aboutsummaryrefslogtreecommitdiffstats
path: root/tools/perf/util/probe-finder.c
diff options
context:
space:
mode:
authorMasami Hiramatsu <mhiramat@redhat.com>2010-05-19 15:57:49 -0400
committerArnaldo Carvalho de Melo <acme@redhat.com>2010-07-05 17:51:33 -0400
commitb7dcb857cc3eb89136111fefe89780129c1af1d7 (patch)
tree21350796c508db4fb782f3e61eb63f62c3527f69 /tools/perf/util/probe-finder.c
parentb2a3c12b7442247c440f7083d48ef05716753ec1 (diff)
perf probe: Support static and global variables
Add static and global variables support to perf probe. This allows user to trace non-local variables (and structure members) at probe points. Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20100519195749.2885.17451.stgit@localhost6.localdomain6> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/probe-finder.c')
-rw-r--r--tools/perf/util/probe-finder.c85
1 files changed, 61 insertions, 24 deletions
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 308664deb857..3e64e1fa1051 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -406,14 +406,50 @@ static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
406 * Probe finder related functions 406 * Probe finder related functions
407 */ 407 */
408 408
409static struct kprobe_trace_arg_ref *alloc_trace_arg_ref(long offs)
410{
411 struct kprobe_trace_arg_ref *ref;
412 ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
413 if (ref != NULL)
414 ref->offset = offs;
415 return ref;
416}
417
409/* Show a location */ 418/* Show a location */
410static int convert_location(Dwarf_Op *op, struct probe_finder *pf) 419static int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
411{ 420{
421 Dwarf_Attribute attr;
422 Dwarf_Op *op;
423 size_t nops;
412 unsigned int regn; 424 unsigned int regn;
413 Dwarf_Word offs = 0; 425 Dwarf_Word offs = 0;
414 bool ref = false; 426 bool ref = false;
415 const char *regs; 427 const char *regs;
416 struct kprobe_trace_arg *tvar = pf->tvar; 428 struct kprobe_trace_arg *tvar = pf->tvar;
429 int ret;
430
431 /* TODO: handle more than 1 exprs */
432 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
433 dwarf_getlocation_addr(&attr, pf->addr, &op, &nops, 1) <= 0 ||
434 nops == 0) {
435 /* TODO: Support const_value */
436 pr_err("Failed to find the location of %s at this address.\n"
437 " Perhaps, it has been optimized out.\n", pf->pvar->var);
438 return -ENOENT;
439 }
440
441 if (op->atom == DW_OP_addr) {
442 /* Static variables on memory (not stack), make @varname */
443 ret = strlen(dwarf_diename(vr_die));
444 tvar->value = zalloc(ret + 2);
445 if (tvar->value == NULL)
446 return -ENOMEM;
447 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
448 tvar->ref = alloc_trace_arg_ref((long)offs);
449 if (tvar->ref == NULL)
450 return -ENOMEM;
451 return 0;
452 }
417 453
418 /* If this is based on frame buffer, set the offset */ 454 /* If this is based on frame buffer, set the offset */
419 if (op->atom == DW_OP_fbreg) { 455 if (op->atom == DW_OP_fbreg) {
@@ -455,10 +491,9 @@ static int convert_location(Dwarf_Op *op, struct probe_finder *pf)
455 return -ENOMEM; 491 return -ENOMEM;
456 492
457 if (ref) { 493 if (ref) {
458 tvar->ref = zalloc(sizeof(struct kprobe_trace_arg_ref)); 494 tvar->ref = alloc_trace_arg_ref((long)offs);
459 if (tvar->ref == NULL) 495 if (tvar->ref == NULL)
460 return -ENOMEM; 496 return -ENOMEM;
461 tvar->ref->offset = (long)offs;
462 } 497 }
463 return 0; 498 return 0;
464} 499}
@@ -666,20 +701,13 @@ next:
666/* Show a variables in kprobe event format */ 701/* Show a variables in kprobe event format */
667static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf) 702static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
668{ 703{
669 Dwarf_Attribute attr;
670 Dwarf_Die die_mem; 704 Dwarf_Die die_mem;
671 Dwarf_Op *expr;
672 size_t nexpr;
673 int ret; 705 int ret;
674 706
675 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL) 707 pr_debug("Converting variable %s into trace event.\n",
676 goto error; 708 dwarf_diename(vr_die));
677 /* TODO: handle more than 1 exprs */
678 ret = dwarf_getlocation_addr(&attr, pf->addr, &expr, &nexpr, 1);
679 if (ret <= 0 || nexpr == 0)
680 goto error;
681 709
682 ret = convert_location(expr, pf); 710 ret = convert_variable_location(vr_die, pf);
683 if (ret == 0 && pf->pvar->field) { 711 if (ret == 0 && pf->pvar->field) {
684 ret = convert_variable_fields(vr_die, pf->pvar->var, 712 ret = convert_variable_fields(vr_die, pf->pvar->var,
685 pf->pvar->field, &pf->tvar->ref, 713 pf->pvar->field, &pf->tvar->ref,
@@ -690,19 +718,14 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
690 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type); 718 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
691 /* *expr will be cached in libdw. Don't free it. */ 719 /* *expr will be cached in libdw. Don't free it. */
692 return ret; 720 return ret;
693error:
694 /* TODO: Support const_value */
695 pr_err("Failed to find the location of %s at this address.\n"
696 " Perhaps, it has been optimized out.\n", pf->pvar->var);
697 return -ENOENT;
698} 721}
699 722
700/* Find a variable in a subprogram die */ 723/* Find a variable in a subprogram die */
701static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf) 724static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
702{ 725{
703 Dwarf_Die vr_die; 726 Dwarf_Die vr_die, *scopes;
704 char buf[32], *ptr; 727 char buf[32], *ptr;
705 int ret; 728 int ret, nscopes;
706 729
707 if (pf->pvar->name) 730 if (pf->pvar->name)
708 pf->tvar->name = strdup(pf->pvar->name); 731 pf->tvar->name = strdup(pf->pvar->name);
@@ -730,12 +753,26 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
730 pr_debug("Searching '%s' variable in context.\n", 753 pr_debug("Searching '%s' variable in context.\n",
731 pf->pvar->var); 754 pf->pvar->var);
732 /* Search child die for local variables and parameters. */ 755 /* Search child die for local variables and parameters. */
733 if (!die_find_variable(sp_die, pf->pvar->var, &vr_die)) { 756 if (die_find_variable(sp_die, pf->pvar->var, &vr_die))
757 ret = convert_variable(&vr_die, pf);
758 else {
759 /* Search upper class */
760 nscopes = dwarf_getscopes_die(sp_die, &scopes);
761 if (nscopes > 0) {
762 ret = dwarf_getscopevar(scopes, nscopes, pf->pvar->var,
763 0, NULL, 0, 0, &vr_die);
764 if (ret >= 0)
765 ret = convert_variable(&vr_die, pf);
766 else
767 ret = -ENOENT;
768 free(scopes);
769 } else
770 ret = -ENOENT;
771 }
772 if (ret < 0)
734 pr_warning("Failed to find '%s' in this function.\n", 773 pr_warning("Failed to find '%s' in this function.\n",
735 pf->pvar->var); 774 pf->pvar->var);
736 return -ENOENT; 775 return ret;
737 }
738 return convert_variable(&vr_die, pf);
739} 776}
740 777
741/* Show a probe point to output buffer */ 778/* Show a probe point to output buffer */