source: src/ResolvExpr/AlternativeFinder.h@ 47498bd

//
// 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.
//
// AlternativeFinder.h --
//
// Author           : Richard C. Bilson
// Created On       : Sat May 16 23:56:12 2015
// Last Modified By : Andrew Beach
// Last Modified On : Wed Jul 26 11:24:00 2017
// Update Count     : 4
//

#pragma once

#include <algorithm>                     // for copy
#include <list>                          // for list
#include <string>                        // for string

#include "Alternative.h"                 // for AltList, Alternative
#include "ExplodedActual.h"              // for ExplodedActual
#include "ResolvExpr/Cost.h"             // for Cost, Cost::infinity
#include "ResolvExpr/TypeEnvironment.h"  // for AssertionSet, OpenVarSet
#include "SynTree/Visitor.h"             // for Visitor
#include "SynTree/SynTree.h"             // for Visitor Nodes

namespace SymTab {
class Indexer;
}  // namespace SymTab

namespace ResolvExpr {
        struct ArgPack;

        /// First index is which argument, second index is which alternative for that argument,
        /// third index is which exploded element of that alternative
        using ExplodedArgs = std::vector< std::vector< ExplodedActual > >;

        class AlternativeFinder {
          public:
                AlternativeFinder( const SymTab::Indexer &indexer, const TypeEnvironment &env );

                AlternativeFinder( const AlternativeFinder& o )
                        : indexer(o.indexer), alternatives(o.alternatives), env(o.env),
                          targetType(o.targetType) {}

                AlternativeFinder( AlternativeFinder&& o )
                        : indexer(o.indexer), alternatives(std::move(o.alternatives)), env(o.env),
                          targetType(o.targetType) {}

                AlternativeFinder& operator= ( const AlternativeFinder& o ) {
                        if (&o == this) return *this;

                        // horrific nasty hack to rebind references...
                        alternatives.~AltList();
                        new(this) AlternativeFinder(o);
                        return *this;
                }

                AlternativeFinder& operator= ( AlternativeFinder&& o ) {
                        if (&o == this) return *this;

                        // horrific nasty hack to rebind references...
                        alternatives.~AltList();
                        new(this) AlternativeFinder(std::move(o));
                        return *this;
                }

                void find( Expression *expr, bool adjust = false, bool prune = true, bool failFast = true );
                /// Calls find with the adjust flag set; adjustment turns array and function types into equivalent pointer types
                void findWithAdjustment( Expression *expr );
                /// Calls find with the adjust flag set and prune flag unset; pruning ensures there is at most one alternative per result type
                void findWithoutPrune( Expression *expr );
                /// Calls find with the adjust and prune flags set, failFast flags unset; fail fast ensures that there is at least one resulting alternative
                void maybeFind( Expression *expr );
                AltList &get_alternatives() { return alternatives; }

                // make this look like an STL container so that we can apply generic algorithms
                typedef Alternative value_type;
                typedef AltList::iterator iterator;
                typedef AltList::const_iterator const_iterator;
                AltList::iterator begin() { return alternatives.begin(); }
                AltList::iterator end() { return alternatives.end(); }
                AltList::const_iterator begin() const { return alternatives.begin(); }
                AltList::const_iterator end() const { return alternatives.end(); }

                const SymTab::Indexer &get_indexer() const { return indexer; }
                const TypeEnvironment &get_environ() const { return env; }

                /// Runs a new alternative finder on each element in [begin, end)
                /// and writes each alternative finder to out.
                template< typename InputIterator, typename OutputIterator >
                void findSubExprs( InputIterator begin, InputIterator end, OutputIterator out );
          private:
                struct Finder;
                const SymTab::Indexer &indexer;
                AltList alternatives;
                const TypeEnvironment &env;
                Type * targetType = nullptr;
        }; // AlternativeFinder

        Expression *resolveInVoidContext( Expression *expr, const SymTab::Indexer &indexer, TypeEnvironment &env );

        template< typename InputIterator, typename OutputIterator >
        void findMinCost( InputIterator begin, InputIterator end, OutputIterator out ) {
                AltList alternatives;

                // select the alternatives that have the minimum parameter cost
                Cost minCost = Cost::infinity;
                for ( InputIterator i = begin; i != end; ++i ) {
                        if ( i->cost < minCost ) {
                                minCost = i->cost;
                                i->cost = i->cvtCost;
                                alternatives.clear();
                                alternatives.push_back( *i );
                        } else if ( i->cost == minCost ) {
                                i->cost = i->cvtCost;
                                alternatives.push_back( *i );
                        }
                }
                std::copy( alternatives.begin(), alternatives.end(), out );
        }

        Cost sumCost( const AltList &in );
        void printAlts( const AltList &list, std::ostream &os, unsigned int indentAmt = 0 );

        /// Adds type variables to the open variable set and marks their assertions
        void makeUnifiableVars( Type *type, OpenVarSet &unifiableVars, AssertionSet &needAssertions );

        template< typename InputIterator >
        void simpleCombineEnvironments( InputIterator begin, InputIterator end, TypeEnvironment &result ) {
                while ( begin != end ) {
                        result.simpleCombine( (*begin++).env );
                }
        }

} // namespace ResolvExpr

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