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Date: Wed, 23 Oct 2013 17:58:03 -0300
From: Arnaldo Carvalho de Melo <acme@...radead.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: linux-kernel@...r.kernel.org,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Ingo Molnar <mingo@...hat.com>,
Paul Mackerras <paulus@...ba.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 04/16] perf probe: Support "$vars" meta argument syntax for local variables
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Support "$vars" meta argument syntax for tracing all local variables at
probe point.
Now you can trace all available local variables (including function
parameters) at the probe point by passing $vars.
# perf probe --add foo $vars
This automatically finds all local variables at foo() and adds it as
probe arguments.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Link: http://lkml.kernel.org/r/20131011071023.15557.51770.stgit@udc4-manage.rcp.hitachi.co.jp
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
tools/perf/util/probe-event.c | 1 -
tools/perf/util/probe-finder.c | 96 ++++++++++++++++++++++++++++++++++++++----
tools/perf/util/probe-finder.h | 1 +
3 files changed, 89 insertions(+), 9 deletions(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 779b2dacd43f..9c6989ca2bea 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -47,7 +47,6 @@
#include "session.h"
#define MAX_CMDLEN 256
-#define MAX_PROBE_ARGS 128
#define PERFPROBE_GROUP "probe"
bool probe_event_dry_run; /* Dry run flag */
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index c09e0a9fdf4c..5a46be968c0b 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1136,12 +1136,78 @@ found:
return ret;
}
+struct local_vars_finder {
+ struct probe_finder *pf;
+ struct perf_probe_arg *args;
+ int max_args;
+ int nargs;
+ int ret;
+};
+
+/* Collect available variables in this scope */
+static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
+{
+ struct local_vars_finder *vf = data;
+ int tag;
+
+ tag = dwarf_tag(die_mem);
+ if (tag == DW_TAG_formal_parameter ||
+ tag == DW_TAG_variable) {
+ if (convert_variable_location(die_mem, vf->pf->addr,
+ vf->pf->fb_ops, NULL) == 0) {
+ vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
+ if (vf->args[vf->nargs].var == NULL) {
+ vf->ret = -ENOMEM;
+ return DIE_FIND_CB_END;
+ }
+ pr_debug(" %s", vf->args[vf->nargs].var);
+ vf->nargs++;
+ }
+ }
+
+ if (dwarf_haspc(die_mem, vf->pf->addr))
+ return DIE_FIND_CB_CONTINUE;
+ else
+ return DIE_FIND_CB_SIBLING;
+}
+
+static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
+ struct perf_probe_arg *args)
+{
+ Dwarf_Die die_mem;
+ int i;
+ int n = 0;
+ struct local_vars_finder vf = {.pf = pf, .args = args,
+ .max_args = MAX_PROBE_ARGS, .ret = 0};
+
+ for (i = 0; i < pf->pev->nargs; i++) {
+ /* var never be NULL */
+ if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
+ pr_debug("Expanding $vars into:");
+ vf.nargs = n;
+ /* Special local variables */
+ die_find_child(sc_die, copy_variables_cb, (void *)&vf,
+ &die_mem);
+ pr_debug(" (%d)\n", vf.nargs - n);
+ if (vf.ret < 0)
+ return vf.ret;
+ n = vf.nargs;
+ } else {
+ /* Copy normal argument */
+ args[n] = pf->pev->args[i];
+ n++;
+ }
+ }
+ return n;
+}
+
/* Add a found probe point into trace event list */
static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
{
struct trace_event_finder *tf =
container_of(pf, struct trace_event_finder, pf);
struct probe_trace_event *tev;
+ struct perf_probe_arg *args;
int ret, i;
/* Check number of tevs */
@@ -1161,21 +1227,35 @@ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
tev->point.offset);
- /* Find each argument */
- tev->nargs = pf->pev->nargs;
- tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
- if (tev->args == NULL)
+ /* Expand special probe argument if exist */
+ args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
+ if (args == NULL)
return -ENOMEM;
- for (i = 0; i < pf->pev->nargs; i++) {
- pf->pvar = &pf->pev->args[i];
+
+ ret = expand_probe_args(sc_die, pf, args);
+ if (ret < 0)
+ goto end;
+
+ tev->nargs = ret;
+ tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
+ if (tev->args == NULL) {
+ ret = -ENOMEM;
+ goto end;
+ }
+
+ /* Find each argument */
+ for (i = 0; i < tev->nargs; i++) {
+ pf->pvar = &args[i];
pf->tvar = &tev->args[i];
/* Variable should be found from scope DIE */
ret = find_variable(sc_die, pf);
if (ret != 0)
- return ret;
+ break;
}
- return 0;
+end:
+ free(args);
+ return ret;
}
/* Find probe_trace_events specified by perf_probe_event from debuginfo */
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 3f0c29dd6ac5..d6dab0e0a937 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -7,6 +7,7 @@
#define MAX_PROBE_BUFFER 1024
#define MAX_PROBES 128
+#define MAX_PROBE_ARGS 128
static inline int is_c_varname(const char *name)
{
--
1.8.1.4
--
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