Hydrogen stubs for array constructors

src/hydrogen.cc

 // Copyright 2012 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 1311 matching lines @@
   store_map->SetGVNFlag(kChangesMaps);
   AddInstruction(store_map);
   return store_map;
 }
 
 
 HInstruction* HGraphBuilder::BuildStoreMap(HValue* object,
                                            Handle<Map> map,
                                            BailoutId id) {
   Zone* zone = this->zone();
-  HValue* map_constant =
-      AddInstruction(new(zone) HConstant(map, Representation::Tagged()));
+  HConstant* map_constant = new(zone) HConstant(map, Representation::Tagged());
+  AddInstruction(map_constant);
   return BuildStoreMap(object, map_constant, id);
 }
 
 
 HValue* HGraphBuilder::BuildNewElementsCapacity(HValue* context,
                                                 HValue* old_capacity) {
   Zone* zone = this->zone();
   HValue* half_old_capacity =
       AddInstruction(HShr::New(zone, context, old_capacity,
                                graph_->GetConstant1()));
@@ skipping 239 matching lines @@
                                            key_constant,
                                            value,
                                            kind));
     }
   }
 
   return object;
 }
 
 
+HGraphBuilder::JSArrayBuilder::JSArrayBuilder(HGraphBuilder* builder,
+                                              ElementsKind kind,
+                                              HValue* allocation_site_payload) :
+        builder_(builder),
+        kind_(kind),
+        allocation_site_payload_(allocation_site_payload) {
+  // Determine mode
+  mode_ = AllocationSiteInfo::GetMode(kind);
+}
+
+
+HValue* HGraphBuilder::JSArrayBuilder::EmitMapCode(HValue* context) {
+  // Get the global context, the native context, the map array
+  HInstruction* global_object = AddInstruction(new(zone())
+      HGlobalObject(context));
+  HInstruction* native_context = AddInstruction(new(zone())
+      HLoadNamedField(global_object, true, GlobalObject::kNativeContextOffset));
+  size_t offset = Context::kHeaderSize +
+      kPointerSize * Context::JS_ARRAY_MAPS_INDEX;
+  HInstruction* map_array = AddInstruction(new(zone())
+      HLoadNamedField(native_context, true, offset));
+  offset = kind_ * kPointerSize + FixedArrayBase::kHeaderSize;
+  return AddInstruction(new(zone()) HLoadNamedField(map_array, true, offset));
+}
+
+
+HValue* HGraphBuilder::JSArrayBuilder::EstablishAllocationSize(
+    HValue* length_node) {
+  HValue* context = builder()->environment()->LookupContext();
+  ASSERT(length_node != NULL);
+
+  int base_size = JSArray::kSize;
+  if (mode_ == TRACK_ALLOCATION_SITE) {
+    base_size += AllocationSiteInfo::kSize;
+  }
+
+  if (IsFastDoubleElementsKind(kind_)) {
+    base_size += FixedDoubleArray::kHeaderSize;
+  } else {
+    base_size += FixedArray::kHeaderSize;
+  }
+
+  HInstruction* elements_size_value = new(zone())
+      HConstant(elements_size(), Representation::Integer32());
+  AddInstruction(elements_size_value);
+  HInstruction* mul = HMul::New(zone(), context, length_node,
+                                elements_size_value);
+  mul->ChangeRepresentation(Representation::Integer32());
+  mul->ClearFlag(HValue::kCanOverflow);
+  AddInstruction(mul);
+  AddSimulate();
+
+  HInstruction* base = new(zone()) HConstant(base_size,
+                                             Representation::Integer32());
+  AddInstruction(base);
+  HInstruction* total_size = HAdd::New(zone(), context, base, mul);
+  total_size->ChangeRepresentation(Representation::Integer32());
+  total_size->ClearFlag(HValue::kCanOverflow);
+  AddInstruction(total_size);
+  AddSimulate();
+  return total_size;
+}
+
+
+HValue* HGraphBuilder::JSArrayBuilder::EstablishEmptyArrayAllocationSize() {
+  int base_size = JSArray::kSize;
+  if (mode_ == TRACK_ALLOCATION_SITE) {
+    base_size += AllocationSiteInfo::kSize;
+  }
+
+  if (initial_capacity() > 0) {
+    base_size += IsFastDoubleElementsKind(kind_)
+        ? FixedDoubleArray::SizeFor(initial_capacity())
+        : FixedArray::SizeFor(initial_capacity());
+  }
+
+  HConstant* array_size =
+      new(zone()) HConstant(base_size, Representation::Integer32());
+  AddInstruction(array_size);
+  return array_size;
+}
+
+
+HValue* HGraphBuilder::JSArrayBuilder::AllocateEmptyArray() {
+  HValue* size_in_bytes = EstablishEmptyArrayAllocationSize();
+  HConstant* capacity =
+      new(zone()) HConstant(initial_capacity(), Representation::Integer32());
+  AddInstruction(capacity);
+  return AllocateArray(size_in_bytes, capacity, NULL, true);
+}
+
+
+HValue* HGraphBuilder::JSArrayBuilder::AllocateArray(HValue* size_in_bytes,
+                                                     HValue* capacity,
+                                                     HValue* length_field,
+                                                     bool fill_with_hole) {
+  HValue* context = builder()->environment()->LookupContext();
+  Isolate* isolate = builder()->graph()->isolate();

[mvstanton, 2013/04/15 15:14:49]

Hannes: How about for symmetry with BuildCopyObjectHeader, have a
BuildObjectHeader that deals with the header portion of the array we are
creating.

[mvstanton, 2013/04/16 11:48:52]

Done. And I continued in this spirit, finding several more refactorings that
allowed sharing with other recently created "Builder" code.

+
+  // Allocate (dealing with failure appropriately)
+  HAllocate::Flags flags = HAllocate::CAN_ALLOCATE_IN_NEW_SPACE;
+  if (IsFastDoubleElementsKind(kind_)) {
+    flags = static_cast<HAllocate::Flags>(
+        flags | HAllocate::ALLOCATE_DOUBLE_ALIGNED);
+  }
+
+  HAllocate* new_object = new(zone()) HAllocate(context, size_in_bytes,

[mvstanton, 2013/04/15 15:14:49]

Hannes: How about if HAllocate deals with the ALLOCATE_DOUBLE_ALIGNED_FLAG?)

[mvstanton, 2013/04/16 11:48:52]

I made a useful helper function to improve this. It still seemed difficult and
outside of scope to completely hide flags inside the HAllocate class.

+                                                HType::JSArray(), flags);
+  AddInstruction(new_object);
+
+  // Fill in the fields: map, properties, length
+  HValue* map = EmitMapCode(context);
+  builder()->BuildStoreMap(new_object, map, BailoutId::StubEntry());
+
+  HConstant* empty_fixed_array =
+      new(zone()) HConstant(
+          Handle<FixedArray>(isolate->heap()->empty_fixed_array()),
+          Representation::Tagged());
+  AddInstruction(empty_fixed_array);
+
+  AddInstruction(new(zone()) HStoreNamedField(new_object,
+      isolate->factory()->properties_field_symbol(),
+      empty_fixed_array,
+      true,
+      JSArray::kPropertiesOffset));
+  AddSimulate(FIXED_SIMULATE);
+
+  HValue* zero = builder()->graph()->GetConstant0();
+  HValue* array_length_field = zero;
+  if (length_field != NULL) {
+    array_length_field = length_field;
+  }
+  AddInstruction(new(zone()) HStoreNamedField(new_object,
+      isolate->factory()->length_field_string(),
+      array_length_field,
+      true,
+      JSArray::kLengthOffset));
+  AddSimulate(FIXED_SIMULATE);
+
+  if (mode_ == TRACK_ALLOCATION_SITE) {

[mvstanton, 2013/04/15 15:14:49]

Hannes: Factor this out to combine with the piece of code in BuildEmitDeepCopy
that builds the AllocationSiteInfo object.

[mvstanton, 2013/04/16 11:48:52]

Done.

+    // Fill in the payload
+    HInnerAllocatedObject* allocation_info_site = new(zone())
+        HInnerAllocatedObject(new_object, JSArray::kSize);
+    AddInstruction(allocation_info_site);
+    builder()->BuildStoreMap(allocation_info_site,
+                  Handle<Map>(isolate->heap()->allocation_site_info_map()),
+                  BailoutId::StubEntry());
+    AddInstruction(new(zone()) HStoreNamedField(allocation_info_site,
+        isolate->factory()->payload_field_symbol(),
+        allocation_site_payload_,
+        true,
+        AllocationSiteInfo::kPayloadOffset));
+    AddSimulate(FIXED_SIMULATE);
+  }
+
+  if (length_field == NULL && initial_capacity() == 0) {
+    AddInstruction(new(zone()) HStoreNamedField(new_object,
+        isolate->factory()->elements_field_string(),
+        empty_fixed_array,
+        true,
+        JSArray::kElementsOffset));
+    AddSimulate(FIXED_SIMULATE);
+  } else {
+    int elements_location = JSArray::kSize;
+    if (mode_ == TRACK_ALLOCATION_SITE) {
+      elements_location += AllocationSiteInfo::kSize;
+    }
+
+    elements_location_ = new(zone()) HInnerAllocatedObject(new_object,
+                                                           elements_location);
+    AddInstruction(elements_location_);
+
+    AddInstruction(new(zone()) HStoreNamedField(new_object,
+        isolate->factory()->elements_field_string(),
+        elements_location_,
+        true,
+        JSArray::kElementsOffset));
+    AddSimulate(FIXED_SIMULATE);
+
+    // Initialize the elements
+    Handle<Map> map_elements = IsFastDoubleElementsKind(kind_)
+        ? isolate->factory()->fixed_double_array_map()
+        : isolate->factory()->fixed_array_map();
+    builder()->BuildStoreMap(elements_location_, map_elements,
+                             BailoutId::StubEntry());
+
+    Handle<String> fixed_array_length_field_name =
+        isolate->factory()->length_field_string();
+    HInstruction* store_length =
+        new(zone()) HStoreNamedField(elements_location_,
+                                     fixed_array_length_field_name,
+                                     capacity,
+                                     true,
+                                     FixedArray::kLengthOffset);
+    AddInstruction(store_length);
+    AddSimulate(FIXED_SIMULATE);
+
+    if (fill_with_hole) {
+      FillWithHole(capacity, length_field == NULL);
+    }
+  }
+
+  return new_object;
+}
+
+
+void HGraphBuilder::JSArrayBuilder::FillWithHole(HValue* capacity,
+                                                 bool nominally_empty) {
+  Isolate* isolate = builder()->graph()->isolate();
+  HValue* context = builder()->environment()->LookupContext();
+  double nan_double = FixedDoubleArray::hole_nan_as_double();
+  HConstant* hole = (IsFastSmiElementsKind(kind_) ||
+                  IsFastObjectElementsKind(kind_))

[mvstanton, 2013/04/15 15:14:49]

lines above replace with IsFastDoubleElementsKind(kind_). 

[mvstanton, 2013/04/16 11:48:52]

Done. Actually I could merge this function with another and remove it
completely.

+      ? new(zone()) HConstant(isolate->factory()->the_hole_value(),
+          Representation::Tagged())
+      : new(zone()) HConstant(nan_double, Representation::Double());
+
+  AddInstruction(hole);
+
+  static const int kLoopUnfoldLimit = 4;
+  if (nominally_empty && initial_capacity() <= kLoopUnfoldLimit) {

[mvstanton, 2013/04/15 15:14:49]

move kLoopUnfoldLimit up to initial_capacity() definition point (and coalesce
with builtins-ia32.cc version of kLoopUnfoldLimit.

+    for (int i = 0; i < initial_capacity(); i ++) {
+      HInstruction* key;
+      if (i == 0) {
+        key = graph()->GetConstant0();
+      } else if (i == 1) {
+        key = graph()->GetConstant1();
+      } else {
+        key = AddInstruction(new(zone())
+                             HConstant(i, Representation::Integer32()));
+      }
+      AddInstruction(new(zone()) HStoreKeyed(elements_location_, key, hole,
+                                             kind_));
+      AddSimulate(REMOVABLE_SIMULATE);
+    }
+  } else {
+    LoopBuilder loop_builder(builder(),
+                             context,
+                             LoopBuilder::kPostIncrement);
+    HValue* zero = graph()->GetConstant0();
+    HValue* start = zero;
+    HValue* key = loop_builder.BeginBody(start, capacity, Token::LT);
+
+    AddInstruction(new(zone()) HStoreKeyed(elements_location_, key, hole,
+                                           kind_));
+    AddSimulate(REMOVABLE_SIMULATE);
+    loop_builder.EndBody();
+  }
+}
+
+
 HOptimizedGraphBuilder::HOptimizedGraphBuilder(CompilationInfo* info,
                                                TypeFeedbackOracle* oracle)
     : HGraphBuilder(info),
       function_state_(NULL),
       initial_function_state_(this, info, oracle, NORMAL_RETURN),
       ast_context_(NULL),
       break_scope_(NULL),
       inlined_count_(0),
       globals_(10, info->zone()),
       inline_bailout_(false) {
@@ skipping 10052 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal