2.7 can have two JUMP_BACKs at the end of a while loop

rocky · rocky · commit bfceeac6c8a3 · 2019-01-27T21:41:17.000-05:00
Fixes rocky#215
diff --git a/test/bytecode_2.7/05_while_elif.pyc b/test/bytecode_2.7/05_while_elif.pyc
diff --git a/test/simple_source/bug27+/05_while_elif.py b/test/simple_source/bug27+/05_while_elif.py
@@ -0,0 +1,16 @@
+# Bug in Python 2.7. Bug is bytecode for while loop having
+# two consecutive JUMP_BACKS at the end of 'elif' and 'while'
+# to the same place
+def PreprocessConditionalStatement(self, IfList, ReplacedLine):
+    while self:
+        if self.__Token:
+            x = 1
+        elif not IfList:
+            if self <= 2:
+                continue
+            RegionSizeGuid = 3
+            if not RegionSizeGuid:
+                RegionLayoutLine = 5
+                continue
+            RegionLayoutLine = self.CurrentLineNumber
+    return 1
diff --git a/uncompyle6/parsers/parse27.py b/uncompyle6/parsers/parse27.py
@@ -156,7 +156,13 @@ def p_stmt27(self, args):
 
         while1stmt        ::= SETUP_LOOP returns bp_come_from
         while1stmt        ::= SETUP_LOOP l_stmts_opt JUMP_BACK POP_BLOCK COME_FROM
+
         whilestmt         ::= SETUP_LOOP testexpr l_stmts_opt JUMP_BACK POP_BLOCK _come_froms
+
+        # Should this be JUMP_BACK+ ?
+        # JUMP_BACK should all be to the same location
+        whilestmt         ::= SETUP_LOOP testexpr l_stmts_opt JUMP_BACK JUMP_BACK POP_BLOCK _come_froms
+
         while1elsestmt    ::= SETUP_LOOP l_stmts JUMP_BACK POP_BLOCK
                               else_suitel COME_FROM
         whileelsestmt     ::= SETUP_LOOP testexpr l_stmts_opt JUMP_BACK POP_BLOCK
@@ -211,14 +217,17 @@ def customize_grammar_rules(self, tokens, customize):
         self.check_reduce['list_if_not'] = 'AST'
         self.check_reduce['list_if'] = 'AST'
         self.check_reduce['conditional_true'] = 'AST'
+        self.check_reduce['whilestmt'] = 'tokens'
         return
 
     def reduce_is_invalid(self, rule, ast, tokens, first, last):
         invalid = super(Python27Parser,
                         self).reduce_is_invalid(rule, ast,
                                                 tokens, first, last)
+
         if invalid:
             return invalid
+
         if rule == ('and', ('expr', 'jmp_false', 'expr', '\\e_come_from_opt')):
             # Test that jmp_false jumps to the end of "and"
             # or that it jumps to the same place as the end of "and"
@@ -249,6 +258,16 @@ def reduce_is_invalid(self, rule, ast, tokens, first, last):
             jmp_target = jmp_true.offset + jmp_true.attr + 3
             return not (jmp_target == tokens[last].offset or
                         tokens[last].pattr == jmp_true.pattr)
+
+        elif (rule[0] == 'whilestmt' and
+              rule[1][0:-2] ==
+                      ('SETUP_LOOP', 'testexpr', 'l_stmts_opt',
+                       'JUMP_BACK', 'JUMP_BACK')):
+            # Make sure that the jump backs all go to the same place
+            i = last-1
+            while (tokens[i] != 'JUMP_BACK'):
+                i -= 1
+            return tokens[i].attr != tokens[i-1].attr
         # elif rule[0] == ('conditional_true'):
         #     # FIXME: the below is a hack: we check expr for
         #     # nodes that could have possibly been a been a Boolean.
