perf tools: Handle arrays in print fields for trace parsing

The array used by the ftrace stack events (caller[x]) causes
issues with the parser. This adds code to handle the case, but
it also assumes that the array is of type long.

Note, this is a special case used (currently) only by the ftrace
user and kernel stack records.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <20091014194358.124833639@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 62 insertions, 0 deletions

diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
index 3e643f5da202..7aeedb09ea7d 100644
--- a/tools/perf/util/trace-event-parse.c
+++ b/tools/perf/util/trace-event-parse.c
@@ -1046,6 +1046,35 @@ out_free:
         return EVENT_ERROR;
 }
 
+static enum event_type
+process_array(struct event *event, struct print_arg *top, char **tok)
+{
+        struct print_arg *arg;
+        enum event_type type;
+        char *token = NULL;
+
+        arg = malloc_or_die(sizeof(*arg));
+        memset(arg, 0, sizeof(*arg));
+
+        *tok = NULL;
+        type = process_arg(event, arg, &token);
+        if (test_type_token(type, token, EVENT_OP, (char *)"]"))
+                goto out_free;
+
+        top->op.right = arg;
+
+        free_token(token);
+        type = read_token_item(&token);
+        *tok = token;
+
+        return type;
+
+out_free:
+        free_token(*tok);
+        free_arg(arg);
+        return EVENT_ERROR;
+}
+
 static int get_op_prio(char *op)
 {
         if (!op[1]) {
@@ -1192,6 +1221,18 @@ process_op(struct event *event, struct print_arg *arg, char **tok)
 
                 arg->op.right = right;
 
+        } else if (strcmp(token, "[") == 0) {
+
+                left = malloc_or_die(sizeof(*left));
+                *left = *arg;
+
+                arg->type = PRINT_OP;
+                arg->op.op = token;
+                arg->op.left = left;
+
+                arg->op.prio = 0;
+                type = process_array(event, arg, tok);
+
         } else {
                 die("unknown op '%s'", token);
                 /* the arg is now the left side */
@@ -1931,6 +1972,7 @@ static unsigned long long eval_num_arg(void *data, int size,
 {
         unsigned long long val = 0;
         unsigned long long left, right;
+        struct print_arg *larg;
 
         switch (arg->type) {
         case PRINT_NULL:
@@ -1957,6 +1999,26 @@ static unsigned long long eval_num_arg(void *data, int size,
                 return 0;
                 break;
         case PRINT_OP:
+                if (strcmp(arg->op.op, "[") == 0) {
+                        /*
+                         * Arrays are special, since we don't want
+                         * to read the arg as is.
+                         */
+                        if (arg->op.left->type != PRINT_FIELD)
+                                goto default_op; /* oops, all bets off */
+                        larg = arg->op.left;
+                        if (!larg->field.field) {
+                                larg->field.field =
+                                        find_any_field(event, larg->field.name);
+                                if (!larg->field.field)
+                                        die("field %s not found", larg->field.name);
+                        }
+                        right = eval_num_arg(data, size, event, arg->op.right);
+                        val = read_size(data + larg->field.field->offset +
+                                        right * long_size, long_size);
+                        break;
+                }
+ default_op:
                 left = eval_num_arg(data, size, event, arg->op.left);
                 right = eval_num_arg(data, size, event, arg->op.right);
                 switch (arg->op.op[0]) {