72 lines
2.7 KiB
C++
72 lines
2.7 KiB
C++
//===--- ScratchBuffer.cpp - Scratch space for forming tokens -------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the ScratchBuffer interface.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "clang/Lex/ScratchBuffer.h"
|
|
#include "clang/Basic/SourceManager.h"
|
|
#include "llvm/Support/MemoryBuffer.h"
|
|
using namespace clang;
|
|
|
|
// ScratchBufSize - The size of each chunk of scratch memory. Slightly less
|
|
//than a page, almost certainly enough for anything. :)
|
|
static const unsigned ScratchBufSize = 4060;
|
|
|
|
ScratchBuffer::ScratchBuffer(SourceManager &SM) : SourceMgr(SM), CurBuffer(0) {
|
|
// Set BytesUsed so that the first call to getToken will require an alloc.
|
|
BytesUsed = ScratchBufSize;
|
|
FileID = 0;
|
|
}
|
|
|
|
/// getToken - Splat the specified text into a temporary MemoryBuffer and
|
|
/// return a SourceLocation that refers to the token. This is just like the
|
|
/// method below, but returns a location that indicates the physloc of the
|
|
/// token.
|
|
SourceLocation ScratchBuffer::getToken(const char *Buf, unsigned Len) {
|
|
if (BytesUsed+Len > ScratchBufSize)
|
|
AllocScratchBuffer(Len);
|
|
|
|
// Copy the token data into the buffer.
|
|
memcpy(CurBuffer+BytesUsed, Buf, Len);
|
|
|
|
// Remember that we used these bytes.
|
|
BytesUsed += Len;
|
|
|
|
assert(BytesUsed-Len < (1 << SourceLocation::FilePosBits) &&
|
|
"Out of range file position!");
|
|
|
|
return SourceLocation::getFileLoc(FileID, BytesUsed-Len);
|
|
}
|
|
|
|
|
|
/// getToken - Splat the specified text into a temporary MemoryBuffer and
|
|
/// return a SourceLocation that refers to the token. The SourceLoc value
|
|
/// gives a virtual location that the token will appear to be from.
|
|
SourceLocation ScratchBuffer::getToken(const char *Buf, unsigned Len,
|
|
SourceLocation SourceLoc) {
|
|
// Map the physloc to the specified sourceloc.
|
|
return SourceMgr.getInstantiationLoc(getToken(Buf, Len), SourceLoc);
|
|
}
|
|
|
|
void ScratchBuffer::AllocScratchBuffer(unsigned RequestLen) {
|
|
// Only pay attention to the requested length if it is larger than our default
|
|
// page size. If it is, we allocate an entire chunk for it. This is to
|
|
// support gigantic tokens, which almost certainly won't happen. :)
|
|
if (RequestLen < ScratchBufSize)
|
|
RequestLen = ScratchBufSize;
|
|
|
|
llvm::MemoryBuffer *Buf =
|
|
llvm::MemoryBuffer::getNewMemBuffer(RequestLen, "<scratch space>");
|
|
FileID = SourceMgr.createFileIDForMemBuffer(Buf);
|
|
CurBuffer = const_cast<char*>(Buf->getBufferStart());
|
|
BytesUsed = 0;
|
|
}
|