Set _WIN32_WINNT in common.m4 configure check
Commit Message
GCC recently added support for the Windows thread model, enabling
libstdc++ to support Windows natively. However, this supporrt
requires a version of Windows later than the minimum version that is
supported by GDB.
PR build/29966 points out that the GDB configure test for std::thread
does not work in this situation, because _WIN32_WINNT is not defined
in test program, and so <thread> seems to be fine.
This patch is an attempt to fix the problem, by using the same setting
for _WIN32_WINNT at configure time as is used at build time.
I don't have access to one of the older systems so I don't think I can
truly test this. I did do a mingw cross build, though. I'm going to
ask the bug reporter to test it.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29966
---
gdb/configure | 12 +++++++++++-
gdbserver/configure | 12 +++++++++++-
gdbsupport/common-defs.h | 4 +++-
gdbsupport/common.m4 | 13 ++++++++++++-
gdbsupport/configure | 12 +++++++++++-
5 files changed, 48 insertions(+), 5 deletions(-)
Comments
>>>>> "Tom" == Tom Tromey via Gdb-patches <gdb-patches@sourceware.org> writes:
Tom> I don't have access to one of the older systems so I don't think I can
Tom> truly test this. I did do a mingw cross build, though. I'm going to
Tom> ask the bug reporter to test it.
BTW, if this works, I think we should consider it for GDB 13.
Tom
> Cc: Tom Tromey <tromey@adacore.com>
> Date: Mon, 9 Jan 2023 07:47:16 -0700
> From: Tom Tromey via Gdb-patches <gdb-patches@sourceware.org>
>
> GCC recently added support for the Windows thread model, enabling
> libstdc++ to support Windows natively. However, this supporrt
> requires a version of Windows later than the minimum version that is
> supported by GDB.
>
> PR build/29966 points out that the GDB configure test for std::thread
> does not work in this situation, because _WIN32_WINNT is not defined
> in test program, and so <thread> seems to be fine.
>
> This patch is an attempt to fix the problem, by using the same setting
> for _WIN32_WINNT at configure time as is used at build time.
>
> I don't have access to one of the older systems so I don't think I can
> truly test this. I did do a mingw cross build, though. I'm going to
> ask the bug reporter to test it.
The patch LGTM, but of course actually testing on an old system would
be the best.
Thanks.
>>>>> "Tom" == Tom Tromey via Gdb-patches <gdb-patches@sourceware.org> writes:
Tom> GCC recently added support for the Windows thread model, enabling
Tom> libstdc++ to support Windows natively. However, this supporrt
Tom> requires a version of Windows later than the minimum version that is
Tom> supported by GDB.
Tom> PR build/29966 points out that the GDB configure test for std::thread
Tom> does not work in this situation, because _WIN32_WINNT is not defined
Tom> in test program, and so <thread> seems to be fine.
Tom> This patch is an attempt to fix the problem, by using the same setting
Tom> for _WIN32_WINNT at configure time as is used at build time.
Tom> I don't have access to one of the older systems so I don't think I can
Tom> truly test this. I did do a mingw cross build, though. I'm going to
Tom> ask the bug reporter to test it.
There turns out to also be some small problem in libstdc++ so this patch
can't fully be confirmed. However it also seems like an improvement, so
I am going to check it in.
Joel, I tend to think we should consider this for GDB 13. Without it,
GDB 13 won't build with a newer GCC on some older Windows systems.
Tom
Hi Tom,
> Tom> GCC recently added support for the Windows thread model, enabling
> Tom> libstdc++ to support Windows natively. However, this supporrt
> Tom> requires a version of Windows later than the minimum version that is
> Tom> supported by GDB.
>
> Tom> PR build/29966 points out that the GDB configure test for std::thread
> Tom> does not work in this situation, because _WIN32_WINNT is not defined
> Tom> in test program, and so <thread> seems to be fine.
>
> Tom> This patch is an attempt to fix the problem, by using the same setting
> Tom> for _WIN32_WINNT at configure time as is used at build time.
>
> Tom> I don't have access to one of the older systems so I don't think I can
> Tom> truly test this. I did do a mingw cross build, though. I'm going to
> Tom> ask the bug reporter to test it.
>
> There turns out to also be some small problem in libstdc++ so this patch
> can't fully be confirmed. However it also seems like an improvement, so
> I am going to check it in.
>
> Joel, I tend to think we should consider this for GDB 13. Without it,
> GDB 13 won't build with a newer GCC on some older Windows systems.
Thanks for the heads up, Tom. Sounds good to me!
@@ -24969,7 +24969,17 @@ if ${gdb_cv_cxx_std_thread+:} false; then :
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
-#include <thread>
+ #if defined (__MINGW32__) || defined (__CYGWIN__)
+ # ifdef _WIN32_WINNT
+ # if _WIN32_WINNT < 0x0501
+ # undef _WIN32_WINNT
+ # define _WIN32_WINNT 0x0501
+ # endif
+ # else
+ # define _WIN32_WINNT 0x0501
+ # endif
+ #endif /* __MINGW32__ || __CYGWIN__ */
+ #include <thread>
void callback() { }
int
main ()
@@ -7951,7 +7951,17 @@ if ${gdb_cv_cxx_std_thread+:} false; then :
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
-#include <thread>
+ #if defined (__MINGW32__) || defined (__CYGWIN__)
+ # ifdef _WIN32_WINNT
+ # if _WIN32_WINNT < 0x0501
+ # undef _WIN32_WINNT
+ # define _WIN32_WINNT 0x0501
+ # endif
+ # else
+ # define _WIN32_WINNT 0x0501
+ # endif
+ #endif /* __MINGW32__ || __CYGWIN__ */
+ #include <thread>
void callback() { }
int
main ()
@@ -70,7 +70,9 @@
/* We don't support Windows versions before XP, so we define
_WIN32_WINNT correspondingly to ensure the Windows API headers
- expose the required symbols. */
+ expose the required symbols.
+
+ NOTE: this must be kept in sync with common.m4. */
#if defined (__MINGW32__) || defined (__CYGWIN__)
# ifdef _WIN32_WINNT
# if _WIN32_WINNT < 0x0501
@@ -100,7 +100,18 @@ AC_DEFUN([GDB_AC_COMMON], [
AC_CACHE_CHECK([for std::thread],
gdb_cv_cxx_std_thread,
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
- [[#include <thread>
+ dnl NOTE: this must be kept in sync with common-defs.h.
+ [[#if defined (__MINGW32__) || defined (__CYGWIN__)
+ # ifdef _WIN32_WINNT
+ # if _WIN32_WINNT < 0x0501
+ # undef _WIN32_WINNT
+ # define _WIN32_WINNT 0x0501
+ # endif
+ # else
+ # define _WIN32_WINNT 0x0501
+ # endif
+ #endif /* __MINGW32__ || __CYGWIN__ */
+ #include <thread>
void callback() { }]],
[[std::thread t(callback);]])],
gdb_cv_cxx_std_thread=yes,
@@ -8967,7 +8967,17 @@ if ${gdb_cv_cxx_std_thread+:} false; then :
else
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
-#include <thread>
+ #if defined (__MINGW32__) || defined (__CYGWIN__)
+ # ifdef _WIN32_WINNT
+ # if _WIN32_WINNT < 0x0501
+ # undef _WIN32_WINNT
+ # define _WIN32_WINNT 0x0501
+ # endif
+ # else
+ # define _WIN32_WINNT 0x0501
+ # endif
+ #endif /* __MINGW32__ || __CYGWIN__ */
+ #include <thread>
void callback() { }
int
main ()