Fix MinGW build with _WIN32_WINNT<0x600, GCC>=13, model=win32 #132
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simark
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Dec 10, 2024
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unordered_dense.h fails to compile on Windows/MinGW with GCC >= 13
with thread model win32, and _WIN32_WINNT < 0x600 (Vista), in
CFLAGS/CXXFLAGS. E.g., GDB defines _WIN32_WINNT to 0x501, and it
fails to build with GCC 14.2 like so:
CXX ada-exp.o
In file included from /opt/xpack-mingw-w64-gcc-14.2.0-1/x86_64-w64-mingw32/include/c++/14.2.0/shared_mutex:42,
from /opt/xpack-mingw-w64-gcc-14.2.0-1/x86_64-w64-mingw32/include/c++/14.2.0/memory_resource:66,
from /home/pedro/gdb/src/gdb/../gdbsupport/unordered_dense.h:104,
from /home/pedro/gdb/src/gdb/../gdbsupport/unordered_map.h:21,
from /home/pedro/gdb/src/gdb/gdbtypes.h:53,
from /home/pedro/gdb/src/gdb/expression.h:23,
from /home/pedro/gdb/src/gdb/ada-exp.y:40:
/opt/xpack-mingw-w64-gcc-14.2.0-1/x86_64-w64-mingw32/include/c++/14.2.0/bits/std_mutex.h:164:5: error: '__gthread_cond_t' does not name a type; did you mean '__gthread_once_t'?
164 | __gthread_cond_t* native_handle() noexcept { return &_M_cond; }
| ^~~~~~~~~~~~~~~~
| __gthread_once_t
(... snip other instances of same ...)
The problem is that unordered_dense.h includes <memory_resource>,
which uses std::mutex, and thus needs to include <mutex>. (See
<https://quuxplusone.github.io/blog/2018/06/05/libcpp-memory-resource>,
"Notice that synchronized_pool_resource contains a mutex, which means
that <memory_resource> effectively must include <mutex>.")
GCC 13 rewrote the win32 thread model support, and in that rewrite,
support for __gthread_cond_t in std_mutex.h became conditional on
_WIN32_WINNT >= 0x600.
GCC/libstdc++ also has <experimental/memory_resource> so with this
patch, such a configuration takes that branch and succeeds, because
<experimental/memory_resource> does not include <mutex>.
Tested with MinGW-w64 GCC 14.2, posix and win32 models.
Tested with MinGW-w64 GCC 10.1, posix and win32 models.
Tested with GNU/Linux GCC 11.4.0.
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Owner
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Thanks, and sorry it took me so long |
kraj
pushed a commit
to kraj/binutils-gdb
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this pull request
Oct 8, 2025
This version brings a fix made by Pedro [1] to fix compilation on some Windows systems. [1] martinus/unordered_dense#132 Change-Id: I5cedec0e644074e2274346ecc1c73e5be00f84b0
saagarjha
pushed a commit
to ahjragaas/binutils-gdb
that referenced
this pull request
Oct 27, 2025
This version brings a fix made by Pedro [1] to fix compilation on some Windows systems. [1] martinus/unordered_dense#132 Change-Id: I5cedec0e644074e2274346ecc1c73e5be00f84b0 Approved-By: Tom Tromey <tom@tromey.com>
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unordered_dense.h fails to compile on Windows/MinGW with GCC >= 13 with thread model win32, and _WIN32_WINNT < 0x600 (Vista), in CFLAGS/CXXFLAGS. E.g., GDB defines _WIN32_WINNT to 0x501, and it fails to build with GCC 14.2 like so:
The problem is that unordered_dense.h includes
<memory_resource>, which usesstd::mutex, and thus needs to include<mutex>. (See https://quuxplusone.github.io/blog/2018/06/05/libcpp-memory-resource, "Notice that synchronized_pool_resource contains a mutex, which means that<memory_resource>effectively must include<mutex>.")GCC 13 rewrote the win32 thread model support, and in that rewrite, support for
__gthread_cond_tinstd_mutex.hbecame conditional on_WIN32_WINNT >= 0x600.GCC/libstdc++ also has
<experimental/memory_resource>so with this patch, such a configuration takes that branch and succeeds, because<experimental/memory_resource>does not include<mutex>.Tested with MinGW-w64 GCC 14.2, posix and win32 models.
Tested with MinGW-w64 GCC 10.1, posix and win32 models.
Tested with GNU/Linux GCC 11.4.0.