From 69aecc6252bf4a5ee59f9b51c3728ea07b6342bf Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Wed, 27 Oct 2010 20:23:41 +0000
Subject: [PATCH] Lazily load the next friend in the chain of FriendDecls, to
 eliminate some excessive recursion and deserialization.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@117480 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/AST/DeclFriend.h      | 13 +++++++++----
 lib/Serialization/ASTReaderDecl.cpp |  2 +-
 lib/Serialization/ASTWriterDecl.cpp |  2 +-
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/include/clang/AST/DeclFriend.h b/include/clang/AST/DeclFriend.h
index 10befe0831..20d6da19b8 100644
--- a/include/clang/AST/DeclFriend.h
+++ b/include/clang/AST/DeclFriend.h
@@ -43,7 +43,7 @@ private:
   FriendUnion Friend;
 
   // A pointer to the next friend in the sequence.
-  FriendDecl *NextFriend;
+  LazyDeclPtr NextFriend;
 
   // Location of the 'friend' specifier.
   SourceLocation FriendLoc;
@@ -60,14 +60,19 @@ private:
              SourceLocation FriendL)
     : Decl(Decl::Friend, DC, L),
       Friend(Friend),
-      NextFriend(0),
+      NextFriend(),
       FriendLoc(FriendL),
       UnsupportedFriend(false) {
   }
 
   explicit FriendDecl(EmptyShell Empty)
-    : Decl(Decl::Friend, Empty), NextFriend(0) { }
+    : Decl(Decl::Friend, Empty), NextFriend() { }
 
+  FriendDecl *getNextFriend() {
+    return cast_or_null<FriendDecl>(
+                          NextFriend.get(getASTContext().getExternalSource()));
+  }
+  
 public:
   static FriendDecl *Create(ASTContext &C, DeclContext *DC,
                             SourceLocation L, FriendUnion Friend_,
@@ -129,7 +134,7 @@ public:
 
   friend_iterator &operator++() {
     assert(Ptr && "attempt to increment past end of friend list");
-    Ptr = Ptr->NextFriend;
+    Ptr = Ptr->getNextFriend();
     return *this;
   }
 
diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 4b1d48162e..322a67176f 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -933,7 +933,7 @@ void ASTDeclReader::VisitFriendDecl(FriendDecl *D) {
     D->Friend = GetTypeSourceInfo(Record, Idx);
   else
     D->Friend = cast<NamedDecl>(Reader.GetDecl(Record[Idx++]));
-  D->NextFriend = cast_or_null<FriendDecl>(Reader.GetDecl(Record[Idx++]));
+  D->NextFriend = Record[Idx++];
   D->UnsupportedFriend = (Record[Idx++] != 0);
   D->FriendLoc = ReadSourceLocation(Record, Idx);
 }
diff --git a/lib/Serialization/ASTWriterDecl.cpp b/lib/Serialization/ASTWriterDecl.cpp
index 4e479b33de..46f62b7d84 100644
--- a/lib/Serialization/ASTWriterDecl.cpp
+++ b/lib/Serialization/ASTWriterDecl.cpp
@@ -803,7 +803,7 @@ void ASTDeclWriter::VisitFriendDecl(FriendDecl *D) {
     Writer.AddTypeSourceInfo(D->Friend.get<TypeSourceInfo*>(), Record);
   else
     Writer.AddDeclRef(D->Friend.get<NamedDecl*>(), Record);
-  Writer.AddDeclRef(D->NextFriend, Record);
+  Writer.AddDeclRef(D->getNextFriend(), Record);
   Record.push_back(D->UnsupportedFriend);
   Writer.AddSourceLocation(D->FriendLoc, Record);
   Code = serialization::DECL_FRIEND;
-- 
2.40.0