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| 1 // Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a | 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. | 3 // BSD-style license that can be found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef RUNTIME_VM_BECOME_H_ | 5 #ifndef RUNTIME_VM_BECOME_H_ |
| 6 #define RUNTIME_VM_BECOME_H_ | 6 #define RUNTIME_VM_BECOME_H_ |
| 7 | 7 |
| 8 #include "vm/allocation.h" | 8 #include "vm/allocation.h" |
| 9 #include "vm/raw_object.h" | 9 #include "vm/raw_object.h" |
| 10 | 10 |
| 11 namespace dart { | 11 namespace dart { |
| 12 | 12 |
| 13 class Array; | 13 class Array; |
| 14 | 14 |
| 15 // Objects that are a source in a become are tranformed into forwarding | 15 // Objects that are a source in a become are tranformed into forwarding |
| 16 // corpses pointing to the corresponding target. Forwarding corpses have the | 16 // corpses pointing to the corresponding target. Forwarding corpses have the |
| 17 // same heap sizes as the source object to ensure the heap remains walkable. | 17 // same heap sizes as the source object to ensure the heap remains walkable. |
| 18 // If the heap sizes is small enough to be encoded in the size field of the | 18 // If the heap sizes is small enough to be encoded in the size field of the |
| 19 // header, a forwarding corpse consists only of a header and the target pointer. | 19 // header, a forwarding corpse consists only of a header and the target pointer. |
| 20 // If the heap size is too big to be encoded in the header's size field, the | 20 // If the heap size is too big to be encoded in the header's size field, the |
| 21 // word after the target pointer contains the size. This is the same | 21 // word after the target pointer contains the size. This is the same |
| 22 // representation as a FreeListElement. | 22 // representation as a FreeListElement. |
| 23 class ForwardingCorpse { | 23 class ForwardingCorpse { |
| 24 public: | 24 public: |
| 25 RawObject* target() const { | 25 RawObject* target() const { return target_; } |
| 26 return target_; | 26 void set_target(RawObject* target) { target_ = target; } |
| 27 } | |
| 28 void set_target(RawObject* target) { | |
| 29 target_ = target; | |
| 30 } | |
| 31 | 27 |
| 32 intptr_t Size() { | 28 intptr_t Size() { |
| 33 intptr_t size = RawObject::SizeTag::decode(tags_); | 29 intptr_t size = RawObject::SizeTag::decode(tags_); |
| 34 if (size != 0) return size; | 30 if (size != 0) return size; |
| 35 return *SizeAddress(); | 31 return *SizeAddress(); |
| 36 } | 32 } |
| 37 | 33 |
| 38 static ForwardingCorpse* AsForwarder(uword addr, intptr_t size); | 34 static ForwardingCorpse* AsForwarder(uword addr, intptr_t size); |
| 39 | 35 |
| 40 static void InitOnce(); | 36 static void InitOnce(); |
| 41 | 37 |
| 42 // Used to allocate class for forwarding corpses in Object::InitOnce. | 38 // Used to allocate class for forwarding corpses in Object::InitOnce. |
| 43 class FakeInstance { | 39 class FakeInstance { |
| 44 public: | 40 public: |
| 45 FakeInstance() { } | 41 FakeInstance() {} |
| 46 static cpp_vtable vtable() { return 0; } | 42 static cpp_vtable vtable() { return 0; } |
| 47 static intptr_t InstanceSize() { return 0; } | 43 static intptr_t InstanceSize() { return 0; } |
| 48 static intptr_t NextFieldOffset() { return -kWordSize; } | 44 static intptr_t NextFieldOffset() { return -kWordSize; } |
| 49 static const ClassId kClassId = kForwardingCorpse; | 45 static const ClassId kClassId = kForwardingCorpse; |
| 50 static bool IsInstance() { return true; } | 46 static bool IsInstance() { return true; } |
| 51 | 47 |
| 52 private: | 48 private: |
| 53 DISALLOW_ALLOCATION(); | 49 DISALLOW_ALLOCATION(); |
| 54 DISALLOW_COPY_AND_ASSIGN(FakeInstance); | 50 DISALLOW_COPY_AND_ASSIGN(FakeInstance); |
| 55 }; | 51 }; |
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| 86 // (used for morphic instances during reload). | 82 // (used for morphic instances during reload). |
| 87 static void MakeDummyObject(const Instance& instance); | 83 static void MakeDummyObject(const Instance& instance); |
| 88 | 84 |
| 89 private: | 85 private: |
| 90 static void CrashDump(RawObject* before_obj, RawObject* after_obj); | 86 static void CrashDump(RawObject* before_obj, RawObject* after_obj); |
| 91 }; | 87 }; |
| 92 | 88 |
| 93 } // namespace dart | 89 } // namespace dart |
| 94 | 90 |
| 95 #endif // RUNTIME_VM_BECOME_H_ | 91 #endif // RUNTIME_VM_BECOME_H_ |
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