2 * probe-finder.c : C expression to kprobe event converter
4 * Written by Masami Hiramatsu <mhiramat@redhat.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22 #include <sys/utsname.h>
23 #include <sys/types.h>
32 #include <dwarf-regs.h>
34 #include <linux/bitops.h>
41 #include "probe-finder.h"
43 /* Kprobe tracer basic type is up to u64 */
44 #define MAX_BASIC_TYPE_BITS 64
46 /* Dwarf FL wrappers */
47 static char *debuginfo_path; /* Currently dummy */
49 static const Dwfl_Callbacks offline_callbacks = {
50 .find_debuginfo = dwfl_standard_find_debuginfo,
51 .debuginfo_path = &debuginfo_path,
53 .section_address = dwfl_offline_section_address,
55 /* We use this table for core files too. */
56 .find_elf = dwfl_build_id_find_elf,
59 /* Get a Dwarf from offline image */
60 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
65 fd = open(path, O_RDONLY);
69 dbg->dwfl = dwfl_begin(&offline_callbacks);
73 dwfl_report_begin(dbg->dwfl);
74 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
78 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
82 dwfl_report_end(dbg->dwfl, NULL, NULL);
90 memset(dbg, 0, sizeof(*dbg));
95 static struct debuginfo *__debuginfo__new(const char *path)
97 struct debuginfo *dbg = zalloc(sizeof(*dbg));
101 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
104 pr_debug("Open Debuginfo file: %s\n", path);
108 enum dso_binary_type distro_dwarf_types[] = {
109 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
110 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
111 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
112 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
113 DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO,
114 DSO_BINARY_TYPE__NOT_FOUND,
117 struct debuginfo *debuginfo__new(const char *path)
119 enum dso_binary_type *type;
120 char buf[PATH_MAX], nil = '\0';
122 struct debuginfo *dinfo = NULL;
124 /* Try to open distro debuginfo files */
125 dso = dso__new(path);
129 for (type = distro_dwarf_types;
130 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
132 if (dso__read_binary_type_filename(dso, *type, &nil,
135 dinfo = __debuginfo__new(buf);
140 /* if failed to open all distro debuginfo, open given binary */
141 return dinfo ? : __debuginfo__new(path);
144 void debuginfo__delete(struct debuginfo *dbg)
154 * Probe finder related functions
157 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
159 struct probe_trace_arg_ref *ref;
160 ref = zalloc(sizeof(struct probe_trace_arg_ref));
167 * Convert a location into trace_arg.
168 * If tvar == NULL, this just checks variable can be converted.
169 * If fentry == true and vr_die is a parameter, do huristic search
170 * for the location fuzzed by function entry mcount.
172 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
173 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
174 struct probe_trace_arg *tvar)
176 Dwarf_Attribute attr;
186 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
189 /* TODO: handle more than 1 exprs */
190 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
191 return -EINVAL; /* Broken DIE ? */
192 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
193 ret = dwarf_entrypc(sp_die, &tmp);
197 if (probe_conf.show_location_range &&
198 (dwarf_tag(vr_die) == DW_TAG_variable)) {
200 } else if (addr != tmp ||
201 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
205 ret = dwarf_highpc(sp_die, &tmp);
209 * This is fuzzed by fentry mcount. We try to find the
210 * parameter location at the earliest address.
212 for (addr += 1; addr <= tmp; addr++) {
213 if (dwarf_getlocation_addr(&attr, addr, &op,
221 /* TODO: Support const_value */
224 if (op->atom == DW_OP_addr) {
228 /* Static variables on memory (not stack), make @varname */
229 ret = strlen(dwarf_diename(vr_die));
230 tvar->value = zalloc(ret + 2);
231 if (tvar->value == NULL)
233 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
234 tvar->ref = alloc_trace_arg_ref((long)offs);
235 if (tvar->ref == NULL)
240 /* If this is based on frame buffer, set the offset */
241 if (op->atom == DW_OP_fbreg) {
249 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
250 regn = op->atom - DW_OP_breg0;
253 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
254 regn = op->atom - DW_OP_reg0;
255 } else if (op->atom == DW_OP_bregx) {
259 } else if (op->atom == DW_OP_regx) {
262 pr_debug("DW_OP %x is not supported.\n", op->atom);
269 regs = get_arch_regstr(regn);
271 /* This should be a bug in DWARF or this tool */
272 pr_warning("Mapping for the register number %u "
273 "missing on this architecture.\n", regn);
277 tvar->value = strdup(regs);
278 if (tvar->value == NULL)
282 tvar->ref = alloc_trace_arg_ref((long)offs);
283 if (tvar->ref == NULL)
289 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
291 static int convert_variable_type(Dwarf_Die *vr_die,
292 struct probe_trace_arg *tvar,
295 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
298 char sbuf[STRERR_BUFSIZE];
299 int bsize, boffs, total;
302 /* TODO: check all types */
303 if (cast && strcmp(cast, "string") != 0) {
304 /* Non string type is OK */
305 tvar->type = strdup(cast);
306 return (tvar->type == NULL) ? -ENOMEM : 0;
309 bsize = dwarf_bitsize(vr_die);
311 /* This is a bitfield */
312 boffs = dwarf_bitoffset(vr_die);
313 total = dwarf_bytesize(vr_die);
314 if (boffs < 0 || total < 0)
316 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
317 BYTES_TO_BITS(total));
321 if (die_get_real_type(vr_die, &type) == NULL) {
322 pr_warning("Failed to get a type information of %s.\n",
323 dwarf_diename(vr_die));
327 pr_debug("%s type is %s.\n",
328 dwarf_diename(vr_die), dwarf_diename(&type));
330 if (cast && strcmp(cast, "string") == 0) { /* String type */
331 ret = dwarf_tag(&type);
332 if (ret != DW_TAG_pointer_type &&
333 ret != DW_TAG_array_type) {
334 pr_warning("Failed to cast into string: "
335 "%s(%s) is not a pointer nor array.\n",
336 dwarf_diename(vr_die), dwarf_diename(&type));
339 if (die_get_real_type(&type, &type) == NULL) {
340 pr_warning("Failed to get a type"
344 if (ret == DW_TAG_pointer_type) {
346 ref_ptr = &(*ref_ptr)->next;
347 /* Add new reference with offset +0 */
348 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
349 if (*ref_ptr == NULL) {
350 pr_warning("Out of memory error\n");
354 if (!die_compare_name(&type, "char") &&
355 !die_compare_name(&type, "unsigned char")) {
356 pr_warning("Failed to cast into string: "
357 "%s is not (unsigned) char *.\n",
358 dwarf_diename(vr_die));
361 tvar->type = strdup(cast);
362 return (tvar->type == NULL) ? -ENOMEM : 0;
365 ret = dwarf_bytesize(&type);
367 /* No size ... try to use default type */
369 ret = BYTES_TO_BITS(ret);
371 /* Check the bitwidth */
372 if (ret > MAX_BASIC_TYPE_BITS) {
373 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
374 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
375 ret = MAX_BASIC_TYPE_BITS;
377 ret = snprintf(buf, 16, "%c%d",
378 die_is_signed_type(&type) ? 's' : 'u', ret);
381 if (ret < 0 || ret >= 16) {
384 pr_warning("Failed to convert variable type: %s\n",
385 strerror_r(-ret, sbuf, sizeof(sbuf)));
388 tvar->type = strdup(buf);
389 if (tvar->type == NULL)
394 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
395 struct perf_probe_arg_field *field,
396 struct probe_trace_arg_ref **ref_ptr,
399 struct probe_trace_arg_ref *ref = *ref_ptr;
404 pr_debug("converting %s in %s\n", field->name, varname);
405 if (die_get_real_type(vr_die, &type) == NULL) {
406 pr_warning("Failed to get the type of %s.\n", varname);
409 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
410 tag = dwarf_tag(&type);
412 if (field->name[0] == '[' &&
413 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
415 /* Save original type for next field */
416 memcpy(die_mem, &type, sizeof(*die_mem));
417 /* Get the type of this array */
418 if (die_get_real_type(&type, &type) == NULL) {
419 pr_warning("Failed to get the type of %s.\n", varname);
422 pr_debug2("Array real type: (%x)\n",
423 (unsigned)dwarf_dieoffset(&type));
424 if (tag == DW_TAG_pointer_type) {
425 ref = zalloc(sizeof(struct probe_trace_arg_ref));
429 (*ref_ptr)->next = ref;
433 ref->offset += dwarf_bytesize(&type) * field->index;
435 /* Save vr_die for converting types */
436 memcpy(die_mem, vr_die, sizeof(*die_mem));
438 } else if (tag == DW_TAG_pointer_type) {
439 /* Check the pointer and dereference */
441 pr_err("Semantic error: %s must be referred by '->'\n",
445 /* Get the type pointed by this pointer */
446 if (die_get_real_type(&type, &type) == NULL) {
447 pr_warning("Failed to get the type of %s.\n", varname);
450 /* Verify it is a data structure */
451 tag = dwarf_tag(&type);
452 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
453 pr_warning("%s is not a data structure nor an union.\n",
458 ref = zalloc(sizeof(struct probe_trace_arg_ref));
462 (*ref_ptr)->next = ref;
466 /* Verify it is a data structure */
467 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
468 pr_warning("%s is not a data structure nor an union.\n",
472 if (field->name[0] == '[') {
473 pr_err("Semantic error: %s is not a pointer"
474 " nor array.\n", varname);
477 /* While prcessing unnamed field, we don't care about this */
478 if (field->ref && dwarf_diename(vr_die)) {
479 pr_err("Semantic error: %s must be referred by '.'\n",
484 pr_warning("Structure on a register is not "
490 if (die_find_member(&type, field->name, die_mem) == NULL) {
491 pr_warning("%s(type:%s) has no member %s.\n", varname,
492 dwarf_diename(&type), field->name);
496 /* Get the offset of the field */
497 if (tag == DW_TAG_union_type) {
500 ret = die_get_data_member_location(die_mem, &offs);
502 pr_warning("Failed to get the offset of %s.\n",
507 ref->offset += (long)offs;
509 /* If this member is unnamed, we need to reuse this field */
510 if (!dwarf_diename(die_mem))
511 return convert_variable_fields(die_mem, varname, field,
515 /* Converting next field */
517 return convert_variable_fields(die_mem, field->name,
518 field->next, &ref, die_mem);
523 /* Show a variables in kprobe event format */
524 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
529 pr_debug("Converting variable %s into trace event.\n",
530 dwarf_diename(vr_die));
532 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
533 &pf->sp_die, pf->tvar);
534 if (ret == -ENOENT || ret == -EINVAL) {
535 pr_err("Failed to find the location of the '%s' variable at this address.\n"
536 " Perhaps it has been optimized out.\n"
537 " Use -V with the --range option to show '%s' location range.\n",
538 pf->pvar->var, pf->pvar->var);
539 } else if (ret == -ENOTSUP)
540 pr_err("Sorry, we don't support this variable location yet.\n");
541 else if (ret == 0 && pf->pvar->field) {
542 ret = convert_variable_fields(vr_die, pf->pvar->var,
543 pf->pvar->field, &pf->tvar->ref,
548 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
549 /* *expr will be cached in libdw. Don't free it. */
553 /* Find a variable in a scope DIE */
554 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
560 /* Copy raw parameters */
561 if (!is_c_varname(pf->pvar->var))
562 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
565 pf->tvar->name = strdup(pf->pvar->name);
567 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
570 ptr = strchr(buf, ':'); /* Change type separator to _ */
573 pf->tvar->name = strdup(buf);
575 if (pf->tvar->name == NULL)
578 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
579 /* Search child die for local variables and parameters. */
580 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
581 /* Search again in global variables */
582 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
584 pr_warning("Failed to find '%s' in this function.\n",
590 ret = convert_variable(&vr_die, pf);
595 /* Convert subprogram DIE to trace point */
596 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
597 Dwarf_Addr paddr, bool retprobe,
598 const char *function,
599 struct probe_trace_point *tp)
605 /* Verify the address is correct */
606 if (!dwarf_haspc(sp_die, paddr)) {
607 pr_warning("Specified offset is out of %s\n",
608 dwarf_diename(sp_die));
612 if (dwarf_entrypc(sp_die, &eaddr) == 0) {
613 /* If the DIE has entrypc, use it. */
614 symbol = dwarf_diename(sp_die);
616 /* Try to get actual symbol name and address from symtab */
617 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
618 eaddr = sym.st_value;
621 pr_warning("Failed to find symbol at 0x%lx\n",
622 (unsigned long)paddr);
626 tp->offset = (unsigned long)(paddr - eaddr);
627 tp->address = (unsigned long)paddr;
628 tp->symbol = strdup(symbol);
632 /* Return probe must be on the head of a subprogram */
634 if (eaddr != paddr) {
635 pr_warning("Failed to find \"%s%%return\",\n"
636 " because %s is an inlined function and"
637 " has no return point.\n", function,
647 /* Call probe_finder callback with scope DIE */
648 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
650 Dwarf_Attribute fb_attr;
655 pr_err("Caller must pass a scope DIE. Program error.\n");
659 /* If not a real subprogram, find a real one */
660 if (!die_is_func_def(sc_die)) {
661 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
662 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
663 pr_warning("Ignoring tail call from %s\n",
664 dwarf_diename(&pf->sp_die));
667 pr_warning("Failed to find probe point in any "
673 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
675 /* Get the frame base attribute/ops from subprogram */
676 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
677 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
678 if (ret <= 0 || nops == 0) {
680 #if _ELFUTILS_PREREQ(0, 142)
681 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
684 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
685 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
686 pr_warning("Failed to get call frame on 0x%jx\n",
687 (uintmax_t)pf->addr);
693 /* Call finder's callback handler */
694 ret = pf->callback(sc_die, pf);
696 /* *pf->fb_ops will be cached in libdw. Don't free it. */
702 struct find_scope_param {
703 const char *function;
711 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
713 struct find_scope_param *fsp = data;
717 /* Skip if declared file name does not match */
719 file = dwarf_decl_file(fn_die);
720 if (!file || strcmp(fsp->file, file) != 0)
723 /* If the function name is given, that's what user expects */
725 if (die_match_name(fn_die, fsp->function)) {
726 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
731 /* With the line number, find the nearest declared DIE */
732 dwarf_decl_line(fn_die, &lno);
733 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
734 /* Keep a candidate and continue */
735 fsp->diff = fsp->line - lno;
736 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
743 /* Return innermost DIE */
744 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
746 struct find_scope_param *fsp = data;
748 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
753 /* Find an appropriate scope fits to given conditions */
754 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
756 struct find_scope_param fsp = {
757 .function = pf->pev->point.function,
766 ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
768 if (!ret && !fsp.found)
769 cu_walk_functions_at(&pf->cu_die, pf->addr,
770 find_inner_scope_cb, &fsp);
772 return fsp.found ? die_mem : NULL;
775 static int probe_point_line_walker(const char *fname, int lineno,
776 Dwarf_Addr addr, void *data)
778 struct probe_finder *pf = data;
779 Dwarf_Die *sc_die, die_mem;
782 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
786 sc_die = find_best_scope(pf, &die_mem);
788 pr_warning("Failed to find scope of probe point.\n");
792 ret = call_probe_finder(sc_die, pf);
794 /* Continue if no error, because the line will be in inline function */
795 return ret < 0 ? ret : 0;
798 /* Find probe point from its line number */
799 static int find_probe_point_by_line(struct probe_finder *pf)
801 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
804 /* Find lines which match lazy pattern */
805 static int find_lazy_match_lines(struct intlist *list,
806 const char *fname, const char *pat)
812 int count = 0, linenum = 1;
813 char sbuf[STRERR_BUFSIZE];
815 fp = fopen(fname, "r");
817 pr_warning("Failed to open %s: %s\n", fname,
818 strerror_r(errno, sbuf, sizeof(sbuf)));
822 while ((len = getline(&line, &line_len, fp)) > 0) {
824 if (line[len - 1] == '\n')
825 line[len - 1] = '\0';
827 if (strlazymatch(line, pat)) {
828 intlist__add(list, linenum);
840 pr_debug("No matched lines found in %s.\n", fname);
844 static int probe_point_lazy_walker(const char *fname, int lineno,
845 Dwarf_Addr addr, void *data)
847 struct probe_finder *pf = data;
848 Dwarf_Die *sc_die, die_mem;
851 if (!intlist__has_entry(pf->lcache, lineno) ||
852 strtailcmp(fname, pf->fname) != 0)
855 pr_debug("Probe line found: line:%d addr:0x%llx\n",
856 lineno, (unsigned long long)addr);
859 sc_die = find_best_scope(pf, &die_mem);
861 pr_warning("Failed to find scope of probe point.\n");
865 ret = call_probe_finder(sc_die, pf);
868 * Continue if no error, because the lazy pattern will match
871 return ret < 0 ? ret : 0;
874 /* Find probe points from lazy pattern */
875 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
880 if (intlist__empty(pf->lcache)) {
881 const char *comp_dir;
883 comp_dir = cu_get_comp_dir(&pf->cu_die);
884 ret = get_real_path(pf->fname, comp_dir, &fpath);
886 pr_warning("Failed to find source file path.\n");
890 /* Matching lazy line pattern */
891 ret = find_lazy_match_lines(pf->lcache, fpath,
892 pf->pev->point.lazy_line);
898 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
901 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
903 struct probe_finder *pf = data;
904 struct perf_probe_point *pp = &pf->pev->point;
909 ret = find_probe_point_lazy(in_die, pf);
911 /* Get probe address */
912 if (die_entrypc(in_die, &addr) != 0) {
913 pr_warning("Failed to get entry address of %s.\n",
914 dwarf_diename(in_die));
918 pf->addr += pp->offset;
919 pr_debug("found inline addr: 0x%jx\n",
920 (uintmax_t)pf->addr);
922 ret = call_probe_finder(in_die, pf);
928 /* Callback parameter with return value for libdw */
929 struct dwarf_callback_param {
934 /* Search function from function name */
935 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
937 struct dwarf_callback_param *param = data;
938 struct probe_finder *pf = param->data;
939 struct perf_probe_point *pp = &pf->pev->point;
941 /* Check tag and diename */
942 if (!die_is_func_def(sp_die) ||
943 !die_match_name(sp_die, pp->function))
946 /* Check declared file */
947 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
950 pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
951 pf->fname = dwarf_decl_file(sp_die);
952 if (pp->line) { /* Function relative line */
953 dwarf_decl_line(sp_die, &pf->lno);
955 param->retval = find_probe_point_by_line(pf);
956 } else if (die_is_func_instance(sp_die)) {
957 /* Instances always have the entry address */
958 dwarf_entrypc(sp_die, &pf->addr);
961 param->retval = find_probe_point_lazy(sp_die, pf);
963 pf->addr += pp->offset;
964 /* TODO: Check the address in this function */
965 param->retval = call_probe_finder(sp_die, pf);
967 } else if (!probe_conf.no_inlines) {
968 /* Inlined function: search instances */
969 param->retval = die_walk_instances(sp_die,
970 probe_point_inline_cb, (void *)pf);
971 /* This could be a non-existed inline definition */
972 if (param->retval == -ENOENT && strisglob(pp->function))
976 /* We need to find other candidates */
977 if (strisglob(pp->function) && param->retval >= 0) {
978 param->retval = 0; /* We have to clear the result */
982 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
985 static int find_probe_point_by_func(struct probe_finder *pf)
987 struct dwarf_callback_param _param = {.data = (void *)pf,
989 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
990 return _param.retval;
993 struct pubname_callback_param {
1001 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1003 struct pubname_callback_param *param = data;
1005 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1006 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1009 if (die_match_name(param->sp_die, param->function)) {
1010 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1014 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1018 return DWARF_CB_ABORT;
1025 /* Find probe points from debuginfo */
1026 static int debuginfo__find_probes(struct debuginfo *dbg,
1027 struct probe_finder *pf)
1029 struct perf_probe_point *pp = &pf->pev->point;
1030 Dwarf_Off off, noff;
1035 #if _ELFUTILS_PREREQ(0, 142)
1040 /* Get the call frame information from this dwarf */
1041 elf = dwarf_getelf(dbg->dbg);
1045 if (gelf_getehdr(elf, &ehdr) == NULL)
1048 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1049 shdr.sh_type == SHT_PROGBITS) {
1050 pf->cfi = dwarf_getcfi_elf(elf);
1052 pf->cfi = dwarf_getcfi(dbg->dbg);
1057 pf->lcache = intlist__new(NULL);
1061 /* Fastpath: lookup by function name from .debug_pubnames section */
1062 if (pp->function && !strisglob(pp->function)) {
1063 struct pubname_callback_param pubname_param = {
1064 .function = pp->function,
1066 .cu_die = &pf->cu_die,
1067 .sp_die = &pf->sp_die,
1070 struct dwarf_callback_param probe_param = {
1074 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1076 if (pubname_param.found) {
1077 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1083 /* Loop on CUs (Compilation Unit) */
1084 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1085 /* Get the DIE(Debugging Information Entry) of this CU */
1086 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1090 /* Check if target file is included. */
1092 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1096 if (!pp->file || pf->fname) {
1098 ret = find_probe_point_by_func(pf);
1099 else if (pp->lazy_line)
1100 ret = find_probe_point_lazy(&pf->cu_die, pf);
1103 ret = find_probe_point_by_line(pf);
1112 intlist__delete(pf->lcache);
1118 struct local_vars_finder {
1119 struct probe_finder *pf;
1120 struct perf_probe_arg *args;
1127 /* Collect available variables in this scope */
1128 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1130 struct local_vars_finder *vf = data;
1131 struct probe_finder *pf = vf->pf;
1134 tag = dwarf_tag(die_mem);
1135 if (tag == DW_TAG_formal_parameter ||
1136 (tag == DW_TAG_variable && vf->vars)) {
1137 if (convert_variable_location(die_mem, vf->pf->addr,
1138 vf->pf->fb_ops, &pf->sp_die,
1140 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1141 if (vf->args[vf->nargs].var == NULL) {
1143 return DIE_FIND_CB_END;
1145 pr_debug(" %s", vf->args[vf->nargs].var);
1150 if (dwarf_haspc(die_mem, vf->pf->addr))
1151 return DIE_FIND_CB_CONTINUE;
1153 return DIE_FIND_CB_SIBLING;
1156 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1157 struct perf_probe_arg *args)
1162 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1163 .max_args = MAX_PROBE_ARGS, .ret = 0};
1165 for (i = 0; i < pf->pev->nargs; i++) {
1166 /* var never be NULL */
1167 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1169 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1170 /* Copy normal argument */
1171 args[n] = pf->pev->args[i];
1175 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1177 /* Special local variables */
1178 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1180 pr_debug(" (%d)\n", vf.nargs - n);
1188 /* Add a found probe point into trace event list */
1189 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1191 struct trace_event_finder *tf =
1192 container_of(pf, struct trace_event_finder, pf);
1193 struct perf_probe_point *pp = &pf->pev->point;
1194 struct probe_trace_event *tev;
1195 struct perf_probe_arg *args = NULL;
1198 /* Check number of tevs */
1199 if (tf->ntevs == tf->max_tevs) {
1200 pr_warning("Too many( > %d) probe point found.\n",
1204 tev = &tf->tevs[tf->ntevs++];
1206 /* Trace point should be converted from subprogram DIE */
1207 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1208 pp->retprobe, pp->function, &tev->point);
1212 tev->point.realname = strdup(dwarf_diename(sc_die));
1213 if (!tev->point.realname) {
1218 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1221 /* Expand special probe argument if exist */
1222 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1228 ret = expand_probe_args(sc_die, pf, args);
1233 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1234 if (tev->args == NULL) {
1239 /* Find each argument */
1240 for (i = 0; i < tev->nargs; i++) {
1241 pf->pvar = &args[i];
1242 pf->tvar = &tev->args[i];
1243 /* Variable should be found from scope DIE */
1244 ret = find_variable(sc_die, pf);
1251 clear_probe_trace_event(tev);
1258 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1259 int debuginfo__find_trace_events(struct debuginfo *dbg,
1260 struct perf_probe_event *pev,
1261 struct probe_trace_event **tevs)
1263 struct trace_event_finder tf = {
1264 .pf = {.pev = pev, .callback = add_probe_trace_event},
1265 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1268 /* Allocate result tevs array */
1269 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1276 ret = debuginfo__find_probes(dbg, &tf.pf);
1277 if (ret < 0 || tf.ntevs == 0) {
1278 for (i = 0; i < tf.ntevs; i++)
1279 clear_probe_trace_event(&tf.tevs[i]);
1284 return (ret < 0) ? ret : tf.ntevs;
1287 /* Collect available variables in this scope */
1288 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1290 struct available_var_finder *af = data;
1291 struct variable_list *vl;
1294 vl = &af->vls[af->nvls - 1];
1296 tag = dwarf_tag(die_mem);
1297 if (tag == DW_TAG_formal_parameter ||
1298 tag == DW_TAG_variable) {
1299 ret = convert_variable_location(die_mem, af->pf.addr,
1300 af->pf.fb_ops, &af->pf.sp_die,
1302 if (ret == 0 || ret == -ERANGE) {
1304 bool externs = !af->child;
1307 strbuf_init(&buf, 64);
1309 if (probe_conf.show_location_range) {
1312 strbuf_addf(&buf, "[INV]\t");
1314 strbuf_addf(&buf, "[VAL]\t");
1316 strbuf_addf(&buf, "[EXT]\t");
1319 ret2 = die_get_varname(die_mem, &buf);
1321 if (!ret2 && probe_conf.show_location_range &&
1323 strbuf_addf(&buf, "\t");
1324 ret2 = die_get_var_range(&af->pf.sp_die,
1328 pr_debug("Add new var: %s\n", buf.buf);
1330 strlist__add(vl->vars,
1331 strbuf_detach(&buf, NULL));
1333 strbuf_release(&buf);
1337 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1338 return DIE_FIND_CB_CONTINUE;
1340 return DIE_FIND_CB_SIBLING;
1343 static bool available_var_finder_overlap(struct available_var_finder *af)
1347 for (i = 0; i < af->nvls; i++) {
1348 if (af->pf.addr == af->vls[i].point.address)
1355 /* Add a found vars into available variables list */
1356 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1358 struct available_var_finder *af =
1359 container_of(pf, struct available_var_finder, pf);
1360 struct perf_probe_point *pp = &pf->pev->point;
1361 struct variable_list *vl;
1366 * For some reason (e.g. different column assigned to same address),
1367 * this callback can be called with the address which already passed.
1370 if (available_var_finder_overlap(af))
1373 /* Check number of tevs */
1374 if (af->nvls == af->max_vls) {
1375 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1378 vl = &af->vls[af->nvls++];
1380 /* Trace point should be converted from subprogram DIE */
1381 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1382 pp->retprobe, pp->function, &vl->point);
1386 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1389 /* Find local variables */
1390 vl->vars = strlist__new(NULL, NULL);
1391 if (vl->vars == NULL)
1394 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1396 /* Find external variables */
1397 if (!probe_conf.show_ext_vars)
1399 /* Don't need to search child DIE for external vars. */
1401 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1404 if (strlist__empty(vl->vars)) {
1405 strlist__delete(vl->vars);
1413 * Find available variables at given probe point
1414 * Return the number of found probe points. Return 0 if there is no
1415 * matched probe point. Return <0 if an error occurs.
1417 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1418 struct perf_probe_event *pev,
1419 struct variable_list **vls)
1421 struct available_var_finder af = {
1422 .pf = {.pev = pev, .callback = add_available_vars},
1424 .max_vls = probe_conf.max_probes};
1427 /* Allocate result vls array */
1428 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1435 ret = debuginfo__find_probes(dbg, &af.pf);
1437 /* Free vlist for error */
1439 zfree(&af.vls[af.nvls].point.symbol);
1440 strlist__delete(af.vls[af.nvls].vars);
1446 return (ret < 0) ? ret : af.nvls;
1449 /* For the kernel module, we need a special code to get a DIE */
1450 static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
1456 GElf_Shdr mem, *shdr;
1459 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1463 /* Get the number of relocations */
1464 n = dwfl_module_relocations(dbg->mod);
1467 /* Search the relocation related .text section */
1468 for (i = 0; i < n; i++) {
1469 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1470 if (strcmp(p, ".text") == 0) {
1471 /* OK, get the section header */
1472 scn = elf_getscn(elf, shndx);
1475 shdr = gelf_getshdr(scn, &mem);
1478 *offs = shdr->sh_addr;
1484 /* Reverse search */
1485 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1486 struct perf_probe_point *ppt)
1488 Dwarf_Die cudie, spdie, indie;
1489 Dwarf_Addr _addr = 0, baseaddr = 0;
1490 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1491 int baseline = 0, lineno = 0, ret = 0;
1493 /* We always need to relocate the address for aranges */
1494 if (debuginfo__get_text_offset(dbg, &baseaddr) == 0)
1497 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1498 pr_warning("Failed to find debug information for address %lx\n",
1504 /* Find a corresponding line (filename and lineno) */
1505 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1506 /* Don't care whether it failed or not */
1508 /* Find a corresponding function (name, baseline and baseaddr) */
1509 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1510 /* Get function entry information */
1511 func = basefunc = dwarf_diename(&spdie);
1513 die_entrypc(&spdie, &baseaddr) != 0 ||
1514 dwarf_decl_line(&spdie, &baseline) != 0) {
1519 fname = dwarf_decl_file(&spdie);
1520 if (addr == (unsigned long)baseaddr) {
1521 /* Function entry - Relative line number is 0 */
1526 /* Track down the inline functions step by step */
1527 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1529 /* There is an inline function */
1530 if (die_entrypc(&indie, &_addr) == 0 &&
1533 * addr is at an inline function entry.
1534 * In this case, lineno should be the call-site
1535 * line number. (overwrite lineinfo)
1537 lineno = die_get_call_lineno(&indie);
1538 fname = die_get_call_file(&indie);
1542 * addr is in an inline function body.
1543 * Since lineno points one of the lines
1544 * of the inline function, baseline should
1545 * be the entry line of the inline function.
1547 tmp = dwarf_diename(&indie);
1549 dwarf_decl_line(&indie, &baseline) != 0)
1555 /* Verify the lineno and baseline are in a same file */
1556 tmp = dwarf_decl_file(&spdie);
1557 if (!tmp || strcmp(tmp, fname) != 0)
1562 /* Make a relative line number or an offset */
1564 ppt->line = lineno - baseline;
1565 else if (basefunc) {
1566 ppt->offset = addr - (unsigned long)baseaddr;
1570 /* Duplicate strings */
1572 ppt->function = strdup(func);
1573 if (ppt->function == NULL) {
1579 ppt->file = strdup(fname);
1580 if (ppt->file == NULL) {
1581 zfree(&ppt->function);
1587 if (ret == 0 && (fname || func))
1588 ret = 1; /* Found a point */
1592 /* Add a line and store the src path */
1593 static int line_range_add_line(const char *src, unsigned int lineno,
1594 struct line_range *lr)
1596 /* Copy source path */
1598 lr->path = strdup(src);
1599 if (lr->path == NULL)
1602 return intlist__add(lr->line_list, lineno);
1605 static int line_range_walk_cb(const char *fname, int lineno,
1606 Dwarf_Addr addr __maybe_unused,
1609 struct line_finder *lf = data;
1612 if ((strtailcmp(fname, lf->fname) != 0) ||
1613 (lf->lno_s > lineno || lf->lno_e < lineno))
1616 err = line_range_add_line(fname, lineno, lf->lr);
1617 if (err < 0 && err != -EEXIST)
1623 /* Find line range from its line number */
1624 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1628 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1632 if (!intlist__empty(lf->lr->line_list))
1633 ret = lf->found = 1;
1635 ret = 0; /* Lines are not found */
1637 zfree(&lf->lr->path);
1642 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1644 int ret = find_line_range_by_line(in_die, data);
1647 * We have to check all instances of inlined function, because
1648 * some execution paths can be optimized out depends on the
1649 * function argument of instances. However, if an error occurs,
1650 * it should be handled by the caller.
1652 return ret < 0 ? ret : 0;
1655 /* Search function definition from function name */
1656 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1658 struct dwarf_callback_param *param = data;
1659 struct line_finder *lf = param->data;
1660 struct line_range *lr = lf->lr;
1662 /* Check declared file */
1663 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1666 if (die_is_func_def(sp_die) &&
1667 die_match_name(sp_die, lr->function)) {
1668 lf->fname = dwarf_decl_file(sp_die);
1669 dwarf_decl_line(sp_die, &lr->offset);
1670 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1671 lf->lno_s = lr->offset + lr->start;
1672 if (lf->lno_s < 0) /* Overflow */
1673 lf->lno_s = INT_MAX;
1674 lf->lno_e = lr->offset + lr->end;
1675 if (lf->lno_e < 0) /* Overflow */
1676 lf->lno_e = INT_MAX;
1677 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1678 lr->start = lf->lno_s;
1679 lr->end = lf->lno_e;
1680 if (!die_is_func_instance(sp_die))
1681 param->retval = die_walk_instances(sp_die,
1682 line_range_inline_cb, lf);
1684 param->retval = find_line_range_by_line(sp_die, lf);
1685 return DWARF_CB_ABORT;
1690 static int find_line_range_by_func(struct line_finder *lf)
1692 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1693 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1694 return param.retval;
1697 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1699 struct line_finder lf = {.lr = lr, .found = 0};
1701 Dwarf_Off off = 0, noff;
1704 const char *comp_dir;
1706 /* Fastpath: lookup by function name from .debug_pubnames section */
1708 struct pubname_callback_param pubname_param = {
1709 .function = lr->function, .file = lr->file,
1710 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1711 struct dwarf_callback_param line_range_param = {
1712 .data = (void *)&lf, .retval = 0};
1714 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1716 if (pubname_param.found) {
1717 line_range_search_cb(&lf.sp_die, &line_range_param);
1723 /* Loop on CUs (Compilation Unit) */
1724 while (!lf.found && ret >= 0) {
1725 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1726 NULL, NULL, NULL) != 0)
1729 /* Get the DIE(Debugging Information Entry) of this CU */
1730 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1734 /* Check if target file is included. */
1736 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1740 if (!lr->file || lf.fname) {
1742 ret = find_line_range_by_func(&lf);
1744 lf.lno_s = lr->start;
1746 ret = find_line_range_by_line(NULL, &lf);
1753 /* Store comp_dir */
1755 comp_dir = cu_get_comp_dir(&lf.cu_die);
1757 lr->comp_dir = strdup(comp_dir);
1763 pr_debug("path: %s\n", lr->path);
1764 return (ret < 0) ? ret : lf.found;
1768 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1769 * and chop off leading directories that do not exist. Result is passed back as
1770 * a newly allocated path on success.
1771 * Return 0 if file was found and readable, -errno otherwise.
1773 int get_real_path(const char *raw_path, const char *comp_dir,
1776 const char *prefix = symbol_conf.source_prefix;
1779 if (raw_path[0] != '/' && comp_dir)
1780 /* If not an absolute path, try to use comp_dir */
1783 if (access(raw_path, R_OK) == 0) {
1784 *new_path = strdup(raw_path);
1785 return *new_path ? 0 : -ENOMEM;
1791 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1796 sprintf(*new_path, "%s/%s", prefix, raw_path);
1798 if (access(*new_path, R_OK) == 0)
1801 if (!symbol_conf.source_prefix) {
1802 /* In case of searching comp_dir, don't retry */
1812 raw_path = strchr(++raw_path, '/');