[Mesa-dev] [PATCH 09/13] st/glsl_to_tgsi: mark "gaps" in input/output arrays as used

[Edward O'Callaghan]

On 10/08/2016 06:55 AM, Nicolai Hähnle wrote:
> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
> 
> In some cases, a shader may have an input/output array but not use some
> entries in the middle. This happens with eON games, for example.
> 
> We emit declarations that cover the entire array range even if there are
> some unused gaps. This patch now reflects that in the InputsRead etc.
> fields to ensure the various input/outputMapping arrays are actually
> correct, which will be important when we re-jiggle the way declarations
> are emitted.
> ---
>  src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 32 ++++++++++++++++++++++--------
>  1 file changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> index 66ce24c..aac80ee 100644
> --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> @@ -2451,68 +2451,84 @@ glsl_to_tgsi_visitor::visit(ir_dereference_variable *ir)
>     this->result = st_src_reg(entry->file, entry->index, var->type);
>     this->result.array_id = entry->array_id;
>     if (this->shader->Stage == MESA_SHADER_VERTEX && var->data.mode == ir_var_shader_in && var->type->is_double())
>        this->result.is_double_vertex_input = true;
>     if (!native_integers)
>        this->result.type = GLSL_TYPE_FLOAT;
>  }
>  
>  static void
>  shrink_array_declarations(struct array_decl *arrays, unsigned count,
> -                          GLbitfield64 usage_mask,
> +                          GLbitfield64* usage_mask,
>                            GLbitfield64 double_usage_mask,
> -                          GLbitfield patch_usage_mask)
> +                          GLbitfield* patch_usage_mask)
>  {
>     unsigned i;
>     int j;
>  
>     /* Fix array declarations by removing unused array elements at both ends
>      * of the arrays. For example, mat4[3] where only mat[1] is used.
>      */
>     for (i = 0; i < count; i++) {
>        struct array_decl *decl = &arrays[i];
>  
>        /* Shrink the beginning. */
>        for (j = 0; j < (int)decl->array_size; j++) {
>           if (decl->mesa_index >= VARYING_SLOT_PATCH0) {
> -            if (patch_usage_mask &
> +            if (*patch_usage_mask &
>                  BITFIELD64_BIT(decl->mesa_index - VARYING_SLOT_PATCH0 + j))
>                 break;
>           }
>           else {
> -            if (usage_mask & BITFIELD64_BIT(decl->mesa_index+j))
> +            if (*usage_mask & BITFIELD64_BIT(decl->mesa_index+j))
>                 break;
>              if (double_usage_mask & BITFIELD64_BIT(decl->mesa_index+j-1))
>                 break;
>           }
>  
>           decl->mesa_index++;
>           decl->array_size--;
>           j--;
>        }
>  
>        /* Shrink the end. */
>        for (j = decl->array_size-1; j >= 0; j--) {
>           if (decl->mesa_index >= VARYING_SLOT_PATCH0) {
> -            if (patch_usage_mask &
> +            if (*patch_usage_mask &
>                  BITFIELD64_BIT(decl->mesa_index - VARYING_SLOT_PATCH0 + j))
>                 break;
>           }
>           else {
> -            if (usage_mask & BITFIELD64_BIT(decl->mesa_index+j))
> +            if (*usage_mask & BITFIELD64_BIT(decl->mesa_index+j))
>                 break;
>              if (double_usage_mask & BITFIELD64_BIT(decl->mesa_index+j-1))
>                 break;
>           }
>  
>           decl->array_size--;
>        }
> +
> +      /* When not all entries of an array are accessed, we mark them as uesd

s/uesd/used/

> +       * here anyway, to ensure that the input/output mapping logic doesn't get
> +       * confused.
> +       *
> +       * TODO This happens when an array isn't used via indirect access, which
> +       * some game ports do (at least eON-based). There is an optimization
> +       * opportunity here by replacing the array declaration with non-array
> +       * declarations of those slots that are actually used.
> +       */
> +      for (j = 1; j < (int)decl->array_size; ++j) {
> +         if (decl->mesa_index >= VARYING_SLOT_PATCH0)
> +            *patch_usage_mask |= BITFIELD64_BIT(decl->mesa_index - VARYING_SLOT_PATCH0 + j);
> +         else
> +            *usage_mask |= BITFIELD64_BIT(decl->mesa_index + j);
> +      }
>     }
>  }
>  
>  void
>  glsl_to_tgsi_visitor::visit(ir_dereference_array *ir)
>  {
>     ir_constant *index;
>     st_src_reg src;
>     int element_size = type_size(ir->type);
>     bool is_2D = false;
> @@ -6624,23 +6640,23 @@ get_mesa_program_tgsi(struct gl_context *ctx,
>               shader_program->Name);
>        _mesa_print_ir(_mesa_get_log_file(), shader->ir, NULL);
>        _mesa_log("\n\n");
>     }
>  
>     prog->Instructions = NULL;
>     prog->NumInstructions = 0;
>  
>     do_set_program_inouts(shader->ir, prog, shader->Stage);
>     shrink_array_declarations(v->input_arrays, v->num_input_arrays,
> -                             prog->InputsRead, prog->DoubleInputsRead, prog->PatchInputsRead);
> +                             &prog->InputsRead, prog->DoubleInputsRead, &prog->PatchInputsRead);
>     shrink_array_declarations(v->output_arrays, v->num_output_arrays,
> -                             prog->OutputsWritten, 0ULL, prog->PatchOutputsWritten);
> +                             &prog->OutputsWritten, 0ULL, &prog->PatchOutputsWritten);
>     count_resources(v, prog);
>  
>     /* The GLSL IR won't be needed anymore. */
>     ralloc_free(shader->ir);
>     shader->ir = NULL;
>  
>     /* This must be done before the uniform storage is associated. */
>     if (shader->Stage == MESA_SHADER_FRAGMENT &&
>         (prog->InputsRead & VARYING_BIT_POS ||
>          prog->SystemValuesRead & (1 << SYSTEM_VALUE_FRAG_COORD))) {
> 

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