source: src/InitTweak/GenInit.cc @ 21a1efb

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 21a1efb was 8135d4c, checked in by Rob Schluntz <rschlunt@…>, 7 years ago

Merge branch 'master' into references

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[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
[3a5131ed]11// Last Modified By : Peter A. Buhr
[615a096]12// Last Modified On : Fri Mar 17 09:12:36 2017
13// Update Count     : 183
[51587aa]14//
[8ca3a72]15#include "GenInit.h"
16
[d180746]17#include <stddef.h>                // for NULL
18#include <algorithm>               // for any_of
19#include <cassert>                 // for assert, safe_dynamic_cast, assertf
20#include <iterator>                // for back_inserter, inserter, back_inse...
21#include <list>                    // for _List_iterator, list
[8ca3a72]22
[8135d4c]23#include "CodeGen/OperatorTable.h"
[d180746]24#include "Common/PassVisitor.h"    // for PassVisitor, WithGuards, WithShort...
25#include "Common/SemanticError.h"  // for SemanticError
26#include "Common/UniqueName.h"     // for UniqueName
27#include "Common/utility.h"        // for ValueGuard, maybeClone
28#include "GenPoly/DeclMutator.h"   // for DeclMutator
29#include "GenPoly/GenPoly.h"       // for getFunctionType, isPolyType
30#include "GenPoly/ScopedSet.h"     // for ScopedSet, ScopedSet<>::const_iter...
31#include "InitTweak.h"             // for isConstExpr, InitExpander, checkIn...
32#include "Parser/LinkageSpec.h"    // for isOverridable, C
33#include "SymTab/Autogen.h"        // for genImplicitCall, SizeType
34#include "SymTab/Mangler.h"        // for Mangler
35#include "SynTree/Declaration.h"   // for ObjectDecl, DeclarationWithType
36#include "SynTree/Expression.h"    // for VariableExpr, UntypedExpr, Address...
37#include "SynTree/Initializer.h"   // for ConstructorInit, SingleInit, Initi...
38#include "SynTree/Label.h"         // for Label
39#include "SynTree/Mutator.h"       // for mutateAll
40#include "SynTree/Statement.h"     // for CompoundStmt, ImplicitCtorDtorStmt
41#include "SynTree/Type.h"          // for Type, ArrayType, Type::Qualifiers
42#include "SynTree/Visitor.h"       // for acceptAll, maybeAccept
[42e2ad7]43
44namespace InitTweak {
[a08ba92]45        namespace {
46                const std::list<Label> noLabels;
[5b40f30]47                const std::list<Expression *> noDesignators;
[a08ba92]48        }
[1e9d87b]49
[d24d4e1]50        struct ReturnFixer : public WithStmtsToAdd, public WithGuards {
[a0fdbd5]51                /// consistently allocates a temporary variable for the return value
52                /// of a function so that anything which the resolver decides can be constructed
[02c7d04]53                /// into the return type of a function can be returned.
[a0fdbd5]54                static void makeReturnTemp( std::list< Declaration * > &translationUnit );
[02c7d04]55
[7b6ca2e]56                void premutate( FunctionDecl *functionDecl );
57                void premutate( ReturnStmt * returnStmt );
[1e9d87b]58
59          protected:
[c6976ba]60                FunctionType * ftype = nullptr;
[cf16f94]61                std::string funcName;
62        };
[42e2ad7]63
[d24d4e1]64        struct CtorDtor : public WithGuards, public WithShortCircuiting  {
[02c7d04]65                /// create constructor and destructor statements for object declarations.
[5f98ce5]66                /// the actual call statements will be added in after the resolver has run
67                /// so that the initializer expression is only removed if a constructor is found
68                /// and the same destructor call is inserted in all of the appropriate locations.
[02c7d04]69                static void generateCtorDtor( std::list< Declaration * > &translationUnit );
[974906e2]70
[d24d4e1]71                void previsit( ObjectDecl * );
72                void previsit( FunctionDecl *functionDecl );
73
[5f98ce5]74                // should not traverse into any of these declarations to find objects
75                // that need to be constructed or destructed
[d24d4e1]76                void previsit( StructDecl *aggregateDecl );
[9ff56e7]77                void previsit( __attribute__((unused)) UnionDecl    * aggregateDecl ) { visit_children = false; }
78                void previsit( __attribute__((unused)) EnumDecl     * aggregateDecl ) { visit_children = false; }
79                void previsit( __attribute__((unused)) TraitDecl    * aggregateDecl ) { visit_children = false; }
80                void previsit( __attribute__((unused)) TypeDecl     * typeDecl )      { visit_children = false; }
81                void previsit( __attribute__((unused)) TypedefDecl  * typeDecl )      { visit_children = false; }
82                void previsit( __attribute__((unused)) FunctionType * funcType )      { visit_children = false; }
[db4ecc5]83
[d24d4e1]84                void previsit( CompoundStmt * compoundStmt );
[1ba88a0]85
86          private:
87                // set of mangled type names for which a constructor or destructor exists in the current scope.
88                // these types require a ConstructorInit node to be generated, anything else is a POD type and thus
89                // should not have a ConstructorInit generated.
90
91                bool isManaged( ObjectDecl * objDecl ) const ; // determine if object is managed
[65660bd]92                bool isManaged( Type * type ) const; // determine if type is managed
[1ba88a0]93                void handleDWT( DeclarationWithType * dwt ); // add type to managed if ctor/dtor
94                GenPoly::ScopedSet< std::string > managedTypes;
95                bool inFunction = false;
[974906e2]96        };
97
[62e5546]98        class HoistArrayDimension final : public GenPoly::DeclMutator {
[5f98ce5]99          public:
100                typedef GenPoly::DeclMutator Parent;
101
102                /// hoist dimension from array types in object declaration so that it uses a single
103                /// const variable of type size_t, so that side effecting array dimensions are only
104                /// computed once.
105                static void hoistArrayDimension( std::list< Declaration * > & translationUnit );
106
107          private:
[62e5546]108                using Parent::mutate;
109
110                virtual DeclarationWithType * mutate( ObjectDecl * objectDecl ) override;
111                virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ) override;
[5f98ce5]112                // should not traverse into any of these declarations to find objects
113                // that need to be constructed or destructed
[62e5546]114                virtual Declaration* mutate( StructDecl *aggregateDecl ) override { return aggregateDecl; }
115                virtual Declaration* mutate( UnionDecl *aggregateDecl ) override { return aggregateDecl; }
116                virtual Declaration* mutate( EnumDecl *aggregateDecl ) override { return aggregateDecl; }
117                virtual Declaration* mutate( TraitDecl *aggregateDecl ) override { return aggregateDecl; }
118                virtual TypeDecl* mutate( TypeDecl *typeDecl ) override { return typeDecl; }
119                virtual Declaration* mutate( TypedefDecl *typeDecl ) override { return typeDecl; }
120
121                virtual Type* mutate( FunctionType *funcType ) override { return funcType; }
[5f98ce5]122
123                void hoist( Type * type );
124
[68fe077a]125                Type::StorageClasses storageClasses;
[40e636a]126                bool inFunction = false;
[5f98ce5]127        };
128
[a0fdbd5]129        void genInit( std::list< Declaration * > & translationUnit ) {
130                ReturnFixer::makeReturnTemp( translationUnit );
[5f98ce5]131                HoistArrayDimension::hoistArrayDimension( translationUnit );
[02c7d04]132                CtorDtor::generateCtorDtor( translationUnit );
133        }
134
[a0fdbd5]135        void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) {
[7b6ca2e]136                PassVisitor<ReturnFixer> fixer;
[a0fdbd5]137                mutateAll( translationUnit, fixer );
[a08ba92]138        }
[42e2ad7]139
[7b6ca2e]140        void ReturnFixer::premutate( ReturnStmt *returnStmt ) {
[65660bd]141                std::list< DeclarationWithType * > & returnVals = ftype->get_returnVals();
[cf16f94]142                assert( returnVals.size() == 0 || returnVals.size() == 1 );
[c6976ba]143                // hands off if the function returns a reference - we don't want to allocate a temporary if a variable's address
[cf16f94]144                // is being returned
[c6976ba]145                if ( returnStmt->get_expr() && returnVals.size() == 1 && ! dynamic_cast< ReferenceType * >( returnVals.front()->get_type() ) ) {
[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() );
[c6976ba]148
149                        stmtsToAddBefore.push_back( genCtorDtor( "?{}", dynamic_cast< ObjectDecl *>( returnVals.front() ), returnStmt->get_expr() ) );
[cf16f94]150
[cce9429]151                        // return the retVal object
152                        returnStmt->set_expr( new VariableExpr( returnVals.front() ) );
[cf16f94]153                } // if
154        }
155
[7b6ca2e]156        void ReturnFixer::premutate( FunctionDecl *functionDecl ) {
[4eb31f2b]157                GuardValue( ftype );
158                GuardValue( funcName );
[1e9d87b]159
[65660bd]160                ftype = functionDecl->get_functionType();
[cf16f94]161                funcName = functionDecl->get_name();
162        }
[974906e2]163
[4d2434a]164        // precompute array dimension expression, because constructor generation may duplicate it,
165        // which would be incorrect if it is a side-effecting computation.
[5f98ce5]166        void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) {
167                HoistArrayDimension hoister;
[40e636a]168                hoister.mutateDeclarationList( translationUnit );
[5f98ce5]169        }
170
171        DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) {
[a7c90d4]172                storageClasses = objectDecl->get_storageClasses();
[5f98ce5]173                DeclarationWithType * temp = Parent::mutate( objectDecl );
174                hoist( objectDecl->get_type() );
175                return temp;
176        }
177
178        void HoistArrayDimension::hoist( Type * type ) {
[40e636a]179                // if in function, generate const size_t var
[5f98ce5]180                static UniqueName dimensionName( "_array_dim" );
[40e636a]181
[a7c90d4]182                // C doesn't allow variable sized arrays at global scope or for static variables, so don't hoist dimension.
[f9cebb5]183                if ( ! inFunction ) return;
[08d5507b]184                if ( storageClasses.is_static ) return;
[f9cebb5]185
186                if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
[5f98ce5]187                        if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist?
188
[a7c90d4]189                        // don't need to hoist dimension if it's a constexpr - only need to if there's potential for side effects.
[5f98ce5]190                        if ( isConstExpr( arrayType->get_dimension() ) ) return;
191
[a7c90d4]192                        ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageClasses, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) );
[615a096]193                        arrayDimension->get_type()->set_const( true );
[5f98ce5]194
195                        arrayType->set_dimension( new VariableExpr( arrayDimension ) );
196                        addDeclaration( arrayDimension );
197
198                        hoist( arrayType->get_base() );
199                        return;
200                }
201        }
[974906e2]202
[40e636a]203        DeclarationWithType * HoistArrayDimension::mutate( FunctionDecl *functionDecl ) {
[1ba88a0]204                ValueGuard< bool > oldInFunc( inFunction );
[40e636a]205                inFunction = true;
206                DeclarationWithType * decl = Parent::mutate( functionDecl );
207                return decl;
208        }
209
[02c7d04]210        void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) {
[d24d4e1]211                PassVisitor<CtorDtor> ctordtor;
212                acceptAll( translationUnit, ctordtor );
[974906e2]213        }
214
[65660bd]215        bool CtorDtor::isManaged( Type * type ) const {
[c6976ba]216                // at least for now, references are never constructed
217                if ( dynamic_cast< ReferenceType * >( type ) ) return false;
[0b465a5]218                // need to clear and reset qualifiers when determining if a type is managed
219                ValueGuard< Type::Qualifiers > qualifiers( type->get_qualifiers() );
220                type->get_qualifiers() = Type::Qualifiers();
[ac9ca96]221                if ( TupleType * tupleType = dynamic_cast< TupleType * > ( type ) ) {
222                        // tuple is also managed if any of its components are managed
223                        if ( std::any_of( tupleType->get_types().begin(), tupleType->get_types().end(), [&](Type * type) { return isManaged( type ); }) ) {
224                                return true;
225                        }
226                }
[30b65d8]227                // 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)
228                return managedTypes.find( SymTab::Mangler::mangle( type ) ) != managedTypes.end() || GenPoly::isPolyType( type );
[65660bd]229        }
230
[1ba88a0]231        bool CtorDtor::isManaged( ObjectDecl * objDecl ) const {
232                Type * type = objDecl->get_type();
233                while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
234                        type = at->get_base();
235                }
[65660bd]236                return isManaged( type );
[1ba88a0]237        }
238
239        void CtorDtor::handleDWT( DeclarationWithType * dwt ) {
240                // if this function is a user-defined constructor or destructor, mark down the type as "managed"
[bff227f]241                if ( ! LinkageSpec::isOverridable( dwt->get_linkage() ) && CodeGen::isCtorDtor( dwt->get_name() ) ) {
[1ba88a0]242                        std::list< DeclarationWithType * > & params = GenPoly::getFunctionType( dwt->get_type() )->get_parameters();
243                        assert( ! params.empty() );
[ce8c12f]244                        Type * type = InitTweak::getPointerBase( params.front()->get_type() );
245                        assert( type );
246                        managedTypes.insert( SymTab::Mangler::mangle( type ) );
[1ba88a0]247                }
248        }
249
[092528b]250        ImplicitCtorDtorStmt * genCtorDtor( const std::string & fname, ObjectDecl * objDecl, Expression * arg ) {
251                // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
252                assertf( objDecl, "genCtorDtor passed null objDecl" );
253                std::list< Statement * > stmts;
254                InitExpander srcParam( maybeClone( arg ) );
255                SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), fname, back_inserter( stmts ), objDecl );
256                assert( stmts.size() <= 1 );
257                return stmts.size() == 1 ? safe_dynamic_cast< ImplicitCtorDtorStmt * >( stmts.front() ) : nullptr;
258        }
259
[f0121d7]260        ConstructorInit * genCtorInit( ObjectDecl * objDecl ) {
261                // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor
262                // for each constructable object
263                std::list< Statement * > ctor;
264                std::list< Statement * > dtor;
265
266                InitExpander srcParam( objDecl->get_init() );
267                InitExpander nullParam( (Initializer *)NULL );
268                SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl );
269                SymTab::genImplicitCall( nullParam, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false );
270
271                // Currently genImplicitCall produces a single Statement - a CompoundStmt
272                // which  wraps everything that needs to happen. As such, it's technically
273                // possible to use a Statement ** in the above calls, but this is inherently
274                // unsafe, so instead we take the slightly less efficient route, but will be
275                // immediately informed if somehow the above assumption is broken. In this case,
276                // we could always wrap the list of statements at this point with a CompoundStmt,
277                // but it seems reasonable at the moment for this to be done by genImplicitCall
278                // itself. It is possible that genImplicitCall produces no statements (e.g. if
279                // an array type does not have a dimension). In this case, it's fine to ignore
280                // the object for the purposes of construction.
281                assert( ctor.size() == dtor.size() && ctor.size() <= 1 );
282                if ( ctor.size() == 1 ) {
283                        // need to remember init expression, in case no ctors exist
284                        // if ctor does exist, want to use ctor expression instead of init
285                        // push this decision to the resolver
286                        assert( dynamic_cast< ImplicitCtorDtorStmt * > ( ctor.front() ) && dynamic_cast< ImplicitCtorDtorStmt * > ( dtor.front() ) );
287                        return new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() );
288                }
289                return nullptr;
290        }
291
[d24d4e1]292        void CtorDtor::previsit( ObjectDecl * objDecl ) {
[1ba88a0]293                handleDWT( objDecl );
294                // hands off if @=, extern, builtin, etc.
[a4dd728]295                // even if unmanaged, try to construct global or static if initializer is not constexpr, since this is not legal C
296                if ( tryConstruct( objDecl ) && ( isManaged( objDecl ) || ((! inFunction || objDecl->get_storageClasses().is_static ) && ! isConstExpr( objDecl->get_init() ) ) ) ) {
[1ba88a0]297                        // constructed objects cannot be designated
[a4dd728]298                        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 @=.\n", objDecl );
[dcd73d1]299                        // constructed objects should not have initializers nested too deeply
300                        if ( ! checkInitDepth( objDecl ) ) throw SemanticError( "Managed object's initializer is too deep ", objDecl );
[1ba88a0]301
[f0121d7]302                        objDecl->set_init( genCtorInit( objDecl ) );
[974906e2]303                }
304        }
305
[d24d4e1]306        void CtorDtor::previsit( FunctionDecl *functionDecl ) {
307                GuardValue( inFunction );
[1ba88a0]308                inFunction = true;
309
310                handleDWT( functionDecl );
311
[d24d4e1]312                GuardScope( managedTypes );
[1ba88a0]313                // go through assertions and recursively add seen ctor/dtors
[8c49c0e]314                for ( auto & tyDecl : functionDecl->get_functionType()->get_forall() ) {
[1ba88a0]315                        for ( DeclarationWithType *& assertion : tyDecl->get_assertions() ) {
[a8e64c4]316                                handleDWT( assertion );
[1ba88a0]317                        }
318                }
319
[d24d4e1]320                PassVisitor<CtorDtor> newCtorDtor;
321                newCtorDtor.pass = *this;
322                maybeAccept( functionDecl->get_statements(), newCtorDtor );
323                visit_children = false;  // do not try and construct parameters or forall parameters - must happen after maybeAccept
[02c7d04]324        }
[1ba88a0]325
[d24d4e1]326        void CtorDtor::previsit( StructDecl *aggregateDecl ) {
327                visit_children = false; // do not try to construct and destruct aggregate members
328
[1ba88a0]329                // don't construct members, but need to take note if there is a managed member,
330                // because that means that this type is also managed
331                for ( Declaration * member : aggregateDecl->get_members() ) {
332                        if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
333                                if ( isManaged( field ) ) {
[23c4aa8]334                                        StructInstType inst( Type::Qualifiers(), aggregateDecl );
335                                        managedTypes.insert( SymTab::Mangler::mangle( &inst ) );
[1ba88a0]336                                        break;
337                                }
338                        }
339                }
340        }
341
[9ff56e7]342        void CtorDtor::previsit( __attribute__((unused)) CompoundStmt * compoundStmt ) {
[d24d4e1]343                GuardScope( managedTypes );
[1ba88a0]344        }
[42e2ad7]345} // namespace InitTweak
346
[51587aa]347// Local Variables: //
348// tab-width: 4 //
349// mode: c++ //
350// compile-command: "make install" //
351// End: //
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