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// -*- mode: c++ -*-
// Copyright 2009 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.
// This file contains definitions related to the STABS reader and
// its handler interfaces.
// 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 reader assumes that the system's <a.out.h> and <stab.h>
// headers accurately describe the layout of the STABS data; this code
// is not cross-platform safe.
#ifndef COMMON_LINUX_STABS_READER_H__
#define COMMON_LINUX_STABS_READER_H__
#include <stdint.h>
#include <cstddef>
#include <a.out.h>
#include <string>
namespace google_breakpad {
class StabsHandler;
class StabsReader {
public:
// Create a reader for the STABS debug information whose .stab
// section is the STAB_SIZE bytes at STAB, and whose .stabstr
// section is the STABSTR_SIZE bytes at STABSTR. The reader will
// call the member functions of HANDLER to report the information it
// finds, when the reader's 'Process' member function is called.
//
// 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,
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.
bool Process();
private:
// Return the name of the current symbol.
const char *SymbolString();
// Return the value of the current symbol.
const uint64_t SymbolValue() {
return symbol_->n_value;
}
// 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();
// The debugging information we're reading.
const struct nlist *symbols_, *symbols_end_;
const uint8_t *stabstr_;
size_t stabstr_size_;
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 symbol we're processing.
const struct nlist *symbol_;
// The current source file name.
const char *current_source_file_;
};
// 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 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_LINUX_STABS_READER_H__
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