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fix some type confusion in ReadVBR64: "Piece" should be only 32 bits,

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not 64, because we read at most 32 bits at a time.  OTOH, "Result" must
be 64-bits and insertion into it must be 64-bit clean.  Thanks to Ivan
Sorokin for bringing this up.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74932 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2009-07-07 18:39:49 +00:00
parent a9d1f2c559
commit f5a1edce23
1 changed files with 8 additions and 5 deletions
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13
include/llvm/Bitcode/BitstreamReader.h
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@ -260,6 +260,7 @@ public:
uint32_t Read(unsigned NumBits) { uint32_t Read(unsigned NumBits) {
assert(NumBits <= 32 && "Cannot return more than 32 bits!");
// If the field is fully contained by CurWord, return it quickly. // If the field is fully contained by CurWord, return it quickly.
if (BitsInCurWord >= NumBits) { if (BitsInCurWord >= NumBits) {
uint32_t R = CurWord & ((1U << NumBits)-1); uint32_t R = CurWord & ((1U << NumBits)-1);
@ -322,17 +323,19 @@ public:
} }
} }
// ReadVBR64 - Read a VBR that may have a value up to 64-bits in size. The
// chunk size of the VBR must still be <= 32 bits though.
uint64_t ReadVBR64(unsigned NumBits) { uint64_t ReadVBR64(unsigned NumBits) {
uint64_t Piece = Read(NumBits); uint32_t Piece = Read(NumBits);
if ((Piece & (uint64_t(1) << (NumBits-1))) == 0) if ((Piece & (1U << (NumBits-1))) == 0)
return Piece; return uint64_t(Piece);
uint64_t Result = 0; uint64_t Result = 0;
unsigned NextBit = 0; unsigned NextBit = 0;
while (1) { while (1) {
Result |= (Piece & ((1U << (NumBits-1))-1)) << NextBit; Result |= uint64_t(Piece & ((1U << (NumBits-1))-1)) << NextBit;
if ((Piece & (uint64_t(1) << (NumBits-1))) == 0) if ((Piece & (1U << (NumBits-1))) == 0)
return Result; return Result;
NextBit += NumBits-1; NextBit += NumBits-1;