source: src/Virtual/Tables.cpp @ d96f7c4

//
// 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.cpp --
//
// Author           : Andrew Beach
// Created On       : Mon Aug 31 11:11:00 2020
// Last Modified By : Andrew Beach
// Last Modified On : Fri Mar 11 10:40:00 2022
// Update Count     : 3
//

#include "AST/Attribute.hpp"
#include "AST/Copy.hpp"
#include "AST/Decl.hpp"
#include "AST/Expr.hpp"
#include "AST/Init.hpp"
#include "AST/Stmt.hpp"
#include "AST/Type.hpp"

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 ) );
}

std::string concurrentDefaultVTableName() {
        return "_default_vtable";
}

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 ast::ObjectDecl * makeVtableDeclaration(
                CodeLocation const & location, std::string const & name,
                ast::StructInstType const * type, ast::Init const * init ) {
        ast::Storage::Classes storage;
        if ( nullptr == init ) {
                storage.is_extern = true;
        }
        return new ast::ObjectDecl(
                location,
                name,
                type,
                init,
                storage,
                ast::Linkage::Cforall
        );
}

ast::ObjectDecl * makeVtableForward(
                CodeLocation const & location, std::string const & name,
                ast::StructInstType const * vtableType ) {
        assert( vtableType );
        return makeVtableDeclaration( location, name, vtableType, nullptr );
}

static std::vector<ast::ptr<ast::Init>> buildInits(
                CodeLocation const & location,
                //std::string const & name,
                ast::StructInstType const * vtableType,
                ast::Type const * objectType ) {
        ast::StructDecl const * vtableStruct = vtableType->base;

        std::vector<ast::ptr<ast::Init>> inits;
        inits.reserve( vtableStruct->members.size() );

        // This is designed to run before the resolver.
        for ( auto field : vtableStruct->members ) {
                if ( std::string( "parent" ) == field->name ) {
                        // This will not work with polymorphic state.
                        auto oField = field.strict_as<ast::ObjectDecl>();
                        auto fieldType = oField->type.strict_as<ast::PointerType>();
                        auto parentType = fieldType->base.strict_as<ast::StructInstType>();
                        std::string const & parentInstance = instanceName( parentType->name );
                        inits.push_back(
                                        new ast::SingleInit( location, new ast::AddressExpr( new ast::NameExpr( location, 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 ast::SingleInit( location, new ast::AddressExpr( new ast::NameExpr( location, typeId ) ) ) );
                } else if ( std::string( "size" ) == field->name ) {
                        inits.push_back( new ast::SingleInit( location, new ast::SizeofExpr( location, objectType )
                        ) );
                } else if ( std::string( "align" ) == field->name ) {
                        inits.push_back( new ast::SingleInit( location,
                                new ast::AlignofExpr( location, objectType )
                        ) );
                } else {
                        inits.push_back( new ast::SingleInit( location,
                                new ast::NameExpr( location, field->name )
                        ) );
                }
        }

        return inits;
}

ast::ObjectDecl * makeVtableInstance(
                CodeLocation const & location,
                std::string const & name,
                ast::StructInstType const * vtableType,
                ast::Type const * objectType,
                ast::Init const * init ) {
        assert( vtableType );
        assert( objectType );

        // Build the initialization.
        if ( nullptr == init ) {
                init = new ast::ListInit( location,
                        buildInits( location, vtableType, objectType ) );

        // The provided init should initialize everything except the parent
        // pointer, the size-of and align-of fields. These should be inserted.
        } else {
                // Except this is not yet supported.
                assert(false);
        }
        return makeVtableDeclaration( location, name, vtableType, init );
}

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

ast::FunctionDecl * makeGetExceptionForward(
                CodeLocation const & location,
                ast::Type const * vtableType,
                ast::Type const * exceptType ) {
        assert( vtableType );
        assert( exceptType );

        // If this is called after Fix Return Statements (currently it is in
        // Implement Concurrent Keywords) then this must be marked as unused
        // to avoid warnings.
        ast::ObjectDecl * frontRet = new ast::ObjectDecl( location,
                "_retvalue",
                new ast::ReferenceType( vtableType )
        );
        frontRet->attributes.emplace_back( new ast::Attribute( "unused" ) );

        return new ast::FunctionDecl(
                location,
                functionName,
                { new ast::ObjectDecl(
                        location,
                        /* The parameter only exists to provide a type id. */ "",
                        new ast::PointerType( exceptType )
                ) },
                { frontRet },
                nullptr,
                ast::Storage::Classes(),
                ast::Linkage::Cforall,
                { new ast::Attribute( "unused" ) }
        );
}

ast::FunctionDecl * makeGetExceptionFunction(
                CodeLocation const & location,
                ast::ObjectDecl const * vtableInstance, ast::Type const * exceptType ) {
        assert( vtableInstance );
        assert( exceptType );
        ast::FunctionDecl * func = makeGetExceptionForward(
                        location, ast::deepCopy( vtableInstance->type ), exceptType );
        func->stmts = new ast::CompoundStmt( location, {
                new ast::ReturnStmt( location, new ast::VariableExpr( location, vtableInstance ) )
        } );
        return func;
}

ast::ObjectDecl * makeTypeIdInstance(
                CodeLocation const & location,
                ast::StructInstType const * typeIdType ) {
        assert( typeIdType );
        ast::StructInstType * type = ast::mutate( typeIdType );
        type->set_const( true );
        std::string const & typeid_name = typeIdTypeToInstance( typeIdType->name );
        return new ast::ObjectDecl(
                location,
                typeid_name,
                type,
                new ast::ListInit( location, {
                        new ast::SingleInit( location,
                                new ast::AddressExpr( location,
                                        new ast::NameExpr( location, "__cfatid_exception_t" ) ) )
                } ),
                ast::Storage::Classes(),
                ast::Linkage::Cforall,
                nullptr,
                { new ast::Attribute( "cfa_linkonce" ) }
        );
}

}