source: src/CodeGen/CodeGenerator.cc @ de52331

//
// 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 : Peter A. Buhr
// Last Modified On : Fri Mar 12 19:00:42 2021
// Update Count     : 536
//
#include "CodeGenerator.h"

#include <cassert>                   // for assert, assertf
#include <list>                      // for _List_iterator, list, list<>::it...

#include "Common/UniqueName.h"       // for UniqueName
#include "Common/utility.h"          // for CodeLocation, toString
#include "GenType.h"                 // for genType
#include "InitTweak/InitTweak.h"     // for getPointerBase
#include "OperatorTable.h"           // for OperatorInfo, operatorLookup
#include "SynTree/LinkageSpec.h"     // for Spec, Intrinsic
#include "SynTree/Attribute.h"       // for Attribute
#include "SynTree/BaseSyntaxNode.h"  // for BaseSyntaxNode
#include "SynTree/Constant.h"        // for Constant
#include "SynTree/Declaration.h"     // for DeclarationWithType, TypeDecl
#include "SynTree/Expression.h"      // for Expression, UntypedExpr, Applica...
#include "SynTree/Initializer.h"     // for Initializer, ListInit, Designation
#include "SynTree/Label.h"           // for Label, operator<<
#include "SynTree/Statement.h"       // for Statement, AsmStmt, BranchStmt
#include "SynTree/Type.h"            // for Type, Type::StorageClasses, Func...

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 = dynamic_cast<ConstantExpr *>(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;
        }

        // Using updateLocation at the beginning of a node and endl within a node should become the method of formating.
        void CodeGenerator::updateLocation( CodeLocation const & to ) {
                // skip if linemarks shouldn't appear or if codelocation is unset
                if ( !options.lineMarks || to.isUnset() ) return;

                if ( currentLocation.followedBy( to, 0 ) ) {
                        return;
                } else if ( currentLocation.followedBy( to, 1 ) ) {
                        output << "\n" << indent;
                        currentLocation.first_line += 1;
                } else if ( currentLocation.followedBy( to, 2 ) ) {
                        output << "\n\n" << indent;
                        currentLocation.first_line += 2;
                } else {
                        output << "\n# " << to.first_line << " \"" << to.filename
                                   << "\"\n" << indent;
                        currentLocation = to;
                }
                output << std::flush;
        }

        void CodeGenerator::updateLocation( BaseSyntaxNode const * to ) {
                updateLocation( to->location );
        }

        // replace endl
        ostream & CodeGenerator::LineEnder::operator()( ostream & os ) const {
                // if ( !cg.lineMarks ) {
                //      os << "\n" << cg.indent << std::flush;
                // }
                os << "\n" << std::flush;
                cg.currentLocation.first_line++;
                // os << "/* did endl; current loc is: " << cg.currentLocation.first_line << "*/";
                return os;
        }

        CodeGenerator::CodeGenerator( std::ostream & os, bool pretty, bool genC, bool lineMarks, bool printExprTypes ) : indent( 0, CodeGenerator::tabsize ), output( os ), printLabels( *this ), options( pretty, genC, lineMarks, printExprTypes ), endl( *this ) {}
        CodeGenerator::CodeGenerator( std::ostream & os, const Options &options ) : indent( 0, CodeGenerator::tabsize ), output( os ), printLabels( *this ), options(options), endl( *this ) {}

        string CodeGenerator::mangleName( DeclarationWithType * decl ) {
                // GCC builtins should always be printed unmangled
                if ( options.pretty || decl->linkage.is_gcc_builtin ) return decl->name;
                if ( LinkageSpec::isMangled(decl->linkage) && decl->mangleName != "" ) {
                        // need to incorporate scope level in order to differentiate names for destructors
                        return decl->get_scopedMangleName();
                } else {
                        return decl->name;
                } // if
        }

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

        // *** BaseSyntaxNode
        void CodeGenerator::previsit( BaseSyntaxNode * node ) {
                // turn off automatic recursion for all nodes, to allow each visitor to
                // precisely control the order in which its children are visited.
                visit_children = false;
                updateLocation( node );
        }

        // *** BaseSyntaxNode
        void CodeGenerator::postvisit( BaseSyntaxNode * node ) {
                std::stringstream ss;
                node->print( ss );
                assertf( false, "Unhandled node reached in CodeGenerator: %s", ss.str().c_str() );
        }

        // *** Expression
        void CodeGenerator::previsit( Expression * node ) {
                previsit( (BaseSyntaxNode *)node );
                GuardAction( [this, node](){
                                if ( options.printExprTypes && node->result ) {
                                        output << " /* " << genType( node->result, "", options ) << " */ ";
                                }
                        } );
        }

        // *** Declarations
        void CodeGenerator::postvisit( FunctionDecl * functionDecl ) {
                // deleted decls should never be used, so don't print them
                if ( functionDecl->isDeleted && options.genC ) return;
                extension( functionDecl );
                genAttributes( functionDecl->get_attributes() );

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

                Options subOptions = options;
                subOptions.anonymousUnused = functionDecl->has_body();
                output << genType( functionDecl->get_functionType(), mangleName( functionDecl ), subOptions );

                asmName( functionDecl );

                if ( functionDecl->get_statements() ) {
                        functionDecl->get_statements()->accept( *visitor );
                } // if
                if ( functionDecl->isDeleted ) {
                        output << " = void";
                }
        }

        void CodeGenerator::postvisit( ObjectDecl * objectDecl ) {
                // deleted decls should never be used, so don't print them
                if ( objectDecl->isDeleted && options.genC ) return;

                // gcc allows an empty declarator (no name) for bit-fields and C states: 6.7.2.1 Structure and union specifiers,
                // point 4, page 113: If the (bit field) value is zero, the declaration shall have no declarator.  For anything
                // else, the anonymous name refers to the anonymous object for plan9 inheritance.
                if ( objectDecl->get_name().empty() && options.genC && ! objectDecl->get_bitfieldWidth() ) {
                        // 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() );
                        // Stops unused parameter warnings.
                        if ( options.anonymousUnused ) {
                                objectDecl->attributes.push_back( new Attribute( "unused" ) );
                        }
                }

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

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

                asmName( objectDecl );

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

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

        void CodeGenerator::handleAggregate( AggregateDecl * aggDecl, const std::string & kind ) {
                if( ! aggDecl->parameters.empty() && ! options.genC ) {
                        // assertf( ! genC, "Aggregate type parameters should not reach code generation." );
                        output << "forall(";
                        genCommaList( aggDecl->parameters.begin(), aggDecl->parameters.end() );
                        output << ")" << endl;
                        output << indent;
                }

                output << kind;
                genAttributes( aggDecl->attributes );
                output << aggDecl->name;

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

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

                        --indent;

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

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

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

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

                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 << indent << mangleName( obj );
                                if ( obj->get_init() ) {
                                        output << " = ";
                                        obj->get_init()->accept( *visitor );
                                } // if
                                output << "," << endl;
                        } // for

                        --indent;

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

        void CodeGenerator::postvisit( TraitDecl * traitDecl ) {
                assertf( ! options.genC, "TraitDecls should not reach code generation." );
                extension( traitDecl );
                handleAggregate( traitDecl, "trait " );
        }

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

        void CodeGenerator::postvisit( TypeDecl * typeDecl ) {
                assertf( ! options.genC, "TypeDecls should not reach code generation." );
                output << typeDecl->genTypeString() << " " << typeDecl->name;
                if ( typeDecl->sized ) {
                        output << " | sized(" << typeDecl->name << ")";
                }
                if ( ! typeDecl->assertions.empty() ) {
                        output << " | { ";
                        for ( DeclarationWithType * assert :  typeDecl->assertions ) {
                                assert->accept( *visitor );
                                output << "; ";
                        }
                        output << " }";
                }
        }

        void CodeGenerator::postvisit( StaticAssertDecl * assertDecl ) {
                output << "_Static_assert(";
                assertDecl->condition->accept( *visitor );
                output << ", ";
                assertDecl->message->accept( *visitor );
                output << ")";
        }

        void CodeGenerator::postvisit( 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( *visitor );
                        } else {
                                // otherwise, it has to be a ConstantExpr or CastExpr, initializing array eleemnt
                                output << "[";
                                des->accept( *visitor );
                                output << "]";
                        } // if
                } // for
                output << " = ";
        }

        void CodeGenerator::postvisit( SingleInit * init ) {
                init->get_value()->accept( *visitor );
        }

        void CodeGenerator::postvisit( 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( *visitor );
                        (*initBegin)->accept( *visitor );
                        ++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::postvisit( ConstructorInit * init ){
                assertf( ! options.genC, "ConstructorInit nodes should not reach code generation." );
                // pseudo-output for constructor/destructor pairs
                output << "<ctorinit>{" << endl << ++indent << "ctor: ";
                maybeAccept( init->get_ctor(), *visitor );
                output << ", " << endl << indent << "dtor: ";
                maybeAccept( init->get_dtor(), *visitor );
                output << endl << --indent << "}";
        }

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

        // *** Expressions
        void CodeGenerator::postvisit( ApplicationExpr * applicationExpr ) {
                extension( applicationExpr );
                if ( VariableExpr * varExpr = dynamic_cast< VariableExpr* >( applicationExpr->get_function() ) ) {
                        const OperatorInfo * opInfo;
                        if ( varExpr->get_var()->get_linkage() == LinkageSpec::Intrinsic && ( opInfo = operatorLookup( varExpr->get_var()->get_name() ) ) ) {
                                std::list< Expression* >::iterator arg = applicationExpr->get_args().begin();
                                switch ( opInfo->type ) {
                                  case OT_INDEX:
                                        assert( applicationExpr->get_args().size() == 2 );
                                        (*arg++)->accept( *visitor );
                                        output << "[";
                                        (*arg)->accept( *visitor );
                                        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( *visitor );
                                                output << ") /* " << opInfo->inputName << " */";
                                        } else if ( applicationExpr->get_args().size() == 2 ) {
                                                // intrinsic two parameter constructors are essentially bitwise assignment
                                                output << "(";
                                                (*arg++)->accept( *visitor );
                                                output << opInfo->symbol;
                                                (*arg)->accept( *visitor );
                                                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( *visitor );
                                        output << ")";
                                        break;

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


                                  case OT_INFIX:
                                  case OT_INFIXASSIGN:
                                        assert( applicationExpr->get_args().size() == 2 );
                                        output << "(";
                                        (*arg++)->accept( *visitor );
                                        output << opInfo->symbol;
                                        (*arg)->accept( *visitor );
                                        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( *visitor );
                                output << "(";
                                genCommaList( applicationExpr->get_args().begin(), applicationExpr->get_args().end() );
                                output << ")";
                        } // if
                } else {
                        applicationExpr->get_function()->accept( *visitor );
                        output << "(";
                        genCommaList( applicationExpr->get_args().begin(), applicationExpr->get_args().end() );
                        output << ")";
                } // if
        }

        void CodeGenerator::postvisit( UntypedExpr * untypedExpr ) {
                extension( untypedExpr );
                if ( NameExpr * nameExpr = dynamic_cast< NameExpr* >( untypedExpr->function ) ) {
                        const OperatorInfo * opInfo = operatorLookup( nameExpr->name );
                        if ( opInfo ) {
                                std::list< Expression* >::iterator arg = untypedExpr->args.begin();
                                switch ( opInfo->type ) {
                                  case OT_INDEX:
                                        assert( untypedExpr->args.size() == 2 );
                                        (*arg++)->accept( *visitor );
                                        output << "[";
                                        (*arg)->accept( *visitor );
                                        output << "]";
                                        break;

                                  case OT_CALL:
                                        assert( false );

                                  case OT_CTOR:
                                  case OT_DTOR:
                                        if ( untypedExpr->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( *visitor );
                                                output << ") /* " << opInfo->inputName << " */";
                                        } else if ( untypedExpr->get_args().size() == 2 ) {
                                                // intrinsic two parameter constructors are essentially bitwise assignment
                                                output << "(";
                                                (*arg++)->accept( *visitor );
                                                output << opInfo->symbol;
                                                (*arg)->accept( *visitor );
                                                output << ") /* " << opInfo->inputName << " */";
                                        } else {
                                                // no constructors with 0 or more than 2 parameters
                                                assertf( ! options.genC, "UntypedExpr constructor/destructor with 0 or more than 2 parameters." );
                                                output << "(";
                                                (*arg++)->accept( *visitor );
                                                output << opInfo->symbol << "{ ";
                                                genCommaList( arg, untypedExpr->args.end() );
                                                output << "}) /* " << opInfo->inputName << " */";
                                        } // if
                                        break;

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

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

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

                                  case OT_CONSTANT:
                                        // there are no intrinsic definitions of 0 or 1 as functions
                                        assert( false );
                                } // switch
                        } else {
                                // builtin routines
                                nameExpr->accept( *visitor );
                                output << "(";
                                genCommaList( untypedExpr->args.begin(), untypedExpr->args.end() );
                                output << ")";
                        } // if
                } else {
                        untypedExpr->function->accept( *visitor );
                        output << "(";
                        genCommaList( untypedExpr->args.begin(), untypedExpr->args.end() );
                        output << ")";
                } // if
        }

        void CodeGenerator::postvisit( RangeExpr * rangeExpr ) {
                rangeExpr->low->accept( *visitor );
                output << " ... ";
                rangeExpr->high->accept( *visitor );
        }

        void CodeGenerator::postvisit( NameExpr * nameExpr ) {
                extension( nameExpr );
                const OperatorInfo * opInfo = operatorLookup( nameExpr->name );
                if ( opInfo ) {
                        if ( opInfo->type == OT_CONSTANT ) {
                                output << opInfo->symbol;
                        } else {
                                output << opInfo->outputName;
                        }
                } else {
                        output << nameExpr->get_name();
                } // if
        }

        void CodeGenerator::postvisit( DimensionExpr * dimensionExpr ) {
                extension( dimensionExpr );
                output << "/*non-type*/" << dimensionExpr->get_name();
        }

        void CodeGenerator::postvisit( AddressExpr * addressExpr ) {
                extension( addressExpr );
                output << "(&";
                addressExpr->arg->accept( *visitor );
                output << ")";
        }

        void CodeGenerator::postvisit( LabelAddressExpr *addressExpr ) {
                extension( addressExpr );
                output << "(&&" << addressExpr->arg << ")";
        }

        void CodeGenerator::postvisit( CastExpr * castExpr ) {
                extension( castExpr );
                output << "(";
                if ( castExpr->get_result()->isVoid() ) {
                        output << "(void)";
                } else {
                        // at least one result type of cast.
                        // Note: previously, lvalue casts were skipped. Since it's now impossible for the user to write
                        // an lvalue cast, this has been taken out.
                        output << "(";
                        output << genType( castExpr->get_result(), "", options );
                        output << ")";
                } // if
                castExpr->arg->accept( *visitor );
                output << ")";
        }

        void CodeGenerator::postvisit( KeywordCastExpr * castExpr ) {
                assertf( ! options.genC, "KeywordCast should not reach code generation." );
                extension( castExpr );
                output << "((" << castExpr->targetString() << " &)";
                castExpr->arg->accept( *visitor );
                output << ")";
        }

        void CodeGenerator::postvisit( VirtualCastExpr * castExpr ) {
                assertf( ! options.genC, "VirtualCastExpr should not reach code generation." );
                extension( castExpr );
                output << "(virtual ";
                castExpr->get_arg()->accept( *visitor );
                output << ")";
        }

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

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

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

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

        void CodeGenerator::postvisit( SizeofExpr * sizeofExpr ) {
                extension( sizeofExpr );
                output << "sizeof(";
                if ( sizeofExpr->get_isType() ) {
                        output << genType( sizeofExpr->get_type(), "", options );
                } else {
                        sizeofExpr->get_expr()->accept( *visitor );
                } // if
                output << ")";
        }

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

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

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

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

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

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

        void CodeGenerator::postvisit( CommaExpr * commaExpr ) {
                extension( commaExpr );
                output << "(";
                if ( options.genC ) {
                        // arg1 of a CommaExpr is never used, so it can be safely cast to void to reduce gcc warnings.
                        commaExpr->set_arg1( new CastExpr( commaExpr->get_arg1() ) );
                }
                commaExpr->get_arg1()->accept( *visitor );
                output << " , ";
                commaExpr->get_arg2()->accept( *visitor );
                output << ")";
        }

        void CodeGenerator::postvisit( TupleAssignExpr * tupleExpr ) {
                assertf( ! options.genC, "TupleAssignExpr should not reach code generation." );
                tupleExpr->stmtExpr->accept( *visitor );
        }

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

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

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

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

        void CodeGenerator::postvisit( AsmExpr * asmExpr ) {
                if ( !asmExpr->inout.empty() ) {
                        output << "[ ";
                        output << asmExpr->inout;
                        output << " ] ";
                } // if
                asmExpr->constraint->accept( *visitor );
                output << " ( ";
                asmExpr->operand->accept( *visitor );
                output << " )";
        }

        void CodeGenerator::postvisit( CompoundLiteralExpr *compLitExpr ) {
                assert( compLitExpr->get_result() && dynamic_cast< ListInit * > ( compLitExpr->get_initializer() ) );
                output << "(" << genType( compLitExpr->get_result(), "", options ) << ")";
                compLitExpr->get_initializer()->accept( *visitor );
        }

        void CodeGenerator::postvisit( UniqueExpr * unqExpr ) {
                assertf( ! options.genC, "Unique expressions should not reach code generation." );
                output << "unq<" << unqExpr->get_id() << ">{ ";
                unqExpr->get_expr()->accept( *visitor );
                output << " }";
        }

        void CodeGenerator::postvisit( StmtExpr * stmtExpr ) {
                std::list< Statement * > & stmts = stmtExpr->statements->kids;
                output << "({" << endl;
                ++indent;
                unsigned int numStmts = stmts.size();
                unsigned int i = 0;
                for ( Statement * stmt : stmts ) {
                        output << indent << 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->expr->accept( *visitor );
                                        output << ";" << endl;
                                        ++i;
                                        break;
                                }
                        }
                        stmt->accept( *visitor );
                        output << endl;
                        if ( wantSpacing( stmt ) ) {
                                output << endl;
                        } // if
                        ++i;
                }
                --indent;
                output << indent << "})";
        }

        void CodeGenerator::postvisit( ConstructorExpr * expr ) {
                assertf( ! options.genC, "Unique expressions should not reach code generation." );
                expr->callExpr->accept( *visitor );
        }

        void CodeGenerator::postvisit( DeletedExpr * expr ) {
                assertf( ! options.genC, "Deleted expressions should not reach code generation." );
                expr->expr->accept( *visitor );
        }

        void CodeGenerator::postvisit( DefaultArgExpr * arg ) {
                assertf( ! options.genC, "Default argument expressions should not reach code generation." );
                arg->expr->accept( *visitor );
        }

        void CodeGenerator::postvisit( GenericExpr * expr ) {
                assertf( ! options.genC, "C11 _Generic expressions should not reach code generation." );
                output << "_Generic(";
                expr->control->accept( *visitor );
                output << ", ";
                unsigned int numAssocs = expr->associations.size();
                unsigned int i = 0;
                for ( GenericExpr::Association & assoc : expr->associations ) {
                        if (assoc.isDefault) {
                                output << "default: ";
                        } else {
                                output << genType( assoc.type, "", options ) << ": ";
                        }
                        assoc.expr->accept( *visitor );
                        if ( i+1 != numAssocs ) {
                                output << ", ";
                        }
                        i++;
                }
                output << ")";
        }


        // *** Statements
        void CodeGenerator::postvisit( 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( *visitor );

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

                output << indent << "}";
        }

        void CodeGenerator::postvisit( ExprStmt * exprStmt ) {
                assert( exprStmt );
                if ( options.genC ) {
                        // cast the top-level expression to void to reduce gcc warnings.
                        exprStmt->set_expr( new CastExpr( exprStmt->get_expr() ) );
                }
                exprStmt->get_expr()->accept( *visitor );
                output << ";";
        }

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

        void CodeGenerator::postvisit( DirectiveDecl * directiveDecl ) {
                output << endl << directiveDecl->get_stmt()->directive; // endl prevents spaces before directive
        }

        void CodeGenerator::postvisit( DirectiveStmt * dirStmt ) {
                output << endl << dirStmt->directive;                   // endl prevents spaces before directive
        }

        void CodeGenerator::postvisit( IfStmt * ifStmt ) {
                output << "if ( ";
                ifStmt->get_condition()->accept( *visitor );
                output << " ) ";

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

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

        void CodeGenerator::postvisit( SwitchStmt * switchStmt ) {
                output << "switch ( ";
                switchStmt->get_condition()->accept( *visitor );
                output << " ) ";

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

        void CodeGenerator::postvisit( CaseStmt * caseStmt ) {
                updateLocation( caseStmt );
                output << indent;
                if ( caseStmt->isDefault()) {
                        output << "default";
                } else {
                        output << "case ";
                        caseStmt->get_condition()->accept( *visitor );
                } // if
                output << ":" << endl;

                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( *visitor );
                        output << endl;
                } // for
                --indent;
        }

        void CodeGenerator::postvisit( 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( *visitor );
                                } // if
                        } // if
                        break;
                  case BranchStmt::Break:
                        output << "break";
                        break;
                  case BranchStmt::Continue:
                        output << "continue";
                        break;
                  case BranchStmt::FallThrough:
                  case BranchStmt::FallThroughDefault:
                        assertf( ! options.genC, "fallthru should not reach code generation." );
                        output << "fallthru";
                        break;
                } // switch
                // print branch target for labelled break/continue/fallthru in debug mode
                if ( ! options.genC && branchStmt->get_type() != BranchStmt::Goto ) {
                        if ( ! branchStmt->get_target().empty() ) {
                                output << " " << branchStmt->get_target();
                        } else if ( branchStmt->get_type() == BranchStmt::FallThrough ) {
                                output << " default";
                        }
                }
                output << ";";
        }

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

        void CodeGenerator::postvisit( ThrowStmt * throwStmt ) {
                assertf( ! options.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( *visitor );
                }
                if (throwStmt->get_target()) {
                        output << " _At ";
                        throwStmt->get_target()->accept( *visitor );
                }
                output << ";";
        }
        void CodeGenerator::postvisit( CatchStmt * stmt ) {
                assertf( ! options.genC, "Catch statements should not reach code generation." );

                output << ((stmt->get_kind() == CatchStmt::Terminate) ?
                                   "catch" : "catchResume");
                output << "( ";
                stmt->decl->accept( *visitor );
                output << " ) ";

                if( stmt->cond ) {
                        output << "if/when(?) (";
                        stmt->cond->accept( *visitor );
                        output << ") ";
                }
                stmt->body->accept( *visitor );
        }

        void CodeGenerator::postvisit( WaitForStmt * stmt ) {
                assertf( ! options.genC, "Waitfor statements should not reach code generation." );

                bool first = true;
                for( auto & clause : stmt->clauses ) {
                        if(first) { output << "or "; first = false; }
                        if( clause.condition ) {
                                output << "when(";
                                stmt->timeout.condition->accept( *visitor );
                                output << ") ";
                        }
                        output << "waitfor(";
                        clause.target.function->accept( *visitor );
                        for( Expression * expr : clause.target.arguments ) {
                                output << ",";
                                expr->accept( *visitor );
                        }
                        output << ") ";
                        clause.statement->accept( *visitor );
                }

                if( stmt->timeout.statement ) {
                        output << "or ";
                        if( stmt->timeout.condition ) {
                                output << "when(";
                                stmt->timeout.condition->accept( *visitor );
                                output << ") ";
                        }
                        output << "timeout(";
                        stmt->timeout.time->accept( *visitor );
                        output << ") ";
                        stmt->timeout.statement->accept( *visitor );
                }

                if( stmt->orelse.statement ) {
                        output << "or ";
                        if( stmt->orelse.condition ) {
                                output << "when(";
                                stmt->orelse.condition->accept( *visitor );
                                output << ")";
                        }
                        output << "else ";
                        stmt->orelse.statement->accept( *visitor );
                }
        }

        void CodeGenerator::postvisit( WithStmt * with ) {
                if ( ! options.genC ) {
                        output << "with ( ";
                        genCommaList( with->exprs.begin(), with->exprs.end() );
                        output << " ) ";
                }
                with->stmt->accept( *visitor );
        }

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

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

                output << indent;

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

        void CodeGenerator::postvisit( 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( *visitor );
                } // 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( *visitor );
                } // if
                output << ") ";

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

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

        void CodeGenerator::postvisit( DeclStmt * declStmt ) {
                declStmt->get_decl()->accept( *visitor );

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

        void CodeGenerator::postvisit( ImplicitCtorDtorStmt * stmt ) {
                assertf( ! options.genC, "ImplicitCtorDtorStmts should not reach code generation." );
                stmt->callStmt->accept( *visitor );
        }

        void CodeGenerator::postvisit( MutexStmt * stmt ) {
                assertf( ! options.genC, "ImplicitCtorDtorStmts should not reach code generation." );
                stmt->stmt->accept( *visitor );
        }

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

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


unsigned Indenter::tabsize = 2;

std::ostream & operator<<( std::ostream & out, const BaseSyntaxNode * node ) {
        if ( node ) {
                node->print( out );
        } else {
                out << "nullptr";
        }
        return out;
}

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