[clang] [compiler-rt] [llvm] [ASan] Add metadata to renamed instructions so ASan doesn't use the i… (PR #119387)

[via llvm-commits]

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@@ -3430,13 +3430,15 @@ void FunctionStackPoisoner::processStaticAllocas() {
   SmallVector<ASanStackVariableDescription, 16> SVD;
   SVD.reserve(AllocaVec.size());
   for (AllocaInst *AI : AllocaVec) {
-    ASanStackVariableDescription D = {AI->getName().data(),
-                                      ASan.getAllocaSizeInBytes(*AI),
-                                      0,
-                                      AI->getAlign().value(),
-                                      AI,
-                                      0,
-                                      0};
+    const char *Name = AI->getName().data();
+    if (AI->hasMetadata(LLVMContext::MD_unaltered_name)) {
+      MDTuple *tuple =
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gbMattN wrote:

We only add this metadata in one place, and expect it to have a MDString in it. If dyn_cast fails and we try doing this to a `nullptr`, LLVM will exit with a stack trace and request for a bug report, which I think is what we'd want to happen

https://github.com/llvm/llvm-project/pull/119387