diff options
Diffstat (limited to 'libstdc++-v3/acinclude.m4')
| -rw-r--r-- | libstdc++-v3/acinclude.m4 | 303 |
1 files changed, 106 insertions, 197 deletions
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index a0094c2..0fc74d0 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -3709,16 +3709,22 @@ AC_DEFUN([GLIBCXX_ENABLE_PCH], [ AC_SUBST(glibcxx_PCHFLAGS) ]) - dnl dnl Check for atomic builtins. dnl See: dnl http://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html dnl -dnl This checks to see if the host supports the compiler-generated -dnl builtins for atomic operations for various integral sizes. Note, this -dnl is intended to be an all-or-nothing switch, so all the atomic operations -dnl that are used should be checked. +dnl This checks to see if the host supports __atomic_fetch_add on _Atomic_word. +dnl +dnl We don't want libstdc++.so to depend on libatomic.so for basic +dnl functionality like library-internal reference counting. This means we +dnl should not use atomics for reference counting unless it can be done +dnl using native instructions and not by calling into libatomic. +dnl This policy could change if linking to libatomic.so becomes implicit. +dnl +dnl Defines: +dnl GLIBCXX_ATOMIC_WORD_BUILTINS - if atomic builtins should be used for +dnl increments and decrements of _Atomic_word. dnl dnl Note: dnl libgomp and libgfortran use a link test, see CHECK_SYNC_FETCH_AND_ADD. @@ -3728,7 +3734,7 @@ AC_DEFUN([GLIBCXX_ENABLE_ATOMIC_BUILTINS], [ AC_LANG_CPLUSPLUS old_CXXFLAGS="$CXXFLAGS" - # Do link tests if possible, instead asm tests, limited to some platforms + # Do link tests if possible, otherwise asm tests. Limited to some platforms # see discussion in PR target/40134, PR libstdc++/40133 and the thread # starting at http://gcc.gnu.org/ml/gcc-patches/2009-07/msg00322.html atomic_builtins_link_tests=no @@ -3741,223 +3747,59 @@ AC_DEFUN([GLIBCXX_ENABLE_ATOMIC_BUILTINS], [ esac fi - if test x$atomic_builtins_link_tests = xyes; then - - # Do link tests. + if test "$atomic_builtins_link_tests" = yes; then - CXXFLAGS="$CXXFLAGS -fno-exceptions" - - AC_CACHE_CHECK([for atomic builtins for bool], - glibcxx_cv_atomic_bool, [ - AC_TRY_LINK( - [ ], - [typedef bool atomic_type; - atomic_type c1; - atomic_type c2; - atomic_type c3(0); - // N.B. __atomic_fetch_add is not supported for bool. - __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL, - __ATOMIC_RELAXED); - __atomic_test_and_set(&c1, __ATOMIC_RELAXED); - __atomic_load_n(&c1, __ATOMIC_RELAXED); - ], - [glibcxx_cv_atomic_bool=yes], - [glibcxx_cv_atomic_bool=no]) - ]) - - AC_CACHE_CHECK([for atomic builtins for short], - glibcxx_cv_atomic_short, [ - AC_TRY_LINK( - [ ], - [typedef short atomic_type; - atomic_type c1; - atomic_type c2; - atomic_type c3(0); - __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED); - __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL, - __ATOMIC_RELAXED); - __atomic_test_and_set(&c1, __ATOMIC_RELAXED); - __atomic_load_n(&c1, __ATOMIC_RELAXED); - ], - [glibcxx_cv_atomic_short=yes], - [glibcxx_cv_atomic_short=no]) - ]) + # Do link tests. - AC_CACHE_CHECK([for atomic builtins for int], - glibcxx_cv_atomic_int, [ - AC_TRY_LINK( - [ ], - [typedef int atomic_type; - atomic_type c1; - atomic_type c2; - atomic_type c3(0); - __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED); - __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL, - __ATOMIC_RELAXED); - __atomic_test_and_set(&c1, __ATOMIC_RELAXED); - __atomic_load_n(&c1, __ATOMIC_RELAXED); - ], - [glibcxx_cv_atomic_int=yes], - [glibcxx_cv_atomic_int=no]) - ]) + CXXFLAGS="$CXXFLAGS -fno-exceptions" - AC_CACHE_CHECK([for atomic builtins for long long], - glibcxx_cv_atomic_long_long, [ - AC_TRY_LINK( - [ ], - [typedef long long atomic_type; - atomic_type c1; - atomic_type c2; - atomic_type c3(0); - __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED); - __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL, - __ATOMIC_RELAXED); - __atomic_test_and_set(&c1, __ATOMIC_RELAXED); - __atomic_load_n(&c1, __ATOMIC_RELAXED); - ], - [glibcxx_cv_atomic_long_long=yes], - [glibcxx_cv_atomic_long_long=no]) - ]) + AC_CACHE_CHECK([for atomic builtins for _Atomic_word], + glibcxx_cv_atomic_word, + [AC_TRY_LINK([#include "${glibcxx_srcdir}/config/$atomic_word_dir/atomic_word.h"], + [_Atomic_word a = 0, b; + b = __atomic_fetch_add(&a, 1, __ATOMIC_ACQ_REL);], + [glibcxx_cv_atomic_word=yes], + [glibcxx_cv_atomic_word=no])]) else + # Do asm tests. - # Do asm tests. - - # Compile unoptimized. - CXXFLAGS='-O0 -S' - - # Fake what AC_TRY_COMPILE does. - - cat > conftest.$ac_ext << EOF -[#]line __oline__ "configure" -int main() -{ - typedef bool atomic_type; - atomic_type c1; - atomic_type c2; - atomic_type c3(0); - // N.B. __atomic_fetch_add is not supported for bool. - __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL, - __ATOMIC_RELAXED); - __atomic_test_and_set(&c1, __ATOMIC_RELAXED); - __atomic_load_n(&c1, __ATOMIC_RELAXED); - - return 0; -} -EOF - - AC_MSG_CHECKING([for atomic builtins for bool]) - if AC_TRY_EVAL(ac_compile); then - if grep __atomic_ conftest.s >/dev/null 2>&1 ; then - glibcxx_cv_atomic_bool=no - else - glibcxx_cv_atomic_bool=yes - fi - fi - AC_MSG_RESULT($glibcxx_cv_atomic_bool) - rm -f conftest* - - cat > conftest.$ac_ext << EOF -[#]line __oline__ "configure" -int main() -{ - typedef short atomic_type; - atomic_type c1; - atomic_type c2; - atomic_type c3(0); - __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED); - __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL, - __ATOMIC_RELAXED); - __atomic_test_and_set(&c1, __ATOMIC_RELAXED); - __atomic_load_n(&c1, __ATOMIC_RELAXED); - - return 0; -} -EOF - - AC_MSG_CHECKING([for atomic builtins for short]) - if AC_TRY_EVAL(ac_compile); then - if grep __atomic_ conftest.s >/dev/null 2>&1 ; then - glibcxx_cv_atomic_short=no - else - glibcxx_cv_atomic_short=yes - fi - fi - AC_MSG_RESULT($glibcxx_cv_atomic_short) - rm -f conftest* - - cat > conftest.$ac_ext << EOF -[#]line __oline__ "configure" -int main() -{ - // NB: _Atomic_word not necessarily int. - typedef int atomic_type; - atomic_type c1; - atomic_type c2; - atomic_type c3(0); - __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED); - __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL, - __ATOMIC_RELAXED); - __atomic_test_and_set(&c1, __ATOMIC_RELAXED); - __atomic_load_n(&c1, __ATOMIC_RELAXED); + # Compile unoptimized. + CXXFLAGS='-O0 -S' - return 0; -} -EOF - - AC_MSG_CHECKING([for atomic builtins for int]) - if AC_TRY_EVAL(ac_compile); then - if grep __atomic_ conftest.s >/dev/null 2>&1 ; then - glibcxx_cv_atomic_int=no - else - glibcxx_cv_atomic_int=yes - fi - fi - AC_MSG_RESULT($glibcxx_cv_atomic_int) - rm -f conftest* + # Fake what AC_TRY_COMPILE does. cat > conftest.$ac_ext << EOF [#]line __oline__ "configure" +[#]include "${glibcxx_srcdir}/config/$atomic_word_dir/atomic_word.h" int main() { - typedef long long atomic_type; - atomic_type c1; - atomic_type c2; - atomic_type c3(0); - __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED); - __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL, - __ATOMIC_RELAXED); - __atomic_test_and_set(&c1, __ATOMIC_RELAXED); - __atomic_load_n(&c1, __ATOMIC_RELAXED); - - return 0; + _Atomic_word a = 0, b; + b = __atomic_fetch_add(&a, 1, __ATOMIC_ACQ_REL); } EOF - AC_MSG_CHECKING([for atomic builtins for long long]) + AC_MSG_CHECKING([for atomic builtins for _Atomic_word]) if AC_TRY_EVAL(ac_compile); then if grep __atomic_ conftest.s >/dev/null 2>&1 ; then - glibcxx_cv_atomic_long_long=no + glibcxx_cv_atomic_word=no else - glibcxx_cv_atomic_long_long=yes + glibcxx_cv_atomic_word=yes fi fi - AC_MSG_RESULT($glibcxx_cv_atomic_long_long) + AC_MSG_RESULT($glibcxx_cv_atomic_word) rm -f conftest* - fi CXXFLAGS="$old_CXXFLAGS" AC_LANG_RESTORE - # Set atomicity_dir to builtins if all but the long long test above passes, + # Set atomicity_dir to builtins if the test above passes, # or if the builtins were already chosen (e.g. by configure.host). - if { test "$glibcxx_cv_atomic_bool" = yes \ - && test "$glibcxx_cv_atomic_short" = yes \ - && test "$glibcxx_cv_atomic_int" = yes; } \ + if test "$glibcxx_cv_atomic_word" = yes \ || test "$atomicity_dir" = "cpu/generic/atomicity_builtins"; then - AC_DEFINE(_GLIBCXX_ATOMIC_BUILTINS, 1, - [Define if the compiler supports C++11 atomics.]) + AC_DEFINE(_GLIBCXX_ATOMIC_WORD_BUILTINS, 1, + [Define if the compiler supports native atomics for _Atomic_word.]) atomicity_dir=cpu/generic/atomicity_builtins fi @@ -5448,8 +5290,75 @@ AC_DEFUN([GLIBCXX_ENABLE_BACKTRACE], [ BACKTRACE_CPPFLAGS="-D_GNU_SOURCE" - # libbacktrace only needs atomics for int, which we've already tested - if test "$glibcxx_cv_atomic_int" = "yes"; then + GLIBCXX_LANG_PUSH + + # libbacktrace's own configure.ac only tests atomics for int, + # but the code actually uses atomics for size_t and pointers as well. + if test "$atomic_builtins_link_tests" = yes; then + + CXXFLAGS='-O0' + + AC_CACHE_CHECK([for atomic builtins for libbacktrace], + glibcxx_cv_libbacktrace_atomics, + [AC_TRY_LINK([], [ + int i = 0; + int* p = &i; + size_t s = 0; + // backtrace_atomic_load_pointer + void* vp = __atomic_load_n(&p, __ATOMIC_ACQUIRE); + // backtrace_atomic_load_int + int i2 = __atomic_load_n(&i, __ATOMIC_ACQUIRE); + // backtrace_atomic_store_pointer + __atomic_store_n(&p, &i, __ATOMIC_RELEASE); + // backtrace_atomic_store_size_t + __atomic_store_n(&s, s, __ATOMIC_RELEASE); + // backtrace_atomic_store_int + __atomic_store_n(&i, i, __ATOMIC_RELEASE); + ], + [glibcxx_cv_libbacktrace_atomics=yes], + [glibcxx_cv_libbacktrace_atomics=no])]) + + else + # Do asm tests. + + CXXFLAGS='-O0 -S' + + cat > conftest.$ac_ext << EOF +[#]line __oline__ "configure" +[#]include <stddef.h> +int main() +{ + int i = 0; + int* p = &i; + size_t s = 0; + // backtrace_atomic_load_pointer + void* vp = __atomic_load_n(&p, __ATOMIC_ACQUIRE); + // backtrace_atomic_load_int + int i2 = __atomic_load_n(&i, __ATOMIC_ACQUIRE); + // backtrace_atomic_store_pointer + __atomic_store_n(&p, &i, __ATOMIC_RELEASE); + // backtrace_atomic_store_size_t + __atomic_store_n(&s, s, __ATOMIC_RELEASE); + // backtrace_atomic_store_int + __atomic_store_n(&i, i, __ATOMIC_RELEASE); +} +EOF + + AC_MSG_CHECKING([for atomic builtins for libbacktrace]) + if AC_TRY_EVAL(ac_compile); then + if grep __atomic_ conftest.s >/dev/null 2>&1 ; then + glibcxx_cv_libbacktrace_atomics=no + else + glibcxx_cv_libbacktrace_atomics=yes + fi + fi + AC_MSG_RESULT($glibcxx_cv_libbacktrace_atomics) + rm -f conftest* + fi + + GLIBCXX_LANG_POP + + if test "$glibcxx_cv_libbacktrace_atomics" = yes; then BACKTRACE_CPPFLAGS="$BACKTRACE_CPPFLAGS -DHAVE_ATOMIC_FUNCTIONS=1" fi |