source: src/ResolvExpr/TypeEnvironment.cc@ 50202fa

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation new-ast-unique-expr pthread-emulation qualifiedEnum
Last change on this file since 50202fa was cd6a6ff, checked in by Thierry Delisle <tdelisle@…>, 5 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
31namespace 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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