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 #include "src/compiler/js-builtin-reducer.h" 6 #include "src/compiler/js-graph.h" 7 #include "src/compiler/node-matchers.h" 8 #include "src/compiler/node-properties.h" 9 #include "src/compiler/simplified-operator.h" 10 #include "src/objects-inl.h" 11 #include "src/types.h" 12 13 namespace v8 { 14 namespace internal { 15 namespace compiler { 16 17 18 // Helper class to access JSCallFunction nodes that are potential candidates 19 // for reduction when they have a BuiltinFunctionId associated with them. 20 class JSCallReduction { 21 public: 22 explicit JSCallReduction(Node* node) : node_(node) {} 23 24 // Determines whether the node is a JSCallFunction operation that targets a 25 // constant callee being a well-known builtin with a BuiltinFunctionId. 26 bool HasBuiltinFunctionId() { 27 if (node_->opcode() != IrOpcode::kJSCallFunction) return false; 28 HeapObjectMatcher m(NodeProperties::GetValueInput(node_, 0)); 29 if (!m.HasValue() || !m.Value()->IsJSFunction()) return false; 30 Handle<JSFunction> function = Handle<JSFunction>::cast(m.Value()); 31 return function->shared()->HasBuiltinFunctionId(); 32 } 33 34 // Retrieves the BuiltinFunctionId as described above. 35 BuiltinFunctionId GetBuiltinFunctionId() { 36 DCHECK_EQ(IrOpcode::kJSCallFunction, node_->opcode()); 37 HeapObjectMatcher m(NodeProperties::GetValueInput(node_, 0)); 38 Handle<JSFunction> function = Handle<JSFunction>::cast(m.Value()); 39 return function->shared()->builtin_function_id(); 40 } 41 42 // Determines whether the call takes zero inputs. 43 bool InputsMatchZero() { return GetJSCallArity() == 0; } 44 45 // Determines whether the call takes one input of the given type. 46 bool InputsMatchOne(Type* t1) { 47 return GetJSCallArity() == 1 && 48 NodeProperties::GetType(GetJSCallInput(0))->Is(t1); 49 } 50 51 // Determines whether the call takes two inputs of the given types. 52 bool InputsMatchTwo(Type* t1, Type* t2) { 53 return GetJSCallArity() == 2 && 54 NodeProperties::GetType(GetJSCallInput(0))->Is(t1) && 55 NodeProperties::GetType(GetJSCallInput(1))->Is(t2); 56 } 57 58 // Determines whether the call takes inputs all of the given type. 59 bool InputsMatchAll(Type* t) { 60 for (int i = 0; i < GetJSCallArity(); i++) { 61 if (!NodeProperties::GetType(GetJSCallInput(i))->Is(t)) { 62 return false; 63 } 64 } 65 return true; 66 } 67 68 Node* left() { return GetJSCallInput(0); } 69 Node* right() { return GetJSCallInput(1); } 70 71 int GetJSCallArity() { 72 DCHECK_EQ(IrOpcode::kJSCallFunction, node_->opcode()); 73 // Skip first (i.e. callee) and second (i.e. receiver) operand. 74 return node_->op()->ValueInputCount() - 2; 75 } 76 77 Node* GetJSCallInput(int index) { 78 DCHECK_EQ(IrOpcode::kJSCallFunction, node_->opcode()); 79 DCHECK_LT(index, GetJSCallArity()); 80 // Skip first (i.e. callee) and second (i.e. receiver) operand. 81 return NodeProperties::GetValueInput(node_, index + 2); 82 } 83 84 private: 85 Node* node_; 86 }; 87 88 89 JSBuiltinReducer::JSBuiltinReducer(Editor* editor, JSGraph* jsgraph) 90 : AdvancedReducer(editor), jsgraph_(jsgraph) {} 91 92 93 // ECMA-262, section 15.8.2.11. 94 Reduction JSBuiltinReducer::ReduceMathMax(Node* node) { 95 JSCallReduction r(node); 96 if (r.InputsMatchZero()) { 97 // Math.max() -> -Infinity 98 return Replace(jsgraph()->Constant(-V8_INFINITY)); 99 } 100 if (r.InputsMatchOne(Type::Number())) { 101 // Math.max(a:number) -> a 102 return Replace(r.left()); 103 } 104 if (r.InputsMatchAll(Type::Integral32())) { 105 // Math.max(a:int32, b:int32, ...) 106 Node* value = r.GetJSCallInput(0); 107 for (int i = 1; i < r.GetJSCallArity(); i++) { 108 Node* const input = r.GetJSCallInput(i); 109 value = graph()->NewNode( 110 common()->Select(MachineRepresentation::kNone), 111 graph()->NewNode(simplified()->NumberLessThan(), input, value), value, 112 input); 113 } 114 return Replace(value); 115 } 116 return NoChange(); 117 } 118 119 120 // ES6 draft 08-24-14, section 20.2.2.19. 121 Reduction JSBuiltinReducer::ReduceMathImul(Node* node) { 122 JSCallReduction r(node); 123 if (r.InputsMatchTwo(Type::Integral32(), Type::Integral32())) { 124 // Math.imul(a:int32, b:int32) -> Int32Mul(a, b) 125 Node* value = graph()->NewNode(machine()->Int32Mul(), r.left(), r.right()); 126 return Replace(value); 127 } 128 return NoChange(); 129 } 130 131 132 // ES6 draft 08-24-14, section 20.2.2.17. 133 Reduction JSBuiltinReducer::ReduceMathFround(Node* node) { 134 JSCallReduction r(node); 135 if (r.InputsMatchOne(Type::Number())) { 136 // Math.fround(a:number) -> TruncateFloat64ToFloat32(a) 137 Node* value = 138 graph()->NewNode(machine()->TruncateFloat64ToFloat32(), r.left()); 139 return Replace(value); 140 } 141 return NoChange(); 142 } 143 144 145 Reduction JSBuiltinReducer::Reduce(Node* node) { 146 Reduction reduction = NoChange(); 147 JSCallReduction r(node); 148 149 // Dispatch according to the BuiltinFunctionId if present. 150 if (!r.HasBuiltinFunctionId()) return NoChange(); 151 switch (r.GetBuiltinFunctionId()) { 152 case kMathMax: 153 reduction = ReduceMathMax(node); 154 break; 155 case kMathImul: 156 reduction = ReduceMathImul(node); 157 break; 158 case kMathFround: 159 reduction = ReduceMathFround(node); 160 break; 161 default: 162 break; 163 } 164 165 // Replace builtin call assuming replacement nodes are pure values that don't 166 // produce an effect. Replaces {node} with {reduction} and relaxes effects. 167 if (reduction.Changed()) ReplaceWithValue(node, reduction.replacement()); 168 169 return reduction; 170 } 171 172 173 Graph* JSBuiltinReducer::graph() const { return jsgraph()->graph(); } 174 175 176 Isolate* JSBuiltinReducer::isolate() const { return jsgraph()->isolate(); } 177 178 179 CommonOperatorBuilder* JSBuiltinReducer::common() const { 180 return jsgraph()->common(); 181 } 182 183 184 MachineOperatorBuilder* JSBuiltinReducer::machine() const { 185 return jsgraph()->machine(); 186 } 187 188 189 SimplifiedOperatorBuilder* JSBuiltinReducer::simplified() const { 190 return jsgraph()->simplified(); 191 } 192 193 } // namespace compiler 194 } // namespace internal 195 } // namespace v8 196