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/*
* Copyright © 2014 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.
*/
/**
* \file lower_const_arrays_to_uniforms.cpp
*
* Lower constant arrays to uniform arrays.
*
* Some driver backends (such as i965 and nouveau) don't handle constant arrays
* gracefully, instead treating them as ordinary writable temporary arrays.
* Since arrays can be large, this often means spilling them to scratch memory,
* which usually involves a large number of instructions.
*
* This must be called prior to link_set_uniform_initializers(); we need the
* linker to process our new uniform's constant initializer.
*
* This should be called after optimizations, since those can result in
* splitting and removing arrays that are indexed by constant expressions.
*/
#include "ir.h"
#include "ir_visitor.h"
#include "ir_rvalue_visitor.h"
#include "compiler/glsl_types.h"
namespace {
class lower_const_array_visitor : public ir_rvalue_visitor {
public:
lower_const_array_visitor(exec_list *insts, unsigned s,
unsigned available_uni_components)
{
instructions = insts;
stage = s;
const_count = 0;
free_uni_components = available_uni_components;
progress = false;
}
bool run()
{
visit_list_elements(this, instructions);
return progress;
}
ir_visitor_status visit_enter(ir_texture *);
void handle_rvalue(ir_rvalue **rvalue);
private:
exec_list *instructions;
unsigned stage;
unsigned const_count;
unsigned free_uni_components;
bool progress;
};
ir_visitor_status
lower_const_array_visitor::visit_enter(ir_texture *)
{
return visit_continue_with_parent;
}
void
lower_const_array_visitor::handle_rvalue(ir_rvalue **rvalue)
{
if (!*rvalue)
return;
ir_constant *con = (*rvalue)->as_constant();
if (!con || !con->type->is_array())
return;
/* How many uniform component slots are required? */
unsigned component_slots = con->type->component_slots();
/* We would utilize more than is available, bail out. */
if (component_slots > free_uni_components)
return;
free_uni_components -= component_slots;
void *mem_ctx = ralloc_parent(con);
/* In the very unlikely event of 4294967295 constant arrays in a single
* shader, don't promote this to a uniform.
*/
unsigned limit = ~0;
if (const_count == limit)
return;
char *uniform_name = ralloc_asprintf(mem_ctx, "constarray_%x_%u",
const_count, stage);
const_count++;
ir_variable *uni =
new(mem_ctx) ir_variable(con->type, uniform_name, ir_var_uniform);
uni->constant_initializer = con;
uni->constant_value = con;
uni->data.has_initializer = true;
uni->data.how_declared = ir_var_hidden;
uni->data.read_only = true;
/* Assume the whole thing is accessed. */
uni->data.max_array_access = uni->type->length - 1;
instructions->push_head(uni);
*rvalue = new(mem_ctx) ir_dereference_variable(uni);
progress = true;
}
} /* anonymous namespace */
static unsigned
count_uniforms(exec_list *instructions)
{
unsigned total = 0;
foreach_in_list(ir_instruction, node, instructions) {
ir_variable *const var = node->as_variable();
if (!var || var->data.mode != ir_var_uniform)
continue;
total += var->type->component_slots();
}
return total;
}
bool
lower_const_arrays_to_uniforms(exec_list *instructions, unsigned stage,
unsigned max_uniform_components)
{
unsigned uniform_components = count_uniforms(instructions);
unsigned free_uniform_slots = max_uniform_components - uniform_components;
lower_const_array_visitor v(instructions, stage, free_uniform_slots);
return v.run();
}