[Patch] add implementation of stack-info-frame MI command

[Patch] add implementation of stack-info-frame MI command

[Mo DeJong]

Hello.

While using the MI, I noticed that there is a real problem trying to find
the current stack level. One could get the stack and look at the level
value of the first frame or parse the results of a cli frame command,
but these both seem ugly. What is needed is a stack-info-frame that
returns the current stack level to complement the stack-select-frame
which selects a stack level.

Here is what I propose:

-stack-info-frame
^done,level="0"
(gdb)
-stack-select-frame 5
^done
(gdb)
-stack-info-frame
^done,level="5"
(gdb)

The stack-info-frame command is currently unimplemented
even though it appears in the documentation, so there is
no way this patch could break anything. The only objection
I could think of was that folks might want the command
to return all the info about the current frame, like the
stack-list-frames method. That is actually not needed since
one could always run stack-list-frames and then select
a stack level out of the returned frames. In real code,
it is better to query the whole stack as opposed to changing
the stack, doing a query of the current frame, changing the
stack, then doing a query, and so on.

I forgot to mention in my last patch that I sent in my FSF
copyright paperwork, so that should not stand in the way
of incorporating my patches any longer.

cheers
Mo

2002-07-25  Mo DeJong  <supermo@bayarea.net>

	* mi-stack.exp: Add test for stack-info-frame
	command that returns the current stack level.

Index: mi-stack.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.mi/mi-stack.exp,v
retrieving revision 1.8
diff -u -r1.8 mi-stack.exp
--- mi-stack.exp	19 Aug 2001 01:23:43 -0000	1.8
+++ mi-stack.exp	25 Jul 2002 21:06:38 -0000
@@ -192,6 +192,10 @@
 	    "232\\^done" \
                 "stack select frame 1"
 
+    mi_gdb_test "232-stack-info-frame" \
+	    "232\\^done,level=\"1\"" \
+                "stack info frame"
+
     mi_gdb_test "232-stack-list-locals 1" \
 	    "232\\^done,locals=\\\[\\\]" \
                 "stack locals listing for new frame"


2002-07-25  Mo DeJong  <supermo@bayarea.net>

	* gdbmi.texinfo (stack-info-frame): Document
	return of current stack level by stack-info-frame.
	* mi-cmd-stack.c (mi_cmd_stack_info_frame):
	Implement stack-info-frame command.
	* mi-cmds.c: Add mi_cmd_stack_info_frame to
	mi command lookup table.
	* mi-cmds.h: Add mi_cmd_stack_info_frame decl.

Index: gdbmi.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/mi/gdbmi.texinfo,v
retrieving revision 1.26
diff -u -r1.26 gdbmi.texinfo
--- gdbmi.texinfo	25 Feb 2002 02:13:09 -0000	1.26
+++ gdbmi.texinfo	25 Jul 2002 21:11:34 -0000
@@ -2558,12 +2558,18 @@
  -stack-info-frame
 @end example
 
-Get info on the current frame.
+Get the stack level of the current frame.
+
+@smallexample
+(@value{GDBP})
+-stack-info-frame
+^done,level="0"
+(@value{GDBP})
+@end smallexample
 
 @subsubheading @value{GDBN} Command
 
-The corresponding @value{GDBN} command is @samp{info frame} or @samp{frame}
-(without arguments).
+There's no equivalent @value{GDBN} command.
 
 @subsubheading Example
 N.A.
Index: mi-cmd-stack.c
===================================================================
RCS file: /cvs/src/src/gdb/mi/mi-cmd-stack.c,v
retrieving revision 1.10
diff -u -r1.10 mi-cmd-stack.c
--- mi-cmd-stack.c	5 Feb 2002 19:28:36 -0000	1.10
+++ mi-cmd-stack.c	25 Jul 2002 21:11:35 -0000
@@ -307,3 +307,16 @@
     select_frame_command_wrapper (argv[0], 1 /* not used */ );
   return MI_CMD_DONE;
 }
+
+enum mi_cmd_result
+mi_cmd_stack_info_frame (char *command, char **argv, int argc)
+{
+  if (!target_has_stack)
+    error ("mi_cmd_stack_info_frame: No stack.");
+
+  if (argc > 0)
+    error ("mi_cmd_stack_info_frame: Command accepts no arguments");
+
+  ui_out_field_fmt (uiout, "level", "%d", selected_frame_level);
+  return MI_CMD_DONE;
+}
Index: mi-cmds.c
===================================================================
RCS file: /cvs/src/src/gdb/mi/mi-cmds.c,v
retrieving revision 1.8
diff -u -r1.8 mi-cmds.c
--- mi-cmds.c	6 Mar 2001 08:21:45 -0000	1.8
+++ mi-cmds.c	25 Jul 2002 21:11:35 -0000
@@ -103,7 +103,7 @@
   {"signal-list-handle-actions", 0, 0},
   {"signal-list-signal-types", 0, 0},
   {"stack-info-depth", 0, 0, mi_cmd_stack_info_depth},
-  {"stack-info-frame", 0, 0},
+  {"stack-info-frame", 0, 0, mi_cmd_stack_info_frame},
   {"stack-list-arguments", 0, 0, mi_cmd_stack_list_args},
   {"stack-list-exception-handlers", 0, 0},
   {"stack-list-frames", 0, 0, mi_cmd_stack_list_frames},
Index: mi-cmds.h
===================================================================
RCS file: /cvs/src/src/gdb/mi/mi-cmds.h,v
retrieving revision 1.5
diff -u -r1.5 mi-cmds.h
--- mi-cmds.h	6 Mar 2001 08:21:45 -0000	1.5
+++ mi-cmds.h	25 Jul 2002 21:11:35 -0000
@@ -76,6 +76,7 @@
 extern mi_cmd_args_ftype mi_cmd_exec_interrupt;
 extern mi_cmd_argv_ftype mi_cmd_gdb_exit;
 extern mi_cmd_argv_ftype mi_cmd_stack_info_depth;
+extern mi_cmd_argv_ftype mi_cmd_stack_info_frame;
 extern mi_cmd_argv_ftype mi_cmd_stack_list_args;
 extern mi_cmd_argv_ftype mi_cmd_stack_list_frames;
 extern mi_cmd_argv_ftype mi_cmd_stack_list_locals;

Re: [Patch] add implementation of stack-info-frame MI command

[Andrew Cagney]

See my post to GDB@.  I think this should be handled as an event and not 
as a command.

The user entering a command like ``up'' needs to trigger the event 
notification anyway.

enjoy,
Andrew


> While using the MI, I noticed that there is a real problem trying to find
> the current stack level. One could get the stack and look at the level
> value of the first frame or parse the results of a cli frame command,
> but these both seem ugly. What is needed is a stack-info-frame that
> returns the current stack level to complement the stack-select-frame
> which selects a stack level.
> 
> Here is what I propose:
> 
> -stack-info-frame
> ^done,level="0"
> (gdb)
> -stack-select-frame 5
> ^done
> (gdb)
> -stack-info-frame
> ^done,level="5"
> (gdb)
> 
> The stack-info-frame command is currently unimplemented
> even though it appears in the documentation, so there is
> no way this patch could break anything. The only objection
> I could think of was that folks might want the command
> to return all the info about the current frame, like the
> stack-list-frames method. That is actually not needed since
> one could always run stack-list-frames and then select
> a stack level out of the returned frames. In real code,
> it is better to query the whole stack as opposed to changing
> the stack, doing a query of the current frame, changing the
> stack, then doing a query, and so on.
> 
> I forgot to mention in my last patch that I sent in my FSF
> copyright paperwork, so that should not stand in the way
> of incorporating my patches any longer.
> 
> cheers
> Mo

Re: [Patch] add implementation of stack-info-frame MI command

[Keith Seitz]

On Thu, 25 Jul 2002, Andrew Cagney wrote:

> See my post to GDB@.  I think this should be handled as an event and not
> as a command.

As Mo has implemented, -stack-info-frame would return the very same
information as -stack-info-depth. I always thought that -stack-info-frame
would give information about the current (or given) frame, i.e., saved pc,
saved registers, etc.

> The user entering a command like ``up'' needs to trigger the event
> notification anyway.

As for "up"/"down"/"frame" commands to the console, I have already
implemented a notification event on the "mi branch".

Keith

Re: [Patch] add implementation of stack-info-frame MI command

[Mo DeJong]

On Thu, 25 Jul 2002 17:03:57 -0700 (PDT)
Keith Seitz <keiths@redhat.com> wrote:

> On Thu, 25 Jul 2002, Andrew Cagney wrote:
> 
> > See my post to GDB.  I think this should be handled as an event and not
> > as a command.
> 
> As Mo has implemented, -stack-info-frame would return the very same
> information as -stack-info-depth.

It would? I was under the impression that -stack-info-depth would return
the number of frames on the stack without taking what the current frame
is into account.

-stack-info-depth
^done,depth="3"
(gdb) 
^done depth 3

-stack-info-frame
^done,level="0"
(gdb) 
^done level 0

up
^done,frame={level="1 ",addr="0x080484a8",func="main",args=[{name="argc",value="1"},{name="argv",value="0xbffff5c4"}],file="resources.c",line="38"},line="38",file="resources.c"

-stack-info-depth
^done,depth="3"
(gdb) 

-stack-info-frame
^done,level="1"
(gdb) 


> I always thought that -stack-info-frame
> would give information about the current (or given) frame, i.e., saved pc,
> saved registers, etc.

I can't speak as to the original design goals. The existing documentation
for the command is not very clear about what it should do. I just
thought -stack-info-frame would work like -stack-select-frame in
that it would deal with an integer stack level. How is one meant to
query the stack level?

Mo

Re: [Patch] add implementation of stack-info-frame MI command

[Keith Seitz]

On Thu, 25 Jul 2002, Mo DeJong wrote:

> It would? I was under the impression that -stack-info-depth would return
> the number of frames on the stack without taking what the current frame
> is into account.

Ah, fooey. Brain fart. You're right. My bad...

Keith