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/System/Path.h"
#include "llvm/Support/Streams.h"
#include <algorithm>
#include <iostream>
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;
}

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.empty()) {
    // If this is a '#line 4' after '#line 42 "foo.h"', make sure to remember
    // that we are still in "foo.h".
    if (FilenameID == -1)
      FilenameID = Entries.back().FilenameID;
    
    // If we are after a line marker that switched us to system header mode, or
    // that set #include information, preserve it.
    Kind = Entries.back().FileKind;
    IncludeOffset = Entries.back().IncludeOffset;
  }
  
  Entries.push_back(LineEntry::get(Offset, LineNo, FilenameID, Kind,
                                   IncludeOffset));
}

/// AddLineNote This is the same as the previous version of AddLineNote, but is
/// used for GNU line markers.  If EntryExit is 0, then this doesn't change the
/// presumed #include stack.  If it is 1, this is a file entry, if it is 2 then
/// this is a file exit.  FileKind specifies whether this is a system header or
/// extern C system header.
void LineTableInfo::AddLineNote(unsigned FID, unsigned Offset,
                                unsigned LineNo, int FilenameID,
                                unsigned EntryExit,
                                SrcMgr::CharacteristicKind FileKind) {
  assert(FilenameID != -1 && "Unspecified filename should use other accessor");
  
  std::vector<LineEntry> &Entries = LineEntries[FID];
  
  assert((Entries.empty() || Entries.back().FileOffset < Offset) &&
         "Adding line entries out of order!");

  unsigned IncludeOffset = 0;
  if (EntryExit == 0) {  // No #include stack change.
    IncludeOffset = Entries.empty() ? 0 : Entries.back().IncludeOffset;
  } else if (EntryExit ==