[PATCH v2] inferior without argument prints detail of current inferior

[PATCH v2] inferior without argument prints detail of current inferior

[Lancelot SIX via Gdb-patches]

This patch makes the inferior command display information about the
current inferior when called with no argument. This behavior is similar
to the one of the thread command.

This contribution is inspired by an item in
https://sourceware.org/gdb/wiki/ProjectIdeas

Before patch:

    (gdb) info inferior
      Num  Description       Connection           Executable
    * 1    process 19221     1 (native)           /home/lsix/tmp/a.out
      2    process 19239     1 (native)           /home/lsix/tmp/a.out
    (gdb) inferior 2
    [Switching to inferior 2 [process 19239] (/home/lsix/tmp/a.out)]
    [Switching to thread 2.1 (process 19239)]
    #0  0x0000000000401146 in main ()
    (gdb) inferior
    Argument required (expression to compute).

After patch:

    (gdb) info inferior
      Num  Description       Connection           Executable
    * 1    process 18699     1 (native)           /home/lsix/tmp/a.out
      2    process 18705     1 (native)           /home/lsix/tmp/a.out
    (gdb) inferior 2
    [Switching to inferior 2 [process 18705] (/home/lsix/tmp/a.out)]
    [Switching to thread 2.1 (process 18705)]
    #0  0x0000000000401146 in main ()
    (gdb) inferior
    [Current inferior is 2 [process 18705] (/home/lsix/tmp/a.out)]

My copyright assignment request is currently in progress.

gdb/doc/ChangeLog:

2020-12-16  Lancelot SIX  <lsix@lancelotsix.com>

	* gdb.texinfo: Document the inferior command when used without
    argument

gdb/ChangeLog:

2020-12-16  Lancelot SIX  <lsix@lancelotsix.com>

	* inferior.c (inferior_command): When no argument is given to the
	inferior command, display info about the currently selected
	inferior.

gdb/testsuite/ChangeLog:

2020-12-16  Lancelot SIX  <lsix@lancelotsix.com>

	* gdb.base/inferior-noarg.c: New test.
	* gdb.base/inferior-noarg.exp: New test.
---
 gdb/doc/gdb.texinfo                       | 16 +++++++
 gdb/inferior.c                            | 58 +++++++++++++++--------
 gdb/testsuite/gdb.base/inferior-noarg.c   | 22 +++++++++
 gdb/testsuite/gdb.base/inferior-noarg.exp | 36 ++++++++++++++
 4 files changed, 111 insertions(+), 21 deletions(-)
 create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.c
 create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.exp

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 5b6ac8549b..c9ee0b87f2 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -3202,6 +3202,22 @@ For example,
   2    process 2307      2 (extended-remote host:10000)  hello
 @end smallexample
 
+To get informations about the current inferior, use @code{inferior}:
+
+@table @code
+@kindex inferior
+@item inferior
+Shows information about the current inferior.
+
+For example,
+@end table
+@c end table here to get a little more width for example
+
+@smallexample
+(@value{GDBP}) inferior
+[Current inferior is 1 [process 3401] (helloworld)]
+@end smallexample
+
 To find out what open target connections exist at any moment, use
 @w{@code{info connections}}:
 
diff --git a/gdb/inferior.c b/gdb/inferior.c
index a6652b6920..9bd6629af9 100644
--- a/gdb/inferior.c
+++ b/gdb/inferior.c
@@ -635,34 +635,50 @@ inferior_command (const char *args, int from_tty)
   struct inferior *inf;
   int num;
 
-  num = parse_and_eval_long (args);
-
-  inf = find_inferior_id (num);
-  if (inf == NULL)
-    error (_("Inferior ID %d not known."), num);
-
-  if (inf->pid != 0)
+  if (args == nullptr)
     {
-      if (inf != current_inferior ())
-	{
-	  thread_info *tp = any_thread_of_inferior (inf);
-	  if (tp == NULL)
-	    error (_("Inferior has no threads."));
+      inf = current_inferior ();
+      gdb_assert (inf != nullptr);
+      const char *filename = inf->pspace->exec_filename.get ();
 
-	  switch_to_thread (tp);
-	}
+      if (filename == nullptr)
+	filename = _("<noexec>");
 
-      gdb::observers::user_selected_context_changed.notify
-	(USER_SELECTED_INFERIOR
-	 | USER_SELECTED_THREAD
-	 | USER_SELECTED_FRAME);
+      printf_filtered (_("[Current inferior is %d [%s] (%s)]\n"),
+		       inf->num, inferior_pid_to_str (inf->pid).c_str (),
+		       filename);
     }
   else
     {
-      switch_to_inferior_no_thread (inf);
+      num = parse_and_eval_long (args);
+
+      inf = find_inferior_id (num);
+      if (inf == NULL)
+	error (_("Inferior ID %d not known."), num);
+
+      if (inf->pid != 0)
+	{
+	  if (inf != current_inferior ())
+	    {
+	      thread_info *tp = any_thread_of_inferior (inf);
+	      if (tp == NULL)
+		error (_("Inferior has no threads."));
 
-      gdb::observers::user_selected_context_changed.notify
-	(USER_SELECTED_INFERIOR);
+	      switch_to_thread (tp);
+	    }
+
+	  gdb::observers::user_selected_context_changed.notify
+	    (USER_SELECTED_INFERIOR
+	     | USER_SELECTED_THREAD
+	     | USER_SELECTED_FRAME);
+	}
+      else
+	{
+	  switch_to_inferior_no_thread (inf);
+
+	  gdb::observers::user_selected_context_changed.notify
+	    (USER_SELECTED_INFERIOR);
+	}
     }
 }
 
diff --git a/gdb/testsuite/gdb.base/inferior-noarg.c b/gdb/testsuite/gdb.base/inferior-noarg.c
new file mode 100644
index 0000000000..9d7b2f1a4c
--- /dev/null
+++ b/gdb/testsuite/gdb.base/inferior-noarg.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2020 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/>.  */
+
+int
+main (void)
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/inferior-noarg.exp b/gdb/testsuite/gdb.base/inferior-noarg.exp
new file mode 100644
index 0000000000..38842aa7d8
--- /dev/null
+++ b/gdb/testsuite/gdb.base/inferior-noarg.exp
@@ -0,0 +1,36 @@
+# Copyright 2020 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/>.
+
+# This test case checks that the 'inferior' command, when given no
+# argument, displays information about the inferior currently active.
+
+standard_testfile
+
+if { [prepare_for_testing "failed to prepare" \
+	${testfile} ${srcfile}] } {
+    return
+}
+
+gdb_test "inferior" "\[Current inferior is 1 \[<null>\] (.*)\]" "inferior not running"
+
+if { ![runto_main] } {
+    untested "could not run to main"
+    return
+}
+
+gdb_test "inferior" "\[Current inferior is 1 \[process .*\] (.*)\]" "inferior running"
+gdb_test "clone-inferior" "Added inferior 2.*" "create new inferior"
+gdb_test "inferior 2" "\[Switching to inferior 2 \[<null>\] (.*)]" "change inferior"
+gdb_test "inferior" "\[Current inferior is 2 \[<null>\] (.*)\]" "show new inferior"
-- 
2.29.2

Re: [PATCH v2] inferior without argument prints detail of current inferior

[Simon Marchi via Gdb-patches]

On 2020-12-18 5:04 p.m., Lancelot SIX via Gdb-patches wrote:
> This patch makes the inferior command display information about the
> current inferior when called with no argument. This behavior is similar
> to the one of the thread command.
> 
> This contribution is inspired by an item in
> https://sourceware.org/gdb/wiki/ProjectIdeas
> 
> Before patch:
> 
>     (gdb) info inferior
>       Num  Description       Connection           Executable
>     * 1    process 19221     1 (native)           /home/lsix/tmp/a.out
>       2    process 19239     1 (native)           /home/lsix/tmp/a.out
>     (gdb) inferior 2
>     [Switching to inferior 2 [process 19239] (/home/lsix/tmp/a.out)]
>     [Switching to thread 2.1 (process 19239)]
>     #0  0x0000000000401146 in main ()
>     (gdb) inferior
>     Argument required (expression to compute).
> 
> After patch:
> 
>     (gdb) info inferior
>       Num  Description       Connection           Executable
>     * 1    process 18699     1 (native)           /home/lsix/tmp/a.out
>       2    process 18705     1 (native)           /home/lsix/tmp/a.out
>     (gdb) inferior 2
>     [Switching to inferior 2 [process 18705] (/home/lsix/tmp/a.out)]
>     [Switching to thread 2.1 (process 18705)]
>     #0  0x0000000000401146 in main ()
>     (gdb) inferior
>     [Current inferior is 2 [process 18705] (/home/lsix/tmp/a.out)]
> 
> My copyright assignment request is currently in progress.
> 
> gdb/doc/ChangeLog:
> 
> 2020-12-16  Lancelot SIX  <lsix@lancelotsix.com>
> 
> 	* gdb.texinfo: Document the inferior command when used without
>     argument

For the ChangeLog entity in the entry here, find the nearest @node
that contains the change.

> 
> gdb/ChangeLog:
> 
> 2020-12-16  Lancelot SIX  <lsix@lancelotsix.com>
> 
> 	* inferior.c (inferior_command): When no argument is given to the
> 	inferior command, display info about the currently selected
> 	inferior.
> 
> gdb/testsuite/ChangeLog:
> 
> 2020-12-16  Lancelot SIX  <lsix@lancelotsix.com>
> 
> 	* gdb.base/inferior-noarg.c: New test.
> 	* gdb.base/inferior-noarg.exp: New test.
> ---
>  gdb/doc/gdb.texinfo                       | 16 +++++++
>  gdb/inferior.c                            | 58 +++++++++++++++--------
>  gdb/testsuite/gdb.base/inferior-noarg.c   | 22 +++++++++
>  gdb/testsuite/gdb.base/inferior-noarg.exp | 36 ++++++++++++++
>  4 files changed, 111 insertions(+), 21 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.c
>  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.exp
> 
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 5b6ac8549b..c9ee0b87f2 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -3202,6 +3202,22 @@ For example,
>    2    process 2307      2 (extended-remote host:10000)  hello
>  @end smallexample
>  
> +To get informations about the current inferior, use @code{inferior}:
> +
> +@table @code
> +@kindex inferior
> +@item inferior
> +Shows information about the current inferior.
> +
> +For example,
> +@end table
> +@c end table here to get a little more width for example
> +
> +@smallexample
> +(@value{GDBP}) inferior
> +[Current inferior is 1 [process 3401] (helloworld)]
> +@end smallexample
> +
>  To find out what open target connections exist at any moment, use
>  @w{@code{info connections}}:

The documentation bits will have to be reviewed by Eli.

> diff --git a/gdb/testsuite/gdb.base/inferior-noarg.c b/gdb/testsuite/gdb.base/inferior-noarg.c
> new file mode 100644
> index 0000000000..9d7b2f1a4c
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/inferior-noarg.c
> @@ -0,0 +1,22 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2020 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/>.  */
> +
> +int
> +main (void)
> +{
> +  return 0;
> +}

I kinda recall that we had one dummy C file that we re-used instead of
creating more trivial ones like that.  But I can't find it, so this LGTM
unless someone finds it.

Otherwise, let's patiently wait for your copyright assignment.

Simon

[PATCH v3] inferior without argument prints detail of current inferior

[Lancelot SIX via Gdb-patches]

This patch makes the inferior command display information about the
current inferior when called with no argument. This behavior is similar
to the one of the thread command.

This contribution is inspired by an item in
https://sourceware.org/gdb/wiki/ProjectIdeas

Before patch:

    (gdb) info inferior
      Num  Description       Connection           Executable
    * 1    process 19221     1 (native)           /home/lsix/tmp/a.out
      2    process 19239     1 (native)           /home/lsix/tmp/a.out
    (gdb) inferior 2
    [Switching to inferior 2 [process 19239] (/home/lsix/tmp/a.out)]
    [Switching to thread 2.1 (process 19239)]
    #0  0x0000000000401146 in main ()
    (gdb) inferior
    Argument required (expression to compute).

After patch:

    (gdb) info inferior
      Num  Description       Connection           Executable
    * 1    process 18699     1 (native)           /home/lsix/tmp/a.out
      2    process 18705     1 (native)           /home/lsix/tmp/a.out
    (gdb) inferior 2
    [Switching to inferior 2 [process 18705] (/home/lsix/tmp/a.out)]
    [Switching to thread 2.1 (process 18705)]
    #0  0x0000000000401146 in main ()
    (gdb) inferior
    [Current inferior is 2 [process 18705] (/home/lsix/tmp/a.out)]

Changes from V1:
  * Add test.

Change from V2:
  * Fix gdb/doc/ChangeLog entry.
  * My copyright assignment has been signed.

gdb/doc/ChangeLog:

	* gdb.texinfo (Inferiors Connections and Programs): Document the
	inferior command when used without argument.

gdb/ChangeLog:

	* inferior.c (inferior_command): When no argument is given to the
	inferior command, display info about the currently selected
	inferior.

gdb/testsuite/ChangeLog:

	* gdb.base/inferior-noarg.c: New test.
	* gdb.base/inferior-noarg.exp: New test.

---
---
 gdb/doc/gdb.texinfo                       | 16 +++++++
 gdb/inferior.c                            | 58 +++++++++++++++--------
 gdb/testsuite/gdb.base/inferior-noarg.c   | 22 +++++++++
 gdb/testsuite/gdb.base/inferior-noarg.exp | 36 ++++++++++++++
 4 files changed, 111 insertions(+), 21 deletions(-)
 create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.c
 create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.exp

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 69fa6b709b..a97a342e9d 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -3202,6 +3202,22 @@ For example,
   2    process 2307      2 (extended-remote host:10000)  hello
 @end smallexample
 
+To get informations about the current inferior, use @code{inferior}:
+
+@table @code
+@kindex inferior
+@item inferior
+Shows information about the current inferior.
+
+For example,
+@end table
+@c end table here to get a little more width for example
+
+@smallexample
+(@value{GDBP}) inferior
+[Current inferior is 1 [process 3401] (helloworld)]
+@end smallexample
+
 To find out what open target connections exist at any moment, use
 @w{@code{info connections}}:
 
diff --git a/gdb/inferior.c b/gdb/inferior.c
index 3ff0512c38..49f869a4c7 100644
--- a/gdb/inferior.c
+++ b/gdb/inferior.c
@@ -635,34 +635,50 @@ inferior_command (const char *args, int from_tty)
   struct inferior *inf;
   int num;
 
-  num = parse_and_eval_long (args);
-
-  inf = find_inferior_id (num);
-  if (inf == NULL)
-    error (_("Inferior ID %d not known."), num);
-
-  if (inf->pid != 0)
+  if (args == nullptr)
     {
-      if (inf != current_inferior ())
-	{
-	  thread_info *tp = any_thread_of_inferior (inf);
-	  if (tp == NULL)
-	    error (_("Inferior has no threads."));
+      inf = current_inferior ();
+      gdb_assert (inf != nullptr);
+      const char *filename = inf->pspace->exec_filename.get ();
 
-	  switch_to_thread (tp);
-	}
+      if (filename == nullptr)
+	filename = _("<noexec>");
 
-      gdb::observers::user_selected_context_changed.notify
-	(USER_SELECTED_INFERIOR
-	 | USER_SELECTED_THREAD
-	 | USER_SELECTED_FRAME);
+      printf_filtered (_("[Current inferior is %d [%s] (%s)]\n"),
+		       inf->num, inferior_pid_to_str (inf->pid).c_str (),
+		       filename);
     }
   else
     {
-      switch_to_inferior_no_thread (inf);
+      num = parse_and_eval_long (args);
+
+      inf = find_inferior_id (num);
+      if (inf == NULL)
+	error (_("Inferior ID %d not known."), num);
+
+      if (inf->pid != 0)
+	{
+	  if (inf != current_inferior ())
+	    {
+	      thread_info *tp = any_thread_of_inferior (inf);
+	      if (tp == NULL)
+		error (_("Inferior has no threads."));
 
-      gdb::observers::user_selected_context_changed.notify
-	(USER_SELECTED_INFERIOR);
+	      switch_to_thread (tp);
+	    }
+
+	  gdb::observers::user_selected_context_changed.notify
+	    (USER_SELECTED_INFERIOR
+	     | USER_SELECTED_THREAD
+	     | USER_SELECTED_FRAME);
+	}
+      else
+	{
+	  switch_to_inferior_no_thread (inf);
+
+	  gdb::observers::user_selected_context_changed.notify
+	    (USER_SELECTED_INFERIOR);
+	}
     }
 }
 
diff --git a/gdb/testsuite/gdb.base/inferior-noarg.c b/gdb/testsuite/gdb.base/inferior-noarg.c
new file mode 100644
index 0000000000..9d7b2f1a4c
--- /dev/null
+++ b/gdb/testsuite/gdb.base/inferior-noarg.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2020 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/>.  */
+
+int
+main (void)
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/inferior-noarg.exp b/gdb/testsuite/gdb.base/inferior-noarg.exp
new file mode 100644
index 0000000000..38842aa7d8
--- /dev/null
+++ b/gdb/testsuite/gdb.base/inferior-noarg.exp
@@ -0,0 +1,36 @@
+# Copyright 2020 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/>.
+
+# This test case checks that the 'inferior' command, when given no
+# argument, displays information about the inferior currently active.
+
+standard_testfile
+
+if { [prepare_for_testing "failed to prepare" \
+	${testfile} ${srcfile}] } {
+    return
+}
+
+gdb_test "inferior" "\[Current inferior is 1 \[<null>\] (.*)\]" "inferior not running"
+
+if { ![runto_main] } {
+    untested "could not run to main"
+    return
+}
+
+gdb_test "inferior" "\[Current inferior is 1 \[process .*\] (.*)\]" "inferior running"
+gdb_test "clone-inferior" "Added inferior 2.*" "create new inferior"
+gdb_test "inferior 2" "\[Switching to inferior 2 \[<null>\] (.*)]" "change inferior"
+gdb_test "inferior" "\[Current inferior is 2 \[<null>\] (.*)\]" "show new inferior"
-- 
2.29.2

Re: [PATCH v3] inferior without argument prints detail of current inferior

[Simon Marchi via Gdb-patches]

On 2021-01-09 4:24 p.m., Lancelot SIX via Gdb-patches wrote:
> This patch makes the inferior command display information about the
> current inferior when called with no argument. This behavior is similar
> to the one of the thread command.
> 
> This contribution is inspired by an item in
> https://sourceware.org/gdb/wiki/ProjectIdeas
> 
> Before patch:
> 
>     (gdb) info inferior
>       Num  Description       Connection           Executable
>     * 1    process 19221     1 (native)           /home/lsix/tmp/a.out
>       2    process 19239     1 (native)           /home/lsix/tmp/a.out
>     (gdb) inferior 2
>     [Switching to inferior 2 [process 19239] (/home/lsix/tmp/a.out)]
>     [Switching to thread 2.1 (process 19239)]
>     #0  0x0000000000401146 in main ()
>     (gdb) inferior
>     Argument required (expression to compute).
> 
> After patch:
> 
>     (gdb) info inferior
>       Num  Description       Connection           Executable
>     * 1    process 18699     1 (native)           /home/lsix/tmp/a.out
>       2    process 18705     1 (native)           /home/lsix/tmp/a.out
>     (gdb) inferior 2
>     [Switching to inferior 2 [process 18705] (/home/lsix/tmp/a.out)]
>     [Switching to thread 2.1 (process 18705)]
>     #0  0x0000000000401146 in main ()
>     (gdb) inferior
>     [Current inferior is 2 [process 18705] (/home/lsix/tmp/a.out)]
> 
> Changes from V1:
>   * Add test.
> 
> Change from V2:
>   * Fix gdb/doc/ChangeLog entry.
>   * My copyright assignment has been signed.
> 
> gdb/doc/ChangeLog:
> 
> 	* gdb.texinfo (Inferiors Connections and Programs): Document the
> 	inferior command when used without argument.
> 
> gdb/ChangeLog:
> 
> 	* inferior.c (inferior_command): When no argument is given to the
> 	inferior command, display info about the currently selected
> 	inferior.
> 
> gdb/testsuite/ChangeLog:
> 
> 	* gdb.base/inferior-noarg.c: New test.
> 	* gdb.base/inferior-noarg.exp: New test.
> 
> ---
> ---
>  gdb/doc/gdb.texinfo                       | 16 +++++++
>  gdb/inferior.c                            | 58 +++++++++++++++--------
>  gdb/testsuite/gdb.base/inferior-noarg.c   | 22 +++++++++
>  gdb/testsuite/gdb.base/inferior-noarg.exp | 36 ++++++++++++++
>  4 files changed, 111 insertions(+), 21 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.c
>  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.exp
> 
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 69fa6b709b..a97a342e9d 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -3202,6 +3202,22 @@ For example,
>    2    process 2307      2 (extended-remote host:10000)  hello
>  @end smallexample
>  
> +To get informations about the current inferior, use @code{inferior}:
> +
> +@table @code
> +@kindex inferior
> +@item inferior
> +Shows information about the current inferior.
> +
> +For example,
> +@end table
> +@c end table here to get a little more width for example
> +
> +@smallexample
> +(@value{GDBP}) inferior
> +[Current inferior is 1 [process 3401] (helloworld)]
> +@end smallexample
> +
>  To find out what open target connections exist at any moment, use
>  @w{@code{info connections}}:
>  
> diff --git a/gdb/inferior.c b/gdb/inferior.c
> index 3ff0512c38..49f869a4c7 100644
> --- a/gdb/inferior.c
> +++ b/gdb/inferior.c
> @@ -635,34 +635,50 @@ inferior_command (const char *args, int from_tty)
>    struct inferior *inf;
>    int num;
>  
> -  num = parse_and_eval_long (args);
> -
> -  inf = find_inferior_id (num);
> -  if (inf == NULL)
> -    error (_("Inferior ID %d not known."), num);
> -
> -  if (inf->pid != 0)
> +  if (args == nullptr)
>      {
> -      if (inf != current_inferior ())
> -	{
> -	  thread_info *tp = any_thread_of_inferior (inf);
> -	  if (tp == NULL)
> -	    error (_("Inferior has no threads."));
> +      inf = current_inferior ();
> +      gdb_assert (inf != nullptr);
> +      const char *filename = inf->pspace->exec_filename.get ();
>  
> -	  switch_to_thread (tp);
> -	}
> +      if (filename == nullptr)
> +	filename = _("<noexec>");
>  
> -      gdb::observers::user_selected_context_changed.notify
> -	(USER_SELECTED_INFERIOR
> -	 | USER_SELECTED_THREAD
> -	 | USER_SELECTED_FRAME);
> +      printf_filtered (_("[Current inferior is %d [%s] (%s)]\n"),
> +		       inf->num, inferior_pid_to_str (inf->pid).c_str (),
> +		       filename);
>      }
>    else
>      {
> -      switch_to_inferior_no_thread (inf);
> +      num = parse_and_eval_long (args);
> +
> +      inf = find_inferior_id (num);
> +      if (inf == NULL)
> +	error (_("Inferior ID %d not known."), num);
> +
> +      if (inf->pid != 0)
> +	{
> +	  if (inf != current_inferior ())
> +	    {
> +	      thread_info *tp = any_thread_of_inferior (inf);
> +	      if (tp == NULL)
> +		error (_("Inferior has no threads."));
>  
> -      gdb::observers::user_selected_context_changed.notify
> -	(USER_SELECTED_INFERIOR);
> +	      switch_to_thread (tp);
> +	    }
> +
> +	  gdb::observers::user_selected_context_changed.notify
> +	    (USER_SELECTED_INFERIOR
> +	     | USER_SELECTED_THREAD
> +	     | USER_SELECTED_FRAME);
> +	}
> +      else
> +	{
> +	  switch_to_inferior_no_thread (inf);
> +
> +	  gdb::observers::user_selected_context_changed.notify
> +	    (USER_SELECTED_INFERIOR);
> +	}
>      }
>  }
>  
> diff --git a/gdb/testsuite/gdb.base/inferior-noarg.c b/gdb/testsuite/gdb.base/inferior-noarg.c
> new file mode 100644
> index 0000000000..9d7b2f1a4c
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/inferior-noarg.c
> @@ -0,0 +1,22 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2020 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/>.  */
> +
> +int
> +main (void)
> +{
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.base/inferior-noarg.exp b/gdb/testsuite/gdb.base/inferior-noarg.exp
> new file mode 100644
> index 0000000000..38842aa7d8
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/inferior-noarg.exp
> @@ -0,0 +1,36 @@
> +# Copyright 2020 Free Software Foundation, Inc.

Change both copyright years to 2021.

> +
> +# 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/>.
> +
> +# This test case checks that the 'inferior' command, when given no
> +# argument, displays information about the inferior currently active.
> +
> +standard_testfile
> +
> +if { [prepare_for_testing "failed to prepare" \
> +	${testfile} ${srcfile}] } {
> +    return
> +}
> +
> +gdb_test "inferior" "\[Current inferior is 1 \[<null>\] (.*)\]" "inferior not running"
> +
> +if { ![runto_main] } {
> +    untested "could not run to main"
> +    return
> +}
> +
> +gdb_test "inferior" "\[Current inferior is 1 \[process .*\] (.*)\]" "inferior running"

I'm worried that this regexp is a little bit too specific, as targets can
implement the `pid_to_str` method and decide to call their "process"
something else.  "process 1234" is just the default, done by normal_pid_to_str.

I'm fine with merging it though, as that will probably work with all in-tree
targets.  The only one I found where it wouldn't work in bsd_kvm_target, which
does:

std::string
bsd_kvm_target::pid_to_str (ptid_t ptid)
{
  return "<kvm>";
}

But I don't think the testsuite is ran against that target anywhere... and in
any case it's an easy fix if we stumble on a target for which it doesn't work.

Do you have push access?  If you plan on sending more patches, it would make
sense for you to have it, so you can push your own patches once approved.  Let
me know if you'd like to do that.

Simon

Re: [PATCH v3] inferior without argument prints detail of current inferior

[Lancelot SIX via Gdb-patches]

On Sun, Jan 10, 2021 at 11:00:28AM -0500, Simon Marchi wrote:
> 
> 
> On 2021-01-09 4:24 p.m., Lancelot SIX via Gdb-patches wrote:
> > This patch makes the inferior command display information about the
> > current inferior when called with no argument. This behavior is similar
> > to the one of the thread command.
> > 
> > This contribution is inspired by an item in
> > https://sourceware.org/gdb/wiki/ProjectIdeas
> > 
> > Before patch:
> > 
> >     (gdb) info inferior
> >       Num  Description       Connection           Executable
> >     * 1    process 19221     1 (native)           /home/lsix/tmp/a.out
> >       2    process 19239     1 (native)           /home/lsix/tmp/a.out
> >     (gdb) inferior 2
> >     [Switching to inferior 2 [process 19239] (/home/lsix/tmp/a.out)]
> >     [Switching to thread 2.1 (process 19239)]
> >     #0  0x0000000000401146 in main ()
> >     (gdb) inferior
> >     Argument required (expression to compute).
> > 
> > After patch:
> > 
> >     (gdb) info inferior
> >       Num  Description       Connection           Executable
> >     * 1    process 18699     1 (native)           /home/lsix/tmp/a.out
> >       2    process 18705     1 (native)           /home/lsix/tmp/a.out
> >     (gdb) inferior 2
> >     [Switching to inferior 2 [process 18705] (/home/lsix/tmp/a.out)]
> >     [Switching to thread 2.1 (process 18705)]
> >     #0  0x0000000000401146 in main ()
> >     (gdb) inferior
> >     [Current inferior is 2 [process 18705] (/home/lsix/tmp/a.out)]
> > 
> > Changes from V1:
> >   * Add test.
> > 
> > Change from V2:
> >   * Fix gdb/doc/ChangeLog entry.
> >   * My copyright assignment has been signed.
> > 
> > gdb/doc/ChangeLog:
> > 
> > 	* gdb.texinfo (Inferiors Connections and Programs): Document the
> > 	inferior command when used without argument.
> > 
> > gdb/ChangeLog:
> > 
> > 	* inferior.c (inferior_command): When no argument is given to the
> > 	inferior command, display info about the currently selected
> > 	inferior.
> > 
> > gdb/testsuite/ChangeLog:
> > 
> > 	* gdb.base/inferior-noarg.c: New test.
> > 	* gdb.base/inferior-noarg.exp: New test.
> > 
> > ---
> > ---
> >  gdb/doc/gdb.texinfo                       | 16 +++++++
> >  gdb/inferior.c                            | 58 +++++++++++++++--------
> >  gdb/testsuite/gdb.base/inferior-noarg.c   | 22 +++++++++
> >  gdb/testsuite/gdb.base/inferior-noarg.exp | 36 ++++++++++++++
> >  4 files changed, 111 insertions(+), 21 deletions(-)
> >  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.c
> >  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.exp
> > 
> > diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> > index 69fa6b709b..a97a342e9d 100644
> > --- a/gdb/doc/gdb.texinfo
> > +++ b/gdb/doc/gdb.texinfo
> > @@ -3202,6 +3202,22 @@ For example,
> >    2    process 2307      2 (extended-remote host:10000)  hello
> >  @end smallexample
> >  
> > +To get informations about the current inferior, use @code{inferior}:
> > +
> > +@table @code
> > +@kindex inferior
> > +@item inferior
> > +Shows information about the current inferior.
> > +
> > +For example,
> > +@end table
> > +@c end table here to get a little more width for example
> > +
> > +@smallexample
> > +(@value{GDBP}) inferior
> > +[Current inferior is 1 [process 3401] (helloworld)]
> > +@end smallexample
> > +
> >  To find out what open target connections exist at any moment, use
> >  @w{@code{info connections}}:
> >  
> > diff --git a/gdb/inferior.c b/gdb/inferior.c
> > index 3ff0512c38..49f869a4c7 100644
> > --- a/gdb/inferior.c
> > +++ b/gdb/inferior.c
> > @@ -635,34 +635,50 @@ inferior_command (const char *args, int from_tty)
> >    struct inferior *inf;
> >    int num;
> >  
> > -  num = parse_and_eval_long (args);
> > -
> > -  inf = find_inferior_id (num);
> > -  if (inf == NULL)
> > -    error (_("Inferior ID %d not known."), num);
> > -
> > -  if (inf->pid != 0)
> > +  if (args == nullptr)
> >      {
> > -      if (inf != current_inferior ())
> > -	{
> > -	  thread_info *tp = any_thread_of_inferior (inf);
> > -	  if (tp == NULL)
> > -	    error (_("Inferior has no threads."));
> > +      inf = current_inferior ();
> > +      gdb_assert (inf != nullptr);
> > +      const char *filename = inf->pspace->exec_filename.get ();
> >  
> > -	  switch_to_thread (tp);
> > -	}
> > +      if (filename == nullptr)
> > +	filename = _("<noexec>");
> >  
> > -      gdb::observers::user_selected_context_changed.notify
> > -	(USER_SELECTED_INFERIOR
> > -	 | USER_SELECTED_THREAD
> > -	 | USER_SELECTED_FRAME);
> > +      printf_filtered (_("[Current inferior is %d [%s] (%s)]\n"),
> > +		       inf->num, inferior_pid_to_str (inf->pid).c_str (),
> > +		       filename);
> >      }
> >    else
> >      {
> > -      switch_to_inferior_no_thread (inf);
> > +      num = parse_and_eval_long (args);
> > +
> > +      inf = find_inferior_id (num);
> > +      if (inf == NULL)
> > +	error (_("Inferior ID %d not known."), num);
> > +
> > +      if (inf->pid != 0)
> > +	{
> > +	  if (inf != current_inferior ())
> > +	    {
> > +	      thread_info *tp = any_thread_of_inferior (inf);
> > +	      if (tp == NULL)
> > +		error (_("Inferior has no threads."));
> >  
> > -      gdb::observers::user_selected_context_changed.notify
> > -	(USER_SELECTED_INFERIOR);
> > +	      switch_to_thread (tp);
> > +	    }
> > +
> > +	  gdb::observers::user_selected_context_changed.notify
> > +	    (USER_SELECTED_INFERIOR
> > +	     | USER_SELECTED_THREAD
> > +	     | USER_SELECTED_FRAME);
> > +	}
> > +      else
> > +	{
> > +	  switch_to_inferior_no_thread (inf);
> > +
> > +	  gdb::observers::user_selected_context_changed.notify
> > +	    (USER_SELECTED_INFERIOR);
> > +	}
> >      }
> >  }
> >  
> > diff --git a/gdb/testsuite/gdb.base/inferior-noarg.c b/gdb/testsuite/gdb.base/inferior-noarg.c
> > new file mode 100644
> > index 0000000000..9d7b2f1a4c
> > --- /dev/null
> > +++ b/gdb/testsuite/gdb.base/inferior-noarg.c
> > @@ -0,0 +1,22 @@
> > +/* This testcase is part of GDB, the GNU debugger.
> > +
> > +   Copyright 2020 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/>.  */
> > +
> > +int
> > +main (void)
> > +{
> > +  return 0;
> > +}
> > diff --git a/gdb/testsuite/gdb.base/inferior-noarg.exp b/gdb/testsuite/gdb.base/inferior-noarg.exp
> > new file mode 100644
> > index 0000000000..38842aa7d8
> > --- /dev/null
> > +++ b/gdb/testsuite/gdb.base/inferior-noarg.exp
> > @@ -0,0 +1,36 @@
> > +# Copyright 2020 Free Software Foundation, Inc.
> 
> Change both copyright years to 2021.
> 
> > +
> > +# 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/>.
> > +
> > +# This test case checks that the 'inferior' command, when given no
> > +# argument, displays information about the inferior currently active.
> > +
> > +standard_testfile
> > +
> > +if { [prepare_for_testing "failed to prepare" \
> > +	${testfile} ${srcfile}] } {
> > +    return
> > +}
> > +
> > +gdb_test "inferior" "\[Current inferior is 1 \[<null>\] (.*)\]" "inferior not running"
> > +
> > +if { ![runto_main] } {
> > +    untested "could not run to main"
> > +    return
> > +}
> > +
> > +gdb_test "inferior" "\[Current inferior is 1 \[process .*\] (.*)\]" "inferior running"
> 
> I'm worried that this regexp is a little bit too specific, as targets can
> implement the `pid_to_str` method and decide to call their "process"
> something else.  "process 1234" is just the default, done by normal_pid_to_str.
> 
> I'm fine with merging it though, as that will probably work with all in-tree
> targets.  The only one I found where it wouldn't work in bsd_kvm_target, which
> does:
> 
> std::string
> bsd_kvm_target::pid_to_str (ptid_t ptid)
> {
>   return "<kvm>";
> }
> 

I’ll send shortly an updated version that removes this behavior
assumption and accept anything pid_to_str can throw at it.

> But I don't think the testsuite is ran against that target anywhere... and in
> any case it's an easy fix if we stumble on a target for which it doesn't work.
> 
> Do you have push access?  If you plan on sending more patches, it would make
> sense for you to have it, so you can push your own patches once approved.  Let
> me know if you'd like to do that.

No, I do not, nor do I have an account on sourceware.org. Given that
I’ll try to continue to contribute (to the extend of what my spare time
allows me to), I guess this would make sence!  Should I follow the
procedure describe in https://sourceware.org/cgi-bin/pdw/ps_form.cgi and
provide your email as reference?

Thanks
Lancelot.

> 
> Simon

Re: [PATCH v3] inferior without argument prints detail of current inferior

[Simon Marchi via Gdb-patches]

On 2021-01-10 12:37 p.m., Lancelot SIX wrote:
> No, I do not, nor do I have an account on sourceware.org. Given that
> I’ll try to continue to contribute (to the extend of what my spare time
> allows me to), I guess this would make sence!  Should I follow the
> procedure describe in https://sourceware.org/cgi-bin/pdw/ps_form.cgi and
> provide your email as reference?

Yes!

Simon

Re: [PATCH v3] inferior without argument prints detail of current inferior

[Eli Zaretskii via Gdb-patches]

> Date: Sat,  9 Jan 2021 21:24:16 +0000
> From: Lancelot SIX via Gdb-patches <gdb-patches@sourceware.org>
> Cc: Lancelot SIX <lsix@lancelotsix.com>
> 
> Changes from V1:
>   * Add test.
> 
> Change from V2:
>   * Fix gdb/doc/ChangeLog entry.
>   * My copyright assignment has been signed.
> 
> gdb/doc/ChangeLog:
> 
> 	* gdb.texinfo (Inferiors Connections and Programs): Document the
> 	inferior command when used without argument.
> 
> gdb/ChangeLog:
> 
> 	* inferior.c (inferior_command): When no argument is given to the
> 	inferior command, display info about the currently selected
> 	inferior.
> 
> gdb/testsuite/ChangeLog:
> 
> 	* gdb.base/inferior-noarg.c: New test.
> 	* gdb.base/inferior-noarg.exp: New test.

OK for the documentation part, but does this warrant a NEWS entry as
well?

Thanks.

Re: [PATCH v3] inferior without argument prints detail of current inferior

[Lancelot SIX via Gdb-patches]

On Sun, Jan 10, 2021 at 06:41:04PM +0200, Eli Zaretskii wrote:
> > Date: Sat,  9 Jan 2021 21:24:16 +0000
> > From: Lancelot SIX via Gdb-patches <gdb-patches@sourceware.org>
> > Cc: Lancelot SIX <lsix@lancelotsix.com>
> > 
> > Changes from V1:
> >   * Add test.
> > 
> > Change from V2:
> >   * Fix gdb/doc/ChangeLog entry.
> >   * My copyright assignment has been signed.
> > 
> > gdb/doc/ChangeLog:
> > 
> > 	* gdb.texinfo (Inferiors Connections and Programs): Document the
> > 	inferior command when used without argument.
> > 
> > gdb/ChangeLog:
> > 
> > 	* inferior.c (inferior_command): When no argument is given to the
> > 	inferior command, display info about the currently selected
> > 	inferior.
> > 
> > gdb/testsuite/ChangeLog:
> > 
> > 	* gdb.base/inferior-noarg.c: New test.
> > 	* gdb.base/inferior-noarg.exp: New test.
> 
> OK for the documentation part, but does this warrant a NEWS entry as
> well?
> 
> Thanks.

I’ll add an entry in the next submission.

Lancelot.

[PATCH v4] inferior without argument prints detail of current inferior

[Lancelot SIX via Gdb-patches]

This patch makes the inferior command display information about the
current inferior when called with no argument. This behavior is similar
to the one of the thread command.

This contribution is inspired by an item in
https://sourceware.org/gdb/wiki/ProjectIdeas

Before patch:

    (gdb) info inferior
      Num  Description       Connection           Executable
    * 1    process 19221     1 (native)           /home/lsix/tmp/a.out
      2    process 19239     1 (native)           /home/lsix/tmp/a.out
    (gdb) inferior 2
    [Switching to inferior 2 [process 19239] (/home/lsix/tmp/a.out)]
    [Switching to thread 2.1 (process 19239)]
    #0  0x0000000000401146 in main ()
    (gdb) inferior
    Argument required (expression to compute).

After patch:

    (gdb) info inferior
      Num  Description       Connection           Executable
    * 1    process 18699     1 (native)           /home/lsix/tmp/a.out
      2    process 18705     1 (native)           /home/lsix/tmp/a.out
    (gdb) inferior 2
    [Switching to inferior 2 [process 18705] (/home/lsix/tmp/a.out)]
    [Switching to thread 2.1 (process 18705)]
    #0  0x0000000000401146 in main ()
    (gdb) inferior
    [Current inferior is 2 [process 18705] (/home/lsix/tmp/a.out)]

Changes from V1:
	* Add test.

Change from V2:
	* Fix gdb/doc/ChangeLog entry.

Change from V3:
	* Add entry in the NEWS file.
	* Improve inferior-noarg.expr and remove assumptions particular
	format in pid_to_str.
	* Fix copyright year in new files.

gdb/doc/ChangeLog:

	* gdb.texinfo (Inferiors Connections and Programs): Document the
	inferior command when used without argument.

gdb/ChangeLog:

  * NEWS: Add entry for the behavior change of the inferior command.
	* inferior.c (inferior_command): When no argument is given to the
	inferior command, display info about the currently selected
	inferior.

gdb/testsuite/ChangeLog:

	* gdb.base/inferior-noarg.c: New test.
	* gdb.base/inferior-noarg.exp: New test.

---
---
 gdb/NEWS                                  |  6 +++
 gdb/doc/gdb.texinfo                       | 16 +++++++
 gdb/inferior.c                            | 58 +++++++++++++++--------
 gdb/testsuite/gdb.base/inferior-noarg.c   | 22 +++++++++
 gdb/testsuite/gdb.base/inferior-noarg.exp | 36 ++++++++++++++
 5 files changed, 117 insertions(+), 21 deletions(-)
 create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.c
 create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.exp

diff --git a/gdb/NEWS b/gdb/NEWS
index 66702862ef..d9788f6733 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -75,6 +75,12 @@ maintenance flush-symbol-cache
   'maintenance flush register-cache' and 'maintenance flush
   symbol-cache' respectively.
 
+inferior [ID]
+  When the ID parameter is omitted, then this command prints information
+  about the current inferior.  When the ID parameter is present, the
+  behavior of the command is unchanged and have the inferior ID become
+  the current inferior.
+
 *** Changes in GDB 10
 
 * There are new feature names for ARC targets: "org.gnu.gdb.arc.core"
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 69fa6b709b..a97a342e9d 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -3202,6 +3202,22 @@ For example,
   2    process 2307      2 (extended-remote host:10000)  hello
 @end smallexample
 
+To get informations about the current inferior, use @code{inferior}:
+
+@table @code
+@kindex inferior
+@item inferior
+Shows information about the current inferior.
+
+For example,
+@end table
+@c end table here to get a little more width for example
+
+@smallexample
+(@value{GDBP}) inferior
+[Current inferior is 1 [process 3401] (helloworld)]
+@end smallexample
+
 To find out what open target connections exist at any moment, use
 @w{@code{info connections}}:
 
diff --git a/gdb/inferior.c b/gdb/inferior.c
index 3ff0512c38..49f869a4c7 100644
--- a/gdb/inferior.c
+++ b/gdb/inferior.c
@@ -635,34 +635,50 @@ inferior_command (const char *args, int from_tty)
   struct inferior *inf;
   int num;
 
-  num = parse_and_eval_long (args);
-
-  inf = find_inferior_id (num);
-  if (inf == NULL)
-    error (_("Inferior ID %d not known."), num);
-
-  if (inf->pid != 0)
+  if (args == nullptr)
     {
-      if (inf != current_inferior ())
-	{
-	  thread_info *tp = any_thread_of_inferior (inf);
-	  if (tp == NULL)
-	    error (_("Inferior has no threads."));
+      inf = current_inferior ();
+      gdb_assert (inf != nullptr);
+      const char *filename = inf->pspace->exec_filename.get ();
 
-	  switch_to_thread (tp);
-	}
+      if (filename == nullptr)
+	filename = _("<noexec>");
 
-      gdb::observers::user_selected_context_changed.notify
-	(USER_SELECTED_INFERIOR
-	 | USER_SELECTED_THREAD
-	 | USER_SELECTED_FRAME);
+      printf_filtered (_("[Current inferior is %d [%s] (%s)]\n"),
+		       inf->num, inferior_pid_to_str (inf->pid).c_str (),
+		       filename);
     }
   else
     {
-      switch_to_inferior_no_thread (inf);
+      num = parse_and_eval_long (args);
+
+      inf = find_inferior_id (num);
+      if (inf == NULL)
+	error (_("Inferior ID %d not known."), num);
+
+      if (inf->pid != 0)
+	{
+	  if (inf != current_inferior ())
+	    {
+	      thread_info *tp = any_thread_of_inferior (inf);
+	      if (tp == NULL)
+		error (_("Inferior has no threads."));
 
-      gdb::observers::user_selected_context_changed.notify
-	(USER_SELECTED_INFERIOR);
+	      switch_to_thread (tp);
+	    }
+
+	  gdb::observers::user_selected_context_changed.notify
+	    (USER_SELECTED_INFERIOR
+	     | USER_SELECTED_THREAD
+	     | USER_SELECTED_FRAME);
+	}
+      else
+	{
+	  switch_to_inferior_no_thread (inf);
+
+	  gdb::observers::user_selected_context_changed.notify
+	    (USER_SELECTED_INFERIOR);
+	}
     }
 }
 
diff --git a/gdb/testsuite/gdb.base/inferior-noarg.c b/gdb/testsuite/gdb.base/inferior-noarg.c
new file mode 100644
index 0000000000..bfe52c018d
--- /dev/null
+++ b/gdb/testsuite/gdb.base/inferior-noarg.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2021 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/>.  */
+
+int
+main (void)
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/inferior-noarg.exp b/gdb/testsuite/gdb.base/inferior-noarg.exp
new file mode 100644
index 0000000000..65d23fe46e
--- /dev/null
+++ b/gdb/testsuite/gdb.base/inferior-noarg.exp
@@ -0,0 +1,36 @@
+# Copyright 2021 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/>.
+
+# This test case checks that the 'inferior' command, when given no
+# argument, displays information about the inferior currently active.
+
+standard_testfile
+
+if { [prepare_for_testing "failed to prepare" \
+	${testfile} ${srcfile}] } {
+    return
+}
+
+gdb_test "inferior" "\[Current inferior is 1 \[<null>\] (.*)\]" "inferior not running"
+
+if { ![runto_main] } {
+    untested "could not run to main"
+    return
+}
+
+gdb_test "inferior" {\[Current inferior is 1 \[.*\] (.*)\]} "inferior running"
+gdb_test "clone-inferior" "Added inferior 2.*" "create new inferior"
+gdb_test "inferior 2" "\[Switching to inferior 2 \[<null>\] (.*)]" "change inferior"
+gdb_test "inferior" "\[Current inferior is 2 \[<null>\] (.*)\]" "show new inferior"
-- 
2.29.2

Re: [PATCH v4] inferior without argument prints detail of current inferior

[Simon Marchi via Gdb-patches]

On 2021-01-10 12:58 p.m., Lancelot SIX via Gdb-patches wrote:
> This patch makes the inferior command display information about the
> current inferior when called with no argument. This behavior is similar
> to the one of the thread command.
> 
> This contribution is inspired by an item in
> https://sourceware.org/gdb/wiki/ProjectIdeas
> 
> Before patch:
> 
>     (gdb) info inferior
>       Num  Description       Connection           Executable
>     * 1    process 19221     1 (native)           /home/lsix/tmp/a.out
>       2    process 19239     1 (native)           /home/lsix/tmp/a.out
>     (gdb) inferior 2
>     [Switching to inferior 2 [process 19239] (/home/lsix/tmp/a.out)]
>     [Switching to thread 2.1 (process 19239)]
>     #0  0x0000000000401146 in main ()
>     (gdb) inferior
>     Argument required (expression to compute).
> 
> After patch:
> 
>     (gdb) info inferior
>       Num  Description       Connection           Executable
>     * 1    process 18699     1 (native)           /home/lsix/tmp/a.out
>       2    process 18705     1 (native)           /home/lsix/tmp/a.out
>     (gdb) inferior 2
>     [Switching to inferior 2 [process 18705] (/home/lsix/tmp/a.out)]
>     [Switching to thread 2.1 (process 18705)]
>     #0  0x0000000000401146 in main ()
>     (gdb) inferior
>     [Current inferior is 2 [process 18705] (/home/lsix/tmp/a.out)]
> 
> Changes from V1:
> 	* Add test.
> 
> Change from V2:
> 	* Fix gdb/doc/ChangeLog entry.
> 
> Change from V3:
> 	* Add entry in the NEWS file.
> 	* Improve inferior-noarg.expr and remove assumptions particular
> 	format in pid_to_str.
> 	* Fix copyright year in new files.
> 
> gdb/doc/ChangeLog:
> 
> 	* gdb.texinfo (Inferiors Connections and Programs): Document the
> 	inferior command when used without argument.
> 
> gdb/ChangeLog:
> 
>   * NEWS: Add entry for the behavior change of the inferior command.
> 	* inferior.c (inferior_command): When no argument is given to the
> 	inferior command, display info about the currently selected
> 	inferior.
> 
> gdb/testsuite/ChangeLog:
> 
> 	* gdb.base/inferior-noarg.c: New test.
> 	* gdb.base/inferior-noarg.exp: New test.
> 
> ---
> ---
>  gdb/NEWS                                  |  6 +++
>  gdb/doc/gdb.texinfo                       | 16 +++++++
>  gdb/inferior.c                            | 58 +++++++++++++++--------
>  gdb/testsuite/gdb.base/inferior-noarg.c   | 22 +++++++++
>  gdb/testsuite/gdb.base/inferior-noarg.exp | 36 ++++++++++++++
>  5 files changed, 117 insertions(+), 21 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.c
>  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.exp
> 
> diff --git a/gdb/NEWS b/gdb/NEWS
> index 66702862ef..d9788f6733 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -75,6 +75,12 @@ maintenance flush-symbol-cache
>    'maintenance flush register-cache' and 'maintenance flush
>    symbol-cache' respectively.
>  
> +inferior [ID]
> +  When the ID parameter is omitted, then this command prints information
> +  about the current inferior.  When the ID parameter is present, the
> +  behavior of the command is unchanged and have the inferior ID become
> +  the current inferior.

I'll let Eli review the NEWS entry, otherwise the patch LGTM.  Let us know
when you have your sourceware account.

Simon

Re: [PATCH v4] inferior without argument prints detail of current inferior

[Eli Zaretskii via Gdb-patches]

> Date: Sun, 10 Jan 2021 20:14:22 -0500
> From: Simon Marchi via Gdb-patches <gdb-patches@sourceware.org>
> 
> > +inferior [ID]
> > +  When the ID parameter is omitted, then this command prints information
> > +  about the current inferior.  When the ID parameter is present, the
> > +  behavior of the command is unchanged and have the inferior ID become
> > +  the current inferior.
> 
> I'll let Eli review the NEWS entry

The NEWS entry is OK, thanks.

Re: [PATCH v4] inferior without argument prints detail of current inferior

[Lancelot SIX via Gdb-patches]

Hi,

I have pushed this patch.

I’d like to update https://sourceware.org/gdb/wiki/ProjectIdeas.  To do
so, I need to be in the EditorGroup.  Can a member of the group update
the page or grant me access?

Thanks,
Lancelot.

Le Sun, Jan 10, 2021 at 05:58:24PM +0000, Lancelot SIX a écrit :
> This patch makes the inferior command display information about the
> current inferior when called with no argument. This behavior is similar
> to the one of the thread command.
> 
> This contribution is inspired by an item in
> https://sourceware.org/gdb/wiki/ProjectIdeas
> 
> Before patch:
> 
>     (gdb) info inferior
>       Num  Description       Connection           Executable
>     * 1    process 19221     1 (native)           /home/lsix/tmp/a.out
>       2    process 19239     1 (native)           /home/lsix/tmp/a.out
>     (gdb) inferior 2
>     [Switching to inferior 2 [process 19239] (/home/lsix/tmp/a.out)]
>     [Switching to thread 2.1 (process 19239)]
>     #0  0x0000000000401146 in main ()
>     (gdb) inferior
>     Argument required (expression to compute).
> 
> After patch:
> 
>     (gdb) info inferior
>       Num  Description       Connection           Executable
>     * 1    process 18699     1 (native)           /home/lsix/tmp/a.out
>       2    process 18705     1 (native)           /home/lsix/tmp/a.out
>     (gdb) inferior 2
>     [Switching to inferior 2 [process 18705] (/home/lsix/tmp/a.out)]
>     [Switching to thread 2.1 (process 18705)]
>     #0  0x0000000000401146 in main ()
>     (gdb) inferior
>     [Current inferior is 2 [process 18705] (/home/lsix/tmp/a.out)]
> 
> Changes from V1:
> 	* Add test.
> 
> Change from V2:
> 	* Fix gdb/doc/ChangeLog entry.
> 
> Change from V3:
> 	* Add entry in the NEWS file.
> 	* Improve inferior-noarg.expr and remove assumptions particular
> 	format in pid_to_str.
> 	* Fix copyright year in new files.
> 
> gdb/doc/ChangeLog:
> 
> 	* gdb.texinfo (Inferiors Connections and Programs): Document the
> 	inferior command when used without argument.
> 
> gdb/ChangeLog:
> 
>   * NEWS: Add entry for the behavior change of the inferior command.
> 	* inferior.c (inferior_command): When no argument is given to the
> 	inferior command, display info about the currently selected
> 	inferior.
> 
> gdb/testsuite/ChangeLog:
> 
> 	* gdb.base/inferior-noarg.c: New test.
> 	* gdb.base/inferior-noarg.exp: New test.
> 
> ---
> ---
>  gdb/NEWS                                  |  6 +++
>  gdb/doc/gdb.texinfo                       | 16 +++++++
>  gdb/inferior.c                            | 58 +++++++++++++++--------
>  gdb/testsuite/gdb.base/inferior-noarg.c   | 22 +++++++++
>  gdb/testsuite/gdb.base/inferior-noarg.exp | 36 ++++++++++++++
>  5 files changed, 117 insertions(+), 21 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.c
>  create mode 100644 gdb/testsuite/gdb.base/inferior-noarg.exp
> 
> diff --git a/gdb/NEWS b/gdb/NEWS
> index 66702862ef..d9788f6733 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -75,6 +75,12 @@ maintenance flush-symbol-cache
>    'maintenance flush register-cache' and 'maintenance flush
>    symbol-cache' respectively.
>  
> +inferior [ID]
> +  When the ID parameter is omitted, then this command prints information
> +  about the current inferior.  When the ID parameter is present, the
> +  behavior of the command is unchanged and have the inferior ID become
> +  the current inferior.
> +
>  *** Changes in GDB 10
>  
>  * There are new feature names for ARC targets: "org.gnu.gdb.arc.core"
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 69fa6b709b..a97a342e9d 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -3202,6 +3202,22 @@ For example,
>    2    process 2307      2 (extended-remote host:10000)  hello
>  @end smallexample
>  
> +To get informations about the current inferior, use @code{inferior}:
> +
> +@table @code
> +@kindex inferior
> +@item inferior
> +Shows information about the current inferior.
> +
> +For example,
> +@end table
> +@c end table here to get a little more width for example
> +
> +@smallexample
> +(@value{GDBP}) inferior
> +[Current inferior is 1 [process 3401] (helloworld)]
> +@end smallexample
> +
>  To find out what open target connections exist at any moment, use
>  @w{@code{info connections}}:
>  
> diff --git a/gdb/inferior.c b/gdb/inferior.c
> index 3ff0512c38..49f869a4c7 100644
> --- a/gdb/inferior.c
> +++ b/gdb/inferior.c
> @@ -635,34 +635,50 @@ inferior_command (const char *args, int from_tty)
>    struct inferior *inf;
>    int num;
>  
> -  num = parse_and_eval_long (args);
> -
> -  inf = find_inferior_id (num);
> -  if (inf == NULL)
> -    error (_("Inferior ID %d not known."), num);
> -
> -  if (inf->pid != 0)
> +  if (args == nullptr)
>      {
> -      if (inf != current_inferior ())
> -	{
> -	  thread_info *tp = any_thread_of_inferior (inf);
> -	  if (tp == NULL)
> -	    error (_("Inferior has no threads."));
> +      inf = current_inferior ();
> +      gdb_assert (inf != nullptr);
> +      const char *filename = inf->pspace->exec_filename.get ();
>  
> -	  switch_to_thread (tp);
> -	}
> +      if (filename == nullptr)
> +	filename = _("<noexec>");
>  
> -      gdb::observers::user_selected_context_changed.notify
> -	(USER_SELECTED_INFERIOR
> -	 | USER_SELECTED_THREAD
> -	 | USER_SELECTED_FRAME);
> +      printf_filtered (_("[Current inferior is %d [%s] (%s)]\n"),
> +		       inf->num, inferior_pid_to_str (inf->pid).c_str (),
> +		       filename);
>      }
>    else
>      {
> -      switch_to_inferior_no_thread (inf);
> +      num = parse_and_eval_long (args);
> +
> +      inf = find_inferior_id (num);
> +      if (inf == NULL)
> +	error (_("Inferior ID %d not known."), num);
> +
> +      if (inf->pid != 0)
> +	{
> +	  if (inf != current_inferior ())
> +	    {
> +	      thread_info *tp = any_thread_of_inferior (inf);
> +	      if (tp == NULL)
> +		error (_("Inferior has no threads."));
>  
> -      gdb::observers::user_selected_context_changed.notify
> -	(USER_SELECTED_INFERIOR);
> +	      switch_to_thread (tp);
> +	    }
> +
> +	  gdb::observers::user_selected_context_changed.notify
> +	    (USER_SELECTED_INFERIOR
> +	     | USER_SELECTED_THREAD
> +	     | USER_SELECTED_FRAME);
> +	}
> +      else
> +	{
> +	  switch_to_inferior_no_thread (inf);
> +
> +	  gdb::observers::user_selected_context_changed.notify
> +	    (USER_SELECTED_INFERIOR);
> +	}
>      }
>  }
>  
> diff --git a/gdb/testsuite/gdb.base/inferior-noarg.c b/gdb/testsuite/gdb.base/inferior-noarg.c
> new file mode 100644
> index 0000000000..bfe52c018d
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/inferior-noarg.c
> @@ -0,0 +1,22 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2021 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/>.  */
> +
> +int
> +main (void)
> +{
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.base/inferior-noarg.exp b/gdb/testsuite/gdb.base/inferior-noarg.exp
> new file mode 100644
> index 0000000000..65d23fe46e
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/inferior-noarg.exp
> @@ -0,0 +1,36 @@
> +# Copyright 2021 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/>.
> +
> +# This test case checks that the 'inferior' command, when given no
> +# argument, displays information about the inferior currently active.
> +
> +standard_testfile
> +
> +if { [prepare_for_testing "failed to prepare" \
> +	${testfile} ${srcfile}] } {
> +    return
> +}
> +
> +gdb_test "inferior" "\[Current inferior is 1 \[<null>\] (.*)\]" "inferior not running"
> +
> +if { ![runto_main] } {
> +    untested "could not run to main"
> +    return
> +}
> +
> +gdb_test "inferior" {\[Current inferior is 1 \[.*\] (.*)\]} "inferior running"
> +gdb_test "clone-inferior" "Added inferior 2.*" "create new inferior"
> +gdb_test "inferior 2" "\[Switching to inferior 2 \[<null>\] (.*)]" "change inferior"
> +gdb_test "inferior" "\[Current inferior is 2 \[<null>\] (.*)\]" "show new inferior"
> -- 
> 2.29.2
> 

-- 
Lancelot SIX

Re: [PATCH v4] inferior without argument prints detail of current inferior

[Simon Marchi via Gdb-patches]

On 2021-02-02 5:44 p.m., Lancelot SIX via Gdb-patches wrote:
> Hi,
> 
> I have pushed this patch.
> 
> I’d like to update https://sourceware.org/gdb/wiki/ProjectIdeas.  To do
> so, I need to be in the EditorGroup.  Can a member of the group update
> the page or grant me access?
> 
> Thanks,
> Lancelot.

What's your username?

Simon

Re: [PATCH v4] inferior without argument prints detail of current inferior

[Lancelot SIX via Gdb-patches]

> What's your username?
> 
> Simon

Sorry I forgot to mention it.

It is 'LancelotSix'.

Lancelot.

Re: [PATCH v4] inferior without argument prints detail of current inferior

[Simon Marchi via Gdb-patches]

On 2021-02-02 6:04 p.m., Lancelot SIX wrote:
>> What's your username?
>>
>> Simon
> 
> Sorry I forgot to mention it.
> 
> It is 'LancelotSix'.
> 
> Lancelot.
> 

Done!

Simon