Reland "[cpu-profiler] Add more logging to find flaky failure"

This is a reland of 138bcfc3

Fixed all the data races and ran TSAN locally to confirm.

Original change's description:
> [cpu-profiler] Add more logging to find flaky failure
>
> There is a flaky 5x failure in the tree which I can't reproduce locally.
> This extra logging will help flush out what the problem is.
>
> Bug: v8:8649
>
> Change-Id: If36d2ce0f4feb398d7d746d69b417bb55a714422
> Reviewed-on: https://chromium-review.googlesource.com/c/1402787
> Commit-Queue: Peter Marshall <petermarshall@chromium.org>
> Reviewed-by: Camillo Bruni <cbruni@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58796}

Bug: v8:8649
Change-Id: I53e293ef85a54d4b2b39aa3b980832031201aa0c
Reviewed-on: https://chromium-review.googlesource.com/c/1411633
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58833}

src/libsampler/DEPS

 include_rules = [
   "+include",
   "-src",
+  "+src/flags.h",
   "+src/base",
   "+src/libsampler",
 ]
\ No newline at end of file

src/libsampler/sampler.cc

@@ -63,6 +63,8 @@ typedef zx_arm64_general_regs_t zx_thread_state_general_regs_t;
 #include "src/base/atomic-utils.h"
 #include "src/base/hashmap.h"
 #include "src/base/platform/platform.h"
+// TODO(petermarshall): Remove when cpu profiler logging is no longer needed
+#include "src/flags.h"
 
 #if V8_OS_ANDROID && !defined(__BIONIC_HAVE_UCONTEXT_T)
 
@@ -265,6 +267,10 @@ class SamplerManager {
   void RemoveSampler(Sampler* sampler) {
     AtomicGuard atomic_guard(&samplers_access_counter_);
     DCHECK(sampler->IsActive() || sampler->IsRegistered());
+
+    if (i::FLAG_cpu_profiler_logging) {
+      printf("SamplerManager RemoveSampler: signals: %d\n", signals_);
+    }
     // Remove sampler from map.
     pthread_t thread_id = sampler->platform_data()->vm_tid();
     void* thread_key = ThreadKey(thread_id);
@@ -289,6 +295,7 @@ class SamplerManager {
   void DoSample(const v8::RegisterState& state) {
     AtomicGuard atomic_guard(&SamplerManager::samplers_access_counter_, false);
     if (!atomic_guard.is_success()) return;
+    signals_++;
     pthread_t thread_id = pthread_self();
     base::HashMap::Entry* entry =
         sampler_map_.Lookup(ThreadKey(thread_id), ThreadHash(thread_id));
@@ -314,6 +321,7 @@ class SamplerManager {
  private:
   base::HashMap sampler_map_;
   static AtomicMutex samplers_access_counter_;
+  int signals_ = 0;
 };
 
 AtomicMutex SamplerManager::samplers_access_counter_;
@@ -435,7 +443,6 @@ int SignalHandler::client_count_ = 0;
 struct sigaction SignalHandler::old_signal_handler_;
 bool SignalHandler::signal_handler_installed_ = false;
 
-
 void SignalHandler::HandleProfilerSignal(int signal, siginfo_t* info,
                                          void* context) {
   USE(info);
@@ -627,6 +634,9 @@ void Sampler::UnregisterIfRegistered() {
 Sampler::~Sampler() {
   DCHECK(!IsActive());
   DCHECK(!IsRegistered());
+  if (i::FLAG_cpu_profiler_logging && samples_ != 0) {
+    printf("~Sampler: samples = %d\n", samples_);
+  }
   delete data_;
 }
 
@@ -668,6 +678,7 @@ void Sampler::DecreaseProfilingDepth() {
 #if defined(USE_SIGNALS)
 
 void Sampler::DoSample() {
+  samples_++;
   if (!SignalHandler::Installed()) return;
   if (!IsActive() && !IsRegistered()) {
     SamplerManager::instance()->AddSampler(this);

src/libsampler/sampler.h

@@ -100,6 +100,7 @@ class Sampler {
   base::Atomic32 active_;
   base::Atomic32 registered_;
   PlatformData* data_;  // Platform specific data.
+  int samples_ = 0;
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
 };
 

src/profiler/cpu-profiler.cc

@@ -28,10 +28,16 @@ class CpuSampler : public sampler::Sampler {
   CpuSampler(Isolate* isolate, SamplingEventsProcessor* processor)
       : sampler::Sampler(reinterpret_cast<v8::Isolate*>(isolate)),
         processor_(processor) {}
+  ~CpuSampler() {
+    if (i::FLAG_cpu_profiler_logging) {
+      printf("~CpuSampler: samples_: %d\n", samples_);
+    }
+  }
 
   void SampleStack(const v8::RegisterState& regs) override {
     TickSample* sample = processor_->StartTickSample();
     if (sample == nullptr) return;
+    samples_++;
     Isolate* isolate = reinterpret_cast<Isolate*>(this->isolate());
     sample->Init(isolate, regs, TickSample::kIncludeCEntryFrame, true);
     if (is_counting_samples_ && !sample->timestamp.IsNull()) {
@@ -43,6 +49,7 @@ class CpuSampler : public sampler::Sampler {
 
  private:
   SamplingEventsProcessor* processor_;
+  int samples_ = 0;
 };
 
 ProfilerEventsProcessor::ProfilerEventsProcessor(Isolate* isolate,
@@ -407,6 +414,9 @@ void CpuProfiler::StartProcessorIfNotStarted() {
 CpuProfile* CpuProfiler::StopProfiling(const char* title) {
   if (!is_profiling_) return nullptr;
   StopProcessorIfLastProfile(title);
+  if (i::FLAG_cpu_profiler_logging) {
+    PrintF("StopProfiling: samples = %d\n", generator_->samples_);
+  }
   return profiles_->StopProfiling(title);
 }
 

src/profiler/profile-generator.cc

@@ -783,6 +783,7 @@ void ProfileGenerator::RecordTickSample(const TickSample& sample) {
   if (FLAG_cpu_profiler_logging) {
     PrintF("RecordTickSample: ");
     sample.print();
+    samples_++;
   }
 
   if (sample.pc != nullptr) {

src/profiler/profile-generator.h

@@ -463,10 +463,16 @@ class CpuProfilesCollection {
 class ProfileGenerator {
  public:
   explicit ProfileGenerator(CpuProfilesCollection* profiles);
+  ~ProfileGenerator() {
+    if (FLAG_cpu_profiler_logging) {
+      PrintF("~ProfileGenerator: samples = %d\n", samples_);
+    }
+  }
 
   void RecordTickSample(const TickSample& sample);
 
   CodeMap* code_map() { return &code_map_; }
+  int samples_ = 0;
 
  private:
   CodeEntry* FindEntry(Address address);