xref: /linux/tools/perf/util/dwarf-aux.c (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e)
1 /*
2  * dwarf-aux.c : libdw auxiliary interfaces
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17  *
18  */
19 
20 #include <stdbool.h>
21 #include "util.h"
22 #include "debug.h"
23 #include "dwarf-aux.h"
24 
25 /**
26  * cu_find_realpath - Find the realpath of the target file
27  * @cu_die: A DIE(dwarf information entry) of CU(compilation Unit)
28  * @fname:  The tail filename of the target file
29  *
30  * Find the real(long) path of @fname in @cu_die.
31  */
32 const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
33 {
34 	Dwarf_Files *files;
35 	size_t nfiles, i;
36 	const char *src = NULL;
37 	int ret;
38 
39 	if (!fname)
40 		return NULL;
41 
42 	ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
43 	if (ret != 0)
44 		return NULL;
45 
46 	for (i = 0; i < nfiles; i++) {
47 		src = dwarf_filesrc(files, i, NULL, NULL);
48 		if (strtailcmp(src, fname) == 0)
49 			break;
50 	}
51 	if (i == nfiles)
52 		return NULL;
53 	return src;
54 }
55 
56 /**
57  * cu_get_comp_dir - Get the path of compilation directory
58  * @cu_die: a CU DIE
59  *
60  * Get the path of compilation directory of given @cu_die.
61  * Since this depends on DW_AT_comp_dir, older gcc will not
62  * embedded it. In that case, this returns NULL.
63  */
64 const char *cu_get_comp_dir(Dwarf_Die *cu_die)
65 {
66 	Dwarf_Attribute attr;
67 	if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
68 		return NULL;
69 	return dwarf_formstring(&attr);
70 }
71 
72 /**
73  * cu_find_lineinfo - Get a line number and file name for given address
74  * @cu_die: a CU DIE
75  * @addr: An address
76  * @fname: a pointer which returns the file name string
77  * @lineno: a pointer which returns the line number
78  *
79  * Find a line number and file name for @addr in @cu_die.
80  */
81 int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr,
82 		    const char **fname, int *lineno)
83 {
84 	Dwarf_Line *line;
85 	Dwarf_Addr laddr;
86 
87 	line = dwarf_getsrc_die(cu_die, (Dwarf_Addr)addr);
88 	if (line && dwarf_lineaddr(line, &laddr) == 0 &&
89 	    addr == (unsigned long)laddr && dwarf_lineno(line, lineno) == 0) {
90 		*fname = dwarf_linesrc(line, NULL, NULL);
91 		if (!*fname)
92 			/* line number is useless without filename */
93 			*lineno = 0;
94 	}
95 
96 	return *lineno ?: -ENOENT;
97 }
98 
99 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
100 
101 /**
102  * cu_walk_functions_at - Walk on function DIEs at given address
103  * @cu_die: A CU DIE
104  * @addr: An address
105  * @callback: A callback which called with found DIEs
106  * @data: A user data
107  *
108  * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
109  * should be subprogram or inlined-subroutines.
110  */
111 int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
112 		    int (*callback)(Dwarf_Die *, void *), void *data)
113 {
114 	Dwarf_Die die_mem;
115 	Dwarf_Die *sc_die;
116 	int ret = -ENOENT;
117 
118 	/* Inlined function could be recursive. Trace it until fail */
119 	for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
120 	     sc_die != NULL;
121 	     sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
122 				     &die_mem)) {
123 		ret = callback(sc_die, data);
124 		if (ret)
125 			break;
126 	}
127 
128 	return ret;
129 
130 }
131 
132 /**
133  * die_compare_name - Compare diename and tname
134  * @dw_die: a DIE
135  * @tname: a string of target name
136  *
137  * Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
138  */
139 bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
140 {
141 	const char *name;
142 	name = dwarf_diename(dw_die);
143 	return name ? (strcmp(tname, name) == 0) : false;
144 }
145 
146 /**
147  * die_get_call_lineno - Get callsite line number of inline-function instance
148  * @in_die: a DIE of an inlined function instance
149  *
150  * Get call-site line number of @in_die. This means from where the inline
151  * function is called.
152  */
153 int die_get_call_lineno(Dwarf_Die *in_die)
154 {
155 	Dwarf_Attribute attr;
156 	Dwarf_Word ret;
157 
158 	if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
159 		return -ENOENT;
160 
161 	dwarf_formudata(&attr, &ret);
162 	return (int)ret;
163 }
164 
165 /**
166  * die_get_type - Get type DIE
167  * @vr_die: a DIE of a variable
168  * @die_mem: where to store a type DIE
169  *
170  * Get a DIE of the type of given variable (@vr_die), and store
171  * it to die_mem. Return NULL if fails to get a type DIE.
172  */
173 Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
174 {
175 	Dwarf_Attribute attr;
176 
177 	if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
178 	    dwarf_formref_die(&attr, die_mem))
179 		return die_mem;
180 	else
181 		return NULL;
182 }
183 
184 /* Get a type die, but skip qualifiers */
185 static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
186 {
187 	int tag;
188 
189 	do {
190 		vr_die = die_get_type(vr_die, die_mem);
191 		if (!vr_die)
192 			break;
193 		tag = dwarf_tag(vr_die);
194 	} while (tag == DW_TAG_const_type ||
195 		 tag == DW_TAG_restrict_type ||
196 		 tag == DW_TAG_volatile_type ||
197 		 tag == DW_TAG_shared_type);
198 
199 	return vr_die;
200 }
201 
202 /**
203  * die_get_real_type - Get a type die, but skip qualifiers and typedef
204  * @vr_die: a DIE of a variable
205  * @die_mem: where to store a type DIE
206  *
207  * Get a DIE of the type of given variable (@vr_die), and store
208  * it to die_mem. Return NULL if fails to get a type DIE.
209  * If the type is qualifiers (e.g. const) or typedef, this skips it
210  * and tries to find real type (structure or basic types, e.g. int).
211  */
212 Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
213 {
214 	do {
215 		vr_die = __die_get_real_type(vr_die, die_mem);
216 	} while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
217 
218 	return vr_die;
219 }
220 
221 /* Get attribute and translate it as a udata */
222 static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
223 			      Dwarf_Word *result)
224 {
225 	Dwarf_Attribute attr;
226 
227 	if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
228 	    dwarf_formudata(&attr, result) != 0)
229 		return -ENOENT;
230 
231 	return 0;
232 }
233 
234 /* Get attribute and translate it as a sdata */
235 static int die_get_attr_sdata(Dwarf_Die *tp_die, unsigned int attr_name,
236 			      Dwarf_Sword *result)
237 {
238 	Dwarf_Attribute attr;
239 
240 	if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
241 	    dwarf_formsdata(&attr, result) != 0)
242 		return -ENOENT;
243 
244 	return 0;
245 }
246 
247 /**
248  * die_is_signed_type - Check whether a type DIE is signed or not
249  * @tp_die: a DIE of a type
250  *
251  * Get the encoding of @tp_die and return true if the encoding
252  * is signed.
253  */
254 bool die_is_signed_type(Dwarf_Die *tp_die)
255 {
256 	Dwarf_Word ret;
257 
258 	if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
259 		return false;
260 
261 	return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
262 		ret == DW_ATE_signed_fixed);
263 }
264 
265 /**
266  * die_get_data_member_location - Get the data-member offset
267  * @mb_die: a DIE of a member of a data structure
268  * @offs: The offset of the member in the data structure
269  *
270  * Get the offset of @mb_die in the data structure including @mb_die, and
271  * stores result offset to @offs. If any error occurs this returns errno.
272  */
273 int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
274 {
275 	Dwarf_Attribute attr;
276 	Dwarf_Op *expr;
277 	size_t nexpr;
278 	int ret;
279 
280 	if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
281 		return -ENOENT;
282 
283 	if (dwarf_formudata(&attr, offs) != 0) {
284 		/* DW_AT_data_member_location should be DW_OP_plus_uconst */
285 		ret = dwarf_getlocation(&attr, &expr, &nexpr);
286 		if (ret < 0 || nexpr == 0)
287 			return -ENOENT;
288 
289 		if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
290 			pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
291 				 expr[0].atom, nexpr);
292 			return -ENOTSUP;
293 		}
294 		*offs = (Dwarf_Word)expr[0].number;
295 	}
296 	return 0;
297 }
298 
299 /* Get the call file index number in CU DIE */
300 static int die_get_call_fileno(Dwarf_Die *in_die)
301 {
302 	Dwarf_Sword idx;
303 
304 	if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0)
305 		return (int)idx;
306 	else
307 		return -ENOENT;
308 }
309 
310 /* Get the declared file index number in CU DIE */
311 static int die_get_decl_fileno(Dwarf_Die *pdie)
312 {
313 	Dwarf_Sword idx;
314 
315 	if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0)
316 		return (int)idx;
317 	else
318 		return -ENOENT;
319 }
320 
321 /**
322  * die_get_call_file - Get callsite file name of inlined function instance
323  * @in_die: a DIE of an inlined function instance
324  *
325  * Get call-site file name of @in_die. This means from which file the inline
326  * function is called.
327  */
328 const char *die_get_call_file(Dwarf_Die *in_die)
329 {
330 	Dwarf_Die cu_die;
331 	Dwarf_Files *files;
332 	int idx;
333 
334 	idx = die_get_call_fileno(in_die);
335 	if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
336 	    dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
337 		return NULL;
338 
339 	return dwarf_filesrc(files, idx, NULL, NULL);
340 }
341 
342 
343 /**
344  * die_find_child - Generic DIE search function in DIE tree
345  * @rt_die: a root DIE
346  * @callback: a callback function
347  * @data: a user data passed to the callback function
348  * @die_mem: a buffer for result DIE
349  *
350  * Trace DIE tree from @rt_die and call @callback for each child DIE.
351  * If @callback returns DIE_FIND_CB_END, this stores the DIE into
352  * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
353  * this continues to trace the tree. Optionally, @callback can return
354  * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
355  * the children and trace only the siblings respectively.
356  * Returns NULL if @callback can't find any appropriate DIE.
357  */
358 Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
359 			  int (*callback)(Dwarf_Die *, void *),
360 			  void *data, Dwarf_Die *die_mem)
361 {
362 	Dwarf_Die child_die;
363 	int ret;
364 
365 	ret = dwarf_child(rt_die, die_mem);
366 	if (ret != 0)
367 		return NULL;
368 
369 	do {
370 		ret = callback(die_mem, data);
371 		if (ret == DIE_FIND_CB_END)
372 			return die_mem;
373 
374 		if ((ret & DIE_FIND_CB_CHILD) &&
375 		    die_find_child(die_mem, callback, data, &child_die)) {
376 			memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
377 			return die_mem;
378 		}
379 	} while ((ret & DIE_FIND_CB_SIBLING) &&
380 		 dwarf_siblingof(die_mem, die_mem) == 0);
381 
382 	return NULL;
383 }
384 
385 struct __addr_die_search_param {
386 	Dwarf_Addr	addr;
387 	Dwarf_Die	*die_mem;
388 };
389 
390 /* die_find callback for non-inlined function search */
391 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
392 {
393 	struct __addr_die_search_param *ad = data;
394 
395 	if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
396 	    dwarf_haspc(fn_die, ad->addr)) {
397 		memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
398 		return DWARF_CB_ABORT;
399 	}
400 	return DWARF_CB_OK;
401 }
402 
403 /**
404  * die_find_realfunc - Search a non-inlined function at given address
405  * @cu_die: a CU DIE which including @addr
406  * @addr: target address
407  * @die_mem: a buffer for result DIE
408  *
409  * Search a non-inlined function DIE which includes @addr. Stores the
410  * DIE to @die_mem and returns it if found. Returns NULl if failed.
411  */
412 Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
413 				    Dwarf_Die *die_mem)
414 {
415 	struct __addr_die_search_param ad;
416 	ad.addr = addr;
417 	ad.die_mem = die_mem;
418 	/* dwarf_getscopes can't find subprogram. */
419 	if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
420 		return NULL;
421 	else
422 		return die_mem;
423 }
424 
425 /* die_find callback for inline function search */
426 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
427 {
428 	Dwarf_Addr *addr = data;
429 
430 	if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
431 	    dwarf_haspc(die_mem, *addr))
432 		return DIE_FIND_CB_END;
433 
434 	return DIE_FIND_CB_CONTINUE;
435 }
436 
437 /**
438  * die_find_inlinefunc - Search an inlined function at given address
439  * @cu_die: a CU DIE which including @addr
440  * @addr: target address
441  * @die_mem: a buffer for result DIE
442  *
443  * Search an inlined function DIE which includes @addr. Stores the
444  * DIE to @die_mem and returns it if found. Returns NULl if failed.
445  * If several inlined functions are expanded recursively, this trace
446  * it and returns deepest one.
447  */
448 Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
449 			       Dwarf_Die *die_mem)
450 {
451 	Dwarf_Die tmp_die;
452 
453 	sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
454 	if (!sp_die)
455 		return NULL;
456 
457 	/* Inlined function could be recursive. Trace it until fail */
458 	while (sp_die) {
459 		memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
460 		sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
461 					&tmp_die);
462 	}
463 
464 	return die_mem;
465 }
466 
467 struct __instance_walk_param {
468 	void    *addr;
469 	int	(*callback)(Dwarf_Die *, void *);
470 	void    *data;
471 	int	retval;
472 };
473 
474 static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
475 {
476 	struct __instance_walk_param *iwp = data;
477 	Dwarf_Attribute attr_mem;
478 	Dwarf_Die origin_mem;
479 	Dwarf_Attribute *attr;
480 	Dwarf_Die *origin;
481 	int tmp;
482 
483 	attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
484 	if (attr == NULL)
485 		return DIE_FIND_CB_CONTINUE;
486 
487 	origin = dwarf_formref_die(attr, &origin_mem);
488 	if (origin == NULL || origin->addr != iwp->addr)
489 		return DIE_FIND_CB_CONTINUE;
490 
491 	/* Ignore redundant instances */
492 	if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
493 		dwarf_decl_line(origin, &tmp);
494 		if (die_get_call_lineno(inst) == tmp) {
495 			tmp = die_get_decl_fileno(origin);
496 			if (die_get_call_fileno(inst) == tmp)
497 				return DIE_FIND_CB_CONTINUE;
498 		}
499 	}
500 
501 	iwp->retval = iwp->callback(inst, iwp->data);
502 
503 	return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
504 }
505 
506 /**
507  * die_walk_instances - Walk on instances of given DIE
508  * @or_die: an abstract original DIE
509  * @callback: a callback function which is called with instance DIE
510  * @data: user data
511  *
512  * Walk on the instances of give @in_die. @in_die must be an inlined function
513  * declartion. This returns the return value of @callback if it returns
514  * non-zero value, or -ENOENT if there is no instance.
515  */
516 int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
517 		       void *data)
518 {
519 	Dwarf_Die cu_die;
520 	Dwarf_Die die_mem;
521 	struct __instance_walk_param iwp = {
522 		.addr = or_die->addr,
523 		.callback = callback,
524 		.data = data,
525 		.retval = -ENOENT,
526 	};
527 
528 	if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
529 		return -ENOENT;
530 
531 	die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
532 
533 	return iwp.retval;
534 }
535 
536 /* Line walker internal parameters */
537 struct __line_walk_param {
538 	bool recursive;
539 	line_walk_callback_t callback;
540 	void *data;
541 	int retval;
542 };
543 
544 static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
545 {
546 	struct __line_walk_param *lw = data;
547 	Dwarf_Addr addr = 0;
548 	const char *fname;
549 	int lineno;
550 
551 	if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
552 		fname = die_get_call_file(in_die);
553 		lineno = die_get_call_lineno(in_die);
554 		if (fname && lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
555 			lw->retval = lw->callback(fname, lineno, addr, lw->data);
556 			if (lw->retval != 0)
557 				return DIE_FIND_CB_END;
558 		}
559 	}
560 	if (!lw->recursive)
561 		/* Don't need to search recursively */
562 		return DIE_FIND_CB_SIBLING;
563 
564 	if (addr) {
565 		fname = dwarf_decl_file(in_die);
566 		if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
567 			lw->retval = lw->callback(fname, lineno, addr, lw->data);
568 			if (lw->retval != 0)
569 				return DIE_FIND_CB_END;
570 		}
571 	}
572 
573 	/* Continue to search nested inlined function call-sites */
574 	return DIE_FIND_CB_CONTINUE;
575 }
576 
577 /* Walk on lines of blocks included in given DIE */
578 static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
579 				line_walk_callback_t callback, void *data)
580 {
581 	struct __line_walk_param lw = {
582 		.recursive = recursive,
583 		.callback = callback,
584 		.data = data,
585 		.retval = 0,
586 	};
587 	Dwarf_Die die_mem;
588 	Dwarf_Addr addr;
589 	const char *fname;
590 	int lineno;
591 
592 	/* Handle function declaration line */
593 	fname = dwarf_decl_file(sp_die);
594 	if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
595 	    dwarf_entrypc(sp_die, &addr) == 0) {
596 		lw.retval = callback(fname, lineno, addr, data);
597 		if (lw.retval != 0)
598 			goto done;
599 	}
600 	die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
601 done:
602 	return lw.retval;
603 }
604 
605 static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
606 {
607 	struct __line_walk_param *lw = data;
608 
609 	lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
610 	if (lw->retval != 0)
611 		return DWARF_CB_ABORT;
612 
613 	return DWARF_CB_OK;
614 }
615 
616 /**
617  * die_walk_lines - Walk on lines inside given DIE
618  * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
619  * @callback: callback routine
620  * @data: user data
621  *
622  * Walk on all lines inside given @rt_die and call @callback on each line.
623  * If the @rt_die is a function, walk only on the lines inside the function,
624  * otherwise @rt_die must be a CU DIE.
625  * Note that this walks not only dwarf line list, but also function entries
626  * and inline call-site.
627  */
628 int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
629 {
630 	Dwarf_Lines *lines;
631 	Dwarf_Line *line;
632 	Dwarf_Addr addr;
633 	const char *fname;
634 	int lineno, ret = 0;
635 	Dwarf_Die die_mem, *cu_die;
636 	size_t nlines, i;
637 
638 	/* Get the CU die */
639 	if (dwarf_tag(rt_die) != DW_TAG_compile_unit)
640 		cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
641 	else
642 		cu_die = rt_die;
643 	if (!cu_die) {
644 		pr_debug2("Failed to get CU from given DIE.\n");
645 		return -EINVAL;
646 	}
647 
648 	/* Get lines list in the CU */
649 	if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
650 		pr_debug2("Failed to get source lines on this CU.\n");
651 		return -ENOENT;
652 	}
653 	pr_debug2("Get %zd lines from this CU\n", nlines);
654 
655 	/* Walk on the lines on lines list */
656 	for (i = 0; i < nlines; i++) {
657 		line = dwarf_onesrcline(lines, i);
658 		if (line == NULL ||
659 		    dwarf_lineno(line, &lineno) != 0 ||
660 		    dwarf_lineaddr(line, &addr) != 0) {
661 			pr_debug2("Failed to get line info. "
662 				  "Possible error in debuginfo.\n");
663 			continue;
664 		}
665 		/* Filter lines based on address */
666 		if (rt_die != cu_die)
667 			/*
668 			 * Address filtering
669 			 * The line is included in given function, and
670 			 * no inline block includes it.
671 			 */
672 			if (!dwarf_haspc(rt_die, addr) ||
673 			    die_find_inlinefunc(rt_die, addr, &die_mem))
674 				continue;
675 		/* Get source line */
676 		fname = dwarf_linesrc(line, NULL, NULL);
677 
678 		ret = callback(fname, lineno, addr, data);
679 		if (ret != 0)
680 			return ret;
681 	}
682 
683 	/*
684 	 * Dwarf lines doesn't include function declarations and inlined
685 	 * subroutines. We have to check functions list or given function.
686 	 */
687 	if (rt_die != cu_die)
688 		/*
689 		 * Don't need walk functions recursively, because nested
690 		 * inlined functions don't have lines of the specified DIE.
691 		 */
692 		ret = __die_walk_funclines(rt_die, false, callback, data);
693 	else {
694 		struct __line_walk_param param = {
695 			.callback = callback,
696 			.data = data,
697 			.retval = 0,
698 		};
699 		dwarf_getfuncs(cu_die, __die_walk_culines_cb, &param, 0);
700 		ret = param.retval;
701 	}
702 
703 	return ret;
704 }
705 
706 struct __find_variable_param {
707 	const char *name;
708 	Dwarf_Addr addr;
709 };
710 
711 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
712 {
713 	struct __find_variable_param *fvp = data;
714 	int tag;
715 
716 	tag = dwarf_tag(die_mem);
717 	if ((tag == DW_TAG_formal_parameter ||
718 	     tag == DW_TAG_variable) &&
719 	    die_compare_name(die_mem, fvp->name))
720 		return DIE_FIND_CB_END;
721 
722 	if (dwarf_haspc(die_mem, fvp->addr))
723 		return DIE_FIND_CB_CONTINUE;
724 	else
725 		return DIE_FIND_CB_SIBLING;
726 }
727 
728 /**
729  * die_find_variable_at - Find a given name variable at given address
730  * @sp_die: a function DIE
731  * @name: variable name
732  * @addr: address
733  * @die_mem: a buffer for result DIE
734  *
735  * Find a variable DIE called @name at @addr in @sp_die.
736  */
737 Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
738 				Dwarf_Addr addr, Dwarf_Die *die_mem)
739 {
740 	struct __find_variable_param fvp = { .name = name, .addr = addr};
741 
742 	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
743 			      die_mem);
744 }
745 
746 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
747 {
748 	const char *name = data;
749 
750 	if ((dwarf_tag(die_mem) == DW_TAG_member) &&
751 	    die_compare_name(die_mem, name))
752 		return DIE_FIND_CB_END;
753 
754 	return DIE_FIND_CB_SIBLING;
755 }
756 
757 /**
758  * die_find_member - Find a given name member in a data structure
759  * @st_die: a data structure type DIE
760  * @name: member name
761  * @die_mem: a buffer for result DIE
762  *
763  * Find a member DIE called @name in @st_die.
764  */
765 Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
766 			   Dwarf_Die *die_mem)
767 {
768 	return die_find_child(st_die, __die_find_member_cb, (void *)name,
769 			      die_mem);
770 }
771 
772 /**
773  * die_get_typename - Get the name of given variable DIE
774  * @vr_die: a variable DIE
775  * @buf: a buffer for result type name
776  * @len: a max-length of @buf
777  *
778  * Get the name of @vr_die and stores it to @buf. Return the actual length
779  * of type name if succeeded. Return -E2BIG if @len is not enough long, and
780  * Return -ENOENT if failed to find type name.
781  * Note that the result will stores typedef name if possible, and stores
782  * "*(function_type)" if the type is a function pointer.
783  */
784 int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
785 {
786 	Dwarf_Die type;
787 	int tag, ret, ret2;
788 	const char *tmp = "";
789 
790 	if (__die_get_real_type(vr_die, &type) == NULL)
791 		return -ENOENT;
792 
793 	tag = dwarf_tag(&type);
794 	if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
795 		tmp = "*";
796 	else if (tag == DW_TAG_subroutine_type) {
797 		/* Function pointer */
798 		ret = snprintf(buf, len, "(function_type)");
799 		return (ret >= len) ? -E2BIG : ret;
800 	} else {
801 		if (!dwarf_diename(&type))
802 			return -ENOENT;
803 		if (tag == DW_TAG_union_type)
804 			tmp = "union ";
805 		else if (tag == DW_TAG_structure_type)
806 			tmp = "struct ";
807 		else if (tag == DW_TAG_enumeration_type)
808 			tmp = "enum ";
809 		/* Write a base name */
810 		ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
811 		return (ret >= len) ? -E2BIG : ret;
812 	}
813 	ret = die_get_typename(&type, buf, len);
814 	if (ret > 0) {
815 		ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
816 		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
817 	}
818 	return ret;
819 }
820 
821 /**
822  * die_get_varname - Get the name and type of given variable DIE
823  * @vr_die: a variable DIE
824  * @buf: a buffer for type and variable name
825  * @len: the max-length of @buf
826  *
827  * Get the name and type of @vr_die and stores it in @buf as "type\tname".
828  */
829 int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
830 {
831 	int ret, ret2;
832 
833 	ret = die_get_typename(vr_die, buf, len);
834 	if (ret < 0) {
835 		pr_debug("Failed to get type, make it unknown.\n");
836 		ret = snprintf(buf, len, "(unknown_type)");
837 	}
838 	if (ret > 0) {
839 		ret2 = snprintf(buf + ret, len - ret, "\t%s",
840 				dwarf_diename(vr_die));
841 		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
842 	}
843 	return ret;
844 }
845 
846