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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@286207 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 8 deletions

diff --git a/include/clang/Frontend/PCHContainerOperations.h b/include/clang/Frontend/PCHContainerOperations.h
index 0c1b28e9a5..d323fb3e8b 100644
--- a/include/clang/Frontend/PCHContainerOperations.h
+++ b/include/clang/Frontend/PCHContainerOperations.h
@@ -17,7 +17,6 @@
 
 namespace llvm {
 class raw_pwrite_stream;
-class BitstreamReader;
 }
 
 using llvm::StringRef;
@@ -63,10 +62,8 @@ public:
   /// Equivalent to the format passed to -fmodule-format=
   virtual StringRef getFormat() const = 0;
 
-  /// Initialize an llvm::BitstreamReader with the serialized AST inside
-  /// the PCH container Buffer.
-  virtual void ExtractPCH(llvm::MemoryBufferRef Buffer,
-                          llvm::BitstreamReader &StreamFile) const = 0;
+  /// Returns the serialized AST inside the PCH container Buffer.
+  virtual StringRef ExtractPCH(llvm::MemoryBufferRef Buffer) const = 0;
 };
 
 /// Implements write operations for a raw pass-through PCH container.
@@ -87,9 +84,8 @@ class RawPCHContainerWriter : public PCHContainerWriter {
 class RawPCHContainerReader : public PCHContainerReader {
   StringRef getFormat() const override { return "raw"; }
 
-  /// Initialize an llvm::BitstreamReader with Buffer.
-  void ExtractPCH(llvm::MemoryBufferRef Buffer,
-                  llvm::BitstreamReader &StreamFile) const override;
+  /// Simply returns the buffer contained in Buffer.
+  StringRef ExtractPCH(llvm::MemoryBufferRef Buffer) const override;
 };
 
 /// A registry of PCHContainerWriter and -Reader objects for different formats.