[debug] Revert debug API removal

Debugging API is still in use by Node.

Revert "[debug] remove deprecated debug command message queue."
This reverts commit abdbfc95.

Revert "[debug] mark more unused debug API as deprecated."
This reverts commit d5ada19c.

BUG=v8:5530

Review-Url: https://codereview.chromium.org/2537313005
Cr-Commit-Position: refs/heads/master@{#41427}

include/v8-debug.h

@@ -16,9 +16,11 @@ namespace v8 {
 enum DebugEvent {
   Break = 1,
   Exception = 2,
-  AfterCompile = 3,
-  CompileError = 4,
-  AsyncTaskEvent = 5,
+  NewFunction = 3,
+  BeforeCompile = 4,
+  AfterCompile = 5,
+  CompileError = 6,
+  AsyncTaskEvent = 7,
 };
 
 class V8_EXPORT Debug {
@@ -142,7 +144,7 @@ class V8_EXPORT Debug {
    *
    * \param message the debug message handler message object
    *
-   * A MessageHandler does not take possession of the message data,
+   * A MessageHandler2 does not take possession of the message data,
    * and must not rely on the data persisting after the handler returns.
    */
   typedef void (*MessageHandler)(const Message& message);
@@ -164,8 +166,7 @@ class V8_EXPORT Debug {
   static void CancelDebugBreak(Isolate* isolate);
 
   // Check if a debugger break is scheduled in the given isolate.
-  V8_DEPRECATED("No longer supported",
-                static bool CheckDebugBreak(Isolate* isolate));
+  static bool CheckDebugBreak(Isolate* isolate);
 
   // Message based interface. The message protocol is JSON.
   V8_DEPRECATED("No longer supported",
@@ -203,9 +204,8 @@ class V8_EXPORT Debug {
   /**
    * Returns a mirror object for the given object.
    */
-  V8_DEPRECATED("No longer supported",
-                static MaybeLocal<Value> GetMirror(Local<Context> context,
-                                                   v8::Local<v8::Value> obj));
+  static MaybeLocal<Value> GetMirror(Local<Context> context,
+                                     v8::Local<v8::Value> obj);
 
   /**
    * Makes V8 process all pending debug messages.
@@ -254,9 +254,7 @@ class V8_EXPORT Debug {
    * While in the debug context, this method returns the top-most non-debug
    * context, if it exists.
    */
-  V8_DEPRECATED(
-      "No longer supported",
-      static MaybeLocal<Context> GetDebuggedContext(Isolate* isolate));
+  static MaybeLocal<Context> GetDebuggedContext(Isolate* isolate);
 
   /**
    * Enable/disable LiveEdit functionality for the given Isolate

src/api.cc

@@ -8734,7 +8734,9 @@ bool Debug::CheckDebugBreak(Isolate* isolate) {
 
 void Debug::SetMessageHandler(Isolate* isolate,
                               v8::Debug::MessageHandler handler) {
-  UNIMPLEMENTED();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  ENTER_V8(i_isolate);
+  i_isolate->debug()->SetMessageHandler(handler);
 }
 
 
@@ -8742,7 +8744,9 @@ void Debug::SendCommand(Isolate* isolate,
                         const uint16_t* command,
                         int length,
                         ClientData* client_data) {
-  UNIMPLEMENTED();
+  i::Isolate* internal_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  internal_isolate->debug()->EnqueueCommandMessage(
+      i::Vector<const uint16_t>(command, length), client_data);
 }
 
 
@@ -8767,11 +8771,28 @@ MaybeLocal<Value> Debug::Call(Local<Context> context,
 
 MaybeLocal<Value> Debug::GetMirror(Local<Context> context,
                                    v8::Local<v8::Value> obj) {
-  UNIMPLEMENTED();
-  return MaybeLocal<Value>();
+  PREPARE_FOR_EXECUTION(context, Debug, GetMirror, Value);
+  i::Debug* isolate_debug = isolate->debug();
+  has_pending_exception = !isolate_debug->Load();
+  RETURN_ON_FAILED_EXECUTION(Value);
+  i::Handle<i::JSObject> debug(isolate_debug->debug_context()->global_object());
+  auto name = isolate->factory()->NewStringFromStaticChars("MakeMirror");
+  auto fun_obj = i::JSReceiver::GetProperty(debug, name).ToHandleChecked();
+  auto v8_fun = Utils::CallableToLocal(i::Handle<i::JSFunction>::cast(fun_obj));
+  const int kArgc = 1;
+  v8::Local<v8::Value> argv[kArgc] = {obj};
+  Local<Value> result;
+  has_pending_exception =
+      !v8_fun->Call(context, Utils::ToLocal(debug), kArgc, argv)
+           .ToLocal(&result);
+  RETURN_ON_FAILED_EXECUTION(Value);
+  RETURN_ESCAPED(result);
+}
+
+void Debug::ProcessDebugMessages(Isolate* isolate) {
+  reinterpret_cast<i::Isolate*>(isolate)->debug()->ProcessDebugMessages(true);
 }
 
-void Debug::ProcessDebugMessages(Isolate* isolate) { UNIMPLEMENTED(); }
 
 Local<Context> Debug::GetDebugContext(Isolate* isolate) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
@@ -8781,8 +8802,12 @@ Local<Context> Debug::GetDebugContext(Isolate* isolate) {
 
 
 MaybeLocal<Context> Debug::GetDebuggedContext(Isolate* isolate) {
-  UNIMPLEMENTED();
-  return MaybeLocal<Context>();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  ENTER_V8(i_isolate);
+  if (!i_isolate->debug()->in_debug_scope()) return MaybeLocal<Context>();
+  i::Handle<i::Object> calling = i_isolate->GetCallingNativeContext();
+  if (calling.is_null()) return MaybeLocal<Context>();
+  return Utils::ToLocal(i::Handle<i::Context>::cast(calling));
 }
 
 void Debug::SetLiveEditEnabled(Isolate* isolate, bool enable) {

src/compiler.cc

@@ -962,6 +962,8 @@ Handle<SharedFunctionInfo> CompileToplevel(CompilationInfo* info) {
   FixedArray* array = isolate->native_context()->embedder_data();
   script->set_context_data(array->get(v8::Context::kDebugIdIndex));
 
+  isolate->debug()->OnBeforeCompile(script);
+
   Handle<SharedFunctionInfo> result;
 
   { VMState<COMPILER> state(info->isolate());

src/debug/debug.h

@@ -240,6 +240,47 @@ class DebugInfoListNode {
   DebugInfoListNode* next_;
 };
 
+// Message delivered to the message handler callback. This is either a debugger
+// event or the response to a command.
+class MessageImpl : public v8::Debug::Message {
+ public:
+  // Create a message object for a debug event.
+  static MessageImpl NewEvent(DebugEvent event, bool running,
+                              Handle<JSObject> exec_state,
+                              Handle<JSObject> event_data);
+
+  // Create a message object for the response to a debug command.
+  static MessageImpl NewResponse(DebugEvent event, bool running,
+                                 Handle<JSObject> exec_state,
+                                 Handle<JSObject> event_data,
+                                 Handle<String> response_json,
+                                 v8::Debug::ClientData* client_data);
+
+  // Implementation of interface v8::Debug::Message.
+  virtual bool IsEvent() const;
+  virtual bool IsResponse() const;
+  virtual DebugEvent GetEvent() const;
+  virtual bool WillStartRunning() const;
+  virtual v8::Local<v8::Object> GetExecutionState() const;
+  virtual v8::Local<v8::Object> GetEventData() const;
+  virtual v8::Local<v8::String> GetJSON() const;
+  virtual v8::Local<v8::Context> GetEventContext() const;
+  virtual v8::Debug::ClientData* GetClientData() const;
+  virtual v8::Isolate* GetIsolate() const;
+
+ private:
+  MessageImpl(bool is_event, DebugEvent event, bool running,
+              Handle<JSObject> exec_state, Handle<JSObject> event_data,
+              Handle<String> response_json, v8::Debug::ClientData* client_data);
+
+  bool is_event_;                 // Does this message represent a debug event?
+  DebugEvent event_;              // Debug event causing the break.
+  bool running_;                  // Will the VM start running after this event?
+  Handle<JSObject> exec_state_;   // Current execution state.
+  Handle<JSObject> event_data_;   // Data associated with the event.
+  Handle<String> response_json_;  // Response JSON if message holds a response.
+  v8::Debug::ClientData* client_data_;  // Client data passed with the request.
+};
 
 // Details of the debug event delivered to the debug event listener.
 class EventDetailsImpl : public v8::DebugInterface::EventDetails {
@@ -266,6 +307,67 @@ class EventDetailsImpl : public v8::DebugInterface::EventDetails {
   v8::Debug::ClientData* client_data_;  // Data passed to DebugBreakForCommand.
 };
 
+// Message send by user to v8 debugger or debugger output message.
+// In addition to command text it may contain a pointer to some user data
+// which are expected to be passed along with the command reponse to message
+// handler.
+class CommandMessage {
+ public:
+  static CommandMessage New(const Vector<uint16_t>& command,
+                            v8::Debug::ClientData* data);
+  CommandMessage();
+
+  // Deletes user data and disposes of the text.
+  void Dispose();
+  Vector<uint16_t> text() const { return text_; }
+  v8::Debug::ClientData* client_data() const { return client_data_; }
+
+ private:
+  CommandMessage(const Vector<uint16_t>& text, v8::Debug::ClientData* data);
+
+  Vector<uint16_t> text_;
+  v8::Debug::ClientData* client_data_;
+};
+
+// A Queue of CommandMessage objects.  A thread-safe version is
+// LockingCommandMessageQueue, based on this class.
+class CommandMessageQueue BASE_EMBEDDED {
+ public:
+  explicit CommandMessageQueue(int size);
+  ~CommandMessageQueue();
+  bool IsEmpty() const { return start_ == end_; }
+  CommandMessage Get();
+  void Put(const CommandMessage& message);
+  void Clear() { start_ = end_ = 0; }  // Queue is empty after Clear().
+
+ private:
+  // Doubles the size of the message queue, and copies the messages.
+  void Expand();
+
+  CommandMessage* messages_;
+  int start_;
+  int end_;
+  int size_;  // The size of the queue buffer.  Queue can hold size-1 messages.
+};
+
+// LockingCommandMessageQueue is a thread-safe circular buffer of CommandMessage
+// messages.  The message data is not managed by LockingCommandMessageQueue.
+// Pointers to the data are passed in and out. Implemented by adding a
+// Mutex to CommandMessageQueue.  Includes logging of all puts and gets.
+class LockingCommandMessageQueue BASE_EMBEDDED {
+ public:
+  LockingCommandMessageQueue(Logger* logger, int size);
+  bool IsEmpty() const;
+  CommandMessage Get();
+  void Put(const CommandMessage& message);
+  void Clear();
+
+ private:
+  Logger* logger_;
+  CommandMessageQueue queue_;
+  mutable base::Mutex mutex_;
+  DISALLOW_COPY_AND_ASSIGN(LockingCommandMessageQueue);
+};
 
 class DebugFeatureTracker {
  public:
@@ -299,11 +401,12 @@ class DebugFeatureTracker {
 class Debug {
  public:
   // Debug event triggers.
-  void OnDebugBreak(Handle<Object> break_points_hit);
+  void OnDebugBreak(Handle<Object> break_points_hit, bool auto_continue);
 
   void OnThrow(Handle<Object> exception);
   void OnPromiseReject(Handle<Object> promise, Handle<Object> value);
   void OnCompileError(Handle<Script> script);
+  void OnBeforeCompile(Handle<Script> script);
   void OnAfterCompile(Handle<Script> script);
   void OnAsyncTaskEvent(Handle<String> type, Handle<Object> id,
                         Handle<String> name);
@@ -311,11 +414,13 @@ class Debug {
   // API facing.
   void SetEventListener(Handle<Object> callback, Handle<Object> data);
   void SetMessageHandler(v8::Debug::MessageHandler handler);
+  void EnqueueCommandMessage(Vector<const uint16_t> command,
+                             v8::Debug::ClientData* client_data = NULL);
   MUST_USE_RESULT MaybeHandle<Object> Call(Handle<Object> fun,
                                            Handle<Object> data);
   Handle<Context> GetDebugContext();
   void HandleDebugBreak();
-  void ProcessDebugMessages();
+  void ProcessDebugMessages(bool debug_command_only);
 
   // Internal logic
   bool Load();
@@ -454,6 +559,7 @@ class Debug {
   }
 
   // Check whether there are commands in the command queue.
+  inline bool has_commands() const { return !command_queue_.IsEmpty(); }
   inline bool ignore_events() const { return is_suppressed_ || !is_active_; }
   inline bool break_disabled() const {
     return break_disabled_ || in_debug_event_listener_;
@@ -491,7 +597,11 @@ class Debug {
                          Handle<Object> event_data,
                          v8::Debug::ClientData* client_data);
   void ProcessCompileEvent(v8::DebugEvent event, Handle<Script> script);
-  void ProcessDebugEvent(v8::DebugEvent event, Handle<JSObject> event_data);
+  void ProcessDebugEvent(v8::DebugEvent event, Handle<JSObject> event_data,
+                         bool auto_continue);
+  void NotifyMessageHandler(v8::DebugEvent event, Handle<JSObject> exec_state,
+                            Handle<JSObject> event_data, bool auto_continue);
+  void InvokeMessageHandler(MessageImpl message);
 
   // Find the closest source position for a break point for a given position.
   int FindBreakablePosition(Handle<DebugInfo> debug_info, int source_position,
@@ -534,6 +644,10 @@ class Debug {
 
   v8::Debug::MessageHandler message_handler_;
 
+  static const int kQueueInitialSize = 4;
+  base::Semaphore command_received_;  // Signaled for each command received.
+  LockingCommandMessageQueue command_queue_;
+
   bool is_active_;
   bool is_suppressed_;
   bool live_edit_enabled_;

src/debug/debug.js

@@ -43,9 +43,11 @@ var sourceLineBeginningSkip = /^(?:\s*(?:\/\*.*?\*\/)*)*/;
 // from the API include file debug.h.
 Debug.DebugEvent = { Break: 1,
                      Exception: 2,
-                     AfterCompile: 3,
-                     CompileError: 4,
-                     AsyncTaskEvent: 5 };
+                     NewFunction: 3,
+                     BeforeCompile: 4,
+                     AfterCompile: 5,
+                     CompileError: 6,
+                     AsyncTaskEvent: 7 };
 
 // Types of exceptions that can be broken upon.
 Debug.ExceptionBreak = { Caught : 0,

src/execution.cc

@@ -451,7 +451,7 @@ Object* StackGuard::HandleInterrupts() {
     isolate_->heap()->HandleGCRequest();
   }
 
-  if (CheckDebugBreak()) {
+  if (CheckDebugBreak() || CheckDebugCommand()) {
     isolate_->debug()->HandleDebugBreak();
   }
 

src/execution.h

@@ -81,11 +81,12 @@ class StackGuard final {
 
 #define INTERRUPT_LIST(V)                       \
   V(DEBUGBREAK, DebugBreak, 0)                  \
-  V(TERMINATE_EXECUTION, TerminateExecution, 1) \
-  V(GC_REQUEST, GC, 2)                          \
-  V(INSTALL_CODE, InstallCode, 3)               \
-  V(API_INTERRUPT, ApiInterrupt, 4)             \
-  V(DEOPT_MARKED_ALLOCATION_SITES, DeoptMarkedAllocationSites, 5)
+  V(DEBUGCOMMAND, DebugCommand, 1)              \
+  V(TERMINATE_EXECUTION, TerminateExecution, 2) \
+  V(GC_REQUEST, GC, 3)                          \
+  V(INSTALL_CODE, InstallCode, 4)               \
+  V(API_INTERRUPT, ApiInterrupt, 5)             \
+  V(DEOPT_MARKED_ALLOCATION_SITES, DeoptMarkedAllocationSites, 6)
 
 #define V(NAME, Name, id)                                          \
   inline bool Check##Name() { return CheckInterrupt(NAME); }  \

src/inspector/v8-debugger.cc

@@ -559,7 +559,7 @@ void V8Debugger::handleV8DebugEvent(
   v8::DebugEvent event = eventDetails.GetEvent();
   if (event != v8::AsyncTaskEvent && event != v8::Break &&
       event != v8::Exception && event != v8::AfterCompile &&
-      event != v8::CompileError)
+      event != v8::BeforeCompile && event != v8::CompileError)
     return;
 
   v8::Local<v8::Context> eventContext = eventDetails.GetEventContext();

test/cctest/test-debug.cc

@@ -4125,6 +4125,7 @@ TEST(DebugBreak) {
 
   // Set the debug break flag.
   v8::Debug::DebugBreak(env->GetIsolate());
+  CHECK(v8::Debug::CheckDebugBreak(env->GetIsolate()));
 
   // Call all functions with different argument count.
   break_point_hit_count = 0;
@@ -4160,7 +4161,9 @@ TEST(DisableBreak) {
 
   // Set, test and cancel debug break.
   v8::Debug::DebugBreak(env->GetIsolate());
+  CHECK(v8::Debug::CheckDebugBreak(env->GetIsolate()));
   v8::Debug::CancelDebugBreak(env->GetIsolate());
+  CHECK(!v8::Debug::CheckDebugBreak(env->GetIsolate()));
 
   // Set the debug break flag.
   v8::Debug::DebugBreak(env->GetIsolate());
@@ -5259,7 +5262,7 @@ TEST(ContextData) {
   }
 
   // Two times compile event and two times break event.
-  CHECK_GT(event_listener_hit_count, 3);
+  CHECK_GT(event_listener_hit_count, 4);
 
   v8::Debug::SetDebugEventListener(isolate, nullptr);
   CheckDebuggerUnloaded(isolate);
@@ -5681,6 +5684,29 @@ TEST(NoDebugBreakInAfterCompileEventListener) {
   CheckDebuggerUnloaded(env->GetIsolate());
 }
 
+TEST(GetMirror) {
+  DebugLocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+  v8::HandleScope scope(isolate);
+  v8::Local<v8::Context> context = env.context();
+  v8::Local<v8::Value> obj =
+      v8::Debug::GetMirror(context, v8_str(isolate, "hodja")).ToLocalChecked();
+  v8::ScriptCompiler::Source source(
+      v8_str("function runTest(mirror) {"
+             "  return mirror.isString() && (mirror.length() == 5);"
+             "}"
+             ""
+             "runTest;"));
+  v8::Local<v8::Function> run_test = v8::Local<v8::Function>::Cast(
+      v8::ScriptCompiler::CompileUnboundScript(isolate, &source)
+          .ToLocalChecked()
+          ->BindToCurrentContext()
+          ->Run(context)
+          .ToLocalChecked());
+  v8::Local<v8::Value> result =
+      run_test->Call(context, env->Global(), 1, &obj).ToLocalChecked();
+  CHECK(result->IsTrue());
+}
 
 // Test that the debug break flag works with function.apply.
 TEST(DebugBreakFunctionApply) {
@@ -5820,6 +5846,41 @@ TEST(NoDebugContextWhenDebuggerDisabled) {
   CHECK(context.IsEmpty());
 }
 
+static void DebugEventCheckContext(
+    const v8::Debug::EventDetails& event_details) {
+  if (event_details.GetEvent() == v8::Break) {
+    v8::Isolate* isolate = event_details.GetIsolate();
+    CHECK(v8::Debug::GetDebuggedContext(isolate)
+              .ToLocalChecked()
+              ->Global()
+              ->Equals(isolate->GetCurrentContext(),
+                       event_details.GetEventContext()->Global())
+              .FromJust());
+  }
+}
+
+static void CheckContext(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  CHECK(v8::Debug::GetDebuggedContext(args.GetIsolate()).IsEmpty());
+}
+
+TEST(DebuggedContext) {
+  DebugLocalContext env;
+  v8::Isolate* isolate = env->GetIsolate();
+
+  v8::Debug::SetDebugEventListener(isolate, DebugEventCheckContext);
+
+  v8::Local<v8::Function> foo =
+      CompileFunction(&env, "function foo(){bar=0;}", "foo");
+
+  SetBreakPoint(foo, 0);
+  foo->Call(env.context(), env->Global(), 0, nullptr).ToLocalChecked();
+
+  v8::Local<v8::Function> fun = v8::FunctionTemplate::New(isolate, CheckContext)
+                                    ->GetFunction(env.context())
+                                    .ToLocalChecked();
+  fun->Call(env.context(), env->Global(), 0, nullptr).ToLocalChecked();
+}
+
 static v8::Local<v8::Value> expected_callback_data;
 static void DebugEventContextChecker(const v8::Debug::EventDetails& details) {
   CHECK(details.GetEventContext() == expected_context);

test/debugger/test-api.js

@@ -30,8 +30,11 @@ class DebugWrapper {
     // Debug events which can occur in the V8 JavaScript engine.
     this.DebugEvent = { Break: 1,
                         Exception: 2,
-                        AfterCompile: 3,
-                        CompileError: 4,
+                        NewFunction: 3,
+                        BeforeCompile: 4,
+                        AfterCompile: 5,
+                        CompileError: 6,
+                        AsyncTaskEvent: 7
                       };
 
     // The different types of steps.