src/compiler/nir/nir_lower_passthrough_edgeflags.c

   1 /*
   2  * Copyright © 2015 Red Hat
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  */
  23
  24 #include "nir.h"
  25 #include "nir_builder.h"
  26
  27 static void
  28 lower_impl(nir_function_impl *impl)
  29 {
  30    nir_shader *shader = impl->function->shader;
  31    nir_builder b;
  32    nir_variable *in, *out;
  33    nir_ssa_def *def;
  34
  35    nir_builder_init(&b, impl);
  36    b.cursor = nir_before_cf_list(&impl->body);
  37
  38    in  = nir_variable_create(shader, nir_var_shader_in,
  39                              glsl_vec4_type(), "edgeflag_in");
  40    in->data.location = VERT_ATTRIB_EDGEFLAG;
  41
  42    /* The edge flag is the last input in st/mesa. */
  43    assert(shader->num_inputs == util_bitcount64(shader->info.inputs_read));
  44    in->data.driver_location = shader->num_inputs++;
  45    shader->info.inputs_read |= BITFIELD64_BIT(VERT_ATTRIB_EDGEFLAG);
  46
  47    out = nir_variable_create(shader, nir_var_shader_out,
  48                              glsl_vec4_type(), "edgeflag_out");
  49    out->data.location = VARYING_SLOT_EDGE;
  50
  51    def = nir_load_var(&b, in);
  52    nir_store_var(&b, out, def, 0xf);
  53
  54    nir_metadata_preserve(impl, nir_metadata_block_index |
  55                                nir_metadata_dominance);
  56 }
  57
  58 void nir_lower_passthrough_edgeflags(nir_shader *shader)
  59 {
  60    lower_impl(nir_shader_get_entrypoint(shader));
  61 }