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Fix a heinous inefficiency introduced in r149918, wherein reading each byte of a

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BLOB (i.e., large, performance intensive data) in a bitcode file was switched to
invoking one virtual method call per byte read.  Now we do one virtual call per
BLOB.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173065 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2013-01-21 18:24:49 +00:00
parent afe77f33b2
commit 69582cf6c4
2 changed files with 8 additions and 15 deletions
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6
include/llvm/Bitcode/BitstreamReader.h
View File

@ -237,12 +237,6 @@ public:
static_cast<uint64_t>(pos - 1)); static_cast<uint64_t>(pos - 1));
} }
unsigned char getByte(size_t pos) {
uint8_t byte = -1;
BitStream->getBitcodeBytes().readByte(pos, &byte);
return byte;
}
uint32_t getWord(size_t pos) { uint32_t getWord(size_t pos) {
uint8_t buf[4] = { 0xFF, 0xFF, 0xFF, 0xFF }; uint8_t buf[4] = { 0xFF, 0xFF, 0xFF, 0xFF };
BitStream->getBitcodeBytes().readBytes(pos, sizeof(buf), buf, NULL); BitStream->getBitcodeBytes().readBytes(pos, sizeof(buf), buf, NULL);

17
lib/Bitcode/Reader/BitstreamReader.cpp
View File

@ -255,18 +255,17 @@ unsigned BitstreamCursor::readRecord(unsigned AbbrevID,
break; break;
} }
// Otherwise, read the number of bytes. If we can return a reference to // Otherwise, inform the streamer that we need these bytes in memory.
// the data, do so to avoid copying it. const char *Ptr = (const char*)
BitStream->getBitcodeBytes().getPointer(CurBitPos/8, NumElts);
// If we can return a reference to the data, do so to avoid copying it.
if (Blob) { if (Blob) {
*Blob = *Blob = StringRef(Ptr, NumElts);
StringRef((const char*)BitStream->getBitcodeBytes().getPointer(
CurBitPos/8, NumElts),
NumElts);
} else { } else {
// FIXME: This is a brutally inefficient way to do this. Why isn't this // Otherwise, unpack into Vals with zero extension.
// just using getPointer?
for (; NumElts; --NumElts) for (; NumElts; --NumElts)
Vals.push_back(Read(8)); Vals.push_back((unsigned char)*Ptr++);
} }
// Skip over tail padding. // Skip over tail padding.
JumpToBit(NewEnd); JumpToBit(NewEnd);