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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}
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 "dwarf-regs.h"
13#include "strbuf.h"
14#include "string2.h"
15
16/**
17 * cu_find_realpath - Find the realpath of the target file
18 * @cu_die: A DIE(dwarf information entry) of CU(compilation Unit)
19 * @fname: The tail filename of the target file
20 *
21 * Find the real(long) path of @fname in @cu_die.
22 */
23const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
24{
25 Dwarf_Files *files;
26 size_t nfiles, i;
27 const char *src = NULL;
28 int ret;
29
30 if (!fname)
31 return NULL;
32
33 ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
34 if (ret != 0)
35 return NULL;
36
37 for (i = 0; i < nfiles; i++) {
38 src = dwarf_filesrc(files, i, NULL, NULL);
39 if (strtailcmp(src, fname) == 0)
40 break;
41 }
42 if (i == nfiles)
43 return NULL;
44 return src;
45}
46
47/**
48 * cu_get_comp_dir - Get the path of compilation directory
49 * @cu_die: a CU DIE
50 *
51 * Get the path of compilation directory of given @cu_die.
52 * Since this depends on DW_AT_comp_dir, older gcc will not
53 * embedded it. In that case, this returns NULL.
54 */
55const char *cu_get_comp_dir(Dwarf_Die *cu_die)
56{
57 Dwarf_Attribute attr;
58 if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
59 return NULL;
60 return dwarf_formstring(&attr);
61}
62
63/* Unlike dwarf_getsrc_die(), cu_getsrc_die() only returns statement line */
64static Dwarf_Line *cu_getsrc_die(Dwarf_Die *cu_die, Dwarf_Addr addr)
65{
66 Dwarf_Addr laddr;
67 Dwarf_Lines *lines;
68 Dwarf_Line *line;
69 size_t nlines, l, u, n;
70 bool flag;
71
72 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0 ||
73 nlines == 0)
74 return NULL;
75
76 /* Lines are sorted by address, use binary search */
77 l = 0; u = nlines - 1;
78 while (l < u) {
79 n = u - (u - l) / 2;
80 line = dwarf_onesrcline(lines, n);
81 if (!line || dwarf_lineaddr(line, &laddr) != 0)
82 return NULL;
83 if (addr < laddr)
84 u = n - 1;
85 else
86 l = n;
87 }
88 /* Going backward to find the lowest line */
89 do {
90 line = dwarf_onesrcline(lines, --l);
91 if (!line || dwarf_lineaddr(line, &laddr) != 0)
92 return NULL;
93 } while (laddr == addr);
94 l++;
95 /* Going forward to find the statement line */
96 do {
97 line = dwarf_onesrcline(lines, l++);
98 if (!line || dwarf_lineaddr(line, &laddr) != 0 ||
99 dwarf_linebeginstatement(line, &flag) != 0)
100 return NULL;
101 if (laddr > addr)
102 return NULL;
103 } while (!flag);
104
105 return line;
106}
107
108/**
109 * cu_find_lineinfo - Get a line number and file name for given address
110 * @cu_die: a CU DIE
111 * @addr: An address
112 * @fname: a pointer which returns the file name string
113 * @lineno: a pointer which returns the line number
114 *
115 * Find a line number and file name for @addr in @cu_die.
116 */
117int cu_find_lineinfo(Dwarf_Die *cu_die, Dwarf_Addr addr,
118 const char **fname, int *lineno)
119{
120 Dwarf_Line *line;
121 Dwarf_Die die_mem;
122 Dwarf_Addr faddr;
123
124 if (die_find_realfunc(cu_die, addr, &die_mem)
125 && die_entrypc(&die_mem, &faddr) == 0 &&
126 faddr == addr) {
127 *fname = die_get_decl_file(&die_mem);
128 dwarf_decl_line(&die_mem, lineno);
129 goto out;
130 }
131
132 line = cu_getsrc_die(cu_die, addr);
133 if (line && dwarf_lineno(line, lineno) == 0) {
134 *fname = dwarf_linesrc(line, NULL, NULL);
135 if (!*fname)
136 /* line number is useless without filename */
137 *lineno = 0;
138 }
139
140out:
141 return (*lineno && *fname) ? *lineno : -ENOENT;
142}
143
144static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
145
146/**
147 * cu_walk_functions_at - Walk on function DIEs at given address
148 * @cu_die: A CU DIE
149 * @addr: An address
150 * @callback: A callback which called with found DIEs
151 * @data: A user data
152 *
153 * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
154 * should be subprogram or inlined-subroutines.
155 */
156int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
157 int (*callback)(Dwarf_Die *, void *), void *data)
158{
159 Dwarf_Die die_mem;
160 Dwarf_Die *sc_die;
161 int ret = -ENOENT;
162
163 /* Inlined function could be recursive. Trace it until fail */
164 for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
165 sc_die != NULL;
166 sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
167 &die_mem)) {
168 ret = callback(sc_die, data);
169 if (ret)
170 break;
171 }
172
173 return ret;
174
175}
176
177/**
178 * die_get_linkage_name - Get the linkage name of the object
179 * @dw_die: A DIE of the object
180 *
181 * Get the linkage name attribute of given @dw_die.
182 * For C++ binary, the linkage name will be the mangled symbol.
183 */
184const char *die_get_linkage_name(Dwarf_Die *dw_die)
185{
186 Dwarf_Attribute attr;
187
188 if (dwarf_attr_integrate(dw_die, DW_AT_linkage_name, &attr) == NULL)
189 return NULL;
190 return dwarf_formstring(&attr);
191}
192
193/**
194 * die_compare_name - Compare diename and tname
195 * @dw_die: a DIE
196 * @tname: a string of target name
197 *
198 * Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
199 */
200bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
201{
202 const char *name;
203
204 name = dwarf_diename(dw_die);
205 return name ? (strcmp(tname, name) == 0) : false;
206}
207
208/**
209 * die_match_name - Match diename/linkage name and glob
210 * @dw_die: a DIE
211 * @glob: a string of target glob pattern
212 *
213 * Glob matching the name of @dw_die and @glob. Return false if matching fail.
214 * This also match linkage name.
215 */
216bool die_match_name(Dwarf_Die *dw_die, const char *glob)
217{
218 const char *name;
219
220 name = dwarf_diename(dw_die);
221 if (name && strglobmatch(name, glob))
222 return true;
223 /* fall back to check linkage name */
224 name = die_get_linkage_name(dw_die);
225 if (name && strglobmatch(name, glob))
226 return true;
227
228 return false;
229}
230
231/**
232 * die_get_call_lineno - Get callsite line number of inline-function instance
233 * @in_die: a DIE of an inlined function instance
234 *
235 * Get call-site line number of @in_die. This means from where the inline
236 * function is called.
237 */
238int die_get_call_lineno(Dwarf_Die *in_die)
239{
240 Dwarf_Attribute attr;
241 Dwarf_Word ret;
242
243 if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
244 return -ENOENT;
245
246 dwarf_formudata(&attr, &ret);
247 return (int)ret;
248}
249
250/**
251 * die_get_type - Get type DIE
252 * @vr_die: a DIE of a variable
253 * @die_mem: where to store a type DIE
254 *
255 * Get a DIE of the type of given variable (@vr_die), and store
256 * it to die_mem. Return NULL if fails to get a type DIE.
257 */
258Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
259{
260 Dwarf_Attribute attr;
261
262 if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
263 dwarf_formref_die(&attr, die_mem))
264 return die_mem;
265 else
266 return NULL;
267}
268
269/* Get a type die, but skip qualifiers */
270Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
271{
272 int tag;
273
274 do {
275 vr_die = die_get_type(vr_die, die_mem);
276 if (!vr_die)
277 break;
278 tag = dwarf_tag(vr_die);
279 } while (tag == DW_TAG_const_type ||
280 tag == DW_TAG_restrict_type ||
281 tag == DW_TAG_volatile_type ||
282 tag == DW_TAG_shared_type);
283
284 return vr_die;
285}
286
287/**
288 * die_get_real_type - Get a type die, but skip qualifiers and typedef
289 * @vr_die: a DIE of a variable
290 * @die_mem: where to store a type DIE
291 *
292 * Get a DIE of the type of given variable (@vr_die), and store
293 * it to die_mem. Return NULL if fails to get a type DIE.
294 * If the type is qualifiers (e.g. const) or typedef, this skips it
295 * and tries to find real type (structure or basic types, e.g. int).
296 */
297Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
298{
299 do {
300 vr_die = __die_get_real_type(vr_die, die_mem);
301 } while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
302
303 return vr_die;
304}
305
306/* Get attribute and translate it as a udata */
307static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
308 Dwarf_Word *result)
309{
310 Dwarf_Attribute attr;
311
312 if (dwarf_attr_integrate(tp_die, attr_name, &attr) == NULL ||
313 dwarf_formudata(&attr, result) != 0)
314 return -ENOENT;
315
316 return 0;
317}
318
319/**
320 * die_is_signed_type - Check whether a type DIE is signed or not
321 * @tp_die: a DIE of a type
322 *
323 * Get the encoding of @tp_die and return true if the encoding
324 * is signed.
325 */
326bool die_is_signed_type(Dwarf_Die *tp_die)
327{
328 Dwarf_Word ret;
329
330 if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
331 return false;
332
333 return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
334 ret == DW_ATE_signed_fixed);
335}
336
337/**
338 * die_is_func_def - Ensure that this DIE is a subprogram and definition
339 * @dw_die: a DIE
340 *
341 * Ensure that this DIE is a subprogram and NOT a declaration. This
342 * returns true if @dw_die is a function definition.
343 **/
344bool die_is_func_def(Dwarf_Die *dw_die)
345{
346 Dwarf_Attribute attr;
347 Dwarf_Addr addr = 0;
348
349 if (dwarf_tag(dw_die) != DW_TAG_subprogram)
350 return false;
351
352 if (dwarf_attr(dw_die, DW_AT_declaration, &attr))
353 return false;
354
355 /*
356 * DW_AT_declaration can be lost from function declaration
357 * by gcc's bug #97060.
358 * So we need to check this subprogram DIE has DW_AT_inline
359 * or an entry address.
360 */
361 if (!dwarf_attr(dw_die, DW_AT_inline, &attr) &&
362 die_entrypc(dw_die, &addr) < 0)
363 return false;
364
365 return true;
366}
367
368/**
369 * die_entrypc - Returns entry PC (the lowest address) of a DIE
370 * @dw_die: a DIE
371 * @addr: where to store entry PC
372 *
373 * Since dwarf_entrypc() does not return entry PC if the DIE has only address
374 * range, we have to use this to retrieve the lowest address from the address
375 * range attribute.
376 */
377int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)
378{
379 Dwarf_Addr base, end;
380 Dwarf_Attribute attr;
381
382 if (!addr)
383 return -EINVAL;
384
385 if (dwarf_entrypc(dw_die, addr) == 0)
386 return 0;
387
388 /*
389 * Since the dwarf_ranges() will return 0 if there is no
390 * DW_AT_ranges attribute, we should check it first.
391 */
392 if (!dwarf_attr(dw_die, DW_AT_ranges, &attr))
393 return -ENOENT;
394
395 return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;
396}
397
398/**
399 * die_is_func_instance - Ensure that this DIE is an instance of a subprogram
400 * @dw_die: a DIE
401 *
402 * Ensure that this DIE is an instance (which has an entry address).
403 * This returns true if @dw_die is a function instance. If not, the @dw_die
404 * must be a prototype. You can use die_walk_instances() to find actual
405 * instances.
406 **/
407bool die_is_func_instance(Dwarf_Die *dw_die)
408{
409 Dwarf_Addr tmp;
410 Dwarf_Attribute attr_mem;
411 int tag = dwarf_tag(dw_die);
412
413 if (tag != DW_TAG_subprogram &&
414 tag != DW_TAG_inlined_subroutine)
415 return false;
416
417 return dwarf_entrypc(dw_die, &tmp) == 0 ||
418 dwarf_attr(dw_die, DW_AT_ranges, &attr_mem) != NULL;
419}
420
421/**
422 * die_get_data_member_location - Get the data-member offset
423 * @mb_die: a DIE of a member of a data structure
424 * @offs: The offset of the member in the data structure
425 *
426 * Get the offset of @mb_die in the data structure including @mb_die, and
427 * stores result offset to @offs. If any error occurs this returns errno.
428 */
429int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
430{
431 Dwarf_Attribute attr;
432 Dwarf_Op *expr;
433 size_t nexpr;
434 int ret;
435
436 if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
437 return -ENOENT;
438
439 if (dwarf_formudata(&attr, offs) != 0) {
440 /* DW_AT_data_member_location should be DW_OP_plus_uconst */
441 ret = dwarf_getlocation(&attr, &expr, &nexpr);
442 if (ret < 0 || nexpr == 0)
443 return -ENOENT;
444
445 if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
446 pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
447 expr[0].atom, nexpr);
448 return -ENOTSUP;
449 }
450 *offs = (Dwarf_Word)expr[0].number;
451 }
452 return 0;
453}
454
455/* Get the call file index number in CU DIE */
456static int die_get_call_fileno(Dwarf_Die *in_die)
457{
458 Dwarf_Word idx;
459
460 if (die_get_attr_udata(in_die, DW_AT_call_file, &idx) == 0)
461 return (int)idx;
462 else
463 return -ENOENT;
464}
465
466/* Get the declared file index number in CU DIE */
467static int die_get_decl_fileno(Dwarf_Die *pdie)
468{
469 Dwarf_Word idx;
470
471 if (die_get_attr_udata(pdie, DW_AT_decl_file, &idx) == 0)
472 return (int)idx;
473 else
474 return -ENOENT;
475}
476
477/* Return the file name by index */
478static const char *die_get_file_name(Dwarf_Die *dw_die, int idx)
479{
480 Dwarf_Die cu_die;
481 Dwarf_Files *files;
482 Dwarf_Attribute attr_mem;
483
484 if (idx < 0 || !dwarf_attr_integrate(dw_die, DW_AT_decl_file, &attr_mem) ||
485 !dwarf_cu_die(attr_mem.cu, &cu_die, NULL, NULL, NULL, NULL, NULL, NULL) ||
486 dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
487 return NULL;
488
489 return dwarf_filesrc(files, idx, NULL, NULL);
490}
491
492/**
493 * die_get_call_file - Get callsite file name of inlined function instance
494 * @in_die: a DIE of an inlined function instance
495 *
496 * Get call-site file name of @in_die. This means from which file the inline
497 * function is called.
498 */
499const char *die_get_call_file(Dwarf_Die *in_die)
500{
501 return die_get_file_name(in_die, die_get_call_fileno(in_die));
502}
503
504/**
505 * die_get_decl_file - Find the declared file name of this DIE
506 * @dw_die: a DIE for something declared.
507 *
508 * Get declared file name of @dw_die.
509 * NOTE: Since some version of clang DWARF5 implementation incorrectly uses
510 * file index 0 for DW_AT_decl_file, die_get_decl_file() will return NULL for
511 * such cases. Use this function instead.
512 */
513const char *die_get_decl_file(Dwarf_Die *dw_die)
514{
515 return die_get_file_name(dw_die, die_get_decl_fileno(dw_die));
516}
517
518/**
519 * die_find_child - Generic DIE search function in DIE tree
520 * @rt_die: a root DIE
521 * @callback: a callback function
522 * @data: a user data passed to the callback function
523 * @die_mem: a buffer for result DIE
524 *
525 * Trace DIE tree from @rt_die and call @callback for each child DIE.
526 * If @callback returns DIE_FIND_CB_END, this stores the DIE into
527 * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
528 * this continues to trace the tree. Optionally, @callback can return
529 * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
530 * the children and trace only the siblings respectively.
531 * Returns NULL if @callback can't find any appropriate DIE.
532 */
533Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
534 int (*callback)(Dwarf_Die *, void *),
535 void *data, Dwarf_Die *die_mem)
536{
537 Dwarf_Die child_die;
538 int ret;
539
540 ret = dwarf_child(rt_die, die_mem);
541 if (ret != 0)
542 return NULL;
543
544 do {
545 ret = callback(die_mem, data);
546 if (ret == DIE_FIND_CB_END)
547 return die_mem;
548
549 if ((ret & DIE_FIND_CB_CHILD) &&
550 die_find_child(die_mem, callback, data, &child_die)) {
551 memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
552 return die_mem;
553 }
554 } while ((ret & DIE_FIND_CB_SIBLING) &&
555 dwarf_siblingof(die_mem, die_mem) == 0);
556
557 return NULL;
558}
559
560struct __addr_die_search_param {
561 Dwarf_Addr addr;
562 Dwarf_Die *die_mem;
563};
564
565static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
566{
567 struct __addr_die_search_param *ad = data;
568 Dwarf_Addr addr = 0;
569
570 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
571 !dwarf_highpc(fn_die, &addr) &&
572 addr == ad->addr) {
573 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
574 return DWARF_CB_ABORT;
575 }
576 return DWARF_CB_OK;
577}
578
579/**
580 * die_find_tailfunc - Search for a non-inlined function with tail call at
581 * given address
582 * @cu_die: a CU DIE which including @addr
583 * @addr: target address
584 * @die_mem: a buffer for result DIE
585 *
586 * Search for a non-inlined function DIE with tail call at @addr. Stores the
587 * DIE to @die_mem and returns it if found. Returns NULL if failed.
588 */
589Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
590 Dwarf_Die *die_mem)
591{
592 struct __addr_die_search_param ad;
593 ad.addr = addr;
594 ad.die_mem = die_mem;
595 /* dwarf_getscopes can't find subprogram. */
596 if (!dwarf_getfuncs(cu_die, __die_search_func_tail_cb, &ad, 0))
597 return NULL;
598 else
599 return die_mem;
600}
601
602/* die_find callback for non-inlined function search */
603static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
604{
605 struct __addr_die_search_param *ad = data;
606
607 /*
608 * Since a declaration entry doesn't has given pc, this always returns
609 * function definition entry.
610 */
611 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
612 dwarf_haspc(fn_die, ad->addr)) {
613 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
614 return DWARF_CB_ABORT;
615 }
616 return DWARF_CB_OK;
617}
618
619/**
620 * die_find_realfunc - Search a non-inlined function at given address
621 * @cu_die: a CU DIE which including @addr
622 * @addr: target address
623 * @die_mem: a buffer for result DIE
624 *
625 * Search a non-inlined function DIE which includes @addr. Stores the
626 * DIE to @die_mem and returns it if found. Returns NULL if failed.
627 */
628Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
629 Dwarf_Die *die_mem)
630{
631 struct __addr_die_search_param ad;
632 ad.addr = addr;
633 ad.die_mem = die_mem;
634 /* dwarf_getscopes can't find subprogram. */
635 if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
636 return NULL;
637 else
638 return die_mem;
639}
640
641/* die_find callback for inline function search */
642static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
643{
644 Dwarf_Addr *addr = data;
645
646 if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
647 dwarf_haspc(die_mem, *addr))
648 return DIE_FIND_CB_END;
649
650 return DIE_FIND_CB_CONTINUE;
651}
652
653/**
654 * die_find_top_inlinefunc - Search the top inlined function at given address
655 * @sp_die: a subprogram DIE which including @addr
656 * @addr: target address
657 * @die_mem: a buffer for result DIE
658 *
659 * Search an inlined function DIE which includes @addr. Stores the
660 * DIE to @die_mem and returns it if found. Returns NULL if failed.
661 * Even if several inlined functions are expanded recursively, this
662 * doesn't trace it down, and returns the topmost one.
663 */
664Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
665 Dwarf_Die *die_mem)
666{
667 return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
668}
669
670/**
671 * die_find_inlinefunc - Search an inlined function at given address
672 * @sp_die: a subprogram DIE which including @addr
673 * @addr: target address
674 * @die_mem: a buffer for result DIE
675 *
676 * Search an inlined function DIE which includes @addr. Stores the
677 * DIE to @die_mem and returns it if found. Returns NULL if failed.
678 * If several inlined functions are expanded recursively, this trace
679 * it down and returns deepest one.
680 */
681Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
682 Dwarf_Die *die_mem)
683{
684 Dwarf_Die tmp_die;
685
686 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
687 if (!sp_die)
688 return NULL;
689
690 /* Inlined function could be recursive. Trace it until fail */
691 while (sp_die) {
692 memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
693 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
694 &tmp_die);
695 }
696
697 return die_mem;
698}
699
700static int __die_find_func_rettype_cb(Dwarf_Die *die_mem, void *data)
701{
702 const char *func_name;
703
704 if (dwarf_tag(die_mem) != DW_TAG_subprogram)
705 return DIE_FIND_CB_SIBLING;
706
707 func_name = dwarf_diename(die_mem);
708 if (func_name && !strcmp(func_name, data))
709 return DIE_FIND_CB_END;
710
711 return DIE_FIND_CB_SIBLING;
712}
713
714/**
715 * die_find_func_rettype - Search a return type of function
716 * @cu_die: a CU DIE
717 * @name: target function name
718 * @die_mem: a buffer for result DIE
719 *
720 * Search a non-inlined function which matches to @name and stores the
721 * return type of the function to @die_mem and returns it if found.
722 * Returns NULL if failed. Note that it doesn't needs to find a
723 * definition of the function, so it doesn't match with address.
724 * Most likely, it can find a declaration at the top level. Thus the
725 * callback function continues to sibling entries only.
726 */
727Dwarf_Die *die_find_func_rettype(Dwarf_Die *cu_die, const char *name,
728 Dwarf_Die *die_mem)
729{
730 Dwarf_Die tmp_die;
731
732 cu_die = die_find_child(cu_die, __die_find_func_rettype_cb,
733 (void *)name, &tmp_die);
734 if (!cu_die)
735 return NULL;
736
737 if (die_get_real_type(&tmp_die, die_mem) == NULL)
738 return NULL;
739
740 return die_mem;
741}
742
743struct __instance_walk_param {
744 void *addr;
745 int (*callback)(Dwarf_Die *, void *);
746 void *data;
747 int retval;
748};
749
750static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
751{
752 struct __instance_walk_param *iwp = data;
753 Dwarf_Attribute attr_mem;
754 Dwarf_Die origin_mem;
755 Dwarf_Attribute *attr;
756 Dwarf_Die *origin;
757 int tmp;
758
759 if (!die_is_func_instance(inst))
760 return DIE_FIND_CB_CONTINUE;
761
762 attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
763 if (attr == NULL)
764 return DIE_FIND_CB_CONTINUE;
765
766 origin = dwarf_formref_die(attr, &origin_mem);
767 if (origin == NULL || origin->addr != iwp->addr)
768 return DIE_FIND_CB_CONTINUE;
769
770 /* Ignore redundant instances */
771 if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
772 dwarf_decl_line(origin, &tmp);
773 if (die_get_call_lineno(inst) == tmp) {
774 tmp = die_get_decl_fileno(origin);
775 if (die_get_call_fileno(inst) == tmp)
776 return DIE_FIND_CB_CONTINUE;
777 }
778 }
779
780 iwp->retval = iwp->callback(inst, iwp->data);
781
782 return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
783}
784
785/**
786 * die_walk_instances - Walk on instances of given DIE
787 * @or_die: an abstract original DIE
788 * @callback: a callback function which is called with instance DIE
789 * @data: user data
790 *
791 * Walk on the instances of give @in_die. @in_die must be an inlined function
792 * declaration. This returns the return value of @callback if it returns
793 * non-zero value, or -ENOENT if there is no instance.
794 */
795int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
796 void *data)
797{
798 Dwarf_Die cu_die;
799 Dwarf_Die die_mem;
800 struct __instance_walk_param iwp = {
801 .addr = or_die->addr,
802 .callback = callback,
803 .data = data,
804 .retval = -ENOENT,
805 };
806
807 if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
808 return -ENOENT;
809
810 die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
811
812 return iwp.retval;
813}
814
815/* Line walker internal parameters */
816struct __line_walk_param {
817 bool recursive;
818 line_walk_callback_t callback;
819 void *data;
820 int retval;
821};
822
823static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
824{
825 struct __line_walk_param *lw = data;
826 Dwarf_Addr addr = 0;
827 const char *fname;
828 int lineno;
829
830 if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
831 fname = die_get_call_file(in_die);
832 lineno = die_get_call_lineno(in_die);
833 if (fname && lineno > 0 && die_entrypc(in_die, &addr) == 0) {
834 lw->retval = lw->callback(fname, lineno, addr, lw->data);
835 if (lw->retval != 0)
836 return DIE_FIND_CB_END;
837 }
838 if (!lw->recursive)
839 return DIE_FIND_CB_SIBLING;
840 }
841
842 if (addr) {
843 fname = die_get_decl_file(in_die);
844 if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
845 lw->retval = lw->callback(fname, lineno, addr, lw->data);
846 if (lw->retval != 0)
847 return DIE_FIND_CB_END;
848 }
849 }
850
851 /* Continue to search nested inlined function call-sites */
852 return DIE_FIND_CB_CONTINUE;
853}
854
855/* Walk on lines of blocks included in given DIE */
856static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
857 line_walk_callback_t callback, void *data)
858{
859 struct __line_walk_param lw = {
860 .recursive = recursive,
861 .callback = callback,
862 .data = data,
863 .retval = 0,
864 };
865 Dwarf_Die die_mem;
866 Dwarf_Addr addr;
867 const char *fname;
868 int lineno;
869
870 /* Handle function declaration line */
871 fname = die_get_decl_file(sp_die);
872 if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
873 die_entrypc(sp_die, &addr) == 0) {
874 lw.retval = callback(fname, lineno, addr, data);
875 if (lw.retval != 0)
876 goto done;
877 }
878 die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
879done:
880 return lw.retval;
881}
882
883static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
884{
885 struct __line_walk_param *lw = data;
886
887 /*
888 * Since inlined function can include another inlined function in
889 * the same file, we need to walk in it recursively.
890 */
891 lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
892 if (lw->retval != 0)
893 return DWARF_CB_ABORT;
894
895 return DWARF_CB_OK;
896}
897
898/**
899 * die_walk_lines - Walk on lines inside given DIE
900 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
901 * @callback: callback routine
902 * @data: user data
903 *
904 * Walk on all lines inside given @rt_die and call @callback on each line.
905 * If the @rt_die is a function, walk only on the lines inside the function,
906 * otherwise @rt_die must be a CU DIE.
907 * Note that this walks not only dwarf line list, but also function entries
908 * and inline call-site.
909 */
910int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
911{
912 Dwarf_Lines *lines;
913 Dwarf_Line *line;
914 Dwarf_Addr addr;
915 const char *fname, *decf = NULL, *inf = NULL;
916 int lineno, ret = 0;
917 int decl = 0, inl;
918 Dwarf_Die die_mem, *cu_die;
919 size_t nlines, i;
920 bool flag;
921
922 /* Get the CU die */
923 if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
924 cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
925 dwarf_decl_line(rt_die, &decl);
926 decf = die_get_decl_file(rt_die);
927 if (!decf) {
928 pr_debug2("Failed to get the declared file name of %s\n",
929 dwarf_diename(rt_die));
930 return -EINVAL;
931 }
932 } else
933 cu_die = rt_die;
934 if (!cu_die) {
935 pr_debug2("Failed to get CU from given DIE.\n");
936 return -EINVAL;
937 }
938
939 /* Get lines list in the CU */
940 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
941 pr_debug2("Failed to get source lines on this CU.\n");
942 return -ENOENT;
943 }
944 pr_debug2("Get %zd lines from this CU\n", nlines);
945
946 /* Walk on the lines on lines list */
947 for (i = 0; i < nlines; i++) {
948 line = dwarf_onesrcline(lines, i);
949 if (line == NULL ||
950 dwarf_lineno(line, &lineno) != 0 ||
951 dwarf_lineaddr(line, &addr) != 0) {
952 pr_debug2("Failed to get line info. "
953 "Possible error in debuginfo.\n");
954 continue;
955 }
956 /* Skip end-of-sequence */
957 if (dwarf_lineendsequence(line, &flag) != 0 || flag)
958 continue;
959 /* Skip Non statement line-info */
960 if (dwarf_linebeginstatement(line, &flag) != 0 || !flag)
961 continue;
962 /* Filter lines based on address */
963 if (rt_die != cu_die) {
964 /*
965 * Address filtering
966 * The line is included in given function, and
967 * no inline block includes it.
968 */
969 if (!dwarf_haspc(rt_die, addr))
970 continue;
971
972 if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
973 /* Call-site check */
974 inf = die_get_call_file(&die_mem);
975 if ((inf && !strcmp(inf, decf)) &&
976 die_get_call_lineno(&die_mem) == lineno)
977 goto found;
978
979 dwarf_decl_line(&die_mem, &inl);
980 if (inl != decl ||
981 decf != die_get_decl_file(&die_mem))
982 continue;
983 }
984 }
985found:
986 /* Get source line */
987 fname = dwarf_linesrc(line, NULL, NULL);
988
989 ret = callback(fname, lineno, addr, data);
990 if (ret != 0)
991 return ret;
992 }
993
994 /*
995 * Dwarf lines doesn't include function declarations and inlined
996 * subroutines. We have to check functions list or given function.
997 */
998 if (rt_die != cu_die)
999 /*
1000 * Don't need walk inlined functions recursively, because
1001 * inner inlined functions don't have the lines of the
1002 * specified function.
1003 */
1004 ret = __die_walk_funclines(rt_die, false, callback, data);
1005 else {
1006 struct __line_walk_param param = {
1007 .callback = callback,
1008 .data = data,
1009 .retval = 0,
1010 };
1011 dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
1012 ret = param.retval;
1013 }
1014
1015 return ret;
1016}
1017
1018struct __find_variable_param {
1019 const char *name;
1020 Dwarf_Addr addr;
1021};
1022
1023static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
1024{
1025 struct __find_variable_param *fvp = data;
1026 Dwarf_Attribute attr;
1027 int tag;
1028
1029 tag = dwarf_tag(die_mem);
1030 if ((tag == DW_TAG_formal_parameter ||
1031 tag == DW_TAG_variable) &&
1032 die_compare_name(die_mem, fvp->name) &&
1033 /*
1034 * Does the DIE have location information or const value
1035 * or external instance?
1036 */
1037 (dwarf_attr(die_mem, DW_AT_external, &attr) ||
1038 dwarf_attr(die_mem, DW_AT_location, &attr) ||
1039 dwarf_attr(die_mem, DW_AT_const_value, &attr)))
1040 return DIE_FIND_CB_END;
1041 if (dwarf_haspc(die_mem, fvp->addr))
1042 return DIE_FIND_CB_CONTINUE;
1043 else
1044 return DIE_FIND_CB_SIBLING;
1045}
1046
1047/**
1048 * die_find_variable_at - Find a given name variable at given address
1049 * @sp_die: a function DIE
1050 * @name: variable name
1051 * @addr: address
1052 * @die_mem: a buffer for result DIE
1053 *
1054 * Find a variable DIE called @name at @addr in @sp_die.
1055 */
1056Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
1057 Dwarf_Addr addr, Dwarf_Die *die_mem)
1058{
1059 struct __find_variable_param fvp = { .name = name, .addr = addr};
1060
1061 return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
1062 die_mem);
1063}
1064
1065static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
1066{
1067 const char *name = data;
1068
1069 if (dwarf_tag(die_mem) == DW_TAG_member) {
1070 if (die_compare_name(die_mem, name))
1071 return DIE_FIND_CB_END;
1072 else if (!dwarf_diename(die_mem)) { /* Unnamed structure */
1073 Dwarf_Die type_die, tmp_die;
1074 if (die_get_type(die_mem, &type_die) &&
1075 die_find_member(&type_die, name, &tmp_die))
1076 return DIE_FIND_CB_END;
1077 }
1078 }
1079 return DIE_FIND_CB_SIBLING;
1080}
1081
1082/**
1083 * die_find_member - Find a given name member in a data structure
1084 * @st_die: a data structure type DIE
1085 * @name: member name
1086 * @die_mem: a buffer for result DIE
1087 *
1088 * Find a member DIE called @name in @st_die.
1089 */
1090Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
1091 Dwarf_Die *die_mem)
1092{
1093 return die_find_child(st_die, __die_find_member_cb, (void *)name,
1094 die_mem);
1095}
1096
1097/**
1098 * die_get_typename_from_type - Get the name of given type DIE
1099 * @type_die: a type DIE
1100 * @buf: a strbuf for result type name
1101 *
1102 * Get the name of @type_die and stores it to @buf. Return 0 if succeeded.
1103 * and Return -ENOENT if failed to find type name.
1104 * Note that the result will stores typedef name if possible, and stores
1105 * "*(function_type)" if the type is a function pointer.
1106 */
1107int die_get_typename_from_type(Dwarf_Die *type_die, struct strbuf *buf)
1108{
1109 int tag, ret;
1110 const char *tmp = "";
1111
1112 tag = dwarf_tag(type_die);
1113 if (tag == DW_TAG_pointer_type)
1114 tmp = "*";
1115 else if (tag == DW_TAG_array_type)
1116 tmp = "[]";
1117 else if (tag == DW_TAG_subroutine_type) {
1118 /* Function pointer */
1119 return strbuf_add(buf, "(function_type)", 15);
1120 } else {
1121 const char *name = dwarf_diename(type_die);
1122
1123 if (tag == DW_TAG_union_type)
1124 tmp = "union ";
1125 else if (tag == DW_TAG_structure_type)
1126 tmp = "struct ";
1127 else if (tag == DW_TAG_enumeration_type)
1128 tmp = "enum ";
1129 else if (name == NULL)
1130 return -ENOENT;
1131 /* Write a base name */
1132 return strbuf_addf(buf, "%s%s", tmp, name ?: "");
1133 }
1134 ret = die_get_typename(type_die, buf);
1135 if (ret < 0) {
1136 /* void pointer has no type attribute */
1137 if (tag == DW_TAG_pointer_type && ret == -ENOENT)
1138 return strbuf_addf(buf, "void*");
1139
1140 return ret;
1141 }
1142 return strbuf_addstr(buf, tmp);
1143}
1144
1145/**
1146 * die_get_typename - Get the name of given variable DIE
1147 * @vr_die: a variable DIE
1148 * @buf: a strbuf for result type name
1149 *
1150 * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
1151 * and Return -ENOENT if failed to find type name.
1152 * Note that the result will stores typedef name if possible, and stores
1153 * "*(function_type)" if the type is a function pointer.
1154 */
1155int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
1156{
1157 Dwarf_Die type;
1158
1159 if (__die_get_real_type(vr_die, &type) == NULL)
1160 return -ENOENT;
1161
1162 return die_get_typename_from_type(&type, buf);
1163}
1164
1165/**
1166 * die_get_varname - Get the name and type of given variable DIE
1167 * @vr_die: a variable DIE
1168 * @buf: a strbuf for type and variable name
1169 *
1170 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
1171 */
1172int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
1173{
1174 int ret;
1175
1176 ret = die_get_typename(vr_die, buf);
1177 if (ret < 0) {
1178 pr_debug("Failed to get type, make it unknown.\n");
1179 ret = strbuf_add(buf, "(unknown_type)", 14);
1180 }
1181
1182 return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
1183}
1184
1185static int reg_from_dwarf_op(Dwarf_Op *op)
1186{
1187 switch (op->atom) {
1188 case DW_OP_reg0 ... DW_OP_reg31:
1189 return op->atom - DW_OP_reg0;
1190 case DW_OP_breg0 ... DW_OP_breg31:
1191 return op->atom - DW_OP_breg0;
1192 case DW_OP_regx:
1193 case DW_OP_bregx:
1194 return op->number;
1195 case DW_OP_fbreg:
1196 return DWARF_REG_FB;
1197 default:
1198 break;
1199 }
1200 return -1;
1201}
1202
1203static int offset_from_dwarf_op(Dwarf_Op *op)
1204{
1205 switch (op->atom) {
1206 case DW_OP_reg0 ... DW_OP_reg31:
1207 case DW_OP_regx:
1208 return 0;
1209 case DW_OP_breg0 ... DW_OP_breg31:
1210 case DW_OP_fbreg:
1211 return op->number;
1212 case DW_OP_bregx:
1213 return op->number2;
1214 default:
1215 break;
1216 }
1217 return -1;
1218}
1219
1220static bool check_allowed_ops(Dwarf_Op *ops, size_t nops)
1221{
1222 /* The first op is checked separately */
1223 ops++;
1224 nops--;
1225
1226 /*
1227 * It needs to make sure if the location expression matches to the given
1228 * register and offset exactly. Thus it rejects any complex expressions
1229 * and only allows a few of selected operators that doesn't change the
1230 * location.
1231 */
1232 while (nops) {
1233 switch (ops->atom) {
1234 case DW_OP_stack_value:
1235 case DW_OP_deref_size:
1236 case DW_OP_deref:
1237 case DW_OP_piece:
1238 break;
1239 default:
1240 return false;
1241 }
1242 ops++;
1243 nops--;
1244 }
1245 return true;
1246}
1247
1248/**
1249 * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
1250 * @sp_die: a subprogram DIE
1251 * @vr_die: a variable DIE
1252 * @buf: a strbuf for variable byte offset range
1253 *
1254 * Get the innermost scope range of @vr_die and stores it in @buf as
1255 * "@<function_name+[NN-NN,NN-NN]>".
1256 */
1257static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
1258 struct strbuf *buf)
1259{
1260 Dwarf_Die *scopes;
1261 int count;
1262 size_t offset = 0;
1263 Dwarf_Addr base;
1264 Dwarf_Addr start, end;
1265 Dwarf_Addr entry;
1266 int ret;
1267 bool first = true;
1268 const char *name;
1269
1270 ret = die_entrypc(sp_die, &entry);
1271 if (ret)
1272 return ret;
1273
1274 name = dwarf_diename(sp_die);
1275 if (!name)
1276 return -ENOENT;
1277
1278 count = dwarf_getscopes_die(vr_die, &scopes);
1279
1280 /* (*SCOPES)[1] is the DIE for the scope containing that scope */
1281 if (count <= 1) {
1282 ret = -EINVAL;
1283 goto out;
1284 }
1285
1286 while ((offset = dwarf_ranges(&scopes[1], offset, &base,
1287 &start, &end)) > 0) {
1288 start -= entry;
1289 end -= entry;
1290
1291 if (first) {
1292 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1293 name, start, end);
1294 first = false;
1295 } else {
1296 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1297 start, end);
1298 }
1299 if (ret < 0)
1300 goto out;
1301 }
1302
1303 if (!first)
1304 ret = strbuf_add(buf, "]>", 2);
1305
1306out:
1307 free(scopes);
1308 return ret;
1309}
1310
1311/**
1312 * die_get_var_range - Get byte offset range of given variable DIE
1313 * @sp_die: a subprogram DIE
1314 * @vr_die: a variable DIE
1315 * @buf: a strbuf for type and variable name and byte offset range
1316 *
1317 * Get the byte offset range of @vr_die and stores it in @buf as
1318 * "@<function_name+[NN-NN,NN-NN]>".
1319 */
1320int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
1321{
1322 int ret = 0;
1323 Dwarf_Addr base;
1324 Dwarf_Addr start, end;
1325 Dwarf_Addr entry;
1326 Dwarf_Op *op;
1327 size_t nops;
1328 size_t offset = 0;
1329 Dwarf_Attribute attr;
1330 bool first = true;
1331 const char *name;
1332
1333 ret = die_entrypc(sp_die, &entry);
1334 if (ret)
1335 return ret;
1336
1337 name = dwarf_diename(sp_die);
1338 if (!name)
1339 return -ENOENT;
1340
1341 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
1342 return -EINVAL;
1343
1344 while ((offset = dwarf_getlocations(&attr, offset, &base,
1345 &start, &end, &op, &nops)) > 0) {
1346 if (start == 0) {
1347 /* Single Location Descriptions */
1348 ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
1349 goto out;
1350 }
1351
1352 /* Location Lists */
1353 start -= entry;
1354 end -= entry;
1355 if (first) {
1356 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1357 name, start, end);
1358 first = false;
1359 } else {
1360 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1361 start, end);
1362 }
1363 if (ret < 0)
1364 goto out;
1365 }
1366
1367 if (!first)
1368 ret = strbuf_add(buf, "]>", 2);
1369out:
1370 return ret;
1371}
1372
1373/* Interval parameters for __die_find_var_reg_cb() */
1374struct find_var_data {
1375 /* Target instruction address */
1376 Dwarf_Addr pc;
1377 /* Target memory address (for global data) */
1378 Dwarf_Addr addr;
1379 /* Target register */
1380 unsigned reg;
1381 /* Access offset, set for global data */
1382 int offset;
1383 /* True if the current register is the frame base */
1384 bool is_fbreg;
1385};
1386
1387/* Max number of registers DW_OP_regN supports */
1388#define DWARF_OP_DIRECT_REGS 32
1389
1390static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data,
1391 u64 addr_offset, u64 addr_type, bool is_pointer)
1392{
1393 Dwarf_Die type_die;
1394 Dwarf_Word size;
1395
1396 if (addr_offset == addr_type) {
1397 /* Update offset relative to the start of the variable */
1398 data->offset = 0;
1399 return true;
1400 }
1401
1402 if (addr_offset < addr_type)
1403 return false;
1404
1405 if (die_get_real_type(die_mem, &type_die) == NULL)
1406 return false;
1407
1408 if (is_pointer && dwarf_tag(&type_die) == DW_TAG_pointer_type) {
1409 /* Get the target type of the pointer */
1410 if (die_get_real_type(&type_die, &type_die) == NULL)
1411 return false;
1412 }
1413
1414 if (dwarf_aggregate_size(&type_die, &size) < 0)
1415 return false;
1416
1417 if (addr_offset >= addr_type + size)
1418 return false;
1419
1420 /* Update offset relative to the start of the variable */
1421 data->offset = addr_offset - addr_type;
1422 return true;
1423}
1424
1425/* Only checks direct child DIEs in the given scope. */
1426static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg)
1427{
1428 struct find_var_data *data = arg;
1429 int tag = dwarf_tag(die_mem);
1430 ptrdiff_t off = 0;
1431 Dwarf_Attribute attr;
1432 Dwarf_Addr base, start, end;
1433 Dwarf_Op *ops;
1434 size_t nops;
1435
1436 if (tag != DW_TAG_variable && tag != DW_TAG_formal_parameter)
1437 return DIE_FIND_CB_SIBLING;
1438
1439 if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL)
1440 return DIE_FIND_CB_SIBLING;
1441
1442 while ((off = dwarf_getlocations(&attr, off, &base, &start, &end, &ops, &nops)) > 0) {
1443 /* Assuming the location list is sorted by address */
1444 if (end <= data->pc)
1445 continue;
1446 if (start > data->pc)
1447 break;
1448
1449 /* Local variables accessed using frame base register */
1450 if (data->is_fbreg && ops->atom == DW_OP_fbreg &&
1451 check_allowed_ops(ops, nops) &&
1452 match_var_offset(die_mem, data, data->offset, ops->number,
1453 /*is_pointer=*/false))
1454 return DIE_FIND_CB_END;
1455
1456 /* Only match with a simple case */
1457 if (data->reg < DWARF_OP_DIRECT_REGS) {
1458 /* pointer variables saved in a register 0 to 31 */
1459 if (ops->atom == (DW_OP_reg0 + data->reg) &&
1460 check_allowed_ops(ops, nops) &&
1461 match_var_offset(die_mem, data, data->offset, 0,
1462 /*is_pointer=*/true))
1463 return DIE_FIND_CB_END;
1464
1465 /* Local variables accessed by a register + offset */
1466 if (ops->atom == (DW_OP_breg0 + data->reg) &&
1467 check_allowed_ops(ops, nops) &&
1468 match_var_offset(die_mem, data, data->offset, ops->number,
1469 /*is_pointer=*/false))
1470 return DIE_FIND_CB_END;
1471 } else {
1472 /* pointer variables saved in a register 32 or above */
1473 if (ops->atom == DW_OP_regx && ops->number == data->reg &&
1474 check_allowed_ops(ops, nops) &&
1475 match_var_offset(die_mem, data, data->offset, 0,
1476 /*is_pointer=*/true))
1477 return DIE_FIND_CB_END;
1478
1479 /* Local variables accessed by a register + offset */
1480 if (ops->atom == DW_OP_bregx && data->reg == ops->number &&
1481 check_allowed_ops(ops, nops) &&
1482 match_var_offset(die_mem, data, data->offset, ops->number2,
1483 /*is_poitner=*/false))
1484 return DIE_FIND_CB_END;
1485 }
1486 }
1487 return DIE_FIND_CB_SIBLING;
1488}
1489
1490/**
1491 * die_find_variable_by_reg - Find a variable saved in a register
1492 * @sc_die: a scope DIE
1493 * @pc: the program address to find
1494 * @reg: the register number to find
1495 * @poffset: pointer to offset, will be updated for fbreg case
1496 * @is_fbreg: boolean value if the current register is the frame base
1497 * @die_mem: a buffer to save the resulting DIE
1498 *
1499 * Find the variable DIE accessed by the given register. It'll update the @offset
1500 * when the variable is in the stack.
1501 */
1502Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die, Dwarf_Addr pc, int reg,
1503 int *poffset, bool is_fbreg,
1504 Dwarf_Die *die_mem)
1505{
1506 struct find_var_data data = {
1507 .pc = pc,
1508 .reg = reg,
1509 .offset = *poffset,
1510 .is_fbreg = is_fbreg,
1511 };
1512 Dwarf_Die *result;
1513
1514 result = die_find_child(sc_die, __die_find_var_reg_cb, &data, die_mem);
1515 if (result)
1516 *poffset = data.offset;
1517 return result;
1518}
1519
1520/* Only checks direct child DIEs in the given scope */
1521static int __die_find_var_addr_cb(Dwarf_Die *die_mem, void *arg)
1522{
1523 struct find_var_data *data = arg;
1524 int tag = dwarf_tag(die_mem);
1525 ptrdiff_t off = 0;
1526 Dwarf_Attribute attr;
1527 Dwarf_Addr base, start, end;
1528 Dwarf_Op *ops;
1529 size_t nops;
1530
1531 if (tag != DW_TAG_variable)
1532 return DIE_FIND_CB_SIBLING;
1533
1534 if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL)
1535 return DIE_FIND_CB_SIBLING;
1536
1537 while ((off = dwarf_getlocations(&attr, off, &base, &start, &end, &ops, &nops)) > 0) {
1538 if (ops->atom != DW_OP_addr)
1539 continue;
1540
1541 if (check_allowed_ops(ops, nops) &&
1542 match_var_offset(die_mem, data, data->addr, ops->number,
1543 /*is_pointer=*/false))
1544 return DIE_FIND_CB_END;
1545 }
1546 return DIE_FIND_CB_SIBLING;
1547}
1548
1549/**
1550 * die_find_variable_by_addr - Find variable located at given address
1551 * @sc_die: a scope DIE
1552 * @addr: the data address to find
1553 * @die_mem: a buffer to save the resulting DIE
1554 * @offset: the offset in the resulting type
1555 *
1556 * Find the variable DIE located at the given address (in PC-relative mode).
1557 * This is usually for global variables.
1558 */
1559Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr addr,
1560 Dwarf_Die *die_mem, int *offset)
1561{
1562 struct find_var_data data = {
1563 .addr = addr,
1564 };
1565 Dwarf_Die *result;
1566
1567 result = die_find_child(sc_die, __die_find_var_addr_cb, &data, die_mem);
1568 if (result)
1569 *offset = data.offset;
1570 return result;
1571}
1572
1573static int __die_collect_vars_cb(Dwarf_Die *die_mem, void *arg)
1574{
1575 struct die_var_type **var_types = arg;
1576 Dwarf_Die type_die;
1577 int tag = dwarf_tag(die_mem);
1578 Dwarf_Attribute attr;
1579 Dwarf_Addr base, start, end;
1580 Dwarf_Op *ops;
1581 size_t nops;
1582 struct die_var_type *vt;
1583
1584 if (tag != DW_TAG_variable && tag != DW_TAG_formal_parameter)
1585 return DIE_FIND_CB_SIBLING;
1586
1587 if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL)
1588 return DIE_FIND_CB_SIBLING;
1589
1590 /*
1591 * Only collect the first location as it can reconstruct the
1592 * remaining state by following the instructions.
1593 * start = 0 means it covers the whole range.
1594 */
1595 if (dwarf_getlocations(&attr, 0, &base, &start, &end, &ops, &nops) <= 0)
1596 return DIE_FIND_CB_SIBLING;
1597
1598 if (!check_allowed_ops(ops, nops))
1599 return DIE_FIND_CB_SIBLING;
1600
1601 if (die_get_real_type(die_mem, &type_die) == NULL)
1602 return DIE_FIND_CB_SIBLING;
1603
1604 vt = malloc(sizeof(*vt));
1605 if (vt == NULL)
1606 return DIE_FIND_CB_END;
1607
1608 vt->die_off = dwarf_dieoffset(&type_die);
1609 vt->addr = start;
1610 vt->reg = reg_from_dwarf_op(ops);
1611 vt->offset = offset_from_dwarf_op(ops);
1612 vt->next = *var_types;
1613 *var_types = vt;
1614
1615 return DIE_FIND_CB_SIBLING;
1616}
1617
1618/**
1619 * die_collect_vars - Save all variables and parameters
1620 * @sc_die: a scope DIE
1621 * @var_types: a pointer to save the resulting list
1622 *
1623 * Save all variables and parameters in the @sc_die and save them to @var_types.
1624 * The @var_types is a singly-linked list containing type and location info.
1625 * Actual type can be retrieved using dwarf_offdie() with 'die_off' later.
1626 *
1627 * Callers should free @var_types.
1628 */
1629void die_collect_vars(Dwarf_Die *sc_die, struct die_var_type **var_types)
1630{
1631 Dwarf_Die die_mem;
1632
1633 die_find_child(sc_die, __die_collect_vars_cb, (void *)var_types, &die_mem);
1634}
1635
1636static int __die_collect_global_vars_cb(Dwarf_Die *die_mem, void *arg)
1637{
1638 struct die_var_type **var_types = arg;
1639 Dwarf_Die type_die;
1640 int tag = dwarf_tag(die_mem);
1641 Dwarf_Attribute attr;
1642 Dwarf_Addr base, start, end;
1643 Dwarf_Op *ops;
1644 size_t nops;
1645 struct die_var_type *vt;
1646
1647 if (tag != DW_TAG_variable)
1648 return DIE_FIND_CB_SIBLING;
1649
1650 if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL)
1651 return DIE_FIND_CB_SIBLING;
1652
1653 /* Only collect the location with an absolute address. */
1654 if (dwarf_getlocations(&attr, 0, &base, &start, &end, &ops, &nops) <= 0)
1655 return DIE_FIND_CB_SIBLING;
1656
1657 if (ops->atom != DW_OP_addr)
1658 return DIE_FIND_CB_SIBLING;
1659
1660 if (!check_allowed_ops(ops, nops))
1661 return DIE_FIND_CB_SIBLING;
1662
1663 if (die_get_real_type(die_mem, &type_die) == NULL)
1664 return DIE_FIND_CB_SIBLING;
1665
1666 vt = malloc(sizeof(*vt));
1667 if (vt == NULL)
1668 return DIE_FIND_CB_END;
1669
1670 vt->die_off = dwarf_dieoffset(&type_die);
1671 vt->addr = ops->number;
1672 vt->reg = -1;
1673 vt->offset = 0;
1674 vt->next = *var_types;
1675 *var_types = vt;
1676
1677 return DIE_FIND_CB_SIBLING;
1678}
1679
1680/**
1681 * die_collect_global_vars - Save all global variables
1682 * @cu_die: a CU DIE
1683 * @var_types: a pointer to save the resulting list
1684 *
1685 * Save all global variables in the @cu_die and save them to @var_types.
1686 * The @var_types is a singly-linked list containing type and location info.
1687 * Actual type can be retrieved using dwarf_offdie() with 'die_off' later.
1688 *
1689 * Callers should free @var_types.
1690 */
1691void die_collect_global_vars(Dwarf_Die *cu_die, struct die_var_type **var_types)
1692{
1693 Dwarf_Die die_mem;
1694
1695 die_find_child(cu_die, __die_collect_global_vars_cb, (void *)var_types, &die_mem);
1696}
1697
1698/**
1699 * die_get_cfa - Get frame base information
1700 * @dwarf: a Dwarf info
1701 * @pc: program address
1702 * @preg: pointer for saved register
1703 * @poffset: pointer for saved offset
1704 *
1705 * This function gets register and offset for CFA (Canonical Frame Address)
1706 * by searching the CIE/FDE info. The CFA usually points to the start address
1707 * of the current stack frame and local variables can be located using an offset
1708 * from the CFA. The @preg and @poffset will be updated if it returns 0.
1709 */
1710int die_get_cfa(Dwarf *dwarf, u64 pc, int *preg, int *poffset)
1711{
1712 Dwarf_CFI *cfi;
1713 Dwarf_Frame *frame = NULL;
1714 Dwarf_Op *ops = NULL;
1715 size_t nops;
1716
1717 cfi = dwarf_getcfi(dwarf);
1718 if (cfi == NULL)
1719 return -1;
1720
1721 if (!dwarf_cfi_addrframe(cfi, pc, &frame) &&
1722 !dwarf_frame_cfa(frame, &ops, &nops) &&
1723 check_allowed_ops(ops, nops)) {
1724 *preg = reg_from_dwarf_op(ops);
1725 *poffset = offset_from_dwarf_op(ops);
1726 return 0;
1727 }
1728 return -1;
1729}
1730
1731/*
1732 * die_has_loclist - Check if DW_AT_location of @vr_die is a location list
1733 * @vr_die: a variable DIE
1734 */
1735static bool die_has_loclist(Dwarf_Die *vr_die)
1736{
1737 Dwarf_Attribute loc;
1738 int tag = dwarf_tag(vr_die);
1739
1740 if (tag != DW_TAG_formal_parameter &&
1741 tag != DW_TAG_variable)
1742 return false;
1743
1744 return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
1745 dwarf_whatform(&loc) == DW_FORM_sec_offset);
1746}
1747
1748/*
1749 * die_is_optimized_target - Check if target program is compiled with
1750 * optimization
1751 * @cu_die: a CU DIE
1752 *
1753 * For any object in given CU whose DW_AT_location is a location list,
1754 * target program is compiled with optimization. This is applicable to
1755 * clang as well.
1756 */
1757bool die_is_optimized_target(Dwarf_Die *cu_die)
1758{
1759 Dwarf_Die tmp_die;
1760
1761 if (die_has_loclist(cu_die))
1762 return true;
1763
1764 if (!dwarf_child(cu_die, &tmp_die) &&
1765 die_is_optimized_target(&tmp_die))
1766 return true;
1767
1768 if (!dwarf_siblingof(cu_die, &tmp_die) &&
1769 die_is_optimized_target(&tmp_die))
1770 return true;
1771
1772 return false;
1773}
1774
1775/*
1776 * die_search_idx - Search index of given line address
1777 * @lines: Line records of single CU
1778 * @nr_lines: Number of @lines
1779 * @addr: address we are looking for
1780 * @idx: index to be set by this function (return value)
1781 *
1782 * Search for @addr by looping over every lines of CU. If address
1783 * matches, set index of that line in @idx. Note that single source
1784 * line can have multiple line records. i.e. single source line can
1785 * have multiple index.
1786 */
1787static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
1788 Dwarf_Addr addr, unsigned long *idx)
1789{
1790 unsigned long i;
1791 Dwarf_Addr tmp;
1792
1793 for (i = 0; i < nr_lines; i++) {
1794 if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
1795 return false;
1796
1797 if (tmp == addr) {
1798 *idx = i;
1799 return true;
1800 }
1801 }
1802 return false;
1803}
1804
1805/*
1806 * die_get_postprologue_addr - Search next address after function prologue
1807 * @entrypc_idx: entrypc index
1808 * @lines: Line records of single CU
1809 * @nr_lines: Number of @lines
1810 * @hignpc: high PC address of function
1811 * @postprologue_addr: Next address after function prologue (return value)
1812 *
1813 * Look for prologue-end marker. If there is no explicit marker, return
1814 * address of next line record or next source line.
1815 */
1816static bool die_get_postprologue_addr(unsigned long entrypc_idx,
1817 Dwarf_Lines *lines,
1818 unsigned long nr_lines,
1819 Dwarf_Addr highpc,
1820 Dwarf_Addr *postprologue_addr)
1821{
1822 unsigned long i;
1823 int entrypc_lno, lno;
1824 Dwarf_Line *line;
1825 Dwarf_Addr addr;
1826 bool p_end;
1827
1828 /* entrypc_lno is actual source line number */
1829 line = dwarf_onesrcline(lines, entrypc_idx);
1830 if (dwarf_lineno(line, &entrypc_lno))
1831 return false;
1832
1833 for (i = entrypc_idx; i < nr_lines; i++) {
1834 line = dwarf_onesrcline(lines, i);
1835
1836 if (dwarf_lineaddr(line, &addr) ||
1837 dwarf_lineno(line, &lno) ||
1838 dwarf_lineprologueend(line, &p_end))
1839 return false;
1840
1841 /* highpc is exclusive. [entrypc,highpc) */
1842 if (addr >= highpc)
1843 break;
1844
1845 /* clang supports prologue-end marker */
1846 if (p_end)
1847 break;
1848
1849 /* Actual next line in source */
1850 if (lno != entrypc_lno)
1851 break;
1852
1853 /*
1854 * Single source line can have multiple line records.
1855 * For Example,
1856 * void foo() { printf("hello\n"); }
1857 * contains two line records. One points to declaration and
1858 * other points to printf() line. Variable 'lno' won't get
1859 * incremented in this case but 'i' will.
1860 */
1861 if (i != entrypc_idx)
1862 break;
1863 }
1864
1865 dwarf_lineaddr(line, postprologue_addr);
1866 if (*postprologue_addr >= highpc)
1867 dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
1868 postprologue_addr);
1869
1870 return true;
1871}
1872
1873/*
1874 * die_skip_prologue - Use next address after prologue as probe location
1875 * @sp_die: a subprogram DIE
1876 * @cu_die: a CU DIE
1877 * @entrypc: entrypc of the function
1878 *
1879 * Function prologue prepares stack and registers before executing function
1880 * logic. When target program is compiled without optimization, function
1881 * parameter information is only valid after prologue. When we probe entrypc
1882 * of the function, and try to record function parameter, it contains
1883 * garbage value.
1884 */
1885void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
1886 Dwarf_Addr *entrypc)
1887{
1888 size_t nr_lines = 0;
1889 unsigned long entrypc_idx = 0;
1890 Dwarf_Lines *lines = NULL;
1891 Dwarf_Addr postprologue_addr;
1892 Dwarf_Addr highpc;
1893
1894 if (dwarf_highpc(sp_die, &highpc))
1895 return;
1896
1897 if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
1898 return;
1899
1900 if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
1901 return;
1902
1903 if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
1904 highpc, &postprologue_addr))
1905 return;
1906
1907 *entrypc = postprologue_addr;
1908}
1909
1910/* Internal parameters for __die_find_scope_cb() */
1911struct find_scope_data {
1912 /* Target instruction address */
1913 Dwarf_Addr pc;
1914 /* Number of scopes found [output] */
1915 int nr;
1916 /* Array of scopes found, 0 for the outermost one. [output] */
1917 Dwarf_Die *scopes;
1918};
1919
1920static int __die_find_scope_cb(Dwarf_Die *die_mem, void *arg)
1921{
1922 struct find_scope_data *data = arg;
1923
1924 if (dwarf_haspc(die_mem, data->pc)) {
1925 Dwarf_Die *tmp;
1926
1927 tmp = realloc(data->scopes, (data->nr + 1) * sizeof(*tmp));
1928 if (tmp == NULL)
1929 return DIE_FIND_CB_END;
1930
1931 memcpy(tmp + data->nr, die_mem, sizeof(*die_mem));
1932 data->scopes = tmp;
1933 data->nr++;
1934 return DIE_FIND_CB_CHILD;
1935 }
1936 return DIE_FIND_CB_SIBLING;
1937}
1938
1939/**
1940 * die_get_scopes - Return a list of scopes including the address
1941 * @cu_die: a compile unit DIE
1942 * @pc: the address to find
1943 * @scopes: the array of DIEs for scopes (result)
1944 *
1945 * This function does the same as the dwarf_getscopes() but doesn't follow
1946 * the origins of inlined functions. It returns the number of scopes saved
1947 * in the @scopes argument. The outer scope will be saved first (index 0) and
1948 * the last one is the innermost scope at the @pc.
1949 */
1950int die_get_scopes(Dwarf_Die *cu_die, Dwarf_Addr pc, Dwarf_Die **scopes)
1951{
1952 struct find_scope_data data = {
1953 .pc = pc,
1954 };
1955 Dwarf_Die die_mem;
1956
1957 die_find_child(cu_die, __die_find_scope_cb, &data, &die_mem);
1958
1959 *scopes = data.scopes;
1960 return data.nr;
1961}
1962
1963static int __die_find_member_offset_cb(Dwarf_Die *die_mem, void *arg)
1964{
1965 Dwarf_Die type_die;
1966 Dwarf_Word size, loc;
1967 Dwarf_Word offset = (long)arg;
1968 int tag = dwarf_tag(die_mem);
1969
1970 if (tag != DW_TAG_member)
1971 return DIE_FIND_CB_SIBLING;
1972
1973 /* Unions might not have location */
1974 if (die_get_data_member_location(die_mem, &loc) < 0) {
1975 Dwarf_Attribute attr;
1976
1977 if (dwarf_attr_integrate(die_mem, DW_AT_data_bit_offset, &attr) &&
1978 dwarf_formudata(&attr, &loc) == 0)
1979 loc /= 8;
1980 else
1981 loc = 0;
1982 }
1983
1984 if (offset == loc)
1985 return DIE_FIND_CB_END;
1986
1987 if (die_get_real_type(die_mem, &type_die) == NULL) {
1988 // TODO: add a pr_debug_dtp() later for this unlikely failure
1989 return DIE_FIND_CB_SIBLING;
1990 }
1991
1992 if (dwarf_aggregate_size(&type_die, &size) < 0)
1993 size = 0;
1994
1995 if (loc < offset && offset < (loc + size))
1996 return DIE_FIND_CB_END;
1997
1998 return DIE_FIND_CB_SIBLING;
1999}
2000
2001/**
2002 * die_get_member_type - Return type info of struct member
2003 * @type_die: a type DIE
2004 * @offset: offset in the type
2005 * @die_mem: a buffer to save the resulting DIE
2006 *
2007 * This function returns a type of a member in @type_die where it's located at
2008 * @offset if it's a struct. For now, it just returns the first matching
2009 * member in a union. For other types, it'd return the given type directly
2010 * if it's within the size of the type or NULL otherwise.
2011 */
2012Dwarf_Die *die_get_member_type(Dwarf_Die *type_die, int offset,
2013 Dwarf_Die *die_mem)
2014{
2015 Dwarf_Die *member;
2016 Dwarf_Die mb_type;
2017 int tag;
2018
2019 tag = dwarf_tag(type_die);
2020 /* If it's not a compound type, return the type directly */
2021 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
2022 Dwarf_Word size;
2023
2024 if (dwarf_aggregate_size(type_die, &size) < 0)
2025 size = 0;
2026
2027 if ((unsigned)offset >= size)
2028 return NULL;
2029
2030 *die_mem = *type_die;
2031 return die_mem;
2032 }
2033
2034 mb_type = *type_die;
2035 /* TODO: Handle union types better? */
2036 while (tag == DW_TAG_structure_type || tag == DW_TAG_union_type) {
2037 member = die_find_child(&mb_type, __die_find_member_offset_cb,
2038 (void *)(long)offset, die_mem);
2039 if (member == NULL)
2040 return NULL;
2041
2042 if (die_get_real_type(member, &mb_type) == NULL)
2043 return NULL;
2044
2045 tag = dwarf_tag(&mb_type);
2046
2047 if (tag == DW_TAG_structure_type || tag == DW_TAG_union_type) {
2048 Dwarf_Word loc;
2049
2050 /* Update offset for the start of the member struct */
2051 if (die_get_data_member_location(member, &loc) == 0)
2052 offset -= loc;
2053 }
2054 }
2055 *die_mem = mb_type;
2056 return die_mem;
2057}
2058
2059/**
2060 * die_deref_ptr_type - Return type info for pointer access
2061 * @ptr_die: a pointer type DIE
2062 * @offset: access offset for the pointer
2063 * @die_mem: a buffer to save the resulting DIE
2064 *
2065 * This function follows the pointer in @ptr_die with given @offset
2066 * and saves the resulting type in @die_mem. If the pointer points
2067 * a struct type, actual member at the offset would be returned.
2068 */
2069Dwarf_Die *die_deref_ptr_type(Dwarf_Die *ptr_die, int offset,
2070 Dwarf_Die *die_mem)
2071{
2072 Dwarf_Die type_die;
2073
2074 if (dwarf_tag(ptr_die) != DW_TAG_pointer_type)
2075 return NULL;
2076
2077 if (die_get_real_type(ptr_die, &type_die) == NULL)
2078 return NULL;
2079
2080 return die_get_member_type(&type_die, offset, die_mem);
2081}