[Atomics] Remove Atomics code stubs; use TF ops

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index d054916db0a700e330ea3aac6abf859d0ec4226a..835445d95585d835e66b55bad6537186c5edae2c 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -5148,7 +5148,9 @@ void Builtins::Generate_StackCheck(MacroAssembler* masm) {
 namespace {
 
 void ValidateSharedTypedArray(compiler::CodeStubAssembler* a,
-                              compiler::Node* tagged, compiler::Node* context) {
+                              compiler::Node* tagged, compiler::Node* context,
+                              compiler::Node** out_instance_type,
+                              compiler::Node** out_backing_store) {
   using namespace compiler;
   CodeStubAssembler::Label is_smi(a), not_smi(a), is_typed_array(a),
       not_typed_array(a), is_shared(a), not_shared(a), is_float_or_clamped(a),
@@ -5169,10 +5171,9 @@ void ValidateSharedTypedArray(compiler::CodeStubAssembler* a,
 
   // Fail if the array's JSArrayBuffer is not shared.
   a->Bind(&is_typed_array);
-  Node* is_buffer_shared =
-      a->BitFieldDecode<JSArrayBuffer::IsShared>(a->LoadObjectField(
-          a->LoadObjectField(tagged, JSTypedArray::kBufferOffset),
-          JSArrayBuffer::kBitFieldOffset));
+  Node* array_buffer = a->LoadObjectField(tagged, JSTypedArray::kBufferOffset);
+  Node* is_buffer_shared = a->BitFieldDecode<JSArrayBuffer::IsShared>(
+      a->LoadObjectField(array_buffer, JSArrayBuffer::kBitFieldOffset));
   a->Branch(is_buffer_shared, &is_shared, &not_shared);
   a->Bind(&not_shared);
   a->Goto(&invalid);
@@ -5199,6 +5200,14 @@ void ValidateSharedTypedArray(compiler::CodeStubAssembler* a,
   a->Return(a->UndefinedConstant());
 
   a->Bind(&not_float_or_clamped);
+  *out_instance_type = elements_instance_type;
+
+  Node* backing_store =
+      a->LoadObjectField(array_buffer, JSArrayBuffer::kBackingStoreOffset);
+  Node* byte_offset = a->ChangeUint32ToWord(a->TruncateTaggedToWord32(
+      context,
+      a->LoadObjectField(tagged, JSArrayBufferView::kByteOffsetOffset)));
+  *out_backing_store = a->IntPtrAdd(backing_store, byte_offset);
 }
 
 // https://tc39.github.io/ecmascript_sharedmem/shmem.html#Atomics.ValidateAtomicAccess
@@ -5265,22 +5274,61 @@ void ValidateAtomicIndex(compiler::CodeStubAssembler* a,
 
 }  // anonymous namespace
 
-void Builtins::Generate_AtomicsLoadCheck(compiler::CodeStubAssembler* a) {
+void Builtins::Generate_AtomicsLoad(compiler::CodeStubAssembler* a) {
   using namespace compiler;
-  Isolate* isolate = a->isolate();
   Node* array = a->Parameter(1);
   Node* index = a->Parameter(2);
   Node* context = a->Parameter(3 + 2);
-  ValidateSharedTypedArray(a, array, context);
-  Node* index_word = ConvertTaggedAtomicIndexToWord32(a, index, context);
-  Node* array_length_word = a->TruncateTaggedToWord32(
+
+  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_word, array_length_word, context);
+  ValidateAtomicIndex(a, index_word32, array_length_word32, context);
+  Node* index_word = a->ChangeUint32ToWord(index_word32);
+
+  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->SmiTag(a->AtomicLoad(MachineType::Int8(), backing_store, index_word)));
+
+  a->Bind(&u8);
+  a->Return(a->SmiTag(
+      a->AtomicLoad(MachineType::Uint8(), backing_store, index_word)));
+
+  a->Bind(&i16);
+  a->Return(a->SmiTag(a->AtomicLoad(MachineType::Int16(), backing_store,
+                                    a->WordShl(index_word, 1))));
+
+  a->Bind(&u16);
+  a->Return(a->SmiTag(a->AtomicLoad(MachineType::Uint16(), backing_store,
+                                    a->WordShl(index_word, 1))));
+
+  a->Bind(&i32);
+  a->Return(a->ChangeInt32ToTagged(a->AtomicLoad(
+      MachineType::Int32(), backing_store, a->WordShl(index_word, 2))));
+
+  a->Bind(&u32);
+  a->Return(a->ChangeUint32ToTagged(a->AtomicLoad(
+      MachineType::Uint32(), backing_store, a->WordShl(index_word, 2))));
 
-  Callable atomics_load = CodeFactory::AtomicsLoad(isolate);
-  Node* target = a->HeapConstant(atomics_load.code());
-  a->Return(a->CallStub(atomics_load.descriptor(), target, context, array,
-                        index_word));
+  // This shouldn't happen, we've already validated the type.
+  a->Bind(&other);
+  a->Return(a->Int32Constant(0));
 }
 
 #define DEFINE_BUILTIN_ACCESSOR_C(name, ignore)               \