AdaGenerator.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
    OpenGEODE - A tiny SDL Editor for TASTE

    This module generates Ada code from SDL process models.
    The Ada code is compliant with the TASTE interfaces, and is
    using the ASN.1 "Space-Certified" compiler for data type definition.
    (See TASTE documentation for more information)

    The design is flexible and can be used as basis for other backends.

    Entry point:
    The AST of the model that is parsed is described in ogAST.py

    A Visitor Pattern using Python's "singledispatch" mechanism is used
    to go through the AST and generate code for each SDL construct.

    There is a single function called "generate", decorated with the
    singledispatch mechanism, that needs to be called to generate the code
    of any AST element.

    The generate function returns two values: "code" and "local_decl",
    containing a set of statements and a set of local variables
    (that can be later placed anywhere in the code).

    Expressions (all classes derived from ogAST.Expression) are generated
    using the "expression" visitor (singledispatch set of function).

    Expressions return three values: "code", "ada_string" and "local_decl".
    The "ada_string" value is the usable string that corresponds
    to the result of the expression evaluation.

    For example, take the SDL statement "OUTPUT hello(a+5)"

    This results (in TASTE terminology) in calling the required interface
    called "hello" and passing a parameter of an ASN.1 type (say MyInteger).
    The parameter is always passed by reference.

    It is therefore necessary to build a temporary variable to hold the result
    of the "a+5" expression.

    In this example, the "generate" function will return:
    local_decl = ["tmp01 : MyInteger;"]
    (The template backend can then place it wherever appropriate)

    and code = ["tmp01 := a + 5;", "hello(tmp01);"]
    (The template will then do a '\n'.join(code) - and add indents, etc.)

    To know about "tmp01" and generate the code "hello(tmp01);",
    the function will recursively call "generate" and
    pass a+5 as parameter. The call will return the tuple:

    local_decl = ["tmp01 : MyInteger;"]
    code = ["tmp01 := a + 5;"]
    ada_string = "tmp01"

    This design allows to have any level of complexity in the embedded
    expression in a way that is easy to handle (adding constructs with
    this pattern is straightforward, once the generate function for each AST
    entry is properly implemented).

    Copyright (c) 2012-2020 European Space Agency

    Designed and implemented by Maxime Perrotin

    Contact: maxime.perrotin@esa.int
"""


import logging
import traceback
import os
import stat
from itertools import chain, product
from functools import singledispatch

from . import ogAST, Helper

LOG = logging.getLogger(__name__)

__all__ = ['generate']


PROCESS_NAME = ""

# reference to the ASN.1 Data view and to the visible variables (in scope)
TYPES = None

# look-up table to find the module name containing a type
MAPPING_SORT_MODULE = dict()

VARIABLES = {}
LOCAL_VAR = {}
# List of output signals and procedures
OUT_SIGNALS = []
PROCEDURES = []

# Specify that the target is a shared library
SHARED_LIB = False

#SEPARATOR = u'\u00dc'
# Avoid Unicode characters, they cause occasional annoying issues
SEPARATOR = "_0_"
LPREFIX = 'ctxt'
ASN1SCC = 'asn1Scc'


def is_numeric(string):
    ''' Return true if value is a number '''
    try:
        float(string)
    except ValueError:
        return False
    return True


def external_ri_list(process):
    ''' Helper function: create a list of RI with proper signature
    Used for the formal parameters of generic packages when using process type
    '''
    result = []
    #print process.fpar
    for signal in process.output_signals:
        param_name = signal.get('param_name') or f'{signal["name"]}_param'
        param_spec = ''
        if 'type' in signal:
            typename = type_name(signal['type'])
            param_spec = f'({param_name}: in out {typename})'
        result.append(f"procedure RI{SEPARATOR}{signal['name']}{param_spec}")
    for proc in (proc for proc in process.procedures if proc.external):
        ri_header = f'procedure RI{SEPARATOR}{proc.inputString}'
        params = []
        params_spec = ''
        for param in proc.fpar:
            typename = type_name(param['type'])
            if param['direction'] == 'in':
                direct = 'in out'
            else:
                direct = 'out'
            params.append(f'{param["name"]} : {direct} {typename}')
        if params:
            params_spec = u"({})".format("; ".join(params))
            ri_header += params_spec
        result.append(ri_header)

    for timer in process.timers:
        result.append(
                f"procedure Set_{timer} (Val : in out {ASN1SCC}T_Uint32)")
        result.append(f"procedure Reset_{timer}")
    return result


@singledispatch
def generate(*args, **kwargs):
    ''' Generate the code for an item of the AST '''
    raise TypeError('Incorrect, unsupported or missing data in model AST')
    return [], []


# Processing of the AST
@generate.register(ogAST.Process)
def _process(process, simu=False, instance=False, taste=False, **kwargs):
    ''' Generate the code for a complete process (AST Top level)
        use instance=True to generate the code for a process type instance
        rather than the process type itself.
    '''
    # support generation of code of a process type
    if not instance:
        process_name = process.instance_of_name or process.processName
        generic = process.instance_of_name  #  shortcut
        process_instance = process
        process = process.instance_of_ref or process
    else:
        process_name = process.processName
        generic = False
        process_instance = process

    global PROCESS_NAME
    PROCESS_NAME = process_name

    if process_instance is not process:
        # Generate an instance of the process type, too.
        # First copy the list of timers to the instance (otherwise the
        # instance would miss some PIs and RIs to set the actual timers)
        process_instance.timers = process.timers
        generate(process_instance, simu, instance=True, taste=taste)

    global TYPES
    TYPES = process.dataview
    del OUT_SIGNALS[:]
    del PROCEDURES[:]
    OUT_SIGNALS.extend(process.output_signals)
    PROCEDURES.extend(process.procedures)
    global SHARED_LIB
    global LPREFIX
    if simu:
        SHARED_LIB = True
        LPREFIX = f'{process_name}_ctxt'

    for each in PROCEDURES:
        process.random_generator.update(each.random_generator)

    # taste-properties module-specific flag for the Ada backend:
    # import the state data from an external module
    stop_condition = kwargs["ppty_check"] if "ppty_check" in kwargs else ""

    # When building a shared library (with simu=True), generate a "mini-cv"
    # for aadl2glueC to create the code interfacing with asn1scc
    minicv = ['-- Automatically generated by OpenGEODE - do NOT modify!']
    def aadl_template(sp_name, io_param, pi_or_ri):
        ''' AADL mini-cv code in case of shared library
            sp_name  : name of the PI or RI
            io_param : list of (param_name, type_name, direction)
            pi_or_ri : string "PI" or "RI" depending on the direction
            return a string
        '''
        res = []
        if not io_param:
            LOG.info('Parameterless interface "{}" will not appear in the'
                     ' AADL file but will be handled directly by the GUI'
                     .format(sp_name))
            return ''
        # In case of shared library, generate the AADL "mini-cv" code
        res.append('SUBPROGRAM {}'.format(sp_name))
        if io_param:
            res.append('FEATURES')
            for param_name, sort, direction in io_param:
                res.append('    {pname}: {io} PARAMETER DataView::{sort} '
                          '{{encoding=>Native;}};'.format(pname=param_name,
                                                          sort=sort,
                                                          io=direction))
        res.append('END {};\n'.format(sp_name))
        res.append('SUBPROGRAM IMPLEMENTATION {}.GUI_{}'
                      .format(sp_name, pi_or_ri))
        res.append('PROPERTIES')
        res.append('    FV_Name => "{}";'.format(process_name))
        res.append('    Source_Language => GUI_{};'.format(pi_or_ri))
        res.append('END {}.GUI_{};\n'.format(sp_name, pi_or_ri))
        return '\n'.join(res)

    # bash script to simulate the system (TEMPORARY)

    # go up to the root of the AST to get the list of ASN.1 files
    parent = process.parent
    while hasattr(parent, 'parent') and parent.parent:
        parent = parent.parent
    if isinstance(parent, ogAST.System):
        parent = parent.ast
    asn1_filenames = (f"{' '.join(parent.asn1_filenames)} "
                      f"{process_name.lower()}_datamodel.asn")
    asn1_uniq = ' '.join(each for each in parent.asn1_filenames
                         if not each.endswith('dataview-uniq.asn'))
    asn1_uniq += f" {process_name.lower()}_datamodel.asn"
    pr_path = ' '.join(parent.pr_files) if None not in parent.pr_files else ''
    pr_names = ' '.join(
                      os.path.basename(pr_file) for pr_file in parent.pr_files)
    asn1_modules_o = (name.lower().replace('-', '_') + '.o'
                    for name in process.asn1Modules)

    asn1_mods = ("\"{}\"".format(mod.lower().replace('-', '_'))
                for mod in process.asn1Modules)

    #  Create a .gpr to build the library for the simulator
    lib_gpr = '''project {pr}_Lib is
   for Languages use ("Ada");
   for Library_Name use "{pr}";
   for Library_Interface use ("{pr}", "adaasn1rtl", {other_asn1_modules});
   for Object_Dir use "obj";
   for Library_Dir use "lib";
   for Library_Standalone use "encapsulated";
   for Library_Kind use "dynamic";
   for Source_Dirs use (".");
end {pr}_Lib;'''.format(pr=process_name.lower(),
                        other_asn1_modules=", ".join(asn1_mods))

    #  Create a .gpr to build the Ada generated code
    ada_gpr = '''project {pr}_Ada is
   for Languages use ("Ada");
      for Source_Dirs use (".") & External_As_List ("CODE_PATH", ":");
      for Object_Dir use "../obj";
   end {pr}_Ada;'''.format(pr=process_name.lower())

    pr = process_name.lower()
    simu_script = f'''#!/bin/bash -e
mkdir -p {pr}_simu
cp {pr_path} {asn1_filenames} {pr}_simu
cd {pr}_simu
opengeode {pr_names} --shared
cat {asn1_uniq} >> dataview-uniq.asn

mono $(which asn1.exe) -Ada -typePrefix {ASN1SCC} -equal dataview-uniq.asn
mono $(which asn1.exe) -c -typePrefix {ASN1SCC} -equal dataview-uniq.asn

gprbuild -p -P {process_name.lower()}_lib.gpr
rm -f dataview-uniq.c dataview-uniq.h
asn2aadlPlus dataview-uniq.asn DataView.aadl
aadl2glueC DataView.aadl {process_name.lower()}_interface.aadl
asn2dataModel -toPython dataview-uniq.asn
make -f Makefile.python
echo "errCodes=$(taste-asn1-errCodes ./dataview-uniq.h)" >>datamodel.py
LD_LIBRARY_PATH=./lib:.:$LD_LIBRARY_PATH opengeode-simulator
'''

    LOG.info('Generating Ada code for process ' + str(process_name))

    # In case model has nested states, flatten everything
    Helper.flatten(process, sep=SEPARATOR)

    # Process State aggregations (Parallel states) XXX Add to C backend

    # Find recursively in the AST all state aggregations
    # Format: {'aggregation_name' : [list of ogAST.CompositeState]
    aggregates = Helper.state_aggregations(process)

    # Extract the list of parallel states names inside the composite states
    # of state aggregations XXX add to C generator
    parallel_states = Helper.parallel_states(aggregates)

    # Make an maping {input: {state: transition...}} in order to easily
    # generate the lookup tables for the state machine runtime
    mapping = Helper.map_input_state(process)

    VARIABLES.update(process.variables)

    process_level_decl = []

    # Establish the list of states (excluding START states) XXX update C backend
    full_statelist = set(chain(aggregates.keys(),
                               (name for name in process.mapping.keys()
                                    if not name.endswith(u'START'))))
    reduced_statelist = {s for s in full_statelist if s not in parallel_states}

    if aggregates:
        # Parallel states in a state aggregation may terminate
        full_statelist.add(f'state{SEPARATOR}end')

    #  When a signal is sent from the model a call to a function is emitted
    #  This function has to be provided - either by TASTE (kazoo), or by
    #  the user. Opengeode will generate a stub package for this.
    ri_stub_ads = []
    ri_stub_adb = []

    # Generate an ASN.1 model containing:
    # - the state definition
    # - a type describing the SDL context
    # - all user-defined SDL type (NEWTYPEs...)
    process_asn1 = process_name.capitalize().replace('_', '-')
    asn1_template = [f'{process_asn1}-Datamodel DEFINITIONS ::=',
                      'BEGIN']

    # The ASN.1 module must import the types from other asn1 modules
    types_with_proper_case = []
    imports = []
    for moduleName, sorts in process.DV.exportedTypes.items():
        actual_sorts = []
        for each in sorts:
            MAPPING_SORT_MODULE[each] = moduleName
            if process.DV.types[each].AddedType == "False":
                actual_sorts.append(each)
                types_with_proper_case.append (each)
        sortsAsList = ", ".join(actual_sorts)
        if sortsAsList:
            imports.append(f'{sortsAsList} FROM {moduleName}')
    if types_with_proper_case:
        asn1_template.append(
                "IMPORTS\n   " + "\n   ".join(imports) + ";")

    # Format the state list with ASN.1-compatible syntax
    statelist_asn1 = (state.lower().replace('_', '-')
                      for state in full_statelist)
    states_asn1 = ", ".join(statelist_asn1) \
            or f'{process_asn1.lower()}-has-no-state'
    # Create an ASN.1 definition of the list of states, instead of
    # a native Ada type - this allows external tools to access
    # information about the model without having to parse SDL
    asn1_states_def = f"\n{process_asn1}-States ::= ENUMERATED" \
                      f" {{{states_asn1}}}"

    asn1_template.append(asn1_states_def)

    # Template to generate the full SDL context as a single ASN.1 type
    # This is very useful then to manipulate it from C, Ada or Python as
    # it is then directly accessible and uPER-encodable
    context_elems = []
    if full_statelist:
        # Some systems may have no states - only a start transition
        context_elems.append(f'   state {process_asn1}-States')

    context_elems.append ('init-done BOOLEAN')
    # State aggregation: add list of substates
    for substates in aggregates.values():
        for each in substates:
            context_elems.append(f'{each.statename.lower()}{SEPARATOR}state {process_asn1}-States')

    for var_name, (var_type, def_value) in process.variables.items():
        context_elems.append(f'{var_name.lower()} {type_name(var_type, False)}')

    asn1_context = (f'\n{process_asn1}-Context ::='' SEQUENCE {\n'
            + ",\n   ".join(line.replace("_", "-").replace("'", '"') for line in context_elems)
            + "\n}\n")

    asn1_template.append(asn1_context)

    # Add user-defined NEWTYPEs and CHOICE selector types
    choice_selections = []
    for sortname, sortdef in process.user_defined_types.items():
        if sortdef.type.kind == "SequenceOfType":
            rangeMin = sortdef.type.Min
            rangeMax = sortdef.type.Max
            refType  = sortdef.type.type.ReferencedTypeName
            for refTypeCase in types_with_proper_case:
                if refTypeCase.lower().replace('-', '_') == \
                        refType.lower().replace('-', '_'):
                    break
            asn1_template.append(
                    f'{sortname.replace("_", "-")} ::= SEQUENCE '
                    f'(SIZE ({rangeMin} .. {rangeMax})) OF '
                    f'{refTypeCase.replace("_", "-")}')
        elif sortdef.type.kind == "EnumeratedType":
            keys = []
            for idx, key in enumerate(sortdef.type.EnumValues.keys()):
                # give an index to the enumerations to align with -selection
                # types used in choice index
                keys.append(f'{key}-present({idx+1})')
            asn1_template.append(
                    f'{sortname} ::= ENUMERATED {{' + ", ".join(keys) + '}')
            # We need to convert from the ASN.1 enumerated to the one we created
            choiceTypeModule = MAPPING_SORT_MODULE[sortdef.ChoiceTypeName].replace('-', '_')
            sortAda = sortname.replace('-', '_')
            fromMod = f'{choiceTypeModule}.{ASN1SCC}{sortAda}'
            toMod = f'{process_name}_Datamodel.{ASN1SCC}{sortAda}'
            choice_selections.append(
                    f'function To_{sortAda} (Src : {fromMod}) return {toMod} '
                    f"is ({toMod}'Enum_Val (Src'Enum_Rep));")

    asn1_template.append('END')

    # Write the ASN.1 file (not in case of Stop Condition)
    if not stop_condition:
        with open(process_name.lower() + '_datamodel.asn', 'w') as asn1_file:
            asn1_file.write('\n'.join(asn1_template))

    # Generate the code to declare process-level context
    context_decl = []
    if not stop_condition:
        # but not in stop condition code, since we reuse the context type
        # of the state machine being observed

        ctxt = (f'{LPREFIX} : aliased {ASN1SCC}{process_name.capitalize()}_Context :=\n'
                '      (Init_Done => False,\n       ')
        initial_values = []
        # some parts of the context may have initial values
        for var_name, (var_type, def_value) in process.variables.items():
            if def_value:
                # Expression must be a ground expression, i.e. must not
                # require temporary variable to store computed result
                dst, dstr, dlocal = expression(def_value)
                varbty = find_basic_type(var_type)
                if varbty.kind in ('SequenceOfType', 'OctetStringType'):
                    dstr = array_content(def_value, dstr, varbty)
                assert not dst and not dlocal,\
                        'DCL: Expecting a ground expression'
                initial_values.append(f'{var_name} => {dstr}')

        if initial_values:
            ctxt += ",\n       ".join(initial_values) + ",\n      "
        ctxt += "others => <>);"
        context_decl.append(ctxt)

        # The choice selections will allow to use the present operator
        # together with a variable of the -selection type
        context_decl.extend(choice_selections)
    if stop_condition:
        #  code of stop conditions must use the same type as the main process
        context_decl.append(
                f'{LPREFIX} : {ASN1SCC}{stop_condition}_Context '
                f'renames {stop_condition}.{stop_condition}_ctxt;')
    if simu and not stop_condition:
        # Export the context, so that it can be manipulated from outside
        # (in practice used by the "properties" module.
        context_decl.append(f'pragma export (C, {LPREFIX}, "{LPREFIX}");')
        # Exhaustive simulation needs a backup of the context to quickly undo
        context_decl.append(f'{LPREFIX}_bk: {ASN1SCC}{process_name.capitalize()}_Context;')

    aggreg_start_proc = []
    start_transition = []
    # Continuous State transition id
    if not instance:
        process_level_decl.append('CS_Only : constant := {};'
                                  .format(len(process.transitions)))

        for name, val in process.mapping.items():
            # Test val, in principle there is a value but if the code targets
            # generation of properties, the model may have been cleant up and
            # in that case no value would be set..
            if name.endswith(u'START') and name != u'START' and val:
                process_level_decl.append(u'{name} : constant := {val};'
                                          .format(name=name, val=str(val)))

        # Declare start procedure for aggregate states XXX add in C generator
        # should create one START per "via" clause, TODO later
        for name, substates in aggregates.items():
            proc_name = f'procedure {name}{SEPARATOR}START'
            process_level_decl.append(f'{proc_name};')
            aggreg_start_proc.extend([f'{proc_name} is',
                                      'begin'])
            aggreg_start_proc.extend(u'Execute_Transition ({sub}{sep}START);'
                                     .format(sub=subname.statename,
                                             sep=SEPARATOR)
                                     for subname in substates)
            aggreg_start_proc.extend([f'end {name}{SEPARATOR}START;',
                                     '\n'])

        # Add the declaration of the Execute_Transition procedure
        process_level_decl.append(
                'procedure Execute_Transition (Id : Integer);')

        # Generate the code of the start transition (if process not empty)
        Init_Done = f'{LPREFIX}.Init_Done := True;'
        rand_reset_decl = []
        for rand_g in process.random_generator:
            rand_reset_decl.append(f'Rand_{rand_g}_Pkg.Reset (Gen_{rand_g});');

        start_transition = [
                'procedure Startup is',
                'begin',
                *rand_reset_decl,
                'Execute_Transition (0);'
                if process.transitions else 'null;',
                Init_Done,
                'end Startup;',
                '',
                'begin',
                'Startup;']

    # Generate the TASTE template
    try:
        asn1_modules = '\n'.join(['with {dv};\nuse {dv};'.format(
            dv=dv.replace('-', '_'))
            for dv in process.asn1Modules])
        if process.asn1Modules:
            asn1_modules += '\nwith adaasn1rtl;\nuse adaasn1rtl;'
    except TypeError:
        asn1_modules = '--  No ASN.1 data types are used in this model'

    taste_template = [f'''\
-- This file was generated automatically by OpenGEODE: DO NOT MODIFY IT !

with System.IO;
use System.IO;

with Ada.Unchecked_Conversion;
with Ada.Numerics.Generic_Elementary_Functions;

package body {process_name} is'''
    if not instance else f'''--  Package body for instance - Generated by OpenGEODE (DO NOT EDIT)
package body {process_name} is''']

    generic_spec, instance_decl = "", ""
    if generic:
        generic_spec = "generic\n"
        ri_list = external_ri_list(process)
        if ri_list:
            generic_spec += "    with " + ";\n    with ".join(ri_list) + ';'
    if instance:
        instance_decl = f"with {process.instance_of_name};"

    # print process.fpar
    # FPAR could be set for Context Parameters. They are available here

    # Generate the source file (.ads) header

    # Stop conditions must import the SDL model they observe
    imp_str = f"with {stop_condition}; use {stop_condition};" \
            if stop_condition else ''

    imp_datamodel = (f"with {process_name}_Datamodel; "
                     f"use {process_name}_Datamodel;") \
                             if not stop_condition and not instance else (
                                     f"with {stop_condition}_Datamodel; "
                                     f"use {stop_condition}_Datamodel;"
                                     if stop_condition else "")

    imp_ri = f"with {process_name}_RI;" if not simu and not generic else ""

    rand = ('with Ada.Numerics.Discrete_Random;'
            if process.random_generator else "")
    rand_decl = []
    for each in process.random_generator:
        rand_decl.extend([
            f'type Rand_{each}_ty is new Integer range 1 .. {each};',
            f'package Rand_{each}_Pkg is new  Ada.Numerics.Discrete_Random'\
                    f' (Rand_{each}_ty);',
            f'Gen_{each} : Rand_{each}_Pkg.Generator;',
            f'Num_{each} : Rand_{each}_ty;'])

    ads_template = [f'''\
-- This file was generated automatically by OpenGEODE: DO NOT MODIFY IT !

with Interfaces,
     Interfaces.C.Strings,
     Ada.Characters.Handling;

use Interfaces,
    Interfaces.C.Strings,
    Ada.Characters.Handling;

{asn1_modules}
{imp_datamodel}
{imp_str}
{imp_ri}
{instance_decl}
{rand}
{generic_spec}'''.strip() + f'''
package {process_name} with Elaborate_Body is''']

    ri_stub_ads = [f'''\
--  This file is a stub for the implementation of the required interfaces
--  It is normally overwritten by TASTE with the actual connection to the
--  middleware. If you use Opengeode independently from TASTE you must
--  edit the .adb (body) with your own implementation of these functions.
--  The body stub will be generated only once.

{asn1_modules}

package {process_name}_RI is''']
    ri_stub_adb = [f'''--  Stub generated by OpenGEODE.
--  You can edit this file, it will not be overwritten

package body {process_name}_RI is''']

    dll_api = []
    ads_template.extend(rand_decl)
    if not instance:
        ads_template.extend(context_decl)
    if not generic and not instance and not stop_condition:
        # Add function allowing to trace current state as a string
        ads_template.append(
                f"function Get_State return chars_ptr "
                f"is (New_String "
                f"({ASN1SCC}{process_name}_States'Image ({LPREFIX}.State)))"
                f" with Export, Convention => C, "
                f'Link_Name => "{process_name.lower()}_state";')

    # Declare procedure Startup in .ads
    if not generic:
        ads_template.append(f'procedure Startup'
                            f' with Export, Convention => C,'
                            f' Link_Name => "{process_name}_startup";')
    else:  # function type
        ads_template.append(f'procedure Startup;')

    if simu and not stop_condition:
        ads_template.append('--  API for simulation via DLL')
        dll_api.append('-- API to remotely change internal data')

        # Save/restore state allow one step undo, as needed for model checking
        save_state_decl = 'procedure Save_Context with Export, Convention => C, Link_Name => "_save_context";'
        ads_template.append(save_state_decl)
        restore_state_decl = 'procedure Restore_Context with Export, Convention => C, Link_Name => "_restore_context";'
        ads_template.append(restore_state_decl)
        dll_api.extend([
             "procedure Save_Context is",
             "begin",
            f"{LPREFIX}_bk := {LPREFIX};",
             "end Save_Context;",
             "",
             "procedure Restore_Context is",
             "begin",
            f"{LPREFIX} := {LPREFIX}_bk;",
             "end Restore_Context;",
             ""])

        # Functions to get global context
        ads_template.append(
                f"function Get_Context return access {ASN1SCC}{process_name}_Context is ({LPREFIX}'access)\n"
                f'   with Export, Convention => C, Link_Name => "{process_name.lower()}_context";')
        ads_template.append(
                f"procedure Set_Context (Context : access {ASN1SCC}{process_name}_Context)\n"
                f'   with Export, Convention => C, Link_Name => "set_{process_name.lower()}_context";')

        dll_api.extend([
                f"procedure Set_Context (Context : access {ASN1SCC}{process_name}_Context) is",
                 "begin",
                f"{LPREFIX} := Context.all;",
                 '--  System.IO.Put_Line ("Changed context. State = " & Context.state\'Img);',
                 "end Set_Context;",
                 ""])

    # Generate the the code of the procedures
    inner_procedures_code = []
    for proc in process.content.inner_procedures:
        proc_code, proc_local = generate(proc)
        process_level_decl.extend(proc_local)
        inner_procedures_code.extend(proc_code)
        if proc.exported:
            # Exported procedures must be declared in the .ads
            pi_header = procedure_header(proc)
            ads_template.append(f'{pi_header};')
            if not proc.external and not generic:
                ads_template.append(
                   f'pragma Export (C, p{SEPARATOR}{proc.inputString}, "_{proc.inputString}");')

    # Generate the code for the process-level variable declarations
    taste_template.extend(process_level_decl)

    # Add the code of the procedures definitions
    taste_template.extend(inner_procedures_code)

    # Generate the code of the START procedures of state aggregations
    # XXX to be added to C generator
    taste_template.extend(aggreg_start_proc)

    # Add the code of the DLL interface
    taste_template.extend(dll_api)

    # Generate the code for each input signal (provided interface) and timers
    for signal in process.input_signals + [
                        {'name': timer} for timer in process.timers]:
        if stop_condition:
            # dont generate anything in stop_condition functions
            break

        signame = signal.get('name', 'START')
        if signame == 'START':
            continue
        pi_header = f'procedure {signame}'
        param_name = signal.get('param_name') or f'{signame}_param'
        # Add (optional) PI parameter (only one is possible in TASTE PI)
        if 'type' in signal:
            typename = type_name(signal['type'])
            pi_header += f'({param_name}: in out {typename})'

        # Add declaration of the provided interface in the .ads file
        ads_template.append(f'--  Provided interface "{signame}"')
        ads_template.append(pi_header + ';')
        if not generic:
            ads_template.append(
                    f'pragma Export(C, {signame}, "{process_name.lower()}_PI_{signame}");')

        if simu:
            # Generate code for the mini-cv template
            params = [(param_name, type_name(signal['type'], use_prefix=False),
                      'IN')] if 'type' in signal else []
            minicv.append(aadl_template(signame, params, 'RI'))

        pi_header += ' is'
        taste_template.append(pi_header)
        taste_template.append('begin')

        def execute_transition(state):
            ''' Generate the code that triggers the transition for the current
                state/input combination '''
            input_def = mapping[signame].get(state)
            # Check for nested states to call optional exit procedures
            # (we may exit from more than one state, the exit procedures must
            #  be called in the right order)
            state_tree = state.split(SEPARATOR)
            context = process
            exitlist = []
            current = ''
            trans = input_def and process.transitions[input_def.transition_id]
            while state_tree:
                current = current + state_tree.pop(0)
                for comp in context.composite_states:
                    if current.lower() == comp.statename.lower():
                        if comp.exit_procedure:
                            exitlist.append(current)
                        context = comp
                        current = current + SEPARATOR
                        break
            for each in reversed(exitlist):
                # Here we add a call to the exit procedure of nested states
                # when we exit the state due to a transition in the superstate
                # not due to a return statement from within the substate
                # this other case is handled in Helper.py when flattening
                # the model.
                # The exit here is added only for transitions triggered by an
                # INPUT. The continuous signals are not processed here
                if trans and all(each.startswith(trans_st)
                                 for trans_st in trans.possible_states):
                    taste_template.append(f'p{SEPARATOR}{each}{SEPARATOR}exit;')

            if input_def:
                for inp in input_def.parameters:
                    # Assign the (optional and unique) parameter
                    # to the corresponding process variable
                    taste_template.append(f'{LPREFIX}.{inp} := {param_name};')
                # Execute the correponding transition
                if input_def.transition:
                    taste_template.append(u'Execute_Transition ({idx});'
                            .format(idx=input_def.transition_id))
                else:
                    taste_template.append('Execute_Transition (CS_Only);')
            else:
                taste_template.append('Execute_Transition (CS_Only);')

        if not instance:
            taste_template.append('case {}.state is'.format(LPREFIX))

        def case_state(state):
            ''' Recursive function (in case of state aggregation) to generate
                the code that calls the proper transition according
                to the current state
                The input name is in signame
            '''
            if state.endswith(u'START'):
                return
            taste_template.append(f'when {ASN1SCC}{state} =>')
            input_def = mapping[signame].get(state)
            if state in aggregates.keys():
                # State aggregation:
                # - find which substate manages this input
                # - add a swich case on the corresponding substate
                taste_template.append(u'-- this is a state aggregation')
                for sub in aggregates[state]:
                    if [a for a in sub.mapping.keys()
                            if a in mapping[signame].keys()]:
                        taste_template.append(u'case '
                                              u'{ctxt}.{sub}{sep}state is'
                                              .format(ctxt=LPREFIX,
                                                     sub=sub.statename,
                                                     sep=SEPARATOR))
                        for par in sub.mapping.keys():
                            case_state(par)
                        taste_template.append('when others =>')
                        taste_template.append('null;')
                        taste_template.append('end case;')
                        break
                else:
                    # Input is not managed in the state aggregation
                    if input_def:
                        # check if it is managed one level above
                        execute_transition(state)
                    taste_template.append('null;')
            else:
                execute_transition(state)

        if not instance:
            for each_state in reduced_statelist:
                case_state(each_state)
            taste_template.append('when others =>')
            taste_template.append('Execute_Transition (CS_Only);')
            taste_template.append('end case;')
        else:
            inst_call = f"{process_name}_Instance.{signame}"
            if 'type' in signal:
                inst_call += f" ({param_name})"
            taste_template.append(f"{inst_call};")

        taste_template.append(f'end {signame};')
        taste_template.append('\n')

    #  add call to startup function for instances
    if instance:
        taste_template.extend(['procedure Startup is',
                               'begin',
                               f'{process_name}_Instance.Startup;',
                               'end Startup;',
                               ''])

    # for the .ads file, generate the declaration of the required interfaces
    # output signals are the asynchronous RI - only one parameter
    for signal in process.output_signals:
        sig = signal['name']
        param_name = signal.get('param_name') or f'{sig}_param'
        # Add (optional) RI parameter
        # Paramless TMs: when targetting simulation, the name of the TM is
        # passed as single parameter. This allows the simualor to handle them
        # dynamically, with a single callback function for all TMs
        param_spec = '' if not simu else " (TM : chars_ptr)"
        if 'type' in signal:
            typename = type_name(signal['type'])
            param_spec = f' ({param_name} : in out {typename}{"; Size : Integer" if SHARED_LIB else ""})'
        if not generic:
            ads_template.append(u'--  {}equired interface "{}"'
                                .format("Paramless r" if not 'type' in signal
                                    else "R", sig))
        if simu:
            # When generating a shared library, we need a callback mechanism
            code = [f'type {sig}_T is access procedure{param_spec};',
                    f'pragma Convention (Convention => C, Entity => {sig}_T);',
                    f'RI{SEPARATOR}{sig} : {sig}_T;',
                    f'procedure Register_{sig} (Callback : {sig}_T);',
                    f'pragma Export(C, Register_{sig}, "register_{sig}");']
            ads_template.extend(code)

            # Generate code for the mini-cv template
            params = [(param_name,
                       type_name(signal['type'], use_prefix=False),
                      'IN')] if 'type' in signal else []

            minicv.append(aadl_template(sig, params, 'PI'))

            code = [f'procedure Register_{sig} (Callback : {sig}_T) is',
                     'begin',
                    f'RI{SEPARATOR}{sig} := Callback;',
                    f'end Register_{sig};',
                    '']
            taste_template.extend(code)
        elif not generic:
            ads_template.append(f'procedure RI{SEPARATOR}{sig}{param_spec} '
                    f'renames {process_name}_RI.{sig};')
            ri_stub_ads.append(f'procedure {sig}{param_spec};')
            ri_stub_adb.append(f'procedure {sig}{param_spec} is null;')
            #  TASTE generates the pragma import in <function>_ri.ads
            #  therefore do not generate it in the .ads
            # ads_template.append(f'pragma Import (C, RI{SEPARATOR}{sig}, "{process_name.lower()}_RI_{sig}");')

    # for the .ads file, generate the declaration of the external procedures
    for proc in (proc for proc in process.procedures if proc.external):
        sig = proc.inputString
        ri_header = f'procedure RI{SEPARATOR}{sig}'
        params = []
        params_spec = ""
        if simu:
            # For simulators: add the TM name as first parameter
            params.append("TM : chars_ptr")
        for param in proc.fpar:
            typename = type_name(param['type'])
            name     = param['name']
            if param['direction'] == 'in':
                direct = 'in out'
            else:
                direct = 'out'
            shared=f"; {name}_Size : Integer" if SHARED_LIB else ""

            params.append(f'{name} : {direct} {typename}{shared}')
        if params:
            params_spec = " ({})".format("; ".join(params))
            ri_header += params_spec
        ads_template.append(f'--  Sync required interface "{sig}"')
        if simu:
            # As for async TM, generate a callback mechanism
            code = [f"type {sig}_T is access procedure{params_spec};",
                    f'pragma Convention(Convention => C, Entity => {sig}_T);',
                    f'RI{SEPARATOR}{sig} : {sig}_T;',
                    f'procedure Register_{sig}(Callback: {sig}_T);',
                    f'pragma Export(C, Register_{sig}, "register_{sig}");']

            ads_template.extend(code)

            code = [f'procedure Register_{sig} (Callback : {sig}_T) is',
                     'begin',
                    f'RI{SEPARATOR}{sig} := Callback;',
                    f'end Register_{sig};',
                     '']
            taste_template.extend(code)

        elif not generic:
            ads_template.append(f'{ri_header} renames {process_name}_RI.{sig};')
            ri_stub_ads.append(f'procedure {sig}{params_spec};')
            ri_stub_adb.append(f'procedure {sig}{params_spec} is null;')

    # for the .ads file, generate the declaration of timers set/reset functions
    for timer in process.timers:
        if stop_condition:
            # don't generte timer code for stop conditions
            break
        ads_template.append(f'--  Timer {timer} SET and RESET functions')
        if simu:
            # Declare callback registration for the SET and RESET functions
            ads_template.append(u'type SET_{}_T is access procedure'
                                 '(name: chars_ptr; duration: Asn1Int);'
                                .format(timer))
            ads_template.append(u'type RESET_{}_T is access procedure'
                                '(name: chars_ptr);'.format(timer))
            for each in ('', 'RE'):
                ads_template.append(u'pragma Convention (Convention => C,'
                                    u' Entity => {re}SET_{t}_T);'
                                    .format(re=each, t=timer))
                ads_template.append(u'{re}SET_{t} : {re}SET_{t}_T;'
                                    .format(re=each, t=timer))
                ads_template.append(u'procedure Register_{re}SET_{t}'
                                    u'(Callback: {re}SET_{t}_T);'
                                    .format(re=each, t=timer))
                ads_template.append(u'pragma Export(C, Register_{re}SET_{t},'
                                    u' "register_{re}SET_{t}");'
                                    .format(re=each, t=timer))
            # Code for the SET/RESET timer callback registration
            for each in ('', 'RE'):
                taste_template.append(u'procedure Register_{re}SET_{t}'
                                      u'(Callback:{re}SET_{t}_T) is'
                                      .format(re=each, t=timer))
                taste_template.append(u'begin')
                taste_template.append(u'{re}SET_{t} := Callback;'
                                      .format(re=each, t=timer))
                taste_template.append(u'end Register_{re}SET_{t};'
                                      .format(re=each, t=timer))
                taste_template.append('')

        elif not generic:
            procname = process_name.lower()
            ads_template.append(
               f'procedure SET_{timer} (Val : in out asn1SccT_UInt32) '
               f'renames {process_name}_RI.Set_{timer};')
            ri_stub_ads.append(f'procedure SET_{timer} (Val : in out asn1SccT_UInt32);')
            ri_stub_adb.append(f'procedure SET_{timer} (Val : in out asn1SccT_UInt32) is null;')