[Mesa-dev] [PATCH 1/3] glsl: Add a new matching_signature() variant that returns exact/inexact.

[Paul Berry]

On 11 November 2011 02:56, Kenneth Graunke <kenneth at whitecape.org> wrote:

> When matching function signatures across multiple linked shaders, we
> often want to see if the current shader has _any_ match, but also know
> whether or not it was exact.  (If not, we may want to keep looking.)
>
> This could be done via the existing mechanisms:
>
>   sig = f->exact_matching_signature(params);
>   if (sig != NULL) {
>      exact = true;
>   } else {
>      sig = f->matching_signature(params);
>      exact = false;
>   }
>
> However, this requires walking the list of function signatures twice,
> which also means walking each signature's formal parameter lists twice.
> This could be rather expensive.
>
> Since matching_signature already internally knows whether a match was
> exact or not, we can just return it to get that information for free.
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
>  src/glsl/ir.h            |    7 +++++++
>  src/glsl/ir_function.cpp |   11 +++++++++++
>  2 files changed, 18 insertions(+), 0 deletions(-)
>
> diff --git a/src/glsl/ir.h b/src/glsl/ir.h
> index 5878c05..6d40913 100644
> --- a/src/glsl/ir.h
> +++ b/src/glsl/ir.h
> @@ -566,6 +566,13 @@ public:
>
>    /**
>     * Find a signature that matches a set of actual parameters, taking
> implicit
> +    * conversions into account.  Also flags whether the match was exact.
> +    */
> +   ir_function_signature *matching_signature(const exec_list
> *actual_param,
> +                                            bool &match_is_exact);
>

Minor quibble: I'd prefer to make match_is_exact a pointer, so that in the
caller, it's obvious that the value of match_is_exact is going to be
changed.

In any case, this patch is:

Reviewed-by: Paul Berry <stereotype441 at gmail.com>
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