// Copyright 2012 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.
// Platform specific code for FreeBSD goes here. For the POSIX comaptible parts
// the implementation is in platform-posix.cc.
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/types.h>
#include <sys/ucontext.h>
#include <stdlib.h>
#include <sys/types.h> // mmap & munmap
#include <sys/mman.h> // mmap & munmap
#include <sys/stat.h> // open
#include <sys/fcntl.h> // open
#include <unistd.h> // getpagesize
// If you don't have execinfo.h then you need devel/libexecinfo from ports.
#include <execinfo.h> // backtrace, backtrace_symbols
#include <strings.h> // index
#include <errno.h>
#include <stdarg.h>
#include <limits.h>
#undef MAP_TYPE
#include "v8.h"
#include "v8threads.h"
#include "platform-posix.h"
#include "platform.h"
#include "vm-state-inl.h"
namespace v8 {
namespace internal {
// 0 is never a valid thread id on FreeBSD since tids and pids share a
// name space and pid 0 is used to kill the group (see man 2 kill).
static const pthread_t kNoThread = (pthread_t) 0;
double ceiling(double x) {
// Correct as on OS X
if (-1.0 < x && x < 0.0) {
return -0.0;
} else {
return ceil(x);
}
}
static Mutex* limit_mutex = NULL;
void OS::SetUp() {
// Seed the random number generator.
// Convert the current time to a 64-bit integer first, before converting it
// to an unsigned. Going directly can cause an overflow and the seed to be
// set to all ones. The seed will be identical for different instances that
// call this setup code within the same millisecond.
uint64_t seed = static_cast<uint64_t>(TimeCurrentMillis());
srandom(static_cast<unsigned int>(seed));
limit_mutex = CreateMutex();
}
void OS::PostSetUp() {
// Math functions depend on CPU features therefore they are initialized after
// CPU.
MathSetup();
}
void OS::ReleaseStore(volatile AtomicWord* ptr, AtomicWord value) {
__asm__ __volatile__("" : : : "memory");
*ptr = value;
}
uint64_t OS::CpuFeaturesImpliedByPlatform() {
return 0; // FreeBSD runs on anything.
}
int OS::ActivationFrameAlignment() {
// 16 byte alignment on FreeBSD
return 16;
}
const char* OS::LocalTimezone(double time) {
if (isnan(time)) return "";
time_t tv = static_cast<time_t>(floor(time/msPerSecond));
struct tm* t = localtime(&tv);
if (NULL == t) return "";
return t->tm_zone;
}
double OS::LocalTimeOffset() {
time_t tv = time(NULL);
struct tm* t = localtime(&tv);
// tm_gmtoff includes any daylight savings offset, so subtract it.
return static_cast<double>(t->tm_gmtoff * msPerSecond -
(t->tm_isdst > 0 ? 3600 * msPerSecond : 0));
}
// We keep the lowest and highest addresses mapped as a quick way of
// determining that pointers are outside the heap (used mostly in assertions
// and verification). The estimate is conservative, i.e., not all addresses in
// 'allocated' space are actually allocated to our heap. The range is
// [lowest, highest), inclusive on the low and and exclusive on the high end.
static void* lowest_ever_allocated = reinterpret_cast<void*>(-1);
static void* highest_ever_allocated = reinterpret_cast<void*>(0);
static void UpdateAllocatedSpaceLimits(void* address, int size) {
ASSERT(limit_mutex != NULL);
ScopedLock lock(limit_mutex);
lowest_ever_allocated = Min(lowest_ever_allocated, address);
highest_ever_allocated =
Max(highest_ever_allocated,
reinterpret_cast<void*>(reinterpret_cast<char*>(address) + size));
}
bool OS::IsOutsideAllocatedSpace(void* address) {
return address < lowest_ever_allocated || address >= highest_ever_allocated;
}
size_t OS::AllocateAlignment() {
return getpagesize();
}
void* OS::Allocate(const size_t requested,
size_t* allocated,
bool executable) {
const size_t msize = RoundUp(requested, getpagesize());
int prot = PROT_READ | PROT_WRITE | (executable ? PROT_EXEC : 0);
void* mbase = mmap(NULL, msize, prot, MAP_PRIVATE | MAP_ANON, -1, 0);
if (mbase == MAP_FAILED) {
LOG(ISOLATE, StringEvent("OS::Allocate", "mmap failed"));
return NULL;
}
*allocated = msize;
UpdateAllocatedSpaceLimits(mbase, msize);
return mbase;
}
void OS::Free(void* buf, const size_t length) {
// TODO(1240712): munmap has a return value which is ignored here.
int result = munmap(buf, length);
USE(result);
ASSERT(result == 0);
}
void OS::Sleep(int milliseconds) {
unsigned int ms = static_cast<unsigned int>(milliseconds);
usleep(1000 * ms);
}
void OS::Abort() {
// Redirect to std abort to signal abnormal program termination.
abort();
}
void OS::DebugBreak() {
#if (defined(__arm__) || defined(__thumb__))
# if defined(CAN_USE_ARMV5_INSTRUCTIONS)
asm("bkpt 0");
# endif
#else
asm("int $3");
#endif
}
class PosixMemoryMappedFile : public OS::MemoryMappedFile {
public:
PosixMemoryMappedFile(FILE* file, void* memory, int size)
: file_(file), memory_(memory), size_(size) { }
virtual ~PosixMemoryMappedFile();
virtual void* memory() { return memory_; }
virtual int size() { return size_; }
private:
FILE* file_;
void* memory_;
int size_;
};
OS::MemoryMappedFile* OS::MemoryMappedFile::open(const char* name) {
FILE* file = fopen(name, "r+");
if (file == NULL) return NULL;
fseek(file, 0, SEEK_END);
int size = ftell(file);
void* memory =
mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
return new PosixMemoryMappedFile(file, memory, size);
}
OS::MemoryMappedFile* OS::MemoryMappedFile::create(const char* name, int size,
void* initial) {
FILE* file = fopen(name, "w+");
if (file == NULL) return NULL;
int result = fwrite(initial, size, 1, file);
if (result < 1) {
fclose(file);
return NULL;
}
void* memory =
mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
return new PosixMemoryMappedFile(file, memory, size);
}
PosixMemoryMappedFile::~PosixMemoryMappedFile() {
if (memory_) munmap(memory_, size_);
fclose(file_);
}
static unsigned StringToLong(char* buffer) {
return static_cast<unsigned>(strtol(buffer, NULL, 16)); // NOLINT
}
void OS::LogSharedLibraryAddresses() {
static const int MAP_LENGTH = 1024;
int fd = open("/proc/self/maps", O_RDONLY);
if (fd < 0) return;
while (true) {
char addr_buffer[11];
addr_buffer[0] = '0';
addr_buffer[1] = 'x';
addr_buffer[10] = 0;
int result = read(fd, addr_buffer + 2, 8);
if (result < 8) break;
unsigned start = StringToLong(addr_buffer);
result = read(fd, addr_buffer + 2, 1);
if (result < 1) break;
if (addr_buffer[2] != '-') break;
result = read(fd, addr_buffer + 2, 8);
if (result < 8) break;
unsigned end = StringToLong(addr_buffer);
char buffer[MAP_LENGTH];
int bytes_read = -1;
do {
bytes_read++;
if (bytes_read >= MAP_LENGTH - 1)
break;
result = read(fd, buffer + bytes_read, 1);
if (result < 1) break;
} while (buffer[bytes_read] != '\n');
buffer[bytes_read] = 0;
// Ignore mappings that are not executable.
if (buffer[3] != 'x') continue;
char* start_of_path = index(buffer, '/');
// There may be no filename in this line. Skip to next.
if (start_of_path == NULL) continue;
buffer[bytes_read] = 0;
LOG(i::Isolate::Current(), SharedLibraryEvent(start_of_path, start, end));
}
close(fd);
}
void OS::SignalCodeMovingGC() {
}
int OS::StackWalk(Vector<OS::StackFrame> frames) {
int frames_size = frames.length();
ScopedVector<void*> addresses(frames_size);
int frames_count = backtrace(addresses.start(), frames_size);
char** symbols = backtrace_symbols(addresses.start(), frames_count);
if (symbols == NULL) {
return kStackWalkError;
}
for (int i = 0; i < frames_count; i++) {
frames[i].address = addresses[i];
// Format a text representation of the frame based on the information
// available.
SNPrintF(MutableCStrVector(frames[i].text, kStackWalkMaxTextLen),
"%s",
symbols[i]);
// Make sure line termination is in place.
frames[i].text[kStackWalkMaxTextLen - 1] = '\0';
}
free(symbols);
return frames_count;
}
// Constants used for mmap.
static const int kMmapFd = -1;
static const int kMmapFdOffset = 0;
VirtualMemory::VirtualMemory() : address_(NULL), size_(0) { }
VirtualMemory::VirtualMemory(size_t size) {
address_ = ReserveRegion(size);
size_ = size;
}
VirtualMemory::VirtualMemory(size_t size, size_t alignment)
: address_(NULL), size_(0) {
ASSERT(IsAligned(alignment, static_cast<intptr_t>(OS::AllocateAlignment())));
size_t request_size = RoundUp(size + alignment,
static_cast<intptr_t>(OS::AllocateAlignment()));
void* reservation = mmap(OS::GetRandomMmapAddr(),
request_size,
PROT_NONE,
MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
kMmapFd,
kMmapFdOffset);
if (reservation == MAP_FAILED) return;
Address base = static_cast<Address>(reservation);
Address aligned_base = RoundUp(base, alignment);
ASSERT_LE(base, aligned_base);
// Unmap extra memory reserved before and after the desired block.
if (aligned_base != base) {
size_t prefix_size = static_cast<size_t>(aligned_base - base);
OS::Free(base, prefix_size);
request_size -= prefix_size;
}
size_t aligned_size = RoundUp(size, OS::AllocateAlignment());
ASSERT_LE(aligned_size, request_size);
if (aligned_size != request_size) {
size_t suffix_size = request_size - aligned_size;
OS::Free(aligned_base + aligned_size, suffix_size);
request_size -= suffix_size;
}
ASSERT(aligned_size == request_size);
address_ = static_cast<void*>(aligned_base);
size_ = aligned_size;
}
VirtualMemory::~VirtualMemory() {
if (IsReserved()) {
bool result = ReleaseRegion(address(), size());
ASSERT(result);
USE(result);
}
}
bool VirtualMemory::IsReserved() {
return address_ != NULL;
}
void VirtualMemory::Reset() {
address_ = NULL;
size_ = 0;
}
bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) {
return CommitRegion(address, size, is_executable);
}
bool VirtualMemory::Uncommit(void* address, size_t size) {
return UncommitRegion(address, size);
}
bool VirtualMemory::Guard(void* address) {
OS::Guard(address, OS::CommitPageSize());
return true;
}
void* VirtualMemory::ReserveRegion(size_t size) {
void* result = mmap(OS::GetRandomMmapAddr(),
size,
PROT_NONE,
MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
kMmapFd,
kMmapFdOffset);
if (result == MAP_FAILED) return NULL;
return result;
}
bool VirtualMemory::CommitRegion(void* base, size_t size, bool is_executable) {
int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
if (MAP_FAILED == mmap(base,
size,
prot,
MAP_PRIVATE | MAP_ANON | MAP_FIXED,
kMmapFd,
kMmapFdOffset)) {
return false;
}
UpdateAllocatedSpaceLimits(base, size);
return true;
}
bool VirtualMemory::UncommitRegion(void* base, size_t size) {
return mmap(base,
size,
PROT_NONE,
MAP_PRIVATE | MAP_ANON | MAP_NORESERVE | MAP_FIXED,
kMmapFd,
kMmapFdOffset) != MAP_FAILED;
}
bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
return munmap(base, size) == 0;
}
class Thread::PlatformData : public Malloced {
public:
pthread_t thread_; // Thread handle for pthread.
};
Thread::Thread(const Options& options)
: data_(new PlatformData),
stack_size_(options.stack_size()) {
set_name(options.name());
}
Thread::~Thread() {
delete data_;
}
static void* ThreadEntry(void* arg) {
Thread* thread = reinterpret_cast<Thread*>(arg);
// This is also initialized by the first argument to pthread_create() but we
// don't know which thread will run first (the original thread or the new
// one) so we initialize it here too.
thread->data()->thread_ = pthread_self();
ASSERT(thread->data()->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(&data_->thread_, attr_ptr, ThreadEntry, this);
ASSERT(data_->thread_ != kNoThread);
}
void Thread::Join() {
pthread_join(data_->thread_, NULL);
}
Thread::LocalStorageKey Thread::CreateThreadLocalKey() {
pthread_key_t key;
int result = pthread_key_create(&key, NULL);
USE(result);
ASSERT(result == 0);
return static_cast<LocalStorageKey>(key);
}
void Thread::DeleteThreadLocalKey(LocalStorageKey key) {
pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
int result = pthread_key_delete(pthread_key);
USE(result);
ASSERT(result == 0);
}
void* Thread::GetThreadLocal(LocalStorageKey key) {
pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
return pthread_getspecific(pthread_key);
}
void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
pthread_key_t pthread_key = static_cast<pthread_key_t>(key);
pthread_setspecific(pthread_key, value);
}
void Thread::YieldCPU() {
sched_yield();
}
class FreeBSDMutex : public Mutex {
public:
FreeBSDMutex() {
pthread_mutexattr_t attrs;
int result = pthread_mutexattr_init(&attrs);
ASSERT(result == 0);
result = pthread_mutexattr_settype(&attrs, PTHREAD_MUTEX_RECURSIVE);
ASSERT(result == 0);
result = pthread_mutex_init(&mutex_, &attrs);
ASSERT(result == 0);
}
virtual ~FreeBSDMutex() { pthread_mutex_destroy(&mutex_); }
virtual int Lock() {
int result = pthread_mutex_lock(&mutex_);
return result;
}
virtual int Unlock() {
int result = pthread_mutex_unlock(&mutex_);
return result;
}
virtual bool TryLock() {
int result = pthread_mutex_trylock(&mutex_);
// Return false if the lock is busy and locking failed.
if (result == EBUSY) {
return false;
}
ASSERT(result == 0); // Verify no other errors.
return true;
}
private:
pthread_mutex_t mutex_; // Pthread mutex for POSIX platforms.
};
Mutex* OS::CreateMutex() {
return new FreeBSDMutex();
}
class FreeBSDSemaphore : public Semaphore {
public:
explicit FreeBSDSemaphore(int count) { sem_init(&sem_, 0, count); }
virtual ~FreeBSDSemaphore() { sem_destroy(&sem_); }
virtual void Wait();
virtual bool Wait(int timeout);
virtual void Signal() { sem_post(&sem_); }
private:
sem_t sem_;
};
void FreeBSDSemaphore::Wait() {
while (true) {
int result = sem_wait(&sem_);
if (result == 0) return; // Successfully got semaphore.
CHECK(result == -1 && errno == EINTR); // Signal caused spurious wakeup.
}
}
bool FreeBSDSemaphore::Wait(int timeout) {
const long kOneSecondMicros = 1000000; // NOLINT
// Split timeout into second and nanosecond parts.
struct timeval delta;
delta.tv_usec = timeout % kOneSecondMicros;
delta.tv_sec = timeout / kOneSecondMicros;
struct timeval current_time;
// Get the current time.
if (gettimeofday(¤t_time, NULL) == -1) {
return false;
}
// Calculate time for end of timeout.
struct timeval end_time;
timeradd(¤t_time, &delta, &end_time);
struct timespec ts;
TIMEVAL_TO_TIMESPEC(&end_time, &ts);
while (true) {
int result = sem_timedwait(&sem_, &ts);
if (result == 0) return true; // Successfully got semaphore.
if (result == -1 && errno == ETIMEDOUT) return false; // Timeout.
CHECK(result == -1 && errno == EINTR); // Signal caused spurious wakeup.
}
}
Semaphore* OS::CreateSemaphore(int count) {
return new FreeBSDSemaphore(count);
}
static pthread_t GetThreadID() {
pthread_t thread_id = pthread_self();
return thread_id;
}
class Sampler::PlatformData : public Malloced {
public:
PlatformData() : vm_tid_(GetThreadID()) {}
pthread_t vm_tid() const { return vm_tid_; }
private:
pthread_t vm_tid_;
};
static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
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;
TickSample sample_obj;
TickSample* sample = CpuProfiler::TickSampleEvent(isolate);
if (sample == NULL) sample = &sample_obj;
// 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 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
sampler->SampleStack(sample);
sampler->Tick(sample);
}
class SignalSender : public Thread {
public:
enum SleepInterval {
HALF_INTERVAL,
FULL_INTERVAL
};
static const int kSignalSenderStackSize = 64 * KB;
explicit SignalSender(int interval)
: Thread(Thread::Options("SignalSender", kSignalSenderStackSize)),
interval_(interval) {}
static void AddActiveSampler(Sampler* sampler) {
ScopedLock lock(mutex_.Pointer());
SamplerRegistry::AddActiveSampler(sampler);
if (instance_ == NULL) {
// Install a signal handler.
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);
// Start a thread that sends SIGPROF signal to VM threads.
instance_ = new SignalSender(sampler->interval());
instance_->Start();
} else {
ASSERT(instance_->interval_ == sampler->interval());
}
}
static void RemoveActiveSampler(Sampler* sampler) {
ScopedLock lock(mutex_.Pointer());
SamplerRegistry::RemoveActiveSampler(sampler);
if (SamplerRegistry::GetState() == SamplerRegistry::HAS_NO_SAMPLERS) {
RuntimeProfiler::StopRuntimeProfilerThreadBeforeShutdown(instance_);
delete instance_;
instance_ = NULL;
// Restore the old signal handler.
if (signal_handler_installed_) {
sigaction(SIGPROF, &old_signal_handler_, 0);
signal_handler_installed_ = false;
}
}
}
// Implement Thread::Run().
virtual void Run() {
SamplerRegistry::State state;
while ((state = SamplerRegistry::GetState()) !=
SamplerRegistry::HAS_NO_SAMPLERS) {
bool cpu_profiling_enabled =
(state == SamplerRegistry::HAS_CPU_PROFILING_SAMPLERS);
bool runtime_profiler_enabled = RuntimeProfiler::IsEnabled();
// When CPU profiling is enabled both JavaScript and C++ code is
// profiled. We must not suspend.
if (!cpu_profiling_enabled) {
if (rate_limiter_.SuspendIfNecessary()) continue;
}
if (cpu_profiling_enabled && runtime_profiler_enabled) {
if (!SamplerRegistry::IterateActiveSamplers(&DoCpuProfile, this)) {
return;
}
Sleep(HALF_INTERVAL);
if (!SamplerRegistry::IterateActiveSamplers(&DoRuntimeProfile, NULL)) {
return;
}
Sleep(HALF_INTERVAL);
} else {
if (cpu_profiling_enabled) {
if (!SamplerRegistry::IterateActiveSamplers(&DoCpuProfile,
this)) {
return;
}
}
if (runtime_profiler_enabled) {
if (!SamplerRegistry::IterateActiveSamplers(&DoRuntimeProfile,
NULL)) {
return;
}
}
Sleep(FULL_INTERVAL);
}
}
}
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());
}
static void DoRuntimeProfile(Sampler* sampler, void* ignored) {
if (!sampler->isolate()->IsInitialized()) return;
sampler->isolate()->runtime_profiler()->NotifyTick();
}
void SendProfilingSignal(pthread_t tid) {
if (!signal_handler_installed_) return;
pthread_kill(tid, SIGPROF);
}
void Sleep(SleepInterval full_or_half) {
// Convert ms to us and subtract 100 us to compensate delays
// occuring during signal delivery.
useconds_t interval = interval_ * 1000 - 100;
if (full_or_half == HALF_INTERVAL) interval /= 2;
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
USE(result);
}
const int interval_;
RuntimeProfilerRateLimiter rate_limiter_;
// Protects the process wide state below.
static LazyMutex mutex_;
static SignalSender* instance_;
static bool signal_handler_installed_;
static struct sigaction old_signal_handler_;
private:
DISALLOW_COPY_AND_ASSIGN(SignalSender);
};
LazyMutex SignalSender::mutex_ = LAZY_MUTEX_INITIALIZER;
SignalSender* SignalSender::instance_ = NULL;
struct sigaction SignalSender::old_signal_handler_;
bool SignalSender::signal_handler_installed_ = false;
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::Start() {
ASSERT(!IsActive());
SetActive(true);
SignalSender::AddActiveSampler(this);
}
void Sampler::Stop() {
ASSERT(IsActive());
SignalSender::RemoveActiveSampler(this);
SetActive(false);
}
} } // namespace v8::internal