Revert [TypeFeedbackVector] Root literal arrays in function literal slots

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 <memory>
 
@@ skipping 4979 matching lines @@
  public:
   static const int kVectorIndex = 0;
   static const int kFirstLiteralIndex = 1;
   V8_EXPORT_PRIVATE static const int kFeedbackVectorOffset;
   static const int kOffsetToFirstLiteral;
 
   static int OffsetOfLiteralAt(int index) {
     return OffsetOfElementAt(index + kFirstLiteralIndex);
   }
 
-  inline bool has_feedback_vector() const;
   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 = TENURED);
 
@@ skipping 2116 matching lines @@
   kTypedArrayByteOffset,
   kTypedArrayEntries,
   kTypedArrayKeys,
   kTypedArrayLength,
   kTypedArrayValues,
   kSharedArrayBufferByteLength,
   kStringIterator,
   kStringIteratorNext,
 };
 
+// Result of searching in an optimized code map of a SharedFunctionInfo. Note
+// that both {code} and {literals} can be NULL to pass search result status.
+struct CodeAndLiterals {
+  Code* code;               // Cached optimized code.
+  LiteralsArray* literals;  // Cached literals array.
+};
 
 // SharedFunctionInfo describes the JSFunction information that can be
 // shared by multiple instances of the function.
 class SharedFunctionInfo: public HeapObject {
  public:
   // [name]: Function name.
   DECL_ACCESSORS(name, Object)
 
   // [code]: Function code.
   DECL_ACCESSORS(code, Code)
@@ skipping 11 matching lines @@
   inline bool IsInterpreted() const;
 
   inline void ReplaceCode(Code* code);
   inline bool HasBaselineCode() const;
 
   // [optimized_code_map]: Map from native context to optimized code
   // and a shared literals array.
   DECL_ACCESSORS(optimized_code_map, FixedArray)
 
   // Returns entry from optimized code map for specified context and OSR entry.
-  Code* SearchOptimizedCodeMap(Context* native_context, BailoutId osr_ast_id);
+  // 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);
 
   static Handle<LiteralsArray> FindOrCreateLiterals(
       Handle<SharedFunctionInfo> shared, Handle<Context> native_context);
 
   // Add or update entry in the optimized code map for context-dependent code.
+  // If {code} is not given, then an existing entry's code won't be overwritten.
   static void AddToOptimizedCodeMap(Handle<SharedFunctionInfo> shared,
                                     Handle<Context> native_context,
-                                    Handle<Code> code, BailoutId osr_ast_id);
+                                    MaybeHandle<Code> code,
+                                    Handle<LiteralsArray> literals,
+                                    BailoutId osr_ast_id);
 
   // Set up the link between shared function info and the script. The shared
   // function info is added to the list on the script.
   V8_EXPORT_PRIVATE static void SetScript(Handle<SharedFunctionInfo> shared,
                                           Handle<Object> script_object);
 
   // Layout description of the optimized code map.
   static const int kEntriesStart = 0;
   static const int kContextOffset = 0;
   static const int kCachedCodeOffset = 1;
-  static const int kEntryLength = 2;
+  static const int kLiteralsOffset = 2;
+  static const int kEntryLength = 3;
   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 const int kOffsetToPreviousContext =
       FixedArray::kHeaderSize + kPointerSize * (kContextOffset - kEntryLength);
   static const int kOffsetToPreviousCachedCode =
       FixedArray::kHeaderSize +
       kPointerSize * (kCachedCodeOffset - kEntryLength);
+  static const int kOffsetToPreviousLiterals =
+      FixedArray::kHeaderSize + kPointerSize * (kLiteralsOffset - kEntryLength);
 
   // [scope_info]: Scope info.
   DECL_ACCESSORS(scope_info, ScopeInfo)
 
   // The outer scope info for the purpose of parsing this function, or the hole
   // value if it isn't yet known.
   DECL_ACCESSORS(outer_scope_info, HeapObject)
 
   // [construct stub]: Code stub for constructing instances of this function.
   DECL_ACCESSORS(construct_stub, Code)
@@ skipping 929 matching lines @@
   //
   // 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. For API objects we store the boilerplate in the literal array.
   DECL_ACCESSORS(literals, LiteralsArray)
 
-  inline bool has_literals_array() const;
   static void EnsureLiterals(Handle<JSFunction> function);
   inline TypeFeedbackVector* feedback_vector();
 
   // 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();
 
   // The initial map for an object created by this constructor.
@@ skipping 3509 matching lines @@
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #include "src/objects/object-macros-undef.h"
 
 #endif  // V8_OBJECTS_H_