Check in LLVM r95781.
diff --git a/lib/Lex/ScratchBuffer.cpp b/lib/Lex/ScratchBuffer.cpp
new file mode 100644
index 0000000..0e98c17
--- /dev/null
+++ b/lib/Lex/ScratchBuffer.cpp
@@ -0,0 +1,73 @@
+//===--- 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"
+#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(0) {
+ // 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);
+
+ // 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.getFileLocWithOffset(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;
+
+ llvm::MemoryBuffer *Buf =
+ llvm::MemoryBuffer::getNewMemBuffer(RequestLen, "<scratch space>");
+ FileID FID = SourceMgr.createFileIDForMemBuffer(Buf);
+ BufferStartLoc = SourceMgr.getLocForStartOfFile(FID);
+ CurBuffer = const_cast<char*>(Buf->getBufferStart());
+ BytesUsed = 1;
+ CurBuffer[0] = '0'; // Start out with a \0 for cleanliness.
+}