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       e->redirect_call_stmt_to_callee ();
  91       /*  Since REDIRECT_CALLEE modifies NEXT_CALLER field we move to
  92           previously set NEXT_CALLER.  */
  93       e = NULL;
  94     }
  95 }
  96
  97 /* Return length of attribute names string,
  98    if arglist chain > 1, -1 otherwise.  */
  99
 100 static int
 101 get_attr_len (tree arglist)
 102 {
 103   tree arg;
 104   int str_len_sum = 0;
 105   int argnum = 0;
 106
 107   for (arg = arglist; arg; arg = TREE_CHAIN (arg))
 108     {
 109       const char *str = TREE_STRING_POINTER (TREE_VALUE (arg));
 110       size_t len = strlen (str);
 111       str_len_sum += len + 1;
 112       for (const char *p = strchr (str, ','); p; p = strchr (p + 1, ','))
 113         argnum++;
 114       argnum++;
 115     }
 116   if (argnum <= 1)
 117     return -1;
 118   return str_len_sum;
 119 }
 120
 121 /* Create string with attributes separated by comma.
 122    Return number of attributes.  */
 123
 124 static int
 125 get_attr_str (tree arglist, char *attr_str)
 126 {
 127   tree arg;
 128   size_t str_len_sum = 0;
 129   int argnum = 0;
 130
 131   for (arg = arglist; arg; arg = TREE_CHAIN (arg))
 132     {
 133       const char *str = TREE_STRING_POINTER (TREE_VALUE (arg));
 134       size_t len = strlen (str);
 135       for (const char *p = strchr (str, ','); p; p = strchr (p + 1, ','))
 136         argnum++;
 137       memcpy (attr_str + str_len_sum, str, len);
 138       attr_str[str_len_sum + len] = TREE_CHAIN (arg) ? ',' : '\0';
 139       str_len_sum += len + 1;
 140       argnum++;
 141     }
 142   return argnum;
 143 }
 144
 145 /* Return number of attributes separated by comma and put them into ARGS.
 146    If there is no DEFAULT attribute return -1.  */
 147
 148 static int
 149 separate_attrs (char *attr_str, char **attrs)
 150 {
 151   int i = 0;
 152   bool has_default = false;
 153
 154   for (char *attr = strtok (attr_str, ",");
 155        attr != NULL; attr = strtok (NULL, ","))
 156     {
 157       if (strcmp (attr, "default") == 0)
 158         {
 159           has_default = true;
 160           continue;
 161         }
 162       attrs[i++] = attr;
 163     }
 164   if (!has_default)
 165     return -1;
 166   return i;
 167 }
 168
 169 /*  Return true if symbol is valid in assembler name.  */
 170
 171 static bool
 172 is_valid_asm_symbol (char c)
 173 {
 174   if ('a' <= c && c <= 'z')
 175     return true;
 176   if ('A' <= c && c <= 'Z')
 177     return true;
 178   if ('0' <= c && c <= '9')
 179     return true;
 180   if (c == '_')
 181     return true;
 182   return false;
 183 }
 184
 185 /*  Replace all not valid assembler symbols with '_'.  */
 186
 187 static void
 188 create_new_asm_name (char *old_asm_name, char *new_asm_name)
 189 {
 190   int i;
 191   int old_name_len = strlen (old_asm_name);
 192
 193   /* Replace all not valid assembler symbols with '_'.  */
 194   for (i = 0; i < old_name_len; i++)
 195     if (!is_valid_asm_symbol (old_asm_name[i]))
 196       new_asm_name[i] = '_';
 197     else
 198       new_asm_name[i] = old_asm_name[i];
 199   new_asm_name[old_name_len] = '\0';
 200 }
 201
 202 /*  Creates target clone of NODE.  */
 203
 204 static cgraph_node *
 205 create_target_clone (cgraph_node *node, bool definition, char *name)
 206 {
 207   cgraph_node *new_node;
 208
 209   if (definition)
 210     {
 211       new_node = node->create_version_clone_with_body (vNULL, NULL,
 212                                                        NULL, false,
 213                                                        NULL, NULL,
 214                                                        name);
 215       new_node->force_output = true;
 216     }
 217   else
 218     {
 219       tree new_decl = copy_node (node->decl);
 220       new_node = cgraph_node::get_create (new_decl);
 221       /* Generate a new name for the new version.  */
 222       symtab->change_decl_assembler_name (new_node->decl,
 223                                           clone_function_name (node->decl,
 224                                                                name));
 225     }
 226   return new_node;
 227 }
 228
 229 /* If the function in NODE has multiple target attributes
 230    create the appropriate clone for each valid target attribute.  */
 231
 232 static bool
 233 expand_target_clones (struct cgraph_node *node, bool definition)
 234 {
 235   int i;
 236   /* Parsing target attributes separated by comma.  */
 237   tree attr_target = lookup_attribute ("target_clones",
 238                                        DECL_ATTRIBUTES (node->decl));
 239   /* No targets specified.  */
 240   if (!attr_target)
 241     return false;
 242
 243   tree arglist = TREE_VALUE (attr_target);
 244   int attr_len = get_attr_len (arglist);
 245
 246   /* No need to clone for 1 target attribute.  */
 247   if (attr_len == -1)
 248     {
 249       warning_at (DECL_SOURCE_LOCATION (node->decl),
 250                   0,
 251                   "single target_clones attribute is ignored");
 252       return false;
 253     }
 254
 255   char *attr_str = XNEWVEC (char, attr_len);
 256   int attrnum = get_attr_str (arglist, attr_str);
 257   char **attrs = XNEWVEC (char *, attrnum);
 258
 259   attrnum = separate_attrs (attr_str, attrs);
 260   if (attrnum == -1)
 261     {
 262       error_at (DECL_SOURCE_LOCATION (node->decl),
 263                 "default target was not set");
 264       XDELETEVEC (attrs);
 265       XDELETEVEC (attr_str);
 266       return false;
 267     }
 268
 269   cgraph_function_version_info *decl1_v = NULL;
 270   cgraph_function_version_info *decl2_v = NULL;
 271   cgraph_function_version_info *before = NULL;
 272   cgraph_function_version_info *after = NULL;
 273   decl1_v = node->function_version ();
 274   if (decl1_v == NULL)
 275     decl1_v = node->insert_new_function_version ();
 276   before = decl1_v;
 277   DECL_FUNCTION_VERSIONED (node->decl) = 1;
 278
 279   for (i = 0; i < attrnum; i++)
 280     {
 281       char *attr = attrs[i];
 282       char *suffix = XNEWVEC (char, strlen (attr) + 1);
 283
 284       create_new_asm_name (attr, suffix);
 285       /* Create new target clone.  */
 286       cgraph_node *new_node = create_target_clone (node, definition, suffix);
 287       new_node->local.local = false;
 288       XDELETEVEC (suffix);
 289
 290       /* Set new attribute for the clone.  */
 291       tree attributes = make_attribute ("target", attr,
 292                                         DECL_ATTRIBUTES (new_node->decl));
 293       DECL_ATTRIBUTES (new_node->decl) = attributes;
 294       location_t saved_loc = input_location;
 295       input_location = DECL_SOURCE_LOCATION (node->decl);
 296       if (!targetm.target_option.valid_attribute_p (new_node->decl, NULL,
 297                                                     TREE_VALUE (attributes),
 298                                                     0))
 299         {
 300           input_location = saved_loc;
 301           continue;
 302         }
 303
 304       input_location = saved_loc;
 305       decl2_v = new_node->function_version ();
 306       if (decl2_v != NULL)
 307         continue;
 308       decl2_v = new_node->insert_new_function_version ();
 309
 310       /* Chain decl2_v and decl1_v.  All semantically identical versions
 311          will be chained together.  */
 312       after = decl2_v;
 313       while (before->next != NULL)
 314         before = before->next;
 315       while (after->prev != NULL)
 316         after = after->prev;
 317
 318       before->next = after;
 319       after->prev = before;
 320       DECL_FUNCTION_VERSIONED (new_node->decl) = 1;
 321     }
 322
 323   XDELETEVEC (attrs);
 324   XDELETEVEC (attr_str);
 325
 326   /* Setting new attribute to initial function.  */
 327   tree attributes = make_attribute ("target", "default",
 328                                     DECL_ATTRIBUTES (node->decl));
 329   DECL_ATTRIBUTES (node->decl) = attributes;
 330   location_t saved_loc = input_location;
 331   input_location = DECL_SOURCE_LOCATION (node->decl);
 332   bool ret
 333     = targetm.target_option.valid_attribute_p (node->decl, NULL,
 334                                                TREE_VALUE (attributes), 0);
 335   input_location = saved_loc;
 336   return ret;
 337 }
 338
 339 static unsigned int
 340 ipa_target_clone (void)
 341 {
 342   struct cgraph_node *node;
 343
 344   bool target_clone_pass = false;
 345   FOR_EACH_FUNCTION (node)
 346     target_clone_pass |= expand_target_clones (node, node->definition);
 347
 348   if (target_clone_pass)
 349     FOR_EACH_FUNCTION (node)
 350       create_dispatcher_calls (node);
 351
 352   return 0;
 353 }
 354
 355 namespace {
 356
 357 const pass_data pass_data_target_clone =
 358 {
 359   SIMPLE_IPA_PASS,              /* type */
 360   "targetclone",                /* name */
 361   OPTGROUP_NONE,                /* optinfo_flags */
 362   TV_NONE,                      /* tv_id */
 363   ( PROP_ssa | PROP_cfg ),      /* properties_required */
 364   0,                            /* properties_provided */
 365   0,                            /* properties_destroyed */
 366   0,                            /* todo_flags_start */
 367   TODO_update_ssa               /* todo_flags_finish */
 368 };
 369
 370 class pass_target_clone : public simple_ipa_opt_pass
 371 {
 372 public:
 373   pass_target_clone (gcc::context *ctxt)
 374     : simple_ipa_opt_pass (pass_data_target_clone, ctxt)
 375   {}
 376
 377   /* opt_pass methods: */
 378   virtual bool gate (function *);
 379   virtual unsigned int execute (function *) { return ipa_target_clone (); }
 380 };
 381
 382 bool
 383 pass_target_clone::gate (function *)
 384 {
 385   return true;
 386 }
 387
 388 } // anon namespace
 389
 390 simple_ipa_opt_pass *
 391 make_pass_target_clone (gcc::context *ctxt)
 392 {
 393   return new pass_target_clone (ctxt);
 394 }