CPU profiler: increase the max number of captured frames.

LOG=N
R=jkummerow@chromium.org, loislo@chromium.org, yurys@chromium.org

Review URL: https://codereview.chromium.org/357443003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21986 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/log.cc

@@ -1715,7 +1715,7 @@ void Logger::TickEvent(TickSample* sample, bool overflow) {
   if (overflow) {
     msg.Append(",overflow");
   }
-  for (int i = 0; i < sample->frames_count; ++i) {
+  for (unsigned i = 0; i < sample->frames_count; ++i) {
     msg.Append(',');
     msg.AppendAddress(sample->stack[i]);
   }

src/sampler.cc

@@ -596,7 +596,7 @@ DISABLE_ASAN void TickSample::Init(Isolate* isolate,
 
   SafeStackFrameIterator it(isolate, regs.fp, regs.sp, js_entry_sp);
   top_frame_type = it.top_frame_type();
-  int i = 0;
+  unsigned i = 0;
   while (!it.done() && i < TickSample::kMaxFramesCount) {
     stack[i++] = it.frame()->pc();
     it.Advance();

src/sampler.h

@@ -44,10 +44,11 @@ struct TickSample {
     Address tos;   // Top stack value (*sp).
     Address external_callback;
   };
-  static const int kMaxFramesCount = 64;
+  static const unsigned kMaxFramesCountLog2 = 8;
+  static const unsigned kMaxFramesCount = (1 << kMaxFramesCountLog2) - 1;
   Address stack[kMaxFramesCount];  // Call stack.
   TimeTicks timestamp;
-  int frames_count : 8;  // Number of captured frames.
+  unsigned frames_count : kMaxFramesCountLog2;  // Number of captured frames.
   bool has_external_callback : 1;
   StackFrame::Type top_frame_type : 4;
 };

test/cctest/test-cpu-profiler.cc

@@ -283,7 +283,7 @@ TEST(Issue1398) {
   sample->pc = code->address();
   sample->tos = 0;
   sample->frames_count = i::TickSample::kMaxFramesCount;
-  for (int i = 0; i < sample->frames_count; ++i) {
+  for (unsigned i = 0; i < sample->frames_count; ++i) {
     sample->stack[i] = code->address();
   }
   processor->FinishTickSample();
@@ -1248,6 +1248,72 @@ TEST(FunctionApplySample) {
 }
 
 
+static const char* cpu_profiler_deep_stack_test_source =
+"function foo(n) {\n"
+"  if (n)\n"
+"    foo(n - 1);\n"
+"  else\n"
+"    startProfiling('my_profile');\n"
+"}\n"
+"function start() {\n"
+"  foo(250);\n"
+"}\n";
+
+
+// Check a deep stack
+//
+// [Top down]:
+//    0  (root) 0 #1
+//    2    (program) 0 #2
+//    0    start 21 #3 no reason
+//    0      foo 21 #4 no reason
+//    0        foo 21 #5 no reason
+//                ....
+//    0          foo 21 #253 no reason
+//    1            startProfiling 0 #254
+TEST(CpuProfileDeepStack) {
+  v8::HandleScope scope(CcTest::isolate());
+  v8::Local<v8::Context> env = CcTest::NewContext(PROFILER_EXTENSION);
+  v8::Context::Scope context_scope(env);
+
+  v8::Script::Compile(v8::String::NewFromUtf8(
+      env->GetIsolate(), cpu_profiler_deep_stack_test_source))->Run();
+  v8::Local<v8::Function> function = v8::Local<v8::Function>::Cast(
+      env->Global()->Get(v8::String::NewFromUtf8(env->GetIsolate(), "start")));
+
+  v8::CpuProfiler* cpu_profiler = env->GetIsolate()->GetCpuProfiler();
+  v8::Local<v8::String> profile_name =
+      v8::String::NewFromUtf8(env->GetIsolate(), "my_profile");
+  function->Call(env->Global(), 0, NULL);
+  v8::CpuProfile* profile = cpu_profiler->StopProfiling(profile_name);
+  CHECK_NE(NULL, profile);
+  // Dump collected profile to have a better diagnostic in case of failure.
+  reinterpret_cast<i::CpuProfile*>(profile)->Print();
+
+  const v8::CpuProfileNode* root = profile->GetTopDownRoot();
+  {
+    ScopedVector<v8::Handle<v8::String> > names(3);
+    names[0] = v8::String::NewFromUtf8(
+        env->GetIsolate(), ProfileGenerator::kGarbageCollectorEntryName);
+    names[1] = v8::String::NewFromUtf8(env->GetIsolate(),
+                                       ProfileGenerator::kProgramEntryName);
+    names[2] = v8::String::NewFromUtf8(env->GetIsolate(), "start");
+    CheckChildrenNames(root, names);
+  }
+
+  const v8::CpuProfileNode* node =
+      GetChild(env->GetIsolate(), root, "start");
+  for (int i = 0; i < 250; ++i) {
+    node = GetChild(env->GetIsolate(), node, "foo");
+  }
+  // TODO(alph):
+  // In theory there must be one more 'foo' and a 'startProfiling' nodes,
+  // but due to unstable top frame extraction these might be missing.
+
+  profile->Delete();
+}
+
+
 static const char* js_native_js_test_source =
 "var is_profiling = false;\n"
 "function foo(iterations) {\n"

test/cctest/test-log-stack-tracer.cc

@@ -172,7 +172,7 @@ TEST(CFromJSStackTrace) {
   CHECK_EQ(FUNCTION_ADDR(i::TraceExtension::Trace), sample.external_callback);
 
   // Stack tracing will start from the first JS function, i.e. "JSFuncDoTrace"
-  int base = 0;
+  unsigned base = 0;
   CHECK_GT(sample.frames_count, base + 1);
 
   CHECK(IsAddressWithinFuncCode(
@@ -225,7 +225,7 @@ TEST(PureJSStackTrace) {
   CHECK_EQ(FUNCTION_ADDR(i::TraceExtension::JSTrace), sample.external_callback);
 
   // Stack sampling will start from the caller of JSFuncDoTrace, i.e. "JSTrace"
-  int base = 0;
+  unsigned base = 0;
   CHECK_GT(sample.frames_count, base + 1);
   CHECK(IsAddressWithinFuncCode(context, "JSTrace", sample.stack[base + 0]));
   CHECK(IsAddressWithinFuncCode(