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1 /*
2  * Copyright (C) 2011 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.h"
18 
19 #include "android-base/stringprintf.h"
20 
21 #include "art_field-inl.h"
22 #include "art_method-inl.h"
23 #include "class_ext.h"
24 #include "class_linker-inl.h"
25 #include "class_loader.h"
26 #include "class-inl.h"
27 #include "dex_cache.h"
28 #include "dex_file-inl.h"
29 #include "dex_file_annotations.h"
30 #include "gc/accounting/card_table-inl.h"
31 #include "handle_scope-inl.h"
32 #include "method.h"
33 #include "object_array-inl.h"
34 #include "object-inl.h"
35 #include "object-refvisitor-inl.h"
36 #include "object_lock.h"
37 #include "runtime.h"
38 #include "thread.h"
39 #include "throwable.h"
40 #include "utils.h"
41 #include "well_known_classes.h"
42 
43 namespace art {
44 namespace mirror {
45 
46 using android::base::StringPrintf;
47 
48 GcRoot<Class> Class::java_lang_Class_;
49 
SetClassClass(ObjPtr<Class> java_lang_Class)50 void Class::SetClassClass(ObjPtr<Class> java_lang_Class) {
51   CHECK(java_lang_Class_.IsNull())
52       << java_lang_Class_.Read()
53       << " " << java_lang_Class;
54   CHECK(java_lang_Class != nullptr);
55   java_lang_Class->SetClassFlags(kClassFlagClass);
56   java_lang_Class_ = GcRoot<Class>(java_lang_Class);
57 }
58 
ResetClass()59 void Class::ResetClass() {
60   CHECK(!java_lang_Class_.IsNull());
61   java_lang_Class_ = GcRoot<Class>(nullptr);
62 }
63 
VisitRoots(RootVisitor * visitor)64 void Class::VisitRoots(RootVisitor* visitor) {
65   java_lang_Class_.VisitRootIfNonNull(visitor, RootInfo(kRootStickyClass));
66 }
67 
EnsureExtDataPresent(Thread * self)68 ClassExt* Class::EnsureExtDataPresent(Thread* self) {
69   ObjPtr<ClassExt> existing(GetExtData());
70   if (!existing.IsNull()) {
71     return existing.Ptr();
72   }
73   StackHandleScope<3> hs(self);
74   // Handlerize 'this' since we are allocating here.
75   Handle<Class> h_this(hs.NewHandle(this));
76   // Clear exception so we can allocate.
77   Handle<Throwable> throwable(hs.NewHandle(self->GetException()));
78   self->ClearException();
79   // Allocate the ClassExt
80   Handle<ClassExt> new_ext(hs.NewHandle(ClassExt::Alloc(self)));
81   if (new_ext == nullptr) {
82     // OOM allocating the classExt.
83     // TODO Should we restore the suppressed exception?
84     self->AssertPendingOOMException();
85     return nullptr;
86   } else {
87     MemberOffset ext_offset(OFFSET_OF_OBJECT_MEMBER(Class, ext_data_));
88     bool set;
89     // Set the ext_data_ field using CAS semantics.
90     if (Runtime::Current()->IsActiveTransaction()) {
91       set = h_this->CasFieldStrongSequentiallyConsistentObject<true>(ext_offset,
92                                                                      ObjPtr<ClassExt>(nullptr),
93                                                                      new_ext.Get());
94     } else {
95       set = h_this->CasFieldStrongSequentiallyConsistentObject<false>(ext_offset,
96                                                                       ObjPtr<ClassExt>(nullptr),
97                                                                       new_ext.Get());
98     }
99     ObjPtr<ClassExt> ret(set ? new_ext.Get() : h_this->GetExtData());
100     DCHECK(!set || h_this->GetExtData() == new_ext.Get());
101     CHECK(!ret.IsNull());
102     // Restore the exception if there was one.
103     if (throwable != nullptr) {
104       self->SetException(throwable.Get());
105     }
106     return ret.Ptr();
107   }
108 }
109 
SetStatus(Handle<Class> h_this,Status new_status,Thread * self)110 void Class::SetStatus(Handle<Class> h_this, Status new_status, Thread* self) {
111   Status old_status = h_this->GetStatus();
112   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
113   bool class_linker_initialized = class_linker != nullptr && class_linker->IsInitialized();
114   if (LIKELY(class_linker_initialized)) {
115     if (UNLIKELY(new_status <= old_status &&
116                  new_status != kStatusErrorUnresolved &&
117                  new_status != kStatusErrorResolved &&
118                  new_status != kStatusRetired)) {
119       LOG(FATAL) << "Unexpected change back of class status for " << h_this->PrettyClass()
120                  << " " << old_status << " -> " << new_status;
121     }
122     if (new_status >= kStatusResolved || old_status >= kStatusResolved) {
123       // When classes are being resolved the resolution code should hold the lock.
124       CHECK_EQ(h_this->GetLockOwnerThreadId(), self->GetThreadId())
125             << "Attempt to change status of class while not holding its lock: "
126             << h_this->PrettyClass() << " " << old_status << " -> " << new_status;
127     }
128   }
129   if (UNLIKELY(IsErroneous(new_status))) {
130     CHECK(!h_this->IsErroneous())
131         << "Attempt to set as erroneous an already erroneous class "
132         << h_this->PrettyClass()
133         << " old_status: " << old_status << " new_status: " << new_status;
134     CHECK_EQ(new_status == kStatusErrorResolved, old_status >= kStatusResolved);
135     if (VLOG_IS_ON(class_linker)) {
136       LOG(ERROR) << "Setting " << h_this->PrettyDescriptor() << " to erroneous.";
137       if (self->IsExceptionPending()) {
138         LOG(ERROR) << "Exception: " << self->GetException()->Dump();
139       }
140     }
141 
142     ObjPtr<ClassExt> ext(h_this->EnsureExtDataPresent(self));
143     if (!ext.IsNull()) {
144       self->AssertPendingException();
145       ext->SetVerifyError(self->GetException());
146     } else {
147       self->AssertPendingOOMException();
148     }
149     self->AssertPendingException();
150   }
151 
152   static_assert(sizeof(Status) == sizeof(uint32_t), "Size of status not equal to uint32");
153   if (Runtime::Current()->IsActiveTransaction()) {
154     h_this->SetField32Volatile<true>(StatusOffset(), new_status);
155   } else {
156     h_this->SetField32Volatile<false>(StatusOffset(), new_status);
157   }
158 
159   // Setting the object size alloc fast path needs to be after the status write so that if the
160   // alloc path sees a valid object size, we would know that it's initialized as long as it has a
161   // load-acquire/fake dependency.
162   if (new_status == kStatusInitialized && !h_this->IsVariableSize()) {
163     DCHECK_EQ(h_this->GetObjectSizeAllocFastPath(), std::numeric_limits<uint32_t>::max());
164     // Finalizable objects must always go slow path.
165     if (!h_this->IsFinalizable()) {
166       h_this->SetObjectSizeAllocFastPath(RoundUp(h_this->GetObjectSize(), kObjectAlignment));
167     }
168   }
169 
170   if (!class_linker_initialized) {
171     // When the class linker is being initialized its single threaded and by definition there can be
172     // no waiters. During initialization classes may appear temporary but won't be retired as their
173     // size was statically computed.
174   } else {
175     // Classes that are being resolved or initialized need to notify waiters that the class status
176     // changed. See ClassLinker::EnsureResolved and ClassLinker::WaitForInitializeClass.
177     if (h_this->IsTemp()) {
178       // Class is a temporary one, ensure that waiters for resolution get notified of retirement
179       // so that they can grab the new version of the class from the class linker's table.
180       CHECK_LT(new_status, kStatusResolved) << h_this->PrettyDescriptor();
181       if (new_status == kStatusRetired || new_status == kStatusErrorUnresolved) {
182         h_this->NotifyAll(self);
183       }
184     } else {
185       CHECK_NE(new_status, kStatusRetired);
186       if (old_status >= kStatusResolved || new_status >= kStatusResolved) {
187         h_this->NotifyAll(self);
188       }
189     }
190   }
191 }
192 
SetDexCache(ObjPtr<DexCache> new_dex_cache)193 void Class::SetDexCache(ObjPtr<DexCache> new_dex_cache) {
194   SetFieldObjectTransaction(OFFSET_OF_OBJECT_MEMBER(Class, dex_cache_), new_dex_cache);
195 }
196 
SetClassSize(uint32_t new_class_size)197 void Class::SetClassSize(uint32_t new_class_size) {
198   if (kIsDebugBuild && new_class_size < GetClassSize()) {
199     DumpClass(LOG_STREAM(FATAL_WITHOUT_ABORT), kDumpClassFullDetail);
200     LOG(FATAL_WITHOUT_ABORT) << new_class_size << " vs " << GetClassSize();
201     LOG(FATAL) << "class=" << PrettyTypeOf();
202   }
203   SetField32Transaction(OFFSET_OF_OBJECT_MEMBER(Class, class_size_), new_class_size);
204 }
205 
206 // Return the class' name. The exact format is bizarre, but it's the specified behavior for
207 // Class.getName: keywords for primitive types, regular "[I" form for primitive arrays (so "int"
208 // but "[I"), and arrays of reference types written between "L" and ";" but with dots rather than
209 // slashes (so "java.lang.String" but "[Ljava.lang.String;"). Madness.
ComputeName(Handle<Class> h_this)210 String* Class::ComputeName(Handle<Class> h_this) {
211   String* name = h_this->GetName();
212   if (name != nullptr) {
213     return name;
214   }
215   std::string temp;
216   const char* descriptor = h_this->GetDescriptor(&temp);
217   Thread* self = Thread::Current();
218   if ((descriptor[0] != 'L') && (descriptor[0] != '[')) {
219     // The descriptor indicates that this is the class for
220     // a primitive type; special-case the return value.
221     const char* c_name = nullptr;
222     switch (descriptor[0]) {
223     case 'Z': c_name = "boolean"; break;
224     case 'B': c_name = "byte";    break;
225     case 'C': c_name = "char";    break;
226     case 'S': c_name = "short";   break;
227     case 'I': c_name = "int";     break;
228     case 'J': c_name = "long";    break;
229     case 'F': c_name = "float";   break;
230     case 'D': c_name = "double";  break;
231     case 'V': c_name = "void";    break;
232     default:
233       LOG(FATAL) << "Unknown primitive type: " << PrintableChar(descriptor[0]);
234     }
235     name = String::AllocFromModifiedUtf8(self, c_name);
236   } else {
237     // Convert the UTF-8 name to a java.lang.String. The name must use '.' to separate package
238     // components.
239     name = String::AllocFromModifiedUtf8(self, DescriptorToDot(descriptor).c_str());
240   }
241   h_this->SetName(name);
242   return name;
243 }
244 
DumpClass(std::ostream & os,int flags)245 void Class::DumpClass(std::ostream& os, int flags) {
246   if ((flags & kDumpClassFullDetail) == 0) {
247     os << PrettyClass();
248     if ((flags & kDumpClassClassLoader) != 0) {
249       os << ' ' << GetClassLoader();
250     }
251     if ((flags & kDumpClassInitialized) != 0) {
252       os << ' ' << GetStatus();
253     }
254     os << "\n";
255     return;
256   }
257 
258   Thread* const self = Thread::Current();
259   StackHandleScope<2> hs(self);
260   Handle<Class> h_this(hs.NewHandle(this));
261   Handle<Class> h_super(hs.NewHandle(GetSuperClass()));
262   auto image_pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize();
263 
264   std::string temp;
265   os << "----- " << (IsInterface() ? "interface" : "class") << " "
266      << "'" << GetDescriptor(&temp) << "' cl=" << GetClassLoader() << " -----\n",
267   os << "  objectSize=" << SizeOf() << " "
268      << "(" << (h_super != nullptr ? h_super->SizeOf() : -1) << " from super)\n",
269   os << StringPrintf("  access=0x%04x.%04x\n",
270       GetAccessFlags() >> 16, GetAccessFlags() & kAccJavaFlagsMask);
271   if (h_super != nullptr) {
272     os << "  super='" << h_super->PrettyClass() << "' (cl=" << h_super->GetClassLoader()
273        << ")\n";
274   }
275   if (IsArrayClass()) {
276     os << "  componentType=" << PrettyClass(GetComponentType()) << "\n";
277   }
278   const size_t num_direct_interfaces = NumDirectInterfaces();
279   if (num_direct_interfaces > 0) {
280     os << "  interfaces (" << num_direct_interfaces << "):\n";
281     for (size_t i = 0; i < num_direct_interfaces; ++i) {
282       ObjPtr<Class> interface = GetDirectInterface(self, h_this.Get(), i);
283       if (interface == nullptr) {
284         os << StringPrintf("    %2zd: nullptr!\n", i);
285       } else {
286         ObjPtr<ClassLoader> cl = interface->GetClassLoader();
287         os << StringPrintf("    %2zd: %s (cl=%p)\n", i, PrettyClass(interface).c_str(), cl.Ptr());
288       }
289     }
290   }
291   if (!IsLoaded()) {
292     os << "  class not yet loaded";
293   } else {
294     // After this point, this may have moved due to GetDirectInterface.
295     os << "  vtable (" << h_this->NumVirtualMethods() << " entries, "
296         << (h_super != nullptr ? h_super->NumVirtualMethods() : 0) << " in super):\n";
297     for (size_t i = 0; i < NumVirtualMethods(); ++i) {
298       os << StringPrintf("    %2zd: %s\n", i, ArtMethod::PrettyMethod(
299           h_this->GetVirtualMethodDuringLinking(i, image_pointer_size)).c_str());
300     }
301     os << "  direct methods (" << h_this->NumDirectMethods() << " entries):\n";
302     for (size_t i = 0; i < h_this->NumDirectMethods(); ++i) {
303       os << StringPrintf("    %2zd: %s\n", i, ArtMethod::PrettyMethod(
304           h_this->GetDirectMethod(i, image_pointer_size)).c_str());
305     }
306     if (h_this->NumStaticFields() > 0) {
307       os << "  static fields (" << h_this->NumStaticFields() << " entries):\n";
308       if (h_this->IsResolved()) {
309         for (size_t i = 0; i < h_this->NumStaticFields(); ++i) {
310           os << StringPrintf("    %2zd: %s\n", i,
311                              ArtField::PrettyField(h_this->GetStaticField(i)).c_str());
312         }
313       } else {
314         os << "    <not yet available>";
315       }
316     }
317     if (h_this->NumInstanceFields() > 0) {
318       os << "  instance fields (" << h_this->NumInstanceFields() << " entries):\n";
319       if (h_this->IsResolved()) {
320         for (size_t i = 0; i < h_this->NumInstanceFields(); ++i) {
321           os << StringPrintf("    %2zd: %s\n", i,
322                              ArtField::PrettyField(h_this->GetInstanceField(i)).c_str());
323         }
324       } else {
325         os << "    <not yet available>";
326       }
327     }
328   }
329 }
330 
SetReferenceInstanceOffsets(uint32_t new_reference_offsets)331 void Class::SetReferenceInstanceOffsets(uint32_t new_reference_offsets) {
332   if (kIsDebugBuild && new_reference_offsets != kClassWalkSuper) {
333     // Sanity check that the number of bits set in the reference offset bitmap
334     // agrees with the number of references
335     uint32_t count = 0;
336     for (ObjPtr<Class> c = this; c != nullptr; c = c->GetSuperClass()) {
337       count += c->NumReferenceInstanceFieldsDuringLinking();
338     }
339     // +1 for the Class in Object.
340     CHECK_EQ(static_cast<uint32_t>(POPCOUNT(new_reference_offsets)) + 1, count);
341   }
342   // Not called within a transaction.
343   SetField32<false>(OFFSET_OF_OBJECT_MEMBER(Class, reference_instance_offsets_),
344                     new_reference_offsets);
345 }
346 
IsInSamePackage(const StringPiece & descriptor1,const StringPiece & descriptor2)347 bool Class::IsInSamePackage(const StringPiece& descriptor1, const StringPiece& descriptor2) {
348   size_t i = 0;
349   size_t min_length = std::min(descriptor1.size(), descriptor2.size());
350   while (i < min_length && descriptor1[i] == descriptor2[i]) {
351     ++i;
352   }
353   if (descriptor1.find('/', i) != StringPiece::npos ||
354       descriptor2.find('/', i) != StringPiece::npos) {
355     return false;
356   } else {
357     return true;
358   }
359 }
360 
IsInSamePackage(ObjPtr<Class> that)361 bool Class::IsInSamePackage(ObjPtr<Class> that) {
362   ObjPtr<Class> klass1 = this;
363   ObjPtr<Class> klass2 = that;
364   if (klass1 == klass2) {
365     return true;
366   }
367   // Class loaders must match.
368   if (klass1->GetClassLoader() != klass2->GetClassLoader()) {
369     return false;
370   }
371   // Arrays are in the same package when their element classes are.
372   while (klass1->IsArrayClass()) {
373     klass1 = klass1->GetComponentType();
374   }
375   while (klass2->IsArrayClass()) {
376     klass2 = klass2->GetComponentType();
377   }
378   // trivial check again for array types
379   if (klass1 == klass2) {
380     return true;
381   }
382   // Compare the package part of the descriptor string.
383   std::string temp1, temp2;
384   return IsInSamePackage(klass1->GetDescriptor(&temp1), klass2->GetDescriptor(&temp2));
385 }
386 
IsThrowableClass()387 bool Class::IsThrowableClass() {
388   return WellKnownClasses::ToClass(WellKnownClasses::java_lang_Throwable)->IsAssignableFrom(this);
389 }
390 
SetClassLoader(ObjPtr<ClassLoader> new_class_loader)391 void Class::SetClassLoader(ObjPtr<ClassLoader> new_class_loader) {
392   if (Runtime::Current()->IsActiveTransaction()) {
393     SetFieldObject<true>(OFFSET_OF_OBJECT_MEMBER(Class, class_loader_), new_class_loader);
394   } else {
395     SetFieldObject<false>(OFFSET_OF_OBJECT_MEMBER(Class, class_loader_), new_class_loader);
396   }
397 }
398 
399 template <typename SignatureType>
FindInterfaceMethodWithSignature(ObjPtr<Class> klass,const StringPiece & name,const SignatureType & signature,PointerSize pointer_size)400 static inline ArtMethod* FindInterfaceMethodWithSignature(ObjPtr<Class> klass,
401                                                           const StringPiece& name,
402                                                           const SignatureType& signature,
403                                                           PointerSize pointer_size)
404     REQUIRES_SHARED(Locks::mutator_lock_) {
405   // If the current class is not an interface, skip the search of its declared methods;
406   // such lookup is used only to distinguish between IncompatibleClassChangeError and
407   // NoSuchMethodError and the caller has already tried to search methods in the class.
408   if (LIKELY(klass->IsInterface())) {
409     // Search declared methods, both direct and virtual.
410     // (This lookup is used also for invoke-static on interface classes.)
411     for (ArtMethod& method : klass->GetDeclaredMethodsSlice(pointer_size)) {
412       if (method.GetName() == name && method.GetSignature() == signature) {
413         return &method;
414       }
415     }
416   }
417 
418   // TODO: If there is a unique maximally-specific non-abstract superinterface method,
419   // we should return it, otherwise an arbitrary one can be returned.
420   ObjPtr<IfTable> iftable = klass->GetIfTable();
421   for (int32_t i = 0, iftable_count = iftable->Count(); i < iftable_count; ++i) {
422     ObjPtr<Class> iface = iftable->GetInterface(i);
423     for (ArtMethod& method : iface->GetVirtualMethodsSlice(pointer_size)) {
424       if (method.GetName() == name && method.GetSignature() == signature) {
425         return &method;
426       }
427     }
428   }
429 
430   // Then search for public non-static methods in the java.lang.Object.
431   if (LIKELY(klass->IsInterface())) {
432     ObjPtr<Class> object_class = klass->GetSuperClass();
433     DCHECK(object_class->IsObjectClass());
434     for (ArtMethod& method : object_class->GetDeclaredMethodsSlice(pointer_size)) {
435       if (method.IsPublic() && !method.IsStatic() &&
436           method.GetName() == name && method.GetSignature() == signature) {
437         return &method;
438       }
439     }
440   }
441   return nullptr;
442 }
443 
FindInterfaceMethod(const StringPiece & name,const StringPiece & signature,PointerSize pointer_size)444 ArtMethod* Class::FindInterfaceMethod(const StringPiece& name,
445                                       const StringPiece& signature,
446                                       PointerSize pointer_size) {
447   return FindInterfaceMethodWithSignature(this, name, signature, pointer_size);
448 }
449 
FindInterfaceMethod(const StringPiece & name,const Signature & signature,PointerSize pointer_size)450 ArtMethod* Class::FindInterfaceMethod(const StringPiece& name,
451                                       const Signature& signature,
452                                       PointerSize pointer_size) {
453   return FindInterfaceMethodWithSignature(this, name, signature, pointer_size);
454 }
455 
FindInterfaceMethod(ObjPtr<DexCache> dex_cache,uint32_t dex_method_idx,PointerSize pointer_size)456 ArtMethod* Class::FindInterfaceMethod(ObjPtr<DexCache> dex_cache,
457                                       uint32_t dex_method_idx,
458                                       PointerSize pointer_size) {
459   // We always search by name and signature, ignoring the type index in the MethodId.
460   const DexFile& dex_file = *dex_cache->GetDexFile();
461   const DexFile::MethodId& method_id = dex_file.GetMethodId(dex_method_idx);
462   StringPiece name = dex_file.StringDataByIdx(method_id.name_idx_);
463   const Signature signature = dex_file.GetMethodSignature(method_id);
464   return FindInterfaceMethod(name, signature, pointer_size);
465 }
466 
IsValidInheritanceCheck(ObjPtr<mirror::Class> klass,ObjPtr<mirror::Class> declaring_class)467 static inline bool IsValidInheritanceCheck(ObjPtr<mirror::Class> klass,
468                                            ObjPtr<mirror::Class> declaring_class)
469     REQUIRES_SHARED(Locks::mutator_lock_) {
470   if (klass->IsArrayClass()) {
471     return declaring_class->IsObjectClass();
472   } else if (klass->IsInterface()) {
473     return declaring_class->IsObjectClass() || declaring_class == klass;
474   } else {
475     return klass->IsSubClass(declaring_class);
476   }
477 }
478 
IsInheritedMethod(ObjPtr<mirror::Class> klass,ObjPtr<mirror::Class> declaring_class,ArtMethod & method)479 static inline bool IsInheritedMethod(ObjPtr<mirror::Class> klass,
480                                      ObjPtr<mirror::Class> declaring_class,
481                                      ArtMethod& method)
482     REQUIRES_SHARED(Locks::mutator_lock_) {
483   DCHECK_EQ(declaring_class, method.GetDeclaringClass());
484   DCHECK_NE(klass, declaring_class);
485   DCHECK(IsValidInheritanceCheck(klass, declaring_class));
486   uint32_t access_flags = method.GetAccessFlags();
487   if ((access_flags & (kAccPublic | kAccProtected)) != 0) {
488     return true;
489   }
490   if ((access_flags & kAccPrivate) != 0) {
491     return false;
492   }
493   for (; klass != declaring_class; klass = klass->GetSuperClass()) {
494     if (!klass->IsInSamePackage(declaring_class)) {
495       return false;
496     }
497   }
498   return true;
499 }
500 
501 template <typename SignatureType>
FindClassMethodWithSignature(ObjPtr<Class> this_klass,const StringPiece & name,const SignatureType & signature,PointerSize pointer_size)502 static inline ArtMethod* FindClassMethodWithSignature(ObjPtr<Class> this_klass,
503                                                       const StringPiece& name,
504                                                       const SignatureType& signature,
505                                                       PointerSize pointer_size)
506     REQUIRES_SHARED(Locks::mutator_lock_) {
507   // Search declared methods first.
508   for (ArtMethod& method : this_klass->GetDeclaredMethodsSlice(pointer_size)) {
509     ArtMethod* np_method = method.GetInterfaceMethodIfProxy(pointer_size);
510     if (np_method->GetName() == name && np_method->GetSignature() == signature) {
511       return &method;
512     }
513   }
514 
515   // Then search the superclass chain. If we find an inherited method, return it.
516   // If we find a method that's not inherited because of access restrictions,
517   // try to find a method inherited from an interface in copied methods.
518   ObjPtr<Class> klass = this_klass->GetSuperClass();
519   ArtMethod* uninherited_method = nullptr;
520   for (; klass != nullptr; klass = klass->GetSuperClass()) {
521     DCHECK(!klass->IsProxyClass());
522     for (ArtMethod& method : klass->GetDeclaredMethodsSlice(pointer_size)) {
523       if (method.GetName() == name && method.GetSignature() == signature) {
524         if (IsInheritedMethod(this_klass, klass, method)) {
525           return &method;
526         }
527         uninherited_method = &method;
528         break;
529       }
530     }
531     if (uninherited_method != nullptr) {
532       break;
533     }
534   }
535 
536   // Then search copied methods.
537   // If we found a method that's not inherited, stop the search in its declaring class.
538   ObjPtr<Class> end_klass = klass;
539   DCHECK_EQ(uninherited_method != nullptr, end_klass != nullptr);
540   klass = this_klass;
541   if (UNLIKELY(klass->IsProxyClass())) {
542     DCHECK(klass->GetCopiedMethodsSlice(pointer_size).empty());
543     klass = klass->GetSuperClass();
544   }
545   for (; klass != end_klass; klass = klass->GetSuperClass()) {
546     DCHECK(!klass->IsProxyClass());
547     for (ArtMethod& method : klass->GetCopiedMethodsSlice(pointer_size)) {
548       if (method.GetName() == name && method.GetSignature() == signature) {
549         return &method;  // No further check needed, copied methods are inherited by definition.
550       }
551     }
552   }
553   return uninherited_method;  // Return the `uninherited_method` if any.
554 }
555 
556 
FindClassMethod(const StringPiece & name,const StringPiece & signature,PointerSize pointer_size)557 ArtMethod* Class::FindClassMethod(const StringPiece& name,
558                                   const StringPiece& signature,
559                                   PointerSize pointer_size) {
560   return FindClassMethodWithSignature(this, name, signature, pointer_size);
561 }
562 
FindClassMethod(const StringPiece & name,const Signature & signature,PointerSize pointer_size)563 ArtMethod* Class::FindClassMethod(const StringPiece& name,
564                                   const Signature& signature,
565                                   PointerSize pointer_size) {
566   return FindClassMethodWithSignature(this, name, signature, pointer_size);
567 }
568 
FindClassMethod(ObjPtr<DexCache> dex_cache,uint32_t dex_method_idx,PointerSize pointer_size)569 ArtMethod* Class::FindClassMethod(ObjPtr<DexCache> dex_cache,
570                                   uint32_t dex_method_idx,
571                                   PointerSize pointer_size) {
572   // FIXME: Hijacking a proxy class by a custom class loader can break this assumption.
573   DCHECK(!IsProxyClass());
574 
575   // First try to find a declared method by dex_method_idx if we have a dex_cache match.
576   ObjPtr<DexCache> this_dex_cache = GetDexCache();
577   if (this_dex_cache == dex_cache) {
578     // Lookup is always performed in the class referenced by the MethodId.
579     DCHECK_EQ(dex_type_idx_, GetDexFile().GetMethodId(dex_method_idx).class_idx_.index_);
580     for (ArtMethod& method : GetDeclaredMethodsSlice(pointer_size)) {
581       if (method.GetDexMethodIndex() == dex_method_idx) {
582         return &method;
583       }
584     }
585   }
586   // If not found, we need to search by name and signature.
587   const DexFile& dex_file = *dex_cache->GetDexFile();
588   const DexFile::MethodId& method_id = dex_file.GetMethodId(dex_method_idx);
589   const Signature signature = dex_file.GetMethodSignature(method_id);
590   StringPiece name;  // Delay strlen() until actually needed.
591   // If we do not have a dex_cache match, try to find the declared method in this class now.
592   if (this_dex_cache != dex_cache && !GetDeclaredMethodsSlice(pointer_size).empty()) {
593     DCHECK(name.empty());
594     name = dex_file.StringDataByIdx(method_id.name_idx_);
595     for (ArtMethod& method : GetDeclaredMethodsSlice(pointer_size)) {
596       if (method.GetName() == name && method.GetSignature() == signature) {
597         return &method;
598       }
599     }
600   }
601 
602   // Then search the superclass chain. If we find an inherited method, return it.
603   // If we find a method that's not inherited because of access restrictions,
604   // try to find a method inherited from an interface in copied methods.
605   ArtMethod* uninherited_method = nullptr;
606   ObjPtr<Class> klass = GetSuperClass();
607   for (; klass != nullptr; klass = klass->GetSuperClass()) {
608     ArtMethod* candidate_method = nullptr;
609     ArraySlice<ArtMethod> declared_methods = klass->GetDeclaredMethodsSlice(pointer_size);
610     if (klass->GetDexCache() == dex_cache) {
611       // Matching dex_cache. We cannot compare the `dex_method_idx` anymore because
612       // the type index differs, so compare the name index and proto index.
613       for (ArtMethod& method : declared_methods) {
614         const DexFile::MethodId& cmp_method_id = dex_file.GetMethodId(method.GetDexMethodIndex());
615         if (cmp_method_id.name_idx_ == method_id.name_idx_ &&
616             cmp_method_id.proto_idx_ == method_id.proto_idx_) {
617           candidate_method = &method;
618           break;
619         }
620       }
621     } else {
622       if (!declared_methods.empty() && name.empty()) {
623         name = dex_file.StringDataByIdx(method_id.name_idx_);
624       }
625       for (ArtMethod& method : declared_methods) {
626         if (method.GetName() == name && method.GetSignature() == signature) {
627           candidate_method = &method;
628           break;
629         }
630       }
631     }
632     if (candidate_method != nullptr) {
633       if (IsInheritedMethod(this, klass, *candidate_method)) {
634         return candidate_method;
635       } else {
636         uninherited_method = candidate_method;
637         break;
638       }
639     }
640   }
641 
642   // Then search copied methods.
643   // If we found a method that's not inherited, stop the search in its declaring class.
644   ObjPtr<Class> end_klass = klass;
645   DCHECK_EQ(uninherited_method != nullptr, end_klass != nullptr);
646   // After we have searched the declared methods of the super-class chain,
647   // search copied methods which can contain methods from interfaces.
648   for (klass = this; klass != end_klass; klass = klass->GetSuperClass()) {
649     ArraySlice<ArtMethod> copied_methods = klass->GetCopiedMethodsSlice(pointer_size);
650     if (!copied_methods.empty() && name.empty()) {
651       name = dex_file.StringDataByIdx(method_id.name_idx_);
652     }
653     for (ArtMethod& method : copied_methods) {
654       if (method.GetName() == name && method.GetSignature() == signature) {
655         return &method;  // No further check needed, copied methods are inherited by definition.
656       }
657     }
658   }
659   return uninherited_method;  // Return the `uninherited_method` if any.
660 }
661 
FindConstructor(const StringPiece & signature,PointerSize pointer_size)662 ArtMethod* Class::FindConstructor(const StringPiece& signature, PointerSize pointer_size) {
663   // Internal helper, never called on proxy classes. We can skip GetInterfaceMethodIfProxy().
664   DCHECK(!IsProxyClass());
665   StringPiece name("<init>");
666   for (ArtMethod& method : GetDirectMethodsSliceUnchecked(pointer_size)) {
667     if (method.GetName() == name && method.GetSignature() == signature) {
668       return &method;
669     }
670   }
671   return nullptr;
672 }
673 
FindDeclaredDirectMethodByName(const StringPiece & name,PointerSize pointer_size)674 ArtMethod* Class::FindDeclaredDirectMethodByName(const StringPiece& name,
675                                                  PointerSize pointer_size) {
676   for (auto& method : GetDirectMethods(pointer_size)) {
677     ArtMethod* const np_method = method.GetInterfaceMethodIfProxy(pointer_size);
678     if (name == np_method->GetName()) {
679       return &method;
680     }
681   }
682   return nullptr;
683 }
684 
FindDeclaredVirtualMethodByName(const StringPiece & name,PointerSize pointer_size)685 ArtMethod* Class::FindDeclaredVirtualMethodByName(const StringPiece& name,
686                                                   PointerSize pointer_size) {
687   for (auto& method : GetVirtualMethods(pointer_size)) {
688     ArtMethod* const np_method = method.GetInterfaceMethodIfProxy(pointer_size);
689     if (name == np_method->GetName()) {
690       return &method;
691     }
692   }
693   return nullptr;
694 }
695 
FindVirtualMethodForInterfaceSuper(ArtMethod * method,PointerSize pointer_size)696 ArtMethod* Class::FindVirtualMethodForInterfaceSuper(ArtMethod* method, PointerSize pointer_size) {
697   DCHECK(method->GetDeclaringClass()->IsInterface());
698   DCHECK(IsInterface()) << "Should only be called on a interface class";
699   // Check if we have one defined on this interface first. This includes searching copied ones to
700   // get any conflict methods. Conflict methods are copied into each subtype from the supertype. We
701   // don't do any indirect method checks here.
702   for (ArtMethod& iface_method : GetVirtualMethods(pointer_size)) {
703     if (method->HasSameNameAndSignature(&iface_method)) {
704       return &iface_method;
705     }
706   }
707 
708   std::vector<ArtMethod*> abstract_methods;
709   // Search through the IFTable for a working version. We don't need to check for conflicts
710   // because if there was one it would appear in this classes virtual_methods_ above.
711 
712   Thread* self = Thread::Current();
713   StackHandleScope<2> hs(self);
714   MutableHandle<IfTable> iftable(hs.NewHandle(GetIfTable()));
715   MutableHandle<Class> iface(hs.NewHandle<Class>(nullptr));
716   size_t iftable_count = GetIfTableCount();
717   // Find the method. We don't need to check for conflicts because they would have been in the
718   // copied virtuals of this interface.  Order matters, traverse in reverse topological order; most
719   // subtypiest interfaces get visited first.
720   for (size_t k = iftable_count; k != 0;) {
721     k--;
722     DCHECK_LT(k, iftable->Count());
723     iface.Assign(iftable->GetInterface(k));
724     // Iterate through every declared method on this interface. Each direct method's name/signature
725     // is unique so the order of the inner loop doesn't matter.
726     for (auto& method_iter : iface->GetDeclaredVirtualMethods(pointer_size)) {
727       ArtMethod* current_method = &method_iter;
728       if (current_method->HasSameNameAndSignature(method)) {
729         if (current_method->IsDefault()) {
730           // Handle JLS soft errors, a default method from another superinterface tree can
731           // "override" an abstract method(s) from another superinterface tree(s).  To do this,
732           // ignore any [default] method which are dominated by the abstract methods we've seen so
733           // far. Check if overridden by any in abstract_methods. We do not need to check for
734           // default_conflicts because we would hit those before we get to this loop.
735           bool overridden = false;
736           for (ArtMethod* possible_override : abstract_methods) {
737             DCHECK(possible_override->HasSameNameAndSignature(current_method));
738             if (iface->IsAssignableFrom(possible_override->GetDeclaringClass())) {
739               overridden = true;
740               break;
741             }
742           }
743           if (!overridden) {
744             return current_method;
745           }
746         } else {
747           // Is not default.
748           // This might override another default method. Just stash it for now.
749           abstract_methods.push_back(current_method);
750         }
751       }
752     }
753   }
754   // If we reach here we either never found any declaration of the method (in which case
755   // 'abstract_methods' is empty or we found no non-overriden default methods in which case
756   // 'abstract_methods' contains a number of abstract implementations of the methods. We choose one
757   // of these arbitrarily.
758   return abstract_methods.empty() ? nullptr : abstract_methods[0];
759 }
760 
FindClassInitializer(PointerSize pointer_size)761 ArtMethod* Class::FindClassInitializer(PointerSize pointer_size) {
762   for (ArtMethod& method : GetDirectMethods(pointer_size)) {
763     if (method.IsClassInitializer()) {
764       DCHECK_STREQ(method.GetName(), "<clinit>");
765       DCHECK_STREQ(method.GetSignature().ToString().c_str(), "()V");
766       return &method;
767     }
768   }
769   return nullptr;
770 }
771 
772 // Custom binary search to avoid double comparisons from std::binary_search.
FindFieldByNameAndType(LengthPrefixedArray<ArtField> * fields,const StringPiece & name,const StringPiece & type)773 static ArtField* FindFieldByNameAndType(LengthPrefixedArray<ArtField>* fields,
774                                         const StringPiece& name,
775                                         const StringPiece& type)
776     REQUIRES_SHARED(Locks::mutator_lock_) {
777   if (fields == nullptr) {
778     return nullptr;
779   }
780   size_t low = 0;
781   size_t high = fields->size();
782   ArtField* ret = nullptr;
783   while (low < high) {
784     size_t mid = (low + high) / 2;
785     ArtField& field = fields->At(mid);
786     // Fields are sorted by class, then name, then type descriptor. This is verified in dex file
787     // verifier. There can be multiple fields with the same in the same class name due to proguard.
788     int result = StringPiece(field.GetName()).Compare(name);
789     if (result == 0) {
790       result = StringPiece(field.GetTypeDescriptor()).Compare(type);
791     }
792     if (result < 0) {
793       low = mid + 1;
794     } else if (result > 0) {
795       high = mid;
796     } else {
797       ret = &field;
798       break;
799     }
800   }
801   if (kIsDebugBuild) {
802     ArtField* found = nullptr;
803     for (ArtField& field : MakeIterationRangeFromLengthPrefixedArray(fields)) {
804       if (name == field.GetName() && type == field.GetTypeDescriptor()) {
805         found = &field;
806         break;
807       }
808     }
809     CHECK_EQ(found, ret) << "Found " << found->PrettyField() << " vs  " << ret->PrettyField();
810   }
811   return ret;
812 }
813 
FindDeclaredInstanceField(const StringPiece & name,const StringPiece & type)814 ArtField* Class::FindDeclaredInstanceField(const StringPiece& name, const StringPiece& type) {
815   // Binary search by name. Interfaces are not relevant because they can't contain instance fields.
816   return FindFieldByNameAndType(GetIFieldsPtr(), name, type);
817 }
818 
FindDeclaredInstanceField(ObjPtr<DexCache> dex_cache,uint32_t dex_field_idx)819 ArtField* Class::FindDeclaredInstanceField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx) {
820   if (GetDexCache() == dex_cache) {
821     for (ArtField& field : GetIFields()) {
822       if (field.GetDexFieldIndex() == dex_field_idx) {
823         return &field;
824       }
825     }
826   }
827   return nullptr;
828 }
829 
FindInstanceField(const StringPiece & name,const StringPiece & type)830 ArtField* Class::FindInstanceField(const StringPiece& name, const StringPiece& type) {
831   // Is the field in this class, or any of its superclasses?
832   // Interfaces are not relevant because they can't contain instance fields.
833   for (ObjPtr<Class> c = this; c != nullptr; c = c->GetSuperClass()) {
834     ArtField* f = c->FindDeclaredInstanceField(name, type);
835     if (f != nullptr) {
836       return f;
837     }
838   }
839   return nullptr;
840 }
841 
FindInstanceField(ObjPtr<DexCache> dex_cache,uint32_t dex_field_idx)842 ArtField* Class::FindInstanceField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx) {
843   // Is the field in this class, or any of its superclasses?
844   // Interfaces are not relevant because they can't contain instance fields.
845   for (ObjPtr<Class> c = this; c != nullptr; c = c->GetSuperClass()) {
846     ArtField* f = c->FindDeclaredInstanceField(dex_cache, dex_field_idx);
847     if (f != nullptr) {
848       return f;
849     }
850   }
851   return nullptr;
852 }
853 
FindDeclaredStaticField(const StringPiece & name,const StringPiece & type)854 ArtField* Class::FindDeclaredStaticField(const StringPiece& name, const StringPiece& type) {
855   DCHECK(type != nullptr);
856   return FindFieldByNameAndType(GetSFieldsPtr(), name, type);
857 }
858 
FindDeclaredStaticField(ObjPtr<DexCache> dex_cache,uint32_t dex_field_idx)859 ArtField* Class::FindDeclaredStaticField(ObjPtr<DexCache> dex_cache, uint32_t dex_field_idx) {
860   if (dex_cache == GetDexCache()) {
861     for (ArtField& field : GetSFields()) {
862       if (field.GetDexFieldIndex() == dex_field_idx) {
863         return &field;
864       }
865     }
866   }
867   return nullptr;
868 }
869 
FindStaticField(Thread * self,ObjPtr<Class> klass,const StringPiece & name,const StringPiece & type)870 ArtField* Class::FindStaticField(Thread* self,
871                                  ObjPtr<Class> klass,
872                                  const StringPiece& name,
873                                  const StringPiece& type) {
874   // Is the field in this class (or its interfaces), or any of its
875   // superclasses (or their interfaces)?
876   for (ObjPtr<Class> k = klass; k != nullptr; k = k->GetSuperClass()) {
877     // Is the field in this class?
878     ArtField* f = k->FindDeclaredStaticField(name, type);
879     if (f != nullptr) {
880       return f;
881     }
882     // Is this field in any of this class' interfaces?
883     for (uint32_t i = 0, num_interfaces = k->NumDirectInterfaces(); i != num_interfaces; ++i) {
884       ObjPtr<Class> interface = GetDirectInterface(self, k, i);
885       DCHECK(interface != nullptr);
886       f = FindStaticField(self, interface, name, type);
887       if (f != nullptr) {
888         return f;
889       }
890     }
891   }
892   return nullptr;
893 }
894 
FindStaticField(Thread * self,ObjPtr<Class> klass,ObjPtr<DexCache> dex_cache,uint32_t dex_field_idx)895 ArtField* Class::FindStaticField(Thread* self,
896                                  ObjPtr<Class> klass,
897                                  ObjPtr<DexCache> dex_cache,
898                                  uint32_t dex_field_idx) {
899   for (ObjPtr<Class> k = klass; k != nullptr; k = k->GetSuperClass()) {
900     // Is the field in this class?
901     ArtField* f = k->FindDeclaredStaticField(dex_cache, dex_field_idx);
902     if (f != nullptr) {
903       return f;
904     }
905     // Though GetDirectInterface() should not cause thread suspension when called
906     // from here, it takes a Handle as an argument, so we need to wrap `k`.
907     ScopedAssertNoThreadSuspension ants(__FUNCTION__);
908     // Is this field in any of this class' interfaces?
909     for (uint32_t i = 0, num_interfaces = k->NumDirectInterfaces(); i != num_interfaces; ++i) {
910       ObjPtr<Class> interface = GetDirectInterface(self, k, i);
911       DCHECK(interface != nullptr);
912       f = FindStaticField(self, interface, dex_cache, dex_field_idx);
913       if (f != nullptr) {
914         return f;
915       }
916     }
917   }
918   return nullptr;
919 }
920 
FindField(Thread * self,ObjPtr<Class> klass,const StringPiece & name,const StringPiece & type)921 ArtField* Class::FindField(Thread* self,
922                            ObjPtr<Class> klass,
923                            const StringPiece& name,
924                            const StringPiece& type) {
925   // Find a field using the JLS field resolution order
926   for (ObjPtr<Class> k = klass; k != nullptr; k = k->GetSuperClass()) {
927     // Is the field in this class?
928     ArtField* f = k->FindDeclaredInstanceField(name, type);
929     if (f != nullptr) {
930       return f;
931     }
932     f = k->FindDeclaredStaticField(name, type);
933     if (f != nullptr) {
934       return f;
935     }
936     // Is this field in any of this class' interfaces?
937     for (uint32_t i = 0, num_interfaces = k->NumDirectInterfaces(); i != num_interfaces; ++i) {
938       ObjPtr<Class> interface = GetDirectInterface(self, k, i);
939       DCHECK(interface != nullptr);
940       f = FindStaticField(self, interface, name, type);
941       if (f != nullptr) {
942         return f;
943       }
944     }
945   }
946   return nullptr;
947 }
948 
SetSkipAccessChecksFlagOnAllMethods(PointerSize pointer_size)949 void Class::SetSkipAccessChecksFlagOnAllMethods(PointerSize pointer_size) {
950   DCHECK(IsVerified());
951   for (auto& m : GetMethods(pointer_size)) {
952     if (!m.IsNative() && m.IsInvokable()) {
953       m.SetSkipAccessChecks();
954     }
955   }
956 }
957 
GetDescriptor(std::string * storage)958 const char* Class::GetDescriptor(std::string* storage) {
959   if (IsPrimitive()) {
960     return Primitive::Descriptor(GetPrimitiveType());
961   } else if (IsArrayClass()) {
962     return GetArrayDescriptor(storage);
963   } else if (IsProxyClass()) {
964     *storage = Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(this);
965     return storage->c_str();
966   } else {
967     const DexFile& dex_file = GetDexFile();
968     const DexFile::TypeId& type_id = dex_file.GetTypeId(GetClassDef()->class_idx_);
969     return dex_file.GetTypeDescriptor(type_id);
970   }
971 }
972 
GetArrayDescriptor(std::string * storage)973 const char* Class::GetArrayDescriptor(std::string* storage) {
974   std::string temp;
975   const char* elem_desc = GetComponentType()->GetDescriptor(&temp);
976   *storage = "[";
977   *storage += elem_desc;
978   return storage->c_str();
979 }
980 
GetClassDef()981 const DexFile::ClassDef* Class::GetClassDef() {
982   uint16_t class_def_idx = GetDexClassDefIndex();
983   if (class_def_idx == DexFile::kDexNoIndex16) {
984     return nullptr;
985   }
986   return &GetDexFile().GetClassDef(class_def_idx);
987 }
988 
GetDirectInterfaceTypeIdx(uint32_t idx)989 dex::TypeIndex Class::GetDirectInterfaceTypeIdx(uint32_t idx) {
990   DCHECK(!IsPrimitive());
991   DCHECK(!IsArrayClass());
992   return GetInterfaceTypeList()->GetTypeItem(idx).type_idx_;
993 }
994 
GetDirectInterface(Thread * self,ObjPtr<Class> klass,uint32_t idx)995 ObjPtr<Class> Class::GetDirectInterface(Thread* self, ObjPtr<Class> klass, uint32_t idx) {
996   DCHECK(klass != nullptr);
997   DCHECK(!klass->IsPrimitive());
998   if (klass->IsArrayClass()) {
999     ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
1000     // Use ClassLinker::LookupClass(); avoid poisoning ObjPtr<>s by ClassLinker::FindSystemClass().
1001     ObjPtr<Class> interface;
1002     if (idx == 0) {
1003       interface = class_linker->LookupClass(self, "Ljava/lang/Cloneable;", nullptr);
1004     } else {
1005       DCHECK_EQ(1U, idx);
1006       interface = class_linker->LookupClass(self, "Ljava/io/Serializable;", nullptr);
1007     }
1008     DCHECK(interface != nullptr);
1009     return interface;
1010   } else if (klass->IsProxyClass()) {
1011     ObjPtr<ObjectArray<Class>> interfaces = klass->GetProxyInterfaces();
1012     DCHECK(interfaces != nullptr);
1013     return interfaces->Get(idx);
1014   } else {
1015     dex::TypeIndex type_idx = klass->GetDirectInterfaceTypeIdx(idx);
1016     ObjPtr<Class> interface = ClassLinker::LookupResolvedType(
1017         type_idx, klass->GetDexCache(), klass->GetClassLoader());
1018     return interface;
1019   }
1020 }
1021 
ResolveDirectInterface(Thread * self,Handle<Class> klass,uint32_t idx)1022 ObjPtr<Class> Class::ResolveDirectInterface(Thread* self, Handle<Class> klass, uint32_t idx) {
1023   ObjPtr<Class> interface = GetDirectInterface(self, klass.Get(), idx);
1024   if (interface == nullptr) {
1025     DCHECK(!klass->IsArrayClass());
1026     DCHECK(!klass->IsProxyClass());
1027     dex::TypeIndex type_idx = klass->GetDirectInterfaceTypeIdx(idx);
1028     interface = Runtime::Current()->GetClassLinker()->ResolveType(klass->GetDexFile(),
1029                                                                   type_idx,
1030                                                                   klass.Get());
1031     CHECK(interface != nullptr || self->IsExceptionPending());
1032   }
1033   return interface;
1034 }
1035 
GetCommonSuperClass(Handle<Class> klass)1036 ObjPtr<Class> Class::GetCommonSuperClass(Handle<Class> klass) {
1037   DCHECK(klass != nullptr);
1038   DCHECK(!klass->IsInterface());
1039   DCHECK(!IsInterface());
1040   ObjPtr<Class> common_super_class = this;
1041   while (!common_super_class->IsAssignableFrom(klass.Get())) {
1042     ObjPtr<Class> old_common = common_super_class;
1043     common_super_class = old_common->GetSuperClass();
1044     DCHECK(common_super_class != nullptr) << old_common->PrettyClass();
1045   }
1046   return common_super_class;
1047 }
1048 
GetSourceFile()1049 const char* Class::GetSourceFile() {
1050   const DexFile& dex_file = GetDexFile();
1051   const DexFile::ClassDef* dex_class_def = GetClassDef();
1052   if (dex_class_def == nullptr) {
1053     // Generated classes have no class def.
1054     return nullptr;
1055   }
1056   return dex_file.GetSourceFile(*dex_class_def);
1057 }
1058 
GetLocation()1059 std::string Class::GetLocation() {
1060   ObjPtr<DexCache> dex_cache = GetDexCache();
1061   if (dex_cache != nullptr && !IsProxyClass()) {
1062     return dex_cache->GetLocation()->ToModifiedUtf8();
1063   }
1064   // Arrays and proxies are generated and have no corresponding dex file location.
1065   return "generated class";
1066 }
1067 
GetInterfaceTypeList()1068 const DexFile::TypeList* Class::GetInterfaceTypeList() {
1069   const DexFile::ClassDef* class_def = GetClassDef();
1070   if (class_def == nullptr) {
1071     return nullptr;
1072   }
1073   return GetDexFile().GetInterfacesList(*class_def);
1074 }
1075 
PopulateEmbeddedVTable(PointerSize pointer_size)1076 void Class::PopulateEmbeddedVTable(PointerSize pointer_size) {
1077   PointerArray* table = GetVTableDuringLinking();
1078   CHECK(table != nullptr) << PrettyClass();
1079   const size_t table_length = table->GetLength();
1080   SetEmbeddedVTableLength(table_length);
1081   for (size_t i = 0; i < table_length; i++) {
1082     SetEmbeddedVTableEntry(i, table->GetElementPtrSize<ArtMethod*>(i, pointer_size), pointer_size);
1083   }
1084   // Keep java.lang.Object class's vtable around for since it's easier
1085   // to be reused by array classes during their linking.
1086   if (!IsObjectClass()) {
1087     SetVTable(nullptr);
1088   }
1089 }
1090 
1091 class ReadBarrierOnNativeRootsVisitor {
1092  public:
operator ()(ObjPtr<Object> obj ATTRIBUTE_UNUSED,MemberOffset offset ATTRIBUTE_UNUSED,bool is_static ATTRIBUTE_UNUSED) const1093   void operator()(ObjPtr<Object> obj ATTRIBUTE_UNUSED,
1094                   MemberOffset offset ATTRIBUTE_UNUSED,
1095                   bool is_static ATTRIBUTE_UNUSED) const {}
1096 
VisitRootIfNonNull(CompressedReference<Object> * root) const1097   void VisitRootIfNonNull(CompressedReference<Object>* root) const
1098       REQUIRES_SHARED(Locks::mutator_lock_) {
1099     if (!root->IsNull()) {
1100       VisitRoot(root);
1101     }
1102   }
1103 
VisitRoot(CompressedReference<Object> * root) const1104   void VisitRoot(CompressedReference<Object>* root) const
1105       REQUIRES_SHARED(Locks::mutator_lock_) {
1106     ObjPtr<Object> old_ref = root->AsMirrorPtr();
1107     ObjPtr<Object> new_ref = ReadBarrier::BarrierForRoot(root);
1108     if (old_ref != new_ref) {
1109       // Update the field atomically. This may fail if mutator updates before us, but it's ok.
1110       auto* atomic_root =
1111           reinterpret_cast<Atomic<CompressedReference<Object>>*>(root);
1112       atomic_root->CompareExchangeStrongSequentiallyConsistent(
1113           CompressedReference<Object>::FromMirrorPtr(old_ref.Ptr()),
1114           CompressedReference<Object>::FromMirrorPtr(new_ref.Ptr()));
1115     }
1116   }
1117 };
1118 
1119 // The pre-fence visitor for Class::CopyOf().
1120 class CopyClassVisitor {
1121  public:
CopyClassVisitor(Thread * self,Handle<Class> * orig,size_t new_length,size_t copy_bytes,ImTable * imt,PointerSize pointer_size)1122   CopyClassVisitor(Thread* self,
1123                    Handle<Class>* orig,
1124                    size_t new_length,
1125                    size_t copy_bytes,
1126                    ImTable* imt,
1127                    PointerSize pointer_size)
1128       : self_(self), orig_(orig), new_length_(new_length),
1129         copy_bytes_(copy_bytes), imt_(imt), pointer_size_(pointer_size) {
1130   }
1131 
operator ()(ObjPtr<Object> obj,size_t usable_size ATTRIBUTE_UNUSED) const1132   void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
1133       REQUIRES_SHARED(Locks::mutator_lock_) {
1134     StackHandleScope<1> hs(self_);
1135     Handle<mirror::Class> h_new_class_obj(hs.NewHandle(obj->AsClass()));
1136     Object::CopyObject(h_new_class_obj.Get(), orig_->Get(), copy_bytes_);
1137     Class::SetStatus(h_new_class_obj, Class::kStatusResolving, self_);
1138     h_new_class_obj->PopulateEmbeddedVTable(pointer_size_);
1139     h_new_class_obj->SetImt(imt_, pointer_size_);
1140     h_new_class_obj->SetClassSize(new_length_);
1141     // Visit all of the references to make sure there is no from space references in the native
1142     // roots.
1143     ObjPtr<Object>(h_new_class_obj.Get())->VisitReferences(
1144         ReadBarrierOnNativeRootsVisitor(), VoidFunctor());
1145   }
1146 
1147  private:
1148   Thread* const self_;
1149   Handle<Class>* const orig_;
1150   const size_t new_length_;
1151   const size_t copy_bytes_;
1152   ImTable* imt_;
1153   const PointerSize pointer_size_;
1154   DISALLOW_COPY_AND_ASSIGN(CopyClassVisitor);
1155 };
1156 
CopyOf(Thread * self,int32_t new_length,ImTable * imt,PointerSize pointer_size)1157 Class* Class::CopyOf(Thread* self, int32_t new_length, ImTable* imt, PointerSize pointer_size) {
1158   DCHECK_GE(new_length, static_cast<int32_t>(sizeof(Class)));
1159   // We may get copied by a compacting GC.
1160   StackHandleScope<1> hs(self);
1161   Handle<Class> h_this(hs.NewHandle(this));
1162   gc::Heap* heap = Runtime::Current()->GetHeap();
1163   // The num_bytes (3rd param) is sizeof(Class) as opposed to SizeOf()
1164   // to skip copying the tail part that we will overwrite here.
1165   CopyClassVisitor visitor(self, &h_this, new_length, sizeof(Class), imt, pointer_size);
1166   ObjPtr<Object> new_class = kMovingClasses ?
1167       heap->AllocObject<true>(self, java_lang_Class_.Read(), new_length, visitor) :
1168       heap->AllocNonMovableObject<true>(self, java_lang_Class_.Read(), new_length, visitor);
1169   if (UNLIKELY(new_class == nullptr)) {
1170     self->AssertPendingOOMException();
1171     return nullptr;
1172   }
1173   return new_class->AsClass();
1174 }
1175 
ProxyDescriptorEquals(const char * match)1176 bool Class::ProxyDescriptorEquals(const char* match) {
1177   DCHECK(IsProxyClass());
1178   return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(this) == match;
1179 }
1180 
1181 // TODO: Move this to java_lang_Class.cc?
GetDeclaredConstructor(Thread * self,Handle<ObjectArray<Class>> args,PointerSize pointer_size)1182 ArtMethod* Class::GetDeclaredConstructor(
1183     Thread* self, Handle<ObjectArray<Class>> args, PointerSize pointer_size) {
1184   for (auto& m : GetDirectMethods(pointer_size)) {
1185     // Skip <clinit> which is a static constructor, as well as non constructors.
1186     if (m.IsStatic() || !m.IsConstructor()) {
1187       continue;
1188     }
1189     // May cause thread suspension and exceptions.
1190     if (m.GetInterfaceMethodIfProxy(kRuntimePointerSize)->EqualParameters(args)) {
1191       return &m;
1192     }
1193     if (UNLIKELY(self->IsExceptionPending())) {
1194       return nullptr;
1195     }
1196   }
1197   return nullptr;
1198 }
1199 
Depth()1200 uint32_t Class::Depth() {
1201   uint32_t depth = 0;
1202   for (ObjPtr<Class> klass = this; klass->GetSuperClass() != nullptr; klass = klass->GetSuperClass()) {
1203     depth++;
1204   }
1205   return depth;
1206 }
1207 
FindTypeIndexInOtherDexFile(const DexFile & dex_file)1208 dex::TypeIndex Class::FindTypeIndexInOtherDexFile(const DexFile& dex_file) {
1209   std::string temp;
1210   const DexFile::TypeId* type_id = dex_file.FindTypeId(GetDescriptor(&temp));
1211   return (type_id == nullptr) ? dex::TypeIndex() : dex_file.GetIndexForTypeId(*type_id);
1212 }
1213 
1214 template <PointerSize kPointerSize, bool kTransactionActive>
GetDeclaredMethodInternal(Thread * self,ObjPtr<Class> klass,ObjPtr<String> name,ObjPtr<ObjectArray<Class>> args)1215 ObjPtr<Method> Class::GetDeclaredMethodInternal(
1216     Thread* self,
1217     ObjPtr<Class> klass,
1218     ObjPtr<String> name,
1219     ObjPtr<ObjectArray<Class>> args) {
1220   // Covariant return types permit the class to define multiple
1221   // methods with the same name and parameter types. Prefer to
1222   // return a non-synthetic method in such situations. We may
1223   // still return a synthetic method to handle situations like
1224   // escalated visibility. We never return miranda methods that
1225   // were synthesized by the runtime.
1226   constexpr uint32_t kSkipModifiers = kAccMiranda | kAccSynthetic;
1227   StackHandleScope<3> hs(self);
1228   auto h_method_name = hs.NewHandle(name);
1229   if (UNLIKELY(h_method_name == nullptr)) {
1230     ThrowNullPointerException("name == null");
1231     return nullptr;
1232   }
1233   auto h_args = hs.NewHandle(args);
1234   Handle<Class> h_klass = hs.NewHandle(klass);
1235   ArtMethod* result = nullptr;
1236   for (auto& m : h_klass->GetDeclaredVirtualMethods(kPointerSize)) {
1237     auto* np_method = m.GetInterfaceMethodIfProxy(kPointerSize);
1238     // May cause thread suspension.
1239     ObjPtr<String> np_name = np_method->GetNameAsString(self);
1240     if (!np_name->Equals(h_method_name.Get()) || !np_method->EqualParameters(h_args)) {
1241       if (UNLIKELY(self->IsExceptionPending())) {
1242         return nullptr;
1243       }
1244       continue;
1245     }
1246     auto modifiers = m.GetAccessFlags();
1247     if ((modifiers & kSkipModifiers) == 0) {
1248       return Method::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, &m);
1249     }
1250     if ((modifiers & kAccMiranda) == 0) {
1251       result = &m;  // Remember as potential result if it's not a miranda method.
1252     }
1253   }
1254   if (result == nullptr) {
1255     for (auto& m : h_klass->GetDirectMethods(kPointerSize)) {
1256       auto modifiers = m.GetAccessFlags();
1257       if ((modifiers & kAccConstructor) != 0) {
1258         continue;
1259       }
1260       auto* np_method = m.GetInterfaceMethodIfProxy(kPointerSize);
1261       // May cause thread suspension.
1262       ObjPtr<String> np_name = np_method->GetNameAsString(self);
1263       if (np_name == nullptr) {
1264         self->AssertPendingException();
1265         return nullptr;
1266       }
1267       if (!np_name->Equals(h_method_name.Get()) || !np_method->EqualParameters(h_args)) {
1268         if (UNLIKELY(self->IsExceptionPending())) {
1269           return nullptr;
1270         }
1271         continue;
1272       }
1273       if ((modifiers & kSkipModifiers) == 0) {
1274         return Method::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, &m);
1275       }
1276       // Direct methods cannot be miranda methods, so this potential result must be synthetic.
1277       result = &m;
1278     }
1279   }
1280   return result != nullptr
1281       ? Method::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, result)
1282       : nullptr;
1283 }
1284 
1285 template
1286 ObjPtr<Method> Class::GetDeclaredMethodInternal<PointerSize::k32, false>(
1287     Thread* self,
1288     ObjPtr<Class> klass,
1289     ObjPtr<String> name,
1290     ObjPtr<ObjectArray<Class>> args);
1291 template
1292 ObjPtr<Method> Class::GetDeclaredMethodInternal<PointerSize::k32, true>(
1293     Thread* self,
1294     ObjPtr<Class> klass,
1295     ObjPtr<String> name,
1296     ObjPtr<ObjectArray<Class>> args);
1297 template
1298 ObjPtr<Method> Class::GetDeclaredMethodInternal<PointerSize::k64, false>(
1299     Thread* self,
1300     ObjPtr<Class> klass,
1301     ObjPtr<String> name,
1302     ObjPtr<ObjectArray<Class>> args);
1303 template
1304 ObjPtr<Method> Class::GetDeclaredMethodInternal<PointerSize::k64, true>(
1305     Thread* self,
1306     ObjPtr<Class> klass,
1307     ObjPtr<String> name,
1308     ObjPtr<ObjectArray<Class>> args);
1309 
1310 template <PointerSize kPointerSize, bool kTransactionActive>
GetDeclaredConstructorInternal(Thread * self,ObjPtr<Class> klass,ObjPtr<ObjectArray<Class>> args)1311 ObjPtr<Constructor> Class::GetDeclaredConstructorInternal(
1312     Thread* self,
1313     ObjPtr<Class> klass,
1314     ObjPtr<ObjectArray<Class>> args) {
1315   StackHandleScope<1> hs(self);
1316   ArtMethod* result = klass->GetDeclaredConstructor(self, hs.NewHandle(args), kPointerSize);
1317   return result != nullptr
1318       ? Constructor::CreateFromArtMethod<kPointerSize, kTransactionActive>(self, result)
1319       : nullptr;
1320 }
1321 
1322 // Constructor::CreateFromArtMethod<kTransactionActive>(self, result)
1323 
1324 template
1325 ObjPtr<Constructor> Class::GetDeclaredConstructorInternal<PointerSize::k32, false>(
1326     Thread* self,
1327     ObjPtr<Class> klass,
1328     ObjPtr<ObjectArray<Class>> args);
1329 template
1330 ObjPtr<Constructor> Class::GetDeclaredConstructorInternal<PointerSize::k32, true>(
1331     Thread* self,
1332     ObjPtr<Class> klass,
1333     ObjPtr<ObjectArray<Class>> args);
1334 template
1335 ObjPtr<Constructor> Class::GetDeclaredConstructorInternal<PointerSize::k64, false>(
1336     Thread* self,
1337     ObjPtr<Class> klass,
1338     ObjPtr<ObjectArray<Class>> args);
1339 template
1340 ObjPtr<Constructor> Class::GetDeclaredConstructorInternal<PointerSize::k64, true>(
1341     Thread* self,
1342     ObjPtr<Class> klass,
1343     ObjPtr<ObjectArray<Class>> args);
1344 
GetInnerClassFlags(Handle<Class> h_this,int32_t default_value)1345 int32_t Class::GetInnerClassFlags(Handle<Class> h_this, int32_t default_value) {
1346   if (h_this->IsProxyClass() || h_this->GetDexCache() == nullptr) {
1347     return default_value;
1348   }
1349   uint32_t flags;
1350   if (!annotations::GetInnerClassFlags(h_this, &flags)) {
1351     return default_value;
1352   }
1353   return flags;
1354 }
1355 
SetObjectSizeAllocFastPath(uint32_t new_object_size)1356 void Class::SetObjectSizeAllocFastPath(uint32_t new_object_size) {
1357   if (Runtime::Current()->IsActiveTransaction()) {
1358     SetField32Volatile<true>(ObjectSizeAllocFastPathOffset(), new_object_size);
1359   } else {
1360     SetField32Volatile<false>(ObjectSizeAllocFastPathOffset(), new_object_size);
1361   }
1362 }
1363 
PrettyDescriptor(ObjPtr<mirror::Class> klass)1364 std::string Class::PrettyDescriptor(ObjPtr<mirror::Class> klass) {
1365   if (klass == nullptr) {
1366     return "null";
1367   }
1368   return klass->PrettyDescriptor();
1369 }
1370 
PrettyDescriptor()1371 std::string Class::PrettyDescriptor() {
1372   std::string temp;
1373   return art::PrettyDescriptor(GetDescriptor(&temp));
1374 }
1375 
PrettyClass(ObjPtr<mirror::Class> c)1376 std::string Class::PrettyClass(ObjPtr<mirror::Class> c) {
1377   if (c == nullptr) {
1378     return "null";
1379   }
1380   return c->PrettyClass();
1381 }
1382 
PrettyClass()1383 std::string Class::PrettyClass() {
1384   std::string result;
1385   result += "java.lang.Class<";
1386   result += PrettyDescriptor();
1387   result += ">";
1388   return result;
1389 }
1390 
PrettyClassAndClassLoader(ObjPtr<mirror::Class> c)1391 std::string Class::PrettyClassAndClassLoader(ObjPtr<mirror::Class> c) {
1392   if (c == nullptr) {
1393     return "null";
1394   }
1395   return c->PrettyClassAndClassLoader();
1396 }
1397 
PrettyClassAndClassLoader()1398 std::string Class::PrettyClassAndClassLoader() {
1399   std::string result;
1400   result += "java.lang.Class<";
1401   result += PrettyDescriptor();
1402   result += ",";
1403   result += mirror::Object::PrettyTypeOf(GetClassLoader());
1404   // TODO: add an identifying hash value for the loader
1405   result += ">";
1406   return result;
1407 }
1408 
GetAccessFlagsDCheck()1409 template<VerifyObjectFlags kVerifyFlags> void Class::GetAccessFlagsDCheck() {
1410   // Check class is loaded/retired or this is java.lang.String that has a
1411   // circularity issue during loading the names of its members
1412   DCHECK(IsIdxLoaded<kVerifyFlags>() || IsRetired<kVerifyFlags>() ||
1413          IsErroneous<static_cast<VerifyObjectFlags>(kVerifyFlags & ~kVerifyThis)>() ||
1414          this == String::GetJavaLangString())
1415               << "IsIdxLoaded=" << IsIdxLoaded<kVerifyFlags>()
1416               << " IsRetired=" << IsRetired<kVerifyFlags>()
1417               << " IsErroneous=" <<
1418               IsErroneous<static_cast<VerifyObjectFlags>(kVerifyFlags & ~kVerifyThis)>()
1419               << " IsString=" << (this == String::GetJavaLangString())
1420               << " status= " << GetStatus<kVerifyFlags>()
1421               << " descriptor=" << PrettyDescriptor();
1422 }
1423 // Instantiate the common cases.
1424 template void Class::GetAccessFlagsDCheck<kVerifyNone>();
1425 template void Class::GetAccessFlagsDCheck<kVerifyThis>();
1426 template void Class::GetAccessFlagsDCheck<kVerifyReads>();
1427 template void Class::GetAccessFlagsDCheck<kVerifyWrites>();
1428 template void Class::GetAccessFlagsDCheck<kVerifyAll>();
1429 
1430 }  // namespace mirror
1431 }  // namespace art
1432