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

[Eric Anholt]

Tapani Pälli <tapani.palli at intel.com> writes:

> 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));
>           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);
>  
>           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);

_mesa_hash_data(...) could *also* be zero.  It'll only probably be that
for about one possible input value, but still.

Instead, we should change from _mesa_pointer_hash/compare to a thing
using _mesa_hash_data in HT setup, and pass pointer to the value.u[0]
here.
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