This commit aims to not make use of -Wmissing-prototypes when
compiling with g++.
Use of -Wmissing-prototypes was added with this commit:
commit a0761e34f0
Date: Wed Mar 11 15:15:12 2020 -0400
gdb: enable -Wmissing-prototypes warning
Because clang can provide helpful warnings with this flag.
Unfortunately, g++ doesn't accept this flag, and will give this
warning:
cc1plus: warning: command line option ‘-Wmissing-prototypes’ is valid for C/ObjC but not for C++
In theory the fact that this flag is not supported should be detected
by the configure check in gdbsupport/warning.m4, but for users of
ccache, this check doesn't work due to a long standing ccache issue:
https://github.com/ccache/ccache/issues/738
The ccache problem is that -W... options are reordered on the command
line, and so -Wmissing-prototypes is seen before -Werror. Usually
this doesn't matter, but the above warning (about the flag not being
valid) is issued before the -Werror flag is processed, and so is not
fatal.
There have been two previous attempts to fix this that I'm aware of.
The first is:
https://sourceware.org/pipermail/gdb-patches/2021-September/182148.html
In this attempt, instead of just relying on a compile to check if a
flag is valid, the proposal was to both compile and link. As linking
doesn't go through ccache, we don't suffer from the argument
reordering problem, and the link phase will correctly fail when using
-Wmissing-prototypes with g++. The configure script will then disable
the use of this flag.
This approach was rejected, and the suggestion was to only add the
-Wmissing-prototypes flag if we are compiling with gcc.
The second attempt, attempts this approach, and can be found here:
https://sourceware.org/pipermail/gdb-patches/2021-November/183076.html
This attempt only adds the -Wmissing-prototypes flag is the value of
GCC is not 'yes'. This feels like it is doing the right thing,
unfortunately, the GCC flag is really a 'is gcc like' flag, not a
strict, is gcc check. As such, GCC is set to 'yes' for clang, which
would mean the flag was not included for clang or gcc. The entire
point of the original commit was to add this flag for clang, so
clearly the second attempt is not sufficient either.
In this new attempt I have added gdbsupport/compiler-type.m4, this
file defines AM_GDB_COMPILER_TYPE. This macro sets the variable
GDB_COMPILER_TYPE to either 'gcc', 'clang', or 'unknown'. In future
the list of values might be extended to cover other compilers, if this
is ever useful.
I've then modified gdbsupport/warning.m4 to only add the problematic
-Wmissing-prototypes flag if GDB_COMPILER_TYPE is not 'gcc'.
I've tested this with both gcc and clang and see the expected results,
gcc no longer attempts to use the -Wmissing-prototypes flag, while
clang continues to use it.
When compiling using ccache, I am no longer seeing the warning.
ptrace.m4, providing the GDB_AC_PTRACE autoconf macro, is used by gdb,
gdbserver and gdbsupport. I think it would make sense to move it to
gdbsupport.
gdb/ChangeLog:
* acinclude.m4: Update ptrace.m4 path.
* ptrace.m4: Moved to gdbsupport.
gdbserver/ChangeLog:
* acinclude.m4: Update ptrace.m4 path.
gdbsupport/ChangeLog:
* Makefile.in: Re-generate.
* acinclude.m4: Update ptrace.m4 path.
* ptrace.m4: Move here.
Change-Id: I849c149fd5dd8c3b2b0af38654fb353e3727871b
The selftest.m4 file is used by gdb, gdbserver and gdbsupport, I think
it belongs in gdbsupport.
gdb/ChangeLog:
* selftest.m4: Move to gdbsupport/.
* acinclude.m4: Update path to selftest.m4.
gdbserver/ChangeLog:
* acinclude.m4: Update path to selftest.m4.
gdbsupport/ChangeLog:
* selftest.m4: Moved from gdb/.
* acinclude.m4: Update path to selftest.m4.
This file is used by gdbsupport, gdbserver and gdb, so I think it
belongs in gdbsupport. Move it there and update the references the
various acinclude.m4 files.
gdbsupport/ChangeLog:
* warning.m4: Move here, from gdb/warning.m4.
* acinclude.m4: Update warning.m4 path.
* Makefile.in: Re-generate.
gdbserver/ChangeLog:
* acinclude.m4: Update warning.m4 path.
gdb/ChangeLog:
* acinclude: Update warning.m4 path.
* warning.m4: Move to gdbsupport.
Since gdbsupport has been given its own build system, it is no longer
compiled with the warning flags specified in gdb/warning.m4.
This patch makes it use AM_GDB_WARNINGS.
gdbsupport/ChangeLog:
* acinclude.m4: Include ../gdb/warning.m4.
* configure.ac: Use AM_GDB_WARNINGS.
* Makefile.am: Set AM_CFLAGS to WARN_CFLAGS and WERROR_CFLAGS.
* Makefile.in: Re-generate.
* configure: Re-generate.
This moves many needed configure checks from gdb and gdbserver into
common.m4. This helps gdbsupport, nat, and target be self-contained.
The result is a bit spaghetti-ish, because gdbsupport uses another m4
file from gdb/. The resulting code is somewhat non-obvious. However,
these problems already exist, so it's not really that much worse than
what is already done.
gdb/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* configure: Rebuild.
* configure.ac: Move many checks to ../gdbsupport/common.m4.
gdb/gdbserver/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* configure: Rebuild.
* configure.ac: Remove any checks that were added to common.m4.
* acinclude.m4: Include lib-ld.m4, lib-prefix.m4, and
lib-link.m4.
gdbsupport/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* configure, Makefile.in, aclocal.m4, common.m4, config.in:
Rebuild.
* common.m4 (GDB_AC_COMMON): Move many checks from
gdb/configure.ac.
* acinclude.m4: Include bfd.m4, ptrace.m4.
Change-Id: I931eaa94065df268b30a2f1354390710df89c7f8
This patch moves the gdbsupport directory to the top level. This is
the next step in the ongoing project to move gdbserver to the top
level.
The bulk of this patch was created by "git mv gdb/gdbsupport gdbsupport".
This patch then adds a build system to gdbsupport and wires it into
the top level. Then it changes gdb to use the top-level build.
gdbserver, on the other hand, is not yet changed. It still does its
own build of gdbsupport.
ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* src-release.sh (GDB_SUPPORT_DIRS): Add gdbsupport.
* MAINTAINERS: Add gdbsupport.
* configure: Rebuild.
* configure.ac (configdirs): Add gdbsupport.
* gdbsupport: New directory, move from gdb/gdbsupport.
* Makefile.def (host_modules, dependencies): Add gnulib.
* Makefile.in: Rebuild.
gdb/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* nat/x86-linux-dregs.c: Include configh.h.
* nat/linux-ptrace.c: Include configh.h.
* nat/linux-btrace.c: Include configh.h.
* defs.h: Include config.h, bfd.h.
* configure.ac: Don't source common.host.
(CONFIG_OBS, CONFIG_SRCS): Remove gdbsupport files.
* configure: Rebuild.
* acinclude.m4: Update path.
* Makefile.in (SUPPORT, LIBSUPPORT, INCSUPPORT): New variables.
(CONFIG_SRC_SUBDIR): Remove gdbsupport.
(INTERNAL_CFLAGS_BASE): Add INCSUPPORT.
(CLIBS): Add LIBSUPPORT.
(CDEPS): Likewise.
(COMMON_SFILES): Remove gdbsupport files.
(HFILES_NO_SRCDIR): Likewise.
(stamp-version): Update path to create-version.sh.
(ALLDEPFILES): Remove gdbsupport files.
gdb/gdbserver/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* server.h: Include config.h.
* gdbreplay.c: Include config.h.
* configure: Rebuild.
* configure.ac: Don't source common.host.
* acinclude.m4: Update path.
* Makefile.in (INCSUPPORT): New variable.
(INCLUDE_CFLAGS): Add INCSUPPORT.
(SFILES): Update paths.
(version-generated.c): Update path to create-version.sh.
(gdbsupport/%-ipa.o, gdbsupport/%.o): Update paths.
gdbsupport/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* common-defs.h: Add GDBSERVER case. Update includes.
* acinclude.m4, aclocal.m4, config.in, configure, configure.ac,
Makefile.am, Makefile.in, README: New files.
* Moved from ../gdb/gdbsupport/
Change-Id: I07632e7798635c1bab389bf885971e584fb4bb78
