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b155f74d7bfc9daec7794074c4f644025fbddf8b
mesa/src/compiler/nir/nir_linking_helpers.c
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Timothy Arceri b155f74d7b nir: fix nir_remove_unused_varyings() 
We were only setting the used mask for the first component of a
varying. Since the linking opts split vectors into scalars this
has mostly worked ok.

However this causes an issue where for example if we split a
struct on one side of the interface but not the other, then we
can possibly end up removing the first components on the side
that was split and then incorrectly remove the whole struct
on the other side of the varying.

With this change we simply mark all 4 components for each slot
used by a struct. We could possibly make this more fine gained
but that would require a more complex change.

This fixes a bug in Strange Brigade on RADV when tessellation
is enabled, all credit goes to Samuel Pitoiset for tracking down
the cause of the bug.

Fixes: f1eb5e6399 ("nir: add component level support to remove_unused_io_vars()")

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
2019-04-25 16:37:36 +10:00

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/*
* 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"
#include "util/set.h"
#include "util/hash_table.h"
/* This file contains various little helpers for doing simple linking in
* NIR. Eventually, we'll probably want a full-blown varying packing
* implementation in here. Right now, it just deletes unused things.
*/
/**
* Returns the bits in the inputs_read, outputs_written, or
* system_values_read bitfield corresponding to this variable.
*/
static uint64_t
get_variable_io_mask(nir_variable *var, gl_shader_stage stage)
{
if (var->data.location < 0)
return 0;
unsigned location = var->data.patch ?
var->data.location - VARYING_SLOT_PATCH0 : var->data.location;
assert(var->data.mode == nir_var_shader_in ||
var->data.mode == nir_var_shader_out ||
var->data.mode == nir_var_system_value);
assert(var->data.location >= 0);
const struct glsl_type *type = var->type;
if (nir_is_per_vertex_io(var, stage)) {
assert(glsl_type_is_array(type));
type = glsl_get_array_element(type);
}
unsigned slots = glsl_count_attribute_slots(type, false);
return ((1ull << slots) - 1) << location;
}
static uint8_t
get_num_components(nir_variable *var)
{
if (glsl_type_is_struct_or_ifc(glsl_without_array(var->type)))
return 4;
return glsl_get_vector_elements(glsl_without_array(var->type));
}
static void
tcs_add_output_reads(nir_shader *shader, uint64_t *read, uint64_t *patches_read)
{
nir_foreach_function(function, shader) {
if (!function->impl)
continue;
nir_foreach_block(block, function->impl) {
nir_foreach_instr(instr, block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
if (intrin->intrinsic != nir_intrinsic_load_deref)
continue;
nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
if (deref->mode != nir_var_shader_out)
continue;
nir_variable *var = nir_deref_instr_get_variable(deref);
for (unsigned i = 0; i < get_num_components(var); i++) {
if (var->data.patch) {
patches_read[var->data.location_frac + i] |=
get_variable_io_mask(var, shader->info.stage);
} else {
read[var->data.location_frac + i] |=
get_variable_io_mask(var, shader->info.stage);
}
}
}
}
}
}
/**
* Helper for removing unused shader I/O variables, by demoting them to global
* variables (which may then by dead code eliminated).
*
* Example usage is:
*
* progress = nir_remove_unused_io_vars(producer,
* &producer->outputs,
* read, patches_read) ||
* progress;
*
* The "used" should be an array of 4 uint64_ts (probably of VARYING_BIT_*)
* representing each .location_frac used. Note that for vector variables,
* only the first channel (.location_frac) is examined for deciding if the
* variable is used!
*/
bool
nir_remove_unused_io_vars(nir_shader *shader, struct exec_list *var_list,
uint64_t *used_by_other_stage,
uint64_t *used_by_other_stage_patches)
{
bool progress = false;
uint64_t *used;
nir_foreach_variable_safe(var, var_list) {
if (var->data.patch)
used = used_by_other_stage_patches;
else
used = used_by_other_stage;
if (var->data.location < VARYING_SLOT_VAR0 && var->data.location >= 0)
continue;
if (var->data.always_active_io)
continue;
if (var->data.explicit_xfb_buffer)
continue;
uint64_t other_stage = used[var->data.location_frac];
if (!(other_stage & get_variable_io_mask(var, shader->info.stage))) {
/* This one is invalid, make it a global variable instead */
var->data.location = 0;
var->data.mode = nir_var_shader_temp;
exec_node_remove(&var->node);
exec_list_push_tail(&shader->globals, &var->node);
progress = true;
}
}
if (progress)
nir_fixup_deref_modes(shader);
return progress;
}
bool
nir_remove_unused_varyings(nir_shader *producer, nir_shader *consumer)
{
assert(producer->info.stage != MESA_SHADER_FRAGMENT);
assert(consumer->info.stage != MESA_SHADER_VERTEX);
uint64_t read[4] = { 0 }, written[4] = { 0 };
uint64_t patches_read[4] = { 0 }, patches_written[4] = { 0 };
nir_foreach_variable(var, &producer->outputs) {
for (unsigned i = 0; i < get_num_components(var); i++) {
if (var->data.patch) {
patches_written[var->data.location_frac + i] |=
get_variable_io_mask(var, producer->info.stage);
} else {
written[var->data.location_frac + i] |=
get_variable_io_mask(var, producer->info.stage);
}
}
}
nir_foreach_variable(var, &consumer->inputs) {
for (unsigned i = 0; i < get_num_components(var); i++) {
if (var->data.patch) {
patches_read[var->data.location_frac + i] |=
get_variable_io_mask(var, consumer->info.stage);
} else {
read[var->data.location_frac + i] |=
get_variable_io_mask(var, consumer->info.stage);
}
}
}
/* Each TCS invocation can read data written by other TCS invocations,
* so even if the outputs are not used by the TES we must also make
* sure they are not read by the TCS before demoting them to globals.
*/
if (producer->info.stage == MESA_SHADER_TESS_CTRL)
tcs_add_output_reads(producer, read, patches_read);
bool progress = false;
progress = nir_remove_unused_io_vars(producer, &producer->outputs, read,
patches_read);
progress = nir_remove_unused_io_vars(consumer, &consumer->inputs, written,
patches_written) || progress;
return progress;
}
static uint8_t
get_interp_type(nir_variable *var, const struct glsl_type *type,
bool default_to_smooth_interp)
{
if (glsl_type_is_integer(type))
return INTERP_MODE_FLAT;
else if (var->data.interpolation != INTERP_MODE_NONE)
return var->data.interpolation;
else if (default_to_smooth_interp)
return INTERP_MODE_SMOOTH;
else
return INTERP_MODE_NONE;
}
#define INTERPOLATE_LOC_SAMPLE 0
#define INTERPOLATE_LOC_CENTROID 1
#define INTERPOLATE_LOC_CENTER 2
static uint8_t
get_interp_loc(nir_variable *var)
{
if (var->data.sample)
return INTERPOLATE_LOC_SAMPLE;
else if (var->data.centroid)
return INTERPOLATE_LOC_CENTROID;
else
return INTERPOLATE_LOC_CENTER;
}
static bool
is_packing_supported_for_type(const struct glsl_type *type)
{
/* We ignore complex types such as arrays, matrices, structs and bitsizes
* other then 32bit. All other vector types should have been split into
* scalar variables by the lower_io_to_scalar pass. The only exception
* should be OpenGL xfb varyings.
* TODO: add support for more complex types?
*/
return glsl_type_is_scalar(type) && glsl_type_is_32bit(type);
}
struct assigned_comps
{
uint8_t comps;
uint8_t interp_type;
uint8_t interp_loc;
bool is_32bit;
};
/* Packing arrays and dual slot varyings is difficult so to avoid complex
* algorithms this function just assigns them their existing location for now.
* TODO: allow better packing of complex types.
*/
static void
get_unmoveable_components_masks(struct exec_list *var_list,
struct assigned_comps *comps,
gl_shader_stage stage,
bool default_to_smooth_interp)
{
nir_foreach_variable_safe(var, var_list) {
assert(var->data.location >= 0);
/* Only remap things that aren't built-ins. */
if (var->data.location >= VARYING_SLOT_VAR0 &&
var->data.location - VARYING_SLOT_VAR0 < MAX_VARYINGS_INCL_PATCH) {
const struct glsl_type *type = var->type;
if (nir_is_per_vertex_io(var, stage)) {
assert(glsl_type_is_array(type));
type = glsl_get_array_element(type);
}
/* If we can pack this varying then don't mark the components as
* used.
*/
if (is_packing_supported_for_type(type))
continue;
unsigned location = var->data.location - VARYING_SLOT_VAR0;
unsigned elements =
glsl_type_is_vector_or_scalar(glsl_without_array(type)) ?
glsl_get_vector_elements(glsl_without_array(type)) : 4;
bool dual_slot = glsl_type_is_dual_slot(glsl_without_array(type));
unsigned slots = glsl_count_attribute_slots(type, false);
unsigned dmul = glsl_type_is_64bit(glsl_without_array(type)) ? 2 : 1;
unsigned comps_slot2 = 0;
for (unsigned i = 0; i < slots; i++) {
if (dual_slot) {
if (i & 1) {
comps[location + i].comps |= ((1 << comps_slot2) - 1);
} else {
unsigned num_comps = 4 - var->data.location_frac;
comps_slot2 = (elements * dmul) - num_comps;
/* Assume ARB_enhanced_layouts packing rules for doubles */
assert(var->data.location_frac == 0 ||
var->data.location_frac == 2);
assert(comps_slot2 <= 4);
comps[location + i].comps |=
((1 << num_comps) - 1) << var->data.location_frac;
}
} else {
comps[location + i].comps |=
((1 << (elements * dmul)) - 1) << var->data.location_frac;
}
comps[location + i].interp_type =
get_interp_type(var, type, default_to_smooth_interp);
comps[location + i].interp_loc = get_interp_loc(var);
comps[location + i].is_32bit =
glsl_type_is_32bit(glsl_without_array(type));
}
}
}
}
struct varying_loc
{
uint8_t component;
uint32_t location;
};
static void
mark_all_used_slots(nir_variable *var, uint64_t *slots_used,
uint64_t slots_used_mask, unsigned num_slots)
{
unsigned loc_offset = var->data.patch ? VARYING_SLOT_PATCH0 : 0;
slots_used[var->data.patch ? 1 : 0] |= slots_used_mask &
BITFIELD64_RANGE(var->data.location - loc_offset, num_slots);
}
static void
mark_used_slot(nir_variable *var, uint64_t *slots_used, unsigned offset)
{
unsigned loc_offset = var->data.patch ? VARYING_SLOT_PATCH0 : 0;
slots_used[var->data.patch ? 1 : 0] |=
BITFIELD64_BIT(var->data.location - loc_offset + offset);
}
static void
remap_slots_and_components(struct exec_list *var_list, gl_shader_stage stage,
struct varying_loc (*remap)[4],
uint64_t *slots_used, uint64_t *out_slots_read,
uint32_t *p_slots_used, uint32_t *p_out_slots_read)
{
uint64_t out_slots_read_tmp[2] = {0};
uint64_t slots_used_tmp[2] = {0};
/* We don't touch builtins so just copy the bitmask */
slots_used_tmp[0] = *slots_used & BITFIELD64_RANGE(0, VARYING_SLOT_VAR0);
nir_foreach_variable(var, var_list) {
assert(var->data.location >= 0);
/* Only remap things that aren't built-ins */
if (var->data.location >= VARYING_SLOT_VAR0 &&
var->data.location - VARYING_SLOT_VAR0 < MAX_VARYINGS_INCL_PATCH) {
const struct glsl_type *type = var->type;
if (nir_is_per_vertex_io(var, stage)) {
assert(glsl_type_is_array(type));
type = glsl_get_array_element(type);
}
unsigned num_slots = glsl_count_attribute_slots(type, false);
bool used_across_stages = false;
bool outputs_read = false;
unsigned location = var->data.location - VARYING_SLOT_VAR0;
struct varying_loc *new_loc = &remap[location][var->data.location_frac];
unsigned loc_offset = var->data.patch ? VARYING_SLOT_PATCH0 : 0;
uint64_t used = var->data.patch ? *p_slots_used : *slots_used;
uint64_t outs_used =
var->data.patch ? *p_out_slots_read : *out_slots_read;
uint64_t slots =
BITFIELD64_RANGE(var->data.location - loc_offset, num_slots);
if (slots & used)
used_across_stages = true;
if (slots & outs_used)
outputs_read = true;
if (new_loc->location) {
var->data.location = new_loc->location;
var->data.location_frac = new_loc->component;
}
if (var->data.always_active_io) {
/* We can't apply link time optimisations (specifically array
* splitting) to these so we need to copy the existing mask
* otherwise we will mess up the mask for things like partially
* marked arrays.
*/
if (used_across_stages)
mark_all_used_slots(var, slots_used_tmp, used, num_slots);
if (outputs_read) {
mark_all_used_slots(var, out_slots_read_tmp, outs_used,
num_slots);
}
} else {
for (unsigned i = 0; i < num_slots; i++) {
if (used_across_stages)
mark_used_slot(var, slots_used_tmp, i);
if (outputs_read)
mark_used_slot(var, out_slots_read_tmp, i);
}
}
}
}
*slots_used = slots_used_tmp[0];
*out_slots_read = out_slots_read_tmp[0];
*p_slots_used = slots_used_tmp[1];
*p_out_slots_read = out_slots_read_tmp[1];
}
struct varying_component {
nir_variable *var;
uint8_t interp_type;
uint8_t interp_loc;
bool is_32bit;
bool is_patch;
bool initialised;
};
static int
cmp_varying_component(const void *comp1_v, const void *comp2_v)
{
struct varying_component *comp1 = (struct varying_component *) comp1_v;
struct varying_component *comp2 = (struct varying_component *) comp2_v;
/* We want patches to be order at the end of the array */
if (comp1->is_patch != comp2->is_patch)
return comp1->is_patch ? 1 : -1;
/* We can only pack varyings with matching interpolation types so group
* them together.
*/
if (comp1->interp_type != comp2->interp_type)
return comp1->interp_type - comp2->interp_type;
/* Interpolation loc must match also. */
if (comp1->interp_loc != comp2->interp_loc)
return comp1->interp_loc - comp2->interp_loc;
/* If everything else matches just use the original location to sort */
return comp1->var->data.location - comp2->var->data.location;
}
static void
gather_varying_component_info(nir_shader *consumer,
struct varying_component **varying_comp_info,
unsigned *varying_comp_info_size,
bool default_to_smooth_interp)
{
unsigned store_varying_info_idx[MAX_VARYINGS_INCL_PATCH][4] = {0};
unsigned num_of_comps_to_pack = 0;
/* Count the number of varying that can be packed and create a mapping
* of those varyings to the array we will pass to qsort.
*/
nir_foreach_variable(var, &consumer->inputs) {
/* Only remap things that aren't builtins. */
if (var->data.location >= VARYING_SLOT_VAR0 &&
var->data.location - VARYING_SLOT_VAR0 < MAX_VARYINGS_INCL_PATCH) {
/* We can't repack xfb varyings. */
if (var->data.always_active_io)
continue;
const struct glsl_type *type = var->type;
if (nir_is_per_vertex_io(var, consumer->info.stage)) {
assert(glsl_type_is_array(type));
type = glsl_get_array_element(type);
}
if (!is_packing_supported_for_type(type))
continue;
unsigned loc = var->data.location - VARYING_SLOT_VAR0;
store_varying_info_idx[loc][var->data.location_frac] =
++num_of_comps_to_pack;
}
}
*varying_comp_info_size = num_of_comps_to_pack;
*varying_comp_info = rzalloc_array(NULL, struct varying_component,
num_of_comps_to_pack);
nir_function_impl *impl = nir_shader_get_entrypoint(consumer);
/* Walk over the shader and populate the varying component info array */
nir_foreach_block(block, impl) {
nir_foreach_instr(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_deref &&
intr->intrinsic != nir_intrinsic_interp_deref_at_centroid &&
intr->intrinsic != nir_intrinsic_interp_deref_at_sample &&
intr->intrinsic != nir_intrinsic_interp_deref_at_offset)
continue;
nir_deref_instr *deref = nir_src_as_deref(intr->src[0]);
if (deref->mode != nir_var_shader_in)
continue;
/* We only remap things that aren't builtins. */
nir_variable *in_var = nir_deref_instr_get_variable(deref);
if (in_var->data.location < VARYING_SLOT_VAR0)
continue;
unsigned location = in_var->data.location - VARYING_SLOT_VAR0;
if (location >= MAX_VARYINGS_INCL_PATCH)
continue;
unsigned var_info_idx =
store_varying_info_idx[location][in_var->data.location_frac];
if (!var_info_idx)
continue;
struct varying_component *vc_info =
&(*varying_comp_info)[var_info_idx-1];
if (!vc_info->initialised) {
const struct glsl_type *type = in_var->type;
if (nir_is_per_vertex_io(in_var, consumer->info.stage)) {
assert(glsl_type_is_array(type));
type = glsl_get_array_element(type);
}
vc_info->var = in_var;
vc_info->interp_type =
get_interp_type(in_var, type, default_to_smooth_interp);
vc_info->interp_loc = get_interp_loc(in_var);
vc_info->is_32bit = glsl_type_is_32bit(type);
vc_info->is_patch = in_var->data.patch;
}
}
}
}
static void
assign_remap_locations(struct varying_loc (*remap)[4],
struct assigned_comps *assigned_comps,
struct varying_component *info,
unsigned *cursor, unsigned *comp,
unsigned max_location)
{
unsigned tmp_cursor = *cursor;
unsigned tmp_comp = *comp;
for (; tmp_cursor < max_location; tmp_cursor++) {
if (assigned_comps[tmp_cursor].comps) {
/* We can only pack varyings with matching interpolation types,
* interpolation loc must match also.
* TODO: i965 can handle interpolation locations that don't match,
* but the radeonsi nir backend handles everything as vec4s and so
* expects this to be the same for all components. We could make this
* check driver specfific or drop it if NIR ever become the only
* radeonsi backend.
*/
if (assigned_comps[tmp_cursor].interp_type != info->interp_type ||
assigned_comps[tmp_cursor].interp_loc != info->interp_loc) {
tmp_comp = 0;
continue;
}
/* We can only pack varyings with matching types, and the current
* algorithm only supports packing 32-bit.
*/
if (!assigned_comps[tmp_cursor].is_32bit) {
tmp_comp = 0;
continue;
}
while (tmp_comp < 4 &&
(assigned_comps[tmp_cursor].comps & (1 << tmp_comp))) {
tmp_comp++;
}
}
if (tmp_comp == 4) {
tmp_comp = 0;
continue;
}
unsigned location = info->var->data.location - VARYING_SLOT_VAR0;
/* Once we have assigned a location mark it as used */
assigned_comps[tmp_cursor].comps |= (1 << tmp_comp);
assigned_comps[tmp_cursor].interp_type = info->interp_type;
assigned_comps[tmp_cursor].interp_loc = info->interp_loc;
assigned_comps[tmp_cursor].is_32bit = info->is_32bit;
/* Assign remap location */
remap[location][info->var->data.location_frac].component = tmp_comp++;
remap[location][info->var->data.location_frac].location =
tmp_cursor + VARYING_SLOT_VAR0;
break;
}
*cursor = tmp_cursor;
*comp = tmp_comp;
}
/* If there are empty components in the slot compact the remaining components
* as close to component 0 as possible. This will make it easier to fill the
* empty components with components from a different slot in a following pass.
*/
static void
compact_components(nir_shader *producer, nir_shader *consumer,
struct assigned_comps *assigned_comps,
bool default_to_smooth_interp)
{
struct exec_list *input_list = &consumer->inputs;
struct exec_list *output_list = &producer->outputs;
struct varying_loc remap[MAX_VARYINGS_INCL_PATCH][4] = {{{0}, {0}}};
struct varying_component *varying_comp_info;
unsigned varying_comp_info_size;
/* Gather varying component info */
gather_varying_component_info(consumer, &varying_comp_info,
&varying_comp_info_size,
default_to_smooth_interp);
/* Sort varying components. */
qsort(varying_comp_info, varying_comp_info_size,
sizeof(struct varying_component), cmp_varying_component);
unsigned cursor = 0;
unsigned comp = 0;
/* Set the remap array based on the sorted components */
for (unsigned i = 0; i < varying_comp_info_size; i++ ) {
struct varying_component *info = &varying_comp_info[i];
assert(info->is_patch || cursor < MAX_VARYING);
if (info->is_patch) {
/* The list should be sorted with all non-patch inputs first followed
* by patch inputs. When we hit our first patch input, we need to
* reset the cursor to MAX_VARYING so we put them in the right slot.
*/
if (cursor < MAX_VARYING) {
cursor = MAX_VARYING;
comp = 0;
}
assign_remap_locations(remap, assigned_comps, info,
&cursor, &comp, MAX_VARYINGS_INCL_PATCH);
} else {
assign_remap_locations(remap, assigned_comps, info,
&cursor, &comp, MAX_VARYING);
/* Check if we failed to assign a remap location. This can happen if
* for example there are a bunch of unmovable components with
* mismatching interpolation types causing us to skip over locations
* that would have been useful for packing later components.
* The solution is to iterate over the locations again (this should
* happen very rarely in practice).
*/
if (cursor == MAX_VARYING) {
cursor = 0;
comp = 0;
assign_remap_locations(remap, assigned_comps, info,
&cursor, &comp, MAX_VARYING);
}
}
}
ralloc_free(varying_comp_info);
uint64_t zero = 0;
uint32_t zero32 = 0;
remap_slots_and_components(input_list, consumer->info.stage, remap,
&consumer->info.inputs_read, &zero,
&consumer->info.patch_inputs_read, &zero32);
remap_slots_and_components(output_list, producer->info.stage, remap,
&producer->info.outputs_written,
&producer->info.outputs_read,
&producer->info.patch_outputs_written,
&producer->info.patch_outputs_read);
}
/* We assume that this has been called more-or-less directly after
* remove_unused_varyings. At this point, all of the varyings that we
* aren't going to be using have been completely removed and the
* inputs_read and outputs_written fields in nir_shader_info reflect
* this. Therefore, the total set of valid slots is the OR of the two
* sets of varyings; this accounts for varyings which one side may need
* to read/write even if the other doesn't. This can happen if, for
* instance, an array is used indirectly from one side causing it to be
* unsplittable but directly from the other.
*/
void
nir_compact_varyings(nir_shader *producer, nir_shader *consumer,
bool default_to_smooth_interp)
{
assert(producer->info.stage != MESA_SHADER_FRAGMENT);
assert(consumer->info.stage != MESA_SHADER_VERTEX);
struct assigned_comps assigned_comps[MAX_VARYINGS_INCL_PATCH] = {0};
get_unmoveable_components_masks(&producer->outputs, assigned_comps,
producer->info.stage,
default_to_smooth_interp);
get_unmoveable_components_masks(&consumer->inputs, assigned_comps,
consumer->info.stage,
default_to_smooth_interp);
compact_components(producer, consumer, assigned_comps,
default_to_smooth_interp);
}
/*
* Mark XFB varyings as always_active_io in the consumer so the linking opts
* don't touch them.
*/
void
nir_link_xfb_varyings(nir_shader *producer, nir_shader *consumer)
{
nir_variable *input_vars[MAX_VARYING] = { 0 };
nir_foreach_variable(var, &consumer->inputs) {
if (var->data.location >= VARYING_SLOT_VAR0 &&
var->data.location - VARYING_SLOT_VAR0 < MAX_VARYING) {
unsigned location = var->data.location - VARYING_SLOT_VAR0;
input_vars[location] = var;
}
}
nir_foreach_variable(var, &producer->outputs) {
if (var->data.location >= VARYING_SLOT_VAR0 &&
var->data.location - VARYING_SLOT_VAR0 < MAX_VARYING) {
if (!var->data.always_active_io)
continue;
unsigned location = var->data.location - VARYING_SLOT_VAR0;
if (input_vars[location]) {
input_vars[location]->data.always_active_io = true;
}
}
}
}
static bool
does_varying_match(nir_variable *out_var, nir_variable *in_var)
{
return in_var->data.location == out_var->data.location &&
in_var->data.location_frac == out_var->data.location_frac;
}
static nir_variable *
get_matching_input_var(nir_shader *consumer, nir_variable *out_var)
{
nir_foreach_variable(var, &consumer->inputs) {
if (does_varying_match(out_var, var))
return var;
}
return NULL;
}
static bool
can_replace_varying(nir_variable *out_var)
{
/* Skip types that require more complex handling.
* TODO: add support for these types.
*/
if (glsl_type_is_array(out_var->type) ||
glsl_type_is_dual_slot(out_var->type) ||
glsl_type_is_matrix(out_var->type) ||
glsl_type_is_struct_or_ifc(out_var->type))
return false;
/* Limit this pass to scalars for now to keep things simple. Most varyings
* should have been lowered to scalars at this point anyway.
*/
if (!glsl_type_is_scalar(out_var->type))
return false;
if (out_var->data.location < VARYING_SLOT_VAR0 ||
out_var->data.location - VARYING_SLOT_VAR0 >= MAX_VARYING)
return false;
return true;
}
static bool
replace_constant_input(nir_shader *shader, nir_intrinsic_instr *store_intr)
{
nir_function_impl *impl = nir_shader_get_entrypoint(shader);
nir_builder b;
nir_builder_init(&b, impl);
nir_variable *out_var =
nir_deref_instr_get_variable(nir_src_as_deref(store_intr->src[0]));
bool progress = false;
nir_foreach_block(block, impl) {
nir_foreach_instr(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_deref)
continue;
nir_deref_instr *in_deref = nir_src_as_deref(intr->src[0]);
if (in_deref->mode != nir_var_shader_in)
continue;
nir_variable *in_var = nir_deref_instr_get_variable(in_deref);
if (!does_varying_match(out_var, in_var))
continue;
b.cursor = nir_before_instr(instr);
nir_load_const_instr *out_const =
nir_instr_as_load_const(store_intr->src[1].ssa->parent_instr);
/* Add new const to replace the input */
nir_ssa_def *nconst = nir_build_imm(&b, store_intr->num_components,
intr->dest.ssa.bit_size,
out_const->value);
nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(nconst));
progress = true;
}
}
return progress;
}
static bool
replace_duplicate_input(nir_shader *shader, nir_variable *input_var,
nir_intrinsic_instr *dup_store_intr)
{
assert(input_var);
nir_function_impl *impl = nir_shader_get_entrypoint(shader);
nir_builder b;
nir_builder_init(&b, impl);
nir_variable *dup_out_var =
nir_deref_instr_get_variable(nir_src_as_deref(dup_store_intr->src[0]));
bool progress = false;
nir_foreach_block(block, impl) {
nir_foreach_instr(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_deref)
continue;
nir_deref_instr *in_deref = nir_src_as_deref(intr->src[0]);
if (in_deref->mode != nir_var_shader_in)
continue;
nir_variable *in_var = nir_deref_instr_get_variable(in_deref);
if (!does_varying_match(dup_out_var, in_var) ||
in_var->data.interpolation != input_var->data.interpolation ||
get_interp_loc(in_var) != get_interp_loc(input_var))
continue;
b.cursor = nir_before_instr(instr);
nir_ssa_def *load = nir_load_var(&b, input_var);
nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(load));
progress = true;
}
}
return progress;
}
bool
nir_link_opt_varyings(nir_shader *producer, nir_shader *consumer)
{
/* TODO: Add support for more shader stage combinations */
if (consumer->info.stage != MESA_SHADER_FRAGMENT ||
(producer->info.stage != MESA_SHADER_VERTEX &&
producer->info.stage != MESA_SHADER_TESS_EVAL))
return false;
bool progress = false;
nir_function_impl *impl = nir_shader_get_entrypoint(producer);
struct hash_table *varying_values = _mesa_pointer_hash_table_create(NULL);
/* If we find a store in the last block of the producer we can be sure this
* is the only possible value for this output.
*/
nir_block *last_block = nir_impl_last_block(impl);
nir_foreach_instr_reverse(instr, last_block) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
if (intr->intrinsic != nir_intrinsic_store_deref)
continue;
nir_deref_instr *out_deref = nir_src_as_deref(intr->src[0]);
if (out_deref->mode != nir_var_shader_out)
continue;
nir_variable *out_var = nir_deref_instr_get_variable(out_deref);
if (!can_replace_varying(out_var))
continue;
if (intr->src[1].ssa->parent_instr->type == nir_instr_type_load_const) {
progress |= replace_constant_input(consumer, intr);
} else {
struct hash_entry *entry =
_mesa_hash_table_search(varying_values, intr->src[1].ssa);
if (entry) {
progress |= replace_duplicate_input(consumer,
(nir_variable *) entry->data,
intr);
} else {
nir_variable *in_var = get_matching_input_var(consumer, out_var);
if (in_var) {
_mesa_hash_table_insert(varying_values, intr->src[1].ssa,
in_var);
}
}
}
}
_mesa_hash_table_destroy(varying_values, NULL);
return progress;
}
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