source: src/ResolvExpr/RenameVars.cc @ 35897fb

//
// 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.
//
// RenameVars.cc --
//
// Author           : Richard C. Bilson
// Created On       : Sun May 17 12:05:18 2015
// Last Modified By : Andrew Beach
// Last Modified On : Thr Jun 20 17:39:00 2019
// Update Count     : 8
//

#include <ext/alloc_traits.h>      // for __alloc_traits<>::value_type
#include <memory>                  // for allocator_traits<>::value_type
#include <sstream>                 // for operator<<, basic_ostream, ostring...
#include <utility>                 // for pair

#include "AST/Pass.hpp"
#include "AST/Type.hpp"
#include "Common/ScopedMap.h"
#include "Common/SemanticError.h"  // for SemanticError
#include "RenameVars.h"

#include "AST/Copy.hpp"

namespace ResolvExpr {

namespace {

class RenamingData {
        int level = 0;
        int resetCount = 0;

        int next_expr_id = 1;
        int next_usage_id = 1;
        ScopedMap< std::string, std::string > nameMap;
        ScopedMap< std::string, ast::TypeEnvKey > idMap;
public:
        void reset() {
                level = 0;
                ++resetCount;
        }

        void nextUsage() {
                ++next_usage_id;
        }

        const ast::TypeInstType * rename( const ast::TypeInstType * type ) {
                auto it = idMap.find( type->name );
                if ( it == idMap.end() ) return type;

                // Unconditionally mutate because map will *always* have different name.
                ast::TypeInstType * mut = ast::shallowCopy( type );
                // Reconcile base node since some copies might have been made.
                mut->base = it->second.base;
                mut->formal_usage = it->second.formal_usage;
                mut->expr_id = it->second.expr_id;
                return mut;
        }

        const ast::FunctionType * openLevel( const ast::FunctionType * type, RenameMode mode ) {
                if ( type->forall.empty() ) return type;
                idMap.beginScope();

                // Load new names from this forall clause and perform renaming.
                auto mutType = ast::shallowCopy( type );
                // assert( type == mutType && "mutated type must be unique from ForallSubstitutor" );
                for ( auto & td : mutType->forall ) {
                        auto mut = ast::shallowCopy( td.get() );
                        // assert( td == mutDecl && "mutated decl must be unique from ForallSubstitutor" );

                        if ( mode == GEN_EXPR_ID ) {
                                mut->expr_id = next_expr_id;
                                mut->formal_usage = -1;
                                ++next_expr_id;
                        } else if ( mode == GEN_USAGE ) {
                                assertf( mut->expr_id, "unfilled expression id in generating candidate type" );
                                mut->formal_usage = next_usage_id;
                        } else {
                                assert(false);
                        }
                        idMap[ td->name ] = ast::TypeEnvKey( *mut );

                        td = mut;
                }

                return mutType;
        }

        void closeLevel( const ast::FunctionType * type ) {
                if ( type->forall.empty() ) return;
                idMap.endScope();
        }
};

// Global State:
RenamingData renaming;

struct RenameVars final : public ast::PureVisitor /*: public ast::WithForallSubstitutor*/ {
        RenameMode mode;

        const ast::FunctionType * previsit( const ast::FunctionType * type ) {
                return renaming.openLevel( type, mode );
        }

        /*
        const ast::StructInstType * previsit( const ast::StructInstType * type ) {
                return renaming.openLevel( type );
        }
        const ast::UnionInstType * previsit( const ast::UnionInstType * type ) {
                return renaming.openLevel( type );
        }
        const ast::TraitInstType * previsit( const ast::TraitInstType * type ) {
                return renaming.openLevel( type );
        }
        */

        const ast::TypeInstType * previsit( const ast::TypeInstType * type ) {
                // Do not rename an actual type.
                if ( mode == GEN_USAGE && !type->formal_usage ) return type;
                return renaming.rename( type );
        }
        void postvisit( const ast::FunctionType * type ) {
                renaming.closeLevel( type );
        }
};

} // namespace

const ast::Type * renameTyVars( const ast::Type * t, RenameMode mode, bool reset ) {
        ast::Pass<RenameVars> renamer;
        renamer.core.mode = mode;
        if (mode == GEN_USAGE && reset) {
                renaming.nextUsage();
        }
        return t->accept( renamer );
}

void resetTyVarRenaming() {
        renaming.reset();
        renaming.nextUsage();
}

} // namespace ResolvExpr

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