source: src/GenPoly/LvalueNew.cpp@ 8fd1b7c

ADT ast-experimental
Last change on this file since 8fd1b7c was 9feb34b, checked in by Andrew Beach <ajbeach@…>, 2 years ago

Moved toString and toCString to a new header. Updated includes. cassert was somehow getting instances of toString before but that stopped working so I embedded the new smaller include.

  • Property mode set to 100644
File size: 22.8 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// LvalueNew.cpp -- Clean up lvalues and remove references.
8//
9// Author : Andrew Beach
10// Created On : Thu Sep 15 14:08:00 2022
11// Last Modified By : Andrew Beach
12// Last Modified On : Wed Oct 6 9:59:00 2022
13// Update Count : 0
14//
15
16#include "Lvalue.h"
17
18#include <set>
19#include <iostream>
20
21#include "AST/Copy.hpp" // for deepCopy
22#include "AST/Expr.hpp"
23#include "AST/Inspect.hpp"
24#include "AST/LinkageSpec.hpp" // for Linkage
25#include "AST/Pass.hpp"
26#include "Common/SemanticError.h" // for SemanticWarning
27#include "Common/ToString.hpp" // for toCString
28#include "Common/UniqueName.h" // for UniqueName
29#include "GenPoly/GenPoly.h" // for genFunctionType
30#include "ResolvExpr/typeops.h" // for typesCompatible
31#include "ResolvExpr/Unify.h" // for unify
32
33#if 0
34#define PRINT(x) x
35#else
36#define PRINT(x)
37#endif
38
39namespace GenPoly {
40
41namespace {
42
43/// Intrinsic functions that return references now instead return lvalues.
44struct FixIntrinsicResults final : public ast::WithGuards {
45 enum {
46 NoSkip,
47 Skip,
48 SkipInProgress,
49 } skip = NoSkip;
50
51 void previsit( ast::AsmExpr const * ) {
52 GuardValue( skip ) = Skip;
53 }
54 void previsit( ast::ApplicationExpr const * ) {
55 GuardValue( skip ) = (skip == Skip) ? SkipInProgress : NoSkip;
56 }
57
58 ast::Expr const * postvisit( ast::ApplicationExpr const * expr );
59 void previsit( ast::FunctionDecl const * decl );
60 bool inIntrinsic = false;
61};
62
63/// Add de-references around address-of operations on reference types.
64struct AddressRef final :
65 public ast::WithConstTranslationUnit,
66 public ast::WithGuards,
67 public ast::WithShortCircuiting,
68 public ast::WithVisitorRef<AddressRef> {
69 void previsit( ast::AddressExpr const * expr );
70 ast::Expr const * postvisit( ast::AddressExpr const * expr );
71 void previsit( ast::Expr const * expr );
72 ast::ApplicationExpr const * previsit( ast::ApplicationExpr const * expr );
73 void previsit( ast::SingleInit const * init );
74
75 void handleNonAddr( ast::Expr const * expr );
76
77 bool first = true;
78 bool current = false;
79 bool addCast = false;
80 int refDepth = 0;
81};
82
83/// Handles casts between references and pointers,
84/// creating temporaries for the conversion.
85struct ReferenceConversions final :
86 public ast::WithConstTranslationUnit,
87 public ast::WithGuards, public ast::WithStmtsToAdd<> {
88 ast::Expr const * postvisit( ast::CastExpr const * expr );
89 ast::Expr const * postvisit( ast::AddressExpr const * expr );
90};
91
92/// Intrinsic functions that take reference parameters don't actually do.
93/// Their reference arguments must be implicity dereferenced.
94/// TODO Also appears to contain redundent code with AddressRef
95struct FixIntrinsicArgs final :
96 public ast::WithConstTranslationUnit {
97 ast::Expr const * postvisit( ast::ApplicationExpr const * expr );
98};
99
100/// Removes redundant &* / *& patterns that may be generated.
101struct CollapseAddressDeref final {
102 ast::Expr const * postvisit( ast::AddressExpr const * expr );
103 ast::Expr const * postvisit( ast::ApplicationExpr const * expr );
104};
105
106/// GCC-like Generalized Lvalues (which have since been removed from GCC).
107/// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
108/// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
109struct GeneralizedLvalue final :
110 public ast::WithVisitorRef<GeneralizedLvalue> {
111 ast::Expr const * postvisit( ast::AddressExpr const * expr );
112 ast::Expr const * postvisit( ast::MemberExpr const * expr );
113
114 template<typename Node, typename Func>
115 ast::Expr const * applyTransformation(
116 Node const * expr, ast::ptr<ast::Expr> Node::*field, Func mkExpr );
117};
118
119/// Replace all reference types with pointer types.
120struct ReferenceTypeElimination final {
121 ast::Type const * postvisit( ast::ReferenceType const * type );
122};
123
124/// True for intrinsic function calls that return an lvalue in C.
125bool isIntrinsicReference( ast::Expr const * expr ) {
126 // The known intrinsic-reference prelude functions.
127 static std::set<std::string> const lvalueFunctions = { "*?", "?[?]" };
128 if ( auto untyped = dynamic_cast<ast::UntypedExpr const *>( expr ) ) {
129 std::string fname = ast::getFunctionName( untyped );
130 return lvalueFunctions.count( fname );
131 } else if ( auto app = dynamic_cast<ast::ApplicationExpr const *>( expr ) ) {
132 if ( auto func = ast::getFunction( app ) ) {
133 return func->linkage == ast::Linkage::Intrinsic
134 && lvalueFunctions.count( func->name );
135 }
136 }
137 return false;
138}
139
140// A maybe typed variant of the createDeref function (only UntypedExpr).
141ast::Expr * mkDeref(
142 ast::TranslationGlobal const & global, ast::Expr const * arg ) {
143 if ( global.dereference ) {
144 // Note: Reference depth can be arbitrarily deep here,
145 // so peel off the outermost pointer/reference, not just
146 // pointer because they are effecitvely equivalent in this pass
147 ast::VariableExpr * deref = new ast::VariableExpr(
148 arg->location, global.dereference );
149 deref->result = new ast::PointerType( deref->result );
150 ast::Type const * base = ast::getPointerBase( arg->result );
151 assertf( base, "expected pointer type in dereference (type was %s)", toString( arg->result ).c_str() );
152 ast::ApplicationExpr * ret =
153 new ast::ApplicationExpr( arg->location, deref, { arg } );
154 ret->result = ast::deepCopy( base );
155 return ret;
156 } else {
157 return ast::UntypedExpr::createDeref( arg->location, arg );
158 }
159}
160
161ast::Expr const * FixIntrinsicResults::postvisit(
162 ast::ApplicationExpr const * expr ) {
163 if ( skip == SkipInProgress || !isIntrinsicReference( expr ) ) {
164 return expr;
165 }
166 // Eliminate reference types from intrinsic applications
167 // now they return lvalues.
168 ast::ptr<ast::ReferenceType> result =
169 expr->result.strict_as<ast::ReferenceType>();
170 expr = ast::mutate_field( expr, &ast::ApplicationExpr::result,
171 ast::deepCopy( result->base ) );
172 if ( inIntrinsic ) {
173 return expr;
174 }
175 // When not in an intrinsic function, add a cast to don't add cast when
176 // in an intrinsic function, since they already have the cast.
177 auto * ret = new ast::CastExpr( expr->location, expr, result.get() );
178 ret->env = expr->env;
179 return ret;
180}
181
182void FixIntrinsicResults::previsit( ast::FunctionDecl const * decl ) {
183 GuardValue( inIntrinsic ) = decl->linkage == ast::Linkage::Intrinsic;
184}
185
186void AddressRef::previsit( ast::AddressExpr const * ) {
187 // Is this the first address-of in the chain?
188 GuardValue( current ) = first;
189 // Later references will not be for next address-of to be first in chain.
190 GuardValue( first ) = false;
191 // If is the outermost address-of in a chain:
192 if ( current ) {
193 // Set depth to 0 so that postvisit can
194 // find the innermost address-of easily.
195 GuardValue( refDepth ) = 0;
196 }
197}
198
199ast::Expr const * AddressRef::postvisit( ast::AddressExpr const * expr ) {
200 PRINT( std::cerr << "addr ref at " << expr << std::endl; )
201 if ( 0 == refDepth ) {
202 PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
203 // Is this the innermost address-of in a chain? record depth D.
204 if ( isIntrinsicReference( expr->arg ) ) {
205 assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( expr->arg ) );
206 } else {
207 // try to avoid ?[?]
208 // TODO is this condition still necessary? intrinsicReferences
209 // should have a cast around them at this point, so I don't think
210 // this condition ever fires.
211 refDepth = expr->arg->result->referenceDepth();
212 PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
213 }
214 }
215 if ( current ) {
216 PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
217 ast::Expr const * ret = expr;
218 while ( refDepth ) {
219 // Add one dereference for each address-of in the chain.
220 ret = mkDeref( transUnit().global, ret );
221 --refDepth;
222 }
223
224 // if addrExpr depth is 0, then the result is a pointer because the
225 // arg was depth 1 and not lvalue. This means the dereference result
226 // is not a reference, is lvalue, and one less pointer depth than the
227 // addrExpr. Thus the cast is meaningless.
228 // TODO: One thing to double check is whether it is possible for the
229 // types to differ outside of the single pointer level (i.e. can the
230 // base type of addrExpr differ from the type of addrExpr-arg?). If
231 // so then the cast might need to be added, conditional on a more
232 // sophisticated check.
233 if ( addCast && 0 != expr->result->referenceDepth() ) {
234 PRINT( std::cerr << "adding cast to " << expr->result << std::endl; )
235 return new ast::CastExpr( expr->location,
236 ret, ast::deepCopy( expr->result ) );
237 }
238 return ret;
239 }
240 PRINT( std::cerr << "not current..." << std::endl; )
241 return expr;
242}
243
244void AddressRef::previsit( ast::Expr const * expr ) {
245 handleNonAddr( expr );
246 GuardValue( addCast ) = false;
247}
248
249// So we want to skip traversing to the head?
250ast::ApplicationExpr const * AddressRef::previsit(
251 ast::ApplicationExpr const * expr ) {
252 visit_children = false;
253 GuardValue( addCast );
254 handleNonAddr( expr );
255 auto mutExpr = ast::mutate( expr );
256 for ( ast::ptr<ast::Expr> & arg : mutExpr->args ) {
257 addCast = true;
258 arg = arg->accept( *visitor );
259 }
260 return mutExpr;
261}
262
263void AddressRef::previsit( ast::SingleInit const * ) {
264 // Each initialization context with address-of requires a cast.
265 GuardValue( addCast ) = true;
266}
267
268// idea: &&&E: get outer &, inner &
269// at inner &, record depth D of reference type of argument of &.
270// at auter &, add D derefs.
271void AddressRef::handleNonAddr( ast::Expr const * ) {
272 // non-address-of: reset status variables:
273 // * current expr is NOT the first address-of expr in an address-of chain.
274 // * next seen address-of expr IS the first in the chain.
275 GuardValue( current ) = false;
276 GuardValue( first ) = true;
277}
278
279ast::Expr const * ReferenceConversions::postvisit(
280 ast::CastExpr const * expr ) {
281 // TODO: Is it possible to convert directly between reference types with
282 // a different base. e.g.
283 // int x;
284 // (double&)x;
285 // At the moment, I (who?) am working off of the assumption that this is
286 // illegal, thus the cast becomes redundant after this pass, so trash the
287 // cast altogether. If that changes, care must be taken to insert the
288 // correct pointer casts in the right places.
289
290 // Note: reference depth difference is the determining factor in what
291 // code is run, rather than whether something is reference type or not,
292 // since conversion still needs to occur when both types are references
293 // that differ in depth.
294 ast::Type const * dstType = expr->result.get();
295 ast::Type const * srcType = expr->arg->result.get();
296 assertf( dstType, "Cast to no type in: %s", toCString( expr ) );
297 assertf( srcType, "Cast from no type in: %s", toCString( expr ) );
298 int dstDepth = dstType->referenceDepth();
299 int srcDepth = srcType->referenceDepth();
300 int diff = dstDepth - srcDepth;
301
302 if ( 0 < diff && !expr->arg->get_lvalue() ) {
303 // rvalue to reference conversion -- introduce temporary
304 // know that reference depth of cast argument is 0
305 // (int &&&)3;
306 // becomes
307 // int __ref_tmp_0 = 3;
308 // int & __ref_tmp_1 = &__ref_tmp_0;
309 // int && __ref_tmp_2 = &__ref_tmp_1;
310 // &__ref_tmp_2;
311 // The last & comes from the remaining reference conversion code.
312 SemanticWarning( expr->arg->location,
313 Warning::RvalueToReferenceConversion, toCString( expr->arg ) );
314
315 static UniqueName tmpNamer( "__ref_tmp_" );
316 ast::ObjectDecl * tmp = new ast::ObjectDecl( expr->arg->location,
317 tmpNamer.newName(),
318 ast::deepCopy( expr->arg->result ),
319 new ast::SingleInit( expr->arg->location, expr->arg ) );
320 PRINT( std::cerr << "make tmp: " << tmp << std::endl; )
321 stmtsToAddBefore.push_back( new ast::DeclStmt( tmp->location, tmp ) );
322 for ( int i = 0 ; i < dstDepth - 1 ; ++i ) {
323 ast::ObjectDecl * newTmp = new ast::ObjectDecl( tmp->location,
324 tmpNamer.newName(),
325 new ast::ReferenceType( ast::deepCopy( tmp->type ) ),
326 new ast::SingleInit( tmp->location,
327 new ast::AddressExpr( tmp->location,
328 new ast::VariableExpr( tmp->location, tmp ) ) ) );
329 PRINT( std::cerr << "make tmp: " << i << ": " << newTmp << std::endl; )
330 stmtsToAddBefore.push_back(
331 new ast::DeclStmt( newTmp->location, newTmp ) );
332 tmp = newTmp;
333 }
334 // Update diff so that remaining code works out correctly.
335 expr = ast::mutate_field( expr, &ast::CastExpr::arg,
336 new ast::VariableExpr( tmp->location, tmp ) );
337 PRINT( std::cerr << "update cast to: " << expr << std::endl; )
338 srcType = expr->arg->result;
339 srcDepth = srcType->referenceDepth();
340 diff = dstDepth - srcDepth;
341 assert( 1 == diff );
342 }
343
344 // Handle conversion between different depths.
345 PRINT(
346 if ( dstDepth || srcDepth ) {
347 std::cerr << "dstType: " << dstType << " / srcType: " << srcType << '\n';
348 std::cerr << "depth: " << dstDepth << " / " << srcDepth << std::endl;
349 }
350 )
351 // Conversion to type with more depth/more references.
352 // Add address-of for each level of difference.
353 if ( 0 < diff ) {
354 ast::Expr * ret = ast::mutate( expr->arg.get() );
355 for ( int i = 0 ; i < diff ; ++i ) {
356 ret = new ast::AddressExpr( ret->location, ret );
357 }
358 if ( expr->arg->get_lvalue() &&
359 !ResolvExpr::typesCompatible(
360 srcType,
361 strict_dynamic_cast<ast::ReferenceType const *>( dstType )->base,
362 ast::SymbolTable() ) ) {
363 // Must keep cast if cast-to type is different from the actual type.
364 return ast::mutate_field( expr, &ast::CastExpr::arg, ret );
365 }
366 ret->env = expr->env;
367 ret->result = expr->result;
368 return ret;
369 // Conversion to type with less depth/fewer references.
370 // Add dereferences for each level of difference.
371 } else if ( diff < 0 ) {
372 ast::Expr * ret = ast::mutate( expr->arg.get() );
373 for ( int i = 0 ; i < -diff ; ++i ) {
374 ret = mkDeref( transUnit().global, ret );
375 }
376 // Must keep cast if types are different.
377 if ( !ResolvExpr::typesCompatibleIgnoreQualifiers(
378 dstType->stripReferences(),
379 srcType->stripReferences(),
380 ast::SymbolTable() ) ) {
381 return ast::mutate_field( expr, &ast::CastExpr::arg, ret );
382 }
383 ret->env = expr->env;
384 ret->result = expr->result;
385 // The result must be an lvalue.
386 assert( ret->get_lvalue() );
387 return ret;
388 // Conversion with the same depth.
389 } else {
390 assert( 0 == diff );
391 // Remove useless generated casts.
392 if ( expr->isGenerated &&
393 ResolvExpr::typesCompatible(
394 expr->result,
395 expr->arg->result, ast::SymbolTable() ) ) {
396 PRINT(
397 std::cerr << "types are compatible, removing cast: " << expr << '\n';
398 std::cerr << "-- " << expr->result << '\n';
399 std::cerr << "-- " << expr->arg->result << std::endl;
400 )
401 return ast::mutate_field( expr->arg.get(),
402 &ast::Expr::env, expr->env.get() );
403 }
404 return expr;
405 }
406}
407
408ast::Expr const * ReferenceConversions::postvisit(
409 ast::AddressExpr const * expr ) {
410 // Inner expression may have been lvalue to reference conversion, which
411 // becomes an address expression. In this case, remove the outer address
412 // expression and return the argument.
413 // TODO: It's possible that this might catch too much and require a more
414 // sophisticated check. TODO What check are we talking about here?
415 return expr;
416}
417
418ast::Expr const * FixIntrinsicArgs::postvisit(
419 ast::ApplicationExpr const * expr ) {
420 // Intrinsic functions don't really take reference-typed parameters,
421 // so they require an implicit dereference on their arguments.
422 auto function = ast::getFunction( expr );
423 if ( function == nullptr ) {
424 return expr;
425 }
426
427 ast::FunctionType const * ftype = GenPoly::getFunctionType( function->get_type() );
428 assertf( ftype, "Function declaration does not have function type." );
429 // Can be of different lengths only when function is variadic.
430 assertf( ftype->params.size() == expr->args.size() || ftype->isVarArgs,
431 "ApplicationExpr args do not match formal parameter type." );
432 assertf( ftype->params.size() <= expr->args.size(),
433 "Cannot have more parameters than arguments." );
434
435 unsigned int i = 0;
436 unsigned int const end = ftype->params.size();
437
438 // This is used to make sure we get a zip on shortests.
439 if ( end == i ) return expr;
440
441 // This mutate could be redundent, but it is simpler this way.
442 auto mutExpr = ast::mutate( expr );
443
444 for ( auto pair : unsafe_group_iterate( mutExpr->args, ftype->params ) ) {
445 ast::ptr<ast::Expr> & arg = std::get<0>( pair );
446 ast::ptr<ast::Type> const & formal = std::get<1>( pair );
447 PRINT(
448 std::cerr << "pair<0>: " << arg.get() << std::endl;
449 std::cerr << " -- " << arg->result << std::endl;
450 std::cerr << "pair<1>: " << formal << std::endl;
451 )
452 //if ( dynamic_cast<ast::ReferenceType const *>( formal.get() ) ) {
453 if ( formal.as<ast::ReferenceType>() ) {
454 PRINT( std::cerr << "===formal is reference" << std::endl; )
455 // TODO: It's likely that the second condition should be
456 // `... && ! isIntrinsicReference( arg )`, but this requires
457 // investigation.
458
459 if ( ast::Linkage::Intrinsic != function->linkage
460 && isIntrinsicReference( arg ) ) {
461 // Needed for definition of prelude functions, etc.
462 // If argument is dereference or array subscript, the result
463 // isn't REALLY a reference, but non-intrinsic functions
464 // expect a reference: take address
465
466 // TODO: OK, so this should be cut?!
467 // NODE: Previously, this condition fixed
468 // void f(int *&);
469 // int & x = ...;
470 // f(&x);
471 // But now this is taken care of by a reference cast added by
472 // AddressRef. Need to find a new example or remove this
473 // branch.
474 PRINT(
475 std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
476 )
477 arg = new ast::AddressExpr( arg->location, arg );
478 } else if ( ast::Linkage::Intrinsic == function->linkage
479 && arg->result->referenceDepth() != 0 ) {
480 // Argument is a 'real' reference, but function expects a C
481 // lvalue: Add a dereference to the reference-typed argument.
482 PRINT(
483 std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
484 )
485 ast::Type const * base = ast::getPointerBase( arg->result );
486 assertf( base, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
487 ast::PointerType * ptr = new ast::PointerType( ast::deepCopy( base ) );
488 arg = ast::mutate_field( arg.get(),
489 &ast::ApplicationExpr::result, ptr );
490 arg = mkDeref( transUnit().global, arg );
491 }
492 }
493 ++i;
494 if ( end == i ) break;
495 }
496 return mutExpr;
497}
498
499ast::Expr const * CollapseAddressDeref::postvisit(
500 ast::AddressExpr const * expr ) {
501 ast::Expr const * arg = expr->arg;
502 if ( isIntrinsicReference( arg ) ) {
503 std::string fname = ast::getFunctionName( arg );
504 if ( fname == "*?" ) {
505 ast::Expr const * arg0 = ast::getCallArg( arg, 0 );
506 ast::Expr * ret = ast::mutate( arg0 );
507 ret->env = expr->env;
508 return ret;
509 }
510 } else if ( auto cast = dynamic_cast<ast::CastExpr const *>( arg ) ) {
511 // Need to move cast to pointer type out a level since address of
512 // pointer is not valid C code (can be introduced in prior passes,
513 // e.g., InstantiateGeneric)
514 if ( ast::getPointerBase( cast->result ) ) {
515 auto mutExpr = ast::mutate( expr );
516 auto mutCast = strict_dynamic_cast<ast::CastExpr *>(
517 ast::mutate( mutExpr->arg.release() ) );
518 mutExpr->arg = mutCast->arg;
519 mutCast->arg = mutExpr;
520 mutCast->result = new ast::PointerType( mutCast->result );
521 return mutCast;
522 }
523 }
524 return expr;
525}
526
527ast::Expr const * CollapseAddressDeref::postvisit(
528 ast::ApplicationExpr const * expr ) {
529 if ( isIntrinsicReference( expr ) ) {
530 std::string fname = ast::getFunctionName( expr );
531 if ( fname == "*?" ) {
532 assert( 1 == expr->args.size() );
533 ast::Expr const * arg = ast::getCallArg( expr, 0 );
534 // xxx - this isn't right, because it can remove casts that
535 // should be there...
536 // while ( auto cast = dynamic_cast< ast::CastExpr const * >( arg ) ) {
537 // arg = cast->arg;
538 // }
539 if ( auto addr = dynamic_cast<ast::AddressExpr const *>( arg ) ) {
540 return ast::mutate_field( addr->arg.get(),
541 &ast::Expr::env, expr->env.get() );
542 }
543 }
544 }
545 return expr;
546}
547
548ast::Expr const * GeneralizedLvalue::postvisit(
549 ast::AddressExpr const * expr ) {
550 return applyTransformation( expr, &ast::AddressExpr::arg,
551 []( ast::Expr const * arg ) {
552 return new ast::AddressExpr( arg->location, arg );
553 }
554 );
555}
556
557ast::Expr const * GeneralizedLvalue::postvisit(
558 ast::MemberExpr const * expr ) {
559 return applyTransformation( expr, &ast::MemberExpr::aggregate,
560 [expr]( ast::Expr const * aggr ) {
561 return new ast::MemberExpr( aggr->location, expr->member, aggr );
562 }
563 );
564}
565
566template<typename Node, typename Func>
567ast::Expr const * GeneralizedLvalue::applyTransformation(
568 Node const * expr, ast::ptr<ast::Expr> Node::*field, Func mkExpr ) {
569 ast::ptr<ast::Expr> const & arg = expr->*field;
570 if ( auto commaArg = arg.as<ast::CommaExpr>() ) {
571 ast::Expr const * arg1 = ast::deepCopy( commaArg->arg1 );
572 ast::Expr const * arg2 = ast::deepCopy( commaArg->arg2 );
573 ast::Expr const * ret = new ast::CommaExpr(
574 commaArg->location, arg1, mkExpr( arg2 )->accept( *visitor ) );
575 return ret;
576 } else if ( auto condArg = arg.as<ast::ConditionalExpr>() ) {
577 ast::Expr const * arg1 = ast::deepCopy( condArg->arg1 );
578 ast::Expr const * arg2 = ast::deepCopy( condArg->arg2 );
579 ast::Expr const * arg3 = ast::deepCopy( condArg->arg3 );
580 ast::ConditionalExpr * ret = new ast::ConditionalExpr(
581 condArg->location, arg1, mkExpr( arg2 )->accept( *visitor ),
582 mkExpr( arg3 )->accept( *visitor ) );
583
584 // Conditional expr type may not be either of the arguments,
585 // so unify to get the result.
586 // TODO: Maybe I could create a wrapper for this.
587 ast::ptr<ast::Type> common = nullptr;
588 ast::TypeEnvironment newEnv;
589 ast::AssertionSet needAssertions, haveAssertions;
590 ast::OpenVarSet openVars;
591 ResolvExpr::unify( ret->arg2->result, ret->arg3->result, newEnv,
592 needAssertions, haveAssertions, openVars,
593 ast::SymbolTable(), common );
594 ret->result = common ? common : ast::deepCopy( ret->arg2->result );
595 return ret;
596 }
597 return expr;
598}
599
600ast::Type const * ReferenceTypeElimination::postvisit(
601 ast::ReferenceType const * type ) {
602 return new ast::PointerType( type->base, type->qualifiers );
603}
604
605} // namespace
606
607// Stored elsewhere (Lvalue2, initially false):
608extern bool referencesEliminated;
609
610void convertLvalue( ast::TranslationUnit & translationUnit ) {
611 ast::Pass<FixIntrinsicResults>::run( translationUnit );
612 ast::Pass<AddressRef>::run( translationUnit );
613 ast::Pass<ReferenceConversions>::run( translationUnit );
614 ast::Pass<FixIntrinsicArgs>::run( translationUnit );
615 ast::Pass<CollapseAddressDeref>::run( translationUnit );
616 ast::Pass<GeneralizedLvalue>::run( translationUnit );
617 // Last because other passes need reference types to work.
618 ast::Pass<ReferenceTypeElimination>::run( translationUnit );
619 // From this point forward, nothing should create reference types.
620 referencesEliminated = true;
621}
622
623ast::Expr const * generalizedLvalue( ast::Expr const * expr ) {
624 ast::Pass<GeneralizedLvalue> visitor;
625 return expr->accept( visitor );
626}
627
628} // namespace GenPoly
629
630// Local Variables: //
631// tab-width: 4 //
632// mode: c++ //
633// compile-command: "make install" //
634// End: //
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