/**
* If a 1D gl_ClipDistance 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_ClipDistance. Each of these
* assignments is then lowered to refer to gl_ClipDistanceMESA.
*
* We need to do a similar replacement for 2D gl_ClipDistance, however since
* it's an input, the only case we need to address is where a 1D slice of it
* is passed as an "in" parameter to an ir_call, e.g.:
*
* foo(gl_in[i].gl_ClipDistance)
*/
ir_visitor_status
lower_clip_distance_visitor::visit_leave(ir_call *ir)
{
void *ctx = ralloc_parent(ir);
const exec_node *formal_param_node = ir->callee->parameters.head;
const exec_node *actual_param_node = ir->actual_parameters.head;
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_clip_distance_vec8(actual_param)) {
/* User is trying to pass the whole 1D gl_ClipDistance array (or a 1D
* slice of a 2D gl_ClipDistance array) to a function call. Since we
* are reshaping gl_ClipDistance from an array of floats to an array
* of vec4's, this isn't going to work anymore, so use a temporary
* array instead.
*/
ir_variable *temp_clip_distance = new(ctx) ir_variable(
actual_param->type, "temp_clip_distance", ir_var_temporary, actual_param->get_precision());
this->base_ir->insert_before(temp_clip_distance);
actual_param->replace_with(
new(ctx) ir_dereference_variable(temp_clip_distance));
if (formal_param->data.mode == ir_var_function_in
|| formal_param->data.mode == ir_var_function_inout) {
/* Copy from gl_ClipDistance 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_clip_distance),
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_ClipDistance 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_clip_distance));
this->base_ir->insert_after(new_assignment);
this->visit_new_assignment(new_assignment);
}
}
}
return rvalue_visit(ir);
}
/**
* Replace any assignment having gl_ClipDistance (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_ClipDistanceMESA as
* appropriate.
*/
ir_visitor_status
lower_clip_distance_visitor::visit_leave(ir_assignment *ir)
{
ir_dereference_variable *lhs_var = ir->lhs->as_dereference_variable();
ir_dereference_variable *rhs_var = ir->rhs->as_dereference_variable();
if ((lhs_var && lhs_var->var == this->old_clip_distance_var)
|| (rhs_var && rhs_var->var == this->old_clip_distance_var)) {
/* LHS or RHS of the assignment is the entire gl_ClipDistance array.
* Since we are reshaping gl_ClipDistance from an array of floats to an
* array of vec4's, 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 = this->old_clip_distance_var->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);
}
