[compiler-rt] [compiler-rt] [fuzzer] Skip trying to set the thread name on MinGW (PR #115167)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Martin Storsjö (mstorsjo)

<details>
<summary>Changes</summary>

Since b4130bee6bfd34d8045f02fc9f951bcb5db9d85c, we check for _LIBCPP_HAS_THREAD_API_PTHREAD to decide between using SetThreadDescription or pthread_setname_np for setting the thread name.

c6f3b7bcd0596d30f8dabecdfb9e44f9a07b6e4c changed how libcxx defines their configuration macros - now they are always defined, but defined to 0 or 1, while they previously were either defined or undefined.

As these libcxx defines used to be defined to an empty string (rather than expanding to 1) if enabled, we can't easily produce an expression that works both with older and newer libcxx. Additionally, these defines are libcxx internal config macros that aren't a detail that isn't supported and isn't meant to be relied upon.

Simply skip trying to set thread name on MinGW as we can't easily know which kind of thread native handle we have. Setting the thread name is only a nice to have, quality of life improvement - things should work the same even without it.

Additionally, libfuzzer isn't generally usable on MinGW targets yet (Clang doesn't include it in the getSupportedSanitizers() method for the MinGW target), so this shouldn't make any difference in practice anyway.

---
Full diff: https://github.com/llvm/llvm-project/pull/115167.diff


1 Files Affected:

- (modified) compiler-rt/lib/fuzzer/FuzzerUtilWindows.cpp (+5-4) 


``````````diff
diff --git a/compiler-rt/lib/fuzzer/FuzzerUtilWindows.cpp b/compiler-rt/lib/fuzzer/FuzzerUtilWindows.cpp
index 37aecae7237ae9..2db2ea98d5c4f9 100644
--- a/compiler-rt/lib/fuzzer/FuzzerUtilWindows.cpp
+++ b/compiler-rt/lib/fuzzer/FuzzerUtilWindows.cpp
@@ -239,10 +239,11 @@ size_t PageSize() {
 }
 
 void SetThreadName(std::thread &thread, const std::string &name) {
-#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD) ||                                 \
-    defined(_GLIBCXX_GCC_GTHR_POSIX_H)
-  (void)pthread_setname_np(thread.native_handle(), name.c_str());
-#else
+#ifndef __MINGW32__
+  // Not setting the thread name in MinGW environments. MinGW C++ standard
+  // libraries can either use native Windows threads or pthreads, so we
+  // don't know with certainty what kind of thread handle we're getting
+  // from thread.native_handle() here.
   typedef HRESULT(WINAPI * proc)(HANDLE, PCWSTR);
   HMODULE kbase = GetModuleHandleA("KernelBase.dll");
   proc ThreadNameProc = reinterpret_cast<proc>(

``````````

</details>


https://github.com/llvm/llvm-project/pull/115167