Support for "volatile" keyword

Cython/Compiler/Code.py

@@ -822,8 +822,8 @@ class FunctionState(object):
 
         A C string referring to the variable is returned.
         """
-        if type.is_const and not type.is_reference:
-            type = type.const_base_type
+        if type.is_cv_qualified and not type.is_reference:
+            type = type.cv_base_type
         elif type.is_reference and not type.is_fake_reference:
             type = type.ref_base_type
         if not type.is_pyobject and not type.is_memoryviewslice:

Cython/Compiler/ExprNodes.py

@@ -881,8 +881,8 @@ class ExprNode(Node):
         if used_as_reference and not src_type.is_reference:
             dst_type = dst_type.ref_base_type
 
-        if src_type.is_const:
-            src_type = src_type.const_base_type
+        if src_type.is_cv_qualified:
+            src_type = src_type.cv_base_type
 
         if src_type.is_fused or dst_type.is_fused:
             # See if we are coercing a fused function to a pointer to a
@@ -2868,8 +2868,8 @@ class NextNode(AtomicExprNode):
             item_type = env.lookup_operator_for_types(self.pos, "*", [iterator_type]).type.return_type
             if item_type.is_reference:
                 item_type = item_type.ref_base_type
-            if item_type.is_const:
-                item_type = item_type.const_base_type
+            if item_type.is_cv_qualified:
+                item_type = item_type.cv_base_type
             return item_type
         else:
             # Avoid duplication of complicated logic.

Cython/Compiler/MemoryView.py

@@ -487,7 +487,7 @@ def copy_c_or_fortran_cname(memview):
 
 def get_copy_new_utility(pos, from_memview, to_memview):
     if (from_memview.dtype != to_memview.dtype and
-            not (from_memview.dtype.is_const and from_memview.dtype.const_base_type == to_memview.dtype)):
+            not (from_memview.dtype.is_cv_qualified and from_memview.dtype.cv_base_type == to_memview.dtype)):
         error(pos, "dtypes must be the same!")
         return
     if len(from_memview.axes) != len(to_memview.axes):

Cython/Compiler/Nodes.py

@@ -1273,8 +1273,10 @@ class FusedTypeNode(CBaseTypeNode):
         return PyrexTypes.FusedType(types, name=self.name)
 
 
-class CConstTypeNode(CBaseTypeNode):
+class CConstOrVolatileTypeNode(CBaseTypeNode):
     # base_type     CBaseTypeNode
+    # is_const      boolean
+    # is_volatile   boolean
 
     child_attrs = ["base_type"]
 
@@ -1282,8 +1284,8 @@ class CConstTypeNode(CBaseTypeNode):
         base = self.base_type.analyse(env, could_be_name)
         if base.is_pyobject:
             error(self.pos,
-                  "Const base type cannot be a Python object")
-        return PyrexTypes.c_const_type(base)
+                  "Const/volatile base type cannot be a Python object")
+        return PyrexTypes.c_const_or_volatile_type(base, self.is_const, self.is_volatile)
 
 
 class CVarDefNode(StatNode):

Cython/Compiler/Parsing.py

@@ -317,8 +317,8 @@ def p_typecast(s):
     base_type = p_c_base_type(s)
     is_memslice = isinstance(base_type, Nodes.MemoryViewSliceTypeNode)
     is_template = isinstance(base_type, Nodes.TemplatedTypeNode)
-    is_const = isinstance(base_type, Nodes.CConstTypeNode)
-    if (not is_memslice and not is_template and not is_const
+    is_const_volatile = isinstance(base_type, Nodes.CConstOrVolatileTypeNode)
+    if (not is_memslice and not is_template and not is_const_volatile
         and base_type.name is None):
         s.error("Unknown type")
     declarator = p_c_declarator(s, empty = 1)
@@ -2479,16 +2479,31 @@ def p_c_simple_base_type(s, self_flag, nonempty, templates = None):
     complex = 0
     module_path = []
     pos = s.position()
-    if not s.sy == 'IDENT':
-        error(pos, "Expected an identifier, found '%s'" % s.sy)
-    if s.systring == 'const':
+
+    # Handle const/volatile
+    is_const = is_volatile = 0
+    while True:
+        if s.systring == 'const':
+            if is_const: error(pos, "Duplicate 'const'")
+            is_const = 1
+        elif s.systring == 'volatile':
+            if is_volatile: error(pos, "Duplicate 'volatile'")
+            is_volatile = 1
+        else:
+            break
         s.next()
+    if is_const or is_volatile:
         base_type = p_c_base_type(s, self_flag=self_flag, nonempty=nonempty, templates=templates)
         if isinstance(base_type, Nodes.MemoryViewSliceTypeNode):
             # reverse order to avoid having to write "(const int)[:]"
-            base_type.base_type_node = Nodes.CConstTypeNode(pos, base_type=base_type.base_type_node)
+            base_type.base_type_node = Nodes.CConstOrVolatileTypeNode(pos,
+                base_type=base_type.base_type_node, is_const=is_const, is_volatile=is_volatile)
             return base_type
-        return Nodes.CConstTypeNode(pos, base_type=base_type)
+        return Nodes.CConstOrVolatileTypeNode(pos,
+            base_type=base_type, is_const=is_const, is_volatile=is_volatile)
+
+    if s.sy != 'IDENT':
+        error(pos, "Expected an identifier, found '%s'" % s.sy)
     if looking_at_base_type(s):
         #print "p_c_simple_base_type: looking_at_base_type at", s.position()
         is_basic = 1

Cython/Compiler/PyrexTypes.py

@@ -176,7 +176,9 @@ class PyrexType(BaseType):
     #  is_ptr                boolean     Is a C pointer type
     #  is_null_ptr           boolean     Is the type of NULL
     #  is_reference          boolean     Is a C reference type
-    #  is_const              boolean     Is a C const type.
+    #  is_const              boolean     Is a C const type
+    #  is_volatile           boolean     Is a C volatile type
+    #  is_cv_qualified       boolean     Is a C const or volatile type
     #  is_cfunction          boolean     Is a C function type
     #  is_struct_or_union    boolean     Is a C struct or union type
     #  is_struct             boolean     Is a C struct type
@@ -236,6 +238,8 @@ class PyrexType(BaseType):
     is_null_ptr = 0
     is_reference = 0
     is_const = 0
+    is_volatile = 0
+    is_cv_qualified = 0
     is_cfunction = 0
     is_struct_or_union = 0
     is_cpp_class = 0
@@ -713,8 +717,8 @@ class MemoryViewSliceType(PyrexType):
             to_axes_f = contig_dim + follow_dim * (ndim -1)
 
             dtype = self.dtype
-            if dtype.is_const:
-                dtype = dtype.const_base_type
+            if dtype.is_cv_qualified:
+                dtype = dtype.cv_base_type
 
             to_memview_c = MemoryViewSliceType(dtype, to_axes_c)
             to_memview_f = MemoryViewSliceType(dtype, to_axes_f)
@@ -791,15 +795,18 @@ class MemoryViewSliceType(PyrexType):
         #    return False
 
         src_dtype, dst_dtype = src.dtype, dst.dtype
-        if dst_dtype.is_const:
-            # Requesting read-only views is always ok => consider only the non-const base type.
-            dst_dtype = dst_dtype.const_base_type
-            if src_dtype.is_const:
-                # When assigning between read-only views, compare only the non-const base types.
-                src_dtype = src_dtype.const_base_type
-        elif copying and src_dtype.is_const:
-            # Copying by value => ignore const on source.
-            src_dtype = src_dtype.const_base_type
+        # We can add but not remove const/volatile modifiers
+        # (except if we are copying by value, then anything is fine)
+        if not copying:
+            if src_dtype.is_const and not dst_dtype.is_const:
+                return False
+            if src_dtype.is_volatile and not dst_dtype.is_volatile:
+                return False
+        # const/volatile checks are done, remove those qualifiers
+        if src_dtype.is_cv_qualified:
+            src_dtype = src_dtype.cv_base_type
+        if dst_dtype.is_cv_qualified:
+            dst_dtype = dst_dtype.cv_base_type
 
         if src_dtype != dst_dtype:
             return False
@@ -1558,58 +1565,74 @@ class PythranExpr(CType):
         return hash(self.pythran_type)
 
 
-class CConstType(BaseType):
+class CConstOrVolatileType(BaseType):
+    "A C const or volatile type"
 
-    is_const = 1
+    is_cv_qualified = 1
 
-    def __init__(self, const_base_type):
-        self.const_base_type = const_base_type
-        if const_base_type.has_attributes and const_base_type.scope is not None:
-            from . import Symtab
-            self.scope = Symtab.CConstScope(const_base_type.scope)
+    def __init__(self, base_type, is_const=0, is_volatile=0):
+        self.cv_base_type = base_type
+        self.is_const = is_const
+        self.is_volatile = is_volatile
+        if base_type.has_attributes and base_type.scope is not None:
+            from .Symtab import CConstOrVolatileScope
+            self.scope = CConstOrVolatileScope(base_type.scope, is_const, is_volatile)
+
+    def cv_string(self):
+        cvstring = ""
+        if self.is_const:
+            cvstring = "const " + cvstring
+        if self.is_volatile:
+            cvstring = "volatile " + cvstring
+        return cvstring
 
     def __repr__(self):
-        return "<CConstType %s>" % repr(self.const_base_type)
+        return "<CConstOrVolatileType %s%r>" % (self.cv_string(), self.cv_base_type)
 
     def __str__(self):
         return self.declaration_code("", for_display=1)
 
     def declaration_code(self, entity_code,
             for_display = 0, dll_linkage = None, pyrex = 0):
+        cv = self.cv_string()
         if for_display or pyrex:
-            return "const " + self.const_base_type.declaration_code(entity_code, for_display, dll_linkage, pyrex)
+            return cv + self.cv_base_type.declaration_code(entity_code, for_display, dll_linkage, pyrex)
         else:
-            return self.const_base_type.declaration_code("const %s" % entity_code, for_display, dll_linkage, pyrex)
+            return self.cv_base_type.declaration_code(cv + entity_code, for_display, dll_linkage, pyrex)
 
     def specialize(self, values):
-        base_type = self.const_base_type.specialize(values)
-        if base_type == self.const_base_type:
+        base_type = self.cv_base_type.specialize(values)
+        if base_type == self.cv_base_type:
             return self
-        else:
-            return CConstType(base_type)
+        return CConstOrVolatileType(base_type,
+                self.is_const, self.is_volatile)
 
     def deduce_template_params(self, actual):
-        return self.const_base_type.deduce_template_params(actual)
+        return self.cv_base_type.deduce_template_params(actual)
 
     def can_coerce_to_pyobject(self, env):
-        return self.const_base_type.can_coerce_to_pyobject(env)
+        return self.cv_base_type.can_coerce_to_pyobject(env)
 
     def can_coerce_from_pyobject(self, env):
-        return self.const_base_type.can_coerce_from_pyobject(env)
+        return self.cv_base_type.can_coerce_from_pyobject(env)
 
     def create_to_py_utility_code(self, env):
-        if self.const_base_type.create_to_py_utility_code(env):
-            self.to_py_function = self.const_base_type.to_py_function
+        if self.cv_base_type.create_to_py_utility_code(env):
+            self.to_py_function = self.cv_base_type.to_py_function
             return True
 
     def same_as_resolved_type(self, other_type):
-        if other_type.is_const:
-            return self.const_base_type.same_as_resolved_type(other_type.const_base_type)
-        # Accept const LHS <- non-const RHS.
-        return self.const_base_type.same_as_resolved_type(other_type)
+        if other_type.is_cv_qualified:
+            return self.cv_base_type.same_as_resolved_type(other_type.cv_base_type)
+        # Accept cv LHS <- non-cv RHS.
+        return self.cv_base_type.same_as_resolved_type(other_type)
 
     def __getattr__(self, name):
-        return getattr(self.const_base_type, name)
+        return getattr(self.cv_base_type, name)
+
+
+def CConstType(base_type):
+    return CConstOrVolatileType(base_type, is_const=1)
 
 
 class FusedType(CType):
@@ -2302,8 +2325,8 @@ class CPointerBaseType(CType):
 
     def __init__(self, base_type):
         self.base_type = base_type
-        if base_type.is_const:
-            base_type = base_type.const_base_type
+        if base_type.is_cv_qualified:
+            base_type = base_type.cv_base_type
         for char_type in (c_char_type, c_uchar_type, c_schar_type):
             if base_type.same_as(char_type):
                 self.is_string = 1
@@ -2527,8 +2550,8 @@ class CPtrType(CPointerBaseType):
             return 1
         if other_type.is_null_ptr:
             return 1
-        if self.base_type.is_const:
-            self = CPtrType(self.base_type.const_base_type)
+        if self.base_type.is_cv_qualified:
+            self = CPtrType(self.base_type.cv_base_type)
         if self.base_type.is_cfunction:
             if other_type.is_ptr:
                 other_type = other_type.base_type.resolve()
@@ -3709,8 +3732,8 @@ class CppClassType(CType):
         return specialized
 
     def deduce_template_params(self, actual):
-        if actual.is_const:
-            actual = actual.const_base_type
+        if actual.is_cv_qualified:
+            actual = actual.cv_base_type
         if actual.is_reference:
             actual = actual.ref_base_type
         if self == actual:
@@ -4452,10 +4475,10 @@ def widest_numeric_type(type1, type2):
         type1 = type1.ref_base_type
     if type2.is_reference:
         type2 = type2.ref_base_type
-    if type1.is_const:
-        type1 = type1.const_base_type
-    if type2.is_const:
-        type2 = type2.const_base_type
+    if type1.is_cv_qualified:
+        type1 = type1.cv_base_type
+    if type2.is_cv_qualified:
+        type2 = type2.cv_base_type
     if type1 == type2:
         widest_type = type1
     elif type1.is_complex or type2.is_complex:
@@ -4675,6 +4698,13 @@ def c_const_type(base_type):
     else:
         return CConstType(base_type)
 
+def c_const_or_volatile_type(base_type, is_const, is_volatile):
+    # Construct a C const/volatile type.
+    if base_type is error_type:
+        return error_type
+    else:
+        return CConstOrVolatileType(base_type, is_const, is_volatile)
+
 def same_type(type1, type2):
     return type1.same_as(type2)
 

Cython/Compiler/Symtab.py

@@ -2523,23 +2523,27 @@ class PropertyScope(Scope):
             return None
 
 
-class CConstScope(Scope):
+class CConstOrVolatileScope(Scope):
 
-    def __init__(self, const_base_type_scope):
+    def __init__(self, base_type_scope, is_const=0, is_volatile=0):
         Scope.__init__(
             self,
-            'const_' + const_base_type_scope.name,
-            const_base_type_scope.outer_scope,
-            const_base_type_scope.parent_scope)
-        self.const_base_type_scope = const_base_type_scope
+            'cv_' + base_type_scope.name,
+            base_type_scope.outer_scope,
+            base_type_scope.parent_scope)
+        self.base_type_scope = base_type_scope
+        self.is_const = is_const
+        self.is_volatile = is_volatile
 
     def lookup_here(self, name):
-        entry = self.const_base_type_scope.lookup_here(name)
+        entry = self.base_type_scope.lookup_here(name)
         if entry is not None:
             entry = copy.copy(entry)
-            entry.type = PyrexTypes.c_const_type(entry.type)
+            entry.type = PyrexTypes.c_const_or_volatile_type(
+                    entry.type, self.is_const, self.is_volatile)
             return entry
 
+
 class TemplateScope(Scope):
     def __init__(self, name, outer_scope):
         Scope.__init__(self, name, outer_scope, None)

Cython/Compiler/TypeInference.py

@@ -533,8 +533,8 @@ def find_spanning_type(type1, type2):
 def simply_type(result_type, pos):
     if result_type.is_reference:
         result_type = result_type.ref_base_type
-    if result_type.is_const:
-        result_type = result_type.const_base_type
+    if result_type.is_cv_qualified:
+        result_type = result_type.cv_base_type
     if result_type.is_cpp_class:
         result_type.check_nullary_constructor(pos)
     if result_type.is_array:

tests/compile/volatile.pyx

+# mode: compile
+
+cdef volatile int x = 1
+
+cdef const volatile char* greeting1 = "hello world"
+cdef volatile const char* greeting2 = "goodbye"
+
+
+cdef extern from "stdlib.h":
+    volatile void* malloc(size_t)
+
+cdef volatile long* test(volatile size_t s):
+    cdef volatile long* arr = <long*><volatile long*>malloc(s)
+    return arr
+
+
+test(64)

tests/errors/const_decl_errors.pyx

@@ -19,9 +19,11 @@ cdef func(const int a, const int* b, const (int*) c, const S s, int *const d,
     d = NULL
     t = &s
 
+cdef volatile object v
+
 
 _ERRORS = """
-3:5: Const base type cannot be a Python object
+3:5: Const/volatile base type cannot be a Python object
 8:5: Assignment to const 'x'
 15:4: Assignment to const 'a'
 16:4: Assignment to const 'c'
@@ -29,4 +31,5 @@ _ERRORS = """
 18:5: Assignment to const attribute 'member'
 19:4: Assignment to const 'd'
 20:4: Assignment to const 't'
+22:5: Const/volatile base type cannot be a Python object
 """

tests/errors/duplicate_const.pyx

+# mode: error
+
+cdef extern from *:
+    cdef const const int a
+    cdef const volatile int b
+    cdef volatile const int c
+    cdef volatile volatile int d
+
+
+_ERRORS = """
+4:9: Duplicate 'const'
+7:9: Duplicate 'volatile'
+"""