mesa/src/compiler/nir/nir_lower_is_helper_invocat...

127 lines
4.4 KiB
C

/*
* Copyright © 2021 Igalia S.L.
*
* 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"
/* Some hardware doesn't have a way to check if invocation was demoted,
* in such case we have to track it ourselves.
* OpIsHelperInvocationEXT is specified as:
*
* "An invocation is currently a helper invocation if it was originally
* invoked as a helper invocation or if it has been demoted to a helper
* invocation by OpDemoteToHelperInvocationEXT."
*
* Therefore we:
* - Set gl_IsHelperInvocationEXT = gl_HelperInvocation
* - Add "gl_IsHelperInvocationEXT = true" right before each demote
* - Add "gl_IsHelperInvocationEXT = gl_IsHelperInvocationEXT || condition"
* right before each demote_if
*/
static bool
nir_lower_load_and_store_is_helper(nir_builder *b, nir_instr *instr, void *data)
{
if (instr->type != nir_instr_type_intrinsic)
return false;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
nir_deref_instr *is_helper_deref = (nir_deref_instr*) data;
switch (intrin->intrinsic) {
case nir_intrinsic_demote: {
b->cursor = nir_before_instr(instr);
nir_store_deref(b, is_helper_deref, nir_imm_bool(b, true), 1);
return true;
}
case nir_intrinsic_demote_if: {
b->cursor = nir_before_instr(instr);
nir_ssa_def *current_is_helper = nir_load_deref(b, is_helper_deref);
nir_ssa_def *updated_is_helper = nir_ior(b, current_is_helper, intrin->src[0].ssa);
nir_store_deref(b, is_helper_deref, updated_is_helper, 1);
return true;
}
case nir_intrinsic_is_helper_invocation: {
b->cursor = nir_before_instr(instr);
nir_ssa_def *is_helper = nir_load_deref(b, is_helper_deref);
nir_ssa_def_rewrite_uses(&intrin->dest.ssa, is_helper);
nir_instr_remove_v(instr);
return true;
}
default:
return false;
}
}
static bool
has_is_helper_invocation(nir_shader *shader)
{
nir_foreach_function(function, shader) {
if (!function->impl)
continue;
nir_foreach_block_safe(block, function->impl) {
nir_foreach_instr_safe(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
if (intrin->intrinsic == nir_intrinsic_is_helper_invocation)
return true;
}
}
}
return false;
}
bool
nir_lower_is_helper_invocation(nir_shader *shader)
{
if (shader->info.stage != MESA_SHADER_FRAGMENT)
return false;
if (!has_is_helper_invocation(shader))
return false;
nir_function_impl *entrypoint = nir_shader_get_entrypoint(shader);
nir_builder b;
nir_builder_init(&b, entrypoint);
b.cursor = nir_before_cf_list(&entrypoint->body);
nir_variable *is_helper = nir_local_variable_create(entrypoint,
glsl_bool_type(),
"gl_IsHelperInvocationEXT");
nir_ssa_def *started_as_helper = nir_load_helper_invocation(&b, 1);
nir_deref_instr *is_helper_deref = nir_build_deref_var(&b, is_helper);
nir_store_deref(&b, is_helper_deref, started_as_helper, 1);
return nir_shader_instructions_pass(shader,
nir_lower_load_and_store_is_helper,
nir_metadata_all,
is_helper_deref);
}