zcov: / lib/Lex/ScratchBuffer.cpp


Files: 1 Branches Taken: 75.0% 3 / 4
Generated: 2010-02-10 01:31 Branches Executed: 100.0% 4 / 4
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Programs: 2 Runs 3018


       1                 : //===--- ScratchBuffer.cpp - Scratch space for forming tokens -------------===//
       2                 : //
       3                 : //                     The LLVM Compiler Infrastructure
       4                 : //
       5                 : // This file is distributed under the University of Illinois Open Source
       6                 : // License. See LICENSE.TXT for details.
       7                 : //
       8                 : //===----------------------------------------------------------------------===//
       9                 : //
      10                 : //  This file implements the ScratchBuffer interface.
      11                 : //
      12                 : //===----------------------------------------------------------------------===//
      13                 : 
      14                 : #include "clang/Lex/ScratchBuffer.h"
      15                 : #include "clang/Basic/SourceManager.h"
      16                 : #include "llvm/Support/MemoryBuffer.h"
      17                 : #include <cstring>
      18                 : using namespace clang;
      19                 : 
      20                 : // ScratchBufSize - The size of each chunk of scratch memory.  Slightly less
      21                 : //than a page, almost certainly enough for anything. :)
      22                 : static const unsigned ScratchBufSize = 4060;
      23                 : 
      24             2533: ScratchBuffer::ScratchBuffer(SourceManager &SM) : SourceMgr(SM), CurBuffer(0) {
      25                 :   // Set BytesUsed so that the first call to getToken will require an alloc.
      26             2533:   BytesUsed = ScratchBufSize;
      27             2533: }
      28                 : 
      29                 : /// getToken - Splat the specified text into a temporary MemoryBuffer and
      30                 : /// return a SourceLocation that refers to the token.  This is just like the
      31                 : /// method below, but returns a location that indicates the physloc of the
      32                 : /// token.
      33                 : SourceLocation ScratchBuffer::getToken(const char *Buf, unsigned Len,
      34             2124:                                        const char *&DestPtr) {
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      35             2124:   if (BytesUsed+Len+2 > ScratchBufSize)
      36              131:     AllocScratchBuffer(Len+2);
      37                 : 
      38                 :   // Prefix the token with a \n, so that it looks like it is the first thing on
      39                 :   // its own virtual line in caret diagnostics.
      40             2124:   CurBuffer[BytesUsed++] = '\n';
      41                 : 
      42                 :   // Return a pointer to the character data.
      43             2124:   DestPtr = CurBuffer+BytesUsed;
      44                 : 
      45                 :   // Copy the token data into the buffer.
      46             2124:   memcpy(CurBuffer+BytesUsed, Buf, Len);
      47                 : 
      48                 :   // Remember that we used these bytes.
      49             2124:   BytesUsed += Len+1;
      50                 : 
      51                 :   // Add a NUL terminator to the token.  This keeps the tokens separated, in
      52                 :   // case they get relexed, and puts them on their own virtual lines in case a
      53                 :   // diagnostic points to one.
      54             2124:   CurBuffer[BytesUsed-1] = '\0';
      55                 : 
      56             2124:   return BufferStartLoc.getFileLocWithOffset(BytesUsed-Len-1);
      57                 : }
      58                 : 
      59              131: void ScratchBuffer::AllocScratchBuffer(unsigned RequestLen) {
      60                 :   // Only pay attention to the requested length if it is larger than our default
      61                 :   // page size.  If it is, we allocate an entire chunk for it.  This is to
      62                 :   // support gigantic tokens, which almost certainly won't happen. :)
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      63              131:   if (RequestLen < ScratchBufSize)
      64              131:     RequestLen = ScratchBufSize;
      65                 : 
      66                 :   llvm::MemoryBuffer *Buf =
      67              131:     llvm::MemoryBuffer::getNewMemBuffer(RequestLen, "<scratch space>");
      68              131:   FileID FID = SourceMgr.createFileIDForMemBuffer(Buf);
      69              131:   BufferStartLoc = SourceMgr.getLocForStartOfFile(FID);
      70              131:   CurBuffer = const_cast<char*>(Buf->getBufferStart());
      71              131:   BytesUsed = 1;
      72              131:   CurBuffer[0] = '0';  // Start out with a \0 for cleanliness.
      73              131: }

Generated: 2010-02-10 01:31 by zcov