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Index: b/configure.ac
===================================================================
--- a/configure.ac
+++ b/configure.ac
@@ -112,6 +112,22 @@
if test "x$grub_cv_cc_no_stack_protector" = xyes; then
STAGE2_CFLAGS="$STAGE2_CFLAGS -fno-stack-protector"
fi
+ # GCC >= 3.3 supports -fno-reorder-functions; this defends us against
+ # unlikely-to-be-executed functions being linked before _start with GCC
+ # >= 4.6.
+ AC_CACHE_CHECK([whether gcc has -fno-reorder-functions],
+ no_reorder_functions_flag, [
+ saved_CFLAGS=$CFLAGS
+ CFLAGS="-fno-reorder-functions"
+ AC_TRY_COMPILE(,
+ ,
+ no_reorder_functions_flag=yes,
+ no_reorder_functions_flag=no)
+ CFLAGS=$saved_CFLAGS
+ ])
+ if test "x$no_reorder_functions_flag" = xyes; then
+ STAGE2_CFLAGS="$STAGE2_CFLAGS -fno-reorder-functions"
+ fi
fi
fi
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