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 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
77 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
87 memset(dbg, 0, sizeof(*dbg));
92 static struct debuginfo *__debuginfo__new(const char *path)
94 struct debuginfo *dbg = zalloc(sizeof(*dbg));
98 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
101 pr_debug("Open Debuginfo file: %s\n", path);
105 enum dso_binary_type distro_dwarf_types[] = {
106 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
107 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
108 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
109 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
110 DSO_BINARY_TYPE__NOT_FOUND,
113 struct debuginfo *debuginfo__new(const char *path)
115 enum dso_binary_type *type;
116 char buf[PATH_MAX], nil = '\0';
118 struct debuginfo *dinfo = NULL;
120 /* Try to open distro debuginfo files */
121 dso = dso__new(path);
125 for (type = distro_dwarf_types;
126 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
128 if (dso__read_binary_type_filename(dso, *type, &nil,
131 dinfo = __debuginfo__new(buf);
136 /* if failed to open all distro debuginfo, open given binary */
137 return dinfo ? : __debuginfo__new(path);
140 void debuginfo__delete(struct debuginfo *dbg)
150 * Probe finder related functions
153 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
155 struct probe_trace_arg_ref *ref;
156 ref = zalloc(sizeof(struct probe_trace_arg_ref));
163 * Convert a location into trace_arg.
164 * If tvar == NULL, this just checks variable can be converted.
165 * If fentry == true and vr_die is a parameter, do huristic search
166 * for the location fuzzed by function entry mcount.
168 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
169 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
170 struct probe_trace_arg *tvar)
172 Dwarf_Attribute attr;
182 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
185 /* TODO: handle more than 1 exprs */
186 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
187 return -EINVAL; /* Broken DIE ? */
188 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
189 ret = dwarf_entrypc(sp_die, &tmp);
190 if (ret || addr != tmp ||
191 dwarf_tag(vr_die) != DW_TAG_formal_parameter ||
192 dwarf_highpc(sp_die, &tmp))
195 * This is fuzzed by fentry mcount. We try to find the
196 * parameter location at the earliest address.
198 for (addr += 1; addr <= tmp; addr++) {
199 if (dwarf_getlocation_addr(&attr, addr, &op,
207 /* TODO: Support const_value */
210 if (op->atom == DW_OP_addr) {
214 /* Static variables on memory (not stack), make @varname */
215 ret = strlen(dwarf_diename(vr_die));
216 tvar->value = zalloc(ret + 2);
217 if (tvar->value == NULL)
219 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
220 tvar->ref = alloc_trace_arg_ref((long)offs);
221 if (tvar->ref == NULL)
226 /* If this is based on frame buffer, set the offset */
227 if (op->atom == DW_OP_fbreg) {
235 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
236 regn = op->atom - DW_OP_breg0;
239 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
240 regn = op->atom - DW_OP_reg0;
241 } else if (op->atom == DW_OP_bregx) {
245 } else if (op->atom == DW_OP_regx) {
248 pr_debug("DW_OP %x is not supported.\n", op->atom);
255 regs = get_arch_regstr(regn);
257 /* This should be a bug in DWARF or this tool */
258 pr_warning("Mapping for the register number %u "
259 "missing on this architecture.\n", regn);
263 tvar->value = strdup(regs);
264 if (tvar->value == NULL)
268 tvar->ref = alloc_trace_arg_ref((long)offs);
269 if (tvar->ref == NULL)
275 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
277 static int convert_variable_type(Dwarf_Die *vr_die,
278 struct probe_trace_arg *tvar,
281 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
284 char sbuf[STRERR_BUFSIZE];
285 int bsize, boffs, total;
288 /* TODO: check all types */
289 if (cast && strcmp(cast, "string") != 0) {
290 /* Non string type is OK */
291 tvar->type = strdup(cast);
292 return (tvar->type == NULL) ? -ENOMEM : 0;
295 bsize = dwarf_bitsize(vr_die);
297 /* This is a bitfield */
298 boffs = dwarf_bitoffset(vr_die);
299 total = dwarf_bytesize(vr_die);
300 if (boffs < 0 || total < 0)
302 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
303 BYTES_TO_BITS(total));
307 if (die_get_real_type(vr_die, &type) == NULL) {
308 pr_warning("Failed to get a type information of %s.\n",
309 dwarf_diename(vr_die));
313 pr_debug("%s type is %s.\n",
314 dwarf_diename(vr_die), dwarf_diename(&type));
316 if (cast && strcmp(cast, "string") == 0) { /* String type */
317 ret = dwarf_tag(&type);
318 if (ret != DW_TAG_pointer_type &&
319 ret != DW_TAG_array_type) {
320 pr_warning("Failed to cast into string: "
321 "%s(%s) is not a pointer nor array.\n",
322 dwarf_diename(vr_die), dwarf_diename(&type));
325 if (die_get_real_type(&type, &type) == NULL) {
326 pr_warning("Failed to get a type"
330 if (ret == DW_TAG_pointer_type) {
332 ref_ptr = &(*ref_ptr)->next;
333 /* Add new reference with offset +0 */
334 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
335 if (*ref_ptr == NULL) {
336 pr_warning("Out of memory error\n");
340 if (!die_compare_name(&type, "char") &&
341 !die_compare_name(&type, "unsigned char")) {
342 pr_warning("Failed to cast into string: "
343 "%s is not (unsigned) char *.\n",
344 dwarf_diename(vr_die));
347 tvar->type = strdup(cast);
348 return (tvar->type == NULL) ? -ENOMEM : 0;
351 ret = dwarf_bytesize(&type);
353 /* No size ... try to use default type */
355 ret = BYTES_TO_BITS(ret);
357 /* Check the bitwidth */
358 if (ret > MAX_BASIC_TYPE_BITS) {
359 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
360 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
361 ret = MAX_BASIC_TYPE_BITS;
363 ret = snprintf(buf, 16, "%c%d",
364 die_is_signed_type(&type) ? 's' : 'u', ret);
367 if (ret < 0 || ret >= 16) {
370 pr_warning("Failed to convert variable type: %s\n",
371 strerror_r(-ret, sbuf, sizeof(sbuf)));
374 tvar->type = strdup(buf);
375 if (tvar->type == NULL)
380 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
381 struct perf_probe_arg_field *field,
382 struct probe_trace_arg_ref **ref_ptr,
385 struct probe_trace_arg_ref *ref = *ref_ptr;
390 pr_debug("converting %s in %s\n", field->name, varname);
391 if (die_get_real_type(vr_die, &type) == NULL) {
392 pr_warning("Failed to get the type of %s.\n", varname);
395 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
396 tag = dwarf_tag(&type);
398 if (field->name[0] == '[' &&
399 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
401 /* Save original type for next field */
402 memcpy(die_mem, &type, sizeof(*die_mem));
403 /* Get the type of this array */
404 if (die_get_real_type(&type, &type) == NULL) {
405 pr_warning("Failed to get the type of %s.\n", varname);
408 pr_debug2("Array real type: (%x)\n",
409 (unsigned)dwarf_dieoffset(&type));
410 if (tag == DW_TAG_pointer_type) {
411 ref = zalloc(sizeof(struct probe_trace_arg_ref));
415 (*ref_ptr)->next = ref;
419 ref->offset += dwarf_bytesize(&type) * field->index;
421 /* Save vr_die for converting types */
422 memcpy(die_mem, vr_die, sizeof(*die_mem));
424 } else if (tag == DW_TAG_pointer_type) {
425 /* Check the pointer and dereference */
427 pr_err("Semantic error: %s must be referred by '->'\n",
431 /* Get the type pointed by this pointer */
432 if (die_get_real_type(&type, &type) == NULL) {
433 pr_warning("Failed to get the type of %s.\n", varname);
436 /* Verify it is a data structure */
437 tag = dwarf_tag(&type);
438 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
439 pr_warning("%s is not a data structure nor an union.\n",
444 ref = zalloc(sizeof(struct probe_trace_arg_ref));
448 (*ref_ptr)->next = ref;
452 /* Verify it is a data structure */
453 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
454 pr_warning("%s is not a data structure nor an union.\n",
458 if (field->name[0] == '[') {
459 pr_err("Semantic error: %s is not a pointer"
460 " nor array.\n", varname);
463 /* While prcessing unnamed field, we don't care about this */
464 if (field->ref && dwarf_diename(vr_die)) {
465 pr_err("Semantic error: %s must be referred by '.'\n",
470 pr_warning("Structure on a register is not "
476 if (die_find_member(&type, field->name, die_mem) == NULL) {
477 pr_warning("%s(type:%s) has no member %s.\n", varname,
478 dwarf_diename(&type), field->name);
482 /* Get the offset of the field */
483 if (tag == DW_TAG_union_type) {
486 ret = die_get_data_member_location(die_mem, &offs);
488 pr_warning("Failed to get the offset of %s.\n",
493 ref->offset += (long)offs;
495 /* If this member is unnamed, we need to reuse this field */
496 if (!dwarf_diename(die_mem))
497 return convert_variable_fields(die_mem, varname, field,
501 /* Converting next field */
503 return convert_variable_fields(die_mem, field->name,
504 field->next, &ref, die_mem);
509 /* Show a variables in kprobe event format */
510 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
515 pr_debug("Converting variable %s into trace event.\n",
516 dwarf_diename(vr_die));
518 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
519 &pf->sp_die, pf->tvar);
520 if (ret == -ENOENT || ret == -EINVAL)
521 pr_err("Failed to find the location of %s at this address.\n"
522 " Perhaps, it has been optimized out.\n", pf->pvar->var);
523 else if (ret == -ENOTSUP)
524 pr_err("Sorry, we don't support this variable location yet.\n");
525 else if (ret == 0 && pf->pvar->field) {
526 ret = convert_variable_fields(vr_die, pf->pvar->var,
527 pf->pvar->field, &pf->tvar->ref,
532 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
533 /* *expr will be cached in libdw. Don't free it. */
537 /* Find a variable in a scope DIE */
538 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
544 if (!is_c_varname(pf->pvar->var)) {
545 /* Copy raw parameters */
546 pf->tvar->value = strdup(pf->pvar->var);
547 if (pf->tvar->value == NULL)
549 if (pf->pvar->type) {
550 pf->tvar->type = strdup(pf->pvar->type);
551 if (pf->tvar->type == NULL)
554 if (pf->pvar->name) {
555 pf->tvar->name = strdup(pf->pvar->name);
556 if (pf->tvar->name == NULL)
559 pf->tvar->name = NULL;
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, 0, &vr_die))
582 pr_warning("Failed to find '%s' in this function.\n",
587 ret = convert_variable(&vr_die, pf);
592 /* Convert subprogram DIE to trace point */
593 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
594 Dwarf_Addr paddr, bool retprobe,
595 struct probe_trace_point *tp)
597 Dwarf_Addr eaddr, highaddr;
601 /* Verify the address is correct */
602 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
603 pr_warning("Failed to get entry address of %s\n",
604 dwarf_diename(sp_die));
607 if (dwarf_highpc(sp_die, &highaddr) != 0) {
608 pr_warning("Failed to get end address of %s\n",
609 dwarf_diename(sp_die));
612 if (paddr > highaddr) {
613 pr_warning("Offset specified is greater than size of %s\n",
614 dwarf_diename(sp_die));
618 symbol = dwarf_diename(sp_die);
620 /* Try to get the symbol name from symtab */
621 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
623 pr_warning("Failed to find symbol at 0x%lx\n",
624 (unsigned long)paddr);
627 eaddr = sym.st_value;
629 tp->offset = (unsigned long)(paddr - eaddr);
630 tp->address = (unsigned long)paddr;
631 tp->symbol = strdup(symbol);
635 /* Return probe must be on the head of a subprogram */
637 if (eaddr != paddr) {
638 pr_warning("Return probe must be on the head of"
639 " a real function.\n");
648 /* Call probe_finder callback with scope DIE */
649 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
651 Dwarf_Attribute fb_attr;
656 pr_err("Caller must pass a scope DIE. Program error.\n");
660 /* If not a real subprogram, find a real one */
661 if (!die_is_func_def(sc_die)) {
662 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
663 pr_warning("Failed to find probe point in any "
668 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
670 /* Get the frame base attribute/ops from subprogram */
671 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
672 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
673 if (ret <= 0 || nops == 0) {
675 #if _ELFUTILS_PREREQ(0, 142)
676 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
679 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
680 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
681 pr_warning("Failed to get call frame on 0x%jx\n",
682 (uintmax_t)pf->addr);
688 /* Call finder's callback handler */
689 ret = pf->callback(sc_die, pf);
691 /* *pf->fb_ops will be cached in libdw. Don't free it. */
697 struct find_scope_param {
698 const char *function;
706 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
708 struct find_scope_param *fsp = data;
712 /* Skip if declared file name does not match */
714 file = dwarf_decl_file(fn_die);
715 if (!file || strcmp(fsp->file, file) != 0)
718 /* If the function name is given, that's what user expects */
720 if (die_compare_name(fn_die, fsp->function)) {
721 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
726 /* With the line number, find the nearest declared DIE */
727 dwarf_decl_line(fn_die, &lno);
728 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
729 /* Keep a candidate and continue */
730 fsp->diff = fsp->line - lno;
731 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
738 /* Find an appropriate scope fits to given conditions */
739 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
741 struct find_scope_param fsp = {
742 .function = pf->pev->point.function,
750 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
752 return fsp.found ? die_mem : NULL;
755 static int probe_point_line_walker(const char *fname, int lineno,
756 Dwarf_Addr addr, void *data)
758 struct probe_finder *pf = data;
759 Dwarf_Die *sc_die, die_mem;
762 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
766 sc_die = find_best_scope(pf, &die_mem);
768 pr_warning("Failed to find scope of probe point.\n");
772 ret = call_probe_finder(sc_die, pf);
774 /* Continue if no error, because the line will be in inline function */
775 return ret < 0 ? ret : 0;
778 /* Find probe point from its line number */
779 static int find_probe_point_by_line(struct probe_finder *pf)
781 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
784 /* Find lines which match lazy pattern */
785 static int find_lazy_match_lines(struct intlist *list,
786 const char *fname, const char *pat)
792 int count = 0, linenum = 1;
793 char sbuf[STRERR_BUFSIZE];
795 fp = fopen(fname, "r");
797 pr_warning("Failed to open %s: %s\n", fname,
798 strerror_r(errno, sbuf, sizeof(sbuf)));
802 while ((len = getline(&line, &line_len, fp)) > 0) {
804 if (line[len - 1] == '\n')
805 line[len - 1] = '\0';
807 if (strlazymatch(line, pat)) {
808 intlist__add(list, linenum);
820 pr_debug("No matched lines found in %s.\n", fname);
824 static int probe_point_lazy_walker(const char *fname, int lineno,
825 Dwarf_Addr addr, void *data)
827 struct probe_finder *pf = data;
828 Dwarf_Die *sc_die, die_mem;
831 if (!intlist__has_entry(pf->lcache, lineno) ||
832 strtailcmp(fname, pf->fname) != 0)
835 pr_debug("Probe line found: line:%d addr:0x%llx\n",
836 lineno, (unsigned long long)addr);
839 sc_die = find_best_scope(pf, &die_mem);
841 pr_warning("Failed to find scope of probe point.\n");
845 ret = call_probe_finder(sc_die, pf);
848 * Continue if no error, because the lazy pattern will match
851 return ret < 0 ? ret : 0;
854 /* Find probe points from lazy pattern */
855 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
860 if (intlist__empty(pf->lcache)) {
861 const char *comp_dir;
863 comp_dir = cu_get_comp_dir(&pf->cu_die);
864 ret = get_real_path(pf->fname, comp_dir, &fpath);
866 pr_warning("Failed to find source file path.\n");
870 /* Matching lazy line pattern */
871 ret = find_lazy_match_lines(pf->lcache, fpath,
872 pf->pev->point.lazy_line);
878 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
881 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
883 struct probe_finder *pf = data;
884 struct perf_probe_point *pp = &pf->pev->point;
889 ret = find_probe_point_lazy(in_die, pf);
891 /* Get probe address */
892 if (dwarf_entrypc(in_die, &addr) != 0) {
893 pr_warning("Failed to get entry address of %s.\n",
894 dwarf_diename(in_die));
898 pf->addr += pp->offset;
899 pr_debug("found inline addr: 0x%jx\n",
900 (uintmax_t)pf->addr);
902 ret = call_probe_finder(in_die, pf);
908 /* Callback parameter with return value for libdw */
909 struct dwarf_callback_param {
914 /* Search function from function name */
915 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
917 struct dwarf_callback_param *param = data;
918 struct probe_finder *pf = param->data;
919 struct perf_probe_point *pp = &pf->pev->point;
921 /* Check tag and diename */
922 if (!die_is_func_def(sp_die) ||
923 !die_compare_name(sp_die, pp->function))
926 /* Check declared file */
927 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
930 pf->fname = dwarf_decl_file(sp_die);
931 if (pp->line) { /* Function relative line */
932 dwarf_decl_line(sp_die, &pf->lno);
934 param->retval = find_probe_point_by_line(pf);
935 } else if (die_is_func_instance(sp_die)) {
936 /* Instances always have the entry address */
937 dwarf_entrypc(sp_die, &pf->addr);
940 param->retval = find_probe_point_lazy(sp_die, pf);
942 pf->addr += pp->offset;
943 /* TODO: Check the address in this function */
944 param->retval = call_probe_finder(sp_die, pf);
947 /* Inlined function: search instances */
948 param->retval = die_walk_instances(sp_die,
949 probe_point_inline_cb, (void *)pf);
951 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
954 static int find_probe_point_by_func(struct probe_finder *pf)
956 struct dwarf_callback_param _param = {.data = (void *)pf,
958 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
959 return _param.retval;
962 struct pubname_callback_param {
970 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
972 struct pubname_callback_param *param = data;
974 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
975 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
978 if (die_compare_name(param->sp_die, param->function)) {
979 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
983 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
987 return DWARF_CB_ABORT;
994 /* Find probe points from debuginfo */
995 static int debuginfo__find_probes(struct debuginfo *dbg,
996 struct probe_finder *pf)
998 struct perf_probe_point *pp = &pf->pev->point;
1004 #if _ELFUTILS_PREREQ(0, 142)
1009 /* Get the call frame information from this dwarf */
1010 elf = dwarf_getelf(dbg->dbg);
1014 if (gelf_getehdr(elf, &ehdr) == NULL)
1017 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1018 shdr.sh_type == SHT_PROGBITS) {
1019 pf->cfi = dwarf_getcfi_elf(elf);
1021 pf->cfi = dwarf_getcfi(dbg->dbg);
1026 pf->lcache = intlist__new(NULL);
1030 /* Fastpath: lookup by function name from .debug_pubnames section */
1032 struct pubname_callback_param pubname_param = {
1033 .function = pp->function,
1035 .cu_die = &pf->cu_die,
1036 .sp_die = &pf->sp_die,
1039 struct dwarf_callback_param probe_param = {
1043 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1045 if (pubname_param.found) {
1046 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1052 /* Loop on CUs (Compilation Unit) */
1053 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1054 /* Get the DIE(Debugging Information Entry) of this CU */
1055 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1059 /* Check if target file is included. */
1061 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1065 if (!pp->file || pf->fname) {
1067 ret = find_probe_point_by_func(pf);
1068 else if (pp->lazy_line)
1069 ret = find_probe_point_lazy(&pf->cu_die, pf);
1072 ret = find_probe_point_by_line(pf);
1081 intlist__delete(pf->lcache);
1087 struct local_vars_finder {
1088 struct probe_finder *pf;
1089 struct perf_probe_arg *args;
1095 /* Collect available variables in this scope */
1096 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1098 struct local_vars_finder *vf = data;
1099 struct probe_finder *pf = vf->pf;
1102 tag = dwarf_tag(die_mem);
1103 if (tag == DW_TAG_formal_parameter ||
1104 tag == DW_TAG_variable) {
1105 if (convert_variable_location(die_mem, vf->pf->addr,
1106 vf->pf->fb_ops, &pf->sp_die,
1108 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1109 if (vf->args[vf->nargs].var == NULL) {
1111 return DIE_FIND_CB_END;
1113 pr_debug(" %s", vf->args[vf->nargs].var);
1118 if (dwarf_haspc(die_mem, vf->pf->addr))
1119 return DIE_FIND_CB_CONTINUE;
1121 return DIE_FIND_CB_SIBLING;
1124 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1125 struct perf_probe_arg *args)
1130 struct local_vars_finder vf = {.pf = pf, .args = args,
1131 .max_args = MAX_PROBE_ARGS, .ret = 0};
1133 for (i = 0; i < pf->pev->nargs; i++) {
1134 /* var never be NULL */
1135 if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
1136 pr_debug("Expanding $vars into:");
1138 /* Special local variables */
1139 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1141 pr_debug(" (%d)\n", vf.nargs - n);
1146 /* Copy normal argument */
1147 args[n] = pf->pev->args[i];
1154 /* Add a found probe point into trace event list */
1155 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1157 struct trace_event_finder *tf =
1158 container_of(pf, struct trace_event_finder, pf);
1159 struct probe_trace_event *tev;
1160 struct perf_probe_arg *args;
1163 /* Check number of tevs */
1164 if (tf->ntevs == tf->max_tevs) {
1165 pr_warning("Too many( > %d) probe point found.\n",
1169 tev = &tf->tevs[tf->ntevs++];
1171 /* Trace point should be converted from subprogram DIE */
1172 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1173 pf->pev->point.retprobe, &tev->point);
1177 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1180 /* Expand special probe argument if exist */
1181 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1185 ret = expand_probe_args(sc_die, pf, args);
1190 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1191 if (tev->args == NULL) {
1196 /* Find each argument */
1197 for (i = 0; i < tev->nargs; i++) {
1198 pf->pvar = &args[i];
1199 pf->tvar = &tev->args[i];
1200 /* Variable should be found from scope DIE */
1201 ret = find_variable(sc_die, pf);
1211 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1212 int debuginfo__find_trace_events(struct debuginfo *dbg,
1213 struct perf_probe_event *pev,
1214 struct probe_trace_event **tevs, int max_tevs)
1216 struct trace_event_finder tf = {
1217 .pf = {.pev = pev, .callback = add_probe_trace_event},
1218 .mod = dbg->mod, .max_tevs = max_tevs};
1221 /* Allocate result tevs array */
1222 *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1229 ret = debuginfo__find_probes(dbg, &tf.pf);
1235 return (ret < 0) ? ret : tf.ntevs;
1238 #define MAX_VAR_LEN 64
1240 /* Collect available variables in this scope */
1241 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1243 struct available_var_finder *af = data;
1244 struct variable_list *vl;
1245 char buf[MAX_VAR_LEN];
1248 vl = &af->vls[af->nvls - 1];
1250 tag = dwarf_tag(die_mem);
1251 if (tag == DW_TAG_formal_parameter ||
1252 tag == DW_TAG_variable) {
1253 ret = convert_variable_location(die_mem, af->pf.addr,
1254 af->pf.fb_ops, &af->pf.sp_die,
1257 ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1258 pr_debug2("Add new var: %s\n", buf);
1260 strlist__add(vl->vars, buf);
1264 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1265 return DIE_FIND_CB_CONTINUE;
1267 return DIE_FIND_CB_SIBLING;
1270 /* Add a found vars into available variables list */
1271 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1273 struct available_var_finder *af =
1274 container_of(pf, struct available_var_finder, pf);
1275 struct variable_list *vl;
1279 /* Check number of tevs */
1280 if (af->nvls == af->max_vls) {
1281 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1284 vl = &af->vls[af->nvls++];
1286 /* Trace point should be converted from subprogram DIE */
1287 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1288 pf->pev->point.retprobe, &vl->point);
1292 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1295 /* Find local variables */
1296 vl->vars = strlist__new(true, NULL);
1297 if (vl->vars == NULL)
1300 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1302 /* Find external variables */
1305 /* Don't need to search child DIE for externs. */
1307 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1310 if (strlist__empty(vl->vars)) {
1311 strlist__delete(vl->vars);
1319 * Find available variables at given probe point
1320 * Return the number of found probe points. Return 0 if there is no
1321 * matched probe point. Return <0 if an error occurs.
1323 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1324 struct perf_probe_event *pev,
1325 struct variable_list **vls,
1326 int max_vls, bool externs)
1328 struct available_var_finder af = {
1329 .pf = {.pev = pev, .callback = add_available_vars},
1331 .max_vls = max_vls, .externs = externs};
1334 /* Allocate result vls array */
1335 *vls = zalloc(sizeof(struct variable_list) * max_vls);
1342 ret = debuginfo__find_probes(dbg, &af.pf);
1344 /* Free vlist for error */
1346 zfree(&af.vls[af.nvls].point.symbol);
1347 strlist__delete(af.vls[af.nvls].vars);
1353 return (ret < 0) ? ret : af.nvls;
1356 /* Reverse search */
1357 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1358 struct perf_probe_point *ppt)
1360 Dwarf_Die cudie, spdie, indie;
1361 Dwarf_Addr _addr = 0, baseaddr = 0;
1362 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1363 int baseline = 0, lineno = 0, ret = 0;
1366 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1367 pr_warning("Failed to find debug information for address %lx\n",
1373 /* Find a corresponding line (filename and lineno) */
1374 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1375 /* Don't care whether it failed or not */
1377 /* Find a corresponding function (name, baseline and baseaddr) */
1378 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1379 /* Get function entry information */
1380 func = basefunc = dwarf_diename(&spdie);
1382 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1383 dwarf_decl_line(&spdie, &baseline) != 0) {
1388 fname = dwarf_decl_file(&spdie);
1389 if (addr == (unsigned long)baseaddr) {
1390 /* Function entry - Relative line number is 0 */
1395 /* Track down the inline functions step by step */
1396 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1398 /* There is an inline function */
1399 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1402 * addr is at an inline function entry.
1403 * In this case, lineno should be the call-site
1404 * line number. (overwrite lineinfo)
1406 lineno = die_get_call_lineno(&indie);
1407 fname = die_get_call_file(&indie);
1411 * addr is in an inline function body.
1412 * Since lineno points one of the lines
1413 * of the inline function, baseline should
1414 * be the entry line of the inline function.
1416 tmp = dwarf_diename(&indie);
1418 dwarf_decl_line(&indie, &baseline) != 0)
1424 /* Verify the lineno and baseline are in a same file */
1425 tmp = dwarf_decl_file(&spdie);
1426 if (!tmp || strcmp(tmp, fname) != 0)
1431 /* Make a relative line number or an offset */
1433 ppt->line = lineno - baseline;
1434 else if (basefunc) {
1435 ppt->offset = addr - (unsigned long)baseaddr;
1439 /* Duplicate strings */
1441 ppt->function = strdup(func);
1442 if (ppt->function == NULL) {
1448 ppt->file = strdup(fname);
1449 if (ppt->file == NULL) {
1450 zfree(&ppt->function);
1456 if (ret == 0 && (fname || func))
1457 ret = 1; /* Found a point */
1461 /* Add a line and store the src path */
1462 static int line_range_add_line(const char *src, unsigned int lineno,
1463 struct line_range *lr)
1465 /* Copy source path */
1467 lr->path = strdup(src);
1468 if (lr->path == NULL)
1471 return intlist__add(lr->line_list, lineno);
1474 static int line_range_walk_cb(const char *fname, int lineno,
1475 Dwarf_Addr addr __maybe_unused,
1478 struct line_finder *lf = data;
1481 if ((strtailcmp(fname, lf->fname) != 0) ||
1482 (lf->lno_s > lineno || lf->lno_e < lineno))
1485 err = line_range_add_line(fname, lineno, lf->lr);
1486 if (err < 0 && err != -EEXIST)
1492 /* Find line range from its line number */
1493 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1497 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1501 if (!intlist__empty(lf->lr->line_list))
1502 ret = lf->found = 1;
1504 ret = 0; /* Lines are not found */
1506 zfree(&lf->lr->path);
1511 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1513 int ret = find_line_range_by_line(in_die, data);
1516 * We have to check all instances of inlined function, because
1517 * some execution paths can be optimized out depends on the
1518 * function argument of instances. However, if an error occurs,
1519 * it should be handled by the caller.
1521 return ret < 0 ? ret : 0;
1524 /* Search function definition from function name */
1525 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1527 struct dwarf_callback_param *param = data;
1528 struct line_finder *lf = param->data;
1529 struct line_range *lr = lf->lr;
1531 /* Check declared file */
1532 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1535 if (die_is_func_def(sp_die) &&
1536 die_compare_name(sp_die, lr->function)) {
1537 lf->fname = dwarf_decl_file(sp_die);
1538 dwarf_decl_line(sp_die, &lr->offset);
1539 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1540 lf->lno_s = lr->offset + lr->start;
1541 if (lf->lno_s < 0) /* Overflow */
1542 lf->lno_s = INT_MAX;
1543 lf->lno_e = lr->offset + lr->end;
1544 if (lf->lno_e < 0) /* Overflow */
1545 lf->lno_e = INT_MAX;
1546 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1547 lr->start = lf->lno_s;
1548 lr->end = lf->lno_e;
1549 if (!die_is_func_instance(sp_die))
1550 param->retval = die_walk_instances(sp_die,
1551 line_range_inline_cb, lf);
1553 param->retval = find_line_range_by_line(sp_die, lf);
1554 return DWARF_CB_ABORT;
1559 static int find_line_range_by_func(struct line_finder *lf)
1561 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1562 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1563 return param.retval;
1566 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1568 struct line_finder lf = {.lr = lr, .found = 0};
1570 Dwarf_Off off = 0, noff;
1573 const char *comp_dir;
1575 /* Fastpath: lookup by function name from .debug_pubnames section */
1577 struct pubname_callback_param pubname_param = {
1578 .function = lr->function, .file = lr->file,
1579 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1580 struct dwarf_callback_param line_range_param = {
1581 .data = (void *)&lf, .retval = 0};
1583 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1585 if (pubname_param.found) {
1586 line_range_search_cb(&lf.sp_die, &line_range_param);
1592 /* Loop on CUs (Compilation Unit) */
1593 while (!lf.found && ret >= 0) {
1594 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1595 NULL, NULL, NULL) != 0)
1598 /* Get the DIE(Debugging Information Entry) of this CU */
1599 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1603 /* Check if target file is included. */
1605 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1609 if (!lr->file || lf.fname) {
1611 ret = find_line_range_by_func(&lf);
1613 lf.lno_s = lr->start;
1615 ret = find_line_range_by_line(NULL, &lf);
1622 /* Store comp_dir */
1624 comp_dir = cu_get_comp_dir(&lf.cu_die);
1626 lr->comp_dir = strdup(comp_dir);
1632 pr_debug("path: %s\n", lr->path);
1633 return (ret < 0) ? ret : lf.found;
1637 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1638 * and chop off leading directories that do not exist. Result is passed back as
1639 * a newly allocated path on success.
1640 * Return 0 if file was found and readable, -errno otherwise.
1642 int get_real_path(const char *raw_path, const char *comp_dir,
1645 const char *prefix = symbol_conf.source_prefix;
1648 if (raw_path[0] != '/' && comp_dir)
1649 /* If not an absolute path, try to use comp_dir */
1652 if (access(raw_path, R_OK) == 0) {
1653 *new_path = strdup(raw_path);
1654 return *new_path ? 0 : -ENOMEM;
1660 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1665 sprintf(*new_path, "%s/%s", prefix, raw_path);
1667 if (access(*new_path, R_OK) == 0)
1670 if (!symbol_conf.source_prefix) {
1671 /* In case of searching comp_dir, don't retry */
1681 raw_path = strchr(++raw_path, '/');