1 /*
2 * Copyright © 2015 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.h"
25 #include "nir_builder.h"
26
27 static nir_intrinsic_instr *
as_intrinsic(nir_instr * instr,nir_intrinsic_op op)28 as_intrinsic(nir_instr *instr, nir_intrinsic_op op)
29 {
30 if (instr->type != nir_instr_type_intrinsic)
31 return NULL;
32
33 nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
34 if (intrin->intrinsic != op)
35 return NULL;
36
37 return intrin;
38 }
39
40 static nir_intrinsic_instr *
as_set_vertex_and_primitive_count(nir_instr * instr)41 as_set_vertex_and_primitive_count(nir_instr *instr)
42 {
43 return as_intrinsic(instr, nir_intrinsic_set_vertex_and_primitive_count);
44 }
45
46 /**
47 * Count the number of vertices/primitives emitted by a geometry shader per stream.
48 * If a constant number of vertices is emitted, the output is set to
49 * that number, otherwise it is unknown at compile time and the
50 * result will be -1.
51 *
52 * This only works if you've used nir_lower_gs_intrinsics() to do vertex
53 * counting at the NIR level.
54 */
55 void
nir_gs_count_vertices_and_primitives(const nir_shader * shader,int * out_vtxcnt,int * out_prmcnt,unsigned num_streams)56 nir_gs_count_vertices_and_primitives(const nir_shader *shader,
57 int *out_vtxcnt,
58 int *out_prmcnt,
59 unsigned num_streams)
60 {
61 assert(num_streams);
62
63 int vtxcnt_arr[4] = {-1, -1, -1, -1};
64 int prmcnt_arr[4] = {-1, -1, -1, -1};
65 bool cnt_found[4] = {false, false, false, false};
66
67 nir_foreach_function(function, shader) {
68 if (!function->impl)
69 continue;
70
71 /* set_vertex_and_primitive_count intrinsics only appear in predecessors of the
72 * end block. So we don't need to walk all of them.
73 */
74 set_foreach(function->impl->end_block->predecessors, entry) {
75 nir_block *block = (nir_block *) entry->key;
76
77 nir_foreach_instr_reverse(instr, block) {
78 nir_intrinsic_instr *intrin = as_set_vertex_and_primitive_count(instr);
79 if (!intrin)
80 continue;
81
82 unsigned stream = nir_intrinsic_stream_id(intrin);
83 if (stream >= num_streams)
84 continue;
85
86 int vtxcnt = -1;
87 int prmcnt = -1;
88
89 /* If the number of vertices/primitives is compile-time known, we use that,
90 * otherwise we leave it at -1 which means that it's unknown.
91 */
92 if (nir_src_is_const(intrin->src[0]))
93 vtxcnt = nir_src_as_int(intrin->src[0]);
94 if (nir_src_is_const(intrin->src[1]))
95 prmcnt = nir_src_as_int(intrin->src[1]);
96
97 /* We've found contradictory set_vertex_and_primitive_count intrinsics.
98 * This can happen if there are early-returns in main() and
99 * different paths emit different numbers of vertices.
100 */
101 if (cnt_found[stream] && vtxcnt != vtxcnt_arr[stream])
102 vtxcnt = -1;
103 if (cnt_found[stream] && prmcnt != prmcnt_arr[stream])
104 prmcnt = -1;
105
106 vtxcnt_arr[stream] = vtxcnt;
107 prmcnt_arr[stream] = prmcnt;
108 cnt_found[stream] = true;
109 }
110 }
111 }
112
113 if (out_vtxcnt)
114 memcpy(out_vtxcnt, vtxcnt_arr, num_streams * sizeof(int));
115 if (out_prmcnt)
116 memcpy(out_prmcnt, prmcnt_arr, num_streams * sizeof(int));
117 }
118