source: src/SymTab/Autogen.h @ 6eed619

//
// 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 <string>                 // for string

#include "CodeGen/OperatorTable.h"
#include "Common/UniqueName.h"    // for UniqueName
#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 );

        /// size_t type - set when size_t typedef is seen. Useful in a few places,
        /// such as in determining array dimension type
        extern Type * SizeType;

        /// intrinsic dereference operator for unqualified types - set when *? function is seen in FindSpecialDeclarations.
        /// Useful for creating dereference ApplicationExprs without a full resolver pass.
        extern FunctionDecl * dereferenceOperator;

        // generate the type of an assignment function for paramType
        FunctionType * genAssignType( Type * paramType );

        // generate the type of a default constructor or destructor for paramType
        FunctionType * genDefaultType( Type * paramType );

        // generate the type of a copy constructor for paramType
        FunctionType * genCopyType( Type * paramType );

        /// 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 & srcParam, Expression * dstParam, const std::string & fname, OutputIterator out, Type * type, Type * addCast = nullptr, bool forward = true );

        /// 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 & 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;
        }

        /// 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 & 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;
        }

        template< typename OutputIterator >
        Statement * genCall( InitTweak::InitExpander & 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 );
                }
        }

        /// 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 & 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;
                }
        }
} // namespace SymTab

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