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source: src/GenPoly/Lvalue.cc @ 16948499

ADTarm-ehast-experimentalcleanup-dtorsenumforall-pointer-decayjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-exprpthread-emulationqualifiedEnum

Last change on this file since 16948499 was 85b2300, checked in by Rob Schluntz <rschlunt@…>, 6 years ago
Minor code cleanup
Property mode set to `100644`
File size: 23.0 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 : Peter A. Buhr
12	// Last Modified On : Fri Mar 17 09:11:18 2017
13	// Update Count : 5
14	//
15
16	#include <cassert> // for strict_dynamic_cast
17	#include <string> // for string
18
19	#include "Common/PassVisitor.h"
20	#include "GenPoly.h" // for isPolyType
21	#include "Lvalue.h"
22
23	#include "Parser/LinkageSpec.h" // for Spec, isBuiltin, Intrinsic
24	#include "ResolvExpr/TypeEnvironment.h" // for AssertionSet, OpenVarSet
25	#include "ResolvExpr/Unify.h" // for unify
26	#include "ResolvExpr/typeops.h"
27	#include "SymTab/Autogen.h"
28	#include "SymTab/Indexer.h" // for Indexer
29	#include "SynTree/Declaration.h" // for Declaration, FunctionDecl
30	#include "SynTree/Expression.h" // for Expression, ConditionalExpr
31	#include "SynTree/Mutator.h" // for mutateAll, Mutator
32	#include "SynTree/Statement.h" // for ReturnStmt, Statement (ptr o...
33	#include "SynTree/Type.h" // for PointerType, Type, FunctionType
34	#include "SynTree/Visitor.h" // for Visitor, acceptAll
35
36	#if 0
37	#define PRINT(x) x
38	#else
39	#define PRINT(x)
40	#endif
41
42	namespace GenPoly {
43	namespace {
44	// TODO: fold this into the general createDeref function??
45	Expression * mkDeref( Expression * arg ) {
46	if ( SymTab::dereferenceOperator ) {
47	// 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
48	VariableExpr * deref = new VariableExpr( SymTab::dereferenceOperator );
49	deref->result = new PointerType( Type::Qualifiers(), deref->result );
50	Type * base = InitTweak::getPointerBase( arg->result );
51	assertf( base, "expected pointer type in dereference (type was %s)", toString( arg->result ).c_str() );
52	ApplicationExpr * ret = new ApplicationExpr( deref, { arg } );
53	delete ret->result;
54	ret->result = base->clone();
55	ret->result->set_lvalue( true );
56	return ret;
57	} else {
58	return UntypedExpr::createDeref( arg );
59	}
60	}
61
62	struct ReferenceConversions final : public WithStmtsToAdd {
63	Expression * postmutate( CastExpr * castExpr );
64	Expression * postmutate( AddressExpr * addrExpr );
65	};
66
67	/// Intrinsic functions that take reference parameters don't REALLY take reference parameters -- their reference arguments must always be implicitly dereferenced.
68	struct FixIntrinsicArgs final {
69	Expression * postmutate( ApplicationExpr * appExpr );
70	};
71
72	struct FixIntrinsicResult final : public WithGuards {
73	Expression * postmutate( ApplicationExpr * appExpr );
74	void premutate( FunctionDecl * funcDecl );
75	bool inIntrinsic = false;
76	};
77
78	/// Replace reference types with pointer types
79	struct ReferenceTypeElimination final {
80	Type * postmutate( ReferenceType * refType );
81	};
82
83	/// GCC-like Generalized Lvalues (which have since been removed from GCC)
84	/// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
85	/// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
86	struct GeneralizedLvalue final : public WithVisitorRef<GeneralizedLvalue> {
87	Expression * postmutate( AddressExpr * addressExpr );
88	Expression * postmutate( MemberExpr * memExpr );
89
90	template<typename Func>
91	Expression * applyTransformation( Expression * expr, Expression * arg, Func mkExpr );
92	};
93
94	/// Removes redundant &/& pattern that this pass can generate
95	struct CollapseAddrDeref final {
96	Expression * postmutate( AddressExpr * addressExpr );
97	Expression * postmutate( ApplicationExpr * appExpr );
98	};
99
100	struct AddrRef final : public WithGuards, public WithVisitorRef<AddrRef>, public WithShortCircuiting {
101	void premutate( AddressExpr * addrExpr );
102	Expression * postmutate( AddressExpr * addrExpr );
103	void premutate( Expression * expr );
104	void premutate( ApplicationExpr * appExpr );
105	void premutate( SingleInit * init );
106
107	void handleNonAddr( Expression * );
108
109	bool first = true;
110	bool current = false;
111	int refDepth = 0;
112	bool addCast = false;
113	};
114	} // namespace
115
116	static bool referencesEliminated = false;
117	// used by UntypedExpr::createDeref to determine whether result type of dereference should be ReferenceType or value type.
118	bool referencesPermissable() {
119	return ! referencesEliminated;
120	}
121
122	void convertLvalue( std::list< Declaration* > & translationUnit ) {
123	PassVisitor<ReferenceConversions> refCvt;
124	PassVisitor<ReferenceTypeElimination> elim;
125	PassVisitor<GeneralizedLvalue> genLval;
126	PassVisitor<FixIntrinsicArgs> fixer;
127	PassVisitor<CollapseAddrDeref> collapser;
128	PassVisitor<AddrRef> addrRef;
129	PassVisitor<FixIntrinsicResult> intrinsicResults;
130	mutateAll( translationUnit, intrinsicResults );
131	mutateAll( translationUnit, addrRef );
132	mutateAll( translationUnit, refCvt );
133	mutateAll( translationUnit, fixer );
134	mutateAll( translationUnit, collapser );
135	mutateAll( translationUnit, genLval );
136	mutateAll( translationUnit, elim ); // last because other passes need reference types to work
137
138	// from this point forward, no other pass should create reference types.
139	referencesEliminated = true;
140	}
141
142	Expression * generalizedLvalue( Expression * expr ) {
143	PassVisitor<GeneralizedLvalue> genLval;
144	return expr->acceptMutator( genLval );
145	}
146
147	namespace {
148	// true for intrinsic function calls that return an lvalue in C
149	bool isIntrinsicReference( Expression * expr ) {
150	// known intrinsic-reference prelude functions
151	static std::set<std::string> lvalueFunctions = { "*?", "?[?]" };
152	if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
153	std::string fname = InitTweak::getFunctionName( untyped );
154	return lvalueFunctions.count(fname);
155	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
156	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
157	return func->linkage == LinkageSpec::Intrinsic && lvalueFunctions.count(func->name);
158	}
159	}
160	return false;
161	}
162
163	Expression * FixIntrinsicResult::postmutate( ApplicationExpr * appExpr ) {
164	if ( isIntrinsicReference( appExpr ) ) {
165	// eliminate reference types from intrinsic applications - now they return lvalues
166	ReferenceType * result = strict_dynamic_cast< ReferenceType * >( appExpr->result );
167	appExpr->result = result->base->clone();
168	appExpr->result->set_lvalue( true );
169	if ( ! inIntrinsic ) {
170	// when not in an intrinsic function, add a cast to
171	// don't add cast when in an intrinsic function, since they already have the cast
172	Expression * ret = new CastExpr( appExpr, result );
173	std::swap( ret->env, appExpr->env );
174	return ret;
175	}
176	delete result;
177	}
178	return appExpr;
179	}
180
181	void FixIntrinsicResult::premutate( FunctionDecl * funcDecl ) {
182	GuardValue( inIntrinsic );
183	inIntrinsic = funcDecl->linkage == LinkageSpec::Intrinsic;
184	}
185
186	Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
187	// intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
188	if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
189	FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
190	assertf( ftype, "Function declaration does not have function type." );
191	// can be of differing lengths only when function is variadic
192	assertf( ftype->parameters.size() == appExpr->args.size() \|\| ftype->isVarArgs, "ApplicationExpr args do not match formal parameter type." );
193
194
195	unsigned int i = 0;
196	const unsigned int end = ftype->parameters.size();
197	for ( auto p : unsafe_group_iterate( appExpr->args, ftype->parameters ) ) {
198	if (i == end) break;
199	Expression *& arg = std::get<0>( p );
200	Type * formal = std::get<1>( p )->get_type();
201	PRINT(
202	std::cerr << "pair<0>: " << arg << std::endl;
203	std::cerr << " -- " << arg->result << std::endl;
204	std::cerr << "pair<1>: " << formal << std::endl;
205	)
206	if ( dynamic_cast<ReferenceType*>( formal ) ) {
207	PRINT(
208	std::cerr << "===formal is reference" << std::endl;
209	)
210	// TODO: it's likely that the second condition should be ... && ! isIntrinsicReference( arg ), but this requires investigation.
211
212	if ( function->linkage != LinkageSpec::Intrinsic && isIntrinsicReference( arg ) ) {
213	// needed for definition of prelude functions, etc.
214	// if argument is dereference or array subscript, the result isn't REALLY a reference, but non-intrinsic functions expect a reference: take address
215
216	// NOTE: previously, this condition fixed
217	// void f(int *&);
218	// int & x = ...;
219	// f(&x);
220	// But now this is taken care of by a reference cast added by AddrRef. Need to find a new
221	// example or remove this branch.
222
223	PRINT(
224	std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
225	)
226	arg = new AddressExpr( arg );
227	// } else if ( function->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getPointerBase( arg->result ) ) {
228	} else if ( function->linkage == LinkageSpec::Intrinsic && arg->result->referenceDepth() != 0 ) {
229	// argument is a 'real' reference, but function expects a C lvalue: add a dereference to the reference-typed argument
230	PRINT(
231	std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
232	)
233	Type * baseType = InitTweak::getPointerBase( arg->result );
234	assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
235	PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
236	delete arg->result;
237	arg->result = ptrType;
238	arg = mkDeref( arg );
239	// assertf( arg->result->referenceDepth() == 0, "Reference types should have been eliminated from intrinsic function calls, but weren't: %s", toCString( arg->result ) );
240	}
241	}
242	++i;
243	}
244	}
245	return appExpr;
246	}
247
248	// idea: &&&E: get outer &, inner &
249	// at inner &, record depth D of reference type of argument of &
250	// at outer &, add D derefs.
251	void AddrRef::handleNonAddr( Expression * ) {
252	// non-address-of: reset status variables:
253	// * current expr is NOT the first address-of expr in an address-of chain
254	// * next seen address-of expr IS the first in the chain.
255	GuardValue( current );
256	GuardValue( first );
257	current = false;
258	first = true;
259	}
260
261	void AddrRef::premutate( Expression * expr ) {
262	handleNonAddr( expr );
263	GuardValue( addCast );
264	addCast = false;
265	}
266
267	void AddrRef::premutate( AddressExpr * ) {
268	GuardValue( current );
269	GuardValue( first );
270	current = first; // is this the first address-of in the chain?
271	first = false; // from here out, no longer possible for next address-of to be first in chain
272	if ( current ) { // this is the outermost address-of in a chain
273	GuardValue( refDepth );
274	refDepth = 0; // set depth to 0 so that postmutate can find the innermost address-of easily
275	}
276	}
277
278	Expression * AddrRef::postmutate( AddressExpr * addrExpr ) {
279	PRINT( std::cerr << "addr ref at " << addrExpr << std::endl; )
280	if ( refDepth == 0 ) {
281	PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
282	// this is the innermost address-of in a chain, record depth D
283	if ( ! isIntrinsicReference( addrExpr->arg ) ) {
284	// try to avoid ?[?]
285	// 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.
286	refDepth = addrExpr->arg->result->referenceDepth();
287	PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
288	} else {
289	assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( addrExpr->arg ) );
290	}
291	}
292	if ( current ) { // this is the outermost address-of in a chain
293	PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
294	Expression * ret = addrExpr;
295	while ( refDepth ) {
296	// add one dereference for each
297	ret = mkDeref( ret );
298	refDepth--;
299	}
300
301	// if addrExpr depth is 0, then the result is a pointer because the arg was depth 1 and not lvalue.
302	// This means the dereference result is not a reference, is lvalue, and one less pointer depth than
303	// the addrExpr. Thus the cast is meaningless.
304	// TODO: One thing to double check is whether it is possible for the types to differ outside of the single
305	// pointer level (i.e. can the base type of addrExpr differ from the type of addrExpr-arg?).
306	// If so then the cast might need to be added, conditional on a more sophisticated check.
307	if ( addCast && addrExpr->result->referenceDepth() != 0 ) {
308	PRINT( std::cerr << "adding cast to " << addrExpr->result << std::endl; )
309	return new CastExpr( ret, addrExpr->result->clone() );
310	}
311	return ret;
312	}
313	PRINT( std::cerr << "not current..." << std::endl; )
314	return addrExpr;
315	}
316
317	void AddrRef::premutate( ApplicationExpr * appExpr ) {
318	visit_children = false;
319	GuardValue( addCast );
320	handleNonAddr( appExpr );
321	for ( Expression *& arg : appExpr->args ) {
322	// each argument with address-of requires a cast
323	addCast = true;
324	arg = arg->acceptMutator( *visitor );
325	}
326	}
327
328	void AddrRef::premutate( SingleInit * ) {
329	GuardValue( addCast );
330	// each initialization context with address-of requires a cast
331	addCast = true;
332	}
333
334
335	Expression * ReferenceConversions::postmutate( AddressExpr * addrExpr ) {
336	// Inner expression may have been lvalue to reference conversion, which becomes an address expression.
337	// In this case, remove the outer address expression and return the argument.
338	// TODO: It's possible that this might catch too much and require a more sophisticated check.
339	return addrExpr;
340	}
341
342	Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
343	// xxx - is it possible to convert directly between reference types with a different base? E.g.,
344	// int x;
345	// (double&)x;
346	// At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
347	// after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
348	// pointer casts in the right places.
349
350	// Note: reference depth difference is the determining factor in what code is run, rather than whether something is
351	// reference type or not, since conversion still needs to occur when both types are references that differ in depth.
352
353	Type * destType = castExpr->result;
354	Type * srcType = castExpr->arg->result;
355	int depth1 = destType->referenceDepth();
356	int depth2 = srcType->referenceDepth();
357	int diff = depth1 - depth2;
358
359	if ( diff > 0 && ! srcType->get_lvalue() ) {
360	// rvalue to reference conversion -- introduce temporary
361	// know that reference depth of cast argument is 0, need to introduce n temporaries for reference depth of n, e.g.
362	// (int &&&)3;
363	// becomes
364	// int __ref_tmp_0 = 3;
365	// int & __ref_tmp_1 = _&_ref_tmp_0;
366	// int && __ref_tmp_2 = &__ref_tmp_1;
367	// &__ref_tmp_2;
368	// the last & comes from the remaining reference conversion code
369	SemanticWarning( castExpr->arg->location, Warning::RvalueToReferenceConversion, toCString( castExpr->arg ) );
370
371	static UniqueName tempNamer( "__ref_tmp_" );
372	ObjectDecl * temp = ObjectDecl::newObject( tempNamer.newName(), castExpr->arg->result->clone(), new SingleInit( castExpr->arg ) );
373	PRINT( std::cerr << "made temp: " << temp << std::endl; )
374	stmtsToAddBefore.push_back( new DeclStmt( temp ) );
375	for ( int i = 0; i < depth1-1; i++ ) { // xxx - maybe this should be diff-1? check how this works with reference type for srcType
376	ObjectDecl * newTemp = ObjectDecl::newObject( tempNamer.newName(), new ReferenceType( Type::Qualifiers(), temp->type->clone() ), new SingleInit( new AddressExpr( new VariableExpr( temp ) ) ) );
377	PRINT( std::cerr << "made temp" << i << ": " << newTemp << std::endl; )
378	stmtsToAddBefore.push_back( new DeclStmt( newTemp ) );
379	temp = newTemp;
380	}
381	// update diff so that remaining code works out correctly
382	castExpr->arg = new VariableExpr( temp );
383	PRINT( std::cerr << "update cast to: " << castExpr << std::endl; )
384	srcType = castExpr->arg->result;
385	depth2 = srcType->referenceDepth();
386	diff = depth1 - depth2;
387	assert( diff == 1 );
388	}
389
390	// handle conversion between different depths
391	PRINT (
392	if ( depth1 \|\| depth2 ) {
393	std::cerr << "destType: " << destType << " / srcType: " << srcType << std::endl;
394	std::cerr << "depth: " << depth1 << " / " << depth2 << std::endl;
395	}
396	)
397	if ( diff > 0 ) {
398	// conversion to type with more depth (e.g. int & -> int &&): add address-of for each level of difference
399	Expression * ret = castExpr->arg;
400	for ( int i = 0; i < diff; ++i ) {
401	ret = new AddressExpr( ret );
402	}
403	if ( srcType->get_lvalue() && ! ResolvExpr::typesCompatible( srcType, strict_dynamic_cast<ReferenceType *>( destType )->base, SymTab::Indexer() ) ) {
404	// must keep cast if cast-to type is different from the actual type
405	castExpr->arg = ret;
406	return castExpr;
407	}
408	ret->env = castExpr->env;
409	delete ret->result;
410	ret->result = castExpr->result;
411	castExpr->env = nullptr;
412	castExpr->arg = nullptr;
413	castExpr->result = nullptr;
414	delete castExpr;
415	return ret;
416	} else if ( diff < 0 ) {
417	// conversion to type with less depth (e.g. int && -> int &): add dereferences for each level of difference
418	diff = -diff; // care only about magnitude now
419	Expression * ret = castExpr->arg;
420	for ( int i = 0; i < diff; ++i ) {
421	ret = mkDeref( ret );
422	// xxx - try removing one reference here? actually, looks like mkDeref already does this, so more closely look at the types generated.
423	}
424	if ( ! ResolvExpr::typesCompatibleIgnoreQualifiers( destType->stripReferences(), srcType->stripReferences(), SymTab::Indexer() ) ) {
425	// must keep cast if types are different
426	castExpr->arg = ret;
427	return castExpr;
428	}
429	ret->env = castExpr->env;
430	delete ret->result;
431	ret->result = castExpr->result;
432	ret->result->set_lvalue( true ); // ensure result is lvalue
433	castExpr->env = nullptr;
434	castExpr->arg = nullptr;
435	castExpr->result = nullptr;
436	delete castExpr;
437	return ret;
438	} else {
439	assert( diff == 0 );
440	// conversion between references of the same depth
441	if ( ResolvExpr::typesCompatible( castExpr->result, castExpr->arg->result, SymTab::Indexer() ) && castExpr->isGenerated ) {
442	// Remove useless generated casts
443	PRINT(
444	std::cerr << "types are compatible, removing cast: " << castExpr << std::endl;
445	std::cerr << "-- " << castExpr->result << std::endl;
446	std::cerr << "-- " << castExpr->arg->result << std::endl;
447	)
448	Expression * ret = castExpr->arg;
449	castExpr->arg = nullptr;
450	std::swap( castExpr->env, ret->env );
451	delete castExpr;
452	return ret;
453	}
454	return castExpr;
455	}
456	}
457
458	Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
459	Type * base = refType->base;
460	Type::Qualifiers qualifiers = refType->get_qualifiers();
461	refType->base = nullptr;
462	delete refType;
463	return new PointerType( qualifiers, base );
464	}
465
466	template<typename Func>
467	Expression * GeneralizedLvalue::applyTransformation( Expression * expr, Expression * arg, Func mkExpr ) {
468	if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( arg ) ) {
469	Expression * arg1 = commaExpr->arg1->clone();
470	Expression * arg2 = commaExpr->arg2->clone();
471	Expression * ret = new CommaExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ) );
472	ret->env = expr->env;
473	expr->env = nullptr;
474	delete expr;
475	return ret;
476	} else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( arg ) ) {
477	Expression * arg1 = condExpr->arg1->clone();
478	Expression * arg2 = condExpr->arg2->clone();
479	Expression * arg3 = condExpr->arg3->clone();
480	ConditionalExpr * ret = new ConditionalExpr( arg1, mkExpr( arg2 )->acceptMutator( visitor ), mkExpr( arg3 )->acceptMutator( visitor ) );
481	ret->env = expr->env;
482	expr->env = nullptr;
483	delete expr;
484
485	// conditional expr type may not be either of the argument types, need to unify
486	using namespace ResolvExpr;
487	Type* commonType = nullptr;
488	TypeEnvironment newEnv;
489	AssertionSet needAssertions, haveAssertions;
490	OpenVarSet openVars;
491	unify( ret->arg2->result, ret->arg3->result, newEnv, needAssertions, haveAssertions, openVars, SymTab::Indexer(), commonType );
492	ret->result = commonType ? commonType : ret->arg2->result->clone();
493	return ret;
494	}
495	return expr;
496	}
497
498	Expression * GeneralizedLvalue::postmutate( MemberExpr * memExpr ) {
499	return applyTransformation( memExpr, memExpr->aggregate, [=]( Expression * aggr ) { return new MemberExpr( memExpr->member, aggr ); } );
500	}
501
502	Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
503	return applyTransformation( addrExpr, addrExpr->arg, []( Expression * arg ) { return new AddressExpr( arg ); } );
504	}
505
506	Expression * CollapseAddrDeref::postmutate( AddressExpr * addrExpr ) {
507	Expression * arg = addrExpr->arg;
508	if ( isIntrinsicReference( arg ) ) {
509	std::string fname = InitTweak::getFunctionName( arg );
510	if ( fname == "*?" ) {
511	Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
512	Expression * ret = arg0;
513	ret->set_env( addrExpr->env );
514	arg0 = nullptr;
515	addrExpr->env = nullptr;
516	delete addrExpr;
517	return ret;
518	}
519	} else if ( CastExpr * castExpr = dynamic_cast< CastExpr * > ( arg ) ) {
520	// need to move cast to pointer type out a level since address of pointer
521	// is not valid C code (can be introduced in prior passes, e.g., InstantiateGeneric)
522	if ( InitTweak::getPointerBase( castExpr->result ) ) {
523	addrExpr->arg = castExpr->arg;
524	castExpr->arg = addrExpr;
525	castExpr->result = new PointerType( Type::Qualifiers(), castExpr->result );
526	return castExpr;
527	}
528	}
529	return addrExpr;
530	}
531
532	Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
533	if ( isIntrinsicReference( appExpr ) ) {
534	std::string fname = InitTweak::getFunctionName( appExpr );
535	if ( fname == "*?" ) {
536	Expression * arg = InitTweak::getCallArg( appExpr, 0 );
537	// xxx - this isn't right, because it can remove casts that should be there...
538	// while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
539	// arg = castExpr->get_arg();
540	// }
541	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
542	Expression * ret = addrExpr->arg;
543	ret->env = appExpr->env;
544	addrExpr->arg = nullptr;
545	appExpr->env = nullptr;
546	delete appExpr;
547	return ret;
548	}
549	}
550	}
551	return appExpr;
552	}
553	} // namespace
554	} // namespace GenPoly
555
556	// Local Variables: //
557	// tab-width: 4 //
558	// mode: c++ //
559	// compile-command: "make install" //
560	// End: //

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