From a126651270acf17c434f60f86a3ab3687f87813a Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Mon, 19 Dec 2011 21:09:25 +0000
Subject: [PATCH] Eliminate the first->last redeclaration map from the AST file
 format. It's no longer being used, now that we have a new implementation of
 redeclaration chains.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146905 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Serialization/ASTBitCodes.h | 18 +++++++-----------
 include/clang/Serialization/ASTReader.h   |  6 ------
 lib/Serialization/ASTReader.cpp           | 10 ----------
 lib/Serialization/ASTWriter.cpp           | 21 +++++----------------
 4 files changed, 12 insertions(+), 43 deletions(-)

diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
index cce6916b4e..a4b6b8f45e 100644
--- a/include/clang/Serialization/ASTBitCodes.h
+++ b/include/clang/Serialization/ASTBitCodes.h
@@ -366,10 +366,10 @@ namespace clang {
       /// \brief Record code for an update to the TU's lexically contained
       /// declarations.
       TU_UPDATE_LEXICAL = 28,
-
-      /// \brief Record code for an update to first decls pointing to the
-      /// latest redeclarations.
-      REDECLS_UPDATE_LATEST = 29,
+      
+      /// \brief Record code for the array describing the first/last local
+      /// redeclarations of each entity.
+      LOCAL_REDECLARATIONS = 29,
 
       /// \brief Record code for declarations that Sema keeps references of.
       SEMA_DECL_REFS = 30,
@@ -445,18 +445,14 @@ namespace clang {
 
       /// \brief Record code for ObjC categories in a module that are chained to
       /// an interface.
-      OBJC_CHAINED_CATEGORIES,
+      OBJC_CHAINED_CATEGORIES = 49,
 
       /// \brief Record code for a file sorted array of DeclIDs in a module.
-      FILE_SORTED_DECLS,
+      FILE_SORTED_DECLS = 50,
       
       /// \brief Record code for an array of all of the (sub)modules that were
       /// imported by the AST file.
-      IMPORTED_MODULES,
-      
-      /// \brief Record code for the array describing the first/last local
-      /// redeclarations of each entity.
-      LOCAL_REDECLARATIONS
+      IMPORTED_MODULES = 51
     };
 
     /// \brief Record types used within a source manager block.
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index bbeacb4f22..fd0a897518 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -333,12 +333,6 @@ private:
   /// declarations that have not yet been linked to their definitions.
   llvm::SmallPtrSet<Decl *, 4> PendingDefinitions;
   
-  typedef llvm::DenseMap<serialization::DeclID, serialization::DeclID>
-      FirstLatestDeclIDMap;
-  /// \brief Map of first declarations from a chained PCH that point to the
-  /// most recent declarations in another AST file.
-  FirstLatestDeclIDMap FirstLatestDeclIDs;
-
   /// \brief Set of ObjC interfaces that have categories chained to them in
   /// other modules.
   llvm::DenseSet<serialization::GlobalDeclID> ObjCChainedCategoriesInterfaces;
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index bc4fa668b3..1efc95408b 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -1882,16 +1882,6 @@ ASTReader::ReadASTBlock(ModuleFile &F) {
       break;
     }
 
-    case REDECLS_UPDATE_LATEST: {
-      assert(Record.size() % 2 == 0 && "Expected pairs of DeclIDs");
-      for (unsigned i = 0, e = Record.size(); i < e; /* in loop */) {
-        DeclID First = ReadDeclID(F, Record, i);
-        DeclID Latest = ReadDeclID(F, Record, i);
-        FirstLatestDeclIDs[First] = Latest;
-      }
-      break;
-    }
-
     case LANGUAGE_OPTIONS:
       if (ParseLanguageOptions(Record) && !DisableValidation)
         return IgnorePCH;
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index e1af601614..1776b97bb0 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -778,7 +778,7 @@ void ASTWriter::WriteBlockInfoBlock() {
   RECORD(IMPORTS);
   RECORD(REFERENCED_SELECTOR_POOL);
   RECORD(TU_UPDATE_LEXICAL);
-  RECORD(REDECLS_UPDATE_LATEST);
+  RECORD(LOCAL_REDECLARATIONS);
   RECORD(SEMA_DECL_REFS);
   RECORD(WEAK_UNDECLARED_IDENTIFIERS);
   RECORD(PENDING_IMPLICIT_INSTANTIATIONS);
@@ -798,8 +798,10 @@ void ASTWriter::WriteBlockInfoBlock() {
   RECORD(KNOWN_NAMESPACES);
   RECORD(MODULE_OFFSET_MAP);
   RECORD(SOURCE_MANAGER_LINE_TABLE);
-  RECORD(LOCAL_REDECLARATIONS);
-         
+  RECORD(OBJC_CHAINED_CATEGORIES);
+  RECORD(FILE_SORTED_DECLS);
+  RECORD(IMPORTED_MODULES);
+  
   // SourceManager Block.
   BLOCK(SOURCE_MANAGER_BLOCK);
   RECORD(SM_SLOC_FILE_ENTRY);
@@ -3313,19 +3315,6 @@ void ASTWriter::WriteASTCore(Sema &SemaRef, MemorizeStatCalls *StatCalls,
 
   Stream.EmitRecord(SPECIAL_TYPES, SpecialTypes);
 
-  /// Build a record containing first declarations from a chained PCH and the
-  /// most recent declarations in this AST that they point to.
-  RecordData FirstLatestDeclIDs;
-  for (FirstLatestDeclMap::iterator I = FirstLatestDecls.begin(), 
-                                    E = FirstLatestDecls.end(); 
-       I != E; ++I) {
-    AddDeclRef(I->first, FirstLatestDeclIDs);
-    AddDeclRef(I->second, FirstLatestDeclIDs);
-  }
-  
-  if (!FirstLatestDeclIDs.empty())
-    Stream.EmitRecord(REDECLS_UPDATE_LATEST, FirstLatestDeclIDs);
-
   // Write the record containing external, unnamed definitions.
   if (!ExternalDefinitions.empty())
     Stream.EmitRecord(EXTERNAL_DEFINITIONS, ExternalDefinitions);