* Added breakpad support for Linux.

thirdparty/breakpad/common/stabs_reader.h

@@ -0,0 +1,325 @@
+// -*- 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>
+
+// stabs_reader.h: Define StabsReader, a parser for STABS debugging
+// information. A description of the STABS debugging format can be
+// found at:
+//
+//    http://sourceware.org/gdb/current/onlinedocs/stabs_toc.html
+//
+// The comments here assume you understand the format.
+//
+// This parser can handle big-endian and little-endian data, and the symbol
+// values may be either 32 or 64 bits long. It handles both STABS in
+// sections (as used on Linux) and STABS appearing directly in an
+// a.out-like symbol table (as used in Darwin OS X Mach-O files).
+
+#ifndef COMMON_STABS_READER_H__
+#define COMMON_STABS_READER_H__
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#ifdef HAVE_A_OUT_H
+#include <a.out.h>
+#endif
+#ifdef HAVE_MACH_O_NLIST_H
+#include <mach-o/nlist.h>
+#endif
+
+#include <string>
+#include <vector>
+
+#include "common/byte_cursor.h"
+
+namespace google_breakpad {
+
+class StabsHandler;
+
+class StabsReader {
+ public:
+  // Create a reader for the STABS debug information whose .stab section is
+  // being traversed by ITERATOR, and whose .stabstr section is referred to
+  // by STRINGS. The reader will call the member functions of HANDLER to
+  // report the information it finds, when the reader's 'Process' member
+  // function is called.
+  //
+  // BIG_ENDIAN should be true if the entries in the .stab section are in
+  // big-endian form, or false if they are in little-endian form.
+  //
+  // VALUE_SIZE should be either 4 or 8, indicating the size of the 'value'
+  // field in each entry in bytes.
+  //
+  // UNITIZED should be true if the STABS data is stored in units with
+  // N_UNDF headers. This is usually the case for STABS stored in sections,
+  // like .stab/.stabstr, and usually not the case for STABS stored in the
+  // actual symbol table; UNITIZED should be true when parsing Linux stabs,
+  // false when parsing Mac OS X STABS. For details, see:
+  // http://sourceware.org/gdb/current/onlinedocs/stabs/Stab-Section-Basics.html
+  // 
+  // Note that, in ELF, the .stabstr section should be found using the
+  // 'sh_link' field of the .stab section header, not by name.
+  StabsReader(const uint8_t *stab,    size_t stab_size,
+              const uint8_t *stabstr, size_t stabstr_size,
+              bool big_endian, size_t value_size, bool unitized,
+              StabsHandler *handler);
+
+  // Process the STABS data, calling the handler's member functions to
+  // report what we find.  While the handler functions return true,
+  // continue to process until we reach the end of the section.  If we
+  // processed the entire section and all handlers returned true,
+  // return true.  If any handler returned false, return false.
+  // 
+  // This is only meant to be called once per StabsReader instance;
+  // resuming a prior processing pass that stopped abruptly isn't supported.
+  bool Process();
+
+ private:
+
+  // An class for walking arrays of STABS entries. This isolates the main
+  // STABS reader from the exact format (size; endianness) of the entries
+  // themselves.
+  class EntryIterator {
+   public:
+    // The contents of a STABS entry, adjusted for the host's endianness,
+    // word size, 'struct nlist' layout, and so on.
+    struct Entry {
+      // True if this iterator has reached the end of the entry array. When
+      // this is set, the other members of this structure are not valid.
+      bool at_end;
+
+      // The number of this entry within the list.
+      size_t index;
+
+      // The current entry's name offset. This is the offset within the
+      // current compilation unit's strings, as establish by the N_UNDF entries.
+      size_t name_offset;
+
+      // The current entry's type, 'other' field, descriptor, and value.
+      unsigned char type;
+      unsigned char other;
+      short descriptor;
+      uint64_t value;
+    };
+
+    // Create a EntryIterator walking the entries in BUFFER. Treat the
+    // entries as big-endian if BIG_ENDIAN is true, as little-endian
+    // otherwise. Assume each entry has a 'value' field whose size is
+    // VALUE_SIZE.
+    //
+    // This would not be terribly clean to extend to other format variations,
+    // but it's enough to handle Linux and Mac, and we'd like STABS to die
+    // anyway.
+    //
+    // For the record: on Linux, STABS entry values are always 32 bits,
+    // regardless of the architecture address size (don't ask me why); on
+    // Mac, they are 32 or 64 bits long. Oddly, the section header's entry
+    // size for a Linux ELF .stab section varies according to the ELF class
+    // from 12 to 20 even as the actual entries remain unchanged.
+    EntryIterator(const ByteBuffer *buffer, bool big_endian, size_t value_size);
+
+    // Move to the next entry. This function's behavior is undefined if
+    // at_end() is true when it is called.
+    EntryIterator &operator++() { Fetch(); entry_.index++; return *this; }
+
+    // Dereferencing this iterator produces a reference to an Entry structure
+    // that holds the current entry's values. The entry is owned by this
+    // EntryIterator, and will be invalidated at the next call to operator++.
+    const Entry &operator*() const { return entry_; }
+    const Entry *operator->() const { return &entry_; }
+
+   private:
+    // Read the STABS entry at cursor_, and set entry_ appropriately.
+    void Fetch();
+
+    // The size of entries' value field, in bytes.
+    size_t value_size_;
+
+    // A byte cursor traversing buffer_.
+    ByteCursor cursor_;
+
+    // Values for the entry this iterator refers to.
+    Entry entry_;
+  };
+
+  // A source line, saved to be reported later.
+  struct Line {
+    uint64_t address;
+    const char *filename;
+    int number;
+  };
+
+  // Return the name of the current symbol.
+  const char *SymbolString();
+
+  // Process a compilation unit starting at symbol_.  Return true
+  // to continue processing, or false to abort.
+  bool ProcessCompilationUnit();
+
+  // Process a function in current_source_file_ starting at symbol_.
+  // Return true to continue processing, or false to abort.
+  bool ProcessFunction();
+
+  // Process an exported function symbol.
+  // Return true to continue processing, or false to abort.
+  bool ProcessExtern();
+
+  // The STABS entries being parsed.
+  ByteBuffer entries_;
+
+  // The string section to which the entries refer.
+  ByteBuffer strings_;
+
+  // The iterator walking the STABS entries.
+  EntryIterator iterator_;
+
+  // True if the data is "unitized"; see the explanation in the comment for
+  // StabsReader::StabsReader.
+  bool unitized_;
+
+  StabsHandler *handler_;
+
+  // The offset of the current compilation unit's strings within stabstr_.
+  size_t string_offset_;
+
+  // The value string_offset_ should have for the next compilation unit,
+  // as established by N_UNDF entries.
+  size_t next_cu_string_offset_;
+
+  // The current source file name.
+  const char *current_source_file_;
+
+  // Mac OS X STABS place SLINE records before functions; we accumulate a
+  // vector of these until we see the FUN record, and then report them
+  // after the StartFunction call.
+  std::vector<Line> queued_lines_;
+};
+
+// Consumer-provided callback structure for the STABS reader.  Clients
+// of the STABS reader provide an instance of this structure.  The
+// reader then invokes the member functions of that instance to report
+// the information it finds.
+//
+// The default definitions of the member functions do nothing, and return
+// true so processing will continue.
+class StabsHandler {
+ public:
+  StabsHandler() { }
+  virtual ~StabsHandler() { }
+
+  // Some general notes about the handler callback functions:
+
+  // Processing proceeds until the end of the .stabs section, or until
+  // one of these functions returns false.
+
+  // The addresses given are as reported in the STABS info, without
+  // regard for whether the module may be loaded at different
+  // addresses at different times (a shared library, say).  When
+  // processing STABS from an ELF shared library, the addresses given
+  // all assume the library is loaded at its nominal load address.
+  // They are *not* offsets from the nominal load address.  If you
+  // want offsets, you must subtract off the library's nominal load
+  // address.
+
+  // The arguments to these functions named FILENAME are all
+  // references to strings stored in the .stabstr section.  Because
+  // both the Linux and Solaris linkers factor out duplicate strings
+  // from the .stabstr section, the consumer can assume that if two
+  // FILENAME values are different addresses, they represent different
+  // file names.
+  //
+  // Thus, it's safe to use (say) std::map<char *, ...>, which does
+  // string address comparisons, not string content comparisons.
+  // Since all the strings are in same array of characters --- the
+  // .stabstr section --- comparing their addresses produces
+  // predictable, if not lexicographically meaningful, results.
+
+  // Begin processing a compilation unit whose main source file is
+  // named FILENAME, and whose base address is ADDRESS.  If
+  // BUILD_DIRECTORY is non-NULL, it is the name of the build
+  // directory in which the compilation occurred.
+  virtual bool StartCompilationUnit(const char *filename, uint64_t address,
+                                    const char *build_directory) {
+    return true;
+  }
+
+  // Finish processing the compilation unit.  If ADDRESS is non-zero,
+  // it is the ending address of the compilation unit.  If ADDRESS is
+  // zero, then the compilation unit's ending address is not
+  // available, and the consumer must infer it by other means.
+  virtual bool EndCompilationUnit(uint64_t address) { return true; }
+
+  // Begin processing a function named NAME, whose starting address is
+  // ADDRESS.  This function belongs to the compilation unit that was
+  // most recently started but not ended.
+  //
+  // Note that, unlike filenames, NAME is not a pointer into the
+  // .stabstr section; this is because the name as it appears in the
+  // STABS data is followed by type information.  The value passed to
+  // StartFunction is the function name alone.
+  //
+  // In languages that use name mangling, like C++, NAME is mangled.
+  virtual bool StartFunction(const std::string &name, uint64_t address) {
+    return true;
+  }
+
+  // Finish processing the function.  If ADDRESS is non-zero, it is
+  // the ending address for the function.  If ADDRESS is zero, then
+  // the function's ending address is not available, and the consumer
+  // must infer it by other means.
+  virtual bool EndFunction(uint64_t address) { return true; }
+  
+  // Report that the code at ADDRESS is attributable to line NUMBER of
+  // the source file named FILENAME.  The caller must infer the ending
+  // address of the line.
+  virtual bool Line(uint64_t address, const char *filename, int number) {
+    return true;
+  }
+
+  // Report that an exported function NAME is present at ADDRESS.
+  // The size of the function is unknown.
+  virtual bool Extern(const std::string &name, uint64_t address) {
+    return true;
+  }
+
+  // Report a warning.  FORMAT is a printf-like format string,
+  // specifying how to format the subsequent arguments.
+  virtual void Warning(const char *format, ...) = 0;
+};
+
+} // namespace google_breakpad
+
+#endif  // COMMON_STABS_READER_H__