Fix 'step in' after live edit stack manipulation

Review URL: http://codereview.chromium.org/3029033

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5150 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/debug-arm.cc

@@ -296,9 +296,10 @@ void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
 #undef __
 
 
-void Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
+Object** Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
                                        Handle<Code> code) {
   UNREACHABLE();
+  return NULL;
 }
 const int Debug::kFrameDropperFrameSize = -1;
 

src/debug-debugger.js

@@ -2115,6 +2115,10 @@ DebugCommandProcessor.prototype.changeLiveRequest_ = function(request, response)
   var result_description = Debug.LiveEdit.SetScriptSource(the_script,
       new_source, preview_only, change_log);
   response.body = {change_log: change_log, result: result_description};
+  
+  if (!preview_only && !this.running_ && result_description.stack_modified) {
+    response.body.stepin_recommended = true;
+  }
 };
 
 

src/debug.cc

@@ -1224,11 +1224,14 @@ void Debug::PrepareStep(StepAction step_action, int step_count) {
   it.FindBreakLocationFromAddress(frame->pc());
 
   // Compute whether or not the target is a call target.
-  bool is_call_target = false;
   bool is_load_or_store = false;
   bool is_inline_cache_stub = false;
+  bool is_at_restarted_function = false;
   Handle<Code> call_function_stub;
+
+  if (thread_local_.restarter_frame_function_pointer_ == NULL) {
     if (RelocInfo::IsCodeTarget(it.rinfo()->rmode())) {
+      bool is_call_target = false;
       Address target = it.rinfo()->target_address();
       Code* code = Code::GetCodeFromTargetAddress(target);
       if (code->is_call_stub() || code->is_keyed_call_stub()) {
@@ -1255,6 +1258,9 @@ void Debug::PrepareStep(StepAction step_action, int step_count) {
         call_function_stub = Handle<Code>(maybe_call_function_stub);
       }
     }
+  } else {
+    is_at_restarted_function = true;
+  }
 
   // If this is the last break code target step out is the only possibility.
   if (it.IsExit() || step_action == StepOut) {
@@ -1282,7 +1288,7 @@ void Debug::PrepareStep(StepAction step_action, int step_count) {
       ActivateStepOut(frames_it.frame());
     }
   } else if (!(is_inline_cache_stub || RelocInfo::IsConstructCall(it.rmode()) ||
-               !call_function_stub.is_null())
+               !call_function_stub.is_null() || is_at_restarted_function)
              || step_action == StepNext || step_action == StepMin) {
     // Step next or step min.
 
@@ -1294,9 +1300,18 @@ void Debug::PrepareStep(StepAction step_action, int step_count) {
         debug_info->code()->SourceStatementPosition(frame->pc());
     thread_local_.last_fp_ = frame->fp();
   } else {
+    // If there's restarter frame on top of the stack, just get the pointer
+    // to function which is going to be restarted.
+    if (is_at_restarted_function) {
+      Handle<JSFunction> restarted_function(
+          JSFunction::cast(*thread_local_.restarter_frame_function_pointer_));
+      Handle<SharedFunctionInfo> restarted_shared(
+          restarted_function->shared());
+      FloodWithOneShot(restarted_shared);
+    } else if (!call_function_stub.is_null()) {
       // If it's CallFunction stub ensure target function is compiled and flood
       // it with one shot breakpoints.
-    if (!call_function_stub.is_null()) {
+
       // Find out number of arguments from the stub minor key.
       // Reverse lookup required as the minor key cannot be retrieved
       // from the code object.
@@ -1767,9 +1782,12 @@ bool Debug::IsBreakAtReturn(JavaScriptFrame* frame) {
 
 
 void Debug::FramesHaveBeenDropped(StackFrame::Id new_break_frame_id,
-                                  FrameDropMode mode) {
+                                  FrameDropMode mode,
+                                  Object** restarter_frame_function_pointer) {
   thread_local_.frame_drop_mode_ = mode;
   thread_local_.break_frame_id_ = new_break_frame_id;
+  thread_local_.restarter_frame_function_pointer_ =
+      restarter_frame_function_pointer;
 }
 
 

src/debug.h

@@ -332,6 +332,7 @@ class Debug {
     k_after_break_target_address,
     k_debug_break_return_address,
     k_debug_break_slot_address,
+    k_restarter_frame_function_pointer,
     k_register_address
   };
 
@@ -339,6 +340,10 @@ class Debug {
   static Address* after_break_target_address() {
     return reinterpret_cast<Address*>(&thread_local_.after_break_target_);
   }
+  static Address* restarter_frame_function_pointer_address() {
+    Object*** address = &thread_local_.restarter_frame_function_pointer_;
+    return reinterpret_cast<Address*>(address);
+  }
 
   // Support for saving/restoring registers when handling debug break calls.
   static Object** register_address(int r) {
@@ -415,10 +420,22 @@ class Debug {
   };
 
   static void FramesHaveBeenDropped(StackFrame::Id new_break_frame_id,
-                                    FrameDropMode mode);
-
-  static void SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
+                                    FrameDropMode mode,
+                                    Object** restarter_frame_function_pointer);
+
+  // Initializes an artificial stack frame. The data it contains is used for:
+  //  a. successful work of frame dropper code which eventually gets control,
+  //  b. being compatible with regular stack structure for various stack
+  //     iterators.
+  // Returns address of stack allocated pointer to restarted function,
+  // the value that is called 'restarter_frame_function_pointer'. The value
+  // at this address (possibly updated by GC) may be used later when preparing
+  // 'step in' operation.
+  // The implementation is architecture-specific.
+  // TODO(LiveEdit): consider reviewing it as architecture-independent.
+  static Object** SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
                                          Handle<Code> code);
+
   static const int kFrameDropperFrameSize;
 
  private:
@@ -495,6 +512,11 @@ class Debug {
 
     // Pending interrupts scheduled while debugging.
     int pending_interrupts_;
+
+    // When restarter frame is on stack, stores the address
+    // of the pointer to function being restarted. Otherwise (most of the time)
+    // stores NULL. This pointer is used with 'step in' implementation.
+    Object** restarter_frame_function_pointer_;
   };
 
   // Storage location for registers when handling debug break calls
@@ -938,6 +960,10 @@ class Debug_Address {
     return Debug_Address(Debug::k_debug_break_return_address);
   }
 
+  static Debug_Address RestarterFrameFunctionPointer() {
+    return Debug_Address(Debug::k_restarter_frame_function_pointer);
+  }
+
   static Debug_Address Register(int reg) {
     return Debug_Address(Debug::k_register_address, reg);
   }
@@ -950,6 +976,9 @@ class Debug_Address {
         return reinterpret_cast<Address>(Debug::debug_break_return_address());
       case Debug::k_debug_break_slot_address:
         return reinterpret_cast<Address>(Debug::debug_break_slot_address());
+      case Debug::k_restarter_frame_function_pointer:
+        return reinterpret_cast<Address>(
+            Debug::restarter_frame_function_pointer_address());
       case Debug::k_register_address:
         return reinterpret_cast<Address>(Debug::register_address(reg_));
       default:

src/ia32/debug-ia32.cc

@@ -265,6 +265,10 @@ void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
 //   -- context
 //   -- frame base
 void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
+  ExternalReference restarter_frame_function_slot =
+      ExternalReference(Debug_Address::RestarterFrameFunctionPointer());
+  __ mov(Operand::StaticVariable(restarter_frame_function_slot), Immediate(0));
+
   // We do not know our frame height, but set esp based on ebp.
   __ lea(esp, Operand(ebp, -4 * kPointerSize));
 
@@ -288,7 +292,9 @@ void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
 #undef __
 
 
-void Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
+// TODO(LiveEdit): consider making it platform-independent.
+// TODO(LiveEdit): use more named constants instead of numbers.
+Object** Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
                                        Handle<Code> code) {
   ASSERT(bottom_js_frame->is_java_script());
 
@@ -298,7 +304,10 @@ void Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
 
   Memory::Object_at(fp - 3 * kPointerSize) = *code;
   Memory::Object_at(fp - 2 * kPointerSize) = Smi::FromInt(StackFrame::INTERNAL);
+
+  return reinterpret_cast<Object**>(&Memory::Object_at(fp - 4 * kPointerSize));
 }
+
 const int Debug::kFrameDropperFrameSize = 5;
 
 

src/liveedit.cc

@@ -1188,7 +1188,8 @@ static bool FixTryCatchHandler(StackFrame* top_frame,
 static const char* DropFrames(Vector<StackFrame*> frames,
                               int top_frame_index,
                               int bottom_js_frame_index,
-                              Debug::FrameDropMode* mode) {
+                              Debug::FrameDropMode* mode,
+                              Object*** restarter_frame_function_pointer) {
   if (Debug::kFrameDropperFrameSize < 0) {
     return "Stack manipulations are not supported in this architecture.";
   }
@@ -1238,8 +1239,11 @@ static const char* DropFrames(Vector<StackFrame*> frames,
   top_frame->set_pc(code->entry());
   pre_top_frame->SetCallerFp(bottom_js_frame->fp());
 
+  *restarter_frame_function_pointer =
       Debug::SetUpFrameDropperFrame(bottom_js_frame, code);
 
+  ASSERT((**restarter_frame_function_pointer)->IsJSFunction());
+
   for (Address a = unused_stack_top;
       a < unused_stack_bottom;
       a += kPointerSize) {
@@ -1328,8 +1332,10 @@ static const char* DropActivationsInActiveThread(
   }
 
   Debug::FrameDropMode drop_mode = Debug::FRAMES_UNTOUCHED;
+  Object** restarter_frame_function_pointer = NULL;
   const char* error_message = DropFrames(frames, top_frame_index,
-                                         bottom_js_frame_index, &drop_mode);
+                                         bottom_js_frame_index, &drop_mode,
+                                         &restarter_frame_function_pointer);
 
   if (error_message != NULL) {
     return error_message;
@@ -1343,7 +1349,8 @@ static const char* DropActivationsInActiveThread(
       break;
     }
   }
-  Debug::FramesHaveBeenDropped(new_id, drop_mode);
+  Debug::FramesHaveBeenDropped(new_id, drop_mode,
+                               restarter_frame_function_pointer);
 
   // Replace "blocked on active" with "replaced on active" status.
   for (int i = 0; i < array_len; i++) {

src/mips/debug-mips.cc

@@ -117,9 +117,10 @@ void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
 #undef __
 
 
-void Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
+Object** Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
                                        Handle<Code> code) {
   UNREACHABLE();
+  return NULL;
 }
 const int Debug::kFrameDropperFrameSize = -1;
 

src/x64/debug-x64.cc

@@ -213,9 +213,10 @@ void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
 #undef __
 
 
-void Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
+Object** Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
                                        Handle<Code> code) {
   UNREACHABLE();
+  return NULL;
 }
 const int Debug::kFrameDropperFrameSize = -1;