Struct-path aware TBAA: uniformize scalar tag and path tag.
For struct-path aware TBAA, we used to use scalar type node as the scalar tag,
which has an incompatible format with the struct path tag. We now use the same
format: base type, access type and offset.
We also uniformize the scalar type node and the struct type node: name, a list
of pairs (offset + pointer to MDNode). For scalar type, we have a single pair.
These are to make implementaiton of aliasing rules easier.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179335 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index fe0d070..4d72dc1 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1175,7 +1175,7 @@
if (TBAAInfo) {
llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
TBAAOffset);
- CGM.DecorateInstruction(Load, TBAAPath);
+ CGM.DecorateInstruction(Load, TBAAPath, false/*ConvertTypeToTag*/);
}
if ((SanOpts->Bool && hasBooleanRepresentation(Ty)) ||
@@ -1289,7 +1289,7 @@
if (TBAAInfo) {
llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
TBAAOffset);
- CGM.DecorateInstruction(Store, TBAAPath);
+ CGM.DecorateInstruction(Store, TBAAPath, false/*ConvertTypeToTag*/);
}
}
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index e8e3d1a..4126bea 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -242,9 +242,18 @@
return TBAA->getTBAAStructTagInfo(BaseTy, AccessN, O);
}
+/// Decorate the instruction with a TBAA tag. For scalar TBAA, the tag
+/// is the same as the type. For struct-path aware TBAA, the tag
+/// is different from the type: base type, access type and offset.
+/// When ConvertTypeToTag is true, we create a tag based on the scalar type.
void CodeGenModule::DecorateInstruction(llvm::Instruction *Inst,
- llvm::MDNode *TBAAInfo) {
- Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo);
+ llvm::MDNode *TBAAInfo,
+ bool ConvertTypeToTag) {
+ if (ConvertTypeToTag && TBAA && CodeGenOpts.StructPathTBAA)
+ Inst->setMetadata(llvm::LLVMContext::MD_tbaa,
+ TBAA->getTBAAScalarTagInfo(TBAAInfo));
+ else
+ Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo);
}
bool CodeGenModule::isTargetDarwin() const {
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 6bc4456..f8b0971 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -519,8 +519,13 @@
bool isPaddedAtomicType(QualType type);
bool isPaddedAtomicType(const AtomicType *type);
- static void DecorateInstruction(llvm::Instruction *Inst,
- llvm::MDNode *TBAAInfo);
+ /// Decorate the instruction with a TBAA tag. For scalar TBAA, the tag
+ /// is the same as the type. For struct-path aware TBAA, the tag
+ /// is different from the type: base type, access type and offset.
+ /// When ConvertTypeToTag is true, we create a tag based on the scalar type.
+ void DecorateInstruction(llvm::Instruction *Inst,
+ llvm::MDNode *TBAAInfo,
+ bool ConvertTypeToTag = true);
/// getSize - Emit the given number of characters as a value of type size_t.
llvm::ConstantInt *getSize(CharUnits numChars);
diff --git a/lib/CodeGen/CodeGenTBAA.cpp b/lib/CodeGen/CodeGenTBAA.cpp
index 7e4d34a..bb1ebda 100644
--- a/lib/CodeGen/CodeGenTBAA.cpp
+++ b/lib/CodeGen/CodeGenTBAA.cpp
@@ -50,13 +50,25 @@
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.
+llvm::MDNode *CodeGenTBAA::createTBAAScalarType(StringRef Name,
+ llvm::MDNode *Parent) {
+ if (CodeGenOpts.StructPathTBAA)
+ return MDHelper.createTBAAScalarTypeNode(Name, 0, Parent);
+ else
+ return MDHelper.createTBAANode(Name, Parent);
+}
+
llvm::MDNode *CodeGenTBAA::getChar() {
// Define the root of the tree for user-accessible memory. C and C++
// give special powers to char and certain similar types. However,
// these special powers only cover user-accessible memory, and doesn't
// include things like vtables.
if (!Char)
- Char = MDHelper.createTBAANode("omnipotent char", getRoot());
+ Char = createTBAAScalarType("omnipotent char", getRoot());
return Char;
}
@@ -124,7 +136,7 @@
// "underlying types".
default:
return MetadataCache[Ty] =
- MDHelper.createTBAANode(BTy->getName(Features), getChar());
+ createTBAAScalarType(BTy->getName(Features), getChar());
}
}
@@ -132,8 +144,8 @@
// TODO: Implement C++'s type "similarity" and consider dis-"similar"
// pointers distinct.
if (Ty->isPointerType())
- return MetadataCache[Ty] = MDHelper.createTBAANode("any pointer",
- getChar());
+ return MetadataCache[Ty] = createTBAAScalarType("any pointer",
+ getChar());
// Enum types are distinct types. In C++ they have "underlying types",
// however they aren't related for TBAA.
@@ -160,7 +172,7 @@
llvm::raw_svector_ostream Out(OutName);
MContext.mangleCXXRTTIName(QualType(ETy, 0), Out);
Out.flush();
- return MetadataCache[Ty] = MDHelper.createTBAANode(OutName, getChar());
+ return MetadataCache[Ty] = createTBAAScalarType(OutName, getChar());
}
// For now, handle any other kind of type conservatively.
@@ -168,7 +180,7 @@
}
llvm::MDNode *CodeGenTBAA::getTBAAInfoForVTablePtr() {
- return MDHelper.createTBAANode("vtable pointer", getRoot());
+ return createTBAAScalarType("vtable pointer", getRoot());
}
bool
@@ -252,10 +264,6 @@
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
SmallVector <std::pair<uint64_t, llvm::MDNode*>, 4> Fields;
- // To reduce the size of MDNode for a given struct type, we only output
- // once for all the fields with the same scalar types.
- // Offsets for scalar fields in the type DAG are not used.
- llvm::SmallSet <llvm::MDNode*, 4> ScalarFieldTypes;
unsigned idx = 0;
for (RecordDecl::field_iterator i = RD->field_begin(),
e = RD->field_end(); i != e; ++i, ++idx) {
@@ -263,13 +271,8 @@
llvm::MDNode *FieldNode;
if (isTBAAPathStruct(FieldQTy))
FieldNode = getTBAAStructTypeInfo(FieldQTy);
- else {
+ else
FieldNode = getTBAAInfo(FieldQTy);
- // Ignore this field if the type already exists.
- if (ScalarFieldTypes.count(FieldNode))
- continue;
- ScalarFieldTypes.insert(FieldNode);
- }
if (!FieldNode)
return StructTypeMetadataCache[Ty] = NULL;
Fields.push_back(std::make_pair(
@@ -305,8 +308,18 @@
if (isTBAAPathStruct(BaseQTy))
BNode = getTBAAStructTypeInfo(BaseQTy);
if (!BNode)
- return StructTagMetadataCache[PathTag] = AccessNode;
+ return StructTagMetadataCache[PathTag] =
+ MDHelper.createTBAAStructTagNode(AccessNode, AccessNode, 0);
return StructTagMetadataCache[PathTag] =
MDHelper.createTBAAStructTagNode(BNode, AccessNode, Offset);
}
+
+llvm::MDNode *
+CodeGenTBAA::getTBAAScalarTagInfo(llvm::MDNode *AccessNode) {
+ if (llvm::MDNode *N = ScalarTagMetadataCache[AccessNode])
+ return N;
+
+ return ScalarTagMetadataCache[AccessNode] =
+ MDHelper.createTBAAStructTagNode(AccessNode, AccessNode, 0);
+}
diff --git a/lib/CodeGen/CodeGenTBAA.h b/lib/CodeGen/CodeGenTBAA.h
index 9ddc3aa..f0c9e06 100644
--- a/lib/CodeGen/CodeGenTBAA.h
+++ b/lib/CodeGen/CodeGenTBAA.h
@@ -61,6 +61,8 @@
llvm::DenseMap<const Type *, llvm::MDNode *> StructTypeMetadataCache;
/// This maps TBAAPathTags to a tag node.
llvm::DenseMap<TBAAPathTag, llvm::MDNode *> StructTagMetadataCache;
+ /// This maps a scalar type to a scalar tag node.
+ llvm::DenseMap<const llvm::MDNode *, llvm::MDNode *> ScalarTagMetadataCache;
/// StructMetadataCache - This maps clang::Types to llvm::MDNodes describing
/// them for struct assignments.
@@ -84,6 +86,11 @@
SmallVectorImpl<llvm::MDBuilder::TBAAStructField> &Fields,
bool MayAlias);
+ /// A wrapper function to create a scalar type. 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.
+ llvm::MDNode *createTBAAScalarType(StringRef Name, llvm::MDNode *Parent);
+
public:
CodeGenTBAA(ASTContext &Ctx, llvm::LLVMContext &VMContext,
const CodeGenOptions &CGO,
@@ -105,10 +112,13 @@
/// Get the MDNode in the type DAG for given struct type QType.
llvm::MDNode *getTBAAStructTypeInfo(QualType QType);
- /// Get the tag MDNode for a given base type, the actual sclar access MDNode
+ /// Get the tag MDNode for a given base type, the actual scalar access MDNode
/// and offset into the base type.
llvm::MDNode *getTBAAStructTagInfo(QualType BaseQType,
llvm::MDNode *AccessNode, uint64_t Offset);
+
+ /// Get the sclar tag MDNode for a given scalar type.
+ llvm::MDNode *getTBAAScalarTagInfo(llvm::MDNode *AccessNode);
};
} // end namespace CodeGen