[Atomics] Make Atomics.exchange a builtin using TF

src/builtins/builtins-sharedarraybuffer.cc

Index: src/builtins/builtins-sharedarraybuffer.cc
diff --git a/src/builtins/builtins-sharedarraybuffer.cc b/src/builtins/builtins-sharedarraybuffer.cc
index b91807833f78ebb4a300bb73f4df9e93997283cc..5a7b41bb6bb844cc1d62a67059e4ac7ffa045efe 100644
--- a/src/builtins/builtins-sharedarraybuffer.cc
+++ b/src/builtins/builtins-sharedarraybuffer.cc
@@ -266,5 +266,233 @@ void Builtins::Generate_AtomicsStore(compiler::CodeAssemblerState* state) {
   a.Return(a.SmiConstant(0));
 }
 
+#if V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64
+// The helper functions are duplicated from runtime-atomics.cc
+template <typename T>
+T FromObject(Handle<Object> number);
+
+template <>
+inline uint8_t FromObject<uint8_t>(Handle<Object> number) {
+  return NumberToUint32(*number);
+}
+
+template <>
+inline int8_t FromObject<int8_t>(Handle<Object> number) {
+  return NumberToInt32(*number);
+}
+
+template <>
+inline uint16_t FromObject<uint16_t>(Handle<Object> number) {
+  return NumberToUint32(*number);
+}
+
+template <>
+inline int16_t FromObject<int16_t>(Handle<Object> number) {
+  return NumberToInt32(*number);
+}
+
+template <>
+inline uint32_t FromObject<uint32_t>(Handle<Object> number) {
+  return NumberToUint32(*number);
+}
+
+template <>
+inline int32_t FromObject<int32_t>(Handle<Object> number) {
+  return NumberToInt32(*number);
+}
+
+inline Object* ToObject(Isolate* isolate, int8_t t) { return Smi::FromInt(t); }
+
+inline Object* ToObject(Isolate* isolate, uint8_t t) { return Smi::FromInt(t); }
+
+inline Object* ToObject(Isolate* isolate, int16_t t) { return Smi::FromInt(t); }
+
+inline Object* ToObject(Isolate* isolate, uint16_t t) {
+  return Smi::FromInt(t);
+}
+
+inline Object* ToObject(Isolate* isolate, int32_t t) {
+  return *isolate->factory()->NewNumber(t);
+}
+
+inline Object* ToObject(Isolate* isolate, uint32_t t) {
+  return *isolate->factory()->NewNumber(t);
+}
+
+template <typename T>
+inline T ExchangeSeqCst(T* p, T value) {
+  return __atomic_exchange_n(p, value, __ATOMIC_SEQ_CST);
+}
+
+template <typename T>
+inline Object* DoExchange(Isolate* isolate, void* buffer, size_t index,
+                          Handle<Object> obj) {
+  T value = FromObject<T>(obj);
+  T result = ExchangeSeqCst(static_cast<T*>(buffer) + index, value);
+  return ToObject(isolate, result);
+}
+
+// ES #sec-validatesharedintegertypedarray
+MUST_USE_RESULT MaybeHandle<JSTypedArray> ValidateSharedIntegerTypedArray(
+    Isolate* isolate, Handle<Object> object, bool only_int32 = false) {
+  if (object->IsJSTypedArray()) {
+    Handle<JSTypedArray> typedArray = Handle<JSTypedArray>::cast(object);
+    if (typedArray->GetBuffer()->is_shared()) {
+      if (only_int32) {
+        if (typedArray->type() == kExternalInt32Array) return typedArray;
+      } else {
+        if (typedArray->type() != kExternalFloat32Array &&
+            typedArray->type() != kExternalFloat64Array &&
+            typedArray->type() != kExternalUint8ClampedArray)
+          return typedArray;
+      }
+    }
+  }
+
+  THROW_NEW_ERROR(
+      isolate,
+      NewTypeError(only_int32 ? MessageTemplate::kNotInt32SharedTypedArray
+                              : MessageTemplate::kNotIntegerSharedTypedArray,
+                   object),
+      JSTypedArray);
+}
+
+// ES #sec-validateatomicaccess
+MUST_USE_RESULT Maybe<size_t> ValidateAtomicAccess(
+    Isolate* isolate, Handle<JSTypedArray> typedArray,
+    Handle<Object> requestIndex) {
+  // TOOD(v8:5961): Use ToIndex for indexes
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate, requestIndex, Object::ToNumber(requestIndex), Nothing<size_t>());
+  Handle<Object> offset;
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate, offset,
+                                   Object::ToInteger(isolate, requestIndex),
+                                   Nothing<size_t>());
+  if (!requestIndex->SameValue(*offset)) {
+    isolate->Throw(*isolate->factory()->NewRangeError(
+        MessageTemplate::kInvalidAtomicAccessIndex));
+    return Nothing<size_t>();
+  }
+  size_t accessIndex;
+  uint32_t length = typedArray->length_value();
+  if (!TryNumberToSize(*requestIndex, &accessIndex) || accessIndex >= length) {
+    isolate->Throw(*isolate->factory()->NewRangeError(
+        MessageTemplate::kInvalidAtomicAccessIndex));
+    return Nothing<size_t>();
+  }
+  return Just<size_t>(accessIndex);
+}
+
+#define INTEGER_TYPED_ARRAYS(V)          \
+  V(Uint8, uint8, UINT8, uint8_t, 1)     \
+  V(Int8, int8, INT8, int8_t, 1)         \
+  V(Uint16, uint16, UINT16, uint16_t, 2) \
+  V(Int16, int16, INT16, int16_t, 2)     \
+  V(Uint32, uint32, UINT32, uint32_t, 4) \
+  V(Int32, int32, INT32, int32_t, 4)
+
+BUILTIN(AtomicsExchange) {
+  HandleScope scope(isolate);
+  Handle<Object> array = args.atOrUndefined(isolate, 1);
+  Handle<Object> index = args.atOrUndefined(isolate, 2);
+  Handle<Object> value = args.atOrUndefined(isolate, 3);
+
+  Handle<JSTypedArray> sta;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, sta, ValidateSharedIntegerTypedArray(isolate, array));
+
+  Maybe<size_t> maybeIndex = ValidateAtomicAccess(isolate, sta, index);
+  if (maybeIndex.IsNothing()) return isolate->heap()->exception();
+  size_t i = maybeIndex.FromJust();
+
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, value,
+                                     Object::ToInteger(isolate, value));
+
+  uint8_t* source = static_cast<uint8_t*>(sta->GetBuffer()->backing_store()) +
+                    NumberToSize(sta->byte_offset());
+
+  switch (sta->type()) {
+#define TYPED_ARRAY_CASE(Type, typeName, TYPE, ctype, size) \
+  case kExternal##Type##Array:                              \
+    return DoExchange<ctype>(isolate, source, i, value);
+
+    INTEGER_TYPED_ARRAYS(TYPED_ARRAY_CASE)
+#undef TYPED_ARRAY_CASE
+
+    default:
+      break;
+  }
+
+  UNREACHABLE();
+  return isolate->heap()->undefined_value();
+}
+#else
+void Builtins::Generate_AtomicsExchange(compiler::CodeAssemblerState* state) {
+  using compiler::Node;
+  CodeStubAssembler a(state);
+  Node* array = a.Parameter(1);
+  Node* index = a.Parameter(2);
+  Node* value = a.Parameter(3);
+  Node* context = a.Parameter(4 + 2);
+
+  Node* instance_type;
+  Node* backing_store;
+  ValidateSharedTypedArray(&a, array, context, &instance_type, &backing_store);
+
+  Node* index_word32 = ConvertTaggedAtomicIndexToWord32(&a, index, context);
+  Node* array_length_word32 = a.TruncateTaggedToWord32(
+      context, a.LoadObjectField(array, JSTypedArray::kLengthOffset));
+  ValidateAtomicIndex(&a, index_word32, array_length_word32, context);
+  Node* index_word = a.ChangeUint32ToWord(index_word32);
+
+  Node* value_integer = a.ToInteger(context, value);
+  Node* value_word32 = a.TruncateTaggedToWord32(context, value_integer);
+
+  CodeStubAssembler::Label i8(&a), u8(&a), i16(&a), u16(&a), i32(&a), u32(&a),
+      other(&a);
+  int32_t case_values[] = {
+      FIXED_INT8_ARRAY_TYPE,   FIXED_UINT8_ARRAY_TYPE, FIXED_INT16_ARRAY_TYPE,
+      FIXED_UINT16_ARRAY_TYPE, FIXED_INT32_ARRAY_TYPE, FIXED_UINT32_ARRAY_TYPE,
+  };
+  CodeStubAssembler::Label* case_labels[] = {
+      &i8, &u8, &i16, &u16, &i32, &u32,
+  };
+  a.Switch(instance_type, &other, case_values, case_labels,
+           arraysize(case_labels));
+
+  a.Bind(&i8);
+  a.Return(a.SmiFromWord32(a.AtomicExchange(MachineType::Int8(), backing_store,
+                                            index_word, value_word32)));
+
+  a.Bind(&u8);
+  a.Return(a.SmiFromWord32(a.AtomicExchange(MachineType::Uint8(), backing_store,
+                                            index_word, value_word32)));
+
+  a.Bind(&i16);
+  a.Return(a.SmiFromWord32(a.AtomicExchange(MachineType::Int16(), backing_store,
+                                            a.WordShl(index_word, 1),
+                                            value_word32)));
+
+  a.Bind(&u16);
+  a.Return(a.SmiFromWord32(
+      a.AtomicExchange(MachineType::Uint16(), backing_store,
+                       a.WordShl(index_word, 1), value_word32)));
+
+  a.Bind(&i32);
+  a.Return(a.ChangeInt32ToTagged(
+      a.AtomicExchange(MachineType::Int32(), backing_store,
+                       a.WordShl(index_word, 2), value_word32)));
+
+  a.Bind(&u32);
+  a.Return(a.ChangeUint32ToTagged(
+      a.AtomicExchange(MachineType::Uint32(), backing_store,
+                       a.WordShl(index_word, 2), value_word32)));
+
+  // This shouldn't happen, we've already validated the type.
+  a.Bind(&other);
+  a.Return(a.SmiConstant(0));
+}
+#endif  // V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64
+
 }  // namespace internal
 }  // namespace v8