First round of dead file removal

obsolete/breakpad/common/dwarf_line_to_module.h

-// -*- mode: c++ -*-
-
-// Copyright (c) 2010 Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-// Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
-
-// The DwarfLineToModule class accepts line number information from a
-// DWARF parser and adds it to a google_breakpad::Module. The Module
-// can write that data out as a Breakpad symbol file.
-
-#ifndef COMMON_LINUX_DWARF_LINE_TO_MODULE_H
-#define COMMON_LINUX_DWARF_LINE_TO_MODULE_H
-
-#include "common/module.h"
-#include "common/dwarf/dwarf2reader.h"
-
-namespace google_breakpad {
-
-// A class for producing a vector of google_breakpad::Module::Line
-// instances from parsed DWARF line number data.  
-//
-// An instance of this class can be provided as a handler to a
-// dwarf2reader::LineInfo DWARF line number information parser. The
-// handler accepts source location information from the parser and
-// uses it to produce a vector of google_breakpad::Module::Line
-// objects, referring to google_breakpad::Module::File objects added
-// to a particular google_breakpad::Module.
-//
-// GNU toolchain omitted sections support:
-// ======================================
-//
-// Given the right options, the GNU toolchain will omit unreferenced
-// functions from the final executable. Unfortunately, when it does so, it
-// does not remove the associated portions of the DWARF line number
-// program; instead, it gives the DW_LNE_set_address instructions referring
-// to the now-deleted code addresses of zero. Given this input, the DWARF
-// line parser will call AddLine with a series of lines starting at address
-// zero. For example, here is the output from 'readelf -wl' for a program
-// with four functions, the first three of which have been omitted:
-//
-//   Line Number Statements:
-//    Extended opcode 2: set Address to 0x0
-//    Advance Line by 14 to 15
-//    Copy
-//    Special opcode 48: advance Address by 3 to 0x3 and Line by 1 to 16
-//    Special opcode 119: advance Address by 8 to 0xb and Line by 2 to 18
-//    Advance PC by 2 to 0xd
-//    Extended opcode 1: End of Sequence
-// 
-//    Extended opcode 2: set Address to 0x0
-//    Advance Line by 14 to 15
-//    Copy
-//    Special opcode 48: advance Address by 3 to 0x3 and Line by 1 to 16
-//    Special opcode 119: advance Address by 8 to 0xb and Line by 2 to 18
-//    Advance PC by 2 to 0xd
-//    Extended opcode 1: End of Sequence
-// 
-//    Extended opcode 2: set Address to 0x0
-//    Advance Line by 19 to 20
-//    Copy
-//    Special opcode 48: advance Address by 3 to 0x3 and Line by 1 to 21
-//    Special opcode 76: advance Address by 5 to 0x8 and Line by 1 to 22
-//    Advance PC by 2 to 0xa
-//    Extended opcode 1: End of Sequence
-// 
-//    Extended opcode 2: set Address to 0x80483a4
-//    Advance Line by 23 to 24
-//    Copy
-//    Special opcode 202: advance Address by 14 to 0x80483b2 and Line by 1 to 25
-//    Special opcode 76: advance Address by 5 to 0x80483b7 and Line by 1 to 26
-//    Advance PC by 6 to 0x80483bd
-//    Extended opcode 1: End of Sequence
-//
-// Instead of collecting runs of lines describing code that is not there,
-// we try to recognize and drop them. Since the linker doesn't explicitly
-// distinguish references to dropped sections from genuine references to
-// code at address zero, we must use a heuristic. We have chosen:
-//
-// - If a line starts at address zero, omit it. (On the platforms
-//   breakpad targets, it is extremely unlikely that there will be code
-//   at address zero.)
-//
-// - If a line starts immediately after an omitted line, omit it too.
-class DwarfLineToModule: public dwarf2reader::LineInfoHandler {
- public:
-  // As the DWARF line info parser passes us line records, add source
-  // files to MODULE, and add all lines to the end of LINES. LINES
-  // need not be empty. If the parser hands us a zero-length line, we
-  // omit it. If the parser hands us a line that extends beyond the
-  // end of the address space, we clip it. It's up to our client to
-  // sort out which lines belong to which functions; we don't add them
-  // to any particular function in MODULE ourselves.
-  DwarfLineToModule(Module *module, vector<Module::Line> *lines)
-      : module_(module),
-        lines_(lines),
-        highest_file_number_(-1),
-        omitted_line_end_(0),
-        warned_bad_file_number_(false),
-        warned_bad_directory_number_(false) { }
-  
-  ~DwarfLineToModule() { }
-
-  void DefineDir(const std::string &name, uint32 dir_num);
-  void DefineFile(const std::string &name, int32 file_num,
-                  uint32 dir_num, uint64 mod_time,
-                  uint64 length);
-  void AddLine(uint64 address, uint64 length,
-               uint32 file_num, uint32 line_num, uint32 column_num);
-
- private:
-
-  typedef std::map<uint32, std::string> DirectoryTable;
-  typedef std::map<uint32, Module::File *> FileTable;
-
-  // The module we're contributing debugging info to. Owned by our
-  // client.
-  Module *module_;
-
-  // The vector of lines we're accumulating. Owned by our client.
-  //
-  // In a Module, as in a breakpad symbol file, lines belong to
-  // specific functions, but DWARF simply assigns lines to addresses;
-  // one must infer the line/function relationship using the
-  // functions' beginning and ending addresses. So we can't add these
-  // to the appropriate function from module_ until we've read the
-  // function info as well. Instead, we accumulate lines here, and let
-  // whoever constructed this sort it all out.
-  vector<Module::Line> *lines_;
-
-  // A table mapping directory numbers to paths.
-  DirectoryTable directories_;
-
-  // A table mapping file numbers to Module::File pointers.
-  FileTable files_;
-
-  // The highest file number we've seen so far, or -1 if we've seen
-  // none.  Used for dynamically defined file numbers.
-  int32 highest_file_number_;
-  
-  // This is the ending address of the last line we omitted, or zero if we
-  // didn't omit the previous line. It is zero before we have received any
-  // AddLine calls.
-  uint64 omitted_line_end_;
-
-  // True if we've warned about:
-  bool warned_bad_file_number_; // bad file numbers
-  bool warned_bad_directory_number_; // bad directory numbers
-};
-
-} // namespace google_breakpad
-
-#endif // COMMON_LINUX_DWARF_LINE_TO_MODULE_H