Type Feedback Vector lives in the closure

src/objects.h

 // Copyright 2015 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.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 836 matching lines @@
 class LiteralsArray;
 class LookupIterator;
 class ObjectHashTable;
 class ObjectVisitor;
 class PropertyCell;
 class PropertyDescriptor;
 class SafepointEntry;
 class SharedFunctionInfo;
 class StringStream;
 class TypeFeedbackInfo;
+class TypeFeedbackMetadata;
 class TypeFeedbackVector;
 class WeakCell;
 class TransitionArray;
 
 // We cannot just say "class HeapType;" if it is created from a template... =8-?
 template<class> class TypeImpl;
 struct HeapTypeConfig;
 typedef TypeImpl<HeapTypeConfig> HeapType;
 
 
@@ skipping 3779 matching lines @@
 #endif
 };
 
 
 // A literals array contains the literals for a JSFunction. It also holds
 // the type feedback vector.
 class LiteralsArray : public FixedArray {
  public:
   static const int kVectorIndex = 0;
   static const int kFirstLiteralIndex = 1;
-  static const int kOffsetToFirstLiteral =
-      FixedArray::kHeaderSize + kPointerSize;
+  static const int kFeedbackVectorOffset = FixedArray::kHeaderSize;
+  static const int kOffsetToFirstLiteral = kFeedbackVectorOffset + kPointerSize;
 
   static int OffsetOfLiteralAt(int index) {
     return SizeFor(index + kFirstLiteralIndex);
   }
 
   inline TypeFeedbackVector* feedback_vector() const;
   inline void set_feedback_vector(TypeFeedbackVector* vector);
   inline Object* literal(int literal_index) const;
   inline void set_literal(int literal_index, Object* literal);
+  inline void set_literal_undefined(int literal_index);
   inline int literals_count() const;
 
   static Handle<LiteralsArray> New(Isolate* isolate,
                                    Handle<TypeFeedbackVector> vector,
                                    int number_of_literals,
                                    PretenureFlag pretenure);
 
   DECLARE_CAST(LiteralsArray)
 
  private:
@@ skipping 1801 matching lines @@
   // Returns entry from optimized code map for specified context and OSR entry.
   // Note that {code == nullptr, literals == nullptr} indicates no matching
   // entry has been found, whereas {code, literals == nullptr} indicates that
   // code is context-independent.
   CodeAndLiterals SearchOptimizedCodeMap(Context* native_context,
                                          BailoutId osr_ast_id);
 
   // Clear optimized code map.
   void ClearOptimizedCodeMap();
 
+  // Like ClearOptimizedCodeMap, but preserves literals.
+  void ClearCodeFromOptimizedCodeMap();
+
   // We have a special root FixedArray with the right shape and values
   // to represent the cleared optimized code map. This predicate checks
   // if that root is installed.
   inline bool OptimizedCodeMapIsCleared() const;
 
   // Removes a specific optimized code object from the optimized code map.
   // In case of non-OSR the code reference is cleared from the cache entry but
   // the entry itself is left in the map in order to proceed sharing literals.
   void EvictFromOptimizedCodeMap(Code* optimized_code, const char* reason);
 
   // Trims the optimized code map after entries have been removed.
   void TrimOptimizedCodeMap(int shrink_by);
 
+  static Handle<LiteralsArray> FindOrCreateLiterals(
+      Handle<SharedFunctionInfo> shared, Handle<Context> native_context);
+
   // Add a new entry to the optimized code map for context-independent code.
   static void AddSharedCodeToOptimizedCodeMap(Handle<SharedFunctionInfo> shared,
                                               Handle<Code> code);
 
   // Add a new entry to the optimized code map for context-dependent code.
   inline static void AddToOptimizedCodeMap(Handle<SharedFunctionInfo> shared,
                                            Handle<Context> native_context,
                                            Handle<Code> code,
                                            Handle<LiteralsArray> literals,
                                            BailoutId osr_ast_id);
@@ skipping 14 matching lines @@
   static const int kEntriesStart = 1;
   static const int kContextOffset = 0;
   static const int kCachedCodeOffset = 1;
   static const int kLiteralsOffset = 2;
   static const int kOsrAstIdOffset = 3;
   static const int kEntryLength = 4;
   static const int kInitialLength = kEntriesStart + kEntryLength;
 
   static const int kNotFound = -1;
 
+  // Helpers for assembly code that does a backwards walk of the optimized code
+  // map.
+  static inline int OffsetToPreviousContext();
+  static inline int OffsetToPreviousCachedCode();
+  static inline int OffsetToPreviousLiterals();
+  static inline int OffsetToPreviousOsrAstId();
+
   // [scope_info]: Scope info.
   DECL_ACCESSORS(scope_info, ScopeInfo)
 
   // [construct stub]: Code stub for constructing instances of this function.
   DECL_ACCESSORS(construct_stub, Code)
 
   // Returns if this function has been compiled to native code yet.
   inline bool is_compiled();
 
   // [length]: The function length - usually the number of declared parameters.
   // Use up to 2^30 parameters.
   inline int length() const;
   inline void set_length(int value);
 
   // [internal formal parameter count]: The declared number of parameters.
   // For subclass constructors, also includes new.target.
   // The size of function's frame is internal_formal_parameter_count + 1.
   inline int internal_formal_parameter_count() const;
   inline void set_internal_formal_parameter_count(int value);
 
   // Set the formal parameter count so the function code will be
   // called without using argument adaptor frames.
   inline void DontAdaptArguments();
 
   // [expected_nof_properties]: Expected number of properties for the function.
   inline int expected_nof_properties() const;
   inline void set_expected_nof_properties(int value);
 
-  // [feedback_vector] - accumulates ast node feedback from full-codegen and
+  // [feedback_metadata] - describes ast node feedback from full-codegen and
   // (increasingly) from crankshafted code where sufficient feedback isn't
   // available.
-  DECL_ACCESSORS(feedback_vector, TypeFeedbackVector)
-
-  // Unconditionally clear the type feedback vector (including vector ICs).
-  void ClearTypeFeedbackInfo();
-
-  // Clear the type feedback vector with a more subtle policy at GC time.
-  void ClearTypeFeedbackInfoAtGCTime();
+  DECL_ACCESSORS(feedback_metadata, TypeFeedbackMetadata)
 
 #if TRACE_MAPS
   // [unique_id] - For --trace-maps purposes, an identifier that's persistent
   // even if the GC moves this SharedFunctionInfo.
   inline int unique_id() const;
   inline void set_unique_id(int value);
 #endif
 
   // [instance class name]: class name for instances.
   DECL_ACCESSORS(instance_class_name, Object)
@@ skipping 273 matching lines @@
   static const int kOptimizedCodeMapOffset = kCodeOffset + kPointerSize;
   static const int kScopeInfoOffset = kOptimizedCodeMapOffset + kPointerSize;
   static const int kConstructStubOffset = kScopeInfoOffset + kPointerSize;
   static const int kInstanceClassNameOffset =
       kConstructStubOffset + kPointerSize;
   static const int kFunctionDataOffset =
       kInstanceClassNameOffset + kPointerSize;
   static const int kScriptOffset = kFunctionDataOffset + kPointerSize;
   static const int kDebugInfoOffset = kScriptOffset + kPointerSize;
   static const int kInferredNameOffset = kDebugInfoOffset + kPointerSize;
-  static const int kFeedbackVectorOffset =
-      kInferredNameOffset + kPointerSize;
+  static const int kFeedbackMetadataOffset = kInferredNameOffset + kPointerSize;
 #if TRACE_MAPS
-  static const int kUniqueIdOffset = kFeedbackVectorOffset + kPointerSize;
+  static const int kUniqueIdOffset = kFeedbackMetadataOffset + kPointerSize;
   static const int kLastPointerFieldOffset = kUniqueIdOffset;
 #else
   // Just to not break the postmortrem support with conditional offsets
-  static const int kUniqueIdOffset = kFeedbackVectorOffset;
-  static const int kLastPointerFieldOffset = kFeedbackVectorOffset;
+  static const int kUniqueIdOffset = kFeedbackMetadataOffset;
+  static const int kLastPointerFieldOffset = kFeedbackMetadataOffset;
 #endif
 
 #if V8_HOST_ARCH_32_BIT
   // Smi fields.
   static const int kLengthOffset = kLastPointerFieldOffset + kPointerSize;
   static const int kFormalParameterCountOffset = kLengthOffset + kPointerSize;
   static const int kExpectedNofPropertiesOffset =
       kFormalParameterCountOffset + kPointerSize;
   static const int kNumLiteralsOffset =
       kExpectedNofPropertiesOffset + kPointerSize;
@@ skipping 404 matching lines @@
   static Handle<Context> GetFunctionRealm(Handle<JSFunction> function);
 
   // [code]: The generated code object for this function.  Executed
   // when the function is invoked, e.g. foo() or new foo(). See
   // [[Call]] and [[Construct]] description in ECMA-262, section
   // 8.6.2, page 27.
   inline Code* code();
   inline void set_code(Code* code);
   inline void set_code_no_write_barrier(Code* code);
   inline void ReplaceCode(Code* code);
+  static void EnsureLiterals(Handle<JSFunction> function);
 
   // Tells whether this function inlines the given shared function info.
   bool Inlines(SharedFunctionInfo* candidate);
 
   // Tells whether or not this function has been optimized.
   inline bool IsOptimized();
 
   // Mark this function for lazy recompilation. The function will be
   // recompiled the next time it is executed.
   void MarkForOptimization();
   void AttemptConcurrentOptimization();
 
   // Tells whether or not the function is already marked for lazy
   // recompilation.
   inline bool IsMarkedForOptimization();
   inline bool IsMarkedForConcurrentOptimization();
 
   // Tells whether or not the function is on the concurrent recompilation queue.
   inline bool IsInOptimizationQueue();
 
+  // Unconditionally clear the type feedback vector (including vector ICs).
+  void ClearTypeFeedbackInfo();
+
+  // Clear the type feedback vector with a more subtle policy at GC time.
+  void ClearTypeFeedbackInfoAtGCTime();
+
   // Completes inobject slack tracking on initial map if it is active.
   inline void CompleteInobjectSlackTrackingIfActive();
 
   // [literals]: Fixed array holding the materialized literals.
   //
   // If the function contains object, regexp or array literals, the
   // literals array prefix contains the object, regexp, and array
   // function to be used when creating these literals.  This is
   // necessary so that we do not dynamically lookup the object, regexp
   // or array functions.  Performing a dynamic lookup, we might end up
   // using the functions from a new context that we should not have
   // access to.
   DECL_ACCESSORS(literals, LiteralsArray)
 
+  inline TypeFeedbackVector* feedback_vector();
+
   // The initial map for an object created by this constructor.
   inline Map* initial_map();
   static void SetInitialMap(Handle<JSFunction> function, Handle<Map> map,
                             Handle<Object> prototype);
   inline bool has_initial_map();
   static void EnsureHasInitialMap(Handle<JSFunction> function);
 
   // Creates a map that matches the constructor's initial map, but with
   // [[prototype]] being new.target.prototype. Because new.target can be a
   // JSProxy, this can call back into JavaScript.
@@ skipping 3396 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_