Add test for setjmp / longjmp and floating-point state

["Joseph S. Myers" <joseph at codesourcery dot com>]

A while back I noticed that the ARM and MIPS implementations of setjmp
/ longjmp wrongly saved and restored floating-point exceptions and
rounding modes, contrary to ISO C (bugs 14908 and 14909).  This patch
adds an architecture-independent test to detect this bug.  Tested
x86_64 and x86 that the new test passes, and on ARM that it properly
detects the bug and fails there.

2013-05-14  Joseph Myers  <joseph@codesourcery.com>

	* setjmp/tst-setjmp-fp.c: New file.
	* setjmp/Makefile (tests): Add tst-setjmp-fp.
	(link-libm): New variable.
	($(objpfx)tst-setjmp-fp): Depend on $(link-libm).

diff --git a/setjmp/Makefile b/setjmp/Makefile
index 2c2ead2..6124333 100644
--- a/setjmp/Makefile
+++ b/setjmp/Makefile
@@ -25,7 +25,14 @@ headers	:= setjmp.h bits/setjmp.h bits/setjmp2.h
 routines	:= setjmp sigjmp bsd-setjmp bsd-_setjmp \
 		   longjmp __longjmp jmp-unwind
 
-tests		:= tst-setjmp jmpbug bug269-setjmp
+tests		:= tst-setjmp jmpbug bug269-setjmp tst-setjmp-fp
 
 
 include ../Rules
+
+ifeq ($(build-shared),yes)
+link-libm = $(common-objpfx)math/libm.so
+else
+link-libm = $(common-objpfx)math/libm.a
+endif
+$(objpfx)tst-setjmp-fp: $(link-libm)
diff --git a/setjmp/tst-setjmp-fp.c b/setjmp/tst-setjmp-fp.c
new file mode 100644
index 0000000..dc2b4b0
--- /dev/null
+++ b/setjmp/tst-setjmp-fp.c
@@ -0,0 +1,105 @@
+/* Test that setjmp/longjmp do not save and restore floating-point
+   exceptions and rounding modes.
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+#include <setjmp.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static jmp_buf env;
+static int result = 0;
+
+#if defined FE_TONEAREST && defined FE_TOWARDZERO
+static int expected_rounding_mode = FE_TONEAREST;
+
+static void
+change_rounding_mode (void)
+{
+  if (fesetround (FE_TOWARDZERO) == 0)
+    expected_rounding_mode = FE_TOWARDZERO;
+  else
+    puts ("fesetround (FE_TOWARDZERO) failed, continuing test");
+  longjmp (env, 1);
+}
+#endif
+
+#ifdef FE_INVALID
+static int expected_exceptions = 0;
+
+static void
+raise_exception (void)
+{
+  if (feraiseexcept (FE_INVALID) == 0)
+    expected_exceptions = FE_INVALID;
+  else
+    puts ("feraiseexcept (FE_INVALID) failed, continuing test");
+  longjmp (env, 1);
+}
+#endif
+
+static int
+do_test (void)
+{
+#if defined FE_TONEAREST && defined FE_TOWARDZERO
+  if (fesetround (FE_TONEAREST) == 0)
+    {
+      if (setjmp (env) == 0)
+	change_rounding_mode ();
+      else
+	{
+	  if (fegetround () == expected_rounding_mode)
+	    puts ("PASS: longjmp preserved rounding mode");
+	  else
+	    {
+	      puts ("FAIL: longjmp changed rounding mode");
+	      result = 1;
+	    }
+	}
+    }
+  else
+    puts ("fesetround (FE_TONEAREST) failed, not testing rounding modes");
+#else
+  puts ("rounding mode test not supported");
+#endif
+#ifdef FE_INVALID
+  if (feclearexcept (FE_ALL_EXCEPT) == 0)
+    {
+      if (setjmp (env) == 0)
+	raise_exception ();
+      else
+	{
+	  if (fetestexcept (FE_INVALID) == expected_exceptions)
+	    puts ("PASS: longjmp preserved exceptions");
+	  else
+	    {
+	      puts ("FAIL: longjmp changed exceptions");
+	      result = 1;
+	    }
+	}
+    }
+  else
+    puts ("feclearexcept (FE_ALL_EXCEPT) failed, not testing exceptions");
+#else
+  puts ("exception test not supported");
+#endif
+  return result;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"

-- 
Joseph S. Myers
joseph@codesourcery.com