[Interpreter] Add Ignition statistics JavaScript extension.

This commit introduces IgnitionStatisticsExtension, which provides
methods for accessing Ignition statistics and counters from JavaScript.

The extension is registered when FLAG_ignition and
FLAG_trace_ignition_dispatches are both enabled.

For the moment, the only exposed function is
getIgnitionDispatchCounters(), which allows to retrieve Ignition
dispatch counters as a JavaScript object.

BUG=v8:4899
LOG=N

Review URL: https://codereview.chromium.org/1899133004

Cr-Commit-Position: refs/heads/master@{#35816}

BUILD.gn

@@ -1065,6 +1065,8 @@ source_set("v8_base") {
     "src/extensions/free-buffer-extension.h",
     "src/extensions/gc-extension.cc",
     "src/extensions/gc-extension.h",
+    "src/extensions/ignition-statistics-extension.cc",
+    "src/extensions/ignition-statistics-extension.h",
     "src/extensions/statistics-extension.cc",
     "src/extensions/statistics-extension.h",
     "src/extensions/trigger-failure-extension.cc",

src/assembler.cc

@@ -1075,7 +1075,7 @@ ExternalReference ExternalReference::interpreter_dispatch_table_address(
 ExternalReference ExternalReference::interpreter_dispatch_counters(
     Isolate* isolate) {
   return ExternalReference(
-      isolate->interpreter()->bytecode_dispatch_count_table());
+      isolate->interpreter()->bytecode_dispatch_counters_table());
 }
 
 ExternalReference::ExternalReference(StatsCounter* counter)

src/bootstrapper.cc

@@ -10,6 +10,7 @@
 #include "src/extensions/externalize-string-extension.h"
 #include "src/extensions/free-buffer-extension.h"
 #include "src/extensions/gc-extension.h"
+#include "src/extensions/ignition-statistics-extension.h"
 #include "src/extensions/statistics-extension.h"
 #include "src/extensions/trigger-failure-extension.h"
 #include "src/heap/heap.h"
@@ -73,7 +74,7 @@ v8::Extension* Bootstrapper::gc_extension_ = NULL;
 v8::Extension* Bootstrapper::externalize_string_extension_ = NULL;
 v8::Extension* Bootstrapper::statistics_extension_ = NULL;
 v8::Extension* Bootstrapper::trigger_failure_extension_ = NULL;
-
+v8::Extension* Bootstrapper::ignition_statistics_extension_ = NULL;
 
 void Bootstrapper::InitializeOncePerProcess() {
   free_buffer_extension_ = new FreeBufferExtension;
@@ -86,6 +87,8 @@ void Bootstrapper::InitializeOncePerProcess() {
   v8::RegisterExtension(statistics_extension_);
   trigger_failure_extension_ = new TriggerFailureExtension;
   v8::RegisterExtension(trigger_failure_extension_);
+  ignition_statistics_extension_ = new IgnitionStatisticsExtension;
+  v8::RegisterExtension(ignition_statistics_extension_);
 }
 
 
@@ -100,6 +103,8 @@ void Bootstrapper::TearDownExtensions() {
   statistics_extension_ = NULL;
   delete trigger_failure_extension_;
   trigger_failure_extension_ = NULL;
+  delete ignition_statistics_extension_;
+  ignition_statistics_extension_ = NULL;
 }
 
 
@@ -3219,6 +3224,9 @@ bool Genesis::InstallExtensions(Handle<Context> native_context,
           InstallExtension(isolate, "v8/statistics", &extension_states)) &&
          (!FLAG_expose_trigger_failure ||
           InstallExtension(isolate, "v8/trigger-failure", &extension_states)) &&
+         (!(FLAG_ignition && FLAG_trace_ignition_dispatches) ||
+          InstallExtension(isolate, "v8/ignition-statistics",
+                           &extension_states)) &&
          InstallRequestedExtensions(isolate, extensions, &extension_states);
 }
 

src/bootstrapper.h

@@ -136,6 +136,7 @@ class Bootstrapper final {
   static v8::Extension* externalize_string_extension_;
   static v8::Extension* statistics_extension_;
   static v8::Extension* trigger_failure_extension_;
+  static v8::Extension* ignition_statistics_extension_;
 
   DISALLOW_COPY_AND_ASSIGN(Bootstrapper);
 };

src/d8.cc

@@ -19,6 +19,7 @@
 
 #ifndef V8_SHARED
 #include <algorithm>
+#include <fstream>
 #include <vector>
 #endif  // !V8_SHARED
 
@@ -1276,6 +1277,21 @@ struct CounterAndKey {
 inline bool operator<(const CounterAndKey& lhs, const CounterAndKey& rhs) {
   return strcmp(lhs.key, rhs.key) < 0;
 }
+
+void Shell::WriteIgnitionDispatchCountersFile(v8::Isolate* isolate) {
+  HandleScope handle_scope(isolate);
+  Local<Context> context = Context::New(isolate);
+  Context::Scope context_scope(context);
+
+  Local<Object> dispatch_counters = reinterpret_cast<i::Isolate*>(isolate)
+                                        ->interpreter()
+                                        ->GetDispatchCountersObject();
+  std::ofstream dispatch_counters_stream(
+      i::FLAG_trace_ignition_dispatches_output_file);
+  dispatch_counters_stream << *String::Utf8Value(
+      JSON::Stringify(context, dispatch_counters).ToLocalChecked());
+}
+
 #endif  // !V8_SHARED
 
 
@@ -1314,12 +1330,6 @@ void Shell::OnExit(v8::Isolate* isolate) {
     delete [] counters;
   }
 
-  if (i::FLAG_trace_ignition_dispatches) {
-    reinterpret_cast<i::Isolate*>(isolate)
-        ->interpreter()
-        ->WriteDispatchCounters();
-  }
-
   delete counters_file_;
   delete counter_map_;
 #endif  // !V8_SHARED
@@ -2484,6 +2494,12 @@ int Shell::Main(int argc, char* argv[]) {
       RunShell(isolate);
     }
 
+#ifndef V8_SHARED
+    if (i::FLAG_ignition && i::FLAG_trace_ignition_dispatches) {
+      WriteIgnitionDispatchCountersFile(isolate);
+    }
+#endif
+
     // Shut down contexts and collect garbage.
     evaluation_context_.Reset();
 #ifndef V8_SHARED

src/d8.h

@@ -461,6 +461,7 @@ class Shell : public i::AllStatic {
   static i::List<Worker*> workers_;
   static i::List<SharedArrayBuffer::Contents> externalized_shared_contents_;
 
+  static void WriteIgnitionDispatchCountersFile(v8::Isolate* isolate);
   static Counter* GetCounter(const char* name, bool is_histogram);
   static Local<String> Stringify(Isolate* isolate, Local<Value> value);
 #endif  // !V8_SHARED

src/extensions/ignition-statistics-extension.cc

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/extensions/ignition-statistics-extension.h"
+
+#include "src/interpreter/bytecodes.h"
+#include "src/interpreter/interpreter.h"
+#include "src/isolate.h"
+
+namespace v8 {
+namespace internal {
+
+v8::Local<v8::FunctionTemplate>
+IgnitionStatisticsExtension::GetNativeFunctionTemplate(
+    v8::Isolate* isolate, v8::Local<v8::String> name) {
+  DCHECK_EQ(strcmp(*v8::String::Utf8Value(name), "getIgnitionDispatchCounters"),
+            0);
+  return v8::FunctionTemplate::New(
+      isolate, IgnitionStatisticsExtension::GetIgnitionDispatchCounters);
+}
+
+const char* const IgnitionStatisticsExtension::kSource =
+    "native function getIgnitionDispatchCounters();";
+
+void IgnitionStatisticsExtension::GetIgnitionDispatchCounters(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  DCHECK_EQ(args.Length(), 0);
+  DCHECK(FLAG_trace_ignition_dispatches);
+  args.GetReturnValue().Set(reinterpret_cast<Isolate*>(args.GetIsolate())
+                                ->interpreter()
+                                ->GetDispatchCountersObject());
+}
+
+}  // namespace internal
+}  // namespace v8

src/extensions/ignition-statistics-extension.h

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_EXTENSIONS_IGNITION_STATISTICS_EXTENSION_H_
+#define V8_EXTENSIONS_IGNITION_STATISTICS_EXTENSION_H_
+
+#include "include/v8.h"
+
+namespace v8 {
+namespace internal {
+
+class IgnitionStatisticsExtension : public v8::Extension {
+ public:
+  IgnitionStatisticsExtension()
+      : v8::Extension("v8/ignition-statistics", kSource) {}
+
+  v8::Local<v8::FunctionTemplate> GetNativeFunctionTemplate(
+      v8::Isolate* isolate, v8::Local<v8::String> name) override;
+
+  static void GetIgnitionDispatchCounters(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
+
+ private:
+  static const char* const kSource;
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_EXTENSIONS_IGNITION_STATISTICS_EXTENSION_H_

src/interpreter/interpreter.cc

@@ -38,9 +38,9 @@ void Interpreter::Initialize() {
 
   if (FLAG_trace_ignition_dispatches) {
     static const int kBytecodeCount = static_cast<int>(Bytecode::kLast) + 1;
-    bytecode_dispatch_count_table_.Reset(
+    bytecode_dispatch_counters_table_.Reset(
         new uintptr_t[kBytecodeCount * kBytecodeCount]);
-    memset(bytecode_dispatch_count_table_.get(), 0,
+    memset(bytecode_dispatch_counters_table_.get(), 0,
            sizeof(uintptr_t) * kBytecodeCount * kBytecodeCount);
   }
 
@@ -201,9 +201,18 @@ const char* Interpreter::LookupNameOfBytecodeHandler(Code* code) {
   return nullptr;
 }
 
-void Interpreter::WriteDispatchCounters() {
-  std::ofstream stream(FLAG_trace_ignition_dispatches_output_file);
-  static const int kBytecodeCount = static_cast<int>(Bytecode::kLast) + 1;
+uintptr_t Interpreter::GetDispatchCounter(Bytecode from, Bytecode to) const {
+  int from_index = Bytecodes::ToByte(from);
+  int to_index = Bytecodes::ToByte(to);
+  return bytecode_dispatch_counters_table_[from_index * kNumberOfBytecodes +
+                                           to_index];
+}
+
+Local<v8::Object> Interpreter::GetDispatchCountersObject() {
+  v8::Isolate* isolate = reinterpret_cast<v8::Isolate*>(isolate_);
+  Local<v8::Context> context = isolate->GetCurrentContext();
+
+  Local<v8::Object> counters_map = v8::Object::New(isolate);
 
   // Output is a JSON-encoded object of objects.
   //
@@ -216,35 +225,36 @@ void Interpreter::WriteDispatchCounters() {
   // object is always present, even if the value is empty because all counters
   // for that source are zero.
 
-  stream << '{';
-
-  for (int from_index = 0; from_index < kBytecodeCount; ++from_index) {
-    if (from_index > 0) stream << ",\n ";
-
+  for (int from_index = 0; from_index < kNumberOfBytecodes; ++from_index) {
     Bytecode from_bytecode = Bytecodes::FromByte(from_index);
-    stream << "\"" << Bytecodes::ToString(from_bytecode) << "\": {";
-
-    bool emitted_first = false;
-    for (int to_index = 0; to_index < kBytecodeCount; ++to_index) {
-      uintptr_t counter =
-          bytecode_dispatch_count_table_[from_index * kBytecodeCount +
-                                         to_index];
-      if (counter > 0) {
-        if (emitted_first) {
-          stream << ", ";
-        } else {
-          emitted_first = true;
-        }
+    Local<v8::Object> counters_row = v8::Object::New(isolate);
 
+    for (int to_index = 0; to_index < kNumberOfBytecodes; ++to_index) {
       Bytecode to_bytecode = Bytecodes::FromByte(to_index);
-        stream << '"' << Bytecodes::ToString(to_bytecode) << "\": " << counter;
+      uintptr_t counter = GetDispatchCounter(from_bytecode, to_bytecode);
+
+      if (counter > 0) {
+        std::string to_name = Bytecodes::ToString(to_bytecode);
+        Local<v8::String> to_name_object =
+            v8::String::NewFromUtf8(isolate, to_name.c_str(),
+                                    NewStringType::kNormal)
+                .ToLocalChecked();
+        Local<v8::Number> counter_object = v8::Number::New(isolate, counter);
+        CHECK(counters_row->Set(context, to_name_object, counter_object)
+                  .IsJust());
       }
     }
 
-    stream << "}";
+    std::string from_name = Bytecodes::ToString(from_bytecode);
+    Local<v8::String> from_name_object =
+        v8::String::NewFromUtf8(isolate, from_name.c_str(),
+                                NewStringType::kNormal)
+            .ToLocalChecked();
+
+    CHECK(counters_map->Set(context, from_name_object, counters_row).IsJust());
   }
 
-  stream << '}';
+  return counters_map;
 }
 
 // LdaZero

src/interpreter/interpreter.h

@@ -53,14 +53,14 @@ class Interpreter {
   void TraceCodegen(Handle<Code> code);
   const char* LookupNameOfBytecodeHandler(Code* code);
 
-  void WriteDispatchCounters();
+  Local<v8::Object> GetDispatchCountersObject();
 
   Address dispatch_table_address() {
     return reinterpret_cast<Address>(&dispatch_table_[0]);
   }
 
-  uintptr_t* bytecode_dispatch_count_table() {
-    return bytecode_dispatch_count_table_.get();
+  Address bytecode_dispatch_counters_table() {
+    return reinterpret_cast<Address>(bytecode_dispatch_counters_table_.get());
   }
 
  private:
@@ -143,6 +143,8 @@ class Interpreter {
   void DoStoreLookupSlot(LanguageMode language_mode,
                          InterpreterAssembler* assembler);
 
+  uintptr_t GetDispatchCounter(Bytecode from, Bytecode to) const;
+
   // Get dispatch table index of bytecode.
   static size_t GetDispatchTableIndex(Bytecode bytecode,
                                       OperandScale operand_scale);
@@ -151,10 +153,11 @@ class Interpreter {
 
   static const int kNumberOfWideVariants = 3;
   static const int kDispatchTableSize = kNumberOfWideVariants * (kMaxUInt8 + 1);
+  static const int kNumberOfBytecodes = static_cast<int>(Bytecode::kLast) + 1;
 
   Isolate* isolate_;
   Address dispatch_table_[kDispatchTableSize];
-  v8::base::SmartArrayPointer<uintptr_t> bytecode_dispatch_count_table_;
+  v8::base::SmartArrayPointer<uintptr_t> bytecode_dispatch_counters_table_;
 
   DISALLOW_COPY_AND_ASSIGN(Interpreter);
 };

src/v8.gyp

@@ -775,6 +775,8 @@
         'extensions/free-buffer-extension.h',
         'extensions/gc-extension.cc',
         'extensions/gc-extension.h',
+        'extensions/ignition-statistics-extension.cc',
+        'extensions/ignition-statistics-extension.h',
         'extensions/statistics-extension.cc',
         'extensions/statistics-extension.h',
         'extensions/trigger-failure-extension.cc',

test/mjsunit/ignition/ignition-statistics-extension.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --ignition --trace-ignition-dispatches
+
+assertEquals(typeof getIgnitionDispatchCounters, "function");
+
+var old_dispatch_counters = getIgnitionDispatchCounters();
+
+// Check that old_dispatch_counters is a non-empty object of objects, such that
+// the value of each property in the inner objects is a number.
+
+assertEquals(typeof old_dispatch_counters, "object");
+assertTrue(Object.getOwnPropertyNames(old_dispatch_counters).length > 0);
+for (var source_bytecode in old_dispatch_counters) {
+  var counters_row = old_dispatch_counters[source_bytecode];
+  assertEquals(typeof counters_row, "object");
+  for (var counter in counters_row) {
+    assertEquals(typeof counters_row[counter], "number");
+  }
+}
+
+// Do something
+function f(x) { return x*x; }
+f(42);
+
+var new_dispatch_counters = getIgnitionDispatchCounters();
+
+var old_source_bytecodes = Object.getOwnPropertyNames(old_dispatch_counters);
+var new_source_bytecodes = Object.getOwnPropertyNames(new_dispatch_counters);
+var common_source_bytecodes = new_source_bytecodes.filter(function (name) {
+  return old_source_bytecodes.indexOf(name) > -1;
+});
+
+// Check that the keys on the outer objects are the same
+assertEquals(common_source_bytecodes, old_source_bytecodes);
+assertEquals(common_source_bytecodes, new_source_bytecodes);
+
+common_source_bytecodes.forEach(function (source_bytecode) {
+  var new_counters_row = new_dispatch_counters[source_bytecode];
+  var old_counters_row = old_dispatch_counters[source_bytecode];
+
+  var old_destination_bytecodes = Object.getOwnPropertyNames(old_counters_row);
+  var new_destination_bytecodes = Object.getOwnPropertyNames(new_counters_row);
+
+  // Check that all the keys in old_ are in new_ too
+  old_destination_bytecodes.forEach(function (name) {
+    assertTrue(new_destination_bytecodes.indexOf(name) > -1);
+  });
+
+  // Check that for each source-destination pair, the counter has either
+  // appeared (was undefined before calling f()), is unchanged, or incremented.
+  new_destination_bytecodes.forEach(function (destination_bytecode) {
+    var new_counter = new_counters_row[destination_bytecode];
+    var old_counter = old_counters_row[destination_bytecode];
+    assertTrue(typeof new_counter === "number");
+    if (typeof old_counter === "number") {
+      assertTrue(new_counter >= old_counter);
+    }
+  });
+});