[compiler-rt] [compiler-rt] Add MinGW GCC support for Windows sanitizer runtimes (PR #209902)

[via llvm-commits]

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@@ -332,15 +335,27 @@ ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
 #endif
 
 void InitializePlatformExceptionHandlers() {
-#if SANITIZER_WINDOWS64
+#  if SANITIZER_WINDOWS64
   // On Win64, we map memory on demand with access violation handler.
   // Install our exception handler.
   CHECK(AddVectoredExceptionHandler(TRUE, &ShadowExceptionHandler));
 #endif
 }
 
 bool IsSystemHeapAddress(uptr addr) {
-  return ::HeapValidate(GetProcessHeap(), 0, (void *)addr) != FALSE;
+  HANDLE process_heap = GetProcessHeap();
+  if (::HeapValidate(process_heap, 0, (void*)addr))
+    return true;
+
+#  if defined(__GNUC__) && !defined(__clang__)
+  HANDLE crt_heap = (HANDLE)_get_heap_handle();
+  if (crt_heap == process_heap)
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oltolm wrote:

This is only needed for MSVCRT because its private heap is distinct from the process heap. Support for MSVCRT has been deprecated in MSYS2, so I will drop this change from the PR.

https://github.com/llvm/llvm-project/pull/209902