295 lines
9.5 KiB
C
295 lines
9.5 KiB
C
/* Copyright (C) 2012-2022 Free Software Foundation, Inc.
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Contributed by Richard Henderson <rth@redhat.com>.
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This file is part of the GNU Atomic Library (libatomic).
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Libatomic is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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Libatomic is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* This file contains data types and function declarations that are
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private to the implementation of libatomic. */
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#ifndef LIBATOMIC_H
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#define LIBATOMIC_H 1
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#include "auto-config.h"
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#include <stdbool.h>
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#include <stdint.h>
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#include <stddef.h>
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#include <limits.h>
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#include <string.h>
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/* Symbol concatenation macros. */
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#define C2_(X,Y) X ## Y
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#define C2(X,Y) C2_(X,Y)
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#define C3_(X,Y,Z) X ## Y ## Z
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#define C3(X,Y,Z) C3_(X,Y,Z)
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#define C4_(W,X,Y,Z) W ## X ## Y ## Z
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#define C4(W,X,Y,Z) C4_(W,X,Y,Z)
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/* Stringification macros. */
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#define S2(X) #X
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#define S(X) S2(X)
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/* All of the primitive types on which we operate. */
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typedef unsigned U_1 __attribute__((mode(QI)));
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#if HAVE_INT2
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typedef unsigned U_2 __attribute__((mode(HI)));
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#endif
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#if HAVE_INT4
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typedef unsigned U_4 __attribute__((mode(SI)));
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#endif
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#if HAVE_INT8
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typedef unsigned U_8 __attribute__((mode(DI)));
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#endif
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#if HAVE_INT16
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typedef unsigned U_16 __attribute__((mode(TI)));
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#endif
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/* The widest type that we support. */
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#if HAVE_INT16
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# define MAX_SIZE 16
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#elif HAVE_INT8
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# define MAX_SIZE 8
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#elif HAVE_INT4
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# define MAX_SIZE 4
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#elif HAVE_INT2
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# define MAX_SIZE 2
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#else
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# define MAX_SIZE 1
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#endif
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typedef C2(U_,MAX_SIZE) U_MAX;
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/* Provide dummy fallback types so that stuff is syntactically correct
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without having to overdo the ifdefs. The code using these should
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always be protected with the HAVE_INT{n} macros. */
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#if !HAVE_INT2
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typedef U_MAX U_2;
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#endif
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#if !HAVE_INT4
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typedef U_MAX U_4;
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#endif
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#if !HAVE_INT8
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typedef U_MAX U_8;
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#endif
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#if !HAVE_INT16
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typedef U_MAX U_16;
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#endif
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union max_size_u
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{
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U_1 b[MAX_SIZE];
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U_2 i2;
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U_4 i4;
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U_8 i8;
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U_16 i16;
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};
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/* The "word" size of the machine. */
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typedef unsigned UWORD __attribute__((mode(word)));
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/* Macros for handing sub-word sized quantities. */
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#define MASK_1 ((UWORD)0xff)
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#define MASK_2 ((UWORD)0xffff)
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#define MASK_4 ((UWORD)0xffffffff)
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#define MASK_8 ((UWORD)0xffffffffffffffff)
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#define INVERT_MASK_1 ((UWORD)WORDS_BIGENDIAN << ((WORDSIZE - 1) * CHAR_BIT))
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#define INVERT_MASK_2 ((UWORD)WORDS_BIGENDIAN << ((WORDSIZE - 2) * CHAR_BIT))
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#define INVERT_MASK_4 ((UWORD)WORDS_BIGENDIAN << ((WORDSIZE - 4) * CHAR_BIT))
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#define INVERT_MASK_8 ((UWORD)WORDS_BIGENDIAN << ((WORDSIZE - 8) * CHAR_BIT))
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/* Most of the files in this library are compiled multiple times with
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N defined to be a power of 2 between 1 and 16. The SIZE macro is
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then used to append _N to the symbol being manipulated. */
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#define SIZE(X) C3(X,_,N)
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#define WSIZE(X) C3(X,_,WORDSIZE)
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#define PTR(N,X) ((C2(U_,N) *)X)
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/* And thus, the type on which this compilation will be operating. */
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#define ITYPE SIZE(I)
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#define UTYPE SIZE(U)
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/* Utility macros for GCC attributes. */
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#define UNUSED __attribute__((unused))
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#ifdef HAVE_ATTRIBUTE_VISIBILITY
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# define HIDDEN __attribute__((visibility("hidden")))
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#else
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# define HIDDEN
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#endif
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/* Occasionally we have to play games with internal and external symbol
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names, in order to work around builtin functions of the same name.
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This macro sets the external name of the function appropriately. */
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#define ASMNAME(X) __asm__(S(C2(__USER_LABEL_PREFIX__,X)))
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/* Locking for a "small" operation. In the bare-metal single processor
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cases this could be implemented by disabling interrupts. Thus the extra
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word passed between the two functions, saving the interrupt level.
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It is assumed that the object being locked does not cross the locking
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granularity.
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Not actually declared here so that they can be defined static inline
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in a target-specfic <host-config.h>.
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UWORD protect_start (void *ptr);
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void protect_end (void *ptr, UWORD);
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*/
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/* Locking for a "large' operation. This should always be some sort of
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test-and-set operation, as we assume that the interrupt latency would
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be unreasonably large. */
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void libat_lock_n (void *ptr, size_t n);
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void libat_unlock_n (void *ptr, size_t n);
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/* We'll need to declare all of the sized functions a few times... */
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#define DECLARE_ALL_SIZED(N) DECLARE_ALL_SIZED_(N,C2(U_,N))
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#define DECLARE_ALL_SIZED_(N,T) \
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DECLARE_1(T, C2(load_,N), (T *mptr, int)); \
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DECLARE_1(void, C2(store_,N), (T *mptr, T val, int)); \
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DECLARE_1(T, C2(exchange_,N), (T *mptr, T, int)); \
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DECLARE_1(bool, C2(compare_exchange_,N), (T *mptr, T *, T, int, int)); \
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DECLARE_1(bool, C2(test_and_set_,N), (T *mptr, int)); \
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DECLARE_1(T, C2(fetch_add_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(fetch_sub_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(fetch_and_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(fetch_xor_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(fetch_or_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(fetch_nand_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(add_fetch_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(sub_fetch_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(and_fetch_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(xor_fetch_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(or_fetch_,N), (T *mptr, T, int)); \
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DECLARE_1(T, C2(nand_fetch_,N), (T *mptr, T, int))
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/* All sized operations are implemented in hidden functions prefixed with
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"libat_". These are either renamed or aliased to the expected prefix
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of "__atomic". Some amount of renaming is required to avoid hiding or
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conflicting with the builtins of the same name, but this additional
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use of hidden symbols (where appropriate) avoids unnecessary PLT entries
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on relevant targets. */
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#if IFUNC_ALT
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# define MAN(X) ASMNAME(C4(libat_,X,_i,IFUNC_ALT)) HIDDEN
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#elif defined(HAVE_ATTRIBUTE_ALIAS)
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# define MAN(X) HIDDEN
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#else
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# define MAN(X) ASMNAME(C2(__atomic_,X))
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#endif
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#if !defined(N) && HAVE_IFUNC
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# define DECLARE_1(RET,NAME,ARGS) \
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RET C2(libat_,NAME) ARGS MAN(NAME); \
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RET C2(ifunc_,NAME) ARGS ASMNAME(C2(__atomic_,NAME))
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#else
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# define DECLARE_1(RET,NAME,ARGS) RET C2(libat_,NAME) ARGS MAN(NAME)
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#endif
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/* Prefix to use when calling internal, possibly ifunc'ed functions. */
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#if HAVE_IFUNC
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# define local_ ifunc_
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#else
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# define local_ libat_
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#endif
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DECLARE_ALL_SIZED(1);
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DECLARE_ALL_SIZED(2);
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DECLARE_ALL_SIZED(4);
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DECLARE_ALL_SIZED(8);
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DECLARE_ALL_SIZED(16);
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#undef DECLARE_1
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#undef DECLARE_ALL_SIZED
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#undef DECLARE_ALL_SIZED_
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/* And the generic sized versions. */
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void libat_load (size_t, void *, void *, int) MAN(load);
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void libat_store (size_t, void *, void *, int) MAN(store);
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void libat_exchange (size_t, void *, void *, void *, int) MAN(exchange);
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bool libat_compare_exchange (size_t, void *, void *, void *, int, int)
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MAN(compare_exchange);
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bool libat_is_lock_free (size_t, void *) MAN(is_lock_free);
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#undef MAN
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#include <host-config.h>
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/* We don't have IFUNC_NCOND until after host-config.h. */
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#if !HAVE_IFUNC
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# define IFUNC_NCOND(N) 0
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#endif
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#if IFUNC_ALT
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# define EXPORT_ALIAS(X) /* exported symbol in non-alternate file */
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#elif defined(N) && IFUNC_NCOND(N)
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# if IFUNC_NCOND(N) == 1
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# define GEN_SELECTOR(X) \
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extern typeof(C2(libat_,X)) C3(libat_,X,_i1) HIDDEN; \
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static typeof(C2(libat_,X)) * C2(select_,X) (IFUNC_RESOLVER_ARGS) \
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{ \
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if (IFUNC_COND_1) \
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return C3(libat_,X,_i1); \
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return C2(libat_,X); \
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}
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# elif IFUNC_NCOND(N) == 2
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# define GEN_SELECTOR(X) \
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extern typeof(C2(libat_,X)) C3(libat_,X,_i1) HIDDEN; \
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extern typeof(C2(libat_,X)) C3(libat_,X,_i2) HIDDEN; \
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static typeof(C2(libat_,X)) * C2(select_,X) (IFUNC_RESOLVER_ARGS) \
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{ \
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if (IFUNC_COND_1) \
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return C3(libat_,X,_i1); \
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if (IFUNC_COND_2) \
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return C3(libat_,X,_i2); \
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return C2(libat_,X); \
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}
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# elif IFUNC_NCOND(N) == 3
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# define GEN_SELECTOR(X) \
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extern typeof(C2(libat_,X)) C3(libat_,X,_i1) HIDDEN; \
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extern typeof(C2(libat_,X)) C3(libat_,X,_i2) HIDDEN; \
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extern typeof(C2(libat_,X)) C3(libat_,X,_i3) HIDDEN; \
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static typeof(C2(libat_,X)) * C2(select_,X) (IFUNC_RESOLVER_ARGS) \
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{ \
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if (IFUNC_COND_1) \
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return C3(libat_,X,_i1); \
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if (IFUNC_COND_2) \
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return C3(libat_,X,_i2); \
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if (IFUNC_COND_3) \
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return C3(libat_,X,_i3); \
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return C2(libat_,X); \
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}
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# else
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# error "Unsupported number of ifunc alternatives."
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# endif
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# define EXPORT_ALIAS(X) \
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GEN_SELECTOR(X) \
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typeof(C2(libat_,X)) C2(ifunc_,X) \
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ASMNAME(C2(__atomic_,X)) \
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__attribute__((ifunc(S(C2(select_,X)))))
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#elif defined(HAVE_ATTRIBUTE_ALIAS)
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# define EXPORT_ALIAS(X) \
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extern typeof(C2(libat_,X)) C2(export_,X) \
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ASMNAME(C2(__atomic_,X)) \
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__attribute__((alias(S(C2(libat_,X)))))
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#else
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# define EXPORT_ALIAS(X) /* original symbol is exported */
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#endif
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#endif /* LIBATOMIC_H */
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