From 26aa460940f6222565ad5eb40a21c2377c59c3a6 Mon Sep 17 00:00:00 2001 From: Timothy Arceri Date: Mon, 10 Dec 2018 10:23:51 +1100 Subject: [PATCH] nir: rewrite varying component packing There are a number of reasons for the rewrite. 1. Adding support for packing tess patch varyings in a sane way. 2. Making use of qsort allowing the code to be much easier to follow. 3. Fixes a bug where different interp types caused component packing to be skipped for all varyings in some scenarios. 4. Allows us to add a crude live range analysis for deciding which components should be packed together. This support can optionally be added in a future patch. Reviewed-by: Jason Ekstrand --- src/compiler/nir/nir_linking_helpers.c | 356 ++++++++++++++++++------- 1 file changed, 254 insertions(+), 102 deletions(-) diff --git a/src/compiler/nir/nir_linking_helpers.c b/src/compiler/nir/nir_linking_helpers.c index d74cc6c8788..b387d104d58 100644 --- a/src/compiler/nir/nir_linking_helpers.c +++ b/src/compiler/nir/nir_linking_helpers.c @@ -238,22 +238,29 @@ is_packing_supported_for_type(const struct glsl_type *type) 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; +}; + +/* 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_slot_component_masks_and_interp_types(struct exec_list *var_list, - uint8_t *comps, - uint8_t *interp_type, - uint8_t *interp_loc, - gl_shader_stage stage, - bool default_to_smooth_interp) +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. - * TODO: add TES patch support. - */ + /* Only remap things that aren't built-ins. */ if (var->data.location >= VARYING_SLOT_VAR0 && - var->data.location - VARYING_SLOT_VAR0 < 32) { + 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)) { @@ -261,37 +268,44 @@ get_slot_component_masks_and_interp_types(struct exec_list *var_list, 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_get_vector_elements(glsl_without_array(type)); 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++) { - interp_type[location + i] = - get_interp_type(var, type, default_to_smooth_interp); - interp_loc[location + i] = get_interp_loc(var); - if (dual_slot) { if (i & 1) { - comps[location + i] |= ((1 << comps_slot2) - 1); + comps[location + i].comps |= ((1 << comps_slot2) - 1); } else { unsigned num_comps = 4 - var->data.location_frac; - comps_slot2 = (elements * 2) - num_comps; + 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[location + i].comps |= ((1 << num_comps) - 1) << var->data.location_frac; } } else { - comps[location + i] |= - ((1 << elements) - 1) << var->data.location_frac; + 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); } } } @@ -403,32 +417,55 @@ remap_slots_and_components(struct exec_list *var_list, gl_shader_stage stage, *p_out_slots_read = out_slots_read_tmp[1]; } -/* 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, uint8_t *comps, - uint8_t *interp_type, uint8_t *interp_loc, - bool default_to_smooth_interp) +struct varying_component { + nir_variable *var; + uint8_t interp_type; + uint8_t interp_loc; + bool is_patch; + bool initialised; +}; + +static int +cmp_varying_component(const void *comp1_v, const void *comp2_v) { - 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 *comp1 = (struct varying_component *) comp1_v; + struct varying_component *comp2 = (struct varying_component *) comp2_v; - /* Create a cursor for each interpolation type */ - unsigned cursor[4] = {0}; + /* 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 only need to pass over one stage and we choose the consumer as it seems - * to cause a larger reduction in instruction counts (tested on i965). + /* We can only pack varyings with matching interpolation types so group + * them together. */ - nir_foreach_variable(var, input_list) { + 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; - /* Only remap things that aren't builtins. - * TODO: add TES patch support. - */ + /* 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 < 32) { + var->data.location - VARYING_SLOT_VAR0 < MAX_VARYINGS_INCL_PATCH) { /* We can't repack xfb varyings. */ if (var->data.always_active_io) @@ -443,72 +480,191 @@ compact_components(nir_shader *producer, nir_shader *consumer, uint8_t *comps, if (!is_packing_supported_for_type(type)) continue; - unsigned location = var->data.location - VARYING_SLOT_VAR0; - uint8_t used_comps = comps[location]; + unsigned loc = var->data.location - VARYING_SLOT_VAR0; + store_varying_info_idx[loc][var->data.location_frac] = + ++num_of_comps_to_pack; + } + } - /* If there are no empty components there is nothing more for us to do. - */ - if (used_comps == 0xf) - continue; + *varying_comp_info_size = num_of_comps_to_pack; + *varying_comp_info = rzalloc_array(NULL, struct varying_component, + num_of_comps_to_pack); - bool found_new_offset = false; - uint8_t interp = get_interp_type(var, type, default_to_smooth_interp); - for (; cursor[interp] < 32; cursor[interp]++) { - uint8_t cursor_used_comps = comps[cursor[interp]]; + nir_function_impl *impl = nir_shader_get_entrypoint(consumer); - /* We couldn't find anywhere to pack the varying continue on. */ - if (cursor[interp] == location && - (var->data.location_frac == 0 || - cursor_used_comps & ((1 << (var->data.location_frac)) - 1))) - break; + /* 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; - /* We can only pack varyings with matching interpolation types */ - if (interp_type[cursor[interp]] != interp) - 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; - /* Interpolation loc must match also. - * TODO: i965 can handle these if they 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 (interp_loc[cursor[interp]] != get_interp_loc(var)) - continue; + nir_deref_instr *deref = nir_src_as_deref(intr->src[0]); + if (deref->mode != nir_var_shader_in) + continue; - /* If the slot is empty just skip it for now, compact_var_list() - * can be called after this function to remove empty slots for us. - * TODO: finish implementing compact_var_list() requires array and - * matrix splitting. - */ - if (!cursor_used_comps) - 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; - uint8_t unused_comps = ~cursor_used_comps; + unsigned location = in_var->data.location - VARYING_SLOT_VAR0; + if (location >= MAX_VARYINGS_INCL_PATCH) + continue; - for (unsigned i = 0; i < 4; i++) { - uint8_t new_var_comps = 1 << i; - if (unused_comps & new_var_comps) { - remap[location][var->data.location_frac].component = i; - remap[location][var->data.location_frac].location = - cursor[interp] + VARYING_SLOT_VAR0; + unsigned var_info_idx = + store_varying_info_idx[location][in_var->data.location_frac]; + if (!var_info_idx) + continue; - found_new_offset = true; + struct varying_component *vc_info = + &(*varying_comp_info)[var_info_idx-1]; - /* Turn off the mask for the component we are remapping */ - if (comps[location] & 1 << var->data.location_frac) { - comps[location] ^= 1 << var->data.location_frac; - comps[cursor[interp]] |= new_var_comps; - } - break; - } + 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); } - if (found_new_offset) - break; + 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_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; + } + + 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; + + /* 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; @@ -539,20 +695,16 @@ nir_compact_varyings(nir_shader *producer, nir_shader *consumer, assert(producer->info.stage != MESA_SHADER_FRAGMENT); assert(consumer->info.stage != MESA_SHADER_VERTEX); - uint8_t comps[32] = {0}; - uint8_t interp_type[32] = {0}; - uint8_t interp_loc[32] = {0}; + struct assigned_comps assigned_comps[MAX_VARYINGS_INCL_PATCH] = {0}; - get_slot_component_masks_and_interp_types(&producer->outputs, comps, - interp_type, interp_loc, - producer->info.stage, - default_to_smooth_interp); - get_slot_component_masks_and_interp_types(&consumer->inputs, comps, - interp_type, interp_loc, - consumer->info.stage, - default_to_smooth_interp); + 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, comps, interp_type, interp_loc, + compact_components(producer, consumer, assigned_comps, default_to_smooth_interp); } -- 2.30.2