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      1 // Copyright 2015 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-frame-specialization.h"
      6 
      7 #include "src/compiler/js-graph.h"
      8 #include "src/compiler/linkage.h"
      9 #include "src/frames-inl.h"
     10 
     11 namespace v8 {
     12 namespace internal {
     13 namespace compiler {
     14 
     15 Reduction JSFrameSpecialization::Reduce(Node* node) {
     16   switch (node->opcode()) {
     17     case IrOpcode::kOsrValue:
     18       return ReduceOsrValue(node);
     19     case IrOpcode::kParameter:
     20       return ReduceParameter(node);
     21     default:
     22       break;
     23   }
     24   return NoChange();
     25 }
     26 
     27 
     28 Reduction JSFrameSpecialization::ReduceOsrValue(Node* node) {
     29   DCHECK_EQ(IrOpcode::kOsrValue, node->opcode());
     30   Handle<Object> value;
     31   int const index = OpParameter<int>(node);
     32   int const parameters_count = frame()->ComputeParametersCount() + 1;
     33   if (index == Linkage::kOsrContextSpillSlotIndex) {
     34     value = handle(frame()->context(), isolate());
     35   } else if (index >= parameters_count) {
     36     value = handle(frame()->GetExpression(index - parameters_count), isolate());
     37   } else {
     38     // The OsrValue index 0 is the receiver.
     39     value =
     40         handle(index ? frame()->GetParameter(index - 1) : frame()->receiver(),
     41                isolate());
     42   }
     43   return Replace(jsgraph()->Constant(value));
     44 }
     45 
     46 
     47 Reduction JSFrameSpecialization::ReduceParameter(Node* node) {
     48   DCHECK_EQ(IrOpcode::kParameter, node->opcode());
     49   Handle<Object> value;
     50   int const index = ParameterIndexOf(node->op());
     51   int const parameters_count = frame()->ComputeParametersCount() + 1;
     52   if (index == Linkage::kJSCallClosureParamIndex) {
     53     // The Parameter index references the closure.
     54     value = handle(frame()->function(), isolate());
     55   } else if (index == Linkage::GetJSCallArgCountParamIndex(parameters_count)) {
     56     // The Parameter index references the parameter count.
     57     value = handle(Smi::FromInt(parameters_count - 1), isolate());
     58   } else if (index == Linkage::GetJSCallContextParamIndex(parameters_count)) {
     59     // The Parameter index references the context.
     60     value = handle(frame()->context(), isolate());
     61   } else {
     62     // The Parameter index 0 is the receiver.
     63     value =
     64         handle(index ? frame()->GetParameter(index - 1) : frame()->receiver(),
     65                isolate());
     66   }
     67   return Replace(jsgraph()->Constant(value));
     68 }
     69 
     70 
     71 Isolate* JSFrameSpecialization::isolate() const { return jsgraph()->isolate(); }
     72 
     73 }  // namespace compiler
     74 }  // namespace internal
     75 }  // namespace v8
     76