Initial support for struct-path aware TBAA.
Added TBAABaseType and TBAAOffset in LValue. These two fields are initialized to
the actual type and 0, and are updated in EmitLValueForField.
Path-aware TBAA tags are enabled for EmitLoadOfScalar and EmitStoreOfScalar.
Added command line option -struct-path-tbaa.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178797 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 9bfaacb..2f5186d 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1044,7 +1044,8 @@
llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue) {
return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(),
lvalue.getAlignment().getQuantity(),
- lvalue.getType(), lvalue.getTBAAInfo());
+ lvalue.getType(), lvalue.getTBAAInfo(),
+ lvalue.getTBAABaseType(), lvalue.getTBAAOffset());
}
static bool hasBooleanRepresentation(QualType Ty) {
@@ -1106,7 +1107,9 @@
llvm::Value *CodeGenFunction::EmitLoadOfScalar(llvm::Value *Addr, bool Volatile,
unsigned Alignment, QualType Ty,
- llvm::MDNode *TBAAInfo) {
+ llvm::MDNode *TBAAInfo,
+ QualType TBAABaseType,
+ uint64_t TBAAOffset) {
// For better performance, handle vector loads differently.
if (Ty->isVectorType()) {
llvm::Value *V;
@@ -1158,8 +1161,11 @@
Load->setVolatile(true);
if (Alignment)
Load->setAlignment(Alignment);
- if (TBAAInfo)
- CGM.DecorateInstruction(Load, TBAAInfo);
+ if (TBAAInfo) {
+ llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
+ TBAAOffset);
+ CGM.DecorateInstruction(Load, TBAAPath);
+ }
if ((SanOpts->Bool && hasBooleanRepresentation(Ty)) ||
(SanOpts->Enum && Ty->getAs<EnumType>())) {
@@ -1217,7 +1223,8 @@
bool Volatile, unsigned Alignment,
QualType Ty,
llvm::MDNode *TBAAInfo,
- bool isInit) {
+ bool isInit, QualType TBAABaseType,
+ uint64_t TBAAOffset) {
// Handle vectors differently to get better performance.
if (Ty->isVectorType()) {
@@ -1268,15 +1275,19 @@
llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
if (Alignment)
Store->setAlignment(Alignment);
- if (TBAAInfo)
- CGM.DecorateInstruction(Store, TBAAInfo);
+ if (TBAAInfo) {
+ llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
+ TBAAOffset);
+ CGM.DecorateInstruction(Store, TBAAPath);
+ }
}
void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue,
bool isInit) {
EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
lvalue.getAlignment().getQuantity(), lvalue.getType(),
- lvalue.getTBAAInfo(), isInit);
+ lvalue.getTBAAInfo(), isInit, lvalue.getTBAABaseType(),
+ lvalue.getTBAAOffset());
}
/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
@@ -2494,9 +2505,12 @@
llvm::Value *addr = base.getAddress();
unsigned cvr = base.getVRQualifiers();
+ bool TBAAPath = CGM.getCodeGenOpts().StructPathTBAA;
if (rec->isUnion()) {
// For unions, there is no pointer adjustment.
assert(!type->isReferenceType() && "union has reference member");
+ // TODO: handle path-aware TBAA for union.
+ TBAAPath = false;
} else {
// For structs, we GEP to the field that the record layout suggests.
unsigned idx = CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
@@ -2508,6 +2522,8 @@
if (cvr & Qualifiers::Volatile) load->setVolatile(true);
load->setAlignment(alignment.getQuantity());
+ // Loading the reference will disable path-aware TBAA.
+ TBAAPath = false;
if (CGM.shouldUseTBAA()) {
llvm::MDNode *tbaa;
if (mayAlias)
@@ -2541,6 +2557,16 @@
LValue LV = MakeAddrLValue(addr, type, alignment);
LV.getQuals().addCVRQualifiers(cvr);
+ if (TBAAPath) {
+ const ASTRecordLayout &Layout =
+ getContext().getASTRecordLayout(field->getParent());
+ // Set the base type to be the base type of the base LValue and
+ // update offset to be relative to the base type.
+ LV.setTBAABaseType(base.getTBAABaseType());
+ LV.setTBAAOffset(base.getTBAAOffset() +
+ Layout.getFieldOffset(field->getFieldIndex()) /
+ getContext().getCharWidth());
+ }
// __weak attribute on a field is ignored.
if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)