/*
* 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 brw_wm_vector_splitting.cpp
*
* If a vector 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 vectors in uniforms and varyings, which need to be
* accessible as vectors for their access by the GL. Also, vector
* results of non-variable-derefs in assignments aren't handled
* because to do so we would have to store the vector result to a
* temporary in order to unload each channel, and to do so would just
* loop us back to where we started. For the 965, this is exactly the
* behavior we want for the results of texture lookups, but probably not for
*/
#include "main/core.h"
#include "brw_context.h"
#include "glsl/ir.h"
#include "glsl/ir_visitor.h"
#include "glsl/ir_rvalue_visitor.h"
#include "glsl/glsl_types.h"
static bool debug = false;
class variable_entry : public exec_node
{
public:
variable_entry(ir_variable *var)
{
this->var = var;
this->whole_vector_access = 0;
this->mem_ctx = NULL;
}
ir_variable *var; /* The key: the variable's pointer. */
/** Number of times the variable is referenced, including assignments. */
unsigned whole_vector_access;
ir_variable *components[4];
/** ralloc_parent(this->var) -- the shader's ralloc context. */
void *mem_ctx;
};
class ir_vector_reference_visitor : public ir_hierarchical_visitor {
public:
ir_vector_reference_visitor(void)
{
this->mem_ctx = ralloc_context(NULL);
this->variable_list.make_empty();
}
~ir_vector_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_swizzle *);
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_vector_reference_visitor::get_variable_entry(ir_variable *var)
{
assert(var);
if (!var->type->is_vector())
return NULL;
switch (var->data.mode) {
case ir_var_uniform:
case ir_var_shader_in:
case ir_var_shader_out:
case ir_var_system_value:
case ir_var_function_in:
case ir_var_function_out:
case ir_var_function_inout:
/* Can't split varyings or uniforms. Function in/outs won't get split
* either.
*/
return NULL;
case ir_var_auto:
case ir_var_temporary:
break;
}
foreach_in_list(variable_entry, entry, &variable_list) {
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_vector_reference_visitor::visit(ir_variable *ir)
{
/* Make sure splitting looks at splitting this variable */
(void)this->get_variable_entry(ir);
return visit_continue;
}
ir_visitor_status
ir_vector_reference_visitor::visit(ir_dereference_variable *ir)
{
ir_variable *const var = ir->var;
variable_entry *entry = this->get_variable_entry(var);
if (entry)
entry->whole_vector_access++;
return visit_continue;
}
ir_visitor_status
ir_vector_reference_visitor::visit_enter(ir_swizzle *ir)
{
/* Don't descend into a vector ir_dereference_variable below. */
if (ir->val->as_dereference_variable() && ir->type->is_scalar())
return visit_continue_with_parent;
return visit_continue;
}
ir_visitor_status
ir_vector_reference_visitor::visit_enter(ir_assignment *ir)
{
if (ir->lhs->as_dereference_variable() &&
ir->rhs->as_dereference_variable() &&
!ir->condition) {
/* We'll split copies of a vector to copies of channels, so don't
* descend to the ir_dereference_variables.
*/
return visit_continue_with_parent;
}
if (ir->lhs->as_dereference_variable() &&
is_power_of_two(ir->write_mask) &&
!ir->condition) {
/* If we're writing just a channel, then channel-splitting the LHS is OK.
*/
ir->rhs->accept(this);
return visit_continue_with_parent;
}
return visit_continue;
}
ir_visitor_status
ir_vector_reference_visitor::visit_enter(ir_function_signature *ir)
{
/* We don't want to descend into the function parameters and
* split them, so just accept the body here.
*/
visit_list_elements(this, &ir->body);
return visit_continue_with_parent;
}
class ir_vector_splitting_visitor : public ir_rvalue_visitor {
public:
ir_vector_splitting_visitor(exec_list *vars)
{
this->variable_list = vars;
}
virtual ir_visitor_status visit_leave(ir_assignment *);
void handle_rvalue(ir_rvalue **rvalue);
variable_entry *get_splitting_entry(ir_variable *var);
exec_list *variable_list;
};
variable_entry *
ir_vector_splitting_visitor::get_splitting_entry(ir_variable *var)
{
assert(var);
if (!var->type->is_vector())
return NULL;
foreach_in_list(variable_entry, entry, variable_list) {
if (entry->var == var) {
return entry;
}
}
return NULL;
}
void
ir_vector_splitting_visitor::handle_rvalue(ir_rvalue **rvalue)
{
if (!*rvalue)
return;
ir_swizzle *swiz = (*rvalue)->as_swizzle();
if (!swiz || !swiz->type->is_scalar())
return;
ir_dereference_variable *deref_var = swiz->val->as_dereference_variable();
if (!deref_var)
return;
variable_entry *entry = get_splitting_entry(deref_var->var);
if (!entry)
return;
ir_variable *var = entry->components[swiz->mask.x];
*rvalue = new(entry->mem_ctx) ir_dereference_variable(var);
}
ir_visitor_status
ir_vector_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 = lhs_deref ? get_splitting_entry(lhs_deref->var) : NULL;
variable_entry *rhs = rhs_deref ? get_splitting_entry(rhs_deref->var) : NULL;
if (lhs_deref && rhs_deref && (lhs || rhs) && !ir->condition) {
unsigned int rhs_chan = 0;
/* Straight assignment of vector variables. */
for (unsigned int i = 0; i < ir->lhs->type->vector_elements; i++) {
ir_dereference *new_lhs;
ir_rvalue *new_rhs;
void *mem_ctx = lhs ? lhs->mem_ctx : rhs->mem_ctx;
unsigned int writemask;
if (!(ir->write_mask & (1 << i)))
continue;
if (lhs) {
new_lhs = new(mem_ctx) ir_dereference_variable(lhs->components[i]);
writemask = 1;
} else {
new_lhs = ir->lhs->clone(mem_ctx, NULL);
writemask = 1 << i;
}
if (rhs) {
new_rhs =
new(mem_ctx) ir_dereference_variable(rhs->components[rhs_chan]);
} else {
new_rhs = new(mem_ctx) ir_swizzle(ir->rhs->clone(mem_ctx, NULL),
rhs_chan, 0, 0, 0, 1);
}
ir->insert_before(new(mem_ctx) ir_assignment(new_lhs,
new_rhs,
NULL, writemask));
rhs_chan++;
}
ir->remove();
} else if (lhs) {
void *mem_ctx = lhs->mem_ctx;
int elem = -1;
switch (ir->write_mask) {
case (1 << 0):
elem = 0;
break;
case (1 << 1):
elem = 1;
break;
case (1 << 2):
elem = 2;
break;
case (1 << 3):
elem = 3;
break;
default:
ir->fprint(stderr);
unreachable("not reached: non-channelwise dereference of LHS.");
}
ir->lhs = new(mem_ctx) ir_dereference_variable(lhs->components[elem]);
ir->write_mask = (1 << 0);
handle_rvalue(&ir->rhs);
} else {
handle_rvalue(&ir->rhs);
}
handle_rvalue(&ir->condition);
return visit_continue;
}
bool
brw_do_vector_splitting(exec_list *instructions)
{
ir_vector_reference_visitor refs;
visit_list_elements(&refs, instructions);
/* Trim out variables we can't split. */
foreach_in_list_safe(variable_entry, entry, &refs.variable_list) {
if (debug) {
fprintf(stderr, "vector %s@%p: whole_access %d\n",
entry->var->name, (void *) entry->var,
entry->whole_vector_access);
}
if (entry->whole_vector_access) {
entry->remove();
}
}
if (refs.variable_list.is_empty())
return false;
void *mem_ctx = ralloc_context(NULL);
/* Replace the decls of the vectors to be split with their split
* components.
*/
foreach_in_list(variable_entry, entry, &refs.variable_list) {
const struct glsl_type *type;
type = glsl_type::get_instance(entry->var->type->base_type, 1, 1);
entry->mem_ctx = ralloc_parent(entry->var);
for (unsigned int i = 0; i < entry->var->type->vector_elements; i++) {
char *const name = ir_variable::temporaries_allocate_names
? ralloc_asprintf(mem_ctx, "%s_%c",
entry->var->name,
"xyzw"[i])
: NULL;
entry->components[i] = new(entry->mem_ctx) ir_variable(type, name,
ir_var_temporary);
ralloc_free(name);
entry->var->insert_before(entry->components[i]);
}
entry->var->remove();
}
ir_vector_splitting_visitor split(&refs.variable_list);
visit_list_elements(&split, instructions);
ralloc_free(mem_ctx);
return true;
}