Microdumps: refactor out common parts of minidump_writer.cc

This change is a pure refactoring of the common bits of minidump_writer.cc
that will be shared soon with the upcoming microdump_writer.cc.
In particular, this CL is extracting the following classes:
- ThreadInfo: handles the state of the threads in the crashing process.
- RawContextCPU: typedef for arch-specific CPU context structure.
- UContextReader: Fills out a dump RawContextCPU structure from the
  ucontext struct provided by the kernel (arch-dependent).
- SeccompUnwinder: cleans out the stack frames of the Seccomp sandbox
  on the supported architectures.
- MappingInfo: handles information about mappings

BUG=chromium:410294
R=mmandlis@chromium.org

Review URL: https://breakpad.appspot.com/4684002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1388 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/client/linux/dump_writer_common/ucontext_reader.h

@@ -0,0 +1,64 @@
+// Copyright (c) 2014, 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.
+
+#ifndef CLIENT_LINUX_DUMP_WRITER_COMMON_UCONTEXT_READER_H
+#define CLIENT_LINUX_DUMP_WRITER_COMMON_UCONTEXT_READER_H
+
+#include <sys/ucontext.h>
+#include <sys/user.h>
+
+#include "client/linux/dump_writer_common/raw_context_cpu.h"
+#include "common/memory.h"
+#include "google_breakpad/common/minidump_format.h"
+
+namespace google_breakpad {
+
+// Wraps platform-dependent implementations of accessors to ucontext structs.
+struct UContextReader {
+  static uintptr_t GetStackPointer(const struct ucontext* uc);
+
+  static uintptr_t GetInstructionPointer(const struct ucontext* uc);
+
+  // Juggle a arch-specific ucontext into a minidump format
+  //   out: the minidump structure
+  //   info: the collection of register structures.
+#if defined(__i386__) || defined(__x86_64)
+  static void FillCPUContext(RawContextCPU *out, const ucontext *uc,
+                             const struct _libc_fpstate* fp);
+#elif defined(__aarch64__)
+  static void FillCPUContext(RawContextCPU *out, const ucontext *uc,
+                             const struct fpsimd_context* fpregs);
+#else
+  static void FillCPUContext(RawContextCPU *out, const ucontext *uc);
+#endif
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_DUMP_WRITER_COMMON_UCONTEXT_READER_H