[Mesa-dev] [PATCH 15/16] mesa/st: add nir pass for lowering builtin uniforms
Jason Ekstrand
jason at jlekstrand.net
Fri Apr 1 18:23:34 UTC 2016
On Sat, Mar 26, 2016 at 2:02 PM, Rob Clark <robdclark at gmail.com> wrote:
> From: Rob Clark <robclark at freedesktop.org>
>
> Signed-off-by: Rob Clark <robclark at freedesktop.org>
> ---
> src/mesa/Makefile.sources | 2 +
> src/mesa/state_tracker/st_nir.h | 28 +++
> src/mesa/state_tracker/st_nir_lower_builtin.c | 242
> ++++++++++++++++++++++++++
> 3 files changed, 272 insertions(+)
> create mode 100644 src/mesa/state_tracker/st_nir.h
> create mode 100644 src/mesa/state_tracker/st_nir_lower_builtin.c
>
> diff --git a/src/mesa/Makefile.sources b/src/mesa/Makefile.sources
> index 7b5b6ea..6c93d07 100644
> --- a/src/mesa/Makefile.sources
> +++ b/src/mesa/Makefile.sources
> @@ -495,6 +495,8 @@ STATETRACKER_FILES = \
> state_tracker/st_manager.h \
> state_tracker/st_mesa_to_tgsi.c \
> state_tracker/st_mesa_to_tgsi.h \
> + state_tracker/st_nir.h \
> + state_tracker/st_nir_lower_builtin.c \
> state_tracker/st_program.c \
> state_tracker/st_program.h \
> state_tracker/st_texture.c \
> diff --git a/src/mesa/state_tracker/st_nir.h
> b/src/mesa/state_tracker/st_nir.h
> new file mode 100644
> index 0000000..1c07c4c
> --- /dev/null
> +++ b/src/mesa/state_tracker/st_nir.h
> @@ -0,0 +1,28 @@
> +/*
> + * Copyright © 2016 Red Hat
> + *
> + * 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.
> + */
> +
> +#pragma once
> +
> +typedef struct nir_shader nir_shader;
> +
> +void st_nir_lower_builtin(nir_shader *shader);
> diff --git a/src/mesa/state_tracker/st_nir_lower_builtin.c
> b/src/mesa/state_tracker/st_nir_lower_builtin.c
> new file mode 100644
> index 0000000..7f3262f
> --- /dev/null
> +++ b/src/mesa/state_tracker/st_nir_lower_builtin.c
> @@ -0,0 +1,242 @@
> +/*
> + * Copyright © 2016 Red Hat
> + *
> + * 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.
> + */
> +
> +/* Lowering pass that lowers accesses to built-in uniform variables.
> + * Built-in uniforms are not necessarily packed the same way that
> + * normal uniform structs are, for example:
> + *
> + * struct gl_FogParameters {
> + * vec4 color;
> + * float density;
> + * float start;
> + * float end;
> + * float scale;
> + * };
> + *
> + * is packed into vec4[2], whereas the same struct would be packed
> + * (by gallium), as vec4[5] if it where not built-in. Because of
> + * this, we need to replace (for example) access like:
> + *
> + * vec1 ssa_1 = intrinsic load_var () (gl_Fog.start) ()
> + *
> + * with:
> + *
> + * vec4 ssa_2 = intrinsic load_var () (fog.params) ()
> + * vec1 ssa_1 = ssa_2.y
> + *
> + * with appropriate substitutions in the uniform variables list:
> + *
> + * decl_var uniform INTERP_QUALIFIER_NONE gl_FogParameters gl_Fog (0,
> 0)
> + *
> + * would become:
> + *
> + * decl_var uniform INTERP_QUALIFIER_NONE vec4 state.fog.color (0, 0)
> + * decl_var uniform INTERP_QUALIFIER_NONE vec4 state.fog.params (0, 1)
> + *
> + * See in particular 'struct gl_builtin_uniform_element'.
> + */
> +
> +#include "compiler/nir/nir.h"
> +#include "compiler/nir/nir_builder.h"
> +#include "st_nir.h"
> +#include "compiler/glsl/ir.h"
> +#include "uniforms.h"
> +#include "program/prog_instruction.h"
> +
> +typedef struct {
> + nir_shader *shader;
> + nir_builder builder;
> + void *mem_ctx;
> +} lower_builtin_state;
> +
> +static const struct gl_builtin_uniform_element *
> +get_element(const struct gl_builtin_uniform_desc *desc, nir_deref_var
> *deref)
> +{
> + nir_deref *tail = &deref->deref;
> +
> + if ((desc->num_elements == 1) && (desc->elements[0].field == NULL))
> + return NULL;
> +
> + /* we handle array's in get_variable(): */
> + if (tail->child->deref_type == nir_deref_type_array)
> + tail = tail->child;
> +
> + /* don't need to deal w/ non-struct or array of non-struct: */
> + if (!tail->child)
> + return NULL;
> +
> + if (tail->child->deref_type != nir_deref_type_struct)
> + return NULL;
> +
> + nir_deref_struct *deref_struct = nir_deref_as_struct(tail->child);
> +
> + assert(deref_struct->index < desc->num_elements);
> +
> + return &desc->elements[deref_struct->index];
> +}
> +
> +static nir_variable *
> +get_variable(lower_builtin_state *state, nir_deref_var *deref,
> + const struct gl_builtin_uniform_element *element)
> +{
> + nir_shader *shader = state->shader;
> + int tokens[STATE_LENGTH];
> +
> + memcpy(tokens, element->tokens, sizeof(tokens));
> +
> + if (deref->deref.child->deref_type == nir_deref_type_array) {
> + nir_deref_array *darr = nir_deref_as_array(deref->deref.child);
> +
> + assert(darr->deref_array_type == nir_deref_array_type_direct);
> +
> + /* we need to fixup the array index slot: */
> + switch (tokens[0]) {
> + case STATE_MODELVIEW_MATRIX:
> + case STATE_PROJECTION_MATRIX:
> + case STATE_MVP_MATRIX:
> + case STATE_TEXTURE_MATRIX:
> + case STATE_PROGRAM_MATRIX:
> + case STATE_LIGHT:
> + case STATE_LIGHTPROD:
> + case STATE_TEXGEN:
> + case STATE_TEXENV_COLOR:
> + case STATE_CLIPPLANE:
> + tokens[1] = darr->base_offset;
> + break;
> + }
> + }
> +
> + char *name = _mesa_program_state_string((gl_state_index *)tokens);
> +
> + nir_foreach_variable(var, &shader->uniforms)
> + if (strcmp(var->name, name) == 0)
> + return var;
> +
> + /* variable doesn't exist yet, so create it: */
> + nir_variable *var =
> + nir_variable_create(shader, nir_var_uniform, glsl_vec4_type(),
> name);
> +
> + var->num_state_slots = 1;
> + var->state_slots = ralloc_array(var, nir_state_slot, 1);
> + memcpy(var->state_slots[0].tokens, tokens,
> + sizeof(var->state_slots[0].tokens));
> +
> + free(name);
> +
> + return var;
> +}
> +
> +static bool
> +lower_builtin_block(nir_block *block, void *_state)
> +{
> + lower_builtin_state *state = _state;
> +
> + nir_builder *b = &state->builder;
> +
> + nir_foreach_instr_safe(block, instr) {
> + if (instr->type != nir_instr_type_intrinsic)
> + continue;
> +
> + nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
> +
> + if (intrin->intrinsic != nir_intrinsic_load_var)
> + continue;
> +
> + nir_variable *var = intrin->variables[0]->var;
> + if (var->data.mode != nir_var_uniform)
> + continue;
> +
> + /* built-in's will always start with "gl_" */
> + if (strncmp(var->name, "gl_", 3) != 0)
> + continue;
> +
> + const struct gl_builtin_uniform_desc *desc =
> + _mesa_glsl_get_builtin_uniform_desc(var->name);
> +
> + /* if no descriptor, it isn't something we need to handle
> specially: */
> + if (!desc)
> + continue;
> +
> + const struct gl_builtin_uniform_element *element =
> + get_element(desc, intrin->variables[0]);
> +
> + /* matrix elements (array_deref) do not need special handling: */
> + if (!element)
> + continue;
> +
> + /* remove existing var from uniform list: */
> + exec_node_remove(&var->node);
> + exec_node_self_link(&var->node); /* no delinit() :-( */
>
Are you sure you want to remove it multiple times? There can be more than
one load_var for a particular uniform. I guess since you self_link, it's
safe to do so. Maybe throw in a comment?
Other than that, this looks mostly ok to me. I can't really say that I
know enough to properly review it though.
> +
> + nir_variable *new_var =
> + get_variable(state, intrin->variables[0], element);
> +
> + b->cursor = nir_before_instr(instr);
> +
> + nir_ssa_def *def = nir_load_var(b, new_var);
> +
> + /* swizzle the result: */
> + unsigned swiz[4];
> + for (unsigned i = 0; i < 4; i++) {
> + swiz[i] = GET_SWZ(element->swizzle, i);
> + assert(swiz[i] <= SWIZZLE_W);
> + }
> + def = nir_swizzle(b, def, swiz, intrin->num_components, true);
> +
> + /* and rewrite uses of original instruction: */
> + assert(intrin->dest.is_ssa);
> + nir_ssa_def_rewrite_uses(&intrin->dest.ssa, nir_src_for_ssa(def));
> +
> + /* at this point intrin should be unused. We need to remove it
> + * (rather than waiting for DCE pass) to avoid dangling reference
> + * to remove'd var. And we have to remove the original uniform
> + * var since we don't want it to get uniform space allocated.
> + */
> + exec_node_remove(&intrin->instr.node);
> + }
> +
> + return true;
> +}
> +
> +static void
> +lower_builtin_impl(lower_builtin_state *state, nir_function_impl *impl)
> +{
> + nir_builder_init(&state->builder, impl);
> + state->mem_ctx = ralloc_parent(impl);
> +
> + nir_foreach_block(impl, lower_builtin_block, state);
> +
> + nir_metadata_preserve(impl, nir_metadata_block_index |
> + nir_metadata_dominance);
> +}
> +
> +void
> +st_nir_lower_builtin(nir_shader *shader)
> +{
> + lower_builtin_state state;
> + state.shader = shader;
> + nir_foreach_function(shader, function) {
> + if (function->impl)
> + lower_builtin_impl(&state, function->impl);
> + }
> +}
> --
> 2.5.5
>
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