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 | // TypeEnvironment.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 12:19:47 2015 |
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11 | // Last Modified By : Peter A. Buhr |
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12 | // Last Modified On : Sun May 17 12:23:36 2015 |
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13 | // Update Count : 3 |
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14 | // |
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15 | |
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16 | #include <cassert> // for assert |
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17 | #include <algorithm> // for copy, set_intersection |
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18 | #include <iterator> // for ostream_iterator, insert_iterator |
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19 | #include <utility> // for pair, move |
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20 | |
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21 | #include "Common/InternedString.h" // for interned_string |
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22 | #include "Common/PassVisitor.h" // for PassVisitor<GcTracer> |
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23 | #include "Common/utility.h" // for maybeClone |
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24 | #include "SymTab/Indexer.h" // for Indexer |
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25 | #include "SynTree/GcTracer.h" // for PassVisitor<GcTracer> |
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26 | #include "SynTree/Type.h" // for Type, FunctionType, Type::Fora... |
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27 | #include "SynTree/TypeSubstitution.h" // for TypeSubstitution |
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28 | #include "TypeEnvironment.h" |
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29 | #include "Unify.h" // for unifyInexact |
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30 | |
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31 | namespace ResolvExpr { |
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32 | void printAssertionSet( const AssertionSet &assertions, std::ostream &os, int indent ) { |
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33 | for ( AssertionSet::const_iterator i = assertions.begin(); i != assertions.end(); ++i ) { |
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34 | i->first->print( os, indent ); |
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35 | if ( i->second.isUsed ) { |
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36 | os << "(used)"; |
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37 | } else { |
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38 | os << "(not used)"; |
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39 | } // if |
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40 | } // for |
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41 | } |
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42 | |
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43 | void printOpenVarSet( const OpenVarSet &openVars, std::ostream &os, int indent ) { |
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44 | os << std::string( indent, ' ' ); |
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45 | for ( OpenVarSet::const_iterator i = openVars.begin(); i != openVars.end(); ++i ) { |
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46 | os << i->first << "(" << i->second << ") "; |
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47 | } // for |
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48 | } |
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49 | |
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50 | #if 0 |
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51 | void EqvClass::initialize( const EqvClass &src, EqvClass &dest ) { |
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52 | dest.vars = src.vars; |
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53 | dest.type = maybeClone( src.type ); |
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54 | dest.allowWidening = src.allowWidening; |
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55 | dest.data = src.data; |
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56 | } |
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57 | |
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58 | EqvClass::EqvClass() : vars(), type( 0 ), allowWidening( true ), data() {} |
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59 | |
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60 | EqvClass::EqvClass( std::vector<interned_string>&& vs, BoundType&& bound ) |
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61 | : vars( vs.begin(), vs.end() ), type( maybeClone( bound.type ) ), |
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62 | allowWidening( bound.allowWidening ), data( bound.data ) {} |
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63 | |
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64 | EqvClass::EqvClass( const EqvClass &other ) { |
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65 | initialize( other, *this ); |
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66 | } |
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67 | |
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68 | EqvClass &EqvClass::operator=( const EqvClass &other ) { |
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69 | if ( this == &other ) return *this; |
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70 | initialize( other, *this ); |
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71 | return *this; |
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72 | } |
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73 | |
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74 | void EqvClass::print( std::ostream &os, Indenter indent ) const { |
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75 | os << "( "; |
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76 | std::copy( vars.begin(), vars.end(), std::ostream_iterator< std::string >( os, " " ) ); |
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77 | os << ")"; |
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78 | if ( type ) { |
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79 | os << " -> "; |
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80 | type->print( os, indent+1 ); |
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81 | } // if |
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82 | if ( ! allowWidening ) { |
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83 | os << " (no widening)"; |
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84 | } // if |
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85 | os << std::endl; |
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86 | } |
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87 | |
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88 | const EqvClass* TypeEnvironment::lookup( const std::string &var ) const { |
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89 | for ( std::list< EqvClass >::const_iterator i = env.begin(); i != env.end(); ++i ) { |
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90 | if ( i->vars.find( var ) != i->vars.end() ) { |
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91 | /// std::cout << var << " is in class "; |
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92 | /// i->print( std::cout ); |
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93 | return &*i; |
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94 | } |
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95 | /// std::cout << var << " is not in class "; |
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96 | /// i->print( std::cout ); |
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97 | } // for |
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98 | return nullptr; |
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99 | } |
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100 | #endif |
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101 | |
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102 | std::pair<interned_string, interned_string> TypeEnvironment::mergeClasses( |
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103 | interned_string root1, interned_string root2 ) { |
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104 | // merge classes |
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105 | Classes* newClasses = classes->merge( root1, root2 ); |
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106 | |
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107 | // determine new root |
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108 | assertf(classes->get_mode() == Classes::REMFROM, "classes updated to REMFROM by merge"); |
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109 | auto ret = std::make_pair( classes->get_root(), classes->get_child ); |
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110 | |
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111 | // finalize classes |
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112 | classes = newClasses; |
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113 | return ret; |
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114 | } |
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115 | |
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116 | ClassRef TypeEnvironment::lookup( interned_string var ) const { |
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117 | interned_string root = classes->find_or_default( var, nullptr ); |
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118 | if ( root ) return { this, root }; |
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119 | else return { nullptr, var }; |
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120 | } |
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121 | |
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122 | bool tyVarCompatible( const TypeDecl::Data & data, Type *type ) { |
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123 | switch ( data.kind ) { |
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124 | case TypeDecl::Dtype: |
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125 | // to bind to an object type variable, the type must not be a function type. |
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126 | // if the type variable is specified to be a complete type then the incoming |
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127 | // type must also be complete |
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128 | // xxx - should this also check that type is not a tuple type and that it's not a ttype? |
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129 | return ! isFtype( type ) && (! data.isComplete || type->isComplete() ); |
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130 | case TypeDecl::Ftype: |
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131 | return isFtype( type ); |
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132 | case TypeDecl::Ttype: |
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133 | // ttype unifies with any tuple type |
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134 | return dynamic_cast< TupleType * >( type ) || Tuples::isTtype( type ); |
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135 | } // switch |
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136 | return false; |
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137 | } |
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138 | |
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139 | bool TypeEnvironment::bindVar( TypeInstType* typeInst, Type* bindTo, |
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140 | const TypeDecl::Data& data, AssertionSet& need, AssertionSet& have, |
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141 | const OpenVarSet& openVars, WidenMode widenMode, const SymTab::Indexer& indexer ) { |
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142 | // remove references from other, so that type variables can only bind to value types |
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143 | bindTo = bindTo->stripReferences(); |
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144 | |
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145 | auto tyVar = openVars.find( typeInst->get_name() ); |
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146 | assert( tyVar != openVars.end() ); |
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147 | if ( ! tyVarCompatible( tyVar->second, other ) ) return false; |
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148 | |
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149 | if ( occurs( bindTo, typeInst->get_name(), *this ) ) return false; |
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150 | |
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151 | if ( ClassRef curClass = lookup( typeInst->get_name() ) ) { |
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152 | BoundType curData = curClass.get_bound(); |
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153 | if ( curData.type ) { |
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154 | Type* common = nullptr; |
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155 | // attempt to unify equivalence class type (which needs its qualifiers restored) |
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156 | // with the target type |
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157 | Type* newType = curData.type->clone(); |
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158 | newType->get_qualifiers() = typeInst->get_qualifiers(); |
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159 | if ( unifyInexact( newType, bindTo, *this, need, have, openVars, |
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160 | widenMode & WidenMode{ curData.allowWidening, true }, indexer, common ) ) { |
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161 | if ( common ) { |
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162 | // update bound type to common type |
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163 | common->get_qualifiers() = Type::Qualifiers{}; |
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164 | curData.type = common; |
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165 | bindings = bindings->set( curClass.update_root(), curData ); |
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166 | } |
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167 | return true; |
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168 | } else return false; |
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169 | } else { |
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170 | // update bound type to other type |
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171 | curData.type = bindTo->clone(); |
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172 | curData.type->get_qualifiers() = Type::Qualifiers{}; |
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173 | curData.allowWidening = widenMode.widenFirst && widenMode.widenSecond; |
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174 | bindings = bindings->set( curClass.get_root(), curData ); |
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175 | } |
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176 | } else { |
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177 | // make new class consisting entirely of this variable |
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178 | BoundType curData{ bindTo->clone(), widenMode.first && widenMode.second, data }; |
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179 | curData.type->get_qualifiers() = Type::Qualifiers{}; |
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180 | classes = classes->add( curClass.get_root() ); |
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181 | bindings = bindings->set( curClass.get_root(), curData ); |
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182 | } |
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183 | return true; |
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184 | } |
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185 | |
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186 | bool TypeEnvironment::bindVarToVar( TypeInstType* var1, TypeInstType* var2, |
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187 | const TypeDecl::Data& data, AssertionSet& need, AssertionSet& have, |
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188 | const OpenVarSet& openVars, WidenMode widenMode, const SymTab::Indexer& indexer ) { |
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189 | ClassRef class1 = env.lookup( var1->get_name() ); |
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190 | ClassRef class2 = env.lookup( var2->get_name() ); |
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191 | |
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192 | // exit early if variables already bound together |
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193 | if ( class1 && class2 && class1 == class2 ) { |
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194 | BoundType data1 = class1.get_bound(); |
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195 | // narrow the binding if needed |
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196 | if ( data1.allowWidening && widenMode.first != widenMode.second ) { |
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197 | data1.allowWidening = false; |
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198 | bindings = bindings->set( class1.get_root(), data1 ); |
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199 | } |
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200 | return true; |
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201 | } |
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202 | |
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203 | BoundType data1 = class1 ? class1.get_bound() : BoundType{}; |
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204 | BoundType data2 = class2 ? class2.get_bound() : BoundType{}; |
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205 | |
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206 | bool widen1 = data1.allowWidening && widenMode.widenFirst; |
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207 | bool widen2 = data2.allowWidening && widenMode.widenSecond; |
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208 | |
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209 | if ( data1.type && data2.type ) { |
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210 | // attempt to unify bound classes |
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211 | Type* common = nullptr; |
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212 | if ( unifyInexact( data1.type->clone(), data2.type->clone(), *this, need, have, |
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213 | openVars, WidenMode{ widen1, widen2 }, indexer, common ) ) { |
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214 | // merge type variables |
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215 | interned_string root = mergeClasses( class1.update_root(), class2.update_root() ); |
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216 | // update bindings |
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217 | data1.allowWidening = widen1 && widen2; |
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218 | if ( common ) { |
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219 | common->get_qualifiers() = Type::Qualifiers{}; |
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220 | data1.type = common; |
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221 | } |
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222 | bindings = bindings->set( root, data1 ); |
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223 | } else return false; |
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224 | } else if ( class1 && class2 ) { |
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225 | // both classes exist, only one bound -- merge type variables |
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226 | auto merged = mergeClasses( class1.get_root(), class2.get_root() ); |
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227 | // remove subordinate binding |
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228 | bindings = bindings->erase( merged.second ); |
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229 | // update root binding (narrow widening as needed, or set new binding for changed root) |
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230 | if ( data1.type ) { |
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231 | if ( data1.allowWidening != widen1 ) { |
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232 | data1.allowWidening = widen1; |
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233 | bindings = bindings->set( merged.first, data1 ); |
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234 | } else if ( merged.first == class2.get_root() ) { |
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235 | bindings = bindings->set( merged.first, data1 ); |
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236 | } |
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237 | } else /* if ( data2.type ) */ { |
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238 | if ( data2.allowWidening != widen2 ) { |
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239 | data2.allowWidening = widen2; |
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240 | bindings = bindings->set( root, data2 ); |
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241 | } else if ( merged.first == class1.get_root() ) { |
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242 | bindings = bindings->set( merged.first, data2 ); |
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243 | } |
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244 | } |
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245 | } else if ( class1 ) { |
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246 | // add unbound var2 to class1 |
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247 | classes = classes->add( class2.get_root() ); |
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248 | auto merged = mergeClasses( class1.get_root(), class2.get_root() ); |
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249 | // update bindings (narrow as needed, or switch binding to root) |
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250 | if ( merged.first == class2.get_root() ) { |
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251 | data1.allowWidening = widen1; |
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252 | bindings = bindings->erase( merged.second )->set( merged.first, data1 ); |
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253 | } else if ( data1.allowWidening != widen1 ) { |
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254 | bindings = bindings->set( merged.first, data1 ); |
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255 | } |
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256 | } else if ( class2 ) { |
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257 | // add unbound var1 to class1 |
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258 | classes = classes->add( class1.get_root() ); |
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259 | auto merged = mergeClasses( class1.get_root(), class2.get_root() ); |
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260 | // update bindings (narrow as needed, or switch binding to root) |
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261 | if ( merged.first == class1.get_root() ) { |
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262 | data2.allowWidening = widen2; |
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263 | bindings = bindings->erase( merged.second )->set( merged.first, data2 ); |
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264 | } else if ( data2.allowWidening != widen2 ) { |
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265 | bindings = bindings->set( merged.first, data2 ); |
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266 | } |
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267 | } else { |
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268 | // make new class with pair of unbound vars |
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269 | classes = classes->add( class1.get_root() )->add( class2.get_root() ); |
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270 | auto merged = mergeClasses( class1.get_root(), class2.get_root() ); |
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271 | bindings = bindings->set( merged.first, BoundType{ nullptr, widen1 && widen2, data } ); |
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272 | } |
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273 | return true; |
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274 | } |
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275 | |
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276 | #if !1 |
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277 | /// Removes any class from env that intersects eqvClass |
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278 | void filterOverlappingClasses( std::list<EqvClass> &env, const EqvClass &eqvClass ) { |
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279 | for ( auto i = env.begin(); i != env.end(); ) { |
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280 | auto next = i; |
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281 | ++next; |
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282 | std::set<std::string> intersection; |
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283 | std::set_intersection( i->vars.begin(), i->vars.end(), eqvClass.vars.begin(), eqvClass.vars.end(), |
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284 | std::inserter( intersection, intersection.begin() ) ); |
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285 | if ( ! intersection.empty() ) { env.erase( i ); } |
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286 | i = next; |
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287 | } |
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288 | } |
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289 | |
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290 | void TypeEnvironment::add( const EqvClass &eqvClass ) { |
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291 | filterOverlappingClasses( env, eqvClass ); |
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292 | env.push_back( eqvClass ); |
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293 | } |
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294 | |
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295 | void TypeEnvironment::add( EqvClass &&eqvClass ) { |
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296 | filterOverlappingClasses( env, eqvClass ); |
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297 | env.push_back( std::move(eqvClass) ); |
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298 | } |
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299 | |
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300 | void TypeEnvironment::add( const Type::ForallList &tyDecls ) { |
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301 | for ( Type::ForallList::const_iterator i = tyDecls.begin(); i != tyDecls.end(); ++i ) { |
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302 | EqvClass newClass; |
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303 | newClass.vars.insert( (*i)->get_name() ); |
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304 | newClass.data = TypeDecl::Data{ (*i) }; |
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305 | env.push_back( newClass ); |
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306 | } // for |
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307 | } |
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308 | |
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309 | void TypeEnvironment::add( const TypeSubstitution & sub ) { |
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310 | EqvClass newClass; |
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311 | for ( auto p : sub ) { |
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312 | newClass.vars.insert( p.first ); |
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313 | newClass.type = p.second->clone(); |
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314 | newClass.allowWidening = false; |
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315 | // Minimal assumptions. Not technically correct, but might be good enough, and |
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316 | // is the best we can do at the moment since information is lost in the |
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317 | // transition to TypeSubstitution |
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318 | newClass.data = TypeDecl::Data{ TypeDecl::Dtype, false }; |
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319 | add( newClass ); |
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320 | } |
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321 | } |
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322 | |
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323 | void TypeEnvironment::makeSubstitution( TypeSubstitution &sub ) const { |
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324 | for ( std::list< EqvClass >::const_iterator theClass = env.begin(); theClass != env.end(); ++theClass ) { |
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325 | for ( std::set< std::string >::const_iterator theVar = theClass->vars.begin(); theVar != theClass->vars.end(); ++theVar ) { |
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326 | /// std::cerr << "adding " << *theVar; |
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327 | if ( theClass->type ) { |
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328 | /// std::cerr << " bound to "; |
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329 | /// theClass->type->print( std::cerr ); |
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330 | /// std::cerr << std::endl; |
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331 | sub.add( *theVar, theClass->type ); |
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332 | } else if ( theVar != theClass->vars.begin() ) { |
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333 | TypeInstType *newTypeInst = new TypeInstType( Type::Qualifiers(), *theClass->vars.begin(), theClass->data.kind == TypeDecl::Ftype ); |
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334 | /// std::cerr << " bound to variable " << *theClass->vars.begin() << std::endl; |
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335 | sub.add( *theVar, newTypeInst ); |
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336 | } // if |
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337 | } // for |
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338 | } // for |
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339 | /// std::cerr << "input env is:" << std::endl; |
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340 | /// print( std::cerr, 8 ); |
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341 | /// std::cerr << "sub is:" << std::endl; |
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342 | /// sub.print( std::cerr, 8 ); |
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343 | sub.normalize(); |
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344 | } |
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345 | |
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346 | void TypeEnvironment::print( std::ostream &os, Indenter indent ) const { |
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347 | for ( std::list< EqvClass >::const_iterator i = env.begin(); i != env.end(); ++i ) { |
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348 | i->print( os, indent ); |
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349 | } // for |
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350 | } |
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351 | |
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352 | std::list< EqvClass >::iterator TypeEnvironment::internal_lookup( const std::string &var ) { |
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353 | for ( std::list< EqvClass >::iterator i = env.begin(); i != env.end(); ++i ) { |
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354 | if ( i->vars.find( var ) == i->vars.end() ) { |
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355 | return i; |
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356 | } // if |
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357 | } // for |
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358 | return env.end(); |
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359 | } |
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360 | |
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361 | void TypeEnvironment::simpleCombine( const TypeEnvironment &second ) { |
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362 | env.insert( env.end(), second.env.begin(), second.env.end() ); |
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363 | } |
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364 | |
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365 | void TypeEnvironment::extractOpenVars( OpenVarSet &openVars ) const { |
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366 | for ( std::list< EqvClass >::const_iterator eqvClass = env.begin(); eqvClass != env.end(); ++eqvClass ) { |
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367 | for ( std::set< std::string >::const_iterator var = eqvClass->vars.begin(); var != eqvClass->vars.end(); ++var ) { |
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368 | openVars[ *var ] = eqvClass->data; |
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369 | } // for |
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370 | } // for |
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371 | } |
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372 | |
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373 | void TypeEnvironment::addActual( const TypeEnvironment& actualEnv, OpenVarSet& openVars ) { |
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374 | for ( const EqvClass& c : actualEnv ) { |
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375 | EqvClass c2 = c; |
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376 | c2.allowWidening = false; |
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377 | for ( const std::string& var : c2.vars ) { |
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378 | openVars[ var ] = c2.data; |
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379 | } |
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380 | env.push_back( std::move(c2) ); |
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381 | } |
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382 | } |
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383 | |
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384 | std::ostream & operator<<( std::ostream & out, const TypeEnvironment & env ) { |
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385 | env.print( out ); |
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386 | return out; |
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387 | } |
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388 | #endif |
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389 | |
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390 | PassVisitor<GcTracer> & operator<<( PassVisitor<GcTracer> & gc, const TypeEnvironment & env ) { |
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391 | for ( ClassRef c : env ) { |
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392 | maybeAccept( c.get_bound().type, gc ); |
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393 | } |
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394 | return gc; |
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395 | } |
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396 | } // namespace ResolvExpr |
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397 | |
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398 | // Local Variables: // |
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399 | // tab-width: 4 // |
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400 | // mode: c++ // |
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401 | // compile-command: "make install" // |
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402 | // End: // |
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