source: src/InitTweak/FixGlobalInit.cc @ 9a92216

//
// 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.
//
// FixGlobalInit.cc --
//
// Author           : Rob Schluntz
// Created On       : Mon May 04 15:14:56 2016
// Last Modified By : Rob Schluntz
// Last Modified On : Fri May 06 13:51:00 2016
// Update Count     : 2
//

#include "FixGlobalInit.h"
#include "SynTree/Declaration.h"
#include "SynTree/Type.h"
#include "SynTree/Expression.h"
#include "SynTree/Statement.h"
#include "SynTree/Initializer.h"
#include "SynTree/Visitor.h"
#include <algorithm>

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

        class GlobalFixer : public Visitor {
          public:
                GlobalFixer();

                virtual void visit( ObjectDecl *objDecl );
                virtual void visit( FunctionDecl *functionDecl );
                virtual void visit( StructDecl *aggregateDecl );
                virtual void visit( UnionDecl *aggregateDecl );
                virtual void visit( EnumDecl *aggregateDecl );
                virtual void visit( TraitDecl *aggregateDecl );
                virtual void visit( TypeDecl *typeDecl );

                UniqueName tempNamer;
                CompoundStmt * block;
        };

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

        void fixGlobalInit( std::list< Declaration * > & translationUnit, const std::string & name ) {
                GlobalFixer fixer;
                acceptAll( translationUnit, fixer );
                // attribute only appears on the forward declaration, so need to make two function decls:
                // one with the body, one with the attribute.
                FunctionDecl * initFunction = new FunctionDecl( initName( name ), DeclarationNode::NoStorageClass, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), 0, false, false );
                FunctionDecl * forward = initFunction->clone();
                forward->set_attribute( FunctionDecl::Constructor );
                initFunction->set_statements( fixer.block );
                translationUnit.push_back( forward );
                translationUnit.push_back( initFunction );
        }

  std::string initName( const std::string & name ) {
        // get basename
        std::string ret = name.substr( 0, name.find( '.' ) );
        // replace invalid characters with _
                static std::string invalid = "/-";
        replace_if( ret.begin(), ret.end(), []( char c ) { return invalid.find(c) != std::string::npos; }, '_' );
        return "_init_" + ret;
  }

        GlobalFixer::GlobalFixer() : tempNamer( "_global_init" ), block( new CompoundStmt( noLabels ) ) {
        }

        void GlobalFixer::visit( ObjectDecl *objDecl ) {
                std::list< Statement * > & statements = block->get_kids();

                if ( objDecl->get_init() == NULL ) return;
                if ( objDecl->get_type()->get_isConst() ) return; // temporary: can't assign to a const variable
                // C allows you to initialize objects with constant expressions
                // xxx - this is an optimization. Need to first resolve constructors before we decide
                // to keep C-style initializer.
                // if ( isConstExpr( objDecl->get_init() ) ) return;

                // steal initializer from object and attach it to a new temporary
                ObjectDecl *newObj = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, objDecl->get_type()->clone(), objDecl->get_init() );
                objDecl->set_init( NULL );
                statements.push_back( new DeclStmt( noLabels, newObj ) );

                // assign (later: copy construct) objDecl using temporary
                UntypedExpr * init = new UntypedExpr( new NameExpr( "?=?" ) );
                init->get_args().push_back( new AddressExpr( new VariableExpr( objDecl ) ) );
                init->get_args().push_back( new VariableExpr( newObj ) );
                statements.push_back( new ExprStmt( noLabels, init ) );

                // xxx- need to destruct objDecl atexit
        }

        // only modify global variables
        void GlobalFixer::visit( FunctionDecl *functionDecl ) {}
        void GlobalFixer::visit( StructDecl *aggregateDecl ) {}
        void GlobalFixer::visit( UnionDecl *aggregateDecl ) {}
        void GlobalFixer::visit( EnumDecl *aggregateDecl ) {}
        void GlobalFixer::visit( TraitDecl *aggregateDecl ) {}
        void GlobalFixer::visit( TypeDecl *typeDecl ) {}

} // namespace InitTweak

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