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.

3 files changed, 353 insertions, 1 deletions

diff --git a/gdb/testsuite/gdb.multi/info-threads.exp b/gdb/testsuite/gdb.multi/info-threads.exp
index 7ae60d7..f8d9c6d 100644
--- a/gdb/testsuite/gdb.multi/info-threads.exp
+++ b/gdb/testsuite/gdb.multi/info-threads.exp
@@ -36,4 +36,4 @@ gdb_test "inferior 2" "Switching to inferior 2.*" "switch to inferior 2"
 
 # "info threads" while inferior 1 has execution and inferior 2 is not
 # running yet should show inferior 1's thread, and give no error.
-gdb_test "info threads" "1    .* main .* at .*$srcfile:.*No selected thread.*"
+gdb_test "info threads" "1\.1 .* main .* at .*$srcfile:.*No selected thread.*"
diff --git a/gdb/testsuite/gdb.multi/tids.c b/gdb/testsuite/gdb.multi/tids.c
new file mode 100644
index 0000000..8a53d43
--- /dev/null
+++ b/gdb/testsuite/gdb.multi/tids.c
@@ -0,0 +1,56 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2015-2016 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <unistd.h>
+#include <pthread.h>
+
+pthread_t child_thread[2];
+
+void *
+thread_function2 (void *arg)
+{
+  while (1)
+    sleep (1);
+
+  return NULL;
+}
+
+void *
+thread_function1 (void *arg)
+{
+  pthread_create (&child_thread[1], NULL, thread_function2, NULL);
+
+  while (1)
+    sleep (1);
+
+  return NULL;
+}
+
+int
+main (void)
+{
+  int i;
+
+  alarm (300);
+
+  pthread_create (&child_thread[0], NULL, thread_function1, NULL);
+
+  for (i = 0; i < 2; i++)
+    pthread_join (child_thread[i], NULL);
+
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.multi/tids.exp b/gdb/testsuite/gdb.multi/tids.exp
new file mode 100644
index 0000000..70a1d81
--- /dev/null
+++ b/gdb/testsuite/gdb.multi/tids.exp
@@ -0,0 +1,296 @@
+# Copyright 2015-2016 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Test thread ID parsing and display.
+
+load_lib gdb-python.exp
+
+standard_testfile
+
+# Multiple inferiors are needed, therefore both native and extended
+# gdbserver modes are supported.  Only non-extended gdbserver is not
+# supported.
+if [target_info exists use_gdb_stub] {
+    untested ${testfile}.exp
+    return
+}
+
+if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} {pthreads debug}] } {
+    return -1
+}
+
+clean_restart ${testfile}
+
+if { ![runto_main] } then {
+    return -1
+}
+
+# Issue "thread apply TID_LIST p 1234" and expect EXP_TID_LIST (a list
+# of thread ids) to be displayed.
+proc thread_apply {tid_list exp_tid_list {message ""}} {
+    global decimal
+    set any "\[^\r\n\]*"
+    set expected [string_to_regexp $exp_tid_list]
+
+    set r ""
+    foreach tid $expected {
+	append r "\[\r\n\]+"
+	append r "Thread $tid $any:\r\n"
+	append r "\\$$decimal = 1234"
+    }
+
+    set cmd "thread apply $tid_list"
+    if {$message == ""} {
+	set message $cmd
+    }
+    gdb_test "$cmd p 1234" $r $message
+}
+
+# Issue "info threads TID_LIST" and expect EXP_TID_LIST (a list of
+# thread ids) to be displayed.
+proc info_threads {tid_list exp_tid_list {message ""}} {
+    set any "\[^\r\n\]*"
+    set expected [string_to_regexp $exp_tid_list]
+    set r [join $expected " ${any}\r\n${any} "]
+    set r "${any} $r ${any}"
+    set cmd "info threads $tid_list"
+    if {$message == ""} {
+	set message $cmd
+    }
+    gdb_test $cmd $r $message
+}
+
+# Issue "info threads TID_LIST" and expect INFO_THR output.  Then
+# issue "thread apply TID_LIST" and expect THR_APPLY output.  If
+# THR_APPLY is omitted, INFO_THR is expected instead.
+proc thr_apply_info_thr {tid_list info_thr {thr_apply ""}} {
+    if {$thr_apply == ""} {
+	set thr_apply $info_thr
+    }
+
+    info_threads $tid_list $info_thr
+    thread_apply $tid_list $thr_apply
+}
+
+# Issue both "info threads TID_LIST" and "thread apply TID_LIST" and
+# expect both commands to error out with EXP_ERROR.
+proc thr_apply_info_thr_error {tid_list exp_error}  {
+    gdb_test "info threads $tid_list" \
+	$exp_error
+
+    gdb_test "thread apply $tid_list p 1234" \
+	$exp_error \
+	"thread apply $tid_list"
+}
+
+# Issue both "info threads TID_LIST" and "thread apply TID_LIST" and
+# expect the command to error out with "Invalid thread ID: $EXPECTED".
+# EXPECTED is a literal string, not a regexp.
+proc thr_apply_info_thr_invalid {tid_list expected} {
+    set expected [string_to_regexp $expected]
+    gdb_test "info threads $tid_list" \
+	"Invalid thread ID: $expected"
+
+    gdb_test "thread apply $tid_list p 1234" \
+	"Invalid thread ID: $expected p 1234" \
+	"thread apply $tid_list"
+}
+
+# "info threads" while there's only inferior 1 should show
+# single-number thread IDs.
+with_test_prefix "single inferior" {
+    info_threads "" "1"
+
+    gdb_test "thread" "Current thread is 1 .*"
+}
+
+# "info threads" while there are multiple inferiors should show
+# qualified thread IDs.
+with_test_prefix "two inferiors" {
+    # Add another inferior.
+    gdb_test "add-inferior" "Added inferior 2.*" "add empty inferior 2"
+
+    # Now that we've added another inferior, thread IDs now show the
+    # inferior number.
+    info_threads "" "1.1"
+
+    gdb_test "thread" "Current thread is 1\.1 .*"
+
+    gdb_test "inferior 2" "Switching to inferior 2 .*" "switch to inferior 2"
+    gdb_test "file ${binfile}" ".*" "load file in inferior 2"
+
+    runto_main
+
+    # Now that we've added another inferior, thread IDs now show the
+    # inferior number.
+    info_threads "" "1.1 2.1" \
+	"info threads show inferior numbers"
+
+    gdb_test "thread" "Current thread is 2\.1 .*" \
+	"switch to thread using extended thread ID"
+
+    gdb_breakpoint "thread_function1"
+
+    gdb_continue_to_breakpoint "once"
+    gdb_test "inferior 1" "Switching to inferior 1 .*"
+    gdb_continue_to_breakpoint "twice"
+
+    info_threads "" "1.1 1.2 2.1 2.2" \
+	"info threads again"
+
+    # Confirm the convenience variable show the expected number.
+    gdb_test "p \$_thread == 2" " = 1"
+
+    # Without an explicit inferior component, GDB defaults to the
+    # current inferior.  Make sure we don't refer to a thread by
+    # global ID by mistake.
+    gdb_test "thread 4" "Unknown thread 1.4\\."
+
+    # Test thread ID list parsing.  Test qualified and unqualified
+    # IDs; qualified and unqualified ranges; invalid IDs and invalid
+    # ranges.
+
+    # First spawn a couple more threads so ranges includes more than
+    # two threads.
+    with_test_prefix "more threads" {
+	gdb_breakpoint "thread_function2"
+
+	gdb_test "inferior 2" "Switching to inferior 2 .*"
+	gdb_continue_to_breakpoint "once"
+
+	gdb_test "inferior 1" "Switching to inferior 1 .*"
+	gdb_continue_to_breakpoint "twice"
+    }
+
+    thr_apply_info_thr "1 2 3" \
+	"1.1 1.2 1.3"
+
+    # Same, but with qualified thread IDs.
+    thr_apply_info_thr "1.1 1.2 1.3 2.1 2.2" \
+	"1.1 1.2 1.3 2.1 2.2"
+
+    # Test a thread number range.
+    thr_apply_info_thr "1-3" \
+	"1.1 1.2 1.3"
+
+    # Same, but using a qualified range.
+    thr_apply_info_thr "1.1-3" \
+	"1.1 1.2 1.3"
+
+    # A mix of qualified and unqualified thread IDs/ranges.
+    thr_apply_info_thr "1.1 2-3" \
+	"1.1 1.2 1.3"
+
+    thr_apply_info_thr "1 1.2-3" \
+	"1.1 1.2 1.3"
+
+    # Likewise, but mix inferiors too.
+    thr_apply_info_thr "2.1 2-3" \
+	"1.2 1.3 2.1" \
+	"2.1 1.2 1.3"
+
+    # Multiple ranges with mixed explicit inferiors.
+    thr_apply_info_thr "1.1-2 2.2-3" \
+	"1.1 1.2 2.2 2.3"
+
+    # Now test a set of invalid thread IDs/ranges.
+
+    thr_apply_info_thr_invalid "1." \
+	"1."
+
+    thr_apply_info_thr_invalid "1-3 1." \
+	"1."
+
+    thr_apply_info_thr_invalid "1.1.1" \
+	"1.1.1"
+
+    thr_apply_info_thr_invalid "2 1.1.1" \
+	"1.1.1"
+
+    thr_apply_info_thr_invalid "1.1.1 2" \
+	"1.1.1 2"
+
+    thr_apply_info_thr_invalid "1-2.1" \
+	"1-2.1"
+
+    thr_apply_info_thr_error "1-0" "inverted range"
+    thr_apply_info_thr_error "1.1-0" "inverted range"
+
+    thr_apply_info_thr_error "1-" "inverted range"
+    thr_apply_info_thr_error "1.1-" "inverted range"
+
+    thr_apply_info_thr_error "2-1" "inverted range"
+    thr_apply_info_thr_error "1.2-1" "inverted range"
+
+    thr_apply_info_thr_error "-1" "negative value"
+    thr_apply_info_thr_error "1.-1" "negative value"
+
+    # Check that we do parse the inferior number and don't confuse it.
+    gdb_test "info threads 3.1" \
+	"No threads match '3.1'\."
+}
+
+if { ![skip_python_tests] } {
+    with_test_prefix "python" {
+	# Check that InferiorThread.num returns the expected number.
+	gdb_py_test_silent_cmd "python t0 = gdb.selected_thread ()" \
+	    "test gdb.selected_thread" 1
+	gdb_test "python print ('result = %s' % t0.num)" " = 3" \
+	    "test InferiorThread.num"
+    }
+}
+
+# Remove the second inferior and confirm that GDB goes back to showing
+# single-number thread IDs.
+with_test_prefix "back to one inferior" {
+    gdb_test "kill inferior 2" "" "kill inferior 2" "Kill the program being debugged.*" "y"
+    gdb_test "thread 1.1" "Switching to thread 1\.1 .*"
+    gdb_test "remove-inferior 2" ".*" "remove inferior 2"
+
+    # "info threads" while there's only inferior 1 should show
+    # single-number thread IDs.
+    info_threads "" "1 2 3"
+
+    gdb_test "thread" "Current thread is 1 .*"
+}
+
+# Add another inferior and remove inferior 1.  Since even though
+# there's a single inferior, its number is not 1, GDB should show
+# inferior-qualified thread IDs.
+with_test_prefix "single-inferior but not initial" {
+    # Add another inferior.
+    gdb_test "add-inferior" "Added inferior 3.*" "add empty inferior"
+
+    # Now that we'd added another inferior, thread IDs should show the
+    # inferior number.
+    info_threads "" "1.1 1.2 1.3" \
+	"info threads with multiple inferiors"
+
+    gdb_test "thread" "Current thread is 1\.1 .*"
+
+    gdb_test "inferior 3" "Switching to inferior 3 .*" "switch to inferior 3"
+    gdb_test "file ${binfile}" ".*" "load file in inferior 3"
+
+    runto_main
+
+    gdb_test "remove-inferior 1" ".*" "remove inferior 1"
+
+    # Even though we have a single inferior, its number is > 1, so
+    # thread IDs should include the inferior number.
+    info_threads "" "3.1" \
+	"info threads with single inferior"
+
+    gdb_test "thread" "Current thread is 3\.1 .*" "thread again"
+}