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
lower_impl(nir_function_impl * impl)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 /* The edge flag is the last input in st/mesa. This code is also called by
39 * i965 which calls it before any input locations are assigned.
40 */
41 assert(shader->num_inputs == 0 ||
42 shader->num_inputs == util_bitcount64(shader->info.inputs_read));
43
44 /* Lowered IO only uses intrinsics. It doesn't use variables. */
45 if (shader->info.io_lowered) {
46 assert(shader->num_outputs ==
47 util_bitcount64(shader->info.outputs_written));
48
49 /* Load an edge flag. */
50 nir_io_semantics load_sem = {0};
51 load_sem.location = VERT_ATTRIB_EDGEFLAG;
52 load_sem.num_slots = 1;
53
54 nir_ssa_def *load =
55 nir_load_input(&b, 1, 32, nir_imm_int(&b, 0),
56 .base = shader->num_inputs++,
57 .component = 0,
58 .dest_type = nir_type_float32,
59 .io_semantics = load_sem);
60
61 /* Store an edge flag. */
62 nir_io_semantics semantics = {0};
63 semantics.location = VARYING_SLOT_EDGE;
64 semantics.num_slots = 1;
65
66 nir_store_output(&b, load, nir_imm_int(&b, 0),
67 .base = shader->num_outputs++,
68 .component = 0,
69 .io_semantics = semantics,
70 .src_type = nir_type_float32,
71 .write_mask = 0x1);
72
73 nir_metadata_preserve(impl, nir_metadata_block_index |
74 nir_metadata_dominance);
75 return;
76 }
77
78 in = nir_variable_create(shader, nir_var_shader_in,
79 glsl_vec4_type(), "edgeflag_in");
80 in->data.location = VERT_ATTRIB_EDGEFLAG;
81
82 in->data.driver_location = shader->num_inputs++;
83 shader->info.inputs_read |= VERT_BIT_EDGEFLAG;
84
85 out = nir_variable_create(shader, nir_var_shader_out,
86 glsl_vec4_type(), "edgeflag_out");
87 out->data.location = VARYING_SLOT_EDGE;
88 shader->info.outputs_written |= VARYING_BIT_EDGE;
89
90 def = nir_load_var(&b, in);
91 nir_store_var(&b, out, def, 0xf);
92
93 nir_metadata_preserve(impl, nir_metadata_block_index |
94 nir_metadata_dominance);
95 }
96
nir_lower_passthrough_edgeflags(nir_shader * shader)97 void nir_lower_passthrough_edgeflags(nir_shader *shader)
98 {
99 assert(shader->info.stage == MESA_SHADER_VERTEX);
100
101 shader->info.vs.needs_edge_flag = true;
102
103 lower_impl(nir_shader_get_entrypoint(shader));
104 }
105