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source: src/ResolvExpr/AlternativeFinder.cc @ 87b5bf0

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

Last change on this file since 87b5bf0 was 22cad76, checked in by Aaron Moss <a3moss@…>, 8 years ago
Second attempt to break resolver loop
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	// 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; ///< 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	if ( newNeedParents[ curDecl->get_uniqueId() ][ candDecl->get_uniqueId() ]++ > recursionParentLimit ) continue;
493	Expression *varExpr = new VariableExpr( candDecl );
494	deleteAll( varExpr->get_results() );
495	varExpr->get_results().clear();
496	varExpr->get_results().push_front( adjType->clone() );
497	PRINT(
498	std::cerr << "satisfying assertion " << curDecl->get_uniqueId() << " ";
499	curDecl->print( std::cerr );
500	std::cerr << " with declaration " << (*candidate)->get_uniqueId() << " ";
501	(*candidate)->print( std::cerr );
502	std::cerr << std::endl;
503	)
504	ApplicationExpr appExpr = static_cast< ApplicationExpr >( newerAlt.expr );
505	// XXX: this is a memory leak, but adjType can't be deleted because it might contain assertions
506	appExpr->get_inferParams()[ curDecl->get_uniqueId() ] = ParamEntry( (*candidate)->get_uniqueId(), adjType->clone(), curDecl->get_type()->clone(), varExpr );
507	inferRecursive( begin, end, newerAlt, newOpenVars, newDecls, newerNeed, newNeedParents, level, indexer, out );
508	} else {
509	delete adjType;
510	}
511	}
512	}
513
514	template< typename OutputIterator >
515	void AlternativeFinder::inferParameters( const AssertionSet &need, AssertionSet &have, const Alternative &newAlt, OpenVarSet &openVars, OutputIterator out ) {
516	// PRINT(
517	// std::cerr << "inferParameters: assertions needed are" << std::endl;
518	// printAll( need, std::cerr, 8 );
519	// )
520	SymTab::Indexer decls( indexer );
521	PRINT(
522	std::cerr << "============= original indexer" << std::endl;
523	indexer.print( std::cerr );
524	std::cerr << "============= new indexer" << std::endl;
525	decls.print( std::cerr );
526	)
527	addToIndexer( have, decls );
528	AssertionSet newNeed;
529	AssertionParentSet needParents;
530	inferRecursive( need.begin(), need.end(), newAlt, openVars, decls, newNeed, needParents, 0, indexer, out );
531	// PRINT(
532	// std::cerr << "declaration 14 is ";
533	// Declaration::declFromId
534	// *out++ = newAlt;
535	// )
536	}
537
538	template< typename OutputIterator >
539	void AlternativeFinder::makeFunctionAlternatives( const Alternative &func, FunctionType *funcType, AltList &actualAlt, OutputIterator out ) {
540	OpenVarSet openVars;
541	AssertionSet resultNeed, resultHave;
542	TypeEnvironment resultEnv;
543	makeUnifiableVars( funcType, openVars, resultNeed );
544	if ( instantiateFunction( funcType->get_parameters(), actualAlt, funcType->get_isVarArgs(), openVars, resultEnv, resultNeed, resultHave ) ) {
545	ApplicationExpr *appExpr = new ApplicationExpr( func.expr->clone() );
546	Alternative newAlt( appExpr, resultEnv, sumCost( actualAlt ) );
547	makeExprList( actualAlt, appExpr->get_args() );
548	PRINT(
549	std::cerr << "need assertions:" << std::endl;
550	printAssertionSet( resultNeed, std::cerr, 8 );
551	)
552	inferParameters( resultNeed, resultHave, newAlt, openVars, out );
553	}
554	}
555
556	void AlternativeFinder::visit( UntypedExpr *untypedExpr ) {
557	bool doneInit = false;
558	AlternativeFinder funcOpFinder( indexer, env );
559
560	AlternativeFinder funcFinder( indexer, env );
561
562	{
563	std::string fname = InitTweak::getFunctionName( untypedExpr );
564	if ( fname == "&&" ) {
565	VoidType v = Type::Qualifiers(); // resolve to type void *
566	PointerType pt( Type::Qualifiers(), v.clone() );
567	UntypedExpr *vexpr = untypedExpr->clone();
568	vexpr->get_results().push_front( pt.clone() );
569	alternatives.push_back( Alternative( vexpr, env, Cost()) );
570	return;
571	}
572	}
573
574	funcFinder.findWithAdjustment( untypedExpr->get_function() );
575	std::list< AlternativeFinder > argAlternatives;
576	findSubExprs( untypedExpr->begin_args(), untypedExpr->end_args(), back_inserter( argAlternatives ) );
577
578	std::list< AltList > possibilities;
579	combos( argAlternatives.begin(), argAlternatives.end(), back_inserter( possibilities ) );
580
581	Tuples::TupleAssignSpotter tassign( this );
582	if ( tassign.isTupleAssignment( untypedExpr, possibilities ) ) {
583	// take care of possible tuple assignments, or discard expression
584	return;
585	} // else ...
586
587	AltList candidates;
588	SemanticError errors;
589
590	for ( AltList::const_iterator func = funcFinder.alternatives.begin(); func != funcFinder.alternatives.end(); ++func ) {
591	try {
592	PRINT(
593	std::cerr << "working on alternative: " << std::endl;
594	func->print( std::cerr, 8 );
595	)
596	// check if the type is pointer to function
597	PointerType *pointer;
598	if ( func->expr->get_results().size() == 1 && ( pointer = dynamic_cast< PointerType* >( func->expr->get_results().front() ) ) ) {
599	if ( FunctionType function = dynamic_cast< FunctionType >( pointer->get_base() ) ) {
600	for ( std::list< AltList >::iterator actualAlt = possibilities.begin(); actualAlt != possibilities.end(); ++actualAlt ) {
601	// XXX
602	//Designators::check_alternative( function, *actualAlt );
603	makeFunctionAlternatives( func, function, actualAlt, std::back_inserter( candidates ) );
604	}
605	} else if ( TypeInstType typeInst = dynamic_cast< TypeInstType >( pointer->get_base() ) ) {
606	EqvClass eqvClass;
607	if ( func->env.lookup( typeInst->get_name(), eqvClass ) && eqvClass.type ) {
608	if ( FunctionType function = dynamic_cast< FunctionType >( eqvClass.type ) ) {
609	for ( std::list< AltList >::iterator actualAlt = possibilities.begin(); actualAlt != possibilities.end(); ++actualAlt ) {
610	makeFunctionAlternatives( func, function, actualAlt, std::back_inserter( candidates ) );
611	} // for
612	} // if
613	} // if
614	} // if
615	} else {
616	// seek a function operator that's compatible
617	if ( ! doneInit ) {
618	doneInit = true;
619	NameExpr *opExpr = new NameExpr( "?()" );
620	try {
621	funcOpFinder.findWithAdjustment( opExpr );
622	} catch( SemanticError &e ) {
623	// it's ok if there aren't any defined function ops
624	}
625	PRINT(
626	std::cerr << "known function ops:" << std::endl;
627	printAlts( funcOpFinder.alternatives, std::cerr, 8 );
628	)
629	}
630
631	for ( AltList::const_iterator funcOp = funcOpFinder.alternatives.begin(); funcOp != funcOpFinder.alternatives.end(); ++funcOp ) {
632	// check if the type is pointer to function
633	PointerType *pointer;
634	if ( funcOp->expr->get_results().size() == 1
635	&& ( pointer = dynamic_cast< PointerType* >( funcOp->expr->get_results().front() ) ) ) {
636	if ( FunctionType function = dynamic_cast< FunctionType >( pointer->get_base() ) ) {
637	for ( std::list< AltList >::iterator actualAlt = possibilities.begin(); actualAlt != possibilities.end(); ++actualAlt ) {
638	AltList currentAlt;
639	currentAlt.push_back( *func );
640	currentAlt.insert( currentAlt.end(), actualAlt->begin(), actualAlt->end() );
641	makeFunctionAlternatives( *funcOp, function, currentAlt, std::back_inserter( candidates ) );
642	} // for
643	} // if
644	} // if
645	} // for
646	} // if
647	} catch ( SemanticError &e ) {
648	errors.append( e );
649	}
650	} // for
651
652	// Implement SFINAE; resolution errors are only errors if there aren't any non-erroneous resolutions
653	if ( candidates.empty() && ! errors.isEmpty() ) { throw errors; }
654
655	for ( AltList::iterator withFunc = candidates.begin(); withFunc != candidates.end(); ++withFunc ) {
656	Cost cvtCost = computeConversionCost( *withFunc, indexer );
657
658	PRINT(
659	ApplicationExpr appExpr = dynamic_cast< ApplicationExpr >( withFunc->expr );
660	assert( appExpr );
661	PointerType pointer = dynamic_cast< PointerType >( appExpr->get_function()->get_results().front() );
662	assert( pointer );
663	FunctionType function = dynamic_cast< FunctionType >( pointer->get_base() );
664	assert( function );
665	std::cerr << "Case +++++++++++++" << std::endl;
666	std::cerr << "formals are:" << std::endl;
667	printAll( function->get_parameters(), std::cerr, 8 );
668	std::cerr << "actuals are:" << std::endl;
669	printAll( appExpr->get_args(), std::cerr, 8 );
670	std::cerr << "bindings are:" << std::endl;
671	withFunc->env.print( std::cerr, 8 );
672	std::cerr << "cost of conversion is:" << cvtCost << std::endl;
673	)
674	if ( cvtCost != Cost::infinity ) {
675	withFunc->cvtCost = cvtCost;
676	alternatives.push_back( *withFunc );
677	} // if
678	} // for
679	candidates.clear();
680	candidates.splice( candidates.end(), alternatives );
681
682	findMinCost( candidates.begin(), candidates.end(), std::back_inserter( alternatives ) );
683	}
684
685	bool isLvalue( Expression *expr ) {
686	for ( std::list< Type* >::const_iterator i = expr->get_results().begin(); i != expr->get_results().end(); ++i ) {
687	if ( !(*i)->get_isLvalue() ) return false;
688	} // for
689	return true;
690	}
691
692	void AlternativeFinder::visit( AddressExpr *addressExpr ) {
693	AlternativeFinder finder( indexer, env );
694	finder.find( addressExpr->get_arg() );
695	for ( std::list< Alternative >::iterator i = finder.alternatives.begin(); i != finder.alternatives.end(); ++i ) {
696	if ( isLvalue( i->expr ) ) {
697	alternatives.push_back( Alternative( new AddressExpr( i->expr->clone() ), i->env, i->cost ) );
698	} // if
699	} // for
700	}
701
702	void AlternativeFinder::visit( CastExpr *castExpr ) {
703	for ( std::list< Type* >::iterator i = castExpr->get_results().begin(); i != castExpr->get_results().end(); ++i ) {
704	SymTab::validateType( *i, &indexer );
705	adjustExprType( *i, env, indexer );
706	} // for
707
708	AlternativeFinder finder( indexer, env );
709	finder.findWithAdjustment( castExpr->get_arg() );
710
711	AltList candidates;
712	for ( std::list< Alternative >::iterator i = finder.alternatives.begin(); i != finder.alternatives.end(); ++i ) {
713	AssertionSet needAssertions, haveAssertions;
714	OpenVarSet openVars;
715
716	// It's possible that a cast can throw away some values in a multiply-valued expression. (An example is a
717	// cast-to-void, which casts from one value to zero.) Figure out the prefix of the subexpression results
718	// that are cast directly. The candidate is invalid if it has fewer results than there are types to cast
719	// to.
720	int discardedValues = (*i).expr->get_results().size() - castExpr->get_results().size();
721	if ( discardedValues < 0 ) continue;
722	std::list< Type* >::iterator candidate_end = (*i).expr->get_results().begin();
723	std::advance( candidate_end, castExpr->get_results().size() );
724	// unification run for side-effects
725	unifyList( castExpr->get_results().begin(), castExpr->get_results().end(),
726	(*i).expr->get_results().begin(), candidate_end,
727	i->env, needAssertions, haveAssertions, openVars, indexer );
728	Cost thisCost = castCostList( (*i).expr->get_results().begin(), candidate_end,
729	castExpr->get_results().begin(), castExpr->get_results().end(),
730	indexer, i->env );
731	if ( thisCost != Cost::infinity ) {
732	// count one safe conversion for each value that is thrown away
733	thisCost += Cost( 0, 0, discardedValues );
734	CastExpr *newExpr = castExpr->clone();
735	newExpr->set_arg( i->expr->clone() );
736	candidates.push_back( Alternative( newExpr, i->env, i->cost, thisCost ) );
737	} // if
738	} // for
739
740	// findMinCost selects the alternatives with the lowest "cost" members, but has the side effect of copying the
741	// cvtCost member to the cost member (since the old cost is now irrelevant). Thus, calling findMinCost twice
742	// selects first based on argument cost, then on conversion cost.
743	AltList minArgCost;
744	findMinCost( candidates.begin(), candidates.end(), std::back_inserter( minArgCost ) );
745	findMinCost( minArgCost.begin(), minArgCost.end(), std::back_inserter( alternatives ) );
746	}
747
748	void AlternativeFinder::visit( UntypedMemberExpr *memberExpr ) {
749	AlternativeFinder funcFinder( indexer, env );
750	funcFinder.findWithAdjustment( memberExpr->get_aggregate() );
751
752	for ( AltList::const_iterator agg = funcFinder.alternatives.begin(); agg != funcFinder.alternatives.end(); ++agg ) {
753	if ( agg->expr->get_results().size() == 1 ) {
754	if ( StructInstType structInst = dynamic_cast< StructInstType >( agg->expr->get_results().front() ) ) {
755	addAggMembers( structInst, agg->expr, agg->cost, memberExpr->get_member() );
756	} else if ( UnionInstType unionInst = dynamic_cast< UnionInstType >( agg->expr->get_results().front() ) ) {
757	addAggMembers( unionInst, agg->expr, agg->cost, memberExpr->get_member() );
758	} // if
759	} // if
760	} // for
761	}
762
763	void AlternativeFinder::visit( MemberExpr *memberExpr ) {
764	alternatives.push_back( Alternative( memberExpr->clone(), env, Cost::zero ) );
765	}
766
767	void AlternativeFinder::visit( NameExpr *nameExpr ) {
768	std::list< DeclarationWithType* > declList;
769	indexer.lookupId( nameExpr->get_name(), declList );
770	PRINT( std::cerr << "nameExpr is " << nameExpr->get_name() << std::endl; )
771	for ( std::list< DeclarationWithType* >::iterator i = declList.begin(); i != declList.end(); ++i ) {
772	VariableExpr newExpr( *i, nameExpr->get_argName() );
773	newExpr.set_extension( nameExpr->get_extension() );
774	alternatives.push_back( Alternative( newExpr.clone(), env, Cost() ) );
775	PRINT(
776	std::cerr << "decl is ";
777	(*i)->print( std::cerr );
778	std::cerr << std::endl;
779	std::cerr << "newExpr is ";
780	newExpr.print( std::cerr );
781	std::cerr << std::endl;
782	)
783	renameTypes( alternatives.back().expr );
784	if ( StructInstType structInst = dynamic_cast< StructInstType >( (*i)->get_type() ) ) {
785	addAggMembers( structInst, &newExpr, Cost( 0, 0, 1 ), "" );
786	} else if ( UnionInstType unionInst = dynamic_cast< UnionInstType >( (*i)->get_type() ) ) {
787	addAggMembers( unionInst, &newExpr, Cost( 0, 0, 1 ), "" );
788	} // if
789	} // for
790	}
791
792	void AlternativeFinder::visit( VariableExpr *variableExpr ) {
793	alternatives.push_back( Alternative( variableExpr->clone(), env, Cost::zero ) );
794	}
795
796	void AlternativeFinder::visit( ConstantExpr *constantExpr ) {
797	alternatives.push_back( Alternative( constantExpr->clone(), env, Cost::zero ) );
798	}
799
800	void AlternativeFinder::visit( SizeofExpr *sizeofExpr ) {
801	if ( sizeofExpr->get_isType() ) {
802	alternatives.push_back( Alternative( sizeofExpr->clone(), env, Cost::zero ) );
803	} else {
804	// find all alternatives for the argument to sizeof
805	AlternativeFinder finder( indexer, env );
806	finder.find( sizeofExpr->get_expr() );
807	// find the lowest cost alternative among the alternatives, otherwise ambiguous
808	AltList winners;
809	findMinCost( finder.alternatives.begin(), finder.alternatives.end(), back_inserter( winners ) );
810	if ( winners.size() != 1 ) {
811	throw SemanticError( "Ambiguous expression in sizeof operand: ", sizeofExpr->get_expr() );
812	} // if
813	// return the lowest cost alternative for the argument
814	Alternative &choice = winners.front();
815	alternatives.push_back( Alternative( new SizeofExpr( choice.expr->clone() ), choice.env, Cost::zero ) );
816	} // if
817	}
818
819	void AlternativeFinder::visit( AlignofExpr *alignofExpr ) {
820	if ( alignofExpr->get_isType() ) {
821	alternatives.push_back( Alternative( alignofExpr->clone(), env, Cost::zero ) );
822	} else {
823	// find all alternatives for the argument to sizeof
824	AlternativeFinder finder( indexer, env );
825	finder.find( alignofExpr->get_expr() );
826	// find the lowest cost alternative among the alternatives, otherwise ambiguous
827	AltList winners;
828	findMinCost( finder.alternatives.begin(), finder.alternatives.end(), back_inserter( winners ) );
829	if ( winners.size() != 1 ) {
830	throw SemanticError( "Ambiguous expression in alignof operand: ", alignofExpr->get_expr() );
831	} // if
832	// return the lowest cost alternative for the argument
833	Alternative &choice = winners.front();
834	alternatives.push_back( Alternative( new AlignofExpr( choice.expr->clone() ), choice.env, Cost::zero ) );
835	} // if
836	}
837
838	template< typename StructOrUnionType >
839	void AlternativeFinder::addOffsetof( StructOrUnionType *aggInst, const std::string &name ) {
840	std::list< Declaration* > members;
841	aggInst->lookup( name, members );
842	for ( std::list< Declaration* >::const_iterator i = members.begin(); i != members.end(); ++i ) {
843	if ( DeclarationWithType dwt = dynamic_cast< DeclarationWithType >( *i ) ) {
844	alternatives.push_back( Alternative( new OffsetofExpr( aggInst->clone(), dwt->clone() ), env, Cost::zero ) );
845	renameTypes( alternatives.back().expr );
846	} else {
847	assert( false );
848	}
849	}
850	}
851
852	void AlternativeFinder::visit( UntypedOffsetofExpr *offsetofExpr ) {
853	AlternativeFinder funcFinder( indexer, env );
854	if ( StructInstType structInst = dynamic_cast< StructInstType >( offsetofExpr->get_type() ) ) {
855	addOffsetof( structInst, offsetofExpr->get_member() );
856	} else if ( UnionInstType unionInst = dynamic_cast< UnionInstType >( offsetofExpr->get_type() ) ) {
857	addOffsetof( unionInst, offsetofExpr->get_member() );
858	}
859	}
860
861	void AlternativeFinder::visit( OffsetofExpr *offsetofExpr ) {
862	alternatives.push_back( Alternative( offsetofExpr->clone(), env, Cost::zero ) );
863	}
864
865	void AlternativeFinder::visit( OffsetPackExpr *offsetPackExpr ) {
866	alternatives.push_back( Alternative( offsetPackExpr->clone(), env, Cost::zero ) );
867	}
868
869	void AlternativeFinder::resolveAttr( DeclarationWithType funcDecl, FunctionType function, Type *argType, const TypeEnvironment &env ) {
870	// assume no polymorphism
871	// assume no implicit conversions
872	assert( function->get_parameters().size() == 1 );
873	PRINT(
874	std::cerr << "resolvAttr: funcDecl is ";
875	funcDecl->print( std::cerr );
876	std::cerr << " argType is ";
877	argType->print( std::cerr );
878	std::cerr << std::endl;
879	)
880	if ( typesCompatibleIgnoreQualifiers( argType, function->get_parameters().front()->get_type(), indexer, env ) ) {
881	alternatives.push_back( Alternative( new AttrExpr( new VariableExpr( funcDecl ), argType->clone() ), env, Cost::zero ) );
882	for ( std::list< DeclarationWithType* >::iterator i = function->get_returnVals().begin(); i != function->get_returnVals().end(); ++i ) {
883	alternatives.back().expr->get_results().push_back( (*i)->get_type()->clone() );
884	} // for
885	} // if
886	}
887
888	void AlternativeFinder::visit( AttrExpr *attrExpr ) {
889	// assume no 'pointer-to-attribute'
890	NameExpr nameExpr = dynamic_cast< NameExpr >( attrExpr->get_attr() );
891	assert( nameExpr );
892	std::list< DeclarationWithType* > attrList;
893	indexer.lookupId( nameExpr->get_name(), attrList );
894	if ( attrExpr->get_isType() \|\| attrExpr->get_expr() ) {
895	for ( std::list< DeclarationWithType* >::iterator i = attrList.begin(); i != attrList.end(); ++i ) {
896	// check if the type is function
897	if ( FunctionType function = dynamic_cast< FunctionType >( (*i)->get_type() ) ) {
898	// assume exactly one parameter
899	if ( function->get_parameters().size() == 1 ) {
900	if ( attrExpr->get_isType() ) {
901	resolveAttr( *i, function, attrExpr->get_type(), env );
902	} else {
903	AlternativeFinder finder( indexer, env );
904	finder.find( attrExpr->get_expr() );
905	for ( AltList::iterator choice = finder.alternatives.begin(); choice != finder.alternatives.end(); ++choice ) {
906	if ( choice->expr->get_results().size() == 1 ) {
907	resolveAttr(*i, function, choice->expr->get_results().front(), choice->env );
908	} // fi
909	} // for
910	} // if
911	} // if
912	} // if
913	} // for
914	} else {
915	for ( std::list< DeclarationWithType* >::iterator i = attrList.begin(); i != attrList.end(); ++i ) {
916	VariableExpr newExpr( *i );
917	alternatives.push_back( Alternative( newExpr.clone(), env, Cost() ) );
918	renameTypes( alternatives.back().expr );
919	} // for
920	} // if
921	}
922
923	void AlternativeFinder::visit( LogicalExpr *logicalExpr ) {
924	AlternativeFinder firstFinder( indexer, env );
925	firstFinder.findWithAdjustment( logicalExpr->get_arg1() );
926	for ( AltList::const_iterator first = firstFinder.alternatives.begin(); first != firstFinder.alternatives.end(); ++first ) {
927	AlternativeFinder secondFinder( indexer, first->env );
928	secondFinder.findWithAdjustment( logicalExpr->get_arg2() );
929	for ( AltList::const_iterator second = secondFinder.alternatives.begin(); second != secondFinder.alternatives.end(); ++second ) {
930	LogicalExpr *newExpr = new LogicalExpr( first->expr->clone(), second->expr->clone(), logicalExpr->get_isAnd() );
931	alternatives.push_back( Alternative( newExpr, second->env, first->cost + second->cost ) );
932	}
933	}
934	}
935
936	void AlternativeFinder::visit( ConditionalExpr *conditionalExpr ) {
937	AlternativeFinder firstFinder( indexer, env );
938	firstFinder.findWithAdjustment( conditionalExpr->get_arg1() );
939	for ( AltList::const_iterator first = firstFinder.alternatives.begin(); first != firstFinder.alternatives.end(); ++first ) {
940	AlternativeFinder secondFinder( indexer, first->env );
941	secondFinder.findWithAdjustment( conditionalExpr->get_arg2() );
942	for ( AltList::const_iterator second = secondFinder.alternatives.begin(); second != secondFinder.alternatives.end(); ++second ) {
943	AlternativeFinder thirdFinder( indexer, second->env );
944	thirdFinder.findWithAdjustment( conditionalExpr->get_arg3() );
945	for ( AltList::const_iterator third = thirdFinder.alternatives.begin(); third != thirdFinder.alternatives.end(); ++third ) {
946	OpenVarSet openVars;
947	AssertionSet needAssertions, haveAssertions;
948	Alternative newAlt( 0, third->env, first->cost + second->cost + third->cost );
949	std::list< Type* > commonTypes;
950	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 ) ) {
951	ConditionalExpr *newExpr = new ConditionalExpr( first->expr->clone(), second->expr->clone(), third->expr->clone() );
952	std::list< Type* >::const_iterator original = second->expr->get_results().begin();
953	std::list< Type* >::const_iterator commonType = commonTypes.begin();
954	for ( ; original != second->expr->get_results().end() && commonType != commonTypes.end(); ++original, ++commonType ) {
955	if ( *commonType ) {
956	newExpr->get_results().push_back( *commonType );
957	} else {
958	newExpr->get_results().push_back( (*original)->clone() );
959	} // if
960	} // for
961	newAlt.expr = newExpr;
962	inferParameters( needAssertions, haveAssertions, newAlt, openVars, back_inserter( alternatives ) );
963	} // if
964	} // for
965	} // for
966	} // for
967	}
968
969	void AlternativeFinder::visit( CommaExpr *commaExpr ) {
970	TypeEnvironment newEnv( env );
971	Expression *newFirstArg = resolveInVoidContext( commaExpr->get_arg1(), indexer, newEnv );
972	AlternativeFinder secondFinder( indexer, newEnv );
973	secondFinder.findWithAdjustment( commaExpr->get_arg2() );
974	for ( AltList::const_iterator alt = secondFinder.alternatives.begin(); alt != secondFinder.alternatives.end(); ++alt ) {
975	alternatives.push_back( Alternative( new CommaExpr( newFirstArg->clone(), alt->expr->clone() ), alt->env, alt->cost ) );
976	} // for
977	delete newFirstArg;
978	}
979
980	void AlternativeFinder::visit( TupleExpr *tupleExpr ) {
981	std::list< AlternativeFinder > subExprAlternatives;
982	findSubExprs( tupleExpr->get_exprs().begin(), tupleExpr->get_exprs().end(), back_inserter( subExprAlternatives ) );
983	std::list< AltList > possibilities;
984	combos( subExprAlternatives.begin(), subExprAlternatives.end(), back_inserter( possibilities ) );
985	for ( std::list< AltList >::const_iterator i = possibilities.begin(); i != possibilities.end(); ++i ) {
986	TupleExpr *newExpr = new TupleExpr;
987	makeExprList( *i, newExpr->get_exprs() );
988	for ( std::list< Expression* >::const_iterator resultExpr = newExpr->get_exprs().begin(); resultExpr != newExpr->get_exprs().end(); ++resultExpr ) {
989	for ( std::list< Type* >::const_iterator resultType = (resultExpr)->get_results().begin(); resultType != (resultExpr)->get_results().end(); ++resultType ) {
990	newExpr->get_results().push_back( (*resultType)->clone() );
991	} // for
992	} // for
993
994	TypeEnvironment compositeEnv;
995	simpleCombineEnvironments( i->begin(), i->end(), compositeEnv );
996	alternatives.push_back( Alternative( newExpr, compositeEnv, sumCost( *i ) ) );
997	} // for
998	}
999
1000	void AlternativeFinder::visit( ImplicitCopyCtorExpr * impCpCtorExpr ) {
1001	alternatives.push_back( Alternative( impCpCtorExpr->clone(), env, Cost::zero ) );
1002	}
1003	} // namespace ResolvExpr
1004
1005	// Local Variables: //
1006	// tab-width: 4 //
1007	// mode: c++ //
1008	// compile-command: "make install" //
1009	// End: //

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