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::Code* GetFunctionCodeFromHeap(i::Isolate* isolate,
+                                        const char* name) {
+  CHECK_NE(NULL, isolate);
+  i::Heap* heap = isolate->heap();
+  CHECK_NE(NULL, heap);
+
+  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
+      "Logger::LogCompiledFunctions");

[yurys, 2014/08/08 08:13:23]

"GetFunctionCodeFromHeap"

+
+  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)
+          return sfi->code();
+    }
+  }
+
+  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();
+  CpuProfiler* profiler = isolate->cpu_profiler();
+  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"
+    "    var n = 100*1000;\n"
+    "    while(n > 1) {\n"
+    "      n--;\n"
+    "      this.mmm += n * n * n;\n"
+    "    }\n"
+    "  }\n"
+    "})(this)\n", foo_name);

[yurys, 2014/08/08 08:13:23]

'this' passed as timeout looks like an error.

+
+  // Compile the source. The compiled functions with relocation info are
+  // located in the heap.
+  CompileRun(source.start());
+
+  // The profiler consumes code creation events for all compiled functions
+  // found in the heap.
+  profiler->StartProfiling("", false);
+
+  // Enqueue the tick events to add 'foo' function to the profile.
+  i::Code* foo_code = GetFunctionCodeFromHeap(isolate, foo_name);
+  CHECK_NE(NULL, foo_code);
+  i::Address address = foo_code->instruction_start();
+  CHECK_NE(NULL, address);
+  EnqueueTickSampleEvent(profiler->processor(), address);
+  v8::base::OS::Sleep(100);  // Ensure that a new node is added to the profile.

[yurys, 2014/08/08 08:13:23]

We need to use some explicit event instead of Sleep. I believe calling
profiler->StopProfiling below should be enough as it should trigger processing
of all enqueued events.

+
+  // Get a code entry for 'foo' function.
+  ProfileGenerator* generator = profiler->generator();
+  CodeEntry* foo = generator->code_map()->FindEntry(address);

[yurys, 2014/08/08 08:13:23]

This is not thread-safe as code_map is used on the processor thread.

It should be enough to add a few fake events into the queue, stop profiling and
check that resulting tree reflects corresponding hit counts.

+  CHECK_NE(NULL, foo);
+
+  CpuProfile* profile = profiler->StopProfiling("");
+  CHECK_NE(NULL, profile);
+
+  // Firstly, check the underlying code entry for 'foo' function.
+  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());
+
+  // Secondly, check the hit source lines are accessible 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());
 }