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 | // LvalueNew.cpp -- Clean up lvalues and remove references.
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8 | //
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9 | // Author : Andrew Beach
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10 | // Created On : Thu Sep 15 14:08:00 2022
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11 | // Last Modified By : Andrew Beach
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12 | // Last Modified On : Wed Oct 6 9:59:00 2022
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13 | // Update Count : 0
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14 | //
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15 |
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16 | #include "Lvalue.h"
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17 |
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18 | #include <set>
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19 | #include <iostream>
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20 |
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21 | #include "AST/Copy.hpp" // for deepCopy
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22 | #include "AST/Expr.hpp"
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23 | #include "AST/Inspect.hpp"
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24 | #include "AST/LinkageSpec.hpp" // for Linkage
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25 | #include "AST/Pass.hpp"
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26 | #include "Common/SemanticError.h" // for SemanticWarning
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27 | #include "Common/ToString.hpp" // for toCString
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28 | #include "Common/UniqueName.h" // for UniqueName
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29 | #include "GenPoly/GenPoly.h" // for genFunctionType
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30 | #include "ResolvExpr/typeops.h" // for typesCompatible
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31 | #include "ResolvExpr/Unify.h" // for unify
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32 |
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33 | #if 0
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34 | #define PRINT(x) x
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35 | #else
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36 | #define PRINT(x)
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37 | #endif
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38 |
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39 | namespace GenPoly {
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40 |
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41 | namespace {
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42 |
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43 | /// Intrinsic functions that return references now instead return lvalues.
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44 | struct FixIntrinsicResults final : public ast::WithGuards {
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45 | enum {
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46 | NoSkip,
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47 | Skip,
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48 | SkipInProgress,
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49 | } skip = NoSkip;
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50 |
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51 | void previsit( ast::AsmExpr const * ) {
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52 | GuardValue( skip ) = Skip;
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53 | }
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54 | void previsit( ast::ApplicationExpr const * ) {
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55 | GuardValue( skip ) = (skip == Skip) ? SkipInProgress : NoSkip;
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56 | }
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57 |
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58 | ast::Expr const * postvisit( ast::ApplicationExpr const * expr );
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59 | void previsit( ast::FunctionDecl const * decl );
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60 | bool inIntrinsic = false;
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61 | };
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62 |
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63 | /// Add de-references around address-of operations on reference types.
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64 | struct AddressRef final :
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65 | public ast::WithConstTranslationUnit,
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66 | public ast::WithGuards,
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67 | public ast::WithShortCircuiting,
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68 | public ast::WithVisitorRef<AddressRef> {
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69 | void previsit( ast::AddressExpr const * expr );
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70 | ast::Expr const * postvisit( ast::AddressExpr const * expr );
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71 | void previsit( ast::Expr const * expr );
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72 | ast::ApplicationExpr const * previsit( ast::ApplicationExpr const * expr );
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73 | void previsit( ast::SingleInit const * init );
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74 |
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75 | void handleNonAddr( ast::Expr const * expr );
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76 |
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77 | bool first = true;
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78 | bool current = false;
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79 | bool addCast = false;
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80 | int refDepth = 0;
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81 | };
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82 |
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83 | /// Handles casts between references and pointers,
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84 | /// creating temporaries for the conversion.
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85 | struct ReferenceConversions final :
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86 | public ast::WithConstTranslationUnit,
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87 | public ast::WithGuards, public ast::WithStmtsToAdd<> {
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88 | ast::Expr const * postvisit( ast::CastExpr const * expr );
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89 | ast::Expr const * postvisit( ast::AddressExpr const * expr );
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90 | };
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91 |
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92 | /// Intrinsic functions that take reference parameters don't actually do.
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93 | /// Their reference arguments must be implicity dereferenced.
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94 | /// TODO Also appears to contain redundent code with AddressRef
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95 | struct FixIntrinsicArgs final :
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96 | public ast::WithConstTranslationUnit {
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97 | ast::Expr const * postvisit( ast::ApplicationExpr const * expr );
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98 | };
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99 |
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100 | /// Removes redundant &* / *& patterns that may be generated.
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101 | struct CollapseAddressDeref final {
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102 | ast::Expr const * postvisit( ast::AddressExpr const * expr );
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103 | ast::Expr const * postvisit( ast::ApplicationExpr const * expr );
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104 | };
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105 |
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106 | /// GCC-like Generalized Lvalues (which have since been removed from GCC).
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107 | /// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
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108 | /// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
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109 | struct GeneralizedLvalue final :
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110 | public ast::WithVisitorRef<GeneralizedLvalue> {
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111 | ast::Expr const * postvisit( ast::AddressExpr const * expr );
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112 | ast::Expr const * postvisit( ast::MemberExpr const * expr );
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113 |
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114 | template<typename Node, typename Func>
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115 | ast::Expr const * applyTransformation(
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116 | Node const * expr, ast::ptr<ast::Expr> Node::*field, Func mkExpr );
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117 | };
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118 |
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119 | /// Replace all reference types with pointer types.
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120 | struct ReferenceTypeElimination final {
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121 | ast::Type const * postvisit( ast::ReferenceType const * type );
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122 | };
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123 |
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124 | /// True for intrinsic function calls that return an lvalue in C.
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125 | bool isIntrinsicReference( ast::Expr const * expr ) {
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126 | // The known intrinsic-reference prelude functions.
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127 | static std::set<std::string> const lvalueFunctions = { "*?", "?[?]" };
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128 | if ( auto untyped = dynamic_cast<ast::UntypedExpr const *>( expr ) ) {
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129 | std::string fname = ast::getFunctionName( untyped );
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130 | return lvalueFunctions.count( fname );
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131 | } else if ( auto app = dynamic_cast<ast::ApplicationExpr const *>( expr ) ) {
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132 | if ( auto func = ast::getFunction( app ) ) {
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133 | return func->linkage == ast::Linkage::Intrinsic
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134 | && lvalueFunctions.count( func->name );
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135 | }
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136 | }
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137 | return false;
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138 | }
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139 |
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140 | // A maybe typed variant of the createDeref function (only UntypedExpr).
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141 | ast::Expr * mkDeref(
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142 | ast::TranslationGlobal const & global, ast::Expr const * arg ) {
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143 | if ( global.dereference ) {
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144 | // Note: Reference depth can be arbitrarily deep here,
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145 | // so peel off the outermost pointer/reference, not just
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146 | // pointer because they are effecitvely equivalent in this pass
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147 | ast::VariableExpr * deref = new ast::VariableExpr(
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148 | arg->location, global.dereference );
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149 | deref->result = new ast::PointerType( deref->result );
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150 | ast::Type const * base = ast::getPointerBase( arg->result );
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151 | assertf( base, "expected pointer type in dereference (type was %s)", toString( arg->result ).c_str() );
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152 | ast::ApplicationExpr * ret =
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153 | new ast::ApplicationExpr( arg->location, deref, { arg } );
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154 | ret->result = ast::deepCopy( base );
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155 | return ret;
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156 | } else {
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157 | return ast::UntypedExpr::createDeref( arg->location, arg );
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158 | }
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159 | }
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160 |
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161 | ast::Expr const * FixIntrinsicResults::postvisit(
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162 | ast::ApplicationExpr const * expr ) {
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163 | if ( skip == SkipInProgress || !isIntrinsicReference( expr ) ) {
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164 | return expr;
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165 | }
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166 | // Eliminate reference types from intrinsic applications
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167 | // now they return lvalues.
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168 | ast::ptr<ast::ReferenceType> result =
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169 | expr->result.strict_as<ast::ReferenceType>();
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170 | expr = ast::mutate_field( expr, &ast::ApplicationExpr::result,
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171 | ast::deepCopy( result->base ) );
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172 | if ( inIntrinsic ) {
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173 | return expr;
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174 | }
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175 | // When not in an intrinsic function, add a cast to don't add cast when
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176 | // in an intrinsic function, since they already have the cast.
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177 | auto * ret = new ast::CastExpr( expr->location, expr, result.get() );
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178 | ret->env = expr->env;
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179 | return ret;
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180 | }
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181 |
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182 | void FixIntrinsicResults::previsit( ast::FunctionDecl const * decl ) {
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183 | GuardValue( inIntrinsic ) = decl->linkage == ast::Linkage::Intrinsic;
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184 | }
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185 |
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186 | void AddressRef::previsit( ast::AddressExpr const * ) {
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187 | // Is this the first address-of in the chain?
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188 | GuardValue( current ) = first;
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189 | // Later references will not be for next address-of to be first in chain.
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190 | GuardValue( first ) = false;
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191 | // If is the outermost address-of in a chain:
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192 | if ( current ) {
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193 | // Set depth to 0 so that postvisit can
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194 | // find the innermost address-of easily.
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195 | GuardValue( refDepth ) = 0;
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196 | }
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197 | }
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198 |
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199 | ast::Expr const * AddressRef::postvisit( ast::AddressExpr const * expr ) {
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200 | PRINT( std::cerr << "addr ref at " << expr << std::endl; )
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201 | if ( 0 == refDepth ) {
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202 | PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
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203 | // Is this the innermost address-of in a chain? record depth D.
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204 | if ( isIntrinsicReference( expr->arg ) ) {
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205 | assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( expr->arg ) );
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206 | } else {
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207 | // try to avoid ?[?]
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208 | // TODO is this condition still necessary? intrinsicReferences
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209 | // should have a cast around them at this point, so I don't think
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210 | // this condition ever fires.
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211 | refDepth = expr->arg->result->referenceDepth();
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212 | PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
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213 | }
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214 | }
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215 | if ( current ) {
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216 | PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
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217 | ast::Expr const * ret = expr;
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218 | while ( refDepth ) {
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219 | // Add one dereference for each address-of in the chain.
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220 | ret = mkDeref( transUnit().global, ret );
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221 | --refDepth;
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222 | }
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223 |
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224 | // if addrExpr depth is 0, then the result is a pointer because the
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225 | // arg was depth 1 and not lvalue. This means the dereference result
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226 | // is not a reference, is lvalue, and one less pointer depth than the
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227 | // addrExpr. Thus the cast is meaningless.
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228 | // TODO: One thing to double check is whether it is possible for the
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229 | // types to differ outside of the single pointer level (i.e. can the
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230 | // base type of addrExpr differ from the type of addrExpr-arg?). If
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231 | // so then the cast might need to be added, conditional on a more
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232 | // sophisticated check.
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233 | if ( addCast && 0 != expr->result->referenceDepth() ) {
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234 | PRINT( std::cerr << "adding cast to " << expr->result << std::endl; )
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235 | return new ast::CastExpr( expr->location,
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236 | ret, ast::deepCopy( expr->result ) );
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237 | }
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238 | return ret;
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239 | }
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240 | PRINT( std::cerr << "not current..." << std::endl; )
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241 | return expr;
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242 | }
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243 |
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244 | void AddressRef::previsit( ast::Expr const * expr ) {
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245 | handleNonAddr( expr );
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246 | GuardValue( addCast ) = false;
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247 | }
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248 |
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249 | // So we want to skip traversing to the head?
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250 | ast::ApplicationExpr const * AddressRef::previsit(
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251 | ast::ApplicationExpr const * expr ) {
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252 | visit_children = false;
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253 | GuardValue( addCast );
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254 | handleNonAddr( expr );
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255 | auto mutExpr = ast::mutate( expr );
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256 | for ( ast::ptr<ast::Expr> & arg : mutExpr->args ) {
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257 | addCast = true;
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258 | arg = arg->accept( *visitor );
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259 | }
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260 | return mutExpr;
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261 | }
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262 |
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263 | void AddressRef::previsit( ast::SingleInit const * ) {
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264 | // Each initialization context with address-of requires a cast.
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265 | GuardValue( addCast ) = true;
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266 | }
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267 |
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268 | // idea: &&&E: get outer &, inner &
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269 | // at inner &, record depth D of reference type of argument of &.
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270 | // at auter &, add D derefs.
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271 | void AddressRef::handleNonAddr( ast::Expr const * ) {
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272 | // non-address-of: reset status variables:
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273 | // * current expr is NOT the first address-of expr in an address-of chain.
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274 | // * next seen address-of expr IS the first in the chain.
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275 | GuardValue( current ) = false;
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276 | GuardValue( first ) = true;
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277 | }
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278 |
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279 | ast::Expr const * ReferenceConversions::postvisit(
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280 | ast::CastExpr const * expr ) {
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281 | // TODO: Is it possible to convert directly between reference types with
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282 | // a different base. e.g.
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283 | // int x;
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284 | // (double&)x;
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285 | // At the moment, I (who?) am working off of the assumption that this is
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286 | // illegal, thus the cast becomes redundant after this pass, so trash the
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287 | // cast altogether. If that changes, care must be taken to insert the
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288 | // correct pointer casts in the right places.
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289 |
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290 | // Note: reference depth difference is the determining factor in what
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291 | // code is run, rather than whether something is reference type or not,
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292 | // since conversion still needs to occur when both types are references
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293 | // that differ in depth.
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294 | ast::Type const * dstType = expr->result.get();
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295 | ast::Type const * srcType = expr->arg->result.get();
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296 | assertf( dstType, "Cast to no type in: %s", toCString( expr ) );
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297 | assertf( srcType, "Cast from no type in: %s", toCString( expr ) );
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298 | int dstDepth = dstType->referenceDepth();
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299 | int srcDepth = srcType->referenceDepth();
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300 | int diff = dstDepth - srcDepth;
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301 |
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302 | if ( 0 < diff && !expr->arg->get_lvalue() ) {
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303 | // rvalue to reference conversion -- introduce temporary
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304 | // know that reference depth of cast argument is 0
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305 | // (int &&&)3;
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306 | // becomes
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307 | // int __ref_tmp_0 = 3;
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308 | // int & __ref_tmp_1 = &__ref_tmp_0;
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309 | // int && __ref_tmp_2 = &__ref_tmp_1;
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310 | // &__ref_tmp_2;
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311 | // The last & comes from the remaining reference conversion code.
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312 | SemanticWarning( expr->arg->location,
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313 | Warning::RvalueToReferenceConversion, toCString( expr->arg ) );
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314 |
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315 | static UniqueName tmpNamer( "__ref_tmp_" );
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316 | ast::ObjectDecl * tmp = new ast::ObjectDecl( expr->arg->location,
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317 | tmpNamer.newName(),
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318 | ast::deepCopy( expr->arg->result ),
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319 | new ast::SingleInit( expr->arg->location, expr->arg ) );
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320 | PRINT( std::cerr << "make tmp: " << tmp << std::endl; )
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321 | stmtsToAddBefore.push_back( new ast::DeclStmt( tmp->location, tmp ) );
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322 | for ( int i = 0 ; i < dstDepth - 1 ; ++i ) {
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323 | ast::ObjectDecl * newTmp = new ast::ObjectDecl( tmp->location,
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324 | tmpNamer.newName(),
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325 | new ast::ReferenceType( ast::deepCopy( tmp->type ) ),
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326 | new ast::SingleInit( tmp->location,
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327 | new ast::AddressExpr( tmp->location,
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328 | new ast::VariableExpr( tmp->location, tmp ) ) ) );
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329 | PRINT( std::cerr << "make tmp: " << i << ": " << newTmp << std::endl; )
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330 | stmtsToAddBefore.push_back(
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331 | new ast::DeclStmt( newTmp->location, newTmp ) );
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332 | tmp = newTmp;
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333 | }
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334 | // Update diff so that remaining code works out correctly.
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335 | expr = ast::mutate_field( expr, &ast::CastExpr::arg,
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336 | new ast::VariableExpr( tmp->location, tmp ) );
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337 | PRINT( std::cerr << "update cast to: " << expr << std::endl; )
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338 | srcType = expr->arg->result;
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339 | srcDepth = srcType->referenceDepth();
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340 | diff = dstDepth - srcDepth;
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341 | assert( 1 == diff );
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342 | }
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343 |
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344 | // Handle conversion between different depths.
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345 | PRINT(
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346 | if ( dstDepth || srcDepth ) {
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347 | std::cerr << "dstType: " << dstType << " / srcType: " << srcType << '\n';
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348 | std::cerr << "depth: " << dstDepth << " / " << srcDepth << std::endl;
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349 | }
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350 | )
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351 | // Conversion to type with more depth/more references.
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352 | // Add address-of for each level of difference.
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353 | if ( 0 < diff ) {
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354 | ast::Expr * ret = ast::mutate( expr->arg.get() );
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355 | for ( int i = 0 ; i < diff ; ++i ) {
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356 | ret = new ast::AddressExpr( ret->location, ret );
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357 | }
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358 | if ( expr->arg->get_lvalue() &&
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359 | !ResolvExpr::typesCompatible(
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360 | srcType,
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361 | strict_dynamic_cast<ast::ReferenceType const *>( dstType )->base,
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362 | ast::SymbolTable() ) ) {
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363 | // Must keep cast if cast-to type is different from the actual type.
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364 | return ast::mutate_field( expr, &ast::CastExpr::arg, ret );
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365 | }
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366 | ret->env = expr->env;
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367 | ret->result = expr->result;
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368 | return ret;
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369 | // Conversion to type with less depth/fewer references.
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370 | // Add dereferences for each level of difference.
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371 | } else if ( diff < 0 ) {
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372 | ast::Expr * ret = ast::mutate( expr->arg.get() );
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373 | for ( int i = 0 ; i < -diff ; ++i ) {
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374 | ret = mkDeref( transUnit().global, ret );
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375 | }
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376 | // Must keep cast if types are different.
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377 | if ( !ResolvExpr::typesCompatibleIgnoreQualifiers(
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378 | dstType->stripReferences(),
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379 | srcType->stripReferences(),
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380 | ast::SymbolTable() ) ) {
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381 | return ast::mutate_field( expr, &ast::CastExpr::arg, ret );
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382 | }
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383 | ret->env = expr->env;
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384 | ret->result = expr->result;
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385 | // The result must be an lvalue.
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386 | assert( ret->get_lvalue() );
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387 | return ret;
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388 | // Conversion with the same depth.
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389 | } else {
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390 | assert( 0 == diff );
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391 | // Remove useless generated casts.
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392 | if ( expr->isGenerated &&
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393 | ResolvExpr::typesCompatible(
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394 | expr->result,
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395 | expr->arg->result, ast::SymbolTable() ) ) {
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396 | PRINT(
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397 | std::cerr << "types are compatible, removing cast: " << expr << '\n';
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398 | std::cerr << "-- " << expr->result << '\n';
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399 | std::cerr << "-- " << expr->arg->result << std::endl;
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400 | )
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401 | return ast::mutate_field( expr->arg.get(),
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402 | &ast::Expr::env, expr->env.get() );
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403 | }
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404 | return expr;
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405 | }
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406 | }
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407 |
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408 | ast::Expr const * ReferenceConversions::postvisit(
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409 | ast::AddressExpr const * expr ) {
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410 | // Inner expression may have been lvalue to reference conversion, which
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411 | // becomes an address expression. In this case, remove the outer address
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412 | // expression and return the argument.
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413 | // TODO: It's possible that this might catch too much and require a more
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414 | // sophisticated check. TODO What check are we talking about here?
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415 | return expr;
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416 | }
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417 |
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418 | ast::Expr const * FixIntrinsicArgs::postvisit(
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419 | ast::ApplicationExpr const * expr ) {
|
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420 | // Intrinsic functions don't really take reference-typed parameters,
|
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421 | // so they require an implicit dereference on their arguments.
|
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422 | auto function = ast::getFunction( expr );
|
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423 | if ( function == nullptr ) {
|
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424 | return expr;
|
---|
425 | }
|
---|
426 |
|
---|
427 | ast::FunctionType const * ftype = GenPoly::getFunctionType( function->get_type() );
|
---|
428 | assertf( ftype, "Function declaration does not have function type." );
|
---|
429 | // Can be of different lengths only when function is variadic.
|
---|
430 | assertf( ftype->params.size() == expr->args.size() || ftype->isVarArgs,
|
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431 | "ApplicationExpr args do not match formal parameter type." );
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432 | assertf( ftype->params.size() <= expr->args.size(),
|
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433 | "Cannot have more parameters than arguments." );
|
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434 |
|
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435 | unsigned int i = 0;
|
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436 | unsigned int const end = ftype->params.size();
|
---|
437 |
|
---|
438 | // This is used to make sure we get a zip on shortests.
|
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439 | if ( end == i ) return expr;
|
---|
440 |
|
---|
441 | // This mutate could be redundent, but it is simpler this way.
|
---|
442 | auto mutExpr = ast::mutate( expr );
|
---|
443 |
|
---|
444 | for ( auto pair : unsafe_group_iterate( mutExpr->args, ftype->params ) ) {
|
---|
445 | ast::ptr<ast::Expr> & arg = std::get<0>( pair );
|
---|
446 | ast::ptr<ast::Type> const & formal = std::get<1>( pair );
|
---|
447 | PRINT(
|
---|
448 | std::cerr << "pair<0>: " << arg.get() << std::endl;
|
---|
449 | std::cerr << " -- " << arg->result << std::endl;
|
---|
450 | std::cerr << "pair<1>: " << formal << std::endl;
|
---|
451 | )
|
---|
452 | //if ( dynamic_cast<ast::ReferenceType const *>( formal.get() ) ) {
|
---|
453 | if ( formal.as<ast::ReferenceType>() ) {
|
---|
454 | PRINT( std::cerr << "===formal is reference" << std::endl; )
|
---|
455 | // TODO: It's likely that the second condition should be
|
---|
456 | // `... && ! isIntrinsicReference( arg )`, but this requires
|
---|
457 | // investigation.
|
---|
458 |
|
---|
459 | if ( ast::Linkage::Intrinsic != function->linkage
|
---|
460 | && isIntrinsicReference( arg ) ) {
|
---|
461 | // Needed for definition of prelude functions, etc.
|
---|
462 | // If argument is dereference or array subscript, the result
|
---|
463 | // isn't REALLY a reference, but non-intrinsic functions
|
---|
464 | // expect a reference: take address
|
---|
465 |
|
---|
466 | // TODO: OK, so this should be cut?!
|
---|
467 | // NODE: Previously, this condition fixed
|
---|
468 | // void f(int *&);
|
---|
469 | // int & x = ...;
|
---|
470 | // f(&x);
|
---|
471 | // But now this is taken care of by a reference cast added by
|
---|
472 | // AddressRef. Need to find a new example or remove this
|
---|
473 | // branch.
|
---|
474 | PRINT(
|
---|
475 | std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
|
---|
476 | )
|
---|
477 | arg = new ast::AddressExpr( arg->location, arg );
|
---|
478 | } else if ( ast::Linkage::Intrinsic == function->linkage
|
---|
479 | && arg->result->referenceDepth() != 0 ) {
|
---|
480 | // Argument is a 'real' reference, but function expects a C
|
---|
481 | // lvalue: Add a dereference to the reference-typed argument.
|
---|
482 | PRINT(
|
---|
483 | std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
|
---|
484 | )
|
---|
485 | ast::Type const * base = ast::getPointerBase( arg->result );
|
---|
486 | assertf( base, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
|
---|
487 | ast::PointerType * ptr = new ast::PointerType( ast::deepCopy( base ) );
|
---|
488 | arg = ast::mutate_field( arg.get(),
|
---|
489 | &ast::ApplicationExpr::result, ptr );
|
---|
490 | arg = mkDeref( transUnit().global, arg );
|
---|
491 | }
|
---|
492 | }
|
---|
493 | ++i;
|
---|
494 | if ( end == i ) break;
|
---|
495 | }
|
---|
496 | return mutExpr;
|
---|
497 | }
|
---|
498 |
|
---|
499 | ast::Expr const * CollapseAddressDeref::postvisit(
|
---|
500 | ast::AddressExpr const * expr ) {
|
---|
501 | ast::Expr const * arg = expr->arg;
|
---|
502 | if ( isIntrinsicReference( arg ) ) {
|
---|
503 | std::string fname = ast::getFunctionName( arg );
|
---|
504 | if ( fname == "*?" ) {
|
---|
505 | ast::Expr const * arg0 = ast::getCallArg( arg, 0 );
|
---|
506 | ast::Expr * ret = ast::mutate( arg0 );
|
---|
507 | ret->env = expr->env;
|
---|
508 | return ret;
|
---|
509 | }
|
---|
510 | } else if ( auto cast = dynamic_cast<ast::CastExpr const *>( arg ) ) {
|
---|
511 | // Need to move cast to pointer type out a level since address of
|
---|
512 | // pointer is not valid C code (can be introduced in prior passes,
|
---|
513 | // e.g., InstantiateGeneric)
|
---|
514 | if ( ast::getPointerBase( cast->result ) ) {
|
---|
515 | auto mutExpr = ast::mutate( expr );
|
---|
516 | auto mutCast = strict_dynamic_cast<ast::CastExpr *>(
|
---|
517 | ast::mutate( mutExpr->arg.release() ) );
|
---|
518 | mutExpr->arg = mutCast->arg;
|
---|
519 | mutCast->arg = mutExpr;
|
---|
520 | mutCast->result = new ast::PointerType( mutCast->result );
|
---|
521 | return mutCast;
|
---|
522 | }
|
---|
523 | }
|
---|
524 | return expr;
|
---|
525 | }
|
---|
526 |
|
---|
527 | ast::Expr const * CollapseAddressDeref::postvisit(
|
---|
528 | ast::ApplicationExpr const * expr ) {
|
---|
529 | if ( isIntrinsicReference( expr ) ) {
|
---|
530 | std::string fname = ast::getFunctionName( expr );
|
---|
531 | if ( fname == "*?" ) {
|
---|
532 | assert( 1 == expr->args.size() );
|
---|
533 | ast::Expr const * arg = ast::getCallArg( expr, 0 );
|
---|
534 | // xxx - this isn't right, because it can remove casts that
|
---|
535 | // should be there...
|
---|
536 | // while ( auto cast = dynamic_cast< ast::CastExpr const * >( arg ) ) {
|
---|
537 | // arg = cast->arg;
|
---|
538 | // }
|
---|
539 | if ( auto addr = dynamic_cast<ast::AddressExpr const *>( arg ) ) {
|
---|
540 | return ast::mutate_field( addr->arg.get(),
|
---|
541 | &ast::Expr::env, expr->env.get() );
|
---|
542 | }
|
---|
543 | }
|
---|
544 | }
|
---|
545 | return expr;
|
---|
546 | }
|
---|
547 |
|
---|
548 | ast::Expr const * GeneralizedLvalue::postvisit(
|
---|
549 | ast::AddressExpr const * expr ) {
|
---|
550 | return applyTransformation( expr, &ast::AddressExpr::arg,
|
---|
551 | []( ast::Expr const * arg ) {
|
---|
552 | return new ast::AddressExpr( arg->location, arg );
|
---|
553 | }
|
---|
554 | );
|
---|
555 | }
|
---|
556 |
|
---|
557 | ast::Expr const * GeneralizedLvalue::postvisit(
|
---|
558 | ast::MemberExpr const * expr ) {
|
---|
559 | return applyTransformation( expr, &ast::MemberExpr::aggregate,
|
---|
560 | [expr]( ast::Expr const * aggr ) {
|
---|
561 | return new ast::MemberExpr( aggr->location, expr->member, aggr );
|
---|
562 | }
|
---|
563 | );
|
---|
564 | }
|
---|
565 |
|
---|
566 | template<typename Node, typename Func>
|
---|
567 | ast::Expr const * GeneralizedLvalue::applyTransformation(
|
---|
568 | Node const * expr, ast::ptr<ast::Expr> Node::*field, Func mkExpr ) {
|
---|
569 | ast::ptr<ast::Expr> const & arg = expr->*field;
|
---|
570 | if ( auto commaArg = arg.as<ast::CommaExpr>() ) {
|
---|
571 | ast::Expr const * arg1 = ast::deepCopy( commaArg->arg1 );
|
---|
572 | ast::Expr const * arg2 = ast::deepCopy( commaArg->arg2 );
|
---|
573 | ast::Expr const * ret = new ast::CommaExpr(
|
---|
574 | commaArg->location, arg1, mkExpr( arg2 )->accept( *visitor ) );
|
---|
575 | return ret;
|
---|
576 | } else if ( auto condArg = arg.as<ast::ConditionalExpr>() ) {
|
---|
577 | ast::Expr const * arg1 = ast::deepCopy( condArg->arg1 );
|
---|
578 | ast::Expr const * arg2 = ast::deepCopy( condArg->arg2 );
|
---|
579 | ast::Expr const * arg3 = ast::deepCopy( condArg->arg3 );
|
---|
580 | ast::ConditionalExpr * ret = new ast::ConditionalExpr(
|
---|
581 | condArg->location, arg1, mkExpr( arg2 )->accept( *visitor ),
|
---|
582 | mkExpr( arg3 )->accept( *visitor ) );
|
---|
583 |
|
---|
584 | // Conditional expr type may not be either of the arguments,
|
---|
585 | // so unify to get the result.
|
---|
586 | // TODO: Maybe I could create a wrapper for this.
|
---|
587 | ast::ptr<ast::Type> common = nullptr;
|
---|
588 | ast::TypeEnvironment newEnv;
|
---|
589 | ast::AssertionSet needAssertions, haveAssertions;
|
---|
590 | ast::OpenVarSet openVars;
|
---|
591 | ResolvExpr::unify( ret->arg2->result, ret->arg3->result, newEnv,
|
---|
592 | needAssertions, haveAssertions, openVars,
|
---|
593 | ast::SymbolTable(), common );
|
---|
594 | ret->result = common ? common : ast::deepCopy( ret->arg2->result );
|
---|
595 | return ret;
|
---|
596 | }
|
---|
597 | return expr;
|
---|
598 | }
|
---|
599 |
|
---|
600 | ast::Type const * ReferenceTypeElimination::postvisit(
|
---|
601 | ast::ReferenceType const * type ) {
|
---|
602 | return new ast::PointerType( type->base, type->qualifiers );
|
---|
603 | }
|
---|
604 |
|
---|
605 | } // namespace
|
---|
606 |
|
---|
607 | // Stored elsewhere (Lvalue2, initially false):
|
---|
608 | extern bool referencesEliminated;
|
---|
609 |
|
---|
610 | void convertLvalue( ast::TranslationUnit & translationUnit ) {
|
---|
611 | ast::Pass<FixIntrinsicResults>::run( translationUnit );
|
---|
612 | ast::Pass<AddressRef>::run( translationUnit );
|
---|
613 | ast::Pass<ReferenceConversions>::run( translationUnit );
|
---|
614 | ast::Pass<FixIntrinsicArgs>::run( translationUnit );
|
---|
615 | ast::Pass<CollapseAddressDeref>::run( translationUnit );
|
---|
616 | ast::Pass<GeneralizedLvalue>::run( translationUnit );
|
---|
617 | // Last because other passes need reference types to work.
|
---|
618 | ast::Pass<ReferenceTypeElimination>::run( translationUnit );
|
---|
619 | // From this point forward, nothing should create reference types.
|
---|
620 | referencesEliminated = true;
|
---|
621 | }
|
---|
622 |
|
---|
623 | ast::Expr const * generalizedLvalue( ast::Expr const * expr ) {
|
---|
624 | ast::Pass<GeneralizedLvalue> visitor;
|
---|
625 | return expr->accept( visitor );
|
---|
626 | }
|
---|
627 |
|
---|
628 | } // namespace GenPoly
|
---|
629 |
|
---|
630 | // Local Variables: //
|
---|
631 | // tab-width: 4 //
|
---|
632 | // mode: c++ //
|
---|
633 | // compile-command: "make install" //
|
---|
634 | // End: //
|
---|