[llvm] r333942 - Fix for llvm-dis/llvm-bcanalyzer overflows

[Teresa Johnson via llvm-commits]

Author: tejohnson
Date: Mon Jun  4 12:20:02 2018
New Revision: 333942

URL: http://llvm.org/viewvc/llvm-project?rev=333942&view=rev
Log:
Fix for llvm-dis/llvm-bcanalyzer overflows

Summary:
These tools failed for a very large bitcode file produced by LTO due to
64-bit values being assigned to 32-bit types. For the BitstreamReader.h
fix, the value initially fit into the 32-bit unsigned, but there was an
overflow when multiplying by 32 furter below to compute the bit offset.

No test case in the patch as this requires a huge bitcode file.

Reviewers: pcc, george.karpenkov

Subscribers: mehdi_amini, a.sidorin, llvm-commits

Differential Revision: https://reviews.llvm.org/D47731

Modified:
    llvm/trunk/include/llvm/Bitcode/BitstreamReader.h
    llvm/trunk/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp

Modified: llvm/trunk/include/llvm/Bitcode/BitstreamReader.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Bitcode/BitstreamReader.h?rev=333942&r1=333941&r2=333942&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Bitcode/BitstreamReader.h (original)
+++ llvm/trunk/include/llvm/Bitcode/BitstreamReader.h Mon Jun  4 12:20:02 2018
@@ -429,7 +429,7 @@ public:
     // don't care what code widths are used inside of it.
     ReadVBR(bitc::CodeLenWidth);
     SkipToFourByteBoundary();
-    unsigned NumFourBytes = Read(bitc::BlockSizeWidth);
+    size_t NumFourBytes = Read(bitc::BlockSizeWidth);
 
     // Check that the block wasn't partially defined, and that the offset isn't
     // bogus.

Modified: llvm/trunk/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp?rev=333942&r1=333941&r2=333942&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp (original)
+++ llvm/trunk/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp Mon Jun  4 12:20:02 2018
@@ -602,7 +602,7 @@ static bool ParseBlock(BitstreamCursor &
     ++BlockStats.NumRecords;
 
     StringRef Blob;
-    unsigned CurrentRecordPos = Stream.GetCurrentBitNo();
+    uint64_t CurrentRecordPos = Stream.GetCurrentBitNo();
     unsigned Code = Stream.readRecord(Entry.ID, Record, &Blob);
 
     // Increment the # occurrences of this code.