source: src/AST/Pass.impl.hpp @ 712348a

//
// Cforall Version 1.0.0 Copyright (C) 2019 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Pass.impl.hpp --
//
// Author           : Thierry Delisle
// Created On       : Thu May 09 15::37::05 2019
// Last Modified By :
// Last Modified On :
// Update Count     :
//

#pragma once
// IWYU pragma: private, include "AST/Pass.hpp"

#define VISIT_START( node ) \
        using namespace ast; \
        /* back-up the visit children */ \
        __attribute__((unused)) ast::__pass::visit_children_guard guard1( ast::__pass::visit_children(pass, 0) ); \
        /* setup the scope for passes that want to run code at exit */ \
        __attribute__((unused)) ast::__pass::guard_value          guard2( ast::__pass::at_cleanup    (pass, 0) ); \
        /* call the implementation of the previsit of this pass */ \
        __pass::previsit( pass, node, 0 );

#define VISIT( code ) \
        /* if this node should visit its children */ \
        if ( __visit_children() ) { \
                /* visit the children */ \
                code \
        }

#define VISIT_END( type, node ) \
        /* call the implementation of the postvisit of this pass */ \
        auto __return = __pass::postvisit< type * >( node ); \
        assertf(__return, "post visit should never return null"); \
        return __return;

#ifdef PEDANTIC_PASS_ASSERT
#define __pedantic_pass_assert (...) assert (__VAR_ARGS__)
#define __pedantic_pass_assertf(...) assertf(__VAR_ARGS__)
#else
#define __pedantic_pass_assert (...)
#define __pedantic_pass_assertf(...)
#endif

namespace ast {
        namespace __pass {
                // Check if this is either a null pointer or a pointer to an empty container
                template<typename T>
                static inline bool empty( T * ptr ) {
                        return !ptr || ptr->empty();
                }

                template<typename it_t, template <class> class container_t>
                static inline void take_all( it_t it, container_t<ast::ptr<ast::Declaration>> * decls, bool * mutated = nullptr ) {
                        if(empty(decls)) return;

                        std::transform(decls->begin(), decls->end(), it, [](Declaration * decl) -> auto {
                                        return new DeclStmt( decl );
                                });
                        decls->clear();
                        if(mutated) *mutated = true;
                }

                template<typename it_t, template <class> class container_t>
                static inline void take_all( it_t it, container_t<ast::ptr<ast::Statement>> * decls, bool * mutated = nullptr ) {
                        if(empty(decls)) return;

                        std::move(decls->begin(), decls->end(), it);
                        decls->clear();
                        if(mutated) *mutated = true;
                }

                template<typename node_t>
                bool differs( const node_t * old_val, const node_t * new_val ) {
                        return old_val != new_val;
                }

                template< template <class> class container_t >
                bool differs( const container_t<ast::ptr< ast::Statement >> &, const container_t<ast::ptr< ast::Statement >> & new_val ) {
                        return !new_val.empty();
                }
        }

        template<typename parent_t, typename child_t>
        template< typename pass_t >
        void Pass< pass_t >::maybe_accept(
                const parent_t * & parent,
                const typename parent_t::child_t * child
        ) {
                const auto & old_val = parent->*child;
                if(!old_val) return;

                auto new_val = call_accept(old_val);

                if( __pass::differs(old_val, new_val) ) {
                        auto new_parent = mutate(parent);
                        new_parent->*child = new_val;
                        parent = new_parent;
                }
        }

        template< typename pass_t >
        template< typename node_t >
        auto Pass< pass_t >::call_accept( const node_t * node ) {
                __pedantic_pass_assert( __visit_children() );
                __pedantic_pass_assert( expr );

                return node->accept( *this );
        }

        template< typename pass_t >
        ast::Expr * Pass< pass_t >::call_accept( const ast::Expr * expr ) {
                __pedantic_pass_assert( __visit_children() );
                __pedantic_pass_assert( expr );

                const ast::TypeSubstitution ** env_ptr = __pass::env( pass, 0);
                if ( env_ptr && expr->env ) {
                        *env_ptr = expr->env;
                }

                return expr->accept( *this );
        }

        template< typename pass_t >
        Stmt * Pass< pass_t >::call_accept( const Stmt * stmt ) {
                __pedantic_pass_assert( __visit_children() );
                __pedantic_pass_assert( stmt );

                // add a few useful symbols to the scope
                using __pass::empty;

                // get the stmts/decls that will need to be spliced in
                auto stmts_before = __pass::stmtsToAddBefore( pass, 0);
                auto stmts_after  = __pass::stmtsToAddAfter ( pass, 0);
                auto decls_before = __pass::declsToAddBefore( pass, 0);
                auto decls_after  = __pass::declsToAddAfter ( pass, 0);

                // These may be modified by subnode but most be restored once we exit this statemnet.
                ValueGuardPtr< const ast::TypeSubstitution * > __old_env         ( __pass::env( pass, 0);  );
                ValueGuardPtr< typename std::remove_pointer< decltype(stmts_before) > __old_decls_before( stmts_before );
                ValueGuardPtr< typename std::remove_pointer< decltype(stmts_after ) > __old_decls_after ( stmts_after  );
                ValueGuardPtr< typename std::remove_pointer< decltype(decls_before) > __old_stmts_before( decls_before );
                ValueGuardPtr< typename std::remove_pointer< decltype(decls_after ) > __old_stmts_after ( decls_after  );

                // Now is the time to actually visit the node
                ast::Statement * nstmt = stmt->accept( *this );

                // If the pass doesn't want to add anything then we are done
                if( empty(stmts_before) && empty(stmts_after) && empty(decls_before) && empty(decls_after) ) {
                        return nstmt;
                }

                // Make sure that it is either adding statements or declartions but not both
                // this is because otherwise the order would be awkward to predict
                assert(( empty( stmts_before ) && empty( stmts_after ))
                    || ( empty( decls_before ) && empty( decls_after )) );

                // Create a new Compound Statement to hold the new decls/stmts
                ast::CompoundStmt * compound = new ast::CompoundStmt( parent->*child.location );

                // Take all the declarations that go before
                __pass::take_all( std::back_inserter( compound->kids ), decls_before );
                __pass::take_all( std::back_inserter( compound->kids ), stmts_before );

                // Insert the original declaration
                compound->kids.push_back( nstmt );

                // Insert all the declarations that go before
                __pass::take_all( std::back_inserter( compound->kids ), decls_after );
                __pass::take_all( std::back_inserter( compound->kids ), stmts_after );

                return compound;
        }

        template< typename pass_t >
        template< template <class> class container_t >
        container_t< ptr<Stmt> > Pass< pass_t >::call_accept( const container_t< ptr<Stmt> > & statements ) {
                __pedantic_pass_assert( __visit_children() );
                if( statements.empty() ) return {};

                // We are going to aggregate errors for all these statements
                SemanticErrorException errors;

                // add a few useful symbols to the scope
                using __pass::empty;

                // get the stmts/decls that will need to be spliced in
                auto stmts_before = __pass::stmtsToAddBefore( pass, 0);
                auto stmts_after  = __pass::stmtsToAddAfter ( pass, 0);
                auto decls_before = __pass::declsToAddBefore( pass, 0);
                auto decls_after  = __pass::declsToAddAfter ( pass, 0);

                // These may be modified by subnode but most be restored once we exit this statemnet.
                ValueGuardPtr< typename std::remove_pointer< decltype(stmts_before) > __old_decls_before( stmts_before );
                ValueGuardPtr< typename std::remove_pointer< decltype(stmts_after ) > __old_decls_after ( stmts_after  );
                ValueGuardPtr< typename std::remove_pointer< decltype(decls_before) > __old_stmts_before( decls_before );
                ValueGuardPtr< typename std::remove_pointer< decltype(decls_after ) > __old_stmts_after ( decls_after  );

                // update pass statitistics
                pass_visitor_stats.depth++;
                pass_visitor_stats.max->push(pass_visitor_stats.depth);
                pass_visitor_stats.avg->push(pass_visitor_stats.depth);

                bool mutated = false;
                container_t< ptr<Stmt> > new_kids;
                for( const Stmt * stmt : statements ) {
                        try {
                                __pedantic_pass_assert( stmt );
                                const ast::Statment * new_stmt = stmt->accept( visitor );
                                assert( new_stmt );
                                if(new_stmt != stmt ) mutated = true;

                                // Make sure that it is either adding statements or declartions but not both
                                // this is because otherwise the order would be awkward to predict
                                assert(( empty( stmts_before ) && empty( stmts_after ))
                                    || ( empty( decls_before ) && empty( decls_after )) );



                                // Take all the statements which should have gone after, N/A for first iteration
                                __pass::take_all( std::back_inserter( new_kids ), decls_before, &mutated );
                                __pass::take_all( std::back_inserter( new_kids ), stmts_before, &mutated );

                                // Now add the statement if there is one
                                new_kids.emplace_back( new_stmt );

                                // Take all the declarations that go before
                                __pass::take_all( std::back_inserter( new_kids ), decls_after, &mutated );
                                __pass::take_all( std::back_inserter( new_kids ), stmts_after, &mutated );
                        }
                        catch ( SemanticErrorException &e ) {
                                errors.append( e );
                        }
                }
                pass_visitor_stats.depth--;
                if ( !errors.isEmpty() ) { throw errors; }

                return mutated ? new_kids : {};
        }

        template< typename pass_t >
        template< template <class> class container_t, typename node_t >
        container_t< ast::ptr<node_t> > Pass< pass_t >::call_accept( const container_t< ast::ptr<node_t> > & container ) {
                __pedantic_pass_assert( __visit_children() );
                if( container.empty() ) return {};
                SemanticErrorException errors;

                pass_visitor_stats.depth++;
                pass_visitor_stats.max->push(pass_visitor_stats.depth);
                pass_visitor_stats.avg->push(pass_visitor_stats.depth);

                bool mutated = false;
                container_t< ast::ptr<node_t> > new_kids;
                for ( const node_t * node : container ) {
                        try {
                                __pedantic_pass_assert( node );
                                const node_t * new_node = strict_dynamic_cast< const node_t * >( node->accept( *this ) );
                                if(new_stmt != stmt ) mutated = true;

                                new_kids.emplace_back( new_stmt );
                        }
                        catch( SemanticErrorException &e ) {
                                errors.append( e );
                        }
                }
                pass_visitor_stats.depth--;
                if ( ! errors.isEmpty() ) { throw errors; }

                return mutated ? new_kids : {};
        }
}

//------------------------------------------------------------------------------------------------------------------------------------------------------------------------
//========================================================================================================================================================================
//========================================================================================================================================================================
//========================================================================================================================================================================
//========================================================================================================================================================================
//========================================================================================================================================================================
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------

template< typename pass_t >
inline void ast::acceptAll( std::list< ast::ptr<ast::Decl> > & decls, ast::Pass< pass_t > & visitor ) {
        // We are going to aggregate errors for all these statements
        SemanticErrorException errors;

        // add a few useful symbols to the scope
        using __pass::empty;

        // get the stmts/decls that will need to be spliced in
        auto decls_before = __pass::declsToAddBefore( pass, 0);
        auto decls_after  = __pass::declsToAddAfter ( pass, 0);

        // update pass statitistics
        pass_visitor_stats.depth++;
        pass_visitor_stats.max->push(pass_visitor_stats.depth);
        pass_visitor_stats.avg->push(pass_visitor_stats.depth);

        for ( std::list< ast::ptr<ast::Decl> >::iterator i = decls.begin(); ; ++i ) {
                // splice in new declarations after previous decl
                if ( !empty( decls_after ) ) { decls.splice( i, *decls_after ); }

                if ( i == decls.end() ) break;

                try {
                        // run visitor on declaration
                        ast::ptr<ast::Decl> & node = *i;
                        assert( node );
                        node = node->accept( visitor );
                }
                catch( SemanticErrorException &e ) {
                        errors.append( e );
                }

                // splice in new declarations before current decl
                if ( !empty( decls_before ) ) { decls.splice( i, *decls_before ); }
        }
        pass_visitor_stats.depth--;
        if ( !errors.isEmpty() ) { throw errors; }
}

// A NOTE ON THE ORDER OF TRAVERSAL
//
// Types and typedefs have their base types visited before they are added to the type table.  This is ok, since there is
// no such thing as a recursive type or typedef.
//
//             typedef struct { T *x; } T; // never allowed
//
// for structs/unions, it is possible to have recursion, so the decl should be added as if it's incomplete to begin, the
// members are traversed, and then the complete type should be added (assuming the type is completed by this particular
// declaration).
//
//             struct T { struct T *x; }; // allowed
//
// It is important to add the complete type to the symbol table *after* the members/base has been traversed, since that
// traversal may modify the definition of the type and these modifications should be visible when the symbol table is
// queried later in this pass.

//--------------------------------------------------------------------------
// ObjectDecl
template< typename pass_t >
ast::DeclWithType * ast::Pass< pass_t >::visit( const ast::ObjectDecl * node ) {
        VISIT_START( node );

        VISIT(
                {
                        indexer_guard guard { *this };
                        maybe_accept( node, ObjectDecl::type );
                }
                maybe_accept( node, ObjectDecl::init          );
                maybe_accept( node, ObjectDecl::bitfieldWidth );
                maybe_accept( node, ObjectDecl::attributes    );
        )

        __pass::indexer::AddId( pass, 0, node );

        VISIT_END( DeclWithType, node );
}

//--------------------------------------------------------------------------
// Attribute
template< typename pass_type >
ast::Attribute * ast::Pass< pass_type >::visit( const ast::Attribute * node  )  {
        VISIT_START(node);

        VISIT(
                maybe_accept( node, ast::Attribute::parameters );
        )

        VISIT_END(ast::Attribute *, node );
}

//--------------------------------------------------------------------------
// TypeSubstitution
template< typename pass_type >
TypeSubstitution * PassVisitor< pass_type >::mutate( const TypeSubstitution * node ) {
        MUTATE_START( node );

        #error this is broken

        for ( auto & p : node->typeEnv ) {
                indexerScopedMutate( p.second, *this );
        }
        for ( auto & p : node->varEnv ) {
                indexerScopedMutate( p.second, *this );
        }

        MUTATE_END( TypeSubstitution, node );
}

#undef VISIT_START
#undef VISIT
#undef VISIT_END