source: src/ResolvExpr/ConversionCost.cc@ 184557e

new-env
Last change on this file since 184557e was b21c77a, checked in by Aaron Moss <a3moss@…>, 7 years ago

Merge remote-tracking branch 'origin/with_gc' into new-env
  • Property mode set to 100644
File size: 19.1 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 "Common/GC.h" // for new_static_root
23#include "ResolvExpr/Cost.h" // for Cost
24#include "ResolvExpr/TypeEnvironment.h" // for ClassRef, TypeEnvironment
25#include "SymTab/Indexer.h" // for Indexer
26#include "SynTree/Declaration.h" // for TypeDecl, NamedTypeDecl
27#include "SynTree/Type.h" // for Type, BasicType, TypeInstType
28#include "typeops.h" // for typesCompatibleIgnoreQualifiers
29
30namespace ResolvExpr {
31 const Cost Cost::zero = Cost{ 0, 0, 0, 0, 0, 0 };
32 const Cost Cost::infinity = Cost{ -1, -1, -1, 1, -1, -1 };
33 const Cost Cost::unsafe = Cost{ 1, 0, 0, 0, 0, 0 };
34 const Cost Cost::poly = Cost{ 0, 1, 0, 0, 0, 0 };
35 const Cost Cost::var = Cost{ 0, 0, 1, 0, 0, 0 };
36 const Cost Cost::spec = Cost{ 0, 0, 0, -1, 0, 0 };
37 const Cost Cost::safe = Cost{ 0, 0, 0, 0, 1, 0 };
38 const Cost Cost::reference = Cost{ 0, 0, 0, 0, 0, 1 };
39
40#if 0
41#define PRINT(x) x
42#else
43#define PRINT(x)
44#endif
45 Cost conversionCost( Type *src, Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env ) {
46 if ( TypeInstType *destAsTypeInst = dynamic_cast< TypeInstType* >( dest ) ) {
47 PRINT( std::cerr << "type inst " << destAsTypeInst->name; )
48 if ( ClassRef eqvClass = env.lookup( destAsTypeInst->name ) ) {
49 if ( Type* boundTy = eqvClass.get_bound().type ) {
50 return conversionCost( src, boundTy, indexer, env );
51 } else {
52 return Cost::infinity;
53 }
54 } else if ( NamedTypeDecl *namedType = indexer.lookupType( destAsTypeInst->name ) ) {
55 PRINT( std::cerr << " found" << std::endl; )
56 TypeDecl *type = dynamic_cast< TypeDecl* >( namedType );
57 // all typedefs should be gone by this point
58 assert( type );
59 if ( type->base ) {
60 return conversionCost( src, type->base, indexer, env ) + Cost::safe;
61 } // if
62 } // if
63 PRINT( std::cerr << " not found" << std::endl; )
64 } // if
65 PRINT(
66 std::cerr << "src is ";
67 src->print( std::cerr );
68 std::cerr << std::endl << "dest is ";
69 dest->print( std::cerr );
70 std::cerr << std::endl << "env is" << std::endl;
71 env.print( std::cerr, 8 );
72 )
73 if ( typesCompatibleIgnoreQualifiers( src, dest, indexer, env ) ) {
74 PRINT( std::cerr << "compatible!" << std::endl; )
75 return Cost::zero;
76 } else if ( dynamic_cast< VoidType* >( dest ) ) {
77 return Cost::safe;
78 } else if ( ReferenceType * refType = dynamic_cast< ReferenceType * > ( dest ) ) {
79 PRINT( std::cerr << "conversionCost: dest is reference" << std::endl; )
80 return convertToReferenceCost( src, refType, indexer, env, [](Type * t1, Type * t2, const SymTab::Indexer &, const TypeEnvironment & env ){
81 return ptrsAssignable( t1, t2, env );
82 });
83 } else {
84 PassVisitor<ConversionCost> converter( dest, indexer, env, conversionCost );
85 src->accept( converter );
86 if ( converter.pass.get_cost() == Cost::infinity ) {
87 return Cost::infinity;
88 } else {
89 return converter.pass.get_cost() + Cost::zero;
90 } // if
91 } // if
92 }
93
94 Cost convertToReferenceCost( Type * src, Type * dest, int diff, const SymTab::Indexer & indexer, const TypeEnvironment & env, PtrsFunction func ) {
95 PRINT( std::cerr << "convert to reference cost... diff " << diff << " " << src << " / " << dest << std::endl; )
96 if ( diff > 0 ) {
97 // TODO: document this
98 Cost cost = convertToReferenceCost( strict_dynamic_cast< ReferenceType * >( src )->base, dest, diff-1, indexer, env, func );
99 cost.incReference();
100 return cost;
101 } else if ( diff < -1 ) {
102 // TODO: document this
103 Cost cost = convertToReferenceCost( src, strict_dynamic_cast< ReferenceType * >( dest )->base, diff+1, indexer, env, func );
104 cost.incReference();
105 return cost;
106 } else if ( diff == 0 ) {
107 ReferenceType * srcAsRef = dynamic_cast< ReferenceType * >( src );
108 ReferenceType * destAsRef = dynamic_cast< ReferenceType * >( dest );
109 if ( srcAsRef && destAsRef ) { // pointer-like conversions between references
110 PRINT( std::cerr << "converting between references" << std::endl; )
111 Type::Qualifiers tq1 = srcAsRef->base->get_qualifiers();
112 Type::Qualifiers tq2 = destAsRef->base->get_qualifiers();
113 if ( tq1 <= tq2 && typesCompatibleIgnoreQualifiers( srcAsRef->base, destAsRef->base, indexer, env ) ) {
114 PRINT( std::cerr << " :: compatible and good qualifiers" << std::endl; )
115 if ( tq1 == tq2 ) {
116 // types are the same
117 return Cost::zero;
118 } else {
119 // types are the same, except otherPointer has more qualifiers
120 return Cost::safe;
121 }
122 } else { // xxx - this discards reference qualifiers from consideration -- reducing qualifiers is a safe conversion; is this right?
123 int assignResult = func( srcAsRef->base, destAsRef->base, indexer, env );
124 PRINT( std::cerr << "comparing references: " << assignResult << " " << srcAsRef << " " << destAsRef << std::endl; )
125 if ( assignResult > 0 ) {
126 return Cost::safe;
127 } else if ( assignResult < 0 ) {
128 return Cost::unsafe;
129 } // if
130 } // if
131 } else {
132 PRINT( std::cerr << "reference to rvalue conversion" << std::endl; )
133 PassVisitor<ConversionCost> converter( dest, indexer, env, conversionCost );
134 src->accept( converter );
135 return converter.pass.get_cost();
136 } // if
137 } else {
138 ReferenceType * destAsRef = dynamic_cast< ReferenceType * >( dest );
139 assert( diff == -1 && destAsRef );
140 PRINT( std::cerr << "dest is: " << dest << " / src is: " << src << std::endl; )
141 if ( typesCompatibleIgnoreQualifiers( src, destAsRef->base, indexer, env ) ) {
142 PRINT( std::cerr << "converting compatible base type" << std::endl; )
143 if ( src->get_lvalue() ) {
144 PRINT(
145 std::cerr << "lvalue to reference conversion" << std::endl;
146 std::cerr << src << " => " << destAsRef << std::endl;
147 )
148 // lvalue-to-reference conversion: cv lvalue T => cv T &
149 if ( src->get_qualifiers() == destAsRef->base->get_qualifiers() ) {
150 return Cost::reference; // cost needs to be non-zero to add cast
151 } if ( src->get_qualifiers() < destAsRef->base->get_qualifiers() ) {
152 return Cost::safe; // cost needs to be higher than previous cast to differentiate adding qualifiers vs. keeping same
153 } else {
154 return Cost::unsafe;
155 } // if
156 } else if ( destAsRef->base->get_const() ) {
157 PRINT( std::cerr << "rvalue to const ref conversion" << std::endl; )
158 // rvalue-to-const-reference conversion: T => const T &
159 return Cost::safe;
160 } else {
161 PRINT( std::cerr << "rvalue to non-const reference conversion" << std::endl; )
162 // rvalue-to-reference conversion: T => T &
163 return Cost::unsafe;
164 } // if
165 } // if
166 PRINT( std::cerr << "attempting to convert from incompatible base type -- fail" << std::endl; )
167 }
168 return Cost::infinity;
169 }
170
171 Cost convertToReferenceCost( Type * src, ReferenceType * dest, const SymTab::Indexer & indexer, const TypeEnvironment & env, PtrsFunction func ) {
172 int sdepth = src->referenceDepth(), ddepth = dest->referenceDepth();
173 Cost cost = convertToReferenceCost( src, dest, sdepth-ddepth, indexer, env, func );
174 PRINT( std::cerr << "convertToReferenceCost result: " << cost << std::endl; )
175 return cost;
176 }
177
178 ConversionCost::ConversionCost( Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env, CostFunction costFunc )
179 : dest( dest ), indexer( indexer ), cost( Cost::infinity ), env( env ), costFunc( costFunc ) {
180 }
181
182/*
183 Old
184 ===
185 Double
186 |
187 Float
188 |
189 ULong
190 / \
191 UInt Long
192 \ /
193 Int
194 |
195 Ushort
196 |
197 Short
198 |
199 Uchar
200 / \
201 Schar Char
202
203 New
204 ===
205 +-----LongDoubleComplex--+
206 LongDouble--+ | +-LongDoubleImag
207 | +---DoubleComplex---+ |
208 Double------+ | +----DoubleImag
209 | +-FloatComplex-+ |
210 Float---------+ +-------FloatImag
211 |
212 ULongLong
213 |
214 LongLong
215 |
216 ULong
217 / \
218 UInt Long
219 \ /
220 Int
221 |
222 Ushort
223 |
224 Short
225 |
226 Uchar
227 / \
228 Schar Char
229 \ /
230 Bool
231*/
232
233 static const int costMatrix[][ BasicType::NUMBER_OF_BASIC_TYPES ] = {
234 /* 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 */
235 /* 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},
236 /* 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},
237 /* 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},
238 /* 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},
239 /* 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},
240 /* 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},
241 /* 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},
242 /* 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},
243 /* 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},
244 /* 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},
245 /* 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},
246 /* 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},
247
248 /* 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},
249 /* 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},
250 /* 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},
251 /* 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},
252 /* 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},
253 /* 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},
254 /* 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},
255 /* 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},
256 /* 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},
257
258 /* 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},
259 /* 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},
260
261 /* 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},
262 /* 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},
263 };
264 static_assert(
265 sizeof(costMatrix)/sizeof(costMatrix[0][0]) == BasicType::NUMBER_OF_BASIC_TYPES*BasicType::NUMBER_OF_BASIC_TYPES,
266 "Each basic type kind should have a corresponding row in the cost matrix"
267 );
268
269
270 void ConversionCost::postvisit( VoidType * ) {
271 cost = Cost::infinity;
272 }
273
274 void ConversionCost::postvisit(BasicType *basicType) {
275 if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
276 int tableResult = costMatrix[ basicType->get_kind() ][ destAsBasic->get_kind() ];
277 if ( tableResult == -1 ) {
278 cost = Cost::unsafe;
279 } else {
280 cost = Cost::zero;
281 cost.incSafe( tableResult );
282 } // if
283 } else if ( dynamic_cast< EnumInstType *>( dest ) ) {
284 // xxx - not positive this is correct, but appears to allow casting int => enum
285 cost = Cost::unsafe;
286 } // if
287 // no cases for zero_t/one_t because it should not be possible to convert int, etc. to zero_t/one_t.
288 }
289
290 void ConversionCost::postvisit( PointerType * pointerType ) {
291 if ( PointerType *destAsPtr = dynamic_cast< PointerType* >( dest ) ) {
292 PRINT( std::cerr << pointerType << " ===> " << destAsPtr << std::endl; )
293 Type::Qualifiers tq1 = pointerType->base->get_qualifiers();
294 Type::Qualifiers tq2 = destAsPtr->base->get_qualifiers();
295 if ( tq1 <= tq2 && typesCompatibleIgnoreQualifiers( pointerType->base, destAsPtr->base, indexer, env ) ) {
296 PRINT( std::cerr << " :: compatible and good qualifiers" << std::endl; )
297 if ( tq1 == tq2 ) {
298 // types are the same
299 cost = Cost::zero;
300 } else {
301 // types are the same, except otherPointer has more qualifiers
302 cost = Cost::safe;
303 }
304 } else {
305 int assignResult = ptrsAssignable( pointerType->base, destAsPtr->base, env );
306 PRINT( std::cerr << " :: " << assignResult << std::endl; )
307 if ( assignResult > 0 && tq1 <= tq2 ) {
308 // 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?
309 if ( tq1 == tq2 ) {
310 cost = Cost::safe;
311 } else if ( tq1 < tq2 ) {
312 cost = Cost::safe+Cost::safe;
313 }
314 } else if ( assignResult < 0 ) {
315 cost = Cost::unsafe;
316 } // if
317 // assignResult == 0 means Cost::Infinity
318 } // if
319 // case case for zero_t because it should not be possible to convert pointers to zero_t.
320 } // if
321 }
322
323 void ConversionCost::postvisit( ArrayType * ) {}
324
325 void ConversionCost::postvisit( ReferenceType * refType ) {
326 // Note: dest can never be a reference, since it would have been caught in an earlier check
327 assert( ! dynamic_cast< ReferenceType * >( dest ) );
328 // convert reference to rvalue: cv T1 & => T2
329 // recursively compute conversion cost from T1 to T2.
330 // cv can be safely dropped because of 'implicit dereference' behavior.
331 cost = costFunc( refType->base, dest, indexer, env );
332 if ( refType->base->get_qualifiers() == dest->get_qualifiers() ) {
333 cost.incReference(); // prefer exact qualifiers
334 } else if ( refType->base->get_qualifiers() < dest->get_qualifiers() ) {
335 cost.incSafe(); // then gaining qualifiers
336 } else {
337 cost.incUnsafe(); // lose qualifiers as last resort
338 }
339 PRINT( std::cerr << refType << " ==> " << dest << " " << cost << std::endl; )
340 }
341
342 void ConversionCost::postvisit( FunctionType * ) {}
343
344 void ConversionCost::postvisit( StructInstType * inst ) {
345 if ( StructInstType *destAsInst = dynamic_cast< StructInstType* >( dest ) ) {
346 if ( inst->name == destAsInst->name ) {
347 cost = Cost::zero;
348 } // if
349 } // if
350 }
351
352 void ConversionCost::postvisit( UnionInstType * inst ) {
353 if ( UnionInstType *destAsInst = dynamic_cast< UnionInstType* >( dest ) ) {
354 if ( inst->name == destAsInst->name ) {
355 cost = Cost::zero;
356 } // if
357 } // if
358 }
359
360 void ConversionCost::postvisit( EnumInstType * ) {
361 static Type::Qualifiers q;
362 static BasicType* integer = new_static_root<BasicType>( q, BasicType::SignedInt );
363 cost = costFunc( integer, dest, indexer, env ); // safe if dest >= int
364 if ( cost < Cost::unsafe ) {
365 cost.incSafe();
366 } // if
367 }
368
369 void ConversionCost::postvisit( TraitInstType * ) {}
370
371 void ConversionCost::postvisit( TypeInstType *inst ) {
372 if ( ClassRef eqvClass = env.lookup( inst->name ) ) {
373 cost = costFunc( eqvClass.get_bound().type, dest, indexer, env );
374 } else if ( TypeInstType *destAsInst = dynamic_cast< TypeInstType* >( dest ) ) {
375 if ( inst->name == destAsInst->name ) {
376 cost = Cost::zero;
377 }
378 } else if ( NamedTypeDecl *namedType = indexer.lookupType( inst->name ) ) {
379 TypeDecl *type = dynamic_cast< TypeDecl* >( namedType );
380 // all typedefs should be gone by this point
381 assert( type );
382 if ( type->base ) {
383 cost = costFunc( type->base, dest, indexer, env ) + Cost::safe;
384 } // if
385 } // if
386 }
387
388 void ConversionCost::postvisit( TupleType * tupleType ) {
389 Cost c = Cost::zero;
390 if ( TupleType * destAsTuple = dynamic_cast< TupleType * >( dest ) ) {
391 std::list< Type * >::const_iterator srcIt = tupleType->types.begin();
392 std::list< Type * >::const_iterator destIt = destAsTuple->types.begin();
393 while ( srcIt != tupleType->types.end() && destIt != destAsTuple->types.end() ) {
394 Cost newCost = costFunc( *srcIt++, *destIt++, indexer, env );
395 if ( newCost == Cost::infinity ) {
396 return;
397 } // if
398 c += newCost;
399 } // while
400 if ( destIt != destAsTuple->types.end() ) {
401 cost = Cost::infinity;
402 } else {
403 cost = c;
404 } // if
405 } // if
406 }
407
408 void ConversionCost::postvisit( VarArgsType * ) {
409 if ( dynamic_cast< VarArgsType* >( dest ) ) {
410 cost = Cost::zero;
411 }
412 }
413
414 void ConversionCost::postvisit( ZeroType * ) {
415 if ( dynamic_cast< ZeroType * >( dest ) ) {
416 cost = Cost::zero;
417 } else if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
418 // copied from visit(BasicType*) for signed int, but +1 for safe conversions
419 int tableResult = costMatrix[ BasicType::SignedInt ][ destAsBasic->get_kind() ];
420 if ( tableResult == -1 ) {
421 cost = Cost::unsafe;
422 } else {
423 cost = Cost::zero;
424 cost.incSafe( tableResult + 1 );
425 }
426 } else if ( dynamic_cast< PointerType* >( dest ) ) {
427 cost = Cost::safe;
428 }
429 }
430
431 void ConversionCost::postvisit( OneType * ) {
432 if ( dynamic_cast< OneType * >( dest ) ) {
433 cost = Cost::zero;
434 } else if ( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
435 // copied from visit(BasicType*) for signed int, but +1 for safe conversions
436 int tableResult = costMatrix[ BasicType::SignedInt ][ destAsBasic->get_kind() ];
437 if ( tableResult == -1 ) {
438 cost = Cost::unsafe;
439 } else {
440 cost = Cost::zero;
441 cost.incSafe( tableResult + 1 );
442 }
443 }
444 }
445} // namespace ResolvExpr
446
447// Local Variables: //
448// tab-width: 4 //
449// mode: c++ //
450// compile-command: "make install" //
451// End: //
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