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"
42 #include "probe-file.h"
44 /* Kprobe tracer basic type is up to u64 */
45 #define MAX_BASIC_TYPE_BITS 64
47 /* Dwarf FL wrappers */
48 static char *debuginfo_path; /* Currently dummy */
50 static const Dwfl_Callbacks offline_callbacks = {
51 .find_debuginfo = dwfl_standard_find_debuginfo,
52 .debuginfo_path = &debuginfo_path,
54 .section_address = dwfl_offline_section_address,
56 /* We use this table for core files too. */
57 .find_elf = dwfl_build_id_find_elf,
60 /* Get a Dwarf from offline image */
61 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
66 fd = open(path, O_RDONLY);
70 dbg->dwfl = dwfl_begin(&offline_callbacks);
74 dwfl_report_begin(dbg->dwfl);
75 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
79 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
83 dwfl_report_end(dbg->dwfl, NULL, NULL);
91 memset(dbg, 0, sizeof(*dbg));
96 static struct debuginfo *__debuginfo__new(const char *path)
98 struct debuginfo *dbg = zalloc(sizeof(*dbg));
102 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
105 pr_debug("Open Debuginfo file: %s\n", path);
109 enum dso_binary_type distro_dwarf_types[] = {
110 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
111 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
112 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
113 DSO_BINARY_TYPE__BUILDID_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 unsigned int machine,
175 struct probe_trace_arg *tvar)
177 Dwarf_Attribute attr;
187 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
190 /* TODO: handle more than 1 exprs */
191 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
192 return -EINVAL; /* Broken DIE ? */
193 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
194 ret = dwarf_entrypc(sp_die, &tmp);
198 if (probe_conf.show_location_range &&
199 (dwarf_tag(vr_die) == DW_TAG_variable)) {
201 } else if (addr != tmp ||
202 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
206 ret = dwarf_highpc(sp_die, &tmp);
210 * This is fuzzed by fentry mcount. We try to find the
211 * parameter location at the earliest address.
213 for (addr += 1; addr <= tmp; addr++) {
214 if (dwarf_getlocation_addr(&attr, addr, &op,
222 /* TODO: Support const_value */
225 if (op->atom == DW_OP_addr) {
229 /* Static variables on memory (not stack), make @varname */
230 ret = strlen(dwarf_diename(vr_die));
231 tvar->value = zalloc(ret + 2);
232 if (tvar->value == NULL)
234 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
235 tvar->ref = alloc_trace_arg_ref((long)offs);
236 if (tvar->ref == NULL)
241 /* If this is based on frame buffer, set the offset */
242 if (op->atom == DW_OP_fbreg) {
250 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
251 regn = op->atom - DW_OP_breg0;
254 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
255 regn = op->atom - DW_OP_reg0;
256 } else if (op->atom == DW_OP_bregx) {
260 } else if (op->atom == DW_OP_regx) {
263 pr_debug("DW_OP %x is not supported.\n", op->atom);
270 regs = get_dwarf_regstr(regn, machine);
272 /* This should be a bug in DWARF or this tool */
273 pr_warning("Mapping for the register number %u "
274 "missing on this architecture.\n", regn);
278 tvar->value = strdup(regs);
279 if (tvar->value == NULL)
283 tvar->ref = alloc_trace_arg_ref((long)offs);
284 if (tvar->ref == NULL)
290 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
292 static int convert_variable_type(Dwarf_Die *vr_die,
293 struct probe_trace_arg *tvar,
296 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
299 char sbuf[STRERR_BUFSIZE];
300 int bsize, boffs, total;
304 /* TODO: check all types */
305 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
306 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
307 /* Non string type is OK */
308 /* and respect signedness/hexadecimal cast */
309 tvar->type = strdup(cast);
310 return (tvar->type == NULL) ? -ENOMEM : 0;
313 bsize = dwarf_bitsize(vr_die);
315 /* This is a bitfield */
316 boffs = dwarf_bitoffset(vr_die);
317 total = dwarf_bytesize(vr_die);
318 if (boffs < 0 || total < 0)
320 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
321 BYTES_TO_BITS(total));
325 if (die_get_real_type(vr_die, &type) == NULL) {
326 pr_warning("Failed to get a type information of %s.\n",
327 dwarf_diename(vr_die));
331 pr_debug("%s type is %s.\n",
332 dwarf_diename(vr_die), dwarf_diename(&type));
334 if (cast && strcmp(cast, "string") == 0) { /* String type */
335 ret = dwarf_tag(&type);
336 if (ret != DW_TAG_pointer_type &&
337 ret != DW_TAG_array_type) {
338 pr_warning("Failed to cast into string: "
339 "%s(%s) is not a pointer nor array.\n",
340 dwarf_diename(vr_die), dwarf_diename(&type));
343 if (die_get_real_type(&type, &type) == NULL) {
344 pr_warning("Failed to get a type"
348 if (ret == DW_TAG_pointer_type) {
350 ref_ptr = &(*ref_ptr)->next;
351 /* Add new reference with offset +0 */
352 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
353 if (*ref_ptr == NULL) {
354 pr_warning("Out of memory error\n");
358 if (!die_compare_name(&type, "char") &&
359 !die_compare_name(&type, "unsigned char")) {
360 pr_warning("Failed to cast into string: "
361 "%s is not (unsigned) char *.\n",
362 dwarf_diename(vr_die));
365 tvar->type = strdup(cast);
366 return (tvar->type == NULL) ? -ENOMEM : 0;
369 if (cast && (strcmp(cast, "u") == 0))
371 else if (cast && (strcmp(cast, "s") == 0))
373 else if (cast && (strcmp(cast, "x") == 0) &&
374 probe_type_is_available(PROBE_TYPE_X))
377 prefix = die_is_signed_type(&type) ? 's' :
378 probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
380 ret = dwarf_bytesize(&type);
382 /* No size ... try to use default type */
384 ret = BYTES_TO_BITS(ret);
386 /* Check the bitwidth */
387 if (ret > MAX_BASIC_TYPE_BITS) {
388 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
389 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
390 ret = MAX_BASIC_TYPE_BITS;
392 ret = snprintf(buf, 16, "%c%d", prefix, ret);
395 if (ret < 0 || ret >= 16) {
398 pr_warning("Failed to convert variable type: %s\n",
399 str_error_r(-ret, sbuf, sizeof(sbuf)));
402 tvar->type = strdup(buf);
403 if (tvar->type == NULL)
408 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
409 struct perf_probe_arg_field *field,
410 struct probe_trace_arg_ref **ref_ptr,
413 struct probe_trace_arg_ref *ref = *ref_ptr;
418 pr_debug("converting %s in %s\n", field->name, varname);
419 if (die_get_real_type(vr_die, &type) == NULL) {
420 pr_warning("Failed to get the type of %s.\n", varname);
423 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
424 tag = dwarf_tag(&type);
426 if (field->name[0] == '[' &&
427 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
429 /* Save original type for next field */
430 memcpy(die_mem, &type, sizeof(*die_mem));
431 /* Get the type of this array */
432 if (die_get_real_type(&type, &type) == NULL) {
433 pr_warning("Failed to get the type of %s.\n", varname);
436 pr_debug2("Array real type: (%x)\n",
437 (unsigned)dwarf_dieoffset(&type));
438 if (tag == DW_TAG_pointer_type) {
439 ref = zalloc(sizeof(struct probe_trace_arg_ref));
443 (*ref_ptr)->next = ref;
447 ref->offset += dwarf_bytesize(&type) * field->index;
449 /* Save vr_die for converting types */
450 memcpy(die_mem, vr_die, sizeof(*die_mem));
452 } else if (tag == DW_TAG_pointer_type) {
453 /* Check the pointer and dereference */
455 pr_err("Semantic error: %s must be referred by '->'\n",
459 /* Get the type pointed by this pointer */
460 if (die_get_real_type(&type, &type) == NULL) {
461 pr_warning("Failed to get the type of %s.\n", varname);
464 /* Verify it is a data structure */
465 tag = dwarf_tag(&type);
466 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
467 pr_warning("%s is not a data structure nor an union.\n",
472 ref = zalloc(sizeof(struct probe_trace_arg_ref));
476 (*ref_ptr)->next = ref;
480 /* Verify it is a data structure */
481 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
482 pr_warning("%s is not a data structure nor an union.\n",
486 if (field->name[0] == '[') {
487 pr_err("Semantic error: %s is not a pointer"
488 " nor array.\n", varname);
491 /* While prcessing unnamed field, we don't care about this */
492 if (field->ref && dwarf_diename(vr_die)) {
493 pr_err("Semantic error: %s must be referred by '.'\n",
498 pr_warning("Structure on a register is not "
504 if (die_find_member(&type, field->name, die_mem) == NULL) {
505 pr_warning("%s(type:%s) has no member %s.\n", varname,
506 dwarf_diename(&type), field->name);
510 /* Get the offset of the field */
511 if (tag == DW_TAG_union_type) {
514 ret = die_get_data_member_location(die_mem, &offs);
516 pr_warning("Failed to get the offset of %s.\n",
521 ref->offset += (long)offs;
523 /* If this member is unnamed, we need to reuse this field */
524 if (!dwarf_diename(die_mem))
525 return convert_variable_fields(die_mem, varname, field,
529 /* Converting next field */
531 return convert_variable_fields(die_mem, field->name,
532 field->next, &ref, die_mem);
537 /* Show a variables in kprobe event format */
538 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
543 pr_debug("Converting variable %s into trace event.\n",
544 dwarf_diename(vr_die));
546 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
547 &pf->sp_die, pf->machine, pf->tvar);
548 if (ret == -ENOENT || ret == -EINVAL) {
549 pr_err("Failed to find the location of the '%s' variable at this address.\n"
550 " Perhaps it has been optimized out.\n"
551 " Use -V with the --range option to show '%s' location range.\n",
552 pf->pvar->var, pf->pvar->var);
553 } else if (ret == -ENOTSUP)
554 pr_err("Sorry, we don't support this variable location yet.\n");
555 else if (ret == 0 && pf->pvar->field) {
556 ret = convert_variable_fields(vr_die, pf->pvar->var,
557 pf->pvar->field, &pf->tvar->ref,
562 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
563 /* *expr will be cached in libdw. Don't free it. */
567 /* Find a variable in a scope DIE */
568 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
574 /* Copy raw parameters */
575 if (!is_c_varname(pf->pvar->var))
576 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
579 pf->tvar->name = strdup(pf->pvar->name);
581 buf = synthesize_perf_probe_arg(pf->pvar);
584 ptr = strchr(buf, ':'); /* Change type separator to _ */
587 pf->tvar->name = buf;
589 if (pf->tvar->name == NULL)
592 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
593 /* Search child die for local variables and parameters. */
594 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
595 /* Search again in global variables */
596 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
598 pr_warning("Failed to find '%s' in this function.\n",
604 ret = convert_variable(&vr_die, pf);
609 /* Convert subprogram DIE to trace point */
610 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
611 Dwarf_Addr paddr, bool retprobe,
612 const char *function,
613 struct probe_trace_point *tp)
615 Dwarf_Addr eaddr, highaddr;
619 /* Verify the address is correct */
620 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
621 pr_warning("Failed to get entry address of %s\n",
622 dwarf_diename(sp_die));
625 if (dwarf_highpc(sp_die, &highaddr) != 0) {
626 pr_warning("Failed to get end address of %s\n",
627 dwarf_diename(sp_die));
630 if (paddr > highaddr) {
631 pr_warning("Offset specified is greater than size of %s\n",
632 dwarf_diename(sp_die));
636 symbol = dwarf_diename(sp_die);
638 /* Try to get the symbol name from symtab */
639 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
641 pr_warning("Failed to find symbol at 0x%lx\n",
642 (unsigned long)paddr);
645 eaddr = sym.st_value;
647 tp->offset = (unsigned long)(paddr - eaddr);
648 tp->address = (unsigned long)paddr;
649 tp->symbol = strdup(symbol);
653 /* Return probe must be on the head of a subprogram */
655 if (eaddr != paddr) {
656 pr_warning("Failed to find \"%s%%return\",\n"
657 " because %s is an inlined function and"
658 " has no return point.\n", function,
668 /* Call probe_finder callback with scope DIE */
669 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
671 Dwarf_Attribute fb_attr;
672 Dwarf_Frame *frame = NULL;
677 pr_err("Caller must pass a scope DIE. Program error.\n");
681 /* If not a real subprogram, find a real one */
682 if (!die_is_func_def(sc_die)) {
683 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
684 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
685 pr_warning("Ignoring tail call from %s\n",
686 dwarf_diename(&pf->sp_die));
689 pr_warning("Failed to find probe point in any "
695 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
697 /* Get the frame base attribute/ops from subprogram */
698 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
699 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
700 if (ret <= 0 || nops == 0) {
702 #if _ELFUTILS_PREREQ(0, 142)
703 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
704 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
705 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
706 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
707 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
708 pr_warning("Failed to get call frame on 0x%jx\n",
709 (uintmax_t)pf->addr);
716 /* Call finder's callback handler */
717 ret = pf->callback(sc_die, pf);
719 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
726 struct find_scope_param {
727 const char *function;
735 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
737 struct find_scope_param *fsp = data;
741 /* Skip if declared file name does not match */
743 file = dwarf_decl_file(fn_die);
744 if (!file || strcmp(fsp->file, file) != 0)
747 /* If the function name is given, that's what user expects */
749 if (die_match_name(fn_die, fsp->function)) {
750 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
755 /* With the line number, find the nearest declared DIE */
756 dwarf_decl_line(fn_die, &lno);
757 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
758 /* Keep a candidate and continue */
759 fsp->diff = fsp->line - lno;
760 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
767 /* Find an appropriate scope fits to given conditions */
768 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
770 struct find_scope_param fsp = {
771 .function = pf->pev->point.function,
779 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
781 return fsp.found ? die_mem : NULL;
784 static int probe_point_line_walker(const char *fname, int lineno,
785 Dwarf_Addr addr, void *data)
787 struct probe_finder *pf = data;
788 Dwarf_Die *sc_die, die_mem;
791 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
795 sc_die = find_best_scope(pf, &die_mem);
797 pr_warning("Failed to find scope of probe point.\n");
801 ret = call_probe_finder(sc_die, pf);
803 /* Continue if no error, because the line will be in inline function */
804 return ret < 0 ? ret : 0;
807 /* Find probe point from its line number */
808 static int find_probe_point_by_line(struct probe_finder *pf)
810 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
813 /* Find lines which match lazy pattern */
814 static int find_lazy_match_lines(struct intlist *list,
815 const char *fname, const char *pat)
821 int count = 0, linenum = 1;
822 char sbuf[STRERR_BUFSIZE];
824 fp = fopen(fname, "r");
826 pr_warning("Failed to open %s: %s\n", fname,
827 str_error_r(errno, sbuf, sizeof(sbuf)));
831 while ((len = getline(&line, &line_len, fp)) > 0) {
833 if (line[len - 1] == '\n')
834 line[len - 1] = '\0';
836 if (strlazymatch(line, pat)) {
837 intlist__add(list, linenum);
849 pr_debug("No matched lines found in %s.\n", fname);
853 static int probe_point_lazy_walker(const char *fname, int lineno,
854 Dwarf_Addr addr, void *data)
856 struct probe_finder *pf = data;
857 Dwarf_Die *sc_die, die_mem;
860 if (!intlist__has_entry(pf->lcache, lineno) ||
861 strtailcmp(fname, pf->fname) != 0)
864 pr_debug("Probe line found: line:%d addr:0x%llx\n",
865 lineno, (unsigned long long)addr);
868 sc_die = find_best_scope(pf, &die_mem);
870 pr_warning("Failed to find scope of probe point.\n");
874 ret = call_probe_finder(sc_die, pf);
877 * Continue if no error, because the lazy pattern will match
880 return ret < 0 ? ret : 0;
883 /* Find probe points from lazy pattern */
884 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
889 if (intlist__empty(pf->lcache)) {
890 const char *comp_dir;
892 comp_dir = cu_get_comp_dir(&pf->cu_die);
893 ret = get_real_path(pf->fname, comp_dir, &fpath);
895 pr_warning("Failed to find source file path.\n");
899 /* Matching lazy line pattern */
900 ret = find_lazy_match_lines(pf->lcache, fpath,
901 pf->pev->point.lazy_line);
907 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
910 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
912 struct perf_probe_point *pp = &pf->pev->point;
915 if (!pf->pev->uprobes)
918 /* Compiled with optimization? */
919 if (die_is_optimized_target(&pf->cu_die))
922 /* Don't know entrypc? */
926 /* Only FUNC and FUNC@SRC are eligible. */
927 if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
928 pp->offset || pp->abs_address)
931 /* Not interested in func parameter? */
932 if (!perf_probe_with_var(pf->pev))
935 pr_info("Target program is compiled without optimization. Skipping prologue.\n"
936 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
939 die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
942 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
944 struct probe_finder *pf = data;
945 struct perf_probe_point *pp = &pf->pev->point;
950 ret = find_probe_point_lazy(in_die, pf);
952 /* Get probe address */
953 if (dwarf_entrypc(in_die, &addr) != 0) {
954 pr_warning("Failed to get entry address of %s.\n",
955 dwarf_diename(in_die));
959 pr_debug("%s has no valid entry address. skipped.\n",
960 dwarf_diename(in_die));
964 pf->addr += pp->offset;
965 pr_debug("found inline addr: 0x%jx\n",
966 (uintmax_t)pf->addr);
968 ret = call_probe_finder(in_die, pf);
974 /* Callback parameter with return value for libdw */
975 struct dwarf_callback_param {
980 /* Search function from function name */
981 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
983 struct dwarf_callback_param *param = data;
984 struct probe_finder *pf = param->data;
985 struct perf_probe_point *pp = &pf->pev->point;
987 /* Check tag and diename */
988 if (!die_is_func_def(sp_die) ||
989 !die_match_name(sp_die, pp->function))
992 /* Check declared file */
993 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
996 pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
997 (unsigned long)dwarf_dieoffset(sp_die));
998 pf->fname = dwarf_decl_file(sp_die);
999 if (pp->line) { /* Function relative line */
1000 dwarf_decl_line(sp_die, &pf->lno);
1001 pf->lno += pp->line;
1002 param->retval = find_probe_point_by_line(pf);
1003 } else if (die_is_func_instance(sp_die)) {
1004 /* Instances always have the entry address */
1005 dwarf_entrypc(sp_die, &pf->addr);
1006 /* But in some case the entry address is 0 */
1007 if (pf->addr == 0) {
1008 pr_debug("%s has no entry PC. Skipped\n",
1009 dwarf_diename(sp_die));
1012 } else if (pp->lazy_line)
1013 param->retval = find_probe_point_lazy(sp_die, pf);
1015 skip_prologue(sp_die, pf);
1016 pf->addr += pp->offset;
1017 /* TODO: Check the address in this function */
1018 param->retval = call_probe_finder(sp_die, pf);
1020 } else if (!probe_conf.no_inlines) {
1021 /* Inlined function: search instances */
1022 param->retval = die_walk_instances(sp_die,
1023 probe_point_inline_cb, (void *)pf);
1024 /* This could be a non-existed inline definition */
1025 if (param->retval == -ENOENT)
1029 /* We need to find other candidates */
1030 if (strisglob(pp->function) && param->retval >= 0) {
1031 param->retval = 0; /* We have to clear the result */
1035 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1038 static int find_probe_point_by_func(struct probe_finder *pf)
1040 struct dwarf_callback_param _param = {.data = (void *)pf,
1042 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1043 return _param.retval;
1046 struct pubname_callback_param {
1054 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1056 struct pubname_callback_param *param = data;
1058 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1059 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1062 if (die_match_name(param->sp_die, param->function)) {
1063 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1067 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1071 return DWARF_CB_ABORT;
1078 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1079 struct probe_finder *pf)
1081 struct perf_probe_point *pp = &pf->pev->point;
1082 Dwarf_Off off, noff;
1088 pf->lcache = intlist__new(NULL);
1092 /* Fastpath: lookup by function name from .debug_pubnames section */
1093 if (pp->function && !strisglob(pp->function)) {
1094 struct pubname_callback_param pubname_param = {
1095 .function = pp->function,
1097 .cu_die = &pf->cu_die,
1098 .sp_die = &pf->sp_die,
1101 struct dwarf_callback_param probe_param = {
1105 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1107 if (pubname_param.found) {
1108 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1114 /* Loop on CUs (Compilation Unit) */
1115 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1116 /* Get the DIE(Debugging Information Entry) of this CU */
1117 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1121 /* Check if target file is included. */
1123 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1127 if (!pp->file || pf->fname) {
1129 ret = find_probe_point_by_func(pf);
1130 else if (pp->lazy_line)
1131 ret = find_probe_point_lazy(&pf->cu_die, pf);
1134 ret = find_probe_point_by_line(pf);
1143 intlist__delete(pf->lcache);
1149 /* Find probe points from debuginfo */
1150 static int debuginfo__find_probes(struct debuginfo *dbg,
1151 struct probe_finder *pf)
1157 if (pf->cfi_eh || pf->cfi_dbg)
1158 return debuginfo__find_probe_location(dbg, pf);
1160 /* Get the call frame information from this dwarf */
1161 elf = dwarf_getelf(dbg->dbg);
1165 if (gelf_getehdr(elf, &ehdr) == NULL)
1168 pf->machine = ehdr.e_machine;
1170 #if _ELFUTILS_PREREQ(0, 142)
1174 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1175 shdr.sh_type == SHT_PROGBITS)
1176 pf->cfi_eh = dwarf_getcfi_elf(elf);
1178 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1182 ret = debuginfo__find_probe_location(dbg, pf);
1186 struct local_vars_finder {
1187 struct probe_finder *pf;
1188 struct perf_probe_arg *args;
1195 /* Collect available variables in this scope */
1196 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1198 struct local_vars_finder *vf = data;
1199 struct probe_finder *pf = vf->pf;
1202 tag = dwarf_tag(die_mem);
1203 if (tag == DW_TAG_formal_parameter ||
1204 (tag == DW_TAG_variable && vf->vars)) {
1205 if (convert_variable_location(die_mem, vf->pf->addr,
1206 vf->pf->fb_ops, &pf->sp_die,
1207 pf->machine, NULL) == 0) {
1208 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1209 if (vf->args[vf->nargs].var == NULL) {
1211 return DIE_FIND_CB_END;
1213 pr_debug(" %s", vf->args[vf->nargs].var);
1218 if (dwarf_haspc(die_mem, vf->pf->addr))
1219 return DIE_FIND_CB_CONTINUE;
1221 return DIE_FIND_CB_SIBLING;
1224 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1225 struct perf_probe_arg *args)
1230 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1231 .max_args = MAX_PROBE_ARGS, .ret = 0};
1233 for (i = 0; i < pf->pev->nargs; i++) {
1234 /* var never be NULL */
1235 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1237 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1238 /* Copy normal argument */
1239 args[n] = pf->pev->args[i];
1243 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1245 /* Special local variables */
1246 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1248 pr_debug(" (%d)\n", vf.nargs - n);
1256 /* Add a found probe point into trace event list */
1257 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1259 struct trace_event_finder *tf =
1260 container_of(pf, struct trace_event_finder, pf);
1261 struct perf_probe_point *pp = &pf->pev->point;
1262 struct probe_trace_event *tev;
1263 struct perf_probe_arg *args = NULL;
1266 /* Check number of tevs */
1267 if (tf->ntevs == tf->max_tevs) {
1268 pr_warning("Too many( > %d) probe point found.\n",
1272 tev = &tf->tevs[tf->ntevs++];
1274 /* Trace point should be converted from subprogram DIE */
1275 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1276 pp->retprobe, pp->function, &tev->point);
1280 tev->point.realname = strdup(dwarf_diename(sc_die));
1281 if (!tev->point.realname) {
1286 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1289 /* Expand special probe argument if exist */
1290 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1296 ret = expand_probe_args(sc_die, pf, args);
1301 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1302 if (tev->args == NULL) {
1307 /* Find each argument */
1308 for (i = 0; i < tev->nargs; i++) {
1309 pf->pvar = &args[i];
1310 pf->tvar = &tev->args[i];
1311 /* Variable should be found from scope DIE */
1312 ret = find_variable(sc_die, pf);
1319 clear_probe_trace_event(tev);
1326 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1327 int debuginfo__find_trace_events(struct debuginfo *dbg,
1328 struct perf_probe_event *pev,
1329 struct probe_trace_event **tevs)
1331 struct trace_event_finder tf = {
1332 .pf = {.pev = pev, .callback = add_probe_trace_event},
1333 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1336 /* Allocate result tevs array */
1337 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1344 ret = debuginfo__find_probes(dbg, &tf.pf);
1346 for (i = 0; i < tf.ntevs; i++)
1347 clear_probe_trace_event(&tf.tevs[i]);
1352 return (ret < 0) ? ret : tf.ntevs;
1355 /* Collect available variables in this scope */
1356 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1358 struct available_var_finder *af = data;
1359 struct variable_list *vl;
1360 struct strbuf buf = STRBUF_INIT;
1363 vl = &af->vls[af->nvls - 1];
1365 tag = dwarf_tag(die_mem);
1366 if (tag == DW_TAG_formal_parameter ||
1367 tag == DW_TAG_variable) {
1368 ret = convert_variable_location(die_mem, af->pf.addr,
1369 af->pf.fb_ops, &af->pf.sp_die,
1370 af->pf.machine, NULL);
1371 if (ret == 0 || ret == -ERANGE) {
1373 bool externs = !af->child;
1375 if (strbuf_init(&buf, 64) < 0)
1378 if (probe_conf.show_location_range) {
1380 ret2 = strbuf_add(&buf,
1381 ret ? "[INV]\t" : "[VAL]\t", 6);
1383 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1388 ret2 = die_get_varname(die_mem, &buf);
1390 if (!ret2 && probe_conf.show_location_range &&
1392 if (strbuf_addch(&buf, '\t') < 0)
1394 ret2 = die_get_var_range(&af->pf.sp_die,
1398 pr_debug("Add new var: %s\n", buf.buf);
1400 strlist__add(vl->vars,
1401 strbuf_detach(&buf, NULL));
1403 strbuf_release(&buf);
1407 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1408 return DIE_FIND_CB_CONTINUE;
1410 return DIE_FIND_CB_SIBLING;
1412 strbuf_release(&buf);
1413 pr_debug("Error in strbuf\n");
1414 return DIE_FIND_CB_END;
1417 /* Add a found vars into available variables list */
1418 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1420 struct available_var_finder *af =
1421 container_of(pf, struct available_var_finder, pf);
1422 struct perf_probe_point *pp = &pf->pev->point;
1423 struct variable_list *vl;
1427 /* Check number of tevs */
1428 if (af->nvls == af->max_vls) {
1429 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1432 vl = &af->vls[af->nvls++];
1434 /* Trace point should be converted from subprogram DIE */
1435 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1436 pp->retprobe, pp->function, &vl->point);
1440 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1443 /* Find local variables */
1444 vl->vars = strlist__new(NULL, NULL);
1445 if (vl->vars == NULL)
1448 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1450 /* Find external variables */
1451 if (!probe_conf.show_ext_vars)
1453 /* Don't need to search child DIE for external vars. */
1455 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1458 if (strlist__empty(vl->vars)) {
1459 strlist__delete(vl->vars);
1467 * Find available variables at given probe point
1468 * Return the number of found probe points. Return 0 if there is no
1469 * matched probe point. Return <0 if an error occurs.
1471 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1472 struct perf_probe_event *pev,
1473 struct variable_list **vls)
1475 struct available_var_finder af = {
1476 .pf = {.pev = pev, .callback = add_available_vars},
1478 .max_vls = probe_conf.max_probes};
1481 /* Allocate result vls array */
1482 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1489 ret = debuginfo__find_probes(dbg, &af.pf);
1491 /* Free vlist for error */
1493 zfree(&af.vls[af.nvls].point.symbol);
1494 strlist__delete(af.vls[af.nvls].vars);
1500 return (ret < 0) ? ret : af.nvls;
1503 /* For the kernel module, we need a special code to get a DIE */
1504 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1511 GElf_Shdr mem, *shdr;
1514 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1518 /* Get the number of relocations */
1519 n = dwfl_module_relocations(dbg->mod);
1522 /* Search the relocation related .text section */
1523 for (i = 0; i < n; i++) {
1524 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1525 if (strcmp(p, ".text") == 0) {
1526 /* OK, get the section header */
1527 scn = elf_getscn(elf, shndx);
1530 shdr = gelf_getshdr(scn, &mem);
1533 *offs = shdr->sh_addr;
1535 *offs -= shdr->sh_offset;
1541 /* Reverse search */
1542 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1543 struct perf_probe_point *ppt)
1545 Dwarf_Die cudie, spdie, indie;
1546 Dwarf_Addr _addr = 0, baseaddr = 0;
1547 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1548 int baseline = 0, lineno = 0, ret = 0;
1550 /* We always need to relocate the address for aranges */
1551 if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1554 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1555 pr_warning("Failed to find debug information for address %lx\n",
1561 /* Find a corresponding line (filename and lineno) */
1562 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1563 /* Don't care whether it failed or not */
1565 /* Find a corresponding function (name, baseline and baseaddr) */
1566 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1567 /* Get function entry information */
1568 func = basefunc = dwarf_diename(&spdie);
1570 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1571 dwarf_decl_line(&spdie, &baseline) != 0) {
1576 fname = dwarf_decl_file(&spdie);
1577 if (addr == (unsigned long)baseaddr) {
1578 /* Function entry - Relative line number is 0 */
1583 /* Track down the inline functions step by step */
1584 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1586 /* There is an inline function */
1587 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1590 * addr is at an inline function entry.
1591 * In this case, lineno should be the call-site
1592 * line number. (overwrite lineinfo)
1594 lineno = die_get_call_lineno(&indie);
1595 fname = die_get_call_file(&indie);
1599 * addr is in an inline function body.
1600 * Since lineno points one of the lines
1601 * of the inline function, baseline should
1602 * be the entry line of the inline function.
1604 tmp = dwarf_diename(&indie);
1606 dwarf_decl_line(&indie, &baseline) != 0)
1612 /* Verify the lineno and baseline are in a same file */
1613 tmp = dwarf_decl_file(&spdie);
1614 if (!tmp || strcmp(tmp, fname) != 0)
1619 /* Make a relative line number or an offset */
1621 ppt->line = lineno - baseline;
1622 else if (basefunc) {
1623 ppt->offset = addr - (unsigned long)baseaddr;
1627 /* Duplicate strings */
1629 ppt->function = strdup(func);
1630 if (ppt->function == NULL) {
1636 ppt->file = strdup(fname);
1637 if (ppt->file == NULL) {
1638 zfree(&ppt->function);
1644 if (ret == 0 && (fname || func))
1645 ret = 1; /* Found a point */
1649 /* Add a line and store the src path */
1650 static int line_range_add_line(const char *src, unsigned int lineno,
1651 struct line_range *lr)
1653 /* Copy source path */
1655 lr->path = strdup(src);
1656 if (lr->path == NULL)
1659 return intlist__add(lr->line_list, lineno);
1662 static int line_range_walk_cb(const char *fname, int lineno,
1663 Dwarf_Addr addr __maybe_unused,
1666 struct line_finder *lf = data;
1669 if ((strtailcmp(fname, lf->fname) != 0) ||
1670 (lf->lno_s > lineno || lf->lno_e < lineno))
1673 err = line_range_add_line(fname, lineno, lf->lr);
1674 if (err < 0 && err != -EEXIST)
1680 /* Find line range from its line number */
1681 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1685 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1689 if (!intlist__empty(lf->lr->line_list))
1690 ret = lf->found = 1;
1692 ret = 0; /* Lines are not found */
1694 zfree(&lf->lr->path);
1699 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1701 int ret = find_line_range_by_line(in_die, data);
1704 * We have to check all instances of inlined function, because
1705 * some execution paths can be optimized out depends on the
1706 * function argument of instances. However, if an error occurs,
1707 * it should be handled by the caller.
1709 return ret < 0 ? ret : 0;
1712 /* Search function definition from function name */
1713 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1715 struct dwarf_callback_param *param = data;
1716 struct line_finder *lf = param->data;
1717 struct line_range *lr = lf->lr;
1719 /* Check declared file */
1720 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1723 if (die_is_func_def(sp_die) &&
1724 die_match_name(sp_die, lr->function)) {
1725 lf->fname = dwarf_decl_file(sp_die);
1726 dwarf_decl_line(sp_die, &lr->offset);
1727 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1728 lf->lno_s = lr->offset + lr->start;
1729 if (lf->lno_s < 0) /* Overflow */
1730 lf->lno_s = INT_MAX;
1731 lf->lno_e = lr->offset + lr->end;
1732 if (lf->lno_e < 0) /* Overflow */
1733 lf->lno_e = INT_MAX;
1734 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1735 lr->start = lf->lno_s;
1736 lr->end = lf->lno_e;
1737 if (!die_is_func_instance(sp_die))
1738 param->retval = die_walk_instances(sp_die,
1739 line_range_inline_cb, lf);
1741 param->retval = find_line_range_by_line(sp_die, lf);
1742 return DWARF_CB_ABORT;
1747 static int find_line_range_by_func(struct line_finder *lf)
1749 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1750 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1751 return param.retval;
1754 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1756 struct line_finder lf = {.lr = lr, .found = 0};
1758 Dwarf_Off off = 0, noff;
1761 const char *comp_dir;
1763 /* Fastpath: lookup by function name from .debug_pubnames section */
1765 struct pubname_callback_param pubname_param = {
1766 .function = lr->function, .file = lr->file,
1767 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1768 struct dwarf_callback_param line_range_param = {
1769 .data = (void *)&lf, .retval = 0};
1771 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1773 if (pubname_param.found) {
1774 line_range_search_cb(&lf.sp_die, &line_range_param);
1780 /* Loop on CUs (Compilation Unit) */
1781 while (!lf.found && ret >= 0) {
1782 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1783 NULL, NULL, NULL) != 0)
1786 /* Get the DIE(Debugging Information Entry) of this CU */
1787 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1791 /* Check if target file is included. */
1793 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1797 if (!lr->file || lf.fname) {
1799 ret = find_line_range_by_func(&lf);
1801 lf.lno_s = lr->start;
1803 ret = find_line_range_by_line(NULL, &lf);
1810 /* Store comp_dir */
1812 comp_dir = cu_get_comp_dir(&lf.cu_die);
1814 lr->comp_dir = strdup(comp_dir);
1820 pr_debug("path: %s\n", lr->path);
1821 return (ret < 0) ? ret : lf.found;
1825 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1826 * and chop off leading directories that do not exist. Result is passed back as
1827 * a newly allocated path on success.
1828 * Return 0 if file was found and readable, -errno otherwise.
1830 int get_real_path(const char *raw_path, const char *comp_dir,
1833 const char *prefix = symbol_conf.source_prefix;
1836 if (raw_path[0] != '/' && comp_dir)
1837 /* If not an absolute path, try to use comp_dir */
1840 if (access(raw_path, R_OK) == 0) {
1841 *new_path = strdup(raw_path);
1842 return *new_path ? 0 : -ENOMEM;
1848 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1853 sprintf(*new_path, "%s/%s", prefix, raw_path);
1855 if (access(*new_path, R_OK) == 0)
1858 if (!symbol_conf.source_prefix) {
1859 /* In case of searching comp_dir, don't retry */
1869 raw_path = strchr(++raw_path, '/');