gdb/arm: Don't rely on loop detection to stop unwinding

Setting SP of the next frame to the same address as the current frame
is an ugly way to stop the unwinding.  A cleaner way is to rely on
the frame_unwind_stop_reason function to return UNWIND_OUTERMOST.

Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@foss.st.com>

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index fa6b08e4a5459c723bcbee668cc6a848c301741b..b5facae8a5ea60112ed050d9f6aacc981e7ec818 100644 (file)
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -3356,7 +3356,6 @@ arm_m_exception_cache (frame_info_ptr this_frame)
      to the exception and if FPU is used (causing extended stack frame).  */
 
   CORE_ADDR lr = get_frame_register_unsigned (this_frame, ARM_LR_REGNUM);
-  CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
 
   /* ARMv7-M Architecture Reference "A2.3.1 Arm core registers"
      states that LR is set to 0xffffffff on reset.  ARMv8-M Architecture
@@ -3364,8 +3363,8 @@ arm_m_exception_cache (frame_info_ptr this_frame)
      reset if Main Extension is implemented, otherwise the value is unknown.  */
   if (lr == 0xffffffff)
     {
-      /* Terminate any further stack unwinding by referring to self.  */
-      arm_cache_set_active_sp_value (cache, tdep, sp);
+      /* Terminate any further stack unwinding.  */
+      arm_cache_set_active_sp_value (cache, tdep, 0);
       return cache;
     }
 
@@ -3387,8 +3386,8 @@ arm_m_exception_cache (frame_info_ptr this_frame)
        {
          warning (_("Non-secure to secure stack unwinding disabled."));
 
-         /* Terminate any further stack unwinding by referring to self.  */
-         arm_cache_set_active_sp_value (cache, tdep, sp);
+         /* Terminate any further stack unwinding.  */
+         arm_cache_set_active_sp_value (cache, tdep, 0);
          return cache;
        }
 
@@ -3452,8 +3451,8 @@ arm_m_exception_cache (frame_info_ptr this_frame)
            {
              warning (_("Non-secure to secure stack unwinding disabled."));
 
-             /* Terminate any further stack unwinding by referring to self.  */
-             arm_cache_set_active_sp_value (cache, tdep, sp);
+             /* Terminate any further stack unwinding.  */
+             arm_cache_set_active_sp_value (cache, tdep, 0);
              return cache;
            }