aoqi@0: /*
aoqi@0:  * Copyright (c) 1999, 2014, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #include "precompiled.hpp"
aoqi@0: #include "ci/ciObject.hpp"
aoqi@0: #include "ci/ciUtilities.hpp"
aoqi@0: #include "gc_interface/collectedHeap.inline.hpp"
aoqi@0: #include "oops/oop.inline2.hpp"
aoqi@0: 
aoqi@0: // ciObject
aoqi@0: //
aoqi@0: // This class represents an oop in the HotSpot virtual machine.
aoqi@0: // Its subclasses are structured in a hierarchy which mirrors
aoqi@0: // an aggregate of the VM's oop and klass hierarchies (see
aoqi@0: // oopHierarchy.hpp).  Each instance of ciObject holds a handle
aoqi@0: // to a corresponding oop on the VM side and provides routines
aoqi@0: // for accessing the information in its oop.  By using the ciObject
aoqi@0: // hierarchy for accessing oops in the VM, the compiler ensures
aoqi@0: // that it is safe with respect to garbage collection; that is,
aoqi@0: // GC and compilation can proceed independently without
aoqi@0: // interference.
aoqi@0: //
aoqi@0: // Within the VM, the oop and klass hierarchies are separate.
aoqi@0: // The compiler interface does not preserve this separation --
aoqi@0: // the distinction between `Klass*' and `Klass' are not
aoqi@0: // reflected in the interface and instead the Klass hierarchy
aoqi@0: // is directly modeled as the subclasses of ciKlass.
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::ciObject
aoqi@0: ciObject::ciObject(oop o) {
aoqi@0:   ASSERT_IN_VM;
aoqi@0:   if (ciObjectFactory::is_initialized()) {
aoqi@0:     _handle = JNIHandles::make_local(o);
aoqi@0:   } else {
aoqi@0:     _handle = JNIHandles::make_global(o);
aoqi@0:   }
aoqi@0:   _klass = NULL;
aoqi@0:   init_flags_from(o);
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::ciObject
aoqi@0: //
aoqi@0: ciObject::ciObject(Handle h) {
aoqi@0:   ASSERT_IN_VM;
aoqi@0:   if (ciObjectFactory::is_initialized()) {
aoqi@0:     _handle = JNIHandles::make_local(h());
aoqi@0:   } else {
aoqi@0:     _handle = JNIHandles::make_global(h);
aoqi@0:   }
aoqi@0:   _klass = NULL;
aoqi@0:   init_flags_from(h());
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::ciObject
aoqi@0: //
aoqi@0: // Unloaded klass/method variant.  `klass' is the klass of the unloaded
aoqi@0: // klass/method, if that makes sense.
aoqi@0: ciObject::ciObject(ciKlass* klass) {
aoqi@0:   ASSERT_IN_VM;
aoqi@0:   assert(klass != NULL, "must supply klass");
aoqi@0:   _handle = NULL;
aoqi@0:   _klass = klass;
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::ciObject
aoqi@0: //
aoqi@0: // NULL variant.  Used only by ciNullObject.
aoqi@0: ciObject::ciObject() {
aoqi@0:   ASSERT_IN_VM;
aoqi@0:   _handle = NULL;
aoqi@0:   _klass = NULL;
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::klass
aoqi@0: //
aoqi@0: // Get the ciKlass of this ciObject.
aoqi@0: ciKlass* ciObject::klass() {
aoqi@0:   if (_klass == NULL) {
aoqi@0:     if (_handle == NULL) {
aoqi@0:       // When both _klass and _handle are NULL, we are dealing
aoqi@0:       // with the distinguished instance of ciNullObject.
aoqi@0:       // No one should ask it for its klass.
aoqi@0:       assert(is_null_object(), "must be null object");
aoqi@0:       ShouldNotReachHere();
aoqi@0:       return NULL;
aoqi@0:     }
aoqi@0: 
aoqi@0:     GUARDED_VM_ENTRY(
aoqi@0:       oop o = get_oop();
aoqi@0:       _klass = CURRENT_ENV->get_klass(o->klass());
aoqi@0:     );
aoqi@0:   }
aoqi@0:   return _klass;
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::equals
aoqi@0: //
aoqi@0: // Are two ciObjects equal?
aoqi@0: bool ciObject::equals(ciObject* obj) {
aoqi@0:   return (this == obj);
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::hash
aoqi@0: //
aoqi@0: // A hash value for the convenience of compilers.
aoqi@0: //
aoqi@0: // Implementation note: we use the address of the ciObject as the
aoqi@0: // basis for the hash.  Use the _ident field, which is well-behaved.
aoqi@0: int ciObject::hash() {
aoqi@0:   return ident() * 31;
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::constant_encoding
aoqi@0: //
aoqi@0: // The address which the compiler should embed into the
aoqi@0: // generated code to represent this oop.  This address
aoqi@0: // is not the true address of the oop -- it will get patched
aoqi@0: // during nmethod creation.
aoqi@0: //
aoqi@0: //
aoqi@0: //
aoqi@0: // Implementation note: we use the handle as the encoding.  The
aoqi@0: // nmethod constructor resolves the handle and patches in the oop.
aoqi@0: //
aoqi@0: // This method should be changed to return an generified address
aoqi@0: // to discourage use of the JNI handle.
aoqi@0: jobject ciObject::constant_encoding() {
aoqi@0:   assert(is_null_object() || handle() != NULL, "cannot embed null pointer");
aoqi@0:   assert(can_be_constant(), "oop must be NULL or perm");
aoqi@0:   return handle();
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::can_be_constant
aoqi@0: bool ciObject::can_be_constant() {
aoqi@0:   if (ScavengeRootsInCode >= 1)  return true;  // now everybody can encode as a constant
aoqi@0:   return handle() == NULL;
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::should_be_constant()
aoqi@0: bool ciObject::should_be_constant() {
aoqi@0:   if (ScavengeRootsInCode >= 2)  return true;  // force everybody to be a constant
aoqi@0:   if (is_null_object()) return true;
aoqi@0: 
aoqi@0:   ciEnv* env = CURRENT_ENV;
aoqi@0: 
aoqi@0:     // We want Strings and Classes to be embeddable by default since
aoqi@0:     // they used to be in the perm world.  Not all Strings used to be
aoqi@0:     // embeddable but there's no easy way to distinguish the interned
aoqi@0:     // from the regulars ones so just treat them all that way.
aoqi@0:     if (klass() == env->String_klass() || klass() == env->Class_klass()) {
aoqi@0:       return true;
aoqi@0:     }
aoqi@0:   if (EnableInvokeDynamic &&
aoqi@0:       (klass()->is_subclass_of(env->MethodHandle_klass()) ||
aoqi@0:        klass()->is_subclass_of(env->CallSite_klass()))) {
aoqi@0:     assert(ScavengeRootsInCode >= 1, "must be");
aoqi@0:     // We want to treat these aggressively.
aoqi@0:     return true;
aoqi@0:   }
aoqi@0: 
aoqi@0:   return handle() == NULL;
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::should_be_constant()
aoqi@0: void ciObject::init_flags_from(oop x) {
aoqi@0:   int flags = 0;
aoqi@0:   if (x != NULL) {
aoqi@0:     assert(Universe::heap()->is_in_reserved(x), "must be");
aoqi@0:     if (x->is_scavengable())
aoqi@0:       flags |= SCAVENGABLE_FLAG;
aoqi@0:   }
aoqi@0:   _ident |= flags;
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::print
aoqi@0: //
aoqi@0: // Print debugging output about this ciObject.
aoqi@0: //
aoqi@0: // Implementation note: dispatch to the virtual print_impl behavior
aoqi@0: // for this ciObject.
aoqi@0: void ciObject::print(outputStream* st) {
aoqi@0:   st->print("<%s", type_string());
aoqi@0:   GUARDED_VM_ENTRY(print_impl(st);)
aoqi@0:   st->print(" ident=%d %s address=" INTPTR_FORMAT ">", ident(),
aoqi@0:         is_scavengable() ? "SCAVENGABLE" : "",
aoqi@0:         p2i((address)this));
aoqi@0: }
aoqi@0: 
aoqi@0: // ------------------------------------------------------------------
aoqi@0: // ciObject::print_oop
aoqi@0: //
aoqi@0: // Print debugging output about the oop this ciObject represents.
aoqi@0: void ciObject::print_oop(outputStream* st) {
aoqi@0:   if (is_null_object()) {
aoqi@0:     st->print_cr("NULL");
aoqi@0:   } else if (!is_loaded()) {
aoqi@0:     st->print_cr("UNLOADED");
aoqi@0:   } else {
aoqi@0:     GUARDED_VM_ENTRY(get_oop()->print_on(st);)
aoqi@0:   }
aoqi@0: }