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>
34 #include <dwarf-regs.h>
36 #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 /* Line number list operations */
48 /* Add a line to line number list */
49 static int line_list__add_line(struct list_head *head, int line)
54 /* Reverse search, because new line will be the last one */
55 list_for_each_entry_reverse(ln, head, list) {
56 if (ln->line < line) {
59 } else if (ln->line == line) /* Already exist */
62 /* List is empty, or the smallest entry */
65 pr_debug("line list: add a line %u\n", line);
66 ln = zalloc(sizeof(struct line_node));
70 INIT_LIST_HEAD(&ln->list);
71 list_add(&ln->list, p);
75 /* Check if the line in line number list */
76 static int line_list__has_line(struct list_head *head, int line)
80 /* Reverse search, because new line will be the last one */
81 list_for_each_entry(ln, head, list)
88 /* Init line number list */
89 static void line_list__init(struct list_head *head)
94 /* Free line number list */
95 static void line_list__free(struct list_head *head)
98 while (!list_empty(head)) {
99 ln = list_first_entry(head, struct line_node, list);
105 /* Dwarf FL wrappers */
106 static char *debuginfo_path; /* Currently dummy */
108 static const Dwfl_Callbacks offline_callbacks = {
109 .find_debuginfo = dwfl_standard_find_debuginfo,
110 .debuginfo_path = &debuginfo_path,
112 .section_address = dwfl_offline_section_address,
114 /* We use this table for core files too. */
115 .find_elf = dwfl_build_id_find_elf,
118 /* Get a Dwarf from offline image */
119 static int debuginfo__init_offline_dwarf(struct debuginfo *self,
125 fd = open(path, O_RDONLY);
129 self->dwfl = dwfl_begin(&offline_callbacks);
133 mod = dwfl_report_offline(self->dwfl, "", "", fd);
137 self->dbg = dwfl_module_getdwarf(mod, &self->bias);
144 dwfl_end(self->dwfl);
147 memset(self, 0, sizeof(*self));
152 #if _ELFUTILS_PREREQ(0, 148)
153 /* This method is buggy if elfutils is older than 0.148 */
154 static int __linux_kernel_find_elf(Dwfl_Module *mod,
156 const char *module_name,
158 char **file_name, Elf **elfp)
161 const char *path = kernel_get_module_path(module_name);
163 pr_debug2("Use file %s for %s\n", path, module_name);
165 fd = open(path, O_RDONLY);
167 *file_name = strdup(path);
171 /* If failed, try to call standard method */
172 return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
176 static const Dwfl_Callbacks kernel_callbacks = {
177 .find_debuginfo = dwfl_standard_find_debuginfo,
178 .debuginfo_path = &debuginfo_path,
180 .find_elf = __linux_kernel_find_elf,
181 .section_address = dwfl_linux_kernel_module_section_address,
184 /* Get a Dwarf from live kernel image */
185 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
188 self->dwfl = dwfl_begin(&kernel_callbacks);
192 /* Load the kernel dwarves: Don't care the result here */
193 dwfl_linux_kernel_report_kernel(self->dwfl);
194 dwfl_linux_kernel_report_modules(self->dwfl);
196 self->dbg = dwfl_addrdwarf(self->dwfl, addr, &self->bias);
197 /* Here, check whether we could get a real dwarf */
199 pr_debug("Failed to find kernel dwarf at %lx\n",
200 (unsigned long)addr);
201 dwfl_end(self->dwfl);
202 memset(self, 0, sizeof(*self));
209 /* With older elfutils, this just support kernel module... */
210 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
211 Dwarf_Addr addr __used)
213 const char *path = kernel_get_module_path("kernel");
216 pr_err("Failed to find vmlinux path\n");
220 pr_debug2("Use file %s for debuginfo\n", path);
221 return debuginfo__init_offline_dwarf(self, path);
225 struct debuginfo *debuginfo__new(const char *path)
227 struct debuginfo *self = zalloc(sizeof(struct debuginfo));
231 if (debuginfo__init_offline_dwarf(self, path) < 0) {
239 struct debuginfo *debuginfo__new_online_kernel(unsigned long addr)
241 struct debuginfo *self = zalloc(sizeof(struct debuginfo));
245 if (debuginfo__init_online_kernel_dwarf(self, (Dwarf_Addr)addr) < 0) {
253 void debuginfo__delete(struct debuginfo *self)
257 dwfl_end(self->dwfl);
263 * Probe finder related functions
266 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
268 struct probe_trace_arg_ref *ref;
269 ref = zalloc(sizeof(struct probe_trace_arg_ref));
276 * Convert a location into trace_arg.
277 * If tvar == NULL, this just checks variable can be converted.
279 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
281 struct probe_trace_arg *tvar)
283 Dwarf_Attribute attr;
292 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
295 /* TODO: handle more than 1 exprs */
296 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
297 dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
299 /* TODO: Support const_value */
303 if (op->atom == DW_OP_addr) {
307 /* Static variables on memory (not stack), make @varname */
308 ret = strlen(dwarf_diename(vr_die));
309 tvar->value = zalloc(ret + 2);
310 if (tvar->value == NULL)
312 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
313 tvar->ref = alloc_trace_arg_ref((long)offs);
314 if (tvar->ref == NULL)
319 /* If this is based on frame buffer, set the offset */
320 if (op->atom == DW_OP_fbreg) {
328 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
329 regn = op->atom - DW_OP_breg0;
332 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
333 regn = op->atom - DW_OP_reg0;
334 } else if (op->atom == DW_OP_bregx) {
338 } else if (op->atom == DW_OP_regx) {
341 pr_debug("DW_OP %x is not supported.\n", op->atom);
348 regs = get_arch_regstr(regn);
350 /* This should be a bug in DWARF or this tool */
351 pr_warning("Mapping for the register number %u "
352 "missing on this architecture.\n", regn);
356 tvar->value = strdup(regs);
357 if (tvar->value == NULL)
361 tvar->ref = alloc_trace_arg_ref((long)offs);
362 if (tvar->ref == NULL)
368 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
370 static int convert_variable_type(Dwarf_Die *vr_die,
371 struct probe_trace_arg *tvar,
374 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
377 int bsize, boffs, total;
380 /* TODO: check all types */
381 if (cast && strcmp(cast, "string") != 0) {
382 /* Non string type is OK */
383 tvar->type = strdup(cast);
384 return (tvar->type == NULL) ? -ENOMEM : 0;
387 bsize = dwarf_bitsize(vr_die);
389 /* This is a bitfield */
390 boffs = dwarf_bitoffset(vr_die);
391 total = dwarf_bytesize(vr_die);
392 if (boffs < 0 || total < 0)
394 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
395 BYTES_TO_BITS(total));
399 if (die_get_real_type(vr_die, &type) == NULL) {
400 pr_warning("Failed to get a type information of %s.\n",
401 dwarf_diename(vr_die));
405 pr_debug("%s type is %s.\n",
406 dwarf_diename(vr_die), dwarf_diename(&type));
408 if (cast && strcmp(cast, "string") == 0) { /* String type */
409 ret = dwarf_tag(&type);
410 if (ret != DW_TAG_pointer_type &&
411 ret != DW_TAG_array_type) {
412 pr_warning("Failed to cast into string: "
413 "%s(%s) is not a pointer nor array.\n",
414 dwarf_diename(vr_die), dwarf_diename(&type));
417 if (ret == DW_TAG_pointer_type) {
418 if (die_get_real_type(&type, &type) == NULL) {
419 pr_warning("Failed to get a type"
424 ref_ptr = &(*ref_ptr)->next;
425 /* Add new reference with offset +0 */
426 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
427 if (*ref_ptr == NULL) {
428 pr_warning("Out of memory error\n");
432 if (!die_compare_name(&type, "char") &&
433 !die_compare_name(&type, "unsigned char")) {
434 pr_warning("Failed to cast into string: "
435 "%s is not (unsigned) char *.\n",
436 dwarf_diename(vr_die));
439 tvar->type = strdup(cast);
440 return (tvar->type == NULL) ? -ENOMEM : 0;
443 ret = dwarf_bytesize(&type);
445 /* No size ... try to use default type */
447 ret = BYTES_TO_BITS(ret);
449 /* Check the bitwidth */
450 if (ret > MAX_BASIC_TYPE_BITS) {
451 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
452 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
453 ret = MAX_BASIC_TYPE_BITS;
455 ret = snprintf(buf, 16, "%c%d",
456 die_is_signed_type(&type) ? 's' : 'u', ret);
459 if (ret < 0 || ret >= 16) {
462 pr_warning("Failed to convert variable type: %s\n",
466 tvar->type = strdup(buf);
467 if (tvar->type == NULL)
472 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
473 struct perf_probe_arg_field *field,
474 struct probe_trace_arg_ref **ref_ptr,
477 struct probe_trace_arg_ref *ref = *ref_ptr;
482 pr_debug("converting %s in %s\n", field->name, varname);
483 if (die_get_real_type(vr_die, &type) == NULL) {
484 pr_warning("Failed to get the type of %s.\n", varname);
487 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
488 tag = dwarf_tag(&type);
490 if (field->name[0] == '[' &&
491 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
493 /* Save original type for next field */
494 memcpy(die_mem, &type, sizeof(*die_mem));
495 /* Get the type of this array */
496 if (die_get_real_type(&type, &type) == NULL) {
497 pr_warning("Failed to get the type of %s.\n", varname);
500 pr_debug2("Array real type: (%x)\n",
501 (unsigned)dwarf_dieoffset(&type));
502 if (tag == DW_TAG_pointer_type) {
503 ref = zalloc(sizeof(struct probe_trace_arg_ref));
507 (*ref_ptr)->next = ref;
511 ref->offset += dwarf_bytesize(&type) * field->index;
513 /* Save vr_die for converting types */
514 memcpy(die_mem, vr_die, sizeof(*die_mem));
516 } else if (tag == DW_TAG_pointer_type) {
517 /* Check the pointer and dereference */
519 pr_err("Semantic error: %s must be referred by '->'\n",
523 /* Get the type pointed by this pointer */
524 if (die_get_real_type(&type, &type) == NULL) {
525 pr_warning("Failed to get the type of %s.\n", varname);
528 /* Verify it is a data structure */
529 if (dwarf_tag(&type) != DW_TAG_structure_type) {
530 pr_warning("%s is not a data structure.\n", varname);
534 ref = zalloc(sizeof(struct probe_trace_arg_ref));
538 (*ref_ptr)->next = ref;
542 /* Verify it is a data structure */
543 if (tag != DW_TAG_structure_type) {
544 pr_warning("%s is not a data structure.\n", varname);
547 if (field->name[0] == '[') {
548 pr_err("Semantic error: %s is not a pointor"
549 " nor array.\n", varname);
553 pr_err("Semantic error: %s must be referred by '.'\n",
558 pr_warning("Structure on a register is not "
564 if (die_find_member(&type, field->name, die_mem) == NULL) {
565 pr_warning("%s(tyep:%s) has no member %s.\n", varname,
566 dwarf_diename(&type), field->name);
570 /* Get the offset of the field */
571 ret = die_get_data_member_location(die_mem, &offs);
573 pr_warning("Failed to get the offset of %s.\n", field->name);
576 ref->offset += (long)offs;
579 /* Converting next field */
581 return convert_variable_fields(die_mem, field->name,
582 field->next, &ref, die_mem);
587 /* Show a variables in kprobe event format */
588 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
593 pr_debug("Converting variable %s into trace event.\n",
594 dwarf_diename(vr_die));
596 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
599 pr_err("Failed to find the location of %s at this address.\n"
600 " Perhaps, it has been optimized out.\n", pf->pvar->var);
601 else if (ret == -ENOTSUP)
602 pr_err("Sorry, we don't support this variable location yet.\n");
603 else if (pf->pvar->field) {
604 ret = convert_variable_fields(vr_die, pf->pvar->var,
605 pf->pvar->field, &pf->tvar->ref,
610 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
611 /* *expr will be cached in libdw. Don't free it. */
615 /* Find a variable in a scope DIE */
616 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
622 if (!is_c_varname(pf->pvar->var)) {
623 /* Copy raw parameters */
624 pf->tvar->value = strdup(pf->pvar->var);
625 if (pf->tvar->value == NULL)
627 if (pf->pvar->type) {
628 pf->tvar->type = strdup(pf->pvar->type);
629 if (pf->tvar->type == NULL)
632 if (pf->pvar->name) {
633 pf->tvar->name = strdup(pf->pvar->name);
634 if (pf->tvar->name == NULL)
637 pf->tvar->name = NULL;
642 pf->tvar->name = strdup(pf->pvar->name);
644 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
647 ptr = strchr(buf, ':'); /* Change type separator to _ */
650 pf->tvar->name = strdup(buf);
652 if (pf->tvar->name == NULL)
655 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
656 /* Search child die for local variables and parameters. */
657 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
658 /* Search again in global variables */
659 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
663 ret = convert_variable(&vr_die, pf);
666 pr_warning("Failed to find '%s' in this function.\n",
671 /* Convert subprogram DIE to trace point */
672 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
673 bool retprobe, struct probe_trace_point *tp)
678 /* Copy the name of probe point */
679 name = dwarf_diename(sp_die);
681 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
682 pr_warning("Failed to get entry address of %s\n",
683 dwarf_diename(sp_die));
686 tp->symbol = strdup(name);
687 if (tp->symbol == NULL)
689 tp->offset = (unsigned long)(paddr - eaddr);
691 /* This function has no name. */
692 tp->offset = (unsigned long)paddr;
694 /* Return probe must be on the head of a subprogram */
696 if (eaddr != paddr) {
697 pr_warning("Return probe must be on the head of"
698 " a real function.\n");
707 /* Call probe_finder callback with scope DIE */
708 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
710 Dwarf_Attribute fb_attr;
715 pr_err("Caller must pass a scope DIE. Program error.\n");
719 /* If not a real subprogram, find a real one */
720 if (dwarf_tag(sc_die) != DW_TAG_subprogram) {
721 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
722 pr_warning("Failed to find probe point in any "
727 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
729 /* Get the frame base attribute/ops from subprogram */
730 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
731 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
732 if (ret <= 0 || nops == 0) {
734 #if _ELFUTILS_PREREQ(0, 142)
735 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
738 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
739 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
740 pr_warning("Failed to get call frame on 0x%jx\n",
741 (uintmax_t)pf->addr);
747 /* Call finder's callback handler */
748 ret = pf->callback(sc_die, pf);
750 /* *pf->fb_ops will be cached in libdw. Don't free it. */
756 struct find_scope_param {
757 const char *function;
765 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
767 struct find_scope_param *fsp = data;
771 /* Skip if declared file name does not match */
773 file = dwarf_decl_file(fn_die);
774 if (!file || strcmp(fsp->file, file) != 0)
777 /* If the function name is given, that's what user expects */
779 if (die_compare_name(fn_die, fsp->function)) {
780 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
785 /* With the line number, find the nearest declared DIE */
786 dwarf_decl_line(fn_die, &lno);
787 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
788 /* Keep a candidate and continue */
789 fsp->diff = fsp->line - lno;
790 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
797 /* Find an appropriate scope fits to given conditions */
798 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
800 struct find_scope_param fsp = {
801 .function = pf->pev->point.function,
809 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
811 return fsp.found ? die_mem : NULL;
814 static int probe_point_line_walker(const char *fname, int lineno,
815 Dwarf_Addr addr, void *data)
817 struct probe_finder *pf = data;
818 Dwarf_Die *sc_die, die_mem;
821 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
825 sc_die = find_best_scope(pf, &die_mem);
827 pr_warning("Failed to find scope of probe point.\n");
831 ret = call_probe_finder(sc_die, pf);
833 /* Continue if no error, because the line will be in inline function */
834 return ret < 0 ? ret : 0;
837 /* Find probe point from its line number */
838 static int find_probe_point_by_line(struct probe_finder *pf)
840 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
843 /* Find lines which match lazy pattern */
844 static int find_lazy_match_lines(struct list_head *head,
845 const char *fname, const char *pat)
851 int count = 0, linenum = 1;
853 fp = fopen(fname, "r");
855 pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
859 while ((len = getline(&line, &line_len, fp)) > 0) {
861 if (line[len - 1] == '\n')
862 line[len - 1] = '\0';
864 if (strlazymatch(line, pat)) {
865 line_list__add_line(head, linenum);
877 pr_debug("No matched lines found in %s.\n", fname);
881 static int probe_point_lazy_walker(const char *fname, int lineno,
882 Dwarf_Addr addr, void *data)
884 struct probe_finder *pf = data;
885 Dwarf_Die *sc_die, die_mem;
888 if (!line_list__has_line(&pf->lcache, lineno) ||
889 strtailcmp(fname, pf->fname) != 0)
892 pr_debug("Probe line found: line:%d addr:0x%llx\n",
893 lineno, (unsigned long long)addr);
896 sc_die = find_best_scope(pf, &die_mem);
898 pr_warning("Failed to find scope of probe point.\n");
902 ret = call_probe_finder(sc_die, pf);
905 * Continue if no error, because the lazy pattern will match
908 return ret < 0 ? ret : 0;
911 /* Find probe points from lazy pattern */
912 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
916 if (list_empty(&pf->lcache)) {
917 /* Matching lazy line pattern */
918 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
919 pf->pev->point.lazy_line);
924 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
927 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
929 struct probe_finder *pf = data;
930 struct perf_probe_point *pp = &pf->pev->point;
935 ret = find_probe_point_lazy(in_die, pf);
937 /* Get probe address */
938 if (dwarf_entrypc(in_die, &addr) != 0) {
939 pr_warning("Failed to get entry address of %s.\n",
940 dwarf_diename(in_die));
944 pf->addr += pp->offset;
945 pr_debug("found inline addr: 0x%jx\n",
946 (uintmax_t)pf->addr);
948 ret = call_probe_finder(in_die, pf);
954 /* Callback parameter with return value for libdw */
955 struct dwarf_callback_param {
960 /* Search function from function name */
961 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
963 struct dwarf_callback_param *param = data;
964 struct probe_finder *pf = param->data;
965 struct perf_probe_point *pp = &pf->pev->point;
967 /* Check tag and diename */
968 if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
969 !die_compare_name(sp_die, pp->function))
972 /* Check declared file */
973 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
976 pf->fname = dwarf_decl_file(sp_die);
977 if (pp->line) { /* Function relative line */
978 dwarf_decl_line(sp_die, &pf->lno);
980 param->retval = find_probe_point_by_line(pf);
981 } else if (!dwarf_func_inline(sp_die)) {
984 param->retval = find_probe_point_lazy(sp_die, pf);
986 if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
987 pr_warning("Failed to get entry address of "
988 "%s.\n", dwarf_diename(sp_die));
989 param->retval = -ENOENT;
990 return DWARF_CB_ABORT;
992 pf->addr += pp->offset;
993 /* TODO: Check the address in this function */
994 param->retval = call_probe_finder(sp_die, pf);
997 /* Inlined function: search instances */
998 param->retval = die_walk_instances(sp_die,
999 probe_point_inline_cb, (void *)pf);
1001 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1004 static int find_probe_point_by_func(struct probe_finder *pf)
1006 struct dwarf_callback_param _param = {.data = (void *)pf,
1008 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1009 return _param.retval;
1012 struct pubname_callback_param {
1020 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1022 struct pubname_callback_param *param = data;
1024 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1025 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1028 if (die_compare_name(param->sp_die, param->function)) {
1029 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1033 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1037 return DWARF_CB_ABORT;
1044 /* Find probe points from debuginfo */
1045 static int debuginfo__find_probes(struct debuginfo *self,
1046 struct probe_finder *pf)
1048 struct perf_probe_point *pp = &pf->pev->point;
1049 Dwarf_Off off, noff;
1054 #if _ELFUTILS_PREREQ(0, 142)
1055 /* Get the call frame information from this dwarf */
1056 pf->cfi = dwarf_getcfi(self->dbg);
1060 line_list__init(&pf->lcache);
1062 /* Fastpath: lookup by function name from .debug_pubnames section */
1064 struct pubname_callback_param pubname_param = {
1065 .function = pp->function,
1067 .cu_die = &pf->cu_die,
1068 .sp_die = &pf->sp_die,
1071 struct dwarf_callback_param probe_param = {
1075 dwarf_getpubnames(self->dbg, pubname_search_cb,
1077 if (pubname_param.found) {
1078 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1084 /* Loop on CUs (Compilation Unit) */
1085 while (!dwarf_nextcu(self->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1086 /* Get the DIE(Debugging Information Entry) of this CU */
1087 diep = dwarf_offdie(self->dbg, off + cuhl, &pf->cu_die);
1091 /* Check if target file is included. */
1093 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1097 if (!pp->file || pf->fname) {
1099 ret = find_probe_point_by_func(pf);
1100 else if (pp->lazy_line)
1101 ret = find_probe_point_lazy(NULL, pf);
1104 ret = find_probe_point_by_line(pf);
1113 line_list__free(&pf->lcache);
1118 /* Add a found probe point into trace event list */
1119 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1121 struct trace_event_finder *tf =
1122 container_of(pf, struct trace_event_finder, pf);
1123 struct probe_trace_event *tev;
1126 /* Check number of tevs */
1127 if (tf->ntevs == tf->max_tevs) {
1128 pr_warning("Too many( > %d) probe point found.\n",
1132 tev = &tf->tevs[tf->ntevs++];
1134 /* Trace point should be converted from subprogram DIE */
1135 ret = convert_to_trace_point(&pf->sp_die, pf->addr,
1136 pf->pev->point.retprobe, &tev->point);
1140 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1143 /* Find each argument */
1144 tev->nargs = pf->pev->nargs;
1145 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1146 if (tev->args == NULL)
1148 for (i = 0; i < pf->pev->nargs; i++) {
1149 pf->pvar = &pf->pev->args[i];
1150 pf->tvar = &tev->args[i];
1151 /* Variable should be found from scope DIE */
1152 ret = find_variable(sc_die, pf);
1160 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1161 int debuginfo__find_trace_events(struct debuginfo *self,
1162 struct perf_probe_event *pev,
1163 struct probe_trace_event **tevs, int max_tevs)
1165 struct trace_event_finder tf = {
1166 .pf = {.pev = pev, .callback = add_probe_trace_event},
1167 .max_tevs = max_tevs};
1170 /* Allocate result tevs array */
1171 *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1178 ret = debuginfo__find_probes(self, &tf.pf);
1185 return (ret < 0) ? ret : tf.ntevs;
1188 #define MAX_VAR_LEN 64
1190 /* Collect available variables in this scope */
1191 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1193 struct available_var_finder *af = data;
1194 struct variable_list *vl;
1195 char buf[MAX_VAR_LEN];
1198 vl = &af->vls[af->nvls - 1];
1200 tag = dwarf_tag(die_mem);
1201 if (tag == DW_TAG_formal_parameter ||
1202 tag == DW_TAG_variable) {
1203 ret = convert_variable_location(die_mem, af->pf.addr,
1204 af->pf.fb_ops, NULL);
1206 ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1207 pr_debug2("Add new var: %s\n", buf);
1209 strlist__add(vl->vars, buf);
1213 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1214 return DIE_FIND_CB_CONTINUE;
1216 return DIE_FIND_CB_SIBLING;
1219 /* Add a found vars into available variables list */
1220 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1222 struct available_var_finder *af =
1223 container_of(pf, struct available_var_finder, pf);
1224 struct variable_list *vl;
1228 /* Check number of tevs */
1229 if (af->nvls == af->max_vls) {
1230 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1233 vl = &af->vls[af->nvls++];
1235 /* Trace point should be converted from subprogram DIE */
1236 ret = convert_to_trace_point(&pf->sp_die, pf->addr,
1237 pf->pev->point.retprobe, &vl->point);
1241 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1244 /* Find local variables */
1245 vl->vars = strlist__new(true, NULL);
1246 if (vl->vars == NULL)
1249 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1251 /* Find external variables */
1254 /* Don't need to search child DIE for externs. */
1256 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1259 if (strlist__empty(vl->vars)) {
1260 strlist__delete(vl->vars);
1267 /* Find available variables at given probe point */
1268 int debuginfo__find_available_vars_at(struct debuginfo *self,
1269 struct perf_probe_event *pev,
1270 struct variable_list **vls,
1271 int max_vls, bool externs)
1273 struct available_var_finder af = {
1274 .pf = {.pev = pev, .callback = add_available_vars},
1275 .max_vls = max_vls, .externs = externs};
1278 /* Allocate result vls array */
1279 *vls = zalloc(sizeof(struct variable_list) * max_vls);
1286 ret = debuginfo__find_probes(self, &af.pf);
1288 /* Free vlist for error */
1290 if (af.vls[af.nvls].point.symbol)
1291 free(af.vls[af.nvls].point.symbol);
1292 if (af.vls[af.nvls].vars)
1293 strlist__delete(af.vls[af.nvls].vars);
1300 return (ret < 0) ? ret : af.nvls;
1303 /* Reverse search */
1304 int debuginfo__find_probe_point(struct debuginfo *self, unsigned long addr,
1305 struct perf_probe_point *ppt)
1307 Dwarf_Die cudie, spdie, indie;
1308 Dwarf_Addr _addr, baseaddr;
1309 const char *fname = NULL, *func = NULL, *tmp;
1310 int baseline = 0, lineno = 0, ret = 0;
1312 /* Adjust address with bias */
1316 if (!dwarf_addrdie(self->dbg, (Dwarf_Addr)addr - self->bias, &cudie)) {
1317 pr_warning("Failed to find debug information for address %lx\n",
1323 /* Find a corresponding line (filename and lineno) */
1324 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1325 /* Don't care whether it failed or not */
1327 /* Find a corresponding function (name, baseline and baseaddr) */
1328 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1329 /* Get function entry information */
1330 tmp = dwarf_diename(&spdie);
1332 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1333 dwarf_decl_line(&spdie, &baseline) != 0)
1337 if (addr == (unsigned long)baseaddr)
1338 /* Function entry - Relative line number is 0 */
1340 else if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
1342 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1345 * addr is at an inline function entry.
1346 * In this case, lineno should be the call-site
1349 lineno = die_get_call_lineno(&indie);
1352 * addr is in an inline function body.
1353 * Since lineno points one of the lines
1354 * of the inline function, baseline should
1355 * be the entry line of the inline function.
1357 tmp = dwarf_diename(&indie);
1359 dwarf_decl_line(&spdie, &baseline) == 0)
1366 /* Make a relative line number or an offset */
1368 ppt->line = lineno - baseline;
1370 ppt->offset = addr - (unsigned long)baseaddr;
1372 /* Duplicate strings */
1374 ppt->function = strdup(func);
1375 if (ppt->function == NULL) {
1381 ppt->file = strdup(fname);
1382 if (ppt->file == NULL) {
1383 if (ppt->function) {
1384 free(ppt->function);
1385 ppt->function = NULL;
1392 if (ret == 0 && (fname || func))
1393 ret = 1; /* Found a point */
1397 /* Add a line and store the src path */
1398 static int line_range_add_line(const char *src, unsigned int lineno,
1399 struct line_range *lr)
1401 /* Copy source path */
1403 lr->path = strdup(src);
1404 if (lr->path == NULL)
1407 return line_list__add_line(&lr->line_list, lineno);
1410 static int line_range_walk_cb(const char *fname, int lineno,
1411 Dwarf_Addr addr __used,
1414 struct line_finder *lf = data;
1416 if ((strtailcmp(fname, lf->fname) != 0) ||
1417 (lf->lno_s > lineno || lf->lno_e < lineno))
1420 if (line_range_add_line(fname, lineno, lf->lr) < 0)
1426 /* Find line range from its line number */
1427 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1431 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1435 if (!list_empty(&lf->lr->line_list))
1436 ret = lf->found = 1;
1438 ret = 0; /* Lines are not found */
1441 lf->lr->path = NULL;
1446 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1448 find_line_range_by_line(in_die, data);
1451 * We have to check all instances of inlined function, because
1452 * some execution paths can be optimized out depends on the
1453 * function argument of instances
1458 /* Search function from function name */
1459 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1461 struct dwarf_callback_param *param = data;
1462 struct line_finder *lf = param->data;
1463 struct line_range *lr = lf->lr;
1465 /* Check declared file */
1466 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1469 if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
1470 die_compare_name(sp_die, lr->function)) {
1471 lf->fname = dwarf_decl_file(sp_die);
1472 dwarf_decl_line(sp_die, &lr->offset);
1473 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1474 lf->lno_s = lr->offset + lr->start;
1475 if (lf->lno_s < 0) /* Overflow */
1476 lf->lno_s = INT_MAX;
1477 lf->lno_e = lr->offset + lr->end;
1478 if (lf->lno_e < 0) /* Overflow */
1479 lf->lno_e = INT_MAX;
1480 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1481 lr->start = lf->lno_s;
1482 lr->end = lf->lno_e;
1483 if (dwarf_func_inline(sp_die))
1484 param->retval = die_walk_instances(sp_die,
1485 line_range_inline_cb, lf);
1487 param->retval = find_line_range_by_line(sp_die, lf);
1488 return DWARF_CB_ABORT;
1493 static int find_line_range_by_func(struct line_finder *lf)
1495 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1496 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1497 return param.retval;
1500 int debuginfo__find_line_range(struct debuginfo *self, struct line_range *lr)
1502 struct line_finder lf = {.lr = lr, .found = 0};
1504 Dwarf_Off off = 0, noff;
1507 const char *comp_dir;
1509 /* Fastpath: lookup by function name from .debug_pubnames section */
1511 struct pubname_callback_param pubname_param = {
1512 .function = lr->function, .file = lr->file,
1513 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1514 struct dwarf_callback_param line_range_param = {
1515 .data = (void *)&lf, .retval = 0};
1517 dwarf_getpubnames(self->dbg, pubname_search_cb,
1519 if (pubname_param.found) {
1520 line_range_search_cb(&lf.sp_die, &line_range_param);
1526 /* Loop on CUs (Compilation Unit) */
1527 while (!lf.found && ret >= 0) {
1528 if (dwarf_nextcu(self->dbg, off, &noff, &cuhl,
1529 NULL, NULL, NULL) != 0)
1532 /* Get the DIE(Debugging Information Entry) of this CU */
1533 diep = dwarf_offdie(self->dbg, off + cuhl, &lf.cu_die);
1537 /* Check if target file is included. */
1539 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1543 if (!lr->file || lf.fname) {
1545 ret = find_line_range_by_func(&lf);
1547 lf.lno_s = lr->start;
1549 ret = find_line_range_by_line(NULL, &lf);
1556 /* Store comp_dir */
1558 comp_dir = cu_get_comp_dir(&lf.cu_die);
1560 lr->comp_dir = strdup(comp_dir);
1566 pr_debug("path: %s\n", lr->path);
1567 return (ret < 0) ? ret : lf.found;