[ASan] Add metadata to renamed instructions so ASan doesn't use the incorrect name

Author: gbMattN

llvm/lib/IR/ValueSymbolTable.cpp

@@ -123,6 +123,14 @@ ValueName *ValueSymbolTable::createValueName(StringRef Name, Value *V) {
   }
 
   // Otherwise, there is a naming conflict.  Rename this value.
+  // If we are renaming an instruction, ASan needs to know for it to serialize
+  // properly
+  if (auto *I = dyn_cast<Instruction>(V)) {
+    MDString *trueNameMetadata = MDString::get(V->getContext(), Name);
+    llvm::MDTuple *tuple =
+        llvm::MDTuple::get(V->getContext(), trueNameMetadata);
+    I->setMetadata("OriginalName", tuple);
+  }
   SmallString<256> UniqueName(Name.begin(), Name.end());
   return makeUniqueName(V, UniqueName);
 }

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -3430,7 +3430,12 @@ void FunctionStackPoisoner::processStaticAllocas() {
   SmallVector<ASanStackVariableDescription, 16> SVD;
   SVD.reserve(AllocaVec.size());
   for (AllocaInst *AI : AllocaVec) {
-    ASanStackVariableDescription D = {AI->getName().data(),
+    std::string Name = AI->getName().data();
+    if (AI->hasMetadata("OriginalName")) {
+      MDTuple *tuple = dyn_cast<MDTuple>(AI->getMetadata("OriginalName"));
+      Name = dyn_cast<MDString>(tuple->getOperand(0))->getString();
+    }
+    ASanStackVariableDescription D = {Name.c_str(),
                                       ASan.getAllocaSizeInBytes(*AI),
                                       0,
                                       AI->getAlign().value(),