source: src/Virtual/Tables.cc @ ecfd758

//
// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Tables.cc --
//
// Author           : Andrew Beach
// Created On       : Mon Aug 31 11:11:00 2020
// Last Modified By : Andrew Beach
// Last Modified On : Thr Apr  8 15:51:00 2021
// Update Count     : 1
//

#include <SynTree/Attribute.h>
#include <SynTree/Declaration.h>
#include <SynTree/Expression.h>
#include <SynTree/Statement.h>
#include <SynTree/Type.h>

namespace Virtual {

std::string typeIdType( std::string const & type_name ) {
        return "__cfatid_struct_" + type_name;
}

std::string typeIdName( std::string const & type_name ) {
        return "__cfatid_" + type_name;
}

static std::string typeIdTypeToInstance( std::string const & type_name ) {
        return typeIdName(type_name.substr(16));
}

std::string vtableTypeName( std::string const & name ) {
        return name + "_vtable";
}

std::string baseTypeName( std::string const & vtable_type_name ) {
        return vtable_type_name.substr(0, vtable_type_name.size() - 7);
}

std::string instanceName( std::string const & name ) {
        return std::string("_") + name + "_instance";
}

std::string vtableInstanceName( std::string const & name ) {
        return instanceName( vtableTypeName( name ) );
}

bool isVTableInstanceName( std::string const & name ) {
        // There are some delicate length calculations here.
        return 17 < name.size() && '_' == name[0] &&
                std::string("_vtable_instance") == name.substr(1, name.size() - 17);
}

static ObjectDecl * makeVtableDeclaration(
                StructInstType * type, Initializer * init ) {
        std::string const & name = instanceName( type->name );
        Type::StorageClasses storage = noStorageClasses;
        if ( nullptr == init ) {
                storage.is_extern = true;
        }
        return new ObjectDecl(
                name,
                storage,
                LinkageSpec::Cforall,
                nullptr,
                type,
                init
        );
}

ObjectDecl * makeVtableForward( StructInstType * type ) {
        assert( type );
        return makeVtableDeclaration( type, nullptr );
}

ObjectDecl * makeVtableInstance(
                StructInstType * vtableType, Type * objectType, Initializer * init ) {
        assert( vtableType );
        assert( objectType );
        StructDecl * vtableStruct = vtableType->baseStruct;
        // Build the initialization
        if ( nullptr == init ) {
                std::list< Initializer * > inits;

                // This is going to have to be run before the resolver to connect expressions.
                for ( auto field : vtableStruct->members ) {
                        if ( std::string( "parent" ) == field->name ) {
                                // This will not work with polymorphic state.
                                auto oField = strict_dynamic_cast< ObjectDecl * >( field );
                                auto fieldType = strict_dynamic_cast< PointerType * >( oField->type );
                                auto parentType = strict_dynamic_cast< StructInstType * >( fieldType->base );
                                std::string const & parentInstance = instanceName( parentType->name );
                                inits.push_back(
                                                new SingleInit( new AddressExpr( new NameExpr( parentInstance ) ) ) );
                        } else if ( std::string( "__cfavir_typeid" ) == field->name ) {
                                std::string const & baseType = baseTypeName( vtableType->name );
                                std::string const & typeId = typeIdName( baseType );
                                inits.push_back( new SingleInit( new AddressExpr( new NameExpr( typeId ) ) ) );
                        } else if ( std::string( "size" ) == field->name ) {
                                inits.push_back( new SingleInit( new SizeofExpr( objectType->clone() ) ) );
                        } else if ( std::string( "align" ) == field->name ) {
                                inits.push_back( new SingleInit( new AlignofExpr( objectType->clone() ) ) );
                        } else {
                                inits.push_back( new SingleInit( new NameExpr( field->name ) ) );
                        }
                }
                init = new ListInit( inits );
        // This should initialize everything except the parent pointer, the
        // size-of and align-of fields. These should be inserted.
        } else {
                assert(false);
        }
        return makeVtableDeclaration( vtableType, init );
}

namespace {
        std::string const functionName = "get_exception_vtable";
}

FunctionDecl * makeGetExceptionForward(
                Type * vtableType, Type * exceptType ) {
        assert( vtableType );
        assert( exceptType );
        FunctionType * type = new FunctionType( noQualifiers, false );
        vtableType->tq.is_const = true;
        type->returnVals.push_back( new ObjectDecl(
                "_retvalue",
                noStorageClasses,
                LinkageSpec::Cforall,
                nullptr,
                new ReferenceType( noQualifiers, vtableType ),
                nullptr,
        { new Attribute("unused") }
        ) );
        type->parameters.push_back( new ObjectDecl(
                "__unused",
                noStorageClasses,
                LinkageSpec::Cforall,
                nullptr,
                new PointerType( noQualifiers, exceptType ),
                nullptr,
                { new Attribute("unused") }
        ) );
        return new FunctionDecl(
                functionName,
                noStorageClasses,
                LinkageSpec::Cforall,
                type,
                nullptr
        );
}

FunctionDecl * makeGetExceptionFunction(
                ObjectDecl * vtableInstance, Type * exceptType ) {
        assert( vtableInstance );
        assert( exceptType );
        FunctionDecl * func = makeGetExceptionForward(
                vtableInstance->type->clone(), exceptType );
        func->statements = new CompoundStmt( {
                new ReturnStmt( new VariableExpr( vtableInstance ) ),
        } );
        return func;
}

ObjectDecl * makeTypeIdForward() {
        return nullptr;
}

Attribute * linkonce( const std::string & subsection ) {
        const std::string section = "\".gnu.linkonce." + subsection + "\"";
        // Adjust for terminator and quotes.
        size_t str_size = section.size() + 1 - 2;
        return new Attribute( "section", {
                new ConstantExpr( Constant(
                        new ArrayType(
                                noQualifiers,
                                new BasicType( noQualifiers, BasicType::Char ),
                                new ConstantExpr( Constant::from_ulong( str_size ) ),
                                false, false ),
                        section,
                        std::nullopt
                ) ),
        } );
}

ObjectDecl * makeTypeIdInstance( StructInstType const * typeIdType ) {
        assert( typeIdType );
        StructInstType * type = typeIdType->clone();
        type->tq.is_const = true;
        std::string const & typeid_name = typeIdTypeToInstance( typeIdType->name );
        return new ObjectDecl(
                typeid_name,
                noStorageClasses,
                LinkageSpec::Cforall,
                /* bitfieldWidth */ nullptr,
                type,
                new ListInit( { new SingleInit(
                        new AddressExpr( new NameExpr( "__cfatid_exception_t" ) )
                        ) } ),
                { linkonce( typeid_name ) },
                noFuncSpecifiers
        );
}

}