Changes in src/GenPoly/Box.cc [1cced28:05d47278]

File:

• src/GenPoly/Box.cc (modified) (27 diffs)

src/GenPoly/Box.cc

@@ -22 +22 @@
 
 #include "Box.h"
+#include "InstantiateGeneric.h"
 #include "PolyMutator.h"
 #include "FindFunction.h"
+#include "ScopedMap.h"
 #include "ScrubTyVars.h"
 
@@ -69 +71 @@
                         virtual void doEndScope();
                   private:
+                        /// Makes a new temporary array holding the offsets of the fields of `type`, and returns a new variable expression referencing it
+                        Expression *makeOffsetArray( StructInstType *type );
+                        /// passes extra type parameters into a polymorphic function application
                         void passTypeVars( ApplicationExpr *appExpr, 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 );
-                        Expression *addPolyRetParam( ApplicationExpr *appExpr, FunctionType *function, std::string typeName, 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 *addPolyRetParam( ApplicationExpr *appExpr, FunctionType *function, ReferenceToType *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 findAssignOps( const std::list< TypeDecl *> &forall );
                         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 );
 
                         typedef std::map< std::string, DeclarationWithType *> AdapterMap;
                         std::map< std::string, DeclarationWithType *> assignOps;
+                        ScopedMap< std::string, DeclarationWithType *> scopedAssignOps;
                         std::stack< AdapterMap > adapters;
                         DeclarationWithType *retval;
@@ -107 +123 @@
                 };
 
-                /// 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 : public PolyMutator {
+                /// Replaces member expressions for polymorphic types with calculated add-field-offset-and-dereference
+                class MemberExprFixer : public PolyMutator {
                   public:
                         template< typename DeclClass >
@@ -119 +135 @@
                         virtual Type *mutate( PointerType *pointerType );
                         virtual Type *mutate( FunctionType *funcType );
+                        virtual Expression *mutate( MemberExpr *memberExpr );
+                };
+                
+                /// 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 : public PolyMutator {
+                  public:
+                        template< typename DeclClass >
+                        DeclClass *handleDecl( DeclClass *decl, Type *type );
+                        virtual DeclarationWithType *mutate( FunctionDecl *functionDecl );
+                        virtual ObjectDecl *mutate( ObjectDecl *objectDecl );
+                        virtual TypedefDecl *mutate( TypedefDecl *objectDecl );
+                        virtual TypeDecl *mutate( TypeDecl *objectDecl );
+                        virtual Type *mutate( PointerType *pointerType );
+                        virtual Type *mutate( FunctionType *funcType );
                   private:
                 };
@@ -133 +163 @@
         }
 
+        /// 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 ) {
                 Pass1 pass1;
                 Pass2 pass2;
+                MemberExprFixer memberFixer;
                 Pass3 pass3;
-                mutateAll( translationUnit, pass1 );
-                mutateAll( translationUnit, pass2 );
-                mutateAll( translationUnit, pass3 );
+                mutateTranslationUnit/*All*/( translationUnit, pass1 );
+                mutateTranslationUnit/*All*/( translationUnit, pass2 );
+                instantiateGeneric( translationUnit );
+                mutateTranslationUnit/*All*/( translationUnit, memberFixer );
+                mutateTranslationUnit/*All*/( translationUnit, pass3 );
         }
 
@@ -185 +244 @@
                 }
 
-                // returns true if the given declaration is: (*?=?)(T *, T) for some T (return not checked, but maybe should be)
-                bool checkAssignment( DeclarationWithType *decl, std::string &name ) {
+                /// returns T if the given declaration is: (*?=?)(T *, T) for some T (return not checked, but maybe should be), NULL otherwise
+                ReferenceToType *isAssignment( DeclarationWithType *decl ) {
                         if ( decl->get_name() == "?=?" ) {
-                                if ( PointerType *ptrType = dynamic_cast< PointerType *>( decl->get_type() ) ) {
-                                        if ( FunctionType *funType = dynamic_cast< FunctionType *>( ptrType->get_base() ) ) {
-                                                if ( funType->get_parameters().size() == 2 ) {
-                                                        if ( PointerType *pointer = dynamic_cast< PointerType *>( funType->get_parameters().front()->get_type() ) ) {
-                                                                if ( TypeInstType *typeInst = dynamic_cast< TypeInstType *>( pointer->get_base() ) ) {
-                                                                        if ( TypeInstType *typeInst2 = dynamic_cast< TypeInstType *>( funType->get_parameters().back()->get_type() ) ) {
-                                                                                if ( typeInst->get_name() == typeInst2->get_name() ) {
-                                                                                        name = typeInst->get_name();
-                                                                                        return true;
-                                                                                } // if
+                                if ( FunctionType *funType = getFunctionType( decl->get_type() ) ) {
+                                        if ( funType->get_parameters().size() == 2 ) {
+                                                if ( PointerType *pointer = dynamic_cast< PointerType *>( funType->get_parameters().front()->get_type() ) ) {
+                                                        if ( ReferenceToType *refType = dynamic_cast< ReferenceToType *>( pointer->get_base() ) ) {
+                                                                if ( ReferenceToType *refType2 = dynamic_cast< ReferenceToType *>( funType->get_parameters().back()->get_type() ) ) {
+                                                                        if ( refType->get_name() == refType2->get_name() ) {
+                                                                                return refType;
                                                                         } // if
                                                                 } // if
@@ -205 +261 @@
                                 } // if
                         } // if
-                        return false;
+                        return 0;
                 }
 
@@ -214 +270 @@
                                 for ( std::list< DeclarationWithType *>::const_iterator assert = (*i)->get_assertions().begin(); assert != (*i)->get_assertions().end(); ++assert ) {
                                         std::string typeName;
-                                        if ( checkAssignment( *assert, typeName ) ) {
-                                                assignOps[ typeName ] = *assert;
+                                        if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( isAssignment( *assert ) ) ) {
+                                                assignOps[ typeInst->get_name() ] = *assert;
                                         } // if
                                 } // for
@@ -222 +278 @@
 
                 DeclarationWithType *Pass1::mutate( FunctionDecl *functionDecl ) {
+                        // if this is a polymorphic assignment function, put it in the map for this scope
+                        if ( ReferenceToType *refType = isAssignment( functionDecl ) ) {
+                                if ( ! dynamic_cast< TypeInstType* >( refType ) ) {
+                                        scopedAssignOps.insert( refType->get_name(), functionDecl );
+                                }
+                        }
+                        
                         if ( functionDecl->get_statements() ) {         // empty routine body ?
                                 doBeginScope();
@@ -231 +294 @@
                                 // process polymorphic return value
                                 retval = 0;
-                                std::string typeName;
-                                if ( isPolyRet( functionDecl->get_functionType(), typeName ) && functionDecl->get_linkage() == LinkageSpec::Cforall ) {
+                                if ( isPolyRet( functionDecl->get_functionType() ) && functionDecl->get_linkage() == LinkageSpec::Cforall ) {
                                         retval = functionDecl->get_functionType()->get_returnVals().front();
 
@@ -256 +318 @@
                                         findFunction( (*arg)->get_type(), functions, scopeTyVars, needsAdapter );
                                 } // for
+                                
                                 AdapterMap & adapters = Pass1::adapters.top();
                                 for ( std::list< FunctionType *>::iterator funType = functions.begin(); funType != functions.end(); ++funType ) {
@@ -306 +369 @@
                 }
 
+                Expression *Pass1::makeOffsetArray( StructInstType *ty ) {
+                        // make a new temporary array
+                        Type *offsetType = new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt );
+                        ObjectDecl *arrayTemp = makeTemporary( new PointerType( Type::Qualifiers(), offsetType ) );
+
+                        // build initializer list for temporary
+                        std::list< Initializer* > inits;
+                        StructDecl *tyBase = ty->get_baseStruct();
+                        for ( std::list< Declaration* >::const_iterator member = tyBase->get_members().begin(); member != tyBase->get_members().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 ) ) );
+                        }
+                        arrayTemp->set_init( new ListInit( inits ) );
+
+                        // return variable pointing to temporary
+                        return new VariableExpr( arrayTemp );
+                }
+                
                 void Pass1::passTypeVars( ApplicationExpr *appExpr, std::list< Expression *>::iterator &arg, const TyVarMap &exprTyVars ) {
                         // pass size/align for type variables
@@ -325 +411 @@
 
                         // add size/align for generic types to parameter list
-                        //assert( ! appExpr->get_function()->get_results().empty() );
                         if ( appExpr->get_function()->get_results().empty() ) return;
                         FunctionType *funcType = getFunctionType( appExpr->get_function()->get_results().front() );
@@ -345 +430 @@
                                         arg = appExpr->get_args().insert( arg, new AlignofExpr( argType->clone() ) );
                                         arg++;
+                                        if ( dynamic_cast< StructInstType* >( parmType ) ) {
+                                                if ( StructInstType *argStructType = dynamic_cast< StructInstType* >( argType ) ) {
+                                                        arg = appExpr->get_args().insert( arg, makeOffsetArray( argStructType ) );
+                                                        arg++;
+                                                } else {
+                                                        throw SemanticError( "Cannot pass non-struct type for generic struct" );
+                                                }
+                                        }
 
                                         seenTypes.insert( sizeName );
@@ -386 +479 @@
                 }
 
-                Expression *Pass1::addPolyRetParam( ApplicationExpr *appExpr, FunctionType *function, std::string typeName, std::list< Expression *>::iterator &arg ) {
-                        ResolvExpr::EqvClass eqvClass;
+                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 ) {
+                                        throw SemanticError( "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::addPolyRetParam( ApplicationExpr *appExpr, FunctionType *function, ReferenceToType *polyType, std::list< Expression *>::iterator &arg ) {
                         assert( env );
-                        Type *concrete = env->lookup( typeName );
-                        if ( concrete == 0 ) {
-                                throw SemanticError( "Unbound type variable " + typeName + " in ", appExpr );
-                        } // if
+                        Type *concrete = replaceWithConcrete( appExpr, polyType );
                         return addRetParam( appExpr, function, concrete, arg );
                 }
@@ -492 +612 @@
                         assert( arg );
                         if ( isPolyType( realParam->get_type(), tyVars ) ) {
-//     if ( dynamic_cast< PointerType *>( arg->get_type() ) ) {
-//       return new CastExpr( new VariableExpr( param ), arg->get_type()->clone() );
-//     } else {
                                 if ( dynamic_cast<TypeInstType *>(arg->get_type()) == NULL ) {
                                         UntypedExpr *deref = new UntypedExpr( new NameExpr( "*?" ) );
@@ -501 +618 @@
                                         return deref;
                                 } // if
-//     }
                         } // if
                         return new VariableExpr( param );
@@ -791 +907 @@
                         std::list< Expression *>::iterator paramBegin = appExpr->get_args().begin();
 
-                        std::string typeName;
-                        if ( isPolyRet( function, typeName ) ) {
-                                ret = addPolyRetParam( appExpr, function, typeName, arg );
+                        if ( ReferenceToType *polyType = isPolyRet( function ) ) {
+                                ret = addPolyRetParam( appExpr, function, polyType, arg );
                         } else if ( needsAdapter( function, scopeTyVars ) ) {
                                 // std::cerr << "needs adapter: ";
@@ -880 +995 @@
                                         delete castExpr;
                                 } //while
-                                TypeInstType *typeInst = dynamic_cast< TypeInstType *>( retval->get_type() );
-                                assert( typeInst );
-                                std::map< std::string, DeclarationWithType *>::const_iterator assignIter = assignOps.find( typeInst->get_name() );
-                                if ( assignIter == assignOps.end() ) {
-                                        throw SemanticError( "Attempt to return dtype or ftype object in ", returnStmt->get_expr() );
-                                } // if
-                                ApplicationExpr *assignExpr = new ApplicationExpr( new VariableExpr( assignIter->second ) );
+
+                                // find assignment operator for (polymorphic) return type
+                                DeclarationWithType *assignDecl = 0;
+                                if ( TypeInstType *typeInst = dynamic_cast< TypeInstType *>( retval->get_type() ) ) {
+                                        std::map< std::string, DeclarationWithType *>::const_iterator assignIter = assignOps.find( typeInst->get_name() );
+                                        if ( assignIter == assignOps.end() ) {
+                                                throw SemanticError( "Attempt to return dtype or ftype object in ", returnStmt->get_expr() );
+                                        } // if
+                                        assignDecl = assignIter->second;
+                                } else if ( ReferenceToType *refType = dynamic_cast< ReferenceToType *>( retval->get_type() ) ) {
+                                        ScopedMap< std::string, DeclarationWithType *>::const_iterator assignIter = scopedAssignOps.find( refType->get_name() );
+                                        if ( assignIter == scopedAssignOps.end() ) {
+                                                throw SemanticError( "Attempt to return dtype or ftype generic object in ", returnStmt->get_expr() );
+                                        }
+                                        DeclarationWithType *functionDecl = assignIter->second;
+                                        // line below cloned from FixFunction.cc
+                                        assignDecl = new ObjectDecl( functionDecl->get_name(), functionDecl->get_storageClass(), functionDecl->get_linkage(), 0,
+                                                                     new PointerType( Type::Qualifiers(), functionDecl->get_type()->clone() ), 0 );
+                                        assignDecl->set_mangleName( functionDecl->get_mangleName() );
+                                }
+                                assert( assignDecl );
+
+                                // replace return statement with appropriate assignment to out parameter
+                                ApplicationExpr *assignExpr = new ApplicationExpr( new VariableExpr( assignDecl ) );
                                 Expression *retParm = new NameExpr( retval->get_name() );
                                 retParm->get_results().push_back( new PointerType( Type::Qualifiers(), retval->get_type()->clone() ) );
@@ -927 +1059 @@
                         // push a copy of the current map
                         adapters.push(adapters.top());
+                        scopedAssignOps.beginScope();
                 }
 
                 void Pass1::doEndScope() {
                         adapters.pop();
+                        scopedAssignOps.endScope();
                 }
 
@@ -998 +1132 @@
 
                         // move polymorphic return type to parameter list
-                        std::string typeName;
-                        if ( isPolyRet( funcType, typeName ) ) {
+                        if ( isPolyRet( funcType ) ) {
                                 DeclarationWithType *ret = funcType->get_returnVals().front();
                                 ret->set_type( new PointerType( Type::Qualifiers(), ret->get_type() ) );
@@ -1010 +1143 @@
                         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 );
 //   ObjectDecl *newFunPtr = new ObjectDecl( "", DeclarationNode::NoStorageClass, LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), new FunctionType( Type::Qualifiers(), true ) ), 0 );
                         for ( std::list< TypeDecl *>::const_iterator tyParm = funcType->get_forall().begin(); tyParm != funcType->get_forall().end(); ++tyParm ) {
@@ -1036 +1171 @@
 
                         // add size/align for generic types to parameter list
-                        std::set< std::string > seenTypes; //< sizeofName for generic types we've seen
+                        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 *parmType = (*fnParm)->get_type();
@@ -1043 +1178 @@
                                         if ( seenTypes.count( sizeName ) ) continue;
 
-                                        ObjectDecl *sizeParm, *alignParm;
+                                        ObjectDecl *sizeParm, *alignParm, *offsetParm;
                                         sizeParm = newObj.clone();
                                         sizeParm->set_name( sizeName );
@@ -1053 +1188 @@
                                         last = funcType->get_parameters().insert( last, alignParm );
                                         ++last;
+
+                                        if ( dynamic_cast< StructInstType* >( parmType ) ) {
+                                                offsetParm = newPtr.clone();
+                                                offsetParm->set_name( offsetofName( parmType ) );
+                                                last = funcType->get_parameters().insert( last, offsetParm );
+                                                ++last;
+                                        }
 
                                         seenTypes.insert( sizeName );
@@ -1066 +1208 @@
                         scopeTyVars = oldtyVars;
                         return funcType;
+                }
+
+////////////////////////////////////////// MemberExprFixer ////////////////////////////////////////////////////
+
+                template< typename DeclClass >
+                DeclClass * MemberExprFixer::handleDecl( DeclClass *decl, Type *type ) {
+                        TyVarMap oldtyVars = scopeTyVars;
+                        makeTyVarMap( type, scopeTyVars );
+
+                        DeclClass *ret = static_cast< DeclClass *>( Mutator::mutate( decl ) );
+
+                        scopeTyVars = oldtyVars;
+                        return ret;
+                }
+
+                ObjectDecl * MemberExprFixer::mutate( ObjectDecl *objectDecl ) {
+                        return handleDecl( objectDecl, objectDecl->get_type() );
+                }
+
+                DeclarationWithType * MemberExprFixer::mutate( FunctionDecl *functionDecl ) {
+                        return handleDecl( functionDecl, functionDecl->get_functionType() );
+                }
+
+                TypedefDecl * MemberExprFixer::mutate( TypedefDecl *typedefDecl ) {
+                        return handleDecl( typedefDecl, typedefDecl->get_base() );
+                }
+
+                TypeDecl * MemberExprFixer::mutate( TypeDecl *typeDecl ) {
+                        scopeTyVars[ typeDecl->get_name() ] = typeDecl->get_kind();
+                        return Mutator::mutate( typeDecl );
+                }
+
+                Type * MemberExprFixer::mutate( PointerType *pointerType ) {
+                        TyVarMap oldtyVars = scopeTyVars;
+                        makeTyVarMap( pointerType, scopeTyVars );
+
+                        Type *ret = Mutator::mutate( pointerType );
+
+                        scopeTyVars = oldtyVars;
+                        return ret;
+                }
+
+                Type * MemberExprFixer::mutate( FunctionType *functionType ) {
+                        TyVarMap oldtyVars = scopeTyVars;
+                        makeTyVarMap( functionType, scopeTyVars );
+
+                        Type *ret = Mutator::mutate( functionType );
+
+                        scopeTyVars = oldtyVars;
+                        return ret;
+                }
+
+                Statement *MemberExprFixer::mutate( DeclStmt *declStmt ) {
+                        if ( ObjectDecl *objectDecl = dynamic_cast< ObjectDecl *>( declStmt->get_decl() ) ) {
+                                if ( isPolyType( objectDecl->get_type(), scopeTyVars ) ) {
+                                        // 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( declType ) ) );
+
+                                        delete objectDecl->get_init();
+
+                                        std::list<Expression*> designators;
+                                        objectDecl->set_init( new SingleInit( alloc, designators ) );
+                                }
+                        }
+                        return Mutator::mutate( declStmt );
+                }
+
+                Expression *MemberExprFixer::mutate( MemberExpr *memberExpr ) {
+                        // mutate, exiting early if no longer MemberExpr
+                        Expression *expr = Mutator::mutate( memberExpr );
+                        memberExpr = dynamic_cast< MemberExpr* >( expr );
+                        if ( ! memberExpr ) return expr;
+
+                        // get declaration for base struct, exiting early if not found
+                        VariableExpr *varExpr = getBaseVar( memberExpr->get_aggregate() );
+                        if ( ! varExpr ) return memberExpr;
+                        ObjectDecl *objectDecl = dynamic_cast< ObjectDecl* >( varExpr->get_var() );
+                        if ( ! objectDecl ) return memberExpr;
+
+                        // only mutate member expressions for polymorphic types
+                        Type *objectType = hasPolyBase( objectDecl->get_type(), scopeTyVars );
+                        if ( ! objectType ) return memberExpr;
+
+                        // get base aggregate for type so members can be looked up
+                        AggregateDecl *memberBase = 0;
+                        if ( StructInstType *structType = dynamic_cast< StructInstType* >( objectType ) ) {
+                                memberBase = structType->get_baseStruct();
+                        } else if ( UnionInstType *unionType = dynamic_cast< UnionInstType* >( objectType ) ) {
+                                memberBase = unionType->get_baseUnion();
+                        } else return memberExpr;
+
+                        // look up numeric index of member in base aggregate
+                        DeclarationWithType *memberDecl = memberExpr->get_member();
+                        std::list< Declaration* > &baseDecls = memberBase->get_members();
+                        std::list< Declaration* >::const_iterator decl = baseDecls.begin();
+                        unsigned long i = 0;
+                        for( ; decl != baseDecls.end(); ++decl, ++i ) {
+                                if ( memberDecl->get_name() != (*decl)->get_name() ) continue;
+
+                                if ( DeclarationWithType *declWithType = dynamic_cast< DeclarationWithType* >( *decl ) ) {
+                                        if ( memberDecl->get_mangleName() == declWithType->get_mangleName() ) break;
+                                        else continue;
+                                } else break;
+                        }
+                        if ( decl == baseDecls.end() ) return memberExpr;
+
+                        // replace member expression with dereference of pointer offset
+                        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( objectType ) ) );
+                        fieldOffset->get_args().push_back( fieldIndex );
+                        UntypedExpr *fieldLoc = new UntypedExpr( new NameExpr( "?+?" ) );
+                        fieldLoc->get_args().push_back( memberExpr->get_aggregate() );
+                        fieldLoc->get_args().push_back( fieldOffset );
+                        UntypedExpr *ret = new UntypedExpr( new NameExpr( "*?" ) );
+                        ret->get_args().push_back( fieldLoc );
+
+                        memberExpr->set_aggregate( 0 );
+                        delete memberExpr;
+                        return ret;
                 }
 
@@ -1126 +1393 @@
                         return ret;
                 }
-
-                Statement *Pass3::mutate( DeclStmt *declStmt ) {
-                        if ( ObjectDecl *objectDecl = dynamic_cast< ObjectDecl *>( declStmt->get_decl() ) ) {
-                                if ( isPolyType( objectDecl->get_type(), scopeTyVars ) ) {
-                                        // 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( declType ) ) );
-
-                                        delete objectDecl->get_init();
-
-                                        std::list<Expression*> designators;
-                                        objectDecl->set_init( new SingleInit( alloc, designators ) );
-                                }
-                        }
-                        return Mutator::mutate( declStmt );
-                }
         } // anonymous namespace
 } // namespace GenPoly