1 // Copyright 2015 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/heap/array-buffer-tracker.h"
6 #include "src/heap/heap.h"
7 #include "src/isolate.h"
8 #include "src/objects.h"
9 #include "src/objects-inl.h"
10 #include "src/v8.h"
11 
12 namespace v8 {
13 namespace internal {
14 
~ArrayBufferTracker()15 ArrayBufferTracker::~ArrayBufferTracker() {
16   Isolate* isolate = heap()->isolate();
17   size_t freed_memory = 0;
18   for (auto& buffer : live_array_buffers_) {
19     isolate->array_buffer_allocator()->Free(buffer.first, buffer.second);
20     freed_memory += buffer.second;
21   }
22   for (auto& buffer : live_array_buffers_for_scavenge_) {
23     isolate->array_buffer_allocator()->Free(buffer.first, buffer.second);
24     freed_memory += buffer.second;
25   }
26   live_array_buffers_.clear();
27   live_array_buffers_for_scavenge_.clear();
28   not_yet_discovered_array_buffers_.clear();
29   not_yet_discovered_array_buffers_for_scavenge_.clear();
30 
31   if (freed_memory > 0) {
32     heap()->update_amount_of_external_allocated_memory(
33         -static_cast<int64_t>(freed_memory));
34   }
35 }
36 
37 
RegisterNew(JSArrayBuffer * buffer)38 void ArrayBufferTracker::RegisterNew(JSArrayBuffer* buffer) {
39   void* data = buffer->backing_store();
40   if (!data) return;
41 
42   bool in_new_space = heap()->InNewSpace(buffer);
43   size_t length = NumberToSize(heap()->isolate(), buffer->byte_length());
44   if (in_new_space) {
45     live_array_buffers_for_scavenge_[data] = length;
46   } else {
47     live_array_buffers_[data] = length;
48   }
49 
50   // We may go over the limit of externally allocated memory here. We call the
51   // api function to trigger a GC in this case.
52   reinterpret_cast<v8::Isolate*>(heap()->isolate())
53       ->AdjustAmountOfExternalAllocatedMemory(length);
54 }
55 
56 
Unregister(JSArrayBuffer * buffer)57 void ArrayBufferTracker::Unregister(JSArrayBuffer* buffer) {
58   void* data = buffer->backing_store();
59   if (!data) return;
60 
61   bool in_new_space = heap()->InNewSpace(buffer);
62   std::map<void*, size_t>* live_buffers =
63       in_new_space ? &live_array_buffers_for_scavenge_ : &live_array_buffers_;
64   std::map<void*, size_t>* not_yet_discovered_buffers =
65       in_new_space ? &not_yet_discovered_array_buffers_for_scavenge_
66                    : &not_yet_discovered_array_buffers_;
67 
68   DCHECK(live_buffers->count(data) > 0);
69 
70   size_t length = (*live_buffers)[data];
71   live_buffers->erase(data);
72   not_yet_discovered_buffers->erase(data);
73 
74   heap()->update_amount_of_external_allocated_memory(
75       -static_cast<int64_t>(length));
76 }
77 
78 
MarkLive(JSArrayBuffer * buffer)79 void ArrayBufferTracker::MarkLive(JSArrayBuffer* buffer) {
80   void* data = buffer->backing_store();
81 
82   // ArrayBuffer might be in the middle of being constructed.
83   if (data == heap()->undefined_value()) return;
84   if (heap()->InNewSpace(buffer)) {
85     not_yet_discovered_array_buffers_for_scavenge_.erase(data);
86   } else {
87     not_yet_discovered_array_buffers_.erase(data);
88   }
89 }
90 
91 
FreeDead(bool from_scavenge)92 void ArrayBufferTracker::FreeDead(bool from_scavenge) {
93   size_t freed_memory = 0;
94   Isolate* isolate = heap()->isolate();
95   for (auto& buffer : not_yet_discovered_array_buffers_for_scavenge_) {
96     isolate->array_buffer_allocator()->Free(buffer.first, buffer.second);
97     freed_memory += buffer.second;
98     live_array_buffers_for_scavenge_.erase(buffer.first);
99   }
100 
101   if (!from_scavenge) {
102     for (auto& buffer : not_yet_discovered_array_buffers_) {
103       isolate->array_buffer_allocator()->Free(buffer.first, buffer.second);
104       freed_memory += buffer.second;
105       live_array_buffers_.erase(buffer.first);
106     }
107   }
108 
109   not_yet_discovered_array_buffers_for_scavenge_ =
110       live_array_buffers_for_scavenge_;
111   if (!from_scavenge) not_yet_discovered_array_buffers_ = live_array_buffers_;
112 
113   // Do not call through the api as this code is triggered while doing a GC.
114   heap()->update_amount_of_external_allocated_memory(
115       -static_cast<int64_t>(freed_memory));
116 }
117 
118 
PrepareDiscoveryInNewSpace()119 void ArrayBufferTracker::PrepareDiscoveryInNewSpace() {
120   not_yet_discovered_array_buffers_for_scavenge_ =
121       live_array_buffers_for_scavenge_;
122 }
123 
124 
Promote(JSArrayBuffer * buffer)125 void ArrayBufferTracker::Promote(JSArrayBuffer* buffer) {
126   if (buffer->is_external()) return;
127   void* data = buffer->backing_store();
128   if (!data) return;
129   // ArrayBuffer might be in the middle of being constructed.
130   if (data == heap()->undefined_value()) return;
131   DCHECK(live_array_buffers_for_scavenge_.count(data) > 0);
132   live_array_buffers_[data] = live_array_buffers_for_scavenge_[data];
133   live_array_buffers_for_scavenge_.erase(data);
134   not_yet_discovered_array_buffers_for_scavenge_.erase(data);
135 }
136 
137 }  // namespace internal
138 }  // namespace v8
139