NASM 2.08rc2
[nasm/sigaren-mirror.git] / labels.c
blob9152552e46260f408777107c8035f425ad990ed3
1 /* ----------------------------------------------------------------------- *
2 *
3 * Copyright 1996-2009 The NASM Authors - All Rights Reserved
4 * See the file AUTHORS included with the NASM distribution for
5 * the specific copyright holders.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following
9 * conditions are met:
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following
15 * disclaimer in the documentation and/or other materials provided
16 * with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
19 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
20 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
29 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
30 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * ----------------------------------------------------------------------- */
35 * labels.c label handling for the Netwide Assembler
38 #include "compiler.h"
40 #include <stdio.h>
41 #include <string.h>
42 #include <stdlib.h>
43 #include <inttypes.h>
45 #include "nasm.h"
46 #include "nasmlib.h"
47 #include "hashtbl.h"
50 * A local label is one that begins with exactly one period. Things
51 * that begin with _two_ periods are NASM-specific things.
53 * If TASM compatibility is enabled, a local label can also begin with
54 * @@, so @@local is a TASM compatible local label. Note that we only
55 * check for the first @ symbol, although TASM requires both.
57 #define islocal(l) \
58 (tasm_compatible_mode ? \
59 (((l)[0] == '.' || (l)[0] == '@') && (l)[1] != '.') : \
60 ((l)[0] == '.' && (l)[1] != '.'))
61 #define islocalchar(c) \
62 (tasm_compatible_mode ? \
63 ((c) == '.' || (c) == '@') : \
64 ((c) == '.'))
66 #define LABEL_BLOCK 128 /* no. of labels/block */
67 #define LBLK_SIZE (LABEL_BLOCK*sizeof(union label))
69 #define END_LIST -3 /* don't clash with NO_SEG! */
70 #define END_BLOCK -2
71 #define BOGUS_VALUE -4
73 #define PERMTS_SIZE 16384 /* size of text blocks */
74 #if (PERMTS_SIZE < IDLEN_MAX)
75 #error "IPERMTS_SIZE must be greater than or equal to IDLEN_MAX"
76 #endif
78 /* values for label.defn.is_global */
79 #define DEFINED_BIT 1
80 #define GLOBAL_BIT 2
81 #define EXTERN_BIT 4
82 #define COMMON_BIT 8
84 #define NOT_DEFINED_YET 0
85 #define TYPE_MASK 3
86 #define LOCAL_SYMBOL (DEFINED_BIT)
87 #define GLOBAL_PLACEHOLDER (GLOBAL_BIT)
88 #define GLOBAL_SYMBOL (DEFINED_BIT|GLOBAL_BIT)
90 union label { /* actual label structures */
91 struct {
92 int32_t segment;
93 int64_t offset;
94 char *label, *special;
95 int is_global, is_norm;
96 } defn;
97 struct {
98 int32_t movingon;
99 int64_t dummy;
100 union label *next;
101 } admin;
104 struct permts { /* permanent text storage */
105 struct permts *next; /* for the linked list */
106 int size, usage; /* size and used space in ... */
107 char data[PERMTS_SIZE]; /* ... the data block itself */
110 extern int64_t global_offset_changed; /* defined in nasm.c */
112 static struct hash_table ltab; /* labels hash table */
113 static union label *ldata; /* all label data blocks */
114 static union label *lfree; /* labels free block */
115 static struct permts *perm_head; /* start of perm. text storage */
116 static struct permts *perm_tail; /* end of perm. text storage */
118 static void init_block(union label *blk);
119 static char *perm_copy(const char *string);
121 static char *prevlabel;
123 static bool initialized = false;
125 char lprefix[PREFIX_MAX] = { 0 };
126 char lpostfix[PREFIX_MAX] = { 0 };
129 * Internal routine: finds the `union label' corresponding to the
130 * given label name. Creates a new one, if it isn't found, and if
131 * `create' is true.
133 static union label *find_label(char *label, int create)
135 char *prev;
136 int prevlen, len;
137 union label *lptr, **lpp;
138 char label_str[IDLEN_MAX];
139 struct hash_insert ip;
141 if (islocal(label)) {
142 prev = prevlabel;
143 prevlen = strlen(prev);
144 len = strlen(label);
145 if (prevlen+len >= IDLEN_MAX)
146 return NULL; /* Error... */
147 memcpy(label_str, prev, prevlen);
148 memcpy(label_str+prevlen, label, len+1);
149 label = label_str;
150 } else {
151 prev = "";
152 prevlen = 0;
155 lpp = (union label **) hash_find(&ltab, label, &ip);
156 lptr = lpp ? *lpp : NULL;
158 if (lptr || !create)
159 return lptr;
161 /* Create a new label... */
162 if (lfree->admin.movingon == END_BLOCK) {
164 * must allocate a new block
166 lfree->admin.next =
167 (union label *)nasm_malloc(LBLK_SIZE);
168 lfree = lfree->admin.next;
169 init_block(lfree);
172 lfree->admin.movingon = BOGUS_VALUE;
173 lfree->defn.label = perm_copy(label);
174 lfree->defn.special = NULL;
175 lfree->defn.is_global = NOT_DEFINED_YET;
177 hash_add(&ip, lfree->defn.label, lfree);
178 return lfree++;
181 bool lookup_label(char *label, int32_t *segment, int64_t *offset)
183 union label *lptr;
185 if (!initialized)
186 return false;
188 lptr = find_label(label, 0);
189 if (lptr && (lptr->defn.is_global & DEFINED_BIT)) {
190 *segment = lptr->defn.segment;
191 *offset = lptr->defn.offset;
192 return true;
193 } else
194 return false;
197 bool is_extern(char *label)
199 union label *lptr;
201 if (!initialized)
202 return false;
204 lptr = find_label(label, 0);
205 return (lptr && (lptr->defn.is_global & EXTERN_BIT));
208 void redefine_label(char *label, int32_t segment, int64_t offset, char *special,
209 bool is_norm, bool isextrn)
211 union label *lptr;
212 int exi;
214 /* This routine possibly ought to check for phase errors. Most assemblers
215 * check for phase errors at this point. I don't know whether phase errors
216 * are even possible, nor whether they are checked somewhere else
219 (void)special; /* Don't warn that this parameter is unused */
220 (void)is_norm; /* Don't warn that this parameter is unused */
221 (void)isextrn; /* Don't warn that this parameter is unused */
223 #ifdef DEBUG
224 #if DEBUG<3
225 if (!strncmp(label, "debugdump", 9))
226 #endif
227 nasm_error(ERR_DEBUG, "redefine_label (%s, %"PRIx32", %"PRIx64", %s, %d, %d)",
228 label, segment, offset, special, is_norm, isextrn);
229 #endif
231 lptr = find_label(label, 1);
232 if (!lptr)
233 nasm_error(ERR_PANIC, "can't find label `%s' on pass two", label);
235 if (!islocal(label)) {
236 if (!islocalchar(*label) && lptr->defn.is_norm)
237 prevlabel = lptr->defn.label;
240 if (lptr->defn.offset != offset)
241 global_offset_changed++;
243 lptr->defn.offset = offset;
244 lptr->defn.segment = segment;
246 if (pass0 == 1) {
247 exi = !!(lptr->defn.is_global & GLOBAL_BIT);
248 if (exi) {
249 char *xsymbol;
250 int slen;
251 slen = strlen(lprefix);
252 slen += strlen(lptr->defn.label);
253 slen += strlen(lpostfix);
254 slen++; /* room for that null char */
255 xsymbol = nasm_malloc(slen);
256 snprintf(xsymbol, slen, "%s%s%s", lprefix, lptr->defn.label,
257 lpostfix);
259 ofmt->symdef(xsymbol, segment, offset, exi,
260 special ? special : lptr->defn.special);
261 ofmt->current_dfmt->debug_deflabel(xsymbol, segment, offset,
262 exi,
263 special ? special : lptr->
264 defn.special);
265 /** nasm_free(xsymbol); ! outobj.c stores the pointer; ouch!!! **/
266 } else {
267 if ((lptr->defn.is_global & (GLOBAL_BIT | EXTERN_BIT)) !=
268 EXTERN_BIT) {
269 ofmt->symdef(lptr->defn.label, segment, offset, exi,
270 special ? special : lptr->defn.special);
271 ofmt->current_dfmt->debug_deflabel(label, segment, offset,
272 exi,
273 special ? special :
274 lptr->defn.special);
278 /* if (pass0 == 1) */
281 void define_label(char *label, int32_t segment, int64_t offset, char *special,
282 bool is_norm, bool isextrn)
284 union label *lptr;
285 int exi;
287 #ifdef DEBUG
288 #if DEBUG<3
289 if (!strncmp(label, "debugdump", 9))
290 #endif
291 nasm_error(ERR_DEBUG, "define_label (%s, %"PRIx32", %"PRIx64", %s, %d, %d)",
292 label, segment, offset, special, is_norm, isextrn);
293 #endif
294 lptr = find_label(label, 1);
295 if (lptr->defn.is_global & DEFINED_BIT) {
296 nasm_error(ERR_NONFATAL, "symbol `%s' redefined", label);
297 return;
299 lptr->defn.is_global |= DEFINED_BIT;
300 if (isextrn)
301 lptr->defn.is_global |= EXTERN_BIT;
303 if (!islocalchar(label[0]) && is_norm) {
304 /* not local, but not special either */
305 prevlabel = lptr->defn.label;
306 } else if (islocal(label) && !*prevlabel) {
307 nasm_error(ERR_NONFATAL, "attempt to define a local label before any"
308 " non-local labels");
311 lptr->defn.segment = segment;
312 lptr->defn.offset = offset;
313 lptr->defn.is_norm = (!islocalchar(label[0]) && is_norm);
315 if (pass0 == 1 || (!is_norm && !isextrn && (segment > 0) && (segment & 1))) {
316 exi = !!(lptr->defn.is_global & GLOBAL_BIT);
317 if (exi) {
318 char *xsymbol;
319 int slen;
320 slen = strlen(lprefix);
321 slen += strlen(lptr->defn.label);
322 slen += strlen(lpostfix);
323 slen++; /* room for that null char */
324 xsymbol = nasm_malloc(slen);
325 snprintf(xsymbol, slen, "%s%s%s", lprefix, lptr->defn.label,
326 lpostfix);
328 ofmt->symdef(xsymbol, segment, offset, exi,
329 special ? special : lptr->defn.special);
330 ofmt->current_dfmt->debug_deflabel(xsymbol, segment, offset,
331 exi,
332 special ? special : lptr->
333 defn.special);
334 /** nasm_free(xsymbol); ! outobj.c stores the pointer; ouch!!! **/
335 } else {
336 if ((lptr->defn.is_global & (GLOBAL_BIT | EXTERN_BIT)) !=
337 EXTERN_BIT) {
338 ofmt->symdef(lptr->defn.label, segment, offset, exi,
339 special ? special : lptr->defn.special);
340 ofmt->current_dfmt->debug_deflabel(label, segment, offset,
341 exi,
342 special ? special :
343 lptr->defn.special);
346 } /* if (pass0 == 1) */
349 void define_common(char *label, int32_t segment, int32_t size, char *special)
351 union label *lptr;
353 lptr = find_label(label, 1);
354 if ((lptr->defn.is_global & DEFINED_BIT) &&
355 (passn == 1 || !(lptr->defn.is_global & COMMON_BIT))) {
356 nasm_error(ERR_NONFATAL, "symbol `%s' redefined", label);
357 return;
359 lptr->defn.is_global |= DEFINED_BIT|COMMON_BIT;
361 if (!islocalchar(label[0])) {
362 prevlabel = lptr->defn.label;
363 } else {
364 nasm_error(ERR_NONFATAL, "attempt to define a local label as a "
365 "common variable");
366 return;
369 lptr->defn.segment = segment;
370 lptr->defn.offset = 0;
372 if (pass0 == 0)
373 return;
375 ofmt->symdef(lptr->defn.label, segment, size, 2,
376 special ? special : lptr->defn.special);
377 ofmt->current_dfmt->debug_deflabel(lptr->defn.label, segment, size, 2,
378 special ? special : lptr->defn.
379 special);
382 void declare_as_global(char *label, char *special)
384 union label *lptr;
386 if (islocal(label)) {
387 nasm_error(ERR_NONFATAL, "attempt to declare local symbol `%s' as"
388 " global", label);
389 return;
391 lptr = find_label(label, 1);
392 switch (lptr->defn.is_global & TYPE_MASK) {
393 case NOT_DEFINED_YET:
394 lptr->defn.is_global = GLOBAL_PLACEHOLDER;
395 lptr->defn.special = special ? perm_copy(special) : NULL;
396 break;
397 case GLOBAL_PLACEHOLDER: /* already done: silently ignore */
398 case GLOBAL_SYMBOL:
399 break;
400 case LOCAL_SYMBOL:
401 if (!(lptr->defn.is_global & EXTERN_BIT)) {
402 nasm_error(ERR_WARNING, "symbol `%s': GLOBAL directive "
403 "after symbol definition is an experimental feature", label);
404 lptr->defn.is_global = GLOBAL_SYMBOL;
406 break;
410 int init_labels(void)
412 hash_init(&ltab, HASH_LARGE);
414 ldata = lfree = (union label *)nasm_malloc(LBLK_SIZE);
415 init_block(lfree);
417 perm_head =
418 perm_tail = (struct permts *)nasm_malloc(sizeof(struct permts));
420 perm_head->next = NULL;
421 perm_head->size = PERMTS_SIZE;
422 perm_head->usage = 0;
424 prevlabel = "";
426 initialized = true;
428 return 0;
431 void cleanup_labels(void)
433 union label *lptr, *lhold;
435 initialized = false;
437 hash_free(&ltab);
439 lptr = lhold = ldata;
440 while (lptr) {
441 lptr = &lptr[LABEL_BLOCK-1];
442 lptr = lptr->admin.next;
443 nasm_free(lhold);
444 lhold = lptr;
447 while (perm_head) {
448 perm_tail = perm_head;
449 perm_head = perm_head->next;
450 nasm_free(perm_tail);
454 static void init_block(union label *blk)
456 int j;
458 for (j = 0; j < LABEL_BLOCK - 1; j++)
459 blk[j].admin.movingon = END_LIST;
460 blk[LABEL_BLOCK - 1].admin.movingon = END_BLOCK;
461 blk[LABEL_BLOCK - 1].admin.next = NULL;
464 static char *perm_copy(const char *string)
466 char *p;
467 int len = strlen(string)+1;
469 nasm_assert(len <= PERMTS_SIZE);
471 if (perm_tail->size - perm_tail->usage < len) {
472 perm_tail->next =
473 (struct permts *)nasm_malloc(sizeof(struct permts));
474 perm_tail = perm_tail->next;
475 perm_tail->next = NULL;
476 perm_tail->size = PERMTS_SIZE;
477 perm_tail->usage = 0;
479 p = perm_tail->data + perm_tail->usage;
480 memcpy(p, string, len);
481 perm_tail->usage += len;
483 return p;
486 char *local_scope(char *label)
488 return islocal(label) ? prevlabel : "";
492 * Notes regarding bug involving redefinition of external segments.
494 * Up to and including v0.97, the following code didn't work. From 0.97
495 * developers release 2 onwards, it will generate an error.
497 * EXTERN extlabel
498 * newlabel EQU extlabel + 1
500 * The results of allowing this code through are that two import records
501 * are generated, one for 'extlabel' and one for 'newlabel'.
503 * The reason for this is an inadequacy in the defined interface between
504 * the label manager and the output formats. The problem lies in how the
505 * output format driver tells that a label is an external label for which
506 * a label import record must be produced. Most (all except bin?) produce
507 * the record if the segment number of the label is not one of the internal
508 * segments that the output driver is producing.
510 * A simple fix to this would be to make the output formats keep track of
511 * which symbols they've produced import records for, and make them not
512 * produce import records for segments that are already defined.
514 * The best way, which is slightly harder but reduces duplication of code
515 * and should therefore make the entire system smaller and more stable is
516 * to change the interface between assembler, define_label(), and
517 * the output module. The changes that are needed are:
519 * The semantics of the 'isextern' flag passed to define_label() need
520 * examining. This information may or may not tell us what we need to
521 * know (ie should we be generating an import record at this point for this
522 * label). If these aren't the semantics, the semantics should be changed
523 * to this.
525 * The output module interface needs changing, so that the `isextern' flag
526 * is passed to the module, so that it can be easily tested for.