[a5f0529] | 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 | // ExpandCasts.cc -- |
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| 8 | // |
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| 9 | // Author : Andrew Beach |
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| 10 | // Created On : Mon Jul 24 13:59:00 2017 |
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| 11 | // Last Modified By : Andrew Beach |
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[cbce272] | 12 | // Last Modified On : Tus Aug 2 14:59:00 2017 |
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| 13 | // Update Count : 1 |
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[a5f0529] | 14 | // |
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| 15 | |
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| 16 | #include "ExpandCasts.h" |
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| 17 | #include "Common/PassVisitor.h" |
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| 18 | |
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| 19 | namespace Virtual { |
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| 20 | |
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| 21 | /* Currently virtual depends on the rather brittle name matching between |
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| 22 | * a (strict/explicate) virtual type, its vtable type and the vtable |
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| 23 | * instance. |
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| 24 | * A stronger implementation, would probably keep track of those triads |
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| 25 | * and use that information to create better error messages. |
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| 26 | */ |
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| 27 | |
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| 28 | std::string get_vtable_name( std::string const & name ) { |
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| 29 | return name + "_vtable"; |
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| 30 | } |
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| 31 | |
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| 32 | std::string get_vtable_inst_name( std::string const & name ) { |
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| 33 | return std::string("_") + get_vtable_name( name ) + "_instance"; |
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| 34 | } |
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| 35 | |
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| 36 | std::string get_vtable_name_root( std::string const & name ) { |
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| 37 | return name.substr(0, name.size() - 7 ); |
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| 38 | } |
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| 39 | |
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| 40 | std::string get_vtable_inst_name_root( std::string const & name ) { |
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| 41 | return get_vtable_name_root( name.substr(1, name.size() - 10 ) ); |
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| 42 | } |
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| 43 | |
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| 44 | bool is_vtable_name( std::string const & name ) { |
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| 45 | return (name.substr( name.size() - 7 ) == "_vtable" ); |
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| 46 | } |
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| 47 | |
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| 48 | bool is_vtable_inst_name( std::string const & name ) { |
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| 49 | return 17 < name.size() && |
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| 50 | name == get_vtable_inst_name( get_vtable_inst_name_root( name ) ); |
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| 51 | } |
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| 52 | |
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| 53 | class VirtualCastCore { |
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| 54 | std::map<std::string, ObjectDecl *> vtable_instances; |
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| 55 | FunctionDecl *vcast_decl; |
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| 56 | StructDecl *pvt_decl; |
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| 57 | |
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| 58 | Type * pointer_to_pvt(int level_of_indirection) { |
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| 59 | Type * type = new StructInstType( |
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| 60 | Type::Qualifiers( Type::Const ), pvt_decl ); |
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| 61 | for (int i = 0 ; i < level_of_indirection ; ++i) { |
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| 62 | type = new PointerType( noQualifiers, type ); |
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| 63 | } |
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| 64 | return type; |
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| 65 | } |
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| 66 | |
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| 67 | public: |
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| 68 | VirtualCastCore() : |
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| 69 | vtable_instances(), vcast_decl( nullptr ), pvt_decl( nullptr ) |
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| 70 | {} |
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| 71 | |
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| 72 | void premutate( FunctionDecl * functionDecl ); |
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| 73 | void premutate( StructDecl * structDecl ); |
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| 74 | void premutate( ObjectDecl * objectDecl ); |
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| 75 | |
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| 76 | Expression * postmutate( VirtualCastExpr * castExpr ); |
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| 77 | }; |
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| 78 | |
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| 79 | void VirtualCastCore::premutate( FunctionDecl * functionDecl ) { |
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[cbce272] | 80 | if ( (! vcast_decl) && |
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[a5f0529] | 81 | functionDecl->get_name() == "__cfa__virtual_cast" ) { |
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| 82 | vcast_decl = functionDecl; |
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| 83 | } |
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| 84 | } |
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| 85 | |
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| 86 | void VirtualCastCore::premutate( StructDecl * structDecl ) { |
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| 87 | if ( pvt_decl || ! structDecl->has_body() ) { |
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| 88 | return; |
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| 89 | } else if ( structDecl->get_name() == "__cfa__parent_vtable" ) { |
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| 90 | pvt_decl = structDecl; |
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| 91 | } |
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| 92 | } |
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| 93 | |
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| 94 | void VirtualCastCore::premutate( ObjectDecl * objectDecl ) { |
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| 95 | if ( is_vtable_inst_name( objectDecl->get_name() ) ) { |
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| 96 | vtable_instances[objectDecl->get_name()] = objectDecl; |
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| 97 | } |
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| 98 | } |
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| 99 | |
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| 100 | Expression * VirtualCastCore::postmutate( VirtualCastExpr * castExpr ) { |
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| 101 | assertf( castExpr->get_result(), "Virtual Cast target not found before expansion." ); |
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| 102 | |
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[cbce272] | 103 | assert( vcast_decl ); |
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[a5f0529] | 104 | assert( pvt_decl ); |
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| 105 | |
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| 106 | // May only cast to a pointer or reference type. |
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| 107 | // A earlier validation should give a syntax error, this is |
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[cbce272] | 108 | // just to make sure errors don't creep during translation. |
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| 109 | // Move to helper with more detailed error messages. |
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[a5f0529] | 110 | PointerType * target_type = |
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| 111 | dynamic_cast<PointerType *>( castExpr->get_result() ); |
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[cbce272] | 112 | assert( target_type ); |
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[a5f0529] | 113 | |
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| 114 | StructInstType * target_struct = |
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| 115 | dynamic_cast<StructInstType *>( target_type->get_base() ); |
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[cbce272] | 116 | assert( target_struct ); |
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| 117 | |
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[a5f0529] | 118 | StructDecl * target_decl = target_struct->get_baseStruct(); |
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| 119 | |
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| 120 | std::map<std::string, ObjectDecl *>::iterator found = |
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| 121 | vtable_instances.find( |
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| 122 | get_vtable_inst_name( target_decl->get_name() ) ); |
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| 123 | if ( vtable_instances.end() == found ) { |
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| 124 | assertf( false, "virtual table instance not found." ); |
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| 125 | } |
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| 126 | ObjectDecl * table = found->second; |
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| 127 | |
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| 128 | Expression * result = new CastExpr( |
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[cbce272] | 129 | //new ApplicationExpr( |
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| 130 | //new AddressExpr( new VariableExpr( vcast_decl ) ), |
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| 131 | //new CastExpr( new VariableExpr( vcast_decl ), |
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| 132 | // new PointerType( noQualifiers, |
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| 133 | // vcast_decl->get_type()->clone() |
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| 134 | // ) |
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| 135 | // ), |
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[a5f0529] | 136 | new UntypedExpr( new NameExpr( "__cfa__virtual_cast" ), { |
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[cbce272] | 137 | new CastExpr( |
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| 138 | new AddressExpr( new VariableExpr( table ) ), |
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| 139 | pointer_to_pvt(1) |
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| 140 | ), |
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| 141 | new CastExpr( |
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| 142 | castExpr->get_arg(), |
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| 143 | pointer_to_pvt(2) |
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| 144 | ) |
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| 145 | } ), |
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| 146 | castExpr->get_result()->clone() |
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[a5f0529] | 147 | ); |
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| 148 | |
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| 149 | castExpr->set_arg( nullptr ); |
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| 150 | castExpr->set_result( nullptr ); |
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| 151 | delete castExpr; |
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| 152 | return result; |
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| 153 | } |
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| 154 | |
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| 155 | void expandCasts( std::list< Declaration * > & translationUnit ) { |
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| 156 | PassVisitor<VirtualCastCore> translator; |
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| 157 | mutateAll( translationUnit, translator ); |
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| 158 | } |
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| 159 | } |
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