source: src/InitTweak/FixInit.cc@ f326f99

//
// 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.
//
// FixInit.h --
//
// Author           : Rob Schluntz
// Created On       : Wed Jan 13 16:29:30 2016
// Last Modified By : Rob Schluntz
// Last Modified On : Thu Mar 31 13:54:58 2016
// Update Count     : 30
//

#include <stack>
#include <list>
#include "RemoveInit.h"
#include "SynTree/Declaration.h"
#include "SynTree/Type.h"
#include "SynTree/Expression.h"
#include "SynTree/Statement.h"
#include "SynTree/Initializer.h"
#include "SynTree/Mutator.h"
#include "GenPoly/PolyMutator.h"

namespace InitTweak {
        namespace {
                const std::list<Label> noLabels;
                const std::list<Expression*> noDesignators;
        }

        class FixInit : public GenPoly::PolyMutator {
          public:
                static void fixInitializers( std::list< Declaration * > &translationUnit );

                virtual ObjectDecl * mutate( ObjectDecl *objDecl );

                virtual CompoundStmt * mutate( CompoundStmt * compoundStmt );
                virtual Statement * mutate( ReturnStmt * returnStmt );
                virtual Statement * mutate( BranchStmt * branchStmt );

          private:
                // stack of list of statements - used to differentiate scopes
                std::list< std::list< Statement * > > dtorStmts;
        };

        void fix( std::list< Declaration * > & translationUnit ) {
                FixInit::fixInitializers( translationUnit );
        }

        void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
                FixInit fixer;
                mutateAll( translationUnit, fixer );
        }

        ObjectDecl *FixInit::mutate( ObjectDecl *objDecl ) {
                if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
                        // a decision should have been made by the resolver, so ctor and init are not both non-NULL
                        assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
                        if ( Statement * ctor = ctorInit->get_ctor() ) {
                                if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
                                        // generate:
                                        // static bool __objName_uninitialized = true;
                                        // if (__objName_uninitialized) {
                                        //   __ctor(__objName);
                                        //   void dtor_atexit() {
                                        //     __dtor(__objName);
                                        //   }
                                        //   on_exit(dtorOnExit, &__objName);
                                        //   __objName_uninitialized = false;
                                        // }

                                        // generate first line
                                        BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
                                        SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
                                        ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
                                        isUninitializedVar->fixUniqueId();

                                        // void dtor_atexit(...) {...}
                                        FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + "_dtor_atexit", DeclarationNode::NoStorageClass, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
                                        dtorCaller->fixUniqueId();
                                        dtorCaller->get_statements()->get_kids().push_back( ctorInit->get_dtor() );

                                        // on_exit(dtor_atexit);
                                        UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
                                        callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );

                                        // __objName_uninitialized = false;
                                        UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
                                        setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
                                        setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );

                                        // generate body of if
                                        CompoundStmt * initStmts = new CompoundStmt( noLabels );
                                        std::list< Statement * > & body = initStmts->get_kids();
                                        body.push_back( ctor );
                                        body.push_back( new DeclStmt( noLabels, dtorCaller ) );
                                        body.push_back( new ExprStmt( noLabels, callAtexit ) );
                                        body.push_back( new ExprStmt( noLabels, setTrue ) );

                                        // put it all together
                                        IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
                                        stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
                                        stmtsToAddAfter.push_back( ifStmt );
                                } else {
                                        stmtsToAddAfter.push_back( ctor );
                                        dtorStmts.back().push_front( ctorInit->get_dtor() );
                                }
                                objDecl->set_init( NULL );
                                ctorInit->set_ctor( NULL );
                                ctorInit->set_dtor( NULL );  // xxx - only destruct when constructing? Probably not?
                        } else if ( Initializer * init = ctorInit->get_init() ) {
                                objDecl->set_init( init );
                                ctorInit->set_init( NULL );
                        } else {
                                // no constructor and no initializer, which is okay
                                objDecl->set_init( NULL );
                        }
                        delete ctorInit;
                }
                return objDecl;
        }

        template<typename Iterator, typename OutputIterator>
        void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
                for ( Iterator it = begin ; it != end ; ++it ) {
                        // remove if instrinsic destructor statement
                        // xxx - test user manually calling intrinsic functions - what happens?
                        if ( ExprStmt * exprStmt = dynamic_cast< ExprStmt * >( *it ) ) {
                                ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * >( exprStmt->get_expr() );
                                assert( appExpr );
                                VariableExpr * function = dynamic_cast< VariableExpr * >( appExpr->get_function() );
                                assert( function );
                                // check for Intrinsic only - don't want to remove all overridable dtors because autogenerated dtor
                                // will call all member dtors, and some members may have a user defined dtor.
                                if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
                                        // don't need to call intrinsic dtor, because it does nothing
                                } else {
                                        // non-intrinsic dtors must be called
                                        *out++ = (*it)->clone();
                                }
                        } else {
                                // could also be a compound statement with a loop, in the case of an array
                                *out++ = (*it)->clone();
                        }
                }
        }


        CompoundStmt * FixInit::mutate( CompoundStmt * compoundStmt ) {
                // mutate statements - this will also populate dtorStmts list.
                // don't want to dump all destructors when block is left,
                // just the destructors associated with variables defined in this block,
                // so push a new list to the top of the stack so that we can differentiate scopes
                dtorStmts.push_back( std::list<Statement *>() );

                compoundStmt = PolyMutator::mutate( compoundStmt );
                std::list< Statement * > & statements = compoundStmt->get_kids();

                insertDtors( dtorStmts.back().begin(), dtorStmts.back().end(), back_inserter( statements ) );

                deleteAll( dtorStmts.back() );
                dtorStmts.pop_back();
                return compoundStmt;
        }

        Statement * FixInit::mutate( ReturnStmt * returnStmt ) {
                for ( std::list< std::list< Statement * > >::reverse_iterator list = dtorStmts.rbegin(); list != dtorStmts.rend(); ++list ) {
                        insertDtors( list->begin(), list->end(), back_inserter( stmtsToAdd ) );
                }
                return returnStmt;
        }

        Statement * FixInit::mutate( BranchStmt * branchStmt ) {
                // TODO: adding to the end of a block isn't sufficient, since
                // return/break/goto should trigger destructor when block is left.
                switch( branchStmt->get_type() ) {
                        case BranchStmt::Continue:
                        case BranchStmt::Break:
                                insertDtors( dtorStmts.back().begin(), dtorStmts.back().end(), back_inserter( stmtsToAdd ) );
                                break;
                        case BranchStmt::Goto:
                                // xxx
                                // if goto leaves a block, generate dtors for every block it leaves
                                // if goto is in same block but earlier statement, destruct every object that was defined after the statement
                                break;
                        default:
                                assert( false );
                }
                return branchStmt;
        }


} // namespace InitTweak

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