source: src/InitTweak/FixInit.cc@ 29e8bf5

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 29e8bf5 was 72e9222, checked in by Rob Schluntz <rschlunt@…>, 9 years ago

change codegen for function-scoped static variable destruction to eliminate memory errors
  • Property mode set to 100644
File size: 29.6 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 "InitTweak.h"
21#include "FixInit.h"
22#include "FixGlobalInit.h"
23#include "ResolvExpr/Resolver.h"
24#include "ResolvExpr/typeops.h"
25#include "SynTree/Declaration.h"
26#include "SynTree/Type.h"
27#include "SynTree/Expression.h"
28#include "SynTree/Statement.h"
29#include "SynTree/Initializer.h"
30#include "SynTree/Mutator.h"
31#include "SymTab/Indexer.h"
32#include "GenPoly/PolyMutator.h"
33#include "SynTree/AddStmtVisitor.h"
34
35bool ctordtorp = false;
36bool ctorp = false;
37bool cpctorp = false;
38bool dtorp = false;
39#define PRINT( text ) if ( ctordtorp ) { text }
40#define CP_CTOR_PRINT( text ) if ( ctordtorp || cpctorp ) { text }
41#define DTOR_PRINT( text ) if ( ctordtorp || dtorp ) { text }
42
43namespace InitTweak {
44 namespace {
45 const std::list<Label> noLabels;
46 const std::list<Expression*> noDesignators;
47
48 class InsertImplicitCalls : public GenPoly::PolyMutator {
49 public:
50 /// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which
51 /// function calls need their parameters 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 ImplicitCopyCtorExpr,
60 /// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
61 /// 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 // debug
87 struct printSet {
88 typedef ObjDeclCollector::ObjectSet ObjectSet;
89 printSet( const ObjectSet & objs ) : objs( objs ) {}
90 const ObjectSet & objs;
91 };
92 std::ostream & operator<<( std::ostream & out, const printSet & set) {
93 out << "{ ";
94 for ( ObjectDecl * obj : set.objs ) {
95 out << obj->get_name() << ", " ;
96 } // for
97 out << " }";
98 return out;
99 }
100
101 class LabelFinder : public ObjDeclCollector {
102 public:
103 typedef ObjDeclCollector Parent;
104 typedef std::map< Label, ObjectSet > LabelMap;
105 // map of Label -> live variables at that label
106 LabelMap vars;
107
108 void handleStmt( Statement * stmt );
109
110 // xxx - This needs to be done better.
111 // allow some generalization among different kinds of nodes with with similar parentage (e.g. all
112 // expressions, all statements, etc.) important to have this to provide a single entry point so that as new
113 // subclasses are added, there is only one place that the code has to be updated, rather than ensure that
114 // every specialized class knows about every new kind of statement that might be added.
115 virtual void visit( CompoundStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
116 virtual void visit( ExprStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
117 virtual void visit( AsmStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
118 virtual void visit( IfStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
119 virtual void visit( WhileStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
120 virtual void visit( ForStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
121 virtual void visit( SwitchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
122 virtual void visit( CaseStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
123 virtual void visit( BranchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
124 virtual void visit( ReturnStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
125 virtual void visit( TryStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
126 virtual void visit( CatchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
127 virtual void visit( FinallyStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
128 virtual void visit( NullStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
129 virtual void visit( DeclStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
130 virtual void visit( ImplicitCtorDtorStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
131 };
132
133 class InsertDtors : public ObjDeclCollector {
134 public:
135 /// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
136 /// (currently by FixInit)
137 static void insert( std::list< Declaration * > & translationUnit );
138
139 typedef ObjDeclCollector Parent;
140 typedef std::list< ObjectDecl * > OrderedDecls;
141 typedef std::list< OrderedDecls > OrderedDeclsStack;
142
143 InsertDtors( LabelFinder & finder ) : labelVars( finder.vars ) {}
144
145 virtual void visit( ObjectDecl * objDecl );
146
147 virtual void visit( CompoundStmt * compoundStmt );
148 virtual void visit( ReturnStmt * returnStmt );
149 virtual void visit( BranchStmt * stmt );
150 private:
151 void handleGoto( BranchStmt * stmt );
152
153 LabelFinder::LabelMap & labelVars;
154 OrderedDeclsStack reverseDeclOrder;
155 };
156
157 class FixInit : public GenPoly::PolyMutator {
158 public:
159 /// expand each object declaration to use its constructor after it is declared.
160 static void fixInitializers( std::list< Declaration * > &translationUnit );
161
162 virtual DeclarationWithType * mutate( ObjectDecl *objDecl );
163
164 std::list< Declaration * > staticDtorDecls;
165 };
166
167 class FixCopyCtors : public GenPoly::PolyMutator {
168 public:
169 /// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors, call expression,
170 /// and destructors
171 static void fixCopyCtors( std::list< Declaration * > &translationUnit );
172
173 virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr );
174 };
175 } // namespace
176
177 void fix( std::list< Declaration * > & translationUnit, const std::string & filename, bool inLibrary ) {
178 // fixes ConstructorInit for global variables. should happen before fixInitializers.
179 InitTweak::fixGlobalInit( translationUnit, filename, inLibrary );
180
181 InsertImplicitCalls::insert( translationUnit );
182 ResolveCopyCtors::resolveImplicitCalls( translationUnit );
183 InsertDtors::insert( translationUnit );
184 FixInit::fixInitializers( translationUnit );
185
186 // FixCopyCtors must happen after FixInit, so that destructors are placed correctly
187 FixCopyCtors::fixCopyCtors( translationUnit );
188 }
189
190 namespace {
191 void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
192 InsertImplicitCalls inserter;
193 mutateAll( translationUnit, inserter );
194 }
195
196 void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
197 ResolveCopyCtors resolver;
198 acceptAll( translationUnit, resolver );
199 }
200
201 void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
202 FixInit fixer;
203
204 // can't use mutateAll, because need to insert declarations at top-level
205 // can't use DeclMutator, because sometimes need to insert IfStmt, etc.
206 SemanticError errors;
207 for ( std::list< Declaration * >::iterator i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
208 try {
209 *i = maybeMutate( *i, fixer );
210 // if (! fixer.staticDtorDecls.empty() ) {
211 translationUnit.splice( i, fixer.staticDtorDecls );
212 // }
213 } catch( SemanticError &e ) {
214 errors.append( e );
215 } // try
216 } // for
217 if ( ! errors.isEmpty() ) {
218 throw errors;
219 } // if
220 }
221
222 void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
223 LabelFinder finder;
224 InsertDtors inserter( finder );
225 acceptAll( translationUnit, finder );
226 acceptAll( translationUnit, inserter );
227 }
228
229 void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
230 FixCopyCtors fixer;
231 mutateAll( translationUnit, fixer );
232 }
233
234 Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
235 appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
236 assert( appExpr );
237
238 if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
239 if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
240 // optimization: don't need to copy construct in order to call intrinsic functions
241 return appExpr;
242 } else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
243 FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
244 assert( ftype );
245 if ( (funcDecl->get_name() == "?{}" || funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
246 Type * t1 = ftype->get_parameters().front()->get_type();
247 Type * t2 = ftype->get_parameters().back()->get_type();
248 PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
249 assert( ptrType );
250
251 if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
252 // optimization: don't need to copy construct in order to call a copy constructor or
253 // assignment operator
254 return appExpr;
255 } // if
256 } else if ( funcDecl->get_name() == "^?{}" ) {
257 // correctness: never copy construct arguments to a destructor
258 return appExpr;
259 } // if
260 } // if
261 } // if
262 CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
263
264 // wrap each function call so that it is easy to identify nodes that have to be copy constructed
265 ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
266 // save the type substitution onto the new node so that it is easy to find.
267 // Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
268 // The substitution is needed to obtain the type of temporary variables so that copy constructor
269 // calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
270 // copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
271 // saves the environment, or compute the types of temporaries here, but it's much simpler to
272 // save the environment here, and more cohesive to compute temporary variables and resolve copy
273 // constructor calls together.
274 assert( env );
275 expr->set_env( env );
276 return expr;
277 }
278
279 bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
280 return dynamic_cast< VarArgsType * >( type ) || GenPoly::getFunctionType( type );
281 }
282
283 ApplicationExpr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
284 assert( var );
285 UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
286 untyped->get_args().push_back( new AddressExpr( new VariableExpr( var ) ) );
287 if (cpArg) untyped->get_args().push_back( cpArg );
288
289 // resolve copy constructor
290 // should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
291 // (VariableExpr and already resolved expression)
292 CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
293 ApplicationExpr * resolved = dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untyped, *this ) );
294 if ( resolved->get_env() ) {
295 env->add( *resolved->get_env() );
296 } // if
297
298 assert( resolved );
299 delete untyped;
300 return resolved;
301 }
302
303 void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
304 static UniqueName tempNamer("_tmp_cp");
305 static UniqueName retNamer("_tmp_cp_ret");
306
307 CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
308 Visitor::visit( impCpCtorExpr );
309 env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
310
311 ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
312
313 // take each argument and attempt to copy construct it.
314 for ( Expression * & arg : appExpr->get_args() ) {
315 CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
316 // xxx - need to handle tuple arguments
317 assert( ! arg->get_results().empty() );
318 Type * result = arg->get_results().front();
319 if ( skipCopyConstruct( result ) ) continue; // skip certain non-copyable types
320 // type may involve type variables, so apply type substitution to get temporary variable's actual type
321 result = result->clone();
322 impCpCtorExpr->get_env()->apply( result );
323 ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
324 tmp->get_type()->set_isConst( false );
325
326 // create and resolve copy constructor
327 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
328 ApplicationExpr * cpCtor = makeCtorDtor( "?{}", tmp, arg );
329
330 // if the chosen constructor is intrinsic, the copy is unnecessary, so
331 // don't create the temporary and don't call the copy constructor
332 VariableExpr * function = dynamic_cast< VariableExpr * >( cpCtor->get_function() );
333 assert( function );
334 if ( function->get_var()->get_linkage() != LinkageSpec::Intrinsic ) {
335 // replace argument to function call with temporary
336 arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
337 impCpCtorExpr->get_tempDecls().push_back( tmp );
338 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
339 } // if
340 } // for
341
342 // each return value from the call needs to be connected with an ObjectDecl at the call site, which is
343 // initialized with the return value and is destructed later
344 // xxx - handle multiple return values
345 ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
346 // xxx - is this right? callExpr may not have the right environment, because it was attached at a higher
347 // level. Trying to pass that environment along.
348 callExpr->set_env( impCpCtorExpr->get_env()->clone() );
349 for ( Type * result : appExpr->get_results() ) {
350 result = result->clone();
351 impCpCtorExpr->get_env()->apply( result );
352 ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
353 ret->get_type()->set_isConst( false );
354 impCpCtorExpr->get_returnDecls().push_back( ret );
355 CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
356 impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
357 } // for
358 CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
359 }
360
361
362 Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
363 CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
364
365 impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
366 assert( impCpCtorExpr );
367
368 std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
369 std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
370 std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
371
372 // add all temporary declarations and their constructors
373 for ( ObjectDecl * obj : tempDecls ) {
374 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
375 } // for
376 for ( ObjectDecl * obj : returnDecls ) {
377 stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
378 } // for
379
380 // add destructors after current statement
381 for ( Expression * dtor : dtors ) {
382 stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
383 } // for
384
385 // xxx - update to work with multiple return values
386 ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
387 Expression * callExpr = impCpCtorExpr->get_callExpr();
388
389 CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
390
391 // detach fields from wrapper node so that it can be deleted without deleting too much
392 dtors.clear();
393 tempDecls.clear();
394 returnDecls.clear();
395 impCpCtorExpr->set_callExpr( NULL );
396 impCpCtorExpr->set_env( NULL );
397 delete impCpCtorExpr;
398
399 if ( returnDecl ) {
400 UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
401 assign->get_args().push_back( new VariableExpr( returnDecl ) );
402 assign->get_args().push_back( callExpr );
403 // know the result type of the assignment is the type of the LHS (minus the pointer), so
404 // add that onto the assignment expression so that later steps have the necessary information
405 assign->add_result( returnDecl->get_type()->clone() );
406
407 Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
408 if ( callExpr->get_results().front()->get_isLvalue() ) {
409 // lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
410 // non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
411 // type of the return temporary from T to T* to properly capture the return value. Then dereference
412 // the result of the comma expression, since the lvalue returning call was originally wrapped with
413 // an AddressExpr. Effectively, this turns
414 // lvalue T f();
415 // &*f()
416 // into
417 // T * tmp_cp_retN;
418 // tmp_cp_ret_N = &*(tmp_cp_ret_N = &*f(), tmp_cp_ret);
419 // which work out in terms of types, but is pretty messy. It would be nice to find a better way.
420 assign->get_args().back() = new AddressExpr( assign->get_args().back() );
421
422 Type * resultType = returnDecl->get_type()->clone();
423 returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
424 UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
425 deref->get_args().push_back( retExpr );
426 deref->add_result( resultType );
427 retExpr = deref;
428 } // if
429 // xxx - might need to set env on retExpr...
430 // retExpr->set_env( env->clone() );
431 return retExpr;
432 } else {
433 return callExpr;
434 } // if
435 }
436
437 DeclarationWithType *FixInit::mutate( ObjectDecl *objDecl ) {
438 // first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
439 // is removed from the ObjectDecl
440 objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
441
442 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
443 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
444 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
445 if ( Statement * ctor = ctorInit->get_ctor() ) {
446 if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
447 // originally wanted to take advantage of gcc nested functions, but
448 // we get memory errors with this approach. To remedy this, create a
449 // global static pointer that is set to refer to the object and make
450 // the dtor-caller function global so that.
451 //
452 // generate:
453 // T * __objName_static_ptrN;
454 // void __objName_dtor_atexitN() {
455 // __dtor(__objName_static_ptrN);
456 // }
457 // int f(...) {
458 // ...
459 // static T __objName;
460 // static bool __objName_uninitialized = true;
461 // if (__objName_uninitialized) {
462 // __objName_ptr = &__objName;
463 // __ctor(__objName);
464 // on_exit(__objName_dtor_atexitN, &__objName);
465 // __objName_uninitialized = false;
466 // }
467 // ...
468 // }
469
470 static UniqueName ptrNamer( "_static_ptr" );
471 static UniqueName dtorCallerNamer( "_dtor_atexit" );
472
473 // T * __objName_ptrN
474 ObjectDecl * objPtr = new ObjectDecl( objDecl->get_mangleName() + ptrNamer.newName(), DeclarationNode::Static, LinkageSpec::C, 0, new PointerType( Type::Qualifiers(), objDecl->get_type()->clone() ), 0 );
475 objPtr->fixUniqueId();
476
477 // void __objName_dtor_atexitN(...) {...}
478 // need to modify dtor call so that it refers to objPtr, since function will be global
479 Statement * dtorStmt = ctorInit->get_dtor()->clone();
480 ApplicationExpr * dtor = dynamic_cast< ApplicationExpr * >( InitTweak::getCtorDtorCall( dtorStmt ) );
481 assert( dtor );
482 delete dtor->get_args().front();
483 dtor->get_args().front() = new VariableExpr( objPtr );
484
485 FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + dtorCallerNamer.newName(), DeclarationNode::Static, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
486 dtorCaller->fixUniqueId();
487 dtorCaller->get_statements()->get_kids().push_back( dtorStmt );
488
489 // static bool __objName_uninitialized = true
490 BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
491 SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
492 ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
493 isUninitializedVar->fixUniqueId();
494
495 // __objName_static_ptrN = &__objName;
496 UntypedExpr * ptrAssign = new UntypedExpr( new NameExpr( "?=?" ) );
497 ptrAssign->get_args().push_back( new VariableExpr( objPtr ) );
498 ptrAssign->get_args().push_back( new AddressExpr( new VariableExpr( objDecl ) ) );
499
500 // atexit(dtor_atexit);
501 UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
502 callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
503
504 // __objName_uninitialized = false;
505 UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
506 setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
507 setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
508
509 // generate body of if
510 CompoundStmt * initStmts = new CompoundStmt( noLabels );
511 std::list< Statement * > & body = initStmts->get_kids();
512 body.push_back( ctor );
513 body.push_back( new ExprStmt( noLabels, ptrAssign ) );
514 body.push_back( new ExprStmt( noLabels, callAtexit ) );
515 body.push_back( new ExprStmt( noLabels, setTrue ) );
516
517 // put it all together
518 IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
519 stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
520 stmtsToAddAfter.push_back( ifStmt );
521
522 // add pointer and dtor caller decls to list of decls that will be added into global scope
523 staticDtorDecls.push_back( objPtr );
524 staticDtorDecls.push_back( dtorCaller );
525 } else {
526 stmtsToAddAfter.push_back( ctor );
527 } // if
528 objDecl->set_init( NULL );
529 ctorInit->set_ctor( NULL );
530 } else if ( Initializer * init = ctorInit->get_init() ) {
531 objDecl->set_init( init );
532 ctorInit->set_init( NULL );
533 } else {
534 // no constructor and no initializer, which is okay
535 objDecl->set_init( NULL );
536 } // if
537 delete ctorInit;
538 } // if
539 return objDecl;
540 }
541
542 void ObjDeclCollector::visit( CompoundStmt *compoundStmt ) {
543 std::set< ObjectDecl * > prevVars = curVars;
544 Parent::visit( compoundStmt );
545 curVars = prevVars;
546 }
547
548 void ObjDeclCollector::visit( DeclStmt *stmt ) {
549 // keep track of all variables currently in scope
550 if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
551 curVars.insert( objDecl );
552 } // if
553 Parent::visit( stmt );
554 }
555
556 void LabelFinder::handleStmt( Statement * stmt ) {
557 // for each label, remember the variables in scope at that label.
558 for ( Label l : stmt->get_labels() ) {
559 vars[l] = curVars;
560 } // for
561 }
562
563 template<typename Iterator, typename OutputIterator>
564 void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
565 for ( Iterator it = begin ; it != end ; ++it ) {
566 // extract destructor statement from the object decl and insert it into the output. Note that this is
567 // only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
568 // calls an intrinsic dtor then the call must (and will) still be generated since the argument may
569 // contain side effects.
570 ObjectDecl * objDecl = *it;
571 ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
572 assert( ctorInit && ctorInit->get_dtor() );
573 *out++ = ctorInit->get_dtor()->clone();
574 } // for
575 }
576
577 void InsertDtors::visit( ObjectDecl * objDecl ) {
578 // remember non-static destructed objects so that their destructors can be inserted later
579 if ( objDecl->get_storageClass() != DeclarationNode::Static ) {
580 if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
581 // a decision should have been made by the resolver, so ctor and init are not both non-NULL
582 assert( ! ctorInit->get_ctor() || ! ctorInit->get_init() );
583 Statement * dtor = ctorInit->get_dtor();
584 if ( dtor && ! isInstrinsicSingleArgCallStmt( dtor ) ) {
585 // don't need to call intrinsic dtor, because it does nothing, but
586 // non-intrinsic dtors must be called
587 reverseDeclOrder.front().push_front( objDecl );
588 } // if
589 } // if
590 } // if
591 Parent::visit( objDecl );
592 }
593
594 void InsertDtors::visit( CompoundStmt * compoundStmt ) {
595 // visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
596 // when block is left, just the destructors associated with variables defined in this block, so push a new
597 // list to the top of the stack so that we can differentiate scopes
598 reverseDeclOrder.push_front( OrderedDecls() );
599 Parent::visit( compoundStmt );
600
601 // add destructors for the current scope that we're exiting
602 std::list< Statement * > & statements = compoundStmt->get_kids();
603 insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
604 reverseDeclOrder.pop_front();
605 }
606
607 void InsertDtors::visit( ReturnStmt * returnStmt ) {
608 // return exits all scopes, so dump destructors for all scopes
609 for ( OrderedDecls & od : reverseDeclOrder ) {
610 insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
611 } // for
612 }
613
614 // Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
615 // BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
616 // at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
617 // of the error. See C++ Reference 6.6 Jump Statements for details.
618 void InsertDtors::handleGoto( BranchStmt * stmt ) {
619 assert( stmt->get_target() != "" && "BranchStmt missing a label" );
620 // S_L = lvars = set of objects in scope at label definition
621 // S_G = curVars = set of objects in scope at goto statement
622 ObjectSet & lvars = labelVars[ stmt->get_target() ];
623
624 DTOR_PRINT(
625 std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
626 std::cerr << "S_G = " << printSet( curVars ) << std::endl;
627 std::cerr << "S_L = " << printSet( lvars ) << std::endl;
628 )
629
630 ObjectSet diff;
631 // S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
632 std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
633 DTOR_PRINT(
634 std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
635 )
636 if ( ! diff.empty() ) {
637 throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
638 } // if
639 // S_G-S_L results in set of objects that must be destructed
640 diff.clear();
641 std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
642 DTOR_PRINT(
643 std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
644 )
645 if ( ! diff.empty() ) {
646 // go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
647 OrderedDecls ordered;
648 for ( OrderedDecls & rdo : reverseDeclOrder ) {
649 // add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
650 copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
651 } // for
652 insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
653 } // if
654 }
655
656 void InsertDtors::visit( BranchStmt * stmt ) {
657 switch( stmt->get_type() ) {
658 case BranchStmt::Continue:
659 case BranchStmt::Break:
660 // could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
661 // always be empty), but it serves as a small sanity check.
662 case BranchStmt::Goto:
663 handleGoto( stmt );
664 break;
665 default:
666 assert( false );
667 } // switch
668 }
669 } // namespace
670} // namespace InitTweak
671
672// Local Variables: //
673// tab-width: 4 //
674// mode: c++ //
675// compile-command: "make install" //
676// End: //
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