source: src/GenPoly/ScrubTyVars.cc @ 7cf8006

//
// 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.
//
// ScrubTyVars.cc --
//
// Author           : Richard C. Bilson
// Created On       : Mon May 18 07:44:20 2015
// Last Modified By : Andrew Beach
// Last Modified On : Fri Oct  7 15:42:00 2022
// Update Count     : 5
//

#include <utility>                      // for pair

#include "AST/Pass.hpp"
#include "GenPoly.h"                    // for mangleType, TyVarMap, alignof...
#include "GenPoly/ErasableScopedMap.h"  // for ErasableScopedMap<>::const_it...
#include "ScrubTyVars.h"
#include "SymTab/Mangler.h"             // for mangleType
#include "SynTree/Declaration.h"        // for TypeDecl, TypeDecl::Data, Typ...
#include "SynTree/Expression.h"         // for Expression (ptr only), NameExpr
#include "SynTree/Mutator.h"            // for Mutator
#include "SynTree/Type.h"               // for PointerType, TypeInstType, Type

namespace GenPoly {
        Type * ScrubTyVars::postmutate( TypeInstType * typeInst ) {
                if ( ! tyVars ) {
                        if ( typeInst->get_isFtype() ) {
                                delete typeInst;
                                return new PointerType( Type::Qualifiers(), new FunctionType( Type::Qualifiers(), true ) );
                        } else {
                                PointerType * ret = new PointerType( Type::Qualifiers(), new VoidType( typeInst->get_qualifiers() ) );
                                delete typeInst;
                                return ret;
                        }
                }

                TyVarMap::const_iterator tyVar = tyVars->find( typeInst->name );
                if ( tyVar != tyVars->end() ) {
                        switch ( tyVar->second.kind ) {
                          case TypeDecl::Dtype:
                          case TypeDecl::Ttype:
                                {
                                        PointerType * ret = new PointerType( Type::Qualifiers(), new VoidType( typeInst->get_qualifiers() ) );
                                        delete typeInst;
                                        return ret;
                                }
                          case TypeDecl::Ftype:
                                delete typeInst;
                                return new PointerType( Type::Qualifiers(), new FunctionType( Type::Qualifiers(), true ) );
                          default:
                                assertf(false, "Unhandled tyvar kind: %d", tyVar->second.kind);
                        } // switch
                } // if
                return typeInst;
        }

        Type * ScrubTyVars::mutateAggregateType( Type * ty ) {
                if ( shouldScrub( ty ) ) {
                        PointerType * ret = new PointerType( Type::Qualifiers(), new VoidType( ty->get_qualifiers() ) );
                        delete ty;
                        return ret;
                }
                return ty;
        }

        Type * ScrubTyVars::postmutate( StructInstType * structInst ) {
                return mutateAggregateType( structInst );
        }

        Type * ScrubTyVars::postmutate( UnionInstType * unionInst ) {
                return mutateAggregateType( unionInst );
        }

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

        Expression * ScrubTyVars::postmutate( SizeofExpr * szeof ) {
                // sizeof( T ) => _sizeof_T parameter, which is the size of T
                if ( dynType ) {
                        Expression *expr = new NameExpr( sizeofName( mangleType( dynType ) ) );
                        return expr;
                } // if
                return szeof;
        }

        Expression * ScrubTyVars::postmutate( AlignofExpr * algnof ) {
                // alignof( T ) => _alignof_T parameter, which is the alignment of T
                if ( dynType ) {
                        Expression *expr = new NameExpr( alignofName( mangleType( dynType ) ) );
                        return expr;
                } // if
                return algnof;
        }

        Type * ScrubTyVars::postmutate( PointerType * pointer ) {
                if ( dynType ) {
                        Type * ret = dynType->acceptMutator( *visitor );
                        ret->get_qualifiers() |= pointer->get_qualifiers();
                        pointer->base = nullptr;
                        delete pointer;
                        return ret;
                }
                return pointer;
        }

namespace {

enum class ScrubMode {
        FromMap,
        DynamicFromMap,
        All,
};

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 ) {
        // This implies that mode == ScrubMode::All.
        if ( !typeVars ) {
                if ( ast::TypeDecl::Ftype == type->kind ) {
                        return new ast::PointerType(
                                new ast::FunctionType( ast::FixedArgs ) );
                } else {
                        return new ast::PointerType(
                                new ast::VoidType( type->qualifiers ) );
                }
        }

        auto typeVar = typeVars->find( *type );
        if ( typeVar == typeVars->end() ) {
                return type;
        }

        switch ( typeVar->second.kind ) {
        case ::TypeDecl::Dtype:
        case ::TypeDecl::Ttype:
                return new ast::PointerType(
                        new ast::VoidType( type->qualifiers ) );
        case ::TypeDecl::Ftype:
                return new ast::PointerType(
                        new ast::FunctionType( ast::VariableArgs ) );
        default:
                assertf( false,
                        "Unhandled type variable kind: %d", typeVar->second.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;
        }
}

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

} // namespace

template<>
ast::Node const * scrubTypeVars<ast::Node>(
        const ast::Node * target, const TypeVarMap & typeVars ) {
        return scrubTypeVarsBase( target, ScrubMode::FromMap, &typeVars );
}

template<>
ast::Node const * scrubTypeVarsDynamic<ast::Node>(
        ast::Node const * target, const TypeVarMap & typeVars ) {
        return scrubTypeVarsBase( target, ScrubMode::DynamicFromMap, &typeVars );
}

template<>
ast::Node const * scrubAllTypeVars<ast::Node>( const ast::Node * target ) {
        return scrubTypeVarsBase( target, ScrubMode::All, nullptr );
}

} // namespace GenPoly

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