source: src/ResolvExpr/TypeEnvironment.cc@ 3b9c674

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox new-ast new-ast-unique-expr pthread-emulation qualifiedEnum
Last change on this file since 3b9c674 was fd642d2, checked in by Andrew Beach <ajbeach@…>, 6 years ago

Added const in a few more places. This should be all the leaf areas need to make unify const.
  • Property mode set to 100644
File size: 16.3 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 "Common/utility.h" // for maybeClone
23#include "SynTree/Type.h" // for Type, FunctionType, Type::Fora...
24#include "SynTree/TypeSubstitution.h" // for TypeSubstitution
25#include "Tuples/Tuples.h" // for isTtype
26#include "TypeEnvironment.h"
27#include "typeops.h" // for occurs
28#include "Unify.h" // for unifyInexact
29
30namespace ResolvExpr {
31 void printAssertionSet( const AssertionSet &assertions, std::ostream &os, int indent ) {
32 for ( AssertionSet::const_iterator i = assertions.begin(); i != assertions.end(); ++i ) {
33 i->first->print( os, indent );
34 if ( i->second.isUsed ) {
35 os << "(used)";
36 } else {
37 os << "(not used)";
38 } // if
39 } // for
40 }
41
42 void printOpenVarSet( const OpenVarSet &openVars, std::ostream &os, int indent ) {
43 os << std::string( indent, ' ' );
44 for ( OpenVarSet::const_iterator i = openVars.begin(); i != openVars.end(); ++i ) {
45 os << i->first << "(" << i->second << ") ";
46 } // for
47 }
48
49 void EqvClass::initialize( const EqvClass &src, EqvClass &dest ) {
50 initialize( src, dest, src.type );
51 }
52
53 void EqvClass::initialize( const EqvClass &src, EqvClass &dest, const Type *ty ) {
54 dest.vars = src.vars;
55 dest.type = maybeClone( ty );
56 dest.allowWidening = src.allowWidening;
57 dest.data = src.data;
58 }
59
60 EqvClass::EqvClass() : type( nullptr ), allowWidening( true ) {
61 }
62
63 EqvClass::EqvClass( const EqvClass &other ) {
64 initialize( other, *this );
65 }
66
67 EqvClass::EqvClass( const EqvClass &other, const Type *ty ) {
68 initialize( other, *this, ty );
69 }
70
71 EqvClass::EqvClass( EqvClass &&other )
72 : vars{std::move(other.vars)}, type{other.type},
73 allowWidening{std::move(other.allowWidening)}, data{std::move(other.data)} {
74 other.type = nullptr;
75 }
76
77 EqvClass &EqvClass::operator=( const EqvClass &other ) {
78 if ( this == &other ) return *this;
79 delete type;
80 initialize( other, *this );
81 return *this;
82 }
83
84 EqvClass &EqvClass::operator=( EqvClass &&other ) {
85 if ( this == &other ) return *this;
86 delete type;
87
88 vars = std::move(other.vars);
89 type = other.type;
90 other.type = nullptr;
91 allowWidening = std::move(other.allowWidening);
92 data = std::move(other.data);
93
94 return *this;
95 }
96
97 EqvClass::~EqvClass() {
98 delete type;
99 }
100
101 void EqvClass::set_type( Type* ty ) {
102 if ( ty == type ) return;
103 delete type;
104 type = ty;
105 }
106
107 void EqvClass::print( std::ostream &os, Indenter indent ) const {
108 os << "( ";
109 std::copy( vars.begin(), vars.end(), std::ostream_iterator< std::string >( os, " " ) );
110 os << ")";
111 if ( type ) {
112 os << " -> ";
113 type->print( os, indent+1 );
114 } // if
115 if ( ! allowWidening ) {
116 os << " (no widening)";
117 } // if
118 os << std::endl;
119 }
120
121 const EqvClass* TypeEnvironment::lookup( const std::string &var ) const {
122 for ( ClassList::const_iterator i = env.begin(); i != env.end(); ++i ) {
123 if ( i->vars.find( var ) != i->vars.end() ) return &*i;
124 } // for
125 return nullptr;
126 }
127
128 /// Removes any class from env that intersects eqvClass
129 void filterOverlappingClasses( std::list<EqvClass> &env, const EqvClass &eqvClass ) {
130 for ( auto i = env.begin(); i != env.end(); ) {
131 auto next = i;
132 ++next;
133 std::set<std::string> intersection;
134 std::set_intersection( i->vars.begin(), i->vars.end(), eqvClass.vars.begin(), eqvClass.vars.end(),
135 std::inserter( intersection, intersection.begin() ) );
136 if ( ! intersection.empty() ) { env.erase( i ); }
137 i = next;
138 }
139 }
140
141 void TypeEnvironment::add( EqvClass &&eqvClass ) {
142 filterOverlappingClasses( env, eqvClass );
143 env.push_back( std::move(eqvClass) );
144 }
145
146 void TypeEnvironment::add( const Type::ForallList &tyDecls ) {
147 for ( Type::ForallList::const_iterator i = tyDecls.begin(); i != tyDecls.end(); ++i ) {
148 EqvClass newClass;
149 newClass.vars.insert( (*i)->get_name() );
150 newClass.data = TypeDecl::Data{ (*i) };
151 env.push_back( std::move(newClass) );
152 } // for
153 }
154
155 void TypeEnvironment::add( const TypeSubstitution & sub ) {
156 EqvClass newClass;
157 for ( auto p : sub ) {
158 newClass.vars.insert( p.first );
159 newClass.type = p.second->clone();
160 newClass.allowWidening = false;
161 // Minimal assumptions. Not technically correct, but might be good enough, and
162 // is the best we can do at the moment since information is lost in the
163 // transition to TypeSubstitution
164 newClass.data = TypeDecl::Data{ TypeDecl::Dtype, false };
165 add( std::move(newClass) );
166 }
167 }
168
169 void TypeEnvironment::makeSubstitution( TypeSubstitution &sub ) const {
170 for ( ClassList::const_iterator theClass = env.begin(); theClass != env.end(); ++theClass ) {
171 for ( std::set< std::string >::const_iterator theVar = theClass->vars.begin(); theVar != theClass->vars.end(); ++theVar ) {
172 if ( theClass->type ) {
173 sub.add( *theVar, theClass->type );
174 } else if ( theVar != theClass->vars.begin() ) {
175 TypeInstType *newTypeInst = new TypeInstType( Type::Qualifiers(), *theClass->vars.begin(), theClass->data.kind == TypeDecl::Ftype );
176 sub.add( *theVar, newTypeInst );
177 delete newTypeInst;
178 } // if
179 } // for
180 } // for
181 sub.normalize();
182 }
183
184 void TypeEnvironment::print( std::ostream &os, Indenter indent ) const {
185 for ( const EqvClass & theClass : env ) {
186 theClass.print( os, indent );
187 } // for
188 }
189
190 TypeEnvironment::ClassList::iterator TypeEnvironment::internal_lookup( const std::string &var ) {
191 for ( ClassList::iterator i = env.begin(); i != env.end(); ++i ) {
192 if ( i->vars.count( var ) ) return i;
193 } // for
194 return env.end();
195 }
196
197 void TypeEnvironment::simpleCombine( const TypeEnvironment &second ) {
198 env.insert( env.end(), second.env.begin(), second.env.end() );
199 }
200
201 // xxx -- this should maybe be worrying about iterator invalidation (see resolv-proto)
202 bool TypeEnvironment::mergeBound( EqvClass& to, const EqvClass& from, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
203 if ( from.type ) {
204 if ( to.type ) {
205 // attempt to unify bound types
206 std::unique_ptr<Type> toType{ to.type->clone() }, fromType{ from.type->clone() };
207 WidenMode widen{ to.allowWidening, from.allowWidening };
208 Type* common = nullptr;
209 AssertionSet need, have;
210 if ( unifyInexact( toType.get(), fromType.get(), *this, need, have, openVars, widen, indexer, common ) ) {
211 // unifies, set common type if necessary
212 if ( common ) {
213 common->get_qualifiers() = Type::Qualifiers{};
214 to.set_type( common );
215 }
216 } else return false; // cannot unify
217 } else {
218 to.type = from.type->clone();
219 }
220 }
221
222 // unify widening if matches
223 to.allowWidening &= from.allowWidening;
224 return true;
225 }
226
227 // xxx -- this should maybe be worrying about iterator invalidation (see resolv-proto)
228 bool TypeEnvironment::mergeClasses( TypeEnvironment::ClassList::iterator to, TypeEnvironment::ClassList::iterator from, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
229 EqvClass& r = *to;
230 EqvClass& s = *from;
231
232 // ensure bounds match
233 if ( ! mergeBound( r, s, openVars, indexer ) ) return false;
234
235 // check safely bindable
236 if ( r.type && occursIn( r.type, s.vars.begin(), s.vars.end(), *this ) ) return false;
237
238 // merge classes in
239 r.vars.insert( s.vars.begin(), s.vars.end() );
240 r.allowWidening &= s.allowWidening;
241 env.erase( from );
242
243 return true;
244 }
245
246 bool TypeEnvironment::combine( const TypeEnvironment& o, OpenVarSet& openVars, const SymTab::Indexer& indexer ) {
247 // short-circuit easy cases
248 if ( o.isEmpty() ) return true;
249 if ( isEmpty() ) {
250 simpleCombine( o );
251 return true;
252 }
253
254 // merge classes
255 for ( auto ct = o.env.begin(); ct != o.env.end(); ++ct ) {
256 const EqvClass& c = *ct;
257
258 // typeclass in local environment bound to c
259 auto rt = env.end();
260
261 // look for first existing bound variable
262 auto vt = c.vars.begin();
263 for ( ; vt != c.vars.end(); ++vt ) {
264 rt = internal_lookup( *vt );
265 if ( rt != env.end() ) break;
266 }
267
268 if ( rt != env.end() ) { // c needs to be merged into *rt
269 EqvClass& r = *rt;
270 // merge bindings
271 if ( ! mergeBound( r, c, openVars, indexer ) ) return false;
272 // merge previous unbound variables into this class, checking occurs if needed
273 if ( r.type ) for ( auto ut = c.vars.begin(); ut != vt; ++ut ) {
274 if ( occurs( r.type, *ut, *this ) ) return false;
275 r.vars.insert( *ut );
276 } else { r.vars.insert( c.vars.begin(), vt ); }
277 // merge subsequent variables into this class (skipping *vt, already there)
278 while ( ++vt != c.vars.end() ) {
279 auto st = internal_lookup( *vt );
280 if ( st == env.end() ) {
281 // unbound, safe to add if passes occurs
282 if ( r.type && occurs( r.type, *vt, *this ) ) return false;
283 r.vars.insert( *vt );
284 } else if ( st != rt ) {
285 // bound, but not to the same class
286 if ( ! mergeClasses( rt, st, openVars, indexer ) ) return false;
287 } // ignore bound into the same class
288 }
289 } else { // no variables in c bound; just copy up
290 env.push_back( c );
291 }
292 }
293
294 // merged all classes
295 return true;
296 }
297
298 void TypeEnvironment::extractOpenVars( OpenVarSet &openVars ) const {
299 for ( ClassList::const_iterator eqvClass = env.begin(); eqvClass != env.end(); ++eqvClass ) {
300 for ( std::set< std::string >::const_iterator var = eqvClass->vars.begin(); var != eqvClass->vars.end(); ++var ) {
301 openVars[ *var ] = eqvClass->data;
302 } // for
303 } // for
304 }
305
306 void TypeEnvironment::addActual( const TypeEnvironment& actualEnv, OpenVarSet& openVars ) {
307 for ( const EqvClass& c : actualEnv ) {
308 EqvClass c2 = c;
309 c2.allowWidening = false;
310 for ( const std::string& var : c2.vars ) {
311 openVars[ var ] = c2.data;
312 }
313 env.push_back( std::move(c2) );
314 }
315 }
316
317 bool isFtype( const Type * type ) {
318 if ( dynamic_cast< const FunctionType * >( type ) ) {
319 return true;
320 } else if ( const TypeInstType *typeInst = dynamic_cast< const TypeInstType * >( type ) ) {
321 return typeInst->get_isFtype();
322 } // if
323 return false;
324 }
325
326 bool tyVarCompatible( const TypeDecl::Data & data, const Type * type ) {
327 switch ( data.kind ) {
328 case TypeDecl::Dtype:
329 // to bind to an object type variable, the type must not be a function type.
330 // if the type variable is specified to be a complete type then the incoming
331 // type must also be complete
332 // xxx - should this also check that type is not a tuple type and that it's not a ttype?
333 return ! isFtype( type ) && (! data.isComplete || type->isComplete() );
334 case TypeDecl::Ftype:
335 return isFtype( type );
336 case TypeDecl::Ttype:
337 // ttype unifies with any tuple type
338 return dynamic_cast< const TupleType * >( type ) || Tuples::isTtype( type );
339 default:
340 assertf(false, "Unhandled tyvar kind: %d", data.kind);
341 } // switch
342 return false;
343 }
344
345 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 ) {
346
347 // remove references from other, so that type variables can only bind to value types
348 bindTo = bindTo->stripReferences();
349 OpenVarSet::const_iterator tyvar = openVars.find( typeInst->get_name() );
350 assert( tyvar != openVars.end() );
351 if ( ! tyVarCompatible( tyvar->second, bindTo ) ) {
352 return false;
353 } // if
354 if ( occurs( bindTo, typeInst->get_name(), *this ) ) {
355 return false;
356 } // if
357 auto curClass = internal_lookup( typeInst->get_name() );
358 if ( curClass != env.end() ) {
359 if ( curClass->type ) {
360 Type *common = 0;
361 // attempt to unify equivalence class type (which has qualifiers stripped, so they must be restored) with the type to bind to
362 std::unique_ptr< Type > newType( curClass->type->clone() );
363 newType->tq = typeInst->tq;
364 if ( unifyInexact( newType.get(), bindTo, *this, need, have, openVars, widen & WidenMode( curClass->allowWidening, true ), indexer, common ) ) {
365 if ( common ) {
366 common->get_qualifiers() = Type::Qualifiers{};
367 curClass->set_type( common );
368 } // if
369 } else return false;
370 } else {
371 Type* newType = bindTo->clone();
372 newType->get_qualifiers() = Type::Qualifiers{};
373 curClass->set_type( newType );
374 curClass->allowWidening = widen.first && widen.second;
375 } // if
376 } else {
377 EqvClass newClass;
378 newClass.vars.insert( typeInst->get_name() );
379 newClass.type = bindTo->clone();
380 newClass.type->get_qualifiers() = Type::Qualifiers();
381 newClass.allowWidening = widen.first && widen.second;
382 newClass.data = data;
383 env.push_back( std::move(newClass) );
384 } // if
385 return true;
386 }
387
388 bool TypeEnvironment::bindVarToVar( const TypeInstType * var1, const TypeInstType * var2,
389 TypeDecl::Data && data, AssertionSet &need, AssertionSet &have,
390 const OpenVarSet &openVars, WidenMode widen, const SymTab::Indexer &indexer ) {
391
392 auto class1 = internal_lookup( var1->get_name() );
393 auto class2 = internal_lookup( var2->get_name() );
394
395 // exit early if variables already bound together
396 if ( class1 != env.end() && class1 == class2 ) {
397 class1->allowWidening &= widen;
398 return true;
399 }
400
401 bool widen1 = false, widen2 = false;
402 const Type *type1 = nullptr, *type2 = nullptr;
403
404 // check for existing bindings, perform occurs check
405 if ( class1 != env.end() ) {
406 if ( class1->type ) {
407 if ( occurs( class1->type, var2->get_name(), *this ) ) return false;
408 type1 = class1->type;
409 } // if
410 widen1 = widen.first && class1->allowWidening;
411 } // if
412 if ( class2 != env.end() ) {
413 if ( class2->type ) {
414 if ( occurs( class2->type, var1->get_name(), *this ) ) return false;
415 type2 = class2->type;
416 } // if
417 widen2 = widen.second && class2->allowWidening;
418 } // if
419
420 if ( type1 && type2 ) {
421 // both classes bound, merge if bound types can be unified
422 std::unique_ptr<Type> newType1{ type1->clone() }, newType2{ type2->clone() };
423 WidenMode newWidenMode{ widen1, widen2 };
424 Type *common = 0;
425 if ( unifyInexact( newType1.get(), newType2.get(), *this, need, have, openVars, newWidenMode, indexer, common ) ) {
426 class1->vars.insert( class2->vars.begin(), class2->vars.end() );
427 class1->allowWidening = widen1 && widen2;
428 if ( common ) {
429 common->get_qualifiers() = Type::Qualifiers{};
430 class1->set_type( common );
431 }
432 class1->data.isComplete |= data.isComplete;
433 env.erase( class2 );
434 } else return false;
435 } else if ( class1 != env.end() && class2 != env.end() ) {
436 // both classes exist, at least one unbound, merge unconditionally
437 if ( type1 ) {
438 class1->vars.insert( class2->vars.begin(), class2->vars.end() );
439 class1->allowWidening = widen1;
440 class1->data.isComplete |= data.isComplete;
441 env.erase( class2 );
442 } else {
443 class2->vars.insert( class1->vars.begin(), class1->vars.end() );
444 class2->allowWidening = widen2;
445 class2->data.isComplete |= data.isComplete;
446 env.erase( class1 );
447 } // if
448 } else if ( class1 != env.end() ) {
449 // var2 unbound, add to class1
450 class1->vars.insert( var2->get_name() );
451 class1->allowWidening = widen1;
452 class1->data.isComplete |= data.isComplete;
453 } else if ( class2 != env.end() ) {
454 // var1 unbound, add to class2
455 class2->vars.insert( var1->get_name() );
456 class2->allowWidening = widen2;
457 class2->data.isComplete |= data.isComplete;
458 } else {
459 // neither var bound, create new class
460 EqvClass newClass;
461 newClass.vars.insert( var1->get_name() );
462 newClass.vars.insert( var2->get_name() );
463 newClass.allowWidening = widen1 && widen2;
464 newClass.data = data;
465 env.push_back( std::move(newClass) );
466 } // if
467 return true;
468 }
469
470 void TypeEnvironment::forbidWidening() {
471 for ( EqvClass& c : env ) c.allowWidening = false;
472 }
473
474 std::ostream & operator<<( std::ostream & out, const TypeEnvironment & env ) {
475 env.print( out );
476 return out;
477 }
478} // namespace ResolvExpr
479
480// Local Variables: //
481// tab-width: 4 //
482// mode: c++ //
483// compile-command: "make install" //
484// End: //
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