source: src/GenPoly/Lvalue.cc@ 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: 23.5 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// Lvalue.cc --
8//
9// Author : Richard C. Bilson
10// Created On : Mon May 18 07:44:20 2015
11// Last Modified By : Andrew Beach
12// Last Modified On : Mon May 16 14:09:00 2022
13// Update Count : 8
14//
15
16#include <cassert> // for strict_dynamic_cast
17#include <string> // for string
18
19#include "Common/ToString.hpp" // for toCString
20#include "Common/UniqueName.h"
21#include "Common/PassVisitor.h"
22#include "GenPoly.h" // for isPolyType
23#include "Lvalue.h"
24
25#include "InitTweak/InitTweak.h"
26#include "ResolvExpr/TypeEnvironment.h" // for AssertionSet, OpenVarSet
27#include "ResolvExpr/Unify.h" // for unify
28#include "ResolvExpr/typeops.h"
29#include "SymTab/Indexer.h" // for Indexer
30#include "SynTree/LinkageSpec.h" // for Spec, isBuiltin, Intrinsic
31#include "SynTree/Declaration.h" // for Declaration, FunctionDecl
32#include "SynTree/Expression.h" // for Expression, ConditionalExpr
33#include "SynTree/Mutator.h" // for mutateAll, Mutator
34#include "SynTree/Statement.h" // for ReturnStmt, Statement (ptr o...
35#include "SynTree/Type.h" // for PointerType, Type, FunctionType
36#include "SynTree/Visitor.h" // for Visitor, acceptAll
37#include "Validate/FindSpecialDecls.h" // for dereferenceOperator
38
39#if 0
40#define PRINT(x) x
41#else
42#define PRINT(x)
43#endif
44
45namespace GenPoly {
46 namespace {
47 // TODO: fold this into the general createDeref function??
48 Expression * mkDeref( Expression * arg ) {
49 if ( Validate::dereferenceOperator ) {
50 // note: reference depth can be arbitrarily deep here, so peel off the outermost pointer/reference, not just pointer because they are effecitvely equivalent in this pass
51 VariableExpr * deref = new VariableExpr( Validate::dereferenceOperator );
52 deref->result = new PointerType( Type::Qualifiers(), deref->result );
53 Type * base = InitTweak::getPointerBase( arg->result );
54 assertf( base, "expected pointer type in dereference (type was %s)", toString( arg->result ).c_str() );
55 ApplicationExpr * ret = new ApplicationExpr( deref, { arg } );
56 delete ret->result;
57 ret->result = base->clone();
58 return ret;
59 } else {
60 return UntypedExpr::createDeref( arg );
61 }
62 }
63
64 struct ReferenceConversions final : public WithStmtsToAdd, public WithGuards {
65 Expression * postmutate( CastExpr * castExpr );
66 Expression * postmutate( AddressExpr * addrExpr );
67 };
68
69 /// Intrinsic functions that take reference parameters don't REALLY take reference parameters -- their reference arguments must always be implicitly dereferenced.
70 struct FixIntrinsicArgs final {
71 Expression * postmutate( ApplicationExpr * appExpr );
72 };
73
74 struct FixIntrinsicResult final : public WithGuards {
75 enum {
76 NoSkip,
77 Skip,
78 SkipInProgress
79 } skip = NoSkip;
80
81 void premutate( AsmExpr * ) { GuardValue( skip ); skip = Skip; }
82 void premutate( ApplicationExpr * ) { GuardValue( skip ); skip = (skip == Skip) ? SkipInProgress : NoSkip; }
83
84
85 Expression * postmutate( ApplicationExpr * appExpr );
86 void premutate( FunctionDecl * funcDecl );
87 bool inIntrinsic = false;
88 };
89
90 /// Replace reference types with pointer types
91 struct ReferenceTypeElimination final {
92 Type * postmutate( ReferenceType * refType );
93 };
94
95 /// GCC-like Generalized Lvalues (which have since been removed from GCC)
96 /// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
97 /// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
98 struct GeneralizedLvalue final : public WithVisitorRef<GeneralizedLvalue> {
99 Expression * postmutate( AddressExpr * addressExpr );
100 Expression * postmutate( MemberExpr * memExpr );
101
102 template<typename Func>
103 Expression * applyTransformation( Expression * expr, Expression * arg, Func mkExpr );
104 };
105
106 /// Removes redundant &*/*& pattern that this pass can generate
107 struct CollapseAddrDeref final {
108 Expression * postmutate( AddressExpr * addressExpr );
109 Expression * postmutate( ApplicationExpr * appExpr );
110 };
111
112 struct AddrRef final : public WithGuards, public WithVisitorRef<AddrRef>, public WithShortCircuiting {
113 void premutate( AddressExpr * addrExpr );
114 Expression * postmutate( AddressExpr * addrExpr );
115 void premutate( Expression * expr );
116 void premutate( ApplicationExpr * appExpr );
117 void premutate( SingleInit * init );
118
119 void handleNonAddr( Expression * );
120
121 bool first = true;
122 bool current = false;
123 int refDepth = 0;
124 bool addCast = false;
125 };
126 } // namespace
127
128 // Stored elsewhere (Lvalue2, initially false).
129 extern bool referencesEliminated;
130
131 void convertLvalue( std::list< Declaration* > & translationUnit ) {
132 PassVisitor<ReferenceConversions> refCvt;
133 PassVisitor<ReferenceTypeElimination> elim;
134 PassVisitor<GeneralizedLvalue> genLval;
135 PassVisitor<FixIntrinsicArgs> fixer;
136 PassVisitor<CollapseAddrDeref> collapser;
137 PassVisitor<AddrRef> addrRef;
138 PassVisitor<FixIntrinsicResult> intrinsicResults;
139 mutateAll( translationUnit, intrinsicResults );
140 mutateAll( translationUnit, addrRef );
141 mutateAll( translationUnit, refCvt );
142 mutateAll( translationUnit, fixer );
143 mutateAll( translationUnit, collapser );
144 mutateAll( translationUnit, genLval );
145 mutateAll( translationUnit, elim ); // last because other passes need reference types to work
146
147 // from this point forward, no other pass should create reference types.
148 referencesEliminated = true;
149 }
150
151 Expression * generalizedLvalue( Expression * expr ) {
152 PassVisitor<GeneralizedLvalue> genLval;
153 return expr->acceptMutator( genLval );
154 }
155
156 namespace {
157 // true for intrinsic function calls that return an lvalue in C
158 bool isIntrinsicReference( Expression * expr ) {
159 // known intrinsic-reference prelude functions
160 static std::set<std::string> lvalueFunctions = { "*?", "?[?]" };
161 if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
162 std::string fname = InitTweak::getFunctionName( untyped );
163 return lvalueFunctions.count(fname);
164 } else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
165 if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
166 return func->linkage == LinkageSpec::Intrinsic && lvalueFunctions.count(func->name);
167 }
168 }
169 return false;
170 }
171
172 Expression * FixIntrinsicResult::postmutate( ApplicationExpr * appExpr ) {
173 if ( skip != SkipInProgress && isIntrinsicReference( appExpr ) ) {
174 // eliminate reference types from intrinsic applications - now they return lvalues
175 ReferenceType * result = strict_dynamic_cast< ReferenceType * >( appExpr->result );
176 appExpr->result = result->base->clone();
177 if ( ! inIntrinsic ) {
178 // when not in an intrinsic function, add a cast to
179 // don't add cast when in an intrinsic function, since they already have the cast
180 Expression * ret = new CastExpr( appExpr, result );
181 std::swap( ret->env, appExpr->env );
182 return ret;
183 }
184 delete result;
185 }
186 return appExpr;
187 }
188
189 void FixIntrinsicResult::premutate( FunctionDecl * funcDecl ) {
190 GuardValue( inIntrinsic );
191 inIntrinsic = funcDecl->linkage == LinkageSpec::Intrinsic;
192 }
193
194 Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
195 // intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
196 if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
197 FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
198 assertf( ftype, "Function declaration does not have function type." );
199 // can be of differing lengths only when function is variadic
200 assertf( ftype->parameters.size() == appExpr->args.size() || ftype->isVarArgs, "ApplicationExpr args do not match formal parameter type." );
201
202
203 unsigned int i = 0;
204 const unsigned int end = ftype->parameters.size();
205
206 /// The for loop may eagerly dereference the iterators and fail on empty lists
207 if(i == end) { return appExpr; }
208 for ( auto p : unsafe_group_iterate( appExpr->args, ftype->parameters ) ) {
209 Expression *& arg = std::get<0>( p );
210 Type * formal = std::get<1>( p )->get_type();
211 PRINT(
212 std::cerr << "pair<0>: " << arg << std::endl;
213 std::cerr << " -- " << arg->result << std::endl;
214 std::cerr << "pair<1>: " << formal << std::endl;
215 )
216 if ( dynamic_cast<ReferenceType*>( formal ) ) {
217 PRINT(
218 std::cerr << "===formal is reference" << std::endl;
219 )
220 // TODO: it's likely that the second condition should be ... && ! isIntrinsicReference( arg ), but this requires investigation.
221
222 if ( function->linkage != LinkageSpec::Intrinsic && isIntrinsicReference( arg ) ) {
223 // needed for definition of prelude functions, etc.
224 // if argument is dereference or array subscript, the result isn't REALLY a reference, but non-intrinsic functions expect a reference: take address
225
226 // NOTE: previously, this condition fixed
227 // void f(int *&);
228 // int & x = ...;
229 // f(&x);
230 // But now this is taken care of by a reference cast added by AddrRef. Need to find a new
231 // example or remove this branch.
232
233 PRINT(
234 std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
235 )
236 arg = new AddressExpr( arg );
237 // } else if ( function->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getPointerBase( arg->result ) ) {
238 } else if ( function->linkage == LinkageSpec::Intrinsic && arg->result->referenceDepth() != 0 ) {
239 // argument is a 'real' reference, but function expects a C lvalue: add a dereference to the reference-typed argument
240 PRINT(
241 std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
242 )
243 Type * baseType = InitTweak::getPointerBase( arg->result );
244 assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
245 PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
246 delete arg->result;
247 arg->result = ptrType;
248 arg = mkDeref( arg );
249 // assertf( arg->result->referenceDepth() == 0, "Reference types should have been eliminated from intrinsic function calls, but weren't: %s", toCString( arg->result ) );
250 }
251 }
252 ++i;
253 if (i == end) break;
254 }
255 }
256 return appExpr;
257 }
258
259 // idea: &&&E: get outer &, inner &
260 // at inner &, record depth D of reference type of argument of &
261 // at outer &, add D derefs.
262 void AddrRef::handleNonAddr( Expression * ) {
263 // non-address-of: reset status variables:
264 // * current expr is NOT the first address-of expr in an address-of chain
265 // * next seen address-of expr IS the first in the chain.
266 GuardValue( current );
267 GuardValue( first );
268 current = false;
269 first = true;
270 }
271
272 void AddrRef::premutate( Expression * expr ) {
273 handleNonAddr( expr );
274 GuardValue( addCast );
275 addCast = false;
276 }
277
278 void AddrRef::premutate( AddressExpr * ) {
279 GuardValue( current );
280 GuardValue( first );
281 current = first; // is this the first address-of in the chain?
282 first = false; // from here out, no longer possible for next address-of to be first in chain
283 if ( current ) { // this is the outermost address-of in a chain
284 GuardValue( refDepth );
285 refDepth = 0; // set depth to 0 so that postmutate can find the innermost address-of easily
286 }
287 }
288
289 Expression * AddrRef::postmutate( AddressExpr * addrExpr ) {
290 PRINT( std::cerr << "addr ref at " << addrExpr << std::endl; )
291 if ( refDepth == 0 ) {
292 PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
293 // this is the innermost address-of in a chain, record depth D
294 if ( ! isIntrinsicReference( addrExpr->arg ) ) {
295 // try to avoid ?[?]
296 // xxx - is this condition still necessary? intrinsicReferences should have a cast around them at this point, so I don't think this condition ever fires.
297 refDepth = addrExpr->arg->result->referenceDepth();
298 PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
299 } else {
300 assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( addrExpr->arg ) );
301 }
302 }
303 if ( current ) { // this is the outermost address-of in a chain
304 PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
305 Expression * ret = addrExpr;
306 while ( refDepth ) {
307 // add one dereference for each
308 ret = mkDeref( ret );
309 refDepth--;
310 }
311
312 // if addrExpr depth is 0, then the result is a pointer because the arg was depth 1 and not lvalue.
313 // This means the dereference result is not a reference, is lvalue, and one less pointer depth than
314 // the addrExpr. Thus the cast is meaningless.
315 // TODO: One thing to double check is whether it is possible for the types to differ outside of the single
316 // pointer level (i.e. can the base type of addrExpr differ from the type of addrExpr-arg?).
317 // If so then the cast might need to be added, conditional on a more sophisticated check.
318 if ( addCast && addrExpr->result->referenceDepth() != 0 ) {
319 PRINT( std::cerr << "adding cast to " << addrExpr->result << std::endl; )
320 return new CastExpr( ret, addrExpr->result->clone() );
321 }
322 return ret;
323 }
324 PRINT( std::cerr << "not current..." << std::endl; )
325 return addrExpr;
326 }
327
328 void AddrRef::premutate( ApplicationExpr * appExpr ) {
329 visit_children = false;
330 GuardValue( addCast );
331 handleNonAddr( appExpr );
332 for ( Expression *& arg : appExpr->args ) {
333 // each argument with address-of requires a cast
334 addCast = true;
335 arg = arg->acceptMutator( *visitor );
336 }
337 }
338
339 void AddrRef::premutate( SingleInit * ) {
340 GuardValue( addCast );
341 // each initialization context with address-of requires a cast
342 addCast = true;
343 }
344
345
346 Expression * ReferenceConversions::postmutate( AddressExpr * addrExpr ) {
347 // Inner expression may have been lvalue to reference conversion, which becomes an address expression.
348 // In this case, remove the outer address expression and return the argument.
349 // TODO: It's possible that this might catch too much and require a more sophisticated check.
350 return addrExpr;
351 }
352
353 Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
354 // xxx - is it possible to convert directly between reference types with a different base? E.g.,
355 // int x;
356 // (double&)x;
357 // At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
358 // after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
359 // pointer casts in the right places.
360
361 // Note: reference depth difference is the determining factor in what code is run, rather than whether something is
362 // reference type or not, since conversion still needs to occur when both types are references that differ in depth.
363
364 Type * destType = castExpr->result;
365 Type * srcType = castExpr->arg->result;
366 assertf( destType, "Cast to no type in: %s", toCString( castExpr ) );
367 assertf( srcType, "Cast from no type in: %s", toCString( castExpr ) );
368 int depth1 = destType->referenceDepth();
369 int depth2 = srcType->referenceDepth();
370 int diff = depth1 - depth2;
371
372 if ( diff > 0 && ! castExpr->arg->get_lvalue() ) {
373 // rvalue to reference conversion -- introduce temporary
374 // know that reference depth of cast argument is 0, need to introduce n temporaries for reference depth of n, e.g.
375 // (int &&&)3;
376 // becomes
377 // int __ref_tmp_0 = 3;
378 // int & __ref_tmp_1 = _&_ref_tmp_0;
379 // int && __ref_tmp_2 = &__ref_tmp_1;
380 // &__ref_tmp_2;
381 // the last & comes from the remaining reference conversion code
382 SemanticWarning( castExpr->arg->location, Warning::RvalueToReferenceConversion, toCString( castExpr->arg ) );
383
384 static UniqueName tempNamer( "__ref_tmp_" );
385 ObjectDecl * temp = ObjectDecl::newObject( tempNamer.newName(), castExpr->arg->result->clone(), new SingleInit( castExpr->arg ) );
386 PRINT( std::cerr << "made temp: " << temp << std::endl; )
387 stmtsToAddBefore.push_back( new DeclStmt( temp ) );
388 for ( int i = 0; i < depth1-1; i++ ) { // xxx - maybe this should be diff-1? check how this works with reference type for srcType
389 ObjectDecl * newTemp = ObjectDecl::newObject( tempNamer.newName(), new ReferenceType( Type::Qualifiers(), temp->type->clone() ), new SingleInit( new AddressExpr( new VariableExpr( temp ) ) ) );
390 PRINT( std::cerr << "made temp" << i << ": " << newTemp << std::endl; )
391 stmtsToAddBefore.push_back( new DeclStmt( newTemp ) );
392 temp = newTemp;
393 }
394 // update diff so that remaining code works out correctly
395 castExpr->arg = new VariableExpr( temp );
396 PRINT( std::cerr << "update cast to: " << castExpr << std::endl; )
397 srcType = castExpr->arg->result;
398 depth2 = srcType->referenceDepth();
399 diff = depth1 - depth2;
400 assert( diff == 1 );
401 }
402
403 // handle conversion between different depths
404 PRINT (
405 if ( depth1 || depth2 ) {
406 std::cerr << "destType: " << destType << " / srcType: " << srcType << std::endl;
407 std::cerr << "depth: " << depth1 << " / " << depth2 << std::endl;
408 }
409 )
410 if ( diff > 0 ) {
411 // conversion to type with more depth (e.g. int & -> int &&): add address-of for each level of difference
412 Expression * ret = castExpr->arg;
413 for ( int i = 0; i < diff; ++i ) {
414 ret = new AddressExpr( ret );
415 }
416 if ( castExpr->arg->get_lvalue() && ! ResolvExpr::typesCompatible( srcType, strict_dynamic_cast<ReferenceType *>( destType )->base, SymTab::Indexer() ) ) {
417 // must keep cast if cast-to type is different from the actual type
418 castExpr->arg = ret;
419 return castExpr;
420 }
421 ret->env = castExpr->env;
422 delete ret->result;
423 ret->result = castExpr->result;
424 castExpr->env = nullptr;
425 castExpr->arg = nullptr;
426 castExpr->result = nullptr;
427 delete castExpr;
428 return ret;
429 } else if ( diff < 0 ) {
430 // conversion to type with less depth (e.g. int && -> int &): add dereferences for each level of difference
431 diff = -diff; // care only about magnitude now
432 Expression * ret = castExpr->arg;
433 for ( int i = 0; i < diff; ++i ) {
434 ret = mkDeref( ret );
435 // xxx - try removing one reference here? actually, looks like mkDeref already does this, so more closely look at the types generated.
436 }
437 if ( ! ResolvExpr::typesCompatibleIgnoreQualifiers( destType->stripReferences(), srcType->stripReferences(), SymTab::Indexer() ) ) {
438 // must keep cast if types are different
439 castExpr->arg = ret;
440 return castExpr;
441 }
442 ret->env = castExpr->env;
443 delete ret->result;
444 ret->result = castExpr->result;
445 assert( ret->get_lvalue() ); // ensure result is lvalue
446 castExpr->env = nullptr;
447 castExpr->arg = nullptr;
448 castExpr->result = nullptr;
449 delete castExpr;
450 return ret;
451 } else {
452 assert( diff == 0 );
453 // conversion between references of the same depth
454 if ( ResolvExpr::typesCompatible( castExpr->result, castExpr->arg->result, SymTab::Indexer() ) && castExpr->isGenerated ) {
455 // Remove useless generated casts
456 PRINT(
457 std::cerr << "types are compatible, removing cast: " << castExpr << std::endl;
458 std::cerr << "-- " << castExpr->result << std::endl;
459 std::cerr << "-- " << castExpr->arg->result << std::endl;
460 )
461 Expression * ret = castExpr->arg;
462 castExpr->arg = nullptr;
463 std::swap( castExpr->env, ret->env );
464 delete castExpr;
465 return ret;
466 }
467 return castExpr;
468 }
469 }
470
471 Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
472 Type * base = refType->base;
473 Type::Qualifiers qualifiers = refType->get_qualifiers();
474 refType->base = nullptr;
475 delete refType;
476 return new PointerType( qualifiers, base );
477 }
478
479 template<typename Func>
480 Expression * GeneralizedLvalue::applyTransformation( Expression * expr, Expression * arg, Func mkExpr ) {
481 if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( arg ) ) {
482 Expression * arg1 = commaExpr->arg1->clone();
483 Expression * arg2 = commaExpr->arg2->clone();
484 Expression * ret = new CommaExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ) );
485 ret->env = expr->env;
486 expr->env = nullptr;
487 delete expr;
488 return ret;
489 } else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( arg ) ) {
490 Expression * arg1 = condExpr->arg1->clone();
491 Expression * arg2 = condExpr->arg2->clone();
492 Expression * arg3 = condExpr->arg3->clone();
493 ConditionalExpr * ret = new ConditionalExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ), mkExpr( arg3 )->acceptMutator( *visitor ) );
494 ret->env = expr->env;
495 expr->env = nullptr;
496 delete expr;
497
498 // conditional expr type may not be either of the argument types, need to unify
499 using namespace ResolvExpr;
500 Type* commonType = nullptr;
501 TypeEnvironment newEnv;
502 AssertionSet needAssertions, haveAssertions;
503 OpenVarSet openVars;
504 unify( ret->arg2->result, ret->arg3->result, newEnv, needAssertions, haveAssertions, openVars, SymTab::Indexer(), commonType );
505 ret->result = commonType ? commonType : ret->arg2->result->clone();
506 return ret;
507 }
508 return expr;
509 }
510
511 Expression * GeneralizedLvalue::postmutate( MemberExpr * memExpr ) {
512 return applyTransformation( memExpr, memExpr->aggregate, [=]( Expression * aggr ) { return new MemberExpr( memExpr->member, aggr ); } );
513 }
514
515 Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
516 return applyTransformation( addrExpr, addrExpr->arg, []( Expression * arg ) { return new AddressExpr( arg ); } );
517 }
518
519 Expression * CollapseAddrDeref::postmutate( AddressExpr * addrExpr ) {
520 Expression * arg = addrExpr->arg;
521 if ( isIntrinsicReference( arg ) ) {
522 std::string fname = InitTweak::getFunctionName( arg );
523 if ( fname == "*?" ) {
524 Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
525 Expression * ret = arg0;
526 ret->set_env( addrExpr->env );
527 arg0 = nullptr;
528 addrExpr->env = nullptr;
529 delete addrExpr;
530 return ret;
531 }
532 } else if ( CastExpr * castExpr = dynamic_cast< CastExpr * > ( arg ) ) {
533 // need to move cast to pointer type out a level since address of pointer
534 // is not valid C code (can be introduced in prior passes, e.g., InstantiateGeneric)
535 if ( InitTweak::getPointerBase( castExpr->result ) ) {
536 addrExpr->arg = castExpr->arg;
537 castExpr->arg = addrExpr;
538 castExpr->result = new PointerType( Type::Qualifiers(), castExpr->result );
539 return castExpr;
540 }
541 }
542 return addrExpr;
543 }
544
545 Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
546 if ( isIntrinsicReference( appExpr ) ) {
547 std::string fname = InitTweak::getFunctionName( appExpr );
548 if ( fname == "*?" ) {
549 Expression * arg = InitTweak::getCallArg( appExpr, 0 );
550 // xxx - this isn't right, because it can remove casts that should be there...
551 // while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
552 // arg = castExpr->get_arg();
553 // }
554 if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
555 Expression * ret = addrExpr->arg;
556 ret->env = appExpr->env;
557 addrExpr->arg = nullptr;
558 appExpr->env = nullptr;
559 delete appExpr;
560 return ret;
561 }
562 }
563 }
564 return appExpr;
565 }
566 } // namespace
567} // namespace GenPoly
568
569// Local Variables: //
570// tab-width: 4 //
571// mode: c++ //
572// compile-command: "make install" //
573// End: //
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