2 * This file is part of libFirm.
3 * Copyright (C) 2012 University of Karlsruhe.
8 * @brief Removal of unreachable methods.
9 * @author Hubert Schmid
14 * Entfernen von nicht erreichbaren (aufrufbaren) Methoden. Die Menge
15 * der nicht erreichbaren Methoden wird aus der Abschätzung der
16 * Aufrufrelation bestimmt.
33 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
36 * Walker: adds Call operations to a head's link list.
38 static void collect_call(ir_node *node, void *env)
40 ir_node *head = (ir_node*)env;
43 set_irn_link(node, get_irn_link(head));
44 set_irn_link(head, node);
48 /* garbage collect methods: mark and remove */
49 void gc_irgs(size_t n_keep, ir_entity ** keep_arr)
51 void * MARK = &MARK; /* @@@ gefaehrlich!!! Aber wir markieren hoechstens zu viele ... */
53 FIRM_DBG_REGISTER(dbg, "firm.opt.cgopt");
55 if (n_keep >= get_irp_n_irgs()) {
56 /* Shortcut. Obviously we have to keep all methods. */
60 DB((dbg, LEVEL_1, "dead method elimination\n"));
62 /* Mark entities that are alive. */
64 ir_entity **marked = NEW_ARR_F(ir_entity *, n_keep);
67 for (idx = 0; idx < n_keep; ++idx) {
68 marked[idx] = keep_arr[idx];
69 set_entity_link(marked[idx], MARK);
70 DB((dbg, LEVEL_1, " method %+F kept alive.\n", marked[idx]));
73 for (idx = 0; idx < ARR_LEN(marked); ++idx) {
74 ir_graph *irg = get_entity_irg(marked[idx]);
80 node = get_irg_end(irg);
83 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
84 irg_walk_graph(irg, firm_clear_link, collect_call, node);
87 for (node = (ir_node*)get_irn_link(node); node != NULL;
88 node = (ir_node*)get_irn_link(node)) {
89 for (size_t i = get_Call_n_callees(node); i > 0;) {
90 ir_entity *ent = get_Call_callee(node, --i);
92 if (get_entity_irg(ent) && get_entity_link(ent) != MARK) {
93 set_entity_link(ent, MARK);
94 ARR_APP1(ir_entity *, marked, ent);
96 DB((dbg, LEVEL_1, " method %+F can be called from Call %+F: kept alive.\n",
101 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
107 for (size_t i = get_irp_n_irgs(); i-- != 0;) {
108 ir_graph *irg = get_irp_irg(i);
109 ir_entity *ent = get_irg_entity(irg);
111 if (get_entity_link(ent) == MARK)
114 DB((dbg, LEVEL_1, " freeing method %+F\n", ent));
120 * Wrapper for running gc_irgs() as an ir_prog pass.
122 static void pass_wrapper(void)
124 ir_entity **keep_methods;
127 /* Analysis that finds the free methods,
128 i.e. methods that are dereferenced.
129 Optimizes polymorphic calls :-). */
130 arr_len = cgana(&keep_methods);
132 /* Remove methods that are never called. */
133 gc_irgs(arr_len, keep_methods);
138 ir_prog_pass_t *gc_irgs_pass(const char *name)
140 return def_prog_pass(name ? name : "cgana", pass_wrapper);