Now only emit metadata when using a ASan, and tag it with an enum rather than a string

Author: gbMattN

clang/lib/CodeGen/CGExpr.cpp

@@ -137,6 +137,14 @@ llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
     Alloca =
         new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(),
                              ArraySize, Name, AllocaInsertPt->getIterator());
+  if (Alloca->getName() != Name.str() &&
+      SanOpts.Mask & SanitizerKind::Address) {
+
+    llvm::LLVMContext &ctx = Alloca->getContext();
+    llvm::MDString *trueNameMetadata = llvm::MDString::get(ctx, Name.str());
+    llvm::MDTuple *tuple = llvm::MDTuple::get(ctx, trueNameMetadata);
+    Alloca->setMetadata(llvm::LLVMContext::MD_unaltered_name, tuple);
+  }
   if (Allocas) {
     Allocas->Add(Alloca);
   }

llvm/include/llvm/IR/FixedMetadataKinds.def

@@ -53,3 +53,4 @@ LLVM_FIXED_MD_KIND(MD_DIAssignID, "DIAssignID", 38)
 LLVM_FIXED_MD_KIND(MD_coro_outside_frame, "coro.outside.frame", 39)
 LLVM_FIXED_MD_KIND(MD_mmra, "mmra", 40)
 LLVM_FIXED_MD_KIND(MD_noalias_addrspace, "noalias.addrspace", 41)
+LLVM_FIXED_MD_KIND(MD_unaltered_name, "unaltered.name", 42)

llvm/lib/IR/ValueSymbolTable.cpp

@@ -123,14 +123,6 @@ 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

@@ -3430,18 +3430,15 @@ void FunctionStackPoisoner::processStaticAllocas() {
   SmallVector<ASanStackVariableDescription, 16> SVD;
   SVD.reserve(AllocaVec.size());
   for (AllocaInst *AI : AllocaVec) {
-    const char* Name = AI->getName().data();
-    if (AI->hasMetadata("OriginalName")) {
-      MDTuple *tuple = dyn_cast<MDTuple>(AI->getMetadata("OriginalName"));
+    const char *Name = AI->getName().data();
+    if (AI->hasMetadata(LLVMContext::MD_unaltered_name)) {
+      MDTuple *tuple =
+          dyn_cast<MDTuple>(AI->getMetadata(LLVMContext::MD_unaltered_name));
       Name = dyn_cast<MDString>(tuple->getOperand(0))->getString().data();
     }
-    ASanStackVariableDescription D = {Name,
-                                      ASan.getAllocaSizeInBytes(*AI),
-                                      0,
-                                      AI->getAlign().value(),
-                                      AI,
-                                      0,
-                                      0};
+    ASanStackVariableDescription D = {
+        Name, ASan.getAllocaSizeInBytes(*AI), 0, AI->getAlign().value(), AI, 0,
+        0};
     SVD.push_back(D);
   }