source: src/ResolvExpr/ConversionCost.cc@ 2a6c115

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 with_gc
Last change on this file since 2a6c115 was 00ac42e, checked in by Aaron Moss <a3moss@…>, 7 years ago

stop eagerly copying EqvClass on lookup
  • Property mode set to 100644
File size: 18.8 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 PRINT( std::cerr << "type inst " << destAsTypeInst->name; )
45 if ( const EqvClass* eqvClass = env.lookup( destAsTypeInst->name ) ) {
46 if ( eqvClass->type ) {
47 return conversionCost( src, eqvClass->type, indexer, env );
48 } else {
49 return Cost::infinity;
50 }
51 } else if ( NamedTypeDecl *namedType = indexer.lookupType( destAsTypeInst->name ) ) {
52 PRINT( std::cerr << " found" << std::endl; )
53 TypeDecl *type = dynamic_cast< TypeDecl* >( namedType );
54 // all typedefs should be gone by this point
55 assert( type );
56 if ( type->base ) {
57 return conversionCost( src, type->base, indexer, env ) + Cost::safe;
58 } // if
59 } // if
60 PRINT( std::cerr << " not found" << std::endl; )
61 } // if
62 PRINT(
63 std::cerr << "src is ";
64 src->print( std::cerr );
65 std::cerr << std::endl << "dest is ";
66 dest->print( std::cerr );
67 std::cerr << std::endl << "env is" << std::endl;
68 env.print( std::cerr, 8 );
69 )
70 if ( typesCompatibleIgnoreQualifiers( src, dest, indexer, env ) ) {
71 PRINT( std::cerr << "compatible!" << std::endl; )
72 return Cost::zero;
73 } else if ( dynamic_cast< VoidType* >( dest ) ) {
74 return Cost::safe;
75 } else if ( ReferenceType * refType = dynamic_cast< ReferenceType * > ( dest ) ) {
76 PRINT( std::cerr << "conversionCost: dest is reference" << std::endl; )
77 return convertToReferenceCost( src, refType, indexer, env, [](Type * t1, Type * t2, const SymTab::Indexer &, const TypeEnvironment & env ){
78 return ptrsAssignable( t1, t2, env );
79 });
80 } else {
81 PassVisitor<ConversionCost> converter( dest, indexer, env, conversionCost );
82 src->accept( converter );
83 if ( converter.pass.get_cost() == Cost::infinity ) {
84 return Cost::infinity;
85 } else {
86 return converter.pass.get_cost() + Cost::zero;
87 } // if
88 } // if
89 }
90
91 Cost convertToReferenceCost( Type * src, Type * dest, int diff, const SymTab::Indexer & indexer, const TypeEnvironment & env, PtrsFunction func ) {
92 PRINT( std::cerr << "convert to reference cost... diff " << diff << " " << src << " / " << dest << std::endl; )
93 if ( diff > 0 ) {
94 // TODO: document this
95 Cost cost = convertToReferenceCost( strict_dynamic_cast< ReferenceType * >( src )->base, dest, diff-1, indexer, env, func );
96 cost.incReference();
97 return cost;
98 } else if ( diff < -1 ) {
99 // TODO: document this
100 Cost cost = convertToReferenceCost( src, strict_dynamic_cast< ReferenceType * >( dest )->base, diff+1, indexer, env, func );
101 cost.incReference();
102 return cost;
103 } else if ( diff == 0 ) {
104 ReferenceType * srcAsRef = dynamic_cast< ReferenceType * >( src );
105 ReferenceType * destAsRef = dynamic_cast< ReferenceType * >( dest );
106 if ( srcAsRef && destAsRef ) { // pointer-like conversions between references
107 PRINT( std::cerr << "converting between references" << std::endl; )
108 Type::Qualifiers tq1 = srcAsRef->base->get_qualifiers();
109 Type::Qualifiers tq2 = destAsRef->base->get_qualifiers();
110 if ( tq1 <= tq2 && typesCompatibleIgnoreQualifiers( srcAsRef->base, destAsRef->base, indexer, env ) ) {
111 PRINT( std::cerr << " :: compatible and good qualifiers" << std::endl; )
112 if ( tq1 == tq2 ) {
113 // types are the same
114 return Cost::zero;
115 } else {
116 // types are the same, except otherPointer has more qualifiers
117 return Cost::safe;
118 }
119 } else { // xxx - this discards reference qualifiers from consideration -- reducing qualifiers is a safe conversion; is this right?
120 int assignResult = func( srcAsRef->base, destAsRef->base, indexer, env );
121 PRINT( std::cerr << "comparing references: " << assignResult << " " << srcAsRef << " " << destAsRef << std::endl; )
122 if ( assignResult > 0 ) {
123 return Cost::safe;
124 } else if ( assignResult < 0 ) {
125 return Cost::unsafe;
126 } // if
127 } // if
128 } else {
129 PRINT( std::cerr << "reference to rvalue conversion" << std::endl; )
130 PassVisitor<ConversionCost> converter( dest, indexer, env, conversionCost );
131 src->accept( converter );
132 return converter.pass.get_cost();
133 } // if
134 } else {
135 ReferenceType * destAsRef = dynamic_cast< ReferenceType * >( dest );
136 assert( diff == -1 && destAsRef );
137 PRINT( std::cerr << "dest is: " << dest << " / src is: " << src << std::endl; )
138 if ( typesCompatibleIgnoreQualifiers( src, destAsRef->base, indexer, env ) ) {
139 PRINT( std::cerr << "converting compatible base type" << std::endl; )
140 if ( src->get_lvalue() ) {
141 PRINT(
142 std::cerr << "lvalue to reference conversion" << std::endl;
143 std::cerr << src << " => " << destAsRef << std::endl;
144 )
145 // lvalue-to-reference conversion: cv lvalue T => cv T &
146 if ( src->get_qualifiers() == destAsRef->base->get_qualifiers() ) {
147 return Cost::reference; // cost needs to be non-zero to add cast
148 } if ( src->get_qualifiers() < destAsRef->base->get_qualifiers() ) {
149 return Cost::safe; // cost needs to be higher than previous cast to differentiate adding qualifiers vs. keeping same
150 } else {
151 return Cost::unsafe;
152 } // if
153 } else if ( destAsRef->base->get_const() ) {
154 PRINT( std::cerr << "rvalue to const ref conversion" << std::endl; )
155 // rvalue-to-const-reference conversion: T => const T &
156 return Cost::safe;
157 } else {
158 PRINT( std::cerr << "rvalue to non-const reference conversion" << std::endl; )
159 // rvalue-to-reference conversion: T => T &
160 return Cost::unsafe;
161 } // if
162 } // if
163 PRINT( std::cerr << "attempting to convert from incompatible base type -- fail" << std::endl; )
164 }
165 return Cost::infinity;
166 }
167
168 Cost convertToReferenceCost( Type * src, ReferenceType * dest, const SymTab::Indexer & indexer, const TypeEnvironment & env, PtrsFunction func ) {
169 int sdepth = src->referenceDepth(), ddepth = dest->referenceDepth();
170 Cost cost = convertToReferenceCost( src, dest, sdepth-ddepth, indexer, env, func );
171 PRINT( std::cerr << "convertToReferenceCost result: " << cost << std::endl; )
172 return cost;
173 }
174
175 ConversionCost::ConversionCost( Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env, CostFunction costFunc )
176 : dest( dest ), indexer( indexer ), cost( Cost::infinity ), env( env ), costFunc( costFunc ) {
177 }
178
179/*
180 Old
181 ===
182 Double
183 |
184 Float
185 |
186 ULong
187 / \
188 UInt Long
189 \ /
190 Int
191 |
192 Ushort
193 |
194 Short
195 |
196 Uchar
197 / \
198 Schar Char
199
200 New
201 ===
202 +-----LongDoubleComplex--+
203 LongDouble--+ | +-LongDoubleImag
204 | +---DoubleComplex---+ |
205 Double------+ | +----DoubleImag
206 | +-FloatComplex-+ |
207 Float---------+ +-------FloatImag
208 |
209 ULongLong
210 |
211 LongLong
212 |
213 ULong
214 / \
215 UInt Long
216 \ /
217 Int
218 |
219 Ushort
220 |
221 Short
222 |
223 Uchar
224 / \
225 Schar Char
226 \ /
227 Bool
228*/
229
230 static const int costMatrix[][ BasicType::NUMBER_OF_BASIC_TYPES ] = {
231 /* 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, F80, F128 */
232 /* Bool */ { 0, 1, 1, 2, 3, 4, 5, 6, 6, 7, 8, 9, 12, 13, 14, 12, 13, 14, -1, -1, -1, 10, 11, 14, 15},
233 /* Char */ { -1, 0, -1, 1, 2, 3, 4, 5, 5, 6, 7, 8, 11, 12, 13, 11, 12, 13, -1, -1, -1, 9, 10, 13, 14},
234 /* SChar */ { -1, -1, 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 11, 12, 13, 11, 12, 13, -1, -1, -1, 9, 10, 13, 14},
235 /* UChar */ { -1, -1, -1, 0, 1, 2, 3, 4, 4, 5, 6, 7, 10, 11, 12, 10, 11, 12, -1, -1, -1, 8, 9, 12, 13},
236 /* Short */ { -1, -1, -1, -1, 0, 1, 2, 3, 3, 4, 5, 6, 9, 10, 11, 9, 10, 11, -1, -1, -1, 7, 8, 11, 12},
237 /* UShort */{ -1, -1, -1, -1, -1, 0, 1, 2, 2, 3, 4, 5, 8, 9, 10, 8, 9, 10, -1, -1, -1, 6, 7, 10, 11},
238 /* Int */ { -1, -1, -1, -1, -1, -1, 0, 1, 1, 2, 3, 4, 7, 8, 9, 7, 8, 9, -1, -1, -1, 5, 6, 9, 10},
239 /* UInt */ { -1, -1, -1, -1, -1, -1, -1, 0, -1, 1, 2, 3, 6, 7, 8, 6, 7, 8, -1, -1, -1, 4, 5, 8, 9},
240 /* Long */ { -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 6, 7, 8, 6, 7, 8, -1, -1, -1, 4, 5, 8, 9},
241 /* ULong */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 5, 6, 7, 5, 6, 7, -1, -1, -1, 3, 4, 7, 8},
242 /* LLong */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 4, 5, 6, 4, 5, 6, -1, -1, -1, 2, 3, 6, 7},
243 /* ULLong */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 3, 4, 5, 3, 4, 5, -1, -1, -1, 1, 2, 5, 6},
244
245 /* Float */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 1, 2, 3, -1, -1, -1, -1, -1, 2, 3},
246 /* Double */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, -1, 1, 2, -1, -1, -1, -1, -1, 1, 2},
247 /* LDbl */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, -1, -1, 1, -1, -1, -1, -1, -1, -1, 1},
248 /* FCplex */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, -1, -1, -1, -1, -1, -1, -1},
249 /* DCplex */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, -1, -1, -1, -1, -1, -1, -1},
250 /* LDCplex */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, -1, -1, -1, -1, -1, -1, -1},
251 /* FImag */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, 3, 0, 1, 2, -1, -1, -1, -1},
252 /* DImag */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, -1, 0, 1, -1, -1, -1, -1},
253 /* LDImag */{ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 0, -1, -1, -1, -1},
254
255 /* I128 */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 2, 3, 4, 3, 4, 5, -1, -1, -1, 0, 1, 4, 4},
256 /* U128 */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, 3, 2, 3, 4, -1, -1, -1, -1, 0, 3, 3},
257
258 /* F80 */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 1, -1, -1, -1, -1, -1, 0, 1},
259 /* F128 */ { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, -1, 0},
260 };
261 static_assert(
262 sizeof(costMatrix)/sizeof(costMatrix[0][0]) == BasicType::NUMBER_OF_BASIC_TYPES*BasicType::NUMBER_OF_BASIC_TYPES,
263 "Each basic type kind should have a corresponding row in the cost matrix"
264 );
265
266
267 void ConversionCost::postvisit( VoidType * ) {
268 cost = Cost::infinity;
269 }
270
271 void ConversionCost::postvisit(BasicType *basicType) {
272 if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
273 int tableResult = costMatrix[ basicType->get_kind() ][ destAsBasic->get_kind() ];
274 if ( tableResult == -1 ) {
275 cost = Cost::unsafe;
276 } else {
277 cost = Cost::zero;
278 cost.incSafe( tableResult );
279 } // if
280 } else if ( dynamic_cast< EnumInstType *>( dest ) ) {
281 // xxx - not positive this is correct, but appears to allow casting int => enum
282 cost = Cost::unsafe;
283 } // if
284 // no cases for zero_t/one_t because it should not be possible to convert int, etc. to zero_t/one_t.
285 }
286
287 void ConversionCost::postvisit( PointerType * pointerType ) {
288 if ( PointerType *destAsPtr = dynamic_cast< PointerType* >( dest ) ) {
289 PRINT( std::cerr << pointerType << " ===> " << destAsPtr << std::endl; )
290 Type::Qualifiers tq1 = pointerType->base->get_qualifiers();
291 Type::Qualifiers tq2 = destAsPtr->base->get_qualifiers();
292 if ( tq1 <= tq2 && typesCompatibleIgnoreQualifiers( pointerType->base, destAsPtr->base, indexer, env ) ) {
293 PRINT( std::cerr << " :: compatible and good qualifiers" << std::endl; )
294 if ( tq1 == tq2 ) {
295 // types are the same
296 cost = Cost::zero;
297 } else {
298 // types are the same, except otherPointer has more qualifiers
299 cost = Cost::safe;
300 }
301 } else {
302 int assignResult = ptrsAssignable( pointerType->base, destAsPtr->base, env );
303 PRINT( std::cerr << " :: " << assignResult << std::endl; )
304 if ( assignResult > 0 && tq1 <= tq2 ) {
305 // 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?
306 if ( tq1 == tq2 ) {
307 cost = Cost::safe;
308 } else if ( tq1 < tq2 ) {
309 cost = Cost::safe+Cost::safe;
310 }
311 } else if ( assignResult < 0 ) {
312 cost = Cost::unsafe;
313 } // if
314 // assignResult == 0 means Cost::Infinity
315 } // if
316 // case case for zero_t because it should not be possible to convert pointers to zero_t.
317 } // if
318 }
319
320 void ConversionCost::postvisit( ArrayType * ) {}
321
322 void ConversionCost::postvisit( ReferenceType * refType ) {
323 // Note: dest can never be a reference, since it would have been caught in an earlier check
324 assert( ! dynamic_cast< ReferenceType * >( dest ) );
325 // convert reference to rvalue: cv T1 & => T2
326 // recursively compute conversion cost from T1 to T2.
327 // cv can be safely dropped because of 'implicit dereference' behavior.
328 cost = costFunc( refType->base, dest, indexer, env );
329 if ( refType->base->get_qualifiers() == dest->get_qualifiers() ) {
330 cost.incReference(); // prefer exact qualifiers
331 } else if ( refType->base->get_qualifiers() < dest->get_qualifiers() ) {
332 cost.incSafe(); // then gaining qualifiers
333 } else {
334 cost.incUnsafe(); // lose qualifiers as last resort
335 }
336 PRINT( std::cerr << refType << " ==> " << dest << " " << cost << std::endl; )
337 }
338
339 void ConversionCost::postvisit( FunctionType * ) {}
340
341 void ConversionCost::postvisit( StructInstType * inst ) {
342 if ( StructInstType *destAsInst = dynamic_cast< StructInstType* >( dest ) ) {
343 if ( inst->name == destAsInst->name ) {
344 cost = Cost::zero;
345 } // if
346 } // if
347 }
348
349 void ConversionCost::postvisit( UnionInstType * inst ) {
350 if ( UnionInstType *destAsInst = dynamic_cast< UnionInstType* >( dest ) ) {
351 if ( inst->name == destAsInst->name ) {
352 cost = Cost::zero;
353 } // if
354 } // if
355 }
356
357 void ConversionCost::postvisit( EnumInstType * ) {
358 static Type::Qualifiers q;
359 static BasicType integer( q, BasicType::SignedInt );
360 cost = costFunc( &integer, dest, indexer, env ); // safe if dest >= int
361 if ( cost < Cost::unsafe ) {
362 cost.incSafe();
363 } // if
364 }
365
366 void ConversionCost::postvisit( TraitInstType * ) {}
367
368 void ConversionCost::postvisit( TypeInstType *inst ) {
369 if ( const EqvClass *eqvClass = env.lookup( inst->name ) ) {
370 cost = costFunc( eqvClass->type, dest, indexer, env );
371 } else if ( TypeInstType *destAsInst = dynamic_cast< TypeInstType* >( dest ) ) {
372 if ( inst->name == destAsInst->name ) {
373 cost = Cost::zero;
374 }
375 } else if ( NamedTypeDecl *namedType = indexer.lookupType( inst->name ) ) {
376 TypeDecl *type = dynamic_cast< TypeDecl* >( namedType );
377 // all typedefs should be gone by this point
378 assert( type );
379 if ( type->base ) {
380 cost = costFunc( type->base, dest, indexer, env ) + Cost::safe;
381 } // if
382 } // if
383 }
384
385 void ConversionCost::postvisit( TupleType * tupleType ) {
386 Cost c = Cost::zero;
387 if ( TupleType * destAsTuple = dynamic_cast< TupleType * >( dest ) ) {
388 std::list< Type * >::const_iterator srcIt = tupleType->types.begin();
389 std::list< Type * >::const_iterator destIt = destAsTuple->types.begin();
390 while ( srcIt != tupleType->types.end() && destIt != destAsTuple->types.end() ) {
391 Cost newCost = costFunc( *srcIt++, *destIt++, indexer, env );
392 if ( newCost == Cost::infinity ) {
393 return;
394 } // if
395 c += newCost;
396 } // while
397 if ( destIt != destAsTuple->types.end() ) {
398 cost = Cost::infinity;
399 } else {
400 cost = c;
401 } // if
402 } // if
403 }
404
405 void ConversionCost::postvisit( VarArgsType * ) {
406 if ( dynamic_cast< VarArgsType* >( dest ) ) {
407 cost = Cost::zero;
408 }
409 }
410
411 void ConversionCost::postvisit( ZeroType * ) {
412 if ( dynamic_cast< ZeroType * >( dest ) ) {
413 cost = Cost::zero;
414 } else if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
415 // copied from visit(BasicType*) for signed int, but +1 for safe conversions
416 int tableResult = costMatrix[ BasicType::SignedInt ][ destAsBasic->get_kind() ];
417 if ( tableResult == -1 ) {
418 cost = Cost::unsafe;
419 } else {
420 cost = Cost::zero;
421 cost.incSafe( tableResult + 1 );
422 }
423 } else if ( dynamic_cast< PointerType* >( dest ) ) {
424 cost = Cost::safe;
425 }
426 }
427
428 void ConversionCost::postvisit( OneType * ) {
429 if ( dynamic_cast< OneType * >( dest ) ) {
430 cost = Cost::zero;
431 } else if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
432 // copied from visit(BasicType*) for signed int, but +1 for safe conversions
433 int tableResult = costMatrix[ BasicType::SignedInt ][ destAsBasic->get_kind() ];
434 if ( tableResult == -1 ) {
435 cost = Cost::unsafe;
436 } else {
437 cost = Cost::zero;
438 cost.incSafe( tableResult + 1 );
439 }
440 }
441 }
442} // namespace ResolvExpr
443
444// Local Variables: //
445// tab-width: 4 //
446// mode: c++ //
447// compile-command: "make install" //
448// End: //
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