Implement runtime isolation check on consuming non 'iso' cypclass

Cython/Compiler/ExprNodes.py

@@ -11356,10 +11356,11 @@ class ConsumeNode(ExprNode):
     #  Consume expression
     #
     #  operand   ExprNode
+    #
+    #  generate_runtime_check   boolean     used internally
+    #  operand_is_named         boolean     used internally
     subexprs = ['operand']
-    generate_runtime_check = True
-    operand_is_named = True
     def infer_type(self, env):
         operand_type = self.operand.infer_type(env)
@@ -11375,10 +11376,6 @@ class ConsumeNode(ExprNode):
             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!")
@@ -11390,7 +11387,13 @@ class ConsumeNode(ExprNode):
             else:
                 self.type = PyrexTypes.cyp_class_qualified_type(operand_type.qual_base_type, 'iso~')
         else:
+            self.generate_runtime_check = True
             self.type = PyrexTypes.cyp_class_qualified_type(operand_type, 'iso~')
+        self.operand_is_named = self.operand.is_name or self.operand.is_attribute
+        self.is_temp = self.operand_is_named or self.generate_runtime_check
+        if self.is_temp:
+            # We steal the reference of the operand.
+            self.use_managed_ref = False
         return self
     def may_be_none(self):
@@ -11404,19 +11407,16 @@ class ConsumeNode(ExprNode):
         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()
+        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
+                code.putln("if (!%s->CyObject_iso()) {" % self.result())
+                code.putln("std::terminate();")
+                code.putln("}")
             # We steal the reference of the operand.
             code.putln("%s = NULL;" % operand_result)
         if self.operand.is_temp:

Cython/Compiler/ModuleNode.py

@@ -937,6 +937,8 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
                     self.generate_cyp_class_activated_methods(entry, code)
                 # Generate cypclass attr destructor
                 self.generate_cyp_class_attrs_destructor_definition(entry, code)
+                # Generate cypclass traverse method and isolation check method
+                self.generate_cyp_class_traverse_and_iso_definition(entry, code)
                 # Generate wrapper constructor
                 wrapper = scope.lookup_here("<constructor>")
                 constructor = scope.lookup_here("<init>")
@@ -967,6 +969,41 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
                 code.putln("Cy_XDECREF(this->%s);" % attr.cname)
             code.putln("}")
 
+    def generate_cyp_class_traverse_and_iso_definition(self, entry, code):
+        """
+            Generate traverse method and isolation check method definition for the given cypclass entry.
+        """
+
+        scope = entry.type.scope
+        all_cypclass_attrs = [e for e in scope.entries.values()
+                                if e.type.is_cyp_class and not e.name == "this"
+                                and not e.is_type]
+        # potential template
+        if entry.type.templates:
+            templates_code = "template <typename %s>" % ", typename ".join(t.name for t in entry.type.templates)
+        else:
+            templates_code = None
+        # traverse method
+        namespace = entry.type.empty_declaration_code()
+        if templates_code:
+            code.putln(templates_code)
+        code.putln("int %s::CyObject_traverse(void *(*visit)(const CyObject *o, void *arg), void *arg) const" % namespace)
+        code.putln("{")
+        for attr in all_cypclass_attrs:
+            code.putln("if (void *ret = visit(this->%s, arg)) return (int) (intptr_t) ret;" % attr.cname)
+        code.putln("return 0;")
+        code.putln("}")
+        # isolation check method
+        if templates_code:
+            code.putln(templates_code)
+        code.putln("int %s::CyObject_iso() const" % namespace)
+        code.putln("{")
+        if all_cypclass_attrs:
+            code.putln("return __Pyx_CyObject_owning(this) == 1;")
+        else:
+            code.putln("return this->CyObject_GETREF() == 1;")
+        code.putln("}")
+
     def generate_cyp_class_activated_methods(self, entry, code):
         """
             Generate activated cypclass methods.
@@ -1459,10 +1496,6 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
         code.putln("Py_TYPE(wrapper) = %s;" % wrapper_type.typeptr_cname)
         code.putln("}")
 
-
-
-
-
     def generate_typedef(self, entry, code):
         base_type = entry.type.typedef_base_type
         enclosing_scope = entry.scope
@@ -1632,6 +1665,12 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
                     arg_names = []
                     generate_cpp_constructor_code(arg_decls, arg_names, is_implementing, py_attrs, constructor)
 
+            if type.is_cyp_class:
+                # Declare the method to check isolation
+                code.putln("virtual int CyObject_iso() const;")
+                # Declare the traverse method
+                code.putln("virtual int CyObject_traverse(void *(*visit)(const CyObject *o, void *arg), void *arg) const;")
+
             if type.is_cyp_class and cypclass_attrs:
                 # Declaring a small destruction handler which will always try to Cy_XDECREF
                 # every cypclass attribute. This handler is defined after all class definition.

Cython/Utility/CyObjects.cpp

@@ -83,10 +83,21 @@
             private:
                 mutable std::atomic_int nogil_ob_refcnt;
                 mutable CyLock ob_lock;
+
             public:
-                CyObject(): nogil_ob_refcnt(1) {}
+                mutable const CyObject * __next;
+                mutable int __refcnt;
+                CyObject(): nogil_ob_refcnt(1), __next(NULL), __refcnt(0) {}
                 virtual ~CyObject() {}
 
+                /* Object graph inspection methods */
+                virtual int CyObject_iso() const {
+                    return this->nogil_ob_refcnt == 1;
+                }
+                virtual int CyObject_traverse(void *(*visit)(const CyObject *o, void *arg), void *arg) const {
+                    return 0;
+                }
+
                 /* Locking methods */
                 void CyObject_RLOCK(const char * context) const;
                 void CyObject_WLOCK(const char * context) const;
@@ -475,6 +486,67 @@
             return ob;
         }
 
+        /*
+            * Visit callback to collect reachable fields.
+            */
+        static void *__Pyx_CyObject_visit_collect(const CyObject *ob, void *arg) {
+            if (!ob)
+                return 0;
+            if (ob->__refcnt)
+                return 0;
+            ob->__refcnt = ob->CyObject_GETREF();
+            const CyObject *head = reinterpret_cast<CyObject *>(arg);
+            const CyObject *tmp = head->__next;
+            ob->__next = tmp;
+            head->__next = ob;
+            return 0;
+        }
+
+        /*
+            * Visit callback to decref reachable fields.
+            */
+        static void *__Pyx_CyObject_visit_decref(const CyObject *ob, void *arg) {
+            (void) arg;
+            if (!ob)
+                return 0;
+            ob->__refcnt -= 1;
+            return 0;
+        }
+
+        /*
+            * Check if a CyObject is owning.
+            */
+        static inline int __Pyx_CyObject_owning(const CyObject *root) {
+            const CyObject *current;
+            bool owning = true;
+            int owners;
+            /* Mark the root as already visited */
+            root->__refcnt = root->CyObject_GETREF();
+            /* Collect the reachable objects */
+            for(current = root; current != NULL; current = current->__next) {
+                current->CyObject_traverse(__Pyx_CyObject_visit_collect, (void*)current);
+            }
+            /* Decref the reachable objects */
+            for(current = root; current != NULL; current = current->__next) {
+                current->CyObject_traverse(__Pyx_CyObject_visit_decref, (void*)current);
+            }
+            /* Search for externally reachable object */
+            for(current = root->__next; current != NULL; current = current->__next) {
+                if (current->__refcnt)
+                    owning = false;
+            }
+            /* Count external potential owners */
+            owners = root->__refcnt;
+            /* Cleanup */
+            for(current = root; current != NULL;) {
+                current->__refcnt = 0;
+                const CyObject *next = current->__next;
+                current->__next = NULL;
+                current = next;
+            }
+            return owning ? owners : 0;
+        }
+
         /*
             * Cast from CyObject to PyObject:
             *  - borrow an atomic reference