gcc/c-pragma.c

   1 /* Handle #pragma, system V.4 style.  Supports #pragma weak and #pragma pack.
   2    Copyright (C) 1992, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "rtl.h"
  27 #include "tree.h"
  28 #include "function.h"
  29 #include "cpplib.h"
  30 #include "c-pragma.h"
  31 #include "flags.h"
  32 #include "toplev.h"
  33 #include "ggc.h"
  34 #include "c-common.h"
  35 #include "output.h"
  36 #include "tm_p.h"
  37 #include "vec.h"
  38 #include "target.h"
  39
  40
  41 #define GCC_BAD(gmsgid) \
  42   do { warning (OPT_Wpragmas, gmsgid); return; } while (0)
  43 #define GCC_BAD2(gmsgid, arg) \
  44   do { warning (OPT_Wpragmas, gmsgid, arg); return; } while (0)
  45
  46 typedef struct align_stack GTY(())
  47 {
  48   int                  alignment;
  49   tree                 id;
  50   struct align_stack * prev;
  51 } align_stack;
  52
  53 static GTY(()) struct align_stack * alignment_stack;
  54
  55 #ifdef HANDLE_PRAGMA_PACK
  56 static void handle_pragma_pack (cpp_reader *);
  57
  58 #ifdef HANDLE_PRAGMA_PACK_PUSH_POP
  59 /* If we have a "global" #pragma pack(<n>) in effect when the first
  60    #pragma pack(push,<n>) is encountered, this stores the value of
  61    maximum_field_alignment in effect.  When the final pop_alignment()
  62    happens, we restore the value to this, not to a value of 0 for
  63    maximum_field_alignment.  Value is in bits.  */
  64 static int default_alignment;
  65 #define SET_GLOBAL_ALIGNMENT(ALIGN) (maximum_field_alignment = *(alignment_stack == NULL \
  66         ? &default_alignment \
  67         : &alignment_stack->alignment) = (ALIGN))
  68
  69 static void push_alignment (int, tree);
  70 static void pop_alignment (tree);
  71
  72 /* Push an alignment value onto the stack.  */
  73 static void
  74 push_alignment (int alignment, tree id)
  75 {
  76   align_stack * entry;
  77
  78   entry = GGC_NEW (align_stack);
  79
  80   entry->alignment  = alignment;
  81   entry->id         = id;
  82   entry->prev       = alignment_stack;
  83
  84   /* The current value of maximum_field_alignment is not necessarily
  85      0 since there may be a #pragma pack(<n>) in effect; remember it
  86      so that we can restore it after the final #pragma pop().  */
  87   if (alignment_stack == NULL)
  88     default_alignment = maximum_field_alignment;
  89
  90   alignment_stack = entry;
  91
  92   maximum_field_alignment = alignment;
  93 }
  94
  95 /* Undo a push of an alignment onto the stack.  */
  96 static void
  97 pop_alignment (tree id)
  98 {
  99   align_stack * entry;
 100
 101   if (alignment_stack == NULL)
 102     GCC_BAD ("#pragma pack (pop) encountered without matching #pragma pack (push)");
 103
 104   /* If we got an identifier, strip away everything above the target
 105      entry so that the next step will restore the state just below it.  */
 106   if (id)
 107     {
 108       for (entry = alignment_stack; entry; entry = entry->prev)
 109         if (entry->id == id)
 110           {
 111             alignment_stack = entry;
 112             break;
 113           }
 114       if (entry == NULL)
 115         warning (OPT_Wpragmas, "\
 116 #pragma pack(pop, %s) encountered without matching #pragma pack(push, %s)"
 117                  , IDENTIFIER_POINTER (id), IDENTIFIER_POINTER (id));
 118     }
 119
 120   entry = alignment_stack->prev;
 121
 122   maximum_field_alignment = entry ? entry->alignment : default_alignment;
 123
 124   alignment_stack = entry;
 125 }
 126 #else  /* not HANDLE_PRAGMA_PACK_PUSH_POP */
 127 #define SET_GLOBAL_ALIGNMENT(ALIGN) (maximum_field_alignment = (ALIGN))
 128 #define push_alignment(ID, N) \
 129     GCC_BAD ("#pragma pack(push[, id], <n>) is not supported on this target")
 130 #define pop_alignment(ID) \
 131     GCC_BAD ("#pragma pack(pop[, id], <n>) is not supported on this target")
 132 #endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
 133
 134 /* #pragma pack ()
 135    #pragma pack (N)
 136
 137    #pragma pack (push)
 138    #pragma pack (push, N)
 139    #pragma pack (push, ID)
 140    #pragma pack (push, ID, N)
 141    #pragma pack (pop)
 142    #pragma pack (pop, ID) */
 143 static void
 144 handle_pragma_pack (cpp_reader * ARG_UNUSED (dummy))
 145 {
 146   tree x, id = 0;
 147   int align = -1;
 148   enum cpp_ttype token;
 149   enum { set, push, pop } action;
 150
 151   if (pragma_lex (&x) != CPP_OPEN_PAREN)
 152     GCC_BAD ("missing %<(%> after %<#pragma pack%> - ignored");
 153
 154   token = pragma_lex (&x);
 155   if (token == CPP_CLOSE_PAREN)
 156     {
 157       action = set;
 158       align = initial_max_fld_align;
 159     }
 160   else if (token == CPP_NUMBER)
 161     {
 162       align = TREE_INT_CST_LOW (x);
 163       action = set;
 164       if (pragma_lex (&x) != CPP_CLOSE_PAREN)
 165         GCC_BAD ("malformed %<#pragma pack%> - ignored");
 166     }
 167   else if (token == CPP_NAME)
 168     {
 169 #define GCC_BAD_ACTION do { if (action != pop) \
 170           GCC_BAD ("malformed %<#pragma pack(push[, id][, <n>])%> - ignored"); \
 171         else \
 172           GCC_BAD ("malformed %<#pragma pack(pop[, id])%> - ignored"); \
 173         } while (0)
 174
 175       const char *op = IDENTIFIER_POINTER (x);
 176       if (!strcmp (op, "push"))
 177         action = push;
 178       else if (!strcmp (op, "pop"))
 179         action = pop;
 180       else
 181         GCC_BAD2 ("unknown action %qs for %<#pragma pack%> - ignored", op);
 182
 183       while ((token = pragma_lex (&x)) == CPP_COMMA)
 184         {
 185           token = pragma_lex (&x);
 186           if (token == CPP_NAME && id == 0)
 187             {
 188               id = x;
 189             }
 190           else if (token == CPP_NUMBER && action == push && align == -1)
 191             {
 192               align = TREE_INT_CST_LOW (x);
 193               if (align == -1)
 194                 action = set;
 195             }
 196           else
 197             GCC_BAD_ACTION;
 198         }
 199
 200       if (token != CPP_CLOSE_PAREN)
 201         GCC_BAD_ACTION;
 202 #undef GCC_BAD_ACTION
 203     }
 204   else
 205     GCC_BAD ("malformed %<#pragma pack%> - ignored");
 206
 207   if (pragma_lex (&x) != CPP_EOF)
 208     warning (OPT_Wpragmas, "junk at end of %<#pragma pack%>");
 209
 210   if (flag_pack_struct)
 211     GCC_BAD ("#pragma pack has no effect with -fpack-struct - ignored");
 212
 213   if (action != pop)
 214     switch (align)
 215       {
 216       case 0:
 217       case 1:
 218       case 2:
 219       case 4:
 220       case 8:
 221       case 16:
 222         align *= BITS_PER_UNIT;
 223         break;
 224       case -1:
 225         if (action == push)
 226           {
 227             align = maximum_field_alignment;
 228             break;
 229           }
 230       default:
 231         GCC_BAD2 ("alignment must be a small power of two, not %d", align);
 232       }
 233
 234   switch (action)
 235     {
 236     case set:   SET_GLOBAL_ALIGNMENT (align);  break;
 237     case push:  push_alignment (align, id);    break;
 238     case pop:   pop_alignment (id);            break;
 239     }
 240 }
 241 #endif  /* HANDLE_PRAGMA_PACK */
 242
 243 static GTY(()) tree pending_weaks;
 244
 245 #ifdef HANDLE_PRAGMA_WEAK
 246 static void apply_pragma_weak (tree, tree);
 247 static void handle_pragma_weak (cpp_reader *);
 248
 249 static void
 250 apply_pragma_weak (tree decl, tree value)
 251 {
 252   if (value)
 253     {
 254       value = build_string (IDENTIFIER_LENGTH (value),
 255                             IDENTIFIER_POINTER (value));
 256       decl_attributes (&decl, build_tree_list (get_identifier ("alias"),
 257                                                build_tree_list (NULL, value)),
 258                        0);
 259     }
 260
 261   if (SUPPORTS_WEAK && DECL_EXTERNAL (decl) && TREE_USED (decl)
 262       && !DECL_WEAK (decl) /* Don't complain about a redundant #pragma.  */
 263       && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
 264     warning (OPT_Wpragmas, "applying #pragma weak %q+D after first use "
 265              "results in unspecified behavior", decl);
 266
 267   declare_weak (decl);
 268 }
 269
 270 void
 271 maybe_apply_pragma_weak (tree decl)
 272 {
 273   tree *p, t, id;
 274
 275   /* Avoid asking for DECL_ASSEMBLER_NAME when it's not needed.  */
 276
 277   /* No weak symbols pending, take the short-cut.  */
 278   if (!pending_weaks)
 279     return;
 280   /* If it's not visible outside this file, it doesn't matter whether
 281      it's weak.  */
 282   if (!DECL_EXTERNAL (decl) && !TREE_PUBLIC (decl))
 283     return;
 284   /* If it's not a function or a variable, it can't be weak.
 285      FIXME: what kinds of things are visible outside this file but
 286      aren't functions or variables?   Should this be an assert instead?  */
 287   if (TREE_CODE (decl) != FUNCTION_DECL && TREE_CODE (decl) != VAR_DECL)
 288     return;
 289
 290   id = DECL_ASSEMBLER_NAME (decl);
 291
 292   for (p = &pending_weaks; (t = *p) ; p = &TREE_CHAIN (t))
 293     if (id == TREE_PURPOSE (t))
 294       {
 295         apply_pragma_weak (decl, TREE_VALUE (t));
 296         *p = TREE_CHAIN (t);
 297         break;
 298       }
 299 }
 300
 301 /* Process all "#pragma weak A = B" directives where we have not seen
 302    a decl for A.  */
 303 void
 304 maybe_apply_pending_pragma_weaks (void)
 305 {
 306   tree *p, t, alias_id, id, decl, *next;
 307
 308   for (p = &pending_weaks; (t = *p) ; p = next)
 309     {
 310       next = &TREE_CHAIN (t);
 311       alias_id = TREE_PURPOSE (t);
 312       id = TREE_VALUE (t);
 313
 314       if (TREE_VALUE (t) == NULL)
 315         continue;
 316
 317       decl = build_decl (FUNCTION_DECL, alias_id, default_function_type);
 318
 319       DECL_ARTIFICIAL (decl) = 1;
 320       TREE_PUBLIC (decl) = 1;
 321       DECL_EXTERNAL (decl) = 1;
 322       DECL_WEAK (decl) = 1;
 323
 324       assemble_alias (decl, id);
 325     }
 326 }
 327
 328 /* #pragma weak name [= value] */
 329 static void
 330 handle_pragma_weak (cpp_reader * ARG_UNUSED (dummy))
 331 {
 332   tree name, value, x, decl;
 333   enum cpp_ttype t;
 334
 335   value = 0;
 336
 337   if (pragma_lex (&name) != CPP_NAME)
 338     GCC_BAD ("malformed #pragma weak, ignored");
 339   t = pragma_lex (&x);
 340   if (t == CPP_EQ)
 341     {
 342       if (pragma_lex (&value) != CPP_NAME)
 343         GCC_BAD ("malformed #pragma weak, ignored");
 344       t = pragma_lex (&x);
 345     }
 346   if (t != CPP_EOF)
 347     warning (OPT_Wpragmas, "junk at end of %<#pragma weak%>");
 348
 349   decl = identifier_global_value (name);
 350   if (decl && DECL_P (decl))
 351     {
 352       apply_pragma_weak (decl, value);
 353       if (value)
 354         assemble_alias (decl, value);
 355     }
 356   else
 357     pending_weaks = tree_cons (name, value, pending_weaks);
 358 }
 359 #else
 360 void
 361 maybe_apply_pragma_weak (tree ARG_UNUSED (decl))
 362 {
 363 }
 364
 365 void
 366 maybe_apply_pending_pragma_weaks (void)
 367 {
 368 }
 369 #endif /* HANDLE_PRAGMA_WEAK */
 370
 371 /* GCC supports two #pragma directives for renaming the external
 372    symbol associated with a declaration (DECL_ASSEMBLER_NAME), for
 373    compatibility with the Solaris and Tru64 system headers.  GCC also
 374    has its own notation for this, __asm__("name") annotations.
 375
 376    Corner cases of these features and their interaction:
 377
 378    1) Both pragmas silently apply only to declarations with external
 379       linkage (that is, TREE_PUBLIC || DECL_EXTERNAL).  Asm labels
 380       do not have this restriction.
 381
 382    2) In C++, both #pragmas silently apply only to extern "C" declarations.
 383       Asm labels do not have this restriction.
 384
 385    3) If any of the three ways of changing DECL_ASSEMBLER_NAME is
 386       applied to a decl whose DECL_ASSEMBLER_NAME is already set, and the
 387       new name is different, a warning issues and the name does not change.
 388
 389    4) The "source name" for #pragma redefine_extname is the DECL_NAME,
 390       *not* the DECL_ASSEMBLER_NAME.
 391
 392    5) If #pragma extern_prefix is in effect and a declaration occurs
 393       with an __asm__ name, the #pragma extern_prefix is silently
 394       ignored for that declaration.
 395
 396    6) If #pragma extern_prefix and #pragma redefine_extname apply to
 397       the same declaration, whichever triggered first wins, and a warning
 398       is issued.  (We would like to have #pragma redefine_extname always
 399       win, but it can appear either before or after the declaration, and
 400       if it appears afterward, we have no way of knowing whether a modified
 401       DECL_ASSEMBLER_NAME is due to #pragma extern_prefix.)  */
 402
 403 static GTY(()) tree pending_redefine_extname;
 404
 405 static void handle_pragma_redefine_extname (cpp_reader *);
 406
 407 /* #pragma redefine_extname oldname newname */
 408 static void
 409 handle_pragma_redefine_extname (cpp_reader * ARG_UNUSED (dummy))
 410 {
 411   tree oldname, newname, decl, x;
 412   enum cpp_ttype t;
 413
 414   if (pragma_lex (&oldname) != CPP_NAME)
 415     GCC_BAD ("malformed #pragma redefine_extname, ignored");
 416   if (pragma_lex (&newname) != CPP_NAME)
 417     GCC_BAD ("malformed #pragma redefine_extname, ignored");
 418   t = pragma_lex (&x);
 419   if (t != CPP_EOF)
 420     warning (OPT_Wpragmas, "junk at end of %<#pragma redefine_extname%>");
 421
 422   if (!flag_mudflap && !targetm.handle_pragma_redefine_extname)
 423     {
 424       if (warn_unknown_pragmas > in_system_header)
 425         warning (OPT_Wunknown_pragmas,
 426                  "#pragma redefine_extname not supported on this target");
 427       return;
 428     }
 429
 430   decl = identifier_global_value (oldname);
 431   if (decl
 432       && (TREE_PUBLIC (decl) || DECL_EXTERNAL (decl))
 433       && (TREE_CODE (decl) == FUNCTION_DECL
 434           || TREE_CODE (decl) == VAR_DECL)
 435       && has_c_linkage (decl))
 436     {
 437       if (DECL_ASSEMBLER_NAME_SET_P (decl))
 438         {
 439           const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
 440           name = targetm.strip_name_encoding (name);
 441
 442           if (strcmp (name, IDENTIFIER_POINTER (newname)))
 443             warning (OPT_Wpragmas, "#pragma redefine_extname ignored due to "
 444                      "conflict with previous rename");
 445         }
 446       else
 447         change_decl_assembler_name (decl, newname);
 448     }
 449   else
 450     /* We have to add this to the rename list even if there's already
 451        a global value that doesn't meet the above criteria, because in
 452        C++ "struct foo {...};" puts "foo" in the current namespace but
 453        does *not* conflict with a subsequent declaration of a function
 454        or variable foo.  See g++.dg/other/pragma-re-2.C.  */
 455     add_to_renaming_pragma_list (oldname, newname);
 456 }
 457
 458 /* This is called from here and from ia64.c.  */
 459 void
 460 add_to_renaming_pragma_list (tree oldname, tree newname)
 461 {
 462   tree previous = purpose_member (oldname, pending_redefine_extname);
 463   if (previous)
 464     {
 465       if (TREE_VALUE (previous) != newname)
 466         warning (OPT_Wpragmas, "#pragma redefine_extname ignored due to "
 467                  "conflict with previous #pragma redefine_extname");
 468       return;
 469     }
 470
 471   pending_redefine_extname
 472     = tree_cons (oldname, newname, pending_redefine_extname);
 473 }
 474
 475 static GTY(()) tree pragma_extern_prefix;
 476
 477 /* #pragma extern_prefix "prefix" */
 478 static void
 479 handle_pragma_extern_prefix (cpp_reader * ARG_UNUSED (dummy))
 480 {
 481   tree prefix, x;
 482   enum cpp_ttype t;
 483
 484   if (pragma_lex (&prefix) != CPP_STRING)
 485     GCC_BAD ("malformed #pragma extern_prefix, ignored");
 486   t = pragma_lex (&x);
 487   if (t != CPP_EOF)
 488     warning (OPT_Wpragmas, "junk at end of %<#pragma extern_prefix%>");
 489
 490   if (targetm.handle_pragma_extern_prefix)
 491     /* Note that the length includes the null terminator.  */
 492     pragma_extern_prefix = (TREE_STRING_LENGTH (prefix) > 1 ? prefix : NULL);
 493   else if (warn_unknown_pragmas > in_system_header)
 494     warning (OPT_Wunknown_pragmas,
 495              "#pragma extern_prefix not supported on this target");
 496 }
 497
 498 /* Hook from the front ends to apply the results of one of the preceding
 499    pragmas that rename variables.  */
 500
 501 tree
 502 maybe_apply_renaming_pragma (tree decl, tree asmname)
 503 {
 504   tree *p, t;
 505
 506   /* The renaming pragmas are only applied to declarations with
 507      external linkage.  */
 508   if ((TREE_CODE (decl) != FUNCTION_DECL && TREE_CODE (decl) != VAR_DECL)
 509       || (!TREE_PUBLIC (decl) && !DECL_EXTERNAL (decl))
 510       || !has_c_linkage (decl))
 511     return asmname;
 512
 513   /* If the DECL_ASSEMBLER_NAME is already set, it does not change,
 514      but we may warn about a rename that conflicts.  */
 515   if (DECL_ASSEMBLER_NAME_SET_P (decl))
 516     {
 517       const char *oldname = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
 518       oldname = targetm.strip_name_encoding (oldname);
 519
 520       if (asmname && strcmp (TREE_STRING_POINTER (asmname), oldname))
 521           warning (OPT_Wpragmas, "asm declaration ignored due to "
 522                    "conflict with previous rename");
 523
 524       /* Take any pending redefine_extname off the list.  */
 525       for (p = &pending_redefine_extname; (t = *p); p = &TREE_CHAIN (t))
 526         if (DECL_NAME (decl) == TREE_PURPOSE (t))
 527           {
 528             /* Only warn if there is a conflict.  */
 529             if (strcmp (IDENTIFIER_POINTER (TREE_VALUE (t)), oldname))
 530               warning (OPT_Wpragmas, "#pragma redefine_extname ignored due to "
 531                        "conflict with previous rename");
 532
 533             *p = TREE_CHAIN (t);
 534             break;
 535           }
 536       return 0;
 537     }
 538
 539   /* Find out if we have a pending #pragma redefine_extname.  */
 540   for (p = &pending_redefine_extname; (t = *p); p = &TREE_CHAIN (t))
 541     if (DECL_NAME (decl) == TREE_PURPOSE (t))
 542       {
 543         tree newname = TREE_VALUE (t);
 544         *p = TREE_CHAIN (t);
 545
 546         /* If we already have an asmname, #pragma redefine_extname is
 547            ignored (with a warning if it conflicts).  */
 548         if (asmname)
 549           {
 550             if (strcmp (TREE_STRING_POINTER (asmname),
 551                         IDENTIFIER_POINTER (newname)) != 0)
 552               warning (OPT_Wpragmas, "#pragma redefine_extname ignored due to "
 553                        "conflict with __asm__ declaration");
 554             return asmname;
 555           }
 556
 557         /* Otherwise we use what we've got; #pragma extern_prefix is
 558            silently ignored.  */
 559         return build_string (IDENTIFIER_LENGTH (newname),
 560                              IDENTIFIER_POINTER (newname));
 561       }
 562
 563   /* If we've got an asmname, #pragma extern_prefix is silently ignored.  */
 564   if (asmname)
 565     return asmname;
 566
 567   /* If #pragma extern_prefix is in effect, apply it.  */
 568   if (pragma_extern_prefix)
 569     {
 570       const char *prefix = TREE_STRING_POINTER (pragma_extern_prefix);
 571       size_t plen = TREE_STRING_LENGTH (pragma_extern_prefix) - 1;
 572
 573       const char *id = IDENTIFIER_POINTER (DECL_NAME (decl));
 574       size_t ilen = IDENTIFIER_LENGTH (DECL_NAME (decl));
 575
 576       char *newname = (char *) alloca (plen + ilen + 1);
 577
 578       memcpy (newname,        prefix, plen);
 579       memcpy (newname + plen, id, ilen + 1);
 580
 581       return build_string (plen + ilen, newname);
 582     }
 583
 584   /* Nada.  */
 585   return 0;
 586 }
 587
 588
 589 #ifdef HANDLE_PRAGMA_VISIBILITY
 590 static void handle_pragma_visibility (cpp_reader *);
 591
 592 typedef enum symbol_visibility visibility;
 593 DEF_VEC_I (visibility);
 594 DEF_VEC_ALLOC_I (visibility, heap);
 595
 596 /* Sets the default visibility for symbols to something other than that
 597    specified on the command line.  */
 598 static void
 599 handle_pragma_visibility (cpp_reader *dummy ATTRIBUTE_UNUSED)
 600 {
 601   /* Form is #pragma GCC visibility push(hidden)|pop */
 602   tree x;
 603   enum cpp_ttype token;
 604   enum { bad, push, pop } action = bad;
 605   static VEC (visibility, heap) *visstack;
 606
 607   token = pragma_lex (&x);
 608   if (token == CPP_NAME)
 609     {
 610       const char *op = IDENTIFIER_POINTER (x);
 611       if (!strcmp (op, "push"))
 612         action = push;
 613       else if (!strcmp (op, "pop"))
 614         action = pop;
 615     }
 616   if (bad == action)
 617     GCC_BAD ("#pragma GCC visibility must be followed by push or pop");
 618   else
 619     {
 620       if (pop == action)
 621         {
 622           if (!VEC_length (visibility, visstack))
 623             {
 624               GCC_BAD ("no matching push for %<#pragma GCC visibility pop%>");
 625             }
 626           else
 627             {
 628               default_visibility = VEC_pop (visibility, visstack);
 629               visibility_options.inpragma
 630                 = VEC_length (visibility, visstack) != 0;
 631             }
 632         }
 633       else
 634         {
 635           if (pragma_lex (&x) != CPP_OPEN_PAREN)
 636             GCC_BAD ("missing %<(%> after %<#pragma GCC visibility push%> - ignored");
 637           token = pragma_lex (&x);
 638           if (token != CPP_NAME)
 639             {
 640               GCC_BAD ("malformed #pragma GCC visibility push");
 641             }
 642           else
 643             {
 644               const char *str = IDENTIFIER_POINTER (x);
 645               VEC_safe_push (visibility, heap, visstack,
 646                              default_visibility);
 647               if (!strcmp (str, "default"))
 648                 default_visibility = VISIBILITY_DEFAULT;
 649               else if (!strcmp (str, "internal"))
 650                 default_visibility = VISIBILITY_INTERNAL;
 651               else if (!strcmp (str, "hidden"))
 652                 default_visibility = VISIBILITY_HIDDEN;
 653               else if (!strcmp (str, "protected"))
 654                 default_visibility = VISIBILITY_PROTECTED;
 655               else
 656                 {
 657                   GCC_BAD ("#pragma GCC visibility push() must specify default, internal, hidden or protected");
 658                 }
 659               visibility_options.inpragma = 1;
 660             }
 661           if (pragma_lex (&x) != CPP_CLOSE_PAREN)
 662             GCC_BAD ("missing %<(%> after %<#pragma GCC visibility push%> - ignored");
 663         }
 664     }
 665   if (pragma_lex (&x) != CPP_EOF)
 666     warning (OPT_Wpragmas, "junk at end of %<#pragma GCC visibility%>");
 667 }
 668
 669 #endif
 670
 671 /* A vector of registered pragma callbacks.  */
 672
 673 DEF_VEC_O (pragma_handler);
 674 DEF_VEC_ALLOC_O (pragma_handler, heap);
 675
 676 static VEC(pragma_handler, heap) *registered_pragmas;
 677
 678 /* Front-end wrappers for pragma registration to avoid dragging
 679    cpplib.h in almost everywhere.  */
 680
 681 static void
 682 c_register_pragma_1 (const char *space, const char *name,
 683                      pragma_handler handler, bool allow_expansion)
 684 {
 685   unsigned id;
 686
 687   VEC_safe_push (pragma_handler, heap, registered_pragmas, &handler);
 688   id = VEC_length (pragma_handler, registered_pragmas);
 689   id += PRAGMA_FIRST_EXTERNAL - 1;
 690
 691   /* The C++ front end allocates 6 bits in cp_token; the C front end
 692      allocates 7 bits in c_token.  At present this is sufficient.  */
 693   gcc_assert (id < 64);
 694
 695   cpp_register_deferred_pragma (parse_in, space, name, id,
 696                                 allow_expansion, false);
 697 }
 698
 699 void
 700 c_register_pragma (const char *space, const char *name, pragma_handler handler)
 701 {
 702   c_register_pragma_1 (space, name, handler, false);
 703 }
 704
 705 void
 706 c_register_pragma_with_expansion (const char *space, const char *name,
 707                                   pragma_handler handler)
 708 {
 709   c_register_pragma_1 (space, name, handler, true);
 710 }
 711
 712 void
 713 c_invoke_pragma_handler (unsigned int id)
 714 {
 715   pragma_handler handler;
 716
 717   id -= PRAGMA_FIRST_EXTERNAL;
 718   handler = *VEC_index (pragma_handler, registered_pragmas, id);
 719
 720   handler (parse_in);
 721 }
 722
 723 /* Set up front-end pragmas.  */
 724 void
 725 init_pragma (void)
 726 {
 727   cpp_register_deferred_pragma (parse_in, "GCC", "pch_preprocess",
 728                                 PRAGMA_GCC_PCH_PREPROCESS, false, false);
 729
 730 #ifdef HANDLE_PRAGMA_PACK
 731 #ifdef HANDLE_PRAGMA_PACK_WITH_EXPANSION
 732   c_register_pragma_with_expansion (0, "pack", handle_pragma_pack);
 733 #else
 734   c_register_pragma (0, "pack", handle_pragma_pack);
 735 #endif
 736 #endif
 737 #ifdef HANDLE_PRAGMA_WEAK
 738   c_register_pragma (0, "weak", handle_pragma_weak);
 739 #endif
 740 #ifdef HANDLE_PRAGMA_VISIBILITY
 741   c_register_pragma ("GCC", "visibility", handle_pragma_visibility);
 742 #endif
 743
 744   c_register_pragma (0, "redefine_extname", handle_pragma_redefine_extname);
 745   c_register_pragma (0, "extern_prefix", handle_pragma_extern_prefix);
 746
 747 #ifdef REGISTER_TARGET_PRAGMAS
 748   REGISTER_TARGET_PRAGMAS ();
 749 #endif
 750 }
 751
 752 #include "gt-c-pragma.h"