nitg: add option --hardening

[nit.git] / src / global_compiler.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2012 Jean Privat <jean@pryen.org>
#
# 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.

# Global compilation of a Nit program
#
# Techniques used are:
#   * heterogeneous generics
#   * customization
#   * switch dispatch
#   * inlining
module global_compiler

import literal
import typing
import auto_super_init
import rapid_type_analysis

redef class ToolContext
        # --output
        var opt_output: OptionString = new OptionString("Output file", "-o", "--output")

        # --no-cc
        var opt_no_cc: OptionBool = new OptionBool("Do not invoke C compiler", "--no-cc")

        # --hardening
        var opt_hardening: OptionBool = new OptionBool("Generate contracts in the C code against bugs in the compiler", "--hardening")

        redef init
        do
                super
                self.option_context.add_option(self.opt_output, self.opt_no_cc, self.opt_hardening)
        end
end

redef class ModelBuilder
        fun run_global_compiler(mainmodule: MModule, runtime_type_analysis: RapidTypeAnalysis)
        do
                var time0 = get_time
                self.toolcontext.info("*** COMPILING TO C ***", 1)

                var compiler = new GlobalCompiler(mainmodule, runtime_type_analysis, self)
                var v = new GlobalCompilerVisitor(compiler)

                v.add_decl("#include <stdlib.h>")
                v.add_decl("#include <stdio.h>")
                v.add_decl("#include <string.h>")

                # TODO: Better way to activate the GC
                #v.add_decl("#include <gc/gc.h>")
                v.add_decl("#define GC_MALLOC(x) calloc(1, (x))")

                # Declare structure for each live type

                v.add_decl("typedef struct \{int classid;\} val;")
                for t in runtime_type_analysis.live_types do
                        compiler.declare_runtimeclass(v, t)
                end

                v.add_decl("extern int glob_argc;")
                v.add_decl("extern char **glob_argv;")
                v.add_decl("extern val *glob_sys;")

                # Class names (for the class_name and output_class_name methods)

                v.add_decl("extern const char const * class_names[];")
                v.add("const char const * class_names[] = \{")
                for t in runtime_type_analysis.live_types do
                        v.add("\"{t}\", /* {compiler.classid(t)} */")
                end
                v.add("\};")
                compiler.header = v

                # Init instance code (allocate and init-arguments)

                for t in runtime_type_analysis.live_types do
                        if t.ctype != "val*" then continue
                        compiler.generate_init_instance(t)
                end

                # The main function of the C

                v = new GlobalCompilerVisitor(compiler)
                v.add_decl("int glob_argc;")
                v.add_decl("char **glob_argv;")
                v.add_decl("val *glob_sys;")
                v.add_decl("int main(int argc, char** argv) \{")
                v.add("glob_argc = argc; glob_argv = argv;")
                var main_type = mainmodule.sys_type
                if main_type == null then return # Nothing to compile
                var glob_sys = v.init_instance(main_type)
                v.add("glob_sys = {glob_sys};")
                var main_init = mainmodule.try_get_primitive_method("init", main_type)
                if main_init != null then
                        v.send(main_init, [glob_sys])
                end
                var main_method = mainmodule.try_get_primitive_method("main", main_type)
                if main_method != null then
                        v.send(main_method, [glob_sys])
                end
                v.add("\}")

                # Compile until all runtime_functions are visited

                while not compiler.todos.is_empty do
                        var m = compiler.todos.shift
                        self.toolcontext.info("Compile {m.mmethoddef} for {m.recv} ({compiler.seen.length-compiler.todos.length}/{compiler.seen.length})", 3)
                        m.mmethoddef.compile_to_c(compiler, self, m.recv)
                end
                self.toolcontext.info("Total methods to compile to C: {compiler.visitors.length}", 2)

                # Generate the .h and .c files

                var outname = self.toolcontext.opt_output.value
                if outname == null then
                        outname = "{mainmodule.name}.bin"
                end

                var hfilename = ".nit_compile/{mainmodule.name}.1.h"
                var h = new OFStream.open(hfilename)
                for l in compiler.header.decl_lines do
                        h.write l
                        h.write "\n"
                end
                h.close

                var cfiles = new Array[String]

                var file: nullable OFStream = null
                var count = 0

                ".nit_compile".mkdir
                var i = 0
                for vis in compiler.visitors do
                        count += vis.lines.length
                        if file == null or count > 10000 then
                                i += 1
                                if file != null then file.close
                                var cfilename = ".nit_compile/{mainmodule.name}.{i}.c"
                                cfiles.add(cfilename)
                                file = new OFStream.open(cfilename)
                                file.write "#include \"{mainmodule.name}.1.h\"\n"
                                count = vis.lines.length
                        end
                        if vis != compiler.header then
                                for l in vis.decl_lines do
                                        file.write l
                                        file.write "\n"
                                end
                        end
                        for l in vis.lines do
                                file.write l
                                file.write "\n"
                        end
                end
                if file != null then file.close

                self.toolcontext.info("Total C source files to compile: {cfiles.length}", 2)

                # Generate the Makefile

                var makename = ".nit_compile/{mainmodule.name}.mk"
                var makefile = new OFStream.open(makename)

                makefile.write("CC = ccache cc\nCFLAGS = -g -O2\nLDFLAGS ?= \nLDLIBS  ?= -lm -lgc\n\n")
                makefile.write("all: {outname}\n\n")

                var ofiles = new Array[String]
                for f in cfiles do
                        var o = f.strip_extension(".c") + ".o"
                        makefile.write("{o}: {f}\n\t$(CC) $(CFLAGS) -I .nit_compile -I ../clib -c -o {o} {f}\n\n")
                        ofiles.add(o)
                end

                makefile.write("{outname}: {ofiles.join(" ")} {compiler.extern_bodies.join(" ")}\n\t$(CC) -Wl,--warn-unresolved-symbols $(CFLAGS) $(LDFLAGS) $(LDLIBS) -I .nit_compile -I ../clib -o {outname} {ofiles.join(" ")} {compiler.extern_bodies.join(" ")}\n\n")
                makefile.close
                self.toolcontext.info("Generated makefile: {makename}", 2)

                var time1 = get_time
                self.toolcontext.info("*** END COMPILING TO C: {time1-time0} ***", 2)

                # Execute the Makefile

                if self.toolcontext.opt_no_cc.value then return

                time0 = time1
                self.toolcontext.info("*** COMPILING C ***", 1)
                self.toolcontext.info("make -f {makename} -j 4", 2)

                var res
                if self.toolcontext.verbose_level >= 3 then
                        res = sys.system("make -f {makename} -j 4 2>&1")
                else
                        res = sys.system("make -f {makename} -j 4 2>&1 >/dev/null")
                end
                if res != 0 then
                        toolcontext.error(null, "make failed! Error code: {res}.")
                end

                time1 = get_time
                self.toolcontext.info("*** END COMPILING C: {time1-time0} ***", 2)
        end
end

# Singleton that store the knowledge about the compilation process
private class GlobalCompiler
        # The main module of the program
        var mainmodule: MModule

        # The result of the RTA (used to know live types and methods)
        var runtime_type_analysis: RapidTypeAnalysis

        # The modeulbuilder used to know the model and the AST
        var modelbuilder: ModelBuilder

        # Is hardening asked (see --hardening)
        fun hardening: Bool do return self.modelbuilder.toolcontext.opt_hardening.value

        init(mainmodule: MModule, runtime_type_analysis: RapidTypeAnalysis, modelbuilder: ModelBuilder)
        do
                self.mainmodule = mainmodule
                self.runtime_type_analysis = runtime_type_analysis
                self.modelbuilder = modelbuilder
                self.live_primitive_types = new Array[MClassType]
                for t in runtime_type_analysis.live_types do
                        if t.ctype != "val*" then
                                self.live_primitive_types.add(t)
                        end
                end
        end

        # Subset of runtime_type_analysis.live_types that contains only primitive types
        var live_primitive_types: Array[MClassType]

        # runtime_functions that need to be compiled
        private var todos: List[RuntimeFunction] = new List[RuntimeFunction]

        # runtime_functions already seen (todo or done)
        private var seen: HashSet[RuntimeFunction] = new HashSet[RuntimeFunction]
        fun todo(m: RuntimeFunction)
        do
                if seen.has(m) then return
                todos.add(m)
                seen.add(m)
        end

        # Where global declaration are stored (the main .h)
        #
        # FIXME: should not be a vistor but just somewhere to store lines
        # FIXME: should not have a global .h since its does no helps recompilation
        var header: nullable GlobalCompilerVisitor = null

        # The list of all associated visitors
        # Used to generate .c files
        private var visitors: List[GlobalCompilerVisitor] = new List[GlobalCompilerVisitor]

        # List of additional .c files required to compile (native interface)
        var extern_bodies = new ArraySet[String]

        # Return the C symbol associated to a live type runtime
        # REQUIRE: self.runtime_type_analysis.live_types.has(mtype)
        fun classid(mtype: MClassType): String
        do
                if self.classids.has_key(mtype) then
                        return self.classids[mtype]
                end
                print "No classid for {mtype}"
                abort
        end

        # Cache for classid (computed by declare_runtimeclass)
        private var classids: HashMap[MClassType, String] = new HashMap[MClassType, String]

        # Declare C structures and identifiers for a runtime class
        fun declare_runtimeclass(v: GlobalCompilerVisitor, mtype: MClassType)
        do
                assert self.runtime_type_analysis.live_types.has(mtype)
                v.add_decl("/* runtime class {mtype} */")
                var idnum = classids.length
                var idname = "ID_" + mtype.c_name
                self.classids[mtype] = idname
                v.add_decl("#define {idname} {idnum} /* {mtype} */")
                v.add_decl("struct {mtype.c_name} \{")
                v.add_decl("int classid; /* must be {idname} */")
                if mtype.ctype != "val*" then
                        v.add_decl("{mtype.ctype} value;")
                end
                for cd in mtype.collect_mclassdefs(self.mainmodule) do
                        for p in cd.intro_mproperties do
                                if not p isa MAttribute then continue
                                var t = p.intro.static_mtype.as(not null)
                                t = t.anchor_to(self.mainmodule, mtype)
                                v.add_decl("{t.ctype} {p.intro.c_name}; /* {p}: {t} */")
                        end
                end
                v.add_decl("\};")
        end

        # Generate the init-instance of a live type (allocate + init-instance)
        fun generate_init_instance(mtype: MClassType)
        do
                assert self.runtime_type_analysis.live_types.has(mtype)
                assert mtype.ctype == "val*"
                var v = new GlobalCompilerVisitor(self)

                self.header.add_decl("{mtype.ctype} NEW_{mtype.c_name}(void);")
                v.add_decl("/* allocate {mtype} */")
                v.add_decl("{mtype.ctype} NEW_{mtype.c_name}(void) \{")
                var res = v.new_var(mtype)
                v.add("{res} = GC_MALLOC(sizeof(struct {mtype.c_name}));")
                v.add("{res}->classid = {self.classid(mtype)};")

                for cd in mtype.collect_mclassdefs(self.mainmodule)
                do
                        var n = self.modelbuilder.mclassdef2nclassdef[cd]
                        for npropdef in n.n_propdefs do
                                if npropdef isa AAttrPropdef then
                                        npropdef.init_expr(v, res)
                                end
                        end
                end
                v.add("return {res};")
                v.add("\}")
        end

        # look for a needed .h and .c file for a given .nit source-file
        # FIXME: bad API, parameter should be a MModule, not its source-file
        fun add_extern(file: String)
        do
                file = file.strip_extension(".nit")
                var tryfile = file + ".nit.h"
                if tryfile.file_exists then
                        self.header.add_decl("#include \"{"..".join_path(tryfile)}\"")
                end
                tryfile = file + "_nit.h"
                if tryfile.file_exists then
                        self.header.add_decl("#include \"{"..".join_path(tryfile)}\"")
                end
                tryfile = file + ".nit.c"
                if tryfile.file_exists then
                        self.extern_bodies.add(tryfile)
                end
                tryfile = file + "_nit.c"
                if tryfile.file_exists then
                        self.extern_bodies.add(tryfile)
                end
                #(new OFStream.open("{file.basename("")}._nitni.h")).close
        end
end

redef class String
        # Mangle a string to be a unique valid C identifier
        fun to_cmangle: String
        do
                var res = new Buffer
                var underscore = false
                for c in self do
                        if (c >= 'a' and c <= 'z') or (c >='A' and c <= 'Z') then
                                res.add(c)
                                underscore = false
                                continue
                        end
                        if underscore then
                                res.append('_'.ascii.to_s)
                                res.add('d')
                        end
                        if c >= '0' and c <= '9' then
                                res.add(c)
                                underscore = false
                        else if c == '_' then
                                res.add(c)
                                underscore = true
                        else
                                res.add('_')
                                res.append(c.ascii.to_s)
                                res.add('d')
                                underscore = false
                        end
                end
                return res.to_s
        end

        # Escape " \ ' and non printable characters for literal C strings or characters
        fun escape_to_c: String
        do
                var b = new Buffer
                for c in self do
                        if c == '\n' then
                                b.append("\\n")
                        else if c == '\0' then
                                b.append("\\0")
                        else if c == '"' then
                                b.append("\\\"")
                        else if c == '\'' then
                                b.append("\\\'")
                        else if c == '\\' then
                                b.append("\\\\")
                        else if c.ascii < 32 then
                                b.append("\\{c.ascii.to_base(8, false)}")
                        else
                                b.add(c)
                        end
                end
                return b.to_s
        end
end

redef class MType
        # Return the C type associated to a given Nit static type
        fun ctype: String
        do
                return "val*"
        end

        # Return the name of the C structure associated to a Nit live type
        # FIXME: move to GlobalCompiler so we can check that self is a live type
        fun c_name: String is abstract
        private var c_name_cache: nullable String
end

redef class MClassType
        redef fun c_name
        do
                var res = self.c_name_cache
                if res != null then return res
                res = "{mclass.intro_mmodule.name.to_cmangle}__{mclass.name.to_cmangle}"
                self.c_name_cache = res
                return res
        end

        redef fun ctype: String
        do
                if mclass.name == "Int" then
                        return "long"
                else if mclass.name == "Bool" then
                        return "short int"
                else if mclass.name == "Char" then
                        return "char"
                else if mclass.name == "Float" then
                        return "double"
                else if mclass.name == "NativeString" then
                        return "char*"
                else if mclass.name == "NativeArray" then
                        assert self isa MGenericType
                        return "{self.arguments.first.ctype}*"
                else if mclass.kind == extern_kind then
                        return "void*"
                else
                        return "val*"
                end
        end
end

redef class MGenericType
        redef fun c_name
        do
                var res = self.c_name_cache
                if res != null then return res
                res = super
                for t in self.arguments do
                        res = res + t.c_name
                end
                self.c_name_cache = res
                return res
        end
end

redef class MNullableType
        redef fun c_name
        do
                var res = self.c_name_cache
                if res != null then return res
                res = "nullable_{self.mtype.c_name}"
                self.c_name_cache = res
                return res
        end
end

# A C function associated to a Nit method
# Because of customization, a given Nit method can be compiler more that once
private class RuntimeFunction
        # The associated Nit method
        var mmethoddef: MMethodDef

        # The considered reciever
        # (usually is a live type but no strong guarantee)
        var recv: MClassType

        # The mangled c name of the runtime_function
        fun c_name: String
        do
                var res = self.c_name_cache
                if res != null then return res
                if self.mmethoddef.mclassdef.bound_mtype == self.recv then
                        res = self.mmethoddef.c_name
                else
                        res = "{mmethoddef.c_name}__{recv.c_name}"
                end
                self.c_name_cache = res
                return res
        end

        private var c_name_cache: nullable String = null

        redef fun ==(o)
        # used in the compiler worklist
        do
                if not o isa RuntimeFunction then return false
                if self.mmethoddef != o.mmethoddef then return false
                if self.recv != o.recv then return false
                return true
        end

        redef fun hash
        # used in the compiler work-list
        do
                var res = self.mmethoddef.hash + self.recv.hash
                return res
        end

        redef fun to_s
        do
                if self.mmethoddef.mclassdef.bound_mtype == self.recv then
                        return self.mmethoddef.to_s
                else
                        return "{self.mmethoddef}@{self.recv}"
                end
        end

        # Implements a call of the runtime_function
        # May inline the body
        fun call(v: GlobalCompilerVisitor, arguments: Array[RuntimeVariable]): nullable RuntimeVariable
        do
                var ret = self.mmethoddef.msignature.return_mtype
                if self.mmethoddef.mproperty.is_new then
                        ret = arguments.first.mtype
                end
                if ret != null then
                        ret = v.resolve_for(ret, arguments.first)
                end
                if self.mmethoddef.can_inline(v) then
                        var frame = new Frame(v, self.mmethoddef, self.recv, arguments)
                        frame.returnlabel = v.get_name("RET_LABEL")
                        if ret != null then
                                frame.returnvar = v.new_var(ret)
                        end
                        var old_frame = v.frame
                        v.frame = frame
                        v.add("\{ /* Inline {self} ({arguments.join(",")}) */")
                        self.mmethoddef.compile_inside_to_c(v, arguments)
                        v.add("{frame.returnlabel.as(not null)}:(void)0;")
                        v.add("\}")
                        v.frame = old_frame
                        return frame.returnvar
                end
                v.adapt_signature(self.mmethoddef, arguments)
                v.compiler.todo(self)
                if ret == null then
                        v.add("{self.c_name}({arguments.join(",")});")
                        return null
                else
                        var res = v.new_var(ret)
                        v.add("{res} = {self.c_name}({arguments.join(",")});")
                        return res
                end
        end
end

# A runtime variable hold a runtime value in C
# Runtime variables are associated to local variables and intermediate results
private class RuntimeVariable
        # The name of the variable in the C code
        var name: String

        # The static type of the variable (as declard in C)
        var mtype: MType

        # The current casted type of the variable (as known in Nit)
        var mcasttype: MType

        redef fun to_s do return name

        redef fun inspect do return "<{inspect_head} {name}:{mtype}({mcasttype})>"
end

# Visit the AST to generate the C code.
# Because of inlining, a visitor can visit more than one property.
private class GlobalCompilerVisitor
        # The associated compiler
        var compiler: GlobalCompiler

        init(compiler: GlobalCompiler)
        do
                self.compiler = compiler
                compiler.visitors.add(self)
        end

        # Alias for self.compiler.mainmodule.object_type
        fun object_type: MClassType do return self.compiler.mainmodule.object_type

        # Alias for self.compiler.mainmodule.bool_type
        fun bool_type: MClassType do return self.compiler.mainmodule.bool_type

        # Force to get the primitive class named `name' or abort
        fun get_class(name: String): MClass
        do
                return self.compiler.mainmodule.get_primitive_class(name)
        end

        # Force to get the primitive property named `name' in the instance `recv' or abort
        fun get_property(name: String, recv: MType): MMethod
        do
                return self.compiler.mainmodule.force_get_primitive_method(name, recv)
        end

        # The current Frame
        var frame: nullable Frame

        # Anchor a type to the main module and the current receiver
        fun anchor(mtype: MType): MType
        do
                if not mtype.need_anchor then return mtype
                #debug("anchor {mtype} to {self.reciever.as(not null)}:{self.reciever.mtype}")
                return mtype.anchor_to(self.compiler.mainmodule, self.frame.receiver)
        end

        # Add a line in the main part of the generated C
        fun add(s: String)
        do
                self.lines.add(s)
        end

        # Add a line in the
        # (used for local or global declaration)
        fun add_decl(s: String)
        do
                self.decl_lines.add(s)
        end

        private var lines: List[String] = new List[String]
        private var decl_lines: List[String] = new List[String]

        # The current visited AST node
        var current_node: nullable AExpr = null

        # Compile an expression an return its
        fun expr(nexpr: AExpr, mtype: nullable MType): RuntimeVariable
        do
                var old = self.current_node
                self.current_node = nexpr
                var res = nexpr.expr(self).as(not null)
                if mtype != null then
                        mtype = self.anchor(mtype)
                        res = self.autobox(res, mtype)
                end
                self.current_node = old
                return res
        end

        # Unsafely cast a value to a new type
        # ENSURE: return.name == value.name
        fun autoadapt(value: RuntimeVariable, mtype: MType): RuntimeVariable
        do
                mtype = self.anchor(mtype)
                if value.mtype.is_subtype(self.compiler.mainmodule, null, mtype) then
                        return value
                end

                var valmtype = value.mtype
                if valmtype isa MNullableType and valmtype.mtype.is_subtype(self.compiler.mainmodule, null, mtype) then
                        var res = new RuntimeVariable(value.name, value.mtype, valmtype.mtype)
                        return res
                else
                        var res = new RuntimeVariable(value.name, value.mtype, mtype)
                        return res
                end
        end

        # Box or unbox a value to another type iff a C type conversion is needed
        # ENSURE: result.mtype.ctype == mtype.ctype
        fun autobox(value: RuntimeVariable, mtype: MType): RuntimeVariable
        do
                if value.mtype.ctype == mtype.ctype then
                        return value
                else if value.mtype.ctype == "val*" then
                        return self.new_expr("((struct {mtype.c_name}*){value})->value /* autounbox from {value.mtype} to {mtype} */", mtype)
                else if mtype.ctype == "val*" then
                        var valtype = value.mtype.as(MClassType)
                        var res = self.new_var(mtype)
                        if not compiler.runtime_type_analysis.live_types.has(valtype) then
                                self.add("/*no autobox from {value.mtype} to {mtype}: {value.mtype} is not live! */")
                                self.add("printf(\"Dead code executed!\\n\"); exit(1);")
                                return res
                        end
                        self.add("{res} = GC_MALLOC(sizeof(struct {valtype.c_name})); /* autobox from {value.mtype} to {mtype} */")
                        self.add("{res}->classid = {self.compiler.classid(valtype)};")
                        self.add("((struct {valtype.c_name}*){res})->value = {value};")
                        return res
                else
                        # Bad things will append!
                        var res = self.new_var(mtype)
                        self.add("/* {res} left unintialized (cannot convert {value.mtype} to {mtype}) */")
                        self.add("printf(\"Cast error: Cannot cast %s to %s.\\n\", \"{value.mtype}\", \"{mtype}\"); exit(1);")
                        return res
                end
        end

        # Correctly assign a left and a right value
        # Boxing and unboxing is performed if required
        fun assign(left, right: RuntimeVariable)
        do
                right = self.autobox(right, left.mtype)
                self.add("{left} = {right};")
        end


        # Alias for `self.expr(nexpr, self.bool_type)'
        fun expr_bool(nexpr: AExpr): RuntimeVariable
        do
                return expr(nexpr, bool_type)
        end

        # Compile statement
        fun stmt(nexpr: nullable AExpr)
        do
                if nexpr == null then return
                var old = self.current_node
                self.current_node = nexpr
                nexpr.stmt(self)
                self.current_node = old
        end

        # Safely show a debug message on the current node and repeat the message in the C code
        fun debug(message: String)
        do
                var node = self.current_node
                if node == null then
                        print "?: {message}"
                else
                        node.debug(message)
                end
                self.add("/* DEBUG: {message} */")
        end

        # Return a new uninitialized local runtime_variable
        fun new_var(mtype: MType): RuntimeVariable
        do
                if mtype isa MNullType then
                        mtype = self.object_type
                else
                        mtype = self.anchor(mtype)
                end
                var name = self.get_name("var")
                var res = new RuntimeVariable(name, mtype, mtype)
                self.add_decl("{mtype.ctype} {name} /* : {mtype} */;")
                return res
        end

        # Return a new local runtime_variable initialized with the C expression `cexpr'.
        fun new_expr(cexpr: String, mtype: MType): RuntimeVariable
        do
                var res = new_var(mtype)
                self.add("{res} = {cexpr};")
                return res
        end

        # Return the local runtime_variable associated to a Nit local variable
        fun variable(variable: Variable): RuntimeVariable
        do
                if self.variables.has_key(variable) then
                        return self.variables[variable]
                else
                        var name = self.get_name("var_{variable.name}")
                        var mtype = variable.declared_type.as(not null)
                        mtype = self.anchor(mtype)
                        var res = new RuntimeVariable(name, mtype, mtype)
                        self.add_decl("{mtype.ctype} {name} /* var {variable}: {mtype} */;")
                        self.variables[variable] = res
                        return res
                end
        end

        private var variables: HashMap[Variable, RuntimeVariable] = new HashMap[Variable, RuntimeVariable]

        # Return a new name based on `s' and unique in the visitor
        fun get_name(s: String): String
        do
                if not self.names.has(s) then
                        self.names.add(s)
                        return s
                end
                var i = self.last + 1
                loop
                        var s2 = s + i.to_s
                        if not self.names.has(s2) then
                                self.last = i
                                self.names.add(s2)
                                return s2
                        end
                        i = i + 1
                end
        end

        private var last: Int = 0

        private var names: HashSet[String] = new HashSet[String]

        # Generate a return with the value `s'
        fun ret(s: RuntimeVariable)
        do
                self.assign(self.frame.returnvar.as(not null), s)
                self.add("goto {self.frame.returnlabel.as(not null)};")
        end

        # The runtime types that are acceptable for a given receiver.
        fun collect_types(recv: RuntimeVariable): Array[MClassType]
        do
                var mtype = recv.mcasttype
                var cache = self.collect_types_cache
                if cache.has_key(mtype) then
                        return cache[mtype]
                end
                var types = new Array[MClassType]
                var mainmodule = self.compiler.mainmodule
                for t in self.compiler.runtime_type_analysis.live_types do
                        if not t.is_subtype(mainmodule, null, mtype) then continue
                        types.add(t)
                end
                cache[mtype] = types
                return types
        end

        private var collect_types_cache: HashMap[MType, Array[MClassType]] = new HashMap[MType, Array[MClassType]]

        fun resolve_for(mtype: MType, recv: RuntimeVariable): MType
        do
                if not mtype.need_anchor then return mtype
                #debug("resolve for {mtype} to {recv}:{recv.mcasttype}(declared as {recv.mtype}) (in {self.reciever.to_s}:{self.reciever.mtype})")
                var res = mtype.resolve_for(recv.mcasttype, self.frame.receiver, self.compiler.mainmodule, true)
                return res
        end

        # Generate a polymorphic send for the method `m' and the arguments `args'
        fun send(m: MMethod, args: Array[RuntimeVariable]): nullable RuntimeVariable
        do
                var types = self.collect_types(args.first)

                var res: nullable RuntimeVariable
                var ret = m.intro.msignature.return_mtype
                if m.is_new then
                        ret = args.first.mtype
                        res = self.new_var(ret)
                else if ret == null then
                        res = null
                else
                        ret = self.resolve_for(ret, args.first)
                        res = self.new_var(ret)
                end

                if types.is_empty then
                        self.add("/*BUG: no live types for {args.first.mtype} . {m}*/")
                        return res
                end
                self.add("/* send {m} on {args.first}: {args.first.mcasttype} (declared {args.first.mtype}) */")
                if args.first.mtype.ctype != "val*" then
                        var propdefs = m.lookup_definitions(self.compiler.mainmodule, args.first.mtype)
                        if propdefs.length == 0 then
                                self.add("/* skip {args.first.mcasttype}, no method {m} */")
                                return res
                        end
                        assert propdefs.length == 1
                        var propdef = propdefs.first
                        var res2 = self.call(propdef, args.first.mtype.as(MClassType), args)
                        if res != null then self.assign(res, res2.as(not null))
                        return res
                end
                if args.first.mcasttype isa MNullableType then
                        self.add("if ({args.first} == NULL) \{ /* Special null case */")
                        if m.name == "==" then
                                assert res != null
                                if args[1].mcasttype.ctype == "val*" then
                                        self.add("{res} = ({args[1]} == NULL);")
                                else
                                        self.add("{res} = 0; /* {args[1]}: {args[1].mcasttype}  cannot be null */")
                                end
                        else if m.name == "!=" then
                                assert res != null
                                if args[1].mcasttype.ctype == "val*" then
                                        self.add("{res} = ({args[1]} != NULL);")
                                else
                                        self.add("{res} = 1; /* {args[1]}: {args[1].mcasttype} cannot be null */")
                                end
                        else
                                self.add_abort("Reciever is null")
                        end
                        self.add "\} else"
                end
                self.add("switch({args.first}->classid) \{")
                var last = types.last
                var defaultpropdef: nullable MMethodDef = null
                for t in types do
                        var propdefs = m.lookup_definitions(self.compiler.mainmodule, t)
                        if propdefs.length == 0 then
                                self.add("/* skip {t}, no method {m} */")
                                continue
                        end
                        var propdef = propdefs.first
                        if propdef.mclassdef.mclass.name == "Object" and t.ctype == "val*" then
                                defaultpropdef = propdef
                                continue
                        end
                        if not self.compiler.hardening and t == last and defaultpropdef == null then
                                self.add("default: /* test {t} */")
                        else
                                self.add("case {self.compiler.classid(t)}: /* test {t} */")
                        end
                        var res2 = self.call(propdef, t, args)
                        if res != null then self.assign(res, res2.as(not null))
                        self.add "break;"
                end
                if defaultpropdef != null then
                        self.add("default: /* default is Object */")
                        var res2 = self.call(defaultpropdef, defaultpropdef.mclassdef.bound_mtype, args)
                        if res != null then self.assign(res, res2.as(not null))
                else if self.compiler.hardening then
                        self.add("default: /* bug */")
                        self.bugtype(args.first)
                end
                self.add("\}")
                return res
        end

        fun check_valid_reciever(recvtype: MClassType)
        do
                if self.compiler.runtime_type_analysis.live_types.has(recvtype) or recvtype.mclass.name == "Object" then return
                print "{recvtype} is not a live type"
                abort
        end

        fun call(m: MMethodDef, recvtype: MClassType, args: Array[RuntimeVariable]): nullable RuntimeVariable
        do
                check_valid_reciever(recvtype)
                #debug("call {m} on {recvtype} on {args.first}:{args.first.mtype}")
                if m.mclassdef.mclass.name == "Object" and recvtype.ctype == "val*" then
                        recvtype = m.mclassdef.bound_mtype
                end
                var recv = self.autobox(args.first, recvtype)
                recv = self.autoadapt(recv, recvtype)

                var vararg_rank = m.msignature.vararg_rank
                if vararg_rank >= 0 then
                        assert args.length >= m.msignature.arity + 1 # because of self
                        var rawargs = args
                        args = new Array[RuntimeVariable]

                        args.add(rawargs.first) # recv

                        for i in [0..vararg_rank[ do
                                args.add(rawargs[i+1])
                        end

                        var vararg_lastrank = vararg_rank + rawargs.length-1-m.msignature.arity
                        var vararg = new Array[RuntimeVariable]
                        for i in [vararg_rank..vararg_lastrank] do
                                vararg.add(rawargs[i+1])
                        end
                        # FIXME: its it to late to determine the vararg type, this should have been done during a previous analysis
                        var elttype = m.msignature.parameter_mtypes[vararg_rank]
                        elttype = self.resolve_for(elttype, recv)
                        args.add(self.array_instance(vararg, elttype))

                        for i in [vararg_lastrank+1..rawargs.length-1[ do
                                args.add(rawargs[i+1])
                        end
                else
                        args = args.to_a
                end
                assert args.length == m.msignature.arity + 1 # because of self

                args.first = recv
                var rm = new RuntimeFunction(m, recvtype)
                return rm.call(self, args)
        end

        fun adapt_signature(m: MMethodDef, args: Array[RuntimeVariable])
        do
                var recv = args.first
                for i in [0..m.msignature.arity[ do
                        var t = m.msignature.parameter_mtypes[i]
                        if i == m.msignature.vararg_rank then
                                t = args[i+1].mtype
                        end
                        t = self.resolve_for(t, recv)
                        args[i+1] = self.autobox(args[i+1], t)
                end
        end

        fun bugtype(recv: RuntimeVariable)
        do
                if recv.mtype.ctype != "val*" then return
                self.add("fprintf(stderr, \"BTD BUG: Dynamic type is %s, static type is %s\\n\", class_names[{recv}->classid], \"{recv.mcasttype}\");")
        end

        # Generate a polymorphic attribute read
        fun read_attribute(a: MAttribute, recv: RuntimeVariable): RuntimeVariable
        do
                var types = self.collect_types(recv)

                var ret = a.intro.static_mtype.as(not null)
                ret = self.resolve_for(ret, recv)
                var res = self.new_var(ret)

                if types.is_empty then
                        self.add("/*BUG: no live types for {recv.mtype} . {a}*/")
                        return res
                end
                self.add("/* read {a} on {recv.mcasttype} */")
                self.add("switch({recv}->classid) \{")
                var last = types.last
                for t in types do
                        if not self.compiler.hardening and t == last then
                                self.add("default: /*{self.compiler.classid(t)}*/")
                        else
                                self.add("case {self.compiler.classid(t)}:")
                        end
                        var recv2 = self.autoadapt(recv, t)
                        var ta = a.intro.static_mtype.as(not null)
                        ta = self.resolve_for(ta, recv2)
                        var res2 = self.new_expr("((struct {t.c_name}*){recv})->{a.intro.c_name}", ta)
                        if not ta isa MNullableType then
                                if ta.ctype == "val*" then
                                        self.add("if ({res2} == NULL) \{")
                                        self.add_abort("Uninitialized attribute {a.name}")
                                        self.add("\}")
                                else
                                        self.add("/*NOTYET isset on primitive attributes*/")
                                end
                        end
                        self.assign(res, res2)
                        self.add("break;")
                end
                if self.compiler.hardening then
                        self.add("default: /* Bug */")
                        self.bugtype(recv)
                end
                self.add("\}")

                return res
        end

        # Generate a polymorphic attribute write
        fun write_attribute(a: MAttribute, recv: RuntimeVariable, value: RuntimeVariable)
        do
                var types = self.collect_types(recv)

                if types.is_empty then
                        self.add("/*BUG: no live types for {recv.mtype} . {a}*/")
                        return
                end
                self.add("/* write {a} on {recv.mcasttype} */")
                self.add("switch({recv}->classid) \{")
                var last = types.last
                for t in types do
                        if not self.compiler.hardening and t == last then
                                self.add("default: /*{self.compiler.classid(t)}*/")
                        else
                                self.add("case {self.compiler.classid(t)}:")
                        end
                        var recv2 = self.autoadapt(recv, t)
                        var ta = a.intro.static_mtype.as(not null)
                        ta = self.resolve_for(ta, recv2)
                        self.add("((struct {t.c_name}*){recv})->{a.intro.c_name} = {self.autobox(value, ta)};")
                        self.add("break;")
                end
                if self.compiler.hardening then
                        self.add("default: /* Bug*/")
                        self.bugtype(recv)
                end
                self.add("\}")
        end

        # Generate a alloc-instance + init-attributes
        fun init_instance(mtype: MClassType): RuntimeVariable
        do
                mtype = self.anchor(mtype).as(MClassType)
                if not self.compiler.runtime_type_analysis.live_types.has(mtype) then
                        debug "problem: {mtype} was detected dead"
                end
                var res = self.new_expr("NEW_{mtype.c_name}()", mtype)
                return res
        end

        # Generate a polymorphic subtype test
        fun type_test(value: RuntimeVariable, mtype: MType): RuntimeVariable
        do
                mtype = self.anchor(mtype)
                var types = self.collect_types(value)

                var res = self.new_var(bool_type)

                self.add("/* isa {mtype} on {value.mcasttype} */")
                if value.mcasttype isa MNullableType then
                        self.add("if ({value} == NULL) \{")
                        if mtype isa MNullableType then
                                self.add("{res} = 1; /* isa {mtype} */")
                        else
                                self.add("{res} = 0; /* not isa {mtype} */")
                        end
                        self.add("\} else ")
                end
                self.add("switch({value}->classid) \{")
                for t in types do
                        if t.is_subtype(self.compiler.mainmodule, null, mtype) then
                                self.add("case {self.compiler.classid(t)}: /* {t} */")
                        end
                end
                self.add("{res} = 1;")
                self.add("break;")
                self.add("default:")
                self.add("{res} = 0;")
                self.add("\}")

                return res
        end

        # Generate a Nit "is" for two runtime_variables
        fun equal_test(value1, value2: RuntimeVariable): RuntimeVariable
        do
                var res = self.new_var(bool_type)
                if value2.mtype.ctype != "val*" and value1.mtype.ctype == "val*" then
                        var tmp = value1
                        value1 = value2
                        value2 = tmp
                end
                if value1.mtype.ctype != "val*" then
                        if value2.mtype.ctype == value1.mtype.ctype then
                                self.add("{res} = {value1} == {value2};")
                        else if value2.mtype.ctype != "val*" then
                                self.add("{res} = 0; /* incompatible types {value1.mtype} vs. {value2.mtype}*/")
                        else
                                var mtype1 = value1.mtype.as(MClassType)
                                self.add("{res} = ({value2} != NULL) && ({value2}->classid == {self.compiler.classid(mtype1)});")
                                self.add("if ({res}) \{")
                                self.add("{res} = ({self.autobox(value2, value1.mtype)} == {value1});")
                                self.add("\}")
                        end
                else
                        var s = new Array[String]
                        for t in self.compiler.live_primitive_types do
                                if not t.is_subtype(self.compiler.mainmodule, null, value1.mcasttype) then continue
                                if not t.is_subtype(self.compiler.mainmodule, null, value2.mcasttype) then continue
                                s.add "({value1}->classid == {self.compiler.classid(t)} && ((struct {t.c_name}*){value1})->value == ((struct {t.c_name}*){value2})->value)"
                        end
                        if s.is_empty then
                                self.add("{res} = {value1} == {value2};")
                        else
                                self.add("{res} = {value1} == {value2} || ({value1} != NULL && {value2} != NULL && {value1}->classid == {value2}->classid && ({s.join(" || ")}));")
                        end
                end
                return res
        end

        # Generate a check-init-instance
        # TODO: is an empty stub currently
        fun check_init_instance(recv: RuntimeVariable)
        do
        end

        # Generate an integer value
        fun int_instance(value: Int): RuntimeVariable
        do
                var res = self.new_var(self.get_class("Int").mclass_type)
                self.add("{res} = {value};")
                return res
        end

        # Generate an array value
        fun array_instance(array: Array[RuntimeVariable], elttype: MType): RuntimeVariable
        do
                elttype = self.anchor(elttype)
                var res = self.init_instance(self.get_class("Array").get_mtype([elttype]))
                self.add("\{ /* {res} = array_instance Array[{elttype}] */")
                var nat = self.new_var(self.get_class("NativeArray").get_mtype([elttype]))
                self.add("{nat} = GC_MALLOC({array.length} * sizeof({elttype.ctype}));")
                for i in [0..array.length[ do
                        var r = self.autobox(array[i], elttype)
                        self.add("{nat}[{i}] = {r};")
                end
                var length = self.int_instance(array.length)
                self.send(self.get_property("with_native", res.mtype), [res, nat, length])
                self.check_init_instance(res)
                self.add("\}")
                return res
        end

        # Generate a string value
        fun string_instance(string: String): RuntimeVariable
        do
                var nat = self.new_var(self.get_class("NativeString").mclass_type)
                self.add("{nat} = \"{string.escape_to_c}\";")
                var res = self.init_instance(self.get_class("String").mclass_type)
                var length = self.int_instance(string.length)
                self.send(self.get_property("with_native", res.mtype), [res, nat, length])
                self.check_init_instance(res)
                return res
        end

        # Generate generic abort
        # used by aborts, asserts, casts, etc.
        fun add_abort(message: String)
        do
                if self.current_node != null and self.current_node.location.file != null then
                        self.add("fprintf(stderr, \"%s (%s:%d)\\n\", \"{message.escape_to_c}\", \"{self.current_node.location.file.filename.escape_to_c}\", {current_node.location.line_start});")
                else
                        self.add("fprintf(stderr, \"%s\\n\", \"{message.escape_to_c}\");")
                end
                self.add("exit(1);")
        end
end

# A frame correspond to a visited property in a GlobalCompilerVisitor
private class Frame
        # The associated visitor

        var visitor: GlobalCompilerVisitor

        # The executed property.
        # A Method in case of a call, an attribute in case of a default initialization.
        var mpropdef: MPropDef

        # The static type of the receiver
        var receiver: MClassType

        # Arguments of the method (the first is the receiver)
        var arguments: Array[RuntimeVariable]

        # The runtime_variable associated to the return (in a function)
        var returnvar: nullable RuntimeVariable = null

        # The label at the end of the property
        var returnlabel: nullable String = null
end

redef class MPropDef
        private var c_name_cache: nullable String

        # The mangled name associated to the property
        fun c_name: String
        do
                var res = self.c_name_cache
                if res != null then return res
                res = "{self.mclassdef.mmodule.name.to_cmangle}__{self.mclassdef.mclass.name.to_cmangle}__{self.mproperty.name.to_cmangle}"
                self.c_name_cache = res
                return res
        end
end

redef class MMethodDef
        # Can the body be inlined?
        private fun can_inline(v: GlobalCompilerVisitor): Bool
        do
                var modelbuilder = v.compiler.modelbuilder
                if modelbuilder.mpropdef2npropdef.has_key(self) then
                        var npropdef = modelbuilder.mpropdef2npropdef[self]
                        return npropdef.can_inline
                else if self.mproperty.name == "init" then
                        # Automatic free init is always inlined since it is empty or contains only attribtes assigments
                        return true
                else
                        abort
                end
        end

        # Inline the body in another visitor
        private fun compile_inside_to_c(v: GlobalCompilerVisitor, arguments: Array[RuntimeVariable]): nullable RuntimeVariable
        do
                var modelbuilder = v.compiler.modelbuilder
                if modelbuilder.mpropdef2npropdef.has_key(self) then
                        var npropdef = modelbuilder.mpropdef2npropdef[self]
                        npropdef.compile_to_c(v, self, arguments)
                else if self.mproperty.name == "init" then
                        var nclassdef = modelbuilder.mclassdef2nclassdef[self.mclassdef]
                        nclassdef.compile_to_c(v, self, arguments)
                else
                        abort
                end
                return null
        end

        # Compile the body in a new visitor
        private fun compile_to_c(compiler: GlobalCompiler, modelbuilder: ModelBuilder, recv: MClassType)
        do
                if not recv.is_subtype(compiler.mainmodule, null, self.mclassdef.bound_mtype) then
                        print("problem: why do we compile {self} for {recv}?")
                        abort
                end

                var v = new GlobalCompilerVisitor(compiler)
                var selfvar = new RuntimeVariable("self", recv, recv)
                var arguments = new Array[RuntimeVariable]
                var frame = new Frame(v, self, recv, arguments)
                v.frame = frame

                var sig = new Buffer
                var comment = new Buffer
                var ret = self.msignature.return_mtype
                if ret != null then
                        ret = v.resolve_for(ret, selfvar)
                        sig.append("{ret.ctype} ")
                else if self.mproperty.is_new then
                        ret = recv
                        sig.append("{ret.ctype} ")
                else
                        sig.append("void ")
                end
                sig.append(self.c_name)
                if recv != self.mclassdef.bound_mtype then
                        sig.append("__{recv.c_name}")
                end
                sig.append("({recv.ctype} self")
                comment.append("(self: {recv}")
                arguments.add(selfvar)
                for i in [0..self.msignature.arity[ do
                        var mtype = self.msignature.parameter_mtypes[i]
                        if i == self.msignature.vararg_rank then
                                mtype = v.get_class("Array").get_mtype([mtype])
                        end
                        mtype = v.resolve_for(mtype, selfvar)
                        comment.append(", {mtype}")
                        sig.append(", {mtype.ctype} p{i}")
                        var argvar = new RuntimeVariable("p{i}", mtype, mtype)
                        arguments.add(argvar)
                end
                sig.append(")")
                comment.append(")")
                if ret != null then
                        comment.append(": {ret}")
                end
                compiler.header.add_decl("{sig};")

                v.add_decl("/* method {self} for {comment} */")
                v.add_decl("{sig} \{")
                #v.add("printf(\"method {self} for {comment}\\n\");")
                if ret != null then
                        frame.returnvar = v.new_var(ret)
                end
                frame.returnlabel = v.get_name("RET_LABEL")

                if modelbuilder.mpropdef2npropdef.has_key(self) then
                        var npropdef = modelbuilder.mpropdef2npropdef[self]
                        npropdef.compile_to_c(v, self, arguments)
                else if self.mproperty.name == "init" then
                        var nclassdef = modelbuilder.mclassdef2nclassdef[self.mclassdef]
                        nclassdef.compile_to_c(v, self, arguments)
                else
                        abort
                end

                v.add("{frame.returnlabel.as(not null)}:;")
                if ret != null then
                        v.add("return {frame.returnvar.as(not null)};")
                end
                v.add("\}")
        end
end

redef class APropdef
        private fun compile_to_c(v: GlobalCompilerVisitor, mpropdef: MMethodDef, arguments: Array[RuntimeVariable])
        do
                v.add("printf(\"Not implemented {class_name} {mpropdef} at {location.to_s}\\n\");")
                debug("Not yet implemented")
        end

        private fun can_inline: Bool do return true
end

redef class AConcreteMethPropdef
        redef fun compile_to_c(v, mpropdef, arguments)
        do
                for i in [0..mpropdef.msignature.arity[ do
                        var variable = self.n_signature.n_params[i].variable.as(not null)
                        v.assign(v.variable(variable), arguments[i+1])
                end
                # Call the implicit super-init
                var auto_super_inits = self.auto_super_inits
                if auto_super_inits != null then
                        var selfarg = [arguments.first]
                        for auto_super_init in auto_super_inits do
                                if auto_super_init.intro.msignature.arity == 0 then
                                        v.send(auto_super_init, selfarg)
                                else
                                        v.send(auto_super_init, arguments)
                                end
                        end
                end

                v.stmt(self.n_block)
        end

        redef fun can_inline
        do
                if self.auto_super_inits != null then return false
                var nblock = self.n_block
                if nblock == null then return true
                if (mpropdef.mproperty.name == "==" or mpropdef.mproperty.name == "!=") and mpropdef.mclassdef.mclass.name == "Object" then return true
                if nblock isa ABlockExpr and nblock.n_expr.length == 0 then return true
                return false
        end
end

redef class AInternMethPropdef
        redef fun compile_to_c(v, mpropdef, arguments)
        do
                var pname = mpropdef.mproperty.name
                var cname = mpropdef.mclassdef.mclass.name
                var ret = mpropdef.msignature.return_mtype
                if ret != null then
                        ret = v.resolve_for(ret, arguments.first)
                end
                if pname != "==" and pname != "!=" then
                        v.adapt_signature(mpropdef, arguments)
                end
                if cname == "Int" then
                        if pname == "output" then
                                v.add("printf(\"%ld\\n\", {arguments.first});")
                                return
                        else if pname == "object_id" then
                                v.ret(arguments.first)
                                return
                        else if pname == "+" then
                                v.ret(v.new_expr("{arguments[0]} + {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "-" then
                                v.ret(v.new_expr("{arguments[0]} - {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "unary -" then
                                v.ret(v.new_expr("-{arguments[0]}", ret.as(not null)))
                                return
                        else if pname == "succ" then
                                v.ret(v.new_expr("{arguments[0]}+1", ret.as(not null)))
                                return
                        else if pname == "prec" then
                                v.ret(v.new_expr("{arguments[0]}-1", ret.as(not null)))
                                return
                        else if pname == "*" then
                                v.ret(v.new_expr("{arguments[0]} * {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "/" then
                                v.ret(v.new_expr("{arguments[0]} / {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "%" then
                                v.ret(v.new_expr("{arguments[0]} % {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "lshift" then
                                v.ret(v.new_expr("{arguments[0]} << {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "rshift" then
                                v.ret(v.new_expr("{arguments[0]} >> {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "==" then
                                v.ret(v.equal_test(arguments[0], arguments[1]))
                                return
                        else if pname == "!=" then
                                var res = v.equal_test(arguments[0], arguments[1])
                                v.ret(v.new_expr("!{res}", ret.as(not null)))
                                return
                        else if pname == "<" then
                                v.ret(v.new_expr("{arguments[0]} < {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == ">" then
                                v.ret(v.new_expr("{arguments[0]} > {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "<=" then
                                v.ret(v.new_expr("{arguments[0]} <= {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == ">=" then
                                v.ret(v.new_expr("{arguments[0]} >= {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "to_f" then
                                v.ret(v.new_expr("(double){arguments[0]}", ret.as(not null)))
                                return
                        else if pname == "ascii" then
                                v.ret(v.new_expr("{arguments[0]}", ret.as(not null)))
                                return
                        end
                else if cname == "Char" then
                        if pname == "output" then
                                v.add("printf(\"%c\", {arguments.first});")
                                return
                        else if pname == "object_id" then
                                v.ret(arguments.first)
                                return
                        else if pname == "==" then
                                v.ret(v.equal_test(arguments[0], arguments[1]))
                                return
                        else if pname == "!=" then
                                var res = v.equal_test(arguments[0], arguments[1])
                                v.ret(v.new_expr("!{res}", ret.as(not null)))
                                return
                        else if pname == "succ" then
                                v.ret(v.new_expr("{arguments[0]}+1", ret.as(not null)))
                                return
                        else if pname == "prec" then
                                v.ret(v.new_expr("{arguments[0]}-1", ret.as(not null)))
                                return
                        else if pname == "<" then
                                v.ret(v.new_expr("{arguments[0]} < {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == ">" then
                                v.ret(v.new_expr("{arguments[0]} > {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "<=" then
                                v.ret(v.new_expr("{arguments[0]} <= {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == ">=" then
                                v.ret(v.new_expr("{arguments[0]} >= {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "to_i" then
                                v.ret(v.new_expr("{arguments[0]}-'0'", ret.as(not null)))
                                return
                        else if pname == "ascii" then
                                v.ret(v.new_expr("(unsigned char){arguments[0]}", ret.as(not null)))
                                return
                        end
                else if cname == "Bool" then
                        if pname == "output" then
                                v.add("printf({arguments.first}?\"true\\n\":\"false\\n\");")
                                return
                        else if pname == "object_id" then
                                v.ret(arguments.first)
                                return
                        else if pname == "==" then
                                v.ret(v.equal_test(arguments[0], arguments[1]))
                                return
                        else if pname == "!=" then
                                var res = v.equal_test(arguments[0], arguments[1])
                                v.ret(v.new_expr("!{res}", ret.as(not null)))
                                return
                        end
                else if cname == "Float" then
                        if pname == "output" then
                                v.add("printf(\"%f\\n\", {arguments.first});")
                                return
                        else if pname == "object_id" then
                                v.ret(v.new_expr("(double){arguments.first}", ret.as(not null)))
                                return
                        else if pname == "+" then
                                v.ret(v.new_expr("{arguments[0]} + {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "-" then
                                v.ret(v.new_expr("{arguments[0]} - {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "unary -" then
                                v.ret(v.new_expr("-{arguments[0]}", ret.as(not null)))
                                return
                        else if pname == "succ" then
                                v.ret(v.new_expr("{arguments[0]}+1", ret.as(not null)))
                                return
                        else if pname == "prec" then
                                v.ret(v.new_expr("{arguments[0]}-1", ret.as(not null)))
                                return
                        else if pname == "*" then
                                v.ret(v.new_expr("{arguments[0]} * {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "/" then
                                v.ret(v.new_expr("{arguments[0]} / {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "==" then
                                v.ret(v.equal_test(arguments[0], arguments[1]))
                                return
                        else if pname == "!=" then
                                var res = v.equal_test(arguments[0], arguments[1])
                                v.ret(v.new_expr("!{res}", ret.as(not null)))
                                return
                        else if pname == "<" then
                                v.ret(v.new_expr("{arguments[0]} < {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == ">" then
                                v.ret(v.new_expr("{arguments[0]} > {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "<=" then
                                v.ret(v.new_expr("{arguments[0]} <= {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == ">=" then
                                v.ret(v.new_expr("{arguments[0]} >= {arguments[1]}", ret.as(not null)))
                                return
                        else if pname == "to_i" then
                                v.ret(v.new_expr("(long){arguments[0]}", ret.as(not null)))
                                return
                        end
                else if cname == "Char" then
                        if pname == "output" then
                                v.add("printf(\"%c\", {arguments.first});")
                                return
                        else if pname == "object_id" then
                                v.ret(arguments.first)
                                return
                        else if pname == "==" then
                                v.ret(v.equal_test(arguments[0], arguments[1]))
                                return
                        else if pname == "!=" then
                                var res = v.equal_test(arguments[0], arguments[1])
                                v.ret(v.new_expr("!{res}", ret.as(not null)))
                                return
                        else if pname == "ascii" then
                                v.ret(v.new_expr("{arguments[0]}", ret.as(not null)))
                                return
                        end
                else if cname == "NativeString" then
                        if pname == "[]" then
                                v.ret(v.new_expr("{arguments[0]}[{arguments[1]}]", ret.as(not null)))
                                return
                        else if pname == "[]=" then
                                v.add("{arguments[0]}[{arguments[1]}]={arguments[2]};")
                                return
                        else if pname == "copy_to" then
                                v.add("memcpy({arguments[1]}+{arguments[4]},{arguments[0]}+{arguments[3]},{arguments[2]});")
                                return
                        else if pname == "atoi" then
                                v.ret(v.new_expr("atoi({arguments[0]});", ret.as(not null)))
                                return
                        end
                else if cname == "NativeArray" then
                        var elttype = arguments.first.mtype
                        if pname == "[]" then
                                v.ret(v.new_expr("{arguments[0]}[{arguments[1]}]", ret.as(not null)))
                                return
                        else if pname == "[]=" then
                                v.add("{arguments[0]}[{arguments[1]}]={arguments[2]};")
                                return
                        else if pname == "copy_to" then
                                v.add("memcpy({arguments[1]},{arguments[0]},{arguments[2]}*sizeof({elttype.ctype}));")
                                return
                        end
                end
                if pname == "exit" then
                        v.add("exit({arguments[1]});")
                        return
                else if pname == "sys" then
                        v.ret(v.new_expr("glob_sys", ret.as(not null)))
                        return
                else if pname == "calloc_string" then
                        v.ret(v.new_expr("(char*)GC_MALLOC({arguments[1]})", ret.as(not null)))
                        return
                else if pname == "calloc_array" then
                        var elttype = arguments.first.mtype.supertype_to(v.compiler.mainmodule,arguments.first.mtype.as(MClassType),v.get_class("ArrayCapable")).as(MGenericType).arguments.first
                        v.ret(v.new_expr("({elttype.ctype}*)GC_MALLOC({arguments[1]} * sizeof({elttype.ctype}))", ret.as(not null)))
                        return
                else if pname == "object_id" then
                        v.ret(v.new_expr("(long){arguments.first}", ret.as(not null)))
                        return
                else if pname == "is_same_type" then
                        if arguments[0].mtype.ctype == "val*" then
                                v.ret(v.new_expr("{arguments[0]}->classid == {arguments[1]}->classid", ret.as(not null)))
                        else
                                v.ret(v.new_expr("{v.compiler.classid(arguments[0].mtype.as(MClassType))} == {arguments[1]}->classid", ret.as(not null)))
                        end
                        return
                else if pname == "output_class_name" then
                        if arguments[0].mtype.ctype == "val*" then
                                v.add("printf(\"%s\\n\", class_names[{arguments.first}->classid]);")
                        else
                                v.add("printf(\"%s\\n\", class_names[{v.compiler.classid(arguments.first.mtype.as(MClassType))}]);")
                        end
                        return
                else if pname == "native_class_name" then
                        if arguments[0].mtype.ctype == "val*" then
                                v.ret(v.new_expr("(char*)(void*)class_names[{arguments.first}->classid]", ret.as(not null)))
                        else
                                v.ret(v.new_expr("(char*)(void*)class_names[{v.compiler.classid(arguments.first.mtype.as(MClassType))}]", ret.as(not null)))
                        end
                        return
                end
                v.add("printf(\"Not implemented {class_name}:{mpropdef} at {location.to_s}\\n\");")
                debug("Not implemented {mpropdef}")
        end
end

redef class AExternMethPropdef
        redef fun compile_to_c(v, mpropdef, arguments)
        do
                var externname
                var nextern = self.n_extern
                if nextern == null then
                        debug("{mpropdef} need extern name")
                        return
                end
                externname = nextern.text.substring(1, nextern.text.length-2)
                if location.file != null then
                        var file = location.file.filename
                        v.compiler.add_extern(file)
                end
                var res: nullable RuntimeVariable = null
                var ret = mpropdef.msignature.return_mtype
                if ret != null then
                        ret = v.resolve_for(ret, arguments.first)
                        res = v.new_var(ret)
                end

                if res == null then
                        v.add("{externname}({arguments.join(", ")});")
                else
                        v.add("{res} = {externname}({arguments.join(", ")});")
                        v.ret(res)
                end
        end
end

redef class AExternInitPropdef
        redef fun compile_to_c(v, mpropdef, arguments)
        do
                var externname
                var nextern = self.n_extern
                if nextern == null then
                        debug("{mpropdef} need extern name")
                        return
                end
                externname = nextern.text.substring(1, nextern.text.length-2)
                if location.file != null then
                        var file = location.file.filename
                        v.compiler.add_extern(file)
                end
                var ret = arguments.first.mtype
                var res = v.new_var(ret)

                arguments.shift

                v.add("{res} = {externname}({arguments.join(", ")});")
                v.ret(res)
        end
end

redef class AAttrPropdef
        redef fun compile_to_c(v, mpropdef, arguments)
        do
                if arguments.length == 1 then
                        var res = v.read_attribute(self.mpropdef.mproperty, arguments.first)
                        v.assign(v.frame.returnvar.as(not null), res)
                else
                        v.write_attribute(self.mpropdef.mproperty, arguments.first, arguments[1])
                end
        end

        private fun init_expr(v: GlobalCompilerVisitor, recv: RuntimeVariable)
        do
                var nexpr = self.n_expr
                if nexpr != null then
                        var old_frame = v.frame
                        var frame = new Frame(v, self.mpropdef.as(not null), recv.mtype.as(MClassType), [recv])
                        v.frame = frame
                        var value = v.expr(nexpr, self.mpropdef.static_mtype)
                        v.write_attribute(self.mpropdef.mproperty, recv, value)
                        v.frame = old_frame
                end
        end
end

redef class AClassdef
        private fun compile_to_c(v: GlobalCompilerVisitor, mpropdef: MMethodDef, arguments: Array[RuntimeVariable])
        do
                if mpropdef == self.mfree_init then
                        var super_inits = self.super_inits
                        if super_inits != null then
                                assert arguments.length == 1
                                for su in super_inits do
                                        v.send(su, arguments)
                                end
                                return
                        end
                        var recv = arguments.first
                        var i = 1
                        # Collect undefined attributes
                        for npropdef in self.n_propdefs do
                                if npropdef isa AAttrPropdef and npropdef.n_expr == null then
                                        v.write_attribute(npropdef.mpropdef.mproperty, recv, arguments[i])
                                        i += 1
                                end
                        end
                else
                        abort
                end
        end
end

redef class AExpr
        # Try to compile self as an expression
        # Do not call this method directly, use `v.expr' instead
        private fun expr(v: GlobalCompilerVisitor): nullable RuntimeVariable
        do
                debug("Unimplemented expr {class_name}")
                v.add("printf(\"Not implemented {class_name}:{location.to_s}\\n\");")
                var mtype = self.mtype
                if mtype == null then
                        return null
                else
                        var res = v.new_var(mtype)
                        v.add("/* {res} = NOT YET {class_name} */")
                        return res
                end
        end

        # Try to compile self as a statement
        # Do not call this method directly, use `v.stmt' instead
        private fun stmt(v: GlobalCompilerVisitor)
        do
                var res = expr(v)
                if res != null then v.add("{res};")
        end

end

redef class ABlockExpr
        redef fun stmt(v)
        do
                for e in self.n_expr do
                        v.stmt(e)
                end
        end
end

redef class AVardeclExpr
        redef fun stmt(v)
        do
                var variable = self.variable.as(not null)
                var ne = self.n_expr
                if ne != null then
                        var i = v.expr(ne, variable.declared_type)
                        v.assign(v.variable(variable), i)
                end
        end
end

redef class AVarExpr
        redef fun expr(v)
        do
                var res = v.variable(self.variable.as(not null))
                var mtype = self.mtype.as(not null)
                return v.autoadapt(res, mtype)
        end
end

redef class AVarAssignExpr
        redef fun stmt(v)
        do
                var variable = self.variable.as(not null)
                var i = v.expr(self.n_value, variable.declared_type)
                v.assign(v.variable(variable), i)
        end
end

redef class AVarReassignExpr
        redef fun stmt(v)
        do
                var variable = self.variable.as(not null)
                var vari = v.variable(variable)
                var value = v.expr(self.n_value, variable.declared_type)
                var res = v.send(reassign_property.mproperty, [vari, value])
                assert res != null
                v.assign(v.variable(variable), res)
        end
end

redef class ASelfExpr
        redef fun expr(v)
        do
                return v.frame.arguments.first
        end
end

redef class AContinueExpr
        redef fun stmt(v)
        do
                v.add("goto CONTINUE_{self.escapemark.object_id};")
        end
end

redef class ABreakExpr
        redef fun stmt(v)
        do
                v.add("goto BREAK_{self.escapemark.object_id};")
        end
end

redef class AReturnExpr
        redef fun stmt(v)
        do
                var nexpr = self.n_expr
                if nexpr != null then
                        var returnvar = v.frame.returnvar.as(not null)
                        var i = v.expr(nexpr, returnvar.mtype)
                        v.assign(returnvar, i)
                end
                v.add("goto {v.frame.returnlabel.as(not null)};")
        end
end

redef class AAbortExpr
        redef fun stmt(v)
        do
                v.add_abort("Aborted")
        end
end

redef class AIfExpr
        redef fun stmt(v)
        do
                var cond = v.expr_bool(self.n_expr)
                v.add("if ({cond})\{")
                v.stmt(self.n_then)
                v.add("\} else \{")
                v.stmt(self.n_else)
                v.add("\}")
        end
end

redef class AIfexprExpr
        redef fun expr(v)
        do
                var res = v.new_var(self.mtype.as(not null))
                var cond = v.expr_bool(self.n_expr)
                v.add("if ({cond})\{")
                v.assign(res, v.expr(self.n_then, null))
                v.add("\} else \{")
                v.assign(res, v.expr(self.n_else, null))
                v.add("\}")
                return res
        end
end

redef class ADoExpr
        redef fun stmt(v)
        do
                v.stmt(self.n_block)
                var escapemark = self.escapemark
                if escapemark != null then
                        v.add("BREAK_{escapemark.object_id}: (void)0;")
                end
        end
end

redef class AWhileExpr
        redef fun stmt(v)
        do
                v.add("for(;;) \{")
                var cond = v.expr_bool(self.n_expr)
                v.add("if (!{cond}) break;")
                v.stmt(self.n_block)
                v.add("CONTINUE_{escapemark.object_id}: (void)0;")
                v.add("\}")
                v.add("BREAK_{escapemark.object_id}: (void)0;")
        end
end

redef class ALoopExpr
        redef fun stmt(v)
        do
                v.add("for(;;) \{")
                v.stmt(self.n_block)
                v.add("CONTINUE_{escapemark.object_id}: (void)0;")
                v.add("\}")
                v.add("BREAK_{escapemark.object_id}: (void)0;")
        end
end

redef class AForExpr
        redef fun stmt(v)
        do
                var cl = v.expr(self.n_expr, null)
                var it = v.send(v.get_property("iterator", cl.mtype), [cl])
                assert it != null
                v.add("for(;;) \{")
                var ok = v.send(v.get_property("is_ok", it.mtype), [it])
                assert ok != null
                v.add("if(!{ok}) break;")
                var i = v.send(v.get_property("item", it.mtype), [it])
                assert i != null
                v.assign(v.variable(variables.first), i)
                v.stmt(self.n_block)
                v.add("CONTINUE_{escapemark.object_id}: (void)0;")
                v.send(v.get_property("next", it.mtype), [it])
                v.add("\}")
                v.add("BREAK_{escapemark.object_id}: (void)0;")
        end
end

redef class AAssertExpr
        redef fun stmt(v)
        do
                var cond = v.expr_bool(self.n_expr)
                v.add("if (!{cond}) \{")
                v.stmt(self.n_else)
                var nid = self.n_id
                if nid != null then
                        v.add_abort("Assert '{nid.text}' failed")
                else
                        v.add_abort("Assert failed")
                end
                v.add("\}")
        end
end

redef class AOrExpr
        redef fun expr(v)
        do
                var res = v.new_var(self.mtype.as(not null))
                var i1 = v.expr_bool(self.n_expr)
                v.add("if ({i1}) \{")
                v.add("{res} = 1;")
                v.add("\} else \{")
                var i2 = v.expr_bool(self.n_expr2)
                v.add("{res} = {i2};")
                v.add("\}")
                return res
        end
end

redef class AAndExpr
        redef fun expr(v)
        do
                var res = v.new_var(self.mtype.as(not null))
                var i1 = v.expr_bool(self.n_expr)
                v.add("if (!{i1}) \{")
                v.add("{res} = 0;")
                v.add("\} else \{")
                var i2 = v.expr_bool(self.n_expr2)
                v.add("{res} = {i2};")
                v.add("\}")
                return res
        end
end

redef class ANotExpr
        redef fun expr(v)
        do
                var cond = v.expr_bool(self.n_expr)
                return v.new_expr("!{cond}", self.mtype.as(not null))
        end
end

redef class AOrElseExpr
        redef fun expr(v)
        do
                var res = v.new_var(self.mtype.as(not null))
                var i1 = v.expr(self.n_expr, null)
                v.add("if ({i1}!=NULL) \{")
                v.assign(res, i1)
                v.add("\} else \{")
                var i2 = v.expr(self.n_expr2, null)
                v.assign(res, i2)
                v.add("\}")
                return res
        end
end

redef class AEeExpr
        redef fun expr(v)
        do
                var value1 = v.expr(self.n_expr, null)
                var value2 = v.expr(self.n_expr2, null)
                return v.equal_test(value1, value2)
        end
end

redef class AIntExpr
        redef fun expr(v)
        do
                return v.new_expr("{self.n_number.text}", self.mtype.as(not null))
        end
end

redef class AFloatExpr
        redef fun expr(v)
        do
                return v.new_expr("{self.n_float.text}", self.mtype.as(not null))
        end
end

redef class ACharExpr
        redef fun expr(v)
        do
                return v.new_expr("{self.n_char.text}", self.mtype.as(not null))
        end
end

redef class AArrayExpr
        redef fun expr(v)
        do
                var mtype = self.mtype.as(MGenericType).arguments.first
                var array = new Array[RuntimeVariable]
                for nexpr in self.n_exprs.n_exprs do
                        var i = v.expr(nexpr, mtype)
                        array.add(i)
                end
                return v.array_instance(array, mtype)
        end
end

redef class AStringFormExpr
        redef fun expr(v)
        do
                return v.string_instance(self.value.as(not null))
        end
end

redef class ASuperstringExpr
        redef fun expr(v)
        do
                var array = new Array[RuntimeVariable]
                for ne in self.n_exprs do
                        var i = v.expr(ne, null)
                        array.add(i)
                end
                var a = v.array_instance(array, v.object_type)
                var res = v.send(v.get_property("to_s", a.mtype), [a])
                return res
        end
end

redef class ACrangeExpr
        redef fun expr(v)
        do
                var i1 = v.expr(self.n_expr, null)
                var i2 = v.expr(self.n_expr2, null)
                var res = v.init_instance(self.mtype.as(MClassType))
                var it = v.send(v.get_property("init", res.mtype), [res, i1, i2])
                v.check_init_instance(res)
                return res
        end
end

redef class AOrangeExpr
        redef fun expr(v)
        do
                var i1 = v.expr(self.n_expr, null)
                var i2 = v.expr(self.n_expr2, null)
                var res = v.init_instance(self.mtype.as(MClassType))
                var it = v.send(v.get_property("without_last", res.mtype), [res, i1, i2])
                v.check_init_instance(res)
                return res
        end
end

redef class ATrueExpr
        redef fun expr(v)
        do
                return v.new_expr("1", self.mtype.as(not null))
        end
end

redef class AFalseExpr
        redef fun expr(v)
        do
                return v.new_expr("0", self.mtype.as(not null))
        end
end

redef class ANullExpr
        redef fun expr(v)
        do
                var res = v.new_expr("NULL", self.mtype.as(not null))
                return res
        end
end

redef class AIsaExpr
        redef fun expr(v)
        do
                var i = v.expr(self.n_expr, null)
                return v.type_test(i, self.cast_type.as(not null))
        end
end

redef class AAsCastExpr
        redef fun expr(v)
        do
                var i = v.expr(self.n_expr, null)
                var cond = v.type_test(i, self.mtype.as(not null))
                v.add("if (!{cond}) \{")
                v.add_abort("Cast failed")
                v.add("\}")
                return i
        end
end

redef class AAsNotnullExpr
        redef fun expr(v)
        do
                var i = v.expr(self.n_expr, null)
                v.add("if ({i} == NULL) \{")
                v.add_abort("Cast failed")
                v.add("\}")
                return i
        end
end

redef class AParExpr
        redef fun expr(v)
        do
                return v.expr(self.n_expr, null)
        end
end

redef class AOnceExpr
        redef fun expr(v)
        do
                var mtype = self.mtype.as(not null)
                var name = v.get_name("varonce")
                var guard = v.get_name(name + "_guard")
                v.add_decl("static {mtype.ctype} {name};")
                v.add_decl("static int {guard};")
                var res = v.new_var(mtype)
                v.add("if ({guard}) \{")
                v.add("{res} = {name};")
                v.add("\} else \{")
                var i = v.expr(self.n_expr, mtype)
                v.add("{res} = {i};")
                v.add("{name} = {res};")
                v.add("{guard} = 1;")
                v.add("\}")
                return res
        end
end

redef class ASendExpr
        redef fun expr(v)
        do
                var recv = v.expr(self.n_expr, null)
                var args = [recv]
                for a in compute_raw_arguments do
                        args.add(v.expr(a, null))
                end
                var mproperty = self.mproperty.as(not null)
                return v.send(mproperty, args)
        end
end

redef class ASendReassignFormExpr
        redef fun stmt(v)
        do
                var recv = v.expr(self.n_expr, null)
                var args = [recv]
                for a in compute_raw_arguments do
                        args.add(v.expr(a, null))
                end
                var value = v.expr(self.n_value, null)

                var mproperty = self.mproperty.as(not null)
                var left = v.send(mproperty, args)
                assert left != null

                var res = v.send(reassign_property.mproperty, [left, value])
                assert res != null

                args.add(res)
                v.send(self.write_mproperty.as(not null), args)
        end
end

redef class ASuperExpr
        redef fun expr(v)
        do
                var recv = v.frame.arguments.first
                var args = [recv]
                for a in self.n_args.n_exprs do
                        args.add(v.expr(a, null))
                end
                if args.length == 1 then
                        args = v.frame.arguments
                end

                var mproperty = self.mproperty
                if mproperty != null then
                        if mproperty.intro.msignature.arity == 0 then
                                args = [recv]
                        end
                        # Super init call
                        var res = v.send(mproperty, args)
                        return res
                end

                # stantard call-next-method
                var mpropdef = v.frame.mpropdef
                # FIXME: we do not want an ugly static call!
                var mpropdefs = mpropdef.mproperty.lookup_super_definitions(mpropdef.mclassdef.mmodule, mpropdef.mclassdef.bound_mtype)
                if mpropdefs.length != 1 then
                        debug("MPRODFEFS for super {mpropdef} for {recv}: {mpropdefs.join(", ")}")
                end
                mpropdef = mpropdefs.first
                assert mpropdef isa MMethodDef
                var res = v.call(mpropdef, recv.mtype.as(MClassType), args)
                return res
        end
end

redef class ANewExpr
        redef fun expr(v)
        do
                var mproperty = self.mproperty.as(not null)
                var mtype = self.mtype.as(MClassType)
                var recv
                var ctype = mtype.ctype
                if ctype == "val*" then
                        recv = v.init_instance(mtype)
                else if ctype == "void*" then
                        recv = v.new_expr("NULL/*special!*/", mtype)
                else
                        debug("cannot new {mtype}")
                        abort
                end
                var args = [recv]
                for a in self.n_args.n_exprs do
                        args.add(v.expr(a, null))
                end
                var res2 = v.send(mproperty, args)
                if res2 != null then
                        #self.debug("got {res2} from {mproperty}. drop {recv}")
                        return res2
                end
                v.check_init_instance(recv)
                return recv
        end
end

redef class AAttrExpr
        redef fun expr(v)
        do
                var recv = v.expr(self.n_expr, null)
                var mproperty = self.mproperty.as(not null)
                return v.read_attribute(mproperty, recv)
        end
end

redef class AAttrAssignExpr
        redef fun stmt(v)
        do
                var recv = v.expr(self.n_expr, null)
                var i = v.expr(self.n_value, null)
                var mproperty = self.mproperty.as(not null)
                v.write_attribute(mproperty, recv, i)
        end
end

redef class AAttrReassignExpr
        redef fun stmt(v)
        do
                var recv = v.expr(self.n_expr, null)
                var value = v.expr(self.n_value, null)
                var mproperty = self.mproperty.as(not null)
                var attr = v.read_attribute(mproperty, recv)
                var res = v.send(reassign_property.mproperty, [attr, value])
                assert res != null
                v.write_attribute(mproperty, recv, res)
        end
end

redef class AIssetAttrExpr
end

redef class ADebugTypeExpr
        redef fun stmt(v)
        do
                # do nothing
        end
end