Initial implementation of x86 stackwalker (#9). r=bryner

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@12 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/processor/stackwalker_x86.h

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+// Copyright (C) 2006 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// stackwalker_x86.h: x86-specific stackwalker.
+//
+// Provides stack frames given x86 register context and a memory region
+// corresponding to an x86 stack.
+//
+// Author: Mark Mentovai
+
+
+#ifndef PROCESSOR_STACKWALKER_X86_H__
+#define PROCESSOR_STACKWALKER_X86_H__
+
+
+#include "google/airbag_types.h"
+#include "processor/stackwalker.h"
+#include "processor/minidump_format.h"
+
+
+namespace google_airbag {
+
+
+class MinidumpContext;
+class MinidumpModuleList;
+
+
+class StackwalkerX86 : public Stackwalker {
+  public:
+    // context is a MinidumpContext object that gives access to x86-specific
+    // register state corresponding to the innermost called frame to be
+    // included in the stack.  memory and modules are passed directly through
+    // to the base Stackwalker constructor.
+    StackwalkerX86(MinidumpContext*    context,
+                   MemoryRegion*       memory,
+                   MinidumpModuleList* modules);
+
+  private:
+    // Implementation of Stackwalker, using x86 context (%ebp, %eip) and
+    // stack conventions (saved %ebp at [%ebp], saved %eip at 4[%ebp]).
+    bool GetContextFrame(StackFrame* frame);
+    bool GetCallerFrame(StackFrame* frame);
+
+    // Stores the CPU context corresponding to the innermost stack frame to
+    // be returned by GetContextFrame.
+    const MDRawContextX86* context_;
+
+    // Stores the frame pointer returned in the last stack frame returned by
+    // GetContextFrame or GetCallerFrame.
+    u_int32_t              last_frame_pointer_;
+};
+
+
+} // namespace google_airbag
+
+
+#endif // PROCESSOR_STACKWALKER_X86_H__