source: src/GenPoly/ScrubTypeVars.cpp

//
// 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.
//
// ScrubTypeVars.cpp -- Remove polymorphic types.
//
// Author           : Richard C. Bilson
// Created On       : Mon May 18 07:44:20 2015
// Last Modified By : Andrew Beach
// Last Modified On : Wed Dec  7 17:01:00 2022
// Update Count     : 6
//

#include "ScrubTypeVars.hpp"

#include <utility>                        // for pair

#include "AST/Pass.hpp"
#include "GenPoly.hpp"                    // for mangleType, TyVarMap, align...
#include "GenPoly/ErasableScopedMap.hpp"  // for ErasableScopedMap<>::const_...
#include "SymTab/Mangler.hpp"             // for mangleType

namespace GenPoly {

namespace {

struct ScrubTypeVars :
                public ast::WithGuards,
                public ast::WithShortCircuiting,
                public ast::WithVisitorRef<ScrubTypeVars> {

        ScrubTypeVars( ScrubMode m, TypeVarMap const * tv ) :
                        mode ( m ), typeVars( tv ) {}

        void previsit( ast::TypeInstType const * ) { visit_children = false; }
        void previsit( ast::StructInstType const * ) { visit_children = false; }
        void previsit( ast::UnionInstType const * ) { visit_children = false; }
        void previsit( ast::SizeofExpr const * expr ) { primeBaseScrub( expr->type ); }
        void previsit( ast::AlignofExpr const * expr ) { primeBaseScrub( expr->type ); }
        void previsit( ast::PointerType const * type ) { primeBaseScrub( type->base ); }

        ast::Type const * postvisit( ast::TypeInstType const * type );
        ast::Type const * postvisit( ast::StructInstType const * type );
        ast::Type const * postvisit( ast::UnionInstType const * type );
        ast::Expr const * postvisit( ast::SizeofExpr const * expr );
        ast::Expr const * postvisit( ast::AlignofExpr const * expr );
        ast::Type const * postvisit( ast::PointerType const * type );

private:
        ScrubMode const mode;
        /// Type varriables to scrub.
        TypeVarMap const * const typeVars;
        /// Value cached by primeBaseScrub.
        ast::Type const * dynType = nullptr;

        /// Returns the type if it should be scrubbed, nullptr otherwise.
        ast::Type const * shouldScrub( ast::Type const * type ) {
                switch ( mode ) {
                case ScrubMode::FromMap:
                        return isPolyType( type, *typeVars );
                case ScrubMode::DynamicFromMap:
                        return isDynType( type, *typeVars );
                case ScrubMode::All:
                        return isPolyType( type );
                default:
                        assertf( false, "Invalid ScrubMode in shouldScrub." );
                        throw;
                }
        }

        void primeBaseScrub( ast::Type const * type ) {
                // Need to determine whether type needs to be scrubbed to
                // determine whether automatic recursion is necessary.
                if ( ast::Type const * t = shouldScrub( type ) ) {
                        visit_children = false;
                        GuardValue( dynType ) = t;
                }
        }

        ast::Type const * postvisitAggregateType(
                        ast::BaseInstType const * type ) {
                if ( !shouldScrub( type ) ) return type;
                return new ast::PointerType( new ast::VoidType( type->qualifiers ) );
        }
};

ast::Type const * ScrubTypeVars::postvisit( ast::TypeInstType const * type ) {
        ast::TypeDecl::Kind kind;
        // This implies that mode == ScrubMode::All.
        if ( !typeVars ) {
                kind = type->kind;
        } else {
                // Otherwise, only scrub the type var if it is in map.
                auto typeVar = typeVars->find( *type );
                if ( typeVar == typeVars->end() ) {
                        return type;
                }
                kind = typeVar->second.kind;
        }

        switch ( kind ) {
        case ast::TypeDecl::Dtype:
        case ast::TypeDecl::Ttype:
                return new ast::PointerType(
                        new ast::VoidType( type->qualifiers ) );
        case ast::TypeDecl::Ftype:
                return new ast::PointerType(
                        new ast::FunctionType( ast::VariableArgs ) );
        default:
                assertf( false, "Unhandled type variable kind: %d", kind );
                throw; // Just in case the assert is removed, stop here.
        }
}

ast::Type const * ScrubTypeVars::postvisit( ast::StructInstType const * type ) {
        return postvisitAggregateType( type );
}

ast::Type const * ScrubTypeVars::postvisit( ast::UnionInstType const * type ) {
        return postvisitAggregateType( type );
}

ast::Expr const * ScrubTypeVars::postvisit( ast::SizeofExpr const * expr ) {
        // sizeof( T ) becomes the _sizeof_T parameter.
        if ( dynType ) {
                return new ast::NameExpr( expr->location,
                        sizeofName( Mangle::mangleType( dynType ) ) );
        } else {
                return expr;
        }
}

ast::Expr const * ScrubTypeVars::postvisit( ast::AlignofExpr const * expr ) {
        // alignof( T ) becomes the _alignof_T parameter.
        if ( dynType ) {
                return new ast::NameExpr( expr->location,
                        alignofName( Mangle::mangleType( dynType ) ) );
        } else {
                return expr;
        }
}

ast::Type const * ScrubTypeVars::postvisit( ast::PointerType const * type ) {
        if ( dynType ) {
                ast::Type * ret = ast::mutate( dynType->accept( *visitor ) );
                ret->qualifiers |= type->qualifiers;
                return ret;
        } else {
                return type;
        }
}

} // namespace

const ast::Node * scrubTypeVarsBase(
                const ast::Node * node, const TypeVarMap * typeVars, ScrubMode mode ) {
        if ( ScrubMode::All == mode ) {
                assert( nullptr == typeVars );
        } else {
                assert( nullptr != typeVars );
        }
        ast::Pass<ScrubTypeVars> visitor( mode, typeVars );
        return node->accept( visitor );
}

} // namespace GenPoly

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