source: src/SymTab/Indexer.cc @ fdfb0ba

//
// 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.
//
// Indexer.cc --
//
// Author           : Richard C. Bilson
// Created On       : Sun May 17 21:37:33 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Fri Dec 13 23:43:19 2019
// Update Count     : 22
//

#include "Indexer.h"

#include <cassert>                 // for assert, strict_dynamic_cast
#include <string>                  // for string, operator<<, operator!=
#include <memory>                  // for shared_ptr, make_shared
#include <unordered_map>           // for operator!=, unordered_map<>::const...
#include <unordered_set>           // for unordered_set
#include <utility>                 // for pair, make_pair, move
#include <vector>                  // for vector

#include "CodeGen/OperatorTable.h" // for isCtorDtor, isCtorDtorAssign
#include "Common/SemanticError.h"  // for SemanticError
#include "Common/utility.h"        // for cloneAll
#include "Common/Stats/Counter.h"  // for counters
#include "GenPoly/GenPoly.h"       // for getFunctionType
#include "InitTweak/InitTweak.h"   // for isConstructor, isCopyFunction, isC...
#include "Mangler.h"               // for Mangler
#include "ResolvExpr/typeops.h"    // for typesCompatible
#include "SynTree/LinkageSpec.h"   // for isMangled, isOverridable, Spec
#include "SynTree/Constant.h"      // for Constant
#include "SynTree/Declaration.h"   // for DeclarationWithType, FunctionDecl
#include "SynTree/Expression.h"    // for Expression, ImplicitCopyCtorExpr
#include "SynTree/Initializer.h"   // for Initializer
#include "SynTree/Statement.h"     // for CompoundStmt, Statement, ForStmt (...
#include "SynTree/Type.h"          // for Type, StructInstType, UnionInstType

namespace SymTab {

        // Statistics block
        namespace {
                static inline auto stats() {
                        using namespace Stats::Counters;
                        static auto group   = build<CounterGroup>("Indexers");
                        static struct {
                                SimpleCounter * count;
                                AverageCounter<double> * size;
                                SimpleCounter * new_scopes;
                                SimpleCounter * lazy_scopes;
                                AverageCounter<double> * avg_scope_depth;
                                MaxCounter<size_t> * max_scope_depth;
                                SimpleCounter * add_calls;
                                SimpleCounter * lookup_calls;
                                SimpleCounter * map_lookups;
                                SimpleCounter * map_mutations;
                        } ret = {
                                .count   = build<SimpleCounter>("Count", group),
                                .size    = build<AverageCounter<double>>("Average Size", group),
                                .new_scopes = build<SimpleCounter>("Scopes", group),
                                .lazy_scopes = build<SimpleCounter>("Lazy Scopes", group),
                                .avg_scope_depth = build<AverageCounter<double>>("Average Scope", group),
                                .max_scope_depth = build<MaxCounter<size_t>>("Max Scope", group),
                                .add_calls = build<SimpleCounter>("Add Calls", group),
                                .lookup_calls = build<SimpleCounter>("Lookup Calls", group),
                                .map_lookups = build<SimpleCounter>("Map Lookups", group),
                                .map_mutations = build<SimpleCounter>("Map Mutations", group)
                        };
                        return ret;
                }
        }

        Indexer::Indexer( bool trackIdentifiers )
        : idTable(), typeTable(), structTable(), enumTable(), unionTable(), traitTable(),
          prevScope(), scope( 0 ), repScope( 0 ), trackIdentifiers( trackIdentifiers ) { ++* stats().count; }

        Indexer::~Indexer() {
                stats().size->push( idTable ? idTable->size() : 0 );
        }

        void Indexer::lazyInitScope() {
                if ( repScope < scope ) {
                        ++* stats().lazy_scopes;
                        // create rollback
                        prevScope = std::make_shared<Indexer>( * this );
                        // update repScope
                        repScope = scope;
                }
        }

        void Indexer::enterScope() {
                ++scope;

                ++* stats().new_scopes;
                stats().avg_scope_depth->push( scope );
                stats().max_scope_depth->push( scope );
        }

        void Indexer::leaveScope() {
                if ( repScope == scope ) {
                        Ptr prev = prevScope;           // make sure prevScope stays live
                        * this = std::move(* prevScope);  // replace with previous scope
                }

                --scope;
        }

        void Indexer::lookupId( const std::string & id, std::list< IdData > &out ) const {
                assert( trackIdentifiers );

                ++* stats().lookup_calls;
                if ( ! idTable ) return;

                ++* stats().map_lookups;
                auto decls = idTable->find( id );
                if ( decls == idTable->end() ) return;

                for ( auto decl : *(decls->second) ) {
                        out.push_back( decl.second );
                }
        }

        const NamedTypeDecl * Indexer::lookupType( const std::string & id ) const {
                ++* stats().lookup_calls;
                if ( ! typeTable ) return nullptr;
                ++* stats().map_lookups;
                auto it = typeTable->find( id );
                return it == typeTable->end() ? nullptr : it->second.decl;
        }

        const StructDecl * Indexer::lookupStruct( const std::string & id ) const {
                ++* stats().lookup_calls;
                if ( ! structTable ) return nullptr;
                ++* stats().map_lookups;
                auto it = structTable->find( id );
                return it == structTable->end() ? nullptr : it->second.decl;
        }

        const EnumDecl * Indexer::lookupEnum( const std::string & id ) const {
                ++* stats().lookup_calls;
                if ( ! enumTable ) return nullptr;
                ++* stats().map_lookups;
                auto it = enumTable->find( id );
                return it == enumTable->end() ? nullptr : it->second.decl;
        }

        const UnionDecl * Indexer::lookupUnion( const std::string & id ) const {
                ++* stats().lookup_calls;
                if ( ! unionTable ) return nullptr;
                ++* stats().map_lookups;
                auto it = unionTable->find( id );
                return it == unionTable->end() ? nullptr : it->second.decl;
        }

        const TraitDecl * Indexer::lookupTrait( const std::string & id ) const {
                ++* stats().lookup_calls;
                if ( ! traitTable ) return nullptr;
                ++* stats().map_lookups;
                auto it = traitTable->find( id );
                return it == traitTable->end() ? nullptr : it->second.decl;
        }

        const Indexer * Indexer::atScope( unsigned long target ) const {
                // by lazy construction, final indexer in list has repScope 0, cannot be > target
                // otherwise, will find first scope representing the target
                const Indexer * indexer = this;
                while ( indexer->repScope > target ) {
                        indexer = indexer->prevScope.get();
                }
                return indexer;
        }

        const NamedTypeDecl * Indexer::globalLookupType( const std::string & id ) const {
                return atScope( 0 )->lookupType( id );
        }

        const StructDecl * Indexer::globalLookupStruct( const std::string & id ) const {
                return atScope( 0 )->lookupStruct( id );
        }

        const UnionDecl * Indexer::globalLookupUnion( const std::string & id ) const {
                return atScope( 0 )->lookupUnion( id );
        }

        const EnumDecl * Indexer::globalLookupEnum( const std::string & id ) const {
                return atScope( 0 )->lookupEnum( id );
        }

        bool isFunction( const DeclarationWithType * decl ) {
                return GenPoly::getFunctionType( decl->get_type() );
        }

        bool isObject( const DeclarationWithType * decl ) {
                return ! isFunction( decl );
        }

        bool isDefinition( const DeclarationWithType * decl ) {
                if ( const FunctionDecl * func = dynamic_cast< const FunctionDecl * >( decl ) ) {
                        // a function is a definition if it has a body
                        return func->statements;
                } else {
                        // an object is a definition if it is not marked extern.
                        // both objects must be marked extern
                        return ! decl->get_storageClasses().is_extern;
                }
        }


        bool Indexer::addedIdConflicts(
                        const Indexer::IdData & existing, const DeclarationWithType * added,
                        Indexer::OnConflict handleConflicts, const Declaration * deleteStmt ) {
                // if we're giving the same name mangling to things of different types then there is
                // something wrong
                assert( (isObject( added ) && isObject( existing.id ) )
                        || ( isFunction( added ) && isFunction( existing.id ) ) );

                if ( LinkageSpec::isOverridable( existing.id->linkage ) ) {
                        // new definition shadows the autogenerated one, even at the same scope
                        return false;
                } else if ( LinkageSpec::isMangled( added->linkage )
                                || ResolvExpr::typesCompatible(
                                        added->get_type(), existing.id->get_type(), Indexer() ) ) {

                        // it is a conflict if one declaration is deleted and the other is not
                        if ( deleteStmt && ! existing.deleteStmt ) {
                                if ( handleConflicts.mode == OnConflict::Error ) {
                                        SemanticError( added, "deletion of defined identifier " );
                                }
                                return true;
                        } else if ( ! deleteStmt && existing.deleteStmt ) {
                                if ( handleConflicts.mode == OnConflict::Error ) {
                                        SemanticError( added, "definition of deleted identifier " );
                                }
                                return true;
                        }

                        if ( isDefinition( added ) && isDefinition( existing.id ) ) {
                                if ( handleConflicts.mode == OnConflict::Error ) {
                                        SemanticError( added,
                                                isFunction( added ) ?
                                                        "duplicate function definition for " :
                                                        "duplicate object definition for " );
                                }
                                return true;
                        } // if
                } else {
                        if ( handleConflicts.mode == OnConflict::Error ) {
                                SemanticError( added, "duplicate definition for " );
                        }
                        return true;
                } // if

                return true;
        }

        bool Indexer::hasCompatibleCDecl( const std::string & id, const std::string &mangleName ) const {
                if ( ! idTable ) return false;

                ++* stats().map_lookups;
                auto decls = idTable->find( id );
                if ( decls == idTable->end() ) return false;

                for ( auto decl : *(decls->second) ) {
                        // skip other scopes (hidden by this decl)
                        if ( decl.second.scope != scope ) continue;
                        // check for C decl with compatible type (by mangleName)
                        if ( ! LinkageSpec::isMangled( decl.second.id->linkage ) && decl.first == mangleName ) {
                                return true;
                        }
                }

                return false;
        }

        bool Indexer::hasIncompatibleCDecl(const std::string & id, const std::string &mangleName ) const {
                if ( ! idTable ) return false;

                ++* stats().map_lookups;
                auto decls = idTable->find( id );
                if ( decls == idTable->end() ) return false;

                for ( auto decl : *(decls->second) ) {
                        // skip other scopes (hidden by this decl)
                        if ( decl.second.scope != scope ) continue;
                        // check for C decl with incompatible type (by manglename)
                        if ( ! LinkageSpec::isMangled( decl.second.id->linkage ) && decl.first != mangleName ) {
                                return true;
                        }
                }

                return false;
        }

        /// gets the base type of the first parameter; decl must be a ctor/dtor/assignment function
        std::string getOtypeKey( const FunctionDecl * function ) {
                auto& params = function->type->parameters;
                assert( ! params.empty() );
                // use base type of pointer, so that qualifiers on the pointer type aren't considered.
                Type * base = InitTweak::getPointerBase( params.front()->get_type() );
                assert( base );
                return Mangler::mangle( base );
        }

        /// gets the declaration for the function acting on a type specified by otype key,
        /// nullptr if none such
        const FunctionDecl * getFunctionForOtype( const DeclarationWithType * decl, const std::string& otypeKey ) {
                const FunctionDecl * func = dynamic_cast< const FunctionDecl * >( decl );
                if ( ! func || otypeKey != getOtypeKey( func ) ) return nullptr;
                return func;
        }

        bool Indexer::removeSpecialOverrides(Indexer::IdData& data, Indexer::MangleTable::Ptr& mangleTable ) {
                // if a type contains user defined ctor/dtor/assign, then special rules trigger, which
                // determinethe set of ctor/dtor/assign that can be used  by the requester. In particular,
                // if the user defines a default ctor, then the generated default ctor is unavailable,
                // likewise for copy ctor and dtor. If the user defines any ctor/dtor, then no generated
                // field ctors are available. If the user defines any ctor then the generated default ctor
                // is unavailable (intrinsic default ctor must be overridden exactly). If the user defines
                // anything that looks like a copy constructor, then the generated copy constructor is
                // unavailable, and likewise for the assignment operator.

                // only relevant on function declarations
                const FunctionDecl * function = dynamic_cast< const FunctionDecl * >( data.id );
                if ( ! function ) return true;
                // only need to perform this check for constructors, destructors, and assignment functions
                if ( ! CodeGen::isCtorDtorAssign( data.id->name ) ) return true;

                // set up information for this type
                bool dataIsUserDefinedFunc = ! LinkageSpec::isOverridable( function->linkage );
                bool dataIsCopyFunc = InitTweak::isCopyFunction( function, function->name );
                std::string dataOtypeKey = getOtypeKey( function );

                if ( dataIsUserDefinedFunc && dataIsCopyFunc ) {
                        // this is a user-defined copy function
                        // if this is the first such, delete/remove non-user-defined overloads as needed
                        std::vector< std::string > removed;
                        std::vector< MangleTable::value_type > deleted;
                        bool alreadyUserDefinedFunc = false;

                        for ( const auto& entry : * mangleTable ) {
                                // skip decls that aren't functions or are for the wrong type
                                const FunctionDecl * decl = getFunctionForOtype( entry.second.id, dataOtypeKey );
                                if ( ! decl ) continue;

                                bool isCopyFunc = InitTweak::isCopyFunction( decl, decl->name );
                                if ( ! LinkageSpec::isOverridable( decl->linkage ) ) {
                                        // matching user-defined function
                                        if ( isCopyFunc ) {
                                                // mutation already performed, return early
                                                return true;
                                        } else {
                                                // note that non-copy deletions already performed
                                                alreadyUserDefinedFunc = true;
                                        }
                                } else {
                                        // non-user-defined function; mark for deletion/removal as appropriate
                                        if ( isCopyFunc ) {
                                                removed.push_back( entry.first );
                                        } else if ( ! alreadyUserDefinedFunc ) {
                                                deleted.push_back( entry );
                                        }
                                }
                        }

                        // perform removals from mangle table, and deletions if necessary
                        for ( const auto& key : removed ) {
                                ++* stats().map_mutations;
                                mangleTable = mangleTable->erase( key );
                        }
                        if ( ! alreadyUserDefinedFunc ) for ( const auto& entry : deleted ) {
                                ++* stats().map_mutations;
                                mangleTable = mangleTable->set( entry.first, IdData{ entry.second, function } );
                        }
                } else if ( dataIsUserDefinedFunc ) {
                        // this is a user-defined non-copy function
                        // if this is the first user-defined function, delete non-user-defined overloads
                        std::vector< MangleTable::value_type > deleted;

                        for ( const auto& entry : * mangleTable ) {
                                // skip decls that aren't functions or are for the wrong type
                                const FunctionDecl * decl = getFunctionForOtype( entry.second.id, dataOtypeKey );
                                if ( ! decl ) continue;

                                // exit early if already a matching user-defined function;
                                // earlier function will have mutated table
                                if ( ! LinkageSpec::isOverridable( decl->linkage ) ) return true;

                                // skip mutating intrinsic functions
                                if ( decl->linkage == LinkageSpec::Intrinsic ) continue;

                                // user-defined non-copy functions do not override copy functions
                                if ( InitTweak::isCopyFunction( decl, decl->name ) ) continue;

                                // this function to be deleted after mangleTable iteration is complete
                                deleted.push_back( entry );
                        }

                        // mark deletions to update mangle table
                        // this needs to be a separate loop because of iterator invalidation
                        for ( const auto& entry : deleted ) {
                                ++* stats().map_mutations;
                                mangleTable = mangleTable->set( entry.first, IdData{ entry.second, function } );
                        }
                } else if ( function->linkage != LinkageSpec::Intrinsic ) {
                        // this is an overridable generated function
                        // if there already exists a matching user-defined function, delete this appropriately
                        for ( const auto& entry : * mangleTable ) {
                                // skip decls that aren't functions or are for the wrong type
                                const FunctionDecl * decl = getFunctionForOtype( entry.second.id, dataOtypeKey );
                                if ( ! decl ) continue;

                                // skip non-user-defined functions
                                if ( LinkageSpec::isOverridable( decl->linkage ) ) continue;

                                if ( dataIsCopyFunc ) {
                                        // remove current function if exists a user-defined copy function
                                        // since the signatures for copy functions don't need to match exactly, using
                                        // a delete statement is the wrong approach
                                        if ( InitTweak::isCopyFunction( decl, decl->name ) ) return false;
                                } else {
                                        // mark current function deleted by first user-defined function found
                                        data.deleteStmt = decl;
                                        return true;
                                }
                        }
                }

                // nothing (more) to fix, return true
                return true;
        }

        void Indexer::addId(const DeclarationWithType * decl, OnConflict handleConflicts, const Expression * baseExpr,
                        const Declaration * deleteStmt ) {
                ++* stats().add_calls;
                if ( ! trackIdentifiers ) return;
                const std::string &name = decl->name;
                if ( name == "" ) return;

                std::string mangleName;
                if ( LinkageSpec::isOverridable( decl->linkage ) ) {
                        // mangle the name without including the appropriate suffix, so overridable routines
                        // are placed into the same "bucket" as their user defined versions.
                        mangleName = Mangler::mangle( decl, false );
                } else {
                        mangleName = Mangler::mangle( decl );
                } // if

                // this ensures that no two declarations with the same unmangled name at the same scope
                // both have C linkage
                if ( LinkageSpec::isMangled( decl->linkage ) ) {
                        // Check that a Cforall declaration doesn't override any C declaration
                        if ( hasCompatibleCDecl( name, mangleName ) ) {
                                SemanticError( decl, "Cforall declaration hides C function " );
                        }
                } else {
                        // NOTE: only correct if name mangling is completely isomorphic to C
                        // type-compatibility, which it may not be.
                        if ( hasIncompatibleCDecl( name, mangleName ) ) {
                                SemanticError( decl, "conflicting overload of C function " );
                        }
                }

                // ensure tables exist and add identifier
                MangleTable::Ptr mangleTable;
                if ( ! idTable ) {
                        idTable = IdTable::new_ptr();
                        mangleTable = MangleTable::new_ptr();
                } else {
                        ++* stats().map_lookups;
                        auto decls = idTable->find( name );
                        if ( decls == idTable->end() ) {
                                mangleTable = MangleTable::new_ptr();
                        } else {
                                mangleTable = decls->second;
                                // skip in-scope repeat declarations of same identifier
                                ++* stats().map_lookups;
                                auto existing = mangleTable->find( mangleName );
                                if ( existing != mangleTable->end()
                                                && existing->second.scope == scope
                                                && existing->second.id ) {
                                        if ( addedIdConflicts( existing->second, decl, handleConflicts, deleteStmt ) ) {
                                                if ( handleConflicts.mode == OnConflict::Delete ) {
                                                        // set delete expression for conflicting identifier
                                                        lazyInitScope();
                                                        * stats().map_mutations += 2;
                                                        idTable = idTable->set(
                                                                name,
                                                                mangleTable->set(
                                                                        mangleName,
                                                                        IdData{ existing->second, handleConflicts.deleteStmt } ) );
                                                }
                                                return;
                                        }
                                }
                        }
                }

                // add/overwrite with new identifier
                lazyInitScope();
                IdData data{ decl, baseExpr, deleteStmt, scope };
                // Ensure that auto-generated ctor/dtor/assignment are deleted if necessary
                if ( ! removeSpecialOverrides( data, mangleTable ) ) return;
                * stats().map_mutations += 2;
                idTable = idTable->set( name, mangleTable->set( mangleName, std::move(data) ) );
        }

        void Indexer::addId( const DeclarationWithType * decl, const Expression * baseExpr ) {
                // default handling of conflicts is to raise an error
                addId( decl, OnConflict::error(), baseExpr, decl->isDeleted ? decl : nullptr );
        }

        void Indexer::addDeletedId( const DeclarationWithType * decl, const Declaration * deleteStmt ) {
                // default handling of conflicts is to raise an error
                addId( decl, OnConflict::error(), nullptr, deleteStmt );
        }

        bool addedTypeConflicts( const NamedTypeDecl * existing, const NamedTypeDecl * added ) {
                if ( existing->base == nullptr ) {
                        return false;
                } else if ( added->base == nullptr ) {
                        return true;
                } else {
                        assert( existing->base && added->base );
                        // typedef redeclarations are errors only if types are different
                        if ( ! ResolvExpr::typesCompatible( existing->base, added->base, Indexer() ) ) {
                                SemanticError( added->location, "redeclaration of " + added->name );
                        }
                }
                // does not need to be added to the table if both existing and added have a base that are
                // the same
                return true;
        }

        void Indexer::addType( const NamedTypeDecl * decl ) {
                ++* stats().add_calls;
                const std::string & id = decl->name;

                if ( ! typeTable ) {
                        typeTable = TypeTable::new_ptr();
                } else {
                        ++* stats().map_lookups;
                        auto existing = typeTable->find( id );
                        if ( existing != typeTable->end()
                                && existing->second.scope == scope
                                && addedTypeConflicts( existing->second.decl, decl ) ) return;
                }

                lazyInitScope();
                ++* stats().map_mutations;
                typeTable = typeTable->set( id, Scoped<NamedTypeDecl>{ decl, scope } );
        }

        bool addedDeclConflicts( const AggregateDecl * existing, const AggregateDecl * added ) {
                if ( ! existing->body ) {
                        return false;
                } else if ( added->body ) {
                        SemanticError( added, "redeclaration of " );
                } // if
                return true;
        }

        void Indexer::addStruct( const std::string & id ) {
                addStruct( new StructDecl( id ) );
        }

        void Indexer::addStruct( const StructDecl * decl ) {
                ++* stats().add_calls;
                const std::string & id = decl->name;

                if ( ! structTable ) {
                        structTable = StructTable::new_ptr();
                } else {
                        ++* stats().map_lookups;
                        auto existing = structTable->find( id );
                        if ( existing != structTable->end()
                                && existing->second.scope == scope
                                && addedDeclConflicts( existing->second.decl, decl ) ) return;
                }

                lazyInitScope();
                ++* stats().map_mutations;
                structTable = structTable->set( id, Scoped<StructDecl>{ decl, scope } );
        }

        void Indexer::addEnum( const EnumDecl * decl ) {
                ++* stats().add_calls;
                const std::string & id = decl->name;

                if ( ! enumTable ) {
                        enumTable = EnumTable::new_ptr();
                } else {
                        ++* stats().map_lookups;
                        auto existing = enumTable->find( id );
                        if ( existing != enumTable->end()
                                && existing->second.scope == scope
                                && addedDeclConflicts( existing->second.decl, decl ) ) return;
                }

                lazyInitScope();
                ++* stats().map_mutations;
                enumTable = enumTable->set( id, Scoped<EnumDecl>{ decl, scope } );
        }

        void Indexer::addUnion( const std::string & id ) {
                addUnion( new UnionDecl( id ) );
        }

        void Indexer::addUnion( const UnionDecl * decl ) {
                ++* stats().add_calls;
                const std::string & id = decl->name;

                if ( ! unionTable ) {
                        unionTable = UnionTable::new_ptr();
                } else {
                        ++* stats().map_lookups;
                        auto existing = unionTable->find( id );
                        if ( existing != unionTable->end()
                                && existing->second.scope == scope
                                && addedDeclConflicts( existing->second.decl, decl ) ) return;
                }

                lazyInitScope();
                ++* stats().map_mutations;
                unionTable = unionTable->set( id, Scoped<UnionDecl>{ decl, scope } );
        }

        void Indexer::addTrait( const TraitDecl * decl ) {
                ++* stats().add_calls;
                const std::string & id = decl->name;

                if ( ! traitTable ) {
                        traitTable = TraitTable::new_ptr();
                } else {
                        ++* stats().map_lookups;
                        auto existing = traitTable->find( id );
                        if ( existing != traitTable->end()
                                && existing->second.scope == scope
                                && addedDeclConflicts( existing->second.decl, decl ) ) return;
                }

                lazyInitScope();
                ++* stats().map_mutations;
                traitTable = traitTable->set( id, Scoped<TraitDecl>{ decl, scope } );
        }

        void Indexer::addMembers( const AggregateDecl * aggr, const Expression * expr, OnConflict handleConflicts ) {
                for ( Declaration * decl : aggr->members ) {
                        if ( DeclarationWithType * dwt = dynamic_cast< DeclarationWithType * >( decl ) ) {
                                addId( dwt, handleConflicts, expr );
                                if ( dwt->name == "" ) {
                                        const Type * t = dwt->get_type()->stripReferences();
                                        if ( dynamic_cast<const StructInstType *>( t ) || dynamic_cast<const UnionInstType *>( t ) ) {
                                                Expression * base = expr->clone();
                                                ResolvExpr::Cost cost = ResolvExpr::Cost::zero; // xxx - carry this cost into the indexer as a base cost?
                                                ResolvExpr::referenceToRvalueConversion( base, cost );
                                                addMembers( t->getAggr(), new MemberExpr( dwt, base ), handleConflicts );
                                        }
                                }
                        }
                }
        }

        void Indexer::addWith( const std::list< Expression * > & withExprs, const Declaration * withStmt ) {
                for ( const Expression * expr : withExprs ) {
                        if ( expr->result ) {
                                AggregateDecl * aggr = expr->result->stripReferences()->getAggr();
                                assertf( aggr, "WithStmt expr has non-aggregate type: %s", toString( expr->result ).c_str() );

                                addMembers( aggr, expr, OnConflict::deleteWith( withStmt ) );
                        }
                }
        }

        void Indexer::addIds( const std::list< DeclarationWithType * > & decls ) {
                for ( auto d : decls ) {
                        addId( d );
                }
        }

        void Indexer::addTypes( const std::list< TypeDecl * > & tds ) {
                for ( auto td : tds ) {
                        addType( td );
                        addIds( td->assertions );
                }
        }

        void Indexer::addFunctionType( const FunctionType * ftype ) {
                addTypes( ftype->forall );
                addIds( ftype->returnVals );
                addIds( ftype->parameters );
        }

        Expression * Indexer::IdData::combine( ResolvExpr::Cost & cost ) const {
                Expression * ret = nullptr;
                if ( baseExpr ) {
                        Expression * base = baseExpr->clone();
                        ResolvExpr::referenceToRvalueConversion( base, cost );
                        ret = new MemberExpr( const_cast<DeclarationWithType *>(id), base );
                        // xxx - this introduces hidden environments, for now remove them.
                        // std::swap( base->env, ret->env );
                        delete base->env;
                        base->env = nullptr;
                } else {
                        ret = new VariableExpr( const_cast<DeclarationWithType *>(id) );
                }
                if ( deleteStmt ) ret = new DeletedExpr( ret, const_cast<Declaration *>(deleteStmt) );
                return ret;
        }
} // namespace SymTab

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