/*
* 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 ir_set_program_inouts.cpp
*
* Sets the InputsRead and OutputsWritten of Mesa programs.
*
* Additionally, for fragment shaders, sets the InterpQualifier array, the
* IsCentroid and IsSample bitfields, and the UsesDFdy flag.
*
* Mesa programs (gl_program, not gl_shader_program) have a set of
* flags indicating which varyings are read and written. Computing
* which are actually read from some sort of backend code can be
* tricky when variable array indexing involved. So this pass
* provides support for setting InputsRead and OutputsWritten right
* from the GLSL IR.
*/
#include "main/core.h" /* for struct gl_program */
#include "ir.h"
#include "ir_visitor.h"
#include "glsl_types.h"
namespace {
class ir_set_program_inouts_visitor : public ir_hierarchical_visitor {
public:
ir_set_program_inouts_visitor(struct gl_program *prog,
gl_shader_stage shader_stage)
{
this->prog = prog;
this->shader_stage = shader_stage;
}
~ir_set_program_inouts_visitor()
{
}
virtual ir_visitor_status visit_enter(ir_dereference_array *);
virtual ir_visitor_status visit_enter(ir_function_signature *);
virtual ir_visitor_status visit_enter(ir_expression *);
virtual ir_visitor_status visit_enter(ir_discard *);
virtual ir_visitor_status visit_enter(ir_texture *);
virtual ir_visitor_status visit(ir_dereference_variable *);
private:
void mark_whole_variable(ir_variable *var);
bool try_mark_partial_variable(ir_variable *var, ir_rvalue *index);
struct gl_program *prog;
gl_shader_stage shader_stage;
};
} /* anonymous namespace */
static inline bool
is_shader_inout(ir_variable *var)
{
return var->data.mode == ir_var_shader_in ||
var->data.mode == ir_var_shader_out ||
var->data.mode == ir_var_system_value;
}
static inline bool
is_dual_slot(ir_variable *var)
{
const glsl_type *type = var->type->without_array();
return type == glsl_type::dvec4_type || type == glsl_type::dvec3_type;
}
static void
mark(struct gl_program *prog, ir_variable *var, int offset, int len,
bool is_fragment_shader)
{
/* As of GLSL 1.20, varyings can only be floats, floating-point
* vectors or matrices, or arrays of them. For Mesa programs using
* InputsRead/OutputsWritten, everything but matrices uses one
* slot, while matrices use a slot per column. Presumably
* something doing a more clever packing would use something other
* than InputsRead/OutputsWritten.
*/
for (int i = 0; i < len; i++) {
bool dual_slot = is_dual_slot(var);
int idx = var->data.location + var->data.index + offset + i;
GLbitfield64 bitfield = BITFIELD64_BIT(idx);
if (var->data.mode == ir_var_shader_in) {
prog->InputsRead |= bitfield;
if (dual_slot)
prog->DoubleInputsRead |= bitfield;
if (is_fragment_shader) {
gl_fragment_program *fprog = (gl_fragment_program *) prog;
fprog->InterpQualifier[idx] =
(glsl_interp_qualifier) var->data.interpolation;
if (var->data.centroid)
fprog->IsCentroid |= bitfield;
if (var->data.sample)
fprog->IsSample |= bitfield;
}
} else if (var->data.mode == ir_var_system_value) {
prog->SystemValuesRead |= bitfield;
} else {
assert(var->data.mode == ir_var_shader_out);
prog->OutputsWritten |= bitfield;
}
}
}
/**
* Mark an entire variable as used. Caller must ensure that the variable
* represents a shader input or output.
*/
void
ir_set_program_inouts_visitor::mark_whole_variable(ir_variable *var)
{
const glsl_type *type = var->type;
if (this->shader_stage == MESA_SHADER_GEOMETRY &&
var->data.mode == ir_var_shader_in && type->is_array()) {
type = type->fields.array;
}
mark(this->prog, var, 0, type->count_attribute_slots(),
this->shader_stage == MESA_SHADER_FRAGMENT);
}
/* Default handler: Mark all the locations in the variable as used. */
ir_visitor_status
ir_set_program_inouts_visitor::visit(ir_dereference_variable *ir)
{
if (!is_shader_inout(ir->var))
return visit_continue;
mark_whole_variable(ir->var);
return visit_continue;
}
/**
* Try to mark a portion of the given variable as used. Caller must ensure
* that the variable represents a shader input or output which can be indexed
* into in array fashion (an array or matrix). For the purpose of geometry
* shader inputs (which are always arrays*), this means that the array element
* must be something that can be indexed into in array fashion.
*
* *Except gl_PrimitiveIDIn, as noted below.
*
* If the index can't be interpreted as a constant, or some other problem
* occurs, then nothing will be marked and false will be returned.
*/
bool
ir_set_program_inouts_visitor::try_mark_partial_variable(ir_variable *var,
ir_rvalue *index)
{
const glsl_type *type = var->type;
if (this->shader_stage == MESA_SHADER_GEOMETRY &&
var->data.mode == ir_var_shader_in) {
/* The only geometry shader input that is not an array is
* gl_PrimitiveIDIn, and in that case, this code will never be reached,
* because gl_PrimitiveIDIn can't be indexed into in array fashion.
*/
assert(type->is_array());
type = type->fields.array;
}
/* The code below only handles:
*
* - Indexing into matrices
* - Indexing into arrays of (matrices, vectors, or scalars)
*
* All other possibilities are either prohibited by GLSL (vertex inputs and
* fragment outputs can't be structs) or should have been eliminated by
* lowering passes (do_vec_index_to_swizzle() gets rid of indexing into
* vectors, and lower_packed_varyings() gets rid of structs that occur in
* varyings).
*/
if (!(type->is_matrix() ||
(type->is_array() &&
(type->fields.array->is_numeric() ||
type->fields.array->is_boolean())))) {
assert(!"Unexpected indexing in ir_set_program_inouts");
/* For safety in release builds, in case we ever encounter unexpected
* indexing, give up and let the caller mark the whole variable as used.
*/
return false;
}
ir_constant *index_as_constant = index->as_constant();
if (!index_as_constant)
return false;
unsigned elem_width;
unsigned num_elems;
if (type->is_array()) {
num_elems = type->length;
if (type->fields.array->is_matrix())
elem_width = type->fields.array->matrix_columns;
else
elem_width = 1;
} else {
num_elems = type->matrix_columns;
elem_width = 1;
}
if (index_as_constant->value.u[0] >= num_elems) {
/* Constant index outside the bounds of the matrix/array. This could
* arise as a result of constant folding of a legal GLSL program.
*
* Even though the spec says that indexing outside the bounds of a
* matrix/array results in undefined behaviour, we don't want to pass
* out-of-range values to mark() (since this could result in slots that
* don't exist being marked as used), so just let the caller mark the
* whole variable as used.
*/
return false;
}
mark(this->prog, var, index_as_constant->value.u[0] * elem_width,
elem_width, this->shader_stage == MESA_SHADER_FRAGMENT);
return true;
}
ir_visitor_status
ir_set_program_inouts_visitor::visit_enter(ir_dereference_array *ir)
{
/* Note: for geometry shader inputs, lower_named_interface_blocks may
* create 2D arrays, so we need to be able to handle those. 2D arrays
* shouldn't be able to crop up for any other reason.
*/
if (ir_dereference_array * const inner_array =
ir->array->as_dereference_array()) {
/* ir => foo[i][j]
* inner_array => foo[i]
*/
if (ir_dereference_variable * const deref_var =
inner_array->array->as_dereference_variable()) {
if (this->shader_stage == MESA_SHADER_GEOMETRY &&
deref_var->var->data.mode == ir_var_shader_in) {
/* foo is a geometry shader input, so i is the vertex, and j the
* part of the input we're accessing.
*/
if (try_mark_partial_variable(deref_var->var, ir->array_index))
{
/* We've now taken care of foo and j, but i might contain a
* subexpression that accesses shader inputs. So manually
* visit i and then continue with the parent.
*/
inner_array->array_index->accept(this);
return visit_continue_with_parent;
}
}
}
} else if (ir_dereference_variable * const deref_var =
ir->array->as_dereference_variable()) {
/* ir => foo[i], where foo is a variable. */
if (this->shader_stage == MESA_SHADER_GEOMETRY &&
deref_var->var->data.mode == ir_var_shader_in) {
/* foo is a geometry shader input, so i is the vertex, and we're
* accessing the entire input.
*/
mark_whole_variable(deref_var->var);
/* We've now taken care of foo, but i might contain a subexpression
* that accesses shader inputs. So manually visit i and then
* continue with the parent.
*/
ir->array_index->accept(this);
return visit_continue_with_parent;
} else if (is_shader_inout(deref_var->var)) {
/* foo is a shader input/output, but not a geometry shader input,
* so i is the part of the input we're accessing.
*/
if (try_mark_partial_variable(deref_var->var, ir->array_index))
return visit_continue_with_parent;
}
}
/* The expression is something we don't recognize. Just visit its
* subexpressions.
*/
return visit_continue;
}
ir_visitor_status
ir_set_program_inouts_visitor::visit_enter(ir_function_signature *ir)
{
/* We don't want to descend into the function parameters and
* consider them as shader inputs or outputs.
*/
visit_list_elements(this, &ir->body);
return visit_continue_with_parent;
}
ir_visitor_status
ir_set_program_inouts_visitor::visit_enter(ir_expression *ir)
{
if (this->shader_stage == MESA_SHADER_FRAGMENT &&
(ir->operation == ir_unop_dFdy ||
ir->operation == ir_unop_dFdy_coarse ||
ir->operation == ir_unop_dFdy_fine)) {
gl_fragment_program *fprog = (gl_fragment_program *) prog;
fprog->UsesDFdy = true;
}
return visit_continue;
}
ir_visitor_status
ir_set_program_inouts_visitor::visit_enter(ir_discard *)
{
/* discards are only allowed in fragment shaders. */
assert(this->shader_stage == MESA_SHADER_FRAGMENT);
gl_fragment_program *fprog = (gl_fragment_program *) prog;
fprog->UsesKill = true;
return visit_continue;
}
ir_visitor_status
ir_set_program_inouts_visitor::visit_enter(ir_texture *ir)
{
if (ir->op == ir_tg4)
prog->UsesGather = true;
return visit_continue;
}
void
do_set_program_inouts(exec_list *instructions, struct gl_program *prog,
gl_shader_stage shader_stage)
{
ir_set_program_inouts_visitor v(prog, shader_stage);
prog->InputsRead = 0;
prog->OutputsWritten = 0;
prog->SystemValuesRead = 0;
if (shader_stage == MESA_SHADER_FRAGMENT) {
gl_fragment_program *fprog = (gl_fragment_program *) prog;
memset(fprog->InterpQualifier, 0, sizeof(fprog->InterpQualifier));
fprog->IsCentroid = 0;
fprog->IsSample = 0;
fprog->UsesDFdy = false;
fprog->UsesKill = false;
}
visit_list_elements(&v, instructions);
}