source: src/ResolvExpr/ConversionCost.cc@ 520145b

ADT aaron-thesis arm-eh ast-experimental cleanup-dtors deferred_resn demangler enum forall-pointer-decay jacob/cs343-translation jenkins-sandbox new-ast new-ast-unique-expr new-env no_list persistent-indexer pthread-emulation qualifiedEnum resolv-new with_gc
Last change on this file since 520145b was eddb399, checked in by Rob Schluntz <rschlunt@…>, 8 years ago

Add debug print to convertToReferenceCost
  • Property mode set to 100644
File size: 18.2 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 : Mon Sep 25 15:43:34 2017
13// Update Count : 10
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->name; )
47 if ( env.lookup( destAsTypeInst->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->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->base ) {
59 return conversionCost( src, type->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 SymTab::Indexer &, const TypeEnvironment & env ){
80 return ptrsAssignable( t1, t2, env );
81 });
82 } else {
83 PassVisitor<ConversionCost> converter( dest, indexer, env, conversionCost );
84 src->accept( converter );
85 if ( converter.pass.get_cost() == Cost::infinity ) {
86 return Cost::infinity;
87 } else {
88 return converter.pass.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 << " " << src << " / " << dest << std::endl; )
95 if ( diff > 0 ) {
96 // TODO: document this
97 Cost cost = convertToReferenceCost( strict_dynamic_cast< ReferenceType * >( src )->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 )->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 Type::Qualifiers tq1 = srcAsRef->base->get_qualifiers();
111 Type::Qualifiers tq2 = destAsRef->base->get_qualifiers();
112 if ( tq1 <= tq2 && typesCompatibleIgnoreQualifiers( srcAsRef->base, destAsRef->base, indexer, env ) ) {
113 PRINT( std::cerr << " :: compatible and good qualifiers" << std::endl; )
114 if ( tq1 == tq2 ) {
115 // types are the same
116 return Cost::zero;
117 } else {
118 // types are the same, except otherPointer has more qualifiers
119 return Cost::safe;
120 }
121 } else { // xxx - this discards reference qualifiers from consideration -- reducing qualifiers is a safe conversion; is this right?
122 int assignResult = func( srcAsRef->base, destAsRef->base, indexer, env );
123 PRINT( std::cerr << "comparing references: " << assignResult << " " << srcAsRef << " " << destAsRef << std::endl; )
124 if ( assignResult > 0 ) {
125 return Cost::safe;
126 } else if ( assignResult < 0 ) {
127 return Cost::unsafe;
128 } // if
129 } // if
130 } else {
131 PRINT( std::cerr << "reference to rvalue conversion" << std::endl; )
132 PassVisitor<ConversionCost> converter( dest, indexer, env, conversionCost );
133 src->accept( converter );
134 return converter.pass.get_cost();
135 } // if
136 } else {
137 ReferenceType * destAsRef = dynamic_cast< ReferenceType * >( dest );
138 assert( diff == -1 && destAsRef );
139 PRINT( std::cerr << "dest is: " << dest << " / src is: " << src << std::endl; )
140 if ( typesCompatibleIgnoreQualifiers( src, destAsRef->base, indexer, env ) ) {
141 PRINT( std::cerr << "converting compatible base type" << std::endl; )
142 if ( src->get_lvalue() ) {
143 PRINT(
144 std::cerr << "lvalue to reference conversion" << std::endl;
145 std::cerr << src << " => " << destAsRef << std::endl;
146 )
147 // lvalue-to-reference conversion: cv lvalue T => cv T &
148 if ( src->get_qualifiers() == destAsRef->base->get_qualifiers() ) {
149 return Cost::reference; // cost needs to be non-zero to add cast
150 } if ( src->get_qualifiers() < destAsRef->base->get_qualifiers() ) {
151 return Cost::safe; // cost needs to be higher than previous cast to differentiate adding qualifiers vs. keeping same
152 } else {
153 return Cost::unsafe;
154 } // if
155 } else if ( destAsRef->base->get_const() ) {
156 PRINT( std::cerr << "rvalue to const ref conversion" << std::endl; )
157 // rvalue-to-const-reference conversion: T => const T &
158 return Cost::safe;
159 } else {
160 PRINT( std::cerr << "rvalue to non-const reference conversion" << std::endl; )
161 // rvalue-to-reference conversion: T => T &
162 return Cost::unsafe;
163 } // if
164 } // if
165 PRINT( std::cerr << "attempting to convert from incompatible base type -- fail" << std::endl; )
166 }
167 return Cost::infinity;
168 }
169
170 Cost convertToReferenceCost( Type * src, ReferenceType * dest, const SymTab::Indexer & indexer, const TypeEnvironment & env, PtrsFunction func ) {
171 int sdepth = src->referenceDepth(), ddepth = dest->referenceDepth();
172 Cost cost = convertToReferenceCost( src, dest, sdepth-ddepth, indexer, env, func );
173 PRINT( std::cerr << "convertToReferenceCost result: " << cost << std::endl; )
174 return cost;
175 }
176
177 ConversionCost::ConversionCost( Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env, CostFunction costFunc )
178 : dest( dest ), indexer( indexer ), cost( Cost::infinity ), env( env ), costFunc( costFunc ) {
179 }
180
181/*
182 Old
183 ===
184 Double
185 |
186 Float
187 |
188 ULong
189 / \
190 UInt Long
191 \ /
192 Int
193 |
194 Ushort
195 |
196 Short
197 |
198 Uchar
199 / \
200 Schar Char
201
202 New
203 ===
204 +-----LongDoubleComplex--+
205 LongDouble--+ | +-LongDoubleImag
206 | +---DoubleComplex---+ |
207 Double------+ | +----DoubleImag
208 | +-FloatComplex-+ |
209 Float---------+ +-------FloatImag
210 |
211 ULongLong
212 |
213 LongLong
214 |
215 ULong
216 / \
217 UInt Long
218 \ /
219 Int
220 |
221 Ushort
222 |
223 Short
224 |
225 Uchar
226 / \
227 Schar Char
228 \ /
229 Bool
230*/
231
232 static const int costMatrix[ BasicType::NUMBER_OF_BASIC_TYPES ][ BasicType::NUMBER_OF_BASIC_TYPES ] = {
233 /* Src \ Dest: Bool Char SChar UChar Short UShort Int UInt Long ULong LLong ULLong Float Double LDbl FCplex DCplex LDCplex FImag DImag LDImag I128, U128 */
234 /* Bool */ { 0, 1, 1, 2, 3, 4, 5, 6, 6, 7, 8, 9, 12, 13, 14, 12, 13, 14, -1, -1, -1, 10, 11, },
235 /* Char */ { -1, 0, -1, 1, 2, 3, 4, 5, 5, 6, 7, 8, 11, 12, 13, 11, 12, 13, -1, -1, -1, 9, 10, },
236 /* SChar */ { -1, -1, 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 11, 12, 13, 11, 12, 13, -1, -1, -1, 9, 10, },
237 /* UChar */ { -1, -1, -1, 0, 1, 2, 3, 4, 4, 5, 6, 7, 10, 11, 12, 10, 11, 12, -1, -1, -1, 8, 9, },
238 /* Short */ { -1, -1, -1, -1, 0, 1, 2, 3, 3, 4, 5, 6, 9, 10, 11, 9, 10, 11, -1, -1, -1, 7, 8, },
239 /* UShort */{ -1, -1, -1, -1, -1, 0, 1, 2, 2, 3, 4, 5, 8, 9, 10, 8, 9, 10, -1, -1, -1, 6, 7, },
240 /* Int */ { -1, -1, -1, -1, -1, -1, 0, 1, 1, 2, 3, 4, 7, 8, 9, 7, 8, 9, -1, -1, -1, 5, 6, },
241 /* UInt */ { -1, -1, -1, -1, -1, -1, -1, 0, -1, 1, 2, 3, 6, 7, 8, 6, 7, 8, -1, -1, -1, 4, 5, },
242 /* Long */ { -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 6, 7, 8, 6, 7, 8, -1, -1, -1, 4, 5, },
243 /* ULong */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 5, 6, 7, 5, 6, 7, -1, -1, -1, 3, 4, },
244 /* LLong */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 4, 5, 6, 4, 5, 6, -1, -1, -1, 2, 3, },
245 /* ULLong */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 3, 4, 5, 3, 4, 5, -1, -1, -1, 1, 2, },
246
247 /* Float */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 1, 2, 3, -1, -1, -1, -1, -1, },
248 /* Double */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, -1, 1, 2, -1, -1, -1, -1, -1, },
249 /* LDbl */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, -1, -1, 1, -1, -1, -1, -1, -1, },
250 /* FCplex */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, -1, -1, -1, -1, -1, },
251 /* DCplex */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, -1, -1, -1, -1, -1, },
252 /* LDCplex */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, -1, -1, -1, -1, -1, },
253 /* FImag */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, 3, 0, 1, 2, -1, -1, },
254 /* DImag */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, -1, 0, 1, -1, -1, },
255 /* LDImag */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 0, -1, -1, },
256
257 /* I128 */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 2, 3, 4, 3, 4, 5, -1, -1, -1, 0, 1, },
258 /* U128 */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, 3, 2, 3, 4, -1, -1, -1, -1, 0, },
259 };
260
261 void ConversionCost::postvisit( VoidType * ) {
262 cost = Cost::infinity;
263 }
264
265 void ConversionCost::postvisit(BasicType *basicType) {
266 if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
267 int tableResult = costMatrix[ basicType->get_kind() ][ destAsBasic->get_kind() ];
268 if ( tableResult == -1 ) {
269 cost = Cost::unsafe;
270 } else {
271 cost = Cost::zero;
272 cost.incSafe( tableResult );
273 } // if
274 } else if ( dynamic_cast< EnumInstType *>( dest ) ) {
275 // xxx - not positive this is correct, but appears to allow casting int => enum
276 cost = Cost::unsafe;
277 } else if ( dynamic_cast< ZeroType* >( dest ) != nullptr || dynamic_cast< OneType* >( dest ) != nullptr ) {
278 cost = Cost::unsafe;
279 } // if
280 }
281
282 void ConversionCost::postvisit( PointerType * pointerType ) {
283 if ( PointerType *destAsPtr = dynamic_cast< PointerType* >( dest ) ) {
284 PRINT( std::cerr << pointerType << " ===> " << destAsPtr << std::endl; )
285 Type::Qualifiers tq1 = pointerType->base->get_qualifiers();
286 Type::Qualifiers tq2 = destAsPtr->base->get_qualifiers();
287 if ( tq1 <= tq2 && typesCompatibleIgnoreQualifiers( pointerType->base, destAsPtr->base, indexer, env ) ) {
288 PRINT( std::cerr << " :: compatible and good qualifiers" << std::endl; )
289 if ( tq1 == tq2 ) {
290 // types are the same
291 cost = Cost::zero;
292 } else {
293 // types are the same, except otherPointer has more qualifiers
294 cost = Cost::safe;
295 }
296 } else {
297 int assignResult = ptrsAssignable( pointerType->base, destAsPtr->base, env );
298 PRINT( std::cerr << " :: " << assignResult << std::endl; )
299 if ( assignResult > 0 && tq1 <= tq2 ) {
300 // xxx - want the case where qualifiers are added to be more expensive than the case where qualifiers are the same. Is 1 safe vs. 2 safe correct?
301 if ( tq1 == tq2 ) {
302 cost = Cost::safe;
303 } else if ( tq1 < tq2 ) {
304 cost = Cost::safe+Cost::safe;
305 }
306 } else if ( assignResult < 0 ) {
307 cost = Cost::unsafe;
308 } // if
309 // assignResult == 0 means Cost::Infinity
310 } // if
311 } else if ( dynamic_cast< ZeroType * >( dest ) ) {
312 cost = Cost::unsafe;
313 } // if
314 }
315
316 void ConversionCost::postvisit( ArrayType * ) {}
317
318 void ConversionCost::postvisit( ReferenceType * refType ) {
319 // Note: dest can never be a reference, since it would have been caught in an earlier check
320 assert( ! dynamic_cast< ReferenceType * >( dest ) );
321 // convert reference to rvalue: cv T1 & => T2
322 // recursively compute conversion cost from T1 to T2.
323 // cv can be safely dropped because of 'implicit dereference' behavior.
324 cost = costFunc( refType->base, dest, indexer, env );
325 if ( refType->base->get_qualifiers() == dest->get_qualifiers() ) {
326 cost.incReference(); // prefer exact qualifiers
327 } else if ( refType->base->get_qualifiers() < dest->get_qualifiers() ) {
328 cost.incSafe(); // then gaining qualifiers
329 } else {
330 cost.incUnsafe(); // lose qualifiers as last resort
331 }
332 PRINT( std::cerr << refType << " ==> " << dest << " " << cost << std::endl; )
333 }
334
335 void ConversionCost::postvisit( FunctionType * ) {}
336
337 void ConversionCost::postvisit( StructInstType * inst ) {
338 if ( StructInstType *destAsInst = dynamic_cast< StructInstType* >( dest ) ) {
339 if ( inst->name == destAsInst->name ) {
340 cost = Cost::zero;
341 } // if
342 } // if
343 }
344
345 void ConversionCost::postvisit( UnionInstType * inst ) {
346 if ( UnionInstType *destAsInst = dynamic_cast< UnionInstType* >( dest ) ) {
347 if ( inst->name == destAsInst->name ) {
348 cost = Cost::zero;
349 } // if
350 } // if
351 }
352
353 void ConversionCost::postvisit( EnumInstType * ) {
354 static Type::Qualifiers q;
355 static BasicType integer( q, BasicType::SignedInt );
356 cost = costFunc( &integer, dest, indexer, env ); // safe if dest >= int
357 if ( cost < Cost::unsafe ) {
358 cost.incSafe();
359 } // if
360 }
361
362 void ConversionCost::postvisit( TraitInstType * ) {}
363
364 void ConversionCost::postvisit( TypeInstType *inst ) {
365 EqvClass eqvClass;
366 NamedTypeDecl *namedType;
367 if ( env.lookup( inst->name, eqvClass ) ) {
368 cost = costFunc( eqvClass.type, dest, indexer, env );
369 } else if ( TypeInstType *destAsInst = dynamic_cast< TypeInstType* >( dest ) ) {
370 if ( inst->name == destAsInst->name ) {
371 cost = Cost::zero;
372 }
373 } else if ( ( namedType = indexer.lookupType( inst->name ) ) ) {
374 TypeDecl *type = dynamic_cast< TypeDecl* >( namedType );
375 // all typedefs should be gone by this point
376 assert( type );
377 if ( type->base ) {
378 cost = costFunc( type->base, dest, indexer, env ) + Cost::safe;
379 } // if
380 } // if
381 }
382
383 void ConversionCost::postvisit( TupleType * tupleType ) {
384 Cost c = Cost::zero;
385 if ( TupleType * destAsTuple = dynamic_cast< TupleType * >( dest ) ) {
386 std::list< Type * >::const_iterator srcIt = tupleType->types.begin();
387 std::list< Type * >::const_iterator destIt = destAsTuple->types.begin();
388 while ( srcIt != tupleType->types.end() && destIt != destAsTuple->types.end() ) {
389 Cost newCost = costFunc( *srcIt++, *destIt++, indexer, env );
390 if ( newCost == Cost::infinity ) {
391 return;
392 } // if
393 c += newCost;
394 } // while
395 if ( destIt != destAsTuple->types.end() ) {
396 cost = Cost::infinity;
397 } else {
398 cost = c;
399 } // if
400 } // if
401 }
402
403 void ConversionCost::postvisit( VarArgsType * ) {
404 if ( dynamic_cast< VarArgsType* >( dest ) ) {
405 cost = Cost::zero;
406 }
407 }
408
409 void ConversionCost::postvisit( ZeroType * ) {
410 if ( dynamic_cast< ZeroType * >( dest ) ) {
411 cost = Cost::zero;
412 } else if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
413 // copied from visit(BasicType*) for signed int, but +1 for safe conversions
414 int tableResult = costMatrix[ BasicType::SignedInt ][ destAsBasic->get_kind() ];
415 if ( tableResult == -1 ) {
416 cost = Cost::unsafe;
417 } else {
418 cost = Cost::zero;
419 cost.incSafe( tableResult + 1 );
420 }
421 } else if ( dynamic_cast< PointerType* >( dest ) ) {
422 cost = Cost::safe;
423 }
424 }
425
426 void ConversionCost::postvisit( OneType * ) {
427 if ( dynamic_cast< OneType * >( dest ) ) {
428 cost = Cost::zero;
429 } else if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
430 // copied from visit(BasicType*) for signed int, but +1 for safe conversions
431 int tableResult = costMatrix[ BasicType::SignedInt ][ destAsBasic->get_kind() ];
432 if ( tableResult == -1 ) {
433 cost = Cost::unsafe;
434 } else {
435 cost = Cost::zero;
436 cost.incSafe( tableResult + 1 );
437 }
438 }
439 }
440} // namespace ResolvExpr
441
442// Local Variables: //
443// tab-width: 4 //
444// mode: c++ //
445// compile-command: "make install" //
446// End: //
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