source: src/InitTweak/FixInit.cc@ 76e8c55

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors ctor deferred_resn demangler enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox memory new-ast new-ast-unique-expr new-env no_list persistent-indexer pthread-emulation qualifiedEnum resolv-new with_gc
Last change on this file since 76e8c55 was 4e06c1e, checked in by Peter A. Buhr <pabuhr@…>, 9 years ago

changes for switch and choose statements
  • Property mode set to 100644
File size: 27.0 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// FixInit.h --
8//
9// Author : Rob Schluntz
10// Created On : Wed Jan 13 16:29:30 2016
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Tue Jul 12 17:41:15 2016
13// Update Count : 34
14//
15
16#include <stack>
17#include <list>
18#include <iterator>
19#include <algorithm>
20#include "FixInit.h"
21#include "InitTweak.h"
22#include "ResolvExpr/Resolver.h"
23#include "ResolvExpr/typeops.h"
24#include "SynTree/Declaration.h"
25#include "SynTree/Type.h"
26#include "SynTree/Expression.h"
27#include "SynTree/Statement.h"
28#include "SynTree/Initializer.h"
29#include "SynTree/Mutator.h"
30#include "SymTab/Indexer.h"
31#include "GenPoly/PolyMutator.h"
32#include "SynTree/AddStmtVisitor.h"
33
34bool ctordtorp = false;
35bool ctorp = false;
36bool cpctorp = false;
37bool dtorp = false;
38#define PRINT( text ) if ( ctordtorp ) { text }
39#define CP_CTOR_PRINT( text ) if ( ctordtorp || cpctorp ) { text }
40#define DTOR_PRINT( text ) if ( ctordtorp || dtorp ) { text }
41
42namespace InitTweak {
43 namespace {
44 const std::list<Label> noLabels;
45 const std::list<Expression*> noDesignators;
46
47 class InsertImplicitCalls : public GenPoly::PolyMutator {
48 public:
49 /// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which
50 /// function calls need their parameters to be copy constructed
51 static void insert( std::list< Declaration * > & translationUnit );
52
53 virtual Expression * mutate( ApplicationExpr * appExpr );
54 };
55
56 class ResolveCopyCtors : public SymTab::Indexer {
57 public:
58 /// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr,
59 /// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
60 /// arguments and return value temporaries
61 static void resolveImplicitCalls( std::list< Declaration * > & translationUnit );
62
63 virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr );
64
65 /// create and resolve ctor/dtor expression: fname(var, [cpArg])
66 ApplicationExpr * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
67 /// true if type does not need to be copy constructed to ensure correctness
68 bool skipCopyConstruct( Type * );
69 private:
70 TypeSubstitution * env;
71 };
72
73 /// collects constructed object decls - used as a base class
74 class ObjDeclCollector : public AddStmtVisitor {
75 public:
76 typedef AddStmtVisitor Parent;
77 using Parent::visit;
78 typedef std::set< ObjectDecl * > ObjectSet;
79 virtual void visit( CompoundStmt *compoundStmt );
80 virtual void visit( DeclStmt *stmt );
81 protected:
82 ObjectSet curVars;
83 };
84
85 struct printSet {
86 typedef ObjDeclCollector::ObjectSet ObjectSet;
87 printSet( const ObjectSet & objs ) : objs( objs ) {}
88 const ObjectSet & objs;
89 };
90 std::ostream & operator<<( std::ostream & out, const printSet & set) {
91 out << "{ ";
92 for ( ObjectDecl * obj : set.objs ) {
93 out << obj->get_name() << ", " ;
94 } // for
95 out << " }";
96 return out;
97 }
98
99 class LabelFinder : public ObjDeclCollector {
100 public:
101 typedef ObjDeclCollector Parent;
102 typedef std::map< Label, ObjectSet > LabelMap;
103 // map of Label -> live variables at that label
104 LabelMap vars;
105
106 void handleStmt( Statement * stmt );
107
108 // xxx - This needs to be done better.
109 // allow some generalization among different kinds of nodes with with similar parentage (e.g. all
110 // expressions, all statements, etc.) important to have this to provide a single entry point so that as new
111 // subclasses are added, there is only one place that the code has to be updated, rather than ensure that
112 // every specialized class knows about every new kind of statement that might be added.
113 virtual void visit( CompoundStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
114 virtual void visit( ExprStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
115 virtual void visit( AsmStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
116 virtual void visit( IfStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
117 virtual void visit( WhileStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
118 virtual void visit( ForStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
119 virtual void visit( SwitchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
120 virtual void visit( CaseStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
121 virtual void visit( BranchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
122 virtual void visit( ReturnStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
123 virtual void visit( TryStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
124 virtual void visit( CatchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
125 virtual void visit( FinallyStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
126 virtual void visit( NullStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
127 virtual void visit( DeclStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
128 virtual void visit( ImplicitCtorDtorStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
129 };
130
131 class InsertDtors : public ObjDeclCollector {
132 public:
133 /// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
134 /// (currently by FixInit)
135 static void insert( std::list< Declaration * > & translationUnit );
136
137 typedef ObjDeclCollector Parent;
138 typedef std::list< ObjectDecl * > OrderedDecls;
139 typedef std::list< OrderedDecls > OrderedDeclsStack;
140
141 InsertDtors( LabelFinder & finder ) : labelVars( finder.vars ) {}
142
143 virtual void visit( ObjectDecl * objDecl );
144
145 virtual void visit( CompoundStmt * compoundStmt );
146 virtual void visit( ReturnStmt * returnStmt );
147 virtual void visit( BranchStmt * stmt );
148 private:
149 void handleGoto( BranchStmt * stmt );
150
151 LabelFinder::LabelMap & labelVars;
152 OrderedDeclsStack reverseDeclOrder;
153 };
154
155 class FixInit : public GenPoly::PolyMutator {
156 public:
157 /// expand each object declaration to use its constructor after it is declared.
158 static void fixInitializers( std::list< Declaration * > &translationUnit );
159
160 virtual DeclarationWithType * mutate( ObjectDecl *objDecl );
161 };
162
163 class FixCopyCtors : public GenPoly::PolyMutator {
164 public:
165 /// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors, call expression,
166 /// and destructors
167 static void fixCopyCtors( std::list< Declaration * > &translationUnit );
168
169 virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr );
170 };
171 } // namespace
172
173 void fix( std::list< Declaration * > & translationUnit ) {
174 InsertImplicitCalls::insert( translationUnit );
175 ResolveCopyCtors::resolveImplicitCalls( translationUnit );
176 InsertDtors::insert( translationUnit );
177 FixInit::fixInitializers( translationUnit );
178
179 // FixCopyCtors must happen after FixInit, so that destructors are placed correctly
180 FixCopyCtors::fixCopyCtors( translationUnit );
181 }
182
183 namespace {
184 void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
185 InsertImplicitCalls inserter;
186 mutateAll( translationUnit, inserter );
187 }
188
189 void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
190 ResolveCopyCtors resolver;
191 acceptAll( translationUnit, resolver );
192 }
193
194 void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
195 FixInit fixer;
196 mutateAll( translationUnit, fixer );
197 }
198
199 void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
200 LabelFinder finder;
201 InsertDtors inserter( finder );
202 acceptAll( translationUnit, finder );
203 acceptAll( translationUnit, inserter );
204 }
205
206 void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
207 FixCopyCtors fixer;
208 mutateAll( translationUnit, fixer );
209 }
210
211 Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
212 appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
213 assert( appExpr );
214
215 if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
216 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
217 // optimization: don't need to copy construct in order to call intrinsic functions
218 return appExpr;
219 } else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
220 FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
221 assert( ftype );
222 if ( (funcDecl->get_name() == "?{}" || funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
223 Type * t1 = ftype->get_parameters().front()->get_type();
224 Type * t2 = ftype->get_parameters().back()->get_type();
225 PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
226 assert( ptrType );
227
228 if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
229 // optimization: don't need to copy construct in order to call a copy constructor or
230 // assignment operator
231 return appExpr;
232 } // if
233 } else if ( funcDecl->get_name() == "^?{}" ) {
234 // correctness: never copy construct arguments to a destructor
235 return appExpr;
236 } // if
237 } // if
238 } // if
239 CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
240
241 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
242 ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
243 // save the type substitution onto the new node so that it is easy to find.
244 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
245 // The substitution is needed to obtain the type of temporary variables so that copy constructor
246 // calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
247 // copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
248 // saves the environment, or compute the types of temporaries here, but it's much simpler to
249 // save the environment here, and more cohesive to compute temporary variables and resolve copy
250 // constructor calls together.
251 assert( env );
252 expr->set_env( env );
253 return expr;
254 }
255
256 bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
257 return dynamic_cast< VarArgsType * >( type ) || GenPoly::getFunctionType( type );
258 }
259
260 ApplicationExpr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
261 assert( var );
262 UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
263 untyped->get_args().push_back( new AddressExpr( new VariableExpr( var ) ) );
264 if (cpArg) untyped->get_args().push_back( cpArg );
265
266 // resolve copy constructor
267 // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
268 // (VariableExpr and already resolved expression)
269 CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
270 ApplicationExpr * resolved = dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untyped, *this ) );
271 if ( resolved->get_env() ) {
272 env->add( *resolved->get_env() );
273 } // if
274
275 assert( resolved );
276 delete untyped;
277 return resolved;
278 }
279
280 void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
281 static UniqueName tempNamer("_tmp_cp");
282 static UniqueName retNamer("_tmp_cp_ret");
283
284 CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
285 Visitor::visit( impCpCtorExpr );
286 env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
287
288 ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
289
290 // take each argument and attempt to copy construct it.
291 for ( Expression * & arg : appExpr->get_args() ) {
292 CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
293 // xxx - need to handle tuple arguments
294 assert( ! arg->get_results().empty() );
295 Type * result = arg->get_results().front();
296 if ( skipCopyConstruct( result ) ) continue; // skip certain non-copyable types
297 // type may involve type variables, so apply type substitution to get temporary variable's actual type
298 result = result->clone();
299 impCpCtorExpr->get_env()->apply( result );
300 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
301 tmp->get_type()->set_isConst( false );
302
303 // create and resolve copy constructor
304 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
305 ApplicationExpr * cpCtor = makeCtorDtor( "?{}", tmp, arg );
306
307 // if the chosen constructor is intrinsic, the copy is unnecessary, so
308 // don't create the temporary and don't call the copy constructor
309 VariableExpr * function = dynamic_cast< VariableExpr * >( cpCtor->get_function() );
310 assert( function );
311 if ( function->get_var()->get_linkage() != LinkageSpec::Intrinsic ) {
312 // replace argument to function call with temporary
313 arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
314 impCpCtorExpr->get_tempDecls().push_back( tmp );
315 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
316 } // if
317 } // for
318
319 // each return value from the call needs to be connected with an ObjectDecl at the call site, which is
320 // initialized with the return value and is destructed later
321 // xxx - handle multiple return values
322 ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
323 // xxx - is this right? callExpr may not have the right environment, because it was attached at a higher
324 // level. Trying to pass that environment along.
325 callExpr->set_env( impCpCtorExpr->get_env()->clone() );
326 for ( Type * result : appExpr->get_results() ) {
327 result = result->clone();
328 impCpCtorExpr->get_env()->apply( result );
329 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
330 ret->get_type()->set_isConst( false );
331 impCpCtorExpr->get_returnDecls().push_back( ret );
332 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
333 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
334 } // for
335 CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
336 }
337
338
339 Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
340 CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
341
342 impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
343 assert( impCpCtorExpr );
344
345 std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
346 std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
347 std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
348
349 // add all temporary declarations and their constructors
350 for ( ObjectDecl * obj : tempDecls ) {
351 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
352 } // for
353 for ( ObjectDecl * obj : returnDecls ) {
354 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
355 } // for
356
357 // add destructors after current statement
358 for ( Expression * dtor : dtors ) {
359 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
360 } // for
361
362 // xxx - update to work with multiple return values
363 ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
364 Expression * callExpr = impCpCtorExpr->get_callExpr();
365
366 CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
367
368 // detach fields from wrapper node so that it can be deleted without deleting too much
369 dtors.clear();
370 tempDecls.clear();
371 returnDecls.clear();
372 impCpCtorExpr->set_callExpr( NULL );
373 impCpCtorExpr->set_env( NULL );
374 delete impCpCtorExpr;
375
376 if ( returnDecl ) {
377 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
378 assign->get_args().push_back( new VariableExpr( returnDecl ) );
379 assign->get_args().push_back( callExpr );
380 // know the result type of the assignment is the type of the LHS (minus the pointer), so
381 // add that onto the assignment expression so that later steps have the necessary information
382 assign->add_result( returnDecl->get_type()->clone() );
383
384 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
385 if ( callExpr->get_results().front()->get_isLvalue() ) {
386 // lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
387 // non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
388 // type of the return temporary from T to T* to properly capture the return value. Then dereference
389 // the result of the comma expression, since the lvalue returning call was originally wrapped with
390 // an AddressExpr. Effectively, this turns
391 // lvalue T f();
392 // &*f()
393 // into
394 // T * tmp_cp_retN;
395 // tmp_cp_ret_N = &*(tmp_cp_ret_N = &*f(), tmp_cp_ret);
396 // which work out in terms of types, but is pretty messy. It would be nice to find a better way.
397 assign->get_args().back() = new AddressExpr( assign->get_args().back() );
398
399 Type * resultType = returnDecl->get_type()->clone();
400 returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
401 UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
402 deref->get_args().push_back( retExpr );
403 deref->add_result( resultType );
404 retExpr = deref;
405 } // if
406 // xxx - might need to set env on retExpr...
407 // retExpr->set_env( env->clone() );
408 return retExpr;
409 } else {
410 return callExpr;
411 } // if
412 }
413
414 DeclarationWithType *FixInit::mutate( ObjectDecl *objDecl ) {
415 // first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
416 // is removed from the ObjectDecl
417 objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
418
419 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
420 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
421 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
422 if ( Statement * ctor = ctorInit->get_ctor() ) {
423 if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
424 // generate:
425 // static bool __objName_uninitialized = true;
426 // if (__objName_uninitialized) {
427 // __ctor(__objName);
428 // void dtor_atexit() {
429 // __dtor(__objName);
430 // }
431 // on_exit(dtorOnExit, &__objName);
432 // __objName_uninitialized = false;
433 // }
434
435 // generate first line
436 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
437 SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
438 ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
439 isUninitializedVar->fixUniqueId();
440
441 // void dtor_atexit(...) {...}
442 FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + "_dtor_atexit", DeclarationNode::NoStorageClass, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
443 dtorCaller->fixUniqueId();
444 dtorCaller->get_statements()->get_kids().push_back( ctorInit->get_dtor()->clone() );
445
446 // on_exit(dtor_atexit);
447 UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
448 callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
449
450 // __objName_uninitialized = false;
451 UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
452 setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
453 setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
454
455 // generate body of if
456 CompoundStmt * initStmts = new CompoundStmt( noLabels );
457 std::list< Statement * > & body = initStmts->get_kids();
458 body.push_back( ctor );
459 body.push_back( new DeclStmt( noLabels, dtorCaller ) );
460 body.push_back( new ExprStmt( noLabels, callAtexit ) );
461 body.push_back( new ExprStmt( noLabels, setTrue ) );
462
463 // put it all together
464 IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
465 stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
466 stmtsToAddAfter.push_back( ifStmt );
467 } else {
468 stmtsToAddAfter.push_back( ctor );
469 } // if
470 objDecl->set_init( NULL );
471 ctorInit->set_ctor( NULL );
472 } else if ( Initializer * init = ctorInit->get_init() ) {
473 objDecl->set_init( init );
474 ctorInit->set_init( NULL );
475 } else {
476 // no constructor and no initializer, which is okay
477 objDecl->set_init( NULL );
478 } // if
479 delete ctorInit;
480 } // if
481 return objDecl;
482 }
483
484 void ObjDeclCollector::visit( CompoundStmt *compoundStmt ) {
485 std::set< ObjectDecl * > prevVars = curVars;
486 Parent::visit( compoundStmt );
487 curVars = prevVars;
488 }
489
490 void ObjDeclCollector::visit( DeclStmt *stmt ) {
491 // keep track of all variables currently in scope
492 if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
493 curVars.insert( objDecl );
494 } // if
495 Parent::visit( stmt );
496 }
497
498 void LabelFinder::handleStmt( Statement * stmt ) {
499 // for each label, remember the variables in scope at that label.
500 for ( Label l : stmt->get_labels() ) {
501 vars[l] = curVars;
502 } // for
503 }
504
505 template<typename Iterator, typename OutputIterator>
506 void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
507 for ( Iterator it = begin ; it != end ; ++it ) {
508 // extract destructor statement from the object decl and insert it into the output. Note that this is
509 // only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
510 // calls an intrinsic dtor then the call must (and will) still be generated since the argument may
511 // contain side effects.
512 ObjectDecl * objDecl = *it;
513 ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
514 assert( ctorInit && ctorInit->get_dtor() );
515 *out++ = ctorInit->get_dtor()->clone();
516 } // for
517 }
518
519 void InsertDtors::visit( ObjectDecl * objDecl ) {
520 // remember non-static destructed objects so that their destructors can be inserted later
521 if ( objDecl->get_storageClass() != DeclarationNode::Static ) {
522 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
523 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
524 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
525 Statement * dtor = ctorInit->get_dtor();
526 if ( dtor && ! isInstrinsicSingleArgCallStmt( dtor ) ) {
527 // don't need to call intrinsic dtor, because it does nothing, but
528 // non-intrinsic dtors must be called
529 reverseDeclOrder.front().push_front( objDecl );
530 } // if
531 } // if
532 } // if
533 Parent::visit( objDecl );
534 }
535
536 void InsertDtors::visit( CompoundStmt * compoundStmt ) {
537 // visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
538 // when block is left, just the destructors associated with variables defined in this block, so push a new
539 // list to the top of the stack so that we can differentiate scopes
540 reverseDeclOrder.push_front( OrderedDecls() );
541 Parent::visit( compoundStmt );
542
543 // add destructors for the current scope that we're exiting
544 std::list< Statement * > & statements = compoundStmt->get_kids();
545 insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
546 reverseDeclOrder.pop_front();
547 }
548
549 void InsertDtors::visit( ReturnStmt * returnStmt ) {
550 // return exits all scopes, so dump destructors for all scopes
551 for ( OrderedDecls & od : reverseDeclOrder ) {
552 insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
553 } // for
554 }
555
556 // Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
557 // BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
558 // at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
559 // of the error. See C++ Reference 6.6 Jump Statements for details.
560 void InsertDtors::handleGoto( BranchStmt * stmt ) {
561 assert( stmt->get_target() != "" && "BranchStmt missing a label" );
562 // S_L = lvars = set of objects in scope at label definition
563 // S_G = curVars = set of objects in scope at goto statement
564 ObjectSet & lvars = labelVars[ stmt->get_target() ];
565
566 DTOR_PRINT(
567 std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
568 std::cerr << "S_G = " << printSet( curVars ) << std::endl;
569 std::cerr << "S_L = " << printSet( lvars ) << std::endl;
570 )
571
572 ObjectSet diff;
573 // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
574 std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
575 DTOR_PRINT(
576 std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
577 )
578 if ( ! diff.empty() ) {
579 throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
580 } // if
581 // S_G-S_L results in set of objects that must be destructed
582 diff.clear();
583 std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
584 DTOR_PRINT(
585 std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
586 )
587 if ( ! diff.empty() ) {
588 // go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
589 OrderedDecls ordered;
590 for ( OrderedDecls & rdo : reverseDeclOrder ) {
591 // add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
592 copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
593 } // for
594 insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
595 } // if
596 }
597
598 void InsertDtors::visit( BranchStmt * stmt ) {
599 switch( stmt->get_type() ) {
600 case BranchStmt::Continue:
601 case BranchStmt::Break:
602 // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
603 // always be empty), but it serves as a small sanity check.
604 case BranchStmt::Goto:
605 handleGoto( stmt );
606 break;
607 default:
608 assert( false );
609 } // switch
610 }
611 } // namespace
612} // namespace InitTweak
613
614// Local Variables: //
615// tab-width: 4 //
616// mode: c++ //
617// compile-command: "make install" //
618// End: //
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