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source: src/GenPoly/Lvalue.cc @ d335627

ADTaaron-thesisarm-ehast-experimentalcleanup-dtorsdeferred_resndemanglerenumforall-pointer-decayjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-exprnew-envno_listpersistent-indexerpthread-emulationqualifiedEnumresolv-newwith_gc

Last change on this file since d335627 was d335627, checked in by Rob Schluntz <rschlunt@…>, 7 years ago
Add address-of to intrinsic reference-returning functions that are arguments to non-intrinsic functions
Property mode set to `100644`
File size: 12.9 KB

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1	//
2	// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3	//
4	// The contents of this file are covered under the licence agreement in the
5	// file "LICENCE" distributed with Cforall.
6	//
7	// Lvalue.cc --
8	//
9	// Author : Richard C. Bilson
10	// Created On : Mon May 18 07:44:20 2015
11	// Last Modified By : Peter A. Buhr
12	// Last Modified On : Fri Mar 17 09:11:18 2017
13	// Update Count : 5
14	//
15
16	#include <cassert>
17
18	#include "Lvalue.h"
19
20	#include "GenPoly.h"
21
22	#include "SynTree/Declaration.h"
23	#include "SynTree/Type.h"
24	#include "SynTree/Expression.h"
25	#include "SynTree/Statement.h"
26	#include "SynTree/Visitor.h"
27	#include "SynTree/Mutator.h"
28	#include "SymTab/Indexer.h"
29	#include "SymTab/Autogen.h"
30	#include "ResolvExpr/Resolver.h"
31	#include "ResolvExpr/typeops.h"
32
33	#include "Common/UniqueName.h"
34	#include "Common/utility.h"
35	#include "InitTweak/InitTweak.h"
36
37	#include "Common/PassVisitor.h"
38
39	// need to be careful about polymorphic references... e.g. in *? (___operator_deref__A0_1_0_0__Fd0_Pd0_intrinsic___1)
40	// the variable is automatically dereferenced and this causes errors dereferencing void*.
41
42	#if 0
43	#define PRINT(x) x
44	#else
45	#define PRINT(x)
46	#endif
47
48	namespace GenPoly {
49	namespace {
50	// TODO: fold this into the general createDeref function??
51	Expression * mkDeref( Expression * arg ) {
52	if ( SymTab::dereferenceOperator ) {
53	VariableExpr * deref = new VariableExpr( SymTab::dereferenceOperator );
54	deref->set_result( new PointerType( Type::Qualifiers(), deref->get_result() ) );
55	Type * base = InitTweak::getPointerBase( arg->get_result() );
56	assertf( base, "expected pointer type in dereference (type was %s)", toString( arg->get_result() ).c_str() );
57	ApplicationExpr * ret = new ApplicationExpr( deref, { arg } );
58	delete ret->get_result();
59	ret->set_result( new ReferenceType( Type::Qualifiers(), base->clone() ) );
60	return ret;
61	} else {
62	return UntypedExpr::createDeref( arg );
63	}
64	}
65
66	struct ReferenceConversions final {
67	Expression * postmutate( CastExpr * castExpr );
68	};
69
70	/// Intrinsic functions that take reference parameters don't REALLY take reference parameters -- their reference arguments must always be implicitly dereferenced.
71	struct FixIntrinsicArgs final {
72	Expression * postmutate( ApplicationExpr *appExpr );
73	};
74
75
76	/// Replace reference types with pointer types
77	struct ReferenceTypeElimination final {
78	Type * postmutate( ReferenceType * refType );
79	};
80
81	/// GCC-like Generalized Lvalues (which have since been removed from GCC)
82	/// https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
83	/// Replaces &(a,b) with (a, &b), &(a ? b : c) with (a ? &b : &c)
84	struct GeneralizedLvalue final : public WithVisitorRef<GeneralizedLvalue> {
85	Expression * postmutate( AddressExpr * addressExpr );
86	};
87
88	/// Removes redundant &/& pattern that this pass can generate
89	struct CollapseAddrDeref final {
90	Expression * postmutate( AddressExpr * addressExpr );
91	Expression * postmutate( ApplicationExpr * appExpr );
92	};
93	} // namespace
94
95	void convertLvalue( std::list< Declaration* >& translationUnit ) {
96	std::cerr << "convertLvalue" << std::endl;
97	PassVisitor<ReferenceConversions> refCvt;
98	PassVisitor<ReferenceTypeElimination> elim;
99	PassVisitor<GeneralizedLvalue> genLval;
100	PassVisitor<FixIntrinsicArgs> fixer;
101	PassVisitor<CollapseAddrDeref> collapser;
102	mutateAll( translationUnit, refCvt );
103	mutateAll( translationUnit, fixer );
104	mutateAll( translationUnit, elim );
105	mutateAll( translationUnit, genLval );
106	mutateAll( translationUnit, collapser );
107	}
108
109	namespace {
110	Type* isLvalueRet( FunctionType *function ) {
111	if ( function->get_returnVals().empty() ) return 0;
112	Type *ty = function->get_returnVals().front()->get_type();
113	return dynamic_cast< ReferenceType * >( ty ) ;
114	}
115
116	bool isIntrinsicApp( ApplicationExpr *appExpr ) {
117	if ( VariableExpr varExpr = dynamic_cast< VariableExpr >( appExpr->get_function() ) ) {
118	return varExpr->get_var()->get_linkage() == LinkageSpec::Intrinsic;
119	} else {
120	return false;
121	} // if
122	}
123
124	bool isDeref( Expression * expr ) {
125	if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
126	return InitTweak::getFunctionName( untyped ) == "*?";
127	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
128	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
129	return func->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getFunctionName( appExpr ) == "*?";
130	}
131	}
132	return false;
133	}
134
135	bool isIntrinsicReference( Expression * expr ) {
136	if ( isDeref( expr ) ) return true;
137	else if ( UntypedExpr * untyped = dynamic_cast< UntypedExpr * >( expr ) ) {
138	return InitTweak::getFunctionName( untyped ) == "?[?]";
139	} else if ( ApplicationExpr * appExpr = dynamic_cast< ApplicationExpr * > ( expr ) ) {
140	if ( DeclarationWithType * func = InitTweak::getFunction( appExpr ) ) {
141	return func->get_linkage() == LinkageSpec::Intrinsic && InitTweak::getFunctionName( appExpr ) == "?[?]";
142	}
143	}
144	return false;
145	}
146
147	// xxx - might need to & every * (or every * that is an arg to non-intrinsic function??)
148	Expression * FixIntrinsicArgs::postmutate( ApplicationExpr * appExpr ) {
149	// intrinsic functions don't really take reference-typed parameters, so they require an implicit dereference on their arguments.
150	if ( DeclarationWithType * function = InitTweak::getFunction( appExpr ) ) {
151	FunctionType * ftype = GenPoly::getFunctionType( function->get_type() );
152	assertf( ftype, "Function declaration does not have function type." );
153	// can be of differing lengths only when function is variadic
154	assertf( ftype->get_parameters().size() == appExpr->get_args().size() \|\| ftype->get_isVarArgs(), "ApplicationExpr args do not match formal parameter type." );
155	unsigned int i = 0;
156	const unsigned int end = ftype->get_parameters().size();
157	for ( auto p : unsafe_group_iterate( appExpr->get_args(), ftype->get_parameters() ) ) {
158	if (i == end) break;
159	Expression *& arg = std::get<0>( p );
160	Type * formal = std::get<1>( p )->get_type();
161	PRINT(
162	std::cerr << "pair<0>: " << arg << std::endl;
163	std::cerr << "pair<1>: " << formal << std::endl;
164	)
165	if ( dynamic_cast<ReferenceType*>( formal ) ) {
166	if ( isIntrinsicReference( arg ) ) {
167	if ( function->get_linkage() != LinkageSpec::Intrinsic ) { // intrinsic functions that turn pointers into references
168	// if argument is dereference or array subscript, the result isn't REALLY a reference, so it's not necessary to fix the argument
169	PRINT( std::cerr << "is intrinsic arg in non-intrinsic call - adding address" << std::endl; )
170	arg = new AddressExpr( arg );
171	}
172	} else if ( function->get_linkage() == LinkageSpec::Intrinsic ) {
173	// if the parameter is a reference, add a dereference to the reference-typed argument.
174	Type * baseType = InitTweak::getPointerBase( arg->get_result() );
175	assertf( baseType, "parameter is reference, arg must be pointer or reference: %s", toString( arg->get_result() ) );
176	PointerType * ptrType = new PointerType( Type::Qualifiers(), baseType->clone() );
177	delete arg->get_result();
178	arg->set_result( ptrType );
179	arg = mkDeref( arg );
180	}
181	}
182	++i;
183	}
184	}
185	return appExpr;
186	}
187
188	Expression * ReferenceConversions::postmutate( CastExpr * castExpr ) {
189	// xxx - is it possible to convert directly between reference types with a different base? E.g.,
190	// int x;
191	// (double&)x;
192	// At the moment, I am working off of the assumption that this is illegal, thus the cast becomes redundant
193	// after this pass, so trash the cast altogether. If that changes, care must be taken to insert the correct
194	// pointer casts in the right places.
195
196	// conversion to reference type
197	if ( ReferenceType * refType = dynamic_cast< ReferenceType * >( castExpr->get_result() ) ) {
198	(void)refType;
199	if ( ReferenceType * otherRef = dynamic_cast< ReferenceType * >( castExpr->get_arg()->get_result() ) ) {
200	// nothing to do if casting from reference to reference.
201	(void)otherRef;
202	PRINT( std::cerr << "convert reference to reference -- nop" << std::endl; )
203	if ( isIntrinsicReference( castExpr->get_arg() ) ) {
204	Expression * callExpr = castExpr->get_arg();
205	PRINT(
206	std::cerr << "but arg is deref -- &" << std::endl;
207	std::cerr << callExpr << std::endl;
208	)
209	// move environment out to new top-level
210	callExpr->set_env( castExpr->get_env() );
211	castExpr->set_arg( nullptr );
212	castExpr->set_env( nullptr );
213	delete castExpr;
214	return callExpr;
215	}
216	assertf( false, "non-intrinsic reference with cast of reference to reference not yet supported: ", toString( castExpr ) );
217	PRINT( std::cerr << castExpr << std::endl; )
218	return castExpr;
219	} else if ( castExpr->get_arg()->get_result()->get_lvalue() ) {
220	// conversion from lvalue to reference
221	// xxx - keep cast, but turn into pointer cast??
222	// xxx - memory
223	PRINT(
224	std::cerr << "convert lvalue to reference -- &" << std::endl;
225	std::cerr << castExpr->get_arg() << std::endl;
226	)
227	AddressExpr * ret = new AddressExpr( castExpr->get_arg() );
228	if ( refType->get_base()->get_qualifiers() != castExpr->get_arg()->get_result()->get_qualifiers() ) {
229	// must keep cast if cast-to type is different from the actual type
230	castExpr->set_arg( ret );
231
232	return castExpr;
233	}
234	ret->set_env( castExpr->get_env() );
235	castExpr->set_env( nullptr );
236	castExpr->set_arg( nullptr );
237	delete castExpr;
238	return ret;
239	} else {
240	// rvalue to reference conversion -- introduce temporary
241	}
242	assertf( false, "Only conversions to reference from lvalue are currently supported: %s", toString( castExpr ).c_str() );
243	} else if ( ReferenceType * refType = dynamic_cast< ReferenceType * >( castExpr->get_arg()->get_result() ) ) {
244	(void)refType;
245	// conversion from reference to rvalue
246	PRINT( std::cerr << "convert reference to rvalue -- *" << std::endl; )
247	PRINT( std::cerr << "was = " << castExpr << std::endl; )
248	Expression * ret = castExpr->get_arg();
249	if ( ! isIntrinsicReference( ret ) ) {
250	// dereference if not already dereferenced
251	ret = mkDeref( ret );
252	}
253	ret->set_env( castExpr->get_env() );
254	castExpr->set_arg( nullptr );
255	castExpr->set_env( nullptr );
256	delete castExpr;
257	PRINT( std::cerr << "now: " << ret << std::endl; )
258	return ret;
259	}
260	return castExpr;
261	}
262
263	Type * ReferenceTypeElimination::postmutate( ReferenceType * refType ) {
264	Type * base = refType->get_base();
265	refType->set_base( nullptr );
266	delete refType;
267	return new PointerType( Type::Qualifiers(), base );
268	}
269
270	Expression * GeneralizedLvalue::postmutate( AddressExpr * addrExpr ) {
271	if ( CommaExpr * commaExpr = dynamic_cast< CommaExpr * >( addrExpr->get_arg() ) ) {
272	Expression * arg1 = commaExpr->get_arg1()->clone();
273	Expression * arg2 = commaExpr->get_arg2()->clone();
274	delete addrExpr;
275	return new CommaExpr( arg1, (new AddressExpr( arg2 ))->acceptMutator( *visitor ) );
276	} else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( addrExpr->get_arg() ) ) {
277	Expression * arg1 = condExpr->get_arg1()->clone();
278	Expression * arg2 = condExpr->get_arg2()->clone();
279	Expression * arg3 = condExpr->get_arg3()->clone();
280	delete addrExpr;
281	return new ConditionalExpr( arg1, (new AddressExpr( arg2 ))->acceptMutator( visitor ), (new AddressExpr( arg3 ))->acceptMutator( visitor ) );
282	}
283	return addrExpr;
284	}
285
286	Expression * CollapseAddrDeref::postmutate( AddressExpr * addressExpr ) {
287	Expression * arg = addressExpr->get_arg();
288	if ( isIntrinsicReference( arg ) ) {
289	std::string fname = InitTweak::getFunctionName( arg );
290	if ( fname == "*?" ) {
291	Expression *& arg0 = InitTweak::getCallArg( arg, 0 );
292	Expression * ret = arg0;
293	ret->set_env( addressExpr->get_env() );
294	arg0 = nullptr;
295	addressExpr->set_env( nullptr );
296	delete addressExpr;
297	return ret;
298	}
299	}
300	return addressExpr;
301	}
302
303	Expression * CollapseAddrDeref::postmutate( ApplicationExpr * appExpr ) {
304	if ( isIntrinsicReference( appExpr ) ) {
305	std::string fname = InitTweak::getFunctionName( appExpr );
306	if ( fname == "*?" ) {
307	Expression * arg = InitTweak::getCallArg( appExpr, 0 );
308	// xxx - this isn't right, because it can remove casts that should be there...
309	// while ( CastExpr * castExpr = dynamic_cast< CastExpr * >( arg ) ) {
310	// arg = castExpr->get_arg();
311	// }
312	if ( AddressExpr * addrExpr = dynamic_cast< AddressExpr * >( arg ) ) {
313	Expression * ret = addrExpr->get_arg();
314	ret->set_env( appExpr->get_env() );
315	addrExpr->set_arg( nullptr );
316	appExpr->set_env( nullptr );
317	delete appExpr;
318	return ret;
319	}
320	}
321	}
322	return appExpr;
323	}
324	} // namespace
325	} // namespace GenPoly
326
327	// Local Variables: //
328	// tab-width: 4 //
329	// mode: c++ //
330	// compile-command: "make install" //
331	// End: //

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