source: src/ControlStruct/MultiLevelExit.cpp@ 1b65595

ADT ast-experimental pthread-emulation
Last change on this file since 1b65595 was 0577df2, checked in by Andrew Beach <ajbeach@…>, 3 years ago

Various pieces of clean-up in MultiLevelExit.
  • Property mode set to 100644
File size: 21.8 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// MultiLevelExit.cpp -- Replaces CFA's local control flow with C's versions.
8//
9// Author : Andrew Beach
10// Created On : Mon Nov 1 13:48:00 2021
11// Last Modified By : Andrew Beach
12// Last Modified On : Mon Mar 28 9:42:00 2022
13// Update Count : 34
14//
15
16#include "MultiLevelExit.hpp"
17
18#include "AST/Pass.hpp"
19#include "AST/Stmt.hpp"
20#include "Common/CodeLocationTools.hpp"
21#include "LabelGeneratorNew.hpp"
22
23#include <set>
24using namespace std;
25using namespace ast;
26
27namespace ControlStruct {
28class Entry {
29 public:
30 const Stmt * stmt;
31 private:
32 // Organized like a manual ADT. Avoids creating a bunch of dead data.
33 struct Target {
34 Label label;
35 bool used = false;
36 Target( const Label & label ) : label( label ) {}
37 Target() : label( CodeLocation() ) {}
38 };
39 Target firstTarget;
40 Target secondTarget;
41
42 enum Kind {
43 ForStmtK, WhileDoStmtK, CompoundStmtK, IfStmtK, CaseClauseK, SwitchStmtK, TryStmtK
44 } kind;
45
46 bool fallDefaultValid = true;
47
48 static Label & useTarget( Target & target ) {
49 target.used = true;
50 return target.label;
51 }
52 public:
53 Entry( const ForStmt * stmt, Label breakExit, Label contExit ) :
54 stmt( stmt ), firstTarget( breakExit ), secondTarget( contExit ), kind( ForStmtK ) {}
55 Entry( const WhileDoStmt * stmt, Label breakExit, Label contExit ) :
56 stmt( stmt ), firstTarget( breakExit ), secondTarget( contExit ), kind( WhileDoStmtK ) {}
57 Entry( const CompoundStmt *stmt, Label breakExit ) :
58 stmt( stmt ), firstTarget( breakExit ), secondTarget(), kind( CompoundStmtK ) {}
59 Entry( const IfStmt *stmt, Label breakExit ) :
60 stmt( stmt ), firstTarget( breakExit ), secondTarget(), kind( IfStmtK ) {}
61 Entry( const CaseClause *, const CompoundStmt *stmt, Label fallExit ) :
62 stmt( stmt ), firstTarget( fallExit ), secondTarget(), kind( CaseClauseK ) {}
63 Entry( const SwitchStmt *stmt, Label breakExit, Label fallDefaultExit ) :
64 stmt( stmt ), firstTarget( breakExit ), secondTarget( fallDefaultExit ), kind( SwitchStmtK ) {}
65 Entry( const TryStmt *stmt, Label breakExit ) :
66 stmt( stmt ), firstTarget( breakExit ), secondTarget(), kind( TryStmtK ) {}
67
68 bool isContTarget() const { return kind <= WhileDoStmtK; }
69 bool isBreakTarget() const { return kind != CaseClauseK; }
70 bool isFallTarget() const { return kind == CaseClauseK; }
71 bool isFallDefaultTarget() const { return kind == SwitchStmtK; }
72
73 // These routines set a target as being "used" by a BranchStmt
74 Label useContExit() { assert( kind <= WhileDoStmtK ); return useTarget(secondTarget); }
75 Label useBreakExit() { assert( kind != CaseClauseK ); return useTarget(firstTarget); }
76 Label useFallExit() { assert( kind == CaseClauseK ); return useTarget(firstTarget); }
77 Label useFallDefaultExit() { assert( kind == SwitchStmtK ); return useTarget(secondTarget); }
78
79 // These routines check if a specific label for a statement is used by a BranchStmt
80 bool isContUsed() const { assert( kind <= WhileDoStmtK ); return secondTarget.used; }
81 bool isBreakUsed() const { assert( kind != CaseClauseK ); return firstTarget.used; }
82 bool isFallUsed() const { assert( kind == CaseClauseK ); return firstTarget.used; }
83 bool isFallDefaultUsed() const { assert( kind == SwitchStmtK ); return secondTarget.used; }
84 void seenDefault() { fallDefaultValid = false; }
85 bool isFallDefaultValid() const { return fallDefaultValid; }
86};
87
88// Helper predicates used in find_if calls (it doesn't take methods):
89bool isBreakTarget( const Entry & entry ) {
90 return entry.isBreakTarget();
91}
92
93bool isContinueTarget( const Entry & entry ) {
94 return entry.isContTarget();
95}
96
97bool isFallthroughTarget( const Entry & entry ) {
98 return entry.isFallTarget();
99}
100
101bool isFallthroughDefaultTarget( const Entry & entry ) {
102 return entry.isFallDefaultTarget();
103}
104
105struct MultiLevelExitCore final :
106 public WithVisitorRef<MultiLevelExitCore>,
107 public WithShortCircuiting, public WithGuards {
108 MultiLevelExitCore( const LabelToStmt & lt );
109
110 void previsit( const FunctionDecl * );
111
112 const CompoundStmt * previsit( const CompoundStmt * );
113 const BranchStmt * postvisit( const BranchStmt * );
114 void previsit( const WhileDoStmt * );
115 const WhileDoStmt * postvisit( const WhileDoStmt * );
116 void previsit( const ForStmt * );
117 const ForStmt * postvisit( const ForStmt * );
118 const CaseClause * previsit( const CaseClause * );
119 void previsit( const IfStmt * );
120 const IfStmt * postvisit( const IfStmt * );
121 void previsit( const SwitchStmt * );
122 const SwitchStmt * postvisit( const SwitchStmt * );
123 void previsit( const ReturnStmt * );
124 void previsit( const TryStmt * );
125 void postvisit( const TryStmt * );
126 void previsit( const FinallyClause * );
127
128 const Stmt * mutateLoop( const Stmt * body, Entry& );
129
130 const LabelToStmt & target_table;
131 set<Label> fallthrough_labels;
132 vector<Entry> enclosing_control_structures;
133 Label break_label;
134 bool inFinally;
135
136 template<typename LoopNode>
137 void prehandleLoopStmt( const LoopNode * loopStmt );
138 template<typename LoopNode>
139 const LoopNode * posthandleLoopStmt( const LoopNode * loopStmt );
140
141 list<ptr<Stmt>> fixBlock(
142 const list<ptr<Stmt>> & kids, bool caseClause );
143
144 template<typename UnaryPredicate>
145 auto findEnclosingControlStructure( UnaryPredicate pred ) {
146 return find_if( enclosing_control_structures.rbegin(),
147 enclosing_control_structures.rend(), pred );
148 }
149};
150
151NullStmt * labelledNullStmt( const CodeLocation & cl, const Label & label ) {
152 return new NullStmt( cl, vector<Label>{ label } );
153}
154
155MultiLevelExitCore::MultiLevelExitCore( const LabelToStmt & lt ) :
156 target_table( lt ), break_label( CodeLocation(), "" ),
157 inFinally( false )
158{}
159
160void MultiLevelExitCore::previsit( const FunctionDecl * ) {
161 visit_children = false;
162}
163
164const CompoundStmt * MultiLevelExitCore::previsit(
165 const CompoundStmt * stmt ) {
166 visit_children = false;
167
168 // if the stmt is labelled then generate a label to check in postvisit if the label is used
169 bool isLabeled = ! stmt->labels.empty();
170 if ( isLabeled ) {
171 Label breakLabel = newLabel( "blockBreak", stmt );
172 enclosing_control_structures.emplace_back( stmt, breakLabel );
173 GuardAction( [this]() { enclosing_control_structures.pop_back(); } );
174 }
175
176 auto mutStmt = mutate( stmt );
177 // A child statement may set the break label.
178 mutStmt->kids = fixBlock( stmt->kids, false );
179
180 if ( isLabeled ) {
181 assert( ! enclosing_control_structures.empty() );
182 Entry & entry = enclosing_control_structures.back();
183 if ( ! entry.useBreakExit().empty() ) {
184 break_label = entry.useBreakExit();
185 }
186 }
187 return mutStmt;
188}
189
190size_t getUnusedIndex( const Stmt * stmt, const Label & originalTarget ) {
191 const size_t size = stmt->labels.size();
192
193 // If the label is empty, do not add unused attribute.
194 if ( originalTarget.empty() ) return size;
195
196 // Search for a label that matches the originalTarget.
197 for ( size_t i = 0 ; i < size ; ++i ) {
198 const Label & label = stmt->labels[i];
199 if ( label == originalTarget ) {
200 for ( const Attribute * attr : label.attributes ) {
201 if ( attr->name == "unused" ) return size;
202 }
203 return i;
204 }
205 }
206 assertf( false, "CFA internal error: could not find label '%s' on statement %s",
207 originalTarget.name.c_str(), toString( stmt ).c_str() );
208}
209
210const Stmt * addUnused( const Stmt * stmt, const Label & originalTarget ) {
211 size_t i = getUnusedIndex( stmt, originalTarget );
212 if ( i == stmt->labels.size() ) {
213 return stmt;
214 }
215 Stmt * mutStmt = mutate( stmt );
216 mutStmt->labels[i].attributes.push_back( new Attribute( "unused" ) );
217 return mutStmt;
218}
219
220// This routine updates targets on enclosing control structures to indicate which
221// label is used by the BranchStmt that is passed
222const BranchStmt * MultiLevelExitCore::postvisit( const BranchStmt * stmt ) {
223 vector<Entry>::reverse_iterator targetEntry =
224 enclosing_control_structures.rend();
225
226 // Labels on different stmts require different approaches to access
227 switch ( stmt->kind ) {
228 case BranchStmt::Goto:
229 return stmt;
230 case BranchStmt::Continue:
231 case BranchStmt::Break: {
232 bool isContinue = stmt->kind == BranchStmt::Continue;
233 // Handle unlabeled break and continue.
234 if ( stmt->target.empty() ) {
235 if ( isContinue ) {
236 targetEntry = findEnclosingControlStructure( isContinueTarget );
237 } else {
238 if ( enclosing_control_structures.empty() ) {
239 SemanticError( stmt->location,
240 "'break' outside a loop, 'switch', or labelled block" );
241 }
242 targetEntry = findEnclosingControlStructure( isBreakTarget );
243 }
244 // Handle labeled break and continue.
245 } else {
246 // Lookup label in table to find attached control structure.
247 targetEntry = findEnclosingControlStructure(
248 [ targetStmt = target_table.at(stmt->target) ](auto entry){
249 return entry.stmt == targetStmt;
250 } );
251 }
252 // Ensure that selected target is valid.
253 if ( targetEntry == enclosing_control_structures.rend() || ( isContinue && ! isContinueTarget( *targetEntry ) ) ) {
254 SemanticError( stmt->location, toString( (isContinue ? "'continue'" : "'break'"),
255 " target must be an enclosing ", (isContinue ? "loop: " : "control structure: "),
256 stmt->originalTarget ) );
257 }
258 break;
259 }
260 // handle fallthrough in case/switch stmts
261 case BranchStmt::FallThrough: {
262 targetEntry = findEnclosingControlStructure( isFallthroughTarget );
263 // Check that target is valid.
264 if ( targetEntry == enclosing_control_structures.rend() ) {
265 SemanticError( stmt->location, "'fallthrough' must be enclosed in a 'switch' or 'choose'" );
266 }
267 if ( ! stmt->target.empty() ) {
268 // Labelled fallthrough: target must be a valid fallthough label.
269 if ( ! fallthrough_labels.count( stmt->target ) ) {
270 SemanticError( stmt->location, toString( "'fallthrough' target must be a later case statement: ",
271 stmt->originalTarget ) );
272 }
273 return new BranchStmt( stmt->location, BranchStmt::Goto, stmt->originalTarget );
274 }
275 break;
276 }
277 case BranchStmt::FallThroughDefault: {
278 targetEntry = findEnclosingControlStructure( isFallthroughDefaultTarget );
279
280 // Check if in switch or choose statement.
281 if ( targetEntry == enclosing_control_structures.rend() ) {
282 SemanticError( stmt->location, "'fallthrough' must be enclosed in a 'switch' or 'choose'" );
283 }
284
285 // Check if switch or choose has default clause.
286 auto switchStmt = strict_dynamic_cast< const SwitchStmt * >( targetEntry->stmt );
287 bool foundDefault = false;
288 for ( auto caseStmt : switchStmt->cases ) {
289 if ( caseStmt->isDefault() ) {
290 foundDefault = true;
291 break;
292 }
293 }
294 if ( ! foundDefault ) {
295 SemanticError( stmt->location, "'fallthrough default' must be enclosed in a 'switch' or 'choose'"
296 "control structure with a 'default' clause" );
297 }
298 break;
299 }
300 default:
301 assert( false );
302 }
303
304 // Branch error checks: get the appropriate label name, which is always replaced.
305 Label exitLabel( CodeLocation(), "" );
306 switch ( stmt->kind ) {
307 case BranchStmt::Break:
308 assert( ! targetEntry->useBreakExit().empty() );
309 exitLabel = targetEntry->useBreakExit();
310 break;
311 case BranchStmt::Continue:
312 assert( ! targetEntry->useContExit().empty() );
313 exitLabel = targetEntry->useContExit();
314 break;
315 case BranchStmt::FallThrough:
316 assert( ! targetEntry->useFallExit().empty() );
317 exitLabel = targetEntry->useFallExit();
318 break;
319 case BranchStmt::FallThroughDefault:
320 assert( ! targetEntry->useFallDefaultExit().empty() );
321 exitLabel = targetEntry->useFallDefaultExit();
322 // Check that fallthrough default comes before the default clause.
323 if ( ! targetEntry->isFallDefaultValid() ) {
324 SemanticError( stmt->location, "'fallthrough default' must precede the 'default' clause" );
325 }
326 break;
327 default:
328 assert(0);
329 }
330
331 // Add unused attribute to silence warnings.
332 targetEntry->stmt = addUnused( targetEntry->stmt, stmt->originalTarget );
333
334 // Replace with goto to make later passes more uniform.
335 return new BranchStmt( stmt->location, BranchStmt::Goto, exitLabel );
336}
337
338void MultiLevelExitCore::previsit( const WhileDoStmt * stmt ) {
339 return prehandleLoopStmt( stmt );
340}
341
342const WhileDoStmt * MultiLevelExitCore::postvisit( const WhileDoStmt * stmt ) {
343 return posthandleLoopStmt( stmt );
344}
345
346void MultiLevelExitCore::previsit( const ForStmt * stmt ) {
347 return prehandleLoopStmt( stmt );
348}
349
350const ForStmt * MultiLevelExitCore::postvisit( const ForStmt * stmt ) {
351 return posthandleLoopStmt( stmt );
352}
353
354// Mimic what the built-in push_front would do anyways. It is O(n).
355void push_front( vector<ptr<Stmt>> & vec, const Stmt * element ) {
356 vec.emplace_back( nullptr );
357 for ( size_t i = vec.size() - 1 ; 0 < i ; --i ) {
358 vec[ i ] = move( vec[ i - 1 ] );
359 }
360 vec[ 0 ] = element;
361}
362
363const CaseClause * MultiLevelExitCore::previsit( const CaseClause * stmt ) {
364 visit_children = false;
365
366 // If default, mark seen.
367 if ( stmt->isDefault() ) {
368 assert( ! enclosing_control_structures.empty() );
369 enclosing_control_structures.back().seenDefault();
370 }
371
372 // The cond may not exist, but if it does update it now.
373 visitor->maybe_accept( stmt, &CaseClause::cond );
374
375 // Just save the mutated node for simplicity.
376 CaseClause * mutStmt = mutate( stmt );
377
378 Label fallLabel = newLabel( "fallThrough", stmt->location );
379 if ( ! mutStmt->stmts.empty() ) {
380 // These should already be in a block.
381 auto first = mutStmt->stmts.front().get_and_mutate();
382 auto block = strict_dynamic_cast<CompoundStmt *>( first );
383
384 // Ensure that the stack isn't corrupted by exceptions in fixBlock.
385 auto guard = makeFuncGuard(
386 [&](){ enclosing_control_structures.emplace_back( mutStmt, block, fallLabel ); },
387 [this](){ enclosing_control_structures.pop_back(); }
388 );
389
390 block->kids = fixBlock( block->kids, true );
391
392 // Add fallthrough label if necessary.
393 assert( ! enclosing_control_structures.empty() );
394 Entry & entry = enclosing_control_structures.back();
395 if ( entry.isFallUsed() ) {
396 mutStmt->stmts.push_back( labelledNullStmt( block->location, entry.useFallExit() ) );
397 }
398 }
399 assert( ! enclosing_control_structures.empty() );
400 Entry & entry = enclosing_control_structures.back();
401 assertf( dynamic_cast< const SwitchStmt * >( entry.stmt ),
402 "CFA internal error: control structure enclosing a case clause must be a switch, but is: %s",
403 toString( entry.stmt ).c_str() );
404 if ( mutStmt->isDefault() ) {
405 if ( entry.isFallDefaultUsed() ) {
406 // Add fallthrough default label if necessary.
407 push_front( mutStmt->stmts, labelledNullStmt( stmt->location, entry.useFallDefaultExit() ) );
408 }
409 }
410 return mutStmt;
411}
412
413void MultiLevelExitCore::previsit( const IfStmt * stmt ) {
414 bool labeledBlock = ! stmt->labels.empty();
415 if ( labeledBlock ) {
416 Label breakLabel = newLabel( "blockBreak", stmt );
417 enclosing_control_structures.emplace_back( stmt, breakLabel );
418 GuardAction( [this](){ enclosing_control_structures.pop_back(); } );
419 }
420}
421
422const IfStmt * MultiLevelExitCore::postvisit( const IfStmt * stmt ) {
423 bool labeledBlock = ! stmt->labels.empty();
424 if ( labeledBlock ) {
425 auto this_label = enclosing_control_structures.back().useBreakExit();
426 if ( ! this_label.empty() ) {
427 break_label = this_label;
428 }
429 }
430 return stmt;
431}
432
433static bool isDefaultCase( const ptr<CaseClause> & caseClause ) {
434 return caseClause->isDefault();
435}
436
437void MultiLevelExitCore::previsit( const SwitchStmt * stmt ) {
438 Label label = newLabel( "switchBreak", stmt );
439 auto it = find_if( stmt->cases.rbegin(), stmt->cases.rend(), isDefaultCase );
440
441 const CaseClause * defaultCase = it != stmt->cases.rend() ? (*it) : nullptr;
442 Label defaultLabel = defaultCase ? newLabel( "fallThroughDefault", defaultCase->location ) : Label( stmt->location, "" );
443 enclosing_control_structures.emplace_back( stmt, label, defaultLabel );
444 GuardAction( [this]() { enclosing_control_structures.pop_back(); } );
445
446 // Collect valid labels for fallthrough. It starts with all labels at this level, then remove as each is seen during
447 // traversal.
448 for ( const CaseClause * caseStmt : stmt->cases ) {
449 if ( caseStmt->stmts.empty() ) continue;
450 auto block = caseStmt->stmts.front().strict_as<CompoundStmt>();
451 for ( const Stmt * stmt : block->kids ) {
452 for ( const Label & l : stmt->labels ) {
453 fallthrough_labels.insert( l );
454 }
455 }
456 }
457}
458
459const SwitchStmt * MultiLevelExitCore::postvisit( const SwitchStmt * stmt ) {
460 assert( ! enclosing_control_structures.empty() );
461 Entry & entry = enclosing_control_structures.back();
462 assert( entry.stmt == stmt );
463
464 // Only run to generate the break label.
465 if ( entry.isBreakUsed() ) {
466 // To keep the switch statements uniform (all direct children of a SwitchStmt should be CastStmts), append the
467 // exit label and break to the last case, create a default case if no cases.
468 SwitchStmt * mutStmt = mutate( stmt );
469 if ( mutStmt->cases.empty() ) {
470 mutStmt->cases.push_back( new CaseClause( mutStmt->location, nullptr, {} ) );
471 }
472
473 auto caseStmt = mutStmt->cases.back().get();
474 auto mutCase = mutate( caseStmt );
475 mutStmt->cases.back() = mutCase;
476
477 Label label( mutCase->location, "breakLabel" );
478 auto branch = new BranchStmt( mutCase->location, BranchStmt::Break, label );
479 branch->labels.push_back( entry.useBreakExit() );
480 mutCase->stmts.push_back( branch );
481
482 return mutStmt;
483 }
484 return stmt;
485}
486
487void MultiLevelExitCore::previsit( const ReturnStmt * stmt ) {
488 if ( inFinally ) {
489 SemanticError( stmt->location, "'return' may not appear in a finally clause" );
490 }
491}
492
493void MultiLevelExitCore::previsit( const TryStmt * stmt ) {
494 bool isLabeled = ! stmt->labels.empty();
495 if ( isLabeled ) {
496 Label breakLabel = newLabel( "blockBreak", stmt );
497 enclosing_control_structures.emplace_back( stmt, breakLabel );
498 GuardAction([this](){ enclosing_control_structures.pop_back(); } );
499 }
500}
501
502void MultiLevelExitCore::postvisit( const TryStmt * stmt ) {
503 bool isLabeled = ! stmt->labels.empty();
504 if ( isLabeled ) {
505 auto this_label = enclosing_control_structures.back().useBreakExit();
506 if ( ! this_label.empty() ) {
507 break_label = this_label;
508 }
509 }
510}
511
512void MultiLevelExitCore::previsit( const FinallyClause * ) {
513 GuardAction([this, old = move( enclosing_control_structures)](){ enclosing_control_structures = move(old); });
514 enclosing_control_structures = vector<Entry>();
515 GuardValue( inFinally ) = true;
516}
517
518const Stmt * MultiLevelExitCore::mutateLoop(
519 const Stmt * body, Entry & entry ) {
520 if ( entry.isBreakUsed() ) {
521 break_label = entry.useBreakExit();
522 }
523
524 // if continue is used insert a continue label into the back of the body of the loop
525 if ( entry.isContUsed() ) {
526 CompoundStmt * new_body = new CompoundStmt( body->location );
527 // {}
528 new_body->kids.push_back( body );
529 // {
530 // body
531 // }
532 new_body->kids.push_back(
533 labelledNullStmt( body->location, entry.useContExit() ) );
534 // {
535 // body
536 // ContinueLabel: {}
537 // }
538 return new_body;
539 }
540
541 return body;
542}
543
544template<typename LoopNode>
545void MultiLevelExitCore::prehandleLoopStmt( const LoopNode * loopStmt ) {
546 // Remember is loop before going onto mutate the body.
547 // The labels will be folded in if they are used.
548 Label breakLabel = newLabel( "loopBreak", loopStmt );
549 Label contLabel = newLabel( "loopContinue", loopStmt );
550 enclosing_control_structures.emplace_back( loopStmt, breakLabel, contLabel );
551 // labels are added temporarily to see if they are used and then added permanently in postvisit if ther are used
552 // children will tag labels as being used during their traversal which occurs before postvisit
553
554 // GuardAction calls the lambda after the node is done being visited
555 GuardAction( [this](){ enclosing_control_structures.pop_back(); } );
556}
557
558template<typename LoopNode>
559const LoopNode * MultiLevelExitCore::posthandleLoopStmt( const LoopNode * loopStmt ) {
560 assert( ! enclosing_control_structures.empty() );
561 Entry & entry = enclosing_control_structures.back();
562 assert( entry.stmt == loopStmt );
563
564 // Now check if the labels are used and add them if so.
565 return mutate_field( loopStmt, &LoopNode::body, mutateLoop( loopStmt->body, entry ) );
566 // this call to mutate_field compares loopStmt->body and the result of mutateLoop
567 // if they are the same the node isn't mutated, if they differ then the new mutated node is returned
568 // the stmts will only differ if a label is used
569}
570
571list<ptr<Stmt>> MultiLevelExitCore::fixBlock(
572 const list<ptr<Stmt>> & kids, bool is_case_clause ) {
573 // Unfortunately cannot use automatic error collection.
574 SemanticErrorException errors;
575
576 list<ptr<Stmt>> ret;
577
578 // Manually visit each child.
579 for ( const ptr<Stmt> & kid : kids ) {
580 if ( is_case_clause ) {
581 // Once a label is seen, it's no longer a valid for fallthrough.
582 for ( const Label & l : kid->labels ) {
583 fallthrough_labels.erase( l );
584 }
585 }
586
587 ptr<Stmt> else_stmt = nullptr;
588 const Stmt * loop_kid = nullptr;
589 // check if loop node and if so add else clause if it exists
590 const WhileDoStmt * whilePtr = kid.as<WhileDoStmt>();
591 if ( whilePtr && whilePtr->else_ ) {
592 else_stmt = whilePtr->else_;
593 loop_kid = mutate_field( whilePtr, &WhileDoStmt::else_, nullptr );
594 }
595 const ForStmt * forPtr = kid.as<ForStmt>();
596 if ( forPtr && forPtr->else_ ) {
597 else_stmt = forPtr->else_;
598 loop_kid = mutate_field( forPtr, &ForStmt::else_, nullptr );
599 }
600
601 try {
602 if (else_stmt) ret.push_back( loop_kid->accept( *visitor ) );
603 else ret.push_back( kid->accept( *visitor ) );
604 } catch ( SemanticErrorException & e ) {
605 errors.append( e );
606 }
607
608 if (else_stmt) ret.push_back(else_stmt);
609
610 if ( ! break_label.empty() ) {
611 ret.push_back( labelledNullStmt( ret.back()->location, break_label ) );
612 break_label = Label( CodeLocation(), "" );
613 }
614 }
615
616 if ( ! errors.isEmpty() ) {
617 throw errors;
618 }
619 return ret;
620}
621
622const CompoundStmt * multiLevelExitUpdate(
623 const CompoundStmt * stmt,
624 const LabelToStmt & labelTable ) {
625 // Must start in the body, so FunctionDecls can be a stopping point.
626 Pass<MultiLevelExitCore> visitor( labelTable );
627 const CompoundStmt * ret = stmt->accept( visitor );
628 // There are some unset code locations slipping in, possibly by Labels.
629 const Node * node = localFillCodeLocations( ret->location, ret );
630 return strict_dynamic_cast<const CompoundStmt *>( node );
631}
632} // namespace ControlStruct
633
634// Local Variables: //
635// tab-width: 4 //
636// mode: c++ //
637// compile-command: "make install" //
638// End: //
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