Support Python 3.8.

MatthieuDartiailh · Oct 16, 2018 · 674cb26 · 674cb26
1 parent a49c874
commit 674cb26
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Showing 3 changed files with 60 additions and 55 deletions.
diff --git a/bytecode/instr.py b/bytecode/instr.py
@@ -145,31 +145,32 @@ def _check_arg_int(name, arg):
                          % name)
 
 
-_stack_effects = {
-    # NOTE: the entries are all 2-tuples.  Entry[0/False] is non-taken jumps.
-    # Entry[1/True] is for taken jumps.
-
-    # opcodes not in dis.stack_effect
-    _opcode.opmap['EXTENDED_ARG']: (0, 0),
-    _opcode.opmap['NOP']: (0, 0),
-
-    # Jump taken/not-taken are different:
-    _opcode.opmap['JUMP_IF_TRUE_OR_POP']: (-1, 0),
-    _opcode.opmap['JUMP_IF_FALSE_OR_POP']: (-1, 0),
-    _opcode.opmap['FOR_ITER']: (1, -1),
-    _opcode.opmap['SETUP_WITH']: (1, 6),
-    _opcode.opmap['SETUP_ASYNC_WITH']: (0, 5),
-    _opcode.opmap['SETUP_EXCEPT']: (0, 6),   # as of 3.7, below for <=3.6
-    _opcode.opmap['SETUP_FINALLY']: (0, 6),  # as of 3.7, below for <=3.6
-}
-
-# More stack effect values that are unique to the version of Python.
-if sys.version_info < (3, 7):
-    _stack_effects.update({
-        _opcode.opmap['SETUP_WITH']: (7, 7),
-        _opcode.opmap['SETUP_EXCEPT']: (6, 9),
-        _opcode.opmap['SETUP_FINALLY']: (6, 9),
-    })
+if sys.version_info < (3, 8):
+    _stack_effects = {
+        # NOTE: the entries are all 2-tuples.  Entry[0/False] is non-taken jumps.
+        # Entry[1/True] is for taken jumps.
+
+        # opcodes not in dis.stack_effect
+        _opcode.opmap['EXTENDED_ARG']: (0, 0),
+        _opcode.opmap['NOP']: (0, 0),
+
+        # Jump taken/not-taken are different:
+        _opcode.opmap['JUMP_IF_TRUE_OR_POP']: (-1, 0),
+        _opcode.opmap['JUMP_IF_FALSE_OR_POP']: (-1, 0),
+        _opcode.opmap['FOR_ITER']: (1, -1),
+        _opcode.opmap['SETUP_WITH']: (1, 6),
+        _opcode.opmap['SETUP_ASYNC_WITH']: (0, 5),
+        _opcode.opmap['SETUP_EXCEPT']: (0, 6),   # as of 3.7, below for <=3.6
+        _opcode.opmap['SETUP_FINALLY']: (0, 6),  # as of 3.7, below for <=3.6
+    }
+
+    # More stack effect values that are unique to the version of Python.
+    if sys.version_info < (3, 7):
+        _stack_effects.update({
+            _opcode.opmap['SETUP_WITH']: (7, 7),
+            _opcode.opmap['SETUP_EXCEPT']: (6, 9),
+            _opcode.opmap['SETUP_FINALLY']: (6, 9),
+        })
 
 
 class Instr:
@@ -298,19 +299,18 @@ def lineno(self, lineno):
         self._set(self._name, self._arg, lineno)
 
     def stack_effect(self, jump=None):
-        effect = _stack_effects.get(self._opcode, None)
-        if effect is not None:
-            return max(effect) if jump is None else effect[jump]
-
-        # TODO: if dis.stack_effect ever expands to take the 'jump' parameter
-        # then we should pass that through, and perhaps remove some of the
-        # overrides that are set up in _init_stack_effects()
-
         # All opcodes whose arguments are not represented by integers have
         # a stack_effect indepent of their argument.
         arg = (self._arg if isinstance(self._arg, int) else
-               0 if self._opcode >= _opcode.HAVE_ARGUMENT else None)
-        return dis.stack_effect(self._opcode, arg)
+            0 if self._opcode >= _opcode.HAVE_ARGUMENT else None)
+
+        if sys.version_info < (3, 8):
+            effect = _stack_effects.get(self._opcode, None)
+            if effect is not None:
+                return max(effect) if jump is None else effect[jump]
+            return dis.stack_effect(self._opcode, arg)
+        else:
+            return dis.stack_effect(self._opcode, arg, jump=jump)
 
     def copy(self):
         return self.__class__(self._name, self._arg, lineno=self._lineno)

diff --git a/bytecode/tests/test_cfg.py b/bytecode/tests/test_cfg.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 import io
+import sys
 import unittest
 import contextlib
 from bytecode import (Label, Compare, SetLineno, Instr,
@@ -215,6 +216,7 @@ def test_from_bytecode(self):
                                 Instr('RETURN_VALUE', lineno=4)])
         # FIXME: test other attributes
 
+    @unittest.skipIf(sys.version_info >= (3, 8), "requires Python < 3.8")
     def test_from_bytecode_loop(self):
         # for x in (1, 2, 3):
         #     if x == 2:

diff --git a/bytecode/tests/test_peephole_opt.py b/bytecode/tests/test_peephole_opt.py
@@ -1,3 +1,4 @@
+import sys
 import unittest
 from bytecode import Label, Instr, Compare, Bytecode, ControlFlowGraph
 from bytecode import peephole_opt
@@ -432,27 +433,28 @@ def test_return_value(self):
         # return + JUMP_ABSOLUTE: remove JUMP_ABSOLUTE
         # while 1:
         #     return 7
-        setup_loop = Label()
-        return_label = Label()
-        code = Bytecode([setup_loop,
-                         Instr('SETUP_LOOP', return_label, lineno=2),
-                         Instr('LOAD_CONST', 7, lineno=3),
-                         Instr('RETURN_VALUE', lineno=3),
-                         Instr('JUMP_ABSOLUTE', setup_loop, lineno=3),
-                         Instr('POP_BLOCK', lineno=3),
-                         return_label,
-                         Instr('LOAD_CONST', None, lineno=3),
-                         Instr('RETURN_VALUE', lineno=3)])
-        code = ControlFlowGraph.from_bytecode(code)
+        if sys.version_info < (3, 8):
+            setup_loop = Label()
+            return_label = Label()
+            code = Bytecode([setup_loop,
+                             Instr('SETUP_LOOP', return_label, lineno=2),
+                             Instr('LOAD_CONST', 7, lineno=3),
+                             Instr('RETURN_VALUE', lineno=3),
+                             Instr('JUMP_ABSOLUTE', setup_loop, lineno=3),
+                             Instr('POP_BLOCK', lineno=3),
+                             return_label,
+                             Instr('LOAD_CONST', None, lineno=3),
+                             Instr('RETURN_VALUE', lineno=3)])
+            code = ControlFlowGraph.from_bytecode(code)
 
-        end_loop = Label()
-        self.check(code,
-                   Instr('SETUP_LOOP', end_loop, lineno=2),
-                   Instr('LOAD_CONST', 7, lineno=3),
-                   Instr('RETURN_VALUE', lineno=3),
-                   end_loop,
-                   Instr('LOAD_CONST', None, lineno=3),
-                   Instr('RETURN_VALUE', lineno=3))
+            end_loop = Label()
+            self.check(code,
+                       Instr('SETUP_LOOP', end_loop, lineno=2),
+                       Instr('LOAD_CONST', 7, lineno=3),
+                       Instr('RETURN_VALUE', lineno=3),
+                       end_loop,
+                       Instr('LOAD_CONST', None, lineno=3),
+                       Instr('RETURN_VALUE', lineno=3))
 
     def test_not_jump_if_false(self):
         # Replace UNARY_NOT+POP_JUMP_IF_FALSE with POP_JUMP_IF_TRUE
@@ -630,6 +632,7 @@ def test_jump_if_true_to_jump_if_false(self):
                    Instr('LOAD_CONST', None),
                    Instr('RETURN_VALUE'))
 
+    @unittest.skipIf(sys.version_info >= (3, 8), "requires Python < 3.8")
     def test_jump_if_false_to_jump_if_false(self):
         # Replace JUMP_IF_FALSE_OR_POP jumping to POP_JUMP_IF_FALSE <label>
         # with POP_JUMP_IF_FALSE <label>