source: src/Tuples/Explode.cc@ 982ed5b

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Explode.cc --
//
// Author           : Rob Schluntz
// Created On       : Wed Nov 9 13:12:24 2016
// Last Modified By : Rob Schluntz
// Last Modified On : Wed Nov 9 13:20:24 2016
// Update Count     : 2
//

#include "Explode.h"
#include "SynTree/Mutator.h"

namespace Tuples {
        namespace {
                struct AddrExploder : public Mutator {
                        bool foundUniqueExpr = false;
                        Expression * applyAddr( Expression * expr, bool first = true ) {
                                if ( TupleExpr * tupleExpr = dynamic_cast< TupleExpr * >( expr ) ){
                                        foundUniqueExpr = true;
                                        std::list< Expression * > exprs;
                                        for ( Expression *& expr : tupleExpr->get_exprs() ) {
                                                // move & into tuple exprs
                                                exprs.push_back( applyAddr( expr, false ) );
                                        }
                                        // want the top-level expression to be address-taken, but not nested
                                        // tuple expressions
                                        if ( first ) {
                                                return new AddressExpr( new TupleExpr( exprs ) );
                                        } else {
                                                return new TupleExpr( exprs );
                                        }
                                }
                                // anything else should be address-taken as normal
                                return new AddressExpr( expr->clone() );
                        }

                        virtual Expression * mutate( UniqueExpr * uniqueExpr ) {
                                // move & into unique expr so that the unique expr has type T* rather than
                                // type T. In particular, this transformation helps with generating the
                                // correct code for address-taken member tuple expressions, since the result
                                // should now be a tuple of addresses rather than the address of a tuple.
                                // Still, this code is a bit awkward, and could use some improvement.
                                if ( dynamic_cast< AddressExpr * > ( uniqueExpr->get_expr() ) ) {
                                        // this unique expression has already been mutated or otherwise shouldn't be (can't take the address-of an address-of expression)
                                        return uniqueExpr;
                                }
                                UniqueExpr * newUniqueExpr = new UniqueExpr( applyAddr( uniqueExpr->get_expr() ), uniqueExpr->get_id() );
                                delete uniqueExpr;
                                UntypedExpr * deref = UntypedExpr::createDeref( Mutator::mutate( newUniqueExpr ) );
                                return deref;
                        }

                        virtual Expression * mutate( TupleIndexExpr * tupleExpr ) {
                                // tuple index expr needs to be rebuilt to ensure that the type of the
                                // field is consistent with the type of the tuple expr, since the field
                                // may have changed from type T to T*.
                                Expression * expr = tupleExpr->get_tuple()->acceptMutator( *this );
                                tupleExpr->set_tuple( nullptr );
                                TupleIndexExpr * ret = new TupleIndexExpr( expr, tupleExpr->get_index() );
                                delete tupleExpr;
                                return ret;
                        }
                };
        } // namespace

        Expression * distributeAddr( Expression * expr ) {
                AddrExploder addrExploder;
                expr = expr->acceptMutator( addrExploder );
                if ( ! addrExploder.foundUniqueExpr ) {
                        expr = new AddressExpr( expr );
                }
                return expr;
        }
} // namespace Tuples

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //