mirror of OpenBSD xenocara tree
github.com/openbsd/xenocara
openbsd
1/*
2 * Copyright © 2016 Intel Corporation
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
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24#include "nir_builder.h"
25
26static nir_variable *
27make_uniform(nir_shader *nir, const gl_state_index16 *tokens)
28{
29 /* Note: name must be prefixed with "gl_" to trigger slot based
30 * special handling in uniform setup.
31 */
32 nir_variable *var =
33 nir_state_variable_create(nir, glsl_int_type(),
34 "gl_PatchVerticesIn", tokens);
35
36 return var;
37}
38
39/**
40 * This pass lowers the load_patch_vertices_in intrinsic.
41 *
42 * - If we statically know the value, we lower it to a constant.
43 * (If a TES is linked against a TCS, the TCS tells us the TES input count.)
44 *
45 * - If not, and we're given Mesa state slots, we lower it to a uniform.
46 *
47 * - Otherwise, we leave it as a system value.
48 *
49 * This pass must be run after nir_lower_system_values().
50 */
51bool
52nir_lower_patch_vertices(nir_shader *nir,
53 unsigned static_count,
54 const gl_state_index16 *uniform_state_tokens)
55{
56 bool progress = false;
57 nir_variable *var = NULL;
58
59 /* If there's no static count and we don't want uniforms, there's no
60 * lowering to do...just bail early.
61 */
62 if (static_count == 0 && !uniform_state_tokens)
63 return false;
64
65 nir_foreach_function_impl(impl, nir) {
66 nir_foreach_block(block, impl) {
67 nir_builder b = nir_builder_create(impl);
68 nir_foreach_instr_safe(instr, block) {
69 if (instr->type == nir_instr_type_intrinsic) {
70 nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
71 if (intr->intrinsic != nir_intrinsic_load_patch_vertices_in)
72 continue;
73
74 b.cursor = nir_before_instr(&intr->instr);
75
76 nir_def *val = NULL;
77 if (static_count) {
78 val = nir_imm_int(&b, static_count);
79 } else {
80 if (!var)
81 var = make_uniform(nir, uniform_state_tokens);
82
83 val = nir_load_var(&b, var);
84 }
85
86 progress = true;
87 nir_def_replace(&intr->def, val);
88 }
89 }
90 }
91
92 if (progress) {
93 nir_metadata_preserve(impl, nir_metadata_control_flow);
94 }
95 }
96
97 return progress;
98}