| 1 | |
|---|
| 2 | dnl Check if the target supports weak. |
|---|
| 3 | AC_DEFUN([GCC_CHECK_ATTRIBUTE_WEAK], [ |
|---|
| 4 | AC_CACHE_CHECK([whether the target supports weak], |
|---|
| 5 | ac_cv_have_attribute_weak, [ |
|---|
| 6 | weakref_m4_saved_CFLAGS="$CFLAGS" |
|---|
| 7 | CFLAGS="$CFLAGS -Werror" |
|---|
| 8 | AC_TRY_COMPILE([void __attribute__((weak)) foo(void) { }], |
|---|
| 9 | [], ac_cv_have_attribute_weak=yes, |
|---|
| 10 | ac_cv_have_attribute_weak=no) |
|---|
| 11 | CFLAGS="$weakref_m4_saved_CFLAGS"]) |
|---|
| 12 | if test x"$ac_cv_have_attribute_weak" = xyes; then |
|---|
| 13 | AC_DEFINE(HAVE_ATTRIBUTE_WEAK, 1, |
|---|
| 14 | [Define to 1 if the target supports __attribute__((weak)).]) |
|---|
| 15 | fi]) |
|---|
| 16 | |
|---|
| 17 | dnl Check whether weak refs work like the ELF ones. |
|---|
| 18 | dnl This means that the weak reference works without having to satify |
|---|
| 19 | dnl linkage for the item. |
|---|
| 20 | dnl There are targets (at least Darwin) where we have fully functional |
|---|
| 21 | dnl weakrefs at runtime, but must supply the referenced item at link time. |
|---|
| 22 | AC_DEFUN([GCC_CHECK_ELF_STYLE_WEAKREF], [ |
|---|
| 23 | AC_CACHE_CHECK([whether weak refs work like ELF], |
|---|
| 24 | ac_cv_have_elf_style_weakref, [ |
|---|
| 25 | weakref_m4_saved_CFLAGS="$CFLAGS" |
|---|
| 26 | case "${host}" in |
|---|
| 27 | *-apple-darwin*) CFLAGS="$CFLAGS -Wl,-undefined,dynamic_lookup" ;; |
|---|
| 28 | *) ;; |
|---|
| 29 | esac |
|---|
| 30 | AC_RUN_IFELSE([AC_LANG_SOURCE([[ |
|---|
| 31 | extern void fNotToBeFound(void) __attribute__((weak)); |
|---|
| 32 | int main () |
|---|
| 33 | { |
|---|
| 34 | if (fNotToBeFound) |
|---|
| 35 | return 1; |
|---|
| 36 | else |
|---|
| 37 | return 0; |
|---|
| 38 | } |
|---|
| 39 | ]])], ac_cv_have_elf_style_weakref=yes, ac_cv_have_elf_style_weakref=no, [ |
|---|
| 40 | case "${host}" in |
|---|
| 41 | *-apple-darwin[[89]]*) ac_cv_have_elf_style_weakref=no ;; |
|---|
| 42 | *) ac_cv_have_elf_style_weakref=yes;; |
|---|
| 43 | esac])CFLAGS="$weakref_m4_saved_CFLAGS"]) |
|---|
| 44 | if test x"$ac_cv_have_elf_style_weakref" = xyes; then |
|---|
| 45 | AC_DEFINE(HAVE_ELF_STYLE_WEAKREF, 1, [Define to 1 if target has a weakref that works like the ELF one.]) |
|---|
| 46 | fi]) |
|---|
| 47 | |
|---|
