Daily bump.
[official-gcc.git] / gcc / c-pragma.c
bloba0a99fdd96402acb196100837125dc7a8e8c814b
1 /* Handle #pragma, system V.4 style. Supports #pragma weak and #pragma pack.
2 Copyright (C) 1992, 1997, 1998, 1999, 2000, 2001, 2002
3 Free Software Foundation, Inc.
5 This file is part of GCC.
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.
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.
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, 59 Temple Place - Suite 330, Boston, MA
20 02111-1307, USA. */
22 #include "config.h"
23 #include "system.h"
24 #include "rtl.h"
25 #include "tree.h"
26 #include "function.h"
27 #include "cpplib.h"
28 #include "c-pragma.h"
29 #include "flags.h"
30 #include "toplev.h"
31 #include "ggc.h"
32 #include "c-lex.h"
33 #include "c-common.h"
34 #include "output.h"
35 #include "tm_p.h"
37 #define GCC_BAD(msgid) do { warning (msgid); return; } while (0)
38 #define GCC_BAD2(msgid, arg) do { warning (msgid, arg); return; } while (0)
40 #ifdef HANDLE_PRAGMA_PACK
41 static void handle_pragma_pack PARAMS ((cpp_reader *));
43 #ifdef HANDLE_PRAGMA_PACK_PUSH_POP
44 typedef struct align_stack
46 int alignment;
47 unsigned int num_pushes;
48 tree id;
49 struct align_stack * prev;
50 } align_stack;
52 static struct align_stack * alignment_stack = NULL;
54 /* If we have a "global" #pragma pack(<n>) in effect when the first
55 #pragma pack(push,<n>) is encountered, this stores the value of
56 maximum_field_alignment in effect. When the final pop_alignment()
57 happens, we restore the value to this, not to a value of 0 for
58 maximum_field_alignment. Value is in bits. */
59 static int default_alignment;
60 #define SET_GLOBAL_ALIGNMENT(ALIGN) \
61 (default_alignment = maximum_field_alignment = (ALIGN))
63 static void push_alignment PARAMS ((int, tree));
64 static void pop_alignment PARAMS ((tree));
65 static void mark_align_stack PARAMS ((void *));
67 /* Push an alignment value onto the stack. */
68 static void
69 push_alignment (alignment, id)
70 int alignment;
71 tree id;
73 if (alignment_stack == NULL
74 || alignment_stack->alignment != alignment
75 || id != NULL_TREE)
77 align_stack * entry;
79 entry = (align_stack *) xmalloc (sizeof (* entry));
81 entry->alignment = alignment;
82 entry->num_pushes = 1;
83 entry->id = id;
84 entry->prev = alignment_stack;
86 /* The current value of maximum_field_alignment is not necessarily
87 0 since there may be a #pragma pack(<n>) in effect; remember it
88 so that we can restore it after the final #pragma pop(). */
89 if (alignment_stack == NULL)
90 default_alignment = maximum_field_alignment;
92 alignment_stack = entry;
94 maximum_field_alignment = alignment;
96 else
97 alignment_stack->num_pushes ++;
100 /* Undo a push of an alignment onto the stack. */
101 static void
102 pop_alignment (id)
103 tree id;
105 align_stack * entry;
107 if (alignment_stack == NULL)
109 warning ("\
110 #pragma pack (pop) encountered without matching #pragma pack (push, <n>)"
112 return;
115 /* If we got an identifier, strip away everything above the target
116 entry so that the next step will restore the state just below it. */
117 if (id)
119 for (entry = alignment_stack; entry; entry = entry->prev)
120 if (entry->id == id)
122 entry->num_pushes = 1;
123 alignment_stack = entry;
124 break;
126 if (entry == NULL)
127 warning ("\
128 #pragma pack(pop, %s) encountered without matching #pragma pack(push, %s, <n>)"
129 , IDENTIFIER_POINTER (id), IDENTIFIER_POINTER (id));
132 if (-- alignment_stack->num_pushes == 0)
134 entry = alignment_stack->prev;
136 if (entry == NULL)
137 maximum_field_alignment = default_alignment;
138 else
139 maximum_field_alignment = entry->alignment;
141 free (alignment_stack);
143 alignment_stack = entry;
147 static void
148 mark_align_stack (p)
149 void *p;
151 align_stack *a = *(align_stack **) p;
153 while (a)
155 ggc_mark_tree (a->id);
156 a = a->prev;
159 #else /* not HANDLE_PRAGMA_PACK_PUSH_POP */
160 #define SET_GLOBAL_ALIGNMENT(ALIGN) (maximum_field_alignment = (ALIGN))
161 #define push_alignment(ID, N) \
162 GCC_BAD("#pragma pack(push[, id], <n>) is not supported on this target")
163 #define pop_alignment(ID) \
164 GCC_BAD("#pragma pack(pop[, id], <n>) is not supported on this target")
165 #endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
167 /* #pragma pack ()
168 #pragma pack (N)
170 #pragma pack (push, N)
171 #pragma pack (push, ID, N)
172 #pragma pack (pop)
173 #pragma pack (pop, ID) */
174 static void
175 handle_pragma_pack (dummy)
176 cpp_reader *dummy ATTRIBUTE_UNUSED;
178 tree x, id = 0;
179 int align = -1;
180 enum cpp_ttype token;
181 enum { set, push, pop } action;
183 if (c_lex (&x) != CPP_OPEN_PAREN)
184 GCC_BAD ("missing '(' after '#pragma pack' - ignored");
186 token = c_lex (&x);
187 if (token == CPP_CLOSE_PAREN)
189 action = set;
190 align = 0;
192 else if (token == CPP_NUMBER)
194 align = TREE_INT_CST_LOW (x);
195 action = set;
196 if (c_lex (&x) != CPP_CLOSE_PAREN)
197 GCC_BAD ("malformed '#pragma pack' - ignored");
199 else if (token == CPP_NAME)
201 #define GCC_BAD_ACTION do { if (action == push) \
202 GCC_BAD ("malformed '#pragma pack(push[, id], <n>)' - ignored"); \
203 else \
204 GCC_BAD ("malformed '#pragma pack(pop[, id])' - ignored"); \
205 } while (0)
207 const char *op = IDENTIFIER_POINTER (x);
208 if (!strcmp (op, "push"))
209 action = push;
210 else if (!strcmp (op, "pop"))
211 action = pop;
212 else
213 GCC_BAD2 ("unknown action '%s' for '#pragma pack' - ignored", op);
215 token = c_lex (&x);
216 if (token != CPP_COMMA && action == push)
217 GCC_BAD_ACTION;
219 if (token == CPP_COMMA)
221 token = c_lex (&x);
222 if (token == CPP_NAME)
224 id = x;
225 if (action == push && c_lex (&x) != CPP_COMMA)
226 GCC_BAD_ACTION;
227 token = c_lex (&x);
230 if (action == push)
232 if (token == CPP_NUMBER)
234 align = TREE_INT_CST_LOW (x);
235 token = c_lex (&x);
237 else
238 GCC_BAD_ACTION;
242 if (token != CPP_CLOSE_PAREN)
243 GCC_BAD_ACTION;
244 #undef GCC_BAD_ACTION
246 else
247 GCC_BAD ("malformed '#pragma pack' - ignored");
249 if (c_lex (&x) != CPP_EOF)
250 warning ("junk at end of '#pragma pack'");
252 if (action != pop)
253 switch (align)
255 case 0:
256 case 1:
257 case 2:
258 case 4:
259 case 8:
260 case 16:
261 align *= BITS_PER_UNIT;
262 break;
263 default:
264 GCC_BAD2 ("alignment must be a small power of two, not %d", align);
267 switch (action)
269 case set: SET_GLOBAL_ALIGNMENT (align); break;
270 case push: push_alignment (align, id); break;
271 case pop: pop_alignment (id); break;
274 #endif /* HANDLE_PRAGMA_PACK */
276 #ifdef HANDLE_PRAGMA_WEAK
277 static void apply_pragma_weak PARAMS ((tree, tree));
278 static void handle_pragma_weak PARAMS ((cpp_reader *));
280 static tree pending_weaks;
282 static void
283 apply_pragma_weak (decl, value)
284 tree decl, value;
286 if (value)
288 value = build_string (IDENTIFIER_LENGTH (value),
289 IDENTIFIER_POINTER (value));
290 decl_attributes (&decl, build_tree_list (get_identifier ("alias"),
291 build_tree_list (NULL, value)),
295 if (SUPPORTS_WEAK && DECL_EXTERNAL (decl) && TREE_USED (decl)
296 && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
297 warning_with_decl (decl, "applying #pragma weak `%s' after first use results in unspecified behavior");
299 declare_weak (decl);
302 void
303 maybe_apply_pragma_weak (decl)
304 tree decl;
306 tree *p, t, id;
308 /* Copied from the check in set_decl_assembler_name. */
309 if (TREE_CODE (decl) == FUNCTION_DECL
310 || (TREE_CODE (decl) == VAR_DECL
311 && (TREE_STATIC (decl)
312 || DECL_EXTERNAL (decl)
313 || TREE_PUBLIC (decl))))
314 id = DECL_ASSEMBLER_NAME (decl);
315 else
316 return;
318 for (p = &pending_weaks; (t = *p) ; p = &TREE_CHAIN (t))
319 if (id == TREE_PURPOSE (t))
321 apply_pragma_weak (decl, TREE_VALUE (t));
322 *p = TREE_CHAIN (t);
323 break;
327 /* #pragma weak name [= value] */
328 static void
329 handle_pragma_weak (dummy)
330 cpp_reader *dummy ATTRIBUTE_UNUSED;
332 tree name, value, x, decl;
333 enum cpp_ttype t;
335 value = 0;
337 if (c_lex (&name) != CPP_NAME)
338 GCC_BAD ("malformed #pragma weak, ignored");
339 t = c_lex (&x);
340 if (t == CPP_EQ)
342 if (c_lex (&value) != CPP_NAME)
343 GCC_BAD ("malformed #pragma weak, ignored");
344 t = c_lex (&x);
346 if (t != CPP_EOF)
347 warning ("junk at end of #pragma weak");
349 decl = identifier_global_value (name);
350 if (decl && TREE_CODE_CLASS (TREE_CODE (decl)) == 'd')
352 apply_pragma_weak (decl, value);
353 if (value)
354 assemble_alias (decl, value);
356 else
357 pending_weaks = tree_cons (name, value, pending_weaks);
359 #else
360 void
361 maybe_apply_pragma_weak (decl)
362 tree decl ATTRIBUTE_UNUSED;
365 #endif /* HANDLE_PRAGMA_WEAK */
367 #ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
368 static void handle_pragma_redefine_extname PARAMS ((cpp_reader *));
370 static tree pending_redefine_extname;
372 /* #pragma redefined_extname oldname newname */
373 static void
374 handle_pragma_redefine_extname (dummy)
375 cpp_reader *dummy ATTRIBUTE_UNUSED;
377 tree oldname, newname, decl, x;
378 enum cpp_ttype t;
380 if (c_lex (&oldname) != CPP_NAME)
382 warning ("malformed #pragma redefine_extname, ignored");
383 return;
385 if (c_lex (&newname) != CPP_NAME)
387 warning ("malformed #pragma redefine_extname, ignored");
388 return;
390 t = c_lex (&x);
391 if (t != CPP_EOF)
392 warning ("junk at end of #pragma redefine_extname");
394 decl = identifier_global_value (oldname);
395 if (decl && TREE_CODE_CLASS (TREE_CODE (decl)) == 'd')
397 if (DECL_ASSEMBLER_NAME_SET_P (decl)
398 && DECL_ASSEMBLER_NAME (decl) != newname)
399 warning ("#pragma redefine_extname conflicts with declaration");
400 SET_DECL_ASSEMBLER_NAME (decl, newname);
402 else
403 pending_redefine_extname
404 = tree_cons (oldname, newname, pending_redefine_extname);
406 #endif
408 #ifdef HANDLE_PRAGMA_EXTERN_PREFIX
409 static void handle_pragma_extern_prefix PARAMS ((cpp_reader *));
411 static tree pragma_extern_prefix;
413 /* #pragma extern_prefix "prefix" */
414 static void
415 handle_pragma_extern_prefix (dummy)
416 cpp_reader *dummy ATTRIBUTE_UNUSED;
418 tree prefix, x;
419 enum cpp_ttype t;
421 if (c_lex (&prefix) != CPP_STRING)
423 warning ("malformed #pragma extern_prefix, ignored");
424 return;
426 t = c_lex (&x);
427 if (t != CPP_EOF)
428 warning ("junk at end of #pragma extern_prefix");
430 /* Note that the length includes the null terminator. */
431 pragma_extern_prefix = (TREE_STRING_LENGTH (prefix) > 1 ? prefix : NULL);
433 #endif
435 /* Hook from the front ends to apply the results of one of the preceeding
436 pragmas that rename variables. */
438 tree
439 maybe_apply_renaming_pragma (decl, asmname)
440 tree decl, asmname;
442 tree oldname;
444 /* Copied from the check in set_decl_assembler_name. */
445 if (TREE_CODE (decl) == FUNCTION_DECL
446 || (TREE_CODE (decl) == VAR_DECL
447 && (TREE_STATIC (decl)
448 || DECL_EXTERNAL (decl)
449 || TREE_PUBLIC (decl))))
450 oldname = DECL_ASSEMBLER_NAME (decl);
451 else
452 return asmname;
454 /* If the name begins with a *, that's a sign of an asmname attached to
455 a previous declaration. */
456 if (IDENTIFIER_POINTER (oldname)[0] == '*')
458 const char *oldasmname = IDENTIFIER_POINTER (oldname) + 1;
459 if (asmname && strcmp (TREE_STRING_POINTER (asmname), oldasmname) != 0)
460 warning ("asm declaration conficts with previous rename");
461 asmname = build_string (strlen (oldasmname), oldasmname);
464 #ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
466 tree *p, t;
468 for (p = &pending_redefine_extname; (t = *p) ; p = &TREE_CHAIN (t))
469 if (oldname == TREE_PURPOSE (t))
471 const char *newname = IDENTIFIER_POINTER (TREE_VALUE (t));
473 if (asmname && strcmp (TREE_STRING_POINTER (asmname), newname) != 0)
474 warning ("#pragma redefine_extname conflicts with declaration");
475 *p = TREE_CHAIN (t);
477 return build_string (strlen (newname), newname);
480 #endif
482 #ifdef HANDLE_PRAGMA_EXTERN_PREFIX
483 if (pragma_extern_prefix && !asmname)
485 char *x = concat (TREE_STRING_POINTER (pragma_extern_prefix),
486 IDENTIFIER_POINTER (oldname), NULL);
487 asmname = build_string (strlen (x), x);
488 free (x);
489 return asmname;
491 #endif
493 return asmname;
496 void
497 init_pragma ()
499 #ifdef HANDLE_PRAGMA_PACK
500 cpp_register_pragma (parse_in, 0, "pack", handle_pragma_pack);
501 #endif
502 #ifdef HANDLE_PRAGMA_WEAK
503 cpp_register_pragma (parse_in, 0, "weak", handle_pragma_weak);
504 ggc_add_tree_root (&pending_weaks, 1);
505 #endif
506 #ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
507 cpp_register_pragma (parse_in, 0, "redefine_extname",
508 handle_pragma_redefine_extname);
509 ggc_add_tree_root (&pending_redefine_extname, 1);
510 #endif
511 #ifdef HANDLE_PRAGMA_EXTERN_PREFIX
512 cpp_register_pragma (parse_in, 0, "extern_prefix",
513 handle_pragma_extern_prefix);
514 ggc_add_tree_root (&pragma_extern_prefix, 1);
515 #endif
517 #ifdef REGISTER_TARGET_PRAGMAS
518 REGISTER_TARGET_PRAGMAS (parse_in);
519 #endif
521 #ifdef HANDLE_PRAGMA_PACK_PUSH_POP
522 ggc_add_root (&alignment_stack, 1, sizeof(alignment_stack),
523 mark_align_stack);
524 #endif