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) {
90 DB((dbg, LEVEL_1, "\tinsn: %+F\n", irn));
92 be_foreach_definition(irn, env->cls, def, req,
94 * If the node defines some value, which can put into a
95 * register of the current class, make a border for it.
97 ir_nodeset_remove(&live, def);
98 border_def(def, step, 1);
101 /* If the node is no phi node we can examine the uses. */
103 be_foreach_use(irn, env->cls, in_req_, op, op_req_,
104 const char *msg = "-";
106 if (ir_nodeset_insert(&live, op)) {
107 border_use(op, step, 1);
111 DB((dbg, LEVEL_4, "\t\t%s pos: %d, use: %+F\n", msg, i_, op));
117 /* Process live-ins last. In particular all Phis are handled before, so when
118 * iterating the borders the live-ins come before all Phis ("live-start"). */
119 foreach_ir_nodeset(&live, irn, iter) {
120 assert(be_is_live_in(lv, block, irn));
121 border_def(irn, step, 0);
124 ir_nodeset_destroy(&live);
127 ir_node *pre_process_constraints(be_chordal_env_t *env, be_insn_t **the_insn)
129 be_insn_t *insn = *the_insn;
132 * Make the Perm, recompute liveness and re-scan the insn since the
133 * in operands are now the Projs of the Perm.
135 ir_node *const irn = insn->irn;
136 ir_node *const perm = insert_Perm_before(env->irg, env->cls, irn);
138 /* Registers are propagated by insert_Perm_before(). Clean them here! */
142 stat_ev_int("constr_perm", get_irn_arity(perm));
145 * We also have to re-build the insn since the input operands are now the Projs of
146 * the Perm. Recomputing liveness is also a good idea if a Perm is inserted, since
147 * the live sets may change.
149 obstack_free(&env->obst, insn);
150 *the_insn = insn = be_scan_insn(env, irn);
152 /* Copy the input constraints of the irn to the Perm as output
153 * constraints. Succeeding phases (coalescing) will need that. */
154 for (int i = 0, n = get_irn_arity(irn); i != n; ++i) {
155 ir_node *const proj = get_irn_n(irn, i);
156 /* Note that the predecessor is not necessarily a Proj of the Perm,
157 * since ignore-nodes are not Perm'ed. */
158 if (!is_Proj(proj) || get_Proj_pred(proj) != perm)
160 /* FIXME: Only setting the constraints, when the register requirement is
161 * limited, is a hack. It will break when multiple differently constrained
162 * inputs use the same value. */
163 arch_register_req_t const *const req = arch_get_irn_register_req_in(irn, i);
164 if (!arch_register_req_is(req, limited))
166 be_set_constr_out(perm, get_Proj_proj(proj), req);
172 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_chordal_common)
173 void be_init_chordal_common(void)
175 FIRM_DBG_REGISTER(dbg, "firm.be.chordal_common");