Move *BSD and Solaris Sampler implementations into sampler.cc

src/sampler.cc

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__) \
+    || defined(__NetBSD__) || defined(__sun)

[Sven Panne, 2013/04/15 07:08:40]

In general, I'd like to move towards feature-based #ifdefs, not some obscure
combination of platform #ifdefs. In this case, I think the intention is
something like HAVE_UCONTEXT_H. It would nice if we could #define this somewhere
(even directly here, perhaps somewhere else later), and then use it like:

#if HAVE_UCONTEXT_H
...
#include <ucontext.h>
#endif

The same would be good for other #ifdefs here and elsewhere. We don't need to do
this in a single step now, but we should keep this in mind as a general goal
where we want to go: Have no platform #ifdefs sprinkled through all the code,
just some easy, readable combinations of feautre-based ones.

We can discuss how and where to define those feature-based #defines later, there
are various ways to do this with various pros and cons, e.g.:

 * Central "config-<platform>.h" headers with all #defines together

 * Feature-base #defines computed from platform-based #defines in the places
which need them.

 * Doing it via the build system.

We don't need to decide now, we can easily refactor this later depending on our
needs.

[yurys, 2013/04/15 11:37:55]

I'd first merge all implementations and have them in one file and after that
introduce capability defines you mentioned. WDYT?

+
+#include <errno.h>
+#include <pthread.h>
+#include <signal.h>
+#include <sys/time.h>
+#include <sys/syscall.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+#endif
+
+// GLibc on ARM defines mcontext_t has a typedef for 'struct sigcontext'.
+// Old versions of the C library <signal.h> didn't define the type.
+#if defined(__ANDROID__) && !defined(__BIONIC_HAVE_UCONTEXT_T) && \
+    defined(__arm__) && !defined(__BIONIC_HAVE_STRUCT_SIGCONTEXT)
+#include <asm/sigcontext.h>
+#endif
+
+#include "v8.h"
+
+#include "log.h"
+#include "platform.h"
+#include "simulator.h"
+#include "v8threads.h"
+
+
+namespace v8 {
+namespace internal {
+
+
+#if defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__) \
+    || defined(__NetBSD__) || defined(__sun)
+
+#if defined(__ANDROID__) && !defined(__BIONIC_HAVE_UCONTEXT_T)
+
+// Not all versions of Android's C library provide ucontext_t.
+// Detect this and provide custom but compatible definitions. Note that these
+// follow the GLibc naming convention to access register values from
+// mcontext_t.
+//
+// See http://code.google.com/p/android/issues/detail?id=34784
+
+#if defined(__arm__)
+
+typedef struct sigcontext mcontext_t;
+
+typedef struct ucontext {
+  uint32_t uc_flags;
+  struct ucontext* uc_link;
+  stack_t uc_stack;
+  mcontext_t uc_mcontext;
+  // Other fields are not used by V8, don't define them here.
+} ucontext_t;
+
+#elif defined(__mips__)
+// MIPS version of sigcontext, for Android bionic.
+typedef struct {
+  uint32_t regmask;
+  uint32_t status;
+  uint64_t pc;
+  uint64_t gregs[32];
+  uint64_t fpregs[32];
+  uint32_t acx;
+  uint32_t fpc_csr;
+  uint32_t fpc_eir;
+  uint32_t used_math;
+  uint32_t dsp;
+  uint64_t mdhi;
+  uint64_t mdlo;
+  uint32_t hi1;
+  uint32_t lo1;
+  uint32_t hi2;
+  uint32_t lo2;
+  uint32_t hi3;
+  uint32_t lo3;
+} mcontext_t;
+
+typedef struct ucontext {
+  uint32_t uc_flags;
+  struct ucontext* uc_link;
+  stack_t uc_stack;
+  mcontext_t uc_mcontext;
+  // Other fields are not used by V8, don't define them here.
+} ucontext_t;
+
+#elif defined(__i386__)
+// x86 version for Android.
+typedef struct {
+  uint32_t gregs[19];
+  void* fpregs;
+  uint32_t oldmask;
+  uint32_t cr2;
+} mcontext_t;
+
+typedef uint32_t kernel_sigset_t[2];  // x86 kernel uses 64-bit signal masks
+typedef struct ucontext {
+  uint32_t uc_flags;
+  struct ucontext* uc_link;
+  stack_t uc_stack;
+  mcontext_t uc_mcontext;
+  // Other fields are not used by V8, don't define them here.
+} ucontext_t;
+enum { REG_EBP = 6, REG_ESP = 7, REG_EIP = 14 };
+#endif
+
+#endif  // __ANDROID__ && !defined(__BIONIC_HAVE_UCONTEXT_T)
+
+
+static pthread_t GetThreadID() {
+#if defined(__ANDROID__)
+  // Android's C library provides gettid(2).
+  return gettid();
+#elif defined(__linux__)
+  // Glibc doesn't provide a wrapper for gettid(2).
+  return syscall(SYS_gettid);
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
+    || defined(__sun)
+  return pthread_self();
+#endif
+}
+
+
+class Sampler::PlatformData : public Malloced {
+ public:
+  PlatformData()
+      : vm_tid_(GetThreadID()),
+        profiled_thread_id_(ThreadId::Current()) {}
+
+  pthread_t vm_tid() const { return vm_tid_; }
+  ThreadId profiled_thread_id() { return profiled_thread_id_; }
+
+ private:
+  pthread_t vm_tid_;
+  ThreadId profiled_thread_id_;
+};
+
+
+static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
+#if defined(__native_client__)
+  // As Native Client does not support signal handling, profiling
+  // is disabled.
+  return;
+#else
+  USE(info);
+  if (signal != SIGPROF) return;
+  Isolate* isolate = Isolate::UncheckedCurrent();
+  if (isolate == NULL || !isolate->IsInitialized() || !isolate->IsInUse()) {
+    // We require a fully initialized and entered isolate.
+    return;
+  }
+  if (v8::Locker::IsActive() &&
+      !isolate->thread_manager()->IsLockedByCurrentThread()) {
+    return;
+  }
+
+  Sampler* sampler = isolate->logger()->sampler();
+  if (sampler == NULL || !sampler->IsActive()) return;
+
+#if defined(USE_SIMULATOR)
+#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
+  ThreadId thread_id = sampler->platform_data()->profiled_thread_id();
+  Isolate::PerIsolateThreadData* per_thread_data = isolate->
+      FindPerThreadDataForThread(thread_id);
+  if (!per_thread_data) return;
+  Simulator* sim = per_thread_data->simulator();
+  // Check if there is active simulator before allocating TickSample.
+  if (!sim) return;
+#endif
+#endif  // USE_SIMULATOR
+
+  TickSample sample_obj;
+  TickSample* sample = isolate->cpu_profiler()->TickSampleEvent();
+  if (sample == NULL) sample = &sample_obj;
+
+#if defined(USE_SIMULATOR)
+#if V8_TARGET_ARCH_ARM
+  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
+  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
+  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::r11));
+#elif V8_TARGET_ARCH_MIPS
+  sample->pc = reinterpret_cast<Address>(sim->get_register(Simulator::pc));
+  sample->sp = reinterpret_cast<Address>(sim->get_register(Simulator::sp));
+  sample->fp = reinterpret_cast<Address>(sim->get_register(Simulator::fp));
+#endif  // V8_TARGET_ARCH_*
+#else
+  // Extracting the sample from the context is extremely machine dependent.
+  ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
+  mcontext_t& mcontext = ucontext->uc_mcontext;
+  sample->state = isolate->current_vm_state();
+#if defined(__linux__)
+#if V8_HOST_ARCH_IA32
+  sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_EIP]);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_ESP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_EBP]);
+#elif V8_HOST_ARCH_X64
+  sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_RIP]);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_RSP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_RBP]);
+#elif V8_HOST_ARCH_ARM
+#if defined(__GLIBC__) && !defined(__UCLIBC__) && \
+    (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
+  // Old GLibc ARM versions used a gregs[] array to access the register
+  // values from mcontext_t.
+  sample->pc = reinterpret_cast<Address>(mcontext.gregs[R15]);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[R13]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[R11]);
+#else
+  sample->pc = reinterpret_cast<Address>(mcontext.arm_pc);
+  sample->sp = reinterpret_cast<Address>(mcontext.arm_sp);
+  sample->fp = reinterpret_cast<Address>(mcontext.arm_fp);
+#endif  // defined(__GLIBC__) && !defined(__UCLIBC__) &&
+        // (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
+#elif V8_HOST_ARCH_MIPS
+  sample->pc = reinterpret_cast<Address>(mcontext.pc);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[29]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[30]);
+#endif  // V8_HOST_ARCH_*
+#elif defined(__FreeBSD__)
+#if V8_HOST_ARCH_IA32
+  sample->pc = reinterpret_cast<Address>(mcontext.mc_eip);
+  sample->sp = reinterpret_cast<Address>(mcontext.mc_esp);
+  sample->fp = reinterpret_cast<Address>(mcontext.mc_ebp);
+#elif V8_HOST_ARCH_X64
+  sample->pc = reinterpret_cast<Address>(mcontext.mc_rip);
+  sample->sp = reinterpret_cast<Address>(mcontext.mc_rsp);
+  sample->fp = reinterpret_cast<Address>(mcontext.mc_rbp);
+#elif V8_HOST_ARCH_ARM
+  sample->pc = reinterpret_cast<Address>(mcontext.mc_r15);
+  sample->sp = reinterpret_cast<Address>(mcontext.mc_r13);
+  sample->fp = reinterpret_cast<Address>(mcontext.mc_r11);
+#endif  // V8_HOST_ARCH_*
+#elif defined(__NetBSD__)
+#if V8_HOST_ARCH_IA32
+  sample->pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_EIP]);
+  sample->sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_ESP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_EBP]);
+#elif V8_HOST_ARCH_X64
+  sample->pc = reinterpret_cast<Address>(mcontext.__gregs[_REG_RIP]);
+  sample->sp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RSP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.__gregs[_REG_RBP]);
+#endif  // V8_HOST_ARCH_*
+#elif defined(__OpenBSD__)
+  USE(mcontext);
+#if V8_HOST_ARCH_IA32
+  sample->pc = reinterpret_cast<Address>(ucontext->sc_eip);
+  sample->sp = reinterpret_cast<Address>(ucontext->sc_esp);
+  sample->fp = reinterpret_cast<Address>(ucontext->sc_ebp);
+#elif V8_HOST_ARCH_X64
+  sample->pc = reinterpret_cast<Address>(ucontext->sc_rip);
+  sample->sp = reinterpret_cast<Address>(ucontext->sc_rsp);
+  sample->fp = reinterpret_cast<Address>(ucontext->sc_rbp);
+#endif  // V8_HOST_ARCH_*
+#elif defined(__sun)
+  sample->pc = reinterpret_cast<Address>(mcontext.gregs[REG_PC]);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[REG_SP]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[REG_FP]);
+#endif  // __sun
+#endif  // USE_SIMULATOR
+
+  sampler->SampleStack(sample);
+  sampler->Tick(sample);
+#endif  // __native_client__
+}
+
+
+class SignalSender : public Thread {
+ public:
+  static const int kSignalSenderStackSize = 64 * KB;
+
+  explicit SignalSender(int interval)
+      : Thread(Thread::Options("SignalSender", kSignalSenderStackSize)),
+        vm_tgid_(getpid()),
+        interval_(interval) {}
+
+  static void SetUp() { if (!mutex_) mutex_ = OS::CreateMutex(); }
+  static void TearDown() { delete mutex_; }
+
+  static void InstallSignalHandler() {
+    struct sigaction sa;
+    sa.sa_sigaction = ProfilerSignalHandler;
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = SA_RESTART | SA_SIGINFO;
+    signal_handler_installed_ =
+        (sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
+  }
+
+  static void RestoreSignalHandler() {
+    if (signal_handler_installed_) {
+      sigaction(SIGPROF, &old_signal_handler_, 0);
+      signal_handler_installed_ = false;
+    }
+  }
+
+  static void AddActiveSampler(Sampler* sampler) {
+    ScopedLock lock(mutex_);
+    SamplerRegistry::AddActiveSampler(sampler);
+    if (instance_ == NULL) {
+      // Start a thread that will send SIGPROF signal to VM threads,
+      // when CPU profiling will be enabled.
+      instance_ = new SignalSender(sampler->interval());
+      instance_->StartSynchronously();
+    } else {
+      ASSERT(instance_->interval_ == sampler->interval());
+    }
+  }
+
+  static void RemoveActiveSampler(Sampler* sampler) {
+    ScopedLock lock(mutex_);
+    SamplerRegistry::RemoveActiveSampler(sampler);
+    if (SamplerRegistry::GetState() == SamplerRegistry::HAS_NO_SAMPLERS) {
+      instance_->Join();
+      delete instance_;
+      instance_ = NULL;
+      RestoreSignalHandler();
+    }
+  }
+
+  // Implement Thread::Run().
+  virtual void Run() {
+    SamplerRegistry::State state;
+    while ((state = SamplerRegistry::GetState()) !=
+           SamplerRegistry::HAS_NO_SAMPLERS) {
+      // When CPU profiling is enabled both JavaScript and C++ code is
+      // profiled. We must not suspend.
+      if (state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS) {
+        if (!signal_handler_installed_) InstallSignalHandler();
+        SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this);
+      } else {
+        if (signal_handler_installed_) RestoreSignalHandler();
+      }
+      Sleep();  // TODO(svenpanne) Figure out if OS:Sleep(interval_) is enough.
+    }
+  }
+
+  static void DoCpuProfile(Sampler* sampler, void* raw_sender) {
+    if (!sampler->IsProfiling()) return;
+    SignalSender* sender = reinterpret_cast<SignalSender*>(raw_sender);
+    sender->SendProfilingSignal(sampler->platform_data()->vm_tid());
+  }
+
+  void SendProfilingSignal(int tid) {
+    if (!signal_handler_installed_) return;
+    // Glibc doesn't provide a wrapper for tgkill(2).
+#if defined(ANDROID)

[Sven Panne, 2013/04/15 07:08:40]

Just another good example for feautre-based #ifdefs:

#if HAVE_PTHREAD_KILL
...
#else
...
#endif

Regarding the different constant, an idea might be:

#ifndef SYS_tgkill
#deinfe SYS_tgkill __NR_tgkill
#endif

Hmmm, or *does* Android have pthread_kill and we don't use it for some reason? I
don't know, but it would be good to find out and document it here if it is the
case. USE_PTHREAD_KILL is probably a better name than HAVE_PTHREAD_KILL then.

[yurys, 2013/04/15 11:37:55]

Let's do this in a separate change?

+    syscall(__NR_tgkill, vm_tgid_, tid, SIGPROF);
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
+    || defined(__sun)
+    pthread_kill(tid, SIGPROF);
+#else
+    int result = syscall(SYS_tgkill, vm_tgid_, tid, SIGPROF);
+    USE(result);
+    ASSERT(result == 0);

[Sven Panne, 2013/04/15 07:08:40]

Do we really want to assert this here and ignore the return value on Android? I
am not sure if this intentional.

[yurys, 2013/04/15 11:37:55]

I have no idea whether it was intentional or not but I'd prefer to keep the
number of potentially breaking changes minimal during the refactoring. We can
easily unify implementations later.

+#endif
+  }
+
+  void Sleep() {
+    // Convert ms to us and subtract 100 us to compensate delays
+    // occuring during signal delivery.
+    useconds_t interval = interval_ * 1000 - 100;
+#if defined(ANDROID)
+    usleep(interval);
+#else
+    int result = usleep(interval);
+#ifdef DEBUG
+    if (result != 0 && errno != EINTR) {
+      fprintf(stderr,
+              "SignalSender usleep error; interval = %u, errno = %d\n",
+              interval,
+              errno);
+      ASSERT(result == 0 || errno == EINTR);
+    }
+#endif  // DEBUG
+    USE(result);
+#endif  // ANDROID
+  }
+
+  const int vm_tgid_;
+  const int interval_;
+
+  // Protects the process wide state below.
+  static Mutex* mutex_;
+  static SignalSender* instance_;
+  static bool signal_handler_installed_;
+  static struct sigaction old_signal_handler_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SignalSender);
+};
+
+
+Mutex* SignalSender::mutex_ = NULL;
+SignalSender* SignalSender::instance_ = NULL;
+struct sigaction SignalSender::old_signal_handler_;
+bool SignalSender::signal_handler_installed_ = false;
+
+
+void Sampler::SetUp() {
+  SignalSender::SetUp();
+}
+
+
+void Sampler::TearDown() {
+  SignalSender::TearDown();
+}
+
+
+Sampler::Sampler(Isolate* isolate, int interval)
+    : isolate_(isolate),
+      interval_(interval),
+      profiling_(false),
+      active_(false),
+      samples_taken_(0) {
+  data_ = new PlatformData;
+}
+
+
+Sampler::~Sampler() {
+  ASSERT(!IsActive());
+  delete data_;
+}
+
+void Sampler::SampleStack(TickSample* sample) {
+  StackTracer::Trace(isolate_, sample);
+  if (++samples_taken_ < 0) samples_taken_ = 0;
+}
+
+void Sampler::Start() {
+  ASSERT(!IsActive());
+  SetActive(true);
+  SignalSender::AddActiveSampler(this);
+}
+
+
+void Sampler::Stop() {
+  ASSERT(IsActive());
+  SignalSender::RemoveActiveSampler(this);
+  SetActive(false);
+}
+
+#else

[Sven Panne, 2013/04/15 07:08:40]

Just out of curiosity: Do we need this dummy section at all? What would go wrong
if we just used the code above? It would be good if we could reduce the #ifdef
logic as much as possible.

[yurys, 2013/04/15 11:37:55]

I will remove this section when Mac and Win implementations are merged. The
problem here is that the thread class is called SignalSender on *NIX platforms
and SamplerThread on the rest.

+
+void Sampler::SetUp() {
+}
+
+
+void Sampler::TearDown() {
+}
+
+#endif  // __linux__ || _*BSD__ || __sun
+
+} }  // namespace v8::internal