#define DBG_SLOTS 32
#define DBG_TRACE 64
#define DBG_WORKSET 128
-#define DEBUG_LVL 0 //(DBG_START | DBG_DECIDE | DBG_WSETS | DBG_FIX | DBG_SPILL)
DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
-typedef struct _workset_t workset_t;
+/**
+ * An association between a node and a point in time.
+ */
+typedef struct _loc_t {
+ ir_node *irn; /**< A node. */
+ unsigned time; /**< A use time (see beuses.h). */
+} loc_t;
+
+typedef struct _workset_t {
+ int len; /**< current length */
+ loc_t vals[0]; /**< inlined array of the values/distances in this working set */
+} workset_t;
typedef struct _belady_env_t {
struct obstack ob;
+ const be_chordal_env_t *cenv;
const arch_env_t *arch;
const arch_register_class_t *cls;
int n_regs; /** number of regs in this reg-class */
spill_env_t *senv; /**< see bespill.h */
} belady_env_t;
-struct _workset_t {
- int len; /**< current length */
- loc_t vals[0]; /**< inlined array of the values/distances in this working set */
-};
+static int loc_compare(const void *a, const void *b)
+{
+ const loc_t *p = a;
+ const loc_t *q = b;
+ return p->time - q->time;
+}
void workset_print(const workset_t *w)
{
int i;
for(i = 0; i < w->len; ++i) {
- ir_printf("%+F %d\n", w->vals[i].irn, w->vals[i].time);
+ ir_fprintf(stderr, "%+F %d\n", w->vals[i].irn, w->vals[i].time);
}
}
/**
* Do NOT alloc anything. Make @param tgt equal to @param src.
- * returns @param tgt for convinience
+ * returns @param tgt for convenience
*/
static INLINE workset_t *workset_copy(belady_env_t *env, workset_t *tgt, workset_t *src) {
size_t size = sizeof(*src) + (env->n_regs)*sizeof(src->vals[0]);
++i)
#define workset_set_time(ws, i, t) (ws)->vals[i].time=t
+#define workset_get_time(ws, i) (ws)->vals[i].time
#define workset_set_length(ws, length) (ws)->len = length
#define workset_get_length(ws) ((ws)->len)
#define workset_get_val(ws, i) ((ws)->vals[i].irn)
static INLINE unsigned get_distance(belady_env_t *env, const ir_node *from, unsigned from_step, const ir_node *def, int skip_from_uses)
{
int flags = arch_irn_get_flags(env->arch, def);
- unsigned dist = be_get_next_use(env->uses, from, from_step, def, skip_from_uses);
+ unsigned dist;
assert(! (flags & arch_irn_flags_ignore));
- // we have to keep nonspillable nodes in the workingset
+
+ /* We have to keep nonspillable nodes in the workingset */
if(flags & arch_irn_flags_dont_spill)
return 0;
+ dist = be_get_next_use(env->uses, from, from_step, def, skip_from_uses);
+
+ if(USES_IS_INFINITE(dist))
+ dist = USES_INFINITY;
+
return dist;
}
+/**
+ * Fix to remove dead nodes (especially don't spill nodes) from workset.
+ */
+static void fix_dead_values(workset_t *ws, ir_node *irn) {
+ int idx;
+ ir_node *node;
+ ir_node *block = get_nodes_block(irn);
+
+ DBG((dbg, DBG_DECIDE, "fixing dead values at %+F:\n", irn));
+
+ workset_foreach(ws, node, idx) {
+ const ir_edge_t *edge;
+ int fixme = 1;
+
+ /* skip already fixed nodes */
+ if (workset_get_time(ws, idx) == INT_MAX)
+ continue;
+
+ /* check all users */
+ foreach_out_edge(node, edge) {
+ ir_node *user = get_edge_src_irn(edge);
+
+ if ((get_nodes_block(user) != block) || /* user is in a different block */
+ (sched_is_scheduled(user) && sched_comes_after(irn, user)) || /* user is scheduled after irn */
+ user == irn) /* irn is the user */
+ { /* => don't fix distance */
+ fixme = 0;
+ break;
+ }
+ }
+
+ /* all users scheduled prior to current irn in in same block as irn -> fix */
+ if (fixme) {
+ workset_set_time(ws, idx, INT_MAX);
+ DBG((dbg, DBG_DECIDE, "\tfixing time for %+F to INT_MAX\n", node));
+ }
+ }
+
+}
+
/**
* Performs the actions necessary to grant the request that:
* - new_vals can be held in registers
*/
static void displace(belady_env_t *env, workset_t *new_vals, int is_usage) {
ir_node *val;
- int i, len, max_allowed, demand, iter;
- workset_t *ws = env->ws;
- ir_node **to_insert = alloca(env->n_regs * sizeof(*to_insert));
+ int i, len, max_allowed, demand, iter;
+
+ workset_t *ws = env->ws;
+ ir_node **to_insert = alloca(env->n_regs * sizeof(*to_insert));
/*
- * 1. Identify the number of needed slots and the values to reload
- */
+ 1. Identify the number of needed slots and the values to reload
+ */
demand = 0;
workset_foreach(new_vals, val, iter) {
/* mark value as used */
if (is_usage)
pset_insert_ptr(env->used, val);
- if (!workset_contains(ws, val)) {
+ if (! workset_contains(ws, val)) {
DBG((dbg, DBG_DECIDE, " insert %+F\n", val));
to_insert[demand++] = val;
- if (is_usage)
+ if (is_usage) {
+ DBG((dbg, DBG_SPILL, "Reload %+F before %+F\n", val, env->instr));
be_add_reload(env->senv, val, env->instr);
- } else {
+ }
+ }
+ else {
assert(is_usage || "Defined value already in workset?!?");
DBG((dbg, DBG_DECIDE, " skip %+F\n", val));
}
DBG((dbg, DBG_DECIDE, " demand = %d\n", demand));
/*
- * 2. Make room for at least 'demand' slots
- */
- len = workset_get_length(ws);
+ 2. Make room for at least 'demand' slots
+ */
+ len = workset_get_length(ws);
max_allowed = env->n_regs - demand;
DBG((dbg, DBG_DECIDE, " disposing %d values\n", ws->len - max_allowed));
/* Only make more free room if we do not have enough */
if (len > max_allowed) {
/* get current next-use distance */
- for (i=0; i<ws->len; ++i)
- workset_set_time(ws, i, get_distance(env, env->instr, env->instr_nr, workset_get_val(ws, i), !is_usage));
+ for (i = 0; i < ws->len; ++i) {
+ unsigned dist = get_distance(env, env->instr, env->instr_nr, workset_get_val(ws, i), !is_usage);
+ workset_set_time(ws, i, dist);
+ }
+
+ /*
+ FIX for don't spill nodes:
+ Problem is that get_distance always returns 0 for those nodes even if they are not
+ needed anymore (all their usages have already been visited).
+ Even if we change this behavior, get_distance doesn't distinguish between not
+ used anymore (dead) and live out of block.
+ Solution: Set distances of all nodes having all their usages in schedule prior to
+ current instruction to MAX_INT.
+ */
+ fix_dead_values(ws, env->instr);
/* sort entries by increasing nextuse-distance*/
workset_sort(ws);
- /* Logic for not needed live-ins: If a value is disposed
- * before its first usage, remove it from start workset
- * We don't do this for phis though
- */
- for (i=max_allowed; i<ws->len; ++i) {
+ /*
+ Logic for not needed live-ins: If a value is disposed
+ before its first usage, remove it from start workset
+ We don't do this for phis though
+ */
+ for (i = max_allowed; i < ws->len; ++i) {
ir_node *irn = ws->vals[i].irn;
- if(is_Phi(irn))
- continue;
+ if (is_Phi(irn))
+ continue;
- if (!pset_find_ptr(env->used, irn)) {
- ir_node *curr_bb = get_nodes_block(env->instr);
+ if (! pset_find_ptr(env->used, irn)) {
+ ir_node *curr_bb = get_nodes_block(env->instr);
workset_t *ws_start = get_block_info(curr_bb)->ws_start;
workset_remove(ws_start, irn);
DBG((dbg, DBG_DECIDE, " dispose %+F dumb\n", irn));
- } else {
+ }
+ else {
DBG((dbg, DBG_DECIDE, " dispose %+F\n", irn));
}
}
}
/*
- * 3. Insert the new values into the workset
- */
- for(i = 0; i < demand; ++i)
+ 3. Insert the new values into the workset
+ */
+ for (i = 0; i < demand; ++i)
workset_insert(env, env->ws, to_insert[i]);
}
static void belady(ir_node *blk, void *env);
/*
- * Computes set of live-ins for each block with multiple predecessors and
- * places copies in the predecessors when phis get spilled
+ * Computes set of live-ins for each block with multiple predecessors
+ * and notifies spill algorithm which phis need to be spilled
*/
-static void place_copy_walker(ir_node *block, void *data) {
+static void spill_phi_walker(ir_node *block, void *data) {
belady_env_t *env = data;
block_info_t *block_info;
- irn_live_t *li;
ir_node *first, *irn;
loc_t loc, *starters;
int i, len, ws_count;
/* Collect all values living at start of block */
starters = NEW_ARR_F(loc_t, 0);
+ /* rebuild schedule time information, because it seems to be broken */
+ sched_renumber(block);
+
DBG((dbg, DBG_START, "Living at start of %+F:\n", block));
first = sched_first(block);
sched_foreach(block, irn) {
DBG((dbg, DBG_START, " %+F:\n", irn));
}
- live_foreach(block, li) {
- if (!live_is_in(li) || !arch_irn_consider_in_reg_alloc(env->arch, env->cls, li->irn))
+ be_lv_foreach(env->cenv->lv, block, be_lv_state_in, i) {
+ ir_node *irn = be_lv_get_irn(env->cenv->lv, block, i);
+ if (!arch_irn_consider_in_reg_alloc(env->arch, env->cls, irn))
continue;
- loc.irn = (ir_node *)li->irn;
- loc.time = get_distance(env, first, 0, li->irn, 0);
+ loc.irn = irn;
+ loc.time = get_distance(env, first, 0, irn, 0);
ARR_APP1(loc_t, starters, loc);
- DBG((dbg, DBG_START, " %+F:\n", li->irn));
+ DBG((dbg, DBG_START, " %+F:\n", irn));
}
// Sort start values by first use
/* irnb is not in memory at the end of pred, so we have to reload it */
DBG((dbg, DBG_FIX, " reload %+F\n", irnb));
+ DBG((dbg, DBG_SPILL, "Reload %+F before %+F,%d\n", irnb, blk, i));
be_add_reload_on_edge(env->senv, irnb, blk, i);
next_value:
belady_env_t env;
FIRM_DBG_REGISTER(dbg, "firm.be.spill.belady");
+ //firm_dbg_set_mask(dbg, DBG_SPILL);
/* init belady env */
obstack_init(&env.ob);
+ env.cenv = chordal_env;
env.arch = chordal_env->birg->main_env->arch_env;
env.cls = chordal_env->cls;
- env.n_regs = arch_count_non_ignore_regs(env.arch, env.cls);
+ env.n_regs = env.cls->n_regs - be_put_ignore_regs(chordal_env->birg, chordal_env->cls, NULL);
env.ws = new_workset(&env, &env.ob);
- env.uses = be_begin_uses(chordal_env->irg, chordal_env->birg->main_env->arch_env, env.cls);
+ env.uses = be_begin_uses(chordal_env->irg, chordal_env->exec_freq, chordal_env->lv);
if(spill_env == NULL) {
env.senv = be_new_spill_env(chordal_env);
} else {
}
DEBUG_ONLY(be_set_spill_env_dbg_module(env.senv, dbg);)
- DBG((dbg, LEVEL_1, "running on register class: %s\n", env.cls->name));
-
- /* do the work */
be_clear_links(chordal_env->irg);
- irg_block_walk_graph(chordal_env->irg, place_copy_walker, NULL, &env);
+ /* Decide which phi nodes will be spilled and place copies for them into the graph */
+ irg_block_walk_graph(chordal_env->irg, spill_phi_walker, NULL, &env);
+ /* Fix high register pressure with belady algorithm */
irg_block_walk_graph(chordal_env->irg, NULL, belady, &env);
+ /* belady was block-local, fix the global flow by adding reloads on the edges */
irg_block_walk_graph(chordal_env->irg, fix_block_borders, NULL, &env);
+ /* Insert spill/reload nodes into the graph and fix usages */
be_insert_spills_reloads(env.senv);
- be_remove_dead_nodes_from_schedule(chordal_env->irg);
-
/* clean up */
if(spill_env == NULL)
be_delete_spill_env(env.senv);
projects / libfirm / blobdiff