4 files changed, 82 insertions, 70 deletions
diff --git a/clang/include/clang/AST/DeclBase.h b/clang/include/clang/AST/DeclBase.h
index 453c8597bf4..3e2435197d2 100644
--- a/clang/include/clang/AST/DeclBase.h
+++ b/clang/include/clang/AST/DeclBase.h
@@ -632,6 +632,8 @@ class DeclContext {
   /// another pointer.
   mutable Decl *LastDecl;
 
+  friend class ExternalASTSource;
+
 protected:
    DeclContext(Decl::Kind K)
      : DeclKind(K), ExternalLexicalStorage(false),
diff --git a/clang/include/clang/AST/ExternalASTSource.h b/clang/include/clang/AST/ExternalASTSource.h
index 79e44511d32..def9ced94c2 100644
--- a/clang/include/clang/AST/ExternalASTSource.h
+++ b/clang/include/clang/AST/ExternalASTSource.h
@@ -58,67 +58,85 @@ public:
 
   virtual ~ExternalASTSource();
 
-  /// \brief Resolve a type ID into a type, potentially building a new
-  /// type.
-  virtual QualType GetType(uint32_t ID) = 0;
-
   /// \brief Resolve a declaration ID into a declaration, potentially
   /// building a new declaration.
-  virtual Decl *GetDecl(uint32_t ID) = 0;
+  ///
+  /// This method only needs to be implemented if the AST source ever
+  /// passes back decl sets as VisibleDeclaration objects.
+  virtual Decl *GetExternalDecl(uint32_t ID) = 0;
 
   /// \brief Resolve a selector ID into a selector.
-  virtual Selector GetSelector(uint32_t ID) = 0;
+  ///
+  /// This operation only needs to be implemented if the AST source
+  /// returns non-zero for GetNumKnownSelectors().
+  virtual Selector GetExternalSelector(uint32_t ID) = 0;
 
   /// \brief Returns the number of selectors known to the external AST
   /// source.
-  virtual uint32_t GetNumKnownSelectors() = 0;
+  virtual uint32_t GetNumExternalSelectors() = 0;
 
-  /// \brief Resolve the offset of a statement in the decl stream into a
-  /// statement.
+  /// \brief Resolve the offset of a statement in the decl stream into
+  /// a statement.
   ///
-  /// This operation will read a new statement from the external
-  /// source each time it is called, and is meant to be used via a
-  /// LazyOffsetPtr.
-  virtual Stmt *GetDeclStmt(uint64_t Offset) = 0;
+  /// This operation is meant to be used via a LazyOffsetPtr.  It only
+  /// needs to be implemented if the AST source uses methods like
+  /// FunctionDecl::setLazyBody when building decls.
+  virtual Stmt *GetExternalDeclStmt(uint64_t Offset) = 0;
 
-  /// \brief Read all of the declarations lexically stored in a
-  /// declaration context.
+  /// \brief Finds all declarations with the given name in the
+  /// given context.
   ///
-  /// \param DC The declaration context whose declarations will be
-  /// read.
+  /// Generally the final step of this method is either to call
+  /// SetExternalVisibleDeclsForName or to recursively call lookup on
+  /// the DeclContext after calling SetExternalVisibleDecls.
+  virtual DeclContext::lookup_result
+  FindExternalVisibleDeclsByName(const DeclContext *DC,
+                                 DeclarationName Name) = 0;
+
+  /// \brief Finds all declarations lexically contained within the given
+  /// DeclContext.
   ///
-  /// \param Decls Vector that will contain the declarations loaded
-  /// from the external source. The caller is responsible for merging
-  /// these declarations with any declarations already stored in the
-  /// declaration context.
-  ///
-  /// \returns true if there was an error while reading the
-  /// declarations for this declaration context.
-  virtual bool ReadDeclsLexicallyInContext(DeclContext *DC,
-                                  llvm::SmallVectorImpl<uint32_t> &Decls) = 0;
-
-  /// \brief Read all of the declarations visible from a declaration
-  /// context.
-  ///
-  /// \param DC The declaration context whose visible declarations
-  /// will be read.
-  ///
-  /// \param Decls A vector of visible declaration structures,
-  /// providing the mapping from each name visible in the declaration
-  /// context to the declaration IDs of declarations with that name.
-  ///
-  /// \returns true if there was an error while reading the
-  /// declarations for this declaration context.
-  virtual bool ReadDeclsVisibleInContext(DeclContext *DC,
-                       llvm::SmallVectorImpl<VisibleDeclaration> & Decls) = 0;
+  /// \return true if an error occurred
+  virtual bool FindExternalLexicalDecls(const DeclContext *DC,
+                                llvm::SmallVectorImpl<Decl*> &Result) = 0;
 
   /// \brief Function that will be invoked when we begin parsing a new
   /// translation unit involving this external AST source.
+  ///
+  /// The default implementation of this method is a no-op.
   virtual void StartTranslationUnit(ASTConsumer *Consumer) { }
 
   /// \brief Print any statistics that have been gathered regarding
   /// the external AST source.
+  ///
+  /// The default implementation of this method is a no-op.
   virtual void PrintStats();
+
+protected:
+  /// \brief Initialize the context's lookup map with the given decls.
+  /// It is assumed that none of the declarations are redeclarations of
+  /// each other.
+  static void SetExternalVisibleDecls(const DeclContext *DC,
+                  const llvm::SmallVectorImpl<VisibleDeclaration> &Decls);
+
+  /// \brief Initialize the context's lookup map with the given decls.
+  /// It is assumed that none of the declarations are redeclarations of
+  /// each other.
+  static void SetExternalVisibleDecls(const DeclContext *DC,
+                              const llvm::SmallVectorImpl<NamedDecl*> &Decls);
+
+  static DeclContext::lookup_result
+  SetExternalVisibleDeclsForName(const DeclContext *DC,
+                                 const VisibleDeclaration &VD);
+
+  static DeclContext::lookup_result
+  SetExternalVisibleDeclsForName(const DeclContext *DC,
+                                 DeclarationName Name,
+                                 llvm::SmallVectorImpl<NamedDecl*> &Decls);
+
+  static DeclContext::lookup_result
+  SetNoExternalVisibleDeclsForName(const DeclContext *DC,
+                                   DeclarationName Name);
 };
 
 /// \brief A lazy pointer to an AST node (of base type T) that resides
@@ -185,7 +203,8 @@ public:
 };
 
 /// \brief A lazy pointer to a statement.
-typedef LazyOffsetPtr<Stmt, &ExternalASTSource::GetDeclStmt> LazyDeclStmtPtr;
+typedef LazyOffsetPtr<Stmt, &ExternalASTSource::GetExternalDeclStmt>
+  LazyDeclStmtPtr;
 
 } // end namespace clang
 
diff --git a/clang/include/clang/Frontend/PCHReader.h b/clang/include/clang/Frontend/PCHReader.h
index e144738236e..b6881edce94 100644
--- a/clang/include/clang/Frontend/PCHReader.h
+++ b/clang/include/clang/Frontend/PCHReader.h
@@ -570,29 +570,37 @@ public:
                              const RecordData &Record, unsigned &Idx);
 
   /// \brief Reads a declarator info from the given record.
-  virtual TypeSourceInfo *GetTypeSourceInfo(const RecordData &Record,
-                                            unsigned &Idx);
+  TypeSourceInfo *GetTypeSourceInfo(const RecordData &Record,
+                                    unsigned &Idx);
 
   /// \brief Resolve a type ID into a type, potentially building a new
   /// type.
-  virtual QualType GetType(pch::TypeID ID);
+  QualType GetType(pch::TypeID ID);
 
   /// \brief Resolve a declaration ID into a declaration, potentially
   /// building a new declaration.
-  virtual Decl *GetDecl(pch::DeclID ID);
+  Decl *GetDecl(pch::DeclID ID);
+  virtual Decl *GetExternalDecl(uint32_t ID);
 
   /// \brief Resolve the offset of a statement into a statement.
   ///
   /// This operation will read a new statement from the external
   /// source each time it is called, and is meant to be used via a
   /// LazyOffsetPtr (which is used by Decls for the body of functions, etc).
-  virtual Stmt *GetDeclStmt(uint64_t Offset);
+  virtual Stmt *GetExternalDeclStmt(uint64_t Offset);
 
   /// ReadBlockAbbrevs - Enter a subblock of the specified BlockID with the
   /// specified cursor.  Read the abbreviations that are at the top of the block
   /// and then leave the cursor pointing into the block.
   bool ReadBlockAbbrevs(llvm::BitstreamCursor &Cursor, unsigned BlockID);
 
+  /// \brief Finds all the visible declarations with a given name.
+  /// The current implementation of this method just loads the entire
+  /// lookup table as unmaterialized references.
+  virtual DeclContext::lookup_result
+  FindExternalVisibleDeclsByName(const DeclContext *DC,
+                                 DeclarationName Name);
+
   /// \brief Read all of the declarations lexically stored in a
   /// declaration context.
   ///
@@ -606,27 +614,8 @@ public:
   ///
   /// \returns true if there was an error while reading the
   /// declarations for this declaration context.
-  virtual bool ReadDeclsLexicallyInContext(DeclContext *DC,
-                                 llvm::SmallVectorImpl<pch::DeclID> &Decls);
-
-  /// \brief Read all of the declarations visible from a declaration
-  /// context.
-  ///
-  /// \param DC The declaration context whose visible declarations
-  /// will be read.
-  ///
-  /// \param Decls A vector of visible declaration structures,
-  /// providing the mapping from each name visible in the declaration
-  /// context to the declaration IDs of declarations with that name.
-  ///
-  /// \returns true if there was an error while reading the
-  /// declarations for this declaration context.
-  ///
-  /// FIXME: Using this intermediate data structure results in an
-  /// extraneous copying of the data. Could we pass in a reference to
-  /// the StoredDeclsMap instead?
-  virtual bool ReadDeclsVisibleInContext(DeclContext *DC,
-                       llvm::SmallVectorImpl<VisibleDeclaration> & Decls);
+  virtual bool FindExternalLexicalDecls(const DeclContext *DC,
+                                        llvm::SmallVectorImpl<Decl*> &Decls);
 
   /// \brief Function that will be invoked when we begin parsing a new
   /// translation unit involving this external AST source.
@@ -691,8 +680,8 @@ public:
 
   Selector DecodeSelector(unsigned Idx);
 
-  virtual Selector GetSelector(uint32_t ID);
-  virtual uint32_t GetNumKnownSelectors();
+  virtual Selector GetExternalSelector(uint32_t ID);
+  uint32_t GetNumExternalSelectors();
 
   Selector GetSelector(const RecordData &Record, unsigned &Idx) {
     return DecodeSelector(Record[Idx++]);
diff --git a/clang/include/clang/Sema/ExternalSemaSource.h b/clang/include/clang/Sema/ExternalSemaSource.h
index d27e29281b5..ad42a847fa4 100644
--- a/clang/include/clang/Sema/ExternalSemaSource.h
+++ b/clang/include/clang/Sema/ExternalSemaSource.h
@@ -29,6 +29,8 @@ public:
     ExternalASTSource::SemaSource = true;
   }
 
+  ~ExternalSemaSource();
+
   /// \brief Initialize the semantic source with the Sema instance
   /// being used to perform semantic analysis on the abstract syntax
   /// tree.