| 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.hpp"
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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::BasicKind::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::BasicKind::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::BasicKind::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;
 | 
|---|
| 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 );
 | 
|---|
| 579 |                 hook_decl = structDecl;
 | 
|---|
| 580 |         }
 | 
|---|
| 581 | }
 | 
|---|
| 582 | 
 | 
|---|
| 583 | ast::Stmt * TryMutatorCore::postvisit( const ast::TryStmt *tryStmt ) {
 | 
|---|
| 584 |         assert( except_decl );
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|---|
| 585 |         assert( node_decl );
 | 
|---|
| 586 |         assert( hook_decl );
 | 
|---|
| 587 | 
 | 
|---|
| 588 |         const CodeLocation loc = tryStmt->location;
 | 
|---|
| 589 |         ast::TryStmt * mutStmt = mutate(tryStmt);
 | 
|---|
| 590 |         // Generate a prefix for the function names?
 | 
|---|
| 591 | 
 | 
|---|
| 592 |         ast::CompoundStmt * block = new ast::CompoundStmt( loc );
 | 
|---|
| 593 |         // ast::CompoundStmt * inner = take_try_block( mutStmt );
 | 
|---|
| 594 |         // this is never mutated so let node deletion do its job?
 | 
|---|
| 595 |         const ast::CompoundStmt * inner = mutStmt->body;
 | 
|---|
| 596 | 
 | 
|---|
| 597 |         if ( mutStmt->finally ) {
 | 
|---|
| 598 |                 // Define the helper function.
 | 
|---|
| 599 |                 ast::FunctionDecl * finally_block =
 | 
|---|
| 600 |                         create_finally_wrapper( mutStmt );
 | 
|---|
| 601 |                 appendDeclStmt( block, finally_block );
 | 
|---|
| 602 |                 // Create and add the finally cleanup hook.
 | 
|---|
| 603 |                 appendDeclStmt( block, create_finally_hook( finally_block ) );
 | 
|---|
| 604 |         }
 | 
|---|
| 605 | 
 | 
|---|
| 606 |         CatchList termination_handlers;
 | 
|---|
| 607 |         CatchList resumption_handlers;
 | 
|---|
| 608 | 
 | 
|---|
| 609 |         for (auto & handler: mutStmt->handlers) {
 | 
|---|
| 610 |                 // xxx - should always be unique? mutate as safe const-cast
 | 
|---|
| 611 |                 assert(handler->unique());
 | 
|---|
| 612 |                 if (handler->kind == ast::ExceptionKind::Resume) {
 | 
|---|
| 613 |                         resumption_handlers.push_back(handler.get_and_mutate());
 | 
|---|
| 614 |                 }
 | 
|---|
| 615 |                 else {
 | 
|---|
| 616 |                         termination_handlers.push_back(handler.get_and_mutate());
 | 
|---|
| 617 |                 }
 | 
|---|
| 618 |         }
 | 
|---|
| 619 | 
 | 
|---|
| 620 |         if ( resumption_handlers.size() ) {
 | 
|---|
| 621 |                 // Define the helper function.
 | 
|---|
| 622 |                 ast::FunctionDecl * resume_handler =
 | 
|---|
| 623 |                         create_resume_handler( resumption_handlers );
 | 
|---|
| 624 |                 appendDeclStmt( block, resume_handler );
 | 
|---|
| 625 |                 // Prepare hooks
 | 
|---|
| 626 |                 inner = create_resume_wrapper( inner, resume_handler );
 | 
|---|
| 627 |         }
 | 
|---|
| 628 | 
 | 
|---|
| 629 |         if ( termination_handlers.size() ) {
 | 
|---|
| 630 |                 // Define the two helper functions.
 | 
|---|
| 631 |                 ast::FunctionDecl * try_wrapper = create_try_wrapper( inner );
 | 
|---|
| 632 |                 appendDeclStmt( block, try_wrapper );
 | 
|---|
| 633 |                 ast::FunctionDecl * terminate_match =
 | 
|---|
| 634 |                         create_terminate_match( termination_handlers );
 | 
|---|
| 635 |                 appendDeclStmt( block, terminate_match );
 | 
|---|
| 636 |                 // Build the call to the try wrapper.
 | 
|---|
| 637 |                 inner = create_terminate_caller(inner->location,
 | 
|---|
| 638 |                         try_wrapper, terminate_match, termination_handlers );
 | 
|---|
| 639 |         }
 | 
|---|
| 640 | 
 | 
|---|
| 641 |         // Embed the try block.
 | 
|---|
| 642 |         block->push_back( inner );
 | 
|---|
| 643 | 
 | 
|---|
| 644 |         return block;
 | 
|---|
| 645 | }
 | 
|---|
| 646 | 
 | 
|---|
| 647 | ast::Stmt * TryMutatorCore::postvisit( const ast::ThrowStmt *throwStmt ) {
 | 
|---|
| 648 |         // Only valid `throwResume;` statements should remain. (2/3 checks)
 | 
|---|
| 649 |         assert( ast::ExceptionKind::Resume == throwStmt->kind && ! throwStmt->expr );
 | 
|---|
| 650 |         return create_resume_rethrow( throwStmt );
 | 
|---|
| 651 | }
 | 
|---|
| 652 | 
 | 
|---|
| 653 | } // namespace
 | 
|---|
| 654 | 
 | 
|---|
| 655 | void translateThrows( ast::TranslationUnit & transUnit ) {
 | 
|---|
| 656 |         ast::Pass<TranslateThrowsCore>::run( transUnit );
 | 
|---|
| 657 | }
 | 
|---|
| 658 | 
 | 
|---|
| 659 | void translateTries( ast::TranslationUnit & transUnit ) {
 | 
|---|
| 660 |         ast::Pass<TryMutatorCore>::run(transUnit);
 | 
|---|
| 661 | }
 | 
|---|
| 662 | 
 | 
|---|
| 663 | } // namespace ControlStruct
 | 
|---|
| 664 | 
 | 
|---|
| 665 | // Local Variables: //
 | 
|---|
| 666 | // tab-width: 4 //
 | 
|---|
| 667 | // mode: c++ //
 | 
|---|
| 668 | // compile-command: "make install" //
 | 
|---|
| 669 | // End: //
 | 
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