[clang] [compiler-rt] [compiler-rt] Support `-shared-libsan` for Offload UBSan (PR #226551)

[Joseph Huber via llvm-commits]

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@@ -67,8 +67,15 @@ void Initialize() {
   if (UNLIKELY(!Offload::Get().Ready()))                                       \
     return REAL(name)(__VA_ARGS__);
 
-// PPC cannot transparently tail-call an indirect dlsym target for RTLD_NEXT.
-#if !SANITIZER_PPC
+// The dlsym interceptor is only transparent if it can tail-call, which PPC and
+// compilers without musttail cannot guarantee.
+#if defined(__has_cpp_attribute)
+#if __has_cpp_attribute(clang::musttail) && !SANITIZER_PPC
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jhuber6 wrote:

Yeah, the `dlsym` interception is the scummiest part of this, but it's necessary since there are users of HSA  through this method. I'll see what I can do.

https://github.com/llvm/llvm-project/pull/226551