ExprClassification.cpp [plain text]
#include "llvm/Support/ErrorHandling.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclTemplate.h"
using namespace clang;
typedef Expr::Classification Cl;
static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E);
static Cl::Kinds ClassifyDecl(ASTContext &Ctx, const Decl *D);
static Cl::Kinds ClassifyUnnamed(ASTContext &Ctx, QualType T);
static Cl::Kinds ClassifyMemberExpr(ASTContext &Ctx, const MemberExpr *E);
static Cl::Kinds ClassifyBinaryOp(ASTContext &Ctx, const BinaryOperator *E);
static Cl::Kinds ClassifyConditional(ASTContext &Ctx,
const Expr *trueExpr,
const Expr *falseExpr);
static Cl::ModifiableType IsModifiable(ASTContext &Ctx, const Expr *E,
Cl::Kinds Kind, SourceLocation &Loc);
static Cl::Kinds ClassifyExprValueKind(const LangOptions &Lang,
const Expr *E,
ExprValueKind Kind) {
switch (Kind) {
case VK_RValue:
return Lang.CPlusPlus && E->getType()->isRecordType() ?
Cl::CL_ClassTemporary : Cl::CL_PRValue;
case VK_LValue:
return Cl::CL_LValue;
case VK_XValue:
return Cl::CL_XValue;
}
llvm_unreachable("Invalid value category of implicit cast.");
}
Cl Expr::ClassifyImpl(ASTContext &Ctx, SourceLocation *Loc) const {
assert(!TR->isReferenceType() && "Expressions can't have reference type.");
Cl::Kinds kind = ClassifyInternal(Ctx, this);
if (!Ctx.getLangOpts().CPlusPlus) {
if (TR->isFunctionType() || TR == Ctx.OverloadTy)
kind = Cl::CL_Function;
else if (TR->isVoidType() && !TR.hasQualifiers())
kind = (kind == Cl::CL_LValue ? Cl::CL_AddressableVoid : Cl::CL_Void);
}
switch (kind) {
case Cl::CL_LValue: assert(getValueKind() == VK_LValue); break;
case Cl::CL_XValue: assert(getValueKind() == VK_XValue); break;
case Cl::CL_Function:
case Cl::CL_Void:
case Cl::CL_AddressableVoid:
case Cl::CL_DuplicateVectorComponents:
case Cl::CL_MemberFunction:
case Cl::CL_SubObjCPropertySetting:
case Cl::CL_ClassTemporary:
case Cl::CL_ArrayTemporary:
case Cl::CL_ObjCMessageRValue:
case Cl::CL_PRValue: assert(getValueKind() == VK_RValue); break;
}
Cl::ModifiableType modifiable = Cl::CM_Untested;
if (Loc)
modifiable = IsModifiable(Ctx, this, kind, *Loc);
return Classification(kind, modifiable);
}
static Cl::Kinds ClassifyTemporary(QualType T) {
if (T->isRecordType())
return Cl::CL_ClassTemporary;
if (T->isArrayType())
return Cl::CL_ArrayTemporary;
return Cl::CL_PRValue;
}
static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) {
const LangOptions &Lang = Ctx.getLangOpts();
switch (E->getStmtClass()) {
case Stmt::NoStmtClass:
#define ABSTRACT_STMT(Kind)
#define STMT(Kind, Base) case Expr::Kind##Class:
#define EXPR(Kind, Base)
#include "clang/AST/StmtNodes.inc"
llvm_unreachable("cannot classify a statement");
case Expr::ObjCIsaExprClass:
case Expr::StringLiteralClass:
case Expr::ObjCEncodeExprClass:
case Expr::PredefinedExprClass:
case Expr::ObjCSubscriptRefExprClass:
case Expr::ObjCPropertyRefExprClass:
case Expr::CXXTypeidExprClass:
case Expr::UnresolvedLookupExprClass:
case Expr::UnresolvedMemberExprClass:
case Expr::CXXDependentScopeMemberExprClass:
case Expr::DependentScopeDeclRefExprClass:
case Expr::ObjCIvarRefExprClass:
case Expr::FunctionParmPackExprClass:
return Cl::CL_LValue;
case Expr::CompoundLiteralExprClass:
return Ctx.getLangOpts().CPlusPlus ? ClassifyTemporary(E->getType())
: Cl::CL_LValue;
case Expr::CXXBoolLiteralExprClass:
case Expr::CXXPseudoDestructorExprClass:
case Expr::UnaryExprOrTypeTraitExprClass:
case Expr::CXXNewExprClass:
case Expr::CXXThisExprClass:
case Expr::CXXNullPtrLiteralExprClass:
case Expr::ImaginaryLiteralClass:
case Expr::GNUNullExprClass:
case Expr::OffsetOfExprClass:
case Expr::CXXThrowExprClass:
case Expr::ShuffleVectorExprClass:
case Expr::IntegerLiteralClass:
case Expr::CharacterLiteralClass:
case Expr::AddrLabelExprClass:
case Expr::CXXDeleteExprClass:
case Expr::ImplicitValueInitExprClass:
case Expr::BlockExprClass:
case Expr::FloatingLiteralClass:
case Expr::CXXNoexceptExprClass:
case Expr::CXXScalarValueInitExprClass:
case Expr::UnaryTypeTraitExprClass:
case Expr::BinaryTypeTraitExprClass:
case Expr::TypeTraitExprClass:
case Expr::ArrayTypeTraitExprClass:
case Expr::ExpressionTraitExprClass:
case Expr::ObjCSelectorExprClass:
case Expr::ObjCProtocolExprClass:
case Expr::ObjCStringLiteralClass:
case Expr::ObjCBoxedExprClass:
case Expr::ObjCArrayLiteralClass:
case Expr::ObjCDictionaryLiteralClass:
case Expr::ObjCBoolLiteralExprClass:
case Expr::ParenListExprClass:
case Expr::SizeOfPackExprClass:
case Expr::SubstNonTypeTemplateParmPackExprClass:
case Expr::AsTypeExprClass:
case Expr::ObjCIndirectCopyRestoreExprClass:
case Expr::AtomicExprClass:
return Cl::CL_PRValue;
case Expr::SubstNonTypeTemplateParmExprClass:
return ClassifyInternal(Ctx,
cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement());
case Expr::ArraySubscriptExprClass:
if (cast<ArraySubscriptExpr>(E)->getBase()->getType()->isVectorType())
return ClassifyInternal(Ctx, cast<ArraySubscriptExpr>(E)->getBase());
return Cl::CL_LValue;
case Expr::DeclRefExprClass:
if (E->getType() == Ctx.UnknownAnyTy)
return isa<FunctionDecl>(cast<DeclRefExpr>(E)->getDecl())
? Cl::CL_PRValue : Cl::CL_LValue;
return ClassifyDecl(Ctx, cast<DeclRefExpr>(E)->getDecl());
case Expr::MemberExprClass:
return ClassifyMemberExpr(Ctx, cast<MemberExpr>(E));
case Expr::UnaryOperatorClass:
switch (cast<UnaryOperator>(E)->getOpcode()) {
case UO_Deref:
return Cl::CL_LValue;
case UO_Extension:
return ClassifyInternal(Ctx, cast<UnaryOperator>(E)->getSubExpr());
case UO_Real:
case UO_Imag: {
const Expr *Op = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens();
Cl::Kinds K = ClassifyInternal(Ctx, Op);
if (K != Cl::CL_LValue) return K;
if (isa<ObjCPropertyRefExpr>(Op))
return Cl::CL_SubObjCPropertySetting;
return Cl::CL_LValue;
}
case UO_PreInc:
case UO_PreDec:
return Lang.CPlusPlus ? Cl::CL_LValue : Cl::CL_PRValue;
default:
return Cl::CL_PRValue;
}
case Expr::OpaqueValueExprClass:
return ClassifyExprValueKind(Lang, E, E->getValueKind());
case Expr::PseudoObjectExprClass:
return ClassifyExprValueKind(Lang, E,
cast<PseudoObjectExpr>(E)->getValueKind());
case Expr::ImplicitCastExprClass:
return ClassifyExprValueKind(Lang, E, E->getValueKind());
case Expr::ParenExprClass:
return ClassifyInternal(Ctx, cast<ParenExpr>(E)->getSubExpr());
case Expr::GenericSelectionExprClass:
if (cast<GenericSelectionExpr>(E)->isResultDependent())
return Cl::CL_PRValue;
return ClassifyInternal(Ctx,cast<GenericSelectionExpr>(E)->getResultExpr());
case Expr::BinaryOperatorClass:
case Expr::CompoundAssignOperatorClass:
if (Lang.CPlusPlus)
return ClassifyBinaryOp(Ctx, cast<BinaryOperator>(E));
return Cl::CL_PRValue;
case Expr::CallExprClass:
case Expr::CXXOperatorCallExprClass:
case Expr::CXXMemberCallExprClass:
case Expr::UserDefinedLiteralClass:
case Expr::CUDAKernelCallExprClass:
return ClassifyUnnamed(Ctx, cast<CallExpr>(E)->getCallReturnType());
case Expr::ChooseExprClass:
return ClassifyInternal(Ctx, cast<ChooseExpr>(E)->getChosenSubExpr(Ctx));
case Expr::ExtVectorElementExprClass:
return cast<ExtVectorElementExpr>(E)->containsDuplicateElements() ?
Cl::CL_DuplicateVectorComponents : Cl::CL_LValue;
case Expr::CXXDefaultArgExprClass:
return ClassifyInternal(Ctx, cast<CXXDefaultArgExpr>(E)->getExpr());
case Expr::CXXBindTemporaryExprClass:
return ClassifyInternal(Ctx, cast<CXXBindTemporaryExpr>(E)->getSubExpr());
case Expr::ExprWithCleanupsClass:
return ClassifyInternal(Ctx, cast<ExprWithCleanups>(E)->getSubExpr());
case Expr::CStyleCastExprClass:
case Expr::CXXFunctionalCastExprClass:
case Expr::CXXStaticCastExprClass:
case Expr::CXXDynamicCastExprClass:
case Expr::CXXReinterpretCastExprClass:
case Expr::CXXConstCastExprClass:
case Expr::ObjCBridgedCastExprClass:
if (!Lang.CPlusPlus) return Cl::CL_PRValue;
return ClassifyUnnamed(Ctx, cast<ExplicitCastExpr>(E)->getTypeAsWritten());
case Expr::CXXUnresolvedConstructExprClass:
return ClassifyUnnamed(Ctx,
cast<CXXUnresolvedConstructExpr>(E)->getTypeAsWritten());
case Expr::BinaryConditionalOperatorClass: {
if (!Lang.CPlusPlus) return Cl::CL_PRValue;
const BinaryConditionalOperator *co = cast<BinaryConditionalOperator>(E);
return ClassifyConditional(Ctx, co->getTrueExpr(), co->getFalseExpr());
}
case Expr::ConditionalOperatorClass: {
if (!Lang.CPlusPlus) return Cl::CL_PRValue;
const ConditionalOperator *co = cast<ConditionalOperator>(E);
return ClassifyConditional(Ctx, co->getTrueExpr(), co->getFalseExpr());
}
case Expr::ObjCMessageExprClass:
if (const ObjCMethodDecl *Method =
cast<ObjCMessageExpr>(E)->getMethodDecl()) {
Cl::Kinds kind = ClassifyUnnamed(Ctx, Method->getResultType());
return (kind == Cl::CL_PRValue) ? Cl::CL_ObjCMessageRValue : kind;
}
return Cl::CL_PRValue;
case Expr::CXXConstructExprClass:
case Expr::CXXTemporaryObjectExprClass:
case Expr::LambdaExprClass:
return Cl::CL_ClassTemporary;
case Expr::VAArgExprClass:
return ClassifyUnnamed(Ctx, E->getType());
case Expr::DesignatedInitExprClass:
return ClassifyInternal(Ctx, cast<DesignatedInitExpr>(E)->getInit());
case Expr::StmtExprClass: {
const CompoundStmt *S = cast<StmtExpr>(E)->getSubStmt();
if (const Expr *LastExpr = dyn_cast_or_null<Expr>(S->body_back()))
return ClassifyUnnamed(Ctx, LastExpr->getType());
return Cl::CL_PRValue;
}
case Expr::CXXUuidofExprClass:
return Cl::CL_LValue;
case Expr::PackExpansionExprClass:
return ClassifyInternal(Ctx, cast<PackExpansionExpr>(E)->getPattern());
case Expr::MaterializeTemporaryExprClass:
return cast<MaterializeTemporaryExpr>(E)->isBoundToLvalueReference()
? Cl::CL_LValue
: Cl::CL_XValue;
case Expr::InitListExprClass:
if (E->isRValue())
return ClassifyExprValueKind(Lang, E, E->getValueKind());
assert(cast<InitListExpr>(E)->getNumInits() == 1 &&
"Only 1-element init lists can be glvalues.");
return ClassifyInternal(Ctx, cast<InitListExpr>(E)->getInit(0));
}
llvm_unreachable("unhandled expression kind in classification");
}
static Cl::Kinds ClassifyDecl(ASTContext &Ctx, const Decl *D) {
if (isa<CXXMethodDecl>(D) && cast<CXXMethodDecl>(D)->isInstance())
return Cl::CL_MemberFunction;
bool islvalue;
if (const NonTypeTemplateParmDecl *NTTParm =
dyn_cast<NonTypeTemplateParmDecl>(D))
islvalue = NTTParm->getType()->isReferenceType();
else
islvalue = isa<VarDecl>(D) || isa<FieldDecl>(D) ||
isa<IndirectFieldDecl>(D) ||
(Ctx.getLangOpts().CPlusPlus &&
(isa<FunctionDecl>(D) || isa<FunctionTemplateDecl>(D)));
return islvalue ? Cl::CL_LValue : Cl::CL_PRValue;
}
static Cl::Kinds ClassifyUnnamed(ASTContext &Ctx, QualType T) {
if (!Ctx.getLangOpts().CPlusPlus) return Cl::CL_PRValue;
if (T->isLValueReferenceType())
return Cl::CL_LValue;
const RValueReferenceType *RV = T->getAs<RValueReferenceType>();
if (!RV) return ClassifyTemporary(T);
return RV->getPointeeType()->isFunctionType() ? Cl::CL_LValue : Cl::CL_XValue;
}
static Cl::Kinds ClassifyMemberExpr(ASTContext &Ctx, const MemberExpr *E) {
if (E->getType() == Ctx.UnknownAnyTy)
return (isa<FunctionDecl>(E->getMemberDecl())
? Cl::CL_PRValue : Cl::CL_LValue);
if (!Ctx.getLangOpts().CPlusPlus) {
if (E->isArrow())
return Cl::CL_LValue;
Expr *Base = E->getBase()->IgnoreParens();
if (isa<ObjCPropertyRefExpr>(Base))
return Cl::CL_SubObjCPropertySetting;
return ClassifyInternal(Ctx, Base);
}
NamedDecl *Member = E->getMemberDecl();
if (ValueDecl *Value = dyn_cast<ValueDecl>(Member))
if (Value->getType()->isReferenceType())
return Cl::CL_LValue;
if (isa<VarDecl>(Member) && Member->getDeclContext()->isRecord())
return Cl::CL_LValue;
if (isa<FieldDecl>(Member)) {
if (E->isArrow())
return Cl::CL_LValue;
Expr *Base = E->getBase()->IgnoreParenImpCasts();
if (isa<ObjCPropertyRefExpr>(Base))
return Cl::CL_SubObjCPropertySetting;
return ClassifyInternal(Ctx, E->getBase());
}
if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Member))
return Method->isStatic() ? Cl::CL_LValue : Cl::CL_MemberFunction;
return Cl::CL_PRValue;
}
static Cl::Kinds ClassifyBinaryOp(ASTContext &Ctx, const BinaryOperator *E) {
assert(Ctx.getLangOpts().CPlusPlus &&
"This is only relevant for C++.");
if (E->isAssignmentOp())
return (E->getLHS()->getObjectKind() == OK_ObjCProperty
? Cl::CL_PRValue : Cl::CL_LValue);
if (E->getOpcode() == BO_Comma)
return ClassifyInternal(Ctx, E->getRHS());
if (E->getOpcode() == BO_PtrMemD)
return (E->getType()->isFunctionType() ||
E->hasPlaceholderType(BuiltinType::BoundMember))
? Cl::CL_MemberFunction
: ClassifyInternal(Ctx, E->getLHS());
if (E->getOpcode() == BO_PtrMemI)
return (E->getType()->isFunctionType() ||
E->hasPlaceholderType(BuiltinType::BoundMember))
? Cl::CL_MemberFunction
: Cl::CL_LValue;
return Cl::CL_PRValue;
}
static Cl::Kinds ClassifyConditional(ASTContext &Ctx, const Expr *True,
const Expr *False) {
assert(Ctx.getLangOpts().CPlusPlus &&
"This is only relevant for C++.");
if (True->getType()->isVoidType() || False->getType()->isVoidType())
return Cl::CL_PRValue;
Cl::Kinds LCl = ClassifyInternal(Ctx, True),
RCl = ClassifyInternal(Ctx, False);
return LCl == RCl ? LCl : Cl::CL_PRValue;
}
static Cl::ModifiableType IsModifiable(ASTContext &Ctx, const Expr *E,
Cl::Kinds Kind, SourceLocation &Loc) {
if (Kind == Cl::CL_PRValue) {
if (const ExplicitCastExpr *CE =
dyn_cast<ExplicitCastExpr>(E->IgnoreParens())) {
if (CE->getSubExpr()->IgnoreParenImpCasts()->isLValue()) {
Loc = CE->getExprLoc();
return Cl::CM_LValueCast;
}
}
}
if (Kind != Cl::CL_LValue)
return Cl::CM_RValue;
if (Ctx.getLangOpts().CPlusPlus && E->getType()->isFunctionType())
return Cl::CM_Function;
if (const ObjCPropertyRefExpr *Expr = dyn_cast<ObjCPropertyRefExpr>(E)) {
if (Expr->isImplicitProperty() && Expr->getImplicitPropertySetter() == 0)
return Cl::CM_NoSetterProperty;
}
CanQualType CT = Ctx.getCanonicalType(E->getType());
if (CT.isConstQualified())
return Cl::CM_ConstQualified;
if (CT->isArrayType())
return Cl::CM_ArrayType;
if (CT->isIncompleteType())
return Cl::CM_IncompleteType;
if (const RecordType *R = CT->getAs<RecordType>()) {
assert((E->getObjectKind() == OK_ObjCProperty ||
!Ctx.getLangOpts().CPlusPlus) &&
"C++ struct assignment should be resolved by the "
"copy assignment operator.");
if (R->hasConstFields())
return Cl::CM_ConstQualified;
}
return Cl::CM_Modifiable;
}
Expr::LValueClassification Expr::ClassifyLValue(ASTContext &Ctx) const {
Classification VC = Classify(Ctx);
switch (VC.getKind()) {
case Cl::CL_LValue: return LV_Valid;
case Cl::CL_XValue: return LV_InvalidExpression;
case Cl::CL_Function: return LV_NotObjectType;
case Cl::CL_Void: return LV_InvalidExpression;
case Cl::CL_AddressableVoid: return LV_IncompleteVoidType;
case Cl::CL_DuplicateVectorComponents: return LV_DuplicateVectorComponents;
case Cl::CL_MemberFunction: return LV_MemberFunction;
case Cl::CL_SubObjCPropertySetting: return LV_SubObjCPropertySetting;
case Cl::CL_ClassTemporary: return LV_ClassTemporary;
case Cl::CL_ArrayTemporary: return LV_ArrayTemporary;
case Cl::CL_ObjCMessageRValue: return LV_InvalidMessageExpression;
case Cl::CL_PRValue: return LV_InvalidExpression;
}
llvm_unreachable("Unhandled kind");
}
Expr::isModifiableLvalueResult
Expr::isModifiableLvalue(ASTContext &Ctx, SourceLocation *Loc) const {
SourceLocation dummy;
Classification VC = ClassifyModifiable(Ctx, Loc ? *Loc : dummy);
switch (VC.getKind()) {
case Cl::CL_LValue: break;
case Cl::CL_XValue: return MLV_InvalidExpression;
case Cl::CL_Function: return MLV_NotObjectType;
case Cl::CL_Void: return MLV_InvalidExpression;
case Cl::CL_AddressableVoid: return MLV_IncompleteVoidType;
case Cl::CL_DuplicateVectorComponents: return MLV_DuplicateVectorComponents;
case Cl::CL_MemberFunction: return MLV_MemberFunction;
case Cl::CL_SubObjCPropertySetting: return MLV_SubObjCPropertySetting;
case Cl::CL_ClassTemporary: return MLV_ClassTemporary;
case Cl::CL_ArrayTemporary: return MLV_ArrayTemporary;
case Cl::CL_ObjCMessageRValue: return MLV_InvalidMessageExpression;
case Cl::CL_PRValue:
return VC.getModifiable() == Cl::CM_LValueCast ?
MLV_LValueCast : MLV_InvalidExpression;
}
assert(VC.getKind() == Cl::CL_LValue && "Unhandled kind");
switch (VC.getModifiable()) {
case Cl::CM_Untested: llvm_unreachable("Did not test modifiability");
case Cl::CM_Modifiable: return MLV_Valid;
case Cl::CM_RValue: llvm_unreachable("CM_RValue and CL_LValue don't match");
case Cl::CM_Function: return MLV_NotObjectType;
case Cl::CM_LValueCast:
llvm_unreachable("CM_LValueCast and CL_LValue don't match");
case Cl::CM_NoSetterProperty: return MLV_NoSetterProperty;
case Cl::CM_ConstQualified: return MLV_ConstQualified;
case Cl::CM_ArrayType: return MLV_ArrayType;
case Cl::CM_IncompleteType: return MLV_IncompleteType;
}
llvm_unreachable("Unhandled modifiable type");
}