Mercurial > hg > truffle
view src/share/vm/ci/ciConstant.hpp @ 20543:e7d0505c8a30
8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso
author | tschatzl |
---|---|
date | Fri, 10 Oct 2014 15:51:58 +0200 |
parents | 55fb97c4c58d |
children | 4ca6dc0799b6 |
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/* * Copyright (c) 1999, 2013, 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. * */ #ifndef SHARE_VM_CI_CICONSTANT_HPP #define SHARE_VM_CI_CICONSTANT_HPP #include "ci/ciClassList.hpp" #include "ci/ciNullObject.hpp" // ciConstant // // This class represents a constant value. class ciConstant VALUE_OBJ_CLASS_SPEC { friend class VMStructs; private: friend class ciEnv; friend class ciField; BasicType _type; union { jint _int; jlong _long; jfloat _float; jdouble _double; ciObject* _object; } _value; public: ciConstant() { _type = T_ILLEGAL; _value._long = -1; } ciConstant(BasicType type, jint value) { assert(type != T_LONG && type != T_DOUBLE && type != T_FLOAT, "using the wrong ciConstant constructor"); _type = type; _value._int = value; } ciConstant(jlong value) { _type = T_LONG; _value._long = value; } ciConstant(jfloat value) { _type = T_FLOAT; _value._float = value; } ciConstant(jdouble value) { _type = T_DOUBLE; _value._double = value; } ciConstant(BasicType type, ciObject* p) { _type = type; _value._object = p; } BasicType basic_type() const { return _type; } jboolean as_boolean() { assert(basic_type() == T_BOOLEAN, "wrong type"); return (jboolean)_value._int; } jchar as_char() { assert(basic_type() == T_CHAR, "wrong type"); return (jchar)_value._int; } jbyte as_byte() { assert(basic_type() == T_BYTE, "wrong type"); return (jbyte)_value._int; } jshort as_short() { assert(basic_type() == T_SHORT, "wrong type"); return (jshort)_value._int; } jint as_int() { assert(basic_type() == T_BOOLEAN || basic_type() == T_CHAR || basic_type() == T_BYTE || basic_type() == T_SHORT || basic_type() == T_INT, "wrong type"); return _value._int; } jlong as_long() { assert(basic_type() == T_LONG, "wrong type"); return _value._long; } jfloat as_float() { assert(basic_type() == T_FLOAT, "wrong type"); return _value._float; } jdouble as_double() { assert(basic_type() == T_DOUBLE, "wrong type"); return _value._double; } ciObject* as_object() const { assert(basic_type() == T_OBJECT || basic_type() == T_ARRAY, "wrong type"); return _value._object; } bool is_null_or_zero() const { if (!is_java_primitive(basic_type())) { return as_object()->is_null_object(); } else if (type2size[basic_type()] == 1) { // treat float bits as int, to avoid comparison with -0 and NaN return (_value._int == 0); } else if (type2size[basic_type()] == 2) { // treat double bits as long, to avoid comparison with -0 and NaN return (_value._long == 0); } else { return false; } } // Debugging output void print(); }; #endif // SHARE_VM_CI_CICONSTANT_HPP