Bitcode: Change reader interface to take memory buffers.

As proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/106595.html

This change also fixes an API oddity where BitstreamCursor::Read() would
return zero for the first read past the end of the bitstream, but would
report_fatal_error for subsequent reads. Now we always report_fatal_error
for all reads past the end. Updated clients to check for the end of the
bitstream before reading from it.

I also needed to add padding to the invalid bitcode tests in
test/Bitcode/. This is because the streaming interface was not checking that
the file size is a multiple of 4.

Differential Revision: https://reviews.llvm.org/D26219

llvm-svn: 285773

1 files changed, 3 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp b/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
index f2090f9..42a97822 100644
--- a/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
+++ b/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
@@ -325,8 +325,8 @@ void ObjectFilePCHContainerReader::ExtractPCH(
       if ((!IsCOFF && Name == "__clangast") || (IsCOFF && Name == "clangast")) {
         StringRef Buf;
         Section.getContents(Buf);
-        return StreamFile.init((const unsigned char *)Buf.begin(),
-                               (const unsigned char *)Buf.end());
+        StreamFile = llvm::BitstreamReader(Buf);
+        return;
       }
     }
   }
@@ -334,8 +334,7 @@ void ObjectFilePCHContainerReader::ExtractPCH(
     if (EIB.convertToErrorCode() ==
         llvm::object::object_error::invalid_file_type)
       // As a fallback, treat the buffer as a raw AST.
-      StreamFile.init((const unsigned char *)Buffer.getBufferStart(),
-                      (const unsigned char *)Buffer.getBufferEnd());
+      StreamFile = llvm::BitstreamReader(Buffer);
     else
       EIB.log(llvm::errs());
   });