re PR target/49437 (interrupt return pop sometimes corrupts sp)

       PR target/49437
       * config/arm/arm.c (arm_output_epilogue): Properly handle epilogue
       when stack was realigned in interrupt handler prologue.

testsuite:

       PR target/49437
       * gcc.target/arm/handler-align.c: New test.
       * lib/target-supports.exp (check_effective_target_arm_cortex_m):
         New Function.

From-SVN: r177891

gcc/ChangeLog

+2011-08-19  Matthew Gretton-Dann  <matthew.gretton-dann@arm.com>
+
+	PR target/49437
+	* config/arm/arm.c (arm_output_epilogue): Properly handle epilogue
+	when stack was realigned in interrupt handler prologue.
+
 2011-08-18  Joseph Myers  <joseph@codesourcery.com>
 
 	* c-decl.c (shadow_tag_warned): Check for _Noreturn.

gcc/config/arm/arm.c

@@ -15230,6 +15230,7 @@ arm_output_epilogue (rtx sibling)
 		  && !crtl->calls_eh_return
 		  && bit_count(saved_regs_mask) * 4 == count
 		  && !IS_INTERRUPT (func_type)
+		  && !IS_STACKALIGN (func_type)
 		  && !crtl->tail_call_emit)
 		{
 		  unsigned long mask;

gcc/testsuite/ChangeLog

 2011-08-19  Joey Ye  <joey.ye@arm.com>
 
+	PR target/49437
+	* gcc.target/arm/handler-align.c: New test.
+	* lib/target-supports.exp (check_effective_target_arm_cortex_m):
+	New Function.
+
+2011-08-19  Joey Ye  <joey.ye@arm.com>
+
 	* gcc.c-torture/execute/20101011-1.c (DO_TEST): Skip on ARM.
 
 2011-08-19  Mikael Morin  <mikael.morin@sfr.fr>

gcc/testsuite/gcc.target/arm/handler-align.c

+/* Test epilogue of a realigned interrupt handler. */
+/* { dg-do run } */
+/* { dg-options "-mthumb -Os" } */
+/* { dg-skip-if "" { ! { arm_thumb1_ok || arm_thumb2_ok } } } */
+/* { dg-require-effective-target arm_cortex_m } */
+/* { dg-require-effective-target arm_eabi } */
+
+extern __attribute__((noreturn)) void abort(void);
+extern int snprintf(char *, int, const char *, ...);
+
+#define BUFF_LEN 256
+char buff[BUFF_LEN];
+
+char *get_buffer(void)
+{
+	return buff;
+}
+
+void __attribute__((interrupt)) foo(void)
+{
+        char *msg = get_buffer();
+        snprintf(msg, BUFF_LEN, "%d %p", 1, buff+BUFF_LEN);
+}
+
+volatile void * save_sp;
+int main()
+{
+	register volatile void * sp asm("sp");
+	/* Check stack pointer before/after calling the interrupt
+         * handler. Not equal means that handler doesn't restore
+         * stack correctly.  */
+	save_sp = sp;
+	foo();
+	/* Abort here instead of return non-zero. Due to wrong sp, lr value,
+	 * returning from main may not work.  */
+	if (save_sp != sp)
+	{
+		sp = save_sp;
+		abort();
+	}
+	return 0;
+}

gcc/testsuite/lib/target-supports.exp

@@ -2116,6 +2116,19 @@ proc check_effective_target_arm_thumb2 { } {
     } ""]
 }
 
+# Return 1 if this is an ARM cortex-M profile cpu
+
+proc check_effective_target_arm_cortex_m { } {
+    return [check_no_compiler_messages arm_cortex_m assembly {
+	#if !defined(__ARM_ARCH_7M__) \
+            && !defined (__ARM_ARCH_7EM__) \
+            && !defined (__ARM_ARCH_6M__)
+	#error FOO
+	#endif
+	int i;
+    } "-mthumb"]
+}
+
 # Return 1 if the target supports executing NEON instructions, 0
 # otherwise.  Cache the result.