Simplify ProfLazyMode test on Linux.

Instead of installing signal handler, count samples taken.

Review URL: http://codereview.chromium.org/5325003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5891 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/log.cc

@@ -194,11 +194,6 @@ class Ticker: public Sampler {
 
   ~Ticker() { if (IsActive()) Stop(); }
 
-  virtual void SampleStack(TickSample* sample) {
-    ASSERT(IsSynchronous());
-    StackTracer::Trace(sample);
-  }
-
   virtual void Tick(TickSample* sample) {
     if (profiler_) profiler_->Insert(sample);
     if (window_) window_->AddState(sample->state);
@@ -224,6 +219,12 @@ class Ticker: public Sampler {
     if (!window_ && IsActive()) Stop();
   }
 
+ protected:
+  virtual void DoSampleStack(TickSample* sample) {
+    ASSERT(IsSynchronous());
+    StackTracer::Trace(sample);
+  }
+
  private:
   SlidingStateWindow* window_;
   Profiler* profiler_;

src/platform-freebsd.cc

@@ -620,7 +620,8 @@ Sampler::Sampler(int interval, bool profiling)
     : interval_(interval),
       profiling_(profiling),
       synchronous_(profiling),
-      active_(false) {
+      active_(false),
+      samples_taken_(0) {
   data_ = new PlatformData();
 }
 

src/platform-linux.cc

@@ -865,7 +865,8 @@ Sampler::Sampler(int interval, bool profiling)
     : interval_(interval),
       profiling_(profiling),
       synchronous_(profiling),
-      active_(false) {
+      active_(false),
+      samples_taken_(0) {
   data_ = new PlatformData(this);
 }
 

src/platform-macos.cc

@@ -634,7 +634,8 @@ Sampler::Sampler(int interval, bool profiling)
     : interval_(interval),
       profiling_(profiling),
       synchronous_(profiling),
-      active_(false) {
+      active_(false),
+      samples_taken_(0) {
   data_ = new PlatformData(this);
 }
 

src/platform-openbsd.cc

@@ -572,7 +572,11 @@ class Sampler::PlatformData : public Malloced {
 
 
 Sampler::Sampler(int interval, bool profiling)
-    : interval_(interval), profiling_(profiling), active_(false) {
+    : interval_(interval),
+      profiling_(profiling),
+      synchronous_(profiling),
+      active_(false),
+      samples_taken_(0) {
   data_ = new PlatformData();
 }
 

src/platform-solaris.cc

@@ -605,7 +605,8 @@ Sampler::Sampler(int interval, bool profiling)
     : interval_(interval),
       profiling_(profiling),
       synchronous_(profiling),
-      active_(false) {
+      active_(false),
+      samples_taken_(0) {
   data_ = new PlatformData();
 }
 

src/platform-win32.cc

@@ -1905,7 +1905,8 @@ Sampler::Sampler(int interval, bool profiling)
     : interval_(interval),
       profiling_(profiling),
       synchronous_(profiling),
-      active_(false) {
+      active_(false),
+      samples_taken_(0) {
   data_ = new PlatformData(this);
 }
 

src/platform.h

@@ -554,11 +554,14 @@ class TickSample {
 class Sampler {
  public:
   // Initialize sampler.
-  explicit Sampler(int interval, bool profiling);
+  Sampler(int interval, bool profiling);
   virtual ~Sampler();
 
   // Performs stack sampling.
-  virtual void SampleStack(TickSample* sample) = 0;
+  void SampleStack(TickSample* sample) {
+    DoSampleStack(sample);
+    IncSamplesTaken();
+  }
 
   // This method is called for each sampling period with the current
   // program counter.
@@ -580,14 +583,24 @@ class Sampler {
   // Whether the sampler is running (that is, consumes resources).
   bool IsActive() const { return active_; }
 
+  // Used in tests to make sure that stack sampling is performed.
+  int samples_taken() const { return samples_taken_; }
+  void ResetSamplesTaken() { samples_taken_ = 0; }
+
   class PlatformData;
 
+ protected:
+  virtual void DoSampleStack(TickSample* sample) = 0;
+
  private:
+  void IncSamplesTaken() { if (++samples_taken_ < 0) samples_taken_ = 0; }
+
   const int interval_;
   const bool profiling_;
   const bool synchronous_;
   bool active_;
   PlatformData* data_;  // Platform specific data.
+  int samples_taken_;  // Counts stack samples taken.
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
 };
 

test/cctest/test-log.cc

@@ -139,6 +139,12 @@ namespace internal {
 class LoggerTestHelper : public AllStatic {
  public:
   static bool IsSamplerActive() { return Logger::IsProfilerSamplerActive(); }
+  static void ResetSamplesTaken() {
+    reinterpret_cast<Sampler*>(Logger::ticker_)->ResetSamplesTaken();
+  }
+  static bool has_samples_taken() {
+    return reinterpret_cast<Sampler*>(Logger::ticker_)->samples_taken() > 0;
+  }
 };
 
 }  // namespace v8::internal
@@ -147,24 +153,6 @@ class LoggerTestHelper : public AllStatic {
 using v8::internal::LoggerTestHelper;
 
 
-// Under Linux, we need to check if signals were delivered to avoid false
-// positives.  Under other platforms profiling is done via a high-priority
-// thread, so this case never happen.
-static bool was_sigprof_received = true;
-#ifdef __linux__
-
-struct sigaction old_sigprof_handler;
-pthread_t our_thread;
-
-static void SigProfSignalHandler(int signal, siginfo_t* info, void* context) {
-  if (signal != SIGPROF || !pthread_equal(pthread_self(), our_thread)) return;
-  was_sigprof_received = true;
-  old_sigprof_handler.sa_sigaction(signal, info, context);
-}
-
-#endif  // __linux__
-
-
 namespace {
 
 class ScopedLoggerInitializer {
@@ -258,6 +246,9 @@ class LogBufferMatcher {
 
 
 static void CheckThatProfilerWorks(LogBufferMatcher* matcher) {
+  CHECK(!LoggerTestHelper::IsSamplerActive());
+  LoggerTestHelper::ResetSamplesTaken();
+
   Logger::ResumeProfiler(v8::PROFILER_MODULE_CPU, 0);
   CHECK(LoggerTestHelper::IsSamplerActive());
 
@@ -266,19 +257,6 @@ static void CheckThatProfilerWorks(LogBufferMatcher* matcher) {
   const char* code_creation = "\ncode-creation,";  // eq. to /^code-creation,/
   CHECK_NE(NULL, matcher->Find(code_creation));
 
-#ifdef __linux__
-  // Intercept SIGPROF handler to make sure that the test process
-  // had received it. Under load, system can defer it causing test failure.
-  // It is important to execute this after 'ResumeProfiler'.
-  our_thread = pthread_self();
-  was_sigprof_received = false;
-  struct sigaction sa;
-  sa.sa_sigaction = SigProfSignalHandler;
-  sigemptyset(&sa.sa_mask);
-  sa.sa_flags = SA_SIGINFO;
-  CHECK_EQ(0, sigaction(SIGPROF, &sa, &old_sigprof_handler));
-#endif  // __linux__
-
   // Force compiler to generate new code by parametrizing source.
   EmbeddedVector<char, 100> script_src;
   i::OS::SNPrintF(script_src,
@@ -306,7 +284,7 @@ static void CheckThatProfilerWorks(LogBufferMatcher* matcher) {
   CHECK_NE(NULL, matcher->Find(code_creation));
   const char* tick = "\ntick,";
   const bool ticks_found = matcher->Find(tick) != NULL;
-  CHECK_EQ(was_sigprof_received, ticks_found);
+  CHECK_EQ(LoggerTestHelper::has_samples_taken(), ticks_found);
 }