source: src/ControlStruct/ExceptTranslateNew.cpp@ 88001dd

Last change on this file since 88001dd was 60e14fc, checked in by Andrew Beach <ajbeach@…>, 3 years ago

Fixed some whitespace.
  • Property mode set to 100644
File size: 22.1 KB
Line 
1//
2// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// ExceptTranslateNew.cpp -- Conversion of exception control flow structures.
8//
9// Author : Andrew Beach
10// Created On : Mon Nov 8 11:53:00 2021
11// Last Modified By : Andrew Beach
12// Last Modified On : Fri Mar 11 17:51:00 2022
13// Update Count : 2
14//
15
16#include "ExceptTranslate.h"
17
18#include "AST/Expr.hpp"
19#include "AST/Pass.hpp"
20#include "AST/Stmt.hpp"
21#include "AST/TranslationUnit.hpp"
22#include "AST/DeclReplacer.hpp"
23
24namespace ControlStruct {
25
26namespace {
27
28 typedef std::list<ast::CatchClause*> CatchList;
29
30 void appendDeclStmt( ast::CompoundStmt * block, ast::DeclWithType * item ) {
31 block->push_back(new ast::DeclStmt(block->location, item));
32 }
33
34class TranslateThrowsCore final : public ast::WithGuards {
35 const ast::ObjectDecl * terminateHandlerExcept;
36 enum Context { NoHandler, TerHandler, ResHandler } currentContext;
37
38 const ast::Stmt * createEitherThrow(
39 const ast::ThrowStmt * throwStmt, const char * funcName );
40 const ast::Stmt * createTerminateRethrow( const ast::ThrowStmt * );
41
42public:
43 TranslateThrowsCore() :
44 terminateHandlerExcept( nullptr ), currentContext( NoHandler )
45 {}
46
47 void previsit( const ast::CatchClause * stmt );
48 const ast::Stmt * postvisit( const ast::ThrowStmt * stmt );
49};
50
51const ast::Stmt * TranslateThrowsCore::createEitherThrow(
52 const ast::ThrowStmt * throwStmt, const char * funcName ) {
53 // `throwFunc`( `throwStmt->name` );
54 ast::UntypedExpr * call = new ast::UntypedExpr( throwStmt->location,
55 new ast::NameExpr( throwStmt->location, funcName )
56 );
57 call->args.push_back( throwStmt->expr );
58 return new ast::ExprStmt( throwStmt->location, call );
59}
60
61ast::VariableExpr * varOf( const ast::DeclWithType * decl ) {
62 return new ast::VariableExpr( decl->location, decl );
63}
64
65const ast::Stmt * TranslateThrowsCore::createTerminateRethrow(
66 const ast::ThrowStmt * stmt ) {
67 // { `terminate_handler_except` = 0p; __rethrow_terminate(); }
68 assert( nullptr == stmt->expr );
69 assert( terminateHandlerExcept );
70
71 ast::CompoundStmt * result = new ast::CompoundStmt(
72 stmt->location, {}, std::vector<ast::Label>( stmt->labels ) );
73 result->push_back( new ast::ExprStmt( stmt->location,
74 ast::UntypedExpr::createAssign(
75 stmt->location,
76 varOf( terminateHandlerExcept ),
77 ast::ConstantExpr::null(
78 stmt->location,
79 terminateHandlerExcept->type
80 )
81 )
82 ) );
83 result->push_back( new ast::ExprStmt( stmt->location, new ast::UntypedExpr(
84 stmt->location,
85 new ast::NameExpr( stmt->location, "__cfaehm_rethrow_terminate" )
86 ) ) );
87 return result;
88}
89
90void TranslateThrowsCore::previsit( const ast::CatchClause * stmt ) {
91 // Validate the statement's form.
92 const ast::ObjectDecl * decl = stmt->decl.as<ast::ObjectDecl>();
93 // Also checking the type would be nice.
94 if ( !decl || !decl->type.as<ast::PointerType>() ) {
95 std::string kind = (ast::Terminate == stmt->kind) ? "catch" : "catchResume";
96 SemanticError( stmt->location, kind + " must have pointer to an exception type" );
97 }
98
99 // Track the handler context.
100 if ( ast::Terminate == stmt->kind ) {
101 GuardValue( currentContext ) = TerHandler;
102 GuardValue( terminateHandlerExcept ) = decl;
103 } else {
104 GuardValue( currentContext ) = ResHandler;
105 }
106}
107
108const ast::Stmt * TranslateThrowsCore::postvisit(
109 const ast::ThrowStmt * stmt ) {
110 // Ignoring ThrowStmt::target for now.
111 // Handle Termination (Raise, Reraise, Error):
112 if ( ast::Terminate == stmt->kind ) {
113 if ( stmt->expr ) {
114 return createEitherThrow( stmt, "$throw" );
115 } else if ( TerHandler == currentContext ) {
116 return createTerminateRethrow( stmt );
117 } else {
118 abort( "Invalid throw in %s at %i\n",
119 stmt->location.filename.c_str(),
120 stmt->location.first_line);
121 }
122 // Handle Resumption (Raise, Reraise, Error):
123 } else {
124 if ( stmt->expr ) {
125 return createEitherThrow( stmt, "$throwResume" );
126 } else if ( ResHandler == currentContext ) {
127 // This has to be handled later.
128 return stmt;
129 } else {
130 abort( "Invalid throwResume in %s at %i\n",
131 stmt->location.filename.c_str(),
132 stmt->location.first_line);
133 }
134 }
135}
136
137
138class TryMutatorCore final {
139 // The built in types used in translation.
140 const ast::StructDecl * except_decl;
141 const ast::StructDecl * node_decl;
142 const ast::StructDecl * hook_decl;
143
144 // The many helper functions for code/syntree generation.
145 ast::CompoundStmt * take_try_block( ast::TryStmt * tryStmt );
146 ast::FunctionDecl * create_try_wrapper( const ast::CompoundStmt * body );
147 ast::FunctionDecl * create_terminate_catch( CatchList &handlers );
148 ast::CompoundStmt * create_single_matcher(
149 const ast::DeclWithType * except_obj, ast::CatchClause * modded_handler );
150 ast::FunctionDecl * create_terminate_match( CatchList &handlers );
151 ast::CompoundStmt * create_terminate_caller( CodeLocation loc, ast::FunctionDecl * try_wrapper,
152 ast::FunctionDecl * terminate_catch, ast::FunctionDecl * terminate_match );
153 ast::FunctionDecl * create_resume_handler( CatchList &handlers );
154 ast::CompoundStmt * create_resume_wrapper(
155 const ast::Stmt * wraps, const ast::FunctionDecl * resume_handler );
156 ast::FunctionDecl * create_finally_wrapper( ast::TryStmt * tryStmt );
157 ast::ObjectDecl * create_finally_hook( ast::FunctionDecl * finally_wrapper );
158 ast::Stmt * create_resume_rethrow( const ast::ThrowStmt * throwStmt );
159
160 // Types used in translation, first group are internal.
161 ast::ObjectDecl * make_index_object( CodeLocation const & ) const;
162 ast::ObjectDecl * make_exception_object( CodeLocation const & ) const;
163 ast::ObjectDecl * make_bool_object( CodeLocation const & ) const;
164 ast::ObjectDecl * make_voidptr_object( CodeLocation const & ) const;
165 ast::ObjectDecl * make_unused_index_object( CodeLocation const & ) const;
166 // void (*function)();
167 ast::FunctionDecl * make_try_function( CodeLocation const & ) const;
168 // void (*function)(int, exception);
169 ast::FunctionDecl * make_catch_function( CodeLocation const & ) const;
170 // int (*function)(exception);
171 ast::FunctionDecl * make_match_function( CodeLocation const & ) const;
172 // bool (*function)(exception);
173 ast::FunctionDecl * make_handle_function( CodeLocation const & ) const;
174 // void (*function)(__attribute__((unused)) void *);
175 ast::FunctionDecl * make_finally_function( CodeLocation const & ) const;
176
177public:
178 TryMutatorCore() :
179 except_decl( nullptr ), node_decl( nullptr ), hook_decl( nullptr )
180 {}
181
182 void previsit( const ast::StructDecl *structDecl );
183 ast::Stmt * postvisit( const ast::TryStmt *tryStmt );
184 ast::Stmt * postvisit( const ast::ThrowStmt *throwStmt );
185};
186
187ast::ObjectDecl * TryMutatorCore::make_index_object(
188 CodeLocation const & location ) const {
189 return new ast::ObjectDecl(
190 location,
191 "__handler_index",
192 new ast::BasicType( ast::BasicType::SignedInt )
193 );
194}
195
196ast::ObjectDecl * TryMutatorCore::make_exception_object(
197 CodeLocation const & location ) const {
198 assert( except_decl );
199 return new ast::ObjectDecl(
200 location,
201 "__exception_inst",
202 new ast::PointerType( new ast::StructInstType( except_decl ) )
203 );
204}
205
206ast::ObjectDecl * TryMutatorCore::make_bool_object(
207 CodeLocation const & location ) const {
208 return new ast::ObjectDecl(
209 location,
210 "__ret_bool",
211 new ast::BasicType( ast::BasicType::Bool ),
212 nullptr, //init
213 ast::Storage::Classes{},
214 ast::Linkage::Cforall,
215 nullptr, //width
216 std::vector<ast::ptr<ast::Attribute>>{ new ast::Attribute( "unused" ) }
217 );
218}
219
220ast::ObjectDecl * TryMutatorCore::make_voidptr_object(
221 CodeLocation const & location ) const {
222 return new ast::ObjectDecl(
223 location,
224 "__hook",
225 new ast::PointerType(
226 new ast::VoidType()
227 ),
228 nullptr, //init
229 ast::Storage::Classes{},
230 ast::Linkage::Cforall,
231 nullptr, //width
232 std::vector<ast::ptr<ast::Attribute>>{ new ast::Attribute( "unused" ) }
233 );
234}
235
236ast::ObjectDecl * TryMutatorCore::make_unused_index_object(
237 CodeLocation const & location ) const {
238 return new ast::ObjectDecl(
239 location,
240 "__handler_index",
241 new ast::BasicType(ast::BasicType::SignedInt),
242 nullptr,
243 ast::Storage::Classes{},
244 ast::Linkage::Cforall,
245 nullptr, //width
246 std::vector<ast::ptr<ast::Attribute>>{ new ast::Attribute( "unused" ) }
247 );
248}
249
250ast::FunctionDecl * TryMutatorCore::make_try_function(
251 CodeLocation const & location ) const {
252 return new ast::FunctionDecl(
253 location,
254 "try",
255 {}, //forall
256 {}, //no param
257 {}, //no return
258 nullptr,
259 ast::Storage::Classes{},
260 ast::Linkage::Cforall
261 );
262}
263
264ast::FunctionDecl * TryMutatorCore::make_catch_function(
265 CodeLocation const & location ) const {
266 return new ast::FunctionDecl(
267 location,
268 "catch",
269 {}, //forall
270 { make_index_object( location ), make_exception_object( location ) },
271 {}, //return void
272 nullptr,
273 ast::Storage::Classes{},
274 ast::Linkage::Cforall
275 );
276}
277
278ast::FunctionDecl * TryMutatorCore::make_match_function(
279 CodeLocation const & location ) const {
280 return new ast::FunctionDecl(
281 location,
282 "match",
283 {}, //forall
284 { make_exception_object( location ) },
285 { make_unused_index_object( location ) },
286 nullptr,
287 ast::Storage::Classes{},
288 ast::Linkage::Cforall
289 );
290}
291
292ast::FunctionDecl * TryMutatorCore::make_handle_function(
293 CodeLocation const & location ) const {
294 return new ast::FunctionDecl(
295 location,
296 "handle",
297 {}, //forall
298 { make_exception_object( location ) },
299 { make_bool_object( location ) },
300 nullptr,
301 ast::Storage::Classes{},
302 ast::Linkage::Cforall
303 );
304}
305
306ast::FunctionDecl * TryMutatorCore::make_finally_function(
307 CodeLocation const & location ) const {
308 return new ast::FunctionDecl(
309 location,
310 "finally",
311 {}, //forall
312 { make_voidptr_object( location ) },
313 {}, //return void
314 nullptr,
315 ast::Storage::Classes{},
316 ast::Linkage::Cforall,
317 {},
318 { ast::Function::Inline }
319 );
320}
321
322// TryStmt Mutation Helpers
323
324ast::FunctionDecl * TryMutatorCore::create_try_wrapper(
325 const ast::CompoundStmt *body ) {
326
327 ast::FunctionDecl * ret = make_try_function( body->location );
328 ret->stmts = body;
329 return ret;
330}
331
332ast::FunctionDecl * TryMutatorCore::create_terminate_catch(
333 CatchList &handlers ) {
334 std::vector<ast::ptr<ast::CaseClause>> handler_wrappers;
335
336 assert (!handlers.empty());
337 const CodeLocation loc = handlers.front()->location;
338
339 ast::FunctionDecl * func_t = make_catch_function( loc );
340 const ast::DeclWithType * index_obj = func_t->params.front();
341 const ast::DeclWithType * except_obj = func_t->params.back();
342
343 // Index 1..{number of handlers}
344 int index = 0;
345 CatchList::iterator it = handlers.begin();
346 for ( ; it != handlers.end() ; ++it ) {
347 ++index;
348 ast::CatchClause * handler = *it;
349 const CodeLocation loc = handler->location;
350
351 // case `index`:
352 // {
353 // `handler.decl` = { (virtual `decl.type`)`except` };
354 // `handler.body`;
355 // }
356 // return;
357 ast::CompoundStmt * block = new ast::CompoundStmt(loc);
358
359 // Just copy the exception value. (Post Validation)
360 const ast::ObjectDecl * handler_decl =
361 handler->decl.strict_as<ast::ObjectDecl>();
362 ast::ObjectDecl * local_except = ast::deepCopy(handler_decl);
363 ast::VirtualCastExpr * vcex = new ast::VirtualCastExpr(loc,
364 new ast::VariableExpr( loc, except_obj ),
365 local_except->get_type()
366 );
367 vcex->location = handler->location;
368 local_except->init = new ast::ListInit(loc, { new ast::SingleInit( loc, vcex ) });
369 block->push_back( new ast::DeclStmt( loc, local_except ) );
370
371 // Add the cleanup attribute.
372 local_except->attributes.push_back( new ast::Attribute(
373 "cleanup",
374 { new ast::NameExpr( loc, "__cfaehm_cleanup_terminate" ) }
375 ) );
376
377 ast::DeclReplacer::DeclMap mapping;
378 mapping[handler_decl] = local_except;
379 const ast::Stmt * mutBody = strict_dynamic_cast<const ast::Stmt *>(
380 ast::DeclReplacer::replace(handler->body, mapping));
381
382
383 block->push_back( mutBody );
384 // handler->body = nullptr;
385
386 handler_wrappers.push_back( new ast::CaseClause(loc,
387 ast::ConstantExpr::from_int(loc, index) ,
388 { block, new ast::ReturnStmt( loc, nullptr ) }
389 ));
390 }
391 // TODO: Some sort of meaningful error on default perhaps?
392
393 ast::SwitchStmt * handler_lookup = new ast::SwitchStmt( loc,
394 new ast::VariableExpr( loc, index_obj ),
395 std::move(handler_wrappers)
396 );
397 ast::CompoundStmt * body = new ast::CompoundStmt( loc, {handler_lookup} );
398
399 func_t->stmts = body;
400 return func_t;
401}
402
403// Create a single check from a moddified handler.
404// except_obj is referenced, modded_handler will be freed.
405ast::CompoundStmt * TryMutatorCore::create_single_matcher(
406 const ast::DeclWithType * except_obj, ast::CatchClause * modded_handler ) {
407 // {
408 // `modded_handler.decl`
409 // if ( `decl.name = (virtual `decl.type`)`except`
410 // [&& `modded_handler.cond`] ) {
411 // `modded_handler.body`
412 // }
413 // }
414
415 const CodeLocation loc = modded_handler->location;
416 ast::CompoundStmt * block = new ast::CompoundStmt(loc);
417
418 // Local Declaration
419 const ast::ObjectDecl * local_except =
420 modded_handler->decl.strict_as<ast::ObjectDecl>();
421 block->push_back( new ast::DeclStmt( loc, local_except ) );
422
423 // Check for type match.
424 ast::VirtualCastExpr * vcex = new ast::VirtualCastExpr(loc,
425 new ast::VariableExpr(loc, except_obj ),
426 local_except->get_type()
427 );
428 ast::Expr * cond = ast::UntypedExpr::createAssign(loc,
429 new ast::VariableExpr(loc, local_except ), vcex );
430
431 // Add the check on the conditional if it is provided.
432 if ( modded_handler->cond ) {
433 cond = new ast::LogicalExpr( loc, cond, modded_handler->cond, ast::LogicalFlag::AndExpr );
434 }
435 // Construct the match condition.
436 block->push_back( new ast::IfStmt(loc,
437 cond, modded_handler->body, nullptr ) );
438
439 return block;
440}
441
442ast::FunctionDecl * TryMutatorCore::create_terminate_match(
443 CatchList &handlers ) {
444 // int match(exception * except) {
445 // HANDLER WRAPPERS { return `index`; }
446 // }
447
448 assert (!handlers.empty());
449 const CodeLocation loc = handlers.front()->location;
450
451 ast::CompoundStmt * body = new ast::CompoundStmt(loc);
452
453 ast::FunctionDecl * func_t = make_match_function( loc );
454 const ast::DeclWithType * except_obj = func_t->params.back();
455
456 // Index 1..{number of handlers}
457 int index = 0;
458 CatchList::iterator it;
459 for ( it = handlers.begin() ; it != handlers.end() ; ++it ) {
460 ++index;
461 ast::CatchClause * handler = *it;
462
463 // Body should have been taken by create_terminate_catch.
464 // xxx - just ignore it?
465 // assert( nullptr == handler->get_body() );
466
467 // Create new body.
468 handler->body = new ast::ReturnStmt( handler->location,
469 ast::ConstantExpr::from_int( handler->location, index ) );
470
471 // Create the handler.
472 body->push_back( create_single_matcher( except_obj, handler ) );
473 *it = nullptr;
474 }
475
476 body->push_back( new ast::ReturnStmt(loc,
477 ast::ConstantExpr::from_int( loc, 0 ) ));
478
479 func_t->stmts = body;
480
481 return func_t;
482}
483
484ast::CompoundStmt * TryMutatorCore::create_terminate_caller(
485 CodeLocation loc,
486 ast::FunctionDecl * try_wrapper,
487 ast::FunctionDecl * terminate_catch,
488 ast::FunctionDecl * terminate_match ) {
489 // { __cfaehm_try_terminate(`try`, `catch`, `match`); }
490
491 ast::UntypedExpr * caller = new ast::UntypedExpr(loc, new ast::NameExpr(loc,
492 "__cfaehm_try_terminate" ) );
493 caller->args.push_back( new ast::VariableExpr(loc, try_wrapper ) );
494 caller->args.push_back( new ast::VariableExpr(loc, terminate_catch ) );
495 caller->args.push_back( new ast::VariableExpr(loc, terminate_match ) );
496
497 ast::CompoundStmt * callStmt = new ast::CompoundStmt(loc);
498 callStmt->push_back( new ast::ExprStmt( loc, caller ) );
499 return callStmt;
500}
501
502ast::FunctionDecl * TryMutatorCore::create_resume_handler(
503 CatchList &handlers ) {
504 // bool handle(exception * except) {
505 // HANDLER WRAPPERS { `hander->body`; return true; }
506 // }
507 assert (!handlers.empty());
508 const CodeLocation loc = handlers.front()->location;
509 ast::CompoundStmt * body = new ast::CompoundStmt(loc);
510
511 ast::FunctionDecl * func_t = make_handle_function( loc );
512 const ast::DeclWithType * except_obj = func_t->params.back();
513
514 CatchList::iterator it;
515 for ( it = handlers.begin() ; it != handlers.end() ; ++it ) {
516 ast::CatchClause * handler = *it;
517 const CodeLocation loc = handler->location;
518 // Modifiy body.
519 ast::CompoundStmt * handling_code;
520 if (handler->body.as<ast::CompoundStmt>()) {
521 handling_code = strict_dynamic_cast<ast::CompoundStmt*>(
522 handler->body.get_and_mutate() );
523 } else {
524 handling_code = new ast::CompoundStmt(loc);
525 handling_code->push_back( handler->body );
526 }
527 handling_code->push_back( new ast::ReturnStmt(loc,
528 ast::ConstantExpr::from_bool(loc, true ) ) );
529 handler->body = handling_code;
530
531 // Create the handler.
532 body->push_back( create_single_matcher( except_obj, handler ) );
533 *it = nullptr;
534 }
535
536 body->push_back( new ast::ReturnStmt(loc,
537 ast::ConstantExpr::from_bool(loc, false ) ) );
538 func_t->stmts = body;
539
540 return func_t;
541}
542
543ast::CompoundStmt * TryMutatorCore::create_resume_wrapper(
544 const ast::Stmt * wraps,
545 const ast::FunctionDecl * resume_handler ) {
546 const CodeLocation loc = wraps->location;
547 ast::CompoundStmt * body = new ast::CompoundStmt(loc);
548
549 // struct __try_resume_node __resume_node
550 // __attribute__((cleanup( __cfaehm_try_resume_cleanup )));
551 // ** unwinding of the stack here could cause problems **
552 // ** however I don't think that can happen currently **
553 // __cfaehm_try_resume_setup( &__resume_node, resume_handler );
554
555 ast::ObjectDecl * obj = new ast::ObjectDecl(
556 loc,
557 "__resume_node",
558 new ast::StructInstType(
559 node_decl
560 ),
561 nullptr,
562 ast::Storage::Classes{},
563 ast::Linkage::Cforall,
564 nullptr,
565 {new ast::Attribute("cleanup", {new ast::NameExpr(loc, "__cfaehm_try_resume_cleanup")})}
566 );
567 appendDeclStmt( body, obj );
568
569 ast::UntypedExpr *setup = new ast::UntypedExpr(loc, new ast::NameExpr(loc,
570 "__cfaehm_try_resume_setup" ) );
571 setup->args.push_back( new ast::AddressExpr( loc, new ast::VariableExpr(loc, obj ) ) );
572 setup->args.push_back( new ast::VariableExpr( loc, resume_handler ) );
573
574 body->push_back( new ast::ExprStmt(loc, setup ) );
575
576 body->push_back( wraps );
577 return body;
578}
579
580ast::FunctionDecl * TryMutatorCore::create_finally_wrapper(
581 ast::TryStmt * tryStmt ) {
582 // void finally() { `finally->block` }
583 const ast::FinallyClause * finally = tryStmt->finally;
584 const ast::CompoundStmt * body = finally->body;
585
586 ast::FunctionDecl * func_t = make_finally_function( tryStmt->location );
587 func_t->stmts = body;
588
589 tryStmt->finally = nullptr;
590
591 return func_t;
592}
593
594ast::ObjectDecl * TryMutatorCore::create_finally_hook(
595 ast::FunctionDecl * finally_wrapper ) {
596 // struct __cfaehm_cleanup_hook __finally_hook
597 // __attribute__((cleanup( `finally_wrapper` )));
598
599 const CodeLocation loc = finally_wrapper->location;
600 return new ast::ObjectDecl(
601 loc,
602 "__finally_hook",
603 new ast::StructInstType(
604 hook_decl
605 ),
606 nullptr,
607 ast::Storage::Classes{},
608 ast::Linkage::Cforall,
609 nullptr,
610 {new ast::Attribute("cleanup", {new ast::VariableExpr{loc, finally_wrapper}})}
611 );
612}
613
614ast::Stmt * TryMutatorCore::create_resume_rethrow( const ast::ThrowStmt *throwStmt ) {
615 // return false;
616 const CodeLocation loc = throwStmt->location;
617 ast::Stmt * result = new ast::ReturnStmt(loc,
618 ast::ConstantExpr::from_bool( loc, false )
619 );
620 result->labels = throwStmt->labels;
621 return result;
622}
623
624// Visiting/Mutating Functions
625void TryMutatorCore::previsit( const ast::StructDecl *structDecl ) {
626 if ( !structDecl->body ) {
627 // Skip children?
628 return;
629 } else if ( structDecl->name == "__cfaehm_base_exception_t" ) {
630 assert( nullptr == except_decl );
631 except_decl = structDecl;
632 } else if ( structDecl->name == "__cfaehm_try_resume_node" ) {
633 assert( nullptr == node_decl );
634 node_decl = structDecl;
635 } else if ( structDecl->name == "__cfaehm_cleanup_hook" ) {
636 assert( nullptr == hook_decl );
637 hook_decl = structDecl;
638 }
639}
640
641ast::Stmt * TryMutatorCore::postvisit( const ast::TryStmt *tryStmt ) {
642 assert( except_decl );
643 assert( node_decl );
644 assert( hook_decl );
645
646 const CodeLocation loc = tryStmt->location;
647 ast::TryStmt * mutStmt = mutate(tryStmt);
648 // Generate a prefix for the function names?
649
650 ast::CompoundStmt * block = new ast::CompoundStmt( loc );
651 // ast::CompoundStmt * inner = take_try_block( mutStmt );
652 // this is never mutated so let node deletion do its job?
653 const ast::CompoundStmt * inner = mutStmt->body;
654
655 if ( mutStmt->finally ) {
656 // Define the helper function.
657 ast::FunctionDecl * finally_block =
658 create_finally_wrapper( mutStmt );
659 appendDeclStmt( block, finally_block );
660 // Create and add the finally cleanup hook.
661 appendDeclStmt( block, create_finally_hook( finally_block ) );
662 }
663
664 CatchList termination_handlers;
665 CatchList resumption_handlers;
666
667 for (auto & handler: mutStmt->handlers) {
668 // xxx - should always be unique? mutate as safe const-cast
669 assert(handler->unique());
670 if (handler->kind == ast::ExceptionKind::Resume) {
671 resumption_handlers.push_back(handler.get_and_mutate());
672 }
673 else {
674 termination_handlers.push_back(handler.get_and_mutate());
675 }
676 }
677
678 if ( resumption_handlers.size() ) {
679 // Define the helper function.
680 ast::FunctionDecl * resume_handler =
681 create_resume_handler( resumption_handlers );
682 appendDeclStmt( block, resume_handler );
683 // Prepare hooks
684 inner = create_resume_wrapper( inner, resume_handler );
685 }
686
687 if ( termination_handlers.size() ) {
688 // Define the three helper functions.
689 ast::FunctionDecl * try_wrapper = create_try_wrapper( inner );
690 appendDeclStmt( block, try_wrapper );
691 ast::FunctionDecl * terminate_catch =
692 create_terminate_catch( termination_handlers );
693 appendDeclStmt( block, terminate_catch );
694 ast::FunctionDecl * terminate_match =
695 create_terminate_match( termination_handlers );
696 appendDeclStmt( block, terminate_match );
697 // Build the call to the try wrapper.
698 inner = create_terminate_caller(inner->location,
699 try_wrapper, terminate_catch, terminate_match );
700 }
701
702 // Embed the try block.
703 block->push_back( inner );
704
705 return block;
706}
707
708ast::Stmt * TryMutatorCore::postvisit( const ast::ThrowStmt *throwStmt ) {
709 // Only valid `throwResume;` statements should remain. (2/3 checks)
710 assert( ast::ExceptionKind::Resume == throwStmt->kind && ! throwStmt->expr );
711 return create_resume_rethrow( throwStmt );
712}
713
714} // namespace
715
716void translateThrows( ast::TranslationUnit & transUnit ) {
717 ast::Pass<TranslateThrowsCore>::run( transUnit );
718}
719
720void translateTries( ast::TranslationUnit & transUnit ) {
721 ast::Pass<TryMutatorCore>::run(transUnit);
722}
723
724} // namespace ControlStruct
725
726// Local Variables: //
727// tab-width: 4 //
728// mode: c++ //
729// compile-command: "make install" //
730// End: //
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