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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2010-10-21 19:13:23 +0900
committerArnaldo Carvalho de Melo <acme@redhat.com>2010-10-21 15:59:06 -0200
commitcf6eb489e5c04c8f8d5fd7bf90b8346c987688bc (patch)
tree3da471c3ae3f99cdcbec26cc95412a4b44506f3c /tools/perf/util/probe-finder.c
parent632941c4f8fbd5b90dcb1672cd0422dfd7332bc9 (diff)
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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>
Diffstat (limited to 'tools/perf/util/probe-finder.c')
-rw-r--r--tools/perf/util/probe-finder.c412
1 files changed, 317 insertions, 95 deletions
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index c6fe80ebb26..986027fa495 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 */