Breakpad symbol dumper: Move Linux dumping classes into src/common.

The Linux symbol dumper's classes are reasonably portable, and should be
usable for the Mac dumper as well. Move them to src/common, along with
their unit tests. Update #include directives and Makefile.

a=jimblandy, r=nealsid


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@567 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 220 insertions, 0 deletions

diff --git a/src/common/stabs_reader.cc b/src/common/stabs_reader.cc
new file mode 100644
index 00000000..7c2b1cc4
--- /dev/null
+++ b/src/common/stabs_reader.cc
@@ -0,0 +1,220 @@
+// 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 <a.out.h>
+#include <stab.h>
+#include <cstring>
+#include <cassert>
+
+#include "common/stabs_reader.h"
+
+namespace google_breakpad {
+
+StabsReader::StabsReader(const uint8_t *stab,    size_t stab_size,
+                         const uint8_t *stabstr, size_t stabstr_size,
+                         StabsHandler *handler) :
+    stabstr_(stabstr),
+    stabstr_size_(stabstr_size),
+    handler_(handler),
+    string_offset_(0),
+    next_cu_string_offset_(0),
+    symbol_(NULL),
+    current_source_file_(NULL) { 
+  symbols_ = reinterpret_cast<const struct nlist *>(stab);
+  symbols_end_ = symbols_ + (stab_size / sizeof (*symbols_));
+}
+
+const char *StabsReader::SymbolString() {
+  ptrdiff_t offset = string_offset_ + symbol_->n_un.n_strx;
+  if (offset < 0 || (size_t) offset >= stabstr_size_) {
+    handler_->Warning("symbol %d: name offset outside the string section\n",
+                      symbol_ - symbols_);
+    // Return our null string, to keep our promise about all names being
+    // taken from the string section.
+    offset = 0;
+  }
+  return reinterpret_cast<const char *>(stabstr_ + offset);
+}
+
+bool StabsReader::Process() {
+  symbol_ = symbols_;
+  while (symbol_ < symbols_end_) {
+    if (symbol_->n_type == N_SO) {
+      if (! ProcessCompilationUnit())
+        return false;
+    } else if (symbol_->n_type == N_UNDF) {
+      // 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_ = SymbolValue();
+      symbol_++;
+    } else
+      symbol_++;
+  }
+  return true;
+}
+
+bool StabsReader::ProcessCompilationUnit() {
+  assert(symbol_ < symbols_end_ && symbol_->n_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;
+      symbol_++;
+    }
+  }
+      
+  // We expect to see an N_SO entry with a filename next, indicating
+  // the start of the compilation unit.
+  {
+    if (symbol_ >= symbols_end_ || symbol_->n_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.
+      symbol_++;
+      return true;
+    }
+    current_source_file_ = name;
+  }
+
+  if (! handler_->StartCompilationUnit(current_source_file_,
+                                       SymbolValue(),
+                                       build_directory))
+    return false;
+
+  symbol_++;
+
+  // 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 (symbol_ < symbols_end_ && symbol_->n_type != N_SO) {
+    if (symbol_->n_type == N_FUN) {
+      if (! ProcessFunction())
+        return false;
+    } else
+      // Ignore anything else.
+      symbol_++;
+  }
+
+  // An N_SO with an empty name indicates the end of the compilation
+  // unit.  Default to zero.
+  uint64_t ending_address = 0;
+  if (symbol_ < symbols_end_) {
+    assert(symbol_->n_type == N_SO);
+    const char *name = SymbolString();
+    if (name[0] == '\0') {
+      ending_address = SymbolValue();
+      symbol_++;
+    }
+  }
+
+  if (! handler_->EndCompilationUnit(ending_address))
+    return false;
+
+  return true;
+}          
+
+bool StabsReader::ProcessFunction() {
+  assert(symbol_ < symbols_end_ && symbol_->n_type == N_FUN);
+
+  uint64_t function_address = SymbolValue();
+  // 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;
+  symbol_++;
+
+  while (symbol_ < symbols_end_) {
+    if (symbol_->n_type == N_SO || symbol_->n_type == N_FUN)
+      break;
+    else if (symbol_->n_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 + SymbolValue();
+      // 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 = symbol_->n_desc;
+      if (! handler_->Line(line_address, current_source_file_, line_number))
+        return false;
+      symbol_++;
+    } else if (symbol_->n_type == N_SOL) {
+      current_source_file_ = SymbolString();
+      symbol_++;
+    } else
+      // Ignore anything else.
+      symbol_++;
+  }
+
+  // If there is a subsequent N_SO or N_FUN entry, its address is our
+  // end address.
+  uint64_t ending_address = 0;
+  if (symbol_ < symbols_end_) {
+    assert(symbol_->n_type == N_SO || symbol_->n_type == N_FUN);
+    ending_address = SymbolValue();
+    // Note: we do not increment symbol_ here, since we haven't consumed it.
+  }
+
+  if (! handler_->EndFunction(ending_address))
+    return false;
+
+  return true;
+}
+
+} // namespace google_breakpad