source: src/ResolvExpr/ConversionCost.cc@ 1bc749f

ADT arm-eh ast-experimental cleanup-dtors enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox new-ast new-ast-unique-expr pthread-emulation qualifiedEnum
Last change on this file since 1bc749f was 982832e, checked in by Thierry Delisle <tdelisle@…>, 8 years ago

Merge branch 'master' of plg.uwaterloo.ca:software/cfa/cfa-cc
  • Property mode set to 100644
File size: 17.5 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// ConversionCost.cc --
8//
9// Author : Richard C. Bilson
10// Created On : Sun May 17 07:06:19 2015
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Wed Mar 2 17:35:46 2016
13// Update Count : 6
14//
15
16#include "ConversionCost.h"
17
18#include <cassert> // for assert
19#include <list> // for list, list<>::const_iterator
20#include <string> // for operator==, string
21
22#include "ResolvExpr/Cost.h" // for Cost
23#include "ResolvExpr/TypeEnvironment.h" // for EqvClass, TypeEnvironment
24#include "SymTab/Indexer.h" // for Indexer
25#include "SynTree/Declaration.h" // for TypeDecl, NamedTypeDecl
26#include "SynTree/Type.h" // for Type, BasicType, TypeInstType
27#include "typeops.h" // for typesCompatibleIgnoreQualifiers
28
29namespace ResolvExpr {
30 const Cost Cost::zero = Cost( 0, 0, 0, 0 );
31 const Cost Cost::infinity = Cost( -1, -1, -1, -1 );
32 const Cost Cost::unsafe = Cost( 1, 0, 0, 0 );
33 const Cost Cost::poly = Cost( 0, 1, 0, 0 );
34 const Cost Cost::safe = Cost( 0, 0, 1, 0 );
35 const Cost Cost::reference = Cost( 0, 0, 0, 1 );
36
37#if 0
38#define PRINT(x) x
39#else
40#define PRINT(x)
41#endif
42 Cost conversionCost( Type *src, Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env ) {
43 if ( TypeInstType *destAsTypeInst = dynamic_cast< TypeInstType* >( dest ) ) {
44 EqvClass eqvClass;
45 NamedTypeDecl *namedType;
46 PRINT( std::cerr << "type inst " << destAsTypeInst->get_name(); )
47 if ( env.lookup( destAsTypeInst->get_name(), eqvClass ) ) {
48 if ( eqvClass.type ) {
49 return conversionCost( src, eqvClass.type, indexer, env );
50 } else {
51 return Cost::infinity;
52 }
53 } else if ( ( namedType = indexer.lookupType( destAsTypeInst->get_name() ) ) ) {
54 PRINT( std::cerr << " found" << std::endl; )
55 TypeDecl *type = dynamic_cast< TypeDecl* >( namedType );
56 // all typedefs should be gone by this point
57 assert( type );
58 if ( type->get_base() ) {
59 return conversionCost( src, type->get_base(), indexer, env ) + Cost::safe;
60 } // if
61 } // if
62 PRINT( std::cerr << " not found" << std::endl; )
63 } // if
64 PRINT(
65 std::cerr << "src is ";
66 src->print( std::cerr );
67 std::cerr << std::endl << "dest is ";
68 dest->print( std::cerr );
69 std::cerr << std::endl << "env is" << std::endl;
70 env.print( std::cerr, 8 );
71 )
72 if ( typesCompatibleIgnoreQualifiers( src, dest, indexer, env ) ) {
73 PRINT( std::cerr << "compatible!" << std::endl; )
74 return Cost::zero;
75 } else if ( dynamic_cast< VoidType* >( dest ) ) {
76 return Cost::safe;
77 } else if ( ReferenceType * refType = dynamic_cast< ReferenceType * > ( dest ) ) {
78 PRINT( std::cerr << "conversionCost: dest is reference" << std::endl; )
79 return convertToReferenceCost( src, refType, indexer, env, [](Type * t1, Type * t2, const TypeEnvironment & env, const SymTab::Indexer &){
80 return ptrsAssignable( t1, t2, env );
81 });
82 } else {
83 ConversionCost converter( dest, indexer, env );
84 src->accept( converter );
85 if ( converter.get_cost() == Cost::infinity ) {
86 return Cost::infinity;
87 } else {
88 return converter.get_cost() + Cost::zero;
89 } // if
90 } // if
91 }
92
93 Cost convertToReferenceCost( Type * src, Type * dest, int diff, const SymTab::Indexer & indexer, const TypeEnvironment & env, PtrsFunction func ) {
94 PRINT( std::cerr << "convert to reference cost... diff " << diff << std::endl; )
95 if ( diff > 0 ) {
96 // TODO: document this
97 Cost cost = convertToReferenceCost( strict_dynamic_cast< ReferenceType * >( src )->get_base(), dest, diff-1, indexer, env, func );
98 cost.incReference();
99 return cost;
100 } else if ( diff < -1 ) {
101 // TODO: document this
102 Cost cost = convertToReferenceCost( src, strict_dynamic_cast< ReferenceType * >( dest )->get_base(), diff+1, indexer, env, func );
103 cost.incReference();
104 return cost;
105 } else if ( diff == 0 ) {
106 ReferenceType * srcAsRef = dynamic_cast< ReferenceType * >( src );
107 ReferenceType * destAsRef = dynamic_cast< ReferenceType * >( dest );
108 if ( srcAsRef && destAsRef ) { // pointer-like conversions between references
109 PRINT( std::cerr << "converting between references" << std::endl; )
110 if ( srcAsRef->get_base()->get_qualifiers() <= destAsRef->get_base()->get_qualifiers() && typesCompatibleIgnoreQualifiers( srcAsRef->get_base(), destAsRef->get_base(), indexer, env ) ) {
111 return Cost::safe;
112 } else { // xxx - this discards reference qualifiers from consideration -- reducing qualifiers is a safe conversion; is this right?
113 int assignResult = func( srcAsRef->get_base(), destAsRef->get_base(), env, indexer );
114 PRINT( std::cerr << "comparing references: " << assignResult << " " << srcAsRef << " " << destAsRef << std::endl; )
115 if ( assignResult < 0 ) {
116 return Cost::safe;
117 } else if ( assignResult > 0 ) {
118 return Cost::unsafe;
119 } // if
120 } // if
121 } else {
122 PRINT( std::cerr << "reference to rvalue conversion" << std::endl; )
123 ConversionCost converter( dest, indexer, env );
124 src->accept( converter );
125 return converter.get_cost();
126 } // if
127 } else {
128 ReferenceType * destAsRef = dynamic_cast< ReferenceType * >( dest );
129 assert( diff == -1 && destAsRef );
130 PRINT( std::cerr << "dest is: " << dest << " / src is: " << src << std::endl; )
131 if ( typesCompatibleIgnoreQualifiers( src, destAsRef->get_base(), indexer, env ) ) {
132 PRINT( std::cerr << "converting compatible base type" << std::endl; )
133 if ( src->get_lvalue() ) {
134 PRINT(
135 std::cerr << "lvalue to reference conversion" << std::endl;
136 std::cerr << src << " => " << destAsRef << std::endl;
137 )
138 // lvalue-to-reference conversion: cv lvalue T => cv T &
139 if ( src->get_qualifiers() == destAsRef->get_base()->get_qualifiers() ) {
140 return Cost::reference; // cost needs to be non-zero to add cast
141 } if ( src->get_qualifiers() < destAsRef->get_base()->get_qualifiers() ) {
142 return Cost::safe; // cost needs to be higher than previous cast to differentiate adding qualifiers vs. keeping same
143 } else {
144 return Cost::unsafe;
145 } // if
146 } else if ( destAsRef->get_base()->get_const() ) {
147 PRINT( std::cerr << "rvalue to const ref conversion" << std::endl; )
148 // rvalue-to-const-reference conversion: T => const T &
149 return Cost::safe;
150 } else {
151 PRINT( std::cerr << "rvalue to non-const reference conversion" << std::endl; )
152 // rvalue-to-reference conversion: T => T &
153 return Cost::unsafe;
154 } // if
155 } // if
156 PRINT( std::cerr << "attempting to convert from incompatible base type -- fail" << std::endl; )
157 }
158 return Cost::infinity;
159 }
160
161 Cost convertToReferenceCost( Type * src, ReferenceType * dest, const SymTab::Indexer & indexer, const TypeEnvironment & env, PtrsFunction func ) {
162 int sdepth = src->referenceDepth(), ddepth = dest->referenceDepth();
163 return convertToReferenceCost( src, dest, sdepth-ddepth, indexer, env, func );
164 }
165
166 ConversionCost::ConversionCost( Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env )
167 : dest( dest ), indexer( indexer ), cost( Cost::infinity ), env( env ) {
168 }
169
170/*
171 Old
172 ===
173 Double
174 |
175 Float
176 |
177 ULong
178 / \
179 UInt Long
180 \ /
181 Int
182 |
183 Ushort
184 |
185 Short
186 |
187 Uchar
188 / \
189 Schar Char
190
191 New
192 ===
193 +-----LongDoubleComplex--+
194 LongDouble--+ | +-LongDoubleImag
195 | +---DoubleComplex---+ |
196 Double------+ | +----DoubleImag
197 | +-FloatComplex-+ |
198 Float---------+ +-------FloatImag
199 |
200 ULongLong
201 |
202 LongLong
203 |
204 ULong
205 / \
206 UInt Long
207 \ /
208 Int
209 |
210 Ushort
211 |
212 Short
213 |
214 Uchar
215 / \
216 Schar Char
217 \ /
218 Bool
219*/
220
221 static const int costMatrix[ BasicType::NUMBER_OF_BASIC_TYPES ][ BasicType::NUMBER_OF_BASIC_TYPES ] =
222 {
223 /* Src \ Dest: Bool Char SChar UChar Short UShort Int UInt Long ULong LLong ULLong Float Double LDbl FCplex DCplex LDCplex FImag DImag LDImag */
224 /* Bool */ { 0, 1, 1, 2, 3, 4, 5, 6, 6, 7, 8, 9, 10, 11, 12, 11, 12, 13, -1, -1, -1 },
225 /* Char */ { -1, 0, -1, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 10, 11, 10, 11, 12, -1, -1, -1 },
226 /* SChar */ { -1, -1, 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 10, 11, 10, 11, 12, -1, -1, -1 },
227 /* UChar */ { -1, -1, -1, 0, 1, 2, 3, 4, 4, 5, 6, 7, 8, 9, 10, 9, 10, 11, -1, -1, -1 },
228 /* Short */ { -1, -1, -1, -1, 0, 1, 2, 3, 3, 4, 5, 6, 7, 8, 9, 8, 9, 10, -1, -1, -1 },
229 /* UShort */{ -1, -1, -1, -1, -1, 0, 1, 2, 2, 3, 4, 5, 6, 7, 8, 7, 8, 9, -1, -1, -1 },
230 /* Int */ { -1, -1, -1, -1, -1, -1, 0, 1, 1, 2, 3, 4, 5, 6, 7, 6, 7, 8, -1, -1, -1 },
231 /* UInt */ { -1, -1, -1, -1, -1, -1, -1, 0, -1, 1, 2, 3, 4, 5, 6, 5, 6, 7, -1, -1, -1 },
232 /* Long */ { -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 5, 6, 7, -1, -1, -1 },
233 /* ULong */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 4, 5, 6, -1, -1, -1 },
234 /* LLong */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 3, 4, 5, -1, -1, -1 },
235 /* ULLong */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 2, 3, 4, -1, -1, -1 },
236 /* Float */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 1, 2, 3, -1, -1, -1 },
237 /* Double */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, -1, 1, 2, -1, -1, -1 },
238 /* LDbl */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, -1, -1, 1, -1, -1, -1 },
239 /* FCplex */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, -1, -1, -1 },
240 /* DCplex */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, -1, -1, -1 },
241 /* LDCplex */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, -1, -1, -1 },
242 /* FImag */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, 3, 0, 1, 2 },
243 /* DImag */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, -1, 0, 1 },
244 /* LDImag */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 0 }
245 };
246
247 void ConversionCost::visit( __attribute((unused)) VoidType *voidType ) {
248 cost = Cost::infinity;
249 }
250
251 void ConversionCost::visit(BasicType *basicType) {
252 if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
253 int tableResult = costMatrix[ basicType->get_kind() ][ destAsBasic->get_kind() ];
254 if ( tableResult == -1 ) {
255 cost = Cost::unsafe;
256 } else {
257 cost = Cost::zero;
258 cost.incSafe( tableResult );
259 } // if
260 } else if ( dynamic_cast< EnumInstType *>( dest ) ) {
261 // xxx - not positive this is correct, but appears to allow casting int => enum
262 cost = Cost::unsafe;
263 } else if ( dynamic_cast< ZeroType* >( dest ) != nullptr || dynamic_cast< OneType* >( dest ) != nullptr ) {
264 cost = Cost::unsafe;
265 } // if
266 }
267
268 void ConversionCost::visit(PointerType *pointerType) {
269 if ( PointerType *destAsPtr = dynamic_cast< PointerType* >( dest ) ) {
270 PRINT( std::cerr << pointerType << " ===> " << destAsPtr; )
271 Type::Qualifiers tq1 = pointerType->get_base()->get_qualifiers();
272 Type::Qualifiers tq2 = destAsPtr->get_base()->get_qualifiers();
273 if ( tq1 <= tq2 && typesCompatibleIgnoreQualifiers( pointerType->get_base(), destAsPtr->get_base(), indexer, env ) ) {
274 if ( tq1 == tq2 ) {
275 // types are the same
276 cost = Cost::zero;
277 } else {
278 // types are the same, except otherPointer has more qualifiers
279 PRINT( std::cerr << " :: compatible and good qualifiers" << std::endl; )
280 cost = Cost::safe;
281 }
282 } else { // xxx - this discards qualifiers from consideration -- reducing qualifiers is a safe conversion; is this right?
283 int assignResult = ptrsAssignable( pointerType->get_base(), destAsPtr->get_base(), env );
284 PRINT( std::cerr << " :: " << assignResult << std::endl; )
285 if ( assignResult < 0 && pointerType->get_base()->get_qualifiers() <= destAsPtr->get_qualifiers() ) {
286 cost = Cost::safe;
287 } else if ( assignResult > 0 ) {
288 cost = Cost::unsafe;
289 } // if
290 // assignResult == 0 means Cost::Infinity
291 } // if
292 } else if ( dynamic_cast< ZeroType* >( dest ) != nullptr || dynamic_cast< OneType* >( dest ) != nullptr ) {
293 cost = Cost::unsafe;
294 } // if
295 }
296
297 void ConversionCost::visit(__attribute((unused)) ArrayType *arrayType) {}
298
299 void ConversionCost::visit(ReferenceType *refType) {
300 // Note: dest can never be a reference, since it would have been caught in an earlier check
301 assert( ! dynamic_cast< ReferenceType * >( dest ) );
302 // convert reference to rvalue: cv T1 & => T2
303 // recursively compute conversion cost from T1 to T2.
304 // cv can be safely dropped because of 'implicit dereference' behavior.
305 refType->get_base()->accept( *this );
306 if ( refType->get_base()->get_qualifiers() == dest->get_qualifiers() ) {
307 cost.incReference(); // prefer exact qualifiers
308 } else if ( refType->get_base()->get_qualifiers() < dest->get_qualifiers() ) {
309 cost.incSafe(); // then gaining qualifiers
310 } else {
311 cost.incUnsafe(); // lose qualifiers as last resort
312 }
313 PRINT( std::cerr << refType << " ==> " << dest << " " << cost << std::endl; )
314 }
315
316 void ConversionCost::visit(__attribute((unused)) FunctionType *functionType) {}
317
318 void ConversionCost::visit(StructInstType *inst) {
319 if ( StructInstType *destAsInst = dynamic_cast< StructInstType* >( dest ) ) {
320 if ( inst->get_name() == destAsInst->get_name() ) {
321 cost = Cost::zero;
322 } // if
323 } // if
324 }
325
326 void ConversionCost::visit(UnionInstType *inst) {
327 if ( StructInstType *destAsInst = dynamic_cast< StructInstType* >( dest ) ) {
328 if ( inst->get_name() == destAsInst->get_name() ) {
329 cost = Cost::zero;
330 } // if
331 } // if
332 }
333
334 void ConversionCost::visit( __attribute((unused)) EnumInstType *inst ) {
335 static Type::Qualifiers q;
336 static BasicType integer( q, BasicType::SignedInt );
337 integer.accept( *this ); // safe if dest >= int
338 if ( cost < Cost::unsafe ) {
339 cost.incSafe();
340 } // if
341 }
342
343 void ConversionCost::visit( __attribute((unused)) TraitInstType *inst) {
344 }
345
346 void ConversionCost::visit(TypeInstType *inst) {
347 EqvClass eqvClass;
348 NamedTypeDecl *namedType;
349 if ( env.lookup( inst->get_name(), eqvClass ) ) {
350 cost = conversionCost( eqvClass.type, dest, indexer, env );
351 } else if ( TypeInstType *destAsInst = dynamic_cast< TypeInstType* >( dest ) ) {
352 if ( inst->get_name() == destAsInst->get_name() ) {
353 cost = Cost::zero;
354 }
355 } else if ( ( namedType = indexer.lookupType( inst->get_name() ) ) ) {
356 TypeDecl *type = dynamic_cast< TypeDecl* >( namedType );
357 // all typedefs should be gone by this point
358 assert( type );
359 if ( type->get_base() ) {
360 cost = conversionCost( type->get_base(), dest, indexer, env ) + Cost::safe;
361 } // if
362 } // if
363 }
364
365 void ConversionCost::visit( __attribute((unused)) TupleType *tupleType) {
366 Cost c = Cost::zero;
367 if ( TupleType *destAsTuple = dynamic_cast< TupleType* >( dest ) ) {
368 std::list< Type* >::const_iterator srcIt = tupleType->get_types().begin();
369 std::list< Type* >::const_iterator destIt = destAsTuple->get_types().begin();
370 while ( srcIt != tupleType->get_types().end() && destIt != destAsTuple->get_types().end() ) {
371 Cost newCost = conversionCost( *srcIt++, *destIt++, indexer, env );
372 if ( newCost == Cost::infinity ) {
373 return;
374 } // if
375 c += newCost;
376 } // while
377 if ( destIt != destAsTuple->get_types().end() ) {
378 cost = Cost::infinity;
379 } else {
380 cost = c;
381 } // if
382 } // if
383 }
384
385 void ConversionCost::visit( __attribute((unused)) VarArgsType *varArgsType) {
386 if ( dynamic_cast< VarArgsType* >( dest ) ) {
387 cost = Cost::zero;
388 }
389 }
390
391 void ConversionCost::visit( __attribute((unused)) ZeroType *zeroType) {
392 if ( dynamic_cast< ZeroType* >( dest ) ) {
393 cost = Cost::zero;
394 } else if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
395 // copied from visit(BasicType*) for signed int, but +1 for safe conversions
396 int tableResult = costMatrix[ BasicType::SignedInt ][ destAsBasic->get_kind() ];
397 if ( tableResult == -1 ) {
398 cost = Cost::unsafe;
399 } else {
400 cost = Cost::zero;
401 cost.incSafe( tableResult + 1 );
402 }
403 } else if ( dynamic_cast< PointerType* >( dest ) ) {
404 cost = Cost::safe;
405 }
406 }
407
408 void ConversionCost::visit( __attribute((unused)) OneType *oneType) {
409 if ( dynamic_cast< OneType* >( dest ) ) {
410 cost = Cost::zero;
411 } else if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
412 // copied from visit(BasicType*) for signed int, but +1 for safe conversions
413 int tableResult = costMatrix[ BasicType::SignedInt ][ destAsBasic->get_kind() ];
414 if ( tableResult == -1 ) {
415 cost = Cost::unsafe;
416 } else {
417 cost = Cost::zero;
418 cost.incSafe( tableResult + 1 );
419 }
420 }
421 }
422} // namespace ResolvExpr
423
424// Local Variables: //
425// tab-width: 4 //
426// mode: c++ //
427// compile-command: "make install" //
428// End: //
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