[pushed] Darwin: Fixes for darwin_libc_has_function.

[pushed] Darwin: Fixes for darwin_libc_has_function.

[Iain Sandoe]

Hi,

Firstly, the checks for availability need not be run for any
currently supported Darwin version (or for any version of
Darwin on x86).  In fact, the only test that is needed that
differs from the default is for the availability of sincos.
Test that and then fall back to the default implementation.

Secondly, the function appears to be called from the Jit library
before the value of darwin_macosx_version_min has been set up -
at present we work around this by guarding the checks on having
a non-null pointer for darwin_macosx_version_min.

tested on powerpc, i686, x86_64-darwin (and x86-64-linux),
pushed to master, thanks
Iain

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>

gcc/ChangeLog:

	* config/darwin.c (darwin_libc_has_function): Do not run
	the checks for x86 or modern Darwin.  Make sure that there
	is a value set for darwin_macosx_version_min before testing.
---
 gcc/config/darwin.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/gcc/config/darwin.c b/gcc/config/darwin.c
index 667fda79a60..781742fe46f 100644
--- a/gcc/config/darwin.c
+++ b/gcc/config/darwin.c
@@ -42,6 +42,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "explow.h"
 #include "expr.h"
 #include "langhooks.h"
+#include "targhooks.h"
 #include "toplev.h"
 #include "lto-section-names.h"
 #include "intl.h"
@@ -3661,19 +3662,22 @@ darwin_rename_builtins (void)
     }
 }
 
+/* Implementation for the TARGET_LIBC_HAS_FUNCTION hook.  */
+
 bool
 darwin_libc_has_function (enum function_class fn_class,
 			  tree type ATTRIBUTE_UNUSED)
 {
-  if (fn_class == function_sincos)
+  if (fn_class == function_sincos && darwin_macosx_version_min)
     return (strverscmp (darwin_macosx_version_min, "10.9") >= 0);
-
+#if DARWIN_PPC && SUPPORT_DARWIN_LEGACY
   if (fn_class == function_c99_math_complex
       || fn_class == function_c99_misc)
     return (TARGET_64BIT
-	    || strverscmp (darwin_macosx_version_min, "10.3") >= 0);
-
-  return true;
+	    || (darwin_macosx_version_min &&
+		strverscmp (darwin_macosx_version_min, "10.3") >= 0));
+#endif
+  return default_libc_has_function (fn_class, type);
 }
 
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