[compiler-rt] [llvm] [msan] Add experimental '-mllvm -msan-embed-faulting-instruction' and MSAN_OPTIONS=print_faulting_instruction (PR #136539)

[Thurston Dang via llvm-commits]

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@@ -386,44 +420,88 @@ MSAN_MAYBE_STORE_ORIGIN(u16, 2)
 MSAN_MAYBE_STORE_ORIGIN(u32, 4)
 MSAN_MAYBE_STORE_ORIGIN(u64, 8)
 
-void __msan_warning() {
-  GET_CALLER_PC_BP;
-  PrintWarningWithOrigin(pc, bp, 0);
-  if (__msan::flags()->halt_on_error) {
-    if (__msan::flags()->print_stats)
-      ReportStats();
-    Printf("Exiting\n");
-    Die();
+// These macros to reuse the function body are kludgy, but are better than the
+// alternatives:
+// - call a common function: this pollutes the stack traces
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thurstond wrote:

Polluting is bad, yo (we don't want extra wrappers in the stack trace)

https://github.com/llvm/llvm-project/pull/136539