/* * Copyright © 2020 Mike Blumenkrantz * * 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. * * Authors: * Mike Blumenkrantz */ #include "nir.h" #include "nir_builder.h" bool nir_lower_dynamic_bo_access(nir_shader *shader); /** * This pass converts dynamic UBO/SSBO block indices to constant indices by generating * conditional chains which reduce to single values. * * This is needed by anything which intends to convert GLSL-like shaders to SPIRV, * as SPIRV requires explicit load points for UBO/SSBO variables and has no instruction for * loading based on an offset in the underlying driver's binding table */ /* generate a single ssa value which conditionally selects the right value that * was previously loaded by the load_ubo conditional chain */ static nir_ssa_def * recursive_generate_bo_ssa_def(nir_builder *b, nir_intrinsic_instr *instr, nir_ssa_def *index, unsigned start, unsigned end) { if (start == end - 1) { nir_intrinsic_instr *new_instr = nir_intrinsic_instr_create(b->shader, instr->intrinsic); new_instr->src[0] = nir_src_for_ssa(nir_imm_int(b, start)); for (unsigned i = 0; i < nir_intrinsic_infos[instr->intrinsic].num_srcs; i++) { if (i) nir_src_copy(&new_instr->src[i], &instr->src[i]); } if (instr->intrinsic != nir_intrinsic_load_ubo_vec4) { nir_intrinsic_set_align(new_instr, nir_intrinsic_align_mul(instr), nir_intrinsic_align_offset(instr)); if (instr->intrinsic != nir_intrinsic_load_ssbo) nir_intrinsic_set_range(new_instr, nir_intrinsic_range(instr)); } new_instr->num_components = instr->num_components; nir_ssa_dest_init(&new_instr->instr, &new_instr->dest, nir_dest_num_components(instr->dest), nir_dest_bit_size(instr->dest), NULL); nir_builder_instr_insert(b, &new_instr->instr); return &new_instr->dest.ssa; } unsigned mid = start + (end - start) / 2; return nir_build_alu(b, nir_op_bcsel, nir_build_alu(b, nir_op_ilt, index, nir_imm_int(b, mid), NULL, NULL), recursive_generate_bo_ssa_def(b, instr, index, start, mid), recursive_generate_bo_ssa_def(b, instr, index, mid, end), NULL ); } static void generate_store_ssbo_ssa_def(nir_builder *b, nir_intrinsic_instr *instr, nir_ssa_def *index, unsigned start, unsigned end) { if (start == end - 1) { nir_intrinsic_instr *new_instr = nir_instr_as_intrinsic(nir_instr_clone(b->shader, &instr->instr)); new_instr->src[1] = nir_src_for_ssa(nir_imm_int(b, start)); nir_builder_instr_insert(b, &new_instr->instr); } else { int mid = start + (end - start) / 2; nir_ssa_def *mid_idx = nir_imm_int(b, mid); nir_push_if(b, nir_ilt(b, index, mid_idx)); generate_store_ssbo_ssa_def(b, instr, index, start, mid); nir_push_else(b, NULL); generate_store_ssbo_ssa_def(b, instr, index, mid, end); nir_pop_if(b, NULL); } } static bool lower_dynamic_bo_access_instr(nir_builder *b, nir_instr *instr_, UNUSED void *cb_data) { if (instr_->type != nir_instr_type_intrinsic) return false; nir_intrinsic_instr *instr = nir_instr_as_intrinsic(instr_); if (instr->intrinsic != nir_intrinsic_load_ubo && instr->intrinsic != nir_intrinsic_load_ubo_vec4 && instr->intrinsic != nir_intrinsic_get_ssbo_size && instr->intrinsic != nir_intrinsic_load_ssbo && instr->intrinsic != nir_intrinsic_store_ssbo) return false; /* block index src is 1 for this op */ unsigned block_idx = instr->intrinsic == nir_intrinsic_store_ssbo; if (nir_src_is_const(instr->src[block_idx])) return false; b->cursor = nir_after_instr(&instr->instr); bool ssbo_mode = instr->intrinsic != nir_intrinsic_load_ubo && instr->intrinsic != nir_intrinsic_load_ubo_vec4; unsigned first_idx = UINT_MAX, last_idx; if (ssbo_mode) { nir_foreach_variable_with_modes(var, b->shader, nir_var_mem_ssbo) first_idx = MIN2(first_idx, var->data.driver_location); last_idx = first_idx + b->shader->info.num_ssbos; } else { /* skip 0 index if uniform_0 is one we created previously */ first_idx = !b->shader->info.first_ubo_is_default_ubo; last_idx = first_idx + b->shader->info.num_ubos; } if (instr->intrinsic != nir_intrinsic_store_ssbo) { /* now create the composite dest with a bcsel chain based on the original value */ nir_ssa_def *new_dest = recursive_generate_bo_ssa_def(b, instr, instr->src[block_idx].ssa, first_idx, last_idx); /* now use the composite dest in all cases where the original dest (from the dynamic index) * was used and remove the dynamically-indexed load_*bo instruction */ nir_ssa_def_rewrite_uses_after(&instr->dest.ssa, new_dest, &instr->instr); } else generate_store_ssbo_ssa_def(b, instr, instr->src[block_idx].ssa, first_idx, last_idx); nir_instr_remove(&instr->instr); return true; } bool nir_lower_dynamic_bo_access(nir_shader *shader) { return nir_shader_instructions_pass(shader, lower_dynamic_bo_access_instr, nir_metadata_dominance, NULL); }