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Prepare for migration to hg
author lost
date Fri, 19 Mar 2010 02:54:14 +0000
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338:e7885b3ee266 339:eb230fa7d28e
1 /*
2 link.c
3 Copyright © 2009 William Astle
4
5 This file is part of LWLINK.
6
7 LWLINK is free software: you can redistribute it and/or modify it under the
8 terms of the GNU General Public License as published by the Free Software
9 Foundation, either version 3 of the License, or (at your option) any later
10 version.
11
12 This program is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 more details.
16
17 You should have received a copy of the GNU General Public License along with
18 this program. If not, see <http://www.gnu.org/licenses/>.
19
20
21 Resolve section and symbol addresses; handle incomplete references
22 */
23
24 #include <config.h>
25
26 #include <stdio.h>
27 #include <stdlib.h>
28
29 #include "expr.h"
30 #include "lwlink.h"
31 #include "util.h"
32
33 struct section_list *sectlist = NULL;
34 int nsects = 0;
35 static int nforced = 0;
36
37 void check_section_name(char *name, int *base, fileinfo_t *fn)
38 {
39 int sn;
40
41 if (fn -> forced == 0)
42 return;
43
44 for (sn = 0; sn < fn -> nsections; sn++)
45 {
46 if (!strcmp(name, fn -> sections[sn].name))
47 {
48 // we have a match
49 sectlist = lw_realloc(sectlist, sizeof(struct section_list) * (nsects + 1));
50 sectlist[nsects].ptr = &(fn -> sections[sn]);
51
52 fn -> sections[sn].processed = 1;
53 fn -> sections[sn].loadaddress = *base;
54 *base += fn -> sections[sn].codesize;
55 nsects++;
56 }
57 }
58 for (sn = 0; sn < fn -> nsubs; sn++)
59 {
60 check_section_name(name, base, fn -> subs[sn]);
61 }
62 }
63
64 void add_matching_sections(char *name, int yesflags, int noflags, int *base);
65 void check_section_flags(int yesflags, int noflags, int *base, fileinfo_t *fn)
66 {
67 int sn;
68
69 if (fn -> forced == 0)
70 return;
71
72 for (sn = 0; sn < fn -> nsections; sn++)
73 {
74 // ignore if the noflags tell us to
75 if (noflags && (fn -> sections[sn].flags & noflags))
76 continue;
77 // ignore unless the yesflags tell us not to
78 if (yesflags && (fn -> sections[sn].flags & yesflags == 0))
79 continue;
80 // ignore it if already processed
81 if (fn -> sections[sn].processed)
82 continue;
83
84 // we have a match - now collect *all* sections of the same name!
85 add_matching_sections(fn -> sections[sn].name, 0, 0, base);
86
87 // and then continue looking for sections
88 }
89 for (sn = 0; sn < fn -> nsubs; sn++)
90 {
91 check_section_flags(yesflags, noflags, base, fn -> subs[sn]);
92 }
93 }
94
95
96
97 void add_matching_sections(char *name, int yesflags, int noflags, int *base)
98 {
99 int fn;
100 if (name)
101 {
102 // named section
103 // look for all instances of a section by the specified name
104 // and resolve base addresses and add to the list
105 for (fn = 0; fn < ninputfiles; fn++)
106 {
107 check_section_name(name, base, inputfiles[fn]);
108 }
109 }
110 else
111 {
112 // wildcard section
113 // named section
114 // look for all instances of a section by the specified name
115 // and resolve base addresses and add to the list
116 for (fn = 0; fn < ninputfiles; fn++)
117 {
118 check_section_flags(yesflags, noflags, base, inputfiles[fn]);
119 }
120 }
121 }
122
123 // work out section load order and resolve base addresses for each section
124 // make a list of sections to load in order
125 void resolve_sections(void)
126 {
127 int laddr = 0;
128 int ln, sn, fn;
129
130 for (ln = 0; ln < linkscript.nlines; ln++)
131 {
132 if (linkscript.lines[ln].loadat >= 0)
133 laddr = linkscript.lines[ln].loadat;
134 add_matching_sections(linkscript.lines[ln].sectname, linkscript.lines[ln].yesflags, linkscript.lines[ln].noflags, &laddr);
135
136 if (linkscript.lines[ln].sectname)
137 {
138 }
139 else
140 {
141 // wildcard section
142 // look for all sections not yet processed that match flags
143
144 int f = 0;
145 int fn0, sn0;
146 char *sname;
147
148 // named section
149 // look for all instances of a section by the specified name
150 // and resolve base addresses and add to the list
151 for (fn0 = 0; fn0 < ninputfiles; fn0++)
152 {
153 for (sn0 = 0; sn0 < inputfiles[fn0] -> nsections; sn0++)
154 {
155 // ignore if the "no flags" bit says to
156 if (linkscript.lines[ln].noflags && (inputfiles[fn0] -> sections[sn0].flags & linkscript.lines[ln].noflags))
157 continue;
158 // ignore unless the yes flags tell us not to
159 if (linkscript.lines[ln].yesflags && (inputfiles[fn0] -> sections[sn0].flags & linkscript.lines[ln].yesflags == 0))
160 continue;
161 if (inputfiles[fn0] -> sections[sn0].processed == 0)
162 {
163 sname = inputfiles[fn0] -> sections[sn0].name;
164 for (fn = 0; fn < ninputfiles; fn++)
165 {
166 for (sn = 0; sn < inputfiles[fn] -> nsections; sn++)
167 {
168 if (!strcmp(sname, inputfiles[fn] -> sections[sn].name))
169 {
170 // we have a match
171 sectlist = lw_realloc(sectlist, sizeof(struct section_list) * (nsects + 1));
172 sectlist[nsects].ptr = &(inputfiles[fn] -> sections[sn]);
173
174 inputfiles[fn] -> sections[sn].processed = 1;
175 if (!f && linkscript.lines[ln].loadat >= 0)
176 {
177 f = 1;
178 sectlist[nsects].forceaddr = 1;
179 laddr = linkscript.lines[ln].loadat;
180 }
181 else
182 {
183 sectlist[nsects].forceaddr = 0;
184 }
185 inputfiles[fn] -> sections[sn].loadaddress = laddr;
186 laddr += inputfiles[fn] -> sections[sn].codesize;
187 nsects++;
188 }
189 }
190 }
191 }
192 }
193 }
194 }
195 }
196
197 // theoretically, all the base addresses are set now
198 }
199
200 lw_expr_stack_t *find_external_sym_recurse(char *sym, fileinfo_t *fn)
201 {
202 int sn;
203 lw_expr_stack_t *r;
204 lw_expr_term_t *term;
205 symtab_t *se;
206 int val;
207
208 for (sn = 0; sn < fn -> nsections; sn++)
209 {
210 for (se = fn -> sections[sn].exportedsyms; se; se = se -> next)
211 {
212 if (!strcmp(sym, se -> sym))
213 {
214 if (!(fn -> forced))
215 {
216 fn -> forced = 1;
217 nforced = 1;
218 }
219 val = se -> offset + fn -> sections[sn].loadaddress;
220 r = lw_expr_stack_create();
221 term = lw_expr_term_create_int(val & 0xffff);
222 lw_expr_stack_push(r, term);
223 lw_expr_term_free(term);
224 return r;
225 }
226 }
227 }
228
229 for (sn = 0; sn < fn -> nsubs; sn++)
230 {
231 r = find_external_sym_recurse(sym, fn -> subs[sn]);
232 if (r)
233 {
234 if (!(fn -> forced))
235 {
236 nforced = 1;
237 fn -> forced = 1;
238 }
239 return r;
240 }
241 }
242 return NULL;
243 }
244
245 // resolve all incomplete references now
246 // anything that is unresolvable at this stage will throw an error
247 // because we know the load address of every section now
248 lw_expr_stack_t *resolve_sym(char *sym, int symtype, void *state)
249 {
250 section_t *sect = state;
251 lw_expr_term_t *term;
252 int val = 0, i, fn;
253 lw_expr_stack_t *s;
254 symtab_t *se;
255 fileinfo_t *fp;
256
257 if (symtype == 1)
258 {
259 // local symbol
260 if (!sym)
261 {
262 val = sect -> loadaddress;
263 goto out;
264 }
265
266 // start with this section
267 for (se = sect -> localsyms; se; se = se -> next)
268 {
269 if (!strcmp(se -> sym, sym))
270 {
271 val = se -> offset + sect -> loadaddress;
272 goto out;
273 }
274 }
275 // not in this section - check all sections in this file
276 for (i = 0; i < sect -> file -> nsections; i++)
277 {
278 for (se = sect -> file -> sections[i].localsyms; se; se = se -> next)
279 {
280 if (!strcmp(se -> sym, sym))
281 {
282 val = se -> offset + sect -> file -> sections[i].loadaddress;
283 goto out;
284 }
285 }
286 }
287 // not found
288 symerr = 1;
289 fprintf(stderr, "Local symbol %s not found in %s:%s\n", sym, sect -> file -> filename, sect -> name);
290 goto outerr;
291 }
292 else
293 {
294 // external symbol
295 // read all files in order until found (or not found)
296 if (sect)
297 {
298 for (fp = sect -> file; fp; fp = fp -> parent)
299 {
300 s = find_external_sym_recurse(sym, fp);
301 if (s)
302 return s;
303 }
304 }
305
306 for (fn = 0; fn < ninputfiles; fn++)
307 {
308 s = find_external_sym_recurse(sym, inputfiles[fn]);
309 if (s)
310 return s;
311 }
312 if (sect)
313 {
314 fprintf(stderr, "External symbol %s not found in %s:%s\n", sym, sect -> file -> filename, sect -> name);
315 }
316 else
317 {
318 fprintf(stderr, "External symbol %s not found\n", sym);
319 }
320 symerr = 1;
321 goto outerr;
322 }
323 fprintf(stderr, "Shouldn't ever get here!!!\n");
324 exit(88);
325 out:
326 s = lw_expr_stack_create();
327 term = lw_expr_term_create_int(val & 0xffff);
328 lw_expr_stack_push(s, term);
329 lw_expr_term_free(term);
330 return s;
331 outerr:
332 return NULL;
333 }
334
335 void resolve_references(void)
336 {
337 int sn;
338 reloc_t *rl;
339 int rval;
340
341 // resolve entry point if required
342 // this must resolve to an *exported* symbol and will resolve to the
343 // first instance of that symbol
344 if (linkscript.execsym)
345 {
346 lw_expr_stack_t *s;
347
348 s = resolve_sym(linkscript.execsym, 0, NULL);
349 if (!s)
350 {
351 fprintf(stderr, "Cannot resolve exec address '%s'\n", linkscript.execsym);
352 symerr = 1;
353 }
354 else
355 {
356 linkscript.execaddr = lw_expr_get_value(s);
357 lw_expr_stack_free(s);
358 }
359 }
360
361 for (sn = 0; sn < nsects; sn++)
362 {
363 for (rl = sectlist[sn].ptr -> incompletes; rl; rl = rl -> next)
364 {
365 // do a "simplify" on the expression
366 rval = lw_expr_reval(rl -> expr, resolve_sym, sectlist[sn].ptr);
367
368 // is it constant? error out if not
369 if (rval != 0 || !lw_expr_is_constant(rl -> expr))
370 {
371 fprintf(stderr, "Incomplete reference at %s:%s+%02X\n", sectlist[sn].ptr -> file -> filename, sectlist[sn].ptr -> name, rl -> offset);
372 symerr = 1;
373 }
374 else
375 {
376 // put the value into the relocation address
377 rval = lw_expr_get_value(rl -> expr);
378 if (rl -> flags & RELOC_8BIT)
379 {
380 sectlist[sn].ptr -> code[rl -> offset] = rval & 0xff;
381 }
382 else
383 {
384 sectlist[sn].ptr -> code[rl -> offset] = (rval >> 8) & 0xff;
385 sectlist[sn].ptr -> code[rl -> offset + 1] = rval & 0xff;
386 }
387 }
388 }
389 }
390
391 if (symerr)
392 exit(1);
393 }
394
395 /*
396 This is just a pared down version of the algo for resolving references.
397 */
398 void resolve_files(void)
399 {
400 int sn;
401 int fn;
402 reloc_t *rl;
403 lw_expr_stack_t *te;
404
405 int rval;
406
407 // resolve entry point if required
408 // this must resolve to an *exported* symbol and will resolve to the
409 // first instance of that symbol
410 if (linkscript.execsym)
411 {
412 lw_expr_stack_t *s;
413
414 s = resolve_sym(linkscript.execsym, 0, NULL);
415 if (!s)
416 {
417 fprintf(stderr, "Cannot resolve exec address '%s'\n", linkscript.execsym);
418 symerr = 1;
419 }
420 }
421
422 do
423 {
424 nforced = 0;
425 for (fn = 0; fn < ninputfiles; fn++)
426 {
427 if (inputfiles[fn] -> forced == 0)
428 continue;
429
430 for (sn = 0; sn < inputfiles[fn] -> nsections; sn++)
431 {
432 for (rl = inputfiles[fn] -> sections[sn].incompletes; rl; rl = rl -> next)
433 {
434 // do a "simplify" on the expression
435 te = lw_expr_stack_dup(rl -> expr);
436 rval = lw_expr_reval(te, resolve_sym, &(inputfiles[fn] -> sections[sn]));
437
438 // is it constant? error out if not
439 if (rval != 0 || !lw_expr_is_constant(te))
440 {
441 fprintf(stderr, "Incomplete reference at %s:%s+%02X\n", inputfiles[fn] -> filename, inputfiles[fn] -> sections[sn].name, rl -> offset);
442 symerr = 1;
443 }
444 lw_expr_stack_free(te);
445 }
446 }
447 }
448 }
449 while (nforced == 1);
450
451 if (symerr)
452 exit(1);
453
454 // theoretically, all files referenced by other files now have "forced" set to 1
455 for (fn = 0; fn < ninputfiles; fn++)
456 {
457 if (inputfiles[fn] -> forced == 1)
458 continue;
459
460 fprintf(stderr, "Warning: %s (%d) does not resolve any symbols\n", inputfiles[fn] -> filename, fn);
461 }
462 }