[PATCH, ARM] Add test for ARMv7-M interrupt function dynamic stack realignment

[Julian Brown <julian at codesourcery dot com>]

Hi,

GCC has had a feature for many years to realign the stack for
interrupt-handler functions (marked with "__attribute__((interrupt))")
on Cortex-M-series devices (IIRC, this was a workaround for a hardware
issue, or perhaps some unforeseen circumstance when the stack could
become misaligned in user code):

http://gcc.gnu.org/ml/gcc-patches/2006-03/msg00038.html

The test case from the above patch unfortunately got mislaid at some
point when branches were merged. It still passes on current mainline
(using "-mthumb -march=armv7-m" when running tests).

I will apply this one as obvious.

Thanks,

Julian

ChangeLog

    Paul Brook  <paul@codesourcery.com>

    gcc/testsuite/
    * g++.dg/other/armv7m-1.c: New test.

Index: gcc/testsuite/g++.dg/other/armv7m-1.C
===================================================================
--- gcc/testsuite/g++.dg/other/armv7m-1.C	(revision 0)
+++ gcc/testsuite/g++.dg/other/armv7m-1.C	(revision 0)
@@ -0,0 +1,69 @@
+/* { dg-do run { target arm*-*-* } } */
+/* Test Armv7m interrupt routines.  */
+#include <stdlib.h>
+
+#ifdef __ARM_ARCH_7M__
+void __attribute__((interrupt))
+foo(void)
+{
+  long long n;
+  long p;
+  asm volatile ("" : "=r" (p) : "0" (&n));
+  if (p & 4)
+    abort ();
+  return;
+}
+
+void __attribute__((interrupt))
+bar(void)
+{
+  throw 42;
+}
+
+int main()
+{
+  int a;
+  int before;
+  int after;
+  volatile register int sp asm("sp");
+
+  asm volatile ("mov %0, sp\n"
+		"blx %2\n"
+		"mov %1, sp\n"
+		: "=&r" (before), "=r" (after) : "r" (foo)
+		: "memory", "cc", "r0", "r1", "r2", "r3", "ip", "lr");
+  if (before != after)
+    abort();
+  asm volatile ("mov %0, sp\n"
+		"sub sp, sp, #4\n"
+		"blx %2\n"
+		"add sp, sp, #4\n"
+		"mov %1, sp\n"
+		: "=&r" (before), "=r" (after) : "r" (foo)
+		: "memory", "cc", "r0", "r1", "r2", "r3", "ip", "lr");
+  if (before != after)
+    abort();
+  before = sp;
+  try
+    {
+      bar();
+    }
+  catch (int i)
+    {
+      if (i != 42)
+	abort();
+    }
+  catch (...)
+    {
+      abort();
+    }
+  if (before != sp)
+    abort();
+  exit(0);
+}
+#else
+int main()
+{
+  exit (0);
+}
+#endif