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 __used)
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 (ret == DW_TAG_pointer_type) {
417 if (die_get_real_type(&type, &type) == NULL) {
418 pr_warning("Failed to get a 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 if (dwarf_tag(&type) != DW_TAG_structure_type) {
529 pr_warning("%s is not a data structure.\n", varname);
533 ref = zalloc(sizeof(struct probe_trace_arg_ref));
537 (*ref_ptr)->next = ref;
541 /* Verify it is a data structure */
542 if (tag != DW_TAG_structure_type) {
543 pr_warning("%s is not a data structure.\n", varname);
546 if (field->name[0] == '[') {
547 pr_err("Semantic error: %s is not a pointor"
548 " nor array.\n", varname);
552 pr_err("Semantic error: %s must be referred by '.'\n",
557 pr_warning("Structure on a register is not "
563 if (die_find_member(&type, field->name, die_mem) == NULL) {
564 pr_warning("%s(tyep:%s) has no member %s.\n", varname,
565 dwarf_diename(&type), field->name);
569 /* Get the offset of the field */
570 ret = die_get_data_member_location(die_mem, &offs);
572 pr_warning("Failed to get the offset of %s.\n", field->name);
575 ref->offset += (long)offs;
578 /* Converting next field */
580 return convert_variable_fields(die_mem, field->name,
581 field->next, &ref, die_mem);
586 /* Show a variables in kprobe event format */
587 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
592 pr_debug("Converting variable %s into trace event.\n",
593 dwarf_diename(vr_die));
595 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
598 pr_err("Failed to find the location of %s at this address.\n"
599 " Perhaps, it has been optimized out.\n", pf->pvar->var);
600 else if (ret == -ENOTSUP)
601 pr_err("Sorry, we don't support this variable location yet.\n");
602 else if (pf->pvar->field) {
603 ret = convert_variable_fields(vr_die, pf->pvar->var,
604 pf->pvar->field, &pf->tvar->ref,
609 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
610 /* *expr will be cached in libdw. Don't free it. */
614 /* Find a variable in a scope DIE */
615 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
621 if (!is_c_varname(pf->pvar->var)) {
622 /* Copy raw parameters */
623 pf->tvar->value = strdup(pf->pvar->var);
624 if (pf->tvar->value == NULL)
626 if (pf->pvar->type) {
627 pf->tvar->type = strdup(pf->pvar->type);
628 if (pf->tvar->type == NULL)
631 if (pf->pvar->name) {
632 pf->tvar->name = strdup(pf->pvar->name);
633 if (pf->tvar->name == NULL)
636 pf->tvar->name = NULL;
641 pf->tvar->name = strdup(pf->pvar->name);
643 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
646 ptr = strchr(buf, ':'); /* Change type separator to _ */
649 pf->tvar->name = strdup(buf);
651 if (pf->tvar->name == NULL)
654 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
655 /* Search child die for local variables and parameters. */
656 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
657 /* Search again in global variables */
658 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
662 ret = convert_variable(&vr_die, pf);
665 pr_warning("Failed to find '%s' in this function.\n",
670 /* Convert subprogram DIE to trace point */
671 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
672 bool retprobe, struct probe_trace_point *tp)
674 Dwarf_Addr eaddr, highaddr;
677 /* Copy the name of probe point */
678 name = dwarf_diename(sp_die);
680 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
681 pr_warning("Failed to get entry address of %s\n",
682 dwarf_diename(sp_die));
685 if (dwarf_highpc(sp_die, &highaddr) != 0) {
686 pr_warning("Failed to get end address of %s\n",
687 dwarf_diename(sp_die));
690 if (paddr > highaddr) {
691 pr_warning("Offset specified is greater than size of %s\n",
692 dwarf_diename(sp_die));
695 tp->symbol = strdup(name);
696 if (tp->symbol == NULL)
698 tp->offset = (unsigned long)(paddr - eaddr);
700 /* This function has no name. */
701 tp->offset = (unsigned long)paddr;
703 /* Return probe must be on the head of a subprogram */
705 if (eaddr != paddr) {
706 pr_warning("Return probe must be on the head of"
707 " a real function.\n");
716 /* Call probe_finder callback with scope DIE */
717 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
719 Dwarf_Attribute fb_attr;
724 pr_err("Caller must pass a scope DIE. Program error.\n");
728 /* If not a real subprogram, find a real one */
729 if (dwarf_tag(sc_die) != DW_TAG_subprogram) {
730 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
731 pr_warning("Failed to find probe point in any "
736 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
738 /* Get the frame base attribute/ops from subprogram */
739 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
740 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
741 if (ret <= 0 || nops == 0) {
743 #if _ELFUTILS_PREREQ(0, 142)
744 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
747 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
748 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
749 pr_warning("Failed to get call frame on 0x%jx\n",
750 (uintmax_t)pf->addr);
756 /* Call finder's callback handler */
757 ret = pf->callback(sc_die, pf);
759 /* *pf->fb_ops will be cached in libdw. Don't free it. */
765 struct find_scope_param {
766 const char *function;
774 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
776 struct find_scope_param *fsp = data;
780 /* Skip if declared file name does not match */
782 file = dwarf_decl_file(fn_die);
783 if (!file || strcmp(fsp->file, file) != 0)
786 /* If the function name is given, that's what user expects */
788 if (die_compare_name(fn_die, fsp->function)) {
789 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
794 /* With the line number, find the nearest declared DIE */
795 dwarf_decl_line(fn_die, &lno);
796 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
797 /* Keep a candidate and continue */
798 fsp->diff = fsp->line - lno;
799 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
806 /* Find an appropriate scope fits to given conditions */
807 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
809 struct find_scope_param fsp = {
810 .function = pf->pev->point.function,
818 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
820 return fsp.found ? die_mem : NULL;
823 static int probe_point_line_walker(const char *fname, int lineno,
824 Dwarf_Addr addr, void *data)
826 struct probe_finder *pf = data;
827 Dwarf_Die *sc_die, die_mem;
830 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
834 sc_die = find_best_scope(pf, &die_mem);
836 pr_warning("Failed to find scope of probe point.\n");
840 ret = call_probe_finder(sc_die, pf);
842 /* Continue if no error, because the line will be in inline function */
843 return ret < 0 ? ret : 0;
846 /* Find probe point from its line number */
847 static int find_probe_point_by_line(struct probe_finder *pf)
849 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
852 /* Find lines which match lazy pattern */
853 static int find_lazy_match_lines(struct list_head *head,
854 const char *fname, const char *pat)
860 int count = 0, linenum = 1;
862 fp = fopen(fname, "r");
864 pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
868 while ((len = getline(&line, &line_len, fp)) > 0) {
870 if (line[len - 1] == '\n')
871 line[len - 1] = '\0';
873 if (strlazymatch(line, pat)) {
874 line_list__add_line(head, linenum);
886 pr_debug("No matched lines found in %s.\n", fname);
890 static int probe_point_lazy_walker(const char *fname, int lineno,
891 Dwarf_Addr addr, void *data)
893 struct probe_finder *pf = data;
894 Dwarf_Die *sc_die, die_mem;
897 if (!line_list__has_line(&pf->lcache, lineno) ||
898 strtailcmp(fname, pf->fname) != 0)
901 pr_debug("Probe line found: line:%d addr:0x%llx\n",
902 lineno, (unsigned long long)addr);
905 sc_die = find_best_scope(pf, &die_mem);
907 pr_warning("Failed to find scope of probe point.\n");
911 ret = call_probe_finder(sc_die, pf);
914 * Continue if no error, because the lazy pattern will match
917 return ret < 0 ? ret : 0;
920 /* Find probe points from lazy pattern */
921 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
925 if (list_empty(&pf->lcache)) {
926 /* Matching lazy line pattern */
927 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
928 pf->pev->point.lazy_line);
933 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
936 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
938 struct probe_finder *pf = data;
939 struct perf_probe_point *pp = &pf->pev->point;
944 ret = find_probe_point_lazy(in_die, pf);
946 /* Get probe address */
947 if (dwarf_entrypc(in_die, &addr) != 0) {
948 pr_warning("Failed to get entry address of %s.\n",
949 dwarf_diename(in_die));
953 pf->addr += pp->offset;
954 pr_debug("found inline addr: 0x%jx\n",
955 (uintmax_t)pf->addr);
957 ret = call_probe_finder(in_die, pf);
963 /* Callback parameter with return value for libdw */
964 struct dwarf_callback_param {
969 /* Search function from function name */
970 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
972 struct dwarf_callback_param *param = data;
973 struct probe_finder *pf = param->data;
974 struct perf_probe_point *pp = &pf->pev->point;
975 Dwarf_Attribute attr;
977 /* Check tag and diename */
978 if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
979 !die_compare_name(sp_die, pp->function) ||
980 dwarf_attr(sp_die, DW_AT_declaration, &attr))
983 /* Check declared file */
984 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
987 pf->fname = dwarf_decl_file(sp_die);
988 if (pp->line) { /* Function relative line */
989 dwarf_decl_line(sp_die, &pf->lno);
991 param->retval = find_probe_point_by_line(pf);
992 } else if (!dwarf_func_inline(sp_die)) {
995 param->retval = find_probe_point_lazy(sp_die, pf);
997 if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
998 pr_warning("Failed to get entry address of "
999 "%s.\n", dwarf_diename(sp_die));
1000 param->retval = -ENOENT;
1001 return DWARF_CB_ABORT;
1003 pf->addr += pp->offset;
1004 /* TODO: Check the address in this function */
1005 param->retval = call_probe_finder(sp_die, pf);
1008 /* Inlined function: search instances */
1009 param->retval = die_walk_instances(sp_die,
1010 probe_point_inline_cb, (void *)pf);
1012 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1015 static int find_probe_point_by_func(struct probe_finder *pf)
1017 struct dwarf_callback_param _param = {.data = (void *)pf,
1019 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1020 return _param.retval;
1023 struct pubname_callback_param {
1031 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1033 struct pubname_callback_param *param = data;
1035 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1036 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1039 if (die_compare_name(param->sp_die, param->function)) {
1040 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1044 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1048 return DWARF_CB_ABORT;
1055 /* Find probe points from debuginfo */
1056 static int debuginfo__find_probes(struct debuginfo *self,
1057 struct probe_finder *pf)
1059 struct perf_probe_point *pp = &pf->pev->point;
1060 Dwarf_Off off, noff;
1065 #if _ELFUTILS_PREREQ(0, 142)
1066 /* Get the call frame information from this dwarf */
1067 pf->cfi = dwarf_getcfi(self->dbg);
1071 line_list__init(&pf->lcache);
1073 /* Fastpath: lookup by function name from .debug_pubnames section */
1075 struct pubname_callback_param pubname_param = {
1076 .function = pp->function,
1078 .cu_die = &pf->cu_die,
1079 .sp_die = &pf->sp_die,
1082 struct dwarf_callback_param probe_param = {
1086 dwarf_getpubnames(self->dbg, pubname_search_cb,
1088 if (pubname_param.found) {
1089 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1095 /* Loop on CUs (Compilation Unit) */
1096 while (!dwarf_nextcu(self->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1097 /* Get the DIE(Debugging Information Entry) of this CU */
1098 diep = dwarf_offdie(self->dbg, off + cuhl, &pf->cu_die);
1102 /* Check if target file is included. */
1104 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1108 if (!pp->file || pf->fname) {
1110 ret = find_probe_point_by_func(pf);
1111 else if (pp->lazy_line)
1112 ret = find_probe_point_lazy(NULL, pf);
1115 ret = find_probe_point_by_line(pf);
1124 line_list__free(&pf->lcache);
1129 /* Add a found probe point into trace event list */
1130 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1132 struct trace_event_finder *tf =
1133 container_of(pf, struct trace_event_finder, pf);
1134 struct probe_trace_event *tev;
1137 /* Check number of tevs */
1138 if (tf->ntevs == tf->max_tevs) {
1139 pr_warning("Too many( > %d) probe point found.\n",
1143 tev = &tf->tevs[tf->ntevs++];
1145 /* Trace point should be converted from subprogram DIE */
1146 ret = convert_to_trace_point(&pf->sp_die, pf->addr,
1147 pf->pev->point.retprobe, &tev->point);
1151 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1154 /* Find each argument */
1155 tev->nargs = pf->pev->nargs;
1156 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1157 if (tev->args == NULL)
1159 for (i = 0; i < pf->pev->nargs; i++) {
1160 pf->pvar = &pf->pev->args[i];
1161 pf->tvar = &tev->args[i];
1162 /* Variable should be found from scope DIE */
1163 ret = find_variable(sc_die, pf);
1171 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1172 int debuginfo__find_trace_events(struct debuginfo *self,
1173 struct perf_probe_event *pev,
1174 struct probe_trace_event **tevs, int max_tevs)
1176 struct trace_event_finder tf = {
1177 .pf = {.pev = pev, .callback = add_probe_trace_event},
1178 .max_tevs = max_tevs};
1181 /* Allocate result tevs array */
1182 *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1189 ret = debuginfo__find_probes(self, &tf.pf);
1196 return (ret < 0) ? ret : tf.ntevs;
1199 #define MAX_VAR_LEN 64
1201 /* Collect available variables in this scope */
1202 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1204 struct available_var_finder *af = data;
1205 struct variable_list *vl;
1206 char buf[MAX_VAR_LEN];
1209 vl = &af->vls[af->nvls - 1];
1211 tag = dwarf_tag(die_mem);
1212 if (tag == DW_TAG_formal_parameter ||
1213 tag == DW_TAG_variable) {
1214 ret = convert_variable_location(die_mem, af->pf.addr,
1215 af->pf.fb_ops, NULL);
1217 ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1218 pr_debug2("Add new var: %s\n", buf);
1220 strlist__add(vl->vars, buf);
1224 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1225 return DIE_FIND_CB_CONTINUE;
1227 return DIE_FIND_CB_SIBLING;
1230 /* Add a found vars into available variables list */
1231 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1233 struct available_var_finder *af =
1234 container_of(pf, struct available_var_finder, pf);
1235 struct variable_list *vl;
1239 /* Check number of tevs */
1240 if (af->nvls == af->max_vls) {
1241 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1244 vl = &af->vls[af->nvls++];
1246 /* Trace point should be converted from subprogram DIE */
1247 ret = convert_to_trace_point(&pf->sp_die, pf->addr,
1248 pf->pev->point.retprobe, &vl->point);
1252 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1255 /* Find local variables */
1256 vl->vars = strlist__new(true, NULL);
1257 if (vl->vars == NULL)
1260 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1262 /* Find external variables */
1265 /* Don't need to search child DIE for externs. */
1267 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1270 if (strlist__empty(vl->vars)) {
1271 strlist__delete(vl->vars);
1278 /* Find available variables at given probe point */
1279 int debuginfo__find_available_vars_at(struct debuginfo *self,
1280 struct perf_probe_event *pev,
1281 struct variable_list **vls,
1282 int max_vls, bool externs)
1284 struct available_var_finder af = {
1285 .pf = {.pev = pev, .callback = add_available_vars},
1286 .max_vls = max_vls, .externs = externs};
1289 /* Allocate result vls array */
1290 *vls = zalloc(sizeof(struct variable_list) * max_vls);
1297 ret = debuginfo__find_probes(self, &af.pf);
1299 /* Free vlist for error */
1301 if (af.vls[af.nvls].point.symbol)
1302 free(af.vls[af.nvls].point.symbol);
1303 if (af.vls[af.nvls].vars)
1304 strlist__delete(af.vls[af.nvls].vars);
1311 return (ret < 0) ? ret : af.nvls;
1314 /* Reverse search */
1315 int debuginfo__find_probe_point(struct debuginfo *self, unsigned long addr,
1316 struct perf_probe_point *ppt)
1318 Dwarf_Die cudie, spdie, indie;
1319 Dwarf_Addr _addr, baseaddr;
1320 const char *fname = NULL, *func = NULL, *tmp;
1321 int baseline = 0, lineno = 0, ret = 0;
1323 /* Adjust address with bias */
1327 if (!dwarf_addrdie(self->dbg, (Dwarf_Addr)addr - self->bias, &cudie)) {
1328 pr_warning("Failed to find debug information for address %lx\n",
1334 /* Find a corresponding line (filename and lineno) */
1335 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1336 /* Don't care whether it failed or not */
1338 /* Find a corresponding function (name, baseline and baseaddr) */
1339 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1340 /* Get function entry information */
1341 tmp = dwarf_diename(&spdie);
1343 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1344 dwarf_decl_line(&spdie, &baseline) != 0)
1348 if (addr == (unsigned long)baseaddr)
1349 /* Function entry - Relative line number is 0 */
1351 else if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
1353 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1356 * addr is at an inline function entry.
1357 * In this case, lineno should be the call-site
1360 lineno = die_get_call_lineno(&indie);
1363 * addr is in an inline function body.
1364 * Since lineno points one of the lines
1365 * of the inline function, baseline should
1366 * be the entry line of the inline function.
1368 tmp = dwarf_diename(&indie);
1370 dwarf_decl_line(&spdie, &baseline) == 0)
1377 /* Make a relative line number or an offset */
1379 ppt->line = lineno - baseline;
1381 ppt->offset = addr - (unsigned long)baseaddr;
1383 /* Duplicate strings */
1385 ppt->function = strdup(func);
1386 if (ppt->function == NULL) {
1392 ppt->file = strdup(fname);
1393 if (ppt->file == NULL) {
1394 if (ppt->function) {
1395 free(ppt->function);
1396 ppt->function = NULL;
1403 if (ret == 0 && (fname || func))
1404 ret = 1; /* Found a point */
1408 /* Add a line and store the src path */
1409 static int line_range_add_line(const char *src, unsigned int lineno,
1410 struct line_range *lr)
1412 /* Copy source path */
1414 lr->path = strdup(src);
1415 if (lr->path == NULL)
1418 return line_list__add_line(&lr->line_list, lineno);
1421 static int line_range_walk_cb(const char *fname, int lineno,
1422 Dwarf_Addr addr __used,
1425 struct line_finder *lf = data;
1427 if ((strtailcmp(fname, lf->fname) != 0) ||
1428 (lf->lno_s > lineno || lf->lno_e < lineno))
1431 if (line_range_add_line(fname, lineno, lf->lr) < 0)
1437 /* Find line range from its line number */
1438 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1442 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1446 if (!list_empty(&lf->lr->line_list))
1447 ret = lf->found = 1;
1449 ret = 0; /* Lines are not found */
1452 lf->lr->path = NULL;
1457 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1459 find_line_range_by_line(in_die, data);
1462 * We have to check all instances of inlined function, because
1463 * some execution paths can be optimized out depends on the
1464 * function argument of instances
1469 /* Search function from function name */
1470 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1472 struct dwarf_callback_param *param = data;
1473 struct line_finder *lf = param->data;
1474 struct line_range *lr = lf->lr;
1476 /* Check declared file */
1477 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1480 if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
1481 die_compare_name(sp_die, lr->function)) {
1482 lf->fname = dwarf_decl_file(sp_die);
1483 dwarf_decl_line(sp_die, &lr->offset);
1484 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1485 lf->lno_s = lr->offset + lr->start;
1486 if (lf->lno_s < 0) /* Overflow */
1487 lf->lno_s = INT_MAX;
1488 lf->lno_e = lr->offset + lr->end;
1489 if (lf->lno_e < 0) /* Overflow */
1490 lf->lno_e = INT_MAX;
1491 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1492 lr->start = lf->lno_s;
1493 lr->end = lf->lno_e;
1494 if (dwarf_func_inline(sp_die))
1495 param->retval = die_walk_instances(sp_die,
1496 line_range_inline_cb, lf);
1498 param->retval = find_line_range_by_line(sp_die, lf);
1499 return DWARF_CB_ABORT;
1504 static int find_line_range_by_func(struct line_finder *lf)
1506 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1507 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1508 return param.retval;
1511 int debuginfo__find_line_range(struct debuginfo *self, struct line_range *lr)
1513 struct line_finder lf = {.lr = lr, .found = 0};
1515 Dwarf_Off off = 0, noff;
1518 const char *comp_dir;
1520 /* Fastpath: lookup by function name from .debug_pubnames section */
1522 struct pubname_callback_param pubname_param = {
1523 .function = lr->function, .file = lr->file,
1524 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1525 struct dwarf_callback_param line_range_param = {
1526 .data = (void *)&lf, .retval = 0};
1528 dwarf_getpubnames(self->dbg, pubname_search_cb,
1530 if (pubname_param.found) {
1531 line_range_search_cb(&lf.sp_die, &line_range_param);
1537 /* Loop on CUs (Compilation Unit) */
1538 while (!lf.found && ret >= 0) {
1539 if (dwarf_nextcu(self->dbg, off, &noff, &cuhl,
1540 NULL, NULL, NULL) != 0)
1543 /* Get the DIE(Debugging Information Entry) of this CU */
1544 diep = dwarf_offdie(self->dbg, off + cuhl, &lf.cu_die);
1548 /* Check if target file is included. */
1550 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1554 if (!lr->file || lf.fname) {
1556 ret = find_line_range_by_func(&lf);
1558 lf.lno_s = lr->start;
1560 ret = find_line_range_by_line(NULL, &lf);
1567 /* Store comp_dir */
1569 comp_dir = cu_get_comp_dir(&lf.cu_die);
1571 lr->comp_dir = strdup(comp_dir);
1577 pr_debug("path: %s\n", lr->path);
1578 return (ret < 0) ? ret : lf.found;