2 * This file is part of libFirm.
3 * Copyright (C) 2012 University of Karlsruhe.
8 * @brief Common functions for chordal register allocation.
9 * @author Sebastian Hack
14 #include "bechordal_common.h"
21 #include "bechordal.h"
22 #include "bechordal_t.h"
33 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
35 static inline border_t *border_add(be_chordal_env_t *const env, struct list_head *const head, ir_node *const irn, unsigned const step, unsigned const is_def, unsigned const is_real)
37 border_t *const b = OALLOC(&env->obst, border_t);
42 list_add_tail(&b->list, head);
43 DBG((dbg, LEVEL_5, "\t\t%s adding %+F, step: %d\n", is_def ? "def" : "use", irn, step));
48 void create_borders(ir_node *block, void *env_ptr)
50 /* Convenience macro for a def */
51 #define border_def(irn, step, real) \
52 border_add(env, head, irn, step, 1, real)
54 /* Convenience macro for a use */
55 #define border_use(irn, step, real) \
56 border_add(env, head, irn, step, 0, real)
58 be_chordal_env_t *const env = (be_chordal_env_t*)env_ptr;
61 struct list_head *head;
63 /* Set up the border list in the block info */
64 head = OALLOC(&env->obst, struct list_head);
66 assert(pmap_get(struct list_head, env->border_heads, block) == NULL);
67 pmap_insert(env->border_heads, block, head);
70 ir_nodeset_init(&live);
72 be_lv_t *const lv = be_get_irg_liveness(env->irg);
75 * Make final uses of all values live out of the block.
76 * They are necessary to build up real intervals.
78 be_lv_foreach_cls(lv, block, be_lv_state_end, env->cls, irn) {
79 DB((dbg, LEVEL_3, "\tMaking live: %+F\n", irn));
80 ir_nodeset_insert(&live, irn);
81 border_use(irn, step, 0);
86 * Determine the last uses of a value inside the block, since they are
87 * relevant for the interval borders.
89 sched_foreach_reverse(block, irn) {
93 DB((dbg, LEVEL_1, "\tinsn: %+F\n", irn));
95 be_foreach_definition(irn, env->cls, def, req,
97 * If the node defines some value, which can put into a
98 * register of the current class, make a border for it.
100 ir_nodeset_remove(&live, def);
101 border_def(def, step, 1);
104 /* Examine the uses. */
105 be_foreach_use(irn, env->cls, in_req_, op, op_req_,
106 const char *msg = "-";
108 if (ir_nodeset_insert(&live, op)) {
109 border_use(op, step, 1);
113 DB((dbg, LEVEL_4, "\t\t%s pos: %d, use: %+F\n", msg, i_, op));
118 foreach_ir_nodeset(&live, irn, iter) {
119 assert(be_is_live_in(lv, block, irn) ^ (is_Phi(irn) && get_nodes_block(irn) == block));
120 border_def(irn, step, get_nodes_block(irn) == block);
123 ir_nodeset_destroy(&live);
126 ir_node *pre_process_constraints(be_chordal_env_t *env, be_insn_t **the_insn)
128 be_insn_t *insn = *the_insn;
131 * Make the Perm, recompute liveness and re-scan the insn since the
132 * in operands are now the Projs of the Perm.
134 ir_node *const irn = insn->irn;
135 ir_node *const perm = insert_Perm_before(env->irg, env->cls, irn);
137 /* Registers are propagated by insert_Perm_before(). Clean them here! */
141 stat_ev_int("constr_perm", get_irn_arity(perm));
144 * We also have to re-build the insn since the input operands are now the Projs of
145 * the Perm. Recomputing liveness is also a good idea if a Perm is inserted, since
146 * the live sets may change.
148 obstack_free(&env->obst, insn);
149 *the_insn = insn = be_scan_insn(env, irn);
151 /* Copy the input constraints of the irn to the Perm as output
152 * constraints. Succeeding phases (coalescing) will need that. */
153 for (int i = 0, n = get_irn_arity(irn); i != n; ++i) {
154 ir_node *const proj = get_irn_n(irn, i);
155 /* Note that the predecessor is not necessarily a Proj of the Perm,
156 * since ignore-nodes are not Perm'ed. */
157 if (!is_Proj(proj) || get_Proj_pred(proj) != perm)
159 /* FIXME: Only setting the constraints, when the register requirement is
160 * limited, is a hack. It will break when multiple differently constrained
161 * inputs use the same value. */
162 arch_register_req_t const *const req = arch_get_irn_register_req_in(irn, i);
163 if (!arch_register_req_is(req, limited))
165 be_set_constr_out(perm, get_Proj_proj(proj), req);
171 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_chordal_common)
172 void be_init_chordal_common(void)
174 FIRM_DBG_REGISTER(dbg, "firm.be.chordal_common");