source: src/GenPoly/InstantiateGeneric.cc@ 8dceeb7

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors deferred_resn demangler enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox new-ast new-ast-unique-expr new-env no_list persistent-indexer pthread-emulation qualifiedEnum resolv-new with_gc
Last change on this file since 8dceeb7 was b95fe40, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

Add casts to dtype-static member expressions to prevent loss of type information [fixes #42] [fixes #59]
  • Property mode set to 100644
File size: 21.3 KB
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1//
2// Cforall Version 1.0.0 Copyright (C) 2016 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// InstantiateGeneric.cc --
8//
9// Author : Aaron B. Moss
10// Created On : Thu Aug 04 18:33:00 2016
11// Last Modified By : Aaron B. Moss
12// Last Modified On : Thu Aug 04 18:33:00 2016
13// Update Count : 1
14//
15#include "InstantiateGeneric.h"
16
17#include <cassert> // for assertf, assert
18#include <iterator> // for back_inserter, inserter
19#include <list> // for list, _List_const_iterator
20#include <utility> // for move, pair
21#include <vector> // for vector
22
23#include "Common/PassVisitor.h" // for PassVisitor, WithDeclsToAdd
24#include "Common/ScopedMap.h" // for ScopedMap
25#include "Common/SemanticError.h" // for SemanticError
26#include "Common/UniqueName.h" // for UniqueName
27#include "Common/utility.h" // for deleteAll, cloneAll
28#include "GenPoly.h" // for isPolyType, typesPolyCompatible
29#include "ResolvExpr/typeops.h"
30#include "ScopedSet.h" // for ScopedSet, ScopedSet<>::iterator
31#include "ScrubTyVars.h" // for ScrubTyVars
32#include "SynTree/Declaration.h" // for StructDecl, UnionDecl, TypeDecl
33#include "SynTree/Expression.h" // for TypeExpr, Expression
34#include "SynTree/Mutator.h" // for mutateAll
35#include "SynTree/Type.h" // for StructInstType, UnionInstType
36#include "SynTree/TypeSubstitution.h" // for TypeSubstitution
37#include "SynTree/Visitor.h" // for acceptAll
38
39
40namespace GenPoly {
41
42 /// Abstracts type equality for a list of parameter types
43 struct TypeList {
44 TypeList() : params() {}
45 TypeList( const std::list< Type* > &_params ) : params() { cloneAll(_params, params); }
46 TypeList( std::list< Type* > &&_params ) : params( _params ) {}
47
48 TypeList( const TypeList &that ) : params() { cloneAll(that.params, params); }
49 TypeList( TypeList &&that ) : params( std::move( that.params ) ) {}
50
51 /// Extracts types from a list of TypeExpr*
52 TypeList( const std::list< TypeExpr* >& _params ) : params() {
53 for ( std::list< TypeExpr* >::const_iterator param = _params.begin(); param != _params.end(); ++param ) {
54 params.push_back( (*param)->get_type()->clone() );
55 }
56 }
57
58 TypeList& operator= ( const TypeList &that ) {
59 deleteAll( params );
60
61 params.clear();
62 cloneAll( that.params, params );
63
64 return *this;
65 }
66
67 TypeList& operator= ( TypeList &&that ) {
68 deleteAll( params );
69
70 params = std::move( that.params );
71
72 return *this;
73 }
74
75 ~TypeList() { deleteAll( params ); }
76
77 bool operator== ( const TypeList& that ) const {
78 if ( params.size() != that.params.size() ) return false;
79
80 for ( std::list< Type* >::const_iterator it = params.begin(), jt = that.params.begin(); it != params.end(); ++it, ++jt ) {
81 if ( ! typesPolyCompatible( *it, *jt ) ) return false;
82 }
83 return true;
84 }
85
86 std::list< Type* > params; ///< Instantiation parameters
87 };
88
89 /// Maps a key and a TypeList to the some value, accounting for scope
90 template< typename Key, typename Value >
91 class InstantiationMap {
92 /// Wraps value for a specific (Key, TypeList) combination
93 typedef std::pair< TypeList, Value* > Instantiation;
94 /// List of TypeLists paired with their appropriate values
95 typedef std::vector< Instantiation > ValueList;
96 /// Underlying map type; maps keys to a linear list of corresponding TypeLists and values
97 typedef ScopedMap< Key*, ValueList > InnerMap;
98
99 InnerMap instantiations; ///< instantiations
100
101 public:
102 /// Starts a new scope
103 void beginScope() { instantiations.beginScope(); }
104
105 /// Ends a scope
106 void endScope() { instantiations.endScope(); }
107
108 /// Gets the value for the (key, typeList) pair, returns NULL on none such.
109 Value *lookup( Key *key, const std::list< TypeExpr* >& params ) const {
110 TypeList typeList( params );
111
112 // scan scopes for matches to the key
113 for ( typename InnerMap::const_iterator insts = instantiations.find( key ); insts != instantiations.end(); insts = instantiations.findNext( insts, key ) ) {
114 for ( typename ValueList::const_reverse_iterator inst = insts->second.rbegin(); inst != insts->second.rend(); ++inst ) {
115 if ( inst->first == typeList ) return inst->second;
116 }
117 }
118 // no matching instantiations found
119 return 0;
120 }
121
122 /// Adds a value for a (key, typeList) pair to the current scope
123 void insert( Key *key, const std::list< TypeExpr* > &params, Value *value ) {
124 auto it = instantiations.findAt( instantiations.currentScope(), key );
125 if ( it == instantiations.end() ) {
126 instantiations.insert( key, ValueList{ Instantiation{ TypeList( params ), value } } );
127 } else {
128 it->second.push_back( Instantiation{ TypeList( params ), value } );
129 }
130 }
131 };
132
133 /// Possible options for a given specialization of a generic type
134 enum class genericType {
135 dtypeStatic, ///< Concrete instantiation based solely on {d,f}type-to-void conversions
136 concrete, ///< Concrete instantiation requiring at least one parameter type
137 dynamic ///< No concrete instantiation
138 };
139
140 genericType& operator |= ( genericType& gt, const genericType& ht ) {
141 switch ( gt ) {
142 case genericType::dtypeStatic:
143 gt = ht;
144 break;
145 case genericType::concrete:
146 if ( ht == genericType::dynamic ) { gt = genericType::dynamic; }
147 break;
148 case genericType::dynamic:
149 // nothing possible
150 break;
151 }
152 return gt;
153 }
154
155 /// Add cast to dtype-static member expressions so that type information is not lost in GenericInstantiator
156 struct FixDtypeStatic final {
157 Expression * postmutate( MemberExpr * memberExpr );
158
159 template<typename AggrInst>
160 Expression * fixMemberExpr( AggrInst * inst, MemberExpr * memberExpr );
161 };
162
163 /// Mutator pass that replaces concrete instantiations of generic types with actual struct declarations, scoped appropriately
164 struct GenericInstantiator final : public WithTypeSubstitution, public WithDeclsToAdd, public WithVisitorRef<GenericInstantiator>, public WithGuards {
165 /// Map of (generic type, parameter list) pairs to concrete type instantiations
166 InstantiationMap< AggregateDecl, AggregateDecl > instantiations;
167 /// Set of types which are dtype-only generic (and therefore have static layout)
168 ScopedSet< AggregateDecl* > dtypeStatics;
169 /// Namer for concrete types
170 UniqueName typeNamer;
171 /// Should not make use of type environment to replace types of function parameter and return values.
172 bool inFunctionType = false;
173 /// Index of current member, used to recreate MemberExprs with the member from an instantiation
174 int memberIndex = -1;
175 GenericInstantiator() : instantiations(), dtypeStatics(), typeNamer("_conc_") {}
176
177 Type* postmutate( StructInstType *inst );
178 Type* postmutate( UnionInstType *inst );
179
180 // fix MemberExprs to use the member from the instantiation
181 void premutate( MemberExpr * memberExpr );
182 Expression * postmutate( MemberExpr * memberExpr );
183
184 void premutate( FunctionType * ) {
185 GuardValue( inFunctionType );
186 inFunctionType = true;
187 }
188
189 void beginScope();
190 void endScope();
191 private:
192 /// Wrap instantiation lookup for structs
193 StructDecl* lookup( StructInstType *inst, const std::list< TypeExpr* > &typeSubs ) { return (StructDecl*)instantiations.lookup( inst->get_baseStruct(), typeSubs ); }
194 /// Wrap instantiation lookup for unions
195 UnionDecl* lookup( UnionInstType *inst, const std::list< TypeExpr* > &typeSubs ) { return (UnionDecl*)instantiations.lookup( inst->get_baseUnion(), typeSubs ); }
196 /// Wrap instantiation insertion for structs
197 void insert( StructInstType *inst, const std::list< TypeExpr* > &typeSubs, StructDecl *decl ) { instantiations.insert( inst->get_baseStruct(), typeSubs, decl ); }
198 /// Wrap instantiation insertion for unions
199 void insert( UnionInstType *inst, const std::list< TypeExpr* > &typeSubs, UnionDecl *decl ) { instantiations.insert( inst->get_baseUnion(), typeSubs, decl ); }
200
201 void replaceParametersWithConcrete( std::list< Expression* >& params );
202 Type *replaceWithConcrete( Type *type, bool doClone );
203
204 /// Strips a dtype-static aggregate decl of its type parameters, marks it as stripped
205 void stripDtypeParams( AggregateDecl *base, std::list< TypeDecl* >& baseParams, const std::list< TypeExpr* >& typeSubs );
206 };
207
208 void instantiateGeneric( std::list< Declaration* > &translationUnit ) {
209 PassVisitor<FixDtypeStatic> fixer;
210 PassVisitor<GenericInstantiator> instantiator;
211
212 mutateAll( translationUnit, fixer );
213 mutateAll( translationUnit, instantiator );
214 }
215
216 bool isDtypeStatic( const std::list< TypeDecl* >& baseParams ) {
217 return std::all_of( baseParams.begin(), baseParams.end(), []( TypeDecl * td ) { return ! td->isComplete(); } );
218 }
219
220 /// Makes substitutions of params into baseParams; returns dtypeStatic if there is a concrete instantiation based only on {d,f}type-to-void conversions,
221 /// concrete if there is a concrete instantiation requiring at least one parameter type, and dynamic if there is no concrete instantiation
222 genericType makeSubstitutions( const std::list< TypeDecl* >& baseParams, const std::list< Expression* >& params, std::list< TypeExpr* >& out ) {
223 genericType gt = genericType::dtypeStatic;
224
225 // substitute concrete types for given parameters, and incomplete types for placeholders
226 std::list< TypeDecl* >::const_iterator baseParam = baseParams.begin();
227 std::list< Expression* >::const_iterator param = params.begin();
228 for ( ; baseParam != baseParams.end() && param != params.end(); ++baseParam, ++param ) {
229 TypeExpr *paramType = dynamic_cast< TypeExpr* >( *param );
230 assert(paramType && "Aggregate parameters should be type expressions");
231
232 if ( (*baseParam)->isComplete() ) {
233 // substitute parameter for complete (otype or sized dtype) type
234 if ( isPolyType( paramType->get_type() ) ) {
235 // substitute polymorphic parameter type in to generic type
236 out.push_back( paramType->clone() );
237 gt = genericType::dynamic;
238 } else {
239 // normalize possibly dtype-static parameter type
240 out.push_back( new TypeExpr{
241 ScrubTyVars::scrubAll( paramType->get_type()->clone() ) } );
242 gt |= genericType::concrete;
243 }
244 } else switch ( (*baseParam)->get_kind() ) {
245 case TypeDecl::Dtype:
246 // can pretend that any incomplete dtype is `void`
247 out.push_back( new TypeExpr( new VoidType( Type::Qualifiers() ) ) );
248 break;
249 case TypeDecl::Ftype:
250 // can pretend that any ftype is `void (*)(void)`
251 out.push_back( new TypeExpr( new FunctionType( Type::Qualifiers(), false ) ) );
252 break;
253 case TypeDecl::Ttype:
254 assertf( false, "Ttype parameters are not currently allowed as parameters to generic types." );
255 break;
256 default:
257 assertf( false, "Unhandled type parameter kind" );
258 break;
259 }
260 }
261
262 assertf( baseParam == baseParams.end() && param == params.end(), "Type parameters should match type variables" );
263 return gt;
264 }
265
266 /// Substitutes types of members of in according to baseParams => typeSubs, appending the result to out
267 void substituteMembers( const std::list< Declaration* >& in, const std::list< TypeDecl* >& baseParams, const std::list< TypeExpr* >& typeSubs,
268 std::list< Declaration* >& out ) {
269 // substitute types into new members
270 TypeSubstitution subs( baseParams.begin(), baseParams.end(), typeSubs.begin() );
271 for ( std::list< Declaration* >::const_iterator member = in.begin(); member != in.end(); ++member ) {
272 Declaration *newMember = (*member)->clone();
273 subs.apply(newMember);
274 out.push_back( newMember );
275 }
276 }
277
278 /// Substitutes types of members according to baseParams => typeSubs, working in-place
279 void substituteMembers( std::list< Declaration* >& members, const std::list< TypeDecl* >& baseParams, const std::list< TypeExpr* >& typeSubs ) {
280 // substitute types into new members
281 TypeSubstitution subs( baseParams.begin(), baseParams.end(), typeSubs.begin() );
282 for ( std::list< Declaration* >::iterator member = members.begin(); member != members.end(); ++member ) {
283 subs.apply(*member);
284 }
285 }
286
287 /// Strips the instances's type parameters
288 void stripInstParams( ReferenceToType *inst ) {
289 deleteAll( inst->get_parameters() );
290 inst->get_parameters().clear();
291 }
292
293 void GenericInstantiator::stripDtypeParams( AggregateDecl *base, std::list< TypeDecl* >& baseParams, const std::list< TypeExpr* >& typeSubs ) {
294 substituteMembers( base->get_members(), baseParams, typeSubs );
295
296 // xxx - can't delete type parameters because they may have assertions that are used
297 // deleteAll( baseParams );
298 baseParams.clear();
299
300 dtypeStatics.insert( base );
301 }
302
303 /// xxx - more or less copied from box -- these should be merged with those somehow...
304 void GenericInstantiator::replaceParametersWithConcrete( std::list< Expression* >& params ) {
305 for ( std::list< Expression* >::iterator param = params.begin(); param != params.end(); ++param ) {
306 TypeExpr *paramType = dynamic_cast< TypeExpr* >( *param );
307 assertf(paramType, "Aggregate parameters should be type expressions");
308 paramType->set_type( replaceWithConcrete( paramType->get_type(), false ) );
309 }
310 }
311
312 Type *GenericInstantiator::replaceWithConcrete( Type *type, bool doClone ) {
313 if ( TypeInstType *typeInst = dynamic_cast< TypeInstType * >( type ) ) {
314 if ( env && ! inFunctionType ) {
315 Type *concrete = env->lookup( typeInst->get_name() );
316 if ( concrete ) {
317 return concrete->clone();
318 }
319 else return typeInst->clone();
320 }
321 } else if ( StructInstType *structType = dynamic_cast< StructInstType* >( type ) ) {
322 if ( doClone ) {
323 structType = structType->clone();
324 }
325 replaceParametersWithConcrete( structType->get_parameters() );
326 return structType;
327 } else if ( UnionInstType *unionType = dynamic_cast< UnionInstType* >( type ) ) {
328 if ( doClone ) {
329 unionType = unionType->clone();
330 }
331 replaceParametersWithConcrete( unionType->get_parameters() );
332 return unionType;
333 }
334 return type;
335 }
336
337
338 Type* GenericInstantiator::postmutate( StructInstType *inst ) {
339 // exit early if no need for further mutation
340 if ( inst->get_parameters().empty() ) return inst;
341
342 // need to replace type variables to ensure that generic types are instantiated for the return values of polymorphic functions (in particular, for thunks, because they are not [currently] copy constructed).
343 replaceWithConcrete( inst, false );
344
345 // check for an already-instantiatiated dtype-static type
346 if ( dtypeStatics.find( inst->get_baseStruct() ) != dtypeStatics.end() ) {
347 stripInstParams( inst );
348 return inst;
349 }
350
351 // check if type can be concretely instantiated; put substitutions into typeSubs
352 assertf( inst->get_baseParameters(), "Base struct has parameters" );
353 std::list< TypeExpr* > typeSubs;
354 genericType gt = makeSubstitutions( *inst->get_baseParameters(), inst->get_parameters(), typeSubs );
355 switch ( gt ) {
356 case genericType::dtypeStatic:
357 stripDtypeParams( inst->get_baseStruct(), *inst->get_baseParameters(), typeSubs );
358 stripInstParams( inst );
359 break;
360
361 case genericType::concrete: {
362 // make concrete instantiation of generic type
363 StructDecl *concDecl = lookup( inst, typeSubs );
364 if ( ! concDecl ) {
365 // set concDecl to new type, insert type declaration into statements to add
366 concDecl = new StructDecl( typeNamer.newName( inst->get_name() ) );
367 concDecl->set_body( inst->get_baseStruct()->has_body() );
368 substituteMembers( inst->get_baseStruct()->get_members(), *inst->get_baseParameters(), typeSubs, concDecl->get_members() );
369 insert( inst, typeSubs, concDecl ); // must insert before recursion
370 concDecl->acceptMutator( *visitor ); // recursively instantiate members
371 declsToAddBefore.push_back( concDecl ); // must occur before declaration is added so that member instantiations appear first
372 }
373 StructInstType *newInst = new StructInstType( inst->get_qualifiers(), concDecl->get_name() );
374 newInst->set_baseStruct( concDecl );
375
376 delete inst;
377 inst = newInst;
378 break;
379 }
380
381 case genericType::dynamic:
382 // do nothing
383 break;
384 }
385
386 deleteAll( typeSubs );
387 return inst;
388 }
389
390 Type* GenericInstantiator::postmutate( UnionInstType *inst ) {
391 // exit early if no need for further mutation
392 if ( inst->get_parameters().empty() ) return inst;
393
394 // check for an already-instantiatiated dtype-static type
395 if ( dtypeStatics.find( inst->get_baseUnion() ) != dtypeStatics.end() ) {
396 stripInstParams( inst );
397 return inst;
398 }
399
400 // check if type can be concretely instantiated; put substitutions into typeSubs
401 assert( inst->get_baseParameters() && "Base union has parameters" );
402 std::list< TypeExpr* > typeSubs;
403 genericType gt = makeSubstitutions( *inst->get_baseParameters(), inst->get_parameters(), typeSubs );
404 switch ( gt ) {
405 case genericType::dtypeStatic:
406 stripDtypeParams( inst->get_baseUnion(), *inst->get_baseParameters(), typeSubs );
407 stripInstParams( inst );
408 break;
409
410 case genericType::concrete:
411 {
412 // make concrete instantiation of generic type
413 UnionDecl *concDecl = lookup( inst, typeSubs );
414 if ( ! concDecl ) {
415 // set concDecl to new type, insert type declaration into statements to add
416 concDecl = new UnionDecl( typeNamer.newName( inst->get_name() ) );
417 concDecl->set_body( inst->get_baseUnion()->has_body() );
418 substituteMembers( inst->get_baseUnion()->get_members(), *inst->get_baseParameters(), typeSubs, concDecl->get_members() );
419 insert( inst, typeSubs, concDecl ); // must insert before recursion
420 concDecl->acceptMutator( *visitor ); // recursively instantiate members
421 declsToAddBefore.push_back( concDecl ); // must occur before declaration is added so that member instantiations appear first
422 }
423 UnionInstType *newInst = new UnionInstType( inst->get_qualifiers(), concDecl->get_name() );
424 newInst->set_baseUnion( concDecl );
425
426 delete inst;
427 inst = newInst;
428 break;
429 }
430 case genericType::dynamic:
431 // do nothing
432 break;
433 }
434
435 deleteAll( typeSubs );
436 return inst;
437 }
438
439 namespace {
440 bool isGenericType( Type * t ) {
441 if ( StructInstType * inst = dynamic_cast< StructInstType * >( t ) ) {
442 return ! inst->parameters.empty();
443 } else if ( UnionInstType * inst = dynamic_cast< UnionInstType * >( t ) ) {
444 return ! inst->parameters.empty();
445 }
446 return false;
447 }
448
449 AggregateDecl * getAggr( Type * t ) {
450 if ( StructInstType * inst = dynamic_cast< StructInstType * >( t ) ) {
451 return inst->baseStruct;
452 } else if ( UnionInstType * inst = dynamic_cast< UnionInstType * >( t ) ) {
453 return inst->baseUnion;
454 }
455 assertf( false, "Non-aggregate type: %s", toString( t ).c_str() );
456 }
457 }
458
459 void GenericInstantiator::premutate( MemberExpr * memberExpr ) {
460 GuardValue( memberIndex );
461 memberIndex = -1;
462 if ( isGenericType( memberExpr->aggregate->result ) ) {
463 // find the location of the member
464 AggregateDecl * aggr = getAggr( memberExpr->aggregate->result );
465 std::list< Declaration * > & members = aggr->members;
466 memberIndex = std::distance( members.begin(), std::find( members.begin(), members.end(), memberExpr->member ) );
467 assertf( memberIndex < (int)members.size(), "Could not find member %s in generic type %s", toString( memberExpr->member ).c_str(), toString( memberExpr->aggregate ).c_str() );
468 }
469 }
470
471 Expression * GenericInstantiator::postmutate( MemberExpr * memberExpr ) {
472 if ( memberIndex != -1 ) {
473 // using the location from the generic type, find the member in the instantiation and rebuild the member expression
474 AggregateDecl * aggr = getAggr( memberExpr->aggregate->result );
475 assertf( memberIndex < (int)aggr->members.size(), "Instantiation somehow has fewer members than the generic type." );
476 Declaration * member = *std::next( aggr->members.begin(), memberIndex );
477 assertf( member->name == memberExpr->member->name, "Instantiation has different member order than the generic type. %s / %s", toString( member ).c_str(), toString( memberExpr->member ).c_str() );
478 DeclarationWithType * field = strict_dynamic_cast< DeclarationWithType * >( member );
479 MemberExpr * ret = new MemberExpr( field, memberExpr->aggregate->clone() );
480 std::swap( ret->env, memberExpr->env );
481 delete memberExpr;
482 return ret;
483 }
484 return memberExpr;
485 }
486
487 void GenericInstantiator::beginScope() {
488 instantiations.beginScope();
489 dtypeStatics.beginScope();
490 }
491
492 void GenericInstantiator::endScope() {
493 instantiations.endScope();
494 dtypeStatics.endScope();
495 }
496
497 template< typename AggrInst >
498 Expression * FixDtypeStatic::fixMemberExpr( AggrInst * inst, MemberExpr * memberExpr ) {
499 // need to cast dtype-static member expressions to their actual type before that type is erased.
500 auto & baseParams = *inst->get_baseParameters();
501 if ( isDtypeStatic( baseParams ) ) {
502 if ( ! ResolvExpr::typesCompatible( memberExpr->result, memberExpr->member->get_type(), SymTab::Indexer() ) ) {
503 // type of member and type of expression differ, so add cast to actual type
504 return new CastExpr( memberExpr, memberExpr->result->clone() );
505 }
506 }
507 return memberExpr;
508 }
509
510 Expression * FixDtypeStatic::postmutate( MemberExpr * memberExpr ) {
511 Type * aggrType = memberExpr->aggregate->result;
512 if ( isGenericType( aggrType ) ) {
513 if ( StructInstType * inst = dynamic_cast< StructInstType * >( aggrType ) ) {
514 return fixMemberExpr( inst, memberExpr );
515 } else if ( UnionInstType * inst = dynamic_cast< UnionInstType * >( aggrType ) ) {
516 return fixMemberExpr( inst, memberExpr );
517 }
518 }
519 return memberExpr;
520 }
521
522} // namespace GenPoly
523
524// Local Variables: //
525// tab-width: 4 //
526// mode: c++ //
527// compile-command: "make install" //
528// End: //
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