532 lines
15 KiB
C++
532 lines
15 KiB
C++
//===--- Lookup.h - Classes for name lookup ---------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the LookupResult class, which is integral to
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// Sema's name-lookup subsystem.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_SEMA_LOOKUP_H
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#define LLVM_CLANG_SEMA_LOOKUP_H
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#include "Sema.h"
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namespace clang {
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/// @brief Represents the results of name lookup.
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///
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/// An instance of the LookupResult class captures the results of a
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/// single name lookup, which can return no result (nothing found),
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/// a single declaration, a set of overloaded functions, or an
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/// ambiguity. Use the getKind() method to determine which of these
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/// results occurred for a given lookup.
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class LookupResult {
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public:
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enum LookupResultKind {
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/// @brief No entity found met the criteria.
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NotFound = 0,
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/// @brief Name lookup found a single declaration that met the
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/// criteria. getFoundDecl() will return this declaration.
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Found,
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/// @brief Name lookup found a set of overloaded functions that
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/// met the criteria.
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FoundOverloaded,
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/// @brief Name lookup found an unresolvable value declaration
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/// and cannot yet complete. This only happens in C++ dependent
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/// contexts with dependent using declarations.
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FoundUnresolvedValue,
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/// @brief Name lookup results in an ambiguity; use
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/// getAmbiguityKind to figure out what kind of ambiguity
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/// we have.
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Ambiguous
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};
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enum AmbiguityKind {
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/// Name lookup results in an ambiguity because multiple
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/// entities that meet the lookup criteria were found in
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/// subobjects of different types. For example:
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/// @code
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/// struct A { void f(int); }
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/// struct B { void f(double); }
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/// struct C : A, B { };
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/// void test(C c) {
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/// c.f(0); // error: A::f and B::f come from subobjects of different
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/// // types. overload resolution is not performed.
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/// }
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/// @endcode
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AmbiguousBaseSubobjectTypes,
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/// Name lookup results in an ambiguity because multiple
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/// nonstatic entities that meet the lookup criteria were found
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/// in different subobjects of the same type. For example:
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/// @code
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/// struct A { int x; };
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/// struct B : A { };
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/// struct C : A { };
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/// struct D : B, C { };
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/// int test(D d) {
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/// return d.x; // error: 'x' is found in two A subobjects (of B and C)
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/// }
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/// @endcode
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AmbiguousBaseSubobjects,
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/// Name lookup results in an ambiguity because multiple definitions
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/// of entity that meet the lookup criteria were found in different
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/// declaration contexts.
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/// @code
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/// namespace A {
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/// int i;
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/// namespace B { int i; }
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/// int test() {
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/// using namespace B;
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/// return i; // error 'i' is found in namespace A and A::B
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/// }
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/// }
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/// @endcode
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AmbiguousReference,
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/// Name lookup results in an ambiguity because an entity with a
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/// tag name was hidden by an entity with an ordinary name from
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/// a different context.
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/// @code
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/// namespace A { struct Foo {}; }
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/// namespace B { void Foo(); }
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/// namespace C {
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/// using namespace A;
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/// using namespace B;
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/// }
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/// void test() {
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/// C::Foo(); // error: tag 'A::Foo' is hidden by an object in a
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/// // different namespace
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/// }
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/// @endcode
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AmbiguousTagHiding
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};
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/// A little identifier for flagging temporary lookup results.
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enum TemporaryToken {
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Temporary
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};
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typedef llvm::SmallVector<NamedDecl*, 4> DeclsTy;
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typedef DeclsTy::const_iterator iterator;
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typedef bool (*ResultFilter)(NamedDecl*, unsigned IDNS);
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LookupResult(Sema &SemaRef, DeclarationName Name, SourceLocation NameLoc,
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Sema::LookupNameKind LookupKind,
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Sema::RedeclarationKind Redecl = Sema::NotForRedeclaration)
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: ResultKind(NotFound),
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Paths(0),
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SemaRef(SemaRef),
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Name(Name),
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NameLoc(NameLoc),
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LookupKind(LookupKind),
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IsAcceptableFn(0),
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IDNS(0),
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Redecl(Redecl != Sema::NotForRedeclaration),
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HideTags(true),
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Diagnose(Redecl == Sema::NotForRedeclaration)
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{
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configure();
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}
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/// Creates a temporary lookup result, initializing its core data
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/// using the information from another result. Diagnostics are always
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/// disabled.
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LookupResult(TemporaryToken _, const LookupResult &Other)
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: ResultKind(NotFound),
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Paths(0),
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SemaRef(Other.SemaRef),
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Name(Other.Name),
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NameLoc(Other.NameLoc),
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LookupKind(Other.LookupKind),
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IsAcceptableFn(Other.IsAcceptableFn),
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IDNS(Other.IDNS),
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Redecl(Other.Redecl),
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HideTags(Other.HideTags),
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Diagnose(false)
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{}
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~LookupResult() {
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if (Diagnose) diagnose();
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if (Paths) deletePaths(Paths);
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}
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/// Gets the name to look up.
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DeclarationName getLookupName() const {
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return Name;
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}
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/// \brief Sets the name to look up.
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void setLookupName(DeclarationName Name) {
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this->Name = Name;
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}
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/// Gets the kind of lookup to perform.
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Sema::LookupNameKind getLookupKind() const {
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return LookupKind;
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}
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/// True if this lookup is just looking for an existing declaration.
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bool isForRedeclaration() const {
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return Redecl;
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}
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/// Sets whether tag declarations should be hidden by non-tag
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/// declarations during resolution. The default is true.
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void setHideTags(bool Hide) {
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HideTags = Hide;
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}
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bool isAmbiguous() const {
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return getResultKind() == Ambiguous;
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}
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/// Determines if this names a single result which is not an
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/// unresolved value using decl. If so, it is safe to call
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/// getFoundDecl().
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bool isSingleResult() const {
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return getResultKind() == Found;
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}
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/// Determines if the results are overloaded.
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bool isOverloadedResult() const {
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return getResultKind() == FoundOverloaded;
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}
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bool isUnresolvableResult() const {
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return getResultKind() == FoundUnresolvedValue;
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}
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LookupResultKind getResultKind() const {
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sanity();
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return ResultKind;
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}
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AmbiguityKind getAmbiguityKind() const {
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assert(isAmbiguous());
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return Ambiguity;
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}
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iterator begin() const { return Decls.begin(); }
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iterator end() const { return Decls.end(); }
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/// \brief Return true if no decls were found
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bool empty() const { return Decls.empty(); }
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/// \brief Return the base paths structure that's associated with
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/// these results, or null if none is.
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CXXBasePaths *getBasePaths() const {
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return Paths;
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}
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/// \brief Tests whether the given declaration is acceptable.
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bool isAcceptableDecl(NamedDecl *D) const {
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assert(IsAcceptableFn);
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return IsAcceptableFn(D, IDNS);
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}
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/// \brief Returns the identifier namespace mask for this lookup.
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unsigned getIdentifierNamespace() const {
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return IDNS;
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}
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/// \brief Add a declaration to these results. Does not test the
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/// acceptance criteria.
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void addDecl(NamedDecl *D) {
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Decls.push_back(D);
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ResultKind = Found;
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}
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/// \brief Add all the declarations from another set of lookup
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/// results.
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void addAllDecls(const LookupResult &Other) {
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Decls.append(Other.begin(), Other.end());
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ResultKind = Found;
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}
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/// \brief Hides a set of declarations.
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template <class NamedDeclSet> void hideDecls(const NamedDeclSet &Set) {
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unsigned I = 0, N = Decls.size();
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while (I < N) {
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if (Set.count(Decls[I]))
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Decls[I] = Decls[--N];
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else
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I++;
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}
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Decls.set_size(N);
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}
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/// \brief Resolves the result kind of the lookup, possibly hiding
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/// decls.
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///
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/// This should be called in any environment where lookup might
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/// generate multiple lookup results.
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void resolveKind();
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/// \brief Re-resolves the result kind of the lookup after a set of
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/// removals has been performed.
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void resolveKindAfterFilter() {
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if (Decls.empty())
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ResultKind = NotFound;
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else {
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ResultKind = Found;
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resolveKind();
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}
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}
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template <class DeclClass>
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DeclClass *getAsSingle() const {
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if (getResultKind() != Found) return 0;
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return dyn_cast<DeclClass>(getFoundDecl());
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}
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/// \brief Fetch the unique decl found by this lookup. Asserts
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/// that one was found.
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///
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/// This is intended for users who have examined the result kind
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/// and are certain that there is only one result.
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NamedDecl *getFoundDecl() const {
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assert(getResultKind() == Found
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&& "getFoundDecl called on non-unique result");
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return Decls[0]->getUnderlyingDecl();
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}
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/// Fetches a representative decl. Useful for lazy diagnostics.
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NamedDecl *getRepresentativeDecl() const {
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assert(!Decls.empty() && "cannot get representative of empty set");
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return Decls[0];
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}
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/// \brief Asks if the result is a single tag decl.
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bool isSingleTagDecl() const {
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return getResultKind() == Found && isa<TagDecl>(getFoundDecl());
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}
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/// \brief Make these results show that the name was found in
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/// base classes of different types.
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///
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/// The given paths object is copied and invalidated.
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void setAmbiguousBaseSubobjectTypes(CXXBasePaths &P);
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/// \brief Make these results show that the name was found in
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/// distinct base classes of the same type.
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///
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/// The given paths object is copied and invalidated.
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void setAmbiguousBaseSubobjects(CXXBasePaths &P);
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/// \brief Make these results show that the name was found in
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/// different contexts and a tag decl was hidden by an ordinary
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/// decl in a different context.
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void setAmbiguousQualifiedTagHiding() {
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setAmbiguous(AmbiguousTagHiding);
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}
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/// \brief Clears out any current state.
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void clear() {
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ResultKind = NotFound;
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Decls.clear();
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if (Paths) deletePaths(Paths);
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Paths = NULL;
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}
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/// \brief Clears out any current state and re-initializes for a
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/// different kind of lookup.
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void clear(Sema::LookupNameKind Kind) {
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clear();
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LookupKind = Kind;
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configure();
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}
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void print(llvm::raw_ostream &);
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/// Suppress the diagnostics that would normally fire because of this
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/// lookup. This happens during (e.g.) redeclaration lookups.
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void suppressDiagnostics() {
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Diagnose = false;
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}
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/// Sets a 'context' source range.
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void setContextRange(SourceRange SR) {
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NameContextRange = SR;
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}
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/// Gets the source range of the context of this name; for C++
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/// qualified lookups, this is the source range of the scope
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/// specifier.
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SourceRange getContextRange() const {
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return NameContextRange;
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}
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/// Gets the location of the identifier. This isn't always defined:
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/// sometimes we're doing lookups on synthesized names.
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SourceLocation getNameLoc() const {
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return NameLoc;
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}
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/// \brief Get the Sema object that this lookup result is searching
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/// with.
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Sema &getSema() const { return SemaRef; }
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/// A class for iterating through a result set and possibly
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/// filtering out results. The results returned are possibly
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/// sugared.
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class Filter {
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LookupResult &Results;
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unsigned I;
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bool Changed;
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#ifndef NDEBUG
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bool CalledDone;
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#endif
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friend class LookupResult;
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Filter(LookupResult &Results)
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: Results(Results), I(0), Changed(false)
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#ifndef NDEBUG
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, CalledDone(false)
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#endif
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{}
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public:
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#ifndef NDEBUG
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~Filter() {
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assert(CalledDone &&
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"LookupResult::Filter destroyed without done() call");
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}
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#endif
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bool hasNext() const {
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return I != Results.Decls.size();
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}
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NamedDecl *next() {
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assert(I < Results.Decls.size() && "next() called on empty filter");
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return Results.Decls[I++];
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}
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/// Erase the last element returned from this iterator.
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void erase() {
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Results.Decls[--I] = Results.Decls.back();
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Results.Decls.pop_back();
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Changed = true;
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}
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void replace(NamedDecl *D) {
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Results.Decls[I-1] = D;
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Changed = true;
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}
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void done() {
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#ifndef NDEBUG
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assert(!CalledDone && "done() called twice");
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CalledDone = true;
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#endif
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if (Changed)
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Results.resolveKindAfterFilter();
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}
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};
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/// Create a filter for this result set.
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Filter makeFilter() {
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return Filter(*this);
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}
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private:
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void diagnose() {
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if (isAmbiguous())
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SemaRef.DiagnoseAmbiguousLookup(*this);
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}
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void setAmbiguous(AmbiguityKind AK) {
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ResultKind = Ambiguous;
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Ambiguity = AK;
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}
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void addDeclsFromBasePaths(const CXXBasePaths &P);
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void configure();
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// Sanity checks.
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void sanity() const {
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assert(ResultKind != NotFound || Decls.size() == 0);
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assert(ResultKind != Found || Decls.size() == 1);
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assert(ResultKind != FoundOverloaded || Decls.size() > 1 ||
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(Decls.size() == 1 &&
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isa<FunctionTemplateDecl>(Decls[0]->getUnderlyingDecl())));
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assert(ResultKind != FoundUnresolvedValue || sanityCheckUnresolved());
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assert(ResultKind != Ambiguous || Decls.size() > 1 ||
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(Decls.size() == 1 && Ambiguity == AmbiguousBaseSubobjects));
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assert((Paths != NULL) == (ResultKind == Ambiguous &&
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(Ambiguity == AmbiguousBaseSubobjectTypes ||
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Ambiguity == AmbiguousBaseSubobjects)));
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}
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bool sanityCheckUnresolved() const {
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for (DeclsTy::const_iterator I = Decls.begin(), E = Decls.end();
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I != E; ++I)
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if (isa<UnresolvedUsingValueDecl>(*I))
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return true;
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return false;
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}
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static void deletePaths(CXXBasePaths *);
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// Results.
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LookupResultKind ResultKind;
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AmbiguityKind Ambiguity; // ill-defined unless ambiguous
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DeclsTy Decls;
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CXXBasePaths *Paths;
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// Parameters.
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Sema &SemaRef;
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DeclarationName Name;
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SourceLocation NameLoc;
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SourceRange NameContextRange;
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Sema::LookupNameKind LookupKind;
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ResultFilter IsAcceptableFn; // set by configure()
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unsigned IDNS; // set by configure()
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bool Redecl;
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/// \brief True if tag declarations should be hidden if non-tags
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/// are present
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bool HideTags;
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bool Diagnose;
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};
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/// \brief Consumes visible declarations found when searching for
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/// all visible names within a given scope or context.
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///
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/// This abstract class is meant to be subclassed by clients of \c
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/// Sema::LookupVisibleDecls(), each of which should override the \c
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/// FoundDecl() function to process declarations as they are found.
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class VisibleDeclConsumer {
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public:
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/// \brief Destroys the visible declaration consumer.
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virtual ~VisibleDeclConsumer();
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/// \brief Invoked each time \p Sema::LookupVisibleDecls() finds a
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/// declaration visible from the current scope or context.
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///
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/// \param ND the declaration found.
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///
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/// \param Hiding a declaration that hides the declaration \p ND,
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/// or NULL if no such declaration exists.
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virtual void FoundDecl(NamedDecl *ND, NamedDecl *Hiding) = 0;
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};
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}
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#endif
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