Re: GDB integration and lexical cuckholding

[Jose E. Marchesi]

> Hi Jose.
>
> On Wed, Sep 25, 2024 at 09:54:38AM GMT, Jose E. Marchesi wrote:
>> 
>> > Hi Jose.
>> >
>> > On Tue, Sep 24, 2024 at 12:02:03PM GMT, Jose E. Marchesi wrote:
>> >> 
>> >> Hi Mohammad.
>> >> 
>> >> Among my notes I found this:
>> >> 
>> >> ** TODO poke: gdb: disable lexical cuckolding in case of error in 
>> >> compile-buffer!
>> >>   [2023-05-12 Fri]
>> >> 
>> >> It may be still relevant in the current code.  Can you please take a
>> >> look?
>> >
>> >
>> > Can you elaborate a little?
>> > Lexical cuckolding continues to work after giving invalid code to Poke 
>> > compiler.
>> 
>> I don't remember exactly what prompted me to write down that note.
>> 
>> But I think it was the fact that in the poke application lexical
>> cuckolding is enabled only when code is executed from the prompt.
>> Therefore, if you have this in a foo.pk:
>> 
>>   $<foo>;
>> 
>> And then do:
>> 
>>   $ poke -l foo.pk
>>   foo.pk:1:1: error: syntax error: unexpected token
>> 
>> i.e. the token is not recognized.  But if you load it from the prompt:
>> 
>>   (p0:big:poke) load foo
>>   foo.pk:1:1: error: invalid IO space
>>   $<foo>;
>>   ^~~~~~
>> 
>> i.e. now the token is recognized.
>> 
>> I know think I wrote that note about poke, not the GDB integration,
>> because I see pk-cmd.c:pk_cmd_exec doesn't properly disable the lexical
>> cuckolding in case on error.  I am pushing a patch to fix that.
>> 
>
>
> Thanks for the explanation.
>
>
>> As for the GDB integration, if it makes sense to never turn off lexical
>> cuckolding then this is not an issue.  But it is difficult to reason
>> about it without seeing the code.  Can you please push it into a
>> personal branch in binutils-gdb.git?
>> 
>
> Pushed to users/mnabipoor/poke-gdb branch.

Well you see, my note was actually for the GDB integration:

static void
poke_command (const char *args, int from_tty)
{
  [...]
  pk_set_lexical_cuckolding_p (poke_compiler (), 1);

  if (pk_compile_* (...) != PK_OK || exit_exception != PK_NULL)
    goto error;

  pk_set_lexical_cuckolding_p (poke_compiler (), 0);
 error:
  [...] 
}

i.e. when there is an error in pk_{compile,execute}_ the lexical
cuckolding is not properly reset.  Just move the call down:

static void
poke_command (const char *args, int from_tty)
{
  [...]
  pk_set_lexical_cuckolding_p (poke_compiler (), 1);

  if (pk_compile_* (...) != PK_OK || exit_exception != PK_NULL)
    goto error;

 error:
  pk_set_lexical_cuckolding_p (poke_compiler (), 0);
  [...] 
}

I would also rename that label from `error' to `done' or similar.