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;
380 if (dwarf_entrypc(dw_die, addr) == 0)
383 return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;
387 * die_is_func_instance - Ensure that this DIE is an instance of a subprogram
390 * Ensure that this DIE is an instance (which has an entry address).
391 * This returns true if @dw_die is a function instance. If not, the @dw_die
392 * must be a prototype. You can use die_walk_instances() to find actual
395 bool die_is_func_instance(Dwarf_Die *dw_die)
398 Dwarf_Attribute attr_mem;
399 int tag = dwarf_tag(dw_die);
401 if (tag != DW_TAG_subprogram &&
402 tag != DW_TAG_inlined_subroutine)
405 return dwarf_entrypc(dw_die, &tmp) == 0 ||
406 dwarf_attr(dw_die, DW_AT_ranges, &attr_mem) != NULL;
410 * die_get_data_member_location - Get the data-member offset
411 * @mb_die: a DIE of a member of a data structure
412 * @offs: The offset of the member in the data structure
414 * Get the offset of @mb_die in the data structure including @mb_die, and
415 * stores result offset to @offs. If any error occurs this returns errno.
417 int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
419 Dwarf_Attribute attr;
424 if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
427 if (dwarf_formudata(&attr, offs) != 0) {
428 /* DW_AT_data_member_location should be DW_OP_plus_uconst */
429 ret = dwarf_getlocation(&attr, &expr, &nexpr);
430 if (ret < 0 || nexpr == 0)
433 if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
434 pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
435 expr[0].atom, nexpr);
438 *offs = (Dwarf_Word)expr[0].number;
443 /* Get the call file index number in CU DIE */
444 static int die_get_call_fileno(Dwarf_Die *in_die)
448 if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0)
454 /* Get the declared file index number in CU DIE */
455 static int die_get_decl_fileno(Dwarf_Die *pdie)
459 if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0)
466 * die_get_call_file - Get callsite file name of inlined function instance
467 * @in_die: a DIE of an inlined function instance
469 * Get call-site file name of @in_die. This means from which file the inline
470 * function is called.
472 const char *die_get_call_file(Dwarf_Die *in_die)
478 idx = die_get_call_fileno(in_die);
479 if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
480 dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
483 return dwarf_filesrc(files, idx, NULL, NULL);
488 * die_find_child - Generic DIE search function in DIE tree
489 * @rt_die: a root DIE
490 * @callback: a callback function
491 * @data: a user data passed to the callback function
492 * @die_mem: a buffer for result DIE
494 * Trace DIE tree from @rt_die and call @callback for each child DIE.
495 * If @callback returns DIE_FIND_CB_END, this stores the DIE into
496 * @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
497 * this continues to trace the tree. Optionally, @callback can return
498 * DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
499 * the children and trace only the siblings respectively.
500 * Returns NULL if @callback can't find any appropriate DIE.
502 Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
503 int (*callback)(Dwarf_Die *, void *),
504 void *data, Dwarf_Die *die_mem)
509 ret = dwarf_child(rt_die, die_mem);
514 ret = callback(die_mem, data);
515 if (ret == DIE_FIND_CB_END)
518 if ((ret & DIE_FIND_CB_CHILD) &&
519 die_find_child(die_mem, callback, data, &child_die)) {
520 memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
523 } while ((ret & DIE_FIND_CB_SIBLING) &&
524 dwarf_siblingof(die_mem, die_mem) == 0);
529 struct __addr_die_search_param {
534 static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
536 struct __addr_die_search_param *ad = data;
539 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
540 !dwarf_highpc(fn_die, &addr) &&
542 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
543 return DWARF_CB_ABORT;
549 * die_find_tailfunc - Search for a non-inlined function with tail call at
551 * @cu_die: a CU DIE which including @addr
552 * @addr: target address
553 * @die_mem: a buffer for result DIE
555 * Search for a non-inlined function DIE with tail call at @addr. Stores the
556 * DIE to @die_mem and returns it if found. Returns NULL if failed.
558 Dwarf_Die *die_find_tailfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
561 struct __addr_die_search_param ad;
563 ad.die_mem = die_mem;
564 /* dwarf_getscopes can't find subprogram. */
565 if (!dwarf_getfuncs(cu_die, __die_search_func_tail_cb, &ad, 0))
571 /* die_find callback for non-inlined function search */
572 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
574 struct __addr_die_search_param *ad = data;
577 * Since a declaration entry doesn't has given pc, this always returns
578 * function definition entry.
580 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
581 dwarf_haspc(fn_die, ad->addr)) {
582 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
583 return DWARF_CB_ABORT;
589 * die_find_realfunc - Search a non-inlined function at given address
590 * @cu_die: a CU DIE which including @addr
591 * @addr: target address
592 * @die_mem: a buffer for result DIE
594 * Search a non-inlined function DIE which includes @addr. Stores the
595 * DIE to @die_mem and returns it if found. Returns NULL if failed.
597 Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
600 struct __addr_die_search_param ad;
602 ad.die_mem = die_mem;
603 /* dwarf_getscopes can't find subprogram. */
604 if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
610 /* die_find callback for inline function search */
611 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
613 Dwarf_Addr *addr = data;
615 if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
616 dwarf_haspc(die_mem, *addr))
617 return DIE_FIND_CB_END;
619 return DIE_FIND_CB_CONTINUE;
623 * die_find_top_inlinefunc - Search the top inlined function at given address
624 * @sp_die: a subprogram DIE which including @addr
625 * @addr: target address
626 * @die_mem: a buffer for result DIE
628 * Search an inlined function DIE which includes @addr. Stores the
629 * DIE to @die_mem and returns it if found. Returns NULL if failed.
630 * Even if several inlined functions are expanded recursively, this
631 * doesn't trace it down, and returns the topmost one.
633 Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
636 return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
640 * die_find_inlinefunc - Search an inlined function at given address
641 * @sp_die: a subprogram DIE which including @addr
642 * @addr: target address
643 * @die_mem: a buffer for result DIE
645 * Search an inlined function DIE which includes @addr. Stores the
646 * DIE to @die_mem and returns it if found. Returns NULL if failed.
647 * If several inlined functions are expanded recursively, this trace
648 * it down and returns deepest one.
650 Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
655 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
659 /* Inlined function could be recursive. Trace it until fail */
661 memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
662 sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
669 struct __instance_walk_param {
671 int (*callback)(Dwarf_Die *, void *);
676 static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
678 struct __instance_walk_param *iwp = data;
679 Dwarf_Attribute attr_mem;
680 Dwarf_Die origin_mem;
681 Dwarf_Attribute *attr;
685 if (!die_is_func_instance(inst))
686 return DIE_FIND_CB_CONTINUE;
688 attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
690 return DIE_FIND_CB_CONTINUE;
692 origin = dwarf_formref_die(attr, &origin_mem);
693 if (origin == NULL || origin->addr != iwp->addr)
694 return DIE_FIND_CB_CONTINUE;
696 /* Ignore redundant instances */
697 if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
698 dwarf_decl_line(origin, &tmp);
699 if (die_get_call_lineno(inst) == tmp) {
700 tmp = die_get_decl_fileno(origin);
701 if (die_get_call_fileno(inst) == tmp)
702 return DIE_FIND_CB_CONTINUE;
706 iwp->retval = iwp->callback(inst, iwp->data);
708 return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
712 * die_walk_instances - Walk on instances of given DIE
713 * @or_die: an abstract original DIE
714 * @callback: a callback function which is called with instance DIE
717 * Walk on the instances of give @in_die. @in_die must be an inlined function
718 * declartion. This returns the return value of @callback if it returns
719 * non-zero value, or -ENOENT if there is no instance.
721 int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
726 struct __instance_walk_param iwp = {
727 .addr = or_die->addr,
728 .callback = callback,
733 if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
736 die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
741 /* Line walker internal parameters */
742 struct __line_walk_param {
744 line_walk_callback_t callback;
749 static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
751 struct __line_walk_param *lw = data;
756 if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
757 fname = die_get_call_file(in_die);
758 lineno = die_get_call_lineno(in_die);
759 if (fname && lineno > 0 && die_entrypc(in_die, &addr) == 0) {
760 lw->retval = lw->callback(fname, lineno, addr, lw->data);
762 return DIE_FIND_CB_END;
765 return DIE_FIND_CB_SIBLING;
769 fname = dwarf_decl_file(in_die);
770 if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
771 lw->retval = lw->callback(fname, lineno, addr, lw->data);
773 return DIE_FIND_CB_END;
777 /* Continue to search nested inlined function call-sites */
778 return DIE_FIND_CB_CONTINUE;
781 /* Walk on lines of blocks included in given DIE */
782 static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
783 line_walk_callback_t callback, void *data)
785 struct __line_walk_param lw = {
786 .recursive = recursive,
787 .callback = callback,
796 /* Handle function declaration line */
797 fname = dwarf_decl_file(sp_die);
798 if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
799 die_entrypc(sp_die, &addr) == 0) {
800 lw.retval = callback(fname, lineno, addr, data);
804 die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
809 static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
811 struct __line_walk_param *lw = data;
814 * Since inlined function can include another inlined function in
815 * the same file, we need to walk in it recursively.
817 lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
819 return DWARF_CB_ABORT;
825 * die_walk_lines - Walk on lines inside given DIE
826 * @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
827 * @callback: callback routine
830 * Walk on all lines inside given @rt_die and call @callback on each line.
831 * If the @rt_die is a function, walk only on the lines inside the function,
832 * otherwise @rt_die must be a CU DIE.
833 * Note that this walks not only dwarf line list, but also function entries
834 * and inline call-site.
836 int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
841 const char *fname, *decf = NULL, *inf = NULL;
844 Dwarf_Die die_mem, *cu_die;
849 if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
850 cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
851 dwarf_decl_line(rt_die, &decl);
852 decf = dwarf_decl_file(rt_die);
856 pr_debug2("Failed to get CU from given DIE.\n");
860 /* Get lines list in the CU */
861 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
862 pr_debug2("Failed to get source lines on this CU.\n");
865 pr_debug2("Get %zd lines from this CU\n", nlines);
867 /* Walk on the lines on lines list */
868 for (i = 0; i < nlines; i++) {
869 line = dwarf_onesrcline(lines, i);
871 dwarf_lineno(line, &lineno) != 0 ||
872 dwarf_lineaddr(line, &addr) != 0) {
873 pr_debug2("Failed to get line info. "
874 "Possible error in debuginfo.\n");
877 /* Skip end-of-sequence */
878 if (dwarf_lineendsequence(line, &flag) != 0 || flag)
880 /* Skip Non statement line-info */
881 if (dwarf_linebeginstatement(line, &flag) != 0 || !flag)
883 /* Filter lines based on address */
884 if (rt_die != cu_die) {
887 * The line is included in given function, and
888 * no inline block includes it.
890 if (!dwarf_haspc(rt_die, addr))
893 if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
894 /* Call-site check */
895 inf = die_get_call_file(&die_mem);
896 if ((inf && !strcmp(inf, decf)) &&
897 die_get_call_lineno(&die_mem) == lineno)
900 dwarf_decl_line(&die_mem, &inl);
902 decf != dwarf_decl_file(&die_mem))
907 /* Get source line */
908 fname = dwarf_linesrc(line, NULL, NULL);
910 ret = callback(fname, lineno, addr, data);
916 * Dwarf lines doesn't include function declarations and inlined
917 * subroutines. We have to check functions list or given function.
919 if (rt_die != cu_die)
921 * Don't need walk inlined functions recursively, because
922 * inner inlined functions don't have the lines of the
923 * specified function.
925 ret = __die_walk_funclines(rt_die, false, callback, data);
927 struct __line_walk_param param = {
928 .callback = callback,
932 dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
939 struct __find_variable_param {
944 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
946 struct __find_variable_param *fvp = data;
947 Dwarf_Attribute attr;
950 tag = dwarf_tag(die_mem);
951 if ((tag == DW_TAG_formal_parameter ||
952 tag == DW_TAG_variable) &&
953 die_compare_name(die_mem, fvp->name) &&
954 /* Does the DIE have location information or external instance? */
955 (dwarf_attr(die_mem, DW_AT_external, &attr) ||
956 dwarf_attr(die_mem, DW_AT_location, &attr)))
957 return DIE_FIND_CB_END;
958 if (dwarf_haspc(die_mem, fvp->addr))
959 return DIE_FIND_CB_CONTINUE;
961 return DIE_FIND_CB_SIBLING;
965 * die_find_variable_at - Find a given name variable at given address
966 * @sp_die: a function DIE
967 * @name: variable name
969 * @die_mem: a buffer for result DIE
971 * Find a variable DIE called @name at @addr in @sp_die.
973 Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
974 Dwarf_Addr addr, Dwarf_Die *die_mem)
976 struct __find_variable_param fvp = { .name = name, .addr = addr};
978 return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
982 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
984 const char *name = data;
986 if (dwarf_tag(die_mem) == DW_TAG_member) {
987 if (die_compare_name(die_mem, name))
988 return DIE_FIND_CB_END;
989 else if (!dwarf_diename(die_mem)) { /* Unnamed structure */
990 Dwarf_Die type_die, tmp_die;
991 if (die_get_type(die_mem, &type_die) &&
992 die_find_member(&type_die, name, &tmp_die))
993 return DIE_FIND_CB_END;
996 return DIE_FIND_CB_SIBLING;
1000 * die_find_member - Find a given name member in a data structure
1001 * @st_die: a data structure type DIE
1002 * @name: member name
1003 * @die_mem: a buffer for result DIE
1005 * Find a member DIE called @name in @st_die.
1007 Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
1010 return die_find_child(st_die, __die_find_member_cb, (void *)name,
1015 * die_get_typename - Get the name of given variable DIE
1016 * @vr_die: a variable DIE
1017 * @buf: a strbuf for result type name
1019 * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
1020 * and Return -ENOENT if failed to find type name.
1021 * Note that the result will stores typedef name if possible, and stores
1022 * "*(function_type)" if the type is a function pointer.
1024 int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
1028 const char *tmp = "";
1030 if (__die_get_real_type(vr_die, &type) == NULL)
1033 tag = dwarf_tag(&type);
1034 if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
1036 else if (tag == DW_TAG_subroutine_type) {
1037 /* Function pointer */
1038 return strbuf_add(buf, "(function_type)", 15);
1040 if (!dwarf_diename(&type))
1042 if (tag == DW_TAG_union_type)
1044 else if (tag == DW_TAG_structure_type)
1046 else if (tag == DW_TAG_enumeration_type)
1048 /* Write a base name */
1049 return strbuf_addf(buf, "%s%s", tmp, dwarf_diename(&type));
1051 ret = die_get_typename(&type, buf);
1052 return ret ? ret : strbuf_addstr(buf, tmp);
1056 * die_get_varname - Get the name and type of given variable DIE
1057 * @vr_die: a variable DIE
1058 * @buf: a strbuf for type and variable name
1060 * Get the name and type of @vr_die and stores it in @buf as "type\tname".
1062 int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
1066 ret = die_get_typename(vr_die, buf);
1068 pr_debug("Failed to get type, make it unknown.\n");
1069 ret = strbuf_add(buf, " (unknown_type)", 14);
1072 return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
1075 #ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT
1077 * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
1078 * @sp_die: a subprogram DIE
1079 * @vr_die: a variable DIE
1080 * @buf: a strbuf for variable byte offset range
1082 * Get the innermost scope range of @vr_die and stores it in @buf as
1083 * "@<function_name+[NN-NN,NN-NN]>".
1085 static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
1092 Dwarf_Addr start, end;
1098 ret = die_entrypc(sp_die, &entry);
1102 name = dwarf_diename(sp_die);
1106 count = dwarf_getscopes_die(vr_die, &scopes);
1108 /* (*SCOPES)[1] is the DIE for the scope containing that scope */
1114 while ((offset = dwarf_ranges(&scopes[1], offset, &base,
1115 &start, &end)) > 0) {
1120 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1124 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1132 ret = strbuf_add(buf, "]>", 2);
1140 * die_get_var_range - Get byte offset range of given variable DIE
1141 * @sp_die: a subprogram DIE
1142 * @vr_die: a variable DIE
1143 * @buf: a strbuf for type and variable name and byte offset range
1145 * Get the byte offset range of @vr_die and stores it in @buf as
1146 * "@<function_name+[NN-NN,NN-NN]>".
1148 int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
1152 Dwarf_Addr start, end;
1157 Dwarf_Attribute attr;
1161 ret = die_entrypc(sp_die, &entry);
1165 name = dwarf_diename(sp_die);
1169 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
1172 while ((offset = dwarf_getlocations(&attr, offset, &base,
1173 &start, &end, &op, &nops)) > 0) {
1175 /* Single Location Descriptions */
1176 ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
1180 /* Location Lists */
1184 ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
1188 ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
1196 ret = strbuf_add(buf, "]>", 2);
1201 int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
1202 Dwarf_Die *vr_die __maybe_unused,
1203 struct strbuf *buf __maybe_unused)
1210 * die_has_loclist - Check if DW_AT_location of @vr_die is a location list
1211 * @vr_die: a variable DIE
1213 static bool die_has_loclist(Dwarf_Die *vr_die)
1215 Dwarf_Attribute loc;
1216 int tag = dwarf_tag(vr_die);
1218 if (tag != DW_TAG_formal_parameter &&
1219 tag != DW_TAG_variable)
1222 return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
1223 dwarf_whatform(&loc) == DW_FORM_sec_offset);
1227 * die_is_optimized_target - Check if target program is compiled with
1231 * For any object in given CU whose DW_AT_location is a location list,
1232 * target program is compiled with optimization. This is applicable to
1235 bool die_is_optimized_target(Dwarf_Die *cu_die)
1239 if (die_has_loclist(cu_die))
1242 if (!dwarf_child(cu_die, &tmp_die) &&
1243 die_is_optimized_target(&tmp_die))
1246 if (!dwarf_siblingof(cu_die, &tmp_die) &&
1247 die_is_optimized_target(&tmp_die))
1254 * die_search_idx - Search index of given line address
1255 * @lines: Line records of single CU
1256 * @nr_lines: Number of @lines
1257 * @addr: address we are looking for
1258 * @idx: index to be set by this function (return value)
1260 * Search for @addr by looping over every lines of CU. If address
1261 * matches, set index of that line in @idx. Note that single source
1262 * line can have multiple line records. i.e. single source line can
1263 * have multiple index.
1265 static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
1266 Dwarf_Addr addr, unsigned long *idx)
1271 for (i = 0; i < nr_lines; i++) {
1272 if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
1284 * die_get_postprologue_addr - Search next address after function prologue
1285 * @entrypc_idx: entrypc index
1286 * @lines: Line records of single CU
1287 * @nr_lines: Number of @lines
1288 * @hignpc: high PC address of function
1289 * @postprologue_addr: Next address after function prologue (return value)
1291 * Look for prologue-end marker. If there is no explicit marker, return
1292 * address of next line record or next source line.
1294 static bool die_get_postprologue_addr(unsigned long entrypc_idx,
1296 unsigned long nr_lines,
1298 Dwarf_Addr *postprologue_addr)
1301 int entrypc_lno, lno;
1306 /* entrypc_lno is actual source line number */
1307 line = dwarf_onesrcline(lines, entrypc_idx);
1308 if (dwarf_lineno(line, &entrypc_lno))
1311 for (i = entrypc_idx; i < nr_lines; i++) {
1312 line = dwarf_onesrcline(lines, i);
1314 if (dwarf_lineaddr(line, &addr) ||
1315 dwarf_lineno(line, &lno) ||
1316 dwarf_lineprologueend(line, &p_end))
1319 /* highpc is exclusive. [entrypc,highpc) */
1323 /* clang supports prologue-end marker */
1327 /* Actual next line in source */
1328 if (lno != entrypc_lno)
1332 * Single source line can have multiple line records.
1334 * void foo() { printf("hello\n"); }
1335 * contains two line records. One points to declaration and
1336 * other points to printf() line. Variable 'lno' won't get
1337 * incremented in this case but 'i' will.
1339 if (i != entrypc_idx)
1343 dwarf_lineaddr(line, postprologue_addr);
1344 if (*postprologue_addr >= highpc)
1345 dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
1352 * die_skip_prologue - Use next address after prologue as probe location
1353 * @sp_die: a subprogram DIE
1355 * @entrypc: entrypc of the function
1357 * Function prologue prepares stack and registers before executing function
1358 * logic. When target program is compiled without optimization, function
1359 * parameter information is only valid after prologue. When we probe entrypc
1360 * of the function, and try to record function parameter, it contains
1363 void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
1364 Dwarf_Addr *entrypc)
1366 size_t nr_lines = 0;
1367 unsigned long entrypc_idx = 0;
1368 Dwarf_Lines *lines = NULL;
1369 Dwarf_Addr postprologue_addr;
1372 if (dwarf_highpc(sp_die, &highpc))
1375 if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
1378 if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
1381 if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
1382 highpc, &postprologue_addr))
1385 *entrypc = postprologue_addr;