Line data Source code
1 : // Copyright 2016 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : #include "src/libsampler/sampler.h"
6 :
7 : #ifdef USE_SIGNALS
8 :
9 : #include <errno.h>
10 : #include <pthread.h>
11 : #include <signal.h>
12 : #include <sys/time.h>
13 : #include <atomic>
14 :
15 : #if !V8_OS_QNX && !V8_OS_AIX
16 : #include <sys/syscall.h> // NOLINT
17 : #endif
18 :
19 : #if V8_OS_MACOSX
20 : #include <mach/mach.h>
21 : // OpenBSD doesn't have <ucontext.h>. ucontext_t lives in <signal.h>
22 : // and is a typedef for struct sigcontext. There is no uc_mcontext.
23 : #elif !V8_OS_OPENBSD
24 : #include <ucontext.h>
25 : #endif
26 :
27 : #include <unistd.h>
28 :
29 : #elif V8_OS_WIN || V8_OS_CYGWIN
30 :
31 : #include "src/base/win32-headers.h"
32 :
33 : #elif V8_OS_FUCHSIA
34 :
35 : #include <zircon/process.h>
36 : #include <zircon/syscalls.h>
37 : #include <zircon/syscalls/debug.h>
38 : #include <zircon/types.h>
39 :
40 : // TODO(wez): Remove this once the Fuchsia SDK has rolled.
41 : #if defined(ZX_THREAD_STATE_REGSET0)
42 : #define ZX_THREAD_STATE_GENERAL_REGS ZX_THREAD_STATE_REGSET0
43 : zx_status_t zx_thread_read_state(zx_handle_t h, uint32_t k, void* b, size_t l) {
44 : uint32_t dummy_out_len = 0;
45 : return zx_thread_read_state(h, k, b, static_cast<uint32_t>(l),
46 : &dummy_out_len);
47 : }
48 : #if defined(__x86_64__)
49 : typedef zx_x86_64_general_regs_t zx_thread_state_general_regs_t;
50 : #else
51 : typedef zx_arm64_general_regs_t zx_thread_state_general_regs_t;
52 : #endif
53 : #endif // !defined(ZX_THREAD_STATE_GENERAL_REGS)
54 :
55 : #endif
56 :
57 : #include <algorithm>
58 : #include <vector>
59 :
60 : #include "src/base/atomic-utils.h"
61 : #include "src/base/platform/platform.h"
62 :
63 : #if V8_OS_ANDROID && !defined(__BIONIC_HAVE_UCONTEXT_T)
64 :
65 : // Not all versions of Android's C library provide ucontext_t.
66 : // Detect this and provide custom but compatible definitions. Note that these
67 : // follow the GLibc naming convention to access register values from
68 : // mcontext_t.
69 : //
70 : // See http://code.google.com/p/android/issues/detail?id=34784
71 :
72 : #if defined(__arm__)
73 :
74 : typedef struct sigcontext mcontext_t;
75 :
76 : typedef struct ucontext {
77 : uint32_t uc_flags;
78 : struct ucontext* uc_link;
79 : stack_t uc_stack;
80 : mcontext_t uc_mcontext;
81 : // Other fields are not used by V8, don't define them here.
82 : } ucontext_t;
83 :
84 : #elif defined(__aarch64__)
85 :
86 : typedef struct sigcontext mcontext_t;
87 :
88 : typedef struct ucontext {
89 : uint64_t uc_flags;
90 : struct ucontext *uc_link;
91 : stack_t uc_stack;
92 : mcontext_t uc_mcontext;
93 : // Other fields are not used by V8, don't define them here.
94 : } ucontext_t;
95 :
96 : #elif defined(__mips__)
97 : // MIPS version of sigcontext, for Android bionic.
98 : typedef struct {
99 : uint32_t regmask;
100 : uint32_t status;
101 : uint64_t pc;
102 : uint64_t gregs[32];
103 : uint64_t fpregs[32];
104 : uint32_t acx;
105 : uint32_t fpc_csr;
106 : uint32_t fpc_eir;
107 : uint32_t used_math;
108 : uint32_t dsp;
109 : uint64_t mdhi;
110 : uint64_t mdlo;
111 : uint32_t hi1;
112 : uint32_t lo1;
113 : uint32_t hi2;
114 : uint32_t lo2;
115 : uint32_t hi3;
116 : uint32_t lo3;
117 : } mcontext_t;
118 :
119 : typedef struct ucontext {
120 : uint32_t uc_flags;
121 : struct ucontext* uc_link;
122 : stack_t uc_stack;
123 : mcontext_t uc_mcontext;
124 : // Other fields are not used by V8, don't define them here.
125 : } ucontext_t;
126 :
127 : #elif defined(__i386__)
128 : // x86 version for Android.
129 : typedef struct {
130 : uint32_t gregs[19];
131 : void* fpregs;
132 : uint32_t oldmask;
133 : uint32_t cr2;
134 : } mcontext_t;
135 :
136 : typedef uint32_t kernel_sigset_t[2]; // x86 kernel uses 64-bit signal masks
137 : typedef struct ucontext {
138 : uint32_t uc_flags;
139 : struct ucontext* uc_link;
140 : stack_t uc_stack;
141 : mcontext_t uc_mcontext;
142 : // Other fields are not used by V8, don't define them here.
143 : } ucontext_t;
144 : enum { REG_EBP = 6, REG_ESP = 7, REG_EIP = 14 };
145 :
146 : #elif defined(__x86_64__)
147 : // x64 version for Android.
148 : typedef struct {
149 : uint64_t gregs[23];
150 : void* fpregs;
151 : uint64_t __reserved1[8];
152 : } mcontext_t;
153 :
154 : typedef struct ucontext {
155 : uint64_t uc_flags;
156 : struct ucontext *uc_link;
157 : stack_t uc_stack;
158 : mcontext_t uc_mcontext;
159 : // Other fields are not used by V8, don't define them here.
160 : } ucontext_t;
161 : enum { REG_RBP = 10, REG_RSP = 15, REG_RIP = 16 };
162 : #endif
163 :
164 : #endif // V8_OS_ANDROID && !defined(__BIONIC_HAVE_UCONTEXT_T)
165 :
166 :
167 : namespace v8 {
168 : namespace sampler {
169 :
170 : #if defined(USE_SIGNALS)
171 :
172 28868 : AtomicGuard::AtomicGuard(AtomicMutex* atomic, bool is_blocking)
173 28868 : : atomic_(atomic), is_success_(false) {
174 28868 : do {
175 28868 : bool expected = false;
176 : // We have to use the strong version here for the case where is_blocking
177 : // is false, and we will only attempt the exchange once.
178 28868 : is_success_ = atomic->compare_exchange_strong(expected, true);
179 1539 : } while (is_blocking && !is_success_);
180 28868 : }
181 :
182 30 : AtomicGuard::~AtomicGuard() {
183 28868 : if (!is_success_) return;
184 28858 : atomic_->store(false);
185 30 : }
186 :
187 27339 : bool AtomicGuard::is_success() const { return is_success_; }
188 :
189 : class Sampler::PlatformData {
190 : public:
191 61816 : PlatformData() : vm_tid_(pthread_self()) {}
192 30427 : pthread_t vm_tid() const { return vm_tid_; }
193 :
194 : private:
195 : pthread_t vm_tid_;
196 : };
197 :
198 772 : void SamplerManager::AddSampler(Sampler* sampler) {
199 772 : AtomicGuard atomic_guard(&samplers_access_counter_);
200 : DCHECK(sampler->IsActive());
201 1544 : pthread_t thread_id = sampler->platform_data()->vm_tid();
202 : auto it = sampler_map_.find(thread_id);
203 772 : if (it == sampler_map_.end()) {
204 : SamplerList samplers;
205 757 : samplers.push_back(sampler);
206 : sampler_map_.emplace(thread_id, std::move(samplers));
207 : } else {
208 15 : SamplerList& samplers = it->second;
209 : auto it = std::find(samplers.begin(), samplers.end(), sampler);
210 15 : if (it == samplers.end()) samplers.push_back(sampler);
211 : }
212 772 : }
213 :
214 757 : void SamplerManager::RemoveSampler(Sampler* sampler) {
215 757 : AtomicGuard atomic_guard(&samplers_access_counter_);
216 : DCHECK(sampler->IsActive());
217 1514 : pthread_t thread_id = sampler->platform_data()->vm_tid();
218 : auto it = sampler_map_.find(thread_id);
219 : DCHECK_NE(it, sampler_map_.end());
220 757 : SamplerList& samplers = it->second;
221 : samplers.erase(std::remove(samplers.begin(), samplers.end(), sampler),
222 757 : samplers.end());
223 757 : if (samplers.empty()) {
224 : sampler_map_.erase(it);
225 : }
226 757 : }
227 :
228 27309 : void SamplerManager::DoSample(const v8::RegisterState& state) {
229 27309 : AtomicGuard atomic_guard(&samplers_access_counter_, false);
230 27309 : if (!atomic_guard.is_success()) return;
231 27309 : pthread_t thread_id = pthread_self();
232 : auto it = sampler_map_.find(thread_id);
233 27309 : if (it == sampler_map_.end()) return;
234 : SamplerList& samplers = it->second;
235 :
236 109796 : for (Sampler* sampler : samplers) {
237 27886 : if (!sampler->ShouldRecordSample()) continue;
238 : Isolate* isolate = sampler->isolate();
239 : // We require a fully initialized and entered isolate.
240 27302 : if (isolate == nullptr || !isolate->IsInUse()) continue;
241 27296 : if (v8::Locker::IsActive() && !Locker::IsLocked(isolate)) continue;
242 27296 : sampler->SampleStack(state);
243 : }
244 : }
245 :
246 28813 : SamplerManager* SamplerManager::instance() {
247 28813 : static base::LeakyObject<SamplerManager> instance;
248 28813 : return instance.get();
249 : }
250 :
251 : #elif V8_OS_WIN || V8_OS_CYGWIN
252 :
253 : // ----------------------------------------------------------------------------
254 : // Win32 profiler support. On Cygwin we use the same sampler implementation as
255 : // on Win32.
256 :
257 : class Sampler::PlatformData {
258 : public:
259 : // Get a handle to the calling thread. This is the thread that we are
260 : // going to profile. We need to make a copy of the handle because we are
261 : // going to use it in the sampler thread. Using GetThreadHandle() will
262 : // not work in this case. We're using OpenThread because DuplicateHandle
263 : // for some reason doesn't work in Chrome's sandbox.
264 : PlatformData()
265 : : profiled_thread_(OpenThread(THREAD_GET_CONTEXT |
266 : THREAD_SUSPEND_RESUME |
267 : THREAD_QUERY_INFORMATION,
268 : false,
269 : GetCurrentThreadId())) {}
270 :
271 : ~PlatformData() {
272 : if (profiled_thread_ != nullptr) {
273 : CloseHandle(profiled_thread_);
274 : profiled_thread_ = nullptr;
275 : }
276 : }
277 :
278 : HANDLE profiled_thread() { return profiled_thread_; }
279 :
280 : private:
281 : HANDLE profiled_thread_;
282 : };
283 :
284 : #elif V8_OS_FUCHSIA
285 :
286 : class Sampler::PlatformData {
287 : public:
288 : PlatformData() {
289 : zx_handle_duplicate(zx_thread_self(), ZX_RIGHT_SAME_RIGHTS,
290 : &profiled_thread_);
291 : }
292 : ~PlatformData() {
293 : if (profiled_thread_ != ZX_HANDLE_INVALID) {
294 : zx_handle_close(profiled_thread_);
295 : profiled_thread_ = ZX_HANDLE_INVALID;
296 : }
297 : }
298 :
299 : zx_handle_t profiled_thread() { return profiled_thread_; }
300 :
301 : private:
302 : zx_handle_t profiled_thread_ = ZX_HANDLE_INVALID;
303 : };
304 :
305 : #endif // USE_SIGNALS
306 :
307 :
308 : #if defined(USE_SIGNALS)
309 : class SignalHandler {
310 : public:
311 757 : static void IncreaseSamplerCount() {
312 : base::MutexGuard lock_guard(mutex_.Pointer());
313 757 : if (++client_count_ == 1) Install();
314 757 : }
315 :
316 752 : static void DecreaseSamplerCount() {
317 : base::MutexGuard lock_guard(mutex_.Pointer());
318 752 : if (--client_count_ == 0) Restore();
319 752 : }
320 :
321 28898 : static bool Installed() {
322 : base::MutexGuard lock_guard(mutex_.Pointer());
323 57796 : return signal_handler_installed_;
324 : }
325 :
326 : private:
327 744 : static void Install() {
328 : struct sigaction sa;
329 744 : sa.sa_sigaction = &HandleProfilerSignal;
330 744 : sigemptyset(&sa.sa_mask);
331 : #if V8_OS_QNX
332 : sa.sa_flags = SA_SIGINFO;
333 : #else
334 744 : sa.sa_flags = SA_RESTART | SA_SIGINFO;
335 : #endif
336 : signal_handler_installed_ =
337 744 : (sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
338 744 : }
339 :
340 739 : static void Restore() {
341 739 : if (signal_handler_installed_) {
342 739 : sigaction(SIGPROF, &old_signal_handler_, nullptr);
343 739 : signal_handler_installed_ = false;
344 : }
345 739 : }
346 :
347 : static void FillRegisterState(void* context, RegisterState* regs);
348 : static void HandleProfilerSignal(int signal, siginfo_t* info, void* context);
349 :
350 : // Protects the process wide state below.
351 : static base::LazyMutex mutex_;
352 : static int client_count_;
353 : static bool signal_handler_installed_;
354 : static struct sigaction old_signal_handler_;
355 : };
356 :
357 : base::LazyMutex SignalHandler::mutex_ = LAZY_MUTEX_INITIALIZER;
358 : int SignalHandler::client_count_ = 0;
359 : struct sigaction SignalHandler::old_signal_handler_;
360 : bool SignalHandler::signal_handler_installed_ = false;
361 :
362 :
363 27294 : void SignalHandler::HandleProfilerSignal(int signal, siginfo_t* info,
364 : void* context) {
365 : USE(info);
366 27294 : if (signal != SIGPROF) return;
367 : v8::RegisterState state;
368 : FillRegisterState(context, &state);
369 27294 : SamplerManager::instance()->DoSample(state);
370 : }
371 :
372 0 : void SignalHandler::FillRegisterState(void* context, RegisterState* state) {
373 : // Extracting the sample from the context is extremely machine dependent.
374 : ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
375 : #if !(V8_OS_OPENBSD || (V8_OS_LINUX && (V8_HOST_ARCH_PPC || V8_HOST_ARCH_S390)))
376 : mcontext_t& mcontext = ucontext->uc_mcontext;
377 : #endif
378 : #if V8_OS_LINUX
379 : #if V8_HOST_ARCH_IA32
380 : state->pc = reinterpret_cast<void*>(mcontext.gregs[REG_EIP]);
381 : state->sp = reinterpret_cast<void*>(mcontext.gregs[REG_ESP]);
382 : state->fp = reinterpret_cast<void*>(mcontext.gregs[REG_EBP]);
383 : #elif V8_HOST_ARCH_X64
384 27294 : state->pc = reinterpret_cast<void*>(mcontext.gregs[REG_RIP]);
385 27294 : state->sp = reinterpret_cast<void*>(mcontext.gregs[REG_RSP]);
386 27294 : state->fp = reinterpret_cast<void*>(mcontext.gregs[REG_RBP]);
387 : #elif V8_HOST_ARCH_ARM
388 : #if V8_LIBC_GLIBC && !V8_GLIBC_PREREQ(2, 4)
389 : // Old GLibc ARM versions used a gregs[] array to access the register
390 : // values from mcontext_t.
391 : state->pc = reinterpret_cast<void*>(mcontext.gregs[R15]);
392 : state->sp = reinterpret_cast<void*>(mcontext.gregs[R13]);
393 : state->fp = reinterpret_cast<void*>(mcontext.gregs[R11]);
394 : #else
395 : state->pc = reinterpret_cast<void*>(mcontext.arm_pc);
396 : state->sp = reinterpret_cast<void*>(mcontext.arm_sp);
397 : state->fp = reinterpret_cast<void*>(mcontext.arm_fp);
398 : #endif // V8_LIBC_GLIBC && !V8_GLIBC_PREREQ(2, 4)
399 : #elif V8_HOST_ARCH_ARM64
400 : state->pc = reinterpret_cast<void*>(mcontext.pc);
401 : state->sp = reinterpret_cast<void*>(mcontext.sp);
402 : // FP is an alias for x29.
403 : state->fp = reinterpret_cast<void*>(mcontext.regs[29]);
404 : #elif V8_HOST_ARCH_MIPS
405 : state->pc = reinterpret_cast<void*>(mcontext.pc);
406 : state->sp = reinterpret_cast<void*>(mcontext.gregs[29]);
407 : state->fp = reinterpret_cast<void*>(mcontext.gregs[30]);
408 : #elif V8_HOST_ARCH_MIPS64
409 : state->pc = reinterpret_cast<void*>(mcontext.pc);
410 : state->sp = reinterpret_cast<void*>(mcontext.gregs[29]);
411 : state->fp = reinterpret_cast<void*>(mcontext.gregs[30]);
412 : #elif V8_HOST_ARCH_PPC
413 : #if V8_LIBC_GLIBC
414 : state->pc = reinterpret_cast<void*>(ucontext->uc_mcontext.regs->nip);
415 : state->sp =
416 : reinterpret_cast<void*>(ucontext->uc_mcontext.regs->gpr[PT_R1]);
417 : state->fp =
418 : reinterpret_cast<void*>(ucontext->uc_mcontext.regs->gpr[PT_R31]);
419 : #else
420 : // Some C libraries, notably Musl, define the regs member as a void pointer
421 : state->pc = reinterpret_cast<void*>(ucontext->uc_mcontext.gp_regs[32]);
422 : state->sp = reinterpret_cast<void*>(ucontext->uc_mcontext.gp_regs[1]);
423 : state->fp = reinterpret_cast<void*>(ucontext->uc_mcontext.gp_regs[31]);
424 : #endif
425 : #elif V8_HOST_ARCH_S390
426 : #if V8_TARGET_ARCH_32_BIT
427 : // 31-bit target will have bit 0 (MSB) of the PSW set to denote addressing
428 : // mode. This bit needs to be masked out to resolve actual address.
429 : state->pc =
430 : reinterpret_cast<void*>(ucontext->uc_mcontext.psw.addr & 0x7FFFFFFF);
431 : #else
432 : state->pc = reinterpret_cast<void*>(ucontext->uc_mcontext.psw.addr);
433 : #endif // V8_TARGET_ARCH_32_BIT
434 : state->sp = reinterpret_cast<void*>(ucontext->uc_mcontext.gregs[15]);
435 : state->fp = reinterpret_cast<void*>(ucontext->uc_mcontext.gregs[11]);
436 : #endif // V8_HOST_ARCH_*
437 : #elif V8_OS_MACOSX
438 : #if V8_HOST_ARCH_X64
439 : #if __DARWIN_UNIX03
440 : state->pc = reinterpret_cast<void*>(mcontext->__ss.__rip);
441 : state->sp = reinterpret_cast<void*>(mcontext->__ss.__rsp);
442 : state->fp = reinterpret_cast<void*>(mcontext->__ss.__rbp);
443 : #else // !__DARWIN_UNIX03
444 : state->pc = reinterpret_cast<void*>(mcontext->ss.rip);
445 : state->sp = reinterpret_cast<void*>(mcontext->ss.rsp);
446 : state->fp = reinterpret_cast<void*>(mcontext->ss.rbp);
447 : #endif // __DARWIN_UNIX03
448 : #elif V8_HOST_ARCH_IA32
449 : #if __DARWIN_UNIX03
450 : state->pc = reinterpret_cast<void*>(mcontext->__ss.__eip);
451 : state->sp = reinterpret_cast<void*>(mcontext->__ss.__esp);
452 : state->fp = reinterpret_cast<void*>(mcontext->__ss.__ebp);
453 : #else // !__DARWIN_UNIX03
454 : state->pc = reinterpret_cast<void*>(mcontext->ss.eip);
455 : state->sp = reinterpret_cast<void*>(mcontext->ss.esp);
456 : state->fp = reinterpret_cast<void*>(mcontext->ss.ebp);
457 : #endif // __DARWIN_UNIX03
458 : #endif // V8_HOST_ARCH_IA32
459 : #elif V8_OS_FREEBSD
460 : #if V8_HOST_ARCH_IA32
461 : state->pc = reinterpret_cast<void*>(mcontext.mc_eip);
462 : state->sp = reinterpret_cast<void*>(mcontext.mc_esp);
463 : state->fp = reinterpret_cast<void*>(mcontext.mc_ebp);
464 : #elif V8_HOST_ARCH_X64
465 : state->pc = reinterpret_cast<void*>(mcontext.mc_rip);
466 : state->sp = reinterpret_cast<void*>(mcontext.mc_rsp);
467 : state->fp = reinterpret_cast<void*>(mcontext.mc_rbp);
468 : #elif V8_HOST_ARCH_ARM
469 : state->pc = reinterpret_cast<void*>(mcontext.mc_r15);
470 : state->sp = reinterpret_cast<void*>(mcontext.mc_r13);
471 : state->fp = reinterpret_cast<void*>(mcontext.mc_r11);
472 : #endif // V8_HOST_ARCH_*
473 : #elif V8_OS_NETBSD
474 : #if V8_HOST_ARCH_IA32
475 : state->pc = reinterpret_cast<void*>(mcontext.__gregs[_REG_EIP]);
476 : state->sp = reinterpret_cast<void*>(mcontext.__gregs[_REG_ESP]);
477 : state->fp = reinterpret_cast<void*>(mcontext.__gregs[_REG_EBP]);
478 : #elif V8_HOST_ARCH_X64
479 : state->pc = reinterpret_cast<void*>(mcontext.__gregs[_REG_RIP]);
480 : state->sp = reinterpret_cast<void*>(mcontext.__gregs[_REG_RSP]);
481 : state->fp = reinterpret_cast<void*>(mcontext.__gregs[_REG_RBP]);
482 : #endif // V8_HOST_ARCH_*
483 : #elif V8_OS_OPENBSD
484 : #if V8_HOST_ARCH_IA32
485 : state->pc = reinterpret_cast<void*>(ucontext->sc_eip);
486 : state->sp = reinterpret_cast<void*>(ucontext->sc_esp);
487 : state->fp = reinterpret_cast<void*>(ucontext->sc_ebp);
488 : #elif V8_HOST_ARCH_X64
489 : state->pc = reinterpret_cast<void*>(ucontext->sc_rip);
490 : state->sp = reinterpret_cast<void*>(ucontext->sc_rsp);
491 : state->fp = reinterpret_cast<void*>(ucontext->sc_rbp);
492 : #endif // V8_HOST_ARCH_*
493 : #elif V8_OS_SOLARIS
494 : state->pc = reinterpret_cast<void*>(mcontext.gregs[REG_PC]);
495 : state->sp = reinterpret_cast<void*>(mcontext.gregs[REG_SP]);
496 : state->fp = reinterpret_cast<void*>(mcontext.gregs[REG_FP]);
497 : #elif V8_OS_QNX
498 : #if V8_HOST_ARCH_IA32
499 : state->pc = reinterpret_cast<void*>(mcontext.cpu.eip);
500 : state->sp = reinterpret_cast<void*>(mcontext.cpu.esp);
501 : state->fp = reinterpret_cast<void*>(mcontext.cpu.ebp);
502 : #elif V8_HOST_ARCH_ARM
503 : state->pc = reinterpret_cast<void*>(mcontext.cpu.gpr[ARM_REG_PC]);
504 : state->sp = reinterpret_cast<void*>(mcontext.cpu.gpr[ARM_REG_SP]);
505 : state->fp = reinterpret_cast<void*>(mcontext.cpu.gpr[ARM_REG_FP]);
506 : #endif // V8_HOST_ARCH_*
507 : #elif V8_OS_AIX
508 : state->pc = reinterpret_cast<void*>(mcontext.jmp_context.iar);
509 : state->sp = reinterpret_cast<void*>(mcontext.jmp_context.gpr[1]);
510 : state->fp = reinterpret_cast<void*>(mcontext.jmp_context.gpr[31]);
511 : #endif // V8_OS_AIX
512 0 : }
513 :
514 : #endif // USE_SIGNALS
515 :
516 61815 : Sampler::Sampler(Isolate* isolate)
517 123630 : : isolate_(isolate), data_(base::make_unique<PlatformData>()) {}
518 :
519 61796 : Sampler::~Sampler() {
520 : DCHECK(!IsActive());
521 61796 : }
522 :
523 757 : void Sampler::Start() {
524 : DCHECK(!IsActive());
525 : SetActive(true);
526 : #if defined(USE_SIGNALS)
527 757 : SignalHandler::IncreaseSamplerCount();
528 757 : SamplerManager::instance()->AddSampler(this);
529 : #endif
530 757 : }
531 :
532 752 : void Sampler::Stop() {
533 : #if defined(USE_SIGNALS)
534 752 : SamplerManager::instance()->RemoveSampler(this);
535 752 : SignalHandler::DecreaseSamplerCount();
536 : #endif
537 : DCHECK(IsActive());
538 : SetActive(false);
539 752 : }
540 :
541 : #if defined(USE_SIGNALS)
542 :
543 28898 : void Sampler::DoSample() {
544 57796 : if (!SignalHandler::Installed()) return;
545 : DCHECK(IsActive());
546 : SetShouldRecordSample();
547 28898 : pthread_kill(platform_data()->vm_tid(), SIGPROF);
548 : }
549 :
550 : #elif V8_OS_WIN || V8_OS_CYGWIN
551 :
552 : void Sampler::DoSample() {
553 : HANDLE profiled_thread = platform_data()->profiled_thread();
554 : if (profiled_thread == nullptr) return;
555 :
556 : const DWORD kSuspendFailed = static_cast<DWORD>(-1);
557 : if (SuspendThread(profiled_thread) == kSuspendFailed) return;
558 :
559 : // Context used for sampling the register state of the profiled thread.
560 : CONTEXT context;
561 : memset(&context, 0, sizeof(context));
562 : context.ContextFlags = CONTEXT_FULL;
563 : if (GetThreadContext(profiled_thread, &context) != 0) {
564 : v8::RegisterState state;
565 : #if V8_HOST_ARCH_X64
566 : state.pc = reinterpret_cast<void*>(context.Rip);
567 : state.sp = reinterpret_cast<void*>(context.Rsp);
568 : state.fp = reinterpret_cast<void*>(context.Rbp);
569 : #elif V8_HOST_ARCH_ARM64
570 : state.pc = reinterpret_cast<void*>(context.Pc);
571 : state.sp = reinterpret_cast<void*>(context.Sp);
572 : state.fp = reinterpret_cast<void*>(context.Fp);
573 : #else
574 : state.pc = reinterpret_cast<void*>(context.Eip);
575 : state.sp = reinterpret_cast<void*>(context.Esp);
576 : state.fp = reinterpret_cast<void*>(context.Ebp);
577 : #endif
578 : SampleStack(state);
579 : }
580 : ResumeThread(profiled_thread);
581 : }
582 :
583 : #elif V8_OS_FUCHSIA
584 :
585 : void Sampler::DoSample() {
586 : zx_handle_t profiled_thread = platform_data()->profiled_thread();
587 : if (profiled_thread == ZX_HANDLE_INVALID) return;
588 :
589 : zx_handle_t suspend_token = ZX_HANDLE_INVALID;
590 : if (zx_task_suspend_token(profiled_thread, &suspend_token) != ZX_OK) return;
591 :
592 : // Wait for the target thread to become suspended, or to exit.
593 : // TODO(wez): There is currently no suspension count for threads, so there
594 : // is a risk that some other caller resumes the thread in-between our suspend
595 : // and wait calls, causing us to miss the SUSPENDED signal. We apply a 100ms
596 : // deadline to protect against hanging the sampler thread in this case.
597 : zx_signals_t signals = 0;
598 : zx_status_t suspended = zx_object_wait_one(
599 : profiled_thread, ZX_THREAD_SUSPENDED | ZX_THREAD_TERMINATED,
600 : zx_deadline_after(ZX_MSEC(100)), &signals);
601 : if (suspended != ZX_OK || (signals & ZX_THREAD_SUSPENDED) == 0) {
602 : zx_handle_close(suspend_token);
603 : return;
604 : }
605 :
606 : // Fetch a copy of its "general register" states.
607 : zx_thread_state_general_regs_t thread_state = {};
608 : if (zx_thread_read_state(profiled_thread, ZX_THREAD_STATE_GENERAL_REGS,
609 : &thread_state, sizeof(thread_state)) == ZX_OK) {
610 : v8::RegisterState state;
611 : #if V8_HOST_ARCH_X64
612 : state.pc = reinterpret_cast<void*>(thread_state.rip);
613 : state.sp = reinterpret_cast<void*>(thread_state.rsp);
614 : state.fp = reinterpret_cast<void*>(thread_state.rbp);
615 : #elif V8_HOST_ARCH_ARM64
616 : state.pc = reinterpret_cast<void*>(thread_state.pc);
617 : state.sp = reinterpret_cast<void*>(thread_state.sp);
618 : state.fp = reinterpret_cast<void*>(thread_state.r[29]);
619 : #endif
620 : SampleStack(state);
621 : }
622 :
623 : zx_handle_close(suspend_token);
624 : }
625 :
626 : // TODO(wez): Remove this once the Fuchsia SDK has rolled.
627 : #if defined(ZX_THREAD_STATE_REGSET0)
628 : #undef ZX_THREAD_STATE_GENERAL_REGS
629 : #endif
630 :
631 : #endif // USE_SIGNALS
632 :
633 : } // namespace sampler
634 : } // namespace v8
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