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      1 /*
      2  * Copyright (C) 2016 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 "class_ext-inl.h"
     18 
     19 #include "art_method-inl.h"
     20 #include "base/casts.h"
     21 #include "base/enums.h"
     22 #include "base/utils.h"
     23 #include "class-inl.h"
     24 #include "dex/dex_file-inl.h"
     25 #include "gc/accounting/card_table-inl.h"
     26 #include "object-inl.h"
     27 #include "object_array.h"
     28 #include "stack_trace_element.h"
     29 #include "well_known_classes.h"
     30 
     31 namespace art {
     32 namespace mirror {
     33 
     34 GcRoot<Class> ClassExt::dalvik_system_ClassExt_;
     35 
     36 uint32_t ClassExt::ClassSize(PointerSize pointer_size) {
     37   uint32_t vtable_entries = Object::kVTableLength;
     38   return Class::ComputeClassSize(true, vtable_entries, 0, 0, 0, 0, 0, pointer_size);
     39 }
     40 
     41 void ClassExt::SetObsoleteArrays(ObjPtr<PointerArray> methods,
     42                                  ObjPtr<ObjectArray<DexCache>> dex_caches) {
     43   CHECK_EQ(methods.IsNull(), dex_caches.IsNull());
     44   auto obsolete_dex_cache_off = OFFSET_OF_OBJECT_MEMBER(ClassExt, obsolete_dex_caches_);
     45   auto obsolete_methods_off = OFFSET_OF_OBJECT_MEMBER(ClassExt, obsolete_methods_);
     46   DCHECK(!Runtime::Current()->IsActiveTransaction());
     47   SetFieldObject<false>(obsolete_dex_cache_off, dex_caches.Ptr());
     48   SetFieldObject<false>(obsolete_methods_off, methods.Ptr());
     49 }
     50 
     51 // We really need to be careful how we update this. If we ever in the future make it so that
     52 // these arrays are written into without all threads being suspended we have a race condition! This
     53 // race could cause obsolete methods to be missed.
     54 bool ClassExt::ExtendObsoleteArrays(Thread* self, uint32_t increase) {
     55   // TODO It would be good to check that we have locked the class associated with this ClassExt.
     56   StackHandleScope<5> hs(self);
     57   Handle<ClassExt> h_this(hs.NewHandle(this));
     58   Handle<PointerArray> old_methods(hs.NewHandle(h_this->GetObsoleteMethods()));
     59   Handle<ObjectArray<DexCache>> old_dex_caches(hs.NewHandle(h_this->GetObsoleteDexCaches()));
     60   ClassLinker* cl = Runtime::Current()->GetClassLinker();
     61   size_t new_len;
     62   if (old_methods == nullptr) {
     63     CHECK(old_dex_caches == nullptr);
     64     new_len = increase;
     65   } else {
     66     CHECK_EQ(old_methods->GetLength(), old_dex_caches->GetLength());
     67     new_len = increase + old_methods->GetLength();
     68   }
     69   Handle<PointerArray> new_methods(hs.NewHandle<PointerArray>(
     70       cl->AllocPointerArray(self, new_len)));
     71   if (new_methods.IsNull()) {
     72     // Fail.
     73     self->AssertPendingOOMException();
     74     return false;
     75   }
     76   Handle<ObjectArray<DexCache>> new_dex_caches(hs.NewHandle<ObjectArray<DexCache>>(
     77       ObjectArray<DexCache>::Alloc(self,
     78                                    cl->FindClass(self,
     79                                                  "[Ljava/lang/DexCache;",
     80                                                  ScopedNullHandle<ClassLoader>()),
     81                                    new_len)));
     82   if (new_dex_caches.IsNull()) {
     83     // Fail.
     84     self->AssertPendingOOMException();
     85     return false;
     86   }
     87 
     88   if (!old_methods.IsNull()) {
     89     // Copy the old contents.
     90     new_methods->Memcpy(0,
     91                         old_methods.Get(),
     92                         0,
     93                         old_methods->GetLength(),
     94                         cl->GetImagePointerSize());
     95     new_dex_caches->AsObjectArray<Object>()->AssignableCheckingMemcpy<false>(
     96         0, old_dex_caches->AsObjectArray<Object>(), 0, old_dex_caches->GetLength(), false);
     97   }
     98   // Set the fields.
     99   h_this->SetObsoleteArrays(new_methods.Get(), new_dex_caches.Get());
    100 
    101   return true;
    102 }
    103 
    104 ClassExt* ClassExt::Alloc(Thread* self) {
    105   DCHECK(dalvik_system_ClassExt_.Read() != nullptr);
    106   return down_cast<ClassExt*>(dalvik_system_ClassExt_.Read()->AllocObject(self).Ptr());
    107 }
    108 
    109 void ClassExt::SetVerifyError(ObjPtr<Object> err) {
    110   if (Runtime::Current()->IsActiveTransaction()) {
    111     SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(ClassExt, verify_error_), err);
    112   } else {
    113     SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(ClassExt, verify_error_), err);
    114   }
    115 }
    116 
    117 void ClassExt::SetOriginalDexFile(ObjPtr<Object> bytes) {
    118   DCHECK(!Runtime::Current()->IsActiveTransaction());
    119   SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(ClassExt, original_dex_file_), bytes);
    120 }
    121 
    122 void ClassExt::SetClass(ObjPtr<Class> dalvik_system_ClassExt) {
    123   CHECK(dalvik_system_ClassExt != nullptr);
    124   dalvik_system_ClassExt_ = GcRoot<Class>(dalvik_system_ClassExt);
    125 }
    126 
    127 void ClassExt::ResetClass() {
    128   CHECK(!dalvik_system_ClassExt_.IsNull());
    129   dalvik_system_ClassExt_ = GcRoot<Class>(nullptr);
    130 }
    131 
    132 void ClassExt::VisitRoots(RootVisitor* visitor) {
    133   dalvik_system_ClassExt_.VisitRootIfNonNull(visitor, RootInfo(kRootStickyClass));
    134 }
    135 
    136 }  // namespace mirror
    137 }  // namespace art
    138