Collect used library functions as reusable names for the renamer.

Implements another TODO.

There was a TODO about a new counter per scope, but that makes no sense. The renamer only acts on global variables, global function and parameter names, state names, and event parameters. We're already restarting the counters at every function, which is the closest to what that TODO was about.

lslopt/lsllastpass.py

@@ -106,6 +106,13 @@ class lastpass(object):
                 self.BadStCh = True
             return
 
+        if nt == 'FNCALL':
+            # lslrenamer can benefit from a list of used library functions,
+            # so provide it.
+            if 'Loc' not in self.symtab[0][node['name']]:
+                # system library function
+                self.usedlibfuncs.add(node['name'])
+
     def LastPassPostOrder(self, parent, index):
         node = parent[index]
         nt = node['nt']
@@ -154,11 +161,14 @@ class lastpass(object):
         self.subinfo = subinfo
 
     def LastPass(self):
+        """Last optimizations pass"""
+
         self.globalmode = False
 
         tree = self.tree
 
-        # Last optimizations pass
+        self.usedlibfuncs = set()
+
         # self.subinfo is subtree-local info.
         self.subinfo = {}
         for idx in xrange(len(tree)):
@@ -168,4 +178,4 @@ class lastpass(object):
                 self.globalmode = False
             else:
                 self.RecursiveLastPass(tree, idx)
-    pass
+        return {'libfuncs':self.usedlibfuncs}