI format. When set to ON, the compiler is instructed to use a space instead of a tab for indentations and to write a maximum of 72 characters-per-line. The default is -FLIST:ansi_format=OFF.

-FLIST:emit_pfetch=ON|OFF

Instructs the compiler to write prefetch information as comments in the transformed source file. The compiler will write PREFETCH in the listing to identify the reference being prefetched and will include:

the variable reference with an offset in bytes
an indication of read/write
a stride for each dimension
a number in the range for 1 to 3 (with 1 being the lowest) which reflects the confidence in the prefetch analysis

The written comments appear after a read/write to a variable and note the identifier of the prefetch-spec for each level of the cache. The default is -FLIST:emit_pfetch=OFF.

-FLIST:ftn_file=filename

Instructs the compiler to write the program to the file, filename. The default suffix for filename is .w2f.f.

-FLIST:linelength=N

Instructs the compiler to set the maximum line length to N characters. The default is -FLIST:linelength=72.

-FLIST:show=ON|OFF

Instructs the compiler to print the input and output file names to stderr. The default is ON.

-fpermissive

-fno-permissive

Option -fpermissive will downgrade some diagnostics about nonconformant code from errors to warnings. Thus, using -fpermissive will allow some nonconforming code to compile. -fno-permissive maintains diagnostics about nonconformant code as errors.

Using the -fpermissive flag will also let the compiler accept the code, by marking all function calls for which no declaration is visible at the time of definition of the template for later lookup at instantiation time, as if it were a dependent call. We do not recommend using â€˜-fpermissiveâ€™ to work around invalid code, and it will also only catch cases where functions in base classes are called, not where variables in base classes are used.

-fullwarn

Instructs the compiler to generate comment level diagnostics. It may be beneficial to specify this option during program development. The default is to disable this diagnostic messaging.

-pedantic-errors (C Only)

Issue all the errors demanded by strict ISO C and ISO C++; reject all programs that use forbidden extensions, and some other programs that do not follow ISO C and ISO C++. For ISO C, follows the version of the ISO C standard specified by any -std option used.

Valid ISO C and ISO C++ programs should compile properly with or without this option (though a rare few will require -ansi or a -std option specifying the required version of ISO C). However, without this option, certain GNU extensions and traditional C and C++ features are supported as well. With this option, they are rejected.

-pedantic-errors does not cause error messages for use of the alternate keywords whose names begin and end with __. Pedantic errors are also disabled in the expression that follows __extension__. However, only system header files should use these escape routes; application programs should avoid them.

Some users try to use -pedantic-errors to check programs for strict ISO C conformance. They soon find that it does not do quite what they want: it finds some non-ISO practices, but not all—only those for which ISO C requires a diagnostic, and some others for which diagnostics have been added.

Where the standard specified with -std represents a GNU extended dialect of C, such as gnu89 or gnu99, there is a corresponding base standard, the version of ISO C on which the GNU extended dialect is based. Errors from -pedantic-errors are given where they are required by the base standard.

-subverbose

This option is not supported by the compiler and is ignored if specified.

-trapuv

Instructs the compiler to initialize variables to the value NaN, forcing a program crash if it uses uninitialized variables (i.e. traps uninitialized variables). Note -trapuv affects local scalar and array variables plus memory returns by alloca(). It does not influence the behavior of globals, malloc()ed memory or Fortran common variables.

-zerouv

Instructs the compiler to initialize variables to zero. Note -zerouv affects local scalar and array variables plus memory returns by alloca(). It does not influence the behavior of globals, malloc()ed memory or Fortran common variables.

Next: Warning Options, Previous: Diagnostic Options, Up: Invoking Path64

3.16 Options for Debugging Your Program

x86 Path64 has various special options that are used for evaluating and debugging your program:

-dletters

This option specifies debugging dumps, into a file named dumpname, during compilation at phases specified by letters. This is used for debugging the RTL-based passes of the compiler. dumpname is generated from the name of the output file, if explicity specified and it is not an executable, otherwise it is the basename of the source file.

-dD: Generate a list of all non-predifined macro directives, at the end of preprocessing, in addition to normal output.
-dI: Output #include directives in addition to preprocessor results.
-dM: Generate a list of directives for all macros.
-dN: Generate a list of all macro names defined.

-fprofile-arcs

Add code so that program flow arcs are instrumented. During execution the program records how many times each branch and call is executed and how many times it is taken or returns. When the compiled program exits it saves this data to a file called auxname.gcda for each source file. The data may be used for profile-directed optimizations (-fbranch-probabilities), or for test coverage analysis (-ftest-coverage). Each object file's auxname is generated from the name of the output file, if explicitly specified and it is not the final executable, otherwise it is the basename of the source file. In both cases any suffix is removed (e.g., foo.gcda for input file foo.c, or dir/foo.gcda for output file specified as -o dir/foo.o).

-frandom-seed=string (C/C++ Only)

This option provides a seed that the compiler uses when it would otherwise use random numbers. It is used to generate certain symbol names that have to be different in every compiled file. It is also used to place unique stamps in coverage data files and the object files that produce them. You can use the -frandom-seed option to produce reproducibly identical object files.

The string can be any character string and should be different for every file you compile.

-ftest-coverage

Produce a notes file that the gcov code-coverage utility can use to show program coverage. Each source file's note file is called auxname.gcno. Refer to the -fprofile-arcs option above for a description of auxname and instructions on how to generate test coverage data. Coverage data will match the source files more closely, if you do not optimize.

-g

-glevel

Produce debugging information in the operating system's native format, DWARF 2, and also use level to specify how much information. The default level is 0. Option -g without a specific level is equivalent to debug option level -g2.

Path64 allows you to use -g with -O. The shortcuts taken by optimized code may occasionally produce surprising results: some variables you declared may not exist at all; flow of control may briefly move to where you did not expect it; some statements may not be executed because they compute constant results or their values were already at hand; some statements may execute in different places because they were moved out of loops.

-g0: Level 0 generates no debug information for symbolic debugging.
-g1: Level 1 produces minimal information, i.e. enough for making backtraces in parts of the program that you don't plan to debug. This includes descriptions of functions and external variables, but no information about local variables and no line numbers. Cuts back on the overhead of full debug information. At this level --export-dynamic is passed to the linker.
-g2: Level 2 produces information for symbolic debugging. If no optimization options levels are selected, the optimization option level -O0 is invoked to maintain the accuracy of the debugging information. Note the accuracy of the debugging information cannot be guaranteed if optimization option levels -O1, -O2, or -O3 are invoked. IPA is disabled, if option -ipa is specified in conjunction with option -g2.
-g3: Level 3 includes extra information, such as all the macro definitions present in the program. Some debuggers support macro expansion when you use -g3.
-gdwarf-2: Produces debugging information in DWARF version 2 format.
-gdwarf-20: Produces DWARF 2 debugging information at debug level 0.
-gdwarf-21: Produces DWARF 2 debugging information at debug level 1.
-gdwarf-22: Produces DWARF 2 debugging information at debug level 2.
-gdwarf-23: Produces DWARF 2 debugging information at debug level 3.

-p

-pg

Generate extra code to write profile information suitable for the analysis program prof. You must use this option when compiling the source files you want data about, and you must also use it when linking. The -p option enables application level profiling, see option -profile to enable library level profiling.

-profile

Generate extra code to write profile information suitable for the analysis program gprof. You must use this option when compiling the source files you want data about, and you must also use it when linking. The -profile option enables application level and library level profiling.

Next: Environment Variables, Previous: Debugging Options, Up: Invoking Path64

3.17 Options to Request or Suppress Warnings

Warnings are diagnostic messages that report constructions which are not inherently erroneous but which are risky or suggest there may have been an error.

You can request many specific warnings with options beginning -W, for example -Wimplicit to request warnings on implicit declarations. Some of these specific warning options also has a negative form beginning -Wno- to turn off warnings; for example, -Wno-implicit.

Most of these options have both positive and negative forms; the negative form of -Wfoo would be -Wno-foo. This manual typically defines only one of these two forms, whichever one is not the default.

Next: C Warning, Up: Warning Options

3.17.1 Options that Control Language Independent Warnings

The following options control the amount and kinds of warnings produced by the x86 Path64 compiler for the C/C++ and Fortran Dialects; for further, language-specific options also refer to C Dialect Options and Fortran Dialect Options.

-w

Inhibit all warning messages.

-Wall

Turns on all optional warnings which are desirable for normal code. Enables all the warnings about constructions that some users consider questionable, and that are easy to avoid (or modify to prevent the warning), even in conjunction with macros.

-Wbad-function-cast

Warn whenever a function call is cast to a non-matching type. For example, warn if int malloc() is cast to anything *.

-Wdeprecated

-Wno-deprecated

Do not warn about usage of deprecated features.

-Wdisabled-optimization

-Wno-disabled-optimization

Warn if a requested optimization pass is disabled. This warning does not generally indicate that there is anything wrong with your code; it merely indicates that the compiler's optimizers were unable to handle the code effectively. Often, the problem is that your code is too big or too complex; GCC will refuse to optimize programs when the optimization itself is likely to take inordinate amounts of time.

-Wdiv-by-zero

-Wno-div-by-zero

Do not warn about compile-time integer division by zero. Floating point division by zero is not warned about, as it can be a legitimate way of obtaining infinities and NaNs.

-Wendif-labels

-Wno-endif-labels

Do not warn whenever an #else or an #endif are followed by text.

-Werror

-Wno-error

Make all warnings into errors.

Make the specified warning into an error. The specifier for a warning is appended, for example -Werror=switch turns the warnings controlled by -Wswitch into errors. This switch takes a negative form, to be used to negate -Werror for specific warnings, for example -Wno-error=switch makes -Wswitch warnings not be errors, even when -Werror is in effect. You can use the -fdiagnostics-show-option option to have each controllable warning amended with the option which controls it, to determine what to use with this option.

Note that specifying -Werror=foo automatically implies -Wfoo. However, -Wno-error=foo does not imply anything.

-Wfloat-equal

-Wno-float-equal

Warn if floating point values are used in equality comparisons.

-Wimport

-Wno-import

Inhibit warning messages about the use of the #import directive.

-Wlarger-than-len

-Wno-larger-than-len

Warn whenever an object of larger than len bytes is defined.

-Wno-deprecated-declarations

Do not warn about uses of functions , variables , and types marked as deprecated by using the deprecated attribute.

-woff

Turn off all named warnings

-woffall

Turn off all warnings

-woffoptions

Turn off all warnings regarding command-line options

-woffnum

Instructs the compiler to suppress the specified warning.

For example:

 pathcc -woff2056 -o foo foo.c

Instructs the compiler to suppress warning message number 2056.

 pathcc -woff2056-2300 -o foo foo.c

Instructs the compiler to suppress warning message numbers 2056 thru 2300.

 pathcc -woff2056-2300,2420-2500 -o foo foo.c

Instructs the compiler to suppress warning message number 2056 thru 2300 and 2420 thru 2500.

-Wundef

-Wno-undef

Warn if an undefined identifier is evaluated in an #if directive.

-Wuninitialized

-Wno-uninitialized

Warn if an automatic variable is used without first being initialized or if a variable may be clobbered by a setjmp call.

These warnings are possible only in optimizing compilation, because they require data flow information that is computed only when optimizing. If you do not specify -O, you will not get these warnings. Instead, the compiler will issue a warning about -Wuninitialized requiring -O.

If you want to warn about code which uses the uninitialized value of the variable in its own initializer, use the -Winit-self option.

These warnings occur for individual uninitialized or clobbered elements of structure, union or array variables as well as for variables which are uninitialized or clobbered as a whole. They do not occur for variables or elements declared volatile. Because these warnings depend on optimization, the exact variables or elements for which there are warnings will depend on the precise optimization options.

Note that there may be no warning about a variable that is used only to compute a value that itself is never used, because such computations may be deleted by data flow analysis before the warnings are printed.

These warnings are made optional because the compiler is not smart enough to see all the reasons why the code might be correct despite appearing to have an error. Here is one example of how this can happen:

 {
 int x;
 switch (y)
 {
 case 1: x = 1;
 break;
 case 2: x = 4;
 break;
 case 3: x = 5;
 }
 foo (x);
 }

If the value of y is always 1, 2 or 3, then x is always initialized, but the compiler doesn't know this. Here is another common case:

 {
 int save_y;
 if (change_y) save_y = y, y = new_y;
 ...
 if (change_y) y = save_y;
 }

This has no bug because save_y is used only if it is set.

This option also warns when a non-volatile automatic variable might be changed by a call to longjmp. These warnings as well are possible only in optimizing compilation.

The compiler sees only the calls to setjmp. It cannot know where longjmp will be called; in fact, a signal handler could call it at any point in the code. As a result, you may get a warning even when there is in fact no problem because longjmp cannot in fact be called at the place which would cause a problem.

Some spurious warnings can be avoided if you declare all the functions you use that never return as noreturn. This warning is enabled by -Wall.

-Wunknown-pragmas

-Wno-unknown-pragmas

Warn when a #pragma directive is encountered which is not understood by the compiler. If this command line option is used, warnings will even be issued for unknown pragmas in system header files. This is not the case if the warnings were only enabled by the -Wall command line option.

-Wunreachable-code

-Wno-unreachable-code

Warn if the compiler detects that code will never be executed.

This option is intended to warn when the compiler detects that at least a whole line of source code will never be executed, because some condition is never satisfied or because it is after a procedure that never returns.

It is possible for this option to produce a warning even though there are circumstances under which part of the affected line can be executed, so care should be taken when removing apparently-unreachable code.

For instance, when a function is inlined, a warning may mean that the line is unreachable in only one inlined copy of the function.

This option is not made part of -Wall because in a debugging version of a program there is often substantial code which checks correct functioning of the program and is, hopefully, unreachable because the program does work. Another common use of unreachable code is to provide behavior which is selectable at compile-time.

-Wunused

-Wno-unused

Warns whenever a variable is unused. Note in order to get a warning about an unused function parameter, you must specify -Wunused-parameter.

-Wunused-function

-Wno-unused-function

Warn whenever a static function is declared but not defined or a non-inline static function is unused. This warning is enabled by -Wall.

-Wunused-label

-Wno-unused-label

Warn whenever a label is declared but not used. This warning is enabled by -Wall.

-Wunused-parameter

-Wno-unused-parameter

Warn whenever a function parameter is unused aside from its declaration.

-Wunused-value

-Wno-unused-value

Warn whenever a statement computes a result that is explicitly not used. This warning is enabled by -Wall.

-Wunused-variable

-Wno-unused-variable

Warn whenever a local variable or non-constant static variable is unused aside from its declaration. This warning is enabled by -Wall.

-Wwrite-strings

-Wno-write-strings

When compiling C, give string constants the type

const
char[

length] so that copying the address of one into a non-const char * pointer will get a warning; when compiling C++, warn about the deprecated conversion from string literals to char *. This warning, by default, is enabled for C++ programs. These warnings will help you find at compile time code that can try to write into a string constant, but only if you have been very careful about using const in declarations and prototypes. Otherwise, it will just be a nuisance; this is why we did not make -Wall request these warnings.

Previous: Language Indep, Up: Warning Options

3.17.2 Options that Control C/C++ Warnings

The following options control the amount and kinds of warnings produced by the compiler for the C/C++ dialect only; for further, language-specific options also refer to C Dialect Options.

-Waggregate-return

Warn if any functions that return structures or unions are defined or called. (In C/C++ language where you can return an array, this also elicits a warning.)

-Wcast-align

-Wno-cast-align

Warn whenever a pointer is cast such that the required alignment of the target is increased. For example, warn if a char * is cast to an int * on machines where integers can only be accessed at two- or four-byte boundaries.

-Wchar-subscripts

-Wno-char-subscripts

Warn if an array subscript has type char. This is a common cause of error, as programmers often forget that this type is signed on some machines. This warning is enabled by -Wall.

-Wcomment

-Wno-comment

Warn whenever a comment-start sequence /* appears in a /* comment, or whenever a Backslash-Newline appears in a // comment. This warning is enabled by -Wall.

-Wconversion

-Wno-conversion

Warn if a prototype causes a type conversion that is different from what would happen to the same argument in the absence of a prototype. This includes conversions of fixed point to floating and vice versa, and conversions changing the width or signedness of a fixed point argument except when the same as the default promotion.

Also, warn if a negative integer constant expression is implicitly converted to an unsigned type. For example, warn about the assignment x = -1 if x is unsigned. But do not warn about explicit casts like (unsigned) -1.

-Wdeclaration-after-statement

Warn when a declaration is found after a statement in a block. This construct, known from C++, was introduced with ISO C99 and is by default allowed in Path64. It is not supported by ISO C90.

-Wformat

-Wno-format

Check calls to printf and scanf, etc., to make sure that the arguments supplied have types appropriate to the format string specified, and that the conversions specified in the format string make sense. This includes standard functions, and others specified by format attributes , in the printf, scanf, strftime and strfmon (an X/Open extension, not in the C standard) families (or other target-specific families). Which functions are checked without format attributes having been specified depends on the standard version selected, and such checks of functions without the attribute specified are disabled by -ffreestanding or -fno-builtin.

The formats are checked against the format features supported by GNU libc version 2.2. These include all ISO C90 and C99 features, as well as features from the Single Unix Specification and some BSD and GNU extensions. Other library implementations may not support all these features; The compiler does not support warning about features that go beyond a particular library's limitations. However, if -pedantic is used with -Wformat, warnings will be given about format features not in the selected standard version (but not for strfmon formats, since those are not in any version of the C standard). See Options Controlling C Dialect.

Since -Wformat also checks for null format arguments for several functions, -Wformat also implies -Wnonnull.

-Wformat is included in -Wall. For more control over some aspects of format checking, the options -Wformat-y2k, -Wno-format-extra-args, -Wno-format-zero-length, -Wformat-nonliteral, -Wformat-security, and -Wformat=2 are available, but are not included in -Wall.

-Wformat-nonliteral

-Wno-format-nonliteral

If -Wformat is specified, also warn if the format string is not a string literal and so cannot be checked, unless the format function takes its format arguments as a va_list.

-Wformat-security

-Wno-format-security

If -Wformat is specified, also warn about uses of format functions that represent possible security problems. At present, this warns about calls to printf and scanf functions where the format string is not a string literal and there are no format arguments, as in printf (foo);. This may be a security hole if the format string came from untrusted input and contains %n. (This is currently a subset of what -Wformat-nonliteral warns about, but in future warnings may be added to -Wformat-security that are not included in -Wformat-nonliteral.)

-wid-clash

-wno-id-clash

Warns if two identifiers have the exact same first num characters.

-Wimplicit

-Wno-implicit

Same as -Wimplicit-int and -Wimplicit-function-declaration. This warning is enabled by -Wall.

-Wimplicit-function-declaration

-Wno-implicit-function-declaration

Give a warning (or error) whenever a function is used before being declared. The form -Wno-error-implicit-function-declaration is not supported. This warning is enabled by -Wall (as a warning, not an error).

-Wimplicit-int

-Wno-implicit-int

Warn when a declaration does not specify a type. This warning is enabled by -Wall.

-Winline

-Wno-inline

Warn if a function can not be inlined and it was declared as inline. Even with this option, the compiler will not warn about failures to inline functions declared in system headers.

The compiler uses a variety of heuristics to determine whether or not to inline a function. For example, the compiler takes into account the size of the function being inlined and the amount of inlining that has already been done in the current function. Therefore, seemingly insignificant changes in the source program can cause the warnings produced by -Winline to appear or disappear.

-Wmain

-Wno-main

Warn if the type of main is suspicious. main should be a function with external linkage, returning int, taking either zero arguments, two, or three arguments of appropriate types. This warning is enabled by -Wall.

-Wmissing-braces

-Wno-missing-braces

Warn if an aggregate or union initializer is not fully bracketed. In the following example, the initializer for a is not fully bracketed, but that for b is fully bracketed.

 int a[2][2] = { 0, 1, 2, 3 };
 int b[2][2] = { { 0, 1 }, { 2, 3 } };

This warning is enabled by -Wall.

-Wmissing-declarations

-Wno-missing-declarations

Warn if a global function is defined without a previous declaration. Do so even if the definition itself provides a prototype. Use this option to detect global functions that are not declared in header files.

-Wmissing-format-attribute

-Wno-missing-format-attribute

Warn about function pointers which might be candidates for format attributes. Note these are only possible candidates, not absolute ones. The compiler will guess that function pointers with format attributes that are used in assignment, initialization, parameter passing or return statements should have a corresponding format attribute in the resulting type. That is: the left-hand side of the assignment or initialization, the type of the parameter variable, or the return type of the containing function respectively should also have a format attribute to avoid the warning.

The compiler will also warn about function definitions which might be candidates for format attributes. Again, these are only possible candidates. The compiler will guess that format attributes might be appropriate for any function that calls a function like vprintf or vscanf, but this might not always be the case, and some functions for which format attributes are appropriate may not be detected.

-Wmissing-noreturn

-Wno-missing-noreturn

Warn about functions which might be candidates for attribute noreturn. Note these are only possible candidates, not absolute ones. Care should be taken to manually verify functions actually do not ever return before adding the noreturn attribute, otherwise subtle code generation bugs could be introduced. You will not get a warning for main in hosted C environments.

-Wmissing-prototypes

-Wno-missing-prototypes

Warn if a global function is defined without a previous prototype declaration. This warning is issued even if the definition itself provides a prototype. The aim is to detect global functions that fail to be declared in header files.

-Wmultichar

-Wno-multichar

Do not warn if a multicharacter constant is used. Usually they indicate a typo in the user's code, as they have implementation-defined values, and should not be used in portable code.

-Wnested-externs

-Wno-nested-externs

Warn if an extern declaration is encountered within a function.

-Wno-cast-qual

Do not warn whenever a pointer is cast so as to remove a type qualifier from the target type. For example, warn if a const char * is cast to an ordinary char *.

-Wno-format-extra-args

If -Wformat is specified, do not warn about excess arguments to a printf or scanf format function. The C standard specifies that such arguments are ignored.

Where the unused arguments lie between used arguments that are specified with $ operand number specifications, normally warnings are still given, since the implementation could not know what type to pass to va_arg to skip the unused arguments. However, in the case of scanf formats, this option will suppress the warning if the unused arguments are all pointers, since the Single Unix Specification says that such unused arguments are allowed.

-Wno-format-y2k

If -Wformat is specified, do not warn about strftime formats which may yield only a two-digit year.

-Wlong-long

-Wno-long-long

Warn if long long type is used. This is default. To inhibit the warning messages, use -Wno-long-long. Flags -Wlong-long and -Wno-long-long are taken into account only when -pedantic flag is used.

-Wnonnull

Warn about passing a null pointer for arguments marked as requiring a non-null value by the nonnull function attribute.

-Wnonnull is included in -Wall and -Wformat.

-Wno-non-template-friend

Disable warnings when non-templatized friend functions are declared within a template. Since the advent of explicit template specification support in pathCC, if the name of the friend is an unqualified-id (i.e., friend foo(int)), the C++ language specification demands that the friend declare or define an ordinary, nontemplate function. Before pathCC implemented explicit specification, unqualified-ids could be interpreted as a particular specialization of a templatized function. Because this non-conforming behavior is no longer the default behavior for pathCC, -Wno-non-template-friend is off by default allowing the compiler to check existing code for potential trouble spots.

-Wnon-virtual-dtor

-Wno-non-virtual-dtor

Warn when a class appears to be polymorphic, thereby requiring a virtual destructor, yet it declares a non-virtual one. This warning is also enabled if -Weffc++ is specified.

-Wno-pmf-conversions

Disable the diagnostic for converting a bound pointer to member function to a plain pointer.

-Wold-style-cast

-Wno-old-style-cast

Warn if an old-style (C-style) cast to a non-void type is used within a C++ program. The new-style casts (dynamic_cast, static_cast, reinterpret_cast, and const_cast) are less vulnerable to unintended effects and much easier to search for.

-Woverloaded-virtual

-Wno-overloaded-virtual

Warn when a function declaration hides virtual functions from a base class. For example, in:

 struct A {
 virtual void f();
 };
 
 struct B: public A {
 void f(int);
 };

the A class version of f is hidden in B, and code like:

 B* b;
 b->f();

will fail to compile.

-Wpacked

-Wno-packed

Warn if a structure is given the packed attribute, but the packed attribute has no effect on the layout or size of the structure. Such structures may be mis-aligned for little benefit. For instance, in this code, the variable f.x in struct bar will be misaligned even though struct bar does not itself have the packed attribute:

 struct foo {
 int x;
 char a, b, c, d;
 } __attribute__((packed));
 struct bar {
 char z;
 struct foo f;
 };

-Wpadded

-Wno-padded

Warn if padding is included in a structure, either to align an element of the structure or to align the whole structure. Sometimes when this happens it is possible to rearrange the fields of the structure to reduce the padding and so make the structure smaller.

-Wparentheses

-Wno-parentheses

Warn if parentheses are omitted in certain contexts, such as when there is an assignment in a context where a truth value is expected, or when operators are nested whose precedence people often get confused about. Only the warning for an assignment used as a truth value is supported when compiling C++; the other warnings are only supported when compiling C.

Also warn if a comparison like x<=y<=z appears; this is equivalent to (x<=y ? 1 : 0) <= z, which is a different interpretation from that of ordinary mathematical notation.

Also warn about constructions where there may be confusion as to which if statement an else branch belongs. Here is an example of such a case:

 {
 if (a)
 if (b)
 foo ();
 else
 bar ();
 }

In C, every else branch belongs to the innermost possible if statement, which in this example is if (b). This is often not what the programmer expected, as illustrated in the above example by indentation the programmer chose. When there is the potential for this confusion, the compiler will issue a warning when this flag is specified. To eliminate the warning, add explicit braces around the innermost if statement so there is no way the else could belong to the enclosing if. The resulting code would look like this:

 {
 if (a)
 {
 if (b)
 foo ();
 else
 bar ();
 }
 }

This warning is enabled by -Wall.

-Wpointer-arith

-Wno-pointer-arith

Warn about anything that depends on the “size of” a function type or of void. GNU C assigns these types a size of 1, for convenience in calculations with void * pointers and pointers to functions.

-Wredundant-decls

-Wno-redundant-decls

Warn if anything is declared more than once in the same scope, even in cases where multiple declaration is valid and changes nothing.

-Wreorder

-Wno-reorder

Warn when the order of member initializers given in the code does not match the order in which they must be executed. For instance:

 struct A {
 int i;
 int j;
 A(): j (0), i (1) { }
 };

The compiler will rearrange the member initializers for i and j to match the declaration order of the members, emitting a warning to that effect. This warning is enabled by -Wall.

-Wreturn-type

-Wno-return-type

Warn whenever a function is defined with a return-type that defaults to int. Also warn about any return statement with no return-value in a function whose return-type is not void.

For C, also warn if the return type of a function has a type qualifier such as const. Such a type qualifier has no effect, since the value returned by a function is not an lvalue. ISO C prohibits qualified void return types on function definitions, so such return types always receive a warning even without this option.

For C++, a function without return type always produces a diagnostic message, even when -Wno-return-type is specified. The only exceptions are main and functions defined in system headers.

This warning is enabled by -Wall.

-Wsequence-point

-Wno-sequence-point

Warn about code that may have undefined semantics because of violations of sequence point rules in the C and C++ standards.

The C and C++ standards defines the order in which expressions in a C/C++ program are evaluated in terms of sequence points, which represent a partial ordering between the execution of parts of the program: those executed before the sequence point, and those executed after it. These occur after the evaluation of a full expression (one which is not part of a larger expression), after the evaluation of the first operand of a &&, ||, ? : or , (comma) operator, before a function is called (but after the evaluation of its arguments and the expression denoting the called function), and in certain other places. Other than as expressed by the sequence point rules, the order of evaluation of subexpressions of an expression is not specified. All these rules describe only a partial order rather than a total order, since, for example, if two functions are called within one expression with no sequence point between them, the order in which the functions are called is not specified. However, the standards committee have ruled that function calls do not overlap.

It is not specified when between sequence points modifications to the values of objects take effect. Programs whose behavior depends on this have undefined behavior; the C and C++ standards specify that “Between the previous and next sequence point an object shall have its stored value modified at most once by the evaluation of an expression. Furthermore, the prior value shall be read only to determine the value to be stored.”. If a program breaks these rules, the results on any particular implementation are entirely unpredictable.

Examples of code with undefined behavior are a = a++;, a[n] = b[n++] and a[i++] = i;. Some more complicated cases are not diagnosed by this option, and it may give an occasional false positive result, but in general it has been found fairly effective at detecting this sort of problem in programs.

The standard is worded confusingly, therefore there is some debate over the precise meaning of the sequence point rules in subtle cases. Links to discussions of the problem, including proposed formal definitions, may be found on the GCC readings page, at http://gcc.gnu.org/readings.html.

This warning is enabled by -Wall for C and C++.

-Wshadow

-Wno-shadow

Warn whenever a local variable shadows another local variable, parameter or global variable or whenever a built-in function is shadowed.

-Wsign-compare

-Wno-sign-compare

Warn when a comparison between signed and unsigned values could produce an incorrect result when the signed value is converted to unsigned. This warning is also enabled by -Wextra; to get the other warnings of -Wextra without this warning, use -Wextra -Wno-sign-compare.

-Wsign-promo

-Wno-sign-promo

Warn when overload resolution chooses a promotion from unsigned or enumerated type to a signed type, over a conversion to an unsigned type of the same size. Previous versions of pathCC would try to preserve unsignedness, but the standard mandates the current behavior.

 struct A {
 operator int ();
 A& operator = (int);
 };
 
 main ()
 {
 A a,b;
 a = b;
 }

In this example, G++ will synthesize a default A& operator = (const A&);, while cfront will use the user-defined operator =.

-Wstrict-aliasing

-Wno-strict-aliasing

This option is only active when -fstrict-aliasing is active. It warns about code which might break the strict aliasing rules that the compiler is using for optimization. The warning does not catch all cases, but does attempt to catch the more common pitfalls. It is included in -Wall.

-Wstrict-prototypes

-Wnostrict-prototypes

Warn if a function is declared or defined without specifying the argument types. (An old-style function definition is permitted without a warning if preceded by a declaration which specifies the argument types.)

-Wswitch

-Wno-switch

Warn whenever a switch statement has an index of enumerated type and lacks a case for one or more of the named codes of that enumeration. (The presence of a default label prevents this warning.) case labels outside the enumeration range also provoke warnings when this option is used. This warning is enabled by -Wall.

-Wswitch-default

Warn whenever a switch statement does not have a default case.

-Wswitch-enum

Warn whenever a switch statement has an enumerated type and lacks a case for one or more of the named codes of that enumeration.

-Wsystem-headers

-Wno-system-headers

Print warning messages for constructs found in system header files. Warnings from system headers are normally suppressed, on the assumption that they usually do not indicate real problems and would only make the compiler output harder to read. Using this command line option tells pathCC to emit warnings from system headers as if they occurred in user code. However, note that using -Wall in conjunction with this option will not warn about unknown pragmas in system headers—for that, -Wunknown-pragmas must also be used.

-Wsynth (C++ Only)

-Wno-synth (C++ Only)

-Wsynth warns about synthesis that is not backward compatible with cfront. -Wno-synth suppress warnings about systhesis that is not backward compatible with cfront.

-Wtraditional

-Wno-traditional

Warn about certain constructs that behave differently in traditional and ISO C. Also warn about ISO C constructs that have no traditional C equivalent, and/or problematic constructs which should be avoided.

Macro parameters that appear within string literals in the macro body. In traditional C macro replacement takes place within string literals, but does not in ISO C.
In traditional C, some preprocessor directives did not exist. Traditional preprocessors would only consider a line to be a directive if the # appeared in column 1 on the line. Therefore -Wtraditional warns about directives that traditional C understands but would ignore because the # does not appear as the first character on the line. It also suggests you hide directives like #pragma not understood by traditional C by indenting them. Some traditional implementations would not recognize #elif, so it suggests avoiding it altogether.
A function-like macro that appears without arguments.
The unary plus operator.
The U integer constant suffix, or the F or L floating point constant suffixes. (Traditional C does support the L suffix on integer constants.) Note, these suffixes appear in macros defined in the system headers of most modern systems, e.g. the _MIN/_MAX macros in <limits.h>. Use of these macros in user code might normally lead to spurious warnings, however the integrated preprocessor has enough context to avoid warning in these cases.
A function declared external in one block and then used after the end of the block.
A switch statement has an operand of type long.
A non-static function declaration follows a static one. This construct is not accepted by some traditional C compilers.
The ISO type of an integer constant has a different width or signedness from its traditional type. This warning is only issued if the base of the constant is ten. I.e. hexadecimal or octal values, which typically represent bit patterns, are not warned about.
Usage of ISO string concatenation is detected.
Initialization of automatic aggregates.
Identifier conflicts with labels. Traditional C lacks a separate namespace for labels.
Initialization of unions. If the initializer is zero, the warning is omitted. This is done under the assumption that the zero initializer in user code appears conditioned on e.g. __STDC__ to avoid missing initializer warnings and relies on default initialization to zero in the traditional C case.
Conversions by prototypes between fixed/floating point values and vice versa. The absence of these prototypes when compiling with traditional C would cause serious problems. This is a subset of the possible conversion warnings, for the full set use -Wconversion.
Use of ISO C style function definitions. This warning intentionally is not issued for prototype declarations or variadic functions because these ISO C features will appear in your code when using libiberty's traditional C compatibility macros, PARAMS and VPARAMS. This warning is also bypassed for nested functions because that feature is already an extension and thus not relevant to traditional C compatibility.

-Wtrigraphs

-Wno-trigraphs

Warn if any trigraphs are encountered that might change the meaning of the program (trigraphs within comments are not warned about). This warning is enabled by -Wall.

Previous: Warning Options, Up: Invoking Path64

3.18 Environment Variables Affecting x86 Path64

This section describes several environment variables that affect how the compiler operates. System environment variables can be used to affect the behavior of the x86 Path64 compilers. The following lists all such environment variables recognized by the compilers.

3.18.1 Environment Variables for the C/C++ Compiler

Path64_CFLAGS: Compilation flags to be passed to the C compiler (pathcc).
Path64_CXXFLAGS: Compilation flags to be passed to the C++ compiler (pathCC).

3.18.2 Environment Variables for the Fortran Compiler

F90_BOUNDS_CHECK_ABORT: Instruct the program to abort upon encountering the first bounds check violation.
F90_DUMP_MAP: Dump memory mapping information when a segmentation fault occurs.
FTN_SUPPRESS_REPEATS: Instead of using the repeat factor, output multiple values at run time.
NLSPATH: Specify the location of compile-time and run-time error messages. (You can use %N to denote the base name of the file.) This environment variable is useful if the main function of your program is coded in C, and other parts of the program are coded in Fortran. In this case, NLSPATH tells the Fortran run time library where to find the file containing the run time error messages.
Path64_FDEBUG_ALLOC: Initialize memory locations during program execution. This environment variable is used to debug Fortran memory allocations.
Path64_FFLAGS: Compilation flags to be passed to the Fortran compiler (openf90, pathf95).

3.18.3 Language-independent Environment Variables

FILENV: Specify the location of the assign file.
HUGETLB_ELF_LIMIT: Specify the maximum number of huge pages to be used for bdt (bss, data, and text segments).
HUGETLB_LIMIT: Specify the maximum number of huge pages to be used for the heap.
Path64_COMPILER_DEFAULTS_PATH: Specify a directory or a list of directories to search for the compiler.defaults file.
Path64_GENFLAGS: Compilation flags to be passed to all compilers.
Path64_PROBLEM_REPORT_DIR: Specify a directory into which the compiler can save preprocessed source files and problem reports in the event the compiler encounters an internal error.

3.18.4 Environment Variables for OpenMP

OMP_DYNAMIC: Specify whether dynamic adjustment of the number of threads available for execution is to be enabled.
OMP_NESTED: Specify whether nested parallelism is to be enabled.
OMP_NUM_THREADS: Specify the number of threads to be used during execution.
OMP_SCHEDULE: Specify the schedule type to be applied to DO and PARALLEL_DO directives with RUNTIME schedule type. OMP_SCHEDULE can be any of STATIC, DYNAMIC, or GUIDED.
OMP_SLAVE_STACK_SIZE: Specify the amount of stack size to be used for slave threads.

Next: Funding, Previous: Invoking Path64, Up: Top

4 Binary Compatibility

Binary compatibility encompasses several related concepts:

application binary interface (ABI): The set of runtime conventions followed by all of the tools that deal with binary representations of a program, including compilers, assemblers, linkers, and language runtime support. Some ABIs are formal with a written specification, possibly designed by multiple interested parties. Others are simply the way things are actually done by a particular set of tools.
ABI conformance: A compiler conforms to an ABI if it generates code that follows all of the specifications enumerated by that ABI. A library conforms to an ABI if it is implemented according to that ABI. An application conforms to an ABI if it is built using tools that conform to that ABI and does not contain source code that specifically changes behavior specified by the ABI.
calling conventions: Calling conventions are a subset of an ABI that specify how arguments are passed and function results are returned.
interoperability: Different sets of tools are interoperable if they generate files that can be used in the same program. The set of tools includes compilers, assemblers, linkers, libraries, header files, startup files, and debuggers. Binaries produced by different sets of tools are not interoperable unless they implement the same ABI. This applies to different versions of the same tools as well as tools from different vendors.
intercallability: Whether a function in a binary built by one set of tools can call a function in a binary built by a different set of tools is a subset of interoperability.
implementation-defined features: Language standards include lists of implementation-defined features whose behavior can vary from one implementation to another. Some of these features are normally covered by a platform's ABI and others are not. The features that are not covered by an ABI generally affect how a program behaves, but not intercallability.
compatibility: Conformance to the same ABI and the same behavior of implementation-defined features are both relevant for compatibility.

The application binary interface implemented by a C or C++ compiler affects code generation and runtime support for:

size and alignment of data types
layout of structured types
calling conventions
register usage conventions
interfaces for runtime arithmetic support
object file formats

In addition, the application binary interface implemented by a C++ compiler affects code generation and runtime support for:

name mangling
exception handling
invoking constructors and destructors
layout, alignment, and padding of classes
layout and alignment of virtual tables

Some x86 Path64 compilation options cause the compiler to generate code that does not conform to the platform's default ABI. Other options cause different program behavior for implementation-defined features that are not covered by an ABI. These options are provided for consistency with other compilers that do not follow the platform's default ABI or the usual behavior of implementation-defined features for the platform. Be very careful about using such options.

Most platforms have a well-defined ABI that covers C code, but ABIs that cover C++ functionality are not yet common.

Starting with x86 Path64 4.2, the Path64 binary conventions for C++ are based on a written, vendor-neutral C++ ABI that was designed to be specific to x86-64 platforms but also includes generic specifications that apply to any i386 platform. This C++ ABI is also implemented by other compiler vendors on some platforms, notably GNU/Linux® and BSD systems. We have tried hard to provide a stable ABI that will be compatible with future GCC i386 and x86-64 releases, but it is possible that we will encounter problems that make this difficult. Such problems could include different interpretations of the C++ ABI by different vendors, bugs in the ABI, or bugs in the implementation of the ABI in different compilers.

The C++ library used with a C++ compiler includes the Standard C++ Library, with functionality defined in the C++ Standard, plus language runtime support. The runtime support is included in a C++ ABI, but there is no formal ABI for the Standard C++ Library. Two implementations of that library are interoperable if one follows the de-facto ABI of the other and if they are both built with the same compiler, or with compilers that conform to the same ABI for C++ compiler and runtime support.

When x86 Path64 and another C++ compiler conform to the same C++ ABI, but the implementations of the Standard C++ Library that they normally use do not follow the same ABI for the Standard C++ Library, object files built with those compilers can be used in the same program only if they use the same C++ library. This requires specifying the location of the C++ library header files when invoking the compiler whose usual library is not being used. The location of the x86 Path64 C++ header files depends on how the x86 Path64 build was configured, but can be seen by using the x86 Path64 -v option. With default configuration options for x86 Path64 4.2 the compile line for a different C++ compiler needs to include

 -IPath64_install_directory/include/c++/4.2

Similarly, compiling code with x86 Path64 that must use a C++ library other than the GNU C++ library requires specifying the location of the header files for that other library.

The most straightforward way to link a program to use a particular C++ library is to use a C++ driver that specifies that C++ library by default. The pathCC driver, for example, tells the linker where to find the Path64 C++ library (libstdc++) plus the other libraries and startup files it needs, in the proper order.

If a program must use a different C++ library and it's not possible to do the final link using a C++ driver that uses that library by default, it is necessary to tell pathCC the location and name of that library. It might also be necessary to specify different startup files and other runtime support libraries, and to suppress the use of the Path64 support libraries with one or more of the options -nostdlib, -nostartfiles, and -nodefaultlibs.

Next: Copying, Previous: Compatibility, Up: Top

Funding Free Software

If you want to have more free software a few years from now, it makes sense for you to help encourage people to contribute funds for its development. The most effective approach known is to encourage commercial redistributors to donate.

Users of free software systems can boost the pace of development by encouraging for-a-fee distributors to donate part of their selling price to free software developers—the Free Software Foundation, and others.

The way to convince distributors to do this is to demand it and expect it from them. So when you compare distributors, judge them partly by how much they give to free software development. Show distributors they must compete to be the one who gives the most.

To make this approach work, you must insist on numbers that you can compare, such as, “We will donate ten dollars to the Frobnitz project for each disk sold.” Don't be satisfied with a vague promise, such as “A portion of the profits are donated,” since it doesn't give a basis for comparison.

Even a precise fraction “of the profits from this disk” is not very meaningful, since creative accounting and unrelated business decisions can greatly alter what fraction of the sales price counts as profit. If the price you pay is $50, ten percent of the profit is probably less than a dollar; it might be a few cents, or nothing at all.

Some redistributors do development work themselves. This is useful too; but to keep everyone honest, you need to inquire how much they do, and what kind. Some kinds of development make much more long-term difference than others. For example, maintaining a separate version of a program contributes very little; maintaining the standard version of a program for the whole community contributes much. Easy new ports contribute little, since someone else would surely do them; difficult ports such as adding a new CPU to the GNU Compiler Collection contribute more; major new features or packages contribute the most.

By establishing the idea that supporting further development is “the proper thing to do” when distributing free software for a fee, we can assure a steady flow of resources into making more free software.

 
 Copyright © 1994 Free Software Foundation, Inc.
 Verbatim copying and redistribution of this section is permitted
 without royalty; alteration is not permitted.

Next: GNU Free Documentation License, Previous: Funding, Up: Top

GNU GENERAL PUBLIC LICENSE

Version 2, June 1991

 Copyright © 1989, 1991 Free Software Foundation, Inc.
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

Preamble

The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software—to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Library General Public License instead.) You can apply it to your programs, too.

When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.

To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it.

For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.

We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software.

Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations.

Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all.

The precise terms and conditions for copying, distribution and modification follow.

TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The “Program”, below, refers to any such program or work, and a “work based on the Program” means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term “modification”.) Each licensee is addressed as “you”.
Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does.
You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program.
You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.
You may modify your copy or copies of the Program or any portion of it, thus forming a work based on the Program, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions:
1. You must cause the modified files to carry prominent notices stating that you changed the files and the date of any change.
2. You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.
3. If the modified program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the most ordinary way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this License. (Exception: if the Program itself is interactive but does not normally print such an announcement, your work based on the Program is not required to print an announcement.)
These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.

In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.
You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following:
1. Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
2. Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding source code, to be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
3. Accompany it with the information you received as to the offer to distribute corresponding source code. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with Subsection b above.)
The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.

If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code.
You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.
You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it.
Each time you redistribute the Program (or any work based on the Program), the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions. You may not impose any further restrictions on the recipients' exercise of the rights granted herein. You are not responsible for enforcing compliance by third parties to this License.
If, as a consequence of a court judgment or allegation of patent infringement or for any other reason (not limited to patent issues), conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program.
If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances.

It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.

This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.
If the distribution and/or use of the Program is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Program under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License.
The Free Software Foundation may publish revised and/or new versions of the General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and “any later version”, you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation.
If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally.
NO WARRANTY
BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

END OF TERMS AND CONDITIONS

Appendix: How to Apply These Terms to Your New Programs

If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.

To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.

 one line to give the program's name and a brief idea of what it does.
 Copyright (C) year name of author
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA

Also add information on how to contact you by electronic and paper mail.

If the program is interactive, make it output a short notice like this when it starts in an interactive mode:

 Gnomovision version 69, Copyright (C) year name of author
 Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
 type `show w'.
 This is free software, and you are welcome to redistribute it
 under certain conditions; type `show c' for details.

The hypothetical commands show w and show c should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than show w and show c; they could even be mouse-clicks or menu items—whatever suits your program.

You should also get your employer (if you work as a programmer) or your school, if any, to sign a “copyright disclaimer” for the program, if necessary. Here is a sample; alter the names:

 Yoyodyne, Inc., hereby disclaims all copyright interest in the program
 `Gnomovision' (which makes passes at compilers) written by James Hacker.
 
 signature of Ty Coon, 1 April 1989
 Ty Coon, President of Vice

This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.

Next: Option Index, Previous: Copying, Up: Top

GNU Free Documentation License

Version 1.2, November 2002

 Copyright © 2000,2001,2002 Free Software Foundation, Inc.
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

PREAMBLE
The purpose of this License is to make a manual, textbook, or other functional and useful document free in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.
APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document”, below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you”. You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.

A “Modified Version” of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.

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The “Title Page” means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title Page” means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text.

A section “Entitled XYZ” means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.

The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.
VERBATIM COPYING
You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above, and you may publicly display copies.
COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.
MODIFICATIONS
You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:
1. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
2. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
3. State on the Title page the name of the publisher of the Modified Version, as the publisher.
4. Preserve all the copyright notices of the Document.
5. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
6. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
7. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice.
8. Include an unaltered copy of this License.
9. Preserve the section Entitled “History”, Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
10. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
11. For any section Entitled “Acknowledgements” or “Dedications”, Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
13. Delete any section Entitled “Endorsements”. Such a section may not be included in the Modified Version.
14. Do not retitle any existing section to be Entitled “Endorsements” or to conflict in title with any Invariant Section.
15. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles.

You may add a section Entitled “Endorsements”, provided it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.
COMBINING DOCUMENTS
You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You must delete all sections Entitled “Endorsements.”
COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.
AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.
TRANSLATION
Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.
TERMINATION
You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.
FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.

ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page:

 Copyright (C) year your name.
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.2
 or any later version published by the Free Software Foundation;
 with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
 Texts. A copy of the license is included in the section entitled ``GNU
 Free Documentation License''.

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this:

 with the Invariant Sections being list their titles, with
 the Front-Cover Texts being list, and with the Back-Cover Texts
 being list.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.

Next: Keyword Index, Previous: GNU Free Documentation License, Up: Top

Option Index

Path64's command line options are indexed here without any initial - or --. Where an option has both positive and negative forms (such as -foption and -fno-option), relevant entries in the manual are indexed under the most appropriate form; it may sometimes be useful to look up both forms.

Previous: Option Index, Up: Top

Keyword Index

Footnotes

[1] On some systems, gcc -shared needs to build supplementary stub code for constructors to work. On multi-libbed systems, gcc -shared must select the correct support libraries to link against. Failing to supply the correct flags may lead to subtle defects. Supplying them in cases where they are not necessary is innocuous.

Path64

End User Documentation

Using the x86 Path64 Compiler Suite

Short Contents

Table of Contents

Introduction

1 The x86 Path64 Compilers

1.1 Programming Languages Supported

1.2 Language Standards Supported

1.3 How To Get Help

1.4 Reporting Bugs

1.4.1 Have You Found a Bug?

1.4.2 How and where to Report Bugs

1.5 Contributing to Path64 Development

2 Using the x86 Path64 Compiler

2.1 The x86 Path64 C/C++ Compiler

2.1.1 Using the C/C++ Compiler

2.1.2 Pre-defined Macros

2.2 The x86 Path64 Fortran Compiler

2.2.1 Using the Fortran compiler

2.2.2 Pre-defined macros

2.2.3 Fortran Modules

3 x86 Path64 Command Options

3.1 Option Summary

3.2 Options Controlling the Kind of Output

3.3 Options for Directory Search

3.4 Compiling C++ Programs

3.5 Options Controlling C/C++ Dialect

3.6 Options Controlling Fortran Dialect

3.7 Options to Control Language Features

3.8 Options which are Language Independent

3.9 Options That Control Optimization

3.9.1 Options that Control Feedback Directed Optimizations

3.9.2 Options that Control Global Optimizations

3.9.3 Options that Control General Optimizations

3.9.4 Options that Control Interprocedural Optimizations

3.9.5 Options that Control Loop Nest Optimizations

3.10 Options Controlling the Preprocessor

3.11 Passing Options to the Assembler

3.12 Options Controlling the Linker and Libraries

3.13 Options for Code Generation Conventions

3.14 Specifying Target Environment and Machine

3.14.1 Hardware Models and Configurations

3.15 Options to Control Diagnostic

3.16 Options for Debugging Your Program

3.17 Options to Request or Suppress Warnings

3.17.1 Options that Control Language Independent Warnings

3.17.2 Options that Control C/C++ Warnings

3.18 Environment Variables Affecting x86 Path64

3.18.1 Environment Variables for the C/C++ Compiler

3.18.2 Environment Variables for the Fortran Compiler

3.18.3 Language-independent Environment Variables

3.18.4 Environment Variables for OpenMP

4 Binary Compatibility

Funding Free Software

GNU GENERAL PUBLIC LICENSE

Preamble

Appendix: How to Apply These Terms to Your New Programs

GNU Free Documentation License

ADDENDUM: How to use this License for your documents

Option Index

Keyword Index

Footnotes

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