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/FileManager.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/System/Path.h"
#include "llvm/Bitcode/Serialize.h"
#include "llvm/Bitcode/Deserialize.h"
#include "llvm/Support/Streams.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 Entry ? Entry->getSize() : Buffer->getBufferSize();
}

const llvm::MemoryBuffer *ContentCache::getBuffer() const {  
  // Lazily create the Buffer for ContentCaches that wrap files.
  if (!Buffer && Entry) {
    // FIXME: Should we support a way to not have to do this check over
    //   and over if we cannot open the file?
    Buffer = MemoryBuffer::getFile(Entry->getName(), 0, Entry->getSize());
  }
  return Buffer;
}

//===----------------------------------------------------------------------===//
// Line Table Implementation
//===----------------------------------------------------------------------===//

namespace clang {
struct LineEntry {
  /// FileOffset - The offset in this file that the line entry occurs at.
  unsigned FileOffset;
  
  /// LineNo - The presumed line number of this line entry: #line 4.
  unsigned LineNo;
  
  /// FilenameID - The ID of the filename identified by this line entry:
  /// #line 4 "foo.c".  This is -1 if not specified.
  int FilenameID;
  
  /// Flags - Set the 0 if no flags, 1 if a system header, 
  SrcMgr::CharacteristicKind FileKind;
  
  /// IncludeOffset - This is the offset of the virtual include stack location,
  /// which is manipulated by GNU linemarker directives.  If this is 0 then
  /// there is no virtual #includer.
  unsigned IncludeOffset;
  
  static LineEntry get(unsigned Offs, unsigned Line, int Filename,
                       SrcMgr::CharacteristicKind FileKind,
                       unsigned IncludeOffset) {
    LineEntry E;
    E.FileOffset = Offs;
    E.LineNo = Line;
    E.FilenameID = Filename;
    E.FileKind = FileKind;
    E.IncludeOffset = IncludeOffset;
    return E;
  }
};

// needed for FindNearestLineEntry (upper_bound of LineEntry)
inline bool operator<(const LineEntry &lhs, const LineEntry &rhs) {
  // FIXME: should check the other field?
  return lhs.FileOffset < rhs.FileOffset;
}

inline bool operator<(const LineEntry &E, unsigned Offset) {
  return E.FileOffset < Offset;
}

inline bool operator<(unsigned Offset, const LineEntry &E) {
  return Offset < E.FileOffset;
}
  
/// LineTableInfo - This class is used to hold and unique data used to
/// represent #line information.
class LineTableInfo {
  /// FilenameIDs - This map is used to assign unique IDs to filenames in
  /// #line directives.  This allows us to unique the filenames that
  /// frequently reoccur and reference them with indices.  FilenameIDs holds
  /// the mapping from string -> ID, and FilenamesByID holds the mapping of ID
  /// to string.
  llvm::StringMap<unsigned, llvm::BumpPtrAllocator> FilenameIDs;
  std::vector<llvm::StringMapEntry<unsigned>*> FilenamesByID;
  
  /// LineEntries - This is a map from FileIDs to a list of line entries (sorted
  /// by the offset they occur in the file.
  std::map<unsigned, std::vector<LineEntry> > LineEntries;
public:
  LineTableInfo() {
  }
  
  void clear() {
    FilenameIDs.clear();
    FilenamesByID.clear();
  }
  
  ~LineTableInfo() {}
  
  unsigned getLineTableFilenameID(const char *Ptr, unsigned Len);
  const char *getFilename(unsigned ID) const {
    assert(ID < FilenamesByID.size() && "Invalid FilenameID");
    return FilenamesByID[ID]->getKeyData();
  }
  
  void AddLineNote(unsigned FID, unsigned Offset,
                   unsigned LineNo, int FilenameID);
  void AddLineNote(unsigned FID, unsigned Offset,
                   unsigned LineNo