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source: src/GenPoly/Lvalue.cc @ 1f45c7d

ADTast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-ast-unique-exprpthread-emulationqualifiedEnum

Last change on this file since 1f45c7d was 07de76b, checked in by Peter A. Buhr <pabuhr@…>, 5 years ago
remove file TypeVar?.h* and put TypeVar::Kind into TypeDecl?, move LinkageSpec?.* from directory Parse to SynTree?
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 Dec 13 23:14:38 2019
13	// Update Count : 7
14	//
15
16	#include <cassert> // for strict_dynamic_cast
17	#include <string> // for string
18
19	#include "Common/UniqueName.h"
20	#include "Common/PassVisitor.h"
21	#include "GenPoly.h" // for isPolyType
22	#include "Lvalue.h"
23
24	#include "InitTweak/InitTweak.h"
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/LinkageSpec.h" // for Spec, isBuiltin, Intrinsic
30	#include "SynTree/Declaration.h" // for Declaration, FunctionDecl
31	#include "SynTree/Expression.h" // for Expression, ConditionalExpr
32	#include "SynTree/Mutator.h" // for mutateAll, Mutator
33	#include "SynTree/Statement.h" // for ReturnStmt, Statement (ptr o...
34	#include "SynTree/Type.h" // for PointerType, Type, FunctionType
35	#include "SynTree/Visitor.h" // for Visitor, acceptAll
36	#include "Validate/FindSpecialDecls.h" // for dereferenceOperator
37
38	#if 0
39	#define PRINT(x) x
40	#else
41	#define PRINT(x)
42	#endif
43
44	namespace GenPoly {
45	namespace {
46	// TODO: fold this into the general createDeref function??
47	Expression * mkDeref( Expression * arg ) {
48	if ( Validate::dereferenceOperator ) {
49	// 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
50	VariableExpr * deref = new VariableExpr( Validate::dereferenceOperator );
51	deref->result = new PointerType( Type::Qualifiers(), deref->result );
52	Type * base = InitTweak::getPointerBase( arg->result );
53	assertf( base, "expected pointer type in dereference (type was %s)", toString( arg->result ).c_str() );
54	ApplicationExpr * ret = new ApplicationExpr( deref, { arg } );
55	delete ret->result;
56	ret->result = base->clone();
57	return ret;
58	} else {
59	return UntypedExpr::createDeref( arg );
60	}
61	}
62
63	struct ReferenceConversions final : public WithStmtsToAdd, public WithGuards {
64	Expression * postmutate( CastExpr * castExpr );
65	Expression * postmutate( AddressExpr * addrExpr );
66	};
67
68	/// Intrinsic functions that take reference parameters don't REALLY take reference parameters -- their reference arguments must always be implicitly dereferenced.
69	struct FixIntrinsicArgs final {
70	Expression * postmutate( ApplicationExpr * appExpr );
71	};
72
73	struct FixIntrinsicResult final : public WithGuards {
74	enum {
75	NoSkip,
76	Skip,
77	SkipInProgress
78	} skip = NoSkip;
79
80	void premutate( AsmExpr * ) { GuardValue( skip ); skip = Skip; }
81	void premutate( ApplicationExpr * ) { GuardValue( skip ); skip = (skip == Skip) ? SkipInProgress : NoSkip; }
82
83
84	Expression * postmutate( ApplicationExpr * appExpr );
85	void premutate( FunctionDecl * funcDecl );
86	bool inIntrinsic = false;
87	};
88
89	/// Replace reference types with pointer types
90	struct ReferenceTypeElimination final {
91	Type * postmutate( ReferenceType * refType );
92	};
93
94	/// GCC-like Generalized Lvalues (which have since been removed from GCC)
95	/// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
96	/// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
97	struct GeneralizedLvalue final : public WithVisitorRef<GeneralizedLvalue> {
98	Expression * postmutate( AddressExpr * addressExpr );
99	Expression * postmutate( MemberExpr * memExpr );
100
101	template<typename Func>
102	Expression * applyTransformation( Expression * expr, Expression * arg, Func mkExpr );
103	};
104
105	/// Removes redundant &/& pattern that this pass can generate
106	struct CollapseAddrDeref final {
107	Expression * postmutate( AddressExpr * addressExpr );
108	Expression * postmutate( ApplicationExpr * appExpr );
109	};
110
111	struct AddrRef final : public WithGuards, public WithVisitorRef<AddrRef>, public WithShortCircuiting {
112	void premutate( AddressExpr * addrExpr );
113	Expression * postmutate( AddressExpr * addrExpr );
114	void premutate( Expression * expr );
115	void premutate( ApplicationExpr * appExpr );
116	void premutate( SingleInit * init );
117
118	void handleNonAddr( Expression * );
119
120	bool first = true;
121	bool current = false;
122	int refDepth = 0;
123	bool addCast = false;
124	};
125	} // namespace
126
127	static bool referencesEliminated = false;
128	// used by UntypedExpr::createDeref to determine whether result type of dereference should be ReferenceType or value type.
129	bool referencesPermissable() {
130	return ! referencesEliminated;
131	}
132
133	void convertLvalue( std::list< Declaration* > & translationUnit ) {
134	PassVisitor<ReferenceConversions> refCvt;
135	PassVisitor<ReferenceTypeElimination> elim;
136	PassVisitor<GeneralizedLvalue> genLval;
137	PassVisitor<FixIntrinsicArgs> fixer;
138	PassVisitor<CollapseAddrDeref> collapser;
139	PassVisitor<AddrRef> addrRef;
140	PassVisitor<FixIntrinsicResult> intrinsicResults;
141	mutateAll( translationUnit, intrinsicResults );
142	mutateAll( translationUnit, addrRef );
143	mutateAll( translationUnit, refCvt );
144	mutateAll( translationUnit, fixer );
145	mutateAll( translationUnit, collapser );
146	mutateAll( translationUnit, genLval );
147	mutateAll( translationUnit, elim ); // last because other passes need reference types to work
148
149	// from this point forward, no other pass should create reference types.
150	referencesEliminated = true;
151	}
152
153	Expression * generalizedLvalue( Expression * expr ) {
154	PassVisitor<GeneralizedLvalue> genLval;
155	return expr->acceptMutator( genLval );
156	}
157
158	namespace {
159	// true for intrinsic function calls that return an lvalue in C
160	bool isIntrinsicReference( Expression * expr ) {
161	// known intrinsic-reference prelude functions
162	static std::set<std::string> lvalueFunctions = { "*?", "?[?]" };
163	if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
164	std::string fname = InitTweak::getFunctionName( untyped );
165	return lvalueFunctions.count(fname);
166	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
167	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
168	return func->linkage == LinkageSpec::Intrinsic && lvalueFunctions.count(func->name);
169	}
170	}
171	return false;
172	}
173
174	Expression * FixIntrinsicResult::postmutate( ApplicationExpr * appExpr ) {
175	if ( skip != SkipInProgress && isIntrinsicReference( appExpr ) ) {
176	// eliminate reference types from intrinsic applications - now they return lvalues
177	ReferenceType * result = strict_dynamic_cast< ReferenceType * >( appExpr->result );
178	appExpr->result = result->base->clone();
179	if ( ! inIntrinsic ) {
180	// when not in an intrinsic function, add a cast to
181	// don't add cast when in an intrinsic function, since they already have the cast
182	Expression * ret = new CastExpr( appExpr, result );
183	std::swap( ret->env, appExpr->env );
184	return ret;
185	}
186	delete result;
187	}
188	return appExpr;
189	}
190
191	void FixIntrinsicResult::premutate( FunctionDecl * funcDecl ) {
192	GuardValue( inIntrinsic );
193	inIntrinsic = funcDecl->linkage == LinkageSpec::Intrinsic;
194	}
195
196	Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
197	// intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
198	if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
199	FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
200	assertf( ftype, "Function declaration does not have function type." );
201	// can be of differing lengths only when function is variadic
202	assertf( ftype->parameters.size() == appExpr->args.size() \|\| ftype->isVarArgs, "ApplicationExpr args do not match formal parameter type." );
203
204
205	unsigned int i = 0;
206	const unsigned int end = ftype->parameters.size();
207
208	/// The for loop may eagerly dereference the iterators and fail on empty lists
209	if(i == end) { return appExpr; }
210	for ( auto p : unsafe_group_iterate( appExpr->args, ftype->parameters ) ) {
211	Expression *& arg = std::get<0>( p );
212	Type * formal = std::get<1>( p )->get_type();
213	PRINT(
214	std::cerr << "pair<0>: " << arg << std::endl;
215	std::cerr << " -- " << arg->result << std::endl;
216	std::cerr << "pair<1>: " << formal << std::endl;
217	)
218	if ( dynamic_cast<ReferenceType*>( formal ) ) {
219	PRINT(
220	std::cerr << "===formal is reference" << std::endl;
221	)
222	// TODO: it's likely that the second condition should be ... && ! isIntrinsicReference( arg ), but this requires investigation.
223
224	if ( function->linkage != LinkageSpec::Intrinsic && isIntrinsicReference( arg ) ) {
225	// needed for definition of prelude functions, etc.
226	// if argument is dereference or array subscript, the result isn't REALLY a reference, but non-intrinsic functions expect a reference: take address
227
228	// NOTE: previously, this condition fixed
229	// void f(int *&);
230	// int & x = ...;
231	// f(&x);
232	// But now this is taken care of by a reference cast added by AddrRef. Need to find a new
233	// example or remove this branch.
234
235	PRINT(
236	std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
237	)
238	arg = new AddressExpr( arg );
239	// } else if ( function->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getPointerBase( arg->result ) ) {
240	} else if ( function->linkage == LinkageSpec::Intrinsic && arg->result->referenceDepth() != 0 ) {
241	// argument is a 'real' reference, but function expects a C lvalue: add a dereference to the reference-typed argument
242	PRINT(
243	std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
244	)
245	Type * baseType = InitTweak::getPointerBase( arg->result );
246	assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
247	PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
248	delete arg->result;
249	arg->result = ptrType;
250	arg = mkDeref( arg );
251	// assertf( arg->result->referenceDepth() == 0, "Reference types should have been eliminated from intrinsic function calls, but weren't: %s", toCString( arg->result ) );
252	}
253	}
254	++i;
255	if (i == end) break;
256	}
257	}
258	return appExpr;
259	}
260
261	// idea: &&&E: get outer &, inner &
262	// at inner &, record depth D of reference type of argument of &
263	// at outer &, add D derefs.
264	void AddrRef::handleNonAddr( Expression * ) {
265	// non-address-of: reset status variables:
266	// * current expr is NOT the first address-of expr in an address-of chain
267	// * next seen address-of expr IS the first in the chain.
268	GuardValue( current );
269	GuardValue( first );
270	current = false;
271	first = true;
272	}
273
274	void AddrRef::premutate( Expression * expr ) {
275	handleNonAddr( expr );
276	GuardValue( addCast );
277	addCast = false;
278	}
279
280	void AddrRef::premutate( AddressExpr * ) {
281	GuardValue( current );
282	GuardValue( first );
283	current = first; // is this the first address-of in the chain?
284	first = false; // from here out, no longer possible for next address-of to be first in chain
285	if ( current ) { // this is the outermost address-of in a chain
286	GuardValue( refDepth );
287	refDepth = 0; // set depth to 0 so that postmutate can find the innermost address-of easily
288	}
289	}
290
291	Expression * AddrRef::postmutate( AddressExpr * addrExpr ) {
292	PRINT( std::cerr << "addr ref at " << addrExpr << std::endl; )
293	if ( refDepth == 0 ) {
294	PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
295	// this is the innermost address-of in a chain, record depth D
296	if ( ! isIntrinsicReference( addrExpr->arg ) ) {
297	// try to avoid ?[?]
298	// 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.
299	refDepth = addrExpr->arg->result->referenceDepth();
300	PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
301	} else {
302	assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( addrExpr->arg ) );
303	}
304	}
305	if ( current ) { // this is the outermost address-of in a chain
306	PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
307	Expression * ret = addrExpr;
308	while ( refDepth ) {
309	// add one dereference for each
310	ret = mkDeref( ret );
311	refDepth--;
312	}
313
314	// if addrExpr depth is 0, then the result is a pointer because the arg was depth 1 and not lvalue.
315	// This means the dereference result is not a reference, is lvalue, and one less pointer depth than
316	// the addrExpr. Thus the cast is meaningless.
317	// TODO: One thing to double check is whether it is possible for the types to differ outside of the single
318	// pointer level (i.e. can the base type of addrExpr differ from the type of addrExpr-arg?).
319	// If so then the cast might need to be added, conditional on a more sophisticated check.
320	if ( addCast && addrExpr->result->referenceDepth() != 0 ) {
321	PRINT( std::cerr << "adding cast to " << addrExpr->result << std::endl; )
322	return new CastExpr( ret, addrExpr->result->clone() );
323	}
324	return ret;
325	}
326	PRINT( std::cerr << "not current..." << std::endl; )
327	return addrExpr;
328	}
329
330	void AddrRef::premutate( ApplicationExpr * appExpr ) {
331	visit_children = false;
332	GuardValue( addCast );
333	handleNonAddr( appExpr );
334	for ( Expression *& arg : appExpr->args ) {
335	// each argument with address-of requires a cast
336	addCast = true;
337	arg = arg->acceptMutator( *visitor );
338	}
339	}
340
341	void AddrRef::premutate( SingleInit * ) {
342	GuardValue( addCast );
343	// each initialization context with address-of requires a cast
344	addCast = true;
345	}
346
347
348	Expression * ReferenceConversions::postmutate( AddressExpr * addrExpr ) {
349	// Inner expression may have been lvalue to reference conversion, which becomes an address expression.
350	// In this case, remove the outer address expression and return the argument.
351	// TODO: It's possible that this might catch too much and require a more sophisticated check.
352	return addrExpr;
353	}
354
355	Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
356	// xxx - is it possible to convert directly between reference types with a different base? E.g.,
357	// int x;
358	// (double&)x;
359	// At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
360	// after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
361	// pointer casts in the right places.
362
363	// Note: reference depth difference is the determining factor in what code is run, rather than whether something is
364	// reference type or not, since conversion still needs to occur when both types are references that differ in depth.
365
366	Type * destType = castExpr->result;
367	Type * srcType = castExpr->arg->result;
368	assertf( destType, "Cast to no type in: %s", toCString( castExpr ) );
369	assertf( srcType, "Cast from no type in: %s", toCString( castExpr ) );
370	int depth1 = destType->referenceDepth();
371	int depth2 = srcType->referenceDepth();
372	int diff = depth1 - depth2;
373
374	if ( diff > 0 && ! castExpr->arg->get_lvalue() ) {
375	// rvalue to reference conversion -- introduce temporary
376	// know that reference depth of cast argument is 0, need to introduce n temporaries for reference depth of n, e.g.
377	// (int &&&)3;
378	// becomes
379	// int __ref_tmp_0 = 3;
380	// int & __ref_tmp_1 = _&_ref_tmp_0;
381	// int && __ref_tmp_2 = &__ref_tmp_1;
382	// &__ref_tmp_2;
383	// the last & comes from the remaining reference conversion code
384	SemanticWarning( castExpr->arg->location, Warning::RvalueToReferenceConversion, toCString( castExpr->arg ) );
385
386	static UniqueName tempNamer( "__ref_tmp_" );
387	ObjectDecl * temp = ObjectDecl::newObject( tempNamer.newName(), castExpr->arg->result->clone(), new SingleInit( castExpr->arg ) );
388	PRINT( std::cerr << "made temp: " << temp << std::endl; )
389	stmtsToAddBefore.push_back( new DeclStmt( temp ) );
390	for ( int i = 0; i < depth1-1; i++ ) { // xxx - maybe this should be diff-1? check how this works with reference type for srcType
391	ObjectDecl * newTemp = ObjectDecl::newObject( tempNamer.newName(), new ReferenceType( Type::Qualifiers(), temp->type->clone() ), new SingleInit( new AddressExpr( new VariableExpr( temp ) ) ) );
392	PRINT( std::cerr << "made temp" << i << ": " << newTemp << std::endl; )
393	stmtsToAddBefore.push_back( new DeclStmt( newTemp ) );
394	temp = newTemp;
395	}
396	// update diff so that remaining code works out correctly
397	castExpr->arg = new VariableExpr( temp );
398	PRINT( std::cerr << "update cast to: " << castExpr << std::endl; )
399	srcType = castExpr->arg->result;
400	depth2 = srcType->referenceDepth();
401	diff = depth1 - depth2;
402	assert( diff == 1 );
403	}
404
405	// handle conversion between different depths
406	PRINT (
407	if ( depth1 \|\| depth2 ) {
408	std::cerr << "destType: " << destType << " / srcType: " << srcType << std::endl;
409	std::cerr << "depth: " << depth1 << " / " << depth2 << std::endl;
410	}
411	)
412	if ( diff > 0 ) {
413	// conversion to type with more depth (e.g. int & -> int &&): add address-of for each level of difference
414	Expression * ret = castExpr->arg;
415	for ( int i = 0; i < diff; ++i ) {
416	ret = new AddressExpr( ret );
417	}
418	if ( castExpr->arg->get_lvalue() && ! ResolvExpr::typesCompatible( srcType, strict_dynamic_cast<ReferenceType *>( destType )->base, SymTab::Indexer() ) ) {
419	// must keep cast if cast-to type is different from the actual type
420	castExpr->arg = ret;
421	return castExpr;
422	}
423	ret->env = castExpr->env;
424	delete ret->result;
425	ret->result = castExpr->result;
426	castExpr->env = nullptr;
427	castExpr->arg = nullptr;
428	castExpr->result = nullptr;
429	delete castExpr;
430	return ret;
431	} else if ( diff < 0 ) {
432	// conversion to type with less depth (e.g. int && -> int &): add dereferences for each level of difference
433	diff = -diff; // care only about magnitude now
434	Expression * ret = castExpr->arg;
435	for ( int i = 0; i < diff; ++i ) {
436	ret = mkDeref( ret );
437	// xxx - try removing one reference here? actually, looks like mkDeref already does this, so more closely look at the types generated.
438	}
439	if ( ! ResolvExpr::typesCompatibleIgnoreQualifiers( destType->stripReferences(), srcType->stripReferences(), SymTab::Indexer() ) ) {
440	// must keep cast if types are different
441	castExpr->arg = ret;
442	return castExpr;
443	}
444	ret->env = castExpr->env;
445	delete ret->result;
446	ret->result = castExpr->result;
447	assert( ret->get_lvalue() ); // ensure result is lvalue
448	castExpr->env = nullptr;
449	castExpr->arg = nullptr;
450	castExpr->result = nullptr;
451	delete castExpr;
452	return ret;
453	} else {
454	assert( diff == 0 );
455	// conversion between references of the same depth
456	if ( ResolvExpr::typesCompatible( castExpr->result, castExpr->arg->result, SymTab::Indexer() ) && castExpr->isGenerated ) {
457	// Remove useless generated casts
458	PRINT(
459	std::cerr << "types are compatible, removing cast: " << castExpr << std::endl;
460	std::cerr << "-- " << castExpr->result << std::endl;
461	std::cerr << "-- " << castExpr->arg->result << std::endl;
462	)
463	Expression * ret = castExpr->arg;
464	castExpr->arg = nullptr;
465	std::swap( castExpr->env, ret->env );
466	delete castExpr;
467	return ret;
468	}
469	return castExpr;
470	}
471	}
472
473	Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
474	Type * base = refType->base;
475	Type::Qualifiers qualifiers = refType->get_qualifiers();
476	refType->base = nullptr;
477	delete refType;
478	return new PointerType( qualifiers, base );
479	}
480
481	template<typename Func>
482	Expression * GeneralizedLvalue::applyTransformation( Expression * expr, Expression * arg, Func mkExpr ) {
483	if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( arg ) ) {
484	Expression * arg1 = commaExpr->arg1->clone();
485	Expression * arg2 = commaExpr->arg2->clone();
486	Expression * ret = new CommaExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ) );
487	ret->env = expr->env;
488	expr->env = nullptr;
489	delete expr;
490	return ret;
491	} else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( arg ) ) {
492	Expression * arg1 = condExpr->arg1->clone();
493	Expression * arg2 = condExpr->arg2->clone();
494	Expression * arg3 = condExpr->arg3->clone();
495	ConditionalExpr * ret = new ConditionalExpr( arg1, mkExpr( arg2 )->acceptMutator( visitor ), mkExpr( arg3 )->acceptMutator( visitor ) );
496	ret->env = expr->env;
497	expr->env = nullptr;
498	delete expr;
499
500	// conditional expr type may not be either of the argument types, need to unify
501	using namespace ResolvExpr;
502	Type* commonType = nullptr;
503	TypeEnvironment newEnv;
504	AssertionSet needAssertions, haveAssertions;
505	OpenVarSet openVars;
506	unify( ret->arg2->result, ret->arg3->result, newEnv, needAssertions, haveAssertions, openVars, SymTab::Indexer(), commonType );
507	ret->result = commonType ? commonType : ret->arg2->result->clone();
508	return ret;
509	}
510	return expr;
511	}
512
513	Expression * GeneralizedLvalue::postmutate( MemberExpr * memExpr ) {
514	return applyTransformation( memExpr, memExpr->aggregate, [=]( Expression * aggr ) { return new MemberExpr( memExpr->member, aggr ); } );
515	}
516
517	Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
518	return applyTransformation( addrExpr, addrExpr->arg, []( Expression * arg ) { return new AddressExpr( arg ); } );
519	}
520
521	Expression * CollapseAddrDeref::postmutate( AddressExpr * addrExpr ) {
522	Expression * arg = addrExpr->arg;
523	if ( isIntrinsicReference( arg ) ) {
524	std::string fname = InitTweak::getFunctionName( arg );
525	if ( fname == "*?" ) {
526	Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
527	Expression * ret = arg0;
528	ret->set_env( addrExpr->env );
529	arg0 = nullptr;
530	addrExpr->env = nullptr;
531	delete addrExpr;
532	return ret;
533	}
534	} else if ( CastExpr * castExpr = dynamic_cast< CastExpr * > ( arg ) ) {
535	// need to move cast to pointer type out a level since address of pointer
536	// is not valid C code (can be introduced in prior passes, e.g., InstantiateGeneric)
537	if ( InitTweak::getPointerBase( castExpr->result ) ) {
538	addrExpr->arg = castExpr->arg;
539	castExpr->arg = addrExpr;
540	castExpr->result = new PointerType( Type::Qualifiers(), castExpr->result );
541	return castExpr;
542	}
543	}
544	return addrExpr;
545	}
546
547	Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
548	if ( isIntrinsicReference( appExpr ) ) {
549	std::string fname = InitTweak::getFunctionName( appExpr );
550	if ( fname == "*?" ) {
551	Expression * arg = InitTweak::getCallArg( appExpr, 0 );
552	// xxx - this isn't right, because it can remove casts that should be there...
553	// while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
554	// arg = castExpr->get_arg();
555	// }
556	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
557	Expression * ret = addrExpr->arg;
558	ret->env = appExpr->env;
559	addrExpr->arg = nullptr;
560	appExpr->env = nullptr;
561	delete appExpr;
562	return ret;
563	}
564	}
565	}
566	return appExpr;
567	}
568	} // namespace
569	} // namespace GenPoly
570
571	// Local Variables: //
572	// tab-width: 4 //
573	// mode: c++ //
574	// compile-command: "make install" //
575	// End: //

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