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__NOT_FOUND,
116 struct debuginfo *debuginfo__new(const char *path)
118 enum dso_binary_type *type;
119 char buf[PATH_MAX], nil = '\0';
121 struct debuginfo *dinfo = NULL;
123 /* Try to open distro debuginfo files */
124 dso = dso__new(path);
128 for (type = distro_dwarf_types;
129 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
131 if (dso__read_binary_type_filename(dso, *type, &nil,
134 dinfo = __debuginfo__new(buf);
139 /* if failed to open all distro debuginfo, open given binary */
140 return dinfo ? : __debuginfo__new(path);
143 void debuginfo__delete(struct debuginfo *dbg)
153 * Probe finder related functions
156 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
158 struct probe_trace_arg_ref *ref;
159 ref = zalloc(sizeof(struct probe_trace_arg_ref));
166 * Convert a location into trace_arg.
167 * If tvar == NULL, this just checks variable can be converted.
168 * If fentry == true and vr_die is a parameter, do huristic search
169 * for the location fuzzed by function entry mcount.
171 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
172 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
173 struct probe_trace_arg *tvar)
175 Dwarf_Attribute attr;
185 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
188 /* TODO: handle more than 1 exprs */
189 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
190 return -EINVAL; /* Broken DIE ? */
191 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
192 ret = dwarf_entrypc(sp_die, &tmp);
196 if (probe_conf.show_location_range &&
197 (dwarf_tag(vr_die) == DW_TAG_variable)) {
199 } else if (addr != tmp ||
200 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
204 ret = dwarf_highpc(sp_die, &tmp);
208 * This is fuzzed by fentry mcount. We try to find the
209 * parameter location at the earliest address.
211 for (addr += 1; addr <= tmp; addr++) {
212 if (dwarf_getlocation_addr(&attr, addr, &op,
220 /* TODO: Support const_value */
223 if (op->atom == DW_OP_addr) {
227 /* Static variables on memory (not stack), make @varname */
228 ret = strlen(dwarf_diename(vr_die));
229 tvar->value = zalloc(ret + 2);
230 if (tvar->value == NULL)
232 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
233 tvar->ref = alloc_trace_arg_ref((long)offs);
234 if (tvar->ref == NULL)
239 /* If this is based on frame buffer, set the offset */
240 if (op->atom == DW_OP_fbreg) {
248 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
249 regn = op->atom - DW_OP_breg0;
252 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
253 regn = op->atom - DW_OP_reg0;
254 } else if (op->atom == DW_OP_bregx) {
258 } else if (op->atom == DW_OP_regx) {
261 pr_debug("DW_OP %x is not supported.\n", op->atom);
268 regs = get_arch_regstr(regn);
270 /* This should be a bug in DWARF or this tool */
271 pr_warning("Mapping for the register number %u "
272 "missing on this architecture.\n", regn);
276 tvar->value = strdup(regs);
277 if (tvar->value == NULL)
281 tvar->ref = alloc_trace_arg_ref((long)offs);
282 if (tvar->ref == NULL)
288 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
290 static int convert_variable_type(Dwarf_Die *vr_die,
291 struct probe_trace_arg *tvar,
294 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
297 char sbuf[STRERR_BUFSIZE];
298 int bsize, boffs, total;
302 /* TODO: check all types */
303 if (cast && strcmp(cast, "string") != 0 &&
304 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
305 /* Non string type is OK */
306 /* and respect signedness cast */
307 tvar->type = strdup(cast);
308 return (tvar->type == NULL) ? -ENOMEM : 0;
311 bsize = dwarf_bitsize(vr_die);
313 /* This is a bitfield */
314 boffs = dwarf_bitoffset(vr_die);
315 total = dwarf_bytesize(vr_die);
316 if (boffs < 0 || total < 0)
318 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
319 BYTES_TO_BITS(total));
323 if (die_get_real_type(vr_die, &type) == NULL) {
324 pr_warning("Failed to get a type information of %s.\n",
325 dwarf_diename(vr_die));
329 pr_debug("%s type is %s.\n",
330 dwarf_diename(vr_die), dwarf_diename(&type));
332 if (cast && strcmp(cast, "string") == 0) { /* String type */
333 ret = dwarf_tag(&type);
334 if (ret != DW_TAG_pointer_type &&
335 ret != DW_TAG_array_type) {
336 pr_warning("Failed to cast into string: "
337 "%s(%s) is not a pointer nor array.\n",
338 dwarf_diename(vr_die), dwarf_diename(&type));
341 if (die_get_real_type(&type, &type) == NULL) {
342 pr_warning("Failed to get a type"
346 if (ret == DW_TAG_pointer_type) {
348 ref_ptr = &(*ref_ptr)->next;
349 /* Add new reference with offset +0 */
350 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
351 if (*ref_ptr == NULL) {
352 pr_warning("Out of memory error\n");
356 if (!die_compare_name(&type, "char") &&
357 !die_compare_name(&type, "unsigned char")) {
358 pr_warning("Failed to cast into string: "
359 "%s is not (unsigned) char *.\n",
360 dwarf_diename(vr_die));
363 tvar->type = strdup(cast);
364 return (tvar->type == NULL) ? -ENOMEM : 0;
367 if (cast && (strcmp(cast, "u") == 0))
369 else if (cast && (strcmp(cast, "s") == 0))
372 sign = die_is_signed_type(&type) ? 's' : 'u';
374 ret = dwarf_bytesize(&type);
376 /* No size ... try to use default type */
378 ret = BYTES_TO_BITS(ret);
380 /* Check the bitwidth */
381 if (ret > MAX_BASIC_TYPE_BITS) {
382 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
383 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
384 ret = MAX_BASIC_TYPE_BITS;
386 ret = snprintf(buf, 16, "%c%d", sign, ret);
389 if (ret < 0 || ret >= 16) {
392 pr_warning("Failed to convert variable type: %s\n",
393 str_error_r(-ret, sbuf, sizeof(sbuf)));
396 tvar->type = strdup(buf);
397 if (tvar->type == NULL)
402 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
403 struct perf_probe_arg_field *field,
404 struct probe_trace_arg_ref **ref_ptr,
407 struct probe_trace_arg_ref *ref = *ref_ptr;
412 pr_debug("converting %s in %s\n", field->name, varname);
413 if (die_get_real_type(vr_die, &type) == NULL) {
414 pr_warning("Failed to get the type of %s.\n", varname);
417 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
418 tag = dwarf_tag(&type);
420 if (field->name[0] == '[' &&
421 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
423 /* Save original type for next field */
424 memcpy(die_mem, &type, sizeof(*die_mem));
425 /* Get the type of this array */
426 if (die_get_real_type(&type, &type) == NULL) {
427 pr_warning("Failed to get the type of %s.\n", varname);
430 pr_debug2("Array real type: (%x)\n",
431 (unsigned)dwarf_dieoffset(&type));
432 if (tag == DW_TAG_pointer_type) {
433 ref = zalloc(sizeof(struct probe_trace_arg_ref));
437 (*ref_ptr)->next = ref;
441 ref->offset += dwarf_bytesize(&type) * field->index;
443 /* Save vr_die for converting types */
444 memcpy(die_mem, vr_die, sizeof(*die_mem));
446 } else if (tag == DW_TAG_pointer_type) {
447 /* Check the pointer and dereference */
449 pr_err("Semantic error: %s must be referred by '->'\n",
453 /* Get the type pointed by this pointer */
454 if (die_get_real_type(&type, &type) == NULL) {
455 pr_warning("Failed to get the type of %s.\n", varname);
458 /* Verify it is a data structure */
459 tag = dwarf_tag(&type);
460 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
461 pr_warning("%s is not a data structure nor an union.\n",
466 ref = zalloc(sizeof(struct probe_trace_arg_ref));
470 (*ref_ptr)->next = ref;
474 /* Verify it is a data structure */
475 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
476 pr_warning("%s is not a data structure nor an union.\n",
480 if (field->name[0] == '[') {
481 pr_err("Semantic error: %s is not a pointer"
482 " nor array.\n", varname);
485 /* While prcessing unnamed field, we don't care about this */
486 if (field->ref && dwarf_diename(vr_die)) {
487 pr_err("Semantic error: %s must be referred by '.'\n",
492 pr_warning("Structure on a register is not "
498 if (die_find_member(&type, field->name, die_mem) == NULL) {
499 pr_warning("%s(type:%s) has no member %s.\n", varname,
500 dwarf_diename(&type), field->name);
504 /* Get the offset of the field */
505 if (tag == DW_TAG_union_type) {
508 ret = die_get_data_member_location(die_mem, &offs);
510 pr_warning("Failed to get the offset of %s.\n",
515 ref->offset += (long)offs;
517 /* If this member is unnamed, we need to reuse this field */
518 if (!dwarf_diename(die_mem))
519 return convert_variable_fields(die_mem, varname, field,
523 /* Converting next field */
525 return convert_variable_fields(die_mem, field->name,
526 field->next, &ref, die_mem);
531 /* Show a variables in kprobe event format */
532 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
537 pr_debug("Converting variable %s into trace event.\n",
538 dwarf_diename(vr_die));
540 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
541 &pf->sp_die, pf->tvar);
542 if (ret == -ENOENT || ret == -EINVAL) {
543 pr_err("Failed to find the location of the '%s' variable at this address.\n"
544 " Perhaps it has been optimized out.\n"
545 " Use -V with the --range option to show '%s' location range.\n",
546 pf->pvar->var, pf->pvar->var);
547 } else if (ret == -ENOTSUP)
548 pr_err("Sorry, we don't support this variable location yet.\n");
549 else if (ret == 0 && pf->pvar->field) {
550 ret = convert_variable_fields(vr_die, pf->pvar->var,
551 pf->pvar->field, &pf->tvar->ref,
556 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
557 /* *expr will be cached in libdw. Don't free it. */
561 /* Find a variable in a scope DIE */
562 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
568 /* Copy raw parameters */
569 if (!is_c_varname(pf->pvar->var))
570 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
573 pf->tvar->name = strdup(pf->pvar->name);
575 buf = synthesize_perf_probe_arg(pf->pvar);
578 ptr = strchr(buf, ':'); /* Change type separator to _ */
581 pf->tvar->name = buf;
583 if (pf->tvar->name == NULL)
586 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
587 /* Search child die for local variables and parameters. */
588 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
589 /* Search again in global variables */
590 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
592 pr_warning("Failed to find '%s' in this function.\n",
598 ret = convert_variable(&vr_die, pf);
603 /* Convert subprogram DIE to trace point */
604 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
605 Dwarf_Addr paddr, bool retprobe,
606 const char *function,
607 struct probe_trace_point *tp)
609 Dwarf_Addr eaddr, highaddr;
613 /* Verify the address is correct */
614 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
615 pr_warning("Failed to get entry address of %s\n",
616 dwarf_diename(sp_die));
619 if (dwarf_highpc(sp_die, &highaddr) != 0) {
620 pr_warning("Failed to get end address of %s\n",
621 dwarf_diename(sp_die));
624 if (paddr > highaddr) {
625 pr_warning("Offset specified is greater than size of %s\n",
626 dwarf_diename(sp_die));
630 symbol = dwarf_diename(sp_die);
632 /* Try to get the symbol name from symtab */
633 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
635 pr_warning("Failed to find symbol at 0x%lx\n",
636 (unsigned long)paddr);
639 eaddr = sym.st_value;
641 tp->offset = (unsigned long)(paddr - eaddr);
642 tp->address = (unsigned long)paddr;
643 tp->symbol = strdup(symbol);
647 /* Return probe must be on the head of a subprogram */
649 if (eaddr != paddr) {
650 pr_warning("Failed to find \"%s%%return\",\n"
651 " because %s is an inlined function and"
652 " has no return point.\n", function,
662 /* Call probe_finder callback with scope DIE */
663 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
665 Dwarf_Attribute fb_attr;
666 Dwarf_Frame *frame = NULL;
671 pr_err("Caller must pass a scope DIE. Program error.\n");
675 /* If not a real subprogram, find a real one */
676 if (!die_is_func_def(sc_die)) {
677 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
678 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
679 pr_warning("Ignoring tail call from %s\n",
680 dwarf_diename(&pf->sp_die));
683 pr_warning("Failed to find probe point in any "
689 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
691 /* Get the frame base attribute/ops from subprogram */
692 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
693 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
694 if (ret <= 0 || nops == 0) {
696 #if _ELFUTILS_PREREQ(0, 142)
697 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
698 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
699 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
700 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
701 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
702 pr_warning("Failed to get call frame on 0x%jx\n",
703 (uintmax_t)pf->addr);
710 /* Call finder's callback handler */
711 ret = pf->callback(sc_die, pf);
713 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
720 struct find_scope_param {
721 const char *function;
729 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
731 struct find_scope_param *fsp = data;
735 /* Skip if declared file name does not match */
737 file = dwarf_decl_file(fn_die);
738 if (!file || strcmp(fsp->file, file) != 0)
741 /* If the function name is given, that's what user expects */
743 if (die_match_name(fn_die, fsp->function)) {
744 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
749 /* With the line number, find the nearest declared DIE */
750 dwarf_decl_line(fn_die, &lno);
751 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
752 /* Keep a candidate and continue */
753 fsp->diff = fsp->line - lno;
754 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
761 /* Find an appropriate scope fits to given conditions */
762 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
764 struct find_scope_param fsp = {
765 .function = pf->pev->point.function,
773 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
775 return fsp.found ? die_mem : NULL;
778 static int probe_point_line_walker(const char *fname, int lineno,
779 Dwarf_Addr addr, void *data)
781 struct probe_finder *pf = data;
782 Dwarf_Die *sc_die, die_mem;
785 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
789 sc_die = find_best_scope(pf, &die_mem);
791 pr_warning("Failed to find scope of probe point.\n");
795 ret = call_probe_finder(sc_die, pf);
797 /* Continue if no error, because the line will be in inline function */
798 return ret < 0 ? ret : 0;
801 /* Find probe point from its line number */
802 static int find_probe_point_by_line(struct probe_finder *pf)
804 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
807 /* Find lines which match lazy pattern */
808 static int find_lazy_match_lines(struct intlist *list,
809 const char *fname, const char *pat)
815 int count = 0, linenum = 1;
816 char sbuf[STRERR_BUFSIZE];
818 fp = fopen(fname, "r");
820 pr_warning("Failed to open %s: %s\n", fname,
821 str_error_r(errno, sbuf, sizeof(sbuf)));
825 while ((len = getline(&line, &line_len, fp)) > 0) {
827 if (line[len - 1] == '\n')
828 line[len - 1] = '\0';
830 if (strlazymatch(line, pat)) {
831 intlist__add(list, linenum);
843 pr_debug("No matched lines found in %s.\n", fname);
847 static int probe_point_lazy_walker(const char *fname, int lineno,
848 Dwarf_Addr addr, void *data)
850 struct probe_finder *pf = data;
851 Dwarf_Die *sc_die, die_mem;
854 if (!intlist__has_entry(pf->lcache, lineno) ||
855 strtailcmp(fname, pf->fname) != 0)
858 pr_debug("Probe line found: line:%d addr:0x%llx\n",
859 lineno, (unsigned long long)addr);
862 sc_die = find_best_scope(pf, &die_mem);
864 pr_warning("Failed to find scope of probe point.\n");
868 ret = call_probe_finder(sc_die, pf);
871 * Continue if no error, because the lazy pattern will match
874 return ret < 0 ? ret : 0;
877 /* Find probe points from lazy pattern */
878 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
883 if (intlist__empty(pf->lcache)) {
884 const char *comp_dir;
886 comp_dir = cu_get_comp_dir(&pf->cu_die);
887 ret = get_real_path(pf->fname, comp_dir, &fpath);
889 pr_warning("Failed to find source file path.\n");
893 /* Matching lazy line pattern */
894 ret = find_lazy_match_lines(pf->lcache, fpath,
895 pf->pev->point.lazy_line);
901 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
904 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
906 struct probe_finder *pf = data;
907 struct perf_probe_point *pp = &pf->pev->point;
912 ret = find_probe_point_lazy(in_die, pf);
914 /* Get probe address */
915 if (dwarf_entrypc(in_die, &addr) != 0) {
916 pr_warning("Failed to get entry address of %s.\n",
917 dwarf_diename(in_die));
921 pf->addr += pp->offset;
922 pr_debug("found inline addr: 0x%jx\n",
923 (uintmax_t)pf->addr);
925 ret = call_probe_finder(in_die, pf);
931 /* Callback parameter with return value for libdw */
932 struct dwarf_callback_param {
937 /* Search function from function name */
938 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
940 struct dwarf_callback_param *param = data;
941 struct probe_finder *pf = param->data;
942 struct perf_probe_point *pp = &pf->pev->point;
944 /* Check tag and diename */
945 if (!die_is_func_def(sp_die) ||
946 !die_match_name(sp_die, pp->function))
949 /* Check declared file */
950 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
953 pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
954 pf->fname = dwarf_decl_file(sp_die);
955 if (pp->line) { /* Function relative line */
956 dwarf_decl_line(sp_die, &pf->lno);
958 param->retval = find_probe_point_by_line(pf);
959 } else if (die_is_func_instance(sp_die)) {
960 /* Instances always have the entry address */
961 dwarf_entrypc(sp_die, &pf->addr);
964 param->retval = find_probe_point_lazy(sp_die, pf);
966 pf->addr += pp->offset;
967 /* TODO: Check the address in this function */
968 param->retval = call_probe_finder(sp_die, pf);
970 } else if (!probe_conf.no_inlines) {
971 /* Inlined function: search instances */
972 param->retval = die_walk_instances(sp_die,
973 probe_point_inline_cb, (void *)pf);
974 /* This could be a non-existed inline definition */
975 if (param->retval == -ENOENT && strisglob(pp->function))
979 /* We need to find other candidates */
980 if (strisglob(pp->function) && param->retval >= 0) {
981 param->retval = 0; /* We have to clear the result */
985 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
988 static int find_probe_point_by_func(struct probe_finder *pf)
990 struct dwarf_callback_param _param = {.data = (void *)pf,
992 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
993 return _param.retval;
996 struct pubname_callback_param {
1004 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1006 struct pubname_callback_param *param = data;
1008 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1009 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1012 if (die_match_name(param->sp_die, param->function)) {
1013 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1017 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1021 return DWARF_CB_ABORT;
1028 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1029 struct probe_finder *pf)
1031 struct perf_probe_point *pp = &pf->pev->point;
1032 Dwarf_Off off, noff;
1038 pf->lcache = intlist__new(NULL);
1042 /* Fastpath: lookup by function name from .debug_pubnames section */
1043 if (pp->function && !strisglob(pp->function)) {
1044 struct pubname_callback_param pubname_param = {
1045 .function = pp->function,
1047 .cu_die = &pf->cu_die,
1048 .sp_die = &pf->sp_die,
1051 struct dwarf_callback_param probe_param = {
1055 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1057 if (pubname_param.found) {
1058 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1064 /* Loop on CUs (Compilation Unit) */
1065 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1066 /* Get the DIE(Debugging Information Entry) of this CU */
1067 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1071 /* Check if target file is included. */
1073 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1077 if (!pp->file || pf->fname) {
1079 ret = find_probe_point_by_func(pf);
1080 else if (pp->lazy_line)
1081 ret = find_probe_point_lazy(&pf->cu_die, pf);
1084 ret = find_probe_point_by_line(pf);
1093 intlist__delete(pf->lcache);
1099 /* Find probe points from debuginfo */
1100 static int debuginfo__find_probes(struct debuginfo *dbg,
1101 struct probe_finder *pf)
1105 #if _ELFUTILS_PREREQ(0, 142)
1110 if (pf->cfi_eh || pf->cfi_dbg)
1111 return debuginfo__find_probe_location(dbg, pf);
1113 /* Get the call frame information from this dwarf */
1114 elf = dwarf_getelf(dbg->dbg);
1118 if (gelf_getehdr(elf, &ehdr) == NULL)
1121 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1122 shdr.sh_type == SHT_PROGBITS)
1123 pf->cfi_eh = dwarf_getcfi_elf(elf);
1125 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1128 ret = debuginfo__find_probe_location(dbg, pf);
1132 struct local_vars_finder {
1133 struct probe_finder *pf;
1134 struct perf_probe_arg *args;
1141 /* Collect available variables in this scope */
1142 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1144 struct local_vars_finder *vf = data;
1145 struct probe_finder *pf = vf->pf;
1148 tag = dwarf_tag(die_mem);
1149 if (tag == DW_TAG_formal_parameter ||
1150 (tag == DW_TAG_variable && vf->vars)) {
1151 if (convert_variable_location(die_mem, vf->pf->addr,
1152 vf->pf->fb_ops, &pf->sp_die,
1154 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1155 if (vf->args[vf->nargs].var == NULL) {
1157 return DIE_FIND_CB_END;
1159 pr_debug(" %s", vf->args[vf->nargs].var);
1164 if (dwarf_haspc(die_mem, vf->pf->addr))
1165 return DIE_FIND_CB_CONTINUE;
1167 return DIE_FIND_CB_SIBLING;
1170 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1171 struct perf_probe_arg *args)
1176 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1177 .max_args = MAX_PROBE_ARGS, .ret = 0};
1179 for (i = 0; i < pf->pev->nargs; i++) {
1180 /* var never be NULL */
1181 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1183 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1184 /* Copy normal argument */
1185 args[n] = pf->pev->args[i];
1189 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1191 /* Special local variables */
1192 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1194 pr_debug(" (%d)\n", vf.nargs - n);
1202 /* Add a found probe point into trace event list */
1203 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1205 struct trace_event_finder *tf =
1206 container_of(pf, struct trace_event_finder, pf);
1207 struct perf_probe_point *pp = &pf->pev->point;
1208 struct probe_trace_event *tev;
1209 struct perf_probe_arg *args = NULL;
1212 /* Check number of tevs */
1213 if (tf->ntevs == tf->max_tevs) {
1214 pr_warning("Too many( > %d) probe point found.\n",
1218 tev = &tf->tevs[tf->ntevs++];
1220 /* Trace point should be converted from subprogram DIE */
1221 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1222 pp->retprobe, pp->function, &tev->point);
1226 tev->point.realname = strdup(dwarf_diename(sc_die));
1227 if (!tev->point.realname) {
1232 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1235 /* Expand special probe argument if exist */
1236 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1242 ret = expand_probe_args(sc_die, pf, args);
1247 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1248 if (tev->args == NULL) {
1253 /* Find each argument */
1254 for (i = 0; i < tev->nargs; i++) {
1255 pf->pvar = &args[i];
1256 pf->tvar = &tev->args[i];
1257 /* Variable should be found from scope DIE */
1258 ret = find_variable(sc_die, pf);
1265 clear_probe_trace_event(tev);
1272 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1273 int debuginfo__find_trace_events(struct debuginfo *dbg,
1274 struct perf_probe_event *pev,
1275 struct probe_trace_event **tevs)
1277 struct trace_event_finder tf = {
1278 .pf = {.pev = pev, .callback = add_probe_trace_event},
1279 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1282 /* Allocate result tevs array */
1283 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1290 ret = debuginfo__find_probes(dbg, &tf.pf);
1292 for (i = 0; i < tf.ntevs; i++)
1293 clear_probe_trace_event(&tf.tevs[i]);
1298 return (ret < 0) ? ret : tf.ntevs;
1301 /* Collect available variables in this scope */
1302 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1304 struct available_var_finder *af = data;
1305 struct variable_list *vl;
1306 struct strbuf buf = STRBUF_INIT;
1309 vl = &af->vls[af->nvls - 1];
1311 tag = dwarf_tag(die_mem);
1312 if (tag == DW_TAG_formal_parameter ||
1313 tag == DW_TAG_variable) {
1314 ret = convert_variable_location(die_mem, af->pf.addr,
1315 af->pf.fb_ops, &af->pf.sp_die,
1317 if (ret == 0 || ret == -ERANGE) {
1319 bool externs = !af->child;
1321 if (strbuf_init(&buf, 64) < 0)
1324 if (probe_conf.show_location_range) {
1326 ret2 = strbuf_add(&buf,
1327 ret ? "[INV]\t" : "[VAL]\t", 6);
1329 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1334 ret2 = die_get_varname(die_mem, &buf);
1336 if (!ret2 && probe_conf.show_location_range &&
1338 if (strbuf_addch(&buf, '\t') < 0)
1340 ret2 = die_get_var_range(&af->pf.sp_die,
1344 pr_debug("Add new var: %s\n", buf.buf);
1346 strlist__add(vl->vars,
1347 strbuf_detach(&buf, NULL));
1349 strbuf_release(&buf);
1353 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1354 return DIE_FIND_CB_CONTINUE;
1356 return DIE_FIND_CB_SIBLING;
1358 strbuf_release(&buf);
1359 pr_debug("Error in strbuf\n");
1360 return DIE_FIND_CB_END;
1363 /* Add a found vars into available variables list */
1364 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1366 struct available_var_finder *af =
1367 container_of(pf, struct available_var_finder, pf);
1368 struct perf_probe_point *pp = &pf->pev->point;
1369 struct variable_list *vl;
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;
1496 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1497 if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
1502 pr_warning("Failed to find debug information for address %lx\n",
1508 /* Find a corresponding line (filename and lineno) */
1509 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1510 /* Don't care whether it failed or not */
1512 /* Find a corresponding function (name, baseline and baseaddr) */
1513 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1514 /* Get function entry information */
1515 func = basefunc = dwarf_diename(&spdie);
1517 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1518 dwarf_decl_line(&spdie, &baseline) != 0) {
1523 fname = dwarf_decl_file(&spdie);
1524 if (addr == (unsigned long)baseaddr) {
1525 /* Function entry - Relative line number is 0 */
1530 /* Track down the inline functions step by step */
1531 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1533 /* There is an inline function */
1534 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1537 * addr is at an inline function entry.
1538 * In this case, lineno should be the call-site
1539 * line number. (overwrite lineinfo)
1541 lineno = die_get_call_lineno(&indie);
1542 fname = die_get_call_file(&indie);
1546 * addr is in an inline function body.
1547 * Since lineno points one of the lines
1548 * of the inline function, baseline should
1549 * be the entry line of the inline function.
1551 tmp = dwarf_diename(&indie);
1553 dwarf_decl_line(&indie, &baseline) != 0)
1559 /* Verify the lineno and baseline are in a same file */
1560 tmp = dwarf_decl_file(&spdie);
1561 if (!tmp || strcmp(tmp, fname) != 0)
1566 /* Make a relative line number or an offset */
1568 ppt->line = lineno - baseline;
1569 else if (basefunc) {
1570 ppt->offset = addr - (unsigned long)baseaddr;
1574 /* Duplicate strings */
1576 ppt->function = strdup(func);
1577 if (ppt->function == NULL) {
1583 ppt->file = strdup(fname);
1584 if (ppt->file == NULL) {
1585 zfree(&ppt->function);
1591 if (ret == 0 && (fname || func))
1592 ret = 1; /* Found a point */
1596 /* Add a line and store the src path */
1597 static int line_range_add_line(const char *src, unsigned int lineno,
1598 struct line_range *lr)
1600 /* Copy source path */
1602 lr->path = strdup(src);
1603 if (lr->path == NULL)
1606 return intlist__add(lr->line_list, lineno);
1609 static int line_range_walk_cb(const char *fname, int lineno,
1610 Dwarf_Addr addr __maybe_unused,
1613 struct line_finder *lf = data;
1616 if ((strtailcmp(fname, lf->fname) != 0) ||
1617 (lf->lno_s > lineno || lf->lno_e < lineno))
1620 err = line_range_add_line(fname, lineno, lf->lr);
1621 if (err < 0 && err != -EEXIST)
1627 /* Find line range from its line number */
1628 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1632 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1636 if (!intlist__empty(lf->lr->line_list))
1637 ret = lf->found = 1;
1639 ret = 0; /* Lines are not found */
1641 zfree(&lf->lr->path);
1646 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1648 int ret = find_line_range_by_line(in_die, data);
1651 * We have to check all instances of inlined function, because
1652 * some execution paths can be optimized out depends on the
1653 * function argument of instances. However, if an error occurs,
1654 * it should be handled by the caller.
1656 return ret < 0 ? ret : 0;
1659 /* Search function definition from function name */
1660 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1662 struct dwarf_callback_param *param = data;
1663 struct line_finder *lf = param->data;
1664 struct line_range *lr = lf->lr;
1666 /* Check declared file */
1667 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1670 if (die_is_func_def(sp_die) &&
1671 die_match_name(sp_die, lr->function)) {
1672 lf->fname = dwarf_decl_file(sp_die);
1673 dwarf_decl_line(sp_die, &lr->offset);
1674 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1675 lf->lno_s = lr->offset + lr->start;
1676 if (lf->lno_s < 0) /* Overflow */
1677 lf->lno_s = INT_MAX;
1678 lf->lno_e = lr->offset + lr->end;
1679 if (lf->lno_e < 0) /* Overflow */
1680 lf->lno_e = INT_MAX;
1681 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1682 lr->start = lf->lno_s;
1683 lr->end = lf->lno_e;
1684 if (!die_is_func_instance(sp_die))
1685 param->retval = die_walk_instances(sp_die,
1686 line_range_inline_cb, lf);
1688 param->retval = find_line_range_by_line(sp_die, lf);
1689 return DWARF_CB_ABORT;
1694 static int find_line_range_by_func(struct line_finder *lf)
1696 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1697 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1698 return param.retval;
1701 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1703 struct line_finder lf = {.lr = lr, .found = 0};
1705 Dwarf_Off off = 0, noff;
1708 const char *comp_dir;
1710 /* Fastpath: lookup by function name from .debug_pubnames section */
1712 struct pubname_callback_param pubname_param = {
1713 .function = lr->function, .file = lr->file,
1714 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1715 struct dwarf_callback_param line_range_param = {
1716 .data = (void *)&lf, .retval = 0};
1718 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1720 if (pubname_param.found) {
1721 line_range_search_cb(&lf.sp_die, &line_range_param);
1727 /* Loop on CUs (Compilation Unit) */
1728 while (!lf.found && ret >= 0) {
1729 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1730 NULL, NULL, NULL) != 0)
1733 /* Get the DIE(Debugging Information Entry) of this CU */
1734 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1738 /* Check if target file is included. */
1740 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1744 if (!lr->file || lf.fname) {
1746 ret = find_line_range_by_func(&lf);
1748 lf.lno_s = lr->start;
1750 ret = find_line_range_by_line(NULL, &lf);
1757 /* Store comp_dir */
1759 comp_dir = cu_get_comp_dir(&lf.cu_die);
1761 lr->comp_dir = strdup(comp_dir);
1767 pr_debug("path: %s\n", lr->path);
1768 return (ret < 0) ? ret : lf.found;
1772 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1773 * and chop off leading directories that do not exist. Result is passed back as
1774 * a newly allocated path on success.
1775 * Return 0 if file was found and readable, -errno otherwise.
1777 int get_real_path(const char *raw_path, const char *comp_dir,
1780 const char *prefix = symbol_conf.source_prefix;
1783 if (raw_path[0] != '/' && comp_dir)
1784 /* If not an absolute path, try to use comp_dir */
1787 if (access(raw_path, R_OK) == 0) {
1788 *new_path = strdup(raw_path);
1789 return *new_path ? 0 : -ENOMEM;
1795 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1800 sprintf(*new_path, "%s/%s", prefix, raw_path);
1802 if (access(*new_path, R_OK) == 0)
1805 if (!symbol_conf.source_prefix) {
1806 /* In case of searching comp_dir, don't retry */
1816 raw_path = strchr(++raw_path, '/');