1 /* symbols.c -symbol table-
3 Copyright (C) 1987, 1990, 1991, 1992 Free Software Foundation, Inc.
5 This file is part of GAS, the GNU Assembler.
7 GAS is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GAS is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GAS; see the file COPYING. If not, write to
19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
22 static char rcsid[] = "$FreeBSD$";
27 #include "obstack.h" /* For "symbols.h" */
30 #ifndef WORKING_DOT_WORD
31 extern int new_broken_words;
36 sy_hash; /* symbol-name => struct symbol pointer */
38 /* Below are commented in "symbols.h". */
39 unsigned int local_bss_counter;
40 symbolS * symbol_rootP;
41 symbolS * symbol_lastP;
44 symbolS* dot_text_symbol;
45 symbolS* dot_data_symbol;
46 symbolS* dot_bss_symbol;
51 * Un*x idea of local labels. They are made by "n:" where n
52 * is any decimal digit. Refer to them with
53 * "nb" for previous (backward) n:
54 * or "nf" for next (forward) n:.
56 * Like Un*x AS, we have one set of local label counters for entire assembly,
57 * not one set per (sub)segment like in most assemblers. This implies that
58 * one can refer to a label in another segment, and indeed some crufty
59 * compilers have done just that.
61 * I document the symbol names here to save duplicating words elsewhere.
62 * The mth occurence of label n: is turned into the symbol "Ln^Am" where
63 * n is a digit and m is a decimal number. "L" makes it a label discarded
64 * unless debugging and "^A"('\1') ensures no ordinary symbol SHOULD get the
65 * same name as a local label symbol. The first "4:" is "L4^A1" - the m
69 typedef short unsigned int
72 static local_label_countT
73 local_label_counter[10];
75 static /* Returned to caller, then copied. */
76 char symbol_name_build[12]; /* used for created names ("4f") */
78 #ifdef LOCAL_LABELS_DOLLAR
79 int local_label_defined[10];
87 symbol_rootP = NULL; /* In case we have 0 symbols (!!) */
89 memset((char *)(& abs_symbol), '\0', sizeof(abs_symbol));
90 S_SET_SEGMENT(&abs_symbol, SEG_ABSOLUTE); /* Can't initialise a union. Sigh. */
91 memset((char *)(local_label_counter), '\0', sizeof(local_label_counter) );
92 local_bss_counter = 0;
98 * Caller must copy returned name: we re-use the area for the next name.
101 char * /* Return local label name. */
102 local_label_name(n, augend)
103 register int n; /* we just saw "n:", "nf" or "nb" : n a digit */
104 register int augend; /* 0 for nb, 1 for n:, nf */
108 char symbol_name_temporary[10]; /* build up a number, BACKWARDS */
111 know( augend == 0 || augend == 1 );
112 p = symbol_name_build;
115 * p ++ = n + '0'; /* Make into ASCII */
116 n = local_label_counter[ n ] + augend;
117 /* version number of this local label */
119 * Next code just does sprintf( {}, "%d", n);
120 * It is more elegant to do the next part recursively, but a procedure
121 * call for each digit emitted is considered too costly.
123 q = symbol_name_temporary;
124 for (*q++=0; n; q++) /* emits NOTHING if n starts as 0 */
126 know(n>0); /* We expect n > 0 always */
130 while (( * p ++ = * -- q ) != '\0') ;;
132 /* The label, as a '\0' ended string, starts at symbol_name_build. */
133 return(symbol_name_build);
134 } /* local_label_name() */
138 int n; /* just saw "n:" */
140 local_label_counter[n] ++;
141 #ifdef LOCAL_LABELS_DOLLAR
142 local_label_defined[n]=1;
144 colon (local_label_name (n, 0));
150 * Return a pointer to a new symbol.
151 * Die if we can't make a new symbol.
152 * Fill in the symbol's values.
153 * Add symbol to end of symbol chain.
156 * Please always call this to create a new symbol.
158 * Changes since 1985: Symbol names may not contain '\0'. Sigh.
159 * 2nd argument is now a SEG rather than a TYPE. The mapping between
160 * segments and types is mostly encapsulated herein (actually, we inherit it
161 * from macros in struc-symbol.h).
164 symbolS *symbol_new(name, segment, value, frag)
165 char *name; /* It is copied, the caller can destroy/modify */
166 segT segment; /* Segment identifier (SEG_<something>) */
167 long value; /* Symbol value */
168 fragS *frag; /* Associated fragment */
170 unsigned int name_length;
171 char *preserved_copy_of_name;
174 name_length = strlen(name) + 1; /* +1 for \0 */
175 obstack_grow(¬es, name, name_length);
176 preserved_copy_of_name = obstack_finish(¬es);
177 symbolP = (symbolS *) obstack_alloc(¬es, sizeof(symbolS));
179 /* symbol must be born in some fixed state. This seems as good as any. */
180 memset(symbolP, 0, sizeof(symbolS));
182 #ifdef STRIP_UNDERSCORE
183 S_SET_NAME(symbolP, (*preserved_copy_of_name == '_'
184 ? preserved_copy_of_name + 1
185 : preserved_copy_of_name));
186 #else /* STRIP_UNDERSCORE */
187 S_SET_NAME(symbolP, preserved_copy_of_name);
188 #endif /* STRIP_UNDERSCORE */
190 S_SET_SEGMENT(symbolP, segment);
191 S_SET_VALUE(symbolP, value);
192 /* symbol_clear_list_pointers(symbolP); uneeded if symbol is born zeroed. */
194 symbolP->sy_frag = frag;
195 /* krm: uneeded if symbol is born zeroed.
196 symbolP->sy_forward = NULL; */ /* JF */
197 symbolP->sy_number = ~0;
198 symbolP->sy_name_offset = ~0;
201 * Link to end of symbol chain.
203 symbol_append(symbolP, symbol_lastP, &symbol_rootP, &symbol_lastP);
205 obj_symbol_new_hook(symbolP);
208 /* verify_symbol_chain(symbol_rootP, symbol_lastP); */
218 * We have just seen "<name>:".
219 * Creates a struct symbol unless it already exists.
221 * Gripes if we are redefining a symbol incompatibly (and ignores it).
224 void colon(sym_name) /* just seen "x:" - rattle symbols & frags */
225 register char * sym_name; /* symbol name, as a cannonical string */
226 /* We copy this string: OK to alter later. */
228 register symbolS * symbolP; /* symbol we are working with */
230 #ifdef LOCAL_LABELS_DOLLAR
231 /* Sun local labels go out of scope whenever a non-local symbol is defined. */
233 if (*sym_name != 'L')
234 memset((void *) local_label_defined, '\0', sizeof(local_label_defined));
237 #ifndef WORKING_DOT_WORD
238 if (new_broken_words) {
239 struct broken_word *a;
244 extern const md_short_jump_size;
245 extern const md_long_jump_size;
246 possible_bytes=md_short_jump_size + new_broken_words * md_long_jump_size;
249 frag_opcode=frag_var(rs_broken_word,
253 (symbolS *) broken_words,
257 /* We want to store the pointer to where to insert the jump table in the
258 fr_opcode of the rs_broken_word frag. This requires a little hackery */
259 while (frag_tmp && (frag_tmp->fr_type != rs_broken_word || frag_tmp->fr_opcode))
260 frag_tmp=frag_tmp->fr_next;
262 frag_tmp->fr_opcode=frag_opcode;
263 new_broken_words = 0;
265 for (a=broken_words;a && a->dispfrag == 0;a=a->next_broken_word)
266 a->dispfrag=frag_tmp;
269 if ((symbolP = symbol_find(sym_name)) != 0) {
272 * If the new symbol is .comm AND it has a size of zero,
273 * we ignore it (i.e. the old symbol overrides it)
275 if ((SEGMENT_TO_SYMBOL_TYPE((int) now_seg) == (N_UNDF | N_EXT)) &&
276 ((obstack_next_free(& frags) - frag_now->fr_literal) == 0))
279 * If the old symbol is .comm and it has a size of zero,
280 * we override it with the new symbol value.
282 if (S_IS_EXTERNAL(symbolP) && S_IS_DEFINED(symbolP)
283 && (S_GET_VALUE(symbolP) == 0)) {
284 symbolP->sy_frag = frag_now;
285 S_GET_OTHER(symbolP) = const_flag;
286 S_SET_VALUE(symbolP, obstack_next_free(& frags) - frag_now->fr_literal);
287 symbolP->sy_symbol.n_type |=
288 SEGMENT_TO_SYMBOL_TYPE((int) now_seg); /* keep N_EXT bit */
293 * Now check for undefined symbols
295 if (!S_IS_DEFINED(symbolP)) {
296 if (S_GET_VALUE(symbolP) == 0) {
297 symbolP->sy_frag = frag_now;
299 S_GET_OTHER(symbolP) = const_flag;
301 S_SET_VALUE(symbolP, obstack_next_free(&frags) - frag_now->fr_literal);
302 S_SET_SEGMENT(symbolP, now_seg);
305 #endif /* if we have one, it better be zero. */
309 * There are still several cases to check:
310 * A .comm/.lcomm symbol being redefined as
311 * initialized data is OK
312 * A .comm/.lcomm symbol being redefined with
313 * a larger size is also OK
315 * This only used to be allowed on VMS gas, but Sun cc
316 * on the sparc also depends on it.
318 /* char New_Type = SEGMENT_TO_SYMBOL_TYPE((int) now_seg); */
320 if (((!S_IS_DEBUG(symbolP) && !S_IS_DEFINED(symbolP) && S_IS_EXTERNAL(symbolP))
321 || (S_GET_SEGMENT(symbolP) == SEG_BSS))
322 && ((now_seg == SEG_DATA)
323 || (now_seg == S_GET_SEGMENT(symbolP)))) {
325 * Select which of the 2 cases this is
327 if (now_seg != SEG_DATA) {
329 * New .comm for prev .comm symbol.
330 * If the new size is larger we just
331 * change its value. If the new size
332 * is smaller, we ignore this symbol
334 if (S_GET_VALUE(symbolP)
335 < ((unsigned) (obstack_next_free(& frags) - frag_now->fr_literal))) {
337 obstack_next_free(& frags) -
338 frag_now->fr_literal);
342 * It is a .comm/.lcomm being converted
343 * to initialized data.
345 symbolP->sy_frag = frag_now;
347 S_GET_OTHER(symbolP) = const_flag;
349 S_SET_VALUE(symbolP, obstack_next_free(& frags) - frag_now->fr_literal);
350 S_SET_SEGMENT(symbolP, now_seg); /* keep N_EXT bit */
354 as_fatal("Symbol \"%s\" is already defined as \"%s\"/%d.",
356 segment_name(S_GET_SEGMENT(symbolP)),
357 S_GET_VALUE(symbolP));
359 as_fatal("Symbol \"%s\" is already defined as \"%s\"/%d.%d.%d.",
361 segment_name(S_GET_SEGMENT(symbolP)),
362 S_GET_OTHER(symbolP), S_GET_DESC(symbolP),
363 S_GET_VALUE(symbolP));
364 #endif /* OBJ_COFF */
366 } /* if the undefined symbol has no value */
369 /* Don't blow up if the definition is the same */
370 if (!(frag_now == symbolP->sy_frag
371 && S_GET_VALUE(symbolP) == obstack_next_free(&frags) - frag_now->fr_literal
372 && S_GET_SEGMENT(symbolP) == now_seg) )
373 as_fatal("Symbol %s already defined.", sym_name);
374 } /* if this symbol is not yet defined */
377 symbolP = symbol_new(sym_name,
379 (valueT)(obstack_next_free(&frags)-frag_now->fr_literal),
382 S_SET_OTHER(symbolP, const_flag);
385 symbol_table_insert(symbolP);
386 } /* if we have seen this symbol before */
393 * symbol_table_insert()
395 * Die if we can't insert the symbol.
399 void symbol_table_insert(symbolP)
402 register char *error_string;
405 know(S_GET_NAME(symbolP));
407 if (*(error_string = hash_jam(sy_hash, S_GET_NAME(symbolP), (char *)symbolP))) {
408 as_fatal("Inserting \"%s\" into symbol table failed: %s",
409 S_GET_NAME(symbolP), error_string);
411 } /* symbol_table_insert() */
414 * symbol_find_or_make()
416 * If a symbol name does not exist, create it as undefined, and insert
417 * it into the symbol table. Return a pointer to it.
419 symbolS *symbol_find_or_make(name)
422 register symbolS *symbolP;
424 symbolP = symbol_find(name);
426 if (symbolP == NULL) {
427 symbolP = symbol_make(name);
429 symbol_table_insert(symbolP);
430 } /* if symbol wasn't found */
433 } /* symbol_find_or_make() */
435 symbolS *symbol_make(name)
440 /* Let the machine description default it, e.g. for register names. */
441 symbolP = md_undefined_symbol(name);
444 symbolP = symbol_new(name,
448 } /* if md didn't build us a symbol */
451 } /* symbol_make() */
456 * Implement symbol table lookup.
457 * In: A symbol's name as a string: '\0' can't be part of a symbol name.
458 * Out: NULL if the name was not in the symbol table, else the address
459 * of a struct symbol associated with that name.
462 symbolS *symbol_find(name)
465 #ifdef STRIP_UNDERSCORE
466 return(symbol_find_base(name, 1));
467 #else /* STRIP_UNDERSCORE */
468 return(symbol_find_base(name, 0));
469 #endif /* STRIP_UNDERSCORE */
470 } /* symbol_find() */
472 symbolS *symbol_find_base(name, strip_underscore)
474 int strip_underscore;
476 if (strip_underscore && *name == '_') name++;
477 return ( (symbolS *) hash_find( sy_hash, name ));
481 * Once upon a time, symbols were kept in a singly linked list. At
482 * least coff needs to be able to rearrange them from time to time, for
483 * which a doubly linked list is much more convenient. Loic did these
484 * as macros which seemed dangerous to me so they're now functions.
488 /* Link symbol ADDME after symbol TARGET in the chain. */
489 void symbol_append(addme, target, rootPP, lastPP)
495 if (target == NULL) {
496 know(*rootPP == NULL);
497 know(*lastPP == NULL);
501 } /* if the list is empty */
503 if (target->sy_next != NULL) {
504 #ifdef SYMBOLS_NEED_BACKPOINTERS
505 target->sy_next->sy_previous = addme;
506 #endif /* SYMBOLS_NEED_BACKPOINTERS */
508 know(*lastPP == target);
510 } /* if we have a next */
512 addme->sy_next = target->sy_next;
513 target->sy_next = addme;
515 #ifdef SYMBOLS_NEED_BACKPOINTERS
516 addme->sy_previous = target;
517 #endif /* SYMBOLS_NEED_BACKPOINTERS */
520 /* verify_symbol_chain(*rootPP, *lastPP); */
524 } /* symbol_append() */
526 #ifdef SYMBOLS_NEED_BACKPOINTERS
527 /* Remove SYMBOLP from the list. */
528 void symbol_remove(symbolP, rootPP, lastPP)
533 if (symbolP == *rootPP) {
534 *rootPP = symbolP->sy_next;
535 } /* if it was the root */
537 if (symbolP == *lastPP) {
538 *lastPP = symbolP->sy_previous;
539 } /* if it was the tail */
541 if (symbolP->sy_next != NULL) {
542 symbolP->sy_next->sy_previous = symbolP->sy_previous;
545 if (symbolP->sy_previous != NULL) {
546 symbolP->sy_previous->sy_next = symbolP->sy_next;
550 verify_symbol_chain(*rootPP, *lastPP);
554 } /* symbol_remove() */
556 /* Set the chain pointers of SYMBOL to null. */
557 void symbol_clear_list_pointers(symbolP)
560 symbolP->sy_next = NULL;
561 symbolP->sy_previous = NULL;
562 } /* symbol_clear_list_pointers() */
564 /* Link symbol ADDME before symbol TARGET in the chain. */
565 void symbol_insert(addme, target, rootPP, lastPP)
571 if (target->sy_previous != NULL) {
572 target->sy_previous->sy_next = addme;
574 know(*rootPP == target);
578 addme->sy_previous = target->sy_previous;
579 target->sy_previous = addme;
580 addme->sy_next = target;
583 verify_symbol_chain(*rootPP, *lastPP);
587 } /* symbol_insert() */
588 #endif /* SYMBOLS_NEED_BACKPOINTERS */
590 void verify_symbol_chain(rootP, lastP)
594 symbolS *symbolP = rootP;
596 if (symbolP == NULL) {
600 for ( ; symbol_next(symbolP) != NULL; symbolP = symbol_next(symbolP)) {
601 #ifdef SYMBOLS_NEED_BACKPOINTERS
602 /*$if (symbolP->sy_previous) {
603 know(symbolP->sy_previous->sy_next == symbolP);
605 know(symbolP == rootP);
606 }$*/ /* both directions */
607 know(symbolP->sy_next->sy_previous == symbolP);
608 #else /* SYMBOLS_NEED_BACKPOINTERS */
610 #endif /* SYMBOLS_NEED_BACKPOINTERS */
611 } /* verify pointers */
613 know(lastP == symbolP);
616 } /* verify_symbol_chain() */
620 * decode name that may have been generated by local_label_name() above. If
621 * the name wasn't generated by local_label_name(), then return it unaltered.
622 * This is used for error messages.
625 char *decode_local_label_name(s)
630 /* int label_version; */
631 char *message_format = "\"%d\" (instance number %s of a local label)";
636 } /* not a local_label_name() generated name. */
638 label_number = s[1] - '0';
640 (void) sprintf(symbol_decode = obstack_alloc(¬es, strlen(s + 3) + strlen(message_format) + 10),
641 message_format, label_number, s + 3);
643 return(symbol_decode);
644 } /* decode_local_label_name() */
654 /* end of symbols.c */