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      1 /*
      2  * Copyright (C) 2008 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 <limits.h>
     18 
     19 #include "ScopedUtfChars.h"
     20 #include "class_linker-inl.h"
     21 #include "common_throws.h"
     22 #include "debugger.h"
     23 #include "dex_file-inl.h"
     24 #include "gc/accounting/card_table-inl.h"
     25 #include "gc/allocator/dlmalloc.h"
     26 #include "gc/heap.h"
     27 #include "gc/space/dlmalloc_space.h"
     28 #include "gc/space/image_space.h"
     29 #include "instruction_set.h"
     30 #include "intern_table.h"
     31 #include "jni_internal.h"
     32 #include "mirror/art_method-inl.h"
     33 #include "mirror/class-inl.h"
     34 #include "mirror/dex_cache-inl.h"
     35 #include "mirror/object-inl.h"
     36 #include "runtime.h"
     37 #include "scoped_fast_native_object_access.h"
     38 #include "scoped_thread_state_change.h"
     39 #include "thread.h"
     40 #include "thread_list.h"
     41 #include "toStringArray.h"
     42 
     43 namespace art {
     44 
     45 static jfloat VMRuntime_getTargetHeapUtilization(JNIEnv*, jobject) {
     46   return Runtime::Current()->GetHeap()->GetTargetHeapUtilization();
     47 }
     48 
     49 static void VMRuntime_nativeSetTargetHeapUtilization(JNIEnv*, jobject, jfloat target) {
     50   Runtime::Current()->GetHeap()->SetTargetHeapUtilization(target);
     51 }
     52 
     53 static void VMRuntime_startJitCompilation(JNIEnv*, jobject) {
     54 }
     55 
     56 static void VMRuntime_disableJitCompilation(JNIEnv*, jobject) {
     57 }
     58 
     59 static jobject VMRuntime_newNonMovableArray(JNIEnv* env, jobject, jclass javaElementClass,
     60                                             jint length) {
     61   ScopedFastNativeObjectAccess soa(env);
     62   if (UNLIKELY(length < 0)) {
     63     ThrowNegativeArraySizeException(length);
     64     return nullptr;
     65   }
     66   mirror::Class* element_class = soa.Decode<mirror::Class*>(javaElementClass);
     67   if (UNLIKELY(element_class == nullptr)) {
     68     ThrowNullPointerException(NULL, "element class == null");
     69     return nullptr;
     70   }
     71   Runtime* runtime = Runtime::Current();
     72   mirror::Class* array_class =
     73       runtime->GetClassLinker()->FindArrayClass(soa.Self(), &element_class);
     74   if (UNLIKELY(array_class == nullptr)) {
     75     return nullptr;
     76   }
     77   gc::AllocatorType allocator = runtime->GetHeap()->GetCurrentNonMovingAllocator();
     78   mirror::Array* result = mirror::Array::Alloc<true>(soa.Self(), array_class, length,
     79                                                      array_class->GetComponentSize(), allocator);
     80   return soa.AddLocalReference<jobject>(result);
     81 }
     82 
     83 static jobject VMRuntime_newUnpaddedArray(JNIEnv* env, jobject, jclass javaElementClass,
     84                                           jint length) {
     85   ScopedFastNativeObjectAccess soa(env);
     86   if (UNLIKELY(length < 0)) {
     87     ThrowNegativeArraySizeException(length);
     88     return nullptr;
     89   }
     90   mirror::Class* element_class = soa.Decode<mirror::Class*>(javaElementClass);
     91   if (UNLIKELY(element_class == nullptr)) {
     92     ThrowNullPointerException(NULL, "element class == null");
     93     return nullptr;
     94   }
     95   Runtime* runtime = Runtime::Current();
     96   mirror::Class* array_class = runtime->GetClassLinker()->FindArrayClass(soa.Self(),
     97                                                                          &element_class);
     98   if (UNLIKELY(array_class == nullptr)) {
     99     return nullptr;
    100   }
    101   gc::AllocatorType allocator = runtime->GetHeap()->GetCurrentAllocator();
    102   mirror::Array* result = mirror::Array::Alloc<true>(soa.Self(), array_class, length,
    103                                                      array_class->GetComponentSize(), allocator,
    104                                                      true);
    105   return soa.AddLocalReference<jobject>(result);
    106 }
    107 
    108 static jlong VMRuntime_addressOf(JNIEnv* env, jobject, jobject javaArray) {
    109   if (javaArray == NULL) {  // Most likely allocation failed
    110     return 0;
    111   }
    112   ScopedFastNativeObjectAccess soa(env);
    113   mirror::Array* array = soa.Decode<mirror::Array*>(javaArray);
    114   if (!array->IsArrayInstance()) {
    115     ThrowIllegalArgumentException(NULL, "not an array");
    116     return 0;
    117   }
    118   if (Runtime::Current()->GetHeap()->IsMovableObject(array)) {
    119     ThrowRuntimeException("Trying to get address of movable array object");
    120     return 0;
    121   }
    122   return reinterpret_cast<uintptr_t>(array->GetRawData(array->GetClass()->GetComponentSize(), 0));
    123 }
    124 
    125 static void VMRuntime_clearGrowthLimit(JNIEnv*, jobject) {
    126   Runtime::Current()->GetHeap()->ClearGrowthLimit();
    127 }
    128 
    129 static jboolean VMRuntime_isDebuggerActive(JNIEnv*, jobject) {
    130   return Dbg::IsDebuggerActive();
    131 }
    132 
    133 static jobjectArray VMRuntime_properties(JNIEnv* env, jobject) {
    134   return toStringArray(env, Runtime::Current()->GetProperties());
    135 }
    136 
    137 // This is for backward compatibility with dalvik which returned the
    138 // meaningless "." when no boot classpath or classpath was
    139 // specified. Unfortunately, some tests were using java.class.path to
    140 // lookup relative file locations, so they are counting on this to be
    141 // ".", presumably some applications or libraries could have as well.
    142 static const char* DefaultToDot(const std::string& class_path) {
    143   return class_path.empty() ? "." : class_path.c_str();
    144 }
    145 
    146 static jstring VMRuntime_bootClassPath(JNIEnv* env, jobject) {
    147   return env->NewStringUTF(DefaultToDot(Runtime::Current()->GetBootClassPathString()));
    148 }
    149 
    150 static jstring VMRuntime_classPath(JNIEnv* env, jobject) {
    151   return env->NewStringUTF(DefaultToDot(Runtime::Current()->GetClassPathString()));
    152 }
    153 
    154 static jstring VMRuntime_vmVersion(JNIEnv* env, jobject) {
    155   return env->NewStringUTF(Runtime::GetVersion());
    156 }
    157 
    158 static jstring VMRuntime_vmLibrary(JNIEnv* env, jobject) {
    159   return env->NewStringUTF(kIsDebugBuild ? "libartd.so" : "libart.so");
    160 }
    161 
    162 static jstring VMRuntime_vmInstructionSet(JNIEnv* env, jobject) {
    163   InstructionSet isa = Runtime::Current()->GetInstructionSet();
    164   const char* isa_string = GetInstructionSetString(isa);
    165   return env->NewStringUTF(isa_string);
    166 }
    167 
    168 static jboolean VMRuntime_is64Bit(JNIEnv* env, jobject) {
    169   bool is64BitMode = (sizeof(void*) == sizeof(uint64_t));
    170   return is64BitMode ? JNI_TRUE : JNI_FALSE;
    171 }
    172 
    173 static jboolean VMRuntime_isCheckJniEnabled(JNIEnv* env, jobject) {
    174   return Runtime::Current()->GetJavaVM()->check_jni ? JNI_TRUE : JNI_FALSE;
    175 }
    176 
    177 static void VMRuntime_setTargetSdkVersionNative(JNIEnv*, jobject, jint target_sdk_version) {
    178   // This is the target SDK version of the app we're about to run. It is intended that this a place
    179   // where workarounds can be enabled.
    180   // Note that targetSdkVersion may be CUR_DEVELOPMENT (10000).
    181   // Note that targetSdkVersion may be 0, meaning "current".
    182   Runtime::Current()->SetTargetSdkVersion(target_sdk_version);
    183 }
    184 
    185 static void VMRuntime_registerNativeAllocation(JNIEnv* env, jobject, jint bytes) {
    186   if (UNLIKELY(bytes < 0)) {
    187     ScopedObjectAccess soa(env);
    188     ThrowRuntimeException("allocation size negative %d", bytes);
    189     return;
    190   }
    191   Runtime::Current()->GetHeap()->RegisterNativeAllocation(env, static_cast<size_t>(bytes));
    192 }
    193 
    194 static void VMRuntime_registerNativeFree(JNIEnv* env, jobject, jint bytes) {
    195   if (UNLIKELY(bytes < 0)) {
    196     ScopedObjectAccess soa(env);
    197     ThrowRuntimeException("allocation size negative %d", bytes);
    198     return;
    199   }
    200   Runtime::Current()->GetHeap()->RegisterNativeFree(env, static_cast<size_t>(bytes));
    201 }
    202 
    203 static void VMRuntime_updateProcessState(JNIEnv* env, jobject, jint process_state) {
    204   Runtime::Current()->GetHeap()->UpdateProcessState(static_cast<gc::ProcessState>(process_state));
    205   Runtime::Current()->UpdateProfilerState(process_state);
    206 }
    207 
    208 static void VMRuntime_trimHeap(JNIEnv*, jobject) {
    209   Runtime::Current()->GetHeap()->DoPendingTransitionOrTrim();
    210 }
    211 
    212 static void VMRuntime_concurrentGC(JNIEnv* env, jobject) {
    213   Runtime::Current()->GetHeap()->ConcurrentGC(ThreadForEnv(env));
    214 }
    215 
    216 typedef std::map<std::string, mirror::String*> StringTable;
    217 
    218 static void PreloadDexCachesStringsCallback(mirror::Object** root, void* arg,
    219                                             const RootInfo& /*root_info*/)
    220     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    221   StringTable& table = *reinterpret_cast<StringTable*>(arg);
    222   mirror::String* string = const_cast<mirror::Object*>(*root)->AsString();
    223   table[string->ToModifiedUtf8()] = string;
    224 }
    225 
    226 // Based on ClassLinker::ResolveString.
    227 static void PreloadDexCachesResolveString(Handle<mirror::DexCache> dex_cache, uint32_t string_idx,
    228                                           StringTable& strings)
    229     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    230   mirror::String* string = dex_cache->GetResolvedString(string_idx);
    231   if (string != NULL) {
    232     return;
    233   }
    234   const DexFile* dex_file = dex_cache->GetDexFile();
    235   const char* utf8 = dex_file->StringDataByIdx(string_idx);
    236   string = strings[utf8];
    237   if (string == NULL) {
    238     return;
    239   }
    240   // LOG(INFO) << "VMRuntime.preloadDexCaches resolved string=" << utf8;
    241   dex_cache->SetResolvedString(string_idx, string);
    242 }
    243 
    244 // Based on ClassLinker::ResolveType.
    245 static void PreloadDexCachesResolveType(mirror::DexCache* dex_cache, uint32_t type_idx)
    246     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    247   mirror::Class* klass = dex_cache->GetResolvedType(type_idx);
    248   if (klass != NULL) {
    249     return;
    250   }
    251   const DexFile* dex_file = dex_cache->GetDexFile();
    252   const char* class_name = dex_file->StringByTypeIdx(type_idx);
    253   ClassLinker* linker = Runtime::Current()->GetClassLinker();
    254   if (class_name[1] == '\0') {
    255     klass = linker->FindPrimitiveClass(class_name[0]);
    256   } else {
    257     klass = linker->LookupClass(class_name, ComputeModifiedUtf8Hash(class_name), NULL);
    258   }
    259   if (klass == NULL) {
    260     return;
    261   }
    262   // LOG(INFO) << "VMRuntime.preloadDexCaches resolved klass=" << class_name;
    263   dex_cache->SetResolvedType(type_idx, klass);
    264   // Skip uninitialized classes because filled static storage entry implies it is initialized.
    265   if (!klass->IsInitialized()) {
    266     // LOG(INFO) << "VMRuntime.preloadDexCaches uninitialized klass=" << class_name;
    267     return;
    268   }
    269   // LOG(INFO) << "VMRuntime.preloadDexCaches static storage klass=" << class_name;
    270 }
    271 
    272 // Based on ClassLinker::ResolveField.
    273 static void PreloadDexCachesResolveField(Handle<mirror::DexCache> dex_cache, uint32_t field_idx,
    274                                          bool is_static)
    275     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    276   mirror::ArtField* field = dex_cache->GetResolvedField(field_idx);
    277   if (field != NULL) {
    278     return;
    279   }
    280   const DexFile* dex_file = dex_cache->GetDexFile();
    281   const DexFile::FieldId& field_id = dex_file->GetFieldId(field_idx);
    282   Thread* const self = Thread::Current();
    283   StackHandleScope<1> hs(self);
    284   Handle<mirror::Class> klass(hs.NewHandle(dex_cache->GetResolvedType(field_id.class_idx_)));
    285   if (klass.Get() == NULL) {
    286     return;
    287   }
    288   if (is_static) {
    289     field = mirror::Class::FindStaticField(self, klass, dex_cache.Get(), field_idx);
    290   } else {
    291     field = klass->FindInstanceField(dex_cache.Get(), field_idx);
    292   }
    293   if (field == NULL) {
    294     return;
    295   }
    296   // LOG(INFO) << "VMRuntime.preloadDexCaches resolved field " << PrettyField(field);
    297   dex_cache->SetResolvedField(field_idx, field);
    298 }
    299 
    300 // Based on ClassLinker::ResolveMethod.
    301 static void PreloadDexCachesResolveMethod(Handle<mirror::DexCache> dex_cache, uint32_t method_idx,
    302                                           InvokeType invoke_type)
    303     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    304   mirror::ArtMethod* method = dex_cache->GetResolvedMethod(method_idx);
    305   if (method != NULL) {
    306     return;
    307   }
    308   const DexFile* dex_file = dex_cache->GetDexFile();
    309   const DexFile::MethodId& method_id = dex_file->GetMethodId(method_idx);
    310   mirror::Class* klass = dex_cache->GetResolvedType(method_id.class_idx_);
    311   if (klass == NULL) {
    312     return;
    313   }
    314   switch (invoke_type) {
    315     case kDirect:
    316     case kStatic:
    317       method = klass->FindDirectMethod(dex_cache.Get(), method_idx);
    318       break;
    319     case kInterface:
    320       method = klass->FindInterfaceMethod(dex_cache.Get(), method_idx);
    321       break;
    322     case kSuper:
    323     case kVirtual:
    324       method = klass->FindVirtualMethod(dex_cache.Get(), method_idx);
    325       break;
    326     default:
    327       LOG(FATAL) << "Unreachable - invocation type: " << invoke_type;
    328   }
    329   if (method == NULL) {
    330     return;
    331   }
    332   // LOG(INFO) << "VMRuntime.preloadDexCaches resolved method " << PrettyMethod(method);
    333   dex_cache->SetResolvedMethod(method_idx, method);
    334 }
    335 
    336 struct DexCacheStats {
    337     uint32_t num_strings;
    338     uint32_t num_types;
    339     uint32_t num_fields;
    340     uint32_t num_methods;
    341     DexCacheStats() : num_strings(0),
    342                       num_types(0),
    343                       num_fields(0),
    344                       num_methods(0) {}
    345 };
    346 
    347 static const bool kPreloadDexCachesEnabled = true;
    348 
    349 // Disabled because it takes a long time (extra half second) but
    350 // gives almost no benefit in terms of saving private dirty pages.
    351 static const bool kPreloadDexCachesStrings = false;
    352 
    353 static const bool kPreloadDexCachesTypes = true;
    354 static const bool kPreloadDexCachesFieldsAndMethods = true;
    355 
    356 static const bool kPreloadDexCachesCollectStats = true;
    357 
    358 static void PreloadDexCachesStatsTotal(DexCacheStats* total) {
    359   if (!kPreloadDexCachesCollectStats) {
    360     return;
    361   }
    362 
    363   ClassLinker* linker = Runtime::Current()->GetClassLinker();
    364   const std::vector<const DexFile*>& boot_class_path = linker->GetBootClassPath();
    365   for (size_t i = 0; i< boot_class_path.size(); i++) {
    366     const DexFile* dex_file = boot_class_path[i];
    367     CHECK(dex_file != NULL);
    368     total->num_strings += dex_file->NumStringIds();
    369     total->num_fields += dex_file->NumFieldIds();
    370     total->num_methods += dex_file->NumMethodIds();
    371     total->num_types += dex_file->NumTypeIds();
    372   }
    373 }
    374 
    375 static void PreloadDexCachesStatsFilled(DexCacheStats* filled)
    376     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
    377   if (!kPreloadDexCachesCollectStats) {
    378       return;
    379   }
    380   ClassLinker* linker = Runtime::Current()->GetClassLinker();
    381   const std::vector<const DexFile*>& boot_class_path = linker->GetBootClassPath();
    382   for (size_t i = 0; i< boot_class_path.size(); i++) {
    383     const DexFile* dex_file = boot_class_path[i];
    384     CHECK(dex_file != NULL);
    385     mirror::DexCache* dex_cache = linker->FindDexCache(*dex_file);
    386     for (size_t i = 0; i < dex_cache->NumStrings(); i++) {
    387       mirror::String* string = dex_cache->GetResolvedString(i);
    388       if (string != NULL) {
    389         filled->num_strings++;
    390       }
    391     }
    392     for (size_t i = 0; i < dex_cache->NumResolvedTypes(); i++) {
    393       mirror::Class* klass = dex_cache->GetResolvedType(i);
    394       if (klass != NULL) {
    395         filled->num_types++;
    396       }
    397     }
    398     for (size_t i = 0; i < dex_cache->NumResolvedFields(); i++) {
    399       mirror::ArtField* field = dex_cache->GetResolvedField(i);
    400       if (field != NULL) {
    401         filled->num_fields++;
    402       }
    403     }
    404     for (size_t i = 0; i < dex_cache->NumResolvedMethods(); i++) {
    405       mirror::ArtMethod* method = dex_cache->GetResolvedMethod(i);
    406       if (method != NULL) {
    407         filled->num_methods++;
    408       }
    409     }
    410   }
    411 }
    412 
    413 // TODO: http://b/11309598 This code was ported over based on the
    414 // Dalvik version. However, ART has similar code in other places such
    415 // as the CompilerDriver. This code could probably be refactored to
    416 // serve both uses.
    417 static void VMRuntime_preloadDexCaches(JNIEnv* env, jobject) {
    418   if (!kPreloadDexCachesEnabled) {
    419     return;
    420   }
    421 
    422   ScopedObjectAccess soa(env);
    423 
    424   DexCacheStats total;
    425   DexCacheStats before;
    426   if (kPreloadDexCachesCollectStats) {
    427     LOG(INFO) << "VMRuntime.preloadDexCaches starting";
    428     PreloadDexCachesStatsTotal(&total);
    429     PreloadDexCachesStatsFilled(&before);
    430   }
    431 
    432   Runtime* runtime = Runtime::Current();
    433   ClassLinker* linker = runtime->GetClassLinker();
    434   Thread* self = ThreadForEnv(env);
    435 
    436   // We use a std::map to avoid heap allocating StringObjects to lookup in gDvm.literalStrings
    437   StringTable strings;
    438   if (kPreloadDexCachesStrings) {
    439     runtime->GetInternTable()->VisitRoots(PreloadDexCachesStringsCallback, &strings,
    440                                           kVisitRootFlagAllRoots);
    441   }
    442 
    443   const std::vector<const DexFile*>& boot_class_path = linker->GetBootClassPath();
    444   for (size_t i = 0; i< boot_class_path.size(); i++) {
    445     const DexFile* dex_file = boot_class_path[i];
    446     CHECK(dex_file != NULL);
    447     StackHandleScope<1> hs(self);
    448     Handle<mirror::DexCache> dex_cache(hs.NewHandle(linker->FindDexCache(*dex_file)));
    449 
    450     if (kPreloadDexCachesStrings) {
    451       for (size_t i = 0; i < dex_cache->NumStrings(); i++) {
    452         PreloadDexCachesResolveString(dex_cache, i, strings);
    453       }
    454     }
    455 
    456     if (kPreloadDexCachesTypes) {
    457       for (size_t i = 0; i < dex_cache->NumResolvedTypes(); i++) {
    458         PreloadDexCachesResolveType(dex_cache.Get(), i);
    459       }
    460     }
    461 
    462     if (kPreloadDexCachesFieldsAndMethods) {
    463       for (size_t class_def_index = 0;
    464            class_def_index < dex_file->NumClassDefs();
    465            class_def_index++) {
    466         const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_index);
    467         const byte* class_data = dex_file->GetClassData(class_def);
    468         if (class_data == NULL) {
    469           continue;
    470         }
    471         ClassDataItemIterator it(*dex_file, class_data);
    472         for (; it.HasNextStaticField(); it.Next()) {
    473           uint32_t field_idx = it.GetMemberIndex();
    474           PreloadDexCachesResolveField(dex_cache, field_idx, true);
    475         }
    476         for (; it.HasNextInstanceField(); it.Next()) {
    477           uint32_t field_idx = it.GetMemberIndex();
    478           PreloadDexCachesResolveField(dex_cache, field_idx, false);
    479         }
    480         for (; it.HasNextDirectMethod(); it.Next()) {
    481           uint32_t method_idx = it.GetMemberIndex();
    482           InvokeType invoke_type = it.GetMethodInvokeType(class_def);
    483           PreloadDexCachesResolveMethod(dex_cache, method_idx, invoke_type);
    484         }
    485         for (; it.HasNextVirtualMethod(); it.Next()) {
    486           uint32_t method_idx = it.GetMemberIndex();
    487           InvokeType invoke_type = it.GetMethodInvokeType(class_def);
    488           PreloadDexCachesResolveMethod(dex_cache, method_idx, invoke_type);
    489         }
    490       }
    491     }
    492   }
    493 
    494   if (kPreloadDexCachesCollectStats) {
    495     DexCacheStats after;
    496     PreloadDexCachesStatsFilled(&after);
    497     LOG(INFO) << StringPrintf("VMRuntime.preloadDexCaches strings total=%d before=%d after=%d",
    498                               total.num_strings, before.num_strings, after.num_strings);
    499     LOG(INFO) << StringPrintf("VMRuntime.preloadDexCaches types total=%d before=%d after=%d",
    500                               total.num_types, before.num_types, after.num_types);
    501     LOG(INFO) << StringPrintf("VMRuntime.preloadDexCaches fields total=%d before=%d after=%d",
    502                               total.num_fields, before.num_fields, after.num_fields);
    503     LOG(INFO) << StringPrintf("VMRuntime.preloadDexCaches methods total=%d before=%d after=%d",
    504                               total.num_methods, before.num_methods, after.num_methods);
    505     LOG(INFO) << StringPrintf("VMRuntime.preloadDexCaches finished");
    506   }
    507 }
    508 
    509 
    510 /*
    511  * This is called by the framework when it knows the application directory and
    512  * process name.  We use this information to start up the sampling profiler for
    513  * for ART.
    514  */
    515 static void VMRuntime_registerAppInfo(JNIEnv* env, jclass, jstring pkgName,
    516                                       jstring appDir, jstring procName) {
    517   const char *pkgNameChars = env->GetStringUTFChars(pkgName, NULL);
    518   std::string profileFile = StringPrintf("/data/dalvik-cache/profiles/%s", pkgNameChars);
    519 
    520   Runtime::Current()->StartProfiler(profileFile.c_str());
    521 
    522   env->ReleaseStringUTFChars(pkgName, pkgNameChars);
    523 }
    524 
    525 static jboolean VMRuntime_isBootClassPathOnDisk(JNIEnv* env, jclass, jstring java_instruction_set) {
    526   ScopedUtfChars instruction_set(env, java_instruction_set);
    527   if (instruction_set.c_str() == nullptr) {
    528     return JNI_FALSE;
    529   }
    530   InstructionSet isa = GetInstructionSetFromString(instruction_set.c_str());
    531   if (isa == kNone) {
    532     ScopedLocalRef<jclass> iae(env, env->FindClass("java/lang/IllegalArgumentException"));
    533     std::string message(StringPrintf("Instruction set %s is invalid.", instruction_set.c_str()));
    534     env->ThrowNew(iae.get(), message.c_str());
    535     return JNI_FALSE;
    536   }
    537   std::string error_msg;
    538   std::unique_ptr<ImageHeader> image_header(gc::space::ImageSpace::ReadImageHeader(
    539       Runtime::Current()->GetImageLocation().c_str(), isa, &error_msg));
    540   return image_header.get() != nullptr;
    541 }
    542 
    543 static jstring VMRuntime_getCurrentInstructionSet(JNIEnv* env, jclass) {
    544   return env->NewStringUTF(GetInstructionSetString(kRuntimeISA));
    545 }
    546 
    547 static JNINativeMethod gMethods[] = {
    548   NATIVE_METHOD(VMRuntime, addressOf, "!(Ljava/lang/Object;)J"),
    549   NATIVE_METHOD(VMRuntime, bootClassPath, "()Ljava/lang/String;"),
    550   NATIVE_METHOD(VMRuntime, classPath, "()Ljava/lang/String;"),
    551   NATIVE_METHOD(VMRuntime, clearGrowthLimit, "()V"),
    552   NATIVE_METHOD(VMRuntime, concurrentGC, "()V"),
    553   NATIVE_METHOD(VMRuntime, disableJitCompilation, "()V"),
    554   NATIVE_METHOD(VMRuntime, getTargetHeapUtilization, "()F"),
    555   NATIVE_METHOD(VMRuntime, isDebuggerActive, "!()Z"),
    556   NATIVE_METHOD(VMRuntime, nativeSetTargetHeapUtilization, "(F)V"),
    557   NATIVE_METHOD(VMRuntime, newNonMovableArray, "!(Ljava/lang/Class;I)Ljava/lang/Object;"),
    558   NATIVE_METHOD(VMRuntime, newUnpaddedArray, "!(Ljava/lang/Class;I)Ljava/lang/Object;"),
    559   NATIVE_METHOD(VMRuntime, properties, "()[Ljava/lang/String;"),
    560   NATIVE_METHOD(VMRuntime, setTargetSdkVersionNative, "(I)V"),
    561   NATIVE_METHOD(VMRuntime, registerNativeAllocation, "(I)V"),
    562   NATIVE_METHOD(VMRuntime, registerNativeFree, "(I)V"),
    563   NATIVE_METHOD(VMRuntime, updateProcessState, "(I)V"),
    564   NATIVE_METHOD(VMRuntime, startJitCompilation, "()V"),
    565   NATIVE_METHOD(VMRuntime, trimHeap, "()V"),
    566   NATIVE_METHOD(VMRuntime, vmVersion, "()Ljava/lang/String;"),
    567   NATIVE_METHOD(VMRuntime, vmLibrary, "()Ljava/lang/String;"),
    568   NATIVE_METHOD(VMRuntime, vmInstructionSet, "()Ljava/lang/String;"),
    569   NATIVE_METHOD(VMRuntime, is64Bit, "!()Z"),
    570   NATIVE_METHOD(VMRuntime, isCheckJniEnabled, "!()Z"),
    571   NATIVE_METHOD(VMRuntime, preloadDexCaches, "()V"),
    572   NATIVE_METHOD(VMRuntime, registerAppInfo,
    573                 "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V"),
    574   NATIVE_METHOD(VMRuntime, isBootClassPathOnDisk, "(Ljava/lang/String;)Z"),
    575   NATIVE_METHOD(VMRuntime, getCurrentInstructionSet, "()Ljava/lang/String;"),
    576 };
    577 
    578 void register_dalvik_system_VMRuntime(JNIEnv* env) {
    579   REGISTER_NATIVE_METHODS("dalvik/system/VMRuntime");
    580 }
    581 
    582 }  // namespace art
    583