merge from gcc

1 files changed, 52 insertions, 0 deletions

diff --git a/libiberty/aclocal.m4 b/libiberty/aclocal.m4
index c562835277..7b1b677645 100644
--- a/libiberty/aclocal.m4
+++ b/libiberty/aclocal.m4
@@ -134,3 +134,55 @@ define(AC_DEFINE_NOAUTOHEADER,
 [#define] $1 ifelse($#, 2, [$2], $#, 3, [$2], 1)
 EOF
 ])
+
+# We always want a C version of alloca() compiled into libiberty,
+# because native-compiler support for the real alloca is so !@#$%
+# unreliable that GCC has decided to use it only when being compiled
+# by GCC.  This is the part of AC_FUNC_ALLOCA that calculates the
+# information alloca.c needs.
+AC_DEFUN(libiberty_AC_FUNC_C_ALLOCA,
+[AC_CACHE_CHECK(whether alloca needs Cray hooks, ac_cv_os_cray,
+[AC_EGREP_CPP(webecray,
+[#if defined(CRAY) && ! defined(CRAY2)
+webecray
+#else
+wenotbecray
+#endif
+], ac_cv_os_cray=yes, ac_cv_os_cray=no)])
+if test $ac_cv_os_cray = yes; then
+  for ac_func in _getb67 GETB67 getb67; do
+    AC_CHECK_FUNC($ac_func, 
+      [AC_DEFINE_UNQUOTED(CRAY_STACKSEG_END, $ac_func, 
+  [Define to one of _getb67, GETB67, getb67 for Cray-2 and Cray-YMP
+   systems. This function is required for alloca.c support on those
+   systems.])  break])
+  done
+fi
+
+AC_CACHE_CHECK(stack direction for C alloca, ac_cv_c_stack_direction,
+[AC_TRY_RUN([find_stack_direction ()
+{
+  static char *addr = 0;
+  auto char dummy;
+  if (addr == 0)
+    {
+      addr = &dummy;
+      return find_stack_direction ();
+    }
+  else
+    return (&dummy > addr) ? 1 : -1;
+}
+main ()
+{
+  exit (find_stack_direction() < 0);
+}], 
+  ac_cv_c_stack_direction=1,
+  ac_cv_c_stack_direction=-1,
+  ac_cv_c_stack_direction=0)])
+AC_DEFINE_UNQUOTED(STACK_DIRECTION, $ac_cv_c_stack_direction,
+  [Define if you know the direction of stack growth for your system;
+   otherwise it will be automatically deduced at run-time.
+        STACK_DIRECTION > 0 => grows toward higher addresses
+        STACK_DIRECTION < 0 => grows toward lower addresses
+        STACK_DIRECTION = 0 => direction of growth unknown])
+])