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* Copyright © 2014 Intel Corporation
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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* \file lower_const_arrays_to_uniforms.cpp
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* Lower constant arrays to uniform arrays.
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* Some driver backends (such as i965 and nouveau) don't handle constant arrays
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* gracefully, instead treating them as ordinary writable temporary arrays.
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* Since arrays can be large, this often means spilling them to scratch memory,
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* which usually involves a large number of instructions.
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* This must be called prior to link_set_uniform_initializers(); we need the
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* linker to process our new uniform's constant initializer.
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* This should be called after optimizations, since those can result in
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* splitting and removing arrays that are indexed by constant expressions.
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#include "ir_visitor.h"
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#include "ir_rvalue_visitor.h"
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#include "compiler/glsl_types.h"
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class lower_const_array_visitor : public ir_rvalue_visitor {
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lower_const_array_visitor(exec_list *insts, unsigned s,
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unsigned available_uni_components)
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free_uni_components = available_uni_components;
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visit_list_elements(this, instructions);
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ir_visitor_status visit_enter(ir_texture *);
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void handle_rvalue(ir_rvalue **rvalue);
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exec_list *instructions;
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unsigned free_uni_components;
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lower_const_array_visitor::visit_enter(ir_texture *)
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return visit_continue_with_parent;
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lower_const_array_visitor::handle_rvalue(ir_rvalue **rvalue)
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ir_constant *con = (*rvalue)->as_constant();
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if (!con || !con->type->is_array())
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/* How many uniform component slots are required? */
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unsigned component_slots = con->type->component_slots();
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/* We would utilize more than is available, bail out. */
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if (component_slots > free_uni_components)
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free_uni_components -= component_slots;
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void *mem_ctx = ralloc_parent(con);
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/* In the very unlikely event of 4294967295 constant arrays in a single
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* shader, don't promote this to a uniform.
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if (const_count == limit)
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char *uniform_name = ralloc_asprintf(mem_ctx, "constarray_%x_%u",
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new(mem_ctx) ir_variable(con->type, uniform_name, ir_var_uniform);
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uni->constant_initializer = con;
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uni->constant_value = con;
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uni->data.has_initializer = true;
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uni->data.how_declared = ir_var_hidden;
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uni->data.read_only = true;
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/* Assume the whole thing is accessed. */
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uni->data.max_array_access = uni->type->length - 1;
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instructions->push_head(uni);
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*rvalue = new(mem_ctx) ir_dereference_variable(uni);
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} /* anonymous namespace */
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count_uniforms(exec_list *instructions)
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foreach_in_list(ir_instruction, node, instructions) {
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ir_variable *const var = node->as_variable();
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if (!var || var->data.mode != ir_var_uniform)
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total += var->type->component_slots();
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lower_const_arrays_to_uniforms(exec_list *instructions, unsigned stage,
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unsigned max_uniform_components)
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unsigned uniform_components = count_uniforms(instructions);
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unsigned free_uniform_slots = max_uniform_components - uniform_components;
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lower_const_array_visitor v(instructions, stage, free_uniform_slots);