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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.
*
* Authors:
* Jason Ekstrand (jason@jlekstrand.net)
*
*/
/*
* This lowering pass detects when a global variable is only being used by
* one function and makes it local to that function
*/
#include "nir.h"
static void
register_var_use(nir_variable *var, nir_function_impl *impl,
struct hash_table *var_func_table)
{
if (var->data.mode != nir_var_private)
return;
struct hash_entry *entry =
_mesa_hash_table_search(var_func_table, var);
if (entry) {
if (entry->data != impl)
entry->data = NULL;
} else {
_mesa_hash_table_insert(var_func_table, var, impl);
}
}
static bool
mark_global_var_uses_block(nir_block *block, nir_function_impl *impl,
struct hash_table *var_func_table)
{
nir_foreach_instr(instr, block) {
if (instr->type == nir_instr_type_deref) {
nir_deref_instr *deref = nir_instr_as_deref(instr);
if (deref->deref_type == nir_deref_type_var)
register_var_use(deref->var, impl, var_func_table);
}
}
return true;
}
bool
nir_lower_global_vars_to_local(nir_shader *shader)
{
bool progress = false;
/* A hash table keyed on variable pointers that stores the unique
* nir_function_impl that uses the given variable. If a variable is
* used in multiple functions, the data for the given key will be NULL.
*/
struct hash_table *var_func_table = _mesa_pointer_hash_table_create(NULL);
nir_foreach_function(function, shader) {
if (function->impl) {
nir_foreach_block(block, function->impl)
mark_global_var_uses_block(block, function->impl, var_func_table);
}
}
hash_table_foreach(var_func_table, entry) {
nir_variable *var = (void *)entry->key;
nir_function_impl *impl = entry->data;
assert(var->data.mode == nir_var_private);
if (impl != NULL) {
exec_node_remove(&var->node);
var->data.mode = nir_var_function;
exec_list_push_tail(&impl->locals, &var->node);
nir_metadata_preserve(impl, nir_metadata_block_index |
nir_metadata_dominance |
nir_metadata_live_ssa_defs);
progress = true;
}
}
_mesa_hash_table_destroy(var_func_table, NULL);
if (progress)
nir_fixup_deref_modes(shader);
#ifndef NDEBUG
nir_foreach_function(function, shader) {
if (function->impl) {
function->impl->valid_metadata &= ~nir_metadata_not_properly_reset;
}
}
#endif
return progress;
}
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