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Bitcode: Correctly handle Fixed and VBR arrays in BitstreamCursor::skipRecord(). 

The assertions were wrong; we need to call getEncodingData() on the element,
not the array. While here, simplify the skipRecord() implementation for Fixed
and Char6 arrays. This is tested by the code I added to llvm-bcanalyzer
which makes sure that we can skip any record.

Differential Revision: https://reviews.llvm.org/D27241

llvm-svn: 288315
This commit is contained in:
Peter Collingbourne 2016-12-01 05:47:58 +00:00
parent 2eed75926c
commit cf2750a501
2 changed files with 10 additions and 8 deletions
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10
llvm/lib/Bitcode/Reader/BitstreamReader.cpp
View File

@ -131,18 +131,16 @@ void BitstreamCursor::skipRecord(unsigned AbbrevID) {
default:
report_fatal_error("Array element type can't be an Array or a Blob");
case BitCodeAbbrevOp::Fixed:
assert((unsigned)Op.getEncodingData() <= MaxChunkSize);
for (; NumElts; --NumElts)
Read((unsigned)EltEnc.getEncodingData());
assert((unsigned)EltEnc.getEncodingData() <= MaxChunkSize);
JumpToBit(GetCurrentBitNo() + NumElts * EltEnc.getEncodingData());
break;
case BitCodeAbbrevOp::VBR:
assert((unsigned)Op.getEncodingData() <= MaxChunkSize);
assert((unsigned)EltEnc.getEncodingData() <= MaxChunkSize);
for (; NumElts; --NumElts)
ReadVBR64((unsigned)EltEnc.getEncodingData());
break;
case BitCodeAbbrevOp::Char6:
for (; NumElts; --NumElts)
Read(6);
JumpToBit(GetCurrentBitNo() + NumElts * 6);
break;
}
continue;

8
llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
View File

@ -567,7 +567,7 @@ static bool ParseBlock(BitstreamCursor &Stream, BitstreamBlockInfo &BlockInfo,
++BlockStats.NumRecords;
StringRef Blob;
unsigned CurrentRecordPos = Stream.getCurrentByteNo();
unsigned CurrentRecordPos = Stream.GetCurrentBitNo();
unsigned Code = Stream.readRecord(Entry.ID, Record, &Blob);
// Increment the # occurrences of this code.
@ -608,7 +608,7 @@ static bool ParseBlock(BitstreamCursor &Stream, BitstreamBlockInfo &BlockInfo,
SHA1 Hasher;
StringRef Hash;
{
int BlockSize = CurrentRecordPos - BlockEntryPos;
int BlockSize = (CurrentRecordPos / 8) - BlockEntryPos;
auto Ptr = Stream.getPointerToByte(BlockEntryPos, BlockSize);
Hasher.update(ArrayRef<uint8_t>(Ptr, BlockSize));
Hash = Hasher.result();
@ -675,6 +675,10 @@ static bool ParseBlock(BitstreamCursor &Stream, BitstreamBlockInfo &BlockInfo,
outs() << "\n";
}
// Make sure that we can skip the current record.
Stream.JumpToBit(CurrentRecordPos);
Stream.skipRecord(Entry.ID);
}
}