Re: [PATCH vkd3d 3/5] vkd3d-shader: Implement multiplication and division.

[Zebediah Figura (she/her)]

On 1/19/21 4:24 AM, Matteo Bruni wrote:
> On Mon, Jan 18, 2021 at 10:34 PM Zebediah Figura
>  wrote:
> > Signed-off-by: Zebediah Figura
> >
> > libs/vkd3d-shader/preproc.l |  2 +-
> >  libs/vkd3d-shader/preproc.y | 24 ++++++++++++++++++++++--
> >  2 files changed, 23 insertions(+), 3 deletions(-)
> >
> > diff --git a/libs/vkd3d-shader/preproc.l b/libs/vkd3d-shader/preproc.l
> > index 011f8dbb..a522b7c8 100644
> > --- a/libs/vkd3d-shader/preproc.l
> > +++ b/libs/vkd3d-shader/preproc.l
> > @@ -157,7 +157,7 @@ IDENTIFIER      [A-Za-z_][A-Za-z0-9_]*
> >      }
> >
> > <INITIAL>{WS}+                      {}
> > -<INITIAL>[-()[]{},+!]             {return yytext[0];}
> > +<INITIAL>[-()[]{},+!*/]           {return yytext[0];}
> >  <INITIAL>.                          {return T_TEXT;}
> >
> > %%
> > diff --git a/libs/vkd3d-shader/preproc.y b/libs/vkd3d-shader/preproc.y
> > index 51df5d40..1060e9d7 100644
> > --- a/libs/vkd3d-shader/preproc.y
> > +++ b/libs/vkd3d-shader/preproc.y
> > @@ -335,6 +335,7 @@ static void free_parse_arg_names(struct parse_arg_names *args)
> >
> > %type <integer> primary_expr
> >  %type <integer> unary_expr
> > +%type <integer> mul_expr
> >  %type <string> body_token
> >  %type <const_string> body_token_const
> >  %type <string_buffer> body_text
> > @@ -439,6 +440,14 @@ body_token_const
> >          {
> >              $$ = "!";
> >          }
> > - | '*'
> > -
> >    {
> > -
> >        $$ = "*";
> > -
> >    }
> > - | '/'
> > -
> >    {
> > -
> >        $$ = "/";
> > -
> >    }
> > | T_CONCAT
> >        {
> >            $$ = "##";
> >
> > @@ -480,7 +489,7 @@ directive
> >              }
> >              vkd3d_free($2);
> >          }
> > - | T_IF unary_expr T_NEWLINE
> > - | T_IF mul_expr T_NEWLINE
> >     {
> >         if (!preproc_push_if(ctx, !!$2))
> >             YYABORT;
> >
> > @@ -495,7 +504,7 @@ directive
> >              preproc_push_if(ctx, !preproc_find_macro(ctx, $2));
> >              vkd3d_free($2);
> >          }
> > - | T_ELIF unary_expr T_NEWLINE
> > - | T_ELIF mul_expr T_NEWLINE
> >     {
> >         const struct preproc_file *file = preproc_get_top_file(ctx);
> >
> > @@ -631,3 +640,14 @@ unary_expr
> >          {
> >              $$ = !$2;
> >          }
> > -
> >
> > +mul_expr
> > - : unary_expr
> > - | mul_expr '*' unary_expr
> > -
> >    {
> > -
> >        $$ = $1 * $3;
> > -
> >    }
> > - | mul_expr '/' unary_expr
> > -
> >    {
> > -
> >        $$ = $1 / $3;
> > -
> >    }
>
> I don't know that we care but notice that e.g. "#if 1 / 0" causes a
> floating point exception.

Yes, that probably shouldn't be allowed to crash the preprocessor,
thanks for catching that.