Working Local Scope in v8

patch.diff

diff --git a/src/runtime.cc b/src/runtime.cc
index 1616434..a72eff3 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -14552,6 +14552,59 @@ RUNTIME_FUNCTION(Runtime_GetScript) {
 }
 
 
+// Get variabels in this function scope
+RUNTIME_FUNCTION(Runtime_LocalVariabels) {
+  HandleScope scope(isolate);
+
+  DCHECK(args.length() == 2);
+
+  CONVERT_ARG_HANDLE_CHECKED(JSObject, locals, 0);
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 1);
+
+  // Unpack the function scope
+  SharedFunctionInfo* shared = function->shared();
+  ScopeInfo* scope_info = shared->scope_info();
+  Object* script_obj = shared->script();
+
+  if (script_obj->IsScript()) {
+    // Search the frames for a function match
+    JavaScriptFrame* frame;
+    bool found = false;
+
+    for (JavaScriptFrameIterator it(isolate); !it.done(); it.Advance()) {
+      frame = it.frame();
+      if (frame->function() == *function.location()) {
+        found = true;
+        break;
+      }
+    }
+
+    // function is not in active scope, stop here
+    if (!found) {
+      return isolate->heap()->undefined_value();
+    }
+
+    // Build an object containing the local variables
+    int stack_local_count = scope_info->StackLocalCount();
+
+    for (int i = 0; i < stack_local_count; i++) {
+      String* name = scope_info->StackLocalName(i);
+      Object* value = frame->GetExpression(i);
+
+      Handle<String> prop_name = Handle<String>(name, isolate);
+      Handle<Object> prop_value = Handle<Object>(value, isolate);
+      JSObject::SetProperty(locals, prop_name, prop_value, SLOPPY).Assert();
+    }
+    return isolate->heap()->undefined_value();
+  }
+
+  return isolate->heap()->undefined_value();
+}
+
+
 // Collect the raw data for a stack trace.  Returns an array of 4
 // element segments each containing a receiver, function, code and
 // native code offset.
diff --git a/src/runtime.h b/src/runtime.h
index ef42b52..c22146a 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -207,6 +207,7 @@ namespace internal {
   F(FunctionIsAPIFunction, 1, 1)                                      \
   F(FunctionIsBuiltin, 1, 1)                                          \
   F(GetScript, 1, 1)                                                  \
+  F(LocalVariabels, 2, 1)                                             \
   F(CollectStackTrace, 2, 1)                                          \
   F(GetV8Version, 0, 1)                                               \
                                                                       \

run.sh

d8 --allow-natives-syntax test.js

{
	"a": true,
	"b": {
		"prop": "you"
	},
	"c": "Bad Ass",
	"d": [
		"my",
		"life",
		0
	]
}

test.js

function GetLocals(func) {
    var locals = {};
    %LocalVariabels(locals, func);
    return locals;
}

function foo() {
    var a = true;
    var b = { "prop": "you" };
    var c = "Bad Ass";
    var d = ["my", "life", 0];

    print(JSON.stringify(GetLocals(foo), null, '\t'));
}

foo();