/**
* This function returns the last definition of a value. In case
* this value was last defined in a previous block, Phi nodes are
* inserted. If the part of the firm graph containing the definition
* is not yet constructed, a dummy Phi node is returned.
*
* @param block the current block
* @param pos the value number of the value searched
* @param mode the mode of this value (needed for Phi construction)
*/
static ir_node *get_r_value_internal(ir_node *block, int pos, ir_mode *mode)
{
ir_node *res = block->attr.block.graph_arr[pos];
if (res != NULL)
return res;
/* in a matured block we can immediately determine the phi arguments */
if (get_Block_matured(block)) {
ir_graph *const irg = get_irn_irg(block);
int const arity = get_irn_arity(block);
/* no predecessors: use unknown value */
if (arity == 0) {
if (block == get_irg_start_block(irg)) {
if (default_initialize_local_variable != NULL) {
ir_node *rem = get_r_cur_block(irg);
set_r_cur_block(irg, block);
res = default_initialize_local_variable(irg, mode, pos - 1);
set_r_cur_block(irg, rem);
} else {
res = new_r_Unknown(irg, mode);
}
} else {
goto bad; /* unreachable block, use Bad */
}
/* one predecessor just use its value */
} else if (arity == 1) {
ir_node *cfgpred = get_Block_cfgpred(block, 0);
if (is_Bad(cfgpred)) {
bad:
res = new_r_Bad(irg, mode);
} else {
ir_node *cfgpred_block = get_nodes_block(cfgpred);
res = get_r_value_internal(cfgpred_block, pos, mode);
}
} else {
/* multiple predecessors construct Phi */
res = new_rd_Phi0(NULL, block, mode, pos);
/* enter phi0 into our variable value table to break cycles
* arising from set_phi_arguments */
block->attr.block.graph_arr[pos] = res;
res = set_phi_arguments(res, pos);
}
} else {
/* in case of immature block we have to keep a Phi0 */
res = new_rd_Phi0(NULL, block, mode, pos);
/* enqueue phi so we can set arguments once the block matures */
res->attr.phi.next = block->attr.block.phis;
block->attr.block.phis = res;
}
block->attr.block.graph_arr[pos] = res;
return res;
}
static ir_graph *new_r_ir_graph(ir_entity *ent, int n_loc)
{
ir_graph *const res = alloc_graph();
/* Inform statistics here, as blocks will be already built on this graph. */
hook_new_graph(res, ent);
/* graphs are in construction mode by default */
add_irg_constraints(res, IR_GRAPH_CONSTRAINT_CONSTRUCTION);
irg_set_nloc(res, n_loc);
res->irg_pinned_state = op_pin_state_pinned;
res->callee_info_state = irg_callee_info_none;
res->mem_disambig_opt = aa_opt_inherited;
/*-- Type information for the procedure of the graph --*/
res->ent = ent;
if (ent)
set_entity_irg(ent, res);
/*-- a class type so that it can contain "inner" methods as in Pascal. --*/
res->frame_type = new_type_frame();
/* the Anchor node must be created first */
res->anchor = new_r_Anchor(res);
/*-- Nodes needed in every graph --*/
set_irg_end_block(res, new_r_immBlock(res));
set_irg_end(res, new_r_End(res, 0, NULL));
ir_node *const start_block = new_r_Block_noopt(res, 0, NULL);
set_irg_start_block(res, start_block);
set_irg_no_mem(res, new_r_NoMem(res));
res->index = get_irp_new_irg_idx();
#ifdef DEBUG_libfirm
res->graph_nr = get_irp_new_node_nr();
#endif
set_r_cur_block(res, start_block);
return res;
}