| [444] | 1 | |
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| 2 | dnl Check if the target supports weak. |
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| 3 | AC_DEFUN([GCC_CHECK_ATTRIBUTE_WEAK], [ |
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| 4 | AC_CACHE_CHECK([whether the target supports weak], |
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| 5 | ac_cv_have_attribute_weak, [ |
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| 6 | weakref_m4_saved_CFLAGS="$CFLAGS" |
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| 7 | CFLAGS="$CFLAGS -Werror" |
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| 8 | AC_TRY_COMPILE([void __attribute__((weak)) foo(void) { }], |
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| 9 | [], ac_cv_have_attribute_weak=yes, |
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| 10 | ac_cv_have_attribute_weak=no) |
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| 11 | CFLAGS="$weakref_m4_saved_CFLAGS"]) |
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| 12 | if test x"$ac_cv_have_attribute_weak" = xyes; then |
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| 13 | AC_DEFINE(HAVE_ATTRIBUTE_WEAK, 1, |
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| 14 | [Define to 1 if the target supports __attribute__((weak)).]) |
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| 15 | fi]) |
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| 16 | |
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| 17 | dnl Check whether weak refs work like the ELF ones. |
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| 18 | dnl This means that the weak reference works without having to satify |
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| 19 | dnl linkage for the item. |
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| 20 | dnl There are targets (at least Darwin) where we have fully functional |
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| 21 | dnl weakrefs at runtime, but must supply the referenced item at link time. |
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| 22 | AC_DEFUN([GCC_CHECK_ELF_STYLE_WEAKREF], [ |
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| 23 | AC_CACHE_CHECK([whether weak refs work like ELF], |
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| 24 | ac_cv_have_elf_style_weakref, [ |
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| 25 | weakref_m4_saved_CFLAGS="$CFLAGS" |
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| 26 | case "${host}" in |
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| 27 | *-apple-darwin*) CFLAGS="$CFLAGS -Wl,-undefined,dynamic_lookup" ;; |
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| 28 | *) ;; |
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| 29 | esac |
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| 30 | AC_RUN_IFELSE([AC_LANG_SOURCE([[ |
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| 31 | extern void fNotToBeFound(void) __attribute__((weak)); |
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| 32 | int main () |
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| 33 | { |
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| 34 | if (fNotToBeFound) |
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| 35 | return 1; |
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| 36 | else |
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| 37 | return 0; |
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| 38 | } |
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| 39 | ]])], ac_cv_have_elf_style_weakref=yes, ac_cv_have_elf_style_weakref=no, [ |
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| 40 | case "${host}" in |
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| 41 | *-apple-darwin[[89]]*) ac_cv_have_elf_style_weakref=no ;; |
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| 42 | *) ac_cv_have_elf_style_weakref=yes;; |
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| 43 | esac])CFLAGS="$weakref_m4_saved_CFLAGS"]) |
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| 44 | if test x"$ac_cv_have_elf_style_weakref" = xyes; then |
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| 45 | AC_DEFINE(HAVE_ELF_STYLE_WEAKREF, 1, [Define to 1 if target has a weakref that works like the ELF one.]) |
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| 46 | fi]) |
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| 47 | |
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