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source: src/ResolvExpr/TypeEnvironment.cc @ b5276fc

ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-astnew-ast-unique-exprpthread-emulationqualifiedEnum

Last change on this file since b5276fc was 7215000, checked in by Thierry Delisle <tdelisle@…>, 5 years ago
Added flag to disable non-deteministic parts of the output when testing
Property mode set to `100644`
File size: 16.4 KB

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1	//
2	// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3	//
4	// The contents of this file are covered under the licence agreement in the
5	// file "LICENCE" distributed with Cforall.
6	//
7	// 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	if( !deterministic_output ) {
110	os << "( ";
111	std::copy( vars.begin(), vars.end(), std::ostream_iterator< std::string >( os, " " ) );
112	os << ")";
113	}
114	if ( type ) {
115	os << " -> ";
116	type->print( os, indent+1 );
117	} // if
118	if ( ! allowWidening ) {
119	os << " (no widening)";
120	} // if
121	os << std::endl;
122	}
123
124	const EqvClass* TypeEnvironment::lookup( const std::string &var ) const {
125	for ( ClassList::const_iterator i = env.begin(); i != env.end(); ++i ) {
126	if ( i->vars.find( var ) != i->vars.end() ) return &*i;
127	} // for
128	return nullptr;
129	}
130
131	/// Removes any class from env that intersects eqvClass
132	void filterOverlappingClasses( std::list<EqvClass> &env, const EqvClass &eqvClass ) {
133	for ( auto i = env.begin(); i != env.end(); ) {
134	auto next = i;
135	++next;
136	std::set<std::string> intersection;
137	std::set_intersection( i->vars.begin(), i->vars.end(), eqvClass.vars.begin(), eqvClass.vars.end(),
138	std::inserter( intersection, intersection.begin() ) );
139	if ( ! intersection.empty() ) { env.erase( i ); }
140	i = next;
141	}
142	}
143
144	void TypeEnvironment::add( EqvClass &&eqvClass ) {
145	filterOverlappingClasses( env, eqvClass );
146	env.push_back( std::move(eqvClass) );
147	}
148
149	void TypeEnvironment::add( const Type::ForallList &tyDecls ) {
150	for ( Type::ForallList::const_iterator i = tyDecls.begin(); i != tyDecls.end(); ++i ) {
151	EqvClass newClass;
152	newClass.vars.insert( (*i)->get_name() );
153	newClass.data = TypeDecl::Data{ (*i) };
154	env.push_back( std::move(newClass) );
155	} // for
156	}
157
158	void TypeEnvironment::add( const TypeSubstitution & sub ) {
159	EqvClass newClass;
160	for ( auto p : sub ) {
161	newClass.vars.insert( p.first );
162	newClass.type = p.second->clone();
163	newClass.allowWidening = false;
164	// Minimal assumptions. Not technically correct, but might be good enough, and
165	// is the best we can do at the moment since information is lost in the
166	// transition to TypeSubstitution
167	newClass.data = TypeDecl::Data{ TypeDecl::Dtype, false };
168	add( std::move(newClass) );
169	}
170	}
171
172	void TypeEnvironment::makeSubstitution( TypeSubstitution &sub ) const {
173	for ( ClassList::const_iterator theClass = env.begin(); theClass != env.end(); ++theClass ) {
174	for ( std::set< std::string >::const_iterator theVar = theClass->vars.begin(); theVar != theClass->vars.end(); ++theVar ) {
175	if ( theClass->type ) {
176	sub.add( *theVar, theClass->type );
177	} else if ( theVar != theClass->vars.begin() ) {
178	TypeInstType newTypeInst = new TypeInstType( Type::Qualifiers(), theClass->vars.begin(), theClass->data.kind == TypeDecl::Ftype );
179	sub.add( *theVar, newTypeInst );
180	delete newTypeInst;
181	} // if
182	} // for
183	} // for
184	sub.normalize();
185	}
186
187	void TypeEnvironment::print( std::ostream &os, Indenter indent ) const {
188	for ( const EqvClass & theClass : env ) {
189	theClass.print( os, indent );
190	} // for
191	}
192
193	TypeEnvironment::ClassList::iterator TypeEnvironment::internal_lookup( const std::string &var ) {
194	for ( ClassList::iterator i = env.begin(); i != env.end(); ++i ) {
195	if ( i->vars.count( var ) ) return i;
196	} // for
197	return env.end();
198	}
199
200	void TypeEnvironment::simpleCombine( const TypeEnvironment &second ) {
201	env.insert( env.end(), second.env.begin(), second.env.end() );
202	}
203
204	// xxx -- this should maybe be worrying about iterator invalidation (see resolv-proto)
205	bool TypeEnvironment::mergeBound( EqvClass& to, const EqvClass& from, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
206	if ( from.type ) {
207	if ( to.type ) {
208	// attempt to unify bound types
209	std::unique_ptr<Type> toType{ to.type->clone() }, fromType{ from.type->clone() };
210	WidenMode widen{ to.allowWidening, from.allowWidening };
211	Type* common = nullptr;
212	AssertionSet need, have;
213	if ( unifyInexact( toType.get(), fromType.get(), *this, need, have, openVars, widen, indexer, common ) ) {
214	// unifies, set common type if necessary
215	if ( common ) {
216	common->get_qualifiers() = Type::Qualifiers{};
217	to.set_type( common );
218	}
219	} else return false; // cannot unify
220	} else {
221	to.type = from.type->clone();
222	}
223	}
224
225	// unify widening if matches
226	to.allowWidening &= from.allowWidening;
227	return true;
228	}
229
230	// xxx -- this should maybe be worrying about iterator invalidation (see resolv-proto)
231	bool TypeEnvironment::mergeClasses( TypeEnvironment::ClassList::iterator to, TypeEnvironment::ClassList::iterator from, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
232	EqvClass& r = *to;
233	EqvClass& s = *from;
234
235	// ensure bounds match
236	if ( ! mergeBound( r, s, openVars, indexer ) ) return false;
237
238	// check safely bindable
239	if ( r.type && occursIn( r.type, s.vars.begin(), s.vars.end(), *this ) ) return false;
240
241	// merge classes in
242	r.vars.insert( s.vars.begin(), s.vars.end() );
243	r.allowWidening &= s.allowWidening;
244	env.erase( from );
245
246	return true;
247	}
248
249	bool TypeEnvironment::combine( const TypeEnvironment& o, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
250	// short-circuit easy cases
251	if ( o.isEmpty() ) return true;
252	if ( isEmpty() ) {
253	simpleCombine( o );
254	return true;
255	}
256
257	// merge classes
258	for ( auto ct = o.env.begin(); ct != o.env.end(); ++ct ) {
259	const EqvClass& c = *ct;
260
261	// typeclass in local environment bound to c
262	auto rt = env.end();
263
264	// look for first existing bound variable
265	auto vt = c.vars.begin();
266	for ( ; vt != c.vars.end(); ++vt ) {
267	rt = internal_lookup( *vt );
268	if ( rt != env.end() ) break;
269	}
270
271	if ( rt != env.end() ) { // c needs to be merged into *rt
272	EqvClass& r = *rt;
273	// merge bindings
274	if ( ! mergeBound( r, c, openVars, indexer ) ) return false;
275	// merge previous unbound variables into this class, checking occurs if needed
276	if ( r.type ) for ( auto ut = c.vars.begin(); ut != vt; ++ut ) {
277	if ( occurs( r.type, ut, this ) ) return false;
278	r.vars.insert( *ut );
279	} else { r.vars.insert( c.vars.begin(), vt ); }
280	// merge subsequent variables into this class (skipping *vt, already there)
281	while ( ++vt != c.vars.end() ) {
282	auto st = internal_lookup( *vt );
283	if ( st == env.end() ) {
284	// unbound, safe to add if passes occurs
285	if ( r.type && occurs( r.type, vt, this ) ) return false;
286	r.vars.insert( *vt );
287	} else if ( st != rt ) {
288	// bound, but not to the same class
289	if ( ! mergeClasses( rt, st, openVars, indexer ) ) return false;
290	} // ignore bound into the same class
291	}
292	} else { // no variables in c bound; just copy up
293	env.push_back( c );
294	}
295	}
296
297	// merged all classes
298	return true;
299	}
300
301	void TypeEnvironment::extractOpenVars( OpenVarSet &openVars ) const {
302	for ( ClassList::const_iterator eqvClass = env.begin(); eqvClass != env.end(); ++eqvClass ) {
303	for ( std::set< std::string >::const_iterator var = eqvClass->vars.begin(); var != eqvClass->vars.end(); ++var ) {
304	openVars[ *var ] = eqvClass->data;
305	} // for
306	} // for
307	}
308
309	void TypeEnvironment::addActual( const TypeEnvironment& actualEnv, OpenVarSet& openVars ) {
310	for ( const EqvClass& c : actualEnv ) {
311	EqvClass c2 = c;
312	c2.allowWidening = false;
313	for ( const std::string& var : c2.vars ) {
314	openVars[ var ] = c2.data;
315	}
316	env.push_back( std::move(c2) );
317	}
318	}
319
320	bool isFtype( const Type * type ) {
321	if ( dynamic_cast< const FunctionType * >( type ) ) {
322	return true;
323	} else if ( const TypeInstType typeInst = dynamic_cast< const TypeInstType >( type ) ) {
324	return typeInst->get_isFtype();
325	} // if
326	return false;
327	}
328
329	bool tyVarCompatible( const TypeDecl::Data & data, const Type * type ) {
330	switch ( data.kind ) {
331	case TypeDecl::Dtype:
332	// to bind to an object type variable, the type must not be a function type.
333	// if the type variable is specified to be a complete type then the incoming
334	// type must also be complete
335	// xxx - should this also check that type is not a tuple type and that it's not a ttype?
336	return ! isFtype( type ) && (! data.isComplete \|\| type->isComplete() );
337	case TypeDecl::Ftype:
338	return isFtype( type );
339	case TypeDecl::Ttype:
340	// ttype unifies with any tuple type
341	return dynamic_cast< const TupleType * >( type ) \|\| Tuples::isTtype( type );
342	default:
343	assertf(false, "Unhandled tyvar kind: %d", data.kind);
344	} // switch
345	return false;
346	}
347
348	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 ) {
349
350	// remove references from other, so that type variables can only bind to value types
351	bindTo = bindTo->stripReferences();
352	OpenVarSet::const_iterator tyvar = openVars.find( typeInst->get_name() );
353	assert( tyvar != openVars.end() );
354	if ( ! tyVarCompatible( tyvar->second, bindTo ) ) {
355	return false;
356	} // if
357	if ( occurs( bindTo, typeInst->get_name(), *this ) ) {
358	return false;
359	} // if
360	auto curClass = internal_lookup( typeInst->get_name() );
361	if ( curClass != env.end() ) {
362	if ( curClass->type ) {
363	Type *common = 0;
364	// attempt to unify equivalence class type (which has qualifiers stripped, so they must be restored) with the type to bind to
365	std::unique_ptr< Type > newType( curClass->type->clone() );
366	newType->tq = typeInst->tq;
367	if ( unifyInexact( newType.get(), bindTo, *this, need, have, openVars, widen & WidenMode( curClass->allowWidening, true ), indexer, common ) ) {
368	if ( common ) {
369	common->get_qualifiers() = Type::Qualifiers{};
370	curClass->set_type( common );
371	} // if
372	} else return false;
373	} else {
374	Type* newType = bindTo->clone();
375	newType->get_qualifiers() = Type::Qualifiers{};
376	curClass->set_type( newType );
377	curClass->allowWidening = widen.first && widen.second;
378	} // if
379	} else {
380	EqvClass newClass;
381	newClass.vars.insert( typeInst->get_name() );
382	newClass.type = bindTo->clone();
383	newClass.type->get_qualifiers() = Type::Qualifiers();
384	newClass.allowWidening = widen.first && widen.second;
385	newClass.data = data;
386	env.push_back( std::move(newClass) );
387	} // if
388	return true;
389	}
390
391	bool TypeEnvironment::bindVarToVar( const TypeInstType * var1, const TypeInstType * var2,
392	TypeDecl::Data && data, AssertionSet &need, AssertionSet &have,
393	const OpenVarSet &openVars, WidenMode widen, const SymTab::Indexer &indexer ) {
394
395	auto class1 = internal_lookup( var1->get_name() );
396	auto class2 = internal_lookup( var2->get_name() );
397
398	// exit early if variables already bound together
399	if ( class1 != env.end() && class1 == class2 ) {
400	class1->allowWidening &= widen;
401	return true;
402	}
403
404	bool widen1 = false, widen2 = false;
405	const Type type1 = nullptr, type2 = nullptr;
406
407	// check for existing bindings, perform occurs check
408	if ( class1 != env.end() ) {
409	if ( class1->type ) {
410	if ( occurs( class1->type, var2->get_name(), *this ) ) return false;
411	type1 = class1->type;
412	} // if
413	widen1 = widen.first && class1->allowWidening;
414	} // if
415	if ( class2 != env.end() ) {
416	if ( class2->type ) {
417	if ( occurs( class2->type, var1->get_name(), *this ) ) return false;
418	type2 = class2->type;
419	} // if
420	widen2 = widen.second && class2->allowWidening;
421	} // if
422
423	if ( type1 && type2 ) {
424	// both classes bound, merge if bound types can be unified
425	std::unique_ptr<Type> newType1{ type1->clone() }, newType2{ type2->clone() };
426	WidenMode newWidenMode{ widen1, widen2 };
427	Type *common = 0;
428	if ( unifyInexact( newType1.get(), newType2.get(), *this, need, have, openVars, newWidenMode, indexer, common ) ) {
429	class1->vars.insert( class2->vars.begin(), class2->vars.end() );
430	class1->allowWidening = widen1 && widen2;
431	if ( common ) {
432	common->get_qualifiers() = Type::Qualifiers{};
433	class1->set_type( common );
434	}
435	class1->data.isComplete \|= data.isComplete;
436	env.erase( class2 );
437	} else return false;
438	} else if ( class1 != env.end() && class2 != env.end() ) {
439	// both classes exist, at least one unbound, merge unconditionally
440	if ( type1 ) {
441	class1->vars.insert( class2->vars.begin(), class2->vars.end() );
442	class1->allowWidening = widen1;
443	class1->data.isComplete \|= data.isComplete;
444	env.erase( class2 );
445	} else {
446	class2->vars.insert( class1->vars.begin(), class1->vars.end() );
447	class2->allowWidening = widen2;
448	class2->data.isComplete \|= data.isComplete;
449	env.erase( class1 );
450	} // if
451	} else if ( class1 != env.end() ) {
452	// var2 unbound, add to class1
453	class1->vars.insert( var2->get_name() );
454	class1->allowWidening = widen1;
455	class1->data.isComplete \|= data.isComplete;
456	} else if ( class2 != env.end() ) {
457	// var1 unbound, add to class2
458	class2->vars.insert( var1->get_name() );
459	class2->allowWidening = widen2;
460	class2->data.isComplete \|= data.isComplete;
461	} else {
462	// neither var bound, create new class
463	EqvClass newClass;
464	newClass.vars.insert( var1->get_name() );
465	newClass.vars.insert( var2->get_name() );
466	newClass.allowWidening = widen1 && widen2;
467	newClass.data = data;
468	env.push_back( std::move(newClass) );
469	} // if
470	return true;
471	}
472
473	void TypeEnvironment::forbidWidening() {
474	for ( EqvClass& c : env ) c.allowWidening = false;
475	}
476
477	std::ostream & operator<<( std::ostream & out, const TypeEnvironment & env ) {
478	env.print( out );
479	return out;
480	}
481	} // namespace ResolvExpr
482
483	// Local Variables: //
484	// tab-width: 4 //
485	// mode: c++ //
486	// compile-command: "make install" //
487	// End: //

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