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perf probe: Show accessible local variables

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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>
This commit is contained in:
Masami Hiramatsu 2010-10-21 19:13:23 +09:00 committed by Arnaldo Carvalho de Melo
parent 632941c4f8
commit cf6eb489e5
6 changed files with 480 additions and 105 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
tools/perf/Documentation/perf-probe.txt
View file

@ -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.

61
tools/perf/builtin-probe.c
View file

@ -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) {

72
tools/perf/util/probe-event.c
View file

@ -378,6 +378,72 @@ int show_line_range(struct line_range *lr)
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)

8
tools/perf/util/probe-event.h
View file

@ -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 */

412
tools/perf/util/probe-finder.c
View file

@ -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 int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
/* 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 int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
} 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 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
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 */

25
tools/perf/util/probe-finder.h
View file

@ -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 */