From 26aaa3b005824396987101fec717f37970cb51ab Mon Sep 17 00:00:00 2001
From: "pfeldman@chromium.org"
 <pfeldman@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Thu, 15 Mar 2012 14:17:22 +0000
Subject: [PATCH] Debugger: naive implementation of "step into
 Function.prototype.bind".

Review URL: https://chromiumcodereview.appspot.com/9705018

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11058 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/debug.cc                               | 25 +++++++++++++++++++++----
 src/debug.h                                |  1 +
 test/mjsunit/debug-stepin-function-call.js | 17 ++++++++++++++++-
 3 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/src/debug.cc b/src/debug.cc
index 2058d48..01f6f39 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -1223,6 +1223,18 @@ void Debug::FloodWithOneShot(Handle<SharedFunctionInfo> shared) {
 }
 
 
+void Debug::FloodBoundFunctionWithOneShot(Handle<JSFunction> function) {
+  Handle<FixedArray> new_bindings(function->function_bindings());
+  Handle<Object> bindee(new_bindings->get(JSFunction::kBoundFunctionIndex));
+
+  if (!bindee.is_null() && bindee->IsJSFunction() &&
+      !JSFunction::cast(*bindee)->IsBuiltin()) {
+    Handle<SharedFunctionInfo> shared_info(JSFunction::cast(*bindee)->shared());
+    Debug::FloodWithOneShot(shared_info);
+  }
+}
+
+
 void Debug::FloodHandlerWithOneShot() {
   // Iterate through the JavaScript stack looking for handlers.
   StackFrame::Id id = break_frame_id();
@@ -1442,8 +1454,10 @@ void Debug::PrepareStep(StepAction step_action, int step_count) {
           expressions_count - 2 - call_function_arg_count);
       if (fun->IsJSFunction()) {
         Handle<JSFunction> js_function(JSFunction::cast(fun));
-        // Don't step into builtins.
-        if (!js_function->IsBuiltin()) {
+        if (js_function->shared()->bound()) {
+          Debug::FloodBoundFunctionWithOneShot(js_function);
+        } else if (!js_function->IsBuiltin()) {
+          // Don't step into builtins.
           // It will also compile target function if it's not compiled yet.
           FloodWithOneShot(Handle<SharedFunctionInfo>(js_function->shared()));
         }
@@ -1639,8 +1653,11 @@ void Debug::HandleStepIn(Handle<JSFunction> function,
   // Flood the function with one-shot break points if it is called from where
   // step into was requested.
   if (fp == step_in_fp()) {
-    // Don't allow step into functions in the native context.
-    if (!function->IsBuiltin()) {
+    if (function->shared()->bound()) {
+      // Handle Function.prototype.bind
+      Debug::FloodBoundFunctionWithOneShot(function);
+    } else if (!function->IsBuiltin()) {
+      // Don't allow step into functions in the native context.
       if (function->shared()->code() ==
           Isolate::Current()->builtins()->builtin(Builtins::kFunctionApply) ||
           function->shared()->code() ==
diff --git a/src/debug.h b/src/debug.h
index b9384e5..474b90b 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -239,6 +239,7 @@ class Debug {
   void ClearBreakPoint(Handle<Object> break_point_object);
   void ClearAllBreakPoints();
   void FloodWithOneShot(Handle<SharedFunctionInfo> shared);
+  void FloodBoundFunctionWithOneShot(Handle<JSFunction> function);
   void FloodHandlerWithOneShot();
   void ChangeBreakOnException(ExceptionBreakType type, bool enable);
   bool IsBreakOnException(ExceptionBreakType type);
diff --git a/test/mjsunit/debug-stepin-function-call.js b/test/mjsunit/debug-stepin-function-call.js
index 385fcb2..3b5240c 100644
--- a/test/mjsunit/debug-stepin-function-call.js
+++ b/test/mjsunit/debug-stepin-function-call.js
@@ -135,8 +135,15 @@ function apply4() {
   var yetAnotherLocal = 10;
 }
 
+// Test step into bound function.
+function bind1() {
+  var bound = g.bind(null, 3);
+  debugger;
+  bound();
+}
+
 var testFunctions =
-    [call1, call2, call3, call4, apply1, apply2, apply3, apply4];
+    [call1, call2, call3, call4, apply1, apply2, apply3, apply4, bind1];
 
 for (var i = 0; i < testFunctions.length; i++) {
   state = 0;
@@ -145,5 +152,13 @@ for (var i = 0; i < testFunctions.length; i++) {
   assertEquals(3, state);
 }
 
+// Test global bound function.
+state = 0;
+var globalBound = g.bind(null, 3);
+debugger;
+globalBound();
+assertNull(exception);
+assertEquals(3, state);
+
 // Get rid of the debug event listener.
 Debug.setListener(null);
\ No newline at end of file
-- 
2.7.4