source: src/InitTweak/FixInit.cc@ f48ed47

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 f48ed47 was 4b2589a, checked in by Rob Schluntz <rschlunt@…>, 9 years ago

clean up comments, remove dead code
  • Property mode set to 100644
File size: 27.1 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// FixInit.h --
8//
9// Author : Rob Schluntz
10// Created On : Wed Jan 13 16:29:30 2016
11// Last Modified By : Rob Schluntz
12// Last Modified On : Fri May 13 11:44:26 2016
13// Update Count : 30
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
50 /// so that it is easy to identify which function calls need their parameters
51 /// to be copy constructed
52 static void insert( std::list< Declaration * > & translationUnit );
53
54 virtual Expression * mutate( ApplicationExpr * appExpr );
55 };
56
57 class ResolveCopyCtors : public SymTab::Indexer {
58 public:
59 /// generate temporary ObjectDecls for each argument and return value of each
60 /// ImplicitCopyCtorExpr, generate/resolve copy construction expressions for each,
61 /// and generate/resolve destructors for both arguments and return value temporaries
62 static void resolveImplicitCalls( std::list< Declaration * > & translationUnit );
63
64 virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr );
65
66 /// create and resolve ctor/dtor expression: fname(var, [cpArg])
67 ApplicationExpr * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
68 /// true if type does not need to be copy constructed to ensure correctness
69 bool skipCopyConstruct( Type * );
70 private:
71 TypeSubstitution * env;
72 };
73
74 /// collects constructed object decls - used as a base class
75 class ObjDeclCollector : public AddStmtVisitor {
76 public:
77 typedef AddStmtVisitor Parent;
78 using Parent::visit;
79 typedef std::set< ObjectDecl * > ObjectSet;
80 virtual void visit( CompoundStmt *compoundStmt );
81 virtual void visit( DeclStmt *stmt );
82 protected:
83 ObjectSet curVars;
84 };
85
86 struct printSet {
87 typedef ObjDeclCollector::ObjectSet ObjectSet;
88 printSet( const ObjectSet & objs ) : objs( objs ) {}
89 const ObjectSet & objs;
90 };
91 std::ostream & operator<<( std::ostream & out, const printSet & set) {
92 out << "{ ";
93 for ( ObjectDecl * obj : set.objs ) {
94 out << obj->get_name() << ", " ;
95 }
96 out << " }";
97 return out;
98 }
99
100 class LabelFinder : public ObjDeclCollector {
101 public:
102 typedef ObjDeclCollector Parent;
103 typedef std::map< Label, ObjectSet > LabelMap;
104 // map of Label -> live variables at that label
105 LabelMap vars;
106
107 void handleStmt( Statement * stmt );
108
109 // xxx - This needs to be done better.
110 // allow some generalization among different kinds of nodes with
111 // with similar parentage (e.g. all expressions, all statements, etc.)
112 // important to have this to provide a single entry point so that as
113 // new subclasses are added, there is only one place that the code has
114 // to be updated, rather than ensure that every specialized class knows
115 // about every new kind of statement that might be added.
116 virtual void visit( CompoundStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
117 virtual void visit( ExprStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
118 virtual void visit( AsmStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
119 virtual void visit( IfStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
120 virtual void visit( WhileStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
121 virtual void visit( ForStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
122 virtual void visit( SwitchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
123 virtual void visit( ChooseStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
124 virtual void visit( FallthruStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
125 virtual void visit( CaseStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
126 virtual void visit( BranchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
127 virtual void visit( ReturnStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
128 virtual void visit( TryStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
129 virtual void visit( CatchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
130 virtual void visit( FinallyStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
131 virtual void visit( NullStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
132 virtual void visit( DeclStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
133 virtual void visit( ImplicitCtorDtorStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
134 };
135
136 class InsertDtors : public ObjDeclCollector {
137 public:
138 /// insert destructor calls at the appropriate places.
139 /// must happen before CtorInit nodes are removed (currently by FixInit)
140 static void insert( std::list< Declaration * > & translationUnit );
141
142 typedef ObjDeclCollector Parent;
143 typedef std::list< ObjectDecl * > OrderedDecls;
144 typedef std::list< OrderedDecls > OrderedDeclsStack;
145
146 InsertDtors( LabelFinder & finder ) : labelVars( finder.vars ) {}
147
148 virtual void visit( ObjectDecl * objDecl );
149
150 virtual void visit( CompoundStmt * compoundStmt );
151 virtual void visit( ReturnStmt * returnStmt );
152 virtual void visit( BranchStmt * stmt );
153 private:
154 void handleGoto( BranchStmt * stmt );
155
156 LabelFinder::LabelMap & labelVars;
157 OrderedDeclsStack reverseDeclOrder;
158 };
159
160 class FixInit : public GenPoly::PolyMutator {
161 public:
162 /// expand each object declaration to use its constructor after it is declared.
163 static void fixInitializers( std::list< Declaration * > &translationUnit );
164
165 virtual DeclarationWithType * mutate( ObjectDecl *objDecl );
166 };
167
168 class FixCopyCtors : public GenPoly::PolyMutator {
169 public:
170 /// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors,
171 /// call expression, and destructors
172 static void fixCopyCtors( std::list< Declaration * > &translationUnit );
173
174 virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr );
175 };
176 } // namespace
177
178 void fix( std::list< Declaration * > & translationUnit ) {
179 InsertImplicitCalls::insert( translationUnit );
180 ResolveCopyCtors::resolveImplicitCalls( translationUnit );
181 InsertDtors::insert( translationUnit );
182 FixInit::fixInitializers( translationUnit );
183
184 // FixCopyCtors must happen after FixInit, so that destructors are placed correctly
185 FixCopyCtors::fixCopyCtors( translationUnit );
186 }
187
188 namespace {
189 void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
190 InsertImplicitCalls inserter;
191 mutateAll( translationUnit, inserter );
192 }
193
194 void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
195 ResolveCopyCtors resolver;
196 acceptAll( translationUnit, resolver );
197 }
198
199 void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
200 FixInit fixer;
201 mutateAll( translationUnit, fixer );
202 }
203
204 void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
205 LabelFinder finder;
206 InsertDtors inserter( finder );
207 acceptAll( translationUnit, finder );
208 acceptAll( translationUnit, inserter );
209 }
210
211 void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
212 FixCopyCtors fixer;
213 mutateAll( translationUnit, fixer );
214 }
215
216 Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
217 appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
218 assert( appExpr );
219
220 if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
221 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
222 // optimization: don't need to copy construct in order to call intrinsic functions
223 return appExpr;
224 } else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
225 FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
226 assert( ftype );
227 if ( (funcDecl->get_name() == "?{}" || funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
228 Type * t1 = ftype->get_parameters().front()->get_type();
229 Type * t2 = ftype->get_parameters().back()->get_type();
230 PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
231 assert( ptrType );
232
233 if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
234 // optimization: don't need to copy construct in order to call a copy constructor or
235 // assignment operator
236 return appExpr;
237 }
238 } else if ( funcDecl->get_name() == "^?{}" ) {
239 // correctness: never copy construct arguments to a destructor
240 return appExpr;
241 }
242 }
243 }
244 CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
245
246 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
247 ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
248 // save the type substitution onto the new node so that it is easy to find.
249 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
250 // The substitution is needed to obtain the type of temporary variables so that copy constructor
251 // calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
252 // copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
253 // saves the environment, or compute the types of temporaries here, but it's much simpler to
254 // save the environment here, and more cohesive to compute temporary variables and resolve copy
255 // constructor calls together.
256 assert( env );
257 expr->set_env( env );
258 return expr;
259 }
260
261 bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
262 return dynamic_cast< VarArgsType * >( type ) || GenPoly::getFunctionType( type );
263 }
264
265 ApplicationExpr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
266 assert( var );
267 UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
268 untyped->get_args().push_back( new AddressExpr( new VariableExpr( var ) ) );
269 if (cpArg) untyped->get_args().push_back( cpArg );
270
271 // resolve copy constructor
272 // should only be one alternative for copy ctor and dtor expressions, since
273 // all arguments are fixed (VariableExpr and already resolved expression)
274 CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
275 ApplicationExpr * resolved = dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untyped, *this ) );
276 if ( resolved->get_env() ) {
277 env->add( *resolved->get_env() );
278 }
279
280 assert( resolved );
281 delete untyped;
282 return resolved;
283 }
284
285 void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
286 static UniqueName tempNamer("_tmp_cp");
287 static UniqueName retNamer("_tmp_cp_ret");
288
289 CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
290 Visitor::visit( impCpCtorExpr );
291 env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
292
293 ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
294
295 // take each argument and attempt to copy construct it.
296 for ( Expression * & arg : appExpr->get_args() ) {
297 CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
298 // xxx - need to handle tuple arguments
299 assert( ! arg->get_results().empty() );
300 Type * result = arg->get_results().front();
301 if ( skipCopyConstruct( result ) ) continue; // skip certain non-copyable types
302 // type may involve type variables, so apply type substitution to get temporary variable's actual type
303 result = result->clone();
304 impCpCtorExpr->get_env()->apply( result );
305 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
306 tmp->get_type()->set_isConst( false );
307
308 // create and resolve copy constructor
309 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
310 ApplicationExpr * cpCtor = makeCtorDtor( "?{}", tmp, arg );
311
312 // if the chosen constructor is intrinsic, the copy is unnecessary, so
313 // don't create the temporary and don't call the copy constructor
314 VariableExpr * function = dynamic_cast< VariableExpr * >( cpCtor->get_function() );
315 assert( function );
316 if ( function->get_var()->get_linkage() != LinkageSpec::Intrinsic ) {
317 // replace argument to function call with temporary
318 arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
319 impCpCtorExpr->get_tempDecls().push_back( tmp );
320 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
321 }
322 }
323
324 // each return value from the call needs to be connected with an ObjectDecl
325 // at the call site, which is initialized with the return value and is destructed
326 // later
327 // xxx - handle multiple return values
328 ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
329 // xxx - is this right? callExpr may not have the right environment, because it was attached
330 // at a higher level. Trying to pass that environment along.
331 callExpr->set_env( impCpCtorExpr->get_env()->clone() );
332 for ( Type * result : appExpr->get_results() ) {
333 result = result->clone();
334 impCpCtorExpr->get_env()->apply( result );
335 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
336 ret->get_type()->set_isConst( false );
337 impCpCtorExpr->get_returnDecls().push_back( ret );
338 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
339 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
340 }
341 CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
342 }
343
344
345 Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
346 CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
347
348 impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
349 assert( impCpCtorExpr );
350
351 std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
352 std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
353 std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
354
355 // add all temporary declarations and their constructors
356 for ( ObjectDecl * obj : tempDecls ) {
357 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
358 }
359 for ( ObjectDecl * obj : returnDecls ) {
360 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
361 }
362
363 // add destructors after current statement
364 for ( Expression * dtor : dtors ) {
365 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
366 }
367
368 // xxx - update to work with multiple return values
369 ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
370 Expression * callExpr = impCpCtorExpr->get_callExpr();
371
372 CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
373
374 // detach fields from wrapper node so that it can be deleted without deleting too much
375 dtors.clear();
376 tempDecls.clear();
377 returnDecls.clear();
378 impCpCtorExpr->set_callExpr( NULL );
379 impCpCtorExpr->set_env( NULL );
380 delete impCpCtorExpr;
381
382 if ( returnDecl ) {
383 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
384 assign->get_args().push_back( new VariableExpr( returnDecl ) );
385 assign->get_args().push_back( callExpr );
386 // know the result type of the assignment is the type of the LHS (minus the pointer), so
387 // add that onto the assignment expression so that later steps have the necessary information
388 assign->add_result( returnDecl->get_type()->clone() );
389
390 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
391 if ( callExpr->get_results().front()->get_isLvalue() ) {
392 // lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any
393 // lvalue returning non-intrinsic function. Add an AddressExpr to the call to negate
394 // the derefence and change the type of the return temporary from T to T* to properly
395 // capture the return value. Then dereference the result of the comma expression, since
396 // the lvalue returning call was originally wrapped with an AddressExpr.
397 // Effectively, this turns
398 // lvalue T f();
399 // &*f()
400 // into
401 // T * tmp_cp_retN;
402 // tmp_cp_ret_N = &*(tmp_cp_ret_N = &*f(), tmp_cp_ret);
403 // which work out in terms of types, but is pretty messy. It would be nice to find a better way.
404 assign->get_args().back() = new AddressExpr( assign->get_args().back() );
405
406 Type * resultType = returnDecl->get_type()->clone();
407 returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
408 UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
409 deref->get_args().push_back( retExpr );
410 deref->add_result( resultType );
411 retExpr = deref;
412 }
413 // xxx - might need to set env on retExpr...
414 // retExpr->set_env( env->clone() );
415 return retExpr;
416 } else {
417 return callExpr;
418 }
419 }
420
421 DeclarationWithType *FixInit::mutate( ObjectDecl *objDecl ) {
422 // first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors
423 // when the init is removed from the ObjectDecl
424 objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
425
426 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
427 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
428 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
429 if ( Statement * ctor = ctorInit->get_ctor() ) {
430 if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
431 // generate:
432 // static bool __objName_uninitialized = true;
433 // if (__objName_uninitialized) {
434 // __ctor(__objName);
435 // void dtor_atexit() {
436 // __dtor(__objName);
437 // }
438 // on_exit(dtorOnExit, &__objName);
439 // __objName_uninitialized = false;
440 // }
441
442 // generate first line
443 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
444 SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
445 ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
446 isUninitializedVar->fixUniqueId();
447
448 // void dtor_atexit(...) {...}
449 FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + "_dtor_atexit", DeclarationNode::NoStorageClass, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
450 dtorCaller->fixUniqueId();
451 dtorCaller->get_statements()->get_kids().push_back( ctorInit->get_dtor() );
452
453 // on_exit(dtor_atexit);
454 UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
455 callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
456
457 // __objName_uninitialized = false;
458 UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
459 setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
460 setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
461
462 // generate body of if
463 CompoundStmt * initStmts = new CompoundStmt( noLabels );
464 std::list< Statement * > & body = initStmts->get_kids();
465 body.push_back( ctor );
466 body.push_back( new DeclStmt( noLabels, dtorCaller ) );
467 body.push_back( new ExprStmt( noLabels, callAtexit ) );
468 body.push_back( new ExprStmt( noLabels, setTrue ) );
469
470 // put it all together
471 IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
472 stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
473 stmtsToAddAfter.push_back( ifStmt );
474 } else {
475 stmtsToAddAfter.push_back( ctor );
476 }
477 objDecl->set_init( NULL );
478 ctorInit->set_ctor( NULL );
479 } else if ( Initializer * init = ctorInit->get_init() ) {
480 objDecl->set_init( init );
481 ctorInit->set_init( NULL );
482 } else {
483 // no constructor and no initializer, which is okay
484 objDecl->set_init( NULL );
485 }
486 delete ctorInit;
487 }
488 return objDecl;
489 }
490
491 void ObjDeclCollector::visit( CompoundStmt *compoundStmt ) {
492 std::set< ObjectDecl * > prevVars = curVars;
493 Parent::visit( compoundStmt );
494 curVars = prevVars;
495 }
496
497 void ObjDeclCollector::visit( DeclStmt *stmt ) {
498 // keep track of all variables currently in scope
499 if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
500 curVars.insert( objDecl );
501 }
502 Parent::visit( stmt );
503 }
504
505 void LabelFinder::handleStmt( Statement * stmt ) {
506 // for each label, remember the variables in scope at that label.
507 for ( Label l : stmt->get_labels() ) {
508 vars[l] = curVars;
509 }
510 }
511
512 template<typename Iterator, typename OutputIterator>
513 void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
514 for ( Iterator it = begin ; it != end ; ++it ) {
515 // extract destructor statement from the object decl and
516 // insert it into the output. Note that this is only called
517 // on lists of non-static objects with implicit non-intrinsic
518 // dtors, so if the user manually calls an intrinsic dtor
519 // then the call must (and will) still be generated since
520 // the argument may contain side effects.
521 ObjectDecl * objDecl = *it;
522 ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
523 assert( ctorInit && ctorInit->get_dtor() );
524 *out++ = ctorInit->get_dtor()->clone();
525 }
526 }
527
528 void InsertDtors::visit( ObjectDecl * objDecl ) {
529 // remember non-static destructed objects so that their destructors can be inserted later
530 if ( objDecl->get_storageClass() != DeclarationNode::Static ) {
531 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
532 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
533 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
534 Statement * dtor = ctorInit->get_dtor();
535 if ( dtor && ! isInstrinsicSingleArgCallStmt( dtor ) ) {
536 // don't need to call intrinsic dtor, because it does nothing, but
537 // non-intrinsic dtors must be called
538 reverseDeclOrder.front().push_front( objDecl );
539 }
540 }
541 }
542 Parent::visit( objDecl );
543 }
544
545 void InsertDtors::visit( CompoundStmt * compoundStmt ) {
546 // visit statements - this will also populate reverseDeclOrder list.
547 // don't want to dump all destructors when block is left,
548 // just the destructors associated with variables defined in this block,
549 // so push a new list to the top of the stack so that we can differentiate scopes
550 reverseDeclOrder.push_front( OrderedDecls() );
551 Parent::visit( compoundStmt );
552
553 // add destructors for the current scope that we're exiting
554 std::list< Statement * > & statements = compoundStmt->get_kids();
555 insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
556 reverseDeclOrder.pop_front();
557 }
558
559 void InsertDtors::visit( ReturnStmt * returnStmt ) {
560 // return exits all scopes, so dump destructors for all scopes
561 for ( OrderedDecls & od : reverseDeclOrder ) {
562 insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
563 }
564 }
565
566 // Handle break/continue/goto in the same manner as C++.
567 // Basic idea: any objects that are in scope at the BranchStmt
568 // but not at the labelled (target) statement must be destructed.
569 // If there are any objects in scope at the target location but
570 // not at the BranchStmt then those objects would be uninitialized
571 // so notify the user of the error.
572 // See C++ Reference 6.6 Jump Statements for details.
573 void InsertDtors::handleGoto( BranchStmt * stmt ) {
574 assert( stmt->get_target() != "" && "BranchStmt missing a label" );
575 // S_L = lvars = set of objects in scope at label definition
576 // S_G = curVars = set of objects in scope at goto statement
577 ObjectSet & lvars = labelVars[ stmt->get_target() ];
578
579 DTOR_PRINT(
580 std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
581 std::cerr << "S_G = " << printSet( curVars ) << std::endl;
582 std::cerr << "S_L = " << printSet( lvars ) << std::endl;
583 )
584
585 ObjectSet diff;
586 // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
587 std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
588 DTOR_PRINT(
589 std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
590 )
591 if ( ! diff.empty() ) {
592 throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
593 }
594 // S_G-S_L results in set of objects that must be destructed
595 diff.clear();
596 std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
597 DTOR_PRINT(
598 std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
599 )
600 if ( ! diff.empty() ) {
601 // go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
602 OrderedDecls ordered;
603 for ( OrderedDecls & rdo : reverseDeclOrder ) {
604 // add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
605 copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
606 }
607 insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
608 }
609 }
610
611 void InsertDtors::visit( BranchStmt * stmt ) {
612 switch( stmt->get_type() ) {
613 case BranchStmt::Continue:
614 case BranchStmt::Break:
615 // could optimize the break/continue case, because the S_L-S_G check
616 // is unnecessary (this set should always be empty), but it serves
617 // as a small sanity check.
618 case BranchStmt::Goto:
619 handleGoto( stmt );
620 break;
621 default:
622 assert( false );
623 }
624 }
625 } // namespace
626} // namespace InitTweak
627
628// Local Variables: //
629// tab-width: 4 //
630// mode: c++ //
631// compile-command: "make install" //
632// End: //
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