AdaGenerator.py

#!/usr/bin/env python
# -*- 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) 2012-2013 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 singledispatch import singledispatch

import ogAST
import Helper

LOG = logging.getLogger(__name__)

__all__ = ['generate']

# reference to the ASN.1 Data view and to the visible variables (in scope)
TYPES = None
VARIABLES = {}
LOCAL_VAR = {}
# List of output signals and procedures
OUT_SIGNALS = []
PROCEDURES = []

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

UNICODE_SEP = u'\u00dc'
LPREFIX = u'ctxt'

@singledispatch
def generate(*args, **kwargs):
    ''' Generate the code for an item of the AST '''
    raise TypeError('[AdaGenerator] Unsupported AST construct')
    return [], []


# Processing of the AST
@generate.register(ogAST.Process)
def _process(process, simu=False, **kwargs):
    ''' Generate the code for a complete process (AST Top level) '''
    process_name = process.processName
    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 = process_name + u'_ctxt'

    # 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 = ' '.join(parent.asn1_filenames)
    asn1_uniq = ' '.join(each for each in parent.asn1_filenames
                         if each != 'dataview-uniq.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 = (name.lower().replace('-', '_') + '.o'
                    for name in process.asn1Modules)

    simu_script = '''#!/bin/bash -e
rm -rf {pr}_simu
mkdir -p {pr}_simu
cp {pr_path} {asn1} {pr}_simu
cd {pr}_simu
opengeode {pr_names} --shared
cat {uniq} >> dataview-uniq.asn '''.format(pr=process_name.lower(),
                                           asn1=asn1_filenames,
                                           pr_path=pr_path,
                                           uniq=asn1_uniq or '/dev/null',
                                           pr_names=pr_names)

    if asn1_filenames:
        simu_script += '''
asn1.exe -Ada -typePrefix asn1Scc -equal {asn1}
asn1.exe -c -typePrefix asn1Scc -equal {asn1}'''.format(asn1=asn1_filenames)

    simu_script += '''
gnatmake -gnat2012 -c *.adb
gnatbind -n -Llib{pr} {pr}
gnatmake -c -gnat2012 b~{pr}.adb
gcc -shared -fPIC -o lib{pr}.so b~{pr}.o {pr}.o {asn1_mod} adaasn1rtl.o -lgnat
rm -f dataview-uniq.c dataview-uniq.h
asn2aadlPlus dataview-uniq.asn DataView.aadl
aadl2glueC DataView.aadl {pr}_interface.aadl
asn2dataModel -toPython dataview-uniq.asn
make -f Makefile.python
echo "errCodes=$(taste-asn1-errCodes ./dataview-uniq.h)" >>datamodel.py
LD_LIBRARY_PATH=. opengeode-simulator
'''.format(pr=process_name.lower(),
           asn1_files=asn1_filenames,
           asn1_mod=' '.join(asn1_modules))


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

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

    # 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.viewkeys(),
                               (name for name in process.mapping.iterkeys()
                                    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(u'{}finished'.format(UNICODE_SEP))

    if full_statelist:
        process_level_decl.append(u'type States is ({});'
                            .format(u', '.join(full_statelist) or u'No_State'))

    # Generate the code to declare process-level context
    process_level_decl.extend(['type {}_Ty is'.format(LPREFIX), 'record'])

    if full_statelist:
        process_level_decl.append('state : States;')

    process_level_decl.append('initDone : Boolean := False;')

    # State aggregation: add list of substates (XXX to be added in C generator)
    for substates in aggregates.viewvalues():
        for each in substates:
            process_level_decl.append(u'{}{}state: States;'
                                      .format(each.statename, UNICODE_SEP))

    for var_name, (var_type, def_value) in process.variables.viewitems():
        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'
        process_level_decl.append(
                        u'{n} : aliased {sort}{default};'
                        .format(n=var_name,
                                sort=type_name(var_type),
                                default=u' := ' + dstr if def_value else u''))

    process_level_decl.append('end record;')
    process_level_decl.append('{ctxt}: {ctxt}_Ty;'.format(ctxt=LPREFIX))
    if simu:
        # Exhaustive simulation needs a backup of the context to quickly undo
        process_level_decl.append('{ctxt}_bk: {ctxt}_Ty;'.format(ctxt=LPREFIX))

    process_level_decl.append('CS_Only  : constant Integer := {};'
                              .format(len(process.transitions)))


    for name, val in process.mapping.viewitems():
        if name.endswith(u'START') and name != u'START':
            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
    aggreg_start_proc = []
    for name, substates in aggregates.viewitems():
        proc_name = u'procedure {}{}START'.format(name, UNICODE_SEP)
        process_level_decl.append(u'{};'.format(proc_name))
        aggreg_start_proc.extend([u'{} is'.format(proc_name),
                                  'begin'])
        aggreg_start_proc.extend(u'runTransition({sub}{sep}START);'
                                 .format(sub=subname.statename,
                                         sep=UNICODE_SEP)
                                 for subname in substates)
        aggreg_start_proc.extend([u'end {}{}START;'
                                 .format(name, UNICODE_SEP),
                                 '\n'])

    # Add the declaration of the runTransition procedure, if needed
    if process.transitions:
        process_level_decl.append('procedure runTransition(Id: Integer);')

    # Generate the code of the start transition (if process not empty)
    if not simu:
        start_transition = ['begin',
                            'runTransition(0);'] if process.transitions else []
    else:
        start_transition = ['procedure Startup;',
                            'pragma Export(C, Startup, "{}_startup");'
                            .format(process_name),
                            'procedure Startup is',
                            'begin',
                            '   runTransition(0);' if process.transitions
                                                   else 'null;',
                            'end 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 = ['''\
-- This file was generated automatically: DO NOT MODIFY IT !

with System.IO;
use System.IO;

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

{dataview}

with Interfaces;
use Interfaces;
{C}
package body {process_name} is'''.format(process_name=process_name,
                                         dataview=asn1_modules,
                                         C='with Interfaces.C.Strings;\n'
                                           'use Interfaces.C.Strings;'
                                            if simu else '')]

    # Generate the source file (.ads) header
    ads_template = ['''\
-- This file was generated automatically: DO NOT MODIFY IT !

{dataview}
{C}

package {process_name} is'''.format(process_name=process_name,
                                    dataview=asn1_modules,
                                    C='with Interfaces.C.Strings;\n'
                                      'use Interfaces.C.Strings;'
                                        if simu else '')]

    dll_api = []
    if simu:
        ads_template.append('--  API for simulation via DLL')
        dll_api.append('-- API to remotely change internal data')
        # Add function allowing to trace current state as a string
        process_level_decl.append("function get_state return chars_ptr "
                                  "is (New_String(states'Image({ctxt}.state)))"
                                  " with Export, Convention => C, "
                                  'Link_Name => "{name}_state";'
                                  .format(name=process_name, ctxt=LPREFIX))
        set_state_decl = "procedure set_state(new_state: chars_ptr)"
        ads_template.append("{};".format(set_state_decl))
        ads_template.append('pragma Export(C, set_state, "_set_state");')
        dll_api.append("{} is".format(set_state_decl))
        dll_api.append("begin")
        dll_api.append("{}.state := States'Value(Value(new_state));"
                       .format(LPREFIX))
        dll_api.append("end set_state;")
        dll_api.append("")

        # Save/restore state allow one step undo, as needed for model checking
        save_state_decl = "procedure save_context"
        restore_state_decl = "procedure restore_context"
        ads_template.append("{};".format(save_state_decl))
        ads_template.append('pragma Export(C, save_context, "_save_context");')
        ads_template.append("{};".format(restore_state_decl))
        ads_template.append('pragma Export(C, restore_context, "_restore_context");')
        dll_api.append("{} is".format(save_state_decl))
        dll_api.append("begin")
        dll_api.append("{ctxt} := {ctxt}_bk;".format(ctxt=LPREFIX))
        dll_api.append("end save_context;")
        dll_api.append("")
        dll_api.append("{} is".format(restore_state_decl))
        dll_api.append("begin")
        dll_api.append("{ctxt}_bk := {ctxt};".format(ctxt=LPREFIX))
        dll_api.append("end restore_context;")
        dll_api.append("")

        # interface to get/set state aggregations XXX add to C generator
        for substates in aggregates.viewvalues():
            for each in substates:
                process_level_decl.append(
                        u"function get_{name}_state return chars_ptr "
                        u"is (New_String(states'Image({ctxt}.{name}{sep}state)"
                        ")) with Export, Convention => C, "
                        'Link_Name => "{proc}_{name}_state";'
                        .format(name=each.statename, ctxt=LPREFIX,
                                proc=process_name, sep=UNICODE_SEP))

        # Functions to get gobal variables (length and value)
        for var_name, (var_type, _) in process.variables.viewitems():
            # Getters for local variables
# Removed size - this was needed by swig only, not ctypes
#           process_level_decl.append("function l_{name}_size return integer "
#                                    "is ({prefix}.{name}'Size/8) with Export,"
#                                    " Convention => C,"
#                                    ' Link_Name => "{name}_size";'
#                                    .format(prefix=LPREFIX, name=var_name))
            process_level_decl.append("function l_{name}_value"
                                     " return access {sort} "
                                     "is ({prefix}.{name}'access) with Export,"
                                     " Convention => C,"
                                     ' Link_Name => "{name}_value";'
                                     .format(prefix=LPREFIX, name=var_name,
                                              sort=type_name(var_type)))
            # Setters for local variables
            setter_decl = "procedure dll_set_l_{name}(value: access {sort})"\
                          .format(name=var_name, sort=type_name(var_type))
            ads_template.append('{};'.format(setter_decl))
            ads_template.append('pragma Export(C, dll_set_l_{name},'
                                ' "_set_{name}");'.format(name=var_name))
            dll_api.append('{} is'.format(setter_decl))
            dll_api.append('begin')
            dll_api.append('{}.{} := value.all;'.format(LPREFIX, var_name))
            dll_api.append('end dll_set_l_{};'.format(var_name))
            dll_api.append('')

    # 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)

    # 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.lower()} for timer in process.timers]:
        signame = signal.get('name', u'START')
        if signame == u'START':
            continue
        pi_header = u'procedure {sig_name}'.format(sig_name=signame)
        param_name = signal.get('param_name') \
                                or u'{}_param'.format(signame)
        # Add (optional) PI parameter (only one is possible in TASTE PI)
        if 'type' in signal:
            typename = type_name(signal['type'])
            pi_header += u'({pName}: access {sort})'.format(
                                        pName=param_name, sort=typename)

        # Add declaration of the provided interface in the .ads file
        ads_template.append(u'--  Provided interface "{}"'.format(signame))
        ads_template.append(pi_header + ';')
        ads_template.append(u'pragma Export(C, {name}, "{proc}_{name}");'
                             .format(name=signame, proc=process_name))

        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 procedure
            state_tree = state.split(UNICODE_SEP)
            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 + UNICODE_SEP
                        break
            for each in reversed(exitlist):
                if trans and all(each.startswith(trans_st)
                                 for trans_st in trans.possible_states):
                    taste_template.append(u'p{sep}{ref}{sep}exit;'
                                          .format(ref=each, sep=UNICODE_SEP))

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

        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(u'when {state} =>'.format(state=state))
            input_def = mapping[signame].get(state)
            if state in aggregates.viewkeys():
                # 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.viewkeys()
                            if a in mapping[signame].viewkeys()]:
                        taste_template.append(u'case '
                                              u'{ctxt}.{sub}{sep}state is'
                                              .format(ctxt=LPREFIX,
                                                     sub=sub.statename,
                                                     sep=UNICODE_SEP))
                        for par in sub.mapping.viewkeys():
                            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)

        map(case_state, reduced_statelist) # XXX update C generator

        taste_template.append('when others =>')
        taste_template.append('runTransition(CS_Only);')
        taste_template.append('end case;')
        taste_template.append(u'end {};'.format(signame))
        taste_template.append('\n')

    # 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:

        param_name = signal.get('param_name') \
                                or u'{}_param'.format(signal['name'])
        # 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 = u'({pName}: access {sort}{shared})' \
                         .format(pName=param_name,
                                 sort=typename,
                                 shared=u'; Size: Integer'
                                        if SHARED_LIB else '')
        ads_template.append(u'--  {}equired interface "{}"'
                            .format("Paramless r" if not 'type' in signal
                                else "R", signal['name']))
        if simu:
            # When generating a shared library, we need a callback mechanism
            ads_template.append(u'type {}_T is access procedure{};'
                                .format(signal['name'], param_spec))
            ads_template.append(u'pragma Convention(Convention => C,'
                                u' Entity => {}_T);'.format(signal['name']))
            ads_template.append(u'RI{sep}{sig} : {sig}_T;'
                                .format(sep=UNICODE_SEP, sig=signal['name']))
            ads_template.append(u'procedure Register_{sig}(Callback: {sig}_T);'
                                .format(sig=signal['name']))
            ads_template.append(u'pragma Export(C, Register_{sig},'
                                ' "register_{sig}");'
                                .format(sig=signal['name']))

            # 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(signal['name'], params, 'PI'))

            taste_template.append(u'procedure Register_{sig}'
                                  u'(Callback:{sig}_T) is'
                                  .format(sig=signal['name']))
            taste_template.append(u'begin')
            taste_template.append(u'RI{sep}{sig} := Callback;'
                                  .format(sep=UNICODE_SEP, sig=signal['name']))
            taste_template.append(u'end Register_{};'.format(signal['name']))
            taste_template.append(u'')
        else:
            ads_template.append(u'procedure RI{}{}{};'
                                .format(UNICODE_SEP,
                                        signal['name'],
                                        param_spec))
            ads_template.append(u'pragma import(C, RI{sep}{sig},'
                                u' "{proc}_RI_{sig}");'
                                .format(sep=UNICODE_SEP,
                                        sig=signal['name'],
                                        proc=process_name))

    # for the .ads file, generate the declaration of the external procedures
    for proc in (proc for proc in process.procedures if proc.external):
        ri_header = u'procedure RI{sep}{sig_name}'.format(
                                                     sep=UNICODE_SEP,
                                                     sig_name=proc.inputString)
        params = []
        params_spec = u""
        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'])
            params.append(u'{par[name]}: access {sort}{shared}'
                          .format(par=param,
                                  sort=typename,
                                  shared=u"; {}_Size: Integer"
                                         .format(param['name'])
                                         if SHARED_LIB else ""))
        if params:
            params_spec = "({})".format("; ".join(params))
            ri_header += params_spec
        ads_template.append(u'--  Sync required interface "{}"'
                            .format(proc.inputString))
        if simu:
            # As for async TM, generate a callback mechanism
            ads_template.append(u"type {}_T is access procedure{};"
                                .format(proc.inputString, params_spec))
            ads_template.append(u'pragma Convention(Convention => C,'
                                u' Entity => {}_T);'.format(proc.inputString))
            ads_template.append(u'RI{sep}{sig} : {sig}_T;'
                                .format(sep=UNICODE_SEP, sig=proc.inputString))
            ads_template.append(u'procedure Register_{sig}(Callback: {sig}_T);'
                                .format(sig=proc.inputString))
            ads_template.append(u'pragma Export(C, Register_{sig},'
                                u' "register_{sig}");'
                                .format(sig=proc.inputString))
            taste_template.append(u'procedure Register_{sig}'
                                  '(Callback:{sig}_T) is'
                                  .format(sig=proc.inputString))
            taste_template.append(u'begin')
            taste_template.append(u'RI{sep}{sig} := Callback;'
                                  .format(sep=UNICODE_SEP,
                                          sig=proc.inputString))
            taste_template.append(u'end Register_{};'.format(proc.inputString))
            taste_template.append(u'')

        else:
            ads_template.append(ri_header + u';')
            ads_template.append(u'pragma import(C, RI{sep}{sig},'
                                u' "{proc}_RI_{sig}");'
                                .format(sep=UNICODE_SEP,
                                        sig=proc.inputString,
                                        proc=process_name))

    # for the .ads file, generate the declaration of timers set/reset functions
    for timer in process.timers:
        ads_template.append(u'--  Timer {} SET and RESET functions'
                            .format(timer))
        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('pragma Convention(Convention => C,'
                                    ' Entity => {re}SET_{t}_T);'
                                    .format(re=each, t=timer))
                ads_template.append('{re}SET_{t} : {re}SET_{t}_T;'
                                    .format(re=each, t=timer))
                ads_template.append('procedure Register_{re}SET_{t}'
                                    '(Callback: {re}SET_{t}_T);'
                                    .format(re=each, t=timer))
                ads_template.append('pragma Export(C, Register_{re}SET_{t},'
                                    ' "register_{re}SET_{t}");'
                                    .format(re=each, t=timer))
            # Code for the SET/RESET timer callback registration
            for each in ('', 'RE'):
                taste_template.append('procedure Register_{re}SET_{t}'
                                      '(Callback:{re}SET_{t}_T) is'
                                      .format(re=each, t=timer))
                taste_template.append('begin')
                taste_template.append('{re}SET_{t} := Callback;'
                                      .format(re=each, t=timer))
                taste_template.append('end Register_{re}SET_{t};'
                                      .format(re=each, t=timer))
                taste_template.append('')

        else:
            ads_template.append(u'procedure SET_{}(val: access asn1SccT_UInt32);'
                .format(timer))
            ads_template.append(
                u'pragma import(C, SET_{timer}, "{proc}_RI_set_{timer}");'
                .format(timer=timer, proc=process_name))
            ads_template.append(u'procedure RESET_{};'.format(timer))
            ads_template.append(
                u'pragma import(C, RESET_{timer}, "{proc}_RI_reset_{timer}");'
                .format(timer=timer, proc=process_name))

    # If the process has no input, output, procedures, or timers, then Ada
    # will not compile the body - generate a pragma to fix this
    if not process.timers and not process.procedures \
            and not process.input_signals and not process.output_signals:
        ads_template.append('pragma elaborate_body;')

    # Transform inner labels to floating labels
    Helper.inner_labels_to_floating(process)

    # Generate the code for all transitions
    code_transitions = []
    local_decl_transitions = []
    for proc_tr in process.transitions:
        code_tr, tr_local_decl = generate(proc_tr)
        code_transitions.append(code_tr)
        local_decl_transitions.extend(tr_local_decl)

    # Generate code for the floating labels
    code_labels = []
    for label in process.content.floating_labels:
        code_label, label_decl = generate(label)
        local_decl_transitions.extend(label_decl)
        code_labels.extend(code_label)

    # Generate the code of the runTransition procedure, if needed
    if process.transitions:
        taste_template.append('procedure runTransition(Id: Integer) is')
        taste_template.append('trId : Integer := Id;')
        if process.cs_mapping:
            taste_template.append(
                              'msgPending : aliased Asn1Boolean := True;')

        # Declare the local variables needed by the transitions in the template
        taste_template.extend(set(local_decl_transitions))
        taste_template.append('begin')

        # Generate a loop that ends when a next state is reached
        # (there can be chained transition when entering a nested state)
        taste_template.append('while (trId /= -1) loop')

        # Generate the switch-case on the transition id
        taste_template.append('case trId is')

        for idx, val in enumerate(code_transitions):
            taste_template.append(u'when {idx} =>'.format(idx=idx))
            val = [u'{line}'.format(line=l) for l in val]
            if val:
                taste_template.extend(val)
            else:
                taste_template.append('null;')

        taste_template.append('when CS_Only =>')
        taste_template.append('trId := -1;')
        taste_template.append('goto next_transition;')

        taste_template.append('when others =>')
        taste_template.append('null;')

        taste_template.append('end case;')
        if code_labels:
            # Due to nested states (chained transitions) jump over label code
            # (NEXTSTATEs do not return from runTransition)
            taste_template.append('goto next_transition;')

        # Add the code for the floating labels
        taste_template.extend(code_labels)

        taste_template.append('<<next_transition>>')

        # After completing active transition(s), check continuous signals:
        #     - Check current state(s)
        #     - For each continuous signal generate code (test+transition)
        # XXX add to C backend
        # Check Queue: TODO implement when simu=True
        if process.cs_mapping and not simu:
            taste_template.append('--  Process continuous signals')
            taste_template.append('if {}.initDone then'.format(LPREFIX))
            taste_template.append("Check_Queue(msgPending'access);")
            taste_template.append('end if;')
            ads_template.append(
                    u'procedure Check_Queue(res: access Asn1Boolean);')
            ads_template.append(
                u'pragma import(C, Check_Queue, "{proc}_check_queue");'
                .format(proc=process_name))
        else:
            taste_template.append('null;')

        # Process the continuous signals in state aggregations first
        done = []
        sep = 'if '
        last = ''
        for cs, agg in product(process.cs_mapping.viewitems(),
                               aggregates.viewitems()):
            (statename, cs_item), (agg_name, substates) = cs, agg
            for each in substates:
                if statename in each.mapping.viewkeys():
                    taste_template.append(u'{first}if not msgPending and '
                            u'trId = -1 and '
                            u'{ctxt}.state = {s1} and '
                            u'{ctxt}.{s2}{unisep}state = {s3} then'
                            .format(ctxt=LPREFIX, s1=agg_name,
                                s2=each.statename, unisep=UNICODE_SEP,
                                s3=statename, first='els' if done else ''))
                    # Change priority 0 (no priority set) to lowest priority
                    lowest_priority = max(item.priority for item in cs_item)
                    for each in cs_item:
                        if each.priority == 0:
                            each.priority = lowest_priority + 1
                    for provided_clause in sorted(cs_item,
                                                 key=lambda itm: itm.priority):
                        taste_template.append(u'-- Priority {}'
                                             .format(provided_clause.priority))
                        trId = process.transitions.index\
                                            (provided_clause.transition)
                        code, loc = generate(provided_clause.trigger,
                                             branch_to=trId,
                                             sep=sep, last=last)
                        sep='elsif '
                        taste_template.extend(code)
                    done.append(statename)
                    taste_template.append(u'end if; -- inner')  # inner if
                    sep = 'if '
                    break
        for statename in process.cs_mapping.viewkeys() - done:
            cs_item = process.cs_mapping[statename]
            taste_template.append(u'-- Now what')
            taste_template.append(u'{first}if not msgPending and '
                    u'trId = -1 and {}.state = {} then'
                    .format(LPREFIX, statename, first='els' if done else ''))
            # Change priority 0 (no priority set) to lowest priority
            lowest_priority = max(item.priority for item in cs_item)
            for each in cs_item:
                if each.priority == 0:
                    each.priority = lowest_priority + 1
            for provided_clause in sorted(cs_item,
                                          key=lambda itm: itm.priority):
                taste_template.append(u'-- Priority {}'
                                      .format(provided_clause.priority))
                trId = process.transitions.index(provided_clause.transition)
                code, loc = generate(provided_clause.trigger,
                                     branch_to=trId, sep=sep, last=last)
                sep='elsif '
                taste_template.extend(code)
            taste_template.append(u'end if;') # inner if
            taste_template.append(u'end if;') # current state
            sep = 'if '

        taste_template.append('end loop;')
        taste_template.append('{ctxt}.initDone := True;'.format(ctxt=LPREFIX))
        taste_template.append('end runTransition;')
        taste_template.append('\n')

    # Add code of the package elaboration
    taste_template.extend(start_transition)
    taste_template.append('end {process_name};'
            .format(process_name=process_name))

    ads_template.append('end {process_name};'
            .format(process_name=process_name))

    with open(process_name.lower() + os.extsep + 'adb', 'w') as ada_file:
        ada_file.write(
                u'\n'.join(format_ada_code(taste_template)).encode('latin1'))

    with open(process_name.lower() + os.extsep + 'ads', 'w') as ada_file:
        ada_file.write(
                u'\n'.join(format_ada_code(ads_template)).encode('latin1'))

    if simu:
        with open(u'{}_interface.aadl'
                  .format(process_name.lower()), 'w') as aadl:
            aadl.write(u'\n'.join(minicv).encode('latin1'))
        script = '{}_simu.sh'.format(process_name.lower())
        with open(script, 'w') as bash_script:
            bash_script.write(simu_script)
        os.chmod(script, os.stat(script).st_mode | stat.S_IXUSR)


def write_statement(param, newline):
    ''' Generate the code for the special "write" operator '''
    code = []
    string = ''
    local = []
    basic_type = find_basic_type(param.exprType) or {}
    type_kind = basic_type.kind
    if isinstance(param, ogAST.ExprAppend):
        # Append: call Put_Line separately for each side of the expression
        st1, _, lcl1= write_statement(param.left, newline = False)
        st2, _, lcl2 = write_statement(param.right, newline = False)
        code.extend(st1)
        code.extend(st2)
        local.extend(lcl1)
        local.extend(lcl2)
    elif type_kind.endswith('StringType'):
        if isinstance(param, ogAST.PrimStringLiteral):
            # Raw string
            code.append(u'Put("{}");'
                        .format(param.value[1:-1].replace('"', "'")))
        else:
            code, string, local = expression(param)
            if type_kind == 'OctetStringType':
                # Octet string -> convert to Ada string
                last_it = u""
                if isinstance(param, ogAST.PrimSubstring):
                    range_str = u"{}'Range".format(string)
                    iterator = u"i - {}'First + 1".format(string)
                elif basic_type.Min == basic_type.Max:
                    range_str = u"{}.Data'Range".format(string)
                    string += u".Data"
                    iterator = u"i"
                else:
                    range_str = u"1 .. {}.Length".format(string)
                    string += u".Data"
                    iterator = u"i"
                    last_it = u"({})".format(range_str)
                code.extend([u"for i in {} loop".format(range_str),
                             u"Put(Character'Val({st}(i)));"
                             .format(st=string),
                             u"end loop;"])
            else:
                code.append("Put({});".format(string))
    elif type_kind in ('IntegerType', 'RealType',
                       'BooleanType', 'Integer32Type'):
        code, string, local = expression(param)
        if type_kind == 'IntegerType':
            cast = "Asn1Int"
        elif type_kind == 'Integer32Type':
            cast = "Integer"
        elif type_kind == 'RealType':
            cast = 'Long_Float'
        elif type_kind == 'BooleanType':
            cast = 'Boolean'
        code.append(u"Put({cast}'Image({s}));".format(cast=cast, s=string))
    elif type_kind == 'EnumeratedType':
        code, string, local = expression(param)
        code.append(u"Put({}'Image({}));".format(type_name(param.exprType),
                                                 string))
    else:
        error = (u'Unsupported parameter in write call ' +
                param.inputString)
        LOG.error(error)
        raise TypeError(error)
    if newline:
        code.append(u"New_Line;")
    return code, string, local


@generate.register(ogAST.Output)
@generate.register(ogAST.ProcedureCall)
def _call_external_function(output, **kwargs):
    ''' Generate the code of a set of output or procedure call statement '''
    code = []
    local_decl = []

    # Add the traceability information
    code.extend(traceability(output))

    for out in output.output:
        signal_name = out['outputName']