source: src/Validate/HoistStruct.cpp

//
// Cforall Version 1.0.0 Copyright (C) 2018 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// HoistStruct.cpp -- Flattens nested type declarations.
//
// Author           : Andrew Beach
// Created On       : Thr Apr 21 10:34:00 2022
// Last Modified By : Andrew Beach
// Last Modified On : Thr Apr 21 10:34:00 2022
// Update Count     : 0
//

#include "Validate/HoistStruct.hpp"

#include <sstream>

#include "AST/DeclReplacer.hpp"
#include "AST/Pass.hpp"
#include "AST/TranslationUnit.hpp"
#include "AST/Vector.hpp"

namespace Validate {

namespace {

/// Is this a declaration can appear in a struct/union and should be hoisted?
bool shouldHoist( ast::Decl const * decl ) {
        return dynamic_cast< ast::StructDecl const * >( decl )
                || dynamic_cast< ast::UnionDecl const * >( decl )
                || dynamic_cast< ast::EnumDecl const * >( decl )
                || dynamic_cast< ast::StaticAssertDecl const * >( decl );
}

/// Helper that updates an InstType if the base name could be updated.
template<typename InstType>
InstType const * preInstType( InstType const * type ) {
        assert( type->base );
        if ( nullptr == type->base->parent ) return type;
        auto mut = ast::mutate( type );
        mut->name = mut->base->name;
        return mut;
}

/// Update StructInstType and UnionInstType names.
struct NameUpdater {
        ast::StructInstType const * previsit( ast::StructInstType const * type ) {
                return preInstType( type );
        }

        ast::UnionInstType const * previsit( ast::UnionInstType const * type ) {
                return preInstType( type );
        }
};

ast::Decl const * updateNames( ast::Decl const * decl ) {
        ast::Pass<NameUpdater> visitor;
        return decl->accept( visitor );
}

/* This pass hoists from structs/unions. Hoisted declarations should always
 * appear before the declaration they are hoisted out of and if two types are
 * nested in the same declaration their order should not change.
 * It also sets up parent relationships, does name mangling of hoisted types
 * and updates instance types of the hoisted types.
 */
struct HoistStructCore final :
                public ast::WithDeclsToAdd<>, public ast::WithGuards {
        ast::StructDecl const * previsit( ast::StructDecl const * decl );
        ast::StructDecl const * postvisit( ast::StructDecl const * decl );
        ast::UnionDecl const * previsit( ast::UnionDecl const * decl );
        ast::UnionDecl const * postvisit( ast::UnionDecl const * decl );
        ast::StructInstType const * previsit( ast::StructInstType const * type );
        ast::UnionInstType const * previsit( ast::UnionInstType const * type );
        ast::EnumInstType const * previsit( ast::EnumInstType const * type );

private:
        template<typename AggrDecl>
        AggrDecl const * preAggregate( AggrDecl const * );
        template<typename AggrDecl>
        AggrDecl const * postAggregate( AggrDecl const * );
        template<typename InstType>
        InstType const * preCollectionInstType( InstType const * type );

        ast::AggregateDecl const * parent = nullptr;
};

void qualifiedName( ast::AggregateDecl const * decl, std::ostringstream & ss ) {
        if ( decl->parent ) {
                qualifiedName( decl->parent, ss );
        }
        ss << "__" << decl->name;
}

std::string qualifiedName( ast::AggregateDecl const * decl ) {
        std::ostringstream ss;
        qualifiedName( decl, ss );
        return ss.str();
}

void extendParams( ast::vector<ast::TypeDecl> & dstParams,
                ast::vector<ast::TypeDecl> const & srcParams ) {
        if ( srcParams.empty() ) return;

        ast::DeclReplacer::TypeMap newToOld;
        ast::vector<ast::TypeDecl> params;
        for ( ast::ptr<ast::TypeDecl> const & srcParam : srcParams ) {
                ast::TypeDecl * dstParam = ast::deepCopy( srcParam.get() );
                dstParam->init = nullptr;
                newToOld.emplace( srcParam, dstParam );
                for ( auto assertion : dstParam->assertions ) {
                        assertion = ast::DeclReplacer::replace( assertion, newToOld );
                }
                params.emplace_back( dstParam );
        }
        spliceBegin( dstParams, params );
}

template<typename AggrDecl>
AggrDecl const * HoistStructCore::preAggregate( AggrDecl const * decl ) {
        if ( parent ) {
                auto mut = ast::mutate( decl );
                mut->parent = parent;
                extendParams( mut->params, parent->params );
                decl = mut;
        }
        GuardValue( parent ) = decl;
        return decl;
}

template<typename AggrDecl>
AggrDecl const * HoistStructCore::postAggregate( AggrDecl const * decl ) {
        auto mut = ast::mutate( decl );
        for ( auto it = mut->members.begin() ; it != mut->members.end() ; ) {
                if ( shouldHoist( *it ) ) {
                        // This is the place where the actual hoisting happens.
                        declsToAddBefore.push_back( it->get() );
                        it = mut->members.erase( it );
                } else {
                        ++it;
                }
        }
        // Is this a nested type? Then update the name, after the parent's name
        // has been updated (hence the post visit).
        if ( mut->parent ) {
                mut->name = qualifiedName( mut );
        // Top level type that has hoisted? Then do a second pass subpass to make
        // sure we update instance type names after the declaration is renamed.
        } else if ( !declsToAddBefore.empty() ) {
                for ( ast::ptr<ast::Decl> & member : mut->members ) {
                        member = updateNames( member.get() );
                }
                for ( ast::ptr<ast::Decl> & declToAdd : declsToAddBefore ) {
                        declToAdd = updateNames( declToAdd );
                }
        }
        return mut;
}

ast::StructDecl const * HoistStructCore::previsit( ast::StructDecl const * decl ) {
        return preAggregate( decl );
}

ast::StructDecl const * HoistStructCore::postvisit( ast::StructDecl const * decl ) {
        return postAggregate( decl );
}

ast::UnionDecl const * HoistStructCore::previsit( ast::UnionDecl const * decl ) {
        return preAggregate( decl );
}

ast::UnionDecl const * HoistStructCore::postvisit( ast::UnionDecl const * decl ) {
        return postAggregate( decl );
}

ast::AggregateDecl const * commonParent(
                ast::AggregateDecl const * lhs, ast::AggregateDecl const * rhs ) {
        for ( auto outer = lhs ; outer ; outer = outer->parent ) {
                for ( auto inner = rhs ; inner ; inner = inner->parent ) {
                        if ( outer == inner ) {
                                return outer;
                        }
                }
        }
        return nullptr;
}

template<typename InstType>
InstType const * HoistStructCore::preCollectionInstType( InstType const * type ) {
        if ( !type->base->parent ) return type;
        if ( type->base->params.empty() ) return type;

        InstType * mut = ast::mutate( type );
        ast::AggregateDecl const * parent =
                commonParent( this->parent, mut->base->parent );
        assert( parent );

        std::vector<ast::ptr<ast::Expr>> args;
        for ( const ast::ptr<ast::TypeDecl> & param : parent->params ) {
                args.emplace_back( new ast::TypeExpr( param->location,
                        new ast::TypeInstType( param )
                ) );
        }
        spliceBegin( mut->params, args );
        return mut;
}

ast::StructInstType const * HoistStructCore::previsit( ast::StructInstType const * type ) {
        return preInstType( preCollectionInstType( type ) );
}

ast::UnionInstType const * HoistStructCore::previsit( ast::UnionInstType const * type ) {
        return preInstType( preCollectionInstType( type ) );
}

ast::EnumInstType const * HoistStructCore::previsit( ast::EnumInstType const * type ) {
        return preInstType( type );
}

} // namespace

void hoistStruct( ast::TranslationUnit & translationUnit ) {
        ast::Pass<HoistStructCore>::run( translationUnit );
}

} // namespace Validate

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