and register usage.
* Environment Variables:: Env vars that affect GCC.
* Precompiled Headers:: Compiling a header once, and using it many times.
-* Running Protoize:: Automatically adding or removing function prototypes.
@end menu
@c man begin OPTIONS
@item Overall Options
@xref{Overall Options,,Options Controlling the Kind of Output}.
@gccoptlist{-c -S -E -o @var{file} -combine -pipe -pass-exit-codes @gol
--x @var{language} -v -### --help@r{[}=@var{class}@r{]} --target-help @gol
+-x @var{language} -v -### --help@r{[}=@var{class}@r{[},@dots{}@r{]]} --target-help @gol
--version -wrapper@@@var{file}}
@item C Language Options
-Wchar-subscripts -Wclobbered -Wcomment @gol
-Wconversion -Wcoverage-mismatch -Wno-deprecated @gol
-Wno-deprecated-declarations -Wdisabled-optimization @gol
--Wdisallowed-function-list=@var{sym},@var{sym},@dots{} @gol
-Wno-div-by-zero -Wempty-body -Wenum-compare -Wno-endif-labels @gol
-Werror -Werror=* @gol
-Wfatal-errors -Wfloat-equal -Wformat -Wformat=2 @gol
-fdata-sections -fdce -fdce @gol
-fdelayed-branch -fdelete-null-pointer-checks -fdse -fdse @gol
-fearly-inlining -fexpensive-optimizations -ffast-math @gol
--ffinite-math-only -ffloat-store -fforward-propagate @gol
--ffunction-sections -fgcse -fgcse-after-reload -fgcse-las -fgcse-lm @gol
+-ffinite-math-only -ffloat-store -fexcess-precision=@var{style} @gol
+-fforward-propagate -ffunction-sections @gol
+-fgcse -fgcse-after-reload -fgcse-las -fgcse-lm @gol
-fgcse-sm -fif-conversion -fif-conversion2 -findirect-inlining @gol
-finline-functions -finline-functions-called-once -finline-limit=@var{n} @gol
-finline-small-functions -fipa-cp -fipa-cp-clone -fipa-matrix-reorg -fipa-pta @gol
@emph{DEC Alpha/VMS Options}
@gccoptlist{-mvms-return-codes}
+@emph{FR30 Options}
+@gccoptlist{-msmall-model -mno-lsim}
+
@emph{FRV Options}
@gccoptlist{-mgpr-32 -mgpr-64 -mfpr-32 -mfpr-64 @gol
-mhard-float -msoft-float @gol
-m96bit-long-double -mregparm=@var{num} -msseregparm @gol
-mveclibabi=@var{type} -mpc32 -mpc64 -mpc80 -mstackrealign @gol
-momit-leaf-frame-pointer -mno-red-zone -mno-tls-direct-seg-refs @gol
--mcmodel=@var{code-model} @gol
+-mcmodel=@var{code-model} -mabi=@var{name} @gol
-m32 -m64 -mlarge-data-threshold=@var{num} @gol
-mfused-madd -mno-fused-madd -msse2avx}
@emph{x86-64 Options}
See i386 and x86-64 Options.
+@emph{i386 and x86-64 Windows Options}
+@gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll
+-mnop-fun-dllimport -mthread -mwin32 -mwindows}
+
@emph{Xstormy16 Options}
@gccoptlist{-msim}
line options for each tool. For some targets extra target-specific
information may also be printed.
-@item --help=@var{class}@r{[},@var{qualifier}@r{]}
+@item --help=@{@var{class}@r{|[}^@r{]}@var{qualifier}@}@r{[},@dots{}@r{]}
Print (on the standard output) a description of the command line
-options understood by the compiler that fit into a specific class.
-The class can be one of @samp{optimizers}, @samp{warnings}, @samp{target},
-@samp{params}, or @var{language}:
+options understood by the compiler that fit into all specified classes
+and qualifiers. These are the supported classes:
@table @asis
@item @samp{optimizers}
This will display the options that are common to all languages.
@end table
-It is possible to further refine the output of the @option{--help=}
-option by adding a comma separated list of qualifiers after the
-class. These can be any from the following list:
+These are the supported qualifiers:
@table @asis
@item @samp{undocumented}
@end smallexample
The sense of a qualifier can be inverted by prefixing it with the
-@var{^} character, so for example to display all binary warning
+@samp{^} character, so for example to display all binary warning
options (i.e., ones that are either on or off and that do not take an
argument), which have a description the following can be used:
--help=warnings,^joined,^undocumented
@end smallexample
-A class can also be used as a qualifier, although this usually
+The argument to @option{--help=} should not consist solely of inverted
+qualifiers.
+
+Combining several classes is possible, although this usually
restricts the output by so much that there is nothing to display. One
case where it does work however is when one of the classes is
@var{target}. So for example to display all the target-specific
are enabled at @option{-O2} by using:
@smallexample
--O2 --help=optimizers
+-Q -O2 --help=optimizers
@end smallexample
Alternatively you can discover which binary optimizations are enabled
enumeration. @code{case} labels outside the enumeration range also
provoke warnings when this option is used.
-@item -Wsync-nand
+@item -Wsync-nand @r{(C and C++ only)}
@opindex Wsync-nand
@opindex Wno-sync-nand
Warn when @code{__sync_fetch_and_nand} and @code{__sync_nand_and_fetch}
@option{-funsafe-loop-optimizations} warn if the compiler made
such assumptions.
-@item -Wno-pedantic-ms-format
+@item -Wno-pedantic-ms-format @r{(MinGW targets only)}
@opindex Wno-pedantic-ms-format
@opindex Wpedantic-ms-format
Disables the warnings about non-ISO @code{printf} / @code{scanf} format
This option is implied by @option{-pedantic}, and can be disabled with
@option{-Wno-overlength-strings}.
-
-@item -Wdisallowed-function-list=@var{sym},@var{sym},@dots{}
-@opindex Wdisallowed-function-list
-
-If any of @var{sym} is called, GCC will issue a warning. This can be useful
-in enforcing coding conventions that ban calls to certain functions, for
-example, @code{alloca}, @code{malloc}, etc.
@end table
@node Debugging Options
@item -fno-merge-debug-strings
@opindex fmerge-debug-strings
@opindex fno-merge-debug-strings
-Direct the linker to merge together strings which are identical in
-different object files. This is not supported by all assemblers or
-linker. This decreases the size of the debug information in the
-output file at the cost of increasing link processing time. This is
-on by default.
+Direct the linker to not merge together strings in the debugging
+information which are identical in different object files. Merging is
+not supported by all assemblers or linkers. Merging decreases the size
+of the debug information in the output file at the cost of increasing
+link processing time. Merging is enabled by default.
@item -fdebug-prefix-map=@var{old}=@var{new}
@opindex fdebug-prefix-map
@item -fdump-rtl-compgotos
@opindex fdump-rtl-compgotos
-Dump after dumplicating the computed gotos.
+Dump after duplicating the computed gotos.
@item -fdump-rtl-ce1
@itemx -fdump-rtl-ce2
with its equivalent n-dimensional matrix, where n < m.
This reduces the level of indirection needed for accessing the elements
of the matrix. The second optimization is matrix transposing that
-attemps to change the order of the matrix's dimensions in order to
+attempts to change the order of the matrix's dimensions in order to
improve cache locality.
Both optimizations need the @option{-fwhole-program} flag.
Transposing is enabled only if profiling information is available.
point. Use @option{-ffloat-store} for such programs, after modifying
them to store all pertinent intermediate computations into variables.
+@item -fexcess-precision=@var{style}
+@opindex fexcess-precision
+This option allows further control over excess precision on machines
+where floating-point registers have more precision than the IEEE
+@code{float} and @code{double} types and the processor does not
+support operations rounding to those types. By default,
+@option{-fexcess-precision=fast} is in effect; this means that
+operations are carried out in the precision of the registers and that
+it is unpredictable when rounding to the types specified in the source
+code takes place. When compiling C, if
+@option{-fexcess-precision=standard} is specified then excess
+precision will follow the rules specified in ISO C99; in particular,
+both casts and assignments cause values to be rounded to their
+semantic types (whereas @option{-ffloat-store} only affects
+assignments). This option is enabled by default for C if a strict
+conformance option such as @option{-std=c99} is used.
+
+@opindex mfpmath
+@option{-fexcess-precision=standard} is not implemented for languages
+other than C, and has no effect if
+@option{-funsafe-math-optimizations} or @option{-ffast-math} is
+specified. On the x86, it also has no effect if @option{-mfpmath=sse}
+or @option{-mfpmath=sse+387} is specified; in the former case, IEEE
+semantics apply without excess precision, and in the latter, rounding
+is unpredictable.
+
@item -ffast-math
@opindex ffast-math
Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations},
* Darwin Options::
* DEC Alpha Options::
* DEC Alpha/VMS Options::
+* FR30 Options::
* FRV Options::
* GNU/Linux Options::
* H8/300 Options::
* HPPA Options::
* i386 and x86-64 Options::
+* i386 and x86-64 Windows Options::
* IA-64 Options::
* M32C Options::
* M32R/D Options::
the compiler generates code to handle function calls via function
pointers.
-@item -mnop-fun-dllimport
-@opindex mnop-fun-dllimport
-Disable support for the @code{dllimport} attribute.
-
@item -msingle-pic-base
@opindex msingle-pic-base
Treat the register used for PIC addressing as read-only, rather than
Schedules as an EV6 and supports the BWX, CIX, FIX, and MAX extensions.
@end table
+Native Linux/GNU toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-mcpu=native} has no effect if GCC does not recognize
+the processor.
+
@item -mtune=@var{cpu_type}
@opindex mtune
Set only the instruction scheduling parameters for machine type
@var{cpu_type}. The instruction set is not changed.
+Native Linux/GNU toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-mtune=native} has no effect if GCC does not recognize
+the processor.
+
@item -mmemory-latency=@var{time}
@opindex mmemory-latency
Sets the latency the scheduler should assume for typical memory
style condition (e.g.@: error) codes.
@end table
+@node FR30 Options
+@subsection FR30 Options
+@cindex FR30 Options
+
+These options are defined specifically for the FR30 port.
+
+@table @gcctabopt
+
+@item -msmall-model
+@opindex msmall-model
+Use the small address space model. This can produce smaller code, but
+it does assume that all symbolic values and addresses will fit into a
+20-bit range.
+
+@item -mno-lsim
+@opindex mno-lsim
+Assume that run-time support has been provided and so there is no need
+to include the simulator library (@file{libsim.a}) on the linker
+command line.
+
+@end table
+
@node FRV Options
@subsection FRV Options
@cindex FRV Options
A deprecated synonym for @option{-mtune}.
@item -mfpmath=@var{unit}
-@opindex march
+@opindex mfpmath
Generate floating point arithmetics for selected unit @var{unit}. The choices
for @var{unit} are:
@item -mrecip
@opindex mrecip
This option will enable GCC to use RCPSS and RSQRTSS instructions (and their
-vectorized variants RCPPS and RSQRTPS) with an additional Newton-Rhapson step
+vectorized variants RCPPS and RSQRTPS) with an additional Newton-Raphson step
to increase precision instead of DIVSS and SQRTSS (and their vectorized
variants) for single precision floating point arguments. These instructions
are generated only when @option{-funsafe-math-optimizations} is enabled
@option{-funsafe-math-optimizations} have to be enabled. A SVML or ACML ABI
compatible library will have to be specified at link time.
+@item -mabi=@var{name}
+@opindex mabi
+Generate code for the specified calling convention. Permissible values
+are: @samp{sysv} for the ABI used on GNU/Linux and other systems and
+@samp{ms} for the Microsoft ABI. The default is to use the Microsoft
+ABI when targeting Windows. On all other systems, the default is the
+SYSV ABI. You can control this behavior for a specific function by
+using the function attribute @samp{ms_abi}/@samp{sysv_abi}.
+@xref{Function Attributes}.
+
@item -mpush-args
@itemx -mno-push-args
@opindex mpush-args
@opindex m210
@opindex m340
Generate code for the 210 processor.
+
+@item -mno-lsim
+@opindex no-lsim
+Assume that run-time support has been provided and so omit the
+simulator library (@file{libsim.a)} from the linker command line.
+
+@item -mstack-increment=@var{size}
+@opindex mstack-increment
+Set the maximum amount for a single stack increment operation. Large
+values can increase the speed of programs which contain functions
+that need a large amount of stack space, but they can also trigger a
+segmentation fault if the stack is extended too much. The default
+value is 0x1000.
+
@end table
@node MIPS Options
compile code the same as @option{-msdata=eabi}, otherwise compile code the
same as @option{-msdata=sysv}.
-@item -msdata-data
-@opindex msdata-data
+@item -msdata=data
+@opindex msdata=data
On System V.4 and embedded PowerPC systems, put small global
data in the @samp{.sdata} section. Put small uninitialized global
data in the @samp{.sbss} section. Do not use register @code{r13}
These are listed under @xref{i386 and x86-64 Options}.
+@node i386 and x86-64 Windows Options
+@subsection i386 and x86-64 Windows Options
+@cindex i386 and x86-64 Windows Options
+
+These additional options are available for Windows targets:
+
+@table @gcctabopt
+@item -mconsole
+@opindex mconsole
+This option is available for Cygwin and MinGW targets. It
+specifies that a console application is to be generated, by
+instructing the linker to set the PE header subsystem type
+required for console applications.
+This is the default behaviour for Cygwin and MinGW targets.
+
+@item -mcygwin
+@opindex mcygwin
+This option is available for Cygwin targets. It specifies that
+the Cygwin internal interface is to be used for predefined
+preprocessor macros, C runtime libraries and related linker
+paths and options. For Cygwin targets this is the default behaviour.
+This option is deprecated and will be removed in a future release.
+
+@item -mno-cygwin
+@opindex mno-cygwin
+This option is available for Cygwin targets. It specifies that
+the MinGW internal interface is to be used instead of Cygwin's, by
+setting MinGW-related predefined macros and linker paths and default
+library options.
+This option is deprecated and will be removed in a future release.
+
+@item -mdll
+@opindex mdll
+This option is available for Cygwin and MinGW targets. It
+specifies that a DLL - a dynamic link library - is to be
+generated, enabling the selection of the required runtime
+startup object and entry point.
+
+@item -mnop-fun-dllimport
+@opindex mnop-fun-dllimport
+This option is available for Cygwin and MinGW targets. It
+specifies that the dllimport attribute should be ignored.
+
+@item -mthread
+@opindex mthread
+This option is available for MinGW targets. It specifies
+that MinGW-specific thread support is to be used.
+
+@item -mwin32
+@opindex mwin32
+This option is available for Cygwin and MinGW targets. It
+specifies that the typical Windows pre-defined macros are to
+be set in the pre-processor, but does not influence the choice
+of runtime library/startup code.
+
+@item -mwindows
+@opindex mwindows
+This option is available for Cygwin and MinGW targets. It
+specifies that a GUI application is to be generated by
+instructing the linker to set the PE header subsystem type
+appropriately.
+@end table
+
+See also under @ref{i386 and x86-64 Options} for standard options.
+
@node Xstormy16 Options
@subsection Xstormy16 Options
@cindex Xstormy16 Options
@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
-two different compilations, you will get an error when you link them.
-The only reason this might be useful is if you wish to verify that the
-program will work on other systems which always work this way.
+In C code, controls the placement of uninitialized global variables.
+Unix C compilers have traditionally permitted multiple definitions of
+such variables in different compilation units by placing the variables
+in a common block.
+This is the behavior specified by @option{-fcommon}, and is the default
+for GCC on most targets.
+On the other hand, this behavior is not required by ISO C, and on some
+targets may carry a speed or code size penalty on variable references.
+The @option{-fno-common} option specifies that the compiler should place
+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 two different compilations,
+you will get a multiple-definition error when you link them.
+In this case, you must compile with @option{-fcommon} instead.
+Compiling with @option{-fno-common} is useful on targets for which
+it provides better performance, or if you wish to verify that the
+program will work on other systems which always treat uninitialized
+variable declarations this way.
@item -fno-ident
@opindex fno-ident
behavior for the options. For instance, if you use @option{-g} to
generate the precompiled header but not when using it, you may or may
not get debugging information for routines in the precompiled header.
-
-@node Running Protoize
-@section Running Protoize
-
-The program @code{protoize} is an optional part of GCC@. You can use
-it to add prototypes to a program, thus converting the program to ISO
-C in one respect. The companion program @code{unprotoize} does the
-reverse: it removes argument types from any prototypes that are found.
-
-When you run these programs, you must specify a set of source files as
-command line arguments. The conversion programs start out by compiling
-these files to see what functions they define. The information gathered
-about a file @var{foo} is saved in a file named @file{@var{foo}.X}.
-
-After scanning comes actual conversion. The specified files are all
-eligible to be converted; any files they include (whether sources or
-just headers) are eligible as well.
-
-But not all the eligible files are converted. By default,
-@code{protoize} and @code{unprotoize} convert only source and header
-files in the current directory. You can specify additional directories
-whose files should be converted with the @option{-d @var{directory}}
-option. You can also specify particular files to exclude with the
-@option{-x @var{file}} option. A file is converted if it is eligible, its
-directory name matches one of the specified directory names, and its
-name within the directory has not been excluded.
-
-Basic conversion with @code{protoize} consists of rewriting most
-function definitions and function declarations to specify the types of
-the arguments. The only ones not rewritten are those for varargs
-functions.
-
-@code{protoize} optionally inserts prototype declarations at the
-beginning of the source file, to make them available for any calls that
-precede the function's definition. Or it can insert prototype
-declarations with block scope in the blocks where undeclared functions
-are called.
-
-Basic conversion with @code{unprotoize} consists of rewriting most
-function declarations to remove any argument types, and rewriting
-function definitions to the old-style pre-ISO form.
-
-Both conversion programs print a warning for any function declaration or
-definition that they can't convert. You can suppress these warnings
-with @option{-q}.
-
-The output from @code{protoize} or @code{unprotoize} replaces the
-original source file. The original file is renamed to a name ending
-with @samp{.save} (for DOS, the saved filename ends in @samp{.sav}
-without the original @samp{.c} suffix). If the @samp{.save} (@samp{.sav}
-for DOS) file already exists, then the source file is simply discarded.
-
-@code{protoize} and @code{unprotoize} both depend on GCC itself to
-scan the program and collect information about the functions it uses.
-So neither of these programs will work until GCC is installed.
-
-Here is a table of the options you can use with @code{protoize} and
-@code{unprotoize}. Each option works with both programs unless
-otherwise stated.
-
-@table @code
-@item -B @var{directory}
-Look for the file @file{SYSCALLS.c.X} in @var{directory}, instead of the
-usual directory (normally @file{/usr/local/lib}). This file contains
-prototype information about standard system functions. This option
-applies only to @code{protoize}.
-
-@item -c @var{compilation-options}
-Use @var{compilation-options} as the options when running @command{gcc} to
-produce the @samp{.X} files. The special option @option{-aux-info} is
-always passed in addition, to tell @command{gcc} to write a @samp{.X} file.
-
-Note that the compilation options must be given as a single argument to
-@code{protoize} or @code{unprotoize}. If you want to specify several
-@command{gcc} options, you must quote the entire set of compilation options
-to make them a single word in the shell.
-
-There are certain @command{gcc} arguments that you cannot use, because they
-would produce the wrong kind of output. These include @option{-g},
-@option{-O}, @option{-c}, @option{-S}, and @option{-o} If you include these in
-the @var{compilation-options}, they are ignored.
-
-@item -C
-Rename files to end in @samp{.C} (@samp{.cc} for DOS-based file
-systems) instead of @samp{.c}. This is convenient if you are converting
-a C program to C++. This option applies only to @code{protoize}.
-
-@item -g
-Add explicit global declarations. This means inserting explicit
-declarations at the beginning of each source file for each function
-that is called in the file and was not declared. These declarations
-precede the first function definition that contains a call to an
-undeclared function. This option applies only to @code{protoize}.
-
-@item -i @var{string}
-Indent old-style parameter declarations with the string @var{string}.
-This option applies only to @code{protoize}.
-
-@code{unprotoize} converts prototyped function definitions to old-style
-function definitions, where the arguments are declared between the
-argument list and the initial @samp{@{}. By default, @code{unprotoize}
-uses five spaces as the indentation. If you want to indent with just
-one space instead, use @option{-i " "}.
-
-@item -k
-Keep the @samp{.X} files. Normally, they are deleted after conversion
-is finished.
-
-@item -l
-Add explicit local declarations. @code{protoize} with @option{-l} inserts
-a prototype declaration for each function in each block which calls the
-function without any declaration. This option applies only to
-@code{protoize}.
-
-@item -n
-Make no real changes. This mode just prints information about the conversions
-that would have been done without @option{-n}.
-
-@item -N
-Make no @samp{.save} files. The original files are simply deleted.
-Use this option with caution.
-
-@item -p @var{program}
-Use the program @var{program} as the compiler. Normally, the name
-@file{gcc} is used.
-
-@item -q
-Work quietly. Most warnings are suppressed.
-
-@item -v
-Print the version number, just like @option{-v} for @command{gcc}.
-@end table
-
-If you need special compiler options to compile one of your program's
-source files, then you should generate that file's @samp{.X} file
-specially, by running @command{gcc} on that source file with the
-appropriate options and the option @option{-aux-info}. Then run
-@code{protoize} on the entire set of files. @code{protoize} will use
-the existing @samp{.X} file because it is newer than the source file.
-For example:
-
-@smallexample
-gcc -Dfoo=bar file1.c -aux-info file1.X
-protoize *.c
-@end smallexample
-
-@noindent
-You need to include the special files along with the rest in the
-@code{protoize} command, even though their @samp{.X} files already
-exist, because otherwise they won't get converted.
-
-@xref{Protoize Caveats}, for more information on how to use
-@code{protoize} successfully.
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