In-heap small typed arrays

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6448 matching lines @@
     HCompareMap* mapcompare =
         New<HCompareMap>(object, map, this_map, other_map);
     FinishCurrentBlock(mapcompare);
 
     set_current_block(this_map);
     HInstruction* access = NULL;
     if (IsDictionaryElementsKind(elements_kind)) {
       access = AddInstruction(BuildKeyedGeneric(access_type, object, key, val));
     } else {
       ASSERT(IsFastElementsKind(elements_kind) ||
-             IsExternalArrayElementsKind(elements_kind));
+             IsExternalArrayElementsKind(elements_kind) ||
+             IsFixedTypedArrayElementsKind(elements_kind));
       LoadKeyedHoleMode load_mode = BuildKeyedHoleMode(map);
       // Happily, mapcompare is a checked object.
       access = BuildUncheckedMonomorphicElementAccess(
           mapcompare, key, val,
           map->instance_type() == JS_ARRAY_TYPE,
           elements_kind, access_type,
           load_mode,
           store_mode);
     }
     *has_side_effects |= access->HasObservableSideEffects();
@@ skipping 1931 matching lines @@
   for (int offset = ViewClass::kSize;
        offset < ViewClass::kSizeWithInternalFields;
        offset += kPointerSize) {
     Add<HStoreNamedField>(obj,
         HObjectAccess::ForObservableJSObjectOffset(offset),
         graph()->GetConstant0());
   }
 
   Add<HStoreNamedField>(
       obj,
-      HObjectAccess::ForJSArrayBufferViewBuffer(), buffer);
-  Add<HStoreNamedField>(
-      obj,
       HObjectAccess::ForJSArrayBufferViewByteOffset(),
       byte_offset);
   Add<HStoreNamedField>(
       obj,
       HObjectAccess::ForJSArrayBufferViewByteLength(),
       byte_length);
 
-  HObjectAccess weak_first_view_access =
-      HObjectAccess::ForJSArrayBufferWeakFirstView();
-  Add<HStoreNamedField>(obj,
-      HObjectAccess::ForJSArrayBufferViewWeakNext(),
-      Add<HLoadNamedField>(buffer, static_cast<HValue*>(NULL),
-                           weak_first_view_access));
-  Add<HStoreNamedField>(
-      buffer, weak_first_view_access, obj);
+  if (buffer != NULL) {
+    Add<HStoreNamedField>(
+        obj,
+        HObjectAccess::ForJSArrayBufferViewBuffer(), buffer);
+    HObjectAccess weak_first_view_access =
+        HObjectAccess::ForJSArrayBufferWeakFirstView();
+    Add<HStoreNamedField>(obj,
+        HObjectAccess::ForJSArrayBufferViewWeakNext(),
+        Add<HLoadNamedField>(buffer,
+                             static_cast<HValue*>(NULL),
+                             weak_first_view_access));
+    Add<HStoreNamedField>(buffer, weak_first_view_access, obj);
+  } else {
+    Add<HStoreNamedField>(
+        obj,
+        HObjectAccess::ForJSArrayBufferViewBuffer(),
+        Add<HConstant>(static_cast<int32_t>(0)));
+    Add<HStoreNamedField>(obj,
+        HObjectAccess::ForJSArrayBufferViewWeakNext(),
+        graph()->GetConstantUndefined());
+  }
 }
 
 
 void HOptimizedGraphBuilder::VisitDataViewInitialize(
     CallRuntime* expr) {
   ZoneList<Expression*>* arguments = expr->arguments();
 
   NoObservableSideEffectsScope scope(this);
   ASSERT(arguments->length()== 4);
   CHECK_ALIVE(VisitForValue(arguments->at(0)));
   HValue* obj = Pop();
 
   CHECK_ALIVE(VisitForValue(arguments->at(1)));
   HValue* buffer = Pop();
 
   CHECK_ALIVE(VisitForValue(arguments->at(2)));
   HValue* byte_offset = Pop();
 
   CHECK_ALIVE(VisitForValue(arguments->at(3)));
   HValue* byte_length = Pop();
 
   BuildArrayBufferViewInitialization<JSDataView>(
       obj, buffer, byte_offset, byte_length);
 }
 
 
-void HOptimizedGraphBuilder::VisitTypedArrayInitialize(
-    CallRuntime* expr) {
+static Handle<Map> TypedArrayMap(Isolate* isolate,
+                                 ExternalArrayType array_type,
+                                 ElementsKind target_kind) {
+  Handle<Context> native_context = isolate->native_context();
+  Handle<JSFunction> fun;
+  switch (array_type) {
+#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size)                       \
+    case kExternal##Type##Array:                                              \
+      fun = Handle<JSFunction>(native_context->type##_array_fun());           \
+      break;
+
+    TYPED_ARRAYS(TYPED_ARRAY_CASE)
+#undef TYPED_ARRAY_CASE
+  }
+  Handle<Map> map(fun->initial_map());
+  return Map::AsElementsKind(map, target_kind);
+}
+
+
+void HOptimizedGraphBuilder::VisitTypedArrayInitialize(CallRuntime* expr) {
   ZoneList<Expression*>* arguments = expr->arguments();
 
   NoObservableSideEffectsScope scope(this);
   static const int kObjectArg = 0;
   static const int kArrayIdArg = 1;
   static const int kBufferArg = 2;
   static const int kByteOffsetArg = 3;
   static const int kByteLengthArg = 4;
   static const int kArgsLength = 5;
   ASSERT(arguments->length() == kArgsLength);
 
 
   CHECK_ALIVE(VisitForValue(arguments->at(kObjectArg)));
   HValue* obj = Pop();
 
   ASSERT(arguments->at(kArrayIdArg)->node_type() == AstNode::kLiteral);
   Handle<Object> value =
       static_cast<Literal*>(arguments->at(kArrayIdArg))->value();
   ASSERT(value->IsSmi());
   int array_id = Smi::cast(*value)->value();
 
-  CHECK_ALIVE(VisitForValue(arguments->at(kBufferArg)));
-  HValue* buffer = Pop();
+  HValue* buffer;
+  if (!arguments->at(kBufferArg)->IsNullLiteral()) {
+    CHECK_ALIVE(VisitForValue(arguments->at(kBufferArg)));
+    buffer = Pop();
+  } else {
+    buffer = NULL;
+  }
 
   HValue* byte_offset;
   bool is_zero_byte_offset;
 
   if (arguments->at(kByteOffsetArg)->node_type() == AstNode::kLiteral
       && Smi::FromInt(0) ==
       *static_cast<Literal*>(arguments->at(kByteOffsetArg))->value()) {
     byte_offset = Add<HConstant>(static_cast<int32_t>(0));
     is_zero_byte_offset = true;
   } else {
     CHECK_ALIVE(VisitForValue(arguments->at(kByteOffsetArg)));
     byte_offset = Pop();
     is_zero_byte_offset = false;
+    ASSERT(buffer != NULL);
   }
 
   CHECK_ALIVE(VisitForValue(arguments->at(kByteLengthArg)));
   HValue* byte_length = Pop();
 
   IfBuilder byte_offset_smi(this);
 
   if (!is_zero_byte_offset) {
     byte_offset_smi.If<HIsSmiAndBranch>(byte_offset);
     byte_offset_smi.Then();
   }
 
+  ExternalArrayType array_type =
+      kExternalInt8Array;  // Bogus initialization.
+  size_t element_size = 1;  // Bogus initialization.
+  ElementsKind external_elements_kind =  // Bogus initialization.
+      EXTERNAL_INT8_ELEMENTS;
+  ElementsKind fixed_elements_kind =  // Bogus initialization.
+      INT8_ELEMENTS;
+  Runtime::ArrayIdToTypeAndSize(array_id,
+      &array_type,
+      &external_elements_kind,
+      &fixed_elements_kind,
+      &element_size);
+
+
   { //  byte_offset is Smi.
     BuildArrayBufferViewInitialization<JSTypedArray>(
         obj, buffer, byte_offset, byte_length);
 
-    ExternalArrayType array_type = kExternalInt8Array;  // Bogus initialization.
-    size_t element_size = 1;  // Bogus initialization.
-    Runtime::ArrayIdToTypeAndSize(array_id, &array_type, &element_size);
 
     HInstruction* length = AddUncasted<HDiv>(byte_length,
         Add<HConstant>(static_cast<int32_t>(element_size)));
 
     Add<HStoreNamedField>(obj,
         HObjectAccess::ForJSTypedArrayLength(),
         length);
 
-    Handle<Map> external_array_map(
-        isolate()->heap()->MapForExternalArrayType(array_type));
+    HValue* elements;
+    if (buffer != NULL) {
+      Handle<Map> external_array_map(
+          isolate()->heap()->MapForExternalArrayType(array_type));
+      elements =
+          Add<HAllocate>(
+              Add<HConstant>(ExternalArray::kAlignedSize),
+              HType::JSArray(),

[Toon Verwaest, 2014/03/24 11:16:12]

Is this correct? I'd think only obj is HType::JSArray(), not the elements.

[Dmitry Lomov (no reviews), 2014/03/25 10:17:40]

Done.

+              NOT_TENURED,
+              external_array_map->instance_type());
 
-    HValue* elements =
-        Add<HAllocate>(
-            Add<HConstant>(ExternalArray::kAlignedSize),
-            HType::JSArray(),
-            NOT_TENURED,
-            external_array_map->instance_type());
+      AddStoreMapConstant(elements, external_array_map);
 
-    AddStoreMapConstant(elements, external_array_map);
+      HValue* backing_store = Add<HLoadNamedField>(
+          buffer, static_cast<HValue*>(NULL),
+          HObjectAccess::ForJSArrayBufferBackingStore());
 
-    HValue* backing_store = Add<HLoadNamedField>(
-        buffer, static_cast<HValue*>(NULL),
-        HObjectAccess::ForJSArrayBufferBackingStore());
+      HValue* typed_array_start;
+      if (is_zero_byte_offset) {
+        typed_array_start = backing_store;
+      } else {
+        HInstruction* external_pointer =
+            AddUncasted<HAdd>(backing_store, byte_offset);
+        // Arguments are checked prior to call to TypedArrayInitialize,
+        // including byte_offset.
+        external_pointer->ClearFlag(HValue::kCanOverflow);
+        typed_array_start = external_pointer;
+      }
 
-    HValue* typed_array_start;
-    if (is_zero_byte_offset) {
-      typed_array_start = backing_store;
+
+      Add<HStoreNamedField>(elements,
+          HObjectAccess::ForExternalArrayExternalPointer(),
+          typed_array_start);
+
+      Handle<Map> obj_map = TypedArrayMap(
+          isolate(), array_type, external_elements_kind);
+      AddStoreMapConstant(obj, obj_map);
+      Add<HStoreNamedField>(elements,
+          HObjectAccess::ForFixedArrayLength(),
+          length, INITIALIZING_STORE);
     } else {
-      HInstruction* external_pointer =
-          AddUncasted<HAdd>(backing_store, byte_offset);
-      // Arguments are checked prior to call to TypedArrayInitialize,
-      // including byte_offset.
-      external_pointer->ClearFlag(HValue::kCanOverflow);
-      typed_array_start = external_pointer;
+      ASSERT(is_zero_byte_offset);
+
+      STATIC_ASSERT(
+          (FixedTypedArrayBase::kHeaderSize & kObjectAlignmentMask) == 0);
+      HValue* total_size;
+
+      // if fixed array's elements are not aligned to object's alignment,
+      // we need to align the whole array to object alignment.
+      if (element_size % kObjectAlignment != 0) {
+        HConstant* header_size = Add<HConstant>(static_cast<int32_t>(
+              FixedTypedArrayBase::kHeaderSize + kObjectAlignmentMask));
+        HValue* unaligned_size = AddUncasted<HAdd>(byte_length, header_size);
+        unaligned_size->ClearFlag(HValue::kCanOverflow);
+        total_size = AddUncasted<HBitwise>(
+            Token::BIT_AND, unaligned_size,
+            Add<HConstant>(static_cast<int32_t>(~kObjectAlignmentMask)));
+      } else {
+        total_size = AddUncasted<HAdd>(byte_length,
+            Add<HConstant>(FixedTypedArrayBase::kHeaderSize));
+        total_size->ClearFlag(HValue::kCanOverflow);

[Toon Verwaest, 2014/03/24 11:16:12]

Is this the only place where we do alignment? If not, can we join that code into
an alignment helper function?

[Dmitry Lomov (no reviews), 2014/03/25 10:17:40]

Done.

+      }
+
+      Handle<Map> fixed_typed_array_map(
+          isolate()->heap()->MapForFixedTypedArray(array_type));
+      elements =
+          Add<HAllocate>(total_size, HType::JSArray(),

[Toon Verwaest, 2014/03/24 11:16:12]

Not a JSArray()

[Dmitry Lomov (no reviews), 2014/03/25 10:17:40]

Done.

+              NOT_TENURED,
+              fixed_typed_array_map->instance_type());
+      AddStoreMapConstant(elements, fixed_typed_array_map);
+
+      Add<HStoreNamedField>(elements,
+          HObjectAccess::ForFixedArrayLength(),
+          length, INITIALIZING_STORE);
+      HValue* filler = Add<HConstant>(static_cast<int32_t>(0));
+
+      {
+        LoopBuilder builder(this, context(), LoopBuilder::kPostIncrement);
+
+        HValue* key = builder.BeginBody(
+            Add<HConstant>(static_cast<int32_t>(0)),
+            length, Token::LT);
+        Add<HStoreKeyed>(elements, key, filler, fixed_elements_kind);
+
+        builder.EndBody();
+      }
     }
-
-    Add<HStoreNamedField>(elements,
-        HObjectAccess::ForExternalArrayExternalPointer(),
-        typed_array_start);
-    Add<HStoreNamedField>(elements,
-        HObjectAccess::ForFixedArrayLength(),
-        length);
+    Add<HStoreNamedField>(
+        elements, HObjectAccess::ForFixedArrayLength(), length,
+        INITIALIZING_STORE);
     Add<HStoreNamedField>(
         obj, HObjectAccess::ForElementsPointer(), elements);
   }
 
   if (!is_zero_byte_offset) {
     byte_offset_smi.Else();
     { //  byte_offset is not Smi.
       Push(obj);
       CHECK_ALIVE(VisitForValue(arguments->at(kArrayIdArg)));
       Push(buffer);
@@ skipping 25 matching lines @@
   if (function->function_id == Runtime::kTypedArrayInitialize) {
     return VisitTypedArrayInitialize(expr);
   }
 
   if (function->function_id == Runtime::kMaxSmi) {
     ASSERT(expr->arguments()->length() == 0);
     HConstant* max_smi = New<HConstant>(static_cast<int32_t>(Smi::kMaxValue));
     return ast_context()->ReturnInstruction(max_smi, expr->id());
   }
 
+
+  if (function->function_id == Runtime::kTypedArrayMaxSizeInHeap) {
+    ASSERT(expr->arguments()->length() == 0);
+    HConstant* value = New<HConstant>(
+        static_cast<int32_t>(FLAG_typed_array_max_size_in_heap));
+    return ast_context()->ReturnInstruction(value, expr->id());
+  }
+
   if (function->intrinsic_type == Runtime::INLINE) {
     ASSERT(expr->name()->length() > 0);
     ASSERT(expr->name()->Get(0) == '_');
     // Call to an inline function.
     int lookup_index = static_cast<int>(function->function_id) -
         static_cast<int>(Runtime::kFirstInlineFunction);
     ASSERT(lookup_index >= 0);
     ASSERT(static_cast<size_t>(lookup_index) <
            ARRAY_SIZE(kInlineFunctionGenerators));
     InlineFunctionGenerator generator = kInlineFunctionGenerators[lookup_index];
@@ skipping 2692 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal