Merge pull request #287 from gandalf013/switch_transform

add a directive to disable SwitchTransform

Cython/Compiler/Optimize.py

@@ -802,7 +802,7 @@ class IterationTransform(Visitor.EnvTransform):
             ])
 
 
-class SwitchTransform(Visitor.VisitorTransform):
+class SwitchTransform(Visitor.CythonTransform):
     """
     This transformation tries to turn long if statements into C switch statements.
     The requirement is that every clause be an (or of) var == value, where the var
@@ -917,6 +917,10 @@ class SwitchTransform(Visitor.VisitorTransform):
         return False
 
     def visit_IfStatNode(self, node):
+        if not self.current_directives.get('optimize.use_switch'):
+            self.visitchildren(node)
+            return node
+
         common_var = None
         cases = []
         for if_clause in node.if_clauses:
@@ -946,6 +950,10 @@ class SwitchTransform(Visitor.VisitorTransform):
         return switch_node
 
     def visit_CondExprNode(self, node):
+        if not self.current_directives.get('optimize.use_switch'):
+            self.visitchildren(node)
+            return node
+
         not_in, common_var, conditions = self.extract_common_conditions(
             None, node.test, True)
         if common_var is None \
@@ -958,6 +966,10 @@ class SwitchTransform(Visitor.VisitorTransform):
             node.true_val, node.false_val)
 
     def visit_BoolBinopNode(self, node):
+        if not self.current_directives.get('optimize.use_switch'):
+            self.visitchildren(node)
+            return node
+
         not_in, common_var, conditions = self.extract_common_conditions(
             None, node, True)
         if common_var is None \
@@ -972,6 +984,10 @@ class SwitchTransform(Visitor.VisitorTransform):
             ExprNodes.BoolNode(node.pos, value=False, constant_result=False))
 
     def visit_PrimaryCmpNode(self, node):
+        if not self.current_directives.get('optimize.use_switch'):
+            self.visitchildren(node)
+            return node
+
         not_in, common_var, conditions = self.extract_common_conditions(
             None, node, True)
         if common_var is None \
@@ -1015,6 +1031,10 @@ class SwitchTransform(Visitor.VisitorTransform):
         return replacement
 
     def visit_EvalWithTempExprNode(self, node):
+        if not self.current_directives.get('optimize.use_switch'):
+            self.visitchildren(node)
+            return node
+
         # drop unused expression temp from FlattenInListTransform
         orig_expr = node.subexpression
         temp_ref = node.lazy_temp

Cython/Compiler/Options.py

@@ -129,6 +129,7 @@ directive_defaults = {
 
 # optimizations
     'optimize.inline_defnode_calls': True,
+    'optimize.use_switch': True,
 
 # remove unreachable code
     'remove_unreachable': True,

Cython/Compiler/Pipeline.py

@@ -202,7 +202,7 @@ def create_pipeline(context, mode, exclude_classes=()):
         CalculateQualifiedNamesTransform(context),
         ConsolidateOverflowCheck(context),
         IterationTransform(context),
-        SwitchTransform(),
+        SwitchTransform(context),
         DropRefcountingTransform(),
         FinalOptimizePhase(context),
         GilCheck(),

runtests.py

@@ -693,10 +693,14 @@ class CythonCompileTestCase(unittest.TestCase):
                 if line.startswith("_ERRORS"):
                     out.close()
                     out = ErrorWriter()
+                elif line.startswith('_FAIL_C_COMPILE'):
+                    out.close()
+                    return '_FAIL_C_COMPILE'
                 else:
                     out.write(line)
         finally:
             source_and_output.close()
+
         try:
             geterrors = out.geterrors
         except AttributeError:
@@ -835,7 +839,14 @@ class CythonCompileTestCase(unittest.TestCase):
             finally:
                 sys.stderr = old_stderr
 
-        if errors or expected_errors:
+        if expected_errors == '_FAIL_C_COMPILE':
+            if errors:
+                print("\n=== Expected C compile error ===")
+                print("\n\n=== Got Cython errors: ===")
+                print('\n'.join(errors))
+                print('\n')
+                raise RuntimeError('should have generated extension code')
+        elif errors or expected_errors:
             try:
                 for expected, error in zip(expected_errors, errors):
                     self.assertEquals(expected, error)
@@ -854,10 +865,13 @@ class CythonCompileTestCase(unittest.TestCase):
                 raise
             return None
 
-        if self.cython_only:
         so_path = None
-        else:
+        if not self.cython_only:
+            try:
                 so_path = self.run_distutils(test_directory, module, workdir, incdir)
+            except:
+                if expected_errors != '_FAIL_C_COMPILE':
+                    raise
         return so_path
 
 class CythonRunTestCase(CythonCompileTestCase):
@@ -882,7 +896,7 @@ class CythonRunTestCase(CythonCompileTestCase):
                 self.success = False
                 ext_so_path = self.runCompileTest()
                 failures, errors = len(result.failures), len(result.errors)
-                if not self.cython_only:
+                if not self.cython_only and ext_so_path is not None:
                     self.run_tests(result, ext_so_path)
                 if failures == len(result.failures) and errors == len(result.errors):
                     # No new errors...

tests/errors/e_switch_transform.pyx

+# cython: optimize.use_switch=True
+# mode: error
+
+import cython
+
+cdef extern from "../run/includes/switch_transform_support.h":
+    enum:
+        ONE
+        ONE_AGAIN
+
+def is_not_one(int i):
+    return i != ONE and i != ONE_AGAIN
+
+_FAIL_C_COMPILE = True

tests/run/includes/switch_transform_support.h

+#ifndef SWITCH_TRANSFORM_SUPPORT_H_
+#define SWITCH_TRANSFORM_SUPPORT_H_ 1
+
+enum {
+    ONE=1,
+    ONE_AGAIN=1
+};
+
+#endif /* SWITCH_TRANSFORM_SUPPORT_H_ */

tests/run/switch_transform.pyx

+# cython: optimize.use_switch=False
+
+cdef extern from "includes/switch_transform_support.h":
+    enum:
+        ONE
+        ONE_AGAIN
+
+def is_not_one(int i):
+    """
+    >>> is_not_one(1)
+    False
+    >>> is_not_one(2)
+    True
+    """
+    return i != ONE and i != ONE_AGAIN