source: src/Tuples/TupleAssignment.cc@ 32d6fdc

ADT ast-experimental
Last change on this file since 32d6fdc was 39d8950, checked in by Andrew Beach <ajbeach@…>, 4 years ago

Thread global information through resolution. Non-top-level calls to the resolver have a bit of a hack but improvements would require changes to the Pass helpers.
  • Property mode set to 100644
File size: 27.4 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// TupleAssignment.cc --
8//
9// Author : Rodolfo G. Esteves
10// Created On : Mon May 18 07:44:20 2015
11// Last Modified By : Andrew Beach
12// Last Modified On : Wed Mar 16 14:06:00 2022
13// Update Count : 10
14//
15
16#include <algorithm> // for transform
17#include <cassert> // for assert
18#include <iterator> // for back_insert_iterator, back...
19#include <list> // for _List_const_iterator, _Lis...
20#include <memory> // for unique_ptr, allocator_trai...
21#include <string> // for string
22#include <vector>
23
24#include "AST/Decl.hpp"
25#include "AST/Init.hpp"
26#include "AST/Pass.hpp"
27#include "AST/Stmt.hpp"
28#include "AST/TypeEnvironment.hpp"
29#include "CodeGen/OperatorTable.h"
30#include "Common/PassVisitor.h"
31#include "Common/UniqueName.h" // for UniqueName
32#include "Common/utility.h" // for splice, zipWith
33#include "Explode.h" // for explode
34#include "InitTweak/GenInit.h" // for genCtorInit
35#include "InitTweak/InitTweak.h" // for getPointerBase, isAssignment
36#include "ResolvExpr/Alternative.h" // for AltList, Alternative
37#include "ResolvExpr/AlternativeFinder.h" // for AlternativeFinder, simpleC...
38#include "ResolvExpr/Cost.h" // for Cost
39#include "ResolvExpr/Resolver.h" // for resolveCtorInit
40#include "ResolvExpr/TypeEnvironment.h" // for TypeEnvironment
41#include "ResolvExpr/typeops.h" // for combos
42#include "SynTree/LinkageSpec.h" // for Cforall
43#include "SynTree/Declaration.h" // for ObjectDecl
44#include "SynTree/Expression.h" // for Expression, CastExpr, Name...
45#include "SynTree/Initializer.h" // for ConstructorInit, SingleInit
46#include "SynTree/Statement.h" // for ExprStmt
47#include "SynTree/Type.h" // for Type, Type::Qualifiers
48#include "SynTree/TypeSubstitution.h" // for TypeSubstitution
49#include "SynTree/Visitor.h" // for Visitor
50
51#if 0
52#define PRINT(x) x
53#else
54#define PRINT(x)
55#endif
56
57namespace Tuples {
58 class TupleAssignSpotter_old {
59 public:
60 // dispatcher for Tuple (multiple and mass) assignment operations
61 TupleAssignSpotter_old( ResolvExpr::AlternativeFinder & );
62 void spot( UntypedExpr * expr, std::vector<ResolvExpr::AlternativeFinder> &args );
63
64 private:
65 void match();
66
67 struct Matcher {
68 public:
69 Matcher( TupleAssignSpotter_old &spotter, const ResolvExpr::AltList& lhs,
70 const ResolvExpr::AltList& rhs );
71 virtual ~Matcher() {}
72
73 virtual void match( std::list< Expression * > &out ) = 0;
74 ObjectDecl * newObject( UniqueName & namer, Expression * expr );
75
76 void combineState( const ResolvExpr::Alternative& alt ) {
77 compositeEnv.simpleCombine( alt.env );
78 ResolvExpr::mergeOpenVars( openVars, alt.openVars );
79 cloneAll( alt.need, need );
80 }
81
82 void combineState( const ResolvExpr::AltList& alts ) {
83 for ( const ResolvExpr::Alternative& alt : alts ) { combineState( alt ); }
84 }
85
86 ResolvExpr::AltList lhs, rhs;
87 TupleAssignSpotter_old &spotter;
88 ResolvExpr::Cost baseCost;
89 std::list< ObjectDecl * > tmpDecls;
90 ResolvExpr::TypeEnvironment compositeEnv;
91 ResolvExpr::OpenVarSet openVars;
92 ResolvExpr::AssertionSet need;
93 };
94
95 struct MassAssignMatcher : public Matcher {
96 public:
97 MassAssignMatcher( TupleAssignSpotter_old &spotter, const ResolvExpr::AltList& lhs,
98 const ResolvExpr::AltList& rhs ) : Matcher(spotter, lhs, rhs) {}
99 virtual void match( std::list< Expression * > &out );
100 };
101
102 struct MultipleAssignMatcher : public Matcher {
103 public:
104 MultipleAssignMatcher( TupleAssignSpotter_old &spotter, const ResolvExpr::AltList& lhs,
105 const ResolvExpr::AltList& rhs ) : Matcher(spotter, lhs, rhs) {}
106 virtual void match( std::list< Expression * > &out );
107 };
108
109 ResolvExpr::AlternativeFinder &currentFinder;
110 std::string fname;
111 std::unique_ptr< Matcher > matcher;
112 };
113
114 /// true if expr is an expression of tuple type
115 bool isTuple( Expression *expr ) {
116 if ( ! expr ) return false;
117 assert( expr->result );
118 return dynamic_cast< TupleType * >( expr->get_result()->stripReferences() );
119 }
120
121 template< typename AltIter >
122 bool isMultAssign( AltIter begin, AltIter end ) {
123 // multiple assignment if more than one alternative in the range or if
124 // the alternative is a tuple
125 if ( begin == end ) return false;
126 if ( isTuple( begin->expr ) ) return true;
127 return ++begin != end;
128 }
129
130 bool refToTuple( Expression *expr ) {
131 assert( expr->get_result() );
132 // also check for function returning tuple of reference types
133 if ( CastExpr * castExpr = dynamic_cast< CastExpr * >( expr ) ) {
134 return refToTuple( castExpr->get_arg() );
135 } else {
136 return isTuple( expr );
137 }
138 return false;
139 }
140
141 void handleTupleAssignment( ResolvExpr::AlternativeFinder & currentFinder, UntypedExpr * expr,
142 std::vector<ResolvExpr::AlternativeFinder> &args ) {
143 TupleAssignSpotter_old spotter( currentFinder );
144 spotter.spot( expr, args );
145 }
146
147 TupleAssignSpotter_old::TupleAssignSpotter_old( ResolvExpr::AlternativeFinder &f )
148 : currentFinder(f) {}
149
150 void TupleAssignSpotter_old::spot( UntypedExpr * expr,
151 std::vector<ResolvExpr::AlternativeFinder> &args ) {
152 if ( NameExpr *op = dynamic_cast< NameExpr * >(expr->get_function()) ) {
153 if ( CodeGen::isCtorDtorAssign( op->get_name() ) ) {
154 fname = op->get_name();
155
156 // AlternativeFinder will naturally handle this case case, if it's legal
157 if ( args.size() == 0 ) return;
158
159 // if an assignment only takes 1 argument, that's odd, but maybe someone wrote
160 // the function, in which case AlternativeFinder will handle it normally
161 if ( args.size() == 1 && CodeGen::isAssignment( fname ) ) return;
162
163 // look over all possible left-hand-sides
164 for ( ResolvExpr::Alternative& lhsAlt : args[0] ) {
165 // skip non-tuple LHS
166 if ( ! refToTuple(lhsAlt.expr) ) continue;
167
168 // explode is aware of casts - ensure every LHS expression is sent into explode
169 // with a reference cast
170 // xxx - this seems to change the alternatives before the normal
171 // AlternativeFinder flow; maybe this is desired?
172 if ( ! dynamic_cast<CastExpr*>( lhsAlt.expr ) ) {
173 lhsAlt.expr = new CastExpr( lhsAlt.expr,
174 new ReferenceType( Type::Qualifiers(),
175 lhsAlt.expr->result->clone() ) );
176 }
177
178 // explode the LHS so that each field of a tuple-valued-expr is assigned
179 ResolvExpr::AltList lhs;
180 explode( lhsAlt, currentFinder.get_indexer(), back_inserter(lhs), true );
181 for ( ResolvExpr::Alternative& alt : lhs ) {
182 // each LHS value must be a reference - some come in with a cast expression,
183 // if not just cast to reference here
184 if ( ! dynamic_cast<ReferenceType*>( alt.expr->get_result() ) ) {
185 alt.expr = new CastExpr( alt.expr,
186 new ReferenceType( Type::Qualifiers(),
187 alt.expr->get_result()->clone() ) );
188 }
189 }
190
191 if ( args.size() == 1 ) {
192 // mass default-initialization/destruction
193 ResolvExpr::AltList rhs{};
194 matcher.reset( new MassAssignMatcher( *this, lhs, rhs ) );
195 match();
196 } else if ( args.size() > 2 ) {
197 // expand all possible RHS possibilities
198 // TODO build iterative version of this instead of using combos
199 std::vector< ResolvExpr::AltList > rhsAlts;
200 combos( std::next(args.begin(), 1), args.end(),
201 std::back_inserter( rhsAlts ) );
202 for ( const ResolvExpr::AltList& rhsAlt : rhsAlts ) {
203 // multiple assignment
204 ResolvExpr::AltList rhs;
205 explode( rhsAlt, currentFinder.get_indexer(),
206 std::back_inserter(rhs), true );
207 matcher.reset( new MultipleAssignMatcher( *this, lhs, rhs ) );
208 match();
209 }
210 } else {
211 for ( const ResolvExpr::Alternative& rhsAlt : args[1] ) {
212 ResolvExpr::AltList rhs;
213 if ( isTuple(rhsAlt.expr) ) {
214 // multiple assignment
215 explode( rhsAlt, currentFinder.get_indexer(),
216 std::back_inserter(rhs), true );
217 matcher.reset( new MultipleAssignMatcher( *this, lhs, rhs ) );
218 } else {
219 // mass assignment
220 rhs.push_back( rhsAlt );
221 matcher.reset( new MassAssignMatcher( *this, lhs, rhs ) );
222 }
223 match();
224 }
225 }
226 }
227 }
228 }
229 }
230
231 void TupleAssignSpotter_old::match() {
232 assert ( matcher != 0 );
233
234 std::list< Expression * > new_assigns;
235 matcher->match( new_assigns );
236
237 if ( ! matcher->lhs.empty() || ! matcher->rhs.empty() ) {
238 // if both lhs and rhs are empty then this is the empty tuple case, wherein it's okay for new_assigns to be empty.
239 // if not the empty tuple case, return early so that no new alternatives are generated.
240 if ( new_assigns.empty() ) return;
241 }
242 ResolvExpr::AltList current;
243 // now resolve new assignments
244 for ( std::list< Expression * >::iterator i = new_assigns.begin();
245 i != new_assigns.end(); ++i ) {
246 PRINT(
247 std::cerr << "== resolving tuple assign ==" << std::endl;
248 std::cerr << *i << std::endl;
249 )
250
251 ResolvExpr::AlternativeFinder finder{ currentFinder.get_indexer(),
252 matcher->compositeEnv };
253
254 try {
255 finder.findWithAdjustment(*i);
256 } catch (...) {
257 return; // no match should not mean failure, it just means this particular tuple assignment isn't valid
258 }
259 // prune expressions that don't coincide with
260 ResolvExpr::AltList alts = finder.get_alternatives();
261 assert( alts.size() == 1 );
262 assert( alts.front().expr != 0 );
263 current.push_back( alts.front() );
264 }
265
266 // extract expressions from the assignment alternatives to produce a list of assignments
267 // that together form a single alternative
268 std::list< Expression *> solved_assigns;
269 for ( ResolvExpr::Alternative & alt : current ) {
270 solved_assigns.push_back( alt.expr->clone() );
271 matcher->combineState( alt );
272 }
273
274 // xxx -- was push_front
275 currentFinder.get_alternatives().push_back( ResolvExpr::Alternative{
276 new TupleAssignExpr{ solved_assigns, matcher->tmpDecls }, matcher->compositeEnv,
277 matcher->openVars,
278 ResolvExpr::AssertionList( matcher->need.begin(), matcher->need.end() ),
279 ResolvExpr::sumCost( current ) + matcher->baseCost } );
280 }
281
282 TupleAssignSpotter_old::Matcher::Matcher( TupleAssignSpotter_old &spotter,
283 const ResolvExpr::AltList &lhs, const ResolvExpr::AltList &rhs )
284 : lhs(lhs), rhs(rhs), spotter(spotter),
285 baseCost( ResolvExpr::sumCost( lhs ) + ResolvExpr::sumCost( rhs ) ) {
286 combineState( lhs );
287 combineState( rhs );
288 }
289
290 UntypedExpr * createFunc( const std::string &fname, ObjectDecl *left, ObjectDecl *right ) {
291 assert( left );
292 std::list< Expression * > args;
293 args.push_back( new VariableExpr( left ) );
294 // args.push_back( new AddressExpr( new VariableExpr( left ) ) );
295 if ( right ) args.push_back( new VariableExpr( right ) );
296 if ( left->type->referenceDepth() > 1 && CodeGen::isConstructor( fname ) ) {
297 args.front() = new AddressExpr( args.front() );
298 if ( right ) args.back() = new AddressExpr( args.back() );
299 return new UntypedExpr( new NameExpr( "?=?" ), args );
300 } else {
301 return new UntypedExpr( new NameExpr( fname ), args );
302 }
303 }
304
305 // removes environments from subexpressions within statement exprs, which could throw off later passes like those in Box which rely on PolyMutator, and adds the bindings to the compositeEnv
306 // xxx - maybe this should happen in alternative finder for every StmtExpr?
307 struct EnvRemover {
308 void previsit( ExprStmt * stmt ) {
309 assert( compositeEnv );
310 if ( stmt->expr->env ) {
311 compositeEnv->add( *stmt->expr->env );
312 delete stmt->expr->env;
313 stmt->expr->env = nullptr;
314 }
315 }
316
317 ResolvExpr::TypeEnvironment * compositeEnv = nullptr;
318 };
319
320 ObjectDecl * TupleAssignSpotter_old::Matcher::newObject( UniqueName & namer, Expression * expr ) {
321 assert( expr->result && ! expr->get_result()->isVoid() );
322 ObjectDecl * ret = new ObjectDecl( namer.newName(), Type::StorageClasses(), LinkageSpec::Cforall, nullptr, expr->result->clone(), new SingleInit( expr->clone() ) );
323 // if expression type is a reference, don't need to construct anything, a simple initializer is sufficient.
324 if ( ! dynamic_cast< ReferenceType * >( expr->result ) ) {
325 ConstructorInit * ctorInit = InitTweak::genCtorInit( ret );
326 ret->init = ctorInit;
327 ResolvExpr::resolveCtorInit( ctorInit, spotter.currentFinder.get_indexer() ); // resolve ctor/dtors for the new object
328 PassVisitor<EnvRemover> rm; // remove environments from subexpressions of StmtExprs
329 rm.pass.compositeEnv = &compositeEnv;
330 ctorInit->accept( rm );
331 }
332 PRINT( std::cerr << "new object: " << ret << std::endl; )
333 return ret;
334 }
335
336 void TupleAssignSpotter_old::MassAssignMatcher::match( std::list< Expression * > &out ) {
337 static UniqueName lhsNamer( "__massassign_L" );
338 static UniqueName rhsNamer( "__massassign_R" );
339 // empty tuple case falls into this matcher, hence the second part of the assert
340 assert( (! lhs.empty() && rhs.size() <= 1) || (lhs.empty() && rhs.empty()) );
341
342 // xxx - may need to split this up into multiple declarations, because potential conversion to references
343 // probably should not reference local variable - see MultipleAssignMatcher::match
344 ObjectDecl * rtmp = rhs.size() == 1 ? newObject( rhsNamer, rhs.front().expr ) : nullptr;
345 for ( ResolvExpr::Alternative & lhsAlt : lhs ) {
346 // create a temporary object for each value in the lhs and create a call involving the rhs
347 ObjectDecl * ltmp = newObject( lhsNamer, lhsAlt.expr );
348 out.push_back( createFunc( spotter.fname, ltmp, rtmp ) );
349 tmpDecls.push_back( ltmp );
350 }
351 if ( rtmp ) tmpDecls.push_back( rtmp );
352 }
353
354 void TupleAssignSpotter_old::MultipleAssignMatcher::match( std::list< Expression * > &out ) {
355 static UniqueName lhsNamer( "__multassign_L" );
356 static UniqueName rhsNamer( "__multassign_R" );
357
358 if ( lhs.size() == rhs.size() ) {
359 // produce a new temporary object for each value in the lhs and rhs and pairwise create the calls
360 std::list< ObjectDecl * > ltmp;
361 std::list< ObjectDecl * > rtmp;
362 for ( auto p : group_iterate( lhs, rhs ) ) {
363 ResolvExpr::Alternative & lhsAlt = std::get<0>(p);
364 ResolvExpr::Alternative & rhsAlt = std::get<1>(p);
365 // convert RHS to LHS type minus one reference -- important for the case where LHS is && and RHS is lvalue, etc.
366 ReferenceType * lhsType = strict_dynamic_cast<ReferenceType *>( lhsAlt.expr->result );
367 rhsAlt.expr = new CastExpr( rhsAlt.expr, lhsType->base->clone() );
368 ObjectDecl * lobj = newObject( lhsNamer, lhsAlt.expr );
369 ObjectDecl * robj = newObject( rhsNamer, rhsAlt.expr );
370 out.push_back( createFunc(spotter.fname, lobj, robj) );
371 ltmp.push_back( lobj );
372 rtmp.push_back( robj );
373
374 // resolve the cast expression so that rhsAlt return type is bound by the cast type as needed, and transfer the resulting environment
375 ResolvExpr::AlternativeFinder finder{ spotter.currentFinder.get_indexer(), compositeEnv };
376 finder.findWithAdjustment( rhsAlt.expr );
377 assert( finder.get_alternatives().size() == 1 );
378 compositeEnv = std::move( finder.get_alternatives().front().env );
379 }
380 tmpDecls.splice( tmpDecls.end(), ltmp );
381 tmpDecls.splice( tmpDecls.end(), rtmp );
382 }
383 }
384
385namespace {
386 /// true if `expr` is of tuple type
387 bool isTuple( const ast::Expr * expr ) {
388 if ( ! expr ) return false;
389 assert( expr->result );
390 return dynamic_cast< const ast::TupleType * >( expr->result->stripReferences() );
391 }
392
393 /// true if `expr` is of tuple type or a reference to one
394 bool refToTuple( const ast::Expr * expr ) {
395 assert( expr->result );
396 // check for function returning tuple of reference types
397 if ( auto castExpr = dynamic_cast< const ast::CastExpr * >( expr ) ) {
398 return refToTuple( castExpr->arg );
399 } else {
400 return isTuple( expr );
401 }
402 }
403
404 /// Dispatcher for tuple (multiple and mass) assignment operations
405 class TupleAssignSpotter_new final {
406 /// Actually finds tuple assignment operations, by subclass
407 struct Matcher {
408 ResolvExpr::CandidateList lhs, rhs;
409 TupleAssignSpotter_new & spotter;
410 CodeLocation location;
411 ResolvExpr::Cost baseCost;
412 std::vector< ast::ptr< ast::ObjectDecl > > tmpDecls;
413 ast::TypeEnvironment env;
414 ast::OpenVarSet open;
415 ast::AssertionSet need;
416
417 void combineState( const ResolvExpr::Candidate & cand ) {
418 env.simpleCombine( cand.env );
419 ast::mergeOpenVars( open, cand.open );
420 need.insert( cand.need.begin(), cand.need.end() );
421 }
422
423 Matcher(
424 TupleAssignSpotter_new & s, const CodeLocation & loc,
425 const ResolvExpr::CandidateList & l, const ResolvExpr::CandidateList & r )
426 : lhs( l ), rhs( r ), spotter( s ), location( loc ),
427 baseCost( ResolvExpr::sumCost( lhs ) + ResolvExpr::sumCost( rhs ) ), tmpDecls(),
428 env(), open(), need() {
429 for ( auto & cand : lhs ) combineState( *cand );
430 for ( auto & cand : rhs ) combineState( *cand );
431 }
432 virtual ~Matcher() = default;
433
434 virtual std::vector< ast::ptr< ast::Expr > > match() = 0;
435
436 /// removes environments from subexpressions within statement expressions, which could
437 /// throw off later passes like those in Box which rely on PolyMutator, and adds the
438 /// bindings to the env
439 struct EnvRemover {
440 /// environment to hoist ExprStmt environments to
441 ast::TypeEnvironment & tenv;
442
443 EnvRemover( ast::TypeEnvironment & e ) : tenv( e ) {}
444
445 const ast::ExprStmt * previsit( const ast::ExprStmt * stmt ) {
446 if ( stmt->expr->env ) {
447 tenv.add( *stmt->expr->env );
448 ast::ExprStmt * mut = mutate( stmt );
449 mut->expr.get_and_mutate()->env = nullptr;
450 return mut;
451 }
452 return stmt;
453 }
454 };
455
456 ast::ObjectDecl * newObject( UniqueName & namer, const ast::Expr * expr ) {
457 assert( expr->result && ! expr->result->isVoid() );
458
459 ast::ObjectDecl * ret = new ast::ObjectDecl{
460 location, namer.newName(), expr->result, new ast::SingleInit{ location, expr },
461 ast::Storage::Classes{}, ast::Linkage::Cforall };
462
463 // if expression type is a reference, just need an initializer, otherwise construct
464 if ( ! expr->result.as< ast::ReferenceType >() ) {
465 // resolve ctor/dtor for the new object
466 ast::ptr< ast::Init > ctorInit = ResolvExpr::resolveCtorInit(
467 InitTweak::genCtorInit( location, ret ), spotter.crntFinder.context );
468 // remove environments from subexpressions of stmtExpr
469 ast::Pass< EnvRemover > rm{ env };
470 ret->init = ctorInit->accept( rm );
471 }
472
473 PRINT( std::cerr << "new object: " << ret << std::endl; )
474 return ret;
475 }
476
477 ast::UntypedExpr * createFunc(
478 const std::string & fname, const ast::ObjectDecl * left,
479 const ast::ObjectDecl * right
480 ) {
481 assert( left );
482 std::vector< ast::ptr< ast::Expr > > args;
483 args.emplace_back( new ast::VariableExpr{ location, left } );
484 if ( right ) { args.emplace_back( new ast::VariableExpr{ location, right } ); }
485
486 if ( left->type->referenceDepth() > 1 && CodeGen::isConstructor( fname ) ) {
487 args.front() = new ast::AddressExpr{ location, args.front() };
488 if ( right ) { args.back() = new ast::AddressExpr{ location, args.back() }; }
489 return new ast::UntypedExpr{
490 location, new ast::NameExpr{ location, "?=?" }, std::move(args) };
491 } else {
492 return new ast::UntypedExpr{
493 location, new ast::NameExpr{ location, fname }, std::move(args) };
494 }
495 }
496 };
497
498 /// Finds mass-assignment operations
499 struct MassAssignMatcher final : public Matcher {
500 MassAssignMatcher(
501 TupleAssignSpotter_new & s, const CodeLocation & loc,
502 const ResolvExpr::CandidateList & l, const ResolvExpr::CandidateList & r )
503 : Matcher( s, loc, l, r ) {}
504
505 std::vector< ast::ptr< ast::Expr > > match() override {
506 static UniqueName lhsNamer( "__massassign_L" );
507 static UniqueName rhsNamer( "__massassign_R" );
508 // empty tuple case falls into this matcher
509 assert( lhs.empty() ? rhs.empty() : rhs.size() <= 1 );
510
511 ast::ptr< ast::ObjectDecl > rtmp =
512 rhs.size() == 1 ? newObject( rhsNamer, rhs.front()->expr ) : nullptr;
513
514 std::vector< ast::ptr< ast::Expr > > out;
515 for ( ResolvExpr::CandidateRef & lhsCand : lhs ) {
516 // create a temporary object for each value in the LHS and create a call
517 // involving the RHS
518 ast::ptr< ast::ObjectDecl > ltmp = newObject( lhsNamer, lhsCand->expr );
519 out.emplace_back( createFunc( spotter.fname, ltmp, rtmp ) );
520 tmpDecls.emplace_back( std::move( ltmp ) );
521 }
522 if ( rtmp ) tmpDecls.emplace_back( std::move( rtmp ) );
523
524 return out;
525 }
526 };
527
528 /// Finds multiple-assignment operations
529 struct MultipleAssignMatcher final : public Matcher {
530 MultipleAssignMatcher(
531 TupleAssignSpotter_new & s, const CodeLocation & loc,
532 const ResolvExpr::CandidateList & l, const ResolvExpr::CandidateList & r )
533 : Matcher( s, loc, l, r ) {}
534
535 std::vector< ast::ptr< ast::Expr > > match() override {
536 static UniqueName lhsNamer( "__multassign_L" );
537 static UniqueName rhsNamer( "__multassign_R" );
538
539 if ( lhs.size() != rhs.size() ) return {};
540
541 // produce a new temporary object for each value in the LHS and RHS and pairwise
542 // create the calls
543 std::vector< ast::ptr< ast::ObjectDecl > > ltmp, rtmp;
544
545 std::vector< ast::ptr< ast::Expr > > out;
546 for ( unsigned i = 0; i < lhs.size(); ++i ) {
547 ResolvExpr::CandidateRef & lhsCand = lhs[i];
548 ResolvExpr::CandidateRef & rhsCand = rhs[i];
549
550 // convert RHS to LHS type minus one reference -- important for case where LHS
551 // is && and RHS is lvalue
552 auto lhsType = lhsCand->expr->result.strict_as< ast::ReferenceType >();
553 rhsCand->expr = new ast::CastExpr{ rhsCand->expr, lhsType->base };
554 ast::ptr< ast::ObjectDecl > lobj = newObject( lhsNamer, lhsCand->expr );
555 ast::ptr< ast::ObjectDecl > robj = newObject( rhsNamer, rhsCand->expr );
556 out.emplace_back( createFunc( spotter.fname, lobj, robj ) );
557 ltmp.emplace_back( std::move( lobj ) );
558 rtmp.emplace_back( std::move( robj ) );
559
560 // resolve the cast expression so that rhsCand return type is bound by the cast
561 // type as needed, and transfer the resulting environment
562 ResolvExpr::CandidateFinder finder( spotter.crntFinder.context, env );
563 finder.find( rhsCand->expr, ResolvExpr::ResolvMode::withAdjustment() );
564 assert( finder.candidates.size() == 1 );
565 env = std::move( finder.candidates.front()->env );
566 }
567
568 splice( tmpDecls, ltmp );
569 splice( tmpDecls, rtmp );
570
571 return out;
572 }
573 };
574
575 ResolvExpr::CandidateFinder & crntFinder;
576 std::string fname;
577 std::unique_ptr< Matcher > matcher;
578
579 public:
580 TupleAssignSpotter_new( ResolvExpr::CandidateFinder & f )
581 : crntFinder( f ), fname(), matcher() {}
582
583 // find left- and right-hand-sides for mass or multiple assignment
584 void spot(
585 const ast::UntypedExpr * expr, std::vector< ResolvExpr::CandidateFinder > & args
586 ) {
587 if ( auto op = expr->func.as< ast::NameExpr >() ) {
588 // skip non-assignment functions
589 if ( ! CodeGen::isCtorDtorAssign( op->name ) ) return;
590 fname = op->name;
591
592 // handled by CandidateFinder if applicable (both odd cases)
593 if ( args.empty() || ( args.size() == 1 && CodeGen::isAssignment( fname ) ) ) {
594 return;
595 }
596
597 // look over all possible left-hand-side
598 for ( ResolvExpr::CandidateRef & lhsCand : args[0] ) {
599 // skip non-tuple LHS
600 if ( ! refToTuple( lhsCand->expr ) ) continue;
601
602 // explode is aware of casts - ensure every LHS is sent into explode with a
603 // reference cast
604 if ( ! lhsCand->expr.as< ast::CastExpr >() ) {
605 lhsCand->expr = new ast::CastExpr{
606 lhsCand->expr, new ast::ReferenceType{ lhsCand->expr->result } };
607 }
608
609 // explode the LHS so that each field of a tuple-valued expr is assigned
610 ResolvExpr::CandidateList lhs;
611 explode( *lhsCand, crntFinder.context.symtab, back_inserter(lhs), true );
612 for ( ResolvExpr::CandidateRef & cand : lhs ) {
613 // each LHS value must be a reference - some come in with a cast, if not
614 // just cast to reference here
615 if ( ! cand->expr->result.as< ast::ReferenceType >() ) {
616 cand->expr = new ast::CastExpr{
617 cand->expr, new ast::ReferenceType{ cand->expr->result } };
618 }
619 }
620
621 if ( args.size() == 1 ) {
622 // mass default-initialization/destruction
623 ResolvExpr::CandidateList rhs{};
624 matcher.reset( new MassAssignMatcher{ *this, expr->location, lhs, rhs } );
625 match();
626 } else if ( args.size() == 2 ) {
627 for ( const ResolvExpr::CandidateRef & rhsCand : args[1] ) {
628 ResolvExpr::CandidateList rhs;
629 if ( isTuple( rhsCand->expr ) ) {
630 // multiple assignment
631 explode( *rhsCand, crntFinder.context.symtab, back_inserter(rhs), true );
632 matcher.reset(
633 new MultipleAssignMatcher{ *this, expr->location, lhs, rhs } );
634 } else {
635 // mass assignment
636 rhs.emplace_back( rhsCand );
637 matcher.reset(
638 new MassAssignMatcher{ *this, expr->location, lhs, rhs } );
639 }
640 match();
641 }
642 } else {
643 // expand all possible RHS possibilities
644 std::vector< ResolvExpr::CandidateList > rhsCands;
645 combos(
646 std::next( args.begin(), 1 ), args.end(), back_inserter( rhsCands ) );
647 for ( const ResolvExpr::CandidateList & rhsCand : rhsCands ) {
648 // multiple assignment
649 ResolvExpr::CandidateList rhs;
650 explode( rhsCand, crntFinder.context.symtab, back_inserter(rhs), true );
651 matcher.reset(
652 new MultipleAssignMatcher{ *this, expr->location, lhs, rhs } );
653 match();
654 }
655 }
656 }
657 }
658 }
659
660 void match() {
661 assert( matcher );
662
663 std::vector< ast::ptr< ast::Expr > > newAssigns = matcher->match();
664
665 if ( ! ( matcher->lhs.empty() && matcher->rhs.empty() ) ) {
666 // if both LHS and RHS are empty than this is the empty tuple case, wherein it's
667 // okay for newAssigns to be empty. Otherwise, return early so that no new
668 // candidates are generated
669 if ( newAssigns.empty() ) return;
670 }
671
672 ResolvExpr::CandidateList crnt;
673 // now resolve new assignments
674 for ( const ast::Expr * expr : newAssigns ) {
675 PRINT(
676 std::cerr << "== resolving tuple assign ==" << std::endl;
677 std::cerr << expr << std::endl;
678 )
679
680 ResolvExpr::CandidateFinder finder( crntFinder.context, matcher->env );
681
682 try {
683 finder.find( expr, ResolvExpr::ResolvMode::withAdjustment() );
684 } catch (...) {
685 // no match is not failure, just that this tuple assignment is invalid
686 return;
687 }
688
689 ResolvExpr::CandidateList & cands = finder.candidates;
690 assert( cands.size() == 1 );
691 assert( cands.front()->expr );
692 crnt.emplace_back( std::move( cands.front() ) );
693 }
694
695 // extract expressions from the assignment candidates to produce a list of assignments
696 // that together form a sigle candidate
697 std::vector< ast::ptr< ast::Expr > > solved;
698 for ( ResolvExpr::CandidateRef & cand : crnt ) {
699 solved.emplace_back( cand->expr );
700 matcher->combineState( *cand );
701 }
702
703 crntFinder.candidates.emplace_back( std::make_shared< ResolvExpr::Candidate >(
704 new ast::TupleAssignExpr{
705 matcher->location, std::move( solved ), std::move( matcher->tmpDecls ) },
706 std::move( matcher->env ), std::move( matcher->open ), std::move( matcher->need ),
707 ResolvExpr::sumCost( crnt ) + matcher->baseCost ) );
708 }
709 };
710} // anonymous namespace
711
712void handleTupleAssignment(
713 ResolvExpr::CandidateFinder & finder, const ast::UntypedExpr * assign,
714 std::vector< ResolvExpr::CandidateFinder > & args
715) {
716 TupleAssignSpotter_new spotter{ finder };
717 spotter.spot( assign, args );
718}
719
720} // namespace Tuples
721
722// Local Variables: //
723// tab-width: 4 //
724// mode: c++ //
725// compile-command: "make install" //
726// End: //
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