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SemaExprCXX.cpp
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SemaExprCXX.cpp
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//===--- SemaExprCXX.cpp - Semantic Analysis for Expressions --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// Implements semantic analysis for C++ expressions.
///
//===----------------------------------------------------------------------===//
#include "clang/Sema/SemaInternal.h"
#include "TreeTransform.h"
#include "TypeLocBuilder.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTLambda.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/AlignedAllocation.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaLambda.h"
#include "clang/Sema/TemplateDeduction.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/ErrorHandling.h"
using namespace clang;
using namespace sema;
/// Handle the result of the special case name lookup for inheriting
/// constructor declarations. 'NS::X::X' and 'NS::X<...>::X' are treated as
/// constructor names in member using declarations, even if 'X' is not the
/// name of the corresponding type.
ParsedType Sema::getInheritingConstructorName(CXXScopeSpec &SS,
SourceLocation NameLoc,
IdentifierInfo &Name) {
NestedNameSpecifier *NNS = SS.getScopeRep();
// Convert the nested-name-specifier into a type.
QualType Type;
switch (NNS->getKind()) {
case NestedNameSpecifier::TypeSpec:
case NestedNameSpecifier::TypeSpecWithTemplate:
Type = QualType(NNS->getAsType(), 0);
break;
case NestedNameSpecifier::Identifier:
// Strip off the last layer of the nested-name-specifier and build a
// typename type for it.
assert(NNS->getAsIdentifier() == &Name && "not a constructor name");
Type = Context.getDependentNameType(ETK_None, NNS->getPrefix(),
NNS->getAsIdentifier());
break;
case NestedNameSpecifier::Global:
case NestedNameSpecifier::Super:
case NestedNameSpecifier::Namespace:
case NestedNameSpecifier::NamespaceAlias:
llvm_unreachable("Nested name specifier is not a type for inheriting ctor");
}
// This reference to the type is located entirely at the location of the
// final identifier in the qualified-id.
return CreateParsedType(Type,
Context.getTrivialTypeSourceInfo(Type, NameLoc));
}
ParsedType Sema::getConstructorName(IdentifierInfo &II,
SourceLocation NameLoc,
Scope *S, CXXScopeSpec &SS,
bool EnteringContext) {
CXXRecordDecl *CurClass = getCurrentClass(S, &SS);
assert(CurClass && &II == CurClass->getIdentifier() &&
"not a constructor name");
// When naming a constructor as a member of a dependent context (eg, in a
// friend declaration or an inherited constructor declaration), form an
// unresolved "typename" type.
if (CurClass->isDependentContext() && !EnteringContext && SS.getScopeRep()) {
QualType T = Context.getDependentNameType(ETK_None, SS.getScopeRep(), &II);
return ParsedType::make(T);
}
if (SS.isNotEmpty() && RequireCompleteDeclContext(SS, CurClass))
return ParsedType();
// Find the injected-class-name declaration. Note that we make no attempt to
// diagnose cases where the injected-class-name is shadowed: the only
// declaration that can validly shadow the injected-class-name is a
// non-static data member, and if the class contains both a non-static data
// member and a constructor then it is ill-formed (we check that in
// CheckCompletedCXXClass).
CXXRecordDecl *InjectedClassName = nullptr;
for (NamedDecl *ND : CurClass->lookup(&II)) {
auto *RD = dyn_cast<CXXRecordDecl>(ND);
if (RD && RD->isInjectedClassName()) {
InjectedClassName = RD;
break;
}
}
if (!InjectedClassName) {
if (!CurClass->isInvalidDecl()) {
// FIXME: RequireCompleteDeclContext doesn't check dependent contexts
// properly. Work around it here for now.
Diag(SS.getLastQualifierNameLoc(),
diag::err_incomplete_nested_name_spec) << CurClass << SS.getRange();
}
return ParsedType();
}
QualType T = Context.getTypeDeclType(InjectedClassName);
DiagnoseUseOfDecl(InjectedClassName, NameLoc);
MarkAnyDeclReferenced(NameLoc, InjectedClassName, /*OdrUse=*/false);
return ParsedType::make(T);
}
ParsedType Sema::getDestructorName(SourceLocation TildeLoc,
IdentifierInfo &II,
SourceLocation NameLoc,
Scope *S, CXXScopeSpec &SS,
ParsedType ObjectTypePtr,
bool EnteringContext) {
// Determine where to perform name lookup.
// FIXME: This area of the standard is very messy, and the current
// wording is rather unclear about which scopes we search for the
// destructor name; see core issues 399 and 555. Issue 399 in
// particular shows where the current description of destructor name
// lookup is completely out of line with existing practice, e.g.,
// this appears to be ill-formed:
//
// namespace N {
// template <typename T> struct S {
// ~S();
// };
// }
//
// void f(N::S<int>* s) {
// s->N::S<int>::~S();
// }
//
// See also PR6358 and PR6359.
// For this reason, we're currently only doing the C++03 version of this
// code; the C++0x version has to wait until we get a proper spec.
QualType SearchType;
DeclContext *LookupCtx = nullptr;
bool isDependent = false;
bool LookInScope = false;
if (SS.isInvalid())
return nullptr;
// If we have an object type, it's because we are in a
// pseudo-destructor-expression or a member access expression, and
// we know what type we're looking for.
if (ObjectTypePtr)
SearchType = GetTypeFromParser(ObjectTypePtr);
if (SS.isSet()) {
NestedNameSpecifier *NNS = SS.getScopeRep();
bool AlreadySearched = false;
bool LookAtPrefix = true;
// C++11 [basic.lookup.qual]p6:
// If a pseudo-destructor-name (5.2.4) contains a nested-name-specifier,
// the type-names are looked up as types in the scope designated by the
// nested-name-specifier. Similarly, in a qualified-id of the form:
//
// nested-name-specifier[opt] class-name :: ~ class-name
//
// the second class-name is looked up in the same scope as the first.
//
// Here, we determine whether the code below is permitted to look at the
// prefix of the nested-name-specifier.
DeclContext *DC = computeDeclContext(SS, EnteringContext);
if (DC && DC->isFileContext()) {
AlreadySearched = true;
LookupCtx = DC;
isDependent = false;
} else if (DC && isa<CXXRecordDecl>(DC)) {
LookAtPrefix = false;
LookInScope = true;
}
// The second case from the C++03 rules quoted further above.
NestedNameSpecifier *Prefix = nullptr;
if (AlreadySearched) {
// Nothing left to do.
} else if (LookAtPrefix && (Prefix = NNS->getPrefix())) {
CXXScopeSpec PrefixSS;
PrefixSS.Adopt(NestedNameSpecifierLoc(Prefix, SS.location_data()));
LookupCtx = computeDeclContext(PrefixSS, EnteringContext);
isDependent = isDependentScopeSpecifier(PrefixSS);
} else if (ObjectTypePtr) {
LookupCtx = computeDeclContext(SearchType);
isDependent = SearchType->isDependentType();
} else {
LookupCtx = computeDeclContext(SS, EnteringContext);
isDependent = LookupCtx && LookupCtx->isDependentContext();
}
} else if (ObjectTypePtr) {
// C++ [basic.lookup.classref]p3:
// If the unqualified-id is ~type-name, the type-name is looked up
// in the context of the entire postfix-expression. If the type T
// of the object expression is of a class type C, the type-name is
// also looked up in the scope of class C. At least one of the
// lookups shall find a name that refers to (possibly
// cv-qualified) T.
LookupCtx = computeDeclContext(SearchType);
isDependent = SearchType->isDependentType();
assert((isDependent || !SearchType->isIncompleteType()) &&
"Caller should have completed object type");
LookInScope = true;
} else {
// Perform lookup into the current scope (only).
LookInScope = true;
}
TypeDecl *NonMatchingTypeDecl = nullptr;
LookupResult Found(*this, &II, NameLoc, LookupOrdinaryName);
for (unsigned Step = 0; Step != 2; ++Step) {
// Look for the name first in the computed lookup context (if we
// have one) and, if that fails to find a match, in the scope (if
// we're allowed to look there).
Found.clear();
if (Step == 0 && LookupCtx) {
if (RequireCompleteDeclContext(SS, LookupCtx))
return nullptr;
LookupQualifiedName(Found, LookupCtx);
} else if (Step == 1 && LookInScope && S) {
LookupName(Found, S);
} else {
continue;
}
// FIXME: Should we be suppressing ambiguities here?
if (Found.isAmbiguous())
return nullptr;
if (TypeDecl *Type = Found.getAsSingle<TypeDecl>()) {
QualType T = Context.getTypeDeclType(Type);
MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
if (SearchType.isNull() || SearchType->isDependentType() ||
Context.hasSameUnqualifiedType(T, SearchType)) {
// We found our type!
return CreateParsedType(T,
Context.getTrivialTypeSourceInfo(T, NameLoc));
}
if (!SearchType.isNull())
NonMatchingTypeDecl = Type;
}
// If the name that we found is a class template name, and it is
// the same name as the template name in the last part of the
// nested-name-specifier (if present) or the object type, then
// this is the destructor for that class.
// FIXME: This is a workaround until we get real drafting for core
// issue 399, for which there isn't even an obvious direction.
if (ClassTemplateDecl *Template = Found.getAsSingle<ClassTemplateDecl>()) {
QualType MemberOfType;
if (SS.isSet()) {
if (DeclContext *Ctx = computeDeclContext(SS, EnteringContext)) {
// Figure out the type of the context, if it has one.
if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx))
MemberOfType = Context.getTypeDeclType(Record);
}
}
if (MemberOfType.isNull())
MemberOfType = SearchType;
if (MemberOfType.isNull())
continue;
// We're referring into a class template specialization. If the
// class template we found is the same as the template being
// specialized, we found what we are looking for.
if (const RecordType *Record = MemberOfType->getAs<RecordType>()) {
if (ClassTemplateSpecializationDecl *Spec
= dyn_cast<ClassTemplateSpecializationDecl>(Record->getDecl())) {
if (Spec->getSpecializedTemplate()->getCanonicalDecl() ==
Template->getCanonicalDecl())
return CreateParsedType(
MemberOfType,
Context.getTrivialTypeSourceInfo(MemberOfType, NameLoc));
}
continue;
}
// We're referring to an unresolved class template
// specialization. Determine whether we class template we found
// is the same as the template being specialized or, if we don't
// know which template is being specialized, that it at least
// has the same name.
if (const TemplateSpecializationType *SpecType
= MemberOfType->getAs<TemplateSpecializationType>()) {
TemplateName SpecName = SpecType->getTemplateName();
// The class template we found is the same template being
// specialized.
if (TemplateDecl *SpecTemplate = SpecName.getAsTemplateDecl()) {
if (SpecTemplate->getCanonicalDecl() == Template->getCanonicalDecl())
return CreateParsedType(
MemberOfType,
Context.getTrivialTypeSourceInfo(MemberOfType, NameLoc));
continue;
}
// The class template we found has the same name as the
// (dependent) template name being specialized.
if (DependentTemplateName *DepTemplate
= SpecName.getAsDependentTemplateName()) {
if (DepTemplate->isIdentifier() &&
DepTemplate->getIdentifier() == Template->getIdentifier())
return CreateParsedType(
MemberOfType,
Context.getTrivialTypeSourceInfo(MemberOfType, NameLoc));
continue;
}
}
}
}
if (isDependent) {
// We didn't find our type, but that's okay: it's dependent
// anyway.
// FIXME: What if we have no nested-name-specifier?
QualType T = CheckTypenameType(ETK_None, SourceLocation(),
SS.getWithLocInContext(Context),
II, NameLoc);
return ParsedType::make(T);
}
if (NonMatchingTypeDecl) {
QualType T = Context.getTypeDeclType(NonMatchingTypeDecl);
Diag(NameLoc, diag::err_destructor_expr_type_mismatch)
<< T << SearchType;
Diag(NonMatchingTypeDecl->getLocation(), diag::note_destructor_type_here)
<< T;
} else if (ObjectTypePtr)
Diag(NameLoc, diag::err_ident_in_dtor_not_a_type)
<< &II;
else {
SemaDiagnosticBuilder DtorDiag = Diag(NameLoc,
diag::err_destructor_class_name);
if (S) {
const DeclContext *Ctx = S->getEntity();
if (const CXXRecordDecl *Class = dyn_cast_or_null<CXXRecordDecl>(Ctx))
DtorDiag << FixItHint::CreateReplacement(SourceRange(NameLoc),
Class->getNameAsString());
}
}
return nullptr;
}
ParsedType Sema::getDestructorTypeForDecltype(const DeclSpec &DS,
ParsedType ObjectType) {
if (DS.getTypeSpecType() == DeclSpec::TST_error)
return nullptr;
if (DS.getTypeSpecType() == DeclSpec::TST_decltype_auto) {
Diag(DS.getTypeSpecTypeLoc(), diag::err_decltype_auto_invalid);
return nullptr;
}
assert(DS.getTypeSpecType() == DeclSpec::TST_decltype &&
"unexpected type in getDestructorType");
QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
// If we know the type of the object, check that the correct destructor
// type was named now; we can give better diagnostics this way.
QualType SearchType = GetTypeFromParser(ObjectType);
if (!SearchType.isNull() && !SearchType->isDependentType() &&
!Context.hasSameUnqualifiedType(T, SearchType)) {
Diag(DS.getTypeSpecTypeLoc(), diag::err_destructor_expr_type_mismatch)
<< T << SearchType;
return nullptr;
}
return ParsedType::make(T);
}
bool Sema::checkLiteralOperatorId(const CXXScopeSpec &SS,
const UnqualifiedId &Name) {
assert(Name.getKind() == UnqualifiedIdKind::IK_LiteralOperatorId);
if (!SS.isValid())
return false;
switch (SS.getScopeRep()->getKind()) {
case NestedNameSpecifier::Identifier:
case NestedNameSpecifier::TypeSpec:
case NestedNameSpecifier::TypeSpecWithTemplate:
// Per C++11 [over.literal]p2, literal operators can only be declared at
// namespace scope. Therefore, this unqualified-id cannot name anything.
// Reject it early, because we have no AST representation for this in the
// case where the scope is dependent.
Diag(Name.getBeginLoc(), diag::err_literal_operator_id_outside_namespace)
<< SS.getScopeRep();
return true;
case NestedNameSpecifier::Global:
case NestedNameSpecifier::Super:
case NestedNameSpecifier::Namespace:
case NestedNameSpecifier::NamespaceAlias:
return false;
}
llvm_unreachable("unknown nested name specifier kind");
}
/// Build a C++ typeid expression with a type operand.
ExprResult Sema::BuildCXXTypeId(QualType TypeInfoType,
SourceLocation TypeidLoc,
TypeSourceInfo *Operand,
SourceLocation RParenLoc) {
// C++ [expr.typeid]p4:
// The top-level cv-qualifiers of the lvalue expression or the type-id
// that is the operand of typeid are always ignored.
// If the type of the type-id is a class type or a reference to a class
// type, the class shall be completely-defined.
Qualifiers Quals;
QualType T
= Context.getUnqualifiedArrayType(Operand->getType().getNonReferenceType(),
Quals);
if (T->getAs<RecordType>() &&
RequireCompleteType(TypeidLoc, T, diag::err_incomplete_typeid))
return ExprError();
if (T->isVariablyModifiedType())
return ExprError(Diag(TypeidLoc, diag::err_variably_modified_typeid) << T);
if (CheckQualifiedFunctionForTypeId(T, TypeidLoc))
return ExprError();
return new (Context) CXXTypeidExpr(TypeInfoType.withConst(), Operand,
SourceRange(TypeidLoc, RParenLoc));
}
/// Build a C++ typeid expression with an expression operand.
ExprResult Sema::BuildCXXTypeId(QualType TypeInfoType,
SourceLocation TypeidLoc,
Expr *E,
SourceLocation RParenLoc) {
bool WasEvaluated = false;
if (E && !E->isTypeDependent()) {
if (E->getType()->isPlaceholderType()) {
ExprResult result = CheckPlaceholderExpr(E);
if (result.isInvalid()) return ExprError();
E = result.get();
}
QualType T = E->getType();
if (const RecordType *RecordT = T->getAs<RecordType>()) {
CXXRecordDecl *RecordD = cast<CXXRecordDecl>(RecordT->getDecl());
// C++ [expr.typeid]p3:
// [...] If the type of the expression is a class type, the class
// shall be completely-defined.
if (RequireCompleteType(TypeidLoc, T, diag::err_incomplete_typeid))
return ExprError();
// C++ [expr.typeid]p3:
// When typeid is applied to an expression other than an glvalue of a
// polymorphic class type [...] [the] expression is an unevaluated
// operand. [...]
if (RecordD->isPolymorphic() && E->isGLValue()) {
// The subexpression is potentially evaluated; switch the context
// and recheck the subexpression.
ExprResult Result = TransformToPotentiallyEvaluated(E);
if (Result.isInvalid()) return ExprError();
E = Result.get();
// We require a vtable to query the type at run time.
MarkVTableUsed(TypeidLoc, RecordD);
WasEvaluated = true;
}
}
ExprResult Result = CheckUnevaluatedOperand(E);
if (Result.isInvalid())
return ExprError();
E = Result.get();
// C++ [expr.typeid]p4:
// [...] If the type of the type-id is a reference to a possibly
// cv-qualified type, the result of the typeid expression refers to a
// std::type_info object representing the cv-unqualified referenced
// type.
Qualifiers Quals;
QualType UnqualT = Context.getUnqualifiedArrayType(T, Quals);
if (!Context.hasSameType(T, UnqualT)) {
T = UnqualT;
E = ImpCastExprToType(E, UnqualT, CK_NoOp, E->getValueKind()).get();
}
}
if (E->getType()->isVariablyModifiedType())
return ExprError(Diag(TypeidLoc, diag::err_variably_modified_typeid)
<< E->getType());
else if (!inTemplateInstantiation() &&
E->HasSideEffects(Context, WasEvaluated)) {
// The expression operand for typeid is in an unevaluated expression
// context, so side effects could result in unintended consequences.
Diag(E->getExprLoc(), WasEvaluated
? diag::warn_side_effects_typeid
: diag::warn_side_effects_unevaluated_context);
}
return new (Context) CXXTypeidExpr(TypeInfoType.withConst(), E,
SourceRange(TypeidLoc, RParenLoc));
}
/// ActOnCXXTypeidOfType - Parse typeid( type-id ) or typeid (expression);
ExprResult
Sema::ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc,
bool isType, void *TyOrExpr, SourceLocation RParenLoc) {
// typeid is not supported in OpenCL.
if (getLangOpts().OpenCLCPlusPlus) {
return ExprError(Diag(OpLoc, diag::err_openclcxx_not_supported)
<< "typeid");
}
// Find the std::type_info type.
if (!getStdNamespace())
return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));
if (!CXXTypeInfoDecl) {
IdentifierInfo *TypeInfoII = &PP.getIdentifierTable().get("type_info");
LookupResult R(*this, TypeInfoII, SourceLocation(), LookupTagName);
LookupQualifiedName(R, getStdNamespace());
CXXTypeInfoDecl = R.getAsSingle<RecordDecl>();
// Microsoft's typeinfo doesn't have type_info in std but in the global
// namespace if _HAS_EXCEPTIONS is defined to 0. See PR13153.
if (!CXXTypeInfoDecl && LangOpts.MSVCCompat) {
LookupQualifiedName(R, Context.getTranslationUnitDecl());
CXXTypeInfoDecl = R.getAsSingle<RecordDecl>();
}
if (!CXXTypeInfoDecl)
return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));
}
if (!getLangOpts().RTTI) {
return ExprError(Diag(OpLoc, diag::err_no_typeid_with_fno_rtti));
}
QualType TypeInfoType = Context.getTypeDeclType(CXXTypeInfoDecl);
if (isType) {
// The operand is a type; handle it as such.
TypeSourceInfo *TInfo = nullptr;
QualType T = GetTypeFromParser(ParsedType::getFromOpaquePtr(TyOrExpr),
&TInfo);
if (T.isNull())
return ExprError();
if (!TInfo)
TInfo = Context.getTrivialTypeSourceInfo(T, OpLoc);
return BuildCXXTypeId(TypeInfoType, OpLoc, TInfo, RParenLoc);
}
// The operand is an expression.
return BuildCXXTypeId(TypeInfoType, OpLoc, (Expr*)TyOrExpr, RParenLoc);
}
/// Grabs __declspec(uuid()) off a type, or returns 0 if we cannot resolve to
/// a single GUID.
static void
getUuidAttrOfType(Sema &SemaRef, QualType QT,
llvm::SmallSetVector<const UuidAttr *, 1> &UuidAttrs) {
// Optionally remove one level of pointer, reference or array indirection.
const Type *Ty = QT.getTypePtr();
if (QT->isPointerType() || QT->isReferenceType())
Ty = QT->getPointeeType().getTypePtr();
else if (QT->isArrayType())
Ty = Ty->getBaseElementTypeUnsafe();
const auto *TD = Ty->getAsTagDecl();
if (!TD)
return;
if (const auto *Uuid = TD->getMostRecentDecl()->getAttr<UuidAttr>()) {
UuidAttrs.insert(Uuid);
return;
}
// __uuidof can grab UUIDs from template arguments.
if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(TD)) {
const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
for (const TemplateArgument &TA : TAL.asArray()) {
const UuidAttr *UuidForTA = nullptr;
if (TA.getKind() == TemplateArgument::Type)
getUuidAttrOfType(SemaRef, TA.getAsType(), UuidAttrs);
else if (TA.getKind() == TemplateArgument::Declaration)
getUuidAttrOfType(SemaRef, TA.getAsDecl()->getType(), UuidAttrs);
if (UuidForTA)
UuidAttrs.insert(UuidForTA);
}
}
}
/// Build a Microsoft __uuidof expression with a type operand.
ExprResult Sema::BuildCXXUuidof(QualType TypeInfoType,
SourceLocation TypeidLoc,
TypeSourceInfo *Operand,
SourceLocation RParenLoc) {
StringRef UuidStr;
if (!Operand->getType()->isDependentType()) {
llvm::SmallSetVector<const UuidAttr *, 1> UuidAttrs;
getUuidAttrOfType(*this, Operand->getType(), UuidAttrs);
if (UuidAttrs.empty())
return ExprError(Diag(TypeidLoc, diag::err_uuidof_without_guid));
if (UuidAttrs.size() > 1)
return ExprError(Diag(TypeidLoc, diag::err_uuidof_with_multiple_guids));
UuidStr = UuidAttrs.back()->getGuid();
}
return new (Context) CXXUuidofExpr(TypeInfoType.withConst(), Operand, UuidStr,
SourceRange(TypeidLoc, RParenLoc));
}
/// Build a Microsoft __uuidof expression with an expression operand.
ExprResult Sema::BuildCXXUuidof(QualType TypeInfoType,
SourceLocation TypeidLoc,
Expr *E,
SourceLocation RParenLoc) {
StringRef UuidStr;
if (!E->getType()->isDependentType()) {
if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull)) {
UuidStr = "00000000-0000-0000-0000-000000000000";
} else {
llvm::SmallSetVector<const UuidAttr *, 1> UuidAttrs;
getUuidAttrOfType(*this, E->getType(), UuidAttrs);
if (UuidAttrs.empty())
return ExprError(Diag(TypeidLoc, diag::err_uuidof_without_guid));
if (UuidAttrs.size() > 1)
return ExprError(Diag(TypeidLoc, diag::err_uuidof_with_multiple_guids));
UuidStr = UuidAttrs.back()->getGuid();
}
}
return new (Context) CXXUuidofExpr(TypeInfoType.withConst(), E, UuidStr,
SourceRange(TypeidLoc, RParenLoc));
}
/// ActOnCXXUuidof - Parse __uuidof( type-id ) or __uuidof (expression);
ExprResult
Sema::ActOnCXXUuidof(SourceLocation OpLoc, SourceLocation LParenLoc,
bool isType, void *TyOrExpr, SourceLocation RParenLoc) {
// If MSVCGuidDecl has not been cached, do the lookup.
if (!MSVCGuidDecl) {
IdentifierInfo *GuidII = &PP.getIdentifierTable().get("_GUID");
LookupResult R(*this, GuidII, SourceLocation(), LookupTagName);
LookupQualifiedName(R, Context.getTranslationUnitDecl());
MSVCGuidDecl = R.getAsSingle<RecordDecl>();
if (!MSVCGuidDecl)
return ExprError(Diag(OpLoc, diag::err_need_header_before_ms_uuidof));
}
QualType GuidType = Context.getTypeDeclType(MSVCGuidDecl);
if (isType) {
// The operand is a type; handle it as such.
TypeSourceInfo *TInfo = nullptr;
QualType T = GetTypeFromParser(ParsedType::getFromOpaquePtr(TyOrExpr),
&TInfo);
if (T.isNull())
return ExprError();
if (!TInfo)
TInfo = Context.getTrivialTypeSourceInfo(T, OpLoc);
return BuildCXXUuidof(GuidType, OpLoc, TInfo, RParenLoc);
}
// The operand is an expression.
return BuildCXXUuidof(GuidType, OpLoc, (Expr*)TyOrExpr, RParenLoc);
}
/// ActOnCXXBoolLiteral - Parse {true,false} literals.
ExprResult
Sema::ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) {
assert((Kind == tok::kw_true || Kind == tok::kw_false) &&
"Unknown C++ Boolean value!");
return new (Context)
CXXBoolLiteralExpr(Kind == tok::kw_true, Context.BoolTy, OpLoc);
}
/// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
ExprResult
Sema::ActOnCXXNullPtrLiteral(SourceLocation Loc) {
return new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
}
/// ActOnCXXThrow - Parse throw expressions.
ExprResult
Sema::ActOnCXXThrow(Scope *S, SourceLocation OpLoc, Expr *Ex) {
bool IsThrownVarInScope = false;
if (Ex) {
// C++0x [class.copymove]p31:
// When certain criteria are met, an implementation is allowed to omit the
// copy/move construction of a class object [...]
//
// - in a throw-expression, when the operand is the name of a
// non-volatile automatic object (other than a function or catch-
// clause parameter) whose scope does not extend beyond the end of the
// innermost enclosing try-block (if there is one), the copy/move
// operation from the operand to the exception object (15.1) can be
// omitted by constructing the automatic object directly into the
// exception object
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Ex->IgnoreParens()))
if (VarDecl *Var = dyn_cast<VarDecl>(DRE->getDecl())) {
if (Var->hasLocalStorage() && !Var->getType().isVolatileQualified()) {
for( ; S; S = S->getParent()) {
if (S->isDeclScope(Var)) {
IsThrownVarInScope = true;
break;
}
if (S->getFlags() &
(Scope::FnScope | Scope::ClassScope | Scope::BlockScope |
Scope::FunctionPrototypeScope | Scope::ObjCMethodScope |
Scope::TryScope))
break;
}
}
}
}
return BuildCXXThrow(OpLoc, Ex, IsThrownVarInScope);
}
ExprResult Sema::BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
bool IsThrownVarInScope) {
// Don't report an error if 'throw' is used in system headers.
if (!getLangOpts().CXXExceptions &&
!getSourceManager().isInSystemHeader(OpLoc) && !getLangOpts().CUDA) {
// Delay error emission for the OpenMP device code.
targetDiag(OpLoc, diag::err_exceptions_disabled) << "throw";
}
// Exceptions aren't allowed in CUDA device code.
if (getLangOpts().CUDA)
CUDADiagIfDeviceCode(OpLoc, diag::err_cuda_device_exceptions)
<< "throw" << CurrentCUDATarget();
if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
Diag(OpLoc, diag::err_omp_simd_region_cannot_use_stmt) << "throw";
if (Ex && !Ex->isTypeDependent()) {
QualType ExceptionObjectTy = Context.getExceptionObjectType(Ex->getType());
if (CheckCXXThrowOperand(OpLoc, ExceptionObjectTy, Ex))
return ExprError();
// Initialize the exception result. This implicitly weeds out
// abstract types or types with inaccessible copy constructors.
// C++0x [class.copymove]p31:
// When certain criteria are met, an implementation is allowed to omit the
// copy/move construction of a class object [...]
//
// - in a throw-expression, when the operand is the name of a
// non-volatile automatic object (other than a function or
// catch-clause
// parameter) whose scope does not extend beyond the end of the
// innermost enclosing try-block (if there is one), the copy/move
// operation from the operand to the exception object (15.1) can be
// omitted by constructing the automatic object directly into the
// exception object
const VarDecl *NRVOVariable = nullptr;
if (IsThrownVarInScope)
NRVOVariable = getCopyElisionCandidate(QualType(), Ex, CES_Strict);
InitializedEntity Entity = InitializedEntity::InitializeException(
OpLoc, ExceptionObjectTy,
/*NRVO=*/NRVOVariable != nullptr);
ExprResult Res = PerformMoveOrCopyInitialization(
Entity, NRVOVariable, QualType(), Ex, IsThrownVarInScope);
if (Res.isInvalid())
return ExprError();
Ex = Res.get();
}
return new (Context)
CXXThrowExpr(Ex, Context.VoidTy, OpLoc, IsThrownVarInScope);
}
static void
collectPublicBases(CXXRecordDecl *RD,
llvm::DenseMap<CXXRecordDecl *, unsigned> &SubobjectsSeen,
llvm::SmallPtrSetImpl<CXXRecordDecl *> &VBases,
llvm::SetVector<CXXRecordDecl *> &PublicSubobjectsSeen,
bool ParentIsPublic) {
for (const CXXBaseSpecifier &BS : RD->bases()) {
CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
bool NewSubobject;
// Virtual bases constitute the same subobject. Non-virtual bases are
// always distinct subobjects.
if (BS.isVirtual())
NewSubobject = VBases.insert(BaseDecl).second;
else
NewSubobject = true;
if (NewSubobject)
++SubobjectsSeen[BaseDecl];
// Only add subobjects which have public access throughout the entire chain.
bool PublicPath = ParentIsPublic && BS.getAccessSpecifier() == AS_public;
if (PublicPath)
PublicSubobjectsSeen.insert(BaseDecl);
// Recurse on to each base subobject.
collectPublicBases(BaseDecl, SubobjectsSeen, VBases, PublicSubobjectsSeen,
PublicPath);
}
}
static void getUnambiguousPublicSubobjects(
CXXRecordDecl *RD, llvm::SmallVectorImpl<CXXRecordDecl *> &Objects) {
llvm::DenseMap<CXXRecordDecl *, unsigned> SubobjectsSeen;
llvm::SmallSet<CXXRecordDecl *, 2> VBases;
llvm::SetVector<CXXRecordDecl *> PublicSubobjectsSeen;
SubobjectsSeen[RD] = 1;
PublicSubobjectsSeen.insert(RD);
collectPublicBases(RD, SubobjectsSeen, VBases, PublicSubobjectsSeen,
/*ParentIsPublic=*/true);
for (CXXRecordDecl *PublicSubobject : PublicSubobjectsSeen) {
// Skip ambiguous objects.
if (SubobjectsSeen[PublicSubobject] > 1)
continue;
Objects.push_back(PublicSubobject);
}
}
/// CheckCXXThrowOperand - Validate the operand of a throw.
bool Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc,
QualType ExceptionObjectTy, Expr *E) {
// If the type of the exception would be an incomplete type or a pointer
// to an incomplete type other than (cv) void the program is ill-formed.
QualType Ty = ExceptionObjectTy;
bool isPointer = false;
if (const PointerType* Ptr = Ty->getAs<PointerType>()) {
Ty = Ptr->getPointeeType();
isPointer = true;
}
if (!isPointer || !Ty->isVoidType()) {
if (RequireCompleteType(ThrowLoc, Ty,
isPointer ? diag::err_throw_incomplete_ptr
: diag::err_throw_incomplete,
E->getSourceRange()))
return true;
if (RequireNonAbstractType(ThrowLoc, ExceptionObjectTy,
diag::err_throw_abstract_type, E))
return true;
}
// If the exception has class type, we need additional handling.
CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
if (!RD)
return false;
// If we are throwing a polymorphic class type or pointer thereof,
// exception handling will make use of the vtable.
MarkVTableUsed(ThrowLoc, RD);
// If a pointer is thrown, the referenced object will not be destroyed.
if (isPointer)
return false;
// If the class has a destructor, we must be able to call it.
if (!RD->hasIrrelevantDestructor()) {
if (CXXDestructorDecl *Destructor = LookupDestructor(RD)) {
MarkFunctionReferenced(E->getExprLoc(), Destructor);
CheckDestructorAccess(E->getExprLoc(), Destructor,
PDiag(diag::err_access_dtor_exception) << Ty);
if (DiagnoseUseOfDecl(Destructor, E->getExprLoc()))
return true;
}
}
// The MSVC ABI creates a list of all types which can catch the exception
// object. This list also references the appropriate copy constructor to call
// if the object is caught by value and has a non-trivial copy constructor.
if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
// We are only interested in the public, unambiguous bases contained within
// the exception object. Bases which are ambiguous or otherwise
// inaccessible are not catchable types.
llvm::SmallVector<CXXRecordDecl *, 2> UnambiguousPublicSubobjects;
getUnambiguousPublicSubobjects(RD, UnambiguousPublicSubobjects);
for (CXXRecordDecl *Subobject : UnambiguousPublicSubobjects) {
// Attempt to lookup the copy constructor. Various pieces of machinery
// will spring into action, like template instantiation, which means this
// cannot be a simple walk of the class's decls. Instead, we must perform
// lookup and overload resolution.
CXXConstructorDecl *CD = LookupCopyingConstructor(Subobject, 0);
if (!CD || CD->isDeleted())
continue;
// Mark the constructor referenced as it is used by this throw expression.
MarkFunctionReferenced(E->getExprLoc(), CD);
// Skip this copy constructor if it is trivial, we don't need to record it
// in the catchable type data.
if (CD->isTrivial())
continue;
// The copy constructor is non-trivial, create a mapping from this class
// type to this constructor.
// N.B. The selection of copy constructor is not sensitive to this
// particular throw-site. Lookup will be performed at the catch-site to
// ensure that the copy constructor is, in fact, accessible (via
// friendship or any other means).
Context.addCopyConstructorForExceptionObject(Subobject, CD);
// We don't keep the instantiated default argument expressions around so
// we must rebuild them here.
for (unsigned I = 1, E = CD->getNumParams(); I != E; ++I) {
if (CheckCXXDefaultArgExpr(ThrowLoc, CD, CD->getParamDecl(I)))
return true;
}
}
}
// Under the Itanium C++ ABI, memory for the exception object is allocated by
// the runtime with no ability for the compiler to request additional
// alignment. Warn if the exception type requires alignment beyond the minimum
// guaranteed by the target C++ runtime.
if (Context.getTargetInfo().getCXXABI().isItaniumFamily()) {
CharUnits TypeAlign = Context.getTypeAlignInChars(Ty);
CharUnits ExnObjAlign = Context.getExnObjectAlignment();
if (ExnObjAlign < TypeAlign) {
Diag(ThrowLoc, diag::warn_throw_underaligned_obj);
Diag(ThrowLoc, diag::note_throw_underaligned_obj)
<< Ty << (unsigned)TypeAlign.getQuantity()
<< (unsigned)ExnObjAlign.getQuantity();
}
}
return false;
}
static QualType adjustCVQualifiersForCXXThisWithinLambda(
ArrayRef<FunctionScopeInfo *> FunctionScopes, QualType ThisTy,
DeclContext *CurSemaContext, ASTContext &ASTCtx) {
QualType ClassType = ThisTy->getPointeeType();
LambdaScopeInfo *CurLSI = nullptr;
DeclContext *CurDC = CurSemaContext;
// Iterate through the stack of lambdas starting from the innermost lambda to
// the outermost lambda, checking if '*this' is ever captured by copy - since
// that could change the cv-qualifiers of the '*this' object.
// The object referred to by '*this' starts out with the cv-qualifiers of its
// member function. We then start with the innermost lambda and iterate
// outward checking to see if any lambda performs a by-copy capture of '*this'
// - and if so, any nested lambda must respect the 'constness' of that
// capturing lamdbda's call operator.
//
// Since the FunctionScopeInfo stack is representative of the lexical
// nesting of the lambda expressions during initial parsing (and is the best
// place for querying information about captures about lambdas that are
// partially processed) and perhaps during instantiation of function templates
// that contain lambda expressions that need to be transformed BUT not
// necessarily during instantiation of a nested generic lambda's function call
// operator (which might even be instantiated at the end of the TU) - at which
// time the DeclContext tree is mature enough to query capture information
// reliably - we use a two pronged approach to walk through all the lexically
// enclosing lambda expressions:
//
// 1) Climb down the FunctionScopeInfo stack as long as each item represents
// a Lambda (i.e. LambdaScopeInfo) AND each LSI's 'closure-type' is lexically