/// evaluated, per C++11 [expr.typeid]p3.
bool isPotentiallyEvaluated() const;
+ /// Best-effort check if the expression operand refers to a most derived
+ /// object. This is not a strong guarantee.
+ bool isMostDerived(ASTContext &Context) const;
+
bool isTypeOperand() const { return Operand.is<TypeSourceInfo *>(); }
/// Retrieves the type operand of this typeid() expression after
return false;
}
+bool CXXTypeidExpr::isMostDerived(ASTContext &Context) const {
+ assert(!isTypeOperand() && "Cannot call isMostDerived for typeid(type)");
+ const Expr *E = getExprOperand()->IgnoreParenNoopCasts(Context);
+ if (const auto *DRE = dyn_cast<DeclRefExpr>(E)) {
+ QualType Ty = DRE->getDecl()->getType();
+ if (!Ty->isPointerType() && !Ty->isReferenceType())
+ return true;
+ }
+
+ return false;
+}
+
QualType CXXTypeidExpr::getTypeOperand(ASTContext &Context) const {
assert(isTypeOperand() && "Cannot call getTypeOperand for typeid(expr)");
Qualifiers Quals;
// polymorphic class type, the result refers to a std::type_info object
// representing the type of the most derived object (that is, the dynamic
// type) to which the glvalue refers.
- if (E->isPotentiallyEvaluated())
+ // If the operand is already most derived object, no need to look up vtable.
+ if (E->isPotentiallyEvaluated() && !E->isMostDerived(getContext()))
return EmitTypeidFromVTable(*this, E->getExprOperand(),
StdTypeInfoPtrTy);
const std::type_info* test5_typeid() { return &typeid(v); }
// CHECK: define dso_local %struct.type_info* @"?test5_typeid@@YAPBUtype_info@@XZ"()
-// CHECK: [[RT:%.*]] = call i8* @__RTtypeid(i8* bitcast (%struct.V* @"?v@@3UV@@A" to i8*))
-// CHECK-NEXT: [[RET:%.*]] = bitcast i8* [[RT]] to %struct.type_info*
-// CHECK-NEXT: ret %struct.type_info* [[RET]]
+// CHECK: ret %struct.type_info* bitcast (%rtti.TypeDescriptor7* @"??_R0?AUV@@@8" to %struct.type_info*)
+
+const std::type_info *test6_typeid() { return &typeid((V &)v); }
+// CHECK: define dso_local %struct.type_info* @"?test6_typeid@@YAPBUtype_info@@XZ"()
+// CHECK: ret %struct.type_info* bitcast (%rtti.TypeDescriptor7* @"??_R0?AUV@@@8" to %struct.type_info*)
namespace PR26329 {
struct Polymorphic {