Expr Ast_Import::_parse_in( ParsingContext &context ) const {
return context.ret_error( "TODO: _parse_in", false, __FILE__, __LINE__ );
}
Expr Ast_While::_parse_in( ParsingContext &context ) const {
// watch modified variables
IpSnapshot nsv( ip->ip_snapshot );
// we repeat until there are no external modified values
int ne = ip->error_list.size();
std::map<Expr,Expr> unknowns;
for( unsigned old_nsv_size = 0, cpt = 0; ; old_nsv_size = nsv.rooms.size(), ++cpt ) {
if ( cpt == 20 )
return context.ret_error( "infinite loop during while parsing" );
ParsingContext wh_scope( &context, 0, "while_" + to_string( ok ) );
wh_scope.cont = true;
ok->parse_in( wh_scope );
if ( ne != ip->error_list.size() )
return Expr();
// if no new modified variables
if ( old_nsv_size == nsv.rooms.size() )
break;
// replace each modified variable to a new unknown variables
// (to avoid simplifications during the next round)
for( std::pair<Inst *const,Expr> &it : nsv.rooms ) {
Expr unk = unknown_inst( it.second->type(), cpt );
unknowns[ it.first ] = unk;
const_cast<Inst *>( it.first )->set( unk, true );
}
nsv.undo_parsing_contexts();
}
// corr table (output number -> input number)
// -> find if Unknown inst are used to compute the outputs
++Inst::cur_op_id;
for( std::pair<Inst *const,Expr> &it : nsv.rooms )
const_cast<Inst *>( it.first )->get( context.cond )->mark_children();
int cpt = 0;
Vec<int> corr;
Vec<Type *> inp_types;
for( std::pair<Inst *const,Expr> &it : nsv.rooms ) {
if ( unknowns[ it.first ]->op_id == Inst::cur_op_id ) {
corr << cpt++;
inp_types << it.second->type();
} else
corr << -1;
}
// prepare a while inp (for initial values of variables modified in the loop)
Expr winp = while_inp( inp_types );
// set winp[...] as initial values of modified variables
cpt = 0;
for( std::pair<Inst *const,Expr> &it : nsv.rooms ) {
int num_inp = corr[ cpt++ ];
if ( num_inp >= 0 )
const_cast<Inst *>( it.first )->set( get_nout( winp, num_inp ), true );
else
const_cast<Inst *>( it.first )->set( it.second, true );
}
nsv.undo_parsing_contexts();
// relaunch the while inst
ParsingContext wh_scope( &context, 0, "while_" + to_string( ok ) );
wh_scope.cont = true;
ok->parse_in( wh_scope );
if ( wh_scope.cont->always( false ) ) {
ip->ip_snapshot = nsv.prev;
} else {
// make the while instruction
Vec<Expr> out_exprs;
for( std::pair<Inst *const,Expr> &it : nsv.rooms )
out_exprs << const_cast<Inst *>( it.first )->get( context.cond );
Expr wout = while_out( out_exprs, wh_scope.cont );
cpt = 0;
Vec<Expr> inp_exprs;
for( std::pair<Inst *const,Expr> &it : nsv.rooms )
if ( corr[ cpt++ ] >= 0 )
inp_exprs << it.second->simplified( context.cond );
Expr wins = while_inst( inp_exprs, winp, wout, corr );
ip->ip_snapshot = nsv.prev;
// replace changed variable by while_inst outputs
cpt = 0;
for( std::pair<Inst *const,Expr> &it : nsv.rooms )
const_cast<Inst *>( it.first )->set( get_nout( wins, cpt++ ), context.cond );
}
// break(s) to transmit ?
for( ParsingContext::RemBreak rb : wh_scope.rem_breaks )
context.BREAK( rb.count, rb.cond );
return ip->void_var();
}