| 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 | // ExceptTranslate.cpp -- Conversion of exception control flow structures. | 
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| 8 | // | 
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| 9 | // Author           : Andrew Beach | 
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| 10 | // Created On       : Mon Nov  8 11:53:00 2021 | 
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| 11 | // Last Modified By : Andrew Beach | 
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| 12 | // Last Modified On : Fri Mar 11 17:51:00 2022 | 
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| 13 | // Update Count     : 2 | 
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| 14 | // | 
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| 15 |  | 
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| 16 | #include "ExceptTranslate.h" | 
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| 17 |  | 
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| 18 | #include "AST/Expr.hpp" | 
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| 19 | #include "AST/Pass.hpp" | 
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| 20 | #include "AST/Stmt.hpp" | 
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| 21 | #include "AST/TranslationUnit.hpp" | 
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| 22 | #include "AST/DeclReplacer.hpp" | 
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| 23 |  | 
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| 24 | namespace ControlStruct { | 
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| 25 |  | 
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| 26 | namespace { | 
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| 27 |  | 
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| 28 | typedef std::list<ast::CatchClause*> CatchList; | 
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| 29 |  | 
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| 30 | void appendDeclStmt( ast::CompoundStmt * block, ast::DeclWithType * item ) { | 
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| 31 | block->push_back( new ast::DeclStmt( block->location, item ) ); | 
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| 32 | } | 
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| 33 |  | 
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| 34 | class TranslateThrowsCore final : public ast::WithGuards { | 
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| 35 | const ast::ObjectDecl * terminateHandlerExcept; | 
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| 36 | enum Context { NoHandler, TerHandler, ResHandler } currentContext; | 
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| 37 |  | 
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| 38 | const ast::Stmt * createEitherThrow( | 
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| 39 | const ast::ThrowStmt * throwStmt, const char * funcName ); | 
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| 40 | const ast::Stmt * createTerminateRethrow( const ast::ThrowStmt * ); | 
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| 41 |  | 
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| 42 | public: | 
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| 43 | TranslateThrowsCore() : | 
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| 44 | terminateHandlerExcept( nullptr ), currentContext( NoHandler ) | 
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| 45 | {} | 
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| 46 |  | 
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| 47 | void previsit( const ast::CatchClause * stmt ); | 
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| 48 | const ast::Stmt * postvisit( const ast::ThrowStmt * stmt ); | 
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| 49 | }; | 
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| 50 |  | 
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| 51 | const ast::Stmt * TranslateThrowsCore::createEitherThrow( | 
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| 52 | const ast::ThrowStmt * throwStmt, const char * funcName ) { | 
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| 53 | // `throwFunc`( `throwStmt->name` ); | 
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| 54 | ast::UntypedExpr * call = new ast::UntypedExpr( throwStmt->location, | 
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| 55 | new ast::NameExpr( throwStmt->location, funcName ) | 
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| 56 | ); | 
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| 57 | call->args.push_back( throwStmt->expr ); | 
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| 58 | return new ast::ExprStmt( throwStmt->location, call ); | 
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| 59 | } | 
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| 60 |  | 
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| 61 | ast::VariableExpr * varOf( const ast::DeclWithType * decl ) { | 
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| 62 | return new ast::VariableExpr( decl->location, decl ); | 
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| 63 | } | 
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| 64 |  | 
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| 65 | const ast::Stmt * TranslateThrowsCore::createTerminateRethrow( | 
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| 66 | const ast::ThrowStmt * stmt ) { | 
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| 67 | // { `terminate_handler_except` = 0p; __rethrow_terminate(); } | 
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| 68 | assert( nullptr == stmt->expr ); | 
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| 69 | assert( terminateHandlerExcept ); | 
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| 70 |  | 
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| 71 | ast::CompoundStmt * result = new ast::CompoundStmt( | 
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| 72 | stmt->location, {}, std::vector<ast::Label>( stmt->labels ) ); | 
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| 73 | result->push_back( new ast::ExprStmt( stmt->location, | 
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| 74 | ast::UntypedExpr::createAssign( | 
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| 75 | stmt->location, | 
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| 76 | varOf( terminateHandlerExcept ), | 
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| 77 | ast::ConstantExpr::null( | 
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| 78 | stmt->location, | 
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| 79 | terminateHandlerExcept->type | 
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| 80 | ) | 
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| 81 | ) | 
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| 82 | ) ); | 
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| 83 | result->push_back( new ast::ExprStmt( stmt->location, new ast::UntypedExpr( | 
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| 84 | stmt->location, | 
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| 85 | new ast::NameExpr( stmt->location, "__cfaehm_rethrow_terminate" ) | 
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| 86 | ) ) ); | 
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| 87 | return result; | 
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| 88 | } | 
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| 89 |  | 
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| 90 | void TranslateThrowsCore::previsit( const ast::CatchClause * stmt ) { | 
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| 91 | // Validate the statement's form. | 
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| 92 | const ast::ObjectDecl * decl = stmt->decl.as<ast::ObjectDecl>(); | 
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| 93 | // Also checking the type would be nice. | 
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| 94 | if ( !decl || !decl->type.as<ast::PointerType>() ) { | 
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| 95 | std::string kind = (ast::Terminate == stmt->kind) ? "catch" : "catchResume"; | 
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| 96 | SemanticError( stmt->location, kind + " must have pointer to an exception type" ); | 
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| 97 | } | 
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| 98 |  | 
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| 99 | // Track the handler context. | 
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| 100 | if ( ast::Terminate == stmt->kind ) { | 
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| 101 | GuardValue( currentContext ) = TerHandler; | 
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| 102 | GuardValue( terminateHandlerExcept ) = decl; | 
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| 103 | } else { | 
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| 104 | GuardValue( currentContext ) = ResHandler; | 
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| 105 | } | 
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| 106 | } | 
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| 107 |  | 
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| 108 | const ast::Stmt * TranslateThrowsCore::postvisit( | 
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| 109 | const ast::ThrowStmt * stmt ) { | 
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| 110 | // Ignoring ThrowStmt::target for now. | 
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| 111 | // Handle Termination (Raise, Reraise, Error): | 
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| 112 | if ( ast::Terminate == stmt->kind ) { | 
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| 113 | if ( stmt->expr ) { | 
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| 114 | return createEitherThrow( stmt, "$throw" ); | 
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| 115 | } else if ( TerHandler == currentContext ) { | 
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| 116 | return createTerminateRethrow( stmt ); | 
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| 117 | } else { | 
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| 118 | abort( "Invalid throw in %s at %i\n", | 
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| 119 | stmt->location.filename.c_str(), | 
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| 120 | stmt->location.first_line); | 
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| 121 | } | 
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| 122 | // Handle Resumption (Raise, Reraise, Error): | 
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| 123 | } else { | 
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| 124 | if ( stmt->expr ) { | 
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| 125 | return createEitherThrow( stmt, "$throwResume" ); | 
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| 126 | } else if ( ResHandler == currentContext ) { | 
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| 127 | // This has to be handled later. | 
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| 128 | return stmt; | 
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| 129 | } else { | 
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| 130 | abort( "Invalid throwResume in %s at %i\n", | 
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| 131 | stmt->location.filename.c_str(), | 
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| 132 | stmt->location.first_line); | 
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| 133 | } | 
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| 134 | } | 
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| 135 | } | 
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| 136 |  | 
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| 137 |  | 
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| 138 | class TryMutatorCore final { | 
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| 139 | // The built in types used in translation. | 
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| 140 | const ast::StructDecl * except_decl; | 
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| 141 | const ast::StructDecl * node_decl; | 
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| 142 | const ast::StructDecl * hook_decl; | 
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| 143 |  | 
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| 144 | // The many helper functions for code/syntree generation. | 
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| 145 | ast::CompoundStmt * take_try_block( ast::TryStmt * tryStmt ); | 
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| 146 | ast::FunctionDecl * create_try_wrapper( const ast::CompoundStmt * body ); | 
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| 147 | ast::CaseClause * create_terminate_catch_case( | 
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| 148 | const ast::DeclWithType * except_obj, int index, ast::CatchClause * clause ); | 
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| 149 | ast::CompoundStmt * create_single_matcher( | 
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| 150 | const ast::DeclWithType * except_obj, ast::CatchClause * modded_handler ); | 
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| 151 | ast::FunctionDecl * create_terminate_match( CatchList &handlers ); | 
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| 152 | ast::CompoundStmt * create_terminate_caller( const CodeLocation & location, | 
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| 153 | ast::FunctionDecl * try_wrapper, ast::FunctionDecl * terminate_match, | 
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| 154 | CatchList & terminate_handlers ); | 
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| 155 | ast::FunctionDecl * create_resume_handler( CatchList &handlers ); | 
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| 156 | ast::CompoundStmt * create_resume_wrapper( | 
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| 157 | const ast::Stmt * wraps, const ast::FunctionDecl * resume_handler ); | 
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| 158 | ast::FunctionDecl * create_finally_wrapper( ast::TryStmt * tryStmt ); | 
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| 159 | ast::ObjectDecl * create_finally_hook( ast::FunctionDecl * finally_wrapper ); | 
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| 160 | ast::Stmt * create_resume_rethrow( const ast::ThrowStmt * throwStmt ); | 
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| 161 |  | 
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| 162 | // Types used in translation, first group are internal. | 
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| 163 | ast::ObjectDecl * make_index_object( CodeLocation const & ) const; | 
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| 164 | ast::ObjectDecl * make_exception_object( CodeLocation const & ) const; | 
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| 165 | ast::ObjectDecl * make_bool_object( CodeLocation const & ) const; | 
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| 166 | ast::ObjectDecl * make_voidptr_object( CodeLocation const & ) const; | 
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| 167 | ast::ObjectDecl * make_unused_index_object( CodeLocation const & ) const; | 
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| 168 |  | 
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| 169 | public: | 
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| 170 | TryMutatorCore() : | 
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| 171 | except_decl( nullptr ), node_decl( nullptr ), hook_decl( nullptr ) | 
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| 172 | {} | 
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| 173 |  | 
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| 174 | void previsit( const ast::StructDecl *structDecl ); | 
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| 175 | ast::Stmt * postvisit( const ast::TryStmt *tryStmt ); | 
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| 176 | ast::Stmt * postvisit( const ast::ThrowStmt *throwStmt ); | 
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| 177 | }; | 
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| 178 |  | 
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| 179 | ast::ObjectDecl * TryMutatorCore::make_index_object( | 
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| 180 | CodeLocation const & location ) const { | 
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| 181 | return new ast::ObjectDecl( | 
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| 182 | location, | 
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| 183 | "__handler_index", | 
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| 184 | new ast::BasicType( ast::BasicType::SignedInt ) | 
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| 185 | ); | 
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| 186 | } | 
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| 187 |  | 
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| 188 | ast::ObjectDecl * TryMutatorCore::make_exception_object( | 
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| 189 | CodeLocation const & location ) const { | 
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| 190 | assert( except_decl ); | 
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| 191 | return new ast::ObjectDecl( | 
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| 192 | location, | 
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| 193 | "__exception_inst", | 
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| 194 | new ast::PointerType( new ast::StructInstType( except_decl ) ) | 
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| 195 | ); | 
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| 196 | } | 
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| 197 |  | 
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| 198 | ast::ObjectDecl * TryMutatorCore::make_bool_object( | 
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| 199 | CodeLocation const & location ) const { | 
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| 200 | return new ast::ObjectDecl( | 
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| 201 | location, | 
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| 202 | "__ret_bool", | 
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| 203 | new ast::BasicType( ast::BasicType::Bool ), | 
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| 204 | nullptr, //init | 
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| 205 | ast::Storage::Classes{}, | 
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| 206 | ast::Linkage::Cforall, | 
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| 207 | nullptr, //width | 
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| 208 | std::vector<ast::ptr<ast::Attribute>>{ new ast::Attribute( "unused" ) } | 
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| 209 | ); | 
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| 210 | } | 
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| 211 |  | 
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| 212 | ast::ObjectDecl * TryMutatorCore::make_voidptr_object( | 
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| 213 | CodeLocation const & location ) const { | 
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| 214 | return new ast::ObjectDecl( | 
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| 215 | location, | 
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| 216 | "__hook", | 
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| 217 | new ast::PointerType( | 
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| 218 | new ast::VoidType() | 
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| 219 | ), | 
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| 220 | nullptr, //init | 
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| 221 | ast::Storage::Classes{}, | 
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| 222 | ast::Linkage::Cforall, | 
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| 223 | nullptr, //width | 
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| 224 | std::vector<ast::ptr<ast::Attribute>>{ new ast::Attribute( "unused" ) } | 
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| 225 | ); | 
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| 226 | } | 
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| 227 |  | 
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| 228 | ast::ObjectDecl * TryMutatorCore::make_unused_index_object( | 
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| 229 | CodeLocation const & location ) const { | 
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| 230 | return new ast::ObjectDecl( | 
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| 231 | location, | 
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| 232 | "__handler_index", | 
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| 233 | new ast::BasicType(ast::BasicType::SignedInt), | 
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| 234 | nullptr, | 
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| 235 | ast::Storage::Classes{}, | 
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| 236 | ast::Linkage::Cforall, | 
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| 237 | nullptr, //width | 
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| 238 | std::vector<ast::ptr<ast::Attribute>>{ new ast::Attribute( "unused" ) } | 
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| 239 | ); | 
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| 240 | } | 
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| 241 |  | 
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| 242 | // TryStmt Mutation Helpers | 
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| 243 |  | 
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| 244 | ast::FunctionDecl * TryMutatorCore::create_try_wrapper( | 
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| 245 | const ast::CompoundStmt *body ) { | 
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| 246 | // void (*try)(void) `body` | 
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| 247 | return new ast::FunctionDecl( | 
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| 248 | body->location, | 
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| 249 | "try", | 
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| 250 | {}, //no param | 
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| 251 | {}, //no return | 
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| 252 | ast::mutate( body ), | 
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| 253 | ast::Storage::Classes{}, | 
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| 254 | ast::Linkage::Cforall | 
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| 255 | ); | 
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| 256 | } | 
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| 257 |  | 
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| 258 | ast::CaseClause * TryMutatorCore::create_terminate_catch_case( | 
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| 259 | const ast::DeclWithType * except_obj, int index, ast::CatchClause * clause ) { | 
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| 260 | // case `index`: | 
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| 261 | // { | 
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| 262 | //     __attribute__((cleanup(__cfaehm_cleanup_terminate))) | 
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| 263 | //     `handler.decl` = { (virtual `decl.type`)`except` }; | 
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| 264 | //     `handler.body`; | 
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| 265 | // } | 
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| 266 | // break; | 
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| 267 | const CodeLocation & location = clause->location; | 
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| 268 |  | 
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| 269 | auto clause_except = clause->decl.strict_as<ast::ObjectDecl>(); | 
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| 270 | auto local_except = ast::deepCopy( clause_except ); | 
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| 271 | local_except->attributes.push_back( new ast::Attribute( | 
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| 272 | "cleanup", | 
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| 273 | { new ast::NameExpr( location, "__cfaehm_cleanup_terminate" ) } | 
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| 274 | ) ); | 
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| 275 |  | 
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| 276 | local_except->init = new ast::ListInit( location, { | 
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| 277 | new ast::SingleInit( location, | 
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| 278 | new ast::VirtualCastExpr( location, | 
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| 279 | new ast::VariableExpr( location, except_obj ), | 
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| 280 | ast::deepCopy( local_except->get_type() ) | 
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| 281 | ) | 
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| 282 | ) | 
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| 283 | } ); | 
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| 284 |  | 
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| 285 | ast::DeclReplacer::DeclMap mapping; | 
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| 286 | mapping[clause_except] = local_except; | 
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| 287 | const ast::Stmt * body = strict_dynamic_cast<const ast::Stmt *>( | 
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| 288 | ast::DeclReplacer::replace(clause->body, mapping)); | 
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| 289 |  | 
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| 290 | return new ast::CaseClause( location, | 
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| 291 | ast::ConstantExpr::from_int( location, index ), | 
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| 292 | { | 
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| 293 | new ast::CompoundStmt( location, { | 
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| 294 | new ast::DeclStmt( location, local_except ), | 
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| 295 | body, | 
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| 296 | } ), | 
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| 297 | new ast::BranchStmt( location, ast::BranchStmt::Break, | 
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| 298 | ast::Label( location ) ), | 
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| 299 | } | 
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| 300 | ); | 
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| 301 | } | 
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| 302 |  | 
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| 303 | // Create a single check from a moddified handler. | 
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| 304 | // except_obj is referenced, modded_handler will be freed. | 
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| 305 | ast::CompoundStmt * TryMutatorCore::create_single_matcher( | 
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| 306 | const ast::DeclWithType * except_obj, ast::CatchClause * modded_handler ) { | 
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| 307 | // { | 
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| 308 | //     `modded_handler.decl` | 
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| 309 | //     if ( `decl.name = (virtual `decl.type`)`except` | 
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| 310 | //             [&& `modded_handler.cond`] ) { | 
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| 311 | //         `modded_handler.body` | 
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| 312 | //     } | 
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| 313 | // } | 
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| 314 |  | 
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| 315 | const CodeLocation loc = modded_handler->location; | 
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| 316 | ast::CompoundStmt * block = new ast::CompoundStmt(loc); | 
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| 317 |  | 
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| 318 | // Local Declaration | 
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| 319 | const ast::ObjectDecl * local_except = | 
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| 320 | modded_handler->decl.strict_as<ast::ObjectDecl>(); | 
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| 321 | block->push_back( new ast::DeclStmt( loc,  local_except ) ); | 
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| 322 |  | 
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| 323 | // Check for type match. | 
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| 324 | ast::VirtualCastExpr * vcex = new ast::VirtualCastExpr(loc, | 
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| 325 | new ast::VariableExpr(loc, except_obj ), | 
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| 326 | local_except->get_type() | 
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| 327 | ); | 
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| 328 | ast::Expr * cond = ast::UntypedExpr::createAssign(loc, | 
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| 329 | new ast::VariableExpr(loc, local_except ), vcex ); | 
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| 330 |  | 
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| 331 | // Add the check on the conditional if it is provided. | 
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| 332 | if ( modded_handler->cond ) { | 
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| 333 | cond = new ast::LogicalExpr( loc, cond, modded_handler->cond, ast::LogicalFlag::AndExpr ); | 
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| 334 | } | 
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| 335 | // Construct the match condition. | 
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| 336 | block->push_back( new ast::IfStmt(loc, | 
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| 337 | cond, modded_handler->body, nullptr ) ); | 
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| 338 |  | 
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| 339 | return block; | 
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| 340 | } | 
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| 341 |  | 
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| 342 | ast::FunctionDecl * TryMutatorCore::create_terminate_match( | 
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| 343 | CatchList &handlers ) { | 
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| 344 | // int match(exception * except) { | 
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| 345 | //     HANDLER WRAPPERS { return `index`; } | 
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| 346 | // } | 
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| 347 |  | 
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| 348 | assert( !handlers.empty() ); | 
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| 349 | const CodeLocation & location = handlers.front()->location; | 
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| 350 |  | 
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| 351 | ast::CompoundStmt * body = new ast::CompoundStmt( location ); | 
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| 352 | const ast::DeclWithType * except_obj = make_exception_object( location ); | 
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| 353 |  | 
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| 354 | // Index 1..{number of handlers} | 
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| 355 | int index = 0; | 
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| 356 | for ( ast::CatchClause * handler : handlers ) { | 
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| 357 | ++index; | 
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| 358 |  | 
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| 359 | ast::ptr<ast::Stmt> other_body = new ast::ReturnStmt( handler->location, | 
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| 360 | ast::ConstantExpr::from_int( handler->location, index ) ); | 
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| 361 | handler->body.swap( other_body ); | 
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| 362 |  | 
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| 363 | body->push_back( create_single_matcher( except_obj, handler ) ); | 
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| 364 |  | 
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| 365 | handler->body.swap( other_body ); | 
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| 366 | } | 
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| 367 |  | 
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| 368 | body->push_back( new ast::ReturnStmt( location, | 
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| 369 | ast::ConstantExpr::from_int( location, 0 ) )); | 
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| 370 |  | 
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| 371 | // void (*match)(exception_t *) `body` | 
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| 372 | return new ast::FunctionDecl( | 
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| 373 | location, | 
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| 374 | "match", | 
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| 375 | { except_obj }, | 
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| 376 | { make_unused_index_object( location ) }, | 
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| 377 | body, | 
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| 378 | ast::Storage::Classes{}, | 
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| 379 | ast::Linkage::Cforall | 
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| 380 | ); | 
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| 381 | } | 
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| 382 |  | 
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| 383 | ast::CompoundStmt * TryMutatorCore::create_terminate_caller( | 
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| 384 | const CodeLocation & loc, | 
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| 385 | ast::FunctionDecl * try_wrapper, | 
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| 386 | ast::FunctionDecl * terminate_match, | 
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| 387 | CatchList & terminate_handlers ) { | 
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| 388 | // { | 
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| 389 | //     int __handler_index = __cfaehm_try_terminate(`try`, `match`); | 
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| 390 | //     if ( __handler_index ) { | 
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| 391 | //         `catch`( __handler_index, __cfaehm_get_current_termination() ); | 
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| 392 | //     } | 
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| 393 | // } | 
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| 394 |  | 
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| 395 | ast::ObjectDecl * index = make_index_object( loc ); | 
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| 396 | index->init = new ast::SingleInit( loc, | 
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| 397 | new ast::UntypedExpr( loc, | 
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| 398 | new ast::NameExpr( loc, "__cfaehm_try_terminate" ), | 
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| 399 | { | 
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| 400 | new ast::VariableExpr( loc, try_wrapper ), | 
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| 401 | new ast::VariableExpr( loc, terminate_match ), | 
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| 402 | } | 
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| 403 | ) | 
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| 404 | ); | 
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| 405 |  | 
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| 406 | ast::ObjectDecl * except = make_exception_object( loc ); | 
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| 407 | except->init = new ast::SingleInit( loc, | 
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| 408 | new ast::UntypedExpr( loc, | 
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| 409 | new ast::NameExpr( loc, "__cfaehm_get_current_termination" ) | 
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| 410 | ) | 
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| 411 | ); | 
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| 412 |  | 
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| 413 | std::vector<ast::ptr<ast::CaseClause>> cases; | 
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| 414 | for ( auto const & [index, handler] : enumerate( terminate_handlers ) ) { | 
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| 415 | cases.emplace_back( | 
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| 416 | create_terminate_catch_case( except, index + 1, handler ) ); | 
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| 417 | } | 
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| 418 | auto switch_stmt = new ast::SwitchStmt( loc, | 
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| 419 | new ast::VariableExpr( loc, index ), std::move( cases ) ); | 
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| 420 |  | 
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| 421 | return new ast::CompoundStmt( loc, { | 
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| 422 | new ast::DeclStmt( loc, index ), | 
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| 423 | new ast::IfStmt( loc, | 
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| 424 | new ast::VariableExpr( loc, index ), | 
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| 425 | new ast::CompoundStmt( loc, { | 
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| 426 | new ast::DeclStmt( loc, except ), | 
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| 427 | switch_stmt, | 
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| 428 | } ) | 
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| 429 | ), | 
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| 430 | } ); | 
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| 431 | } | 
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| 432 |  | 
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| 433 | ast::FunctionDecl * TryMutatorCore::create_resume_handler( | 
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| 434 | CatchList &handlers ) { | 
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| 435 | // bool handle(exception * except) { | 
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| 436 | //     HANDLER WRAPPERS { `hander->body`; return true; } | 
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| 437 | // } | 
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| 438 |  | 
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| 439 | assert( !handlers.empty() ); | 
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| 440 | const CodeLocation & location = handlers.front()->location; | 
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| 441 |  | 
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| 442 | ast::CompoundStmt * body = new ast::CompoundStmt( location ); | 
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| 443 | const ast::DeclWithType * except_obj = make_exception_object( location ); | 
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| 444 |  | 
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| 445 | CatchList::iterator it; | 
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| 446 | for ( it = handlers.begin() ; it != handlers.end() ; ++it ) { | 
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| 447 | ast::CatchClause * handler = *it; | 
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| 448 | const CodeLocation loc = handler->location; | 
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| 449 | // Modifiy body. | 
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| 450 | ast::CompoundStmt * handling_code; | 
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| 451 | if (handler->body.as<ast::CompoundStmt>()) { | 
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| 452 | handling_code = strict_dynamic_cast<ast::CompoundStmt*>( | 
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| 453 | handler->body.get_and_mutate() ); | 
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| 454 | } else { | 
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| 455 | handling_code = new ast::CompoundStmt(loc); | 
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| 456 | handling_code->push_back( handler->body ); | 
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| 457 | } | 
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| 458 | handling_code->push_back( new ast::ReturnStmt(loc, | 
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| 459 | ast::ConstantExpr::from_bool(loc, true ) ) ); | 
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| 460 | handler->body = handling_code; | 
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| 461 |  | 
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| 462 | // Create the handler. | 
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| 463 | body->push_back( create_single_matcher( except_obj, handler ) ); | 
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| 464 | *it = nullptr; | 
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| 465 | } | 
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| 466 |  | 
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| 467 | body->push_back( new ast::ReturnStmt( location, | 
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| 468 | ast::ConstantExpr::from_bool( location, false ) ) ); | 
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| 469 |  | 
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| 470 | // bool (*handle)(exception_t *) `body` | 
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| 471 | return new ast::FunctionDecl( | 
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| 472 | location, | 
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| 473 | "handle", | 
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| 474 | { except_obj }, | 
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| 475 | { make_bool_object( location ) }, | 
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| 476 | body, | 
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| 477 | ast::Storage::Classes{}, | 
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| 478 | ast::Linkage::Cforall | 
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| 479 | ); | 
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| 480 | } | 
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| 481 |  | 
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| 482 | ast::CompoundStmt * TryMutatorCore::create_resume_wrapper( | 
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| 483 | const ast::Stmt * wraps, | 
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| 484 | const ast::FunctionDecl * resume_handler ) { | 
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| 485 | const CodeLocation loc = wraps->location; | 
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| 486 | ast::CompoundStmt * body = new ast::CompoundStmt(loc); | 
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| 487 |  | 
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| 488 | // struct __try_resume_node __resume_node | 
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| 489 | //      __attribute__((cleanup( __cfaehm_try_resume_cleanup ))); | 
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| 490 | // ** unwinding of the stack here could cause problems ** | 
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| 491 | // ** however I don't think that can happen currently ** | 
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| 492 | // __cfaehm_try_resume_setup( &__resume_node, resume_handler ); | 
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| 493 |  | 
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| 494 | ast::ObjectDecl * obj = new ast::ObjectDecl( | 
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| 495 | loc, | 
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| 496 | "__resume_node", | 
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| 497 | new ast::StructInstType( | 
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| 498 | node_decl | 
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| 499 | ), | 
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| 500 | nullptr, | 
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| 501 | ast::Storage::Classes{}, | 
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| 502 | ast::Linkage::Cforall, | 
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| 503 | nullptr, | 
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| 504 | {new ast::Attribute("cleanup", {new ast::NameExpr(loc, "__cfaehm_try_resume_cleanup")})} | 
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| 505 | ); | 
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| 506 | appendDeclStmt( body, obj ); | 
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| 507 |  | 
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| 508 | ast::UntypedExpr *setup = new ast::UntypedExpr(loc, new ast::NameExpr(loc, | 
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| 509 | "__cfaehm_try_resume_setup" ) ); | 
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| 510 | setup->args.push_back( new ast::AddressExpr( loc, new ast::VariableExpr(loc, obj ) ) ); | 
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| 511 | setup->args.push_back( new ast::VariableExpr( loc, resume_handler ) ); | 
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| 512 |  | 
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| 513 | body->push_back( new ast::ExprStmt(loc, setup ) ); | 
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| 514 |  | 
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| 515 | body->push_back( wraps ); | 
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| 516 | return body; | 
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| 517 | } | 
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| 518 |  | 
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| 519 | ast::FunctionDecl * TryMutatorCore::create_finally_wrapper( | 
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| 520 | ast::TryStmt * tryStmt ) { | 
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| 521 | // void finally(__attribute__((unused)) void *) `finally->body` | 
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| 522 | const ast::FinallyClause * finally = tryStmt->finally; | 
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| 523 | return new ast::FunctionDecl( | 
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| 524 | tryStmt->location, | 
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| 525 | "finally", | 
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| 526 | { make_voidptr_object( tryStmt->location ) }, | 
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| 527 | {}, //return void | 
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| 528 | ast::mutate( finally->body.get() ), | 
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| 529 | ast::Storage::Classes{}, | 
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| 530 | ast::Linkage::Cforall, | 
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| 531 | {}, | 
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| 532 | { ast::Function::Inline } | 
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| 533 | ); | 
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| 534 | } | 
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| 535 |  | 
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| 536 | ast::ObjectDecl * TryMutatorCore::create_finally_hook( | 
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| 537 | ast::FunctionDecl * finally_wrapper ) { | 
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| 538 | // struct __cfaehm_cleanup_hook __finally_hook | 
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| 539 | //      __attribute__((cleanup( `finally_wrapper` ))); | 
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| 540 |  | 
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| 541 | const CodeLocation & location = finally_wrapper->location; | 
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| 542 | return new ast::ObjectDecl( | 
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| 543 | location, | 
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| 544 | "__finally_hook", | 
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| 545 | new ast::StructInstType( | 
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| 546 | hook_decl | 
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| 547 | ), | 
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| 548 | nullptr, | 
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| 549 | ast::Storage::Classes{}, | 
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| 550 | ast::Linkage::Cforall, | 
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| 551 | nullptr, | 
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| 552 | {new ast::Attribute("cleanup", {new ast::VariableExpr(location, finally_wrapper)})} | 
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| 553 | ); | 
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| 554 | } | 
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| 555 |  | 
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| 556 | ast::Stmt * TryMutatorCore::create_resume_rethrow( const ast::ThrowStmt *throwStmt ) { | 
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| 557 | // return false; | 
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| 558 | const CodeLocation loc = throwStmt->location; | 
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| 559 | ast::Stmt * result = new ast::ReturnStmt(loc, | 
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| 560 | ast::ConstantExpr::from_bool( loc, false ) | 
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| 561 | ); | 
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| 562 | result->labels = throwStmt->labels; | 
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| 563 | return result; | 
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| 564 | } | 
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| 565 |  | 
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| 566 | // Visiting/Mutating Functions | 
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| 567 | void TryMutatorCore::previsit( const ast::StructDecl *structDecl ) { | 
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| 568 | if ( !structDecl->body ) { | 
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| 569 | // Skip children? | 
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| 570 | return; | 
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| 571 | } else if ( structDecl->name == "__cfaehm_base_exception_t" ) { | 
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| 572 | assert( nullptr == except_decl ); | 
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| 573 | except_decl = structDecl; | 
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| 574 | } else if ( structDecl->name == "__cfaehm_try_resume_node" ) { | 
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| 575 | assert( nullptr == node_decl ); | 
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| 576 | node_decl = structDecl; | 
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| 577 | } else if ( structDecl->name == "__cfaehm_cleanup_hook" ) { | 
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| 578 | assert( nullptr == hook_decl ); | 
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| 579 | hook_decl = structDecl; | 
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| 580 | } | 
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| 581 | } | 
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| 582 |  | 
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| 583 | ast::Stmt * TryMutatorCore::postvisit( const ast::TryStmt *tryStmt ) { | 
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| 584 | assert( except_decl ); | 
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| 585 | assert( node_decl ); | 
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| 586 | assert( hook_decl ); | 
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| 587 |  | 
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| 588 | const CodeLocation loc = tryStmt->location; | 
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| 589 | ast::TryStmt * mutStmt = mutate(tryStmt); | 
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| 590 | // Generate a prefix for the function names? | 
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| 591 |  | 
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| 592 | ast::CompoundStmt * block = new ast::CompoundStmt( loc ); | 
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| 593 | // ast::CompoundStmt * inner = take_try_block( mutStmt ); | 
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| 594 | // this is never mutated so let node deletion do its job? | 
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| 595 | const ast::CompoundStmt * inner = mutStmt->body; | 
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| 596 |  | 
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| 597 | if ( mutStmt->finally ) { | 
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| 598 | // Define the helper function. | 
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| 599 | ast::FunctionDecl * finally_block = | 
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| 600 | create_finally_wrapper( mutStmt ); | 
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| 601 | appendDeclStmt( block, finally_block ); | 
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| 602 | // Create and add the finally cleanup hook. | 
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| 603 | appendDeclStmt( block, create_finally_hook( finally_block ) ); | 
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| 604 | } | 
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| 605 |  | 
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| 606 | CatchList termination_handlers; | 
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| 607 | CatchList resumption_handlers; | 
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| 608 |  | 
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| 609 | for (auto & handler: mutStmt->handlers) { | 
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| 610 | // xxx - should always be unique? mutate as safe const-cast | 
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| 611 | assert(handler->unique()); | 
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| 612 | if (handler->kind == ast::ExceptionKind::Resume) { | 
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| 613 | resumption_handlers.push_back(handler.get_and_mutate()); | 
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| 614 | } | 
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| 615 | else { | 
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| 616 | termination_handlers.push_back(handler.get_and_mutate()); | 
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| 617 | } | 
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| 618 | } | 
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| 619 |  | 
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| 620 | if ( resumption_handlers.size() ) { | 
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| 621 | // Define the helper function. | 
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| 622 | ast::FunctionDecl * resume_handler = | 
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| 623 | create_resume_handler( resumption_handlers ); | 
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| 624 | appendDeclStmt( block, resume_handler ); | 
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| 625 | // Prepare hooks | 
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| 626 | inner = create_resume_wrapper( inner, resume_handler ); | 
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| 627 | } | 
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| 628 |  | 
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| 629 | if ( termination_handlers.size() ) { | 
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| 630 | // Define the two helper functions. | 
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| 631 | ast::FunctionDecl * try_wrapper = create_try_wrapper( inner ); | 
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| 632 | appendDeclStmt( block, try_wrapper ); | 
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| 633 | ast::FunctionDecl * terminate_match = | 
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| 634 | create_terminate_match( termination_handlers ); | 
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| 635 | appendDeclStmt( block, terminate_match ); | 
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| 636 | // Build the call to the try wrapper. | 
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| 637 | inner = create_terminate_caller(inner->location, | 
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| 638 | try_wrapper, terminate_match, termination_handlers ); | 
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| 639 | } | 
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| 640 |  | 
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| 641 | // Embed the try block. | 
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| 642 | block->push_back( inner ); | 
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| 643 |  | 
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| 644 | return block; | 
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| 645 | } | 
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| 646 |  | 
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| 647 | ast::Stmt * TryMutatorCore::postvisit( const ast::ThrowStmt *throwStmt ) { | 
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| 648 | // Only valid `throwResume;` statements should remain. (2/3 checks) | 
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| 649 | assert( ast::ExceptionKind::Resume == throwStmt->kind && ! throwStmt->expr ); | 
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| 650 | return create_resume_rethrow( throwStmt ); | 
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| 651 | } | 
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| 652 |  | 
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| 653 | } // namespace | 
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| 654 |  | 
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| 655 | void translateThrows( ast::TranslationUnit & transUnit ) { | 
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| 656 | ast::Pass<TranslateThrowsCore>::run( transUnit ); | 
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| 657 | } | 
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| 658 |  | 
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| 659 | void translateTries( ast::TranslationUnit & transUnit ) { | 
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| 660 | ast::Pass<TryMutatorCore>::run(transUnit); | 
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| 661 | } | 
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| 662 |  | 
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| 663 | } // namespace ControlStruct | 
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| 664 |  | 
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| 665 | // Local Variables: // | 
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| 666 | // tab-width: 4 // | 
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| 667 | // mode: c++ // | 
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| 668 | // compile-command: "make install" // | 
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| 669 | // End: // | 
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