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 */
cu_find_realpath(Dwarf_Die * cu_die,const char * fname)22 const 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 */
cu_get_comp_dir(Dwarf_Die * cu_die)54 const 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 /* Unlike dwarf_getsrc_die(), cu_getsrc_die() only returns statement line */
cu_getsrc_die(Dwarf_Die * cu_die,Dwarf_Addr addr)63 static Dwarf_Line *cu_getsrc_die(Dwarf_Die *cu_die, Dwarf_Addr addr)
64 {
65 Dwarf_Addr laddr;
66 Dwarf_Lines *lines;
67 Dwarf_Line *line;
68 size_t nlines, l, u, n;
69 bool flag;
70
71 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0 ||
72 nlines == 0)
73 return NULL;
74
75 /* Lines are sorted by address, use binary search */
76 l = 0; u = nlines - 1;
77 while (l < u) {
78 n = u - (u - l) / 2;
79 line = dwarf_onesrcline(lines, n);
80 if (!line || dwarf_lineaddr(line, &laddr) != 0)
81 return NULL;
82 if (addr < laddr)
83 u = n - 1;
84 else
85 l = n;
86 }
87 /* Going backward to find the lowest line */
88 do {
89 line = dwarf_onesrcline(lines, --l);
90 if (!line || dwarf_lineaddr(line, &laddr) != 0)
91 return NULL;
92 } while (laddr == addr);
93 l++;
94 /* Going forward to find the statement line */
95 do {
96 line = dwarf_onesrcline(lines, l++);
97 if (!line || dwarf_lineaddr(line, &laddr) != 0 ||
98 dwarf_linebeginstatement(line, &flag) != 0)
99 return NULL;
100 if (laddr > addr)
101 return NULL;
102 } while (!flag);
103
104 return line;
105 }
106
107 /**
108 * cu_find_lineinfo - Get a line number and file name for given address
109 * @cu_die: a CU DIE
110 * @addr: An address
111 * @fname: a pointer which returns the file name string
112 * @lineno: a pointer which returns the line number
113 *
114 * Find a line number and file name for @addr in @cu_die.
115 */
cu_find_lineinfo(Dwarf_Die * cu_die,Dwarf_Addr addr,const char ** fname,int * lineno)116 int cu_find_lineinfo(Dwarf_Die *cu_die, Dwarf_Addr addr,
117 const char **fname, int *lineno)
118 {
119 Dwarf_Line *line;
120 Dwarf_Die die_mem;
121 Dwarf_Addr faddr;
122
123 if (die_find_realfunc(cu_die, addr, &die_mem)
124 && die_entrypc(&die_mem, &faddr) == 0 &&
125 faddr == addr) {
126 *fname = die_get_decl_file(&die_mem);
127 dwarf_decl_line(&die_mem, lineno);
128 goto out;
129 }
130
131 line = cu_getsrc_die(cu_die, addr);
132 if (line && dwarf_lineno(line, lineno) == 0) {
133 *fname = dwarf_linesrc(line, NULL, NULL);
134 if (!*fname)
135 /* line number is useless without filename */
136 *lineno = 0;
137 }
138
139 out:
140 return (*lineno && *fname) ? *lineno : -ENOENT;
141 }
142
143 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
144
145 /**
146 * cu_walk_functions_at - Walk on function DIEs at given address
147 * @cu_die: A CU DIE
148 * @addr: An address
149 * @callback: A callback which called with found DIEs
150 * @data: A user data
151 *
152 * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
153 * should be subprogram or inlined-subroutines.
154 */
cu_walk_functions_at(Dwarf_Die * cu_die,Dwarf_Addr addr,int (* callback)(Dwarf_Die *,void *),void * data)155 int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
156 int (*callback)(Dwarf_Die *, void *), void *data)
157 {
158 Dwarf_Die die_mem;
159 Dwarf_Die *sc_die;
160 int ret = -ENOENT;
161
162 /* Inlined function could be recursive. Trace it until fail */
163 for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
164 sc_die != NULL;
165 sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
166 &die_mem)) {
167 ret = callback(sc_die, data);
168 if (ret)
169 break;
170 }
171
172 return ret;
173
174 }
175
176 /**
177 * die_get_linkage_name - Get the linkage name of the object
178 * @dw_die: A DIE of the object
179 *
180 * Get the linkage name attribute of given @dw_die.
181 * For C++ binary, the linkage name will be the mangled symbol.
182 */
die_get_linkage_name(Dwarf_Die * dw_die)183 const char *die_get_linkage_name(Dwarf_Die *dw_die)
184 {
185 Dwarf_Attribute attr;
186
187 if (dwarf_attr_integrate(dw_die, DW_AT_linkage_name, &attr) == NULL)
188 return NULL;
189 return dwarf_formstring(&attr);
190 }
191
192 /**
193 * die_compare_name - Compare diename and tname
194 * @dw_die: a DIE
195 * @tname: a string of target name
196 *
197 * Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
198 */
die_compare_name(Dwarf_Die * dw_die,const char * tname)199 bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
200 {
201 const char *name;
202
203 name = dwarf_diename(dw_die);
204 return name ? (strcmp(tname, name) == 0) : false;
205 }
206
207 /**
208 * die_match_name - Match diename/linkage name and glob
209 * @dw_die: a DIE
210 * @glob: a string of target glob pattern
211 *
212 * Glob matching the name of @dw_die and @glob. Return false if matching fail.
213 * This also match linkage name.
214 */
die_match_name(Dwarf_Die * dw_die,const char * glob)215 bool die_match_name(Dwarf_Die *dw_die, const char *glob)
216 {
217 const char *name;
218
219 name = dwarf_diename(dw_die);
220 if (name && strglobmatch(name, glob))
221 return true;
222 /* fall back to check linkage name */
223 name = die_get_linkage_name(dw_die);
224 if (name && strglobmatch(name, glob))
225 return true;
226
227 return false;
228 }
229
230 /**
231 * die_get_call_lineno - Get callsite line number of inline-function instance
232 * @in_die: a DIE of an inlined function instance
233 *
234 * Get call-site line number of @in_die. This means from where the inline
235 * function is called.
236 */
die_get_call_lineno(Dwarf_Die * in_die)237 int die_get_call_lineno(Dwarf_Die *in_die)
238 {
239 Dwarf_Attribute attr;
240 Dwarf_Word ret;
241
242 if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
243 return -ENOENT;
244
245 dwarf_formudata(&attr, &ret);
246 return (int)ret;
247 }
248
249 /**
250 * die_get_type - Get type DIE
251 * @vr_die: a DIE of a variable
252 * @die_mem: where to store a type DIE
253 *
254 * Get a DIE of the type of given variable (@vr_die), and store
255 * it to die_mem. Return NULL if fails to get a type DIE.
256 */
die_get_type(Dwarf_Die * vr_die,Dwarf_Die * die_mem)257 Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
258 {
259 Dwarf_Attribute attr;
260
261 if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
262 dwarf_formref_die(&attr, die_mem))
263 return die_mem;
264 else
265 return NULL;
266 }
267
268 /* Get a type die, but skip qualifiers */
__die_get_real_type(Dwarf_Die * vr_die,Dwarf_Die * die_mem)269 static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
270 {
271 int tag;
272
273 do {
274 vr_die = die_get_type(vr_die, die_mem);
275 if (!vr_die)
276 break;
277 tag = dwarf_tag(vr_die);
278 } while (tag == DW_TAG_const_type ||
279 tag == DW_TAG_restrict_type ||
280 tag == DW_TAG_volatile_type ||
281 tag == DW_TAG_shared_type);
282
283 return vr_die;
284 }
285
286 /**
287 * die_get_real_type - Get a type die, but skip qualifiers and typedef
288 * @vr_die: a DIE of a variable
289 * @die_mem: where to store a type DIE
290 *
291 * Get a DIE of the type of given variable (@vr_die), and store
292 * it to die_mem. Return NULL if fails to get a type DIE.
293 * If the type is qualifiers (e.g. const) or typedef, this skips it
294 * and tries to find real type (structure or basic types, e.g. int).
295 */
die_get_real_type(Dwarf_Die * vr_die,Dwarf_Die * die_mem)296 Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
297 {
298 do {
299 vr_die = __die_get_real_type(vr_die, die_mem);
300 } while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
301
302 return vr_die;
303 }
304
305 /* Get attribute and translate it as a udata */
die_get_attr_udata(Dwarf_Die * tp_die,unsigned int attr_name,Dwarf_Word * result)306 static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
307 Dwarf_Word *result)
308 {
309 Dwarf_Attribute attr;
310
311 if (dwarf_attr_integrate(tp_die, attr_name, &attr) == NULL ||
312 dwarf_formudata(&attr, result) != 0)
313 return -ENOENT;
314
315 return 0;
316 }
317
318 /**
319 * die_is_signed_type - Check whether a type DIE is signed or not
320 * @tp_die: a DIE of a type
321 *
322 * Get the encoding of @tp_die and return true if the encoding
323 * is signed.
324 */
die_is_signed_type(Dwarf_Die * tp_die)325 bool die_is_signed_type(Dwarf_Die *tp_die)
326 {
327 Dwarf_Word ret;
328
329 if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
330 return false;
331
332 return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
333 ret == DW_ATE_signed_fixed);
334 }
335
336 /**
337 * die_is_func_def - Ensure that this DIE is a subprogram and definition
338 * @dw_die: a DIE
339 *
340 * Ensure that this DIE is a subprogram and NOT a declaration. This
341 * returns true if @dw_die is a function definition.
342 **/
die_is_func_def(Dwarf_Die * dw_die)343 bool die_is_func_def(Dwarf_Die *dw_die)
344 {
345 Dwarf_Attribute attr;
346 Dwarf_Addr addr = 0;
347
348 if (dwarf_tag(dw_die) != DW_TAG_subprogram)
349 return false;
350
351 if (dwarf_attr(dw_die, DW_AT_declaration, &attr))
352 return false;
353
354 /*
355 * DW_AT_declaration can be lost from function declaration
356 * by gcc's bug #97060.
357 * So we need to check this subprogram DIE has DW_AT_inline
358 * or an entry address.
359 */
360 if (!dwarf_attr(dw_die, DW_AT_inline, &attr) &&
361 die_entrypc(dw_die, &addr) < 0)
362 return false;
363
364 return true;
365 }
366
367 /**
368 * die_entrypc - Returns entry PC (the lowest address) of a DIE
369 * @dw_die: a DIE
370 * @addr: where to store entry PC
371 *
372 * Since dwarf_entrypc() does not return entry PC if the DIE has only address
373 * range, we have to use this to retrieve the lowest address from the address
374 * range attribute.
375 */
die_entrypc(Dwarf_Die * dw_die,Dwarf_Addr * addr)376 int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)
377 {
378 Dwarf_Addr base, end;
379 Dwarf_Attribute attr;
380
381 if (!addr)
382 return -EINVAL;
383
384 if (dwarf_entrypc(dw_die, addr) == 0)
385 return 0;
386
387 /*
388 * Since the dwarf_ranges() will return 0 if there is no
389 * DW_AT_ranges attribute, we should check it first.
390 */
391 if (!dwarf_attr(dw_die, DW_AT_ranges, &attr))
392 return -ENOENT;
393
394 return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;
395 }
396
397 /**
398 * die_is_func_instance - Ensure that this DIE is an instance of a subprogram
399 * @dw_die: a DIE
400 *
401 * Ensure that this DIE is an instance (which has an entry address).
402 * This returns true if @dw_die is a function instance. If not, the @dw_die
403 * must be a prototype. You can use die_walk_instances() to find actual
404 * instances.
405 **/
die_is_func_instance(Dwarf_Die * dw_die)406 bool die_is_func_instance(Dwarf_Die *dw_die)
407 {
408 Dwarf_Addr tmp;
409 Dwarf_Attribute attr_mem;
410 int tag = dwarf_tag(dw_die);
411
412 if (tag != DW_TAG_subprogram &&
413 tag != DW_TAG_inlined_subroutine)
414 return false;
415
416 return dwarf_entrypc(dw_die, &tmp) == 0 ||
417 dwarf_attr(dw_die, DW_AT_ranges, &attr_mem) != NULL;
418 }
419
420 /**
421 * die_get_data_member_location - Get the data-member offset
422 * @mb_die: a DIE of a member of a data structure
423 * @offs: The offset of the member in the data structure
424 *
425 * Get the offset of @mb_die in the data structure including @mb_die, and
426 * stores result offset to @offs. If any error occurs this returns errno.
427 */
die_get_data_member_location(Dwarf_Die * mb_die,Dwarf_Word * offs)428 int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
429 {
430 Dwarf_Attribute attr;
431 Dwarf_Op *expr;
432 size_t nexpr;
433 int ret;
434
435 if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
436 return -ENOENT;
437
438 if (dwarf_formudata(&attr, offs) != 0) {
439 /* DW_AT_data_member_location should be DW_OP_plus_uconst */
440 ret = dwarf_getlocation(&attr, &expr, &nexpr);
441 if (ret < 0 || nexpr == 0)
442 return -ENOENT;
443
444 if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
445 pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
446 expr[0].atom, nexpr);
447 return -ENOTSUP;
448 }
449 *offs = (Dwarf_Word)expr[0].number;
450 }
451 return 0;
452 }
453
454 /* Get the call file index number in CU DIE */
die_get_call_fileno(Dwarf_Die * in_die)455 static int die_get_call_fileno(Dwarf_Die *in_die)
456 {
457 Dwarf_Word idx;
458
459 if (die_get_attr_udata(in_die, DW_AT_call_file, &idx) == 0)
460 return (int)idx;
461 else
462 return -ENOENT;
463 }
464
465 /* Get the declared file index number in CU DIE */
die_get_decl_fileno(Dwarf_Die * pdie)466 static int die_get_decl_fileno(Dwarf_Die *pdie)
467 {
468 Dwarf_Word idx;
469
470 if (die_get_attr_udata(pdie, DW_AT_decl_file, &idx) == 0)
471 return (int)idx;
472 else
473 return -ENOENT;
474 }
475
476 /* Return the file name by index */
die_get_file_name(Dwarf_Die * dw_die,int idx)477 static const char *die_get_file_name(Dwarf_Die *dw_die, int idx)
478 {
479 Dwarf_Die cu_die;
480 Dwarf_Files *files;
481 Dwarf_Attribute attr_mem;
482
483 if (idx < 0 || !dwarf_attr_integrate(dw_die, DW_AT_decl_file, &attr_mem) ||
484 !dwarf_cu_die(attr_mem.cu, &cu_die, NULL, NULL, NULL, NULL, NULL, NULL) ||
485 dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
486 return NULL;
487
488 return dwarf_filesrc(files, idx, NULL, NULL);
489 }
490
491 /**
492 * die_get_call_file - Get callsite file name of inlined function instance
493 * @in_die: a DIE of an inlined function instance
494 *
495 * Get call-site file name of @in_die. This means from which file the inline
496 * function is called.
497 */
die_get_call_file(Dwarf_Die * in_die)498 const char *die_get_call_file(Dwarf_Die *in_die)
499 {
500 return die_get_file_name(in_die, die_get_call_fileno(in_die));
501 }
502
503 /**
504 * die_get_decl_file - Find the declared file name of this DIE
505 * @dw_die: a DIE for something declared.
506 *
507 * Get declared file name of @dw_die.
508 * NOTE: Since some version of clang DWARF5 implementation incorrectly uses
509 * file index 0 for DW_AT_decl_file, die_get_decl_file() will return NULL for
510 * such cases. Use this function instead.
511 */
die_get_decl_file(Dwarf_Die * dw_die)512 const char *die_get_decl_file(Dwarf_Die *dw_die)
513 {
514 return die_get_file_name(dw_die, die_get_decl_fileno(dw_die));
515 }
516
517 /**
518 * die_find_child - Generic DIE search function in DIE tree
519 * @rt_die: a root DIE
520 * @callback: a callback function
521 * @data: a user data passed to the callback function
522 * @die_mem: a buffer for result DIE
523 *
524 * Trace DIE tree from @rt_die and call @callback for each child DIE.
525 * If @callback returns DIE_FIND_CB_END, this stores the DIE into
526 * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
527 * this continues to trace the tree. Optionally, @callback can return
528 * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
529 * the children and trace only the siblings respectively.
530 * Returns NULL if @callback can't find any appropriate DIE.
531 */
die_find_child(Dwarf_Die * rt_die,int (* callback)(Dwarf_Die *,void *),void * data,Dwarf_Die * die_mem)532 Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
533 int (*callback)(Dwarf_Die *, void *),
534 void *data, Dwarf_Die *die_mem)
535 {
536 Dwarf_Die child_die;
537 int ret;
538
539 ret = dwarf_child(rt_die, die_mem);
540 if (ret != 0)
541 return NULL;
542
543 do {
544 ret = callback(die_mem, data);
545 if (ret == DIE_FIND_CB_END)
546 return die_mem;
547
548 if ((ret & DIE_FIND_CB_CHILD) &&
549 die_find_child(die_mem, callback, data, &child_die)) {
550 memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
551 return die_mem;
552 }
553 } while ((ret & DIE_FIND_CB_SIBLING) &&
554 dwarf_siblingof(die_mem, die_mem) == 0);
555
556 return NULL;
557 }
558
559 struct __addr_die_search_param {
560 Dwarf_Addr addr;
561 Dwarf_Die *die_mem;
562 };
563
__die_search_func_tail_cb(Dwarf_Die * fn_die,void * data)564 static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
565 {
566 struct __addr_die_search_param *ad = data;
567 Dwarf_Addr addr = 0;
568
569 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
570 !dwarf_highpc(fn_die, &addr) &&
571 addr == ad->addr) {
572 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
573 return DWARF_CB_ABORT;
574 }
575 return DWARF_CB_OK;
576 }
577
578 /**
579 * die_find_tailfunc - Search for a non-inlined function with tail call at
580 * given address
581 * @cu_die: a CU DIE which including @addr
582 * @addr: target address
583 * @die_mem: a buffer for result DIE
584 *
585 * Search for a non-inlined function DIE with tail call at @addr. Stores the
586 * DIE to @die_mem and returns it if found. Returns NULL if failed.
587 */
die_find_tailfunc(Dwarf_Die * cu_die,Dwarf_Addr addr,Dwarf_Die * die_mem)588 Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
589 Dwarf_Die *die_mem)
590 {
591 struct __addr_die_search_param ad;
592 ad.addr = addr;
593 ad.die_mem = die_mem;
594 /* dwarf_getscopes can't find subprogram. */
595 if (!dwarf_getfuncs(cu_die, __die_search_func_tail_cb, &ad, 0))
596 return NULL;
597 else
598 return die_mem;
599 }
600
601 /* die_find callback for non-inlined function search */
__die_search_func_cb(Dwarf_Die * fn_die,void * data)602 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
603 {
604 struct __addr_die_search_param *ad = data;
605
606 /*
607 * Since a declaration entry doesn't has given pc, this always returns
608 * function definition entry.
609 */
610 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
611 dwarf_haspc(fn_die, ad->addr)) {
612 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
613 return DWARF_CB_ABORT;
614 }
615 return DWARF_CB_OK;
616 }
617
618 /**
619 * die_find_realfunc - Search a non-inlined function at given address
620 * @cu_die: a CU DIE which including @addr
621 * @addr: target address
622 * @die_mem: a buffer for result DIE
623 *
624 * Search a non-inlined function DIE which includes @addr. Stores the
625 * DIE to @die_mem and returns it if found. Returns NULL if failed.
626 */
die_find_realfunc(Dwarf_Die * cu_die,Dwarf_Addr addr,Dwarf_Die * die_mem)627 Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
628 Dwarf_Die *die_mem)
629 {
630 struct __addr_die_search_param ad;
631 ad.addr = addr;
632 ad.die_mem = die_mem;
633 /* dwarf_getscopes can't find subprogram. */
634 if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
635 return NULL;
636 else
637 return die_mem;
638 }
639
640 /* die_find callback for inline function search */
__die_find_inline_cb(Dwarf_Die * die_mem,void * data)641 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
642 {
643 Dwarf_Addr *addr = data;
644
645 if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
646 dwarf_haspc(die_mem, *addr))
647 return DIE_FIND_CB_END;
648
649 return DIE_FIND_CB_CONTINUE;
650 }
651
652 /**
653 * die_find_top_inlinefunc - Search the top inlined function at given address
654 * @sp_die: a subprogram DIE which including @addr
655 * @addr: target address
656 * @die_mem: a buffer for result DIE
657 *
658 * Search an inlined function DIE which includes @addr. Stores the
659 * DIE to @die_mem and returns it if found. Returns NULL if failed.
660 * Even if several inlined functions are expanded recursively, this
661 * doesn't trace it down, and returns the topmost one.
662 */
die_find_top_inlinefunc(Dwarf_Die * sp_die,Dwarf_Addr addr,Dwarf_Die * die_mem)663 Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
664 Dwarf_Die *die_mem)
665 {
666 return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
667 }
668
669 /**
670 * die_find_inlinefunc - Search an inlined function at given address
671 * @sp_die: a subprogram DIE which including @addr
672 * @addr: target address
673 * @die_mem: a buffer for result DIE
674 *
675 * Search an inlined function DIE which includes @addr. Stores the
676 * DIE to @die_mem and returns it if found. Returns NULL if failed.
677 * If several inlined functions are expanded recursively, this trace
678 * it down and returns deepest one.
679 */
die_find_inlinefunc(Dwarf_Die * sp_die,Dwarf_Addr addr,Dwarf_Die * die_mem)680 Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
681 Dwarf_Die *die_mem)
682 {
683 Dwarf_Die tmp_die;
684
685 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
686 if (!sp_die)
687 return NULL;
688
689 /* Inlined function could be recursive. Trace it until fail */
690 while (sp_die) {
691 memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
692 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
693 &tmp_die);
694 }
695
696 return die_mem;
697 }
698
699 struct __instance_walk_param {
700 void *addr;
701 int (*callback)(Dwarf_Die *, void *);
702 void *data;
703 int retval;
704 };
705
__die_walk_instances_cb(Dwarf_Die * inst,void * data)706 static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
707 {
708 struct __instance_walk_param *iwp = data;
709 Dwarf_Attribute attr_mem;
710 Dwarf_Die origin_mem;
711 Dwarf_Attribute *attr;
712 Dwarf_Die *origin;
713 int tmp;
714
715 if (!die_is_func_instance(inst))
716 return DIE_FIND_CB_CONTINUE;
717
718 attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
719 if (attr == NULL)
720 return DIE_FIND_CB_CONTINUE;
721
722 origin = dwarf_formref_die(attr, &origin_mem);
723 if (origin == NULL || origin->addr != iwp->addr)
724 return DIE_FIND_CB_CONTINUE;
725
726 /* Ignore redundant instances */
727 if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
728 dwarf_decl_line(origin, &tmp);
729 if (die_get_call_lineno(inst) == tmp) {
730 tmp = die_get_decl_fileno(origin);
731 if (die_get_call_fileno(inst) == tmp)
732 return DIE_FIND_CB_CONTINUE;
733 }
734 }
735
736 iwp->retval = iwp->callback(inst, iwp->data);
737
738 return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
739 }
740
741 /**
742 * die_walk_instances - Walk on instances of given DIE
743 * @or_die: an abstract original DIE
744 * @callback: a callback function which is called with instance DIE
745 * @data: user data
746 *
747 * Walk on the instances of give @in_die. @in_die must be an inlined function
748 * declaration. This returns the return value of @callback if it returns
749 * non-zero value, or -ENOENT if there is no instance.
750 */
die_walk_instances(Dwarf_Die * or_die,int (* callback)(Dwarf_Die *,void *),void * data)751 int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
752 void *data)
753 {
754 Dwarf_Die cu_die;
755 Dwarf_Die die_mem;
756 struct __instance_walk_param iwp = {
757 .addr = or_die->addr,
758 .callback = callback,
759 .data = data,
760 .retval = -ENOENT,
761 };
762
763 if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
764 return -ENOENT;
765
766 die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
767
768 return iwp.retval;
769 }
770
771 /* Line walker internal parameters */
772 struct __line_walk_param {
773 bool recursive;
774 line_walk_callback_t callback;
775 void *data;
776 int retval;
777 };
778
__die_walk_funclines_cb(Dwarf_Die * in_die,void * data)779 static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
780 {
781 struct __line_walk_param *lw = data;
782 Dwarf_Addr addr = 0;
783 const char *fname;
784 int lineno;
785
786 if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
787 fname = die_get_call_file(in_die);
788 lineno = die_get_call_lineno(in_die);
789 if (fname && lineno > 0 && die_entrypc(in_die, &addr) == 0) {
790 lw->retval = lw->callback(fname, lineno, addr, lw->data);
791 if (lw->retval != 0)
792 return DIE_FIND_CB_END;
793 }
794 if (!lw->recursive)
795 return DIE_FIND_CB_SIBLING;
796 }
797
798 if (addr) {
799 fname = die_get_decl_file(in_die);
800 if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
801 lw->retval = lw->callback(fname, lineno, addr, lw->data);
802 if (lw->retval != 0)
803 return DIE_FIND_CB_END;
804 }
805 }
806
807 /* Continue to search nested inlined function call-sites */
808 return DIE_FIND_CB_CONTINUE;
809 }
810
811 /* Walk on lines of blocks included in given DIE */
__die_walk_funclines(Dwarf_Die * sp_die,bool recursive,line_walk_callback_t callback,void * data)812 static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
813 line_walk_callback_t callback, void *data)
814 {
815 struct __line_walk_param lw = {
816 .recursive = recursive,
817 .callback = callback,
818 .data = data,
819 .retval = 0,
820 };
821 Dwarf_Die die_mem;
822 Dwarf_Addr addr;
823 const char *fname;
824 int lineno;
825
826 /* Handle function declaration line */
827 fname = die_get_decl_file(sp_die);
828 if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
829 die_entrypc(sp_die, &addr) == 0) {
830 lw.retval = callback(fname, lineno, addr, data);
831 if (lw.retval != 0)
832 goto done;
833 }
834 die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
835 done:
836 return lw.retval;
837 }
838
__die_walk_culines_cb(Dwarf_Die * sp_die,void * data)839 static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
840 {
841 struct __line_walk_param *lw = data;
842
843 /*
844 * Since inlined function can include another inlined function in
845 * the same file, we need to walk in it recursively.
846 */
847 lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
848 if (lw->retval != 0)
849 return DWARF_CB_ABORT;
850
851 return DWARF_CB_OK;
852 }
853
854 /**
855 * die_walk_lines - Walk on lines inside given DIE
856 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
857 * @callback: callback routine
858 * @data: user data
859 *
860 * Walk on all lines inside given @rt_die and call @callback on each line.
861 * If the @rt_die is a function, walk only on the lines inside the function,
862 * otherwise @rt_die must be a CU DIE.
863 * Note that this walks not only dwarf line list, but also function entries
864 * and inline call-site.
865 */
die_walk_lines(Dwarf_Die * rt_die,line_walk_callback_t callback,void * data)866 int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
867 {
868 Dwarf_Lines *lines;
869 Dwarf_Line *line;
870 Dwarf_Addr addr;
871 const char *fname, *decf = NULL, *inf = NULL;
872 int lineno, ret = 0;
873 int decl = 0, inl;
874 Dwarf_Die die_mem, *cu_die;
875 size_t nlines, i;
876 bool flag;
877
878 /* Get the CU die */
879 if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
880 cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
881 dwarf_decl_line(rt_die, &decl);
882 decf = die_get_decl_file(rt_die);
883 if (!decf) {
884 pr_debug2("Failed to get the declared file name of %s\n",
885 dwarf_diename(rt_die));
886 return -EINVAL;
887 }
888 } else
889 cu_die = rt_die;
890 if (!cu_die) {
891 pr_debug2("Failed to get CU from given DIE.\n");
892 return -EINVAL;
893 }
894
895 /* Get lines list in the CU */
896 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
897 pr_debug2("Failed to get source lines on this CU.\n");
898 return -ENOENT;
899 }
900 pr_debug2("Get %zd lines from this CU\n", nlines);
901
902 /* Walk on the lines on lines list */
903 for (i = 0; i < nlines; i++) {
904 line = dwarf_onesrcline(lines, i);
905 if (line == NULL ||
906 dwarf_lineno(line, &lineno) != 0 ||
907 dwarf_lineaddr(line, &addr) != 0) {
908 pr_debug2("Failed to get line info. "
909 "Possible error in debuginfo.\n");
910 continue;
911 }
912 /* Skip end-of-sequence */
913 if (dwarf_lineendsequence(line, &flag) != 0 || flag)
914 continue;
915 /* Skip Non statement line-info */
916 if (dwarf_linebeginstatement(line, &flag) != 0 || !flag)
917 continue;
918 /* Filter lines based on address */
919 if (rt_die != cu_die) {
920 /*
921 * Address filtering
922 * The line is included in given function, and
923 * no inline block includes it.
924 */
925 if (!dwarf_haspc(rt_die, addr))
926 continue;
927
928 if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
929 /* Call-site check */
930 inf = die_get_call_file(&die_mem);
931 if ((inf && !strcmp(inf, decf)) &&
932 die_get_call_lineno(&die_mem) == lineno)
933 goto found;
934
935 dwarf_decl_line(&die_mem, &inl);
936 if (inl != decl ||
937 decf != die_get_decl_file(&die_mem))
938 continue;
939 }
940 }
941 found:
942 /* Get source line */
943 fname = dwarf_linesrc(line, NULL, NULL);
944
945 ret = callback(fname, lineno, addr, data);
946 if (ret != 0)
947 return ret;
948 }
949
950 /*
951 * Dwarf lines doesn't include function declarations and inlined
952 * subroutines. We have to check functions list or given function.
953 */
954 if (rt_die != cu_die)
955 /*
956 * Don't need walk inlined functions recursively, because
957 * inner inlined functions don't have the lines of the
958 * specified function.
959 */
960 ret = __die_walk_funclines(rt_die, false, callback, data);
961 else {
962 struct __line_walk_param param = {
963 .callback = callback,
964 .data = data,
965 .retval = 0,
966 };
967 dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
968 ret = param.retval;
969 }
970
971 return ret;
972 }
973
974 struct __find_variable_param {
975 const char *name;
976 Dwarf_Addr addr;
977 };
978
__die_find_variable_cb(Dwarf_Die * die_mem,void * data)979 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
980 {
981 struct __find_variable_param *fvp = data;
982 Dwarf_Attribute attr;
983 int tag;
984
985 tag = dwarf_tag(die_mem);
986 if ((tag == DW_TAG_formal_parameter ||
987 tag == DW_TAG_variable) &&
988 die_compare_name(die_mem, fvp->name) &&
989 /*
990 * Does the DIE have location information or const value
991 * or external instance?
992 */
993 (dwarf_attr(die_mem, DW_AT_external, &attr) ||
994 dwarf_attr(die_mem, DW_AT_location, &attr) ||
995 dwarf_attr(die_mem, DW_AT_const_value, &attr)))
996 return DIE_FIND_CB_END;
997 if (dwarf_haspc(die_mem, fvp->addr))
998 return DIE_FIND_CB_CONTINUE;
999 else
1000 return DIE_FIND_CB_SIBLING;
1001 }
1002
1003 /**
1004 * die_find_variable_at - Find a given name variable at given address
1005 * @sp_die: a function DIE
1006 * @name: variable name
1007 * @addr: address
1008 * @die_mem: a buffer for result DIE
1009 *
1010 * Find a variable DIE called @name at @addr in @sp_die.
1011 */
die_find_variable_at(Dwarf_Die * sp_die,const char * name,Dwarf_Addr addr,Dwarf_Die * die_mem)1012 Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
1013 Dwarf_Addr addr, Dwarf_Die *die_mem)
1014 {
1015 struct __find_variable_param fvp = { .name = name, .addr = addr};
1016
1017 return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
1018 die_mem);
1019 }
1020
__die_find_member_cb(Dwarf_Die * die_mem,void * data)1021 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
1022 {
1023 const char *name = data;
1024
1025 if (dwarf_tag(die_mem) == DW_TAG_member) {
1026 if (die_compare_name(die_mem, name))
1027 return DIE_FIND_CB_END;
1028 else if (!dwarf_diename(die_mem)) { /* Unnamed structure */
1029 Dwarf_Die type_die, tmp_die;
1030 if (die_get_type(die_mem, &type_die) &&
1031 die_find_member(&type_die, name, &tmp_die))
1032 return DIE_FIND_CB_END;
1033 }
1034 }
1035 return DIE_FIND_CB_SIBLING;
1036 }
1037
1038 /**
1039 * die_find_member - Find a given name member in a data structure
1040 * @st_die: a data structure type DIE
1041 * @name: member name
1042 * @die_mem: a buffer for result DIE
1043 *
1044 * Find a member DIE called @name in @st_die.
1045 */
die_find_member(Dwarf_Die * st_die,const char * name,Dwarf_Die * die_mem)1046 Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
1047 Dwarf_Die *die_mem)
1048 {
1049 return die_find_child(st_die, __die_find_member_cb, (void *)name,
1050 die_mem);
1051 }
1052
1053 /**
1054 * die_get_typename - Get the name of given variable DIE
1055 * @vr_die: a variable DIE
1056 * @buf: a strbuf for result type name
1057 *
1058 * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
1059 * and Return -ENOENT if failed to find type name.
1060 * Note that the result will stores typedef name if possible, and stores
1061 * "*(function_type)" if the type is a function pointer.
1062 */
die_get_typename(Dwarf_Die * vr_die,struct strbuf * buf)1063 int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
1064 {
1065 Dwarf_Die type;
1066 int tag, ret;
1067 const char *tmp = "";
1068
1069 if (__die_get_real_type(vr_die, &type) == NULL)
1070 return -ENOENT;
1071
1072 tag = dwarf_tag(&type);
1073 if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
1074 tmp = "*";
1075 else if (tag == DW_TAG_subroutine_type) {
1076 /* Function pointer */
1077 return strbuf_add(buf, "(function_type)", 15);
1078 } else {
1079 const char *name = dwarf_diename(&type);
1080
1081 if (tag == DW_TAG_union_type)
1082 tmp = "union ";
1083 else if (tag == DW_TAG_structure_type)
1084 tmp = "struct ";
1085 else if (tag == DW_TAG_enumeration_type)
1086 tmp = "enum ";
1087 else if (name == NULL)
1088 return -ENOENT;
1089 /* Write a base name */
1090 return strbuf_addf(buf, "%s%s", tmp, name ?: "");
1091 }
1092 ret = die_get_typename(&type, buf);
1093 return ret ? ret : strbuf_addstr(buf, tmp);
1094 }
1095
1096 /**
1097 * die_get_varname - Get the name and type of given variable DIE
1098 * @vr_die: a variable DIE
1099 * @buf: a strbuf for type and variable name
1100 *
1101 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
1102 */
die_get_varname(Dwarf_Die * vr_die,struct strbuf * buf)1103 int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
1104 {
1105 int ret;
1106
1107 ret = die_get_typename(vr_die, buf);
1108 if (ret < 0) {
1109 pr_debug("Failed to get type, make it unknown.\n");
1110 ret = strbuf_add(buf, "(unknown_type)", 14);
1111 }
1112
1113 return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
1114 }
1115
1116 #ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT
1117 /**
1118 * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
1119 * @sp_die: a subprogram DIE
1120 * @vr_die: a variable DIE
1121 * @buf: a strbuf for variable byte offset range
1122 *
1123 * Get the innermost scope range of @vr_die and stores it in @buf as
1124 * "@<function_name+[NN-NN,NN-NN]>".
1125 */
die_get_var_innermost_scope(Dwarf_Die * sp_die,Dwarf_Die * vr_die,struct strbuf * buf)1126 static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
1127 struct strbuf *buf)
1128 {
1129 Dwarf_Die *scopes;
1130 int count;
1131 size_t offset = 0;
1132 Dwarf_Addr base;
1133 Dwarf_Addr start, end;
1134 Dwarf_Addr entry;
1135 int ret;
1136 bool first = true;
1137 const char *name;
1138
1139 ret = die_entrypc(sp_die, &entry);
1140 if (ret)
1141 return ret;
1142
1143 name = dwarf_diename(sp_die);
1144 if (!name)
1145 return -ENOENT;
1146
1147 count = dwarf_getscopes_die(vr_die, &scopes);
1148
1149 /* (*SCOPES)[1] is the DIE for the scope containing that scope */
1150 if (count <= 1) {
1151 ret = -EINVAL;
1152 goto out;
1153 }
1154
1155 while ((offset = dwarf_ranges(&scopes[1], offset, &base,
1156 &start, &end)) > 0) {
1157 start -= entry;
1158 end -= entry;
1159
1160 if (first) {
1161 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1162 name, start, end);
1163 first = false;
1164 } else {
1165 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1166 start, end);
1167 }
1168 if (ret < 0)
1169 goto out;
1170 }
1171
1172 if (!first)
1173 ret = strbuf_add(buf, "]>", 2);
1174
1175 out:
1176 free(scopes);
1177 return ret;
1178 }
1179
1180 /**
1181 * die_get_var_range - Get byte offset range of given variable DIE
1182 * @sp_die: a subprogram DIE
1183 * @vr_die: a variable DIE
1184 * @buf: a strbuf for type and variable name and byte offset range
1185 *
1186 * Get the byte offset range of @vr_die and stores it in @buf as
1187 * "@<function_name+[NN-NN,NN-NN]>".
1188 */
die_get_var_range(Dwarf_Die * sp_die,Dwarf_Die * vr_die,struct strbuf * buf)1189 int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
1190 {
1191 int ret = 0;
1192 Dwarf_Addr base;
1193 Dwarf_Addr start, end;
1194 Dwarf_Addr entry;
1195 Dwarf_Op *op;
1196 size_t nops;
1197 size_t offset = 0;
1198 Dwarf_Attribute attr;
1199 bool first = true;
1200 const char *name;
1201
1202 ret = die_entrypc(sp_die, &entry);
1203 if (ret)
1204 return ret;
1205
1206 name = dwarf_diename(sp_die);
1207 if (!name)
1208 return -ENOENT;
1209
1210 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
1211 return -EINVAL;
1212
1213 while ((offset = dwarf_getlocations(&attr, offset, &base,
1214 &start, &end, &op, &nops)) > 0) {
1215 if (start == 0) {
1216 /* Single Location Descriptions */
1217 ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
1218 goto out;
1219 }
1220
1221 /* Location Lists */
1222 start -= entry;
1223 end -= entry;
1224 if (first) {
1225 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1226 name, start, end);
1227 first = false;
1228 } else {
1229 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1230 start, end);
1231 }
1232 if (ret < 0)
1233 goto out;
1234 }
1235
1236 if (!first)
1237 ret = strbuf_add(buf, "]>", 2);
1238 out:
1239 return ret;
1240 }
1241 #else
die_get_var_range(Dwarf_Die * sp_die __maybe_unused,Dwarf_Die * vr_die __maybe_unused,struct strbuf * buf __maybe_unused)1242 int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
1243 Dwarf_Die *vr_die __maybe_unused,
1244 struct strbuf *buf __maybe_unused)
1245 {
1246 return -ENOTSUP;
1247 }
1248 #endif
1249
1250 /*
1251 * die_has_loclist - Check if DW_AT_location of @vr_die is a location list
1252 * @vr_die: a variable DIE
1253 */
die_has_loclist(Dwarf_Die * vr_die)1254 static bool die_has_loclist(Dwarf_Die *vr_die)
1255 {
1256 Dwarf_Attribute loc;
1257 int tag = dwarf_tag(vr_die);
1258
1259 if (tag != DW_TAG_formal_parameter &&
1260 tag != DW_TAG_variable)
1261 return false;
1262
1263 return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
1264 dwarf_whatform(&loc) == DW_FORM_sec_offset);
1265 }
1266
1267 /*
1268 * die_is_optimized_target - Check if target program is compiled with
1269 * optimization
1270 * @cu_die: a CU DIE
1271 *
1272 * For any object in given CU whose DW_AT_location is a location list,
1273 * target program is compiled with optimization. This is applicable to
1274 * clang as well.
1275 */
die_is_optimized_target(Dwarf_Die * cu_die)1276 bool die_is_optimized_target(Dwarf_Die *cu_die)
1277 {
1278 Dwarf_Die tmp_die;
1279
1280 if (die_has_loclist(cu_die))
1281 return true;
1282
1283 if (!dwarf_child(cu_die, &tmp_die) &&
1284 die_is_optimized_target(&tmp_die))
1285 return true;
1286
1287 if (!dwarf_siblingof(cu_die, &tmp_die) &&
1288 die_is_optimized_target(&tmp_die))
1289 return true;
1290
1291 return false;
1292 }
1293
1294 /*
1295 * die_search_idx - Search index of given line address
1296 * @lines: Line records of single CU
1297 * @nr_lines: Number of @lines
1298 * @addr: address we are looking for
1299 * @idx: index to be set by this function (return value)
1300 *
1301 * Search for @addr by looping over every lines of CU. If address
1302 * matches, set index of that line in @idx. Note that single source
1303 * line can have multiple line records. i.e. single source line can
1304 * have multiple index.
1305 */
die_search_idx(Dwarf_Lines * lines,unsigned long nr_lines,Dwarf_Addr addr,unsigned long * idx)1306 static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
1307 Dwarf_Addr addr, unsigned long *idx)
1308 {
1309 unsigned long i;
1310 Dwarf_Addr tmp;
1311
1312 for (i = 0; i < nr_lines; i++) {
1313 if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
1314 return false;
1315
1316 if (tmp == addr) {
1317 *idx = i;
1318 return true;
1319 }
1320 }
1321 return false;
1322 }
1323
1324 /*
1325 * die_get_postprologue_addr - Search next address after function prologue
1326 * @entrypc_idx: entrypc index
1327 * @lines: Line records of single CU
1328 * @nr_lines: Number of @lines
1329 * @hignpc: high PC address of function
1330 * @postprologue_addr: Next address after function prologue (return value)
1331 *
1332 * Look for prologue-end marker. If there is no explicit marker, return
1333 * address of next line record or next source line.
1334 */
die_get_postprologue_addr(unsigned long entrypc_idx,Dwarf_Lines * lines,unsigned long nr_lines,Dwarf_Addr highpc,Dwarf_Addr * postprologue_addr)1335 static bool die_get_postprologue_addr(unsigned long entrypc_idx,
1336 Dwarf_Lines *lines,
1337 unsigned long nr_lines,
1338 Dwarf_Addr highpc,
1339 Dwarf_Addr *postprologue_addr)
1340 {
1341 unsigned long i;
1342 int entrypc_lno, lno;
1343 Dwarf_Line *line;
1344 Dwarf_Addr addr;
1345 bool p_end;
1346
1347 /* entrypc_lno is actual source line number */
1348 line = dwarf_onesrcline(lines, entrypc_idx);
1349 if (dwarf_lineno(line, &entrypc_lno))
1350 return false;
1351
1352 for (i = entrypc_idx; i < nr_lines; i++) {
1353 line = dwarf_onesrcline(lines, i);
1354
1355 if (dwarf_lineaddr(line, &addr) ||
1356 dwarf_lineno(line, &lno) ||
1357 dwarf_lineprologueend(line, &p_end))
1358 return false;
1359
1360 /* highpc is exclusive. [entrypc,highpc) */
1361 if (addr >= highpc)
1362 break;
1363
1364 /* clang supports prologue-end marker */
1365 if (p_end)
1366 break;
1367
1368 /* Actual next line in source */
1369 if (lno != entrypc_lno)
1370 break;
1371
1372 /*
1373 * Single source line can have multiple line records.
1374 * For Example,
1375 * void foo() { printf("hello\n"); }
1376 * contains two line records. One points to declaration and
1377 * other points to printf() line. Variable 'lno' won't get
1378 * incremented in this case but 'i' will.
1379 */
1380 if (i != entrypc_idx)
1381 break;
1382 }
1383
1384 dwarf_lineaddr(line, postprologue_addr);
1385 if (*postprologue_addr >= highpc)
1386 dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
1387 postprologue_addr);
1388
1389 return true;
1390 }
1391
1392 /*
1393 * die_skip_prologue - Use next address after prologue as probe location
1394 * @sp_die: a subprogram DIE
1395 * @cu_die: a CU DIE
1396 * @entrypc: entrypc of the function
1397 *
1398 * Function prologue prepares stack and registers before executing function
1399 * logic. When target program is compiled without optimization, function
1400 * parameter information is only valid after prologue. When we probe entrypc
1401 * of the function, and try to record function parameter, it contains
1402 * garbage value.
1403 */
die_skip_prologue(Dwarf_Die * sp_die,Dwarf_Die * cu_die,Dwarf_Addr * entrypc)1404 void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
1405 Dwarf_Addr *entrypc)
1406 {
1407 size_t nr_lines = 0;
1408 unsigned long entrypc_idx = 0;
1409 Dwarf_Lines *lines = NULL;
1410 Dwarf_Addr postprologue_addr;
1411 Dwarf_Addr highpc;
1412
1413 if (dwarf_highpc(sp_die, &highpc))
1414 return;
1415
1416 if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
1417 return;
1418
1419 if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
1420 return;
1421
1422 if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
1423 highpc, &postprologue_addr))
1424 return;
1425
1426 *entrypc = postprologue_addr;
1427 }
1428