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r173072 is causing some regressions on big endian hosts, I don't have time to debug it

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so revert it for now.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173074 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2013-01-21 19:08:15 +00:00
parent 02b206f6d8
commit dc60fc1aa7
1 changed files with 21 additions and 49 deletions
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70
include/llvm/Bitcode/BitstreamReader.h
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@ -170,17 +170,12 @@ class BitstreamCursor {
BitstreamReader *BitStream; BitstreamReader *BitStream;
size_t NextChar; size_t NextChar;
/// CurWord - This is the current data we have pulled from the stream but have
/// CurWord/word_t - This is the current data we have pulled from the stream /// not returned to the client.
/// but have not returned to the client. This is specifically and uint32_t CurWord;
/// intentionally defined to follow the word size of the host machine for
/// efficiency. We use word_t in places that are aware of this to make it
/// perfectly explicit what is going on.
typedef size_t word_t;
word_t CurWord;
/// BitsInCurWord - This is the number of bits in CurWord that are valid. This /// BitsInCurWord - This is the number of bits in CurWord that are valid. This
/// is always from [0...31/63] inclusive (depending on word size). /// is always from [0...31] inclusive.
unsigned BitsInCurWord; unsigned BitsInCurWord;
// CurCodeSize - This is the declared size of code values used for the current // CurCodeSize - This is the declared size of code values used for the current
@ -323,8 +318,8 @@ public:
/// JumpToBit - Reset the stream to the specified bit number. /// JumpToBit - Reset the stream to the specified bit number.
void JumpToBit(uint64_t BitNo) { void JumpToBit(uint64_t BitNo) {
uintptr_t ByteNo = uintptr_t(BitNo/8) & ~(sizeof(word_t)-1); uintptr_t ByteNo = uintptr_t(BitNo/8) & ~3;
unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1)); uintptr_t WordBitNo = uintptr_t(BitNo) & 31;
assert(canSkipToPos(ByteNo) && "Invalid location"); assert(canSkipToPos(ByteNo) && "Invalid location");
// Move the cursor to the right word. // Move the cursor to the right word.
@ -333,12 +328,8 @@ public:
CurWord = 0; CurWord = 0;
// Skip over any bits that are already consumed. // Skip over any bits that are already consumed.
if (WordBitNo) { if (WordBitNo)
if (sizeof(word_t) > 4) Read(static_cast<unsigned>(WordBitNo));
Read64(WordBitNo);
else
Read(WordBitNo);
}
} }
@ -346,7 +337,7 @@ public:
assert(NumBits <= 32 && "Cannot return more than 32 bits!"); 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 = uint32_t(CurWord) & (~0U >> (32-NumBits)); uint32_t R = CurWord & ((1U << NumBits)-1);
CurWord >>= NumBits; CurWord >>= NumBits;
BitsInCurWord -= NumBits; BitsInCurWord -= NumBits;
return R; return R;
@ -359,32 +350,24 @@ public:
return 0; return 0;
} }
uint32_t R = uint32_t(CurWord); unsigned R = CurWord;
// Read the next word from the stream. // Read the next word from the stream.
uint8_t buf[sizeof(word_t)] = {0}; CurWord = getWord(NextChar);
BitStream->getBitcodeBytes().readBytes(NextChar, sizeof(buf), buf, NULL); NextChar += 4;
typedef support::detail::packed_endian_specific_integral
<word_t, support::little, support::unaligned> Endian_T;
CurWord = *reinterpret_cast<Endian_T*>(buf);
NextChar += sizeof(word_t);
// Extract NumBits-BitsInCurWord from what we just read. // Extract NumBits-BitsInCurWord from what we just read.
unsigned BitsLeft = NumBits-BitsInCurWord; unsigned BitsLeft = NumBits-BitsInCurWord;
// Be careful here, BitsLeft is in the range [1..32]/[1..64] inclusive. // Be careful here, BitsLeft is in the range [1..32] inclusive.
R |= uint32_t((CurWord & (word_t(~0ULL) >> (sizeof(word_t)*8-BitsLeft))) R |= (CurWord & (~0U >> (32-BitsLeft))) << BitsInCurWord;
<< BitsInCurWord);
// BitsLeft bits have just been used up from CurWord. BitsLeft is in the // BitsLeft bits have just been used up from CurWord.
// range [1..32]/[1..64] so be careful how we shift. if (BitsLeft != 32)
if (BitsLeft != sizeof(word_t)*8)
CurWord >>= BitsLeft; CurWord >>= BitsLeft;
else else
CurWord = 0; CurWord = 0;
BitsInCurWord = sizeof(word_t)*8-BitsLeft; BitsInCurWord = 32-BitsLeft;
return R; return R;
} }
@ -433,21 +416,10 @@ public:
} }
} }
private:
void SkipToFourByteBoundary() { void SkipToFourByteBoundary() {
// If word_t is 64-bits and if we've read less than 32 bits, just dump
// the bits we have up to the next 32-bit boundary.
if (sizeof(word_t) > 4 &&
BitsInCurWord > 32) {
CurWord >>= BitsInCurWord-32;
BitsInCurWord = 32;
return;
}
BitsInCurWord = 0; BitsInCurWord = 0;
CurWord = 0; CurWord = 0;
} }
public:
unsigned ReadCode() { unsigned ReadCode() {
return Read(CurCodeSize); return Read(CurCodeSize);
@ -471,15 +443,15 @@ public:
// don't care what code widths are used inside of it. // don't care what code widths are used inside of it.
ReadVBR(bitc::CodeLenWidth); ReadVBR(bitc::CodeLenWidth);
SkipToFourByteBoundary(); SkipToFourByteBoundary();
unsigned NumFourBytes = Read(bitc::BlockSizeWidth); unsigned NumWords = Read(bitc::BlockSizeWidth);
// Check that the block wasn't partially defined, and that the offset isn't // Check that the block wasn't partially defined, and that the offset isn't
// bogus. // bogus.
size_t SkipTo = GetCurrentBitNo() + NumFourBytes*4*8; size_t SkipTo = NextChar + NumWords*4;
if (AtEndOfStream() || !canSkipToPos(SkipTo/8)) if (AtEndOfStream() || !canSkipToPos(SkipTo))
return true; return true;
JumpToBit(SkipTo); NextChar = SkipTo;
return false; return false;
} }