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Current view: top level - src/compiler - js-type-hint-lowering.h (source / functions) Hit Total Coverage
Test: app.info Lines: 1 1 100.0 %
Date: 2019-04-17 Functions: 0 0 -

          Line data    Source code
       1             : // Copyright 2017 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_TYPE_HINT_LOWERING_H_
       6             : #define V8_COMPILER_JS_TYPE_HINT_LOWERING_H_
       7             : 
       8             : #include "src/base/flags.h"
       9             : #include "src/compiler/graph-reducer.h"
      10             : #include "src/deoptimize-reason.h"
      11             : #include "src/handles.h"
      12             : 
      13             : namespace v8 {
      14             : namespace internal {
      15             : 
      16             : // Forward declarations.
      17             : class FeedbackNexus;
      18             : class FeedbackSlot;
      19             : 
      20             : namespace compiler {
      21             : 
      22             : // Forward declarations.
      23             : class JSGraph;
      24             : class Node;
      25             : class Operator;
      26             : 
      27             : // The type-hint lowering consumes feedback about high-level operations in order
      28             : // to potentially emit nodes using speculative simplified operators in favor of
      29             : // the generic JavaScript operators.
      30             : //
      31             : // This lowering is implemented as an early reduction and can be applied before
      32             : // nodes are placed into the initial graph. It provides the ability to shortcut
      33             : // the JavaScript-level operators and directly emit simplified-level operators
      34             : // even during initial graph building. This is the reason this lowering doesn't
      35             : // follow the interface of the reducer framework used after graph construction.
      36             : // The result of the lowering is encapsulated in
      37             : // {the JSTypeHintLowering::LoweringResult} class.
      38             : class JSTypeHintLowering {
      39             :  public:
      40             :   // Flags that control the mode of operation.
      41             :   enum Flag { kNoFlags = 0u, kBailoutOnUninitialized = 1u << 1 };
      42             :   using Flags = base::Flags<Flag>;
      43             : 
      44             :   JSTypeHintLowering(JSGraph* jsgraph, Handle<FeedbackVector> feedback_vector,
      45             :                      Flags flags);
      46             : 
      47             :   // {LoweringResult} describes the result of lowering. The following outcomes
      48             :   // are possible:
      49             :   //
      50             :   // - operation was lowered to a side-effect-free operation, the resulting
      51             :   //   value, effect and control can be obtained by the {value}, {effect} and
      52             :   //   {control} methods.
      53             :   //
      54             :   // - operation was lowered to a graph exit (deoptimization). The caller
      55             :   //   should connect {effect} and {control} nodes to the end.
      56             :   //
      57             :   // - no lowering happened. The caller needs to create the generic version
      58             :   //   of the operation.
      59             :   class LoweringResult {
      60             :    public:
      61             :     Node* value() const { return value_; }
      62             :     Node* effect() const { return effect_; }
      63             :     Node* control() const { return control_; }
      64             : 
      65             :     bool Changed() const { return kind_ != LoweringResultKind::kNoChange; }
      66             :     bool IsExit() const { return kind_ == LoweringResultKind::kExit; }
      67             :     bool IsSideEffectFree() const {
      68             :       return kind_ == LoweringResultKind::kSideEffectFree;
      69             :     }
      70             : 
      71             :     static LoweringResult SideEffectFree(Node* value, Node* effect,
      72             :                                          Node* control) {
      73             :       DCHECK_NOT_NULL(effect);
      74             :       DCHECK_NOT_NULL(control);
      75             :       return LoweringResult(LoweringResultKind::kSideEffectFree, value, effect,
      76             :                             control);
      77             :     }
      78             : 
      79             :     static LoweringResult NoChange() {
      80             :       return LoweringResult(LoweringResultKind::kNoChange, nullptr, nullptr,
      81             :                             nullptr);
      82             :     }
      83             : 
      84             :     static LoweringResult Exit(Node* control) {
      85             :       return LoweringResult(LoweringResultKind::kExit, nullptr, nullptr,
      86             :                             control);
      87             :     }
      88             : 
      89             :    private:
      90             :     enum class LoweringResultKind { kNoChange, kSideEffectFree, kExit };
      91             : 
      92             :     LoweringResult(LoweringResultKind kind, Node* value, Node* effect,
      93             :                    Node* control)
      94      725729 :         : kind_(kind), value_(value), effect_(effect), control_(control) {}
      95             : 
      96             :     LoweringResultKind kind_;
      97             :     Node* value_;
      98             :     Node* effect_;
      99             :     Node* control_;
     100             :   };
     101             : 
     102             :   // Potential reduction of unary operations (e.g. negation).
     103             :   LoweringResult ReduceUnaryOperation(const Operator* op, Node* operand,
     104             :                                       Node* effect, Node* control,
     105             :                                       FeedbackSlot slot) const;
     106             : 
     107             :   // Potential reduction of binary (arithmetic, logical, shift and relational
     108             :   // comparison) operations.
     109             :   LoweringResult ReduceBinaryOperation(const Operator* op, Node* left,
     110             :                                        Node* right, Node* effect, Node* control,
     111             :                                        FeedbackSlot slot) const;
     112             : 
     113             :   // Potential reduction to for..in operations
     114             :   LoweringResult ReduceForInNextOperation(Node* receiver, Node* cache_array,
     115             :                                           Node* cache_type, Node* index,
     116             :                                           Node* effect, Node* control,
     117             :                                           FeedbackSlot slot) const;
     118             :   LoweringResult ReduceForInPrepareOperation(Node* enumerator, Node* effect,
     119             :                                              Node* control,
     120             :                                              FeedbackSlot slot) const;
     121             : 
     122             :   // Potential reduction to ToNumber operations
     123             :   LoweringResult ReduceToNumberOperation(Node* value, Node* effect,
     124             :                                          Node* control,
     125             :                                          FeedbackSlot slot) const;
     126             : 
     127             :   // Potential reduction of call operations.
     128             :   LoweringResult ReduceCallOperation(const Operator* op, Node* const* args,
     129             :                                      int arg_count, Node* effect, Node* control,
     130             :                                      FeedbackSlot slot) const;
     131             : 
     132             :   // Potential reduction of construct operations.
     133             :   LoweringResult ReduceConstructOperation(const Operator* op, Node* const* args,
     134             :                                           int arg_count, Node* effect,
     135             :                                           Node* control,
     136             :                                           FeedbackSlot slot) const;
     137             :   // Potential reduction of property access operations.
     138             :   LoweringResult ReduceLoadNamedOperation(const Operator* op, Node* obj,
     139             :                                           Node* effect, Node* control,
     140             :                                           FeedbackSlot slot) const;
     141             :   LoweringResult ReduceLoadKeyedOperation(const Operator* op, Node* obj,
     142             :                                           Node* key, Node* effect,
     143             :                                           Node* control,
     144             :                                           FeedbackSlot slot) const;
     145             :   LoweringResult ReduceStoreNamedOperation(const Operator* op, Node* obj,
     146             :                                            Node* val, Node* effect,
     147             :                                            Node* control,
     148             :                                            FeedbackSlot slot) const;
     149             :   LoweringResult ReduceStoreKeyedOperation(const Operator* op, Node* obj,
     150             :                                            Node* key, Node* val, Node* effect,
     151             :                                            Node* control,
     152             :                                            FeedbackSlot slot) const;
     153             : 
     154             :  private:
     155             :   friend class JSSpeculativeBinopBuilder;
     156             :   Node* TryBuildSoftDeopt(FeedbackNexus& nexus, Node* effect, Node* control,
     157             :                           DeoptimizeReason reson) const;
     158             : 
     159             :   JSGraph* jsgraph() const { return jsgraph_; }
     160             :   Isolate* isolate() const;
     161             :   Flags flags() const { return flags_; }
     162             :   const Handle<FeedbackVector>& feedback_vector() const {
     163             :     return feedback_vector_;
     164             :   }
     165             : 
     166             :   JSGraph* jsgraph_;
     167             :   Flags const flags_;
     168             :   Handle<FeedbackVector> feedback_vector_;
     169             : 
     170             :   DISALLOW_COPY_AND_ASSIGN(JSTypeHintLowering);
     171             : };
     172             : 
     173             : }  // namespace compiler
     174             : }  // namespace internal
     175             : }  // namespace v8
     176             : 
     177             : #endif  // V8_COMPILER_JS_TYPE_HINT_LOWERING_H_

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