[deoptimizer] Report if speculation bit changed with --trace-deopt

This CL adds output related to the no speculation bit on the feedback
vector. Messages appear on two occasions:
  - if a feedback vector is read from the deoptimization entry
  - if the no-speculation bit on a feedback vector is set
The latter only happens during object materialization.

Bug: v8:7127
Change-Id: I9676323d3223441472539a544d3309687dba27a3
Reviewed-on: https://chromium-review.googlesource.com/849092Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50496}

src/deoptimizer.cc

@@ -605,7 +605,8 @@ void Deoptimizer::DoComputeOutputFrames() {
            input_data->OptimizationId()->value(), bailout_id_, fp_to_sp_delta_,
            caller_frame_top_);
     if (bailout_type_ == EAGER || bailout_type_ == SOFT) {
-      compiled_code_->PrintDeoptLocation(trace_scope_->file(), from_);
+      compiled_code_->PrintDeoptLocation(
+          trace_scope_->file(), "            ;;; deoptimize at ", from_);
     }
   }
 
@@ -1715,7 +1716,12 @@ void Deoptimizer::MaterializeHeapObjects() {
 
   translated_state_.VerifyMaterializedObjects();
 
-  translated_state_.DoUpdateFeedback();
+  bool feedback_updated = translated_state_.DoUpdateFeedback();
+  if (trace_scope_ != nullptr && feedback_updated) {
+    PrintF(trace_scope_->file(), "Feedback updated");
+    compiled_code_->PrintDeoptLocation(trace_scope_->file(),
+                                       " from deoptimization at ", from_);
+  }
 
   isolate_->materialized_object_store()->Remove(
       reinterpret_cast<Address>(stack_fp_));
@@ -3229,7 +3235,7 @@ void TranslatedState::Init(Address input_frame_pointer,
   CHECK_LE(update_feedback_count, 1);
 
   if (update_feedback_count == 1) {
-    ReadUpdateFeedback(iterator, literal_array);
+    ReadUpdateFeedback(iterator, literal_array, trace_file);
   }
 
   std::stack<int> nested_counts;
@@ -3896,20 +3902,27 @@ void TranslatedState::VerifyMaterializedObjects() {
 #endif
 }
 
-void TranslatedState::DoUpdateFeedback() {
+bool TranslatedState::DoUpdateFeedback() {
   if (!feedback_vector_handle_.is_null()) {
     CHECK(!feedback_slot_.IsInvalid());
     isolate()->CountUsage(v8::Isolate::kDeoptimizerDisableSpeculation);
     CallICNexus nexus(feedback_vector_handle_, feedback_slot_);
     nexus.SetSpeculationMode(SpeculationMode::kDisallowSpeculation);
+    return true;
   }
+  return false;
 }
 
 void TranslatedState::ReadUpdateFeedback(TranslationIterator* iterator,
-                                         FixedArray* literal_array) {
+                                         FixedArray* literal_array,
+                                         FILE* trace_file) {
   CHECK_EQ(Translation::UPDATE_FEEDBACK, iterator->Next());
   feedback_vector_ = FeedbackVector::cast(literal_array->get(iterator->Next()));
   feedback_slot_ = FeedbackSlot(iterator->Next());
+  if (trace_file != nullptr) {
+    PrintF(trace_file, "  reading FeedbackVector (slot %d)\n",
+           feedback_slot_.ToInt());
+  }
 }
 
 }  // namespace internal

src/deoptimizer.h

@@ -297,7 +297,7 @@ class TranslatedState {
             FILE* trace_file, int parameter_count);
 
   void VerifyMaterializedObjects();
-  void DoUpdateFeedback();
+  bool DoUpdateFeedback();
 
  private:
   friend TranslatedValue;
@@ -345,7 +345,7 @@ class TranslatedState {
       Handle<Map> map, const DisallowHeapAllocation& no_allocation);
 
   void ReadUpdateFeedback(TranslationIterator* iterator,
-                          FixedArray* literal_array);
+                          FixedArray* literal_array, FILE* trace_file);
 
   TranslatedValue* ResolveCapturedObject(TranslatedValue* slot);
   TranslatedValue* GetValueByObjectIndex(int object_index);

src/objects.cc

@@ -14142,11 +14142,11 @@ void JSFunction::ClearTypeFeedbackInfo() {
   }
 }
 
-void Code::PrintDeoptLocation(FILE* out, Address pc) {
+void Code::PrintDeoptLocation(FILE* out, const char* str, Address pc) {
   Deoptimizer::DeoptInfo info = Deoptimizer::GetDeoptInfo(this, pc);
   class SourcePosition pos = info.position;
   if (info.deopt_reason != DeoptimizeReason::kUnknown || pos.IsKnown()) {
-    PrintF(out, "            ;;; deoptimize at ");
+    PrintF(out, "%s", str);
     OFStream outstr(out);
     pos.Print(outstr, this);
     PrintF(out, ", %s\n", DeoptimizeReasonToString(info.deopt_reason));

src/objects/code.h

@@ -389,7 +389,7 @@ class Code : public HeapObject {
   DECL_PRINTER(Code)
   DECL_VERIFIER(Code)
 
-  void PrintDeoptLocation(FILE* out, Address pc);
+  void PrintDeoptLocation(FILE* out, const char* str, Address pc);
   bool CanDeoptAt(Address pc);
 
   inline HandlerTable::CatchPrediction GetBuiltinCatchPrediction();