From 69582cf6c46456ad542df5aa09c47700c9525645 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Mon, 21 Jan 2013 18:24:49 +0000 Subject: [PATCH] Fix a heinous inefficiency introduced in r149918, wherein reading each byte of a 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 --- include/llvm/Bitcode/BitstreamReader.h | 6 ------ lib/Bitcode/Reader/BitstreamReader.cpp | 17 ++++++++--------- 2 files changed, 8 insertions(+), 15 deletions(-) diff --git a/include/llvm/Bitcode/BitstreamReader.h b/include/llvm/Bitcode/BitstreamReader.h index 16f9686a93c..c143886b2cd 100644 --- a/include/llvm/Bitcode/BitstreamReader.h +++ b/include/llvm/Bitcode/BitstreamReader.h @@ -237,12 +237,6 @@ public: static_cast(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) { uint8_t buf[4] = { 0xFF, 0xFF, 0xFF, 0xFF }; BitStream->getBitcodeBytes().readBytes(pos, sizeof(buf), buf, NULL); diff --git a/lib/Bitcode/Reader/BitstreamReader.cpp b/lib/Bitcode/Reader/BitstreamReader.cpp index 92133bb969c..7984512b4b2 100644 --- a/lib/Bitcode/Reader/BitstreamReader.cpp +++ b/lib/Bitcode/Reader/BitstreamReader.cpp @@ -255,18 +255,17 @@ unsigned BitstreamCursor::readRecord(unsigned AbbrevID, break; } - // Otherwise, read the number of bytes. If we can return a reference to - // the data, do so to avoid copying it. + // Otherwise, inform the streamer that we need these bytes in memory. + 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) { - *Blob = - StringRef((const char*)BitStream->getBitcodeBytes().getPointer( - CurBitPos/8, NumElts), - NumElts); + *Blob = StringRef(Ptr, NumElts); } else { - // FIXME: This is a brutally inefficient way to do this. Why isn't this - // just using getPointer? + // Otherwise, unpack into Vals with zero extension. for (; NumElts; --NumElts) - Vals.push_back(Read(8)); + Vals.push_back((unsigned char)*Ptr++); } // Skip over tail padding. JumpToBit(NewEnd);