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doc: Move specs documentation to GCC internals manual [PR69367] [PR69849]
The description of specs should have ended up in the GCC internals manual instead of the user-facing documentation when the two manuals were split many years ago. gcc/ChangeLog PR driver/69367 PR driver/69849 * Makefile.in (TEXI_GCCINT_FILES): Add specs.texi. * doc/gccint.texi: Include it. * doc/install.texi: Fix cross-references. * doc/invoke.texi: Likewise. (Option Summary): Reclassify -specs/--specs as a developer option. (Overall Options): Move -specs= documentation to... (Developer Options): ...here. (Spec Files): Move entire section to.... * doc/specs.texi: ....new file. * common.opt.urls: Regenerated.
This commit is contained in:
Sandra Loosemore
@@ -3809,7 +3809,7 @@ TEXI_GCCINT_FILES = gccint.texi gcc-common.texi gcc-vers.texi \
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sourcebuild.texi gty.texi libgcc.texi cfg.texi tree-ssa.texi \
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loop.texi generic.texi gimple.texi plugins.texi optinfo.texi \
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match-and-simplify.texi analyzer.texi ux.texi poly-int.texi \
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params.texi
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params.texi specs.texi
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TEXI_GCCINSTALL_FILES = install.texi fdl.texi \
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gcc-common.texi gcc-vers.texi
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@@ -2003,10 +2003,10 @@ shared-libgcc
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UrlSuffix(gcc/Link-Options.html#index-shared-libgcc)
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specs
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UrlSuffix(gcc/Overall-Options.html#index-specs)
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UrlSuffix(gcc/Developer-Options.html#index-specs)
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specs=
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UrlSuffix(gcc/Overall-Options.html#index-specs)
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UrlSuffix(gcc/Developer-Options.html#index-specs)
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static
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UrlSuffix(gcc/Link-Options.html#index-static)
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@@ -108,6 +108,7 @@ Additional tutorial information is linked to from
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* Source Tree:: GCC source tree structure and build system.
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* Testsuites:: GCC testsuites.
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* Options:: Option specification files.
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* Spec Files:: Specifying subprocesses and the switches to pass to them.
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* Passes:: Order of passes, what they do, and what each file is for.
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* poly_int:: Representation of runtime sizes and offsets.
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* GENERIC:: Language-independent representation generated by Front Ends
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@@ -149,6 +150,7 @@ Additional tutorial information is linked to from
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@include languages.texi
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@include sourcebuild.texi
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@include options.texi
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@include specs.texi
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@include passes.texi
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@include poly-int.texi
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@include generic.texi
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@@ -986,13 +986,12 @@ This can be useful if you need to turn on a non-standard feature by
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default without modifying the compiler's source code, for instance
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@option{--with-specs=%@{!fcommon:%@{!fno-common:-fno-common@}@}}.
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@ifnothtml
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@xref{Spec Files,, Specifying subprocesses and the switches to pass to them,
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gcc, Using the GNU Compiler Collection (GCC)},
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@xref{Spec Files,, Specifying Subprocesses and the Switches to Pass to Them,
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gccint, GNU Compiler Collection (GCC) Internals}.
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@end ifnothtml
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@ifhtml
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See ``Spec Files'' in the main manual
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See ``Spec Files'' in the GCC Internals manual.
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@end ifhtml
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@end table
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@item --program-prefix=@var{prefix}
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@@ -171,7 +171,6 @@ listing and explanation of the binary and decimal byte size prefixes.
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debugging dumps.
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* Submodel Options:: Target-specific options, such as compiling for a
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specific processor variant.
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* Spec Files:: How to pass switches to sub-processes.
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* Environment Variables:: Env vars that affect GCC.
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* Precompiled Headers:: Compiling a header once, and using it many times.
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* C++ Modules:: Experimental C++20 module system.
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@@ -192,7 +191,7 @@ in the following sections.
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-dumpbase @var{dumpbase} -dumpbase-ext @var{auxdropsuf}
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-dumpdir @var{dumppfx} -x @var{language}
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-v -### --help@r{[}=@var{class}@r{[},@dots{}@r{]]} --target-help --version
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-pass-exit-codes -pipe -specs=@var{file} -wrapper
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-pass-exit-codes -pipe -wrapper
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@@@var{file} -ffile-prefix-map=@var{old}=@var{new} -fcanon-prefix-map
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-fplugin=@var{file} -fplugin-arg-@var{name}=@var{arg}
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-fdump-ada-spec@r{[}-slim@r{]} -fada-spec-parent=@var{unit}
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@@ -200,7 +199,7 @@ in the following sections.
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--assemble --compile --dumpbase @var{dumpbase}
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--dumpbase-ext @var{auxdropsuf} --dumpdir @var{dumppfx}
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--language=@var{language} --output=@var{file} --pass-exit-codes
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--pipe --preprocess --specs=@var{file} --verbose}
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--pipe --preprocess --verbose}
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@item C Language Options
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@xref{C Dialect Options,,Options Controlling C Dialect}.
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@@ -870,13 +869,14 @@ Objective-C and Objective-C++ Dialects}.
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-print-multiarch
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-print-prog-name=@var{program} -print-search-dirs -Q
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-print-sysroot -print-sysroot-headers-suffix
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-save-temps -save-temps=cwd -save-temps=obj -time@r{[}=@var{file}@r{]}
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-save-temps -save-temps=cwd -save-temps=obj
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-specs=@var{file} -time@r{[}=@var{file}@r{]}
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--dump=@var{letters}
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--print-file-name=@var{library} --print-libgcc-file-file-name
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--print-multi-directory --print-multi-lib --print-multi-os-directory
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--print-multiarch --print-prog-name=@var{program}
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--print-search-dirs --print-sysroot --print-sysroot-headers-suffix
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--save-temps
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--save-temps --specs=@var{file}
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--param @var{name}=@var{value}
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}
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@@ -2329,18 +2329,6 @@ various stages of compilation. This fails to work on some systems where
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the assembler is unable to read from a pipe; but the GNU assembler has
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no trouble.
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@opindex specs
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@item -specs=@var{file}
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@itemx --specs=@var{file}
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@itemx --specs @var{file}
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Process @var{file} after the compiler reads in the standard @file{specs}
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file, in order to override the defaults which the @command{gcc} driver
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program uses when determining what switches to pass to @command{cc1},
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@command{cc1plus}, @command{as}, @command{ld}, etc. More than one
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@option{-specs=@var{file}} can be specified on the command line, and they
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are processed in order, from left to right. @xref{Spec Files}, for
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information about the format of the @var{file}.
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@opindex wrapper
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@item -wrapper
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Invoke all subcommands under a wrapper program. The name of the
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@@ -20765,6 +20753,20 @@ Equivalent to @option{-save-temps -dumpdir @file{outdir/}}, where
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@option{-o} option is not used, the @option{-save-temps=obj} switch
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behaves like @option{-save-temps=cwd}.
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@opindex specs
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@item -specs=@var{file}
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@itemx --specs=@var{file}
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@itemx --specs @var{file}
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Process @var{file} after the compiler reads in the standard @file{specs}
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file, in order to override the defaults which the @command{gcc} driver
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program uses when determining what switches to pass to @command{cc1},
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@command{cc1plus}, @command{as}, @command{ld}, etc. More than one
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@option{-specs=@var{file}} can be specified on the command line, and they
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are processed in order, from left to right.
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@xref{Spec Files,, Specifying Subprocesses and the Switches to Pass to Them,
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gccint, GNU Compiler Collection (GCC) Internals}, for
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information about the format of the @var{file}.
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@opindex time
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@item -time@r{[}=@var{file}@r{]}
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Report the CPU time taken by each subprocess in the compilation
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@@ -20935,8 +20937,10 @@ allocation before or after interprocedural optimization.
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@item -fmultiflags
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This option enables multilib-aware @code{TFLAGS} to be used to build
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target libraries with options different from those the compiler is
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configured to use by default, through the use of specs (@pxref{Spec
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Files}) set up by compiler internals, by the target, or by builders at
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configured to use by default, through the use of specs
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(@pxref{Spec Files,, Specifying Subprocesses and the Switches to Pass to Them,
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gccint, GNU Compiler Collection (GCC) Internals})
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set up by compiler internals, by the target, or by builders at
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configure time.
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Like @code{TFLAGS}, this allows the target libraries to be built for
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@@ -21136,7 +21140,9 @@ always three numbers separated by dots, major, minor and patchlevel version.
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@opindex dumpspecs
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@item -dumpspecs
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Print the compiler's built-in specs---and don't do anything else. (This
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is used when GCC itself is being built.) @xref{Spec Files}.
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is used when GCC itself is being built.)
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@xref{Spec Files,, Specifying Subprocesses and the Switches to Pass to Them,
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gccint, GNU Compiler Collection (GCC) Internals}.
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@opindex param
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@item --param @var{name}=@var{value}
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@@ -37354,700 +37360,6 @@ These are listed under @xref{S/390 and zSeries Options}.
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@c man end
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@node Spec Files
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@section Specifying Subprocesses and the Switches to Pass to Them
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@cindex Spec Files
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@command{gcc} is a driver program. It performs its job by invoking a
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sequence of other programs to do the work of compiling, assembling and
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linking. GCC interprets its command-line parameters and uses these to
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deduce which programs it should invoke, and which command-line options
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it ought to place on their command lines. This behavior is controlled
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by @dfn{spec strings}. In most cases there is one spec string for each
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program that GCC can invoke, but a few programs have multiple spec
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strings to control their behavior. The spec strings built into GCC can
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be overridden by using the @option{-specs=} command-line switch to specify
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a spec file.
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@dfn{Spec files} are plain-text files that are used to construct spec
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strings. They consist of a sequence of directives separated by blank
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lines. The type of directive is determined by the first non-whitespace
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character on the line, which can be one of the following:
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@table @code
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@item %@var{command}
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Issues a @var{command} to the spec file processor. The commands that can
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appear here are:
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@table @code
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@cindex @code{%include}
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@item %include <@var{file}>
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Search for @var{file} and insert its text at the current point in the
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specs file.
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@cindex @code{%include_noerr}
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@item %include_noerr <@var{file}>
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Just like @samp{%include}, but do not generate an error message if the include
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file cannot be found.
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@cindex @code{%rename}
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@item %rename @var{old_name} @var{new_name}
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Rename the spec string @var{old_name} to @var{new_name}.
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@end table
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@item *[@var{spec_name}]:
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This tells the compiler to create, override or delete the named spec
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string. All lines after this directive up to the next directive or
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blank line are considered to be the text for the spec string. If this
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results in an empty string then the spec is deleted. (Or, if the
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spec did not exist, then nothing happens.) Otherwise, if the spec
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does not currently exist a new spec is created. If the spec does
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exist then its contents are overridden by the text of this
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directive, unless the first character of that text is the @samp{+}
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character, in which case the text is appended to the spec.
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@item [@var{suffix}]:
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Creates a new @samp{[@var{suffix}] spec} pair. All lines after this directive
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and up to the next directive or blank line are considered to make up the
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spec string for the indicated suffix. When the compiler encounters an
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input file with the named suffix, it processes the spec string in
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order to work out how to compile that file. For example:
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@smallexample
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.ZZ:
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z-compile -input %i
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@end smallexample
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This says that any input file whose name ends in @samp{.ZZ} should be
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passed to the program @samp{z-compile}, which should be invoked with the
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command-line switch @option{-input} and with the result of performing the
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@samp{%i} substitution. (See below.)
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As an alternative to providing a spec string, the text following a
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suffix directive can be one of the following:
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@table @code
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@item @@@var{language}
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This says that the suffix is an alias for a known @var{language}. This is
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similar to using the @option{-x} command-line switch to GCC to specify a
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language explicitly. For example:
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@smallexample
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.ZZ:
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@@c++
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@end smallexample
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Says that .ZZ files are, in fact, C++ source files.
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@item #@var{name}
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This causes an error messages saying:
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@smallexample
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@var{name} compiler not installed on this system.
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@end smallexample
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@end table
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GCC already has an extensive list of suffixes built into it.
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This directive adds an entry to the end of the list of suffixes, but
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since the list is searched from the end backwards, it is effectively
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possible to override earlier entries using this technique.
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@end table
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GCC has the following spec strings built into it. Spec files can
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override these strings or create their own. Note that individual
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targets can also add their own spec strings to this list.
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|
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@smallexample
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asm Options to pass to the assembler
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asm_final Options to pass to the assembler post-processor
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cpp Options to pass to the C preprocessor
|
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cc1 Options to pass to the C compiler
|
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cc1plus Options to pass to the C++ compiler
|
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endfile Object files to include at the end of the link
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link Options to pass to the linker
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lib Libraries to include on the command line to the linker
|
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libgcc Decides which GCC support library to pass to the linker
|
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linker Sets the name of the linker
|
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startfile Object files to include at the start of the link
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@end smallexample
|
||||
|
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Here is a small example of a spec file:
|
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|
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@smallexample
|
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%rename lib old_lib
|
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|
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*lib:
|
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--start-group -lgcc -lc -leval1 --end-group %(old_lib)
|
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@end smallexample
|
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|
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This example renames the spec called @samp{lib} to @samp{old_lib} and
|
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then overrides the previous definition of @samp{lib} with a new one.
|
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The new definition adds in some extra command-line options before
|
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including the text of the old definition.
|
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|
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@dfn{Spec strings} are a list of command-line options to be passed to their
|
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corresponding program. In addition, the spec strings can contain
|
||||
@samp{%}-prefixed sequences to substitute variable text or to
|
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conditionally insert text into the command line. Using these constructs
|
||||
it is possible to generate quite complex command lines.
|
||||
|
||||
Here is a table of all defined @samp{%}-sequences for spec
|
||||
strings. Note that spaces are not generated automatically around the
|
||||
results of expanding these sequences. Therefore you can concatenate them
|
||||
together or combine them with constant text in a single argument.
|
||||
|
||||
@table @code
|
||||
@item %%
|
||||
Substitute one @samp{%} into the program name or argument.
|
||||
|
||||
@item %"
|
||||
Substitute an empty argument.
|
||||
|
||||
@item %i
|
||||
Substitute the name of the input file being processed.
|
||||
|
||||
@item %b
|
||||
Substitute the basename for outputs related with the input file being
|
||||
processed. This is often the substring up to (and not including) the
|
||||
last period and not including the directory but, unless %w is active, it
|
||||
expands to the basename for auxiliary outputs, which may be influenced
|
||||
by an explicit output name, and by various other options that control
|
||||
how auxiliary outputs are named.
|
||||
|
||||
@item %B
|
||||
This is the same as @samp{%b}, but include the file suffix (text after
|
||||
the last period). Without %w, it expands to the basename for dump
|
||||
outputs.
|
||||
|
||||
@item %d
|
||||
Marks the argument containing or following the @samp{%d} as a
|
||||
temporary file name, so that that file is deleted if GCC exits
|
||||
successfully. Unlike @samp{%g}, this contributes no text to the
|
||||
argument.
|
||||
|
||||
@item %g@var{suffix}
|
||||
Substitute a file name that has suffix @var{suffix} and is chosen
|
||||
once per compilation, and mark the argument in the same way as
|
||||
@samp{%d}. To reduce exposure to denial-of-service attacks, the file
|
||||
name is now chosen in a way that is hard to predict even when previously
|
||||
chosen file names are known. For example, @samp{%g.s @dots{} %g.o @dots{} %g.s}
|
||||
might turn into @samp{ccUVUUAU.s ccXYAXZ12.o ccUVUUAU.s}. @var{suffix} matches
|
||||
the regexp @samp{[.A-Za-z]*} or the special string @samp{%O}, which is
|
||||
treated exactly as if @samp{%O} had been preprocessed. Previously, @samp{%g}
|
||||
was simply substituted with a file name chosen once per compilation,
|
||||
without regard to any appended suffix (which was therefore treated
|
||||
just like ordinary text), making such attacks more likely to succeed.
|
||||
|
||||
@item %u@var{suffix}
|
||||
Like @samp{%g}, but generates a new temporary file name
|
||||
each time it appears instead of once per compilation.
|
||||
|
||||
@item %U@var{suffix}
|
||||
Substitutes the last file name generated with @samp{%u@var{suffix}}, generating a
|
||||
new one if there is no such last file name. In the absence of any
|
||||
@samp{%u@var{suffix}}, this is just like @samp{%g@var{suffix}}, except they don't share
|
||||
the same suffix @emph{space}, so @samp{%g.s @dots{} %U.s @dots{} %g.s @dots{} %U.s}
|
||||
involves the generation of two distinct file names, one
|
||||
for each @samp{%g.s} and another for each @samp{%U.s}. Previously, @samp{%U} was
|
||||
simply substituted with a file name chosen for the previous @samp{%u},
|
||||
without regard to any appended suffix.
|
||||
|
||||
@item %j@var{suffix}
|
||||
Substitutes the name of the @code{HOST_BIT_BUCKET}, if any, and if it is
|
||||
writable, and if @option{-save-temps} is not used;
|
||||
otherwise, substitute the name
|
||||
of a temporary file, just like @samp{%u}. This temporary file is not
|
||||
meant for communication between processes, but rather as a junk
|
||||
disposal mechanism.
|
||||
|
||||
@item %|@var{suffix}
|
||||
@itemx %m@var{suffix}
|
||||
Like @samp{%g}, except if @option{-pipe} is in effect. In that case
|
||||
@samp{%|} substitutes a single dash and @samp{%m} substitutes nothing at
|
||||
all. These are the two most common ways to instruct a program that it
|
||||
should read from standard input or write to standard output. If you
|
||||
need something more elaborate you can use an @samp{%@{pipe:@code{X}@}}
|
||||
construct: see for example @file{gcc/fortran/lang-specs.h}.
|
||||
|
||||
@item %.@var{SUFFIX}
|
||||
Substitutes @var{.SUFFIX} for the suffixes of a matched switch's args
|
||||
when it is subsequently output with @samp{%*}. @var{SUFFIX} is
|
||||
terminated by the next space or %.
|
||||
|
||||
@item %w
|
||||
Marks the argument containing or following the @samp{%w} as the
|
||||
designated output file of this compilation. This puts the argument
|
||||
into the sequence of arguments that @samp{%o} substitutes.
|
||||
|
||||
@item %V
|
||||
Indicates that this compilation produces no output file.
|
||||
|
||||
@item %o
|
||||
Substitutes the names of all the output files, with spaces
|
||||
automatically placed around them. You should write spaces
|
||||
around the @samp{%o} as well or the results are undefined.
|
||||
@samp{%o} is for use in the specs for running the linker.
|
||||
Input files whose names have no recognized suffix are not compiled
|
||||
at all, but they are included among the output files, so they are
|
||||
linked.
|
||||
|
||||
@item %O
|
||||
Substitutes the suffix for object files. Note that this is
|
||||
handled specially when it immediately follows @samp{%g, %u, or %U},
|
||||
because of the need for those to form complete file names. The
|
||||
handling is such that @samp{%O} is treated exactly as if it had already
|
||||
been substituted, except that @samp{%g, %u, and %U} do not currently
|
||||
support additional @var{suffix} characters following @samp{%O} as they do
|
||||
following, for example, @samp{.o}.
|
||||
|
||||
@item %I
|
||||
Substitute any of @option{-iprefix} (made from @env{GCC_EXEC_PREFIX}),
|
||||
@option{-isysroot} (made from @env{TARGET_SYSTEM_ROOT}),
|
||||
@option{-isystem} (made from @env{COMPILER_PATH} and @option{-B} options)
|
||||
and @option{-imultilib} as necessary.
|
||||
|
||||
@item %s
|
||||
Current argument is the name of a library or startup file of some sort.
|
||||
Search for that file in a standard list of directories and substitute
|
||||
the full name found. The current working directory is included in the
|
||||
list of directories scanned.
|
||||
|
||||
@item %T
|
||||
Current argument is the name of a linker script. Search for that file
|
||||
in the current list of directories to scan for libraries. If the file
|
||||
is located insert a @option{--script} option into the command line
|
||||
followed by the full path name found. If the file is not found then
|
||||
generate an error message. Note: the current working directory is not
|
||||
searched.
|
||||
|
||||
@item %e@var{str}
|
||||
Print @var{str} as an error message. @var{str} is terminated by a newline.
|
||||
Use this when inconsistent options are detected.
|
||||
|
||||
@item %n@var{str}
|
||||
Print @var{str} as a notice. @var{str} is terminated by a newline.
|
||||
|
||||
@item %(@var{name})
|
||||
Substitute the contents of spec string @var{name} at this point.
|
||||
|
||||
@item %x@{@var{option}@}
|
||||
Accumulate an option for @samp{%X}.
|
||||
|
||||
@item %X
|
||||
Output the accumulated linker options specified by a @samp{%x} spec string.
|
||||
|
||||
@item %Y
|
||||
Output the accumulated assembler options specified by @option{-Wa}.
|
||||
|
||||
@item %Z
|
||||
Output the accumulated preprocessor options specified by @option{-Wp}.
|
||||
|
||||
@item %M
|
||||
Output @code{multilib_os_dir}.
|
||||
|
||||
@item %R
|
||||
Output the concatenation of @code{target_system_root} and @code{target_sysroot_suffix}.
|
||||
|
||||
@item %a
|
||||
Process the @code{asm} spec. This is used to compute the
|
||||
switches to be passed to the assembler.
|
||||
|
||||
@item %A
|
||||
Process the @code{asm_final} spec. This is a spec string for
|
||||
passing switches to an assembler post-processor, if such a program is
|
||||
needed.
|
||||
|
||||
@item %l
|
||||
Process the @code{link} spec. This is the spec for computing the
|
||||
command line passed to the linker. Typically it makes use of the
|
||||
@samp{%L %G %S %D and %E} sequences.
|
||||
|
||||
@item %D
|
||||
Dump out a @option{-L} option for each directory that GCC believes might
|
||||
contain startup files. If the target supports multilibs then the
|
||||
current multilib directory is prepended to each of these paths.
|
||||
|
||||
@item %L
|
||||
Process the @code{lib} spec. This is a spec string for deciding which
|
||||
libraries are included on the command line to the linker.
|
||||
|
||||
@item %G
|
||||
Process the @code{libgcc} spec. This is a spec string for deciding
|
||||
which GCC support library is included on the command line to the linker.
|
||||
|
||||
@item %S
|
||||
Process the @code{startfile} spec. This is a spec for deciding which
|
||||
object files are the first ones passed to the linker. Typically
|
||||
this might be a file named @file{crt0.o}.
|
||||
|
||||
@item %E
|
||||
Process the @code{endfile} spec. This is a spec string that specifies
|
||||
the last object files that are passed to the linker.
|
||||
|
||||
@item %C
|
||||
Process the @code{cpp} spec. This is used to construct the arguments
|
||||
to be passed to the C preprocessor.
|
||||
|
||||
@item %1
|
||||
Process the @code{cc1} spec. This is used to construct the options to be
|
||||
passed to the actual C compiler (@command{cc1}).
|
||||
|
||||
@item %2
|
||||
Process the @code{cc1plus} spec. This is used to construct the options to be
|
||||
passed to the actual C++ compiler (@command{cc1plus}).
|
||||
|
||||
@item %*
|
||||
Substitute the variable part of a matched option. See below.
|
||||
Note that each comma in the substituted string is replaced by
|
||||
a single space.
|
||||
|
||||
@item %<@var{S}
|
||||
Remove all occurrences of @code{-@var{S}} from the command line. Note---this
|
||||
command is position dependent. @samp{%} commands in the spec string
|
||||
before this one see @code{-@var{S}}, @samp{%} commands in the spec string
|
||||
after this one do not.
|
||||
|
||||
@item %<@var{S}*
|
||||
Similar to @samp{%<@var{S}}, but match all switches beginning with @code{-@var{S}}.
|
||||
|
||||
@item %>@var{S}
|
||||
Similar to @samp{%<@var{S}}, but keep @code{-@var{S}} in the GCC command line.
|
||||
|
||||
@item %:@var{function}(@var{args})
|
||||
Call the named function @var{function}, passing it @var{args}.
|
||||
@var{args} is first processed as a nested spec string, then split
|
||||
into an argument vector in the usual fashion. The function returns
|
||||
a string which is processed as if it had appeared literally as part
|
||||
of the current spec.
|
||||
|
||||
The following built-in spec functions are provided:
|
||||
|
||||
@table @code
|
||||
@item @code{getenv}
|
||||
The @code{getenv} spec function takes two arguments: an environment
|
||||
variable name and a string. If the environment variable is not
|
||||
defined, a fatal error is issued. Otherwise, the return value is the
|
||||
value of the environment variable concatenated with the string. For
|
||||
example, if @env{TOPDIR} is defined as @file{/path/to/top}, then:
|
||||
|
||||
@smallexample
|
||||
%:getenv(TOPDIR /include)
|
||||
@end smallexample
|
||||
|
||||
expands to @file{/path/to/top/include}.
|
||||
|
||||
@item @code{if-exists}
|
||||
The @code{if-exists} spec function takes one argument, an absolute
|
||||
pathname to a file. If the file exists, @code{if-exists} returns the
|
||||
pathname. Here is a small example of its usage:
|
||||
|
||||
@smallexample
|
||||
*startfile:
|
||||
crt0%O%s %:if-exists(crti%O%s) crtbegin%O%s
|
||||
@end smallexample
|
||||
|
||||
@item @code{if-exists-else}
|
||||
The @code{if-exists-else} spec function is similar to the @code{if-exists}
|
||||
spec function, except that it takes two arguments. The first argument is
|
||||
an absolute pathname to a file. If the file exists, @code{if-exists-else}
|
||||
returns the pathname. If it does not exist, it returns the second argument.
|
||||
This way, @code{if-exists-else} can be used to select one file or another,
|
||||
based on the existence of the first. Here is a small example of its usage:
|
||||
|
||||
@smallexample
|
||||
*startfile:
|
||||
crt0%O%s %:if-exists(crti%O%s) \
|
||||
%:if-exists-else(crtbeginT%O%s crtbegin%O%s)
|
||||
@end smallexample
|
||||
|
||||
@item @code{if-exists-then-else}
|
||||
The @code{if-exists-then-else} spec function takes at least two arguments
|
||||
and an optional third one. The first argument is an absolute pathname to a
|
||||
file. If the file exists, the function returns the second argument.
|
||||
If the file does not exist, the function returns the third argument if there
|
||||
is one, or NULL otherwise. This can be used to expand one text, or optionally
|
||||
another, based on the existence of a file. Here is a small example of its
|
||||
usage:
|
||||
|
||||
@smallexample
|
||||
-l%:if-exists-then-else(%:getenv(VSB_DIR rtnet.h) rtnet net)
|
||||
@end smallexample
|
||||
|
||||
@item @code{sanitize}
|
||||
The @code{sanitize} spec function takes no arguments. It returns non-NULL if
|
||||
any address, thread or undefined behavior sanitizers are active.
|
||||
|
||||
@smallexample
|
||||
%@{%:sanitize(address):-funwind-tables@}
|
||||
@end smallexample
|
||||
|
||||
@item @code{replace-outfile}
|
||||
The @code{replace-outfile} spec function takes two arguments. It looks for the
|
||||
first argument in the outfiles array and replaces it with the second argument. Here
|
||||
is a small example of its usage:
|
||||
|
||||
@smallexample
|
||||
%@{fgnu-runtime:%:replace-outfile(-lobjc -lobjc-gnu)@}
|
||||
@end smallexample
|
||||
|
||||
@item @code{remove-outfile}
|
||||
The @code{remove-outfile} spec function takes one argument. It looks for the
|
||||
first argument in the outfiles array and removes it. Here is a small example
|
||||
its usage:
|
||||
|
||||
@smallexample
|
||||
%:remove-outfile(-lm)
|
||||
@end smallexample
|
||||
|
||||
@item @code{version-compare}
|
||||
The @code{version-compare} spec function takes four or five arguments of the following
|
||||
form:
|
||||
|
||||
@smallexample
|
||||
<comparison-op> <arg1> [<arg2>] <switch> <result>
|
||||
@end smallexample
|
||||
|
||||
It returns @code{result} if the comparison evaluates to true, and NULL if it doesn't.
|
||||
The supported @code{comparison-op} values are:
|
||||
|
||||
@table @code
|
||||
@item >=
|
||||
True if @code{switch} is a later (or same) version than @code{arg1}
|
||||
|
||||
@item !>
|
||||
Opposite of @code{>=}
|
||||
|
||||
@item <
|
||||
True if @code{switch} is an earlier version than @code{arg1}
|
||||
|
||||
@item !<
|
||||
Opposite of @code{<}
|
||||
|
||||
@item ><
|
||||
True if @code{switch} is @code{arg1} or later, and earlier than @code{arg2}
|
||||
|
||||
@item <>
|
||||
True if @code{switch} is earlier than @code{arg1}, or is @code{arg2} or later
|
||||
@end table
|
||||
|
||||
If the @code{switch} is not present at all, the condition is false unless the first character
|
||||
of the @code{comparison-op} is @code{!}.
|
||||
|
||||
@smallexample
|
||||
%:version-compare(>= 10.3 mmacosx-version-min= -lmx)
|
||||
@end smallexample
|
||||
|
||||
The above example would add @option{-lmx} if @option{-mmacosx-version-min=10.3.9} was
|
||||
passed.
|
||||
|
||||
@item @code{include}
|
||||
The @code{include} spec function behaves much like @code{%include}, with the advantage
|
||||
that it can be nested inside a spec and thus be conditionalized. It takes one argument,
|
||||
the filename, and looks for it in the startfile path. It always returns NULL.
|
||||
|
||||
@smallexample
|
||||
%@{static-libasan|static:%:include(libsanitizer.spec)%(link_libasan)@}
|
||||
@end smallexample
|
||||
|
||||
@item @code{pass-through-libs}
|
||||
The @code{pass-through-libs} spec function takes any number of arguments. It
|
||||
finds any @option{-l} options and any non-options ending in @file{.a} (which it
|
||||
assumes are the names of linker input library archive files) and returns a
|
||||
result containing all the found arguments each prepended by
|
||||
@option{-plugin-opt=-pass-through=} and joined by spaces. This list is
|
||||
intended to be passed to the LTO linker plugin.
|
||||
|
||||
@smallexample
|
||||
%:pass-through-libs(%G %L %G)
|
||||
@end smallexample
|
||||
|
||||
@item @code{print-asm-header}
|
||||
The @code{print-asm-header} function takes no arguments and simply
|
||||
prints a banner like:
|
||||
|
||||
@smallexample
|
||||
Assembler options
|
||||
=================
|
||||
|
||||
Use "-Wa,OPTION" to pass "OPTION" to the assembler.
|
||||
@end smallexample
|
||||
|
||||
It is used to separate compiler options from assembler options
|
||||
in the @option{--target-help} output.
|
||||
|
||||
@item @code{gt}
|
||||
The @code{gt} spec function takes two or more arguments. It returns @code{""} (the
|
||||
empty string) if the second-to-last argument is greater than the last argument, and NULL
|
||||
otherwise. The following example inserts the @code{link_gomp} spec if the last
|
||||
@option{-ftree-parallelize-loops=} option given on the command line is greater than 1:
|
||||
|
||||
@smallexample
|
||||
%@{%:gt(%@{ftree-parallelize-loops=*:%*@} 1):%:include(libgomp.spec)%(link_gomp)@}
|
||||
@end smallexample
|
||||
|
||||
@item @code{debug-level-gt}
|
||||
The @code{debug-level-gt} spec function takes one argument and returns @code{""} (the
|
||||
empty string) if @code{debug_info_level} is greater than the specified number, and NULL
|
||||
otherwise.
|
||||
|
||||
@smallexample
|
||||
%@{%:debug-level-gt(0):%@{gdwarf*:--gdwarf2@}@}
|
||||
@end smallexample
|
||||
@end table
|
||||
|
||||
@item %@{@var{S}@}
|
||||
Substitutes the @code{-@var{S}} switch, if that switch is given to GCC@.
|
||||
If that switch is not specified, this substitutes nothing. Note that
|
||||
the leading dash is omitted when specifying this option, and it is
|
||||
automatically inserted if the substitution is performed. Thus the spec
|
||||
string @samp{%@{foo@}} matches the command-line option @option{-foo}
|
||||
and outputs the command-line option @option{-foo}.
|
||||
|
||||
@item %W@{@var{S}@}
|
||||
Like %@{@code{@var{S}}@} but mark last argument supplied within as a file to be
|
||||
deleted on failure.
|
||||
|
||||
@item %@@@{@var{S}@}
|
||||
Like %@{@code{@var{S}}@} but puts the result into a @code{FILE} and substitutes
|
||||
@code{@@FILE} if an @code{@@file} argument has been supplied.
|
||||
|
||||
@item %@{@var{S}*@}
|
||||
Substitutes all the switches specified to GCC whose names start
|
||||
with @code{-@var{S}}, but which also take an argument. This is used for
|
||||
switches like @option{-o}, @option{-D}, @option{-I}, etc.
|
||||
GCC considers @option{-o foo} as being
|
||||
one switch whose name starts with @samp{o}. %@{o*@} substitutes this
|
||||
text, including the space. Thus two arguments are generated.
|
||||
|
||||
@item %@{@var{S}*&@var{T}*@}
|
||||
Like %@{@code{@var{S}}*@}, but preserve order of @code{@var{S}} and @code{@var{T}} options
|
||||
(the order of @code{@var{S}} and @code{@var{T}} in the spec is not significant).
|
||||
There can be any number of ampersand-separated variables; for each the
|
||||
wild card is optional. Useful for CPP as @samp{%@{D*&U*&A*@}}.
|
||||
|
||||
@item %@{@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if the @option{-@var{S}} switch is given to GCC@.
|
||||
|
||||
@item %@{!@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if the @option{-@var{S}} switch is @emph{not} given to GCC@.
|
||||
|
||||
@item %@{@var{S}*:@var{X}@}
|
||||
Substitutes @code{@var{X}} if one or more switches whose names start with
|
||||
@code{-@var{S}} are specified to GCC@. Normally @code{@var{X}} is substituted only
|
||||
once, no matter how many such switches appeared. However, if @code{%*}
|
||||
appears somewhere in @code{@var{X}}, then @code{@var{X}} is substituted once
|
||||
for each matching switch, with the @code{%*} replaced by the part of
|
||||
that switch matching the @code{*}.
|
||||
|
||||
If @code{%*} appears as the last part of a spec sequence then a space
|
||||
is added after the end of the last substitution. If there is more
|
||||
text in the sequence, however, then a space is not generated. This
|
||||
allows the @code{%*} substitution to be used as part of a larger
|
||||
string. For example, a spec string like this:
|
||||
|
||||
@smallexample
|
||||
%@{mcu=*:--script=%*/memory.ld@}
|
||||
@end smallexample
|
||||
|
||||
@noindent
|
||||
when matching an option like @option{-mcu=newchip} produces:
|
||||
|
||||
@smallexample
|
||||
--script=newchip/memory.ld
|
||||
@end smallexample
|
||||
|
||||
@item %@{.@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if processing a file with suffix @code{@var{S}}.
|
||||
|
||||
@item %@{!.@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if @emph{not} processing a file with suffix @code{@var{S}}.
|
||||
|
||||
@item %@{,@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if processing a file for language @code{@var{S}}.
|
||||
|
||||
@item %@{!,@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if not processing a file for language @code{@var{S}}.
|
||||
|
||||
@item %@{@var{S}|@var{P}:@var{X}@}
|
||||
Substitutes @code{@var{X}} if either @code{-@var{S}} or @code{-@var{P}} is given to
|
||||
GCC@. This may be combined with @samp{!}, @samp{.}, @samp{,}, and
|
||||
@code{*} sequences as well, although they have a stronger binding than
|
||||
the @samp{|}. If @code{%*} appears in @code{@var{X}}, all of the
|
||||
alternatives must be starred, and only the first matching alternative
|
||||
is substituted.
|
||||
|
||||
For example, a spec string like this:
|
||||
|
||||
@smallexample
|
||||
%@{.c:-foo@} %@{!.c:-bar@} %@{.c|d:-baz@} %@{!.c|d:-boggle@}
|
||||
@end smallexample
|
||||
|
||||
@noindent
|
||||
outputs the following command-line options from the following input
|
||||
command-line options:
|
||||
|
||||
@smallexample
|
||||
fred.c -foo -baz
|
||||
jim.d -bar -boggle
|
||||
-d fred.c -foo -baz -boggle
|
||||
-d jim.d -bar -baz -boggle
|
||||
@end smallexample
|
||||
|
||||
@item %@{%:@var{function}(@var{args}):@var{X}@}
|
||||
|
||||
Call function named @var{function} with args @var{args}. If the
|
||||
function returns non-NULL, then @code{@var{X}} is substituted, if it returns
|
||||
NULL, it isn't substituted.
|
||||
|
||||
@item %@{@var{S}:@var{X}; @var{T}:@var{Y}; :@var{D}@}
|
||||
|
||||
If @code{@var{S}} is given to GCC, substitutes @code{@var{X}}; else if @code{@var{T}} is
|
||||
given to GCC, substitutes @code{@var{Y}}; else substitutes @code{@var{D}}. There can
|
||||
be as many clauses as you need. This may be combined with @code{.},
|
||||
@code{,}, @code{!}, @code{|}, and @code{*} as needed.
|
||||
|
||||
|
||||
@end table
|
||||
|
||||
The switch matching text @code{@var{S}} in a @samp{%@{@var{S}@}}, @samp{%@{@var{S}:@var{X}@}}
|
||||
or similar construct can use a backslash to ignore the special meaning
|
||||
of the character following it, thus allowing literal matching of a
|
||||
character that is otherwise specially treated. For example,
|
||||
@samp{%@{std=iso9899\:1999:@var{X}@}} substitutes @code{@var{X}} if the
|
||||
@option{-std=iso9899:1999} option is given.
|
||||
|
||||
The conditional text @code{@var{X}} in a @samp{%@{@var{S}:@var{X}@}} or similar
|
||||
construct may contain other nested @samp{%} constructs or spaces, or
|
||||
even newlines. They are processed as usual, as described above.
|
||||
Trailing white space in @code{@var{X}} is ignored. White space may also
|
||||
appear anywhere on the left side of the colon in these constructs,
|
||||
except between @code{.} or @code{*} and the corresponding word.
|
||||
|
||||
The @option{-O}, @option{-f}, @option{-m}, and @option{-W} switches are
|
||||
handled specifically in these constructs. If another value of
|
||||
@option{-O} or the negated form of a @option{-f}, @option{-m}, or
|
||||
@option{-W} switch is found later in the command line, the earlier
|
||||
switch value is ignored, except with @{@code{@var{S}}*@} where @code{@var{S}} is
|
||||
just one letter, which passes all matching options.
|
||||
|
||||
The character @samp{|} at the beginning of the predicate text is used to
|
||||
indicate that a command should be piped to the following command, but
|
||||
only if @option{-pipe} is specified.
|
||||
|
||||
It is built into GCC which switches take arguments and which do not.
|
||||
(You might think it would be useful to generalize this to allow each
|
||||
compiler's spec to say which switches take arguments. But this cannot
|
||||
be done in a consistent fashion. GCC cannot even decide which input
|
||||
files have been specified without knowing which switches take arguments,
|
||||
and it must know which input files to compile in order to tell which
|
||||
compilers to run).
|
||||
|
||||
GCC also knows implicitly that arguments starting in @option{-l} are to be
|
||||
treated as compiler output files, and passed to the linker in their
|
||||
proper position among the other output files.
|
||||
|
||||
@node Environment Variables
|
||||
@section Environment Variables Affecting GCC
|
||||
@cindex environment variables
|
||||
|
||||
693
gcc/doc/specs.texi
Normal file
693
gcc/doc/specs.texi
Normal file
@@ -0,0 +1,693 @@
|
||||
@node Spec Files
|
||||
@chapter Specifying Subprocesses and the Switches to Pass to Them
|
||||
@cindex Spec Files
|
||||
|
||||
@command{gcc} is a driver program. It performs its job by invoking a
|
||||
sequence of other programs to do the work of compiling, assembling and
|
||||
linking. GCC interprets its command-line parameters and uses these to
|
||||
deduce which programs it should invoke, and which command-line options
|
||||
it ought to place on their command lines. This behavior is controlled
|
||||
by @dfn{spec strings}. In most cases there is one spec string for each
|
||||
program that GCC can invoke, but a few programs have multiple spec
|
||||
strings to control their behavior. The spec strings built into GCC can
|
||||
be overridden by using the @option{-specs=} command-line switch to specify
|
||||
a spec file.
|
||||
|
||||
@dfn{Spec files} are plain-text files that are used to construct spec
|
||||
strings. They consist of a sequence of directives separated by blank
|
||||
lines. The type of directive is determined by the first non-whitespace
|
||||
character on the line, which can be one of the following:
|
||||
|
||||
@table @code
|
||||
@item %@var{command}
|
||||
Issues a @var{command} to the spec file processor. The commands that can
|
||||
appear here are:
|
||||
|
||||
@table @code
|
||||
@cindex @code{%include}
|
||||
@item %include <@var{file}>
|
||||
Search for @var{file} and insert its text at the current point in the
|
||||
specs file.
|
||||
|
||||
@cindex @code{%include_noerr}
|
||||
@item %include_noerr <@var{file}>
|
||||
Just like @samp{%include}, but do not generate an error message if the include
|
||||
file cannot be found.
|
||||
|
||||
@cindex @code{%rename}
|
||||
@item %rename @var{old_name} @var{new_name}
|
||||
Rename the spec string @var{old_name} to @var{new_name}.
|
||||
|
||||
@end table
|
||||
|
||||
@item *[@var{spec_name}]:
|
||||
This tells the compiler to create, override or delete the named spec
|
||||
string. All lines after this directive up to the next directive or
|
||||
blank line are considered to be the text for the spec string. If this
|
||||
results in an empty string then the spec is deleted. (Or, if the
|
||||
spec did not exist, then nothing happens.) Otherwise, if the spec
|
||||
does not currently exist a new spec is created. If the spec does
|
||||
exist then its contents are overridden by the text of this
|
||||
directive, unless the first character of that text is the @samp{+}
|
||||
character, in which case the text is appended to the spec.
|
||||
|
||||
@item [@var{suffix}]:
|
||||
Creates a new @samp{[@var{suffix}] spec} pair. All lines after this directive
|
||||
and up to the next directive or blank line are considered to make up the
|
||||
spec string for the indicated suffix. When the compiler encounters an
|
||||
input file with the named suffix, it processes the spec string in
|
||||
order to work out how to compile that file. For example:
|
||||
|
||||
@smallexample
|
||||
.ZZ:
|
||||
z-compile -input %i
|
||||
@end smallexample
|
||||
|
||||
This says that any input file whose name ends in @samp{.ZZ} should be
|
||||
passed to the program @samp{z-compile}, which should be invoked with the
|
||||
command-line switch @option{-input} and with the result of performing the
|
||||
@samp{%i} substitution. (See below.)
|
||||
|
||||
As an alternative to providing a spec string, the text following a
|
||||
suffix directive can be one of the following:
|
||||
|
||||
@table @code
|
||||
@item @@@var{language}
|
||||
This says that the suffix is an alias for a known @var{language}. This is
|
||||
similar to using the @option{-x} command-line switch to GCC to specify a
|
||||
language explicitly. For example:
|
||||
|
||||
@smallexample
|
||||
.ZZ:
|
||||
@@c++
|
||||
@end smallexample
|
||||
|
||||
Says that .ZZ files are, in fact, C++ source files.
|
||||
|
||||
@item #@var{name}
|
||||
This causes an error messages saying:
|
||||
|
||||
@smallexample
|
||||
@var{name} compiler not installed on this system.
|
||||
@end smallexample
|
||||
@end table
|
||||
|
||||
GCC already has an extensive list of suffixes built into it.
|
||||
This directive adds an entry to the end of the list of suffixes, but
|
||||
since the list is searched from the end backwards, it is effectively
|
||||
possible to override earlier entries using this technique.
|
||||
|
||||
@end table
|
||||
|
||||
GCC has the following spec strings built into it. Spec files can
|
||||
override these strings or create their own. Note that individual
|
||||
targets can also add their own spec strings to this list.
|
||||
|
||||
@smallexample
|
||||
asm Options to pass to the assembler
|
||||
asm_final Options to pass to the assembler post-processor
|
||||
cpp Options to pass to the C preprocessor
|
||||
cc1 Options to pass to the C compiler
|
||||
cc1plus Options to pass to the C++ compiler
|
||||
endfile Object files to include at the end of the link
|
||||
link Options to pass to the linker
|
||||
lib Libraries to include on the command line to the linker
|
||||
libgcc Decides which GCC support library to pass to the linker
|
||||
linker Sets the name of the linker
|
||||
startfile Object files to include at the start of the link
|
||||
@end smallexample
|
||||
|
||||
Here is a small example of a spec file:
|
||||
|
||||
@smallexample
|
||||
%rename lib old_lib
|
||||
|
||||
*lib:
|
||||
--start-group -lgcc -lc -leval1 --end-group %(old_lib)
|
||||
@end smallexample
|
||||
|
||||
This example renames the spec called @samp{lib} to @samp{old_lib} and
|
||||
then overrides the previous definition of @samp{lib} with a new one.
|
||||
The new definition adds in some extra command-line options before
|
||||
including the text of the old definition.
|
||||
|
||||
@dfn{Spec strings} are a list of command-line options to be passed to their
|
||||
corresponding program. In addition, the spec strings can contain
|
||||
@samp{%}-prefixed sequences to substitute variable text or to
|
||||
conditionally insert text into the command line. Using these constructs
|
||||
it is possible to generate quite complex command lines.
|
||||
|
||||
Here is a table of all defined @samp{%}-sequences for spec
|
||||
strings. Note that spaces are not generated automatically around the
|
||||
results of expanding these sequences. Therefore you can concatenate them
|
||||
together or combine them with constant text in a single argument.
|
||||
|
||||
@table @code
|
||||
@item %%
|
||||
Substitute one @samp{%} into the program name or argument.
|
||||
|
||||
@item %"
|
||||
Substitute an empty argument.
|
||||
|
||||
@item %i
|
||||
Substitute the name of the input file being processed.
|
||||
|
||||
@item %b
|
||||
Substitute the basename for outputs related with the input file being
|
||||
processed. This is often the substring up to (and not including) the
|
||||
last period and not including the directory but, unless %w is active, it
|
||||
expands to the basename for auxiliary outputs, which may be influenced
|
||||
by an explicit output name, and by various other options that control
|
||||
how auxiliary outputs are named.
|
||||
|
||||
@item %B
|
||||
This is the same as @samp{%b}, but include the file suffix (text after
|
||||
the last period). Without %w, it expands to the basename for dump
|
||||
outputs.
|
||||
|
||||
@item %d
|
||||
Marks the argument containing or following the @samp{%d} as a
|
||||
temporary file name, so that that file is deleted if GCC exits
|
||||
successfully. Unlike @samp{%g}, this contributes no text to the
|
||||
argument.
|
||||
|
||||
@item %g@var{suffix}
|
||||
Substitute a file name that has suffix @var{suffix} and is chosen
|
||||
once per compilation, and mark the argument in the same way as
|
||||
@samp{%d}. To reduce exposure to denial-of-service attacks, the file
|
||||
name is now chosen in a way that is hard to predict even when previously
|
||||
chosen file names are known. For example, @samp{%g.s @dots{} %g.o @dots{} %g.s}
|
||||
might turn into @samp{ccUVUUAU.s ccXYAXZ12.o ccUVUUAU.s}. @var{suffix} matches
|
||||
the regexp @samp{[.A-Za-z]*} or the special string @samp{%O}, which is
|
||||
treated exactly as if @samp{%O} had been preprocessed. Previously, @samp{%g}
|
||||
was simply substituted with a file name chosen once per compilation,
|
||||
without regard to any appended suffix (which was therefore treated
|
||||
just like ordinary text), making such attacks more likely to succeed.
|
||||
|
||||
@item %u@var{suffix}
|
||||
Like @samp{%g}, but generates a new temporary file name
|
||||
each time it appears instead of once per compilation.
|
||||
|
||||
@item %U@var{suffix}
|
||||
Substitutes the last file name generated with @samp{%u@var{suffix}}, generating a
|
||||
new one if there is no such last file name. In the absence of any
|
||||
@samp{%u@var{suffix}}, this is just like @samp{%g@var{suffix}}, except they don't share
|
||||
the same suffix @emph{space}, so @samp{%g.s @dots{} %U.s @dots{} %g.s @dots{} %U.s}
|
||||
involves the generation of two distinct file names, one
|
||||
for each @samp{%g.s} and another for each @samp{%U.s}. Previously, @samp{%U} was
|
||||
simply substituted with a file name chosen for the previous @samp{%u},
|
||||
without regard to any appended suffix.
|
||||
|
||||
@item %j@var{suffix}
|
||||
Substitutes the name of the @code{HOST_BIT_BUCKET}, if any, and if it is
|
||||
writable, and if @option{-save-temps} is not used;
|
||||
otherwise, substitute the name
|
||||
of a temporary file, just like @samp{%u}. This temporary file is not
|
||||
meant for communication between processes, but rather as a junk
|
||||
disposal mechanism.
|
||||
|
||||
@item %|@var{suffix}
|
||||
@itemx %m@var{suffix}
|
||||
Like @samp{%g}, except if @option{-pipe} is in effect. In that case
|
||||
@samp{%|} substitutes a single dash and @samp{%m} substitutes nothing at
|
||||
all. These are the two most common ways to instruct a program that it
|
||||
should read from standard input or write to standard output. If you
|
||||
need something more elaborate you can use an @samp{%@{pipe:@code{X}@}}
|
||||
construct: see for example @file{gcc/fortran/lang-specs.h}.
|
||||
|
||||
@item %.@var{SUFFIX}
|
||||
Substitutes @var{.SUFFIX} for the suffixes of a matched switch's args
|
||||
when it is subsequently output with @samp{%*}. @var{SUFFIX} is
|
||||
terminated by the next space or %.
|
||||
|
||||
@item %w
|
||||
Marks the argument containing or following the @samp{%w} as the
|
||||
designated output file of this compilation. This puts the argument
|
||||
into the sequence of arguments that @samp{%o} substitutes.
|
||||
|
||||
@item %V
|
||||
Indicates that this compilation produces no output file.
|
||||
|
||||
@item %o
|
||||
Substitutes the names of all the output files, with spaces
|
||||
automatically placed around them. You should write spaces
|
||||
around the @samp{%o} as well or the results are undefined.
|
||||
@samp{%o} is for use in the specs for running the linker.
|
||||
Input files whose names have no recognized suffix are not compiled
|
||||
at all, but they are included among the output files, so they are
|
||||
linked.
|
||||
|
||||
@item %O
|
||||
Substitutes the suffix for object files. Note that this is
|
||||
handled specially when it immediately follows @samp{%g, %u, or %U},
|
||||
because of the need for those to form complete file names. The
|
||||
handling is such that @samp{%O} is treated exactly as if it had already
|
||||
been substituted, except that @samp{%g, %u, and %U} do not currently
|
||||
support additional @var{suffix} characters following @samp{%O} as they do
|
||||
following, for example, @samp{.o}.
|
||||
|
||||
@item %I
|
||||
Substitute any of @option{-iprefix} (made from @env{GCC_EXEC_PREFIX}),
|
||||
@option{-isysroot} (made from @env{TARGET_SYSTEM_ROOT}),
|
||||
@option{-isystem} (made from @env{COMPILER_PATH} and @option{-B} options)
|
||||
and @option{-imultilib} as necessary.
|
||||
|
||||
@item %s
|
||||
Current argument is the name of a library or startup file of some sort.
|
||||
Search for that file in a standard list of directories and substitute
|
||||
the full name found. The current working directory is included in the
|
||||
list of directories scanned.
|
||||
|
||||
@item %T
|
||||
Current argument is the name of a linker script. Search for that file
|
||||
in the current list of directories to scan for libraries. If the file
|
||||
is located insert a @option{--script} option into the command line
|
||||
followed by the full path name found. If the file is not found then
|
||||
generate an error message. Note: the current working directory is not
|
||||
searched.
|
||||
|
||||
@item %e@var{str}
|
||||
Print @var{str} as an error message. @var{str} is terminated by a newline.
|
||||
Use this when inconsistent options are detected.
|
||||
|
||||
@item %n@var{str}
|
||||
Print @var{str} as a notice. @var{str} is terminated by a newline.
|
||||
|
||||
@item %(@var{name})
|
||||
Substitute the contents of spec string @var{name} at this point.
|
||||
|
||||
@item %x@{@var{option}@}
|
||||
Accumulate an option for @samp{%X}.
|
||||
|
||||
@item %X
|
||||
Output the accumulated linker options specified by a @samp{%x} spec string.
|
||||
|
||||
@item %Y
|
||||
Output the accumulated assembler options specified by @option{-Wa}.
|
||||
|
||||
@item %Z
|
||||
Output the accumulated preprocessor options specified by @option{-Wp}.
|
||||
|
||||
@item %M
|
||||
Output @code{multilib_os_dir}.
|
||||
|
||||
@item %R
|
||||
Output the concatenation of @code{target_system_root} and @code{target_sysroot_suffix}.
|
||||
|
||||
@item %a
|
||||
Process the @code{asm} spec. This is used to compute the
|
||||
switches to be passed to the assembler.
|
||||
|
||||
@item %A
|
||||
Process the @code{asm_final} spec. This is a spec string for
|
||||
passing switches to an assembler post-processor, if such a program is
|
||||
needed.
|
||||
|
||||
@item %l
|
||||
Process the @code{link} spec. This is the spec for computing the
|
||||
command line passed to the linker. Typically it makes use of the
|
||||
@samp{%L %G %S %D and %E} sequences.
|
||||
|
||||
@item %D
|
||||
Dump out a @option{-L} option for each directory that GCC believes might
|
||||
contain startup files. If the target supports multilibs then the
|
||||
current multilib directory is prepended to each of these paths.
|
||||
|
||||
@item %L
|
||||
Process the @code{lib} spec. This is a spec string for deciding which
|
||||
libraries are included on the command line to the linker.
|
||||
|
||||
@item %G
|
||||
Process the @code{libgcc} spec. This is a spec string for deciding
|
||||
which GCC support library is included on the command line to the linker.
|
||||
|
||||
@item %S
|
||||
Process the @code{startfile} spec. This is a spec for deciding which
|
||||
object files are the first ones passed to the linker. Typically
|
||||
this might be a file named @file{crt0.o}.
|
||||
|
||||
@item %E
|
||||
Process the @code{endfile} spec. This is a spec string that specifies
|
||||
the last object files that are passed to the linker.
|
||||
|
||||
@item %C
|
||||
Process the @code{cpp} spec. This is used to construct the arguments
|
||||
to be passed to the C preprocessor.
|
||||
|
||||
@item %1
|
||||
Process the @code{cc1} spec. This is used to construct the options to be
|
||||
passed to the actual C compiler (@command{cc1}).
|
||||
|
||||
@item %2
|
||||
Process the @code{cc1plus} spec. This is used to construct the options to be
|
||||
passed to the actual C++ compiler (@command{cc1plus}).
|
||||
|
||||
@item %*
|
||||
Substitute the variable part of a matched option. See below.
|
||||
Note that each comma in the substituted string is replaced by
|
||||
a single space.
|
||||
|
||||
@item %<@var{S}
|
||||
Remove all occurrences of @code{-@var{S}} from the command line. Note---this
|
||||
command is position dependent. @samp{%} commands in the spec string
|
||||
before this one see @code{-@var{S}}, @samp{%} commands in the spec string
|
||||
after this one do not.
|
||||
|
||||
@item %<@var{S}*
|
||||
Similar to @samp{%<@var{S}}, but match all switches beginning with @code{-@var{S}}.
|
||||
|
||||
@item %>@var{S}
|
||||
Similar to @samp{%<@var{S}}, but keep @code{-@var{S}} in the GCC command line.
|
||||
|
||||
@item %:@var{function}(@var{args})
|
||||
Call the named function @var{function}, passing it @var{args}.
|
||||
@var{args} is first processed as a nested spec string, then split
|
||||
into an argument vector in the usual fashion. The function returns
|
||||
a string which is processed as if it had appeared literally as part
|
||||
of the current spec.
|
||||
|
||||
The following built-in spec functions are provided:
|
||||
|
||||
@table @code
|
||||
@item @code{getenv}
|
||||
The @code{getenv} spec function takes two arguments: an environment
|
||||
variable name and a string. If the environment variable is not
|
||||
defined, a fatal error is issued. Otherwise, the return value is the
|
||||
value of the environment variable concatenated with the string. For
|
||||
example, if @env{TOPDIR} is defined as @file{/path/to/top}, then:
|
||||
|
||||
@smallexample
|
||||
%:getenv(TOPDIR /include)
|
||||
@end smallexample
|
||||
|
||||
expands to @file{/path/to/top/include}.
|
||||
|
||||
@item @code{if-exists}
|
||||
The @code{if-exists} spec function takes one argument, an absolute
|
||||
pathname to a file. If the file exists, @code{if-exists} returns the
|
||||
pathname. Here is a small example of its usage:
|
||||
|
||||
@smallexample
|
||||
*startfile:
|
||||
crt0%O%s %:if-exists(crti%O%s) crtbegin%O%s
|
||||
@end smallexample
|
||||
|
||||
@item @code{if-exists-else}
|
||||
The @code{if-exists-else} spec function is similar to the @code{if-exists}
|
||||
spec function, except that it takes two arguments. The first argument is
|
||||
an absolute pathname to a file. If the file exists, @code{if-exists-else}
|
||||
returns the pathname. If it does not exist, it returns the second argument.
|
||||
This way, @code{if-exists-else} can be used to select one file or another,
|
||||
based on the existence of the first. Here is a small example of its usage:
|
||||
|
||||
@smallexample
|
||||
*startfile:
|
||||
crt0%O%s %:if-exists(crti%O%s) \
|
||||
%:if-exists-else(crtbeginT%O%s crtbegin%O%s)
|
||||
@end smallexample
|
||||
|
||||
@item @code{if-exists-then-else}
|
||||
The @code{if-exists-then-else} spec function takes at least two arguments
|
||||
and an optional third one. The first argument is an absolute pathname to a
|
||||
file. If the file exists, the function returns the second argument.
|
||||
If the file does not exist, the function returns the third argument if there
|
||||
is one, or NULL otherwise. This can be used to expand one text, or optionally
|
||||
another, based on the existence of a file. Here is a small example of its
|
||||
usage:
|
||||
|
||||
@smallexample
|
||||
-l%:if-exists-then-else(%:getenv(VSB_DIR rtnet.h) rtnet net)
|
||||
@end smallexample
|
||||
|
||||
@item @code{sanitize}
|
||||
The @code{sanitize} spec function takes no arguments. It returns non-NULL if
|
||||
any address, thread or undefined behavior sanitizers are active.
|
||||
|
||||
@smallexample
|
||||
%@{%:sanitize(address):-funwind-tables@}
|
||||
@end smallexample
|
||||
|
||||
@item @code{replace-outfile}
|
||||
The @code{replace-outfile} spec function takes two arguments. It looks for the
|
||||
first argument in the outfiles array and replaces it with the second argument. Here
|
||||
is a small example of its usage:
|
||||
|
||||
@smallexample
|
||||
%@{fgnu-runtime:%:replace-outfile(-lobjc -lobjc-gnu)@}
|
||||
@end smallexample
|
||||
|
||||
@item @code{remove-outfile}
|
||||
The @code{remove-outfile} spec function takes one argument. It looks for the
|
||||
first argument in the outfiles array and removes it. Here is a small example
|
||||
its usage:
|
||||
|
||||
@smallexample
|
||||
%:remove-outfile(-lm)
|
||||
@end smallexample
|
||||
|
||||
@item @code{version-compare}
|
||||
The @code{version-compare} spec function takes four or five arguments of the following
|
||||
form:
|
||||
|
||||
@smallexample
|
||||
<comparison-op> <arg1> [<arg2>] <switch> <result>
|
||||
@end smallexample
|
||||
|
||||
It returns @code{result} if the comparison evaluates to true, and NULL if it doesn't.
|
||||
The supported @code{comparison-op} values are:
|
||||
|
||||
@table @code
|
||||
@item >=
|
||||
True if @code{switch} is a later (or same) version than @code{arg1}
|
||||
|
||||
@item !>
|
||||
Opposite of @code{>=}
|
||||
|
||||
@item <
|
||||
True if @code{switch} is an earlier version than @code{arg1}
|
||||
|
||||
@item !<
|
||||
Opposite of @code{<}
|
||||
|
||||
@item ><
|
||||
True if @code{switch} is @code{arg1} or later, and earlier than @code{arg2}
|
||||
|
||||
@item <>
|
||||
True if @code{switch} is earlier than @code{arg1}, or is @code{arg2} or later
|
||||
@end table
|
||||
|
||||
If the @code{switch} is not present at all, the condition is false unless the first character
|
||||
of the @code{comparison-op} is @code{!}.
|
||||
|
||||
@smallexample
|
||||
%:version-compare(>= 10.3 mmacosx-version-min= -lmx)
|
||||
@end smallexample
|
||||
|
||||
The above example would add @option{-lmx} if @option{-mmacosx-version-min=10.3.9} was
|
||||
passed.
|
||||
|
||||
@item @code{include}
|
||||
The @code{include} spec function behaves much like @code{%include}, with the advantage
|
||||
that it can be nested inside a spec and thus be conditionalized. It takes one argument,
|
||||
the filename, and looks for it in the startfile path. It always returns NULL.
|
||||
|
||||
@smallexample
|
||||
%@{static-libasan|static:%:include(libsanitizer.spec)%(link_libasan)@}
|
||||
@end smallexample
|
||||
|
||||
@item @code{pass-through-libs}
|
||||
The @code{pass-through-libs} spec function takes any number of arguments. It
|
||||
finds any @option{-l} options and any non-options ending in @file{.a} (which it
|
||||
assumes are the names of linker input library archive files) and returns a
|
||||
result containing all the found arguments each prepended by
|
||||
@option{-plugin-opt=-pass-through=} and joined by spaces. This list is
|
||||
intended to be passed to the LTO linker plugin.
|
||||
|
||||
@smallexample
|
||||
%:pass-through-libs(%G %L %G)
|
||||
@end smallexample
|
||||
|
||||
@item @code{print-asm-header}
|
||||
The @code{print-asm-header} function takes no arguments and simply
|
||||
prints a banner like:
|
||||
|
||||
@smallexample
|
||||
Assembler options
|
||||
=================
|
||||
|
||||
Use "-Wa,OPTION" to pass "OPTION" to the assembler.
|
||||
@end smallexample
|
||||
|
||||
It is used to separate compiler options from assembler options
|
||||
in the @option{--target-help} output.
|
||||
|
||||
@item @code{gt}
|
||||
The @code{gt} spec function takes two or more arguments. It returns @code{""} (the
|
||||
empty string) if the second-to-last argument is greater than the last argument, and NULL
|
||||
otherwise. The following example inserts the @code{link_gomp} spec if the last
|
||||
@option{-ftree-parallelize-loops=} option given on the command line is greater than 1:
|
||||
|
||||
@smallexample
|
||||
%@{%:gt(%@{ftree-parallelize-loops=*:%*@} 1):%:include(libgomp.spec)%(link_gomp)@}
|
||||
@end smallexample
|
||||
|
||||
@item @code{debug-level-gt}
|
||||
The @code{debug-level-gt} spec function takes one argument and returns @code{""} (the
|
||||
empty string) if @code{debug_info_level} is greater than the specified number, and NULL
|
||||
otherwise.
|
||||
|
||||
@smallexample
|
||||
%@{%:debug-level-gt(0):%@{gdwarf*:--gdwarf2@}@}
|
||||
@end smallexample
|
||||
@end table
|
||||
|
||||
@item %@{@var{S}@}
|
||||
Substitutes the @code{-@var{S}} switch, if that switch is given to GCC@.
|
||||
If that switch is not specified, this substitutes nothing. Note that
|
||||
the leading dash is omitted when specifying this option, and it is
|
||||
automatically inserted if the substitution is performed. Thus the spec
|
||||
string @samp{%@{foo@}} matches the command-line option @option{-foo}
|
||||
and outputs the command-line option @option{-foo}.
|
||||
|
||||
@item %W@{@var{S}@}
|
||||
Like %@{@code{@var{S}}@} but mark last argument supplied within as a file to be
|
||||
deleted on failure.
|
||||
|
||||
@item %@@@{@var{S}@}
|
||||
Like %@{@code{@var{S}}@} but puts the result into a @code{FILE} and substitutes
|
||||
@code{@@FILE} if an @code{@@file} argument has been supplied.
|
||||
|
||||
@item %@{@var{S}*@}
|
||||
Substitutes all the switches specified to GCC whose names start
|
||||
with @code{-@var{S}}, but which also take an argument. This is used for
|
||||
switches like @option{-o}, @option{-D}, @option{-I}, etc.
|
||||
GCC considers @option{-o foo} as being
|
||||
one switch whose name starts with @samp{o}. %@{o*@} substitutes this
|
||||
text, including the space. Thus two arguments are generated.
|
||||
|
||||
@item %@{@var{S}*&@var{T}*@}
|
||||
Like %@{@code{@var{S}}*@}, but preserve order of @code{@var{S}} and @code{@var{T}} options
|
||||
(the order of @code{@var{S}} and @code{@var{T}} in the spec is not significant).
|
||||
There can be any number of ampersand-separated variables; for each the
|
||||
wild card is optional. Useful for CPP as @samp{%@{D*&U*&A*@}}.
|
||||
|
||||
@item %@{@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if the @option{-@var{S}} switch is given to GCC@.
|
||||
|
||||
@item %@{!@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if the @option{-@var{S}} switch is @emph{not} given to GCC@.
|
||||
|
||||
@item %@{@var{S}*:@var{X}@}
|
||||
Substitutes @code{@var{X}} if one or more switches whose names start with
|
||||
@code{-@var{S}} are specified to GCC@. Normally @code{@var{X}} is substituted only
|
||||
once, no matter how many such switches appeared. However, if @code{%*}
|
||||
appears somewhere in @code{@var{X}}, then @code{@var{X}} is substituted once
|
||||
for each matching switch, with the @code{%*} replaced by the part of
|
||||
that switch matching the @code{*}.
|
||||
|
||||
If @code{%*} appears as the last part of a spec sequence then a space
|
||||
is added after the end of the last substitution. If there is more
|
||||
text in the sequence, however, then a space is not generated. This
|
||||
allows the @code{%*} substitution to be used as part of a larger
|
||||
string. For example, a spec string like this:
|
||||
|
||||
@smallexample
|
||||
%@{mcu=*:--script=%*/memory.ld@}
|
||||
@end smallexample
|
||||
|
||||
@noindent
|
||||
when matching an option like @option{-mcu=newchip} produces:
|
||||
|
||||
@smallexample
|
||||
--script=newchip/memory.ld
|
||||
@end smallexample
|
||||
|
||||
@item %@{.@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if processing a file with suffix @code{@var{S}}.
|
||||
|
||||
@item %@{!.@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if @emph{not} processing a file with suffix @code{@var{S}}.
|
||||
|
||||
@item %@{,@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if processing a file for language @code{@var{S}}.
|
||||
|
||||
@item %@{!,@var{S}:@var{X}@}
|
||||
Substitutes @code{@var{X}}, if not processing a file for language @code{@var{S}}.
|
||||
|
||||
@item %@{@var{S}|@var{P}:@var{X}@}
|
||||
Substitutes @code{@var{X}} if either @code{-@var{S}} or @code{-@var{P}} is given to
|
||||
GCC@. This may be combined with @samp{!}, @samp{.}, @samp{,}, and
|
||||
@code{*} sequences as well, although they have a stronger binding than
|
||||
the @samp{|}. If @code{%*} appears in @code{@var{X}}, all of the
|
||||
alternatives must be starred, and only the first matching alternative
|
||||
is substituted.
|
||||
|
||||
For example, a spec string like this:
|
||||
|
||||
@smallexample
|
||||
%@{.c:-foo@} %@{!.c:-bar@} %@{.c|d:-baz@} %@{!.c|d:-boggle@}
|
||||
@end smallexample
|
||||
|
||||
@noindent
|
||||
outputs the following command-line options from the following input
|
||||
command-line options:
|
||||
|
||||
@smallexample
|
||||
fred.c -foo -baz
|
||||
jim.d -bar -boggle
|
||||
-d fred.c -foo -baz -boggle
|
||||
-d jim.d -bar -baz -boggle
|
||||
@end smallexample
|
||||
|
||||
@item %@{%:@var{function}(@var{args}):@var{X}@}
|
||||
|
||||
Call function named @var{function} with args @var{args}. If the
|
||||
function returns non-NULL, then @code{@var{X}} is substituted, if it returns
|
||||
NULL, it isn't substituted.
|
||||
|
||||
@item %@{@var{S}:@var{X}; @var{T}:@var{Y}; :@var{D}@}
|
||||
|
||||
If @code{@var{S}} is given to GCC, substitutes @code{@var{X}}; else if @code{@var{T}} is
|
||||
given to GCC, substitutes @code{@var{Y}}; else substitutes @code{@var{D}}. There can
|
||||
be as many clauses as you need. This may be combined with @code{.},
|
||||
@code{,}, @code{!}, @code{|}, and @code{*} as needed.
|
||||
|
||||
|
||||
@end table
|
||||
|
||||
The switch matching text @code{@var{S}} in a @samp{%@{@var{S}@}}, @samp{%@{@var{S}:@var{X}@}}
|
||||
or similar construct can use a backslash to ignore the special meaning
|
||||
of the character following it, thus allowing literal matching of a
|
||||
character that is otherwise specially treated. For example,
|
||||
@samp{%@{std=iso9899\:1999:@var{X}@}} substitutes @code{@var{X}} if the
|
||||
@option{-std=iso9899:1999} option is given.
|
||||
|
||||
The conditional text @code{@var{X}} in a @samp{%@{@var{S}:@var{X}@}} or similar
|
||||
construct may contain other nested @samp{%} constructs or spaces, or
|
||||
even newlines. They are processed as usual, as described above.
|
||||
Trailing white space in @code{@var{X}} is ignored. White space may also
|
||||
appear anywhere on the left side of the colon in these constructs,
|
||||
except between @code{.} or @code{*} and the corresponding word.
|
||||
|
||||
The @option{-O}, @option{-f}, @option{-m}, and @option{-W} switches are
|
||||
handled specifically in these constructs. If another value of
|
||||
@option{-O} or the negated form of a @option{-f}, @option{-m}, or
|
||||
@option{-W} switch is found later in the command line, the earlier
|
||||
switch value is ignored, except with @{@code{@var{S}}*@} where @code{@var{S}} is
|
||||
just one letter, which passes all matching options.
|
||||
|
||||
The character @samp{|} at the beginning of the predicate text is used to
|
||||
indicate that a command should be piped to the following command, but
|
||||
only if @option{-pipe} is specified.
|
||||
|
||||
It is built into GCC which switches take arguments and which do not.
|
||||
(You might think it would be useful to generalize this to allow each
|
||||
compiler's spec to say which switches take arguments. But this cannot
|
||||
be done in a consistent fashion. GCC cannot even decide which input
|
||||
files have been specified without knowing which switches take arguments,
|
||||
and it must know which input files to compile in order to tell which
|
||||
compilers to run).
|
||||
|
||||
GCC also knows implicitly that arguments starting in @option{-l} are to be
|
||||
treated as compiler output files, and passed to the linker in their
|
||||
proper position among the other output files.
|
||||
Reference in New Issue
Block a user