perf probe: Support basic type casting
Add basic type casting for arguments to perf probe. This allows
users to specify the actual type of arguments. Of course, if
user sets invalid types, kprobe-tracer rejects that.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100412171722.3790.50372.stgit@localhost6.localdomain6>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 441324f2..63c25d3 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -85,9 +85,10 @@
--------------
Each probe argument follows below syntax.
- [NAME=]LOCALVAR|$retval|%REG|@SYMBOL
+ [NAME=]LOCALVAR|$retval|%REG|@SYMBOL[:TYPE]
'NAME' specifies the name of this argument (optional). You can use the name of local variable, local data structure member (e.g. var->field, var.field2), or kprobe-tracer argument format (e.g. $retval, %ax, etc). Note that the name of this argument will be set as the last member name if you specify a local data structure member (e.g. field2 for 'var->field1.field2'.)
+'TYPE' casts the type of this argument (optional). If omitted, perf probe automatically set the type based on debuginfo.
LINE SYNTAX
-----------
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 05ca4a9..bef2805 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -435,7 +435,7 @@
}
/* Parse perf-probe event argument */
-static void parse_perf_probe_arg(const char *str, struct perf_probe_arg *arg)
+static void parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
{
char *tmp;
struct perf_probe_arg_field **fieldp;
@@ -445,9 +445,17 @@
tmp = strchr(str, '=');
if (tmp) {
arg->name = xstrndup(str, tmp - str);
+ pr_debug("name:%s ", arg->name);
str = tmp + 1;
}
+ tmp = strchr(str, ':');
+ if (tmp) { /* Type setting */
+ *tmp = '\0';
+ arg->type = xstrdup(tmp + 1);
+ pr_debug("type:%s ", arg->type);
+ }
+
tmp = strpbrk(str, "-.");
if (!is_c_varname(str) || !tmp) {
/* A variable, register, symbol or special value */
@@ -603,6 +611,15 @@
len -= ret;
field = field->next;
}
+
+ if (pa->type) {
+ ret = e_snprintf(tmp, len, ":%s", pa->type);
+ if (ret <= 0)
+ goto error;
+ tmp += ret;
+ len -= ret;
+ }
+
return tmp - buf;
error:
die("Failed to synthesize perf probe argument: %s", strerror(-ret));
@@ -825,6 +842,8 @@
free(pev->args[i].name);
if (pev->args[i].var)
free(pev->args[i].var);
+ if (pev->args[i].type)
+ free(pev->args[i].type);
field = pev->args[i].field;
while (field) {
next = field->next;
@@ -1145,6 +1164,8 @@
if (pev->args[i].name)
tev->args[i].name = xstrdup(pev->args[i].name);
tev->args[i].value = xstrdup(pev->args[i].var);
+ if (pev->args[i].type)
+ tev->args[i].type = xstrdup(pev->args[i].type);
}
}
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index a393a3f..ff2f26b 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -57,6 +57,7 @@
struct perf_probe_arg {
char *name; /* Argument name */
char *var; /* Variable name */
+ char *type; /* Type name */
struct perf_probe_arg_field *field; /* Structure fields */
};
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index ebeb413..ab47673 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -547,7 +547,10 @@
&die_mem);
vr_die = &die_mem;
}
- convert_variable_type(vr_die, pf->tvar);
+ if (pf->pvar->type)
+ pf->tvar->type = xstrdup(pf->pvar->type);
+ else
+ convert_variable_type(vr_die, pf->tvar);
/* *expr will be cached in libdw. Don't free it. */
return ;
error:
@@ -560,13 +563,16 @@
static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
{
Dwarf_Die vr_die;
- char buf[32];
+ char buf[32], *ptr;
/* TODO: Support arrays */
if (pf->pvar->name)
pf->tvar->name = xstrdup(pf->pvar->name);
else {
synthesize_perf_probe_arg(pf->pvar, buf, 32);
+ ptr = strchr(buf, ':'); /* Change type separator to _ */
+ if (ptr)
+ *ptr = '_';
pf->tvar->name = xstrdup(buf);
}