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

[Francisco Jerez]

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".

> --Ken
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