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Subject[tip:perf/urgent] perf probe: Show accessible local variables
Commit-ID:  cf6eb489e5c04c8f8d5fd7bf90b8346c987688bc
Gitweb: http://git.kernel.org/tip/cf6eb489e5c04c8f8d5fd7bf90b8346c987688bc
Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 21 Oct 2010 19:13:23 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 21 Oct 2010 15:59:06 -0200

perf probe: Show accessible local variables

Add -V (--vars) option for listing accessible local variables at given probe
point. This will help finding which local variables are available for event
arguments.

e.g.)
# perf probe -V call_timer_fn:23
Available variables at call_timer_fn:23
@<run_timer_softirq+345>
function_type* fn
int preempt_count
long unsigned int data
struct list_head work_list
struct list_head* head
struct timer_list* timer
struct tvec_base* base

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: <20101021101323.3542.40282.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/Documentation/perf-probe.txt | 7 +
tools/perf/builtin-probe.c | 61 ++++-
tools/perf/util/probe-event.c | 72 ++++++
tools/perf/util/probe-event.h | 8 +
tools/perf/util/probe-finder.c | 412 ++++++++++++++++++++++++-------
tools/perf/util/probe-finder.h | 25 ++-
6 files changed, 480 insertions(+), 105 deletions(-)
diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 27d52da..72f5d9e 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -17,6 +17,8 @@ or
'perf probe' --list
or
'perf probe' --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]'
+or
+'perf probe' --vars='PROBEPOINT'

DESCRIPTION
-----------
@@ -57,6 +59,11 @@ OPTIONS
Show source code lines which can be probed. This needs an argument
which specifies a range of the source code. (see LINE SYNTAX for detail)

+-V::
+--vars=::
+ Show available local variables at given probe point. The argument
+ syntax is same as PROBE SYNTAX, but NO ARGs.
+
-f::
--force::
Forcibly add events with existing name.
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 199d5e1..91bb6cf 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -50,6 +50,8 @@ static struct {
bool list_events;
bool force_add;
bool show_lines;
+ bool show_vars;
+ bool mod_events;
int nevents;
struct perf_probe_event events[MAX_PROBES];
struct strlist *dellist;
@@ -57,7 +59,6 @@ static struct {
int max_probe_points;
} params;

-
/* Parse an event definition. Note that any error must die. */
static int parse_probe_event(const char *str)
{
@@ -92,6 +93,7 @@ static int parse_probe_event_argv(int argc, const char **argv)
len = 0;
for (i = 0; i < argc; i++)
len += sprintf(&buf[len], "%s ", argv[i]);
+ params.mod_events = true;
ret = parse_probe_event(buf);
free(buf);
return ret;
@@ -100,9 +102,10 @@ static int parse_probe_event_argv(int argc, const char **argv)
static int opt_add_probe_event(const struct option *opt __used,
const char *str, int unset __used)
{
- if (str)
+ if (str) {
+ params.mod_events = true;
return parse_probe_event(str);
- else
+ } else
return 0;
}

@@ -110,6 +113,7 @@ static int opt_del_probe_event(const struct option *opt __used,
const char *str, int unset __used)
{
if (str) {
+ params.mod_events = true;
if (!params.dellist)
params.dellist = strlist__new(true, NULL);
strlist__add(params.dellist, str);
@@ -130,6 +134,25 @@ static int opt_show_lines(const struct option *opt __used,

return ret;
}
+
+static int opt_show_vars(const struct option *opt __used,
+ const char *str, int unset __used)
+{
+ struct perf_probe_event *pev = &params.events[params.nevents];
+ int ret;
+
+ if (!str)
+ return 0;
+
+ ret = parse_probe_event(str);
+ if (!ret && pev->nargs != 0) {
+ pr_err(" Error: '--vars' doesn't accept arguments.\n");
+ return -EINVAL;
+ }
+ params.show_vars = true;
+
+ return ret;
+}
#endif

static const char * const probe_usage[] = {
@@ -139,6 +162,7 @@ static const char * const probe_usage[] = {
"perf probe --list",
#ifdef DWARF_SUPPORT
"perf probe --line 'LINEDESC'",
+ "perf probe --vars 'PROBEPOINT'",
#endif
NULL
};
@@ -180,6 +204,9 @@ static const struct option options[] = {
OPT_CALLBACK('L', "line", NULL,
"FUNC[:RLN[+NUM|-RLN2]]|SRC:ALN[+NUM|-ALN2]",
"Show source code lines.", opt_show_lines),
+ OPT_CALLBACK('V', "vars", NULL,
+ "FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT",
+ "Show accessible variables on PROBEDEF", opt_show_vars),
OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
"file", "vmlinux pathname"),
OPT_STRING('s', "source", &symbol_conf.source_prefix,
@@ -217,7 +244,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
usage_with_options(probe_usage, options);

if (params.list_events) {
- if (params.nevents != 0 || params.dellist) {
+ if (params.mod_events) {
pr_err(" Error: Don't use --list with --add/--del.\n");
usage_with_options(probe_usage, options);
}
@@ -225,6 +252,10 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
pr_err(" Error: Don't use --list with --line.\n");
usage_with_options(probe_usage, options);
}
+ if (params.show_vars) {
+ pr_err(" Error: Don't use --list with --vars.\n");
+ usage_with_options(probe_usage, options);
+ }
ret = show_perf_probe_events();
if (ret < 0)
pr_err(" Error: Failed to show event list. (%d)\n",
@@ -234,9 +265,13 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)

#ifdef DWARF_SUPPORT
if (params.show_lines) {
- if (params.nevents != 0 || params.dellist) {
- pr_warning(" Error: Don't use --line with"
- " --add/--del.\n");
+ if (params.mod_events) {
+ pr_err(" Error: Don't use --line with"
+ " --add/--del.\n");
+ usage_with_options(probe_usage, options);
+ }
+ if (params.show_vars) {
+ pr_err(" Error: Don't use --line with --vars.\n");
usage_with_options(probe_usage, options);
}

@@ -245,6 +280,18 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
pr_err(" Error: Failed to show lines. (%d)\n", ret);
return ret;
}
+ if (params.show_vars) {
+ if (params.mod_events) {
+ pr_err(" Error: Don't use --vars with"
+ " --add/--del.\n");
+ usage_with_options(probe_usage, options);
+ }
+ ret = show_available_vars(params.events, params.nevents,
+ params.max_probe_points);
+ if (ret < 0)
+ pr_err(" Error: Failed to show vars. (%d)\n", ret);
+ return ret;
+ }
#endif

if (params.dellist) {
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index fcc16e4..288ebe8 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -378,6 +378,72 @@ end:
return ret;
}

+static int show_available_vars_at(int fd, struct perf_probe_event *pev,
+ int max_vls)
+{
+ char *buf;
+ int ret, i;
+ struct str_node *node;
+ struct variable_list *vls = NULL, *vl;
+
+ buf = synthesize_perf_probe_point(&pev->point);
+ if (!buf)
+ return -EINVAL;
+ pr_debug("Searching variables at %s\n", buf);
+
+ ret = find_available_vars_at(fd, pev, &vls, max_vls);
+ if (ret > 0) {
+ /* Some variables were found */
+ fprintf(stdout, "Available variables at %s\n", buf);
+ for (i = 0; i < ret; i++) {
+ vl = &vls[i];
+ /*
+ * A probe point might be converted to
+ * several trace points.
+ */
+ fprintf(stdout, "\t@<%s+%lu>\n", vl->point.symbol,
+ vl->point.offset);
+ free(vl->point.symbol);
+ if (vl->vars) {
+ strlist__for_each(node, vl->vars)
+ fprintf(stdout, "\t\t%s\n", node->s);
+ strlist__delete(vl->vars);
+ } else
+ fprintf(stdout, "(No variables)\n");
+ }
+ free(vls);
+ } else
+ pr_err("Failed to find variables at %s (%d)\n", buf, ret);
+
+ free(buf);
+ return ret;
+}
+
+/* Show available variables on given probe point */
+int show_available_vars(struct perf_probe_event *pevs, int npevs,
+ int max_vls)
+{
+ int i, fd, ret = 0;
+
+ ret = init_vmlinux();
+ if (ret < 0)
+ return ret;
+
+ fd = open_vmlinux();
+ if (fd < 0) {
+ pr_warning("Failed to open debuginfo file.\n");
+ return fd;
+ }
+
+ setup_pager();
+
+ for (i = 0; i < npevs && ret >= 0; i++)
+ ret = show_available_vars_at(fd, &pevs[i], max_vls);
+
+ close(fd);
+ return ret;
+}
+
#else /* !DWARF_SUPPORT */

static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
@@ -409,6 +475,12 @@ int show_line_range(struct line_range *lr __unused)
return -ENOSYS;
}

+int show_available_vars(struct perf_probe_event *pevs __unused,
+ int npevs __unused, int max_probe_points __unused)
+{
+ pr_warning("Debuginfo-analysis is not supported.\n");
+ return -ENOSYS;
+}
#endif

int parse_line_range_desc(const char *arg, struct line_range *lr)
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 5af3924..727a7fe 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -90,6 +90,12 @@ struct line_range {
struct list_head line_list; /* Visible lines */
};

+/* List of variables */
+struct variable_list {
+ struct probe_trace_point point; /* Actual probepoint */
+ struct strlist *vars; /* Available variables */
+};
+
/* Command string to events */
extern int parse_perf_probe_command(const char *cmd,
struct perf_probe_event *pev);
@@ -115,6 +121,8 @@ extern int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,
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);


/* Maximum index number of event-name postfix */
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index c6fe80e..986027f 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -172,8 +172,8 @@ static Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
return NULL;
}

-/* Get type die, but skip qualifiers and typedef */
-static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
+/* Get a type die, but skip qualifiers */
+static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
int tag;

@@ -185,8 +185,17 @@ static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
} while (tag == DW_TAG_const_type ||
tag == DW_TAG_restrict_type ||
tag == DW_TAG_volatile_type ||
- tag == DW_TAG_shared_type ||
- tag == DW_TAG_typedef);
+ tag == DW_TAG_shared_type);
+
+ return vr_die;
+}
+
+/* Get a type die, but skip qualifiers and typedef */
+static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
+{
+ do {
+ vr_die = __die_get_real_type(vr_die, die_mem);
+ } while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);

return vr_die;
}
@@ -380,6 +389,60 @@ static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
die_mem);
}

+/* Get the name of given variable DIE */
+static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
+{
+ Dwarf_Die type;
+ int tag, ret, ret2;
+ const char *tmp = "";
+
+ if (__die_get_real_type(vr_die, &type) == NULL)
+ return -ENOENT;
+
+ tag = dwarf_tag(&type);
+ if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
+ tmp = "*";
+ else if (tag == DW_TAG_subroutine_type) {
+ /* Function pointer */
+ ret = snprintf(buf, len, "(function_type)");
+ return (ret >= len) ? -E2BIG : ret;
+ } else {
+ if (!dwarf_diename(&type))
+ return -ENOENT;
+ if (tag == DW_TAG_union_type)
+ tmp = "union ";
+ else if (tag == DW_TAG_structure_type)
+ tmp = "struct ";
+ /* Write a base name */
+ ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
+ return (ret >= len) ? -E2BIG : ret;
+ }
+ ret = die_get_typename(&type, buf, len);
+ if (ret > 0) {
+ ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
+ ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
+ }
+ return ret;
+}
+
+/* Get the name and type of given variable DIE, stored as "type\tname" */
+static int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
+{
+ int ret, ret2;
+
+ ret = die_get_typename(vr_die, buf, len);
+ if (ret < 0) {
+ pr_debug("Failed to get type, make it unknown.\n");
+ ret = snprintf(buf, len, "(unknown_type)");
+ }
+ if (ret > 0) {
+ ret2 = snprintf(buf + ret, len - ret, "\t%s",
+ dwarf_diename(vr_die));
+ ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
+ }
+ return ret;
+}
+
/*
* Probe finder related functions
*/
@@ -393,8 +456,13 @@ static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
return ref;
}

-/* Show a location */
-static int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
+/*
+ * Convert a location into trace_arg.
+ * If tvar == NULL, this just checks variable can be converted.
+ */
+static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
+ Dwarf_Op *fb_ops,
+ struct probe_trace_arg *tvar)
{
Dwarf_Attribute attr;
Dwarf_Op *op;
@@ -403,7 +471,6 @@ static int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
Dwarf_Word offs = 0;
bool ref = false;
const char *regs;
- struct probe_trace_arg *tvar = pf->tvar;
int ret;

if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
@@ -411,16 +478,16 @@ static int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)

/* TODO: handle more than 1 exprs */
if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
- dwarf_getlocation_addr(&attr, pf->addr, &op, &nops, 1) <= 0 ||
+ dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
nops == 0) {
/* TODO: Support const_value */
- pr_err("Failed to find the location of %s at this address.\n"
- " Perhaps, it has been optimized out.\n", pf->pvar->var);
return -ENOENT;
}

if (op->atom == DW_OP_addr) {
static_var:
+ if (!tvar)
+ return 0;
/* Static variables on memory (not stack), make @varname */
ret = strlen(dwarf_diename(vr_die));
tvar->value = zalloc(ret + 2);
@@ -435,14 +502,11 @@ static_var:

/* If this is based on frame buffer, set the offset */
if (op->atom == DW_OP_fbreg) {
- if (pf->fb_ops == NULL) {
- pr_warning("The attribute of frame base is not "
- "supported.\n");
+ if (fb_ops == NULL)
return -ENOTSUP;
- }
ref = true;
offs = op->number;
- op = &pf->fb_ops[0];
+ op = &fb_ops[0];
}

if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
@@ -458,13 +522,18 @@ static_var:
} else if (op->atom == DW_OP_regx) {
regn = op->number;
} else {
- pr_warning("DW_OP %x is not supported.\n", op->atom);
+ pr_debug("DW_OP %x is not supported.\n", op->atom);
return -ENOTSUP;
}

+ if (!tvar)
+ return 0;
+
regs = get_arch_regstr(regn);
if (!regs) {
- pr_warning("Mapping for DWARF register number %u missing on this architecture.", regn);
+ /* This should be a bug in DWARF or this tool */
+ pr_warning("Mapping for DWARF register number %u "
+ "missing on this architecture.", regn);
return -ERANGE;
}

@@ -689,8 +758,14 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
pr_debug("Converting variable %s into trace event.\n",
dwarf_diename(vr_die));

- ret = convert_variable_location(vr_die, pf);
- if (ret == 0 && pf->pvar->field) {
+ ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
+ pf->tvar);
+ if (ret == -ENOENT)
+ pr_err("Failed to find the location of %s at this address.\n"
+ " Perhaps, it has been optimized out.\n", pf->pvar->var);
+ else if (ret == -ENOTSUP)
+ pr_err("Sorry, we don't support this variable location yet.\n");
+ else if (pf->pvar->field) {
ret = convert_variable_fields(vr_die, pf->pvar->var,
pf->pvar->field, &pf->tvar->ref,
&die_mem);
@@ -772,34 +847,12 @@ found:
return ret;
}

-/* Show a probe point to output buffer */
-static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
+/* Convert subprogram DIE to trace point */
+static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
+ bool retprobe, struct probe_trace_point *tp)
{
- struct probe_trace_event *tev;
Dwarf_Addr eaddr;
- Dwarf_Die die_mem;
const char *name;
- int ret, i;
- Dwarf_Attribute fb_attr;
- size_t nops;
-
- if (pf->ntevs == pf->max_tevs) {
- pr_warning("Too many( > %d) probe point found.\n",
- pf->max_tevs);
- return -ERANGE;
- }
- tev = &pf->tevs[pf->ntevs++];
-
- /* If no real subprogram, find a real one */
- if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
- sp_die = die_find_real_subprogram(&pf->cu_die,
- pf->addr, &die_mem);
- if (!sp_die) {
- pr_warning("Failed to find probe point in any "
- "functions.\n");
- return -ENOENT;
- }
- }

/* Copy the name of probe point */
name = dwarf_diename(sp_die);
@@ -809,26 +862,45 @@ static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
dwarf_diename(sp_die));
return -ENOENT;
}
- tev->point.symbol = strdup(name);
- if (tev->point.symbol == NULL)
+ tp->symbol = strdup(name);
+ if (tp->symbol == NULL)
return -ENOMEM;
- tev->point.offset = (unsigned long)(pf->addr - eaddr);
+ tp->offset = (unsigned long)(paddr - eaddr);
} else
/* This function has no name. */
- tev->point.offset = (unsigned long)pf->addr;
+ tp->offset = (unsigned long)paddr;

/* Return probe must be on the head of a subprogram */
- if (pf->pev->point.retprobe) {
- if (tev->point.offset != 0) {
+ if (retprobe) {
+ if (eaddr != paddr) {
pr_warning("Return probe must be on the head of"
" a real function\n");
return -EINVAL;
}
- tev->point.retprobe = true;
+ tp->retprobe = true;
}

- pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
- tev->point.offset);
+ return 0;
+}
+
+/* Call probe_finder callback with real subprogram DIE */
+static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
+{
+ Dwarf_Die die_mem;
+ Dwarf_Attribute fb_attr;
+ size_t nops;
+ int ret;
+
+ /* If no real subprogram, find a real one */
+ if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
+ sp_die = die_find_real_subprogram(&pf->cu_die,
+ pf->addr, &die_mem);
+ if (!sp_die) {
+ pr_warning("Failed to find probe point in any "
+ "functions.\n");
+ return -ENOENT;
+ }
+ }

/* Get the frame base attribute/ops */
dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
@@ -848,22 +920,13 @@ static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
#endif
}

- /* Find each argument */
- tev->nargs = pf->pev->nargs;
- tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
- if (tev->args == NULL)
- return -ENOMEM;
- for (i = 0; i < pf->pev->nargs; i++) {
- pf->pvar = &pf->pev->args[i];
- pf->tvar = &tev->args[i];
- ret = find_variable(sp_die, pf);
- if (ret != 0)
- return ret;
- }
+ /* Call finder's callback handler */
+ ret = pf->callback(sp_die, pf);

/* *pf->fb_ops will be cached in libdw. Don't free it. */
pf->fb_ops = NULL;
- return 0;
+
+ return ret;
}

/* Find probe point from its line number */
@@ -899,7 +962,7 @@ static int find_probe_point_by_line(struct probe_finder *pf)
(int)i, lineno, (uintmax_t)addr);
pf->addr = addr;

- ret = convert_probe_point(NULL, pf);
+ ret = call_probe_finder(NULL, pf);
/* Continuing, because target line might be inlined. */
}
return ret;
@@ -1012,7 +1075,7 @@ static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
(int)i, lineno, (unsigned long long)addr);
pf->addr = addr;

- ret = convert_probe_point(sp_die, pf);
+ ret = call_probe_finder(sp_die, pf);
/* Continuing, because target line might be inlined. */
}
/* TODO: deallocate lines, but how? */
@@ -1047,7 +1110,7 @@ static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
pr_debug("found inline addr: 0x%jx\n",
(uintmax_t)pf->addr);

- param->retval = convert_probe_point(in_die, pf);
+ param->retval = call_probe_finder(in_die, pf);
if (param->retval < 0)
return DWARF_CB_ABORT;
}
@@ -1085,7 +1148,7 @@ static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
}
pf->addr += pp->offset;
/* TODO: Check the address in this function */
- param->retval = convert_probe_point(sp_die, pf);
+ param->retval = call_probe_finder(sp_die, pf);
}
} else {
struct dwarf_callback_param _param = {.data = (void *)pf,
@@ -1107,70 +1170,229 @@ static int find_probe_point_by_func(struct probe_finder *pf)
return _param.retval;
}

-/* Find probe_trace_events specified by perf_probe_event from debuginfo */
-int find_probe_trace_events(int fd, struct perf_probe_event *pev,
- struct probe_trace_event **tevs, int max_tevs)
+/* Find probe points from debuginfo */
+static int find_probes(int fd, struct probe_finder *pf)
{
- struct probe_finder pf = {.pev = pev, .max_tevs = max_tevs};
- struct perf_probe_point *pp = &pev->point;
+ struct perf_probe_point *pp = &pf->pev->point;
Dwarf_Off off, noff;
size_t cuhl;
Dwarf_Die *diep;
Dwarf *dbg;
int ret = 0;

- pf.tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
- if (pf.tevs == NULL)
- return -ENOMEM;
- *tevs = pf.tevs;
- pf.ntevs = 0;
-
dbg = dwarf_begin(fd, DWARF_C_READ);
if (!dbg) {
pr_warning("No dwarf info found in the vmlinux - "
"please rebuild with CONFIG_DEBUG_INFO=y.\n");
- free(pf.tevs);
- *tevs = NULL;
return -EBADF;
}

#if _ELFUTILS_PREREQ(0, 142)
/* Get the call frame information from this dwarf */
- pf.cfi = dwarf_getcfi(dbg);
+ pf->cfi = dwarf_getcfi(dbg);
#endif

off = 0;
- line_list__init(&pf.lcache);
+ line_list__init(&pf->lcache);
/* Loop on CUs (Compilation Unit) */
while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
ret >= 0) {
/* Get the DIE(Debugging Information Entry) of this CU */
- diep = dwarf_offdie(dbg, off + cuhl, &pf.cu_die);
+ diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die);
if (!diep)
continue;

/* Check if target file is included. */
if (pp->file)
- pf.fname = cu_find_realpath(&pf.cu_die, pp->file);
+ pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
else
- pf.fname = NULL;
+ pf->fname = NULL;

- if (!pp->file || pf.fname) {
+ if (!pp->file || pf->fname) {
if (pp->function)
- ret = find_probe_point_by_func(&pf);
+ ret = find_probe_point_by_func(pf);
else if (pp->lazy_line)
- ret = find_probe_point_lazy(NULL, &pf);
+ ret = find_probe_point_lazy(NULL, pf);
else {
- pf.lno = pp->line;
- ret = find_probe_point_by_line(&pf);
+ pf->lno = pp->line;
+ ret = find_probe_point_by_line(pf);
}
}
off = noff;
}
- line_list__free(&pf.lcache);
+ line_list__free(&pf->lcache);
dwarf_end(dbg);

- return (ret < 0) ? ret : pf.ntevs;
+ return ret;
+}
+
+/* Add a found probe point into trace event list */
+static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
+{
+ struct trace_event_finder *tf =
+ container_of(pf, struct trace_event_finder, pf);
+ struct probe_trace_event *tev;
+ int ret, i;
+
+ /* Check number of tevs */
+ if (tf->ntevs == tf->max_tevs) {
+ pr_warning("Too many( > %d) probe point found.\n",
+ tf->max_tevs);
+ return -ERANGE;
+ }
+ tev = &tf->tevs[tf->ntevs++];
+
+ ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
+ &tev->point);
+ if (ret < 0)
+ return ret;
+
+ 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)
+ return -ENOMEM;
+ for (i = 0; i < pf->pev->nargs; i++) {
+ pf->pvar = &pf->pev->args[i];
+ pf->tvar = &tev->args[i];
+ ret = find_variable(sp_die, pf);
+ if (ret != 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+/* Find probe_trace_events specified by perf_probe_event from debuginfo */
+int find_probe_trace_events(int fd, struct perf_probe_event *pev,
+ struct probe_trace_event **tevs, int max_tevs)
+{
+ struct trace_event_finder tf = {
+ .pf = {.pev = pev, .callback = add_probe_trace_event},
+ .max_tevs = max_tevs};
+ int ret;
+
+ /* Allocate result tevs array */
+ *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
+ if (*tevs == NULL)
+ return -ENOMEM;
+
+ tf.tevs = *tevs;
+ tf.ntevs = 0;
+
+ ret = find_probes(fd, &tf.pf);
+ if (ret < 0) {
+ free(*tevs);
+ *tevs = NULL;
+ return ret;
+ }
+
+ return (ret < 0) ? ret : tf.ntevs;
+}
+
+#define MAX_VAR_LEN 64
+
+/* Collect available variables in this scope */
+static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
+{
+ struct available_var_finder *af = data;
+ struct variable_list *vl;
+ char buf[MAX_VAR_LEN];
+ int tag, ret;
+
+ vl = &af->vls[af->nvls - 1];
+
+ tag = dwarf_tag(die_mem);
+ if (tag == DW_TAG_formal_parameter ||
+ tag == DW_TAG_variable) {
+ ret = convert_variable_location(die_mem, af->pf.addr,
+ af->pf.fb_ops, NULL);
+ if (ret == 0) {
+ ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
+ if (ret > 0)
+ strlist__add(vl->vars, buf);
+ }
+ }
+
+ if (dwarf_haspc(die_mem, af->pf.addr))
+ return DIE_FIND_CB_CONTINUE;
+ else
+ return DIE_FIND_CB_SIBLING;
+}
+
+/* Add a found vars into available variables list */
+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;
+
+ /* Check number of tevs */
+ if (af->nvls == af->max_vls) {
+ pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
+ return -ERANGE;
+ }
+ vl = &af->vls[af->nvls++];
+
+ ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
+ &vl->point);
+ if (ret < 0)
+ return ret;
+
+ pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
+ vl->point.offset);
+
+ /* Find local variables */
+ vl->vars = strlist__new(true, NULL);
+ if (vl->vars == NULL)
+ return -ENOMEM;
+ die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);
+
+ if (strlist__empty(vl->vars)) {
+ strlist__delete(vl->vars);
+ vl->vars = NULL;
+ }
+
+ return ret;
+}
+
+/* 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 available_var_finder af = {
+ .pf = {.pev = pev, .callback = add_available_vars},
+ .max_vls = max_vls};
+ int ret;
+
+ /* Allocate result vls array */
+ *vls = zalloc(sizeof(struct variable_list) * max_vls);
+ if (*vls == NULL)
+ return -ENOMEM;
+
+ af.vls = *vls;
+ af.nvls = 0;
+
+ ret = find_probes(fd, &af.pf);
+ if (ret < 0) {
+ /* Free vlist for error */
+ while (af.nvls--) {
+ if (af.vls[af.nvls].point.symbol)
+ free(af.vls[af.nvls].point.symbol);
+ if (af.vls[af.nvls].vars)
+ strlist__delete(af.vls[af.nvls].vars);
+ }
+ free(af.vls);
+ *vls = NULL;
+ return ret;
+ }
+
+ return (ret < 0) ? ret : af.nvls;
}

/* Reverse search */
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 4507d51..baffd25 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -25,17 +25,22 @@ extern int find_probe_trace_events(int fd, struct perf_probe_event *pev,
extern int find_perf_probe_point(int fd, unsigned long addr,
struct perf_probe_point *ppt);

+/* Find a line range */
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);
+
#include <dwarf.h>
#include <libdw.h>
#include <version.h>

struct probe_finder {
struct perf_probe_event *pev; /* Target probe event */
- struct probe_trace_event *tevs; /* Result trace events */
- int ntevs; /* Number of trace events */
- int max_tevs; /* Max number of trace events */
+
+ /* Callback when a probe point is found */
+ int (*callback)(Dwarf_Die *sp_die, struct probe_finder *pf);

/* For function searching */
int lno; /* Line number */
@@ -53,6 +58,20 @@ struct probe_finder {
struct probe_trace_arg *tvar; /* Current result variable */
};

+struct trace_event_finder {
+ struct probe_finder pf;
+ struct probe_trace_event *tevs; /* Found trace events */
+ int ntevs; /* Number of trace events */
+ int max_tevs; /* Max number of trace events */
+};
+
+struct available_var_finder {
+ struct probe_finder pf;
+ struct variable_list *vls; /* Found variable lists */
+ int nvls; /* Number of variable lists */
+ int max_vls; /* Max no. of variable lists */
+};
+
struct line_finder {
struct line_range *lr; /* Target line range */


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