| /* |
| * Copyright (c) 1999, 2017, 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. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "ci/ciObject.hpp" |
| #include "ci/ciUtilities.hpp" |
| #include "gc/shared/collectedHeap.inline.hpp" |
| #include "oops/oop.inline.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. |
| |
| // ------------------------------------------------------------------ |
| // ciObject::ciObject |
| ciObject::ciObject(oop o) { |
| ASSERT_IN_VM; |
| if (ciObjectFactory::is_initialized()) { |
| _handle = JNIHandles::make_local(o); |
| } else { |
| Handle obj(Thread::current(), o); |
| _handle = JNIHandles::make_global(obj); |
| } |
| _klass = NULL; |
| init_flags_from(o); |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::ciObject |
| // |
| ciObject::ciObject(Handle h) { |
| ASSERT_IN_VM; |
| if (ciObjectFactory::is_initialized()) { |
| _handle = JNIHandles::make_local(h()); |
| } else { |
| _handle = JNIHandles::make_global(h); |
| } |
| _klass = NULL; |
| init_flags_from(h()); |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::ciObject |
| // |
| // Unloaded klass/method variant. `klass' is the klass of the unloaded |
| // klass/method, if that makes sense. |
| ciObject::ciObject(ciKlass* klass) { |
| ASSERT_IN_VM; |
| assert(klass != NULL, "must supply klass"); |
| _handle = NULL; |
| _klass = klass; |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::ciObject |
| // |
| // NULL variant. Used only by ciNullObject. |
| ciObject::ciObject() { |
| ASSERT_IN_VM; |
| _handle = NULL; |
| _klass = NULL; |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::klass |
| // |
| // Get the ciKlass of this ciObject. |
| ciKlass* ciObject::klass() { |
| if (_klass == NULL) { |
| if (_handle == NULL) { |
| // When both _klass and _handle are NULL, we are dealing |
| // with the distinguished instance of ciNullObject. |
| // No one should ask it for its klass. |
| assert(is_null_object(), "must be null object"); |
| ShouldNotReachHere(); |
| return NULL; |
| } |
| |
| GUARDED_VM_ENTRY( |
| oop o = get_oop(); |
| _klass = CURRENT_ENV->get_klass(o->klass()); |
| ); |
| } |
| return _klass; |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::equals |
| // |
| // Are two ciObjects equal? |
| bool ciObject::equals(ciObject* obj) { |
| return (this == obj); |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::hash |
| // |
| // A hash value for the convenience of compilers. |
| // |
| // Implementation note: we use the address of the ciObject as the |
| // basis for the hash. Use the _ident field, which is well-behaved. |
| int ciObject::hash() { |
| return ident() * 31; |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::constant_encoding |
| // |
| // 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. |
| // |
| // |
| // |
| // Implementation note: we use the handle as the encoding. The |
| // nmethod constructor resolves the handle and patches in the oop. |
| // |
| // This method should be changed to return an generified address |
| // to discourage use of the JNI handle. |
| jobject ciObject::constant_encoding() { |
| assert(is_null_object() || handle() != NULL, "cannot embed null pointer"); |
| assert(can_be_constant(), "oop must be NULL or perm"); |
| return handle(); |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::can_be_constant |
| bool ciObject::can_be_constant() { |
| if (ScavengeRootsInCode >= 1) return true; // now everybody can encode as a constant |
| return handle() == NULL; |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::should_be_constant() |
| bool ciObject::should_be_constant() { |
| if (ScavengeRootsInCode >= 2) return true; // force everybody to be a constant |
| if (is_null_object()) return true; |
| |
| ciEnv* env = CURRENT_ENV; |
| |
| // We want Strings and Classes to be embeddable by default since |
| // they used to be in the perm world. Not all Strings used to be |
| // embeddable but there's no easy way to distinguish the interned |
| // from the regulars ones so just treat them all that way. |
| if (klass() == env->String_klass() || klass() == env->Class_klass()) { |
| return true; |
| } |
| if (klass()->is_subclass_of(env->MethodHandle_klass()) || |
| klass()->is_subclass_of(env->CallSite_klass())) { |
| assert(ScavengeRootsInCode >= 1, "must be"); |
| // We want to treat these aggressively. |
| return true; |
| } |
| |
| return handle() == NULL; |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::should_be_constant() |
| void ciObject::init_flags_from(oop x) { |
| int flags = 0; |
| if (x != NULL) { |
| assert(Universe::heap()->is_in_reserved(x), "must be"); |
| if (x->is_scavengable()) |
| flags |= SCAVENGABLE_FLAG; |
| } |
| _ident |= flags; |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::print |
| // |
| // Print debugging output about this ciObject. |
| // |
| // Implementation note: dispatch to the virtual print_impl behavior |
| // for this ciObject. |
| void ciObject::print(outputStream* st) { |
| st->print("<%s", type_string()); |
| GUARDED_VM_ENTRY(print_impl(st);) |
| st->print(" ident=%d %s address=" INTPTR_FORMAT ">", ident(), |
| is_scavengable() ? "SCAVENGABLE" : "", |
| p2i((address)this)); |
| } |
| |
| // ------------------------------------------------------------------ |
| // ciObject::print_oop |
| // |
| // Print debugging output about the oop this ciObject represents. |
| void ciObject::print_oop(outputStream* st) { |
| if (is_null_object()) { |
| st->print_cr("NULL"); |
| } else if (!is_loaded()) { |
| st->print_cr("UNLOADED"); |
| } else { |
| GUARDED_VM_ENTRY(get_oop()->print_on(st);) |
| } |
| } |