Re: [PATCH v3 1/7] Add a new $_inferior convenience variable

Simon Marchi
2016-01-06T18:56:41Z

On 16-01-06 08:03 AM, Pedro Alves wrote:
> Like $_thread, but holds the current inferior number.
>
> gdb/ChangeLog:
> 2016-01-06 Pedro Alves <palves@redhat.com>
>
> * NEWS: Mention $_inferior.
> * inferior.c (inferior_id_make_value): New.
> (inferior_funcs): New.
> (_initialize_inferior): Create $_inferior variable.
>
> gdb/testsuite/ChangeLog:
> 2016-01-06 Pedro Alves <palves@redhat.com>
>
> * gdb.base/default.exp: Expect $_inferior as well.
> * gdb.multi/base.exp: Test $_inferior.
>
> gdb/doc/ChangeLog:
> 2016-01-06 Pedro Alves <palves@redhat.com>
>
> * gdb.texinfo (Inferiors and Programs): Document the $_inferior
> convenience variable.
> (Convenience Vars): Likewise.
> ---
> gdb/NEWS | 3 +++
> gdb/doc/gdb.texinfo | 10 ++++++++++
> gdb/inferior.c | 21 +++++++++++++++++++++
> gdb/testsuite/gdb.base/default.exp | 1 +
> gdb/testsuite/gdb.multi/base.exp | 4 ++++
> 5 files changed, 39 insertions(+)
>
> diff --git a/gdb/NEWS b/gdb/NEWS
> index 484d98d..31c870d 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -3,6 +3,9 @@
>
> *** Changes since GDB 7.10
>
> +* The new convenience variable $_inferior holds the number of the
> + current inferior.
> +
> * Record btrace now supports non-stop mode.
>
> * Support for tracepoints on aarch64-linux was added in GDBserver.
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 0778383..f01b703 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -2658,6 +2658,12 @@ Make inferior number @var{infno} the current inferior. The argument
> in the first field of the @samp{info inferiors} display.
> @end table
>
> +@vindex $_inferior@r{, convenience variable}
> +The debugger convenience variable @samp{$_inferior} contains the
> +number of the current inferior. You may find this useful in writing
> +breakpoint conditional expressions, command scripts, and so forth.
> +@xref{Convenience Vars,, Convenience Variables}, for general
> +information on convenience variables.
>
> You can get multiple executables into a debugging session via the
> @code{add-inferior} and @w{@code{clone-inferior}} commands. On some
> @@ -10382,6 +10388,10 @@ gdbserver that supports the @code{qGetTIBAddr} request.
> @xref{General Query Packets}.
> This variable contains the address of the thread information block.
>
> +@item $_inferior
> +The number of the current inferior. @xref{Inferiors and
> +Programs, ,Debugging Multiple Inferiors and Programs}.
> +
> @end table
>
> @node Convenience Funs
> diff --git a/gdb/inferior.c b/gdb/inferior.c
> index e71104d..8f9ac33 100644
> --- a/gdb/inferior.c
> +++ b/gdb/inferior.c
> @@ -1008,6 +1008,26 @@ show_print_inferior_events (struct ui_file *file, int from_tty,
> fprintf_filtered (file, _("Printing of inferior events is %s.\n"), value);
> }
>
> +/* Return a new value for the selected inferior's id. */
> +
> +static struct value *
> +inferior_id_make_value (struct gdbarch *gdbarch, struct internalvar *var,
> + void *ignore)
> +{
> + struct inferior *inf = current_inferior ();
> +
> + return value_from_longest (builtin_type (gdbarch)->builtin_int, inf->num);
> +}
> +
> +/* Implementation of `$_inferior' variable. */
> +
> +static const struct internalvar_funcs inferior_funcs =
> +{
> + inferior_id_make_value,
> + NULL,
> + NULL
> +};
> +
> \f
>
> void
> @@ -1071,4 +1091,5 @@ Show printing of inferior events (e.g., inferior start and exit)."), NULL,
> show_print_inferior_events,
> &setprintlist, &showprintlist);
>
> + create_internalvar_type_lazy ("_inferior", &inferior_funcs, NULL);
> }
> diff --git a/gdb/testsuite/gdb.base/default.exp b/gdb/testsuite/gdb.base/default.exp
> index 90bf27d..fec2cde 100644
> --- a/gdb/testsuite/gdb.base/default.exp
> +++ b/gdb/testsuite/gdb.base/default.exp
> @@ -587,6 +587,7 @@ set show_conv_list \
> {$_sdata = void} \
> {$_siginfo = void} \
> {$_thread = 0} \
> + {$_inferior = 1} \
> {$_exception = <error: No frame selected>} \
> {$_probe_argc = <error: No frame selected>} \
> {$_probe_arg0 = <error: No frame selected>} \
> diff --git a/gdb/testsuite/gdb.multi/base.exp b/gdb/testsuite/gdb.multi/base.exp
> index 6f0bc63..1aa907d 100644
> --- a/gdb/testsuite/gdb.multi/base.exp
> +++ b/gdb/testsuite/gdb.multi/base.exp
> @@ -44,12 +44,16 @@ if { [build_executable ${testfile}.exp ${exec3} "${srcfile3}" {debug}] == -1 } {
>
> clean_restart ${exec1}
>
> +gdb_test {print $_inferior} " = 1"
> +
> # Add an empty inferior, switch to it, and load a main executable into
> # it.
> gdb_test "add-inferior" "Added inferior 2.*" "add empty inferior 2"
> gdb_test "inferior 2" "Switching to inferior 2.*" "switch to inferior 2"
> gdb_test "file ${binfile2}" ".*" "load ${exec2} file in inferior 2"
>
> +gdb_test {print $_inferior} " = 2" "print \$_inferior after switching"
> +
> # Add a new inferior and load a main executable into it in one
> # command.
> gdb_test "add-inferior -exec ${binfile3}" \
>

LGTM.