src/ffi: separate compiler_ffi in light/full modules
authorAlexis Laferrière <alexis.laf@xymus.net>
Wed, 6 May 2015 11:47:52 +0000 (07:47 -0400)
committerAlexis Laferrière <alexis.laf@xymus.net>
Fri, 8 May 2015 14:31:53 +0000 (10:31 -0400)
Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

src/compiler/compiler_ffi/compiler_ffi.nit [moved from src/compiler/compiler_ffi.nit with 63% similarity]
src/compiler/compiler_ffi/light.nit [new file with mode: 0644]

similarity index 63%
rename from src/compiler/compiler_ffi.nit
rename to src/compiler/compiler_ffi/compiler_ffi.nit
index 42423f9..9b0dc27 100644 (file)
 # FFI support for the compilers
 module compiler_ffi
 
-intrude import abstract_compiler
-intrude import ffi
+intrude import light
 import nitni
 
 redef class MModule
        private var foreign_callbacks = new ForeignCallbackSet
-       var nitni_ccu: nullable CCompilationUnit = null
-
-       private fun nmodule(v: AbstractCompilerVisitor): nullable AModule
-       do
-               return v.compiler.modelbuilder.mmodule2node(self)
-       end
 
        redef fun finalize_ffi(compiler: AbstractCompiler)
        do
                if not uses_ffi then return
 
-               var v = compiler.new_visitor
-               var n = nmodule(v)
-               if n == null then return
-               n.ensure_compile_ffi_wrapper
-               finalize_ffi_wrapper(v.compiler.modelbuilder.compile_dir, v.compiler.mainmodule)
-               for file in ffi_files do v.compiler.extern_bodies.add(file)
-
-               ensure_compile_nitni_base(v)
-
-               nitni_ccu.header_c_types.add("#include \"{c_name}._ffi.h\"\n")
-               nitni_ccu.header_c_types.add """
-extern void nitni_global_ref_incr(void*);
-extern void nitni_global_ref_decr(void*);
-"""
-
-               var cflags = self.cflags[""].join(" ")
-               nitni_ccu.write_as_nitni(self, v.compiler.modelbuilder.compile_dir)
-
-               for file in nitni_ccu.files do
-                       var f = new ExternCFile(file, cflags)
-                       f.pkgconfigs.add_all pkgconfigs
-                       v.compiler.extern_bodies.add(f)
-               end
+               super
 
-               # reset FFI things so the next compilation job, if any, starts with a clean context
-               # FIXME clean and rationalize this
-               nitni_ccu = null
-               compiled_ffi_methods.clear
-               ffi_ccu = null
-               ffi_files.clear
                compiled_callbacks.clear
                #Do not reset `foreign_callbacks` and `ffi_callbacks` because they are computed in previous phases
        end
 
-       private fun ensure_compile_nitni_base(v: AbstractCompilerVisitor)
-       do
-               if nitni_ccu != null then return
-
-               nitni_ccu = new CCompilationUnit
-       end
-
-       redef fun collect_linker_libs
-       do
-               if not self.ldflags.keys.has("") then return null
-               return self.ldflags[""]
-       end
-
        private var compiled_callbacks = new Array[NitniCallback]
 
        # Returns true if callbacks has yet to be generated and register it as being generated
@@ -93,23 +45,12 @@ extern void nitni_global_ref_decr(void*);
 end
 
 redef class AMethPropdef
-       private fun compile_ffi_support_to_c(v: AbstractCompilerVisitor)
+       redef fun compile_ffi_support_to_c(v)
        do
+               super
+
                var mmodule = mpropdef.mclassdef.mmodule
                var mainmodule = v.compiler.mainmodule
-               var amodule = v.compiler.modelbuilder.mmodule2node(mmodule)
-               var mclass_type = mpropdef.mclassdef.bound_mtype
-
-               # Declare as extern
-               var csignature = mpropdef.mproperty.build_csignature(mclass_type, mmodule, "___impl", long_signature, internal_call_context)
-               v.declare_once("{csignature};")
-
-               # FFI part
-               amodule.ensure_compile_ffi_wrapper
-               compile_ffi_method(mmodule)
-
-               # nitni - Compile missing callbacks
-               mmodule.ensure_compile_nitni_base(v)
                var ccu = mmodule.nitni_ccu.as(not null)
 
                for mtype in foreign_callbacks.types do
@@ -137,178 +78,71 @@ redef class AMethPropdef
                # manage nitni callback set
                mmodule.foreign_callbacks.join(foreign_callbacks)
        end
+end
 
-       redef fun compile_externmeth_to_c(v, mpropdef, arguments)
+redef class MExplicitCall
+       private fun compile_extern_callback(v: AbstractCompilerVisitor, ccu: CCompilationUnit, compile_implementation_too: Bool)
        do
-               # if using the old native interface fallback on previous implementation
-               if n_extern_code_block == null then return super
+               var mproperty = mproperty
+               assert mproperty isa MMethod
 
-               var mmodule = mpropdef.mclassdef.mmodule
-               mmodule.uses_ffi = true
+               # In nitni files, declare internal function as extern
+               var full_friendly_csignature = mproperty.build_csignature(recv_mtype, v.compiler.mainmodule, null, long_signature, internal_call_context)
+               ccu.header_decl.add("extern {full_friendly_csignature};\n")
 
-               var mclass_type = mpropdef.mclassdef.bound_mtype
+               if not compile_implementation_too then return
 
-               # Outgoing code in compiler
-               var externname = mpropdef.mproperty.build_cname(mpropdef.mclassdef.bound_mtype, mmodule, "___impl", long_signature)
-               var recv_var: nullable RuntimeVariable = null
-               var return_mtype = mpropdef.msignature.return_mtype
-               if return_mtype != null then
-                       return_mtype = return_mtype.anchor_to(mmodule, mclass_type)
-                       recv_var = v.new_var(return_mtype)
-               end
+               # Internally, implement internal function
+               var nitni_visitor = v.compiler.new_visitor
+               nitni_visitor.frame = v.frame
+               var msignature = mproperty.lookup_first_definition(v.compiler.mainmodule, recv_mtype).msignature
+               var csignature_blind = mproperty.build_csignature(recv_mtype, v.compiler.mainmodule, null, long_signature, internal_call_context)
 
-               v.adapt_signature(mpropdef, arguments)
-               v.unbox_signature_extern(mpropdef, arguments)
-
-               var arguments_for_c = new Array[String]
-               for a in [0..arguments.length[ do
-                       var arg = arguments[a]
-                       var param_mtype: MType
-                       if a == 0 then
-                               param_mtype = mpropdef.mclassdef.mclass.mclass_type
-                       else param_mtype = mpropdef.msignature.mparameters[a-1].mtype
-
-                       param_mtype = param_mtype.anchor_to(mmodule, mclass_type)
-
-                       if param_mtype.is_cprimitive then
-                               arguments_for_c.add(arg.name)
-                       else
-                               v.add("struct nitni_instance* var_for_c_{a};")
-                               v.add("var_for_c_{a} = nit_alloc(sizeof(struct nitni_instance));")
-                               v.add("var_for_c_{a}->value = {arg.name};")
-                               arguments_for_c.add("var_for_c_{a}")
-                       end
-               end
+               nitni_visitor.add_decl("/* nitni callback for {mproperty.full_name} */")
+               nitni_visitor.add_decl("{csignature_blind} \{")
 
-               if recv_var == null then
-                       v.add("{externname}({arguments_for_c.join(", ")});")
+               var vars = new Array[RuntimeVariable]
+               var mtype: MType = recv_mtype
+               var recv_var = null
+               if mproperty.is_init then
+                       var recv_mtype = recv_mtype
+                       recv_var = nitni_visitor.init_instance_or_extern(recv_mtype)
+                       nitni_visitor.add("{mtype.ctype} recv /* var self: {mtype} */;")
+                       nitni_visitor.add("recv = {recv_var};")
                else
-                       assert return_mtype != null
-                       if return_mtype.is_cprimitive then
-                               v.add("{recv_var} = {externname}({arguments_for_c.join(", ")});")
-                       else
-                               v.add("struct nitni_instance* ret_var;")
-                               v.add("ret_var = {externname}({arguments_for_c.join(", ")});")
-                               v.add("{recv_var} = ret_var->value;")
-                       end
-                       recv_var = v.box_extern(recv_var, return_mtype)
-                       v.ret(recv_var)
+                       mtype = mtype.anchor_to(v.compiler.mainmodule, recv_mtype)
+                       recv_var = nitni_visitor.var_from_c("recv", mtype)
+                       recv_var = nitni_visitor.box_extern(recv_var, mtype)
                end
 
-               compile_ffi_support_to_c(v)
-               return true
-       end
-
-       redef fun compile_externinit_to_c(v, mpropdef, arguments)
-       do
-               # if using the old native interface fallback on previous implementation
-               if n_extern_code_block == null then return super
-
-               var mmodule = mpropdef.mclassdef.mmodule
-               mmodule.uses_ffi = true
-
-               var mclass_type = mpropdef.mclassdef.bound_mtype
-
-               var externname = mpropdef.mproperty.build_cname(mpropdef.mclassdef.bound_mtype, mmodule, "___impl", long_signature)
-               var return_mtype = arguments.first.mtype
-               var recv_var = v.new_var(return_mtype)
-
-               v.adapt_signature(mpropdef, arguments)
-               v.unbox_signature_extern(mpropdef, arguments)
-
-               arguments.shift
-
-               var arguments_for_c = new Array[String]
-               for a in [0..arguments.length[ do
-                       var arg = arguments[a]
-                       var param_mtype: MType
-                       param_mtype = mpropdef.msignature.mparameters[a].mtype
-                       param_mtype = param_mtype.anchor_to(mmodule, mclass_type)
-
-                       if param_mtype.is_cprimitive then
-                               arguments_for_c.add(arg.name)
-                       else
-                               v.add("struct nitni_instance* var_for_c_{a};")
-                               v.add("var_for_c_{a} = nit_alloc(sizeof(struct nitni_instance));")
-                               v.add("var_for_c_{a}->value = {arg.name};")
-                               arguments_for_c.add("var_for_c_{a}")
-                       end
-               end
+               vars.add(recv_var)
 
-               if return_mtype.is_cprimitive then
-                       v.add("{recv_var} = {externname}({arguments_for_c.join(", ")});")
-               else
-                       v.add("struct nitni_instance* ret_var;")
-                       v.add("ret_var = {externname}({arguments_for_c.join(", ")});")
-                       v.add("{recv_var} = ret_var->value;")
+               for p in msignature.mparameters do
+                       var arg_mtype = p.mtype.anchor_to(v.compiler.mainmodule, recv_mtype)
+                       var arg = nitni_visitor.var_from_c(p.name, arg_mtype)
+                       arg = nitni_visitor.box_extern(arg, arg_mtype)
+                       vars.add(arg)
                end
-               recv_var = v.box_extern(recv_var, return_mtype)
-               v.ret(recv_var)
 
-               compile_ffi_support_to_c(v)
-               return true
-       end
-end
-
-redef class CCompilationUnit
-       fun write_as_nitni(mmodule: MModule, compdir: String)
-       do
-               var base_name = "{mmodule.c_name}._nitni"
-
-               var h_file = "{base_name}.h"
-               write_header_to_file( mmodule, "{compdir}/{h_file}", new Array[String],
-                       "{mmodule.c_name.to_s.to_upper}_NITG_NITNI_H")
-
-               var c_file = "{base_name}.c"
-               write_body_to_file( mmodule, "{compdir}/{c_file}", ["\"{h_file}\""] )
-
-               files.add( "{compdir}/{c_file}" )
-       end
-end
-
-redef class AbstractCompiler
-       # Cache to avoid multiple compilation of NULL values
-       # see FIXME in `MNullableType#compile_extern_helper_functions`
-       private var compiled_null_types = new Array[MNullableType]
-end
+               var ret_var = nitni_visitor.send(mproperty, vars)
 
-redef class AbstractCompilerVisitor
-       # Create a `RuntimeVariable` for this C variable originating from C user code
-       private fun var_from_c(name: String, mtype: MType): RuntimeVariable
-       do
-               if mtype.is_cprimitive then
-                       return new RuntimeVariable(name, mtype, mtype)
-               else
-                       return new RuntimeVariable("{name}->value", mtype, mtype)
+               var return_mtype = msignature.return_mtype
+               if mproperty.is_init then
+                       if recv_mtype.mclass.kind != extern_kind then ret_var = recv_var
+                       return_mtype = recv_mtype
                end
-       end
-
-       # Return a `RuntimeVarible` to C user code
-       private fun ret_to_c(src: RuntimeVariable, mtype: MType)
-       do
-               if mtype.is_cprimitive then
-                       add("return {src};")
-               else
-                       add("struct nitni_instance* ret_for_c;")
-                       add("ret_for_c = nit_alloc(sizeof(struct nitni_instance));")
-                       add("ret_for_c->value = {src};")
-                       add("return ret_for_c;")
+               if return_mtype != null then
+                       assert ret_var != null
+                       return_mtype = return_mtype.anchor_to(v.compiler.mainmodule, recv_mtype)
+                       ret_var = nitni_visitor.autobox(ret_var, return_mtype)
+                       ret_var = nitni_visitor.unbox_extern(ret_var, return_mtype)
+                       nitni_visitor.ret_to_c(ret_var, return_mtype)
                end
+               nitni_visitor.add("\}")
        end
 end
 
 redef class MType
-       private fun compile_extern_type(v: AbstractCompilerVisitor, ccu: CCompilationUnit)
-       do
-               assert not is_cprimitive
-
-               # define friendly type
-               ccu.header_c_types.add("#ifndef NIT_TYPE_{cname}\n")
-               ccu.header_c_types.add("#define NIT_TYPE_{cname} 1\n")
-               ccu.header_c_types.add("typedef struct nitni_instance *{cname};\n")
-               ccu.header_c_types.add("#endif\n")
-       end
-
        private fun compile_extern_helper_functions(v: AbstractCompilerVisitor, ccu: CCompilationUnit, compile_implementation_too: Bool)
        do
                # actually, we do not need to do anything when using the bohem garbage collector
@@ -362,68 +196,6 @@ redef class MNullableType
        end
 end
 
-redef class MExplicitCall
-       private fun compile_extern_callback(v: AbstractCompilerVisitor, ccu: CCompilationUnit, compile_implementation_too: Bool)
-       do
-               var mproperty = mproperty
-               assert mproperty isa MMethod
-
-               # In nitni files, declare internal function as extern
-               var full_friendly_csignature = mproperty.build_csignature(recv_mtype, v.compiler.mainmodule, null, long_signature, internal_call_context)
-               ccu.header_decl.add("extern {full_friendly_csignature};\n")
-
-               if not compile_implementation_too then return
-
-               # Internally, implement internal function
-               var nitni_visitor = v.compiler.new_visitor
-               nitni_visitor.frame = v.frame
-               var msignature = mproperty.lookup_first_definition(v.compiler.mainmodule, recv_mtype).msignature
-               var csignature_blind = mproperty.build_csignature(recv_mtype, v.compiler.mainmodule, null, long_signature, internal_call_context)
-
-               nitni_visitor.add_decl("/* nitni callback for {mproperty.full_name} */")
-               nitni_visitor.add_decl("{csignature_blind} \{")
-
-               var vars = new Array[RuntimeVariable]
-               var mtype: MType = recv_mtype
-               var recv_var = null
-               if mproperty.is_init then
-                       var recv_mtype = recv_mtype
-                       recv_var = nitni_visitor.init_instance_or_extern(recv_mtype)
-                       nitni_visitor.add("{mtype.ctype} recv /* var self: {mtype} */;")
-                       nitni_visitor.add("recv = {recv_var};")
-               else
-                       mtype = mtype.anchor_to(v.compiler.mainmodule, recv_mtype)
-                       recv_var = nitni_visitor.var_from_c("recv", mtype)
-                       recv_var = nitni_visitor.box_extern(recv_var, mtype)
-               end
-
-               vars.add(recv_var)
-
-               for p in msignature.mparameters do
-                       var arg_mtype = p.mtype.anchor_to(v.compiler.mainmodule, recv_mtype)
-                       var arg = nitni_visitor.var_from_c(p.name, arg_mtype)
-                       arg = nitni_visitor.box_extern(arg, arg_mtype)
-                       vars.add(arg)
-               end
-
-               var ret_var = nitni_visitor.send(mproperty, vars)
-
-               var return_mtype = msignature.return_mtype
-               if mproperty.is_init then
-                       if recv_mtype.mclass.kind != extern_kind then ret_var = recv_var
-                       return_mtype = recv_mtype
-               end
-               if return_mtype != null then
-                       assert ret_var != null
-                       return_mtype = return_mtype.anchor_to(v.compiler.mainmodule, recv_mtype)
-                       ret_var = nitni_visitor.autobox(ret_var, return_mtype)
-                       ret_var = nitni_visitor.unbox_extern(ret_var, return_mtype)
-                       nitni_visitor.ret_to_c(ret_var, return_mtype)
-               end
-               nitni_visitor.add("\}")
-       end
-end
-
 redef class MExplicitSuper
        private fun compile_extern_callback(v: AbstractCompilerVisitor, ccu: CCompilationUnit, compile_implementation_too: Bool)
        do
diff --git a/src/compiler/compiler_ffi/light.nit b/src/compiler/compiler_ffi/light.nit
new file mode 100644 (file)
index 0000000..345377a
--- /dev/null
@@ -0,0 +1,271 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Copyright 2013-2015 Alexis Laferrière <alexis.laf@xymus.net>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# FFI support for the compilers
+module light
+
+intrude import abstract_compiler
+intrude import ffi::light_ffi
+
+redef class MModule
+       var nitni_ccu: nullable CCompilationUnit = null
+
+       private fun nmodule(v: AbstractCompilerVisitor): nullable AModule
+       do
+               return v.compiler.modelbuilder.mmodule2node(self)
+       end
+
+       redef fun finalize_ffi(compiler: AbstractCompiler)
+       do
+               if not uses_ffi then return
+
+               var v = compiler.new_visitor
+               var n = nmodule(v)
+               if n == null then return
+               n.ensure_compile_ffi_wrapper
+               finalize_ffi_wrapper(v.compiler.modelbuilder.compile_dir, v.compiler.mainmodule)
+               for file in ffi_files do v.compiler.extern_bodies.add(file)
+
+               ensure_compile_nitni_base(v)
+
+               nitni_ccu.header_c_types.add("#include \"{c_name}._ffi.h\"\n")
+               nitni_ccu.header_c_types.add """
+extern void nitni_global_ref_incr(void*);
+extern void nitni_global_ref_decr(void*);
+"""
+
+               var cflags = self.cflags[""].join(" ")
+               nitni_ccu.write_as_nitni(self, v.compiler.modelbuilder.compile_dir)
+
+               for file in nitni_ccu.files do
+                       var f = new ExternCFile(file, cflags)
+                       f.pkgconfigs.add_all pkgconfigs
+                       v.compiler.extern_bodies.add(f)
+               end
+
+               # reset FFI things so the next compilation job, if any, starts with a clean context
+               # FIXME clean and rationalize this
+               nitni_ccu = null
+               compiled_ffi_methods.clear
+               ffi_ccu = null
+               ffi_files.clear
+       end
+
+       private fun ensure_compile_nitni_base(v: AbstractCompilerVisitor)
+       do
+               if nitni_ccu != null then return
+
+               nitni_ccu = new CCompilationUnit
+       end
+
+       redef fun collect_linker_libs
+       do
+               if not self.ldflags.keys.has("") then return null
+               return self.ldflags[""]
+       end
+end
+
+redef class AMethPropdef
+       private fun compile_ffi_support_to_c(v: AbstractCompilerVisitor)
+       do
+               var mmodule = mpropdef.mclassdef.mmodule
+               var mainmodule = v.compiler.mainmodule
+               var amodule = v.compiler.modelbuilder.mmodule2node(mmodule)
+               var mclass_type = mpropdef.mclassdef.bound_mtype
+
+               # Declare as extern
+               var csignature = mpropdef.mproperty.build_csignature(mclass_type, mmodule, "___impl", long_signature, internal_call_context)
+               v.declare_once("{csignature};")
+
+               # FFI part
+               amodule.ensure_compile_ffi_wrapper
+               compile_ffi_method(mmodule)
+
+               # nitni - Compile missing callbacks
+               mmodule.ensure_compile_nitni_base(v)
+       end
+
+       redef fun compile_externmeth_to_c(v, mpropdef, arguments)
+       do
+               # if using the old native interface fallback on previous implementation
+               if n_extern_code_block == null then return super
+
+               var mmodule = mpropdef.mclassdef.mmodule
+               mmodule.uses_ffi = true
+
+               var mclass_type = mpropdef.mclassdef.bound_mtype
+
+               # Outgoing code in compiler
+               var externname = mpropdef.mproperty.build_cname(mpropdef.mclassdef.bound_mtype, mmodule, "___impl", long_signature)
+               var recv_var: nullable RuntimeVariable = null
+               var return_mtype = mpropdef.msignature.return_mtype
+               if return_mtype != null then
+                       return_mtype = return_mtype.anchor_to(mmodule, mclass_type)
+                       recv_var = v.new_var(return_mtype)
+               end
+
+               v.adapt_signature(mpropdef, arguments)
+               v.unbox_signature_extern(mpropdef, arguments)
+
+               var arguments_for_c = new Array[String]
+               for a in [0..arguments.length[ do
+                       var arg = arguments[a]
+                       var param_mtype: MType
+                       if a == 0 then
+                               param_mtype = mpropdef.mclassdef.mclass.mclass_type
+                       else param_mtype = mpropdef.msignature.mparameters[a-1].mtype
+
+                       param_mtype = param_mtype.anchor_to(mmodule, mclass_type)
+
+                       if param_mtype.is_cprimitive then
+                               arguments_for_c.add(arg.name)
+                       else
+                               v.add("struct nitni_instance* var_for_c_{a};")
+                               v.add("var_for_c_{a} = nit_alloc(sizeof(struct nitni_instance));")
+                               v.add("var_for_c_{a}->value = {arg.name};")
+                               arguments_for_c.add("var_for_c_{a}")
+                       end
+               end
+
+               if recv_var == null then
+                       v.add("{externname}({arguments_for_c.join(", ")});")
+               else
+                       assert return_mtype != null
+                       if return_mtype.is_cprimitive then
+                               v.add("{recv_var} = {externname}({arguments_for_c.join(", ")});")
+                       else
+                               v.add("struct nitni_instance* ret_var;")
+                               v.add("ret_var = {externname}({arguments_for_c.join(", ")});")
+                               v.add("{recv_var} = ret_var->value;")
+                       end
+                       recv_var = v.box_extern(recv_var, return_mtype)
+                       v.ret(recv_var)
+               end
+
+               compile_ffi_support_to_c(v)
+               return true
+       end
+
+       redef fun compile_externinit_to_c(v, mpropdef, arguments)
+       do
+               # if using the old native interface fallback on previous implementation
+               if n_extern_code_block == null then return super
+
+               var mmodule = mpropdef.mclassdef.mmodule
+               mmodule.uses_ffi = true
+
+               var mclass_type = mpropdef.mclassdef.bound_mtype
+
+               var externname = mpropdef.mproperty.build_cname(mpropdef.mclassdef.bound_mtype, mmodule, "___impl", long_signature)
+               var return_mtype = arguments.first.mtype
+               var recv_var = v.new_var(return_mtype)
+
+               v.adapt_signature(mpropdef, arguments)
+               v.unbox_signature_extern(mpropdef, arguments)
+
+               arguments.shift
+
+               var arguments_for_c = new Array[String]
+               for a in [0..arguments.length[ do
+                       var arg = arguments[a]
+                       var param_mtype: MType
+                       param_mtype = mpropdef.msignature.mparameters[a].mtype
+                       param_mtype = param_mtype.anchor_to(mmodule, mclass_type)
+
+                       if param_mtype.is_cprimitive then
+                               arguments_for_c.add(arg.name)
+                       else
+                               v.add("struct nitni_instance* var_for_c_{a};")
+                               v.add("var_for_c_{a} = nit_alloc(sizeof(struct nitni_instance));")
+                               v.add("var_for_c_{a}->value = {arg.name};")
+                               arguments_for_c.add("var_for_c_{a}")
+                       end
+               end
+
+               if return_mtype.is_cprimitive then
+                       v.add("{recv_var} = {externname}({arguments_for_c.join(", ")});")
+               else
+                       v.add("struct nitni_instance* ret_var;")
+                       v.add("ret_var = {externname}({arguments_for_c.join(", ")});")
+                       v.add("{recv_var} = ret_var->value;")
+               end
+               recv_var = v.box_extern(recv_var, return_mtype)
+               v.ret(recv_var)
+
+               compile_ffi_support_to_c(v)
+               return true
+       end
+end
+
+redef class CCompilationUnit
+       fun write_as_nitni(mmodule: MModule, compdir: String)
+       do
+               var base_name = "{mmodule.c_name}._nitni"
+
+               var h_file = "{base_name}.h"
+               write_header_to_file( mmodule, "{compdir}/{h_file}", new Array[String],
+                       "{mmodule.c_name.to_s.to_upper}_NITG_NITNI_H")
+
+               var c_file = "{base_name}.c"
+               write_body_to_file( mmodule, "{compdir}/{c_file}", ["\"{h_file}\""] )
+
+               files.add( "{compdir}/{c_file}" )
+       end
+end
+
+redef class AbstractCompiler
+       # Cache to avoid multiple compilation of NULL values
+       # see FIXME in `MNullableType#compile_extern_helper_functions`
+       private var compiled_null_types = new Array[MNullableType]
+end
+
+redef class AbstractCompilerVisitor
+       # Create a `RuntimeVariable` for this C variable originating from C user code
+       private fun var_from_c(name: String, mtype: MType): RuntimeVariable
+       do
+               if mtype.is_cprimitive then
+                       return new RuntimeVariable(name, mtype, mtype)
+               else
+                       return new RuntimeVariable("{name}->value", mtype, mtype)
+               end
+       end
+
+       # Return a `RuntimeVarible` to C user code
+       private fun ret_to_c(src: RuntimeVariable, mtype: MType)
+       do
+               if mtype.is_cprimitive then
+                       add("return {src};")
+               else
+                       add("struct nitni_instance* ret_for_c;")
+                       add("ret_for_c = nit_alloc(sizeof(struct nitni_instance));")
+                       add("ret_for_c->value = {src};")
+                       add("return ret_for_c;")
+               end
+       end
+end
+
+redef class MType
+       private fun compile_extern_type(v: AbstractCompilerVisitor, ccu: CCompilationUnit)
+       do
+               assert not is_cprimitive
+
+               # define friendly type
+               ccu.header_c_types.add("#ifndef NIT_TYPE_{cname}\n")
+               ccu.header_c_types.add("#define NIT_TYPE_{cname} 1\n")
+               ccu.header_c_types.add("typedef struct nitni_instance *{cname};\n")
+               ccu.header_c_types.add("#endif\n")
+       end
+end