source: src/CodeGen/CodeGenerator.cc @ 49148d5

//
// 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.
//
// CodeGenerator.cc --
//
// Author           : Richard C. Bilson
// Created On       : Mon May 18 07:44:20 2015
// Last Modified By : Andrew Beach
// Last Modified On : Thu Jun  8 16:00:00 2017
// Update Count     : 485
//

#include <algorithm>
#include <iostream>
#include <cassert>
#include <list>

#include "Parser/ParseNode.h"

#include "SynTree/Declaration.h"
#include "SynTree/Expression.h"
#include "SynTree/Initializer.h"
#include "SynTree/Statement.h"
#include "SynTree/Type.h"
#include "SynTree/Attribute.h"

#include "Common/utility.h"
#include "Common/UnimplementedError.h"

#include "CodeGenerator.h"
#include "OperatorTable.h"
#include "GenType.h"

#include "InitTweak/InitTweak.h"

using namespace std;

namespace CodeGen {
        int CodeGenerator::tabsize = 4;

        // the kinds of statements that would ideally be followed by whitespace
        bool wantSpacing( Statement * stmt) {
                return dynamic_cast< IfStmt * >( stmt ) || dynamic_cast< CompoundStmt * >( stmt ) ||
                        dynamic_cast< WhileStmt * >( stmt ) || dynamic_cast< ForStmt * >( stmt ) || dynamic_cast< SwitchStmt *>( stmt );
        }

        void CodeGenerator::extension( Expression * expr ) {
                if ( expr->get_extension() ) {
                        output << "__extension__ ";
                } // if
        } // extension

        void CodeGenerator::extension( Declaration * decl ) {
                if ( decl->get_extension() ) {
                        output << "__extension__ ";
                } // if
        } // extension

        void CodeGenerator::asmName( DeclarationWithType * decl ) {
                if ( ConstantExpr * asmName = decl->get_asmName() ) {
                        output << " asm ( " << asmName->get_constant()->get_value() << " )";
                } // if
        } // extension

        CodeGenerator::LabelPrinter & CodeGenerator::LabelPrinter::operator()( std::list< Label > & l ) {
                labels = &l;
                return *this;
        }

        ostream & operator<<( ostream & output, CodeGenerator::LabelPrinter & printLabels ) {
                std::list< Label > & labs = *printLabels.labels;
                // l.unique(); // assumes a sorted list. Why not use set? Does order matter?
                for ( Label & l : labs ) {
                        output << l.get_name() + ": ";
                        printLabels.cg.genAttributes( l.get_attributes() );
                } // for
                return output;
        }

        CodeGenerator::LineMarker::LineMarker(
                        CodeLocation const & loc, bool toPrint) :
                loc(loc), toPrint(toPrint)
        {}

        CodeGenerator::LineMarker CodeGenerator::lineDirective(
                        BaseSyntaxNode const * node) {
                return LineMarker(node->location, lineMarks);
        }

        std::ostream & operator<<(std::ostream & out,
                        CodeGenerator::LineMarker const & marker) {
                if (marker.toPrint && marker.loc.isSet()) {
                        return out << "\n# " << marker.loc.linenumber << " \""
                                << marker.loc.filename << "\"\n";
                } else if (marker.toPrint) {
                        return out << "\n/* Missing CodeLocation */\n";
                } else {
                return out;
                }
        }

        CodeGenerator::CodeGenerator( std::ostream & os, bool pretty, bool genC, bool lineMarks ) : indent( CodeGenerator::tabsize ), insideFunction( false ), output( os ), printLabels( *this ), pretty( pretty ), genC( genC ), lineMarks( lineMarks ) {}

        string CodeGenerator::mangleName( DeclarationWithType * decl ) {
                if ( pretty ) return decl->get_name();
                if ( decl->get_mangleName() != "" ) {
                        // need to incorporate scope level in order to differentiate names for destructors
                        return decl->get_scopedMangleName();
                } else {
                        return decl->get_name();
                } // if
        }

        void CodeGenerator::genAttributes( list< Attribute * > & attributes ) {
          if ( attributes.empty() ) return;
                output << "__attribute__ ((";
                for ( list< Attribute * >::iterator attr( attributes.begin() );; ) {
                        output << (*attr)->get_name();
                        if ( ! (*attr)->get_parameters().empty() ) {
                                output << "(";
                                genCommaList( (*attr)->get_parameters().begin(), (*attr)->get_parameters().end() );
                                output << ")";
                        } // if
                  if ( ++attr == attributes.end() ) break;
                        output << ",";                                                          // separator
                } // for
                output << ")) ";
        } // CodeGenerator::genAttributes


        // *** Declarations
        void CodeGenerator::visit( FunctionDecl * functionDecl ) {
                extension( functionDecl );
                genAttributes( functionDecl->get_attributes() );

                handleStorageClass( functionDecl );
                functionDecl->get_funcSpec().print( output );

                output << genType( functionDecl->get_functionType(), mangleName( functionDecl ), pretty, genC );

                asmName( functionDecl );

                // acceptAll( functionDecl->get_oldDecls(), *this );
                if ( functionDecl->get_statements() ) {
                        functionDecl->get_statements()->accept( *this );
                } // if
        }

        void CodeGenerator::visit( ObjectDecl * objectDecl ) {
                if (objectDecl->get_name().empty() && genC ) {
                        // only generate an anonymous name when generating C code, otherwise it clutters the output too much
                        static UniqueName name = { "__anonymous_object" };
                        objectDecl->set_name( name.newName() );
                }

                extension( objectDecl );
                genAttributes( objectDecl->get_attributes() );

                handleStorageClass( objectDecl );
                output << genType( objectDecl->get_type(), mangleName( objectDecl ), pretty, genC );

                asmName( objectDecl );

                if ( objectDecl->get_init() ) {
                        output << " = ";
                        objectDecl->get_init()->accept( *this );
                } // if

                if ( objectDecl->get_bitfieldWidth() ) {
                        output << ":";
                        objectDecl->get_bitfieldWidth()->accept( *this );
                } // if
        }

        void CodeGenerator::handleAggregate( AggregateDecl * aggDecl, const std::string & kind ) {
                genAttributes( aggDecl->get_attributes() );

                if( ! aggDecl->get_parameters().empty() && ! genC ) {
                        // assertf( ! genC, "Aggregate type parameters should not reach code generation." );
                        output << "forall(";
                        genCommaList( aggDecl->get_parameters().begin(), aggDecl->get_parameters().end() );
                        output << ")" << endl;
                }

                output << kind;
                if ( aggDecl->get_name() != "" )
                        output << aggDecl->get_name();

                if ( aggDecl->has_body() ) {
                        std::list< Declaration * > & memb = aggDecl->get_members();
                        output << " {" << endl;

                        ++indent;
                        for ( std::list< Declaration* >::iterator i = memb.begin(); i != memb.end(); i++ ) {
                                output << lineDirective( *i ) << indent;
                                (*i)->accept( *this );
                                output << ";" << endl;
                        } // for

                        --indent;

                        output << indent << "}";
                } // if
        }

        void CodeGenerator::visit( StructDecl * structDecl ) {
                extension( structDecl );
                handleAggregate( structDecl, "struct " );
        }

        void CodeGenerator::visit( UnionDecl * unionDecl ) {
                extension( unionDecl );
                handleAggregate( unionDecl, "union " );
        }

        void CodeGenerator::visit( EnumDecl * enumDecl ) {
                extension( enumDecl );
                output << lineDirective ( enumDecl );
                output << "enum ";
                genAttributes( enumDecl->get_attributes() );

                if ( enumDecl->get_name() != "" )
                        output << enumDecl->get_name();

                std::list< Declaration* > &memb = enumDecl->get_members();

                if ( ! memb.empty() ) {
                        output << " {" << endl;

                        ++indent;
                        for ( std::list< Declaration* >::iterator i = memb.begin(); i != memb.end();  i++) {
                                ObjectDecl * obj = dynamic_cast< ObjectDecl* >( *i );
                                assert( obj );
                                output << lineDirective( obj ) << indent << mangleName( obj );
                                if ( obj->get_init() ) {
                                        output << " = ";
                                        obj->get_init()->accept( *this );
                                } // if
                                output << "," << endl;
                        } // for

                        --indent;

                        output << indent << "}";
                } // if
        }

        void CodeGenerator::visit( __attribute__((unused)) TraitDecl * traitDecl ) {}

        void CodeGenerator::visit( TypedefDecl * typeDecl ) {
                assertf( ! genC, "Typedefs are removed and substituted in earlier passes." );
                output << lineDirective( typeDecl );
                output << "typedef ";
                output << genType( typeDecl->get_base(), typeDecl->get_name(), pretty, genC ) << endl;
        }

        void CodeGenerator::visit( TypeDecl * typeDecl ) {
                if ( genC ) {
                        // really, we should mutate this into something that isn't a TypeDecl but that requires large-scale changes,
                        // still to be done
                        extension( typeDecl );
                        output << "extern unsigned long " << typeDecl->get_name();
                        if ( typeDecl->get_base() ) {
                                output << " = sizeof( " << genType( typeDecl->get_base(), "", pretty, genC ) << " )";
                        } // if
                } else {
                        output << typeDecl->genTypeString() << " " << typeDecl->get_name();
                        if ( typeDecl->get_kind() != TypeDecl::Any && typeDecl->get_sized() ) {
                                output << " | sized(" << typeDecl->get_name() << ")";
                        }
                        if ( ! typeDecl->get_assertions().empty() ) {
                                output << " | { ";
                                genCommaList( typeDecl->get_assertions().begin(), typeDecl->get_assertions().end() );
                                output << " }";
                        }
                }
        }

        void CodeGenerator::visit( Designation * designation ) {
                std::list< Expression * > designators = designation->get_designators();
                if ( designators.size() == 0 ) return;
                for ( Expression * des : designators ) {
                        if ( dynamic_cast< NameExpr * >( des ) || dynamic_cast< VariableExpr * >( des ) ) {
                                // if expression is a NameExpr or VariableExpr, then initializing aggregate member
                                output << ".";
                                des->accept( *this );
                        } else {
                                // otherwise, it has to be a ConstantExpr or CastExpr, initializing array eleemnt
                                output << "[";
                                des->accept( *this );
                                output << "]";
                        } // if
                } // for
                output << " = ";
        }

        void CodeGenerator::visit( SingleInit * init ) {
                init->get_value()->accept( *this );
        }

        void CodeGenerator::visit( ListInit * init ) {
                auto initBegin = init->begin();
                auto initEnd = init->end();
                auto desigBegin = init->get_designations().begin();
                auto desigEnd = init->get_designations().end();

                output << "{ ";
                for ( ; initBegin != initEnd && desigBegin != desigEnd; ) {
                        (*desigBegin)->accept( *this );
                        (*initBegin)->accept( *this );
                        ++initBegin, ++desigBegin;
                        if ( initBegin != initEnd ) {
                                output << ", ";
                        }
                }
                output << " }";
                assertf( initBegin == initEnd && desigBegin == desigEnd, "Initializers and designators not the same length. %s", toString( init ).c_str() );
        }

        void CodeGenerator::visit( __attribute__((unused)) ConstructorInit * init ){
                assertf( ! genC, "ConstructorInit nodes should not reach code generation." );
                // xxx - generate something reasonable for constructor/destructor pairs
                output << "<ctorinit>";
        }

        void CodeGenerator::visit( Constant * constant ) {
                output << constant->get_value() ;
        }

        // *** Expressions
        void CodeGenerator::visit( ApplicationExpr * applicationExpr ) {
                extension( applicationExpr );
                if ( VariableExpr * varExpr = dynamic_cast< VariableExpr* >( applicationExpr->get_function() ) ) {
                        OperatorInfo opInfo;
                        if ( varExpr->get_var()->get_linkage() == LinkageSpec::Intrinsic && operatorLookup( varExpr->get_var()->get_name(), opInfo ) ) {
                                std::list< Expression* >::iterator arg = applicationExpr->get_args().begin();
                                switch ( opInfo.type ) {
                                  case OT_PREFIXASSIGN:
                                  case OT_POSTFIXASSIGN:
                                  case OT_INFIXASSIGN:
                                  case OT_CTOR:
                                  case OT_DTOR:
                                        {
                                                assert( arg != applicationExpr->get_args().end() );
                                                if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( *arg ) ) {
                                                        // remove & from first assignment/ctor argument
                                                        *arg = addrExpr->get_arg();
                                                } else {
                                                        // no address-of operator, so must be a pointer - add dereference
                                                        // NOTE: if the assertion starts to trigger, check that the application expr isn't being shared.
                                                        // Since its arguments are modified here, this assertion most commonly triggers when the application
                                                        // is visited multiple times.
                                                        UntypedExpr * newExpr = new UntypedExpr( new NameExpr( "*?" ) );
                                                        newExpr->get_args().push_back( *arg );
                                                        Type * type = InitTweak::getPointerBase( (*arg)->get_result() );
                                                        assertf( type, "First argument to a derefence must be a pointer. Ensure that expressions are not being shared." );
                                                        newExpr->set_result( type->clone() );
                                                        *arg = newExpr;
                                                } // if
                                                break;
                                        }

                                  default:
                                        // do nothing
                                        ;
                                } // switch

                                switch ( opInfo.type ) {
                                  case OT_INDEX:
                                        assert( applicationExpr->get_args().size() == 2 );
                                        (*arg++)->accept( *this );
                                        output << "[";
                                        (*arg)->accept( *this );
                                        output << "]";
                                        break;

                                  case OT_CALL:
                                        // there are no intrinsic definitions of the function call operator
                                        assert( false );
                                        break;

                                  case OT_CTOR:
                                  case OT_DTOR:
                                        if ( applicationExpr->get_args().size() == 1 ) {
                                                // the expression fed into a single parameter constructor or destructor may contain side
                                                // effects, so must still output this expression
                                                output << "(";
                                                (*arg++)->accept( *this );
                                                output << ") /* " << opInfo.inputName << " */";
                                        } else if ( applicationExpr->get_args().size() == 2 ) {
                                                // intrinsic two parameter constructors are essentially bitwise assignment
                                                output << "(";
                                                (*arg++)->accept( *this );
                                                output << opInfo.symbol;
                                                (*arg)->accept( *this );
                                                output << ") /* " << opInfo.inputName << " */";
                                        } else {
                                                // no constructors with 0 or more than 2 parameters
                                                assert( false );
                                        } // if
                                        break;

                                  case OT_PREFIX:
                                  case OT_PREFIXASSIGN:
                                        assert( applicationExpr->get_args().size() == 1 );
                                        output << "(";
                                        output << opInfo.symbol;
                                        (*arg)->accept( *this );
                                        output << ")";
                                        break;

                                  case OT_POSTFIX:
                                  case OT_POSTFIXASSIGN:
                                        assert( applicationExpr->get_args().size() == 1 );
                                        (*arg)->accept( *this );
                                        output << opInfo.symbol;
                                        break;


                                  case OT_INFIX:
                                  case OT_INFIXASSIGN:
                                        assert( applicationExpr->get_args().size() == 2 );
                                        output << "(";
                                        (*arg++)->accept( *this );
                                        output << opInfo.symbol;
                                        (*arg)->accept( *this );
                                        output << ")";
                                        break;

                                  case OT_CONSTANT:
                                  case OT_LABELADDRESS:
                                        // there are no intrinsic definitions of 0/1 or label addresses as functions
                                        assert( false );
                                } // switch
                        } else {
                                varExpr->accept( *this );
                                output << "(";
                                genCommaList( applicationExpr->get_args().begin(), applicationExpr->get_args().end() );
                                output << ")";
                        } // if
                } else {
                        applicationExpr->get_function()->accept( *this );
                        output << "(";
                        genCommaList( applicationExpr->get_args().begin(), applicationExpr->get_args().end() );
                        output << ")";
                } // if
        }

        void CodeGenerator::visit( UntypedExpr * untypedExpr ) {
                extension( untypedExpr );
                if ( NameExpr * nameExpr = dynamic_cast< NameExpr* >( untypedExpr->get_function() ) ) {
                        OperatorInfo opInfo;
                        if ( operatorLookup( nameExpr->get_name(), opInfo ) ) {
                                std::list< Expression* >::iterator arg = untypedExpr->get_args().begin();
                                switch ( opInfo.type ) {
                                  case OT_INDEX:
                                        assert( untypedExpr->get_args().size() == 2 );
                                        (*arg++)->accept( *this );
                                        output << "[";
                                        (*arg)->accept( *this );
                                        output << "]";
                                        break;

                                  case OT_CALL:
                                        assert( false );

                                  case OT_CTOR:
                                  case OT_DTOR:
                                        if ( untypedExpr->get_args().size() == 1 ) {
                                                // the expression fed into a single parameter constructor or destructor may contain side
                                                // effects, so must still output this expression
                                                output << "(";
                                                (*arg++)->accept( *this );
                                                output << ") /* " << opInfo.inputName << " */";
                                        } else if ( untypedExpr->get_args().size() == 2 ) {
                                                // intrinsic two parameter constructors are essentially bitwise assignment
                                                output << "(";
                                                (*arg++)->accept( *this );
                                                output << opInfo.symbol;
                                                (*arg)->accept( *this );
                                                output << ") /* " << opInfo.inputName << " */";
                                        } else {
                                                // no constructors with 0 or more than 2 parameters
                                                assert( false );
                                        } // if
                                        break;

                                  case OT_PREFIX:
                                  case OT_PREFIXASSIGN:
                                  case OT_LABELADDRESS:
                                        assert( untypedExpr->get_args().size() == 1 );
                                        output << "(";
                                        output << opInfo.symbol;
                                        (*arg)->accept( *this );
                                        output << ")";
                                        break;

                                  case OT_POSTFIX:
                                  case OT_POSTFIXASSIGN:
                                        assert( untypedExpr->get_args().size() == 1 );
                                        (*arg)->accept( *this );
                                        output << opInfo.symbol;
                                        break;

                                  case OT_INFIX:
                                  case OT_INFIXASSIGN:
                                        assert( untypedExpr->get_args().size() == 2 );
                                        output << "(";
                                        (*arg++)->accept( *this );
                                        output << opInfo.symbol;
                                        (*arg)->accept( *this );
                                        output << ")";
                                        break;

                                  case OT_CONSTANT:
                                        // there are no intrinsic definitions of 0 or 1 as functions
                                        assert( false );
                                } // switch
                        } else {
                                if ( nameExpr->get_name() == "..." ) { // case V1 ... V2 or case V1~V2
                                        assert( untypedExpr->get_args().size() == 2 );
                                        (*untypedExpr->get_args().begin())->accept( *this );
                                        output << " ... ";
                                        (*--untypedExpr->get_args().end())->accept( *this );
                                } else {                                                                // builtin routines
                                        nameExpr->accept( *this );
                                        output << "(";
                                        genCommaList( untypedExpr->get_args().begin(), untypedExpr->get_args().end() );
                                        output << ")";
                                } // if
                        } // if
                } else {
                        untypedExpr->get_function()->accept( *this );
                        output << "(";
                        genCommaList( untypedExpr->get_args().begin(), untypedExpr->get_args().end() );
                        output << ")";
                } // if
        }

        void CodeGenerator::visit( RangeExpr * rangeExpr ) {
                rangeExpr->get_low()->accept( *this );
                output << " ... ";
                rangeExpr->get_high()->accept( *this );
        }

        void CodeGenerator::visit( NameExpr * nameExpr ) {
                extension( nameExpr );
                OperatorInfo opInfo;
                if ( operatorLookup( nameExpr->get_name(), opInfo ) ) {
                        assert( opInfo.type == OT_CONSTANT );
                        output << opInfo.symbol;
                } else {
                        output << nameExpr->get_name();
                } // if
        }

        void CodeGenerator::visit( AddressExpr * addressExpr ) {
                extension( addressExpr );
                output << "(&";
                // this hack makes sure that we don't convert "constant_zero" to "0" if we're taking its address
                if ( VariableExpr * variableExpr = dynamic_cast< VariableExpr* >( addressExpr->get_arg() ) ) {
                        output << mangleName( variableExpr->get_var() );
                } else {
                        addressExpr->get_arg()->accept( *this );
                } // if
                output << ")";
        }

        void CodeGenerator::visit( CastExpr * castExpr ) {
                extension( castExpr );
                output << "(";
                if ( castExpr->get_result()->isVoid() ) {
                        output << "(void)" ;
                } else if ( ! castExpr->get_result()->get_lvalue() ) {
                        // at least one result type of cast, but not an lvalue
                        output << "(";
                        output << genType( castExpr->get_result(), "", pretty, genC );
                        output << ")";
                } else {
                        // otherwise, the cast is to an lvalue type, so the cast should be dropped, since the result of a cast is
                        // never an lvalue in C
                } // if
                castExpr->get_arg()->accept( *this );
                output << ")";
        }

        void CodeGenerator::visit( UntypedMemberExpr * memberExpr ) {
                assertf( ! genC, "UntypedMemberExpr should not reach code generation." );
                extension( memberExpr );
                memberExpr->get_aggregate()->accept( *this );
                output << ".";
                memberExpr->get_member()->accept( *this );
        }

        void CodeGenerator::visit( MemberExpr * memberExpr ) {
                extension( memberExpr );
                memberExpr->get_aggregate()->accept( *this );
                output << "." << mangleName( memberExpr->get_member() );
        }

        void CodeGenerator::visit( VariableExpr * variableExpr ) {
                extension( variableExpr );
                OperatorInfo opInfo;
                if ( variableExpr->get_var()->get_linkage() == LinkageSpec::Intrinsic && operatorLookup( variableExpr->get_var()->get_name(), opInfo ) && opInfo.type == OT_CONSTANT ) {
                        output << opInfo.symbol;
                } else {
                        output << mangleName( variableExpr->get_var() );
                } // if
        }

        void CodeGenerator::visit( ConstantExpr * constantExpr ) {
                assert( constantExpr->get_constant() );
                extension( constantExpr );
                constantExpr->get_constant()->accept( *this );
        }

        void CodeGenerator::visit( SizeofExpr * sizeofExpr ) {
                extension( sizeofExpr );
                output << "sizeof(";
                if ( sizeofExpr->get_isType() ) {
                        output << genType( sizeofExpr->get_type(), "", pretty, genC );
                } else {
                        sizeofExpr->get_expr()->accept( *this );
                } // if
                output << ")";
        }

        void CodeGenerator::visit( AlignofExpr * alignofExpr ) {
                // use GCC extension to avoid bumping std to C11
                extension( alignofExpr );
                output << "__alignof__(";
                if ( alignofExpr->get_isType() ) {
                        output << genType( alignofExpr->get_type(), "", pretty, genC );
                } else {
                        alignofExpr->get_expr()->accept( *this );
                } // if
                output << ")";
        }

        void CodeGenerator::visit( UntypedOffsetofExpr * offsetofExpr ) {
                assertf( ! genC, "UntypedOffsetofExpr should not reach code generation." );
                output << "offsetof(";
                output << genType( offsetofExpr->get_type(), "", pretty, genC );
                output << ", " << offsetofExpr->get_member();
                output << ")";
        }

        void CodeGenerator::visit( OffsetofExpr * offsetofExpr ) {
                // use GCC builtin
                output << "__builtin_offsetof(";
                output << genType( offsetofExpr->get_type(), "", pretty, genC );
                output << ", " << mangleName( offsetofExpr->get_member() );
                output << ")";
        }

        void CodeGenerator::visit( OffsetPackExpr * offsetPackExpr ) {
                assertf( ! genC, "OffsetPackExpr should not reach code generation." );
                output << "__CFA_offsetpack(" << genType( offsetPackExpr->get_type(), "", pretty, genC ) << ")";
        }

        void CodeGenerator::visit( LogicalExpr * logicalExpr ) {
                extension( logicalExpr );
                output << "(";
                logicalExpr->get_arg1()->accept( *this );
                if ( logicalExpr->get_isAnd() ) {
                        output << " && ";
                } else {
                        output << " || ";
                } // if
                logicalExpr->get_arg2()->accept( *this );
                output << ")";
        }

        void CodeGenerator::visit( ConditionalExpr * conditionalExpr ) {
                extension( conditionalExpr );
                output << "(";
                conditionalExpr->get_arg1()->accept( *this );
                output << " ? ";
                conditionalExpr->get_arg2()->accept( *this );
                output << " : ";
                conditionalExpr->get_arg3()->accept( *this );
                output << ")";
        }

        void CodeGenerator::visit( CommaExpr * commaExpr ) {
                extension( commaExpr );
                output << "(";
                commaExpr->get_arg1()->accept( *this );
                output << " , ";
                commaExpr->get_arg2()->accept( *this );
                output << ")";
        }

        void CodeGenerator::visit( UntypedTupleExpr * tupleExpr ) {
                assertf( ! genC, "UntypedTupleExpr should not reach code generation." );
                extension( tupleExpr );
                output << "[";
                genCommaList( tupleExpr->get_exprs().begin(), tupleExpr->get_exprs().end() );
                output << "]";
        }

        void CodeGenerator::visit( TupleExpr * tupleExpr ) {
                assertf( ! genC, "TupleExpr should not reach code generation." );
                extension( tupleExpr );
                output << "[";
                genCommaList( tupleExpr->get_exprs().begin(), tupleExpr->get_exprs().end() );
                output << "]";
        }

        void CodeGenerator::visit( TupleIndexExpr * tupleExpr ) {
                assertf( ! genC, "TupleIndexExpr should not reach code generation." );
                extension( tupleExpr );
                tupleExpr->get_tuple()->accept( *this );
                output << "." << tupleExpr->get_index();
        }

        void CodeGenerator::visit( TypeExpr * typeExpr ) {
                // if ( genC ) std::cerr << "typeexpr still exists: " << typeExpr << std::endl;
                // assertf( ! genC, "TypeExpr should not reach code generation." );
                if ( ! genC ) {
                        output<< genType( typeExpr->get_type(), "", pretty, genC );
                }
        }

        void CodeGenerator::visit( AsmExpr * asmExpr ) {
                if ( asmExpr->get_inout() ) {
                        output << "[ ";
                        asmExpr->get_inout()->accept( *this );
                        output << " ] ";
                } // if
                asmExpr->get_constraint()->accept( *this );
                output << " ( ";
                asmExpr->get_operand()->accept( *this );
                output << " )";
        }

        void CodeGenerator::visit( CompoundLiteralExpr *compLitExpr ) {
                assert( compLitExpr->get_result() && dynamic_cast< ListInit * > ( compLitExpr->get_initializer() ) );
                output << "(" << genType( compLitExpr->get_result(), "", pretty, genC ) << ")";
                compLitExpr->get_initializer()->accept( *this );
        }

        void CodeGenerator::visit( StmtExpr * stmtExpr ) {
                std::list< Statement * > & stmts = stmtExpr->get_statements()->get_kids();
                output << lineDirective( stmtExpr) << "({" << std::endl;
                ++indent;
                unsigned int numStmts = stmts.size();
                unsigned int i = 0;
                for ( Statement * stmt : stmts ) {
                        output << lineDirective( stmt ) << indent;
            output << printLabels( stmt->get_labels() );
                        if ( i+1 == numStmts ) {
                                // last statement in a statement expression needs to be handled specially -
                                // cannot cast to void, otherwise the expression statement has no value
                                if ( ExprStmt * exprStmt = dynamic_cast< ExprStmt * >( stmt ) ) {
                                        exprStmt->get_expr()->accept( *this );
                                        output << ";" << endl;
                                        ++i;
                                        break;
                                }
                        }
                        stmt->accept( *this );
                        output << endl;
                        if ( wantSpacing( stmt ) ) {
                                output << endl;
                        } // if
                        ++i;
                }
                --indent;
                output << indent << "})";
        }

        // *** Statements
        void CodeGenerator::visit( CompoundStmt * compoundStmt ) {
                std::list<Statement*> ks = compoundStmt->get_kids();
                output << "{" << endl;

                ++indent;

                for ( std::list<Statement *>::iterator i = ks.begin(); i != ks.end();  i++ ) {
                        output << indent << printLabels( (*i)->get_labels() );
                        (*i)->accept( *this );

                        output << endl;
                        if ( wantSpacing( *i ) ) {
                                output << endl;
                        } // if
                } // for
                --indent;

                output << indent << "}";
        }

        void CodeGenerator::visit( ExprStmt * exprStmt ) {
                assert( exprStmt );
                Expression * expr = exprStmt->get_expr();
                if ( genC ) {
                        // cast the top-level expression to void to reduce gcc warnings.
                        expr = new CastExpr( expr );
                }
                expr->accept( *this );
                output << ";";
        }

        void CodeGenerator::visit( AsmStmt * asmStmt ) {
                output << "asm ";
                if ( asmStmt->get_voltile() ) output << "volatile ";
                if ( ! asmStmt->get_gotolabels().empty()  ) output << "goto ";
                output << "( ";
                if ( asmStmt->get_instruction() ) asmStmt->get_instruction()->accept( *this );
                output << " : ";
                genCommaList( asmStmt->get_output().begin(), asmStmt->get_output().end() );
                output << " : ";
                genCommaList( asmStmt->get_input().begin(), asmStmt->get_input().end() );
                output << " : ";
                genCommaList( asmStmt->get_clobber().begin(), asmStmt->get_clobber().end() );
                if ( ! asmStmt->get_gotolabels().empty() ) {
                        output << " : ";
                        for ( std::list<Label>::iterator begin = asmStmt->get_gotolabels().begin();; ) {
                                output << *begin++;
                                if ( begin == asmStmt->get_gotolabels().end() ) break;
                                output << ", ";
                        } // for
                } // if
                output << " );" ;
        }

        void CodeGenerator::visit( AsmDecl * asmDecl ) {
                output << "asm ";
                AsmStmt * asmStmt = asmDecl->get_stmt();
                output << "( ";
                if ( asmStmt->get_instruction() ) asmStmt->get_instruction()->accept( *this );
                output << " )" ;
        }

        void CodeGenerator::visit( IfStmt * ifStmt ) {
                output << lineDirective( ifStmt );
                output << "if ( ";
                ifStmt->get_condition()->accept( *this );
                output << " ) ";

                ifStmt->get_thenPart()->accept( *this );

                if ( ifStmt->get_elsePart() != 0) {
                        output << " else ";
                        ifStmt->get_elsePart()->accept( *this );
                } // if
        }

        void CodeGenerator::visit( SwitchStmt * switchStmt ) {
                output << lineDirective( switchStmt );
                output << "switch ( " ;
                switchStmt->get_condition()->accept( *this );
                output << " ) ";

                output << "{" << std::endl;
                ++indent;
                acceptAll( switchStmt->get_statements(), *this );
                --indent;
                output << indent << "}";
        }

        void CodeGenerator::visit( CaseStmt * caseStmt ) {
                output << lineDirective( caseStmt );
                output << indent;
                if ( caseStmt->isDefault()) {
                        output << "default";
                } else {
                        output << "case ";
                        caseStmt->get_condition()->accept( *this );
                } // if
                output << ":\n";

                std::list<Statement *> sts = caseStmt->get_statements();

                ++indent;
                for ( std::list<Statement *>::iterator i = sts.begin(); i != sts.end();  i++) {
                        output << indent << printLabels( (*i)->get_labels() )  ;
                        (*i)->accept( *this );
                        output << endl;
                } // for
                --indent;
        }

        void CodeGenerator::visit( BranchStmt * branchStmt ) {
                switch ( branchStmt->get_type()) {
                  case BranchStmt::Goto:
                        if ( ! branchStmt->get_target().empty() )
                                output << "goto " << branchStmt->get_target();
                        else {
                                if ( branchStmt->get_computedTarget() != 0 ) {
                                        output << "goto *";
                                        branchStmt->get_computedTarget()->accept( *this );
                                } // if
                        } // if
                        break;
                  case BranchStmt::Break:
                        output << "break";
                        break;
                  case BranchStmt::Continue:
                        output << "continue";
                        break;
                } // switch
                output << ";";
        }

        void CodeGenerator::visit( ReturnStmt * returnStmt ) {
                output << "return ";
                maybeAccept( returnStmt->get_expr(), *this );
                output << ";";
        }

        void CodeGenerator::visit( ThrowStmt * throwStmt ) {
                assertf( ! genC, "Throw statements should not reach code generation." );

                output << ((throwStmt->get_kind() == ThrowStmt::Terminate) ?
                           "throw" : "throwResume");
                if (throwStmt->get_expr()) {
                        output << " ";
                        throwStmt->get_expr()->accept( *this );
                }
                if (throwStmt->get_target()) {
                        output << " _At ";
                        throwStmt->get_target()->accept( *this );
                }
                output << ";";
        }

        void CodeGenerator::visit( WhileStmt * whileStmt ) {
                if ( whileStmt->get_isDoWhile() ) {
                        output << "do" ;
                } else {
                        output << "while (" ;
                        whileStmt->get_condition()->accept( *this );
                        output << ")";
                } // if
                output << " ";

                output << CodeGenerator::printLabels( whileStmt->get_body()->get_labels() );
                whileStmt->get_body()->accept( *this );

                output << indent;

                if ( whileStmt->get_isDoWhile() ) {
                        output << " while (" ;
                        whileStmt->get_condition()->accept( *this );
                        output << ");";
                } // if
        }

        void CodeGenerator::visit( ForStmt * forStmt ) {
                // initialization is always hoisted, so don't bother doing anything with that
                output << "for (;";

                if ( forStmt->get_condition() != 0 ) {
                        forStmt->get_condition()->accept( *this );
                } // if
                output << ";";

                if ( forStmt->get_increment() != 0 ) {
                        // cast the top-level expression to void to reduce gcc warnings.
                        Expression * expr = new CastExpr( forStmt->get_increment() );
                        expr->accept( *this );
                } // if
                output << ") ";

                if ( forStmt->get_body() != 0 ) {
                        output << CodeGenerator::printLabels( forStmt->get_body()->get_labels() );
                        forStmt->get_body()->accept( *this );
                } // if
        }

        void CodeGenerator::visit( __attribute__((unused)) NullStmt * nullStmt ) {
                //output << indent << CodeGenerator::printLabels( nullStmt->get_labels() );
                output << "/* null statement */ ;";
        }

        void CodeGenerator::visit( DeclStmt * declStmt ) {
                declStmt->get_decl()->accept( *this );

                if ( doSemicolon( declStmt->get_decl() ) ) {
                        output << ";";
                } // if
        }

        void CodeGenerator::handleStorageClass( DeclarationWithType * decl ) {
                if ( decl->get_storageClasses().any() ) {
                        decl->get_storageClasses().print( output );
                } // if
        } // CodeGenerator::handleStorageClass

        std::string genName( DeclarationWithType * decl ) {
                CodeGen::OperatorInfo opInfo;
                if ( operatorLookup( decl->get_name(), opInfo ) ) {
                        return opInfo.outputName;
                } else {
                        return decl->get_name();
                } // if
        }
} // namespace CodeGen

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