source: src/GenPoly/Box.cc@ 17e5e2b

//
// 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.
//
// Box.cc --
//
// Author           : Richard C. Bilson
// Created On       : Mon May 18 07:44:20 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Wed Jun 29 21:43:03 2016
// Update Count     : 296
//

#include <algorithm>
#include <iterator>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <cassert>

#include "Box.h"
#include "DeclMutator.h"
#include "PolyMutator.h"
#include "FindFunction.h"
#include "ScopedSet.h"
#include "ScrubTyVars.h"

#include "Parser/ParseNode.h"

#include "SynTree/Constant.h"
#include "SynTree/Declaration.h"
#include "SynTree/Expression.h"
#include "SynTree/Initializer.h"
#include "SynTree/Mutator.h"
#include "SynTree/Statement.h"
#include "SynTree/Type.h"
#include "SynTree/TypeSubstitution.h"

#include "ResolvExpr/TypeEnvironment.h"
#include "ResolvExpr/TypeMap.h"
#include "ResolvExpr/typeops.h"

#include "SymTab/Indexer.h"
#include "SymTab/Mangler.h"

#include "Common/ScopedMap.h"
#include "Common/SemanticError.h"
#include "Common/UniqueName.h"
#include "Common/utility.h"

#include "InitTweak/InitTweak.h"

#include <ext/functional> // temporary

namespace GenPoly {
        namespace {
                const std::list<Label> noLabels;

                FunctionType *makeAdapterType( FunctionType *adaptee, const TyVarMap &tyVars );

                /// Adds layout-generation functions to polymorphic types
                class LayoutFunctionBuilder final : public DeclMutator {
                        unsigned int functionNesting;  // current level of nested functions
                public:
                        LayoutFunctionBuilder() : functionNesting( 0 ) {}

                        using DeclMutator::mutate;
                        virtual DeclarationWithType *mutate( FunctionDecl *functionDecl ) override;
                        virtual Declaration *mutate( StructDecl *structDecl ) override;
                        virtual Declaration *mutate( UnionDecl *unionDecl ) override;
                };

                /// Replaces polymorphic return types with out-parameters, replaces calls to polymorphic functions with adapter calls as needed, and adds appropriate type variables to the function call
                class Pass1 final : public PolyMutator {
                  public:
                        Pass1();

                        using PolyMutator::mutate;
                        virtual Expression *mutate( ApplicationExpr *appExpr ) override;
                        virtual Expression *mutate( AddressExpr *addrExpr ) override;
                        virtual Expression *mutate( UntypedExpr *expr ) override;
                        virtual DeclarationWithType* mutate( FunctionDecl *functionDecl ) override;
                        virtual TypeDecl *mutate( TypeDecl *typeDecl ) override;
                        virtual Expression *mutate( CommaExpr *commaExpr ) override;
                        virtual Expression *mutate( ConditionalExpr *condExpr ) override;
                        virtual Statement * mutate( ReturnStmt *returnStmt ) override;
                        virtual Type *mutate( PointerType *pointerType ) override;
                        virtual Type * mutate( FunctionType *functionType ) override;

                        virtual void doBeginScope() override;
                        virtual void doEndScope() override;
                  private:
                        /// Pass the extra type parameters from polymorphic generic arguments or return types into a function application
                        void passArgTypeVars( ApplicationExpr *appExpr, Type *parmType, Type *argBaseType, std::list< Expression *>::iterator &arg, const TyVarMap &exprTyVars, std::set< std::string > &seenTypes );
                        /// passes extra type parameters into a polymorphic function application
                        void passTypeVars( ApplicationExpr *appExpr, Type *polyRetType, std::list< Expression *>::iterator &arg, const TyVarMap &exprTyVars );
                        /// wraps a function application with a new temporary for the out-parameter return value
                        Expression *addRetParam( ApplicationExpr *appExpr, FunctionType *function, Type *retType, std::list< Expression *>::iterator &arg );
                        /// Replaces all the type parameters of a generic type with their concrete equivalents under the current environment
                        void replaceParametersWithConcrete( ApplicationExpr *appExpr, std::list< Expression* >& params );
                        /// Replaces a polymorphic type with its concrete equivalant under the current environment (returns itself if concrete).
                        /// If `doClone` is set to false, will not clone interior types
                        Type *replaceWithConcrete( ApplicationExpr *appExpr, Type *type, bool doClone = true );
                        /// wraps a function application returning a polymorphic type with a new temporary for the out-parameter return value
                        Expression *addDynRetParam( ApplicationExpr *appExpr, FunctionType *function, Type *polyType, std::list< Expression *>::iterator &arg );
                        Expression *applyAdapter( ApplicationExpr *appExpr, FunctionType *function, std::list< Expression *>::iterator &arg, const TyVarMap &exprTyVars );
                        void boxParam( Type *formal, Expression *&arg, const TyVarMap &exprTyVars );
                        void boxParams( ApplicationExpr *appExpr, FunctionType *function, std::list< Expression *>::iterator &arg, const TyVarMap &exprTyVars );
                        void addInferredParams( ApplicationExpr *appExpr, FunctionType *functionType, std::list< Expression *>::iterator &arg, const TyVarMap &tyVars );
                        /// Stores assignment operators from assertion list in local map of assignment operations
                        void passAdapters( ApplicationExpr *appExpr, FunctionType *functionType, const TyVarMap &exprTyVars );
                        FunctionDecl *makeAdapter( FunctionType *adaptee, FunctionType *realType, const std::string &mangleName, const TyVarMap &tyVars );
                        /// Replaces intrinsic operator functions with their arithmetic desugaring
                        Expression *handleIntrinsics( ApplicationExpr *appExpr );
                        /// Inserts a new temporary variable into the current scope with an auto-generated name
                        ObjectDecl *makeTemporary( Type *type );

                        ScopedMap< std::string, DeclarationWithType* > adapters;     ///< Set of adapter functions in the current scope

                        std::map< ApplicationExpr *, Expression * > retVals;

                        DeclarationWithType *retval;
                        UniqueName tempNamer;
                };

                /// * Moves polymorphic returns in function types to pointer-type parameters
                /// * adds type size and assertion parameters to parameter lists
                class Pass2 final : public PolyMutator {
                  public:
                        template< typename DeclClass >
                        DeclClass *handleDecl( DeclClass *decl, Type *type );

                        using PolyMutator::mutate;
                        virtual DeclarationWithType *mutate( FunctionDecl *functionDecl ) override;
                        virtual ObjectDecl *mutate( ObjectDecl *objectDecl ) override;
                        virtual TypeDecl *mutate( TypeDecl *typeDecl ) override;
                        virtual TypedefDecl *mutate( TypedefDecl *typedefDecl ) override;
                        virtual Type *mutate( PointerType *pointerType ) override;
                        virtual Type *mutate( FunctionType *funcType ) override;

                  private:
                        void addAdapters( FunctionType *functionType );

                        std::map< UniqueId, std::string > adapterName;
                };

                /// Replaces member and size/align/offsetof expressions on polymorphic generic types with calculated expressions.
                /// * Replaces member expressions for polymorphic types with calculated add-field-offset-and-dereference
                /// * Calculates polymorphic offsetof expressions from offset array
                /// * Inserts dynamic calculation of polymorphic type layouts where needed
                class PolyGenericCalculator final : public PolyMutator {
                public:
                        typedef PolyMutator Parent;
                        using Parent::mutate;

                        template< typename DeclClass >
                        DeclClass *handleDecl( DeclClass *decl, Type *type );
                        virtual DeclarationWithType *mutate( FunctionDecl *functionDecl ) override;
                        virtual ObjectDecl *mutate( ObjectDecl *objectDecl ) override;
                        virtual TypedefDecl *mutate( TypedefDecl *objectDecl ) override;
                        virtual TypeDecl *mutate( TypeDecl *objectDecl ) override;
                        virtual Statement *mutate( DeclStmt *declStmt ) override;
                        virtual Type *mutate( PointerType *pointerType ) override;
                        virtual Type *mutate( FunctionType *funcType ) override;
                        virtual Expression *mutate( MemberExpr *memberExpr ) override;
                        virtual Expression *mutate( SizeofExpr *sizeofExpr ) override;
                        virtual Expression *mutate( AlignofExpr *alignofExpr ) override;
                        virtual Expression *mutate( OffsetofExpr *offsetofExpr ) override;
                        virtual Expression *mutate( OffsetPackExpr *offsetPackExpr ) override;

                        virtual void doBeginScope() override;
                        virtual void doEndScope() override;

                private:
                        /// Makes a new variable in the current scope with the given name, type & optional initializer
                        ObjectDecl *makeVar( const std::string &name, Type *type, Initializer *init = 0 );
                        /// returns true if the type has a dynamic layout; such a layout will be stored in appropriately-named local variables when the function returns
                        bool findGeneric( Type *ty );
                        /// adds type parameters to the layout call; will generate the appropriate parameters if needed
                        void addOtypeParamsToLayoutCall( UntypedExpr *layoutCall, const std::list< Type* > &otypeParams );

                        /// Enters a new scope for type-variables, adding the type variables from ty
                        void beginTypeScope( Type *ty );
                        /// Exits the type-variable scope
                        void endTypeScope();

                        ScopedSet< std::string > knownLayouts;          ///< Set of generic type layouts known in the current scope, indexed by sizeofName
                        ScopedSet< std::string > knownOffsets;          ///< Set of non-generic types for which the offset array exists in the current scope, indexed by offsetofName
                };

                /// Replaces initialization of polymorphic values with alloca, declaration of dtype/ftype with appropriate void expression, and sizeof expressions of polymorphic types with the proper variable
                class Pass3 final : public PolyMutator {
                  public:
                        template< typename DeclClass >
                        DeclClass *handleDecl( DeclClass *decl, Type *type );

                        using PolyMutator::mutate;
                        virtual DeclarationWithType *mutate( FunctionDecl *functionDecl ) override;
                        virtual ObjectDecl *mutate( ObjectDecl *objectDecl ) override;
                        virtual TypedefDecl *mutate( TypedefDecl *objectDecl ) override;
                        virtual TypeDecl *mutate( TypeDecl *objectDecl ) override;
                        virtual Type *mutate( PointerType *pointerType ) override;
                        virtual Type *mutate( FunctionType *funcType ) override;
                  private:
                };

        } // anonymous namespace

        /// version of mutateAll with special handling for translation unit so you can check the end of the prelude when debugging
        template< typename MutatorType >
        inline void mutateTranslationUnit( std::list< Declaration* > &translationUnit, MutatorType &mutator ) {
                bool seenIntrinsic = false;
                SemanticError errors;
                for ( typename std::list< Declaration* >::iterator i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
                        try {
                                if ( *i ) {
                                        if ( (*i)->get_linkage() == LinkageSpec::Intrinsic ) {
                                                seenIntrinsic = true;
                                        } else if ( seenIntrinsic ) {
                                                seenIntrinsic = false; // break on this line when debugging for end of prelude
                                        }

                                        *i = dynamic_cast< Declaration* >( (*i)->acceptMutator( mutator ) );
                                        assert( *i );
                                } // if
                        } catch( SemanticError &e ) {
                                errors.append( e );
                        } // try
                } // for
                if ( ! errors.isEmpty() ) {
                        throw errors;
                } // if
        }

        void box( std::list< Declaration *>& translationUnit ) {
                LayoutFunctionBuilder layoutBuilder;
                Pass1 pass1;
                Pass2 pass2;
                PolyGenericCalculator polyCalculator;
                Pass3 pass3;

                layoutBuilder.mutateDeclarationList( translationUnit );
                mutateTranslationUnit/*All*/( translationUnit, pass1 );
                mutateTranslationUnit/*All*/( translationUnit, pass2 );
                mutateTranslationUnit/*All*/( translationUnit, polyCalculator );
                mutateTranslationUnit/*All*/( translationUnit, pass3 );
        }

        ////////////////////////////////// LayoutFunctionBuilder ////////////////////////////////////////////

        DeclarationWithType *LayoutFunctionBuilder::mutate( FunctionDecl *functionDecl ) {
                functionDecl->set_functionType( maybeMutate( functionDecl->get_functionType(), *this ) );
                mutateAll( functionDecl->get_oldDecls(), *this );
                ++functionNesting;
                functionDecl->set_statements( maybeMutate( functionDecl->get_statements(), *this ) );
                --functionNesting;
                return functionDecl;
        }

        /// Get a list of type declarations that will affect a layout function
        std::list< TypeDecl* > takeOtypeOnly( std::list< TypeDecl* > &decls ) {
                std::list< TypeDecl * > otypeDecls;

                for ( std::list< TypeDecl* >::const_iterator decl = decls.begin(); decl != decls.end(); ++decl ) {
                        if ( (*decl)->isComplete() ) {
                                otypeDecls.push_back( *decl );
                        }
                }

                return otypeDecls;
        }

        /// Adds parameters for otype layout to a function type
        void addOtypeParams( FunctionType *layoutFnType, std::list< TypeDecl* > &otypeParams ) {
                BasicType sizeAlignType( Type::Qualifiers(), BasicType::LongUnsignedInt );

                for ( std::list< TypeDecl* >::const_iterator param = otypeParams.begin(); param != otypeParams.end(); ++param ) {
                        TypeInstType paramType( Type::Qualifiers(), (*param)->get_name(), *param );
                        std::string paramName = mangleType( &paramType );
                        layoutFnType->get_parameters().push_back( new ObjectDecl( sizeofName( paramName ), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, sizeAlignType.clone(), 0 ) );
                        layoutFnType->get_parameters().push_back( new ObjectDecl( alignofName( paramName ), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, sizeAlignType.clone(), 0 ) );
                }
        }

        /// Builds a layout function declaration
        FunctionDecl *buildLayoutFunctionDecl( AggregateDecl *typeDecl, unsigned int functionNesting, FunctionType *layoutFnType ) {
                // 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 *layoutDecl = new FunctionDecl(
                        layoutofName( typeDecl ), functionNesting > 0 ? DeclarationNode::NoStorageClass : DeclarationNode::Static, LinkageSpec::AutoGen, layoutFnType, new CompoundStmt( noLabels ), true, false );
                layoutDecl->fixUniqueId();
                return layoutDecl;
        }

        /// Makes a unary operation
        Expression *makeOp( const std::string &name, Expression *arg ) {
                UntypedExpr *expr = new UntypedExpr( new NameExpr( name ) );
                expr->get_args().push_back( arg );
                return expr;
        }

        /// Makes a binary operation
        Expression *makeOp( const std::string &name, Expression *lhs, Expression *rhs ) {
                UntypedExpr *expr = new UntypedExpr( new NameExpr( name ) );
                expr->get_args().push_back( lhs );
                expr->get_args().push_back( rhs );
                return expr;
        }

        /// Returns the dereference of a local pointer variable
        Expression *derefVar( ObjectDecl *var ) {
                return makeOp( "*?", new VariableExpr( var ) );
        }

        /// makes an if-statement with a single-expression if-block and no then block
        Statement *makeCond( Expression *cond, Expression *ifPart ) {
                return new IfStmt( noLabels, cond, new ExprStmt( noLabels, ifPart ), 0 );
        }

        /// makes a statement that assigns rhs to lhs if lhs < rhs
        Statement *makeAssignMax( Expression *lhs, Expression *rhs ) {
                return makeCond( makeOp( "?<?", lhs, rhs ), makeOp( "?=?", lhs->clone(), rhs->clone() ) );
        }

        /// makes a statement that aligns lhs to rhs (rhs should be an integer power of two)
        Statement *makeAlignTo( Expression *lhs, Expression *rhs ) {
                // check that the lhs is zeroed out to the level of rhs
                Expression *ifCond = makeOp( "?&?", lhs, makeOp( "?-?", rhs, new ConstantExpr( Constant( new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt ), "1" ) ) ) );
                // if not aligned, increment to alignment
                Expression *ifExpr = makeOp( "?+=?", lhs->clone(), makeOp( "?-?", rhs->clone(), ifCond->clone() ) );
                return makeCond( ifCond, ifExpr );
        }

        /// adds an expression to a compound statement
        void addExpr( CompoundStmt *stmts, Expression *expr ) {
                stmts->get_kids().push_back( new ExprStmt( noLabels, expr ) );
        }

        /// adds a statement to a compound statement
        void addStmt( CompoundStmt *stmts, Statement *stmt ) {
                stmts->get_kids().push_back( stmt );
        }

        Declaration *LayoutFunctionBuilder::mutate( StructDecl *structDecl ) {
                // do not generate layout function for "empty" tag structs
                if ( structDecl->get_members().empty() ) return structDecl;

                // get parameters that can change layout, exiting early if none
                std::list< TypeDecl* > otypeParams = takeOtypeOnly( structDecl->get_parameters() );
                if ( otypeParams.empty() ) return structDecl;

                // build layout function signature
                FunctionType *layoutFnType = new FunctionType( Type::Qualifiers(), false );
                BasicType *sizeAlignType = new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt );
                PointerType *sizeAlignOutType = new PointerType( Type::Qualifiers(), sizeAlignType );

                ObjectDecl *sizeParam = new ObjectDecl( sizeofName( structDecl->get_name() ), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, sizeAlignOutType, 0 );
                layoutFnType->get_parameters().push_back( sizeParam );
                ObjectDecl *alignParam = new ObjectDecl( alignofName( structDecl->get_name() ), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, sizeAlignOutType->clone(), 0 );
                layoutFnType->get_parameters().push_back( alignParam );
                ObjectDecl *offsetParam = new ObjectDecl( offsetofName( structDecl->get_name() ), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, sizeAlignOutType->clone(), 0 );
                layoutFnType->get_parameters().push_back( offsetParam );
                addOtypeParams( layoutFnType, otypeParams );

                // build function decl
                FunctionDecl *layoutDecl = buildLayoutFunctionDecl( structDecl, functionNesting, layoutFnType );

                // calculate struct layout in function body

                // initialize size and alignment to 0 and 1 (will have at least one member to re-edit size
                addExpr( layoutDecl->get_statements(), makeOp( "?=?", derefVar( sizeParam ), new ConstantExpr( Constant( sizeAlignType->clone(), "0" ) ) ) );
                addExpr( layoutDecl->get_statements(), makeOp( "?=?", derefVar( alignParam ), new ConstantExpr( Constant( sizeAlignType->clone(), "1" ) ) ) );
                unsigned long n_members = 0;
                bool firstMember = true;
                for ( std::list< Declaration* >::const_iterator member = structDecl->get_members().begin(); member != structDecl->get_members().end(); ++member ) {
                        DeclarationWithType *dwt = dynamic_cast< DeclarationWithType * >( *member );
                        assert( dwt );
                        Type *memberType = dwt->get_type();

                        if ( firstMember ) {
                                firstMember = false;
                        } else {
                                // make sure all members after the first (automatically aligned at 0) are properly padded for alignment
                                addStmt( layoutDecl->get_statements(), makeAlignTo( derefVar( sizeParam ), new AlignofExpr( memberType->clone() ) ) );
                        }

                        // place current size in the current offset index
                        addExpr( layoutDecl->get_statements(), makeOp( "?=?", makeOp( "?[?]", new VariableExpr( offsetParam ), new ConstantExpr( Constant::from_ulong( n_members ) ) ),
                                                                              derefVar( sizeParam ) ) );
                        ++n_members;

                        // add member size to current size
                        addExpr( layoutDecl->get_statements(), makeOp( "?+=?", derefVar( sizeParam ), new SizeofExpr( memberType->clone() ) ) );

                        // take max of member alignment and global alignment
                        addStmt( layoutDecl->get_statements(), makeAssignMax( derefVar( alignParam ), new AlignofExpr( memberType->clone() ) ) );
                }
                // make sure the type is end-padded to a multiple of its alignment
                addStmt( layoutDecl->get_statements(), makeAlignTo( derefVar( sizeParam ), derefVar( alignParam ) ) );

                addDeclarationAfter( layoutDecl );
                return structDecl;
        }

        Declaration *LayoutFunctionBuilder::mutate( UnionDecl *unionDecl ) {
                // do not generate layout function for "empty" tag unions
                if ( unionDecl->get_members().empty() ) return unionDecl;

                // get parameters that can change layout, exiting early if none
                std::list< TypeDecl* > otypeParams = takeOtypeOnly( unionDecl->get_parameters() );
                if ( otypeParams.empty() ) return unionDecl;

                // build layout function signature
                FunctionType *layoutFnType = new FunctionType( Type::Qualifiers(), false );
                BasicType *sizeAlignType = new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt );
                PointerType *sizeAlignOutType = new PointerType( Type::Qualifiers(), sizeAlignType );

                ObjectDecl *sizeParam = new ObjectDecl( sizeofName( unionDecl->get_name() ), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, sizeAlignOutType, 0 );
                layoutFnType->get_parameters().push_back( sizeParam );
                ObjectDecl *alignParam = new ObjectDecl( alignofName( unionDecl->get_name() ), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, sizeAlignOutType->clone(), 0 );
                layoutFnType->get_parameters().push_back( alignParam );
                addOtypeParams( layoutFnType, otypeParams );

                // build function decl
                FunctionDecl *layoutDecl = buildLayoutFunctionDecl( unionDecl, functionNesting, layoutFnType );

                // calculate union layout in function body
                addExpr( layoutDecl->get_statements(), makeOp( "?=?", derefVar( sizeParam ), new ConstantExpr( Constant( sizeAlignType->clone(), "1" ) ) ) );
                addExpr( layoutDecl->get_statements(), makeOp( "?=?", derefVar( alignParam ), new ConstantExpr( Constant( sizeAlignType->clone(), "1" ) ) ) );
                for ( std::list< Declaration* >::const_iterator member = unionDecl->get_members().begin(); member != unionDecl->get_members().end(); ++member ) {
                        DeclarationWithType *dwt = dynamic_cast< DeclarationWithType * >( *member );
                        assert( dwt );
                        Type *memberType = dwt->get_type();

                        // take max member size and global size
                        addStmt( layoutDecl->get_statements(), makeAssignMax( derefVar( sizeParam ), new SizeofExpr( memberType->clone() ) ) );

                        // take max of member alignment and global alignment
                        addStmt( layoutDecl->get_statements(), makeAssignMax( derefVar( alignParam ), new AlignofExpr( memberType->clone() ) ) );
                }
                // make sure the type is end-padded to a multiple of its alignment
                addStmt( layoutDecl->get_statements(), makeAlignTo( derefVar( sizeParam ), derefVar( alignParam ) ) );

                addDeclarationAfter( layoutDecl );
                return unionDecl;
        }

        ////////////////////////////////////////// Pass1 ////////////////////////////////////////////////////

        namespace {
                std::string makePolyMonoSuffix( FunctionType * function, const TyVarMap &tyVars ) {
                        std::stringstream name;

                        // NOTE: this function previously used isPolyObj, which failed to produce
                        // the correct thing in some situations. It's not clear to me why this wasn't working.

                        // if the return type or a parameter type involved polymorphic types, then the adapter will need
                        // to take those polymorphic types as pointers. Therefore, there can be two different functions
                        // with the same mangled name, so we need to further mangle the names.
                        for ( std::list< DeclarationWithType *>::iterator retval = function->get_returnVals().begin(); retval != function->get_returnVals().end(); ++retval ) {
                                if ( isPolyType( (*retval)->get_type(), tyVars ) ) {
                                        name << "P";
                                } else {
                                        name << "M";
                                }
                        }
                        name << "_";
                        std::list< DeclarationWithType *> &paramList = function->get_parameters();
                        for ( std::list< DeclarationWithType *>::iterator arg = paramList.begin(); arg != paramList.end(); ++arg ) {
                                if ( isPolyType( (*arg)->get_type(), tyVars ) ) {
                                        name << "P";
                                } else {
                                        name << "M";
                                }
                        } // for
                        return name.str();
                }

                std::string mangleAdapterName( FunctionType * function, const TyVarMap &tyVars ) {
                        return SymTab::Mangler::mangle( function ) + makePolyMonoSuffix( function, tyVars );
                }

                std::string makeAdapterName( const std::string &mangleName ) {
                        return "_adapter" + mangleName;
                }

                Pass1::Pass1() : tempNamer( "_temp" ) {}

                DeclarationWithType *Pass1::mutate( FunctionDecl *functionDecl ) {
                        if ( functionDecl->get_statements() ) {         // empty routine body ?
                                doBeginScope();
                                scopeTyVars.beginScope();

                                DeclarationWithType *oldRetval = retval;

                                // process polymorphic return value
                                retval = nullptr;
                                if ( isDynRet( functionDecl->get_functionType() ) && functionDecl->get_linkage() != LinkageSpec::C ) {
                                        retval = functionDecl->get_functionType()->get_returnVals().front();

                                        // give names to unnamed return values
                                        if ( retval->get_name() == "" ) {
                                                retval->set_name( "_retparm" );
                                                retval->set_linkage( LinkageSpec::C );
                                        } // if
                                } // if

                                FunctionType *functionType = functionDecl->get_functionType();
                                makeTyVarMap( functionDecl->get_functionType(), scopeTyVars );

                                std::list< DeclarationWithType *> &paramList = functionType->get_parameters();
                                std::list< FunctionType *> functions;
                                for ( Type::ForallList::iterator tyVar = functionType->get_forall().begin(); tyVar != functionType->get_forall().end(); ++tyVar ) {
                                        for ( std::list< DeclarationWithType *>::iterator assert = (*tyVar)->get_assertions().begin(); assert != (*tyVar)->get_assertions().end(); ++assert ) {
                                                findFunction( (*assert)->get_type(), functions, scopeTyVars, needsAdapter );
                                        } // for
                                } // for
                                for ( std::list< DeclarationWithType *>::iterator arg = paramList.begin(); arg != paramList.end(); ++arg ) {
                                        findFunction( (*arg)->get_type(), functions, scopeTyVars, needsAdapter );
                                } // for

                                for ( std::list< FunctionType *>::iterator funType = functions.begin(); funType != functions.end(); ++funType ) {
                                        std::string mangleName = mangleAdapterName( *funType, scopeTyVars );
                                        if ( adapters.find( mangleName ) == adapters.end() ) {
                                                std::string adapterName = makeAdapterName( mangleName );
                                                adapters.insert( std::pair< std::string, DeclarationWithType *>( mangleName, new ObjectDecl( adapterName, DeclarationNode::NoStorageClass, LinkageSpec::C, nullptr, new PointerType( Type::Qualifiers(), makeAdapterType( *funType, scopeTyVars ) ), nullptr ) ) );
                                        } // if
                                } // for

                                functionDecl->set_statements( functionDecl->get_statements()->acceptMutator( *this ) );

                                scopeTyVars.endScope();
                                retval = oldRetval;
                                doEndScope();
                        } // if
                        return functionDecl;
                }

                TypeDecl *Pass1::mutate( TypeDecl *typeDecl ) {
                        addToTyVarMap( typeDecl, scopeTyVars );
                        return Mutator::mutate( typeDecl );
                }

                Expression *Pass1::mutate( CommaExpr *commaExpr ) {
                        // Attempting to find application expressions that were mutated by the copy constructor passes
                        // to use an explicit return variable, so that the variable can be reused as a parameter to the
                        // call rather than creating a new temp variable. Previously this step was an optimization, but
                        // with the introduction of tuples and UniqueExprs, it is necessary to ensure that they use the same variable.
                        // Essentially, looking for pattern: (x=f(...), x)
                        // To compound the issue, the right side can be *x, etc. because of lvalue-returning functions
                        if ( UntypedExpr * assign = dynamic_cast< UntypedExpr * >( commaExpr->get_arg1() ) ) {
                                if ( InitTweak::isAssignment( InitTweak::getFunctionName( assign ) ) ) {
                                        assert( assign->get_args().size() == 2 );
                                        if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( assign->get_args().back() ) ) {
                                                // first argument is assignable, so it must be an lvalue, so it should be legal to take its address.
                                                retVals[appExpr] = assign->get_args().front();
                                        }
                                }
                        }

                        commaExpr->set_arg1( maybeMutate( commaExpr->get_arg1(), *this ) );
                        commaExpr->set_arg2( maybeMutate( commaExpr->get_arg2(), *this ) );
                        return commaExpr;
                }

                Expression *Pass1::mutate( ConditionalExpr *condExpr ) {
                        condExpr->set_arg1( maybeMutate( condExpr->get_arg1(), *this ) );
                        condExpr->set_arg2( maybeMutate( condExpr->get_arg2(), *this ) );
                        condExpr->set_arg3( maybeMutate( condExpr->get_arg3(), *this ) );
                        return condExpr;

                }

                void Pass1::passArgTypeVars( ApplicationExpr *appExpr, Type *parmType, Type *argBaseType, std::list< Expression *>::iterator &arg, const TyVarMap &exprTyVars, std::set< std::string > &seenTypes ) {
                        Type *polyType = isPolyType( parmType, exprTyVars );
                        if ( polyType && ! dynamic_cast< TypeInstType* >( polyType ) ) {
                                std::string typeName = mangleType( polyType );
                                if ( seenTypes.count( typeName ) ) return;

                                arg = appExpr->get_args().insert( arg, new SizeofExpr( argBaseType->clone() ) );
                                arg++;
                                arg = appExpr->get_args().insert( arg, new AlignofExpr( argBaseType->clone() ) );
                                arg++;
                                if ( dynamic_cast< StructInstType* >( polyType ) ) {
                                        if ( StructInstType *argBaseStructType = dynamic_cast< StructInstType* >( argBaseType ) ) {
                                                // zero-length arrays are forbidden by C, so don't pass offset for empty struct
                                                if ( ! argBaseStructType->get_baseStruct()->get_members().empty() ) {
                                                        arg = appExpr->get_args().insert( arg, new OffsetPackExpr( argBaseStructType->clone() ) );
                                                        arg++;
                                                }
                                        } else {
                                                throw SemanticError( "Cannot pass non-struct type for generic struct" );
                                        }
                                }

                                seenTypes.insert( typeName );
                        }
                }

                void Pass1::passTypeVars( ApplicationExpr *appExpr, Type *polyRetType, std::list< Expression *>::iterator &arg, const TyVarMap &exprTyVars ) {
                        // pass size/align for type variables
                        for ( TyVarMap::const_iterator tyParm = exprTyVars.begin(); tyParm != exprTyVars.end(); ++tyParm ) {
                                ResolvExpr::EqvClass eqvClass;
                                assert( env );
                                if ( tyParm->second.isComplete ) {
                                        Type *concrete = env->lookup( tyParm->first );
                                        if ( concrete ) {
                                                arg = appExpr->get_args().insert( arg, new SizeofExpr( concrete->clone() ) );
                                                arg++;
                                                arg = appExpr->get_args().insert( arg, new AlignofExpr( concrete->clone() ) );
                                                arg++;
                                        } else {
                                                // xxx - should this be an assertion?
                                                std::string x = env ? toString( *env ) : "missing env";
                                                throw SemanticError( x + "\n" + "unbound type variable: " + tyParm->first + " in application ", appExpr );
                                        } // if
                                } // if
                        } // for

                        // add size/align for generic types to parameter list
                        if ( ! appExpr->get_function()->has_result() ) return;
                        FunctionType *funcType = getFunctionType( appExpr->get_function()->get_result() );
                        assert( funcType );

                        std::list< DeclarationWithType* >::const_iterator fnParm = funcType->get_parameters().begin();
                        std::list< Expression* >::const_iterator fnArg = arg;
                        std::set< std::string > seenTypes; ///< names for generic types we've seen

                        // a polymorphic return type may need to be added to the argument list
                        if ( polyRetType ) {
                                Type *concRetType = replaceWithConcrete( appExpr, polyRetType );
                                passArgTypeVars( appExpr, polyRetType, concRetType, arg, exprTyVars, seenTypes );
                                ++fnArg; // skip the return parameter in the argument list
                        }

                        // add type information args for presently unseen types in parameter list
                        for ( ; fnParm != funcType->get_parameters().end() && fnArg != appExpr->get_args().end(); ++fnParm, ++fnArg ) {
                                if ( ! (*fnArg)->get_result() ) continue;
                                Type * argType = (*fnArg)->get_result();
                                passArgTypeVars( appExpr, (*fnParm)->get_type(), argType, arg, exprTyVars, seenTypes );
                        }
                }

                ObjectDecl *Pass1::makeTemporary( Type *type ) {
                        ObjectDecl *newObj = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, type, 0 );
                        stmtsToAdd.push_back( new DeclStmt( noLabels, newObj ) );
                        return newObj;
                }

                Expression *Pass1::addRetParam( ApplicationExpr *appExpr, FunctionType *function, Type *retType, std::list< Expression *>::iterator &arg ) {
                        // Create temporary to hold return value of polymorphic function and produce that temporary as a result
                        // using a comma expression.
                        assert( retType );

                        Expression * paramExpr = nullptr;
                        // try to use existing return value parameter if it exists, otherwise create a new temporary
                        if ( retVals.count( appExpr ) ) {
                                paramExpr = retVals[appExpr]->clone();
                        } else {
                                ObjectDecl *newObj = makeTemporary( retType->clone() );
                                paramExpr = new VariableExpr( newObj );
                        }
                        Expression * retExpr = paramExpr->clone();

                        // If the type of the temporary is not polymorphic, box temporary by taking its address;
                        // otherwise the temporary is already boxed and can be used directly.
                        if ( ! isPolyType( paramExpr->get_result(), scopeTyVars, env ) ) {
                                paramExpr = new AddressExpr( paramExpr );
                        } // if
                        arg = appExpr->get_args().insert( arg, paramExpr ); // add argument to function call
                        arg++;
                        // Build a comma expression to call the function and emulate a normal return.
                        CommaExpr *commaExpr = new CommaExpr( appExpr, retExpr );
                        commaExpr->set_env( appExpr->get_env() );
                        appExpr->set_env( 0 );
                        return commaExpr;
                }

                void Pass1::replaceParametersWithConcrete( ApplicationExpr *appExpr, std::list< Expression* >& params ) {
                        for ( std::list< Expression* >::iterator param = params.begin(); param != params.end(); ++param ) {
                                TypeExpr *paramType = dynamic_cast< TypeExpr* >( *param );
                                assert(paramType && "Aggregate parameters should be type expressions");
                                paramType->set_type( replaceWithConcrete( appExpr, paramType->get_type(), false ) );
                        }
                }

                Type *Pass1::replaceWithConcrete( ApplicationExpr *appExpr, Type *type, bool doClone ) {
                        if ( TypeInstType *typeInst = dynamic_cast< TypeInstType * >( type ) ) {
                                Type *concrete = env->lookup( typeInst->get_name() );
                                if ( concrete == 0 ) {
                                        // xxx - should this be an assertion?
                                        std::string x = env ? toString( *env ) : "missing env";
                                        throw SemanticError( x + "\n" + "Unbound type variable " + typeInst->get_name() + " in ", appExpr );
                                } // if
                                return concrete;
                        } else if ( StructInstType *structType = dynamic_cast< StructInstType* >( type ) ) {
                                if ( doClone ) {
                                        structType = structType->clone();
                                }
                                replaceParametersWithConcrete( appExpr, structType->get_parameters() );
                                return structType;
                        } else if ( UnionInstType *unionType = dynamic_cast< UnionInstType* >( type ) ) {
                                if ( doClone ) {
                                        unionType = unionType->clone();
                                }
                                replaceParametersWithConcrete( appExpr, unionType->get_parameters() );
                                return unionType;
                        }
                        return type;
                }

                Expression *Pass1::addDynRetParam( ApplicationExpr *appExpr, FunctionType *function, Type *dynType, std::list< Expression *>::iterator &arg ) {
                        assert( env );
                        Type *concrete = replaceWithConcrete( appExpr, dynType );
                        // add out-parameter for return value
                        return addRetParam( appExpr, function, concrete, arg );
                }

                Expression *Pass1::applyAdapter( ApplicationExpr *appExpr, FunctionType *function, std::list< Expression *>::iterator &arg, const TyVarMap &tyVars ) {
                        Expression *ret = appExpr;
//                      if ( ! function->get_returnVals().empty() && isPolyType( function->get_returnVals().front()->get_type(), tyVars ) ) {
                        if ( isDynRet( function, tyVars ) ) {
                                ret = addRetParam( appExpr, function, function->get_returnVals().front()->get_type(), arg );
                        } // if
                        std::string mangleName = mangleAdapterName( function, tyVars );
                        std::string adapterName = makeAdapterName( mangleName );

                        // cast adaptee to void (*)(), since it may have any type inside a polymorphic function
                        Type * adapteeType = new PointerType( Type::Qualifiers(), new FunctionType( Type::Qualifiers(), true ) );
                        appExpr->get_args().push_front( new CastExpr( appExpr->get_function(), adapteeType ) );
                        appExpr->set_function( new NameExpr( adapterName ) ); // xxx - result is never set on NameExpr

                        return ret;
                }

                void Pass1::boxParam( Type *param, Expression *&arg, const TyVarMap &exprTyVars ) {
                        assert( arg->has_result() );
                        if ( isPolyType( param, exprTyVars ) ) {
                                if ( isPolyType( arg->get_result() ) ) {
                                        // if the argument's type is polymorphic, we don't need to box again!
                                        return;
                                } else if ( arg->get_result()->get_isLvalue() ) {
                                        // VariableExpr and MemberExpr are lvalues; need to check this isn't coming from the second arg of a comma expression though (not an lvalue)
                                        // xxx - need to test that this code is still reachable
                                        if ( CommaExpr *commaArg = dynamic_cast< CommaExpr* >( arg ) ) {
                                                commaArg->set_arg2( new AddressExpr( commaArg->get_arg2() ) );
                                        } else {
                                                arg = new AddressExpr( arg );
                                        }
                                } else {
                                        // use type computed in unification to declare boxed variables
                                        Type * newType = param->clone();
                                        if ( env ) env->apply( newType );
                                        ObjectDecl *newObj = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, newType, 0 );
                                        newObj->get_type()->get_qualifiers() = Type::Qualifiers(); // TODO: is this right???
                                        stmtsToAdd.push_back( new DeclStmt( noLabels, newObj ) );
                                        UntypedExpr *assign = new UntypedExpr( new NameExpr( "?=?" ) );
                                        assign->get_args().push_back( new VariableExpr( newObj ) );
                                        assign->get_args().push_back( arg );
                                        stmtsToAdd.push_back( new ExprStmt( noLabels, assign ) );
                                        arg = new AddressExpr( new VariableExpr( newObj ) );
                                } // if
                        } // if
                }

                /// cast parameters to polymorphic functions so that types are replaced with
                /// void * if they are type parameters in the formal type.
                /// this gets rid of warnings from gcc.
                void addCast( Expression *&actual, Type *formal, const TyVarMap &tyVars ) {
                        if ( getFunctionType( formal ) ) {
                                Type * newType = formal->clone();
                                newType = ScrubTyVars::scrub( newType, tyVars );
                                actual = new CastExpr( actual, newType );
                        } // if
                }

                void Pass1::boxParams( ApplicationExpr *appExpr, FunctionType *function, std::list< Expression *>::iterator &arg, const TyVarMap &exprTyVars ) {
                        for ( std::list< DeclarationWithType *>::const_iterator param = function->get_parameters().begin(); param != function->get_parameters().end(); ++param, ++arg ) {
                                assert( arg != appExpr->get_args().end() );
                                addCast( *arg, (*param)->get_type(), exprTyVars );
                                boxParam( (*param)->get_type(), *arg, exprTyVars );
                        } // for
                }

                void Pass1::addInferredParams( ApplicationExpr *appExpr, FunctionType *functionType, std::list< Expression *>::iterator &arg, const TyVarMap &tyVars ) {
                        std::list< Expression *>::iterator cur = arg;
                        for ( Type::ForallList::iterator tyVar = functionType->get_forall().begin(); tyVar != functionType->get_forall().end(); ++tyVar ) {
                                for ( std::list< DeclarationWithType *>::iterator assert = (*tyVar)->get_assertions().begin(); assert != (*tyVar)->get_assertions().end(); ++assert ) {
                                        InferredParams::const_iterator inferParam = appExpr->get_inferParams().find( (*assert)->get_uniqueId() );
                                        if ( inferParam == appExpr->get_inferParams().end() ) {
                                                std::cerr << "looking for assertion: " << (*assert) << std::endl << appExpr << std::endl;
                                        }
                                        assertf( inferParam != appExpr->get_inferParams().end(), "NOTE: Explicit casts of polymorphic functions to compatible monomorphic functions are currently unsupported" );
                                        Expression *newExpr = inferParam->second.expr->clone();
                                        addCast( newExpr, (*assert)->get_type(), tyVars );
                                        boxParam( (*assert)->get_type(), newExpr, tyVars );
                                        appExpr->get_args().insert( cur, newExpr );
                                } // for
                        } // for
                }

                void makeRetParm( FunctionType *funcType ) {
                        DeclarationWithType *retParm = funcType->get_returnVals().front();

                        // make a new parameter that is a pointer to the type of the old return value
                        retParm->set_type( new PointerType( Type::Qualifiers(), retParm->get_type() ) );
                        funcType->get_parameters().push_front( retParm );

                        // we don't need the return value any more
                        funcType->get_returnVals().clear();
                }

                FunctionType *makeAdapterType( FunctionType *adaptee, const TyVarMap &tyVars ) {
                        // actually make the adapter type
                        FunctionType *adapter = adaptee->clone();
//                      if ( ! adapter->get_returnVals().empty() && isPolyType( adapter->get_returnVals().front()->get_type(), tyVars ) ) {
                        if ( isDynRet( adapter, tyVars ) ) {
                                makeRetParm( adapter );
                        } // if
                        adapter->get_parameters().push_front( new ObjectDecl( "", DeclarationNode::NoStorageClass, LinkageSpec::C, 0, new PointerType( Type::Qualifiers(), new FunctionType( Type::Qualifiers(), true ) ), 0 ) );
                        return adapter;
                }

                Expression *makeAdapterArg( DeclarationWithType *param, DeclarationWithType *arg, DeclarationWithType *realParam, const TyVarMap &tyVars ) {
                        assert( param );
                        assert( arg );
                        if ( isPolyType( realParam->get_type(), tyVars ) ) {
                                if ( ! isPolyType( arg->get_type() ) ) {
                                        UntypedExpr *deref = new UntypedExpr( new NameExpr( "*?" ) );
                                        deref->get_args().push_back( new CastExpr( new VariableExpr( param ), new PointerType( Type::Qualifiers(), arg->get_type()->clone() ) ) );
                                        deref->set_result( arg->get_type()->clone() );
                                        return deref;
                                } // if
                        } // if
                        return new VariableExpr( param );
                }

                void addAdapterParams( ApplicationExpr *adapteeApp, std::list< DeclarationWithType *>::iterator arg, std::list< DeclarationWithType *>::iterator param, std::list< DeclarationWithType *>::iterator paramEnd, std::list< DeclarationWithType *>::iterator realParam, const TyVarMap &tyVars ) {
                        UniqueName paramNamer( "_p" );
                        for ( ; param != paramEnd; ++param, ++arg, ++realParam ) {
                                if ( (*param)->get_name() == "" ) {
                                        (*param)->set_name( paramNamer.newName() );
                                        (*param)->set_linkage( LinkageSpec::C );
                                } // if
                                adapteeApp->get_args().push_back( makeAdapterArg( *param, *arg, *realParam, tyVars ) );
                        } // for
                }

                FunctionDecl *Pass1::makeAdapter( FunctionType *adaptee, FunctionType *realType, const std::string &mangleName, const TyVarMap &tyVars ) {
                        FunctionType *adapterType = makeAdapterType( adaptee, tyVars );
                        adapterType = ScrubTyVars::scrub( adapterType, tyVars );
                        DeclarationWithType *adapteeDecl = adapterType->get_parameters().front();
                        adapteeDecl->set_name( "_adaptee" );
                        ApplicationExpr *adapteeApp = new ApplicationExpr( new CastExpr( new VariableExpr( adapteeDecl ), new PointerType( Type::Qualifiers(), realType ) ) );
                        Statement *bodyStmt;

                        Type::ForallList::iterator tyArg = realType->get_forall().begin();
                        Type::ForallList::iterator tyParam = adapterType->get_forall().begin();
                        Type::ForallList::iterator realTyParam = adaptee->get_forall().begin();
                        for ( ; tyParam != adapterType->get_forall().end(); ++tyArg, ++tyParam, ++realTyParam ) {
                                assert( tyArg != realType->get_forall().end() );
                                std::list< DeclarationWithType *>::iterator assertArg = (*tyArg)->get_assertions().begin();
                                std::list< DeclarationWithType *>::iterator assertParam = (*tyParam)->get_assertions().begin();
                                std::list< DeclarationWithType *>::iterator realAssertParam = (*realTyParam)->get_assertions().begin();
                                for ( ; assertParam != (*tyParam)->get_assertions().end(); ++assertArg, ++assertParam, ++realAssertParam ) {
                                        assert( assertArg != (*tyArg)->get_assertions().end() );
                                        adapteeApp->get_args().push_back( makeAdapterArg( *assertParam, *assertArg, *realAssertParam, tyVars ) );
                                } // for
                        } // for

                        std::list< DeclarationWithType *>::iterator arg = realType->get_parameters().begin();
                        std::list< DeclarationWithType *>::iterator param = adapterType->get_parameters().begin();
                        std::list< DeclarationWithType *>::iterator realParam = adaptee->get_parameters().begin();
                        param++;                // skip adaptee parameter in the adapter type
                        if ( realType->get_returnVals().empty() ) {
                                // void return
                                addAdapterParams( adapteeApp, arg, param, adapterType->get_parameters().end(), realParam, tyVars );
                                bodyStmt = new ExprStmt( noLabels, adapteeApp );
//                      } else if ( isPolyType( adaptee->get_returnVals().front()->get_type(), tyVars ) ) {
                        } else if ( isDynType( adaptee->get_returnVals().front()->get_type(), tyVars ) ) {
                                // return type T
                                if ( (*param)->get_name() == "" ) {
                                        (*param)->set_name( "_ret" );
                                        (*param)->set_linkage( LinkageSpec::C );
                                } // if
                                UntypedExpr *assign = new UntypedExpr( new NameExpr( "?=?" ) );
                                UntypedExpr *deref = new UntypedExpr( new NameExpr( "*?" ) );
                                deref->get_args().push_back( new CastExpr( new VariableExpr( *param++ ), new PointerType( Type::Qualifiers(), realType->get_returnVals().front()->get_type()->clone() ) ) );
                                assign->get_args().push_back( deref );
                                addAdapterParams( adapteeApp, arg, param, adapterType->get_parameters().end(), realParam, tyVars );
                                assign->get_args().push_back( adapteeApp );
                                bodyStmt = new ExprStmt( noLabels, assign );
                        } else {
                                // adapter for a function that returns a monomorphic value
                                addAdapterParams( adapteeApp, arg, param, adapterType->get_parameters().end(), realParam, tyVars );
                                bodyStmt = new ReturnStmt( noLabels, adapteeApp );
                        } // if
                        CompoundStmt *adapterBody = new CompoundStmt( noLabels );
                        adapterBody->get_kids().push_back( bodyStmt );
                        std::string adapterName = makeAdapterName( mangleName );
                        return new FunctionDecl( adapterName, DeclarationNode::NoStorageClass, LinkageSpec::C, adapterType, adapterBody, false, false );
                }

                void Pass1::passAdapters( ApplicationExpr * appExpr, FunctionType * functionType, const TyVarMap & exprTyVars ) {
                        // collect a list of function types passed as parameters or implicit parameters (assertions)
                        std::list< DeclarationWithType *> &paramList = functionType->get_parameters();
                        std::list< FunctionType *> functions;
                        for ( Type::ForallList::iterator tyVar = functionType->get_forall().begin(); tyVar != functionType->get_forall().end(); ++tyVar ) {
                                for ( std::list< DeclarationWithType *>::iterator assert = (*tyVar)->get_assertions().begin(); assert != (*tyVar)->get_assertions().end(); ++assert ) {
                                        findFunction( (*assert)->get_type(), functions, exprTyVars, needsAdapter );
                                } // for
                        } // for
                        for ( std::list< DeclarationWithType *>::iterator arg = paramList.begin(); arg != paramList.end(); ++arg ) {
                                findFunction( (*arg)->get_type(), functions, exprTyVars, needsAdapter );
                        } // for

                        // parameter function types for which an appropriate adapter has been generated.  we cannot use the types
                        // after applying substitutions, since two different parameter types may be unified to the same type
                        std::set< std::string > adaptersDone;

                        for ( std::list< FunctionType *>::iterator funType = functions.begin(); funType != functions.end(); ++funType ) {
                                FunctionType *originalFunction = (*funType)->clone();
                                FunctionType *realFunction = (*funType)->clone();
                                std::string mangleName = SymTab::Mangler::mangle( realFunction );

                                // only attempt to create an adapter or pass one as a parameter if we haven't already done so for this
                                // pre-substitution parameter function type.
                                if ( adaptersDone.find( mangleName ) == adaptersDone.end() ) {
                                        adaptersDone.insert( adaptersDone.begin(), mangleName );

                                        // apply substitution to type variables to figure out what the adapter's type should look like
                                        assert( env );
                                        env->apply( realFunction );
                                        mangleName = SymTab::Mangler::mangle( realFunction );
                                        mangleName += makePolyMonoSuffix( originalFunction, exprTyVars );

                                        typedef ScopedMap< std::string, DeclarationWithType* >::iterator AdapterIter;
                                        AdapterIter adapter = adapters.find( mangleName );
                                        if ( adapter == adapters.end() ) {
                                                // adapter has not been created yet in the current scope, so define it
                                                FunctionDecl *newAdapter = makeAdapter( *funType, realFunction, mangleName, exprTyVars );
                                                std::pair< AdapterIter, bool > answer = adapters.insert( std::pair< std::string, DeclarationWithType *>( mangleName, newAdapter ) );
                                                adapter = answer.first;
                                                stmtsToAdd.push_back( new DeclStmt( noLabels, newAdapter ) );
                                        } // if
                                        assert( adapter != adapters.end() );

                                        // add the appropriate adapter as a parameter
                                        appExpr->get_args().push_front( new VariableExpr( adapter->second ) );
                                } // if
                        } // for
                } // passAdapters

                Expression *makeIncrDecrExpr( ApplicationExpr *appExpr, Type *polyType, bool isIncr ) {
                        NameExpr *opExpr;
                        if ( isIncr ) {
                                opExpr = new NameExpr( "?+=?" );
                        } else {
                                opExpr = new NameExpr( "?-=?" );
                        } // if
                        UntypedExpr *addAssign = new UntypedExpr( opExpr );
                        if ( AddressExpr *address = dynamic_cast< AddressExpr *>( appExpr->get_args().front() ) ) {
                                addAssign->get_args().push_back( address->get_arg() );
                        } else {
                                addAssign->get_args().push_back( appExpr->get_args().front() );
                        } // if
                        addAssign->get_args().push_back( new NameExpr( sizeofName( mangleType( polyType ) ) ) );
                        addAssign->set_result( appExpr->get_result()->clone() );
                        if ( appExpr->get_env() ) {
                                addAssign->set_env( appExpr->get_env() );
                                appExpr->set_env( 0 );
                        } // if
                        appExpr->get_args().clear();
                        delete appExpr;
                        return addAssign;
                }

                Expression *Pass1::handleIntrinsics( ApplicationExpr *appExpr ) {
                        if ( VariableExpr *varExpr = dynamic_cast< VariableExpr *>( appExpr->get_function() ) ) {
                                if ( varExpr->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
                                        if ( varExpr->get_var()->get_name() == "?[?]" ) {
                                                assert( appExpr->has_result() );
                                                assert( appExpr->get_args().size() == 2 );
                                                Type *baseType1 = isPolyPtr( appExpr->get_args().front()->get_result(), scopeTyVars, env );
                                                Type *baseType2 = isPolyPtr( appExpr->get_args().back()->get_result(), scopeTyVars, env );
                                                assert( ! baseType1 || ! baseType2 ); // the arguments cannot both be polymorphic pointers
                                                UntypedExpr *ret = 0;
                                                if ( baseType1 || baseType2 ) { // one of the arguments is a polymorphic pointer
                                                        ret = new UntypedExpr( new NameExpr( "?+?" ) );
                                                } // if
                                                if ( baseType1 ) {
                                                        UntypedExpr *multiply = new UntypedExpr( new NameExpr( "?*?" ) );
                                                        multiply->get_args().push_back( appExpr->get_args().back() );
                                                        multiply->get_args().push_back( new SizeofExpr( baseType1->clone() ) );
                                                        ret->get_args().push_back( appExpr->get_args().front() );
                                                        ret->get_args().push_back( multiply );
                                                } else if ( baseType2 ) {
                                                        UntypedExpr *multiply = new UntypedExpr( new NameExpr( "?*?" ) );
                                                        multiply->get_args().push_back( appExpr->get_args().front() );
                                                        multiply->get_args().push_back( new SizeofExpr( baseType2->clone() ) );
                                                        ret->get_args().push_back( multiply );
                                                        ret->get_args().push_back( appExpr->get_args().back() );
                                                } // if
                                                if ( baseType1 || baseType2 ) {
                                                        ret->set_result( appExpr->get_result()->clone() );
                                                        if ( appExpr->get_env() ) {
                                                                ret->set_env( appExpr->get_env() );
                                                                appExpr->set_env( 0 );
                                                        } // if
                                                        appExpr->get_args().clear();
                                                        delete appExpr;
                                                        return ret;
                                                } // if
                                        } else if ( varExpr->get_var()->get_name() == "*?" ) {
                                                assert( appExpr->has_result() );
                                                assert( ! appExpr->get_args().empty() );
                                                if ( isPolyType( appExpr->get_result(), scopeTyVars, env ) ) {
                                                        Expression *ret = appExpr->get_args().front();
                                                        delete ret->get_result();
                                                        ret->set_result( appExpr->get_result()->clone() );
                                                        if ( appExpr->get_env() ) {
                                                                ret->set_env( appExpr->get_env() );
                                                                appExpr->set_env( 0 );
                                                        } // if
                                                        appExpr->get_args().clear();
                                                        delete appExpr;
                                                        return ret;
                                                } // if
                                        } else if ( varExpr->get_var()->get_name() == "?++" || varExpr->get_var()->get_name() == "?--" ) {
                                                assert( appExpr->has_result() );
                                                assert( appExpr->get_args().size() == 1 );
                                                if ( Type *baseType = isPolyPtr( appExpr->get_result(), scopeTyVars, env ) ) {
                                                        Type *tempType = appExpr->get_result()->clone();
                                                        if ( env ) {
                                                                env->apply( tempType );
                                                        } // if
                                                        ObjectDecl *newObj = makeTemporary( tempType );
                                                        VariableExpr *tempExpr = new VariableExpr( newObj );
                                                        UntypedExpr *assignExpr = new UntypedExpr( new NameExpr( "?=?" ) );
                                                        assignExpr->get_args().push_back( tempExpr->clone() );
                                                        if ( AddressExpr *address = dynamic_cast< AddressExpr *>( appExpr->get_args().front() ) ) {
                                                                assignExpr->get_args().push_back( address->get_arg()->clone() );
                                                        } else {
                                                                assignExpr->get_args().push_back( appExpr->get_args().front()->clone() );
                                                        } // if
                                                        CommaExpr *firstComma = new CommaExpr( assignExpr, makeIncrDecrExpr( appExpr, baseType, varExpr->get_var()->get_name() == "?++" ) );
                                                        return new CommaExpr( firstComma, tempExpr );
                                                } // if
                                        } else if ( varExpr->get_var()->get_name() == "++?" || varExpr->get_var()->get_name() == "--?" ) {
                                                assert( appExpr->has_result() );
                                                assert( appExpr->get_args().size() == 1 );
                                                if ( Type *baseType = isPolyPtr( appExpr->get_result(), scopeTyVars, env ) ) {
                                                        return makeIncrDecrExpr( appExpr, baseType, varExpr->get_var()->get_name() == "++?" );
                                                } // if
                                        } else if ( varExpr->get_var()->get_name() == "?+?" || varExpr->get_var()->get_name() == "?-?" ) {
                                                assert( appExpr->has_result() );
                                                assert( appExpr->get_args().size() == 2 );
                                                Type *baseType1 = isPolyPtr( appExpr->get_args().front()->get_result(), scopeTyVars, env );
                                                Type *baseType2 = isPolyPtr( appExpr->get_args().back()->get_result(), scopeTyVars, env );
                                                if ( baseType1 && baseType2 ) {
                                                        UntypedExpr *divide = new UntypedExpr( new NameExpr( "?/?" ) );
                                                        divide->get_args().push_back( appExpr );
                                                        divide->get_args().push_back( new SizeofExpr( baseType1->clone() ) );
                                                        divide->set_result( appExpr->get_result()->clone() );
                                                        if ( appExpr->get_env() ) {
                                                                divide->set_env( appExpr->get_env() );
                                                                appExpr->set_env( 0 );
                                                        } // if
                                                        return divide;
                                                } else if ( baseType1 ) {
                                                        UntypedExpr *multiply = new UntypedExpr( new NameExpr( "?*?" ) );
                                                        multiply->get_args().push_back( appExpr->get_args().back() );
                                                        multiply->get_args().push_back( new SizeofExpr( baseType1->clone() ) );
                                                        appExpr->get_args().back() = multiply;
                                                } else if ( baseType2 ) {
                                                        UntypedExpr *multiply = new UntypedExpr( new NameExpr( "?*?" ) );
                                                        multiply->get_args().push_back( appExpr->get_args().front() );
                                                        multiply->get_args().push_back( new SizeofExpr( baseType2->clone() ) );
                                                        appExpr->get_args().front() = multiply;
                                                } // if
                                        } else if ( varExpr->get_var()->get_name() == "?+=?" || varExpr->get_var()->get_name() == "?-=?" ) {
                                                assert( appExpr->has_result() );
                                                assert( appExpr->get_args().size() == 2 );
                                                Type *baseType = isPolyPtr( appExpr->get_result(), scopeTyVars, env );
                                                if ( baseType ) {
                                                        UntypedExpr *multiply = new UntypedExpr( new NameExpr( "?*?" ) );
                                                        multiply->get_args().push_back( appExpr->get_args().back() );
                                                        multiply->get_args().push_back( new SizeofExpr( baseType->clone() ) );
                                                        appExpr->get_args().back() = multiply;
                                                } // if
                                        } // if
                                        return appExpr;
                                } // if
                        } // if
                        return 0;
                }

                Expression *Pass1::mutate( ApplicationExpr *appExpr ) {
                        // std::cerr << "mutate appExpr: ";
                        // for ( TyVarMap::iterator i = scopeTyVars.begin(); i != scopeTyVars.end(); ++i ) {
                        //      std::cerr << i->first << " ";
                        // }
                        // std::cerr << "\n";
                        appExpr->get_function()->acceptMutator( *this );
                        mutateAll( appExpr->get_args(), *this );

                        assert( appExpr->get_function()->has_result() );
                        PointerType *pointer = safe_dynamic_cast< PointerType *>( appExpr->get_function()->get_result() );
                        FunctionType *function = safe_dynamic_cast< FunctionType *>( pointer->get_base() );

                        if ( Expression *newExpr = handleIntrinsics( appExpr ) ) {
                                return newExpr;
                        } // if

                        Expression *ret = appExpr;

                        std::list< Expression *>::iterator arg = appExpr->get_args().begin();
                        std::list< Expression *>::iterator paramBegin = appExpr->get_args().begin();

                        TyVarMap exprTyVars( TypeDecl::Data{} );
                        makeTyVarMap( function, exprTyVars ); // xxx - should this take into account the variables already bound in scopeTyVars (i.e. remove them from exprTyVars?)
                        ReferenceToType *dynRetType = isDynRet( function, exprTyVars );
                        Type *concRetType = appExpr->get_result()->isVoid() ? nullptr : appExpr->get_result();// ?: dynRetType; // xxx - is concRetType a good name?

                        if ( dynRetType ) {
                                ret = addDynRetParam( appExpr, function, concRetType, arg ); // xxx - used to use dynRetType instead of concRetType
                        } else if ( needsAdapter( function, scopeTyVars ) && ! needsAdapter( function, exprTyVars) ) { // xxx - exprTyVars is used above...?
                                // xxx - the ! needsAdapter check may be incorrect. It seems there is some situation where an adapter is applied where it shouldn't be, and this fixes it for some cases. More investigation is needed.

                                // std::cerr << "needs adapter: ";
                                // printTyVarMap( std::cerr, scopeTyVars );
                                // std::cerr << *env << std::endl;
                                // change the application so it calls the adapter rather than the passed function
                                ret = applyAdapter( appExpr, function, arg, scopeTyVars );
                        } // if
                        arg = appExpr->get_args().begin();

                        passTypeVars( appExpr, concRetType, arg, exprTyVars ); // xxx - used to use dynRetType instead of concRetType; this changed so that the correct type paramaters are passed for return types (it should be the concrete type's parameters, not the formal type's)
                        addInferredParams( appExpr, function, arg, exprTyVars );

                        arg = paramBegin;

                        boxParams( appExpr, function, arg, exprTyVars );
                        passAdapters( appExpr, function, exprTyVars );

                        return ret;
                }

                Expression *Pass1::mutate( UntypedExpr *expr ) {
                        if ( expr->has_result() && isPolyType( expr->get_result(), scopeTyVars, env ) ) {
                                if ( NameExpr *name = dynamic_cast< NameExpr *>( expr->get_function() ) ) {
                                        if ( name->get_name() == "*?" ) {
                                                Expression *ret = expr->get_args().front();
                                                expr->get_args().clear();
                                                delete expr;
                                                return ret->acceptMutator( *this );
                                        } // if
                                } // if
                        } // if
                        return PolyMutator::mutate( expr );
                }

                Expression *Pass1::mutate( AddressExpr *addrExpr ) {
                        assert( addrExpr->get_arg()->has_result() && ! addrExpr->get_arg()->get_result()->isVoid() );

                        bool needs = false;
                        if ( UntypedExpr *expr = dynamic_cast< UntypedExpr *>( addrExpr->get_arg() ) ) {
                                if ( expr->has_result() && isPolyType( expr->get_result(), scopeTyVars, env ) ) {
                                        if ( NameExpr *name = dynamic_cast< NameExpr *>( expr->get_function() ) ) {
                                                if ( name->get_name() == "*?" ) {
                                                        if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * >( expr->get_args().front() ) ) {
                                                                assert( appExpr->get_function()->has_result() );
                                                                PointerType *pointer = safe_dynamic_cast< PointerType *>( appExpr->get_function()->get_result() );
                                                                FunctionType *function = safe_dynamic_cast< FunctionType *>( pointer->get_base() );
                                                                needs = needsAdapter( function, scopeTyVars );
                                                        } // if
                                                } // if
                                        } // if
                                } // if
                        } // if
                        // isPolyType check needs to happen before mutating addrExpr arg, so pull it forward
                        // out of the if condition.
                        bool polytype = isPolyType( addrExpr->get_arg()->get_result(), scopeTyVars, env );
                        addrExpr->set_arg( mutateExpression( addrExpr->get_arg() ) );
                        if ( polytype || needs ) {
                                Expression *ret = addrExpr->get_arg();
                                delete ret->get_result();
                                ret->set_result( addrExpr->get_result()->clone() );
                                addrExpr->set_arg( 0 );
                                delete addrExpr;
                                return ret;
                        } else {
                                return addrExpr;
                        } // if
                }

                Statement * Pass1::mutate( ReturnStmt *returnStmt ) {
                        // maybe need access to the env when mutating the expr
                        if ( Expression * expr = returnStmt->get_expr() ) {
                                if ( expr->get_env() ) {
                                        env = expr->get_env();
                                }
                        }

                        if ( retval && returnStmt->get_expr() ) {
                                assert( returnStmt->get_expr()->has_result() && ! returnStmt->get_expr()->get_result()->isVoid() );
                                delete returnStmt->get_expr();
                                returnStmt->set_expr( 0 );
                        } else {
                                returnStmt->set_expr( mutateExpression( returnStmt->get_expr() ) );
                        } // if
                        return returnStmt;
                }

                Type * Pass1::mutate( PointerType *pointerType ) {
                        scopeTyVars.beginScope();
                        makeTyVarMap( pointerType, scopeTyVars );

                        Type *ret = Mutator::mutate( pointerType );

                        scopeTyVars.endScope();
                        return ret;
                }

                Type * Pass1::mutate( FunctionType *functionType ) {
                        scopeTyVars.beginScope();
                        makeTyVarMap( functionType, scopeTyVars );

                        Type *ret = Mutator::mutate( functionType );

                        scopeTyVars.endScope();
                        return ret;
                }

                void Pass1::doBeginScope() {
                        adapters.beginScope();
                }

                void Pass1::doEndScope() {
                        adapters.endScope();
                }

////////////////////////////////////////// Pass2 ////////////////////////////////////////////////////

                void Pass2::addAdapters( FunctionType *functionType ) {
                        std::list< DeclarationWithType *> &paramList = functionType->get_parameters();
                        std::list< FunctionType *> functions;
                        for ( std::list< DeclarationWithType *>::iterator arg = paramList.begin(); arg != paramList.end(); ++arg ) {
                                Type *orig = (*arg)->get_type();
                                findAndReplaceFunction( orig, functions, scopeTyVars, needsAdapter );
                                (*arg)->set_type( orig );
                        }
                        std::set< std::string > adaptersDone;
                        for ( std::list< FunctionType *>::iterator funType = functions.begin(); funType != functions.end(); ++funType ) {
                                std::string mangleName = mangleAdapterName( *funType, scopeTyVars );
                                if ( adaptersDone.find( mangleName ) == adaptersDone.end() ) {
                                        std::string adapterName = makeAdapterName( mangleName );
                                        paramList.push_front( new ObjectDecl( adapterName, DeclarationNode::NoStorageClass, LinkageSpec::C, 0, new PointerType( Type::Qualifiers(), makeAdapterType( *funType, scopeTyVars ) ), 0 ) );
                                        adaptersDone.insert( adaptersDone.begin(), mangleName );
                                }
                        }
//  deleteAll( functions );
                }

                template< typename DeclClass >
                DeclClass * Pass2::handleDecl( DeclClass *decl, Type *type ) {
                        DeclClass *ret = static_cast< DeclClass *>( Mutator::mutate( decl ) );

                        return ret;
                }

                /// determines if `pref` is a prefix of `str`
                bool isPrefix( const std::string & str, const std::string & pref ) {
                        if ( pref.size() > str.size() ) return false;
                        auto its = std::mismatch( pref.begin(), pref.end(), str.begin() );
                        return its.first == pref.end();
                }

                DeclarationWithType * Pass2::mutate( FunctionDecl *functionDecl ) {
                        functionDecl = safe_dynamic_cast< FunctionDecl * > ( handleDecl( functionDecl, functionDecl->get_functionType() ) );
                        FunctionType * ftype = functionDecl->get_functionType();
                        if ( ! ftype->get_returnVals().empty() && functionDecl->get_statements() ) {
                                if ( functionDecl->get_name() != "?=?" && ! isPrefix( functionDecl->get_name(), "_thunk" ) ) { // xxx - remove check for ?=? once reference types are in; remove check for prefix once thunks properly use ctor/dtors
                                        assert( ftype->get_returnVals().size() == 1 );
                                        DeclarationWithType * retval = ftype->get_returnVals().front();
                                        if ( retval->get_name() == "" ) {
                                                retval->set_name( "_retval" );
                                        }
                                        functionDecl->get_statements()->get_kids().push_front( new DeclStmt( noLabels, retval ) );
                                        DeclarationWithType * newRet = retval->clone(); // for ownership purposes
                                        ftype->get_returnVals().front() = newRet;
                                }
                        }
                        return functionDecl;
                }

                ObjectDecl * Pass2::mutate( ObjectDecl *objectDecl ) {
                        return handleDecl( objectDecl, objectDecl->get_type() );
                }

                TypeDecl * Pass2::mutate( TypeDecl *typeDecl ) {
                        addToTyVarMap( typeDecl, scopeTyVars );
                        if ( typeDecl->get_base() ) {
                                return handleDecl( typeDecl, typeDecl->get_base() );
                        } else {
                                return Mutator::mutate( typeDecl );
                        }
                }

                TypedefDecl * Pass2::mutate( TypedefDecl *typedefDecl ) {
                        return handleDecl( typedefDecl, typedefDecl->get_base() );
                }

                Type * Pass2::mutate( PointerType *pointerType ) {
                        scopeTyVars.beginScope();
                        makeTyVarMap( pointerType, scopeTyVars );

                        Type *ret = Mutator::mutate( pointerType );

                        scopeTyVars.endScope();
                        return ret;
                }

                Type *Pass2::mutate( FunctionType *funcType ) {
                        scopeTyVars.beginScope();
                        makeTyVarMap( funcType, scopeTyVars );

                        // move polymorphic return type to parameter list
                        if ( isDynRet( funcType ) ) {
                                ObjectDecl *ret = safe_dynamic_cast< ObjectDecl* >( funcType->get_returnVals().front() );
                                ret->set_type( new PointerType( Type::Qualifiers(), ret->get_type() ) );
                                funcType->get_parameters().push_front( ret );
                                funcType->get_returnVals().pop_front();
                                ret->set_init( nullptr ); // xxx - memory leak?
                        }

                        // add size/align and assertions for type parameters to parameter list
                        std::list< DeclarationWithType *>::iterator last = funcType->get_parameters().begin();
                        std::list< DeclarationWithType *> inferredParams;
                        ObjectDecl newObj( "", DeclarationNode::NoStorageClass, LinkageSpec::C, 0, new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt ), 0 );
                        ObjectDecl newPtr( "", DeclarationNode::NoStorageClass, LinkageSpec::C, 0,
                                           new PointerType( Type::Qualifiers(), new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt ) ), 0 );
                        for ( Type::ForallList::const_iterator tyParm = funcType->get_forall().begin(); tyParm != funcType->get_forall().end(); ++tyParm ) {
                                ObjectDecl *sizeParm, *alignParm;
                                // add all size and alignment parameters to parameter list
                                if ( (*tyParm)->isComplete() ) {
                                        TypeInstType parmType( Type::Qualifiers(), (*tyParm)->get_name(), *tyParm );
                                        std::string parmName = mangleType( &parmType );

                                        sizeParm = newObj.clone();
                                        sizeParm->set_name( sizeofName( parmName ) );
                                        last = funcType->get_parameters().insert( last, sizeParm );
                                        ++last;

                                        alignParm = newObj.clone();
                                        alignParm->set_name( alignofName( parmName ) );
                                        last = funcType->get_parameters().insert( last, alignParm );
                                        ++last;
                                }
                                // move all assertions into parameter list
                                for ( std::list< DeclarationWithType *>::iterator assert = (*tyParm)->get_assertions().begin(); assert != (*tyParm)->get_assertions().end(); ++assert ) {
//      *assert = (*assert)->acceptMutator( *this );
                                        inferredParams.push_back( *assert );
                                }
                                (*tyParm)->get_assertions().clear();
                        }

                        // add size/align for generic parameter types to parameter list
                        std::set< std::string > seenTypes; // sizeofName for generic types we've seen
                        for ( std::list< DeclarationWithType* >::const_iterator fnParm = last; fnParm != funcType->get_parameters().end(); ++fnParm ) {
                                Type *polyType = isPolyType( (*fnParm)->get_type(), scopeTyVars );
                                if ( polyType && ! dynamic_cast< TypeInstType* >( polyType ) ) {
                                        std::string typeName = mangleType( polyType );
                                        if ( seenTypes.count( typeName ) ) continue;

                                        ObjectDecl *sizeParm, *alignParm, *offsetParm;
                                        sizeParm = newObj.clone();
                                        sizeParm->set_name( sizeofName( typeName ) );
                                        last = funcType->get_parameters().insert( last, sizeParm );
                                        ++last;

                                        alignParm = newObj.clone();
                                        alignParm->set_name( alignofName( typeName ) );
                                        last = funcType->get_parameters().insert( last, alignParm );
                                        ++last;

                                        if ( StructInstType *polyBaseStruct = dynamic_cast< StructInstType* >( polyType ) ) {
                                                // NOTE zero-length arrays are illegal in C, so empty structs have no offset array
                                                if ( ! polyBaseStruct->get_baseStruct()->get_members().empty() ) {
                                                        offsetParm = newPtr.clone();
                                                        offsetParm->set_name( offsetofName( typeName ) );
                                                        last = funcType->get_parameters().insert( last, offsetParm );
                                                        ++last;
                                                }
                                        }

                                        seenTypes.insert( typeName );
                                }
                        }

                        // splice assertion parameters into parameter list
                        funcType->get_parameters().splice( last, inferredParams );
                        addAdapters( funcType );
                        mutateAll( funcType->get_returnVals(), *this );
                        mutateAll( funcType->get_parameters(), *this );

                        scopeTyVars.endScope();
                        return funcType;
                }

////////////////////////////////////////// PolyGenericCalculator ////////////////////////////////////////////////////

                void PolyGenericCalculator::beginTypeScope( Type *ty ) {
                        scopeTyVars.beginScope();
                        makeTyVarMap( ty, scopeTyVars );
                }

                void PolyGenericCalculator::endTypeScope() {
                        scopeTyVars.endScope();
                }

                template< typename DeclClass >
                DeclClass * PolyGenericCalculator::handleDecl( DeclClass *decl, Type *type ) {
                        beginTypeScope( type );
                        // knownLayouts.beginScope();
                        // knownOffsets.beginScope();

                        DeclClass *ret = static_cast< DeclClass *>( Parent::mutate( decl ) );

                        // knownOffsets.endScope();
                        // knownLayouts.endScope();
                        endTypeScope();
                        return ret;
                }

                ObjectDecl * PolyGenericCalculator::mutate( ObjectDecl *objectDecl ) {
                        return handleDecl( objectDecl, objectDecl->get_type() );
                }

                DeclarationWithType * PolyGenericCalculator::mutate( FunctionDecl *functionDecl ) {
                        knownLayouts.beginScope();
                        knownOffsets.beginScope();

                        DeclarationWithType * decl = handleDecl( functionDecl, functionDecl->get_functionType() );
                        knownOffsets.endScope();
                        knownLayouts.endScope();
                        return decl;
                }

                TypedefDecl * PolyGenericCalculator::mutate( TypedefDecl *typedefDecl ) {
                        return handleDecl( typedefDecl, typedefDecl->get_base() );
                }

                TypeDecl * PolyGenericCalculator::mutate( TypeDecl *typeDecl ) {
                        addToTyVarMap( typeDecl, scopeTyVars );
                        return Parent::mutate( typeDecl );
                }

                Type * PolyGenericCalculator::mutate( PointerType *pointerType ) {
                        beginTypeScope( pointerType );

                        Type *ret = Parent::mutate( pointerType );

                        endTypeScope();
                        return ret;
                }

                Type * PolyGenericCalculator::mutate( FunctionType *funcType ) {
                        beginTypeScope( funcType );

                        // make sure that any type information passed into the function is accounted for
                        for ( std::list< DeclarationWithType* >::const_iterator fnParm = funcType->get_parameters().begin(); fnParm != funcType->get_parameters().end(); ++fnParm ) {
                                // condition here duplicates that in Pass2::mutate( FunctionType* )
                                Type *polyType = isPolyType( (*fnParm)->get_type(), scopeTyVars );
                                if ( polyType && ! dynamic_cast< TypeInstType* >( polyType ) ) {
                                        knownLayouts.insert( mangleType( polyType ) );
                                }
                        }

                        Type *ret = Parent::mutate( funcType );

                        endTypeScope();
                        return ret;
                }

                Statement *PolyGenericCalculator::mutate( DeclStmt *declStmt ) {
                        if ( ObjectDecl *objectDecl = dynamic_cast< ObjectDecl *>( declStmt->get_decl() ) ) {
                                if ( findGeneric( objectDecl->get_type() ) ) {
                                        // change initialization of a polymorphic value object
                                        // to allocate storage with alloca
                                        Type *declType = objectDecl->get_type();
                                        UntypedExpr *alloc = new UntypedExpr( new NameExpr( "__builtin_alloca" ) );
                                        alloc->get_args().push_back( new NameExpr( sizeofName( mangleType( declType ) ) ) );

                                        delete objectDecl->get_init();

                                        std::list<Expression*> designators;
                                        objectDecl->set_init( new SingleInit( alloc, designators, false ) ); // not constructed
                                }
                        }
                        return Parent::mutate( declStmt );
                }

                /// Finds the member in the base list that matches the given declaration; returns its index, or -1 if not present
                long findMember( DeclarationWithType *memberDecl, std::list< Declaration* > &baseDecls ) {
                        long i = 0;
                        for(std::list< Declaration* >::const_iterator decl = baseDecls.begin(); decl != baseDecls.end(); ++decl, ++i ) {
                                if ( memberDecl->get_name() != (*decl)->get_name() ) continue;

                                if ( DeclarationWithType *declWithType = dynamic_cast< DeclarationWithType* >( *decl ) ) {
                                        if ( memberDecl->get_mangleName().empty() || declWithType->get_mangleName().empty()
                                             || memberDecl->get_mangleName() == declWithType->get_mangleName() ) return i;
                                        else continue;
                                } else return i;
                        }
                        return -1;
                }

                /// Returns an index expression into the offset array for a type
                Expression *makeOffsetIndex( Type *objectType, long i ) {
                        std::stringstream offset_namer;
                        offset_namer << i;
                        ConstantExpr *fieldIndex = new ConstantExpr( Constant( new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt ), offset_namer.str() ) );
                        UntypedExpr *fieldOffset = new UntypedExpr( new NameExpr( "?[?]" ) );
                        fieldOffset->get_args().push_back( new NameExpr( offsetofName( mangleType( objectType ) ) ) );
                        fieldOffset->get_args().push_back( fieldIndex );
                        return fieldOffset;
                }

                /// Returns an expression dereferenced n times
                Expression *makeDerefdVar( Expression *derefdVar, long n ) {
                        for ( int i = 1; i < n; ++i ) {
                                UntypedExpr *derefExpr = new UntypedExpr( new NameExpr( "*?" ) );
                                derefExpr->get_args().push_back( derefdVar );
                                // xxx - should set results on derefExpr
                                derefdVar = derefExpr;
                        }
                        return derefdVar;
                }

                Expression *PolyGenericCalculator::mutate( MemberExpr *memberExpr ) {
                        // mutate, exiting early if no longer MemberExpr
                        Expression *expr = Parent::mutate( memberExpr );
                        memberExpr = dynamic_cast< MemberExpr* >( expr );
                        if ( ! memberExpr ) return expr;

                        // get declaration for base struct, exiting early if not found
                        int varDepth;
                        VariableExpr *varExpr = getBaseVar( memberExpr->get_aggregate(), &varDepth );
                        if ( ! varExpr ) return memberExpr;
                        ObjectDecl *objectDecl = dynamic_cast< ObjectDecl* >( varExpr->get_var() );
                        if ( ! objectDecl ) return memberExpr;

                        // only mutate member expressions for polymorphic types
                        int tyDepth;
                        Type *objectType = hasPolyBase( objectDecl->get_type(), scopeTyVars, &tyDepth );
                        if ( ! objectType ) return memberExpr;
                        findGeneric( objectType ); // ensure layout for this type is available

                        // replace member expression with dynamically-computed layout expression
                        Expression *newMemberExpr = 0;
                        if ( StructInstType *structType = dynamic_cast< StructInstType* >( objectType ) ) {
                                // look up offset index
                                long i = findMember( memberExpr->get_member(), structType->get_baseStruct()->get_members() );
                                if ( i == -1 ) return memberExpr;

                                // replace member expression with pointer to base plus offset
                                UntypedExpr *fieldLoc = new UntypedExpr( new NameExpr( "?+?" ) );
                                Expression * aggr = memberExpr->get_aggregate()->clone();
                                delete aggr->get_env(); // xxx - there's a problem with keeping the env for some reason, so for now just get rid of it
                                aggr->set_env( nullptr );
                                fieldLoc->get_args().push_back( aggr );
                                fieldLoc->get_args().push_back( makeOffsetIndex( objectType, i ) );
                                newMemberExpr = fieldLoc;
                        } else if ( dynamic_cast< UnionInstType* >( objectType ) ) {
                                // union members are all at offset zero, so build appropriately-dereferenced variable
                                newMemberExpr = makeDerefdVar( varExpr->clone(), varDepth );
                        } else return memberExpr;
                        assert( newMemberExpr );

                        Type *memberType = memberExpr->get_member()->get_type();
                        if ( ! isPolyType( memberType, scopeTyVars ) ) {
                                // Not all members of a polymorphic type are themselves of polymorphic type; in this case the member expression should be wrapped and dereferenced to form an lvalue
                                CastExpr *ptrCastExpr = new CastExpr( newMemberExpr, new PointerType( Type::Qualifiers(), memberType->clone() ) );
                                UntypedExpr *derefExpr = new UntypedExpr( new NameExpr( "*?" ) );
                                derefExpr->get_args().push_back( ptrCastExpr );
                                newMemberExpr = derefExpr;
                        }

                        delete memberExpr;
                        return newMemberExpr;
                }

                ObjectDecl *PolyGenericCalculator::makeVar( const std::string &name, Type *type, Initializer *init ) {
                        ObjectDecl *newObj = new ObjectDecl( name, DeclarationNode::NoStorageClass, LinkageSpec::C, 0, type, init );
                        stmtsToAdd.push_back( new DeclStmt( noLabels, newObj ) );
                        return newObj;
                }

                void PolyGenericCalculator::addOtypeParamsToLayoutCall( UntypedExpr *layoutCall, const std::list< Type* > &otypeParams ) {
                        for ( std::list< Type* >::const_iterator param = otypeParams.begin(); param != otypeParams.end(); ++param ) {
                                if ( findGeneric( *param ) ) {
                                        // push size/align vars for a generic parameter back
                                        std::string paramName = mangleType( *param );
                                        layoutCall->get_args().push_back( new NameExpr( sizeofName( paramName ) ) );
                                        layoutCall->get_args().push_back( new NameExpr( alignofName( paramName ) ) );
                                } else {
                                        layoutCall->get_args().push_back( new SizeofExpr( (*param)->clone() ) );
                                        layoutCall->get_args().push_back( new AlignofExpr( (*param)->clone() ) );
                                }
                        }
                }

                /// returns true if any of the otype parameters have a dynamic layout and puts all otype parameters in the output list
                bool findGenericParams( std::list< TypeDecl* > &baseParams, std::list< Expression* > &typeParams, std::list< Type* > &out ) {
                        bool hasDynamicLayout = false;

                        std::list< TypeDecl* >::const_iterator baseParam = baseParams.begin();
                        std::list< Expression* >::const_iterator typeParam = typeParams.begin();
                        for ( ; baseParam != baseParams.end() && typeParam != typeParams.end(); ++baseParam, ++typeParam ) {
                                // skip non-otype parameters
                                if ( ! (*baseParam)->isComplete() ) continue;
                                TypeExpr *typeExpr = dynamic_cast< TypeExpr* >( *typeParam );
                                assert( typeExpr && "all otype parameters should be type expressions" );

                                Type *type = typeExpr->get_type();
                                out.push_back( type );
                                if ( isPolyType( type ) ) hasDynamicLayout = true;
                        }
                        assert( baseParam == baseParams.end() && typeParam == typeParams.end() );

                        return hasDynamicLayout;
                }

                bool PolyGenericCalculator::findGeneric( Type *ty ) {
                        ty = replaceTypeInst( ty, env );

                        if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( ty ) ) {
                                if ( scopeTyVars.find( typeInst->get_name() ) != scopeTyVars.end() ) {
                                        // NOTE assumes here that getting put in the scopeTyVars included having the layout variables set
                                        return true;
                                }
                                return false;
                        } else if ( StructInstType *structTy = dynamic_cast< StructInstType* >( ty ) ) {
                                // check if this type already has a layout generated for it
                                std::string typeName = mangleType( ty );
                                if ( knownLayouts.find( typeName ) != knownLayouts.end() ) return true;

                                // check if any of the type parameters have dynamic layout; if none do, this type is (or will be) monomorphized
                                std::list< Type* > otypeParams;
                                if ( ! findGenericParams( *structTy->get_baseParameters(), structTy->get_parameters(), otypeParams ) ) return false;

                                // insert local variables for layout and generate call to layout function
                                knownLayouts.insert( typeName );  // done early so as not to interfere with the later addition of parameters to the layout call
                                Type *layoutType = new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt );

                                int n_members = structTy->get_baseStruct()->get_members().size();
                                if ( n_members == 0 ) {
                                        // all empty structs have the same layout - size 1, align 1
                                        makeVar( sizeofName( typeName ), layoutType, new SingleInit( new ConstantExpr( Constant::from_ulong( (unsigned long)1 ) ) ) );
                                        makeVar( alignofName( typeName ), layoutType->clone(), new SingleInit( new ConstantExpr( Constant::from_ulong( (unsigned long)1 ) ) ) );
                                        // NOTE zero-length arrays are forbidden in C, so empty structs have no offsetof array
                                } else {
                                        ObjectDecl *sizeVar = makeVar( sizeofName( typeName ), layoutType );
                                        ObjectDecl *alignVar = makeVar( alignofName( typeName ), layoutType->clone() );
                                        ObjectDecl *offsetVar = makeVar( offsetofName( typeName ), new ArrayType( Type::Qualifiers(), layoutType->clone(), new ConstantExpr( Constant::from_int( n_members ) ), false, false ) );

                                        // generate call to layout function
                                        UntypedExpr *layoutCall = new UntypedExpr( new NameExpr( layoutofName( structTy->get_baseStruct() ) ) );
                                        layoutCall->get_args().push_back( new AddressExpr( new VariableExpr( sizeVar ) ) );
                                        layoutCall->get_args().push_back( new AddressExpr( new VariableExpr( alignVar ) ) );
                                        layoutCall->get_args().push_back( new VariableExpr( offsetVar ) );
                                        addOtypeParamsToLayoutCall( layoutCall, otypeParams );

                                        stmtsToAdd.push_back( new ExprStmt( noLabels, layoutCall ) );
                                }

                                return true;
                        } else if ( UnionInstType *unionTy = dynamic_cast< UnionInstType* >( ty ) ) {
                                // check if this type already has a layout generated for it
                                std::string typeName = mangleType( ty );
                                if ( knownLayouts.find( typeName ) != knownLayouts.end() ) return true;

                                // check if any of the type parameters have dynamic layout; if none do, this type is (or will be) monomorphized
                                std::list< Type* > otypeParams;
                                if ( ! findGenericParams( *unionTy->get_baseParameters(), unionTy->get_parameters(), otypeParams ) ) return false;

                                // insert local variables for layout and generate call to layout function
                                knownLayouts.insert( typeName );  // done early so as not to interfere with the later addition of parameters to the layout call
                                Type *layoutType = new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt );

                                ObjectDecl *sizeVar = makeVar( sizeofName( typeName ), layoutType );
                                ObjectDecl *alignVar = makeVar( alignofName( typeName ), layoutType->clone() );

                                // generate call to layout function
                                UntypedExpr *layoutCall = new UntypedExpr( new NameExpr( layoutofName( unionTy->get_baseUnion() ) ) );
                                layoutCall->get_args().push_back( new AddressExpr( new VariableExpr( sizeVar ) ) );
                                layoutCall->get_args().push_back( new AddressExpr( new VariableExpr( alignVar ) ) );
                                addOtypeParamsToLayoutCall( layoutCall, otypeParams );

                                stmtsToAdd.push_back( new ExprStmt( noLabels, layoutCall ) );

                                return true;
                        }

                        return false;
                }

                Expression *PolyGenericCalculator::mutate( SizeofExpr *sizeofExpr ) {
                        Type *ty = sizeofExpr->get_type();
                        if ( findGeneric( ty ) ) {
                                Expression *ret = new NameExpr( sizeofName( mangleType( ty ) ) );
                                delete sizeofExpr;
                                return ret;
                        }
                        return sizeofExpr;
                }

                Expression *PolyGenericCalculator::mutate( AlignofExpr *alignofExpr ) {
                        Type *ty = alignofExpr->get_type();
                        if ( findGeneric( ty ) ) {
                                Expression *ret = new NameExpr( alignofName( mangleType( ty ) ) );
                                delete alignofExpr;
                                return ret;
                        }
                        return alignofExpr;
                }

                Expression *PolyGenericCalculator::mutate( OffsetofExpr *offsetofExpr ) {
                        // mutate, exiting early if no longer OffsetofExpr
                        Expression *expr = Parent::mutate( offsetofExpr );
                        offsetofExpr = dynamic_cast< OffsetofExpr* >( expr );
                        if ( ! offsetofExpr ) return expr;

                        // only mutate expressions for polymorphic structs/unions
                        Type *ty = offsetofExpr->get_type();
                        if ( ! findGeneric( ty ) ) return offsetofExpr;

                        if ( StructInstType *structType = dynamic_cast< StructInstType* >( ty ) ) {
                                // replace offsetof expression by index into offset array
                                long i = findMember( offsetofExpr->get_member(), structType->get_baseStruct()->get_members() );
                                if ( i == -1 ) return offsetofExpr;

                                Expression *offsetInd = makeOffsetIndex( ty, i );
                                delete offsetofExpr;
                                return offsetInd;
                        } else if ( dynamic_cast< UnionInstType* >( ty ) ) {
                                // all union members are at offset zero
                                delete offsetofExpr;
                                return new ConstantExpr( Constant( new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt ), "0" ) );
                        } else return offsetofExpr;
                }

                Expression *PolyGenericCalculator::mutate( OffsetPackExpr *offsetPackExpr ) {
                        StructInstType *ty = offsetPackExpr->get_type();

                        Expression *ret = 0;
                        if ( findGeneric( ty ) ) {
                                // pull offset back from generated type information
                                ret = new NameExpr( offsetofName( mangleType( ty ) ) );
                        } else {
                                std::string offsetName = offsetofName( mangleType( ty ) );
                                if ( knownOffsets.find( offsetName ) != knownOffsets.end() ) {
                                        // use the already-generated offsets for this type
                                        ret = new NameExpr( offsetName );
                                } else {
                                        knownOffsets.insert( offsetName );

                                        std::list< Declaration* > &baseMembers = ty->get_baseStruct()->get_members();
                                        Type *offsetType = new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt );

                                        // build initializer list for offset array
                                        std::list< Initializer* > inits;
                                        for ( std::list< Declaration* >::const_iterator member = baseMembers.begin(); member != baseMembers.end(); ++member ) {
                                                DeclarationWithType *memberDecl;
                                                if ( DeclarationWithType *origMember = dynamic_cast< DeclarationWithType* >( *member ) ) {
                                                        memberDecl = origMember->clone();
                                                } else {
                                                        memberDecl = new ObjectDecl( (*member)->get_name(), DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, offsetType->clone(), 0 );
                                                }
                                                inits.push_back( new SingleInit( new OffsetofExpr( ty->clone(), memberDecl ) ) );
                                        }

                                        // build the offset array and replace the pack with a reference to it
                                        ObjectDecl *offsetArray = makeVar( offsetName, new ArrayType( Type::Qualifiers(), offsetType, new ConstantExpr( Constant::from_ulong( baseMembers.size() ) ), false, false ),
                                                        new ListInit( inits ) );
                                        ret = new VariableExpr( offsetArray );
                                }
                        }

                        delete offsetPackExpr;
                        return ret;
                }

                void PolyGenericCalculator::doBeginScope() {
                        knownLayouts.beginScope();
                        knownOffsets.beginScope();
                }

                void PolyGenericCalculator::doEndScope() {
                        knownLayouts.endScope();
                        knownOffsets.endScope();
                }

////////////////////////////////////////// Pass3 ////////////////////////////////////////////////////

                template< typename DeclClass >
                DeclClass * Pass3::handleDecl( DeclClass *decl, Type *type ) {
                        scopeTyVars.beginScope();
                        makeTyVarMap( type, scopeTyVars );

                        DeclClass *ret = static_cast< DeclClass *>( Mutator::mutate( decl ) );
                        ScrubTyVars::scrub( decl, scopeTyVars );

                        scopeTyVars.endScope();
                        return ret;
                }

                ObjectDecl * Pass3::mutate( ObjectDecl *objectDecl ) {
                        return handleDecl( objectDecl, objectDecl->get_type() );
                }

                DeclarationWithType * Pass3::mutate( FunctionDecl *functionDecl ) {
                        return handleDecl( functionDecl, functionDecl->get_functionType() );
                }

                TypedefDecl * Pass3::mutate( TypedefDecl *typedefDecl ) {
                        return handleDecl( typedefDecl, typedefDecl->get_base() );
                }

                TypeDecl * Pass3::mutate( TypeDecl *typeDecl ) {
//   Initializer *init = 0;
//   std::list< Expression *> designators;
//   addToTyVarMap( typeDecl, scopeTyVars );
//   if ( typeDecl->get_base() ) {
//     init = new SimpleInit( new SizeofExpr( handleDecl( typeDecl, typeDecl->get_base() ) ), designators );
//   }
//   return new ObjectDecl( typeDecl->get_name(), Declaration::Extern, LinkageSpec::C, 0, new BasicType( Type::Qualifiers(), BasicType::UnsignedInt ), init );

                        addToTyVarMap( typeDecl, scopeTyVars );
                        return Mutator::mutate( typeDecl );
                }

                Type * Pass3::mutate( PointerType *pointerType ) {
                        scopeTyVars.beginScope();
                        makeTyVarMap( pointerType, scopeTyVars );

                        Type *ret = Mutator::mutate( pointerType );

                        scopeTyVars.endScope();
                        return ret;
                }

                Type * Pass3::mutate( FunctionType *functionType ) {
                        scopeTyVars.beginScope();
                        makeTyVarMap( functionType, scopeTyVars );

                        Type *ret = Mutator::mutate( functionType );

                        scopeTyVars.endScope();
                        return ret;
                }
        } // anonymous namespace
} // namespace GenPoly

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