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 *self,
124 fd = open(path, O_RDONLY);
128 self->dwfl = dwfl_begin(&offline_callbacks);
132 mod = dwfl_report_offline(self->dwfl, "", "", fd);
136 self->dbg = dwfl_module_getdwarf(mod, &self->bias);
143 dwfl_end(self->dwfl);
146 memset(self, 0, sizeof(*self));
151 #if _ELFUTILS_PREREQ(0, 148)
152 /* This method is buggy if elfutils is older than 0.148 */
153 static int __linux_kernel_find_elf(Dwfl_Module *mod,
155 const char *module_name,
157 char **file_name, Elf **elfp)
160 const char *path = kernel_get_module_path(module_name);
162 pr_debug2("Use file %s for %s\n", path, module_name);
164 fd = open(path, O_RDONLY);
166 *file_name = strdup(path);
170 /* If failed, try to call standard method */
171 return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
175 static const Dwfl_Callbacks kernel_callbacks = {
176 .find_debuginfo = dwfl_standard_find_debuginfo,
177 .debuginfo_path = &debuginfo_path,
179 .find_elf = __linux_kernel_find_elf,
180 .section_address = dwfl_linux_kernel_module_section_address,
183 /* Get a Dwarf from live kernel image */
184 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
187 self->dwfl = dwfl_begin(&kernel_callbacks);
191 /* Load the kernel dwarves: Don't care the result here */
192 dwfl_linux_kernel_report_kernel(self->dwfl);
193 dwfl_linux_kernel_report_modules(self->dwfl);
195 self->dbg = dwfl_addrdwarf(self->dwfl, addr, &self->bias);
196 /* Here, check whether we could get a real dwarf */
198 pr_debug("Failed to find kernel dwarf at %lx\n",
199 (unsigned long)addr);
200 dwfl_end(self->dwfl);
201 memset(self, 0, sizeof(*self));
208 /* With older elfutils, this just support kernel module... */
209 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
210 Dwarf_Addr addr __maybe_unused)
212 const char *path = kernel_get_module_path("kernel");
215 pr_err("Failed to find vmlinux path\n");
219 pr_debug2("Use file %s for debuginfo\n", path);
220 return debuginfo__init_offline_dwarf(self, path);
224 struct debuginfo *debuginfo__new(const char *path)
226 struct debuginfo *self = zalloc(sizeof(struct debuginfo));
230 if (debuginfo__init_offline_dwarf(self, path) < 0) {
238 struct debuginfo *debuginfo__new_online_kernel(unsigned long addr)
240 struct debuginfo *self = zalloc(sizeof(struct debuginfo));
244 if (debuginfo__init_online_kernel_dwarf(self, (Dwarf_Addr)addr) < 0) {
252 void debuginfo__delete(struct debuginfo *self)
256 dwfl_end(self->dwfl);
262 * Probe finder related functions
265 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
267 struct probe_trace_arg_ref *ref;
268 ref = zalloc(sizeof(struct probe_trace_arg_ref));
275 * Convert a location into trace_arg.
276 * If tvar == NULL, this just checks variable can be converted.
278 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
280 struct probe_trace_arg *tvar)
282 Dwarf_Attribute attr;
291 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
294 /* TODO: handle more than 1 exprs */
295 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
296 dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
298 /* TODO: Support const_value */
302 if (op->atom == DW_OP_addr) {
306 /* Static variables on memory (not stack), make @varname */
307 ret = strlen(dwarf_diename(vr_die));
308 tvar->value = zalloc(ret + 2);
309 if (tvar->value == NULL)
311 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
312 tvar->ref = alloc_trace_arg_ref((long)offs);
313 if (tvar->ref == NULL)
318 /* If this is based on frame buffer, set the offset */
319 if (op->atom == DW_OP_fbreg) {
327 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
328 regn = op->atom - DW_OP_breg0;
331 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
332 regn = op->atom - DW_OP_reg0;
333 } else if (op->atom == DW_OP_bregx) {
337 } else if (op->atom == DW_OP_regx) {
340 pr_debug("DW_OP %x is not supported.\n", op->atom);
347 regs = get_arch_regstr(regn);
349 /* This should be a bug in DWARF or this tool */
350 pr_warning("Mapping for the register number %u "
351 "missing on this architecture.\n", regn);
355 tvar->value = strdup(regs);
356 if (tvar->value == NULL)
360 tvar->ref = alloc_trace_arg_ref((long)offs);
361 if (tvar->ref == NULL)
367 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
369 static int convert_variable_type(Dwarf_Die *vr_die,
370 struct probe_trace_arg *tvar,
373 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
376 int bsize, boffs, total;
379 /* TODO: check all types */
380 if (cast && strcmp(cast, "string") != 0) {
381 /* Non string type is OK */
382 tvar->type = strdup(cast);
383 return (tvar->type == NULL) ? -ENOMEM : 0;
386 bsize = dwarf_bitsize(vr_die);
388 /* This is a bitfield */
389 boffs = dwarf_bitoffset(vr_die);
390 total = dwarf_bytesize(vr_die);
391 if (boffs < 0 || total < 0)
393 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
394 BYTES_TO_BITS(total));
398 if (die_get_real_type(vr_die, &type) == NULL) {
399 pr_warning("Failed to get a type information of %s.\n",
400 dwarf_diename(vr_die));
404 pr_debug("%s type is %s.\n",
405 dwarf_diename(vr_die), dwarf_diename(&type));
407 if (cast && strcmp(cast, "string") == 0) { /* String type */
408 ret = dwarf_tag(&type);
409 if (ret != DW_TAG_pointer_type &&
410 ret != DW_TAG_array_type) {
411 pr_warning("Failed to cast into string: "
412 "%s(%s) is not a pointer nor array.\n",
413 dwarf_diename(vr_die), dwarf_diename(&type));
416 if (die_get_real_type(&type, &type) == NULL) {
417 pr_warning("Failed to get a type"
421 if (ret == DW_TAG_pointer_type) {
423 ref_ptr = &(*ref_ptr)->next;
424 /* Add new reference with offset +0 */
425 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
426 if (*ref_ptr == NULL) {
427 pr_warning("Out of memory error\n");
431 if (!die_compare_name(&type, "char") &&
432 !die_compare_name(&type, "unsigned char")) {
433 pr_warning("Failed to cast into string: "
434 "%s is not (unsigned) char *.\n",
435 dwarf_diename(vr_die));
438 tvar->type = strdup(cast);
439 return (tvar->type == NULL) ? -ENOMEM : 0;
442 ret = dwarf_bytesize(&type);
444 /* No size ... try to use default type */
446 ret = BYTES_TO_BITS(ret);
448 /* Check the bitwidth */
449 if (ret > MAX_BASIC_TYPE_BITS) {
450 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
451 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
452 ret = MAX_BASIC_TYPE_BITS;
454 ret = snprintf(buf, 16, "%c%d",
455 die_is_signed_type(&type) ? 's' : 'u', ret);
458 if (ret < 0 || ret >= 16) {
461 pr_warning("Failed to convert variable type: %s\n",
465 tvar->type = strdup(buf);
466 if (tvar->type == NULL)
471 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
472 struct perf_probe_arg_field *field,
473 struct probe_trace_arg_ref **ref_ptr,
476 struct probe_trace_arg_ref *ref = *ref_ptr;
481 pr_debug("converting %s in %s\n", field->name, varname);
482 if (die_get_real_type(vr_die, &type) == NULL) {
483 pr_warning("Failed to get the type of %s.\n", varname);
486 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
487 tag = dwarf_tag(&type);
489 if (field->name[0] == '[' &&
490 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
492 /* Save original type for next field */
493 memcpy(die_mem, &type, sizeof(*die_mem));
494 /* Get the type of this array */
495 if (die_get_real_type(&type, &type) == NULL) {
496 pr_warning("Failed to get the type of %s.\n", varname);
499 pr_debug2("Array real type: (%x)\n",
500 (unsigned)dwarf_dieoffset(&type));
501 if (tag == DW_TAG_pointer_type) {
502 ref = zalloc(sizeof(struct probe_trace_arg_ref));
506 (*ref_ptr)->next = ref;
510 ref->offset += dwarf_bytesize(&type) * field->index;
512 /* Save vr_die for converting types */
513 memcpy(die_mem, vr_die, sizeof(*die_mem));
515 } else if (tag == DW_TAG_pointer_type) {
516 /* Check the pointer and dereference */
518 pr_err("Semantic error: %s must be referred by '->'\n",
522 /* Get the type pointed by this pointer */
523 if (die_get_real_type(&type, &type) == NULL) {
524 pr_warning("Failed to get the type of %s.\n", varname);
527 /* Verify it is a data structure */
528 tag = dwarf_tag(&type);
529 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
530 pr_warning("%s is not a data structure nor an union.\n",
535 ref = zalloc(sizeof(struct probe_trace_arg_ref));
539 (*ref_ptr)->next = ref;
543 /* Verify it is a data structure */
544 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
545 pr_warning("%s is not a data structure nor an union.\n",
549 if (field->name[0] == '[') {
550 pr_err("Semantic error: %s is not a pointor"
551 " nor array.\n", varname);
555 pr_err("Semantic error: %s must be referred by '.'\n",
560 pr_warning("Structure on a register is not "
566 if (die_find_member(&type, field->name, die_mem) == NULL) {
567 pr_warning("%s(tyep:%s) has no member %s.\n", varname,
568 dwarf_diename(&type), field->name);
572 /* Get the offset of the field */
573 if (tag == DW_TAG_union_type) {
576 ret = die_get_data_member_location(die_mem, &offs);
578 pr_warning("Failed to get the offset of %s.\n",
583 ref->offset += (long)offs;
586 /* Converting next field */
588 return convert_variable_fields(die_mem, field->name,
589 field->next, &ref, die_mem);
594 /* Show a variables in kprobe event format */
595 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
600 pr_debug("Converting variable %s into trace event.\n",
601 dwarf_diename(vr_die));
603 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
606 pr_err("Failed to find the location of %s at this address.\n"
607 " Perhaps, it has been optimized out.\n", pf->pvar->var);
608 else if (ret == -ENOTSUP)
609 pr_err("Sorry, we don't support this variable location yet.\n");
610 else if (pf->pvar->field) {
611 ret = convert_variable_fields(vr_die, pf->pvar->var,
612 pf->pvar->field, &pf->tvar->ref,
617 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
618 /* *expr will be cached in libdw. Don't free it. */
622 /* Find a variable in a scope DIE */
623 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
629 if (!is_c_varname(pf->pvar->var)) {
630 /* Copy raw parameters */
631 pf->tvar->value = strdup(pf->pvar->var);
632 if (pf->tvar->value == NULL)
634 if (pf->pvar->type) {
635 pf->tvar->type = strdup(pf->pvar->type);
636 if (pf->tvar->type == NULL)
639 if (pf->pvar->name) {
640 pf->tvar->name = strdup(pf->pvar->name);
641 if (pf->tvar->name == NULL)
644 pf->tvar->name = NULL;
649 pf->tvar->name = strdup(pf->pvar->name);
651 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
654 ptr = strchr(buf, ':'); /* Change type separator to _ */
657 pf->tvar->name = strdup(buf);
659 if (pf->tvar->name == NULL)
662 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
663 /* Search child die for local variables and parameters. */
664 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
665 /* Search again in global variables */
666 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
670 ret = convert_variable(&vr_die, pf);
673 pr_warning("Failed to find '%s' in this function.\n",
678 /* Convert subprogram DIE to trace point */
679 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
680 bool retprobe, struct probe_trace_point *tp)
682 Dwarf_Addr eaddr, highaddr;
685 /* Copy the name of probe point */
686 name = dwarf_diename(sp_die);
688 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
689 pr_warning("Failed to get entry address of %s\n",
690 dwarf_diename(sp_die));
693 if (dwarf_highpc(sp_die, &highaddr) != 0) {
694 pr_warning("Failed to get end address of %s\n",
695 dwarf_diename(sp_die));
698 if (paddr > highaddr) {
699 pr_warning("Offset specified is greater than size of %s\n",
700 dwarf_diename(sp_die));
703 tp->symbol = strdup(name);
704 if (tp->symbol == NULL)
706 tp->offset = (unsigned long)(paddr - eaddr);
708 /* This function has no name. */
709 tp->offset = (unsigned long)paddr;
711 /* Return probe must be on the head of a subprogram */
713 if (eaddr != paddr) {
714 pr_warning("Return probe must be on the head of"
715 " a real function.\n");
724 /* Call probe_finder callback with scope DIE */
725 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
727 Dwarf_Attribute fb_attr;
732 pr_err("Caller must pass a scope DIE. Program error.\n");
736 /* If not a real subprogram, find a real one */
737 if (!die_is_func_def(sc_die)) {
738 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
739 pr_warning("Failed to find probe point in any "
744 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
746 /* Get the frame base attribute/ops from subprogram */
747 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
748 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
749 if (ret <= 0 || nops == 0) {
751 #if _ELFUTILS_PREREQ(0, 142)
752 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
755 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
756 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
757 pr_warning("Failed to get call frame on 0x%jx\n",
758 (uintmax_t)pf->addr);
764 /* Call finder's callback handler */
765 ret = pf->callback(sc_die, pf);
767 /* *pf->fb_ops will be cached in libdw. Don't free it. */
773 struct find_scope_param {
774 const char *function;
782 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
784 struct find_scope_param *fsp = data;
788 /* Skip if declared file name does not match */
790 file = dwarf_decl_file(fn_die);
791 if (!file || strcmp(fsp->file, file) != 0)
794 /* If the function name is given, that's what user expects */
796 if (die_compare_name(fn_die, fsp->function)) {
797 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
802 /* With the line number, find the nearest declared DIE */
803 dwarf_decl_line(fn_die, &lno);
804 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
805 /* Keep a candidate and continue */
806 fsp->diff = fsp->line - lno;
807 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
814 /* Find an appropriate scope fits to given conditions */
815 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
817 struct find_scope_param fsp = {
818 .function = pf->pev->point.function,
826 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
828 return fsp.found ? die_mem : NULL;
831 static int probe_point_line_walker(const char *fname, int lineno,
832 Dwarf_Addr addr, void *data)
834 struct probe_finder *pf = data;
835 Dwarf_Die *sc_die, die_mem;
838 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
842 sc_die = find_best_scope(pf, &die_mem);
844 pr_warning("Failed to find scope of probe point.\n");
848 ret = call_probe_finder(sc_die, pf);
850 /* Continue if no error, because the line will be in inline function */
851 return ret < 0 ? ret : 0;
854 /* Find probe point from its line number */
855 static int find_probe_point_by_line(struct probe_finder *pf)
857 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
860 /* Find lines which match lazy pattern */
861 static int find_lazy_match_lines(struct list_head *head,
862 const char *fname, const char *pat)
868 int count = 0, linenum = 1;
870 fp = fopen(fname, "r");
872 pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
876 while ((len = getline(&line, &line_len, fp)) > 0) {
878 if (line[len - 1] == '\n')
879 line[len - 1] = '\0';
881 if (strlazymatch(line, pat)) {
882 line_list__add_line(head, linenum);
894 pr_debug("No matched lines found in %s.\n", fname);
898 static int probe_point_lazy_walker(const char *fname, int lineno,
899 Dwarf_Addr addr, void *data)
901 struct probe_finder *pf = data;
902 Dwarf_Die *sc_die, die_mem;
905 if (!line_list__has_line(&pf->lcache, lineno) ||
906 strtailcmp(fname, pf->fname) != 0)
909 pr_debug("Probe line found: line:%d addr:0x%llx\n",
910 lineno, (unsigned long long)addr);
913 sc_die = find_best_scope(pf, &die_mem);
915 pr_warning("Failed to find scope of probe point.\n");
919 ret = call_probe_finder(sc_die, pf);
922 * Continue if no error, because the lazy pattern will match
925 return ret < 0 ? ret : 0;
928 /* Find probe points from lazy pattern */
929 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
933 if (list_empty(&pf->lcache)) {
934 /* Matching lazy line pattern */
935 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
936 pf->pev->point.lazy_line);
941 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
944 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
946 struct probe_finder *pf = data;
947 struct perf_probe_point *pp = &pf->pev->point;
952 ret = find_probe_point_lazy(in_die, pf);
954 /* Get probe address */
955 if (dwarf_entrypc(in_die, &addr) != 0) {
956 pr_warning("Failed to get entry address of %s.\n",
957 dwarf_diename(in_die));
961 pf->addr += pp->offset;
962 pr_debug("found inline addr: 0x%jx\n",
963 (uintmax_t)pf->addr);
965 ret = call_probe_finder(in_die, pf);
971 /* Callback parameter with return value for libdw */
972 struct dwarf_callback_param {
977 /* Search function from function name */
978 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
980 struct dwarf_callback_param *param = data;
981 struct probe_finder *pf = param->data;
982 struct perf_probe_point *pp = &pf->pev->point;
984 /* Check tag and diename */
985 if (!die_is_func_def(sp_die) ||
986 !die_compare_name(sp_die, pp->function))
989 /* Check declared file */
990 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
993 pf->fname = dwarf_decl_file(sp_die);
994 if (pp->line) { /* Function relative line */
995 dwarf_decl_line(sp_die, &pf->lno);
997 param->retval = find_probe_point_by_line(pf);
998 } else if (!dwarf_func_inline(sp_die)) {
1001 param->retval = find_probe_point_lazy(sp_die, pf);
1003 if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
1004 pr_warning("Failed to get entry address of "
1005 "%s.\n", dwarf_diename(sp_die));
1006 param->retval = -ENOENT;
1007 return DWARF_CB_ABORT;
1009 pf->addr += pp->offset;
1010 /* TODO: Check the address in this function */
1011 param->retval = call_probe_finder(sp_die, pf);
1014 /* Inlined function: search instances */
1015 param->retval = die_walk_instances(sp_die,
1016 probe_point_inline_cb, (void *)pf);
1018 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1021 static int find_probe_point_by_func(struct probe_finder *pf)
1023 struct dwarf_callback_param _param = {.data = (void *)pf,
1025 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1026 return _param.retval;
1029 struct pubname_callback_param {
1037 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1039 struct pubname_callback_param *param = data;
1041 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1042 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1045 if (die_compare_name(param->sp_die, param->function)) {
1046 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1050 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1054 return DWARF_CB_ABORT;
1061 /* Find probe points from debuginfo */
1062 static int debuginfo__find_probes(struct debuginfo *self,
1063 struct probe_finder *pf)
1065 struct perf_probe_point *pp = &pf->pev->point;
1066 Dwarf_Off off, noff;
1071 #if _ELFUTILS_PREREQ(0, 142)
1072 /* Get the call frame information from this dwarf */
1073 pf->cfi = dwarf_getcfi(self->dbg);
1077 line_list__init(&pf->lcache);
1079 /* Fastpath: lookup by function name from .debug_pubnames section */
1081 struct pubname_callback_param pubname_param = {
1082 .function = pp->function,
1084 .cu_die = &pf->cu_die,
1085 .sp_die = &pf->sp_die,
1088 struct dwarf_callback_param probe_param = {
1092 dwarf_getpubnames(self->dbg, pubname_search_cb,
1094 if (pubname_param.found) {
1095 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1101 /* Loop on CUs (Compilation Unit) */
1102 while (!dwarf_nextcu(self->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1103 /* Get the DIE(Debugging Information Entry) of this CU */
1104 diep = dwarf_offdie(self->dbg, off + cuhl, &pf->cu_die);
1108 /* Check if target file is included. */
1110 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1114 if (!pp->file || pf->fname) {
1116 ret = find_probe_point_by_func(pf);
1117 else if (pp->lazy_line)
1118 ret = find_probe_point_lazy(NULL, pf);
1121 ret = find_probe_point_by_line(pf);
1130 line_list__free(&pf->lcache);
1135 /* Add a found probe point into trace event list */
1136 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1138 struct trace_event_finder *tf =
1139 container_of(pf, struct trace_event_finder, pf);
1140 struct probe_trace_event *tev;
1143 /* Check number of tevs */
1144 if (tf->ntevs == tf->max_tevs) {
1145 pr_warning("Too many( > %d) probe point found.\n",
1149 tev = &tf->tevs[tf->ntevs++];
1151 /* Trace point should be converted from subprogram DIE */
1152 ret = convert_to_trace_point(&pf->sp_die, pf->addr,
1153 pf->pev->point.retprobe, &tev->point);
1157 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1160 /* Find each argument */
1161 tev->nargs = pf->pev->nargs;
1162 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1163 if (tev->args == NULL)
1165 for (i = 0; i < pf->pev->nargs; i++) {
1166 pf->pvar = &pf->pev->args[i];
1167 pf->tvar = &tev->args[i];
1168 /* Variable should be found from scope DIE */
1169 ret = find_variable(sc_die, pf);
1177 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1178 int debuginfo__find_trace_events(struct debuginfo *self,
1179 struct perf_probe_event *pev,
1180 struct probe_trace_event **tevs, int max_tevs)
1182 struct trace_event_finder tf = {
1183 .pf = {.pev = pev, .callback = add_probe_trace_event},
1184 .max_tevs = max_tevs};
1187 /* Allocate result tevs array */
1188 *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1195 ret = debuginfo__find_probes(self, &tf.pf);
1202 return (ret < 0) ? ret : tf.ntevs;
1205 #define MAX_VAR_LEN 64
1207 /* Collect available variables in this scope */
1208 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1210 struct available_var_finder *af = data;
1211 struct variable_list *vl;
1212 char buf[MAX_VAR_LEN];
1215 vl = &af->vls[af->nvls - 1];
1217 tag = dwarf_tag(die_mem);
1218 if (tag == DW_TAG_formal_parameter ||
1219 tag == DW_TAG_variable) {
1220 ret = convert_variable_location(die_mem, af->pf.addr,
1221 af->pf.fb_ops, NULL);
1223 ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1224 pr_debug2("Add new var: %s\n", buf);
1226 strlist__add(vl->vars, buf);
1230 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1231 return DIE_FIND_CB_CONTINUE;
1233 return DIE_FIND_CB_SIBLING;
1236 /* Add a found vars into available variables list */
1237 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1239 struct available_var_finder *af =
1240 container_of(pf, struct available_var_finder, pf);
1241 struct variable_list *vl;
1245 /* Check number of tevs */
1246 if (af->nvls == af->max_vls) {
1247 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1250 vl = &af->vls[af->nvls++];
1252 /* Trace point should be converted from subprogram DIE */
1253 ret = convert_to_trace_point(&pf->sp_die, pf->addr,
1254 pf->pev->point.retprobe, &vl->point);
1258 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1261 /* Find local variables */
1262 vl->vars = strlist__new(true, NULL);
1263 if (vl->vars == NULL)
1266 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1268 /* Find external variables */
1271 /* Don't need to search child DIE for externs. */
1273 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1276 if (strlist__empty(vl->vars)) {
1277 strlist__delete(vl->vars);
1284 /* Find available variables at given probe point */
1285 int debuginfo__find_available_vars_at(struct debuginfo *self,
1286 struct perf_probe_event *pev,
1287 struct variable_list **vls,
1288 int max_vls, bool externs)
1290 struct available_var_finder af = {
1291 .pf = {.pev = pev, .callback = add_available_vars},
1292 .max_vls = max_vls, .externs = externs};
1295 /* Allocate result vls array */
1296 *vls = zalloc(sizeof(struct variable_list) * max_vls);
1303 ret = debuginfo__find_probes(self, &af.pf);
1305 /* Free vlist for error */
1307 if (af.vls[af.nvls].point.symbol)
1308 free(af.vls[af.nvls].point.symbol);
1309 if (af.vls[af.nvls].vars)
1310 strlist__delete(af.vls[af.nvls].vars);
1317 return (ret < 0) ? ret : af.nvls;
1320 /* Reverse search */
1321 int debuginfo__find_probe_point(struct debuginfo *self, unsigned long addr,
1322 struct perf_probe_point *ppt)
1324 Dwarf_Die cudie, spdie, indie;
1325 Dwarf_Addr _addr, baseaddr;
1326 const char *fname = NULL, *func = NULL, *tmp;
1327 int baseline = 0, lineno = 0, ret = 0;
1329 /* Adjust address with bias */
1333 if (!dwarf_addrdie(self->dbg, (Dwarf_Addr)addr - self->bias, &cudie)) {
1334 pr_warning("Failed to find debug information for address %lx\n",
1340 /* Find a corresponding line (filename and lineno) */
1341 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1342 /* Don't care whether it failed or not */
1344 /* Find a corresponding function (name, baseline and baseaddr) */
1345 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1346 /* Get function entry information */
1347 tmp = dwarf_diename(&spdie);
1349 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1350 dwarf_decl_line(&spdie, &baseline) != 0)
1354 if (addr == (unsigned long)baseaddr)
1355 /* Function entry - Relative line number is 0 */
1357 else if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
1359 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1362 * addr is at an inline function entry.
1363 * In this case, lineno should be the call-site
1366 lineno = die_get_call_lineno(&indie);
1369 * addr is in an inline function body.
1370 * Since lineno points one of the lines
1371 * of the inline function, baseline should
1372 * be the entry line of the inline function.
1374 tmp = dwarf_diename(&indie);
1376 dwarf_decl_line(&spdie, &baseline) == 0)
1383 /* Make a relative line number or an offset */
1385 ppt->line = lineno - baseline;
1387 ppt->offset = addr - (unsigned long)baseaddr;
1389 /* Duplicate strings */
1391 ppt->function = strdup(func);
1392 if (ppt->function == NULL) {
1398 ppt->file = strdup(fname);
1399 if (ppt->file == NULL) {
1400 if (ppt->function) {
1401 free(ppt->function);
1402 ppt->function = NULL;
1409 if (ret == 0 && (fname || func))
1410 ret = 1; /* Found a point */
1414 /* Add a line and store the src path */
1415 static int line_range_add_line(const char *src, unsigned int lineno,
1416 struct line_range *lr)
1418 /* Copy source path */
1420 lr->path = strdup(src);
1421 if (lr->path == NULL)
1424 return line_list__add_line(&lr->line_list, lineno);
1427 static int line_range_walk_cb(const char *fname, int lineno,
1428 Dwarf_Addr addr __maybe_unused,
1431 struct line_finder *lf = data;
1433 if ((strtailcmp(fname, lf->fname) != 0) ||
1434 (lf->lno_s > lineno || lf->lno_e < lineno))
1437 if (line_range_add_line(fname, lineno, lf->lr) < 0)
1443 /* Find line range from its line number */
1444 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1448 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1452 if (!list_empty(&lf->lr->line_list))
1453 ret = lf->found = 1;
1455 ret = 0; /* Lines are not found */
1458 lf->lr->path = NULL;
1463 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1465 find_line_range_by_line(in_die, data);
1468 * We have to check all instances of inlined function, because
1469 * some execution paths can be optimized out depends on the
1470 * function argument of instances
1475 /* Search function definition from function name */
1476 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1478 struct dwarf_callback_param *param = data;
1479 struct line_finder *lf = param->data;
1480 struct line_range *lr = lf->lr;
1482 /* Check declared file */
1483 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1486 if (die_is_func_def(sp_die) &&
1487 die_compare_name(sp_die, lr->function)) {
1488 lf->fname = dwarf_decl_file(sp_die);
1489 dwarf_decl_line(sp_die, &lr->offset);
1490 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1491 lf->lno_s = lr->offset + lr->start;
1492 if (lf->lno_s < 0) /* Overflow */
1493 lf->lno_s = INT_MAX;
1494 lf->lno_e = lr->offset + lr->end;
1495 if (lf->lno_e < 0) /* Overflow */
1496 lf->lno_e = INT_MAX;
1497 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1498 lr->start = lf->lno_s;
1499 lr->end = lf->lno_e;
1500 if (dwarf_func_inline(sp_die))
1501 param->retval = die_walk_instances(sp_die,
1502 line_range_inline_cb, lf);
1504 param->retval = find_line_range_by_line(sp_die, lf);
1505 return DWARF_CB_ABORT;
1510 static int find_line_range_by_func(struct line_finder *lf)
1512 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1513 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1514 return param.retval;
1517 int debuginfo__find_line_range(struct debuginfo *self, struct line_range *lr)
1519 struct line_finder lf = {.lr = lr, .found = 0};
1521 Dwarf_Off off = 0, noff;
1524 const char *comp_dir;
1526 /* Fastpath: lookup by function name from .debug_pubnames section */
1528 struct pubname_callback_param pubname_param = {
1529 .function = lr->function, .file = lr->file,
1530 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1531 struct dwarf_callback_param line_range_param = {
1532 .data = (void *)&lf, .retval = 0};
1534 dwarf_getpubnames(self->dbg, pubname_search_cb,
1536 if (pubname_param.found) {
1537 line_range_search_cb(&lf.sp_die, &line_range_param);
1543 /* Loop on CUs (Compilation Unit) */
1544 while (!lf.found && ret >= 0) {
1545 if (dwarf_nextcu(self->dbg, off, &noff, &cuhl,
1546 NULL, NULL, NULL) != 0)
1549 /* Get the DIE(Debugging Information Entry) of this CU */
1550 diep = dwarf_offdie(self->dbg, off + cuhl, &lf.cu_die);
1554 /* Check if target file is included. */
1556 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1560 if (!lr->file || lf.fname) {
1562 ret = find_line_range_by_func(&lf);
1564 lf.lno_s = lr->start;
1566 ret = find_line_range_by_line(NULL, &lf);
1573 /* Store comp_dir */
1575 comp_dir = cu_get_comp_dir(&lf.cu_die);
1577 lr->comp_dir = strdup(comp_dir);
1583 pr_debug("path: %s\n", lr->path);
1584 return (ret < 0) ? ret : lf.found;