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;
301 /* TODO: check all types */
302 if (cast && strcmp(cast, "string") != 0) {
303 /* Non string type is OK */
304 tvar->type = strdup(cast);
305 return (tvar->type == NULL) ? -ENOMEM : 0;
308 bsize = dwarf_bitsize(vr_die);
310 /* This is a bitfield */
311 boffs = dwarf_bitoffset(vr_die);
312 total = dwarf_bytesize(vr_die);
313 if (boffs < 0 || total < 0)
315 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
316 BYTES_TO_BITS(total));
320 if (die_get_real_type(vr_die, &type) == NULL) {
321 pr_warning("Failed to get a type information of %s.\n",
322 dwarf_diename(vr_die));
326 pr_debug("%s type is %s.\n",
327 dwarf_diename(vr_die), dwarf_diename(&type));
329 if (cast && strcmp(cast, "string") == 0) { /* String type */
330 ret = dwarf_tag(&type);
331 if (ret != DW_TAG_pointer_type &&
332 ret != DW_TAG_array_type) {
333 pr_warning("Failed to cast into string: "
334 "%s(%s) is not a pointer nor array.\n",
335 dwarf_diename(vr_die), dwarf_diename(&type));
338 if (die_get_real_type(&type, &type) == NULL) {
339 pr_warning("Failed to get a type"
343 if (ret == DW_TAG_pointer_type) {
345 ref_ptr = &(*ref_ptr)->next;
346 /* Add new reference with offset +0 */
347 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
348 if (*ref_ptr == NULL) {
349 pr_warning("Out of memory error\n");
353 if (!die_compare_name(&type, "char") &&
354 !die_compare_name(&type, "unsigned char")) {
355 pr_warning("Failed to cast into string: "
356 "%s is not (unsigned) char *.\n",
357 dwarf_diename(vr_die));
360 tvar->type = strdup(cast);
361 return (tvar->type == NULL) ? -ENOMEM : 0;
364 ret = dwarf_bytesize(&type);
366 /* No size ... try to use default type */
368 ret = BYTES_TO_BITS(ret);
370 /* Check the bitwidth */
371 if (ret > MAX_BASIC_TYPE_BITS) {
372 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
373 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
374 ret = MAX_BASIC_TYPE_BITS;
376 ret = snprintf(buf, 16, "%c%d",
377 die_is_signed_type(&type) ? 's' : 'u', ret);
380 if (ret < 0 || ret >= 16) {
383 pr_warning("Failed to convert variable type: %s\n",
384 strerror_r(-ret, sbuf, sizeof(sbuf)));
387 tvar->type = strdup(buf);
388 if (tvar->type == NULL)
393 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
394 struct perf_probe_arg_field *field,
395 struct probe_trace_arg_ref **ref_ptr,
398 struct probe_trace_arg_ref *ref = *ref_ptr;
403 pr_debug("converting %s in %s\n", field->name, varname);
404 if (die_get_real_type(vr_die, &type) == NULL) {
405 pr_warning("Failed to get the type of %s.\n", varname);
408 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
409 tag = dwarf_tag(&type);
411 if (field->name[0] == '[' &&
412 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
414 /* Save original type for next field */
415 memcpy(die_mem, &type, sizeof(*die_mem));
416 /* Get the type of this array */
417 if (die_get_real_type(&type, &type) == NULL) {
418 pr_warning("Failed to get the type of %s.\n", varname);
421 pr_debug2("Array real type: (%x)\n",
422 (unsigned)dwarf_dieoffset(&type));
423 if (tag == DW_TAG_pointer_type) {
424 ref = zalloc(sizeof(struct probe_trace_arg_ref));
428 (*ref_ptr)->next = ref;
432 ref->offset += dwarf_bytesize(&type) * field->index;
434 /* Save vr_die for converting types */
435 memcpy(die_mem, vr_die, sizeof(*die_mem));
437 } else if (tag == DW_TAG_pointer_type) {
438 /* Check the pointer and dereference */
440 pr_err("Semantic error: %s must be referred by '->'\n",
444 /* Get the type pointed by this pointer */
445 if (die_get_real_type(&type, &type) == NULL) {
446 pr_warning("Failed to get the type of %s.\n", varname);
449 /* Verify it is a data structure */
450 tag = dwarf_tag(&type);
451 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
452 pr_warning("%s is not a data structure nor an union.\n",
457 ref = zalloc(sizeof(struct probe_trace_arg_ref));
461 (*ref_ptr)->next = ref;
465 /* Verify it is a data structure */
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",
471 if (field->name[0] == '[') {
472 pr_err("Semantic error: %s is not a pointer"
473 " nor array.\n", varname);
476 /* While prcessing unnamed field, we don't care about this */
477 if (field->ref && dwarf_diename(vr_die)) {
478 pr_err("Semantic error: %s must be referred by '.'\n",
483 pr_warning("Structure on a register is not "
489 if (die_find_member(&type, field->name, die_mem) == NULL) {
490 pr_warning("%s(type:%s) has no member %s.\n", varname,
491 dwarf_diename(&type), field->name);
495 /* Get the offset of the field */
496 if (tag == DW_TAG_union_type) {
499 ret = die_get_data_member_location(die_mem, &offs);
501 pr_warning("Failed to get the offset of %s.\n",
506 ref->offset += (long)offs;
508 /* If this member is unnamed, we need to reuse this field */
509 if (!dwarf_diename(die_mem))
510 return convert_variable_fields(die_mem, varname, field,
514 /* Converting next field */
516 return convert_variable_fields(die_mem, field->name,
517 field->next, &ref, die_mem);
522 /* Show a variables in kprobe event format */
523 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
528 pr_debug("Converting variable %s into trace event.\n",
529 dwarf_diename(vr_die));
531 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
532 &pf->sp_die, pf->tvar);
533 if (ret == -ENOENT || ret == -EINVAL) {
534 pr_err("Failed to find the location of the '%s' variable at this address.\n"
535 " Perhaps it has been optimized out.\n"
536 " Use -V with the --range option to show '%s' location range.\n",
537 pf->pvar->var, pf->pvar->var);
538 } else if (ret == -ENOTSUP)
539 pr_err("Sorry, we don't support this variable location yet.\n");
540 else if (ret == 0 && pf->pvar->field) {
541 ret = convert_variable_fields(vr_die, pf->pvar->var,
542 pf->pvar->field, &pf->tvar->ref,
547 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
548 /* *expr will be cached in libdw. Don't free it. */
552 /* Find a variable in a scope DIE */
553 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
559 /* Copy raw parameters */
560 if (!is_c_varname(pf->pvar->var))
561 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
564 pf->tvar->name = strdup(pf->pvar->name);
566 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
569 ptr = strchr(buf, ':'); /* Change type separator to _ */
572 pf->tvar->name = strdup(buf);
574 if (pf->tvar->name == NULL)
577 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
578 /* Search child die for local variables and parameters. */
579 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
580 /* Search again in global variables */
581 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
583 pr_warning("Failed to find '%s' in this function.\n",
589 ret = convert_variable(&vr_die, pf);
594 /* Convert subprogram DIE to trace point */
595 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
596 Dwarf_Addr paddr, bool retprobe,
597 const char *function,
598 struct probe_trace_point *tp)
600 Dwarf_Addr eaddr, highaddr;
604 /* Verify the address is correct */
605 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
606 pr_warning("Failed to get entry address of %s\n",
607 dwarf_diename(sp_die));
610 if (dwarf_highpc(sp_die, &highaddr) != 0) {
611 pr_warning("Failed to get end address of %s\n",
612 dwarf_diename(sp_die));
615 if (paddr > highaddr) {
616 pr_warning("Offset specified is greater than size of %s\n",
617 dwarf_diename(sp_die));
621 symbol = dwarf_diename(sp_die);
623 /* Try to get the symbol name from symtab */
624 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
626 pr_warning("Failed to find symbol at 0x%lx\n",
627 (unsigned long)paddr);
630 eaddr = sym.st_value;
632 tp->offset = (unsigned long)(paddr - eaddr);
633 tp->address = (unsigned long)paddr;
634 tp->symbol = strdup(symbol);
638 /* Return probe must be on the head of a subprogram */
640 if (eaddr != paddr) {
641 pr_warning("Failed to find \"%s%%return\",\n"
642 " because %s is an inlined function and"
643 " has no return point.\n", function,
653 /* Call probe_finder callback with scope DIE */
654 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
656 Dwarf_Attribute fb_attr;
661 pr_err("Caller must pass a scope DIE. Program error.\n");
665 /* If not a real subprogram, find a real one */
666 if (!die_is_func_def(sc_die)) {
667 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
668 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
669 pr_warning("Ignoring tail call from %s\n",
670 dwarf_diename(&pf->sp_die));
673 pr_warning("Failed to find probe point in any "
679 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
681 /* Get the frame base attribute/ops from subprogram */
682 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
683 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
684 if (ret <= 0 || nops == 0) {
686 #if _ELFUTILS_PREREQ(0, 142)
687 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
690 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
691 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
692 pr_warning("Failed to get call frame on 0x%jx\n",
693 (uintmax_t)pf->addr);
699 /* Call finder's callback handler */
700 ret = pf->callback(sc_die, pf);
702 /* *pf->fb_ops will be cached in libdw. Don't free it. */
708 struct find_scope_param {
709 const char *function;
717 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
719 struct find_scope_param *fsp = data;
723 /* Skip if declared file name does not match */
725 file = dwarf_decl_file(fn_die);
726 if (!file || strcmp(fsp->file, file) != 0)
729 /* If the function name is given, that's what user expects */
731 if (die_match_name(fn_die, fsp->function)) {
732 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
737 /* With the line number, find the nearest declared DIE */
738 dwarf_decl_line(fn_die, &lno);
739 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
740 /* Keep a candidate and continue */
741 fsp->diff = fsp->line - lno;
742 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
749 /* Find an appropriate scope fits to given conditions */
750 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
752 struct find_scope_param fsp = {
753 .function = pf->pev->point.function,
761 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
763 return fsp.found ? die_mem : NULL;
766 static int probe_point_line_walker(const char *fname, int lineno,
767 Dwarf_Addr addr, void *data)
769 struct probe_finder *pf = data;
770 Dwarf_Die *sc_die, die_mem;
773 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
777 sc_die = find_best_scope(pf, &die_mem);
779 pr_warning("Failed to find scope of probe point.\n");
783 ret = call_probe_finder(sc_die, pf);
785 /* Continue if no error, because the line will be in inline function */
786 return ret < 0 ? ret : 0;
789 /* Find probe point from its line number */
790 static int find_probe_point_by_line(struct probe_finder *pf)
792 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
795 /* Find lines which match lazy pattern */
796 static int find_lazy_match_lines(struct intlist *list,
797 const char *fname, const char *pat)
803 int count = 0, linenum = 1;
804 char sbuf[STRERR_BUFSIZE];
806 fp = fopen(fname, "r");
808 pr_warning("Failed to open %s: %s\n", fname,
809 strerror_r(errno, sbuf, sizeof(sbuf)));
813 while ((len = getline(&line, &line_len, fp)) > 0) {
815 if (line[len - 1] == '\n')
816 line[len - 1] = '\0';
818 if (strlazymatch(line, pat)) {
819 intlist__add(list, linenum);
831 pr_debug("No matched lines found in %s.\n", fname);
835 static int probe_point_lazy_walker(const char *fname, int lineno,
836 Dwarf_Addr addr, void *data)
838 struct probe_finder *pf = data;
839 Dwarf_Die *sc_die, die_mem;
842 if (!intlist__has_entry(pf->lcache, lineno) ||
843 strtailcmp(fname, pf->fname) != 0)
846 pr_debug("Probe line found: line:%d addr:0x%llx\n",
847 lineno, (unsigned long long)addr);
850 sc_die = find_best_scope(pf, &die_mem);
852 pr_warning("Failed to find scope of probe point.\n");
856 ret = call_probe_finder(sc_die, pf);
859 * Continue if no error, because the lazy pattern will match
862 return ret < 0 ? ret : 0;
865 /* Find probe points from lazy pattern */
866 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
871 if (intlist__empty(pf->lcache)) {
872 const char *comp_dir;
874 comp_dir = cu_get_comp_dir(&pf->cu_die);
875 ret = get_real_path(pf->fname, comp_dir, &fpath);
877 pr_warning("Failed to find source file path.\n");
881 /* Matching lazy line pattern */
882 ret = find_lazy_match_lines(pf->lcache, fpath,
883 pf->pev->point.lazy_line);
889 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
892 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
894 struct probe_finder *pf = data;
895 struct perf_probe_point *pp = &pf->pev->point;
900 ret = find_probe_point_lazy(in_die, pf);
902 /* Get probe address */
903 if (dwarf_entrypc(in_die, &addr) != 0) {
904 pr_warning("Failed to get entry address of %s.\n",
905 dwarf_diename(in_die));
909 pf->addr += pp->offset;
910 pr_debug("found inline addr: 0x%jx\n",
911 (uintmax_t)pf->addr);
913 ret = call_probe_finder(in_die, pf);
919 /* Callback parameter with return value for libdw */
920 struct dwarf_callback_param {
925 /* Search function from function name */
926 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
928 struct dwarf_callback_param *param = data;
929 struct probe_finder *pf = param->data;
930 struct perf_probe_point *pp = &pf->pev->point;
932 /* Check tag and diename */
933 if (!die_is_func_def(sp_die) ||
934 !die_match_name(sp_die, pp->function))
937 /* Check declared file */
938 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
941 pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
942 pf->fname = dwarf_decl_file(sp_die);
943 if (pp->line) { /* Function relative line */
944 dwarf_decl_line(sp_die, &pf->lno);
946 param->retval = find_probe_point_by_line(pf);
947 } else if (die_is_func_instance(sp_die)) {
948 /* Instances always have the entry address */
949 dwarf_entrypc(sp_die, &pf->addr);
952 param->retval = find_probe_point_lazy(sp_die, pf);
954 pf->addr += pp->offset;
955 /* TODO: Check the address in this function */
956 param->retval = call_probe_finder(sp_die, pf);
958 } else if (!probe_conf.no_inlines) {
959 /* Inlined function: search instances */
960 param->retval = die_walk_instances(sp_die,
961 probe_point_inline_cb, (void *)pf);
962 /* This could be a non-existed inline definition */
963 if (param->retval == -ENOENT && strisglob(pp->function))
967 /* We need to find other candidates */
968 if (strisglob(pp->function) && param->retval >= 0) {
969 param->retval = 0; /* We have to clear the result */
973 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
976 static int find_probe_point_by_func(struct probe_finder *pf)
978 struct dwarf_callback_param _param = {.data = (void *)pf,
980 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
981 return _param.retval;
984 struct pubname_callback_param {
992 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
994 struct pubname_callback_param *param = data;
996 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
997 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1000 if (die_match_name(param->sp_die, param->function)) {
1001 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1005 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1009 return DWARF_CB_ABORT;
1016 /* Find probe points from debuginfo */
1017 static int debuginfo__find_probes(struct debuginfo *dbg,
1018 struct probe_finder *pf)
1020 struct perf_probe_point *pp = &pf->pev->point;
1021 Dwarf_Off off, noff;
1026 #if _ELFUTILS_PREREQ(0, 142)
1031 /* Get the call frame information from this dwarf */
1032 elf = dwarf_getelf(dbg->dbg);
1036 if (gelf_getehdr(elf, &ehdr) == NULL)
1039 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1040 shdr.sh_type == SHT_PROGBITS) {
1041 pf->cfi = dwarf_getcfi_elf(elf);
1043 pf->cfi = dwarf_getcfi(dbg->dbg);
1048 pf->lcache = intlist__new(NULL);
1052 /* Fastpath: lookup by function name from .debug_pubnames section */
1053 if (pp->function && !strisglob(pp->function)) {
1054 struct pubname_callback_param pubname_param = {
1055 .function = pp->function,
1057 .cu_die = &pf->cu_die,
1058 .sp_die = &pf->sp_die,
1061 struct dwarf_callback_param probe_param = {
1065 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1067 if (pubname_param.found) {
1068 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1074 /* Loop on CUs (Compilation Unit) */
1075 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1076 /* Get the DIE(Debugging Information Entry) of this CU */
1077 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1081 /* Check if target file is included. */
1083 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1087 if (!pp->file || pf->fname) {
1089 ret = find_probe_point_by_func(pf);
1090 else if (pp->lazy_line)
1091 ret = find_probe_point_lazy(&pf->cu_die, pf);
1094 ret = find_probe_point_by_line(pf);
1103 intlist__delete(pf->lcache);
1109 struct local_vars_finder {
1110 struct probe_finder *pf;
1111 struct perf_probe_arg *args;
1118 /* Collect available variables in this scope */
1119 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1121 struct local_vars_finder *vf = data;
1122 struct probe_finder *pf = vf->pf;
1125 tag = dwarf_tag(die_mem);
1126 if (tag == DW_TAG_formal_parameter ||
1127 (tag == DW_TAG_variable && vf->vars)) {
1128 if (convert_variable_location(die_mem, vf->pf->addr,
1129 vf->pf->fb_ops, &pf->sp_die,
1131 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1132 if (vf->args[vf->nargs].var == NULL) {
1134 return DIE_FIND_CB_END;
1136 pr_debug(" %s", vf->args[vf->nargs].var);
1141 if (dwarf_haspc(die_mem, vf->pf->addr))
1142 return DIE_FIND_CB_CONTINUE;
1144 return DIE_FIND_CB_SIBLING;
1147 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1148 struct perf_probe_arg *args)
1153 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1154 .max_args = MAX_PROBE_ARGS, .ret = 0};
1156 for (i = 0; i < pf->pev->nargs; i++) {
1157 /* var never be NULL */
1158 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1160 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1161 /* Copy normal argument */
1162 args[n] = pf->pev->args[i];
1166 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1168 /* Special local variables */
1169 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1171 pr_debug(" (%d)\n", vf.nargs - n);
1179 /* Add a found probe point into trace event list */
1180 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1182 struct trace_event_finder *tf =
1183 container_of(pf, struct trace_event_finder, pf);
1184 struct perf_probe_point *pp = &pf->pev->point;
1185 struct probe_trace_event *tev;
1186 struct perf_probe_arg *args;
1189 /* Check number of tevs */
1190 if (tf->ntevs == tf->max_tevs) {
1191 pr_warning("Too many( > %d) probe point found.\n",
1195 tev = &tf->tevs[tf->ntevs++];
1197 /* Trace point should be converted from subprogram DIE */
1198 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1199 pp->retprobe, pp->function, &tev->point);
1203 tev->point.realname = strdup(dwarf_diename(sc_die));
1204 if (!tev->point.realname)
1207 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1210 /* Expand special probe argument if exist */
1211 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1215 ret = expand_probe_args(sc_die, pf, args);
1220 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1221 if (tev->args == NULL) {
1226 /* Find each argument */
1227 for (i = 0; i < tev->nargs; i++) {
1228 pf->pvar = &args[i];
1229 pf->tvar = &tev->args[i];
1230 /* Variable should be found from scope DIE */
1231 ret = find_variable(sc_die, pf);
1241 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1242 int debuginfo__find_trace_events(struct debuginfo *dbg,
1243 struct perf_probe_event *pev,
1244 struct probe_trace_event **tevs)
1246 struct trace_event_finder tf = {
1247 .pf = {.pev = pev, .callback = add_probe_trace_event},
1248 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1251 /* Allocate result tevs array */
1252 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1259 ret = debuginfo__find_probes(dbg, &tf.pf);
1265 return (ret < 0) ? ret : tf.ntevs;
1268 /* Collect available variables in this scope */
1269 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1271 struct available_var_finder *af = data;
1272 struct variable_list *vl;
1275 vl = &af->vls[af->nvls - 1];
1277 tag = dwarf_tag(die_mem);
1278 if (tag == DW_TAG_formal_parameter ||
1279 tag == DW_TAG_variable) {
1280 ret = convert_variable_location(die_mem, af->pf.addr,
1281 af->pf.fb_ops, &af->pf.sp_die,
1283 if (ret == 0 || ret == -ERANGE) {
1285 bool externs = !af->child;
1288 strbuf_init(&buf, 64);
1290 if (probe_conf.show_location_range) {
1293 strbuf_addf(&buf, "[INV]\t");
1295 strbuf_addf(&buf, "[VAL]\t");
1297 strbuf_addf(&buf, "[EXT]\t");
1300 ret2 = die_get_varname(die_mem, &buf);
1302 if (!ret2 && probe_conf.show_location_range &&
1304 strbuf_addf(&buf, "\t");
1305 ret2 = die_get_var_range(&af->pf.sp_die,
1309 pr_debug("Add new var: %s\n", buf.buf);
1311 strlist__add(vl->vars,
1312 strbuf_detach(&buf, NULL));
1314 strbuf_release(&buf);
1318 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1319 return DIE_FIND_CB_CONTINUE;
1321 return DIE_FIND_CB_SIBLING;
1324 /* Add a found vars into available variables list */
1325 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1327 struct available_var_finder *af =
1328 container_of(pf, struct available_var_finder, pf);
1329 struct perf_probe_point *pp = &pf->pev->point;
1330 struct variable_list *vl;
1334 /* Check number of tevs */
1335 if (af->nvls == af->max_vls) {
1336 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1339 vl = &af->vls[af->nvls++];
1341 /* Trace point should be converted from subprogram DIE */
1342 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1343 pp->retprobe, pp->function, &vl->point);
1347 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1350 /* Find local variables */
1351 vl->vars = strlist__new(NULL, NULL);
1352 if (vl->vars == NULL)
1355 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1357 /* Find external variables */
1358 if (!probe_conf.show_ext_vars)
1360 /* Don't need to search child DIE for external vars. */
1362 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1365 if (strlist__empty(vl->vars)) {
1366 strlist__delete(vl->vars);
1374 * Find available variables at given probe point
1375 * Return the number of found probe points. Return 0 if there is no
1376 * matched probe point. Return <0 if an error occurs.
1378 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1379 struct perf_probe_event *pev,
1380 struct variable_list **vls)
1382 struct available_var_finder af = {
1383 .pf = {.pev = pev, .callback = add_available_vars},
1385 .max_vls = probe_conf.max_probes};
1388 /* Allocate result vls array */
1389 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1396 ret = debuginfo__find_probes(dbg, &af.pf);
1398 /* Free vlist for error */
1400 zfree(&af.vls[af.nvls].point.symbol);
1401 strlist__delete(af.vls[af.nvls].vars);
1407 return (ret < 0) ? ret : af.nvls;
1410 /* For the kernel module, we need a special code to get a DIE */
1411 static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs)
1417 GElf_Shdr mem, *shdr;
1420 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1424 /* Get the number of relocations */
1425 n = dwfl_module_relocations(dbg->mod);
1428 /* Search the relocation related .text section */
1429 for (i = 0; i < n; i++) {
1430 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1431 if (strcmp(p, ".text") == 0) {
1432 /* OK, get the section header */
1433 scn = elf_getscn(elf, shndx);
1436 shdr = gelf_getshdr(scn, &mem);
1439 *offs = shdr->sh_addr;
1445 /* Reverse search */
1446 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1447 struct perf_probe_point *ppt)
1449 Dwarf_Die cudie, spdie, indie;
1450 Dwarf_Addr _addr = 0, baseaddr = 0;
1451 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1452 int baseline = 0, lineno = 0, ret = 0;
1457 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1458 if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) {
1463 pr_warning("Failed to find debug information for address %lx\n",
1469 /* Find a corresponding line (filename and lineno) */
1470 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1471 /* Don't care whether it failed or not */
1473 /* Find a corresponding function (name, baseline and baseaddr) */
1474 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1475 /* Get function entry information */
1476 func = basefunc = dwarf_diename(&spdie);
1478 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1479 dwarf_decl_line(&spdie, &baseline) != 0) {
1484 fname = dwarf_decl_file(&spdie);
1485 if (addr == (unsigned long)baseaddr) {
1486 /* Function entry - Relative line number is 0 */
1491 /* Track down the inline functions step by step */
1492 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1494 /* There is an inline function */
1495 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1498 * addr is at an inline function entry.
1499 * In this case, lineno should be the call-site
1500 * line number. (overwrite lineinfo)
1502 lineno = die_get_call_lineno(&indie);
1503 fname = die_get_call_file(&indie);
1507 * addr is in an inline function body.
1508 * Since lineno points one of the lines
1509 * of the inline function, baseline should
1510 * be the entry line of the inline function.
1512 tmp = dwarf_diename(&indie);
1514 dwarf_decl_line(&indie, &baseline) != 0)
1520 /* Verify the lineno and baseline are in a same file */
1521 tmp = dwarf_decl_file(&spdie);
1522 if (!tmp || strcmp(tmp, fname) != 0)
1527 /* Make a relative line number or an offset */
1529 ppt->line = lineno - baseline;
1530 else if (basefunc) {
1531 ppt->offset = addr - (unsigned long)baseaddr;
1535 /* Duplicate strings */
1537 ppt->function = strdup(func);
1538 if (ppt->function == NULL) {
1544 ppt->file = strdup(fname);
1545 if (ppt->file == NULL) {
1546 zfree(&ppt->function);
1552 if (ret == 0 && (fname || func))
1553 ret = 1; /* Found a point */
1557 /* Add a line and store the src path */
1558 static int line_range_add_line(const char *src, unsigned int lineno,
1559 struct line_range *lr)
1561 /* Copy source path */
1563 lr->path = strdup(src);
1564 if (lr->path == NULL)
1567 return intlist__add(lr->line_list, lineno);
1570 static int line_range_walk_cb(const char *fname, int lineno,
1571 Dwarf_Addr addr __maybe_unused,
1574 struct line_finder *lf = data;
1577 if ((strtailcmp(fname, lf->fname) != 0) ||
1578 (lf->lno_s > lineno || lf->lno_e < lineno))
1581 err = line_range_add_line(fname, lineno, lf->lr);
1582 if (err < 0 && err != -EEXIST)
1588 /* Find line range from its line number */
1589 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1593 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1597 if (!intlist__empty(lf->lr->line_list))
1598 ret = lf->found = 1;
1600 ret = 0; /* Lines are not found */
1602 zfree(&lf->lr->path);
1607 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1609 int ret = find_line_range_by_line(in_die, data);
1612 * We have to check all instances of inlined function, because
1613 * some execution paths can be optimized out depends on the
1614 * function argument of instances. However, if an error occurs,
1615 * it should be handled by the caller.
1617 return ret < 0 ? ret : 0;
1620 /* Search function definition from function name */
1621 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1623 struct dwarf_callback_param *param = data;
1624 struct line_finder *lf = param->data;
1625 struct line_range *lr = lf->lr;
1627 /* Check declared file */
1628 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1631 if (die_is_func_def(sp_die) &&
1632 die_match_name(sp_die, lr->function)) {
1633 lf->fname = dwarf_decl_file(sp_die);
1634 dwarf_decl_line(sp_die, &lr->offset);
1635 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1636 lf->lno_s = lr->offset + lr->start;
1637 if (lf->lno_s < 0) /* Overflow */
1638 lf->lno_s = INT_MAX;
1639 lf->lno_e = lr->offset + lr->end;
1640 if (lf->lno_e < 0) /* Overflow */
1641 lf->lno_e = INT_MAX;
1642 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1643 lr->start = lf->lno_s;
1644 lr->end = lf->lno_e;
1645 if (!die_is_func_instance(sp_die))
1646 param->retval = die_walk_instances(sp_die,
1647 line_range_inline_cb, lf);
1649 param->retval = find_line_range_by_line(sp_die, lf);
1650 return DWARF_CB_ABORT;
1655 static int find_line_range_by_func(struct line_finder *lf)
1657 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1658 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1659 return param.retval;
1662 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1664 struct line_finder lf = {.lr = lr, .found = 0};
1666 Dwarf_Off off = 0, noff;
1669 const char *comp_dir;
1671 /* Fastpath: lookup by function name from .debug_pubnames section */
1673 struct pubname_callback_param pubname_param = {
1674 .function = lr->function, .file = lr->file,
1675 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1676 struct dwarf_callback_param line_range_param = {
1677 .data = (void *)&lf, .retval = 0};
1679 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1681 if (pubname_param.found) {
1682 line_range_search_cb(&lf.sp_die, &line_range_param);
1688 /* Loop on CUs (Compilation Unit) */
1689 while (!lf.found && ret >= 0) {
1690 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1691 NULL, NULL, NULL) != 0)
1694 /* Get the DIE(Debugging Information Entry) of this CU */
1695 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1699 /* Check if target file is included. */
1701 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1705 if (!lr->file || lf.fname) {
1707 ret = find_line_range_by_func(&lf);
1709 lf.lno_s = lr->start;
1711 ret = find_line_range_by_line(NULL, &lf);
1718 /* Store comp_dir */
1720 comp_dir = cu_get_comp_dir(&lf.cu_die);
1722 lr->comp_dir = strdup(comp_dir);
1728 pr_debug("path: %s\n", lr->path);
1729 return (ret < 0) ? ret : lf.found;
1733 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1734 * and chop off leading directories that do not exist. Result is passed back as
1735 * a newly allocated path on success.
1736 * Return 0 if file was found and readable, -errno otherwise.
1738 int get_real_path(const char *raw_path, const char *comp_dir,
1741 const char *prefix = symbol_conf.source_prefix;
1744 if (raw_path[0] != '/' && comp_dir)
1745 /* If not an absolute path, try to use comp_dir */
1748 if (access(raw_path, R_OK) == 0) {
1749 *new_path = strdup(raw_path);
1750 return *new_path ? 0 : -ENOMEM;
1756 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1761 sprintf(*new_path, "%s/%s", prefix, raw_path);
1763 if (access(*new_path, R_OK) == 0)
1766 if (!symbol_conf.source_prefix) {
1767 /* In case of searching comp_dir, don't retry */
1777 raw_path = strchr(++raw_path, '/');