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
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
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
36 #define GCC_BAD(msgid) do { warning (msgid); return; } while (0)
37 #define GCC_BAD2(msgid, arg) do { warning (msgid, arg); return; } while (0)
39 typedef struct align_stack GTY(())
42 unsigned int num_pushes;
44 struct align_stack * prev;
47 static GTY(()) struct align_stack * alignment_stack;
49 #ifdef HANDLE_PRAGMA_PACK
50 static void handle_pragma_pack PARAMS ((cpp_reader *));
52 #ifdef HANDLE_PRAGMA_PACK_PUSH_POP
53 /* If we have a "global" #pragma pack(<n>) in effect when the first
54 #pragma pack(push,<n>) is encountered, this stores the value of
55 maximum_field_alignment in effect. When the final pop_alignment()
56 happens, we restore the value to this, not to a value of 0 for
57 maximum_field_alignment. Value is in bits. */
58 static int default_alignment;
59 #define SET_GLOBAL_ALIGNMENT(ALIGN) \
60 (default_alignment = maximum_field_alignment = (ALIGN))
62 static void push_alignment PARAMS ((int, tree));
63 static void pop_alignment PARAMS ((tree));
65 /* Push an alignment value onto the stack. */
67 push_alignment (alignment, id)
71 if (alignment_stack == NULL
72 || alignment_stack->alignment != alignment
77 entry = (align_stack *) ggc_alloc (sizeof (* entry));
79 entry->alignment = alignment;
80 entry->num_pushes = 1;
82 entry->prev = alignment_stack;
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;
90 alignment_stack = entry;
92 maximum_field_alignment = alignment;
95 alignment_stack->num_pushes ++;
98 /* Undo a push of an alignment onto the stack. */
105 if (alignment_stack == NULL)
108 #pragma pack (pop) encountered without matching #pragma pack (push, <n>)"
113 /* If we got an identifier, strip away everything above the target
114 entry so that the next step will restore the state just below it. */
117 for (entry = alignment_stack; entry; entry = entry->prev)
120 entry->num_pushes = 1;
121 alignment_stack = entry;
126 #pragma pack(pop, %s) encountered without matching #pragma pack(push, %s, <n>)"
127 , IDENTIFIER_POINTER (id), IDENTIFIER_POINTER (id));
130 if (-- alignment_stack->num_pushes == 0)
132 entry = alignment_stack->prev;
135 maximum_field_alignment = default_alignment;
137 maximum_field_alignment = entry->alignment;
139 alignment_stack = entry;
142 #else /* not HANDLE_PRAGMA_PACK_PUSH_POP */
143 #define SET_GLOBAL_ALIGNMENT(ALIGN) (maximum_field_alignment = (ALIGN))
144 #define push_alignment(ID, N) \
145 GCC_BAD("#pragma pack(push[, id], <n>) is not supported on this target")
146 #define pop_alignment(ID) \
147 GCC_BAD("#pragma pack(pop[, id], <n>) is not supported on this target")
148 #endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
153 #pragma pack (push, N)
154 #pragma pack (push, ID, N)
156 #pragma pack (pop, ID) */
158 handle_pragma_pack (dummy)
159 cpp_reader *dummy ATTRIBUTE_UNUSED;
163 enum cpp_ttype token;
164 enum { set, push, pop } action;
166 if (c_lex (&x) != CPP_OPEN_PAREN)
167 GCC_BAD ("missing '(' after '#pragma pack' - ignored");
170 if (token == CPP_CLOSE_PAREN)
175 else if (token == CPP_NUMBER)
177 align = TREE_INT_CST_LOW (x);
179 if (c_lex (&x) != CPP_CLOSE_PAREN)
180 GCC_BAD ("malformed '#pragma pack' - ignored");
182 else if (token == CPP_NAME)
184 #define GCC_BAD_ACTION do { if (action == push) \
185 GCC_BAD ("malformed '#pragma pack(push[, id], <n>)' - ignored"); \
187 GCC_BAD ("malformed '#pragma pack(pop[, id])' - ignored"); \
190 const char *op = IDENTIFIER_POINTER (x);
191 if (!strcmp (op, "push"))
193 else if (!strcmp (op, "pop"))
196 GCC_BAD2 ("unknown action '%s' for '#pragma pack' - ignored", op);
199 if (token != CPP_COMMA && action == push)
202 if (token == CPP_COMMA)
205 if (token == CPP_NAME)
208 if (action == push && c_lex (&x) != CPP_COMMA)
215 if (token == CPP_NUMBER)
217 align = TREE_INT_CST_LOW (x);
225 if (token != CPP_CLOSE_PAREN)
227 #undef GCC_BAD_ACTION
230 GCC_BAD ("malformed '#pragma pack' - ignored");
232 if (c_lex (&x) != CPP_EOF)
233 warning ("junk at end of '#pragma pack'");
244 align *= BITS_PER_UNIT;
247 GCC_BAD2 ("alignment must be a small power of two, not %d", align);
252 case set: SET_GLOBAL_ALIGNMENT (align); break;
253 case push: push_alignment (align, id); break;
254 case pop: pop_alignment (id); break;
257 #endif /* HANDLE_PRAGMA_PACK */
259 static GTY(()) tree pending_weaks;
261 #ifdef HANDLE_PRAGMA_WEAK
262 static void apply_pragma_weak PARAMS ((tree, tree));
263 static void handle_pragma_weak PARAMS ((cpp_reader *));
266 apply_pragma_weak (decl, value)
271 value = build_string (IDENTIFIER_LENGTH (value),
272 IDENTIFIER_POINTER (value));
273 decl_attributes (&decl, build_tree_list (get_identifier ("alias"),
274 build_tree_list (NULL, value)),
278 if (SUPPORTS_WEAK && DECL_EXTERNAL (decl) && TREE_USED (decl)
279 && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
280 warning_with_decl (decl, "applying #pragma weak `%s' after first use results in unspecified behavior");
286 maybe_apply_pragma_weak (decl)
291 /* Copied from the check in set_decl_assembler_name. */
292 if (TREE_CODE (decl) == FUNCTION_DECL
293 || (TREE_CODE (decl) == VAR_DECL
294 && (TREE_STATIC (decl)
295 || DECL_EXTERNAL (decl)
296 || TREE_PUBLIC (decl))))
297 id = DECL_ASSEMBLER_NAME (decl);
301 for (p = &pending_weaks; (t = *p) ; p = &TREE_CHAIN (t))
302 if (id == TREE_PURPOSE (t))
304 apply_pragma_weak (decl, TREE_VALUE (t));
310 /* #pragma weak name [= value] */
312 handle_pragma_weak (dummy)
313 cpp_reader *dummy ATTRIBUTE_UNUSED;
315 tree name, value, x, decl;
320 if (c_lex (&name) != CPP_NAME)
321 GCC_BAD ("malformed #pragma weak, ignored");
325 if (c_lex (&value) != CPP_NAME)
326 GCC_BAD ("malformed #pragma weak, ignored");
330 warning ("junk at end of #pragma weak");
332 decl = identifier_global_value (name);
333 if (decl && TREE_CODE_CLASS (TREE_CODE (decl)) == 'd')
335 apply_pragma_weak (decl, value);
337 assemble_alias (decl, value);
340 pending_weaks = tree_cons (name, value, pending_weaks);
344 maybe_apply_pragma_weak (decl)
345 tree decl ATTRIBUTE_UNUSED;
348 #endif /* HANDLE_PRAGMA_WEAK */
350 static GTY(()) tree pending_redefine_extname;
352 #ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
353 static void handle_pragma_redefine_extname PARAMS ((cpp_reader *));
355 /* #pragma redefined_extname oldname newname */
357 handle_pragma_redefine_extname (dummy)
358 cpp_reader *dummy ATTRIBUTE_UNUSED;
360 tree oldname, newname, decl, x;
363 if (c_lex (&oldname) != CPP_NAME)
365 warning ("malformed #pragma redefine_extname, ignored");
368 if (c_lex (&newname) != CPP_NAME)
370 warning ("malformed #pragma redefine_extname, ignored");
375 warning ("junk at end of #pragma redefine_extname");
377 decl = identifier_global_value (oldname);
378 if (decl && TREE_CODE_CLASS (TREE_CODE (decl)) == 'd')
380 if (DECL_ASSEMBLER_NAME_SET_P (decl)
381 && DECL_ASSEMBLER_NAME (decl) != newname)
382 warning ("#pragma redefine_extname conflicts with declaration");
383 SET_DECL_ASSEMBLER_NAME (decl, newname);
386 add_to_renaming_pragma_list(oldname, newname);
391 add_to_renaming_pragma_list (oldname, newname)
392 tree oldname, newname;
394 pending_redefine_extname
395 = tree_cons (oldname, newname, pending_redefine_extname);
398 static GTY(()) tree pragma_extern_prefix;
400 #ifdef HANDLE_PRAGMA_EXTERN_PREFIX
401 static void handle_pragma_extern_prefix PARAMS ((cpp_reader *));
403 /* #pragma extern_prefix "prefix" */
405 handle_pragma_extern_prefix (dummy)
406 cpp_reader *dummy ATTRIBUTE_UNUSED;
411 if (c_lex (&prefix) != CPP_STRING)
413 warning ("malformed #pragma extern_prefix, ignored");
418 warning ("junk at end of #pragma extern_prefix");
420 /* Note that the length includes the null terminator. */
421 pragma_extern_prefix = (TREE_STRING_LENGTH (prefix) > 1 ? prefix : NULL);
425 /* Hook from the front ends to apply the results of one of the preceeding
426 pragmas that rename variables. */
429 maybe_apply_renaming_pragma (decl, asmname)
434 /* Copied from the check in set_decl_assembler_name. */
435 if (TREE_CODE (decl) == FUNCTION_DECL
436 || (TREE_CODE (decl) == VAR_DECL
437 && (TREE_STATIC (decl)
438 || DECL_EXTERNAL (decl)
439 || TREE_PUBLIC (decl))))
440 oldname = DECL_ASSEMBLER_NAME (decl);
444 /* If the name begins with a *, that's a sign of an asmname attached to
445 a previous declaration. */
446 if (IDENTIFIER_POINTER (oldname)[0] == '*')
448 const char *oldasmname = IDENTIFIER_POINTER (oldname) + 1;
449 if (asmname && strcmp (TREE_STRING_POINTER (asmname), oldasmname) != 0)
450 warning ("asm declaration conficts with previous rename");
451 asmname = build_string (strlen (oldasmname), oldasmname);
457 for (p = &pending_redefine_extname; (t = *p) ; p = &TREE_CHAIN (t))
458 if (oldname == TREE_PURPOSE (t))
460 const char *newname = IDENTIFIER_POINTER (TREE_VALUE (t));
462 if (asmname && strcmp (TREE_STRING_POINTER (asmname), newname) != 0)
463 warning ("#pragma redefine_extname conflicts with declaration");
466 return build_string (strlen (newname), newname);
470 #ifdef HANDLE_PRAGMA_EXTERN_PREFIX
471 if (pragma_extern_prefix && !asmname)
473 char *x = concat (TREE_STRING_POINTER (pragma_extern_prefix),
474 IDENTIFIER_POINTER (oldname), NULL);
475 asmname = build_string (strlen (x), x);
487 #ifdef HANDLE_PRAGMA_PACK
488 cpp_register_pragma (parse_in, 0, "pack", handle_pragma_pack);
490 #ifdef HANDLE_PRAGMA_WEAK
491 cpp_register_pragma (parse_in, 0, "weak", handle_pragma_weak);
493 #ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
494 cpp_register_pragma (parse_in, 0, "redefine_extname",
495 handle_pragma_redefine_extname);
497 #ifdef HANDLE_PRAGMA_EXTERN_PREFIX
498 cpp_register_pragma (parse_in, 0, "extern_prefix",
499 handle_pragma_extern_prefix);
502 #ifdef REGISTER_TARGET_PRAGMAS
503 REGISTER_TARGET_PRAGMAS (parse_in);
507 #include "gt-c-pragma.h"