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src/share/vm/utilities/sizes.hpp@1d1603768966 (annotated)

src/share/vm/utilities/sizes.hpp

Tue, 05 Apr 2011 14:12:31 -0700

author

trims

date

Tue, 05 Apr 2011 14:12:31 -0700

changeset 2708

1d1603768966

parent 2314

f95d63e2154a

child 6876

710a3c8b516e

permissions

-rw-r--r--

7010070: Update all 2010 Oracle-changed OpenJDK files to have the proper copyright dates - second pass
Summary: Update the copyright to be 2010 on all changed files in OpenJDK
Reviewed-by: ohair

duke@435	1	/*
stefank@2314	2	* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
stefank@2314	25	#ifndef SHARE_VM_UTILITIES_SIZES_HPP
stefank@2314	26	#define SHARE_VM_UTILITIES_SIZES_HPP
stefank@2314	27
stefank@2314	28	#include "memory/allocation.hpp"
stefank@2314	29	#include "utilities/globalDefinitions.hpp"
stefank@2314	30
duke@435	31	// The following two classes are used to represent 'sizes' and 'offsets' in the VM;
duke@435	32	// they serve as 'unit' types. ByteSize is used for sizes measured in bytes, while
duke@435	33	// WordSize is used for sizes measured in machine words (i.e., 32bit or 64bit words
duke@435	34	// depending on platform).
duke@435	35	//
duke@435	36	// The classes are defined with friend functions operating on them instead of member
duke@435	37	// functions so that they (the classes) can be re-#define'd to int types in optimized
duke@435	38	// mode. This allows full type checking and maximum safety in debug mode, and full
duke@435	39	// optimizations (constant folding) and zero overhead (time and space wise) in the
duke@435	40	// optimized build (some compilers do not optimize one-element value classes but
duke@435	41	// instead create an object in memory - thus the overhead may be significant).
duke@435	42	//
duke@435	43	// Note: 1) DO NOT add new overloaded friend functions that do not have a unique function
duke@435	44	// function name but require signature types for resolution. This will not work
duke@435	45	// in optimized mode as both, ByteSize and WordSize are mapped to the same type
duke@435	46	// and thus the distinction would not be possible anymore (=> compiler errors).
duke@435	47	//
duke@435	48	// 2) DO NOT add non-static member functions as they cannot be mapped so something
duke@435	49	// compilable in the optimized build. Static member functions could be added
duke@435	50	// but require a corresponding class definition in the optimized build.
duke@435	51	//
duke@435	52	// These classes should help doing a transition from (currently) word-size based offsets
duke@435	53	// to byte-size based offsets in the VM (this will be important if we desire to pack
duke@435	54	// objects more densely in the VM for 64bit machines). Such a transition should proceed
duke@435	55	// in two steps to minimize the risk of introducing hard-to-find bugs:
duke@435	56	//
duke@435	57	// a) first transition the whole VM into a form where all sizes are strongly typed
duke@435	58	// b) change all WordSize's to ByteSize's where desired and fix the compilation errors
duke@435	59
duke@435	60
duke@435	61	#ifdef ASSERT
duke@435	62
duke@435	63	class ByteSize VALUE_OBJ_CLASS_SPEC {
duke@435	64	private:
duke@435	65	int _size;
duke@435	66
duke@435	67	// Note: This constructor must be private to avoid implicit conversions!
duke@435	68	ByteSize(int size) { _size = size; }
duke@435	69
duke@435	70	public:
duke@435	71	// constructors
duke@435	72	inline friend ByteSize in_ByteSize(int size);
duke@435	73
duke@435	74	// accessors
duke@435	75	inline friend int in_bytes(ByteSize x);
duke@435	76
duke@435	77	// operators
duke@435	78	friend ByteSize operator + (ByteSize x, ByteSize y) { return ByteSize(in_bytes(x) + in_bytes(y)); }
duke@435	79	friend ByteSize operator - (ByteSize x, ByteSize y) { return ByteSize(in_bytes(x) - in_bytes(y)); }
duke@435	80	friend ByteSize operator * (ByteSize x, int y) { return ByteSize(in_bytes(x) * y ); }
duke@435	81
duke@435	82	// comparison
duke@435	83	friend bool operator == (ByteSize x, ByteSize y) { return in_bytes(x) == in_bytes(y); }
duke@435	84	friend bool operator != (ByteSize x, ByteSize y) { return in_bytes(x) != in_bytes(y); }
duke@435	85	friend bool operator < (ByteSize x, ByteSize y) { return in_bytes(x) < in_bytes(y); }
duke@435	86	friend bool operator <= (ByteSize x, ByteSize y) { return in_bytes(x) <= in_bytes(y); }
duke@435	87	friend bool operator > (ByteSize x, ByteSize y) { return in_bytes(x) > in_bytes(y); }
duke@435	88	friend bool operator >= (ByteSize x, ByteSize y) { return in_bytes(x) >= in_bytes(y); }
duke@435	89	};
duke@435	90
duke@435	91	inline ByteSize in_ByteSize(int size) { return ByteSize(size); }
duke@435	92	inline int in_bytes(ByteSize x) { return x._size; }
duke@435	93
duke@435	94
duke@435	95	class WordSize VALUE_OBJ_CLASS_SPEC {
duke@435	96	private:
duke@435	97	int _size;
duke@435	98
duke@435	99	// Note: This constructor must be private to avoid implicit conversions!
duke@435	100	WordSize(int size) { _size = size; }
duke@435	101
duke@435	102	public:
duke@435	103	// constructors
duke@435	104	inline friend WordSize in_WordSize(int size);
duke@435	105
duke@435	106	// accessors
duke@435	107	inline friend int in_words(WordSize x);
duke@435	108
duke@435	109	// operators
duke@435	110	friend WordSize operator + (WordSize x, WordSize y) { return WordSize(in_words(x) + in_words(y)); }
duke@435	111	friend WordSize operator - (WordSize x, WordSize y) { return WordSize(in_words(x) - in_words(y)); }
duke@435	112	friend WordSize operator * (WordSize x, int y) { return WordSize(in_words(x) * y ); }
duke@435	113
duke@435	114	// comparison
duke@435	115	friend bool operator == (WordSize x, WordSize y) { return in_words(x) == in_words(y); }
duke@435	116	friend bool operator != (WordSize x, WordSize y) { return in_words(x) != in_words(y); }
duke@435	117	friend bool operator < (WordSize x, WordSize y) { return in_words(x) < in_words(y); }
duke@435	118	friend bool operator <= (WordSize x, WordSize y) { return in_words(x) <= in_words(y); }
duke@435	119	friend bool operator > (WordSize x, WordSize y) { return in_words(x) > in_words(y); }
duke@435	120	friend bool operator >= (WordSize x, WordSize y) { return in_words(x) >= in_words(y); }
duke@435	121	};
duke@435	122
duke@435	123	inline WordSize in_WordSize(int size) { return WordSize(size); }
duke@435	124	inline int in_words(WordSize x) { return x._size; }
duke@435	125
duke@435	126
duke@435	127	#else // ASSERT
duke@435	128
duke@435	129	// The following definitions must match the corresponding friend declarations
duke@435	130	// in the Byte/WordSize classes if they are typedef'ed to be int. This will
duke@435	131	// be the case in optimized mode to ensure zero overhead for these types.
duke@435	132	//
duke@435	133	// Note: If a compiler does not inline these function calls away, one may
duke@435	134	// want to use #define's to make sure full optimization (constant
duke@435	135	// folding in particular) is possible.
duke@435	136
duke@435	137	typedef int ByteSize;
duke@435	138	inline ByteSize in_ByteSize(int size) { return size; }
duke@435	139	inline int in_bytes (ByteSize x) { return x; }
duke@435	140
duke@435	141	typedef int WordSize;
duke@435	142	inline WordSize in_WordSize(int size) { return size; }
duke@435	143	inline int in_words (WordSize x) { return x; }
duke@435	144
duke@435	145	#endif // ASSERT
duke@435	146
duke@435	147
duke@435	148	// Use the following #define to get C++ field member offsets
duke@435	149
duke@435	150	#define byte_offset_of(klass,field) in_ByteSize((int)offset_of(klass, field))
stefank@2314	151
stefank@2314	152	#endif // SHARE_VM_UTILITIES_SIZES_HPP