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build(atomic): detect GCC/Clang __atomic builtins, enabling native atomics #32

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Merged
gburd merged 1 commit into from
Jun 25, 2026
Merged

build(atomic): detect GCC/Clang __atomic builtins, enabling native atomics #32

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35 changes: 33 additions & 2 deletions dist/aclocal/mutex.m4
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Original file line number Diff line number Diff line change
Expand Up @@ -1010,6 +1010,8 @@ AH_TEMPLATE(HAVE_ATOMIC_SOLARIS,
[Define to 1 to use Solaris library routes for atomic operations.])
AH_TEMPLATE(HAVE_ATOMIC_BUILTINS,
[Define to 1 to use GCC __atomic_* builtins for atomic operations.])
AH_TEMPLATE(HAVE_ATOMIC_GCC_BUILTIN,
[Define to 1 when the GCC/Clang __atomic_* builtin tier is selected.])
AH_TEMPLATE(HAVE_SYNC_BUILTINS,
[Define to 1 to use GCC __sync_* builtins for atomic operations.])
AH_TEMPLATE(HAVE_ATOMIC_AARCH64,
Expand All @@ -1029,12 +1031,25 @@ if test "$db_cv_mingw" = yes; then
db_cv_atomic=mingw
fi

if test "$db_cv_atomic" = no; then
AC_LINK_IFELSE([AC_LANG_PROGRAM([[
#include <stdint.h>]], [[
uint32_t val32 = 1;
uint32_t exp32 = 1;
intptr_t valp = 1;
intptr_t expp = 1;
__atomic_add_fetch(&val32, 1, __ATOMIC_SEQ_CST);
__atomic_compare_exchange_n(&val32, &exp32, 2, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
__atomic_compare_exchange_n(&valp, &expp, 2, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
]])], [db_cv_atomic="gcc/__atomic"])
fi

if test "$db_cv_atomic" = no; then
AC_COMPILE_IFELSE([AC_LANG_PROGRAM(, [[
#if ((defined(i386) || defined(__i386__)) && defined(__GNUC__))
exit(0);
(void)0;
#elif ((defined(x86_64) || defined(__x86_64__)) && defined(__GNUC__))
exit(0);
(void)0;
#else
FAIL TO COMPILE/LINK
#endif
Expand All @@ -1053,6 +1068,12 @@ fi
])

case "$db_cv_atomic" in
gcc/__atomic)
AC_DEFINE(HAVE_ATOMIC_SUPPORT)
AC_DEFINE(HAVE_ATOMIC_BUILTINS)
AC_DEFINE(HAVE_ATOMIC_GCC_BUILTIN)
;;

x86/gcc-assembly)
AC_DEFINE(HAVE_ATOMIC_SUPPORT)
AC_DEFINE(HAVE_ATOMIC_X86_GCC_ASSEMBLY)
Expand Down Expand Up @@ -1085,6 +1106,16 @@ fi
AC_CACHE_CHECK([for 64-bit atomic operations], db_cv_atomic_64bit, [
db_cv_atomic_64bit=no
case "$db_cv_atomic" in
gcc/__atomic)
AC_LINK_IFELSE([AC_LANG_PROGRAM([[
#include <stdint.h>]], [[
int64_t val = 1;
int64_t exp = 1;
__atomic_add_fetch(&val, 1, __ATOMIC_SEQ_CST);
__atomic_sub_fetch(&val, 1, __ATOMIC_SEQ_CST);
__atomic_compare_exchange_n(&val, &exp, 2, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
]])], [db_cv_atomic_64bit=yes])
;;
x86/gcc-assembly)
AC_LINK_IFELSE([AC_LANG_PROGRAM([[
#include <stdint.h>]], [[
Expand Down
3 changes: 3 additions & 0 deletions dist/config.hin
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,9 @@
/* Define to 1 to use GCC __atomic_* builtins for atomic operations. */
#undef HAVE_ATOMIC_BUILTINS

/* Define to 1 when the GCC/Clang __atomic_* builtin tier is selected. */
#undef HAVE_ATOMIC_GCC_BUILTIN

/* Define to 1 to use Solaris library routes for atomic operations. */
#undef HAVE_ATOMIC_SOLARIS

Expand Down
69 changes: 67 additions & 2 deletions dist/configure
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Original file line number Diff line number Diff line change
Expand Up @@ -25809,6 +25809,7 @@ esac




{ printf '%s\n' "$as_me:${as_lineno-$LINENO}: checking for atomic operations" >&5
printf %s "checking for atomic operations... " >&6; }
if test ${db_cv_atomic+y}
Expand All @@ -25827,6 +25828,35 @@ if test "$db_cv_mingw" = yes; then
db_cv_atomic=mingw
fi

if test "$db_cv_atomic" = no; then
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */

#include <stdint.h>
int
main (void)
{

uint32_t val32 = 1;
uint32_t exp32 = 1;
intptr_t valp = 1;
intptr_t expp = 1;
__atomic_add_fetch(&val32, 1, __ATOMIC_SEQ_CST);
__atomic_compare_exchange_n(&val32, &exp32, 2, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
__atomic_compare_exchange_n(&valp, &expp, 2, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);

;
return 0;
}
_ACEOF
if ac_fn_c_try_link "$LINENO"
then :
db_cv_atomic="gcc/__atomic"
fi
rm -f core conftest.err conftest.$ac_objext conftest.beam \
conftest$ac_exeext conftest.$ac_ext
fi

if test "$db_cv_atomic" = no; then
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
Expand All @@ -25836,9 +25866,9 @@ main (void)
{

#if ((defined(i386) || defined(__i386__)) && defined(__GNUC__))
exit(0);
(void)0;
#elif ((defined(x86_64) || defined(__x86_64__)) && defined(__GNUC__))
exit(0);
(void)0;
#else
FAIL TO COMPILE/LINK
#endif
Expand Down Expand Up @@ -25886,6 +25916,15 @@ fi
printf '%s\n' "$db_cv_atomic" >&6; }

case "$db_cv_atomic" in
gcc/__atomic)
printf '%s\n' "#define HAVE_ATOMIC_SUPPORT 1" >>confdefs.h

printf '%s\n' "#define HAVE_ATOMIC_BUILTINS 1" >>confdefs.h

printf '%s\n' "#define HAVE_ATOMIC_GCC_BUILTIN 1" >>confdefs.h

;;

x86/gcc-assembly)
printf '%s\n' "#define HAVE_ATOMIC_SUPPORT 1" >>confdefs.h

Expand Down Expand Up @@ -25958,6 +25997,32 @@ else case e in #(
e)
db_cv_atomic_64bit=no
case "$db_cv_atomic" in
gcc/__atomic)
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */

#include <stdint.h>
int
main (void)
{

int64_t val = 1;
int64_t exp = 1;
__atomic_add_fetch(&val, 1, __ATOMIC_SEQ_CST);
__atomic_sub_fetch(&val, 1, __ATOMIC_SEQ_CST);
__atomic_compare_exchange_n(&val, &exp, 2, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);

;
return 0;
}
_ACEOF
if ac_fn_c_try_link "$LINENO"
then :
db_cv_atomic_64bit=yes
fi
rm -f core conftest.err conftest.$ac_objext conftest.beam \
conftest$ac_exeext conftest.$ac_ext
;;
x86/gcc-assembly)
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
Expand Down
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