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source: src/InitTweak/FixInit.cc @ 72e9222

ADTaaron-thesisarm-ehast-experimentalcleanup-dtorsctordeferred_resndemanglerenumforall-pointer-decayjacob/cs343-translationjenkins-sandboxmemorynew-astnew-ast-unique-exprnew-envno_listpersistent-indexerpthread-emulationqualifiedEnumresolv-newwith_gc

Last change on this file since 72e9222 was 72e9222, checked in by Rob Schluntz <rschlunt@…>, 8 years ago
change codegen for function-scoped static variable destruction to eliminate memory errors
Property mode set to `100644`
File size: 29.6 KB

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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
35	bool ctordtorp = false;
36	bool ctorp = false;
37	bool cpctorp = false;
38	bool 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
43	namespace 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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