2 * Scheduling algorithms.
3 * Just a simple list scheduling algorithm is here.
5 * @author Sebastian Hack
24 #include "irprintf_t.h"
27 #include "besched_t.h"
29 #include "belistsched.h"
32 * Scheduling environment for the whole graph.
34 typedef struct _sched_env_t {
35 const ir_graph *irg; /**< The graph to schedule. */
36 const list_sched_selector_t *selector; /**< The node selector. */
37 void *selector_env; /**< A pointer to give to the selector. */
40 static ir_node *trivial_select(void *env, void *block_env, const struct list_head *sched_head,
41 int curr_time, pset *ready_set)
43 ir_node *res = pset_first(ready_set);
44 pset_break(ready_set);
48 static const list_sched_selector_t trivial_selector_struct = {
56 const list_sched_selector_t *trivial_selector = &trivial_selector_struct;
58 static void list_sched_block(ir_node *block, void *env_ptr);
60 void list_sched(ir_graph *irg, const list_sched_selector_t *selector)
64 memset(&env, 0, sizeof(env));
65 env.selector = selector;
66 env.selector_env = selector->init_graph ? selector->init_graph(irg) : NULL;
69 /* Normalize proj nodes. */
70 normalize_proj_nodes(irg);
72 /* Compute the outs */
73 if(get_irg_outs_state(irg) != outs_consistent)
77 //dump_ir_block_graph(irg, "-before-sched");
79 /* Schedule each single block. */
80 irg_block_walk_graph(irg, list_sched_block, NULL, &env);
82 if(selector->finish_graph)
83 selector->finish_graph(env.selector_env, irg);
88 * Environment for a block scheduler.
90 typedef struct _block_sched_env_t {
93 pset *already_scheduled;
95 firm_dbg_module_t *dbg;
101 * Checks, if a node is to appear in a schedule. Such nodes either
102 * consume real data (mode datab) or produce such.
103 * @param irn The node to check for.
104 * @return 1, if the node consumes/produces data, false if not.
106 static INLINE int to_appear_in_schedule(ir_node *irn)
110 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
111 ir_node *op = get_irn_n(irn, i);
112 if(mode_is_datab(get_irn_mode(op)))
116 return mode_is_datab(get_irn_mode(irn));
121 * Try to put a node in the ready set.
122 * @param env The block scheduler environment.
123 * @param irn The node to make ready.
124 * @return 1, if the node could be made ready, 0 else.
126 static INLINE int make_ready(block_sched_env_t *env, ir_node *irn)
130 /* Blocks cannot be scheduled. */
135 * Check, if the given ir node is in a different block as the
136 * currently scheduled one. If that is so, don't make the node ready.
138 if(env->block != get_nodes_block(irn))
141 for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
142 ir_node *op = get_irn_n(irn, i);
144 /* If the operand is local to the scheduled block and not yet
145 * scheduled, this nodes cannot be made ready, so exit. */
146 if(!pset_find_ptr(env->already_scheduled, op) && get_nodes_block(op) == env->block)
150 DBG((env->dbg, LEVEL_2, "\tmaking ready: %n\n", irn));
151 pset_insert_ptr(env->ready_set, irn);
157 * Check, if a node is ready in a block schedule.
158 * @param env The block schedule environment.
159 * @param irn The node to check for.
160 * @return 1 if the node was ready, 0 if not.
162 #define is_ready(env,irn) \
163 (pset_find_ptr((env)->ready_set, irn) != NULL)
166 * Check, if a node has already been schedules.
167 * @param env The block schedule environment.
168 * @param irn The node to check for.
169 * @return 1 if the node was already scheduled, 0 if not.
171 #define is_scheduled(env,irn) \
172 (pset_find_ptr((env)->already_scheduled, irn) != NULL)
175 * Try, to make all users of a node ready.
176 * In fact, a usage node can only be made ready, if all its operands
177 * have already been scheduled yet. This is checked my make_ready().
178 * @param env The block schedule environment.
179 * @param irn The node, which usages (successors) are to be made ready.
181 static INLINE void make_users_ready(block_sched_env_t *env, ir_node *irn)
185 for(i = 0, n = get_irn_n_outs(irn); i < n; ++i) {
186 ir_node *user = get_irn_out(irn, i);
188 make_ready(env, user);
193 * Compare to nodes using pointer equality.
194 * @param p1 Node one.
195 * @param p2 Node two.
196 * @return 0 if they are identical.
198 static int node_cmp_func(const void *p1, const void *p2)
204 * Append an instruction to a schedule.
205 * @param env The block scheduleing environment.
206 * @param irn The node to add to the schedule.
207 * @return The given node.
209 static ir_node *add_to_sched(block_sched_env_t *env, ir_node *irn)
211 /* If the node consumes/produces data, it is appended to the schedule
212 * list, otherwise, it is not put into the list */
213 if(to_appear_in_schedule(irn)) {
214 sched_info_t *info = get_irn_sched_info(irn);
215 INIT_LIST_HEAD(&info->list);
216 info->time_step = env->curr_time;
217 sched_add(env->block, irn);
219 DBG((env->dbg, LEVEL_2, "\tadding %n\n", irn));
222 /* Insert the node in the set of all already scheduled nodes. */
223 pset_insert_ptr(env->already_scheduled, irn);
225 /* Remove the node from the ready set */
226 if(pset_find_ptr(env->ready_set, irn))
227 pset_remove_ptr(env->ready_set, irn);
234 * Add the proj nodes of a tuple-mode irn to the schedule immediately
235 * after the tuple-moded irn. By pinning the projs after the irn, no
236 * other nodes can create a new lifetime between the tuple-moded irn and
237 * one of its projs. This should render a realistic image of a
238 * tuple-moded irn, which in fact models a node which defines multiple
241 * @param irn The tuple-moded irn.
242 * @param list The schedule list to append all the projs.
243 * @param time The time step to which the irn and all its projs are
245 * @param obst The obstack the scheduling data structures shall be
247 * @param ready_set The ready set of the list scheduler.
248 * @param already_scheduled A set containing all nodes already
251 static void add_tuple_projs(block_sched_env_t *env, ir_node *irn)
254 assert(get_irn_mode(irn) == mode_T && "Mode of node must be tuple");
256 for(i = 0, n = get_irn_n_outs(irn); i < n; ++i) {
257 ir_node *out = get_irn_out(irn, i);
259 assert(is_Proj(out) && "successor of a modeT node must be a proj");
261 if(get_irn_mode(out) == mode_T)
262 add_tuple_projs(env, out);
264 add_to_sched(env, out);
265 make_users_ready(env, out);
271 * Perform list scheduling on a block.
273 * Note, that the caller must compute a linked list of nodes in the block
274 * using the link field before calling this function.
276 * Also the outs must have been computed.
278 * @param block The block node.
279 * @param env Schedulting environment.
281 static void list_sched_block(ir_node *block, void *env_ptr)
283 void *block_env = NULL;
284 sched_env_t *env = env_ptr;
285 block_sched_env_t be;
286 const list_sched_selector_t *selector = env->selector;
291 sched_info_t *info = get_irn_sched_info(block);
293 /* Initialize the block's list head that will hold the schedule. */
294 INIT_LIST_HEAD(&info->list);
296 /* Initialize the block scheduling environment */
297 be.dbg = firm_dbg_register("firm.be.sched");
300 be.ready_set = new_pset(node_cmp_func, get_irn_n_outs(block));
301 be.already_scheduled = new_pset(node_cmp_func, get_irn_n_outs(block));
303 if(selector->init_block)
304 block_env = selector->init_block(env->selector_env, block);
306 DBG((be.dbg, LEVEL_1, "scheduling %n\n", block));
308 /* Then one can add all nodes are ready to the set. */
309 for(i = 0, n = get_irn_n_outs(block); i < n; ++i) {
310 ir_node *irn = get_irn_out(block, i);
312 /* Skip the end node because of keepalive edges. */
313 if(get_irn_opcode(irn) == iro_End)
316 /* Phi functions are scheduled immediately, since they only transfer
317 * data flow from the predecessors to this block. */
319 add_to_sched(&be, irn);
320 make_users_ready(&be, irn);
324 /* Other nodes must have all operands in other blocks to be made
329 /* Check, if the operands of a node are not local to this block */
330 for(j = 0, m = get_irn_arity(irn); j < m; ++j) {
331 ir_node *operand = get_irn_n(irn, j);
333 if(get_nodes_block(operand) == block) {
339 /* Make the node ready, if all operands live in a foreign block */
341 DBG((be.dbg, LEVEL_2, "\timmediately ready: %n\n", irn));
342 make_ready(&be, irn);
347 /* Increase the time, if some phi functions have been scheduled */
348 be.curr_time += phi_seen;
350 while(pset_count(be.ready_set) > 0) {
351 DBG((be.dbg, LEVEL_2, "\tready set: %*n\n", pset_iterator, be.ready_set));
353 /* select a node to be scheduled and check if it was ready */
354 irn = selector->select(env->selector_env, block_env, &info->list, be.curr_time, be.ready_set);
356 DBG((be.dbg, LEVEL_3, "\tpicked node %n\n", irn));
358 /* Add the node to the schedule. */
359 add_to_sched(&be, irn);
361 if(get_irn_mode(irn) == mode_T)
362 add_tuple_projs(&be, irn);
364 make_users_ready(&be, irn);
366 /* Increase the time step. */
369 /* remove the scheduled node from the ready list. */
370 if(pset_find_ptr(be.ready_set, irn))
371 pset_remove_ptr(be.ready_set, irn);
374 if(selector->finish_block)
375 selector->finish_block(env->selector_env, block_env, block);
377 del_pset(be.ready_set);
378 del_pset(be.already_scheduled);