Experimental TBAA support for enum types.
llvm-svn: 116613
diff --git a/clang/lib/CodeGen/CodeGenTBAA.cpp b/clang/lib/CodeGen/CodeGenTBAA.cpp
index f9082fc..99a58a7 100644
--- a/clang/lib/CodeGen/CodeGenTBAA.cpp
+++ b/clang/lib/CodeGen/CodeGenTBAA.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "CodeGenTBAA.h"
+#include "Mangle.h"
#include "clang/AST/ASTContext.h"
#include "llvm/LLVMContext.h"
#include "llvm/Metadata.h"
@@ -19,14 +20,15 @@
using namespace CodeGen;
CodeGenTBAA::CodeGenTBAA(ASTContext &Ctx, llvm::LLVMContext& VMContext,
- const LangOptions &Features)
- : Context(Ctx), VMContext(VMContext), Features(Features), Root(0), Char(0) {
+ const LangOptions &Features, MangleContext &MContext)
+ : Context(Ctx), VMContext(VMContext), Features(Features), MContext(MContext),
+ Root(0), Char(0) {
}
CodeGenTBAA::~CodeGenTBAA() {
}
-llvm::MDNode *CodeGenTBAA::getTBAAInfoForNamedType(const char *NameStr,
+llvm::MDNode *CodeGenTBAA::getTBAAInfoForNamedType(llvm::StringRef NameStr,
llvm::MDNode *Parent) {
llvm::Value *Ops[] = {
llvm::MDString::get(VMContext, NameStr),
@@ -85,6 +87,32 @@
if (Ty->isPointerType())
return MetadataCache[Ty] = getTBAAInfoForNamedType("TBAA.pointer", Char);
+ // Enum types are distinct types. In C++ they have "underlying types",
+ // however they aren't related for TBAA.
+ if (const EnumType *ETy = dyn_cast<EnumType>(Ty)) {
+ // In C mode, two anonymous enums are compatible iff their members
+ // are the same -- see C99 6.2.7p1. For now, be conservative. We could
+ // theoretically implement this by combining information about all the
+ // members into a single identifying MDNode.
+ if (!Features.CPlusPlus &&
+ ETy->getDecl()->getTypedefForAnonDecl())
+ return MetadataCache[Ty] = Char;
+
+ // In C++ mode, types have linkage, so we can rely on the ODR and
+ // on their mangled names, if they're external.
+ // TODO: Is there a way to get a program-wide unique name for a
+ // decl with local linkage or no linkage?
+ if (Features.CPlusPlus &&
+ ETy->getDecl()->getLinkage() != ExternalLinkage)
+ return MetadataCache[Ty] = Char;
+
+ // TODO: This is using the RTTI name. Is there a better way to get
+ // a unique string for a type?
+ llvm::SmallString<256> OutName;
+ MContext.mangleCXXRTTIName(QualType(ETy, 0), OutName);
+ return MetadataCache[Ty] = getTBAAInfoForNamedType(OutName, Char);
+ }
+
// For now, handle any other kind of type conservatively.
return MetadataCache[Ty] = Char;
}