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source: src/GenPoly/Lvalue.cc @ 96ac72c

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

Last change on this file since 96ac72c was aaeacf4, checked in by Thierry Delisle <tdelisle@…>, 5 years ago
Removed global look-up table from UniqueId? to Decl
Property mode set to `100644`
File size: 23.3 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 "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	ret->result->set_lvalue( true );
57	return ret;
58	} else {
59	return UntypedExpr::createDeref( arg );
60	}
61	}
62
63	struct ReferenceConversions final : public WithStmtsToAdd {
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	Expression * postmutate( ApplicationExpr * appExpr );
75	void premutate( FunctionDecl * funcDecl );
76	bool inIntrinsic = false;
77	};
78
79	/// Replace reference types with pointer types
80	struct ReferenceTypeElimination final {
81	Type * postmutate( ReferenceType * refType );
82	};
83
84	/// GCC-like Generalized Lvalues (which have since been removed from GCC)
85	/// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
86	/// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
87	struct GeneralizedLvalue final : public WithVisitorRef<GeneralizedLvalue> {
88	Expression * postmutate( AddressExpr * addressExpr );
89	Expression * postmutate( MemberExpr * memExpr );
90
91	template<typename Func>
92	Expression * applyTransformation( Expression * expr, Expression * arg, Func mkExpr );
93	};
94
95	/// Removes redundant &/& pattern that this pass can generate
96	struct CollapseAddrDeref final {
97	Expression * postmutate( AddressExpr * addressExpr );
98	Expression * postmutate( ApplicationExpr * appExpr );
99	};
100
101	struct AddrRef final : public WithGuards, public WithVisitorRef<AddrRef>, public WithShortCircuiting {
102	void premutate( AddressExpr * addrExpr );
103	Expression * postmutate( AddressExpr * addrExpr );
104	void premutate( Expression * expr );
105	void premutate( ApplicationExpr * appExpr );
106	void premutate( SingleInit * init );
107
108	void handleNonAddr( Expression * );
109
110	bool first = true;
111	bool current = false;
112	int refDepth = 0;
113	bool addCast = false;
114	};
115	} // namespace
116
117	static bool referencesEliminated = false;
118	// used by UntypedExpr::createDeref to determine whether result type of dereference should be ReferenceType or value type.
119	bool referencesPermissable() {
120	return ! referencesEliminated;
121	}
122
123	void convertLvalue( std::list< Declaration* > & translationUnit ) {
124	PassVisitor<ReferenceConversions> refCvt;
125	PassVisitor<ReferenceTypeElimination> elim;
126	PassVisitor<GeneralizedLvalue> genLval;
127	PassVisitor<FixIntrinsicArgs> fixer;
128	PassVisitor<CollapseAddrDeref> collapser;
129	PassVisitor<AddrRef> addrRef;
130	PassVisitor<FixIntrinsicResult> intrinsicResults;
131	mutateAll( translationUnit, intrinsicResults );
132	mutateAll( translationUnit, addrRef );
133	mutateAll( translationUnit, refCvt );
134	mutateAll( translationUnit, fixer );
135	mutateAll( translationUnit, collapser );
136	mutateAll( translationUnit, genLval );
137	mutateAll( translationUnit, elim ); // last because other passes need reference types to work
138
139	// from this point forward, no other pass should create reference types.
140	referencesEliminated = true;
141	}
142
143	Expression * generalizedLvalue( Expression * expr ) {
144	PassVisitor<GeneralizedLvalue> genLval;
145	return expr->acceptMutator( genLval );
146	}
147
148	namespace {
149	// true for intrinsic function calls that return an lvalue in C
150	bool isIntrinsicReference( Expression * expr ) {
151	// known intrinsic-reference prelude functions
152	static std::set<std::string> lvalueFunctions = { "*?", "?[?]" };
153	if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
154	std::string fname = InitTweak::getFunctionName( untyped );
155	return lvalueFunctions.count(fname);
156	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
157	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
158	return func->linkage == LinkageSpec::Intrinsic && lvalueFunctions.count(func->name);
159	}
160	}
161	return false;
162	}
163
164	Expression * FixIntrinsicResult::postmutate( ApplicationExpr * appExpr ) {
165	if ( isIntrinsicReference( appExpr ) ) {
166	// eliminate reference types from intrinsic applications - now they return lvalues
167	ReferenceType * result = strict_dynamic_cast< ReferenceType * >( appExpr->result );
168	appExpr->result = result->base->clone();
169	appExpr->result->set_lvalue( true );
170	if ( ! inIntrinsic ) {
171	// when not in an intrinsic function, add a cast to
172	// don't add cast when in an intrinsic function, since they already have the cast
173	Expression * ret = new CastExpr( appExpr, result );
174	std::swap( ret->env, appExpr->env );
175	return ret;
176	}
177	delete result;
178	}
179	return appExpr;
180	}
181
182	void FixIntrinsicResult::premutate( FunctionDecl * funcDecl ) {
183	GuardValue( inIntrinsic );
184	inIntrinsic = funcDecl->linkage == LinkageSpec::Intrinsic;
185	}
186
187	Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
188	// intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
189	if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
190	FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
191	assertf( ftype, "Function declaration does not have function type." );
192	// can be of differing lengths only when function is variadic
193	assertf( ftype->parameters.size() == appExpr->args.size() \|\| ftype->isVarArgs, "ApplicationExpr args do not match formal parameter type." );
194
195
196	unsigned int i = 0;
197	const unsigned int end = ftype->parameters.size();
198
199	/// The for loop may eagerly dereference the iterators and fail on empty lists
200	if(i == end) { return appExpr; }
201	for ( auto p : unsafe_group_iterate( appExpr->args, ftype->parameters ) ) {
202	Expression *& arg = std::get<0>( p );
203	Type * formal = std::get<1>( p )->get_type();
204	PRINT(
205	std::cerr << "pair<0>: " << arg << std::endl;
206	std::cerr << " -- " << arg->result << std::endl;
207	std::cerr << "pair<1>: " << formal << std::endl;
208	)
209	if ( dynamic_cast<ReferenceType*>( formal ) ) {
210	PRINT(
211	std::cerr << "===formal is reference" << std::endl;
212	)
213	// TODO: it's likely that the second condition should be ... && ! isIntrinsicReference( arg ), but this requires investigation.
214
215	if ( function->linkage != LinkageSpec::Intrinsic && isIntrinsicReference( arg ) ) {
216	// needed for definition of prelude functions, etc.
217	// if argument is dereference or array subscript, the result isn't REALLY a reference, but non-intrinsic functions expect a reference: take address
218
219	// NOTE: previously, this condition fixed
220	// void f(int *&);
221	// int & x = ...;
222	// f(&x);
223	// But now this is taken care of by a reference cast added by AddrRef. Need to find a new
224	// example or remove this branch.
225
226	PRINT(
227	std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
228	)
229	arg = new AddressExpr( arg );
230	// } else if ( function->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getPointerBase( arg->result ) ) {
231	} else if ( function->linkage == LinkageSpec::Intrinsic && arg->result->referenceDepth() != 0 ) {
232	// argument is a 'real' reference, but function expects a C lvalue: add a dereference to the reference-typed argument
233	PRINT(
234	std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
235	)
236	Type * baseType = InitTweak::getPointerBase( arg->result );
237	assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
238	PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
239	delete arg->result;
240	arg->result = ptrType;
241	arg = mkDeref( arg );
242	// assertf( arg->result->referenceDepth() == 0, "Reference types should have been eliminated from intrinsic function calls, but weren't: %s", toCString( arg->result ) );
243	}
244	}
245	++i;
246	if (i == end) break;
247	}
248	}
249	return appExpr;
250	}
251
252	// idea: &&&E: get outer &, inner &
253	// at inner &, record depth D of reference type of argument of &
254	// at outer &, add D derefs.
255	void AddrRef::handleNonAddr( Expression * ) {
256	// non-address-of: reset status variables:
257	// * current expr is NOT the first address-of expr in an address-of chain
258	// * next seen address-of expr IS the first in the chain.
259	GuardValue( current );
260	GuardValue( first );
261	current = false;
262	first = true;
263	}
264
265	void AddrRef::premutate( Expression * expr ) {
266	handleNonAddr( expr );
267	GuardValue( addCast );
268	addCast = false;
269	}
270
271	void AddrRef::premutate( AddressExpr * ) {
272	GuardValue( current );
273	GuardValue( first );
274	current = first; // is this the first address-of in the chain?
275	first = false; // from here out, no longer possible for next address-of to be first in chain
276	if ( current ) { // this is the outermost address-of in a chain
277	GuardValue( refDepth );
278	refDepth = 0; // set depth to 0 so that postmutate can find the innermost address-of easily
279	}
280	}
281
282	Expression * AddrRef::postmutate( AddressExpr * addrExpr ) {
283	PRINT( std::cerr << "addr ref at " << addrExpr << std::endl; )
284	if ( refDepth == 0 ) {
285	PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
286	// this is the innermost address-of in a chain, record depth D
287	if ( ! isIntrinsicReference( addrExpr->arg ) ) {
288	// try to avoid ?[?]
289	// 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.
290	refDepth = addrExpr->arg->result->referenceDepth();
291	PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
292	} else {
293	assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( addrExpr->arg ) );
294	}
295	}
296	if ( current ) { // this is the outermost address-of in a chain
297	PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
298	Expression * ret = addrExpr;
299	while ( refDepth ) {
300	// add one dereference for each
301	ret = mkDeref( ret );
302	refDepth--;
303	}
304
305	// if addrExpr depth is 0, then the result is a pointer because the arg was depth 1 and not lvalue.
306	// This means the dereference result is not a reference, is lvalue, and one less pointer depth than
307	// the addrExpr. Thus the cast is meaningless.
308	// TODO: One thing to double check is whether it is possible for the types to differ outside of the single
309	// pointer level (i.e. can the base type of addrExpr differ from the type of addrExpr-arg?).
310	// If so then the cast might need to be added, conditional on a more sophisticated check.
311	if ( addCast && addrExpr->result->referenceDepth() != 0 ) {
312	PRINT( std::cerr << "adding cast to " << addrExpr->result << std::endl; )
313	return new CastExpr( ret, addrExpr->result->clone() );
314	}
315	return ret;
316	}
317	PRINT( std::cerr << "not current..." << std::endl; )
318	return addrExpr;
319	}
320
321	void AddrRef::premutate( ApplicationExpr * appExpr ) {
322	visit_children = false;
323	GuardValue( addCast );
324	handleNonAddr( appExpr );
325	for ( Expression *& arg : appExpr->args ) {
326	// each argument with address-of requires a cast
327	addCast = true;
328	arg = arg->acceptMutator( *visitor );
329	}
330	}
331
332	void AddrRef::premutate( SingleInit * ) {
333	GuardValue( addCast );
334	// each initialization context with address-of requires a cast
335	addCast = true;
336	}
337
338
339	Expression * ReferenceConversions::postmutate( AddressExpr * addrExpr ) {
340	// Inner expression may have been lvalue to reference conversion, which becomes an address expression.
341	// In this case, remove the outer address expression and return the argument.
342	// TODO: It's possible that this might catch too much and require a more sophisticated check.
343	return addrExpr;
344	}
345
346	Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
347	// xxx - is it possible to convert directly between reference types with a different base? E.g.,
348	// int x;
349	// (double&)x;
350	// At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
351	// after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
352	// pointer casts in the right places.
353
354	// Note: reference depth difference is the determining factor in what code is run, rather than whether something is
355	// reference type or not, since conversion still needs to occur when both types are references that differ in depth.
356
357	Type * destType = castExpr->result;
358	Type * srcType = castExpr->arg->result;
359	assertf( destType, "Cast to no type in: %s", toCString( castExpr ) );
360	assertf( srcType, "Cast from no type in: %s", toCString( castExpr ) );
361	int depth1 = destType->referenceDepth();
362	int depth2 = srcType->referenceDepth();
363	int diff = depth1 - depth2;
364
365	if ( diff > 0 && ! srcType->get_lvalue() ) {
366	// rvalue to reference conversion -- introduce temporary
367	// know that reference depth of cast argument is 0, need to introduce n temporaries for reference depth of n, e.g.
368	// (int &&&)3;
369	// becomes
370	// int __ref_tmp_0 = 3;
371	// int & __ref_tmp_1 = _&_ref_tmp_0;
372	// int && __ref_tmp_2 = &__ref_tmp_1;
373	// &__ref_tmp_2;
374	// the last & comes from the remaining reference conversion code
375	SemanticWarning( castExpr->arg->location, Warning::RvalueToReferenceConversion, toCString( castExpr->arg ) );
376
377	static UniqueName tempNamer( "__ref_tmp_" );
378	ObjectDecl * temp = ObjectDecl::newObject( tempNamer.newName(), castExpr->arg->result->clone(), new SingleInit( castExpr->arg ) );
379	PRINT( std::cerr << "made temp: " << temp << std::endl; )
380	stmtsToAddBefore.push_back( new DeclStmt( temp ) );
381	for ( int i = 0; i < depth1-1; i++ ) { // xxx - maybe this should be diff-1? check how this works with reference type for srcType
382	ObjectDecl * newTemp = ObjectDecl::newObject( tempNamer.newName(), new ReferenceType( Type::Qualifiers(), temp->type->clone() ), new SingleInit( new AddressExpr( new VariableExpr( temp ) ) ) );
383	PRINT( std::cerr << "made temp" << i << ": " << newTemp << std::endl; )
384	stmtsToAddBefore.push_back( new DeclStmt( newTemp ) );
385	temp = newTemp;
386	}
387	// update diff so that remaining code works out correctly
388	castExpr->arg = new VariableExpr( temp );
389	PRINT( std::cerr << "update cast to: " << castExpr << std::endl; )
390	srcType = castExpr->arg->result;
391	depth2 = srcType->referenceDepth();
392	diff = depth1 - depth2;
393	assert( diff == 1 );
394	}
395
396	// handle conversion between different depths
397	PRINT (
398	if ( depth1 \|\| depth2 ) {
399	std::cerr << "destType: " << destType << " / srcType: " << srcType << std::endl;
400	std::cerr << "depth: " << depth1 << " / " << depth2 << std::endl;
401	}
402	)
403	if ( diff > 0 ) {
404	// conversion to type with more depth (e.g. int & -> int &&): add address-of for each level of difference
405	Expression * ret = castExpr->arg;
406	for ( int i = 0; i < diff; ++i ) {
407	ret = new AddressExpr( ret );
408	}
409	if ( srcType->get_lvalue() && ! ResolvExpr::typesCompatible( srcType, strict_dynamic_cast<ReferenceType *>( destType )->base, SymTab::Indexer() ) ) {
410	// must keep cast if cast-to type is different from the actual type
411	castExpr->arg = ret;
412	return castExpr;
413	}
414	ret->env = castExpr->env;
415	delete ret->result;
416	ret->result = castExpr->result;
417	castExpr->env = nullptr;
418	castExpr->arg = nullptr;
419	castExpr->result = nullptr;
420	delete castExpr;
421	return ret;
422	} else if ( diff < 0 ) {
423	// conversion to type with less depth (e.g. int && -> int &): add dereferences for each level of difference
424	diff = -diff; // care only about magnitude now
425	Expression * ret = castExpr->arg;
426	for ( int i = 0; i < diff; ++i ) {
427	ret = mkDeref( ret );
428	// xxx - try removing one reference here? actually, looks like mkDeref already does this, so more closely look at the types generated.
429	}
430	if ( ! ResolvExpr::typesCompatibleIgnoreQualifiers( destType->stripReferences(), srcType->stripReferences(), SymTab::Indexer() ) ) {
431	// must keep cast if types are different
432	castExpr->arg = ret;
433	return castExpr;
434	}
435	ret->env = castExpr->env;
436	delete ret->result;
437	ret->result = castExpr->result;
438	ret->result->set_lvalue( true ); // ensure result is lvalue
439	castExpr->env = nullptr;
440	castExpr->arg = nullptr;
441	castExpr->result = nullptr;
442	delete castExpr;
443	return ret;
444	} else {
445	assert( diff == 0 );
446	// conversion between references of the same depth
447	if ( ResolvExpr::typesCompatible( castExpr->result, castExpr->arg->result, SymTab::Indexer() ) && castExpr->isGenerated ) {
448	// Remove useless generated casts
449	PRINT(
450	std::cerr << "types are compatible, removing cast: " << castExpr << std::endl;
451	std::cerr << "-- " << castExpr->result << std::endl;
452	std::cerr << "-- " << castExpr->arg->result << std::endl;
453	)
454	Expression * ret = castExpr->arg;
455	castExpr->arg = nullptr;
456	std::swap( castExpr->env, ret->env );
457	delete castExpr;
458	return ret;
459	}
460	return castExpr;
461	}
462	}
463
464	Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
465	Type * base = refType->base;
466	Type::Qualifiers qualifiers = refType->get_qualifiers();
467	refType->base = nullptr;
468	delete refType;
469	return new PointerType( qualifiers, base );
470	}
471
472	template<typename Func>
473	Expression * GeneralizedLvalue::applyTransformation( Expression * expr, Expression * arg, Func mkExpr ) {
474	if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( arg ) ) {
475	Expression * arg1 = commaExpr->arg1->clone();
476	Expression * arg2 = commaExpr->arg2->clone();
477	Expression * ret = new CommaExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ) );
478	ret->env = expr->env;
479	expr->env = nullptr;
480	delete expr;
481	return ret;
482	} else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( arg ) ) {
483	Expression * arg1 = condExpr->arg1->clone();
484	Expression * arg2 = condExpr->arg2->clone();
485	Expression * arg3 = condExpr->arg3->clone();
486	ConditionalExpr * ret = new ConditionalExpr( arg1, mkExpr( arg2 )->acceptMutator( visitor ), mkExpr( arg3 )->acceptMutator( visitor ) );
487	ret->env = expr->env;
488	expr->env = nullptr;
489	delete expr;
490
491	// conditional expr type may not be either of the argument types, need to unify
492	using namespace ResolvExpr;
493	Type* commonType = nullptr;
494	TypeEnvironment newEnv;
495	AssertionSet needAssertions, haveAssertions;
496	OpenVarSet openVars;
497	unify( ret->arg2->result, ret->arg3->result, newEnv, needAssertions, haveAssertions, openVars, SymTab::Indexer(), commonType );
498	ret->result = commonType ? commonType : ret->arg2->result->clone();
499	return ret;
500	}
501	return expr;
502	}
503
504	Expression * GeneralizedLvalue::postmutate( MemberExpr * memExpr ) {
505	return applyTransformation( memExpr, memExpr->aggregate, [=]( Expression * aggr ) { return new MemberExpr( memExpr->member, aggr ); } );
506	}
507
508	Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
509	return applyTransformation( addrExpr, addrExpr->arg, []( Expression * arg ) { return new AddressExpr( arg ); } );
510	}
511
512	Expression * CollapseAddrDeref::postmutate( AddressExpr * addrExpr ) {
513	Expression * arg = addrExpr->arg;
514	if ( isIntrinsicReference( arg ) ) {
515	std::string fname = InitTweak::getFunctionName( arg );
516	if ( fname == "*?" ) {
517	Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
518	Expression * ret = arg0;
519	ret->set_env( addrExpr->env );
520	arg0 = nullptr;
521	addrExpr->env = nullptr;
522	delete addrExpr;
523	return ret;
524	}
525	} else if ( CastExpr * castExpr = dynamic_cast< CastExpr * > ( arg ) ) {
526	// need to move cast to pointer type out a level since address of pointer
527	// is not valid C code (can be introduced in prior passes, e.g., InstantiateGeneric)
528	if ( InitTweak::getPointerBase( castExpr->result ) ) {
529	addrExpr->arg = castExpr->arg;
530	castExpr->arg = addrExpr;
531	castExpr->result = new PointerType( Type::Qualifiers(), castExpr->result );
532	return castExpr;
533	}
534	}
535	return addrExpr;
536	}
537
538	Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
539	if ( isIntrinsicReference( appExpr ) ) {
540	std::string fname = InitTweak::getFunctionName( appExpr );
541	if ( fname == "*?" ) {
542	Expression * arg = InitTweak::getCallArg( appExpr, 0 );
543	// xxx - this isn't right, because it can remove casts that should be there...
544	// while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
545	// arg = castExpr->get_arg();
546	// }
547	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
548	Expression * ret = addrExpr->arg;
549	ret->env = appExpr->env;
550	addrExpr->arg = nullptr;
551	appExpr->env = nullptr;
552	delete appExpr;
553	return ret;
554	}
555	}
556	}
557	return appExpr;
558	}
559	} // namespace
560	} // namespace GenPoly
561
562	// Local Variables: //
563	// tab-width: 4 //
564	// mode: c++ //
565	// compile-command: "make install" //
566	// End: //

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