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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
*
* 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_tess_level.cpp
*
* This pass accounts for the difference between the way gl_TessLevelOuter
* and gl_TessLevelInner is declared in standard GLSL (as an array of
* floats), and the way it is frequently implemented in hardware (as a vec4
* and vec2).
*
* The declaration of gl_TessLevel* is replaced with a declaration
* of gl_TessLevel*MESA, and any references to gl_TessLevel* are
* translated to refer to gl_TessLevel*MESA with the appropriate
* swizzling of array indices. For instance:
*
* gl_TessLevelOuter[i]
*
* is translated into:
*
* gl_TessLevelOuterMESA[i]
*
* Since some hardware may not internally represent gl_TessLevel* as a pair
* of vec4's, this lowering pass is optional. To enable it, set the
* LowerTessLevel flag in gl_shader_compiler_options to true.
*/
#include "glsl_symbol_table.h"
#include "ir_rvalue_visitor.h"
#include "ir.h"
#include "program/prog_instruction.h" /* For WRITEMASK_* */
#include "main/mtypes.h"
namespace {
class lower_tess_level_visitor : public ir_rvalue_visitor {
public:
explicit lower_tess_level_visitor(gl_shader_stage shader_stage)
: progress(false), old_tess_level_outer_var(NULL),
old_tess_level_inner_var(NULL), new_tess_level_outer_var(NULL),
new_tess_level_inner_var(NULL), shader_stage(shader_stage)
{
}
virtual ir_visitor_status visit(ir_variable *);
bool is_tess_level_array(ir_rvalue *ir);
ir_rvalue *lower_tess_level_array(ir_rvalue *ir);
virtual ir_visitor_status visit_leave(ir_assignment *);
void visit_new_assignment(ir_assignment *ir);
virtual ir_visitor_status visit_leave(ir_call *);
virtual void handle_rvalue(ir_rvalue **rvalue);
void fix_lhs(ir_assignment *);
bool progress;
/**
* Pointer to the declaration of gl_TessLevel*, if found.
*/
ir_variable *old_tess_level_outer_var;
ir_variable *old_tess_level_inner_var;
/**
* Pointer to the newly-created gl_TessLevel*MESA variables.
*/
ir_variable *new_tess_level_outer_var;
ir_variable *new_tess_level_inner_var;
/**
* Type of shader we are compiling (e.g. MESA_SHADER_TESS_CTRL)
*/
const gl_shader_stage shader_stage;
};
} /* anonymous namespace */
/**
* Replace any declaration of gl_TessLevel* as an array of floats with a
* declaration of gl_TessLevel*MESA as a vec4.
*/
ir_visitor_status
lower_tess_level_visitor::visit(ir_variable *ir)
{
if ((!ir->name) ||
((strcmp(ir->name, "gl_TessLevelInner") != 0) &&
(strcmp(ir->name, "gl_TessLevelOuter") != 0)))
return visit_continue;
assert (ir->type->is_array());
if (strcmp(ir->name, "gl_TessLevelOuter") == 0) {
if (this->old_tess_level_outer_var)
return visit_continue;
old_tess_level_outer_var = ir;
assert(ir->type->fields.array == glsl_type::float_type);
/* Clone the old var so that we inherit all of its properties */
new_tess_level_outer_var = ir->clone(ralloc_parent(ir), NULL);
/* And change the properties that we need to change */
new_tess_level_outer_var->name = ralloc_strdup(new_tess_level_outer_var,
"gl_TessLevelOuterMESA");
new_tess_level_outer_var->type = glsl_type::vec4_type;
new_tess_level_outer_var->data.max_array_access = 0;
ir->replace_with(new_tess_level_outer_var);
} else if (strcmp(ir->name, "gl_TessLevelInner") == 0) {
if (this->old_tess_level_inner_var)
return visit_continue;
old_tess_level_inner_var = ir;
assert(ir->type->fields.array == glsl_type::float_type);
/* Clone the old var so that we inherit all of its properties */
new_tess_level_inner_var = ir->clone(ralloc_parent(ir), NULL);
/* And change the properties that we need to change */
new_tess_level_inner_var->name = ralloc_strdup(new_tess_level_inner_var,
"gl_TessLevelInnerMESA");
new_tess_level_inner_var->type = glsl_type::vec2_type;
new_tess_level_inner_var->data.max_array_access = 0;
ir->replace_with(new_tess_level_inner_var);
} else {
assert(0);
}
this->progress = true;
return visit_continue;
}
/**
* Determine whether the given rvalue describes an array of floats that
* needs to be lowered to a vec4; that is, determine whether it
* matches one of the following patterns:
*
* - gl_TessLevelOuter
* - gl_TessLevelInner
*/
bool
lower_tess_level_visitor::is_tess_level_array(ir_rvalue *ir)
{
if (!ir->type->is_array())
return false;
if (ir->type->fields.array != glsl_type::float_type)
return false;
if (this->old_tess_level_outer_var) {
if (ir->variable_referenced() == this->old_tess_level_outer_var)
return true;
}
if (this->old_tess_level_inner_var) {
if (ir->variable_referenced() == this->old_tess_level_inner_var)
return true;
}
return false;
}
/**
* If the given ir satisfies is_tess_level_array(), return new ir
* representing its lowered equivalent. That is, map:
*
* - gl_TessLevelOuter => gl_TessLevelOuterMESA
* - gl_TessLevelInner => gl_TessLevelInnerMESA
*
* Otherwise return NULL.
*/
ir_rvalue *
lower_tess_level_visitor::lower_tess_level_array(ir_rvalue *ir)
{
if (!ir->type->is_array())
return NULL;
if (ir->type->fields.array != glsl_type::float_type)
return NULL;
ir_variable **new_var = NULL;
if (this->old_tess_level_outer_var) {
if (ir->variable_referenced() == this->old_tess_level_outer_var)
new_var = &this->new_tess_level_outer_var;
}
if (this->old_tess_level_inner_var) {
if (ir->variable_referenced() == this->old_tess_level_inner_var)
new_var = &this->new_tess_level_inner_var;
}
if (new_var == NULL)
return NULL;
assert(ir->as_dereference_variable());
return new(ralloc_parent(ir)) ir_dereference_variable(*new_var);
}
void
lower_tess_level_visitor::handle_rvalue(ir_rvalue **rv)
{
if (*rv == NULL)
return;
ir_dereference_array *const array_deref = (*rv)->as_dereference_array();
if (array_deref == NULL)
return;
/* Replace any expression that indexes one of the floats in gl_TessLevel*
* with an expression that indexes into one of the vec4's
* gl_TessLevel*MESA and accesses the appropriate component.
*/
ir_rvalue *lowered_vec4 =
this->lower_tess_level_array(array_deref->array);
if (lowered_vec4 != NULL) {
this->progress = true;
void *mem_ctx = ralloc_parent(array_deref);
ir_expression *const expr =
new(mem_ctx) ir_expression(ir_binop_vector_extract,
lowered_vec4,
array_deref->array_index);
*rv = expr;
}
}
void
lower_tess_level_visitor::fix_lhs(ir_assignment *ir)
{
if (ir->lhs->ir_type != ir_type_expression)
return;
void *mem_ctx = ralloc_parent(ir);
ir_expression *const expr = (ir_expression *) ir->lhs;
/* The expression must be of the form:
*
* (vector_extract gl_TessLevel*MESA, j).
*/
assert(expr->operation == ir_binop_vector_extract);
assert(expr->operands[0]->ir_type == ir_type_dereference_variable);
assert((expr->operands[0]->type == glsl_type::vec4_type) ||
(expr->operands[0]->type == glsl_type::vec2_type));
ir_dereference *const new_lhs = (ir_dereference *) expr->operands[0];
ir_constant *old_index_constant =
expr->operands[1]->constant_expression_value(mem_ctx);
if (!old_index_constant) {
ir->rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert,
expr->operands[0]->type,
new_lhs->clone(mem_ctx, NULL),
ir->rhs,
expr->operands[1]);
}
ir->set_lhs(new_lhs);
if (old_index_constant) {
/* gl_TessLevel* is being accessed via a constant index. Don't bother
* creating a vector insert op. Just use a write mask.
*/
ir->write_mask = 1 << old_index_constant->get_int_component(0);
} else {
ir->write_mask = (1 << expr->operands[0]->type->vector_elements) - 1;
}
}
/**
* Replace any assignment having a gl_TessLevel* (undereferenced) as
* its LHS or RHS with a sequence of assignments, one for each component of
* the array. Each of these assignments is lowered to refer to
* gl_TessLevel*MESA as appropriate.
*/
ir_visitor_status
lower_tess_level_visitor::visit_leave(ir_assignment *ir)
{
/* First invoke the base class visitor. This causes handle_rvalue() to be
* called on ir->rhs and ir->condition.
*/
ir_rvalue_visitor::visit_leave(ir);
if (this->is_tess_level_array(ir->lhs) ||
this->is_tess_level_array(ir->rhs)) {
/* LHS or RHS of the assignment is the entire gl_TessLevel* array.
* Since we are
* reshaping gl_TessLevel* from an array of floats to a
* vec4, this isn't going to work as a bulk assignment anymore, so
* unroll it to element-by-element assignments and lower each of them.
*
* Note: to unroll into element-by-element assignments, we need to make
* clones of the LHS and RHS. This is safe because expressions and
* l-values are side-effect free.
*/
void *ctx = ralloc_parent(ir);
int array_size = ir->lhs->type->array_size();
for (int i = 0; i < array_size; ++i) {
ir_dereference_array *new_lhs = new(ctx) ir_dereference_array(
ir->lhs->clone(ctx, NULL), new(ctx) ir_constant(i));
ir_dereference_array *new_rhs = new(ctx) ir_dereference_array(
ir->rhs->clone(ctx, NULL), new(ctx) ir_constant(i));
this->handle_rvalue((ir_rvalue **) &new_rhs);
/* Handle the LHS after creating the new assignment. This must
* happen in this order because handle_rvalue may replace the old LHS
* with an ir_expression of ir_binop_vector_extract. Since this is
* not a valide l-value, this will cause an assertion in the
* ir_assignment constructor to fail.
*
* If this occurs, replace the mangled LHS with a dereference of the
* vector, and replace the RHS with an ir_triop_vector_insert.
*/
ir_assignment *const assign = new(ctx) ir_assignment(new_lhs, new_rhs);
this->handle_rvalue((ir_rvalue **) &assign->lhs);
this->fix_lhs(assign);
this->base_ir->insert_before(assign);
}
ir->remove();
return visit_continue;
}
/* Handle the LHS as if it were an r-value. Normally
* rvalue_visit(ir_assignment *) only visits the RHS, but we need to lower
* expressions in the LHS as well.
*
* This may cause the LHS to get replaced with an ir_expression of
* ir_binop_vector_extract. If this occurs, replace it with a dereference
* of the vector, and replace the RHS with an ir_triop_vector_insert.
*/
handle_rvalue((ir_rvalue **)&ir->lhs);
this->fix_lhs(ir);
return rvalue_visit(ir);
}
/**
* Set up base_ir properly and call visit_leave() on a newly created
* ir_assignment node. This is used in cases where we have to insert an
* ir_assignment in a place where we know the hierarchical visitor won't see
* it.
*/
void
lower_tess_level_visitor::visit_new_assignment(ir_assignment *ir)
{
ir_instruction *old_base_ir = this->base_ir;
this->base_ir = ir;
ir->accept(this);
this->base_ir = old_base_ir;
}
/**
* If a gl_TessLevel* variable appears as an argument in an ir_call
* expression, replace it with a temporary variable, and make sure the ir_call
* is preceded and/or followed by assignments that copy the contents of the
* temporary variable to and/or from gl_TessLevel*. Each of these
* assignments is then lowered to refer to gl_TessLevel*MESA.
*/
ir_visitor_status
lower_tess_level_visitor::visit_leave(ir_call *ir)
{
void *ctx = ralloc_parent(ir);
const exec_node *formal_param_node = ir->callee->parameters.get_head_raw();
const exec_node *actual_param_node = ir->actual_parameters.get_head_raw();
while (!actual_param_node->is_tail_sentinel()) {
ir_variable *formal_param = (ir_variable *) formal_param_node;
ir_rvalue *actual_param = (ir_rvalue *) actual_param_node;
/* Advance formal_param_node and actual_param_node now so that we can
* safely replace actual_param with another node, if necessary, below.
*/
formal_param_node = formal_param_node->next;
actual_param_node = actual_param_node->next;
if (!this->is_tess_level_array(actual_param))
continue;
/* User is trying to pass a whole gl_TessLevel* array to a function
* call. Since we are reshaping gl_TessLevel* from an array of floats
* to a vec4, this isn't going to work anymore, so use a temporary
* array instead.
*/
ir_variable *temp = new(ctx) ir_variable(
actual_param->type, "temp_tess_level", ir_var_temporary);
this->base_ir->insert_before(temp);
actual_param->replace_with(
new(ctx) ir_dereference_variable(temp));
if (formal_param->data.mode == ir_var_function_in
|| formal_param->data.mode == ir_var_function_inout) {
/* Copy from gl_TessLevel* to the temporary before the call.
* Since we are going to insert this copy before the current
* instruction, we need to visit it afterwards to make sure it
* gets lowered.
*/
ir_assignment *new_assignment = new(ctx) ir_assignment(
new(ctx) ir_dereference_variable(temp),
actual_param->clone(ctx, NULL));
this->base_ir->insert_before(new_assignment);
this->visit_new_assignment(new_assignment);
}
if (formal_param->data.mode == ir_var_function_out
|| formal_param->data.mode == ir_var_function_inout) {
/* Copy from the temporary to gl_TessLevel* after the call.
* Since visit_list_elements() has already decided which
* instruction it's going to visit next, we need to visit
* afterwards to make sure it gets lowered.
*/
ir_assignment *new_assignment = new(ctx) ir_assignment(
actual_param->clone(ctx, NULL),
new(ctx) ir_dereference_variable(temp));
this->base_ir->insert_after(new_assignment);
this->visit_new_assignment(new_assignment);
}
}
return rvalue_visit(ir);
}
bool
lower_tess_level(gl_linked_shader *shader)
{
if ((shader->Stage != MESA_SHADER_TESS_CTRL) &&
(shader->Stage != MESA_SHADER_TESS_EVAL))
return false;
lower_tess_level_visitor v(shader->Stage);
visit_list_elements(&v, shader->ir);
if (v.new_tess_level_outer_var)
shader->symbols->add_variable(v.new_tess_level_outer_var);
if (v.new_tess_level_inner_var)
shader->symbols->add_variable(v.new_tess_level_inner_var);
return v.progress;
}