path: root/lib/Basic/SourceManager.cpp

//===--- SourceManager.cpp - Track and cache source files -----------------===//
//
//                     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 SourceManager interface.
//
//===----------------------------------------------------------------------===//

#include "clang/Basic/SourceManager.h"
#include "clang/Basic/SourceManagerInternals.h"
#include "clang/Basic/FileManager.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/System/Path.h"
#include <algorithm>
using namespace clang;
using namespace SrcMgr;
using llvm::MemoryBuffer;

//===----------------------------------------------------------------------===//
// SourceManager Helper Classes
//===----------------------------------------------------------------------===//

ContentCache::~ContentCache() {
  delete Buffer;
}

/// getSizeBytesMapped - Returns the number of bytes actually mapped for
///  this ContentCache.  This can be 0 if the MemBuffer was not actually
///  instantiated.
unsigned ContentCache::getSizeBytesMapped() const {
  return Buffer ? Buffer->getBufferSize() : 0;
}

/// getSize - Returns the size of the content encapsulated by this ContentCache.
///  This can be the size of the source file or the size of an arbitrary
///  scratch buffer.  If the ContentCache encapsulates a source file, that
///  file is not lazily brought in from disk to satisfy this query.
unsigned ContentCache::getSize() const {
  return Buffer ? (unsigned) Buffer->getBufferSize()
                : (unsigned) Entry->getSize();
}

void ContentCache::replaceBuffer(const llvm::MemoryBuffer *B) {
  assert(B != Buffer);
  
  delete Buffer;
  Buffer = B;
}

const llvm::MemoryBuffer *ContentCache::getBuffer(std::string *ErrorStr) const {
  // Lazily create the Buffer for ContentCaches that wrap files.
  if (!Buffer && Entry) {
    Buffer = MemoryBuffer::getFile(Entry->getName(), ErrorStr,Entry->getSize());

    // If we were unable to open the file, then we are in an inconsistent
    // situation where the content cache referenced a file which no longer
    // exists. Most likely, we were using a stat cache with an invalid entry but
    // the file could also have been removed during processing. Since we can't
    // really deal with this situation, just create an empty buffer.
    //
    // FIXME: This is definitely not ideal, but our immediate clients can't
    // currently handle returning a null entry here. Ideally we should detect
    // that we are in an inconsistent situation and error out as quickly as
    // possible.
    if (!Buffer) {
      const llvm::StringRef FillStr("<<<MISSING SOURCE FILE>>>\n");
      Buffer = MemoryBuffer::getNewMemBuffer(Entry->getSize(), "<invalid>");
      char *Ptr = const_cast<char*>(Buffer->getBufferStart());
      for (unsigned i = 0, e = Entry->getSize(); i != e; ++i)
        Ptr[i] = FillStr[i % FillStr.size()];
    }
  }
  return Buffer;
}

unsigned LineTableInfo::getLineTableFilenameID(const char *Ptr, unsigned Len) {
  // Look up the filename in the string table, returning the pre-existing value
  // if it exists.
  llvm::StringMapEntry<unsigned> &Entry =
    FilenameIDs.GetOrCreateValue(Ptr, Ptr+Len, ~0U);
  if (Entry.getValue() != ~0U)
    return Entry.getValue();

  // Otherwise, assign this the next available ID.
  Entry.setValue(FilenamesByID.size());
  FilenamesByID.push_back(&Entry);
  return FilenamesByID.size()-1;
}

/// AddLineNote - Add a line note to the line table that indicates that there
/// is a #line at the specified FID/Offset location which changes the presumed
/// location to LineNo/FilenameID.
void LineTableInfo::AddLineNote(unsigned FID, unsigned Offset,
                                unsigned LineNo, int FilenameID) {
  std::vector<LineEntry> &Entries = LineEntries[FID];

  assert((Entries.empty() || Entries.back().FileOffset < Offset) &&
         "Adding line entries out of order!");

  SrcMgr::CharacteristicKind Kind = SrcMgr::C_User;
  unsigned IncludeOffset = 0;

  if (!Entries.