You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
84 lines
3.2 KiB
84 lines
3.2 KiB
//===--- ScratchBuffer.cpp - Scratch space for forming tokens -------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the ScratchBuffer interface.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "clang/Lex/ScratchBuffer.h"
|
|
#include "clang/Basic/SourceManager.h"
|
|
#include "llvm/Support/MemoryBuffer.h"
|
|
#include <cstring>
|
|
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(nullptr) {
|
|
// Set BytesUsed so that the first call to getToken will require an alloc.
|
|
BytesUsed = ScratchBufSize;
|
|
}
|
|
|
|
/// 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,
|
|
const char *&DestPtr) {
|
|
if (BytesUsed+Len+2 > ScratchBufSize)
|
|
AllocScratchBuffer(Len+2);
|
|
else {
|
|
// Clear out the source line cache if it's already been computed.
|
|
// FIXME: Allow this to be incrementally extended.
|
|
SourceMgr.getSLocEntry(SourceMgr.getFileID(BufferStartLoc))
|
|
.getFile()
|
|
.getContentCache()
|
|
.SourceLineCache = SrcMgr::LineOffsetMapping();
|
|
}
|
|
|
|
// Prefix the token with a \n, so that it looks like it is the first thing on
|
|
// its own virtual line in caret diagnostics.
|
|
CurBuffer[BytesUsed++] = '\n';
|
|
|
|
// Return a pointer to the character data.
|
|
DestPtr = CurBuffer+BytesUsed;
|
|
|
|
// Copy the token data into the buffer.
|
|
memcpy(CurBuffer+BytesUsed, Buf, Len);
|
|
|
|
// Remember that we used these bytes.
|
|
BytesUsed += Len+1;
|
|
|
|
// Add a NUL terminator to the token. This keeps the tokens separated, in
|
|
// case they get relexed, and puts them on their own virtual lines in case a
|
|
// diagnostic points to one.
|
|
CurBuffer[BytesUsed-1] = '\0';
|
|
|
|
return BufferStartLoc.getLocWithOffset(BytesUsed-Len-1);
|
|
}
|
|
|
|
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;
|
|
|
|
// Get scratch buffer. Zero-initialize it so it can be dumped into a PCH file
|
|
// deterministically.
|
|
std::unique_ptr<llvm::WritableMemoryBuffer> OwnBuf =
|
|
llvm::WritableMemoryBuffer::getNewMemBuffer(RequestLen,
|
|
"<scratch space>");
|
|
CurBuffer = OwnBuf->getBufferStart();
|
|
FileID FID = SourceMgr.createFileID(std::move(OwnBuf));
|
|
BufferStartLoc = SourceMgr.getLocForStartOfFile(FID);
|
|
BytesUsed = 0;
|
|
}
|