John McCall | 7d384dd | 2009-11-18 07:57:50 +0000 | [diff] [blame] | 1 | //===--- Lookup.h - Classes for name lookup ---------------------*- C++ -*-===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This file defines the LookupResult class, which is integral to |
| 11 | // Sema's name-lookup subsystem. |
| 12 | // |
| 13 | //===----------------------------------------------------------------------===// |
| 14 | |
| 15 | #ifndef LLVM_CLANG_SEMA_LOOKUP_H |
| 16 | #define LLVM_CLANG_SEMA_LOOKUP_H |
| 17 | |
| 18 | #include "Sema.h" |
| 19 | |
| 20 | namespace clang { |
| 21 | |
| 22 | /// @brief Represents the results of name lookup. |
| 23 | /// |
| 24 | /// An instance of the LookupResult class captures the results of a |
| 25 | /// single name lookup, which can return no result (nothing found), |
| 26 | /// a single declaration, a set of overloaded functions, or an |
| 27 | /// ambiguity. Use the getKind() method to determine which of these |
| 28 | /// results occurred for a given lookup. |
| 29 | /// |
| 30 | /// Any non-ambiguous lookup can be converted into a single |
| 31 | /// (possibly NULL) @c NamedDecl* via the getAsSingleDecl() method. |
| 32 | /// This permits the common-case usage in C and Objective-C where |
| 33 | /// name lookup will always return a single declaration. Use of |
| 34 | /// this is largely deprecated; callers should handle the possibility |
| 35 | /// of multiple declarations. |
| 36 | class LookupResult { |
| 37 | public: |
| 38 | enum LookupResultKind { |
| 39 | /// @brief No entity found met the criteria. |
| 40 | NotFound = 0, |
| 41 | |
| 42 | /// @brief Name lookup found a single declaration that met the |
| 43 | /// criteria. getAsDecl will return this declaration. |
| 44 | Found, |
| 45 | |
| 46 | /// @brief Name lookup found a set of overloaded functions that |
| 47 | /// met the criteria. getAsDecl will turn this set of overloaded |
| 48 | /// functions into an OverloadedFunctionDecl. |
| 49 | FoundOverloaded, |
| 50 | |
| 51 | /// @brief Name lookup found an unresolvable value declaration |
| 52 | /// and cannot yet complete. This only happens in C++ dependent |
| 53 | /// contexts with dependent using declarations. |
| 54 | FoundUnresolvedValue, |
| 55 | |
| 56 | /// @brief Name lookup results in an ambiguity; use |
| 57 | /// getAmbiguityKind to figure out what kind of ambiguity |
| 58 | /// we have. |
| 59 | Ambiguous |
| 60 | }; |
| 61 | |
| 62 | enum AmbiguityKind { |
| 63 | /// Name lookup results in an ambiguity because multiple |
| 64 | /// entities that meet the lookup criteria were found in |
| 65 | /// subobjects of different types. For example: |
| 66 | /// @code |
| 67 | /// struct A { void f(int); } |
| 68 | /// struct B { void f(double); } |
| 69 | /// struct C : A, B { }; |
| 70 | /// void test(C c) { |
| 71 | /// c.f(0); // error: A::f and B::f come from subobjects of different |
| 72 | /// // types. overload resolution is not performed. |
| 73 | /// } |
| 74 | /// @endcode |
| 75 | AmbiguousBaseSubobjectTypes, |
| 76 | |
| 77 | /// Name lookup results in an ambiguity because multiple |
| 78 | /// nonstatic entities that meet the lookup criteria were found |
| 79 | /// in different subobjects of the same type. For example: |
| 80 | /// @code |
| 81 | /// struct A { int x; }; |
| 82 | /// struct B : A { }; |
| 83 | /// struct C : A { }; |
| 84 | /// struct D : B, C { }; |
| 85 | /// int test(D d) { |
| 86 | /// return d.x; // error: 'x' is found in two A subobjects (of B and C) |
| 87 | /// } |
| 88 | /// @endcode |
| 89 | AmbiguousBaseSubobjects, |
| 90 | |
| 91 | /// Name lookup results in an ambiguity because multiple definitions |
| 92 | /// of entity that meet the lookup criteria were found in different |
| 93 | /// declaration contexts. |
| 94 | /// @code |
| 95 | /// namespace A { |
| 96 | /// int i; |
| 97 | /// namespace B { int i; } |
| 98 | /// int test() { |
| 99 | /// using namespace B; |
| 100 | /// return i; // error 'i' is found in namespace A and A::B |
| 101 | /// } |
| 102 | /// } |
| 103 | /// @endcode |
| 104 | AmbiguousReference, |
| 105 | |
| 106 | /// Name lookup results in an ambiguity because an entity with a |
| 107 | /// tag name was hidden by an entity with an ordinary name from |
| 108 | /// a different context. |
| 109 | /// @code |
| 110 | /// namespace A { struct Foo {}; } |
| 111 | /// namespace B { void Foo(); } |
| 112 | /// namespace C { |
| 113 | /// using namespace A; |
| 114 | /// using namespace B; |
| 115 | /// } |
| 116 | /// void test() { |
| 117 | /// C::Foo(); // error: tag 'A::Foo' is hidden by an object in a |
| 118 | /// // different namespace |
| 119 | /// } |
| 120 | /// @endcode |
| 121 | AmbiguousTagHiding |
| 122 | }; |
| 123 | |
| 124 | /// A little identifier for flagging temporary lookup results. |
| 125 | enum TemporaryToken { |
| 126 | Temporary |
| 127 | }; |
| 128 | |
| 129 | typedef llvm::SmallVector<NamedDecl*, 4> DeclsTy; |
| 130 | typedef DeclsTy::const_iterator iterator; |
| 131 | |
| 132 | LookupResult(Sema &SemaRef, DeclarationName Name, SourceLocation NameLoc, |
| 133 | Sema::LookupNameKind LookupKind, |
| 134 | Sema::RedeclarationKind Redecl = Sema::NotForRedeclaration) |
| 135 | : ResultKind(NotFound), |
| 136 | Paths(0), |
| 137 | SemaRef(SemaRef), |
| 138 | Name(Name), |
| 139 | NameLoc(NameLoc), |
| 140 | LookupKind(LookupKind), |
| 141 | IDNS(0), |
| 142 | Redecl(Redecl != Sema::NotForRedeclaration), |
| 143 | HideTags(true), |
| 144 | Diagnose(Redecl == Sema::NotForRedeclaration) |
| 145 | {} |
| 146 | |
| 147 | /// Creates a temporary lookup result, initializing its core data |
| 148 | /// using the information from another result. Diagnostics are always |
| 149 | /// disabled. |
| 150 | LookupResult(TemporaryToken _, const LookupResult &Other) |
| 151 | : ResultKind(NotFound), |
| 152 | Paths(0), |
| 153 | SemaRef(Other.SemaRef), |
| 154 | Name(Other.Name), |
| 155 | NameLoc(Other.NameLoc), |
| 156 | LookupKind(Other.LookupKind), |
| 157 | IDNS(Other.IDNS), |
| 158 | Redecl(Other.Redecl), |
| 159 | HideTags(Other.HideTags), |
| 160 | Diagnose(false) |
| 161 | {} |
| 162 | |
| 163 | ~LookupResult() { |
| 164 | if (Diagnose) diagnose(); |
| 165 | if (Paths) deletePaths(Paths); |
| 166 | } |
| 167 | |
| 168 | /// Gets the name to look up. |
| 169 | DeclarationName getLookupName() const { |
| 170 | return Name; |
| 171 | } |
| 172 | |
| 173 | /// Gets the kind of lookup to perform. |
| 174 | Sema::LookupNameKind getLookupKind() const { |
| 175 | return LookupKind; |
| 176 | } |
| 177 | |
| 178 | /// True if this lookup is just looking for an existing declaration. |
| 179 | bool isForRedeclaration() const { |
| 180 | return Redecl; |
| 181 | } |
| 182 | |
| 183 | /// Sets whether tag declarations should be hidden by non-tag |
| 184 | /// declarations during resolution. The default is true. |
| 185 | void setHideTags(bool Hide) { |
| 186 | HideTags = Hide; |
| 187 | } |
| 188 | |
| 189 | /// The identifier namespace of this lookup. This information is |
| 190 | /// private to the lookup routines. |
| 191 | unsigned getIdentifierNamespace() const { |
| 192 | assert(IDNS); |
| 193 | return IDNS; |
| 194 | } |
| 195 | |
| 196 | void setIdentifierNamespace(unsigned NS) { |
| 197 | IDNS = NS; |
| 198 | } |
| 199 | |
| 200 | bool isAmbiguous() const { |
| 201 | return getResultKind() == Ambiguous; |
| 202 | } |
| 203 | |
John McCall | 6826314 | 2009-11-18 22:49:29 +0000 | [diff] [blame^] | 204 | /// Determines if this names a single result which is not an |
| 205 | /// unresolved value using decl. If so, it is safe to call |
| 206 | /// getFoundDecl(). |
| 207 | bool isSingleResult() const { |
| 208 | return getResultKind() == Found; |
| 209 | } |
| 210 | |
John McCall | 7d384dd | 2009-11-18 07:57:50 +0000 | [diff] [blame] | 211 | LookupResultKind getResultKind() const { |
| 212 | sanity(); |
| 213 | return ResultKind; |
| 214 | } |
| 215 | |
| 216 | AmbiguityKind getAmbiguityKind() const { |
| 217 | assert(isAmbiguous()); |
| 218 | return Ambiguity; |
| 219 | } |
| 220 | |
| 221 | iterator begin() const { return Decls.begin(); } |
| 222 | iterator end() const { return Decls.end(); } |
| 223 | |
| 224 | /// \brief Return true if no decls were found |
| 225 | bool empty() const { return Decls.empty(); } |
| 226 | |
| 227 | /// \brief Return the base paths structure that's associated with |
| 228 | /// these results, or null if none is. |
| 229 | CXXBasePaths *getBasePaths() const { |
| 230 | return Paths; |
| 231 | } |
| 232 | |
| 233 | /// \brief Add a declaration to these results. |
| 234 | void addDecl(NamedDecl *D) { |
| 235 | Decls.push_back(D); |
| 236 | ResultKind = Found; |
| 237 | } |
| 238 | |
| 239 | /// \brief Add all the declarations from another set of lookup |
| 240 | /// results. |
| 241 | void addAllDecls(const LookupResult &Other) { |
| 242 | Decls.append(Other.begin(), Other.end()); |
| 243 | ResultKind = Found; |
| 244 | } |
| 245 | |
| 246 | /// \brief Hides a set of declarations. |
| 247 | template <class NamedDeclSet> void hideDecls(const NamedDeclSet &Set) { |
| 248 | unsigned I = 0, N = Decls.size(); |
| 249 | while (I < N) { |
| 250 | if (Set.count(Decls[I])) |
| 251 | Decls[I] = Decls[--N]; |
| 252 | else |
| 253 | I++; |
| 254 | } |
| 255 | Decls.set_size(N); |
| 256 | } |
| 257 | |
John McCall | 6826314 | 2009-11-18 22:49:29 +0000 | [diff] [blame^] | 258 | /// \brief Resolves the result kind of the lookup, possibly hiding |
| 259 | /// decls. |
John McCall | 7d384dd | 2009-11-18 07:57:50 +0000 | [diff] [blame] | 260 | /// |
| 261 | /// This should be called in any environment where lookup might |
| 262 | /// generate multiple lookup results. |
| 263 | void resolveKind(); |
| 264 | |
John McCall | 6826314 | 2009-11-18 22:49:29 +0000 | [diff] [blame^] | 265 | /// \brief Re-resolves the result kind of the lookup after a set of |
| 266 | /// removals has been performed. |
| 267 | void resolveKindAfterFilter() { |
| 268 | if (Decls.empty()) |
| 269 | ResultKind = NotFound; |
| 270 | else { |
| 271 | ResultKind = Found; |
| 272 | resolveKind(); |
| 273 | } |
| 274 | } |
| 275 | |
John McCall | 7d384dd | 2009-11-18 07:57:50 +0000 | [diff] [blame] | 276 | /// \brief Fetch this as an unambiguous single declaration |
| 277 | /// (possibly an overloaded one). |
| 278 | /// |
| 279 | /// This is deprecated; users should be written to handle |
| 280 | /// ambiguous and overloaded lookups. |
| 281 | NamedDecl *getAsSingleDecl(ASTContext &Context) const; |
| 282 | |
| 283 | /// \brief Fetch the unique decl found by this lookup. Asserts |
| 284 | /// that one was found. |
| 285 | /// |
| 286 | /// This is intended for users who have examined the result kind |
| 287 | /// and are certain that there is only one result. |
| 288 | NamedDecl *getFoundDecl() const { |
| 289 | assert(getResultKind() == Found |
| 290 | && "getFoundDecl called on non-unique result"); |
| 291 | return Decls[0]->getUnderlyingDecl(); |
| 292 | } |
| 293 | |
John McCall | 6826314 | 2009-11-18 22:49:29 +0000 | [diff] [blame^] | 294 | /// Fetches a representative decl. Useful for lazy diagnostics. |
| 295 | NamedDecl *getRepresentativeDecl() const { |
| 296 | assert(!Decls.empty() && "cannot get representative of empty set"); |
| 297 | return Decls[0]; |
| 298 | } |
| 299 | |
John McCall | 7d384dd | 2009-11-18 07:57:50 +0000 | [diff] [blame] | 300 | /// \brief Asks if the result is a single tag decl. |
| 301 | bool isSingleTagDecl() const { |
| 302 | return getResultKind() == Found && isa<TagDecl>(getFoundDecl()); |
| 303 | } |
| 304 | |
| 305 | /// \brief Make these results show that the name was found in |
| 306 | /// base classes of different types. |
| 307 | /// |
| 308 | /// The given paths object is copied and invalidated. |
| 309 | void setAmbiguousBaseSubobjectTypes(CXXBasePaths &P); |
| 310 | |
| 311 | /// \brief Make these results show that the name was found in |
| 312 | /// distinct base classes of the same type. |
| 313 | /// |
| 314 | /// The given paths object is copied and invalidated. |
| 315 | void setAmbiguousBaseSubobjects(CXXBasePaths &P); |
| 316 | |
| 317 | /// \brief Make these results show that the name was found in |
| 318 | /// different contexts and a tag decl was hidden by an ordinary |
| 319 | /// decl in a different context. |
| 320 | void setAmbiguousQualifiedTagHiding() { |
| 321 | setAmbiguous(AmbiguousTagHiding); |
| 322 | } |
| 323 | |
| 324 | /// \brief Clears out any current state. |
| 325 | void clear() { |
| 326 | ResultKind = NotFound; |
| 327 | Decls.clear(); |
| 328 | if (Paths) deletePaths(Paths); |
| 329 | Paths = NULL; |
| 330 | } |
| 331 | |
| 332 | /// \brief Clears out any current state and re-initializes for a |
| 333 | /// different kind of lookup. |
| 334 | void clear(Sema::LookupNameKind Kind) { |
| 335 | clear(); |
| 336 | LookupKind = Kind; |
| 337 | } |
| 338 | |
| 339 | void print(llvm::raw_ostream &); |
| 340 | |
| 341 | /// Suppress the diagnostics that would normally fire because of this |
| 342 | /// lookup. This happens during (e.g.) redeclaration lookups. |
| 343 | void suppressDiagnostics() { |
| 344 | Diagnose = false; |
| 345 | } |
| 346 | |
| 347 | /// Sets a 'context' source range. |
| 348 | void setContextRange(SourceRange SR) { |
| 349 | NameContextRange = SR; |
| 350 | } |
| 351 | |
| 352 | /// Gets the source range of the context of this name; for C++ |
| 353 | /// qualified lookups, this is the source range of the scope |
| 354 | /// specifier. |
| 355 | SourceRange getContextRange() const { |
| 356 | return NameContextRange; |
| 357 | } |
| 358 | |
| 359 | /// Gets the location of the identifier. This isn't always defined: |
| 360 | /// sometimes we're doing lookups on synthesized names. |
| 361 | SourceLocation getNameLoc() const { |
| 362 | return NameLoc; |
| 363 | } |
| 364 | |
John McCall | 6826314 | 2009-11-18 22:49:29 +0000 | [diff] [blame^] | 365 | /// A class for iterating through a result set and possibly |
| 366 | /// filtering out results. The results returned are possibly |
| 367 | /// sugared. |
| 368 | class Filter { |
| 369 | LookupResult &Results; |
| 370 | unsigned I; |
| 371 | bool ErasedAny; |
| 372 | #ifndef NDEBUG |
| 373 | bool CalledDone; |
| 374 | #endif |
| 375 | |
| 376 | friend class LookupResult; |
| 377 | Filter(LookupResult &Results) |
| 378 | : Results(Results), I(0), ErasedAny(false) |
| 379 | #ifndef NDEBUG |
| 380 | , CalledDone(false) |
| 381 | #endif |
| 382 | {} |
| 383 | |
| 384 | public: |
| 385 | #ifndef NDEBUG |
| 386 | ~Filter() { |
| 387 | assert(CalledDone && |
| 388 | "LookupResult::Filter destroyed without done() call"); |
| 389 | } |
| 390 | #endif |
| 391 | |
| 392 | bool hasNext() const { |
| 393 | return I != Results.Decls.size(); |
| 394 | } |
| 395 | |
| 396 | NamedDecl *next() { |
| 397 | assert(I < Results.Decls.size() && "next() called on empty filter"); |
| 398 | return Results.Decls[I++]; |
| 399 | } |
| 400 | |
| 401 | /// Erase the last element returned from this iterator. |
| 402 | void erase() { |
| 403 | Results.Decls[--I] = Results.Decls.back(); |
| 404 | Results.Decls.pop_back(); |
| 405 | ErasedAny = true; |
| 406 | } |
| 407 | |
| 408 | void done() { |
| 409 | #ifndef NDEBUG |
| 410 | assert(!CalledDone && "done() called twice"); |
| 411 | CalledDone = true; |
| 412 | #endif |
| 413 | |
| 414 | if (ErasedAny) |
| 415 | Results.resolveKindAfterFilter(); |
| 416 | } |
| 417 | }; |
| 418 | |
| 419 | /// Create a filter for this result set. |
| 420 | Filter makeFilter() { |
| 421 | return Filter(*this); |
| 422 | } |
| 423 | |
John McCall | 7d384dd | 2009-11-18 07:57:50 +0000 | [diff] [blame] | 424 | private: |
| 425 | void diagnose() { |
| 426 | if (isAmbiguous()) |
| 427 | SemaRef.DiagnoseAmbiguousLookup(*this); |
| 428 | } |
| 429 | |
| 430 | void setAmbiguous(AmbiguityKind AK) { |
| 431 | ResultKind = Ambiguous; |
| 432 | Ambiguity = AK; |
| 433 | } |
| 434 | |
| 435 | void addDeclsFromBasePaths(const CXXBasePaths &P); |
| 436 | |
| 437 | // Sanity checks. |
| 438 | void sanity() const { |
| 439 | assert(ResultKind != NotFound || Decls.size() == 0); |
| 440 | assert(ResultKind != Found || Decls.size() == 1); |
| 441 | assert(ResultKind == NotFound || ResultKind == Found || |
| 442 | ResultKind == FoundUnresolvedValue || |
| 443 | (ResultKind == Ambiguous && Ambiguity == AmbiguousBaseSubobjects) |
| 444 | || Decls.size() > 1); |
| 445 | assert((Paths != NULL) == (ResultKind == Ambiguous && |
| 446 | (Ambiguity == AmbiguousBaseSubobjectTypes || |
| 447 | Ambiguity == AmbiguousBaseSubobjects))); |
| 448 | } |
| 449 | |
| 450 | static void deletePaths(CXXBasePaths *); |
| 451 | |
| 452 | // Results. |
| 453 | LookupResultKind ResultKind; |
| 454 | AmbiguityKind Ambiguity; // ill-defined unless ambiguous |
| 455 | DeclsTy Decls; |
| 456 | CXXBasePaths *Paths; |
| 457 | |
| 458 | // Parameters. |
| 459 | Sema &SemaRef; |
| 460 | DeclarationName Name; |
| 461 | SourceLocation NameLoc; |
| 462 | SourceRange NameContextRange; |
| 463 | Sema::LookupNameKind LookupKind; |
| 464 | unsigned IDNS; // ill-defined until set by lookup |
| 465 | bool Redecl; |
| 466 | |
| 467 | /// \brief True if tag declarations should be hidden if non-tags |
| 468 | /// are present |
| 469 | bool HideTags; |
| 470 | |
| 471 | bool Diagnose; |
| 472 | }; |
| 473 | |
| 474 | } |
| 475 | |
| 476 | #endif |