1 /*
2 * Copyright (C) 2018 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "intrinsic_objects.h"
18
19 #include "art_field-inl.h"
20 #include "base/logging.h"
21 #include "class_root.h"
22 #include "handle.h"
23 #include "obj_ptr-inl.h"
24 #include "mirror/object_array-alloc-inl.h"
25 #include "mirror/object_array-inl.h"
26
27 namespace art {
28
LookupIntegerCache(Thread * self,ClassLinker * class_linker)29 static ObjPtr<mirror::ObjectArray<mirror::Object>> LookupIntegerCache(Thread* self,
30 ClassLinker* class_linker)
31 REQUIRES_SHARED(Locks::mutator_lock_) {
32 ObjPtr<mirror::Class> integer_cache_class = class_linker->LookupClass(
33 self, "Ljava/lang/Integer$IntegerCache;", /* class_loader= */ nullptr);
34 if (integer_cache_class == nullptr || !integer_cache_class->IsInitialized()) {
35 return nullptr;
36 }
37 ArtField* cache_field =
38 integer_cache_class->FindDeclaredStaticField("cache", "[Ljava/lang/Integer;");
39 CHECK(cache_field != nullptr);
40 ObjPtr<mirror::ObjectArray<mirror::Object>> integer_cache =
41 ObjPtr<mirror::ObjectArray<mirror::Object>>::DownCast(
42 cache_field->GetObject(integer_cache_class));
43 CHECK(integer_cache != nullptr);
44 return integer_cache;
45 }
46
AllocateBootImageLiveObjects(Thread * self,ClassLinker * class_linker)47 ObjPtr<mirror::ObjectArray<mirror::Object>> IntrinsicObjects::AllocateBootImageLiveObjects(
48 Thread* self,
49 ClassLinker* class_linker) REQUIRES_SHARED(Locks::mutator_lock_) {
50 // The objects used for the Integer.valueOf() intrinsic must remain live even if references
51 // to them are removed using reflection. Image roots are not accessible through reflection,
52 // so the array we construct here shall keep them alive.
53 StackHandleScope<1> hs(self);
54 Handle<mirror::ObjectArray<mirror::Object>> integer_cache =
55 hs.NewHandle(LookupIntegerCache(self, class_linker));
56 size_t live_objects_size =
57 (integer_cache != nullptr) ? (/* cache */ 1u + integer_cache->GetLength()) : 0u;
58 ObjPtr<mirror::ObjectArray<mirror::Object>> live_objects =
59 mirror::ObjectArray<mirror::Object>::Alloc(
60 self, GetClassRoot<mirror::ObjectArray<mirror::Object>>(class_linker), live_objects_size);
61 int32_t index = 0;
62 if (integer_cache != nullptr) {
63 live_objects->Set(index++, integer_cache.Get());
64 for (int32_t i = 0, length = integer_cache->GetLength(); i != length; ++i) {
65 live_objects->Set(index++, integer_cache->Get(i));
66 }
67 }
68 CHECK_EQ(index, live_objects->GetLength());
69
70 if (kIsDebugBuild && integer_cache != nullptr) {
71 CHECK_EQ(integer_cache.Get(), GetIntegerValueOfCache(live_objects));
72 for (int32_t i = 0, len = integer_cache->GetLength(); i != len; ++i) {
73 CHECK_EQ(integer_cache->GetWithoutChecks(i), GetIntegerValueOfObject(live_objects, i));
74 }
75 }
76 return live_objects;
77 }
78
GetIntegerValueOfCache(ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects)79 ObjPtr<mirror::ObjectArray<mirror::Object>> IntrinsicObjects::GetIntegerValueOfCache(
80 ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects) {
81 DCHECK(boot_image_live_objects != nullptr);
82 if (boot_image_live_objects->GetLength() == 0u) {
83 return nullptr; // No intrinsic objects.
84 }
85 // No need for read barrier for boot image object or for verifying the value that was just stored.
86 ObjPtr<mirror::Object> result =
87 boot_image_live_objects->GetWithoutChecks<kVerifyNone, kWithoutReadBarrier>(0);
88 DCHECK(result != nullptr);
89 DCHECK(result->IsObjectArray());
90 DCHECK(result->GetClass()->DescriptorEquals("[Ljava/lang/Integer;"));
91 return ObjPtr<mirror::ObjectArray<mirror::Object>>::DownCast(result);
92 }
93
GetIntegerValueOfObject(ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects,uint32_t index)94 ObjPtr<mirror::Object> IntrinsicObjects::GetIntegerValueOfObject(
95 ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects,
96 uint32_t index) {
97 DCHECK(boot_image_live_objects != nullptr);
98 DCHECK_NE(boot_image_live_objects->GetLength(), 0);
99 DCHECK_LT(index,
100 static_cast<uint32_t>(GetIntegerValueOfCache(boot_image_live_objects)->GetLength()));
101
102 // No need for read barrier for boot image object or for verifying the value that was just stored.
103 ObjPtr<mirror::Object> result =
104 boot_image_live_objects->GetWithoutChecks<kVerifyNone, kWithoutReadBarrier>(
105 /* skip the IntegerCache.cache */ 1u + index);
106 DCHECK(result != nullptr);
107 DCHECK(result->GetClass()->DescriptorEquals("Ljava/lang/Integer;"));
108 return result;
109 }
110
GetIntegerValueOfArrayDataOffset(ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects)111 MemberOffset IntrinsicObjects::GetIntegerValueOfArrayDataOffset(
112 ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects) {
113 DCHECK_NE(boot_image_live_objects->GetLength(), 0);
114 MemberOffset result = mirror::ObjectArray<mirror::Object>::OffsetOfElement(1u);
115 DCHECK_EQ(GetIntegerValueOfObject(boot_image_live_objects, 0u),
116 (boot_image_live_objects
117 ->GetFieldObject<mirror::Object, kVerifyNone, kWithoutReadBarrier>(result)));
118 return result;
119 }
120
121 } // namespace art
122