[PATCH/RFC] Move the cmdarg before load execarg

[PATCH/RFC] Move the cmdarg before load execarg

[Hui Zhu]

Hi,

I got following trouble:
gdb -q -ex "set gnutarget elf32-littlearm" ./vmlinux
"/home/teawater/kernel/barm_versatile_926ejs/vmlinux": not in
executable format: File format is ambiguous.
Matching formats: elf32-littlearm elf32-littlearm-symbian
elf32-littlearm-vxworks.
Use "set gnutarget format-name" to specify the format.

Even if I use -ex to exec the command to set the gnutarget, but it is
useless because cmdarg is exec after the vmlinux load.

I think -ex should have more high level than others.  So I make a
patch let it exec before load execarg.
What do you think about it?

Thanks,
Hui

2011-01-28  Hui Zhu  <teawater@gmail.com>

	* main.c (captured_main): Move the cmdarg code.


---
 main.c |   22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

--- a/main.c
+++ b/main.c
@@ -823,6 +823,17 @@ captured_main (void *data)
     catch_command_errors (directory_switch, dirarg[i], 0, RETURN_MASK_ALL);
   xfree (dirarg);

+  for (i = 0; i < ncmd; i++)
+    {
+      if (cmdarg[i].type == CMDARG_FILE)
+        catch_command_errors (source_script, cmdarg[i].string,
+			      !batch_flag, RETURN_MASK_ALL);
+      else  /* cmdarg[i].type == CMDARG_COMMAND */
+        catch_command_errors (execute_command, cmdarg[i].string,
+			      !batch_flag, RETURN_MASK_ALL);
+    }
+  xfree (cmdarg);
+
   /* Skip auto-loading section-specified scripts until we've sourced
      local_gdbinit (which is often used to augment the source search
      path).  */
@@ -900,17 +911,6 @@ captured_main (void *data)
   ALL_OBJFILES (objfile)
     load_auto_scripts_for_objfile (objfile);

-  for (i = 0; i < ncmd; i++)
-    {
-      if (cmdarg[i].type == CMDARG_FILE)
-        catch_command_errors (source_script, cmdarg[i].string,
-			      !batch_flag, RETURN_MASK_ALL);
-      else  /* cmdarg[i].type == CMDARG_COMMAND */
-        catch_command_errors (execute_command, cmdarg[i].string,
-			      !batch_flag, RETURN_MASK_ALL);
-    }
-  xfree (cmdarg);
-
   /* Read in the old history after all the command files have been
      read.  */
   init_history ();

Re: [PATCH/RFC] Move the cmdarg before load execarg

[Jan Kratochvil]

On Fri, 28 Jan 2011 07:41:22 +0100, Hui Zhu wrote:
> I got following trouble:
> gdb -q -ex "set gnutarget elf32-littlearm" ./vmlinux
> "/home/teawater/kernel/barm_versatile_926ejs/vmlinux": not in executable format: File format is ambiguous.
> Matching formats: elf32-littlearm elf32-littlearm-symbian elf32-littlearm-vxworks.
> Use "set gnutarget format-name" to specify the format.
> 
> Even if I use -ex to exec the command to set the gnutarget, but it is
> useless because cmdarg is exec after the vmlinux load.
> 
> I think -ex should have more high level than others.  So I make a
> patch let it exec before load execarg.
> What do you think about it?

It apparently breaks the much more common case of:
	gdb program -ex 'b main'

You should just use:
	gdb -q -ex "set gnutarget elf32-littlearm" -ex "file ./vmlinux"

as changing options required before the image load is generally an advanced
topic so I guess the "file" command requirement is OK in such case.


Thanks,
Jan

Re: [PATCH/RFC] Move the cmdarg before load execarg

[Tom Tromey]

>>>>> "Jan" == Jan Kratochvil <jan.kratochvil@redhat.com> writes:

Jan> It apparently breaks the much more common case of:
Jan> 	gdb program -ex 'b main'

FWIW, I think backward compatibility here is more important than whether
or not the options are defined in the best way possible.  In this case
it is especially true, since there is a fairly reasonable workaround.

Tom

Re: [PATCH/RFC] Move the cmdarg before load execarg

[Hui Zhu]

On Fri, Jan 28, 2011 at 20:11, Tom Tromey <tromey@redhat.com> wrote:
>>>>>> "Jan" == Jan Kratochvil <jan.kratochvil@redhat.com> writes:
>
> Jan> It apparently breaks the much more common case of:
> Jan>    gdb program -ex 'b main'
>
> FWIW, I think backward compatibility here is more important than whether
> or not the options are defined in the best way possible.  In this case
> it is especially true, since there is a fairly reasonable workaround.
>
> Tom
>

Agree with you.

Do you think we can add some other options to let gdb exec some
command before load the file?
Cause my gdb support multi-arch, but need "set gnutarget" everytime
when I use it.  So I want add a alias in my bashrc like alias
arm-gdb='gdb -ex "set gnutarget"' or a shell to make it works better.

Thanks,
Hui

Re: [PATCH/RFC] Move the cmdarg before load execarg

[Jan Kratochvil]

On Sun, 30 Jan 2011 01:31:46 +0100, Hui Zhu wrote:
> Do you think we can add some other options to let gdb exec some
> command before load the file?
> Cause my gdb support multi-arch, but need "set gnutarget" everytime
> when I use it.  So I want add a alias in my bashrc like alias
> arm-gdb='gdb -ex "set gnutarget"' or a shell to make it works better.

~/.gdbinit is read before anything else.

first: mv ~/.gdbinit ~/.gdbinit2

alias arm-gdb='echo -e "set gnutarget elf32-littlearm\nsource ~/.gdbinit2" >~/.gdbinit; /usr/bin/gdb'
alias gdb='echo -e "source ~/.gdbinit2" >~/.gdbinit; /usr/bin/gdb'


Regards,
Jan

Re: [PATCH/RFC] Move the cmdarg before load execarg

[Hui Zhu]

On Mon, Jan 31, 2011 at 19:04, Jan Kratochvil <jan.kratochvil@redhat.com> wrote:
> On Sun, 30 Jan 2011 01:31:46 +0100, Hui Zhu wrote:
>> Do you think we can add some other options to let gdb exec some
>> command before load the file?
>> Cause my gdb support multi-arch, but need "set gnutarget" everytime
>> when I use it.  So I want add a alias in my bashrc like alias
>> arm-gdb='gdb -ex "set gnutarget"' or a shell to make it works better.
>
> ~/.gdbinit is read before anything else.
>
> first: mv ~/.gdbinit ~/.gdbinit2
>
> alias arm-gdb='echo -e "set gnutarget elf32-littlearm\nsource ~/.gdbinit2" >~/.gdbinit; /usr/bin/gdb'
> alias gdb='echo -e "source ~/.gdbinit2" >~/.gdbinit; /usr/bin/gdb'
>
>
> Regards,
> Jan
>

Thanks Jan.  This way is cool.

Hui

Re: [PATCH/RFC] Move the cmdarg before load execarg

[Tom Tromey]

>> Do you think we can add some other options to let gdb exec some
>> command before load the file?

I view new options with suspicion by default.  But, I have not really
thought about this one much, so I can't really say.

>> Cause my gdb support multi-arch, but need "set gnutarget" everytime
>> when I use it.  So I want add a alias in my bashrc like alias
>> arm-gdb='gdb -ex "set gnutarget"' or a shell to make it works better.

You can always make a little shell script wrapper that does exactly what
you want.

Tom