Bitcode: Decouple block info block state from reader.

As proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/106630.html

Move block info block state to a new class, BitstreamBlockInfo.
Clients may set the block info for a particular cursor with the
BitstreamCursor::setBlockInfo() method.

At this point BitstreamReader is not much more than a container for an
ArrayRef<uint8_t>, so remove it and replace all uses with direct uses
of memory buffers.

Differential Revision: https://reviews.llvm.org/D26259

llvm-svn: 286207

1 files changed, 2 insertions, 7 deletions

diff --git a/clang/lib/Serialization/GlobalModuleIndex.cpp b/clang/lib/Serialization/GlobalModuleIndex.cpp
index e55ed40b227..9f986d54a98 100644
--- a/clang/lib/Serialization/GlobalModuleIndex.cpp
+++ b/clang/lib/Serialization/GlobalModuleIndex.cpp
@@ -245,11 +245,8 @@ GlobalModuleIndex::readIndex(StringRef Path) {
     return std::make_pair(nullptr, EC_NotFound);
   std::unique_ptr<llvm::MemoryBuffer> Buffer = std::move(BufferOrErr.get());
 
-  /// \brief The bitstream reader from which we'll read the AST file.
-  llvm::BitstreamReader Reader(*Buffer);
-
   /// \brief The main bitstream cursor for the main block.
-  llvm::BitstreamCursor Cursor(Reader);
+  llvm::BitstreamCursor Cursor(*Buffer);
 
   // Sniff for the signature.
   if (Cursor.Read(8) != 'B' ||
@@ -503,9 +500,7 @@ bool GlobalModuleIndexBuilder::loadModuleFile(const FileEntry *File) {
   }
 
   // Initialize the input stream
-  llvm::BitstreamReader InStreamFile;
-  PCHContainerRdr.ExtractPCH((*Buffer)->getMemBufferRef(), InStreamFile);
-  llvm::BitstreamCursor InStream(InStreamFile);
+  llvm::BitstreamCursor InStream(PCHContainerRdr.ExtractPCH(**Buffer));
 
   // Sniff for the signature.
   if (InStream.Read(8) != 'C' ||