1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * dwarf-aux.c : libdw auxiliary interfaces
11 #include "dwarf-aux.h"
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
20 * Find the real(long) path of @fname in @cu_die.
22 const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
26 const char *src = NULL;
32 ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
36 for (i = 0; i < nfiles; i++) {
37 src = dwarf_filesrc(files, i, NULL, NULL);
38 if (strtailcmp(src, fname) == 0)
47 * cu_get_comp_dir - Get the path of compilation directory
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.
54 const char *cu_get_comp_dir(Dwarf_Die *cu_die)
57 if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
59 return dwarf_formstring(&attr);
62 /* Unlike dwarf_getsrc_die(), cu_getsrc_die() only returns statement line */
63 static Dwarf_Line *cu_getsrc_die(Dwarf_Die *cu_die, Dwarf_Addr addr)
68 size_t nlines, l, u, n;
71 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0 ||
75 /* Lines are sorted by address, use binary search */
76 l = 0; u = nlines - 1;
79 line = dwarf_onesrcline(lines, n);
80 if (!line || dwarf_lineaddr(line, &laddr) != 0)
87 /* Going backward to find the lowest line */
89 line = dwarf_onesrcline(lines, --l);
90 if (!line || dwarf_lineaddr(line, &laddr) != 0)
92 } while (laddr == addr);
94 /* Going foward to find the statement line */
96 line = dwarf_onesrcline(lines, l++);
97 if (!line || dwarf_lineaddr(line, &laddr) != 0 ||
98 dwarf_linebeginstatement(line, &flag) != 0)
108 * cu_find_lineinfo - Get a line number and file name for given address
111 * @fname: a pointer which returns the file name string
112 * @lineno: a pointer which returns the line number
114 * Find a line number and file name for @addr in @cu_die.
116 int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr,
117 const char **fname, int *lineno)
123 if (die_find_realfunc(cu_die, (Dwarf_Addr)addr, &die_mem)
124 && die_entrypc(&die_mem, &faddr) == 0 &&
126 *fname = dwarf_decl_file(&die_mem);
127 dwarf_decl_line(&die_mem, lineno);
131 line = cu_getsrc_die(cu_die, (Dwarf_Addr)addr);
132 if (line && dwarf_lineno(line, lineno) == 0) {
133 *fname = dwarf_linesrc(line, NULL, NULL);
135 /* line number is useless without filename */
140 return *lineno ?: -ENOENT;
143 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
146 * cu_walk_functions_at - Walk on function DIEs at given address
149 * @callback: A callback which called with found DIEs
152 * Walk on function DIEs at given @addr in @cu_die. Passed DIEs
153 * should be subprogram or inlined-subroutines.
155 int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
156 int (*callback)(Dwarf_Die *, void *), void *data)
162 /* Inlined function could be recursive. Trace it until fail */
163 for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
165 sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
167 ret = callback(sc_die, data);
177 * die_get_linkage_name - Get the linkage name of the object
178 * @dw_die: A DIE of the object
180 * Get the linkage name attiribute of given @dw_die.
181 * For C++ binary, the linkage name will be the mangled symbol.
183 const char *die_get_linkage_name(Dwarf_Die *dw_die)
185 Dwarf_Attribute attr;
187 if (dwarf_attr_integrate(dw_die, DW_AT_linkage_name, &attr) == NULL)
189 return dwarf_formstring(&attr);
193 * die_compare_name - Compare diename and tname
195 * @tname: a string of target name
197 * Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
199 bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
203 name = dwarf_diename(dw_die);
204 return name ? (strcmp(tname, name) == 0) : false;
208 * die_match_name - Match diename/linkage name and glob
210 * @glob: a string of target glob pattern
212 * Glob matching the name of @dw_die and @glob. Return false if matching fail.
213 * This also match linkage name.
215 bool die_match_name(Dwarf_Die *dw_die, const char *glob)
219 name = dwarf_diename(dw_die);
220 if (name && strglobmatch(name, glob))
222 /* fall back to check linkage name */
223 name = die_get_linkage_name(dw_die);
224 if (name && strglobmatch(name, glob))
231 * die_get_call_lineno - Get callsite line number of inline-function instance
232 * @in_die: a DIE of an inlined function instance
234 * Get call-site line number of @in_die. This means from where the inline
235 * function is called.
237 int die_get_call_lineno(Dwarf_Die *in_die)
239 Dwarf_Attribute attr;
242 if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
245 dwarf_formudata(&attr, &ret);
250 * die_get_type - Get type DIE
251 * @vr_die: a DIE of a variable
252 * @die_mem: where to store a type DIE
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.
257 Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
259 Dwarf_Attribute attr;
261 if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
262 dwarf_formref_die(&attr, die_mem))
268 /* Get a type die, but skip qualifiers */
269 static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
274 vr_die = die_get_type(vr_die, die_mem);
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);
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
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).
296 Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
299 vr_die = __die_get_real_type(vr_die, die_mem);
300 } while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
305 /* Get attribute and translate it as a udata */
306 static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
309 Dwarf_Attribute attr;
311 if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
312 dwarf_formudata(&attr, result) != 0)
318 /* Get attribute and translate it as a sdata */
319 static int die_get_attr_sdata(Dwarf_Die *tp_die, unsigned int attr_name,
322 Dwarf_Attribute attr;
324 if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
325 dwarf_formsdata(&attr, result) != 0)
332 * die_is_signed_type - Check whether a type DIE is signed or not
333 * @tp_die: a DIE of a type
335 * Get the encoding of @tp_die and return true if the encoding
338 bool die_is_signed_type(Dwarf_Die *tp_die)
342 if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
345 return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
346 ret == DW_ATE_signed_fixed);
350 * die_is_func_def - Ensure that this DIE is a subprogram and definition
353 * Ensure that this DIE is a subprogram and NOT a declaration. This
354 * returns true if @dw_die is a function definition.
356 bool die_is_func_def(Dwarf_Die *dw_die)
358 Dwarf_Attribute attr;
360 return (dwarf_tag(dw_die) == DW_TAG_subprogram &&
361 dwarf_attr(dw_die, DW_AT_declaration, &attr) == NULL);
365 * die_entrypc - Returns entry PC (the lowest address) of a DIE
367 * @addr: where to store entry PC
369 * Since dwarf_entrypc() does not return entry PC if the DIE has only address
370 * range, we have to use this to retrieve the lowest address from the address
373 int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)
375 Dwarf_Addr base, end;
376 Dwarf_Attribute attr;
381 if (dwarf_entrypc(dw_die, addr) == 0)
385 * Since the dwarf_ranges() will return 0 if there is no
386 * DW_AT_ranges attribute, we should check it first.
388 if (!dwarf_attr(dw_die, DW_AT_ranges, &attr))
391 return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;
395 * die_is_func_instance - Ensure that this DIE is an instance of a subprogram
398 * Ensure that this DIE is an instance (which has an entry address).
399 * This returns true if @dw_die is a function instance. If not, the @dw_die
400 * must be a prototype. You can use die_walk_instances() to find actual
403 bool die_is_func_instance(Dwarf_Die *dw_die)
406 Dwarf_Attribute attr_mem;
407 int tag = dwarf_tag(dw_die);
409 if (tag != DW_TAG_subprogram &&
410 tag != DW_TAG_inlined_subroutine)
413 return dwarf_entrypc(dw_die, &tmp) == 0 ||
414 dwarf_attr(dw_die, DW_AT_ranges, &attr_mem) != NULL;
418 * die_get_data_member_location - Get the data-member offset
419 * @mb_die: a DIE of a member of a data structure
420 * @offs: The offset of the member in the data structure
422 * Get the offset of @mb_die in the data structure including @mb_die, and
423 * stores result offset to @offs. If any error occurs this returns errno.
425 int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
427 Dwarf_Attribute attr;
432 if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
435 if (dwarf_formudata(&attr, offs) != 0) {
436 /* DW_AT_data_member_location should be DW_OP_plus_uconst */
437 ret = dwarf_getlocation(&attr, &expr, &nexpr);
438 if (ret < 0 || nexpr == 0)
441 if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
442 pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
443 expr[0].atom, nexpr);
446 *offs = (Dwarf_Word)expr[0].number;
451 /* Get the call file index number in CU DIE */
452 static int die_get_call_fileno(Dwarf_Die *in_die)
456 if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0)
462 /* Get the declared file index number in CU DIE */
463 static int die_get_decl_fileno(Dwarf_Die *pdie)
467 if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0)
474 * die_get_call_file - Get callsite file name of inlined function instance
475 * @in_die: a DIE of an inlined function instance
477 * Get call-site file name of @in_die. This means from which file the inline
478 * function is called.
480 const char *die_get_call_file(Dwarf_Die *in_die)
486 idx = die_get_call_fileno(in_die);
487 if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
488 dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
491 return dwarf_filesrc(files, idx, NULL, NULL);
496 * die_find_child - Generic DIE search function in DIE tree
497 * @rt_die: a root DIE
498 * @callback: a callback function
499 * @data: a user data passed to the callback function
500 * @die_mem: a buffer for result DIE
502 * Trace DIE tree from @rt_die and call @callback for each child DIE.
503 * If @callback returns DIE_FIND_CB_END, this stores the DIE into
504 * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
505 * this continues to trace the tree. Optionally, @callback can return
506 * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
507 * the children and trace only the siblings respectively.
508 * Returns NULL if @callback can't find any appropriate DIE.
510 Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
511 int (*callback)(Dwarf_Die *, void *),
512 void *data, Dwarf_Die *die_mem)
517 ret = dwarf_child(rt_die, die_mem);
522 ret = callback(die_mem, data);
523 if (ret == DIE_FIND_CB_END)
526 if ((ret & DIE_FIND_CB_CHILD) &&
527 die_find_child(die_mem, callback, data, &child_die)) {
528 memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
531 } while ((ret & DIE_FIND_CB_SIBLING) &&
532 dwarf_siblingof(die_mem, die_mem) == 0);
537 struct __addr_die_search_param {
542 static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
544 struct __addr_die_search_param *ad = data;
547 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
548 !dwarf_highpc(fn_die, &addr) &&
550 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
551 return DWARF_CB_ABORT;
557 * die_find_tailfunc - Search for a non-inlined function with tail call at
559 * @cu_die: a CU DIE which including @addr
560 * @addr: target address
561 * @die_mem: a buffer for result DIE
563 * Search for a non-inlined function DIE with tail call at @addr. Stores the
564 * DIE to @die_mem and returns it if found. Returns NULL if failed.
566 Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
569 struct __addr_die_search_param ad;
571 ad.die_mem = die_mem;
572 /* dwarf_getscopes can't find subprogram. */
573 if (!dwarf_getfuncs(cu_die, __die_search_func_tail_cb, &ad, 0))
579 /* die_find callback for non-inlined function search */
580 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
582 struct __addr_die_search_param *ad = data;
585 * Since a declaration entry doesn't has given pc, this always returns
586 * function definition entry.
588 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
589 dwarf_haspc(fn_die, ad->addr)) {
590 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
591 return DWARF_CB_ABORT;
597 * die_find_realfunc - Search a non-inlined function at given address
598 * @cu_die: a CU DIE which including @addr
599 * @addr: target address
600 * @die_mem: a buffer for result DIE
602 * Search a non-inlined function DIE which includes @addr. Stores the
603 * DIE to @die_mem and returns it if found. Returns NULL if failed.
605 Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
608 struct __addr_die_search_param ad;
610 ad.die_mem = die_mem;
611 /* dwarf_getscopes can't find subprogram. */
612 if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
618 /* die_find callback for inline function search */
619 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
621 Dwarf_Addr *addr = data;
623 if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
624 dwarf_haspc(die_mem, *addr))
625 return DIE_FIND_CB_END;
627 return DIE_FIND_CB_CONTINUE;
631 * die_find_top_inlinefunc - Search the top inlined function at given address
632 * @sp_die: a subprogram DIE which including @addr
633 * @addr: target address
634 * @die_mem: a buffer for result DIE
636 * Search an inlined function DIE which includes @addr. Stores the
637 * DIE to @die_mem and returns it if found. Returns NULL if failed.
638 * Even if several inlined functions are expanded recursively, this
639 * doesn't trace it down, and returns the topmost one.
641 Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
644 return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
648 * die_find_inlinefunc - Search an inlined function at given address
649 * @sp_die: a subprogram DIE which including @addr
650 * @addr: target address
651 * @die_mem: a buffer for result DIE
653 * Search an inlined function DIE which includes @addr. Stores the
654 * DIE to @die_mem and returns it if found. Returns NULL if failed.
655 * If several inlined functions are expanded recursively, this trace
656 * it down and returns deepest one.
658 Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
663 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
667 /* Inlined function could be recursive. Trace it until fail */
669 memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
670 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
677 struct __instance_walk_param {
679 int (*callback)(Dwarf_Die *, void *);
684 static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
686 struct __instance_walk_param *iwp = data;
687 Dwarf_Attribute attr_mem;
688 Dwarf_Die origin_mem;
689 Dwarf_Attribute *attr;
693 if (!die_is_func_instance(inst))
694 return DIE_FIND_CB_CONTINUE;
696 attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
698 return DIE_FIND_CB_CONTINUE;
700 origin = dwarf_formref_die(attr, &origin_mem);
701 if (origin == NULL || origin->addr != iwp->addr)
702 return DIE_FIND_CB_CONTINUE;
704 /* Ignore redundant instances */
705 if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
706 dwarf_decl_line(origin, &tmp);
707 if (die_get_call_lineno(inst) == tmp) {
708 tmp = die_get_decl_fileno(origin);
709 if (die_get_call_fileno(inst) == tmp)
710 return DIE_FIND_CB_CONTINUE;
714 iwp->retval = iwp->callback(inst, iwp->data);
716 return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
720 * die_walk_instances - Walk on instances of given DIE
721 * @or_die: an abstract original DIE
722 * @callback: a callback function which is called with instance DIE
725 * Walk on the instances of give @in_die. @in_die must be an inlined function
726 * declartion. This returns the return value of @callback if it returns
727 * non-zero value, or -ENOENT if there is no instance.
729 int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
734 struct __instance_walk_param iwp = {
735 .addr = or_die->addr,
736 .callback = callback,
741 if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
744 die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
749 /* Line walker internal parameters */
750 struct __line_walk_param {
752 line_walk_callback_t callback;
757 static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
759 struct __line_walk_param *lw = data;
764 if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
765 fname = die_get_call_file(in_die);
766 lineno = die_get_call_lineno(in_die);
767 if (fname && lineno > 0 && die_entrypc(in_die, &addr) == 0) {
768 lw->retval = lw->callback(fname, lineno, addr, lw->data);
770 return DIE_FIND_CB_END;
773 return DIE_FIND_CB_SIBLING;
777 fname = dwarf_decl_file(in_die);
778 if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
779 lw->retval = lw->callback(fname, lineno, addr, lw->data);
781 return DIE_FIND_CB_END;
785 /* Continue to search nested inlined function call-sites */
786 return DIE_FIND_CB_CONTINUE;
789 /* Walk on lines of blocks included in given DIE */
790 static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
791 line_walk_callback_t callback, void *data)
793 struct __line_walk_param lw = {
794 .recursive = recursive,
795 .callback = callback,
804 /* Handle function declaration line */
805 fname = dwarf_decl_file(sp_die);
806 if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
807 die_entrypc(sp_die, &addr) == 0) {
808 lw.retval = callback(fname, lineno, addr, data);
812 die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
817 static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
819 struct __line_walk_param *lw = data;
822 * Since inlined function can include another inlined function in
823 * the same file, we need to walk in it recursively.
825 lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
827 return DWARF_CB_ABORT;
833 * die_walk_lines - Walk on lines inside given DIE
834 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
835 * @callback: callback routine
838 * Walk on all lines inside given @rt_die and call @callback on each line.
839 * If the @rt_die is a function, walk only on the lines inside the function,
840 * otherwise @rt_die must be a CU DIE.
841 * Note that this walks not only dwarf line list, but also function entries
842 * and inline call-site.
844 int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
849 const char *fname, *decf = NULL, *inf = NULL;
852 Dwarf_Die die_mem, *cu_die;
857 if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
858 cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
859 dwarf_decl_line(rt_die, &decl);
860 decf = dwarf_decl_file(rt_die);
864 pr_debug2("Failed to get CU from given DIE.\n");
868 /* Get lines list in the CU */
869 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
870 pr_debug2("Failed to get source lines on this CU.\n");
873 pr_debug2("Get %zd lines from this CU\n", nlines);
875 /* Walk on the lines on lines list */
876 for (i = 0; i < nlines; i++) {
877 line = dwarf_onesrcline(lines, i);
879 dwarf_lineno(line, &lineno) != 0 ||
880 dwarf_lineaddr(line, &addr) != 0) {
881 pr_debug2("Failed to get line info. "
882 "Possible error in debuginfo.\n");
885 /* Skip end-of-sequence */
886 if (dwarf_lineendsequence(line, &flag) != 0 || flag)
888 /* Skip Non statement line-info */
889 if (dwarf_linebeginstatement(line, &flag) != 0 || !flag)
891 /* Filter lines based on address */
892 if (rt_die != cu_die) {
895 * The line is included in given function, and
896 * no inline block includes it.
898 if (!dwarf_haspc(rt_die, addr))
901 if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
902 /* Call-site check */
903 inf = die_get_call_file(&die_mem);
904 if ((inf && !strcmp(inf, decf)) &&
905 die_get_call_lineno(&die_mem) == lineno)
908 dwarf_decl_line(&die_mem, &inl);
910 decf != dwarf_decl_file(&die_mem))
915 /* Get source line */
916 fname = dwarf_linesrc(line, NULL, NULL);
918 ret = callback(fname, lineno, addr, data);
924 * Dwarf lines doesn't include function declarations and inlined
925 * subroutines. We have to check functions list or given function.
927 if (rt_die != cu_die)
929 * Don't need walk inlined functions recursively, because
930 * inner inlined functions don't have the lines of the
931 * specified function.
933 ret = __die_walk_funclines(rt_die, false, callback, data);
935 struct __line_walk_param param = {
936 .callback = callback,
940 dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
947 struct __find_variable_param {
952 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
954 struct __find_variable_param *fvp = data;
955 Dwarf_Attribute attr;
958 tag = dwarf_tag(die_mem);
959 if ((tag == DW_TAG_formal_parameter ||
960 tag == DW_TAG_variable) &&
961 die_compare_name(die_mem, fvp->name) &&
962 /* Does the DIE have location information or external instance? */
963 (dwarf_attr(die_mem, DW_AT_external, &attr) ||
964 dwarf_attr(die_mem, DW_AT_location, &attr)))
965 return DIE_FIND_CB_END;
966 if (dwarf_haspc(die_mem, fvp->addr))
967 return DIE_FIND_CB_CONTINUE;
969 return DIE_FIND_CB_SIBLING;
973 * die_find_variable_at - Find a given name variable at given address
974 * @sp_die: a function DIE
975 * @name: variable name
977 * @die_mem: a buffer for result DIE
979 * Find a variable DIE called @name at @addr in @sp_die.
981 Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
982 Dwarf_Addr addr, Dwarf_Die *die_mem)
984 struct __find_variable_param fvp = { .name = name, .addr = addr};
986 return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
990 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
992 const char *name = data;
994 if (dwarf_tag(die_mem) == DW_TAG_member) {
995 if (die_compare_name(die_mem, name))
996 return DIE_FIND_CB_END;
997 else if (!dwarf_diename(die_mem)) { /* Unnamed structure */
998 Dwarf_Die type_die, tmp_die;
999 if (die_get_type(die_mem, &type_die) &&
1000 die_find_member(&type_die, name, &tmp_die))
1001 return DIE_FIND_CB_END;
1004 return DIE_FIND_CB_SIBLING;
1008 * die_find_member - Find a given name member in a data structure
1009 * @st_die: a data structure type DIE
1010 * @name: member name
1011 * @die_mem: a buffer for result DIE
1013 * Find a member DIE called @name in @st_die.
1015 Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
1018 return die_find_child(st_die, __die_find_member_cb, (void *)name,
1023 * die_get_typename - Get the name of given variable DIE
1024 * @vr_die: a variable DIE
1025 * @buf: a strbuf for result type name
1027 * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
1028 * and Return -ENOENT if failed to find type name.
1029 * Note that the result will stores typedef name if possible, and stores
1030 * "*(function_type)" if the type is a function pointer.
1032 int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
1036 const char *tmp = "";
1038 if (__die_get_real_type(vr_die, &type) == NULL)
1041 tag = dwarf_tag(&type);
1042 if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
1044 else if (tag == DW_TAG_subroutine_type) {
1045 /* Function pointer */
1046 return strbuf_add(buf, "(function_type)", 15);
1048 if (!dwarf_diename(&type))
1050 if (tag == DW_TAG_union_type)
1052 else if (tag == DW_TAG_structure_type)
1054 else if (tag == DW_TAG_enumeration_type)
1056 /* Write a base name */
1057 return strbuf_addf(buf, "%s%s", tmp, dwarf_diename(&type));
1059 ret = die_get_typename(&type, buf);
1060 return ret ? ret : strbuf_addstr(buf, tmp);
1064 * die_get_varname - Get the name and type of given variable DIE
1065 * @vr_die: a variable DIE
1066 * @buf: a strbuf for type and variable name
1068 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
1070 int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
1074 ret = die_get_typename(vr_die, buf);
1076 pr_debug("Failed to get type, make it unknown.\n");
1077 ret = strbuf_add(buf, " (unknown_type)", 14);
1080 return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
1083 #ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT
1085 * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
1086 * @sp_die: a subprogram DIE
1087 * @vr_die: a variable DIE
1088 * @buf: a strbuf for variable byte offset range
1090 * Get the innermost scope range of @vr_die and stores it in @buf as
1091 * "@<function_name+[NN-NN,NN-NN]>".
1093 static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
1100 Dwarf_Addr start, end;
1106 ret = die_entrypc(sp_die, &entry);
1110 name = dwarf_diename(sp_die);
1114 count = dwarf_getscopes_die(vr_die, &scopes);
1116 /* (*SCOPES)[1] is the DIE for the scope containing that scope */
1122 while ((offset = dwarf_ranges(&scopes[1], offset, &base,
1123 &start, &end)) > 0) {
1128 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1132 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1140 ret = strbuf_add(buf, "]>", 2);
1148 * die_get_var_range - Get byte offset range of given variable DIE
1149 * @sp_die: a subprogram DIE
1150 * @vr_die: a variable DIE
1151 * @buf: a strbuf for type and variable name and byte offset range
1153 * Get the byte offset range of @vr_die and stores it in @buf as
1154 * "@<function_name+[NN-NN,NN-NN]>".
1156 int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
1160 Dwarf_Addr start, end;
1165 Dwarf_Attribute attr;
1169 ret = die_entrypc(sp_die, &entry);
1173 name = dwarf_diename(sp_die);
1177 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
1180 while ((offset = dwarf_getlocations(&attr, offset, &base,
1181 &start, &end, &op, &nops)) > 0) {
1183 /* Single Location Descriptions */
1184 ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
1188 /* Location Lists */
1192 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1196 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1204 ret = strbuf_add(buf, "]>", 2);
1209 int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
1210 Dwarf_Die *vr_die __maybe_unused,
1211 struct strbuf *buf __maybe_unused)
1218 * die_has_loclist - Check if DW_AT_location of @vr_die is a location list
1219 * @vr_die: a variable DIE
1221 static bool die_has_loclist(Dwarf_Die *vr_die)
1223 Dwarf_Attribute loc;
1224 int tag = dwarf_tag(vr_die);
1226 if (tag != DW_TAG_formal_parameter &&
1227 tag != DW_TAG_variable)
1230 return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
1231 dwarf_whatform(&loc) == DW_FORM_sec_offset);
1235 * die_is_optimized_target - Check if target program is compiled with
1239 * For any object in given CU whose DW_AT_location is a location list,
1240 * target program is compiled with optimization. This is applicable to
1243 bool die_is_optimized_target(Dwarf_Die *cu_die)
1247 if (die_has_loclist(cu_die))
1250 if (!dwarf_child(cu_die, &tmp_die) &&
1251 die_is_optimized_target(&tmp_die))
1254 if (!dwarf_siblingof(cu_die, &tmp_die) &&
1255 die_is_optimized_target(&tmp_die))
1262 * die_search_idx - Search index of given line address
1263 * @lines: Line records of single CU
1264 * @nr_lines: Number of @lines
1265 * @addr: address we are looking for
1266 * @idx: index to be set by this function (return value)
1268 * Search for @addr by looping over every lines of CU. If address
1269 * matches, set index of that line in @idx. Note that single source
1270 * line can have multiple line records. i.e. single source line can
1271 * have multiple index.
1273 static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
1274 Dwarf_Addr addr, unsigned long *idx)
1279 for (i = 0; i < nr_lines; i++) {
1280 if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
1292 * die_get_postprologue_addr - Search next address after function prologue
1293 * @entrypc_idx: entrypc index
1294 * @lines: Line records of single CU
1295 * @nr_lines: Number of @lines
1296 * @hignpc: high PC address of function
1297 * @postprologue_addr: Next address after function prologue (return value)
1299 * Look for prologue-end marker. If there is no explicit marker, return
1300 * address of next line record or next source line.
1302 static bool die_get_postprologue_addr(unsigned long entrypc_idx,
1304 unsigned long nr_lines,
1306 Dwarf_Addr *postprologue_addr)
1309 int entrypc_lno, lno;
1314 /* entrypc_lno is actual source line number */
1315 line = dwarf_onesrcline(lines, entrypc_idx);
1316 if (dwarf_lineno(line, &entrypc_lno))
1319 for (i = entrypc_idx; i < nr_lines; i++) {
1320 line = dwarf_onesrcline(lines, i);
1322 if (dwarf_lineaddr(line, &addr) ||
1323 dwarf_lineno(line, &lno) ||
1324 dwarf_lineprologueend(line, &p_end))
1327 /* highpc is exclusive. [entrypc,highpc) */
1331 /* clang supports prologue-end marker */
1335 /* Actual next line in source */
1336 if (lno != entrypc_lno)
1340 * Single source line can have multiple line records.
1342 * void foo() { printf("hello\n"); }
1343 * contains two line records. One points to declaration and
1344 * other points to printf() line. Variable 'lno' won't get
1345 * incremented in this case but 'i' will.
1347 if (i != entrypc_idx)
1351 dwarf_lineaddr(line, postprologue_addr);
1352 if (*postprologue_addr >= highpc)
1353 dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
1360 * die_skip_prologue - Use next address after prologue as probe location
1361 * @sp_die: a subprogram DIE
1363 * @entrypc: entrypc of the function
1365 * Function prologue prepares stack and registers before executing function
1366 * logic. When target program is compiled without optimization, function
1367 * parameter information is only valid after prologue. When we probe entrypc
1368 * of the function, and try to record function parameter, it contains
1371 void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
1372 Dwarf_Addr *entrypc)
1374 size_t nr_lines = 0;
1375 unsigned long entrypc_idx = 0;
1376 Dwarf_Lines *lines = NULL;
1377 Dwarf_Addr postprologue_addr;
1380 if (dwarf_highpc(sp_die, &highpc))
1383 if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
1386 if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
1389 if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
1390 highpc, &postprologue_addr))
1393 *entrypc = postprologue_addr;