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//===- Lookup.h - Classes for name lookup -----------------------*- 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 defines the LookupResult class, which is integral to
// Sema's name-lookup subsystem.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_SEMA_LOOKUP_H
#define LLVM_CLANG_SEMA_LOOKUP_H
#include "clang/AST/Decl.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/Type.h"
#include "clang/AST/UnresolvedSet.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Sema/Sema.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Casting.h"
#include <cassert>
#include <optional>
#include <utility>
namespace clang {
class CXXBasePaths;
/// Represents the results of name lookup.
///
/// An instance of the LookupResult class captures the results of a
/// single name lookup, which can return no result (nothing found),
/// a single declaration, a set of overloaded functions, or an
/// ambiguity. Use the getKind() method to determine which of these
/// results occurred for a given lookup.
class LookupResult {
public:
enum LookupResultKind {
/// No entity found met the criteria.
NotFound = 0,
/// No entity found met the criteria within the current
/// instantiation,, but there were dependent base classes of the
/// current instantiation that could not be searched.
NotFoundInCurrentInstantiation,
/// Name lookup found a single declaration that met the
/// criteria. getFoundDecl() will return this declaration.
Found,
/// Name lookup found a set of overloaded functions that
/// met the criteria.
FoundOverloaded,
/// Name lookup found an unresolvable value declaration
/// and cannot yet complete. This only happens in C++ dependent
/// contexts with dependent using declarations.
FoundUnresolvedValue,
/// Name lookup results in an ambiguity; use
/// getAmbiguityKind to figure out what kind of ambiguity
/// we have.
Ambiguous
};
enum AmbiguityKind {
/// Name lookup results in an ambiguity because multiple
/// entities that meet the lookup criteria were found in
/// subobjects of different types. For example:
/// @code
/// struct A { void f(int); }
/// struct B { void f(double); }
/// struct C : A, B { };
/// void test(C c) {
/// c.f(0); // error: A::f and B::f come from subobjects of different
/// // types. overload resolution is not performed.
/// }
/// @endcode
AmbiguousBaseSubobjectTypes,
/// Name lookup results in an ambiguity because multiple
/// nonstatic entities that meet the lookup criteria were found
/// in different subobjects of the same type. For example:
/// @code
/// struct A { int x; };
/// struct B : A { };
/// struct C : A { };
/// struct D : B, C { };
/// int test(D d) {
/// return d.x; // error: 'x' is found in two A subobjects (of B and C)
/// }
/// @endcode
AmbiguousBaseSubobjects,
/// Name lookup results in an ambiguity because multiple definitions
/// of entity that meet the lookup criteria were found in different
/// declaration contexts.
/// @code
/// namespace A {
/// int i;
/// namespace B { int i; }
/// int test() {
/// using namespace B;
/// return i; // error 'i' is found in namespace A and A::B
/// }
/// }
/// @endcode
AmbiguousReference,
/// Name lookup results in an ambiguity because multiple placeholder
/// variables were found in the same scope.
/// @code
/// void f() {
/// int _ = 0;
/// int _ = 0;
/// return _; // ambiguous use of placeholder variable
/// }
/// @endcode
AmbiguousReferenceToPlaceholderVariable,
/// Name lookup results in an ambiguity because an entity with a
/// tag name was hidden by an entity with an ordinary name from
/// a different context.
/// @code
/// namespace A { struct Foo {}; }
/// namespace B { void Foo(); }
/// namespace C {
/// using namespace A;
/// using namespace B;
/// }
/// void test() {
/// C::Foo(); // error: tag 'A::Foo' is hidden by an object in a
/// // different namespace
/// }
/// @endcode
AmbiguousTagHiding
};
/// A little identifier for flagging temporary lookup results.
enum TemporaryToken {
Temporary
};
using iterator = UnresolvedSetImpl::iterator;
LookupResult(
Sema &SemaRef, const DeclarationNameInfo &NameInfo,
Sema::LookupNameKind LookupKind,
RedeclarationKind Redecl = RedeclarationKind::NotForRedeclaration)
: SemaPtr(&SemaRef), NameInfo(NameInfo), LookupKind(LookupKind),
Redecl(Redecl != RedeclarationKind::NotForRedeclaration),
ExternalRedecl(Redecl == RedeclarationKind::ForExternalRedeclaration),
DiagnoseAccess(Redecl == RedeclarationKind::NotForRedeclaration),
DiagnoseAmbiguous(Redecl == RedeclarationKind::NotForRedeclaration) {
configure();
}
// TODO: consider whether this constructor should be restricted to take
// as input a const IdentifierInfo* (instead of Name),
// forcing other cases towards the constructor taking a DNInfo.
LookupResult(
Sema &SemaRef, DeclarationName Name, SourceLocation NameLoc,
Sema::LookupNameKind LookupKind,
RedeclarationKind Redecl = RedeclarationKind::NotForRedeclaration)
: SemaPtr(&SemaRef), NameInfo(Name, NameLoc), LookupKind(LookupKind),
Redecl(Redecl != RedeclarationKind::NotForRedeclaration),
ExternalRedecl(Redecl == RedeclarationKind::ForExternalRedeclaration),
DiagnoseAccess(Redecl == RedeclarationKind::NotForRedeclaration),
DiagnoseAmbiguous(Redecl == RedeclarationKind::NotForRedeclaration) {
configure();
}
/// Creates a temporary lookup result, initializing its core data
/// using the information from another result. Diagnostics are always
/// disabled.
LookupResult(TemporaryToken _, const LookupResult &Other)
: SemaPtr(Other.SemaPtr), NameInfo(Other.NameInfo),
LookupKind(Other.LookupKind), IDNS(Other.IDNS), Redecl(Other.Redecl),
ExternalRedecl(Other.ExternalRedecl), HideTags(Other.HideTags),
AllowHidden(Other.AllowHidden),
TemplateNameLookup(Other.TemplateNameLookup) {}
// FIXME: Remove these deleted methods once the default build includes
// -Wdeprecated.
LookupResult(const LookupResult &) = delete;
LookupResult &operator=(const LookupResult &) = delete;
LookupResult(LookupResult &&Other)
: ResultKind(std::move(Other.ResultKind)),
Ambiguity(std::move(Other.Ambiguity)), Decls(std::move(Other.Decls)),
Paths(std::move(Other.Paths)),
NamingClass(std::move(Other.NamingClass)),
BaseObjectType(std::move(Other.BaseObjectType)),
SemaPtr(std::move(Other.SemaPtr)), NameInfo(std::move(Other.NameInfo)),
NameContextRange(std::move(Other.NameContextRange)),
LookupKind(std::move(Other.LookupKind)), IDNS(std::move(Other.IDNS)),
Redecl(std::move(Other.Redecl)),
ExternalRedecl(std::move(Other.ExternalRedecl)),
HideTags(std::move(Other.HideTags)),
DiagnoseAccess(std::move(Other.DiagnoseAccess)),
DiagnoseAmbiguous(std::move(Other.DiagnoseAmbiguous)),
AllowHidden(std::move(Other.AllowHidden)),
Shadowed(std::move(Other.Shadowed)),
TemplateNameLookup(std::move(Other.TemplateNameLookup)) {
Other.Paths = nullptr;
Other.DiagnoseAccess = false;
Other.DiagnoseAmbiguous = false;
}
LookupResult &operator=(LookupResult &&Other) {
ResultKind = std::move(Other.ResultKind);
Ambiguity = std::move(Other.Ambiguity);
Decls = std::move(Other.Decls);
Paths = std::move(Other.Paths);
NamingClass = std::move(Other.NamingClass);
BaseObjectType = std::move(Other.BaseObjectType);
SemaPtr = std::move(Other.SemaPtr);
NameInfo = std::move(Other.NameInfo);
NameContextRange = std::move(Other.NameContextRange);
LookupKind = std::move(Other.LookupKind);
IDNS = std::move(Other.IDNS);
Redecl = std::move(Other.Redecl);
ExternalRedecl = std::move(Other.ExternalRedecl);
HideTags = std::move(Other.HideTags);
DiagnoseAccess = std::move(Other.DiagnoseAccess);
DiagnoseAmbiguous = std::move(Other.DiagnoseAmbiguous);
AllowHidden = std::move(Other.AllowHidden);
Shadowed = std::move(Other.Shadowed);
TemplateNameLookup = std::move(Other.TemplateNameLookup);
Other.Paths = nullptr;
Other.DiagnoseAccess = false;
Other.DiagnoseAmbiguous = false;
return *this;
}
~LookupResult() {
if (DiagnoseAccess)
diagnoseAccess();
if (DiagnoseAmbiguous)
diagnoseAmbiguous();
if (Paths) deletePaths(Paths);
}
/// Gets the name info to look up.
const DeclarationNameInfo &getLookupNameInfo() const {
return NameInfo;
}
/// Sets the name info to look up.
void setLookupNameInfo(const DeclarationNameInfo &NameInfo) {
this->NameInfo = NameInfo;
}
/// Gets the name to look up.
DeclarationName getLookupName() const {
return NameInfo.getName();
}
/// Sets the name to look up.
void setLookupName(DeclarationName Name) {
NameInfo.setName(Name);
}
/// Gets the kind of lookup to perform.
Sema::LookupNameKind getLookupKind() const {
return LookupKind;
}
/// True if this lookup is just looking for an existing declaration.
bool isForRedeclaration() const {
return Redecl;
}
/// True if this lookup is just looking for an existing declaration to link
/// against a declaration with external linkage.
bool isForExternalRedeclaration() const {
return ExternalRedecl;
}
RedeclarationKind redeclarationKind() const {
return ExternalRedecl ? RedeclarationKind::ForExternalRedeclaration
: Redecl ? RedeclarationKind::ForVisibleRedeclaration
: RedeclarationKind::NotForRedeclaration;
}
/// Specify whether hidden declarations are visible, e.g.,
/// for recovery reasons.
void setAllowHidden(bool AH) {
AllowHidden = AH;
}
/// Determine whether this lookup is permitted to see hidden
/// declarations, such as those in modules that have not yet been imported.
bool isHiddenDeclarationVisible(NamedDecl *ND) const {
return AllowHidden ||
(isForExternalRedeclaration() && ND->isExternallyDeclarable());
}
/// Sets whether tag declarations should be hidden by non-tag
/// declarations during resolution. The default is true.
void setHideTags(bool Hide) {
HideTags = Hide;
}
/// Sets whether this is a template-name lookup. For template-name lookups,
/// injected-class-names are treated as naming a template rather than a
/// template specialization.
void setTemplateNameLookup(bool TemplateName) {
TemplateNameLookup = TemplateName;
}
bool isTemplateNameLookup() const { return TemplateNameLookup; }
bool isAmbiguous() const {
return getResultKind() == Ambiguous;
}
/// Determines if this names a single result which is not an
/// unresolved value using decl. If so, it is safe to call
/// getFoundDecl().
bool isSingleResult() const {
return getResultKind() == Found;
}
/// Determines if the results are overloaded.
bool isOverloadedResult() const {
return getResultKind() == FoundOverloaded;
}
bool isUnresolvableResult() const {
return getResultKind() == FoundUnresolvedValue;
}
LookupResultKind getResultKind() const {
assert(checkDebugAssumptions());
return ResultKind;
}
AmbiguityKind getAmbiguityKind() const {
assert(isAmbiguous());
return Ambiguity;
}
const UnresolvedSetImpl &asUnresolvedSet() const {
return Decls;
}
iterator begin() const { return iterator(Decls.begin()); }
iterator end() const { return iterator(Decls.end()); }
/// Return true if no decls were found
bool empty() const { return Decls.empty(); }
/// Return the base paths structure that's associated with
/// these results, or null if none is.
CXXBasePaths *getBasePaths() const {
return Paths;
}
/// Determine whether the given declaration is visible to the
/// program.
static bool isVisible(Sema &SemaRef, NamedDecl *D);
static bool isReachable(Sema &SemaRef, NamedDecl *D);
static bool isAcceptable(Sema &SemaRef, NamedDecl *D,
Sema::AcceptableKind Kind) {
return Kind == Sema::AcceptableKind::Visible ? isVisible(SemaRef, D)
: isReachable(SemaRef, D);
}
/// Determine whether this lookup is permitted to see the declaration.
/// Note that a reachable but not visible declaration inhabiting a namespace
/// is not allowed to be seen during name lookup.
///
/// For example:
/// ```
/// // m.cppm
/// export module m;
/// struct reachable { int v; }
/// export auto func() { return reachable{43}; }
/// // Use.cpp
/// import m;
/// auto Use() {
/// // Not valid. We couldn't see reachable here.
/// // So isAvailableForLookup would return false when we look
/// up 'reachable' here.
/// // return reachable(43).v;
/// // Valid. The field name 'v' is allowed during name lookup.
/// // So isAvailableForLookup would return true when we look up 'v' here.
/// return func().v;
/// }
/// ```
static bool isAvailableForLookup(Sema &SemaRef, NamedDecl *ND);
/// Retrieve the accepted (re)declaration of the given declaration,
/// if there is one.
NamedDecl *getAcceptableDecl(NamedDecl *D) const {
if (!D->isInIdentifierNamespace(IDNS))
return nullptr;
if (isAvailableForLookup(getSema(), D) || isHiddenDeclarationVisible(D))
return D;
return getAcceptableDeclSlow(D);
}
private:
static bool isAcceptableSlow(Sema &SemaRef, NamedDecl *D,
Sema::AcceptableKind Kind);
static bool isReachableSlow(Sema &SemaRef, NamedDecl *D);
NamedDecl *getAcceptableDeclSlow(NamedDecl *D) const;
public:
/// Returns the identifier namespace mask for this lookup.
unsigned getIdentifierNamespace() const {
return IDNS;
}
/// Returns whether these results arose from performing a
/// lookup into a class.
bool isClassLookup() const {
return NamingClass != nullptr;
}
/// Returns the 'naming class' for this lookup, i.e. the
/// class which was looked into to find these results.
///
/// C++0x [class.access.base]p5:
/// The access to a member is affected by the class in which the
/// member is named. This naming class is the class in which the
/// member name was looked up and found. [Note: this class can be
/// explicit, e.g., when a qualified-id is used, or implicit,
/// e.g., when a class member access operator (5.2.5) is used
/// (including cases where an implicit "this->" is added). If both
/// a class member access operator and a qualified-id are used to
/// name the member (as in p->T::m), the class naming the member
/// is the class named by the nested-name-specifier of the
/// qualified-id (that is, T). -- end note ]
///
/// This is set by the lookup routines when they find results in a class.
CXXRecordDecl *getNamingClass() const {
return NamingClass;
}
/// Sets the 'naming class' for this lookup.
void setNamingClass(CXXRecordDecl *Record) {
NamingClass = Record;
}
/// Returns the base object type associated with this lookup;
/// important for [class.protected]. Most lookups do not have an
/// associated base object.
QualType getBaseObjectType() const {
return BaseObjectType;
}
/// Sets the base object type for this lookup.
void setBaseObjectType(QualType T) {
BaseObjectType = T;
}
/// Add a declaration to these results with its natural access.
/// Does not test the acceptance criteria.
void addDecl(NamedDecl *D) {
addDecl(D, D->getAccess());
}
/// Add a declaration to these results with the given access.
/// Does not test the acceptance criteria.
void addDecl(NamedDecl *D, AccessSpecifier AS) {
Decls.addDecl(D, AS);
ResultKind = Found;
}
/// Add all the declarations from another set of lookup
/// results.
void addAllDecls(const LookupResult &Other) {
Decls.append(Other.Decls.begin(), Other.Decls.end());
ResultKind = Found;
}
/// Determine whether no result was found because we could not
/// search into dependent base classes of the current instantiation.
bool wasNotFoundInCurrentInstantiation() const {
return ResultKind == NotFoundInCurrentInstantiation;
}
/// Note that while no result was found in the current instantiation,
/// there were dependent base classes that could not be searched.
void setNotFoundInCurrentInstantiation() {
assert((ResultKind == NotFound ||
ResultKind == NotFoundInCurrentInstantiation) &&
Decls.empty());
ResultKind = NotFoundInCurrentInstantiation;
}
/// Determine whether the lookup result was shadowed by some other
/// declaration that lookup ignored.
bool isShadowed() const { return Shadowed; }
/// Note that we found and ignored a declaration while performing
/// lookup.
void setShadowed() { Shadowed = true; }
/// Resolves the result kind of the lookup, possibly hiding
/// decls.
///
/// This should be called in any environment where lookup might
/// generate multiple lookup results.
void resolveKind();
/// Re-resolves the result kind of the lookup after a set of
/// removals has been performed.
void resolveKindAfterFilter() {
if (Decls.empty()) {
if (ResultKind != NotFoundInCurrentInstantiation)
ResultKind = NotFound;
if (Paths) {
deletePaths(Paths);
Paths = nullptr;
}
} else {
std::optional<AmbiguityKind> SavedAK;
bool WasAmbiguous = false;
if (ResultKind == Ambiguous) {
SavedAK = Ambiguity;
WasAmbiguous = true;
}
ResultKind = Found;
resolveKind();
// If we didn't make the lookup unambiguous, restore the old
// ambiguity kind.
if (ResultKind == Ambiguous) {
(void)WasAmbiguous;
assert(WasAmbiguous);
Ambiguity = *SavedAK;
} else if (Paths) {
deletePaths(Paths);
Paths = nullptr;
}
}
}
template <class DeclClass>
DeclClass *getAsSingle() const {
if (getResultKind() != Found) return nullptr;
return dyn_cast<DeclClass>(getFoundDecl());
}
/// Fetch the unique decl found by this lookup. Asserts
/// that one was found.
///
/// This is intended for users who have examined the result kind
/// and are certain that there is only one result.
NamedDecl *getFoundDecl() const {
assert(getResultKind() == Found
&& "getFoundDecl called on non-unique result");
return (*begin())->getUnderlyingDecl();
}
/// Fetches a representative decl. Useful for lazy diagnostics.
NamedDecl *getRepresentativeDecl() const {
assert(!Decls.empty() && "cannot get representative of empty set");
return *begin();
}
/// Asks if the result is a single tag decl.
bool isSingleTagDecl() const {
return getResultKind() == Found && isa<TagDecl>(getFoundDecl());
}
/// Make these results show that the name was found in
/// base classes of different types.
///
/// The given paths object is copied and invalidated.
void setAmbiguousBaseSubobjectTypes(CXXBasePaths &P);
/// Make these results show that the name was found in
/// distinct base classes of the same type.
///
/// The given paths object is copied and invalidated.
void setAmbiguousBaseSubobjects(CXXBasePaths &P);
/// Make these results show that the name was found in
/// different contexts and a tag decl was hidden by an ordinary
/// decl in a different context.
void setAmbiguousQualifiedTagHiding() {
setAmbiguous(AmbiguousTagHiding);
}
/// Clears out any current state.
LLVM_ATTRIBUTE_REINITIALIZES void clear() {
ResultKind = NotFound;
Decls.clear();
if (Paths) deletePaths(Paths);
Paths = nullptr;
NamingClass = nullptr;
Shadowed = false;
}
/// Clears out any current state and re-initializes for a
/// different kind of lookup.
void clear(Sema::LookupNameKind Kind) {
clear();
LookupKind = Kind;
configure();
}
/// Change this lookup's redeclaration kind.
void setRedeclarationKind(RedeclarationKind RK) {
Redecl = (RK != RedeclarationKind::NotForRedeclaration);
ExternalRedecl = (RK == RedeclarationKind::ForExternalRedeclaration);
configure();
}
void dump();
void print(raw_ostream &);
/// Suppress the diagnostics that would normally fire because of this
/// lookup. This happens during (e.g.) redeclaration lookups.
void suppressDiagnostics() {
DiagnoseAccess = false;
DiagnoseAmbiguous = false;
}
/// Suppress the diagnostics that would normally fire because of this
/// lookup due to access control violations.
void suppressAccessDiagnostics() { DiagnoseAccess = false; }
/// Determines whether this lookup is suppressing access control diagnostics.
bool isSuppressingAccessDiagnostics() const { return !DiagnoseAccess; }
/// Determines whether this lookup is suppressing ambiguous lookup
/// diagnostics.
bool isSuppressingAmbiguousDiagnostics() const { return !DiagnoseAmbiguous; }
/// Sets a 'context' source range.
void setContextRange(SourceRange SR) {
NameContextRange = SR;
}
/// Gets the source range of the context of this name; for C++
/// qualified lookups, this is the source range of the scope
/// specifier.
SourceRange getContextRange() const {
return NameContextRange;
}
/// Gets the location of the identifier. This isn't always defined:
/// sometimes we're doing lookups on synthesized names.
SourceLocation getNameLoc() const {
return NameInfo.getLoc();
}
/// Get the Sema object that this lookup result is searching
/// with.
Sema &getSema() const { return *SemaPtr; }
/// A class for iterating through a result set and possibly
/// filtering out results. The results returned are possibly
/// sugared.
class Filter {
friend class LookupResult;
LookupResult &Results;
LookupResult::iterator I;
bool Changed = false;
bool CalledDone = false;
Filter(LookupResult &Results) : Results(Results), I(Results.begin()) {}
public:
Filter(Filter &&F)
: Results(F.Results), I(F.I), Changed(F.Changed),
CalledDone(F.CalledDone) {
F.CalledDone = true;
}
// The move assignment operator is defined as deleted pending
// further motivation.
Filter &operator=(Filter &&) = delete;
// The copy constrcutor and copy assignment operator is defined as deleted
// pending further motivation.
Filter(const Filter &) = delete;
Filter &operator=(const Filter &) = delete;
~Filter() {
assert(CalledDone &&
"LookupResult::Filter destroyed without done() call");
}
bool hasNext() const {
return I != Results.end();
}
NamedDecl *next() {
assert(I != Results.end() && "next() called on empty filter");
return *I++;
}
/// Restart the iteration.
void restart() {
I = Results.begin();
}
/// Erase the last element returned from this iterator.
void erase() {
Results.Decls.erase(--I);
Changed = true;
}
/// Replaces the current entry with the given one, preserving the
/// access bits.
void replace(NamedDecl *D) {
Results.Decls.replace(I-1, D);
Changed = true;
}
/// Replaces the current entry with the given one.
void replace(NamedDecl *D, AccessSpecifier AS) {
Results.Decls.replace(I-1, D, AS);
Changed = true;
}
void done() {
assert(!CalledDone && "done() called twice");
CalledDone = true;
if (Changed)
Results.resolveKindAfterFilter();
}
};
/// Create a filter for this result set.
Filter makeFilter() {
return Filter(*this);
}
void setFindLocalExtern(bool FindLocalExtern) {
if (FindLocalExtern)
IDNS |= Decl::IDNS_LocalExtern;
else
IDNS &= ~Decl::IDNS_LocalExtern;
}
private:
void diagnoseAccess() {
if (!isAmbiguous() && isClassLookup() &&
getSema().getLangOpts().AccessControl)
getSema().CheckLookupAccess(*this);
}
void diagnoseAmbiguous() {
if (isAmbiguous())
getSema().DiagnoseAmbiguousLookup(*this);
}
void setAmbiguous(AmbiguityKind AK) {
ResultKind = Ambiguous;
Ambiguity = AK;
}
void addDeclsFromBasePaths(const CXXBasePaths &P);
void configure();
bool checkDebugAssumptions() const;
bool checkUnresolved() const {
for (iterator I = begin(), E = end(); I != E; ++I)
if (isa<UnresolvedUsingValueDecl>((*I)->getUnderlyingDecl()))
return true;
return false;
}
static void deletePaths(CXXBasePaths *);
// Results.
LookupResultKind ResultKind = NotFound;
// ill-defined unless ambiguous. Still need to be initialized it will be
// copied/moved.
AmbiguityKind Ambiguity = {};
UnresolvedSet<8> Decls;
CXXBasePaths *Paths = nullptr;
CXXRecordDecl *NamingClass = nullptr;
QualType BaseObjectType;
// Parameters.
Sema *SemaPtr;
DeclarationNameInfo NameInfo;
SourceRange NameContextRange;
Sema::LookupNameKind LookupKind;
unsigned IDNS = 0; // set by configure()
bool Redecl;
bool ExternalRedecl;
/// True if tag declarations should be hidden if non-tags
/// are present
bool HideTags = true;
bool DiagnoseAccess = false;
bool DiagnoseAmbiguous = false;
/// True if we should allow hidden declarations to be 'visible'.
bool AllowHidden = false;
/// True if the found declarations were shadowed by some other
/// declaration that we skipped. This only happens when \c LookupKind
/// is \c LookupRedeclarationWithLinkage.
bool Shadowed = false;
/// True if we're looking up a template-name.
bool TemplateNameLookup = false;
};
/// Consumes visible declarations found when searching for
/// all visible names within a given scope or context.
///
/// This abstract class is meant to be subclassed by clients of \c
/// Sema::LookupVisibleDecls(), each of which should override the \c
/// FoundDecl() function to process declarations as they are found.
class VisibleDeclConsumer {
public:
/// Destroys the visible declaration consumer.
virtual ~VisibleDeclConsumer();
/// Determine whether hidden declarations (from unimported
/// modules) should be given to this consumer. By default, they
/// are not included.
virtual bool includeHiddenDecls() const;
/// Invoked each time \p Sema::LookupVisibleDecls() finds a
/// declaration visible from the current scope or context.
///
/// \param ND the declaration found.
///
/// \param Hiding a declaration that hides the declaration \p ND,
/// or NULL if no such declaration exists.
///
/// \param Ctx the original context from which the lookup started.
///
/// \param InBaseClass whether this declaration was found in base
/// class of the context we searched.
virtual void FoundDecl(NamedDecl *ND, NamedDecl *Hiding, DeclContext *Ctx,
bool InBaseClass) = 0;
/// Callback to inform the client that Sema entered into a new context
/// to find a visible declaration.
//
/// \param Ctx the context which Sema entered.
virtual void EnteredContext(DeclContext *Ctx) {}
};
/// A class for storing results from argument-dependent lookup.
class ADLResult {
private:
/// A map from canonical decls to the 'most recent' decl.
llvm::MapVector<NamedDecl*, NamedDecl*> Decls;
struct select_second {
NamedDecl *operator()(std::pair<NamedDecl*, NamedDecl*> P) const {
return P.second;
}
};
public:
/// Adds a new ADL candidate to this map.
void insert(NamedDecl *D);
/// Removes any data associated with a given decl.
void erase(NamedDecl *D) {
Decls.erase(cast<NamedDecl>(D->getCanonicalDecl()));
}
using iterator =
llvm::mapped_iterator<decltype(Decls)::iterator, select_second>;
iterator begin() { return iterator(Decls.begin(), select_second()); }
iterator end() { return iterator(Decls.end(), select_second()); }
};
} // namespace clang
#endif // LLVM_CLANG_SEMA_LOOKUP_H
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