Implement CONSTRUCTOR/DESTRUCTOR. (#1424)

src/codegen/codegen_neuron_cpp_visitor.cpp

@@ -1120,10 +1120,16 @@ void CodegenNeuronCppVisitor::print_mechanism_register() {
             "_pointtype = point_register_mech({}, _hoc_create_pnt, _hoc_destroy_pnt, "
             "_member_func);",
             register_mech_args);
+
+        if (info.destructor_node) {
+            printer->fmt_line("register_destructor({});",
+                              method_name(naming::NRN_DESTRUCTOR_METHOD));
+        }
     } else {
         printer->fmt_line("register_mech({});", register_mech_args);
     }
 
+
     if (info.thread_callback_register) {
         printer->fmt_line("_extcall_thread.resize({});", info.thread_data_index + 1);
         printer->fmt_line("thread_mem_init(_extcall_thread.data());");
@@ -1560,21 +1566,55 @@ void CodegenNeuronCppVisitor::print_nrn_jacob() {
 }
 
 
-/// TODO: Edit for NEURON
+void CodegenNeuronCppVisitor::print_callable_preamble_from_prop() {
+    printer->add_line("Datum* _ppvar = _nrn_mechanism_access_dparam(prop);");
+    printer->add_line("_nrn_mechanism_cache_instance _lmc{prop};");
+    printer->add_line("const size_t id = 0;");
+
+    printer->fmt_line("auto inst = make_instance_{}(_lmc);", info.mod_suffix);
+    if (!info.artificial_cell) {
+        printer->fmt_line("auto node_data = make_node_data_{}(prop);", info.mod_suffix);
+    }
+
+    if (!codegen_thread_variables.empty()) {
+        printer->fmt_line("auto _thread_vars = {}({}_global.thread_data);",
+                          thread_variables_struct(),
+                          info.mod_suffix);
+    }
+
+    printer->add_newline();
+}
+
+
 void CodegenNeuronCppVisitor::print_nrn_constructor() {
-    return;
+    if (info.constructor_node) {
+        printer->fmt_push_block("void {}(Prop* prop)", method_name(naming::NRN_CONSTRUCTOR_METHOD));
+
+        print_callable_preamble_from_prop();
+
+        auto block = info.constructor_node->get_statement_block();
+        print_statement_block(*block, false, false);
+
+        printer->pop_block();
+    }
 }
 
 
 void CodegenNeuronCppVisitor::print_nrn_destructor() {
-    printer->fmt_push_block("void {}(Prop* _prop)", method_name(naming::NRN_DESTRUCTOR_METHOD));
-    printer->add_line("Datum* _ppvar = _nrn_mechanism_access_dparam(_prop);");
+    printer->fmt_push_block("void {}(Prop* prop)", method_name(naming::NRN_DESTRUCTOR_METHOD));
+    print_callable_preamble_from_prop();
 
     for (const auto& rv: info.random_variables) {
         printer->fmt_line("nrnran123_deletestream((nrnran123_State*) {});",
                           get_variable_name(get_name(rv), false));
     }
 
+
+    if (info.destructor_node) {
+        auto block = info.destructor_node->get_statement_block();
+        print_statement_block(*block, false, false);
+    }
+
     printer->pop_block();
 }
 
@@ -1699,6 +1739,15 @@ void CodegenNeuronCppVisitor::print_nrn_alloc() {
                           method_name(naming::NRN_DESTRUCTOR_METHOD));
     }
 
+    if (info.point_process || info.artificial_cell) {
+        printer->fmt_push_block("if(!nrn_point_prop_)");
+
+        if (info.constructor_node) {
+            printer->fmt_line("{}(_prop);", method_name(naming::NRN_CONSTRUCTOR_METHOD));
+        }
+        printer->pop_block();
+    }
+
     printer->pop_block();
 }
 
@@ -2089,6 +2138,7 @@ void CodegenNeuronCppVisitor::print_codegen_routines() {
     print_prcellstate_macros();
     print_mechanism_info();
     print_data_structures(true);
+    print_nrn_constructor();
     print_nrn_destructor();
     print_nrn_alloc();
     print_function_prototypes();

src/codegen/codegen_neuron_cpp_visitor.hpp

@@ -491,6 +491,10 @@ class CodegenNeuronCppVisitor: public CodegenCppVisitor {
      */
     void print_nrn_constructor() override;
 
+    /**
+     * Print the set of common variables from a `Prop` only.
+     */
+    void print_callable_preamble_from_prop();
 
     /**
      * Print nrn_destructor function definition

test/usecases/CMakeLists.txt

@@ -2,6 +2,7 @@ set(NMODL_USECASE_DIRS
     solve
     constant
     electrode_current
+    constructor
     function
     procedure
     global

test/usecases/constructor/art_ctor.mod

@@ -0,0 +1,17 @@
+NEURON {
+    ARTIFICIAL_CELL art_ctor
+    GLOBAL ctor_calls, dtor_calls
+}
+
+ASSIGNED {
+  ctor_calls
+  dtor_calls
+}
+
+CONSTRUCTOR {
+  ctor_calls = ctor_calls + 1
+}
+
+DESTRUCTOR {
+  dtor_calls = dtor_calls + 1
+}

test/usecases/constructor/ctor.mod

@@ -0,0 +1,17 @@
+NEURON {
+    POINT_PROCESS ctor
+    GLOBAL ctor_calls, dtor_calls
+}
+
+ASSIGNED {
+  ctor_calls
+  dtor_calls
+}
+
+CONSTRUCTOR {
+  ctor_calls = ctor_calls + 1
+}
+
+DESTRUCTOR {
+  dtor_calls = dtor_calls + 1
+}

test/usecases/constructor/test_ctor.py

@@ -0,0 +1,36 @@
+import gc
+
+from neuron import h, gui
+
+
+def allocate_props(n_instances, mech_name):
+    s = h.Section()
+    s.nseg = 1
+
+    for _ in range(n_instances):
+        getattr(h, mech_name)(s(0.5))
+
+
+def assert_equal(actual, expected):
+    assert actual == expected, f"{actual} != {expected}"
+
+
+def check_ctor(n_instances, mech_name):
+    allocate_props(n_instances, mech_name)
+    gc.collect()
+
+    assert_equal(getattr(h, f"ctor_calls_{mech_name}"), n_instances)
+    assert_equal(getattr(h, f"dtor_calls_{mech_name}"), n_instances)
+
+
+def test_ctor():
+    check_ctor(12, "ctor")
+
+
+def test_art_ctor():
+    check_ctor(32, "art_ctor")
+
+
+if __name__ == "__main__":
+    test_ctor()
+    test_art_ctor()