source: src/SymTab/Autogen.cc @ 0afffee

//
// 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.
//
// Autogen.cc --
//
// Author           : Rob Schluntz
// Created On       : Thu Mar 03 15:45:56 2016
// Last Modified By : Peter A. Buhr
// Last Modified On : Tue Jul 12 17:47:17 2016
// Update Count     : 2
//

#include <list>
#include <iterator>
#include "SynTree/Visitor.h"
#include "SynTree/Type.h"
#include "SynTree/Statement.h"
#include "SynTree/TypeSubstitution.h"
#include "Common/utility.h"
#include "AddVisit.h"
#include "MakeLibCfa.h"
#include "Autogen.h"

namespace SymTab {
        Type * SizeType = 0;

        class AutogenerateRoutines : public Visitor {
                public:
                std::list< Declaration * > &get_declsToAdd() { return declsToAdd; }

                virtual void visit( EnumDecl *enumDecl );
                virtual void visit( StructDecl *structDecl );
                virtual void visit( UnionDecl *structDecl );
                virtual void visit( TypeDecl *typeDecl );
                virtual void visit( TraitDecl *ctxDecl );
                virtual void visit( FunctionDecl *functionDecl );

                virtual void visit( FunctionType *ftype );
                virtual void visit( PointerType *ftype );

                virtual void visit( CompoundStmt *compoundStmt );
                virtual void visit( SwitchStmt *switchStmt );

                AutogenerateRoutines() : functionNesting( 0 ) {}
                private:
                template< typename StmtClass > void visitStatement( StmtClass *stmt );

                std::list< Declaration * > declsToAdd;
                std::set< std::string > structsDone;
                unsigned int functionNesting;     // current level of nested functions
        };

        void autogenerateRoutines( std::list< Declaration * > &translationUnit ) {
                AutogenerateRoutines visitor;
                acceptAndAdd( translationUnit, visitor, false );
        }

        bool isUnnamedBitfield( ObjectDecl * obj ) {
                return obj != NULL && obj->get_name() == "" && obj->get_bitfieldWidth() != NULL;
        }

        template< typename OutputIterator >
        void makeUnionFieldsAssignment( ObjectDecl *srcParam, ObjectDecl *dstParam, OutputIterator out ) {
                UntypedExpr *copy = new UntypedExpr( new NameExpr( "__builtin_memcpy" ) );
                copy->get_args().push_back( new VariableExpr( dstParam ) );
                copy->get_args().push_back( new AddressExpr( new VariableExpr( srcParam ) ) );
                copy->get_args().push_back( new SizeofExpr( srcParam->get_type()->clone() ) );

                *out++ = new ExprStmt( noLabels, copy );
        }

        //E ?=?(E volatile*, int),
        //  ?=?(E _Atomic volatile*, int);
        void makeEnumFunctions( EnumDecl *enumDecl, EnumInstType *refType, unsigned int functionNesting, std::list< Declaration * > &declsToAdd ) {
                FunctionType *assignType = new FunctionType( Type::Qualifiers(), false );

                ObjectDecl *dstParam = new ObjectDecl( "_dst", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), refType ), 0 );
                assignType->get_parameters().push_back( dstParam );

                // void ?{}(E *); void ^?{}(E *);
                FunctionType * ctorType = assignType->clone();
                FunctionType * dtorType = assignType->clone();

                ObjectDecl *srcParam = new ObjectDecl( "_src", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, refType->clone(), 0 );
                assignType->get_parameters().push_back( srcParam );
                // void ?{}(E *, E);
                FunctionType *copyCtorType = assignType->clone();

                // T ?=?(E *, E);
                ObjectDecl *returnVal = new ObjectDecl( "", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, refType->clone(), 0 );
                assignType->get_returnVals().push_back( returnVal );

                // xxx - should we also generate void ?{}(E *, int) and E ?{}(E *, E)?
                // right now these cases work, but that might change.

                // Routines at global scope marked "static" to prevent multiple definitions is separate translation units
                // because each unit generates copies of the default routines for each aggregate.
                // xxx - Temporary: make these functions intrinsic so they codegen as C assignment.
                // Really they're something of a cross between instrinsic and autogen, so should
                // probably make a new linkage type
                FunctionDecl *assignDecl = new FunctionDecl( "?=?", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::Intrinsic, assignType, new CompoundStmt( noLabels ), true, false );
                FunctionDecl *ctorDecl = new FunctionDecl( "?{}", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::Intrinsic, ctorType, new CompoundStmt( noLabels ), true, false );
                FunctionDecl *copyCtorDecl = new FunctionDecl( "?{}", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::Intrinsic, copyCtorType, new CompoundStmt( noLabels ), true, false );
                FunctionDecl *dtorDecl = new FunctionDecl( "^?{}", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::Intrinsic, dtorType, new CompoundStmt( noLabels ), true, false );
                assignDecl->fixUniqueId();
                ctorDecl->fixUniqueId();
                copyCtorDecl->fixUniqueId();
                dtorDecl->fixUniqueId();

                // enum copy construct and assignment is just C-style assignment.
                // this looks like a bad recursive call, but code gen will turn it into
                // a C-style assignment.
                // This happens before function pointer type conversion, so need to do it manually here
                VariableExpr * assignVarExpr = new VariableExpr( assignDecl );
                Type *& assignVarExprType = assignVarExpr->get_results().front();
                assignVarExprType = new PointerType( Type::Qualifiers(), assignVarExprType );
                ApplicationExpr * assignExpr = new ApplicationExpr( assignVarExpr );
                assignExpr->get_args().push_back( new VariableExpr( dstParam ) );
                assignExpr->get_args().push_back( new VariableExpr( srcParam ) );

                // body is either return stmt or expr stmt
                assignDecl->get_statements()->get_kids().push_back( new ReturnStmt( noLabels, assignExpr ) );
                copyCtorDecl->get_statements()->get_kids().push_back( new ExprStmt( noLabels, assignExpr->clone() ) );

                declsToAdd.push_back( assignDecl );
                declsToAdd.push_back( ctorDecl );
                declsToAdd.push_back( copyCtorDecl );
                declsToAdd.push_back( dtorDecl );
        }

        /// Clones a reference type, replacing any parameters it may have with a clone of the provided list
        template< typename GenericInstType >
        GenericInstType *cloneWithParams( GenericInstType *refType, const std::list< Expression* >& params ) {
                GenericInstType *clone = refType->clone();
                clone->get_parameters().clear();
                cloneAll( params, clone->get_parameters() );
                return clone;
        }

        /// Creates a new type decl that's the same as src, but renamed and with only the ?=?, ?{} (default and copy), and ^?{} assertions (for complete types only)
        TypeDecl *cloneAndRename( TypeDecl *src, const std::string &name ) {
                // TypeDecl *dst = new TypeDecl( name, src->get_storageClass(), 0, src->get_kind() );

                // if ( src->get_kind() == TypeDecl::Any ) {
                //      TypeInstType *opParamType = new TypeInstType( Type::Qualifiers(), name, dst );
                //      FunctionType *opFunctionType = new FunctionType( Type::Qualifiers(), false );
                //      opFunctionType->get_parameters().push_back(
                //              new ObjectDecl( "", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), opParamType->clone() ), 0 ) );
                //      FunctionDecl *ctorAssert = new FunctionDecl( "?{}", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, opFunctionType->clone(), 0, false, false );
                //      FunctionDecl *dtorAssert = new FunctionDecl( "^?{}", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, opFunctionType->clone(), 0, false, false );

                //      opFunctionType->get_parameters().push_back(
                //              new ObjectDecl( "", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, opParamType, 0 ) );
                //      FunctionDecl *copyCtorAssert = new FunctionDecl( "?{}", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, opFunctionType->clone(), 0, false, false );

                //      opFunctionType->get_returnVals().push_back(
                //              new ObjectDecl( "", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, opParamType->clone(), 0 ) );
                //      FunctionDecl *assignAssert = new FunctionDecl( "?=?", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, opFunctionType, 0, false, false );


                //      dst->get_assertions().push_back( assignAssert );
                //      dst->get_assertions().push_back( ctorAssert );
                //      dst->get_assertions().push_back( dtorAssert );
                //      dst->get_assertions().push_back( copyCtorAssert );
                // }

                TypeDecl *dst = new TypeDecl( src->get_name(), src->get_storageClass(), 0, src->get_kind() );
                cloneAll(src->get_assertions(), dst->get_assertions());
                return dst;
        }

        void makeStructMemberOp( ObjectDecl * dstParam, Expression * src, DeclarationWithType * field, FunctionDecl * func, TypeSubstitution & genericSubs, bool isDynamicLayout, bool forward = true ) {
//              if ( isDynamicLayout && src ) {
//                      genericSubs.apply( src );
//              }

                ObjectDecl * returnVal = NULL;
                if ( ! func->get_functionType()->get_returnVals().empty() ) {
                        returnVal = dynamic_cast<ObjectDecl*>( func->get_functionType()->get_returnVals().front() );
                }

                InitTweak::InitExpander srcParam( src );

                // assign to destination (and return value if generic)
                UntypedExpr *derefExpr = new UntypedExpr( new NameExpr( "*?" ) );
                derefExpr->get_args().push_back( new VariableExpr( dstParam ) );
                Expression *dstselect = new MemberExpr( field, derefExpr );
                genImplicitCall( srcParam, dstselect, func->get_name(), back_inserter( func->get_statements()->get_kids() ), field, forward );

                if ( isDynamicLayout && returnVal ) {
                        UntypedExpr *derefRet = new UntypedExpr( new NameExpr( "*?" ) );
                        derefRet->get_args().push_back( new VariableExpr( returnVal ) );
                        Expression *retselect = new MemberExpr( field, derefRet );
                        genImplicitCall( srcParam, retselect, func->get_name(), back_inserter( func->get_statements()->get_kids() ), field, forward );
                } // if
        }

        template<typename Iterator>
        void makeStructFunctionBody( Iterator member, Iterator end, FunctionDecl * func, TypeSubstitution & genericSubs, bool isDynamicLayout, bool forward = true ) {
                for ( ; member != end; ++member ) {
                        if ( DeclarationWithType *field = dynamic_cast< DeclarationWithType * >( *member ) ) { // otherwise some form of type declaration, e.g. Aggregate
                                // query the type qualifiers of this field and skip assigning it if it is marked const.
                                // If it is an array type, we need to strip off the array layers to find its qualifiers.
                                Type * type = field->get_type();
                                while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
                                        type = at->get_base();
                                }

                                if ( type->get_qualifiers().isConst && func->get_name() == "?=?" ) {
                                        // don't assign const members, but do construct/destruct
                                        continue;
                                }

                                if ( field->get_name() == "" ) {
                                        // don't assign to anonymous members
                                        // xxx - this is a temporary fix. Anonymous members tie into
                                        // our inheritance model. I think the correct way to handle this is to
                                        // cast the structure to the type of the member and let the resolver
                                        // figure out whether it's valid and have a pass afterwards that fixes
                                        // the assignment to use pointer arithmetic with the offset of the
                                        // member, much like how generic type members are handled.
                                        continue;
                                }

                                assert( ! func->get_functionType()->get_parameters().empty() );
                                ObjectDecl * dstParam = dynamic_cast<ObjectDecl*>( func->get_functionType()->get_parameters().front() );
                                ObjectDecl * srcParam = NULL;
                                if ( func->get_functionType()->get_parameters().size() == 2 ) {
                                        srcParam = dynamic_cast<ObjectDecl*>( func->get_functionType()->get_parameters().back() );
                                }
                                // srcParam may be NULL, in which case we have default ctor/dtor
                                assert( dstParam );

                                Expression *srcselect = srcParam ? new MemberExpr( field, new VariableExpr( srcParam ) ) : NULL;
                                makeStructMemberOp( dstParam, srcselect, field, func, genericSubs, isDynamicLayout, forward );
                        } // if
                } // for
        } // makeStructFunctionBody

        /// generate the body of a constructor which takes parameters that match fields, e.g.
        /// void ?{}(A *, int) and void?{}(A *, int, int) for a struct A which has two int fields.
        template<typename Iterator>
        void makeStructFieldCtorBody( Iterator member, Iterator end, FunctionDecl * func, TypeSubstitution & genericSubs, bool isDynamicLayout ) {
                FunctionType * ftype = func->get_functionType();
                std::list<DeclarationWithType*> & params = ftype->get_parameters();
                assert( params.size() >= 2 );  // should not call this function for default ctor, etc.

                // skip 'this' parameter
                ObjectDecl * dstParam = dynamic_cast<ObjectDecl*>( params.front() );
                assert( dstParam );
                std::list<DeclarationWithType*>::iterator parameter = params.begin()+1;
                for ( ; member != end; ++member ) {
                        if ( DeclarationWithType * field = dynamic_cast<DeclarationWithType*>( *member ) ) {
                                if ( isUnnamedBitfield( dynamic_cast< ObjectDecl * > ( field ) ) ) {
                                        // don't make a function whose parameter is an unnamed bitfield
                                        continue;
                                } else if ( field->get_name() == "" ) {
                                        // don't assign to anonymous members
                                        // xxx - this is a temporary fix. Anonymous members tie into
                                        // our inheritance model. I think the correct way to handle this is to
                                        // cast the structure to the type of the member and let the resolver
                                        // figure out whether it's valid and have a pass afterwards that fixes
                                        // the assignment to use pointer arithmetic with the offset of the
                                        // member, much like how generic type members are handled.
                                        continue;
                                } else if ( parameter != params.end() ) {
                                        // matching parameter, initialize field with copy ctor
                                        Expression *srcselect = new VariableExpr(*parameter);
                                        makeStructMemberOp( dstParam, srcselect, field, func, genericSubs, isDynamicLayout );
                                        ++parameter;
                                } else {
                                        // no matching parameter, initialize field with default ctor
                                        makeStructMemberOp( dstParam, NULL, field, func, genericSubs, isDynamicLayout );
                                }
                        }
                }
        }

        void addForwardDecl( FunctionDecl * functionDecl, std::list< Declaration * > & declsToAdd ) {
                FunctionDecl * decl = functionDecl->clone();
                delete decl->get_statements();
                decl->set_statements( NULL );
                declsToAdd.push_back( decl );
                decl->fixUniqueId();
        }

        void makeStructFunctions( StructDecl *aggregateDecl, StructInstType *refType, unsigned int functionNesting, std::list< Declaration * > & declsToAdd ) {
                FunctionType *assignType = new FunctionType( Type::Qualifiers(), false );

                // Make function polymorphic in same parameters as generic struct, if applicable
                bool isDynamicLayout = false;  // NOTE this flag is an incredibly ugly kludge; we should fix the assignment signature instead (ditto for union)
                std::list< TypeDecl* >& genericParams = aggregateDecl->get_parameters();
                std::list< Expression* > structParams;  // List of matching parameters to put on types
                TypeSubstitution genericSubs; // Substitutions to make to member types of struct
                for ( std::list< TypeDecl* >::const_iterator param = genericParams.begin(); param != genericParams.end(); ++param ) {
                        if ( (*param)->get_kind() == TypeDecl::Any ) isDynamicLayout = true;
                        TypeDecl *typeParam = cloneAndRename( *param, "_autoassign_" + aggregateDecl->get_name() + "_" + (*param)->get_name() );
                        assignType->get_forall().push_back( typeParam );
                        TypeInstType *newParamType = new TypeInstType( Type::Qualifiers(), typeParam->get_name(), typeParam );
                        genericSubs.add( (*param)->get_name(), newParamType );
                        structParams.push_back( new TypeExpr( newParamType ) );
                }

                ObjectDecl *dstParam = new ObjectDecl( "_dst", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), cloneWithParams( refType, structParams ) ), 0 );
                assignType->get_parameters().push_back( dstParam );

                // void ?{}(T *); void ^?{}(T *);
                FunctionType *ctorType = assignType->clone();
                FunctionType *dtorType = assignType->clone();

                ObjectDecl *srcParam = new ObjectDecl( "_src", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, cloneWithParams( refType, structParams ), 0 );
                assignType->get_parameters().push_back( srcParam );

                // void ?{}(T *, T);
                FunctionType *copyCtorType = assignType->clone();

                // T ?=?(T *, T);
                ObjectDecl *returnVal = new ObjectDecl( "_ret", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, cloneWithParams( refType, structParams ), 0 );
                assignType->get_returnVals().push_back( returnVal );

                // Routines at global scope marked "static" to prevent multiple definitions is separate translation units
                // because each unit generates copies of the default routines for each aggregate.
                FunctionDecl *assignDecl = new FunctionDecl( "?=?", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, assignType, new CompoundStmt( noLabels ), true, false );
                FunctionDecl *ctorDecl = new FunctionDecl( "?{}", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, ctorType, new CompoundStmt( noLabels ), true, false );
                FunctionDecl *copyCtorDecl = new FunctionDecl( "?{}", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, copyCtorType, new CompoundStmt( noLabels ), true, false );
                FunctionDecl *dtorDecl = new FunctionDecl( "^?{}", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, dtorType, new CompoundStmt( noLabels ), true, false );
                assignDecl->fixUniqueId();
                ctorDecl->fixUniqueId();
                copyCtorDecl->fixUniqueId();
                dtorDecl->fixUniqueId();

                if ( functionNesting == 0 ) {
                        // forward declare if top-level struct, so that
                        // type is complete as soon as its body ends
                        addForwardDecl( assignDecl, declsToAdd );
                        addForwardDecl( ctorDecl, declsToAdd );
                        addForwardDecl( copyCtorDecl, declsToAdd );
                        addForwardDecl( dtorDecl, declsToAdd );
                }

                // create constructors which take each member type as a parameter.
                // for example, for struct A { int x, y; }; generate
                // void ?{}(A *, int) and void ?{}(A *, int, int)
                std::list<Declaration *> memCtors;
                FunctionType * memCtorType = ctorType->clone();
                for ( std::list<Declaration *>::iterator i = aggregateDecl->get_members().begin(); i != aggregateDecl->get_members().end(); ++i ) {
                        DeclarationWithType * member = dynamic_cast<DeclarationWithType *>( *i );
                        assert( member );
                        if ( isUnnamedBitfield( dynamic_cast< ObjectDecl * > ( member ) ) ) {
                                // don't make a function whose parameter is an unnamed bitfield
                                continue;
                        } else if ( member->get_name() == "" ) {
                                // don't assign to anonymous members
                                // xxx - this is a temporary fix. Anonymous members tie into
                                // our inheritance model. I think the correct way to handle this is to
                                // cast the structure to the type of the member and let the resolver
                                // figure out whether it's valid and have a pass afterwards that fixes
                                // the assignment to use pointer arithmetic with the offset of the
                                // member, much like how generic type members are handled.
                                continue;
                        }
                        memCtorType->get_parameters().push_back( new ObjectDecl( member->get_name(), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, member->get_type()->clone(), 0 ) );
                        FunctionDecl * ctor = new FunctionDecl( "?{}", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, memCtorType->clone(), new CompoundStmt( noLabels ), true, false );
                        ctor->fixUniqueId();
                        makeStructFieldCtorBody( aggregateDecl->get_members().begin(), aggregateDecl->get_members().end(), ctor, genericSubs, isDynamicLayout );
                        memCtors.push_back( ctor );
                }
                delete memCtorType;

                // generate appropriate calls to member ctor, assignment
                makeStructFunctionBody( aggregateDecl->get_members().begin(), aggregateDecl->get_members().end(), assignDecl, genericSubs, isDynamicLayout );
                makeStructFunctionBody( aggregateDecl->get_members().begin(), aggregateDecl->get_members().end(), ctorDecl, genericSubs, isDynamicLayout );
                makeStructFunctionBody( aggregateDecl->get_members().begin(), aggregateDecl->get_members().end(), copyCtorDecl, genericSubs, isDynamicLayout );
                // needs to do everything in reverse, so pass "forward" as false
                makeStructFunctionBody( aggregateDecl->get_members().rbegin(), aggregateDecl->get_members().rend(), dtorDecl, genericSubs, isDynamicLayout, false );

                if ( ! isDynamicLayout ) assignDecl->get_statements()->get_kids().push_back( new ReturnStmt( noLabels, new VariableExpr( srcParam ) ) );

                declsToAdd.push_back( assignDecl );
                declsToAdd.push_back( ctorDecl );
                declsToAdd.push_back( copyCtorDecl );
                declsToAdd.push_back( dtorDecl );
                declsToAdd.splice( declsToAdd.end(), memCtors );
        }

        void makeUnionFunctions( UnionDecl *aggregateDecl, UnionInstType *refType, unsigned int functionNesting, std::list< Declaration * > & declsToAdd ) {
                FunctionType *assignType = new FunctionType( Type::Qualifiers(), false );

                // Make function polymorphic in same parameters as generic union, if applicable
                bool isDynamicLayout = false; // NOTE this flag is an incredibly ugly kludge; we should fix the assignment signature instead (ditto for struct)
                std::list< TypeDecl* >& genericParams = aggregateDecl->get_parameters();
                std::list< Expression* > unionParams;  // List of matching parameters to put on types
                for ( std::list< TypeDecl* >::const_iterator param = genericParams.begin(); param != genericParams.end(); ++param ) {
                        if ( (*param)->get_kind() == TypeDecl::Any ) isDynamicLayout = true;
                        TypeDecl *typeParam = cloneAndRename( *param, "_autoassign_" + aggregateDecl->get_name() + "_" + (*param)->get_name() );
                        assignType->get_forall().push_back( typeParam );
                        unionParams.push_back( new TypeExpr( new TypeInstType( Type::Qualifiers(), typeParam->get_name(), typeParam ) ) );
                }

                ObjectDecl *dstParam = new ObjectDecl( "_dst", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), cloneWithParams( refType, unionParams ) ), 0 );
                assignType->get_parameters().push_back( dstParam );

                // default ctor/dtor need only first parameter
                FunctionType * ctorType = assignType->clone();
                FunctionType * dtorType = assignType->clone();

                ObjectDecl *srcParam = new ObjectDecl( "_src", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, cloneWithParams( refType, unionParams ), 0 );
                assignType->get_parameters().push_back( srcParam );

                // copy ctor needs both parameters
                FunctionType * copyCtorType = assignType->clone();

                // assignment needs both and return value
                ObjectDecl *returnVal = new ObjectDecl( "_ret", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, cloneWithParams( refType, unionParams ), 0 );
                assignType->get_returnVals().push_back( returnVal );

                // Routines at global scope marked "static" to prevent multiple definitions is separate translation units
                // because each unit generates copies of the default routines for each aggregate.
                FunctionDecl *assignDecl = new FunctionDecl( "?=?",  functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, assignType, new CompoundStmt( noLabels ), true, false );
                FunctionDecl *ctorDecl = new FunctionDecl( "?{}",  functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, ctorType, new CompoundStmt( noLabels ), true, false );
                FunctionDecl *copyCtorDecl = new FunctionDecl( "?{}",  functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, copyCtorType, NULL, true, false );
                FunctionDecl *dtorDecl = new FunctionDecl( "^?{}",  functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, dtorType, new CompoundStmt( noLabels ), true, false );

                assignDecl->fixUniqueId();
                ctorDecl->fixUniqueId();
                copyCtorDecl->fixUniqueId();
                dtorDecl->fixUniqueId();

                makeUnionFieldsAssignment( srcParam, dstParam, back_inserter( assignDecl->get_statements()->get_kids() ) );
                if ( isDynamicLayout ) makeUnionFieldsAssignment( srcParam, returnVal, back_inserter( assignDecl->get_statements()->get_kids() ) );
                else assignDecl->get_statements()->get_kids().push_back( new ReturnStmt( noLabels, new VariableExpr( srcParam ) ) );

                // body of assignment and copy ctor is the same
                copyCtorDecl->set_statements( assignDecl->get_statements()->clone() );

                // create a constructor which takes the first member type as a parameter.
                // for example, for Union A { int x; double y; }; generate
                // void ?{}(A *, int)
                // This is to mimic C's behaviour which initializes the first member of the union.
                std::list<Declaration *> memCtors;
                for ( Declaration * member : aggregateDecl->get_members() ) {
                        if ( DeclarationWithType * field = dynamic_cast< DeclarationWithType * >( member ) ) {
                                ObjectDecl * srcParam = new ObjectDecl( "src", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, field->get_type()->clone(), 0 );

                                FunctionType * memCtorType = ctorType->clone();
                                memCtorType->get_parameters().push_back( srcParam );
                                FunctionDecl * ctor = new FunctionDecl( "?{}", functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, memCtorType, new CompoundStmt( noLabels ), true, false );
                                ctor->fixUniqueId();

                                makeUnionFieldsAssignment( srcParam, dstParam, back_inserter( ctor->get_statements()->get_kids() ) );
                                memCtors.push_back( ctor );
                                // only generate a ctor for the first field
                                break;
                        }
                }

                declsToAdd.push_back( assignDecl );
                declsToAdd.push_back( ctorDecl );
                declsToAdd.push_back( copyCtorDecl );
                declsToAdd.push_back( dtorDecl );
                declsToAdd.splice( declsToAdd.end(), memCtors );
        }

        void AutogenerateRoutines::visit( EnumDecl *enumDecl ) {
                if ( ! enumDecl->get_members().empty() ) {
                        EnumInstType *enumInst = new EnumInstType( Type::Qualifiers(), enumDecl->get_name() );
                        // enumInst->set_baseEnum( enumDecl );
                        // declsToAdd.push_back(
                        makeEnumFunctions( enumDecl, enumInst, functionNesting, declsToAdd );
                }
        }

        void AutogenerateRoutines::visit( StructDecl *structDecl ) {
                if ( ! structDecl->get_members().empty() && structsDone.find( structDecl->get_name() ) == structsDone.end() ) {
                        StructInstType structInst( Type::Qualifiers(), structDecl->get_name() );
                        structInst.set_baseStruct( structDecl );
                        makeStructFunctions( structDecl, &structInst, functionNesting, declsToAdd );
                        structsDone.insert( structDecl->get_name() );
                } // if
        }

        void AutogenerateRoutines::visit( UnionDecl *unionDecl ) {
                if ( ! unionDecl->get_members().empty() ) {
                        UnionInstType unionInst( Type::Qualifiers(), unionDecl->get_name() );
                        unionInst.set_baseUnion( unionDecl );
                        makeUnionFunctions( unionDecl, &unionInst, functionNesting, declsToAdd );
                } // if
        }

        void AutogenerateRoutines::visit( TypeDecl *typeDecl ) {
                CompoundStmt *stmts = 0;
                TypeInstType *typeInst = new TypeInstType( Type::Qualifiers(), typeDecl->get_name(), false );
                typeInst->set_baseType( typeDecl );
                ObjectDecl *src = new ObjectDecl( "_src", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, typeInst->clone(), 0 );
                ObjectDecl *dst = new ObjectDecl( "_dst", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), typeInst->clone() ), 0 );
                if ( typeDecl->get_base() ) {
                        // xxx - generate ctor/dtors for typedecls, e.g.
                        // otype T = int *;
                        stmts = new CompoundStmt( std::list< Label >() );
                        UntypedExpr *assign = new UntypedExpr( new NameExpr( "?=?" ) );
                        assign->get_args().push_back( new CastExpr( new VariableExpr( dst ), new PointerType( Type::Qualifiers(), typeDecl->get_base()->clone() ) ) );
                        assign->get_args().push_back( new CastExpr( new VariableExpr( src ), typeDecl->get_base()->clone() ) );
                        stmts->get_kids().push_back( new ReturnStmt( std::list< Label >(), assign ) );
                } // if
                FunctionType *type = new FunctionType( Type::Qualifiers(), false );
                type->get_returnVals().push_back( new ObjectDecl( "", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, typeInst, 0 ) );
                type->get_parameters().push_back( dst );
                type->get_parameters().push_back( src );
                FunctionDecl *func = new FunctionDecl( "?=?", DeclarationNode::NoStorageClass, LinkageSpec::AutoGen, type, stmts, true, false );
                declsToAdd.push_back( func );
        }

        void addDecls( std::list< Declaration * > &declsToAdd, std::list< Statement * > &statements, std::list< Statement * >::iterator i ) {
                for ( std::list< Declaration * >::iterator decl = declsToAdd.begin(); decl != declsToAdd.end(); ++decl ) {
                        statements.insert( i, new DeclStmt( noLabels, *decl ) );
                } // for
                declsToAdd.clear();
        }

        void AutogenerateRoutines::visit( FunctionType *) {
                // ensure that we don't add assignment ops for types defined as part of the function
        }

        void AutogenerateRoutines::visit( PointerType *) {
                // ensure that we don't add assignment ops for types defined as part of the pointer
        }

        void AutogenerateRoutines::visit( TraitDecl *) {
                // ensure that we don't add assignment ops for types defined as part of the trait
        }

        template< typename StmtClass >
        inline void AutogenerateRoutines::visitStatement( StmtClass *stmt ) {
                std::set< std::string > oldStructs = structsDone;
                addVisit( stmt, *this );
                structsDone = oldStructs;
        }

        void AutogenerateRoutines::visit( FunctionDecl *functionDecl ) {
                maybeAccept( functionDecl->get_functionType(), *this );
                acceptAll( functionDecl->get_oldDecls(), *this );
                functionNesting += 1;
                maybeAccept( functionDecl->get_statements(), *this );
                functionNesting -= 1;
        }

        void AutogenerateRoutines::visit( CompoundStmt *compoundStmt ) {
                visitStatement( compoundStmt );
        }

        void AutogenerateRoutines::visit( SwitchStmt *switchStmt ) {
                visitStatement( switchStmt );
        }
} // SymTab