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1 // Copyright 2018 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #include "src/builtins/growable-fixed-array-gen.h"
6 
7 #include "src/compiler/code-assembler.h"
8 
9 namespace v8 {
10 namespace internal {
11 
Push(const TNode<Object> value)12 void GrowableFixedArray::Push(const TNode<Object> value) {
13   const TNode<IntPtrT> length = var_length_.value();
14   const TNode<IntPtrT> capacity = var_capacity_.value();
15 
16   Label grow(this), store(this);
17   Branch(IntPtrEqual(capacity, length), &grow, &store);
18 
19   BIND(&grow);
20   {
21     var_capacity_ = NewCapacity(capacity);
22     var_array_ = ResizeFixedArray(length, var_capacity_.value());
23 
24     Goto(&store);
25   }
26 
27   BIND(&store);
28   {
29     const TNode<FixedArray> array = var_array_.value();
30     UnsafeStoreFixedArrayElement(array, length, value);
31 
32     var_length_ = IntPtrAdd(length, IntPtrConstant(1));
33   }
34 }
35 
ToFixedArray()36 TNode<FixedArray> GrowableFixedArray::ToFixedArray() {
37   return ResizeFixedArray(length(), length());
38 }
39 
ToJSArray(const TNode<Context> context)40 TNode<JSArray> GrowableFixedArray::ToJSArray(const TNode<Context> context) {
41   const ElementsKind kind = PACKED_ELEMENTS;
42 
43   const TNode<NativeContext> native_context = LoadNativeContext(context);
44   const TNode<Map> array_map = LoadJSArrayElementsMap(kind, native_context);
45 
46   // Shrink to fit if necessary.
47   {
48     Label next(this);
49 
50     const TNode<IntPtrT> length = var_length_.value();
51     const TNode<IntPtrT> capacity = var_capacity_.value();
52 
53     GotoIf(WordEqual(length, capacity), &next);
54 
55     var_array_ = ResizeFixedArray(length, length);
56     var_capacity_ = length;
57     Goto(&next);
58 
59     BIND(&next);
60   }
61 
62   const TNode<Smi> result_length = SmiTag(length());
63   const TNode<JSArray> result =
64       AllocateJSArray(array_map, var_array_.value(), result_length);
65   return result;
66 }
67 
NewCapacity(TNode<IntPtrT> current_capacity)68 TNode<IntPtrT> GrowableFixedArray::NewCapacity(
69     TNode<IntPtrT> current_capacity) {
70   CSA_ASSERT(this,
71              IntPtrGreaterThanOrEqual(current_capacity, IntPtrConstant(0)));
72 
73   // Growth rate is analog to JSObject::NewElementsCapacity:
74   // new_capacity = (current_capacity + (current_capacity >> 1)) + 16.
75 
76   const TNode<IntPtrT> new_capacity =
77       IntPtrAdd(IntPtrAdd(current_capacity, WordShr(current_capacity, 1)),
78                 IntPtrConstant(16));
79 
80   return new_capacity;
81 }
82 
ResizeFixedArray(const TNode<IntPtrT> element_count,const TNode<IntPtrT> new_capacity)83 TNode<FixedArray> GrowableFixedArray::ResizeFixedArray(
84     const TNode<IntPtrT> element_count, const TNode<IntPtrT> new_capacity) {
85   CSA_ASSERT(this, IntPtrGreaterThanOrEqual(element_count, IntPtrConstant(0)));
86   CSA_ASSERT(this, IntPtrGreaterThanOrEqual(new_capacity, IntPtrConstant(0)));
87   CSA_ASSERT(this, IntPtrGreaterThanOrEqual(new_capacity, element_count));
88 
89   const TNode<FixedArray> from_array = var_array_.value();
90 
91   CodeStubAssembler::ExtractFixedArrayFlags flags;
92   flags |= CodeStubAssembler::ExtractFixedArrayFlag::kFixedArrays;
93   TNode<FixedArray> to_array = CAST(ExtractFixedArray(
94       from_array, base::Optional<TNode<IntPtrT>>(base::nullopt),
95       base::Optional<TNode<IntPtrT>>(element_count),
96       base::Optional<TNode<IntPtrT>>(new_capacity), flags));
97 
98   return to_array;
99 }
100 
101 }  // namespace internal
102 }  // namespace v8
103