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source: src/ResolvExpr/AlternativeFinder.cc @ 8cc9e18

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

Last change on this file since 8cc9e18 was a1d7679, checked in by Aaron Moss <a3moss@…>, 8 years ago
Need a 4th level of recursive assertions to pass tests
Property mode set to `100644`
File size: 42.1 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	// AlternativeFinder.cc --
8	//
9	// Author : Richard C. Bilson
10	// Created On : Sat May 16 23:52:08 2015
11	// Last Modified By : Peter A. Buhr
12	// Last Modified On : Mon Jun 13 16:13:54 2016
13	// Update Count : 25
14	//
15
16	#include <list>
17	#include <iterator>
18	#include <algorithm>
19	#include <functional>
20	#include <cassert>
21	#include <unordered_map>
22	#include <utility>
23	#include <vector>
24
25	#include "AlternativeFinder.h"
26	#include "Alternative.h"
27	#include "Cost.h"
28	#include "typeops.h"
29	#include "Unify.h"
30	#include "RenameVars.h"
31	#include "SynTree/Type.h"
32	#include "SynTree/Declaration.h"
33	#include "SynTree/Expression.h"
34	#include "SynTree/Initializer.h"
35	#include "SynTree/Visitor.h"
36	#include "SymTab/Indexer.h"
37	#include "SymTab/Mangler.h"
38	#include "SynTree/TypeSubstitution.h"
39	#include "SymTab/Validate.h"
40	#include "Designators/Processor.h"
41	#include "Tuples/TupleAssignment.h"
42	#include "Tuples/NameMatcher.h"
43	#include "Common/utility.h"
44	#include "InitTweak/InitTweak.h"
45
46	extern bool resolvep;
47	#define PRINT( text ) if ( resolvep ) { text }
48	//#define DEBUG_COST
49
50	namespace ResolvExpr {
51	Expression resolveInVoidContext( Expression expr, const SymTab::Indexer &indexer, TypeEnvironment &env ) {
52	CastExpr *castToVoid = new CastExpr( expr );
53
54	AlternativeFinder finder( indexer, env );
55	finder.findWithAdjustment( castToVoid );
56
57	// it's a property of the language that a cast expression has either 1 or 0 interpretations; if it has 0
58	// interpretations, an exception has already been thrown.
59	assert( finder.get_alternatives().size() == 1 );
60	CastExpr newExpr = dynamic_cast< CastExpr >( finder.get_alternatives().front().expr );
61	assert( newExpr );
62	env = finder.get_alternatives().front().env;
63	return newExpr->get_arg()->clone();
64	}
65
66	namespace {
67	void printAlts( const AltList &list, std::ostream &os, int indent = 0 ) {
68	for ( AltList::const_iterator i = list.begin(); i != list.end(); ++i ) {
69	i->print( os, indent );
70	os << std::endl;
71	}
72	}
73
74	void makeExprList( const AltList &in, std::list< Expression* > &out ) {
75	for ( AltList::const_iterator i = in.begin(); i != in.end(); ++i ) {
76	out.push_back( i->expr->clone() );
77	}
78	}
79
80	Cost sumCost( const AltList &in ) {
81	Cost total;
82	for ( AltList::const_iterator i = in.begin(); i != in.end(); ++i ) {
83	total += i->cost;
84	}
85	return total;
86	}
87
88	struct PruneStruct {
89	bool isAmbiguous;
90	AltList::iterator candidate;
91	PruneStruct() {}
92	PruneStruct( AltList::iterator candidate ): isAmbiguous( false ), candidate( candidate ) {}
93	};
94
95	/// Prunes a list of alternatives down to those that have the minimum conversion cost for a given return type; skips ambiguous interpretations
96	template< typename InputIterator, typename OutputIterator >
97	void pruneAlternatives( InputIterator begin, InputIterator end, OutputIterator out, const SymTab::Indexer &indexer ) {
98	// select the alternatives that have the minimum conversion cost for a particular set of result types
99	std::map< std::string, PruneStruct > selected;
100	for ( AltList::iterator candidate = begin; candidate != end; ++candidate ) {
101	PruneStruct current( candidate );
102	std::string mangleName;
103	for ( std::list< Type* >::const_iterator retType = candidate->expr->get_results().begin(); retType != candidate->expr->get_results().end(); ++retType ) {
104	Type newType = (retType)->clone();
105	candidate->env.apply( newType );
106	mangleName += SymTab::Mangler::mangle( newType );
107	delete newType;
108	}
109	std::map< std::string, PruneStruct >::iterator mapPlace = selected.find( mangleName );
110	if ( mapPlace != selected.end() ) {
111	if ( candidate->cost < mapPlace->second.candidate->cost ) {
112	PRINT(
113	std::cerr << "cost " << candidate->cost << " beats " << mapPlace->second.candidate->cost << std::endl;
114	)
115	selected[ mangleName ] = current;
116	} else if ( candidate->cost == mapPlace->second.candidate->cost ) {
117	PRINT(
118	std::cerr << "marking ambiguous" << std::endl;
119	)
120	mapPlace->second.isAmbiguous = true;
121	}
122	} else {
123	selected[ mangleName ] = current;
124	}
125	}
126
127	PRINT(
128	std::cerr << "there are " << selected.size() << " alternatives before elimination" << std::endl;
129	)
130
131	// accept the alternatives that were unambiguous
132	for ( std::map< std::string, PruneStruct >::iterator target = selected.begin(); target != selected.end(); ++target ) {
133	if ( ! target->second.isAmbiguous ) {
134	Alternative &alt = *target->second.candidate;
135	for ( std::list< Type* >::iterator result = alt.expr->get_results().begin(); result != alt.expr->get_results().end(); ++result ) {
136	alt.env.applyFree( *result );
137	}
138	*out++ = alt;
139	}
140	}
141
142	}
143
144	template< typename InputIterator, typename OutputIterator >
145	void findMinCost( InputIterator begin, InputIterator end, OutputIterator out ) {
146	AltList alternatives;
147
148	// select the alternatives that have the minimum parameter cost
149	Cost minCost = Cost::infinity;
150	for ( AltList::iterator i = begin; i != end; ++i ) {
151	if ( i->cost < minCost ) {
152	minCost = i->cost;
153	i->cost = i->cvtCost;
154	alternatives.clear();
155	alternatives.push_back( *i );
156	} else if ( i->cost == minCost ) {
157	i->cost = i->cvtCost;
158	alternatives.push_back( *i );
159	}
160	}
161	std::copy( alternatives.begin(), alternatives.end(), out );
162	}
163
164	template< typename InputIterator >
165	void simpleCombineEnvironments( InputIterator begin, InputIterator end, TypeEnvironment &result ) {
166	while ( begin != end ) {
167	result.simpleCombine( (*begin++).env );
168	}
169	}
170
171	void renameTypes( Expression *expr ) {
172	for ( std::list< Type* >::iterator i = expr->get_results().begin(); i != expr->get_results().end(); ++i ) {
173	(*i)->accept( global_renamer );
174	}
175	}
176	}
177
178	template< typename InputIterator, typename OutputIterator >
179	void AlternativeFinder::findSubExprs( InputIterator begin, InputIterator end, OutputIterator out ) {
180	while ( begin != end ) {
181	AlternativeFinder finder( indexer, env );
182	finder.findWithAdjustment( *begin );
183	// XXX either this
184	//Designators::fixDesignations( finder, (*begin++)->get_argName() );
185	// or XXX this
186	begin++;
187	PRINT(
188	std::cerr << "findSubExprs" << std::endl;
189	printAlts( finder.alternatives, std::cerr );
190	)
191	*out++ = finder;
192	}
193	}
194
195	AlternativeFinder::AlternativeFinder( const SymTab::Indexer &indexer, const TypeEnvironment &env )
196	: indexer( indexer ), env( env ) {
197	}
198
199	void AlternativeFinder::find( Expression *expr, bool adjust ) {
200	expr->accept( *this );
201	if ( alternatives.empty() ) {
202	throw SemanticError( "No reasonable alternatives for expression ", expr );
203	}
204	for ( AltList::iterator i = alternatives.begin(); i != alternatives.end(); ++i ) {
205	if ( adjust ) {
206	adjustExprTypeList( i->expr->get_results().begin(), i->expr->get_results().end(), i->env, indexer );
207	}
208	}
209	PRINT(
210	std::cerr << "alternatives before prune:" << std::endl;
211	printAlts( alternatives, std::cerr );
212	)
213	AltList::iterator oldBegin = alternatives.begin();
214	pruneAlternatives( alternatives.begin(), alternatives.end(), front_inserter( alternatives ), indexer );
215	if ( alternatives.begin() == oldBegin ) {
216	std::ostringstream stream;
217	stream << "Can't choose between alternatives for expression ";
218	expr->print( stream );
219	stream << "Alternatives are:";
220	AltList winners;
221	findMinCost( alternatives.begin(), alternatives.end(), back_inserter( winners ) );
222	printAlts( winners, stream, 8 );
223	throw SemanticError( stream.str() );
224	}
225	alternatives.erase( oldBegin, alternatives.end() );
226	PRINT(
227	std::cerr << "there are " << alternatives.size() << " alternatives after elimination" << std::endl;
228	)
229	}
230
231	void AlternativeFinder::findWithAdjustment( Expression *expr ) {
232	find( expr, true );
233	}
234
235	template< typename StructOrUnionType >
236	void AlternativeFinder::addAggMembers( StructOrUnionType aggInst, Expression expr, const Cost &newCost, const std::string &name ) {
237	std::list< Declaration* > members;
238	aggInst->lookup( name, members );
239	for ( std::list< Declaration* >::const_iterator i = members.begin(); i != members.end(); ++i ) {
240	if ( DeclarationWithType dwt = dynamic_cast< DeclarationWithType >( *i ) ) {
241	alternatives.push_back( Alternative( new MemberExpr( dwt->clone(), expr->clone() ), env, newCost ) );
242	renameTypes( alternatives.back().expr );
243	} else {
244	assert( false );
245	}
246	}
247	}
248
249	void AlternativeFinder::visit( ApplicationExpr *applicationExpr ) {
250	alternatives.push_back( Alternative( applicationExpr->clone(), env, Cost::zero ) );
251	}
252
253	Cost computeConversionCost( Alternative &alt, const SymTab::Indexer &indexer ) {
254	ApplicationExpr appExpr = dynamic_cast< ApplicationExpr >( alt.expr );
255	assert( appExpr );
256	PointerType pointer = dynamic_cast< PointerType >( appExpr->get_function()->get_results().front() );
257	assert( pointer );
258	FunctionType function = dynamic_cast< FunctionType >( pointer->get_base() );
259	assert( function );
260
261	Cost convCost( 0, 0, 0 );
262	std::list< DeclarationWithType* >& formals = function->get_parameters();
263	std::list< DeclarationWithType* >::iterator formal = formals.begin();
264	std::list< Expression* >& actuals = appExpr->get_args();
265	for ( std::list< Expression* >::iterator actualExpr = actuals.begin(); actualExpr != actuals.end(); ++actualExpr ) {
266	PRINT(
267	std::cerr << "actual expression:" << std::endl;
268	(*actualExpr)->print( std::cerr, 8 );
269	std::cerr << "--- results are" << std::endl;
270	printAll( (*actualExpr)->get_results(), std::cerr, 8 );
271	)
272	std::list< DeclarationWithType* >::iterator startFormal = formal;
273	Cost actualCost;
274	for ( std::list< Type* >::iterator actual = (actualExpr)->get_results().begin(); actual != (actualExpr)->get_results().end(); ++actual ) {
275	if ( formal == formals.end() ) {
276	if ( function->get_isVarArgs() ) {
277	convCost += Cost( 1, 0, 0 );
278	break;
279	} else {
280	return Cost::infinity;
281	}
282	}
283	PRINT(
284	std::cerr << std::endl << "converting ";
285	(*actual)->print( std::cerr, 8 );
286	std::cerr << std::endl << " to ";
287	(*formal)->get_type()->print( std::cerr, 8 );
288	)
289	Cost newCost = conversionCost( actual, (formal)->get_type(), indexer, alt.env );
290	PRINT(
291	std::cerr << std::endl << "cost is" << newCost << std::endl;
292	)
293
294	if ( newCost == Cost::infinity ) {
295	return newCost;
296	}
297	convCost += newCost;
298	actualCost += newCost;
299
300	convCost += Cost( 0, polyCost( (formal)->get_type(), alt.env, indexer ) + polyCost( actual, alt.env, indexer ), 0 );
301
302	formal++;
303	}
304	if ( actualCost != Cost( 0, 0, 0 ) ) {
305	std::list< DeclarationWithType* >::iterator startFormalPlusOne = startFormal;
306	startFormalPlusOne++;
307	if ( formal == startFormalPlusOne ) {
308	// not a tuple type
309	Type newType = (startFormal)->get_type()->clone();
310	alt.env.apply( newType );
311	actualExpr = new CastExpr( actualExpr, newType );
312	} else {
313	TupleType *newType = new TupleType( Type::Qualifiers() );
314	for ( std::list< DeclarationWithType* >::iterator i = startFormal; i != formal; ++i ) {
315	newType->get_types().push_back( (*i)->get_type()->clone() );
316	}
317	alt.env.apply( newType );
318	actualExpr = new CastExpr( actualExpr, newType );
319	}
320	}
321
322	}
323	if ( formal != formals.end() ) {
324	return Cost::infinity;
325	}
326
327	for ( InferredParams::const_iterator assert = appExpr->get_inferParams().begin(); assert != appExpr->get_inferParams().end(); ++assert ) {
328	PRINT(
329	std::cerr << std::endl << "converting ";
330	assert->second.actualType->print( std::cerr, 8 );
331	std::cerr << std::endl << " to ";
332	assert->second.formalType->print( std::cerr, 8 );
333	)
334	Cost newCost = conversionCost( assert->second.actualType, assert->second.formalType, indexer, alt.env );
335	PRINT(
336	std::cerr << std::endl << "cost of conversion is " << newCost << std::endl;
337	)
338	if ( newCost == Cost::infinity ) {
339	return newCost;
340	}
341	convCost += newCost;
342
343	convCost += Cost( 0, polyCost( assert->second.formalType, alt.env, indexer ) + polyCost( assert->second.actualType, alt.env, indexer ), 0 );
344	}
345
346	return convCost;
347	}
348
349	/// Adds type variables to the open variable set and marks their assertions
350	void makeUnifiableVars( Type *type, OpenVarSet &unifiableVars, AssertionSet &needAssertions ) {
351	for ( std::list< TypeDecl* >::const_iterator tyvar = type->get_forall().begin(); tyvar != type->get_forall().end(); ++tyvar ) {
352	unifiableVars[ (tyvar)->get_name() ] = (tyvar)->get_kind();
353	for ( std::list< DeclarationWithType* >::iterator assert = (tyvar)->get_assertions().begin(); assert != (tyvar)->get_assertions().end(); ++assert ) {
354	needAssertions[ *assert ] = true;
355	}
356	/// needAssertions.insert( needAssertions.end(), (tyvar)->get_assertions().begin(), (tyvar)->get_assertions().end() );
357	}
358	}
359
360	bool AlternativeFinder::instantiateFunction( std::list< DeclarationWithType* >& formals, /const/ AltList &actuals, bool isVarArgs, OpenVarSet& openVars, TypeEnvironment &resultEnv, AssertionSet &resultNeed, AssertionSet &resultHave ) {
361	simpleCombineEnvironments( actuals.begin(), actuals.end(), resultEnv );
362	// make sure we don't widen any existing bindings
363	for ( TypeEnvironment::iterator i = resultEnv.begin(); i != resultEnv.end(); ++i ) {
364	i->allowWidening = false;
365	}
366	resultEnv.extractOpenVars( openVars );
367
368	/*
369	Tuples::NameMatcher matcher( formals );
370	try {
371	matcher.match( actuals );
372	} catch ( Tuples::NoMatch &e ) {
373	std::cerr << "Alternative doesn't match: " << e.message << std::endl;
374	}
375	*/
376	std::list< DeclarationWithType* >::iterator formal = formals.begin();
377	for ( AltList::const_iterator actualExpr = actuals.begin(); actualExpr != actuals.end(); ++actualExpr ) {
378	for ( std::list< Type* >::iterator actual = actualExpr->expr->get_results().begin(); actual != actualExpr->expr->get_results().end(); ++actual ) {
379	if ( formal == formals.end() ) {
380	return isVarArgs;
381	}
382	PRINT(
383	std::cerr << "formal type is ";
384	(*formal)->get_type()->print( std::cerr );
385	std::cerr << std::endl << "actual type is ";
386	(*actual)->print( std::cerr );
387	std::cerr << std::endl;
388	)
389	if ( ! unify( (formal)->get_type(), actual, resultEnv, resultNeed, resultHave, openVars, indexer ) ) {
390	return false;
391	}
392	formal++;
393	}
394	}
395	// Handling of default values
396	while ( formal != formals.end() ) {
397	if ( ObjectDecl od = dynamic_cast<ObjectDecl >( *formal ) )
398	if ( SingleInit si = dynamic_cast<SingleInit >( od->get_init() ))
399	// so far, only constant expressions are accepted as default values
400	if ( ConstantExpr cnstexpr = dynamic_cast<ConstantExpr >( si->get_value()) )
401	if ( Constant cnst = dynamic_cast<Constant >( cnstexpr->get_constant() ) )
402	if ( unify( (*formal)->get_type(), cnst->get_type(), resultEnv, resultNeed, resultHave, openVars, indexer ) ) {
403	// XXX Don't know if this is right
404	actuals.push_back( Alternative( cnstexpr->clone(), env, Cost::zero ) );
405	formal++;
406	if ( formal == formals.end()) break;
407	}
408	return false;
409	}
410	return true;
411	}
412
413	// /// Map of declaration uniqueIds (intended to be the assertions in an AssertionSet) to their parents and the number of times they've been included
414	//typedef std::unordered_map< UniqueId, std::unordered_map< UniqueId, unsigned > > AssertionParentSet;
415
416	static const int recursionLimit = /10/ 4; ///< Limit to depth of recursion satisfaction
417	//static const unsigned recursionParentLimit = 1; ///< Limit to the number of times an assertion can recursively use itself
418
419	void addToIndexer( AssertionSet &assertSet, SymTab::Indexer &indexer ) {
420	for ( AssertionSet::iterator i = assertSet.begin(); i != assertSet.end(); ++i ) {
421	if ( i->second == true ) {
422	i->first->accept( indexer );
423	}
424	}
425	}
426
427	template< typename ForwardIterator, typename OutputIterator >
428	void inferRecursive( ForwardIterator begin, ForwardIterator end, const Alternative &newAlt, OpenVarSet &openVars, const SymTab::Indexer &decls, const AssertionSet &newNeed, /const AssertionParentSet &needParents,/
429	int level, const SymTab::Indexer &indexer, OutputIterator out ) {
430	if ( begin == end ) {
431	if ( newNeed.empty() ) {
432	*out++ = newAlt;
433	return;
434	} else if ( level >= recursionLimit ) {
435	throw SemanticError( "Too many recursive assertions" );
436	} else {
437	AssertionSet newerNeed;
438	PRINT(
439	std::cerr << "recursing with new set:" << std::endl;
440	printAssertionSet( newNeed, std::cerr, 8 );
441	)
442	inferRecursive( newNeed.begin(), newNeed.end(), newAlt, openVars, decls, newerNeed, /needParents,/ level+1, indexer, out );
443	return;
444	}
445	}
446
447	ForwardIterator cur = begin++;
448	if ( ! cur->second ) {
449	inferRecursive( begin, end, newAlt, openVars, decls, newNeed, /needParents,/ level, indexer, out );
450	}
451	DeclarationWithType *curDecl = cur->first;
452	PRINT(
453	std::cerr << "inferRecursive: assertion is ";
454	curDecl->print( std::cerr );
455	std::cerr << std::endl;
456	)
457	std::list< DeclarationWithType* > candidates;
458	decls.lookupId( curDecl->get_name(), candidates );
459	/// if ( candidates.empty() ) { std::cerr << "no candidates!" << std::endl; }
460	for ( std::list< DeclarationWithType* >::const_iterator candidate = candidates.begin(); candidate != candidates.end(); ++candidate ) {
461	PRINT(
462	std::cerr << "inferRecursive: candidate is ";
463	(*candidate)->print( std::cerr );
464	std::cerr << std::endl;
465	)
466
467	AssertionSet newHave, newerNeed( newNeed );
468	TypeEnvironment newEnv( newAlt.env );
469	OpenVarSet newOpenVars( openVars );
470	Type adjType = (candidate)->get_type()->clone();
471	adjustExprType( adjType, newEnv, indexer );
472	adjType->accept( global_renamer );
473	PRINT(
474	std::cerr << "unifying ";
475	curDecl->get_type()->print( std::cerr );
476	std::cerr << " with ";
477	adjType->print( std::cerr );
478	std::cerr << std::endl;
479	)
480	if ( unify( curDecl->get_type(), adjType, newEnv, newerNeed, newHave, newOpenVars, indexer ) ) {
481	PRINT(
482	std::cerr << "success!" << std::endl;
483	)
484	SymTab::Indexer newDecls( decls );
485	addToIndexer( newHave, newDecls );
486	Alternative newerAlt( newAlt );
487	newerAlt.env = newEnv;
488	assert( (*candidate)->get_uniqueId() );
489	DeclarationWithType candDecl = static_cast< DeclarationWithType >( Declaration::declFromId( (*candidate)->get_uniqueId() ) );
490	//AssertionParentSet newNeedParents( needParents );
491	// skip repeatingly-self-recursive assertion satisfaction
492	// DOESN'T WORK: grandchild nodes conflict with their cousins
493	//if ( newNeedParents[ curDecl->get_uniqueId() ][ candDecl->get_uniqueId() ]++ > recursionParentLimit ) continue;
494	Expression *varExpr = new VariableExpr( candDecl );
495	deleteAll( varExpr->get_results() );
496	varExpr->get_results().clear();
497	varExpr->get_results().push_front( adjType->clone() );
498	PRINT(
499	std::cerr << "satisfying assertion " << curDecl->get_uniqueId() << " ";
500	curDecl->print( std::cerr );
501	std::cerr << " with declaration " << (*candidate)->get_uniqueId() << " ";
502	(*candidate)->print( std::cerr );
503	std::cerr << std::endl;
504	)
505	ApplicationExpr appExpr = static_cast< ApplicationExpr >( newerAlt.expr );
506	// XXX: this is a memory leak, but adjType can't be deleted because it might contain assertions
507	appExpr->get_inferParams()[ curDecl->get_uniqueId() ] = ParamEntry( (*candidate)->get_uniqueId(), adjType->clone(), curDecl->get_type()->clone(), varExpr );
508	inferRecursive( begin, end, newerAlt, newOpenVars, newDecls, newerNeed, /newNeedParents,/ level, indexer, out );
509	} else {
510	delete adjType;
511	}
512	}
513	}
514
515	template< typename OutputIterator >
516	void AlternativeFinder::inferParameters( const AssertionSet &need, AssertionSet &have, const Alternative &newAlt, OpenVarSet &openVars, OutputIterator out ) {
517	// PRINT(
518	// std::cerr << "inferParameters: assertions needed are" << std::endl;
519	// printAll( need, std::cerr, 8 );
520	// )
521	SymTab::Indexer decls( indexer );
522	PRINT(
523	std::cerr << "============= original indexer" << std::endl;
524	indexer.print( std::cerr );
525	std::cerr << "============= new indexer" << std::endl;
526	decls.print( std::cerr );
527	)
528	addToIndexer( have, decls );
529	AssertionSet newNeed;
530	//AssertionParentSet needParents;
531	inferRecursive( need.begin(), need.end(), newAlt, openVars, decls, newNeed, /needParents,/ 0, indexer, out );
532	// PRINT(
533	// std::cerr << "declaration 14 is ";
534	// Declaration::declFromId
535	// *out++ = newAlt;
536	// )
537	}
538
539	template< typename OutputIterator >
540	void AlternativeFinder::makeFunctionAlternatives( const Alternative &func, FunctionType *funcType, AltList &actualAlt, OutputIterator out ) {
541	OpenVarSet openVars;
542	AssertionSet resultNeed, resultHave;
543	TypeEnvironment resultEnv;
544	makeUnifiableVars( funcType, openVars, resultNeed );
545	if ( instantiateFunction( funcType->get_parameters(), actualAlt, funcType->get_isVarArgs(), openVars, resultEnv, resultNeed, resultHave ) ) {
546	ApplicationExpr *appExpr = new ApplicationExpr( func.expr->clone() );
547	Alternative newAlt( appExpr, resultEnv, sumCost( actualAlt ) );
548	makeExprList( actualAlt, appExpr->get_args() );
549	PRINT(
550	std::cerr << "need assertions:" << std::endl;
551	printAssertionSet( resultNeed, std::cerr, 8 );
552	)
553	inferParameters( resultNeed, resultHave, newAlt, openVars, out );
554	}
555	}
556
557	void AlternativeFinder::visit( UntypedExpr *untypedExpr ) {
558	bool doneInit = false;
559	AlternativeFinder funcOpFinder( indexer, env );
560
561	AlternativeFinder funcFinder( indexer, env );
562
563	{
564	std::string fname = InitTweak::getFunctionName( untypedExpr );
565	if ( fname == "&&" ) {
566	VoidType v = Type::Qualifiers(); // resolve to type void *
567	PointerType pt( Type::Qualifiers(), v.clone() );
568	UntypedExpr *vexpr = untypedExpr->clone();
569	vexpr->get_results().push_front( pt.clone() );
570	alternatives.push_back( Alternative( vexpr, env, Cost()) );
571	return;
572	}
573	}
574
575	funcFinder.findWithAdjustment( untypedExpr->get_function() );
576	std::list< AlternativeFinder > argAlternatives;
577	findSubExprs( untypedExpr->begin_args(), untypedExpr->end_args(), back_inserter( argAlternatives ) );
578
579	std::list< AltList > possibilities;
580	combos( argAlternatives.begin(), argAlternatives.end(), back_inserter( possibilities ) );
581
582	Tuples::TupleAssignSpotter tassign( this );
583	if ( tassign.isTupleAssignment( untypedExpr, possibilities ) ) {
584	// take care of possible tuple assignments, or discard expression
585	return;
586	} // else ...
587
588	AltList candidates;
589	SemanticError errors;
590
591	for ( AltList::const_iterator func = funcFinder.alternatives.begin(); func != funcFinder.alternatives.end(); ++func ) {
592	try {
593	PRINT(
594	std::cerr << "working on alternative: " << std::endl;
595	func->print( std::cerr, 8 );
596	)
597	// check if the type is pointer to function
598	PointerType *pointer;
599	if ( func->expr->get_results().size() == 1 && ( pointer = dynamic_cast< PointerType* >( func->expr->get_results().front() ) ) ) {
600	if ( FunctionType function = dynamic_cast< FunctionType >( pointer->get_base() ) ) {
601	for ( std::list< AltList >::iterator actualAlt = possibilities.begin(); actualAlt != possibilities.end(); ++actualAlt ) {
602	// XXX
603	//Designators::check_alternative( function, *actualAlt );
604	makeFunctionAlternatives( func, function, actualAlt, std::back_inserter( candidates ) );
605	}
606	} else if ( TypeInstType typeInst = dynamic_cast< TypeInstType >( pointer->get_base() ) ) {
607	EqvClass eqvClass;
608	if ( func->env.lookup( typeInst->get_name(), eqvClass ) && eqvClass.type ) {
609	if ( FunctionType function = dynamic_cast< FunctionType >( eqvClass.type ) ) {
610	for ( std::list< AltList >::iterator actualAlt = possibilities.begin(); actualAlt != possibilities.end(); ++actualAlt ) {
611	makeFunctionAlternatives( func, function, actualAlt, std::back_inserter( candidates ) );
612	} // for
613	} // if
614	} // if
615	} // if
616	} else {
617	// seek a function operator that's compatible
618	if ( ! doneInit ) {
619	doneInit = true;
620	NameExpr *opExpr = new NameExpr( "?()" );
621	try {
622	funcOpFinder.findWithAdjustment( opExpr );
623	} catch( SemanticError &e ) {
624	// it's ok if there aren't any defined function ops
625	}
626	PRINT(
627	std::cerr << "known function ops:" << std::endl;
628	printAlts( funcOpFinder.alternatives, std::cerr, 8 );
629	)
630	}
631
632	for ( AltList::const_iterator funcOp = funcOpFinder.alternatives.begin(); funcOp != funcOpFinder.alternatives.end(); ++funcOp ) {
633	// check if the type is pointer to function
634	PointerType *pointer;
635	if ( funcOp->expr->get_results().size() == 1
636	&& ( pointer = dynamic_cast< PointerType* >( funcOp->expr->get_results().front() ) ) ) {
637	if ( FunctionType function = dynamic_cast< FunctionType >( pointer->get_base() ) ) {
638	for ( std::list< AltList >::iterator actualAlt = possibilities.begin(); actualAlt != possibilities.end(); ++actualAlt ) {
639	AltList currentAlt;
640	currentAlt.push_back( *func );
641	currentAlt.insert( currentAlt.end(), actualAlt->begin(), actualAlt->end() );
642	makeFunctionAlternatives( *funcOp, function, currentAlt, std::back_inserter( candidates ) );
643	} // for
644	} // if
645	} // if
646	} // for
647	} // if
648	} catch ( SemanticError &e ) {
649	errors.append( e );
650	}
651	} // for
652
653	// Implement SFINAE; resolution errors are only errors if there aren't any non-erroneous resolutions
654	if ( candidates.empty() && ! errors.isEmpty() ) { throw errors; }
655
656	for ( AltList::iterator withFunc = candidates.begin(); withFunc != candidates.end(); ++withFunc ) {
657	Cost cvtCost = computeConversionCost( *withFunc, indexer );
658
659	PRINT(
660	ApplicationExpr appExpr = dynamic_cast< ApplicationExpr >( withFunc->expr );
661	assert( appExpr );
662	PointerType pointer = dynamic_cast< PointerType >( appExpr->get_function()->get_results().front() );
663	assert( pointer );
664	FunctionType function = dynamic_cast< FunctionType >( pointer->get_base() );
665	assert( function );
666	std::cerr << "Case +++++++++++++" << std::endl;
667	std::cerr << "formals are:" << std::endl;
668	printAll( function->get_parameters(), std::cerr, 8 );
669	std::cerr << "actuals are:" << std::endl;
670	printAll( appExpr->get_args(), std::cerr, 8 );
671	std::cerr << "bindings are:" << std::endl;
672	withFunc->env.print( std::cerr, 8 );
673	std::cerr << "cost of conversion is:" << cvtCost << std::endl;
674	)
675	if ( cvtCost != Cost::infinity ) {
676	withFunc->cvtCost = cvtCost;
677	alternatives.push_back( *withFunc );
678	} // if
679	} // for
680	candidates.clear();
681	candidates.splice( candidates.end(), alternatives );
682
683	findMinCost( candidates.begin(), candidates.end(), std::back_inserter( alternatives ) );
684	}
685
686	bool isLvalue( Expression *expr ) {
687	for ( std::list< Type* >::const_iterator i = expr->get_results().begin(); i != expr->get_results().end(); ++i ) {
688	if ( !(*i)->get_isLvalue() ) return false;
689	} // for
690	return true;
691	}
692
693	void AlternativeFinder::visit( AddressExpr *addressExpr ) {
694	AlternativeFinder finder( indexer, env );
695	finder.find( addressExpr->get_arg() );
696	for ( std::list< Alternative >::iterator i = finder.alternatives.begin(); i != finder.alternatives.end(); ++i ) {
697	if ( isLvalue( i->expr ) ) {
698	alternatives.push_back( Alternative( new AddressExpr( i->expr->clone() ), i->env, i->cost ) );
699	} // if
700	} // for
701	}
702
703	void AlternativeFinder::visit( CastExpr *castExpr ) {
704	for ( std::list< Type* >::iterator i = castExpr->get_results().begin(); i != castExpr->get_results().end(); ++i ) {
705	SymTab::validateType( *i, &indexer );
706	adjustExprType( *i, env, indexer );
707	} // for
708
709	AlternativeFinder finder( indexer, env );
710	finder.findWithAdjustment( castExpr->get_arg() );
711
712	AltList candidates;
713	for ( std::list< Alternative >::iterator i = finder.alternatives.begin(); i != finder.alternatives.end(); ++i ) {
714	AssertionSet needAssertions, haveAssertions;
715	OpenVarSet openVars;
716
717	// It's possible that a cast can throw away some values in a multiply-valued expression. (An example is a
718	// cast-to-void, which casts from one value to zero.) Figure out the prefix of the subexpression results
719	// that are cast directly. The candidate is invalid if it has fewer results than there are types to cast
720	// to.
721	int discardedValues = (*i).expr->get_results().size() - castExpr->get_results().size();
722	if ( discardedValues < 0 ) continue;
723	std::list< Type* >::iterator candidate_end = (*i).expr->get_results().begin();
724	std::advance( candidate_end, castExpr->get_results().size() );
725	// unification run for side-effects
726	unifyList( castExpr->get_results().begin(), castExpr->get_results().end(),
727	(*i).expr->get_results().begin(), candidate_end,
728	i->env, needAssertions, haveAssertions, openVars, indexer );
729	Cost thisCost = castCostList( (*i).expr->get_results().begin(), candidate_end,
730	castExpr->get_results().begin(), castExpr->get_results().end(),
731	indexer, i->env );
732	if ( thisCost != Cost::infinity ) {
733	// count one safe conversion for each value that is thrown away
734	thisCost += Cost( 0, 0, discardedValues );
735	CastExpr *newExpr = castExpr->clone();
736	newExpr->set_arg( i->expr->clone() );
737	candidates.push_back( Alternative( newExpr, i->env, i->cost, thisCost ) );
738	} // if
739	} // for
740
741	// findMinCost selects the alternatives with the lowest "cost" members, but has the side effect of copying the
742	// cvtCost member to the cost member (since the old cost is now irrelevant). Thus, calling findMinCost twice
743	// selects first based on argument cost, then on conversion cost.
744	AltList minArgCost;
745	findMinCost( candidates.begin(), candidates.end(), std::back_inserter( minArgCost ) );
746	findMinCost( minArgCost.begin(), minArgCost.end(), std::back_inserter( alternatives ) );
747	}
748
749	void AlternativeFinder::visit( UntypedMemberExpr *memberExpr ) {
750	AlternativeFinder funcFinder( indexer, env );
751	funcFinder.findWithAdjustment( memberExpr->get_aggregate() );
752
753	for ( AltList::const_iterator agg = funcFinder.alternatives.begin(); agg != funcFinder.alternatives.end(); ++agg ) {
754	if ( agg->expr->get_results().size() == 1 ) {
755	if ( StructInstType structInst = dynamic_cast< StructInstType >( agg->expr->get_results().front() ) ) {
756	addAggMembers( structInst, agg->expr, agg->cost, memberExpr->get_member() );
757	} else if ( UnionInstType unionInst = dynamic_cast< UnionInstType >( agg->expr->get_results().front() ) ) {
758	addAggMembers( unionInst, agg->expr, agg->cost, memberExpr->get_member() );
759	} // if
760	} // if
761	} // for
762	}
763
764	void AlternativeFinder::visit( MemberExpr *memberExpr ) {
765	alternatives.push_back( Alternative( memberExpr->clone(), env, Cost::zero ) );
766	}
767
768	void AlternativeFinder::visit( NameExpr *nameExpr ) {
769	std::list< DeclarationWithType* > declList;
770	indexer.lookupId( nameExpr->get_name(), declList );
771	PRINT( std::cerr << "nameExpr is " << nameExpr->get_name() << std::endl; )
772	for ( std::list< DeclarationWithType* >::iterator i = declList.begin(); i != declList.end(); ++i ) {
773	VariableExpr newExpr( *i, nameExpr->get_argName() );
774	newExpr.set_extension( nameExpr->get_extension() );
775	alternatives.push_back( Alternative( newExpr.clone(), env, Cost() ) );
776	PRINT(
777	std::cerr << "decl is ";
778	(*i)->print( std::cerr );
779	std::cerr << std::endl;
780	std::cerr << "newExpr is ";
781	newExpr.print( std::cerr );
782	std::cerr << std::endl;
783	)
784	renameTypes( alternatives.back().expr );
785	if ( StructInstType structInst = dynamic_cast< StructInstType >( (*i)->get_type() ) ) {
786	addAggMembers( structInst, &newExpr, Cost( 0, 0, 1 ), "" );
787	} else if ( UnionInstType unionInst = dynamic_cast< UnionInstType >( (*i)->get_type() ) ) {
788	addAggMembers( unionInst, &newExpr, Cost( 0, 0, 1 ), "" );
789	} // if
790	} // for
791	}
792
793	void AlternativeFinder::visit( VariableExpr *variableExpr ) {
794	alternatives.push_back( Alternative( variableExpr->clone(), env, Cost::zero ) );
795	}
796
797	void AlternativeFinder::visit( ConstantExpr *constantExpr ) {
798	alternatives.push_back( Alternative( constantExpr->clone(), env, Cost::zero ) );
799	}
800
801	void AlternativeFinder::visit( SizeofExpr *sizeofExpr ) {
802	if ( sizeofExpr->get_isType() ) {
803	alternatives.push_back( Alternative( sizeofExpr->clone(), env, Cost::zero ) );
804	} else {
805	// find all alternatives for the argument to sizeof
806	AlternativeFinder finder( indexer, env );
807	finder.find( sizeofExpr->get_expr() );
808	// find the lowest cost alternative among the alternatives, otherwise ambiguous
809	AltList winners;
810	findMinCost( finder.alternatives.begin(), finder.alternatives.end(), back_inserter( winners ) );
811	if ( winners.size() != 1 ) {
812	throw SemanticError( "Ambiguous expression in sizeof operand: ", sizeofExpr->get_expr() );
813	} // if
814	// return the lowest cost alternative for the argument
815	Alternative &choice = winners.front();
816	alternatives.push_back( Alternative( new SizeofExpr( choice.expr->clone() ), choice.env, Cost::zero ) );
817	} // if
818	}
819
820	void AlternativeFinder::visit( AlignofExpr *alignofExpr ) {
821	if ( alignofExpr->get_isType() ) {
822	alternatives.push_back( Alternative( alignofExpr->clone(), env, Cost::zero ) );
823	} else {
824	// find all alternatives for the argument to sizeof
825	AlternativeFinder finder( indexer, env );
826	finder.find( alignofExpr->get_expr() );
827	// find the lowest cost alternative among the alternatives, otherwise ambiguous
828	AltList winners;
829	findMinCost( finder.alternatives.begin(), finder.alternatives.end(), back_inserter( winners ) );
830	if ( winners.size() != 1 ) {
831	throw SemanticError( "Ambiguous expression in alignof operand: ", alignofExpr->get_expr() );
832	} // if
833	// return the lowest cost alternative for the argument
834	Alternative &choice = winners.front();
835	alternatives.push_back( Alternative( new AlignofExpr( choice.expr->clone() ), choice.env, Cost::zero ) );
836	} // if
837	}
838
839	template< typename StructOrUnionType >
840	void AlternativeFinder::addOffsetof( StructOrUnionType *aggInst, const std::string &name ) {
841	std::list< Declaration* > members;
842	aggInst->lookup( name, members );
843	for ( std::list< Declaration* >::const_iterator i = members.begin(); i != members.end(); ++i ) {
844	if ( DeclarationWithType dwt = dynamic_cast< DeclarationWithType >( *i ) ) {
845	alternatives.push_back( Alternative( new OffsetofExpr( aggInst->clone(), dwt->clone() ), env, Cost::zero ) );
846	renameTypes( alternatives.back().expr );
847	} else {
848	assert( false );
849	}
850	}
851	}
852
853	void AlternativeFinder::visit( UntypedOffsetofExpr *offsetofExpr ) {
854	AlternativeFinder funcFinder( indexer, env );
855	if ( StructInstType structInst = dynamic_cast< StructInstType >( offsetofExpr->get_type() ) ) {
856	addOffsetof( structInst, offsetofExpr->get_member() );
857	} else if ( UnionInstType unionInst = dynamic_cast< UnionInstType >( offsetofExpr->get_type() ) ) {
858	addOffsetof( unionInst, offsetofExpr->get_member() );
859	}
860	}
861
862	void AlternativeFinder::visit( OffsetofExpr *offsetofExpr ) {
863	alternatives.push_back( Alternative( offsetofExpr->clone(), env, Cost::zero ) );
864	}
865
866	void AlternativeFinder::visit( OffsetPackExpr *offsetPackExpr ) {
867	alternatives.push_back( Alternative( offsetPackExpr->clone(), env, Cost::zero ) );
868	}
869
870	void AlternativeFinder::resolveAttr( DeclarationWithType funcDecl, FunctionType function, Type *argType, const TypeEnvironment &env ) {
871	// assume no polymorphism
872	// assume no implicit conversions
873	assert( function->get_parameters().size() == 1 );
874	PRINT(
875	std::cerr << "resolvAttr: funcDecl is ";
876	funcDecl->print( std::cerr );
877	std::cerr << " argType is ";
878	argType->print( std::cerr );
879	std::cerr << std::endl;
880	)
881	if ( typesCompatibleIgnoreQualifiers( argType, function->get_parameters().front()->get_type(), indexer, env ) ) {
882	alternatives.push_back( Alternative( new AttrExpr( new VariableExpr( funcDecl ), argType->clone() ), env, Cost::zero ) );
883	for ( std::list< DeclarationWithType* >::iterator i = function->get_returnVals().begin(); i != function->get_returnVals().end(); ++i ) {
884	alternatives.back().expr->get_results().push_back( (*i)->get_type()->clone() );
885	} // for
886	} // if
887	}
888
889	void AlternativeFinder::visit( AttrExpr *attrExpr ) {
890	// assume no 'pointer-to-attribute'
891	NameExpr nameExpr = dynamic_cast< NameExpr >( attrExpr->get_attr() );
892	assert( nameExpr );
893	std::list< DeclarationWithType* > attrList;
894	indexer.lookupId( nameExpr->get_name(), attrList );
895	if ( attrExpr->get_isType() \|\| attrExpr->get_expr() ) {
896	for ( std::list< DeclarationWithType* >::iterator i = attrList.begin(); i != attrList.end(); ++i ) {
897	// check if the type is function
898	if ( FunctionType function = dynamic_cast< FunctionType >( (*i)->get_type() ) ) {
899	// assume exactly one parameter
900	if ( function->get_parameters().size() == 1 ) {
901	if ( attrExpr->get_isType() ) {
902	resolveAttr( *i, function, attrExpr->get_type(), env );
903	} else {
904	AlternativeFinder finder( indexer, env );
905	finder.find( attrExpr->get_expr() );
906	for ( AltList::iterator choice = finder.alternatives.begin(); choice != finder.alternatives.end(); ++choice ) {
907	if ( choice->expr->get_results().size() == 1 ) {
908	resolveAttr(*i, function, choice->expr->get_results().front(), choice->env );
909	} // fi
910	} // for
911	} // if
912	} // if
913	} // if
914	} // for
915	} else {
916	for ( std::list< DeclarationWithType* >::iterator i = attrList.begin(); i != attrList.end(); ++i ) {
917	VariableExpr newExpr( *i );
918	alternatives.push_back( Alternative( newExpr.clone(), env, Cost() ) );
919	renameTypes( alternatives.back().expr );
920	} // for
921	} // if
922	}
923
924	void AlternativeFinder::visit( LogicalExpr *logicalExpr ) {
925	AlternativeFinder firstFinder( indexer, env );
926	firstFinder.findWithAdjustment( logicalExpr->get_arg1() );
927	for ( AltList::const_iterator first = firstFinder.alternatives.begin(); first != firstFinder.alternatives.end(); ++first ) {
928	AlternativeFinder secondFinder( indexer, first->env );
929	secondFinder.findWithAdjustment( logicalExpr->get_arg2() );
930	for ( AltList::const_iterator second = secondFinder.alternatives.begin(); second != secondFinder.alternatives.end(); ++second ) {
931	LogicalExpr *newExpr = new LogicalExpr( first->expr->clone(), second->expr->clone(), logicalExpr->get_isAnd() );
932	alternatives.push_back( Alternative( newExpr, second->env, first->cost + second->cost ) );
933	}
934	}
935	}
936
937	void AlternativeFinder::visit( ConditionalExpr *conditionalExpr ) {
938	AlternativeFinder firstFinder( indexer, env );
939	firstFinder.findWithAdjustment( conditionalExpr->get_arg1() );
940	for ( AltList::const_iterator first = firstFinder.alternatives.begin(); first != firstFinder.alternatives.end(); ++first ) {
941	AlternativeFinder secondFinder( indexer, first->env );
942	secondFinder.findWithAdjustment( conditionalExpr->get_arg2() );
943	for ( AltList::const_iterator second = secondFinder.alternatives.begin(); second != secondFinder.alternatives.end(); ++second ) {
944	AlternativeFinder thirdFinder( indexer, second->env );
945	thirdFinder.findWithAdjustment( conditionalExpr->get_arg3() );
946	for ( AltList::const_iterator third = thirdFinder.alternatives.begin(); third != thirdFinder.alternatives.end(); ++third ) {
947	OpenVarSet openVars;
948	AssertionSet needAssertions, haveAssertions;
949	Alternative newAlt( 0, third->env, first->cost + second->cost + third->cost );
950	std::list< Type* > commonTypes;
951	if ( unifyList( second->expr->get_results().begin(), second->expr->get_results().end(), third->expr->get_results().begin(), third->expr->get_results().end(), newAlt.env, needAssertions, haveAssertions, openVars, indexer, commonTypes ) ) {
952	ConditionalExpr *newExpr = new ConditionalExpr( first->expr->clone(), second->expr->clone(), third->expr->clone() );
953	std::list< Type* >::const_iterator original = second->expr->get_results().begin();
954	std::list< Type* >::const_iterator commonType = commonTypes.begin();
955	for ( ; original != second->expr->get_results().end() && commonType != commonTypes.end(); ++original, ++commonType ) {
956	if ( *commonType ) {
957	newExpr->get_results().push_back( *commonType );
958	} else {
959	newExpr->get_results().push_back( (*original)->clone() );
960	} // if
961	} // for
962	newAlt.expr = newExpr;
963	inferParameters( needAssertions, haveAssertions, newAlt, openVars, back_inserter( alternatives ) );
964	} // if
965	} // for
966	} // for
967	} // for
968	}
969
970	void AlternativeFinder::visit( CommaExpr *commaExpr ) {
971	TypeEnvironment newEnv( env );
972	Expression *newFirstArg = resolveInVoidContext( commaExpr->get_arg1(), indexer, newEnv );
973	AlternativeFinder secondFinder( indexer, newEnv );
974	secondFinder.findWithAdjustment( commaExpr->get_arg2() );
975	for ( AltList::const_iterator alt = secondFinder.alternatives.begin(); alt != secondFinder.alternatives.end(); ++alt ) {
976	alternatives.push_back( Alternative( new CommaExpr( newFirstArg->clone(), alt->expr->clone() ), alt->env, alt->cost ) );
977	} // for
978	delete newFirstArg;
979	}
980
981	void AlternativeFinder::visit( TupleExpr *tupleExpr ) {
982	std::list< AlternativeFinder > subExprAlternatives;
983	findSubExprs( tupleExpr->get_exprs().begin(), tupleExpr->get_exprs().end(), back_inserter( subExprAlternatives ) );
984	std::list< AltList > possibilities;
985	combos( subExprAlternatives.begin(), subExprAlternatives.end(), back_inserter( possibilities ) );
986	for ( std::list< AltList >::const_iterator i = possibilities.begin(); i != possibilities.end(); ++i ) {
987	TupleExpr *newExpr = new TupleExpr;
988	makeExprList( *i, newExpr->get_exprs() );
989	for ( std::list< Expression* >::const_iterator resultExpr = newExpr->get_exprs().begin(); resultExpr != newExpr->get_exprs().end(); ++resultExpr ) {
990	for ( std::list< Type* >::const_iterator resultType = (resultExpr)->get_results().begin(); resultType != (resultExpr)->get_results().end(); ++resultType ) {
991	newExpr->get_results().push_back( (*resultType)->clone() );
992	} // for
993	} // for
994
995	TypeEnvironment compositeEnv;
996	simpleCombineEnvironments( i->begin(), i->end(), compositeEnv );
997	alternatives.push_back( Alternative( newExpr, compositeEnv, sumCost( *i ) ) );
998	} // for
999	}
1000
1001	void AlternativeFinder::visit( ImplicitCopyCtorExpr * impCpCtorExpr ) {
1002	alternatives.push_back( Alternative( impCpCtorExpr->clone(), env, Cost::zero ) );
1003	}
1004	} // namespace ResolvExpr
1005
1006	// Local Variables: //
1007	// tab-width: 4 //
1008	// mode: c++ //
1009	// compile-command: "make install" //
1010	// End: //

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