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1/*
2 * dwarf-aux.c : libdw auxiliary interfaces
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 */
19
20#include <stdbool.h>
21#include "util.h"
22#include "debug.h"
23#include "dwarf-aux.h"
24
25/**
26 * cu_find_realpath - Find the realpath of the target file
27 * @cu_die: A DIE(dwarf information entry) of CU(compilation Unit)
28 * @fname: The tail filename of the target file
29 *
30 * Find the real(long) path of @fname in @cu_die.
31 */
32const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
33{
34 Dwarf_Files *files;
35 size_t nfiles, i;
36 const char *src = NULL;
37 int ret;
38
39 if (!fname)
40 return NULL;
41
42 ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
43 if (ret != 0)
44 return NULL;
45
46 for (i = 0; i < nfiles; i++) {
47 src = dwarf_filesrc(files, i, NULL, NULL);
48 if (strtailcmp(src, fname) == 0)
49 break;
50 }
51 if (i == nfiles)
52 return NULL;
53 return src;
54}
55
56/**
57 * cu_get_comp_dir - Get the path of compilation directory
58 * @cu_die: a CU DIE
59 *
60 * Get the path of compilation directory of given @cu_die.
61 * Since this depends on DW_AT_comp_dir, older gcc will not
62 * embedded it. In that case, this returns NULL.
63 */
64const char *cu_get_comp_dir(Dwarf_Die *cu_die)
65{
66 Dwarf_Attribute attr;
67 if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
68 return NULL;
69 return dwarf_formstring(&attr);
70}
71
72/**
73 * cu_find_lineinfo - Get a line number and file name for given address
74 * @cu_die: a CU DIE
75 * @addr: An address
76 * @fname: a pointer which returns the file name string
77 * @lineno: a pointer which returns the line number
78 *
79 * Find a line number and file name for @addr in @cu_die.
80 */
81int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr,
82 const char **fname, int *lineno)
83{
84 Dwarf_Line *line;
85 Dwarf_Addr laddr;
86
87 line = dwarf_getsrc_die(cu_die, (Dwarf_Addr)addr);
88 if (line && dwarf_lineaddr(line, &laddr) == 0 &&
89 addr == (unsigned long)laddr && dwarf_lineno(line, lineno) == 0) {
90 *fname = dwarf_linesrc(line, NULL, NULL);
91 if (!*fname)
92 /* line number is useless without filename */
93 *lineno = 0;
94 }
95
96 return *lineno ?: -ENOENT;
97}
98
99static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
100
101/**
102 * cu_walk_functions_at - Walk on function DIEs at given address
103 * @cu_die: A CU DIE
104 * @addr: An address
105 * @callback: A callback which called with found DIEs
106 * @data: A user data
107 *
108 * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
109 * should be subprogram or inlined-subroutines.
110 */
111int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
112 int (*callback)(Dwarf_Die *, void *), void *data)
113{
114 Dwarf_Die die_mem;
115 Dwarf_Die *sc_die;
116 int ret = -ENOENT;
117
118 /* Inlined function could be recursive. Trace it until fail */
119 for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
120 sc_die != NULL;
121 sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
122 &die_mem)) {
123 ret = callback(sc_die, data);
124 if (ret)
125 break;
126 }
127
128 return ret;
129
130}
131
132/**
133 * die_compare_name - Compare diename and tname
134 * @dw_die: a DIE
135 * @tname: a string of target name
136 *
137 * Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
138 */
139bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
140{
141 const char *name;
142 name = dwarf_diename(dw_die);
143 return name ? (strcmp(tname, name) == 0) : false;
144}
145
146/**
147 * die_get_call_lineno - Get callsite line number of inline-function instance
148 * @in_die: a DIE of an inlined function instance
149 *
150 * Get call-site line number of @in_die. This means from where the inline
151 * function is called.
152 */
153int die_get_call_lineno(Dwarf_Die *in_die)
154{
155 Dwarf_Attribute attr;
156 Dwarf_Word ret;
157
158 if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
159 return -ENOENT;
160
161 dwarf_formudata(&attr, &ret);
162 return (int)ret;
163}
164
165/**
166 * die_get_type - Get type DIE
167 * @vr_die: a DIE of a variable
168 * @die_mem: where to store a type DIE
169 *
170 * Get a DIE of the type of given variable (@vr_die), and store
171 * it to die_mem. Return NULL if fails to get a type DIE.
172 */
173Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
174{
175 Dwarf_Attribute attr;
176
177 if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
178 dwarf_formref_die(&attr, die_mem))
179 return die_mem;
180 else
181 return NULL;
182}
183
184/* Get a type die, but skip qualifiers */
185static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
186{
187 int tag;
188
189 do {
190 vr_die = die_get_type(vr_die, die_mem);
191 if (!vr_die)
192 break;
193 tag = dwarf_tag(vr_die);
194 } while (tag == DW_TAG_const_type ||
195 tag == DW_TAG_restrict_type ||
196 tag == DW_TAG_volatile_type ||
197 tag == DW_TAG_shared_type);
198
199 return vr_die;
200}
201
202/**
203 * die_get_real_type - Get a type die, but skip qualifiers and typedef
204 * @vr_die: a DIE of a variable
205 * @die_mem: where to store a type DIE
206 *
207 * Get a DIE of the type of given variable (@vr_die), and store
208 * it to die_mem. Return NULL if fails to get a type DIE.
209 * If the type is qualifiers (e.g. const) or typedef, this skips it
210 * and tries to find real type (structure or basic types, e.g. int).
211 */
212Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
213{
214 do {
215 vr_die = __die_get_real_type(vr_die, die_mem);
216 } while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
217
218 return vr_die;
219}
220
221/* Get attribute and translate it as a udata */
222static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
223 Dwarf_Word *result)
224{
225 Dwarf_Attribute attr;
226
227 if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
228 dwarf_formudata(&attr, result) != 0)
229 return -ENOENT;
230
231 return 0;
232}
233
234/* Get attribute and translate it as a sdata */
235static int die_get_attr_sdata(Dwarf_Die *tp_die, unsigned int attr_name,
236 Dwarf_Sword *result)
237{
238 Dwarf_Attribute attr;
239
240 if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
241 dwarf_formsdata(&attr, result) != 0)
242 return -ENOENT;
243
244 return 0;
245}
246
247/**
248 * die_is_signed_type - Check whether a type DIE is signed or not
249 * @tp_die: a DIE of a type
250 *
251 * Get the encoding of @tp_die and return true if the encoding
252 * is signed.
253 */
254bool die_is_signed_type(Dwarf_Die *tp_die)
255{
256 Dwarf_Word ret;
257
258 if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
259 return false;
260
261 return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
262 ret == DW_ATE_signed_fixed);
263}
264
265/**
266 * die_get_data_member_location - Get the data-member offset
267 * @mb_die: a DIE of a member of a data structure
268 * @offs: The offset of the member in the data structure
269 *
270 * Get the offset of @mb_die in the data structure including @mb_die, and
271 * stores result offset to @offs. If any error occurs this returns errno.
272 */
273int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
274{
275 Dwarf_Attribute attr;
276 Dwarf_Op *expr;
277 size_t nexpr;
278 int ret;
279
280 if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
281 return -ENOENT;
282
283 if (dwarf_formudata(&attr, offs) != 0) {
284 /* DW_AT_data_member_location should be DW_OP_plus_uconst */
285 ret = dwarf_getlocation(&attr, &expr, &nexpr);
286 if (ret < 0 || nexpr == 0)
287 return -ENOENT;
288
289 if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
290 pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
291 expr[0].atom, nexpr);
292 return -ENOTSUP;
293 }
294 *offs = (Dwarf_Word)expr[0].number;
295 }
296 return 0;
297}
298
299/* Get the call file index number in CU DIE */
300static int die_get_call_fileno(Dwarf_Die *in_die)
301{
302 Dwarf_Sword idx;
303
304 if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0)
305 return (int)idx;
306 else
307 return -ENOENT;
308}
309
310/* Get the declared file index number in CU DIE */
311static int die_get_decl_fileno(Dwarf_Die *pdie)
312{
313 Dwarf_Sword idx;
314
315 if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0)
316 return (int)idx;
317 else
318 return -ENOENT;
319}
320
321/**
322 * die_get_call_file - Get callsite file name of inlined function instance
323 * @in_die: a DIE of an inlined function instance
324 *
325 * Get call-site file name of @in_die. This means from which file the inline
326 * function is called.
327 */
328const char *die_get_call_file(Dwarf_Die *in_die)
329{
330 Dwarf_Die cu_die;
331 Dwarf_Files *files;
332 int idx;
333
334 idx = die_get_call_fileno(in_die);
335 if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
336 dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
337 return NULL;
338
339 return dwarf_filesrc(files, idx, NULL, NULL);
340}
341
342
343/**
344 * die_find_child - Generic DIE search function in DIE tree
345 * @rt_die: a root DIE
346 * @callback: a callback function
347 * @data: a user data passed to the callback function
348 * @die_mem: a buffer for result DIE
349 *
350 * Trace DIE tree from @rt_die and call @callback for each child DIE.
351 * If @callback returns DIE_FIND_CB_END, this stores the DIE into
352 * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
353 * this continues to trace the tree. Optionally, @callback can return
354 * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
355 * the children and trace only the siblings respectively.
356 * Returns NULL if @callback can't find any appropriate DIE.
357 */
358Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
359 int (*callback)(Dwarf_Die *, void *),
360 void *data, Dwarf_Die *die_mem)
361{
362 Dwarf_Die child_die;
363 int ret;
364
365 ret = dwarf_child(rt_die, die_mem);
366 if (ret != 0)
367 return NULL;
368
369 do {
370 ret = callback(die_mem, data);
371 if (ret == DIE_FIND_CB_END)
372 return die_mem;
373
374 if ((ret & DIE_FIND_CB_CHILD) &&
375 die_find_child(die_mem, callback, data, &child_die)) {
376 memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
377 return die_mem;
378 }
379 } while ((ret & DIE_FIND_CB_SIBLING) &&
380 dwarf_siblingof(die_mem, die_mem) == 0);
381
382 return NULL;
383}
384
385struct __addr_die_search_param {
386 Dwarf_Addr addr;
387 Dwarf_Die *die_mem;
388};
389
390/* die_find callback for non-inlined function search */
391static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
392{
393 struct __addr_die_search_param *ad = data;
394
395 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
396 dwarf_haspc(fn_die, ad->addr)) {
397 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
398 return DWARF_CB_ABORT;
399 }
400 return DWARF_CB_OK;
401}
402
403/**
404 * die_find_realfunc - Search a non-inlined function at given address
405 * @cu_die: a CU DIE which including @addr
406 * @addr: target address
407 * @die_mem: a buffer for result DIE
408 *
409 * Search a non-inlined function DIE which includes @addr. Stores the
410 * DIE to @die_mem and returns it if found. Returns NULl if failed.
411 */
412Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
413 Dwarf_Die *die_mem)
414{
415 struct __addr_die_search_param ad;
416 ad.addr = addr;
417 ad.die_mem = die_mem;
418 /* dwarf_getscopes can't find subprogram. */
419 if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
420 return NULL;
421 else
422 return die_mem;
423}
424
425/* die_find callback for inline function search */
426static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
427{
428 Dwarf_Addr *addr = data;
429
430 if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
431 dwarf_haspc(die_mem, *addr))
432 return DIE_FIND_CB_END;
433
434 return DIE_FIND_CB_CONTINUE;
435}
436
437/**
438 * die_find_inlinefunc - Search an inlined function at given address
439 * @cu_die: a CU DIE which including @addr
440 * @addr: target address
441 * @die_mem: a buffer for result DIE
442 *
443 * Search an inlined function DIE which includes @addr. Stores the
444 * DIE to @die_mem and returns it if found. Returns NULl if failed.
445 * If several inlined functions are expanded recursively, this trace
446 * it and returns deepest one.
447 */
448Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
449 Dwarf_Die *die_mem)
450{
451 Dwarf_Die tmp_die;
452
453 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
454 if (!sp_die)
455 return NULL;
456
457 /* Inlined function could be recursive. Trace it until fail */
458 while (sp_die) {
459 memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
460 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
461 &tmp_die);
462 }
463
464 return die_mem;
465}
466
467struct __instance_walk_param {
468 void *addr;
469 int (*callback)(Dwarf_Die *, void *);
470 void *data;
471 int retval;
472};
473
474static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
475{
476 struct __instance_walk_param *iwp = data;
477 Dwarf_Attribute attr_mem;
478 Dwarf_Die origin_mem;
479 Dwarf_Attribute *attr;
480 Dwarf_Die *origin;
481 int tmp;
482
483 attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
484 if (attr == NULL)
485 return DIE_FIND_CB_CONTINUE;
486
487 origin = dwarf_formref_die(attr, &origin_mem);
488 if (origin == NULL || origin->addr != iwp->addr)
489 return DIE_FIND_CB_CONTINUE;
490
491 /* Ignore redundant instances */
492 if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
493 dwarf_decl_line(origin, &tmp);
494 if (die_get_call_lineno(inst) == tmp) {
495 tmp = die_get_decl_fileno(origin);
496 if (die_get_call_fileno(inst) == tmp)
497 return DIE_FIND_CB_CONTINUE;
498 }
499 }
500
501 iwp->retval = iwp->callback(inst, iwp->data);
502
503 return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
504}
505
506/**
507 * die_walk_instances - Walk on instances of given DIE
508 * @or_die: an abstract original DIE
509 * @callback: a callback function which is called with instance DIE
510 * @data: user data
511 *
512 * Walk on the instances of give @in_die. @in_die must be an inlined function
513 * declartion. This returns the return value of @callback if it returns
514 * non-zero value, or -ENOENT if there is no instance.
515 */
516int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
517 void *data)
518{
519 Dwarf_Die cu_die;
520 Dwarf_Die die_mem;
521 struct __instance_walk_param iwp = {
522 .addr = or_die->addr,
523 .callback = callback,
524 .data = data,
525 .retval = -ENOENT,
526 };
527
528 if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
529 return -ENOENT;
530
531 die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
532
533 return iwp.retval;
534}
535
536/* Line walker internal parameters */
537struct __line_walk_param {
538 bool recursive;
539 line_walk_callback_t callback;
540 void *data;
541 int retval;
542};
543
544static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
545{
546 struct __line_walk_param *lw = data;
547 Dwarf_Addr addr = 0;
548 const char *fname;
549 int lineno;
550
551 if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
552 fname = die_get_call_file(in_die);
553 lineno = die_get_call_lineno(in_die);
554 if (fname && lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
555 lw->retval = lw->callback(fname, lineno, addr, lw->data);
556 if (lw->retval != 0)
557 return DIE_FIND_CB_END;
558 }
559 }
560 if (!lw->recursive)
561 /* Don't need to search recursively */
562 return DIE_FIND_CB_SIBLING;
563
564 if (addr) {
565 fname = dwarf_decl_file(in_die);
566 if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
567 lw->retval = lw->callback(fname, lineno, addr, lw->data);
568 if (lw->retval != 0)
569 return DIE_FIND_CB_END;
570 }
571 }
572
573 /* Continue to search nested inlined function call-sites */
574 return DIE_FIND_CB_CONTINUE;
575}
576
577/* Walk on lines of blocks included in given DIE */
578static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
579 line_walk_callback_t callback, void *data)
580{
581 struct __line_walk_param lw = {
582 .recursive = recursive,
583 .callback = callback,
584 .data = data,
585 .retval = 0,
586 };
587 Dwarf_Die die_mem;
588 Dwarf_Addr addr;
589 const char *fname;
590 int lineno;
591
592 /* Handle function declaration line */
593 fname = dwarf_decl_file(sp_die);
594 if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
595 dwarf_entrypc(sp_die, &addr) == 0) {
596 lw.retval = callback(fname, lineno, addr, data);
597 if (lw.retval != 0)
598 goto done;
599 }
600 die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
601done:
602 return lw.retval;
603}
604
605static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
606{
607 struct __line_walk_param *lw = data;
608
609 lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
610 if (lw->retval != 0)
611 return DWARF_CB_ABORT;
612
613 return DWARF_CB_OK;
614}
615
616/**
617 * die_walk_lines - Walk on lines inside given DIE
618 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
619 * @callback: callback routine
620 * @data: user data
621 *
622 * Walk on all lines inside given @rt_die and call @callback on each line.
623 * If the @rt_die is a function, walk only on the lines inside the function,
624 * otherwise @rt_die must be a CU DIE.
625 * Note that this walks not only dwarf line list, but also function entries
626 * and inline call-site.
627 */
628int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
629{
630 Dwarf_Lines *lines;
631 Dwarf_Line *line;
632 Dwarf_Addr addr;
633 const char *fname;
634 int lineno, ret = 0;
635 Dwarf_Die die_mem, *cu_die;
636 size_t nlines, i;
637
638 /* Get the CU die */
639 if (dwarf_tag(rt_die) != DW_TAG_compile_unit)
640 cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
641 else
642 cu_die = rt_die;
643 if (!cu_die) {
644 pr_debug2("Failed to get CU from given DIE.\n");
645 return -EINVAL;
646 }
647
648 /* Get lines list in the CU */
649 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
650 pr_debug2("Failed to get source lines on this CU.\n");
651 return -ENOENT;
652 }
653 pr_debug2("Get %zd lines from this CU\n", nlines);
654
655 /* Walk on the lines on lines list */
656 for (i = 0; i < nlines; i++) {
657 line = dwarf_onesrcline(lines, i);
658 if (line == NULL ||
659 dwarf_lineno(line, &lineno) != 0 ||
660 dwarf_lineaddr(line, &addr) != 0) {
661 pr_debug2("Failed to get line info. "
662 "Possible error in debuginfo.\n");
663 continue;
664 }
665 /* Filter lines based on address */
666 if (rt_die != cu_die)
667 /*
668 * Address filtering
669 * The line is included in given function, and
670 * no inline block includes it.
671 */
672 if (!dwarf_haspc(rt_die, addr) ||
673 die_find_inlinefunc(rt_die, addr, &die_mem))
674 continue;
675 /* Get source line */
676 fname = dwarf_linesrc(line, NULL, NULL);
677
678 ret = callback(fname, lineno, addr, data);
679 if (ret != 0)
680 return ret;
681 }
682
683 /*
684 * Dwarf lines doesn't include function declarations and inlined
685 * subroutines. We have to check functions list or given function.
686 */
687 if (rt_die != cu_die)
688 /*
689 * Don't need walk functions recursively, because nested
690 * inlined functions don't have lines of the specified DIE.
691 */
692 ret = __die_walk_funclines(rt_die, false, callback, data);
693 else {
694 struct __line_walk_param param = {
695 .callback = callback,
696 .data = data,
697 .retval = 0,
698 };
699 dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
700 ret = param.retval;
701 }
702
703 return ret;
704}
705
706struct __find_variable_param {
707 const char *name;
708 Dwarf_Addr addr;
709};
710
711static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
712{
713 struct __find_variable_param *fvp = data;
714 int tag;
715
716 tag = dwarf_tag(die_mem);
717 if ((tag == DW_TAG_formal_parameter ||
718 tag == DW_TAG_variable) &&
719 die_compare_name(die_mem, fvp->name))
720 return DIE_FIND_CB_END;
721
722 if (dwarf_haspc(die_mem, fvp->addr))
723 return DIE_FIND_CB_CONTINUE;
724 else
725 return DIE_FIND_CB_SIBLING;
726}
727
728/**
729 * die_find_variable_at - Find a given name variable at given address
730 * @sp_die: a function DIE
731 * @name: variable name
732 * @addr: address
733 * @die_mem: a buffer for result DIE
734 *
735 * Find a variable DIE called @name at @addr in @sp_die.
736 */
737Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
738 Dwarf_Addr addr, Dwarf_Die *die_mem)
739{
740 struct __find_variable_param fvp = { .name = name, .addr = addr};
741
742 return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
743 die_mem);
744}
745
746static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
747{
748 const char *name = data;
749
750 if ((dwarf_tag(die_mem) == DW_TAG_member) &&
751 die_compare_name(die_mem, name))
752 return DIE_FIND_CB_END;
753
754 return DIE_FIND_CB_SIBLING;
755}
756
757/**
758 * die_find_member - Find a given name member in a data structure
759 * @st_die: a data structure type DIE
760 * @name: member name
761 * @die_mem: a buffer for result DIE
762 *
763 * Find a member DIE called @name in @st_die.
764 */
765Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
766 Dwarf_Die *die_mem)
767{
768 return die_find_child(st_die, __die_find_member_cb, (void *)name,
769 die_mem);
770}
771
772/**
773 * die_get_typename - Get the name of given variable DIE
774 * @vr_die: a variable DIE
775 * @buf: a buffer for result type name
776 * @len: a max-length of @buf
777 *
778 * Get the name of @vr_die and stores it to @buf. Return the actual length
779 * of type name if succeeded. Return -E2BIG if @len is not enough long, and
780 * Return -ENOENT if failed to find type name.
781 * Note that the result will stores typedef name if possible, and stores
782 * "*(function_type)" if the type is a function pointer.
783 */
784int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
785{
786 Dwarf_Die type;
787 int tag, ret, ret2;
788 const char *tmp = "";
789
790 if (__die_get_real_type(vr_die, &type) == NULL)
791 return -ENOENT;
792
793 tag = dwarf_tag(&type);
794 if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
795 tmp = "*";
796 else if (tag == DW_TAG_subroutine_type) {
797 /* Function pointer */
798 ret = snprintf(buf, len, "(function_type)");
799 return (ret >= len) ? -E2BIG : ret;
800 } else {
801 if (!dwarf_diename(&type))
802 return -ENOENT;
803 if (tag == DW_TAG_union_type)
804 tmp = "union ";
805 else if (tag == DW_TAG_structure_type)
806 tmp = "struct ";
807 /* Write a base name */
808 ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
809 return (ret >= len) ? -E2BIG : ret;
810 }
811 ret = die_get_typename(&type, buf, len);
812 if (ret > 0) {
813 ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
814 ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
815 }
816 return ret;
817}
818
819/**
820 * die_get_varname - Get the name and type of given variable DIE
821 * @vr_die: a variable DIE
822 * @buf: a buffer for type and variable name
823 * @len: the max-length of @buf
824 *
825 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
826 */
827int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
828{
829 int ret, ret2;
830
831 ret = die_get_typename(vr_die, buf, len);
832 if (ret < 0) {
833 pr_debug("Failed to get type, make it unknown.\n");
834 ret = snprintf(buf, len, "(unknown_type)");
835 }
836 if (ret > 0) {
837 ret2 = snprintf(buf + ret, len - ret, "\t%s",
838 dwarf_diename(vr_die));
839 ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
840 }
841 return ret;
842}
843
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * dwarf-aux.c : libdw auxiliary interfaces
4 */
5
6#include <errno.h>
7#include <inttypes.h>
8#include <stdbool.h>
9#include <stdlib.h>
10#include "debug.h"
11#include "dwarf-aux.h"
12#include "strbuf.h"
13#include "string2.h"
14
15/**
16 * cu_find_realpath - Find the realpath of the target file
17 * @cu_die: A DIE(dwarf information entry) of CU(compilation Unit)
18 * @fname: The tail filename of the target file
19 *
20 * Find the real(long) path of @fname in @cu_die.
21 */
22const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
23{
24 Dwarf_Files *files;
25 size_t nfiles, i;
26 const char *src = NULL;
27 int ret;
28
29 if (!fname)
30 return NULL;
31
32 ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
33 if (ret != 0)
34 return NULL;
35
36 for (i = 0; i < nfiles; i++) {
37 src = dwarf_filesrc(files, i, NULL, NULL);
38 if (strtailcmp(src, fname) == 0)
39 break;
40 }
41 if (i == nfiles)
42 return NULL;
43 return src;
44}
45
46/**
47 * cu_get_comp_dir - Get the path of compilation directory
48 * @cu_die: a CU DIE
49 *
50 * Get the path of compilation directory of given @cu_die.
51 * Since this depends on DW_AT_comp_dir, older gcc will not
52 * embedded it. In that case, this returns NULL.
53 */
54const char *cu_get_comp_dir(Dwarf_Die *cu_die)
55{
56 Dwarf_Attribute attr;
57 if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
58 return NULL;
59 return dwarf_formstring(&attr);
60}
61
62/**
63 * cu_find_lineinfo - Get a line number and file name for given address
64 * @cu_die: a CU DIE
65 * @addr: An address
66 * @fname: a pointer which returns the file name string
67 * @lineno: a pointer which returns the line number
68 *
69 * Find a line number and file name for @addr in @cu_die.
70 */
71int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr,
72 const char **fname, int *lineno)
73{
74 Dwarf_Line *line;
75 Dwarf_Addr laddr;
76
77 line = dwarf_getsrc_die(cu_die, (Dwarf_Addr)addr);
78 if (line && dwarf_lineaddr(line, &laddr) == 0 &&
79 addr == (unsigned long)laddr && dwarf_lineno(line, lineno) == 0) {
80 *fname = dwarf_linesrc(line, NULL, NULL);
81 if (!*fname)
82 /* line number is useless without filename */
83 *lineno = 0;
84 }
85
86 return *lineno ?: -ENOENT;
87}
88
89static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
90
91/**
92 * cu_walk_functions_at - Walk on function DIEs at given address
93 * @cu_die: A CU DIE
94 * @addr: An address
95 * @callback: A callback which called with found DIEs
96 * @data: A user data
97 *
98 * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
99 * should be subprogram or inlined-subroutines.
100 */
101int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
102 int (*callback)(Dwarf_Die *, void *), void *data)
103{
104 Dwarf_Die die_mem;
105 Dwarf_Die *sc_die;
106 int ret = -ENOENT;
107
108 /* Inlined function could be recursive. Trace it until fail */
109 for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
110 sc_die != NULL;
111 sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
112 &die_mem)) {
113 ret = callback(sc_die, data);
114 if (ret)
115 break;
116 }
117
118 return ret;
119
120}
121
122/**
123 * die_get_linkage_name - Get the linkage name of the object
124 * @dw_die: A DIE of the object
125 *
126 * Get the linkage name attiribute of given @dw_die.
127 * For C++ binary, the linkage name will be the mangled symbol.
128 */
129const char *die_get_linkage_name(Dwarf_Die *dw_die)
130{
131 Dwarf_Attribute attr;
132
133 if (dwarf_attr_integrate(dw_die, DW_AT_linkage_name, &attr) == NULL)
134 return NULL;
135 return dwarf_formstring(&attr);
136}
137
138/**
139 * die_compare_name - Compare diename and tname
140 * @dw_die: a DIE
141 * @tname: a string of target name
142 *
143 * Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
144 */
145bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
146{
147 const char *name;
148
149 name = dwarf_diename(dw_die);
150 return name ? (strcmp(tname, name) == 0) : false;
151}
152
153/**
154 * die_match_name - Match diename/linkage name and glob
155 * @dw_die: a DIE
156 * @glob: a string of target glob pattern
157 *
158 * Glob matching the name of @dw_die and @glob. Return false if matching fail.
159 * This also match linkage name.
160 */
161bool die_match_name(Dwarf_Die *dw_die, const char *glob)
162{
163 const char *name;
164
165 name = dwarf_diename(dw_die);
166 if (name && strglobmatch(name, glob))
167 return true;
168 /* fall back to check linkage name */
169 name = die_get_linkage_name(dw_die);
170 if (name && strglobmatch(name, glob))
171 return true;
172
173 return false;
174}
175
176/**
177 * die_get_call_lineno - Get callsite line number of inline-function instance
178 * @in_die: a DIE of an inlined function instance
179 *
180 * Get call-site line number of @in_die. This means from where the inline
181 * function is called.
182 */
183int die_get_call_lineno(Dwarf_Die *in_die)
184{
185 Dwarf_Attribute attr;
186 Dwarf_Word ret;
187
188 if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
189 return -ENOENT;
190
191 dwarf_formudata(&attr, &ret);
192 return (int)ret;
193}
194
195/**
196 * die_get_type - Get type DIE
197 * @vr_die: a DIE of a variable
198 * @die_mem: where to store a type DIE
199 *
200 * Get a DIE of the type of given variable (@vr_die), and store
201 * it to die_mem. Return NULL if fails to get a type DIE.
202 */
203Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
204{
205 Dwarf_Attribute attr;
206
207 if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
208 dwarf_formref_die(&attr, die_mem))
209 return die_mem;
210 else
211 return NULL;
212}
213
214/* Get a type die, but skip qualifiers */
215static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
216{
217 int tag;
218
219 do {
220 vr_die = die_get_type(vr_die, die_mem);
221 if (!vr_die)
222 break;
223 tag = dwarf_tag(vr_die);
224 } while (tag == DW_TAG_const_type ||
225 tag == DW_TAG_restrict_type ||
226 tag == DW_TAG_volatile_type ||
227 tag == DW_TAG_shared_type);
228
229 return vr_die;
230}
231
232/**
233 * die_get_real_type - Get a type die, but skip qualifiers and typedef
234 * @vr_die: a DIE of a variable
235 * @die_mem: where to store a type DIE
236 *
237 * Get a DIE of the type of given variable (@vr_die), and store
238 * it to die_mem. Return NULL if fails to get a type DIE.
239 * If the type is qualifiers (e.g. const) or typedef, this skips it
240 * and tries to find real type (structure or basic types, e.g. int).
241 */
242Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
243{
244 do {
245 vr_die = __die_get_real_type(vr_die, die_mem);
246 } while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
247
248 return vr_die;
249}
250
251/* Get attribute and translate it as a udata */
252static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
253 Dwarf_Word *result)
254{
255 Dwarf_Attribute attr;
256
257 if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
258 dwarf_formudata(&attr, result) != 0)
259 return -ENOENT;
260
261 return 0;
262}
263
264/* Get attribute and translate it as a sdata */
265static int die_get_attr_sdata(Dwarf_Die *tp_die, unsigned int attr_name,
266 Dwarf_Sword *result)
267{
268 Dwarf_Attribute attr;
269
270 if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
271 dwarf_formsdata(&attr, result) != 0)
272 return -ENOENT;
273
274 return 0;
275}
276
277/**
278 * die_is_signed_type - Check whether a type DIE is signed or not
279 * @tp_die: a DIE of a type
280 *
281 * Get the encoding of @tp_die and return true if the encoding
282 * is signed.
283 */
284bool die_is_signed_type(Dwarf_Die *tp_die)
285{
286 Dwarf_Word ret;
287
288 if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
289 return false;
290
291 return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
292 ret == DW_ATE_signed_fixed);
293}
294
295/**
296 * die_is_func_def - Ensure that this DIE is a subprogram and definition
297 * @dw_die: a DIE
298 *
299 * Ensure that this DIE is a subprogram and NOT a declaration. This
300 * returns true if @dw_die is a function definition.
301 **/
302bool die_is_func_def(Dwarf_Die *dw_die)
303{
304 Dwarf_Attribute attr;
305
306 return (dwarf_tag(dw_die) == DW_TAG_subprogram &&
307 dwarf_attr(dw_die, DW_AT_declaration, &attr) == NULL);
308}
309
310/**
311 * die_is_func_instance - Ensure that this DIE is an instance of a subprogram
312 * @dw_die: a DIE
313 *
314 * Ensure that this DIE is an instance (which has an entry address).
315 * This returns true if @dw_die is a function instance. If not, you need to
316 * call die_walk_instances() to find actual instances.
317 **/
318bool die_is_func_instance(Dwarf_Die *dw_die)
319{
320 Dwarf_Addr tmp;
321
322 /* Actually gcc optimizes non-inline as like as inlined */
323 return !dwarf_func_inline(dw_die) && dwarf_entrypc(dw_die, &tmp) == 0;
324}
325/**
326 * die_get_data_member_location - Get the data-member offset
327 * @mb_die: a DIE of a member of a data structure
328 * @offs: The offset of the member in the data structure
329 *
330 * Get the offset of @mb_die in the data structure including @mb_die, and
331 * stores result offset to @offs. If any error occurs this returns errno.
332 */
333int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
334{
335 Dwarf_Attribute attr;
336 Dwarf_Op *expr;
337 size_t nexpr;
338 int ret;
339
340 if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
341 return -ENOENT;
342
343 if (dwarf_formudata(&attr, offs) != 0) {
344 /* DW_AT_data_member_location should be DW_OP_plus_uconst */
345 ret = dwarf_getlocation(&attr, &expr, &nexpr);
346 if (ret < 0 || nexpr == 0)
347 return -ENOENT;
348
349 if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
350 pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
351 expr[0].atom, nexpr);
352 return -ENOTSUP;
353 }
354 *offs = (Dwarf_Word)expr[0].number;
355 }
356 return 0;
357}
358
359/* Get the call file index number in CU DIE */
360static int die_get_call_fileno(Dwarf_Die *in_die)
361{
362 Dwarf_Sword idx;
363
364 if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0)
365 return (int)idx;
366 else
367 return -ENOENT;
368}
369
370/* Get the declared file index number in CU DIE */
371static int die_get_decl_fileno(Dwarf_Die *pdie)
372{
373 Dwarf_Sword idx;
374
375 if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0)
376 return (int)idx;
377 else
378 return -ENOENT;
379}
380
381/**
382 * die_get_call_file - Get callsite file name of inlined function instance
383 * @in_die: a DIE of an inlined function instance
384 *
385 * Get call-site file name of @in_die. This means from which file the inline
386 * function is called.
387 */
388const char *die_get_call_file(Dwarf_Die *in_die)
389{
390 Dwarf_Die cu_die;
391 Dwarf_Files *files;
392 int idx;
393
394 idx = die_get_call_fileno(in_die);
395 if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
396 dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
397 return NULL;
398
399 return dwarf_filesrc(files, idx, NULL, NULL);
400}
401
402
403/**
404 * die_find_child - Generic DIE search function in DIE tree
405 * @rt_die: a root DIE
406 * @callback: a callback function
407 * @data: a user data passed to the callback function
408 * @die_mem: a buffer for result DIE
409 *
410 * Trace DIE tree from @rt_die and call @callback for each child DIE.
411 * If @callback returns DIE_FIND_CB_END, this stores the DIE into
412 * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
413 * this continues to trace the tree. Optionally, @callback can return
414 * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
415 * the children and trace only the siblings respectively.
416 * Returns NULL if @callback can't find any appropriate DIE.
417 */
418Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
419 int (*callback)(Dwarf_Die *, void *),
420 void *data, Dwarf_Die *die_mem)
421{
422 Dwarf_Die child_die;
423 int ret;
424
425 ret = dwarf_child(rt_die, die_mem);
426 if (ret != 0)
427 return NULL;
428
429 do {
430 ret = callback(die_mem, data);
431 if (ret == DIE_FIND_CB_END)
432 return die_mem;
433
434 if ((ret & DIE_FIND_CB_CHILD) &&
435 die_find_child(die_mem, callback, data, &child_die)) {
436 memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
437 return die_mem;
438 }
439 } while ((ret & DIE_FIND_CB_SIBLING) &&
440 dwarf_siblingof(die_mem, die_mem) == 0);
441
442 return NULL;
443}
444
445struct __addr_die_search_param {
446 Dwarf_Addr addr;
447 Dwarf_Die *die_mem;
448};
449
450static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
451{
452 struct __addr_die_search_param *ad = data;
453 Dwarf_Addr addr = 0;
454
455 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
456 !dwarf_highpc(fn_die, &addr) &&
457 addr == ad->addr) {
458 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
459 return DWARF_CB_ABORT;
460 }
461 return DWARF_CB_OK;
462}
463
464/**
465 * die_find_tailfunc - Search for a non-inlined function with tail call at
466 * given address
467 * @cu_die: a CU DIE which including @addr
468 * @addr: target address
469 * @die_mem: a buffer for result DIE
470 *
471 * Search for a non-inlined function DIE with tail call at @addr. Stores the
472 * DIE to @die_mem and returns it if found. Returns NULL if failed.
473 */
474Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
475 Dwarf_Die *die_mem)
476{
477 struct __addr_die_search_param ad;
478 ad.addr = addr;
479 ad.die_mem = die_mem;
480 /* dwarf_getscopes can't find subprogram. */
481 if (!dwarf_getfuncs(cu_die, __die_search_func_tail_cb, &ad, 0))
482 return NULL;
483 else
484 return die_mem;
485}
486
487/* die_find callback for non-inlined function search */
488static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
489{
490 struct __addr_die_search_param *ad = data;
491
492 /*
493 * Since a declaration entry doesn't has given pc, this always returns
494 * function definition entry.
495 */
496 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
497 dwarf_haspc(fn_die, ad->addr)) {
498 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
499 return DWARF_CB_ABORT;
500 }
501 return DWARF_CB_OK;
502}
503
504/**
505 * die_find_realfunc - Search a non-inlined function at given address
506 * @cu_die: a CU DIE which including @addr
507 * @addr: target address
508 * @die_mem: a buffer for result DIE
509 *
510 * Search a non-inlined function DIE which includes @addr. Stores the
511 * DIE to @die_mem and returns it if found. Returns NULL if failed.
512 */
513Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
514 Dwarf_Die *die_mem)
515{
516 struct __addr_die_search_param ad;
517 ad.addr = addr;
518 ad.die_mem = die_mem;
519 /* dwarf_getscopes can't find subprogram. */
520 if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
521 return NULL;
522 else
523 return die_mem;
524}
525
526/* die_find callback for inline function search */
527static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
528{
529 Dwarf_Addr *addr = data;
530
531 if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
532 dwarf_haspc(die_mem, *addr))
533 return DIE_FIND_CB_END;
534
535 return DIE_FIND_CB_CONTINUE;
536}
537
538/**
539 * die_find_top_inlinefunc - Search the top inlined function at given address
540 * @sp_die: a subprogram DIE which including @addr
541 * @addr: target address
542 * @die_mem: a buffer for result DIE
543 *
544 * Search an inlined function DIE which includes @addr. Stores the
545 * DIE to @die_mem and returns it if found. Returns NULL if failed.
546 * Even if several inlined functions are expanded recursively, this
547 * doesn't trace it down, and returns the topmost one.
548 */
549Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
550 Dwarf_Die *die_mem)
551{
552 return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
553}
554
555/**
556 * die_find_inlinefunc - Search an inlined function at given address
557 * @sp_die: a subprogram DIE which including @addr
558 * @addr: target address
559 * @die_mem: a buffer for result DIE
560 *
561 * Search an inlined function DIE which includes @addr. Stores the
562 * DIE to @die_mem and returns it if found. Returns NULL if failed.
563 * If several inlined functions are expanded recursively, this trace
564 * it down and returns deepest one.
565 */
566Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
567 Dwarf_Die *die_mem)
568{
569 Dwarf_Die tmp_die;
570
571 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
572 if (!sp_die)
573 return NULL;
574
575 /* Inlined function could be recursive. Trace it until fail */
576 while (sp_die) {
577 memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
578 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
579 &tmp_die);
580 }
581
582 return die_mem;
583}
584
585struct __instance_walk_param {
586 void *addr;
587 int (*callback)(Dwarf_Die *, void *);
588 void *data;
589 int retval;
590};
591
592static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
593{
594 struct __instance_walk_param *iwp = data;
595 Dwarf_Attribute attr_mem;
596 Dwarf_Die origin_mem;
597 Dwarf_Attribute *attr;
598 Dwarf_Die *origin;
599 int tmp;
600
601 attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
602 if (attr == NULL)
603 return DIE_FIND_CB_CONTINUE;
604
605 origin = dwarf_formref_die(attr, &origin_mem);
606 if (origin == NULL || origin->addr != iwp->addr)
607 return DIE_FIND_CB_CONTINUE;
608
609 /* Ignore redundant instances */
610 if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
611 dwarf_decl_line(origin, &tmp);
612 if (die_get_call_lineno(inst) == tmp) {
613 tmp = die_get_decl_fileno(origin);
614 if (die_get_call_fileno(inst) == tmp)
615 return DIE_FIND_CB_CONTINUE;
616 }
617 }
618
619 iwp->retval = iwp->callback(inst, iwp->data);
620
621 return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
622}
623
624/**
625 * die_walk_instances - Walk on instances of given DIE
626 * @or_die: an abstract original DIE
627 * @callback: a callback function which is called with instance DIE
628 * @data: user data
629 *
630 * Walk on the instances of give @in_die. @in_die must be an inlined function
631 * declartion. This returns the return value of @callback if it returns
632 * non-zero value, or -ENOENT if there is no instance.
633 */
634int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
635 void *data)
636{
637 Dwarf_Die cu_die;
638 Dwarf_Die die_mem;
639 struct __instance_walk_param iwp = {
640 .addr = or_die->addr,
641 .callback = callback,
642 .data = data,
643 .retval = -ENOENT,
644 };
645
646 if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
647 return -ENOENT;
648
649 die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
650
651 return iwp.retval;
652}
653
654/* Line walker internal parameters */
655struct __line_walk_param {
656 bool recursive;
657 line_walk_callback_t callback;
658 void *data;
659 int retval;
660};
661
662static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
663{
664 struct __line_walk_param *lw = data;
665 Dwarf_Addr addr = 0;
666 const char *fname;
667 int lineno;
668
669 if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
670 fname = die_get_call_file(in_die);
671 lineno = die_get_call_lineno(in_die);
672 if (fname && lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
673 lw->retval = lw->callback(fname, lineno, addr, lw->data);
674 if (lw->retval != 0)
675 return DIE_FIND_CB_END;
676 }
677 }
678 if (!lw->recursive)
679 /* Don't need to search recursively */
680 return DIE_FIND_CB_SIBLING;
681
682 if (addr) {
683 fname = dwarf_decl_file(in_die);
684 if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
685 lw->retval = lw->callback(fname, lineno, addr, lw->data);
686 if (lw->retval != 0)
687 return DIE_FIND_CB_END;
688 }
689 }
690
691 /* Continue to search nested inlined function call-sites */
692 return DIE_FIND_CB_CONTINUE;
693}
694
695/* Walk on lines of blocks included in given DIE */
696static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
697 line_walk_callback_t callback, void *data)
698{
699 struct __line_walk_param lw = {
700 .recursive = recursive,
701 .callback = callback,
702 .data = data,
703 .retval = 0,
704 };
705 Dwarf_Die die_mem;
706 Dwarf_Addr addr;
707 const char *fname;
708 int lineno;
709
710 /* Handle function declaration line */
711 fname = dwarf_decl_file(sp_die);
712 if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
713 dwarf_entrypc(sp_die, &addr) == 0) {
714 lw.retval = callback(fname, lineno, addr, data);
715 if (lw.retval != 0)
716 goto done;
717 }
718 die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
719done:
720 return lw.retval;
721}
722
723static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
724{
725 struct __line_walk_param *lw = data;
726
727 lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
728 if (lw->retval != 0)
729 return DWARF_CB_ABORT;
730
731 return DWARF_CB_OK;
732}
733
734/**
735 * die_walk_lines - Walk on lines inside given DIE
736 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
737 * @callback: callback routine
738 * @data: user data
739 *
740 * Walk on all lines inside given @rt_die and call @callback on each line.
741 * If the @rt_die is a function, walk only on the lines inside the function,
742 * otherwise @rt_die must be a CU DIE.
743 * Note that this walks not only dwarf line list, but also function entries
744 * and inline call-site.
745 */
746int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
747{
748 Dwarf_Lines *lines;
749 Dwarf_Line *line;
750 Dwarf_Addr addr;
751 const char *fname, *decf = NULL;
752 int lineno, ret = 0;
753 int decl = 0, inl;
754 Dwarf_Die die_mem, *cu_die;
755 size_t nlines, i;
756
757 /* Get the CU die */
758 if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
759 cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
760 dwarf_decl_line(rt_die, &decl);
761 decf = dwarf_decl_file(rt_die);
762 } else
763 cu_die = rt_die;
764 if (!cu_die) {
765 pr_debug2("Failed to get CU from given DIE.\n");
766 return -EINVAL;
767 }
768
769 /* Get lines list in the CU */
770 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
771 pr_debug2("Failed to get source lines on this CU.\n");
772 return -ENOENT;
773 }
774 pr_debug2("Get %zd lines from this CU\n", nlines);
775
776 /* Walk on the lines on lines list */
777 for (i = 0; i < nlines; i++) {
778 line = dwarf_onesrcline(lines, i);
779 if (line == NULL ||
780 dwarf_lineno(line, &lineno) != 0 ||
781 dwarf_lineaddr(line, &addr) != 0) {
782 pr_debug2("Failed to get line info. "
783 "Possible error in debuginfo.\n");
784 continue;
785 }
786 /* Filter lines based on address */
787 if (rt_die != cu_die) {
788 /*
789 * Address filtering
790 * The line is included in given function, and
791 * no inline block includes it.
792 */
793 if (!dwarf_haspc(rt_die, addr))
794 continue;
795 if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
796 dwarf_decl_line(&die_mem, &inl);
797 if (inl != decl ||
798 decf != dwarf_decl_file(&die_mem))
799 continue;
800 }
801 }
802 /* Get source line */
803 fname = dwarf_linesrc(line, NULL, NULL);
804
805 ret = callback(fname, lineno, addr, data);
806 if (ret != 0)
807 return ret;
808 }
809
810 /*
811 * Dwarf lines doesn't include function declarations and inlined
812 * subroutines. We have to check functions list or given function.
813 */
814 if (rt_die != cu_die)
815 /*
816 * Don't need walk functions recursively, because nested
817 * inlined functions don't have lines of the specified DIE.
818 */
819 ret = __die_walk_funclines(rt_die, false, callback, data);
820 else {
821 struct __line_walk_param param = {
822 .callback = callback,
823 .data = data,
824 .retval = 0,
825 };
826 dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
827 ret = param.retval;
828 }
829
830 return ret;
831}
832
833struct __find_variable_param {
834 const char *name;
835 Dwarf_Addr addr;
836};
837
838static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
839{
840 struct __find_variable_param *fvp = data;
841 Dwarf_Attribute attr;
842 int tag;
843
844 tag = dwarf_tag(die_mem);
845 if ((tag == DW_TAG_formal_parameter ||
846 tag == DW_TAG_variable) &&
847 die_compare_name(die_mem, fvp->name) &&
848 /* Does the DIE have location information or external instance? */
849 (dwarf_attr(die_mem, DW_AT_external, &attr) ||
850 dwarf_attr(die_mem, DW_AT_location, &attr)))
851 return DIE_FIND_CB_END;
852 if (dwarf_haspc(die_mem, fvp->addr))
853 return DIE_FIND_CB_CONTINUE;
854 else
855 return DIE_FIND_CB_SIBLING;
856}
857
858/**
859 * die_find_variable_at - Find a given name variable at given address
860 * @sp_die: a function DIE
861 * @name: variable name
862 * @addr: address
863 * @die_mem: a buffer for result DIE
864 *
865 * Find a variable DIE called @name at @addr in @sp_die.
866 */
867Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
868 Dwarf_Addr addr, Dwarf_Die *die_mem)
869{
870 struct __find_variable_param fvp = { .name = name, .addr = addr};
871
872 return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
873 die_mem);
874}
875
876static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
877{
878 const char *name = data;
879
880 if (dwarf_tag(die_mem) == DW_TAG_member) {
881 if (die_compare_name(die_mem, name))
882 return DIE_FIND_CB_END;
883 else if (!dwarf_diename(die_mem)) { /* Unnamed structure */
884 Dwarf_Die type_die, tmp_die;
885 if (die_get_type(die_mem, &type_die) &&
886 die_find_member(&type_die, name, &tmp_die))
887 return DIE_FIND_CB_END;
888 }
889 }
890 return DIE_FIND_CB_SIBLING;
891}
892
893/**
894 * die_find_member - Find a given name member in a data structure
895 * @st_die: a data structure type DIE
896 * @name: member name
897 * @die_mem: a buffer for result DIE
898 *
899 * Find a member DIE called @name in @st_die.
900 */
901Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
902 Dwarf_Die *die_mem)
903{
904 return die_find_child(st_die, __die_find_member_cb, (void *)name,
905 die_mem);
906}
907
908/**
909 * die_get_typename - Get the name of given variable DIE
910 * @vr_die: a variable DIE
911 * @buf: a strbuf for result type name
912 *
913 * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
914 * and Return -ENOENT if failed to find type name.
915 * Note that the result will stores typedef name if possible, and stores
916 * "*(function_type)" if the type is a function pointer.
917 */
918int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
919{
920 Dwarf_Die type;
921 int tag, ret;
922 const char *tmp = "";
923
924 if (__die_get_real_type(vr_die, &type) == NULL)
925 return -ENOENT;
926
927 tag = dwarf_tag(&type);
928 if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
929 tmp = "*";
930 else if (tag == DW_TAG_subroutine_type) {
931 /* Function pointer */
932 return strbuf_add(buf, "(function_type)", 15);
933 } else {
934 if (!dwarf_diename(&type))
935 return -ENOENT;
936 if (tag == DW_TAG_union_type)
937 tmp = "union ";
938 else if (tag == DW_TAG_structure_type)
939 tmp = "struct ";
940 else if (tag == DW_TAG_enumeration_type)
941 tmp = "enum ";
942 /* Write a base name */
943 return strbuf_addf(buf, "%s%s", tmp, dwarf_diename(&type));
944 }
945 ret = die_get_typename(&type, buf);
946 return ret ? ret : strbuf_addstr(buf, tmp);
947}
948
949/**
950 * die_get_varname - Get the name and type of given variable DIE
951 * @vr_die: a variable DIE
952 * @buf: a strbuf for type and variable name
953 *
954 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
955 */
956int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
957{
958 int ret;
959
960 ret = die_get_typename(vr_die, buf);
961 if (ret < 0) {
962 pr_debug("Failed to get type, make it unknown.\n");
963 ret = strbuf_add(buf, " (unknown_type)", 14);
964 }
965
966 return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
967}
968
969#ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT
970/**
971 * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
972 * @sp_die: a subprogram DIE
973 * @vr_die: a variable DIE
974 * @buf: a strbuf for variable byte offset range
975 *
976 * Get the innermost scope range of @vr_die and stores it in @buf as
977 * "@<function_name+[NN-NN,NN-NN]>".
978 */
979static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
980 struct strbuf *buf)
981{
982 Dwarf_Die *scopes;
983 int count;
984 size_t offset = 0;
985 Dwarf_Addr base;
986 Dwarf_Addr start, end;
987 Dwarf_Addr entry;
988 int ret;
989 bool first = true;
990 const char *name;
991
992 ret = dwarf_entrypc(sp_die, &entry);
993 if (ret)
994 return ret;
995
996 name = dwarf_diename(sp_die);
997 if (!name)
998 return -ENOENT;
999
1000 count = dwarf_getscopes_die(vr_die, &scopes);
1001
1002 /* (*SCOPES)[1] is the DIE for the scope containing that scope */
1003 if (count <= 1) {
1004 ret = -EINVAL;
1005 goto out;
1006 }
1007
1008 while ((offset = dwarf_ranges(&scopes[1], offset, &base,
1009 &start, &end)) > 0) {
1010 start -= entry;
1011 end -= entry;
1012
1013 if (first) {
1014 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1015 name, start, end);
1016 first = false;
1017 } else {
1018 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1019 start, end);
1020 }
1021 if (ret < 0)
1022 goto out;
1023 }
1024
1025 if (!first)
1026 ret = strbuf_add(buf, "]>", 2);
1027
1028out:
1029 free(scopes);
1030 return ret;
1031}
1032
1033/**
1034 * die_get_var_range - Get byte offset range of given variable DIE
1035 * @sp_die: a subprogram DIE
1036 * @vr_die: a variable DIE
1037 * @buf: a strbuf for type and variable name and byte offset range
1038 *
1039 * Get the byte offset range of @vr_die and stores it in @buf as
1040 * "@<function_name+[NN-NN,NN-NN]>".
1041 */
1042int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
1043{
1044 int ret = 0;
1045 Dwarf_Addr base;
1046 Dwarf_Addr start, end;
1047 Dwarf_Addr entry;
1048 Dwarf_Op *op;
1049 size_t nops;
1050 size_t offset = 0;
1051 Dwarf_Attribute attr;
1052 bool first = true;
1053 const char *name;
1054
1055 ret = dwarf_entrypc(sp_die, &entry);
1056 if (ret)
1057 return ret;
1058
1059 name = dwarf_diename(sp_die);
1060 if (!name)
1061 return -ENOENT;
1062
1063 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
1064 return -EINVAL;
1065
1066 while ((offset = dwarf_getlocations(&attr, offset, &base,
1067 &start, &end, &op, &nops)) > 0) {
1068 if (start == 0) {
1069 /* Single Location Descriptions */
1070 ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
1071 goto out;
1072 }
1073
1074 /* Location Lists */
1075 start -= entry;
1076 end -= entry;
1077 if (first) {
1078 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1079 name, start, end);
1080 first = false;
1081 } else {
1082 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1083 start, end);
1084 }
1085 if (ret < 0)
1086 goto out;
1087 }
1088
1089 if (!first)
1090 ret = strbuf_add(buf, "]>", 2);
1091out:
1092 return ret;
1093}
1094#else
1095int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
1096 Dwarf_Die *vr_die __maybe_unused,
1097 struct strbuf *buf __maybe_unused)
1098{
1099 return -ENOTSUP;
1100}
1101#endif
1102
1103/*
1104 * die_has_loclist - Check if DW_AT_location of @vr_die is a location list
1105 * @vr_die: a variable DIE
1106 */
1107static bool die_has_loclist(Dwarf_Die *vr_die)
1108{
1109 Dwarf_Attribute loc;
1110 int tag = dwarf_tag(vr_die);
1111
1112 if (tag != DW_TAG_formal_parameter &&
1113 tag != DW_TAG_variable)
1114 return false;
1115
1116 return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
1117 dwarf_whatform(&loc) == DW_FORM_sec_offset);
1118}
1119
1120/*
1121 * die_is_optimized_target - Check if target program is compiled with
1122 * optimization
1123 * @cu_die: a CU DIE
1124 *
1125 * For any object in given CU whose DW_AT_location is a location list,
1126 * target program is compiled with optimization. This is applicable to
1127 * clang as well.
1128 */
1129bool die_is_optimized_target(Dwarf_Die *cu_die)
1130{
1131 Dwarf_Die tmp_die;
1132
1133 if (die_has_loclist(cu_die))
1134 return true;
1135
1136 if (!dwarf_child(cu_die, &tmp_die) &&
1137 die_is_optimized_target(&tmp_die))
1138 return true;
1139
1140 if (!dwarf_siblingof(cu_die, &tmp_die) &&
1141 die_is_optimized_target(&tmp_die))
1142 return true;
1143
1144 return false;
1145}
1146
1147/*
1148 * die_search_idx - Search index of given line address
1149 * @lines: Line records of single CU
1150 * @nr_lines: Number of @lines
1151 * @addr: address we are looking for
1152 * @idx: index to be set by this function (return value)
1153 *
1154 * Search for @addr by looping over every lines of CU. If address
1155 * matches, set index of that line in @idx. Note that single source
1156 * line can have multiple line records. i.e. single source line can
1157 * have multiple index.
1158 */
1159static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
1160 Dwarf_Addr addr, unsigned long *idx)
1161{
1162 unsigned long i;
1163 Dwarf_Addr tmp;
1164
1165 for (i = 0; i < nr_lines; i++) {
1166 if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
1167 return false;
1168
1169 if (tmp == addr) {
1170 *idx = i;
1171 return true;
1172 }
1173 }
1174 return false;
1175}
1176
1177/*
1178 * die_get_postprologue_addr - Search next address after function prologue
1179 * @entrypc_idx: entrypc index
1180 * @lines: Line records of single CU
1181 * @nr_lines: Number of @lines
1182 * @hignpc: high PC address of function
1183 * @postprologue_addr: Next address after function prologue (return value)
1184 *
1185 * Look for prologue-end marker. If there is no explicit marker, return
1186 * address of next line record or next source line.
1187 */
1188static bool die_get_postprologue_addr(unsigned long entrypc_idx,
1189 Dwarf_Lines *lines,
1190 unsigned long nr_lines,
1191 Dwarf_Addr highpc,
1192 Dwarf_Addr *postprologue_addr)
1193{
1194 unsigned long i;
1195 int entrypc_lno, lno;
1196 Dwarf_Line *line;
1197 Dwarf_Addr addr;
1198 bool p_end;
1199
1200 /* entrypc_lno is actual source line number */
1201 line = dwarf_onesrcline(lines, entrypc_idx);
1202 if (dwarf_lineno(line, &entrypc_lno))
1203 return false;
1204
1205 for (i = entrypc_idx; i < nr_lines; i++) {
1206 line = dwarf_onesrcline(lines, i);
1207
1208 if (dwarf_lineaddr(line, &addr) ||
1209 dwarf_lineno(line, &lno) ||
1210 dwarf_lineprologueend(line, &p_end))
1211 return false;
1212
1213 /* highpc is exclusive. [entrypc,highpc) */
1214 if (addr >= highpc)
1215 break;
1216
1217 /* clang supports prologue-end marker */
1218 if (p_end)
1219 break;
1220
1221 /* Actual next line in source */
1222 if (lno != entrypc_lno)
1223 break;
1224
1225 /*
1226 * Single source line can have multiple line records.
1227 * For Example,
1228 * void foo() { printf("hello\n"); }
1229 * contains two line records. One points to declaration and
1230 * other points to printf() line. Variable 'lno' won't get
1231 * incremented in this case but 'i' will.
1232 */
1233 if (i != entrypc_idx)
1234 break;
1235 }
1236
1237 dwarf_lineaddr(line, postprologue_addr);
1238 if (*postprologue_addr >= highpc)
1239 dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
1240 postprologue_addr);
1241
1242 return true;
1243}
1244
1245/*
1246 * die_skip_prologue - Use next address after prologue as probe location
1247 * @sp_die: a subprogram DIE
1248 * @cu_die: a CU DIE
1249 * @entrypc: entrypc of the function
1250 *
1251 * Function prologue prepares stack and registers before executing function
1252 * logic. When target program is compiled without optimization, function
1253 * parameter information is only valid after prologue. When we probe entrypc
1254 * of the function, and try to record function parameter, it contains
1255 * garbage value.
1256 */
1257void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
1258 Dwarf_Addr *entrypc)
1259{
1260 size_t nr_lines = 0;
1261 unsigned long entrypc_idx = 0;
1262 Dwarf_Lines *lines = NULL;
1263 Dwarf_Addr postprologue_addr;
1264 Dwarf_Addr highpc;
1265
1266 if (dwarf_highpc(sp_die, &highpc))
1267 return;
1268
1269 if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
1270 return;
1271
1272 if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
1273 return;
1274
1275 if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
1276 highpc, &postprologue_addr))
1277 return;
1278
1279 *entrypc = postprologue_addr;
1280}