ppcg.c

   1 /*
   2  * Copyright 2011      INRIA Saclay
   3  *
   4  * Use of this software is governed by the GNU LGPLv2.1 license
   5  *
   6  * Written by Sven Verdoolaege, INRIA Saclay - Ile-de-France,
   7  * Parc Club Orsay Universite, ZAC des vignes, 4 rue Jacques Monod,
   8  * 91893 Orsay, France
   9  */
  10
  11 #include <assert.h>
  12 #include <stdio.h>
  13 #include <isl/ctx.h>
  14 #include <isl/flow.h>
  15 #include <isl/options.h>
  16 #include <isl/schedule.h>
  17 #include <pet.h>
  18 #include "ppcg.h"
  19 #include "ppcg_options.h"
  20 #include "cuda.h"
  21 #include "cpu.h"
  22
  23 struct options {
  24         struct isl_options *isl;
  25         struct pet_options *pet;
  26         struct ppcg_options *ppcg;
  27         char *input;
  28         char *output;
  29 };
  30
  31 const char *ppcg_version(void);
  32 static void print_version(void)
  33 {
  34         printf("%s", ppcg_version());
  35 }
  36
  37 ISL_ARGS_START(struct options, options_args)
  38 ISL_ARG_CHILD(struct options, isl, "isl", &isl_options_args, "isl options")
  39 ISL_ARG_CHILD(struct options, pet, "pet", &pet_options_args, "pet options")
  40 ISL_ARG_CHILD(struct options, ppcg, NULL, &ppcg_options_args, "ppcg options")
  41 ISL_ARG_STR(struct options, output, 'o', NULL,
  42         "filename", NULL, "output filename (c target)")
  43 ISL_ARG_ARG(struct options, input, "input", NULL)
  44 ISL_ARG_VERSION(print_version)
  45 ISL_ARGS_END
  46
  47 ISL_ARG_DEF(options, struct options, options_args)
  48
  49 /* Is "stmt" a kill statement?
  50  */
  51 static int is_kill(struct pet_stmt *stmt)
  52 {
  53         if (stmt->body->type != pet_expr_unary)
  54                 return 0;
  55         return stmt->body->op == pet_op_kill;
  56 }
  57
  58 /* Is "stmt" not a kill statement?
  59  */
  60 static int is_not_kill(struct pet_stmt *stmt)
  61 {
  62         return !is_kill(stmt);
  63 }
  64
  65 /* Collect the iteration domains of the statements in "scop" that
  66  * satisfy "pred".
  67  */
  68 static __isl_give isl_union_set *collect_domains(struct pet_scop *scop,
  69         int (*pred)(struct pet_stmt *stmt))
  70 {
  71         int i;
  72         isl_set *domain_i;
  73         isl_union_set *domain;
  74
  75         if (!scop)
  76                 return NULL;
  77
  78         domain = isl_union_set_empty(isl_set_get_space(scop->context));
  79
  80         for (i = 0; i < scop->n_stmt; ++i) {
  81                 struct pet_stmt *stmt = scop->stmts[i];
  82
  83                 if (!pred(stmt))
  84                         continue;
  85                 domain_i = isl_set_copy(scop->stmts[i]->domain);
  86                 domain = isl_union_set_add_set(domain, domain_i);
  87         }
  88
  89         return domain;
  90 }
  91
  92 /* Collect the iteration domains of the statements in "scop",
  93  * skipping kill statements.
  94  */
  95 static __isl_give isl_union_set *collect_non_kill_domains(struct pet_scop *scop)
  96 {
  97         return collect_domains(scop, &is_not_kill);
  98 }
  99
 100 /* Does "expr" contain any call expressions?
 101  */
 102 static int expr_has_call(struct pet_expr *expr)
 103 {
 104         int i;
 105
 106         if (expr->type == pet_expr_call)
 107                 return 1;
 108
 109         for (i = 0; i < expr->n_arg; ++i)
 110                 if (expr_has_call(expr->args[i]))
 111                         return 1;
 112
 113         return 0;
 114 }
 115
 116 /* Does "stmt" contain any call expressions?
 117  */
 118 static int has_call(struct pet_stmt *stmt)
 119 {
 120         return expr_has_call(stmt->body);
 121 }
 122
 123 /* Collect the iteration domains of the statements in "scop"
 124  * that contain a call expression.
 125  */
 126 static __isl_give isl_union_set *collect_call_domains(struct pet_scop *scop)
 127 {
 128         return collect_domains(scop, &has_call);
 129 }
 130
 131 /* Collect all kill accesses in "scop".
 132  */
 133 static __isl_give isl_union_map *collect_kills(struct pet_scop *scop)
 134 {
 135         int i;
 136         isl_union_map *kills;
 137
 138         if (!scop)
 139                 return NULL;
 140
 141         kills = isl_union_map_empty(isl_set_get_space(scop->context));
 142
 143         for (i = 0; i < scop->n_stmt; ++i) {
 144                 struct pet_stmt *stmt = scop->stmts[i];
 145                 isl_map *kill_i;
 146
 147                 if (!is_kill(stmt))
 148                         continue;
 149                 kill_i = isl_map_copy(stmt->body->args[0]->acc.access);
 150                 kill_i = isl_map_intersect_domain(kill_i,
 151                                                     isl_set_copy(stmt->domain));
 152                 kills = isl_union_map_add_map(kills, kill_i);
 153         }
 154
 155         return kills;
 156 }
 157
 158 /* Compute the dependences of the program represented by "scop".
 159  * Store the computed flow dependences
 160  * in scop->dep_flow and the reads with no corresponding writes in
 161  * scop->live_in.
 162  * Store the false (anti and output) dependences in scop->dep_false.
 163  */
 164 static void compute_dependences(struct ppcg_scop *scop)
 165 {
 166         isl_union_map *empty;
 167         isl_union_map *dep1, *dep2;
 168
 169         if (!scop)
 170                 return;
 171
 172         empty = isl_union_map_empty(isl_union_set_get_space(scop->domain));
 173         isl_union_map_compute_flow(isl_union_map_copy(scop->reads),
 174                                 isl_union_map_copy(scop->writes), empty,
 175                                 isl_union_map_copy(scop->schedule),
 176                                 &scop->dep_flow, NULL, &scop->live_in, NULL);
 177
 178         isl_union_map_compute_flow(isl_union_map_copy(scop->writes),
 179                                 isl_union_map_copy(scop->writes),
 180                                 isl_union_map_copy(scop->reads),
 181                                 isl_union_map_copy(scop->schedule),
 182                                 &dep1, &dep2, NULL, NULL);
 183
 184         scop->dep_false = isl_union_map_union(dep1, dep2);
 185         scop->dep_false = isl_union_map_coalesce(scop->dep_false);
 186 }
 187
 188 /* Eliminate dead code from ps->domain.
 189  *
 190  * In particular, intersect ps->domain with the (parts of) iteration
 191  * domains that are needed to produce the output or for statement
 192  * iterations that call functions.
 193  *
 194  * We start with the iteration domains that call functions
 195  * and the set of iterations that last write to an array
 196  * (except those that are later killed).
 197  *
 198  * Then we add those statement iterations that produce
 199  * something needed by the "live" statements iterations.
 200  * We keep doing this until no more statement iterations can be added.
 201  * To ensure that the procedure terminates, we compute the affine
 202  * hull of the live iterations (bounded to the original iteration
 203  * domains) each time we have added extra iterations.
 204  */
 205 static void eliminate_dead_code(struct ppcg_scop *ps)
 206 {
 207         isl_union_map *exposed;
 208         isl_union_set *live;
 209         isl_union_map *dep;
 210
 211         exposed = isl_union_map_union(isl_union_map_copy(ps->writes),
 212                                             isl_union_map_copy(ps->kills));
 213         exposed = isl_union_map_reverse(exposed);
 214         exposed = isl_union_map_apply_range(exposed,
 215                                             isl_union_map_copy(ps->schedule));
 216         exposed = isl_union_map_lexmax(exposed);
 217         exposed = isl_union_map_apply_range(exposed,
 218                     isl_union_map_reverse(isl_union_map_copy(ps->schedule)));
 219
 220         live = isl_union_map_range(exposed);
 221         live = isl_union_set_union(live, isl_union_set_copy(ps->call));
 222
 223         dep = isl_union_map_copy(ps->dep_flow);
 224         dep = isl_union_map_reverse(dep);
 225
 226         for (;;) {
 227                 isl_union_set *extra;
 228
 229                 extra = isl_union_set_apply(isl_union_set_copy(live),
 230                                             isl_union_map_copy(dep));
 231                 if (isl_union_set_is_subset(extra, live)) {
 232                         isl_union_set_free(extra);
 233                         break;
 234                 }
 235
 236                 live = isl_union_set_union(live, extra);
 237                 live = isl_union_set_affine_hull(live);
 238                 live = isl_union_set_intersect(live,
 239                                             isl_union_set_copy(ps->domain));
 240         }
 241
 242         isl_union_map_free(dep);
 243
 244         ps->domain = isl_union_set_intersect(ps->domain, live);
 245 }
 246
 247 /* Extract a ppcg_scop from a pet_scop.
 248  *
 249  * The constructed ppcg_scop refers to elements from the pet_scop
 250  * so the pet_scop should not be freed before the ppcg_scop.
 251  */
 252 static struct ppcg_scop *ppcg_scop_from_pet_scop(struct pet_scop *scop)
 253 {
 254         isl_ctx *ctx;
 255         struct ppcg_scop *ps;
 256
 257         if (!scop)
 258                 return NULL;
 259
 260         ctx = isl_set_get_ctx(scop->context);
 261
 262         ps = isl_calloc_type(ctx, struct ppcg_scop);
 263         if (!ps)
 264                 return NULL;
 265
 266         ps->context = isl_set_copy(scop->context);
 267         ps->domain = collect_non_kill_domains(scop);
 268         ps->call = collect_call_domains(scop);
 269         ps->reads = pet_scop_collect_reads(scop);
 270         ps->writes = pet_scop_collect_writes(scop);
 271         ps->kills = collect_kills(scop);
 272         ps->schedule = pet_scop_collect_schedule(scop);
 273         ps->n_array = scop->n_array;
 274         ps->arrays = scop->arrays;
 275         ps->n_stmt = scop->n_stmt;
 276         ps->stmts = scop->stmts;
 277
 278         compute_dependences(ps);
 279         eliminate_dead_code(ps);
 280
 281         return ps;
 282 }
 283
 284 static void ppcg_scop_free(struct ppcg_scop *ps)
 285 {
 286         if (!ps)
 287                 return;
 288
 289         isl_set_free(ps->context);
 290         isl_union_set_free(ps->domain);
 291         isl_union_set_free(ps->call);
 292         isl_union_map_free(ps->reads);
 293         isl_union_map_free(ps->live_in);
 294         isl_union_map_free(ps->writes);
 295         isl_union_map_free(ps->kills);
 296         isl_union_map_free(ps->dep_flow);
 297         isl_union_map_free(ps->dep_false);
 298         isl_union_map_free(ps->schedule);
 299
 300         free(ps);
 301 }
 302
 303 int main(int argc, char **argv)
 304 {
 305         int r;
 306         isl_ctx *ctx;
 307         struct options *options;
 308         struct pet_scop *scop;
 309         struct ppcg_scop *ps;
 310
 311         options = options_new_with_defaults();
 312         assert(options);
 313
 314         ctx = isl_ctx_alloc_with_options(&options_args, options);
 315         isl_options_set_schedule_outer_zero_distance(ctx, 1);
 316         argc = options_parse(options, argc, argv, ISL_ARG_ALL);
 317
 318         scop = pet_scop_extract_from_C_source(ctx, options->input, NULL);
 319         scop = pet_scop_align_params(scop);
 320         ps = ppcg_scop_from_pet_scop(scop);
 321
 322         if (options->ppcg->target == PPCG_TARGET_CUDA)
 323                 r = generate_cuda(ctx, ps, options->ppcg, options->input);
 324         else
 325                 r = generate_cpu(ctx, ps, options->ppcg, options->input,
 326                                 options->output);
 327
 328         ppcg_scop_free(ps);
 329         pet_scop_free(scop);
 330
 331         isl_ctx_free(ctx);
 332
 333         return r;
 334 }