freebsd-skq/sys/sys/assym.h
mmacy 9a526826f9 make critical_{enter, exit} inline
Avoid pulling in all of the <sys/proc.h> dependencies by
automatically generating a stripped down thread_lite exporting
only the fields of interest. The field declarations are type checked
against the original and the offsets of the generated result is
automatically checked.

kib has expressed disagreement and would have preferred to simply
use genassym style offsets (which loses type check enforcement).
jhb has expressed dislike of it due to header pollution and a
duplicate structure. He would have preferred to just have defined
thread in _thread.h. Nonetheless, he admits that this is the only
viable solution at the moment.

The impetus for this came from mjg's D15331:
"Inline critical_enter/exit for amd64"

Reviewed by: jeff
Differential Revision: https://reviews.freebsd.org/D16078
2018-07-03 01:55:09 +00:00

62 lines
2.7 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1999 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _SYS_ASSYM_H_
#define _SYS_ASSYM_H_
#define ASSYM_BIAS 0x10000 /* avoid zero-length arrays */
#define ASSYM_ABS(value) ((value) < 0 ? -((value) + 1) + 1ULL : (value))
#define ASSYM(name, value) \
char name ## sign[((value) < 0 ? 1 : 0) + ASSYM_BIAS]; \
char name ## w0[(ASSYM_ABS(value) & 0xFFFFU) + ASSYM_BIAS]; \
char name ## w1[((ASSYM_ABS(value) & 0xFFFF0000UL) >> 16) + ASSYM_BIAS]; \
char name ## w2[((ASSYM_ABS(value) & 0xFFFF00000000ULL) >> 32) + ASSYM_BIAS]; \
char name ## w3[((ASSYM_ABS(value) & 0xFFFF000000000000ULL) >> 48) + ASSYM_BIAS]
/* char name ## _datatype_ ## STRINGIFY(typeof(((struct parenttype *)(0x0))-> name)) [1]; */
#ifdef OFFSET_TEST
#define OFFSET_CTASSERT CTASSERT
#else
#define OFFSET_CTASSERT(...)
#endif
#define OFFSYM(name, parenttype, datatype) \
ASSYM(name, offsetof(struct parenttype, name)); \
char name ## _datatype_ ## datatype [1]; \
char name ## _parenttype_ ## parenttype [1]; \
CTASSERT(__builtin_types_compatible_p(__typeof(((struct parenttype *)(0x0))-> name), datatype)); \
OFFSET_CTASSERT(offsetof(struct parenttype, name) == offsetof(struct parenttype ## _lite, name))
#endif /* !_SYS_ASSYM_H_ */