source: src/Validate/LinkInstanceTypes.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.
//
// LinkInstanceTypes.cpp -- Connect instance types to declarations.
//
// Author           : Andrew Beach
// Created On       : Thr Apr 21 11:41:00 2022
// Last Modified By : Andrew Beach
// Last Modified On : Fri Jul 14  9:19:00 2023
// Update Count     : 3
//

#include "Validate/LinkInstanceTypes.hpp"

#include "AST/Pass.hpp"
#include "AST/TranslationUnit.hpp"
#include "Validate/ForallPointerDecay.hpp"
#include "Validate/NoIdSymbolTable.hpp"

namespace Validate {

namespace {

struct LinkTypesCore : public WithNoIdSymbolTable,
                public ast::WithCodeLocation,
                public ast::WithDeclsToAdd<>,
                public ast::WithGuards,
                public ast::WithShortCircuiting,
                public ast::WithVisitorRef<LinkTypesCore> {
        ast::TypeInstType const * postvisit( ast::TypeInstType const * type );
        ast::EnumInstType const * postvisit( ast::EnumInstType const * type );
        ast::StructInstType const * postvisit( ast::StructInstType const * type );
        ast::UnionInstType const * postvisit( ast::UnionInstType const * type );
        ast::TraitInstType const * postvisit( ast::TraitInstType const * type );
        void previsit( ast::QualifiedType const * type );
        void postvisit( ast::QualifiedType const * type );

        ast::EnumDecl const * postvisit( ast::EnumDecl const * decl );
        ast::StructDecl const * previsit( ast::StructDecl const * decl );
        void postvisit( ast::StructDecl const * decl );
        ast::UnionDecl const * previsit( ast::UnionDecl const * decl );
        void postvisit( ast::UnionDecl const * decl );
        ast::TraitDecl const * postvisit( ast::TraitDecl const * decl );

private:
        using ForwardStructsType =
                std::map< std::string, std::list< ast::StructInstType * > >;
        using ForwardUnionsType =
                std::map< std::string, std::list< ast::UnionInstType * > >;
        using ForwardEnumsType =
                std::map< std::string, std::list< ast::EnumInstType * > >;

        ForwardStructsType forwardStructs;
        ForwardUnionsType forwardUnions;
        ForwardEnumsType forwardEnums;

        /// true if currently in a generic type body,
        /// so that type parameter instances can be renamed appropriately
        bool inGeneric = false;

        template<typename AggrDecl>
        AggrDecl const * renameGenericParams( AggrDecl const * decl );

        // This cluster is used to add declarations (before) but outside of
        // any "namespaces" which would qualify the names.
        bool inNamespace = false;
        std::list<ast::ptr<ast::Decl>> declsToAddOutside;
        /// The "leaveNamespace" is handled by guard.
        void enterNamespace();
        /// Puts the decl on the back of declsToAddAfter once traversal is
        /// outside of any namespaces.
        void addDeclAfterOutside( ast::Decl const * );
};

void LinkTypesCore::enterNamespace() {
        if ( inNamespace ) return;
        inNamespace = true;
        GuardAction( [this](){
                inNamespace = false;
                declsToAddAfter.splice( declsToAddAfter.begin(), declsToAddOutside );
        } );
}

void LinkTypesCore::addDeclAfterOutside( ast::Decl const * decl ) {
        if ( inNamespace ) {
                declsToAddOutside.emplace_back( decl );
        } else {
                declsToAddAfter.emplace_back( decl );
        }
}

ast::TypeInstType const * LinkTypesCore::postvisit( ast::TypeInstType const * type ) {
        auto mut = ast::mutate( type );
        if ( inGeneric && mut->base ) {
                mut->name = mut->base->name;
        }
        if ( auto namedTypeDecl = symtab.lookupType( mut->name ) ) {
                if ( auto typeDecl = dynamic_cast<ast::TypeDecl const *>( namedTypeDecl ) ) {
                        mut->kind = typeDecl->kind;
                }
        }
        return mut;
}

ast::EnumInstType const * LinkTypesCore::postvisit( ast::EnumInstType const * type ) {
        ast::EnumDecl const * decl = symtab.lookupEnum( type->name );
        // It's not a semantic error if the enum is not found, just an implicit forward declaration.
        // The unset code location is used to detect imaginary declarations.
        // (They may never be used for enumerations.)
        if ( !decl || decl->location.isUnset() ) {
                assert( location );
                ast::EnumDecl * mut = new ast::EnumDecl( *location, type->name );
                mut->linkage = ast::Linkage::Compiler;
                decl = mut;
                symtab.addEnum( decl );
                addDeclAfterOutside( decl );
        }

        ast::EnumInstType * mut = ast::mutate( type );

        // Just linking in the node.
        mut->base = decl;

        if ( !decl->body ) {
                forwardEnums[ mut->name ].push_back( mut );
        }
        return mut;
}

ast::StructInstType const * LinkTypesCore::postvisit( ast::StructInstType const * type ) {
        ast::StructDecl const * decl = symtab.lookupStruct( type->name );
        // It's not a semantic error if the struct is not found, just an implicit forward declaration.
        // The unset code location is used to detect imaginary declarations.
        if ( !decl || decl->location.isUnset() ) {
                assert( location );
                ast::StructDecl * mut = new ast::StructDecl( *location, type->name );
                mut->linkage = ast::Linkage::Compiler;
                decl = mut;
                symtab.addStruct( decl );
                addDeclAfterOutside( decl );
        }

        ast::StructInstType * mut = ast::mutate( type );

        // Just linking in the node.
        mut->base = decl;

        if ( !decl->body ) {
                forwardStructs[ mut->name ].push_back( mut );
        }
        return mut;
}

ast::UnionInstType const * LinkTypesCore::postvisit( ast::UnionInstType const * type ) {
        ast::UnionDecl const * decl = symtab.lookupUnion( type->name );
        // It's not a semantic error if the union is not found, just an implicit forward declaration.
        // The unset code location is used to detect imaginary declarations.
        if ( !decl || decl->location.isUnset() ) {
                assert( location );
                ast::UnionDecl * mut = new ast::UnionDecl( *location, type->name );
                mut->linkage = ast::Linkage::Compiler;
                decl = mut;
                symtab.addUnion( decl );
                addDeclAfterOutside( decl );
        }

        ast::UnionInstType * mut = ast::mutate( type );

        // Just linking in the node.
        mut->base = decl;

        if ( !decl->body ) {
                forwardUnions[ mut->name ].push_back( mut );
        }
        return mut;
}

ast::TraitInstType const * LinkTypesCore::postvisit( ast::TraitInstType const * type ) {
        assert( location );

        ast::TraitDecl const * decl = symtab.lookupTrait( type->name );
        if ( !decl ) {
                SemanticError( *location, "use of undeclared trait " + type->name );
        } else if ( decl->params.size() != type->params.size() ) {
                SemanticError( *location, "incorrect number of trait parameters: " );
        }
        auto mut = ast::mutate( type );

        // Just linking in the node.
        mut->base = decl;

        // Need to carry over the 'sized' status of each decl in the instance.
        for ( auto p : group_iterate( decl->params, type->params ) ) {
                ast::TypeExpr const * expr = std::get<1>(p).as<ast::TypeExpr>();
                if ( !expr ) {
                        SemanticError( std::get<1>(p).get(), "Expression parameters for trait instances are currently unsupported: " );
                }
                if ( auto inst = expr->type.as<ast::TypeInstType>() ) {
                        ast::ptr<ast::TypeDecl> const & formalDecl = std::get<0>(p);
                        if ( !formalDecl->sized ) {
                                continue;
                        }
                        // To do this modification we need to reach through a readonly
                        // pointer. The Pass doesn't quite work in that way, so we just
                        // ensure it mutates in-place so it should work out.
                        ast::TypeDecl const * base = inst->base.get();
                        assert( base->unique() );
                        ast::TypeDecl * mutBase = ast::mutate( base );
                        mutBase->sized = true;
                }
        }
        return mut;
}

void LinkTypesCore::previsit( ast::QualifiedType const * ) {
        visit_children = false;
}

void LinkTypesCore::postvisit( ast::QualifiedType const * type ) {
        // Linking only makes sense for the 'oldest ancestor' of the qualified type.
        type->parent->accept( *visitor );
}

ast::EnumDecl const * LinkTypesCore::postvisit( ast::EnumDecl const * decl ) {
        // After visiting enum members for self-referencing members,
        // we replace the enum base. Right now it only works for StructDecl.
        if ( decl->base ) {
                if ( auto base = decl->base.as<ast::TypeInstType>() ) {
                        if ( auto structDecl = symtab.lookupStruct( base->name ) ) {
                                auto mut = ast::mutate( decl );
                                mut->base = new ast::StructInstType( structDecl );
                                decl = mut;
                        }
                        // visit the base
                } else if ( auto ptr = decl->base.as<ast::PointerType>() ) {
                        if ( auto base = ptr->base.as<ast::TypeInstType>() ) {
                                if ( auto structDecl = symtab.lookupStruct( base->name ) ) {
                                        auto mut = ast::mutate( decl );
                                        mut->base = new ast::PointerType(
                                                new ast::StructInstType( structDecl ) );
                                        decl = mut;
                                }
                        }
                }
        }

        // This section is common with struct/union, except for the return value.
        if ( !decl->body ) {
                return decl;
        }

        ForwardEnumsType::iterator fwds = forwardEnums.find( decl->name );
        if ( fwds != forwardEnums.end() ) {
                for ( auto inst : fwds->second ) {
                        inst->base = decl;
                }
                forwardEnums.erase( fwds );
        }

        return decl;
}

template<typename AggrDecl>
AggrDecl const * LinkTypesCore::renameGenericParams( AggrDecl const * decl ) {
        GuardValue( inGeneric ) = !decl->params.empty();
        if ( !inGeneric ) {
                return decl;
        }
        auto mut = ast::mutate( decl );
        for ( ast::ptr<ast::TypeDecl> & typeDecl : mut->params ) {
                typeDecl.get_and_mutate()->name = "__" + typeDecl->name + "_generic_";
        }
        return mut;
}

ast::StructDecl const * LinkTypesCore::previsit( ast::StructDecl const * decl ) {
        enterNamespace();
        return renameGenericParams( decl );
}

void LinkTypesCore::postvisit( ast::StructDecl const * decl ) {
        if ( !decl->body ) {
                return;
        }

        ForwardStructsType::iterator fwds = forwardStructs.find( decl->name );
        if ( fwds != forwardStructs.end() ) {
                for ( auto inst : fwds->second ) {
                        inst->base = decl;
                }
                forwardStructs.erase( fwds );
        }
}

ast::UnionDecl const * LinkTypesCore::previsit( ast::UnionDecl const * decl ) {
        enterNamespace();
        return renameGenericParams( decl );
}

void LinkTypesCore::postvisit( ast::UnionDecl const * decl ) {
        if ( !decl->body ) {
                return;
        }

        ForwardUnionsType::iterator fwds = forwardUnions.find( decl->name );
        if ( fwds != forwardUnions.end() ) {
                for ( auto inst : fwds->second ) {
                        inst->base = decl;
                }
                forwardUnions.erase( fwds );
        }
}

ast::TraitDecl const * LinkTypesCore::postvisit( ast::TraitDecl const * decl ) {
        // There is some overlap with code from decayForallPointers,
        // perhaps reorganization or shared helper functions are called for.
        // Move assertions from type parameters into the body of the trait.
        auto mut = ast::mutate( decl );
        for ( ast::ptr<ast::TypeDecl> const & td : decl->params ) {
                auto expanded = expandAssertions( td->assertions );
                for ( auto declWithType : expanded ) {
                        mut->members.emplace_back( declWithType.release() );
                }
        }
        return mut;
}

} // namespace

void linkInstanceTypes( ast::TranslationUnit & translationUnit ) {
        ast::Pass<LinkTypesCore>::run( translationUnit );
}

} // namespace Validate

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