Breakpad Linux Dumper: Add DWARF support.

This adds DWARF support to the Breakpad Linux dumper. This is
implemented as two handler classes: google_breakpad::DwarfCUToModule
accepts data from dwarf2reader::CompilationUnit, and
google_breakpad::DwarfLineToModule accepts data from a
dwarf2reader::LineInfo, each populating a google_breakpad::Module with
the results. Behaviors specific to particular source languages are
handled by instances of a new class, google_breakpad::Language.

An input executable may contain both STABS and DWARF debugging
information: the dumper automatically recognizes what sorts of
information are available, and integrates the data into a single
output file.

All classes have unit tests, providing line and branch coverage of all
interesting code. Unit tests are written using the Google C++ Testing
Framework, and the Google C++ Mocking Framework where appropriate.

a=jimblandy, r=ccoutant


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@497 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/common/linux/language.h

@@ -0,0 +1,81 @@
+// -*- mode: c++ -*-
+
+// Copyright (c) 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.
+
+// language.h: defines google_breakpad::Language, providing
+// language-specific operations for use by the dumper.
+
+#ifndef COMMON_LINUX_LANGUAGE_H__
+#define COMMON_LINUX_LANGUAGE_H__
+
+#include <string>
+
+namespace google_breakpad {
+
+using std::string;
+
+// An abstract base class for language-specific operations. We choose
+// an instance of a subclass of this when we find the CU's language.
+// This class's definitions are appropriate for CUs with no specified
+// language.
+class Language {
+ public:
+  // Return true if this language has functions to which we can assign
+  // line numbers. (Debugging info for assembly language, for example,
+  // can have source location information, but does not have functions
+  // recorded using DW_TAG_subprogram DIEs.)
+  virtual bool HasFunctions() const { return true; }
+
+  // Construct a fully-qualified, language-appropriate form of NAME,
+  // given that PARENT_NAME is the name of the construct enclosing
+  // NAME. If PARENT_NAME is the empty string, then NAME is a
+  // top-level name.
+  //
+  // This API sort of assumes that a fully-qualified name is always
+  // some simple textual composition of the unqualified name and its
+  // parent's name, and that we don't need to know anything else about
+  // the parent or the child (say, their DIEs' tags) to do the job.
+  // This is true for the languages we support at the moment, and
+  // keeps things concrete. Perhaps a more refined operation would
+  // take into account the parent and child DIE types, allow languages
+  // to use their own data type for complex parent names, etc. But if
+  // C++ doesn't need all that, who would?
+  virtual string MakeQualifiedName (const string &parent_name,
+                                    const string &name) const = 0;
+
+  // Instances for specific languages.
+  static const Language * const CPlusPlus,
+                        * const Java,
+                        * const Assembler;
+};
+
+} // namespace google_breakpad
+
+#endif  // COMMON_LINUX_LANGUAGE_H__