On some platforms, gcc generates library calls when __atomic_* functions are used, but does not link the required library automatically. Detect this and add the library when needed.
This change was tested on armel (library was added) and on x86_64 (was not, as expected). Fixes: 8915f0c0 "util: use GCC atomic intrinsics with explicit memory model" Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102573 Signed-off-by: Grazvydas Ignotas <nota...@gmail.com> --- configure.ac | 13 +++++++++++++ src/util/Makefile.am | 3 ++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/configure.ac b/configure.ac index 605c9b4..b46f29d 100644 --- a/configure.ac +++ b/configure.ac @@ -377,12 +377,25 @@ int main() { int n; return __atomic_load_n(&n, __ATOMIC_ACQUIRE); }]])], GCC_ATOMIC_BUILTINS_SUPPORTED=1) if test "x$GCC_ATOMIC_BUILTINS_SUPPORTED" = x1; then DEFINES="$DEFINES -DUSE_GCC_ATOMIC_BUILTINS" + dnl On some platforms, new-style atomics need a helper library + AC_MSG_CHECKING(whether -latomic is needed) + AC_LINK_IFELSE([AC_LANG_SOURCE([[ + #include <stdint.h> + uint64_t v; + int main() { + return (int)__atomic_load_n(&v, __ATOMIC_ACQUIRE); + }]])], GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC=no, GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC=yes) + AC_MSG_RESULT($GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC) + if test "x$GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC" = xyes; then + LIBATOMIC_LIBS="-latomic" + fi fi AM_CONDITIONAL([GCC_ATOMIC_BUILTINS_SUPPORTED], [test x$GCC_ATOMIC_BUILTINS_SUPPORTED = x1]) +AC_SUBST([LIBATOMIC_LIBS]) dnl Check if host supports 64-bit atomics dnl note that lack of support usually results in link (not compile) error AC_MSG_CHECKING(whether __sync_add_and_fetch_8 is supported) AC_LINK_IFELSE([AC_LANG_SOURCE([[ diff --git a/src/util/Makefile.am b/src/util/Makefile.am index 9885bbe..c37afff 100644 --- a/src/util/Makefile.am +++ b/src/util/Makefile.am @@ -46,11 +46,12 @@ libmesautil_la_SOURCES = \ $(MESA_UTIL_FILES) \ $(MESA_UTIL_GENERATED_FILES) libmesautil_la_LIBADD = \ $(CLOCK_LIB) \ - $(ZLIB_LIBS) + $(ZLIB_LIBS) \ + $(LIBATOMIC_LIBS) libxmlconfig_la_SOURCES = $(XMLCONFIG_FILES) libxmlconfig_la_CFLAGS = \ $(DEFINES) \ -I$(top_srcdir)/include \ -- 2.7.4 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
