[Mesa-dev] [PATCH] glsl: fix key used for hashing switch statement cases

[Iago Toral]

On Thu, 2016-08-18 at 11:57 +0300, Tapani Pälli wrote:
> Implementation previously used case value itself as the key, however
> afterhash implementation change by ee02a5e we cannot use 0 as key.
> Patch uses _mesa_hash_data to formulate a suitable key for this hash.
> 
> Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97309
> ---
>  src/compiler/glsl/ast_to_hir.cpp | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/src/compiler/glsl/ast_to_hir.cpp
> b/src/compiler/glsl/ast_to_hir.cpp
> index e03a6e3..53fc4d6 100644
> --- a/src/compiler/glsl/ast_to_hir.cpp
> +++ b/src/compiler/glsl/ast_to_hir.cpp
> @@ -6180,9 +6180,11 @@ ast_case_label::hir(exec_list *instructions,
>           /* Stuff a dummy value in to allow processing to continue.
> */
>           label_const = new(ctx) ir_constant(0);
>        } else {
> +         unsigned hash_key = _mesa_hash_data(&label_const-
> >value.u[0],
> +                                             sizeof(unsigned));

Shouldn't this take (void *) label_const->value[0] instead? It is the
value of the label we want to use as key, not the memory address where
it is stored, right?

>           ast_expression *previous_label = (ast_expression *)
>           hash_table_find(state->switch_state.labels_ht,
> -                         (void *)(uintptr_t)label_const-
> >value.u[0]);
> +                         (void *)(uintptr_t)hash_key);

Actually, you use the value here, so I guess the above was a mistake?

>           if (previous_label) {
>              YYLTYPE loc = this->test_value->get_location();
> @@ -6193,7 +6195,7 @@ ast_case_label::hir(exec_list *instructions,
>           } else {
>              hash_table_insert(state->switch_state.labels_ht,
>                                this->test_value,
> -                              (void *)(uintptr_t)label_const-
> >value.u[0]);
> +                              (void *)(uintptr_t)hash_key);
>           }
>        }
>