278 lines
9.3 KiB
C++
278 lines
9.3 KiB
C++
//===-- Redeclarable.h - Base for Decls that can be redeclared -*- 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 Redeclarable interface.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_AST_REDECLARABLE_H
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#define LLVM_CLANG_AST_REDECLARABLE_H
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#include "clang/AST/ExternalASTSource.h"
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#include "llvm/ADT/PointerIntPair.h"
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#include "llvm/Support/Casting.h"
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#include <iterator>
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namespace clang {
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/// \brief Provides common interface for the Decls that can be redeclared.
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template<typename decl_type>
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class Redeclarable {
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protected:
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class DeclLink {
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/// A pointer to a known latest declaration, either statically known or
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/// generationally updated as decls are added by an external source.
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typedef LazyGenerationalUpdatePtr<const Decl*, Decl*,
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&ExternalASTSource::CompleteRedeclChain>
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KnownLatest;
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typedef const ASTContext *UninitializedLatest;
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typedef Decl *Previous;
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/// A pointer to either an uninitialized latest declaration (where either
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/// we've not yet set the previous decl or there isn't one), or to a known
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/// previous declaration.
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typedef llvm::PointerUnion<Previous, UninitializedLatest> NotKnownLatest;
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mutable llvm::PointerUnion<NotKnownLatest, KnownLatest> Next;
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public:
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enum PreviousTag { PreviousLink };
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enum LatestTag { LatestLink };
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DeclLink(LatestTag, const ASTContext &Ctx)
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: Next(NotKnownLatest(&Ctx)) {}
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DeclLink(PreviousTag, decl_type *D)
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: Next(NotKnownLatest(Previous(D))) {}
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bool NextIsPrevious() const {
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return Next.is<NotKnownLatest>() &&
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// FIXME: 'template' is required on the next line due to an
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// apparent clang bug.
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Next.get<NotKnownLatest>().template is<Previous>();
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}
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bool NextIsLatest() const { return !NextIsPrevious(); }
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decl_type *getNext(const decl_type *D) const {
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if (Next.is<NotKnownLatest>()) {
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NotKnownLatest NKL = Next.get<NotKnownLatest>();
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if (NKL.is<Previous>())
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return static_cast<decl_type*>(NKL.get<Previous>());
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// Allocate the generational 'most recent' cache now, if needed.
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Next = KnownLatest(*NKL.get<UninitializedLatest>(),
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const_cast<decl_type *>(D));
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}
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return static_cast<decl_type*>(Next.get<KnownLatest>().get(D));
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}
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void setPrevious(decl_type *D) {
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assert(NextIsPrevious() && "decl became non-canonical unexpectedly");
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Next = Previous(D);
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}
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void setLatest(decl_type *D) {
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assert(NextIsLatest() && "decl became canonical unexpectedly");
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if (Next.is<NotKnownLatest>()) {
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NotKnownLatest NKL = Next.get<NotKnownLatest>();
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Next = KnownLatest(*NKL.get<UninitializedLatest>(), D);
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} else {
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auto Latest = Next.get<KnownLatest>();
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Latest.set(D);
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Next = Latest;
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}
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}
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void markIncomplete() { Next.get<KnownLatest>().markIncomplete(); }
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Decl *getLatestNotUpdated() const {
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assert(NextIsLatest() && "expected a canonical decl");
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if (Next.is<NotKnownLatest>())
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return nullptr;
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return Next.get<KnownLatest>().getNotUpdated();
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}
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};
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static DeclLink PreviousDeclLink(decl_type *D) {
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return DeclLink(DeclLink::PreviousLink, D);
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}
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static DeclLink LatestDeclLink(const ASTContext &Ctx) {
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return DeclLink(DeclLink::LatestLink, Ctx);
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}
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/// \brief Points to the next redeclaration in the chain.
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///
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/// If NextIsPrevious() is true, this is a link to the previous declaration
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/// of this same Decl. If NextIsLatest() is true, this is the first
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/// declaration and Link points to the latest declaration. For example:
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///
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/// #1 int f(int x, int y = 1); // <pointer to #3, true>
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/// #2 int f(int x = 0, int y); // <pointer to #1, false>
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/// #3 int f(int x, int y) { return x + y; } // <pointer to #2, false>
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///
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/// If there is only one declaration, it is <pointer to self, true>
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DeclLink RedeclLink;
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decl_type *First;
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decl_type *getNextRedeclaration() const {
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return RedeclLink.getNext(static_cast<const decl_type *>(this));
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}
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public:
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Redeclarable(const ASTContext &Ctx)
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: RedeclLink(LatestDeclLink(Ctx)), First(static_cast<decl_type *>(this)) {}
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/// \brief Return the previous declaration of this declaration or NULL if this
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/// is the first declaration.
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decl_type *getPreviousDecl() {
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if (RedeclLink.NextIsPrevious())
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return getNextRedeclaration();
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return nullptr;
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}
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const decl_type *getPreviousDecl() const {
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return const_cast<decl_type *>(
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static_cast<const decl_type*>(this))->getPreviousDecl();
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}
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/// \brief Return the first declaration of this declaration or itself if this
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/// is the only declaration.
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decl_type *getFirstDecl() { return First; }
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/// \brief Return the first declaration of this declaration or itself if this
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/// is the only declaration.
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const decl_type *getFirstDecl() const { return First; }
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/// \brief True if this is the first declaration in its redeclaration chain.
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bool isFirstDecl() const { return RedeclLink.NextIsLatest(); }
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/// \brief Returns the most recent (re)declaration of this declaration.
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decl_type *getMostRecentDecl() {
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return getFirstDecl()->getNextRedeclaration();
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}
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/// \brief Returns the most recent (re)declaration of this declaration.
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const decl_type *getMostRecentDecl() const {
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return getFirstDecl()->getNextRedeclaration();
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}
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/// \brief Set the previous declaration. If PrevDecl is NULL, set this as the
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/// first and only declaration.
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void setPreviousDecl(decl_type *PrevDecl);
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/// \brief Iterates through all the redeclarations of the same decl.
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class redecl_iterator {
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/// Current - The current declaration.
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decl_type *Current;
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decl_type *Starter;
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bool PassedFirst;
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public:
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typedef decl_type* value_type;
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typedef decl_type* reference;
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typedef decl_type* pointer;
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typedef std::forward_iterator_tag iterator_category;
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typedef std::ptrdiff_t difference_type;
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redecl_iterator() : Current(nullptr) { }
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explicit redecl_iterator(decl_type *C)
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: Current(C), Starter(C), PassedFirst(false) { }
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reference operator*() const { return Current; }
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pointer operator->() const { return Current; }
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redecl_iterator& operator++() {
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assert(Current && "Advancing while iterator has reached end");
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// Sanity check to avoid infinite loop on invalid redecl chain.
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if (Current->isFirstDecl()) {
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if (PassedFirst) {
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assert(0 && "Passed first decl twice, invalid redecl chain!");
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Current = nullptr;
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return *this;
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}
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PassedFirst = true;
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}
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// Get either previous decl or latest decl.
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decl_type *Next = Current->getNextRedeclaration();
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Current = (Next != Starter) ? Next : nullptr;
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return *this;
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}
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redecl_iterator operator++(int) {
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redecl_iterator tmp(*this);
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++(*this);
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return tmp;
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}
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friend bool operator==(redecl_iterator x, redecl_iterator y) {
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return x.Current == y.Current;
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}
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friend bool operator!=(redecl_iterator x, redecl_iterator y) {
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return x.Current != y.Current;
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}
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};
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typedef llvm::iterator_range<redecl_iterator> redecl_range;
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/// \brief Returns an iterator range for all the redeclarations of the same
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/// decl. It will iterate at least once (when this decl is the only one).
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redecl_range redecls() const {
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return redecl_range(redecl_iterator(const_cast<decl_type *>(
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static_cast<const decl_type *>(this))),
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redecl_iterator());
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}
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redecl_iterator redecls_begin() const { return redecls().begin(); }
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redecl_iterator redecls_end() const { return redecls().end(); }
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friend class ASTDeclReader;
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friend class ASTDeclWriter;
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};
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/// \brief Get the primary declaration for a declaration from an AST file. That
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/// will be the first-loaded declaration.
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Decl *getPrimaryMergedDecl(Decl *D);
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/// \brief Provides common interface for the Decls that cannot be redeclared,
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/// but can be merged if the same declaration is brought in from multiple
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/// modules.
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template<typename decl_type>
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class Mergeable {
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public:
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Mergeable() {}
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/// \brief Return the first declaration of this declaration or itself if this
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/// is the only declaration.
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decl_type *getFirstDecl() {
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decl_type *D = static_cast<decl_type*>(this);
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if (!D->isFromASTFile())
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return D;
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return cast<decl_type>(getPrimaryMergedDecl(const_cast<decl_type*>(D)));
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}
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/// \brief Return the first declaration of this declaration or itself if this
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/// is the only declaration.
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const decl_type *getFirstDecl() const {
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const decl_type *D = static_cast<const decl_type*>(this);
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if (!D->isFromASTFile())
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return D;
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return cast<decl_type>(getPrimaryMergedDecl(const_cast<decl_type*>(D)));
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}
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/// \brief Returns true if this is the first declaration.
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bool isFirstDecl() const { return getFirstDecl() == this; }
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};
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}
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#endif
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