Support debugger inspection of locals in optimized frames

src/runtime.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 9920 matching lines @@
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
 
   // Count all frames which are relevant to debugging stack trace.
   int n = 0;
   StackFrame::Id id = isolate->debug()->break_frame_id();
   if (id == StackFrame::NO_ID) {
     // If there is no JavaScript stack frame count is 0.
     return Smi::FromInt(0);
   }
-  for (JavaScriptFrameIterator it(isolate, id); !it.done(); it.Advance()) n++;
+
+  for (JavaScriptFrameIterator it(isolate, id); !it.done(); it.Advance()) {
+    n += it.frame()->GetInlineCount();
+  }
   return Smi::FromInt(n);
 }
 
 
 static const int kFrameDetailsFrameIdIndex = 0;
 static const int kFrameDetailsReceiverIndex = 1;
 static const int kFrameDetailsFunctionIndex = 2;
 static const int kFrameDetailsArgumentCountIndex = 3;
 static const int kFrameDetailsLocalCountIndex = 4;
 static const int kFrameDetailsSourcePositionIndex = 5;
 static const int kFrameDetailsConstructCallIndex = 6;
 static const int kFrameDetailsAtReturnIndex = 7;
-static const int kFrameDetailsDebuggerFrameIndex = 8;
+static const int kFrameDetailsFlagsIndex = 8;
 static const int kFrameDetailsFirstDynamicIndex = 9;
 
 // Return an array with frame details
 // args[0]: number: break id
 // args[1]: number: frame index
 //
 // The array returned contains the following information:
 // 0: Frame id
 // 1: Receiver
 // 2: Function
 // 3: Argument count
 // 4: Local count
 // 5: Source position
 // 6: Constructor call
 // 7: Is at return
-// 8: Debugger frame
+// 8: Flags
 // Arguments name, value
 // Locals name, value
 // Return value if any
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetFrameDetails) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 2);
 
   // Check arguments.
   Object* check;
   { MaybeObject* maybe_check = Runtime_CheckExecutionState(
       RUNTIME_ARGUMENTS(isolate, args));
     if (!maybe_check->ToObject(&check)) return maybe_check;
   }
   CONVERT_NUMBER_CHECKED(int, index, Int32, args[1]);
   Heap* heap = isolate->heap();
 
   // Find the relevant frame with the requested index.
   StackFrame::Id id = isolate->debug()->break_frame_id();
   if (id == StackFrame::NO_ID) {
     // If there are no JavaScript stack frames return undefined.
     return heap->undefined_value();
   }
+
+  int deoptimized_frame_index = -1;  // Frame index in optimized frame.
+  DeoptimizedFrameInfo* deoptimized_frame = NULL;
+
   int count = 0;
   JavaScriptFrameIterator it(isolate, id);
   for (; !it.done(); it.Advance()) {
-    if (count == index) break;
-    count++;
+    if (index < count + it.frame()->GetInlineCount()) break;
+    count += it.frame()->GetInlineCount();
   }
   if (it.done()) return heap->undefined_value();
 
-  bool is_optimized_frame =
-      it.frame()->LookupCode()->kind() == Code::OPTIMIZED_FUNCTION;
+  if (it.frame()->is_optimized()) {
+    deoptimized_frame_index =
+        it.frame()->GetInlineCount() - (index - count) - 1;
+    deoptimized_frame = Deoptimizer::DebuggerInspectableFrame(
+        it.frame(),
+        deoptimized_frame_index,
+        isolate);
+  }
 
   // Traverse the saved contexts chain to find the active context for the
   // selected frame.
   SaveContext* save = isolate->save_context();
   while (save != NULL && !save->below(it.frame())) {
     save = save->prev();
   }
   ASSERT(save != NULL);
 
   // Get the frame id.
   Handle<Object> frame_id(WrapFrameId(it.frame()->id()), isolate);
 
   // Find source position.
   int position =
       it.frame()->LookupCode()->SourcePosition(it.frame()->pc());
 
   // Check for constructor frame.
   bool constructor = it.frame()->IsConstructor();
 
   // Get scope info and read from it for local variable information.
   Handle<JSFunction> function(JSFunction::cast(it.frame()->function()));
   Handle<SerializedScopeInfo> scope_info(function->shared()->scope_info());
+  ASSERT(*scope_info != SerializedScopeInfo::Empty());
   ScopeInfo<> info(*scope_info);
 
   // Get the locals names and values into a temporary array.
   //
   // TODO(1240907): Hide compiler-introduced stack variables
   // (e.g. .result)?  For users of the debugger, they will probably be
   // confusing.
   Handle<FixedArray> locals =
       isolate->factory()->NewFixedArray(info.NumberOfLocals() * 2);
 
   // Fill in the values of the locals.
-  if (is_optimized_frame) {
-    // If we are inspecting an optimized frame use undefined as the
-    // value for all locals.
-    //
-    // TODO(1140): We should be able to get the correct values
-    // for locals in optimized frames.
-    for (int i = 0; i < info.NumberOfLocals(); i++) {
-      locals->set(i * 2, *info.LocalName(i));
-      locals->set(i * 2 + 1, isolate->heap()->undefined_value());
-    }
-  } else {
-    int i = 0;
-    for (; i < info.number_of_stack_slots(); ++i) {
-      // Use the value from the stack.
-      locals->set(i * 2, *info.LocalName(i));
+  int i = 0;
+  for (; i < info.number_of_stack_slots(); ++i) {
+    // Use the value from the stack.
+    locals->set(i * 2, *info.LocalName(i));
+    if (it.frame()->is_optimized()) {
+      // Get the value from the deoptimized frame.
+      locals->set(i * 2 + 1,
+                  deoptimized_frame->GetExpression(i));
+    } else {
+      // Get the value from the stack.
       locals->set(i * 2 + 1, it.frame()->GetExpression(i));
     }
-    // Get the context containing declarations.
-    Handle<Context> context(
-        Context::cast(it.frame()->context())->declaration_context());
-    for (; i < info.NumberOfLocals(); ++i) {
-      Handle<String> name = info.LocalName(i);
-      locals->set(i * 2, *name);
-      locals->set(i * 2 + 1,
-                  context->get(scope_info->ContextSlotIndex(*name, NULL)));
-    }
+  }
+  // Get the context containing declarations.
+  Handle<Context> context(
+      Context::cast(it.frame()->context())->declaration_context());
+  for (; i < info.NumberOfLocals(); ++i) {
+    Handle<String> name = info.LocalName(i);
+    locals->set(i * 2, *name);
+    locals->set(i * 2 + 1,
+                context->get(scope_info->ContextSlotIndex(*name, NULL)));
   }
 
   // Check whether this frame is positioned at return. If not top
   // frame or if the frame is optimized it cannot be at a return.
   bool at_return = false;
-  if (!is_optimized_frame && index == 0) {
+  if (!it.frame()->is_optimized() && index == 0) {
     at_return = isolate->debug()->IsBreakAtReturn(it.frame());
   }
 
   // If positioned just before return find the value to be returned and add it
   // 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()) {
@@ skipping 60 matching lines @@
   } else {
     details->set(kFrameDetailsSourcePositionIndex, heap->undefined_value());
   }
 
   // Add the constructor information.
   details->set(kFrameDetailsConstructCallIndex, heap->ToBoolean(constructor));
 
   // Add the at return information.
   details->set(kFrameDetailsAtReturnIndex, heap->ToBoolean(at_return));
 
-  // Add information on whether this frame is invoked in the debugger context.
-  details->set(kFrameDetailsDebuggerFrameIndex,
-               heap->ToBoolean(*save->context() ==
-                   *isolate->debug()->debug_context()));
+  // Add flags to indicate information on whether this frame is
+  //   bit 0: invoked in the debugger context.
+  //   bit 1: optimized frame.
+  //   bit 2: inlined in optimized frame
+  int flags = 0;
+  if (*save->context() == *isolate->debug()->debug_context()) {
+    flags |= 1 << 0;
+  }
+  if (it.frame()->is_optimized()) {
+    flags |= 1 << 1;
+    if (deoptimized_frame_index > 0) {
+      flags |= 1 << 2;
+    }
+  }
+  details->set(kFrameDetailsFlagsIndex, Smi::FromInt(flags));
 
   // Fill the dynamic part.
   int details_index = kFrameDetailsFirstDynamicIndex;
 
   // Add arguments name and value.
   for (int i = 0; i < argument_count; i++) {
     // Name of the argument.
     if (i < info.number_of_parameters()) {
       details->set(details_index++, *info.parameter_name(i));
     } else {
       details->set(details_index++, heap->undefined_value());
     }
 
     // Parameter value. If we are inspecting an optimized frame, use
     // undefined as the value.
     //
     // TODO(3141533): We should be able to get the actual parameter
     // value for optimized frames.
-    if (!is_optimized_frame &&
+    if (!it.frame()->is_optimized() &&
         (i < it.frame()->ComputeParametersCount())) {
       details->set(details_index++, it.frame()->GetParameter(i));
     } else {
       details->set(details_index++, heap->undefined_value());
     }
   }
 
   // Add locals name and value from the temporary copy from the function frame.
   for (int i = 0; i < info.NumberOfLocals() * 2; i++) {
     details->set(details_index++, locals->get(i));
@@ skipping 15 matching lines @@
     // by creating correct wrapper object based on the calling frame's
     // global context.
     it.Advance();
     Handle<Context> calling_frames_global_context(
         Context::cast(Context::cast(it.frame()->context())->global_context()));
     receiver =
         isolate->factory()->ToObject(receiver, calling_frames_global_context);
   }
   details->set(kFrameDetailsReceiverIndex, *receiver);
 
+  // Get rid of the calculated deoptimized frame if any.
+  if (deoptimized_frame != NULL) {
+    Deoptimizer::DeleteDebuggerInspectableFrame(deoptimized_frame,
+                                                isolate);
+  }
+
   ASSERT_EQ(details_size, details_index);
   return *isolate->factory()->NewJSArrayWithElements(details);
 }
 
 
 // Copy all the context locals into an object used to materialize a scope.
 static bool CopyContextLocalsToScopeObject(
     Isolate* isolate,
     Handle<SerializedScopeInfo> serialized_scope_info,
     ScopeInfo<>& scope_info,
@@ skipping 2308 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal