[turbofan] Implement sharing of context-independent code.

src/objects.h

 // 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.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 6536 matching lines @@
   FUNCTIONS_WITH_ID_LIST(DECLARE_FUNCTION_ID)
       ATOMIC_FUNCTIONS_WITH_ID_LIST(DECLARE_FUNCTION_ID)
 #undef DECLARE_FUNCTION_ID
   // Fake id for a special case of Math.pow. Note, it continues the
   // list of math functions.
   kMathPowHalf
 };
 
 
 // Result of searching in an optimized code map of a SharedFunctionInfo. Note
-// that {code == nullptr} indicates that no entry has been found.
+// that both {code} and {literals} can be NULL to pass search result status.
 struct CodeAndLiterals {
   Code* code;            // Cached optimized code.
   FixedArray* 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)
   inline void ReplaceCode(Code* code);
 
   // [optimized_code_map]: Map from native context to optimized code
   // and a shared literals array or Smi(0) if none.
   DECL_ACCESSORS(optimized_code_map, Object)
 
   // Returns entry from optimized code map for specified context and OSR entry.
-  // Note that {code == nullptr} indicates no matching entry has been found.
+  // Note that {code == nullptr} indicates no matching entry has been found,
+  // whereas {literals == nullptr} indicates the code is context-independent.
   CodeAndLiterals SearchOptimizedCodeMap(Context* native_context,
                                          BailoutId osr_ast_id);
 
   // Clear optimized code map.
   void ClearOptimizedCodeMap();
 
   // Removed a specific optimized code object from the optimized code map.
   void EvictFromOptimizedCodeMap(Code* optimized_code, const char* reason);
 
-  // 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();
-
   // Trims the optimized code map after entries have been removed.
   void TrimOptimizedCodeMap(int shrink_by);
 
-  // Initialize a SharedFunctionInfo from a parsed function literal.
-  static void InitFromFunctionLiteral(Handle<SharedFunctionInfo> shared_info,
-                                      FunctionLiteral* lit);
+  // 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.
+  // Add a new entry to the optimized code map for context-dependent code.
   static void AddToOptimizedCodeMap(Handle<SharedFunctionInfo> shared,
                                     Handle<Context> native_context,
                                     Handle<Code> code,
                                     Handle<FixedArray> 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.
   static void SetScript(Handle<SharedFunctionInfo> shared,
                         Handle<Object> script_object);
 
   // Layout description of the optimized code map.
   static const int kNextMapIndex = 0;
-  static const int kEntriesStart = 1;
+  static const int kSharedCodeIndex = 1;
+  static const int kEntriesStart = 2;
   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;
 
   // [scope_info]: Scope info.
   DECL_ACCESSORS(scope_info, ScopeInfo)
 
@@ skipping 20 matching lines @@
 
   // [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
   // (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();
+
 #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 222 matching lines @@
   int SourceSize();
 
   // Calculate the instance size.
   int CalculateInstanceSize();
 
   // Calculate the number of in-object properties.
   int CalculateInObjectProperties();
 
   inline bool is_simple_parameter_list();
 
+  // Initialize a SharedFunctionInfo from a parsed function literal.
+  static void InitFromFunctionLiteral(Handle<SharedFunctionInfo> shared_info,
+                                      FunctionLiteral* lit);
+
   // Dispatched behavior.
   DECLARE_PRINTER(SharedFunctionInfo)
   DECLARE_VERIFIER(SharedFunctionInfo)
 
   void ResetForNewContext(int new_ic_age);
 
   DECLARE_CAST(SharedFunctionInfo)
 
   // Constants.
   static const int kDontAdaptArgumentsSentinel = -1;
@@ skipping 3899 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_