source: src/InitTweak/FixGlobalInit.cc @ aea7168

//
// 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 : Peter A. Buhr
// Last Modified On : Wed Jun 29 22:33:15 2016
// Update Count     : 4
//

#include "FixGlobalInit.h"
#include "InitTweak.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 "SynTree/Attribute.h"
#include <algorithm>

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

        class GlobalFixer : public Visitor {
          public:
                GlobalFixer( const std::string & name, bool inLibrary );

                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;
                FunctionDecl * initFunction;
                FunctionDecl * destroyFunction;
        };

        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;
                } // if
                // for all intents and purposes, no initializer means const expr
                return true;
        }

        void fixGlobalInit( std::list< Declaration * > & translationUnit, const std::string & name, bool inLibrary ) {
                GlobalFixer fixer( name, inLibrary );
                acceptAll( translationUnit, fixer );
                // don't need to include function if it's empty
                if ( fixer.initFunction->get_statements()->get_kids().empty() ) {
                        delete fixer.initFunction;
                } else {
                        translationUnit.push_back( fixer.initFunction );
                } // if

                if ( fixer.destroyFunction->get_statements()->get_kids().empty() ) {
                        delete fixer.destroyFunction;
                } else {
                        translationUnit.push_back( fixer.destroyFunction );
                } // if
        }

  std::string globalFunctionName( 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 ret;
  }

        GlobalFixer::GlobalFixer( const std::string & name, bool inLibrary ) : tempNamer( "_global_init" ) {
                std::string fixedName = globalFunctionName( name );
                std::list< Expression * > ctorParameters;
                std::list< Expression * > dtorParameters;
                if ( inLibrary ) {
                        // Constructor/destructor attributes take a single parameter which
                        // is the priority, with lower numbers meaning higher priority.
                        // Functions specified with priority are guaranteed to run before
                        // functions without a priority. To ensure that constructors and destructors
                        // for library code are run before constructors and destructors for user code,
                        // specify a priority when building the library. Priorities 0-100 are reserved by gcc.
                        ctorParameters.push_back( new ConstantExpr( Constant::from_int( 101 ) ) );
                        dtorParameters.push_back( new ConstantExpr( Constant::from_int( 101 ) ) );
                }
                initFunction = new FunctionDecl( "_init_" + fixedName, DeclarationNode::Static, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
                initFunction->get_attributes().push_back( new Attribute( "constructor", ctorParameters ) );
                destroyFunction = new FunctionDecl( "_destroy_" + fixedName, DeclarationNode::Static, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
                destroyFunction->get_attributes().push_back( new Attribute( "destructor", dtorParameters ) );
        }

        void GlobalFixer::visit( ObjectDecl *objDecl ) {
                std::list< Statement * > & initStatements = initFunction->get_statements()->get_kids();
                std::list< Statement * > & destroyStatements = destroyFunction->get_statements()->get_kids();

                if ( ! tryConstruct( objDecl ) ) return; // don't construct @= or designated objects
                if ( objDecl->get_storageClass() == DeclarationNode::Extern ) return;
                // 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;

                if ( dynamic_cast< ArrayType * > ( objDecl->get_type() ) ) {
                        // xxx - initialize each element of the array
                } else {
                        // 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 );
                        initStatements.push_back( new DeclStmt( noLabels, newObj ) );

                        // 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 ) );
                        initStatements.push_back( new ImplicitCtorDtorStmt( new ExprStmt( noLabels, init ) ) );

                        // add destructor calls to global destroy function
                        UntypedExpr * destroy = new UntypedExpr( new NameExpr( "^?{}" ) );
                        destroy->get_args().push_back( new AddressExpr( new VariableExpr( objDecl ) ) );
                        destroyStatements.push_front( new ImplicitCtorDtorStmt( new ExprStmt( noLabels, destroy ) ) );
                } // if
        }

        // 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: //