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Makefile.in: Add optinfo.texi.
2013-12-20 Sharad Singhai <singhai@google.com> * Makefile.in: Add optinfo.texi. * doc/invoke.texi: Fix typo. * doc/optinfo.texi: New documentation for optimization info. * doc/passes.texi: Add new node. From-SVN: r206161
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Sharad Singhai
Sharad Singhai
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@ -1,3 +1,10 @@
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2013-12-20 Sharad Singhai <singhai@google.com>
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* Makefile.in: Add optinfo.texi.
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* doc/invoke.texi: Fix typo.
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* doc/optinfo.texi: New documentation for optimization info.
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* doc/passes.texi: Add new node.
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2013-12-20 Trevor saunders <tsaunders@mozilla.com>
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* vec.h (stack_vec): Convert to a templaate specialization of
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@ -2808,7 +2808,7 @@ TEXI_GCCINT_FILES = gccint.texi gcc-common.texi gcc-vers.texi \
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configfiles.texi collect2.texi headerdirs.texi funding.texi \
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gnu.texi gpl_v3.texi fdl.texi contrib.texi languages.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
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loop.texi generic.texi gimple.texi plugins.texi optinfo.texi
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TEXI_GCCINSTALL_FILES = install.texi install-old.texi fdl.texi \
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gcc-common.texi gcc-vers.texi
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@ -6507,7 +6507,7 @@ gcc -fopt-info-vec-missed=vec.miss -fopt-info-loop-optimized=loop.opt
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Here the two output filenames @file{vec.miss} and @file{loop.opt} are
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in conflict since only one output file is allowed. In this case, only
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the first option takes effect and the subsequent options are
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ignored. Thus only the @file{vec.miss} is produced which cotaints
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ignored. Thus only the @file{vec.miss} is produced which contains
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dumps from the vectorizer about missed opportunities.
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@item -frandom-seed=@var{string}
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228
gcc/doc/optinfo.texi
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228
gcc/doc/optinfo.texi
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@ -0,0 +1,228 @@
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@c Copyright (C) 2013 Free Software Foundation, Inc.
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@c This is part of the GCC manual.
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@c For copying conditions, see the file gcc.texi.
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@cindex optimization dumps
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This section is describes dump infrastructure which is common to both
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pass dumps as well as optimization dumps. The goal for this
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infrastructure is to provide both gcc developers and users detailed
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information about various compiler transformations and optimizations.
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@menu
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* Dump setup:: Setup of optimization dumps.
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* Optimization groups:: Groups made up of optimization passes.
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* Dump output verbosity:: How much information to dump.
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* Dump files and streams:: Dump output file names and streams.
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* Dump types:: Various types of dump functions.
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* Dump examples:: Sample usage.
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@end menu
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@node Dump setup
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@subsection Dump setup
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@cindex dump setup
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A dump_manager class is defined in @file{dumpfile.h}. Various passes
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register dumping pass-specific information via @code{dump_register} in
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@file{passes.c}. During the registration, an optimization pass can
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select its optimization group (@pxref{Optimization groups}). After
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that optimization information corresponding to the entire group
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(presumably from multiple passes) can be output via command-line
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switches. Note that if a pass does not fit into any of the pre-defined
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groups, it can select @code{OPTGROUP_NONE}.
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Note that in general, a pass need not know its dump output file name,
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whether certain flags are enabled, etc. However, for legacy reasons,
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passes could also call @code{dump_begin} which returns a stream in
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case the particular pass has optimization dumps enabled. A pass could
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call @code{dump_end} when the dump has ended. These methods should go
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away once all the passes are converted to use the new dump
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infrastructure.
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The recommended way to setup the dump output is via @code{dump_start}
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and @code{dump_end}.
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@node Optimization groups
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@subsection Optimization groups
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@cindex optimization groups
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The optimization passes are grouped into several categories. Currently
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defined categories in @file{dumpfile.h} are
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@ftable @code
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@item OPTGROUP_IPA
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IPA optimization passes. Enabled by @option{-ipa}
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@item OPTGROUP_LOOP
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Loop optimization passes. Enabled by @option{-loop}.
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@item OPTGROUP_INLINE
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Inlining passes. Enabled by @option{-inline}.
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@item OPTGROUP_VEC
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Vectorization passes. Enabled by @option{-vec}.
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@item OPTGROUP_OTHER
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All other optimization passes which do not fall into one of the above.
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@item OPTGROUP_ALL
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All optimization passes. Enabled by @option{-all}.
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@end ftable
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By using groups a user could selectively enable optimization
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information only for a group of passes. By default, the optimization
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information for all the passes is dumped.
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@node Dump files and streams
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@subsection Dump files and streams
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@cindex optimization info file names
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There are two separate output streams available for outputting
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optimization information from passes. Note that both these streams
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accept @code{stderr} and @code{stdout} as valid streams and thus it is
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possible to dump output to standard output or error. This is specially
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handy for outputting all available information in a single file by
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redirecting @code{stderr}.
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@table @code
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@item @code{pstream}
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This stream is for pass-specific dump output. For example,
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@option{-fdump-tree-vect=foo.v} dumps tree vectorization pass output
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into the given file name @file{foo.v}. If the file name is not provided,
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the default file name is based on the source file and pass number. Note
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that one could also use special file names @code{stdout} and
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@code{stderr} for dumping to standard output and standard error
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respectively.
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@item @code{alt_stream}
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This steam is used for printing optimization specific output in
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response to the @option{-fopt-info}. Again a file name can be given. If
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the file name is not given, it defaults to @code{stderr}.
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@end table
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@node Dump output verbosity
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@subsection Dump output verbosity
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@cindex dump verbosity
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The dump verbosity has the following options
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@table @samp
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@item optimized
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Print information when an optimization is successfully applied. It is
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up to a pass to decide which information is relevant. For example, the
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vectorizer passes print the source location of loops which got
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successfully vectorized.
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@item missed
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Print information about missed optimizations. Individual passes
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control which information to include in the output. For example,
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@smallexample
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gcc -O2 -ftree-vectorize -fopt-info-vec-missed
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@end smallexample
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will print information about missed optimization opportunities from
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vectorization passes on stderr.
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@item note
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Print verbose information about optimizations, such as certain
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transformations, more detailed messages about decisions etc.
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@item all
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Print detailed optimization information. This includes
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@var{optimized}, @var{missed}, and @var{note}.
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@end table
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@node Dump types
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@subsection Dump types
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@cindex dump types
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@ftable @code
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@item dump_printf
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This is a generic method for doing formatted output. It takes an
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additional argument @code{dump_kind} which signifies the type of
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dump. This method outputs information only when the dumps are enabled
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for this particular @code{dump_kind}. Note that the caller doesn't
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need to know if the particular dump is enabled or not, or even the
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file name. The caller only needs to decide which dump output
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information is relevant, and under what conditions. This determines
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the associated flags.
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Consider the following example from @file{loop-unroll.c} where an
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informative message about a loop (along with its location) is printed
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when any of the following flags is enabled
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@itemize @minus
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@item optimization messages
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@item RTL dumps
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@item detailed dumps
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@end itemize
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@example
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int report_flags = MSG_OPTIMIZED_LOCATIONS | TDF_RTL | TDF_DETAILS;
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dump_printf_loc (report_flags, locus,
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"loop turned into non-loop; it never loops.\n");
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@end example
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@item dump_basic_block
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Output basic block.
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@item dump_generic_expr
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Output generic expression.
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@item dump_gimple_stmt
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Output gimple statement.
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Note that the above methods also have variants prefixed with
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@code{_loc}, such as @code{dump_printf_loc}, which are similar except
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they also output the source location information.
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@end ftable
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@node Dump examples
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@subsection Dump examples
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@cindex dump examples
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@smallexample
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gcc -O3 -fopt-info-missed=missed.all
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@end smallexample
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outputs missed optimization report from all the passes into
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@file{missed.all}.
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As another example,
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@smallexample
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gcc -O3 -fopt-info-inline-optimized-missed=inline.txt
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@end smallexample
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will output information about missed optimizations as well as
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optimized locations from all the inlining passes into
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@file{inline.txt}.
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If the @var{filename} is provided, then the dumps from all the
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applicable optimizations are concatenated into the @file{filename}.
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Otherwise the dump is output onto @file{stderr}. If @var{options} is
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omitted, it defaults to @option{all-all}, which means dump all
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available optimization info from all the passes. In the following
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example, all optimization info is output on to @file{stderr}.
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@smallexample
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gcc -O3 -fopt-info
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@end smallexample
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Note that @option{-fopt-info-vec-missed} behaves the same as
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@option{-fopt-info-missed-vec}.
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As another example, consider
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@smallexample
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gcc -fopt-info-vec-missed=vec.miss -fopt-info-loop-optimized=loop.opt
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@end smallexample
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Here the two output file names @file{vec.miss} and @file{loop.opt} are
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in conflict since only one output file is allowed. In this case, only
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the first option takes effect and the subsequent options are
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ignored. Thus only the @file{vec.miss} is produced which containts
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dumps from the vectorizer about missed opportunities.
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@ -9,6 +9,7 @@
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@cindex passes and files of the compiler
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@cindex files and passes of the compiler
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@cindex compiler passes and files
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@cindex pass dumps
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This chapter is dedicated to giving an overview of the optimization and
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code generation passes of the compiler. In the process, it describes
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@ -22,6 +23,7 @@ where near complete.
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* Pass manager:: Sequencing the optimization passes.
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* Tree SSA passes:: Optimizations on a high-level representation.
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* RTL passes:: Optimizations on a low-level representation.
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* Optimization info:: Dumping optimization information from passes.
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@end menu
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@node Parsing pass
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@ -975,3 +977,7 @@ symbol table format, and @file{vmsdbgout.c} for VMS debug symbol table
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format.
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@end itemize
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@node Optimization info
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@section Optimization info
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@include optinfo.texi
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