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source: src/InitTweak/FixInit.cc @ 84118d8

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 84118d8 was 62e5546, checked in by Thierry Delisle <tdelisle@…>, 7 years ago
Removed warnings when compiling with clang
Property mode set to `100644`
File size: 42.0 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 final : 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	using GenPoly::PolyMutator::mutate;
59	virtual Expression * mutate( ApplicationExpr * appExpr ) override;
60	};
61
62	class ResolveCopyCtors final : public SymTab::Indexer {
63	public:
64	/// generate temporary ObjectDecls for each argument and return value of each ImplicitCopyCtorExpr,
65	/// generate/resolve copy construction expressions for each, and generate/resolve destructors for both
66	/// arguments and return value temporaries
67	static void resolveImplicitCalls( std::list< Declaration * > & translationUnit );
68
69	using SymTab::Indexer::visit;
70	virtual void visit( ImplicitCopyCtorExpr * impCpCtorExpr ) override;
71
72	/// create and resolve ctor/dtor expression: fname(var, [cpArg])
73	ApplicationExpr * makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg = NULL );
74	/// true if type does not need to be copy constructed to ensure correctness
75	bool skipCopyConstruct( Type * );
76	private:
77	TypeSubstitution * env;
78	};
79
80	/// collects constructed object decls - used as a base class
81	class ObjDeclCollector : public AddStmtVisitor {
82	public:
83	typedef AddStmtVisitor Parent;
84	using Parent::visit;
85	typedef std::set< ObjectDecl * > ObjectSet;
86	virtual void visit( CompoundStmt *compoundStmt ) override;
87	virtual void visit( DeclStmt *stmt ) override;
88	protected:
89	ObjectSet curVars;
90	};
91
92	// debug
93	struct printSet {
94	typedef ObjDeclCollector::ObjectSet ObjectSet;
95	printSet( const ObjectSet & objs ) : objs( objs ) {}
96	const ObjectSet & objs;
97	};
98	std::ostream & operator<<( std::ostream & out, const printSet & set) {
99	out << "{ ";
100	for ( ObjectDecl * obj : set.objs ) {
101	out << obj->get_name() << ", " ;
102	} // for
103	out << " }";
104	return out;
105	}
106
107	class LabelFinder final : public ObjDeclCollector {
108	public:
109	typedef ObjDeclCollector Parent;
110	typedef std::map< Label, ObjectSet > LabelMap;
111	// map of Label -> live variables at that label
112	LabelMap vars;
113
114	void handleStmt( Statement * stmt );
115
116	// xxx - This needs to be done better.
117	// allow some generalization among different kinds of nodes with with similar parentage (e.g. all
118	// expressions, all statements, etc.) important to have this to provide a single entry point so that as new
119	// subclasses are added, there is only one place that the code has to be updated, rather than ensure that
120	// every specialized class knows about every new kind of statement that might be added.
121	using Parent::visit;
122	virtual void visit( CompoundStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
123	virtual void visit( ExprStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
124	virtual void visit( AsmStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
125	virtual void visit( IfStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
126	virtual void visit( WhileStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
127	virtual void visit( ForStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
128	virtual void visit( SwitchStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
129	virtual void visit( CaseStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
130	virtual void visit( BranchStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
131	virtual void visit( ReturnStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
132	virtual void visit( TryStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
133	virtual void visit( CatchStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
134	virtual void visit( FinallyStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
135	virtual void visit( NullStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
136	virtual void visit( DeclStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
137	virtual void visit( ImplicitCtorDtorStmt *stmt ) override { handleStmt( stmt ); return Parent::visit( stmt ); }
138	};
139
140	class InsertDtors final : public ObjDeclCollector {
141	public:
142	/// insert destructor calls at the appropriate places. must happen before CtorInit nodes are removed
143	/// (currently by FixInit)
144	static void insert( std::list< Declaration * > & translationUnit );
145
146	typedef ObjDeclCollector Parent;
147	typedef std::list< ObjectDecl * > OrderedDecls;
148	typedef std::list< OrderedDecls > OrderedDeclsStack;
149
150	InsertDtors( LabelFinder & finder ) : labelVars( finder.vars ) {}
151
152	using Parent::visit;
153
154	virtual void visit( ObjectDecl * objDecl ) override;
155
156	virtual void visit( CompoundStmt * compoundStmt ) override;
157	virtual void visit( ReturnStmt * returnStmt ) override;
158	virtual void visit( BranchStmt * stmt ) override;
159	private:
160	void handleGoto( BranchStmt * stmt );
161
162	LabelFinder::LabelMap & labelVars;
163	OrderedDeclsStack reverseDeclOrder;
164	};
165
166	class FixInit final : public GenPoly::PolyMutator {
167	public:
168	/// expand each object declaration to use its constructor after it is declared.
169	static void fixInitializers( std::list< Declaration * > &translationUnit );
170
171	using GenPoly::PolyMutator::mutate;
172	virtual DeclarationWithType * mutate( ObjectDecl *objDecl ) override;
173
174	std::list< Declaration * > staticDtorDecls;
175	};
176
177	class FixCopyCtors final : public GenPoly::PolyMutator {
178	public:
179	/// expand ImplicitCopyCtorExpr nodes into the temporary declarations, copy constructors, call expression,
180	/// and destructors
181	static void fixCopyCtors( std::list< Declaration * > &translationUnit );
182
183	using GenPoly::PolyMutator::mutate;
184	virtual Expression * mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) override;
185	};
186
187	class GenStructMemberCalls final : public SymTab::Indexer {
188	public:
189	typedef Indexer Parent;
190	/// generate default/copy ctor and dtor calls for user-defined struct ctor/dtors
191	/// for any member that is missing a corresponding ctor/dtor call.
192	/// error if a member is used before constructed
193	static void generate( std::list< Declaration * > & translationUnit );
194
195	using Parent::visit;
196
197	virtual void visit( FunctionDecl * funcDecl ) override;
198
199	virtual void visit( MemberExpr * memberExpr ) override;
200	virtual void visit( ApplicationExpr * appExpr ) override;
201
202	SemanticError errors;
203	private:
204	void handleFirstParam( Expression * firstParam );
205	template< typename... Params >
206	void emit( const Params &... params );
207
208	FunctionDecl * function = 0;
209	std::set< DeclarationWithType * > unhandled, usedUninit;
210	ObjectDecl * thisParam = 0;
211	bool isCtor = false; // true if current function is a constructor
212	StructDecl * structDecl = 0;
213	};
214
215	// very simple resolver-like mutator class - used to
216	// resolve UntypedExprs that are found within newly
217	// generated constructor/destructor calls
218	class MutatingResolver final : public Mutator {
219	public:
220	MutatingResolver( SymTab::Indexer & indexer ) : indexer( indexer ) {}
221
222	using Mutator::mutate;
223	virtual DeclarationWithType* mutate( ObjectDecl *objectDecl ) override;
224	virtual Expression* mutate( UntypedExpr *untypedExpr ) override;
225
226	private:
227	SymTab::Indexer & indexer;
228	};
229
230	class FixCtorExprs final : public GenPoly::DeclMutator {
231	public:
232	/// expands ConstructorExpr nodes into comma expressions, using a temporary for the first argument
233	static void fix( std::list< Declaration * > & translationUnit );
234
235	using GenPoly::DeclMutator::mutate;
236	virtual Expression * mutate( ConstructorExpr * ctorExpr ) override;
237	};
238	} // namespace
239
240	void fix( std::list< Declaration * > & translationUnit, const std::string & filename, bool inLibrary ) {
241	// fixes ConstructorInit for global variables. should happen before fixInitializers.
242	InitTweak::fixGlobalInit( translationUnit, filename, inLibrary );
243
244
245	InsertImplicitCalls::insert( translationUnit );
246	ResolveCopyCtors::resolveImplicitCalls( translationUnit );
247	InsertDtors::insert( translationUnit );
248	FixInit::fixInitializers( translationUnit );
249
250	// FixCopyCtors must happen after FixInit, so that destructors are placed correctly
251	FixCopyCtors::fixCopyCtors( translationUnit );
252
253	GenStructMemberCalls::generate( translationUnit );
254	// xxx - ctor expansion currently has to be after FixCopyCtors, because there is currently a
255	// hack in the way untyped assignments are generated, where the first argument cannot have
256	// its address taken because of the way codegeneration handles UntypedExpr vs. ApplicationExpr.
257	// Thus such assignment exprs must never pushed through expression resolution (and thus should
258	// not go through the FixCopyCtors pass), otherwise they will fail -- guaranteed.
259	// Also needs to happen after GenStructMemberCalls, since otherwise member constructors exprs
260	// don't look right, and a member can be constructed more than once.
261	FixCtorExprs::fix( translationUnit );
262	}
263
264	namespace {
265	void InsertImplicitCalls::insert( std::list< Declaration * > & translationUnit ) {
266	InsertImplicitCalls inserter;
267	mutateAll( translationUnit, inserter );
268	}
269
270	void ResolveCopyCtors::resolveImplicitCalls( std::list< Declaration * > & translationUnit ) {
271	ResolveCopyCtors resolver;
272	acceptAll( translationUnit, resolver );
273	}
274
275	void FixInit::fixInitializers( std::list< Declaration * > & translationUnit ) {
276	FixInit fixer;
277
278	// can't use mutateAll, because need to insert declarations at top-level
279	// can't use DeclMutator, because sometimes need to insert IfStmt, etc.
280	SemanticError errors;
281	for ( std::list< Declaration * >::iterator i = translationUnit.begin(); i != translationUnit.end(); ++i ) {
282	try {
283	i = maybeMutate( i, fixer );
284	translationUnit.splice( i, fixer.staticDtorDecls );
285	} catch( SemanticError &e ) {
286	errors.append( e );
287	} // try
288	} // for
289	if ( ! errors.isEmpty() ) {
290	throw errors;
291	} // if
292	}
293
294	void InsertDtors::insert( std::list< Declaration * > & translationUnit ) {
295	LabelFinder finder;
296	InsertDtors inserter( finder );
297	acceptAll( translationUnit, finder );
298	acceptAll( translationUnit, inserter );
299	}
300
301	void FixCopyCtors::fixCopyCtors( std::list< Declaration * > & translationUnit ) {
302	FixCopyCtors fixer;
303	mutateAll( translationUnit, fixer );
304	}
305
306	void GenStructMemberCalls::generate( std::list< Declaration * > & translationUnit ) {
307	GenStructMemberCalls warner;
308	acceptAll( translationUnit, warner );
309
310	// visitor doesn't throw so that it can collect all errors
311	if ( ! warner.errors.isEmpty() ) {
312	throw warner.errors;
313	}
314	}
315
316	void FixCtorExprs::fix( std::list< Declaration * > & translationUnit ) {
317	FixCtorExprs fixer;
318	fixer.mutateDeclarationList( translationUnit );
319	}
320
321	Expression * InsertImplicitCalls::mutate( ApplicationExpr * appExpr ) {
322	appExpr = dynamic_cast< ApplicationExpr * >( Mutator::mutate( appExpr ) );
323	assert( appExpr );
324
325	if ( VariableExpr * function = dynamic_cast< VariableExpr * > ( appExpr->get_function() ) ) {
326	if ( function->get_var()->get_linkage() == LinkageSpec::Intrinsic ) {
327	// optimization: don't need to copy construct in order to call intrinsic functions
328	return appExpr;
329	} else if ( DeclarationWithType * funcDecl = dynamic_cast< DeclarationWithType * > ( function->get_var() ) ) {
330	FunctionType * ftype = dynamic_cast< FunctionType * >( GenPoly::getFunctionType( funcDecl->get_type() ) );
331	assert( ftype );
332	if ( (isConstructor( funcDecl->get_name() ) \|\| funcDecl->get_name() == "?=?") && ftype->get_parameters().size() == 2 ) {
333	Type * t1 = ftype->get_parameters().front()->get_type();
334	Type * t2 = ftype->get_parameters().back()->get_type();
335	PointerType * ptrType = dynamic_cast< PointerType * > ( t1 );
336	assert( ptrType );
337
338	if ( ResolvExpr::typesCompatible( ptrType->get_base(), t2, SymTab::Indexer() ) ) {
339	// optimization: don't need to copy construct in order to call a copy constructor or
340	// assignment operator
341	return appExpr;
342	} // if
343	} else if ( isDestructor( funcDecl->get_name() ) ) {
344	// correctness: never copy construct arguments to a destructor
345	return appExpr;
346	} // if
347	} // if
348	} // if
349	CP_CTOR_PRINT( std::cerr << "InsertImplicitCalls: adding a wrapper " << appExpr << std::endl; )
350
351	// wrap each function call so that it is easy to identify nodes that have to be copy constructed
352	ImplicitCopyCtorExpr * expr = new ImplicitCopyCtorExpr( appExpr );
353	// save the type substitution onto the new node so that it is easy to find.
354	// Ensure it is not deleted with the ImplicitCopyCtorExpr by removing it before deletion.
355	// The substitution is needed to obtain the type of temporary variables so that copy constructor
356	// calls can be resolved. Normally this is what PolyMutator is for, but the pass that resolves
357	// copy constructor calls must be an Indexer. We could alternatively make a PolyIndexer which
358	// saves the environment, or compute the types of temporaries here, but it's much simpler to
359	// save the environment here, and more cohesive to compute temporary variables and resolve copy
360	// constructor calls together.
361	assert( env );
362	expr->set_env( env );
363	return expr;
364	}
365
366	bool ResolveCopyCtors::skipCopyConstruct( Type * type ) {
367	return dynamic_cast< VarArgsType * >( type ) \|\| GenPoly::getFunctionType( type );
368	}
369
370	ApplicationExpr * ResolveCopyCtors::makeCtorDtor( const std::string & fname, ObjectDecl * var, Expression * cpArg ) {
371	assert( var );
372	UntypedExpr * untyped = new UntypedExpr( new NameExpr( fname ) );
373	untyped->get_args().push_back( new AddressExpr( new VariableExpr( var ) ) );
374	if (cpArg) untyped->get_args().push_back( cpArg->clone() );
375
376	// resolve copy constructor
377	// should only be one alternative for copy ctor and dtor expressions, since all arguments are fixed
378	// (VariableExpr and already resolved expression)
379	CP_CTOR_PRINT( std::cerr << "ResolvingCtorDtor " << untyped << std::endl; )
380	ApplicationExpr * resolved = dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untyped, *this ) );
381	if ( resolved->get_env() ) {
382	env->add( *resolved->get_env() );
383	} // if
384
385	assert( resolved );
386	delete untyped;
387	return resolved;
388	}
389
390	void ResolveCopyCtors::visit( ImplicitCopyCtorExpr *impCpCtorExpr ) {
391	static UniqueName tempNamer("_tmp_cp");
392	static UniqueName retNamer("_tmp_cp_ret");
393
394	CP_CTOR_PRINT( std::cerr << "ResolveCopyCtors: " << impCpCtorExpr << std::endl; )
395	Visitor::visit( impCpCtorExpr );
396	env = impCpCtorExpr->get_env(); // xxx - maybe we really should just have a PolyIndexer...
397
398	ApplicationExpr * appExpr = impCpCtorExpr->get_callExpr();
399
400	// take each argument and attempt to copy construct it.
401	for ( Expression * & arg : appExpr->get_args() ) {
402	CP_CTOR_PRINT( std::cerr << "Type Substitution: " << *impCpCtorExpr->get_env() << std::endl; )
403	// xxx - need to handle tuple arguments
404	assert( ! arg->get_results().empty() );
405	Type * result = arg->get_results().front();
406	if ( skipCopyConstruct( result ) ) continue; // skip certain non-copyable types
407	// type may involve type variables, so apply type substitution to get temporary variable's actual type
408	result = result->clone();
409	impCpCtorExpr->get_env()->apply( result );
410	ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
411	tmp->get_type()->set_isConst( false );
412
413	// create and resolve copy constructor
414	CP_CTOR_PRINT( std::cerr << "makeCtorDtor for an argument" << std::endl; )
415	ApplicationExpr * cpCtor = makeCtorDtor( "?{}", tmp, arg );
416
417	// if the chosen constructor is intrinsic, the copy is unnecessary, so
418	// don't create the temporary and don't call the copy constructor
419	VariableExpr * function = dynamic_cast< VariableExpr * >( cpCtor->get_function() );
420	assert( function );
421	if ( function->get_var()->get_linkage() != LinkageSpec::Intrinsic ) {
422	// replace argument to function call with temporary
423	arg = new CommaExpr( cpCtor, new VariableExpr( tmp ) );
424	impCpCtorExpr->get_tempDecls().push_back( tmp );
425	impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", tmp ) );
426	} // if
427	} // for
428
429	// each return value from the call needs to be connected with an ObjectDecl at the call site, which is
430	// initialized with the return value and is destructed later
431	// xxx - handle multiple return values
432	ApplicationExpr * callExpr = impCpCtorExpr->get_callExpr();
433	// xxx - is this right? callExpr may not have the right environment, because it was attached at a higher
434	// level. Trying to pass that environment along.
435	callExpr->set_env( impCpCtorExpr->get_env()->clone() );
436	for ( Type * result : appExpr->get_results() ) {
437	result = result->clone();
438	impCpCtorExpr->get_env()->apply( result );
439	ObjectDecl * ret = new ObjectDecl( retNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, 0, result, 0 );
440	ret->get_type()->set_isConst( false );
441	impCpCtorExpr->get_returnDecls().push_back( ret );
442	CP_CTOR_PRINT( std::cerr << "makeCtorDtor for a return" << std::endl; )
443	impCpCtorExpr->get_dtors().push_front( makeCtorDtor( "^?{}", ret ) );
444	} // for
445	CP_CTOR_PRINT( std::cerr << "after Resolving: " << impCpCtorExpr << std::endl; )
446	}
447
448
449	Expression * FixCopyCtors::mutate( ImplicitCopyCtorExpr * impCpCtorExpr ) {
450	CP_CTOR_PRINT( std::cerr << "FixCopyCtors: " << impCpCtorExpr << std::endl; )
451
452	impCpCtorExpr = dynamic_cast< ImplicitCopyCtorExpr * >( Mutator::mutate( impCpCtorExpr ) );
453	assert( impCpCtorExpr );
454
455	std::list< ObjectDecl * > & tempDecls = impCpCtorExpr->get_tempDecls();
456	std::list< ObjectDecl * > & returnDecls = impCpCtorExpr->get_returnDecls();
457	std::list< Expression * > & dtors = impCpCtorExpr->get_dtors();
458
459	// add all temporary declarations and their constructors
460	for ( ObjectDecl * obj : tempDecls ) {
461	stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
462	} // for
463	for ( ObjectDecl * obj : returnDecls ) {
464	stmtsToAdd.push_back( new DeclStmt( noLabels, obj ) );
465	} // for
466
467	// add destructors after current statement
468	for ( Expression * dtor : dtors ) {
469	stmtsToAddAfter.push_back( new ExprStmt( noLabels, dtor ) );
470	} // for
471
472	// xxx - update to work with multiple return values
473	ObjectDecl * returnDecl = returnDecls.empty() ? NULL : returnDecls.front();
474	Expression * callExpr = impCpCtorExpr->get_callExpr();
475
476	CP_CTOR_PRINT( std::cerr << "Coming out the back..." << impCpCtorExpr << std::endl; )
477
478	// detach fields from wrapper node so that it can be deleted without deleting too much
479	dtors.clear();
480	tempDecls.clear();
481	returnDecls.clear();
482	impCpCtorExpr->set_callExpr( NULL );
483	impCpCtorExpr->set_env( NULL );
484	delete impCpCtorExpr;
485
486	if ( returnDecl ) {
487	UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
488	assign->get_args().push_back( new VariableExpr( returnDecl ) );
489	assign->get_args().push_back( callExpr );
490	// know the result type of the assignment is the type of the LHS (minus the pointer), so
491	// add that onto the assignment expression so that later steps have the necessary information
492	assign->add_result( returnDecl->get_type()->clone() );
493
494	Expression * retExpr = new CommaExpr( assign, new VariableExpr( returnDecl ) );
495	if ( callExpr->get_results().front()->get_isLvalue() ) {
496	// lvalue returning functions are funny. Lvalue.cc inserts a *? in front of any lvalue returning
497	// non-intrinsic function. Add an AddressExpr to the call to negate the derefence and change the
498	// type of the return temporary from T to T* to properly capture the return value. Then dereference
499	// the result of the comma expression, since the lvalue returning call was originally wrapped with
500	// an AddressExpr. Effectively, this turns
501	// lvalue T f();
502	// &*f()
503	// into
504	// T * tmp_cp_retN;
505	// tmp_cp_ret_N = &(tmp_cp_ret_N = &f(), tmp_cp_ret);
506	// which work out in terms of types, but is pretty messy. It would be nice to find a better way.
507	assign->get_args().back() = new AddressExpr( assign->get_args().back() );
508
509	Type * resultType = returnDecl->get_type()->clone();
510	returnDecl->set_type( new PointerType( Type::Qualifiers(), returnDecl->get_type() ) );
511	UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
512	deref->get_args().push_back( retExpr );
513	deref->add_result( resultType );
514	retExpr = deref;
515	} // if
516	retExpr->set_env( env->clone() );
517	return retExpr;
518	} else {
519	return callExpr;
520	} // if
521	}
522
523	DeclarationWithType FixInit::mutate( ObjectDecl objDecl ) {
524	// first recursively handle pieces of ObjectDecl so that they aren't missed by other visitors when the init
525	// is removed from the ObjectDecl
526	objDecl = dynamic_cast< ObjectDecl * >( Mutator::mutate( objDecl ) );
527
528	if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
529	// a decision should have been made by the resolver, so ctor and init are not both non-NULL
530	assert( ! ctorInit->get_ctor() \|\| ! ctorInit->get_init() );
531	if ( Statement * ctor = ctorInit->get_ctor() ) {
532	if ( objDecl->get_storageClass() == DeclarationNode::Static ) {
533	// originally wanted to take advantage of gcc nested functions, but
534	// we get memory errors with this approach. To remedy this, the static
535	// variable is hoisted when the destructor needs to be called.
536	//
537	// generate:
538	// static T __objName_static_varN;
539	// void __objName_dtor_atexitN() {
540	// __dtor__...;
541	// }
542	// int f(...) {
543	// ...
544	// static bool __objName_uninitialized = true;
545	// if (__objName_uninitialized) {
546	// __ctor(__objName);
547	// __objName_uninitialized = false;
548	// atexit(__objName_dtor_atexitN);
549	// }
550	// ...
551	// }
552
553	static UniqueName dtorCallerNamer( "_dtor_atexit" );
554
555	// static bool __objName_uninitialized = true
556	BasicType * boolType = new BasicType( Type::Qualifiers(), BasicType::Bool );
557	SingleInit * boolInitExpr = new SingleInit( new ConstantExpr( Constant( boolType->clone(), "1" ) ), noDesignators );
558	ObjectDecl * isUninitializedVar = new ObjectDecl( objDecl->get_mangleName() + "_uninitialized", DeclarationNode::Static, LinkageSpec::Cforall, 0, boolType, boolInitExpr );
559	isUninitializedVar->fixUniqueId();
560
561	// __objName_uninitialized = false;
562	UntypedExpr * setTrue = new UntypedExpr( new NameExpr( "?=?" ) );
563	setTrue->get_args().push_back( new VariableExpr( isUninitializedVar ) );
564	setTrue->get_args().push_back( new ConstantExpr( Constant( boolType->clone(), "0" ) ) );
565
566	// generate body of if
567	CompoundStmt * initStmts = new CompoundStmt( noLabels );
568	std::list< Statement * > & body = initStmts->get_kids();
569	body.push_back( ctor );
570	body.push_back( new ExprStmt( noLabels, setTrue ) );
571
572	// put it all together
573	IfStmt * ifStmt = new IfStmt( noLabels, new VariableExpr( isUninitializedVar ), initStmts, 0 );
574	stmtsToAddAfter.push_back( new DeclStmt( noLabels, isUninitializedVar ) );
575	stmtsToAddAfter.push_back( ifStmt );
576
577	if ( ctorInit->get_dtor() ) {
578	// if the object has a non-trivial destructor, have to
579	// hoist it and the object into the global space and
580	// call the destructor function with atexit.
581
582	Statement * dtorStmt = ctorInit->get_dtor()->clone();
583
584	// void __objName_dtor_atexitN(...) {...}
585	FunctionDecl * dtorCaller = new FunctionDecl( objDecl->get_mangleName() + dtorCallerNamer.newName(), DeclarationNode::Static, LinkageSpec::C, new FunctionType( Type::Qualifiers(), false ), new CompoundStmt( noLabels ), false, false );
586	dtorCaller->fixUniqueId();
587	dtorCaller->get_statements()->push_back( dtorStmt );
588
589	// atexit(dtor_atexit);
590	UntypedExpr * callAtexit = new UntypedExpr( new NameExpr( "atexit" ) );
591	callAtexit->get_args().push_back( new VariableExpr( dtorCaller ) );
592
593	body.push_back( new ExprStmt( noLabels, callAtexit ) );
594
595	// hoist variable and dtor caller decls to list of decls that will be added into global scope
596	staticDtorDecls.push_back( objDecl );
597	staticDtorDecls.push_back( dtorCaller );
598
599	// need to rename object uniquely since it now appears
600	// at global scope and there could be multiple function-scoped
601	// static variables with the same name in different functions.
602	// Note: it isn't sufficient to modify only the mangleName, because
603	// then subsequent Indexer passes can choke on seeing the object's name
604	// if another object has the same name and type. An unfortunate side-effect
605	// of renaming the object is that subsequent NameExprs may fail to resolve,
606	// but there shouldn't be any remaining past this point.
607	static UniqueName staticNamer( "_static_var" );
608	objDecl->set_name( objDecl->get_name() + staticNamer.newName() );
609	objDecl->set_mangleName( SymTab::Mangler::mangle( objDecl ) );
610
611	objDecl->set_init( NULL );
612	ctorInit->set_ctor( NULL );
613	delete ctorInit;
614
615	// xxx - temporary hack: need to return a declaration, but want to hoist the current object out of this scope
616	// create a new object which is never used
617	static UniqueName dummyNamer( "_dummy" );
618	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") } );
619	return dummy;
620	}
621	} else {
622	stmtsToAddAfter.push_back( ctor );
623	} // if
624	objDecl->set_init( NULL );
625	ctorInit->set_ctor( NULL );
626	} else if ( Initializer * init = ctorInit->get_init() ) {
627	objDecl->set_init( init );
628	ctorInit->set_init( NULL );
629	} else {
630	// no constructor and no initializer, which is okay
631	objDecl->set_init( NULL );
632	} // if
633	delete ctorInit;
634	} // if
635	return objDecl;
636	}
637
638	void ObjDeclCollector::visit( CompoundStmt *compoundStmt ) {
639	std::set< ObjectDecl * > prevVars = curVars;
640	Parent::visit( compoundStmt );
641	curVars = prevVars;
642	}
643
644	void ObjDeclCollector::visit( DeclStmt *stmt ) {
645	// keep track of all variables currently in scope
646	if ( ObjectDecl * objDecl = dynamic_cast< ObjectDecl * > ( stmt->get_decl() ) ) {
647	curVars.insert( objDecl );
648	} // if
649	Parent::visit( stmt );
650	}
651
652	void LabelFinder::handleStmt( Statement * stmt ) {
653	// for each label, remember the variables in scope at that label.
654	for ( Label l : stmt->get_labels() ) {
655	vars[l] = curVars;
656	} // for
657	}
658
659	template<typename Iterator, typename OutputIterator>
660	void insertDtors( Iterator begin, Iterator end, OutputIterator out ) {
661	for ( Iterator it = begin ; it != end ; ++it ) {
662	// extract destructor statement from the object decl and insert it into the output. Note that this is
663	// only called on lists of non-static objects with implicit non-intrinsic dtors, so if the user manually
664	// calls an intrinsic dtor then the call must (and will) still be generated since the argument may
665	// contain side effects.
666	ObjectDecl * objDecl = *it;
667	ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() );
668	assert( ctorInit && ctorInit->get_dtor() );
669	*out++ = ctorInit->get_dtor()->clone();
670	} // for
671	}
672
673	void InsertDtors::visit( ObjectDecl * objDecl ) {
674	// remember non-static destructed objects so that their destructors can be inserted later
675	if ( objDecl->get_storageClass() != DeclarationNode::Static ) {
676	if ( ConstructorInit * ctorInit = dynamic_cast< ConstructorInit * >( objDecl->get_init() ) ) {
677	// a decision should have been made by the resolver, so ctor and init are not both non-NULL
678	assert( ! ctorInit->get_ctor() \|\| ! ctorInit->get_init() );
679	Statement * dtor = ctorInit->get_dtor();
680	if ( dtor && ! isIntrinsicSingleArgCallStmt( dtor ) ) {
681	// don't need to call intrinsic dtor, because it does nothing, but
682	// non-intrinsic dtors must be called
683	reverseDeclOrder.front().push_front( objDecl );
684	} // if
685	} // if
686	} // if
687	Parent::visit( objDecl );
688	}
689
690	void InsertDtors::visit( CompoundStmt * compoundStmt ) {
691	// visit statements - this will also populate reverseDeclOrder list. don't want to dump all destructors
692	// when block is left, just the destructors associated with variables defined in this block, so push a new
693	// list to the top of the stack so that we can differentiate scopes
694	reverseDeclOrder.push_front( OrderedDecls() );
695	Parent::visit( compoundStmt );
696
697	// add destructors for the current scope that we're exiting
698	std::list< Statement * > & statements = compoundStmt->get_kids();
699	insertDtors( reverseDeclOrder.front().begin(), reverseDeclOrder.front().end(), back_inserter( statements ) );
700	reverseDeclOrder.pop_front();
701	}
702
703	void InsertDtors::visit( ReturnStmt * returnStmt ) {
704	// return exits all scopes, so dump destructors for all scopes
705	for ( OrderedDecls & od : reverseDeclOrder ) {
706	insertDtors( od.begin(), od.end(), back_inserter( stmtsToAdd ) );
707	} // for
708	}
709
710	// Handle break/continue/goto in the same manner as C++. Basic idea: any objects that are in scope at the
711	// BranchStmt but not at the labelled (target) statement must be destructed. If there are any objects in scope
712	// at the target location but not at the BranchStmt then those objects would be uninitialized so notify the user
713	// of the error. See C++ Reference 6.6 Jump Statements for details.
714	void InsertDtors::handleGoto( BranchStmt * stmt ) {
715	assert( stmt->get_target() != "" && "BranchStmt missing a label" );
716	// S_L = lvars = set of objects in scope at label definition
717	// S_G = curVars = set of objects in scope at goto statement
718	ObjectSet & lvars = labelVars[ stmt->get_target() ];
719
720	DTOR_PRINT(
721	std::cerr << "at goto label: " << stmt->get_target().get_name() << std::endl;
722	std::cerr << "S_G = " << printSet( curVars ) << std::endl;
723	std::cerr << "S_L = " << printSet( lvars ) << std::endl;
724	)
725
726	ObjectSet diff;
727	// S_L-S_G results in set of objects whose construction is skipped - it's an error if this set is non-empty
728	std::set_difference( lvars.begin(), lvars.end(), curVars.begin(), curVars.end(), std::inserter( diff, diff.begin() ) );
729	DTOR_PRINT(
730	std::cerr << "S_L-S_G = " << printSet( diff ) << std::endl;
731	)
732	if ( ! diff.empty() ) {
733	throw SemanticError( std::string("jump to label '") + stmt->get_target().get_name() + "' crosses initialization of " + (*diff.begin())->get_name() + " ", stmt );
734	} // if
735	// S_G-S_L results in set of objects that must be destructed
736	diff.clear();
737	std::set_difference( curVars.begin(), curVars.end(), lvars.begin(), lvars.end(), std::inserter( diff, diff.end() ) );
738	DTOR_PRINT(
739	std::cerr << "S_G-S_L = " << printSet( diff ) << std::endl;
740	)
741	if ( ! diff.empty() ) {
742	// go through decl ordered list of objectdecl. for each element that occurs in diff, output destructor
743	OrderedDecls ordered;
744	for ( OrderedDecls & rdo : reverseDeclOrder ) {
745	// add elements from reverseDeclOrder into ordered if they occur in diff - it is key that this happens in reverse declaration order.
746	copy_if( rdo.begin(), rdo.end(), back_inserter( ordered ), [&]( ObjectDecl * objDecl ) { return diff.count( objDecl ); } );
747	} // for
748	insertDtors( ordered.begin(), ordered.end(), back_inserter( stmtsToAdd ) );
749	} // if
750	}
751
752	void InsertDtors::visit( BranchStmt * stmt ) {
753	switch( stmt->get_type() ) {
754	case BranchStmt::Continue:
755	case BranchStmt::Break:
756	// could optimize the break/continue case, because the S_L-S_G check is unnecessary (this set should
757	// always be empty), but it serves as a small sanity check.
758	case BranchStmt::Goto:
759	handleGoto( stmt );
760	break;
761	default:
762	assert( false );
763	} // switch
764	}
765
766	bool checkWarnings( FunctionDecl * funcDecl ) {
767	// only check for warnings if the current function is a user-defined
768	// constructor or destructor
769	if ( ! funcDecl ) return false;
770	if ( ! funcDecl->get_statements() ) return false;
771	return isCtorDtor( funcDecl->get_name() ) && ! LinkageSpec::isOverridable( funcDecl->get_linkage() );
772	}
773
774	void GenStructMemberCalls::visit( FunctionDecl * funcDecl ) {
775	ValueGuard< FunctionDecl * > oldFunction( funcDecl );
776	ValueGuard< std::set< DeclarationWithType * > > oldUnhandled( unhandled );
777	ValueGuard< std::set< DeclarationWithType * > > oldUsedUninit( usedUninit );
778	ValueGuard< ObjectDecl * > oldThisParam( thisParam );
779	ValueGuard< bool > oldIsCtor( isCtor );
780	ValueGuard< StructDecl * > oldStructDecl( structDecl );
781
782	// need to start with fresh sets
783	unhandled.clear();
784	usedUninit.clear();
785
786	function = funcDecl;
787	isCtor = isConstructor( function->get_name() );
788	if ( checkWarnings( function ) ) {
789	FunctionType * type = function->get_functionType();
790	assert( ! type->get_parameters().empty() );
791	thisParam = safe_dynamic_cast< ObjectDecl * >( type->get_parameters().front() );
792	PointerType * ptrType = safe_dynamic_cast< PointerType * > ( thisParam->get_type() );
793	StructInstType * structType = dynamic_cast< StructInstType * >( ptrType->get_base() );
794	if ( structType ) {
795	structDecl = structType->get_baseStruct();
796	for ( Declaration * member : structDecl->get_members() ) {
797	if ( ObjectDecl * field = dynamic_cast< ObjectDecl * >( member ) ) {
798	// record all of the struct type's members that need to be constructed or
799	// destructed by the end of the function
800	unhandled.insert( field );
801	}
802	}
803	}
804	}
805	Parent::visit( function );
806
807	// remove the unhandled objects from usedUninit, because a call is inserted
808	// to handle them - only objects that are later constructed are used uninitialized.
809	std::set< DeclarationWithType * > diff;
810	std::set_difference( usedUninit.begin(), usedUninit.end(), unhandled.begin(), unhandled.end(), std::inserter( diff, diff.begin() ) );
811	for ( DeclarationWithType * member : diff ) {
812	emit( "in ", CodeGen::genType( function->get_functionType(), function->get_name(), false ), ", field ", member->get_name(), " used before being constructed" );
813	}
814
815	if ( ! unhandled.empty() ) {
816	// need to explicitly re-add function parameters in order to resolve copy constructors
817	enterScope();
818	maybeAccept( function->get_functionType(), *this );
819
820	// need to iterate through members in reverse in order for
821	// ctor/dtor statements to come out in the right order
822	for ( Declaration * member : reverseIterate( structDecl->get_members() ) ) {
823	DeclarationWithType * field = dynamic_cast< DeclarationWithType * >( member );
824	// skip non-DWT members
825	if ( ! field ) continue;
826	// skip handled members
827	if ( ! unhandled.count( field ) ) continue;
828
829	// insert and resolve default/copy constructor call for each field that's unhandled
830	std::list< Statement * > stmt;
831	UntypedExpr * deref = new UntypedExpr( new NameExpr( "*?" ) );
832	deref->get_args().push_back( new VariableExpr( thisParam ) );
833
834	Expression * arg2 = 0;
835	if ( isCopyConstructor( function ) ) {
836	// if copy ctor, need to pass second-param-of-this-function.field
837	std::list< DeclarationWithType * > & params = function->get_functionType()->get_parameters();
838	assert( params.size() == 2 );
839	arg2 = new MemberExpr( field, new VariableExpr( params.back() ) );
840	}
841	InitExpander srcParam( arg2 );
842	SymTab::genImplicitCall( srcParam, new MemberExpr( field, deref ), function->get_name(), back_inserter( stmt ), field, isCtor );
843
844	assert( stmt.size() <= 1 );
845	if ( stmt.size() == 1 ) {
846	Statement * callStmt = stmt.front();
847
848	MutatingResolver resolver( *this );
849	try {
850	callStmt->acceptMutator( resolver );
851	if ( isCtor ) {
852	function->get_statements()->push_front( callStmt );
853	} else {
854	// destructor statements should be added at the end
855	function->get_statements()->push_back( callStmt );
856	}
857	} catch ( SemanticError & error ) {
858	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" );
859	}
860	}
861	}
862	leaveScope();
863	}
864	}
865
866	void GenStructMemberCalls::visit( ApplicationExpr * appExpr ) {
867	if ( ! checkWarnings( function ) ) return;
868
869	std::string fname = getFunctionName( appExpr );
870	if ( fname == function->get_name() ) {
871	// call to same kind of function
872	Expression * firstParam = appExpr->get_args().front();
873
874	if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( firstParam ) ) {
875	// if calling another constructor on thisParam, assume that function handles
876	// all members - if it doesn't a warning will appear in that function.
877	if ( varExpr->get_var() == thisParam ) {
878	unhandled.clear();
879	}
880	} else {
881	// if first parameter is a member expression then
882	// remove the member from unhandled set.
883	handleFirstParam( firstParam );
884	}
885	}
886
887	Parent::visit( appExpr );
888	}
889
890	void GenStructMemberCalls::handleFirstParam( Expression * firstParam ) {
891	using namespace std;
892	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( firstParam ) ) {
893	if ( MemberExpr * memberExpr = dynamic_cast< MemberExpr * >( addrExpr->get_arg() ) ) {
894	if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
895	if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
896	if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
897	if ( varExpr->get_var() == thisParam ) {
898	unhandled.erase( memberExpr->get_member() );
899	}
900	}
901	}
902	}
903	}
904	}
905	}
906
907	void GenStructMemberCalls::visit( MemberExpr * memberExpr ) {
908	if ( ! checkWarnings( function ) ) return;
909	if ( ! isCtor ) return;
910
911	if ( ApplicationExpr * deref = dynamic_cast< ApplicationExpr * >( memberExpr->get_aggregate() ) ) {
912	if ( getFunctionName( deref ) == "*?" && deref->get_args().size() == 1 ) {
913	if ( VariableExpr * varExpr = dynamic_cast< VariableExpr * >( deref->get_args().front() ) ) {
914	if ( varExpr->get_var() == thisParam ) {
915	if ( unhandled.count( memberExpr->get_member() ) ) {
916	// emit a warning because a member was used before it was constructed
917	usedUninit.insert( memberExpr->get_member() );
918	}
919	}
920	}
921	}
922	}
923	Parent::visit( memberExpr );
924	}
925
926	template< typename Visitor, typename... Params >
927	void error( Visitor & v, const Params &... params ) {
928	v.errors.append( toString( params... ) );
929	}
930
931	template< typename... Params >
932	void GenStructMemberCalls::emit( const Params &... params ) {
933	// toggle warnings vs. errors here.
934	// warn( params... );
935	error( *this, params... );
936	}
937
938	DeclarationWithType * MutatingResolver::mutate( ObjectDecl *objectDecl ) {
939	// add object to the indexer assumes that there will be no name collisions
940	// in generated code. If this changes, add mutate methods for entities with
941	// scope and call {enter,leave}Scope explicitly.
942	objectDecl->accept( indexer );
943	return objectDecl;
944	}
945
946	Expression* MutatingResolver::mutate( UntypedExpr *untypedExpr ) {
947	return safe_dynamic_cast< ApplicationExpr * >( ResolvExpr::findVoidExpression( untypedExpr, indexer ) );
948	}
949
950	Expression * FixCtorExprs::mutate( ConstructorExpr * ctorExpr ) {
951	static UniqueName tempNamer( "_tmp_ctor_expr" );
952	assert( ctorExpr->get_results().size() == 1 );
953	ObjectDecl * tmp = new ObjectDecl( tempNamer.newName(), DeclarationNode::NoStorageClass, LinkageSpec::C, nullptr, ctorExpr->get_results().front()->clone(), nullptr );
954	addDeclaration( tmp );
955
956	ApplicationExpr * callExpr = safe_dynamic_cast< ApplicationExpr * > ( ctorExpr->get_callExpr() );
957	TypeSubstitution * env = ctorExpr->get_env();
958	ctorExpr->set_callExpr( nullptr );
959	ctorExpr->set_env( nullptr );
960
961	Expression *& firstArg = callExpr->get_args().front();
962	UntypedExpr * assign = new UntypedExpr( new NameExpr( "?=?" ) );
963	assign->get_args().push_back( new VariableExpr( tmp ) );
964	assign->get_args().push_back( firstArg );
965	cloneAll( ctorExpr->get_results(), assign->get_results() );
966	firstArg = assign;
967
968	CommaExpr * commaExpr = new CommaExpr( callExpr, new VariableExpr( tmp ) );
969	commaExpr->set_env( env );
970	delete ctorExpr;
971	return commaExpr;
972	}
973	} // namespace
974	} // namespace InitTweak
975
976	// Local Variables: //
977	// tab-width: 4 //
978	// mode: c++ //
979	// compile-command: "make install" //
980	// End: //

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