[PING] [PATCH v3] guile: stop procedures on invalid breakpoints

[George Barrett <bob@bob131.so>]

Pinging. If everything looks alright, I'd appreciate if someone could
merge it on my behalf.

Thanks.

On Thu, Jul 29, 2021 at 09:16:41 +1000, George Barrett wrote:
> Stop procedures on <gdb:breakpoint> objects are independent of the
> breakpoints in GDB core: the only reference made to the GDB breakpoint
> pointer in either of `breakpoint-stop' or `set-breakpoint-stop!' is in
> the latter checking to ensure that there hasn't already been a stop
> condition attached from elsewhere. This check is not applicable to
> not-yet-registered <gdb:breakpoint> objects allocated from Scheme.
>
> This commit changes the above-mentioned procedures to accept invalid
> <gdb:breakpoint> objects originating from Scheme; this allows the
> decoupling of the creation of a specific breakpoint object from its
> registration (as well as making the interface less restrictive than it
> needs to be).
>
> gdb/ChangeLog:
>
> 2021-07-29  George Barrett  <bob@bob131.so>
>
> 	* guile/scm-breakpoint.c
> 	(bpscm_get_valid_or_scm_breakpoint_smob_arg_unsafe): Add
> 	helper function.
> 	(gdbscm_breakpoint_stop): Use
> 	bpscm_get_valid_or_scm_breakpoint_smob_arg_unsafe.
> 	(gdbscm_set_breakpoint_stop_x): Likewise.  Check that bp is
> 	non-NULL before doing condition string tests.
>
> gdb/doc/ChangeLog:
>
> 2021-07-29  George Barrett  <bob@bob131.so>
>
> 	* guile.texi (Breakpoints In Guile): Add note that
> 	breakpoint-stop and set-breakpoint-stop! may be used on
> 	invalid <gdb:breakpoint> objects if they originated from
> 	Scheme.
>
> gdb/testsuite/ChangeLog:
>
> 2021-07-29  George Barrett  <bob@bob131.so>
>
> 	* gdb.guile/scm-breakpoint.exp (test_bkpt_eval_funcs): Add
> 	tests for stop procedure manipulation on invalid
> 	<gdb:breakpoint> objects originating from Scheme.
> 	Add tests for stop procedure manipulation on valid and invalid
> 	<gdb:breakpoint> objects originating from GDB core.
> ---
>  gdb/doc/guile.texi                         | 10 ++++
>  gdb/guile/scm-breakpoint.c                 | 64 +++++++++++++++-------
>  gdb/testsuite/gdb.guile/scm-breakpoint.exp | 37 ++++++++++++-
>  3 files changed, 90 insertions(+), 21 deletions(-)
>
> diff --git a/gdb/doc/guile.texi b/gdb/doc/guile.texi
> index 36fc9a7af79..602e45b6ce0 100644
> --- a/gdb/doc/guile.texi
> +++ b/gdb/doc/guile.texi
> @@ -3186,6 +3186,11 @@ becomes unconditional.
>  @deffn {Scheme Procedure} breakpoint-stop breakpoint
>  Return the stop predicate of @var{breakpoint}.
>  See @code{set-breakpoint-stop!} below in this section.
> +
> +If @var{breakpoint} was created using @code{make-breakpoint}, this
> +procedure may be used even if @code{breakpoint-valid?} would return
> +@code{#f}.  In that case it returns the stop procedure that will be used
> +by @var{breakpoint} once the breakpoint has been registered.
>  @end deffn
>  
>  @deffn {Scheme Procedure} set-breakpoint-stop! breakpoint procedure|#f
> @@ -3219,6 +3224,11 @@ Example @code{stop} implementation:
>  (register-breakpoint! bkpt)
>  (set-breakpoint-stop! bkpt my-stop?)
>  @end smallexample
> +
> +If @var{breakpoint} was created using @code{make-breakpoint}, this
> +procedure may be used even if @code{breakpoint-valid?} would return
> +@code{#f}.  In that case @var{procedure} will be the stop procedure for
> +@var{breakpoint} when the breakpoint is registered.
>  @end deffn
>  
>  @deffn {Scheme Procedure} breakpoint-commands breakpoint
> diff --git a/gdb/guile/scm-breakpoint.c b/gdb/guile/scm-breakpoint.c
> index 3f25708afff..32a6e3e4164 100644
> --- a/gdb/guile/scm-breakpoint.c
> +++ b/gdb/guile/scm-breakpoint.c
> @@ -328,6 +328,25 @@ bpscm_get_valid_breakpoint_smob_arg_unsafe (SCM self, int arg_pos,
>  
>    return bp_smob;
>  }
> +
> +/* Returns the breakpoint smob in SELF, verifying it's either valid or
> +   originates from Scheme.
> +   Throws an exception if SELF is not a <gdb:breakpoint> object,
> +   or is invalid and not allocated from Scheme.  */
> +
> +static breakpoint_smob *
> +bpscm_get_valid_or_scm_breakpoint_smob_arg_unsafe (SCM self, int arg_pos,
> +						   const char *func_name)
> +{
> +  breakpoint_smob *bp_smob
> +    = bpscm_get_breakpoint_smob_arg_unsafe (self, arg_pos, func_name);
> +
> +  if (!bpscm_is_valid (bp_smob) && !bp_smob->is_scheme_bkpt)
> +    gdbscm_invalid_object_error (func_name, arg_pos, self,
> +				 _("<gdb:breakpoint>"));
> +
> +  return bp_smob;
> +}
>  \f
>  /* Breakpoint methods.  */
>  
> @@ -928,7 +947,8 @@ static SCM
>  gdbscm_breakpoint_stop (SCM self)
>  {
>    breakpoint_smob *bp_smob
> -    = bpscm_get_valid_breakpoint_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);
> +    = bpscm_get_valid_or_scm_breakpoint_smob_arg_unsafe (self, SCM_ARG1,
> +							 FUNC_NAME);
>  
>    return bp_smob->stop;
>  }
> @@ -940,32 +960,36 @@ static SCM
>  gdbscm_set_breakpoint_stop_x (SCM self, SCM newvalue)
>  {
>    breakpoint_smob *bp_smob
> -    = bpscm_get_valid_breakpoint_smob_arg_unsafe (self, SCM_ARG1, FUNC_NAME);
> -  const struct extension_language_defn *extlang = NULL;
> +    = bpscm_get_valid_or_scm_breakpoint_smob_arg_unsafe (self, SCM_ARG1,
> +							 FUNC_NAME);
>  
>    SCM_ASSERT_TYPE (gdbscm_is_procedure (newvalue)
>  		   || gdbscm_is_false (newvalue),
>  		   newvalue, SCM_ARG2, FUNC_NAME,
>  		   _("procedure or #f"));
>  
> -  if (bp_smob->bp->cond_string != NULL)
> -    extlang = get_ext_lang_defn (EXT_LANG_GDB);
> -  if (extlang == NULL)
> -    extlang = get_breakpoint_cond_ext_lang (bp_smob->bp, EXT_LANG_GUILE);
> -  if (extlang != NULL)
> +  if (bp_smob->bp != nullptr)
>      {
> -      char *error_text
> -	= xstrprintf (_("Only one stop condition allowed.  There is"
> -			" currently a %s stop condition defined for"
> -			" this breakpoint."),
> -		      ext_lang_capitalized_name (extlang));
> -
> -      scm_dynwind_begin ((scm_t_dynwind_flags) 0);
> -      gdbscm_dynwind_xfree (error_text);
> -      gdbscm_out_of_range_error (FUNC_NAME, SCM_ARG1, self, error_text);
> -      /* The following line, while unnecessary, is present for completeness
> -	 sake.  */
> -      scm_dynwind_end ();
> +      const struct extension_language_defn *extlang = nullptr;
> +      if (bp_smob->bp->cond_string != nullptr)
> +	extlang = get_ext_lang_defn (EXT_LANG_GDB);
> +      if (extlang == nullptr)
> +	extlang = get_breakpoint_cond_ext_lang (bp_smob->bp, EXT_LANG_GUILE);
> +      if (extlang != nullptr)
> +	{
> +	  char *error_text
> +	    = xstrprintf (_("Only one stop condition allowed.  There is"
> +			    " currently a %s stop condition defined for"
> +			    " this breakpoint."),
> +			  ext_lang_capitalized_name (extlang));
> +
> +	  scm_dynwind_begin ((scm_t_dynwind_flags) 0);
> +	  gdbscm_dynwind_xfree (error_text);
> +	  gdbscm_out_of_range_error (FUNC_NAME, SCM_ARG1, self, error_text);
> +	  /* The following line, while unnecessary, is present for
> +	     completeness sake.  */
> +	  scm_dynwind_end ();
> +	}
>      }
>  
>    bp_smob->stop = newvalue;
> diff --git a/gdb/testsuite/gdb.guile/scm-breakpoint.exp b/gdb/testsuite/gdb.guile/scm-breakpoint.exp
> index be898cacaa7..6964066dd34 100644
> --- a/gdb/testsuite/gdb.guile/scm-breakpoint.exp
> +++ b/gdb/testsuite/gdb.guile/scm-breakpoint.exp
> @@ -383,10 +383,45 @@ proc_with_prefix test_bkpt_eval_funcs { } {
>  	"= 4" \
>  	"check non firing same-location breakpoint eval function was also called at each stop 2"
>  
> +    # Check that stop funcs can be manipulated on invalid Scheme-created
> +    # breakpoints.
> +
> +    delete_breakpoints
> +    gdb_test "guile (print (breakpoint-valid? eval-bp1))" "= #f" \
> +	"check Scheme-created breakpoint is invalid"
> +    gdb_scm_test_silent_cmd "guile (set-breakpoint-stop! eval-bp1 (const 'test!))" \
> +	"check setting stop procedure on invalid Scheme-created breakpoint"
> +    gdb_test "guile (print ((breakpoint-stop eval-bp1)))" "= test!" \
> +	"check stop procedure on invalid Scheme-created breakpoint was successfully set"
> +
> +    # Check that stop funcs can be manipulated on breakpoint wrappers.
> +
> +    gdb_breakpoint "main"
> +    gdb_scm_test_silent_cmd "guile (define bp-wrapper (car (breakpoints)))" \
> +	"get breakpoint wrapper"
> +    gdb_test "guile (print (breakpoint-valid? bp-wrapper))" "= #t" \
> +	"check breakpoint wrapper is valid"
> +    gdb_scm_test_silent_cmd "guile (set-breakpoint-stop! bp-wrapper (const 'test!))" \
> +	"check setting stop procedure on breakpoit wrapper"
> +    gdb_test "guile (print ((breakpoint-stop bp-wrapper)))" "= test!" \
> +	"check stop procedure on breakpoint wrapper was successfully set"
> +
> +    # Check that stop funcs cannot be manipulated on invalid breakpoint
> +    # wrappers.
> +
> +    delete_breakpoints
> +    gdb_test "guile (print (breakpoint-valid? bp-wrapper))" "= #f" \
> +	"check breakpoint wrapper is invalid"
> +    gdb_test "guile (set-breakpoint-stop! bp-wrapper (const 'test!))" \
> +	"ERROR:.*Invalid object: <gdb:breakpoint>.*" \
> +	"check stop procedure cannot be set on invalid breakpoint wrapper"
> +    gdb_test "guile (breakpoint-stop bp-wrapper)" \
> +	"ERROR:.*Invalid object: <gdb:breakpoint>.*" \
> +	"check stop procedure cannot be retrieved from invalid breakpoint wrapper"
> +
>      # Check we cannot assign a condition to a breakpoint with a stop-func,
>      # and cannot assign a stop-func to a breakpoint with a condition.
>  
> -    delete_breakpoints
>      set cond_bp [gdb_get_line_number "Break at multiply."]
>      gdb_scm_test_silent_cmd  "guile (define eval-bp1 (make-bp-eval \"$cond_bp\"))" \
>  	"create eval-bp1 breakpoint 2"
> -- 
> 2.31.1