1
2 /*--------------------------------------------------------------------*/
3 /*--- Read stabs debug info. readstabs.c ---*/
4 /*--------------------------------------------------------------------*/
5
6 /*
7 This file is part of Valgrind, a dynamic binary instrumentation
8 framework.
9
10 Copyright (C) 2000-2012 Julian Seward
11 jseward@acm.org
12
13 This program is free software; you can redistribute it and/or
14 modify it under the terms of the GNU General Public License as
15 published by the Free Software Foundation; either version 2 of the
16 License, or (at your option) any later version.
17
18 This program is distributed in the hope that it will be useful, but
19 WITHOUT ANY WARRANTY; without even the implied warranty of
20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21 General Public License for more details.
22
23 You should have received a copy of the GNU General Public License
24 along with this program; if not, write to the Free Software
25 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26 02111-1307, USA.
27
28 The GNU General Public License is contained in the file COPYING.
29 */
30
31 /*
32 Stabs reader greatly improved by Nick Nethercote, Apr 02.
33 This module was also extensively hacked on by Jeremy Fitzhardinge
34 and Tom Hughes.
35 */
36
37 /* "on Linux (except android), or on Darwin" */
38 #if (defined(VGO_linux) && \
39 !(defined(VGPV_arm_linux_android) || defined(VGPV_x86_linux_android)) \
40 || defined(VGO_darwin))
41
42 #include "pub_core_basics.h"
43 #include "pub_core_debuginfo.h"
44 #include "pub_core_libcbase.h"
45 #include "pub_core_libcassert.h"
46 #include "pub_core_libcprint.h"
47 #include "pub_core_xarray.h"
48 #include "priv_misc.h" /* dinfo_zalloc/free/strdup */
49 #include "priv_tytypes.h"
50 #include "priv_d3basics.h"
51 #include "priv_storage.h"
52 #include "priv_readstabs.h" /* self */
53
54 /* --- !!! --- EXTERNAL HEADERS start --- !!! --- */
55 #if defined(VGO_linux)
56 # include <a.out.h> /* stabs defns */
57 #elif defined(VGO_darwin)
58 # include <mach-o/nlist.h>
59 # define n_other n_sect
60 # if VG_WORDSIZE == 8
61 # define nlist nlist_64
62 # endif
63 #else
64 # error "Unknown OS"
65 #endif
66 /* --- !!! --- EXTERNAL HEADERS end --- !!! --- */
67
68 /*------------------------------------------------------------*/
69 /*--- Read STABS format debug info. ---*/
70 /*------------------------------------------------------------*/
71
72 /* Stabs entry types, from:
73 * The "stabs" debug format
74 * Menapace, Kingdon and MacKenzie
75 * Cygnus Support
76 */
77 typedef enum { N_UNDEF = 0, /* undefined symbol, new stringtab */
78 N_GSYM = 32, /* Global symbol */
79 N_FUN = 36, /* Function start or end */
80 N_STSYM = 38, /* Data segment file-scope variable */
81 N_LCSYM = 40, /* BSS segment file-scope variable */
82 N_RSYM = 64, /* Register variable */
83 N_SLINE = 68, /* Source line number */
84 N_SO = 100, /* Source file path and name */
85 N_LSYM = 128, /* Stack variable or type */
86 N_BINCL = 130, /* Beginning of an include file */
87 N_SOL = 132, /* Include file name */
88 N_PSYM = 160, /* Function parameter */
89 N_EINCL = 162, /* End of an include file */
90 N_LBRAC = 192, /* Start of lexical block */
91 N_EXCL = 194, /* Placeholder for an include file */
92 N_RBRAC = 224 /* End of lexical block */
93 } stab_types;
94
95
96 /* Read stabs-format debug info. This is all rather horrible because
97 stabs is a underspecified, kludgy hack.
98 */
ML_(read_debuginfo_stabs)99 void ML_(read_debuginfo_stabs) ( DebugInfo* di,
100 UChar* stabC, Int stab_sz,
101 UChar* stabstr, Int stabstr_sz )
102 {
103 const Bool debug = False;
104 const Bool contdebug = False;
105 Int i;
106 Int n_stab_entries;
107 struct nlist* stab = (struct nlist*)stabC;
108 UChar *next_stabstr = NULL;
109 /* state for various things */
110 struct {
111 Addr start; /* start address */
112 Addr end; /* end address */
113 Int line; /* first line */
114 } func = { 0, 0, -1 };
115 struct {
116 Char *name;
117 Bool same;
118 } file = { NULL, True };
119 struct {
120 Int prev; /* prev line */
121 Int no; /* current line */
122 Int ovf; /* line wrap */
123 Addr addr; /* start of this line */
124 Bool first; /* first line in function */
125 } line = { 0, 0, 0, 0, False };
126
127 /* Ok. It all looks plausible. Go on and read debug data.
128 stab kinds: 100 N_SO a source file name
129 68 N_SLINE a source line number
130 36 N_FUN start of a function
131
132 In this loop, we maintain a current file name, updated as
133 N_SO/N_SOLs appear, and a current function base address,
134 updated as N_FUNs appear. Based on that, address ranges for
135 N_SLINEs are calculated, and stuffed into the line info table.
136
137 Finding the instruction address range covered by an N_SLINE is
138 complicated; see the N_SLINE case below.
139 */
140 file.name = ML_(addStr)(di,"???", -1);
141
142 n_stab_entries = stab_sz/(int)sizeof(struct nlist);
143
144 for (i = 0; i < n_stab_entries; i++) {
145 const struct nlist *st = &stab[i];
146 Char *string;
147
148 if (di->trace_symtab) {
149 VG_(printf) ( "%2d type=%d othr=%d desc=%d "
150 "value=0x%x strx=%d %s\n", i,
151 st->n_type, st->n_other, st->n_desc,
152 (Int)st->n_value,
153 (Int)st->n_un.n_strx,
154 stabstr + st->n_un.n_strx );
155 }
156
157 /* handle continued string stabs */
158 {
159 Int qbuflen = 0;
160 Int qidx = 0;
161 Char* qbuf = NULL;
162 Int qlen;
163 Bool qcontinuing = False;
164 UInt qstringidx;
165
166 qstringidx = st->n_un.n_strx;
167 string = stabstr + qstringidx;
168 qlen = VG_(strlen)(string);
169
170 while (string
171 && qlen > 0
172 && (qcontinuing || string[qlen-1] == '\\')) {
173 /* Gak, we have a continuation. Skip forward through
174 subsequent stabs to gather all the parts of the
175 continuation. Increment i, but keep st pointing at
176 current stab. */
177
178 qcontinuing = string[qlen-1] == '\\';
179
180 /* remove trailing \ */
181 while (string[qlen-1] == '\\' && qlen > 0)
182 qlen--;
183
184 if (contdebug)
185 VG_(printf)("found extension string: \"%s\" "
186 "len=%d(%c) idx=%d buflen=%d\n",
187 string, qlen, string[qlen-1], qidx, qbuflen);
188
189 /* XXX this is silly. The si->strtab should have a way of
190 appending to the last added string... */
191 if ((qidx + qlen) >= qbuflen) {
192 Char *n;
193
194 if (qbuflen == 0)
195 qbuflen = 16;
196 while ((qidx + qlen) >= qbuflen)
197 qbuflen *= 2;
198 n = ML_(dinfo_zalloc)("di.readstabs.rds.1", qbuflen);
199 VG_(memcpy)(n, qbuf, qidx);
200
201 if (qbuf != NULL)
202 ML_(dinfo_free)(qbuf);
203 qbuf = n;
204 }
205
206 VG_(memcpy)(&qbuf[qidx], string, qlen);
207 qidx += qlen;
208 if (contdebug) {
209 qbuf[qidx] = '\0';
210 VG_(printf)("working buf=\"%s\"\n", qbuf);
211 }
212
213 i++;
214 if (i >= n_stab_entries)
215 break;
216
217 if (stab[i].n_un.n_strx) {
218 string = stabstr + stab[i].n_un.n_strx;
219 qlen = VG_(strlen)(string);
220 } else {
221 string = NULL;
222 qlen = 0;
223 }
224 }
225
226 if (qbuf != NULL) {
227 i--; /* overstepped */
228 string = ML_(addStr)(di, qbuf, qidx);
229 ML_(dinfo_free)(qbuf);
230 if (contdebug)
231 VG_(printf)("made composite: \"%s\"\n", string);
232 }
233 }
234
235 switch(st->n_type) {
236 case N_UNDEF:
237 /* new string table base */
238 if (next_stabstr != NULL) {
239 stabstr_sz -= next_stabstr - stabstr;
240 stabstr = next_stabstr;
241 if (stabstr_sz <= 0) {
242 VG_(printf)(" @@ bad stabstr size %d\n", stabstr_sz);
243 return;
244 }
245 }
246 next_stabstr = stabstr + st->n_value;
247 break;
248
249 case N_BINCL: {
250 break;
251 }
252
253 case N_EINCL:
254 break;
255
256 case N_EXCL:
257 break;
258
259 case N_SOL: /* sub-source (include) file */
260 if (line.ovf != 0)
261 VG_(message)(Vg_UserMsg,
262 "Warning: file %s is very big (> 65535 lines) "
263 "Line numbers and annotation for this file might "
264 "be wrong. Sorry.\n",
265 file.name);
266 /* FALLTHROUGH */
267
268 case N_SO: { /* new source file */
269 UChar *nm = string;
270 UInt len = VG_(strlen)(nm);
271 Addr addr = func.start + st->n_value;
272
273 if (line.addr != 0) {
274 /* finish off previous line */
275 ML_(addLineInfo)(di, file.name, NULL, line.addr,
276 addr, line.no + line.ovf * LINENO_OVERFLOW, i);
277 }
278
279 /* reset line state */
280 line.ovf = 0;
281 line.addr = 0;
282 line.prev = 0;
283 line.no = 0;
284
285 if (len > 0 && nm[len-1] != '/') {
286 file.name = ML_(addStr)(di, nm, -1);
287 if (debug)
288 VG_(printf)("new source: %s\n", file.name);
289 } else if (len == 0)
290 file.name = ML_(addStr)(di, "?1\0", -1);
291
292 break;
293 }
294
295 case N_SLINE: { /* line info */
296 Addr addr = func.start + st->n_value;
297
298 if (line.addr != 0) {
299 /* there was a previous */
300 ML_(addLineInfo)(di, file.name, NULL, line.addr,
301 addr, line.no + line.ovf * LINENO_OVERFLOW, i);
302 }
303
304 line.addr = addr;
305 line.prev = line.no;
306 line.no = (Int)((UShort)st->n_desc);
307
308 if (line.prev > line.no + OVERFLOW_DIFFERENCE && file.same) {
309 VG_(message)(Vg_DebugMsg,
310 "Line number overflow detected (%d --> %d) in %s\n",
311 line.prev, line.no, file.name);
312 line.ovf++;
313 }
314 file.same = True;
315
316 /* This is pretty horrible. If this is the first line of
317 the function, then bind any unbound symbols to the arg
318 scope, since they're probably arguments. */
319 if (line.first) {
320 line.first = False;
321
322 /* remember first line of function */
323 if (func.start != 0) {
324 func.line = line.no;
325 }
326 }
327 break;
328 }
329
330 case N_FUN: { /* function start/end */
331 Addr addr = 0; /* end address for prev line/scope */
332
333 /* if this the end of the function or we haven't
334 previously finished the previous function... */
335 if (*string == '\0' || func.start != 0) {
336 /* end of function */
337 line.first = False;
338
339 /* end line at end of function */
340 addr = func.start + st->n_value;
341
342 /* now between functions */
343 func.start = 0;
344
345 // XXXX DEAD POINT XXXX
346 }
347
348 if (*string != '\0') {
349 /* new function */
350 line.first = True;
351
352 /* line ends at start of next function */
353 addr = di->text_debug_bias + st->n_value;
354
355 func.start = addr;
356 }
357
358 if (line.addr) {
359 ML_(addLineInfo)(di, file.name, NULL, line.addr,
360 addr, line.no + line.ovf * LINENO_OVERFLOW, i);
361 line.addr = 0;
362 }
363
364 //DEAD POINT
365 //DEAD POINT
366 break;
367 }
368
369 case N_LBRAC: {
370 /* open new scope */
371 // DEAD POINT
372 break;
373 }
374
375 case N_RBRAC: {
376 /* close scope */
377 // DEAD POINT
378 break;
379 }
380
381 case N_GSYM: /* global variable */
382 case N_STSYM: /* static in data segment */
383 case N_LCSYM: /* static in bss segment */
384 case N_PSYM: /* function parameter */
385 case N_LSYM: /* stack variable */
386 case N_RSYM: /* register variable */
387 break;
388 }
389 }
390 }
391
392 #endif /* (defined(VGO_linux) && !defined(VGPV_*_linux_android)) \
393 || defined(VGO_darwin) */
394
395 /*--------------------------------------------------------------------*/
396 /*--- end ---*/
397 /*--------------------------------------------------------------------*/
398