gdbserver/linux-low: turn 'supports_hardware_single_step' into a method

All the linux low targets except arm define the
'supports_hardware_single_step' op to return true.  Hence, we override
the method to return true in linux_process_target, and remove the
definitions in all the linux low targets but arm.

gdbserver/ChangeLog:
2020-04-02  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	Remove the 'supports_hardware_single_step' linux target op and
	override the process_stratum_target's op definition in
	linux_process_target to return true.

	* linux-low.h (struct linux_target_ops): Remove the op.
	(class linux_process_target) <finish_step_over>
	<maybe_hw_step>: Declare.
	* linux-low.cc (can_hardware_single_step): Remove.
	(maybe_hw_step): Turn into...
	(linux_process_target::maybe_hw_step): ...this.
	(finish_step_over): Turn into...
	(linux_process_target::finish_step_over): ...this.
	(linux_process_target::supports_hardware_single_step): Update
	to return true.

	Update the callers below.

	(linux_process_target::single_step)
	(linux_process_target::resume_one_lwp_throw)

	* linux-arm-low.cc (class arm_target)
	<supports_hardware_single_step>: Declare.
	(arm_supports_hardware_single_step): Turn into...
	(arm_target::supports_hardware_single_step): ...this.
	(the_low_target): Remove the op field.
	* linux-x86-low.cc (x86_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-aarch64-low.cc (aarch64_supports_hardware_single_step):
	Remove.
	(the_low_target): Remove the op field.
	* linux-bfin-low.cc (bfin_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-crisv32-low.cc (cris_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-m32r-low.cc (m32r_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-m68k-low.cc (m68k_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-ppc-low.cc (ppc_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-s390-low.cc (s390_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-sh-low.cc (sh_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-tic6x-low.cc (tic6x_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-tile-low.cc (tile_supports_hardware_single_step): Remove.
	(the_low_target): Remove the op field.
	* linux-xtensa-low.cc (xtensa_supports_hardware_single_step):
	Remove.
	(the_low_target): Remove the op field.

1 files changed, 14 insertions, 32 deletions

diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc
index 7ec01f4..5661543 100644
--- a/gdbserver/linux-low.cc
+++ b/gdbserver/linux-low.cc
@@ -270,7 +270,6 @@ static int stabilizing_threads;
 static void unsuspend_all_lwps (struct lwp_info *except);
 static void mark_lwp_dead (struct lwp_info *lwp, int wstat);
 static int lwp_is_marked_dead (struct lwp_info *lwp);
-static int finish_step_over (struct lwp_info *lwp);
 static int kill_lwp (unsigned long lwpid, int signo);
 static void enqueue_pending_signal (struct lwp_info *lwp, int signal, siginfo_t *info);
 static int linux_low_ptrace_options (int attached);
@@ -280,17 +279,6 @@ static int check_ptrace_stopped_lwp_gone (struct lwp_info *lp);
    being stepped.  */
 ptid_t step_over_bkpt;
 
-/* True if the low target can hardware single-step.  */
-
-static int
-can_hardware_single_step (void)
-{
-  if (the_low_target.supports_hardware_single_step != NULL)
-    return the_low_target.supports_hardware_single_step ();
-  else
-    return 0;
-}
-
 bool
 linux_process_target::low_supports_breakpoints ()
 {
@@ -2503,19 +2491,17 @@ linux_process_target::filter_event (int lwpid, int wstat)
   return child;
 }
 
-/* Return true if THREAD is doing hardware single step.  */
-
-static int
-maybe_hw_step (struct thread_info *thread)
+bool
+linux_process_target::maybe_hw_step (thread_info *thread)
 {
-  if (can_hardware_single_step ())
-    return 1;
+  if (supports_hardware_single_step ())
+    return true;
   else
     {
       /* GDBserver must insert single-step breakpoint for software
 	 single step.  */
       gdb_assert (has_single_step_breakpoints (thread));
-      return 0;
+      return false;
     }
 }
 
@@ -4107,7 +4093,7 @@ linux_process_target::single_step (lwp_info* lwp)
 {
   int step = 0;
 
-  if (can_hardware_single_step ())
+  if (supports_hardware_single_step ())
     {
       step = 1;
     }
@@ -4218,7 +4204,7 @@ linux_process_target::resume_one_lwp_throw (lwp_info *lwp, int step,
 	debug_printf ("  pending reinsert at 0x%s\n",
 		      paddress (lwp->bp_reinsert));
 
-      if (can_hardware_single_step ())
+      if (supports_hardware_single_step ())
 	{
 	  if (fast_tp_collecting == fast_tpoint_collect_result::not_collecting)
 	    {
@@ -4247,7 +4233,7 @@ linux_process_target::resume_one_lwp_throw (lwp_info *lwp, int step,
 		      " single-stepping\n",
 		      lwpid_of (thread));
 
-      if (can_hardware_single_step ())
+      if (supports_hardware_single_step ())
 	step = 1;
       else
 	{
@@ -4700,12 +4686,8 @@ linux_process_target::start_step_over (lwp_info *lwp)
   step_over_bkpt = thread->id;
 }
 
-/* Finish a step-over.  Reinsert the breakpoint we had uninserted in
-   start_step_over, if still there, and delete any single-step
-   breakpoints we've set, on non hardware single-step targets.  */
-
-static int
-finish_step_over (struct lwp_info *lwp)
+bool
+linux_process_target::finish_step_over (lwp_info *lwp)
 {
   if (lwp->bp_reinsert != 0)
     {
@@ -4728,7 +4710,7 @@ finish_step_over (struct lwp_info *lwp)
 	 and later not being able to explain it, because we were
 	 stepping over a breakpoint, and we hold all threads but
 	 LWP stopped while doing that.  */
-      if (!can_hardware_single_step ())
+      if (!supports_hardware_single_step ())
 	{
 	  gdb_assert (has_single_step_breakpoints (current_thread));
 	  delete_single_step_breakpoints (current_thread);
@@ -4736,10 +4718,10 @@ finish_step_over (struct lwp_info *lwp)
 
       step_over_bkpt = null_ptid;
       current_thread = saved_thread;
-      return 1;
+      return true;
     }
   else
-    return 0;
+    return false;
 }
 
 void
@@ -5899,7 +5881,7 @@ linux_process_target::supports_stopped_by_hw_breakpoint ()
 bool
 linux_process_target::supports_hardware_single_step ()
 {
-  return can_hardware_single_step ();
+  return true;
 }
 
 bool