/* * Copyright (c) 1999, 2018, 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. * */ #ifndef SHARE_VM_CI_CIOBJECT_HPP #define SHARE_VM_CI_CIOBJECT_HPP #include "ci/ciBaseObject.hpp" #include "ci/ciClassList.hpp" #include "runtime/handles.hpp" #include "runtime/jniHandles.hpp" // 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 friend class 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; protected: ciObject(); ciObject(oop o); ciObject(Handle h); ciObject(ciKlass* klass); jobject handle() const { return _handle; } // Get the VM oop that this object holds. oop get_oop() const; void init_flags_from(oop x); // Virtual behavior of the print() method. virtual void print_impl(outputStream* st) {} virtual const char* type_string() { return "ciObject"; } 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 has an encoding as a constant. // True if is_perm is true. // Also true if ScavengeRootsInCode is non-zero. // If it does not have an encoding, the compiler is responsible for // making other arrangements for dealing with the oop. // See ciEnv::make_array bool can_be_constant(); // Tells if this oop should be made a constant. // True if is_perm is true or ScavengeRootsInCode > 1. bool should_be_constant(); // Might this object possibly move during a scavenge operation? // If the answer is true and ScavengeRootsInCode==0, the oop cannot be embedded in code. bool is_scavengable() { return (_ident & SCAVENGABLE_FLAG) != 0; } // 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(); virtual bool is_object() const { return true; } // What kind of ciObject is this? virtual bool is_null_object() const { return false; } virtual bool is_call_site() const { return false; } virtual bool is_cpcache() const { return false; } virtual bool is_instance() { return false; } virtual bool is_member_name() const { return false; } virtual bool is_method_handle() const { return false; } virtual bool is_method_type() const { return false; } virtual bool is_array() { return false; } virtual bool is_obj_array() { return false; } virtual bool is_type_array() { return false; } // Is this a type or value which has no associated class? // It is true of primitive types and null objects. virtual bool is_classless() const { return false; } virtual void 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(); } // Subclass casting with assertions. ciNullObject* as_null_object() { assert(is_null_object(), "bad cast"); return (ciNullObject*)this; } ciCallSite* as_call_site() { assert(is_call_site(), "bad cast"); return (ciCallSite*)this; } ciInstance* as_instance() { assert(is_instance(), "bad cast"); return (ciInstance*)this; } ciMemberName* as_member_name() { assert(is_member_name(), "bad cast"); return (ciMemberName*)this; } ciMethodHandle* as_method_handle() { assert(is_method_handle(), "bad cast"); return (ciMethodHandle*)this; } ciMethodType* as_method_type() { assert(is_method_type(), "bad cast"); return (ciMethodType*)this; } ciArray* as_array() { assert(is_array(), "bad cast"); return (ciArray*)this; } ciObjArray* as_obj_array() { assert(is_obj_array(), "bad cast"); return (ciObjArray*)this; } ciTypeArray* as_type_array() { assert(is_type_array(), "bad cast"); return (ciTypeArray*)this; } // Print debugging output about this ciObject. void print(outputStream* st); void print() { print(tty); } // GDB cannot handle default arguments // Print debugging output about the oop this ciObject represents. void print_oop(outputStream* st = tty); }; #endif // SHARE_VM_CI_CIOBJECT_HPP