Instead of modifying the ObjC AST to not modify existing declarations, teach chained PCH to overwrite declarations from earlier PCH files in dependent ones. Tell Sema to note when it changes AST nodes so that they have to be reserialized. Finally, the ObjCProtocolDecls created in forward decls, like the ObjCInterfaceDecls in @class forward decls, are not lexically part of the decl context; only the definition is.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110989 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 22 insertions, 0 deletions

diff --git a/lib/Frontend/PCHWriter.cpp b/lib/Frontend/PCHWriter.cpp
index d7da4fc41c..a86bdb9278 100644
--- a/lib/Frontend/PCHWriter.cpp
+++ b/lib/Frontend/PCHWriter.cpp
@@ -2414,6 +2414,8 @@ void PCHWriter::WritePCHChain(Sema &SemaRef, MemorizeStatCalls *StatCalls,
        I != E; ++I) {
     if ((*I)->getPCHLevel() == 0)
       NewGlobalDecls.push_back(GetDeclRef(*I));
+    else if ((*I)->isChangedSinceDeserialization())
+      (void)GetDeclRef(*I); // Make sure it's written, but don't record it.
   }
   // We also need to write a lexical updates block for the TU.
   llvm::BitCodeAbbrev *Abv = new llvm::BitCodeAbbrev();
@@ -2596,10 +2598,24 @@ void PCHWriter::WritePCHChain(Sema &SemaRef, MemorizeStatCalls *StatCalls,
   Record.push_back(NumMacros);
   Record.push_back(NumLexicalDeclContexts);
   Record.push_back(NumVisibleDeclContexts);
+  WriteDeclUpdateBlock();
   Stream.EmitRecord(pch::STATISTICS, Record);
   Stream.ExitBlock();
 }
 
+void PCHWriter::WriteDeclUpdateBlock() {
+  if (ReplacedDecls.empty())
+    return;
+
+  RecordData Record;
+  for (llvm::SmallVector<std::pair<pch::DeclID, uint64_t>, 16>::iterator
+           I = ReplacedDecls.begin(), E = ReplacedDecls.end(); I != E; ++I) {
+    Record.push_back(I->first);
+    Record.push_back(I->second);
+  }
+  Stream.EmitRecord(pch::DECL_REPLACEMENTS, Record);
+}
+
 void PCHWriter::AddSourceLocation(SourceLocation Loc, RecordData &Record) {
   Record.push_back(Loc.getRawEncoding());
 }
@@ -2817,6 +2833,12 @@ pch::DeclID PCHWriter::GetDeclRef(const Decl *D) {
     // enqueue it in the list of declarations to emit.
     ID = NextDeclID++;
     DeclTypesToEmit.push(const_cast<Decl *>(D));
+  } else if (ID < FirstDeclID && D->isChangedSinceDeserialization()) {
+    // We don't add it to the replacement collection here, because we don't
+    // have the offset yet.
+    DeclTypesToEmit.push(const_cast<Decl *>(D));
+    // Reset the flag, so that we don't add this decl multiple times.
+    const_cast<Decl *>(D)->setChangedSinceDeserialization(false);
   }
 
   return ID;