[strong] Disallow implicit conversions for add

src/compiler/js-typed-lowering.cc

 // Copyright 2014 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.
 
 #include "src/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 147 matching lines @@
       value->ReplaceInput(0, node_);
       return lowering_->Replace(value);
     }
     return lowering_->Changed(node_);
   }
 
   Reduction ChangeToPureOperator(const Operator* op, Type* type) {
     return ChangeToPureOperator(op, false, type);
   }
 
+  bool IsStrong() { return is_strong(OpParameter<LanguageMode>(node_)); }
+
   bool OneInputIs(Type* t) { return left_type()->Is(t) || right_type()->Is(t); }
 
   bool BothInputsAre(Type* t) {
     return left_type()->Is(t) && right_type()->Is(t);
   }
 
   bool OneInputCannotBe(Type* t) {
     return !left_type()->Maybe(t) || !right_type()->Maybe(t);
   }
 
@@ skipping 135 matching lines @@
   }
 };
 
 
 Reduction JSTypedLowering::ReduceJSAdd(Node* node) {
   JSBinopReduction r(this, node);
   if (r.BothInputsAre(Type::Number())) {
     // JSAdd(x:number, y:number) => NumberAdd(x, y)
     return r.ChangeToPureOperator(simplified()->NumberAdd(), Type::Number());
   }
-  if (r.NeitherInputCanBe(Type::StringOrReceiver())) {
+  if (r.NeitherInputCanBe(Type::StringOrReceiver()) && !r.IsStrong()) {
     // JSAdd(x:-string, y:-string) => NumberAdd(ToNumber(x), ToNumber(y))
     Node* frame_state = NodeProperties::GetFrameStateInput(node, 1);
     r.ConvertInputsToNumber(frame_state);
     return r.ChangeToPureOperator(simplified()->NumberAdd(), Type::Number());
   }
 #if 0
   // TODO(turbofan): Lowering of StringAdd is disabled for now because:
   //   a) The inserted ToString operation screws up valueOf vs. toString order.
   //   b) Deoptimization at ToString doesn't have corresponding bailout id.
   //   c) Our current StringAddStub is actually non-pure and requires context.
-  if (r.OneInputIs(Type::String())) {
+  if ((r.OneInputIs(Type::String()) && !r.IsStrong()) ||
+      r.BothInputsAre(Type::String())) {
     // JSAdd(x:string, y:string) => StringAdd(x, y)
     // JSAdd(x:string, y) => StringAdd(x, ToString(y))
     // JSAdd(x, y:string) => StringAdd(ToString(x), y)
     r.ConvertInputsToString();
     return r.ChangeToPureOperator(simplified()->StringAdd());
   }
 #endif
   return NoChange();
 }
 
 
 Reduction JSTypedLowering::ReduceNumberBinop(Node* node,
                                              const Operator* numberOp) {
   JSBinopReduction r(this, node);
-  if (is_strong(OpParameter<LanguageMode>(node))) {
+  if (r.IsStrong()) {
     if (r.BothInputsAre(Type::Number())) {
       return r.ChangeToPureOperator(numberOp, Type::Number());
     }
     return NoChange();
   }
   Node* frame_state = NodeProperties::GetFrameStateInput(node, 1);
   r.ConvertInputsToNumber(frame_state);
   return r.ChangeToPureOperator(numberOp, Type::Number());
 }
 
 
 Reduction JSTypedLowering::ReduceInt32Binop(Node* node, const Operator* intOp) {
   JSBinopReduction r(this, node);
-  if (is_strong(OpParameter<LanguageMode>(node))) {
+  if (r.IsStrong()) {
     if (r.BothInputsAre(Type::Number())) {
       r.ConvertInputsToUI32(kSigned, kSigned);
       return r.ChangeToPureOperator(intOp, Type::Integral32());
     }
     return NoChange();
   }
   Node* frame_state = NodeProperties::GetFrameStateInput(node, 1);
   r.ConvertInputsToNumber(frame_state);
   r.ConvertInputsToUI32(kSigned, kSigned);
   return r.ChangeToPureOperator(intOp, Type::Integral32());
 }
 
 
 Reduction JSTypedLowering::ReduceUI32Shift(Node* node,
                                            Signedness left_signedness,
                                            const Operator* shift_op) {
   JSBinopReduction r(this, node);
-  Type* reduce_type = is_strong(
-                        OpParameter<LanguageMode>(node)) ? Type::Number() :
-                                                           Type::Primitive();
+  Type* reduce_type = r.IsStrong() ? Type::Number() : Type::Primitive();
   if (r.BothInputsAre(reduce_type)) {
     r.ConvertInputsForShift(left_signedness);
     return r.ChangeToPureOperator(shift_op, Type::Integral32());
   }
   return NoChange();
 }
 
 
 Reduction JSTypedLowering::ReduceJSComparison(Node* node) {
   JSBinopReduction r(this, node);
@@ skipping 783 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSTypedLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8