//===- Initialization.h - Semantic Analysis for Initializers ----*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file provides supporting data types for initialization of objects.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_SEMA_INITIALIZATION_H
#define LLVM_CLANG_SEMA_INITIALIZATION_H
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclAccessPair.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Type.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Sema/Overload.h"
#include "clang/Sema/Ownership.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/Casting.h"
#include <cassert>
#include <cstdint>
#include <string>
namespace clang {
class CXXBaseSpecifier;
class CXXConstructorDecl;
class ObjCMethodDecl;
class Sema;
/// Describes an entity that is being initialized.
class alignas(8) InitializedEntity {
public:
/// Specifies the kind of entity being initialized.
enum EntityKind {
/// The entity being initialized is a variable.
EK_Variable,
/// The entity being initialized is a function parameter.
EK_Parameter,
/// The entity being initialized is a non-type template parameter.
EK_TemplateParameter,
/// The entity being initialized is the result of a function call.
EK_Result,
/// The entity being initialized is the result of a statement expression.
EK_StmtExprResult,
/// The entity being initialized is an exception object that
/// is being thrown.
EK_Exception,
/// The entity being initialized is a non-static data member
/// subobject.
EK_Member,
/// The entity being initialized is an element of an array.
EK_ArrayElement,
/// The entity being initialized is an object (or array of
/// objects) allocated via new.
EK_New,
/// The entity being initialized is a temporary object.
EK_Temporary,
/// The entity being initialized is a base member subobject.
EK_Base,
/// The initialization is being done by a delegating constructor.
EK_Delegating,
/// The entity being initialized is an element of a vector.
/// or vector.
EK_VectorElement,
/// The entity being initialized is a field of block descriptor for
/// the copied-in c++ object.
EK_BlockElement,
/// The entity being initialized is a field of block descriptor for the
/// copied-in lambda object that's used in the lambda to block conversion.
EK_LambdaToBlockConversionBlockElement,
/// The entity being initialized is the real or imaginary part of a
/// complex number.
EK_ComplexElement,
/// The entity being initialized is the field that captures a
/// variable in a lambda.
EK_LambdaCapture,
/// The entity being initialized is the initializer for a compound
/// literal.
EK_CompoundLiteralInit,
/// The entity being implicitly initialized back to the formal
/// result type.
EK_RelatedResult,
/// The entity being initialized is a function parameter; function
/// is member of group of audited CF APIs.
EK_Parameter_CF_Audited,
/// The entity being initialized is a structured binding of a
/// decomposition declaration.
EK_Binding,
/// The entity being initialized is a non-static data member subobject of an
/// object initialized via parenthesized aggregate initialization.
EK_ParenAggInitMember,
// Note: err_init_conversion_failed in DiagnosticSemaKinds.td uses this
// enum as an index for its first %select. When modifying this list,
// that diagnostic text needs to be updated as well.
};
private:
/// The kind of entity being initialized.
EntityKind Kind;
/// If non-NULL, the parent entity in which this
/// initialization occurs.
const InitializedEntity *Parent = nullptr;
/// The type of the object or reference being initialized.
QualType Type;
/// The mangling number for the next reference temporary to be created.
mutable unsigned ManglingNumber = 0;
struct LN {
/// When Kind == EK_Result, EK_Exception, EK_New, the
/// location of the 'return', 'throw', or 'new' keyword,
/// respectively. When Kind == EK_Temporary, the location where
/// the temporary is being created.
SourceLocation Location;
/// Whether the entity being initialized may end up using the
/// named return value optimization (NRVO).
bool NRVO;
};
struct VD {
/// The VarDecl, FieldDecl, or BindingDecl being initialized.
ValueDecl *VariableOrMember;
/// When Kind == EK_Member, whether this is an implicit member
/// initialization in a copy or move constructor. These can perform array
/// copies.
bool IsImplicitFieldInit;
/// When Kind == EK_Member, whether this is the initial initialization
/// check for a default member initializer.
bool IsDefaultMemberInit;
};
struct C {
/// The name of the variable being captured by an EK_LambdaCapture.
IdentifierInfo *VarID;
/// The source location at which the capture occurs.
SourceLocation Location;
};
union {
/// When Kind == EK_Variable, EK_Member, EK_Binding, or
/// EK_TemplateParameter, the variable, binding, or template parameter.
VD Variable;
/// When Kind == EK_RelatedResult, the ObjectiveC method where
/// result type was implicitly changed to accommodate ARC semantics.
ObjCMethodDecl *MethodDecl;
/// When Kind == EK_Parameter, the ParmVarDecl, with the
/// integer indicating whether the parameter is "consumed".
llvm::PointerIntPair<ParmVarDecl *, 1> Parameter;
/// When Kind == EK_Temporary or EK_CompoundLiteralInit, the type
/// source information for the temporary.
TypeSourceInfo *TypeInfo;
struct LN LocAndNRVO;
/// When Kind == EK_Base, the base specifier that provides the
/// base class. The integer specifies whether the base is an inherited
/// virtual base.
llvm::PointerIntPair<const CXXBaseSpecifier *, 1> Base;
/// When Kind == EK_ArrayElement, EK_VectorElement, or
/// EK_ComplexElement, the index of the array or vector element being
/// initialized.
unsigned Index;
struct C Capture;
};
InitializedEntity() {};
/// Create the initialization entity for a variable.
InitializedEntity(VarDecl *Var, EntityKind EK = EK_Variable)
: Kind(EK), Type(Var->getType()), Variable{Var, false, false} {}
/// Create the initialization entity for the result of a
/// function, throwing an object, performing an explicit cast, or
/// initializing a parameter for which there is no declaration.
InitializedEntity(EntityKind Kind, SourceLocation Loc, QualType Type,
bool NRVO = false)
: Kind(Kind), Type(Type) {
new (&LocAndNRVO) LN;
LocAndNRVO.Location = Loc;
LocAndNRVO.NRVO = NRVO;
}
/// Create the initialization entity for a member subobject.
InitializedEntity(FieldDecl *Member, const InitializedEntity *Parent,
bool Implicit, bool DefaultMemberInit,
bool IsParenAggInit = false)
: Kind(IsParenAggInit ? EK_ParenAggInitMember : EK_Member),
Parent(Parent), Type(Member->getType()),
Variable{Member, Implicit, DefaultMemberInit} {}
/// Create the initialization entity for an array element.
InitializedEntity(ASTContext &Context, unsigned Index,
const InitializedEntity &Parent);
/// Create the initialization entity for a lambda capture.
InitializedEntity(IdentifierInfo *VarID, QualType FieldType, SourceLocation Loc)
: Kind(EK_LambdaCapture), Type(FieldType) {
new (&Capture) C;
Capture.VarID = VarID;
Capture.Location = Loc;
}
public:
/// Create the initialization entity for a variable.
static InitializedEntity InitializeVariable(VarDecl *Var) {
return InitializedEntity(Var);
}
/// Create the initialization entity for a parameter.
static InitializedEntity InitializeParameter(ASTContext &Context,
ParmVarDecl *Parm) {
return InitializeParameter(Context, Parm, Parm->getType());
}
/// Create the initialization entity for a parameter, but use
/// another type.
static InitializedEntity
InitializeParameter(ASTContext &Context, ParmVarDecl *Parm, QualType Type) {
bool Consumed = (Context.getLangOpts().ObjCAutoRefCount &&
Parm->hasAttr<NSConsumedAttr>());
InitializedEntity Entity;
Entity.Kind = EK_Parameter;
Entity.Type =
Context.getVariableArrayDecayedType(Type.getUnqualifiedType());
Entity.Parent = nullptr;
Entity.Parameter = {Parm, Consumed};
return Entity;
}
/// Create the initialization entity for a parameter that is
/// only known by its type.
static InitializedEntity InitializeParameter(ASTContext &Context,
QualType Type,
bool Consumed) {
InitializedEntity Entity;
Entity.Kind = EK_Parameter;
Entity.Type = Context.getVariableArrayDecayedType(Type);
Entity.Parent = nullptr;
Entity.Parameter = {nullptr, Consumed};
return Entity;
}
/// Create the initialization entity for a template parameter.
static InitializedEntity
InitializeTemplateParameter(QualType T, NonTypeTemplateParmDecl *Param) {
InitializedEntity Entity;
Entity.Kind = EK_TemplateParameter;
Entity.Type = T;
Entity.Parent = nullptr;
Entity.Variable = {Param, false, false};
return Entity;
}
/// Create the initialization entity for the result of a function.
static InitializedEntity InitializeResult(SourceLocation ReturnLoc,
QualType Type) {
return InitializedEntity(EK_Result, ReturnLoc, Type);
}
static InitializedEntity InitializeStmtExprResult(SourceLocation ReturnLoc,
QualType Type) {
return InitializedEntity(EK_StmtExprResult, ReturnLoc, Type);
}
static InitializedEntity InitializeBlock(SourceLocation BlockVarLoc,
QualType Type) {
return InitializedEntity(EK_BlockElement, BlockVarLoc, Type);
}
static InitializedEntity InitializeLambdaToBlock(SourceLocation BlockVarLoc,
QualType Type) {
return InitializedEntity(EK_LambdaToBlockConversionBlockElement,
BlockVarLoc, Type);
}
/// Create the initialization entity for an exception object.
static InitializedEntity InitializeException(SourceLocation ThrowLoc,
QualType Type) {
return InitializedEntity(EK_Exception, ThrowLoc, Type);
}
/// Create the initialization entity for an object allocated via new.
static InitializedEntity InitializeNew(SourceLocation NewLoc, QualType Type) {
return InitializedEntity(EK_New, NewLoc, Type);
}
/// Create the initialization entity for a temporary.
static InitializedEntity InitializeTemporary(QualType Type) {
return InitializeTemporary(nullptr, Type);
}
/// Create the initialization entity for a temporary.
static InitializedEntity InitializeTemporary(ASTContext &Context,
TypeSourceInfo *TypeInfo) {
QualType Type = TypeInfo->getType();
if (Context.getLangOpts().OpenCLCPlusPlus) {
assert(!Type.hasAddressSpace() && "Temporary already has address space!");
Type = Context.getAddrSpaceQualType(Type, LangAS::opencl_private);
}
return InitializeTemporary(TypeInfo, Type);
}
/// Create the initialization entity for a temporary.
static InitializedEntity InitializeTemporary(TypeSourceInfo *TypeInfo,
QualType Type) {
InitializedEntity Result(EK_Temporary, SourceLocation(), Type);
Result.TypeInfo = TypeInfo;
return Result;
}
/// Create the initialization entity for a related result.
static InitializedEntity InitializeRelatedResult(ObjCMethodDecl *MD,
QualType Type) {
InitializedEntity Result(EK_RelatedResult, SourceLocation(), Type);
Result.MethodDecl = MD;
return Result;
}
/// Create the initialization entity for a base class subobject.
static InitializedEntity
InitializeBase(ASTContext &Context, const CXXBaseSpecifier *Base,
bool IsInheritedVirtualBase,
const InitializedEntity *Parent = nullptr);
/// Create the initialization entity for a delegated constructor.
static InitializedEntity InitializeDelegation(QualType Type) {
return InitializedEntity(EK_Delegating, SourceLocation(), Type);
}
/// Create the initialization entity for a member subobject.
static InitializedEntity
InitializeMember(FieldDecl *Member,
const InitializedEntity *Parent = nullptr,
bool Implicit = false) {
return InitializedEntity(Member, Parent, Implicit, false);
}
/// Create the initialization entity for a member subobject.
static InitializedEntity
InitializeMember(IndirectFieldDecl *Member,
const InitializedEntity *Parent = nullptr,
bool Implicit = false) {
return InitializedEntity(Member->getAnonField(), Parent, Implicit, false);
}
/// Create the initialization entity for a member subobject initialized via
/// parenthesized aggregate init.
static InitializedEntity InitializeMemberFromParenAggInit(FieldDecl *Member) {
return InitializedEntity(Member, /*Parent=*/nullptr, /*Implicit=*/false,
/*DefaultMemberInit=*/false,
/*IsParenAggInit=*/true);
}
/// Create the initialization entity for a default member initializer.
static InitializedEntity
InitializeMemberFromDefaultMemberInitializer(FieldDecl *Member) {
return InitializedEntity(Member, nullptr, false, true);
}
/// Create the initialization entity for an array element.
static InitializedEntity InitializeElement(ASTContext &Context,
unsigned Index,
const InitializedEntity &Parent) {
return InitializedEntity(Context, Index, Parent);
}
/// Create the initialization entity for a structured binding.
static InitializedEntity InitializeBinding(VarDecl *Binding) {
return InitializedEntity(Binding, EK_Binding);
}
/// Create the initialization entity for a lambda capture.
///
/// \p VarID The name of the entity being captured, or nullptr for 'this'.
static InitializedEntity InitializeLambdaCapture(IdentifierInfo *VarID,
QualType FieldType,
SourceLocation Loc) {
return InitializedEntity(VarID, FieldType, Loc);
}
/// Create the entity for a compound literal initializer.
static InitializedEntity InitializeCompoundLiteralInit(TypeSourceInfo *TSI) {
InitializedEntity Result(EK_CompoundLiteralInit, SourceLocation(),
TSI->getType());
Result.TypeInfo = TSI;
return Result;
}
/// Determine the kind of initialization.
EntityKind getKind() const { return Kind; }
/// Retrieve the parent of the entity being initialized, when
/// the initialization itself is occurring within the context of a
/// larger initialization.
const InitializedEntity *getParent() const { return Parent; }
/// Retrieve type being initialized.
QualType getType() const { return Type; }
/// Retrieve complete type-source information for the object being
/// constructed, if known.
TypeSourceInfo *getTypeSourceInfo() const {
if (Kind == EK_Temporary || Kind == EK_CompoundLiteralInit)
return TypeInfo;
return nullptr;
}
/// Retrieve the name of the entity being initialized.
DeclarationName getName() const;
/// Retrieve the variable, parameter, or field being
/// initialized.
ValueDecl *getDecl() const;
/// Retrieve the ObjectiveC method being initialized.
ObjCMethodDecl *getMethodDecl() const { return MethodDecl; }
/// Determine whether this initialization allows the named return
/// value optimization, which also applies to thrown objects.
bool allowsNRVO() const;
bool isParameterKind() const {
return (getKind() == EK_Parameter ||
getKind() == EK_Parameter_CF_Audited);
}
bool isParamOrTemplateParamKind() const {
return isParameterKind() || getKind() == EK_TemplateParameter;
}
/// Determine whether this initialization consumes the
/// parameter.
bool isParameterConsumed() const {
assert(isParameterKind() && "Not a parameter");
return Parameter.getInt();
}
/// Retrieve the base specifier.
const CXXBaseSpecifier *getBaseSpecifier() const {
assert(getKind() == EK_Base && "Not a base specifier");
return Base.getPointer();
}
/// Return whether the base is an inherited virtual base.
bool isInheritedVirtualBase() const {
assert(getKind() == EK_Base && "Not a base specifier");
return Base.getInt();
}
/// Determine whether this is an array new with an unknown bound.
bool isVariableLengthArrayNew() const {
return getKind() == EK_New && isa_and_nonnull<IncompleteArrayType>(
getType()->getAsArrayTypeUnsafe());
}
/// Is this the implicit initialization of a member of a class from
/// a defaulted constructor?
bool isImplicitMemberInitializer() const {
return getKind() == EK_Member && Variable.IsImplicitFieldInit;
}
/// Is this the default member initializer of a member (specified inside
/// the class definition)?
bool isDefaultMemberInitializer() const {
return getKind() == EK_Member && Variable.IsDefaultMemberInit;
}
/// Determine the location of the 'return' keyword when initializing
/// the result of a function call.
SourceLocation getReturnLoc() const {
assert(getKind() == EK_Result && "No 'return' location!");
return LocAndNRVO.Location;
}
/// Determine the location of the 'throw' keyword when initializing
/// an exception object.
SourceLocation getThrowLoc() const {
assert(getKind() == EK_Exception && "No 'throw' location!");
return LocAndNRVO.Location;
}
/// If this is an array, vector, or complex number element, get the
/// element's index.
unsigned getElementIndex() const {
assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement ||
getKind() == EK_ComplexElement);
return Index;
}
/// If this is already the initializer for an array or vector
/// element, sets the element index.
void setElementIndex(unsigned Index) {
assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement ||
getKind() == EK_ComplexElement);
this->Index = Index;
}
/// For a lambda capture, return the capture's name.
StringRef getCapturedVarName() const {
assert(getKind() == EK_LambdaCapture && "Not a lambda capture!");
return Capture.VarID ? Capture.VarID->getName() : "this";
}
/// Determine the location of the capture when initializing
/// field from a captured variable in a lambda.
SourceLocation getCaptureLoc() const {
assert(getKind() == EK_LambdaCapture && "Not a lambda capture!");
return Capture.Location;
}
void setParameterCFAudited() {
Kind = EK_Parameter_CF_Audited;
}
unsigned allocateManglingNumber() const { return ++ManglingNumber; }
/// Dump a representation of the initialized entity to standard error,
/// for debugging purposes.
void dump() const;
private:
unsigned dumpImpl(raw_ostream &OS) const;
};
/// Describes the kind of initialization being performed, along with
/// location information for tokens related to the initialization (equal sign,
/// parentheses).
class InitializationKind {
public:
/// The kind of initialization being performed.
enum InitKind {
/// Direct initialization
IK_Direct,
/// Direct list-initialization
IK_DirectList,
/// Copy initialization
IK_Copy,
/// Default initialization
IK_Default,
/// Value initialization
IK_Value
};
private:
/// The context of the initialization.
enum InitContext {
/// Normal context
IC_Normal,
/// Normal context, but allows explicit conversion functionss
IC_ExplicitConvs,
/// Implicit context (value initialization)
IC_Implicit,
/// Static cast context
IC_StaticCast,
/// C-style cast context
IC_CStyleCast,
/// Functional cast context
IC_FunctionalCast
};
/// The kind of initialization being performed.
InitKind Kind : 8;
/// The context of the initialization.
InitContext Context : 8;
/// The source locations involved in the initialization.
SourceLocation Locations[3];
InitializationKind(InitKind Kind, InitContext Context, SourceLocation Loc1,
SourceLocation Loc2, SourceLocation Loc3)
: Kind(Kind), Context(Context) {
Locations[0] = Loc1;
Locations[1] = Loc2;
Locations[2] = Loc3;
}
public:
/// Create a direct initialization.
static InitializationKind CreateDirect(SourceLocation InitLoc,
SourceLocation LParenLoc,
SourceLocation RParenLoc) {
return InitializationKind(IK_Direct, IC_Normal,
InitLoc, LParenLoc, RParenLoc);
}
static InitializationKind CreateDirectList(SourceLocation InitLoc) {
return InitializationKind(IK_DirectList, IC_Normal, InitLoc, InitLoc,
InitLoc);
}
static InitializationKind CreateDirectList(SourceLocation InitLoc,
SourceLocation LBraceLoc,
SourceLocation RBraceLoc) {
return InitializationKind(IK_DirectList, IC_Normal, InitLoc, LBraceLoc,
RBraceLoc);
}
/// Create a direct initialization due to a cast that isn't a C-style
/// or functional cast.
static InitializationKind CreateCast(SourceRange TypeRange) {
return InitializationKind(IK_Direct, IC_StaticCast, TypeRange.getBegin(),
TypeRange.getBegin(), TypeRange.getEnd());
}
/// Create a direct initialization for a C-style cast.
static InitializationKind CreateCStyleCast(SourceLocation StartLoc,
SourceRange TypeRange,
bool InitList) {
// C++ cast syntax doesn't permit init lists, but C compound literals are
// exactly that.
return InitializationKind(InitList ? IK_DirectList : IK_Direct,
IC_CStyleCast, StartLoc, TypeRange.getBegin(),
TypeRange.getEnd());
}
/// Create a direct initialization for a functional cast.
static InitializationKind CreateFunctionalCast(SourceRange TypeRange,
bool InitList) {
return InitializationKind(InitList ? IK_DirectList : IK_Direct,
IC_FunctionalCast, TypeRange.getBegin(),
TypeRange.getBegin(), TypeRange.getEnd());
}
/// Create a copy initialization.
static InitializationKind CreateCopy(SourceLocation InitLoc,
SourceLocation EqualLoc,
bool AllowExplicitConvs = false) {
return InitializationKind(IK_Copy,
AllowExplicitConvs? IC_ExplicitConvs : IC_Normal,
InitLoc, EqualLoc, EqualLoc);
}
/// Create a default initialization.
static InitializationKind CreateDefault(SourceLocation InitLoc) {
return InitializationKind(IK_Default, IC_Normal, InitLoc, InitLoc, InitLoc);
}
/// Create a value initialization.
static InitializationKind CreateValue(SourceLocation InitLoc,
SourceLocation LParenLoc,
SourceLocation RParenLoc,
bool isImplicit = false) {
return InitializationKind(IK_Value, isImplicit ? IC_Implicit : IC_Normal,
InitLoc, LParenLoc, RParenLoc);
}
/// Create an initialization from an initializer (which, for direct
/// initialization from a parenthesized list, will be a ParenListExpr).
static InitializationKind CreateForInit(SourceLocation Loc, bool DirectInit,
Expr *Init) {
if (!Init) return CreateDefault(Loc);
if (!DirectInit)
return CreateCopy(Loc, Init->getBeginLoc());
if (isa<InitListExpr>(Init))
return CreateDirectList(Loc, Init->getBeginLoc(), Init->getEndLoc());
return CreateDirect(Loc, Init->getBeginLoc(), Init->getEndLoc());
}
/// Determine the initialization kind.
InitKind getKind() const {
return Kind;
}
/// Determine whether this initialization is an explicit cast.
bool isExplicitCast() const {
return Context >= IC_StaticCast;
}
/// Determine whether this initialization is a static cast.
bool isStaticCast() const { return Context == IC_StaticCast; }
/// Determine whether this initialization is a C-style cast.
bool isCStyleOrFunctionalCast() const {
return Context >= IC_CStyleCast;
}
/// Determine whether this is a C-style cast.
bool isCStyleCast() const {
return Context == IC_CStyleCast;
}
/// Determine whether this is a functional-style cast.
bool isFunctionalCast() const {
return Context == IC_FunctionalCast;
}
/// Determine whether this initialization is an implicit
/// value-initialization, e.g., as occurs during aggregate
/// initialization.
bool isImplicitValueInit() const { return Context == IC_Implicit; }
/// Retrieve the location at which initialization is occurring.
SourceLocation getLocation() const { return Locations[0]; }
/// Retrieve the source range that covers the initialization.
SourceRange getRange() const {
return SourceRange(Locations[0], Locations[2]);
}
/// Retrieve the location of the equal sign for copy initialization
/// (if present).
SourceLocation getEqualLoc() const {
assert(Kind == IK_Copy && "Only copy initialization has an '='");
return Locations[1];
}
bool isCopyInit() const { return Kind == IK_Copy; }
/// Retrieve whether this initialization allows the use of explicit
/// constructors.
bool AllowExplicit() const { return !isCopyInit(); }
/// Retrieve whether this initialization allows the use of explicit
/// conversion functions when binding a reference. If the reference is the
/// first parameter in a copy or move constructor, such conversions are
/// permitted even though we are performing copy-initialization.
bool allowExplicitConversionFunctionsInRefBinding() const {
return !isCopyInit() || Context == IC_ExplicitConvs;
}
/// Determine whether this initialization has a source range containing the
/// locations of open and closing parentheses or braces.
bool hasParenOrBraceRange() const {
return Kind == IK_Direct || Kind == IK_Value || Kind == IK_DirectList;
}
/// Retrieve the source range containing the locations of the open
/// and closing parentheses or braces for value, direct, and direct list
/// initializations.
SourceRange getParenOrBraceRange() const {
assert(hasParenOrBraceRange() && "Only direct, value, and direct-list "
"initialization have parentheses or "
"braces");
return SourceRange(Locations[1], Locations[2]);
}
};
/// Describes the sequence of initializations required to initialize
/// a given object or reference with a set of arguments.
class InitializationSequence {
public:
/// Describes the kind of initialization sequence computed.
enum SequenceKind {
/// A failed initialization sequence. The failure kind tells what
/// happened.
FailedSequence = 0,
/// A dependent initialization, which could not be
/// type-checked due to the presence of dependent types or
/// dependently-typed expressions.
DependentSequence,
/// A normal sequence.
NormalSequence
};
/// Describes the kind of a particular step in an initialization
/// sequence.
enum StepKind {
/// Resolve the address of an overloaded function to a specific
/// function declaration.
SK_ResolveAddressOfOverloadedFunction,
/// Perform a derived-to-base cast, producing an rvalue.
SK_CastDerivedToBasePRValue,
/// Perform a derived-to-base cast, producing an xvalue.
SK_CastDerivedToBaseXValue,
/// Perform a derived-to-base cast, producing an lvalue.
SK_CastDerivedToBaseLValue,
/// Reference binding to an lvalue.
SK_BindReference,
/// Reference binding to a temporary.
SK_BindReferenceToTemporary,
/// An optional copy of a temporary object to another
/// temporary object, which is permitted (but not required) by
/// C++98/03 but not C++0x.
SK_ExtraneousCopyToTemporary,
/// Direct-initialization from a reference-related object in the
/// final stage of class copy-initialization.
SK_FinalCopy,
/// Perform a user-defined conversion, either via a conversion
/// function or via a constructor.
SK_UserConversion,
/// Perform a qualification conversion, producing a prvalue.
SK_QualificationConversionPRValue,
/// Perform a qualification conversion, producing an xvalue.
SK_QualificationConversionXValue,
/// Perform a qualification conversion, producing an lvalue.
SK_QualificationConversionLValue,
/// Perform a function reference conversion, see [dcl.init.ref]p4.
SK_FunctionReferenceConversion,
/// Perform a conversion adding _Atomic to a type.
SK_AtomicConversion,
/// Perform an implicit conversion sequence.
SK_ConversionSequence,
/// Perform an implicit conversion sequence without narrowing.
SK_ConversionSequenceNoNarrowing,
/// Perform list-initialization without a constructor.
SK_ListInitialization,
/// Unwrap the single-element initializer list for a reference.
SK_UnwrapInitList,
/// Rewrap the single-element initializer list for a reference.
SK_RewrapInitList,
/// Perform initialization via a constructor.
SK_ConstructorInitialization,
/// Perform initialization via a constructor, taking arguments from
/// a single InitListExpr.
SK_ConstructorInitializationFromList,
/// Zero-initialize the object
SK_ZeroInitialization,
/// C assignment
SK_CAssignment,
/// Initialization by string
SK_StringInit,
/// An initialization that "converts" an Objective-C object
/// (not a point to an object) to another Objective-C object type.
SK_ObjCObjectConversion,
/// Array indexing for initialization by elementwise copy.
SK_ArrayLoopIndex,
/// Array initialization by elementwise copy.
SK_ArrayLoopInit,
/// Array initialization (from an array rvalue).
SK_ArrayInit,
/// Array initialization (from an array rvalue) as a GNU extension.
SK_GNUArrayInit,
/// Array initialization from a parenthesized initializer list.
/// This is a GNU C++ extension.
SK_ParenthesizedArrayInit,
/// Pass an object by indirect copy-and-restore.
SK_PassByIndirectCopyRestore,
/// Pass an object by indirect restore.
SK_PassByIndirectRestore,
/// Produce an Objective-C object pointer.
SK_ProduceObjCObject,
/// Construct a std::initializer_list from an initializer list.
SK_StdInitializerList,
/// Perform initialization via a constructor taking a single
/// std::initializer_list argument.
SK_StdInitializerListConstructorCall,
/// Initialize an OpenCL sampler from an integer.
SK_OCLSamplerInit,
/// Initialize an opaque OpenCL type (event_t, queue_t, etc.) with zero
SK_OCLZeroOpaqueType,
/// Initialize an aggreagate with parenthesized list of values.
/// This is a C++20 feature.
SK_ParenthesizedListInit
};
/// A single step in the initialization sequence.
class Step {
public:
/// The kind of conversion or initialization step we are taking.
StepKind Kind;
// The type that results from this initialization.
QualType Type;
struct F {
bool HadMultipleCandidates;
FunctionDecl *Function;
DeclAccessPair FoundDecl;
};
union {
/// When Kind == SK_ResolvedOverloadedFunction or Kind ==
/// SK_UserConversion, the function that the expression should be
/// resolved to or the conversion function to call, respectively.
/// When Kind == SK_ConstructorInitialization or SK_ListConstruction,
/// the constructor to be called.
///
/// Always a FunctionDecl, plus a Boolean flag telling if it was
/// selected from an overloaded set having size greater than 1.
/// For conversion decls, the naming class is the source type.
/// For construct decls, the naming class is the target type.
struct F Function;
/// When Kind = SK_ConversionSequence, the implicit conversion
/// sequence.
ImplicitConversionSequence *ICS;
/// When Kind = SK_RewrapInitList, the syntactic form of the
/// wrapping list.
InitListExpr *WrappingSyntacticList;
};
void Destroy();
};
private:
/// The kind of initialization sequence computed.
enum SequenceKind SequenceKind;
/// Steps taken by this initialization.
SmallVector<Step, 4> Steps;
public:
/// Describes why initialization failed.
enum FailureKind {
/// Too many initializers provided for a reference.
FK_TooManyInitsForReference,
/// Reference initialized from a parenthesized initializer list.
FK_ParenthesizedListInitForReference,
/// Array must be initialized with an initializer list.
FK_ArrayNeedsInitList,
/// Array must be initialized with an initializer list or a
/// string literal.
FK_ArrayNeedsInitListOrStringLiteral,
/// Array must be initialized with an initializer list or a
/// wide string literal.
FK_ArrayNeedsInitListOrWideStringLiteral,
/// Initializing a wide char array with narrow string literal.
FK_NarrowStringIntoWideCharArray,
/// Initializing char array with wide string literal.
FK_WideStringIntoCharArray,
/// Initializing wide char array with incompatible wide string
/// literal.
FK_IncompatWideStringIntoWideChar,
/// Initializing char8_t array with plain string literal.
FK_PlainStringIntoUTF8Char,
/// Initializing char array with UTF-8 string literal.
FK_UTF8StringIntoPlainChar,
/// Array type mismatch.
FK_ArrayTypeMismatch,
/// Non-constant array initializer
FK_NonConstantArrayInit,
/// Cannot resolve the address of an overloaded function.
FK_AddressOfOverloadFailed,
/// Overloading due to reference initialization failed.
FK_ReferenceInitOverloadFailed,
/// Non-const lvalue reference binding to a temporary.
FK_NonConstLValueReferenceBindingToTemporary,
/// Non-const lvalue reference binding to a bit-field.
FK_NonConstLValueReferenceBindingToBitfield,
/// Non-const lvalue reference binding to a vector element.
FK_NonConstLValueReferenceBindingToVectorElement,
/// Non-const lvalue reference binding to a matrix element.
FK_NonConstLValueReferenceBindingToMatrixElement,
/// Non-const lvalue reference binding to an lvalue of unrelated
/// type.
FK_NonConstLValueReferenceBindingToUnrelated,
/// Rvalue reference binding to an lvalue.
FK_RValueReferenceBindingToLValue,
/// Reference binding drops qualifiers.
FK_ReferenceInitDropsQualifiers,
/// Reference with mismatching address space binding to temporary.
FK_ReferenceAddrspaceMismatchTemporary,
/// Reference binding failed.
FK_ReferenceInitFailed,
/// Implicit conversion failed.
FK_ConversionFailed,
/// Implicit conversion failed.
FK_ConversionFromPropertyFailed,
/// Too many initializers for scalar
FK_TooManyInitsForScalar,
/// Scalar initialized from a parenthesized initializer list.
FK_ParenthesizedListInitForScalar,
/// Reference initialization from an initializer list
FK_ReferenceBindingToInitList,
/// Initialization of some unused destination type with an
/// initializer list.
FK_InitListBadDestinationType,
/// Overloading for a user-defined conversion failed.
FK_UserConversionOverloadFailed,
/// Overloading for initialization by constructor failed.
FK_ConstructorOverloadFailed,
/// Overloading for list-initialization by constructor failed.
FK_ListConstructorOverloadFailed,
/// Default-initialization of a 'const' object.
FK_DefaultInitOfConst,
/// Initialization of an incomplete type.
FK_Incomplete,
/// Variable-length array must not have an initializer.
FK_VariableLengthArrayHasInitializer,
/// List initialization failed at some point.
FK_ListInitializationFailed,
/// Initializer has a placeholder type which cannot be
/// resolved by initialization.
FK_PlaceholderType,
/// Trying to take the address of a function that doesn't support
/// having its address taken.
FK_AddressOfUnaddressableFunction,
/// List-copy-initialization chose an explicit constructor.
FK_ExplicitConstructor,
/// Parenthesized list initialization failed at some point.
/// This is a C++20 feature.
FK_ParenthesizedListInitFailed,
};
private:
/// The reason why initialization failed.
FailureKind Failure;
/// The failed result of overload resolution.
OverloadingResult FailedOverloadResult;
/// The candidate set created when initialization failed.
OverloadCandidateSet FailedCandidateSet;
/// The incomplete type that caused a failure.
QualType FailedIncompleteType;
/// The fixit that needs to be applied to make this initialization
/// succeed.
std::string ZeroInitializationFixit;
SourceLocation ZeroInitializationFixitLoc;
public:
/// Call for initializations are invalid but that would be valid
/// zero initialzations if Fixit was applied.
void SetZeroInitializationFixit(const std::string& Fixit, SourceLocation L) {
ZeroInitializationFixit = Fixit;
ZeroInitializationFixitLoc = L;
}
private:
/// Prints a follow-up note that highlights the location of
/// the initialized entity, if it's remote.
void PrintInitLocationNote(Sema &S, const InitializedEntity &Entity);
public:
/// Try to perform initialization of the given entity, creating a
/// record of the steps required to perform the initialization.
///
/// The generated initialization sequence will either contain enough
/// information to diagnose
///
/// \param S the semantic analysis object.
///
/// \param Entity the entity being initialized.
///
/// \param Kind the kind of initialization being performed.
///
/// \param Args the argument(s) provided for initialization.
///
/// \param TopLevelOfInitList true if we are initializing from an expression
/// at the top level inside an initializer list. This disallows
/// narrowing conversions in C++11 onwards.
/// \param TreatUnavailableAsInvalid true if we want to treat unavailable
/// as invalid.
InitializationSequence(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
MultiExprArg Args,
bool TopLevelOfInitList = false,
bool TreatUnavailableAsInvalid = true);
void InitializeFrom(Sema &S, const InitializedEntity &Entity,
const InitializationKind &Kind, MultiExprArg Args,
bool TopLevelOfInitList, bool TreatUnavailableAsInvalid);
~InitializationSequence();
/// Perform the actual initialization of the given entity based on
/// the computed initialization sequence.
///
/// \param S the semantic analysis object.
///
/// \param Entity the entity being initialized.
///
/// \param Kind the kind of initialization being performed.
///
/// \param Args the argument(s) provided for initialization, ownership of
/// which is transferred into the routine.
///
/// \param ResultType if non-NULL, will be set to the type of the
/// initialized object, which is the type of the declaration in most
/// cases. However, when the initialized object is a variable of
/// incomplete array type and the initializer is an initializer
/// list, this type will be set to the completed array type.
///
/// \returns an expression that performs the actual object initialization, if
/// the initialization is well-formed. Otherwise, emits diagnostics
/// and returns an invalid expression.
ExprResult Perform(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
MultiExprArg Args,
QualType *ResultType = nullptr);
/// Diagnose an potentially-invalid initialization sequence.
///
/// \returns true if the initialization sequence was ill-formed,
/// false otherwise.
bool Diagnose(Sema &S,
const InitializedEntity &Entity,
const InitializationKind &Kind,
ArrayRef<Expr *> Args);
/// Determine the kind of initialization sequence computed.
enum SequenceKind getKind() const { return SequenceKind; }
/// Set the kind of sequence computed.
void setSequenceKind(enum SequenceKind SK) { SequenceKind = SK; }
/// Determine whether the initialization sequence is valid.
explicit operator bool() const { return !Failed(); }
/// Determine whether the initialization sequence is invalid.
bool Failed() const { return SequenceKind == FailedSequence; }
using step_iterator = SmallVectorImpl<Step>::const_iterator;
step_iterator step_begin() const { return Steps.begin(); }
step_iterator step_end() const { return Steps.end(); }
using step_range = llvm::iterator_range<step_iterator>;
step_range steps() const { return {step_begin(), step_end()}; }
/// Determine whether this initialization is a direct reference
/// binding (C++ [dcl.init.ref]).
bool isDirectReferenceBinding() const;
/// Determine whether this initialization failed due to an ambiguity.
bool isAmbiguous() const;
/// Determine whether this initialization is direct call to a
/// constructor.
bool isConstructorInitialization() const;
/// Add a new step in the initialization that resolves the address
/// of an overloaded function to a specific function declaration.
///
/// \param Function the function to which the overloaded function reference
/// resolves.
void AddAddressOverloadResolutionStep(FunctionDecl *Function,
DeclAccessPair Found,
bool HadMultipleCandidates);
/// Add a new step in the initialization that performs a derived-to-
/// base cast.
///
/// \param BaseType the base type to which we will be casting.
///
/// \param Category Indicates whether the result will be treated as an
/// rvalue, an xvalue, or an lvalue.
void AddDerivedToBaseCastStep(QualType BaseType,
ExprValueKind Category);
/// Add a new step binding a reference to an object.
///
/// \param BindingTemporary True if we are binding a reference to a temporary
/// object (thereby extending its lifetime); false if we are binding to an
/// lvalue or an lvalue treated as an rvalue.
void AddReferenceBindingStep(QualType T, bool BindingTemporary);
/// Add a new step that makes an extraneous copy of the input
/// to a temporary of the same class type.
///
/// This extraneous copy only occurs during reference binding in
/// C++98/03, where we are permitted (but not required) to introduce
/// an extra copy. At a bare minimum, we must check that we could
/// call the copy constructor, and produce a diagnostic if the copy
/// constructor is inaccessible or no copy constructor matches.
//
/// \param T The type of the temporary being created.
void AddExtraneousCopyToTemporary(QualType T);
/// Add a new step that makes a copy of the input to an object of
/// the given type, as the final step in class copy-initialization.
void AddFinalCopy(QualType T);
/// Add a new step invoking a conversion function, which is either
/// a constructor or a conversion function.
void AddUserConversionStep(FunctionDecl *Function,
DeclAccessPair FoundDecl,
QualType T,
bool HadMultipleCandidates);
/// Add a new step that performs a qualification conversion to the
/// given type.
void AddQualificationConversionStep(QualType Ty,
ExprValueKind Category);
/// Add a new step that performs a function reference conversion to the
/// given type.
void AddFunctionReferenceConversionStep(QualType Ty);
/// Add a new step that performs conversion from non-atomic to atomic
/// type.
void AddAtomicConversionStep(QualType Ty);
/// Add a new step that applies an implicit conversion sequence.
void AddConversionSequenceStep(const ImplicitConversionSequence &ICS,
QualType T, bool TopLevelOfInitList = false);
/// Add a list-initialization step.
void AddListInitializationStep(QualType T);
/// Add a constructor-initialization step.
///
/// \param FromInitList The constructor call is syntactically an initializer
/// list.
/// \param AsInitList The constructor is called as an init list constructor.
void AddConstructorInitializationStep(DeclAccessPair FoundDecl,
CXXConstructorDecl *Constructor,
QualType T,
bool HadMultipleCandidates,
bool FromInitList, bool AsInitList);
/// Add a zero-initialization step.
void AddZeroInitializationStep(QualType T);
/// Add a C assignment step.
//
// FIXME: It isn't clear whether this should ever be needed;
// ideally, we would handle everything needed in C in the common
// path. However, that isn't the case yet.
void AddCAssignmentStep(QualType T);
/// Add a string init step.
void AddStringInitStep(QualType T);
/// Add an Objective-C object conversion step, which is
/// always a no-op.
void AddObjCObjectConversionStep(QualType T);
/// Add an array initialization loop step.
void AddArrayInitLoopStep(QualType T, QualType EltTy);
/// Add an array initialization step.
void AddArrayInitStep(QualType T, bool IsGNUExtension);
/// Add a parenthesized array initialization step.
void AddParenthesizedArrayInitStep(QualType T);
/// Add a step to pass an object by indirect copy-restore.
void AddPassByIndirectCopyRestoreStep(QualType T, bool shouldCopy);
/// Add a step to "produce" an Objective-C object (by
/// retaining it).
void AddProduceObjCObjectStep(QualType T);
/// Add a step to construct a std::initializer_list object from an
/// initializer list.
void AddStdInitializerListConstructionStep(QualType T);
/// Add a step to initialize an OpenCL sampler from an integer
/// constant.
void AddOCLSamplerInitStep(QualType T);
/// Add a step to initialzie an OpenCL opaque type (event_t, queue_t, etc.)
/// from a zero constant.
void AddOCLZeroOpaqueTypeStep(QualType T);
void AddParenthesizedListInitStep(QualType T);
/// Add steps to unwrap a initializer list for a reference around a
/// single element and rewrap it at the end.
void RewrapReferenceInitList(QualType T, InitListExpr *Syntactic);
/// Note that this initialization sequence failed.
void SetFailed(FailureKind Failure) {
SequenceKind = FailedSequence;
this->Failure = Failure;
assert((Failure != FK_Incomplete || !FailedIncompleteType.isNull()) &&
"Incomplete type failure requires a type!");
}
/// Note that this initialization sequence failed due to failed
/// overload resolution.
void SetOverloadFailure(FailureKind Failure, OverloadingResult Result);
/// Retrieve a reference to the candidate set when overload
/// resolution fails.
OverloadCandidateSet &getFailedCandidateSet() {
return FailedCandidateSet;
}
/// Get the overloading result, for when the initialization
/// sequence failed due to a bad overload.
OverloadingResult getFailedOverloadResult() const {
return FailedOverloadResult;
}
/// Note that this initialization sequence failed due to an
/// incomplete type.
void setIncompleteTypeFailure(QualType IncompleteType) {
FailedIncompleteType = IncompleteType;
SetFailed(FK_Incomplete);
}
/// Determine why initialization failed.
FailureKind getFailureKind() const {
assert(Failed() && "Not an initialization failure!");
return Failure;
}
/// Dump a representation of this initialization sequence to
/// the given stream, for debugging purposes.
void dump(raw_ostream &OS) const;
/// Dump a representation of this initialization sequence to
/// standard error, for debugging purposes.
void dump() const;
};
} // namespace clang
#endif // LLVM_CLANG_SEMA_INITIALIZATION_H