[Atomics] Make Atomics.exchange a builtin using TF

src/compiler/arm/instruction-selector-arm.cc

Index: src/compiler/arm/instruction-selector-arm.cc
diff --git a/src/compiler/arm/instruction-selector-arm.cc b/src/compiler/arm/instruction-selector-arm.cc
index da99db1049ba0de336f9e4e1863fd53a51e9c21f..a2d83e6db21e03d776d5f54906561134884401ab 100644
--- a/src/compiler/arm/instruction-selector-arm.cc
+++ b/src/compiler/arm/instruction-selector-arm.cc
@@ -2181,6 +2181,42 @@ void InstructionSelector::VisitAtomicStore(Node* node) {
   Emit(code, 0, nullptr, input_count, inputs);
 }
 
+void InstructionSelector::VisitAtomicExchange(Node* node) {
+  ArmOperandGenerator g(this);
+  Node* base = node->InputAt(0);
+  Node* index = node->InputAt(1);
+  Node* value = node->InputAt(2);
+  ArchOpcode opcode = kArchNop;
+  MachineType type = AtomicExchangeRepresentationOf(node->op());
+  if (type == MachineType::Int8()) {
+    opcode = kAtomicExchangeInt8;
+  } else if (type == MachineType::Uint8()) {
+    opcode = kAtomicExchangeUint8;
+  } else if (type == MachineType::Int16()) {
+    opcode = kAtomicExchangeInt16;
+  } else if (type == MachineType::Uint16()) {
+    opcode = kAtomicExchangeUint16;
+  } else if (type == MachineType::Int32() || type == MachineType::Uint32()) {
+    opcode = kAtomicExchangeWord32;
+  } else {
+    UNREACHABLE();
+    return;
+  }
+
+  AddressingMode addressing_mode = kMode_Offset_RR;
+  InstructionOperand inputs[3];
+  size_t input_count = 0;
+  inputs[input_count++] = g.UseUniqueRegister(base);
+  inputs[input_count++] = g.UseUniqueRegister(index);
+  inputs[input_count++] = g.UseUniqueRegister(value);
+  InstructionOperand outputs[1];
+  outputs[0] = g.UseUniqueRegister(node);
+  InstructionOperand temp[1];
+  temp[0] = g.TempRegister();
+  InstructionCode code = opcode | AddressingModeField::encode(addressing_mode);
+  Emit(code, 1, outputs, input_count, inputs, 1, temp);
+}
+
 #define SIMD_TYPE_LIST(V) \
   V(Float32x4)            \
   V(Int32x4)              \