Extend CPU profiler with mapping ticks to source lines

test/cctest/test-cpu-profiler.cc

 // Copyright 2010 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
@@ skipping 1046 matching lines @@
   CheckChildrenNames(root, names);
 
   const v8::CpuProfileNode* startNode =
       GetChild(env->GetIsolate(), root, "start");
   GetChild(env->GetIsolate(), startNode, "foo");
 
   profile->Delete();
 }
 
 
+static i::SharedFunctionInfo* GetFunctionInfoFromHeap(i::Isolate* isolate,
+    const char* name) {
+    CHECK_NE(NULL, isolate);
+    i::Heap* heap = isolate->heap();
+    CHECK_NE(NULL, heap);
+
+    heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
+        "GetFunctionInfoFromHeap");
+
+    i::HandleScope scope(isolate);
+    i::HeapIterator iterator(heap);
+    i::DisallowHeapAllocation no_gc;
+
+    // Iterate the heap to find shared function info objects.
+    for (i::HeapObject* obj = iterator.next();
+        obj != NULL;
+        obj = iterator.next()) {
+        if (!obj->IsSharedFunctionInfo()) continue;
+        i::SharedFunctionInfo* sfi = i::SharedFunctionInfo::cast(obj);
+        if (sfi->is_compiled()
+            && (!sfi->script()->IsScript()
+            || i::Script::cast(sfi->script())->HasValidSource())) {
+            i::Handle<i::String> func_name(sfi->DebugName());
+            i::SmartArrayPointer<char> str =
+                sfi->DebugName()->ToCString(i::DISALLOW_NULLS,
+                i::ROBUST_STRING_TRAVERSAL);
+            if (strcmp(str.get(), name) == 0)

[alph, 2014/08/11 12:18:15]

It's better to make a v8 heap string out of 'name' using v8::String::NewFromUtf8
so you can compare two heap strings instead.
This way you won't need to flatten each string in the heap to make the
comparison.

+                return sfi;
+        }
+    }
+
+    return NULL;
+}
+
+
+// This tests checks distribution of the samples through the source lines.
+TEST(TickLines) {
+  CcTest::InitializeVM();
+  LocalContext env;
+  i::Isolate* isolate = CcTest::i_isolate();
+  i::Factory* factory = isolate->factory();
+  i::HandleScope scope(isolate);
+
+  i::EmbeddedVector<char, 512> source;
+  const char* foo_name = "foo";
+  i::SNPrintF(source,
+    "(function %s(timeout) {\n"
+    "  this.mmm = 0;\n"
+    "  var start = Date.now();\n"
+    "  while (Date.now() - start < timeout) {\n"

[alph, 2014/08/11 12:18:15]

This test bound to be flaky as it depends on the timeouts.

Instead if you want the foo function surely got into profile, make a call to
startProfiling right out of foo. startProfiling always takes the first sample at
its invocation point. See BoundFunctionCall test for example.

+    "    var n = 100*1000;\n"
+    "    while(n > 1) {\n"
+    "      n--;\n"
+    "      this.mmm += n * n * n;\n"
+    "    }\n"
+    "  }\n"
+    "})(%d)\n", foo_name, 100);
+
+  // Compile the source. The compiled functions with relocation info are
+  // located in the heap.
+  CompileRun(source.start());
+
+  i::SharedFunctionInfo* shared = GetFunctionInfoFromHeap(isolate, foo_name);

[alph, 2014/08/11 12:18:15]

You can get the JSFunction object out of global context after CompileRun instead
of iterating the whole heap. See CreateCode function body above for example.

+  CHECK_NE(NULL, shared);
+  i::Code* foo_code = shared->code();
+  CHECK_NE(NULL, foo_code);
+
+  CpuProfilesCollection* profiles = new CpuProfilesCollection(isolate->heap());
+  profiles->StartProfiling("", false);
+  ProfileGenerator generator(profiles);
+  SmartPointer<ProfilerEventsProcessor> processor(new ProfilerEventsProcessor(
+      &generator, NULL, v8::base::TimeDelta::FromMicroseconds(100)));
+  processor->Start();
+  CpuProfiler profiler(isolate, profiles, &generator, processor.get());
+
+  // Enqueue code creation events.
+  i::Handle<i::String> str = factory->NewStringFromAsciiChecked(foo_name);
+  int line = 1;
+  int column = 1;
+  profiler.CodeCreateEvent(i::Logger::FUNCTION_TAG,
+                           foo_code,
+                           shared,
+                           NULL,
+                           *str,
+                           line,
+                           column);
+
+  // Enqueue a tick event to enable code events processing.
+  EnqueueTickSampleEvent(processor.get(), foo_code->address());
+
+  processor->StopSynchronously();
+
+  CpuProfile* profile = profiles->StopProfiling("");
+  CHECK_NE(NULL, profile);
+
+  // Check the state of profile generator.
+  CodeEntry* foo = generator.code_map()->FindEntry(foo_code->address());
+  CHECK_NE(NULL, foo);
+  CHECK_EQ(foo_name, foo->name());
+  const i::JITLineInfoTable* foo_line_info = foo->line_info();
+  CHECK_NE(NULL, foo_line_info);
+  CHECK_EQ(false, foo_line_info->Empty());
+
+  // Check the hit source lines using V8 Public APIs.
+  const i::ProfileTree* tree = profile->top_down();
+  ProfileNode* root = tree->root();
+  CHECK_NE(NULL, root);
+  ProfileNode* foo_node = root->FindChild(foo);
+  CHECK_NE(NULL, foo_node);
+
+  // Add 10 faked ticks to source line #5.
+  int hit_line = 5;
+  int hit_count = 10;
+  for (int i = 0; i < hit_count; i++)
+    foo_node->IncrementLineTicks(hit_line);
+
+  unsigned int line_count = foo_node->GetHitLineCount();
+  CHECK_EQ(2, line_count);  // Expect two hit source lines - #1 and #5.
+  ScopedVector<v8::CpuProfileNode::LineTick> entries(line_count);
+  CHECK_EQ(true, foo_node->GetLineTicks(&entries[0], line_count));
+  int value = 0;
+  for (int i = 0; i < entries.length(); i++)
+    if (entries[i].line == hit_line) {
+      value = entries[i].hit_count;
+      break;
+    }
+  CHECK_EQ(hit_count, value);
+}
+
+
 static const char* call_function_test_source = "function bar(iterations) {\n"
 "}\n"
 "function start(duration) {\n"
 "  var start = Date.now();\n"
 "  while (Date.now() - start < duration) {\n"
 "    try {\n"
 "      bar.call(this, 10 * 1000);\n"
 "    } catch(e) {}\n"
 "  }\n"
 "}";
@@ skipping 599 matching lines @@
   inner_profile = NULL;
   CHECK_EQ(0, iprofiler->GetProfilesCount());
 
   v8::CpuProfile* outer_profile = profiler->StopProfiling(outer);
   CHECK(outer_profile);
   CHECK_EQ(1, iprofiler->GetProfilesCount());
   outer_profile->Delete();
   outer_profile = NULL;
   CHECK_EQ(0, iprofiler->GetProfilesCount());
 }