Reland of Type Feedback Vector lives in the closure

src/debug/liveedit.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/debug/liveedit.h"
 
 #include "src/ast/scopeinfo.h"
 #include "src/ast/scopes.h"
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 628 matching lines @@
 
 
 Handle<Code> FunctionInfoWrapper::GetFunctionCode() {
   Handle<Object> element = this->GetField(kCodeOffset_);
   Handle<JSValue> value_wrapper = Handle<JSValue>::cast(element);
   Handle<Object> raw_result = UnwrapJSValue(value_wrapper);
   CHECK(raw_result->IsCode());
   return Handle<Code>::cast(raw_result);
 }
 
-
-MaybeHandle<TypeFeedbackVector> FunctionInfoWrapper::GetFeedbackVector() {
+MaybeHandle<TypeFeedbackMetadata> FunctionInfoWrapper::GetFeedbackMetadata() {
   Handle<Object> element = this->GetField(kSharedFunctionInfoOffset_);
   if (element->IsJSValue()) {
     Handle<JSValue> value_wrapper = Handle<JSValue>::cast(element);
     Handle<Object> raw_result = UnwrapJSValue(value_wrapper);
     Handle<SharedFunctionInfo> shared =
         Handle<SharedFunctionInfo>::cast(raw_result);
-    return Handle<TypeFeedbackVector>(shared->feedback_vector(), isolate());
+    return Handle<TypeFeedbackMetadata>(shared->feedback_metadata(), isolate());
   } else {
     // Scripts may never have a SharedFunctionInfo created.
-    return MaybeHandle<TypeFeedbackVector>();
+    return MaybeHandle<TypeFeedbackMetadata>();
   }
 }
 
 
 Handle<Object> FunctionInfoWrapper::GetCodeScopeInfo() {
   Handle<Object> element = this->GetField(kCodeScopeInfoOffset_);
   return UnwrapJSValue(Handle<JSValue>::cast(element));
 }
 
 
@@ skipping 296 matching lines @@
 
 // Patch function literals.
 // Name 'literals' is a misnomer. Rather it's a cache for complex object
 // boilerplates and for a native context. We must clean cached values.
 // Additionally we may need to allocate a new array if number of literals
 // changed.
 class LiteralFixer {
  public:
   static void PatchLiterals(FunctionInfoWrapper* compile_info_wrapper,
                             Handle<SharedFunctionInfo> shared_info,
-                            Isolate* isolate) {
+                            bool feedback_metadata_changed, Isolate* isolate) {
     int new_literal_count = compile_info_wrapper->GetLiteralCount();
     int old_literal_count = shared_info->num_literals();
 
-    if (old_literal_count == new_literal_count) {
+    if (old_literal_count == new_literal_count && !feedback_metadata_changed) {
       // If literal count didn't change, simply go over all functions
       // and clear literal arrays.
       ClearValuesVisitor visitor;
       IterateJSFunctions(shared_info, &visitor);
     } else {
       // When literal count changes, we have to create new array instances.
       // Since we cannot create instances when iterating heap, we should first
       // collect all functions and fix their literal arrays.
       Handle<FixedArray> function_instances =
           CollectJSFunctions(shared_info, isolate);
-      Handle<TypeFeedbackVector> vector(shared_info->feedback_vector());
+      Handle<TypeFeedbackMetadata> feedback_metadata(
+          shared_info->feedback_metadata());
 
       for (int i = 0; i < function_instances->length(); i++) {
         Handle<JSFunction> fun(JSFunction::cast(function_instances->get(i)));
+        Handle<TypeFeedbackVector> vector =
+            TypeFeedbackVector::New(isolate, feedback_metadata);
         Handle<LiteralsArray> new_literals =
             LiteralsArray::New(isolate, vector, new_literal_count, TENURED);
         fun->set_literals(*new_literals);
       }
 
       shared_info->set_num_literals(new_literal_count);
     }
   }
 
  private:
@@ skipping 27 matching lines @@
     if (size > 0) {
       CollectVisitor collect_visitor(result);
       IterateJSFunctions(shared_info, &collect_visitor);
     }
     return result;
   }
 
   class ClearValuesVisitor {
    public:
     void visit(JSFunction* fun) {
-      FixedArray* literals = fun->literals();
-      int len = literals->length();
+      LiteralsArray* literals = fun->literals();
+      int len = literals->literals_count();
       for (int j = 0; j < len; j++) {
-        literals->set_undefined(j);
+        literals->set_literal_undefined(j);
       }
     }
   };
 
   class CountVisitor {
    public:
     void visit(JSFunction* fun) {
       count++;
     }
     int count;
@@ skipping 54 matching lines @@
 
 void LiveEdit::ReplaceFunctionCode(
     Handle<JSArray> new_compile_info_array,
     Handle<JSArray> shared_info_array) {
   Isolate* isolate = new_compile_info_array->GetIsolate();
 
   FunctionInfoWrapper compile_info_wrapper(new_compile_info_array);
   SharedInfoWrapper shared_info_wrapper(shared_info_array);
 
   Handle<SharedFunctionInfo> shared_info = shared_info_wrapper.GetInfo();
+  bool feedback_metadata_changed = false;
 
   if (shared_info->code()->kind() == Code::FUNCTION) {
     Handle<Code> code = compile_info_wrapper.GetFunctionCode();
     ReplaceCodeObject(Handle<Code>(shared_info->code()), code);
     Handle<Object> code_scope_info = compile_info_wrapper.GetCodeScopeInfo();
     if (code_scope_info->IsFixedArray()) {
       shared_info->set_scope_info(ScopeInfo::cast(*code_scope_info));
     }
     shared_info->DisableOptimization(kLiveEdit);
     // Update the type feedback vector, if needed.
-    MaybeHandle<TypeFeedbackVector> feedback_vector =
-        compile_info_wrapper.GetFeedbackVector();
-    if (!feedback_vector.is_null()) {
-      shared_info->set_feedback_vector(*feedback_vector.ToHandleChecked());
+    MaybeHandle<TypeFeedbackMetadata> feedback_metadata =
+        compile_info_wrapper.GetFeedbackMetadata();
+    if (!feedback_metadata.is_null()) {
+      Handle<TypeFeedbackMetadata> checked_feedback_metadata =
+          feedback_metadata.ToHandleChecked();
+      feedback_metadata_changed = checked_feedback_metadata->DiffersFrom(
+          shared_info->feedback_metadata());
+      shared_info->set_feedback_metadata(*checked_feedback_metadata);
     }
   }
 
   int start_position = compile_info_wrapper.GetStartPosition();
   int end_position = compile_info_wrapper.GetEndPosition();
   shared_info->set_start_position(start_position);
   shared_info->set_end_position(end_position);
 
-  LiteralFixer::PatchLiterals(&compile_info_wrapper, shared_info, isolate);
+  LiteralFixer::PatchLiterals(&compile_info_wrapper, shared_info,
+                              feedback_metadata_changed, isolate);
 
   DeoptimizeDependentFunctions(*shared_info);
   isolate->compilation_cache()->Remove(shared_info);
 }
 
 
 void LiveEdit::FunctionSourceUpdated(Handle<JSArray> shared_info_array) {
   SharedInfoWrapper shared_info_wrapper(shared_info_array);
   Handle<SharedFunctionInfo> shared_info = shared_info_wrapper.GetInfo();
 
@@ skipping 883 matching lines @@
   isolate_->active_function_info_listener()->FunctionCode(code);
 }
 
 
 bool LiveEditFunctionTracker::IsActive(Isolate* isolate) {
   return isolate->active_function_info_listener() != NULL;
 }
 
 }  // namespace internal
 }  // namespace v8