Updated error messages & moved NaN to utility code

Cython/Compiler/ModuleNode.py

@@ -499,19 +499,8 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
   #define DL_EXPORT(t) t
 #endif
 
-#ifdef PY_LONG_LONG
-    #define %(LONG_LONG_MAX)s PY_LLONG_MAX
-    #define %(ULONG_LONG_MAX)s PY_ULLONG_MAX
-#else
-    #define PY_LONG_LONG LONG_LONG
-
-    #if defined(LLONG_MAX)
-        #define %(LONG_LONG_MAX)s LLONG_MAX
-        #define %(ULONG_LONG_MAX)s ULLONG_MAX
-    #else
-        #define %(LONG_LONG_MAX)s LONG_MAX
-        #define %(ULONG_LONG_MAX)s ULONG_MAX
-    #endif
+#ifndef PY_LONG_LONG
+  #define PY_LONG_LONG LONG_LONG
 #endif
 
 #if PY_VERSION_HEX < 0x02040000
@@ -648,7 +637,7 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
   #define __Pyx_PyInt_AsHash_t   PyInt_AsSsize_t
 #endif
 
-""" % vars(Naming))
+""")
 
         code.put("""
 #if PY_MAJOR_VERSION >= 3
@@ -714,47 +703,7 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
         code.putln("#if defined(WIN32) || defined(MS_WINDOWS)")
         code.putln("#define _USE_MATH_DEFINES")
         code.putln("#endif")
-
-        code.putln("""
-/* Define NAN */
-#ifdef Py_NAN
-    #include <math.h>
-    #define %(pyx_nan)s Py_NAN
-#else
-    #if defined(__GNUC__)
-        #define _GNU_SOURCE
-    #endif
-
-    #include <math.h>
-
-    #ifdef NAN
-        #define %(pyx_nan)s NAN
-    #else
-        #if defined(HUGE_VALL)
-            #define %(pyx_nan)s HUGE_VALL
-        #elif defined(__STDC__) && __STDC_VERSION__ >= 199901L
-            /* C99 or greater */
-            #include <float.h>
-            #define %(pyx_nan)s LDBL_MAX
-        #else
-            static PY_LONG_LONG __pyx__nan = PY_LLONG_MAX;
-            #define %(pyx_nan)s (*(double*) &__pyx__nan)
-        #endif
-    #endif
-#endif
-
-#ifdef PY_LONG_LONG
-    #define __PYX_LONG_LONG_MAX PY_LLONG_MAX
-    #define __PYX_ULONG_LONG_MAX PY_ULLONG_MAX
-#elif defined(LLONG_MAX)
-    #define __PYX_LONG_LONG_MAX LLONG_MAX
-    #define __PYX_ULONG_LONG_MAX ULLONG_MAX
-#else
-    /* This should probably suffice, even if not strictly the largest value */
-    #define __PYX_LONG_LONG_MAX LONG_MAX
-    #define __PYX_ULONG_LONG_MAX ULONG_MAX
-#endif
-""" % {'pyx_nan': Naming.NAN})
+        code.putln("#include <math.h>")
 
         code.putln("#define %s" % Naming.h_guard_prefix + self.api_name(env))
         code.putln("#define %s" % Naming.api_guard_prefix + self.api_name(env))

Cython/Compiler/Naming.py

@@ -116,7 +116,7 @@ h_guard_prefix   = "__PYX_HAVE__"
 api_guard_prefix = "__PYX_HAVE_API__"
 api_func_guard   = "__PYX_HAVE_API_FUNC_"
 
-NAN              = "__PYX_NAN"
+PYX_NAN          = "__PYX_NAN"
 HUGE_VAL         = "Py_HUGE_VAL"
 LONG_LONG_MAX    = "__PYX_LONG_LONG_MAX"
 ULONG_LONG_MAX   = "__PYX_ULONG_LONG_MAX"

Cython/Compiler/Nodes.py

@@ -5891,7 +5891,7 @@ class ParallelStatNode(StatNode, ParallelNode):
     def analyse_expressions(self, env):
         self.body.analyse_expressions(env)
         self.analyse_sharing_attributes(env)
-        self.check_use_unitialized_privates()
+        self.check_independent_iterations()
 
     def analyse_sharing_attributes(self, env):
         """
@@ -5997,9 +5997,9 @@ class ParallelStatNode(StatNode, ParallelNode):
         code.putln("%s = %s;" % (cname, entry.cname))
         entry.cname = cname
 
-    def check_use_unitialized_privates(self):
+    def check_independent_iterations(self):
         """
-        This checks for uninitialized private variables, it's far from
+        This checks for uninitialized thread-private variables, it's far from
         fool-proof as it does not take control flow into account, nor
         assignment to a variable as both the lhs and rhs. So it detects only
         cases like this:
@@ -6009,7 +6009,8 @@ class ParallelStatNode(StatNode, ParallelNode):
                 x = i
 
         Fortunately, it doesn't need to be perfect, as we still initialize
-        private variables to maximum values, NULL or NaN whenever possible.
+        private variables to "invalid" values, such as NULL or NaN whenever
+        possible.
         """
         from Cython.Compiler import ParseTreeTransforms
 
@@ -6023,18 +6024,25 @@ class ParallelStatNode(StatNode, ParallelNode):
                 # Reading reduction variables is valid (in fact necessary)
                 # before assignment
                 if not op and pos < assignment_pos:
-                    error(pos, "Private variable referenced before assignment")
+                    if self.is_prange:
+                        error(pos, "Expression value depends on previous loop "
+                                   "iteration, cannot execute in parallel")
+                    else:
+                        error(pos, "Expression depends on an uninitialized "
+                                   "thread-private variable")
 
     def initialize_privates_to_nan(self, code, exclude=None):
         code.putln("/* Initialize private variables to invalid values */")
 
         for entry, op in self.privates.iteritems():
             if not op and (not exclude or entry != exclude):
-                max_value = entry.type.max_value()
+                invalid_value = entry.type.invalid_value()
 
-                if max_value:
+                if invalid_value:
+                    code.globalstate.use_utility_code(
+                                invalid_values_utility_code)
                     code.putln("%s = %s;" % (entry.cname,
-                                             entry.type.cast_code(max_value)))
+                                             entry.type.cast_code(invalid_value)))
 
     def declare_closure_privates(self, code):
         """
@@ -7553,3 +7561,39 @@ bad:
     'EMPTY_BYTES' : Naming.empty_bytes,
     "MODULE": Naming.module_cname,
 })
+
+################ Utility code for cython.parallel stuff ################
+
+invalid_values_utility_code = UtilityCode(proto="""
+#ifdef HAVE_LONG_LONG
+    #define %(LONG_LONG_MAX)s PY_LLONG_MAX
+    #define %(ULONG_LONG_MAX)s PY_ULLONG_MAX
+#else
+    #define PY_LONG_LONG LONG_LONG
+
+    #if defined(LLONG_MAX)
+        #define %(LONG_LONG_MAX)s LLONG_MAX
+        #define %(ULONG_LONG_MAX)s ULLONG_MAX
+    #else
+        #define %(LONG_LONG_MAX)s LONG_MAX
+        #define %(ULONG_LONG_MAX)s ULONG_MAX
+    #endif
+#endif
+
+/* Define NAN */
+#ifdef Py_NAN
+    #define %(PYX_NAN)s Py_NAN
+#elif defined(NAN)
+    #define %(PYX_NAN)s NAN
+#elif defined(HUGE_VALL)
+    #define %(PYX_NAN)s HUGE_VALL
+#elif defined(__STDC__) && __STDC_VERSION__ >= 199901L
+    /* C99 or greater */
+    #include <float.h>
+    #define %(PYX_NAN)s LDBL_MAX
+#else
+    static PY_LONG_LONG __pyx__nan = %(LONG_LONG_MAX)s;
+    #define %(PYX_NAN)s (*(double*) &__pyx__nan)
+#endif
+"""  % vars(Naming))
+

Cython/Compiler/PyrexTypes.py

@@ -27,10 +27,10 @@ class BaseType(object):
         else:
             return base_code
 
-    def max_value(self):
+    def invalid_value(self):
         """
-        Returns the maximum or most invalid value an object of this type can
-        assume as a C expression string. Returns None if no such value exists.
+        Returns the most invalid value an object of this type can assume as a
+        C expression string. Returns None if no such value exists.
         """
 
 class PyrexType(BaseType):
@@ -384,8 +384,8 @@ class PyObjectType(PyrexType):
         else:
             return cname
 
-    def max_value(self):
-        return "NULL"
+    def invalid_value(self):
+        return "1"
 
 
 class BuiltinObjectType(PyObjectType):
@@ -912,7 +912,7 @@ class CIntType(CNumericType):
     def assignable_from_resolved_type(self, src_type):
         return src_type.is_int or src_type.is_enum or src_type is error_type
 
-    def max_value(self):
+    def invalid_value(self):
         return typename_to_maxval[rank_to_type_name[self.rank]][not self.signed]
 
 class CAnonEnumType(CIntType):
@@ -1121,8 +1121,8 @@ class CFloatType(CNumericType):
     def assignable_from_resolved_type(self, src_type):
         return (src_type.is_numeric and not src_type.is_complex) or src_type is error_type
 
-    def max_value(self):
-        return Naming.NAN
+    def invalid_value(self):
+        return Naming.PYX_NAN
 
 class CComplexType(CNumericType):
 
@@ -1636,8 +1636,8 @@ class CPtrType(CType):
         else:
             return CPtrType(base_type)
 
-    def max_value(self):
-        return "NULL"
+    def invalid_value(self):
+        return "1"
 
 class CNullPtrType(CPtrType):
 
@@ -2375,7 +2375,7 @@ typename_to_maxval = {
     "int"  : ("INT_MAX", "UINT_MAX"),
     "long" : ("LONG_MAX", "ULONG_MAX"),
     "PY_LONG_LONG" : (Naming.LONG_LONG_MAX, Naming.ULONG_LONG_MAX),
-    # CFloatType overrides max_value
+    # CFloatType overrides invalid_value
 }
 
 RANK_INT  = list(rank_to_type_name).index('int')

tests/errors/e_cython_parallel.pyx

@@ -73,7 +73,7 @@ e_cython_parallel.pyx:30:9: Can only iterate over an iteration variable
 e_cython_parallel.pyx:33:10: Must be of numeric type, not int *
 e_cython_parallel.pyx:36:33: Closely nested 'with parallel:' blocks are disallowed
 e_cython_parallel.pyx:39:12: The parallel directive must be called
-e_cython_parallel.pyx:45:10: Private variable referenced before assignment
-e_cython_parallel.pyx:55:9: Private variable referenced before assignment
+e_cython_parallel.pyx:45:10: Expression value depends on previous loop iteration, cannot execute in parallel
+e_cython_parallel.pyx:55:9: Expression depends on an uninitialized thread-private variable
 e_cython_parallel.pyx:60:6: Reduction operator '*' is inconsistent with previous reduction operator '+'
 """

tests/run/sequential_parallel.pyx

@@ -214,7 +214,7 @@ def test_nan_init():
             d1 == 10 or d2 == 10 or
             e1 == 10 or e2 == 10 or
             f == 10.0 or g == 10.0 or h == 10.0 or
-            p != NULL):
+            p == <void *> 10):
 
             errp[0] = 1