Mercurial > hg > graal-jvmci-8
view src/share/vm/runtime/fieldType.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 | c18cbe5936b8 |
children | f95d63e2154a |
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/* * Copyright (c) 1997, 2000, 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/_fieldType.cpp.incl" void FieldType::skip_optional_size(symbolOop signature, int* index) { jchar c = signature->byte_at(*index); while (c >= '0' && c <= '9') { *index = *index + 1; c = signature->byte_at(*index); } } BasicType FieldType::basic_type(symbolOop signature) { return char2type(signature->byte_at(0)); } // Check if it is a valid array signature bool FieldType::is_valid_array_signature(symbolOop sig) { assert(sig->utf8_length() > 1, "this should already have been checked"); assert(sig->byte_at(0) == '[', "this should already have been checked"); // The first character is already checked int i = 1; int len = sig->utf8_length(); // First skip all '['s while(i < len - 1 && sig->byte_at(i) == '[') i++; // Check type switch(sig->byte_at(i)) { case 'B': // T_BYTE case 'C': // T_CHAR case 'D': // T_DOUBLE case 'F': // T_FLOAT case 'I': // T_INT case 'J': // T_LONG case 'S': // T_SHORT case 'Z': // T_BOOLEAN // If it is an array, the type is the last character return (i + 1 == len); case 'L': // If it is an object, the last character must be a ';' return sig->byte_at(len - 1) == ';'; } return false; } BasicType FieldType::get_array_info(symbolOop signature, jint* dimension, symbolOop* object_key, TRAPS) { assert(basic_type(signature) == T_ARRAY, "must be array"); int index = 1; int dim = 1; skip_optional_size(signature, &index); while (signature->byte_at(index) == '[') { index++; dim++; skip_optional_size(signature, &index); } ResourceMark rm; symbolOop element = oopFactory::new_symbol(signature->as_C_string() + index, CHECK_(T_BYTE)); BasicType element_type = FieldType::basic_type(element); if (element_type == T_OBJECT) { char* object_type = element->as_C_string(); object_type[element->utf8_length() - 1] = '\0'; *object_key = oopFactory::new_symbol(object_type + 1, CHECK_(T_BYTE)); } // Pass dimension back to caller *dimension = dim; return element_type; }