source: src/SymTab/Autogen.h@ e0a653d

//
// 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 : Wed Jun 21 17:25:26 2017
// Update Count     : 14
//

#ifndef AUTOGEN_H
#define AUTOGEN_H

#include <cassert>                // for assert
#include <iterator>               // for back_insert_iterator, back_inserter
#include <list>                   // for list
#include <string>                 // for string, operator==

#include "Common/UniqueName.h"    // for UniqueName
#include "InitTweak/InitTweak.h"  // for InitExpander
#include "Parser/LinkageSpec.h"   // for C
#include "SynTree/Constant.h"     // for Constant
#include "SynTree/Declaration.h"  // for ObjectDecl, Declaration (ptr only)
#include "SynTree/Expression.h"   // for UntypedExpr, NameExpr, VariableExpr
#include "SynTree/Initializer.h"  // for SingleInit
#include "SynTree/Label.h"        // for Label, noLabels
#include "SynTree/Statement.h"    // for Statement (ptr only), CompoundStmt
#include "SynTree/Type.h"         // for Type, ArrayType, Type::Qualifiers

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;

        /// 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, bool addCast = false, 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, const std::string & fname, OutputIterator out, Type * type, bool addCast = false ) {
        // want to be able to generate assignment, ctor, and dtor generically,
        // so fname is either ?=?, ?{}, or ^?{}
        UntypedExpr *fExpr = new UntypedExpr( new NameExpr( fname ) );

        // do something special for unnamed members
        dstParam = new AddressExpr( dstParam );
        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();
                assert( type );
                Type * castType = type->clone();
                castType->get_qualifiers() -= Type::Qualifiers( Type::Const | Type::Volatile | Type::Restrict | Type::Atomic );
                castType->set_lvalue( true ); // xxx - might not need this
                dstParam = new CastExpr( dstParam, new PointerType( Type::Qualifiers(), castType ) );
        }
        fExpr->get_args().push_back( dstParam );

        Statement * listInit = srcParam.buildListInit( fExpr );

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

        *out++ = new ExprStmt( noLabels, 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, bool addCast = false, 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 ;

                Expression * begin, * end, * update, * cmp;
                if ( forward ) {
                        // generate: for ( int i = 0; i < N; ++i )
                        begin = new ConstantExpr( Constant::from_int( 0 ) );
                        end = array->get_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)->get_args().push_back( array->get_dimension()->clone() );
                        ((UntypedExpr*)begin)->get_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->get_args().push_back( new VariableExpr( index ) );
                cond->get_args().push_back( end );

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

                UntypedExpr *dstIndex = new UntypedExpr( new NameExpr( "?[?]" ) );
                dstIndex->get_args().push_back( dstParam );
                dstIndex->get_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->get_dimension()->clone() );

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

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

                *out++ = block;
        }

        template< typename OutputIterator >
        Statement * genCall( InitTweak::InitExpander &  srcParam, Expression * dstParam, const std::string & fname, OutputIterator out, Type * type, bool 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;

                bool addCast = (fname == "?{}" || fname == "^?{}") && ( !obj || ( obj && ! obj->get_bitfieldWidth() ) );
                std::list< Statement * > stmts;
                genCall( srcParam, dstParam, fname, back_inserter( stmts ), obj->get_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
#endif // AUTOGEN_H