* Added breakpad support for Linux.

thirdparty/breakpad/common/stabs_reader.cc

@@ -0,0 +1,311 @@
+// 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>
+
+// This file implements the google_breakpad::StabsReader class.
+// See stabs_reader.h.
+
+#include "common/stabs_reader.h"
+
+#include <assert.h>
+#include <stab.h>
+#include <string.h>
+
+using std::vector;
+
+namespace google_breakpad {
+
+StabsReader::EntryIterator::EntryIterator(const ByteBuffer *buffer,
+                                          bool big_endian, size_t value_size)
+    : value_size_(value_size), cursor_(buffer, big_endian) {
+  // Actually, we could handle weird sizes just fine, but they're
+  // probably mistakes --- expressed in bits, say.
+  assert(value_size == 4 || value_size == 8);
+  entry_.index = 0;
+  Fetch();
+}
+
+void StabsReader::EntryIterator::Fetch() {
+  cursor_
+      .Read(4, false, &entry_.name_offset)
+      .Read(1, false, &entry_.type)
+      .Read(1, false, &entry_.other)
+      .Read(2, false, &entry_.descriptor)
+      .Read(value_size_, false, &entry_.value);
+  entry_.at_end = !cursor_;
+}
+
+StabsReader::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)
+    : entries_(stab, stab_size),
+      strings_(stabstr, stabstr_size),
+      iterator_(&entries_, big_endian, value_size),
+      unitized_(unitized),
+      handler_(handler),
+      string_offset_(0),
+      next_cu_string_offset_(0),
+      current_source_file_(NULL) { }
+
+const char *StabsReader::SymbolString() {
+  ptrdiff_t offset = string_offset_ + iterator_->name_offset;
+  if (offset < 0 || (size_t) offset >= strings_.Size()) {
+    handler_->Warning("symbol %d: name offset outside the string section\n",
+                      iterator_->index);
+    // Return our null string, to keep our promise about all names being
+    // taken from the string section.
+    offset = 0;
+  }
+  return reinterpret_cast<const char *>(strings_.start + offset);
+}
+
+bool StabsReader::Process() {
+  while (!iterator_->at_end) {
+    if (iterator_->type == N_SO) {
+      if (! ProcessCompilationUnit())
+        return false;
+    } else if (iterator_->type == N_UNDF && unitized_) {
+      // In unitized STABS (including Linux STABS, and pretty much anything
+      // else that puts STABS data in sections), at the head of each
+      // compilation unit's entries there is an N_UNDF stab giving the
+      // number of symbols in the compilation unit, and the number of bytes
+      // that compilation unit's strings take up in the .stabstr section.
+      // Each CU's strings are separate; the n_strx values are offsets
+      // within the current CU's portion of the .stabstr section.
+      //
+      // As an optimization, the GNU linker combines all the
+      // compilation units into one, with a single N_UNDF at the
+      // beginning. However, other linkers, like Gold, do not perform
+      // this optimization.
+      string_offset_ = next_cu_string_offset_;
+      next_cu_string_offset_ = iterator_->value;
+      ++iterator_;
+    }
+#if defined(HAVE_MACH_O_NLIST_H)
+    // Export symbols in Mach-O binaries look like this.
+    // This is necessary in order to be able to dump symbols
+    // from OS X system libraries.
+    else if ((iterator_->type & N_STAB) == 0 &&
+               (iterator_->type & N_TYPE) == N_SECT) {
+      ProcessExtern();
+    }
+#endif
+    else {
+      ++iterator_;
+    }
+  }
+  return true;
+}
+
+bool StabsReader::ProcessCompilationUnit() {
+  assert(!iterator_->at_end && iterator_->type == N_SO);
+
+  // There may be an N_SO entry whose name ends with a slash,
+  // indicating the directory in which the compilation occurred.
+  // The build directory defaults to NULL.
+  const char *build_directory = NULL;  
+  {
+    const char *name = SymbolString();
+    if (name[0] && name[strlen(name) - 1] == '/') {
+      build_directory = name;
+      ++iterator_;
+    }
+  }
+      
+  // We expect to see an N_SO entry with a filename next, indicating
+  // the start of the compilation unit.
+  {
+    if (iterator_->at_end || iterator_->type != N_SO)
+      return true;
+    const char *name = SymbolString();
+    if (name[0] == '\0') {
+      // This seems to be a stray end-of-compilation-unit marker;
+      // consume it, but don't report the end, since we didn't see a
+      // beginning.
+      ++iterator_;
+      return true;
+    }
+    current_source_file_ = name;
+  }
+
+  if (! handler_->StartCompilationUnit(current_source_file_,
+                                       iterator_->value,
+                                       build_directory))
+    return false;
+
+  ++iterator_;
+
+  // The STABS documentation says that some compilers may emit
+  // additional N_SO entries with names immediately following the
+  // first, and that they should be ignored.  However, the original
+  // Breakpad STABS reader doesn't ignore them, so we won't either.
+
+  // Process the body of the compilation unit, up to the next N_SO.
+  while (!iterator_->at_end && iterator_->type != N_SO) {
+    if (iterator_->type == N_FUN) {
+      if (! ProcessFunction())
+        return false;
+    } else if (iterator_->type == N_SLINE) {
+      // Mac OS X STABS place SLINE records before functions.
+      Line line;
+      // The value of an N_SLINE entry that appears outside a function is
+      // the absolute address of the line.
+      line.address = iterator_->value;
+      line.filename = current_source_file_;
+      // The n_desc of a N_SLINE entry is the line number.  It's a
+      // signed 16-bit field; line numbers from 32768 to 65535 are
+      // stored as n-65536.
+      line.number = (uint16_t) iterator_->descriptor;
+      queued_lines_.push_back(line);
+      ++iterator_;
+    } else if (iterator_->type == N_SOL) {
+      current_source_file_ = SymbolString();
+      ++iterator_;
+    } else {
+      // Ignore anything else.
+      ++iterator_;
+    }
+  }
+
+  // An N_SO with an empty name indicates the end of the compilation
+  // unit.  Default to zero.
+  uint64_t ending_address = 0;
+  if (!iterator_->at_end) {
+    assert(iterator_->type == N_SO);
+    const char *name = SymbolString();
+    if (name[0] == '\0') {
+      ending_address = iterator_->value;
+      ++iterator_;
+    }
+  }
+
+  if (! handler_->EndCompilationUnit(ending_address))
+    return false;
+
+  queued_lines_.clear();
+
+  return true;
+}          
+
+bool StabsReader::ProcessFunction() {
+  assert(!iterator_->at_end && iterator_->type == N_FUN);
+
+  uint64_t function_address = iterator_->value;
+  // The STABS string for an N_FUN entry is the name of the function,
+  // followed by a colon, followed by type information for the
+  // function.  We want to pass the name alone to StartFunction.
+  const char *stab_string = SymbolString();
+  const char *name_end = strchr(stab_string, ':');
+  if (! name_end)
+    name_end = stab_string + strlen(stab_string);
+  std::string name(stab_string, name_end - stab_string);
+  if (! handler_->StartFunction(name, function_address))
+    return false;
+  ++iterator_;
+
+  // If there were any SLINE records given before the function, report them now.
+  for (vector<Line>::const_iterator it = queued_lines_.begin();
+       it != queued_lines_.end(); it++) {
+    if (!handler_->Line(it->address, it->filename, it->number))
+      return false;
+  }
+  queued_lines_.clear();
+  
+  while (!iterator_->at_end) {
+    if (iterator_->type == N_SO || iterator_->type == N_FUN)
+      break;
+    else if (iterator_->type == N_SLINE) {
+      // The value of an N_SLINE entry is the offset of the line from
+      // the function's start address.
+      uint64_t line_address = function_address + iterator_->value;
+      // The n_desc of a N_SLINE entry is the line number.  It's a
+      // signed 16-bit field; line numbers from 32768 to 65535 are
+      // stored as n-65536.
+      uint16_t line_number = iterator_->descriptor;
+      if (! handler_->Line(line_address, current_source_file_, line_number))
+        return false;
+      ++iterator_;
+    } else if (iterator_->type == N_SOL) {
+      current_source_file_ = SymbolString();
+      ++iterator_;
+    } else
+      // Ignore anything else.
+      ++iterator_;
+  }
+
+  // We've reached the end of the function. See if we can figure out its
+  // ending address.
+  uint64_t ending_address = 0;
+  if (!iterator_->at_end) {
+    assert(iterator_->type == N_SO || iterator_->type == N_FUN);
+    if (iterator_->type == N_FUN) {
+      const char *name = SymbolString();
+      if (name[0] == '\0') {
+        // An N_FUN entry with no name is a terminator for this function;
+        // its value is the function's size.
+        ending_address = function_address + iterator_->value;
+        ++iterator_;
+      } else {
+        // An N_FUN entry with a name is the next function, and we can take
+        // its value as our ending address. Don't advance the iterator, as
+        // we'll use this symbol to start the next function as well.
+        ending_address = iterator_->value;
+      }
+    } else {
+      // An N_SO entry could be an end-of-compilation-unit marker, or the
+      // start of the next compilation unit, but in either case, its value
+      // is our ending address. We don't advance the iterator;
+      // ProcessCompilationUnit will decide what to do with this symbol.
+      ending_address = iterator_->value;
+    }
+  }
+
+  if (! handler_->EndFunction(ending_address))
+    return false;
+
+  return true;
+}
+
+bool StabsReader::ProcessExtern() {
+#if defined(HAVE_MACH_O_NLIST_H)
+  assert(!iterator_->at_end &&
+         (iterator_->type & N_STAB) == 0 &&
+         (iterator_->type & N_TYPE) == N_SECT);
+#endif
+
+  // TODO(mark): only do symbols in the text section?
+  if (!handler_->Extern(SymbolString(), iterator_->value))
+    return false;
+
+  ++iterator_;
+  return true;
+}
+
+} // namespace google_breakpad