[llvm-branch-commits] [compiler-rt] release/19.x: [compiler-rt] [fuzzer] Skip trying to set the thread name on MinGW (#115167) (PR #115287)

[Tobias Hieta via llvm-branch-commits]

https://github.com/tru updated https://github.com/llvm/llvm-project/pull/115287

>From d174e2a5538984bca3d31ac41aff71528bb28747 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin at martin.st>
Date: Thu, 7 Nov 2024 00:18:57 +0200
Subject: [PATCH] [compiler-rt] [fuzzer] Skip trying to set the thread name on
 MinGW (#115167)

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.

(cherry picked from commit 87f4bc0acad65b1d20160d4160c7778b187125fc)
---
 compiler-rt/lib/fuzzer/FuzzerUtilWindows.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/compiler-rt/lib/fuzzer/FuzzerUtilWindows.cpp b/compiler-rt/lib/fuzzer/FuzzerUtilWindows.cpp
index 73eea07cf869ff..da3eb3cfb34063 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 =