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source: src/GenPoly/Lvalue.cc @ 427854b

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

Last change on this file since 427854b was 427854b, checked in by Thierry Delisle <tdelisle@…>, 4 years ago
First draft implementation of generators, still missing error checking, testing and clean-up
Property mode set to `100644`
File size: 23.8 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	translationUnit.back()->print( std::cout );
143	mutateAll( translationUnit, addrRef );
144	translationUnit.back()->print( std::cout );
145	mutateAll( translationUnit, refCvt );
146	translationUnit.back()->print( std::cout );
147	mutateAll( translationUnit, fixer );
148	translationUnit.back()->print( std::cout );
149	mutateAll( translationUnit, collapser );
150	translationUnit.back()->print( std::cout );
151	mutateAll( translationUnit, genLval );
152	translationUnit.back()->print( std::cout );
153	mutateAll( translationUnit, elim ); // last because other passes need reference types to work
154
155	// from this point forward, no other pass should create reference types.
156	referencesEliminated = true;
157	}
158
159	Expression * generalizedLvalue( Expression * expr ) {
160	PassVisitor<GeneralizedLvalue> genLval;
161	return expr->acceptMutator( genLval );
162	}
163
164	namespace {
165	// true for intrinsic function calls that return an lvalue in C
166	bool isIntrinsicReference( Expression * expr ) {
167	// known intrinsic-reference prelude functions
168	static std::set<std::string> lvalueFunctions = { "*?", "?[?]" };
169	if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
170	std::string fname = InitTweak::getFunctionName( untyped );
171	return lvalueFunctions.count(fname);
172	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
173	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
174	return func->linkage == LinkageSpec::Intrinsic && lvalueFunctions.count(func->name);
175	}
176	}
177	return false;
178	}
179
180	Expression * FixIntrinsicResult::postmutate( ApplicationExpr * appExpr ) {
181	if ( skip != SkipInProgress && isIntrinsicReference( appExpr ) ) {
182	// eliminate reference types from intrinsic applications - now they return lvalues
183	ReferenceType * result = strict_dynamic_cast< ReferenceType * >( appExpr->result );
184	appExpr->result = result->base->clone();
185	if ( ! inIntrinsic ) {
186	// when not in an intrinsic function, add a cast to
187	// don't add cast when in an intrinsic function, since they already have the cast
188	Expression * ret = new CastExpr( appExpr, result );
189	std::swap( ret->env, appExpr->env );
190	return ret;
191	}
192	delete result;
193	}
194	return appExpr;
195	}
196
197	void FixIntrinsicResult::premutate( FunctionDecl * funcDecl ) {
198	GuardValue( inIntrinsic );
199	inIntrinsic = funcDecl->linkage == LinkageSpec::Intrinsic;
200	}
201
202	Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
203	// intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
204	if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
205	FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
206	assertf( ftype, "Function declaration does not have function type." );
207	// can be of differing lengths only when function is variadic
208	assertf( ftype->parameters.size() == appExpr->args.size() \|\| ftype->isVarArgs, "ApplicationExpr args do not match formal parameter type." );
209
210
211	unsigned int i = 0;
212	const unsigned int end = ftype->parameters.size();
213
214	/// The for loop may eagerly dereference the iterators and fail on empty lists
215	if(i == end) { return appExpr; }
216	for ( auto p : unsafe_group_iterate( appExpr->args, ftype->parameters ) ) {
217	Expression *& arg = std::get<0>( p );
218	Type * formal = std::get<1>( p )->get_type();
219	PRINT(
220	std::cerr << "pair<0>: " << arg << std::endl;
221	std::cerr << " -- " << arg->result << std::endl;
222	std::cerr << "pair<1>: " << formal << std::endl;
223	)
224	if ( dynamic_cast<ReferenceType*>( formal ) ) {
225	PRINT(
226	std::cerr << "===formal is reference" << std::endl;
227	)
228	// TODO: it's likely that the second condition should be ... && ! isIntrinsicReference( arg ), but this requires investigation.
229
230	if ( function->linkage != LinkageSpec::Intrinsic && isIntrinsicReference( arg ) ) {
231	// needed for definition of prelude functions, etc.
232	// if argument is dereference or array subscript, the result isn't REALLY a reference, but non-intrinsic functions expect a reference: take address
233
234	// NOTE: previously, this condition fixed
235	// void f(int *&);
236	// int & x = ...;
237	// f(&x);
238	// But now this is taken care of by a reference cast added by AddrRef. Need to find a new
239	// example or remove this branch.
240
241	PRINT(
242	std::cerr << "===is intrinsic arg in non-intrinsic call - adding address" << std::endl;
243	)
244	arg = new AddressExpr( arg );
245	// } else if ( function->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getPointerBase( arg->result ) ) {
246	} else if ( function->linkage == LinkageSpec::Intrinsic && arg->result->referenceDepth() != 0 ) {
247	// argument is a 'real' reference, but function expects a C lvalue: add a dereference to the reference-typed argument
248	PRINT(
249	std::cerr << "===is non-intrinsic arg in intrinsic call - adding deref to arg" << std::endl;
250	)
251	Type * baseType = InitTweak::getPointerBase( arg->result );
252	assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->result ).c_str() );
253	PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
254	delete arg->result;
255	arg->result = ptrType;
256	arg = mkDeref( arg );
257	// assertf( arg->result->referenceDepth() == 0, "Reference types should have been eliminated from intrinsic function calls, but weren't: %s", toCString( arg->result ) );
258	}
259	}
260	++i;
261	if (i == end) break;
262	}
263	}
264	return appExpr;
265	}
266
267	// idea: &&&E: get outer &, inner &
268	// at inner &, record depth D of reference type of argument of &
269	// at outer &, add D derefs.
270	void AddrRef::handleNonAddr( Expression * ) {
271	// non-address-of: reset status variables:
272	// * current expr is NOT the first address-of expr in an address-of chain
273	// * next seen address-of expr IS the first in the chain.
274	GuardValue( current );
275	GuardValue( first );
276	current = false;
277	first = true;
278	}
279
280	void AddrRef::premutate( Expression * expr ) {
281	handleNonAddr( expr );
282	GuardValue( addCast );
283	addCast = false;
284	}
285
286	void AddrRef::premutate( AddressExpr * ) {
287	GuardValue( current );
288	GuardValue( first );
289	current = first; // is this the first address-of in the chain?
290	first = false; // from here out, no longer possible for next address-of to be first in chain
291	if ( current ) { // this is the outermost address-of in a chain
292	GuardValue( refDepth );
293	refDepth = 0; // set depth to 0 so that postmutate can find the innermost address-of easily
294	}
295	}
296
297	Expression * AddrRef::postmutate( AddressExpr * addrExpr ) {
298	PRINT( std::cerr << "addr ref at " << addrExpr << std::endl; )
299	if ( refDepth == 0 ) {
300	PRINT( std::cerr << "depth 0, get new depth..." << std::endl; )
301	// this is the innermost address-of in a chain, record depth D
302	if ( ! isIntrinsicReference( addrExpr->arg ) ) {
303	// try to avoid ?[?]
304	// 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.
305	refDepth = addrExpr->arg->result->referenceDepth();
306	PRINT( std::cerr << "arg not intrinsic reference, new depth is: " << refDepth << std::endl; )
307	} else {
308	assertf( false, "AddrRef : address-of should not have intrinsic reference argument: %s", toCString( addrExpr->arg ) );
309	}
310	}
311	if ( current ) { // this is the outermost address-of in a chain
312	PRINT( std::cerr << "current, depth is: " << refDepth << std::endl; )
313	Expression * ret = addrExpr;
314	while ( refDepth ) {
315	// add one dereference for each
316	ret = mkDeref( ret );
317	refDepth--;
318	}
319
320	// if addrExpr depth is 0, then the result is a pointer because the arg was depth 1 and not lvalue.
321	// This means the dereference result is not a reference, is lvalue, and one less pointer depth than
322	// the addrExpr. Thus the cast is meaningless.
323	// TODO: One thing to double check is whether it is possible for the types to differ outside of the single
324	// pointer level (i.e. can the base type of addrExpr differ from the type of addrExpr-arg?).
325	// If so then the cast might need to be added, conditional on a more sophisticated check.
326	if ( addCast && addrExpr->result->referenceDepth() != 0 ) {
327	PRINT( std::cerr << "adding cast to " << addrExpr->result << std::endl; )
328	return new CastExpr( ret, addrExpr->result->clone() );
329	}
330	return ret;
331	}
332	PRINT( std::cerr << "not current..." << std::endl; )
333	return addrExpr;
334	}
335
336	void AddrRef::premutate( ApplicationExpr * appExpr ) {
337	visit_children = false;
338	GuardValue( addCast );
339	handleNonAddr( appExpr );
340	for ( Expression *& arg : appExpr->args ) {
341	// each argument with address-of requires a cast
342	addCast = true;
343	arg = arg->acceptMutator( *visitor );
344	}
345	}
346
347	void AddrRef::premutate( SingleInit * ) {
348	GuardValue( addCast );
349	// each initialization context with address-of requires a cast
350	addCast = true;
351	}
352
353
354	Expression * ReferenceConversions::postmutate( AddressExpr * addrExpr ) {
355	// Inner expression may have been lvalue to reference conversion, which becomes an address expression.
356	// In this case, remove the outer address expression and return the argument.
357	// TODO: It's possible that this might catch too much and require a more sophisticated check.
358	return addrExpr;
359	}
360
361	Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
362	// xxx - is it possible to convert directly between reference types with a different base? E.g.,
363	// int x;
364	// (double&)x;
365	// At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
366	// after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
367	// pointer casts in the right places.
368
369	// Note: reference depth difference is the determining factor in what code is run, rather than whether something is
370	// reference type or not, since conversion still needs to occur when both types are references that differ in depth.
371
372	Type * destType = castExpr->result;
373	Type * srcType = castExpr->arg->result;
374	assertf( destType, "Cast to no type in: %s", toCString( castExpr ) );
375	assertf( srcType, "Cast from no type in: %s", toCString( castExpr ) );
376	int depth1 = destType->referenceDepth();
377	int depth2 = srcType->referenceDepth();
378	int diff = depth1 - depth2;
379
380	if ( diff > 0 && ! castExpr->arg->get_lvalue() ) {
381	// rvalue to reference conversion -- introduce temporary
382	// know that reference depth of cast argument is 0, need to introduce n temporaries for reference depth of n, e.g.
383	// (int &&&)3;
384	// becomes
385	// int __ref_tmp_0 = 3;
386	// int & __ref_tmp_1 = _&_ref_tmp_0;
387	// int && __ref_tmp_2 = &__ref_tmp_1;
388	// &__ref_tmp_2;
389	// the last & comes from the remaining reference conversion code
390	SemanticWarning( castExpr->arg->location, Warning::RvalueToReferenceConversion, toCString( castExpr->arg ) );
391
392	static UniqueName tempNamer( "__ref_tmp_" );
393	ObjectDecl * temp = ObjectDecl::newObject( tempNamer.newName(), castExpr->arg->result->clone(), new SingleInit( castExpr->arg ) );
394	PRINT( std::cerr << "made temp: " << temp << std::endl; )
395	stmtsToAddBefore.push_back( new DeclStmt( temp ) );
396	for ( int i = 0; i < depth1-1; i++ ) { // xxx - maybe this should be diff-1? check how this works with reference type for srcType
397	ObjectDecl * newTemp = ObjectDecl::newObject( tempNamer.newName(), new ReferenceType( Type::Qualifiers(), temp->type->clone() ), new SingleInit( new AddressExpr( new VariableExpr( temp ) ) ) );
398	PRINT( std::cerr << "made temp" << i << ": " << newTemp << std::endl; )
399	stmtsToAddBefore.push_back( new DeclStmt( newTemp ) );
400	temp = newTemp;
401	}
402	// update diff so that remaining code works out correctly
403	castExpr->arg = new VariableExpr( temp );
404	PRINT( std::cerr << "update cast to: " << castExpr << std::endl; )
405	srcType = castExpr->arg->result;
406	depth2 = srcType->referenceDepth();
407	diff = depth1 - depth2;
408	assert( diff == 1 );
409	}
410
411	// handle conversion between different depths
412	PRINT (
413	if ( depth1 \|\| depth2 ) {
414	std::cerr << "destType: " << destType << " / srcType: " << srcType << std::endl;
415	std::cerr << "depth: " << depth1 << " / " << depth2 << std::endl;
416	}
417	)
418	if ( diff > 0 ) {
419	// conversion to type with more depth (e.g. int & -> int &&): add address-of for each level of difference
420	Expression * ret = castExpr->arg;
421	for ( int i = 0; i < diff; ++i ) {
422	ret = new AddressExpr( ret );
423	}
424	if ( castExpr->arg->get_lvalue() && ! ResolvExpr::typesCompatible( srcType, strict_dynamic_cast<ReferenceType *>( destType )->base, SymTab::Indexer() ) ) {
425	// must keep cast if cast-to type is different from the actual type
426	castExpr->arg = ret;
427	return castExpr;
428	}
429	ret->env = castExpr->env;
430	delete ret->result;
431	ret->result = castExpr->result;
432	castExpr->env = nullptr;
433	castExpr->arg = nullptr;
434	castExpr->result = nullptr;
435	delete castExpr;
436	return ret;
437	} else if ( diff < 0 ) {
438	// conversion to type with less depth (e.g. int && -> int &): add dereferences for each level of difference
439	diff = -diff; // care only about magnitude now
440	Expression * ret = castExpr->arg;
441	for ( int i = 0; i < diff; ++i ) {
442	ret = mkDeref( ret );
443	// xxx - try removing one reference here? actually, looks like mkDeref already does this, so more closely look at the types generated.
444	}
445	if ( ! ResolvExpr::typesCompatibleIgnoreQualifiers( destType->stripReferences(), srcType->stripReferences(), SymTab::Indexer() ) ) {
446	// must keep cast if types are different
447	castExpr->arg = ret;
448	return castExpr;
449	}
450	ret->env = castExpr->env;
451	delete ret->result;
452	ret->result = castExpr->result;
453	assert( ret->get_lvalue() ); // ensure result is lvalue
454	castExpr->env = nullptr;
455	castExpr->arg = nullptr;
456	castExpr->result = nullptr;
457	delete castExpr;
458	return ret;
459	} else {
460	assert( diff == 0 );
461	// conversion between references of the same depth
462	if ( ResolvExpr::typesCompatible( castExpr->result, castExpr->arg->result, SymTab::Indexer() ) && castExpr->isGenerated ) {
463	// Remove useless generated casts
464	PRINT(
465	std::cerr << "types are compatible, removing cast: " << castExpr << std::endl;
466	std::cerr << "-- " << castExpr->result << std::endl;
467	std::cerr << "-- " << castExpr->arg->result << std::endl;
468	)
469	Expression * ret = castExpr->arg;
470	castExpr->arg = nullptr;
471	std::swap( castExpr->env, ret->env );
472	delete castExpr;
473	return ret;
474	}
475	return castExpr;
476	}
477	}
478
479	Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
480	Type * base = refType->base;
481	Type::Qualifiers qualifiers = refType->get_qualifiers();
482	refType->base = nullptr;
483	delete refType;
484	return new PointerType( qualifiers, base );
485	}
486
487	template<typename Func>
488	Expression * GeneralizedLvalue::applyTransformation( Expression * expr, Expression * arg, Func mkExpr ) {
489	if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( arg ) ) {
490	Expression * arg1 = commaExpr->arg1->clone();
491	Expression * arg2 = commaExpr->arg2->clone();
492	Expression * ret = new CommaExpr( arg1, mkExpr( arg2 )->acceptMutator( *visitor ) );
493	ret->env = expr->env;
494	expr->env = nullptr;
495	delete expr;
496	return ret;
497	} else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( arg ) ) {
498	Expression * arg1 = condExpr->arg1->clone();
499	Expression * arg2 = condExpr->arg2->clone();
500	Expression * arg3 = condExpr->arg3->clone();
501	ConditionalExpr * ret = new ConditionalExpr( arg1, mkExpr( arg2 )->acceptMutator( visitor ), mkExpr( arg3 )->acceptMutator( visitor ) );
502	ret->env = expr->env;
503	expr->env = nullptr;
504	delete expr;
505
506	// conditional expr type may not be either of the argument types, need to unify
507	using namespace ResolvExpr;
508	Type* commonType = nullptr;
509	TypeEnvironment newEnv;
510	AssertionSet needAssertions, haveAssertions;
511	OpenVarSet openVars;
512	unify( ret->arg2->result, ret->arg3->result, newEnv, needAssertions, haveAssertions, openVars, SymTab::Indexer(), commonType );
513	ret->result = commonType ? commonType : ret->arg2->result->clone();
514	return ret;
515	}
516	return expr;
517	}
518
519	Expression * GeneralizedLvalue::postmutate( MemberExpr * memExpr ) {
520	return applyTransformation( memExpr, memExpr->aggregate, [=]( Expression * aggr ) { return new MemberExpr( memExpr->member, aggr ); } );
521	}
522
523	Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
524	return applyTransformation( addrExpr, addrExpr->arg, []( Expression * arg ) { return new AddressExpr( arg ); } );
525	}
526
527	Expression * CollapseAddrDeref::postmutate( AddressExpr * addrExpr ) {
528	Expression * arg = addrExpr->arg;
529	if ( isIntrinsicReference( arg ) ) {
530	std::string fname = InitTweak::getFunctionName( arg );
531	if ( fname == "*?" ) {
532	Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
533	Expression * ret = arg0;
534	ret->set_env( addrExpr->env );
535	arg0 = nullptr;
536	addrExpr->env = nullptr;
537	delete addrExpr;
538	return ret;
539	}
540	} else if ( CastExpr * castExpr = dynamic_cast< CastExpr * > ( arg ) ) {
541	// need to move cast to pointer type out a level since address of pointer
542	// is not valid C code (can be introduced in prior passes, e.g., InstantiateGeneric)
543	if ( InitTweak::getPointerBase( castExpr->result ) ) {
544	addrExpr->arg = castExpr->arg;
545	castExpr->arg = addrExpr;
546	castExpr->result = new PointerType( Type::Qualifiers(), castExpr->result );
547	return castExpr;
548	}
549	}
550	return addrExpr;
551	}
552
553	Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
554	if ( isIntrinsicReference( appExpr ) ) {
555	std::string fname = InitTweak::getFunctionName( appExpr );
556	if ( fname == "*?" ) {
557	Expression * arg = InitTweak::getCallArg( appExpr, 0 );
558	// xxx - this isn't right, because it can remove casts that should be there...
559	// while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
560	// arg = castExpr->get_arg();
561	// }
562	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
563	Expression * ret = addrExpr->arg;
564	ret->env = appExpr->env;
565	addrExpr->arg = nullptr;
566	appExpr->env = nullptr;
567	delete appExpr;
568	return ret;
569	}
570	}
571	}
572	return appExpr;
573	}
574	} // namespace
575	} // namespace GenPoly
576
577	// Local Variables: //
578	// tab-width: 4 //
579	// mode: c++ //
580	// compile-command: "make install" //
581	// End: //

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