perf probe: Support argument name

Set given names to event arguments. The syntax is same as kprobe-tracer,
you can add 'NAME=' right before each argument.

e.g.
  ./perf probe vfs_read foo=file

 then, 'foo' is set to the argument name as below.

  ./perf probe -l
  probe:vfs_read       (on vfs_read@linux-2.6-tip/fs/read_write.c with foo)

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: <20100412171653.3790.74624.stgit@localhost6.localdomain6>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 16 insertions, 11 deletions

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index a8513772df08..105e95c95eeb 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -484,35 +484,40 @@ static void convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
         convert_location(expr, pf);
 
         if (pf->pvar->field)
-                convert_variable_fields(vr_die, pf->pvar->name,
+                convert_variable_fields(vr_die, pf->pvar->var,
                                         pf->pvar->field, &pf->tvar->ref);
         /* *expr will be cached in libdw. Don't free it. */
         return ;
 error:
         /* TODO: Support const_value */
         die("Failed to find the location of %s at this address.\n"
-            " Perhaps, it has been optimized out.", pf->pvar->name);
+            " Perhaps, it has been optimized out.", pf->pvar->var);
 }
 
 /* Find a variable in a subprogram die */
 static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 {
         Dwarf_Die vr_die;
-        char buf[128];
+        char buf[32];
 
-        /* TODO: Support struct members and arrays */
-        if (!is_c_varname(pf->pvar->name)) {
+        /* TODO: Support arrays */
+        if (pf->pvar->name)
+                pf->tvar->name = xstrdup(pf->pvar->name);
+        else {
+                synthesize_perf_probe_arg(pf->pvar, buf, 32);
+                pf->tvar->name = xstrdup(buf);
+        }
+
+        if (!is_c_varname(pf->pvar->var)) {
                 /* Copy raw parameters */
-                pf->tvar->value = xstrdup(pf->pvar->name);
+                pf->tvar->value = xstrdup(pf->pvar->var);
         } else {
-                synthesize_perf_probe_arg(pf->pvar, buf, 128);
-                pf->tvar->name = xstrdup(buf);
                 pr_debug("Searching '%s' variable in context.\n",
-                         pf->pvar->name);
+                         pf->pvar->var);
                 /* Search child die for local variables and parameters. */
-                if (!die_find_variable(sp_die, pf->pvar->name, &vr_die))
+                if (!die_find_variable(sp_die, pf->pvar->var, &vr_die))
                         die("Failed to find '%s' in this function.",
-                            pf->pvar->name);
+                            pf->pvar->var);
                 convert_variable(&vr_die, pf);
         }
 }