/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <unistd.h>
#include <sys/mman.h>
#include <mach/mach_init.h>
#include <mach-o/getsect.h>

#include <AvailabilityMacros.h>

#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <libkern/OSAtomic.h>
#include <libproc.h>
#include <mach/mach.h>
#include <mach/semaphore.h>
#include <mach/task.h>
#include <mach/thread_act.h>
#include <mach/vm_statistics.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <math.h>

// this port is based off of v8 svn revision 9837

int profiler_current_process_id() { return getpid(); }

int profiler_current_thread_id() {
  return static_cast<int>(static_cast<pid_t>(syscall(SYS_thread_selfid)));
}

void* GetStackTop(void* aGuess) {
  pthread_t thread = pthread_self();
  return pthread_get_stackaddr_np(thread);
}

class PlatformData {
 public:
  explicit PlatformData(int aThreadId) : mProfiledThread(mach_thread_self()) {
    MOZ_COUNT_CTOR(PlatformData);
  }

  ~PlatformData() {
    // Deallocate Mach port for thread.
    mach_port_deallocate(mach_task_self(), mProfiledThread);

    MOZ_COUNT_DTOR(PlatformData);
  }

  thread_act_t ProfiledThread() const { return mProfiledThread; }

  RunningTimes& PreviousThreadRunningTimesRef() {
    return mPreviousThreadRunningTimes;
  }

 private:
  // Note: for mProfiledThread Mach primitives are used instead of pthread's
  // because the latter doesn't provide thread manipulation primitives required.
  // For details, consult "Mac OS X Internals" book, Section 7.3.
  thread_act_t mProfiledThread;
  RunningTimes mPreviousThreadRunningTimes;
};

////////////////////////////////////////////////////////////////////////
// BEGIN Sampler target specifics

Sampler::Sampler(PSLockRef aLock) {}

void Sampler::Disable(PSLockRef aLock) {}

static void StreamMetaPlatformSampleUnits(PSLockRef aLock,
                                          SpliceableJSONWriter& aWriter) {
  // Microseconds.
  aWriter.StringProperty("threadCPUDelta", "\u00B5s");
}

static RunningTimes GetThreadRunningTimesDiff(
    PSLockRef aLock, const RegisteredThread& aRegisteredThread) {
  AUTO_PROFILER_STATS(GetRunningTimes);

  PlatformData* platformData = aRegisteredThread.GetPlatformData();
  MOZ_RELEASE_ASSERT(platformData);

  const RunningTimes newRunningTimes = GetRunningTimesWithTightTimestamp(
      [platformData](RunningTimes& aRunningTimes) {
        AUTO_PROFILER_STATS(GetRunningTimes_thread_info);
        thread_basic_info_data_t threadBasicInfo;
        mach_msg_type_number_t basicCount = THREAD_BASIC_INFO_COUNT;
        if (thread_info(platformData->ProfiledThread(), THREAD_BASIC_INFO,
                        reinterpret_cast<thread_info_t>(&threadBasicInfo),
                        &basicCount) == KERN_SUCCESS &&
            basicCount == THREAD_BASIC_INFO_COUNT) {
          uint64_t userTimeUs =
              uint64_t(threadBasicInfo.user_time.seconds) *
                  uint64_t(USEC_PER_SEC) +
              uint64_t(threadBasicInfo.user_time.microseconds);
          uint64_t systemTimeUs =
              uint64_t(threadBasicInfo.system_time.seconds) *
                  uint64_t(USEC_PER_SEC) +
              uint64_t(threadBasicInfo.system_time.microseconds);
          aRunningTimes.ResetThreadCPUDelta(userTimeUs + systemTimeUs);
        } else {
          aRunningTimes.ClearThreadCPUDelta();
        }
      });

  const RunningTimes diff =
      newRunningTimes - platformData->PreviousThreadRunningTimesRef();
  platformData->PreviousThreadRunningTimesRef() = newRunningTimes;
  return diff;
}

template <typename Func>
void Sampler::SuspendAndSampleAndResumeThread(
    PSLockRef aLock, const RegisteredThread& aRegisteredThread,
    const TimeStamp& aNow, const Func& aProcessRegs) {
  thread_act_t samplee_thread =
      aRegisteredThread.GetPlatformData()->ProfiledThread();

  //----------------------------------------------------------------//
  // Suspend the samplee thread and get its context.

  // We're using thread_suspend on OS X because pthread_kill (which is what we
  // at one time used on Linux) has less consistent performance and causes
  // strange crashes, see bug 1166778 and bug 1166808.  thread_suspend
  // is also just a lot simpler to use.

  if (KERN_SUCCESS != thread_suspend(samplee_thread)) {
    return;
  }

  //----------------------------------------------------------------//
  // Sample the target thread.

  // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  //
  // The profiler's "critical section" begins here.  We must be very careful
  // what we do here, or risk deadlock.  See the corresponding comment in
  // platform-linux-android.cpp for details.

#if defined(__x86_64__)
  thread_state_flavor_t flavor = x86_THREAD_STATE64;
  x86_thread_state64_t state;
  mach_msg_type_number_t count = x86_THREAD_STATE64_COUNT;
#  if __DARWIN_UNIX03
#    define REGISTER_FIELD(name) __r##name
#  else
#    define REGISTER_FIELD(name) r##name
#  endif  // __DARWIN_UNIX03
#elif defined(__aarch64__)
  thread_state_flavor_t flavor = ARM_THREAD_STATE64;
  arm_thread_state64_t state;
  mach_msg_type_number_t count = ARM_THREAD_STATE64_COUNT;
#  if __DARWIN_UNIX03
#    define REGISTER_FIELD(name) __##name
#  else
#    define REGISTER_FIELD(name) name
#  endif  // __DARWIN_UNIX03
#else
#  error "unknown architecture"
#endif

  if (thread_get_state(samplee_thread, flavor,
                       reinterpret_cast<natural_t*>(&state),
                       &count) == KERN_SUCCESS) {
    Registers regs;
#if defined(__x86_64__)
    regs.mPC = reinterpret_cast<Address>(state.REGISTER_FIELD(ip));
    regs.mSP = reinterpret_cast<Address>(state.REGISTER_FIELD(sp));
    regs.mFP = reinterpret_cast<Address>(state.REGISTER_FIELD(bp));
#elif defined(__aarch64__)
    regs.mPC = reinterpret_cast<Address>(state.REGISTER_FIELD(pc));
    regs.mSP = reinterpret_cast<Address>(state.REGISTER_FIELD(sp));
    regs.mFP = reinterpret_cast<Address>(state.REGISTER_FIELD(fp));
#else
#  error "unknown architecture"
#endif
    regs.mLR = 0;

    aProcessRegs(regs, aNow);
  }

#undef REGISTER_FIELD

  //----------------------------------------------------------------//
  // Resume the target thread.

  thread_resume(samplee_thread);

  // The profiler's critical section ends here.
  //
  // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
}

// END Sampler target specifics
////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////
// BEGIN SamplerThread target specifics

static void* ThreadEntry(void* aArg) {
  auto thread = static_cast<SamplerThread*>(aArg);
  thread->Run();
  return nullptr;
}

SamplerThread::SamplerThread(PSLockRef aLock, uint32_t aActivityGeneration,
                             double aIntervalMilliseconds)
    : mSampler(aLock),
      mActivityGeneration(aActivityGeneration),
      mIntervalMicroseconds(
          std::max(1, int(floor(aIntervalMilliseconds * 1000 + 0.5)))),
      mThread{nullptr} {
  pthread_attr_t* attr_ptr = nullptr;
  if (pthread_create(&mThread, attr_ptr, ThreadEntry, this) != 0) {
    MOZ_CRASH("pthread_create failed");
  }
}

SamplerThread::~SamplerThread() {
  pthread_join(mThread, nullptr);
  // Just in the unlikely case some callbacks were added between the end of the
  // thread and now.
  InvokePostSamplingCallbacks(std::move(mPostSamplingCallbackList),
                              SamplingState::JustStopped);
}

void SamplerThread::SleepMicro(uint32_t aMicroseconds) {
  usleep(aMicroseconds);
  // FIXME: the OSX 10.12 page for usleep says "The usleep() function is
  // obsolescent.  Use nanosleep(2) instead."  This implementation could be
  // merged with the linux-android version.  Also, this doesn't handle the
  // case where the usleep call is interrupted by a signal.
}

void SamplerThread::Stop(PSLockRef aLock) { mSampler.Disable(aLock); }

// END SamplerThread target specifics
////////////////////////////////////////////////////////////////////////

static void PlatformInit(PSLockRef aLock) {}

#if defined(HAVE_NATIVE_UNWIND)
void Registers::SyncPopulate() {
#  if defined(__x86_64__)
  asm(
      // Compute caller's %rsp by adding to %rbp:
      // 8 bytes for previous %rbp, 8 bytes for return address
      "leaq 0x10(%%rbp), %0\n\t"
      // Dereference %rbp to get previous %rbp
      "movq (%%rbp), %1\n\t"
      : "=r"(mSP), "=r"(mFP));
#  elif defined(__aarch64__)
  asm(
      // Compute caller's sp by adding to fp:
      // 8 bytes for previous fp, 8 bytes for return address
      "add %0, x29, #0x10\n\t"
      // Dereference fp to get previous fp
      "ldr %1, [x29]\n\t"
      : "=r"(mSP), "=r"(mFP));
#  else
#    error "unknown architecture"
#  endif
  mPC = reinterpret_cast<Address>(
      __builtin_extract_return_addr(__builtin_return_address(0)));
  mLR = 0;
}
#endif