ValueIndex.h

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/*
 * Souffle - A Datalog Compiler
 * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved
 * Licensed under the Universal Permissive License v 1.0 as shown at:
 * - https://opensource.org/licenses/UPL
 * - <souffle root>/licenses/SOUFFLE-UPL.txt
 */
 
/************************************************************************
 *
 * @file ValueIndex.h
 *
 * Defines the ValueIndex class, which indexes the location of variables
 * and record references within a loop nest during rule conversion.
 *
 ***********************************************************************/
 
#pragma once
 
#include "souffle/utility/ContainerUtil.h"
#include <map>
#include <set>
#include <string>
#include <vector>
 
namespace souffle::ast {
class Argument;
class RecordInit;
class Variable;
}  // namespace souffle::ast
 
namespace souffle::ast2ram {
 
struct Location;
 
class ValueIndex {
public:
    ValueIndex();
    ~ValueIndex();
 
    /**
     * The type mapping variables (referenced by their names) to the
     * locations where they are used.
     */
    using variable_reference_map = std::map<std::string, std::set<Location>>;
 
    /**
     * The type mapping record init expressions to their definition points,
     * hence the point where they get grounded/bound.
     */
    using record_definition_map = std::map<const ast::RecordInit*, Location>;
 
    /**
     * A map from generative `ast::Argument`s to storage locations. Note,
     * since in this case ast::Argument are indexed by their values (not their
     * address) no standard map can be utilized.
     * (By-value indexing induces an ad-hoc form of CSE.)
     */
    using generator_location_map = std::vector<std::pair<const ast::Argument*, Location>>;
 
    // -- variables --
 
    const variable_reference_map& getVariableReferences() const {
        return var_references;
    }
 
    void addVarReference(const ast::Variable& var, const Location& l);
 
    void addVarReference(const ast::Variable& var, int ident, int pos, std::string rel = "");
 
    bool isDefined(const ast::Variable& var) const;
 
    const Location& getDefinitionPoint(const ast::Variable& var) const;
 
    // -- records --
 
    // - definition -
 
    void setRecordDefinition(const ast::RecordInit& init, const Location& l);
 
    void setRecordDefinition(const ast::RecordInit& init, int ident, int pos, std::string rel = "");
 
    const Location& getDefinitionPoint(const ast::RecordInit& init) const;
 
    // -- generators (aggregates & some functors) --
    void setGeneratorLoc(const ast::Argument& arg, const Location& loc);
 
    const Location& getGeneratorLoc(const ast::Argument& arg) const;
 
    // -- others --
 
    bool isGenerator(const int level) const;
 
    bool isSomethingDefinedOn(int level) const;
 
    void print(std::ostream& out) const;
 
private:
    /** The index of variable accesses */
    variable_reference_map var_references;
 
    /** The index of record definition points */
    record_definition_map record_definitions;
 
    /** The level of a nested ram operation that is handling a generator operation */
    generator_location_map arg_generator_locations;
};
 
}  // namespace souffle::ast2ram