1 /*
2 * Copyright © 2015 Broadcom
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 "compiler/v3d_compiler.h"
25 #include "compiler/nir/nir_builder.h"
26
27 /**
28 * Walks the NIR generated by TGSI-to-NIR or GLSL-to-NIR to lower its io
29 * intrinsics into something amenable to the V3D architecture.
30 *
31 * Currently, it splits VS inputs and uniforms into scalars, drops any
32 * non-position outputs in coordinate shaders, and fixes up the addressing on
33 * indirect uniform loads. FS input and VS output scalarization is handled by
34 * nir_lower_io_to_scalar().
35 */
36
37 static void
replace_intrinsic_with_vec(nir_builder * b,nir_intrinsic_instr * intr,nir_ssa_def ** comps)38 replace_intrinsic_with_vec(nir_builder *b, nir_intrinsic_instr *intr,
39 nir_ssa_def **comps)
40 {
41
42 /* Batch things back together into a vector. This will get split by
43 * the later ALU scalarization pass.
44 */
45 nir_ssa_def *vec = nir_vec(b, comps, intr->num_components);
46
47 /* Replace the old intrinsic with a reference to our reconstructed
48 * vector.
49 */
50 nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(vec));
51 nir_instr_remove(&intr->instr);
52 }
53
54 static void
v3d_nir_lower_output(struct v3d_compile * c,nir_builder * b,nir_intrinsic_instr * intr)55 v3d_nir_lower_output(struct v3d_compile *c, nir_builder *b,
56 nir_intrinsic_instr *intr)
57 {
58 nir_variable *output_var = NULL;
59 nir_foreach_variable(var, &c->s->outputs) {
60 if (var->data.driver_location == nir_intrinsic_base(intr)) {
61 output_var = var;
62 break;
63 }
64 }
65 assert(output_var);
66
67 if (c->vs_key) {
68 int slot = output_var->data.location;
69 bool used = false;
70
71 switch (slot) {
72 case VARYING_SLOT_PSIZ:
73 case VARYING_SLOT_POS:
74 used = true;
75 break;
76
77 default:
78 for (int i = 0; i < c->vs_key->num_fs_inputs; i++) {
79 if (v3d_slot_get_slot(c->vs_key->fs_inputs[i]) == slot) {
80 used = true;
81 break;
82 }
83 }
84 break;
85 }
86
87 if (!used)
88 nir_instr_remove(&intr->instr);
89 }
90 }
91
92 static void
v3d_nir_lower_uniform(struct v3d_compile * c,nir_builder * b,nir_intrinsic_instr * intr)93 v3d_nir_lower_uniform(struct v3d_compile *c, nir_builder *b,
94 nir_intrinsic_instr *intr)
95 {
96 b->cursor = nir_before_instr(&intr->instr);
97
98 /* Generate scalar loads equivalent to the original vector. */
99 nir_ssa_def *dests[4];
100 for (unsigned i = 0; i < intr->num_components; i++) {
101 nir_intrinsic_instr *intr_comp =
102 nir_intrinsic_instr_create(c->s, intr->intrinsic);
103 intr_comp->num_components = 1;
104 nir_ssa_dest_init(&intr_comp->instr, &intr_comp->dest, 1, 32, NULL);
105
106 /* Convert the uniform offset to bytes. If it happens
107 * to be a constant, constant-folding will clean up
108 * the shift for us.
109 */
110 nir_intrinsic_set_base(intr_comp,
111 nir_intrinsic_base(intr) * 16 +
112 i * 4);
113
114 intr_comp->src[0] =
115 nir_src_for_ssa(nir_ishl(b, intr->src[0].ssa,
116 nir_imm_int(b, 4)));
117
118 dests[i] = &intr_comp->dest.ssa;
119
120 nir_builder_instr_insert(b, &intr_comp->instr);
121 }
122
123 replace_intrinsic_with_vec(b, intr, dests);
124 }
125
126 static void
v3d_nir_lower_io_instr(struct v3d_compile * c,nir_builder * b,struct nir_instr * instr)127 v3d_nir_lower_io_instr(struct v3d_compile *c, nir_builder *b,
128 struct nir_instr *instr)
129 {
130 if (instr->type != nir_instr_type_intrinsic)
131 return;
132 nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
133
134 switch (intr->intrinsic) {
135 case nir_intrinsic_load_input:
136 break;
137
138 case nir_intrinsic_store_output:
139 v3d_nir_lower_output(c, b, intr);
140 break;
141
142 case nir_intrinsic_load_uniform:
143 v3d_nir_lower_uniform(c, b, intr);
144 break;
145
146 case nir_intrinsic_load_user_clip_plane:
147 default:
148 break;
149 }
150 }
151
152 static bool
v3d_nir_lower_io_impl(struct v3d_compile * c,nir_function_impl * impl)153 v3d_nir_lower_io_impl(struct v3d_compile *c, nir_function_impl *impl)
154 {
155 nir_builder b;
156 nir_builder_init(&b, impl);
157
158 nir_foreach_block(block, impl) {
159 nir_foreach_instr_safe(instr, block)
160 v3d_nir_lower_io_instr(c, &b, instr);
161 }
162
163 nir_metadata_preserve(impl, nir_metadata_block_index |
164 nir_metadata_dominance);
165
166 return true;
167 }
168
169 void
v3d_nir_lower_io(nir_shader * s,struct v3d_compile * c)170 v3d_nir_lower_io(nir_shader *s, struct v3d_compile *c)
171 {
172 nir_foreach_function(function, s) {
173 if (function->impl)
174 v3d_nir_lower_io_impl(c, function->impl);
175 }
176 }
177