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//===--- Lookup.h - Classes for name lookup ---------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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 "Sema.h"
namespace clang {
/// @brief 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.
///
/// Any non-ambiguous lookup can be converted into a single
/// (possibly NULL) @c NamedDecl* via the getAsSingleDecl() method.
/// This permits the common-case usage in C and Objective-C where
/// name lookup will always return a single declaration. Use of
/// this is largely deprecated; callers should handle the possibility
/// of multiple declarations.
class LookupResult {
public:
enum LookupResultKind {
/// @brief No entity found met the criteria.
NotFound = 0,
/// @brief Name lookup found a single declaration that met the
/// criteria. getAsDecl will return this declaration.
Found,
/// @brief Name lookup found a set of overloaded functions that
/// met the criteria. getAsDecl will turn this set of overloaded
/// functions into an OverloadedFunctionDecl.
FoundOverloaded,
/// @brief Name lookup found an unresolvable value declaration
/// and cannot yet complete. This only happens in C++ dependent
/// contexts with dependent using declarations.
FoundUnresolvedValue,
/// @brief 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 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
};
typedef llvm::SmallVector<NamedDecl*, 4> DeclsTy;
typedef DeclsTy::const_iterator iterator;
LookupResult(Sema &SemaRef, DeclarationName Name, SourceLocation NameLoc,
Sema::LookupNameKind LookupKind,
Sema::RedeclarationKind Redecl = Sema::NotForRedeclaration)
: ResultKind(NotFound),
Paths(0),
SemaRef(SemaRef),
Name(Name),
NameLoc(NameLoc),
LookupKind(LookupKind),
IDNS(0),
Redecl(Redecl != Sema::NotForRedeclaration),
HideTags(true),
Diagnose(Redecl == Sema::NotForRedeclaration)
{}
/// Creates a temporary lookup result, initializing its core data
/// using the information from another result. Diagnostics are always
/// disabled.
LookupResult(TemporaryToken _, const LookupResult &Other)
: ResultKind(NotFound),
Paths(0),
SemaRef(Other.SemaRef),
Name(Other.Name),
NameLoc(Other.NameLoc),
LookupKind(Other.LookupKind),
IDNS(Other.IDNS),
Redecl(Other.Redecl),
HideTags(Other.HideTags),
Diagnose(false)
{}
~LookupResult() {
if (Diagnose) diagnose();
if (Paths) deletePaths(Paths);
}
/// Gets the name to look up.
DeclarationName getLookupName() const {
return 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;
}
/// Sets whether tag declarations should be hidden by non-tag
/// declarations during resolution. The default is true.
void setHideTags(bool Hide) {
HideTags = Hide;
}
/// The identifier namespace of this lookup. This information is
/// private to the lookup routines.
unsigned getIdentifierNamespace() const {
assert(IDNS);
return IDNS;
}
void setIdentifierNamespace(unsigned NS) {
IDNS = NS;
}
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;
}
LookupResultKind getResultKind() const {
sanity();
return ResultKind;
}
AmbiguityKind getAmbiguityKind() const {
assert(isAmbiguous());
return Ambiguity;
}
iterator begin() const { return Decls.begin(); }
iterator end() const { return Decls.end(); }
/// \brief Return true if no decls were found
bool empty() const { return Decls.empty(); }
/// \brief Return the base paths structure that's associated with
/// these results, or null if none is.
CXXBasePaths *getBasePaths() const {
return Paths;
}
/// \brief Add a declaration to these results.
void addDecl(NamedDecl *D) {
Decls.push_back(D);
ResultKind = Found;
}
/// \brief Add all the declarations from another set of lookup
/// results.
void addAllDecls(const LookupResult &Other) {
Decls.append(Other.begin(), Other.end());
ResultKind = Found;
}
/// \brief Hides a set of declarations.
template <class NamedDeclSet> void hideDecls(const NamedDeclSet &Set) {
unsigned I = 0, N = Decls.size();
while (I < N) {
if (Set.count(Decls[I]))
Decls[I] = Decls[--N];
else
I++;
}
Decls.set_size(N);
}
/// \brief 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();
/// \brief Re-resolves the result kind of the lookup after a set of
/// removals has been performed.
void resolveKindAfterFilter() {
if (Decls.empty())
ResultKind = NotFound;
else {
ResultKind = Found;
resolveKind();
}
}
/// \brief Fetch this as an unambiguous single declaration
/// (possibly an overloaded one).
///
/// This is deprecated; users should be written to handle
/// ambiguous and overloaded lookups.
NamedDecl *getAsSingleDecl(ASTContext &Context) const;
template <class DeclClass>
DeclClass *getAsSingle() const {
if (getResultKind() != Found) return 0;
return dyn_cast<DeclClass>(getFoundDecl());
}
/// \brief 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 Decls[0]->getUnderlyingDecl();
}
/// Fetches a representative decl. Useful for lazy diagnostics.
NamedDecl *getRepresentativeDecl() const {
assert(!Decls.empty() && "cannot get representative of empty set");
return Decls[0];
}
/// \brief Asks if the result is a single tag decl.
bool isSingleTagDecl() const {
return getResultKind() == Found && isa<TagDecl>(getFoundDecl());
}
/// \brief 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);
/// \brief 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);
/// \brief 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);
}
/// \brief Clears out any current state.
void clear() {
ResultKind = NotFound;
Decls.clear();
if (Paths) deletePaths(Paths);
Paths = NULL;
}
/// \brief Clears out any current state and re-initializes for a
/// different kind of lookup.
void clear(Sema::LookupNameKind Kind) {
clear();
LookupKind = Kind;
}
void print(llvm::raw_ostream &);
/// Suppress the diagnostics that would normally fire because of this
/// lookup. This happens during (e.g.) redeclaration lookups.
void suppressDiagnostics() {
Diagnose = false;
}
/// 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 NameLoc;
}
/// A class for iterating through a result set and possibly
/// filtering out results. The results returned are possibly
/// sugared.
class Filter {
LookupResult &Results;
unsigned I;
bool Changed;
#ifndef NDEBUG
bool CalledDone;
#endif
friend class LookupResult;
Filter(LookupResult &Results)
: Results(Results), I(0), Changed(false)
#ifndef NDEBUG
, CalledDone(false)
#endif
{}
public:
#ifndef NDEBUG
~Filter() {
assert(CalledDone &&
"LookupResult::Filter destroyed without done() call");
}
#endif
bool hasNext() const {
return I != Results.Decls.size();
}
NamedDecl *next() {
assert(I < Results.Decls.size() && "next() called on empty filter");
return Results.Decls[I++];
}
/// Erase the last element returned from this iterator.
void erase() {
Results.Decls[--I] = Results.Decls.back();
Results.Decls.pop_back();
Changed = true;
}
void replace(NamedDecl *D) {
Results.Decls[I-1] = D;
Changed = true;
}
void done() {
#ifndef NDEBUG
assert(!CalledDone && "done() called twice");
CalledDone = true;
#endif
if (Changed)
Results.resolveKindAfterFilter();
}
};
/// Create a filter for this result set.
Filter makeFilter() {
return Filter(*this);
}
private:
void diagnose() {
if (isAmbiguous())
SemaRef.DiagnoseAmbiguousLookup(*this);
}
void setAmbiguous(AmbiguityKind AK) {
ResultKind = Ambiguous;
Ambiguity = AK;
}
void addDeclsFromBasePaths(const CXXBasePaths &P);
// Sanity checks.
void sanity() const {
assert(ResultKind != NotFound || Decls.size() == 0);
assert(ResultKind != Found || Decls.size() == 1);
assert(ResultKind != FoundOverloaded || Decls.size() > 1 ||
(Decls.size() == 1 &&
isa<FunctionTemplateDecl>(Decls[0]->getUnderlyingDecl())));
assert(ResultKind != FoundUnresolvedValue || sanityCheckUnresolved());
assert(ResultKind != Ambiguous || Decls.size() > 1 ||
(Decls.size() == 1 && Ambiguity == AmbiguousBaseSubobjects));
assert((Paths != NULL) == (ResultKind == Ambiguous &&
(Ambiguity == AmbiguousBaseSubobjectTypes ||
Ambiguity == AmbiguousBaseSubobjects)));
}
bool sanityCheckUnresolved() const {
for (DeclsTy::const_iterator I = Decls.begin(), E = Decls.end();
I != E; ++I)
if (isa<UnresolvedUsingValueDecl>(*I))
return true;
return false;
}
static void deletePaths(CXXBasePaths *);
// Results.
LookupResultKind ResultKind;
AmbiguityKind Ambiguity; // ill-defined unless ambiguous
DeclsTy Decls;
CXXBasePaths *Paths;
// Parameters.
Sema &SemaRef;
DeclarationName Name;
SourceLocation NameLoc;
SourceRange NameContextRange;
Sema::LookupNameKind LookupKind;
unsigned IDNS; // ill-defined until set by lookup
bool Redecl;
/// \brief True if tag declarations should be hidden if non-tags
/// are present
bool HideTags;
bool Diagnose;
};
}
#endif