source: src/InitTweak/GenInit.cc @ 092528b

ADTaaron-thesisarm-ehast-experimentalcleanup-dtorsdeferred_resndemanglerenumforall-pointer-decayjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-exprnew-envno_listpersistent-indexerpthread-emulationqualifiedEnumresolv-newwith_gc
Last change on this file since 092528b was 092528b, checked in by Rob Schluntz <rschlunt@…>, 7 years ago

fix copy constructing/destructing qualified argument/return temporaries

  • Property mode set to 100644
File size: 15.3 KB
RevLine 
[51587aa]1//
2// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
[a0fdbd5]7// GenInit.cc --
[51587aa]8//
[cf16f94]9// Author           : Rob Schluntz
[51587aa]10// Created On       : Mon May 18 07:44:20 2015
[1e9d87b]11// Last Modified By : Rob Schluntz
[7b3f66b]12// Last Modified On : Fri May 13 11:37:48 2016
[d63eeb0]13// Update Count     : 166
[51587aa]14//
[a08ba92]15
[974906e2]16#include <stack>
17#include <list>
[a0fdbd5]18#include "GenInit.h"
[7b3f66b]19#include "InitTweak.h"
[42e2ad7]20#include "SynTree/Declaration.h"
21#include "SynTree/Type.h"
22#include "SynTree/Expression.h"
23#include "SynTree/Statement.h"
24#include "SynTree/Initializer.h"
25#include "SynTree/Mutator.h"
[620cb95]26#include "SymTab/Autogen.h"
[1ba88a0]27#include "SymTab/Mangler.h"
[1e9d87b]28#include "GenPoly/PolyMutator.h"
[5f98ce5]29#include "GenPoly/DeclMutator.h"
[1ba88a0]30#include "GenPoly/ScopedSet.h"
[65660bd]31#include "ResolvExpr/typeops.h"
[42e2ad7]32
33namespace InitTweak {
[a08ba92]34        namespace {
35                const std::list<Label> noLabels;
[5b40f30]36                const std::list<Expression *> noDesignators;
[a08ba92]37        }
[1e9d87b]38
[62e5546]39        class ReturnFixer final : public GenPoly::PolyMutator {
[cf16f94]40          public:
[a0fdbd5]41                /// consistently allocates a temporary variable for the return value
42                /// of a function so that anything which the resolver decides can be constructed
[02c7d04]43                /// into the return type of a function can be returned.
[a0fdbd5]44                static void makeReturnTemp( std::list< Declaration * > &translationUnit );
[02c7d04]45
[a0fdbd5]46                ReturnFixer();
[db4ecc5]47
[cce9429]48                typedef GenPoly::PolyMutator Parent;
49                using Parent::mutate;
[62e5546]50                virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
51                virtual Statement * mutate( ReturnStmt * returnStmt ) override;
[1e9d87b]52
53          protected:
[65660bd]54                FunctionType * ftype;
[cf16f94]55                std::string funcName;
56        };
[42e2ad7]57
[62e5546]58        class CtorDtor final : public GenPoly::PolyMutator {
[974906e2]59          public:
[1ba88a0]60                typedef GenPoly::PolyMutator Parent;
61                using Parent::mutate;
[02c7d04]62                /// create constructor and destructor statements for object declarations.
[5f98ce5]63                /// the actual call statements will be added in after the resolver has run
64                /// so that the initializer expression is only removed if a constructor is found
65                /// and the same destructor call is inserted in all of the appropriate locations.
[02c7d04]66                static void generateCtorDtor( std::list< Declaration * > &translationUnit );
[974906e2]67
[62e5546]68                virtual DeclarationWithType * mutate( ObjectDecl * ) override;
69                virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
[5f98ce5]70                // should not traverse into any of these declarations to find objects
71                // that need to be constructed or destructed
[62e5546]72                virtual Declaration* mutate( StructDecl *aggregateDecl ) override;
73                virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
74                virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
75                virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
76                virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
77                virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
[974906e2]78
[62e5546]79                virtual Type * mutate( FunctionType *funcType ) override { return funcType; }
[db4ecc5]80
[62e5546]81                virtual CompoundStmt * mutate( CompoundStmt * compoundStmt ) override;
[1ba88a0]82
83          private:
84                // set of mangled type names for which a constructor or destructor exists in the current scope.
85                // these types require a ConstructorInit node to be generated, anything else is a POD type and thus
86                // should not have a ConstructorInit generated.
87
88                bool isManaged( ObjectDecl * objDecl ) const ; // determine if object is managed
[65660bd]89                bool isManaged( Type * type ) const; // determine if type is managed
[1ba88a0]90                void handleDWT( DeclarationWithType * dwt ); // add type to managed if ctor/dtor
91                GenPoly::ScopedSet< std::string > managedTypes;
92                bool inFunction = false;
[974906e2]93        };
94
[62e5546]95        class HoistArrayDimension final : public GenPoly::DeclMutator {
[5f98ce5]96          public:
97                typedef GenPoly::DeclMutator Parent;
98
99                /// hoist dimension from array types in object declaration so that it uses a single
100                /// const variable of type size_t, so that side effecting array dimensions are only
101                /// computed once.
102                static void hoistArrayDimension( std::list< Declaration * > & translationUnit );
103
104          private:
[62e5546]105                using Parent::mutate;
106
107                virtual DeclarationWithType * mutate( ObjectDecl * objectDecl ) override;
108                virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
[5f98ce5]109                // should not traverse into any of these declarations to find objects
110                // that need to be constructed or destructed
[62e5546]111                virtual Declaration* mutate( StructDecl *aggregateDecl ) override { return aggregateDecl; }
112                virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
113                virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
114                virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
115                virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
116                virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
117
118                virtual Type* mutate( FunctionType *funcType ) override { return funcType; }
[5f98ce5]119
120                void hoist( Type * type );
121
122                DeclarationNode::StorageClass storageclass = DeclarationNode::NoStorageClass;
[40e636a]123                bool inFunction = false;
[5f98ce5]124        };
125
[a0fdbd5]126        void genInit( std::list< Declaration * > & translationUnit ) {
127                ReturnFixer::makeReturnTemp( translationUnit );
[5f98ce5]128                HoistArrayDimension::hoistArrayDimension( translationUnit );
[02c7d04]129                CtorDtor::generateCtorDtor( translationUnit );
130        }
131
[a0fdbd5]132        void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) {
133                ReturnFixer fixer;
134                mutateAll( translationUnit, fixer );
[a08ba92]135        }
[42e2ad7]136
[9facf3b]137        ReturnFixer::ReturnFixer() {}
[cf16f94]138
[a0fdbd5]139        Statement *ReturnFixer::mutate( ReturnStmt *returnStmt ) {
[65660bd]140                std::list< DeclarationWithType * > & returnVals = ftype->get_returnVals();
[cf16f94]141                assert( returnVals.size() == 0 || returnVals.size() == 1 );
142                // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address
143                // is being returned
[cce9429]144                // Note: under the assumption that assignments return *this, checking for ?=? here is an optimization, since it shouldn't be necessary to copy construct `this`. This is a temporary optimization until reference types are added, at which point this should be removed, along with the analogous optimization in copy constructor generation.
[7eabc25]145                if ( returnStmt->get_expr() && returnVals.size() == 1 && funcName != "?=?" && ! returnVals.front()->get_type()->get_isLvalue() ) {
[cce9429]146                        // explicitly construct the return value using the return expression and the retVal object
147                        assertf( returnVals.front()->get_name() != "", "Function %s has unnamed return value\n", funcName.c_str() );
[5b40f30]148                        UntypedExpr *construct = new UntypedExpr( new NameExpr( "?{}" ) );
[cce9429]149                        construct->get_args().push_back( new AddressExpr( new VariableExpr( returnVals.front() ) ) );
[5b40f30]150                        construct->get_args().push_back( returnStmt->get_expr() );
151                        stmtsToAdd.push_back(new ExprStmt(noLabels, construct));
[cf16f94]152
[cce9429]153                        // return the retVal object
154                        returnStmt->set_expr( new VariableExpr( returnVals.front() ) );
[cf16f94]155                } // if
156                return returnStmt;
157        }
158
[a0fdbd5]159        DeclarationWithType* ReturnFixer::mutate( FunctionDecl *functionDecl ) {
[65660bd]160                ValueGuard< FunctionType * > oldFtype( ftype );
[1ba88a0]161                ValueGuard< std::string > oldFuncName( funcName );
[1e9d87b]162
[65660bd]163                ftype = functionDecl->get_functionType();
[cf16f94]164                funcName = functionDecl->get_name();
[cce9429]165                return Parent::mutate( functionDecl );
[cf16f94]166        }
[974906e2]167
[4d2434a]168        // precompute array dimension expression, because constructor generation may duplicate it,
169        // which would be incorrect if it is a side-effecting computation.
[5f98ce5]170        void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
171                HoistArrayDimension hoister;
[40e636a]172                hoister.mutateDeclarationList( translationUnit );
[5f98ce5]173        }
174
175        DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
176                storageclass = objectDecl->get_storageClass();
177                DeclarationWithType * temp = Parent::mutate( objectDecl );
178                hoist( objectDecl->get_type() );
179                storageclass = DeclarationNode::NoStorageClass;
180                return temp;
181        }
182
183        void HoistArrayDimension::hoist( Type * type ) {
[40e636a]184                // if in function, generate const size_t var
[5f98ce5]185                static UniqueName dimensionName( "_array_dim" );
[40e636a]186
[f9cebb5]187                // C doesn't allow variable sized arrays at global scope or for static variables,
188                // so don't hoist dimension.
189                if ( ! inFunction ) return;
190                if ( storageclass == DeclarationNode::Static ) return;
191
192                if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
[5f98ce5]193                        if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
194
195                        // don't need to hoist dimension if it's a constexpr - only need to if there's potential
196                        // for side effects.
197                        if ( isConstExpr( arrayType->get_dimension() ) ) return;
198
199                        ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageclass, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
200                        arrayDimension->get_type()->set_isConst( true );
201
202                        arrayType->set_dimension( new VariableExpr( arrayDimension ) );
203                        addDeclaration( arrayDimension );
204
205                        hoist( arrayType->get_base() );
206                        return;
207                }
208        }
[974906e2]209
[40e636a]210        DeclarationWithType * HoistArrayDimension::mutate( FunctionDecl *functionDecl ) {
[1ba88a0]211                ValueGuard< bool > oldInFunc( inFunction );
[40e636a]212                inFunction = true;
213                DeclarationWithType * decl = Parent::mutate( functionDecl );
214                return decl;
215        }
216
[02c7d04]217        void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
218                CtorDtor ctordtor;
219                mutateAll( translationUnit, ctordtor );
[974906e2]220        }
221
[65660bd]222        bool CtorDtor::isManaged( Type * type ) const {
[ac9ca96]223                if ( TupleType * tupleType = dynamic_cast< TupleType * > ( type ) ) {
224                        // tuple is also managed if any of its components are managed
225                        if ( std::any_of( tupleType->get_types().begin(), tupleType->get_types().end(), [&](Type * type) { return isManaged( type ); }) ) {
226                                return true;
227                        }
228                }
[30b65d8]229                // a type is managed if it appears in the map of known managed types, or if it contains any polymorphism (is a type variable or generic type containing a type variable)
230                return managedTypes.find( SymTab::Mangler::mangle( type ) ) != managedTypes.end() || GenPoly::isPolyType( type );
[65660bd]231        }
232
[1ba88a0]233        bool CtorDtor::isManaged( ObjectDecl * objDecl ) const {
234                Type * type = objDecl->get_type();
235                while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
236                        type = at->get_base();
237                }
[65660bd]238                return isManaged( type );
[1ba88a0]239        }
240
241        void CtorDtor::handleDWT( DeclarationWithType * dwt ) {
242                // if this function is a user-defined constructor or destructor, mark down the type as "managed"
243                if ( ! LinkageSpec::isOverridable( dwt->get_linkage() ) && isCtorDtor( dwt->get_name() ) ) {
244                        std::list< DeclarationWithType * > & params = GenPoly::getFunctionType( dwt->get_type() )->get_parameters();
245                        assert( ! params.empty() );
246                        PointerType * type = safe_dynamic_cast< PointerType * >( params.front()->get_type() );
247                        managedTypes.insert( SymTab::Mangler::mangle( type->get_base() ) );
248                }
249        }
250
[092528b]251        ImplicitCtorDtorStmt * genCtorDtor( const std::string & fname, ObjectDecl * objDecl, Expression * arg ) {
252                // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
253                assertf( objDecl, "genCtorDtor passed null objDecl" );
254                std::list< Statement * > stmts;
255                InitExpander srcParam( maybeClone( arg ) );
256                SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), fname, back_inserter( stmts ), objDecl );
257                assert( stmts.size() <= 1 );
258                return stmts.size() == 1 ? safe_dynamic_cast< ImplicitCtorDtorStmt * >( stmts.front() ) : nullptr;
259        }
260
[f0121d7]261        ConstructorInit * genCtorInit( ObjectDecl * objDecl ) {
262                // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
263                // for each constructable object
264                std::list< Statement * > ctor;
265                std::list< Statement * > dtor;
266
267                InitExpander srcParam( objDecl->get_init() );
268                InitExpander nullParam( (Initializer *)NULL );
269                SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl );
270                SymTab::genImplicitCall( nullParam, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false );
271
272                // Currently genImplicitCall produces a single Statement - a CompoundStmt
273                // which  wraps everything that needs to happen. As such, it's technically
274                // possible to use a Statement ** in the above calls, but this is inherently
275                // unsafe, so instead we take the slightly less efficient route, but will be
276                // immediately informed if somehow the above assumption is broken. In this case,
277                // we could always wrap the list of statements at this point with a CompoundStmt,
278                // but it seems reasonable at the moment for this to be done by genImplicitCall
279                // itself. It is possible that genImplicitCall produces no statements (e.g. if
280                // an array type does not have a dimension). In this case, it's fine to ignore
281                // the object for the purposes of construction.
282                assert( ctor.size() == dtor.size() && ctor.size() <= 1 );
283                if ( ctor.size() == 1 ) {
284                        // need to remember init expression, in case no ctors exist
285                        // if ctor does exist, want to use ctor expression instead of init
286                        // push this decision to the resolver
287                        assert( dynamic_cast< ImplicitCtorDtorStmt * > ( ctor.front() ) && dynamic_cast< ImplicitCtorDtorStmt * > ( dtor.front() ) );
288                        return new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() );
289                }
290                return nullptr;
291        }
292
[db4ecc5]293        DeclarationWithType * CtorDtor::mutate( ObjectDecl * objDecl ) {
[1ba88a0]294                handleDWT( objDecl );
295                // hands off if @=, extern, builtin, etc.
296                // if global but initializer is not constexpr, always try to construct, since this is not legal C
297                if ( ( tryConstruct( objDecl ) && isManaged( objDecl ) ) || (! inFunction && ! isConstExpr( objDecl->get_init() ) ) ) {
298                        // constructed objects cannot be designated
299                        if ( isDesignated( objDecl->get_init() ) ) throw SemanticError( "Cannot include designations in the initializer for a managed Object. If this is really what you want, then initialize with @=.", objDecl );
[dcd73d1]300                        // constructed objects should not have initializers nested too deeply
301                        if ( ! checkInitDepth( objDecl ) ) throw SemanticError( "Managed object's initializer is too deep ", objDecl );
[1ba88a0]302
[f0121d7]303                        objDecl->set_init( genCtorInit( objDecl ) );
[974906e2]304                }
[1ba88a0]305                return Parent::mutate( objDecl );
[974906e2]306        }
307
[02c7d04]308        DeclarationWithType * CtorDtor::mutate( FunctionDecl *functionDecl ) {
[1ba88a0]309                ValueGuard< bool > oldInFunc = inFunction;
310                inFunction = true;
311
312                handleDWT( functionDecl );
313
314                managedTypes.beginScope();
315                // go through assertions and recursively add seen ctor/dtors
[8c49c0e]316                for ( auto & tyDecl : functionDecl->get_functionType()->get_forall() ) {
[1ba88a0]317                        for ( DeclarationWithType *& assertion : tyDecl->get_assertions() ) {
318                                assertion = assertion->acceptMutator( *this );
319                        }
320                }
[02c7d04]321                // parameters should not be constructed and destructed, so don't mutate FunctionType
322                mutateAll( functionDecl->get_oldDecls(), *this );
323                functionDecl->set_statements( maybeMutate( functionDecl->get_statements(), *this ) );
[1ba88a0]324
325                managedTypes.endScope();
[02c7d04]326                return functionDecl;
327        }
[1ba88a0]328
329        Declaration* CtorDtor::mutate( StructDecl *aggregateDecl ) {
330                // don't construct members, but need to take note if there is a managed member,
331                // because that means that this type is also managed
332                for ( Declaration * member : aggregateDecl->get_members() ) {
333                        if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
334                                if ( isManaged( field ) ) {
335                                        managedTypes.insert( SymTab::Mangler::mangle( aggregateDecl ) );
336                                        break;
337                                }
338                        }
339                }
340                return aggregateDecl;
341        }
342
343        CompoundStmt * CtorDtor::mutate( CompoundStmt * compoundStmt ) {
344                managedTypes.beginScope();
345                CompoundStmt * stmt = Parent::mutate( compoundStmt );
346                managedTypes.endScope();
347                return stmt;
348        }
349
[42e2ad7]350} // namespace InitTweak
351
[51587aa]352// Local Variables: //
353// tab-width: 4 //
354// mode: c++ //
355// compile-command: "make install" //
356// End: //
Note: See TracBrowser for help on using the repository browser.