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source: src/GenPoly/Lvalue.cc @ c7616dd

Last change on this file since c7616dd was 9feb34b, checked in by Andrew Beach <ajbeach@…>, 19 months 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

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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 : 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
45	namespace 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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