Fix DCE for try/except and add len/random support

bootstrap/dce.py

@@ -178,11 +178,12 @@ class UsageAnalyzer:
 
         elif isinstance(stmt, TryStmt):
             self.used.add('exception')
-            self._analyze_body(stmt.try_body)
-            if stmt.except_body:
-                self._analyze_body(stmt.except_body)
-            if stmt.finally_body:
-                self._analyze_body(stmt.finally_body)
+            self._analyze_body(stmt.try_block)
+            for except_clause in stmt.except_clauses:
+                if len(except_clause) >= 2:
+                    self._analyze_body(except_clause[1])
+            if stmt.finally_block:
+                self._analyze_body(stmt.finally_block)
 
         elif isinstance(stmt, ThrowStmt):
             self.used.add('exception')
@@ -262,6 +263,11 @@ class UsageAnalyzer:
             if callee.name in self.defined_classes:
                 self.has_classes = True
                 self.used_classes.add(callee.name)
+            elif callee.name == 'len':
+                self.used.add('string')
+                self.used.add('array')
+            elif callee.name in ('random', 'random_range'):
+                self.used.add('misc')
 
         if isinstance(callee, MemberAccess):
             if isinstance(callee.object, ThisExpr):