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source: src/ResolvExpr/TypeEnvironment.cc @ d22bf87

Last change on this file since d22bf87 was cd6a6ff, checked in by Thierry Delisle <tdelisle@…>, 4 years ago
Improved coverage of deterministic_output to be much finer grain.
Property mode set to `100644`
File size: 16.4 KB

Line
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	// TypeEnvironment.cc --
8	//
9	// Author : Richard C. Bilson
10	// Created On : Sun May 17 12:19:47 2015
11	// Last Modified By : Andrew Beach
12	// Last Modified On : Fri Jun 18 14:27:00 2019
13	// Update Count : 5
14	//
15
16	#include <cassert> // for assert
17	#include <algorithm> // for copy, set_intersection
18	#include <iterator> // for ostream_iterator, insert_iterator
19	#include <memory> // for unique_ptr
20	#include <utility> // for pair, move
21
22	#include "CompilationState.h" // for deterministic_output
23	#include "Common/utility.h" // for maybeClone
24	#include "SynTree/Type.h" // for Type, FunctionType, Type::Fora...
25	#include "SynTree/TypeSubstitution.h" // for TypeSubstitution
26	#include "Tuples/Tuples.h" // for isTtype
27	#include "TypeEnvironment.h"
28	#include "typeops.h" // for occurs
29	#include "Unify.h" // for unifyInexact
30
31	namespace ResolvExpr {
32	void printAssertionSet( const AssertionSet &assertions, std::ostream &os, int indent ) {
33	for ( AssertionSet::const_iterator i = assertions.begin(); i != assertions.end(); ++i ) {
34	i->first->print( os, indent );
35	if ( i->second.isUsed ) {
36	os << "(used)";
37	} else {
38	os << "(not used)";
39	} // if
40	} // for
41	}
42
43	void printOpenVarSet( const OpenVarSet &openVars, std::ostream &os, int indent ) {
44	os << std::string( indent, ' ' );
45	for ( OpenVarSet::const_iterator i = openVars.begin(); i != openVars.end(); ++i ) {
46	os << i->first << "(" << i->second << ") ";
47	} // for
48	}
49
50	void EqvClass::initialize( const EqvClass &src, EqvClass &dest ) {
51	initialize( src, dest, src.type );
52	}
53
54	void EqvClass::initialize( const EqvClass &src, EqvClass &dest, const Type *ty ) {
55	dest.vars = src.vars;
56	dest.type = maybeClone( ty );
57	dest.allowWidening = src.allowWidening;
58	dest.data = src.data;
59	}
60
61	EqvClass::EqvClass() : type( nullptr ), allowWidening( true ) {
62	}
63
64	EqvClass::EqvClass( const EqvClass &other ) {
65	initialize( other, *this );
66	}
67
68	EqvClass::EqvClass( const EqvClass &other, const Type *ty ) {
69	initialize( other, *this, ty );
70	}
71
72	EqvClass::EqvClass( EqvClass &&other )
73	: vars{std::move(other.vars)}, type{other.type},
74	allowWidening{std::move(other.allowWidening)}, data{std::move(other.data)} {
75	other.type = nullptr;
76	}
77
78	EqvClass &EqvClass::operator=( const EqvClass &other ) {
79	if ( this == &other ) return *this;
80	delete type;
81	initialize( other, *this );
82	return *this;
83	}
84
85	EqvClass &EqvClass::operator=( EqvClass &&other ) {
86	if ( this == &other ) return *this;
87	delete type;
88
89	vars = std::move(other.vars);
90	type = other.type;
91	other.type = nullptr;
92	allowWidening = std::move(other.allowWidening);
93	data = std::move(other.data);
94
95	return *this;
96	}
97
98	EqvClass::~EqvClass() {
99	delete type;
100	}
101
102	void EqvClass::set_type( Type* ty ) {
103	if ( ty == type ) return;
104	delete type;
105	type = ty;
106	}
107
108	void EqvClass::print( std::ostream &os, Indenter indent ) const {
109	os << "(";
110	bool first = true;
111	for(const auto & var : vars) {
112	if(first) first = false;
113	else os << " ";
114	if( deterministic_output && isUnboundType(var) ) os << "[unbound]";
115	else os << var;
116	}
117	os << ")";
118	if ( type ) {
119	os << " -> ";
120	type->print( os, indent+1 );
121	} // if
122	if ( ! allowWidening ) {
123	os << " (no widening)";
124	} // if
125	os << std::endl;
126	}
127
128	const EqvClass* TypeEnvironment::lookup( const std::string &var ) const {
129	for ( ClassList::const_iterator i = env.begin(); i != env.end(); ++i ) {
130	if ( i->vars.find( var ) != i->vars.end() ) return &*i;
131	} // for
132	return nullptr;
133	}
134
135	/// Removes any class from env that intersects eqvClass
136	void filterOverlappingClasses( std::list<EqvClass> &env, const EqvClass &eqvClass ) {
137	for ( auto i = env.begin(); i != env.end(); ) {
138	auto next = i;
139	++next;
140	std::set<std::string> intersection;
141	std::set_intersection( i->vars.begin(), i->vars.end(), eqvClass.vars.begin(), eqvClass.vars.end(),
142	std::inserter( intersection, intersection.begin() ) );
143	if ( ! intersection.empty() ) { env.erase( i ); }
144	i = next;
145	}
146	}
147
148	void TypeEnvironment::add( EqvClass &&eqvClass ) {
149	filterOverlappingClasses( env, eqvClass );
150	env.push_back( std::move(eqvClass) );
151	}
152
153	void TypeEnvironment::add( const Type::ForallList &tyDecls ) {
154	for ( Type::ForallList::const_iterator i = tyDecls.begin(); i != tyDecls.end(); ++i ) {
155	EqvClass newClass;
156	newClass.vars.insert( (*i)->get_name() );
157	newClass.data = TypeDecl::Data{ (*i) };
158	env.push_back( std::move(newClass) );
159	} // for
160	}
161
162	void TypeEnvironment::add( const TypeSubstitution & sub ) {
163	EqvClass newClass;
164	for ( auto p : sub ) {
165	newClass.vars.insert( p.first );
166	newClass.type = p.second->clone();
167	newClass.allowWidening = false;
168	// Minimal assumptions. Not technically correct, but might be good enough, and
169	// is the best we can do at the moment since information is lost in the
170	// transition to TypeSubstitution
171	newClass.data = TypeDecl::Data{ TypeDecl::Dtype, false };
172	add( std::move(newClass) );
173	}
174	}
175
176	void TypeEnvironment::makeSubstitution( TypeSubstitution &sub ) const {
177	for ( ClassList::const_iterator theClass = env.begin(); theClass != env.end(); ++theClass ) {
178	for ( std::set< std::string >::const_iterator theVar = theClass->vars.begin(); theVar != theClass->vars.end(); ++theVar ) {
179	if ( theClass->type ) {
180	sub.add( *theVar, theClass->type );
181	} else if ( theVar != theClass->vars.begin() ) {
182	TypeInstType newTypeInst = new TypeInstType( Type::Qualifiers(), theClass->vars.begin(), theClass->data.kind == TypeDecl::Ftype );
183	sub.add( *theVar, newTypeInst );
184	delete newTypeInst;
185	} // if
186	} // for
187	} // for
188	sub.normalize();
189	}
190
191	void TypeEnvironment::print( std::ostream &os, Indenter indent ) const {
192	for ( const EqvClass & theClass : env ) {
193	theClass.print( os, indent );
194	} // for
195	}
196
197	TypeEnvironment::ClassList::iterator TypeEnvironment::internal_lookup( const std::string &var ) {
198	for ( ClassList::iterator i = env.begin(); i != env.end(); ++i ) {
199	if ( i->vars.count( var ) ) return i;
200	} // for
201	return env.end();
202	}
203
204	void TypeEnvironment::simpleCombine( const TypeEnvironment &second ) {
205	env.insert( env.end(), second.env.begin(), second.env.end() );
206	}
207
208	// xxx -- this should maybe be worrying about iterator invalidation (see resolv-proto)
209	bool TypeEnvironment::mergeBound( EqvClass& to, const EqvClass& from, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
210	if ( from.type ) {
211	if ( to.type ) {
212	// attempt to unify bound types
213	std::unique_ptr<Type> toType{ to.type->clone() }, fromType{ from.type->clone() };
214	WidenMode widen{ to.allowWidening, from.allowWidening };
215	Type* common = nullptr;
216	AssertionSet need, have;
217	if ( unifyInexact( toType.get(), fromType.get(), *this, need, have, openVars, widen, indexer, common ) ) {
218	// unifies, set common type if necessary
219	if ( common ) {
220	common->get_qualifiers() = Type::Qualifiers{};
221	to.set_type( common );
222	}
223	} else return false; // cannot unify
224	} else {
225	to.type = from.type->clone();
226	}
227	}
228
229	// unify widening if matches
230	to.allowWidening &= from.allowWidening;
231	return true;
232	}
233
234	// xxx -- this should maybe be worrying about iterator invalidation (see resolv-proto)
235	bool TypeEnvironment::mergeClasses( TypeEnvironment::ClassList::iterator to, TypeEnvironment::ClassList::iterator from, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
236	EqvClass& r = *to;
237	EqvClass& s = *from;
238
239	// ensure bounds match
240	if ( ! mergeBound( r, s, openVars, indexer ) ) return false;
241
242	// check safely bindable
243	if ( r.type && occursIn( r.type, s.vars.begin(), s.vars.end(), *this ) ) return false;
244
245	// merge classes in
246	r.vars.insert( s.vars.begin(), s.vars.end() );
247	r.allowWidening &= s.allowWidening;
248	env.erase( from );
249
250	return true;
251	}
252
253	bool TypeEnvironment::combine( const TypeEnvironment& o, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
254	// short-circuit easy cases
255	if ( o.isEmpty() ) return true;
256	if ( isEmpty() ) {
257	simpleCombine( o );
258	return true;
259	}
260
261	// merge classes
262	for ( auto ct = o.env.begin(); ct != o.env.end(); ++ct ) {
263	const EqvClass& c = *ct;
264
265	// typeclass in local environment bound to c
266	auto rt = env.end();
267
268	// look for first existing bound variable
269	auto vt = c.vars.begin();
270	for ( ; vt != c.vars.end(); ++vt ) {
271	rt = internal_lookup( *vt );
272	if ( rt != env.end() ) break;
273	}
274
275	if ( rt != env.end() ) { // c needs to be merged into *rt
276	EqvClass& r = *rt;
277	// merge bindings
278	if ( ! mergeBound( r, c, openVars, indexer ) ) return false;
279	// merge previous unbound variables into this class, checking occurs if needed
280	if ( r.type ) for ( auto ut = c.vars.begin(); ut != vt; ++ut ) {
281	if ( occurs( r.type, ut, this ) ) return false;
282	r.vars.insert( *ut );
283	} else { r.vars.insert( c.vars.begin(), vt ); }
284	// merge subsequent variables into this class (skipping *vt, already there)
285	while ( ++vt != c.vars.end() ) {
286	auto st = internal_lookup( *vt );
287	if ( st == env.end() ) {
288	// unbound, safe to add if passes occurs
289	if ( r.type && occurs( r.type, vt, this ) ) return false;
290	r.vars.insert( *vt );
291	} else if ( st != rt ) {
292	// bound, but not to the same class
293	if ( ! mergeClasses( rt, st, openVars, indexer ) ) return false;
294	} // ignore bound into the same class
295	}
296	} else { // no variables in c bound; just copy up
297	env.push_back( c );
298	}
299	}
300
301	// merged all classes
302	return true;
303	}
304
305	void TypeEnvironment::extractOpenVars( OpenVarSet &openVars ) const {
306	for ( ClassList::const_iterator eqvClass = env.begin(); eqvClass != env.end(); ++eqvClass ) {
307	for ( std::set< std::string >::const_iterator var = eqvClass->vars.begin(); var != eqvClass->vars.end(); ++var ) {
308	openVars[ *var ] = eqvClass->data;
309	} // for
310	} // for
311	}
312
313	void TypeEnvironment::addActual( const TypeEnvironment& actualEnv, OpenVarSet& openVars ) {
314	for ( const EqvClass& c : actualEnv ) {
315	EqvClass c2 = c;
316	c2.allowWidening = false;
317	for ( const std::string& var : c2.vars ) {
318	openVars[ var ] = c2.data;
319	}
320	env.push_back( std::move(c2) );
321	}
322	}
323
324	bool isFtype( const Type * type ) {
325	if ( dynamic_cast< const FunctionType * >( type ) ) {
326	return true;
327	} else if ( const TypeInstType typeInst = dynamic_cast< const TypeInstType >( type ) ) {
328	return typeInst->get_isFtype();
329	} // if
330	return false;
331	}
332
333	bool tyVarCompatible( const TypeDecl::Data & data, const Type * type ) {
334	switch ( data.kind ) {
335	case TypeDecl::Dtype:
336	// to bind to an object type variable, the type must not be a function type.
337	// if the type variable is specified to be a complete type then the incoming
338	// type must also be complete
339	// xxx - should this also check that type is not a tuple type and that it's not a ttype?
340	return ! isFtype( type ) && (! data.isComplete \|\| type->isComplete() );
341	case TypeDecl::Ftype:
342	return isFtype( type );
343	case TypeDecl::Ttype:
344	// ttype unifies with any tuple type
345	return dynamic_cast< const TupleType * >( type ) \|\| Tuples::isTtype( type );
346	default:
347	assertf(false, "Unhandled tyvar kind: %d", data.kind);
348	} // switch
349	return false;
350	}
351
352	bool TypeEnvironment::bindVar( const TypeInstType typeInst, Type bindTo, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widen, const SymTab::Indexer &indexer ) {
353
354	// remove references from other, so that type variables can only bind to value types
355	bindTo = bindTo->stripReferences();
356	OpenVarSet::const_iterator tyvar = openVars.find( typeInst->get_name() );
357	assert( tyvar != openVars.end() );
358	if ( ! tyVarCompatible( tyvar->second, bindTo ) ) {
359	return false;
360	} // if
361	if ( occurs( bindTo, typeInst->get_name(), *this ) ) {
362	return false;
363	} // if
364	auto curClass = internal_lookup( typeInst->get_name() );
365	if ( curClass != env.end() ) {
366	if ( curClass->type ) {
367	Type *common = 0;
368	// attempt to unify equivalence class type (which has qualifiers stripped, so they must be restored) with the type to bind to
369	std::unique_ptr< Type > newType( curClass->type->clone() );
370	newType->tq = typeInst->tq;
371	if ( unifyInexact( newType.get(), bindTo, *this, need, have, openVars, widen & WidenMode( curClass->allowWidening, true ), indexer, common ) ) {
372	if ( common ) {
373	common->get_qualifiers() = Type::Qualifiers{};
374	curClass->set_type( common );
375	} // if
376	} else return false;
377	} else {
378	Type* newType = bindTo->clone();
379	newType->get_qualifiers() = Type::Qualifiers{};
380	curClass->set_type( newType );
381	curClass->allowWidening = widen.first && widen.second;
382	} // if
383	} else {
384	EqvClass newClass;
385	newClass.vars.insert( typeInst->get_name() );
386	newClass.type = bindTo->clone();
387	newClass.type->get_qualifiers() = Type::Qualifiers();
388	newClass.allowWidening = widen.first && widen.second;
389	newClass.data = data;
390	env.push_back( std::move(newClass) );
391	} // if
392	return true;
393	}
394
395	bool TypeEnvironment::bindVarToVar( const TypeInstType * var1, const TypeInstType * var2,
396	TypeDecl::Data && data, AssertionSet &need, AssertionSet &have,
397	const OpenVarSet &openVars, WidenMode widen, const SymTab::Indexer &indexer ) {
398
399	auto class1 = internal_lookup( var1->get_name() );
400	auto class2 = internal_lookup( var2->get_name() );
401
402	// exit early if variables already bound together
403	if ( class1 != env.end() && class1 == class2 ) {
404	class1->allowWidening &= widen;
405	return true;
406	}
407
408	bool widen1 = false, widen2 = false;
409	const Type type1 = nullptr, type2 = nullptr;
410
411	// check for existing bindings, perform occurs check
412	if ( class1 != env.end() ) {
413	if ( class1->type ) {
414	if ( occurs( class1->type, var2->get_name(), *this ) ) return false;
415	type1 = class1->type;
416	} // if
417	widen1 = widen.first && class1->allowWidening;
418	} // if
419	if ( class2 != env.end() ) {
420	if ( class2->type ) {
421	if ( occurs( class2->type, var1->get_name(), *this ) ) return false;
422	type2 = class2->type;
423	} // if
424	widen2 = widen.second && class2->allowWidening;
425	} // if
426
427	if ( type1 && type2 ) {
428	// both classes bound, merge if bound types can be unified
429	std::unique_ptr<Type> newType1{ type1->clone() }, newType2{ type2->clone() };
430	WidenMode newWidenMode{ widen1, widen2 };
431	Type *common = 0;
432	if ( unifyInexact( newType1.get(), newType2.get(), *this, need, have, openVars, newWidenMode, indexer, common ) ) {
433	class1->vars.insert( class2->vars.begin(), class2->vars.end() );
434	class1->allowWidening = widen1 && widen2;
435	if ( common ) {
436	common->get_qualifiers() = Type::Qualifiers{};
437	class1->set_type( common );
438	}
439	class1->data.isComplete \|= data.isComplete;
440	env.erase( class2 );
441	} else return false;
442	} else if ( class1 != env.end() && class2 != env.end() ) {
443	// both classes exist, at least one unbound, merge unconditionally
444	if ( type1 ) {
445	class1->vars.insert( class2->vars.begin(), class2->vars.end() );
446	class1->allowWidening = widen1;
447	class1->data.isComplete \|= data.isComplete;
448	env.erase( class2 );
449	} else {
450	class2->vars.insert( class1->vars.begin(), class1->vars.end() );
451	class2->allowWidening = widen2;
452	class2->data.isComplete \|= data.isComplete;
453	env.erase( class1 );
454	} // if
455	} else if ( class1 != env.end() ) {
456	// var2 unbound, add to class1
457	class1->vars.insert( var2->get_name() );
458	class1->allowWidening = widen1;
459	class1->data.isComplete \|= data.isComplete;
460	} else if ( class2 != env.end() ) {
461	// var1 unbound, add to class2
462	class2->vars.insert( var1->get_name() );
463	class2->allowWidening = widen2;
464	class2->data.isComplete \|= data.isComplete;
465	} else {
466	// neither var bound, create new class
467	EqvClass newClass;
468	newClass.vars.insert( var1->get_name() );
469	newClass.vars.insert( var2->get_name() );
470	newClass.allowWidening = widen1 && widen2;
471	newClass.data = data;
472	env.push_back( std::move(newClass) );
473	} // if
474	return true;
475	}
476
477	void TypeEnvironment::forbidWidening() {
478	for ( EqvClass& c : env ) c.allowWidening = false;
479	}
480
481	std::ostream & operator<<( std::ostream & out, const TypeEnvironment & env ) {
482	env.print( out );
483	return out;
484	}
485	} // namespace ResolvExpr
486
487	// Local Variables: //
488	// tab-width: 4 //
489	// mode: c++ //
490	// compile-command: "make install" //
491	// End: //

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