From: Peter Collingbourne <peter@pcc.me.uk>
Date: Thu, 27 Oct 2016 21:39:28 +0000 (+0000)
Subject: BitcodeReader: Require clients to read the block info block at most once.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0f84babf62b3c369f3cf06adbe7620d41ee5cc6e;p=llvm

BitcodeReader: Require clients to read the block info block at most once.

This change makes it the client's responsibility to call ReadBlockInfoBlock()
at most once. This is in preparation for a future change that will allow
there to be multiple block info blocks.

See also: http://lists.llvm.org/pipermail/llvm-dev/2016-October/106512.html

Differential Revision: https://reviews.llvm.org/D26016

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285350 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Bitcode/Reader/BitstreamReader.cpp b/lib/Bitcode/Reader/BitstreamReader.cpp
index 330bc045cc6..0b549f7550f 100644
--- a/lib/Bitcode/Reader/BitstreamReader.cpp
+++ b/lib/Bitcode/Reader/BitstreamReader.cpp
@@ -319,9 +319,9 @@ void BitstreamCursor::ReadAbbrevRecord() {
 }
 
 bool BitstreamCursor::ReadBlockInfoBlock() {
-  // If this is the second stream to get to the block info block, skip it.
+  // We expect the client to read the block info block at most once.
   if (getBitStreamReader()->hasBlockInfoRecords())
-    return SkipBlock();
+    report_fatal_error("Duplicate read of block info block");
 
   if (EnterSubBlock(bitc::BLOCKINFO_BLOCK_ID)) return true;