[Mesa-dev] [PATCH] glsl: Fix memory leak in builtin_builder::_image_prototype.

[Iago Toral]

On Fri, 2014-10-03 at 13:27 +0300, Francisco Jerez wrote:
> Kenneth Graunke <kenneth at whitecape.org> writes:
> 
> > On Thursday, October 02, 2014 11:28:35 AM Ian Romanick wrote:
> >> Since this is Curro's code, I'm CC'ing me.
> >> 
> >> On 10/01/2014 03:12 AM, Iago Toral Quiroga wrote:
> >> > in_var calls the ir_variable constructor, which dups the variable name.
> >> > ---
> >> >  src/glsl/builtin_functions.cpp | 8 +++++---
> >> >  1 file changed, 5 insertions(+), 3 deletions(-)
> >> > 
> >> > diff --git a/src/glsl/builtin_functions.cpp b/src/glsl/builtin_functions.cpp
> >> > index 5a024cb..7d61fcc 100644
> >> > --- a/src/glsl/builtin_functions.cpp
> >> > +++ b/src/glsl/builtin_functions.cpp
> >> > @@ -4465,9 +4465,11 @@ builtin_builder::_image_prototype(const glsl_type *image_type,
> >> >        sig->parameters.push_tail(in_var(glsl_type::int_type, "sample"));
> >> >  
> >> >     /* Data arguments. */
> >> > -   for (unsigned i = 0; i < num_arguments; ++i)
> >> > -      sig->parameters.push_tail(in_var(data_type,
> >> > -                                       ralloc_asprintf(NULL, "arg%d", i)));
> >> > +   for (unsigned i = 0; i < num_arguments; ++i) {
> >> > +      char *arg_name = ralloc_asprintf(NULL, "arg%d", i);
> >> > +      sig->parameters.push_tail(in_var(data_type, arg_name));
> >> > +      ralloc_free(arg_name);
> >> > +   }
> >> 
> >> Using a NULL memory context is generally bad... precisely because it
> >> often leads to memory leaks.
> >> 
> >> There are a couple ways to fix this.  Since all of the image functions
> >> have a limited number of parameters, we could either:
> >> 
> >>  - Have a fixed size buffer that we snprintf to.
> >> 
> >>  - Have a table of all the parameter names.
> >> 
> >>  - Since this is the function prototype, I don't think we need names for
> >> the parameters at all.  Just pass NULL?
> >
> > Does anything even use the names?  I don't think anything does...at which point, why not just call them all "arg" and be done with it?
> >
> 
> Aren't the names useful for debugging and error reporting?  But sure,
> you're right that "arg1" isn't a lot more meaningful than "arg".

Francisco: so I understand that you would be okay with just passing
"arg" for all these parameters as Kenneth suggested? I can send the
patch for this if we agree to do this.

Iago