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

src/runtime/runtime-debug.cc

Index: src/runtime/runtime-debug.cc
diff --git a/src/runtime/runtime-debug.cc b/src/runtime/runtime-debug.cc
index 631f5e8153e82538bfc19c170749b78ce836f504..e1d9b7a611123a2188baad8e2ca6a0cb195385ef 100644
--- a/src/runtime/runtime-debug.cc
+++ b/src/runtime/runtime-debug.cc
@@ -5,11 +5,13 @@
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
-#include "src/debug/debug.h"
 #include "src/debug/debug-evaluate.h"
 #include "src/debug/debug-frames.h"
 #include "src/debug/debug-scopes.h"
+#include "src/debug/debug.h"
 #include "src/frames-inl.h"
+#include "src/interpreter/bytecodes.h"
+#include "src/interpreter/interpreter.h"
 #include "src/isolate-inl.h"
 #include "src/runtime/runtime.h"
 
@@ -18,11 +20,39 @@ namespace internal {
 
 RUNTIME_FUNCTION(Runtime_DebugBreak) {
   SealHandleScope shs(isolate);
-  DCHECK(args.length() == 0);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, value, 0);
+  isolate->debug()->set_return_value(value);
+
   // Get the top-most JavaScript frame.
   JavaScriptFrameIterator it(isolate);
   isolate->debug()->Break(args, it.frame());
-  return isolate->debug()->SetAfterBreakTarget(it.frame());
+
+  isolate->debug()->SetAfterBreakTarget(it.frame());
+  return *isolate->debug()->get_return_value();
+}
+
+RUNTIME_FUNCTION(Runtime_DebugBreakOnBytecode) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, value, 0);
+  isolate->debug()->set_return_value(value);
+
+  // Get the top-most JavaScript frame.
+  JavaScriptFrameIterator it(isolate);
+  isolate->debug()->Break(args, it.frame());

[Yang, 2016/03/23 14:22:30]

let's not pass args to Debug::Break anymore. It's not used there. Probably some
historic artifact :)

[mythria, 2016/03/23 15:29:12]

Done.

+
+  // Return the handler from the original bytecode array.
+  DCHECK(it.frame()->is_interpreted());
+  InterpretedFrame* interpreted_frame =
+      reinterpret_cast<InterpretedFrame*>(it.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);
 }
 
 
@@ -591,31 +621,7 @@ RUNTIME_FUNCTION(Runtime_GetFrameDetails) {
   // to the frame information.
   Handle<Object> return_value = isolate->factory()->undefined_value();
   if (at_return) {
-    StackFrameIterator it2(isolate);
-    Address internal_frame_sp = NULL;
-    while (!it2.done()) {
-      if (it2.frame()->is_internal()) {
-        internal_frame_sp = it2.frame()->sp();
-      } else {
-        if (it2.frame()->is_java_script()) {
-          if (it2.frame()->id() == it.frame()->id()) {
-            // The internal frame just before the JavaScript frame contains the
-            // value to return on top. A debug break at return will create an
-            // internal frame to store the return value (eax/rax/r0) before
-            // entering the debug break exit frame.
-            if (internal_frame_sp != NULL) {
-              return_value =
-                  Handle<Object>(Memory::Object_at(internal_frame_sp), isolate);
-              break;
-            }
-          }
-        }
-
-        // Indicate that the previous frame was not an internal frame.
-        internal_frame_sp = NULL;
-      }
-      it2.Advance();
-    }
+    return_value = isolate->debug()->get_return_value();
   }
 
   // Now advance to the arguments adapter frame (if any). It contains all