Mercurial > hg > truffle
view src/share/vm/ci/ciObject.cpp @ 1949:058f494c8b6d
Merge
author | trims |
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date | Fri, 10 Dec 2010 15:46:59 -0800 |
parents | c18cbe5936b8 |
children | 2d26b0046e0d f95d63e2154a |
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/* * Copyright (c) 1999, 2007, 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 "incls/_precompiled.incl" #include "incls/_ciObject.cpp.incl" // 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. // ------------------------------------------------------------------ // ciObject::ciObject ciObject::ciObject(oop o) { ASSERT_IN_VM; if (ciObjectFactory::is_initialized()) { _handle = JNIHandles::make_local(o); } else { _handle = JNIHandles::make_global(o); } _klass = NULL; _ident = 0; 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; _ident = 0; 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; _ident = 0; } // ------------------------------------------------------------------ // ciObject::ciObject // // NULL variant. Used only by ciNullObject. ciObject::ciObject() { ASSERT_IN_VM; _handle = NULL; _klass = NULL; _ident = 0; } // ------------------------------------------------------------------ // 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_object(o->klass())->as_klass(); ); } return _klass; } // ------------------------------------------------------------------ // ciObject::set_ident // // Set the unique identity number of a ciObject. void ciObject::set_ident(uint id) { assert((_ident >> FLAG_BITS) == 0, "must only initialize once"); assert( id < ((uint)1 << (BitsPerInt-FLAG_BITS)), "id too big"); _ident = _ident + (id << FLAG_BITS); } // ------------------------------------------------------------------ // ciObject::ident // // Report the unique identity number of a ciObject. uint ciObject::ident() { uint id = _ident >> FLAG_BITS; assert(id != 0, "must be initialized"); return id; } // ------------------------------------------------------------------ // 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 || !is_scavengable(); } // ------------------------------------------------------------------ // ciObject::should_be_constant() bool ciObject::should_be_constant() { if (ScavengeRootsInCode >= 2) return true; // force everybody to be a constant return handle() == NULL || !is_scavengable(); } // ------------------------------------------------------------------ // 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%s address=0x%x>", ident(), is_perm() ? "PERM" : "", is_scavengable() ? "SCAVENGABLE" : "", (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);) } }