Line data    Source code

       1             : // Copyright 2014 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #ifndef V8_COMPILER_JS_CONTEXT_SPECIALIZATION_H_
       6             : #define V8_COMPILER_JS_CONTEXT_SPECIALIZATION_H_
       7             : 
       8             : #include "src/compiler/graph-reducer.h"
       9             : 
      10             : namespace v8 {
      11             : namespace internal {
      12             : namespace compiler {
      13             : 
      14             : // Forward declarations.
      15             : class JSGraph;
      16             : class JSOperatorBuilder;
      17             : 
      18             : // Pair of a context and its distance from some point of reference.
      19             : struct OuterContext {
      20       23124 :   OuterContext() : context(), distance() {}
      21             :   OuterContext(Handle<Context> context_, size_t distance_)
      22             :       : context(context_), distance(distance_) {}
      23             :   Handle<Context> context;
      24             :   size_t distance;
      25             : };
      26             : 
      27             : // Specializes a given JSGraph to a given context, potentially constant folding
      28             : // some {LoadContext} nodes or strength reducing some {StoreContext} nodes.
      29             : // Additionally, constant-folds the function parameter if {closure} is given.
      30             : //
      31             : // The context can be the incoming function context or any outer context
      32             : // thereof, as indicated by {outer}'s {distance}.
      33      443430 : class JSContextSpecialization final : public AdvancedReducer {
      34             :  public:
      35             :   JSContextSpecialization(Editor* editor, JSGraph* jsgraph,
      36             :                           Maybe<OuterContext> outer,
      37             :                           MaybeHandle<JSFunction> closure)
      38             :       : AdvancedReducer(editor),
      39             :         jsgraph_(jsgraph),
      40             :         outer_(outer),
      41      443430 :         closure_(closure) {}
      42             : 
      43           0 :   const char* reducer_name() const override {
      44           0 :     return "JSContextSpecialization";
      45             :   }
      46             : 
      47             :   Reduction Reduce(Node* node) final;
      48             : 
      49             :  private:
      50             :   Reduction ReduceParameter(Node* node);
      51             :   Reduction ReduceJSLoadContext(Node* node);
      52             :   Reduction ReduceJSStoreContext(Node* node);
      53             : 
      54             :   Reduction SimplifyJSStoreContext(Node* node, Node* new_context,
      55             :                                    size_t new_depth);
      56             :   Reduction SimplifyJSLoadContext(Node* node, Node* new_context,
      57             :                                   size_t new_depth);
      58             : 
      59             :   Isolate* isolate() const;
      60             :   JSGraph* jsgraph() const { return jsgraph_; }
      61     1035924 :   Maybe<OuterContext> outer() const { return outer_; }
      62             :   MaybeHandle<JSFunction> closure() const { return closure_; }
      63             : 
      64             :   JSGraph* const jsgraph_;
      65             :   Maybe<OuterContext> outer_;
      66             :   MaybeHandle<JSFunction> closure_;
      67             : 
      68             :   DISALLOW_COPY_AND_ASSIGN(JSContextSpecialization);
      69             : };
      70             : 
      71             : }  // namespace compiler
      72             : }  // namespace internal
      73             : }  // namespace v8
      74             : 
      75             : #endif  // V8_COMPILER_JS_CONTEXT_SPECIALIZATION_H_