[RFC 2/4] [gdb] Introduce maint set prefer-software-single-stepping on/off

[Tom de Vries <tdevries@suse.de>]

Add a maintenance command that enables using software single-stepping on
targets that support this:
...
(gdb) maint set prefer-software-single-stepping on
...

By default, prefer-software-single-stepping is off, and behaviour is
unchanged.

Also, there are no users yet, the following patch will add one for amd64.

This is an RFC for the moment, so no docs yet.

Tested on x86_64-linux.
---
 gdb/breakpoint.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 60e795e1849..3d90e2a2159 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -13945,6 +13945,9 @@ insert_single_step_breakpoint (struct gdbarch *gdbarch,
   update_global_location_list (UGLL_INSERT);
 }
 
+extern bool prefer_software_single_stepping;
+bool prefer_software_single_stepping;
+
 bool
 software_single_step_p (struct gdbarch *gdbarch)
 {
@@ -15168,6 +15171,16 @@ When on, breakpoint location specific debugging is enabled."),
 			   show_debug_breakpoint,
 			   &setdebuglist, &showdebuglist);
 
+  add_setshow_boolean_cmd ("prefer-software-single-stepping", class_maintenance,
+			   &prefer_software_single_stepping, _("\
+Set whether software single-stepping is preferred."), _("\
+Show whether software single-stepping is preferred."), _("\
+When on, if both are available, software single-stepping is preferred over hardware single-stepping."),
+			   NULL,
+			   NULL,
+			   &maintenance_set_cmdlist,
+			   &maintenance_show_cmdlist);
+
   add_setshow_enum_cmd ("condition-evaluation", class_breakpoint,
 			condition_evaluation_enums,
 			&condition_evaluation_mode_1, _("\
-- 
2.35.3