--- /dev/null
+/*
+ * Copyright © 2016 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"
+
+static void
+emit_load_store(nir_builder *b, nir_intrinsic_instr *orig_instr,
+ nir_deref_var *deref, nir_deref *tail,
+ nir_ssa_def **dest, nir_ssa_def *src);
+
+static void
+emit_indirect_load_store(nir_builder *b, nir_intrinsic_instr *orig_instr,
+ nir_deref_var *deref, nir_deref *arr_parent,
+ int start, int end,
+ nir_ssa_def **dest, nir_ssa_def *src)
+{
+ assert(arr_parent->child &&
+ arr_parent->child->deref_type == nir_deref_type_array);
+ nir_deref_array *arr = nir_deref_as_array(arr_parent->child);
+ assert(arr->deref_array_type == nir_deref_array_type_indirect);
+ assert(arr->indirect.is_ssa);
+
+ assert(start < end);
+ if (start == end - 1) {
+ /* Base case. Just emit the load/store op */
+ nir_deref_array direct = *arr;
+ direct.deref_array_type = nir_deref_array_type_direct;
+ direct.base_offset += start;
+ direct.indirect = NIR_SRC_INIT;
+
+ arr_parent->child = &direct.deref;
+ emit_load_store(b, orig_instr, deref, &arr->deref, dest, src);
+ arr_parent->child = &arr->deref;
+ } else {
+ int mid = start + (end - start) / 2;
+
+ nir_ssa_def *then_dest, *else_dest;
+
+ nir_if *if_stmt = nir_if_create(b->shader);
+ if_stmt->condition = nir_src_for_ssa(nir_ilt(b, arr->indirect.ssa,
+ nir_imm_int(b, mid)));
+ nir_cf_node_insert(b->cursor, &if_stmt->cf_node);
+
+ b->cursor = nir_after_cf_list(&if_stmt->then_list);
+ emit_indirect_load_store(b, orig_instr, deref, arr_parent,
+ start, mid, &then_dest, src);
+
+ b->cursor = nir_after_cf_list(&if_stmt->else_list);
+ emit_indirect_load_store(b, orig_instr, deref, arr_parent,
+ mid, end, &else_dest, src);
+
+ b->cursor = nir_after_cf_node(&if_stmt->cf_node);
+
+ if (src == NULL) {
+ /* We're a load. We need to insert a phi node */
+ nir_phi_instr *phi = nir_phi_instr_create(b->shader);
+ nir_ssa_dest_init(&phi->instr, &phi->dest,
+ then_dest->num_components, NULL);
+
+ nir_phi_src *src0 = ralloc(phi, nir_phi_src);
+ src0->pred = nir_cf_node_as_block(nir_if_last_then_node(if_stmt));
+ src0->src = nir_src_for_ssa(then_dest);
+ exec_list_push_tail(&phi->srcs, &src0->node);
+
+ nir_phi_src *src1 = ralloc(phi, nir_phi_src);
+ src1->pred = nir_cf_node_as_block(nir_if_last_else_node(if_stmt));
+ src1->src = nir_src_for_ssa(else_dest);
+ exec_list_push_tail(&phi->srcs, &src1->node);
+
+ nir_builder_instr_insert(b, &phi->instr);
+ *dest = &phi->dest.ssa;
+ }
+ }
+}
+
+static void
+emit_load_store(nir_builder *b, nir_intrinsic_instr *orig_instr,
+ nir_deref_var *deref, nir_deref *tail,
+ nir_ssa_def **dest, nir_ssa_def *src)
+{
+ for (; tail->child; tail = tail->child) {
+ if (tail->child->deref_type != nir_deref_type_array)
+ continue;
+
+ nir_deref_array *arr = nir_deref_as_array(tail->child);
+ if (arr->deref_array_type != nir_deref_array_type_indirect)
+ continue;
+
+ int length = glsl_get_length(tail->type);
+
+ emit_indirect_load_store(b, orig_instr, deref, tail, -arr->base_offset,
+ length - arr->base_offset, dest, src);
+ return;
+ }
+
+ assert(tail && tail->child == NULL);
+
+ /* We reached the end of the deref chain. Emit the instruction */
+
+ if (src == NULL) {
+ /* This is a load instruction */
+ nir_intrinsic_instr *load =
+ nir_intrinsic_instr_create(b->shader, nir_intrinsic_load_var);
+ load->num_components = orig_instr->num_components;
+ load->variables[0] =
+ nir_deref_as_var(nir_copy_deref(load, &deref->deref));
+ nir_ssa_dest_init(&load->instr, &load->dest,
+ load->num_components, NULL);
+ nir_builder_instr_insert(b, &load->instr);
+ *dest = &load->dest.ssa;
+ } else {
+ /* This is a store instruction */
+ nir_intrinsic_instr *store =
+ nir_intrinsic_instr_create(b->shader, nir_intrinsic_store_var);
+ store->num_components = orig_instr->num_components;
+ store->const_index[0] = orig_instr->const_index[0]; /* writemask */
+ store->variables[0] =
+ nir_deref_as_var(nir_copy_deref(store, &deref->deref));
+ store->src[0] = nir_src_for_ssa(src);
+ nir_builder_instr_insert(b, &store->instr);
+ }
+}
+
+static bool
+deref_has_indirect(nir_deref_var *deref)
+{
+ for (nir_deref *tail = deref->deref.child; tail; tail = tail->child) {
+ if (tail->deref_type != nir_deref_type_array)
+ continue;
+
+ nir_deref_array *arr = nir_deref_as_array(tail);
+ if (arr->deref_array_type == nir_deref_array_type_indirect)
+ return true;
+ }
+
+ return false;
+}
+
+struct lower_indirect_state {
+ nir_builder builder;
+ uint32_t mode_mask;
+ bool progress;
+};
+
+static bool
+lower_indirect_block(nir_block *block, void *void_state)
+{
+ struct lower_indirect_state *state = void_state;
+
+ 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 &&
+ intrin->intrinsic != nir_intrinsic_store_var)
+ continue;
+
+ if (!deref_has_indirect(intrin->variables[0]))
+ continue;
+
+ /* Only lower variables whose mode is in the mask */
+ if (!(state->mode_mask & (1 << intrin->variables[0]->var->data.mode)))
+ continue;
+
+ state->builder.cursor = nir_before_instr(&intrin->instr);
+
+ if (intrin->intrinsic == nir_intrinsic_load_var) {
+ nir_ssa_def *result;
+ emit_load_store(&state->builder, intrin, intrin->variables[0],
+ &intrin->variables[0]->deref, &result, NULL);
+ nir_ssa_def_rewrite_uses(&intrin->dest.ssa, nir_src_for_ssa(result));
+ } else {
+ assert(intrin->src[0].is_ssa);
+ emit_load_store(&state->builder, intrin, intrin->variables[0],
+ &intrin->variables[0]->deref, NULL, intrin->src[0].ssa);
+ }
+ nir_instr_remove(&intrin->instr);
+ state->progress = true;
+ }
+
+ return true;
+}
+
+static bool
+lower_indirects_impl(nir_function_impl *impl, uint32_t mode_mask)
+{
+ struct lower_indirect_state state;
+
+ state.progress = false;
+ state.mode_mask = mode_mask;
+ nir_builder_init(&state.builder, impl);
+
+ nir_foreach_block(impl, lower_indirect_block, &state);
+
+ if (state.progress)
+ nir_metadata_preserve(impl, nir_metadata_none);
+
+ return state.progress;
+}
+
+/** Lowers indirect variable loads/stores to direct loads/stores.
+ *
+ * The pass works by replacing any indirect load or store with an if-ladder
+ * that does a binary search on the array index.
+ */
+bool
+nir_lower_indirect_derefs(nir_shader *shader, uint32_t mode_mask)
+{
+ bool progress = false;
+
+ nir_foreach_function(shader, function) {
+ if (function->impl)
+ progress = lower_indirects_impl(function->impl, mode_mask) || progress;
+ }
+
+ return progress;
+}
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