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comparison lwlink/link.c @ 139:106c2fe3c9d9

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repo reorg
author lost
date Wed, 28 Jan 2009 05:59:14 +0000
parents lwlink-old/trunk/src/link.c@050864a47b38
children d610b8aef91b
comparison
equal deleted inserted replaced
138:050864a47b38 139:106c2fe3c9d9
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 #ifdef HAVE_CONFIG_H
25 #include "config.h"
26 #endif
27
28 #include <stdio.h>
29 #include <stdlib.h>
30
31 #include "expr.h"
32 #include "lwlink.h"
33 #include "util.h"
34
35 struct section_list *sectlist = NULL;
36 int nsects = 0;
37
38 // work out section load order and resolve base addresses for each section
39 // make a list of sections to load in order
40 void resolve_sections(void)
41 {
42 int laddr = 0;
43 int ln, sn, fn;
44
45 for (ln = 0; ln < linkscript.nlines; ln++)
46 {
47 // printf("Linker script line %d: '%s', %04X, %d, %d\n", ln, linkscript.lines[ln].sectname, linkscript.lines[ln].loadat, linkscript.lines[ln].yesflags, linkscript.lines[ln].noflags);
48 if (linkscript.lines[ln].sectname)
49 {
50 int f = 0;
51 // named section
52 // look for all instances of a section by the specified name
53 // and resolve base addresses and add to the list
54 for (fn = 0; fn < ninputfiles; fn++)
55 {
56 for (sn = 0; sn < inputfiles[fn] -> nsections; sn++)
57 {
58 // printf(" Considering %s:%s\n", inputfiles[fn]->filename, inputfiles[fn]->sections[sn].name);
59 if (!strcmp(linkscript.lines[ln].sectname, inputfiles[fn] -> sections[sn].name))
60 {
61 // we have a match
62 sectlist = lw_realloc(sectlist, sizeof(struct section_list) * (nsects + 1));
63 sectlist[nsects].ptr = &(inputfiles[fn] -> sections[sn]);
64
65 inputfiles[fn] -> sections[sn].processed = 1;
66 if (!f && linkscript.lines[ln].loadat >= 0)
67 {
68 f = 1;
69 sectlist[nsects].forceaddr = 1;
70 laddr = linkscript.lines[ln].loadat;
71 }
72 else
73 {
74 sectlist[nsects].forceaddr = 0;
75 }
76 inputfiles[fn] -> sections[sn].loadaddress = laddr;
77 laddr += inputfiles[fn] -> sections[sn].codesize;
78 nsects++;
79 }
80 }
81 }
82 }
83 else
84 {
85 // wildcard section
86 // look for all sections not yet processed that match flags
87
88 int f = 0;
89 int fn0, sn0;
90 char *sname;
91
92 // named section
93 // look for all instances of a section by the specified name
94 // and resolve base addresses and add to the list
95 for (fn0 = 0; fn0 < ninputfiles; fn0++)
96 {
97 for (sn0 = 0; sn0 < inputfiles[fn0] -> nsections; sn0++)
98 {
99 // ignore if the "no flags" bit says to
100 if (linkscript.lines[ln].noflags && (inputfiles[fn0] -> sections[sn0].flags & linkscript.lines[ln].noflags))
101 continue;
102 // ignore unless the yes flags tell us not to
103 if (linkscript.lines[ln].yesflags && (inputfiles[fn0] -> sections[sn0].flags & linkscript.lines[ln].yesflags == 0))
104 continue;
105 if (inputfiles[fn0] -> sections[sn0].processed == 0)
106 {
107 sname = inputfiles[fn0] -> sections[sn0].name;
108 for (fn = 0; fn < ninputfiles; fn++)
109 {
110 for (sn = 0; sn < inputfiles[fn] -> nsections; sn++)
111 {
112 if (!strcmp(sname, inputfiles[fn] -> sections[sn].name))
113 {
114 // we have a match
115 sectlist = lw_realloc(sectlist, sizeof(struct section_list) * (nsects + 1));
116 sectlist[nsects].ptr = &(inputfiles[fn] -> sections[sn]);
117
118 inputfiles[fn] -> sections[sn].processed = 1;
119 if (!f && linkscript.lines[ln].loadat >= 0)
120 {
121 f = 1;
122 sectlist[nsects].forceaddr = 1;
123 laddr = linkscript.lines[ln].loadat;
124 }
125 else
126 {
127 sectlist[nsects].forceaddr = 0;
128 }
129 inputfiles[fn] -> sections[sn].loadaddress = laddr;
130 laddr += inputfiles[fn] -> sections[sn].codesize;
131 nsects++;
132 }
133 }
134 }
135 }
136 }
137 }
138 }
139 }
140
141 // theoretically, all the base addresses are set now
142 }
143
144 // resolve all incomplete references now
145 // anything that is unresolvable at this stage will throw an error
146 // because we know the load address of every section now
147 lw_expr_stack_t *resolve_sym(char *sym, int symtype, void *state)
148 {
149 section_t *sect = state;
150 lw_expr_term_t *term;
151 int val = 0, i, fn;
152 lw_expr_stack_t *s;
153 symtab_t *se;
154
155 if (symtype == 1)
156 {
157 // local symbol
158 if (!sym)
159 {
160 val = sect -> loadaddress;
161 goto out;
162 }
163
164 // start with this section
165 for (se = sect -> localsyms; se; se = se -> next)
166 {
167 if (!strcmp(se -> sym, sym))
168 {
169 val = se -> offset + sect -> loadaddress;
170 goto out;
171 }
172 }
173 // not in this section - check all sections in this file
174 for (i = 0; i < sect -> file -> nsections; i++)
175 {
176 for (se = sect -> file -> sections[i].localsyms; se; se = se -> next)
177 {
178 if (!strcmp(se -> sym, sym))
179 {
180 val = se -> offset + sect -> file -> sections[i].loadaddress;
181 goto out;
182 }
183 }
184 }
185 // not found
186 fprintf(stderr, "Local symbol %s not found in %s:%s\n", sym, sect -> file -> filename, sect -> name);
187 exit(1);
188 }
189 else
190 {
191 // external symbol
192 // read all files in order until found (or not found)
193 for (fn = 0; fn < ninputfiles; fn++)
194 {
195 for (i = 0; i < inputfiles[fn] -> nsections; i++)
196 {
197 for (se = inputfiles[fn] -> sections[i].exportedsyms; se; se = se -> next)
198 {
199 if (!strcmp(sym, se -> sym))
200 {
201 val = se -> offset + inputfiles[fn] -> sections[i].loadaddress;
202 goto out;
203 }
204 }
205 }
206 }
207 if (sect)
208 {
209 fprintf(stderr, "External symbol %s not found in %s:%s\n", sym, sect -> file -> filename, sect -> name);
210 }
211 else
212 {
213 fprintf(stderr, "External symbol %s not found\n", sym);
214 }
215 exit(1);
216 }
217 fprintf(stderr, "Shouldn't ever get here!!!\n");
218 exit(88);
219 out:
220 s = lw_expr_stack_create();
221 term = lw_expr_term_create_int(val & 0xffff);
222 lw_expr_stack_push(s, term);
223 lw_expr_term_free(term);
224 return s;
225 }
226
227 void resolve_references(void)
228 {
229 int sn;
230 reloc_t *rl;
231 int rval;
232
233 // resolve entry point if required
234 // this must resolve to an *exported* symbol and will resolve to the
235 // first instance of that symbol
236 if (linkscript.execsym)
237 {
238 lw_expr_stack_t *s;
239
240 s = resolve_sym(linkscript.execsym, 0, NULL);
241 linkscript.execaddr = lw_expr_get_value(s);
242 lw_expr_stack_free(s);
243 }
244
245 for (sn = 0; sn < nsects; sn++)
246 {
247 for (rl = sectlist[sn].ptr -> incompletes; rl; rl = rl -> next)
248 {
249 // do a "simplify" on the expression
250 rval = lw_expr_reval(rl -> expr, resolve_sym, sectlist[sn].ptr);
251
252 // is it constant? error out if not
253 if (rval != 0 || !lw_expr_is_constant(rl -> expr))
254 {
255 fprintf(stderr, "Incomplete reference at %s:%s:%02X\n", sectlist[sn].ptr -> file -> filename, sectlist[sn].ptr -> name, rl -> offset);
256 exit(1);
257 }
258
259 // put the value into the relocation address
260 rval = lw_expr_get_value(rl -> expr);
261 sectlist[sn].ptr -> code[rl -> offset] = (rval >> 8) & 0xff;
262 sectlist[sn].ptr -> code[rl -> offset + 1] = rval & 0xff;
263 }
264 }
265 }