mesa/src/compiler/nir/nir_gs_count_vertices.c

118 lines
4.2 KiB
C

/*
* Copyright © 2015 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "nir.h"
#include "nir_builder.h"
static nir_intrinsic_instr *
as_intrinsic(nir_instr *instr, nir_intrinsic_op op)
{
if (instr->type != nir_instr_type_intrinsic)
return NULL;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
if (intrin->intrinsic != op)
return NULL;
return intrin;
}
static nir_intrinsic_instr *
as_set_vertex_and_primitive_count(nir_instr *instr)
{
return as_intrinsic(instr, nir_intrinsic_set_vertex_and_primitive_count);
}
/**
* Count the number of vertices/primitives emitted by a geometry shader per stream.
* If a constant number of vertices is emitted, the output is set to
* that number, otherwise it is unknown at compile time and the
* result will be -1.
*
* This only works if you've used nir_lower_gs_intrinsics() to do vertex
* counting at the NIR level.
*/
void
nir_gs_count_vertices_and_primitives(const nir_shader *shader,
int *out_vtxcnt,
int *out_prmcnt,
unsigned num_streams)
{
assert(num_streams);
int vtxcnt_arr[4] = {-1, -1, -1, -1};
int prmcnt_arr[4] = {-1, -1, -1, -1};
bool cnt_found[4] = {false, false, false, false};
nir_foreach_function(function, shader) {
if (!function->impl)
continue;
/* set_vertex_and_primitive_count intrinsics only appear in predecessors of the
* end block. So we don't need to walk all of them.
*/
set_foreach(function->impl->end_block->predecessors, entry) {
nir_block *block = (nir_block *) entry->key;
nir_foreach_instr_reverse(instr, block) {
nir_intrinsic_instr *intrin = as_set_vertex_and_primitive_count(instr);
if (!intrin)
continue;
unsigned stream = nir_intrinsic_stream_id(intrin);
if (stream >= num_streams)
continue;
int vtxcnt = -1;
int prmcnt = -1;
/* If the number of vertices/primitives is compile-time known, we use that,
* otherwise we leave it at -1 which means that it's unknown.
*/
if (nir_src_is_const(intrin->src[0]))
vtxcnt = nir_src_as_int(intrin->src[0]);
if (nir_src_is_const(intrin->src[1]))
prmcnt = nir_src_as_int(intrin->src[1]);
/* We've found contradictory set_vertex_and_primitive_count intrinsics.
* This can happen if there are early-returns in main() and
* different paths emit different numbers of vertices.
*/
if (cnt_found[stream] && vtxcnt != vtxcnt_arr[stream])
vtxcnt = -1;
if (cnt_found[stream] && prmcnt != prmcnt_arr[stream])
prmcnt = -1;
vtxcnt_arr[stream] = vtxcnt;
prmcnt_arr[stream] = prmcnt;
cnt_found[stream] = true;
}
}
}
if (out_vtxcnt)
memcpy(out_vtxcnt, vtxcnt_arr, num_streams * sizeof(int));
if (out_prmcnt)
memcpy(out_prmcnt, prmcnt_arr, num_streams * sizeof(int));
}