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 | // GenInit.cc -- |
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8 | // |
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9 | // Author : Rob Schluntz |
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10 | // Created On : Mon May 18 07:44:20 2015 |
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11 | // Last Modified By : Rob Schluntz |
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12 | // Last Modified On : Fri May 13 11:37:48 2016 |
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13 | // Update Count : 166 |
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14 | // |
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15 | |
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16 | #include <stack> |
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17 | #include <list> |
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18 | #include "GenInit.h" |
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19 | #include "InitTweak.h" |
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20 | #include "SynTree/Declaration.h" |
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21 | #include "SynTree/Type.h" |
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22 | #include "SynTree/Expression.h" |
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23 | #include "SynTree/Statement.h" |
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24 | #include "SynTree/Initializer.h" |
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25 | #include "SynTree/Mutator.h" |
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26 | #include "SymTab/Autogen.h" |
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27 | #include "GenPoly/PolyMutator.h" |
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28 | #include "GenPoly/DeclMutator.h" |
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29 | |
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30 | namespace InitTweak { |
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31 | namespace { |
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32 | const std::list<Label> noLabels; |
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33 | const std::list<Expression *> noDesignators; |
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34 | } |
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35 | |
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36 | class ReturnFixer : public GenPoly::PolyMutator { |
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37 | public: |
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38 | /// consistently allocates a temporary variable for the return value |
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39 | /// of a function so that anything which the resolver decides can be constructed |
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40 | /// into the return type of a function can be returned. |
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41 | static void makeReturnTemp( std::list< Declaration * > &translationUnit ); |
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42 | |
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43 | ReturnFixer(); |
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44 | |
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45 | virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ); |
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46 | |
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47 | virtual Statement * mutate( ReturnStmt * returnStmt ); |
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48 | |
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49 | protected: |
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50 | std::list<DeclarationWithType*> returnVals; |
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51 | UniqueName tempNamer; |
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52 | std::string funcName; |
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53 | }; |
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54 | |
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55 | class CtorDtor : public GenPoly::PolyMutator { |
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56 | public: |
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57 | /// create constructor and destructor statements for object declarations. |
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58 | /// the actual call statements will be added in after the resolver has run |
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59 | /// so that the initializer expression is only removed if a constructor is found |
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60 | /// and the same destructor call is inserted in all of the appropriate locations. |
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61 | static void generateCtorDtor( std::list< Declaration * > &translationUnit ); |
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62 | |
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63 | CtorDtor() : inFunction( false ) {} |
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64 | |
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65 | virtual DeclarationWithType * mutate( ObjectDecl * ); |
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66 | virtual DeclarationWithType * mutate( FunctionDecl *functionDecl ); |
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67 | // should not traverse into any of these declarations to find objects |
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68 | // that need to be constructed or destructed |
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69 | virtual Declaration* mutate( StructDecl *aggregateDecl ) { return aggregateDecl; } |
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70 | virtual Declaration* mutate( UnionDecl *aggregateDecl ) { return aggregateDecl; } |
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71 | virtual Declaration* mutate( EnumDecl *aggregateDecl ) { return aggregateDecl; } |
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72 | virtual Declaration* mutate( TraitDecl *aggregateDecl ) { return aggregateDecl; } |
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73 | virtual TypeDecl* mutate( TypeDecl *typeDecl ) { return typeDecl; } |
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74 | virtual Declaration* mutate( TypedefDecl *typeDecl ) { return typeDecl; } |
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75 | |
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76 | virtual Type * mutate( FunctionType *funcType ) { return funcType; } |
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77 | |
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78 | protected: |
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79 | bool inFunction; |
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80 | }; |
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81 | |
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82 | class HoistArrayDimension : public GenPoly::DeclMutator { |
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83 | public: |
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84 | typedef GenPoly::DeclMutator Parent; |
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85 | |
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86 | /// hoist dimension from array types in object declaration so that it uses a single |
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87 | /// const variable of type size_t, so that side effecting array dimensions are only |
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88 | /// computed once. |
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89 | static void hoistArrayDimension( std::list< Declaration * > & translationUnit ); |
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90 | |
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91 | private: |
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92 | DeclarationWithType * mutate( ObjectDecl * objectDecl ); |
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93 | // should not traverse into any of these declarations to find objects |
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94 | // that need to be constructed or destructed |
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95 | virtual Declaration* mutate( StructDecl *aggregateDecl ) { return aggregateDecl; } |
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96 | virtual Declaration* mutate( UnionDecl *aggregateDecl ) { return aggregateDecl; } |
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97 | virtual Declaration* mutate( EnumDecl *aggregateDecl ) { return aggregateDecl; } |
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98 | virtual Declaration* mutate( TraitDecl *aggregateDecl ) { return aggregateDecl; } |
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99 | virtual TypeDecl* mutate( TypeDecl *typeDecl ) { return typeDecl; } |
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100 | virtual Declaration* mutate( TypedefDecl *typeDecl ) { return typeDecl; } |
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101 | |
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102 | virtual Type* mutate( FunctionType *funcType ) { return funcType; } |
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103 | |
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104 | void hoist( Type * type ); |
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105 | |
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106 | DeclarationNode::StorageClass storageclass = DeclarationNode::NoStorageClass; |
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107 | }; |
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108 | |
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109 | void genInit( std::list< Declaration * > & translationUnit ) { |
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110 | ReturnFixer::makeReturnTemp( translationUnit ); |
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111 | HoistArrayDimension::hoistArrayDimension( translationUnit ); |
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112 | CtorDtor::generateCtorDtor( translationUnit ); |
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113 | } |
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114 | |
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115 | void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) { |
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116 | ReturnFixer fixer; |
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117 | mutateAll( translationUnit, fixer ); |
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118 | } |
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119 | |
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120 | ReturnFixer::ReturnFixer() : tempNamer( "_retVal" ) {} |
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121 | |
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122 | Statement *ReturnFixer::mutate( ReturnStmt *returnStmt ) { |
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123 | // update for multiple return values |
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124 | assert( returnVals.size() == 0 || returnVals.size() == 1 ); |
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125 | // hands off if the function returns an lvalue - we don't want to allocate a temporary if a variable's address |
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126 | // is being returned |
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127 | if ( returnStmt->get_expr() && returnVals.size() == 1 && funcName != "?=?" && ! returnVals.front()->get_type()->get_isLvalue() ) { |
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128 | // ensure return value is not destructed by explicitly creating |
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129 | // an empty SingleInit node wherein maybeConstruct is false |
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130 | ObjectDecl *newObj = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, returnVals.front()->get_type()->clone(), new ListInit( std::list<Initializer*>(), noDesignators, false ) ); |
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131 | stmtsToAdd.push_back( new DeclStmt( noLabels, newObj ) ); |
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132 | |
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133 | // and explicitly create the constructor expression separately |
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134 | UntypedExpr *construct = new UntypedExpr( new NameExpr( "?{}" ) ); |
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135 | construct->get_args().push_back( new AddressExpr( new VariableExpr( newObj ) ) ); |
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136 | construct->get_args().push_back( returnStmt->get_expr() ); |
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137 | stmtsToAdd.push_back(new ExprStmt(noLabels, construct)); |
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138 | |
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139 | returnStmt->set_expr( new VariableExpr( newObj ) ); |
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140 | } // if |
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141 | return returnStmt; |
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142 | } |
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143 | |
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144 | DeclarationWithType* ReturnFixer::mutate( FunctionDecl *functionDecl ) { |
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145 | std::list<DeclarationWithType*> oldReturnVals = returnVals; |
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146 | std::string oldFuncName = funcName; |
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147 | |
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148 | FunctionType * type = functionDecl->get_functionType(); |
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149 | returnVals = type->get_returnVals(); |
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150 | funcName = functionDecl->get_name(); |
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151 | DeclarationWithType * decl = Mutator::mutate( functionDecl ); |
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152 | returnVals = oldReturnVals; |
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153 | funcName = oldFuncName; |
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154 | return decl; |
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155 | } |
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156 | |
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157 | void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) { |
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158 | HoistArrayDimension hoister; |
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159 | mutateAll( translationUnit, hoister ); |
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160 | } |
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161 | |
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162 | DeclarationWithType * HoistArrayDimension::mutate( ObjectDecl * objectDecl ) { |
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163 | storageclass = objectDecl->get_storageClass(); |
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164 | DeclarationWithType * temp = Parent::mutate( objectDecl ); |
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165 | hoist( objectDecl->get_type() ); |
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166 | storageclass = DeclarationNode::NoStorageClass; |
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167 | return temp; |
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168 | } |
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169 | |
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170 | void HoistArrayDimension::hoist( Type * type ) { |
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171 | static UniqueName dimensionName( "_array_dim" ); |
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172 | if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) { |
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173 | if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist? |
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174 | |
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175 | // don't need to hoist dimension if it's a constexpr - only need to if there's potential |
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176 | // for side effects. |
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177 | if ( isConstExpr( arrayType->get_dimension() ) ) return; |
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178 | |
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179 | ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageclass, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) ); |
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180 | arrayDimension->get_type()->set_isConst( true ); |
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181 | |
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182 | arrayType->set_dimension( new VariableExpr( arrayDimension ) ); |
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183 | addDeclaration( arrayDimension ); |
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184 | |
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185 | hoist( arrayType->get_base() ); |
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186 | return; |
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187 | } |
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188 | } |
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189 | |
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190 | void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) { |
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191 | CtorDtor ctordtor; |
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192 | mutateAll( translationUnit, ctordtor ); |
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193 | } |
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194 | |
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195 | namespace { |
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196 | Expression * makeCtorDtorExpr( std::string name, ObjectDecl * objDecl, std::list< Expression * > args ) { |
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197 | UntypedExpr * expr = new UntypedExpr( new NameExpr( name ) ); |
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198 | expr->get_args().push_back( new AddressExpr( new VariableExpr( objDecl ) ) ); |
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199 | expr->get_args().splice( expr->get_args().end(), args ); |
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200 | return expr; |
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201 | } |
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202 | } |
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203 | |
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204 | DeclarationWithType * CtorDtor::mutate( ObjectDecl * objDecl ) { |
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205 | // hands off if designated or if @= |
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206 | if ( tryConstruct( objDecl ) ) { |
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207 | if ( inFunction ) { |
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208 | if ( ArrayType * at = dynamic_cast< ArrayType * >( objDecl->get_type() ) ) { |
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209 | // call into makeArrayFunction from validate.cc to generate calls to ctor/dtor for each element of array |
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210 | // TODO: walk initializers and generate appropriate ctor if element has initializer. |
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211 | // Initializer could be nested (depends on the depth of the array type on the object) |
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212 | |
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213 | std::list< Expression * > args = makeInitList( objDecl->get_init() ); |
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214 | if ( args.empty() ) { |
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215 | std::list< Statement * > ctor; |
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216 | std::list< Statement * > dtor; |
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217 | |
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218 | SymTab::genImplicitCall( NULL, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl ); |
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219 | SymTab::genImplicitCall( NULL, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false ); |
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220 | |
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221 | // Currently genArrayCall produces a single Statement - a CompoundStmt |
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222 | // which wraps everything that needs to happen. As such, it's technically |
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223 | // possible to use a Statement ** in the above calls, but this is inherently |
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224 | // unsafe, so instead we take the slightly less efficient route, but will be |
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225 | // immediately informed if somehow the above assumption is broken. In this case, |
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226 | // we could always wrap the list of statements at this point with a CompoundStmt, |
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227 | // but it seems reasonable at the moment for this to be done by genArrayCall |
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228 | // itself |
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229 | assert( ctor.size() == 1 && dynamic_cast< ImplicitCtorDtorStmt * >( ctor.front() ) ); |
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230 | assert( dtor.size() == 1 && dynamic_cast< ImplicitCtorDtorStmt * >( dtor.front() ) ); |
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231 | objDecl->set_init( new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() ) ); |
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232 | } else { |
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233 | // array came with an initializer list: initialize each element |
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234 | // may have more initializers than elements in the array - need to check at each index that |
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235 | // we haven't exceeded size. This requires precomputing the size because it might be a side-effecting |
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236 | // computation. |
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237 | // may have fewer initializers than elements in the array - need to default construct |
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238 | // remaining elements. |
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239 | // might be able to merge this with the case above. |
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240 | |
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241 | } |
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242 | } else { |
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243 | // it's sufficient to attempt to call the ctor/dtor for the given object and its initializer |
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244 | Expression * ctor = makeCtorDtorExpr( "?{}", objDecl, makeInitList( objDecl->get_init() ) ); |
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245 | Expression * dtor = makeCtorDtorExpr( "^?{}", objDecl, std::list< Expression * >() ); |
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246 | |
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247 | // need to remember init expression, in case no ctors exist |
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248 | // if ctor does exist, want to use ctor expression instead of init |
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249 | // push this decision to the resolver |
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250 | ExprStmt * ctorStmt = new ExprStmt( noLabels, ctor ); |
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251 | ExprStmt * dtorStmt = new ExprStmt( noLabels, dtor ); |
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252 | objDecl->set_init( new ConstructorInit( new ImplicitCtorDtorStmt( ctorStmt ), new ImplicitCtorDtorStmt( dtorStmt ), objDecl->get_init() ) ); |
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253 | } |
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254 | } |
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255 | } |
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256 | return Mutator::mutate( objDecl ); |
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257 | } |
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258 | |
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259 | DeclarationWithType * CtorDtor::mutate( FunctionDecl *functionDecl ) { |
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260 | // parameters should not be constructed and destructed, so don't mutate FunctionType |
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261 | bool oldInFunc = inFunction; |
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262 | mutateAll( functionDecl->get_oldDecls(), *this ); |
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263 | inFunction = true; |
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264 | functionDecl->set_statements( maybeMutate( functionDecl->get_statements(), *this ) ); |
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265 | inFunction = oldInFunc; |
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266 | return functionDecl; |
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267 | } |
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268 | } // namespace InitTweak |
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269 | |
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270 | // Local Variables: // |
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271 | // tab-width: 4 // |
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272 | // mode: c++ // |
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273 | // compile-command: "make install" // |
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274 | // End: // |
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