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source: src/GenPoly/Lvalue.cc @ 2a3d446

ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-astnew-ast-unique-exprpthread-emulationqualifiedEnum

Last change on this file since 2a3d446 was 78cdb06, checked in by Thierry Delisle <tdelisle@…>, 5 years ago
Modified Lvalue cast handling to ignore top level dereferencing in AsmExpr?, also added test case for this fixes #152?
Property mode set to `100644`
File size: 23.5 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	// 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 "InitTweak/InitTweak.h"
24	#include "Parser/LinkageSpec.h" // for Spec, isBuiltin, Intrinsic
25	#include "ResolvExpr/TypeEnvironment.h" // for AssertionSet, OpenVarSet
26	#include "ResolvExpr/Unify.h" // for unify
27	#include "ResolvExpr/typeops.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	#include "Validate/FindSpecialDecls.h" // for dereferenceOperator
36
37	#if 0
38	#define PRINT(x) x
39	#else
40	#define PRINT(x)
41	#endif
42
43	namespace GenPoly {
44	namespace {
45	// TODO: fold this into the general createDeref function??
46	Expression * mkDeref( Expression * arg ) {
47	if ( Validate::dereferenceOperator ) {
48	// 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
49	VariableExpr * deref = new VariableExpr( Validate::dereferenceOperator );
50	deref->result = new PointerType( Type::Qualifiers(), deref->result );
51	Type * base = InitTweak::getPointerBase( arg->result );
52	assertf( base, "expected pointer type in dereference (type was %s)", toString( arg->result ).c_str() );
53	ApplicationExpr * ret = new ApplicationExpr( deref, { arg } );
54	delete ret->result;
55	ret->result = base->clone();
56	return ret;
57	} else {
58	return UntypedExpr::createDeref( arg );
59	}
60	}
61
62	struct ReferenceConversions final : public WithStmtsToAdd, public WithGuards {
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	enum {
74	NoSkip,
75	Skip,
76	SkipInProgress
77	} skip = NoSkip;
78
79	void premutate( AsmExpr * ) { GuardValue( skip ); skip = Skip; }
80	void premutate( ApplicationExpr * ) { GuardValue( skip ); skip = (skip == Skip) ? SkipInProgress : NoSkip; }
81
82
83	Expression * postmutate( ApplicationExpr * appExpr );
84	void premutate( FunctionDecl * funcDecl );
85	bool inIntrinsic = false;
86	};
87
88	/// Replace reference types with pointer types
89	struct ReferenceTypeElimination final {
90	Type * postmutate( ReferenceType * refType );
91	};
92
93	/// GCC-like Generalized Lvalues (which have since been removed from GCC)
94	/// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
95	/// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
96	struct GeneralizedLvalue final : public WithVisitorRef<GeneralizedLvalue> {
97	Expression * postmutate( AddressExpr * addressExpr );
98	Expression * postmutate( MemberExpr * memExpr );
99
100	template<typename Func>
101	Expression * applyTransformation( Expression * expr, Expression * arg, Func mkExpr );
102	};
103
104	/// Removes redundant &/& pattern that this pass can generate
105	struct CollapseAddrDeref final {
106	Expression * postmutate( AddressExpr * addressExpr );
107	Expression * postmutate( ApplicationExpr * appExpr );
108	};
109
110	struct AddrRef final : public WithGuards, public WithVisitorRef<AddrRef>, public WithShortCircuiting {
111	void premutate( AddressExpr * addrExpr );
112	Expression * postmutate( AddressExpr * addrExpr );
113	void premutate( Expression * expr );
114	void premutate( ApplicationExpr * appExpr );
115	void premutate( SingleInit * init );
116
117	void handleNonAddr( Expression * );
118
119	bool first = true;
120	bool current = false;
121	int refDepth = 0;
122	bool addCast = false;
123	};
124	} // namespace
125
126	static bool referencesEliminated = false;
127	// used by UntypedExpr::createDeref to determine whether result type of dereference should be ReferenceType or value type.
128	bool referencesPermissable() {
129	return ! referencesEliminated;
130	}
131
132	void convertLvalue( std::list< Declaration* > & translationUnit ) {
133	PassVisitor<ReferenceConversions> refCvt;
134	PassVisitor<ReferenceTypeElimination> elim;
135	PassVisitor<GeneralizedLvalue> genLval;
136	PassVisitor<FixIntrinsicArgs> fixer;
137	PassVisitor<CollapseAddrDeref> collapser;
138	PassVisitor<AddrRef> addrRef;
139	PassVisitor<FixIntrinsicResult> intrinsicResults;
140	mutateAll( translationUnit, intrinsicResults );
141	mutateAll( translationUnit, addrRef );
142	mutateAll( translationUnit, refCvt );
143	mutateAll( translationUnit, fixer );
144	mutateAll( translationUnit, collapser );
145	mutateAll( translationUnit, genLval );
146	mutateAll( translationUnit, elim ); // last because other passes need reference types to work
147
148	// from this point forward, no other pass should create reference types.
149	referencesEliminated = true;
150	}
151
152	Expression * generalizedLvalue( Expression * expr ) {
153	PassVisitor<GeneralizedLvalue> genLval;
154	return expr->acceptMutator( genLval );
155	}
156
157	namespace {
158	// true for intrinsic function calls that return an lvalue in C
159	bool isIntrinsicReference( Expression * expr ) {
160	// known intrinsic-reference prelude functions
161	static std::set<std::string> lvalueFunctions = { "*?", "?[?]" };
162	if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
163	std::string fname = InitTweak::getFunctionName( untyped );
164	return lvalueFunctions.count(fname);
165	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
166	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
167	return func->linkage == LinkageSpec::Intrinsic && lvalueFunctions.count(func->name);
168	}
169	}
170	return false;
171	}
172
173	Expression * FixIntrinsicResult::postmutate( ApplicationExpr * appExpr ) {
174	if ( skip != SkipInProgress && isIntrinsicReference( appExpr ) ) {
175	// eliminate reference types from intrinsic applications - now they return lvalues
176	ReferenceType * result = strict_dynamic_cast< ReferenceType * >( appExpr->result );
177	appExpr->result = result->base->clone();
178	if ( ! inIntrinsic ) {
179	// when not in an intrinsic function, add a cast to
180	// don't add cast when in an intrinsic function, since they already have the cast
181	Expression * ret = new CastExpr( appExpr, result );
182	std::swap( ret->env, appExpr->env );
183	return ret;
184	}
185	delete result;
186	}
187	return appExpr;
188	}
189
190	void FixIntrinsicResult::premutate( FunctionDecl * funcDecl ) {
191	GuardValue( inIntrinsic );
192	inIntrinsic = funcDecl->linkage == LinkageSpec::Intrinsic;
193	}
194
195	Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
196	// intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
197	if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
198	FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
199	assertf( ftype, "Function declaration does not have function type." );
200	// can be of differing lengths only when function is variadic
201	assertf( ftype->parameters.size() == appExpr->args.size() \|\| ftype->isVarArgs, "ApplicationExpr args do not match formal parameter type." );
202
203
204	unsigned int i = 0;
205	const unsigned int end = ftype->parameters.size();
206
207	/// The for loop may eagerly dereference the iterators and fail on empty lists
208	if(i == end) { return appExpr; }
209	for ( auto p : unsafe_group_iterate( appExpr->args, ftype->parameters ) ) {
210	Expression *& arg = std::get<0>( p );
211	Type * formal = std::get<1>( p )->get_type();
212	PRINT(
213	std::cerr << "pair<0>: " << arg << std::endl;
214	std::cerr << " -- " << arg->result << std::endl;
215	std::cerr << "pair<1>: " << formal << std::endl;
216	)
217	if ( dynamic_cast<ReferenceType*>( formal ) ) {
218	PRINT(
219	std::cerr << "===formal is reference" << std::endl;
220	)
221	// TODO: it's likely that the second condition should be ... && ! isIntrinsicReference( arg ), but this requires investigation.
222
223	if ( function->linkage != LinkageSpec::Intrinsic && isIntrinsicReference( arg ) ) {
224	// needed for definition of prelude functions, etc.
225	// if argument is dereference or array subscript, the result isn't REALLY a reference, but non-intrinsic functions expect a reference: take address
226
227	// NOTE: previously, this condition fixed
228	// void f(int *&);
229	// int & x = ...;
230	// f(&x);
231	// But now this is taken care of by a reference cast added by AddrRef. Need to find a new
232	// example or remove this branch.
233
234	PRINT(
235	std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
236	)
237	arg = new AddressExpr( arg );
238	// } else if ( function->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getPointerBase( arg->result ) ) {
239	} else if ( function->linkage == LinkageSpec::Intrinsic && arg->result->referenceDepth() != 0 ) {
240	// argument is a 'real' reference, but function expects a C lvalue: add a dereference to the reference-typed argument
241	PRINT(
242	std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
243	)
244	Type * baseType = InitTweak::getPointerBase( arg->result );
245	assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
246	PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
247	delete arg->result;
248	arg->result = ptrType;
249	arg = mkDeref( arg );
250	// assertf( arg->result->referenceDepth() == 0, "Reference types should have been eliminated from intrinsic function calls, but weren't: %s", toCString( arg->result ) );
251	}
252	}
253	++i;
254	if (i == end) break;
255	}
256	}
257	return appExpr;
258	}
259
260	// idea: &&&E: get outer &, inner &
261	// at inner &, record depth D of reference type of argument of &
262	// at outer &, add D derefs.
263	void AddrRef::handleNonAddr( Expression * ) {
264	// non-address-of: reset status variables:
265	// * current expr is NOT the first address-of expr in an address-of chain
266	// * next seen address-of expr IS the first in the chain.
267	GuardValue( current );
268	GuardValue( first );
269	current = false;
270	first = true;
271	}
272
273	void AddrRef::premutate( Expression * expr ) {
274	handleNonAddr( expr );
275	GuardValue( addCast );
276	addCast = false;
277	}
278
279	void AddrRef::premutate( AddressExpr * ) {
280	GuardValue( current );
281	GuardValue( first );
282	current = first; // is this the first address-of in the chain?
283	first = false; // from here out, no longer possible for next address-of to be first in chain
284	if ( current ) { // this is the outermost address-of in a chain
285	GuardValue( refDepth );
286	refDepth = 0; // set depth to 0 so that postmutate can find the innermost address-of easily
287	}
288	}
289
290	Expression * AddrRef::postmutate( AddressExpr * addrExpr ) {
291	PRINT( std::cerr << "addr ref at " << addrExpr << std::endl; )
292	if ( refDepth == 0 ) {
293	PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
294	// this is the innermost address-of in a chain, record depth D
295	if ( ! isIntrinsicReference( addrExpr->arg ) ) {
296	// try to avoid ?[?]
297	// 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.
298	refDepth = addrExpr->arg->result->referenceDepth();
299	PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
300	} else {
301	assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( addrExpr->arg ) );
302	}
303	}
304	if ( current ) { // this is the outermost address-of in a chain
305	PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
306	Expression * ret = addrExpr;
307	while ( refDepth ) {
308	// add one dereference for each
309	ret = mkDeref( ret );
310	refDepth--;
311	}
312
313	// if addrExpr depth is 0, then the result is a pointer because the arg was depth 1 and not lvalue.
314	// This means the dereference result is not a reference, is lvalue, and one less pointer depth than
315	// the addrExpr. Thus the cast is meaningless.
316	// TODO: One thing to double check is whether it is possible for the types to differ outside of the single
317	// pointer level (i.e. can the base type of addrExpr differ from the type of addrExpr-arg?).
318	// If so then the cast might need to be added, conditional on a more sophisticated check.
319	if ( addCast && addrExpr->result->referenceDepth() != 0 ) {
320	PRINT( std::cerr << "adding cast to " << addrExpr->result << std::endl; )
321	return new CastExpr( ret, addrExpr->result->clone() );
322	}
323	return ret;
324	}
325	PRINT( std::cerr << "not current..." << std::endl; )
326	return addrExpr;
327	}
328
329	void AddrRef::premutate( ApplicationExpr * appExpr ) {
330	visit_children = false;
331	GuardValue( addCast );
332	handleNonAddr( appExpr );
333	for ( Expression *& arg : appExpr->args ) {
334	// each argument with address-of requires a cast
335	addCast = true;
336	arg = arg->acceptMutator( *visitor );
337	}
338	}
339
340	void AddrRef::premutate( SingleInit * ) {
341	GuardValue( addCast );
342	// each initialization context with address-of requires a cast
343	addCast = true;
344	}
345
346
347	Expression * ReferenceConversions::postmutate( AddressExpr * addrExpr ) {
348	// Inner expression may have been lvalue to reference conversion, which becomes an address expression.
349	// In this case, remove the outer address expression and return the argument.
350	// TODO: It's possible that this might catch too much and require a more sophisticated check.
351	return addrExpr;
352	}
353
354	Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
355	// xxx - is it possible to convert directly between reference types with a different base? E.g.,
356	// int x;
357	// (double&)x;
358	// At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
359	// after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
360	// pointer casts in the right places.
361
362	// Note: reference depth difference is the determining factor in what code is run, rather than whether something is
363	// reference type or not, since conversion still needs to occur when both types are references that differ in depth.
364
365	Type * destType = castExpr->result;
366	Type * srcType = castExpr->arg->result;
367	assertf( destType, "Cast to no type in: %s", toCString( castExpr ) );
368	assertf( srcType, "Cast from no type in: %s", toCString( castExpr ) );
369	int depth1 = destType->referenceDepth();
370	int depth2 = srcType->referenceDepth();
371	int diff = depth1 - depth2;
372
373	if ( diff > 0 && ! castExpr->arg->get_lvalue() ) {
374	// rvalue to reference conversion -- introduce temporary
375	// know that reference depth of cast argument is 0, need to introduce n temporaries for reference depth of n, e.g.
376	// (int &&&)3;
377	// becomes
378	// int __ref_tmp_0 = 3;
379	// int & __ref_tmp_1 = _&_ref_tmp_0;
380	// int && __ref_tmp_2 = &__ref_tmp_1;
381	// &__ref_tmp_2;
382	// the last & comes from the remaining reference conversion code
383	SemanticWarning( castExpr->arg->location, Warning::RvalueToReferenceConversion, toCString( castExpr->arg ) );
384
385	static UniqueName tempNamer( "__ref_tmp_" );
386	ObjectDecl * temp = ObjectDecl::newObject( tempNamer.newName(), castExpr->arg->result->clone(), new SingleInit( castExpr->arg ) );
387	PRINT( std::cerr << "made temp: " << temp << std::endl; )
388	stmtsToAddBefore.push_back( new DeclStmt( temp ) );
389	for ( int i = 0; i < depth1-1; i++ ) { // xxx - maybe this should be diff-1? check how this works with reference type for srcType
390	ObjectDecl * newTemp = ObjectDecl::newObject( tempNamer.newName(), new ReferenceType( Type::Qualifiers(), temp->type->clone() ), new SingleInit( new AddressExpr( new VariableExpr( temp ) ) ) );
391	PRINT( std::cerr << "made temp" << i << ": " << newTemp << std::endl; )
392	stmtsToAddBefore.push_back( new DeclStmt( newTemp ) );
393	temp = newTemp;
394	}
395	// update diff so that remaining code works out correctly
396	castExpr->arg = new VariableExpr( temp );
397	PRINT( std::cerr << "update cast to: " << castExpr << std::endl; )
398	srcType = castExpr->arg->result;
399	depth2 = srcType->referenceDepth();
400	diff = depth1 - depth2;
401	assert( diff == 1 );
402	}
403
404	// handle conversion between different depths
405	PRINT (
406	if ( depth1 \|\| depth2 ) {
407	std::cerr << "destType: " << destType << " / srcType: " << srcType << std::endl;
408	std::cerr << "depth: " << depth1 << " / " << depth2 << std::endl;
409	}
410	)
411	if ( diff > 0 ) {
412	// conversion to type with more depth (e.g. int & -> int &&): add address-of for each level of difference
413	Expression * ret = castExpr->arg;
414	for ( int i = 0; i < diff; ++i ) {
415	ret = new AddressExpr( ret );
416	}
417	if ( castExpr->arg->get_lvalue() && ! ResolvExpr::typesCompatible( srcType, strict_dynamic_cast<ReferenceType *>( destType )->base, SymTab::Indexer() ) ) {
418	// must keep cast if cast-to type is different from the actual type
419	castExpr->arg = ret;
420	return castExpr;
421	}
422	ret->env = castExpr->env;
423	delete ret->result;
424	ret->result = castExpr->result;
425	castExpr->env = nullptr;
426	castExpr->arg = nullptr;
427	castExpr->result = nullptr;
428	delete castExpr;
429	return ret;
430	} else if ( diff < 0 ) {
431	// conversion to type with less depth (e.g. int && -> int &): add dereferences for each level of difference
432	diff = -diff; // care only about magnitude now
433	Expression * ret = castExpr->arg;
434	for ( int i = 0; i < diff; ++i ) {
435	ret = mkDeref( ret );
436	// xxx - try removing one reference here? actually, looks like mkDeref already does this, so more closely look at the types generated.
437	}
438	if ( ! ResolvExpr::typesCompatibleIgnoreQualifiers( destType->stripReferences(), srcType->stripReferences(), SymTab::Indexer() ) ) {
439	// must keep cast if types are different
440	castExpr->arg = ret;
441	return castExpr;
442	}
443	ret->env = castExpr->env;
444	delete ret->result;
445	ret->result = castExpr->result;
446	assert( ret->get_lvalue() ); // ensure result is lvalue
447	castExpr->env = nullptr;
448	castExpr->arg = nullptr;
449	castExpr->result = nullptr;
450	delete castExpr;
451	return ret;
452	} else {
453	assert( diff == 0 );
454	// conversion between references of the same depth
455	if ( ResolvExpr::typesCompatible( castExpr->result, castExpr->arg->result, SymTab::Indexer() ) && castExpr->isGenerated ) {
456	// Remove useless generated casts
457	PRINT(
458	std::cerr << "types are compatible, removing cast: " << castExpr << std::endl;
459	std::cerr << "-- " << castExpr->result << std::endl;
460	std::cerr << "-- " << castExpr->arg->result << std::endl;
461	)
462	Expression * ret = castExpr->arg;
463	castExpr->arg = nullptr;
464	std::swap( castExpr->env, ret->env );
465	delete castExpr;
466	return ret;
467	}
468	return castExpr;
469	}
470	}
471
472	Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
473	Type * base = refType->base;
474	Type::Qualifiers qualifiers = refType->get_qualifiers();
475	refType->base = nullptr;
476	delete refType;
477	return new PointerType( qualifiers, base );
478	}
479
480	template<typename Func>
481	Expression * GeneralizedLvalue::applyTransformation( Expression * expr, Expression * arg, Func mkExpr ) {
482	if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( arg ) ) {
483	Expression * arg1 = commaExpr->arg1->clone();
484	Expression * arg2 = commaExpr->arg2->clone();
485	Expression * ret = new CommaExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ) );
486	ret->env = expr->env;
487	expr->env = nullptr;
488	delete expr;
489	return ret;
490	} else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( arg ) ) {
491	Expression * arg1 = condExpr->arg1->clone();
492	Expression * arg2 = condExpr->arg2->clone();
493	Expression * arg3 = condExpr->arg3->clone();
494	ConditionalExpr * ret = new ConditionalExpr( arg1, mkExpr( arg2 )->acceptMutator( visitor ), mkExpr( arg3 )->acceptMutator( visitor ) );
495	ret->env = expr->env;
496	expr->env = nullptr;
497	delete expr;
498
499	// conditional expr type may not be either of the argument types, need to unify
500	using namespace ResolvExpr;
501	Type* commonType = nullptr;
502	TypeEnvironment newEnv;
503	AssertionSet needAssertions, haveAssertions;
504	OpenVarSet openVars;
505	unify( ret->arg2->result, ret->arg3->result, newEnv, needAssertions, haveAssertions, openVars, SymTab::Indexer(), commonType );
506	ret->result = commonType ? commonType : ret->arg2->result->clone();
507	return ret;
508	}
509	return expr;
510	}
511
512	Expression * GeneralizedLvalue::postmutate( MemberExpr * memExpr ) {
513	return applyTransformation( memExpr, memExpr->aggregate, [=]( Expression * aggr ) { return new MemberExpr( memExpr->member, aggr ); } );
514	}
515
516	Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
517	return applyTransformation( addrExpr, addrExpr->arg, []( Expression * arg ) { return new AddressExpr( arg ); } );
518	}
519
520	Expression * CollapseAddrDeref::postmutate( AddressExpr * addrExpr ) {
521	Expression * arg = addrExpr->arg;
522	if ( isIntrinsicReference( arg ) ) {
523	std::string fname = InitTweak::getFunctionName( arg );
524	if ( fname == "*?" ) {
525	Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
526	Expression * ret = arg0;
527	ret->set_env( addrExpr->env );
528	arg0 = nullptr;
529	addrExpr->env = nullptr;
530	delete addrExpr;
531	return ret;
532	}
533	} else if ( CastExpr * castExpr = dynamic_cast< CastExpr * > ( arg ) ) {
534	// need to move cast to pointer type out a level since address of pointer
535	// is not valid C code (can be introduced in prior passes, e.g., InstantiateGeneric)
536	if ( InitTweak::getPointerBase( castExpr->result ) ) {
537	addrExpr->arg = castExpr->arg;
538	castExpr->arg = addrExpr;
539	castExpr->result = new PointerType( Type::Qualifiers(), castExpr->result );
540	return castExpr;
541	}
542	}
543	return addrExpr;
544	}
545
546	Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
547	if ( isIntrinsicReference( appExpr ) ) {
548	std::string fname = InitTweak::getFunctionName( appExpr );
549	if ( fname == "*?" ) {
550	Expression * arg = InitTweak::getCallArg( appExpr, 0 );
551	// xxx - this isn't right, because it can remove casts that should be there...
552	// while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
553	// arg = castExpr->get_arg();
554	// }
555	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
556	Expression * ret = addrExpr->arg;
557	ret->env = appExpr->env;
558	addrExpr->arg = nullptr;
559	appExpr->env = nullptr;
560	delete appExpr;
561	return ret;
562	}
563	}
564	}
565	return appExpr;
566	}
567	} // namespace
568	} // namespace GenPoly
569
570	// Local Variables: //
571	// tab-width: 4 //
572	// mode: c++ //
573	// compile-command: "make install" //
574	// End: //

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