The Tor Browser: tools/profiler/platform-macos.cc@97036ab72558 (annotated)

tools/profiler/platform-macos.cc@97036ab72558 (annotated)

tools/profiler/platform-macos.cc

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* 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 <dlfcn.h>
 #include <unistd.h>
 #include <sys/mman.h>
 #include <mach/mach_init.h>
 #include <mach-o/dyld.h>
 #include <mach-o/getsect.h>
 #include <AvailabilityMacros.h>
 #include <pthread.h>
 #include <semaphore.h>
 #include <signal.h>
 #include <libkern/OSAtomic.h>
 #include <mach/mach.h>
 #include <mach/semaphore.h>
 #include <mach/task.h>
 #include <mach/vm_statistics.h>
 #include <sys/time.h>
 #include <sys/resource.h>
 #include <sys/types.h>
 #include <sys/sysctl.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <math.h>
 #include "nsThreadUtils.h"
 #include "platform.h"
 #include "TableTicker.h"
 #include "UnwinderThread2.h"  /* uwt__register_thread_for_profiling */
 // this port is based off of v8 svn revision 9837
 // XXX: this is a very stubbed out implementation
 // that only supports a single Sampler
 struct SamplerRegistry {
   static void AddActiveSampler(Sampler *sampler) {
     ASSERT(!SamplerRegistry::sampler);
     SamplerRegistry::sampler = sampler;
   }
   static void RemoveActiveSampler(Sampler *sampler) {
     SamplerRegistry::sampler = NULL;
   }
   static Sampler *sampler;
 };
 Sampler *SamplerRegistry::sampler = NULL;
 // 0 is never a valid thread id on MacOSX since a ptread_t is
 // a pointer.
 static const pthread_t kNoThread = (pthread_t) 0;
 void OS::Startup() {
 }
 void OS::Sleep(int milliseconds) {
   usleep(1000 * milliseconds);
 }
 void OS::SleepMicro(int microseconds) {
   usleep(microseconds);
 }
 Thread::Thread(const char* name)
     : stack_size_(0) {
   set_name(name);
 }
 Thread::~Thread() {
 }
 static void SetThreadName(const char* name) {
   // pthread_setname_np is only available in 10.6 or later, so test
   // for it at runtime.
   int (*dynamic_pthread_setname_np)(const char*);
   *reinterpret_cast<void**>(&dynamic_pthread_setname_np) =
     dlsym(RTLD_DEFAULT, "pthread_setname_np");
   if (!dynamic_pthread_setname_np)
     return;
   // Mac OS X does not expose the length limit of the name, so hardcode it.
   static const int kMaxNameLength = 63;
   USE(kMaxNameLength);
   ASSERT(Thread::kMaxThreadNameLength <= kMaxNameLength);
   dynamic_pthread_setname_np(name);
 }
 static void* ThreadEntry(void* arg) {
   Thread* thread = reinterpret_cast<Thread*>(arg);
   thread->thread_ = pthread_self();
   SetThreadName(thread->name());
   ASSERT(thread->thread_ != kNoThread);
   thread->Run();
   return NULL;
 }
 void Thread::set_name(const char* name) {
   strncpy(name_, name, sizeof(name_));
   name_[sizeof(name_) - 1] = '\0';
 }
 void Thread::Start() {
   pthread_attr_t* attr_ptr = NULL;
   pthread_attr_t attr;
   if (stack_size_ > 0) {
     pthread_attr_init(&attr);
     pthread_attr_setstacksize(&attr, static_cast<size_t>(stack_size_));
     attr_ptr = &attr;
   }
   pthread_create(&thread_, attr_ptr, ThreadEntry, this);
   ASSERT(thread_ != kNoThread);
 }
 void Thread::Join() {
   pthread_join(thread_, NULL);
 }
 class PlatformData : public Malloced {
  public:
   PlatformData() : profiled_thread_(mach_thread_self())
   {
     profiled_pthread_ = pthread_from_mach_thread_np(profiled_thread_);
   }
   ~PlatformData() {
     // Deallocate Mach port for thread.
     mach_port_deallocate(mach_task_self(), profiled_thread_);
   }
   thread_act_t profiled_thread() { return profiled_thread_; }
   pthread_t profiled_pthread() { return profiled_pthread_; }
  private:
   // Note: for profiled_thread_ 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 profiled_thread_;
   // we also store the pthread because Mach threads have no concept of stack
   // and we want to be able to get the stack size when we need to unwind the
   // stack using frame pointers.
   pthread_t profiled_pthread_;
 };
 /* static */ PlatformData*
 Sampler::AllocPlatformData(int aThreadId)
 {
   return new PlatformData;
 }
 /* static */ void
 Sampler::FreePlatformData(PlatformData* aData)
 {
   delete aData;
 }
 class SamplerThread : public Thread {
  public:
   explicit SamplerThread(double interval)
       : Thread("SamplerThread")
       , intervalMicro_(floor(interval * 1000 + 0.5))
   {
     if (intervalMicro_ <= 0) {
       intervalMicro_ = 1;
     }
   }
   static void AddActiveSampler(Sampler* sampler) {
     mozilla::MutexAutoLock lock(*Sampler::sRegisteredThreadsMutex);
     SamplerRegistry::AddActiveSampler(sampler);
     if (instance_ == NULL) {
       instance_ = new SamplerThread(sampler->interval());
       instance_->Start();
     }
   }
   static void RemoveActiveSampler(Sampler* sampler) {
     mozilla::MutexAutoLock lock(*Sampler::sRegisteredThreadsMutex);
     instance_->Join();
     //XXX: unlike v8 we need to remove the active sampler after doing the Join
     // because we drop the sampler immediately
     SamplerRegistry::RemoveActiveSampler(sampler);
     delete instance_;
     instance_ = NULL;
   }
   // Implement Thread::Run().
   virtual void Run() {
     while (SamplerRegistry::sampler->IsActive()) {
       if (!SamplerRegistry::sampler->IsPaused()) {
         mozilla::MutexAutoLock lock(*Sampler::sRegisteredThreadsMutex);
         std::vector<ThreadInfo*> threads =
           SamplerRegistry::sampler->GetRegisteredThreads();
         for (uint32_t i = 0; i < threads.size(); i++) {
           ThreadInfo* info = threads[i];
           // This will be null if we're not interested in profiling this thread.
           if (!info->Profile())
             continue;
           PseudoStack::SleepState sleeping = info->Stack()->observeSleeping();
           if (sleeping == PseudoStack::SLEEPING_AGAIN) {
             info->Profile()->DuplicateLastSample();
             //XXX: This causes flushes regardless of jank-only mode
             info->Profile()->flush();
             continue;
           }
           ThreadProfile* thread_profile = info->Profile();
           SampleContext(SamplerRegistry::sampler, thread_profile);
         }
       }
       OS::SleepMicro(intervalMicro_);
     }
   }
   void SampleContext(Sampler* sampler, ThreadProfile* thread_profile) {
     thread_act_t profiled_thread =
       thread_profile->GetPlatformData()->profiled_thread();
     TickSample sample_obj;
     TickSample* sample = &sample_obj;
     if (KERN_SUCCESS != thread_suspend(profiled_thread)) return;
 #if V8_HOST_ARCH_X64
     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 V8_HOST_ARCH_IA32
     thread_state_flavor_t flavor = i386_THREAD_STATE;
     i386_thread_state_t state;
     mach_msg_type_number_t count = i386_THREAD_STATE_COUNT;
 #if __DARWIN_UNIX03
 #define REGISTER_FIELD(name) __e ## name
 #else
 #define REGISTER_FIELD(name) e ## name
 #endif  // __DARWIN_UNIX03
 #else
 #error Unsupported Mac OS X host architecture.
 #endif  // V8_HOST_ARCH
     if (thread_get_state(profiled_thread,
                          flavor,
                          reinterpret_cast<natural_t*>(&state),
                          &count) == KERN_SUCCESS) {
       sample->pc = reinterpret_cast<Address>(state.REGISTER_FIELD(ip));
       sample->sp = reinterpret_cast<Address>(state.REGISTER_FIELD(sp));
       sample->fp = reinterpret_cast<Address>(state.REGISTER_FIELD(bp));
       sample->timestamp = mozilla::TimeStamp::Now();
       sample->threadProfile = thread_profile;
       sampler->Tick(sample);
     }
     thread_resume(profiled_thread);
   }
   int intervalMicro_;
   //RuntimeProfilerRateLimiter rate_limiter_;
   static SamplerThread* instance_;
   DISALLOW_COPY_AND_ASSIGN(SamplerThread);
 };
 #undef REGISTER_FIELD
 SamplerThread* SamplerThread::instance_ = NULL;
 Sampler::Sampler(double interval, bool profiling, int entrySize)
     : // isolate_(isolate),
       interval_(interval),
       profiling_(profiling),
       paused_(false),
       active_(false),
       entrySize_(entrySize) /*,
       samples_taken_(0)*/ {
 }
 Sampler::~Sampler() {
   ASSERT(!IsActive());
 }
 void Sampler::Start() {
   ASSERT(!IsActive());
   SetActive(true);
   SamplerThread::AddActiveSampler(this);
 }
 void Sampler::Stop() {
   ASSERT(IsActive());
   SetActive(false);
   SamplerThread::RemoveActiveSampler(this);
 }
 pthread_t
 Sampler::GetProfiledThread(PlatformData* aData)
 {
   return aData->profiled_pthread();
 }
 #include <sys/syscall.h>
 pid_t gettid()
 {
   return (pid_t) syscall(SYS_thread_selfid);
 }
 /* static */ Thread::tid_t
 Thread::GetCurrentId()
 {
   return gettid();
 }
 bool Sampler::RegisterCurrentThread(const char* aName,
                                     PseudoStack* aPseudoStack,
                                     bool aIsMainThread, void* stackTop)
 {
   if (!Sampler::sRegisteredThreadsMutex)
     return false;
   mozilla::MutexAutoLock lock(*Sampler::sRegisteredThreadsMutex);
   int id = gettid();
   for (uint32_t i = 0; i < sRegisteredThreads->size(); i++) {
     ThreadInfo* info = sRegisteredThreads->at(i);
     if (info->ThreadId() == id) {
       // Thread already registered. This means the first unregister will be
       // too early.
       ASSERT(false);
       return false;
     }
   }
   set_tls_stack_top(stackTop);
   ThreadInfo* info = new ThreadInfo(aName, id,
     aIsMainThread, aPseudoStack, stackTop);
   if (sActiveSampler) {
     sActiveSampler->RegisterThread(info);
   }
   sRegisteredThreads->push_back(info);
   uwt__register_thread_for_profiling(stackTop);
   return true;
 }
 void Sampler::UnregisterCurrentThread()
 {
   if (!Sampler::sRegisteredThreadsMutex)
     return;
   tlsStackTop.set(nullptr);
   mozilla::MutexAutoLock lock(*Sampler::sRegisteredThreadsMutex);
   int id = gettid();
   for (uint32_t i = 0; i < sRegisteredThreads->size(); i++) {
     ThreadInfo* info = sRegisteredThreads->at(i);
     if (info->ThreadId() == id) {
       delete info;
       sRegisteredThreads->erase(sRegisteredThreads->begin() + i);
       break;
     }
   }
 }
 void TickSample::PopulateContext(void* aContext)
 {
   // Note that this asm changes if PopulateContext's parameter list is altered
 #if defined(SPS_PLAT_amd64_darwin)
   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"(sp),
       "=r"(fp)
   );
 #elif defined(SPS_PLAT_x86_darwin)
   asm (
       // Compute caller's %esp by adding to %ebp:
       // 4 bytes for aContext + 4 bytes for return address +
       // 4 bytes for previous %ebp
       "leal 0xc(%%ebp), %0\n\t"
       // Dereference %ebp to get previous %ebp
       "movl (%%ebp), %1\n\t"
       :
       "=r"(sp),
       "=r"(fp)
   );
 #else
 # error "Unsupported architecture"
 #endif
   pc = reinterpret_cast<Address>(__builtin_extract_return_addr(
                                     __builtin_return_address(0)));
 }

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tools/profiler/platform-macos.cc@97036ab72558 (annotated)

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