diff options
| author | Joseph Myers <jsm28@cam.ac.uk> | 2001-06-08 20:42:28 +0100 |
|---|---|---|
| committer | Joseph Myers <jsm28@gcc.gnu.org> | 2001-06-08 20:42:28 +0100 |
| commit | cd3bb27790771150d4ab39e5b3b0094bafe0cd19 (patch) | |
| tree | 0adad3721c3db479eead6125fd982afcb2f534c4 | |
| parent | 4c399c87ef6c1ad926fc039b89dff307119f7856 (diff) | |
| download | gcc-cd3bb27790771150d4ab39e5b3b0094bafe0cd19.zip gcc-cd3bb27790771150d4ab39e5b3b0094bafe0cd19.tar.gz gcc-cd3bb27790771150d4ab39e5b3b0094bafe0cd19.tar.bz2 | |
gcc.texi, [...]: Add index of command line options.
* doc/gcc.texi, doc/invoke.texi: Add index of command line
options. Use @opindex to index them rather than other indexing
commands. Use @var{...} instead of <...>. Avoid spaces in names
inside @var. Don't use @kindex to index escape sequences in
source code.
From-SVN: r43041
| -rw-r--r-- | gcc/ChangeLog | 8 | ||||
| -rw-r--r-- | gcc/doc/gcc.texi | 65 | ||||
| -rw-r--r-- | gcc/doc/invoke.texi | 1094 |
3 files changed, 1030 insertions, 137 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index eca3773..08fe5e0 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2001-06-08 Joseph S. Myers <jsm28@cam.ac.uk> + + * doc/gcc.texi, doc/invoke.texi: Add index of command line + options. Use @opindex to index them rather than other indexing + commands. Use @var{...} instead of <...>. Avoid spaces in names + inside @var. Don't use @kindex to index escape sequences in + source code. + 2001-06-08 Jason Merrill <jason_merrill@redhat.com> * stmt.c (current_nesting_level): New fn. diff --git a/gcc/doc/gcc.texi b/gcc/doc/gcc.texi index deb5210..b383c06 100644 --- a/gcc/doc/gcc.texi +++ b/gcc/doc/gcc.texi @@ -75,6 +75,9 @@ @settitle Porting the GNU Compiler Collection @end ifclear +@c Create a separate index for command line options. +@defindex op +@c Merge the standard indexes into a single one. @syncodeindex fn cp @syncodeindex vr cp @syncodeindex ky cp @@ -264,6 +267,7 @@ bugs. It corresponds to GCC version 3.1. * GNU Free Documentation License:: How you can copy and share this manual. * Contributors:: People who have contributed to GCC. +* Option Index:: Index to command line options. * Index:: Index of concepts and symbol names. @end menu @@ -369,6 +373,10 @@ with some exceptions, and possibly with some extensions. GCC supports three versions of the C standard, although support for the most recent version is not yet complete. +@opindex std +@opindex ansi +@opindex pedantic +@opindex pedantic-errors The original ANSI C standard (X3.159-1989) was ratified in 1989 and published in 1990. This standard was ratified as an ISO standard (ISO/IEC 9899:1990) later in 1990. There were no technical @@ -404,6 +412,7 @@ standard, use @samp{-std=c99} or @samp{-std=iso9899:1999}. (While in development, drafts of this standard version were referred to as @dfn{C9X}.) +@opindex traditional GCC also has some limited support for traditional (pre-ISO) C with the @samp{-traditional} option. This support may be of use for compiling some very old programs that have not been updated to ISO C, but should @@ -443,6 +452,7 @@ char *[])}. An OS kernel would be a freestanding environment; a program using the facilities of an operating system would normally be in a hosted implementation. +@opindex ffreestanding GNU CC aims towards being usable as a conforming freestanding implementation, or as the compiler for a conforming hosted implementation. By default, it will act as the compiler for a hosted @@ -547,6 +557,7 @@ edit the offending file and place the typedef in front of the prototypes. @item +@opindex pedantic-errors When @samp{-pedantic-errors} is specified, GCC will incorrectly give an error message when a function name is specified in an expression involving the comma operator. @@ -852,6 +863,7 @@ If you have this problem, set the LANG environment variable to "C" or "En_US". @item +@opindex fdollars-in-identifiers Even if you specify @samp{-fdollars-in-identifiers}, you cannot successfully use @samp{$} in identifiers on the RS/6000 due to a restriction in the IBM assembler. GAS supports these @@ -863,6 +875,7 @@ version 1.3.0.1 or later fixes this problem. You can obtain XLC-1.3.0.2 by requesting PTF 421749 from IBM. @item +@opindex mno-serialize-volatile There is an assembler bug in versions of DG/UX prior to 5.4.2.01 that occurs when the @samp{fldcr} instruction is used. GCC uses @samp{fldcr} on the 88100 to serialize volatile memory references. Use @@ -896,6 +909,7 @@ what options are used. @cindex RT PC @cindex IBM RT PC @item +@opindex mhc-struct-return On the IBM RT PC, the MetaWare HighC compiler (hc) uses a different convention for structure and union returning. Use the option @samp{-mhc-struct-return} to tell GCC to use a convention compatible @@ -904,6 +918,7 @@ with it. @cindex Vax calling convention @cindex Ultrix calling convention @item +@opindex fcall-saved On Ultrix, the Fortran compiler expects registers 2 through 5 to be saved by function calls. However, the C compiler uses conventions compatible with BSD Unix: registers 2 through 5 may be clobbered by function calls. @@ -945,6 +960,7 @@ sometimes reorders instructions incorrectly when optimization is turned on. If you think this may be happening to you, try using the GNU assembler; GAS version 2.1 supports ECOFF on Irix. +@opindex noasmopt Or use the @samp{-noasmopt} option when you compile GCC with itself, and then again when you compile your program. (This is a temporary kludge to turn off assembler optimization on Irix.) If this proves to @@ -1003,6 +1019,7 @@ MALLOC=gmalloc.o @node Incompatibilities @section Incompatibilities of GCC @cindex incompatibilities of GCC +@opindex traditional There are several noteworthy incompatibilities between GNU C and K&R (non-ISO) versions of C. The @samp{-traditional} option @@ -1031,6 +1048,7 @@ when passed a string constant as its format control string or input. This is because @code{sscanf} incorrectly tries to write into the string constant. Likewise @code{fscanf} and @code{scanf}. +@opindex fwritable-strings The best solution to these problems is to change the program to use @code{char}-array variables with initialization strings for these purposes instead of string constants. But if this is not possible, @@ -1089,6 +1107,7 @@ Here @code{a} may or may not be restored to its first value when the its first value is restored; otherwise, it keeps the last value stored in it. +@opindex W If you use the @samp{-W} option with the @samp{-O} option, you will get a warning when GCC thinks such a problem might be possible. @@ -1240,6 +1259,7 @@ structure and union returning. GCC on most of these machines uses a compatible convention when returning structures and unions in memory, but still returns small structures and unions in registers. +@opindex fpcc-struct-return You can tell GCC to use a compatible convention for all structure and union returning with the option @samp{-fpcc-struct-return}. @@ -1318,6 +1338,7 @@ does mean that there's nothing for us to do about them. @node Standard Libraries @section Standard Libraries +@opindex Wall GCC by itself attempts to be a conforming freestanding implementation. @xref{Standards,,Language Standards Supported by GCC}, for details of what this means. Beyond the library facilities required of such an @@ -1424,6 +1445,7 @@ hold a few more bits of precision than fit in a @code{double} in memory. Compiled code moves values between memory and floating point registers at its convenience, and moving them into memory truncates them. +@opindex ffloat-store You can partially avoid this problem by using the @samp{-ffloat-store} option (@pxref{Optimize Options}). @@ -1644,6 +1666,7 @@ you are removing prototypes that were made with @code{protoize}; if the program worked before without any prototypes, it will work again without them. +@opindex Wconversion You can find all the places where this problem might occur by compiling the program with the @samp{-Wconversion} option. It prints a warning whenever an argument is converted. @@ -1735,6 +1758,7 @@ clutter the program with a cast to @code{void} whenever the value isn't useful. @item +@opindex fshort-enums Making @samp{-fshort-enums} the default. This would cause storage layout to be incompatible with most other C @@ -1751,6 +1775,8 @@ The ISO C standard leaves it up to the implementation whether a bitfield declared plain @code{int} is signed or not. This in effect creates two alternative dialects of C. +@opindex fsigned-bitfields +@opindex funsigned-bitfields The GNU C compiler supports both dialects; you can specify the signed dialect with @samp{-fsigned-bitfields} and the unsigned dialect with @samp{-funsigned-bitfields}. However, this leaves open the question of @@ -1800,6 +1826,9 @@ explicitly in each bitfield whether it is signed or not. In this way, they write programs which have the same meaning in both C dialects.) @item +@opindex ansi +@opindex traditional +@opindex std Undefining @code{__STDC__} when @samp{-ansi} is not used. Currently, GCC defines @code{__STDC__} as long as you don't use @@ -1868,6 +1897,7 @@ However, the rationale here is that optimization of a nonempty loop cannot produce an empty one, which holds for C but is not always the case for C++. +@opindex funroll-loops Moreover, with @samp{-funroll-loops} small ``empty'' loops are already removed, so the current behavior is both sub-optimal and inconsistent and will change in the future. @@ -1907,6 +1937,7 @@ Making certain warnings into errors by default. Some ISO C testsuites report failure when the compiler does not produce an error message for a certain program. +@opindex pedantic-errors ISO C requires a ``diagnostic'' message for certain kinds of invalid programs, but a warning is defined by GCC to count as a diagnostic. If GCC produces a warning but not an error, that is correct ISO C support. @@ -1946,6 +1977,8 @@ warnings are issued only if you ask for them, with one of the @samp{-W} options (for instance, @samp{-Wall} requests a variety of useful warnings). +@opindex pedantic +@opindex pedantic-errors GCC always tries to compile your program if possible; it never gratuitously rejects a program whose meaning is clear merely because (for instance) it fails to conform to a standard. In some cases, @@ -3052,6 +3085,7 @@ go in a register: @cindex arithmetic libraries @cindex math libraries +@opindex msoft-float Code compiled with GCC may call certain library routines. Most of them handle arithmetic for which there are no instructions. This includes multiply and divide on some machines, and floating point @@ -3225,6 +3259,7 @@ the code to save a function's rtl for later inlining and to inline that rtl when the function is called. The header file @file{integrate.h} is also used for this purpose. +@opindex dr The option @samp{-dr} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.rtl} to the input file name. @@ -3251,6 +3286,7 @@ optimizations described above. The source file of this pass is @file{jump.c}. +@opindex dj The option @samp{-dj} causes a debugging dump of the RTL code after this pass is run for the first time. This dump file's name is made by appending @samp{.jump} to the input file name. @@ -3263,6 +3299,7 @@ is in @file{regclass.c}. @cindex jump threading @item +@opindex fthread-jumps Jump threading. This pass detects a condition jump that branches to an identical or inverse test. Such jumps can be @samp{threaded} through the second conditional test. The source code for this pass is in @@ -3277,6 +3314,7 @@ propagation. Its source file is @file{cse.c}. If constant propagation causes conditional jumps to become unconditional or to become no-ops, jump optimization is run again when CSE is finished. +@opindex ds The option @samp{-ds} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.cse} to the input file name. @@ -3293,6 +3331,7 @@ and copy propagation. The source file for this pass is gcse.c. +@opindex dG The option @samp{-dG} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.gcse} to the input file name. @@ -3307,15 +3346,18 @@ Its source files are @file{loop.c} and @file{unroll.c}, plus the header @file{loop.h} used for communication between them. Loop unrolling uses some functions in @file{integrate.c} and the header @file{integrate.h}. +@opindex dL The option @samp{-dL} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.loop} to the input file name. @item +@opindex frerun-cse-after-loop If @samp{-frerun-cse-after-loop} was enabled, a second common subexpression elimination pass is performed after the loop optimization pass. Jump threading is also done again at this time if it was specified. +@opindex dt The option @samp{-dt} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.cse2} to the input file name. @@ -3335,6 +3377,7 @@ This pass also deletes computations whose results are never used, and combines memory references with add or subtract instructions to make autoincrement or autodecrement addressing. +@opindex df The option @samp{-df} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.flow} to the input file name. If stupid register allocation is in use, this @@ -3348,6 +3391,7 @@ flow into single instructions. It combines the RTL expressions for the instructions by substitution, simplifies the result using algebra, and then attempts to match the result against the machine description. +@opindex dc The option @samp{-dc} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.combine} to the input file name. @@ -3360,6 +3404,7 @@ this reload would be a register to register move. It then attempts to change the registers used by the instruction to avoid the move instruction. +@opindex dN The option @samp{-dN} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.regmove} to the input file name. @@ -3377,6 +3422,7 @@ use of items that otherwise would cause pipeline stalls. Instruction scheduling is performed twice. The first time is immediately after instruction combination and the second is immediately after reload. +@opindex dS The option @samp{-dS} causes a debugging dump of the RTL code after this pass is run for the first time. The dump file's name is made by appending @samp{.sched} to the input file name. @@ -3395,6 +3441,7 @@ hard registers to pseudo registers that are used only within one basic block. Because the basic block is linear, it can use fast and powerful techniques to do a very good job. +@opindex dl The option @samp{-dl} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.lreg} to the input file name. @@ -3422,6 +3469,7 @@ instructions to save and restore call-clobbered registers around calls. Source files are @file{reload.c} and @file{reload1.c}, plus the header @file{reload.h} used for communication between them. +@opindex dg The option @samp{-dg} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.greg} to the input file name. @@ -3432,6 +3480,7 @@ the input file name. Instruction scheduling is repeated here to try to avoid pipeline stalls due to memory loads generated for spilled pseudo registers. +@opindex dR The option @samp{-dR} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.sched2} to the input file name. @@ -3442,6 +3491,7 @@ to the input file name. Jump optimization is repeated, this time including cross-jumping and deletion of no-op move instructions. +@opindex dJ The option @samp{-dJ} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.jump2} to the input file name. @@ -3453,6 +3503,7 @@ Delayed branch scheduling. This optional pass attempts to find instructions that can go into the delay slots of other instructions, usually jumps and calls. The source file name is @file{reorg.c}. +@opindex dd The option @samp{-dd} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.dbr} to the input file name. @@ -3473,6 +3524,7 @@ stack may be done at this point. Currently, this is supported only for the floating-point registers of the Intel 80387 coprocessor. The source file name is @file{reg-stack.c}. +@opindex dk The options @samp{-dk} causes a debugging dump of the RTL code after this pass. This dump file's name is made by appending @samp{.stack} to the input file name. @@ -4491,9 +4543,20 @@ Public License instead of this License. @include contrib.texi @c --------------------------------------------------------------------- -@c Node Index +@c Indexes @c --------------------------------------------------------------------- +@node Option Index +@unnumbered Option Index + +GCC's command line options are indexed here without any initial @samp{-} +or @samp{--}. Where an option has both positive and negative forms +(such as @option{-f@var{option}} and @option{-fno-@var{option}}), +relevant entries in the manual are indexed under the most appropriate +form; it may sometimes be useful to look up both forms. + +@printindex op + @node Index @unnumbered Index diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 692e79b..a0d0c93 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -107,6 +107,8 @@ only one of these two forms, whichever one is not the default. @c man end +@xref{Option Index}, for an index to GCC's options. + @menu * Option Summary:: Brief list of all options, without explanations. * Overall Options:: Controlling the kind of output: @@ -706,6 +708,7 @@ An object file to be fed straight into linking. Any file name with no recognized suffix is treated this way. @end table +@opindex x You can specify the input language explicitly with the @samp{-x} option: @table @gcctabopt @@ -730,6 +733,7 @@ handled according to their file name suffixes (as they are if @samp{-x} has not been used at all). @item -pass-exit-codes +@opindex pass-exit-codes Normally the @command{gcc} program will exit with the code of 1 if any phase of the compiler returns a non-success return code. If you specify @samp{-pass-exit-codes}, the @command{gcc} program will instead return with @@ -745,6 +749,7 @@ one of the options @samp{-c}, @samp{-S}, or @samp{-E} to say where @table @gcctabopt @item -c +@opindex c Compile or assemble the source files, but do not link. The linking stage simply is not done. The ultimate output is in the form of an object file for each source file. @@ -756,6 +761,7 @@ Unrecognized input files, not requiring compilation or assembly, are ignored. @item -S +@opindex S Stop after the stage of compilation proper; do not assemble. The output is in the form of an assembler code file for each non-assembler input file specified. @@ -766,6 +772,7 @@ replacing the suffix @samp{.c}, @samp{.i}, etc., with @samp{.s}. Input files that don't require compilation are ignored. @item -E +@opindex E Stop after the preprocessing stage; do not run the compiler proper. The output is in the form of preprocessed source code, which is sent to the standard output. @@ -774,6 +781,7 @@ Input files which don't require preprocessing are ignored. @cindex output file option @item -o @var{file} +@opindex o Place output in file @var{file}. This applies regardless to whatever sort of output is being produced, whether it be an executable file, an object file, an assembler file or preprocessed C code. @@ -788,17 +796,20 @@ in @file{a.out}, the object file for @file{@var{source}.@var{suffix}} in all preprocessed C source on standard output.@refill @item -v +@opindex 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. @item -pipe +@opindex 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 is unable to read from a pipe; but the GNU assembler has no trouble. @item --help +@opindex help Print (on the standard output) a description of the command line options understood by @command{gcc}. If the @option{-v} option is also specified then @option{--help} will also be passed on to the various processes @@ -808,6 +819,7 @@ line options which have no documentation associated with them will also be displayed. @item --target-help +@opindex target-help Print (on the standard output) a description of target specific command line options for each tool. @end table @@ -858,6 +870,7 @@ from C, such as C++ and Objective C) that the compiler accepts: @cindex ANSI support @cindex ISO support @item -ansi +@opindex ansi In C mode, support all ISO C89 programs. In C++ mode, remove GNU extensions that conflict with ISO C++. @@ -895,6 +908,7 @@ built-in functions provided by GNU CC}, for details of the functions affected. @item -std= +@opindex std Determine the language standard. A value for this option must be provided; possible values are @@ -946,6 +960,7 @@ the @code{inline} keyword in ISO C99) are not disabled. these standard versions. @item -fno-asm +@opindex fno-asm Do not recognize @code{asm}, @code{inline} or @code{typeof} as a keyword, so that code can use these words as identifiers. You can use the keywords @code{__asm__}, @code{__inline__} and @code{__typeof__} @@ -959,6 +974,7 @@ switch only affects the @code{asm} and @code{typeof} keywords, since @code{inline} is a standard keyword in ISO C99. @item -fno-builtin +@opindex fno-builtin @cindex builtin functions Don't recognize builtin functions that do not begin with @samp{__builtin_} as prefix. @xref{Other Builtins,,Other built-in @@ -983,6 +999,7 @@ builtin functions to implement many functions (like @code{std::strchr}), so that you automatically get efficient code. @item -fhosted +@opindex fhosted @cindex hosted environment Assert that compilation takes place in a hosted environment. This implies @@ -992,6 +1009,7 @@ type of @code{int}. Examples are nearly everything except a kernel. This is equivalent to @samp{-fno-freestanding}. @item -ffreestanding +@opindex ffreestanding @cindex hosted environment Assert that compilation takes place in a freestanding environment. This @@ -1004,6 +1022,7 @@ This is equivalent to @samp{-fno-hosted}. freestanding and hosted environments. @item -trigraphs +@opindex trigraphs Support ISO C trigraphs. You don't want to know about this brain-damage. The @option{-ansi} option (and @option{-std} options for strict ISO C conformance) implies @option{-trigraphs}. @@ -1011,6 +1030,7 @@ strict ISO C conformance) implies @option{-trigraphs}. @cindex traditional C language @cindex C language, traditional @item -traditional +@opindex traditional Attempt to support some aspects of traditional C compilers. Specifically: @@ -1053,8 +1073,8 @@ All automatic variables not declared @code{register} are preserved by not declared @code{volatile} may be clobbered. @item -@kindex \x -@kindex \a +@cindex @samp{\x} +@cindex @samp{\a} @cindex escape sequences, traditional The character escape sequences @samp{\x} and @samp{\a} evaluate as the literal characters @samp{x} and @samp{a} respectively. Without @@ -1075,6 +1095,7 @@ The @samp{-traditional} option also enables @samp{-traditional-cpp}, which is described next. @item -traditional-cpp +@opindex traditional-cpp Attempt to support some aspects of traditional C preprocessors. Specifically: @@ -1116,11 +1137,13 @@ string constants can contain the newline character as typed.) @end itemize @item -fcond-mismatch +@opindex fcond-mismatch Allow conditional expressions with mismatched types in the second and third arguments. The value of such an expression is void. This option is not supported for C++. @item -funsigned-char +@opindex funsigned-char Let the type @code{char} be unsigned, like @code{unsigned char}. Each kind of machine has a default for what @code{char} should @@ -1139,6 +1162,7 @@ The type @code{char} is always a distinct type from each of is always just like one of those two. @item -fsigned-char +@opindex fsigned-char Let the type @code{char} be signed, like @code{signed char}. Note that this is equivalent to @samp{-fno-unsigned-char}, which is @@ -1158,6 +1182,10 @@ systems to compile files that include any system headers. @itemx -funsigned-bitfields @itemx -fno-signed-bitfields @itemx -fno-unsigned-bitfields +@opindex fsigned-bitfields +@opindex funsigned-bitfields +@opindex fno-signed-bitfields +@opindex fno-unsigned-bitfields These options control whether a bitfield is signed or unsigned, when the declaration does not use either @code{signed} or @code{unsigned}. By default, such a bitfield is signed, because this is consistent: the @@ -1167,6 +1195,7 @@ However, when @samp{-traditional} is used, bitfields are all unsigned no matter what. @item -fwritable-strings +@opindex 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. The option @samp{-traditional} also has @@ -1176,6 +1205,7 @@ Writing into string constants is a very bad idea; ``constants'' should be constant. @item -fallow-single-precision +@opindex fallow-single-precision Do not promote single precision math operations to double precision, even when compiling with @samp{-traditional}. @@ -1188,6 +1218,7 @@ precision, use this option. This option has no effect when compiling with ISO or GNU C conventions (the default). @item -fshort-wchar +@opindex fshort-wchar Override the underlying type for @samp{wchar_t} to be @samp{short unsigned int} instead of the default for the target. This option is useful for building programs to run under WINE. @@ -1217,10 +1248,12 @@ Here is a list of options that are @emph{only} for compiling C++ programs: @table @gcctabopt @item -fno-access-control +@opindex fno-access-control Turn off all access checking. This switch is mainly useful for working around bugs in the access control code. @item -fcheck-new +@opindex fcheck-new Check that the pointer returned by @code{operator new} is non-null before attempting to modify the storage allocated. The current Working Paper requires that @code{operator new} never return a null pointer, so @@ -1232,6 +1265,7 @@ An alternative to using this option is to specify that your (nothrow)}. @item -fconserve-space +@opindex fconserve-space Put uninitialized or runtime-initialized global variables into the common segment, as C does. This saves space in the executable at the cost of not diagnosing duplicate definitions. If you compile with this @@ -1243,6 +1277,7 @@ This option is no longer useful on most targets, now that support has been added for putting variables into BSS without making them common. @item -fno-const-strings +@opindex fno-const-strings Give string constants type @code{char *} instead of type @code{const char *}. By default, G++ uses type @code{const char *} as required by the standard. Even if you use @samp{-fno-const-strings}, you cannot @@ -1254,6 +1289,7 @@ portability, you should structure your code so that it works with string constants that have type @code{const char *}. @item -fdollars-in-identifiers +@opindex fdollars-in-identifiers Accept @samp{$} in identifiers. You can also explicitly prohibit use of @samp{$} with the option @samp{-fno-dollars-in-identifiers}. (GNU C allows @samp{$} by default on most target systems, but there are a few exceptions.) @@ -1261,18 +1297,21 @@ Traditional C allowed the character @samp{$} to form part of identifiers. However, ISO C and C++ forbid @samp{$} in identifiers. @item -fno-elide-constructors +@opindex fno-elide-constructors The C++ standard allows an implementation to omit creating a temporary which is only used to initialize another object of the same type. Specifying this option disables that optimization, and forces g++ to call the copy constructor in all cases. @item -fno-enforce-eh-specs +@opindex fno-enforce-eh-specs Don't check for violation of exception specifications at runtime. This option violates the C++ standard, but may be useful for reducing code size in production builds, much like defining @samp{NDEBUG}. The compiler will still optimize based on the exception specifications. @item -fexternal-templates +@opindex fexternal-templates Cause template instantiations to obey @samp{#pragma interface} and @samp{implementation}; template instances are emitted or not according to the location of the template definition. @xref{Template @@ -1281,6 +1320,7 @@ Instantiation}, for more information. This option is deprecated. @item -falt-external-templates +@opindex falt-external-templates Similar to -fexternal-templates, but template instances are emitted or not according to the place where they are first instantiated. @xref{Template Instantiation}, for more information. @@ -1289,6 +1329,8 @@ This option is deprecated. @item -ffor-scope @itemx -fno-for-scope +@opindex ffor-scope +@opindex fno-for-scope If -ffor-scope is specified, the scope of variables declared in a @i{for-init-statement} is limited to the @samp{for} loop itself, as specified by the C++ standard. @@ -1302,11 +1344,13 @@ but to allow and give a warning for old-style code that would otherwise be invalid, or have different behavior. @item -fno-gnu-keywords +@opindex fno-gnu-keywords Do not recognize @code{typeof} as a keyword, so that code can use this word as an identifier. You can use the keyword @code{__typeof__} instead. @samp{-ansi} implies @samp{-fno-gnu-keywords}. @item -fhonor-std +@opindex fhonor-std Treat the @code{namespace std} as a namespace, instead of ignoring it. For compatibility with earlier versions of g++, the compiler will, by default, ignore @code{namespace-declarations}, @@ -1314,51 +1358,61 @@ by default, ignore @code{namespace-declarations}, @code{namespace-names}, if they involve @code{std}. @item -fno-implicit-templates +@opindex fno-implicit-templates Never emit code for non-inline templates which are instantiated implicitly (i.e. by use); only emit code for explicit instantiations. @xref{Template Instantiation}, for more information. @item -fno-implicit-inline-templates +@opindex fno-implicit-inline-templates Don't emit code for implicit instantiations of inline templates, either. The default is to handle inlines differently so that compiles with and without optimization will need the same set of explicit instantiations. @item -fno-implement-inlines +@opindex fno-implement-inlines To save space, do not emit out-of-line copies of inline functions controlled by @samp{#pragma implementation}. This will cause linker errors if these functions are not inlined everywhere they are called. @item -fms-extensions +@opindex fms-extensions Disable pedantic warnings about constructs used in MFC, such as implicit int and getting a pointer to member function via non-standard syntax. @item -fno-nonansi-builtins +@opindex fno-nonansi-builtins Disable builtin declarations of functions that are not mandated by ANSI/ISO C. These include @code{ffs}, @code{alloca}, @code{_exit}, @code{index}, @code{bzero}, @code{conjf}, and other related functions. @item -fno-operator-names +@opindex fno-operator-names Do not treat the operator name keywords @code{and}, @code{bitand}, @code{bitor}, @code{compl}, @code{not}, @code{or} and @code{xor} as synonyms as keywords. @item -fno-optional-diags +@opindex fno-optional-diags Disable diagnostics that the standard says a compiler does not need to issue. Currently, the only such diagnostic issued by g++ is the one for a name having multiple meanings within a class. @item -fpermissive +@opindex fpermissive Downgrade messages about nonconformant code from errors to warnings. By default, g++ effectively sets @samp{-pedantic-errors} without @samp{-pedantic}; this option reverses that. This behavior and this option are superseded by @samp{-pedantic}, which works as it does for GNU C. @item -frepo +@opindex frepo Enable automatic template instantiation. This option also implies @samp{-fno-implicit-templates}. @xref{Template Instantiation}, for more information. @item -fno-rtti +@opindex fno-rtti Disable generation of information about every class with virtual functions for use by the C++ runtime type identification features (@samp{dynamic_cast} and @samp{typeid}). If you don't use those parts @@ -1367,16 +1421,19 @@ exception handling uses the same information, but it will generate it as needed. @item -fstats +@opindex fstats Emit statistics about front-end processing at the end of the compilation. This information is generally only useful to the G++ development team. @item -ftemplate-depth-@var{n} +@opindex ftemplate-depth Set the maximum instantiation depth for template classes to @var{n}. A limit on the template instantiation depth is needed to detect endless recursions during template class instantiation. ANSI/ISO C++ conforming programs must not rely on a maximum depth greater than 17. @item -fuse-cxa-atexit +@opindex fuse-cxa-atexit Register destructors for objects with static storage duration with the @code{__cxa_atexit} function rather than the @code{atexit} function. This option is required for fully standards-compliant handling of static @@ -1384,6 +1441,7 @@ destructors, but will only work if your C library supports @code{__cxa_atexit}. @item -fvtable-gc +@opindex fvtable-gc Emit special relocations for vtables and virtual function references so that the linker can identify unused virtual functions and zero out vtable slots that refer to them. This is most useful with @@ -1394,6 +1452,7 @@ This optimization requires GNU as and GNU ld. Not all systems support this option. @samp{-Wl,--gc-sections} is ignored without @samp{-static}. @item -fno-weak +@opindex fno-weak Do not use weak symbol support, even if it is provided by the linker. By default, G++ will use weak symbols if they are available. This option exists only for testing, and should not be used by end-users; @@ -1401,6 +1460,7 @@ it will result in inferior code and has no benefits. This option may be removed in a future release of G++. @item -nostdinc++ +@opindex nostdinc++ Do not search for header files in the standard directories specific to C++, but do still search the other standard directories. (This option is used when building the C++ library.) @@ -1411,21 +1471,25 @@ have meanings only for C++ programs: @table @gcctabopt @item -fno-default-inline +@opindex fno-default-inline Do not assume @samp{inline} for functions defined inside a class scope. @xref{Optimize Options,,Options That Control Optimization}. Note that these functions will have linkage like inline functions; they just won't be inlined by default. @item -Wctor-dtor-privacy (C++ only) +@opindex Wctor-dtor-privacy Warn when a class seems unusable, because all the constructors or destructors in a class are private and the class has no friends or public static member functions. @item -Wnon-virtual-dtor (C++ only) +@opindex Wnon-virtual-dtor Warn when a class declares a non-virtual destructor that should probably be virtual, because it looks like the class will be used polymorphically. @item -Wreorder (C++ only) +@opindex Wreorder @cindex reordering, warning @cindex warning for reordering of member initializers Warn when the order of member initializers given in the code does not @@ -1448,15 +1512,18 @@ The following @samp{-W@dots{}} options are not affected by @samp{-Wall}. @table @gcctabopt @item -Weffc++ (C++ only) +@opindex Weffc++ Warn about violations of various style guidelines from Scott Meyers' @cite{Effective C++} books. If you use this option, you should be aware that the standard library headers do not obey all of these guidelines; you can use @samp{grep -v} to filter out those warnings. @item -Wno-deprecated (C++ only) +@opindex Wno-deprecated Do not warn about usage of deprecated features. @xref{Deprecated Features}. @item -Wno-non-template-friend (C++ only) +@opindex Wno-non-template-friend Disable warnings when non-templatized friend functions are declared within a template. With the advent of explicit template specification support in g++, if the name of the friend is an unqualified-id (ie, @@ -1472,12 +1539,14 @@ This new compiler behavior can be turned off with but disables the helpful warning. @item -Wold-style-cast (C++ only) +@opindex Wold-style-cast Warn if an old-style (C-style) cast is used within a C++ program. The new-style casts (@samp{static_cast}, @samp{reinterpret_cast}, and @samp{const_cast}) are less vulnerable to unintended effects, and much easier to grep for. @item -Woverloaded-virtual (C++ only) +@opindex Woverloaded-virtual @cindex overloaded virtual fn, warning @cindex warning for overloaded virtual fn Warn when a function declaration hides virtual functions from a @@ -1504,16 +1573,19 @@ b->f(); will fail to compile. @item -Wno-pmf-conversions (C++ only) +@opindex Wno-pmf-conversions Disable the diagnostic for converting a bound pointer to member function to a plain pointer. @item -Wsign-promo (C++ only) +@opindex Wsign-promo Warn when overload resolution chooses a promotion from unsigned or enumeral type to a signed type over a conversion to an unsigned type of the same size. Previous versions of g++ would try to preserve unsignedness, but the standard mandates the current behavior. @item -Wsynth (C++ only) +@opindex Wsynth @cindex warning for synthesized methods @cindex synthesized methods, warning Warn when g++'s synthesis behavior does not match that of cfront. For @@ -1561,27 +1633,33 @@ programs: @table @gcctabopt @item -fconstant-string-class=@var{class name} +@opindex fconstant-string-class Use @var{class name} as the name of the class to instantiate for each literal string specified with the syntax @code{@@"..."}. The default class name is @code{NXConstantString}. @item -fgnu-runtime +@opindex fgnu-runtime Generate object code compatible with the standard GNU Objective-C runtime. This is the default for most types of systems. @item -fnext-runtime +@opindex fnext-runtime Generate output compatible with the NeXT runtime. This is the default for NeXT-based systems, including Darwin and Mac OS X. @item -gen-decls +@opindex gen-decls Dump interface declarations for all classes seen in the source file to a file named @file{@var{sourcename}.decl}. @item -Wno-protocol +@opindex Wno-protocol Do not warn if methods required by a protocol are not implemented in the class adopting it. @item -Wselector +@opindex Wselector Warn if a selector has multiple methods of different types defined. @c not documented because only avail via -Wp @@ -1605,12 +1683,14 @@ the remaining front-ends would be able to digest them correctly. @table @gcctabopt @item -fmessage-length=@var{n} +@opindex fmessage-length Try to format error messages so that they fit on lines of about @var{n} characters. The default is 72 characters for g++ and 0 for the rest of the front-ends supported by GCC. If @var{n} is zero, then no line-wrapping will be done; each error message will appear on a single line. +@opindex fdiagnostics-show-location @item -fdiagnostics-show-location=once Only meaningful in line-wrapping mode. Instructs the diagnostic messages reporter to emit @emph{once} source location information; that is, in @@ -1650,9 +1730,11 @@ These options control the amount and kinds of warnings produced by GCC: @table @gcctabopt @cindex syntax checking @item -fsyntax-only +@opindex fsyntax-only Check the code for syntax errors, but don't do anything beyond that. @item -pedantic +@opindex pedantic Issue all the warnings demanded by strict ISO C and ISO C++; reject all programs that use forbidden extensions, and some other programs that do not follow ISO C and ISO C++. For ISO C, follows the @@ -1693,25 +1775,31 @@ features the compiler supports with the given option, and there would be nothing to warn about.) @item -pedantic-errors +@opindex pedantic-errors Like @samp{-pedantic}, except that errors are produced rather than warnings. @item -w +@opindex w Inhibit all warning messages. @item -Wno-import +@opindex Wno-import Inhibit warning messages about the use of @samp{#import}. @item -Wchar-subscripts +@opindex Wchar-subscripts Warn if an array subscript has type @code{char}. This is a common cause of error, as programmers often forget that this type is signed on some machines. @item -Wcomment +@opindex Wcomment Warn whenever a comment-start sequence @samp{/*} appears in a @samp{/*} comment, or whenever a Backslash-Newline appears in a @samp{//} comment. @item -Wformat +@opindex Wformat Check calls to @code{printf} and @code{scanf}, etc., to make sure that the arguments supplied have types appropriate to the format string specified, and that the conversions specified in the format string make @@ -1738,20 +1826,24 @@ aspects of format checking, the options @samp{-Wno-format-y2k}, not included in @samp{-Wall}. @item -Wno-format-y2k +@opindex Wno-format-y2k If @samp{-Wformat} is specified, do not warn about @code{strftime} formats which may yield only a two-digit year. @item -Wno-format-extra-args +@opindex Wno-format-extra-args If @samp{-Wformat} is specified, do not warn about excess arguments to a @code{printf} or @code{scanf} format function. The C standard specifies that such arguments are ignored. @item -Wformat-nonliteral +@opindex Wformat-nonliteral If @samp{-Wformat} is specified, also warn if the format string is not a string literal and so cannot be checked, unless the format function takes its format arguments as a @code{va_list}. @item -Wformat-security +@opindex Wformat-security If @samp{-Wformat} is specified, also warn about uses of format functions that represent possible security problems. At present, this warns about calls to @code{printf} and @code{scanf} functions where the @@ -1763,28 +1855,35 @@ in future warnings may be added to @samp{-Wformat-security} that are not included in @samp{-Wformat-nonliteral}.) @item -Wformat=2 +@opindex Wformat=2 Enable @samp{-Wformat} plus format checks not included in @samp{-Wformat}. Currently equivalent to @samp{-Wformat -Wformat-nonliteral -Wformat-security}. @item -Wimplicit-int +@opindex Wimplicit-int Warn when a declaration does not specify a type. @item -Wimplicit-function-declaration @itemx -Werror-implicit-function-declaration +@opindex Wimplicit-function-declaration +@opindex Werror-implicit-function-declaration Give a warning (or error) whenever a function is used before being declared. @item -Wimplicit +@opindex Wimplicit Same as @samp{-Wimplicit-int} and @samp{-Wimplicit-function-}@* @samp{declaration}. @item -Wmain +@opindex Wmain Warn if the type of @samp{main} is suspicious. @samp{main} should be a function with external linkage, returning int, taking either zero arguments, two, or three arguments of appropriate types. @item -Wmissing-braces +@opindex Wmissing-braces Warn if an aggregate or union initializer is not fully bracketed. In the following example, the initializer for @samp{a} is not fully bracketed, but that for @samp{b} is fully bracketed. @@ -1795,11 +1894,13 @@ int b[2][2] = @{ @{ 0, 1 @}, @{ 2, 3 @} @}; @end smallexample @item -Wmultichar +@opindex Wmultichar Warn if a multicharacter constant (@samp{'FOOF'}) is used. Usually they indicate a typo in the user's code, as they have implementation-defined values, and should not be used in portable code. @item -Wparentheses +@opindex Wparentheses Warn if parentheses are omitted in certain contexts, such as when there is an assignment in a context where a truth value is expected, or when operators are nested whose precedence people @@ -1841,6 +1942,7 @@ the enclosing @code{if}. The resulting code would look like this: @end smallexample @item -Wsequence-point +@opindex Wsequence-point Warn about code that may have undefined semantics because of violations of sequence point rules in the C standard. @@ -1885,6 +1987,7 @@ and other related discussions may be found on our readings page @w{@uref{http://gcc.gnu.org/readings.html}}. @item -Wreturn-type +@opindex Wreturn-type Warn whenever a function is defined with a return-type that defaults to @code{int}. Also warn about any @code{return} statement with no return-value in a function whose return-type is not @code{void}. @@ -1894,6 +1997,7 @@ message, even when @samp{-Wno-return-type} is specified. The only exceptions are @samp{main} and functions defined in system headers. @item -Wswitch +@opindex Wswitch Warn whenever a @code{switch} statement has an index of enumeral type and lacks a @code{case} for one or more of the named codes of that enumeration. (The presence of a @code{default} label prevents this @@ -1901,26 +2005,31 @@ warning.) @code{case} labels outside the enumeration range also provoke warnings when this option is used. @item -Wtrigraphs +@opindex Wtrigraphs Warn if any trigraphs are encountered that might change the meaning of the program (trigraphs within comments are not warned about). @item -Wunused-function +@opindex Wunused-function Warn whenever a static function is declared but not defined or a non\-inline static function is unused. @item -Wunused-label +@opindex Wunused-label Warn whenever a label is declared but not used. To suppress this warning use the @samp{unused} attribute (@pxref{Variable Attributes}). @item -Wunused-parameter +@opindex Wunused-parameter Warn whenever a function parameter is unused aside from its declaration. To suppress this warning use the @samp{unused} attribute (@pxref{Variable Attributes}). @item -Wunused-variable +@opindex Wunused-variable Warn whenever a local variable or non-constant static variable is unused aside from its declaration @@ -1928,11 +2037,13 @@ To suppress this warning use the @samp{unused} attribute (@pxref{Variable Attributes}). @item -Wunused-value +@opindex Wunused-value Warn whenever a statement computes a result that is explicitly not used. To suppress this warning cast the expression to @samp{void}. @item -Wunused +@opindex Wunused All all the above @samp{-Wunused} options combined. In order to get a warning about an unused function parameter, you must @@ -1940,6 +2051,7 @@ either specify @samp{-W -Wunused} or separately specify @samp{-Wunused-parameter}. @item -Wuninitialized +@opindex Wuninitialized Warn if an automatic variable is used without first being initialized or if a variable may be clobbered by a @code{setjmp} call. @@ -2012,12 +2124,14 @@ you use that never return as @code{noreturn}. @xref{Function Attributes}. @item -Wreorder (C++ only) +@opindex Wreorder @cindex reordering, warning @cindex warning for reordering of member initializers Warn when the order of member initializers given in the code does not match the order in which they must be executed. For instance: @item -Wunknown-pragmas +@opindex Wunknown-pragmas @cindex warning for unknown pragmas @cindex unknown pragmas, warning @cindex pragmas, warning of unknown @@ -2027,12 +2141,14 @@ for unknown pragmas in system header files. This is not the case if the warnings were only enabled by the @samp{-Wall} command line option. @item -Wall +@opindex Wall All of the above @samp{-W} options combined. This enables all the warnings about constructions that some users consider questionable, and that are easy to avoid (or modify to prevent the warning), even in conjunction with macros. @item -Wsystem-headers +@opindex Wsystem-headers @cindex warnings from system headers @cindex system headers, warnings from Print warning messages for constructs found in system header files. @@ -2054,6 +2170,7 @@ the warning. @table @gcctabopt @item -W +@opindex W Print extra warning messages for these events: @itemize @bullet @@ -2131,6 +2248,7 @@ struct s x = @{ 3, 4 @}; @end itemize @item -Wfloat-equal +@opindex Wfloat-equal Warn if floating point values are used in equality comparisons. The idea behind this is that sometimes it is convenient (for the @@ -2145,6 +2263,7 @@ this is done with the relational operators, so equality comparisons are probably mistaken. @item -Wtraditional (C only) +@opindex Wtraditional Warn about certain constructs that behave differently in traditional and ISO C. Also warn about ISO C constructs that have no traditional C equivalent, and/or problematic constructs which should be avoided. @@ -2223,37 +2342,45 @@ conversion warnings, for the full set use @samp{-Wconversion}. @end itemize @item -Wundef +@opindex Wundef Warn if an undefined identifier is evaluated in an @samp{#if} directive. @item -Wshadow +@opindex Wshadow Warn whenever a local variable shadows another local variable, parameter or global variable or whenever a built-in function is shadowed. @item -Wlarger-than-@var{len} +@opindex Wlarger-than Warn whenever an object of larger than @var{len} bytes is defined. @item -Wpointer-arith +@opindex Wpointer-arith Warn about anything that depends on the ``size of'' a function type or of @code{void}. GNU C assigns these types a size of 1, for convenience in calculations with @code{void *} pointers and pointers to functions. @item -Wbad-function-cast (C only) +@opindex Wbad-function-cast Warn whenever a function call is cast to a non-matching type. For example, warn if @code{int malloc()} is cast to @code{anything *}. @item -Wcast-qual +@opindex Wcast-qual Warn whenever a pointer is cast so as to remove a type qualifier from the target type. For example, warn if a @code{const char *} is cast to an ordinary @code{char *}. @item -Wcast-align +@opindex Wcast-align Warn whenever a pointer is cast such that the required alignment of the target is increased. For example, warn if a @code{char *} is cast to an @code{int *} on machines where integers can only be accessed at two- or four-byte boundaries. @item -Wwrite-strings +@opindex Wwrite-strings Give string constants the type @code{const char[@var{length}]} so that copying the address of one into a non-@code{const} @code{char *} pointer will get a warning. These warnings will help you find at @@ -2263,6 +2390,7 @@ declarations and prototypes. Otherwise, it will just be a nuisance; this is why we did not make @samp{-Wall} request these warnings. @item -Wconversion +@opindex 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 @@ -2275,6 +2403,7 @@ converted to an unsigned type. For example, warn about the assignment casts like @code{(unsigned) -1}. @item -Wsign-compare +@opindex Wsign-compare @cindex warning for comparison of signed and unsigned values @cindex comparison of signed and unsigned values, warning @cindex signed and unsigned values, comparison warning @@ -2284,29 +2413,34 @@ This warning is also enabled by @samp{-W}; to get the other warnings of @samp{-W} without this warning, use @samp{-W -Wno-sign-compare}. @item -Waggregate-return +@opindex 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.) @item -Wstrict-prototypes (C only) +@opindex 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.) @item -Wmissing-prototypes (C only) +@opindex 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. @item -Wmissing-declarations +@opindex 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. @item -Wmissing-noreturn +@opindex Wmissing-noreturn Warn about functions which might be candidates for attribute @code{noreturn}. Note these are only possible candidates, not absolute ones. Care should be taken to manually verify functions actually do not ever return before @@ -2315,6 +2449,8 @@ bugs could be introduced. You will not get a warning for @code{main} in hosted C environments. @item -Wmissing-format-attribute +@opindex Wmissing-format-attribute +@opindex Wformat If @samp{-Wformat} is enabled, also warn about functions which might be candidates for @code{format} attributes. Note these are only possible candidates, not absolute ones. GCC will guess that @code{format} @@ -2325,6 +2461,7 @@ appropriate may not be detected. This option has no effect unless @samp{-Wformat} is enabled (possibly by @samp{-Wall}). @item -Wpacked +@opindex Wpacked Warn if a structure is given the packed attribute, but the packed attribute has no effect on the layout or size of the structure. Such structures may be mis-aligned for little benefit. For @@ -2346,19 +2483,23 @@ struct bar @{ @end smallexample @item -Wpadded +@opindex Wpadded Warn if padding is included in a structure, either to align an element of the structure or to align the whole structure. Sometimes when this happens it is possible to rearrange the fields of the structure to reduce the padding and so make the structure smaller. @item -Wredundant-decls +@opindex 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. @item -Wnested-externs (C only) +@opindex Wnested-externs Warn if an @code{extern} declaration is encountered within a function. @item -Wunreachable-code +@opindex Wunreachable-code Warn if the compiler detects that code will never be executed. This option is intended to warn when the compiler detects that at @@ -2380,15 +2521,19 @@ because the program does work. Another common use of unreachable code is to provide behaviour which is selectable at compile-time. @item -Winline +@opindex Winline Warn if a function can not be inlined and it was declared as inline. @item -Wlong-long +@opindex Wlong-long +@opindex Wno-long-long Warn if @samp{long long} type is used. This is default. To inhibit the warning messages, use @samp{-Wno-long-long}. Flags @samp{-Wlong-long} and @samp{-Wno-long-long} are taken into account only when @samp{-pedantic} flag is used. @item -Wdisabled-optimization +@opindex Wdisabled-optimization Warn if a requested optimization pass is disabled. This warning does not generally indicate that there is anything wrong with your code; it merely indicates that GCC's optimizers were unable to handle the code @@ -2397,6 +2542,7 @@ complex; GCC will refuse to optimize programs when the optimization itself is likely to take inordinate amounts of time. @item -Werror +@opindex Werror Make all warnings into errors. @end table @@ -2410,6 +2556,7 @@ either your program or GCC: @table @gcctabopt @item -g +@opindex g Produce debugging information in the operating system's native format (stabs, COFF, XCOFF, or DWARF). GDB can work with this debugging information. @@ -2438,12 +2585,14 @@ The following options are useful when GCC is generated with the capability for more than one debugging format. @item -ggdb +@opindex ggdb Produce debugging information for use by GDB. This means to use the most expressive format available (DWARF 2, stabs, or the native format if neither of those are supported), including GDB extensions if at all possible. @item -gstabs +@opindex 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. On MIPS, Alpha and System V Release 4 systems this option @@ -2451,21 +2600,25 @@ produces stabs debugging output which is not understood by DBX or SDB. On System V Release 4 systems this option requires the GNU assembler. @item -gstabs+ +@opindex 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. @item -gcoff +@opindex 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. @item -gxcoff +@opindex 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. @item -gxcoff+ +@opindex 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 @@ -2473,17 +2626,20 @@ refuse to read the program, and may cause assemblers other than the GNU assembler (GAS) to fail with an error. @item -gdwarf +@opindex gdwarf Produce debugging information in DWARF version 1 format (if that is supported). This is the format used by SDB on most System V Release 4 systems. @item -gdwarf+ +@opindex gdwarf+ Produce debugging information in DWARF version 1 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. @item -gdwarf-2 +@opindex gdwarf-2 Produce debugging information in DWARF version 2 format (if that is supported). This is the format used by DBX on IRIX 6. @@ -2508,6 +2664,7 @@ you use @samp{-g3}. @cindex @code{prof} @item -p +@opindex p Generate extra code to write profile information suitable for the analysis program @code{prof}. You must use this option when compiling the source files you want data about, and you must also use it when @@ -2515,6 +2672,7 @@ linking. @cindex @code{gprof} @item -pg +@opindex pg Generate extra code to write profile information suitable for the analysis program @code{gprof}. You must use this option when compiling the source files you want data about, and you must also use it when @@ -2522,6 +2680,7 @@ linking. @cindex @code{tcov} @item -a +@opindex a Generate extra code to write profile information for basic blocks, which will record the number of times each basic block is executed, the basic block start address, and the function name containing the basic block. If @samp{-g} is @@ -2534,18 +2693,22 @@ however, that the format of the data is not what @code{tcov} expects. Eventually GNU @code{gprof} should be extended to process this data. @item -Q +@opindex Q Makes the compiler print out each function name as it is compiled, and print some statistics about each pass when it finishes. @item -ftime-report +@opindex ftime-report Makes the compiler print some statistics about the time consumed by each pass when it finishes. @item -fmem-report +@opindex fmem-report Makes the compiler print some statistics about permanent memory allocation when it finishes. @item -ax +@opindex ax Generate extra code to profile basic blocks. Your executable will produce output that is a superset of that produced when @samp{-a} is used. Additional output is the source and target address of the basic @@ -2619,6 +2782,7 @@ written to @file{bbtrace.gz}. It is solely used for counting jump frequencies. @item -fprofile-arcs +@opindex fprofile-arcs Instrument @dfn{arcs} during compilation. For each function of your program, GCC creates a program flow graph, then finds a spanning tree for the graph. Only arcs that are not on the spanning tree have to be @@ -2649,6 +2813,7 @@ branch probabilities. @need 2000 @item -ftest-coverage +@opindex ftest-coverage Create data files for the @code{gcov} code-coverage utility (@pxref{Gcov,, @code{gcov}: a GCC Test Coverage Program}). The data file names begin with the name of your source file: @@ -2667,6 +2832,7 @@ block and arc execution counts from the information in the @end table @item -d@var{letters} +@opindex d Says to make debugging dumps during compilation at times specified by @var{letters}. This is used for debugging the compiler. The file names for most of the dumps are made by appending a pass number and a word to @@ -2675,98 +2841,137 @@ Here are the possible letters for use in @var{letters}, and their meanings: @table @samp @item A +@opindex dA Annotate the assembler output with miscellaneous debugging information. @item b +@opindex db Dump after computing branch probabilities, to @file{@var{file}.11.bp}. @item B +@opindex dB Dump after block reordering, to @file{@var{file}.26.bbro}. @item c +@opindex dc Dump after instruction combination, to the file @file{@var{file}.14.combine}. @item C +@opindex dC Dump after the first if conversion, to the file @file{@var{file}.15.ce}. @item d +@opindex dd Dump after delayed branch scheduling, to @file{@var{file}.29.dbr}. @item D +@opindex dD Dump all macro definitions, at the end of preprocessing, in addition to normal output. @item e +@opindex de Dump after SSA optimizations, to @file{@var{file}.05.ssa} and @file{@var{file}.06.ussa}. @item E +@opindex dE Dump after the second if conversion, to @file{@var{file}.24.ce2}. @item f +@opindex df Dump after life analysis, to @file{@var{file}.13.life}. @item F +@opindex dF Dump after purging @code{ADDRESSOF} codes, to @file{@var{file}.04.addressof}. @item g +@opindex dg Dump after global register allocation, to @file{@var{file}.19.greg}. @item o +@opindex do Dump after post-reload CSE and other optimizations, to @file{@var{file}.20.postreload}. @item G +@opindex dG Dump after GCSE, to @file{@var{file}.08.gcse}. @item i +@opindex di Dump after sibling call optimizations, to @file{@var{file}.01.sibling}. @item j +@opindex dj Dump after the first jump optimization, to @file{@var{file}.02.jump}. @item J +@opindex dJ Dump after the last jump optimization, to @file{@var{file}.27.jump2}. @item k +@opindex dk Dump after conversion from registers to stack, to @file{@var{file}.29.stack}. @item l +@opindex dl Dump after local register allocation, to @file{@var{file}.18.lreg}. @item L +@opindex dL Dump after loop optimization, to @file{@var{file}.09.loop}. @item M +@opindex dM Dump after performing the machine dependent reorganisation pass, to @file{@var{file}.28.mach}. @item n +@opindex dn Dump after register renumbering, to @file{@var{file}.23.rnreg}. @item N +@opindex dN Dump after the register move pass, to @file{@var{file}.16.regmove}. @item r +@opindex dr Dump after RTL generation, to @file{@var{file}.00.rtl}. @item R +@opindex dR Dump after the second instruction scheduling pass, to @file{@var{file}.25.sched2}. @item s +@opindex ds Dump after CSE (including the jump optimization that sometimes follows CSE), to @file{@var{file}.03.cse}. @item S +@opindex dS Dump after the first instruction scheduling pass, to @file{@var{file}.17.sched}. @item t +@opindex dt Dump after the second CSE pass (including the jump optimization that sometimes follows CSE), to @file{@var{file}.10.cse2}. @item w +@opindex dw Dump after the second flow pass, to @file{@var{file}.21.flow2}. @item X +@opindex dX Dump after dead code elimination, to @file{@var{file}.06.dce}. @item z +@opindex dz Dump after the peephole pass, to @file{@var{file}.22.peephole2}. @item a +@opindex da Produce all the dumps listed above. @item m +@opindex dm Print statistics on memory usage, at the end of the run, to standard error. @item p +@opindex dp Annotate the assembler output with a comment indicating which pattern and alternative was used. The length of each instruction is also printed. @item P +@opindex dP Dump the RTL in the assembler output as a comment before each instruction. Also turns on @samp{-dp} annotation. @item v +@opindex dv For each of the other indicated dump files (except for @file{@var{file}.00.rtl}), dump a representation of the control flow graph suitable for viewing with VCG to @file{@var{file}.@var{pass}.vcg}. @item x +@opindex dx Just generate RTL for a function instead of compiling it. Usually used with @samp{r}. @item y +@opindex dy Dump debugging information during parsing, to standard error. @end table @item -fdump-unnumbered +@opindex fdump-unnumbered When doing debugging dumps (see -d option above), suppress instruction numbers and line number note output. This makes it more feasible to use diff on debugging dumps for compiler invocations with different @@ -2774,6 +2979,7 @@ options, in particular with and without -g. @item -fdump-translation-unit (C and C++ only) @item -fdump-translation-unit-@var{number} (C and C++ only) +@opindex fdump-translation-unit Dump a representation of the tree structure for the entire translation unit to a file. The file name is made by appending @file{.tu} to the source file name. If the -@var{number} form is used, @var{number} @@ -2781,6 +2987,7 @@ controls the details of the dump as described for the -fdump-tree options. @item -fdump-class-hierarchy (C++ only) @item -fdump-class-hierarchy-@var{number} (C++ only) +@opindex fdump-class-hierarchy Dump a representation of each class's hierarchy and virtual function table layout to a file. The file name is made by appending @file{.class} to the source file name. If the -@var{number} form is used, @var{number} @@ -2789,6 +2996,7 @@ options. @item -fdump-ast-@var{switch} (C++ only) @item -fdump-ast-@var{switch}-@var{number} (C++ only) +@opindex fdump-ast Control the dumping at various stages of processing the abstract syntax tree to a file. The file name is generated by appending a switch specific suffix to the source file name. If the -@var{number} form is @@ -2814,6 +3022,7 @@ Dump after all tree based optimization, to @file{@var{file}.optimized}. @end table @item -fpretend-float +@opindex 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 @@ -2821,6 +3030,7 @@ sequence will probably be the same as GCC would make when running on the target machine. @item -save-temps +@opindex save-temps Store the usual ``temporary'' intermediate files permanently; place them in the current directory and name them based on the source file. Thus, compiling @file{foo.c} with @samp{-c -save-temps} would produce files @@ -2829,6 +3039,7 @@ preprocessed @file{foo.i} output file even though the compiler now normally uses an integrated preprocessor. @item -time +@opindex time Report the CPU time taken by each subprocess in the compilation sequence. For C source files, this is the compiler proper and assembler (plus the linker if linking is done). The output looks like this: @@ -2844,15 +3055,18 @@ time spent executing operating system routines on behalf of the program. Both numbers are in seconds. @item -print-file-name=@var{library} +@opindex print-file-name Print the full absolute name of the library file @var{library} that would be used when linking---and don't do anything else. With this option, GCC does not compile or link anything; it just prints the file name. @item -print-prog-name=@var{program} +@opindex print-prog-name Like @samp{-print-file-name}, but searches for a program such as @samp{cpp}. @item -print-libgcc-file-name +@opindex print-libgcc-file-name Same as @samp{-print-file-name=libgcc.a}. This is useful when you use @samp{-nostdlib} or @samp{-nodefaultlibs} @@ -2863,6 +3077,7 @@ gcc -nostdlib @var{files}@dots{} `gcc -print-libgcc-file-name` @end example @item -print-search-dirs +@opindex print-search-dirs Print the name of the configured installation directory and a list of program and library directories gcc will search---and don't do anything else. @@ -2875,14 +3090,17 @@ Don't forget the trailing '/'. @xref{Environment Variables}. @item -dumpmachine +@opindex dumpmachine Print the compiler's target machine (for example, @samp{i686-pc-linux-gnu})---and don't do anything else. @item -dumpversion +@opindex dumpversion Print the compiler version (for example, @samp{3.0})---and don't do anything else. @item -dumpspecs +@opindex dumpspecs Print the compiler's built-in specs---and don't do anything else. (This is used when GCC itself is being built.) @xref{Spec Files}. @end table @@ -2897,6 +3115,8 @@ These options control various sorts of optimizations: @table @gcctabopt @item -O @itemx -O1 +@opindex O +@opindex O1 Optimize. Optimizing compilation takes somewhat more time, and a lot more memory for a large function. @@ -2922,6 +3142,7 @@ without a frame pointer. On some machines the compiler also turns on other flags.@refill @item -O2 +@opindex O2 Optimize even more. GCC performs nearly all supported optimizations that do not involve a space-speed tradeoff. The compiler does not perform loop unrolling or function inlining when you specify @samp{-O2}. @@ -2934,14 +3155,17 @@ function inlining, and register renaming. It also turns on the on machines where doing so does not interfere with debugging. @item -O3 +@opindex O3 Optimize yet more. @samp{-O3} turns on all optimizations specified by @samp{-O2} and also turns on the @samp{-finline-functions} and @samp{-frename-registers} options. @item -O0 +@opindex O0 Do not optimize. @item -Os +@opindex Os Optimize for size. @samp{-Os} enables all @samp{-O2} optimizations that do not typically increase code size. It also performs further optimizations designed to reduce code size. @@ -2959,6 +3183,7 @@ adding it. @table @gcctabopt @item -ffloat-store +@opindex ffloat-store Do not store floating point variables in registers, and inhibit other options that might change whether a floating point value is taken from a register or memory. @@ -2973,6 +3198,7 @@ point. Use @samp{-ffloat-store} for such programs, after modifying them to store all pertinent intermediate computations into variables. @item -fno-default-inline +@opindex fno-default-inline Do not make member functions inline by default merely because they are defined inside the class scope (C++ only). Otherwise, when you specify @w{@samp{-O}}, member functions defined inside class scope are compiled @@ -2980,12 +3206,14 @@ inline by default; i.e., you don't need to add @samp{inline} in front of the member function name. @item -fno-defer-pop +@opindex 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. @item -fforce-mem +@opindex fforce-mem Force memory operands to be copied into registers before doing arithmetic on them. This produces better code by making all memory references potential common subexpressions. When they are not common @@ -2993,11 +3221,13 @@ subexpressions, instruction combination should eliminate the separate register-load. The @samp{-O2} option turns on this option. @item -fforce-addr +@opindex fforce-addr Force memory address constants to be copied into registers before doing arithmetic on them. This may produce better code just as @samp{-fforce-mem} may. @item -fomit-frame-pointer +@opindex 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 @@ -3021,18 +3251,22 @@ Usage, gcc.info, Using and Porting GCC}.@refill @end ifclear @item -foptimize-sibling-calls +@opindex foptimize-sibling-calls Optimize sibling and tail recursive calls. @item -ftrapv +@opindex ftrapv This option generates traps for signed overflow on addition, subtraction, multiplication operations. @item -fno-inline +@opindex fno-inline Don't pay attention to the @code{inline} keyword. Normally this option is used to keep the compiler from expanding any functions inline. Note that if you are not optimizing, no functions can be expanded inline. @item -finline-functions +@opindex 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. @@ -3042,6 +3276,7 @@ declared @code{static}, then the function is normally not output as assembler code in its own right. @item -finline-limit=@var{n} +@opindex finline-limit By default, gcc limits the size of functions that can be inlined. This flag allows the control of this limit for functions that are explicitly marked as inline (ie marked with the inline keyword or defined within the class @@ -3059,12 +3294,14 @@ of assembly instructions and as such its exact meaning might change from one release to an another. @item -fkeep-inline-functions +@opindex fkeep-inline-functions Even if all calls to a given function are integrated, and the function is declared @code{static}, nevertheless output a separate run-time callable version of the function. This switch does not affect @code{extern inline} functions. @item -fkeep-static-consts +@opindex fkeep-static-consts Emit variables declared @code{static const} when optimization isn't turned on, even if the variables aren't referenced. @@ -3073,6 +3310,7 @@ check if the variable was referenced, regardless of whether or not optimization is turned on, use the @samp{-fno-keep-static-consts} option. @item -fno-function-cse +@opindex fno-function-cse Do not put function addresses in registers; make each instruction that calls a constant function contain the function's address explicitly. @@ -3081,6 +3319,7 @@ that alter the assembler output may be confused by the optimizations performed when this option is not used. @item -ffast-math +@opindex ffast-math Sets @samp{-fno-math-errno}, @samp{-funsafe-math-optimizations}, and @samp{-fno-trapping-math}. @@ -3092,6 +3331,7 @@ an exact implementation of IEEE or ISO rules/specifications for math functions. @item -fno-math-errno +@opindex fno-math-errno Do not set ERRNO after calling math functions that are executed with a single instruction, e.g., sqrt. A program that relies on IEEE exceptions for math error handling may want to use this flag @@ -3106,6 +3346,7 @@ The default is @samp{-fmath-errno}. The @samp{-ffast-math} option sets @samp{-fno-math-errno}. @item -funsafe-math-optimizations +@opindex funsafe-math-optimizations Allow optimizations for floating-point arithmetic that (a) assume that arguments and results are valid and (b) may violate IEEE or ANSI standards. @@ -3119,6 +3360,7 @@ The default is @samp{-fno-unsafe-math-optimizations}. The @samp{-ffast-math} option sets @samp{-funsafe-math-optimizations}. @item -fno-trapping-math +@opindex fno-trapping-math Compile code assuming that floating-point operations cannot generate user-visible traps. Setting this option may allow faster code if one relies on ``non-stop'' IEEE arithmetic, for example. @@ -3145,10 +3387,12 @@ of optimizations to be performed is desired. @table @gcctabopt @item -fstrength-reduce +@opindex fstrength-reduce Perform the optimizations of loop strength reduction and elimination of iteration variables. @item -fthread-jumps +@opindex 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 @@ -3156,6 +3400,7 @@ second branch or a point immediately following it, depending on whether the condition is known to be true or false. @item -fcse-follow-jumps +@opindex 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 @code{if} statement with an @@ -3163,6 +3408,7 @@ example, when CSE encounters an @code{if} statement with an tested is false. @item -fcse-skip-blocks +@opindex fcse-skip-blocks This is similar to @samp{-fcse-follow-jumps}, but causes CSE to follow jumps which conditionally skip over blocks. When CSE encounters a simple @code{if} statement with no else clause, @@ -3170,29 +3416,35 @@ encounters a simple @code{if} statement with no else clause, body of the @code{if}. @item -frerun-cse-after-loop +@opindex frerun-cse-after-loop Re-run common subexpression elimination after loop optimizations has been performed. @item -frerun-loop-opt +@opindex frerun-loop-opt Run the loop optimizer twice. @item -fgcse +@opindex fgcse Perform a global common subexpression elimination pass. This pass also performs global constant and copy propagation. @item -fgcse-lm +@opindex fgcse-lm When -fgcse-lm is enabled, global common subexpression elimination will attempt to move loads which are only killed by stores into themselves. This allows a loop containing a load/store sequence to be changed to a load outside the loop, and a copy/store within the loop. @item -fgcse-sm +@opindex fgcse-sm When -fgcse-sm is enabled, A store motion pass is run after global common subexpression elimination. This pass will attempt to move stores out of loops. When used in conjunction with -fgcse-lm, loops containing a load/store sequence can be changed to a load before the loop and a store after the loop. @item -fdelete-null-pointer-checks +@opindex fdelete-null-pointer-checks Use global dataflow analysis to identify and eliminate useless null pointer checks. Programs which rely on NULL pointer dereferences @emph{not} halting the program may not work properly with this option. Use @@ -3200,10 +3452,13 @@ halting the program may not work properly with this option. Use which depend on that behavior. @item -fexpensive-optimizations +@opindex fexpensive-optimizations Perform a number of minor optimizations that are relatively expensive. @item -foptimize-register-move @itemx -fregmove +@opindex foptimize-register-move +@opindex fregmove Attempt to reassign register numbers in move instructions and as operands of other simple instructions in order to maximize the amount of register tying. This is especially helpful on machines with two-operand @@ -3214,11 +3469,13 @@ Note @option{-fregmove} and @option{-foptimize-register-move} are the same optimization. @item -fdelayed-branch +@opindex fdelayed-branch If supported for the target machine, attempt to reorder instructions to exploit instruction slots available after delayed branch instructions. @item -fschedule-insns +@opindex 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 @@ -3226,6 +3483,7 @@ by allowing other instructions to be issued until the result of the load or floating point instruction is required. @item -fschedule-insns2 +@opindex fschedule-insns2 Similar to @samp{-fschedule-insns}, 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 @@ -3233,6 +3491,8 @@ registers and where memory load instructions take more than one cycle. @item -ffunction-sections @itemx -fdata-sections +@opindex ffunction-sections +@opindex fdata-sections Place each function or data item into its own section in the output file if the target supports arbitrary sections. The name of the function or the name of the data item determines the section's name @@ -3252,6 +3512,7 @@ specify this option and you may have problems with debugging if you specify both this option and @samp{-g}. @item -fcaller-saves +@opindex 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 @@ -3264,21 +3525,25 @@ For all machines, optimization level 2 and higher enables this flag by default. @item -funroll-loops +@opindex 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. @samp{-funroll-loops} implies both @samp{-fstrength-reduce} and @samp{-frerun-cse-after-loop}. @item -funroll-all-loops +@opindex funroll-all-loops Perform the optimization of loop unrolling. This is done for all loops and usually makes programs run more slowly. @samp{-funroll-all-loops} implies @samp{-fstrength-reduce} as well as @samp{-frerun-cse-after-loop}. @item -fmove-all-movables +@opindex fmove-all-movables Forces all invariant computations in loops to be moved outside the loop. @item -freduce-all-givs +@opindex freduce-all-givs Forces all general-induction variables in loops to be strength-reduced. @@ -3300,9 +3565,11 @@ We're very interested in code that runs @emph{slower} when these options are @emph{enabled}. @item -fno-peephole +@opindex fno-peephole Disable any machine-specific peephole optimizations. @item -fbranch-probabilities +@opindex fbranch-probabilities After running a program compiled with @samp{-fprofile-arcs} (@pxref{Debugging Options,, Options for Debugging Your Program or @command{gcc}}), you can compile it a second time using @@ -3320,6 +3587,7 @@ exactly determine which path is taken more often. @end ifset @item -fno-guess-branch-probability +@opindex fno-guess-branch-probability Sometimes gcc will opt to guess branch probabilities when none are available from either profile directed feedback (@samp{-fprofile-arcs}) or @samp{__builtin_expect}. In a hard real-time system, people don't @@ -3329,6 +3597,7 @@ switch allows users to reduce non-determinism, possibly at the expense of inferior optimization. @item -fstrict-aliasing +@opindex fstrict-aliasing Allows the compiler to assume the strictest aliasing rules applicable to the language being compiled. For C (and C++), this activates optimizations based on the type of expressions. In particular, an @@ -3376,6 +3645,7 @@ allowed to alias. For an example, see the C front-end function @item -falign-functions @itemx -falign-functions=@var{n} +@opindex falign-functions Align the start of functions to the next power-of-two greater than @var{n}, skipping up to @var{n} bytes. For instance, @samp{-falign-functions=32} aligns functions to the next 32-byte @@ -3392,6 +3662,7 @@ If @var{n} is not specified, use a machine-dependent default. @item -falign-labels @itemx -falign-labels=@var{n} +@opindex falign-labels Align all branch targets to a power-of-two boundary, skipping up to @var{n} bytes like @samp{-falign-functions}. This option can easily make code slower, because it must insert dummy operations for when the @@ -3405,6 +3676,7 @@ very likely to be @samp{1}, meaning no alignment. @item -falign-loops @itemx -falign-loops=@var{n} +@opindex falign-loops Align loops to a power-of-two boundary, skipping up to @var{n} bytes like @samp{-falign-functions}. The hope is that the loop will be executed many times, which will make up for any execution of the dummy @@ -3414,6 +3686,7 @@ If @var{n} is not specified, use a machine-dependent default. @item -falign-jumps @itemx -falign-jumps=@var{n} +@opindex falign-jumps Align branch targets to a power-of-two boundary, for branch targets where the targets can only be reached by jumping, skipping up to @var{n} bytes like @samp{-falign-functions}. In this case, no dummy operations @@ -3422,20 +3695,24 @@ need be executed. If @var{n} is not specified, use a machine-dependent default. @item -fssa +@opindex fssa Perform optimizations in static single assignment form. Each function's flow graph is translated into SSA form, optimizations are performed, and the flow graph is translated back from SSA form. Users should not specify this option, since it is not yet ready for production use. @item -fdce +@opindex fdce Perform dead-code elimination in SSA form. Requires @samp{-fssa}. Like @samp{-fssa}, this is an experimental feature. @item -fsingle-precision-constant +@opindex fsingle-precision-constant Treat floating point constant as single precision constant instead of implicitly converting it to double precision constant. @item -frename-registers +@opindex frename-registers Attempt to avoid false dependancies in scheduled code by making use of registers left over after register allocation. This optimization will most benefit processors with lots of registers. It can, however, @@ -3443,6 +3720,7 @@ make debugging impossible, since variables will no longer stay in a ``home register''. @item --param @var{name}=@var{value} +@opindex param In some places, GCC uses various constants to control the amount of optimization that is done. For example, GCC will not inline functions that contain more that a certain number of instructions. You can @@ -3498,6 +3776,7 @@ compilation. @table @gcctabopt @item -include @var{file} +@opindex include Process @var{file} as input before processing the regular input file. In effect, the contents of @var{file} are compiled first. Any @samp{-D} and @samp{-U} options on the command line are always processed before @@ -3506,6 +3785,7 @@ written. All the @samp{-include} and @samp{-imacros} options are processed in the order in which they are written. @item -imacros @var{file} +@opindex imacros Process @var{file} as input, discarding the resulting output, before processing the regular input file. Because the output generated from @var{file} is discarded, the only effect of @samp{-imacros @var{file}} @@ -3514,6 +3794,7 @@ main input. All the @samp{-include} and @samp{-imacros} options are processed in the order in which they are written. @item -idirafter @var{dir} +@opindex idirafter @cindex second include path Add the directory @var{dir} to the second include path. The directories on the second include path are searched when a header file is not found @@ -3521,10 +3802,12 @@ in any of the directories in the main include path (the one that @samp{-I} adds to). @item -iprefix @var{prefix} +@opindex iprefix Specify @var{prefix} as the prefix for subsequent @samp{-iwithprefix} options. @item -iwithprefix @var{dir} +@opindex iwithprefix Add a directory to the second include path. The directory's name is made by concatenating @var{prefix} and @var{dir}, where @var{prefix} was specified previously with @samp{-iprefix}. If you have not specified a @@ -3532,16 +3815,19 @@ prefix yet, the directory containing the installed passes of the compiler is used as the default. @item -iwithprefixbefore @var{dir} +@opindex iwithprefixbefore Add a directory to the main include path. The directory's name is made by concatenating @var{prefix} and @var{dir}, as in the case of @samp{-iwithprefix}. @item -isystem @var{dir} +@opindex isystem Add a directory to the beginning of the second include path, marking it as a system directory, so that it gets the same special treatment as is applied to the standard system directories. @item -nostdinc +@opindex nostdinc Do not search the standard system directories for header files. Only the directories you have specified with @samp{-I} options (and the current directory, if appropriate) are searched. @xref{Directory @@ -3551,7 +3837,7 @@ By using both @samp{-nostdinc} and @samp{-I-}, you can limit the include-file search path to only those directories you specify explicitly. @item -remap -@findex -remap +@opindex remap When searching for a header file in a directory, remap file names if a file named @file{header.gcc} exists in that directory. This can be used to work around limitations of file systems with file name restrictions. @@ -3560,25 +3846,29 @@ tokens on each line: the first token is the name to map, and the second token is the actual name to use. @item -undef +@opindex undef Do not predefine any nonstandard macros. (Including architecture flags). @item -E +@opindex 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. @item -C +@opindex C Tell the preprocessor not to discard comments. Used with the @samp{-E} option. @item -P +@opindex P Tell the preprocessor not to generate @samp{#line} directives. Used with the @samp{-E} option. @cindex make @cindex dependencies, make @item -M -@findex -M +@opindex M Instead of outputting the result of preprocessing, output a rule suitable for @code{make} describing the dependencies of the main source file. The preprocessor outputs one @code{make} rule containing the @@ -3591,13 +3881,13 @@ rule is split into several lines using @samp{\}-newline. @samp{-M} implies @samp{-E}. @item -MM -@findex -MM +@opindex MM Like @samp{-M}, but mention only the files included with @samp{#include "@var{file}"}. System header files included with @samp{#include <@var{file}>} are omitted. @item -MD -@findex -MD +@opindex MD Like @samp{-M} but the dependency information is written to a file rather than stdout. @code{gcc} will use the same file name and directory as the object file, but with the suffix ".d" instead. @@ -3611,12 +3901,12 @@ dependency files into a single dependency file suitable for using with the @samp{make} command. @item -MMD -@findex -MMD +@opindex MMD Like @samp{-MD} except mention only user header files, not system -header files. @item -MF @var{file} -@findex -MF +@opindex MF When used with @samp{-M} or @samp{-MM}, specifies a file to write the dependencies to. This allows the preprocessor to write the preprocessed file to stdout normally. If no @samp{-MF} switch is given, CPP sends @@ -3627,7 +3917,7 @@ the environment variable @env{DEPENDENCIES_OUTPUT} (@pxref{Environment Variables}). @item -MG -@findex -MG +@opindex MG When used with @samp{-M} or @samp{-MM}, @samp{-MG} says to treat missing header files as generated files and assume they live in the same directory as the source file. It suppresses preprocessed output, as a @@ -3636,7 +3926,7 @@ missing header file is ordinarily an error. This feature is used in automatic updating of makefiles. @item -MP -@findex -MP +@opindex MP This option instructs CPP to add a phony target for each dependency other than the main file, causing each to depend on nothing. These dummy rules work around errors @code{make} gives if you remove header @@ -3652,8 +3942,8 @@ This is typical output:- @item -MQ @var{target} @item -MT @var{target} -@findex -MQ -@findex -MT +@opindex MQ +@opindex MT By default CPP uses the main file name, including any path, and appends the object suffix, normally ``.o'', to it to obtain the name of the target for dependency generation. With @samp{-MT} you can specify a @@ -3681,16 +3971,19 @@ The default target is automatically quoted, as if it were given with @samp{-MQ}. @item -H +@opindex H Print the name of each header file used, in addition to other normal activities. @item -A@var{question}(@var{answer}) +@opindex A Assert the answer @var{answer} for @var{question}, in case it is tested with a preprocessing conditional such as @samp{#if #@var{question}(@var{answer})}. @samp{-A-} disables the standard assertions that normally describe the target machine. @item -D@var{macro} +@opindex D Define macro @var{macro} with the string @samp{1} as its definition. @item -D@var{macro}=@var{defn} @@ -3702,6 +3995,7 @@ order, and always before @samp{-imacros @var{file}}, regardless of the order in which they are written. @item -U@var{macro} +@opindex U Undefine macro @var{macro}. @samp{-U} options are evaluated after all @samp{-D} options, but before any @samp{-include} and @samp{-imacros} options. @@ -3711,25 +4005,28 @@ order, and always before @samp{-imacros @var{file}}, regardless of the order in which they are written. @item -dM +@opindex 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 @samp{-E} option. @item -dD +@opindex dD Tell the preprocessing to pass all macro definitions into the output, in their proper sequence in the rest of the output. @item -dN +@opindex dN Like @samp{-dD} except that the macro arguments and contents are omitted. Only @samp{#define @var{name}} is included in the output. @item -dI -@findex -dI +@opindex dI Output @samp{#include} directives in addition to the result of preprocessing. @item -trigraphs -@findex -trigraphs +@opindex trigraphs Process ISO standard trigraph sequences. These are three-character sequences, all starting with @samp{??}, that are defined by ISO C to stand for single characters. For example, @samp{??/} stands for @@ -3773,6 +4070,7 @@ properly. Portable code should not rely on trigraphs being either converted or ignored. @item -Wp\,@var{option} +@opindex Wp Pass @var{option} as an option to the preprocessor. If @var{option} contains commas, it is split into multiple options at the commas. @end table @@ -3785,6 +4083,7 @@ You can pass options to the assembler. @table @gcctabopt @item -Wa\,@var{option} +@opindex Wa Pass @var{option} as an option to the assembler. If @var{option} contains commas, it is split into multiple options at the commas. @end table @@ -3810,6 +4109,9 @@ to the linker. @item -c @itemx -S @itemx -E +@opindex c +@opindex S +@opindex E If any of these options is used, then the linker is not run, and object file names should not be used as arguments. @xref{Overall Options}. @@ -3817,6 +4119,7 @@ Options}. @cindex Libraries @item -l@var{library} @itemx -l @var{library} +@opindex l Search the library named @var{library} when linking. (The second alternative with the library as a separate argument is only for POSIX compliance and is not recommended.) @@ -3844,15 +4147,18 @@ is that @samp{-l} surrounds @var{library} with @samp{lib} and @samp{.a} and searches several directories. @item -lobjc +@opindex lobjc You need this special case of the @samp{-l} option in order to link an Objective C program. @item -nostartfiles +@opindex nostartfiles Do not use the standard system startup files when linking. The standard system libraries are used normally, unless @option{-nostdlib} or @option{-nodefaultlibs} is used. @item -nodefaultlibs +@opindex nodefaultlibs Do not use the standard system libraries when linking. Only the libraries you specify will be passed to the linker. The standard startup files are used normally, unless @option{-nostartfiles} @@ -3863,6 +4169,7 @@ libc. These entry points should be supplied through some other mechanism when this option is specified. @item -nostdlib +@opindex nostdlib Do not use the standard system startup files or libraries when linking. No startup files and only the libraries you specify will be passed to the linker. The compiler may generate calls to memcmp, memset, and memcpy @@ -3897,13 +4204,16 @@ library subroutines. (For example, @samp{__main}, used to ensure C++ constructors will be called; @pxref{Collect2,,@command{collect2}}.) @item -s +@opindex s Remove all symbol table and relocation information from the executable. @item -static +@opindex static On systems that support dynamic linking, this prevents linking with the shared libraries. On other systems, this option has no effect. @item -shared +@opindex shared Produce a shared object which can then be linked with other objects to form an executable. Not all systems support this option. For predictable results, you must also specify the same set of options that were used to @@ -3917,6 +4227,8 @@ is innocuous.} @item -shared-libgcc @itemx -static-libgcc +@opindex shared-libgcc +@opindex static-libgcc On systems that provide @file{libgcc} as a shared library, these options force the use of either the shared or static version respectively. If no shared version of @file{libgcc} was built when the compiler was @@ -3940,12 +4252,14 @@ explicitly say @samp{-shared-libgcc} if you want to use the shared @file{libgcc}. @item -symbolic +@opindex symbolic Bind references to global symbols when building a shared object. Warn about any unresolved references (unless overridden by the link editor option @samp{-Xlinker -z -Xlinker defs}). Only a few systems support this option. @item -Xlinker @var{option} +@opindex Xlinker Pass @var{option} as an option to the linker. You can use this to supply system-specific linker options which GCC does not know how to recognize. @@ -3958,10 +4272,12 @@ For example, to pass @samp{-assert definitions}, you must write string as a single argument, which is not what the linker expects. @item -Wl\,@var{option} +@opindex Wl Pass @var{option} as an option to the linker. If @var{option} contains commas, it is split into multiple options at the commas. @item -u @var{symbol} +@opindex u Pretend the symbol @var{symbol} is undefined, to force linking of library modules to define it. You can use @samp{-u} multiple times with different symbols to force loading of additional library modules. @@ -3978,6 +4294,7 @@ libraries and for parts of the compiler: @table @gcctabopt @item -I@var{dir} +@opindex I Add the directory @var{dir} to the head of the list of directories to be searched for header files. This can be used to override a system header file, substituting your own version, since these directories are @@ -3988,6 +4305,7 @@ one @samp{-I} option, the directories are scanned in left-to-right order; the standard system directories come after. @item -I- +@opindex I- Any directories you specify with @samp{-I} options before the @samp{-I-} option are searched only for the case of @samp{#include "@var{file}"}; they are not searched for @samp{#include <@var{file}>}. @@ -4010,10 +4328,12 @@ for header files. Thus, @samp{-I-} and @samp{-nostdinc} are independent. @item -L@var{dir} +@opindex L Add directory @var{dir} to the list of directories to be searched for @samp{-l}. @item -B@var{prefix} +@opindex B This option specifies where to find the executables, libraries, include files, and data files of the compiler itself. @@ -4047,6 +4367,7 @@ the environment variable @env{GCC_EXEC_PREFIX}. @xref{Environment Variables}. @item -specs=@var{file} +@opindex specs Process @var{file} after the compiler reads in the standard @file{specs} file, in order to override the defaults that the @file{gcc} driver program uses when determining what switches to pass to @file{cc1}, @@ -4540,6 +4861,7 @@ you may sometimes wish to use another. @table @gcctabopt @item -b @var{machine} +@opindex b The argument @var{machine} specifies the target machine for compilation. This is useful when you have installed GCC as a cross-compiler. @@ -4553,6 +4875,7 @@ When you do not specify @samp{-b}, it normally means to compile for the same type of machine that you are using. @item -V @var{version} +@opindex V The argument @var{version} specifies which version of GCC to run. This is useful when multiple versions are installed. For example, @var{version} might be @samp{2.0}, meaning to run GCC version 2.0. @@ -4677,6 +5000,8 @@ given below. @table @gcctabopt @item -m68000 @itemx -mc68000 +@opindex m68000 +@opindex mc68000 Generate output for a 68000. This is the default when the compiler is configured for 68000-based systems. @@ -4685,19 +5010,24 @@ including the 68008, 68302, 68306, 68307, 68322, 68328 and 68356. @item -m68020 @itemx -mc68020 +@opindex m68020 +@opindex mc68020 Generate output for a 68020. This is the default when the compiler is configured for 68020-based systems. @item -m68881 +@opindex m68881 Generate output containing 68881 instructions for floating point. This is the default for most 68020 systems unless @samp{-nfp} was specified when the compiler was configured. @item -m68030 +@opindex m68030 Generate output for a 68030. This is the default when the compiler is configured for 68030-based systems. @item -m68040 +@opindex m68040 Generate output for a 68040. This is the default when the compiler is configured for 68040-based systems. @@ -4706,6 +5036,7 @@ emulated by software on the 68040. Use this option if your 68040 does not have code to emulate those instructions. @item -m68060 +@opindex m68060 Generate output for a 68060. This is the default when the compiler is configured for 68060-based systems. @@ -4714,6 +5045,7 @@ have to be emulated by software on the 68060. Use this option if your 68060 does not have code to emulate those instructions. @item -mcpu32 +@opindex mcpu32 Generate output for a CPU32. This is the default when the compiler is configured for CPU32-based systems. @@ -4722,6 +5054,7 @@ CPU32 or CPU32+ core, including the 68330, 68331, 68332, 68333, 68334, 68336, 68340, 68341, 68349 and 68360. @item -m5200 +@opindex m5200 Generate output for a 520X "coldfire" family cpu. This is the default when the compiler is configured for 520X-based systems. @@ -4730,21 +5063,25 @@ the MCF5202, MCF5203, MCF5204 and MCF5202. @item -m68020-40 +@opindex 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. The generated code does use the 68881 instructions that are emulated on the 68040. @item -m68020-60 +@opindex m68020-60 Generate output for a 68060, 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. The generated code does use the 68881 instructions that are emulated on the 68060. @item -mfpa +@opindex mfpa Generate output containing Sun FPA instructions for floating point. @item -msoft-float +@opindex msoft-float Generate output containing library calls for floating point. @strong{Warning:} the requisite libraries are not available for all m68k targets. Normally the facilities of the machine's usual C compiler are @@ -4754,18 +5091,22 @@ cross-compilation. The embedded targets @samp{m68k-*-aout} and @samp{m68k-*-coff} do provide software floating point support. @item -mshort +@opindex mshort Consider type @code{int} to be 16 bits wide, like @code{short int}. @item -mnobitfield +@opindex mnobitfield Do not use the bit-field instructions. The @samp{-m68000}, @samp{-mcpu32} and @samp{-m5200} options imply @w{@samp{-mnobitfield}}. @item -mbitfield +@opindex mbitfield Do use the bit-field instructions. The @samp{-m68020} option implies @samp{-mbitfield}. This is the default if you use a configuration designed for a 68020. @item -mrtd +@opindex mrtd Use a different function-calling convention, in which functions that take a fixed number of arguments return with the @code{rtd} instruction, which pops their arguments while returning. This @@ -4790,6 +5131,8 @@ The @code{rtd} instruction is supported by the 68010, 68020, 68030, @item -malign-int @itemx -mno-align-int +@opindex malign-int +@opindex mno-align-int Control whether GCC aligns @code{int}, @code{long}, @code{long long}, @code{float}, @code{double}, and @code{long double} variables on a 32-bit boundary (@samp{-malign-int}) or a 16-bit boundary (@samp{-mno-align-int}). @@ -4801,6 +5144,7 @@ align structures containing the above types differently than most published application binary interface specifications for the m68k. @item -mpcrel +@opindex mpcrel Use the pc-relative addressing mode of the 68000 directly, instead of using a global offset table. At present, this option implies -fpic, allowing at most a 16-bit offset for pc-relative addressing. -fPIC is @@ -4809,7 +5153,8 @@ not presently supported with -mpcrel, though this could be supported for @item -mno-strict-align @itemx -mstrict-align -@kindex -mstrict-align +@opindex mno-strict-align +@opindex mstrict-align Do not (do) assume that unaligned memory references will be handled by the system. @@ -4827,22 +5172,29 @@ the defaults for the most common choices are given below. @table @gcctabopt @item -m6811 @itemx -m68hc11 +@opindex m6811 +@opindex m68hc11 Generate output for a 68HC11. This is the default when the compiler is configured for 68HC11-based systems. @item -m6812 @itemx -m68hc12 +@opindex m6812 +@opindex m68hc12 Generate output for a 68HC12. This is the default when the compiler is configured for 68HC12-based systems. @item -mauto-incdec +@opindex mauto-incdec Enable the use of 68HC12 pre and post auto-increment and auto-decrement addressing modes. @item -mshort +@opindex mshort Consider type @code{int} to be 16 bits wide, like @code{short int}. @item -msoft-reg-count=@var{count} +@opindex msoft-reg-count Specify the number of pseudo-soft registers which are used for the code generation. The maximum number is 32. Using more pseudo-soft register may or may not result in better code depending on the program. @@ -4858,15 +5210,18 @@ These @samp{-m} options are defined for the Vax: @table @gcctabopt @item -munix +@opindex munix Do not output certain jump instructions (@code{aobleq} and so on) that the Unix assembler for the Vax cannot handle across long ranges. @item -mgnu +@opindex mgnu Do output those jump instructions, on the assumption that you will assemble with the GNU assembler. @item -mg +@opindex mg Output code for g-format floating point numbers instead of d-format. @end table @@ -4879,6 +5234,8 @@ These @samp{-m} switches are supported on the SPARC: @table @gcctabopt @item -mno-app-regs @itemx -mapp-regs +@opindex mno-app-regs +@opindex mapp-regs Specify @samp{-mapp-regs} to generate output using the global registers 2 through 4, which the SPARC SVR4 ABI reserves for applications. This is the default. @@ -4889,11 +5246,15 @@ software with this option. @item -mfpu @itemx -mhard-float +@opindex mfpu +@opindex mhard-float Generate output containing floating point instructions. This is the default. @item -mno-fpu @itemx -msoft-float +@opindex mno-fpu +@opindex msoft-float Generate output containing library calls for floating point. @strong{Warning:} the requisite libraries are not available for all SPARC targets. Normally the facilities of the machine's usual C compiler are @@ -4909,10 +5270,12 @@ library that comes with GCC, with @samp{-msoft-float} in order for this to work. @item -mhard-quad-float +@opindex mhard-quad-float Generate output containing quad-word (long double) floating point instructions. @item -msoft-quad-float +@opindex msoft-quad-float Generate output containing library calls for quad-word (long double) floating point instructions. The functions called are those specified in the SPARC ABI. This is the default. @@ -4926,6 +5289,8 @@ this is much slower than calling the ABI library routines. Thus the @item -mno-epilogue @itemx -mepilogue +@opindex mno-epilogue +@opindex mepilogue With @samp{-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 @@ -4936,6 +5301,8 @@ at every function exit. @item -mno-flat @itemx -mflat +@opindex mno-flat +@opindex mflat With @samp{-mflat}, the compiler does not generate save/restore instructions and will use a "flat" or single register window calling convention. This model uses %i7 as the frame pointer and is compatible with the normal @@ -4948,6 +5315,8 @@ instructions (except for leaf functions) and is the normal mode of operation. @item -mno-unaligned-doubles @itemx -munaligned-doubles +@opindex mno-unaligned-doubles +@opindex munaligned-doubles Assume that doubles have 8 byte alignment. This is the default. With @samp{-munaligned-doubles}, GCC assumes that doubles have 8 byte @@ -4959,6 +5328,8 @@ in a performance loss, especially for floating point code. @item -mno-faster-structs @itemx -mfaster-structs +@opindex mno-faster-structs +@opindex mfaster-structs With @samp{-mfaster-structs}, the compiler assumes that structures should have 8 byte alignment. This enables the use of pairs of @code{ldd} and @code{std} instructions for copies in structure @@ -4970,6 +5341,8 @@ the rules of the ABI. @item -mv8 @itemx -msparclite +@opindex mv8 +@opindex msparclite These two options select variations on the SPARC architecture. By default (unless specifically configured for the Fujitsu SPARClite), @@ -4988,6 +5361,8 @@ They have been replaced with @samp{-mcpu=xxx}. @item -mcypress @itemx -msupersparc +@opindex mcypress +@opindex msupersparc These two options select the processor for which the code is optimised. With @samp{-mcypress} (the default), the compiler optimizes code for the @@ -5002,6 +5377,7 @@ These options are deprecated and will be deleted in a future GCC release. They have been replaced with @samp{-mcpu=xxx}. @item -mcpu=@var{cpu_type} +@opindex mcpu Set the instruction set, register set, and instruction scheduling parameters for machine type @var{cpu_type}. Supported values for @var{cpu_type} are @samp{v7}, @samp{cypress}, @samp{v8}, @samp{supersparc}, @samp{sparclite}, @@ -5024,6 +5400,7 @@ implementations. @end smallexample @item -mtune=@var{cpu_type} +@opindex mtune Set the instruction scheduling parameters for machine type @var{cpu_type}, but do not set the instruction set or register set that the option @samp{-mcpu=}@var{cpu_type} would. @@ -5041,14 +5418,17 @@ on the SPARCLET processor. @table @gcctabopt @item -mlittle-endian +@opindex mlittle-endian Generate code for a processor running in little-endian mode. @item -mlive-g0 +@opindex mlive-g0 Treat register @code{%g0} as a normal register. GCC will continue to clobber it as necessary but will not assume it always reads as 0. @item -mbroken-saverestore +@opindex mbroken-saverestore Generate code that does not use non-trivial forms of the @code{save} and @code{restore} instructions. Early versions of the SPARCLET processor do not correctly handle @code{save} and @code{restore} instructions used with @@ -5064,33 +5444,40 @@ on SPARC V9 processors in 64-bit environments. @table @gcctabopt @item -mlittle-endian +@opindex mlittle-endian Generate code for a processor running in little-endian mode. @item -m32 @itemx -m64 +@opindex m32 +@opindex m64 Generate code for a 32-bit or 64-bit environment. The 32-bit environment sets int, long and pointer to 32 bits. The 64-bit environment sets int to 32 bits and long and pointer to 64 bits. @item -mcmodel=medlow +@opindex mcmodel=medlow Generate code for the Medium/Low code model: the program must be linked in the low 32 bits of the address space. Pointers are 64 bits. Programs can be statically or dynamically linked. @item -mcmodel=medmid +@opindex mcmodel=medmid Generate code for the Medium/Middle code model: the program must be linked in the low 44 bits of the address space, the text segment must be less than 2G bytes, and data segment must be within 2G of the text segment. Pointers are 64 bits. @item -mcmodel=medany +@opindex mcmodel=medany Generate code for the Medium/Anywhere code model: the program may be linked anywhere in the address space, the text segment must be less than 2G bytes, and data segment must be within 2G of the text segment. Pointers are 64 bits. @item -mcmodel=embmedany +@opindex mcmodel=embmedany Generate code for the Medium/Anywhere code model for embedded systems: assume a 32-bit text and a 32-bit data segment, both starting anywhere (determined at link time). Register %g4 points to the base of the @@ -5099,6 +5486,8 @@ Programs are statically linked, PIC is not supported. @item -mstack-bias @itemx -mno-stack-bias +@opindex mstack-bias +@opindex mno-stack-bias With @samp{-mstack-bias}, GCC assumes that the stack pointer, and frame pointer if present, are offset by -2047 which must be added back when making stack frame references. @@ -5113,51 +5502,62 @@ These @samp{-m} options are defined for Convex: @table @gcctabopt @item -mc1 +@opindex mc1 Generate output for C1. The code will run on any Convex machine. The preprocessor symbol @code{__convex__c1__} is defined. @item -mc2 +@opindex mc2 Generate output for C2. Uses instructions not available on C1. Scheduling and other optimizations are chosen for max performance on C2. The preprocessor symbol @code{__convex_c2__} is defined. @item -mc32 +@opindex mc32 Generate output for C32xx. Uses instructions not available on C1. Scheduling and other optimizations are chosen for max performance on C32. The preprocessor symbol @code{__convex_c32__} is defined. @item -mc34 +@opindex mc34 Generate output for C34xx. Uses instructions not available on C1. Scheduling and other optimizations are chosen for max performance on C34. The preprocessor symbol @code{__convex_c34__} is defined. @item -mc38 +@opindex mc38 Generate output for C38xx. Uses instructions not available on C1. Scheduling and other optimizations are chosen for max performance on C38. The preprocessor symbol @code{__convex_c38__} is defined. @item -margcount +@opindex margcount Generate code which puts an argument count in the word preceding each argument list. This is compatible with regular CC, and a few programs may need the argument count word. GDB and other source-level debuggers do not need it; this info is in the symbol table. @item -mnoargcount +@opindex mnoargcount Omit the argument count word. This is the default. @item -mvolatile-cache +@opindex mvolatile-cache Allow volatile references to be cached. This is the default. @item -mvolatile-nocache +@opindex mvolatile-nocache Volatile references bypass the data cache, going all the way to memory. This is only needed for multi-processor code that does not use standard synchronization instructions. Making non-volatile references to volatile locations will not necessarily work. @item -mlong32 +@opindex mlong32 Type long is 32 bits, the same as type int. This is the default. @item -mlong64 +@opindex mlong64 Type long is 64 bits, the same as type long long. This option is useless, because no library support exists for it. @end table @@ -5170,29 +5570,29 @@ These @samp{-m} options are defined for the AMD Am29000: @table @gcctabopt @item -mdw -@kindex -mdw +@opindex mdw @cindex DW bit (29k) Generate code that assumes the @code{DW} bit is set, i.e., that byte and halfword operations are directly supported by the hardware. This is the default. @item -mndw -@kindex -mndw +@opindex mndw Generate code that assumes the @code{DW} bit is not set. @item -mbw -@kindex -mbw +@opindex mbw @cindex byte writes (29k) Generate code that assumes the system supports byte and halfword write operations. This is the default. @item -mnbw -@kindex -mnbw +@opindex mnbw Generate code that assumes the systems does not support byte and halfword write operations. @samp{-mnbw} implies @samp{-mndw}. @item -msmall -@kindex -msmall +@opindex msmall @cindex memory model (29k) 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 @@ -5200,27 +5600,28 @@ than 256k. This allows the @code{call} instruction to be used instead of a @code{const}, @code{consth}, @code{calli} sequence. @item -mnormal -@kindex -mnormal +@opindex mnormal Use the normal memory model: Generate @code{call} instructions only when calling functions in the same file and @code{calli} instructions otherwise. This works if each file occupies less than 256 KB but allows the entire executable to be larger than 256 KB. This is the default. @item -mlarge +@opindex mlarge Always use @code{calli} instructions. Specify this option if you expect a single file to compile into more than 256 KB of code. @item -m29050 -@kindex -m29050 +@opindex m29050 @cindex processor selection (29k) Generate code for the Am29050. @item -m29000 -@kindex -m29000 +@opindex m29000 Generate code for the Am29000. This is the default. @item -mkernel-registers -@kindex -mkernel-registers +@opindex mkernel-registers @cindex kernel and user registers (29k) Generate references to registers @code{gr64-gr95} instead of to registers @code{gr96-gr127}. This option can be used when compiling @@ -5231,20 +5632,22 @@ Note that when this option is used, register names in @samp{-f} flags must use the normal, user-mode, names. @item -muser-registers -@kindex -muser-registers +@opindex muser-registers Use the normal set of global registers, @code{gr96-gr127}. This is the default. @item -mstack-check @itemx -mno-stack-check -@kindex -mstack-check +@opindex mstack-check +@opindex mno-stack-check @cindex stack checks (29k) Insert (or do not insert) a call to @code{__msp_check} after each stack adjustment. This is often used for kernel code. @item -mstorem-bug @itemx -mno-storem-bug -@kindex -mstorem-bug +@opindex mstorem-bug +@opindex mno-storem-bug @cindex storem bug (29k) @samp{-mstorem-bug} handles 29k processors which cannot handle the separation of a mtsrim insn and a storem instruction (most 29000 chips @@ -5252,19 +5655,21 @@ to date, but not the 29050). @item -mno-reuse-arg-regs @itemx -mreuse-arg-regs -@kindex -mreuse-arg-regs +@opindex mno-reuse-arg-regs +@opindex mreuse-arg-regs @samp{-mno-reuse-arg-regs} tells the compiler to only use incoming argument registers for copying out arguments. This helps detect calling a function with fewer arguments than it was declared with. @item -mno-impure-text @itemx -mimpure-text -@kindex -mimpure-text +@opindex mno-impure-text +@opindex mimpure-text @samp{-mimpure-text}, used in addition to @samp{-shared}, tells the compiler to not pass @samp{-assert pure-text} to the linker when linking a shared object. @item -msoft-float -@kindex -msoft-float +@opindex msoft-float Generate output containing library calls for floating point. @strong{Warning:} the requisite libraries are not part of GCC. Normally the facilities of the machine's usual C compiler are used, but @@ -5273,7 +5678,7 @@ own arrangements to provide suitable library functions for cross-compilation. @item -mno-multm -@kindex -mno-multm +@opindex mno-multm Do not generate multm or multmu instructions. This is useful for some embedded systems which do not have trap handlers for these instructions. @end table @@ -5287,7 +5692,7 @@ architectures: @table @gcctabopt @item -mapcs-frame -@kindex -mapcs-frame +@opindex mapcs-frame Generate a stack frame that is compliant with the ARM Procedure Call Standard for all functions, even if this is not strictly necessary for correct execution of the code. Specifying @samp{-fomit-frame-pointer} @@ -5295,18 +5700,18 @@ with this option will cause the stack frames not to be generated for leaf functions. The default is @samp{-mno-apcs-frame}. @item -mapcs -@kindex -mapcs +@opindex mapcs This is a synonym for @samp{-mapcs-frame}. @item -mapcs-26 -@kindex -mapcs-26 +@opindex mapcs-26 Generate code for a processor running with a 26-bit program counter, and conforming to the function calling standards for the APCS 26-bit option. This option replaces the @samp{-m2} and @samp{-m3} options of previous releases of the compiler. @item -mapcs-32 -@kindex -mapcs-32 +@opindex mapcs-32 Generate code for a processor running with a 32-bit program counter, and conforming to the function calling standards for the APCS 32-bit option. This option replaces the @samp{-m6} option of previous releases @@ -5315,8 +5720,7 @@ of the compiler. @ignore @c not currently implemented @item -mapcs-stack-check -@kindex -mapcs-stack-check -@kindex -mno-apcs-stack-check +@opindex mapcs-stack-check Generate code to check the amount of stack space available upon entry to every function (that actually uses some stack space). If there is insufficient space available then either the function @@ -5327,8 +5731,7 @@ system is required to provide these functions. The default is @c not currently implemented @item -mapcs-float -@kindex -mapcs-float -@kindex -mno-apcs-float +@opindex mapcs-float Pass floating point arguments using the float point registers. This is one of the variants of the APCS. This option is recommended if the target hardware has a floating point unit or if a lot of floating point @@ -5338,15 +5741,13 @@ size if @samp{-mapcs-float} is used. @c not currently implemented @item -mapcs-reentrant -@kindex -mapcs-reentrant -@kindex -mno-apcs-reentrant +@opindex mapcs-reentrant Generate reentrant, position independent code. The default is @samp{-mno-apcs-reentrant}. @end ignore @item -mthumb-interwork -@kindex -mthumb-interwork -@kindex -mno-thumb-interwork +@opindex mthumb-interwork Generate code which supports calling between the ARM and Thumb instruction sets. Without this option the two instruction sets cannot be reliably used inside one program. The default is @@ -5354,8 +5755,7 @@ be reliably used inside one program. The default is when @samp{-mthumb-interwork} is specified. @item -mno-sched-prolog -@kindex -mno-sched-prolog -@kindex -msched-prolog +@opindex mno-sched-prolog Prevent the reordering of instructions in the function prolog, or the merging of those instruction with the instructions in the function's body. This means that all functions will start with a recognizable set @@ -5365,10 +5765,12 @@ locate the start if functions inside an executable piece of code. The default is @samp{-msched-prolog}. @item -mhard-float +@opindex mhard-float Generate output containing floating point instructions. This is the default. @item -msoft-float +@opindex msoft-float Generate output containing library calls for floating point. @strong{Warning:} the requisite libraries are not available for all ARM targets. Normally the facilities of the machine's usual C compiler are @@ -5383,14 +5785,17 @@ library that comes with GCC, with @samp{-msoft-float} in order for this to work. @item -mlittle-endian +@opindex mlittle-endian Generate code for a processor running in little-endian mode. This is the default for all standard configurations. @item -mbig-endian +@opindex mbig-endian Generate code for a processor running in big-endian mode; the default is to compile code for a little-endian processor. @item -mwords-little-endian +@opindex mwords-little-endian This option only applies when generating code for big-endian processors. Generate code for a little-endian word order but a big-endian byte order. That is, a byte order of the form @samp{32107654}. Note: this @@ -5399,7 +5804,7 @@ big-endian ARM processors generated by versions of the compiler prior to 2.8. @item -malignment-traps -@kindex -malignment-traps +@opindex malignment-traps Generate code that will not trap if the MMU has alignment traps enabled. On ARM architectures prior to ARMv4, there were no instructions to access half-word objects stored in memory. However, when reading from @@ -5416,7 +5821,7 @@ since these processors have instructions to directly access half-word objects in memory. @item -mno-alignment-traps -@kindex -mno-alignment-traps +@opindex mno-alignment-traps Generate code that assumes that the MMU will not trap unaligned accesses. This produces better code when the target instruction set does not have half-word memory operations (i.e. implementations prior to @@ -5432,28 +5837,28 @@ instructions available. @item -mshort-load-bytes @itemx -mno-short-load-words -@kindex -mshort-load-bytes -@kindex -mno-short-load-words +@opindex mshort-load-bytes +@opindex mno-short-load-words These are deprecated aliases for @samp{-malignment-traps}. @item -mno-short-load-bytes @itemx -mshort-load-words -@kindex -mno-short-load-bytes -@kindex -mshort-load-words +@opindex mno-short-load-bytes +@opindex mshort-load-words This are deprecated aliases for @samp{-mno-alignment-traps}. @item -mbsd -@kindex -mbsd +@opindex mbsd This option only applies to RISC iX. Emulate the native BSD-mode compiler. This is the default if @samp{-ansi} is not specified. @item -mxopen -@kindex -mxopen +@opindex mxopen This option only applies to RISC iX. Emulate the native X/Open-mode compiler. @item -mno-symrename -@kindex -mno-symrename +@opindex mno-symrename This option only applies to RISC iX. Do not run the assembler post-processor, @samp{symrename}, after code has been assembled. Normally it is necessary to modify some of the standard symbols in @@ -5461,8 +5866,8 @@ preparation for linking with the RISC iX C library; this option suppresses this pass. The post-processor is never run when the compiler is built for cross-compilation. -@item -mcpu=<name> -@kindex -mcpu= +@item -mcpu=@var{name} +@opindex mcpu This specifies the name of the target ARM processor. GCC uses this name to determine what kind of instructions it can emit when generating assembly code. Permissible names are: arm2, arm250, arm3, arm6, arm60, @@ -5472,8 +5877,8 @@ arm7tdmi, arm8, strongarm, strongarm110, strongarm1100, arm8, arm810, arm9, arm9e, arm920, arm920t, arm940t, arm9tdmi, arm10tdmi, arm1020t, xscale. -@itemx -mtune=<name> -@kindex -mtune= +@itemx -mtune=@var{name} +@opindex mtune This option is very similar to the @samp{-mcpu=} option, except that instead of specifying the actual target processor type, and hence restricting which instructions can be used, it specifies that GCC should @@ -5483,24 +5888,24 @@ will generate based on the cpu specified by a @samp{-mcpu=} option. For some ARM implementations better performance can be obtained by using this option. -@item -march=<name> -@kindex -march= +@item -march=@var{name} +@opindex march This specifies the name of the target ARM architecture. GCC uses this name to determine what kind of instructions it can emit when generating assembly code. This option can be used in conjunction with or instead of the @samp{-mcpu=} option. Permissible names are: armv2, armv2a, armv3, armv3m, armv4, armv4t, armv5, armv5t, armv5te. -@item -mfpe=<number> -@itemx -mfp=<number> -@kindex -mfpe= -@kindex -mfp= +@item -mfpe=@var{number} +@itemx -mfp=@var{number} +@opindex mfpe +@opindex mfp This specifies the version of the floating point emulation available on the target. Permissible values are 2 and 3. @samp{-mfp=} is a synonym for @samp{-mfpe=}, for compatibility with older versions of GCC. -@item -mstructure-size-boundary=<n> -@kindex -mstructure-size-boundary +@item -mstructure-size-boundary=@var{n} +@opindex mstructure-size-boundary The size of all structures and unions will be rounded up to a multiple of the number of bits set by this option. Permissible values are 8 and 32. The default value varies for different toolchains. For the COFF @@ -5512,14 +5917,15 @@ libraries compiled with the other value, if they exchange information using structures or unions. @item -mabort-on-noreturn -@kindex -mabort-on-noreturn -@kindex -mnoabort-on-noreturn +@opindex mabort-on-noreturn Generate a call to the function @code{abort} at the end of a @code{noreturn} function. It will be executed if the function tries to return. @item -mlong-calls @itemx -mno-long-calls +@opindex mlong-calls +@opindex mno-long-calls Tells the compiler to perform function calls by first loading the address of the function into a register and then performing a subroutine call on this register. This switch is needed if the target function @@ -5545,23 +5951,23 @@ the compiler generates code to handle function calls via function pointers. @item -mnop-fun-dllimport -@kindex -mnop-fun-dllimport +@opindex mnop-fun-dllimport Disable support for the @emph{dllimport} attribute. @item -msingle-pic-base -@kindex -msingle-pic-base +@opindex msingle-pic-base Treat the register used for PIC addressing as read-only, rather than loading it in the prologue for each function. The run-time system is responsible for initialising this register with an appropriate value before execution begins. -@item -mpic-register=<reg> -@kindex -mpic-register= +@item -mpic-register=@var{reg} +@opindex mpic-register Specify the register to be used for PIC addressing. The default is R10 unless stack-checking is enabled, when R9 is used. @item -mpoke-function-name -@kindex -mpoke-function-name +@opindex mpoke-function-name Write the name of each function into the text section, directly preceding the function prologue. The generated code is similar to this: @@ -5584,33 +5990,31 @@ there is a function name embedded immediately preceding this location and has length @code{((pc[-3]) & 0xff000000)}. @item -mthumb -@kindex -mthumb +@opindex mthumb Generate code for the 16-bit Thumb instruction set. The default is to use the 32-bit ARM instruction set. @item -mtpcs-frame -@kindex -mtpcs-frame -@kindex -mno-tpcs-frame +@opindex mtpcs-frame Generate a stack frame that is compliant with the Thumb Procedure Call Standard for all non-leaf functions. (A leaf function is one that does not call any other functions.) The default is @samp{-mno-tpcs-frame}. @item -mtpcs-leaf-frame -@kindex -mtpcs-leaf-frame -@kindex -mno-tpcs-leaf-frame +@opindex mtpcs-leaf-frame Generate a stack frame that is compliant with the Thumb Procedure Call Standard for all leaf functions. (A leaf function is one that does not call any other functions.) The default is @samp{-mno-apcs-leaf-frame}. @item -mcallee-super-interworking -@kindex -mcallee-super-interworking +@opindex mcallee-super-interworking Gives all externally visible functions in the file being compiled an ARM instruction set header which switches to Thumb mode before executing the rest of the function. This allows these functions to be called from non-interworking code. @item -mcaller-super-interworking -@kindex -mcaller-super-interworking +@opindex mcaller-super-interworking Allows calls via function pointers (including virtual functions) to execute correctly regardless of whether the target code has been compiled for interworking or not. There is a small overhead in the cost @@ -5625,6 +6029,7 @@ These @samp{-m} options are defined for Matsushita MN10200 architectures: @table @gcctabopt @item -mrelax +@opindex mrelax Indicate to the linker that it should perform a relaxation optimization pass to shorten branches, calls and absolute memory addresses. This option only has an effect when used on the command line for the final link step. @@ -5639,21 +6044,26 @@ These @samp{-m} options are defined for Matsushita MN10300 architectures: @table @gcctabopt @item -mmult-bug +@opindex mmult-bug Generate code to avoid bugs in the multiply instructions for the MN10300 processors. This is the default. @item -mno-mult-bug +@opindex mno-mult-bug Do not generate code to avoid bugs in the multiply instructions for the MN10300 processors. @item -mam33 +@opindex mam33 Generate code which uses features specific to the AM33 processor. @item -mno-am33 +@opindex mno-am33 Do not generate code which uses features specific to the AM33 processor. This is the default. @item -mrelax +@opindex mrelax Indicate to the linker that it should perform a relaxation optimization pass to shorten branches, calls and absolute memory addresses. This option only has an effect when used on the command line for the final link step. @@ -5670,6 +6080,7 @@ These @samp{-m} options are defined for Mitsubishi M32R/D architectures: @table @gcctabopt @item -mcode-model=small +@opindex mcode-model=small Assume all objects live in the lower 16MB of memory (so that their addresses can be loaded with the @code{ld24} instruction), and assume all subroutines are reachable with the @code{bl} instruction. @@ -5679,11 +6090,13 @@ The addressability of a particular object can be set with the @code{model} attribute. @item -mcode-model=medium +@opindex mcode-model=medium Assume objects may be anywhere in the 32-bit address space (the compiler will generate @code{seth/add3} instructions to load their addresses), and assume all subroutines are reachable with the @code{bl} instruction. @item -mcode-model=large +@opindex mcode-model=large Assume objects may be anywhere in the 32-bit address space (the compiler will generate @code{seth/add3} instructions to load their addresses), and assume subroutines may not be reachable with the @code{bl} instruction @@ -5691,6 +6104,7 @@ assume subroutines may not be reachable with the @code{bl} instruction instruction sequence). @item -msdata=none +@opindex msdata=none Disable use of the small data area. Variables will be put into one of @samp{.data}, @samp{bss}, or @samp{.rodata} (unless the @code{section} attribute has been specified). @@ -5701,14 +6115,17 @@ Objects may be explicitly put in the small data area with the @code{section} attribute using one of these sections. @item -msdata=sdata +@opindex msdata=sdata Put small global and static data in the small data area, but do not generate special code to reference them. @item -msdata=use +@opindex msdata=use Put small global and static data in the small data area, and generate special instructions to reference them. @item -G @var{num} +@opindex G @cindex smaller data references Put global and static objects less than or equal to @var{num} bytes into the small data or bss sections instead of the normal data or bss @@ -5731,35 +6148,34 @@ These @samp{-m} options are defined for Motorola 88k architectures: @table @gcctabopt @item -m88000 -@kindex -m88000 +@opindex m88000 Generate code that works well on both the m88100 and the m88110. @item -m88100 -@kindex -m88100 +@opindex m88100 Generate code that works best for the m88100, but that also runs on the m88110. @item -m88110 -@kindex -m88110 +@opindex m88110 Generate code that works best for the m88110, and may not run on the m88100. @item -mbig-pic -@kindex -mbig-pic +@opindex mbig-pic Obsolete option to be removed from the next revision. Use @samp{-fPIC}. @item -midentify-revision -@kindex -midentify-revision -@kindex ident +@opindex midentify-revision @cindex identifying source, compiler (88k) Include an @code{ident} directive in the assembler output recording the source file name, compiler name and version, timestamp, and compilation flags used. @item -mno-underscores -@kindex -mno-underscores +@opindex mno-underscores @cindex underscores, avoiding (88k) In assembler output, emit symbol names without adding an underscore character at the beginning of each name. The default is to use an @@ -5767,8 +6183,8 @@ underscore as prefix on each name. @item -mocs-debug-info @itemx -mno-ocs-debug-info -@kindex -mocs-debug-info -@kindex -mno-ocs-debug-info +@opindex mocs-debug-info +@opindex mno-ocs-debug-info @cindex OCS (88k) @cindex debugging, 88k OCS Include (or omit) additional debugging information (about registers used @@ -5779,7 +6195,7 @@ Delta 88 SVr3.2 is to include this information; other 88k configurations omit this information by default. @item -mocs-frame-position -@kindex -mocs-frame-position +@opindex mocs-frame-position @cindex register positions in frame (88k) When emitting COFF debugging information for automatic variables and parameters stored on the stack, use the offset from the canonical frame @@ -5789,7 +6205,7 @@ function. The DG/UX, SVr4, Delta88 SVr3.2, and BCS configurations use @samp{-mno-ocs-frame-position}. @item -mno-ocs-frame-position -@kindex -mno-ocs-frame-position +@opindex mno-ocs-frame-position @cindex register positions in frame (88k) When emitting COFF debugging information for automatic variables and parameters stored on the stack, use the offset from the frame pointer @@ -5799,8 +6215,8 @@ pointer is not eliminated when debugging information is selected by the @item -moptimize-arg-area @itemx -mno-optimize-arg-area -@kindex -moptimize-arg-area -@kindex -mno-optimize-arg-area +@opindex moptimize-arg-area +@opindex mno-optimize-arg-area @cindex arguments in frame (88k) Control how function arguments are stored in stack frames. @samp{-moptimize-arg-area} saves space by optimizing them, but this @@ -5809,7 +6225,7 @@ conflicts with the 88open specifications. The opposite alternative, GCC does not optimize the argument area. @item -mshort-data-@var{num} -@kindex -mshort-data-@var{num} +@opindex mshort-data @cindex smaller data references (88k) @cindex r0-relative references (88k) Generate smaller data references by making them relative to @code{r0}, @@ -5822,9 +6238,9 @@ involving displacements of less than 512 bytes. than 64k. @item -mserialize-volatile -@kindex -mserialize-volatile +@opindex mserialize-volatile @itemx -mno-serialize-volatile -@kindex -mno-serialize-volatile +@opindex mno-serialize-volatile @cindex sequential consistency on 88k Do, or don't, generate code to guarantee sequential consistency of volatile memory references. By default, consistency is @@ -5852,8 +6268,8 @@ forgo this guarantee, you may use @samp{-mno-serialize-volatile}. @item -msvr4 @itemx -msvr3 -@kindex -msvr4 -@kindex -msvr3 +@opindex msvr4 +@opindex msvr3 @cindex assembler syntax, 88k @cindex SVr4 Turn on (@samp{-msvr4}) or off (@samp{-msvr3}) compiler extensions @@ -5875,14 +6291,14 @@ m88k-dg-dgux m88k configurations. @samp{-msvr3} is the default for all other m88k configurations. @item -mversion-03.00 -@kindex -mversion-03.00 +@opindex mversion-03.00 This option is obsolete, and is ignored. @c ??? which asm syntax better for GAS? option there too? @item -mno-check-zero-division @itemx -mcheck-zero-division -@kindex -mno-check-zero-division -@kindex -mcheck-zero-division +@opindex mno-check-zero-division +@opindex mcheck-zero-division @cindex zero division on 88k Do, or don't, generate code to guarantee that integer division by zero will be detected. By default, detection is guaranteed. @@ -5902,7 +6318,7 @@ specified, both @samp{-mcheck-zero-division} and zero-valued divisors are generated. @item -muse-div-instruction -@kindex -muse-div-instruction +@opindex muse-div-instruction @cindex divide instruction, 88k Use the div instruction for signed integer division on the MC88100 processor. By default, the div instruction is not used. @@ -5932,8 +6348,8 @@ particular, the behavior of such a division with and without @item -mtrap-large-shift @itemx -mhandle-large-shift -@kindex -mtrap-large-shift -@kindex -mhandle-large-shift +@opindex mtrap-large-shift +@opindex mhandle-large-shift @cindex bit shift overflow (88k) @cindex large bit shifts (88k) Include code to detect bit-shifts of more than 31 bits; respectively, @@ -5941,7 +6357,7 @@ trap such shifts or emit code to handle them properly. By default GCC makes no special provision for large bit shifts. @item -mwarn-passed-structs -@kindex -mwarn-passed-structs +@opindex mwarn-passed-structs @cindex structure passing (88k) Warn when a function passes a struct as an argument or result. Structure-passing conventions have changed during the evolution of the C @@ -5968,12 +6384,18 @@ These @samp{-m} options are defined for the IBM RS/6000 and PowerPC: @itemx -mno-powerpc-gfxopt @itemx -mpowerpc64 @itemx -mno-powerpc64 -@kindex -mpower -@kindex -mpower2 -@kindex -mpowerpc -@kindex -mpowerpc-gpopt -@kindex -mpowerpc-gfxopt -@kindex -mpowerpc64 +@opindex mpower +@opindex mno-power +@opindex mpower2 +@opindex mno-power2 +@opindex mpowerpc +@opindex mno-powerpc +@opindex mpowerpc-gpopt +@opindex mno-powerpc-gpopt +@opindex mpowerpc-gfxopt +@opindex mno-powerpc-gfxopt +@opindex mpowerpc64 +@opindex mno-powerpc64 GCC supports two related instruction set architectures for the RS/6000 and PowerPC. The @dfn{POWER} instruction set are those instructions supported by the @samp{rios} chip set used in the original @@ -6021,8 +6443,8 @@ allow use of the MQ register; specify this for the Motorola MPC601. @item -mnew-mnemonics @itemx -mold-mnemonics -@kindex -mnew-mnemonics -@kindex -mold-mnemonics +@opindex mnew-mnemonics +@opindex mold-mnemonics Select which mnemonics to use in the generated assembler code. @samp{-mnew-mnemonics} requests output that uses the assembler mnemonics defined for the PowerPC architecture, while @samp{-mold-mnemonics} @@ -6038,7 +6460,7 @@ should normally not specify either @samp{-mnew-mnemonics} or @samp{-mold-mnemonics}, but should instead accept the default. @item -mcpu=@var{cpu_type} -@kindex -mcpu +@opindex mcpu Set architecture type, register usage, choice of mnemonics, and instruction scheduling parameters for machine type @var{cpu_type}. Supported values for @var{cpu_type} are @samp{rios}, @samp{rios1}, @@ -6086,6 +6508,7 @@ Specifying @samp{-mcpu=403}, @samp{-mcpu=821}, or @samp{-mcpu=860} also enables the @samp{-msoft-float} option. @item -mtune=@var{cpu_type} +@opindex mtune Set the instruction scheduling parameters for machine type @var{cpu_type}, but do not set the architecture type, register usage, choice of mnemonics like @samp{-mcpu=}@var{cpu_type} would. The same @@ -6098,7 +6521,10 @@ instruction scheduling parameters. @itemx -mno-fp-in-toc @itemx -mno-sum-in-toc @itemx -mminimal-toc -@kindex -mminimal-toc +@opindex mfull-toc +@opindex mno-fp-in-toc +@opindex mno-sum-in-toc +@opindex mminimal-toc Modify generation of the TOC (Table Of Contents), which is created for every executable file. The @samp{-mfull-toc} option is selected by default. In that case, GCC will allocate at least one TOC entry for @@ -6125,8 +6551,8 @@ only on files that contain less frequently executed code. @refill @item -maix64 @itemx -maix32 -@kindex -maix64 -@kindex -maix32 +@opindex maix64 +@opindex maix32 Enable 64-bit AIX ABI and calling convention: 64-bit pointers, 64-bit @code{long} type, and the infrastructure needed to support them. Specifying @samp{-maix64} implies @samp{-mpowerpc64} and @@ -6135,7 +6561,8 @@ implies @samp{-mno-powerpc64}. GCC defaults to @samp{-maix32}. @item -mxl-call @itemx -mno-xl-call -@kindex -mxl-call +@opindex mxl-call +@opindex mno-xl-call On AIX, pass floating-point arguments to prototyped functions beyond the register save area (RSA) on the stack in addition to argument FPRs. The AIX calling convention was extended but not initially documented to @@ -6149,13 +6576,13 @@ default and only is necessary when calling subroutines compiled by AIX XL compilers without optimization. @item -mthreads -@kindex -mthreads +@opindex mthreads Support @dfn{AIX Threads}. Link an application written to use @dfn{pthreads} with special libraries and startup code to enable the application to run. @item -mpe -@kindex -mpe +@opindex mpe Support @dfn{IBM RS/6000 SP} @dfn{Parallel Environment} (PE). Link an application written to use message passing with special startup code to enable the application to run. The system must have PE installed in the @@ -6167,13 +6594,16 @@ option are incompatible. @item -msoft-float @itemx -mhard-float -@kindex -msoft-float +@opindex msoft-float +@opindex mhard-float Generate code that does not use (uses) the floating-point register set. Software floating point emulation is provided if you use the @samp{-msoft-float} option, and pass the option to GCC when linking. @item -mmultiple @itemx -mno-multiple +@opindex mmultiple +@opindex mno-multiple Generate code that uses (does not use) the load multiple word instructions and the store multiple word instructions. These instructions are generated by default on POWER systems, and not @@ -6184,7 +6614,8 @@ PPC750 which permit the instructions usage in little endian mode. @item -mstring @itemx -mno-string -@kindex -mstring +@opindex mstring +@opindex mno-string Generate code that uses (does not use) the load string instructions and the store string word instructions to save multiple registers and do small block moves. These instructions are generated by default on @@ -6196,7 +6627,8 @@ usage in little endian mode. @item -mupdate @itemx -mno-update -@kindex -mupdate +@opindex mupdate +@opindex mno-update Generate code that uses (does not use) the load or store instructions that update the base register to the address of the calculated memory location. These instructions are generated by default. If you use @@ -6207,14 +6639,16 @@ signals may get corrupted data. @item -mfused-madd @itemx -mno-fused-madd -@kindex -mfused-madd +@opindex mfused-madd +@opindex mno-fused-madd Generate code that uses (does not use) the floating point multiply and accumulate instructions. These instructions are generated by default if hardware floating is used. @item -mno-bit-align @itemx -mbit-align -@kindex -mbit-align +@opindex mno-bit-align +@opindex mbit-align On System V.4 and embedded PowerPC systems do not (do) force structures and unions that contain bit fields to be aligned to the base type of the bit field. @@ -6227,13 +6661,15 @@ size. @item -mno-strict-align @itemx -mstrict-align -@kindex -mstrict-align +@opindex mno-strict-align +@opindex mstrict-align On System V.4 and embedded PowerPC systems do not (do) assume that unaligned memory references will be handled by the system. @item -mrelocatable @itemx -mno-relocatable -@kindex -mrelocatable +@opindex mrelocatable +@opindex mno-relocatable On embedded PowerPC systems generate code that allows (does not allow) the program to be relocated to a different address at runtime. If you use @samp{-mrelocatable} on any module, all objects linked together must @@ -6241,6 +6677,8 @@ be compiled with @samp{-mrelocatable} or @samp{-mrelocatable-lib}. @item -mrelocatable-lib @itemx -mno-relocatable-lib +@opindex mrelocatable-lib +@opindex mno-relocatable-lib On embedded PowerPC systems generate code that allows (does not allow) the program to be relocated to a different address at runtime. Modules compiled with @samp{-mrelocatable-lib} can be linked with either modules @@ -6249,49 +6687,63 @@ with modules compiled with the @samp{-mrelocatable} options. @item -mno-toc @itemx -mtoc +@opindex mno-toc +@opindex mtoc On System V.4 and embedded PowerPC systems do not (do) assume that register 2 contains a pointer to a global area pointing to the addresses used in the program. @item -mlittle @itemx -mlittle-endian +@opindex mlittle +@opindex mlittle-endian On System V.4 and embedded PowerPC systems compile code for the processor in little endian mode. The @samp{-mlittle-endian} option is the same as @samp{-mlittle}. @item -mbig @itemx -mbig-endian +@opindex mbig +@opindex mbig-endian On System V.4 and embedded PowerPC systems compile code for the processor in big endian mode. The @samp{-mbig-endian} option is the same as @samp{-mbig}. @item -mcall-sysv +@opindex mcall-sysv On System V.4 and embedded PowerPC systems compile code using calling conventions that adheres to the March 1995 draft of the System V Application Binary Interface, PowerPC processor supplement. This is the default unless you configured GCC using @samp{powerpc-*-eabiaix}. @item -mcall-sysv-eabi +@opindex mcall-sysv-eabi Specify both @samp{-mcall-sysv} and @samp{-meabi} options. @item -mcall-sysv-noeabi +@opindex mcall-sysv-noeabi Specify both @samp{-mcall-sysv} and @samp{-mno-eabi} options. @item -mcall-aix +@opindex mcall-aix On System V.4 and embedded PowerPC systems compile code using calling conventions that are similar to those used on AIX. This is the default if you configured GCC using @samp{powerpc-*-eabiaix}. @item -mcall-solaris +@opindex mcall-solaris On System V.4 and embedded PowerPC systems compile code for the Solaris operating system. @item -mcall-linux +@opindex mcall-linux On System V.4 and embedded PowerPC systems compile code for the Linux-based GNU system. @item -mprototype @itemx -mno-prototype +@opindex mprototype +@opindex mno-prototype On System V.4 and embedded PowerPC systems assume that all calls to variable argument functions are properly prototyped. Otherwise, the compiler must insert an instruction before every non prototyped call to @@ -6302,36 +6754,44 @@ registers in case the function takes a variable arguments. With will set or clear the bit. @item -msim +@opindex msim On embedded PowerPC systems, assume that the startup module is called @file{sim-crt0.o} and that the standard C libraries are @file{libsim.a} and @file{libc.a}. This is the default for @samp{powerpc-*-eabisim}. configurations. @item -mmvme +@opindex mmvme On embedded PowerPC systems, assume that the startup module is called @file{crt0.o} and the standard C libraries are @file{libmvme.a} and @file{libc.a}. @item -mads +@opindex mads On embedded PowerPC systems, assume that the startup module is called @file{crt0.o} and the standard C libraries are @file{libads.a} and @file{libc.a}. @item -myellowknife +@opindex myellowknife On embedded PowerPC systems, assume that the startup module is called @file{crt0.o} and the standard C libraries are @file{libyk.a} and @file{libc.a}. @item -mvxworks +@opindex mvxworks On System V.4 and embedded PowerPC systems, specify that you are compiling for a VxWorks system. @item -memb +@opindex memb On embedded PowerPC systems, set the @var{PPC_EMB} bit in the ELF flags header to indicate that @samp{eabi} extended relocations are used. @item -meabi @itemx -mno-eabi +@opindex meabi +@opindex mno-eabi On System V.4 and embedded PowerPC systems do (do not) adhere to the Embedded Applications Binary Interface (eabi) which is a set of modifications to the System V.4 specifications. Selecting @option{-meabi} @@ -6346,6 +6806,7 @@ small data area. The @samp{-meabi} option is on by default if you configured GCC using one of the @samp{powerpc*-*-eabi*} options. @item -msdata=eabi +@opindex msdata=eabi On System V.4 and embedded PowerPC systems, put small initialized @code{const} global and static data in the @samp{.sdata2} section, which is pointed to by register @code{r2}. Put small initialized @@ -6357,6 +6818,7 @@ incompatible with the @samp{-mrelocatable} option. The @samp{-msdata=eabi} option also sets the @samp{-memb} option. @item -msdata=sysv +@opindex msdata=sysv On System V.4 and embedded PowerPC systems, put small global and static data in the @samp{.sdata} section, which is pointed to by register @code{r13}. Put small uninitialized global and static data in the @@ -6366,11 +6828,14 @@ The @samp{-msdata=sysv} option is incompatible with the @item -msdata=default @itemx -msdata +@opindex msdata=default +@opindex msdata On System V.4 and embedded PowerPC systems, if @samp{-meabi} is used, compile code the same as @samp{-msdata=eabi}, otherwise compile code the same as @samp{-msdata=sysv}. @item -msdata-data +@opindex msdata-data On System V.4 and embedded PowerPC systems, put small global and static data in the @samp{.sdata} section. Put small uninitialized global and static data in the @samp{.sbss} section. Do not use register @code{r13} @@ -6379,11 +6844,14 @@ other @samp{-msdata} options are used. @item -msdata=none @itemx -mno-sdata +@opindex msdata=none +@opindex mno-sdata On embedded PowerPC systems, put all initialized global and static data in the @samp{.data} section, and all uninitialized data in the @samp{.bss} section. @item -G @var{num} +@opindex G @cindex smaller data references (PowerPC) @cindex .sdata/.sdata2 references (PowerPC) On embedded PowerPC systems, put global and static items less than or @@ -6394,6 +6862,8 @@ All modules should be compiled with the same @samp{-G @var{num}} value. @item -mregnames @itemx -mno-regnames +@opindex mregnames +@opindex mno-regnames On System V.4 and embedded PowerPC systems do (do not) emit register names in the assembly language output using symbolic forms. @@ -6408,17 +6878,21 @@ These @samp{-m} options are defined for the IBM RT PC: @table @gcctabopt @item -min-line-mul +@opindex min-line-mul Use an in-line code sequence for integer multiplies. This is the default. @item -mcall-lib-mul +@opindex mcall-lib-mul Call @code{lmul$$} for integer multiples. @item -mfull-fp-blocks +@opindex mfull-fp-blocks Generate full-size floating point data blocks, including the minimum amount of scratch space recommended by IBM. This is the default. @item -mminimum-fp-blocks +@opindex 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. @@ -6426,22 +6900,26 @@ be allocated dynamically. @cindex @file{varargs.h} and RT PC @cindex @file{stdarg.h} and RT PC @item -mfp-arg-in-fpregs +@opindex 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 @code{varargs.h} and @code{stdargs.h} will not work with floating point operands if this option is specified. @item -mfp-arg-in-gregs +@opindex mfp-arg-in-gregs Use the normal calling convention for floating point arguments. This is the default. @item -mhc-struct-return +@opindex 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 the option @samp{-fpcc-struct-return} for compatibility with the Portable C Compiler (pcc). @item -mnohc-struct-return +@opindex 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 the option @samp{-fpcc-struct-return} or the @@ -6456,6 +6934,7 @@ These @samp{-m} options are defined for the MIPS family of computers: @table @gcctabopt @item -mcpu=@var{cpu type} +@opindex mcpu Assume the defaults for the machine type @var{cpu type} when scheduling instructions. The choices for @var{cpu type} are @samp{r2000}, @samp{r3000}, @samp{r3900}, @samp{r4000}, @samp{r4100}, @samp{r4300}, @samp{r4400}, @@ -6469,48 +6948,59 @@ of the MIPS ISA (instruction set architecture) without a @samp{-mipsX} or @samp{-mabi} switch being used. @item -mips1 +@opindex mips1 Issue instructions from level 1 of the MIPS ISA. This is the default. @samp{r3000} is the default @var{cpu type} at this ISA level. @item -mips2 +@opindex mips2 Issue instructions from level 2 of the MIPS ISA (branch likely, square root instructions). @samp{r6000} is the default @var{cpu type} at this ISA level. @item -mips3 +@opindex mips3 Issue instructions from level 3 of the MIPS ISA (64-bit instructions). @samp{r4000} is the default @var{cpu type} at this ISA level. @item -mips4 +@opindex mips4 Issue instructions from level 4 of the MIPS ISA (conditional move, prefetch, enhanced FPU instructions). @samp{r8000} is the default @var{cpu type} at this ISA level. @item -mfp32 +@opindex mfp32 Assume that 32 32-bit floating point registers are available. This is the default. @item -mfp64 +@opindex mfp64 Assume that 32 64-bit floating point registers are available. This is the default when the @samp{-mips3} option is used. @item -mgp32 +@opindex mgp32 Assume that 32 32-bit general purpose registers are available. This is the default. @item -mgp64 +@opindex mgp64 Assume that 32 64-bit general purpose registers are available. This is the default when the @samp{-mips3} option is used. @item -mint64 +@opindex mint64 Force int and long types to be 64 bits wide. See @samp{-mlong32} for an explanation of the default, and the width of pointers. @item -mlong64 +@opindex mlong64 Force long types to be 64 bits wide. See @samp{-mlong32} for an explanation of the default, and the width of pointers. @item -mlong32 +@opindex mlong32 Force long, int, and pointer types to be 32 bits wide. If none of @samp{-mlong32}, @samp{-mlong64}, or @samp{-mint64} are set, @@ -6528,6 +7018,11 @@ registers (which in turn depends on the ISA). @itemx -mabi=n32 @itemx -mabi=64 @itemx -mabi=eabi +@opindex mabi=32 +@opindex mabi=o64 +@opindex mabi=n32 +@opindex mabi=64 +@opindex mabi=eabi Generate code for the indicated ABI. The default instruction level is @samp{-mips1} for @samp{32}, @samp{-mips3} for @samp{n32}, and @samp{-mips4} otherwise. Conversely, with @samp{-mips1} or @@ -6535,6 +7030,7 @@ Generate code for the indicated ABI. The default instruction level is is @samp{64}. @item -mmips-as +@opindex mmips-as Generate code for the MIPS assembler, and invoke @file{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 @@ -6543,12 +7039,15 @@ switches are used, the @file{mips-tfile} program will encapsulate the stabs within MIPS ECOFF. @item -mgas +@opindex mgas Generate code for the GNU assembler. This is the default on the OSF/1 reference platform, using the OSF/rose object format. Also, this is the default if the configure option @samp{--with-gnu-as} is used. @item -msplit-addresses @itemx -mno-split-addresses +@opindex msplit-addresses +@opindex mno-split-addresses Generate code to load the high and low parts of address constants separately. This allows @code{gcc} to optimize away redundant loads of the high order bits of addresses. This optimization requires GNU as and GNU ld. @@ -6557,6 +7056,8 @@ GNU as and GNU ld are standard. @item -mrnames @itemx -mno-rnames +@opindex mrnames +@opindex mno-rnames The @samp{-mrnames} switch says to output code using the MIPS software names for the registers, instead of the hardware names (ie, @var{a0} instead of @var{$4}). The only known assembler that supports this option @@ -6564,6 +7065,8 @@ is the Algorithmics assembler. @item -mgpopt @itemx -mno-gpopt +@opindex mgpopt +@opindex mno-gpopt The @samp{-mgpopt} switch says to write all of the data declarations before the instructions in the text section, this allows the MIPS assembler to generate one word memory references instead of using two @@ -6572,6 +7075,8 @@ optimization is selected. @item -mstats @itemx -mno-stats +@opindex mstats +@opindex mno-stats For each non-inline function processed, the @samp{-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 @@ -6579,12 +7084,16 @@ size, etc.). @item -mmemcpy @itemx -mno-memcpy +@opindex mmemcpy +@opindex mno-memcpy The @samp{-mmemcpy} switch makes all block moves call the appropriate string function (@samp{memcpy} or @samp{bcopy}) instead of possibly generating inline code. @item -mmips-tfile @itemx -mno-mips-tfile +@opindex mmips-tfile +@opindex mno-mips-tfile The @samp{-mno-mips-tfile} switch causes the compiler not postprocess the object file with the @file{mips-tfile} program, after the MIPS assembler has generated it to add debug support. If @@ -6597,6 +7106,7 @@ be used when there are bugs in the @file{mips-tfile} program that prevents compilation. @item -msoft-float +@opindex msoft-float Generate output containing library calls for floating point. @strong{Warning:} the requisite libraries are not part of GCC. Normally the facilities of the machine's usual C compiler are used, but @@ -6605,17 +7115,22 @@ own arrangements to provide suitable library functions for cross-compilation. @item -mhard-float +@opindex mhard-float Generate output containing floating point instructions. This is the default if you use the unmodified sources. @item -mabicalls @itemx -mno-abicalls +@opindex mabicalls +@opindex mno-abicalls Emit (or do not emit) the pseudo operations @samp{.abicalls}, @samp{.cpload}, and @samp{.cprestore} that some System V.4 ports use for position independent code. @item -mlong-calls @itemx -mno-long-calls +@opindex mlong-calls +@opindex mno-long-calls Do all calls with the @samp{JALR} instruction, which requires loading up a function's address into a register before the call. You need to use this switch, if you call outside of the current @@ -6623,11 +7138,15 @@ You need to use this switch, if you call outside of the current @item -mhalf-pic @itemx -mno-half-pic +@opindex mhalf-pic +@opindex mno-half-pic Put pointers to extern references into the data section and load them up, rather than put the references in the text section. @item -membedded-pic @itemx -mno-embedded-pic +@opindex membedded-pic +@opindex mno-embedded-pic Generate PIC code suitable for some embedded systems. All calls are made using PC relative address, and all data is addressed using the $gp register. No more than 65536 bytes of global data may be used. This @@ -6636,6 +7155,8 @@ only works on targets which use ECOFF; it does not work with ELF. @item -membedded-data @itemx -mno-embedded-data +@opindex membedded-data +@opindex mno-embedded-data Allocate variables to the read-only data section first if possible, then next in the small data section if possible, otherwise in data. This gives slightly slower code than the default, but reduces the amount of RAM required @@ -6643,11 +7164,15 @@ when executing, and thus may be preferred for some embedded systems. @item -muninit-const-in-rodata @itemx -mno-uninit-const-in-rodata +@opindex muninit-const-in-rodata +@opindex mno-uninit-const-in-rodata When used together with -membedded-data, it will always store uninitialized const variables in the read-only data section. @item -msingle-float @itemx -mdouble-float +@opindex msingle-float +@opindex mdouble-float The @samp{-msingle-float} switch tells gcc to assume that the floating point coprocessor only supports single precision operations, as on the @samp{r4650} chip. The @samp{-mdouble-float} switch permits gcc to use @@ -6655,30 +7180,39 @@ double precision operations. This is the default. @item -mmad @itemx -mno-mad +@opindex mmad +@opindex mno-mad Permit use of the @samp{mad}, @samp{madu} and @samp{mul} instructions, as on the @samp{r4650} chip. @item -m4650 +@opindex m4650 Turns on @samp{-msingle-float}, @samp{-mmad}, and, at least for now, @samp{-mcpu=r4650}. @item -mips16 @itemx -mno-mips16 +@opindex mips16 +@opindex mno-mips16 Enable 16-bit instructions. @item -mentry +@opindex mentry Use the entry and exit pseudo ops. This option can only be used with @samp{-mips16}. @item -EL +@opindex EL Compile code for the processor in little endian mode. The requisite libraries are assumed to exist. @item -EB +@opindex EB Compile code for the processor in big endian mode. The requisite libraries are assumed to exist. @item -G @var{num} +@opindex G @cindex smaller data references (MIPS) @cindex gp-relative references (MIPS) Put global and static items less than or equal to @var{num} bytes into @@ -6692,15 +7226,18 @@ All modules should be compiled with the same @samp{-G @var{num}} value. @item -nocpp +@opindex nocpp Tell the MIPS assembler to not run its preprocessor over user assembler files (with a @samp{.s} suffix) when assembling them. @item -mfix7000 +@opindex mfix7000 Pass an option to gas which will cause nops to be inserted if the read of the destination register of an mfhi or mflo instruction occurs in the following two instructions. @item -no-crt0 +@opindex no-crt0 Do not include the default crt0. @end table @@ -6720,6 +7257,7 @@ These @samp{-m} options are defined for the i386 family of computers: @table @gcctabopt @item -mcpu=@var{cpu type} +@opindex mcpu Assume the defaults for the machine type @var{cpu type} when scheduling instructions. The choices for @var{cpu type} are @samp{i386}, @samp{i486}, @samp{i586}, @samp{i686}, @samp{pentium}, @@ -6733,6 +7271,7 @@ is equivalent to @samp{pentiumpro}. @samp{k6} and @samp{athlon} are the AMD chips as opposed to the Intel ones. @item -march=@var{cpu type} +@opindex march Generate instructions for the machine type @var{cpu type}. The choices for @var{cpu type} are the same as for @samp{-mcpu}. Moreover, specifying @samp{-march=@var{cpu type}} implies @samp{-mcpu=@var{cpu type}}. @@ -6741,19 +7280,27 @@ specifying @samp{-march=@var{cpu type}} implies @samp{-mcpu=@var{cpu type}}. @itemx -m486 @itemx -mpentium @itemx -mpentiumpro +@opindex m386 +@opindex m486 +@opindex mpentium +@opindex mpentiumpro Synonyms for -mcpu=i386, -mcpu=i486, -mcpu=pentium, and -mcpu=pentiumpro respectively. These synonyms are deprecated. @item -mintel-syntax +@opindex mintel-syntax Emit assembly using Intel syntax opcodes instead of AT&T syntax. @item -mieee-fp @itemx -mno-ieee-fp +@opindex mieee-fp +@opindex mno-ieee-fp Control whether or not the compiler uses IEEE floating point comparisons. These handle correctly the case where the result of a comparison is unordered. @item -msoft-float +@opindex msoft-float Generate output containing library calls for floating point. @strong{Warning:} the requisite libraries are not part of GCC. Normally the facilities of the machine's usual C compiler are used, but @@ -6766,6 +7313,7 @@ register stack, some floating point opcodes may be emitted even if @samp{-msoft-float} is used. @item -mno-fp-ret-in-387 +@opindex mno-fp-ret-in-387 Do not use the FPU registers for return values of functions. The usual calling convention has functions return values of types @@ -6777,6 +7325,7 @@ The option @samp{-mno-fp-ret-in-387} causes such values to be returned in ordinary CPU registers instead. @item -mno-fancy-math-387 +@opindex mno-fancy-math-387 Some 387 emulators do not support the @code{sin}, @code{cos} and @code{sqrt} instructions for the 387. Specify this option to avoid generating those instructions. This option is the default on FreeBSD. @@ -6785,6 +7334,8 @@ also use the @samp{-funsafe-math-optimizations} switch. @item -malign-double @itemx -mno-align-double +@opindex malign-double +@opindex mno-align-double Control whether GCC aligns @code{double}, @code{long double}, and @code{long long} variables on a two word boundary or a one word boundary. Aligning @code{double} variables on a two word boundary will @@ -6793,6 +7344,8 @@ expense of more memory. @item -m128bit-long-double @itemx -m128bit-long-double +@opindex m128bit-long-double +@opindex m128bit-long-double Control the size of @code{long double} type. i386 application binary interface specify the size to be 12 bytes, while modern architectures (Pentium and newer) preffer @code{long double} aligned to 8 or 16 byte boundary. This is @@ -6805,22 +7358,29 @@ will be modified. @item -m96bit-long-double @itemx -m96bit-long-double +@opindex m96bit-long-double +@opindex m96bit-long-double Set the size of @code{long double} to 96 bits as required by the i386 application binary interface. This is the default. @item -msvr3-shlib @itemx -mno-svr3-shlib +@opindex msvr3-shlib +@opindex mno-svr3-shlib Control whether GCC places uninitialized locals into @code{bss} or @code{data}. @samp{-msvr3-shlib} places these locals into @code{bss}. These options are meaningful only on System V Release 3. @item -mno-wide-multiply @itemx -mwide-multiply +@opindex mno-wide-multiply +@opindex mwide-multiply Control whether GCC uses the @code{mul} and @code{imul} that produce 64-bit results in @code{eax:edx} from 32-bit operands to do @code{long long} multiplies and 32-bit division by constants. @item -mrtd +@opindex mrtd Use a different function-calling convention, in which functions that take a fixed number of arguments return with the @code{ret} @var{num} instruction, which pops their arguments while returning. This saves one @@ -6846,6 +7406,7 @@ function with too many arguments. (Normally, extra arguments are harmlessly ignored.) @item -mregparm=@var{num} +@opindex mregparm Control how many registers are used to pass integer arguments. By default, no registers are used to pass arguments, and at most 3 registers can be used. You can control this behavior for a specific @@ -6858,6 +7419,7 @@ value, including any libraries. This includes the system libraries and startup modules. @item -mpreferred-stack-boundary=@var{num} +@opindex mpreferred-stack-boundary Attempt to keep the stack boundary aligned to a 2 raised to @var{num} byte boundary. If @samp{-mpreferred-stack-boundary} is not specified, the default is 4 (16 bytes or 128 bits). @@ -6883,14 +7445,14 @@ may want to reduce the preferred alignment to @samp{-mpreferred-stack-boundary=2}. @item -mpush-args -@kindex -mpush-args +@opindex mpush-args Use PUSH operations to store outgoing parameters. This method is shorter and usually equally fast as method using SUB/MOV operations and is enabled by default. In some cases disabling it may improve performance because of improved scheduling and reduced dependencies. @item -maccumulate-outgoing-args -@kindex -maccumulate-outgoing-args +@opindex maccumulate-outgoing-args If enabled, the maximum amount of space required for outgoing arguments will be computed in the function prologue. This in faster on most modern CPUs because of reduced dependencies, improved scheduling and reduced stack usage @@ -6898,7 +7460,7 @@ when preferred stack boundary is not equal to 2. The drawback is a notable increase in code size. This switch implies -mno-push-args. @item -mthreads -@kindex -mthreads +@opindex mthreads Support thread-safe exception handling on @samp{Mingw32}. Code that relies on thread-safe exception handling must compile and link all code with the @samp{-mthreads} option. When compiling, @samp{-mthreads} defines @@ -6906,20 +7468,20 @@ on thread-safe exception handling must compile and link all code with the @samp{-lmingwthrd} which cleans up per thread exception handling data. @item -mno-align-stringops -@kindex -mno-align-stringops +@opindex mno-align-stringops Do not align destination of inlined string operations. This switch reduces code size and improves performance in case the destination is already aligned, but gcc don't know about it. @item -minline-all-stringops -@kindex -minline-all-stringops +@opindex minline-all-stringops By default GCC inlines string operations only when destination is known to be aligned at least to 4 byte boundary. This enables more inlining, increase code size, but may improve performance of code that depends on fast memcpy, strlen and memset for short lengths. @item -momit-leaf-frame-pointer -@kindex -momit-leaf-frame-pointer +@opindex momit-leaf-frame-pointer Don't keep the frame pointer in a register for leaf functions. This avoids the instructions to save, set up and restore frame pointers and makes an extra register available in leaf functions. The option @@ -6935,6 +7497,7 @@ These @samp{-m} options are defined for the HPPA family of computers: @table @gcctabopt @item -march=@var{architecture type} +@opindex march Generate code for the specified architecture. The choices for @var{architecture type} are @samp{1.0} for PA 1.0, @samp{1.1} for PA 1.1, and @samp{2.0} for PA 2.0 processors. Refer to @@ -6950,35 +7513,44 @@ support. @item -mpa-risc-1-0 @itemx -mpa-risc-1-1 @itemx -mpa-risc-2-0 +@opindex mpa-risc-1-0 +@opindex mpa-risc-1-1 +@opindex mpa-risc-2-0 Synonyms for -march=1.0, -march=1.1, and -march=2.0 respectively. @item -mbig-switch +@opindex mbig-switch Generate code suitable for big switch tables. Use this option only if the assembler/linker complain about out of range branches within a switch table. @item -mjump-in-delay +@opindex mjump-in-delay Fill delay slots of function calls with unconditional jump instructions by modifying the return pointer for the function call to be the target of the conditional jump. @item -mdisable-fpregs +@opindex 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. @item -mdisable-indexing +@opindex mdisable-indexing Prevent the compiler from using indexing address modes. This avoids some rather obscure problems when compiling MIG generated code under MACH. @item -mno-space-regs +@opindex mno-space-regs Generate code that assumes the target has no space registers. This allows GCC to generate faster indirect calls and use unscaled index address modes. Such code is suitable for level 0 PA systems and kernels. @item -mfast-indirect-calls +@opindex mfast-indirect-calls Generate code that assumes calls never cross space boundaries. This allows GCC to emit code which performs faster indirect calls. @@ -6986,17 +7558,21 @@ This option will not work in the presence of shared libraries or nested functions. @item -mlong-load-store +@opindex mlong-load-store Generate 3-instruction load and store sequences as sometimes required by the HP-UX 10 linker. This is equivalent to the @samp{+k} option to the HP compilers. @item -mportable-runtime +@opindex mportable-runtime Use the portable calling conventions proposed by HP for ELF systems. @item -mgas +@opindex mgas Enable the use of assembler directives only GAS understands. @item -mschedule=@var{cpu type} +@opindex mschedule Schedule code according to the constraints for the machine type @var{cpu type}. The choices for @var{cpu type} are @samp{700} @samp{7100}, @samp{7100LC}, @samp{7200}, and @samp{8000}. Refer to @@ -7004,11 +7580,13 @@ Schedule code according to the constraints for the machine type proper scheduling option for your machine. @item -mlinker-opt +@opindex mlinker-opt Enable the optimization pass in the HPUX linker. Note this makes symbolic debugging impossible. It also triggers a bug in the HPUX 8 and HPUX 9 linkers in which they give bogus error messages when linking some programs. @item -msoft-float +@opindex msoft-float Generate output containing library calls for floating point. @strong{Warning:} the requisite libraries are not available for all HPPA targets. Normally the facilities of the machine's usual C compiler are @@ -7030,10 +7608,17 @@ this to work. These @samp{-m} options are defined for the Intel 960 implementations: @table @gcctabopt -@item -m@var{cpu type} -Assume the defaults for the machine type @var{cpu type} for some of +@item -m@var{cpu-type} +@opindex mka +@opindex mkb +@opindex mmc +@opindex mca +@opindex mcf +@opindex msa +@opindex msb +Assume the defaults for the machine type @var{cpu-type} for some of the other options, including instruction scheduling, floating point -support, and addressing modes. The choices for @var{cpu type} are +support, and addressing modes. The choices for @var{cpu-type} are @samp{ka}, @samp{kb}, @samp{mc}, @samp{ca}, @samp{cf}, @samp{sa}, and @samp{sb}. The default is @@ -7041,12 +7626,16 @@ The default is @item -mnumerics @itemx -msoft-float +@opindex mnumerics +@opindex msoft-float The @samp{-mnumerics} option indicates that the processor does support floating-point instructions. The @samp{-msoft-float} option indicates that floating-point support should not be assumed. @item -mleaf-procedures @itemx -mno-leaf-procedures +@opindex mleaf-procedures +@opindex mno-leaf-procedures Do (or do not) attempt to alter leaf procedures to be callable with the @code{bal} instruction as well as @code{call}. This will result in more efficient code for explicit calls when the @code{bal} instruction can be @@ -7056,6 +7645,8 @@ support this optimization. @item -mtail-call @itemx -mno-tail-call +@opindex mtail-call +@opindex 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 @@ -7064,6 +7655,8 @@ cases where this is not valid is not totally complete. The default is @item -mcomplex-addr @itemx -mno-complex-addr +@opindex mcomplex-addr +@opindex 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. @@ -7072,33 +7665,46 @@ the CB and CC. @item -mcode-align @itemx -mno-code-align +@opindex mcode-align +@opindex 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. @ignore @item -mclean-linkage @itemx -mno-clean-linkage +@opindex mclean-linkage +@opindex mno-clean-linkage These options are not fully implemented. @end ignore @item -mic-compat @itemx -mic2.0-compat @itemx -mic3.0-compat +@opindex mic-compat +@opindex mic2.0-compat +@opindex mic3.0-compat Enable compatibility with iC960 v2.0 or v3.0. @item -masm-compat @itemx -mintel-asm +@opindex masm-compat +@opindex mintel-asm Enable compatibility with the iC960 assembler. @item -mstrict-align @itemx -mno-strict-align +@opindex mstrict-align +@opindex mno-strict-align Do not permit (do permit) unaligned accesses. @item -mold-align +@opindex mold-align Enable structure-alignment compatibility with Intel's gcc release version 1.3 (based on gcc 1.37). This option implies @samp{-mstrict-align}. @item -mlong-double-64 +@opindex mlong-double-64 Implement type @samp{long double} as 64-bit floating point numbers. Without the option @samp{long double} is implemented by 80-bit floating point numbers. The only reason we have it because there is @@ -7116,6 +7722,8 @@ These @samp{-m} options are defined for the DEC Alpha implementations: @table @gcctabopt @item -mno-soft-float @itemx -msoft-float +@opindex mno-soft-float +@opindex msoft-float Use (do not use) the hardware floating-point instructions for floating-point operations. When @option{-msoft-float} is specified, functions in @file{libgcc.a} will be used to perform floating-point @@ -7131,6 +7739,8 @@ required to have floating-point registers. @item -mfp-reg @itemx -mno-fp-regs +@opindex mfp-reg +@opindex mno-fp-regs Generate code that uses (does not use) the floating-point register set. @option{-mno-fp-regs} implies @option{-msoft-float}. If the floating-point register set is not used, floating point operands are passed in integer @@ -7144,6 +7754,7 @@ 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. @item -mieee +@opindex mieee The Alpha architecture implements floating-point hardware optimized for maximum performance. It is mostly compliant with the IEEE floating point standard. However, for full compliance, software assistance is @@ -7158,6 +7769,7 @@ infinity. Other Alpha compilers call this option @option{-ieee_with_no_inexact}. @item -mieee-with-inexact +@opindex mieee-with-inexact @c overfull hbox here --bob 22 jul96 @c original text between ignore ... end ignore @ignore @@ -7188,6 +7800,7 @@ option @samp{-ieee_with_inexact}. @c end changes to prevent overfull hboxes @item -mfp-trap-mode=@var{trap mode} +@opindex mfp-trap-mode This option controls what floating-point related traps are enabled. Other Alpha compilers call this option @samp{-fptm }@var{trap mode}. The trap mode can be set to one of four values: @@ -7211,6 +7824,7 @@ Like @samp{su}, but inexact traps are enabled as well. @end table @item -mfp-rounding-mode=@var{rounding mode} +@opindex mfp-rounding-mode Selects the IEEE rounding mode. Other Alpha compilers call this option @samp{-fprm }@var{rounding mode}. The @var{rounding mode} can be one of: @@ -7236,6 +7850,7 @@ rounding towards plus infinity. Thus, unless your program modifies the @end table @item -mtrap-precision=@var{trap precision} +@opindex mtrap-precision In the Alpha architecture, floating point traps are imprecise. This means without software assistance it is impossible to recover from a floating trap and program execution normally needs to be terminated. @@ -7262,6 +7877,7 @@ Other Alpha compilers provide the equivalent options called @samp{-scope_safe} and @samp{-resumption_safe}. @item -mieee-conformant +@opindex mieee-conformant This option marks the generated code as IEEE conformant. You must not use this option unless you also specify @samp{-mtrap-precision=i} and either @samp{-mfp-trap-mode=su} or @samp{-mfp-trap-mode=sui}. Its only effect @@ -7270,6 +7886,7 @@ generated assembly file. Under DEC Unix, this has the effect that IEEE-conformant math library routines will be linked in. @item -mbuild-constants +@opindex mbuild-constants Normally GCC examines a 32- or 64-bit integer constant to see if it can construct it from smaller constants in two or three instructions. If it cannot, it will output the constant as a literal and @@ -7284,6 +7901,8 @@ before it can find the variables and constants in its own data segment. @item -malpha-as @itemx -mgas +@opindex malpha-as +@opindex mgas Select whether to generate code to be assembled by the vendor-supplied assembler (@samp{-malpha-as}) or by the GNU assembler @samp{-mgas}. @@ -7293,12 +7912,19 @@ assembler (@samp{-malpha-as}) or by the GNU assembler @samp{-mgas}. @itemx -mno-cix @itemx -mmax @itemx -mno-max +@opindex mbwx +@opindex mno-bwx +@opindex mcix +@opindex mno-cix +@opindex mmax +@opindex mno-max Indicate whether GCC should generate code to use the optional BWX, CIX, and MAX instruction sets. The default is to use the instruction sets supported by the CPU type specified via @samp{-mcpu=} option or that of the CPU on which GCC was built if none was specified. @item -mcpu=@var{cpu_type} +@opindex mcpu Set the instruction set, register set, and instruction scheduling parameters for machine type @var{cpu_type}. You can specify either the @samp{EV} style name or the corresponding chip number. GCC @@ -7334,6 +7960,7 @@ for the EV6) and supports the BWX, CIX, and MAX extensions. @end table @item -mmemory-latency=@var{time} +@opindex mmemory-latency Sets the latency the scheduler should assume for typical memory references as seen by the application. This number is highly dependent on the memory access patterns used by the application @@ -7364,9 +7991,11 @@ These @samp{-m} options are defined for the Clipper implementations: @table @gcctabopt @item -mc300 +@opindex mc300 Produce code for a C300 Clipper processor. This is the default. @item -mc400 +@opindex mc400 Produce code for a C400 Clipper processor i.e. use floating point registers f8..f15. @end table @@ -7378,23 +8007,29 @@ These @samp{-m} options are defined for the H8/300 implementations: @table @gcctabopt @item -mrelax +@opindex mrelax Shorten some address references at link time, when possible; uses the linker option @samp{-relax}. @xref{H8/300,, @code{ld} and the H8/300, ld.info, Using ld}, for a fuller description. @item -mh +@opindex mh Generate code for the H8/300H. @item -ms +@opindex ms Generate code for the H8/S. @item -ms2600 +@opindex ms2600 Generate code for the H8/S2600. This switch must be used with -ms. @item -mint32 +@opindex mint32 Make @code{int} data 32 bits by default. @item -malign-300 +@opindex malign-300 On the H8/300H and H8/S, use the same alignment rules as for the H8/300. The default for the H8/300H and H8/S is to align longs and floats on 4 byte boundaries. @@ -7409,75 +8044,96 @@ These @samp{-m} options are defined for the SH implementations: @table @gcctabopt @item -m1 +@opindex m1 Generate code for the SH1. @item -m2 +@opindex m2 Generate code for the SH2. @item -m3 +@opindex m3 Generate code for the SH3. @item -m3e +@opindex m3e Generate code for the SH3e. @item -m4-nofpu +@opindex m4-nofpu Generate code for the SH4 without a floating-point unit. @item -m4-single-only +@opindex m4-single-only Generate code for the SH4 with a floating-point unit that only supports single-precision arithmentic. @item -m4-single +@opindex m4-single Generate code for the SH4 assuming the floating-point unit is in single-precision mode by default. @item -m4 +@opindex m4 Generate code for the SH4. @item -mb +@opindex mb Compile code for the processor in big endian mode. @item -ml +@opindex ml Compile code for the processor in little endian mode. @item -mdalign +@opindex mdalign Align doubles at 64-bit boundaries. Note that this changes the calling conventions, and thus some functions from the standard C library will not work unless you recompile it first with -mdalign. @item -mrelax +@opindex mrelax Shorten some address references at link time, when possible; uses the linker option @samp{-relax}. @item -mbigtable +@opindex mbigtable Use 32-bit offsets in @code{switch} tables. The default is to use 16-bit offsets. @item -mfmovd +@opindex mfmovd Enable the use of the instruction @code{fmovd}. @item -mhitachi +@opindex mhitachi Comply with the calling conventions defined by Hitachi. @item -mnomacsave +@opindex mnomacsave Mark the @code{MAC} register as call-clobbered, even if @option{-mhitachi} is given. @item -misize +@opindex misize Dump instruction size and location in the assembly code. @item -mpadstruct +@opindex mpadstruct This option is deprecated. It pads structures to multiple of 4 bytes, which is incompatible with the SH ABI. @item -mspace +@opindex mspace Optimize for space instead of speed. Implied by @option{-Os}. @item -mprefergot +@opindex mprefergot When generating position-independent code, emit function calls using the Global Offset Table instead of the Procedure Linkage Table. @item -musermode +@opindex musermode Generate a library function call to invalidate instruction cache entries, after fixing up a trampoline. This library function call doesn't assume it can write to the whole memory address space. This @@ -7492,22 +8148,27 @@ compatibility with other compilers on those systems: @table @gcctabopt @item -G +@opindex G Create a shared object. It is recommended that @samp{-symbolic} or @samp{-shared} be used instead. @item -Qy +@opindex Qy Identify the versions of each tool used by the compiler, in a @code{.ident} assembler directive in the output. @item -Qn +@opindex Qn Refrain from adding @code{.ident} directives to the output file (this is the default). @item -YP\,@var{dirs} +@opindex YP Search the directories @var{dirs}, and no others, for libraries specified with @samp{-l}. @item -Ym\,@var{dir} +@opindex Ym Look in the directory @var{dir} to find the M4 preprocessor. The assembler uses this option. @c This is supposed to go with a -Yd for predefined M4 macro files, but @@ -7523,6 +8184,7 @@ These @samp{-m} options are defined for TMS320C3x/C4x implementations: @table @gcctabopt @item -mcpu=@var{cpu_type} +@opindex mcpu Set the instruction set, register set, and instruction scheduling parameters for machine type @var{cpu_type}. Supported values for @var{cpu_type} are @samp{c30}, @samp{c31}, @samp{c32}, @samp{c40}, and @@ -7533,6 +8195,10 @@ TMS320C40. @item -mbig @itemx -msmall-memory @itemx -msmall +@opindex mbig-memory +@opindex mbig +@opindex msmall-memory +@opindex msmall Generates code for the big or small memory model. The small memory model assumed that all data fits into one 64K word page. At run-time the data page (DP) register must be set to point to the 64K page @@ -7542,11 +8208,15 @@ memory access. @item -mbk @itemx -mno-bk +@opindex mbk +@opindex mno-bk Allow (disallow) allocation of general integer operands into the block count register BK. @item -mdb @itemx -mno-db +@opindex mdb +@opindex mno-db Enable (disable) generation of code using decrement and branch, DBcond(D), instructions. This is enabled by default for the C4x. To be on the safe side, this is disabled for the C3x, since the maximum @@ -7559,6 +8229,8 @@ efficient code, in cases where the RPTB instruction cannot be utilised. @item -mdp-isr-reload @itemx -mparanoid +@opindex mdp-isr-reload +@opindex mparanoid Force the DP register to be saved on entry to an interrupt service routine (ISR), reloaded to point to the data section, and restored on exit from the ISR. This should not be required unless someone has @@ -7567,6 +8239,8 @@ an object library. @item -mmpyi @itemx -mno-mpyi +@opindex mmpyi +@opindex mno-mpyi For the C3x use the 24-bit MPYI instruction for integer multiplies instead of a library call to guarantee 32-bit results. Note that if one of the operands is a constant, then the multiplication will be performed @@ -7575,6 +8249,8 @@ then squaring operations are performed inline instead of a library call. @item -mfast-fix @itemx -mno-fast-fix +@opindex mfast-fix +@opindex mno-fast-fix The C3x/C4x FIX instruction to convert a floating point value to an integer value chooses the nearest integer less than or equal to the floating point value rather than to the nearest integer. Thus if the @@ -7585,6 +8261,8 @@ code required to correct the result. @item -mrptb @itemx -mno-rptb +@opindex mrptb +@opindex mno-rptb Enable (disable) generation of repeat block sequences using the RPTB instruction for zero overhead looping. The RPTB construct is only used for innermost loops that do not call functions or jump across the loop @@ -7594,6 +8272,8 @@ This is enabled by default with -O2. @item -mrpts=@var{count} @itemx -mno-rpts +@opindex mrpts +@opindex mno-rpts Enable (disable) the use of the single instruction repeat instruction RPTS. If a repeat block contains a single instruction, and the loop count can be guaranteed to be less than the value @var{count}, GCC will @@ -7606,6 +8286,8 @@ instruction, it is disabled by default. @item -mloop-unsigned @itemx -mno-loop-unsigned +@opindex mloop-unsigned +@opindex mno-loop-unsigned The maximum iteration count when using RPTS and RPTB (and DB on the C40) is 2^31 + 1 since these instructions test if the iteration count is negative to terminate the loop. If the iteration count is unsigned @@ -7613,6 +8295,7 @@ there is a possibility than the 2^31 + 1 maximum iteration count may be exceeded. This switch allows an unsigned iteration count. @item -mti +@opindex mti Try to emit an assembler syntax that the TI assembler (asm30) is happy with. This also enforces compatibility with the API employed by the TI C3x C compiler. For example, long doubles are passed as structures @@ -7620,17 +8303,23 @@ rather than in floating point registers. @item -mregparm @itemx -mmemparm +@opindex mregparm +@opindex mmemparm Generate code that uses registers (stack) for passing arguments to functions. By default, arguments are passed in registers where possible rather than by pushing arguments on to the stack. @item -mparallel-insns @itemx -mno-parallel-insns +@opindex mparallel-insns +@opindex mno-parallel-insns Allow the generation of parallel instructions. This is enabled by default with -O2. @item -mparallel-mpy @itemx -mno-parallel-mpy +@opindex mparallel-mpy +@opindex mno-parallel-mpy Allow the generation of MPY||ADD and MPY||SUB parallel instructions, provided -mparallel-insns is also specified. These instructions have tight register constraints which can pessimize the code generation @@ -7647,12 +8336,16 @@ These @samp{-m} options are defined for V850 implementations: @table @gcctabopt @item -mlong-calls @itemx -mno-long-calls +@opindex mlong-calls +@opindex mno-long-calls Treat all calls as being far away (near). If calls are assumed to be far away, the compiler will always load the functions address up into a register, and call indirect through the pointer. @item -mno-ep @itemx -mep +@opindex mno-ep +@opindex mep Do not optimize (do optimize) basic blocks that use the same index pointer 4 or more times to copy pointer into the @code{ep} register, and use the shorter @code{sld} and @code{sst} instructions. The @samp{-mep} @@ -7660,6 +8353,8 @@ option is on by default if you optimize. @item -mno-prolog-function @itemx -mprolog-function +@opindex mno-prolog-function +@opindex mprolog-function Do not use (do use) external functions to save and restore registers at the prolog and epilog of a function. The external functions are slower, but use less code space if more than one function saves the same number @@ -7667,27 +8362,33 @@ of registers. The @samp{-mprolog-function} option is on by default if you optimize. @item -mspace +@opindex mspace Try to make the code as small as possible. At present, this just turns on the @samp{-mep} and @samp{-mprolog-function} options. @item -mtda=@var{n} +@opindex mtda Put static or global variables whose size is @var{n} bytes or less into the tiny data area that register @code{ep} points to. The tiny data area can hold up to 256 bytes in total (128 bytes for byte references). @item -msda=@var{n} +@opindex msda Put static or global variables whose size is @var{n} bytes or less into the small data area that register @code{gp} points to. The small data area can hold up to 64 kilobytes. @item -mzda=@var{n} +@opindex mzda Put static or global variables whose size is @var{n} bytes or less into the first 32 kilobytes of memory. @item -mv850 +@opindex mv850 Specify that the target processor is the V850. @item -mbig-switch +@opindex mbig-switch Generate code suitable for big switch tables. Use this option only if the assembler/linker complain about out of range branches within a switch table. @@ -7701,12 +8402,15 @@ These options are defined for ARC implementations: @table @gcctabopt @item -EL +@opindex EL Compile code for little endian mode. This is the default. @item -EB +@opindex EB Compile code for big endian mode. @item -mmangle-cpu +@opindex mmangle-cpu Prepend the name of the cpu to all public symbol names. In multiple-processor systems, there are many ARC variants with different instruction and register set characteristics. This flag prevents code @@ -7715,6 +8419,7 @@ No facility exists for handling variants that are "almost identical". This is an all or nothing option. @item -mcpu=@var{cpu} +@opindex mcpu Compile code for ARC variant @var{cpu}. Which variants are supported depend on the configuration. All variants support @samp{-mcpu=base}, this is the default. @@ -7722,6 +8427,9 @@ All variants support @samp{-mcpu=base}, this is the default. @item -mtext=@var{text section} @itemx -mdata=@var{data section} @itemx -mrodata=@var{readonly data section} +@opindex mtext +@opindex mdata +@opindex mrodata Put functions, data, and readonly data in @var{text section}, @var{data section}, and @var{readonly data section} respectively by default. This can be overridden with the @code{section} attribute. @@ -7741,29 +8449,38 @@ given below. @table @gcctabopt @item -m32032 @itemx -m32032 +@opindex m32032 +@opindex m32032 Generate output for a 32032. This is the default when the compiler is configured for 32032 and 32016 based systems. @item -m32332 @itemx -m32332 +@opindex m32332 +@opindex m32332 Generate output for a 32332. This is the default when the compiler is configured for 32332-based systems. @item -m32532 @itemx -m32532 +@opindex m32532 +@opindex m32532 Generate output for a 32532. This is the default when the compiler is configured for 32532-based systems. @item -m32081 +@opindex m32081 Generate output containing 32081 instructions for floating point. This is the default for all systems. @item -m32381 +@opindex m32381 Generate output containing 32381 instructions for floating point. This also implies @samp{-m32081}. The 32381 is only compatible with the 32332 and 32532 cpus. This is the default for the pc532-netbsd configuration. @item -mmulti-add +@opindex mmulti-add Try and generate multiply-add floating point instructions @code{polyF} and @code{dotF}. This option is only available if the @samp{-m32381} option is in effect. Using these instructions requires changes to to @@ -7772,22 +8489,27 @@ performance. This option should only be enabled when compiling code particularly likely to make heavy use of multiply-add instructions. @item -mnomulti-add +@opindex mnomulti-add Do not try and generate multiply-add floating point instructions @code{polyF} and @code{dotF}. This is the default on all platforms. @item -msoft-float +@opindex msoft-float Generate output containing library calls for floating point. @strong{Warning:} the requisite libraries may not be available. @item -mnobitfield +@opindex mnobitfield Do not use the bit-field instructions. On some machines it is faster to use shifting and masking operations. This is the default for the pc532. @item -mbitfield +@opindex mbitfield Do use the bit-field instructions. This is the default for all platforms except the pc532. @item -mrtd +@opindex mrtd Use a different function-calling convention, in which functions that take a fixed number of arguments return pop their arguments on return with the @code{ret} instruction. @@ -7809,6 +8531,7 @@ This option takes its name from the 680x0 @code{rtd} instruction. @item -mregparam +@opindex mregparam Use a different function-calling convention where the first two arguments are passed in registers. @@ -7817,26 +8540,31 @@ used on Unix, so you cannot use it if you need to call libraries compiled with the Unix compiler. @item -mnoregparam +@opindex mnoregparam Do not pass any arguments in registers. This is the default for all targets. @item -msb +@opindex msb It is OK to use the sb as an index register which is always loaded with zero. This is the default for the pc532-netbsd target. @item -mnosb +@opindex mnosb The sb register is not available for use or has not been initialized to zero by the run time system. This is the default for all targets except the pc532-netbsd. It is also implied whenever @samp{-mhimem} or @samp{-fpic} is set. @item -mhimem +@opindex mhimem Many ns32000 series addressing modes use displacements of up to 512MB. If an address is above 512MB then displacements from zero can not be used. This option causes code to be generated which can be loaded above 512MB. This may be useful for operating systems or ROM code. @item -mnohimem +@opindex mnohimem Assume code will be loaded in the first 512MB of virtual address space. This is the default for all platforms. @@ -7851,6 +8579,7 @@ These options are defined for AVR implementations: @table @gcctabopt @item -mmcu=@var{mcu} +@opindex mmcu Specify ATMEL AVR instruction set or MCU type. Instruction set avr1 is for the minimal AVR core, not supported by the C @@ -7872,24 +8601,30 @@ Instruction set avr5 is for the enhanced AVR core with up to 128K program memory space (MCU types: atmega161, atmega163, atmega32, at94k). @item -msize +@opindex msize Output instruction sizes to the asm file. @item -minit-stack=@var{N} +@opindex minit-stack Specify the initial stack address, which may be a symbol or numeric value, __stack is the default. @item -mno-interrupts +@opindex mno-interrupts Generated code is not compatible with hardware interrupts. Code size will be smaller. @item -mcall-prologues +@opindex mcall-prologues Functions prologues/epilogues expanded as call to appropriate subroutines. Code size will be smaller. @item -mno-tablejump +@opindex mno-tablejump Do not generate tablejump insns which sometimes increase code size. @item -mtiny-stack +@opindex mtiny-stack Change only the low 8 bits of the stack pointer. @end table @@ -7905,47 +8640,74 @@ processors. @item -mhardlit @itemx -mhardlit @itemx -mno-hardlit +@opindex mhardlit +@opindex mhardlit +@opindex mno-hardlit Inline constants into the code stream if it can be done in two instructions or less. @item -mdiv @itemx -mdiv @itemx -mno-div +@opindex mdiv +@opindex mdiv +@opindex mno-div Use the divide instruction. (Enabled by default). @item -mrelax-immediate @itemx -mrelax-immediate @itemx -mno-relax-immediate +@opindex mrelax-immediate +@opindex mrelax-immediate +@opindex mno-relax-immediate Allow arbitrary sized immediates in bit operations. @item -mwide-bitfields @itemx -mwide-bitfields @itemx -mno-wide-bitfields +@opindex mwide-bitfields +@opindex mwide-bitfields +@opindex mno-wide-bitfields Always treat bitfields as int-sized. @item -m4byte-functions @itemx -m4byte-functions @itemx -mno-4byte-functions +@opindex m4byte-functions +@opindex m4byte-functions +@opindex mno-4byte-functions Force all functions to be aligned to a four byte boundary. @item -mcallgraph-data @itemx -mcallgraph-data @itemx -mno-callgraph-data +@opindex mcallgraph-data +@opindex mcallgraph-data +@opindex mno-callgraph-data Emit callgraph information. @item -mslow-bytes @itemx -mslow-bytes @itemx -mno-slow-bytes +@opindex mslow-bytes +@opindex mslow-bytes +@opindex mno-slow-bytes Prefer word access when reading byte quantities. @item -mlittle-endian @itemx -mlittle-endian @itemx -mbig-endian +@opindex mlittle-endian +@opindex mlittle-endian +@opindex mbig-endian Generate code for a little endian target. @item -m210 @itemx -m210 @itemx -m340 +@opindex m210 +@opindex m210 +@opindex m340 Generate code for the 210 processor. @end table @@ -7957,66 +8719,87 @@ These are the @samp{-m} options defined for the Intel IA-64 architecture. @table @gcctabopt @item -mbig-endian +@opindex mbig-endian Generate code for a big endian target. This is the default for HPUX. @item -mlittle-endian +@opindex mlittle-endian Generate code for a little endian target. This is the default for AIX5 and Linux. @item -mgnu-as @itemx -mno-gnu-as +@opindex mgnu-as +@opindex mno-gnu-as Generate (or don't) code for the GNU assembler. This is the default. @c Also, this is the default if the configure option @samp{--with-gnu-as} @c is used. @item -mgnu-ld @itemx -mno-gnu-ld +@opindex mgnu-ld +@opindex mno-gnu-ld Generate (or don't) code for the GNU linker. This is the default. @c Also, this is the default if the configure option @samp{--with-gnu-ld} @c is used. @item -mno-pic +@opindex mno-pic Generate code that does not use a global pointer register. The result is not position independent code, and violates the IA-64 ABI. @item -mvolatile-asm-stop @itemx -mno-volatile-asm-stop +@opindex mvolatile-asm-stop +@opindex mno-volatile-asm-stop Generate (or don't) a stop bit immediately before and after volatile asm statements. @item -mb-step +@opindex mb-step Generate code that works around Itanium B step errata. @item -mregister-names @itemx -mno-register-names +@opindex mregister-names +@opindex mno-register-names Generate (or don't) @samp{in}, @samp{loc}, and @samp{out} register names for the stacked registers. This may make assembler output more readable. @item -mno-sdata @itemx -msdata +@opindex mno-sdata +@opindex msdata Disable (or enable) optimizations that use the small data section. This may be useful for working around optimizer bugs. @item -mconstant-gp +@opindex mconstant-gp Generate code that uses a single constant global pointer value. This is useful when compiling kernel code. @item -mauto-pic +@opindex mauto-pic Generate code that is self-relocatable. This implies @samp{-mconstant-gp}. This is useful when compiling firmware code. @item -minline-divide-min-latency +@opindex minline-divide-min-latency Generate code for inline divides using the minimum latency algorithm. @item -minline-divide-max-throughput +@opindex minline-divide-max-throughput Generate code for inline divides using the maximum throughput algorithm. @item -mno-dwarf2-asm @itemx -mdwarf2-asm +@opindex mno-dwarf2-asm +@opindex mdwarf2-asm Don't (or do) generate assembler code for the DWARF2 line number debugging info. This may be useful when not using the GNU assembler. @item -mfixed-range=@var{register range} +@opindex mfixed-range Generate code treating the given register range as fixed registers. A fixed register is one that the register allocator can not use. This is useful when compiling kernel code. A register range is specified as @@ -8032,14 +8815,17 @@ These @samp{-m} options are defined for D30V implementations: @table @gcctabopt @item -mextmem +@opindex mextmem Link the @samp{.text}, @samp{.data}, @samp{.bss}, @samp{.strings}, @samp{.rodata}, @samp{.rodata1}, @samp{.data1} sections into external memory, which starts at location @code{0x80000000}. @item -mextmemory +@opindex mextmemory Same as the @samp{-mextmem} switch. @item -monchip +@opindex monchip Link the @samp{.text} section into onchip text memory, which starts at location @code{0x0}. Also link @samp{.data}, @samp{.bss}, @samp{.strings}, @samp{.rodata}, @samp{.rodata1}, @samp{.data1} sections @@ -8047,16 +8833,20 @@ into onchip data memory, which starts at location @code{0x20000000}. @item -mno-asm-optimize @itemx -masm-optimize +@opindex mno-asm-optimize +@opindex masm-optimize Disable (enable) passing @samp{-O} to the assembler when optimizing. The assembler uses the @samp{-O} option to automatically parallelize adjacent short instructions where possible. @item -mbranch-cost=@var{n} +@opindex mbranch-cost Increase the internal costs of branches to @var{n}. Higher costs means that the compiler will issue more instructions to avoid doing a branch. The default is 2. @item -mcond-exec=@var{n} +@opindex mcond-exec Specify the maximum number of conditionally executed instructions that replace a branch. The default is 4. @end table @@ -8078,6 +8868,7 @@ it. @table @gcctabopt @item -fexceptions +@opindex fexceptions Enable exception handling. Generates extra code needed to propagate exceptions. For some targets, this implies GNU CC will generate frame unwind information for all functions, which can produce significant data @@ -8091,12 +8882,14 @@ disable this option if you are compiling older C++ programs that don't use exception handling. @item -funwind-tables +@opindex funwind-tables Similar to @option{-fexceptions}, except that it will just generate any needed static data, but will not affect the generated code in any other way. You will normally not enable this option; instead, a language processor that needs this handling would enable it on your behalf. @item -fpcc-struct-return +@opindex fpcc-struct-return Return ``short'' @code{struct} and @code{union} values in memory like longer ones, rather than in registers. This convention is less efficient, but it has the advantage of allowing intercallability between @@ -8109,6 +8902,7 @@ Short structures and unions are those whose size and alignment match that of some integer type. @item -freg-struct-return +@opindex freg-struct-return Use the convention that @code{struct} and @code{union} values are returned in registers when possible. This is more efficient for small structures than @samp{-fpcc-struct-return}. @@ -8121,14 +8915,17 @@ is the principal compiler. In those cases, we can choose the standard, and we chose the more efficient register return alternative. @item -fshort-enums +@opindex fshort-enums Allocate to an @code{enum} type only as many bytes as it needs for the declared range of possible values. Specifically, the @code{enum} type will be equivalent to the smallest integer type which has enough room. @item -fshort-double +@opindex fshort-double Use the same size for @code{double} as for @code{float}. @item -fshared-data +@opindex fshared-data Requests that the data and non-@code{const} variables of this compilation be shared data rather than private data. The distinction makes sense only on certain operating systems, where shared data is @@ -8136,6 +8933,7 @@ shared between processes running the same program, while private data exists in one copy per process. @item -fno-common +@opindex fno-common In C, allocate even uninitialized global variables in the data section of the object file, rather than generating them as common blocks. This has the effect that if the same variable is declared (without @code{extern}) in @@ -8144,9 +8942,11 @@ 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. @item -fno-ident +@opindex fno-ident Ignore the @samp{#ident} directive. @item -fno-gnu-linker +@opindex 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 @@ -8157,6 +8957,7 @@ distribution.) For systems which @emph{must} use @command{collect2}, the compiler driver @command{gcc} is configured to do this automatically. @item -finhibit-size-directive +@opindex finhibit-size-directive Don't output a @code{.size} assembler directive, or anything else that would cause trouble if the function is split in the middle, and the two halves are placed at locations far apart in memory. This option is @@ -8164,6 +8965,7 @@ used when compiling @file{crtstuff.c}; you should not need to use it for anything else. @item -fverbose-asm +@opindex 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 @@ -8174,17 +8976,21 @@ extra information to be omitted and is useful when comparing two assembler files. @item -fvolatile +@opindex fvolatile Consider all memory references through pointers to be volatile. @item -fvolatile-global +@opindex fvolatile-global Consider all memory references to extern and global data items to be volatile. GCC does not consider static data items to be volatile because of this switch. @item -fvolatile-static +@opindex fvolatile-static Consider all memory references to static data to be volatile. @item -fpic +@opindex fpic @cindex global offset table @cindex PIC Generate position-independent code (PIC) suitable for use in a shared @@ -8204,6 +9010,7 @@ but not for the Sun 386i. Code generated for the IBM RS/6000 is always position-independent. @item -fPIC +@opindex fPIC If supported for the target machine, emit position-independent code, suitable for dynamic linking and avoiding any limit on the size of the global offset table. This option makes a difference on the m68k, m88k, @@ -8213,6 +9020,7 @@ Position-independent code requires special support, and therefore works only on certain machines. @item -ffixed-@var{reg} +@opindex ffixed Treat the register named @var{reg} 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). @@ -8225,6 +9033,7 @@ This flag does not have a negative form, because it specifies a three-way choice. @item -fcall-used-@var{reg} +@opindex fcall-used Treat the register named @var{reg} 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 @@ -8238,6 +9047,7 @@ This flag does not have a negative form, because it specifies a three-way choice. @item -fcall-saved-@var{reg} +@opindex fcall-saved Treat the register named @var{reg} 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 @@ -8254,11 +9064,13 @@ This flag does not have a negative form, because it specifies a three-way choice. @item -fpack-struct +@opindex fpack-struct Pack all structure members together without holes. Usually you would not want to use this option, since it makes the code suboptimal, and the offsets of structure members won't agree with system libraries. @item -fcheck-memory-usage +@opindex fcheck-memory-usage Generate extra code to check each memory access. GCC will generate code that is suitable for a detector of bad memory accesses such as @file{Checker}. @@ -8298,6 +9110,7 @@ inline function, to indicate any reads, writes, or copies being done. These calls would be similar to those done in the stubs described above. @item -fprefix-function-name +@opindex fprefix-function-name Request GCC to add a prefix to the symbols generated for function names. GCC adds a prefix to the names of functions defined as well as functions called. Code compiled with this option and code compiled @@ -8326,6 +9139,7 @@ prefix_foo (int a) This option is designed to be used with @samp{-fcheck-memory-usage}. @item -finstrument-functions +@opindex finstrument-functions Generate instrumentation calls for entry and exit to functions. Just after function entry and just before function exit, the following profiling functions will be called with the address of the current @@ -8363,6 +9177,7 @@ cannot safely be called (perhaps signal handlers, if the profiling routines generate output or allocate memory). @item -fstack-check +@opindex fstack-check Generate code to verify that you do not go beyond the boundary of the stack. You should specify this flag if you are running in an environment with multiple threads, but only rarely need to specify it in @@ -8376,6 +9191,9 @@ to ensure that the operating system sees the stack being extended. @item -fstack-limit-register=@var{reg} @itemx -fstack-limit-symbol=@var{sym} @itemx -fno-stack-limit +@opindex fstack-limit-register +@opindex fstack-limit-symbol +@opindex fno-stack-limit Generate code to ensure that the stack does not grow beyond a certain value, either the value of a register or the address of a symbol. If the stack would grow beyond the value, a signal is raised. For most targets, @@ -8393,6 +9211,9 @@ limit of 128K. @item -fargument-alias @itemx -fargument-noalias @itemx -fargument-noalias-global +@opindex fargument-alias +@opindex fargument-noalias +@opindex fargument-noalias-global Specify the possible relationships among parameters and between parameters and global data. @@ -8407,6 +9228,7 @@ Each language will automatically use whatever option is required by the language standard. You should not need to use these options yourself. @item -fleading-underscore +@opindex fleading-underscore This option and its counterpart, -fno-leading-underscore, forcibly change the way C symbols are represented in the object file. One use is to help link with legacy assembly code. |