Mercurial > hg > graal-jvmci-8
view src/share/vm/oops/cpCacheKlass.cpp @ 1716:be3f9c242c9d
6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
Summary: GC workers now recognize an intermediate transient state of blocks which are allocated but have not yet completed initialization. blk_start() calls do not attempt to determine the size of a block in the transient state, rather waiting for the block to become initialized so that it is safe to query its size. Audited and ensured the order of initialization of object fields (klass, free bit and size) to respect block state transition protocol. Also included some new assertion checking code enabled in debug mode.
Reviewed-by: chrisphi, johnc, poonam
author | ysr |
---|---|
date | Mon, 16 Aug 2010 15:58:42 -0700 |
parents | 7fcd5f39bd7a |
children | f95d63e2154a |
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/* * Copyright (c) 1998, 2009, 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/_cpCacheKlass.cpp.incl" int constantPoolCacheKlass::oop_size(oop obj) const { assert(obj->is_constantPoolCache(), "must be constantPool"); return constantPoolCacheOop(obj)->object_size(); } constantPoolCacheOop constantPoolCacheKlass::allocate(int length, bool is_conc_safe, TRAPS) { // allocate memory int size = constantPoolCacheOopDesc::object_size(length); KlassHandle klass (THREAD, as_klassOop()); // This is the original code. The code from permanent_obj_allocate() // was in-lined to allow the setting of is_conc_safe before the klass // is installed. // constantPoolCacheOop cache = (constantPoolCacheOop) // CollectedHeap::permanent_obj_allocate(klass, size, CHECK_NULL); oop obj = CollectedHeap::permanent_obj_allocate_no_klass_install(klass, size, CHECK_NULL); constantPoolCacheOop cache = (constantPoolCacheOop) obj; cache->set_is_conc_safe(is_conc_safe); // The store to is_conc_safe must be visible before the klass // is set. This should be done safely because _is_conc_safe has // been declared volatile. If there are any problems, consider adding // OrderAccess::storestore(); CollectedHeap::post_allocation_install_obj_klass(klass, obj, size); NOT_PRODUCT(Universe::heap()->check_for_bad_heap_word_value((HeapWord*) obj, size)); // The length field affects the size of the object. The allocation // above allocates the correct size (see calculation of "size") but // the size() method of the constant pool cache oop will not reflect // that size until the correct length is set. cache->set_length(length); // The store of the length must be visible before is_conc_safe is // set to a safe state. // This should be done safely because _is_conc_safe has // been declared volatile. If there are any problems, consider adding // OrderAccess::storestore(); cache->set_is_conc_safe(methodOopDesc::IsSafeConc); cache->set_constant_pool(NULL); return cache; } klassOop constantPoolCacheKlass::create_klass(TRAPS) { constantPoolCacheKlass o; KlassHandle h_this_klass(THREAD, Universe::klassKlassObj()); KlassHandle k = base_create_klass(h_this_klass, header_size(), o.vtbl_value(), CHECK_NULL); // Make sure size calculation is right assert(k()->size() == align_object_size(header_size()), "wrong size for object"); java_lang_Class::create_mirror(k, CHECK_NULL); // Allocate mirror return k(); } void constantPoolCacheKlass::oop_follow_contents(oop obj) { assert(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; // Performance tweak: We skip iterating over the klass pointer since we // know that Universe::constantPoolCacheKlassObj never moves. // gc of constant pool cache instance variables MarkSweep::mark_and_push((oop*)cache->constant_pool_addr()); // gc of constant pool cache entries int i = cache->length(); while (i-- > 0) cache->entry_at(i)->follow_contents(); } #ifndef SERIALGC void constantPoolCacheKlass::oop_follow_contents(ParCompactionManager* cm, oop obj) { assert(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; // Performance tweak: We skip iterating over the klass pointer since we // know that Universe::constantPoolCacheKlassObj never moves. // gc of constant pool cache instance variables PSParallelCompact::mark_and_push(cm, (oop*)cache->constant_pool_addr()); // gc of constant pool cache entries int i = cache->length(); while (i-- > 0) cache->entry_at(i)->follow_contents(cm); } #endif // SERIALGC int constantPoolCacheKlass::oop_oop_iterate(oop obj, OopClosure* blk) { assert(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; // Get size before changing pointers. // Don't call size() or oop_size() since that is a virtual call. int size = cache->object_size(); // Performance tweak: We skip iterating over the klass pointer since we // know that Universe::constantPoolCacheKlassObj never moves. // iteration over constant pool cache instance variables blk->do_oop((oop*)cache->constant_pool_addr()); // iteration over constant pool cache entries for (int i = 0; i < cache->length(); i++) cache->entry_at(i)->oop_iterate(blk); return size; } int constantPoolCacheKlass::oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) { assert(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; // Get size before changing pointers. // Don't call size() or oop_size() since that is a virtual call. int size = cache->object_size(); // Performance tweak: We skip iterating over the klass pointer since we // know that Universe::constantPoolCacheKlassObj never moves. // iteration over constant pool cache instance variables oop* addr = (oop*)cache->constant_pool_addr(); if (mr.contains(addr)) blk->do_oop(addr); // iteration over constant pool cache entries for (int i = 0; i < cache->length(); i++) cache->entry_at(i)->oop_iterate_m(blk, mr); return size; } int constantPoolCacheKlass::oop_adjust_pointers(oop obj) { assert(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; // Get size before changing pointers. // Don't call size() or oop_size() since that is a virtual call. int size = cache->object_size(); // Performance tweak: We skip iterating over the klass pointer since we // know that Universe::constantPoolCacheKlassObj never moves. // Iteration over constant pool cache instance variables MarkSweep::adjust_pointer((oop*)cache->constant_pool_addr()); // iteration over constant pool cache entries for (int i = 0; i < cache->length(); i++) cache->entry_at(i)->adjust_pointers(); return size; } bool constantPoolCacheKlass::oop_is_conc_safe(oop obj) const { assert(obj->is_constantPoolCache(), "should be constant pool"); return constantPoolCacheOop(obj)->is_conc_safe(); } #ifndef SERIALGC void constantPoolCacheKlass::oop_push_contents(PSPromotionManager* pm, oop obj) { assert(obj->is_constantPoolCache(), "should be constant pool"); if (EnableInvokeDynamic) { constantPoolCacheOop cache = (constantPoolCacheOop)obj; // during a scavenge, it is safe to inspect my pool, since it is perm constantPoolOop pool = cache->constant_pool(); assert(pool->is_constantPool(), "should be constant pool"); if (pool->has_invokedynamic()) { for (int i = 0; i < cache->length(); i++) { ConstantPoolCacheEntry* e = cache->entry_at(i); oop* p = (oop*)&e->_f1; if (e->is_secondary_entry()) { if (PSScavenge::should_scavenge(p)) pm->claim_or_forward_depth(p); assert(!(e->is_vfinal() && PSScavenge::should_scavenge((oop*)&e->_f2)), "no live oops here"); } } } } } int constantPoolCacheKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) { assert(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; // Iteration over constant pool cache instance variables PSParallelCompact::adjust_pointer((oop*)cache->constant_pool_addr()); // iteration over constant pool cache entries for (int i = 0; i < cache->length(); ++i) { cache->entry_at(i)->update_pointers(); } return cache->object_size(); } int constantPoolCacheKlass::oop_update_pointers(ParCompactionManager* cm, oop obj, HeapWord* beg_addr, HeapWord* end_addr) { assert(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; // Iteration over constant pool cache instance variables oop* p; p = (oop*)cache->constant_pool_addr(); PSParallelCompact::adjust_pointer(p, beg_addr, end_addr); // Iteration over constant pool cache entries for (int i = 0; i < cache->length(); ++i) { cache->entry_at(i)->update_pointers(beg_addr, end_addr); } return cache->object_size(); } #endif // SERIALGC void constantPoolCacheKlass::oop_print_on(oop obj, outputStream* st) { assert(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; // super print Klass::oop_print_on(obj, st); // print constant pool cache entries for (int i = 0; i < cache->length(); i++) cache->entry_at(i)->print(st, i); } void constantPoolCacheKlass::oop_print_value_on(oop obj, outputStream* st) { assert(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; st->print("cache [%d]", cache->length()); cache->print_address_on(st); st->print(" for "); cache->constant_pool()->print_value_on(st); } void constantPoolCacheKlass::oop_verify_on(oop obj, outputStream* st) { guarantee(obj->is_constantPoolCache(), "obj must be constant pool cache"); constantPoolCacheOop cache = (constantPoolCacheOop)obj; // super verify Klass::oop_verify_on(obj, st); // print constant pool cache entries for (int i = 0; i < cache->length(); i++) cache->entry_at(i)->verify(st); } const char* constantPoolCacheKlass::internal_name() const { return "{constant pool cache}"; }