Commit fb8c5a56 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo

perf probe: Show accessible global variables

Add --externs for allowing --vars to show accessible global (externally
defined) variables from a given probe point too.

This will give you a hint which globals can be accessible from the probe point.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20101021101335.3542.31003.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent c82ec0a2
......@@ -18,7 +18,7 @@ or
or
'perf probe' --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]'
or
'perf probe' --vars='PROBEPOINT'
'perf probe' [--externs] --vars='PROBEPOINT'
DESCRIPTION
-----------
......@@ -64,6 +64,10 @@ OPTIONS
Show available local variables at given probe point. The argument
syntax is same as PROBE SYNTAX, but NO ARGs.
--externs::
(Only for --vars) Show external defined variables in addition to local
variables.
-f::
--force::
Forcibly add events with existing name.
......
......@@ -51,6 +51,7 @@ static struct {
bool force_add;
bool show_lines;
bool show_vars;
bool show_ext_vars;
bool mod_events;
int nevents;
struct perf_probe_event events[MAX_PROBES];
......@@ -162,7 +163,7 @@ static const char * const probe_usage[] = {
"perf probe --list",
#ifdef DWARF_SUPPORT
"perf probe --line 'LINEDESC'",
"perf probe --vars 'PROBEPOINT'",
"perf probe [--externs] --vars 'PROBEPOINT'",
#endif
NULL
};
......@@ -207,6 +208,8 @@ static const struct option options[] = {
OPT_CALLBACK('V', "vars", NULL,
"FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT",
"Show accessible variables on PROBEDEF", opt_show_vars),
OPT_BOOLEAN('\0', "externs", &params.show_ext_vars,
"Show external variables too (with --vars only)"),
OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
"file", "vmlinux pathname"),
OPT_STRING('s', "source", &symbol_conf.source_prefix,
......@@ -287,7 +290,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
usage_with_options(probe_usage, options);
}
ret = show_available_vars(params.events, params.nevents,
params.max_probe_points);
params.max_probe_points,
params.show_ext_vars);
if (ret < 0)
pr_err(" Error: Failed to show vars. (%d)\n", ret);
return ret;
......
......@@ -379,7 +379,7 @@ int show_line_range(struct line_range *lr)
}
static int show_available_vars_at(int fd, struct perf_probe_event *pev,
int max_vls)
int max_vls, bool externs)
{
char *buf;
int ret, i;
......@@ -391,7 +391,7 @@ static int show_available_vars_at(int fd, struct perf_probe_event *pev,
return -EINVAL;
pr_debug("Searching variables at %s\n", buf);
ret = find_available_vars_at(fd, pev, &vls, max_vls);
ret = find_available_vars_at(fd, pev, &vls, max_vls, externs);
if (ret > 0) {
/* Some variables were found */
fprintf(stdout, "Available variables at %s\n", buf);
......@@ -421,7 +421,7 @@ static int show_available_vars_at(int fd, struct perf_probe_event *pev,
/* Show available variables on given probe point */
int show_available_vars(struct perf_probe_event *pevs, int npevs,
int max_vls)
int max_vls, bool externs)
{
int i, fd, ret = 0;
......@@ -438,7 +438,7 @@ int show_available_vars(struct perf_probe_event *pevs, int npevs,
setup_pager();
for (i = 0; i < npevs && ret >= 0; i++)
ret = show_available_vars_at(fd, &pevs[i], max_vls);
ret = show_available_vars_at(fd, &pevs[i], max_vls, externs);
close(fd);
return ret;
......
......@@ -122,7 +122,7 @@ extern int del_perf_probe_events(struct strlist *dellist);
extern int show_perf_probe_events(void);
extern int show_line_range(struct line_range *lr);
extern int show_available_vars(struct perf_probe_event *pevs, int npevs,
int max_probe_points);
int max_probe_points, bool externs);
/* Maximum index number of event-name postfix */
......
......@@ -1312,12 +1312,13 @@ static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
af->pf.fb_ops, NULL);
if (ret == 0) {
ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
pr_debug2("Add new var: %s\n", buf);
if (ret > 0)
strlist__add(vl->vars, buf);
}
}
if (dwarf_haspc(die_mem, af->pf.addr))
if (af->child && dwarf_haspc(die_mem, af->pf.addr))
return DIE_FIND_CB_CONTINUE;
else
return DIE_FIND_CB_SIBLING;
......@@ -1329,8 +1330,8 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
struct available_var_finder *af =
container_of(pf, struct available_var_finder, pf);
struct variable_list *vl;
Dwarf_Die die_mem;
int ret;
Dwarf_Die die_mem, *scopes = NULL;
int ret, nscopes;
/* Check number of tevs */
if (af->nvls == af->max_vls) {
......@@ -1351,8 +1352,22 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
vl->vars = strlist__new(true, NULL);
if (vl->vars == NULL)
return -ENOMEM;
af->child = true;
die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);
/* Find external variables */
if (!af->externs)
goto out;
/* Don't need to search child DIE for externs. */
af->child = false;
nscopes = dwarf_getscopes_die(sp_die, &scopes);
while (nscopes-- > 1)
die_find_child(&scopes[nscopes], collect_variables_cb,
(void *)af, &die_mem);
if (scopes)
free(scopes);
out:
if (strlist__empty(vl->vars)) {
strlist__delete(vl->vars);
vl->vars = NULL;
......@@ -1363,11 +1378,12 @@ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
/* Find available variables at given probe point */
int find_available_vars_at(int fd, struct perf_probe_event *pev,
struct variable_list **vls, int max_vls)
struct variable_list **vls, int max_vls,
bool externs)
{
struct available_var_finder af = {
.pf = {.pev = pev, .callback = add_available_vars},
.max_vls = max_vls};
.max_vls = max_vls, .externs = externs};
int ret;
/* Allocate result vls array */
......
......@@ -30,7 +30,8 @@ extern int find_line_range(int fd, struct line_range *lr);
/* Find available variables */
extern int find_available_vars_at(int fd, struct perf_probe_event *pev,
struct variable_list **vls, int max_points);
struct variable_list **vls, int max_points,
bool externs);
#include <dwarf.h>
#include <libdw.h>
......@@ -70,6 +71,8 @@ struct available_var_finder {
struct variable_list *vls; /* Found variable lists */
int nvls; /* Number of variable lists */
int max_vls; /* Max no. of variable lists */
bool externs; /* Find external vars too */
bool child; /* Search child scopes */
};
struct line_finder {
......
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