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author | ru <ru@FreeBSD.org> | 2006-09-21 07:55:28 +0000 |
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committer | ru <ru@FreeBSD.org> | 2006-09-21 07:55:28 +0000 |
commit | f928d7c5b7d569a937577c848b265c54e49f1d3d (patch) | |
tree | 2d84f5da5a26cfc5bd4a6a0946130a4501e05504 /contrib/gcc/gcc.1 | |
parent | 27cbd2a492cac9b35c1a1e74f4bb52926dc4a4c0 (diff) | |
download | FreeBSD-src-f928d7c5b7d569a937577c848b265c54e49f1d3d.zip FreeBSD-src-f928d7c5b7d569a937577c848b265c54e49f1d3d.tar.gz |
Removed these from HEAD as well.
Diffstat (limited to 'contrib/gcc/gcc.1')
-rw-r--r-- | contrib/gcc/gcc.1 | 4272 |
1 files changed, 0 insertions, 4272 deletions
diff --git a/contrib/gcc/gcc.1 b/contrib/gcc/gcc.1 deleted file mode 100644 index b510409..0000000 --- a/contrib/gcc/gcc.1 +++ /dev/null @@ -1,4272 +0,0 @@ -.\" $FreeBSD$ -.\" Copyright (c) 1991, 1992, 1993, 1994 Free Software Foundation -*-Text-*- -.\" See section COPYING for conditions for redistribution -.\" -.\" Set up \*(lq, \*(rq if -man hasn't already set it up. -.if @@\*(lq@ \{\ -. ds lq " -. if t .ds lq `` -. if !@@\(lq@ .ds lq "\(lq -.\} -.if @@\*(rq@ \{\ -. ds rq " -. if t .ds rq '' -. if !@@\(rq@ .ds rq "\(rq -.\} -.de Id -.ds Rv \\$3 -.ds Dt \\$4 -.. -.de Sp -.if n .sp -.if t .sp 0.4 -.. -.Id $Id: gcc.1,v 1.9 1998/12/16 20:55:57 law Exp $ -.TH GCC 1 "\*(Dt" "GNU Tools" "GNU Tools" -.SH NAME -gcc, g++ \- GNU project C and C++ Compiler -.SH SYNOPSIS -.B gcc -.RI "[ " option " | " filename " ].\|.\|." -.br -.B g++ -.RI "[ " option " | " filename " ].\|.\|." -.SH WARNING -The information in this man page is an extract from the full -documentation of the GNU C compiler, and is limited to the meaning of -the options. -.PP -This man page is not kept up to date except when volunteers want to -maintain it. If you find a discrepancy between the man page and the -software, please check the Info file, which is the authoritative -documentation. -.PP -If we find that the things in this man page that are out of date cause -significant confusion or complaints, we will stop distributing the man -page. The alternative, updating the man page when we update the Info -file, is impossible because the rest of the work of maintaining GNU CC -leaves us no time for that. The GNU project regards man pages as -obsolete and should not let them take time away from other things. -.PP -For complete and current documentation, refer to the Info file `\|\c -.B gcc\c -\&\|' or the manual -.I -Using and Porting GNU CC (for version 2.0)\c -\&. Both are made from the Texinfo source file -.BR gcc.texinfo . -.SH DESCRIPTION -The C and C++ compilers are integrated. Both process input files -through one or more of four stages: preprocessing, compilation, -assembly, and linking. Source filename suffixes identify the source -language, but which name you use for the compiler governs default -assumptions: -.TP -.B gcc -assumes preprocessed (\c -.B .i\c -\&) files are C and assumes C style linking. -.TP -.B g++ -assumes preprocessed (\c -.B .i\c -\&) files are C++ and assumes C++ style linking. -.PP -Suffixes of source file names indicate the language and kind of -processing to be done: -.Sp -.nf -.ta \w'\fB.cxx\fP 'u -\&\fB.c\fP C source; preprocess, compile, assemble -\&\fB.C\fP C++ source; preprocess, compile, assemble -\&\fB.cc\fP C++ source; preprocess, compile, assemble -\&\fB.cxx\fP C++ source; preprocess, compile, assemble -\&\fB.m\fP Objective-C source; preprocess, compile, assemble -\&\fB.i\fP preprocessed C; compile, assemble -\&\fB.ii\fP preprocessed C++; compile, assemble -\&\fB.s\fP Assembler source; assemble -\&\fB.S\fP Assembler source; preprocess, assemble -\&\fB.h\fP Preprocessor file; not usually named on command line -.Sp -.fi -Files with other suffixes are passed to the linker. Common cases include: -.Sp -.nf -\&\fB.o\fP Object file -\&\fB.a\fP Archive file -.br -.fi -.Sp -Linking is always the last stage unless you use one of the -.BR \-c , -.BR \-S , -or -.B \-E -options to avoid it (or unless compilation errors stop the whole -process). For the link stage, all -.B .o -files corresponding to source files, -.B \-l -libraries, unrecognized filenames (including named -.B .o -object files and -.B .a -archives) -are passed to the linker in command-line order. -.SH OPTIONS -Options must be separate: `\|\c -.B \-dr\c -\&\|' is quite different from `\|\c -.B \-d \-r -\&\|'. -.PP -Most `\|\c -.B \-f\c -\&\|' and `\|\c -.B \-W\c -\&\|' options have two contrary forms: -.BI \-f name -and -.BI \-fno\- name\c -\& (or -.BI \-W name -and -.BI \-Wno\- name\c -\&). Only the non-default forms are shown here. -.PP -Here is a summary of all the options, grouped by type. Explanations are -in the following sections. -.hy 0 -.na -.TP -.B Overall Options -.br -\-c -\-S -\-E -.RI "\-o " file -\-pipe -\-v -.RI "\-x " language -.TP -.B Language Options -\-ansi -\-fall\-virtual -\-fcond\-mismatch -\-fdollars\-in\-identifiers -\-fenum\-int\-equiv -\-fexternal\-templates -\-fno\-asm -\-fno\-builtin -\-fhosted -\-fno\-hosted -\-ffreestanding -\-fno\-freestanding -\-fno\-strict\-prototype -\-fsigned\-bitfields -\-fsigned\-char -\-fthis\-is\-variable -\-funsigned\-bitfields -\-funsigned\-char -\-fwritable\-strings -\-traditional -\-traditional\-cpp -\-trigraphs -.TP -.B Warning Options -\-fsyntax\-only -\-pedantic -\-pedantic\-errors -\-w -\-W -\-Wall -\-Waggregate\-return -\-Wcast\-align -\-Wcast\-qual -\-Wchar\-subscript -\-Wcomment -\-Wconversion -\-Wenum\-clash -\-Werror -\-Wformat -.RI \-Wid\-clash\- len -\-Wimplicit -\-Wimplicit\-int -\-Wimplicit\-function\-declaration -\-Winline -\-Wlong\-long -\-Wmain -\-Wmissing\-prototypes -\-Wmissing\-declarations -\-Wnested\-externs -\-Wno\-import -\-Wparentheses -\-Wpointer\-arith -\-Wredundant\-decls -\-Wreturn\-type -\-Wshadow -\-Wstrict\-prototypes -\-Wswitch -\-Wtemplate\-debugging -\-Wtraditional -\-Wtrigraphs -\-Wuninitialized -\-Wunused -\-Wwrite\-strings -.TP -.B Debugging Options -\-a -.RI \-d letters -\-fpretend\-float -\-g -.RI \-g level -\-gcoff -\-gxcoff -\-gxcoff+ -\-gdwarf -\-gdwarf+ -\-gstabs -\-gstabs+ -\-ggdb -\-p -\-pg -\-save\-temps -.RI \-print\-file\-name= library -\-print\-libgcc\-file\-name -.RI \-print\-prog\-name= program -.TP -.B Optimization Options -\-fcaller\-saves -\-fcse\-follow\-jumps -\-fcse\-skip\-blocks -\-fdelayed\-branch -\-felide\-constructors -\-fexpensive\-optimizations -\-ffast\-math -\-ffloat\-store -\-fforce\-addr -\-fforce\-mem -\-finline\-functions -\-fkeep\-inline\-functions -\-fmemoize\-lookups -\-fno\-default\-inline -\-fno\-defer\-pop -\-fno\-function\-cse -\-fno\-inline -\-fno\-peephole -\-fomit\-frame\-pointer -\-frerun\-cse\-after\-loop -\-fschedule\-insns -\-fschedule\-insns2 -\-fstrength\-reduce -\-fthread\-jumps -\-funroll\-all\-loops -\-funroll\-loops -\-O -\-O2 -\-O3 -\-O0 -\-Os -.TP -.B Preprocessor Options -.RI \-A assertion -\-C -\-dD -\-dM -\-dN -.RI \-D macro [\|= defn \|] -\-E -\-H -.RI "\-idirafter " dir -.RI "\-include " file -.RI "\-imacros " file -.RI "\-iprefix " file -.RI "\-iwithprefix " dir -\-M -\-MD -\-MM -\-MMD -\-nostdinc -\-P -.RI \-U macro -\-undef -.TP -.B Assembler Option -.RI \-Wa, option -.TP -.B Linker Options -.RI \-l library -\-nostartfiles -\-nostdlib -\-static -\-shared -\-symbolic -.RI "\-Xlinker\ " option -.RI \-Wl, option -.RI "\-u " symbol -.TP -.B Directory Options -.RI \-B prefix -.RI \-I dir -\-I\- -.RI \-L dir -.TP -.B Target Options -.RI "\-b " machine -.RI "\-V " version -.TP -.B Configuration Dependent Options -.I M680x0\ Options -.br -\-m68000 -\-m68020 -\-m68020\-40 -\-m68030 -\-m68040 -\-m68881 -\-mbitfield -\-mc68000 -\-mc68020 -\-mfpa -\-mnobitfield -\-mrtd -\-mshort -\-msoft\-float -.Sp -.I VAX Options -.br -\-mg -\-mgnu -\-munix -.Sp -.I SPARC Options -.br -\-mepilogue -\-mfpu -\-mhard\-float -\-mno\-fpu -\-mno\-epilogue -\-msoft\-float -\-msparclite -\-mv8 -\-msupersparc -\-mcypress -.Sp -.I Convex Options -.br -\-margcount -\-mc1 -\-mc2 -\-mnoargcount -.Sp -.I AMD29K Options -.br -\-m29000 -\-m29050 -\-mbw -\-mdw -\-mkernel\-registers -\-mlarge -\-mnbw -\-mnodw -\-msmall -\-mstack\-check -\-muser\-registers -.Sp -.I M88K Options -.br -\-m88000 -\-m88100 -\-m88110 -\-mbig\-pic -\-mcheck\-zero\-division -\-mhandle\-large\-shift -\-midentify\-revision -\-mno\-check\-zero\-division -\-mno\-ocs\-debug\-info -\-mno\-ocs\-frame\-position -\-mno\-optimize\-arg\-area -\-mno\-serialize\-volatile -\-mno\-underscores -\-mocs\-debug\-info -\-mocs\-frame\-position -\-moptimize\-arg\-area -\-mserialize\-volatile -.RI \-mshort\-data\- num -\-msvr3 -\-msvr4 -\-mtrap\-large\-shift -\-muse\-div\-instruction -\-mversion\-03.00 -\-mwarn\-passed\-structs -.Sp -.I RS6000 Options -.br -\-mfp\-in\-toc -\-mno\-fop\-in\-toc -.Sp -.I RT Options -.br -\-mcall\-lib\-mul -\-mfp\-arg\-in\-fpregs -\-mfp\-arg\-in\-gregs -\-mfull\-fp\-blocks -\-mhc\-struct\-return -\-min\-line\-mul -\-mminimum\-fp\-blocks -\-mnohc\-struct\-return -.Sp -.I MIPS Options -.br -\-mcpu=\fIcpu type\fP -\-mips2 -\-mips3 -\-mint64 -\-mlong64 -\-mlonglong128 -\-mmips\-as -\-mgas -\-mrnames -\-mno\-rnames -\-mgpopt -\-mno\-gpopt -\-mstats -\-mno\-stats -\-mmemcpy -\-mno\-memcpy -\-mno\-mips\-tfile -\-mmips\-tfile -\-msoft\-float -\-mhard\-float -\-mabicalls -\-mno\-abicalls -\-mhalf\-pic -\-mno\-half\-pic -\-G \fInum\fP -\-nocpp -.Sp -.I i386 Options -.br -\-m386 -\-m486 -\-mpentium -\-mpentiumpro -\-mno\-486 -\-mcpu=\fIcpu type\fP -\-march=\fIcpu type\fP -\-msoft\-float -\-mrtd -\-mregparm -\-msvr3\-shlib -\-mno\-ieee\-fp -\-mno\-fp\-ret\-in\-387 -\-mfancy\-math\-387 -\-mno\-wide\-multiply -\-mdebug\-addr -\-mno\-move -\-mprofiler\-epilogue -\-reg\-alloc=LIST -.Sp -.I HPPA Options -.br -\-mpa\-risc\-1\-0 -\-mpa\-risc\-1\-1 -\-mkernel -\-mshared\-libs -\-mno\-shared\-libs -\-mlong\-calls -\-mdisable\-fpregs -\-mdisable\-indexing -\-mtrailing\-colon -.Sp -.I i960 Options -.br -\-m\fIcpu-type\fP -\-mnumerics -\-msoft\-float -\-mleaf\-procedures -\-mno\-leaf\-procedures -\-mtail\-call -\-mno\-tail\-call -\-mcomplex\-addr -\-mno\-complex\-addr -\-mcode\-align -\-mno\-code\-align -\-mic\-compat -\-mic2.0\-compat -\-mic3.0\-compat -\-masm\-compat -\-mintel\-asm -\-mstrict\-align -\-mno\-strict\-align -\-mold\-align -\-mno\-old\-align -.Sp -.I DEC Alpha Options -.br -\-mfp\-regs -\-mno\-fp\-regs -\-mno\-soft\-float -\-msoft\-float -.Sp -.I System V Options -.br -\-G -\-Qy -\-Qn -.RI \-YP, paths -.RI \-Ym, dir -.TP -.B Code Generation Options -.RI \-fcall\-saved\- reg -.RI \-fcall\-used\- reg -.RI \-ffixed\- reg -\-finhibit\-size\-directive -\-fnonnull\-objects -\-fno\-common -\-fno\-ident -\-fno\-gnu\-linker -\-fpcc\-struct\-return -\-fpic -\-fPIC -\-freg\-struct\-return -\-fshared\-data -\-fshort\-enums -\-fshort\-double -\-fvolatile -\-fvolatile\-global -\-fverbose\-asm -.ad b -.hy 1 -.SH FreeBSD SPECIFIC OPTIONS -.TP -.BI "\-pthread" -Link a user-threaded process against libc_r instead of libc. -.SH OVERALL OPTIONS -.TP -.BI "\-x " "language" -Specify explicitly the -.I language\c -\& for the following input files (rather than choosing a default based -on the file name suffix) . This option applies to all following input -files until the next `\|\c -.B \-x\c -\&\|' option. Possible values of \c -.I language\c -\& are -`\|\c -.B c\c -\&\|', `\|\c -.B objective\-c\c -\&\|', `\|\c -.B c\-header\c -\&\|', `\|\c -.B c++\c -\&\|', -`\|\c -.B cpp\-output\c -\&\|', `\|\c -.B assembler\c -\&\|', and `\|\c -.B assembler\-with\-cpp\c -\&\|'. -.TP -.B \-x none -Turn off any specification of a language, so that subsequent files are -handled according to their file name suffixes (as they are if `\|\c -.B \-x\c -\&\|' -has not been used at all). -.PP -If you want only some of the four stages (preprocess, compile, -assemble, link), you can use -`\|\c -.B \-x\c -\&\|' (or filename suffixes) to tell \c -.B gcc\c -\& where to start, and -one of the options `\|\c -.B \-c\c -\&\|', `\|\c -.B \-S\c -\&\|', or `\|\c -.B \-E\c -\&\|' to say where -.B gcc\c -\& is to stop. Note that some combinations (for example, -`\|\c -.B \-x cpp\-output \-E\c -\&\|') instruct \c -.B gcc\c -\& to do nothing at all. -.TP -.B \-c -Compile or assemble the source files, but do not link. The compiler -output is an object file corresponding to each source file. -.Sp -By default, GCC makes the object file name for a source file by replacing -the suffix `\|\c -.B .c\c -\&\|', `\|\c -.B .i\c -\&\|', `\|\c -.B .s\c -\&\|', etc., with `\|\c -.B .o\c -\&\|'. Use -.B \-o\c -\& to select another name. -.Sp -GCC ignores any unrecognized input files (those that do not require -compilation or assembly) with the -.B \-c -option. -.TP -.B \-S -Stop after the stage of compilation proper; do not assemble. The output -is an assembler code file for each non-assembler input -file specified. -.Sp -By default, GCC makes the assembler file name for a source file by -replacing the suffix `\|\c -.B .c\c -\&\|', `\|\c -.B .i\c -\&\|', etc., with `\|\c -.B .s\c -\&\|'. Use -.B \-o\c -\& to select another name. -.Sp -GCC ignores any input files that don't require compilation. -.TP -.B \-E -Stop after the preprocessing stage; do not run the compiler proper. The -output is preprocessed source code, which is sent to the -standard output. -.Sp -GCC ignores input files which don't require preprocessing. -.TP -.BI "\-o " file -Place output in file \c -.I file\c -\&. This applies regardless to whatever -sort of output GCC is producing, whether it be an executable file, -an object file, an assembler file or preprocessed C code. -.Sp -Since only one output file can be specified, it does not make sense to -use `\|\c -.B \-o\c -\&\|' when compiling more than one input file, unless you are -producing an executable file as output. -.Sp -If you do not specify `\|\c -.B \-o\c -\&\|', the default is to put an executable file -in `\|\c -.B a.out\c -\&\|', the object file for `\|\c -.I source\c -.B \&.\c -.I suffix\c -\&\c -\&\|' in -`\|\c -.I source\c -.B \&.o\c -\&\|', its assembler file in `\|\c -.I source\c -.B \&.s\c -\&\|', and -all preprocessed C source on standard output. -.TP -.B \-v -Print (on standard error output) the commands executed to run the stages -of compilation. Also print the version number of the compiler driver -program and of the preprocessor and the compiler proper. -.TP -.B \-pipe -Use pipes rather than temporary files for communication between the -various stages of compilation. This fails to work on some systems where -the assembler cannot read from a pipe; but the GNU assembler has -no trouble. -.PP -.SH LANGUAGE OPTIONS -The following options control the dialect of C that the compiler -accepts: -.TP -.B \-ansi -Support all ANSI standard C programs. -.Sp -This turns off certain features of GNU C that are incompatible with -ANSI C, such as the \c -.B asm\c -\&, \c -.B inline\c -\& and \c -.B typeof -keywords, and predefined macros such as \c -.B unix\c -\& and \c -.B vax -that identify the type of system you are using. It also enables the -undesirable and rarely used ANSI trigraph feature, and disallows `\|\c -.B $\c -\&\|' as part of identifiers. -.Sp -The alternate keywords \c -.B _\|_asm_\|_\c -\&, \c -.B _\|_extension_\|_\c -\&, -.B _\|_inline_\|_\c -\& and \c -.B _\|_typeof_\|_\c -\& continue to work despite -`\|\c -.B \-ansi\c -\&\|'. You would not want to use them in an ANSI C program, of -course, but it is useful to put them in header files that might be included -in compilations done with `\|\c -.B \-ansi\c -\&\|'. Alternate predefined macros -such as \c -.B _\|_unix_\|_\c -\& and \c -.B _\|_vax_\|_\c -\& are also available, with or -without `\|\c -.B \-ansi\c -\&\|'. -.Sp -The `\|\c -.B \-ansi\c -\&\|' option does not cause non-ANSI programs to be -rejected gratuitously. For that, `\|\c -.B \-pedantic\c -\&\|' is required in -addition to `\|\c -.B \-ansi\c -\&\|'. -.Sp -The preprocessor predefines a macro \c -.B _\|_STRICT_ANSI_\|_\c -\& when you use the `\|\c -.B \-ansi\c -\&\|' -option. Some header files may notice this macro and refrain -from declaring certain functions or defining certain macros that the -ANSI standard doesn't call for; this is to avoid interfering with any -programs that might use these names for other things. -.TP -.B \-fno\-asm -Do not recognize \c -.B asm\c -\&, \c -.B inline\c -\& or \c -.B typeof\c -\& as a -keyword. These words may then be used as identifiers. You can -use \c -.B _\|_asm_\|_\c -\&, \c -.B _\|_inline_\|_\c -\& and \c -.B _\|_typeof_\|_\c -\& instead. -`\|\c -.B \-ansi\c -\&\|' implies `\|\c -.B \-fno\-asm\c -\&\|'. -.TP -.B \-fno\-builtin -Don't recognize built-in functions that do not begin with two leading -underscores. Currently, the functions affected include \c -.B _exit\c -\&, -.B abort\c -\&, \c -.B abs\c -\&, \c -.B alloca\c -\&, \c -.B cos\c -\&, \c -.B exit\c -\&, -.B fabs\c -\&, \c -.B labs\c -\&, \c -.B memcmp\c -\&, \c -.B memcpy\c -\&, \c -.B sin\c -\&, -.B sqrt\c -\&, \c -.B strcmp\c -\&, \c -.B strcpy\c -\&, and \c -.B strlen\c -\&. -.Sp -The `\|\c -.B \-ansi\c -\&\|' option prevents \c -.B alloca\c -\& and \c -.B _exit\c -\& from -being builtin functions. -.TP -.B \-fhosted -Compile for a hosted environment; this implies the `\|\c -.B \-fbuiltin\c -\&\|' option, and implies that suspicious declarations of -.B main\c -\& should be warned about. -.TP -.B \-ffreestanding -Compile for a freestanding environment; this implies the `\|\c -.B \-fno-builtin\c -\&\|' option, and implies that -.B main\c -\& has no special requirements. -.TP -.B \-fno\-strict\-prototype -Treat a function declaration with no arguments, such as `\|\c -.B int foo -();\c -\&\|', as C would treat it\(em\&as saying nothing about the number of -arguments or their types (C++ only). Normally, such a declaration in -C++ means that the function \c -.B foo\c -\& takes no arguments. -.TP -.B \-trigraphs -Support ANSI C trigraphs. The `\|\c -.B \-ansi\c -\&\|' option implies `\|\c -.B \-trigraphs\c -\&\|'. -.TP -.B \-traditional -Attempt to support some aspects of traditional C compilers. -For details, see the GNU C Manual; the duplicate list here -has been deleted so that we won't get complaints when it -is out of date. -.Sp -But one note about C++ programs only (not C). `\|\c -.B \-traditional\c -\&\|' has one additional effect for C++: assignment to -.B this -is permitted. This is the same as the effect of `\|\c -.B \-fthis\-is\-variable\c -\&\|'. -.TP -.B \-traditional\-cpp -Attempt to support some aspects of traditional C preprocessors. -This includes the items that specifically mention the preprocessor above, -but none of the other effects of `\|\c -.B \-traditional\c -\&\|'. -.TP -.B \-fdollars\-in\-identifiers -Permit the use of `\|\c -.B $\c -\&\|' in identifiers (C++ only). You can also use -`\|\c -.B \-fno\-dollars\-in\-identifiers\c -\&\|' to explicitly prohibit use of -`\|\c -.B $\c -\&\|'. (GNU C++ allows `\|\c -.B $\c -\&\|' by default on some target systems -but not others.) -.TP -.B \-fenum\-int\-equiv -Permit implicit conversion of \c -.B int\c -\& to enumeration types (C++ -only). Normally GNU C++ allows conversion of \c -.B enum\c -\& to \c -.B int\c -\&, -but not the other way around. -.TP -.B \-fexternal\-templates -Produce smaller code for template declarations, by generating only a -single copy of each template function where it is defined (C++ only). -To use this option successfully, you must also mark all files that -use templates with either `\|\c -.B #pragma implementation\c -\&\|' (the definition) or -`\|\c -.B #pragma interface\c -\&\|' (declarations). - -When your code is compiled with `\|\c -.B \-fexternal\-templates\c -\&\|', all -template instantiations are external. You must arrange for all -necessary instantiations to appear in the implementation file; you can -do this with a \c -.B typedef\c -\& that references each instantiation needed. -Conversely, when you compile using the default option -`\|\c -.B \-fno\-external\-templates\c -\&\|', all template instantiations are -explicitly internal. -.TP -.B \-fall\-virtual -Treat all possible member functions as virtual, implicitly. All -member functions (except for constructor functions and -.B new -or -.B delete -member operators) are treated as virtual functions of the class where -they appear. -.Sp -This does not mean that all calls to these member functions will be -made through the internal table of virtual functions. Under some -circumstances, the compiler can determine that a call to a given -virtual function can be made directly; in these cases the calls are -direct in any case. -.TP -.B \-fcond\-mismatch -Allow conditional expressions with mismatched types in the second and -third arguments. The value of such an expression is void. -.TP -.B \-fthis\-is\-variable -Permit assignment to \c -.B this\c -\& (C++ only). The incorporation of -user-defined free store management into C++ has made assignment to -`\|\c -.B this\c -\&\|' an anachronism. Therefore, by default it is invalid to -assign to \c -.B this\c -\& within a class member function. However, for -backwards compatibility, you can make it valid with -`\|\c -.B \-fthis-is-variable\c -\&\|'. -.TP -.B \-funsigned\-char -Let the type \c -.B char\c -\& be unsigned, like \c -.B unsigned char\c -\&. -.Sp -Each kind of machine has a default for what \c -.B char\c -\& should -be. It is either like \c -.B unsigned char\c -\& by default or like -.B signed char\c -\& by default. -.Sp -Ideally, a portable program should always use \c -.B signed char\c -\& or -.B unsigned char\c -\& when it depends on the signedness of an object. -But many programs have been written to use plain \c -.B char\c -\& 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. -.Sp -The type \c -.B char\c -\& is always a distinct type from each of -.B signed char\c -\& and \c -.B unsigned char\c -\&, even though its behavior -is always just like one of those two. -.TP -.B \-fsigned\-char -Let the type \c -.B char\c -\& be signed, like \c -.B signed char\c -\&. -.Sp -Note that this is equivalent to `\|\c -.B \-fno\-unsigned\-char\c -\&\|', which is -the negative form of `\|\c -.B \-funsigned\-char\c -\&\|'. Likewise, -`\|\c -.B \-fno\-signed\-char\c -\&\|' is equivalent to `\|\c -.B \-funsigned\-char\c -\&\|'. -.TP -.B \-fsigned\-bitfields -.TP -.B \-funsigned\-bitfields -.TP -.B \-fno\-signed\-bitfields -.TP -.B \-fno\-unsigned\-bitfields -These options control whether a bitfield is -signed or unsigned, when declared with no explicit `\|\c -.B signed\c -\&\|' or `\|\c -.B unsigned\c -\&\|' qualifier. By default, such a bitfield is -signed, because this is consistent: the basic integer types such as -.B int\c -\& are signed types. -.Sp -However, when you specify `\|\c -.B \-traditional\c -\&\|', bitfields are all unsigned -no matter what. -.TP -.B \-fwritable\-strings -Store string constants in the writable data segment and don't uniquize -them. This is for compatibility with old programs which assume they -can write into string constants. `\|\c -.B \-traditional\c -\&\|' also has this -effect. -.Sp -Writing into string constants is a very bad idea; \*(lqconstants\*(rq should -be constant. -.SH PREPROCESSOR OPTIONS -These options control the C preprocessor, which is run on each C source -file before actual compilation. -.PP -If you use the `\|\c -.B \-E\c -\&\|' option, GCC does nothing except preprocessing. -Some of these options make sense only together with `\|\c -.B \-E\c -\&\|' because -they cause the preprocessor output to be unsuitable for actual -compilation. -.TP -.BI "\-include " "file" -Process \c -.I file\c -\& as input before processing the regular input file. -In effect, the contents of \c -.I file\c -\& are compiled first. Any `\|\c -.B \-D\c -\&\|' -and `\|\c -.B \-U\c -\&\|' options on the command line are always processed before -`\|\c -.B \-include \c -.I file\c -\&\c -\&\|', regardless of the order in which they are -written. All the `\|\c -.B \-include\c -\&\|' and `\|\c -.B \-imacros\c -\&\|' options are -processed in the order in which they are written. -.TP -.BI "\-imacros " file -Process \c -.I file\c -\& as input, discarding the resulting output, before -processing the regular input file. Because the output generated from -.I file\c -\& is discarded, the only effect of `\|\c -.B \-imacros \c -.I file\c -\&\c -\&\|' is to -make the macros defined in \c -.I file\c -\& available for use in the main -input. The preprocessor evaluates any `\|\c -.B \-D\c -\&\|' and `\|\c -.B \-U\c -\&\|' options -on the command line before processing `\|\c -.B \-imacros\c -.I file\c -\&\|', regardless of the order in -which they are written. All the `\|\c -.B \-include\c -\&\|' and `\|\c -.B \-imacros\c -\&\|' -options are processed in the order in which they are written. -.TP -.BI "\-idirafter " "dir" -Add the directory \c -.I dir\c -\& to the second include path. The directories -on the second include path are searched when a header file is not found -in any of the directories in the main include path (the one that -`\|\c -.B \-I\c -\&\|' adds to). -.TP -.BI "\-iprefix " "prefix" -Specify \c -.I prefix\c -\& as the prefix for subsequent `\|\c -.B \-iwithprefix\c -\&\|' -options. -.TP -.BI "\-iwithprefix " "dir" -Add a directory to the second include path. The directory's name is -made by concatenating \c -.I prefix\c -\& and \c -.I dir\c -\&, where \c -.I prefix -was specified previously with `\|\c -.B \-iprefix\c -\&\|'. -.TP -.B \-nostdinc -Do not search the standard system directories for header files. Only -the directories you have specified with `\|\c -.B \-I\c -\&\|' options (and the -current directory, if appropriate) are searched. -.Sp -By using both `\|\c -.B \-nostdinc\c -\&\|' and `\|\c -.B \-I\-\c -\&\|', you can limit the include-file search file to only those -directories you specify explicitly. -.TP -.B \-nostdinc++ -Do not search for header files in the C++\-specific standard directories, -but do still search the other standard directories. -(This option is used when building `\|\c -.B libg++\c -\&\|'.) -.TP -.B \-undef -Do not predefine any nonstandard macros. (Including architecture flags). -.TP -.B \-E -Run only the C preprocessor. Preprocess all the C source files -specified and output the results to standard output or to the -specified output file. -.TP -.B \-C -Tell the preprocessor not to discard comments. Used with the -`\|\c -.B \-E\c -\&\|' option. -.TP -.B \-P -Tell the preprocessor not to generate `\|\c -.B #line\c -\&\|' commands. -Used with the `\|\c -.B \-E\c -\&\|' option. -.TP -.B \-M\ [ \-MG ] -Tell the preprocessor to output a rule suitable for \c -.B make -describing the dependencies of each object file. For each source file, -the preprocessor outputs one \c -.B make\c -\&-rule whose target is the object -file name for that source file and whose dependencies are all the files -`\|\c -.B #include\c -\&\|'d in it. This rule may be a single line or may be -continued with `\|\c -.B \e\c -\&\|'-newline if it is long. The list of rules is -printed on standard output instead of the preprocessed C program. -.Sp -`\|\c -.B \-M\c -\&\|' implies `\|\c -.B \-E\c -\&\|'. -.Sp -`\|\c -.B \-MG\c -\&\|' says to treat missing header files as generated files and assume \c -they live in the same directory as the source file. It must be specified \c -in addition to `\|\c -.B \-M\c -\&\|'. -.TP -.B \-MM\ [ \-MG ] -Like `\|\c -.B \-M\c -\&\|' but the output mentions only the user header files -included with `\|\c -.B -#include "\c -.I file\c -.B -\&"\c -\&\|'. System header files -included with `\|\c -.B -#include <\c -.I file\c -.B -\&>\c -\&\|' are omitted. -.TP -.B \-MD -Like `\|\c -.B \-M\c -\&\|' but the dependency information is written to files with -names made by replacing `\|\c -.B .o\c -\&\|' with `\|\c -.B .d\c -\&\|' at the end of the -output file names. This is in addition to compiling the file as -specified\(em\&`\|\c -.B \-MD\c -\&\|' does not inhibit ordinary compilation the way -`\|\c -.B \-M\c -\&\|' does. -.Sp -The Mach utility `\|\c -.B md\c -\&\|' can be used to merge the `\|\c -.B .d\c -\&\|' files -into a single dependency file suitable for using with the `\|\c -.B make\c -\&\|' -command. -.TP -.B \-MMD -Like `\|\c -.B \-MD\c -\&\|' except mention only user header files, not system -header files. -.TP -.B \-H -Print the name of each header file used, in addition to other normal -activities. -.TP -.BI "\-A" "question" ( answer ) -Assert the answer -.I answer -for -.I question\c -\&, in case it is tested -with a preprocessor conditional such as `\|\c -.BI "#if #" question ( answer )\c -\&\|'. `\|\c -.B \-A\-\c -\&\|' disables the standard -assertions that normally describe the target machine. -.TP -.BI "\-A" "question"\c -\&(\c -.I answer\c -\&) -Assert the answer \c -.I answer\c -\& for \c -.I question\c -\&, in case it is tested -with a preprocessor conditional such as `\|\c -.B #if -#\c -.I question\c -\&(\c -.I answer\c -\&)\c -\&\|'. `\|\c -.B \-A-\c -\&\|' disables the standard -assertions that normally describe the target machine. -.TP -.BI \-D macro -Define macro \c -.I macro\c -\& with the string `\|\c -.B 1\c -\&\|' as its definition. -.TP -.BI \-D macro = defn -Define macro \c -.I macro\c -\& as \c -.I defn\c -\&. All instances of `\|\c -.B \-D\c -\&\|' on -the command line are processed before any `\|\c -.B \-U\c -\&\|' options. -.TP -.BI \-U macro -Undefine macro \c -.I macro\c -\&. `\|\c -.B \-U\c -\&\|' options are evaluated after all `\|\c -.B \-D\c -\&\|' options, but before any `\|\c -.B \-include\c -\&\|' and `\|\c -.B \-imacros\c -\&\|' options. -.TP -.B \-dM -Tell the preprocessor to output only a list of the macro definitions -that are in effect at the end of preprocessing. Used with the `\|\c -.B \-E\c -\&\|' -option. -.TP -.B \-dD -Tell the preprocessor to pass all macro definitions into the output, in -their proper sequence in the rest of the output. -.TP -.B \-dN -Like `\|\c -.B \-dD\c -\&\|' except that the macro arguments and contents are omitted. -Only `\|\c -.B #define \c -.I name\c -\&\c -\&\|' is included in the output. -.SH ASSEMBLER OPTION -.TP -.BI "\-Wa," "option" -Pass \c -.I option\c -\& as an option to the assembler. If \c -.I option -contains commas, it is split into multiple options at the commas. -.SH LINKER OPTIONS -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. -.TP -.I 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 GCC does a link step, these object files are used as input -to the linker. -.TP -.BI \-l library -Use the library named \c -.I library\c -\& when linking. -.Sp -The linker searches a standard list of directories for the library, -which is actually a file named `\|\c -.B lib\c -.I library\c -\&.a\c -\&\|'. The linker -then uses this file as if it had been specified precisely by name. -.Sp -The directories searched include several standard system directories -plus any that you specify with `\|\c -.B \-L\c -\&\|'. -.Sp -Normally the files found this way are library files\(em\&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. However, if the linker finds an -ordinary object file rather than a library, the object file is linked -in the usual fashion. The only difference between using an `\|\c -.B \-l\c -\&\|' option and specifying a file -name is that `\|\c -.B \-l\c -\&\|' surrounds -.I library -with `\|\c -.B lib\c -\&\|' and `\|\c -.B .a\c -\&\|' and searches several directories. -.TP -.B \-lobjc -You need this special case of the -.B \-l -option in order to link an Objective C program. -.TP -.B \-nostartfiles -Do not use the standard system startup files when linking. -The standard libraries are used normally. -.TP -.B \-nostdlib -Don't use the standard system libraries and startup files when linking. -Only the files you specify will be passed to the linker. -.TP -.B \-static -On systems that support dynamic linking, this prevents linking with the shared -libraries. On other systems, this option has no effect. -.TP -.B \-shared -Produce a shared object which can then be linked with other objects to -form an executable. Only a few systems support this option. -.TP -.B \-symbolic -Bind references to global symbols when building a shared object. Warn -about any unresolved references (unless overridden by the link editor -option `\|\c -.B -\-Xlinker \-z \-Xlinker defs\c -\&\|'). Only a few systems support -this option. -.TP -.BI "\-Xlinker " "option" -Pass \c -.I option -as an option to the linker. You can use this to -supply system-specific linker options which GNU CC does not know how to -recognize. -.Sp -If you want to pass an option that takes an argument, you must use -`\|\c -.B \-Xlinker\c -\&\|' twice, once for the option and once for the argument. -For example, to pass `\|\c -.B -\-assert definitions\c -\&\|', you must write -`\|\c -.B -\-Xlinker \-assert \-Xlinker definitions\c -\&\|'. It does not work to write -`\|\c -.B -\-Xlinker "\-assert definitions"\c -\&\|', because this passes the entire -string as a single argument, which is not what the linker expects. -.TP -.BI "\-Wl," "option" -Pass \c -.I option\c -\& as an option to the linker. If \c -.I option\c -\& contains -commas, it is split into multiple options at the commas. -.TP -.BI "\-u " "symbol" -Pretend the symbol -.I symbol -is undefined, to force linking of -library modules to define it. You can use `\|\c -.B \-u\c -\&\|' multiple times with -different symbols to force loading of additional library modules. -.SH DIRECTORY OPTIONS -These options specify directories to search for header files, for -libraries and for parts of the compiler: -.TP -.BI "\-I" "dir" -Append directory \c -.I dir\c -\& to the list of directories searched for include files. -.TP -.B \-I\- -Any directories you specify with `\|\c -.B \-I\c -\&\|' options before the `\|\c -.B \-I\-\c -\&\|' -option are searched only for the case of `\|\c -.B -#include "\c -.I file\c -.B -\&"\c -\&\|'; -they are not searched for `\|\c -.B -#include <\c -.I file\c -.B -\&>\c -\&\|'. -.Sp -If additional directories are specified with `\|\c -.B \-I\c -\&\|' options after -the `\|\c -.B \-I\-\c -\&\|', these directories are searched for all `\|\c -.B #include\c -\&\|' -directives. (Ordinarily \c -.I all\c -\& `\|\c -.B \-I\c -\&\|' directories are used -this way.) -.Sp -In addition, the `\|\c -.B \-I\-\c -\&\|' option inhibits the use of the current -directory (where the current input file came from) as the first search -directory for `\|\c -.B -#include "\c -.I file\c -.B -\&"\c -\&\|'. There is no way to -override this effect of `\|\c -.B \-I\-\c -\&\|'. With `\|\c -.B \-I.\c -\&\|' you can specify -searching the directory which was current when the compiler was -invoked. That is not exactly the same as what the preprocessor does -by default, but it is often satisfactory. -.Sp -`\|\c -.B \-I\-\c -\&\|' does not inhibit the use of the standard system directories -for header files. Thus, `\|\c -.B \-I\-\c -\&\|' and `\|\c -.B \-nostdinc\c -\&\|' are -independent. -.TP -.BI "\-L" "dir" -Add directory \c -.I dir\c -\& to the list of directories to be searched -for `\|\c -.B \-l\c -\&\|'. -.TP -.BI "\-B" "prefix" -This option specifies where to find the executables, libraries and -data files of the compiler itself. -.Sp -The compiler driver program runs one or more of the subprograms -`\|\c -.B cpp\c -\&\|', `\|\c -.B cc1\c -\&\|' (or, for C++, `\|\c -.B cc1plus\c -\&\|'), `\|\c -.B as\c -\&\|' and `\|\c -.B ld\c -\&\|'. It tries -.I prefix\c -\& as a prefix for each program it tries to run, both with and -without `\|\c -.I machine\c -.B /\c -.I version\c -.B /\c -\&\|'. -.Sp -For each subprogram to be run, the compiler driver first tries the -`\|\c -.B \-B\c -\&\|' prefix, if any. If that name is not found, or if `\|\c -.B \-B\c -\&\|' -was not specified, the driver tries two standard prefixes, which are -`\|\c -.B /usr/lib/gcc/\c -\&\|' and `\|\c -.B /usr/local/lib/gcc-lib/\c -\&\|'. If neither of -those results in a file name that is found, the compiler driver -searches for the unmodified program -name, using the directories specified in your -`\|\c -.B PATH\c -\&\|' environment variable. -.Sp -The run-time support file `\|\c -.B libgcc.a\c -\&\|' is also searched for using the -`\|\c -.B \-B\c -\&\|' prefix, if needed. If it is not found there, the two -standard prefixes above are tried, and that is all. The file is left -out of the link if it is not found by those means. Most of the time, -on most machines, `\|\c -.B libgcc.a\c -\&\|' is not actually necessary. -.Sp -You can get a similar result from the environment variable -.B GCC_EXEC_PREFIX\c -\&; if it is defined, its value is used as a prefix -in the same way. If both the `\|\c -.B \-B\c -\&\|' option and the -.B GCC_EXEC_PREFIX\c -\& variable are present, the `\|\c -.B \-B\c -\&\|' option is -used first and the environment variable value second. -.SH WARNING OPTIONS -Warnings are diagnostic messages that report constructions which -are not inherently erroneous but which are risky or suggest there -may have been an error. -.Sp -These options control the amount and kinds of warnings produced by GNU -CC: -.TP -.B \-fsyntax\-only -Check the code for syntax errors, but don't emit any output. -.TP -.B \-w -Inhibit all warning messages. -.TP -.B \-Wno\-import -Inhibit warning messages about the use of -.BR #import . -.TP -.B \-pedantic -Issue all the warnings demanded by strict ANSI standard C; reject -all programs that use forbidden extensions. -.Sp -Valid ANSI standard C programs should compile properly with or without -this option (though a rare few will require `\|\c -.B \-ansi\c -\&\|'). However, -without this option, certain GNU extensions and traditional C features -are supported as well. With this option, they are rejected. There is -no reason to \c -.I use\c -\& this option; it exists only to satisfy pedants. -.Sp -`\|\c -.B \-pedantic\c -\&\|' does not cause warning messages for use of the -alternate keywords whose names begin and end with `\|\c -.B _\|_\c -\&\|'. Pedantic -warnings are also disabled in the expression that follows -.B _\|_extension_\|_\c -\&. However, only system header files should use -these escape routes; application programs should avoid them. -.TP -.B \-pedantic\-errors -Like `\|\c -.B \-pedantic\c -\&\|', except that errors are produced rather than -warnings. -.TP -.B \-W -Print extra warning messages for these events: -.TP -\ \ \ \(bu -A nonvolatile automatic variable might be changed by a call to -.B longjmp\c -\&. These warnings are possible only in -optimizing compilation. -.Sp -The compiler sees only the calls to \c -.B setjmp\c -\&. It cannot know -where \c -.B longjmp\c -\& 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 \c -.B longjmp\c -\& cannot -in fact be called at the place which would cause a problem. -.TP -\ \ \ \(bu -A function can return either with or without a value. (Falling -off the end of the function body is considered returning without -a value.) For example, this function would evoke such a -warning: -.Sp -.nf -foo (a) -{ - if (a > 0) - return a; -} -.Sp -.fi -Spurious warnings can occur because GNU CC does not realize that -certain functions (including \c -.B abort\c -\& and \c -.B longjmp\c -\&) -will never return. -.TP -\ \ \ \(bu -An expression-statement or the left-hand side of a comma expression -contains no side effects. -To suppress the warning, cast the unused expression to void. -For example, an expression such as `\|\c -.B x[i,j]\c -\&\|' will cause a warning, -but `\|\c -.B x[(void)i,j]\c -\&\|' will not. -.TP -\ \ \ \(bu -An unsigned value is compared against zero with `\|\c -.B >\c -\&\|' or `\|\c -.B <=\c -\&\|'. -.PP -.TP -.B \-Wimplicit-int -Warn whenever a declaration does not specify a type. -.TP -.B \-Wimplicit-function-declaration -Warn whenever a function is used before being declared. -.TP -.B \-Wimplicit -Same as -Wimplicit-int and -Wimplicit-function-declaration. -.TP -.B \-Wmain -Warn if the -.B main -function is declared or defined with a suspicious type. -Typically, it is a function with external linkage, returning -.B int\c -\&, and -taking zero or two arguments. - -.TP -.B \-Wreturn\-type -Warn whenever a function is defined with a return-type that defaults -to \c -.B int\c -\&. Also warn about any \c -.B return\c -\& statement with no -return-value in a function whose return-type is not \c -.B void\c -\&. -.TP -.B \-Wunused -Warn whenever a local variable is unused aside from its declaration, -whenever a function is declared static but never defined, and whenever -a statement computes a result that is explicitly not used. -.TP -.B \-Wswitch -Warn whenever a \c -.B switch\c -\& statement has an index of enumeral type -and lacks a \c -.B case\c -\& for one or more of the named codes of that -enumeration. (The presence of a \c -.B default\c -\& label prevents this -warning.) \c -.B case\c -\& labels outside the enumeration range also -provoke warnings when this option is used. -.TP -.B \-Wcomment -Warn whenever a comment-start sequence `\|\c -.B /\(**\c -\&\|' appears in a comment. -.TP -.B \-Wtrigraphs -Warn if any trigraphs are encountered (assuming they are enabled). -.TP -.B \-Wformat -Check calls to \c -.B printf\c -\& and \c -.B scanf\c -\&, etc., to make sure that -the arguments supplied have types appropriate to the format string -specified. -.TP -.B \-Wchar\-subscripts -Warn if an array subscript has type -.BR char . -This is a common cause of error, as programmers often forget that this -type is signed on some machines. -.TP -.B \-Wuninitialized -An automatic variable is used without first being initialized. -.Sp -These warnings are possible only in optimizing compilation, -because they require data flow information that is computed only -when optimizing. If you don't specify `\|\c -.B \-O\c -\&\|', you simply won't -get these warnings. -.Sp -These warnings occur only for variables that are candidates for -register allocation. Therefore, they do not occur for a variable that -is declared \c -.B volatile\c -\&, or whose address is taken, or whose size -is other than 1, 2, 4 or 8 bytes. Also, they do not occur for -structures, unions or arrays, even when they are in registers. -.Sp -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. -.Sp -These warnings are made optional because GNU CC 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: -.Sp -.nf -{ - int x; - switch (y) - { - case 1: x = 1; - break; - case 2: x = 4; - break; - case 3: x = 5; - } - foo (x); -} -.Sp -.fi -If the value of \c -.B y\c -\& is always 1, 2 or 3, then \c -.B x\c -\& is -always initialized, but GNU CC doesn't know this. Here is -another common case: -.Sp -.nf -{ - int save_y; - if (change_y) save_y = y, y = new_y; - .\|.\|. - if (change_y) y = save_y; -} -.Sp -.fi -This has no bug because \c -.B save_y\c -\& is used only if it is set. -.Sp -Some spurious warnings can be avoided if you declare as -.B volatile\c -\& all the functions you use that never return. -.TP -.B \-Wparentheses -Warn if parentheses are omitted in certain contexts. -.TP -.B \-Wtemplate\-debugging -When using templates in a C++ program, warn if debugging is not yet -fully available (C++ only). -.TP -.B \-Wall -All of the above `\|\c -.B \-W\c -\&\|' options combined. These are all the -options which pertain to usage that we recommend avoiding and that we -believe is easy to avoid, even in conjunction with macros. -.PP -The remaining `\|\c -.B \-W.\|.\|.\c -\&\|' options are not implied by `\|\c -.B \-Wall\c -\&\|' -because they warn about constructions that we consider reasonable to -use, on occasion, in clean programs. -.TP -.B \-Wtraditional -Warn about certain constructs that behave differently in traditional and -ANSI C. -.TP -\ \ \ \(bu -Macro arguments occurring within string constants in the macro body. -These would substitute the argument in traditional C, but are part of -the constant in ANSI C. -.TP -\ \ \ \(bu -A function declared external in one block and then used after the end of -the block. -.TP -\ \ \ \(bu -A \c -.B switch\c -\& statement has an operand of type \c -.B long\c -\&. -.PP -.TP -.B \-Wshadow -Warn whenever a local variable shadows another local variable. -.TP -.BI "\-Wid\-clash\-" "len" -Warn whenever two distinct identifiers match in the first \c -.I len -characters. This may help you prepare a program that will compile -with certain obsolete, brain-damaged compilers. -.TP -.B \-Wpointer\-arith -Warn about anything that depends on the \*(lqsize of\*(rq a function type or -of \c -.B void\c -\&. GNU C assigns these types a size of 1, for -convenience in calculations with \c -.B void \(**\c -\& pointers and pointers -to functions. -.TP -.B \-Wcast\-qual -Warn whenever a pointer is cast so as to remove a type qualifier from -the target type. For example, warn if a \c -.B const char \(**\c -\& is cast -to an ordinary \c -.B char \(**\c -\&. -.TP -.B \-Wcast\-align -Warn whenever a pointer is cast such that the required alignment of the -target is increased. For example, warn if a \c -.B char \(**\c -\& is cast to -an \c -.B int \(**\c -\& on machines where integers can only be accessed at -two- or four-byte boundaries. -.TP -.B \-Wwrite\-strings -Give string constants the type \c -.B const char[\c -.I length\c -.B ]\c -\& so that -copying the address of one into a non-\c -.B const\c -\& \c -.B char \(** -pointer will get a warning. 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 \c -.B const\c -\& in -declarations and prototypes. Otherwise, it will just be a nuisance; -this is why we did not make `\|\c -.B \-Wall\c -\&\|' request these warnings. -.TP -.B \-Wconversion -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. -.TP -.B \-Waggregate\-return -Warn if any functions that return structures or unions are defined or -called. (In languages where you can return an array, this also elicits -a warning.) -.TP -.B \-Wstrict\-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.) -.TP -.B \-Wmissing\-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. -.TP -.B \-Wmissing\-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. -.TP -.B \-Wredundant-decls -Warn if anything is declared more than once in the same scope, even in -cases where multiple declaration is valid and changes nothing. -.TP -.B \-Wnested-externs -Warn if an \c -.B extern\c -\& declaration is encountered within a function. -.TP -.B \-Wenum\-clash -Warn about conversion between different enumeration types (C++ only). -.TP -.B \-Wlong-long -Warn if -.B long long \c -type is used. This is default. To inhibit -the warning messages, use flag `\|\c -.B \-Wno\-long\-long\c -\&\|'. Flags `\|\c -.B \-W\-long\-long\c -\&\|' and `\|\c -.B \-Wno\-long\-long\c -\&\|' are taken into account only when flag `\|\c -.B \-pedantic\c -\&\|' is used. -.TP -.B \-Woverloaded\-virtual -(C++ only.) -In a derived class, the definitions of virtual functions must match -the type signature of a virtual function declared in the base class. -Use this option to request warnings when a derived class declares a -function that may be an erroneous attempt to define a virtual -function: that is, warn when a function with the same name as a -virtual function in the base class, but with a type signature that -doesn't match any virtual functions from the base class. -.TP -.B \-Winline -Warn if a function can not be inlined, and either it was declared as inline, -or else the -.B \-finline\-functions -option was given. -.TP -.B \-Werror -Treat warnings as errors; abort compilation after any warning. -.SH DEBUGGING OPTIONS -GNU CC has various special options that are used for debugging -either your program or GCC: -.TP -.B \-g -Produce debugging information in the operating system's native format -(stabs, COFF, XCOFF, or DWARF). GDB can work with this debugging -information. -.Sp -On most systems that use stabs format, `\|\c -.B \-g\c -\&\|' enables use of extra -debugging information that only GDB can use; this extra information -makes debugging work better in GDB but will probably make other debuggers -crash or -refuse to read the program. If you want to control for certain whether -to generate the extra information, use `\|\c -.B \-gstabs+\c -\&\|', `\|\c -.B \-gstabs\c -\&\|', -`\|\c -.B \-gxcoff+\c -\&\|', `\|\c -.B \-gxcoff\c -\&\|', `\|\c -.B \-gdwarf+\c -\&\|', or `\|\c -.B \-gdwarf\c -\&\|' -(see below). -.Sp -Unlike most other C compilers, GNU CC allows you to use `\|\c -.B \-g\c -\&\|' with -`\|\c -.B \-O\c -\&\|'. 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 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. -.Sp -Nevertheless it proves possible to debug optimized output. This makes -it reasonable to use the optimizer for programs that might have bugs. -.PP -The following options are useful when GNU CC is generated with the -capability for more than one debugging format. -.TP -.B \-ggdb -Produce debugging information in the native format (if that is supported), -including GDB extensions if at all possible. -.TP -.B \-gstabs -Produce debugging information in stabs format (if that is supported), -without GDB extensions. This is the format used by DBX on most BSD -systems. -.TP -.B \-gstabs+ -Produce debugging information in stabs format (if that is supported), -using GNU extensions understood only by the GNU debugger (GDB). The -use of these extensions is likely to make other debuggers crash or -refuse to read the program. -.TP -.B \-gcoff -Produce debugging information in COFF format (if that is supported). -This is the format used by SDB on most System V systems prior to -System V Release 4. -.TP -.B \-gxcoff -Produce debugging information in XCOFF format (if that is supported). -This is the format used by the DBX debugger on IBM RS/6000 systems. -.TP -.B \-gxcoff+ -Produce debugging information in XCOFF format (if that is supported), -using GNU extensions understood only by the GNU debugger (GDB). The -use of these extensions is likely to make other debuggers crash or -refuse to read the program. -.TP -.B \-gdwarf -Produce debugging information in DWARF format (if that is supported). -This is the format used by SDB on most System V Release 4 systems. -.TP -.B \-gdwarf+ -Produce debugging information in DWARF format (if that is supported), -using GNU extensions understood only by the GNU debugger (GDB). The -use of these extensions is likely to make other debuggers crash or -refuse to read the program. -.PP -.BI "\-g" "level" -.br -.BI "\-ggdb" "level" -.br -.BI "\-gstabs" "level" -.br -.BI "\-gcoff" "level" -.BI "\-gxcoff" "level" -.TP -.BI "\-gdwarf" "level" -Request debugging information and also use \c -.I level\c -\& to specify how -much information. The default level is 2. -.Sp -Level 1 produces minimal information, 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. -.Sp -Level 3 includes extra information, such as all the macro definitions -present in the program. Some debuggers support macro expansion when -you use `\|\c -.B \-g3\c -\&\|'. -.TP -.B \-p -Generate extra code to write profile information suitable for the -analysis program \c -.B prof\c -\&. -.TP -.B \-pg -Generate extra code to write profile information suitable for the -analysis program \c -.B gprof\c -\&. -.TP -.B \-a -Generate extra code to write profile information for basic blocks, -which will record the number of times each basic block is executed. -This data could be analyzed by a program like \c -.B tcov\c -\&. Note, -however, that the format of the data is not what \c -.B tcov\c -\& expects. -Eventually GNU \c -.B gprof\c -\& should be extended to process this data. -.TP -.B \-ax -Generate extra code to read basic block profiling parameters from -file `bb.in' and write profiling results to file `bb.out'. -`bb.in' contains a list of functions. Whenever a function on the list -is entered, profiling is turned on. When the outmost function is left, -profiling is turned off. If a function name is prefixed with `-' -the function is excluded from profiling. If a function name is not -unique it can be disambiguated by writing -`/path/filename.d:functionname'. `bb.out' will list some available -filenames. -Four function names have a special meaning: -`__bb_jumps__' will cause jump frequencies to be written to `bb.out'. -`__bb_trace__' will cause the sequence of basic blocks to be piped -into `gzip' and written to file `bbtrace.gz'. -`__bb_hidecall__' will cause call instructions to be excluded from -the trace. -`__bb_showret__' will cause return instructions to be included in -the trace. -.TP -.BI "\-d" "letters" -Says to make debugging dumps during compilation at times specified by -.I letters\c -\&. This is used for debugging the compiler. The file names -for most of the dumps are made by appending a word to the source file -name (e.g. `\|\c -.B foo.c.rtl\c -\&\|' or `\|\c -.B foo.c.jump\c -\&\|'). -.TP -.B \-dM -Dump all macro definitions, at the end of preprocessing, and write no -output. -.TP -.B \-dN -Dump all macro names, at the end of preprocessing. -.TP -.B \-dD -Dump all macro definitions, at the end of preprocessing, in addition to -normal output. -.TP -.B \-dy -Dump debugging information during parsing, to standard error. -.TP -.B \-dr -Dump after RTL generation, to `\|\c -.I file\c -.B \&.rtl\c -\&\|'. -.TP -.B \-dx -Just generate RTL for a function instead of compiling it. Usually used -with `\|\c -.B r\c -\&\|'. -.TP -.B \-dj -Dump after first jump optimization, to `\|\c -.I file\c -.B \&.jump\c -\&\|'. -.TP -.B \-ds -Dump after CSE (including the jump optimization that sometimes -follows CSE), to `\|\c -.I file\c -.B \&.cse\c -\&\|'. -.TP -.B \-dL -Dump after loop optimization, to `\|\c -.I file\c -.B \&.loop\c -\&\|'. -.TP -.B \-dt -Dump after the second CSE pass (including the jump optimization that -sometimes follows CSE), to `\|\c -.I file\c -.B \&.cse2\c -\&\|'. -.TP -.B \-df -Dump after flow analysis, to `\|\c -.I file\c -.B \&.flow\c -\&\|'. -.TP -.B \-dc -Dump after instruction combination, to `\|\c -.I file\c -.B \&.combine\c -\&\|'. -.TP -.B \-dS -Dump after the first instruction scheduling pass, to -`\|\c -.I file\c -.B \&.sched\c -\&\|'. -.TP -.B \-dl -Dump after local register allocation, to `\|\c -.I file\c -.B \&.lreg\c -\&\|'. -.TP -.B \-dg -Dump after global register allocation, to `\|\c -.I file\c -.B \&.greg\c -\&\|'. -.TP -.B \-dR -Dump after the second instruction scheduling pass, to -`\|\c -.I file\c -.B \&.sched2\c -\&\|'. -.TP -.B \-dJ -Dump after last jump optimization, to `\|\c -.I file\c -.B \&.jump2\c -\&\|'. -.TP -.B \-dd -Dump after delayed branch scheduling, to `\|\c -.I file\c -.B \&.dbr\c -\&\|'. -.TP -.B \-dk -Dump after conversion from registers to stack, to `\|\c -.I file\c -.B \&.stack\c -\&\|'. -.TP -.B \-da -Produce all the dumps listed above. -.TP -.B \-dm -Print statistics on memory usage, at the end of the run, to -standard error. -.TP -.B \-dp -Annotate the assembler output with a comment indicating which -pattern and alternative was used. -.TP -.B \-fpretend\-float -When running a cross-compiler, pretend that the target machine uses the -same floating point format as the host machine. This causes incorrect -output of the actual floating constants, but the actual instruction -sequence will probably be the same as GNU CC would make when running on -the target machine. -.TP -.B \-save\-temps -Store the usual \*(lqtemporary\*(rq intermediate files permanently; place them -in the current directory and name them based on the source file. Thus, -compiling `\|\c -.B foo.c\c -\&\|' with `\|\c -.B \-c \-save\-temps\c -\&\|' would produce files -`\|\c -.B foo.cpp\c -\&\|' and `\|\c -.B foo.s\c -\&\|', as well as `\|\c -.B foo.o\c -\&\|'. -.TP -.BI "\-print\-file\-name=" "library" -Print the full absolute name of the library file \|\c -.nh -.I library -.hy -\&\| that -would be used when linking\(em\&and do not do anything else. With this -option, GNU CC does not compile or link anything; it just prints the -file name. -.TP -.B \-print\-libgcc\-file\-name -Same as `\|\c -.B \-print\-file\-name=libgcc.a\c -\&\|'. -.TP -.BI "\-print\-prog\-name=" "program" -Like `\|\c -.B \-print\-file\-name\c -\&\|', but searches for a program such as `\|\c -cpp\c -\&\|'. -.SH OPTIMIZATION OPTIONS -These options control various sorts of optimizations: -.TP -.B \-O -.TP -.B \-O1 -Optimize. Optimizing compilation takes somewhat more time, and a lot -more memory for a large function. -.Sp -Without `\|\c -.B \-O\c -\&\|', the compiler's goal is to reduce the cost of -compilation and to make debugging 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. -.Sp -Without `\|\c -.B \-O\c -\&\|', only variables declared \c -.B register\c -\& are -allocated in registers. The resulting compiled code is a little worse -than produced by PCC without `\|\c -.B \-O\c -\&\|'. -.Sp -With `\|\c -.B \-O\c -\&\|', the compiler tries to reduce code size and execution -time. -.Sp -When you specify `\|\c -.B \-O\c -\&\|', the two options `\|\c -.B \-fthread\-jumps\c -\&\|' and `\|\c -.B \-fdefer\-pop\c -\&\|' are turned on. On machines that have delay slots, the `\|\c -.B \-fdelayed\-branch\c -\&\|' option is turned on. For those machines that can support debugging even -without a frame pointer, the `\|\c -.B \-fomit\-frame\-pointer\c -\&\|' option is turned on. On some machines other flags may also be turned on. -.TP -.B \-O2 -Optimize even more. Nearly all supported optimizations that do not -involve a space-speed tradeoff are performed. Loop unrolling and function -inlining are not done, for example. As compared to -.B \-O\c -\&, -this option increases both compilation time and the performance of the -generated code. -.TP -.B \-O3 -Optimize yet more. This turns on everything -.B \-O2 -does, along with also turning on -.B \-finline\-functions. -.TP -.B \-Os -Optimize for size. -This enables all -.B \-O2 -optimizations that do not typically increase code size. -It also performs further optimizations designed to reduce code size. -.TP -.B \-O0 -Do not optimize. -.Sp -If you use multiple -.B \-O -options, with or without level numbers, the last such option is the -one that is effective. -.PP -Options of the form `\|\c -.B \-f\c -.I flag\c -\&\c -\&\|' specify machine-independent -flags. Most flags have both positive and negative forms; the negative -form of `\|\c -.B \-ffoo\c -\&\|' would be `\|\c -.B \-fno\-foo\c -\&\|'. The following list shows -only one form\(em\&the one which is not the default. -You can figure out the other form by either removing `\|\c -.B no\-\c -\&\|' or -adding it. -.TP -.B \-ffloat\-store -Do not store floating point variables in registers. This -prevents undesirable excess precision on machines such as the -68000 where the floating registers (of the 68881) keep more -precision than a \c -.B double\c -\& is supposed to have. -.Sp -For most programs, the excess precision does only good, but a few -programs rely on the precise definition of IEEE floating point. -Use `\|\c -.B \-ffloat\-store\c -\&\|' for such programs. -.TP -.B \-fmemoize\-lookups -.TP -.B \-fsave\-memoized -Use heuristics to compile faster (C++ only). These heuristics are not -enabled by default, since they are only effective for certain input -files. Other input files compile more slowly. -.Sp -The first time the compiler must build a call to a member function (or -reference to a data member), it must (1) determine whether the class -implements member functions of that name; (2) resolve which member -function to call (which involves figuring out what sorts of type -conversions need to be made); and (3) check the visibility of the member -function to the caller. All of this adds up to slower compilation. -Normally, the second time a call is made to that member function (or -reference to that data member), it must go through the same lengthy -process again. This means that code like this -.Sp -\& cout << "This " << p << " has " << n << " legs.\en"; -.Sp -makes six passes through all three steps. By using a software cache, -a \*(lqhit\*(rq significantly reduces this cost. Unfortunately, using the -cache introduces another layer of mechanisms which must be implemented, -and so incurs its own overhead. `\|\c -.B \-fmemoize\-lookups\c -\&\|' enables -the software cache. -.Sp -Because access privileges (visibility) to members and member functions -may differ from one function context to the next, -.B g++ -may need to flush the cache. With the `\|\c -.B \-fmemoize\-lookups\c -\&\|' flag, the cache is flushed after every -function that is compiled. The `\|\c -\-fsave\-memoized\c -\&\|' flag enables the same software cache, but when the compiler -determines that the context of the last function compiled would yield -the same access privileges of the next function to compile, it -preserves the cache. -This is most helpful when defining many member functions for the same -class: with the exception of member functions which are friends of -other classes, each member function has exactly the same access -privileges as every other, and the cache need not be flushed. -.TP -.B \-fno\-default\-inline -Don't make member functions inline by default merely because they are -defined inside the class scope (C++ only). -.TP -.B \-fno\-defer\-pop -Always pop the arguments to each function call as soon as that -function returns. For machines which must pop arguments after a -function call, the compiler normally lets arguments accumulate on the -stack for several function calls and pops them all at once. -.TP -.B \-fforce\-mem -Force memory operands to be copied into registers before doing -arithmetic on them. This may produce better code by making all -memory references potential common subexpressions. When they are -not common subexpressions, instruction combination should -eliminate the separate register-load. I am interested in hearing -about the difference this makes. -.TP -.B \-fforce\-addr -Force memory address constants to be copied into registers before -doing arithmetic on them. This may produce better code just as -`\|\c -.B \-fforce\-mem\c -\&\|' may. I am interested in hearing about the -difference this makes. -.TP -.B \-fomit\-frame\-pointer -Don't keep the frame pointer in a register for functions that -don't need one. This avoids the instructions to save, set up and -restore frame pointers; it also makes an extra register available -in many functions. \c -.I It also makes debugging impossible on most machines\c -\&. -.Sp -On some machines, such as the Vax, this flag has no effect, because -the standard calling sequence automatically handles the frame pointer -and nothing is saved by pretending it doesn't exist. The -machine-description macro \c -.B FRAME_POINTER_REQUIRED\c -\& controls -whether a target machine supports this flag. -.TP -.B \-finline\-functions -Integrate all simple functions into their callers. The compiler -heuristically decides which functions are simple enough to be worth -integrating in this way. -.Sp -If all calls to a given function are integrated, and the function is -declared \c -.B static\c -\&, then GCC normally does not output the function as -assembler code in its own right. -.TP -.B \-fcaller\-saves -Enable values to be allocated in registers that will be clobbered by -function calls, by emitting extra instructions to save and restore the -registers around such calls. Such allocation is done only when it -seems to result in better code than would otherwise be produced. -.Sp -This option is enabled by default on certain machines, usually those -which have no call-preserved registers to use instead. -.TP -.B \-fkeep\-inline\-functions -Even if all calls to a given function are integrated, and the function -is declared \c -.B static\c -\&, nevertheless output a separate run-time -callable version of the function. -.TP -.B \-fno\-function\-cse -Do not put function addresses in registers; make each instruction that -calls a constant function contain the function's address explicitly. -.Sp -This option results in less efficient code, but some strange hacks -that alter the assembler output may be confused by the optimizations -performed when this option is not used. -.TP -.B \-fno\-peephole -Disable any machine-specific peephole optimizations. -.TP -.B \-ffast-math -This option allows GCC to violate some ANSI or IEEE rules/specifications -in the interest of optimizing code for speed. For example, it allows -the compiler to assume arguments to the \c -.B sqrt\c -\& function are -non-negative numbers. -.Sp -This option should never be turned on by any `\|\c -.B \-O\c -\&\|' option since -it can result in incorrect output for programs which depend on -an exact implementation of IEEE or ANSI rules/specifications for -math functions. -.PP -The following options control specific optimizations. The `\|\c -.B \-O2\c -\&\|' -option turns on all of these optimizations except `\|\c -.B \-funroll\-loops\c -\&\|' -and `\|\c -.B \-funroll\-all\-loops\c -\&\|'. -.PP -The `\|\c -.B \-O\c -\&\|' option usually turns on -the `\|\c -.B \-fthread\-jumps\c -\&\|' and `\|\c -.B \-fdelayed\-branch\c -\&\|' options, but -specific machines may change the default optimizations. -.PP -You can use the following flags in the rare cases when \*(lqfine-tuning\*(rq -of optimizations to be performed is desired. -.TP -.B \-fstrength\-reduce -Perform the optimizations of loop strength reduction and -elimination of iteration variables. -.TP -.B \-fthread\-jumps -Perform optimizations where we check to see if a jump branches to a -location where another comparison subsumed by the first is found. If -so, the first branch is redirected to either the destination of the -second branch or a point immediately following it, depending on whether -the condition is known to be true or false. -.TP -.B \-funroll\-loops -Perform the optimization of loop unrolling. This is only done for loops -whose number of iterations can be determined at compile time or run time. -.TP -.B \-funroll\-all\-loops -Perform the optimization of loop unrolling. This is done for all loops. -This usually makes programs run more slowly. -.TP -.B \-fcse\-follow\-jumps -In common subexpression elimination, scan through jump instructions -when the target of the jump is not reached by any other path. For -example, when CSE encounters an \c -.B if\c -\& statement with an -.B else\c -\& clause, CSE will follow the jump when the condition -tested is false. -.TP -.B \-fcse\-skip\-blocks -This is similar to `\|\c -.B \-fcse\-follow\-jumps\c -\&\|', but causes CSE to -follow jumps which conditionally skip over blocks. When CSE -encounters a simple \c -.B if\c -\& statement with no else clause, -`\|\c -.B \-fcse\-skip\-blocks\c -\&\|' causes CSE to follow the jump around the -body of the \c -.B if\c -\&. -.TP -.B \-frerun\-cse\-after\-loop -Re-run common subexpression elimination after loop optimizations has been -performed. -.TP -.B \-felide\-constructors -Elide constructors when this seems plausible (C++ only). With this -flag, GNU C++ initializes \c -.B y\c -\& directly from the call to \c -.B foo -without going through a temporary in the following code: -.Sp -A foo (); -A y = foo (); -.Sp -Without this option, GNU C++ first initializes \c -.B y\c -\& by calling the -appropriate constructor for type \c -.B A\c -\&; then assigns the result of -.B foo\c -\& to a temporary; and, finally, replaces the initial value of -`\|\c -.B y\c -\&\|' with the temporary. -.Sp -The default behavior (`\|\c -.B \-fno\-elide\-constructors\c -\&\|') is specified by -the draft ANSI C++ standard. If your program's constructors have side -effects, using `\|\c -.B \-felide-constructors\c -\&\|' can make your program act -differently, since some constructor calls may be omitted. -.TP -.B \-fexpensive\-optimizations -Perform a number of minor optimizations that are relatively expensive. -.TP -.B \-fdelayed\-branch -If supported for the target machine, attempt to reorder instructions -to exploit instruction slots available after delayed branch -instructions. -.TP -.B \-fschedule\-insns -If supported for the target machine, attempt to reorder instructions to -eliminate execution stalls due to required data being unavailable. This -helps machines that have slow floating point or memory load instructions -by allowing other instructions to be issued until the result of the load -or floating point instruction is required. -.TP -.B \-fschedule\-insns2 -Similar to `\|\c -.B \-fschedule\-insns\c -\&\|', but requests an additional pass of -instruction scheduling after register allocation has been done. This is -especially useful on machines with a relatively small number of -registers and where memory load instructions take more than one cycle. -.SH TARGET OPTIONS -By default, GNU CC compiles code for the same type of machine that you -are using. However, it can also be installed as a cross-compiler, to -compile for some other type of machine. In fact, several different -configurations of GNU CC, for different target machines, can be -installed side by side. Then you specify which one to use with the -`\|\c -.B \-b\c -\&\|' option. -.PP -In addition, older and newer versions of GNU CC can be installed side -by side. One of them (probably the newest) will be the default, but -you may sometimes wish to use another. -.TP -.BI "\-b " "machine" -The argument \c -.I machine\c -\& specifies the target machine for compilation. -This is useful when you have installed GNU CC as a cross-compiler. -.Sp -The value to use for \c -.I machine\c -\& is the same as was specified as the -machine type when configuring GNU CC as a cross-compiler. For -example, if a cross-compiler was configured with `\|\c -.B configure -i386v\c -\&\|', meaning to compile for an 80386 running System V, then you -would specify `\|\c -.B \-b i386v\c -\&\|' to run that cross compiler. -.Sp -When you do not specify `\|\c -.B \-b\c -\&\|', it normally means to compile for -the same type of machine that you are using. -.TP -.BI "\-V " "version" -The argument \c -.I version\c -\& specifies which version of GNU CC to run. -This is useful when multiple versions are installed. For example, -.I version\c -\& might be `\|\c -.B 2.0\c -\&\|', meaning to run GNU CC version 2.0. -.Sp -The default version, when you do not specify `\|\c -.B \-V\c -\&\|', is controlled -by the way GNU CC is installed. Normally, it will be a version that -is recommended for general use. -.SH MACHINE DEPENDENT OPTIONS -Each of the target machine types can have its own special options, -starting with `\|\c -.B \-m\c -\&\|', to choose among various hardware models or -configurations\(em\&for example, 68010 vs 68020, floating coprocessor or -none. A single installed version of the compiler can compile for any -model or configuration, according to the options specified. -.PP -Some configurations of the compiler also support additional special -options, usually for command-line compatibility with other compilers on -the same platform. -.PP -These are the `\|\c -.B \-m\c -\&\|' options defined for the 68000 series: -.TP -.B \-m68000 -.TP -.B \-mc68000 -Generate output for a 68000. This is the default when the compiler is -configured for 68000-based systems. -.TP -.B \-m68020 -.TP -.B \-mc68020 -Generate output for a 68020 (rather than a 68000). This is the -default when the compiler is configured for 68020-based systems. -.TP -.B \-m68881 -Generate output containing 68881 instructions for floating point. -This is the default for most 68020-based systems unless -.B \-nfp -was specified when the compiler was configured. -.TP -.B \-m68030 -Generate output for a 68030. This is the default when the compiler is -configured for 68030-based systems. -.TP -.B \-m68040 -Generate output for a 68040. This is the default when the compiler is -configured for 68040-based systems. -.TP -.B \-m68020\-40 -Generate output for a 68040, without using any of the new instructions. -This results in code which can run relatively efficiently on either a -68020/68881 or a 68030 or a 68040. -.TP -.B \-mfpa -Generate output containing Sun FPA instructions for floating point. -.TP -.B \-msoft\-float -Generate output containing library calls for floating point. -.I -WARNING: -the requisite libraries are not part of GNU CC. Normally the -facilities of the machine's usual C compiler are used, but this can't -be done directly in cross-compilation. You must make your own -arrangements to provide suitable library functions for cross-compilation. -.TP -.B \-mshort -Consider type \c -.B int\c -\& to be 16 bits wide, like \c -.B short int\c -\&. -.TP -.B \-mnobitfield -Do not use the bit-field instructions. `\|\c -.B \-m68000\c -\&\|' implies -`\|\c -.B \-mnobitfield\c -\&\|'. -.TP -.B \-mbitfield -Do use the bit-field instructions. `\|\c -.B \-m68020\c -\&\|' implies -`\|\c -.B \-mbitfield\c -\&\|'. This is the default if you use the unmodified -sources. -.TP -.B \-mrtd -Use a different function-calling convention, in which functions -that take a fixed number of arguments return with the \c -.B rtd -instruction, which pops their arguments while returning. This -saves one instruction in the caller since there is no need to pop -the arguments there. -.Sp -This calling convention is incompatible with the one normally -used on Unix, so you cannot use it if you need to call libraries -compiled with the Unix compiler. -.Sp -Also, you must provide function prototypes for all functions that -take variable numbers of arguments (including \c -.B printf\c -\&); -otherwise incorrect code will be generated for calls to those -functions. -.Sp -In addition, seriously incorrect code will result if you call a -function with too many arguments. (Normally, extra arguments are -harmlessly ignored.) -.Sp -The \c -.B rtd\c -\& instruction is supported by the 68010 and 68020 -processors, but not by the 68000. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the Vax: -.TP -.B \-munix -Do not output certain jump instructions (\c -.B aobleq\c -\& and so on) -that the Unix assembler for the Vax cannot handle across long -ranges. -.TP -.B \-mgnu -Do output those jump instructions, on the assumption that you -will assemble with the GNU assembler. -.TP -.B \-mg -Output code for g-format floating point numbers instead of d-format. -.PP -These `\|\c -.B \-m\c -\&\|' switches are supported on the SPARC: -.PP -.B \-mfpu -.TP -.B \-mhard\-float -Generate output containing floating point instructions. This is the -default. -.PP -.B \-mno\-fpu -.TP -.B \-msoft\-float -Generate output containing library calls for floating point. -.I Warning: -there is no GNU floating-point library for SPARC. -Normally the facilities of the machine's usual C compiler are used, but -this cannot be done directly in cross-compilation. You must make your -own arrangements to provide suitable library functions for -cross-compilation. -.Sp -.B \-msoft\-float -changes the calling convention in the output file; -therefore, it is only useful if you compile -.I all -of a program with this option. -.PP -.B \-mno\-epilogue -.TP -.B \-mepilogue -With -.B \-mepilogue -(the default), the compiler always emits code for -function exit at the end of each function. Any function exit in -the middle of the function (such as a return statement in C) will -generate a jump to the exit code at the end of the function. -.Sp -With -.BR \-mno\-epilogue , -the compiler tries to emit exit code inline at every function exit. -.PP -.B \-mno\-v8 -.TP -.B \-mv8 -.TP -.B \-msparclite -These three options select variations on the SPARC architecture. -.Sp -By default (unless specifically configured for the Fujitsu SPARClite), -GCC generates code for the v7 variant of the SPARC architecture. -.Sp -.B \-mv8 -will give you SPARC v8 code. The only difference from v7 -code is that the compiler emits the integer multiply and integer -divide instructions which exist in SPARC v8 but not in SPARC v7. -.Sp -.B \-msparclite -will give you SPARClite code. This adds the integer -multiply, integer divide step and scan (ffs) instructions which -exist in SPARClite but not in SPARC v7. -.PP -.B \-mcypress -.TP -.B \-msupersparc -These two options select the processor for which the code is optimized. -.Sp -With -.B \-mcypress -(the default), the compiler optimizes code for the Cypress CY7C602 chip, as -used in the SparcStation/SparcServer 3xx series. This is also appropriate for -the older SparcStation 1, 2, IPX etc. -.Sp -With -.B \-msupersparc -the compiler optimizes code for the SuperSparc cpu, as used in the SparcStation -10, 1000 and 2000 series. This flag also enables use of the full SPARC v8 -instruction set. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the Convex: -.TP -.B \-mc1 -Generate output for a C1. This is the default when the compiler is -configured for a C1. -.TP -.B \-mc2 -Generate output for a C2. This is the default when the compiler is -configured for a C2. -.TP -.B \-margcount -Generate code which puts an argument count in the word preceding each -argument list. Some nonportable Convex and Vax programs need this word. -(Debuggers don't, except for functions with variable-length argument -lists; this info is in the symbol table.) -.TP -.B \-mnoargcount -Omit the argument count word. This is the default if you use the -unmodified sources. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the AMD Am29000: -.TP -.B \-mdw -Generate code that assumes the DW bit is set, i.e., that byte and -halfword operations are directly supported by the hardware. This is the -default. -.TP -.B \-mnodw -Generate code that assumes the DW bit is not set. -.TP -.B \-mbw -Generate code that assumes the system supports byte and halfword write -operations. This is the default. -.TP -.B \-mnbw -Generate code that assumes the systems does not support byte and -halfword write operations. This implies `\|\c -.B \-mnodw\c -\&\|'. -.TP -.B \-msmall -Use a small memory model that assumes that all function addresses are -either within a single 256 KB segment or at an absolute address of less -than 256K. This allows the \c -.B call\c -\& instruction to be used instead -of a \c -.B const\c -\&, \c -.B consth\c -\&, \c -.B calli\c -\& sequence. -.TP -.B \-mlarge -Do not assume that the \c -.B call\c -\& instruction can be used; this is the -default. -.TP -.B \-m29050 -Generate code for the Am29050. -.TP -.B \-m29000 -Generate code for the Am29000. This is the default. -.TP -.B \-mkernel\-registers -Generate references to registers \c -.B gr64-gr95\c -\& instead of -.B gr96-gr127\c -\&. This option can be used when compiling kernel code -that wants a set of global registers disjoint from that used by -user-mode code. -.Sp -Note that when this option is used, register names in `\|\c -.B \-f\c -\&\|' flags -must use the normal, user-mode, names. -.TP -.B \-muser\-registers -Use the normal set of global registers, \c -.B gr96-gr127\c -\&. This is the -default. -.TP -.B \-mstack\-check -Insert a call to \c -.B _\|_msp_check\c -\& after each stack adjustment. This -is often used for kernel code. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for Motorola 88K architectures: -.TP -.B \-m88000 -Generate code that works well on both the m88100 and the -m88110. -.TP -.B \-m88100 -Generate code that works best for the m88100, but that also -runs on the m88110. -.TP -.B \-m88110 -Generate code that works best for the m88110, and may not run -on the m88100. -.TP -.B \-midentify\-revision -Include an \c -.B ident\c -\& directive in the assembler output recording the -source file name, compiler name and version, timestamp, and compilation -flags used. -.TP -.B \-mno\-underscores -In assembler output, emit symbol names without adding an underscore -character at the beginning of each name. The default is to use an -underscore as prefix on each name. -.TP -.B \-mno\-check\-zero\-division -.TP -.B \-mcheck\-zero\-division -Early models of the 88K architecture had problems with division by zero; -in particular, many of them didn't trap. Use these options to avoid -including (or to include explicitly) additional code to detect division -by zero and signal an exception. All GCC configurations for the 88K use -`\|\c -.B \-mcheck\-zero\-division\c -\&\|' by default. -.TP -.B \-mocs\-debug\-info -.TP -.B \-mno\-ocs\-debug\-info -Include (or omit) additional debugging information (about -registers used in each stack frame) as specified in the 88Open Object -Compatibility Standard, \*(lqOCS\*(rq. This extra information is not needed -by GDB. The default for DG/UX, SVr4, and Delta 88 SVr3.2 is to -include this information; other 88k configurations omit this information -by default. -.TP -.B \-mocs\-frame\-position -.TP -.B \-mno\-ocs\-frame\-position -Force (or do not require) register values to be stored in a particular -place in stack frames, as specified in OCS. The DG/UX, Delta88 SVr3.2, -and BCS configurations use `\|\c -.B \-mocs\-frame\-position\c -\&\|'; other 88k -configurations have the default `\|\c -.B \-mno\-ocs\-frame\-position\c -\&\|'. -.TP -.B \-moptimize\-arg\-area -.TP -.B \-mno\-optimize\-arg\-area -Control how to store function arguments in stack frames. -`\|\c -.B \-moptimize\-arg\-area\c -\&\|' saves space, but may break some -debuggers (not GDB). `\|\c -.B \-mno\-optimize\-arg\-area\c -\&\|' conforms better to -standards. By default GCC does not optimize the argument area. -.TP -.BI "\-mshort\-data\-" "num" -.I num -Generate smaller data references by making them relative to \c -.B r0\c -\&, -which allows loading a value using a single instruction (rather than the -usual two). You control which data references are affected by -specifying \c -.I num\c -\& with this option. For example, if you specify -`\|\c -.B \-mshort\-data\-512\c -\&\|', then the data references affected are those -involving displacements of less than 512 bytes. -`\|\c -.B \-mshort\-data\-\c -.I num\c -\&\c -\&\|' is not effective for \c -.I num\c -\& greater -than 64K. -.PP -.B \-mserialize-volatile -.TP -.B \-mno-serialize-volatile -Do, or do not, generate code to guarantee sequential consistency of -volatile memory references. -.Sp -GNU CC always guarantees consistency by default, for the preferred -processor submodel. How this is done depends on the submodel. -.Sp -The m88100 processor does not reorder memory references and so always -provides sequential consistency. If you use `\|\c -.B \-m88100\c -\&\|', GNU CC does -not generate any special instructions for sequential consistency. -.Sp -The order of memory references made by the m88110 processor does not -always match the order of the instructions requesting those references. -In particular, a load instruction may execute before a preceding store -instruction. Such reordering violates sequential consistency of -volatile memory references, when there are multiple processors. When -you use `\|\c -.B \-m88000\c -\&\|' or `\|\c -.B \-m88110\c -\&\|', GNU CC generates special -instructions when appropriate, to force execution in the proper order. -.Sp -The extra code generated to guarantee consistency may affect the -performance of your application. If you know that you can safely forgo -this guarantee, you may use the option `\|\c -.B \-mno-serialize-volatile\c -\&\|'. -.Sp -If you use the `\|\c -.B \-m88100\c -\&\|' option but require sequential consistency -when running on the m88110 processor, you should use -`\|\c -.B \-mserialize-volatile\c -\&\|'. -.PP -.B \-msvr4 -.TP -.B \-msvr3 -Turn on (`\|\c -.B \-msvr4\c -\&\|') or off (`\|\c -.B \-msvr3\c -\&\|') compiler extensions -related to System V release 4 (SVr4). This controls the following: -.TP -\ \ \ \(bu -Which variant of the assembler syntax to emit (which you can select -independently using `\|\c -.B \-mversion\-03.00\c -\&\|'). -.TP -\ \ \ \(bu -`\|\c -.B \-msvr4\c -\&\|' makes the C preprocessor recognize `\|\c -.B #pragma weak\c -\&\|' -.TP -\ \ \ \(bu -`\|\c -.B \-msvr4\c -\&\|' makes GCC issue additional declaration directives used in -SVr4. -.PP -`\|\c -.B \-msvr3\c -\&\|' is the default for all m88K configurations except -the SVr4 configuration. -.TP -.B \-mtrap\-large\-shift -.TP -.B \-mhandle\-large\-shift -Include code to detect bit-shifts of more than 31 bits; respectively, -trap such shifts or emit code to handle them properly. By default GCC -makes no special provision for large bit shifts. -.TP -.B \-muse\-div\-instruction -Very early models of the 88K architecture didn't have a divide -instruction, so GCC avoids that instruction by default. Use this option -to specify that it's safe to use the divide instruction. -.TP -.B \-mversion\-03.00 -In the DG/UX configuration, there are two flavors of SVr4. This option -modifies -.B \-msvr4 -to select whether the hybrid-COFF or real-ELF -flavor is used. All other configurations ignore this option. -.TP -.B \-mwarn\-passed\-structs -Warn when a function passes a struct as an argument or result. -Structure-passing conventions have changed during the evolution of the C -language, and are often the source of portability problems. By default, -GCC issues no such warning. -.PP -These options are defined for the IBM RS6000: -.PP -.B \-mfp\-in\-toc -.TP -.B \-mno\-fp\-in\-toc -Control whether or not floating-point constants go in the Table of -Contents (TOC), a table of all global variable and function addresses. By -default GCC puts floating-point constants there; if the TOC overflows, -`\|\c -.B \-mno\-fp\-in\-toc\c -\&\|' will reduce the size of the TOC, which may avoid -the overflow. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the IBM RT PC: -.TP -.B \-min\-line\-mul -Use an in-line code sequence for integer multiplies. This is the -default. -.TP -.B \-mcall\-lib\-mul -Call \c -.B lmul$$\c -\& for integer multiples. -.TP -.B \-mfull\-fp\-blocks -Generate full-size floating point data blocks, including the minimum -amount of scratch space recommended by IBM. This is the default. -.TP -.B \-mminimum\-fp\-blocks -Do not include extra scratch space in floating point data blocks. This -results in smaller code, but slower execution, since scratch space must -be allocated dynamically. -.TP -.B \-mfp\-arg\-in\-fpregs -Use a calling sequence incompatible with the IBM calling convention in -which floating point arguments are passed in floating point registers. -Note that \c -.B varargs.h\c -\& and \c -.B stdargs.h\c -\& will not work with -floating point operands if this option is specified. -.TP -.B \-mfp\-arg\-in\-gregs -Use the normal calling convention for floating point arguments. This is -the default. -.TP -.B \-mhc\-struct\-return -Return structures of more than one word in memory, rather than in a -register. This provides compatibility with the MetaWare HighC (hc) -compiler. Use `\|\c -.B \-fpcc\-struct\-return\c -\&\|' for compatibility with the -Portable C Compiler (pcc). -.TP -.B \-mnohc\-struct\-return -Return some structures of more than one word in registers, when -convenient. This is the default. For compatibility with the -IBM-supplied compilers, use either `\|\c -.B \-fpcc\-struct\-return\c -\&\|' or -`\|\c -.B \-mhc\-struct\-return\c -\&\|'. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the MIPS family of computers: -.TP -.BI "\-mcpu=" "cpu-type" -Assume the defaults for the machine type -.I cpu-type -when -scheduling instructions. The default -.I cpu-type -is -.BR default , -which picks the longest cycles times for any of the machines, in order -that the code run at reasonable rates on all MIPS cpu's. Other -choices for -.I cpu-type -are -.BR r2000 , -.BR r3000 , -.BR r4000 , -and -.BR r6000 . -While picking a specific -.I cpu-type -will schedule things appropriately for that particular chip, the -compiler will not generate any code that does not meet level 1 of the -MIPS ISA (instruction set architecture) without the -.B \-mips2 -or -.B \-mips3 -switches being used. -.TP -.B \-mips2 -Issue instructions from level 2 of the MIPS ISA (branch likely, square -root instructions). The -.B \-mcpu=r4000 -or -.B \-mcpu=r6000 -switch must be used in conjunction with -.BR \-mips2 . -.TP -.B \-mips3 -Issue instructions from level 3 of the MIPS ISA (64 bit instructions). -The -.B \-mcpu=r4000 -switch must be used in conjunction with -.BR \-mips2 . -.TP -.B \-mint64 -.TP -.B \-mlong64 -.TP -.B \-mlonglong128 -These options don't work at present. -.TP -.B \-mmips\-as -Generate code for the MIPS assembler, and invoke -.B mips\-tfile -to add normal debug information. This is the default for all -platforms except for the OSF/1 reference platform, using the OSF/rose -object format. If any of the -.BR \-ggdb , -.BR \-gstabs , -or -.B \-gstabs+ -switches are used, the -.B mips\-tfile -program will encapsulate the stabs within MIPS ECOFF. -.TP -.B \-mgas -Generate code for the GNU assembler. This is the default on the OSF/1 -reference platform, using the OSF/rose object format. -.TP -.B \-mrnames -.TP -.B \-mno\-rnames -The -.B \-mrnames -switch says to output code using the MIPS software names for the -registers, instead of the hardware names (ie, -.B a0 -instead of -.BR $4 ). -The GNU assembler does not support the -.B \-mrnames -switch, and the MIPS assembler will be instructed to run the MIPS C -preprocessor over the source file. The -.B \-mno\-rnames -switch is default. -.TP -.B \-mgpopt -.TP -.B \-mno\-gpopt -The -.B \-mgpopt -switch says to write all of the data declarations before the -instructions in the text section, to all the MIPS assembler to -generate one word memory references instead of using two words for -short global or static data items. This is on by default if -optimization is selected. -.TP -.B \-mstats -.TP -.B \-mno\-stats -For each non-inline function processed, the -.B \-mstats -switch causes the compiler to emit one line to the standard error file -to print statistics about the program (number of registers saved, -stack size, etc.). -.TP -.B \-mmemcpy -.TP -.B \-mno\-memcpy -The -.B \-mmemcpy -switch makes all block moves call the appropriate string function -.RB ( memcpy -or -.BR bcopy ) -instead of possibly generating inline code. -.TP -.B \-mmips\-tfile -.TP -.B \-mno\-mips\-tfile -The -.B \-mno\-mips\-tfile -switch causes the compiler not postprocess the object file with the -.B mips\-tfile -program, after the MIPS assembler has generated it to add debug -support. If -.B mips\-tfile -is not run, then no local variables will be available to the debugger. -In addition, -.B stage2 -and -.B stage3 -objects will have the temporary file names passed to the assembler -embedded in the object file, which means the objects will not compare -the same. -.TP -.B \-msoft\-float -Generate output containing library calls for floating point. -.I -WARNING: -the requisite libraries are not part of GNU CC. Normally the -facilities of the machine's usual C compiler are used, but this can't -be done directly in cross-compilation. You must make your own -arrangements to provide suitable library functions for cross-compilation. -.TP -.B \-mhard\-float -Generate output containing floating point instructions. This is the -default if you use the unmodified sources. -.TP -.B \-mfp64 -Assume that the -.B FR -bit in the status word is on, and that there are 32 64-bit floating -point registers, instead of 32 32-bit floating point registers. You -must also specify the -.B \-mcpu=r4000 -and -.B \-mips3 -switches. -.TP -.B \-mfp32 -Assume that there are 32 32-bit floating point registers. This is the -default. -.PP -.B \-mabicalls -.TP -.B \-mno\-abicalls -Emit (or do not emit) the -.BR \&.abicalls , -.BR \&.cpload , -and -.B \&.cprestore -pseudo operations that some System V.4 ports use for position -independent code. -.TP -.B \-mhalf\-pic -.TP -.B \-mno\-half\-pic -The -.B \-mhalf\-pic -switch says to put pointers to extern references into the data section -and load them up, rather than put the references in the text section. -This option does not work at present. -.B -.BI \-G num -Put global and static items less than or equal to -.I num -bytes into the small data or bss sections instead of the normal data -or bss section. This allows the assembler to emit one word memory -reference instructions based on the global pointer -.RB ( gp -or -.BR $28 ), -instead of the normal two words used. By default, -.I num -is 8 when the MIPS assembler is used, and 0 when the GNU -assembler is used. The -.BI \-G num -switch is also passed to the assembler and linker. All modules should -be compiled with the same -.BI \-G num -value. -.TP -.B \-nocpp -Tell the MIPS assembler to not run its preprocessor over user -assembler files (with a `\|\c -.B .s\c -\&\|' suffix) when assembling them. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the Intel 80386 family of computers: -.TP -.B \-m486 -.TP -.B \-mno\-486 -Control whether or not code is optimized for a 486 instead of an -386. Code generated for a 486 will run on a 386 and vice versa. -.TP -.B \-mpentium -Synonym for -.B \-mcpu=pentium -.TP -.B \-mpentiumpro -Synonym for -.B \-mcpu=pentiumpro -.TP -.B \-mcpu=\fIcpu type\fP -Assume the defaults for the machine type CPU TYPE when scheduling instructions. -The choices for CPU TYPE are: -.B i386, -.B i486, -.B i586 -(pentium), -.B pentium, -.B i686 -(pentiumpro), -and -.B pentiumpro. -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 -.B \-march=\fIcpu type\fP -option being used. -.TP -.B \-march=\fIcpu type\fP -Generate instructions for the machine type CPU TYPE. -The choices for CPU TYPE are: -.B i386, -.B i486, -.B pentium, -and -.B pentiumpro. -Specifying -.B \-march=\fIcpu type\fP -implies -.B \-mcpu=\fIcpu type\fP. -.TP -.B \-msoft\-float -Generate output containing library calls for floating point. -.I Warning: -the requisite libraries are not part of GNU CC. -Normally the facilities of the machine's usual C compiler are used, but -this can't be done directly in cross-compilation. You must make your -own arrangements to provide suitable library functions for -cross-compilation. -.Sp -On machines where a function returns floating point results in the 80387 -register stack, some floating point opcodes may be emitted even if -`\|\c -.B \-msoft-float\c -\&\|' is used. -.TP -.B \-mno-fp-ret-in-387 -Do not use the FPU registers for return values of functions. -.Sp -The usual calling convention has functions return values of types -.B float\c -\& and \c -.B double\c -\& in an FPU register, even if there -is no FPU. The idea is that the operating system should emulate -an FPU. -.Sp -The option `\|\c -.B \-mno-fp-ret-in-387\c -\&\|' causes such values to be returned -in ordinary CPU registers instead. -.TP -.B \-mprofiler-epilogue -.TP -.B \-mno-profiler-epilogue -Generate extra code to write profile information for function exits. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the HPPA family of computers: -.TP -.B \-mpa-risc-1-0 -Generate code for a PA 1.0 processor. -.TP -.B \-mpa-risc-1-1 -Generate code for a PA 1.1 processor. -.TP -.B \-mkernel -Generate code which is suitable for use in kernels. Specifically, avoid -.B add\c -\& instructions in which one of the arguments is the DP register; -generate \c -.B addil\c -\& instructions instead. This avoids a rather serious -bug in the HP-UX linker. -.TP -.B \-mshared-libs -Generate code that can be linked against HP-UX shared libraries. This option -is not fully function yet, and is not on by default for any PA target. Using -this option can cause incorrect code to be generated by the compiler. -.TP -.B \-mno-shared-libs -Don't generate code that will be linked against shared libraries. This is -the default for all PA targets. -.TP -.B \-mlong-calls -Generate code which allows calls to functions greater than 256K away from -the caller when the caller and callee are in the same source file. Do -not turn this option on unless code refuses to link with \*(lqbranch out of -range errors\*('' from the linker. -.TP -.B \-mdisable-fpregs -Prevent floating point registers from being used in any manner. This is -necessary for compiling kernels which perform lazy context switching of -floating point registers. If you use this option and attempt to perform -floating point operations, the compiler will abort. -.TP -.B \-mdisable-indexing -Prevent the compiler from using indexing address modes. This avoids some -rather obscure problems when compiling MIG generated code under MACH. -.TP -.B \-mtrailing-colon -Add a colon to the end of label definitions (for ELF assemblers). -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the Intel 80960 family of computers: -.TP -.BI "\-m" "cpu-type" -Assume the defaults for the machine type -.I cpu-type -for instruction and addressing-mode availability and alignment. -The default -.I cpu-type -is -.BR kb ; -other choices are -.BR ka , -.BR mc , -.BR ca , -.BR cf , -.BR sa , -and -.BR sb . -.TP -.B \-mnumerics -.TP -.B \-msoft\-float -The -.B \-mnumerics -option indicates that the processor does support -floating-point instructions. The -.B \-msoft\-float -option indicates -that floating-point support should not be assumed. -.TP -.B \-mleaf\-procedures -.TP -.B \-mno\-leaf\-procedures -Do (or do not) attempt to alter leaf procedures to be callable with the -.I bal -instruction as well as -.IR call . -This will result in more -efficient code for explicit calls when the -.I bal -instruction can be -substituted by the assembler or linker, but less efficient code in other -cases, such as calls via function pointers, or using a linker that doesn't -support this optimization. -.TP -.B \-mtail\-call -.TP -.B \-mno\-tail\-call -Do (or do not) make additional attempts (beyond those of the -machine-independent portions of the compiler) to optimize tail-recursive -calls into branches. You may not want to do this because the detection of -cases where this is not valid is not totally complete. The default is -.BR \-mno\-tail\-call . -.TP -.B \-mcomplex\-addr -.TP -.B \-mno\-complex\-addr -Assume (or do not assume) that the use of a complex addressing mode is a -win on this implementation of the i960. Complex addressing modes may not -be worthwhile on the K-series, but they definitely are on the C-series. -The default is currently -.B \-mcomplex\-addr -for all processors except -the CB and CC. -.TP -.B \-mcode\-align -.TP -.B \-mno\-code\-align -Align code to 8-byte boundaries for faster fetching (or don't bother). -Currently turned on by default for C-series implementations only. -.TP -.B \-mic\-compat -.TP -.B \-mic2.0\-compat -.TP -.B \-mic3.0\-compat -Enable compatibility with iC960 v2.0 or v3.0. -.TP -.B \-masm\-compat -.TP -.B \-mintel\-asm -Enable compatibility with the iC960 assembler. -.TP -.B \-mstrict\-align -.TP -.B \-mno\-strict\-align -Do not permit (do permit) unaligned accesses. -.TP -.B \-mold\-align -Enable structure-alignment compatibility with Intel's gcc release version -1.3 (based on gcc 1.37). Currently this is buggy in that -.B #pragma align 1 -is always assumed as well, and cannot be turned off. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the DEC Alpha implementations: -.TP -.B \-mno-soft-float -.TP -.B \-msoft-float -Use (do not use) the hardware floating-point instructions for -floating-point operations. When \c -.B \-msoft-float\c -\& is specified, -functions in `\|\c -.B libgcc1.c\c -\&\|' will be used to perform floating-point -operations. Unless they are replaced by routines that emulate the -floating-point operations, or compiled in such a way as to call such -emulations routines, these routines will issue floating-point -operations. If you are compiling for an Alpha without floating-point -operations, you must ensure that the library is built so as not to call -them. -.Sp -Note that Alpha implementations without floating-point operations are -required to have floating-point registers. -.TP -.B \-mfp-reg -.TP -.B \-mno-fp-regs -Generate code that uses (does not use) the floating-point register set. -.B \-mno-fp-regs\c -\& implies \c -.B \-msoft-float\c -\&. If the floating-point -register set is not used, floating point operands are passed in integer -registers as if they were integers and floating-point results are passed -in $0 instead of $f0. This is a non-standard calling sequence, so any -function with a floating-point argument or return value called by code -compiled with \c -.B \-mno-fp-regs\c -\& must also be compiled with that -option. -.Sp -A typical use of this option is building a kernel that does not use, -and hence need not save and restore, any floating-point registers. -.PP -These additional options are available on System V Release 4 for -compatibility with other compilers on those systems: -.TP -.B \-G -On SVr4 systems, \c -.B gcc\c -\& accepts the option `\|\c -.B \-G\c -\&\|' (and passes -it to the system linker), for compatibility with other compilers. -However, we suggest you use `\|\c -.B \-symbolic\c -\&\|' or `\|\c -.B \-shared\c -\&\|' as -appropriate, instead of supplying linker options on the \c -.B gcc -command line. -.TP -.B \-Qy -Identify the versions of each tool used by the compiler, in a -.B .ident\c -\& assembler directive in the output. -.TP -.B \-Qn -Refrain from adding \c -.B .ident\c -\& directives to the output file (this is -the default). -.TP -.BI "\-YP," "dirs" -Search the directories \c -.I dirs\c -\&, and no others, for libraries -specified with `\|\c -.B \-l\c -\&\|'. You can separate directory entries in -.I dirs\c -\& from one another with colons. -.TP -.BI "\-Ym," "dir" -Look in the directory \c -.I dir\c -\& to find the M4 preprocessor. -The assembler uses this option. -.SH CODE GENERATION OPTIONS -These machine-independent options control the interface conventions -used in code generation. -.PP -Most of them begin with `\|\c -\-f\c -\&\|'. These options have both positive and negative forms; the negative form -of `\|\c -.B \-ffoo\c -\&\|' would be `\|\c -.B \-fno\-foo\c -\&\|'. In the table below, only -one of the forms is listed\(em\&the one which is not the default. You -can figure out the other form by either removing `\|\c -.B no\-\c -\&\|' or adding -it. -.TP -.B \-fnonnull\-objects -Assume that objects reached through references are not null -(C++ only). -.Sp -Normally, GNU C++ makes conservative assumptions about objects reached -through references. For example, the compiler must check that \c -.B a -is not null in code like the following: -.Sp -obj &a = g (); -a.f (2); -.Sp -Checking that references of this sort have non-null values requires -extra code, however, and it is unnecessary for many programs. You can -use `\|\c -.B \-fnonnull-objects\c -\&\|' to omit the checks for null, if your -program doesn't require checking. -.TP -.B \-fpcc\-struct\-return -Use the same convention for returning \c -.B struct\c -\& and \c -.B union -values that is used by the usual C compiler on your system. This -convention is less efficient for small structures, and on many -machines it fails to be reentrant; but it has the advantage of -allowing intercallability between GCC-compiled code and PCC-compiled -code. -.TP -.B \-freg\-struct\-return -Use the convention that -.B struct -and -.B union -values are returned in registers when possible. This is more -efficient for small structures than -.BR \-fpcc\-struct\-return . -.Sp -If you specify neither -.B \-fpcc\-struct\-return -nor -.BR \-freg\-struct\-return , -GNU CC defaults to whichever convention is standard for the target. -If there is no standard convention, GNU CC defaults to -.BR \-fpcc\-struct\-return . -.TP -.B \-fshort\-enums -Allocate to an \c -.B enum\c -\& type only as many bytes as it needs for the -declared range of possible values. Specifically, the \c -.B enum\c -\& type -will be equivalent to the smallest integer type which has enough room. -.TP -.B \-fshort\-double -Use the same size for -.B double -as for -.B float -\&. -.TP -.B \-fshared\-data -Requests that the data and non-\c -.B const\c -\& variables of this -compilation be shared data rather than private data. The distinction -makes sense only on certain operating systems, where shared data is -shared between processes running the same program, while private data -exists in one copy per process. -.TP -.B \-fno\-common -Allocate even uninitialized global variables in the bss section of the -object file, rather than generating them as common blocks. This has the -effect that if the same variable is declared (without \c -.B extern\c -\&) 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. -.TP -.B \-fno\-ident -Ignore the `\|\c -.B #ident\c -\&\|' directive. -.TP -.B \-fno\-gnu\-linker -Do not output global initializations (such as C++ constructors and -destructors) in the form used by the GNU linker (on systems where the GNU -linker is the standard method of handling them). Use this option when -you want to use a non-GNU linker, which also requires using the -.B collect2\c -\& program to make sure the system linker includes -constructors and destructors. (\c -.B collect2\c -\& is included in the GNU CC -distribution.) For systems which \c -.I must\c -\& use \c -.B collect2\c -\&, the -compiler driver \c -.B gcc\c -\& is configured to do this automatically. -.TP -.B \-finhibit-size-directive -Don't output a \c -.B .size\c -\& 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 `\|\c -.B crtstuff.c\c -\&\|'; you should not need to use it -for anything else. -.TP -.B \-fverbose-asm -Put extra commentary information in the generated assembly code to -make it more readable. This option is generally only of use to those -who actually need to read the generated assembly code (perhaps while -debugging the compiler itself). -.TP -.B \-fvolatile -Consider all memory references through pointers to be volatile. -.TP -.B \-fvolatile\-global -Consider all memory references to extern and global data items to -be volatile. -.TP -.B \-fpic -If supported for the target machines, generate position-independent code, -suitable for use in a shared library. -.TP -.B \-fPIC -If supported for the target machine, emit position-independent code, -suitable for dynamic linking, even if branches need large displacements. -.TP -.BI "\-ffixed\-" "reg" -Treat the register named \c -.I reg\c -\& as a fixed register; generated code -should never refer to it (except perhaps as a stack pointer, frame -pointer or in some other fixed role). -.Sp -.I reg\c -\& must be the name of a register. The register names accepted -are machine-specific and are defined in the \c -.B REGISTER_NAMES -macro in the machine description macro file. -.Sp -This flag does not have a negative form, because it specifies a -three-way choice. -.TP -.BI "\-fcall\-used\-" "reg" -Treat the register named \c -.I reg\c -\& as an allocable register that is -clobbered by function calls. It may be allocated for temporaries or -variables that do not live across a call. Functions compiled this way -will not save and restore the register \c -.I reg\c -\&. -.Sp -Use of this flag for a register that has a fixed pervasive role in the -machine's execution model, such as the stack pointer or frame pointer, -will produce disastrous results. -.Sp -This flag does not have a negative form, because it specifies a -three-way choice. -.TP -.BI "\-fcall\-saved\-" "reg" -Treat the register named \c -.I reg\c -\& as an allocable register saved by -functions. It may be allocated even for temporaries or variables that -live across a call. Functions compiled this way will save and restore -the register \c -.I reg\c -\& if they use it. -.Sp -Use of this flag for a register that has a fixed pervasive role in the -machine's execution model, such as the stack pointer or frame pointer, -will produce disastrous results. -.Sp -A different sort of disaster will result from the use of this flag for -a register in which function values may be returned. -.Sp -This flag does not have a negative form, because it specifies a -three-way choice. -.SH PRAGMAS -Two `\|\c -.B #pragma\c -\&\|' directives are supported for GNU C++, to permit using the same -header file for two purposes: as a definition of interfaces to a given -object class, and as the full definition of the contents of that object class. -.TP -.B #pragma interface -(C++ only.) -Use this directive in header files that define object classes, to save -space in most of the object files that use those classes. Normally, -local copies of certain information (backup copies of inline member -functions, debugging information, and the internal tables that -implement virtual functions) must be kept in each object file that -includes class definitions. You can use this pragma to avoid such -duplication. When a header file containing `\|\c -.B #pragma interface\c -\&\|' is included in a compilation, this auxiliary information -will not be generated (unless the main input source file itself uses -`\|\c -.B #pragma implementation\c -\&\|'). Instead, the object files will contain references to be -resolved at link time. -.TP -.B #pragma implementation -.TP -\fB#pragma implementation "\fP\fIobjects\fP\fB.h"\fP -(C++ only.) -Use this pragma in a main input file, when you want full output from -included header files to be generated (and made globally visible). -The included header file, in turn, should use `\|\c -.B #pragma interface\c -\&\|'. -Backup copies of inline member functions, debugging information, and -the internal tables used to implement virtual functions are all -generated in implementation files. -.Sp -If you use `\|\c -.B #pragma implementation\c -\&\|' with no argument, it applies to an include file with the same -basename as your source file; for example, in `\|\c -.B allclass.cc\c -\&\|', `\|\c -.B #pragma implementation\c -\&\|' by itself is equivalent to `\|\c -.B -#pragma implementation "allclass.h"\c -\&\|'. Use the string argument if you want a single implementation -file to include code from multiple header files. -.Sp -There is no way to split up the contents of a single header file into -multiple implementation files. -.SH FILES -.nf -.ta \w'LIBDIR/g++\-include 'u -file.c C source file -file.h C header (preprocessor) file -file.i preprocessed C source file -file.C C++ source file -file.cc C++ source file -file.cxx C++ source file -file.m Objective-C source file -file.s assembly language file -file.o object file -a.out link edited output -\fITMPDIR\fR/cc\(** temporary files -\fILIBDIR\fR/cpp preprocessor -\fILIBDIR\fR/cc1 compiler for C -\fILIBDIR\fR/cc1plus compiler for C++ -\fILIBDIR\fR/collect linker front end needed on some machines -\fILIBDIR\fR/libgcc.a GCC subroutine library -/lib/crt[01n].o start-up routine -\fILIBDIR\fR/ccrt0 additional start-up routine for C++ -/lib/libc.a standard C library, see -.IR intro (3) -/usr/include standard directory for \fB#include\fP files -\fILIBDIR\fR/include standard gcc directory for \fB#include\fP files -\fILIBDIR\fR/g++\-include additional g++ directory for \fB#include\fP -.Sp -.fi -.I LIBDIR -is usually -.B /usr/local/lib/\c -.IR machine / version . -.br -.I TMPDIR -comes from the environment variable -.B TMPDIR -(default -.B /usr/tmp -if available, else -.B /tmp\c -\&). -.SH "SEE ALSO" -as(1), cpp(1), gdb(1), ld(1) -.br -.RB "`\|" gcc "\|', `\|" cpp \|', -.RB "`\|" as "\|', `\|" ld \|', -and -.RB `\| gdb \|' -entries in -.B info\c -\&. -.br -.I -Using and Porting GNU CC (for version 2.0)\c -, Richard M. Stallman; -.I -The C Preprocessor\c -, Richard M. Stallman; -.I -Debugging with GDB: the GNU Source-Level Debugger\c -, Richard M. Stallman and Roland H. Pesch; -.I -Using as: the GNU Assembler\c -, Dean Elsner, Jay Fenlason & friends; -.I -ld: the GNU linker\c -, Steve Chamberlain and Roland Pesch. -.SH BUGS -For instructions on reporting bugs, see the GCC manual. -.SH COPYING -Copyright -.if t \(co -1991, 1992, 1993 Free Software Foundation, Inc. -.PP -Permission is granted to make and distribute verbatim copies of -this manual provided the copyright notice and this permission notice -are preserved on all copies. -.PP -Permission is granted to copy and distribute modified versions of this -manual under the conditions for verbatim copying, provided that the -entire resulting derived work is distributed under the terms of a -permission notice identical to this one. -.PP -Permission is granted to copy and distribute translations of this -manual into another language, under the above conditions for modified -versions, except that this permission notice may be included in -translations approved by the Free Software Foundation instead of in -the original English. -.SH AUTHORS -See the GNU CC Manual for the contributors to GNU CC. |