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Closed by commit rGf975ae4867d1: [CodeGen][typeid] Emit typeinfo directly if
type is known at compile-time (authored by zequanwu).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D87425/new/
https://reviews.llvm.org/D87425
Files:
clang/include/clang/AST/ExprCXX.h
clang/lib/AST/ExprCXX.cpp
clang/lib/CodeGen/CGExprCXX.cpp
clang/test/CodeGenCXX/microsoft-abi-typeid.cpp
Index: clang/test/CodeGenCXX/microsoft-abi-typeid.cpp
===================================================================
--- clang/test/CodeGenCXX/microsoft-abi-typeid.cpp
+++ clang/test/CodeGenCXX/microsoft-abi-typeid.cpp
@@ -46,9 +46,11 @@
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 {
Index: clang/lib/CodeGen/CGExprCXX.cpp
===================================================================
--- clang/lib/CodeGen/CGExprCXX.cpp
+++ clang/lib/CodeGen/CGExprCXX.cpp
@@ -2199,7 +2199,8 @@
// 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);
Index: clang/lib/AST/ExprCXX.cpp
===================================================================
--- clang/lib/AST/ExprCXX.cpp
+++ clang/lib/AST/ExprCXX.cpp
@@ -146,6 +146,18 @@
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;
Index: clang/include/clang/AST/ExprCXX.h
===================================================================
--- clang/include/clang/AST/ExprCXX.h
+++ clang/include/clang/AST/ExprCXX.h
@@ -858,6 +858,10 @@
/// 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
Index: clang/test/CodeGenCXX/microsoft-abi-typeid.cpp
===================================================================
--- clang/test/CodeGenCXX/microsoft-abi-typeid.cpp
+++ clang/test/CodeGenCXX/microsoft-abi-typeid.cpp
@@ -46,9 +46,11 @@
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 {
Index: clang/lib/CodeGen/CGExprCXX.cpp
===================================================================
--- clang/lib/CodeGen/CGExprCXX.cpp
+++ clang/lib/CodeGen/CGExprCXX.cpp
@@ -2199,7 +2199,8 @@
// 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);
Index: clang/lib/AST/ExprCXX.cpp
===================================================================
--- clang/lib/AST/ExprCXX.cpp
+++ clang/lib/AST/ExprCXX.cpp
@@ -146,6 +146,18 @@
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;
Index: clang/include/clang/AST/ExprCXX.h
===================================================================
--- clang/include/clang/AST/ExprCXX.h
+++ clang/include/clang/AST/ExprCXX.h
@@ -858,6 +858,10 @@
/// 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
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