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 #ifndef ART_RUNTIME_CLASS_STATUS_H_ 18 #define ART_RUNTIME_CLASS_STATUS_H_ 19 20 #include <iosfwd> 21 #include <stdint.h> 22 23 namespace art { 24 25 // Class Status 26 // 27 // kRetired: Class that's temporarily used till class linking time 28 // has its (vtable) size figured out and has been cloned to one with the 29 // right size which will be the one used later. The old one is retired and 30 // will be gc'ed once all refs to the class point to the newly 31 // cloned version. 32 // 33 // kErrorUnresolved, kErrorResolved: Class is erroneous. We need 34 // to distinguish between classes that have been resolved and classes that 35 // have not. This is important because the const-class instruction needs to 36 // return a previously resolved class even if its subsequent initialization 37 // failed. We also need this to decide whether to wrap a previous 38 // initialization failure in ClassDefNotFound error or not. 39 // 40 // kNotReady: If a Class cannot be found in the class table by 41 // FindClass, it allocates an new one with AllocClass in the 42 // kNotReady and calls LoadClass. Note if it does find a 43 // class, it may not be kResolved and it will try to push it 44 // forward toward kResolved. 45 // 46 // kIdx: LoadClass populates with Class with information from 47 // the DexFile, moving the status to kIdx, indicating that the 48 // Class value in super_class_ has not been populated. The new Class 49 // can then be inserted into the classes table. 50 // 51 // kLoaded: After taking a lock on Class, the ClassLinker will 52 // attempt to move a kIdx class forward to kLoaded by 53 // using ResolveClass to initialize the super_class_ and ensuring the 54 // interfaces are resolved. 55 // 56 // kResolving: Class is just cloned with the right size from 57 // temporary class that's acting as a placeholder for linking. The old 58 // class will be retired. New class is set to this status first before 59 // moving on to being resolved. 60 // 61 // kResolved: Still holding the lock on Class, the ClassLinker 62 // shows linking is complete and fields of the Class populated by making 63 // it kResolved. Java allows circularities of the form where a super 64 // class has a field that is of the type of the sub class. We need to be able 65 // to fully resolve super classes while resolving types for fields. 66 // 67 // kRetryVerificationAtRuntime: The verifier sets a class to 68 // this state if it encounters a soft failure at compile time. This 69 // often happens when there are unresolved classes in other dex 70 // files, and this status marks a class as needing to be verified 71 // again at runtime. This status is only set and seen during AOT 72 // compilation, and the compiler will mark the class as resolved in the 73 // image and/or oat file. 74 // 75 // kVerifiedNeedsAccessChecks: The verifier sets a class to 76 // this state if it encounters access-checks only soft failure at compile 77 // time. This happens when there are unresolved classes in other dex 78 // files, and this status marks a class as verified but that will need to run 79 // with access checks enabled in the interpreter. 80 // 81 // TODO: Explain the other states 82 enum class ClassStatus : uint8_t { 83 kNotReady = 0, // Zero-initialized Class object starts in this state. 84 kRetired = 1, // Retired, should not be used. Use the newly cloned one instead. 85 kErrorResolved = 2, 86 kErrorUnresolved = 3, 87 kIdx = 4, // Loaded, DEX idx in super_class_type_idx_ and interfaces_type_idx_. 88 kLoaded = 5, // DEX idx values resolved. 89 kResolving = 6, // Just cloned from temporary class object. 90 kResolved = 7, // Part of linking. 91 kVerifying = 8, // In the process of being verified. 92 kRetryVerificationAtRuntime = 9, // Compile time verification failed, retry at runtime. 93 kVerifiedNeedsAccessChecks = 10, // Compile time verification only failed for access checks. 94 kVerified = 11, // Logically part of linking; done pre-init. 95 kSuperclassValidated = 12, // Superclass validation part of init done. 96 kInitializing = 13, // Class init in progress. 97 kInitialized = 14, // Ready to go. 98 kVisiblyInitialized = 15, // Initialized and visible to all threads. 99 kLast = kVisiblyInitialized 100 }; 101 102 std::ostream& operator<<(std::ostream& os, const ClassStatus& rhs); 103 104 } // namespace art 105 106 #endif // ART_RUNTIME_CLASS_STATUS_H_ 107