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 #include "program/prog_instruction.h"
26
27 static nir_variable *
make_uniform(nir_shader * nir,const gl_state_index16 * tokens)28 make_uniform(nir_shader *nir, const gl_state_index16 *tokens)
29 {
30 /* Note: name must be prefixed with "gl_" to trigger slot based
31 * special handling in uniform setup.
32 */
33 nir_variable *var =
34 nir_variable_create(nir, nir_var_uniform, glsl_int_type(),
35 "gl_PatchVerticesIn");
36 var->num_state_slots = 1;
37 var->state_slots = ralloc_array(var, nir_state_slot, var->num_state_slots);
38 memcpy(var->state_slots[0].tokens, tokens, sizeof(*tokens) * STATE_LENGTH);
39 var->state_slots[0].swizzle = SWIZZLE_XXXX;
40
41 return var;
42 }
43
44 /**
45 * This pass lowers the load_patch_vertices_in intrinsic.
46 *
47 * - If we statically know the value, we lower it to a constant.
48 * (If a TES is linked against a TCS, the TCS tells us the TES input count.)
49 *
50 * - If not, and we're given Mesa state slots, we lower it to a uniform.
51 *
52 * - Otherwise, we leave it as a system value.
53 *
54 * This pass must be run after nir_lower_system_values().
55 */
56 bool
nir_lower_patch_vertices(nir_shader * nir,unsigned static_count,const gl_state_index16 * uniform_state_tokens)57 nir_lower_patch_vertices(nir_shader *nir,
58 unsigned static_count,
59 const gl_state_index16 *uniform_state_tokens)
60 {
61 bool progress = false;
62 nir_variable *var = NULL;
63
64 /* If there's no static count and we don't want uniforms, there's no
65 * lowering to do...just bail early.
66 */
67 if (static_count == 0 && !uniform_state_tokens)
68 return false;
69
70 nir_foreach_function(function, nir) {
71 if (function->impl) {
72 nir_foreach_block(block, function->impl) {
73 nir_builder b;
74 nir_builder_init(&b, function->impl);
75 nir_foreach_instr_safe(instr, block) {
76 if (instr->type == nir_instr_type_intrinsic) {
77 nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
78 if (intr->intrinsic != nir_intrinsic_load_patch_vertices_in)
79 continue;
80
81 b.cursor = nir_before_instr(&intr->instr);
82
83 nir_ssa_def *val = NULL;
84 if (static_count) {
85 val = nir_imm_int(&b, static_count);
86 } else {
87 if (!var)
88 var = make_uniform(nir, uniform_state_tokens);
89
90 val = nir_load_var(&b, var);
91 }
92
93 progress = true;
94 nir_ssa_def_rewrite_uses(&intr->dest.ssa,
95 val);
96 nir_instr_remove(instr);
97 }
98 }
99 }
100
101 if (progress) {
102 nir_metadata_preserve(function->impl, nir_metadata_block_index |
103 nir_metadata_dominance);
104 }
105 }
106 }
107
108 return progress;
109 }
110