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 : Peter A. Buhr |
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12 | // Last Modified On : Fri Mar 17 09:12:36 2017 |
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13 | // Update Count : 183 |
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14 | // |
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15 | #include "GenInit.h" |
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16 | |
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17 | #include <stddef.h> // for NULL |
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18 | #include <algorithm> // for any_of |
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19 | #include <cassert> // for assert, strict_dynamic_cast, assertf |
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20 | #include <iterator> // for back_inserter, inserter, back_inse... |
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21 | #include <list> // for _List_iterator, list |
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22 | |
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23 | #include "CodeGen/OperatorTable.h" |
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24 | #include "Common/PassVisitor.h" // for PassVisitor, WithGuards, WithShort... |
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25 | #include "Common/SemanticError.h" // for SemanticError |
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26 | #include "Common/UniqueName.h" // for UniqueName |
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27 | #include "Common/utility.h" // for ValueGuard, maybeClone |
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28 | #include "GenPoly/DeclMutator.h" // for DeclMutator |
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29 | #include "GenPoly/GenPoly.h" // for getFunctionType, isPolyType |
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30 | #include "GenPoly/ScopedSet.h" // for ScopedSet, ScopedSet<>::const_iter... |
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31 | #include "InitTweak.h" // for isConstExpr, InitExpander, checkIn... |
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32 | #include "Parser/LinkageSpec.h" // for isOverridable, C |
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33 | #include "SymTab/Autogen.h" // for genImplicitCall, SizeType |
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34 | #include "SymTab/Mangler.h" // for Mangler |
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35 | #include "SynTree/Declaration.h" // for ObjectDecl, DeclarationWithType |
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36 | #include "SynTree/Expression.h" // for VariableExpr, UntypedExpr, Address... |
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37 | #include "SynTree/Initializer.h" // for ConstructorInit, SingleInit, Initi... |
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38 | #include "SynTree/Label.h" // for Label |
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39 | #include "SynTree/Mutator.h" // for mutateAll |
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40 | #include "SynTree/Statement.h" // for CompoundStmt, ImplicitCtorDtorStmt |
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41 | #include "SynTree/Type.h" // for Type, ArrayType, Type::Qualifiers |
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42 | #include "SynTree/Visitor.h" // for acceptAll, maybeAccept |
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43 | |
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44 | namespace InitTweak { |
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45 | namespace { |
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46 | const std::list<Label> noLabels; |
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47 | const std::list<Expression *> noDesignators; |
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48 | } |
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49 | |
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50 | struct ReturnFixer : public WithStmtsToAdd, public WithGuards { |
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51 | /// consistently allocates a temporary variable for the return value |
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52 | /// of a function so that anything which the resolver decides can be constructed |
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53 | /// into the return type of a function can be returned. |
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54 | static void makeReturnTemp( std::list< Declaration * > &translationUnit ); |
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55 | |
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56 | void premutate( FunctionDecl *functionDecl ); |
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57 | void premutate( ReturnStmt * returnStmt ); |
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58 | |
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59 | protected: |
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60 | FunctionType * ftype = nullptr; |
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61 | std::string funcName; |
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62 | }; |
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63 | |
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64 | struct CtorDtor : public WithGuards, public WithShortCircuiting, public WithVisitorRef<CtorDtor> { |
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65 | /// create constructor and destructor statements for object declarations. |
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66 | /// the actual call statements will be added in after the resolver has run |
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67 | /// so that the initializer expression is only removed if a constructor is found |
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68 | /// and the same destructor call is inserted in all of the appropriate locations. |
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69 | static void generateCtorDtor( std::list< Declaration * > &translationUnit ); |
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70 | |
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71 | void previsit( ObjectDecl * ); |
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72 | void previsit( FunctionDecl *functionDecl ); |
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73 | |
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74 | // should not traverse into any of these declarations to find objects |
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75 | // that need to be constructed or destructed |
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76 | void previsit( StructDecl *aggregateDecl ); |
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77 | void previsit( AggregateDecl * ) { visit_children = false; } |
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78 | void previsit( NamedTypeDecl * ) { visit_children = false; } |
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79 | void previsit( FunctionType * ) { visit_children = false; } |
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80 | |
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81 | void previsit( CompoundStmt * compoundStmt ); |
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82 | |
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83 | private: |
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84 | // set of mangled type names for which a constructor or destructor exists in the current scope. |
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85 | // these types require a ConstructorInit node to be generated, anything else is a POD type and thus |
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86 | // should not have a ConstructorInit generated. |
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87 | |
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88 | bool isManaged( ObjectDecl * objDecl ) const ; // determine if object is managed |
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89 | bool isManaged( Type * type ) const; // determine if type is managed |
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90 | void handleDWT( DeclarationWithType * dwt ); // add type to managed if ctor/dtor |
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91 | GenPoly::ScopedSet< std::string > managedTypes; |
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92 | bool inFunction = false; |
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93 | }; |
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94 | |
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95 | struct HoistArrayDimension final : public WithDeclsToAdd, public WithShortCircuiting, public WithGuards { |
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96 | /// hoist dimension from array types in object declaration so that it uses a single |
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97 | /// const variable of type size_t, so that side effecting array dimensions are only |
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98 | /// computed once. |
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99 | static void hoistArrayDimension( std::list< Declaration * > & translationUnit ); |
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100 | |
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101 | void premutate( ObjectDecl * objectDecl ); |
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102 | DeclarationWithType * postmutate( ObjectDecl * objectDecl ); |
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103 | void premutate( FunctionDecl *functionDecl ); |
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104 | // should not traverse into any of these declarations to find objects |
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105 | // that need to be constructed or destructed |
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106 | void premutate( AggregateDecl * ) { visit_children = false; } |
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107 | void premutate( NamedTypeDecl * ) { visit_children = false; } |
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108 | void premutate( FunctionType * ) { visit_children = false; } |
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109 | |
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110 | void hoist( Type * type ); |
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111 | |
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112 | Type::StorageClasses storageClasses; |
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113 | bool inFunction = false; |
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114 | }; |
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115 | |
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116 | void genInit( std::list< Declaration * > & translationUnit ) { |
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117 | ReturnFixer::makeReturnTemp( translationUnit ); |
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118 | HoistArrayDimension::hoistArrayDimension( translationUnit ); |
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119 | CtorDtor::generateCtorDtor( translationUnit ); |
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120 | } |
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121 | |
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122 | void ReturnFixer::makeReturnTemp( std::list< Declaration * > & translationUnit ) { |
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123 | PassVisitor<ReturnFixer> fixer; |
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124 | mutateAll( translationUnit, fixer ); |
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125 | } |
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126 | |
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127 | void ReturnFixer::premutate( ReturnStmt *returnStmt ) { |
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128 | std::list< DeclarationWithType * > & returnVals = ftype->get_returnVals(); |
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129 | assert( returnVals.size() == 0 || returnVals.size() == 1 ); |
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130 | // hands off if the function returns a reference - we don't want to allocate a temporary if a variable's address |
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131 | // is being returned |
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132 | if ( returnStmt->get_expr() && returnVals.size() == 1 && isConstructable( returnVals.front()->get_type() ) ) { |
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133 | // explicitly construct the return value using the return expression and the retVal object |
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134 | assertf( returnVals.front()->get_name() != "", "Function %s has unnamed return value\n", funcName.c_str() ); |
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135 | |
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136 | stmtsToAddBefore.push_back( genCtorDtor( "?{}", dynamic_cast< ObjectDecl *>( returnVals.front() ), returnStmt->get_expr() ) ); |
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137 | |
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138 | // return the retVal object |
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139 | returnStmt->set_expr( new VariableExpr( returnVals.front() ) ); |
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140 | } // if |
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141 | } |
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142 | |
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143 | void ReturnFixer::premutate( FunctionDecl *functionDecl ) { |
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144 | GuardValue( ftype ); |
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145 | GuardValue( funcName ); |
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146 | |
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147 | ftype = functionDecl->type; |
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148 | funcName = functionDecl->name; |
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149 | } |
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150 | |
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151 | // precompute array dimension expression, because constructor generation may duplicate it, |
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152 | // which would be incorrect if it is a side-effecting computation. |
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153 | void HoistArrayDimension::hoistArrayDimension( std::list< Declaration * > & translationUnit ) { |
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154 | PassVisitor<HoistArrayDimension> hoister; |
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155 | mutateAll( translationUnit, hoister ); |
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156 | } |
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157 | |
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158 | void HoistArrayDimension::premutate( ObjectDecl * objectDecl ) { |
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159 | GuardValue( storageClasses ); |
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160 | storageClasses = objectDecl->get_storageClasses(); |
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161 | } |
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162 | |
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163 | DeclarationWithType * HoistArrayDimension::postmutate( ObjectDecl * objectDecl ) { |
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164 | hoist( objectDecl->get_type() ); |
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165 | return objectDecl; |
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166 | } |
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167 | |
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168 | void HoistArrayDimension::hoist( Type * type ) { |
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169 | // if in function, generate const size_t var |
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170 | static UniqueName dimensionName( "_array_dim" ); |
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171 | |
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172 | // C doesn't allow variable sized arrays at global scope or for static variables, so don't hoist dimension. |
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173 | if ( ! inFunction ) return; |
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174 | if ( storageClasses.is_static ) return; |
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175 | |
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176 | if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) { |
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177 | if ( ! arrayType->get_dimension() ) return; // xxx - recursive call to hoist? |
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178 | |
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179 | // don't need to hoist dimension if it's a constexpr - only need to if there's potential for side effects. |
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180 | if ( isConstExpr( arrayType->get_dimension() ) ) return; |
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181 | |
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182 | ObjectDecl * arrayDimension = new ObjectDecl( dimensionName.newName(), storageClasses, LinkageSpec::C, 0, SymTab::SizeType->clone(), new SingleInit( arrayType->get_dimension() ) ); |
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183 | arrayDimension->get_type()->set_const( true ); |
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184 | |
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185 | arrayType->set_dimension( new VariableExpr( arrayDimension ) ); |
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186 | declsToAddBefore.push_back( arrayDimension ); |
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187 | |
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188 | hoist( arrayType->get_base() ); |
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189 | return; |
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190 | } |
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191 | } |
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192 | |
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193 | void HoistArrayDimension::premutate( FunctionDecl * ) { |
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194 | GuardValue( inFunction ); |
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195 | } |
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196 | |
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197 | void CtorDtor::generateCtorDtor( std::list< Declaration * > & translationUnit ) { |
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198 | PassVisitor<CtorDtor> ctordtor; |
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199 | acceptAll( translationUnit, ctordtor ); |
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200 | } |
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201 | |
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202 | bool CtorDtor::isManaged( Type * type ) const { |
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203 | // references are never constructed |
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204 | if ( dynamic_cast< ReferenceType * >( type ) ) return false; |
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205 | // need to clear and reset qualifiers when determining if a type is managed |
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206 | ValueGuard< Type::Qualifiers > qualifiers( type->get_qualifiers() ); |
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207 | type->get_qualifiers() = Type::Qualifiers(); |
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208 | if ( TupleType * tupleType = dynamic_cast< TupleType * > ( type ) ) { |
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209 | // tuple is also managed if any of its components are managed |
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210 | if ( std::any_of( tupleType->types.begin(), tupleType->types.end(), [&](Type * type) { return isManaged( type ); }) ) { |
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211 | return true; |
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212 | } |
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213 | } |
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214 | // 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) |
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215 | return managedTypes.find( SymTab::Mangler::mangle( type ) ) != managedTypes.end() || GenPoly::isPolyType( type ); |
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216 | } |
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217 | |
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218 | bool CtorDtor::isManaged( ObjectDecl * objDecl ) const { |
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219 | Type * type = objDecl->get_type(); |
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220 | while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) { |
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221 | type = at->get_base(); |
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222 | } |
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223 | return isManaged( type ); |
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224 | } |
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225 | |
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226 | void CtorDtor::handleDWT( DeclarationWithType * dwt ) { |
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227 | // if this function is a user-defined constructor or destructor, mark down the type as "managed" |
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228 | if ( ! LinkageSpec::isOverridable( dwt->get_linkage() ) && CodeGen::isCtorDtor( dwt->get_name() ) ) { |
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229 | std::list< DeclarationWithType * > & params = GenPoly::getFunctionType( dwt->get_type() )->get_parameters(); |
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230 | assert( ! params.empty() ); |
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231 | Type * type = InitTweak::getPointerBase( params.front()->get_type() ); |
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232 | assert( type ); |
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233 | managedTypes.insert( SymTab::Mangler::mangle( type ) ); |
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234 | } |
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235 | } |
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236 | |
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237 | ImplicitCtorDtorStmt * genCtorDtor( const std::string & fname, ObjectDecl * objDecl, Expression * arg ) { |
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238 | // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor |
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239 | assertf( objDecl, "genCtorDtor passed null objDecl" ); |
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240 | std::list< Statement * > stmts; |
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241 | InitExpander srcParam( maybeClone( arg ) ); |
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242 | SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), fname, back_inserter( stmts ), objDecl ); |
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243 | assert( stmts.size() <= 1 ); |
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244 | return stmts.size() == 1 ? strict_dynamic_cast< ImplicitCtorDtorStmt * >( stmts.front() ) : nullptr; |
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245 | } |
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246 | |
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247 | ConstructorInit * genCtorInit( ObjectDecl * objDecl ) { |
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248 | // call into genImplicitCall from Autogen.h to generate calls to ctor/dtor |
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249 | // for each constructable object |
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250 | std::list< Statement * > ctor; |
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251 | std::list< Statement * > dtor; |
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252 | |
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253 | InitExpander srcParam( objDecl->get_init() ); |
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254 | InitExpander nullParam( (Initializer *)NULL ); |
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255 | SymTab::genImplicitCall( srcParam, new VariableExpr( objDecl ), "?{}", back_inserter( ctor ), objDecl ); |
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256 | SymTab::genImplicitCall( nullParam, new VariableExpr( objDecl ), "^?{}", front_inserter( dtor ), objDecl, false ); |
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257 | |
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258 | // Currently genImplicitCall produces a single Statement - a CompoundStmt |
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259 | // which wraps everything that needs to happen. As such, it's technically |
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260 | // possible to use a Statement ** in the above calls, but this is inherently |
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261 | // unsafe, so instead we take the slightly less efficient route, but will be |
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262 | // immediately informed if somehow the above assumption is broken. In this case, |
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263 | // we could always wrap the list of statements at this point with a CompoundStmt, |
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264 | // but it seems reasonable at the moment for this to be done by genImplicitCall |
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265 | // itself. It is possible that genImplicitCall produces no statements (e.g. if |
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266 | // an array type does not have a dimension). In this case, it's fine to ignore |
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267 | // the object for the purposes of construction. |
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268 | assert( ctor.size() == dtor.size() && ctor.size() <= 1 ); |
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269 | if ( ctor.size() == 1 ) { |
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270 | // need to remember init expression, in case no ctors exist |
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271 | // if ctor does exist, want to use ctor expression instead of init |
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272 | // push this decision to the resolver |
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273 | assert( dynamic_cast< ImplicitCtorDtorStmt * > ( ctor.front() ) && dynamic_cast< ImplicitCtorDtorStmt * > ( dtor.front() ) ); |
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274 | return new ConstructorInit( ctor.front(), dtor.front(), objDecl->get_init() ); |
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275 | } |
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276 | return nullptr; |
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277 | } |
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278 | |
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279 | void CtorDtor::previsit( ObjectDecl * objDecl ) { |
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280 | handleDWT( objDecl ); |
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281 | // hands off if @=, extern, builtin, etc. |
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282 | // even if unmanaged, try to construct global or static if initializer is not constexpr, since this is not legal C |
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283 | if ( tryConstruct( objDecl ) && ( isManaged( objDecl ) || ((! inFunction || objDecl->get_storageClasses().is_static ) && ! isConstExpr( objDecl->get_init() ) ) ) ) { |
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284 | // constructed objects cannot be designated |
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285 | 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 ); |
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286 | // constructed objects should not have initializers nested too deeply |
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287 | if ( ! checkInitDepth( objDecl ) ) throw SemanticError( "Managed object's initializer is too deep ", objDecl ); |
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288 | |
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289 | objDecl->set_init( genCtorInit( objDecl ) ); |
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290 | } |
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291 | } |
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292 | |
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293 | void CtorDtor::previsit( FunctionDecl *functionDecl ) { |
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294 | visit_children = false; // do not try and construct parameters or forall parameters |
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295 | GuardValue( inFunction ); |
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296 | inFunction = true; |
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297 | |
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298 | handleDWT( functionDecl ); |
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299 | |
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300 | GuardScope( managedTypes ); |
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301 | // go through assertions and recursively add seen ctor/dtors |
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302 | for ( auto & tyDecl : functionDecl->get_functionType()->get_forall() ) { |
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303 | for ( DeclarationWithType *& assertion : tyDecl->get_assertions() ) { |
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304 | handleDWT( assertion ); |
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305 | } |
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306 | } |
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307 | |
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308 | maybeAccept( functionDecl->get_statements(), *visitor ); |
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309 | } |
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310 | |
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311 | void CtorDtor::previsit( StructDecl *aggregateDecl ) { |
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312 | visit_children = false; // do not try to construct and destruct aggregate members |
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313 | |
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314 | // don't construct members, but need to take note if there is a managed member, |
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315 | // because that means that this type is also managed |
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316 | for ( Declaration * member : aggregateDecl->get_members() ) { |
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317 | if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) { |
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318 | if ( isManaged( field ) ) { |
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319 | StructInstType inst( Type::Qualifiers(), aggregateDecl ); |
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320 | managedTypes.insert( SymTab::Mangler::mangle( &inst ) ); |
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321 | break; |
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322 | } |
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323 | } |
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324 | } |
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325 | } |
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326 | |
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327 | void CtorDtor::previsit( CompoundStmt * ) { |
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328 | GuardScope( managedTypes ); |
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329 | } |
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330 | } // namespace InitTweak |
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331 | |
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332 | // Local Variables: // |
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333 | // tab-width: 4 // |
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334 | // mode: c++ // |
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335 | // compile-command: "make install" // |
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336 | // End: // |
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