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source: src/InitTweak/FixInit.cc @ 486341f

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Last change on this file since 486341f was 486341f, checked in by Rob Schluntz <rschlunt@…>, 8 years ago
add option to CodeGen? to output unmangled name, add ctorWarnings test
Property mode set to `100644`
File size: 34.9 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/Attribute.h"
29	#include "SynTree/Statement.h"
30	#include "SynTree/Initializer.h"
31	#include "SynTree/Mutator.h"
32	#include "SymTab/Indexer.h"
33	#include "GenPoly/PolyMutator.h"
34	#include "SynTree/AddStmtVisitor.h"
35	#include "CodeGen/GenType.h" // for warnings
36
37	bool ctordtorp = false;
38	bool ctorp = false;
39	bool cpctorp = false;
40	bool dtorp = false;
41	#define PRINT( text ) if ( ctordtorp ) { text }
42	#define CP_CTOR_PRINT( text ) if ( ctordtorp \|\| cpctorp ) { text }
43	#define DTOR_PRINT( text ) if ( ctordtorp \|\| dtorp ) { text }
44
45	namespace InitTweak {
46	namespace {
47	const std::list<Label> noLabels;
48	const std::list<Expression*> noDesignators;
49
50	class InsertImplicitCalls : public GenPoly::PolyMutator {
51	public:
52	/// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which
53	/// function calls need their parameters to be copy constructed
54	static void insert( std::list< Declaration * > & translationUnit );
55
56	virtual Expression * mutate( ApplicationExpr * appExpr );
57	};
58
59	class ResolveCopyCtors : public SymTab::Indexer {
60	public:
61	/// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr,
62	/// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
63	/// arguments and return value temporaries
64	static void resolveImplicitCalls( std::list< Declaration * > & translationUnit );
65
66	virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr );
67
68	/// create and resolve ctor/dtor expression: fname(var, [cpArg])
69	ApplicationExpr * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
70	/// true if type does not need to be copy constructed to ensure correctness
71	bool skipCopyConstruct( Type * );
72	private:
73	TypeSubstitution * env;
74	};
75
76	/// collects constructed object decls - used as a base class
77	class ObjDeclCollector : public AddStmtVisitor {
78	public:
79	typedef AddStmtVisitor Parent;
80	using Parent::visit;
81	typedef std::set< ObjectDecl * > ObjectSet;
82	virtual void visit( CompoundStmt *compoundStmt );
83	virtual void visit( DeclStmt *stmt );
84	protected:
85	ObjectSet curVars;
86	};
87
88	// debug
89	struct printSet {
90	typedef ObjDeclCollector::ObjectSet ObjectSet;
91	printSet( const ObjectSet & objs ) : objs( objs ) {}
92	const ObjectSet & objs;
93	};
94	std::ostream & operator<<( std::ostream & out, const printSet & set) {
95	out << "{ ";
96	for ( ObjectDecl * obj : set.objs ) {
97	out << obj->get_name() << ", " ;
98	} // for
99	out << " }";
100	return out;
101	}
102
103	class LabelFinder : public ObjDeclCollector {
104	public:
105	typedef ObjDeclCollector Parent;
106	typedef std::map< Label, ObjectSet > LabelMap;
107	// map of Label -> live variables at that label
108	LabelMap vars;
109
110	void handleStmt( Statement * stmt );
111
112	// xxx - This needs to be done better.
113	// allow some generalization among different kinds of nodes with with similar parentage (e.g. all
114	// expressions, all statements, etc.) important to have this to provide a single entry point so that as new
115	// subclasses are added, there is only one place that the code has to be updated, rather than ensure that
116	// every specialized class knows about every new kind of statement that might be added.
117	virtual void visit( CompoundStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
118	virtual void visit( ExprStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
119	virtual void visit( AsmStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
120	virtual void visit( IfStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
121	virtual void visit( WhileStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
122	virtual void visit( ForStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
123	virtual void visit( SwitchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
124	virtual void visit( CaseStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
125	virtual void visit( BranchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
126	virtual void visit( ReturnStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
127	virtual void visit( TryStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
128	virtual void visit( CatchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
129	virtual void visit( FinallyStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
130	virtual void visit( NullStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
131	virtual void visit( DeclStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
132	virtual void visit( ImplicitCtorDtorStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
133	};
134
135	class InsertDtors : public ObjDeclCollector {
136	public:
137	/// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
138	/// (currently by FixInit)
139	static void insert( std::list< Declaration * > & translationUnit );
140
141	typedef ObjDeclCollector Parent;
142	typedef std::list< ObjectDecl * > OrderedDecls;
143	typedef std::list< OrderedDecls > OrderedDeclsStack;
144
145	InsertDtors( LabelFinder & finder ) : labelVars( finder.vars ) {}
146
147	virtual void visit( ObjectDecl * objDecl );
148
149	virtual void visit( CompoundStmt * compoundStmt );
150	virtual void visit( ReturnStmt * returnStmt );
151	virtual void visit( BranchStmt * stmt );
152	private:
153	void handleGoto( BranchStmt * stmt );
154
155	LabelFinder::LabelMap & labelVars;
156	OrderedDeclsStack reverseDeclOrder;
157	};
158
159	class FixInit : public GenPoly::PolyMutator {
160	public:
161	/// expand each object declaration to use its constructor after it is declared.
162	static void fixInitializers( std::list< Declaration * > &translationUnit );
163
164	virtual DeclarationWithType * mutate( ObjectDecl *objDecl );
165
166	std::list< Declaration * > staticDtorDecls;
167	};
168
169	class FixCopyCtors : public GenPoly::PolyMutator {
170	public:
171	/// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors, call expression,
172	/// and destructors
173	static void fixCopyCtors( std::list< Declaration * > &translationUnit );
174
175	virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr );
176	};
177
178	class WarnStructMembers : public Visitor {
179	public:
180	typedef Visitor Parent;
181	/// warn if a user-defined constructor or destructor is missing calls for
182	/// a struct member or if a member is used before constructed
183	static void warnings( std::list< Declaration * > & translationUnit );
184
185	virtual void visit( FunctionDecl * funcDecl );
186
187	virtual void visit( MemberExpr * memberExpr );
188	virtual void visit( ApplicationExpr * appExpr );
189
190	private:
191	void handleFirstParam( Expression * firstParam );
192
193	FunctionDecl * function = 0;
194	std::set< DeclarationWithType * > unhandled;
195	ObjectDecl * thisParam = 0;
196	};
197	} // namespace
198
199	void fix( std::list< Declaration * > & translationUnit, const std::string & filename, bool inLibrary ) {
200	// fixes ConstructorInit for global variables. should happen before fixInitializers.
201	InitTweak::fixGlobalInit( translationUnit, filename, inLibrary );
202
203	InsertImplicitCalls::insert( translationUnit );
204	ResolveCopyCtors::resolveImplicitCalls( translationUnit );
205	InsertDtors::insert( translationUnit );
206	FixInit::fixInitializers( translationUnit );
207
208	// FixCopyCtors must happen after FixInit, so that destructors are placed correctly
209	FixCopyCtors::fixCopyCtors( translationUnit );
210
211	WarnStructMembers::warnings( translationUnit );
212	}
213
214	namespace {
215	void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
216	InsertImplicitCalls inserter;
217	mutateAll( translationUnit, inserter );
218	}
219
220	void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
221	ResolveCopyCtors resolver;
222	acceptAll( translationUnit, resolver );
223	}
224
225	void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
226	FixInit fixer;
227
228	// can't use mutateAll, because need to insert declarations at top-level
229	// can't use DeclMutator, because sometimes need to insert IfStmt, etc.
230	SemanticError errors;
231	for ( std::list< Declaration * >::iterator i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
232	try {
233	i = maybeMutate( i, fixer );
234	translationUnit.splice( i, fixer.staticDtorDecls );
235	} catch( SemanticError &e ) {
236	errors.append( e );
237	} // try
238	} // for
239	if ( ! errors.isEmpty() ) {
240	throw errors;
241	} // if
242	}
243
244	void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
245	LabelFinder finder;
246	InsertDtors inserter( finder );
247	acceptAll( translationUnit, finder );
248	acceptAll( translationUnit, inserter );
249	}
250
251	void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
252	FixCopyCtors fixer;
253	mutateAll( translationUnit, fixer );
254	}
255
256	void WarnStructMembers::warnings( std::list< Declaration * > & translationUnit ) {
257	if ( true ) { // fix this condition to skip this pass if warnings aren't enabled
258	WarnStructMembers warner;
259	acceptAll( translationUnit, warner );
260	}
261	}
262
263	Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
264	appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
265	assert( appExpr );
266
267	if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
268	if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
269	// optimization: don't need to copy construct in order to call intrinsic functions
270	return appExpr;
271	} else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
272	FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
273	assert( ftype );
274	if ( (isConstructor( funcDecl->get_name() ) \|\| funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
275	Type * t1 = ftype->get_parameters().front()->get_type();
276	Type * t2 = ftype->get_parameters().back()->get_type();
277	PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
278	assert( ptrType );
279
280	if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
281	// optimization: don't need to copy construct in order to call a copy constructor or
282	// assignment operator
283	return appExpr;
284	} // if
285	} else if ( isDestructor( funcDecl->get_name() ) ) {
286	// correctness: never copy construct arguments to a destructor
287	return appExpr;
288	} // if
289	} // if
290	} // if
291	CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
292
293	// wrap each function call so that it is easy to identify nodes that have to be copy constructed
294	ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
295	// save the type substitution onto the new node so that it is easy to find.
296	// Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
297	// The substitution is needed to obtain the type of temporary variables so that copy constructor
298	// calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
299	// copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
300	// saves the environment, or compute the types of temporaries here, but it's much simpler to
301	// save the environment here, and more cohesive to compute temporary variables and resolve copy
302	// constructor calls together.
303	assert( env );
304	expr->set_env( env );
305	return expr;
306	}
307
308	bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
309	return dynamic_cast< VarArgsType * >( type ) \|\| GenPoly::getFunctionType( type );
310	}
311
312	ApplicationExpr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
313	assert( var );
314	UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
315	untyped->get_args().push_back( new AddressExpr( new VariableExpr( var ) ) );
316	if (cpArg) untyped->get_args().push_back( cpArg->clone() );
317
318	// resolve copy constructor
319	// should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
320	// (VariableExpr and already resolved expression)
321	CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
322	ApplicationExpr * resolved = dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untyped, *this ) );
323	if ( resolved->get_env() ) {
324	env->add( *resolved->get_env() );
325	} // if
326
327	assert( resolved );
328	delete untyped;
329	return resolved;
330	}
331
332	void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
333	static UniqueName tempNamer("_tmp_cp");
334	static UniqueName retNamer("_tmp_cp_ret");
335
336	CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
337	Visitor::visit( impCpCtorExpr );
338	env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
339
340	ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
341
342	// take each argument and attempt to copy construct it.
343	for ( Expression * & arg : appExpr->get_args() ) {
344	CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
345	// xxx - need to handle tuple arguments
346	assert( ! arg->get_results().empty() );
347	Type * result = arg->get_results().front();
348	if ( skipCopyConstruct( result ) ) continue; // skip certain non-copyable types
349	// type may involve type variables, so apply type substitution to get temporary variable's actual type
350	result = result->clone();
351	impCpCtorExpr->get_env()->apply( result );
352	ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
353	tmp->get_type()->set_isConst( false );
354
355	// create and resolve copy constructor
356	CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
357	ApplicationExpr * cpCtor = makeCtorDtor( "?{}", tmp, arg );
358
359	// if the chosen constructor is intrinsic, the copy is unnecessary, so
360	// don't create the temporary and don't call the copy constructor
361	VariableExpr * function = dynamic_cast< VariableExpr * >( cpCtor->get_function() );
362	assert( function );
363	if ( function->get_var()->get_linkage() != LinkageSpec::Intrinsic ) {
364	// replace argument to function call with temporary
365	arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
366	impCpCtorExpr->get_tempDecls().push_back( tmp );
367	impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
368	} // if
369	} // for
370
371	// each return value from the call needs to be connected with an ObjectDecl at the call site, which is
372	// initialized with the return value and is destructed later
373	// xxx - handle multiple return values
374	ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
375	// xxx - is this right? callExpr may not have the right environment, because it was attached at a higher
376	// level. Trying to pass that environment along.
377	callExpr->set_env( impCpCtorExpr->get_env()->clone() );
378	for ( Type * result : appExpr->get_results() ) {
379	result = result->clone();
380	impCpCtorExpr->get_env()->apply( result );
381	ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
382	ret->get_type()->set_isConst( false );
383	impCpCtorExpr->get_returnDecls().push_back( ret );
384	CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
385	impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
386	} // for
387	CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
388	}
389
390
391	Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
392	CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
393
394	impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
395	assert( impCpCtorExpr );
396
397	std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
398	std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
399	std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
400
401	// add all temporary declarations and their constructors
402	for ( ObjectDecl * obj : tempDecls ) {
403	stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
404	} // for
405	for ( ObjectDecl * obj : returnDecls ) {
406	stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
407	} // for
408
409	// add destructors after current statement
410	for ( Expression * dtor : dtors ) {
411	stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
412	} // for
413
414	// xxx - update to work with multiple return values
415	ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
416	Expression * callExpr = impCpCtorExpr->get_callExpr();
417
418	CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
419
420	// detach fields from wrapper node so that it can be deleted without deleting too much
421	dtors.clear();
422	tempDecls.clear();
423	returnDecls.clear();
424	impCpCtorExpr->set_callExpr( NULL );
425	impCpCtorExpr->set_env( NULL );
426	delete impCpCtorExpr;
427
428	if ( returnDecl ) {
429	UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
430	assign->get_args().push_back( new VariableExpr( returnDecl ) );
431	assign->get_args().push_back( callExpr );
432	// know the result type of the assignment is the type of the LHS (minus the pointer), so
433	// add that onto the assignment expression so that later steps have the necessary information
434	assign->add_result( returnDecl->get_type()->clone() );
435
436	Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
437	if ( callExpr->get_results().front()->get_isLvalue() ) {
438	// lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
439	// non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
440	// type of the return temporary from T to T* to properly capture the return value. Then dereference
441	// the result of the comma expression, since the lvalue returning call was originally wrapped with
442	// an AddressExpr. Effectively, this turns
443	// lvalue T f();
444	// &*f()
445	// into
446	// T * tmp_cp_retN;
447	// tmp_cp_ret_N = &(tmp_cp_ret_N = &f(), tmp_cp_ret);
448	// which work out in terms of types, but is pretty messy. It would be nice to find a better way.
449	assign->get_args().back() = new AddressExpr( assign->get_args().back() );
450
451	Type * resultType = returnDecl->get_type()->clone();
452	returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
453	UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
454	deref->get_args().push_back( retExpr );
455	deref->add_result( resultType );
456	retExpr = deref;
457	} // if
458	// xxx - might need to set env on retExpr...
459	// retExpr->set_env( env->clone() );
460	return retExpr;
461	} else {
462	return callExpr;
463	} // if
464	}
465
466	DeclarationWithType FixInit::mutate( ObjectDecl objDecl ) {
467	// first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
468	// is removed from the ObjectDecl
469	objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
470
471	if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
472	// a decision should have been made by the resolver, so ctor and init are not both non-NULL
473	assert( ! ctorInit->get_ctor() \|\| ! ctorInit->get_init() );
474	if ( Statement * ctor = ctorInit->get_ctor() ) {
475	if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
476	// originally wanted to take advantage of gcc nested functions, but
477	// we get memory errors with this approach. To remedy this, the static
478	// variable is hoisted when the destructor needs to be called.
479	//
480	// generate:
481	// static T __objName_static_varN;
482	// void __objName_dtor_atexitN() {
483	// __dtor__...;
484	// }
485	// int f(...) {
486	// ...
487	// static bool __objName_uninitialized = true;
488	// if (__objName_uninitialized) {
489	// __ctor(__objName);
490	// __objName_uninitialized = false;
491	// atexit(__objName_dtor_atexitN);
492	// }
493	// ...
494	// }
495
496	static UniqueName dtorCallerNamer( "_dtor_atexit" );
497
498	// static bool __objName_uninitialized = true
499	BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
500	SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
501	ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
502	isUninitializedVar->fixUniqueId();
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, setTrue ) );
514
515	// put it all together
516	IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
517	stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
518	stmtsToAddAfter.push_back( ifStmt );
519
520	if ( ctorInit->get_dtor() ) {
521	// if the object has a non-trivial destructor, have to
522	// hoist it and the object into the global space and
523	// call the destructor function with atexit.
524
525	Statement * dtorStmt = ctorInit->get_dtor()->clone();
526
527	// void __objName_dtor_atexitN(...) {...}
528	FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + dtorCallerNamer.newName(), DeclarationNode::Static, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
529	dtorCaller->fixUniqueId();
530	dtorCaller->get_statements()->get_kids().push_back( dtorStmt );
531
532	// atexit(dtor_atexit);
533	UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
534	callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
535
536	body.push_back( new ExprStmt( noLabels, callAtexit ) );
537
538	// hoist variable and dtor caller decls to list of decls that will be added into global scope
539	staticDtorDecls.push_back( objDecl );
540	staticDtorDecls.push_back( dtorCaller );
541
542	// need to rename object uniquely since it now appears
543	// at global scope and there could be multiple function-scoped
544	// static variables with the same name in different functions.
545	static UniqueName staticNamer( "_static_var" );
546	objDecl->set_mangleName( objDecl->get_mangleName() + staticNamer.newName() );
547
548	objDecl->set_init( NULL );
549	ctorInit->set_ctor( NULL );
550	delete ctorInit;
551
552	// xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope
553	// create a new object which is never used
554	static UniqueName dummyNamer( "_dummy" );
555	ObjectDecl * dummy = new ObjectDecl( dummyNamer.newName(), DeclarationNode::Static, LinkageSpec::Cforall, 0, new PointerType( Type::Qualifiers(), new VoidType( Type::Qualifiers() ) ), 0, std::list< Attribute * >{ new Attribute("unused") } );
556	return dummy;
557	}
558	} else {
559	stmtsToAddAfter.push_back( ctor );
560	} // if
561	objDecl->set_init( NULL );
562	ctorInit->set_ctor( NULL );
563	} else if ( Initializer * init = ctorInit->get_init() ) {
564	objDecl->set_init( init );
565	ctorInit->set_init( NULL );
566	} else {
567	// no constructor and no initializer, which is okay
568	objDecl->set_init( NULL );
569	} // if
570	delete ctorInit;
571	} // if
572	return objDecl;
573	}
574
575	void ObjDeclCollector::visit( CompoundStmt *compoundStmt ) {
576	std::set< ObjectDecl * > prevVars = curVars;
577	Parent::visit( compoundStmt );
578	curVars = prevVars;
579	}
580
581	void ObjDeclCollector::visit( DeclStmt *stmt ) {
582	// keep track of all variables currently in scope
583	if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
584	curVars.insert( objDecl );
585	} // if
586	Parent::visit( stmt );
587	}
588
589	void LabelFinder::handleStmt( Statement * stmt ) {
590	// for each label, remember the variables in scope at that label.
591	for ( Label l : stmt->get_labels() ) {
592	vars[l] = curVars;
593	} // for
594	}
595
596	template<typename Iterator, typename OutputIterator>
597	void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
598	for ( Iterator it = begin ; it != end ; ++it ) {
599	// extract destructor statement from the object decl and insert it into the output. Note that this is
600	// only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
601	// calls an intrinsic dtor then the call must (and will) still be generated since the argument may
602	// contain side effects.
603	ObjectDecl * objDecl = *it;
604	ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
605	assert( ctorInit && ctorInit->get_dtor() );
606	*out++ = ctorInit->get_dtor()->clone();
607	} // for
608	}
609
610	void InsertDtors::visit( ObjectDecl * objDecl ) {
611	// remember non-static destructed objects so that their destructors can be inserted later
612	if ( objDecl->get_storageClass() != DeclarationNode::Static ) {
613	if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
614	// a decision should have been made by the resolver, so ctor and init are not both non-NULL
615	assert( ! ctorInit->get_ctor() \|\| ! ctorInit->get_init() );
616	Statement * dtor = ctorInit->get_dtor();
617	if ( dtor && ! isIntrinsicSingleArgCallStmt( dtor ) ) {
618	// don't need to call intrinsic dtor, because it does nothing, but
619	// non-intrinsic dtors must be called
620	reverseDeclOrder.front().push_front( objDecl );
621	} // if
622	} // if
623	} // if
624	Parent::visit( objDecl );
625	}
626
627	void InsertDtors::visit( CompoundStmt * compoundStmt ) {
628	// visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
629	// when block is left, just the destructors associated with variables defined in this block, so push a new
630	// list to the top of the stack so that we can differentiate scopes
631	reverseDeclOrder.push_front( OrderedDecls() );
632	Parent::visit( compoundStmt );
633
634	// add destructors for the current scope that we're exiting
635	std::list< Statement * > & statements = compoundStmt->get_kids();
636	insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
637	reverseDeclOrder.pop_front();
638	}
639
640	void InsertDtors::visit( ReturnStmt * returnStmt ) {
641	// return exits all scopes, so dump destructors for all scopes
642	for ( OrderedDecls & od : reverseDeclOrder ) {
643	insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
644	} // for
645	}
646
647	// Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
648	// BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
649	// at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
650	// of the error. See C++ Reference 6.6 Jump Statements for details.
651	void InsertDtors::handleGoto( BranchStmt * stmt ) {
652	assert( stmt->get_target() != "" && "BranchStmt missing a label" );
653	// S_L = lvars = set of objects in scope at label definition
654	// S_G = curVars = set of objects in scope at goto statement
655	ObjectSet & lvars = labelVars[ stmt->get_target() ];
656
657	DTOR_PRINT(
658	std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
659	std::cerr << "S_G = " << printSet( curVars ) << std::endl;
660	std::cerr << "S_L = " << printSet( lvars ) << std::endl;
661	)
662
663	ObjectSet diff;
664	// S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
665	std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
666	DTOR_PRINT(
667	std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
668	)
669	if ( ! diff.empty() ) {
670	throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
671	} // if
672	// S_G-S_L results in set of objects that must be destructed
673	diff.clear();
674	std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
675	DTOR_PRINT(
676	std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
677	)
678	if ( ! diff.empty() ) {
679	// go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
680	OrderedDecls ordered;
681	for ( OrderedDecls & rdo : reverseDeclOrder ) {
682	// add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
683	copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
684	} // for
685	insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
686	} // if
687	}
688
689	void InsertDtors::visit( BranchStmt * stmt ) {
690	switch( stmt->get_type() ) {
691	case BranchStmt::Continue:
692	case BranchStmt::Break:
693	// could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
694	// always be empty), but it serves as a small sanity check.
695	case BranchStmt::Goto:
696	handleGoto( stmt );
697	break;
698	default:
699	assert( false );
700	} // switch
701	}
702
703	bool checkWarnings( FunctionDecl * funcDecl ) {
704	// only check for warnings if the current function is a user-defined
705	// constructor or destructor
706	if ( ! funcDecl ) return false;
707	if ( ! funcDecl->get_statements() ) return false;
708	return isCtorDtor( funcDecl->get_name() ) && ! LinkageSpec::isOverridable( funcDecl->get_linkage() );
709	}
710
711	void WarnStructMembers::visit( FunctionDecl * funcDecl ) {
712	WarnStructMembers old = *this;
713	*this = WarnStructMembers();
714
715	function = funcDecl;
716	if ( checkWarnings( funcDecl ) ) {
717	FunctionType * type = funcDecl->get_functionType();
718	assert( ! type->get_parameters().empty() );
719	thisParam = safe_dynamic_cast< ObjectDecl * >( type->get_parameters().front() );
720	PointerType * ptrType = safe_dynamic_cast< PointerType * > ( thisParam->get_type() );
721	StructInstType * structType = dynamic_cast< StructInstType * >( ptrType->get_base() );
722	if ( structType ) {
723	StructDecl * structDecl = structType->get_baseStruct();
724	for ( Declaration * member : structDecl->get_members() ) {
725	if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
726	// record all of the struct type's members that need to be constructed or
727	// destructed by the end of the function
728	unhandled.insert( field );
729	}
730	}
731	}
732	}
733	Parent::visit( funcDecl );
734
735	for ( DeclarationWithType * member : unhandled ) {
736	// emit a warning for each unhandled member
737	warn( "in ", CodeGen::genType( function->get_functionType(), function->get_name(), false ), ", member ", member->get_name(), " may not have been ", isConstructor( funcDecl->get_name() ) ? "constructed" : "destructed" );
738	}
739
740	*this = old;
741	}
742
743	void WarnStructMembers::visit( ApplicationExpr * appExpr ) {
744	if ( ! checkWarnings( function ) ) return;
745
746	std::string fname = getFunctionName( appExpr );
747	if ( fname == function->get_name() ) {
748	// call to same kind of function
749	Expression * firstParam = appExpr->get_args().front();
750
751	if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( firstParam ) ) {
752	// if calling another constructor on thisParam, assume that function handles
753	// all members - if it doesn't a warning will appear in that function.
754	if ( varExpr->get_var() == thisParam ) {
755	unhandled.clear();
756	}
757	} else {
758	// if first parameter is a member expression then
759	// remove the member from unhandled set.
760	handleFirstParam( firstParam );
761	}
762	} else if ( fname == "?=?" && isIntrinsicCallExpr( appExpr ) ) {
763	// forgive use of intrinsic assignment to construct, since instrinsic constructors
764	// codegen as assignment anyway.
765	assert( appExpr->get_args().size() == 2 );
766	handleFirstParam( appExpr->get_args().front() );
767	}
768
769	Parent::visit( appExpr );
770	}
771
772	void WarnStructMembers::handleFirstParam( Expression * firstParam ) {
773	using namespace std;
774	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( firstParam ) ) {
775	if ( MemberExpr * memberExpr = dynamic_cast< MemberExpr * >( addrExpr->get_arg() ) ) {
776	if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
777	if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
778	if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
779	if ( varExpr->get_var() == thisParam ) {
780	unhandled.erase( memberExpr->get_member() );
781	}
782	}
783	}
784	}
785	}
786	}
787	}
788
789	void WarnStructMembers::visit( MemberExpr * memberExpr ) {
790	if ( ! checkWarnings( function ) ) return;
791	if ( ! isConstructor( function->get_name() ) ) return;
792
793	if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
794	if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
795	if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
796	if ( varExpr->get_var() == thisParam ) {
797	if ( unhandled.count( memberExpr->get_member() ) ) {
798	// emit a warning because a member was used before it was constructed
799	warn( "in ", CodeGen::genType( function->get_functionType(), function->get_name(), false ), ", member ", memberExpr->get_member()->get_name(), " used before being constructed" );
800	}
801	}
802	}
803	}
804	}
805	Parent::visit( memberExpr );
806	}
807	} // namespace
808	} // namespace InitTweak
809
810	// Local Variables: //
811	// tab-width: 4 //
812	// mode: c++ //
813	// compile-command: "make install" //
814	// End: //

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