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From: Jonas Karlsson <jonas.karlsson@qt.io>
Subject: [PATCH] PhysX: Do not take Windows for the Microsoft compiler
Two of the things PhysX reaches for on Windows are extensions that only
the Microsoft compilers have, and it asks for them behind a test for the
platform rather than for the compiler, so the MinGW builds get them too.
- PxThreadImpl::setName() tells the debugger the thread name by raising a
Microsoft specific exception and catching it with __try/__except, which
MinGW does not implement, so the build fails to compile. MSVC and
clang-cl do support it, and the thread names are useful in a debugger,
so keep it for them.
- PX_ALIGN and friends spell the alignment __declspec(align()), which
clang and gcc silently do nothing with, and define PX_ALIGN_SUFFIX,
which is the form that would work there, empty. The alignment is lost:
PxSListEntry SharedQueueEntry
llvm-mingw, before 8 (align 8) 24 (align 8)
llvm-mingw, after 16 (align 16) 32 (align 16)
Linux, MSVC 16 (align 16) 32 (align 16)
PxSListEntry is what PxSList puts in the Windows interlocked singly
linked lists, and those pack the pointer on x86-64 in a way that needs
those 16 bytes: with the entries of a pool 8 bytes apart,
InterlockedPopEntrySList hands back an address that was never pushed.
The default CPU dispatcher keeps its task queue in one of these, so a
worker thread writes the object reference of a task through a pointer
like 0xffffffffffffff00, and the process dies with an access violation
in the task queue, or carries on with a task that is not a task.
Reproduced against this copy with llvm-mingw 20260908 and wine: 40 scenes
of 24 bodies with 4 worker threads crashed on two runs in three before
the alignment half, and on none after it. That non-determinism is the
shape of the failures in the Windows MinGW configurations, where a
different set of the tests dies each run.
The thread naming half is the corresponding half of the PhysX 4.1 patch
"fix PhysX windows build", forward ported to 5.9.0 and narrowed: the 4.1
version compiled the block out with #if 0 for every compiler. The other
half of that patch commented out four struct size assertions, three of
which are gone with the articulation implementation they belonged to, and
the remaining one holds in all the builds available here.
---
src/3rdparty/PhysX/include/foundation/PxPreprocessor.h | 5 ++++-
src/3rdparty/PhysX/source/foundation/windows/FdWindowsThread.cpp | 6 ++++++
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/src/3rdparty/PhysX/include/foundation/PxPreprocessor.h b/src/3rdparty/PhysX/include/foundation/PxPreprocessor.h
--- a/src/3rdparty/PhysX/include/foundation/PxPreprocessor.h
+++ b/src/3rdparty/PhysX/include/foundation/PxPreprocessor.h
@@ -382,7 +382,10 @@ struct A {
This declaration style is parsed correctly by Visual Assist.
*/
#ifndef PX_ALIGN
- #if PX_WINDOWS_FAMILY
+ // the question is which compiler this is, not which platform: __declspec(align()) is
+ // the Microsoft compilers' spelling, and the ones on Windows that are not Microsoft
+ // silently do nothing with it
+ #if PX_VC
#define PX_ALIGN(alignment, decl) __declspec(align(alignment)) decl
#define PX_ALIGN_PREFIX(alignment) __declspec(align(alignment))
#define PX_ALIGN_SUFFIX(alignment)
diff --git a/src/3rdparty/PhysX/source/foundation/windows/FdWindowsThread.cpp b/src/3rdparty/PhysX/source/foundation/windows/FdWindowsThread.cpp
--- a/src/3rdparty/PhysX/source/foundation/windows/FdWindowsThread.cpp
+++ b/src/3rdparty/PhysX/source/foundation/windows/FdWindowsThread.cpp
@@ -325,6 +325,9 @@ void PxThreadImpl::setName(const char* name)
// C++ Exceptions are disabled for this project, but SEH is not (and cannot be)
+ // PT: __try/__except is structured exception handling, which only the Microsoft
+ // compilers, including clang-cl, implement. MinGW just cannot name the thread.
+#if PX_VC
__try
{
RaiseException(NS_MS_VC_EXCEPTION, 0, sizeof(info) / sizeof(ULONG_PTR), (ULONG_PTR*)&info);
@@ -333,6 +336,9 @@ void PxThreadImpl::setName(const char* name)
{
// this runs if not attached to a debugger (thus not really naming the thread)
}
+#else
+ PX_UNUSED(info);
+#endif
}
}