Stage two of getting CFE top correct.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@39734 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Lex/ScratchBuffer.cpp b/Lex/ScratchBuffer.cpp
new file mode 100644
index 0000000..12cb096
--- /dev/null
+++ b/Lex/ScratchBuffer.cpp
@@ -0,0 +1,71 @@
+//===--- ScratchBuffer.cpp - Scratch space for forming tokens -------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and 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(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;
+}