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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"
struct global_to_local_state {
nir_function_impl *impl;
/* 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;
};
static bool
mark_global_var_uses_block(nir_block *block, void *void_state)
{
struct global_to_local_state *state = void_state;
nir_foreach_instr(block, instr) {
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
unsigned num_vars = nir_intrinsic_infos[intrin->intrinsic].num_variables;
for (unsigned i = 0; i < num_vars; i++) {
nir_variable *var = intrin->variables[i]->var;
if (var->data.mode != nir_var_global)
continue;
struct hash_entry *entry =
_mesa_hash_table_search(state->var_func_table, var);
if (entry) {
if (entry->data != state->impl)
entry->data = NULL;
} else {
_mesa_hash_table_insert(state->var_func_table, var, state->impl);
}
}
}
return true;
}
bool
nir_lower_global_vars_to_local(nir_shader *shader)
{
struct global_to_local_state state;
bool progress = false;
state.var_func_table = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
_mesa_key_pointer_equal);
nir_foreach_function(shader, function) {
if (function->impl) {
state.impl = function->impl;
nir_foreach_block(function->impl, mark_global_var_uses_block, &state);
}
}
struct hash_entry *entry;
hash_table_foreach(state.var_func_table, entry) {
nir_variable *var = (void *)entry->key;
nir_function_impl *impl = entry->data;
assert(var->data.mode == nir_var_global);
if (impl != NULL) {
exec_node_remove(&var->node);
var->data.mode = nir_var_local;
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(state.var_func_table, NULL);
return progress;
}
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