mesa/src/microsoft/compiler/dxil_nir_tess.c

390 lines
15 KiB
C
Raw Permalink Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/*
* Copyright © Microsoft 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"
#include "nir_control_flow.h"
#include "dxil_nir.h"
static void
remove_hs_intrinsics(nir_function_impl *impl)
{
nir_foreach_block(block, impl) {
nir_foreach_instr_safe(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
if (intr->intrinsic != nir_intrinsic_store_output &&
intr->intrinsic != nir_intrinsic_memory_barrier_tcs_patch &&
intr->intrinsic != nir_intrinsic_control_barrier)
continue;
nir_instr_remove(instr);
}
}
nir_metadata_preserve(impl, nir_metadata_block_index | nir_metadata_dominance);
}
static void
add_instr_and_srcs_to_set(struct set *instr_set, nir_instr *instr);
static bool
add_srcs_to_set(nir_src *src, void *state)
{
assert(src->is_ssa);
add_instr_and_srcs_to_set(state, src->ssa->parent_instr);
return true;
}
static void
add_instr_and_srcs_to_set(struct set *instr_set, nir_instr *instr)
{
bool was_already_found = false;
_mesa_set_search_or_add(instr_set, instr, &was_already_found);
if (!was_already_found)
nir_foreach_src(instr, add_srcs_to_set, instr_set);
}
static void
prune_patch_function_to_intrinsic_and_srcs(nir_function_impl *impl)
{
struct set *instr_set = _mesa_pointer_set_create(NULL);
/* Do this in two phases:
* 1. Find all instructions that contribute to a store_output and add them to
* the set. Also, add instructions that contribute to control flow.
* 2. Erase every instruction that isn't in the set
*/
nir_foreach_block(block, impl) {
nir_if *following_if = nir_block_get_following_if(block);
if (following_if) {
assert(following_if->condition.is_ssa);
add_instr_and_srcs_to_set(instr_set, following_if->condition.ssa->parent_instr);
}
nir_foreach_instr_safe(instr, block) {
if (instr->type == nir_instr_type_intrinsic) {
nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
if (intr->intrinsic != nir_intrinsic_store_output &&
intr->intrinsic != nir_intrinsic_memory_barrier_tcs_patch)
continue;
} else if (instr->type != nir_instr_type_jump)
continue;
add_instr_and_srcs_to_set(instr_set, instr);
}
}
nir_foreach_block_reverse(block, impl) {
nir_foreach_instr_reverse_safe(instr, block) {
struct set_entry *entry = _mesa_set_search(instr_set, instr);
if (!entry)
nir_instr_remove(instr);
}
}
_mesa_set_destroy(instr_set, NULL);
}
static nir_cursor
get_cursor_for_instr_without_cf(nir_instr *instr)
{
nir_block *block = instr->block;
if (block->cf_node.parent->type == nir_cf_node_function)
return nir_before_instr(instr);
do {
block = nir_cf_node_as_block(nir_cf_node_prev(block->cf_node.parent));
} while (block->cf_node.parent->type != nir_cf_node_function);
return nir_after_block_before_jump(block);
}
struct tcs_patch_loop_state {
nir_ssa_def *deref, *count;
nir_cursor begin_cursor, end_cursor, insert_cursor;
nir_loop *loop;
};
static void
start_tcs_loop(nir_builder *b, struct tcs_patch_loop_state *state, nir_deref_instr *loop_var_deref)
{
if (!loop_var_deref)
return;
nir_store_deref(b, loop_var_deref, nir_imm_int(b, 0), 1);
state->loop = nir_push_loop(b);
state->count = nir_load_deref(b, loop_var_deref);
nir_push_if(b, nir_ige(b, state->count, nir_imm_int(b, b->impl->function->shader->info.tess.tcs_vertices_out)));
nir_jump(b, nir_jump_break);
nir_pop_if(b, NULL);
state->insert_cursor = b->cursor;
nir_store_deref(b, loop_var_deref, nir_iadd_imm(b, state->count, 1), 1);
nir_pop_loop(b, state->loop);
}
static void
end_tcs_loop(nir_builder *b, struct tcs_patch_loop_state *state)
{
if (!state->loop)
return;
nir_cf_list extracted;
nir_cf_extract(&extracted, state->begin_cursor, state->end_cursor);
nir_cf_reinsert(&extracted, state->insert_cursor);
*state = (struct tcs_patch_loop_state ){ 0 };
}
/* In HLSL/DXIL, the hull (tesselation control) shader is split into two:
* 1. The main hull shader, which runs once per output control point.
* 2. A patch constant function, which runs once overall.
* In GLSL/NIR, these are combined. Each invocation must write to the output
* array with a constant gl_InvocationID, which is (apparently) lowered to an
* if/else ladder in nir. Each invocation must write the same value to patch
* constants - or else undefined behavior strikes. NIR uses store_output to
* write the patch constants, and store_per_vertex_output to write the control
* point values.
*
* We clone the NIR function to produce 2: one with the store_output intrinsics
* removed, which becomes the main shader (only writes control points), and one
* with everything that doesn't contribute to store_output removed, which becomes
* the patch constant function.
*
* For the patch constant function, if the expressions rely on gl_InvocationID,
* then we need to run the resulting logic in a loop, using the loop counter to
* replace gl_InvocationID. This loop can be terminated when a barrier is hit. If
* gl_InvocationID is used again after the barrier, then another loop needs to begin.
*/
void
dxil_nir_split_tess_ctrl(nir_shader *nir, nir_function **patch_const_func)
{
assert(nir->info.stage == MESA_SHADER_TESS_CTRL);
assert(exec_list_length(&nir->functions) == 1);
nir_function_impl *entrypoint = nir_shader_get_entrypoint(nir);
*patch_const_func = nir_function_create(nir, "PatchConstantFunc");
nir_function_impl *patch_const_func_impl = nir_function_impl_clone(nir, entrypoint);
(*patch_const_func)->impl = patch_const_func_impl;
patch_const_func_impl->function = *patch_const_func;
remove_hs_intrinsics(entrypoint);
prune_patch_function_to_intrinsic_and_srcs(patch_const_func_impl);
/* Kill dead references to the invocation ID from the patch const func so we don't
* insert unnecessarily loops
*/
bool progress;
do {
progress = false;
progress |= nir_opt_dead_cf(nir);
progress |= nir_opt_dce(nir);
} while (progress);
/* Now, the patch constant function needs to be split into blocks and loops.
* The series of instructions up to the first block containing a load_invocation_id
* will run sequentially. Then a loop is inserted so load_invocation_id will load the
* loop counter. This loop continues until a barrier is reached, when the loop
* is closed and the process begins again.
*
* First, sink load_invocation_id so that it's present on both sides of barriers.
* Each use gets a unique load of the invocation ID.
*/
nir_builder b;
nir_builder_init(&b, patch_const_func_impl);
nir_foreach_block(block, patch_const_func_impl) {
nir_foreach_instr_safe(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
if (intr->intrinsic != nir_intrinsic_load_invocation_id ||
list_length(&intr->dest.ssa.uses) +
list_length(&intr->dest.ssa.if_uses) <= 1)
continue;
nir_foreach_use_safe(src, &intr->dest.ssa) {
b.cursor = nir_before_src(src, false);
nir_instr_rewrite_src_ssa(src->parent_instr, src, nir_load_invocation_id(&b));
}
nir_foreach_if_use_safe(src, &intr->dest.ssa) {
b.cursor = nir_before_src(src, true);
nir_if_rewrite_condition_ssa(src->parent_if, src, nir_load_invocation_id(&b));
}
nir_instr_remove(instr);
}
}
/* Now replace those invocation ID loads with loads of a local variable that's used as a loop counter */
nir_variable *loop_var = NULL;
nir_deref_instr *loop_var_deref = NULL;
struct tcs_patch_loop_state state = { 0 };
nir_foreach_block_safe(block, patch_const_func_impl) {
nir_foreach_instr_safe(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
switch (intr->intrinsic) {
case nir_intrinsic_load_invocation_id: {
if (!loop_var) {
loop_var = nir_local_variable_create(patch_const_func_impl, glsl_int_type(), "PatchConstInvocId");
b.cursor = nir_before_cf_list(&patch_const_func_impl->body);
loop_var_deref = nir_build_deref_var(&b, loop_var);
}
if (!state.loop) {
b.cursor = state.begin_cursor = get_cursor_for_instr_without_cf(instr);
start_tcs_loop(&b, &state, loop_var_deref);
}
nir_ssa_def_rewrite_uses(&intr->dest.ssa, state.count);
break;
}
case nir_intrinsic_memory_barrier_tcs_patch:
/* The GL tessellation spec says:
* The barrier() function may only be called inside the main entry point of the tessellation control shader
* and may not be called in potentially divergent flow control. In particular, barrier() may not be called
* inside a switch statement, in either sub-statement of an if statement, inside a do, for, or while loop,
* or at any point after a return statement in the function main().
*
* Therefore, we should be at function-level control flow.
*/
assert(nir_cursors_equal(nir_before_instr(instr), get_cursor_for_instr_without_cf(instr)));
state.end_cursor = nir_before_instr(instr);
end_tcs_loop(&b, &state);
nir_instr_remove(instr);
break;
default:
break;
}
}
}
state.end_cursor = nir_after_block_before_jump(nir_impl_last_block(patch_const_func_impl));
end_tcs_loop(&b, &state);
}
struct remove_tess_level_accesses_data {
unsigned location;
unsigned size;
};
static bool
remove_tess_level_accesses(nir_builder *b, nir_instr *instr, void *_data)
{
struct remove_tess_level_accesses_data *data = _data;
if (instr->type != nir_instr_type_intrinsic)
return false;
nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
if (intr->intrinsic != nir_intrinsic_store_output &&
intr->intrinsic != nir_intrinsic_load_input)
return false;
nir_io_semantics io = nir_intrinsic_io_semantics(intr);
if (io.location != data->location)
return false;
if (nir_intrinsic_component(intr) < data->size)
return false;
if (intr->intrinsic == nir_intrinsic_store_output) {
assert(intr->src[0].is_ssa && intr->src[0].ssa->num_components == 1);
nir_instr_remove(instr);
} else {
b->cursor = nir_after_instr(instr);
assert(intr->dest.is_ssa && intr->dest.ssa.num_components == 1);
nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_ssa_undef(b, 1, intr->dest.ssa.bit_size));
}
return true;
}
/* Update the types of the tess level variables and remove writes to removed components.
* GL always has a 4-component outer tess level and 2-component inner, while D3D requires
* the number of components to vary based on the primitive mode.
* The 4 and 2 is for quads, while triangles are 3 and 1, and lines are 2 and 0.
*/
bool
dxil_nir_fixup_tess_level_for_domain(nir_shader *nir)
{
bool progress = false;
if (nir->info.tess._primitive_mode != TESS_PRIMITIVE_QUADS) {
nir_foreach_variable_with_modes_safe(var, nir, nir_var_shader_out | nir_var_shader_in) {
unsigned new_array_size = 4;
unsigned old_array_size = glsl_array_size(var->type);
if (var->data.location == VARYING_SLOT_TESS_LEVEL_OUTER) {
new_array_size = nir->info.tess._primitive_mode == TESS_PRIMITIVE_TRIANGLES ? 3 : 2;
assert(var->data.compact && (old_array_size == 4 || old_array_size == new_array_size));
} else if (var->data.location == VARYING_SLOT_TESS_LEVEL_INNER) {
new_array_size = nir->info.tess._primitive_mode == TESS_PRIMITIVE_TRIANGLES ? 1 : 0;
assert(var->data.compact && (old_array_size == 2 || old_array_size == new_array_size));
} else
continue;
if (new_array_size == old_array_size)
continue;
progress = true;
if (new_array_size)
var->type = glsl_array_type(glsl_float_type(), new_array_size, 0);
else {
exec_node_remove(&var->node);
ralloc_free(var);
}
struct remove_tess_level_accesses_data pass_data = {
.location = var->data.location,
.size = new_array_size
};
nir_shader_instructions_pass(nir, remove_tess_level_accesses,
nir_metadata_block_index | nir_metadata_dominance, &pass_data);
}
}
return progress;
}
static bool
tcs_update_deref_input_types(nir_builder *b, nir_instr *instr, void *data)
{
if (instr->type != nir_instr_type_deref)
return false;
nir_deref_instr *deref = nir_instr_as_deref(instr);
if (deref->deref_type != nir_deref_type_var)
return false;
nir_variable *var = deref->var;
deref->type = var->type;
return true;
}
bool
dxil_nir_set_tcs_patches_in(nir_shader *nir, unsigned num_control_points)
{
bool progress = false;
nir_foreach_variable_with_modes(var, nir, nir_var_shader_in) {
if (nir_is_arrayed_io(var, MESA_SHADER_TESS_CTRL)) {
var->type = glsl_array_type(glsl_get_array_element(var->type), num_control_points, 0);
progress = true;
}
}
if (progress)
nir_shader_instructions_pass(nir, tcs_update_deref_input_types, nir_metadata_all, NULL);
return progress;
}