TBAA: use the same format for scalar TBAA and struct-path aware TBAA.
An updated version of r191586 with bug fix.
Struct-path aware TBAA generates tags to specify the access path,
while scalar TBAA only generates tags to scalar types.
We should not generate a TBAA tag with null being the first field. When
a TBAA type node is null, the tag should be null too. Make sure we
don't decorate an instruction with a null TBAA tag.
Added a testing case for the bug reported by Richard with -relaxed-aliasing
and -fsanitizer=thread.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192145 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenTBAA.cpp b/lib/CodeGen/CodeGenTBAA.cpp
index f104c2f..11e376f 100644
--- a/lib/CodeGen/CodeGenTBAA.cpp
+++ b/lib/CodeGen/CodeGenTBAA.cpp
@@ -50,16 +50,11 @@
return Root;
}
-// For struct-path aware TBAA, the scalar type has the same format as
-// the struct type: name, offset, pointer to another node in the type DAG.
-// For scalar TBAA, the scalar type is the same as the scalar tag:
-// name and a parent pointer.
+// For both scalar TBAA and struct-path aware TBAA, the scalar type has the
+// same format: name, parent node, and offset.
llvm::MDNode *CodeGenTBAA::createTBAAScalarType(StringRef Name,
llvm::MDNode *Parent) {
- if (CodeGenOpts.StructPathTBAA)
- return MDHelper.createTBAAScalarTypeNode(Name, Parent);
- else
- return MDHelper.createTBAANode(Name, Parent);
+ return MDHelper.createTBAAScalarTypeNode(Name, Parent);
}
llvm::MDNode *CodeGenTBAA::getChar() {
@@ -91,7 +86,7 @@
llvm::MDNode *
CodeGenTBAA::getTBAAInfo(QualType QTy) {
- // At -O0 TBAA is not emitted for regular types.
+ // At -O0 or relaxed aliasing, TBAA is not emitted for regular types.
if (CodeGenOpts.OptimizationLevel == 0 || CodeGenOpts.RelaxedAliasing)
return NULL;
@@ -211,8 +206,7 @@
uint64_t Offset = BaseOffset;
uint64_t Size = Context.getTypeSizeInChars(QTy).getQuantity();
llvm::MDNode *TBAAInfo = MayAlias ? getChar() : getTBAAInfo(QTy);
- llvm::MDNode *TBAATag = CodeGenOpts.StructPathTBAA ?
- getTBAAScalarTagInfo(TBAAInfo) : TBAAInfo;
+ llvm::MDNode *TBAATag = getTBAAScalarTagInfo(TBAAInfo);
Fields.push_back(llvm::MDBuilder::TBAAStructField(Offset, Size, TBAATag));
return true;
}
@@ -293,11 +287,15 @@
return StructMetadataCache[Ty] = NULL;
}
+/// Return a TBAA tag node for both scalar TBAA and struct-path aware TBAA.
llvm::MDNode *
CodeGenTBAA::getTBAAStructTagInfo(QualType BaseQTy, llvm::MDNode *AccessNode,
uint64_t Offset) {
+ if (!AccessNode)
+ return NULL;
+
if (!CodeGenOpts.StructPathTBAA)
- return AccessNode;
+ return getTBAAScalarTagInfo(AccessNode);
const Type *BTy = Context.getCanonicalType(BaseQTy).getTypePtr();
TBAAPathTag PathTag = TBAAPathTag(BTy, AccessNode, Offset);
@@ -317,6 +315,8 @@
llvm::MDNode *
CodeGenTBAA::getTBAAScalarTagInfo(llvm::MDNode *AccessNode) {
+ if (!AccessNode)
+ return NULL;
if (llvm::MDNode *N = ScalarTagMetadataCache[AccessNode])
return N;