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source: src/InitTweak/FixInit.cc @ 8f7cea1

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

Last change on this file since 8f7cea1 was b6fe7e6, checked in by Rob Schluntz <rschlunt@…>, 8 years ago
make constructor expressions work, fix bug with using the wrong TypeEnvironment? on member exprs, remove many unnecessary ctor/dtors from the prelude
Property mode set to `100644`
File size: 41.4 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 "SymTab/Autogen.h"
34	#include "GenPoly/PolyMutator.h"
35	#include "GenPoly/DeclMutator.h"
36	#include "SynTree/AddStmtVisitor.h"
37	#include "CodeGen/GenType.h" // for warnings
38
39	bool ctordtorp = false;
40	bool ctorp = false;
41	bool cpctorp = false;
42	bool dtorp = false;
43	#define PRINT( text ) if ( ctordtorp ) { text }
44	#define CP_CTOR_PRINT( text ) if ( ctordtorp \|\| cpctorp ) { text }
45	#define DTOR_PRINT( text ) if ( ctordtorp \|\| dtorp ) { text }
46
47	namespace InitTweak {
48	namespace {
49	const std::list<Label> noLabels;
50	const std::list<Expression*> noDesignators;
51
52	class InsertImplicitCalls : public GenPoly::PolyMutator {
53	public:
54	/// wrap function application expressions as ImplicitCopyCtorExpr nodes so that it is easy to identify which
55	/// function calls need their parameters to be copy constructed
56	static void insert( std::list< Declaration * > & translationUnit );
57
58	virtual Expression * mutate( ApplicationExpr * appExpr );
59	};
60
61	class ResolveCopyCtors : public SymTab::Indexer {
62	public:
63	/// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr,
64	/// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
65	/// arguments and return value temporaries
66	static void resolveImplicitCalls( std::list< Declaration * > & translationUnit );
67
68	virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr );
69
70	/// create and resolve ctor/dtor expression: fname(var, [cpArg])
71	ApplicationExpr * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
72	/// true if type does not need to be copy constructed to ensure correctness
73	bool skipCopyConstruct( Type * );
74	private:
75	TypeSubstitution * env;
76	};
77
78	/// collects constructed object decls - used as a base class
79	class ObjDeclCollector : public AddStmtVisitor {
80	public:
81	typedef AddStmtVisitor Parent;
82	using Parent::visit;
83	typedef std::set< ObjectDecl * > ObjectSet;
84	virtual void visit( CompoundStmt *compoundStmt );
85	virtual void visit( DeclStmt *stmt );
86	protected:
87	ObjectSet curVars;
88	};
89
90	// debug
91	struct printSet {
92	typedef ObjDeclCollector::ObjectSet ObjectSet;
93	printSet( const ObjectSet & objs ) : objs( objs ) {}
94	const ObjectSet & objs;
95	};
96	std::ostream & operator<<( std::ostream & out, const printSet & set) {
97	out << "{ ";
98	for ( ObjectDecl * obj : set.objs ) {
99	out << obj->get_name() << ", " ;
100	} // for
101	out << " }";
102	return out;
103	}
104
105	class LabelFinder : public ObjDeclCollector {
106	public:
107	typedef ObjDeclCollector Parent;
108	typedef std::map< Label, ObjectSet > LabelMap;
109	// map of Label -> live variables at that label
110	LabelMap vars;
111
112	void handleStmt( Statement * stmt );
113
114	// xxx - This needs to be done better.
115	// allow some generalization among different kinds of nodes with with similar parentage (e.g. all
116	// expressions, all statements, etc.) important to have this to provide a single entry point so that as new
117	// subclasses are added, there is only one place that the code has to be updated, rather than ensure that
118	// every specialized class knows about every new kind of statement that might be added.
119	virtual void visit( CompoundStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
120	virtual void visit( ExprStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
121	virtual void visit( AsmStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
122	virtual void visit( IfStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
123	virtual void visit( WhileStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
124	virtual void visit( ForStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
125	virtual void visit( SwitchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
126	virtual void visit( CaseStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
127	virtual void visit( BranchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
128	virtual void visit( ReturnStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
129	virtual void visit( TryStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
130	virtual void visit( CatchStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
131	virtual void visit( FinallyStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
132	virtual void visit( NullStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
133	virtual void visit( DeclStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
134	virtual void visit( ImplicitCtorDtorStmt *stmt ) { handleStmt( stmt ); return Parent::visit( stmt ); }
135	};
136
137	class InsertDtors : public ObjDeclCollector {
138	public:
139	/// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
140	/// (currently by FixInit)
141	static void insert( std::list< Declaration * > & translationUnit );
142
143	typedef ObjDeclCollector Parent;
144	typedef std::list< ObjectDecl * > OrderedDecls;
145	typedef std::list< OrderedDecls > OrderedDeclsStack;
146
147	InsertDtors( LabelFinder & finder ) : labelVars( finder.vars ) {}
148
149	virtual void visit( ObjectDecl * objDecl );
150
151	virtual void visit( CompoundStmt * compoundStmt );
152	virtual void visit( ReturnStmt * returnStmt );
153	virtual void visit( BranchStmt * stmt );
154	private:
155	void handleGoto( BranchStmt * stmt );
156
157	LabelFinder::LabelMap & labelVars;
158	OrderedDeclsStack reverseDeclOrder;
159	};
160
161	class FixInit : public GenPoly::PolyMutator {
162	public:
163	/// expand each object declaration to use its constructor after it is declared.
164	static void fixInitializers( std::list< Declaration * > &translationUnit );
165
166	virtual DeclarationWithType * mutate( ObjectDecl *objDecl );
167
168	std::list< Declaration * > staticDtorDecls;
169	};
170
171	class FixCopyCtors : public GenPoly::PolyMutator {
172	public:
173	/// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors, call expression,
174	/// and destructors
175	static void fixCopyCtors( std::list< Declaration * > &translationUnit );
176
177	virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr );
178	};
179
180	class GenStructMemberCalls : public SymTab::Indexer {
181	public:
182	typedef Indexer Parent;
183	/// generate default/copy ctor and dtor calls for user-defined struct ctor/dtors
184	/// for any member that is missing a corresponding ctor/dtor call.
185	/// error if a member is used before constructed
186	static void generate( std::list< Declaration * > & translationUnit );
187
188	virtual void visit( FunctionDecl * funcDecl );
189
190	virtual void visit( MemberExpr * memberExpr );
191	virtual void visit( ApplicationExpr * appExpr );
192
193	SemanticError errors;
194	private:
195	void handleFirstParam( Expression * firstParam );
196	template< typename... Params >
197	void emit( const Params &... params );
198
199	FunctionDecl * function = 0;
200	std::set< DeclarationWithType * > unhandled, usedUninit;
201	ObjectDecl * thisParam = 0;
202	bool isCtor = false; // true if current function is a constructor
203	StructDecl * structDecl = 0;
204	};
205
206	// very simple resolver-like mutator class - used to
207	// resolve UntypedExprs that are found within newly
208	// generated constructor/destructor calls
209	class MutatingResolver : public Mutator {
210	public:
211	MutatingResolver( SymTab::Indexer & indexer ) : indexer( indexer ) {}
212
213	virtual DeclarationWithType* mutate( ObjectDecl *objectDecl );
214
215	virtual Expression* mutate( UntypedExpr *untypedExpr );
216	private:
217	SymTab::Indexer & indexer;
218	};
219
220	class FixCtorExprs : public GenPoly::DeclMutator {
221	public:
222	/// expands ConstructorExpr nodes into comma expressions, using a temporary for the first argument
223	static void fix( std::list< Declaration * > & translationUnit );
224
225	virtual Expression * mutate( ConstructorExpr * ctorExpr );
226	};
227	} // namespace
228
229	void fix( std::list< Declaration * > & translationUnit, const std::string & filename, bool inLibrary ) {
230	// fixes ConstructorInit for global variables. should happen before fixInitializers.
231	InitTweak::fixGlobalInit( translationUnit, filename, inLibrary );
232
233
234	InsertImplicitCalls::insert( translationUnit );
235	ResolveCopyCtors::resolveImplicitCalls( translationUnit );
236	InsertDtors::insert( translationUnit );
237	FixInit::fixInitializers( translationUnit );
238
239	// FixCopyCtors must happen after FixInit, so that destructors are placed correctly
240	FixCopyCtors::fixCopyCtors( translationUnit );
241
242	GenStructMemberCalls::generate( translationUnit );
243	// xxx - ctor expansion currently has to be after FixCopyCtors, because there is currently a
244	// hack in the way untyped assignments are generated, where the first argument cannot have
245	// its address taken because of the way codegeneration handles UntypedExpr vs. ApplicationExpr.
246	// Thus such assignment exprs must never pushed through expression resolution (and thus should
247	// not go through the FixCopyCtors pass), otherwise they will fail -- guaranteed.
248	// Also needs to happen after GenStructMemberCalls, since otherwise member constructors exprs
249	// don't look right, and a member can be constructed more than once.
250	FixCtorExprs::fix( translationUnit );
251	}
252
253	namespace {
254	void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
255	InsertImplicitCalls inserter;
256	mutateAll( translationUnit, inserter );
257	}
258
259	void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
260	ResolveCopyCtors resolver;
261	acceptAll( translationUnit, resolver );
262	}
263
264	void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
265	FixInit fixer;
266
267	// can't use mutateAll, because need to insert declarations at top-level
268	// can't use DeclMutator, because sometimes need to insert IfStmt, etc.
269	SemanticError errors;
270	for ( std::list< Declaration * >::iterator i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
271	try {
272	i = maybeMutate( i, fixer );
273	translationUnit.splice( i, fixer.staticDtorDecls );
274	} catch( SemanticError &e ) {
275	errors.append( e );
276	} // try
277	} // for
278	if ( ! errors.isEmpty() ) {
279	throw errors;
280	} // if
281	}
282
283	void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
284	LabelFinder finder;
285	InsertDtors inserter( finder );
286	acceptAll( translationUnit, finder );
287	acceptAll( translationUnit, inserter );
288	}
289
290	void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
291	FixCopyCtors fixer;
292	mutateAll( translationUnit, fixer );
293	}
294
295	void GenStructMemberCalls::generate( std::list< Declaration * > & translationUnit ) {
296	GenStructMemberCalls warner;
297	acceptAll( translationUnit, warner );
298
299	// visitor doesn't throw so that it can collect all errors
300	if ( ! warner.errors.isEmpty() ) {
301	throw warner.errors;
302	}
303	}
304
305	void FixCtorExprs::fix( std::list< Declaration * > & translationUnit ) {
306	FixCtorExprs fixer;
307	fixer.mutateDeclarationList( translationUnit );
308	}
309
310	Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
311	appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
312	assert( appExpr );
313
314	if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
315	if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
316	// optimization: don't need to copy construct in order to call intrinsic functions
317	return appExpr;
318	} else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
319	FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
320	assert( ftype );
321	if ( (isConstructor( funcDecl->get_name() ) \|\| funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
322	Type * t1 = ftype->get_parameters().front()->get_type();
323	Type * t2 = ftype->get_parameters().back()->get_type();
324	PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
325	assert( ptrType );
326
327	if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
328	// optimization: don't need to copy construct in order to call a copy constructor or
329	// assignment operator
330	return appExpr;
331	} // if
332	} else if ( isDestructor( funcDecl->get_name() ) ) {
333	// correctness: never copy construct arguments to a destructor
334	return appExpr;
335	} // if
336	} // if
337	} // if
338	CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
339
340	// wrap each function call so that it is easy to identify nodes that have to be copy constructed
341	ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
342	// save the type substitution onto the new node so that it is easy to find.
343	// Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
344	// The substitution is needed to obtain the type of temporary variables so that copy constructor
345	// calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
346	// copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
347	// saves the environment, or compute the types of temporaries here, but it's much simpler to
348	// save the environment here, and more cohesive to compute temporary variables and resolve copy
349	// constructor calls together.
350	assert( env );
351	expr->set_env( env );
352	return expr;
353	}
354
355	bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
356	return dynamic_cast< VarArgsType * >( type ) \|\| GenPoly::getFunctionType( type );
357	}
358
359	ApplicationExpr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
360	assert( var );
361	UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
362	untyped->get_args().push_back( new AddressExpr( new VariableExpr( var ) ) );
363	if (cpArg) untyped->get_args().push_back( cpArg->clone() );
364
365	// resolve copy constructor
366	// should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
367	// (VariableExpr and already resolved expression)
368	CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
369	ApplicationExpr * resolved = dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untyped, *this ) );
370	if ( resolved->get_env() ) {
371	env->add( *resolved->get_env() );
372	} // if
373
374	assert( resolved );
375	delete untyped;
376	return resolved;
377	}
378
379	void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
380	static UniqueName tempNamer("_tmp_cp");
381	static UniqueName retNamer("_tmp_cp_ret");
382
383	CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
384	Visitor::visit( impCpCtorExpr );
385	env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
386
387	ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
388
389	// take each argument and attempt to copy construct it.
390	for ( Expression * & arg : appExpr->get_args() ) {
391	CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
392	// xxx - need to handle tuple arguments
393	assert( ! arg->get_results().empty() );
394	Type * result = arg->get_results().front();
395	if ( skipCopyConstruct( result ) ) continue; // skip certain non-copyable types
396	// type may involve type variables, so apply type substitution to get temporary variable's actual type
397	result = result->clone();
398	impCpCtorExpr->get_env()->apply( result );
399	ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
400	tmp->get_type()->set_isConst( false );
401
402	// create and resolve copy constructor
403	CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
404	ApplicationExpr * cpCtor = makeCtorDtor( "?{}", tmp, arg );
405
406	// if the chosen constructor is intrinsic, the copy is unnecessary, so
407	// don't create the temporary and don't call the copy constructor
408	VariableExpr * function = dynamic_cast< VariableExpr * >( cpCtor->get_function() );
409	assert( function );
410	if ( function->get_var()->get_linkage() != LinkageSpec::Intrinsic ) {
411	// replace argument to function call with temporary
412	arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
413	impCpCtorExpr->get_tempDecls().push_back( tmp );
414	impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
415	} // if
416	} // for
417
418	// each return value from the call needs to be connected with an ObjectDecl at the call site, which is
419	// initialized with the return value and is destructed later
420	// xxx - handle multiple return values
421	ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
422	// xxx - is this right? callExpr may not have the right environment, because it was attached at a higher
423	// level. Trying to pass that environment along.
424	callExpr->set_env( impCpCtorExpr->get_env()->clone() );
425	for ( Type * result : appExpr->get_results() ) {
426	result = result->clone();
427	impCpCtorExpr->get_env()->apply( result );
428	ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
429	ret->get_type()->set_isConst( false );
430	impCpCtorExpr->get_returnDecls().push_back( ret );
431	CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
432	impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
433	} // for
434	CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
435	}
436
437
438	Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
439	CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
440
441	impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
442	assert( impCpCtorExpr );
443
444	std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
445	std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
446	std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
447
448	// add all temporary declarations and their constructors
449	for ( ObjectDecl * obj : tempDecls ) {
450	stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
451	} // for
452	for ( ObjectDecl * obj : returnDecls ) {
453	stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
454	} // for
455
456	// add destructors after current statement
457	for ( Expression * dtor : dtors ) {
458	stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
459	} // for
460
461	// xxx - update to work with multiple return values
462	ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
463	Expression * callExpr = impCpCtorExpr->get_callExpr();
464
465	CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
466
467	// detach fields from wrapper node so that it can be deleted without deleting too much
468	dtors.clear();
469	tempDecls.clear();
470	returnDecls.clear();
471	impCpCtorExpr->set_callExpr( NULL );
472	impCpCtorExpr->set_env( NULL );
473	delete impCpCtorExpr;
474
475	if ( returnDecl ) {
476	UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
477	assign->get_args().push_back( new VariableExpr( returnDecl ) );
478	assign->get_args().push_back( callExpr );
479	// know the result type of the assignment is the type of the LHS (minus the pointer), so
480	// add that onto the assignment expression so that later steps have the necessary information
481	assign->add_result( returnDecl->get_type()->clone() );
482
483	Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
484	if ( callExpr->get_results().front()->get_isLvalue() ) {
485	// lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
486	// non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
487	// type of the return temporary from T to T* to properly capture the return value. Then dereference
488	// the result of the comma expression, since the lvalue returning call was originally wrapped with
489	// an AddressExpr. Effectively, this turns
490	// lvalue T f();
491	// &*f()
492	// into
493	// T * tmp_cp_retN;
494	// tmp_cp_ret_N = &(tmp_cp_ret_N = &f(), tmp_cp_ret);
495	// which work out in terms of types, but is pretty messy. It would be nice to find a better way.
496	assign->get_args().back() = new AddressExpr( assign->get_args().back() );
497
498	Type * resultType = returnDecl->get_type()->clone();
499	returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
500	UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
501	deref->get_args().push_back( retExpr );
502	deref->add_result( resultType );
503	retExpr = deref;
504	} // if
505	retExpr->set_env( env->clone() );
506	return retExpr;
507	} else {
508	return callExpr;
509	} // if
510	}
511
512	DeclarationWithType FixInit::mutate( ObjectDecl objDecl ) {
513	// first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
514	// is removed from the ObjectDecl
515	objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
516
517	if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
518	// a decision should have been made by the resolver, so ctor and init are not both non-NULL
519	assert( ! ctorInit->get_ctor() \|\| ! ctorInit->get_init() );
520	if ( Statement * ctor = ctorInit->get_ctor() ) {
521	if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
522	// originally wanted to take advantage of gcc nested functions, but
523	// we get memory errors with this approach. To remedy this, the static
524	// variable is hoisted when the destructor needs to be called.
525	//
526	// generate:
527	// static T __objName_static_varN;
528	// void __objName_dtor_atexitN() {
529	// __dtor__...;
530	// }
531	// int f(...) {
532	// ...
533	// static bool __objName_uninitialized = true;
534	// if (__objName_uninitialized) {
535	// __ctor(__objName);
536	// __objName_uninitialized = false;
537	// atexit(__objName_dtor_atexitN);
538	// }
539	// ...
540	// }
541
542	static UniqueName dtorCallerNamer( "_dtor_atexit" );
543
544	// static bool __objName_uninitialized = true
545	BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
546	SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
547	ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
548	isUninitializedVar->fixUniqueId();
549
550	// __objName_uninitialized = false;
551	UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
552	setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
553	setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
554
555	// generate body of if
556	CompoundStmt * initStmts = new CompoundStmt( noLabels );
557	std::list< Statement * > & body = initStmts->get_kids();
558	body.push_back( ctor );
559	body.push_back( new ExprStmt( noLabels, setTrue ) );
560
561	// put it all together
562	IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
563	stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
564	stmtsToAddAfter.push_back( ifStmt );
565
566	if ( ctorInit->get_dtor() ) {
567	// if the object has a non-trivial destructor, have to
568	// hoist it and the object into the global space and
569	// call the destructor function with atexit.
570
571	Statement * dtorStmt = ctorInit->get_dtor()->clone();
572
573	// void __objName_dtor_atexitN(...) {...}
574	FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + dtorCallerNamer.newName(), DeclarationNode::Static, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
575	dtorCaller->fixUniqueId();
576	dtorCaller->get_statements()->push_back( dtorStmt );
577
578	// atexit(dtor_atexit);
579	UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
580	callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
581
582	body.push_back( new ExprStmt( noLabels, callAtexit ) );
583
584	// hoist variable and dtor caller decls to list of decls that will be added into global scope
585	staticDtorDecls.push_back( objDecl );
586	staticDtorDecls.push_back( dtorCaller );
587
588	// need to rename object uniquely since it now appears
589	// at global scope and there could be multiple function-scoped
590	// static variables with the same name in different functions.
591	// Note: it isn't sufficient to modify only the mangleName, because
592	// then subsequent Indexer passes can choke on seeing the object's name
593	// if another object has the same name and type. An unfortunate side-effect
594	// of renaming the object is that subsequent NameExprs may fail to resolve,
595	// but there shouldn't be any remaining past this point.
596	static UniqueName staticNamer( "_static_var" );
597	objDecl->set_name( objDecl->get_name() + staticNamer.newName() );
598	objDecl->set_mangleName( SymTab::Mangler::mangle( objDecl ) );
599
600	objDecl->set_init( NULL );
601	ctorInit->set_ctor( NULL );
602	delete ctorInit;
603
604	// xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope
605	// create a new object which is never used
606	static UniqueName dummyNamer( "_dummy" );
607	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") } );
608	return dummy;
609	}
610	} else {
611	stmtsToAddAfter.push_back( ctor );
612	} // if
613	objDecl->set_init( NULL );
614	ctorInit->set_ctor( NULL );
615	} else if ( Initializer * init = ctorInit->get_init() ) {
616	objDecl->set_init( init );
617	ctorInit->set_init( NULL );
618	} else {
619	// no constructor and no initializer, which is okay
620	objDecl->set_init( NULL );
621	} // if
622	delete ctorInit;
623	} // if
624	return objDecl;
625	}
626
627	void ObjDeclCollector::visit( CompoundStmt *compoundStmt ) {
628	std::set< ObjectDecl * > prevVars = curVars;
629	Parent::visit( compoundStmt );
630	curVars = prevVars;
631	}
632
633	void ObjDeclCollector::visit( DeclStmt *stmt ) {
634	// keep track of all variables currently in scope
635	if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
636	curVars.insert( objDecl );
637	} // if
638	Parent::visit( stmt );
639	}
640
641	void LabelFinder::handleStmt( Statement * stmt ) {
642	// for each label, remember the variables in scope at that label.
643	for ( Label l : stmt->get_labels() ) {
644	vars[l] = curVars;
645	} // for
646	}
647
648	template<typename Iterator, typename OutputIterator>
649	void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
650	for ( Iterator it = begin ; it != end ; ++it ) {
651	// extract destructor statement from the object decl and insert it into the output. Note that this is
652	// only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
653	// calls an intrinsic dtor then the call must (and will) still be generated since the argument may
654	// contain side effects.
655	ObjectDecl * objDecl = *it;
656	ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
657	assert( ctorInit && ctorInit->get_dtor() );
658	*out++ = ctorInit->get_dtor()->clone();
659	} // for
660	}
661
662	void InsertDtors::visit( ObjectDecl * objDecl ) {
663	// remember non-static destructed objects so that their destructors can be inserted later
664	if ( objDecl->get_storageClass() != DeclarationNode::Static ) {
665	if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
666	// a decision should have been made by the resolver, so ctor and init are not both non-NULL
667	assert( ! ctorInit->get_ctor() \|\| ! ctorInit->get_init() );
668	Statement * dtor = ctorInit->get_dtor();
669	if ( dtor && ! isIntrinsicSingleArgCallStmt( dtor ) ) {
670	// don't need to call intrinsic dtor, because it does nothing, but
671	// non-intrinsic dtors must be called
672	reverseDeclOrder.front().push_front( objDecl );
673	} // if
674	} // if
675	} // if
676	Parent::visit( objDecl );
677	}
678
679	void InsertDtors::visit( CompoundStmt * compoundStmt ) {
680	// visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
681	// when block is left, just the destructors associated with variables defined in this block, so push a new
682	// list to the top of the stack so that we can differentiate scopes
683	reverseDeclOrder.push_front( OrderedDecls() );
684	Parent::visit( compoundStmt );
685
686	// add destructors for the current scope that we're exiting
687	std::list< Statement * > & statements = compoundStmt->get_kids();
688	insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
689	reverseDeclOrder.pop_front();
690	}
691
692	void InsertDtors::visit( ReturnStmt * returnStmt ) {
693	// return exits all scopes, so dump destructors for all scopes
694	for ( OrderedDecls & od : reverseDeclOrder ) {
695	insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
696	} // for
697	}
698
699	// Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
700	// BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
701	// at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
702	// of the error. See C++ Reference 6.6 Jump Statements for details.
703	void InsertDtors::handleGoto( BranchStmt * stmt ) {
704	assert( stmt->get_target() != "" && "BranchStmt missing a label" );
705	// S_L = lvars = set of objects in scope at label definition
706	// S_G = curVars = set of objects in scope at goto statement
707	ObjectSet & lvars = labelVars[ stmt->get_target() ];
708
709	DTOR_PRINT(
710	std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
711	std::cerr << "S_G = " << printSet( curVars ) << std::endl;
712	std::cerr << "S_L = " << printSet( lvars ) << std::endl;
713	)
714
715	ObjectSet diff;
716	// S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
717	std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
718	DTOR_PRINT(
719	std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
720	)
721	if ( ! diff.empty() ) {
722	throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
723	} // if
724	// S_G-S_L results in set of objects that must be destructed
725	diff.clear();
726	std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
727	DTOR_PRINT(
728	std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
729	)
730	if ( ! diff.empty() ) {
731	// go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
732	OrderedDecls ordered;
733	for ( OrderedDecls & rdo : reverseDeclOrder ) {
734	// add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
735	copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
736	} // for
737	insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
738	} // if
739	}
740
741	void InsertDtors::visit( BranchStmt * stmt ) {
742	switch( stmt->get_type() ) {
743	case BranchStmt::Continue:
744	case BranchStmt::Break:
745	// could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
746	// always be empty), but it serves as a small sanity check.
747	case BranchStmt::Goto:
748	handleGoto( stmt );
749	break;
750	default:
751	assert( false );
752	} // switch
753	}
754
755	bool checkWarnings( FunctionDecl * funcDecl ) {
756	// only check for warnings if the current function is a user-defined
757	// constructor or destructor
758	if ( ! funcDecl ) return false;
759	if ( ! funcDecl->get_statements() ) return false;
760	return isCtorDtor( funcDecl->get_name() ) && ! LinkageSpec::isOverridable( funcDecl->get_linkage() );
761	}
762
763	void GenStructMemberCalls::visit( FunctionDecl * funcDecl ) {
764	ValueGuard< FunctionDecl * > oldFunction( funcDecl );
765	ValueGuard< std::set< DeclarationWithType * > > oldUnhandled( unhandled );
766	ValueGuard< std::set< DeclarationWithType * > > oldUsedUninit( usedUninit );
767	ValueGuard< ObjectDecl * > oldThisParam( thisParam );
768	ValueGuard< bool > oldIsCtor( isCtor );
769	ValueGuard< StructDecl * > oldStructDecl( structDecl );
770
771	// need to start with fresh sets
772	unhandled.clear();
773	usedUninit.clear();
774
775	function = funcDecl;
776	isCtor = isConstructor( function->get_name() );
777	if ( checkWarnings( function ) ) {
778	FunctionType * type = function->get_functionType();
779	assert( ! type->get_parameters().empty() );
780	thisParam = safe_dynamic_cast< ObjectDecl * >( type->get_parameters().front() );
781	PointerType * ptrType = safe_dynamic_cast< PointerType * > ( thisParam->get_type() );
782	StructInstType * structType = dynamic_cast< StructInstType * >( ptrType->get_base() );
783	if ( structType ) {
784	structDecl = structType->get_baseStruct();
785	for ( Declaration * member : structDecl->get_members() ) {
786	if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
787	// record all of the struct type's members that need to be constructed or
788	// destructed by the end of the function
789	unhandled.insert( field );
790	}
791	}
792	}
793	}
794	Parent::visit( function );
795
796	// remove the unhandled objects from usedUninit, because a call is inserted
797	// to handle them - only objects that are later constructed are used uninitialized.
798	std::set< DeclarationWithType * > diff;
799	std::set_difference( usedUninit.begin(), usedUninit.end(), unhandled.begin(), unhandled.end(), std::inserter( diff, diff.begin() ) );
800	for ( DeclarationWithType * member : diff ) {
801	emit( "in ", CodeGen::genType( function->get_functionType(), function->get_name(), false ), ", field ", member->get_name(), " used before being constructed" );
802	}
803
804	if ( ! unhandled.empty() ) {
805	// need to explicitly re-add function parameters in order to resolve copy constructors
806	enterScope();
807	maybeAccept( function->get_functionType(), *this );
808
809	// need to iterate through members in reverse in order for
810	// ctor/dtor statements to come out in the right order
811	for ( Declaration * member : reverseIterate( structDecl->get_members() ) ) {
812	DeclarationWithType * field = dynamic_cast< DeclarationWithType * >( member );
813	// skip non-DWT members
814	if ( ! field ) continue;
815	// skip handled members
816	if ( ! unhandled.count( field ) ) continue;
817
818	// insert and resolve default/copy constructor call for each field that's unhandled
819	std::list< Statement * > stmt;
820	UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
821	deref->get_args().push_back( new VariableExpr( thisParam ) );
822
823	Expression * arg2 = 0;
824	if ( isCopyConstructor( function ) ) {
825	// if copy ctor, need to pass second-param-of-this-function.field
826	std::list< DeclarationWithType * > & params = function->get_functionType()->get_parameters();
827	assert( params.size() == 2 );
828	arg2 = new MemberExpr( field, new VariableExpr( params.back() ) );
829	}
830	InitExpander srcParam( arg2 );
831	SymTab::genImplicitCall( srcParam, new MemberExpr( field, deref ), function->get_name(), back_inserter( stmt ), field, isCtor );
832
833	assert( stmt.size() <= 1 );
834	if ( stmt.size() == 1 ) {
835	Statement * callStmt = stmt.front();
836
837	MutatingResolver resolver( *this );
838	try {
839	callStmt->acceptMutator( resolver );
840	if ( isCtor ) {
841	function->get_statements()->push_front( callStmt );
842	} else {
843	// destructor statements should be added at the end
844	function->get_statements()->push_back( callStmt );
845	}
846	} catch ( SemanticError & error ) {
847	emit( "in ", CodeGen::genType( function->get_functionType(), function->get_name(), false ), ", field ", field->get_name(), " not explicitly ", isCtor ? "constructed" : "destructed", " and no ", isCtor ? "default constructor" : "destructor", " found" );
848	}
849	}
850	}
851	leaveScope();
852	}
853	}
854
855	void GenStructMemberCalls::visit( ApplicationExpr * appExpr ) {
856	if ( ! checkWarnings( function ) ) return;
857
858	std::string fname = getFunctionName( appExpr );
859	if ( fname == function->get_name() ) {
860	// call to same kind of function
861	Expression * firstParam = appExpr->get_args().front();
862
863	if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( firstParam ) ) {
864	// if calling another constructor on thisParam, assume that function handles
865	// all members - if it doesn't a warning will appear in that function.
866	if ( varExpr->get_var() == thisParam ) {
867	unhandled.clear();
868	}
869	} else {
870	// if first parameter is a member expression then
871	// remove the member from unhandled set.
872	handleFirstParam( firstParam );
873	}
874	}
875
876	Parent::visit( appExpr );
877	}
878
879	void GenStructMemberCalls::handleFirstParam( Expression * firstParam ) {
880	using namespace std;
881	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( firstParam ) ) {
882	if ( MemberExpr * memberExpr = dynamic_cast< MemberExpr * >( addrExpr->get_arg() ) ) {
883	if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
884	if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
885	if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
886	if ( varExpr->get_var() == thisParam ) {
887	unhandled.erase( memberExpr->get_member() );
888	}
889	}
890	}
891	}
892	}
893	}
894	}
895
896	void GenStructMemberCalls::visit( MemberExpr * memberExpr ) {
897	if ( ! checkWarnings( function ) ) return;
898	if ( ! isCtor ) return;
899
900	if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
901	if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
902	if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
903	if ( varExpr->get_var() == thisParam ) {
904	if ( unhandled.count( memberExpr->get_member() ) ) {
905	// emit a warning because a member was used before it was constructed
906	usedUninit.insert( memberExpr->get_member() );
907	}
908	}
909	}
910	}
911	}
912	Parent::visit( memberExpr );
913	}
914
915	template< typename Visitor, typename... Params >
916	void error( Visitor & v, const Params &... params ) {
917	v.errors.append( toString( params... ) );
918	}
919
920	template< typename... Params >
921	void GenStructMemberCalls::emit( const Params &... params ) {
922	// toggle warnings vs. errors here.
923	// warn( params... );
924	error( *this, params... );
925	}
926
927	DeclarationWithType * MutatingResolver::mutate( ObjectDecl *objectDecl ) {
928	// add object to the indexer assumes that there will be no name collisions
929	// in generated code. If this changes, add mutate methods for entities with
930	// scope and call {enter,leave}Scope explicitly.
931	objectDecl->accept( indexer );
932	return objectDecl;
933	}
934
935	Expression* MutatingResolver::mutate( UntypedExpr *untypedExpr ) {
936	return safe_dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untypedExpr, indexer ) );
937	}
938
939	Expression * FixCtorExprs::mutate( ConstructorExpr * ctorExpr ) {
940	static UniqueName tempNamer( "_tmp_ctor_expr" );
941	assert( ctorExpr->get_results().size() == 1 );
942	ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, nullptr, ctorExpr->get_results().front()->clone(), nullptr );
943	addDeclaration( tmp );
944
945	ApplicationExpr * callExpr = safe_dynamic_cast< ApplicationExpr * > ( ctorExpr->get_callExpr() );
946	TypeSubstitution * env = ctorExpr->get_env();
947	ctorExpr->set_callExpr( nullptr );
948	ctorExpr->set_env( nullptr );
949
950	Expression *& firstArg = callExpr->get_args().front();
951	UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
952	assign->get_args().push_back( new VariableExpr( tmp ) );
953	assign->get_args().push_back( firstArg );
954	cloneAll( ctorExpr->get_results(), assign->get_results() );
955	firstArg = assign;
956
957	CommaExpr * commaExpr = new CommaExpr( callExpr, new VariableExpr( tmp ) );
958	commaExpr->set_env( env );
959	delete ctorExpr;
960	return commaExpr;
961	}
962	} // namespace
963	} // namespace InitTweak
964
965	// Local Variables: //
966	// tab-width: 4 //
967	// mode: c++ //
968	// compile-command: "make install" //
969	// End: //

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