/* * Copyright 1999-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.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 `klassOop' and `Klass' are not // reflected in the interface and instead the Klass hierarchy // is directly modeled as the subclasses of ciKlass. class ciObject : public ResourceObj { 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; uint _ident; enum { FLAG_BITS = 2 }; enum { PERM_FLAG = 1, SCAVENGABLE_FLAG = 2 }; 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 { assert(_handle != NULL, "null oop"); return JNIHandles::resolve_non_null(_handle); } void init_flags_from(oop x) { int flags = 0; if (x != NULL) { if (x->is_perm()) flags |= PERM_FLAG; if (x->is_scavengable()) flags |= SCAVENGABLE_FLAG; } _ident |= flags; } // Virtual behavior of the print() method. virtual void print_impl(outputStream* st) {} virtual const char* type_string() { return "ciObject"; } void set_ident(uint id); public: // The klass of this ciObject. ciKlass* klass(); // A number unique to this object. uint ident(); // 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_scavengable is false. // 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_scavengable is false or ScavengeRootsInCode > 1. bool should_be_constant(); // Is this object guaranteed to be in the permanent part of the heap? // If so, CollectedHeap::can_elide_permanent_oop_store_barriers is relevant. // If the answer is false, no guarantees are made. bool is_perm() { return (_ident & PERM_FLAG) != 0; } // 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(); // What kind of ciObject is this? virtual bool is_null_object() const { return false; } virtual bool is_cpcache() const { return false; } virtual bool is_instance() { return false; } virtual bool is_method() { return false; } virtual bool is_method_data() { return false; } virtual bool is_array() { return false; } virtual bool is_obj_array() { return false; } virtual bool is_type_array() { return false; } virtual bool is_symbol() { return false; } virtual bool is_type() { return false; } virtual bool is_return_address() { return false; } virtual bool is_klass() { return false; } virtual bool is_instance_klass() { return false; } virtual bool is_method_klass() { return false; } virtual bool is_array_klass() { return false; } virtual bool is_obj_array_klass() { return false; } virtual bool is_type_array_klass() { return false; } virtual bool is_symbol_klass() { return false; } virtual bool is_klass_klass() { return false; } virtual bool is_instance_klass_klass() { return false; } virtual bool is_array_klass_klass() { return false; } virtual bool is_obj_array_klass_klass() { return false; } virtual bool is_type_array_klass_klass() { 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; } // Is this ciObject a Java Language Object? That is, // is the ciObject an instance or an array virtual bool is_java_object() { return false; } // Does this ciObject represent a Java Language class? // That is, is the ciObject an instanceKlass or arrayKlass? virtual bool is_java_klass() { return false; } // Is this ciObject the ciInstanceKlass representing // java.lang.Object()? virtual bool is_java_lang_Object() { return false; } // Does this ciObject refer to a real oop in the VM? // // Note: some ciObjects refer to oops which have yet to be // created. We refer to these as "unloaded". Specifically, // there are unloaded ciMethods, ciObjArrayKlasses, and // ciInstanceKlasses. 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; } ciCPCache* as_cpcache() { assert(is_cpcache(), "bad cast"); return (ciCPCache*) this; } ciInstance* as_instance() { assert(is_instance(), "bad cast"); return (ciInstance*)this; } ciMethod* as_method() { assert(is_method(), "bad cast"); return (ciMethod*)this; } ciMethodData* as_method_data() { assert(is_method_data(), "bad cast"); return (ciMethodData*)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; } ciSymbol* as_symbol() { assert(is_symbol(), "bad cast"); return (ciSymbol*)this; } ciType* as_type() { assert(is_type(), "bad cast"); return (ciType*)this; } ciReturnAddress* as_return_address() { assert(is_return_address(), "bad cast"); return (ciReturnAddress*)this; } ciKlass* as_klass() { assert(is_klass(), "bad cast"); return (ciKlass*)this; } ciInstanceKlass* as_instance_klass() { assert(is_instance_klass(), "bad cast"); return (ciInstanceKlass*)this; } ciMethodKlass* as_method_klass() { assert(is_method_klass(), "bad cast"); return (ciMethodKlass*)this; } ciArrayKlass* as_array_klass() { assert(is_array_klass(), "bad cast"); return (ciArrayKlass*)this; } ciObjArrayKlass* as_obj_array_klass() { assert(is_obj_array_klass(), "bad cast"); return (ciObjArrayKlass*)this; } ciTypeArrayKlass* as_type_array_klass() { assert(is_type_array_klass(), "bad cast"); return (ciTypeArrayKlass*)this; } ciSymbolKlass* as_symbol_klass() { assert(is_symbol_klass(), "bad cast"); return (ciSymbolKlass*)this; } ciKlassKlass* as_klass_klass() { assert(is_klass_klass(), "bad cast"); return (ciKlassKlass*)this; } ciInstanceKlassKlass* as_instance_klass_klass() { assert(is_instance_klass_klass(), "bad cast"); return (ciInstanceKlassKlass*)this; } ciArrayKlassKlass* as_array_klass_klass() { assert(is_array_klass_klass(), "bad cast"); return (ciArrayKlassKlass*)this; } ciObjArrayKlassKlass* as_obj_array_klass_klass() { assert(is_obj_array_klass_klass(), "bad cast"); return (ciObjArrayKlassKlass*)this; } ciTypeArrayKlassKlass* as_type_array_klass_klass() { assert(is_type_array_klass_klass(), "bad cast"); return (ciTypeArrayKlassKlass*)this; } // Print debugging output about this ciObject. void print(outputStream* st = tty); // Print debugging output about the oop this ciObject represents. void print_oop(outputStream* st = tty); };