commit 24a224c9dd91b2a8c673f170f343b7884a5c68de
author Douglas Gregor <doug.gregor@gmail.com> Sat Apr 25 18:35:21 2009 +0000
committer Douglas Gregor <doug.gregor@gmail.com> Sat Apr 25 18:35:21 2009 +0000
tree b2778f92a10f8202a569331f23901443dc3253bf
parent 2d71183cd5b0a6bd39cab83e42ab182b0ab445d6

Write the declaration and type offset arrays into the bitstream as
blobs, so that we don't need to do any work to get these arrays into
memory at PCH load time.

This gives another 19% performance improvement to the Cocoa-prefixed
"Hello, World!".



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@70059 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Frontend/PCHWriter.cpp

diff --git a/lib/Frontend/PCHWriter.cpp b/lib/Frontend/PCHWriter.cpp
index 56c8296..91ddbf4 100644
--- a/lib/Frontend/PCHWriter.cpp
+++ b/lib/Frontend/PCHWriter.cpp
@@ -2270,6 +2270,8 @@
     NumVisibleDeclContexts(0) { }
 
 void PCHWriter::WritePCH(Sema &SemaRef) {
+  using namespace llvm;
+
   ASTContext &Context = SemaRef.Context;
   Preprocessor &PP = SemaRef.PP;
 
@@ -2315,7 +2317,7 @@
 
   // Write the remaining PCH contents.
   RecordData Record;
-  Stream.EnterSubblock(pch::PCH_BLOCK_ID, 3);
+  Stream.EnterSubblock(pch::PCH_BLOCK_ID, 4);
   WriteTargetTriple(Context.Target);
   WriteLanguageOptions(Context.getLangOptions());
   WriteSourceManagerBlock(Context.getSourceManager());
@@ -2324,8 +2326,32 @@
   WriteDeclsBlock(Context);
   WriteMethodPool(SemaRef);
   WriteIdentifierTable(PP);
-  Stream.EmitRecord(pch::TYPE_OFFSET, TypeOffsets);
-  Stream.EmitRecord(pch::DECL_OFFSET, DeclOffsets);
+
+  // Write the type offsets array
+  BitCodeAbbrev *Abbrev = new BitCodeAbbrev();
+  Abbrev->Add(BitCodeAbbrevOp(pch::TYPE_OFFSET));
+  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // # of types
+  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob)); // types block
+  unsigned TypeOffsetAbbrev = Stream.EmitAbbrev(Abbrev);
+  Record.clear();
+  Record.push_back(pch::TYPE_OFFSET);
+  Record.push_back(TypeOffsets.size());
+  Stream.EmitRecordWithBlob(TypeOffsetAbbrev, Record,
+                            (const char *)&TypeOffsets.front(), 
+                            TypeOffsets.size() * sizeof(uint64_t));
+  
+  // Write the declaration offsets array
+  Abbrev = new BitCodeAbbrev();
+  Abbrev->Add(BitCodeAbbrevOp(pch::DECL_OFFSET));
+  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32)); // # of declarations
+  Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob)); // declarations block
+  unsigned DeclOffsetAbbrev = Stream.EmitAbbrev(Abbrev);
+  Record.clear();
+  Record.push_back(pch::DECL_OFFSET);
+  Record.push_back(DeclOffsets.size());
+  Stream.EmitRecordWithBlob(DeclOffsetAbbrev, Record,
+                            (const char *)&DeclOffsets.front(), 
+                            DeclOffsets.size() * sizeof(uint64_t));
 
   // Write the record of special types.
   Record.clear();