4 * Copyright: (c) Universitaet Karlsruhe
5 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
25 #include <libcore/lc_opts.h>
26 #include <libcore/lc_opts_enum.h>
34 #include "irprintf_t.h"
36 #include "irgraph_t.h"
38 #include "iredges_t.h"
42 #include "beraextern.h"
47 #include "besched_t.h"
52 #include "bessadestrsimple.h"
56 typedef struct _ssa_destr_env_t {
58 const arch_register_class_t *cls;
59 const arch_env_t *aenv;
63 #define pset_foreach(pset, irn) for(irn=pset_first(pset); irn; irn=pset_next(pset))
64 #define set_foreach(set, e) for(e=set_first(set); e; e=set_next(set))
66 /******************************************************************************
68 \ \ / / | | |__ \ \ \ / /
69 \ \ / /_ _| |___ ) | \ \ / /_ _ _ __ ___
70 \ \/ / _` | / __| / / \ \/ / _` | '__/ __|
71 \ / (_| | \__ \ / /_ \ / (_| | | \__ \
72 \/ \__,_|_|___/ |____| \/ \__,_|_| |___/
73 *****************************************************************************/
76 * The link field of an irn points to the var_info struct
77 * representing the corresponding variable.
79 #define set_var_info(irn, vi) set_irn_link(irn, vi)
81 #define HASH_VAR_NR(var_nr) var_nr
83 static int compare_var_infos(const void *e1, const void *e2, size_t size) {
84 const be_var_info_t *v1 = e1;
85 const be_var_info_t *v2 = e2;
87 if (v1->var_nr == SET_REMOVED || v2->var_nr == SET_REMOVED)
90 return v1->var_nr != v2->var_nr;
93 be_var_info_t *be_var_find(set *vars, int var_nr) {
97 return set_find(vars, &vi, sizeof(vi), HASH_VAR_NR(var_nr));
100 be_var_info_t *be_var_find_or_insert(set *vars, int var_nr) {
101 be_var_info_t vi, *found;
102 memset(&vi, 0, sizeof(vi));
105 found = set_insert(vars, &vi, sizeof(vi), HASH_VAR_NR(var_nr));
108 found->values = pset_new_ptr(1);
114 * Adds a value to a variable. Sets all pointers accordingly.
116 be_var_info_t *be_var_add_value(set *vars, int var_nr, ir_node *irn) {
117 be_var_info_t *vi = be_var_find_or_insert(vars, var_nr);
119 /* var 2 value mapping */
120 pset_insert_ptr(vi->values, irn);
122 /* value 2 var mapping */
123 set_var_info(irn, vi);
128 pset *be_get_var_values(set *vars, int var_nr) {
129 be_var_info_t *vi = be_var_find(vars, var_nr);
130 assert(vi && "Variable does not exist");
134 static INLINE ir_node *get_first_phi(pset *s) {
143 assert(0 && "There must be a phi in this");
149 * Define variables (numbers) for all SSA-values.
150 * All values in a phi class get assigned the same variable name.
151 * The link field maps values to the var-name
153 static void values_to_vars(ir_node *irn, void *env) {
154 ssa_destr_env_t *sde = env;
158 if(arch_get_irn_reg_class(sde->aenv, irn, -1) == NULL)
161 vals = get_phi_class(irn);
164 nr = get_irn_node_nr(get_first_phi(vals));
166 /* not a phi class member, value == var */
167 nr = get_irn_node_nr(irn);
168 vals = pset_new_ptr(1);
169 pset_insert_ptr(vals, irn);
172 /* values <--> var mapping */
173 pset_foreach(vals, irn) {
174 be_var_add_value(sde->vars, nr, irn);
178 /******************************************************************************
180 / ____/ ____| /\ | __ \ | |
181 | (___| (___ / \ ______| | | | ___ ___| |_ _ __
182 \___ \\___ \ / /\ \______| | | |/ _ \/ __| __| '__|
183 ____) |___) / ____ \ | |__| | __/\__ \ |_| |
184 |_____/_____/_/ \_\ |_____/ \___||___/\__|_|
186 *****************************************************************************/
188 #define mark_as_done(irn, pos) set_irn_link(irn, INT_TO_PTR(pos+1))
189 #define has_been_done(irn, pos) (PTR_TO_INT(get_irn_link(irn)) > pos)
192 * Insert a copy for the argument of @p start_phi found at position @p pos.
193 * Also searches a phi-loop of arbitrary length to detect and resolve
194 * the class of phi-swap-problems. To search for a loop recursion is used.
196 * 1) Simplest case (phi with a non-phi arg):
197 * A single copy is inserted.
199 * 2) Phi chain (phi (with phi-arg)* with non=phi arg):
200 * Several copies are placed, each after returning from recursion.
203 * On detection a loop breaker is inserted, which is a copy of the start_phi.
204 * This copy then pretends beeing the argumnent of the last phi.
205 * Now case 2) can be used.
207 * The values of @p start_phi and @p pos never change during recursion.
209 * @p start_phi Phi node to process
210 * @p pos Argument position to insert copy/copies for
211 * @p curr_phi Phi node currently processed during recursion. Equals start_phi on initial call
213 * @return NULL If no copy is necessary
214 * NULL If the phi has already been processed at this pos
215 * Link field is used to keep track of processed positions
216 * In all other cases the ir_node *copy which was placed is returned.
218 static ir_node *insert_copies(ssa_destr_env_t *sde, const arch_register_class_t *cls, ir_node *start_phi, int pos, ir_node *curr_phi) {
219 ir_node *arg = get_irn_n(curr_phi, pos);
220 ir_node *arg_blk = get_nodes_block(arg);
221 ir_node *pred_blk = get_Block_cfgpred_block(get_nodes_block(curr_phi), pos);
222 ir_node *curr_cpy, *last_cpy;
224 assert(is_Phi(start_phi) && is_Phi(curr_phi));
226 if (has_been_done(start_phi, pos))
229 /* In case this is a 'normal' phi we insert at the
230 * end of the pred block before cf nodes */
231 last_cpy = sched_skip(pred_blk, 0, sched_skip_cf_predicator, (void *)sde->aenv);
232 last_cpy = sched_next(last_cpy);
234 /* If we detect a loop stop recursion. */
235 if (arg == start_phi) {
236 ir_node *loop_breaker;
237 if (start_phi == curr_phi) {
238 /* Phi directly uses itself. No copy necessary */
242 /* At least 2 phis are involved */
243 /* Insert a loop breaking copy (an additional variable T) */
244 loop_breaker = be_new_Copy(cls, sde->irg, pred_blk, start_phi);
245 sched_add_before(last_cpy, loop_breaker);
250 /* If arg is a phi in the same block we have to continue search */
251 if (is_Phi(arg) && arg_blk == get_nodes_block(start_phi))
252 last_cpy = insert_copies(sde, cls, start_phi, pos, arg);
254 /* Insert copy of argument (may be the loop-breaker) */
255 curr_cpy = be_new_Copy(cls, sde->irg, pred_blk, arg);
256 set_irn_n(curr_phi, pos, curr_cpy);
257 mark_as_done(curr_phi, pos);
258 sched_add_before(last_cpy, curr_cpy);
264 * Perform simple SSA-destruction with copies.
265 * The order of processing _must_ be
266 * for all positions {
271 * else the magic to keep track of processed phi-positions will fail in
272 * function 'insert_copies'
274 static void ssa_destr_simple_walker(ir_node *blk, void *env) {
275 ssa_destr_env_t *sde = env;
278 const arch_register_class_t *cls;
280 /* for all argument positions of the phis */
281 for (pos=0, max=get_irn_arity(blk); pos<max; ++pos) {
283 /* for all phi nodes (which are scheduled first) */
284 sched_foreach(blk, phi) {
288 if (arch_irn_is(sde->aenv, phi, ignore))
291 cls = arch_get_irn_reg_class(sde->aenv, phi, -1);
292 insert_copies(sde, cls, phi, pos, phi);
298 set *be_ssa_destr_simple(ir_graph *irg, const arch_env_t *aenv) {
303 sde.vars = new_set(compare_var_infos, 16);
306 irg_block_walk_graph(irg, ssa_destr_simple_walker, NULL, &sde);
308 /* Mapping of SSA-Values <--> Variables */
309 phi_class_compute(irg);
311 irg_walk_graph(irg, values_to_vars, NULL, &sde);
316 void free_ssa_destr_simple(set *vars)
320 set_foreach(vars, vi)
321 del_pset(vi->values);