gcc/doc/makefile.texi

@c Copyright (C) 2001-2020 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.

@node Makefile
@subsection Makefile Targets
@cindex makefile targets
@cindex targets, makefile

These targets are available from the @samp{gcc} directory:

@table @code
@item all
This is the default target.  Depending on what your build/host/target
configuration is, it coordinates all the things that need to be built.

@item doc
Produce info-formatted documentation and man pages.  Essentially it
calls @samp{make man} and @samp{make info}.

@item dvi
Produce DVI-formatted documentation.

@item pdf
Produce PDF-formatted documentation.

@item html
Produce HTML-formatted documentation.

@item man
Generate man pages.

@item info
Generate info-formatted pages.

@item mostlyclean
Delete the files made while building the compiler.

@item clean
That, and all the other files built by @samp{make all}.

@item distclean
That, and all the files created by @command{configure}.

@item maintainer-clean
Distclean plus any file that can be generated from other files.  Note
that additional tools may be required beyond what is normally needed to
build GCC.

@item srcextra
Generates files in the source directory that are not version-controlled but
should go into a release tarball.

@item srcinfo
@itemx srcman
Copies the info-formatted and manpage documentation into the source
directory usually for the purpose of generating a release tarball.

@item install
Installs GCC.

@item uninstall
Deletes installed files, though this is not supported.

@item check
Run the testsuite.  This creates a @file{testsuite} subdirectory that
has various @file{.sum} and @file{.log} files containing the results of
the testing.  You can run subsets with, for example, @samp{make check-gcc}.
You can specify specific tests by setting @env{RUNTESTFLAGS} to be the name
of the @file{.exp} file, optionally followed by (for some tests) an equals
and a file wildcard, like:

@smallexample
make check-gcc RUNTESTFLAGS="execute.exp=19980413-*"
@end smallexample

Note that running the testsuite may require additional tools be
installed, such as Tcl or DejaGnu.
@end table

The toplevel tree from which you start GCC compilation is not
the GCC directory, but rather a complex Makefile that coordinates
the various steps of the build, including bootstrapping the compiler
and using the new compiler to build target libraries.

When GCC is configured for a native configuration, the default action
for @command{make} is to do a full three-stage bootstrap.  This means
that GCC is built three times---once with the native compiler, once with
the native-built compiler it just built, and once with the compiler it
built the second time.  In theory, the last two should produce the same
results, which @samp{make compare} can check.  Each stage is configured
separately and compiled into a separate directory, to minimize problems
due to ABI incompatibilities between the native compiler and GCC.

If you do a change, rebuilding will also start from the first stage
and ``bubble'' up the change through the three stages.  Each stage
is taken from its build directory (if it had been built previously),
rebuilt, and copied to its subdirectory.  This will allow you to, for
example, continue a bootstrap after fixing a bug which causes the
stage2 build to crash.  It does not provide as good coverage of the
compiler as bootstrapping from scratch, but it ensures that the new
code is syntactically correct (e.g., that you did not use GCC extensions
by mistake), and avoids spurious bootstrap comparison
failures@footnote{Except if the compiler was buggy and miscompiled
some of the files that were not modified.  In this case, it's best
to use @command{make restrap}.}.

Other targets available from the top level include:

@table @code
@item bootstrap-lean
Like @code{bootstrap}, except that the various stages are removed once
they're no longer needed.  This saves disk space.

@item bootstrap2
@itemx bootstrap2-lean
Performs only the first two stages of bootstrap.  Unlike a three-stage
bootstrap, this does not perform a comparison to test that the compiler
is running properly.  Note that the disk space required by a ``lean''
bootstrap is approximately independent of the number of stages.

@item stage@var{N}-bubble (@var{N} = 1@dots{}4, profile, feedback)
Rebuild all the stages up to @var{N}, with the appropriate flags,
``bubbling'' the changes as described above.

@item all-stage@var{N} (@var{N} = 1@dots{}4, profile, feedback)
Assuming that stage @var{N} has already been built, rebuild it with the
appropriate flags.  This is rarely needed.

@item cleanstrap
Remove everything (@samp{make clean}) and rebuilds (@samp{make bootstrap}).

@item compare
Compares the results of stages 2 and 3.  This ensures that the compiler
is running properly, since it should produce the same object files
regardless of how it itself was compiled.

@item profiledbootstrap
Builds a compiler with profiling feedback information.  In this case,
the second and third stages are named @samp{profile} and @samp{feedback},
respectively.  For more information, see the installation instructions.

@item restrap
Restart a bootstrap, so that everything that was not built with
the system compiler is rebuilt.

@item stage@var{N}-start (@var{N} = 1@dots{}4, profile, feedback)
For each package that is bootstrapped, rename directories so that,
for example, @file{gcc} points to the stage@var{N} GCC, compiled
with the stage@var{N-1} GCC@footnote{Customarily, the system compiler
is also termed the @file{stage0} GCC.}.

You will invoke this target if you need to test or debug the
stage@var{N} GCC@.  If you only need to execute GCC (but you need
not run @samp{make} either to rebuild it or to run test suites),
you should be able to work directly in the @file{stage@var{N}-gcc}
directory.  This makes it easier to debug multiple stages in
parallel.

@item stage
For each package that is bootstrapped, relocate its build directory
to indicate its stage.  For example, if the @file{gcc} directory
points to the stage2 GCC, after invoking this target it will be
renamed to @file{stage2-gcc}.

@end table

If you wish to use non-default GCC flags when compiling the stage2 and
stage3 compilers, set @code{BOOT_CFLAGS} on the command line when doing
@samp{make}.

Usually, the first stage only builds the languages that the compiler
is written in: typically, C and maybe Ada.  If you are debugging a
miscompilation of a different stage2 front-end (for example, of the
Fortran front-end), you may want to have front-ends for other languages
in the first stage as well.  To do so, set @code{STAGE1_LANGUAGES}
on the command line when doing @samp{make}.

For example, in the aforementioned scenario of debugging a Fortran
front-end miscompilation caused by the stage1 compiler, you may need a
command like

@example
make stage2-bubble STAGE1_LANGUAGES=c,fortran
@end example

Alternatively, you can use per-language targets to build and test
languages that are not enabled by default in stage1.  For example,
@command{make f951} will build a Fortran compiler even in the stage1
build directory.