Debug code enabled on Systemtap verison: 0.8?

["Buddy Lumpkin" <buddy dot lumpkin at gmail dot com>]

Sorry if this is a duplicate, I already sent this once to
systemtap@sourceware.org, re-sending to systemtap@sources.redhat.com.

I have a guru mode script that uses a combination of the systemtap
language and inline C. Upon upgrading to systemtap 0.8, I noticed an
extra message being printed from my scripts output. I assume it is
extra debugging of the code interpreter?

This is the extra line that is printed:

node_addr=0x0

There is a global variable called node_addr in my script. A small
adjustment to some code made the message go away:


this causes the message to occur:

           if ((node_addr = node_addr(node_id + 1)))
           {
               node_id++;
               pg_index = 0;
               mem_map = node_mem_map(node_id);
               present_pages = node_present_pages(node_id);
           }

Written this way, it goes away:

           node_addr = node_addr(node_id + 1);
           if (node_addr)
           {
               node_id++;
               pg_index = 0;
               mem_map = node_mem_map(node_id);
               present_pages = node_present_pages(node_id);
           }

Here is what appears to be the relevant portion of a unified diff of
the code that is produced:


@@ -3696,26 +3701,24 @@
            global.s_pages_scanned;
          });

-          (void)
-          ({
-            l->__tmp80 =
-            ({
-              l->__tmp82 = ((global.s_node_id) + (((int64_t)1LL)));
-              c->locals[c->nesting+1].function_node_addr.node_idx = l->__tmp82;
-              function_node_addr (c);
-              if (unlikely(c->last_error)) goto out;
-              c->locals[c->nesting+1].function_node_addr.__retvalue;
-            });
-            global.s_node_addr = l->__tmp80;
-            l->__tmp80;
-          });
-
-          c->actionremaining -= 3;
+          c->actionremaining -= 2;
          if (unlikely (c->actionremaining <= 0)) {
            c->last_error = "MAXACTION exceeded";
            goto out;
          }
-          if (global.s_node_addr) {
+          if (
+            ({
+              l->__tmp80 =
+              ({
+                l->__tmp82 = ((global.s_node_id) + (((int64_t)1LL)));
+                c->locals[c->nesting+1].function_node_addr.node_idx =
l->__tmp82;
+                function_node_addr (c);
+                if (unlikely(c->last_error)) goto out;
+                c->locals[c->nesting+1].function_node_addr.__retvalue;
+              });
+              global.s_node_addr = l->__tmp80;
+              l->__tmp80;
+            })) {
            {
              (void)
              ({
@@ -3949,6 +3952,36 @@
 }


+#ifdef STP_TIMING
+static __cacheline_aligned Stat time_probe_1405;
+#endif
+
+static void probe_1406 (struct context * __restrict__ c) {
+  struct probe_1406_locals * __restrict__ l =
+    & c->locals[0].probe_1406;
+  (void) l;
+  #ifdef STP_TIMING
+  c->statp = & time_probe_1405;
+  #endif
+  {
+    (void)
+    ({
+      l->__tmp0 = global.s_node_addr;
+      _stp_printf ("node_addr=%#llx\n", l->__tmp0);
+      ((int64_t)0LL);
+    });
+
+  }
+  c->actionremaining -= 1;
+  if (unlikely (c->actionremaining <= 0)) {
+    c->last_error = "MAXACTION exceeded";
+    goto out;
+  }
+out:
+  _stp_print_flush();
+}
+
+
 /* ---- begin/end probes ---- */
 void enter_begin_probe (void (*fn)(struct context*), const char* pp) {
  struct context* __restrict__ c;
@@ -4161,6 +4194,7 @@
 } stap_be_probes[] = {
  { .pp="begin", .ph=&probe_1402, .type=0 },
  { .pp="end", .ph=&probe_1404, .type=1 },
+  { .pp="end", .ph=&probe_1406, .type=1 },
 };