gcc/multiple_target.c

   1 /* Pass for parsing functions with multiple target attributes.
   2
   3    Contributed by Evgeny Stupachenko <evstupac@gmail.com>
   4
   5    Copyright (C) 2015-2017 Free Software Foundation, Inc.
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 3, or (at your option) any later
  12 version.
  13
  14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17 for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "backend.h"
  27 #include "tree.h"
  28 #include "stringpool.h"
  29 #include "gimple.h"
  30 #include "diagnostic-core.h"
  31 #include "gimple-ssa.h"
  32 #include "cgraph.h"
  33 #include "tree-pass.h"
  34 #include "target.h"
  35 #include "attribs.h"
  36 #include "pretty-print.h"
  37
  38 /* If the call in NODE has multiple target attribute with multiple fields,
  39    replace it with dispatcher call and create dispatcher (once).  */
  40
  41 static void
  42 create_dispatcher_calls (struct cgraph_node *node)
  43 {
  44   cgraph_edge *e;
  45   cgraph_edge *e_next = NULL;
  46
  47   /* We need to remember NEXT_CALLER as it could be modified in the loop.  */
  48   for (e = node->callers; e ;e = (e == NULL) ? e_next : e->next_caller)
  49     {
  50       tree resolver_decl;
  51       tree idecl;
  52       tree decl;
  53       gimple *call = e->call_stmt;
  54       struct cgraph_node *inode;
  55
  56       /* Checking if call of function is call of versioned function.
  57          Versioned function are not inlined, so there is no need to
  58          check for inline.  */
  59       if (!call
  60           || !(decl = gimple_call_fndecl (call))
  61           || !DECL_FUNCTION_VERSIONED (decl))
  62         continue;
  63
  64       if (!targetm.has_ifunc_p ())
  65         {
  66           error_at (gimple_location (call),
  67                     "the call requires ifunc, which is not"
  68                     " supported by this target");
  69           break;
  70         }
  71       e_next = e->next_caller;
  72       idecl = targetm.get_function_versions_dispatcher (decl);
  73       if (!idecl)
  74         {
  75           error_at (gimple_location (call),
  76                     "default target_clones attribute was not set");
  77           break;
  78         }
  79       inode = cgraph_node::get (idecl);
  80       gcc_assert (inode);
  81       resolver_decl = targetm.generate_version_dispatcher_body (inode);
  82
  83       /* Update aliases.  */
  84       inode->alias = true;
  85       inode->alias_target = resolver_decl;
  86       if (!inode->analyzed)
  87         inode->resolve_alias (cgraph_node::get (resolver_decl));
  88
  89       e->redirect_callee (inode);
  90       /*  Since REDIRECT_CALLEE modifies NEXT_CALLER field we move to
  91           previously set NEXT_CALLER.  */
  92       e = NULL;
  93     }
  94 }
  95
  96 /* Return length of attribute names string,
  97    if arglist chain > 1, -1 otherwise.  */
  98
  99 static int
 100 get_attr_len (tree arglist)
 101 {
 102   tree arg;
 103   int str_len_sum = 0;
 104   int argnum = 0;
 105
 106   for (arg = arglist; arg; arg = TREE_CHAIN (arg))
 107     {
 108       const char *str = TREE_STRING_POINTER (TREE_VALUE (arg));
 109       size_t len = strlen (str);
 110       str_len_sum += len + 1;
 111       for (const char *p = strchr (str, ','); p; p = strchr (p + 1, ','))
 112         argnum++;
 113       argnum++;
 114     }
 115   if (argnum <= 1)
 116     return -1;
 117   return str_len_sum;
 118 }
 119
 120 /* Create string with attributes separated by comma.
 121    Return number of attributes.  */
 122
 123 static int
 124 get_attr_str (tree arglist, char *attr_str)
 125 {
 126   tree arg;
 127   size_t str_len_sum = 0;
 128   int argnum = 0;
 129
 130   for (arg = arglist; arg; arg = TREE_CHAIN (arg))
 131     {
 132       const char *str = TREE_STRING_POINTER (TREE_VALUE (arg));
 133       size_t len = strlen (str);
 134       for (const char *p = strchr (str, ','); p; p = strchr (p + 1, ','))
 135         argnum++;
 136       memcpy (attr_str + str_len_sum, str, len);
 137       attr_str[str_len_sum + len] = TREE_CHAIN (arg) ? ',' : '\0';
 138       str_len_sum += len + 1;
 139       argnum++;
 140     }
 141   return argnum;
 142 }
 143
 144 /* Return number of attributes separated by comma and put them into ARGS.
 145    If there is no DEFAULT attribute return -1.  */
 146
 147 static int
 148 separate_attrs (char *attr_str, char **attrs)
 149 {
 150   int i = 0;
 151   bool has_default = false;
 152
 153   for (char *attr = strtok (attr_str, ",");
 154        attr != NULL; attr = strtok (NULL, ","))
 155     {
 156       if (strcmp (attr, "default") == 0)
 157         {
 158           has_default = true;
 159           continue;
 160         }
 161       attrs[i++] = attr;
 162     }
 163   if (!has_default)
 164     return -1;
 165   return i;
 166 }
 167
 168 /*  Return true if symbol is valid in assembler name.  */
 169
 170 static bool
 171 is_valid_asm_symbol (char c)
 172 {
 173   if ('a' <= c && c <= 'z')
 174     return true;
 175   if ('A' <= c && c <= 'Z')
 176     return true;
 177   if ('0' <= c && c <= '9')
 178     return true;
 179   if (c == '_')
 180     return true;
 181   return false;
 182 }
 183
 184 /*  Replace all not valid assembler symbols with '_'.  */
 185
 186 static void
 187 create_new_asm_name (char *old_asm_name, char *new_asm_name)
 188 {
 189   int i;
 190   int old_name_len = strlen (old_asm_name);
 191
 192   /* Replace all not valid assembler symbols with '_'.  */
 193   for (i = 0; i < old_name_len; i++)
 194     if (!is_valid_asm_symbol (old_asm_name[i]))
 195       new_asm_name[i] = '_';
 196     else
 197       new_asm_name[i] = old_asm_name[i];
 198   new_asm_name[old_name_len] = '\0';
 199 }
 200
 201 /*  Creates target clone of NODE.  */
 202
 203 static cgraph_node *
 204 create_target_clone (cgraph_node *node, bool definition, char *name)
 205 {
 206   cgraph_node *new_node;
 207
 208   if (definition)
 209     {
 210       new_node = node->create_version_clone_with_body (vNULL, NULL,
 211                                                        NULL, false,
 212                                                        NULL, NULL,
 213                                                        name);
 214       new_node->force_output = true;
 215     }
 216   else
 217     {
 218       tree new_decl = copy_node (node->decl);
 219       new_node = cgraph_node::get_create (new_decl);
 220       /* Generate a new name for the new version.  */
 221       symtab->change_decl_assembler_name (new_node->decl,
 222                                           clone_function_name (node->decl,
 223                                                                name));
 224     }
 225   return new_node;
 226 }
 227
 228 /* If the function in NODE has multiple target attributes
 229    create the appropriate clone for each valid target attribute.  */
 230
 231 static bool
 232 expand_target_clones (struct cgraph_node *node, bool definition)
 233 {
 234   int i;
 235   /* Parsing target attributes separated by comma.  */
 236   tree attr_target = lookup_attribute ("target_clones",
 237                                        DECL_ATTRIBUTES (node->decl));
 238   /* No targets specified.  */
 239   if (!attr_target)
 240     return false;
 241
 242   tree arglist = TREE_VALUE (attr_target);
 243   int attr_len = get_attr_len (arglist);
 244
 245   /* No need to clone for 1 target attribute.  */
 246   if (attr_len == -1)
 247     {
 248       warning_at (DECL_SOURCE_LOCATION (node->decl),
 249                   0,
 250                   "single target_clones attribute is ignored");
 251       return false;
 252     }
 253
 254   char *attr_str = XNEWVEC (char, attr_len);
 255   int attrnum = get_attr_str (arglist, attr_str);
 256   char **attrs = XNEWVEC (char *, attrnum);
 257
 258   attrnum = separate_attrs (attr_str, attrs);
 259   if (attrnum == -1)
 260     {
 261       error_at (DECL_SOURCE_LOCATION (node->decl),
 262                 "default target was not set");
 263       XDELETEVEC (attrs);
 264       XDELETEVEC (attr_str);
 265       return false;
 266     }
 267
 268   cgraph_function_version_info *decl1_v = NULL;
 269   cgraph_function_version_info *decl2_v = NULL;
 270   cgraph_function_version_info *before = NULL;
 271   cgraph_function_version_info *after = NULL;
 272   decl1_v = node->function_version ();
 273   if (decl1_v == NULL)
 274     decl1_v = node->insert_new_function_version ();
 275   before = decl1_v;
 276   DECL_FUNCTION_VERSIONED (node->decl) = 1;
 277
 278   for (i = 0; i < attrnum; i++)
 279     {
 280       char *attr = attrs[i];
 281       char *suffix = XNEWVEC (char, strlen (attr) + 1);
 282
 283       create_new_asm_name (attr, suffix);
 284       /* Create new target clone.  */
 285       cgraph_node *new_node = create_target_clone (node, definition, suffix);
 286       XDELETEVEC (suffix);
 287
 288       /* Set new attribute for the clone.  */
 289       tree attributes = make_attribute ("target", attr,
 290                                         DECL_ATTRIBUTES (new_node->decl));
 291       DECL_ATTRIBUTES (new_node->decl) = attributes;
 292       location_t saved_loc = input_location;
 293       input_location = DECL_SOURCE_LOCATION (node->decl);
 294       if (!targetm.target_option.valid_attribute_p (new_node->decl, NULL,
 295                                                     TREE_VALUE (attributes),
 296                                                     0))
 297         {
 298           input_location = saved_loc;
 299           continue;
 300         }
 301
 302       input_location = saved_loc;
 303       decl2_v = new_node->function_version ();
 304       if (decl2_v != NULL)
 305         continue;
 306       decl2_v = new_node->insert_new_function_version ();
 307
 308       /* Chain decl2_v and decl1_v.  All semantically identical versions
 309          will be chained together.  */
 310       after = decl2_v;
 311       while (before->next != NULL)
 312         before = before->next;
 313       while (after->prev != NULL)
 314         after = after->prev;
 315
 316       before->next = after;
 317       after->prev = before;
 318       DECL_FUNCTION_VERSIONED (new_node->decl) = 1;
 319     }
 320
 321   XDELETEVEC (attrs);
 322   XDELETEVEC (attr_str);
 323
 324   /* Setting new attribute to initial function.  */
 325   tree attributes = make_attribute ("target", "default",
 326                                     DECL_ATTRIBUTES (node->decl));
 327   DECL_ATTRIBUTES (node->decl) = attributes;
 328   location_t saved_loc = input_location;
 329   input_location = DECL_SOURCE_LOCATION (node->decl);
 330   bool ret
 331     = targetm.target_option.valid_attribute_p (node->decl, NULL,
 332                                                TREE_VALUE (attributes), 0);
 333   input_location = saved_loc;
 334   return ret;
 335 }
 336
 337 static bool target_clone_pass;
 338
 339 static unsigned int
 340 ipa_target_clone (void)
 341 {
 342   struct cgraph_node *node;
 343
 344   target_clone_pass = false;
 345   FOR_EACH_FUNCTION (node)
 346     if (node->definition)
 347       target_clone_pass |= expand_target_clones (node, true);
 348   return 0;
 349 }
 350
 351 namespace {
 352
 353 const pass_data pass_data_target_clone =
 354 {
 355   SIMPLE_IPA_PASS,              /* type */
 356   "targetclone",                /* name */
 357   OPTGROUP_NONE,                /* optinfo_flags */
 358   TV_NONE,                      /* tv_id */
 359   ( PROP_ssa | PROP_cfg ),      /* properties_required */
 360   0,                            /* properties_provided */
 361   0,                            /* properties_destroyed */
 362   0,                            /* todo_flags_start */
 363   0                             /* todo_flags_finish */
 364 };
 365
 366 class pass_target_clone : public simple_ipa_opt_pass
 367 {
 368 public:
 369   pass_target_clone (gcc::context *ctxt)
 370     : simple_ipa_opt_pass (pass_data_target_clone, ctxt)
 371   {}
 372
 373   /* opt_pass methods: */
 374   virtual bool gate (function *);
 375   virtual unsigned int execute (function *) { return ipa_target_clone (); }
 376 };
 377
 378 bool
 379 pass_target_clone::gate (function *)
 380 {
 381   return true;
 382 }
 383
 384 } // anon namespace
 385
 386 simple_ipa_opt_pass *
 387 make_pass_target_clone (gcc::context *ctxt)
 388 {
 389   return new pass_target_clone (ctxt);
 390 }
 391
 392 static unsigned int
 393 ipa_dispatcher_calls (void)
 394 {
 395   struct cgraph_node *node;
 396
 397   FOR_EACH_FUNCTION (node)
 398     if (!node->definition)
 399       target_clone_pass |= expand_target_clones (node, false);
 400   if (target_clone_pass)
 401     FOR_EACH_FUNCTION (node)
 402       create_dispatcher_calls (node);
 403   return 0;
 404 }
 405
 406 namespace {
 407
 408 const pass_data pass_data_dispatcher_calls =
 409 {
 410   SIMPLE_IPA_PASS,              /* type */
 411   "dispatchercalls",            /* name */
 412   OPTGROUP_NONE,                /* optinfo_flags */
 413   TV_NONE,                      /* tv_id */
 414   ( PROP_ssa | PROP_cfg ),      /* properties_required */
 415   0,                            /* properties_provided */
 416   0,                            /* properties_destroyed */
 417   0,                            /* todo_flags_start */
 418   0                             /* todo_flags_finish */
 419 };
 420
 421 class pass_dispatcher_calls : public simple_ipa_opt_pass
 422 {
 423 public:
 424   pass_dispatcher_calls (gcc::context *ctxt)
 425     : simple_ipa_opt_pass (pass_data_dispatcher_calls, ctxt)
 426   {}
 427
 428   /* opt_pass methods: */
 429   virtual bool gate (function *);
 430   virtual unsigned int execute (function *) { return ipa_dispatcher_calls (); }
 431 };
 432
 433 bool
 434 pass_dispatcher_calls::gate (function *)
 435 {
 436   return true;
 437 }
 438
 439 } // anon namespace
 440
 441 simple_ipa_opt_pass *
 442 make_pass_dispatcher_calls (gcc::context *ctxt)
 443 {
 444   return new pass_dispatcher_calls (ctxt);
 445 }