Introduce 'iso' qualifier and 'consume' keyword

Cython/Compiler/ExprNodes.py

@@ -1048,11 +1048,15 @@ class ExprNode(Node):
             src = CoerceToComplexNode(src, dst_type, env)
         else:
             # neither src nor dst are py types
+            # Qualified cypclass types can have nontrivial aliasing rules
+            # meaning type equality may not imply the coercion is valid.
+            if src_type.is_qualified_cyp_class and not dst_type.assignable_from(src_type):
+                self.fail_assignment(dst_type)
             # Added the string comparison, since for c types that
             # is enough, but Cython gets confused when the types are
             # in different pxi files.
             # TODO: Remove this hack and require shared declarations.
-            if not (src.type == dst_type or str(src.type) == str(dst_type) or dst_type.assignable_from(src_type)):
+            elif not (src.type == dst_type or str(src.type) == str(dst_type) or dst_type.assignable_from(src_type)):
                 self.fail_assignment(dst_type)
         return src
 
@@ -3945,8 +3949,8 @@ class IndexNode(_IndexingBaseNode):
         elif self.exception_check == '~':
             self.is_temp = True
         self.index = self.index.coerce_to(func_type.args[0].type, env)
-        self.type = func_type.return_type
-        if setting and not func_type.return_type.is_reference:
+        self.type = func_type.return_type.as_returned_type()
+        if setting and not self.type.is_reference:
             error(self.pos, "Can't set non-reference result '%s'" % self.type)
         return self
 
@@ -3979,7 +3983,7 @@ class IndexNode(_IndexingBaseNode):
             self.is_temp = True
 
         self.index = self.index.coerce_to(function.type.args[0].type, env)
-        self.type = func_type.return_type
+        self.type = func_type.return_type.as_returned_type()
         return self
 
     def analyse_cyp_class_setitem(self, env):
@@ -4019,7 +4023,7 @@ class IndexNode(_IndexingBaseNode):
             env.use_utility_code(UtilityCode.load_cached("CppExceptionConversion", "CppSupport.cpp"))
 
         self.index = self.index.coerce_to(function.type.args[0].type, env)
-        self.type = func_type.return_type
+        self.type = func_type.return_type.as_returned_type()
         return self
 
     def analyse_as_c_function(self, env):
@@ -6234,7 +6238,7 @@ class SimpleCallNode(CallNode):
             else:
                 self.type = PyrexTypes.CPtrType(self.function.class_type)
         else:
-            self.type = func_type.return_type
+            self.type = func_type.return_type.as_returned_type()
 
         if self.function.is_name or self.function.is_attribute:
             func_entry = self.function.entry
@@ -6723,7 +6727,7 @@ class PythonCapiCallNode(SimpleCallNode):
 
     def __init__(self, pos, function_name, func_type,
                  utility_code = None, py_name=None, **kwargs):
-        self.type = func_type.return_type
+        self.type = func_type.return_type.as_returned_type()
         self.result_ctype = self.type
         self.function = PythonCapiFunctionNode(
             pos, py_name, function_name, func_type,
@@ -11346,6 +11350,78 @@ class SizeofVarNode(SizeofNode):
         pass
 
 
+class ConsumeNode(ExprNode):
+    #  Consume expression
+    #
+    #  operand   ExprNode
+
+    subexprs = ['operand']
+    generate_runtime_check = True
+    operand_is_named = True
+
+    def infer_type(self, env):
+        operand_type = self.operand.infer_type(env)
+        if operand_type.is_cyp_class:
+            return PyrexTypes.cyp_class_qualified_type(operand_type, 'iso~')
+        else:
+            return operand_type
+
+    def analyse_types(self, env):
+        self.operand = self.operand.analyse_types(env)
+        operand_type = self.operand.type
+        if not operand_type.is_cyp_class:
+            error(self.pos, "Can only consume cypclass")
+            self.type = PyrexTypes.error_type
+            return self
+        if self.operand.is_name or self.operand.is_attribute:
+            self.is_temp = self.operand_is_named = True
+            # We steal the reference of the operand.
+            self.use_managed_ref = False
+        if operand_type.is_qualified_cyp_class:
+            if operand_type.qualifier == 'iso!':
+                error(self.pos, "Cannot consume iso!")
+                self.type = PyrexTypes.error_type
+                return self
+            self.generate_runtime_check = operand_type.qualifier not in ('iso', 'iso~')
+            if operand_type.qualifier == 'iso~':
+                self.type = operand_type
+            else:
+                self.type = PyrexTypes.cyp_class_qualified_type(operand_type.qual_base_type, 'iso~')
+        else:
+            self.type = PyrexTypes.cyp_class_qualified_type(operand_type, 'iso~')
+        return self
+
+    def may_be_none(self):
+        return self.operand.may_be_none()
+
+    def is_simple(self):
+        return self.operand.is_simple()
+
+    def make_owned_reference(self, code):
+        # We steal the reference of the consumed operand.
+        pass
+
+    def calculate_result_code(self):
+        if self.generate_runtime_check:
+            # TODO: generate runtime check for isolation
+            return self.operand.result()
+        else:
+            return self.operand.result()
+
+    def generate_result_code(self, code):
+        if self.is_temp:
+            operand_result = self.operand.result()
+            code.putln("%s = %s;" % (self.result(), operand_result))
+            if self.generate_runtime_check:
+                # TODO: generate runtime check for isolation
+                pass
+            # We steal the reference of the operand.
+            code.putln("%s = NULL;" % operand_result)
+        if self.operand.is_temp:
+            # TODO: steal the reference of the operand instead
+            code.put_incref(self.result(), self.type)
+
+
 class TypeidNode(ExprNode):
     #  C++ typeid operator applied to a type or variable
     #
@@ -11634,7 +11710,7 @@ class BinopNode(ExprNode):
         else:
             self.operand1 = self.operand1.coerce_to(func_type.args[0].type, env)
             self.operand2 = self.operand2.coerce_to(func_type.args[1].type, env)
-        self.type = func_type.return_type
+        self.type = func_type.return_type.as_returned_type()
 
     def result_type(self, type1, type2, env):
         if self.is_pythran_operation_types(type1, type2, env):
@@ -13330,7 +13406,7 @@ class PrimaryCmpNode(ExprNode, CmpNode):
         else:
             self.operand1 = self.operand1.coerce_to(func_type.args[0].type, env)
             self.operand2 = self.operand2.coerce_to(func_type.args[1].type, env)
-        self.type = func_type.return_type
+        self.type = func_type.return_type.as_returned_type()
 
     def analyse_memoryviewslice_comparison(self, env):
         have_none = self.operand1.is_none or self.operand2.is_none

Cython/Compiler/Parsing.py

@@ -309,6 +309,8 @@ def _p_factor(s):
             return p_typecast(s)
         elif sy == 'IDENT' and s.systring == "sizeof":
             return p_sizeof(s)
+        elif sy == 'IDENT' and s.systring == "consume":
+            return p_consume(s)
     return p_power(s)
 
 def p_typecast(s):
@@ -357,6 +359,13 @@ def p_sizeof(s):
     s.expect(')')
     return node
 
+def p_consume(s):
+    # s.sy == ident "consume"
+    pos = s.position()
+    s.next()
+    operand = p_factor(s)
+    return ExprNodes.ConsumeNode(pos, operand = operand)
+
 
 def p_yield_expression(s):
     # s.sy == "yield"
@@ -2535,7 +2544,7 @@ def p_c_simple_base_type(s, self_flag, nonempty, templates = None):
             base_type=base_type, is_const=is_const, is_volatile=is_volatile)
 
     # Handle cypclass qualifiers
-    if s.sy == 'IDENT' and s.systring in ('active',):
+    if s.sy == 'IDENT' and s.systring in ('active', 'iso'):
         qualifier = s.systring
         s.next()
         base_type = p_c_base_type(s, self_flag=self_flag, nonempty=nonempty, templates=templates)

Cython/Compiler/PyrexTypes.py

@@ -228,6 +228,9 @@ class PyrexType(BaseType):
     #    Coerces array and C function types into pointer type for use as
     #    a formal argument type.
     #
+    #  as_returned_type():
+    #    Potentially annotates function call return types as pure rvalues.
+    #
 
     is_pyobject = 0
     is_unspecified = 0
@@ -316,6 +319,9 @@ class PyrexType(BaseType):
     def as_argument_type(self):
         return self
 
+    def as_returned_type(self):
+        return self
+
     def is_complete(self):
         # A type is incomplete if it is an unsized array,
         # a struct whose attributes are not defined, etc.
@@ -648,6 +654,12 @@ class CheckedResultType(BaseType):
     def as_argument_type(self):
         return self.checked_base_type.as_argument_type()
 
+    def as_returned_type(self):
+        returned_base_type = self.checked_base_type.as_returned_type()
+        if returned_base_type.same_as(self.checked_base_type):
+            return self
+        return CheckedResultType(self.pos, returned_base_type)
+
     def cast_code(self, expr_code):
         return self.checked_base_type.cast_code(expr_code)
 
@@ -1265,6 +1277,9 @@ class BufferType(BaseType):
     def as_argument_type(self):
         return self
 
+    def as_returned_type(self):
+        return self
+
     def specialize(self, values):
         dtype = self.dtype.specialize(values)
         if dtype is not self.dtype:
@@ -1956,6 +1971,9 @@ class QualifiedMethodType(BaseType):
     def as_argument_type(self):
         return c_ptr_type(self)
 
+    def as_returned_type(self):
+        return self
+
     # All that follows is just to behave exactly like the underlying function type
 
     def __getattr__(self, name):
@@ -3000,6 +3018,13 @@ class CReferenceType(BaseType):
         else:
             return type(self)(base_type)
 
+    def as_returned_type(self):
+        returned_base_type = self.ref_base_type.as_returned_type()
+        if returned_base_type == self.ref_base_type:
+            return self
+        else:
+            return CReferenceType(returned_base_type)
+
     def deduce_template_params(self, actual):
         return self.ref_base_type.deduce_template_params(actual)
 
@@ -4618,6 +4643,8 @@ class CypClassType(CppClassType):
     def assignable_from_resolved_type(self, other_type):
         if other_type.is_const_cyp_class:
             return 0
+        if other_type.is_qualified_cyp_class and other_type.qualifier != 'iso~':
+            return 0
         if other_type.is_ptr and other_type.base_type.is_cpp_class and other_type.base_type.is_subclass(self) or other_type.is_null_ptr:
             return 1
         return super(CypClassType, self).assignable_from_resolved_type(other_type)
@@ -4733,6 +4760,9 @@ class ConstCypclassType(BaseType):
     def as_argument_type(self):
         return self
 
+    def as_returned_type(self):
+        return self
+
     def deduce_template_params(self, actual):
         return self.const_base_type.deduce_template_params(actual)
 
@@ -4772,13 +4802,20 @@ class ConstCypclassType(BaseType):
 class QualifiedCypclassType(BaseType):
     "A qualified cypclass reference"
 
-    # qualifier     string      the qualifier keyword
+    # qualifier     string      the qualifier keyword: ('active' | 'iso' | 'iso~' | 'iso!' )
 
     subtypes = ['qual_base_type']
 
     is_cyp_class = 1
     is_qualified_cyp_class = 1
 
+    assignable_to = {
+        'active': ('active', 'iso~'),
+        'iso': ('iso~',),
+        'iso~': (),
+        'iso!': (),
+    }
+
     def __init__(self, base_type, qualifier):
         assert base_type.is_cyp_class
         self.qual_base_type = base_type
@@ -4830,6 +4867,11 @@ class QualifiedCypclassType(BaseType):
     def as_argument_type(self):
         return self
 
+    def as_returned_type(self):
+        if self.qualifier == 'iso':
+            return QualifiedCypclassType(self.qual_base_type, 'iso~')
+        return self
+
     def deduce_template_params(self, actual):
         return self.qual_base_type.deduce_template_params(actual)
 
@@ -4848,7 +4890,7 @@ class QualifiedCypclassType(BaseType):
         return self.assignable_from_resolved_type(src_type.resolve())
 
     def assignable_from_resolved_type(self, src_type):
-        if src_type.is_qualified_cyp_class and self.qualifier == src_type.qualifier:
+        if src_type.is_qualified_cyp_class and src_type.qualifier in self.assignable_to[self.qualifier]:
             return self.qual_base_type.assignable_from_resolved_type(src_type.qual_base_type)
         return 0
 

Cython/Compiler/Symtab.py

@@ -3272,6 +3272,8 @@ class QualifiedCypclassScope(Scope):
 def qualified_cypclass_scope(base_type_scope, qualifier):
     if qualifier == 'active':
         return ActiveCypclassScope(base_type_scope)
+    elif qualifier.startswith('iso'):
+        return IsoCypclassScope(base_type_scope)
     else:
         return QualifiedCypclassScope(base_type_scope, qualifier)
 
@@ -3293,6 +3295,61 @@ class ActiveCypclassScope(QualifiedCypclassScope):
         return base_entry.active_entry
 
 
+class IsoCypclassScope(QualifiedCypclassScope):
+    def __init__(self, base_type_scope):
+        QualifiedCypclassScope.__init__(self, base_type_scope, 'iso')
+
+    def adapt(self, fieldtype, qualifier='iso'):
+        if fieldtype.is_qualified_cyp_class:
+            # attribute is sendable (either 'iso' or 'active')
+            return fieldtype
+        elif fieldtype.is_cyp_class:
+            # viewpoint adaptation
+            return PyrexTypes.cyp_class_qualified_type(fieldtype, qualifier)
+        else:
+            return fieldtype
+
+    def adapt_arg_type(self, arg):
+        arg = copy.copy(arg)
+        arg.type = self.adapt(arg.type)
+        return arg
+
+    def adapt_method_entry(self, base_entry):
+        iso_method_type = copy.copy(base_entry.type)
+        # The return type should be treated as 'iso' but cannot be consumed
+        return_type = self.adapt(base_entry.type.return_type, qualifier='iso!')
+        iso_method_type.return_type = return_type
+        iso_method_type.args = [self.adapt_arg_type(arg) for arg in base_entry.type.args]
+        if hasattr(base_entry.type, 'op_arg_struct'):
+            iso_method_type.op_arg_struct = entry.type.op_arg_struct
+        entry = copy.copy(base_entry)
+        entry.type = iso_method_type
+        return entry
+
+    def resolve(self, name):
+        base_entry = self.base_type_scope.lookup_here(name)
+        if base_entry is None:
+            return None
+        if base_entry.is_type:
+            return base_entry
+        if base_entry.is_cfunction:
+            iso_alternatives = []
+            for e in base_entry.all_alternatives():
+                iso_entry = self.adapt_method_entry(e)
+                iso_alternatives.append(iso_entry)
+                iso_entry.overloaded_alternatives = iso_alternatives
+            return iso_alternatives[0]
+        else:
+            base_entry_type = base_entry.type
+            adapted_type = self.adapt(base_entry_type)
+            if adapted_type is base_entry_type:
+                return base_entry
+            else:
+                entry = copy.copy(base_entry)
+                entry.type = adapted_type
+                return entry
+
+
 class TemplateScope(Scope):
     def __init__(self, name, outer_scope):
         Scope.__init__(self, name, outer_scope, None)

Cython/Compiler/TypeInference.py

@@ -538,6 +538,8 @@ def simply_type(result_type, pos):
         result_type = result_type.ref_base_type
     if result_type.is_cv_qualified:
         result_type = result_type.cv_base_type
+    if result_type.is_qualified_cyp_class and result_type.qualifier == 'iso~':
+        result_type = PyrexTypes.cyp_class_qualified_type(result_type.qual_base_type, 'iso')
     if result_type.is_cpp_class:
         result_type.check_nullary_constructor(pos)
     if result_type.is_array:

Cython/Utility/CyObjects.cpp

@@ -439,7 +439,7 @@
 
         /*
             * Check whether a CyObject is an instance of a given type.
-            * 
+            *
             * template:
             *  - T: the type
             */
@@ -463,7 +463,7 @@
             * Cast from CyObject to PyObject:
             *  - borrow an atomic reference
             *  - return a new Python reference
-            * 
+            *
             * Note: an optimisation could be to steal a reference but only decrement
             * when Python already has a reference, because calls to this function
             * are likely (certain even?) to be followed by a Cy_DECREF; stealing the
@@ -488,11 +488,11 @@
             * Cast from PyObject to CyObject:
             *  - borrow an Python reference
             *  - return a new atomic reference
-            * 
+            *
             * In case of conversion failure:
             *  - raise an exception
             *  - return NULL
-            * 
+            *
             * template:
             *  - U: the type of the underlying cypclass
             */
@@ -791,7 +791,7 @@ void CyLock::unwlock() {
 /*
  * Atomic counter increment and decrement implementation based on
  * @source: https://www.boost.org/doc/libs/1_73_0/doc/html/atomic/usage_examples.html
- */ 
+ */
 void CyObject::CyObject_INCREF() const
 {
     this->nogil_ob_refcnt.fetch_add(1, std::memory_order_relaxed);