1// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
2// for details. All rights reserved. Use of this source code is governed by a
3// BSD-style license that can be found in the LICENSE file.
4
5#include "vm/heap/weak_code.h"
6
7#include "platform/assert.h"
8
9#include "vm/code_patcher.h"
10#include "vm/object.h"
11#include "vm/runtime_entry.h"
12#include "vm/stack_frame.h"
13
14namespace dart {
15
16bool WeakCodeReferences::HasCodes() const {
17 return !array_.IsNull() && (array_.Length() > 0);
18}
19
20void WeakCodeReferences::Register(const Code& value) {
21 if (!array_.IsNull()) {
22 // Try to find and reuse cleared WeakProperty to avoid allocating new one.
23 WeakProperty& weak_property = WeakProperty::Handle();
24 for (intptr_t i = 0; i < array_.Length(); i++) {
25 weak_property ^= array_.At(i);
26 if (weak_property.key() == Code::null()) {
27 // Empty property found. Reuse it.
28 weak_property.set_key(value);
29 return;
30 }
31 }
32 }
33
34 const WeakProperty& weak_property =
35 WeakProperty::Handle(WeakProperty::New(Heap::kOld));
36 weak_property.set_key(value);
37
38 intptr_t length = array_.IsNull() ? 0 : array_.Length();
39 const Array& new_array =
40 Array::Handle(Array::Grow(array_, length + 1, Heap::kOld));
41 new_array.SetAt(length, weak_property);
42 UpdateArrayTo(new_array);
43}
44
45bool WeakCodeReferences::IsOptimizedCode(const Array& dependent_code,
46 const Code& code) {
47 if (!code.is_optimized()) {
48 return false;
49 }
50 WeakProperty& weak_property = WeakProperty::Handle();
51 for (intptr_t i = 0; i < dependent_code.Length(); i++) {
52 weak_property ^= dependent_code.At(i);
53 if (code.raw() == weak_property.key()) {
54 return true;
55 }
56 }
57 return false;
58}
59
60void WeakCodeReferences::DisableCode() {
61 Thread* thread = Thread::Current();
62 const Array& code_objects = Array::Handle(thread->zone(), array_.raw());
63#if defined(DART_PRECOMPILED_RUNTIME)
64 ASSERT(code_objects.IsNull());
65 return;
66#else
67 if (code_objects.IsNull()) {
68 return;
69 }
70
71 UpdateArrayTo(Object::null_array());
72 // Disable all code on stack.
73 Code& code = Code::Handle();
74 {
75 DartFrameIterator iterator(thread,
76 StackFrameIterator::kNoCrossThreadIteration);
77 StackFrame* frame = iterator.NextFrame();
78 while (frame != NULL) {
79 if (!frame->is_interpreted()) {
80 code = frame->LookupDartCode();
81 if (IsOptimizedCode(code_objects, code)) {
82 ReportDeoptimization(code);
83 DeoptimizeAt(code, frame);
84 }
85 }
86 frame = iterator.NextFrame();
87 }
88 }
89
90 // Switch functions that use dependent code to unoptimized code.
91 WeakProperty& weak_property = WeakProperty::Handle();
92 Object& owner = Object::Handle();
93 Function& function = Function::Handle();
94 for (intptr_t i = 0; i < code_objects.Length(); i++) {
95 weak_property ^= code_objects.At(i);
96 code ^= weak_property.key();
97 if (code.IsNull()) {
98 // Code was garbage collected already.
99 continue;
100 }
101 owner = code.owner();
102 if (owner.IsFunction()) {
103 function ^= owner.raw();
104 } else if (owner.IsClass()) {
105 Class& cls = Class::Handle();
106 cls ^= owner.raw();
107 cls.DisableAllocationStub();
108 continue;
109 } else if (owner.IsNull()) {
110 code.Print();
111 continue;
112 }
113
114 // If function uses dependent code switch it to unoptimized.
115 if (code.is_optimized() && (function.CurrentCode() == code.raw())) {
116 ReportSwitchingCode(code);
117 function.SwitchToUnoptimizedCode();
118 } else if (function.unoptimized_code() == code.raw()) {
119 ReportSwitchingCode(code);
120 function.SetWasCompiled(false);
121 function.ClearICDataArray();
122 // Remove the code object from the function. The next time the
123 // function is invoked, it will be compiled again.
124 function.ClearCode();
125 // Invalidate the old code object so existing references to it
126 // (from optimized code) will be patched when invoked.
127 if (!code.IsDisabled()) {
128 code.DisableDartCode();
129 }
130 } else {
131 // Make non-OSR code non-entrant.
132 if (!code.IsDisabled()) {
133 ReportSwitchingCode(code);
134 code.DisableDartCode();
135 }
136 }
137 }
138#endif // defined(DART_PRECOMPILED_RUNTIME)
139}
140
141} // namespace dart
142