components/tracing/common/stack_sampler_android.cc

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/tracing/common/stack_sampler_android.h"

#include "base/profiler/profile_builder.h"
#include "base/trace_event/trace_event.h"

namespace tracing {
namespace {
constexpr size_t kMaxFrameDepth = 48;
}  // namespace

StackSamplerAndroid::StackSamplerAndroid(base::PlatformThreadId tid)
    : tid_(tid) {}

StackSamplerAndroid::~StackSamplerAndroid() = default;

// Unimplemented. StackSamplerAndroid needs to be implemented in terms of
// base::StackSamplerImpl to make use of this.
void StackSamplerAndroid::AddAuxUnwinder(base::Unwinder* unwinder) {}

void StackSamplerAndroid::RecordStackFrames(
    StackBuffer* stack_buffer,
    base::ProfileBuilder* profile_builder) {
  if (!unwinder_.is_initialized()) {
    // May block on disk access. This function is executed on the profiler
    // thread, so this will only block profiling execution.
    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cpu_profiler"),
                 "StackUnwinderAndroid::Initialize");
    unwinder_.Initialize();
  }
  const void* pcs[kMaxFrameDepth];
  size_t depth = unwinder_.TraceStack(tid_, stack_buffer, pcs, kMaxFrameDepth);
  std::vector<base::Frame> frames;
  frames.reserve(depth);
  for (size_t i = 0; i < depth; ++i) {
    // TODO(ssid): Add support for obtaining modules here.
    frames.emplace_back(reinterpret_cast<uintptr_t>(pcs[i]), nullptr);
  }
  profile_builder->OnSampleCompleted(std::move(frames));
}

}  // namespace tracing