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>
33 #include <dwarf-regs.h>
35 #include <linux/bitops.h>
40 #include "probe-finder.h"
42 /* Kprobe tracer basic type is up to u64 */
43 #define MAX_BASIC_TYPE_BITS 64
45 /* Line number list operations */
47 /* Add a line to line number list */
48 static int line_list__add_line(struct list_head *head, int line)
53 /* Reverse search, because new line will be the last one */
54 list_for_each_entry_reverse(ln, head, list) {
55 if (ln->line < line) {
58 } else if (ln->line == line) /* Already exist */
61 /* List is empty, or the smallest entry */
64 pr_debug("line list: add a line %u\n", line);
65 ln = zalloc(sizeof(struct line_node));
69 INIT_LIST_HEAD(&ln->list);
70 list_add(&ln->list, p);
74 /* Check if the line in line number list */
75 static int line_list__has_line(struct list_head *head, int line)
79 /* Reverse search, because new line will be the last one */
80 list_for_each_entry(ln, head, list)
87 /* Init line number list */
88 static void line_list__init(struct list_head *head)
93 /* Free line number list */
94 static void line_list__free(struct list_head *head)
97 while (!list_empty(head)) {
98 ln = list_first_entry(head, struct line_node, list);
104 /* Dwarf FL wrappers */
105 static char *debuginfo_path; /* Currently dummy */
107 static const Dwfl_Callbacks offline_callbacks = {
108 .find_debuginfo = dwfl_standard_find_debuginfo,
109 .debuginfo_path = &debuginfo_path,
111 .section_address = dwfl_offline_section_address,
113 /* We use this table for core files too. */
114 .find_elf = dwfl_build_id_find_elf,
117 /* Get a Dwarf from offline image */
118 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
123 fd = open(path, O_RDONLY);
127 dbg->dwfl = dwfl_begin(&offline_callbacks);
131 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
135 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
145 memset(dbg, 0, sizeof(*dbg));
150 #if _ELFUTILS_PREREQ(0, 148)
151 /* This method is buggy if elfutils is older than 0.148 */
152 static int __linux_kernel_find_elf(Dwfl_Module *mod,
154 const char *module_name,
156 char **file_name, Elf **elfp)
159 const char *path = kernel_get_module_path(module_name);
161 pr_debug2("Use file %s for %s\n", path, module_name);
163 fd = open(path, O_RDONLY);
165 *file_name = strdup(path);
169 /* If failed, try to call standard method */
170 return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
174 static const Dwfl_Callbacks kernel_callbacks = {
175 .find_debuginfo = dwfl_standard_find_debuginfo,
176 .debuginfo_path = &debuginfo_path,
178 .find_elf = __linux_kernel_find_elf,
179 .section_address = dwfl_linux_kernel_module_section_address,
182 /* Get a Dwarf from live kernel image */
183 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *dbg,
186 dbg->dwfl = dwfl_begin(&kernel_callbacks);
190 /* Load the kernel dwarves: Don't care the result here */
191 dwfl_linux_kernel_report_kernel(dbg->dwfl);
192 dwfl_linux_kernel_report_modules(dbg->dwfl);
194 dbg->dbg = dwfl_addrdwarf(dbg->dwfl, addr, &dbg->bias);
195 /* Here, check whether we could get a real dwarf */
197 pr_debug("Failed to find kernel dwarf at %lx\n",
198 (unsigned long)addr);
200 memset(dbg, 0, sizeof(*dbg));
207 /* With older elfutils, this just support kernel module... */
208 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *dbg,
209 Dwarf_Addr addr __maybe_unused)
211 const char *path = kernel_get_module_path("kernel");
214 pr_err("Failed to find vmlinux path\n");
218 pr_debug2("Use file %s for debuginfo\n", path);
219 return debuginfo__init_offline_dwarf(dbg, path);
223 struct debuginfo *debuginfo__new(const char *path)
225 struct debuginfo *dbg = zalloc(sizeof(*dbg));
229 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
235 struct debuginfo *debuginfo__new_online_kernel(unsigned long addr)
237 struct debuginfo *dbg = zalloc(sizeof(*dbg));
242 if (debuginfo__init_online_kernel_dwarf(dbg, (Dwarf_Addr)addr) < 0)
248 void debuginfo__delete(struct debuginfo *dbg)
258 * Probe finder related functions
261 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
263 struct probe_trace_arg_ref *ref;
264 ref = zalloc(sizeof(struct probe_trace_arg_ref));
271 * Convert a location into trace_arg.
272 * If tvar == NULL, this just checks variable can be converted.
273 * If fentry == true and vr_die is a parameter, do huristic search
274 * for the location fuzzed by function entry mcount.
276 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
277 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
278 struct probe_trace_arg *tvar)
280 Dwarf_Attribute attr;
290 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
293 /* TODO: handle more than 1 exprs */
294 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
295 return -EINVAL; /* Broken DIE ? */
296 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
297 ret = dwarf_entrypc(sp_die, &tmp);
298 if (ret || addr != tmp ||
299 dwarf_tag(vr_die) != DW_TAG_formal_parameter ||
300 dwarf_highpc(sp_die, &tmp))
303 * This is fuzzed by fentry mcount. We try to find the
304 * parameter location at the earliest address.
306 for (addr += 1; addr <= tmp; addr++) {
307 if (dwarf_getlocation_addr(&attr, addr, &op,
315 /* TODO: Support const_value */
318 if (op->atom == DW_OP_addr) {
322 /* Static variables on memory (not stack), make @varname */
323 ret = strlen(dwarf_diename(vr_die));
324 tvar->value = zalloc(ret + 2);
325 if (tvar->value == NULL)
327 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
328 tvar->ref = alloc_trace_arg_ref((long)offs);
329 if (tvar->ref == NULL)
334 /* If this is based on frame buffer, set the offset */
335 if (op->atom == DW_OP_fbreg) {
343 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
344 regn = op->atom - DW_OP_breg0;
347 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
348 regn = op->atom - DW_OP_reg0;
349 } else if (op->atom == DW_OP_bregx) {
353 } else if (op->atom == DW_OP_regx) {
356 pr_debug("DW_OP %x is not supported.\n", op->atom);
363 regs = get_arch_regstr(regn);
365 /* This should be a bug in DWARF or this tool */
366 pr_warning("Mapping for the register number %u "
367 "missing on this architecture.\n", regn);
371 tvar->value = strdup(regs);
372 if (tvar->value == NULL)
376 tvar->ref = alloc_trace_arg_ref((long)offs);
377 if (tvar->ref == NULL)
383 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
385 static int convert_variable_type(Dwarf_Die *vr_die,
386 struct probe_trace_arg *tvar,
389 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
392 int bsize, boffs, total;
395 /* TODO: check all types */
396 if (cast && strcmp(cast, "string") != 0) {
397 /* Non string type is OK */
398 tvar->type = strdup(cast);
399 return (tvar->type == NULL) ? -ENOMEM : 0;
402 bsize = dwarf_bitsize(vr_die);
404 /* This is a bitfield */
405 boffs = dwarf_bitoffset(vr_die);
406 total = dwarf_bytesize(vr_die);
407 if (boffs < 0 || total < 0)
409 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
410 BYTES_TO_BITS(total));
414 if (die_get_real_type(vr_die, &type) == NULL) {
415 pr_warning("Failed to get a type information of %s.\n",
416 dwarf_diename(vr_die));
420 pr_debug("%s type is %s.\n",
421 dwarf_diename(vr_die), dwarf_diename(&type));
423 if (cast && strcmp(cast, "string") == 0) { /* String type */
424 ret = dwarf_tag(&type);
425 if (ret != DW_TAG_pointer_type &&
426 ret != DW_TAG_array_type) {
427 pr_warning("Failed to cast into string: "
428 "%s(%s) is not a pointer nor array.\n",
429 dwarf_diename(vr_die), dwarf_diename(&type));
432 if (die_get_real_type(&type, &type) == NULL) {
433 pr_warning("Failed to get a type"
437 if (ret == DW_TAG_pointer_type) {
439 ref_ptr = &(*ref_ptr)->next;
440 /* Add new reference with offset +0 */
441 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
442 if (*ref_ptr == NULL) {
443 pr_warning("Out of memory error\n");
447 if (!die_compare_name(&type, "char") &&
448 !die_compare_name(&type, "unsigned char")) {
449 pr_warning("Failed to cast into string: "
450 "%s is not (unsigned) char *.\n",
451 dwarf_diename(vr_die));
454 tvar->type = strdup(cast);
455 return (tvar->type == NULL) ? -ENOMEM : 0;
458 ret = dwarf_bytesize(&type);
460 /* No size ... try to use default type */
462 ret = BYTES_TO_BITS(ret);
464 /* Check the bitwidth */
465 if (ret > MAX_BASIC_TYPE_BITS) {
466 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
467 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
468 ret = MAX_BASIC_TYPE_BITS;
470 ret = snprintf(buf, 16, "%c%d",
471 die_is_signed_type(&type) ? 's' : 'u', ret);
474 if (ret < 0 || ret >= 16) {
477 pr_warning("Failed to convert variable type: %s\n",
481 tvar->type = strdup(buf);
482 if (tvar->type == NULL)
487 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
488 struct perf_probe_arg_field *field,
489 struct probe_trace_arg_ref **ref_ptr,
492 struct probe_trace_arg_ref *ref = *ref_ptr;
497 pr_debug("converting %s in %s\n", field->name, varname);
498 if (die_get_real_type(vr_die, &type) == NULL) {
499 pr_warning("Failed to get the type of %s.\n", varname);
502 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
503 tag = dwarf_tag(&type);
505 if (field->name[0] == '[' &&
506 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
508 /* Save original type for next field */
509 memcpy(die_mem, &type, sizeof(*die_mem));
510 /* Get the type of this array */
511 if (die_get_real_type(&type, &type) == NULL) {
512 pr_warning("Failed to get the type of %s.\n", varname);
515 pr_debug2("Array real type: (%x)\n",
516 (unsigned)dwarf_dieoffset(&type));
517 if (tag == DW_TAG_pointer_type) {
518 ref = zalloc(sizeof(struct probe_trace_arg_ref));
522 (*ref_ptr)->next = ref;
526 ref->offset += dwarf_bytesize(&type) * field->index;
528 /* Save vr_die for converting types */
529 memcpy(die_mem, vr_die, sizeof(*die_mem));
531 } else if (tag == DW_TAG_pointer_type) {
532 /* Check the pointer and dereference */
534 pr_err("Semantic error: %s must be referred by '->'\n",
538 /* Get the type pointed by this pointer */
539 if (die_get_real_type(&type, &type) == NULL) {
540 pr_warning("Failed to get the type of %s.\n", varname);
543 /* Verify it is a data structure */
544 tag = dwarf_tag(&type);
545 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
546 pr_warning("%s is not a data structure nor an union.\n",
551 ref = zalloc(sizeof(struct probe_trace_arg_ref));
555 (*ref_ptr)->next = ref;
559 /* Verify it is a data structure */
560 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
561 pr_warning("%s is not a data structure nor an union.\n",
565 if (field->name[0] == '[') {
566 pr_err("Semantic error: %s is not a pointor"
567 " nor array.\n", varname);
571 pr_err("Semantic error: %s must be referred by '.'\n",
576 pr_warning("Structure on a register is not "
582 if (die_find_member(&type, field->name, die_mem) == NULL) {
583 pr_warning("%s(type:%s) has no member %s.\n", varname,
584 dwarf_diename(&type), field->name);
588 /* Get the offset of the field */
589 if (tag == DW_TAG_union_type) {
592 ret = die_get_data_member_location(die_mem, &offs);
594 pr_warning("Failed to get the offset of %s.\n",
599 ref->offset += (long)offs;
602 /* Converting next field */
604 return convert_variable_fields(die_mem, field->name,
605 field->next, &ref, die_mem);
610 /* Show a variables in kprobe event format */
611 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
616 pr_debug("Converting variable %s into trace event.\n",
617 dwarf_diename(vr_die));
619 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
620 &pf->sp_die, pf->tvar);
622 pr_err("Failed to find the location of %s at this address.\n"
623 " Perhaps, it has been optimized out.\n", pf->pvar->var);
624 else if (ret == -ENOTSUP)
625 pr_err("Sorry, we don't support this variable location yet.\n");
626 else if (pf->pvar->field) {
627 ret = convert_variable_fields(vr_die, pf->pvar->var,
628 pf->pvar->field, &pf->tvar->ref,
633 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
634 /* *expr will be cached in libdw. Don't free it. */
638 /* Find a variable in a scope DIE */
639 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
645 if (!is_c_varname(pf->pvar->var)) {
646 /* Copy raw parameters */
647 pf->tvar->value = strdup(pf->pvar->var);
648 if (pf->tvar->value == NULL)
650 if (pf->pvar->type) {
651 pf->tvar->type = strdup(pf->pvar->type);
652 if (pf->tvar->type == NULL)
655 if (pf->pvar->name) {
656 pf->tvar->name = strdup(pf->pvar->name);
657 if (pf->tvar->name == NULL)
660 pf->tvar->name = NULL;
665 pf->tvar->name = strdup(pf->pvar->name);
667 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
670 ptr = strchr(buf, ':'); /* Change type separator to _ */
673 pf->tvar->name = strdup(buf);
675 if (pf->tvar->name == NULL)
678 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
679 /* Search child die for local variables and parameters. */
680 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
681 /* Search again in global variables */
682 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
686 ret = convert_variable(&vr_die, pf);
689 pr_warning("Failed to find '%s' in this function.\n",
694 /* Convert subprogram DIE to trace point */
695 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
696 Dwarf_Addr paddr, bool retprobe,
697 struct probe_trace_point *tp)
699 Dwarf_Addr eaddr, highaddr;
703 /* Verify the address is correct */
704 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
705 pr_warning("Failed to get entry address of %s\n",
706 dwarf_diename(sp_die));
709 if (dwarf_highpc(sp_die, &highaddr) != 0) {
710 pr_warning("Failed to get end address of %s\n",
711 dwarf_diename(sp_die));
714 if (paddr > highaddr) {
715 pr_warning("Offset specified is greater than size of %s\n",
716 dwarf_diename(sp_die));
720 /* Get an appropriate symbol from symtab */
721 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
723 pr_warning("Failed to find symbol at 0x%lx\n",
724 (unsigned long)paddr);
727 tp->offset = (unsigned long)(paddr - sym.st_value);
728 tp->address = (unsigned long)paddr;
729 tp->symbol = strdup(symbol);
733 /* Return probe must be on the head of a subprogram */
735 if (eaddr != paddr) {
736 pr_warning("Return probe must be on the head of"
737 " a real function.\n");
746 /* Call probe_finder callback with scope DIE */
747 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
749 Dwarf_Attribute fb_attr;
754 pr_err("Caller must pass a scope DIE. Program error.\n");
758 /* If not a real subprogram, find a real one */
759 if (!die_is_func_def(sc_die)) {
760 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
761 pr_warning("Failed to find probe point in any "
766 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
768 /* Get the frame base attribute/ops from subprogram */
769 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
770 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
771 if (ret <= 0 || nops == 0) {
773 #if _ELFUTILS_PREREQ(0, 142)
774 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
777 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
778 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
779 pr_warning("Failed to get call frame on 0x%jx\n",
780 (uintmax_t)pf->addr);
786 /* Call finder's callback handler */
787 ret = pf->callback(sc_die, pf);
789 /* *pf->fb_ops will be cached in libdw. Don't free it. */
795 struct find_scope_param {
796 const char *function;
804 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
806 struct find_scope_param *fsp = data;
810 /* Skip if declared file name does not match */
812 file = dwarf_decl_file(fn_die);
813 if (!file || strcmp(fsp->file, file) != 0)
816 /* If the function name is given, that's what user expects */
818 if (die_compare_name(fn_die, fsp->function)) {
819 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
824 /* With the line number, find the nearest declared DIE */
825 dwarf_decl_line(fn_die, &lno);
826 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
827 /* Keep a candidate and continue */
828 fsp->diff = fsp->line - lno;
829 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
836 /* Find an appropriate scope fits to given conditions */
837 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
839 struct find_scope_param fsp = {
840 .function = pf->pev->point.function,
848 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
850 return fsp.found ? die_mem : NULL;
853 static int probe_point_line_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 (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
864 sc_die = find_best_scope(pf, &die_mem);
866 pr_warning("Failed to find scope of probe point.\n");
870 ret = call_probe_finder(sc_die, pf);
872 /* Continue if no error, because the line will be in inline function */
873 return ret < 0 ? ret : 0;
876 /* Find probe point from its line number */
877 static int find_probe_point_by_line(struct probe_finder *pf)
879 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
882 /* Find lines which match lazy pattern */
883 static int find_lazy_match_lines(struct list_head *head,
884 const char *fname, const char *pat)
890 int count = 0, linenum = 1;
892 fp = fopen(fname, "r");
894 pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
898 while ((len = getline(&line, &line_len, fp)) > 0) {
900 if (line[len - 1] == '\n')
901 line[len - 1] = '\0';
903 if (strlazymatch(line, pat)) {
904 line_list__add_line(head, linenum);
916 pr_debug("No matched lines found in %s.\n", fname);
920 static int probe_point_lazy_walker(const char *fname, int lineno,
921 Dwarf_Addr addr, void *data)
923 struct probe_finder *pf = data;
924 Dwarf_Die *sc_die, die_mem;
927 if (!line_list__has_line(&pf->lcache, lineno) ||
928 strtailcmp(fname, pf->fname) != 0)
931 pr_debug("Probe line found: line:%d addr:0x%llx\n",
932 lineno, (unsigned long long)addr);
935 sc_die = find_best_scope(pf, &die_mem);
937 pr_warning("Failed to find scope of probe point.\n");
941 ret = call_probe_finder(sc_die, pf);
944 * Continue if no error, because the lazy pattern will match
947 return ret < 0 ? ret : 0;
950 /* Find probe points from lazy pattern */
951 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
955 if (list_empty(&pf->lcache)) {
956 /* Matching lazy line pattern */
957 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
958 pf->pev->point.lazy_line);
963 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
966 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
968 struct probe_finder *pf = data;
969 struct perf_probe_point *pp = &pf->pev->point;
974 ret = find_probe_point_lazy(in_die, pf);
976 /* Get probe address */
977 if (dwarf_entrypc(in_die, &addr) != 0) {
978 pr_warning("Failed to get entry address of %s.\n",
979 dwarf_diename(in_die));
983 pf->addr += pp->offset;
984 pr_debug("found inline addr: 0x%jx\n",
985 (uintmax_t)pf->addr);
987 ret = call_probe_finder(in_die, pf);
993 /* Callback parameter with return value for libdw */
994 struct dwarf_callback_param {
999 /* Search function from function name */
1000 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1002 struct dwarf_callback_param *param = data;
1003 struct probe_finder *pf = param->data;
1004 struct perf_probe_point *pp = &pf->pev->point;
1006 /* Check tag and diename */
1007 if (!die_is_func_def(sp_die) ||
1008 !die_compare_name(sp_die, pp->function))
1011 /* Check declared file */
1012 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1015 pf->fname = dwarf_decl_file(sp_die);
1016 if (pp->line) { /* Function relative line */
1017 dwarf_decl_line(sp_die, &pf->lno);
1018 pf->lno += pp->line;
1019 param->retval = find_probe_point_by_line(pf);
1020 } else if (!dwarf_func_inline(sp_die)) {
1023 param->retval = find_probe_point_lazy(sp_die, pf);
1025 if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
1026 pr_warning("Failed to get entry address of "
1027 "%s.\n", dwarf_diename(sp_die));
1028 param->retval = -ENOENT;
1029 return DWARF_CB_ABORT;
1031 pf->addr += pp->offset;
1032 /* TODO: Check the address in this function */
1033 param->retval = call_probe_finder(sp_die, pf);
1036 /* Inlined function: search instances */
1037 param->retval = die_walk_instances(sp_die,
1038 probe_point_inline_cb, (void *)pf);
1040 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1043 static int find_probe_point_by_func(struct probe_finder *pf)
1045 struct dwarf_callback_param _param = {.data = (void *)pf,
1047 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1048 return _param.retval;
1051 struct pubname_callback_param {
1059 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1061 struct pubname_callback_param *param = data;
1063 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1064 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1067 if (die_compare_name(param->sp_die, param->function)) {
1068 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1072 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1076 return DWARF_CB_ABORT;
1083 /* Find probe points from debuginfo */
1084 static int debuginfo__find_probes(struct debuginfo *dbg,
1085 struct probe_finder *pf)
1087 struct perf_probe_point *pp = &pf->pev->point;
1088 Dwarf_Off off, noff;
1093 #if _ELFUTILS_PREREQ(0, 142)
1094 /* Get the call frame information from this dwarf */
1095 pf->cfi = dwarf_getcfi(dbg->dbg);
1099 line_list__init(&pf->lcache);
1101 /* Fastpath: lookup by function name from .debug_pubnames section */
1103 struct pubname_callback_param pubname_param = {
1104 .function = pp->function,
1106 .cu_die = &pf->cu_die,
1107 .sp_die = &pf->sp_die,
1110 struct dwarf_callback_param probe_param = {
1114 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1116 if (pubname_param.found) {
1117 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1123 /* Loop on CUs (Compilation Unit) */
1124 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1125 /* Get the DIE(Debugging Information Entry) of this CU */
1126 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1130 /* Check if target file is included. */
1132 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1136 if (!pp->file || pf->fname) {
1138 ret = find_probe_point_by_func(pf);
1139 else if (pp->lazy_line)
1140 ret = find_probe_point_lazy(NULL, pf);
1143 ret = find_probe_point_by_line(pf);
1152 line_list__free(&pf->lcache);
1157 struct local_vars_finder {
1158 struct probe_finder *pf;
1159 struct perf_probe_arg *args;
1165 /* Collect available variables in this scope */
1166 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1168 struct local_vars_finder *vf = data;
1169 struct probe_finder *pf = vf->pf;
1172 tag = dwarf_tag(die_mem);
1173 if (tag == DW_TAG_formal_parameter ||
1174 tag == DW_TAG_variable) {
1175 if (convert_variable_location(die_mem, vf->pf->addr,
1176 vf->pf->fb_ops, &pf->sp_die,
1178 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1179 if (vf->args[vf->nargs].var == NULL) {
1181 return DIE_FIND_CB_END;
1183 pr_debug(" %s", vf->args[vf->nargs].var);
1188 if (dwarf_haspc(die_mem, vf->pf->addr))
1189 return DIE_FIND_CB_CONTINUE;
1191 return DIE_FIND_CB_SIBLING;
1194 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1195 struct perf_probe_arg *args)
1200 struct local_vars_finder vf = {.pf = pf, .args = args,
1201 .max_args = MAX_PROBE_ARGS, .ret = 0};
1203 for (i = 0; i < pf->pev->nargs; i++) {
1204 /* var never be NULL */
1205 if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
1206 pr_debug("Expanding $vars into:");
1208 /* Special local variables */
1209 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1211 pr_debug(" (%d)\n", vf.nargs - n);
1216 /* Copy normal argument */
1217 args[n] = pf->pev->args[i];
1224 /* Add a found probe point into trace event list */
1225 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1227 struct trace_event_finder *tf =
1228 container_of(pf, struct trace_event_finder, pf);
1229 struct probe_trace_event *tev;
1230 struct perf_probe_arg *args;
1233 /* Check number of tevs */
1234 if (tf->ntevs == tf->max_tevs) {
1235 pr_warning("Too many( > %d) probe point found.\n",
1239 tev = &tf->tevs[tf->ntevs++];
1241 /* Trace point should be converted from subprogram DIE */
1242 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1243 pf->pev->point.retprobe, &tev->point);
1247 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1250 /* Expand special probe argument if exist */
1251 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1255 ret = expand_probe_args(sc_die, pf, args);
1260 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1261 if (tev->args == NULL) {
1266 /* Find each argument */
1267 for (i = 0; i < tev->nargs; i++) {
1268 pf->pvar = &args[i];
1269 pf->tvar = &tev->args[i];
1270 /* Variable should be found from scope DIE */
1271 ret = find_variable(sc_die, pf);
1281 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1282 int debuginfo__find_trace_events(struct debuginfo *dbg,
1283 struct perf_probe_event *pev,
1284 struct probe_trace_event **tevs, int max_tevs)
1286 struct trace_event_finder tf = {
1287 .pf = {.pev = pev, .callback = add_probe_trace_event},
1288 .mod = dbg->mod, .max_tevs = max_tevs};
1291 /* Allocate result tevs array */
1292 *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1299 ret = debuginfo__find_probes(dbg, &tf.pf);
1305 return (ret < 0) ? ret : tf.ntevs;
1308 #define MAX_VAR_LEN 64
1310 /* Collect available variables in this scope */
1311 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1313 struct available_var_finder *af = data;
1314 struct variable_list *vl;
1315 char buf[MAX_VAR_LEN];
1318 vl = &af->vls[af->nvls - 1];
1320 tag = dwarf_tag(die_mem);
1321 if (tag == DW_TAG_formal_parameter ||
1322 tag == DW_TAG_variable) {
1323 ret = convert_variable_location(die_mem, af->pf.addr,
1324 af->pf.fb_ops, &af->pf.sp_die,
1327 ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1328 pr_debug2("Add new var: %s\n", buf);
1330 strlist__add(vl->vars, buf);
1334 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1335 return DIE_FIND_CB_CONTINUE;
1337 return DIE_FIND_CB_SIBLING;
1340 /* Add a found vars into available variables list */
1341 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1343 struct available_var_finder *af =
1344 container_of(pf, struct available_var_finder, pf);
1345 struct variable_list *vl;
1349 /* Check number of tevs */
1350 if (af->nvls == af->max_vls) {
1351 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1354 vl = &af->vls[af->nvls++];
1356 /* Trace point should be converted from subprogram DIE */
1357 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1358 pf->pev->point.retprobe, &vl->point);
1362 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1365 /* Find local variables */
1366 vl->vars = strlist__new(true, NULL);
1367 if (vl->vars == NULL)
1370 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1372 /* Find external variables */
1375 /* Don't need to search child DIE for externs. */
1377 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1380 if (strlist__empty(vl->vars)) {
1381 strlist__delete(vl->vars);
1388 /* Find available variables at given probe point */
1389 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1390 struct perf_probe_event *pev,
1391 struct variable_list **vls,
1392 int max_vls, bool externs)
1394 struct available_var_finder af = {
1395 .pf = {.pev = pev, .callback = add_available_vars},
1397 .max_vls = max_vls, .externs = externs};
1400 /* Allocate result vls array */
1401 *vls = zalloc(sizeof(struct variable_list) * max_vls);
1408 ret = debuginfo__find_probes(dbg, &af.pf);
1410 /* Free vlist for error */
1412 free(af.vls[af.nvls].point.symbol);
1413 strlist__delete(af.vls[af.nvls].vars);
1419 return (ret < 0) ? ret : af.nvls;
1422 /* Reverse search */
1423 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1424 struct perf_probe_point *ppt)
1426 Dwarf_Die cudie, spdie, indie;
1427 Dwarf_Addr _addr = 0, baseaddr = 0;
1428 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1429 int baseline = 0, lineno = 0, ret = 0;
1431 /* Adjust address with bias */
1435 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr - dbg->bias, &cudie)) {
1436 pr_warning("Failed to find debug information for address %lx\n",
1442 /* Find a corresponding line (filename and lineno) */
1443 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1444 /* Don't care whether it failed or not */
1446 /* Find a corresponding function (name, baseline and baseaddr) */
1447 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1448 /* Get function entry information */
1449 func = basefunc = dwarf_diename(&spdie);
1451 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1452 dwarf_decl_line(&spdie, &baseline) != 0) {
1457 fname = dwarf_decl_file(&spdie);
1458 if (addr == (unsigned long)baseaddr) {
1459 /* Function entry - Relative line number is 0 */
1464 /* Track down the inline functions step by step */
1465 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1467 /* There is an inline function */
1468 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1471 * addr is at an inline function entry.
1472 * In this case, lineno should be the call-site
1473 * line number. (overwrite lineinfo)
1475 lineno = die_get_call_lineno(&indie);
1476 fname = die_get_call_file(&indie);
1480 * addr is in an inline function body.
1481 * Since lineno points one of the lines
1482 * of the inline function, baseline should
1483 * be the entry line of the inline function.
1485 tmp = dwarf_diename(&indie);
1487 dwarf_decl_line(&indie, &baseline) != 0)
1493 /* Verify the lineno and baseline are in a same file */
1494 tmp = dwarf_decl_file(&spdie);
1495 if (!tmp || strcmp(tmp, fname) != 0)
1500 /* Make a relative line number or an offset */
1502 ppt->line = lineno - baseline;
1503 else if (basefunc) {
1504 ppt->offset = addr - (unsigned long)baseaddr;
1508 /* Duplicate strings */
1510 ppt->function = strdup(func);
1511 if (ppt->function == NULL) {
1517 ppt->file = strdup(fname);
1518 if (ppt->file == NULL) {
1519 zfree(&ppt->function);
1525 if (ret == 0 && (fname || func))
1526 ret = 1; /* Found a point */
1530 /* Add a line and store the src path */
1531 static int line_range_add_line(const char *src, unsigned int lineno,
1532 struct line_range *lr)
1534 /* Copy source path */
1536 lr->path = strdup(src);
1537 if (lr->path == NULL)
1540 return line_list__add_line(&lr->line_list, lineno);
1543 static int line_range_walk_cb(const char *fname, int lineno,
1544 Dwarf_Addr addr __maybe_unused,
1547 struct line_finder *lf = data;
1549 if ((strtailcmp(fname, lf->fname) != 0) ||
1550 (lf->lno_s > lineno || lf->lno_e < lineno))
1553 if (line_range_add_line(fname, lineno, lf->lr) < 0)
1559 /* Find line range from its line number */
1560 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1564 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1568 if (!list_empty(&lf->lr->line_list))
1569 ret = lf->found = 1;
1571 ret = 0; /* Lines are not found */
1573 zfree(&lf->lr->path);
1578 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1580 find_line_range_by_line(in_die, data);
1583 * We have to check all instances of inlined function, because
1584 * some execution paths can be optimized out depends on the
1585 * function argument of instances
1590 /* Search function definition from function name */
1591 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1593 struct dwarf_callback_param *param = data;
1594 struct line_finder *lf = param->data;
1595 struct line_range *lr = lf->lr;
1597 /* Check declared file */
1598 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1601 if (die_is_func_def(sp_die) &&
1602 die_compare_name(sp_die, lr->function)) {
1603 lf->fname = dwarf_decl_file(sp_die);
1604 dwarf_decl_line(sp_die, &lr->offset);
1605 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1606 lf->lno_s = lr->offset + lr->start;
1607 if (lf->lno_s < 0) /* Overflow */
1608 lf->lno_s = INT_MAX;
1609 lf->lno_e = lr->offset + lr->end;
1610 if (lf->lno_e < 0) /* Overflow */
1611 lf->lno_e = INT_MAX;
1612 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1613 lr->start = lf->lno_s;
1614 lr->end = lf->lno_e;
1615 if (dwarf_func_inline(sp_die))
1616 param->retval = die_walk_instances(sp_die,
1617 line_range_inline_cb, lf);
1619 param->retval = find_line_range_by_line(sp_die, lf);
1620 return DWARF_CB_ABORT;
1625 static int find_line_range_by_func(struct line_finder *lf)
1627 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1628 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1629 return param.retval;
1632 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1634 struct line_finder lf = {.lr = lr, .found = 0};
1636 Dwarf_Off off = 0, noff;
1639 const char *comp_dir;
1641 /* Fastpath: lookup by function name from .debug_pubnames section */
1643 struct pubname_callback_param pubname_param = {
1644 .function = lr->function, .file = lr->file,
1645 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1646 struct dwarf_callback_param line_range_param = {
1647 .data = (void *)&lf, .retval = 0};
1649 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1651 if (pubname_param.found) {
1652 line_range_search_cb(&lf.sp_die, &line_range_param);
1658 /* Loop on CUs (Compilation Unit) */
1659 while (!lf.found && ret >= 0) {
1660 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1661 NULL, NULL, NULL) != 0)
1664 /* Get the DIE(Debugging Information Entry) of this CU */
1665 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1669 /* Check if target file is included. */
1671 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1675 if (!lr->file || lf.fname) {
1677 ret = find_line_range_by_func(&lf);
1679 lf.lno_s = lr->start;
1681 ret = find_line_range_by_line(NULL, &lf);
1688 /* Store comp_dir */
1690 comp_dir = cu_get_comp_dir(&lf.cu_die);
1692 lr->comp_dir = strdup(comp_dir);
1698 pr_debug("path: %s\n", lr->path);
1699 return (ret < 0) ? ret : lf.found;