Added entry-counts.d dtrace script for probe analysis.

Updated .gitignore to allow .d files outside of shotgun.

.gitignore

@@ -26,8 +26,9 @@ scratch
 !runtime/stable/loader.rbc
 runtime/pristine*
 runtime/platform.conf
-
-*.d
+.*.d
+shotgun/lib/*.d
+shotgun/lib/subtend/*.d
 *.o
 *.lo
 *.a

tools/dtrace/entry-counts.d

@@ -0,0 +1,19 @@
+/*
+ * entry/exit counts
+ *
+ * This script manages a counter for every method invocation. Upon function-entry the probe increments
+ * the counter, upon function-return the counter decrements the counter. At the end of the run
+ * dtrace should print all methods run, with a count of 0 for all of them - indicating that the probes
+ * have fired correctly.
+ *
+ * Example invocation:
+ *
+ * $> sudo dtrace -s entry-counts.d -c 'rbx ~/hello.rb'
+ */
+
+#pragma D option dynvarsize=250m
+#pragma D option bufsize=64m
+
+rubinius$target:::function-entry { @[copyinstr(arg0), copyinstr(arg1)] = sum(1); } 
+rubinius$target:::function-return { @[copyinstr(arg0), copyinstr(arg1)] = sum(-1); } 
+