[Interpreter] Adds support to fetch return value on break at return.

src/debug/debug.cc

 // Copyright 2012 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/debug/debug.h"
 
 #include "src/api.h"
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
 #include "src/compilation-cache.h"
 #include "src/compiler.h"
 #include "src/deoptimizer.h"
 #include "src/execution.h"
 #include "src/frames-inl.h"
 #include "src/full-codegen/full-codegen.h"
 #include "src/global-handles.h"
-#include "src/interpreter/bytecodes.h"
 #include "src/interpreter/interpreter.h"
 #include "src/isolate-inl.h"
 #include "src/list.h"
 #include "src/log.h"
 #include "src/messages.h"
 #include "src/snapshot/natives.h"
 
 #include "include/v8-debug.h"
 
 namespace v8 {
@@ skipping 437 matching lines @@
 // Threading support.
 void Debug::ThreadInit() {
   thread_local_.break_count_ = 0;
   thread_local_.break_id_ = 0;
   thread_local_.break_frame_id_ = StackFrame::NO_ID;
   thread_local_.last_step_action_ = StepNone;
   thread_local_.last_statement_position_ = RelocInfo::kNoPosition;
   thread_local_.last_fp_ = 0;
   thread_local_.target_fp_ = 0;
   thread_local_.step_in_enabled_ = false;
+  thread_local_.return_value_ = Handle<Object>();
   // TODO(isolates): frames_are_dropped_?
   base::NoBarrier_Store(&thread_local_.current_debug_scope_,
                         static_cast<base::AtomicWord>(0));
 }
 
 
 char* Debug::ArchiveDebug(char* storage) {
   char* to = storage;
   MemCopy(to, reinterpret_cast<char*>(&thread_local_), sizeof(ThreadLocal));
   ThreadInit();
@@ skipping 66 matching lines @@
   ClearStepping();
 
   // Return debugger is not loaded.
   if (!is_loaded()) return;
 
   // Clear debugger context global handle.
   GlobalHandles::Destroy(Handle<Object>::cast(debug_context_).location());
   debug_context_ = Handle<Context>();
 }
 
-
-void Debug::Break(Arguments args, JavaScriptFrame* frame) {
+void Debug::Break(JavaScriptFrame* frame) {
   HandleScope scope(isolate_);
-  DCHECK(args.length() == 0);
 
   // Initialize LiveEdit.
   LiveEdit::InitializeThreadLocal(this);
 
   // Just continue if breaks are disabled or debugger cannot be loaded.
   if (break_disabled()) return;
 
   // Enter the debugger.
   DebugScope debug_scope(this);
   if (debug_scope.failed()) return;
@@ skipping 985 matching lines @@
       return;
     }
     // Move to next in list.
     prev = current;
     current = current->next();
   }
 
   UNREACHABLE();
 }
 
-Object* Debug::SetAfterBreakTarget(JavaScriptFrame* frame) {
-  if (frame->is_interpreted()) {
-    // Find the handler from the original bytecode array.
-    InterpretedFrame* interpreted_frame =
-        reinterpret_cast<InterpretedFrame*>(frame);
-    SharedFunctionInfo* shared = interpreted_frame->function()->shared();
-    BytecodeArray* bytecode_array = shared->bytecode_array();
-    int bytecode_offset = interpreted_frame->GetBytecodeOffset();
-    interpreter::Bytecode bytecode =
-        interpreter::Bytecodes::FromByte(bytecode_array->get(bytecode_offset));
-    return isolate_->interpreter()->GetBytecodeHandler(
-        bytecode, interpreter::OperandScale::kSingle);
-  } else {
-    after_break_target_ = NULL;
-    if (!LiveEdit::SetAfterBreakTarget(this)) {
-      // Continue just after the slot.
-      after_break_target_ = frame->pc();
-    }
-    return isolate_->heap()->undefined_value();
+void Debug::SetAfterBreakTarget(JavaScriptFrame* frame) {
+  after_break_target_ = NULL;
+  if (!LiveEdit::SetAfterBreakTarget(this)) {
+    // Continue just after the slot.
+    after_break_target_ = frame->pc();
   }
 }
 
 
 bool Debug::IsBreakAtReturn(JavaScriptFrame* frame) {
   HandleScope scope(isolate_);
 
   // Get the executing function in which the debug break occurred.
   Handle<JSFunction> function(JSFunction::cast(frame->function()));
   Handle<SharedFunctionInfo> shared(function->shared());
@@ skipping 720 matching lines @@
 DebugScope::DebugScope(Debug* debug)
     : debug_(debug),
       prev_(debug->debugger_entry()),
       save_(debug_->isolate_),
       no_termination_exceptons_(debug_->isolate_,
                                 StackGuard::TERMINATE_EXECUTION) {
   // Link recursive debugger entry.
   base::NoBarrier_Store(&debug_->thread_local_.current_debug_scope_,
                         reinterpret_cast<base::AtomicWord>(this));
 
-  // Store the previous break id and frame id.
+  // Store the previous break id, frame id and return value.
   break_id_ = debug_->break_id();
   break_frame_id_ = debug_->break_frame_id();
+  return_value_ = debug_->return_value();
 
   // Create the new break info. If there is no JavaScript frames there is no
   // break frame id.
   JavaScriptFrameIterator it(isolate());
   bool has_js_frames = !it.done();
   debug_->thread_local_.break_frame_id_ = has_js_frames ? it.frame()->id()
                                                         : StackFrame::NO_ID;
   debug_->SetNextBreakId();
 
   debug_->UpdateState();
@@ skipping 17 matching lines @@
     if (debug_->has_commands()) isolate()->stack_guard()->RequestDebugCommand();
   }
 
   // Leaving this debugger entry.
   base::NoBarrier_Store(&debug_->thread_local_.current_debug_scope_,
                         reinterpret_cast<base::AtomicWord>(prev_));
 
   // Restore to the previous break state.
   debug_->thread_local_.break_frame_id_ = break_frame_id_;
   debug_->thread_local_.break_id_ = break_id_;
+  debug_->thread_local_.return_value_ = return_value_;
 
   debug_->UpdateState();
 }
 
 
 MessageImpl MessageImpl::NewEvent(DebugEvent event,
                                   bool running,
                                   Handle<JSObject> exec_state,
                                   Handle<JSObject> event_data) {
   MessageImpl message(true, event, running,
@@ skipping 240 matching lines @@
 }
 
 
 void LockingCommandMessageQueue::Clear() {
   base::LockGuard<base::Mutex> lock_guard(&mutex_);
   queue_.Clear();
 }
 
 }  // namespace internal
 }  // namespace v8