breakpad/src/processor/stackwalker.cc

// Copyright (c) 2006, Google Inc.
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// modification, are permitted provided that the following conditions are
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//
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// stackwalker.cc: Generic stackwalker.
//
// See stackwalker.h for documentation.
//
// Author: Mark Mentovai


#include <memory>

#include "processor/stackwalker.h"
#include "google/symbol_supplier.h"
#include "processor/minidump.h"
#include "processor/source_line_resolver.h"
#include "processor/stackwalker_ppc.h"
#include "processor/stackwalker_x86.h"

namespace google_airbag {

using std::auto_ptr;


Stackwalker::Stackwalker(MemoryRegion *memory, MinidumpModuleList *modules,
                         SymbolSupplier *supplier)
    : memory_(memory), stack_frame_info_(), modules_(modules),
      supplier_(supplier) {
}


void Stackwalker::Walk(StackFrames *frames) {
  frames->clear();
  stack_frame_info_.clear();
  SourceLineResolver resolver;

  // Begin with the context frame, and keep getting callers until there are
  // no more.

  auto_ptr<StackFrame> frame(new StackFrame());
  auto_ptr<StackFrameInfo> frame_info(new StackFrameInfo());
  bool valid = GetContextFrame(frame.get());
  while (valid) {
    // frame already contains a good frame with properly set instruction and
    // frame_pointer fields.  The frame structure comes from either the
    // context frame (above) or a caller frame (below).

    // Resolve the module information, if a module map was provided.
    if (modules_) {
      MinidumpModule *module =
          modules_->GetModuleForAddress(frame->instruction);
      if (module) {
        frame->module_name = *(module->GetName());
        frame->module_base = module->base_address();
        if (modules_ && supplier_) {
          string symbol_file =
            supplier_->GetSymbolFile(module);
          if (!symbol_file.empty()) {
            resolver.LoadModule(*(module->GetName()), symbol_file);
            resolver.FillSourceLineInfo(frame.get(), frame_info.get());
          }
        }
      }
    }

    // Copy the frame into the frames vector.
    frames->push_back(*frame);
    stack_frame_info_.push_back(*frame_info);

    // Use a new object for the next frame, even though the old object was
    // copied.  If StackFrame provided some sort of Clear() method, then
    // the same frame could be reused.
    frame.reset(new StackFrame());
    frame_info.reset(new StackFrameInfo());

    // Get the next frame.
    valid = GetCallerFrame(frame.get(), frames);
  }
}


// static
Stackwalker* Stackwalker::StackwalkerForCPU(MinidumpContext *context,
                                            MemoryRegion *memory,
                                            MinidumpModuleList *modules,
                                            SymbolSupplier *supplier) {
  Stackwalker *cpu_stackwalker = NULL;

  u_int32_t cpu = context->GetContextCPU();
  switch (cpu) {
    case MD_CONTEXT_X86:
      cpu_stackwalker = new StackwalkerX86(context->GetContextX86(),
                                           memory, modules, supplier);
      break;

    case MD_CONTEXT_PPC:
      cpu_stackwalker = new StackwalkerPPC(context->GetContextPPC(),
                                           memory, modules, supplier);
      break;
  }

  return cpu_stackwalker;
}


} // namespace google_airbag