/* * Copyright (c) 1999, 2022, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. *
*/
// ciObject // // This class represents an oop in the HotSpot virtual machine. // Its subclasses are structured in a hierarchy which mirrors // an aggregate of the VM's oop and klass hierarchies (see // oopHierarchy.hpp). Each instance of ciObject holds a handle // to a corresponding oop on the VM side and provides routines // for accessing the information in its oop. By using the ciObject // hierarchy for accessing oops in the VM, the compiler ensures // that it is safe with respect to garbage collection; that is, // GC and compilation can proceed independently without // interference. // // Within the VM, the oop and klass hierarchies are separate. // The compiler interface does not preserve this separation -- // the distinction between `Klass*' and `Klass' are not // reflected in the interface and instead the Klass hierarchy // is directly modeled as the subclasses of ciKlass. class ciObject : public ciBaseObject {
CI_PACKAGE_ACCESS friendclass ciEnv;
private: // A JNI handle referring to an oop in the VM. This // handle may, in a small set of cases, correctly be NULL.
jobject _handle;
ciKlass* _klass;
public: // The klass of this ciObject.
ciKlass* klass();
// Are two ciObjects equal? bool equals(ciObject* obj);
// A hash value for the convenience of compilers. int hash();
// Tells if this oop should be made a constant. bool should_be_constant();
// The address which the compiler should embed into the // generated code to represent this oop. This address // is not the true address of the oop -- it will get patched // during nmethod creation. // // Usage note: no address arithmetic allowed. Oop must // be registered with the oopRecorder.
jobject constant_encoding();
// Is this a type or value which has no associated class? // It is true of primitive types and null objects. virtualbool is_classless() const { returnfalse; } virtualvoid dump_replay_data(outputStream* st) { /* do nothing */ }
// Note: some ciObjects refer to oops which have yet to be created. // We refer to these as "unloaded". Specifically, there are // unloaded instances of java.lang.Class, // java.lang.invoke.MethodHandle, and java.lang.invoke.MethodType. // By convention the ciNullObject is considered loaded, and // primitive types are considered loaded. bool is_loaded() const { return handle() != NULL || is_classless();
}
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