source: src/InitTweak/InitTweak.cc @ 79970ed

#include <algorithm>
#include "InitTweak.h"
#include "SynTree/Visitor.h"
#include "SynTree/Statement.h"
#include "SynTree/Initializer.h"
#include "SynTree/Expression.h"
#include "SynTree/Attribute.h"
#include "GenPoly/GenPoly.h"

namespace InitTweak {
        namespace {
                class HasDesignations : public Visitor {
                public:
                        bool hasDesignations = false;
                        template<typename Init>
                        void handleInit( Init * init ) {
                                if ( ! init->get_designators().empty() ) hasDesignations = true;
                                else Visitor::visit( init );
                        }
                        virtual void visit( SingleInit * singleInit ) { handleInit( singleInit); }
                        virtual void visit( ListInit * listInit ) { handleInit( listInit); }
                };

                class InitFlattener : public Visitor {
                        public:
                        virtual void visit( SingleInit * singleInit );
                        virtual void visit( ListInit * listInit );
                        std::list< Expression * > argList;
                };

                void InitFlattener::visit( SingleInit * singleInit ) {
                        argList.push_back( singleInit->get_value()->clone() );
                }

                void InitFlattener::visit( ListInit * listInit ) {
                        // flatten nested list inits
                        std::list<Initializer*>::iterator it = listInit->begin();
                        for ( ; it != listInit->end(); ++it ) {
                                (*it)->accept( *this );
                        }
                }
        }

        std::list< Expression * > makeInitList( Initializer * init ) {
                InitFlattener flattener;
                maybeAccept( init, flattener );
                return flattener.argList;
        }

        bool isDesignated( Initializer * init ) {
                HasDesignations finder;
                maybeAccept( init, finder );
                return finder.hasDesignations;
        }

        class InitExpander::ExpanderImpl {
        public:
                virtual std::list< Expression * > next( std::list< Expression * > & indices ) = 0;
                virtual Statement * buildListInit( UntypedExpr * callExpr, std::list< Expression * > & indices ) = 0;
        };

        class InitImpl : public InitExpander::ExpanderImpl {
        public:
                InitImpl( Initializer * init ) : init( init ) {}

                virtual std::list< Expression * > next( std::list< Expression * > & indices ) {
                        // this is wrong, but just a placeholder for now
                        // if ( ! flattened ) flatten( indices );
                        // return ! inits.empty() ? makeInitList( inits.front() ) : std::list< Expression * >();
                        return makeInitList( init );
                }

                virtual Statement * buildListInit( UntypedExpr * callExpr, std::list< Expression * > & indices );
        private:
                Initializer * init;
        };

        class ExprImpl : public InitExpander::ExpanderImpl {
        public:
                ExprImpl( Expression * expr ) : arg( expr ) {}

                virtual std::list< Expression * > next( std::list< Expression * > & indices ) {
                        std::list< Expression * > ret;
                        Expression * expr = maybeClone( arg );
                        if ( expr ) {
                                for ( std::list< Expression * >::reverse_iterator it = indices.rbegin(); it != indices.rend(); ++it ) {
                                        // go through indices and layer on subscript exprs ?[?]
                                        ++it;
                                        UntypedExpr * subscriptExpr = new UntypedExpr( new NameExpr( "?[?]") );
                                        subscriptExpr->get_args().push_back( expr );
                                        subscriptExpr->get_args().push_back( (*it)->clone() );
                                        expr = subscriptExpr;
                                }
                                ret.push_back( expr );
                        }
                        return ret;
                }

                virtual Statement * buildListInit( UntypedExpr * callExpr, std::list< Expression * > & indices );
        private:
                Expression * arg;
        };

        InitExpander::InitExpander( Initializer * init ) : expander( new InitImpl( init ) ) {}

        InitExpander::InitExpander( Expression * expr ) : expander( new ExprImpl( expr ) ) {}

        std::list< Expression * > InitExpander::operator*() {
                return cur;
        }

        InitExpander & InitExpander::operator++() {
                cur = expander->next( indices );
                return *this;
        }

        // use array indices list to build switch statement
        void InitExpander::addArrayIndex( Expression * index, Expression * dimension ) {
                indices.push_back( index );
                indices.push_back( dimension );
        }

        void InitExpander::clearArrayIndices() {
                indices.clear();
        }

        namespace {
                /// given index i, dimension d, initializer init, and callExpr f, generates
                ///   if (i < d) f(..., init)
                ///   ++i;
                /// so that only elements within the range of the array are constructed
                template< typename OutIterator >
                void buildCallExpr( UntypedExpr * callExpr, Expression * index, Expression * dimension, Initializer * init, OutIterator out ) {
                        UntypedExpr * cond = new UntypedExpr( new NameExpr( "?<?") );
                        cond->get_args().push_back( index->clone() );
                        cond->get_args().push_back( dimension->clone() );

                        std::list< Expression * > args = makeInitList( init );
                        callExpr->get_args().splice( callExpr->get_args().end(), args );

                        *out++ = new IfStmt( noLabels, cond, new ExprStmt( noLabels, callExpr ), NULL );

                        UntypedExpr * increment = new UntypedExpr( new NameExpr( "++?" ) );
                        increment->get_args().push_back( new AddressExpr( index->clone() ) );
                        *out++ = new ExprStmt( noLabels, increment );
                }

                template< typename OutIterator >
                void build( UntypedExpr * callExpr, InitExpander::IndexList::iterator idx, InitExpander::IndexList::iterator idxEnd, Initializer * init, OutIterator out ) {
                        if ( idx == idxEnd ) return;
                        Expression * index = *idx++;
                        assert( idx != idxEnd );
                        Expression * dimension = *idx++;

                        // xxx - may want to eventually issue a warning here if we can detect
                        // that the number of elements exceeds to dimension of the array
                        if ( idx == idxEnd ) {
                                if ( ListInit * listInit = dynamic_cast< ListInit * >( init ) ) {
                                        for ( Initializer * init : *listInit ) {
                                                buildCallExpr( callExpr->clone(), index, dimension, init, out );
                                        }
                                } else {
                                        buildCallExpr( callExpr->clone(), index, dimension, init, out );
                                }
                        } else {
                                std::list< Statement * > branches;

                                unsigned long cond = 0;
                                ListInit * listInit = dynamic_cast< ListInit * >( init );
                                if ( ! listInit ) {
                                        // xxx - this shouldn't be an error, but need a way to
                                        // terminate without creating output, so should catch this error
                                        throw SemanticError( "unbalanced list initializers" );
                                }

                                static UniqueName targetLabel( "L__autogen__" );
                                Label switchLabel( targetLabel.newName(), 0, std::list< Attribute * >{ new Attribute("unused") } );
                                for ( Initializer * init : *listInit ) {
                                        Expression * condition;
                                        // check for designations
                                        // if ( init-> ) {
                                                condition = new ConstantExpr( Constant::from_ulong( cond ) );
                                                ++cond;
                                        // } else {
                                        //      condition = // ... take designation
                                        //      cond = // ... take designation+1
                                        // }
                                        std::list< Statement * > stmts;
                                        build( callExpr, idx, idxEnd, init, back_inserter( stmts ) );
                                        stmts.push_back( new BranchStmt( noLabels, switchLabel, BranchStmt::Break ) );
                                        CaseStmt * caseStmt = new CaseStmt( noLabels, condition, stmts );
                                        branches.push_back( caseStmt );
                                }
                                *out++ = new SwitchStmt( noLabels, index->clone(), branches );
                                *out++ = new NullStmt( std::list<Label>{ switchLabel } );
                        }
                }
        }

        // if array came with an initializer list: initialize each element
        // may have more initializers than elements in the array - need to check at each index that
        // we haven't exceeded size.
        // may have fewer initializers than elements in the array - need to default construct
        // remaining elements.
        // To accomplish this, generate switch statement, consuming all of expander's elements
        Statement * InitImpl::buildListInit( UntypedExpr * dst, std::list< Expression * > & indices ) {
                if ( ! init ) return NULL;
                CompoundStmt * block = new CompoundStmt( noLabels );
                build( dst, indices.begin(), indices.end(), init, back_inserter( block->get_kids() ) );
                if ( block->get_kids().empty() ) {
                        delete block;
                        return NULL;
                } else {
                        init = NULL; // init was consumed in creating the list init
                        return block;
                }
        }

        Statement * ExprImpl::buildListInit( UntypedExpr * dst, std::list< Expression * > & indices ) {
                return NULL;
        }

        Statement * InitExpander::buildListInit( UntypedExpr * dst ) {
                return expander->buildListInit( dst, indices );
        }

        bool tryConstruct( ObjectDecl * objDecl ) {
                return ! LinkageSpec::isBuiltin( objDecl->get_linkage() ) &&
                        (objDecl->get_init() == NULL ||
                                ( objDecl->get_init() != NULL && objDecl->get_init()->get_maybeConstructed() )) &&
                        ! isDesignated( objDecl->get_init() )
                        && objDecl->get_storageClass() != DeclarationNode::Extern;
        }

        class CallFinder : public Visitor {
        public:
                typedef Visitor Parent;
                CallFinder( const std::list< std::string > & names ) : names( names ) {}

                virtual void visit( ApplicationExpr * appExpr ) {
                        handleCallExpr( appExpr );
                }

                virtual void visit( UntypedExpr * untypedExpr ) {
                        handleCallExpr( untypedExpr );
                }

                std::list< Expression * > * matches;
        private:
                const std::list< std::string > names;

                template< typename CallExpr >
                void handleCallExpr( CallExpr * expr ) {
                        Parent::visit( expr );
                        std::string fname = getFunctionName( expr );
                        if ( std::find( names.begin(), names.end(), fname ) != names.end() ) {
                                matches->push_back( expr );
                        }
                }
        };

        void collectCtorDtorCalls( Statement * stmt, std::list< Expression * > & matches ) {
                static CallFinder finder( std::list< std::string >{ "?{}", "^?{}" } );
                finder.matches = &matches;
                maybeAccept( stmt, finder );
        }

        Expression * getCtorDtorCall( Statement * stmt ) {
                std::list< Expression * > matches;
                collectCtorDtorCalls( stmt, matches );
                assert( matches.size() <= 1 );
                return matches.size() == 1 ? matches.front() : NULL;
        }

        namespace {
                VariableExpr * getCalledFunction( ApplicationExpr * appExpr ) {
                        assert( appExpr );
                        // xxx - it's possible this can be other things, e.g. MemberExpr, so this is insufficient
                        return dynamic_cast< VariableExpr * >( appExpr->get_function() );
                }
        }

        ApplicationExpr * isIntrinsicCallExpr( Expression * expr ) {
                ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * >( expr );
                if ( ! appExpr ) return NULL;
                VariableExpr * function = getCalledFunction( appExpr );
                assert( function );
                // check for Intrinsic only - don't want to remove all overridable ctor/dtors because autogenerated ctor/dtor
                // will call all member dtors, and some members may have a user defined dtor.
                return function->get_var()->get_linkage() == LinkageSpec::Intrinsic ? appExpr : NULL;
        }

        namespace {
                template <typename Predicate>
                bool allofCtorDtor( Statement * stmt, const Predicate & pred ) {
                        std::list< Expression * > callExprs;
                        collectCtorDtorCalls( stmt, callExprs );
                        // if ( callExprs.empty() ) return false; // xxx - do I still need this check?
                        return std::all_of( callExprs.begin(), callExprs.end(), pred);
                }
        }

        bool isIntrinsicSingleArgCallStmt( Statement * stmt ) {
                return allofCtorDtor( stmt, []( Expression * callExpr ){
                        if ( ApplicationExpr * appExpr = isIntrinsicCallExpr( callExpr ) ) {
                                assert( ! appExpr->get_function()->get_results().empty() );
                                FunctionType *funcType = GenPoly::getFunctionType( appExpr->get_function()->get_results().front() );
                                assert( funcType );
                                return funcType->get_parameters().size() == 1;
                        }
                        return false;
                });
        }

        bool isIntrinsicCallStmt( Statement * stmt ) {
                return allofCtorDtor( stmt, []( Expression * callExpr ) {
                        return isIntrinsicCallExpr( callExpr );
                });
        }

        namespace {
                template<typename CallExpr>
                Expression *& callArg( CallExpr * callExpr, unsigned int pos ) {
                        if ( pos >= callExpr->get_args().size() ) assert( false && "asking for argument that doesn't exist. Return NULL/throw exception?" );
                        for ( Expression *& arg : callExpr->get_args() ) {
                                if ( pos == 0 ) return arg;
                                pos--;
                        }
                        assert( false );
                }
        }

        Expression *& getCallArg( Expression * callExpr, unsigned int pos ) {
                if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * >( callExpr ) ) {
                        return callArg( appExpr, pos );
                } else if ( UntypedExpr * untypedExpr = dynamic_cast< UntypedExpr * >( callExpr ) ) {
                        return callArg( untypedExpr, pos );
                } else {
                        assert( false && "Unexpected expression type passed to getCallArg" );
                }
        }

        namespace {
                std::string funcName( Expression * func ) {
                        if ( NameExpr * nameExpr = dynamic_cast< NameExpr * >( func ) ) {
                                return nameExpr->get_name();
                        } else if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( func ) ) {
                                return varExpr->get_var()->get_name();
                        }       else if ( CastExpr * castExpr = dynamic_cast< CastExpr * >( func ) ) {
                                return funcName( castExpr->get_arg() );
                        } else {
                                assert( false && "Unexpected expression type being called as a function in call expression" );
                        }
                }
        }

        std::string getFunctionName( Expression * expr ) {
                if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * >( expr ) ) {
                        return funcName( appExpr->get_function() );
                } else if ( UntypedExpr * untypedExpr = dynamic_cast< UntypedExpr * > ( expr ) ) {
                        return funcName( untypedExpr->get_function() );
                } else {
                        std::cerr << expr << std::endl;
                        assert( false && "Unexpected expression type passed to getFunctionName" );
                }
        }

        Type * getPointerBase( Type * type ) {
                if ( PointerType * ptrType = dynamic_cast< PointerType * >( type ) ) {
                        return ptrType->get_base();
                } else if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
                        return arrayType->get_base();
                } else {
                        return NULL;
                }
        }

        Type * isPointerType( Type * type ) {
                if ( getPointerBase( type ) ) return type;
                else return NULL;
        }

        class ConstExprChecker : public Visitor {
        public:
                ConstExprChecker() : isConstExpr( true ) {}

                virtual void visit( ApplicationExpr *applicationExpr ) { isConstExpr = false; }
                virtual void visit( UntypedExpr *untypedExpr ) { isConstExpr = false; }
                virtual void visit( NameExpr *nameExpr ) { isConstExpr = false; }
                virtual void visit( CastExpr *castExpr ) { isConstExpr = false; }
                virtual void visit( LabelAddressExpr *labAddressExpr ) { isConstExpr = false; }
                virtual void visit( UntypedMemberExpr *memberExpr ) { isConstExpr = false; }
                virtual void visit( MemberExpr *memberExpr ) { isConstExpr = false; }
                virtual void visit( VariableExpr *variableExpr ) { isConstExpr = false; }
                virtual void visit( ConstantExpr *constantExpr ) { /* bottom out */ }
                // these might be okay?
                // virtual void visit( SizeofExpr *sizeofExpr );
                // virtual void visit( AlignofExpr *alignofExpr );
                // virtual void visit( UntypedOffsetofExpr *offsetofExpr );
                // virtual void visit( OffsetofExpr *offsetofExpr );
                // virtual void visit( OffsetPackExpr *offsetPackExpr );
                // virtual void visit( AttrExpr *attrExpr );
                // virtual void visit( CommaExpr *commaExpr );
                // virtual void visit( LogicalExpr *logicalExpr );
                // virtual void visit( ConditionalExpr *conditionalExpr );
                virtual void visit( TupleExpr *tupleExpr ) { isConstExpr = false; }
                virtual void visit( SolvedTupleExpr *tupleExpr ) { isConstExpr = false; }
                virtual void visit( TypeExpr *typeExpr ) { isConstExpr = false; }
                virtual void visit( AsmExpr *asmExpr ) { isConstExpr = false; }
                virtual void visit( UntypedValofExpr *valofExpr ) { isConstExpr = false; }
                virtual void visit( CompoundLiteralExpr *compLitExpr ) { isConstExpr = false; }

                bool isConstExpr;
        };

        bool isConstExpr( Expression * expr ) {
                if ( expr ) {
                        ConstExprChecker checker;
                        expr->accept( checker );
                        return checker.isConstExpr;
                }
                return true;
        }

        bool isConstExpr( Initializer * init ) {
                if ( init ) {
                        ConstExprChecker checker;
                        init->accept( checker );
                        return checker.isConstExpr;
                } // if
                // for all intents and purposes, no initializer means const expr
                return true;
        }

        bool isConstructor( const std::string & str ) { return str == "?{}"; }
        bool isDestructor( const std::string & str ) { return str == "^?{}"; }
        bool isCtorDtor( const std::string & str ) { return isConstructor( str ) || isDestructor( str ); }
}