r360995 - Refactor constant evaluation of typeid(T) to track a symbolic type_info
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Fri May 17 00:06:46 PDT 2019
Author: rsmith
Date: Fri May 17 00:06:46 2019
New Revision: 360995
URL: http://llvm.org/viewvc/llvm-project?rev=360995&view=rev
Log:
Refactor constant evaluation of typeid(T) to track a symbolic type_info
object rather than tracking the originating expression.
This is groundwork for supporting polymorphic typeid expressions. (Note
that this somewhat regresses our support for DR1968, but it turns out
that that never actually worked anyway, at least in non-trivial cases.)
This reinstates r360974, reverted in r360988, with a fix for a
static_assert failure on 32-bit builds: force Type base class to have
8-byte alignment like the rest of Clang's AST nodes.
Modified:
cfe/trunk/include/clang/AST/APValue.h
cfe/trunk/include/clang/AST/Type.h
cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
cfe/trunk/lib/AST/APValue.cpp
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/lib/CodeGen/CGExprConstant.cpp
cfe/trunk/lib/Sema/SemaTemplate.cpp
cfe/trunk/test/CXX/drs/dr19xx.cpp
cfe/trunk/test/Parser/MicrosoftExtensions.cpp
cfe/trunk/test/SemaCXX/builtin-constant-p.cpp
cfe/trunk/test/SemaCXX/typeid.cpp
cfe/trunk/www/cxx_dr_status.html
Modified: cfe/trunk/include/clang/AST/APValue.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/APValue.h?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/APValue.h (original)
+++ cfe/trunk/include/clang/AST/APValue.h Fri May 17 00:06:46 2019
@@ -24,14 +24,52 @@ namespace clang {
class AddrLabelExpr;
class ASTContext;
class CharUnits;
+ class CXXRecordDecl;
+ class Decl;
class DiagnosticBuilder;
class Expr;
class FieldDecl;
- class Decl;
+ struct PrintingPolicy;
+ class Type;
class ValueDecl;
- class CXXRecordDecl;
- class QualType;
+/// Symbolic representation of typeid(T) for some type T.
+class TypeInfoLValue {
+ const Type *T;
+
+public:
+ TypeInfoLValue() : T() {}
+ explicit TypeInfoLValue(const Type *T);
+
+ const Type *getType() const { return T; }
+ explicit operator bool() const { return T; }
+
+ void *getOpaqueValue() { return const_cast<Type*>(T); }
+ static TypeInfoLValue getFromOpaqueValue(void *Value) {
+ TypeInfoLValue V;
+ V.T = reinterpret_cast<const Type*>(Value);
+ return V;
+ }
+
+ void print(llvm::raw_ostream &Out, const PrintingPolicy &Policy) const;
+};
+}
+
+namespace llvm {
+template<> struct PointerLikeTypeTraits<clang::TypeInfoLValue> {
+ static void *getAsVoidPointer(clang::TypeInfoLValue V) {
+ return V.getOpaqueValue();
+ }
+ static clang::TypeInfoLValue getFromVoidPointer(void *P) {
+ return clang::TypeInfoLValue::getFromOpaqueValue(P);
+ }
+ // Validated by static_assert in APValue.cpp; hardcoded to avoid needing
+ // to include Type.h.
+ static constexpr int NumLowBitsAvailable = 3;
+};
+}
+
+namespace clang {
/// APValue - This class implements a discriminated union of [uninitialized]
/// [APSInt] [APFloat], [Complex APSInt] [Complex APFloat], [Expr + Offset],
/// [Vector: N * APValue], [Array: N * APValue]
@@ -56,14 +94,14 @@ public:
};
class LValueBase {
- public:
- typedef llvm::PointerUnion<const ValueDecl *, const Expr *> PtrTy;
-
- LValueBase() : CallIndex(0), Version(0) {}
+ typedef llvm::PointerUnion<const ValueDecl *, const Expr *, TypeInfoLValue>
+ PtrTy;
- template <class T>
- LValueBase(T P, unsigned I = 0, unsigned V = 0)
- : Ptr(P), CallIndex(I), Version(V) {}
+ public:
+ LValueBase() : Local{} {}
+ LValueBase(const ValueDecl *P, unsigned I = 0, unsigned V = 0);
+ LValueBase(const Expr *P, unsigned I = 0, unsigned V = 0);
+ static LValueBase getTypeInfo(TypeInfoLValue LV, QualType TypeInfo);
template <class T>
bool is() const { return Ptr.is<T>(); }
@@ -78,28 +116,13 @@ public:
bool isNull() const;
- explicit operator bool () const;
-
- PtrTy getPointer() const {
- return Ptr;
- }
-
- unsigned getCallIndex() const {
- return CallIndex;
- }
+ explicit operator bool() const;
- void setCallIndex(unsigned Index) {
- CallIndex = Index;
- }
+ unsigned getCallIndex() const;
+ unsigned getVersion() const;
+ QualType getTypeInfoType() const;
- unsigned getVersion() const {
- return Version;
- }
-
- friend bool operator==(const LValueBase &LHS, const LValueBase &RHS) {
- return LHS.Ptr == RHS.Ptr && LHS.CallIndex == RHS.CallIndex &&
- LHS.Version == RHS.Version;
- }
+ friend bool operator==(const LValueBase &LHS, const LValueBase &RHS);
friend bool operator!=(const LValueBase &LHS, const LValueBase &RHS) {
return !(LHS == RHS);
}
@@ -107,7 +130,14 @@ public:
private:
PtrTy Ptr;
- unsigned CallIndex, Version;
+ struct LocalState {
+ unsigned CallIndex, Version;
+ };
+ union {
+ LocalState Local;
+ /// The type std::type_info, if this is a TypeInfoLValue.
+ void *TypeInfoType;
+ };
};
/// A FieldDecl or CXXRecordDecl, along with a flag indicating whether we
Modified: cfe/trunk/include/clang/AST/Type.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Type.h?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Type.h (original)
+++ cfe/trunk/include/clang/AST/Type.h Fri May 17 00:06:46 2019
@@ -1411,7 +1411,7 @@ enum class AutoTypeKeyword {
///
/// Types, once created, are immutable.
///
-class Type : public ExtQualsTypeCommonBase {
+class alignas(8) Type : public ExtQualsTypeCommonBase {
public:
enum TypeClass {
#define TYPE(Class, Base) Class,
Modified: cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td Fri May 17 00:06:46 2019
@@ -160,6 +160,9 @@ def note_constexpr_access_static_tempora
"dynamic_cast of}0 temporary "
"is not allowed in a constant expression outside the expression that "
"created the temporary">;
+def note_constexpr_access_unreadable_object : Note<
+ "%select{read of|assignment to|increment of|decrement of|member call on|"
+ "dynamic_cast of}0 object '%1' whose value is not known">;
def note_constexpr_modify_global : Note<
"a constant expression cannot modify an object that is visible outside "
"that expression">;
Modified: cfe/trunk/lib/AST/APValue.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/APValue.cpp?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/lib/AST/APValue.cpp (original)
+++ cfe/trunk/lib/AST/APValue.cpp Fri May 17 00:06:46 2019
@@ -20,6 +20,61 @@
#include "llvm/Support/raw_ostream.h"
using namespace clang;
+/// The identity of a type_info object depends on the canonical unqualified
+/// type only.
+TypeInfoLValue::TypeInfoLValue(const Type *T)
+ : T(T->getCanonicalTypeUnqualified().getTypePtr()) {}
+
+void TypeInfoLValue::print(llvm::raw_ostream &Out,
+ const PrintingPolicy &Policy) const {
+ Out << "typeid(";
+ QualType(getType(), 0).print(Out, Policy);
+ Out << ")";
+}
+
+static_assert(
+ 1 << llvm::PointerLikeTypeTraits<TypeInfoLValue>::NumLowBitsAvailable <=
+ alignof(const Type *),
+ "Type is insufficiently aligned");
+
+APValue::LValueBase::LValueBase(const ValueDecl *P, unsigned I, unsigned V)
+ : Ptr(P), Local{I, V} {}
+APValue::LValueBase::LValueBase(const Expr *P, unsigned I, unsigned V)
+ : Ptr(P), Local{I, V} {}
+
+APValue::LValueBase APValue::LValueBase::getTypeInfo(TypeInfoLValue LV,
+ QualType TypeInfo) {
+ LValueBase Base;
+ Base.Ptr = LV;
+ Base.TypeInfoType = TypeInfo.getAsOpaquePtr();
+ return Base;
+}
+
+unsigned APValue::LValueBase::getCallIndex() const {
+ return is<TypeInfoLValue>() ? 0 : Local.CallIndex;
+}
+
+unsigned APValue::LValueBase::getVersion() const {
+ return is<TypeInfoLValue>() ? 0 : Local.Version;
+}
+
+QualType APValue::LValueBase::getTypeInfoType() const {
+ assert(is<TypeInfoLValue>() && "not a type_info lvalue");
+ return QualType::getFromOpaquePtr(TypeInfoType);
+}
+
+namespace clang {
+bool operator==(const APValue::LValueBase &LHS,
+ const APValue::LValueBase &RHS) {
+ if (LHS.Ptr != RHS.Ptr)
+ return false;
+ if (LHS.is<TypeInfoLValue>())
+ return true;
+ return LHS.Local.CallIndex == RHS.Local.CallIndex &&
+ LHS.Local.Version == RHS.Local.Version;
+}
+}
+
namespace {
struct LVBase {
APValue::LValueBase Base;
@@ -45,21 +100,19 @@ APValue::LValueBase::operator bool () co
clang::APValue::LValueBase
llvm::DenseMapInfo<clang::APValue::LValueBase>::getEmptyKey() {
return clang::APValue::LValueBase(
- DenseMapInfo<clang::APValue::LValueBase::PtrTy>::getEmptyKey(),
- DenseMapInfo<unsigned>::getEmptyKey(),
- DenseMapInfo<unsigned>::getEmptyKey());
+ DenseMapInfo<const ValueDecl*>::getEmptyKey());
}
clang::APValue::LValueBase
llvm::DenseMapInfo<clang::APValue::LValueBase>::getTombstoneKey() {
return clang::APValue::LValueBase(
- DenseMapInfo<clang::APValue::LValueBase::PtrTy>::getTombstoneKey(),
- DenseMapInfo<unsigned>::getTombstoneKey(),
- DenseMapInfo<unsigned>::getTombstoneKey());
+ DenseMapInfo<const ValueDecl*>::getTombstoneKey());
}
namespace clang {
llvm::hash_code hash_value(const APValue::LValueBase &Base) {
+ if (Base.is<TypeInfoLValue>())
+ return llvm::hash_value(Base.getOpaqueValue());
return llvm::hash_combine(Base.getOpaqueValue(), Base.getCallIndex(),
Base.getVersion());
}
@@ -470,7 +523,9 @@ void APValue::printPretty(raw_ostream &O
if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
Out << *VD;
- else {
+ else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
+ TI.print(Out, Ctx.getPrintingPolicy());
+ } else {
assert(Base.get<const Expr *>() != nullptr &&
"Expecting non-null Expr");
Base.get<const Expr*>()->printPretty(Out, nullptr,
@@ -495,6 +550,9 @@ void APValue::printPretty(raw_ostream &O
if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
Out << *VD;
ElemTy = VD->getType();
+ } else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
+ TI.print(Out, Ctx.getPrintingPolicy());
+ ElemTy = Base.getTypeInfoType();
} else {
const Expr *E = Base.get<const Expr*>();
assert(E != nullptr && "Expecting non-null Expr");
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Fri May 17 00:06:46 2019
@@ -87,6 +87,9 @@ namespace {
return D->getType();
}
+ if (TypeInfoLValue TI = B.dyn_cast<TypeInfoLValue>())
+ return B.getTypeInfoType();
+
const Expr *Base = B.get<const Expr*>();
// For a materialized temporary, the type of the temporary we materialized
@@ -1783,6 +1786,9 @@ static bool IsGlobalLValue(APValue::LVal
return isa<FunctionDecl>(D);
}
+ if (B.is<TypeInfoLValue>())
+ return true;
+
const Expr *E = B.get<const Expr*>();
switch (E->getStmtClass()) {
default:
@@ -1800,7 +1806,6 @@ static bool IsGlobalLValue(APValue::LVal
case Expr::PredefinedExprClass:
case Expr::ObjCStringLiteralClass:
case Expr::ObjCEncodeExprClass:
- case Expr::CXXTypeidExprClass:
case Expr::CXXUuidofExprClass:
return true;
case Expr::ObjCBoxedExprClass:
@@ -1878,9 +1883,9 @@ static void NoteLValueLocation(EvalInfo
const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
if (VD)
Info.Note(VD->getLocation(), diag::note_declared_at);
- else
- Info.Note(Base.get<const Expr*>()->getExprLoc(),
- diag::note_constexpr_temporary_here);
+ else if (const Expr *E = Base.dyn_cast<const Expr*>())
+ Info.Note(E->getExprLoc(), diag::note_constexpr_temporary_here);
+ // We have no information to show for a typeid(T) object.
}
/// Check that this reference or pointer core constant expression is a valid
@@ -3404,7 +3409,7 @@ static CompleteObject findCompleteObject
if (!Frame) {
if (const MaterializeTemporaryExpr *MTE =
- dyn_cast<MaterializeTemporaryExpr>(Base)) {
+ dyn_cast_or_null<MaterializeTemporaryExpr>(Base)) {
assert(MTE->getStorageDuration() == SD_Static &&
"should have a frame for a non-global materialized temporary");
@@ -3439,7 +3444,13 @@ static CompleteObject findCompleteObject
} else {
if (!IsAccess)
return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
- Info.FFDiag(E);
+ APValue Val;
+ LVal.moveInto(Val);
+ Info.FFDiag(E, diag::note_constexpr_access_unreadable_object)
+ << AK
+ << Val.getAsString(Info.Ctx,
+ Info.Ctx.getLValueReferenceType(LValType));
+ NoteLValueLocation(Info, LVal.Base);
return CompleteObject();
}
} else {
@@ -5777,13 +5788,13 @@ public:
// - Literals
// * CompoundLiteralExpr in C (and in global scope in C++)
// * StringLiteral
-// * CXXTypeidExpr
// * PredefinedExpr
// * ObjCStringLiteralExpr
// * ObjCEncodeExpr
// * AddrLabelExpr
// * BlockExpr
// * CallExpr for a MakeStringConstant builtin
+// - typeid(T) expressions, as TypeInfoLValues
// - Locals and temporaries
// * MaterializeTemporaryExpr
// * Any Expr, with a CallIndex indicating the function in which the temporary
@@ -6018,8 +6029,14 @@ LValueExprEvaluator::VisitCompoundLitera
}
bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
- if (!E->isPotentiallyEvaluated())
- return Success(E);
+ if (!E->isPotentiallyEvaluated()) {
+ TypeInfoLValue TypeInfo;
+ if (E->isTypeOperand())
+ TypeInfo = TypeInfoLValue(E->getTypeOperand(Info.Ctx).getTypePtr());
+ else
+ TypeInfo = TypeInfoLValue(E->getExprOperand()->getType().getTypePtr());
+ return Success(APValue::LValueBase::getTypeInfo(TypeInfo, E->getType()));
+ }
Info.FFDiag(E, diag::note_constexpr_typeid_polymorphic)
<< E->getExprOperand()->getType()
@@ -6615,9 +6632,11 @@ bool PointerExprEvaluator::VisitBuiltinC
if (const ValueDecl *VD =
OffsetResult.Base.dyn_cast<const ValueDecl*>()) {
BaseAlignment = Info.Ctx.getDeclAlign(VD);
+ } else if (const Expr *E = OffsetResult.Base.dyn_cast<const Expr *>()) {
+ BaseAlignment = GetAlignOfExpr(Info, E, UETT_AlignOf);
} else {
- BaseAlignment = GetAlignOfExpr(
- Info, OffsetResult.Base.get<const Expr *>(), UETT_AlignOf);
+ BaseAlignment = GetAlignOfType(
+ Info, OffsetResult.Base.getTypeInfoType(), UETT_AlignOf);
}
if (BaseAlignment < Align) {
@@ -8335,6 +8354,10 @@ static bool EvaluateBuiltinConstantPForL
if (!isa<StringLiteral>(E))
return false;
return LV.getLValueOffset().isZero();
+ } else if (Base.is<TypeInfoLValue>()) {
+ // Surprisingly, GCC considers __builtin_constant_p(&typeid(int)) to
+ // evaluate to true.
+ return true;
} else {
// Any other base is not constant enough for GCC.
return false;
@@ -8399,6 +8422,8 @@ static QualType getObjectType(APValue::L
} else if (const Expr *E = B.get<const Expr*>()) {
if (isa<CompoundLiteralExpr>(E))
return E->getType();
+ } else if (B.is<TypeInfoLValue>()) {
+ return B.getTypeInfoType();
}
return QualType();
Modified: cfe/trunk/lib/CodeGen/CGExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprConstant.cpp?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprConstant.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprConstant.cpp Fri May 17 00:06:46 2019
@@ -1735,6 +1735,17 @@ ConstantLValueEmitter::tryEmitBase(const
return nullptr;
}
+ // Handle typeid(T).
+ if (TypeInfoLValue TI = base.dyn_cast<TypeInfoLValue>()) {
+ llvm::Type *StdTypeInfoPtrTy =
+ CGM.getTypes().ConvertType(base.getTypeInfoType())->getPointerTo();
+ llvm::Constant *TypeInfo =
+ CGM.GetAddrOfRTTIDescriptor(QualType(TI.getType(), 0));
+ if (TypeInfo->getType() != StdTypeInfoPtrTy)
+ TypeInfo = llvm::ConstantExpr::getBitCast(TypeInfo, StdTypeInfoPtrTy);
+ return TypeInfo;
+ }
+
// Otherwise, it must be an expression.
return Visit(base.get<const Expr*>());
}
Modified: cfe/trunk/lib/Sema/SemaTemplate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplate.cpp?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplate.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplate.cpp Fri May 17 00:06:46 2019
@@ -6424,8 +6424,11 @@ ExprResult Sema::CheckTemplateArgument(N
// -- a string literal
// -- the result of a typeid expression, or
// -- a predefined __func__ variable
- if (auto *E = Value.getLValueBase().dyn_cast<const Expr*>()) {
- if (isa<CXXUuidofExpr>(E)) {
+ APValue::LValueBase Base = Value.getLValueBase();
+ auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
+ if (Base && !VD) {
+ auto *E = Base.dyn_cast<const Expr *>();
+ if (E && isa<CXXUuidofExpr>(E)) {
Converted = TemplateArgument(ArgResult.get()->IgnoreImpCasts());
break;
}
@@ -6433,8 +6436,6 @@ ExprResult Sema::CheckTemplateArgument(N
<< Arg->getSourceRange();
return ExprError();
}
- auto *VD = const_cast<ValueDecl *>(
- Value.getLValueBase().dyn_cast<const ValueDecl *>());
// -- a subobject
if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
VD && VD->getType()->isArrayType() &&
Modified: cfe/trunk/test/CXX/drs/dr19xx.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/drs/dr19xx.cpp?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/test/CXX/drs/dr19xx.cpp (original)
+++ cfe/trunk/test/CXX/drs/dr19xx.cpp Fri May 17 00:06:46 2019
@@ -167,9 +167,14 @@ namespace dr1959 { // dr1959: 3.9
#endif
}
-namespace dr1968 { // dr1968: yes
+namespace dr1968 { // dr1968: no
#if __cplusplus >= 201103L
- static_assert(&typeid(int) == &typeid(int), ""); // expected-error{{not an integral constant expression}}
+ // FIXME: According to DR1968, both of these should be considered
+ // non-constant.
+ static_assert(&typeid(int) == &typeid(int), "");
+
+ constexpr const std::type_info *f() { return &typeid(int); }
+ static_assert(f() == f(), "");
#endif
}
Modified: cfe/trunk/test/Parser/MicrosoftExtensions.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Parser/MicrosoftExtensions.cpp?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/test/Parser/MicrosoftExtensions.cpp (original)
+++ cfe/trunk/test/Parser/MicrosoftExtensions.cpp Fri May 17 00:06:46 2019
@@ -138,6 +138,8 @@ typedef COM_CLASS_TEMPLATE_REF<struct_wi
COM_CLASS_TEMPLATE_REF<int, __uuidof(struct_with_uuid)> good_template_arg;
COM_CLASS_TEMPLATE<int, __uuidof(struct_with_uuid)> bad_template_arg; // expected-error {{non-type template argument of type 'const _GUID' is not a constant expression}}
+// expected-note at -1 {{read of object '__uuidof(struct_with_uuid)' whose value is not known}}
+// expected-note at -2 {{temporary created here}}
namespace PR16911 {
struct __declspec(uuid("{12345678-1234-1234-1234-1234567890aB}")) uuid;
Modified: cfe/trunk/test/SemaCXX/builtin-constant-p.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/builtin-constant-p.cpp?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/builtin-constant-p.cpp (original)
+++ cfe/trunk/test/SemaCXX/builtin-constant-p.cpp Fri May 17 00:06:46 2019
@@ -130,3 +130,8 @@ constexpr int mutate6(bool mutate) {
static_assert(mutate6(false) == 11);
// Mutation of state outside __builtin_constant_p: evaluates to false.
static_assert(mutate6(true) == 10);
+
+// GCC strangely returns true for the address of a type_info object, despite it
+// not being a pointer to the start of a string literal.
+namespace std { struct type_info; }
+static_assert(__builtin_constant_p(&typeid(int)));
Modified: cfe/trunk/test/SemaCXX/typeid.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/typeid.cpp?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/typeid.cpp (original)
+++ cfe/trunk/test/SemaCXX/typeid.cpp Fri May 17 00:06:46 2019
@@ -6,7 +6,7 @@ void f()
}
namespace std {
- class type_info;
+ struct type_info { const char *name; };
}
void g()
@@ -27,3 +27,6 @@ void h(int i) {
typeid(V); // expected-error{{'typeid' of variably modified type 'char [i]'}}
typeid(char [i]); // expected-error{{'typeid' of variably modified type 'char [i]'}}
}
+
+// expected-note at +1 {{read of object 'typeid(int).name' whose value is not known}}
+constexpr const char *name = typeid(int).name; // expected-error {{constant expression}}
Modified: cfe/trunk/www/cxx_dr_status.html
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/www/cxx_dr_status.html?rev=360995&r1=360994&r2=360995&view=diff
==============================================================================
--- cfe/trunk/www/cxx_dr_status.html (original)
+++ cfe/trunk/www/cxx_dr_status.html Fri May 17 00:06:46 2019
@@ -11623,7 +11623,7 @@ and <I>POD class</I></td>
<td><a href="http://wg21.link/cwg1968">1968</a></td>
<td>NAD</td>
<td>Address of <TT>typeid</TT> in constant expressions</td>
- <td class="full" align="center">Yes</td>
+ <td class="none" align="center">No</td>
</tr>
<tr class="open" id="1969">
<td><a href="http://wg21.link/cwg1969">1969</a></td>
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