source: src/SymTab/Autogen.h@ 2890212

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Autogen.h --
//
// Author           : Rob Schluntz
// Created On       : Sun May 17 21:53:34 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Sat Jul 22 09:50:25 2017
// Update Count     : 15
//

#pragma once

#include <cassert>                // for assert
#include <iterator>               // for back_inserter
#include <string>                 // for string

#include "AST/Decl.hpp"
#include "AST/Eval.hpp"
#include "AST/Expr.hpp"
#include "AST/Init.hpp"
#include "AST/Node.hpp"
#include "AST/Stmt.hpp"
#include "AST/Type.hpp"
#include "CodeGen/OperatorTable.h"
#include "Common/UniqueName.h"    // for UniqueName
#include "Common/utility.h"       // for splice
#include "InitTweak/InitTweak.h"  // for InitExpander
#include "SynTree/Constant.h"     // for Constant
#include "SynTree/Declaration.h"  // for DeclarationWithType, ObjectDecl
#include "SynTree/Expression.h"   // for NameExpr, ConstantExpr, UntypedExpr...
#include "SynTree/Type.h"         // for Type, ArrayType, Type::Qualifiers

class CompoundStmt;
class Statement;

namespace SymTab {
        /// Generates assignment operators, constructors, and destructor for aggregate types as required
        void autogenerateRoutines( std::list< Declaration * > &translationUnit );

        /// returns true if obj's name is the empty string and it has a bitfield width
        bool isUnnamedBitfield( ObjectDecl * obj );
        bool isUnnamedBitfield( const ast::ObjectDecl * obj );

        /// generate the type of an assignment function for paramType.
        /// maybePolymorphic is true if the resulting FunctionType is allowed to be polymorphic
        FunctionType * genAssignType( Type * paramType, bool maybePolymorphic = true );

        /// generate the type of a default constructor or destructor for paramType.
        /// maybePolymorphic is true if the resulting FunctionType is allowed to be polymorphic
        FunctionType * genDefaultType( Type * paramType, bool maybePolymorphic = true );

        /// generate the type of a copy constructor for paramType.
        /// maybePolymorphic is true if the resulting FunctionType is allowed to be polymorphic
        FunctionType * genCopyType( Type * paramType, bool maybePolymorphic = true );

        /// Enum for loop direction
        enum LoopDirection { LoopBackward, LoopForward };

        /// inserts into out a generated call expression to function fname with arguments dstParam and srcParam. Intended to be used with generated ?=?, ?{}, and ^?{} calls.
        template< typename OutputIterator >
        Statement * genCall( InitTweak::InitExpander_old & srcParam, Expression * dstParam, const std::string & fname, OutputIterator out, Type * type, Type * addCast = nullptr, bool forward = true );

        template< typename OutIter >
        ast::ptr< ast::Stmt > genCall(
                InitTweak::InitExpander_new & srcParam, const ast::Expr * dstParam, 
                const CodeLocation & loc, const std::string & fname, OutIter && out, 
                const ast::Type * type, const ast::Type * addCast, LoopDirection forward = LoopForward );

        /// inserts into out a generated call expression to function fname with arguments dstParam and srcParam. Should only be called with non-array types.
        /// optionally returns a statement which must be inserted prior to the containing loop, if there is one
        template< typename OutputIterator >
        Statement * genScalarCall( InitTweak::InitExpander_old & srcParam, Expression * dstParam, std::string fname, OutputIterator out, Type * type, Type * addCast = nullptr ) {
                bool isReferenceCtorDtor = false;
                if ( dynamic_cast< ReferenceType * >( type ) && CodeGen::isCtorDtor( fname ) ) {
                        // reference constructors are essentially application of the rebind operator.
                        // apply & to both arguments, do not need a cast
                        fname = "?=?";
                        dstParam = new AddressExpr( dstParam );
                        addCast = nullptr;
                        isReferenceCtorDtor = true;
                }

                // want to be able to generate assignment, ctor, and dtor generically,
                // so fname is either ?=?, ?{}, or ^?{}
                UntypedExpr * fExpr = new UntypedExpr( new NameExpr( fname ) );

                if ( addCast ) {
                        // cast to T& with qualifiers removed, so that qualified objects can be constructed
                        // and destructed with the same functions as non-qualified objects.
                        // unfortunately, lvalue is considered a qualifier. For AddressExpr to resolve, its argument
                        // must have an lvalue qualified type, so remove all qualifiers except lvalue. If we ever
                        // remove lvalue as a qualifier, this can change to
                        //   type->get_qualifiers() = Type::Qualifiers();
                        Type * castType = addCast->clone();
                        castType->get_qualifiers() -= Type::Qualifiers( Type::Lvalue | Type::Const | Type::Volatile | Type::Restrict | Type::Atomic );
                        // castType->set_lvalue( true ); // xxx - might not need this
                        dstParam = new CastExpr( dstParam, new ReferenceType( Type::Qualifiers(), castType ) );
                }
                fExpr->args.push_back( dstParam );

                Statement * listInit = srcParam.buildListInit( fExpr );

                // fetch next set of arguments
                ++srcParam;

                // return if adding reference fails - will happen on default constructor and destructor
                if ( isReferenceCtorDtor && ! srcParam.addReference() ) {
                        delete fExpr;
                        return listInit;
                }

                std::list< Expression * > args = *srcParam;
                fExpr->args.splice( fExpr->args.end(), args );

                *out++ = new ExprStmt( fExpr );

                srcParam.clearArrayIndices();

                return listInit;
        }

        /// inserts into out a generated call expression to function fname with arguments dstParam and 
        /// srcParam. Should only be called with non-array types.
        /// optionally returns a statement which must be inserted prior to the containing loop, if 
        /// there is one
        template< typename OutIter >
        ast::ptr< ast::Stmt > genScalarCall( 
                InitTweak::InitExpander_new & srcParam, const ast::Expr * dstParam, 
                const CodeLocation & loc, std::string fname, OutIter && out, const ast::Type * type, 
                const ast::Type * addCast = nullptr
        ) {
                bool isReferenceCtorDtor = false;
                if ( dynamic_cast< const ast::ReferenceType * >( type ) && CodeGen::isCtorDtor( fname ) ) {
                        // reference constructors are essentially application of the rebind operator.
                        // apply & to both arguments, do not need a cast
                        fname = "?=?";
                        dstParam = new ast::AddressExpr{ dstParam };
                        addCast = nullptr;
                        isReferenceCtorDtor = true;
                }

                // want to be able to generate assignment, ctor, and dtor generically, so fname is one of
                // "?=?", "?{}", or "^?{}"
                ast::UntypedExpr * fExpr = new ast::UntypedExpr{ loc, new ast::NameExpr{ loc, fname } };

                if ( addCast ) {
                        // cast to T& with qualifiers removed, so that qualified objects can be constructed and 
                        // destructed with the same functions as non-qualified objects. Unfortunately, lvalue 
                        // is considered a qualifier - for AddressExpr to resolve, its argument must have an 
                        // lvalue-qualified type, so remove all qualifiers except lvalue.
                        // xxx -- old code actually removed lvalue too...
                        ast::ptr< ast::Type > guard = addCast;  // prevent castType from mutating addCast
                        ast::ptr< ast::Type > castType = addCast;
                        ast::remove_qualifiers( 
                                castType, 
                                ast::CV::Const | ast::CV::Volatile | ast::CV::Restrict | ast::CV::Atomic );
                        dstParam = new ast::CastExpr{ dstParam, new ast::ReferenceType{ castType } };
                }
                fExpr->args.emplace_back( dstParam );

                const ast::Stmt * listInit = srcParam.buildListInit( fExpr );

                // fetch next set of arguments
                ++srcParam;

                // return if adding reference fails -- will happen on default ctor and dtor
                if ( isReferenceCtorDtor && ! srcParam.addReference() ) return listInit;

                std::vector< ast::ptr< ast::Expr > > args = *srcParam;
                splice( fExpr->args, args );

                *out++ = new ast::ExprStmt{ loc, fExpr };

                srcParam.clearArrayIndices();
                
                return listInit;
        }

        /// Store in out a loop which calls fname on each element of the array with srcParam and dstParam as arguments.
        /// If forward is true, loop goes from 0 to N-1, else N-1 to 0
        template< typename OutputIterator >
        void genArrayCall( InitTweak::InitExpander_old & srcParam, Expression *dstParam, const std::string & fname, OutputIterator out, ArrayType *array, Type * addCast = nullptr, bool forward = true ) {
                static UniqueName indexName( "_index" );

                // for a flexible array member nothing is done -- user must define own assignment
                if ( ! array->get_dimension() ) return;

                if ( addCast ) {
                        // peel off array layer from cast
                        ArrayType * at = strict_dynamic_cast< ArrayType * >( addCast );
                        addCast = at->base;
                }

                Expression * begin, * end, * update, * cmp;
                if ( forward ) {
                        // generate: for ( int i = 0; i < N; ++i )
                        begin = new ConstantExpr( Constant::from_int( 0 ) );
                        end = array->dimension->clone();
                        cmp = new NameExpr( "?<?" );
                        update = new NameExpr( "++?" );
                } else {
                        // generate: for ( int i = N-1; i >= 0; --i )
                        begin = new UntypedExpr( new NameExpr( "?-?" ) );
                        ((UntypedExpr*)begin)->args.push_back( array->dimension->clone() );
                        ((UntypedExpr*)begin)->args.push_back( new ConstantExpr( Constant::from_int( 1 ) ) );
                        end = new ConstantExpr( Constant::from_int( 0 ) );
                        cmp = new NameExpr( "?>=?" );
                        update = new NameExpr( "--?" );
                }

                ObjectDecl *index = new ObjectDecl( indexName.newName(), Type::StorageClasses(), LinkageSpec::C, 0, new BasicType( Type::Qualifiers(), BasicType::SignedInt ), new SingleInit( begin ) );

                UntypedExpr *cond = new UntypedExpr( cmp );
                cond->args.push_back( new VariableExpr( index ) );
                cond->args.push_back( end );

                UntypedExpr *inc = new UntypedExpr( update );
                inc->args.push_back( new VariableExpr( index ) );

                UntypedExpr *dstIndex = new UntypedExpr( new NameExpr( "?[?]" ) );
                dstIndex->args.push_back( dstParam );
                dstIndex->args.push_back( new VariableExpr( index ) );
                dstParam = dstIndex;

                // srcParam must keep track of the array indices to build the
                // source parameter and/or array list initializer
                srcParam.addArrayIndex( new VariableExpr( index ), array->dimension->clone() );

                // for stmt's body, eventually containing call
                CompoundStmt * body = new CompoundStmt();
                Statement * listInit = genCall( srcParam, dstParam, fname, back_inserter( body->kids ), array->base, addCast, forward );

                // block containing for stmt and index variable
                std::list<Statement *> initList;
                CompoundStmt * block = new CompoundStmt();
                block->push_back( new DeclStmt( index ) );
                if ( listInit ) block->get_kids().push_back( listInit );
                block->push_back( new ForStmt( initList, cond, inc, body ) );

                *out++ = block;
        }

        /// Store in out a loop which calls fname on each element of the array with srcParam and 
        /// dstParam as arguments. If forward is true, loop goes from 0 to N-1, else N-1 to 0
        template< typename OutIter >
        void genArrayCall(
                InitTweak::InitExpander_new & srcParam, const ast::Expr * dstParam, 
                const CodeLocation & loc, const std::string & fname, OutIter && out, 
                const ast::ArrayType * array, const ast::Type * addCast = nullptr, 
                LoopDirection forward = LoopForward 
        ) {
                static UniqueName indexName( "_index" );

                // for a flexible array member nothing is done -- user must define own assignment
                if ( ! array->dimension ) return;

                if ( addCast ) {
                        // peel off array layer from cast
                        addCast = strict_dynamic_cast< const ast::ArrayType * >( addCast )->base;
                }

                ast::ptr< ast::Expr > begin, end;
                std::string cmp, update;

                if ( forward ) {
                        // generate: for ( int i = 0; i < N; ++i )
                        begin = ast::ConstantExpr::from_int( loc, 0 );
                        end = array->dimension;
                        cmp = "?<?";
                        update = "++?";
                } else {
                        // generate: for ( int i = N-1; i >= 0; --i )
                        begin = ast::call( 
                                loc, "?-?", array->dimension, ast::ConstantExpr::from_int( loc, 1 ) );
                        end = ast::ConstantExpr::from_int( loc, 0 );
                        cmp = "?>=?";
                        update = "--?";
                }

                ast::ptr< ast::DeclWithType > index = new ast::ObjectDecl{ 
                        loc, indexName.newName(), new ast::BasicType{ ast::BasicType::SignedInt }, 
                        new ast::SingleInit{ loc, begin } };
                ast::ptr< ast::Expr > indexVar = new ast::VariableExpr{ loc, index };
                
                ast::ptr< ast::Expr > cond = ast::call( loc, cmp, indexVar, end );
                
                ast::ptr< ast::Expr > inc = ast::call( loc, update, indexVar );
                
                ast::ptr< ast::Expr > dstIndex = ast::call( loc, "?[?]", dstParam, indexVar );
                
                // srcParam must keep track of the array indices to build the source parameter and/or 
                // array list initializer
                srcParam.addArrayIndex( indexVar, array->dimension );

                // for stmt's body, eventually containing call
                ast::CompoundStmt * body = new ast::CompoundStmt{ loc };
                ast::ptr< ast::Stmt > listInit = genCall( 
                        srcParam, dstIndex, loc, fname, std::back_inserter( body->kids ), array->base, addCast, 
                        forward );
                
                // block containing the stmt and index variable
                ast::CompoundStmt * block = new ast::CompoundStmt{ loc };
                block->push_back( new ast::DeclStmt{ loc, index } );
                if ( listInit ) { block->push_back( listInit ); }
                block->push_back( new ast::ForStmt{ loc, {}, cond, inc, body } );

                *out++ = block;
        }

        template< typename OutputIterator >
        Statement * genCall( InitTweak::InitExpander_old & srcParam, Expression * dstParam, const std::string & fname, OutputIterator out, Type * type, Type * addCast, bool forward ) {
                if ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
                        genArrayCall( srcParam, dstParam, fname, out, at, addCast, forward );
                        return 0;
                } else {
                        return genScalarCall( srcParam, dstParam, fname, out, type, addCast );
                }
        }

        template< typename OutIter >
        ast::ptr< ast::Stmt > genCall(
                InitTweak::InitExpander_new & srcParam, const ast::Expr * dstParam, 
                const CodeLocation & loc, const std::string & fname, OutIter && out, 
                const ast::Type * type, const ast::Type * addCast, LoopDirection forward
        ) {
                if ( auto at = dynamic_cast< const ast::ArrayType * >( type ) ) {
                        genArrayCall( 
                                srcParam, dstParam, loc, fname, std::forward< OutIter >(out), at, addCast, 
                                forward );
                        return {};
                } else {
                        return genScalarCall( 
                                srcParam, dstParam, loc, fname, std::forward< OutIter >( out ), type, addCast );
                }
        }

        /// inserts into out a generated call expression to function fname with arguments dstParam
        /// and srcParam. Intended to be used with generated ?=?, ?{}, and ^?{} calls. decl is the
        /// object being constructed. The function wraps constructor and destructor calls in an
        /// ImplicitCtorDtorStmt node.
        template< typename OutputIterator >
        void genImplicitCall( InitTweak::InitExpander_old & srcParam, Expression * dstParam, const std::string & fname, OutputIterator out, DeclarationWithType * decl, bool forward = true ) {
                ObjectDecl *obj = dynamic_cast<ObjectDecl *>( decl );
                assert( obj );
                // unnamed bit fields are not copied as they cannot be accessed
                if ( isUnnamedBitfield( obj ) ) return;

                Type * addCast = nullptr;
                if ( (fname == "?{}" || fname == "^?{}") && ( !obj || ( obj && ! obj->get_bitfieldWidth() ) ) ) {
                        assert( dstParam->result );
                        addCast = dstParam->result;
                }
                std::list< Statement * > stmts;
                genCall( srcParam, dstParam, fname, back_inserter( stmts ), obj->type, addCast, forward );

                // currently genCall should produce at most one element, but if that changes then the next line needs to be updated to grab the statement which contains the call
                assert( stmts.size() <= 1 );
                if ( stmts.size() == 1 ) {
                        Statement * callStmt = stmts.front();
                        if ( addCast ) {
                                // implicitly generated ctor/dtor calls should be wrapped
                                // so that later passes are aware they were generated.
                                // xxx - don't mark as an implicit ctor/dtor if obj is a bitfield,
                                // because this causes the address to be taken at codegen, which is illegal in C.
                                callStmt = new ImplicitCtorDtorStmt( callStmt );
                        }
                        *out++ = callStmt;
                }
        }

        static inline ast::ptr< ast::Stmt > genImplicitCall( 
                InitTweak::InitExpander_new & srcParam, const ast::Expr * dstParam, 
                const CodeLocation & loc, const std::string & fname, const ast::ObjectDecl * obj, 
                LoopDirection forward = LoopForward 
        ) {
                // unnamed bit fields are not copied as they cannot be accessed
                if ( isUnnamedBitfield( obj ) ) return {};

                ast::ptr< ast::Type > addCast;
                if ( (fname == "?{}" || fname == "^?{}") && ( ! obj || ( obj && ! obj->bitfieldWidth ) ) ) {
                        assert( dstParam->result );
                        addCast = dstParam->result;
                }

                std::vector< ast::ptr< ast::Stmt > > stmts;
                genCall( 
                        srcParam, dstParam, loc, fname, back_inserter( stmts ), obj->type, addCast, forward );

                if ( stmts.empty() ) {
                        return {};
                } else if ( stmts.size() == 1 ) {
                        const ast::Stmt * callStmt = stmts.front();
                        if ( addCast ) {
                                // implicitly generated ctor/dtor calls should be wrapped so that later passes are 
                                // aware they were generated.
                                callStmt = new ast::ImplicitCtorDtorStmt{ callStmt->location, callStmt };
                        }
                        return callStmt;
                } else {
                        assert( false );
                        return {};
                }
        }
} // namespace SymTab

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