1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
|
/* DWARF 1 find nearest line (_bfd_dwarf1_find_nearest_line).
Copyright 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2007, 2008
Free Software Foundation, Inc.
Written by Gavin Romig-Koch of Cygnus Solutions (gavin@cygnus.com).
This file is part of BFD.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
#include "sysdep.h"
#include "bfd.h"
#include "libiberty.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "elf/dwarf.h"
/* dwarf1_debug is the starting point for all dwarf1 info. */
struct dwarf1_debug
{
/* The bfd we are working with. */
bfd* abfd;
/* Pointer to the symbol table. */
asymbol** syms;
/* List of already parsed compilation units. */
struct dwarf1_unit* lastUnit;
/* The buffer for the .debug section.
Zero indicates that the .debug section failed to load. */
bfd_byte *debug_section;
/* Pointer to the end of the .debug_info section memory buffer. */
bfd_byte *debug_section_end;
/* The buffer for the .line section. */
bfd_byte *line_section;
/* End of that buffer. */
bfd_byte *line_section_end;
/* The current or next unread die within the .debug section. */
bfd_byte *currentDie;
};
/* One dwarf1_unit for each parsed compilation unit die. */
struct dwarf1_unit
{
/* Linked starting from stash->lastUnit. */
struct dwarf1_unit* prev;
/* Name of the compilation unit. */
char *name;
/* The highest and lowest address used in the compilation unit. */
unsigned long low_pc;
unsigned long high_pc;
/* Does this unit have a statement list? */
int has_stmt_list;
/* If any, the offset of the line number table in the .line section. */
unsigned long stmt_list_offset;
/* If non-zero, a pointer to the first child of this unit. */
bfd_byte *first_child;
/* How many line entries? */
unsigned long line_count;
/* The decoded line number table (line_count entries). */
struct linenumber* linenumber_table;
/* The list of functions in this unit. */
struct dwarf1_func* func_list;
};
/* One dwarf1_func for each parsed function die. */
struct dwarf1_func
{
/* Linked starting from aUnit->func_list. */
struct dwarf1_func* prev;
/* Name of function. */
char* name;
/* The highest and lowest address used in the compilation unit. */
unsigned long low_pc;
unsigned long high_pc;
};
/* Used to return info about a parsed die. */
struct die_info
{
unsigned long length;
unsigned long sibling;
unsigned long low_pc;
unsigned long high_pc;
unsigned long stmt_list_offset;
char* name;
int has_stmt_list;
unsigned short tag;
};
/* Parsed line number information. */
struct linenumber
{
/* First address in the line. */
unsigned long addr;
/* The line number. */
unsigned long linenumber;
};
/* Find the form of an attr, from the attr field. */
#define FORM_FROM_ATTR(attr) ((attr) & 0xF) /* Implicitly specified. */
/* Return a newly allocated dwarf1_unit. It should be cleared and
then attached into the 'stash' at 'stash->lastUnit'. */
static struct dwarf1_unit*
alloc_dwarf1_unit (struct dwarf1_debug* stash)
{
bfd_size_type amt = sizeof (struct dwarf1_unit);
struct dwarf1_unit* x = bfd_zalloc (stash->abfd, amt);
if (x)
{
x->prev = stash->lastUnit;
stash->lastUnit = x;
}
return x;
}
/* Return a newly allocated dwarf1_func. It must be cleared and
attached into 'aUnit' at 'aUnit->func_list'. */
static struct dwarf1_func *
alloc_dwarf1_func (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
{
bfd_size_type amt = sizeof (struct dwarf1_func);
struct dwarf1_func* x = bfd_zalloc (stash->abfd, amt);
if (x)
{
x->prev = aUnit->func_list;
aUnit->func_list = x;
}
return x;
}
/* parse_die - parse a Dwarf1 die.
Parse the die starting at 'aDiePtr' into 'aDieInfo'.
'abfd' must be the bfd from which the section that 'aDiePtr'
points to was pulled from.
Return FALSE if the die is invalidly formatted; TRUE otherwise. */
static bfd_boolean
parse_die (bfd * abfd,
struct die_info * aDieInfo,
bfd_byte * aDiePtr,
bfd_byte * aDiePtrEnd)
{
bfd_byte *this_die = aDiePtr;
bfd_byte *xptr = this_die;
memset (aDieInfo, 0, sizeof (* aDieInfo));
/* First comes the length. */
aDieInfo->length = bfd_get_32 (abfd, (bfd_byte *) xptr);
xptr += 4;
if (aDieInfo->length == 0
|| (this_die + aDieInfo->length) >= aDiePtrEnd)
return FALSE;
if (aDieInfo->length < 6)
{
/* Just padding bytes. */
aDieInfo->tag = TAG_padding;
return TRUE;
}
/* Then the tag. */
aDieInfo->tag = bfd_get_16 (abfd, (bfd_byte *) xptr);
xptr += 2;
/* Then the attributes. */
while (xptr < (this_die + aDieInfo->length))
{
unsigned short attr;
/* Parse the attribute based on its form. This section
must handle all dwarf1 forms, but need only handle the
actual attributes that we care about. */
attr = bfd_get_16 (abfd, (bfd_byte *) xptr);
xptr += 2;
switch (FORM_FROM_ATTR (attr))
{
case FORM_DATA2:
xptr += 2;
break;
case FORM_DATA4:
case FORM_REF:
if (attr == AT_sibling)
aDieInfo->sibling = bfd_get_32 (abfd, (bfd_byte *) xptr);
else if (attr == AT_stmt_list)
{
aDieInfo->stmt_list_offset = bfd_get_32 (abfd, (bfd_byte *) xptr);
aDieInfo->has_stmt_list = 1;
}
xptr += 4;
break;
case FORM_DATA8:
xptr += 8;
break;
case FORM_ADDR:
if (attr == AT_low_pc)
aDieInfo->low_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
else if (attr == AT_high_pc)
aDieInfo->high_pc = bfd_get_32 (abfd, (bfd_byte *) xptr);
xptr += 4;
break;
case FORM_BLOCK2:
xptr += 2 + bfd_get_16 (abfd, (bfd_byte *) xptr);
break;
case FORM_BLOCK4:
xptr += 4 + bfd_get_32 (abfd, (bfd_byte *) xptr);
break;
case FORM_STRING:
if (attr == AT_name)
aDieInfo->name = (char *)xptr;
xptr += strlen (aDieInfo->name) + 1;
break;
}
}
return TRUE;
}
/* Parse a dwarf1 line number table for 'aUnit->stmt_list_offset'
into 'aUnit->linenumber_table'. Return FALSE if an error
occurs; TRUE otherwise. */
static bfd_boolean
parse_line_table (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
{
bfd_byte *xptr;
/* Load the ".line" section from the bfd if we haven't already. */
if (stash->line_section == 0)
{
asection *msec;
bfd_size_type size;
msec = bfd_get_section_by_name (stash->abfd, ".line");
if (! msec)
return FALSE;
size = msec->rawsize ? msec->rawsize : msec->size;
stash->line_section
= bfd_simple_get_relocated_section_contents
(stash->abfd, msec, NULL, stash->syms);
if (! stash->line_section)
return FALSE;
stash->line_section_end = stash->line_section + size;
}
xptr = stash->line_section + aUnit->stmt_list_offset;
if (xptr < stash->line_section_end)
{
unsigned long eachLine;
bfd_byte *tblend;
unsigned long base;
bfd_size_type amt;
/* First comes the length. */
tblend = bfd_get_32 (stash->abfd, (bfd_byte *) xptr) + xptr;
xptr += 4;
/* Then the base address for each address in the table. */
base = bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
xptr += 4;
/* How many line entrys?
10 = 4 (line number) + 2 (pos in line) + 4 (address in line). */
aUnit->line_count = (tblend - xptr) / 10;
/* Allocate an array for the entries. */
amt = sizeof (struct linenumber) * aUnit->line_count;
aUnit->linenumber_table = bfd_alloc (stash->abfd, amt);
if (!aUnit->linenumber_table)
return FALSE;
for (eachLine = 0; eachLine < aUnit->line_count; eachLine++)
{
/* A line number. */
aUnit->linenumber_table[eachLine].linenumber
= bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
xptr += 4;
/* Skip the position within the line. */
xptr += 2;
/* And finally the address. */
aUnit->linenumber_table[eachLine].addr
= base + bfd_get_32 (stash->abfd, (bfd_byte *) xptr);
xptr += 4;
}
}
return TRUE;
}
/* Parse each function die in a compilation unit 'aUnit'.
The first child die of 'aUnit' should be in 'aUnit->first_child',
the result is placed in 'aUnit->func_list'.
Return FALSE if error; TRUE otherwise. */
static bfd_boolean
parse_functions_in_unit (struct dwarf1_debug* stash, struct dwarf1_unit* aUnit)
{
bfd_byte *eachDie;
if (aUnit->first_child)
for (eachDie = aUnit->first_child;
eachDie < stash->debug_section_end;
)
{
struct die_info eachDieInfo;
if (! parse_die (stash->abfd, &eachDieInfo, eachDie,
stash->debug_section_end))
return FALSE;
if (eachDieInfo.tag == TAG_global_subroutine
|| eachDieInfo.tag == TAG_subroutine
|| eachDieInfo.tag == TAG_inlined_subroutine
|| eachDieInfo.tag == TAG_entry_point)
{
struct dwarf1_func* aFunc = alloc_dwarf1_func (stash,aUnit);
if (!aFunc)
return FALSE;
aFunc->name = eachDieInfo.name;
aFunc->low_pc = eachDieInfo.low_pc;
aFunc->high_pc = eachDieInfo.high_pc;
}
/* Move to next sibling, if none, end loop */
if (eachDieInfo.sibling)
eachDie = stash->debug_section + eachDieInfo.sibling;
else
break;
}
return TRUE;
}
/* Find the nearest line to 'addr' in 'aUnit'.
Return whether we found the line (or a function) without error. */
static bfd_boolean
dwarf1_unit_find_nearest_line (struct dwarf1_debug* stash,
struct dwarf1_unit* aUnit,
unsigned long addr,
const char **filename_ptr,
const char **functionname_ptr,
unsigned int *linenumber_ptr)
{
int line_p = FALSE;
int func_p = FALSE;
if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
{
if (aUnit->has_stmt_list)
{
unsigned long i;
struct dwarf1_func* eachFunc;
if (! aUnit->linenumber_table)
{
if (! parse_line_table (stash, aUnit))
return FALSE;
}
if (! aUnit->func_list)
{
if (! parse_functions_in_unit (stash, aUnit))
return FALSE;
}
for (i = 0; i < aUnit->line_count; i++)
{
if (aUnit->linenumber_table[i].addr <= addr
&& addr < aUnit->linenumber_table[i+1].addr)
{
*filename_ptr = aUnit->name;
*linenumber_ptr = aUnit->linenumber_table[i].linenumber;
line_p = TRUE;
break;
}
}
for (eachFunc = aUnit->func_list;
eachFunc;
eachFunc = eachFunc->prev)
{
if (eachFunc->low_pc <= addr
&& addr < eachFunc->high_pc)
{
*functionname_ptr = eachFunc->name;
func_p = TRUE;
break;
}
}
}
}
return line_p || func_p;
}
/* The DWARF 1 version of find_nearest line.
Return TRUE if the line is found without error. */
bfd_boolean
_bfd_dwarf1_find_nearest_line (bfd *abfd,
asection *section,
asymbol **symbols,
bfd_vma offset,
const char **filename_ptr,
const char **functionname_ptr,
unsigned int *linenumber_ptr)
{
struct dwarf1_debug *stash = elf_tdata (abfd)->dwarf1_find_line_info;
struct dwarf1_unit* eachUnit;
/* What address are we looking for? */
unsigned long addr = (unsigned long)(offset + section->vma);
*filename_ptr = NULL;
*functionname_ptr = NULL;
*linenumber_ptr = 0;
if (! stash)
{
asection *msec;
bfd_size_type size = sizeof (struct dwarf1_debug);
stash = elf_tdata (abfd)->dwarf1_find_line_info
= bfd_zalloc (abfd, size);
if (! stash)
return FALSE;
msec = bfd_get_section_by_name (abfd, ".debug");
if (! msec)
/* No dwarf1 info. Note that at this point the stash
has been allocated, but contains zeros, this lets
future calls to this function fail quicker. */
return FALSE;
size = msec->rawsize ? msec->rawsize : msec->size;
stash->debug_section
= bfd_simple_get_relocated_section_contents (abfd, msec, NULL,
symbols);
if (! stash->debug_section)
return FALSE;
stash->debug_section_end = stash->debug_section + size;
stash->currentDie = stash->debug_section;
stash->abfd = abfd;
stash->syms = symbols;
}
/* A null debug_section indicates that there was no dwarf1 info
or that an error occured while setting up the stash. */
if (! stash->debug_section)
return FALSE;
/* Look at the previously parsed units to see if any contain
the addr. */
for (eachUnit = stash->lastUnit; eachUnit; eachUnit = eachUnit->prev)
if (eachUnit->low_pc <= addr && addr < eachUnit->high_pc)
return dwarf1_unit_find_nearest_line (stash, eachUnit, addr,
filename_ptr,
functionname_ptr,
linenumber_ptr);
while (stash->currentDie < stash->debug_section_end)
{
struct die_info aDieInfo;
if (! parse_die (stash->abfd, &aDieInfo, stash->currentDie,
stash->debug_section_end))
return FALSE;
if (aDieInfo.tag == TAG_compile_unit)
{
struct dwarf1_unit* aUnit
= alloc_dwarf1_unit (stash);
if (!aUnit)
return FALSE;
aUnit->name = aDieInfo.name;
aUnit->low_pc = aDieInfo.low_pc;
aUnit->high_pc = aDieInfo.high_pc;
aUnit->has_stmt_list = aDieInfo.has_stmt_list;
aUnit->stmt_list_offset = aDieInfo.stmt_list_offset;
/* A die has a child if it's followed by a die that is
not it's sibling. */
if (aDieInfo.sibling
&& stash->currentDie + aDieInfo.length
< stash->debug_section_end
&& stash->currentDie + aDieInfo.length
!= stash->debug_section + aDieInfo.sibling)
aUnit->first_child = stash->currentDie + aDieInfo.length;
else
aUnit->first_child = 0;
if (aUnit->low_pc <= addr && addr < aUnit->high_pc)
return dwarf1_unit_find_nearest_line (stash, aUnit, addr,
filename_ptr,
functionname_ptr,
linenumber_ptr);
}
if (aDieInfo.sibling != 0)
stash->currentDie = stash->debug_section + aDieInfo.sibling;
else
stash->currentDie += aDieInfo.length;
}
return FALSE;
}
|