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asm: remove support for __sync built-in atomics
This commit removes the unsupported __sync built-in atomics in favor of the GCC built-ins. The priority order (if not modified by configure flags) is: C11, custom atomics (opal/include/opal/sys/*), then GCC built-ins. Signed-off-by: Nathan Hjelm <hjelmn@google.com>
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+72
-297
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5 files changed

+72
-297
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‎config/opal_config_asm.m4‎

Lines changed: 71 additions & 107 deletions
Original file line numberDiff line numberDiff line change
@@ -285,37 +285,6 @@ AC_DEFUN([OPAL_CHECK_SYNC_BUILTIN_CSWAP_INT128], [
285285
OPAL_VAR_SCOPE_POP
286286
])
287287

288-
AC_DEFUN([OPAL_CHECK_SYNC_BUILTINS], [
289-
AC_MSG_CHECKING([for __sync builtin atomics])
290-
291-
AC_TRY_LINK([long tmp;], [__sync_synchronize();
292-
__sync_bool_compare_and_swap(&tmp, 0, 1);
293-
__sync_add_and_fetch(&tmp, 1);],
294-
[AC_MSG_RESULT([yes])
295-
$1],
296-
[AC_MSG_RESULT([no])
297-
$2])
298-
299-
AC_MSG_CHECKING([for 64-bit __sync builtin atomics])
300-
301-
AC_TRY_LINK([
302-
#include <stdint.h>
303-
uint64_t tmp;], [
304-
__sync_bool_compare_and_swap(&tmp, 0, 1);
305-
__sync_add_and_fetch(&tmp, 1);],
306-
[AC_MSG_RESULT([yes])
307-
opal_asm_sync_have_64bit=1],
308-
[AC_MSG_RESULT([no])
309-
opal_asm_sync_have_64bit=0])
310-
311-
AC_DEFINE_UNQUOTED([OPAL_ASM_SYNC_HAVE_64BIT],[$opal_asm_sync_have_64bit],
312-
[Whether 64-bit is supported by the __sync builtin atomics])
313-
314-
# Check for 128-bit support
315-
OPAL_CHECK_SYNC_BUILTIN_CSWAP_INT128
316-
])
317-
318-
319288
AC_DEFUN([OPAL_CHECK_GCC_BUILTIN_CSWAP_INT128], [
320289
OPAL_VAR_SCOPE_PUSH([atomic_compare_exchange_n_128_result atomic_compare_exchange_n_128_CFLAGS_save atomic_compare_exchange_n_128_LIBS_save])
321290
@@ -361,9 +330,10 @@ AC_DEFUN([OPAL_CHECK_GCC_BUILTIN_CSWAP_INT128], [
361330
])
362331

363332
AC_DEFUN([OPAL_CHECK_GCC_ATOMIC_BUILTINS], [
364-
AC_MSG_CHECKING([for __atomic builtin atomics])
333+
if test -z "$opal_cv_have___atomic" ; then
334+
AC_MSG_CHECKING([for 32-bit GCC built-in atomics])
365335
366-
AC_TRY_LINK([
336+
AC_TRY_LINK([
367337
#include <stdint.h>
368338
uint32_t tmp, old = 0;
369339
uint64_t tmp64, old64 = 0;], [
@@ -372,13 +342,39 @@ __atomic_compare_exchange_n(&tmp, &old, 1, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED
372342
__atomic_add_fetch(&tmp, 1, __ATOMIC_RELAXED);
373343
__atomic_compare_exchange_n(&tmp64, &old64, 1, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
374344
__atomic_add_fetch(&tmp64, 1, __ATOMIC_RELAXED);],
375-
[AC_MSG_RESULT([yes])
376-
$1],
377-
[AC_MSG_RESULT([no])
378-
$2])
345+
[opal_cv_have___atomic=yes],
346+
[opal_cv_have___atomic=no])
347+
348+
AC_MSG_RESULT([$opal_cv_have___atomic])
349+
350+
if test $opal_cv_have___atomic = "yes" ; then
351+
AC_MSG_CHECKING([for 64-bit GCC built-in atomics])
379352
380-
# Check for 128-bit support
381-
OPAL_CHECK_GCC_BUILTIN_CSWAP_INT128
353+
AC_TRY_LINK([
354+
#include <stdint.h>
355+
uint64_t tmp64, old64 = 0;], [
356+
__atomic_compare_exchange_n(&tmp64, &old64, 1, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
357+
__atomic_add_fetch(&tmp64, 1, __ATOMIC_RELAXED);],
358+
[opal_cv_have___atomic_64=yes],
359+
[opal_cv_have___atomic_64=no])
360+
361+
AC_MSG_RESULT([$opal_cv_have___atomic_64])
362+
363+
if test $opal_cv_have___atomic_64 = "yes" ; then
364+
AC_MSG_CHECKING([if 64-bit GCC built-in atomics are lock-free])
365+
AC_RUN_IFELSE([AC_LANG_PROGRAM([], [if (!__atomic_is_lock_free (8, 0)) { return 1; }])],
366+
[AC_MSG_RESULT([yes])],
367+
[AC_MSG_RESULT([no])
368+
opal_cv_have___atomic_64=no],
369+
[AC_MSG_RESULT([cannot test -- assume yes (cross compiling)])])
370+
fi
371+
else
372+
opal_cv_have___atomic_64=no
373+
fi
374+
375+
# Check for 128-bit support
376+
OPAL_CHECK_GCC_BUILTIN_CSWAP_INT128
377+
fi
382378
])
383379

384380
AC_DEFUN([OPAL_CHECK_C11_CSWAP_INT128], [
@@ -425,28 +421,6 @@ AC_DEFUN([OPAL_CHECK_C11_CSWAP_INT128], [
425421
OPAL_VAR_SCOPE_POP
426422
])
427423

428-
AC_DEFUN([OPAL_CHECK_GCC_ATOMIC_BUILTINS], [
429-
AC_MSG_CHECKING([for __atomic builtin atomics])
430-
431-
AC_TRY_LINK([
432-
#include <stdint.h>
433-
uint32_t tmp, old = 0;
434-
uint64_t tmp64, old64 = 0;], [
435-
__atomic_thread_fence(__ATOMIC_SEQ_CST);
436-
__atomic_compare_exchange_n(&tmp, &old, 1, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
437-
__atomic_add_fetch(&tmp, 1, __ATOMIC_RELAXED);
438-
__atomic_compare_exchange_n(&tmp64, &old64, 1, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
439-
__atomic_add_fetch(&tmp64, 1, __ATOMIC_RELAXED);],
440-
[AC_MSG_RESULT([yes])
441-
$1],
442-
[AC_MSG_RESULT([no])
443-
$2])
444-
445-
# Check for 128-bit support
446-
OPAL_CHECK_GCC_BUILTIN_CSWAP_INT128
447-
])
448-
449-
450424
dnl #################################################################
451425
dnl
452426
dnl OPAL_CHECK_ASM_TEXT
@@ -1142,24 +1116,25 @@ AC_DEFUN([OPAL_CONFIG_ASM],[
11421116
11431117
AC_ARG_ENABLE([builtin-atomics],
11441118
[AC_HELP_STRING([--enable-builtin-atomics],
1145-
[Enable use of __sync builtin atomics (default: disabled)])])
1119+
[Enable use of GCC built-in atomics (default: autodetect)])])
11461120
11471121
OPAL_CHECK_C11_CSWAP_INT128
1122+
opal_cv_asm_builtin="BUILTIN_NO"
1123+
OPAL_CHECK_GCC_ATOMIC_BUILTINS
11481124
11491125
if test "x$enable_c11_atomics" != "xno" && test "$opal_cv_c11_supported" = "yes" ; then
11501126
opal_cv_asm_builtin="BUILTIN_C11"
11511127
OPAL_CHECK_C11_CSWAP_INT128
11521128
elif test "x$enable_c11_atomics" = "xyes"; then
11531129
AC_MSG_WARN([C11 atomics were requested but are not supported])
11541130
AC_MSG_ERROR([Cannot continue])
1155-
else
1156-
opal_cv_asm_builtin="BUILTIN_NO"
1157-
AS_IF([test "$opal_cv_asm_builtin" = "BUILTIN_NO" && test "$enable_builtin_atomics" = "yes"],
1158-
[OPAL_CHECK_GCC_ATOMIC_BUILTINS([opal_cv_asm_builtin="BUILTIN_GCC"], [])])
1159-
AS_IF([test "$opal_cv_asm_builtin" = "BUILTIN_NO" && test "$enable_builtin_atomics" = "yes"],
1160-
[OPAL_CHECK_SYNC_BUILTINS([opal_cv_asm_builtin="BUILTIN_SYNC"], [])])
1161-
AS_IF([test "$opal_cv_asm_builtin" = "BUILTIN_NO" && test "$enable_builtin_atomics" = "yes"],
1162-
[AC_MSG_ERROR([__sync builtin atomics requested but not found.])])
1131+
elif test "$enable_builtin_atomics" = "yes" ; then
1132+
if test $opal_cv_have___atomic = "yes" ; then
1133+
opal_cv_asm_builtin="BUILTIN_GCC"
1134+
else
1135+
AC_MSG_WARN([GCC built-in atomics requested but not found.])
1136+
AC_MSG_ERROR([Cannot continue])
1137+
fi
11631138
fi
11641139
11651140
OPAL_CHECK_ASM_PROC
@@ -1176,7 +1151,12 @@ AC_DEFUN([OPAL_CONFIG_ASM],[
11761151
# find our architecture for purposes of assembly stuff
11771152
opal_cv_asm_arch="UNSUPPORTED"
11781153
OPAL_GCC_INLINE_ASSIGN=""
1179-
OPAL_ASM_SUPPORT_64BIT=0
1154+
if test "$opal_cv_have___atomic_64" ; then
1155+
OPAL_ASM_SUPPORT_64BIT=1
1156+
else
1157+
OPAL_ASM_SUPPORT_64BIT=0
1158+
fi
1159+
11801160
case "${host}" in
11811161
x86_64-*x32)
11821162
opal_cv_asm_arch="X86_64"
@@ -1198,17 +1178,13 @@ AC_DEFUN([OPAL_CONFIG_ASM],[
11981178
opal_cv_asm_arch="ARM64"
11991179
OPAL_ASM_SUPPORT_64BIT=1
12001180
OPAL_ASM_ARM_VERSION=8
1201-
AC_DEFINE_UNQUOTED([OPAL_ASM_ARM_VERSION], [$OPAL_ASM_ARM_VERSION],
1202-
[What ARM assembly version to use])
12031181
OPAL_GCC_INLINE_ASSIGN='"mov %0, #0" : "=&r"(ret)'
12041182
;;
12051183
12061184
armv7*|arm-*-linux-gnueabihf)
12071185
opal_cv_asm_arch="ARM"
12081186
OPAL_ASM_SUPPORT_64BIT=1
12091187
OPAL_ASM_ARM_VERSION=7
1210-
AC_DEFINE_UNQUOTED([OPAL_ASM_ARM_VERSION], [$OPAL_ASM_ARM_VERSION],
1211-
[What ARM assembly version to use])
12121188
OPAL_GCC_INLINE_ASSIGN='"mov %0, #0" : "=&r"(ret)'
12131189
;;
12141190
@@ -1217,8 +1193,6 @@ AC_DEFUN([OPAL_CONFIG_ASM],[
12171193
OPAL_ASM_SUPPORT_64BIT=0
12181194
OPAL_ASM_ARM_VERSION=6
12191195
CCASFLAGS="$CCASFLAGS -march=armv7-a"
1220-
AC_DEFINE_UNQUOTED([OPAL_ASM_ARM_VERSION], [$OPAL_ASM_ARM_VERSION],
1221-
[What ARM assembly version to use])
12221196
OPAL_GCC_INLINE_ASSIGN='"mov %0, #0" : "=&r"(ret)'
12231197
;;
12241198
@@ -1269,37 +1243,27 @@ AC_MSG_ERROR([Can not continue.])
12691243
;;
12701244
12711245
*)
1272-
OPAL_CHECK_SYNC_BUILTINS([opal_cv_asm_builtin="BUILTIN_SYNC"],
1273-
[AC_MSG_ERROR([No atomic primitives available for $host])])
1274-
;;
1246+
if test $opal_cv_have___atomic = "yes" ; then
1247+
opal_cv_asm_builtin="BUILTIN_GCC"
1248+
else
1249+
AC_MSG_ERROR([No atomic primitives available for $host])
1250+
fi
1251+
;;
12751252
esac
12761253
1277-
if test "x$OPAL_ASM_SUPPORT_64BIT" = "x1" && test "$opal_cv_asm_builtin" = "BUILTIN_SYNC" &&
1278-
test "$opal_asm_sync_have_64bit" = "0" ; then
1279-
# __sync builtins exist but do not implement 64-bit support. Fall back on inline asm.
1280-
opal_cv_asm_builtin="BUILTIN_NO"
1281-
fi
1254+
if ! test -z "$OPAL_ASM_ARM_VERSION" ; then
1255+
AC_DEFINE_UNQUOTED([OPAL_ASM_ARM_VERSION], [$OPAL_ASM_ARM_VERSION],
1256+
[What ARM assembly version to use])
1257+
fi
12821258
1283-
if test "$opal_cv_asm_builtin" = "BUILTIN_SYNC" || test "$opal_cv_asm_builtin" = "BUILTIN_GCC" ; then
1284-
AC_DEFINE([OPAL_C_GCC_INLINE_ASSEMBLY], [1],
1285-
[Whether C compiler supports GCC style inline assembly])
1286-
else
1287-
AC_DEFINE_UNQUOTED([OPAL_ASM_SUPPORT_64BIT],
1288-
[$OPAL_ASM_SUPPORT_64BIT],
1289-
[Whether we can do 64bit assembly operations or not. Should not be used outside of the assembly header files])
1290-
AC_SUBST([OPAL_ASM_SUPPORT_64BIT])
1291-
1292-
#
1293-
# figure out if we need any special function start / stop code
1294-
#
1295-
case $host_os in
1296-
aix*)
1297-
opal_asm_arch_config="aix"
1298-
;;
1299-
*)
1300-
opal_asm_arch_config="default"
1301-
;;
1302-
esac
1259+
if test "$opal_cv_asm_builtin" = "BUILTIN_GCC" ; then
1260+
AC_DEFINE([OPAL_C_GCC_INLINE_ASSEMBLY], [1],
1261+
[Whether C compiler supports GCC style inline assembly])
1262+
else
1263+
AC_DEFINE_UNQUOTED([OPAL_ASM_SUPPORT_64BIT],
1264+
[$OPAL_ASM_SUPPORT_64BIT],
1265+
[Whether we can do 64bit assembly operations or not. Should not be used outside of the assembly header files])
1266+
AC_SUBST([OPAL_ASM_SUPPORT_64BIT])
13031267
13041268
opal_cv_asm_inline_supported="no"
13051269
# now that we know our architecture, try to inline assemble
@@ -1330,7 +1294,7 @@ AC_MSG_ERROR([Can not continue.])
13301294
AC_DEFINE_UNQUOTED([OPAL_ASSEMBLY_FORMAT], ["$OPAL_ASSEMBLY_FORMAT"],
13311295
[Format of assembly file])
13321296
AC_SUBST([OPAL_ASSEMBLY_FORMAT])
1333-
fi # if opal_cv_asm_builtin = BUILTIN_SYNC
1297+
fi # if opal_cv_asm_builtin = BUILTIN_GCC
13341298
13351299
result="OPAL_$opal_cv_asm_arch"
13361300
OPAL_ASSEMBLY_ARCH="$opal_cv_asm_arch"
@@ -1388,7 +1352,7 @@ AC_DEFUN([OPAL_ASM_FIND_FILE], [
13881352
AC_REQUIRE([AC_PROG_GREP])
13891353
AC_REQUIRE([AC_PROG_FGREP])
13901354
1391-
if test "$opal_cv_asm_arch" != "WINDOWS" && test "$opal_cv_asm_builtin" != "BUILTIN_SYNC" && test "$opal_cv_asm_builtin" != "BUILTIN_GCC" && test "$opal_cv_asm_builtin" != "BUILTIN_OSX" && test "$opal_cv_asm_inline_arch" = "no" ; then
1355+
if test "$opal_cv_asm_arch" != "WINDOWS" && test "$opal_cv_asm_builtin" != "BUILTIN_GCC" && test "$opal_cv_asm_builtin" != "BUILTIN_OSX" && test "$opal_cv_asm_inline_arch" = "no" ; then
13921356
AC_MSG_ERROR([no atomic support available. exiting])
13931357
else
13941358
# On windows with VC++, atomics are done with compiler primitives

‎opal/include/opal/sys/Makefile.am‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -15,6 +15,7 @@
1515
# reserved.
1616
# Copyright (c) 2017 Research Organization for Information Science
1717
# and Technology (RIST). All rights reserved.
18+
# Copyright (c) 2020 Google, LLC. All rights reserved.
1819
# $COPYRIGHT$
1920
#
2021
# Additional copyrights may follow
@@ -38,5 +39,4 @@ include opal/sys/arm64/Makefile.am
3839
include opal/sys/ia32/Makefile.am
3940
include opal/sys/powerpc/Makefile.am
4041
include opal/sys/sparcv9/Makefile.am
41-
include opal/sys/sync_builtin/Makefile.am
4242
include opal/sys/gcc_builtin/Makefile.am

‎opal/include/opal/sys/architecture.h‎

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -41,7 +41,6 @@
4141
#define OPAL_SPARCV9_64 0062
4242
#define OPAL_ARM 0100
4343
#define OPAL_ARM64 0101
44-
#define OPAL_BUILTIN_SYNC 0200
4544
#define OPAL_BUILTIN_GCC 0202
4645
#define OPAL_BUILTIN_NO 0203
4746
#define OPAL_BUILTIN_C11 0204

‎opal/include/opal/sys/sync_builtin/Makefile.am‎

Lines changed: 0 additions & 23 deletions
This file was deleted.

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