Per-inferior/Inferior-qualified thread IDs

This commit changes GDB to track thread numbers per-inferior.  Then,
if you're debugging multiple inferiors, GDB displays
"inferior-num.thread-num" instead of just "thread-num" whenever it
needs to display a thread:

 (gdb) info inferiors
   Num  Description       Executable
   1    process 6022     /home/pedro/gdb/tests/threads
 * 2    process 6037     /home/pedro/gdb/tests/threads
 (gdb) info threads
   Id   Target Id         Frame
   1.1  Thread 0x7ffff7fc2740 (LWP 6022) "threads" (running)
   1.2  Thread 0x7ffff77c0700 (LWP 6028) "threads" (running)
   1.3  Thread 0x7ffff7fc2740 (LWP 6032) "threads" (running)
   2.1  Thread 0x7ffff7fc1700 (LWP 6037) "threads" (running)
   2.2  Thread 0x7ffff77c0700 (LWP 6038) "threads" (running)
 * 2.3  Thread 0x7ffff7fc2740 (LWP 6039) "threads" (running)
 (gdb)
...
 (gdb) thread 1.1
 [Switching to thread 1.1 (Thread 0x7ffff7fc2740 (LWP 8155))]
 (gdb)
...

etc.

You can still use "thread NUM", in which case GDB infers you're
referring to thread NUM of the current inferior.

The $_thread convenience var and Python's InferiorThread.num attribute
are remapped to the new per-inferior thread number.  It's a backward
compatibility break, but since it only matters when debugging multiple
inferiors, I think it's worth doing.

Because MI thread IDs need to be a single integer, we keep giving
threads a global identifier, _in addition_ to the per-inferior number,
and make MI always refer to the global thread IDs.  IOW, nothing
changes from a MI frontend's perspective.

Similarly, since Python's Breakpoint.thread and Guile's
breakpoint-thread/set-breakpoint-thread breakpoint methods need to
work with integers, those are adjusted to work with global thread IDs
too.  Follow up patches will provide convenient means to access
threads' global IDs.

To avoid potencially confusing users (which also avoids updating much
of the testsuite), if there's only one inferior and its ID is "1",
IOW, the user hasn't done anything multi-process/inferior related,
then the "INF." part of thread IDs is not shown.  E.g,.:

 (gdb) info inferiors
   Num  Description       Executable
 * 1    process 15275     /home/pedro/gdb/tests/threads
 (gdb) info threads
   Id   Target Id         Frame
 * 1    Thread 0x7ffff7fc1740 (LWP 15275) "threads" main () at threads.c:40
 (gdb) add-inferior
 Added inferior 2
 (gdb) info threads
   Id   Target Id         Frame
 * 1.1  Thread 0x7ffff7fc1740 (LWP 15275) "threads" main () at threads.c:40
 (gdb)

No regressions on x86_64 Fedora 20.

gdb/ChangeLog:
2016-01-13  Pedro Alves  <palves@redhat.com>

	* NEWS: Mention that thread IDs are now per inferior and global
	thread IDs.
	* Makefile.in (SFILES): Add tid-parse.c.
	(COMMON_OBS): Add tid-parse.o.
	(HFILES_NO_SRCDIR): Add tid-parse.h.
	* ada-tasks.c: Adjust to use ptid_to_global_thread_id.
	* breakpoint.c (insert_breakpoint_locations)
	(remove_threaded_breakpoints, bpstat_check_breakpoint_conditions)
	(print_one_breakpoint_location, set_longjmp_breakpoint)
	(check_longjmp_breakpoint_for_call_dummy)
	(set_momentary_breakpoint): Adjust to use global IDs.
	(find_condition_and_thread, watch_command_1): Use parse_thread_id.
	(until_break_command, longjmp_bkpt_dtor)
	(breakpoint_re_set_thread, insert_single_step_breakpoint): Adjust
	to use global IDs.
	* dummy-frame.c (pop_dummy_frame_bpt): Adjust to use
	ptid_to_global_thread_id.
	* elfread.c (elf_gnu_ifunc_resolver_stop): Likewise.
	* gdbthread.h (struct thread_info): Rename field 'num' to
	'global_num.  Add new fields 'per_inf_num' and 'inf'.
	(thread_id_to_pid): Rename thread_id_to_pid to
	global_thread_id_to_ptid.
	(pid_to_thread_id): Rename to ...
	(ptid_to_global_thread_id): ... this.
	(valid_thread_id): Rename to ...
	(valid_global_thread_id): ... this.
	(find_thread_id): Rename to ...
	(find_thread_global_id): ... this.
	(ALL_THREADS, ALL_THREADS_BY_INFERIOR): Declare.
	(print_thread_info): Add comment.
	* tid-parse.h: New file.
	* tid-parse.c: New file.
	* infcmd.c (step_command_fsm_prepare)
	(step_command_fsm_should_stop): Adjust to use the global thread
	ID.
	(until_next_command, until_next_command)
	(finish_command_fsm_should_stop): Adjust to use the global thread
	ID.
	(attach_post_wait): Adjust to check the inferior number too.
	* inferior.h (struct inferior) <highest_thread_num>: New field.
	* infrun.c (handle_signal_stop)
	(insert_exception_resume_breakpoint)
	(insert_exception_resume_from_probe): Adjust to use the global
	thread ID.
	* record-btrace.c (record_btrace_open): Use global thread IDs.
	* remote.c (process_initial_stop_replies): Also consider the
	inferior number.
	* target.c (target_pre_inferior): Clear the inferior's highest
	thread num.
	* thread.c (clear_thread_inferior_resources): Adjust to use the
	global thread ID.
	(new_thread): New inferior parameter.  Adjust to use it.  Set both
	the thread's global ID and the thread's per-inferior ID.
	(add_thread_silent): Adjust.
	(find_thread_global_id): New.
	(find_thread_id): Make static.  Adjust to rename.
	(valid_thread_id): Rename to ...
	(valid_global_thread_id): ... this.
	(pid_to_thread_id): Rename to ...
	(ptid_to_global_thread_id): ... this.
	(thread_id_to_pid): Rename to ...
	(global_thread_id_to_ptid): ... this.  Adjust.
	(first_thread_of_process): Adjust.
	(do_captured_list_thread_ids): Adjust to use global thread IDs.
	(should_print_thread): New function.
	(print_thread_info): Rename to ...
	(print_thread_info_1): ... this, and add new show_global_ids
	parameter.  Handle it.  Iterate over inferiors.
	(print_thread_info): Reimplement as wrapper around
	print_thread_info_1.
	(show_inferior_qualified_tids): New function.
	(print_thread_id): Use it.
	(tp_array_compar): Compare inferior numbers too.
	(thread_apply_command): Use tid_range_parser.
	(do_captured_thread_select): Use parse_thread_id.
	(thread_id_make_value): Adjust.
	(_initialize_thread): Adjust "info threads" help string.
	* varobj.c (struct varobj_root): Update comment.
	(varobj_create): Adjust to use global thread IDs.
	(value_of_root_1): Adjust to use global_thread_id_to_ptid.
	* windows-tdep.c (display_tib): No longer accept an argument.
	* cli/cli-utils.c (get_number_trailer): Make extern.
	* cli/cli-utils.h (get_number_trailer): Declare.
	(get_number_const): Adjust documentation.
	* mi/mi-cmd-var.c (mi_cmd_var_update_iter): Adjust to use global
	thread IDs.
	* mi/mi-interp.c (mi_new_thread, mi_thread_exit)
	(mi_on_normal_stop, mi_output_running_pid, mi_on_resume):
	* mi/mi-main.c (mi_execute_command, mi_cmd_execute): Likewise.
	* guile/scm-breakpoint.c (gdbscm_set_breakpoint_thread_x):
	Likewise.
	* python/py-breakpoint.c (bppy_set_thread): Likewise.
	* python/py-finishbreakpoint.c (bpfinishpy_init): Likewise.
	* python/py-infthread.c (thpy_get_num): Add comment and return the
	per-inferior thread ID.
	(thread_object_getset): Update comment of "num".

gdb/testsuite/ChangeLog:
2016-01-07  Pedro Alves  <palves@redhat.com>

	* gdb.base/break.exp: Adjust to output changes.
	* gdb.base/hbreak2.exp: Likewise.
	* gdb.base/sepdebug.exp: Likewise.
	* gdb.base/watch_thread_num.exp: Likewise.
	* gdb.linespec/keywords.exp: Likewise.
	* gdb.multi/info-threads.exp: Likewise.
	* gdb.threads/thread-find.exp: Likewise.
	* gdb.multi/tids.c: New file.
	* gdb.multi/tids.exp: New file.

gdb/doc/ChangeLog:
2016-01-07  Pedro Alves  <palves@redhat.com>

	* gdb.texinfo (Threads): Document per-inferior thread IDs,
	qualified thread IDs, global thread IDs and thread ID lists.
	(Set Watchpoints, Thread-Specific Breakpoints): Adjust to refer to
	thread IDs.
	(Convenience Vars): Document the $_thread convenience variable.
	(Ada Tasks): Adjust to refer to thread IDs.
	(GDB/MI Async Records, GDB/MI Thread Commands, GDB/MI Ada Tasking
	Commands, GDB/MI Variable Objects): Update to mention global
	thread IDs.
	* guile.texi (Breakpoints In Guile)
	<breakpoint-thread/set-breakpoint-thread breakpoint>: Mention
	global thread IDs instead of thread IDs.
	* python.texi (Threads In Python): Adjust documentation of
	InferiorThread.num.
	(Breakpoint.thread): Mention global thread IDs instead of thread
	IDs.

1 files changed, 32 insertions, 35 deletions

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index b2a3c47..72da4ef 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -69,6 +69,7 @@
 #include "format.h"
 #include "location.h"
 #include "thread-fsm.h"
+#include "tid-parse.h"
 
 /* readline include files */
 #include "readline/readline.h"
@@ -3144,7 +3145,7 @@ insert_breakpoint_locations (void)
 	 the thread no longer exists.  ALL_BP_LOCATIONS bp_location
 	 has BL->OWNER always non-NULL.  */
       if (bl->owner->thread != -1
-	  && !valid_thread_id (bl->owner->thread))
+	  && !valid_global_thread_id (bl->owner->thread))
 	continue;
 
       switch_to_program_space_and_thread (bl->pspace);
@@ -3244,7 +3245,7 @@ remove_threaded_breakpoints (struct thread_info *tp, int silent)
 
   ALL_BREAKPOINTS_SAFE (b, b_tmp)
     {
-      if (b->thread == tp->num && user_breakpoint_p (b))
+      if (b->thread == tp->global_num && user_breakpoint_p (b))
 	{
 	  b->disposition = disp_del_at_next_stop;
 
@@ -5447,7 +5448,7 @@ bpstat_check_breakpoint_conditions (bpstat bs, ptid_t ptid)
   /* If this is a thread/task-specific breakpoint, don't waste cpu
      evaluating the condition if this isn't the specified
      thread/task.  */
-  if ((b->thread != -1 && b->thread != pid_to_thread_id (ptid))
+  if ((b->thread != -1 && b->thread != ptid_to_global_thread_id (ptid))
       || (b->task != 0 && b->task != ada_get_task_number (ptid)))
 
     {
@@ -6514,11 +6515,16 @@ print_one_breakpoint_location (struct breakpoint *b,
 
   if (!part_of_multiple && b->thread != -1)
     {
-      struct thread_info *thr = find_thread_id (b->thread);
-
       /* FIXME should make an annotation for this.  */
       ui_out_text (uiout, "\tstop only in thread ");
-      ui_out_field_string (uiout, "thread", print_thread_id (thr));
+      if (ui_out_is_mi_like_p (uiout))
+	ui_out_field_int (uiout, "thread", b->thread);
+      else
+	{
+	  struct thread_info *thr = find_thread_global_id (b->thread);
+
+	  ui_out_field_string (uiout, "thread", print_thread_id (thr));
+	}
       ui_out_text (uiout, "\n");
     }
   
@@ -7574,7 +7580,7 @@ void
 set_longjmp_breakpoint (struct thread_info *tp, struct frame_id frame)
 {
   struct breakpoint *b, *b_tmp;
-  int thread = tp->num;
+  int thread = tp->global_num;
 
   /* To avoid having to rescan all objfile symbols at every step,
      we maintain a list of continually-inserted but always disabled
@@ -7643,7 +7649,7 @@ set_longjmp_breakpoint_for_call_dummy (void)
 	new_b = momentary_breakpoint_from_master (b, bp_longjmp_call_dummy,
 						  &momentary_breakpoint_ops,
 						  1);
-	new_b->thread = pid_to_thread_id (inferior_ptid);
+	new_b->thread = ptid_to_global_thread_id (inferior_ptid);
 
 	/* Link NEW_B into the chain of RETVAL breakpoints.  */
 
@@ -7673,7 +7679,7 @@ check_longjmp_breakpoint_for_call_dummy (struct thread_info *tp)
   struct breakpoint *b, *b_tmp;
 
   ALL_BREAKPOINTS_SAFE (b, b_tmp)
-    if (b->type == bp_longjmp_call_dummy && b->thread == tp->num)
+    if (b->type == bp_longjmp_call_dummy && b->thread == tp->global_num)
       {
 	struct breakpoint *dummy_b = b->related_breakpoint;
 
@@ -8893,7 +8899,7 @@ set_momentary_breakpoint (struct gdbarch *gdbarch, struct symtab_and_line sal,
      momentary breakpoints to be active in only a single thread of
      control.  */
   if (in_thread_list (inferior_ptid))
-    b->thread = pid_to_thread_id (inferior_ptid);
+    b->thread = ptid_to_global_thread_id (inferior_ptid);
 
   update_global_location_list_nothrow (UGLL_MAY_INSERT);
 
@@ -9567,14 +9573,6 @@ check_fast_tracepoint_sals (struct gdbarch *gdbarch,
     }
 }
 
-/* Issue an invalid thread ID error.  */
-
-static void ATTRIBUTE_NORETURN
-invalid_thread_id_error (int id)
-{
-  error (_("Unknown thread %d."), id);
-}
-
 /* Given TOK, a string specification of condition and thread, as
    accepted by the 'break' command, extract the condition
    string and thread number and set *COND_STRING and *THREAD.
@@ -9623,14 +9621,14 @@ find_condition_and_thread (const char *tok, CORE_ADDR pc,
 	}
       else if (toklen >= 1 && strncmp (tok, "thread", toklen) == 0)
 	{
-	  char *tmptok;
+	  const char *tmptok;
+	  struct thread_info *thr;
 
 	  tok = end_tok + 1;
-	  *thread = strtol (tok, &tmptok, 0);
+	  thr = parse_thread_id (tok, &tmptok);
 	  if (tok == tmptok)
 	    error (_("Junk after thread keyword."));
-	  if (!valid_thread_id (*thread))
-	    invalid_thread_id_error (*thread);
+	  *thread = thr->global_num;
 	  tok = tmptok;
 	}
       else if (toklen >= 1 && strncmp (tok, "task", toklen) == 0)
@@ -11135,25 +11133,23 @@ watch_command_1 (const char *arg, int accessflag, int from_tty,
 
 	  if (toklen == 6 && startswith (tok, "thread"))
 	    {
+	      struct thread_info *thr;
 	      /* At this point we've found a "thread" token, which means
 		 the user is trying to set a watchpoint that triggers
 		 only in a specific thread.  */
-	      char *endp;
+	      const char *endp;
 
 	      if (thread != -1)
 		error(_("You can specify only one thread."));
 
 	      /* Extract the thread ID from the next token.  */
-	      thread = strtol (value_start, &endp, 0);
+	      thr = parse_thread_id (value_start, &endp);
 
-	      /* Check if the user provided a valid numeric value for the
-		 thread ID.  */
+	      /* Check if the user provided a valid thread ID.  */
 	      if (*endp != ' ' && *endp != '\t' && *endp != '\0')
-		error (_("Invalid thread ID specification %s."), value_start);
+		invalid_thread_id_error (value_start);
 
-	      /* Check if the thread actually exists.  */
-	      if (!valid_thread_id (thread))
-		invalid_thread_id_error (thread);
+	      thread = thr->global_num;
 	    }
 	  else if (toklen == 4 && startswith (tok, "mask"))
 	    {
@@ -11694,7 +11690,7 @@ until_break_command (char *arg, int from_tty, int anywhere)
   resolve_sal_pc (&sal);
 
   tp = inferior_thread ();
-  thread = tp->num;
+  thread = tp->global_num;
 
   old_chain = make_cleanup (null_cleanup, NULL);
 
@@ -11744,7 +11740,8 @@ until_break_command (char *arg, int from_tty, int anywhere)
 						    stack_frame_id, bp_until);
   make_cleanup_delete_breakpoint (location_breakpoint);
 
-  sm = new_until_break_fsm (tp->num, location_breakpoint, caller_breakpoint);
+  sm = new_until_break_fsm (tp->global_num,
+			    location_breakpoint, caller_breakpoint);
   tp->thread_fsm = &sm->thread_fsm;
 
   discard_cleanups (old_chain);
@@ -13366,7 +13363,7 @@ momentary_bkpt_print_mention (struct breakpoint *b)
 static void
 longjmp_bkpt_dtor (struct breakpoint *self)
 {
-  struct thread_info *tp = find_thread_id (self->thread);
+  struct thread_info *tp = find_thread_global_id (self->thread);
 
   if (tp)
     tp->initiating_frame = null_frame_id;
@@ -14547,7 +14544,7 @@ breakpoint_re_set_thread (struct breakpoint *b)
   if (b->thread != -1)
     {
       if (in_thread_list (inferior_ptid))
-	b->thread = pid_to_thread_id (inferior_ptid);
+	b->thread = ptid_to_global_thread_id (inferior_ptid);
 
       /* We're being called after following a fork.  The new fork is
 	 selected as current, and unless this was a vfork will have a
@@ -15058,7 +15055,7 @@ insert_single_step_breakpoint (struct gdbarch *gdbarch,
   if (tp->control.single_step_breakpoints == NULL)
     {
       tp->control.single_step_breakpoints
-	= new_single_step_breakpoint (tp->num, gdbarch);
+	= new_single_step_breakpoint (tp->global_num, gdbarch);
     }
 
   sal = find_pc_line (pc, 0);