| 1 | // |
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo |
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| 3 | // |
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| 4 | // The contents of this file are covered under the licence agreement in the |
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| 5 | // file "LICENCE" distributed with Cforall. |
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| 6 | // |
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| 7 | // CastCost.cc -- |
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| 8 | // |
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| 9 | // Author : Richard C. Bilson |
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| 10 | // Created On : Sun May 17 06:57:43 2015 |
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| 11 | // Last Modified By : Peter A. Buhr |
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| 12 | // Last Modified On : Tue Feb 2 15:34:36 2016 |
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| 13 | // Update Count : 7 |
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| 14 | // |
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| 15 | |
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| 16 | #include <cassert> // for assert |
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| 17 | |
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| 18 | #include "ConversionCost.h" // for ConversionCost |
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| 19 | #include "Cost.h" // for Cost, Cost::infinity |
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| 20 | #include "ResolvExpr/TypeEnvironment.h" // for TypeEnvironment, EqvClass |
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| 21 | #include "SymTab/Indexer.h" // for Indexer |
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| 22 | #include "SynTree/Declaration.h" // for TypeDecl, NamedTypeDecl |
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| 23 | #include "SynTree/Type.h" // for PointerType, Type, TypeInstType |
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| 24 | #include "typeops.h" // for typesCompatibleIgnoreQualifiers |
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| 25 | |
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| 26 | |
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| 27 | namespace ResolvExpr { |
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| 28 | class CastCost : public ConversionCost { |
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| 29 | public: |
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| 30 | CastCost( Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env ); |
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| 31 | |
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| 32 | virtual void visit( BasicType *basicType ); |
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| 33 | virtual void visit( PointerType *pointerType ); |
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| 34 | }; |
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| 35 | |
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| 36 | Cost castCost( Type *src, Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env ) { |
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| 37 | if ( TypeInstType *destAsTypeInst = dynamic_cast< TypeInstType* >( dest ) ) { |
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| 38 | EqvClass eqvClass; |
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| 39 | NamedTypeDecl *namedType; |
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| 40 | if ( env.lookup( destAsTypeInst->get_name(), eqvClass ) ) { |
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| 41 | if ( eqvClass.type ) { |
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| 42 | return castCost( src, eqvClass.type, indexer, env ); |
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| 43 | } else { |
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| 44 | return Cost::infinity; |
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| 45 | } |
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| 46 | } else if ( ( namedType = indexer.lookupType( destAsTypeInst->get_name() ) ) ) { |
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| 47 | // all typedefs should be gone by this point |
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| 48 | TypeDecl *type = strict_dynamic_cast< TypeDecl* >( namedType ); |
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| 49 | if ( type->get_base() ) { |
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| 50 | return castCost( src, type->get_base(), indexer, env ) + Cost::safe; |
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| 51 | } // if |
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| 52 | } // if |
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| 53 | } // if |
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| 54 | if ( typesCompatibleIgnoreQualifiers( src, dest, indexer, env ) ) { |
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| 55 | return Cost::zero; |
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| 56 | } else if ( dynamic_cast< VoidType* >( dest ) ) { |
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| 57 | return Cost::safe; |
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| 58 | } else if ( ReferenceType * refType = dynamic_cast< ReferenceType * > ( dest ) ) { |
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| 59 | return convertToReferenceCost( src, refType, indexer, env, [](Type * t1, Type * t2, const TypeEnvironment & env, const SymTab::Indexer & indexer) { |
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| 60 | return ptrsCastable( t1, t2, env, indexer ); |
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| 61 | }); |
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| 62 | } else { |
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| 63 | CastCost converter( dest, indexer, env ); |
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| 64 | src->accept( converter ); |
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| 65 | if ( converter.get_cost() == Cost::infinity ) { |
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| 66 | return Cost::infinity; |
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| 67 | } else { |
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| 68 | // xxx - why are we adding cost 0 here? |
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| 69 | return converter.get_cost() + Cost::zero; |
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| 70 | } // if |
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| 71 | } // if |
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| 72 | } |
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| 73 | |
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| 74 | CastCost::CastCost( Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env ) |
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| 75 | : ConversionCost( dest, indexer, env ) { |
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| 76 | } |
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| 77 | |
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| 78 | void CastCost::visit( BasicType *basicType ) { |
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| 79 | PointerType *destAsPointer = dynamic_cast< PointerType* >( dest ); |
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| 80 | if ( destAsPointer && basicType->isInteger() ) { |
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| 81 | // necessary for, e.g. unsigned long => void* |
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| 82 | cost = Cost::unsafe; |
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| 83 | } else { |
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| 84 | cost = conversionCost( basicType, dest, indexer, env ); |
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| 85 | } // if |
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| 86 | } |
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| 87 | |
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| 88 | void CastCost::visit( PointerType *pointerType ) { |
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| 89 | if ( PointerType *destAsPtr = dynamic_cast< PointerType* >( dest ) ) { |
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| 90 | if ( pointerType->get_qualifiers() <= destAsPtr->get_qualifiers() && typesCompatibleIgnoreQualifiers( pointerType->get_base(), destAsPtr->get_base(), indexer, env ) ) { |
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| 91 | cost = Cost::safe; |
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| 92 | } else { |
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| 93 | TypeEnvironment newEnv( env ); |
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| 94 | newEnv.add( pointerType->get_forall() ); |
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| 95 | newEnv.add( pointerType->get_base()->get_forall() ); |
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| 96 | int castResult = ptrsCastable( pointerType->get_base(), destAsPtr->get_base(), newEnv, indexer ); |
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| 97 | if ( castResult > 0 ) { |
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| 98 | cost = Cost::safe; |
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| 99 | } else if ( castResult < 0 ) { |
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| 100 | cost = Cost::infinity; |
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| 101 | } // if |
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| 102 | } // if |
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| 103 | } else if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) { |
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| 104 | if ( destAsBasic->isInteger() ) { |
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| 105 | // necessary for, e.g. void* => unsigned long |
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| 106 | cost = Cost::unsafe; |
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| 107 | } // if |
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| 108 | } |
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| 109 | } |
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| 110 | } // namespace ResolvExpr |
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| 111 | |
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| 112 | // Local Variables: // |
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| 113 | // tab-width: 4 // |
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| 114 | // mode: c++ // |
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| 115 | // compile-command: "make install" // |
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| 116 | // End: // |
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