source: src/InitTweak/RemoveInit.cc@ 3cfe27f

//
// 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.
//
// RemoveInit.cc -- 
//
// Author           : Rob Schluntz
// Created On       : Mon May 18 07:44:20 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Tue Dec 15 15:37:26 2015
// Update Count     : 15
//

#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"

namespace InitTweak {
        namespace {
                const std::list<Label> noLabels;
        }
        
        class RemoveInit : public Mutator {
          public:
                RemoveInit();
                virtual ObjectDecl * mutate(ObjectDecl *objDecl);
                virtual DeclarationWithType * mutate( FunctionDecl *functionDecl );

                virtual Statement * mutate( ReturnStmt * returnStmt );
                
                virtual CompoundStmt * mutate(CompoundStmt * compoundStmt);
                
          protected:
                std::list< Statement* > stmtsToAddBefore;
                std::list< Statement* > stmtsToAddAfter;
                void mutateStatementList( std::list< Statement* > &statements );

                std::list<DeclarationWithType*> returnVals;
                UniqueName tempNamer;
                std::string funcName;
        };

        void tweak( std::list< Declaration * > translationUnit ) {
                RemoveInit remover;
                mutateAll( translationUnit, remover );
        }

        RemoveInit::RemoveInit() : tempNamer( "_retVal" ) {}
        
        void RemoveInit::mutateStatementList( std::list< Statement* > &statements ) {
                for ( std::list< Statement* >::iterator i = statements.begin(); i != statements.end(); ++i ) {
                        if ( ! stmtsToAddAfter.empty() ) {
                                statements.splice( i, stmtsToAddAfter );
                        } // if
                        *i = (*i)->acceptMutator( *this );
                        if ( ! stmtsToAddBefore.empty() ) {
                                statements.splice( i, stmtsToAddBefore );
                        } // if
                } // for
                if ( ! stmtsToAddAfter.empty() ) {
                        statements.splice( statements.end(), stmtsToAddAfter );
                } // if
        }

        CompoundStmt *RemoveInit::mutate(CompoundStmt *compoundStmt) {
                mutateStatementList( compoundStmt->get_kids() );
                return compoundStmt;
        }

        // in the case where an object has an initializer and a polymorphic type, insert an assignment immediately after the
        // declaration. This will (seemingly) cause the later phases to do the right thing with the assignment
        ObjectDecl *RemoveInit::mutate( ObjectDecl *objDecl ) {
                if (objDecl->get_init() && dynamic_cast<TypeInstType*>(objDecl->get_type())) {
                        if (SingleInit * single = dynamic_cast<SingleInit*>(objDecl->get_init())) {
                                UntypedExpr *assign = new UntypedExpr( new NameExpr( "?=?" ) );
                                assign->get_args().push_back( new AddressExpr (new NameExpr( objDecl->get_name() ) ) );
                                assign->get_args().push_back( single->get_value()->clone() );
                                stmtsToAddAfter.push_back(new ExprStmt(noLabels, assign));
                        } // if
                } // if
                return objDecl;
        }

        Statement *RemoveInit::mutate( ReturnStmt *returnStmt ) {
                // update for multiple return values
                assert( returnVals.size() == 0 || returnVals.size() == 1 );
                // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address
                // is being returned
                if ( returnStmt->get_expr() && returnVals.size() == 1 && funcName != "?=?" && ! returnVals.front()->get_type()->get_isLvalue()  ) {
                        ObjectDecl *newObj = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, returnVals.front()->get_type()->clone(), 0 );
                        stmtsToAddBefore.push_back( new DeclStmt( noLabels, newObj ) );
                        
                        UntypedExpr *assign = new UntypedExpr( new NameExpr( "?=?" ) );
                        assign->get_args().push_back( new AddressExpr (new NameExpr( newObj->get_name() ) ) );
                        assign->get_args().push_back( returnStmt->get_expr() );
                        stmtsToAddBefore.push_back(new ExprStmt(noLabels, assign));

                        returnStmt->set_expr( new VariableExpr( newObj ) );
                } // if
                return returnStmt;
        }

        DeclarationWithType* RemoveInit::mutate( FunctionDecl *functionDecl ) {
                std::list<DeclarationWithType*> oldReturnVals = returnVals;
                std::string oldFuncName = funcName;
                
                FunctionType * type = functionDecl->get_functionType();
                returnVals = type->get_returnVals();
                funcName = functionDecl->get_name();
                DeclarationWithType * decl = Mutator::mutate( functionDecl );
                returnVals = oldReturnVals;
                funcName = oldFuncName;
                return decl;
        }
} // namespace InitTweak

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