[Atomics] Make Atomics.exchange a builtin using TF

src/compiler/machine-operator.h

 // Copyright 2013 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.
 
 #ifndef V8_COMPILER_MACHINE_OPERATOR_H_
 #define V8_COMPILER_MACHINE_OPERATOR_H_
 
 #include "src/base/compiler-specific.h"
 #include "src/base/flags.h"
 #include "src/globals.h"
@@ skipping 79 matching lines @@
 
 // A CheckedStore needs a MachineType.
 typedef MachineRepresentation CheckedStoreRepresentation;
 
 CheckedStoreRepresentation CheckedStoreRepresentationOf(Operator const*);
 
 MachineRepresentation StackSlotRepresentationOf(Operator const* op);
 
 MachineRepresentation AtomicStoreRepresentationOf(Operator const* op);
 
+MachineType AtomicExchangeRepresentationOf(Operator const* op);
+
 // Interface for building machine-level operators. These operators are
 // machine-level but machine-independent and thus define a language suitable
 // for generating code to run on architectures such as ia32, x64, arm, etc.
 class V8_EXPORT_PRIVATE MachineOperatorBuilder final
     : public NON_EXPORTED_BASE(ZoneObject) {
  public:
   // Flags that specify which operations are available. This is useful
   // for operations that are unsupported by some back-ends.
   enum Flag : unsigned {
     kNoFlags = 0u,
@@ skipping 518 matching lines @@
 
   // checked-load heap, index, length
   const Operator* CheckedLoad(CheckedLoadRepresentation);
   // checked-store heap, index, length, value
   const Operator* CheckedStore(CheckedStoreRepresentation);
 
   // atomic-load [base + index]
   const Operator* AtomicLoad(LoadRepresentation rep);
   // atomic-store [base + index], value
   const Operator* AtomicStore(MachineRepresentation rep);
+  // atomic-exchange [base + index], value
+  const Operator* AtomicExchange(MachineType rep);
 
   // Target machine word-size assumed by this builder.
   bool Is32() const { return word() == MachineRepresentation::kWord32; }
   bool Is64() const { return word() == MachineRepresentation::kWord64; }
   MachineRepresentation word() const { return word_; }
 
   bool UnalignedLoadSupported(const MachineType& machineType,
                               uint8_t alignment) {
     return alignment_requirements_.IsUnalignedLoadSupported(machineType,
                                                             alignment);
@@ skipping 46 matching lines @@
 };
 
 
 DEFINE_OPERATORS_FOR_FLAGS(MachineOperatorBuilder::Flags)
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_MACHINE_OPERATOR_H_