Add basic support for adding !tbaa.struct metadata on llvm.memcpy calls for
struct assignment.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164853 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenTBAA.cpp b/lib/CodeGen/CodeGenTBAA.cpp
index bab60af..d9004a0 100644
--- a/lib/CodeGen/CodeGenTBAA.cpp
+++ b/lib/CodeGen/CodeGenTBAA.cpp
@@ -17,6 +17,7 @@
#include "CodeGenTBAA.h"
#include "clang/AST/ASTContext.h"
+#include "clang/AST/RecordLayout.h"
#include "clang/AST/Mangle.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/LLVMContext.h"
@@ -167,3 +168,59 @@
llvm::MDNode *CodeGenTBAA::getTBAAInfoForVTablePtr() {
return MDHelper.createTBAANode("vtable pointer", getRoot());
}
+
+bool
+CodeGenTBAA::CollectFields(uint64_t BaseOffset,
+ QualType QTy,
+ SmallVectorImpl<llvm::MDBuilder::TBAAStructField> &
+ Fields,
+ bool MayAlias) {
+ /* Things not handled yet include: C++ base classes, bitfields, */
+
+ if (const RecordType *TTy = QTy->getAs<RecordType>()) {
+ const RecordDecl *RD = TTy->getDecl()->getDefinition();
+ if (RD->hasFlexibleArrayMember())
+ return false;
+
+ // TODO: Handle C++ base classes.
+ if (const CXXRecordDecl *Decl = dyn_cast<CXXRecordDecl>(RD))
+ if (Decl->bases_begin() != Decl->bases_end())
+ return false;
+
+ const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
+
+ unsigned idx = 0;
+ for (RecordDecl::field_iterator i = RD->field_begin(),
+ e = RD->field_end(); i != e; ++i, ++idx) {
+ uint64_t Offset = BaseOffset +
+ Layout.getFieldOffset(idx) / Context.getCharWidth();
+ QualType FieldQTy = i->getType();
+ if (!CollectFields(Offset, FieldQTy, Fields,
+ MayAlias || TypeHasMayAlias(FieldQTy)))
+ return false;
+ }
+ return true;
+ }
+
+ /* Otherwise, treat whatever it is as a field. */
+ uint64_t Offset = BaseOffset;
+ uint64_t Size = Context.getTypeSizeInChars(QTy).getQuantity();
+ llvm::MDNode *TBAAInfo = MayAlias ? getChar() : getTBAAInfo(QTy);
+ Fields.push_back(llvm::MDBuilder::TBAAStructField(Offset, Size, TBAAInfo));
+ return true;
+}
+
+llvm::MDNode *
+CodeGenTBAA::getTBAAStructInfo(QualType QTy) {
+ const Type *Ty = Context.getCanonicalType(QTy).getTypePtr();
+
+ if (llvm::MDNode *N = StructMetadataCache[Ty])
+ return N;
+
+ SmallVector<llvm::MDBuilder::TBAAStructField, 4> Fields;
+ if (CollectFields(0, QTy, Fields, TypeHasMayAlias(QTy)))
+ return MDHelper.createTBAAStructNode(Fields);
+
+ // For now, handle any other kind of type conservatively.
+ return StructMetadataCache[Ty] = NULL;
+}