[Patch 3/7, Arm, GCC] Add testsuite library support for PACBTI target.

[Tejas Belagod via Gcc-patches]

Hi,

Add targeting-checking entities for PACBTI in testsuite
framework.

Tested on arm-none-eabi. OK for trunk?

2021-10-04  Tejas Belagod  <tbela...@arm.com>

gcc/ChangeLog:

        * testsuite/lib/target-supports.exp
        (check_effective_target_arm_pacbti_hw): New.

diff --git a/gcc/testsuite/lib/target-supports.exp 
b/gcc/testsuite/lib/target-supports.exp
index 
9ebca7ac007363d2a35158bb80092118f629b97b..323541c2da527e3da5dce4d85cadcb2068d9bb5c
 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -5064,6 +5064,22 @@ proc check_effective_target_arm_cmse_clear_ok {} {
     } "-mcmse"];
 }
 
+# Return 1 if the target supports executing PACBTI instructions, 0
+# otherwise.
+
+proc check_effective_target_arm_pacbti_hw {} {
+    return [check_runtime arm_pacbti_hw_available {
+       __attribute__ ((naked)) int
+       main (void)
+       {
+         asm ("pac r12, lr, sp");
+         asm ("mov r0, #0");
+         asm ("autg r12, lr, sp");
+         asm ("bx lr");
+       }
+    } ""]
+}
+
 # Return 1 if this compilation turns on string_ops_prefer_neon on.
 
 proc check_effective_target_arm_tune_string_ops_prefer_neon { } {