LCOV - code coverage report
Current view: directory - toolkit/crashreporter/google-breakpad/src/common - stabs_reader.h (source / functions) Found Hit Coverage
Test: app.info Lines: 13 0 0.0 %
Date: 2012-06-02 Functions: 11 0 0.0 %

       1                 : // -*- mode: c++ -*-
       2                 : 
       3                 : // Copyright (c) 2010 Google Inc. All Rights Reserved.
       4                 : //
       5                 : // Redistribution and use in source and binary forms, with or without
       6                 : // modification, are permitted provided that the following conditions are
       7                 : // met:
       8                 : //
       9                 : //     * Redistributions of source code must retain the above copyright
      10                 : // notice, this list of conditions and the following disclaimer.
      11                 : //     * Redistributions in binary form must reproduce the above
      12                 : // copyright notice, this list of conditions and the following disclaimer
      13                 : // in the documentation and/or other materials provided with the
      14                 : // distribution.
      15                 : //     * Neither the name of Google Inc. nor the names of its
      16                 : // contributors may be used to endorse or promote products derived from
      17                 : // this software without specific prior written permission.
      18                 : //
      19                 : // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      20                 : // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      21                 : // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      22                 : // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      23                 : // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      24                 : // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      25                 : // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      26                 : // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      27                 : // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      28                 : // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      29                 : // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      30                 : 
      31                 : // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
      32                 : 
      33                 : // stabs_reader.h: Define StabsReader, a parser for STABS debugging
      34                 : // information. A description of the STABS debugging format can be
      35                 : // found at:
      36                 : //
      37                 : //    http://sourceware.org/gdb/current/onlinedocs/stabs_toc.html
      38                 : //
      39                 : // The comments here assume you understand the format.
      40                 : //
      41                 : // This parser can handle big-endian and little-endian data, and the symbol
      42                 : // values may be either 32 or 64 bits long. It handles both STABS in
      43                 : // sections (as used on Linux) and STABS appearing directly in an
      44                 : // a.out-like symbol table (as used in Darwin OS X Mach-O files).
      45                 : 
      46                 : #ifndef COMMON_STABS_READER_H__
      47                 : #define COMMON_STABS_READER_H__
      48                 : 
      49                 : #include <stddef.h>
      50                 : #include <stdint.h>
      51                 : 
      52                 : #ifdef HAVE_A_OUT_H
      53                 : #include <a.out.h>
      54                 : #endif
      55                 : #ifdef HAVE_MACH_O_NLIST_H
      56                 : #include <mach-o/nlist.h>
      57                 : #endif
      58                 : 
      59                 : #include <string>
      60                 : #include <vector>
      61                 : 
      62                 : #include "common/byte_cursor.h"
      63                 : 
      64                 : namespace google_breakpad {
      65                 : 
      66                 : class StabsHandler;
      67                 : 
      68               0 : class StabsReader {
      69                 :  public:
      70                 :   // Create a reader for the STABS debug information whose .stab section is
      71                 :   // being traversed by ITERATOR, and whose .stabstr section is referred to
      72                 :   // by STRINGS. The reader will call the member functions of HANDLER to
      73                 :   // report the information it finds, when the reader's 'Process' member
      74                 :   // function is called.
      75                 :   //
      76                 :   // BIG_ENDIAN should be true if the entries in the .stab section are in
      77                 :   // big-endian form, or false if they are in little-endian form.
      78                 :   //
      79                 :   // VALUE_SIZE should be either 4 or 8, indicating the size of the 'value'
      80                 :   // field in each entry in bytes.
      81                 :   //
      82                 :   // UNITIZED should be true if the STABS data is stored in units with
      83                 :   // N_UNDF headers. This is usually the case for STABS stored in sections,
      84                 :   // like .stab/.stabstr, and usually not the case for STABS stored in the
      85                 :   // actual symbol table; UNITIZED should be true when parsing Linux stabs,
      86                 :   // false when parsing Mac OS X STABS. For details, see:
      87                 :   // http://sourceware.org/gdb/current/onlinedocs/stabs/Stab-Section-Basics.html
      88                 :   // 
      89                 :   // Note that, in ELF, the .stabstr section should be found using the
      90                 :   // 'sh_link' field of the .stab section header, not by name.
      91                 :   StabsReader(const uint8_t *stab,    size_t stab_size,
      92                 :               const uint8_t *stabstr, size_t stabstr_size,
      93                 :               bool big_endian, size_t value_size, bool unitized,
      94                 :               StabsHandler *handler);
      95                 : 
      96                 :   // Process the STABS data, calling the handler's member functions to
      97                 :   // report what we find.  While the handler functions return true,
      98                 :   // continue to process until we reach the end of the section.  If we
      99                 :   // processed the entire section and all handlers returned true,
     100                 :   // return true.  If any handler returned false, return false.
     101                 :   // 
     102                 :   // This is only meant to be called once per StabsReader instance;
     103                 :   // resuming a prior processing pass that stopped abruptly isn't supported.
     104                 :   bool Process();
     105                 : 
     106                 :  private:
     107                 : 
     108                 :   // An class for walking arrays of STABS entries. This isolates the main
     109                 :   // STABS reader from the exact format (size; endianness) of the entries
     110                 :   // themselves.
     111                 :   class EntryIterator {
     112                 :    public:
     113                 :     // The contents of a STABS entry, adjusted for the host's endianness,
     114                 :     // word size, 'struct nlist' layout, and so on.
     115                 :     struct Entry {
     116                 :       // True if this iterator has reached the end of the entry array. When
     117                 :       // this is set, the other members of this structure are not valid.
     118                 :       bool at_end;
     119                 : 
     120                 :       // The number of this entry within the list.
     121                 :       size_t index;
     122                 : 
     123                 :       // The current entry's name offset. This is the offset within the
     124                 :       // current compilation unit's strings, as establish by the N_UNDF entries.
     125                 :       size_t name_offset;
     126                 : 
     127                 :       // The current entry's type, 'other' field, descriptor, and value.
     128                 :       unsigned char type;
     129                 :       unsigned char other;
     130                 :       short descriptor;
     131                 :       uint64_t value;
     132                 :     };
     133                 : 
     134                 :     // Create a EntryIterator walking the entries in BUFFER. Treat the
     135                 :     // entries as big-endian if BIG_ENDIAN is true, as little-endian
     136                 :     // otherwise. Assume each entry has a 'value' field whose size is
     137                 :     // VALUE_SIZE.
     138                 :     //
     139                 :     // This would not be terribly clean to extend to other format variations,
     140                 :     // but it's enough to handle Linux and Mac, and we'd like STABS to die
     141                 :     // anyway.
     142                 :     //
     143                 :     // For the record: on Linux, STABS entry values are always 32 bits,
     144                 :     // regardless of the architecture address size (don't ask me why); on
     145                 :     // Mac, they are 32 or 64 bits long. Oddly, the section header's entry
     146                 :     // size for a Linux ELF .stab section varies according to the ELF class
     147                 :     // from 12 to 20 even as the actual entries remain unchanged.
     148                 :     EntryIterator(const ByteBuffer *buffer, bool big_endian, size_t value_size);
     149                 : 
     150                 :     // Move to the next entry. This function's behavior is undefined if
     151                 :     // at_end() is true when it is called.
     152               0 :     EntryIterator &operator++() { Fetch(); entry_.index++; return *this; }
     153                 : 
     154                 :     // Dereferencing this iterator produces a reference to an Entry structure
     155                 :     // that holds the current entry's values. The entry is owned by this
     156                 :     // EntryIterator, and will be invalidated at the next call to operator++.
     157                 :     const Entry &operator*() const { return entry_; }
     158               0 :     const Entry *operator->() const { return &entry_; }
     159                 : 
     160                 :    private:
     161                 :     // Read the STABS entry at cursor_, and set entry_ appropriately.
     162                 :     void Fetch();
     163                 : 
     164                 :     // The size of entries' value field, in bytes.
     165                 :     size_t value_size_;
     166                 : 
     167                 :     // A byte cursor traversing buffer_.
     168                 :     ByteCursor cursor_;
     169                 : 
     170                 :     // Values for the entry this iterator refers to.
     171                 :     Entry entry_;
     172                 :   };
     173                 : 
     174                 :   // A source line, saved to be reported later.
     175                 :   struct Line {
     176                 :     uint64_t address;
     177                 :     const char *filename;
     178                 :     int number;
     179                 :   };
     180                 : 
     181                 :   // Return the name of the current symbol.
     182                 :   const char *SymbolString();
     183                 : 
     184                 :   // Process a compilation unit starting at symbol_.  Return true
     185                 :   // to continue processing, or false to abort.
     186                 :   bool ProcessCompilationUnit();
     187                 : 
     188                 :   // Process a function in current_source_file_ starting at symbol_.
     189                 :   // Return true to continue processing, or false to abort.
     190                 :   bool ProcessFunction();
     191                 : 
     192                 :   // The STABS entries we're parsing.
     193                 :   ByteBuffer entries_;
     194                 : 
     195                 :   // The string section to which the entries refer.
     196                 :   ByteBuffer strings_;
     197                 : 
     198                 :   // The iterator walking the STABS entries.
     199                 :   EntryIterator iterator_;
     200                 : 
     201                 :   // True if the data is "unitized"; see the explanation in the comment for
     202                 :   // StabsReader::StabsReader.
     203                 :   bool unitized_;
     204                 : 
     205                 :   StabsHandler *handler_;
     206                 : 
     207                 :   // The offset of the current compilation unit's strings within stabstr_.
     208                 :   size_t string_offset_;
     209                 : 
     210                 :   // The value string_offset_ should have for the next compilation unit,
     211                 :   // as established by N_UNDF entries.
     212                 :   size_t next_cu_string_offset_;
     213                 : 
     214                 :   // The current source file name.
     215                 :   const char *current_source_file_;
     216                 : 
     217                 :   // Mac OS X STABS place SLINE records before functions; we accumulate a
     218                 :   // vector of these until we see the FUN record, and then report them
     219                 :   // after the StartFunction call.
     220                 :   std::vector<Line> queued_lines_;
     221                 : };
     222                 : 
     223                 : // Consumer-provided callback structure for the STABS reader.  Clients
     224                 : // of the STABS reader provide an instance of this structure.  The
     225                 : // reader then invokes the member functions of that instance to report
     226                 : // the information it finds.
     227                 : //
     228                 : // The default definitions of the member functions do nothing, and return
     229                 : // true so processing will continue.
     230                 : class StabsHandler {
     231                 :  public:
     232               0 :   StabsHandler() { }
     233               0 :   virtual ~StabsHandler() { }
     234                 : 
     235                 :   // Some general notes about the handler callback functions:
     236                 : 
     237                 :   // Processing proceeds until the end of the .stabs section, or until
     238                 :   // one of these functions returns false.
     239                 : 
     240                 :   // The addresses given are as reported in the STABS info, without
     241                 :   // regard for whether the module may be loaded at different
     242                 :   // addresses at different times (a shared library, say).  When
     243                 :   // processing STABS from an ELF shared library, the addresses given
     244                 :   // all assume the library is loaded at its nominal load address.
     245                 :   // They are *not* offsets from the nominal load address.  If you
     246                 :   // want offsets, you must subtract off the library's nominal load
     247                 :   // address.
     248                 : 
     249                 :   // The arguments to these functions named FILENAME are all
     250                 :   // references to strings stored in the .stabstr section.  Because
     251                 :   // both the Linux and Solaris linkers factor out duplicate strings
     252                 :   // from the .stabstr section, the consumer can assume that if two
     253                 :   // FILENAME values are different addresses, they represent different
     254                 :   // file names.
     255                 :   //
     256                 :   // Thus, it's safe to use (say) std::map<char *, ...>, which does
     257                 :   // string address comparisons, not string content comparisons.
     258                 :   // Since all the strings are in same array of characters --- the
     259                 :   // .stabstr section --- comparing their addresses produces
     260                 :   // predictable, if not lexicographically meaningful, results.
     261                 : 
     262                 :   // Begin processing a compilation unit whose main source file is
     263                 :   // named FILENAME, and whose base address is ADDRESS.  If
     264                 :   // BUILD_DIRECTORY is non-NULL, it is the name of the build
     265                 :   // directory in which the compilation occurred.
     266               0 :   virtual bool StartCompilationUnit(const char *filename, uint64_t address,
     267                 :                                     const char *build_directory) {
     268               0 :     return true;
     269                 :   }
     270                 : 
     271                 :   // Finish processing the compilation unit.  If ADDRESS is non-zero,
     272                 :   // it is the ending address of the compilation unit.  If ADDRESS is
     273                 :   // zero, then the compilation unit's ending address is not
     274                 :   // available, and the consumer must infer it by other means.
     275               0 :   virtual bool EndCompilationUnit(uint64_t address) { return true; }
     276                 : 
     277                 :   // Begin processing a function named NAME, whose starting address is
     278                 :   // ADDRESS.  This function belongs to the compilation unit that was
     279                 :   // most recently started but not ended.
     280                 :   //
     281                 :   // Note that, unlike filenames, NAME is not a pointer into the
     282                 :   // .stabstr section; this is because the name as it appears in the
     283                 :   // STABS data is followed by type information.  The value passed to
     284                 :   // StartFunction is the function name alone.
     285                 :   //
     286                 :   // In languages that use name mangling, like C++, NAME is mangled.
     287               0 :   virtual bool StartFunction(const std::string &name, uint64_t address) {
     288               0 :     return true;
     289                 :   }
     290                 : 
     291                 :   // Finish processing the function.  If ADDRESS is non-zero, it is
     292                 :   // the ending address for the function.  If ADDRESS is zero, then
     293                 :   // the function's ending address is not available, and the consumer
     294                 :   // must infer it by other means.
     295               0 :   virtual bool EndFunction(uint64_t address) { return true; }
     296                 :   
     297                 :   // Report that the code at ADDRESS is attributable to line NUMBER of
     298                 :   // the source file named FILENAME.  The caller must infer the ending
     299                 :   // address of the line.
     300               0 :   virtual bool Line(uint64_t address, const char *filename, int number) {
     301               0 :     return true;
     302                 :   }
     303                 : 
     304                 :   // Report a warning.  FORMAT is a printf-like format string,
     305                 :   // specifying how to format the subsequent arguments.
     306                 :   virtual void Warning(const char *format, ...) = 0;
     307                 : };
     308                 : 
     309                 : } // namespace google_breakpad
     310                 : 
     311                 : #endif  // COMMON_STABS_READER_H__

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