/*
* Copyright © 2010 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 opt_structure_splitting.cpp
*
* If a structure is only ever referenced by its components, then
* split those components out to individual variables so they can be
* handled normally by other optimization passes.
*
* This skips structures like uniforms, which need to be accessible as
* structures for their access by the GL.
*/
#include "ir.h"
#include "ir_visitor.h"
#include "ir_rvalue_visitor.h"
#include "glsl_types.h"
namespace {
static bool debug = false;
class variable_entry : public exec_node
{
public:
variable_entry(ir_variable *var)
{
this->var = var;
this->whole_structure_access = 0;
this->declaration = false;
this->components = NULL;
this->mem_ctx = NULL;
}
ir_variable *var; /* The key: the variable's pointer. */
/** Number of times the variable is referenced, including assignments. */
unsigned whole_structure_access;
/* If the variable had a decl we can work with in the instruction
* stream. We can't do splitting on function arguments, which
* don't get this variable set.
*/
bool declaration;
ir_variable **components;
/** ralloc_parent(this->var) -- the shader's ralloc context. */
void *mem_ctx;
};
class ir_structure_reference_visitor : public ir_hierarchical_visitor {
public:
ir_structure_reference_visitor(void)
{
this->mem_ctx = ralloc_context(NULL);
this->variable_list.make_empty();
}
~ir_structure_reference_visitor(void)
{
ralloc_free(mem_ctx);
}
virtual ir_visitor_status visit(ir_variable *);
virtual ir_visitor_status visit(ir_dereference_variable *);
virtual ir_visitor_status visit_enter(ir_dereference_record *);
virtual ir_visitor_status visit_enter(ir_assignment *);
virtual ir_visitor_status visit_enter(ir_function_signature *);
variable_entry *get_variable_entry(ir_variable *var);
/* List of variable_entry */
exec_list variable_list;
void *mem_ctx;
};
variable_entry *
ir_structure_reference_visitor::get_variable_entry(ir_variable *var)
{
assert(var);
if (!var->type->is_record() || var->mode == ir_var_uniform
|| var->mode == ir_var_shader_in || var->mode == ir_var_shader_out)
return NULL;
foreach_iter(exec_list_iterator, iter, this->variable_list) {
variable_entry *entry = (variable_entry *)iter.get();
if (entry->var == var)
return entry;
}
variable_entry *entry = new(mem_ctx) variable_entry(var);
this->variable_list.push_tail(entry);
return entry;
}
ir_visitor_status
ir_structure_reference_visitor::visit(ir_variable *ir)
{
variable_entry *entry = this->get_variable_entry(ir);
if (entry)
entry->declaration = true;
return visit_continue;
}
ir_visitor_status
ir_structure_reference_visitor::visit(ir_dereference_variable *ir)
{
ir_variable *const var = ir->variable_referenced();
variable_entry *entry = this->get_variable_entry(var);
if (entry)
entry->whole_structure_access++;
return visit_continue;
}
ir_visitor_status
ir_structure_reference_visitor::visit_enter(ir_dereference_record *ir)
{
(void) ir;
/* Don't descend into the ir_dereference_variable below. */
return visit_continue_with_parent;
}
ir_visitor_status
ir_structure_reference_visitor::visit_enter(ir_assignment *ir)
{
/* If there are no structure references yet, no need to bother with
* processing the expression tree.
*/
if (this->variable_list.is_empty())
return visit_continue_with_parent;
if (ir->lhs->as_dereference_variable() &&
ir->rhs->as_dereference_variable() &&
!ir->condition) {
/* We'll split copies of a structure to copies of components, so don't
* descend to the ir_dereference_variables.
*/
return visit_continue_with_parent;
}
return visit_continue;
}
ir_visitor_status
ir_structure_reference_visitor::visit_enter(ir_function_signature *ir)
{
/* We don't have logic for structure-splitting function arguments,
* so just look at the body instructions and not the parameter
* declarations.
*/
visit_list_elements(this, &ir->body);
return visit_continue_with_parent;
}
class ir_structure_splitting_visitor : public ir_rvalue_visitor {
public:
ir_structure_splitting_visitor(exec_list *vars)
{
this->variable_list = vars;
}
virtual ~ir_structure_splitting_visitor()
{
}
virtual ir_visitor_status visit_leave(ir_assignment *);
void split_deref(ir_dereference **deref);
void handle_rvalue(ir_rvalue **rvalue);
variable_entry *get_splitting_entry(ir_variable *var);
exec_list *variable_list;
};
variable_entry *
ir_structure_splitting_visitor::get_splitting_entry(ir_variable *var)
{
assert(var);
if (!var->type->is_record())
return NULL;
foreach_iter(exec_list_iterator, iter, *this->variable_list) {
variable_entry *entry = (variable_entry *)iter.get();
if (entry->var == var) {
return entry;
}
}
return NULL;
}
void
ir_structure_splitting_visitor::split_deref(ir_dereference **deref)
{
if ((*deref)->ir_type != ir_type_dereference_record)
return;
ir_dereference_record *deref_record = (ir_dereference_record *)*deref;
ir_dereference_variable *deref_var = deref_record->record->as_dereference_variable();
if (!deref_var)
return;
variable_entry *entry = get_splitting_entry(deref_var->var);
if (!entry)
return;
unsigned int i;
for (i = 0; i < entry->var->type->length; i++) {
if (strcmp(deref_record->field,
entry->var->type->fields.structure[i].name) == 0)
break;
}
assert(i != entry->var->type->length);
*deref = new(entry->mem_ctx) ir_dereference_variable(entry->components[i]);
}
void
ir_structure_splitting_visitor::handle_rvalue(ir_rvalue **rvalue)
{
if (!*rvalue)
return;
ir_dereference *deref = (*rvalue)->as_dereference();
if (!deref)
return;
split_deref(&deref);
*rvalue = deref;
}
ir_visitor_status
ir_structure_splitting_visitor::visit_leave(ir_assignment *ir)
{
ir_dereference_variable *lhs_deref = ir->lhs->as_dereference_variable();
ir_dereference_variable *rhs_deref = ir->rhs->as_dereference_variable();
variable_entry *lhs_entry = lhs_deref ? get_splitting_entry(lhs_deref->var) : NULL;
variable_entry *rhs_entry = rhs_deref ? get_splitting_entry(rhs_deref->var) : NULL;
const glsl_type *type = ir->rhs->type;
if ((lhs_entry || rhs_entry) && !ir->condition) {
for (unsigned int i = 0; i < type->length; i++) {
ir_dereference *new_lhs, *new_rhs;
void *mem_ctx = lhs_entry ? lhs_entry->mem_ctx : rhs_entry->mem_ctx;
if (lhs_entry) {
new_lhs = new(mem_ctx) ir_dereference_variable(lhs_entry->components[i]);
} else {
new_lhs = new(mem_ctx)
ir_dereference_record(ir->lhs->clone(mem_ctx, NULL),
type->fields.structure[i].name);
}
if (rhs_entry) {
new_rhs = new(mem_ctx) ir_dereference_variable(rhs_entry->components[i]);
} else {
new_rhs = new(mem_ctx)
ir_dereference_record(ir->rhs->clone(mem_ctx, NULL),
type->fields.structure[i].name);
}
ir->insert_before(new(mem_ctx) ir_assignment(new_lhs,
new_rhs,
NULL));
}
ir->remove();
} else {
handle_rvalue(&ir->rhs);
split_deref(&ir->lhs);
}
handle_rvalue(&ir->condition);
return visit_continue;
}
} /* unnamed namespace */
bool
do_structure_splitting(exec_list *instructions)
{
ir_structure_reference_visitor refs;
visit_list_elements(&refs, instructions);
/* Trim out variables we can't split. */
foreach_iter(exec_list_iterator, iter, refs.variable_list) {
variable_entry *entry = (variable_entry *)iter.get();
if (debug) {
printf("structure %s@%p: decl %d, whole_access %d\n",
entry->var->name, (void *) entry->var, entry->declaration,
entry->whole_structure_access);
}
if (!entry->declaration || entry->whole_structure_access) {
entry->remove();
}
}
if (refs.variable_list.is_empty())
return false;
void *mem_ctx = ralloc_context(NULL);
/* Replace the decls of the structures to be split with their split
* components.
*/
foreach_iter(exec_list_iterator, iter, refs.variable_list) {
variable_entry *entry = (variable_entry *)iter.get();
const struct glsl_type *type = entry->var->type;
entry->mem_ctx = ralloc_parent(entry->var);
entry->components = ralloc_array(mem_ctx,
ir_variable *,
type->length);
for (unsigned int i = 0; i < entry->var->type->length; i++) {
const char *name = ralloc_asprintf(mem_ctx, "%s_%s",
entry->var->name,
type->fields.structure[i].name);
entry->components[i] =
new(entry->mem_ctx) ir_variable(type->fields.structure[i].type,
name,
ir_var_temporary);
entry->var->insert_before(entry->components[i]);
}
entry->var->remove();
}
ir_structure_splitting_visitor split(&refs.variable_list);
visit_list_elements(&split, instructions);
ralloc_free(mem_ctx);
return true;
}