1 //===- Scope.h - Scope interface --------------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file defines the Scope interface. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_CLANG_SEMA_SCOPE_H 14 #define LLVM_CLANG_SEMA_SCOPE_H 15 16 #include "clang/AST/Decl.h" 17 #include "clang/Basic/Diagnostic.h" 18 #include "llvm/ADT/PointerIntPair.h" 19 #include "llvm/ADT/SmallPtrSet.h" 20 #include "llvm/ADT/SmallVector.h" 21 #include "llvm/ADT/iterator_range.h" 22 #include <cassert> 23 24 namespace llvm { 25 26 class raw_ostream; 27 28 } // namespace llvm 29 30 namespace clang { 31 32 class Decl; 33 class DeclContext; 34 class UsingDirectiveDecl; 35 class VarDecl; 36 37 /// Scope - A scope is a transient data structure that is used while parsing the 38 /// program. It assists with resolving identifiers to the appropriate 39 /// declaration. 40 class Scope { 41 public: 42 /// ScopeFlags - These are bitfields that are or'd together when creating a 43 /// scope, which defines the sorts of things the scope contains. 44 enum ScopeFlags { 45 /// This indicates that the scope corresponds to a function, which 46 /// means that labels are set here. 47 FnScope = 0x01, 48 49 /// This is a while, do, switch, for, etc that can have break 50 /// statements embedded into it. 51 BreakScope = 0x02, 52 53 /// This is a while, do, for, which can have continue statements 54 /// embedded into it. 55 ContinueScope = 0x04, 56 57 /// This is a scope that can contain a declaration. Some scopes 58 /// just contain loop constructs but don't contain decls. 59 DeclScope = 0x08, 60 61 /// The controlling scope in a if/switch/while/for statement. 62 ControlScope = 0x10, 63 64 /// The scope of a struct/union/class definition. 65 ClassScope = 0x20, 66 67 /// This is a scope that corresponds to a block/closure object. 68 /// Blocks serve as top-level scopes for some objects like labels, they 69 /// also prevent things like break and continue. BlockScopes always have 70 /// the FnScope and DeclScope flags set as well. 71 BlockScope = 0x40, 72 73 /// This is a scope that corresponds to the 74 /// template parameters of a C++ template. Template parameter 75 /// scope starts at the 'template' keyword and ends when the 76 /// template declaration ends. 77 TemplateParamScope = 0x80, 78 79 /// This is a scope that corresponds to the 80 /// parameters within a function prototype. 81 FunctionPrototypeScope = 0x100, 82 83 /// This is a scope that corresponds to the parameters within 84 /// a function prototype for a function declaration (as opposed to any 85 /// other kind of function declarator). Always has FunctionPrototypeScope 86 /// set as well. 87 FunctionDeclarationScope = 0x200, 88 89 /// This is a scope that corresponds to the Objective-C 90 /// \@catch statement. 91 AtCatchScope = 0x400, 92 93 /// This scope corresponds to an Objective-C method body. 94 /// It always has FnScope and DeclScope set as well. 95 ObjCMethodScope = 0x800, 96 97 /// This is a scope that corresponds to a switch statement. 98 SwitchScope = 0x1000, 99 100 /// This is the scope of a C++ try statement. 101 TryScope = 0x2000, 102 103 /// This is the scope for a function-level C++ try or catch scope. 104 FnTryCatchScope = 0x4000, 105 106 /// This is the scope of OpenMP executable directive. 107 OpenMPDirectiveScope = 0x8000, 108 109 /// This is the scope of some OpenMP loop directive. 110 OpenMPLoopDirectiveScope = 0x10000, 111 112 /// This is the scope of some OpenMP simd directive. 113 /// For example, it is used for 'omp simd', 'omp for simd'. 114 /// This flag is propagated to children scopes. 115 OpenMPSimdDirectiveScope = 0x20000, 116 117 /// This scope corresponds to an enum. 118 EnumScope = 0x40000, 119 120 /// This scope corresponds to an SEH try. 121 SEHTryScope = 0x80000, 122 123 /// This scope corresponds to an SEH except. 124 SEHExceptScope = 0x100000, 125 126 /// We are currently in the filter expression of an SEH except block. 127 SEHFilterScope = 0x200000, 128 129 /// This is a compound statement scope. 130 CompoundStmtScope = 0x400000, 131 132 /// We are between inheritance colon and the real class/struct definition 133 /// scope. 134 ClassInheritanceScope = 0x800000, 135 136 /// This is the scope of a C++ catch statement. 137 CatchScope = 0x1000000, 138 139 /// This is a scope in which a condition variable is currently being 140 /// parsed. If such a scope is a ContinueScope, it's invalid to jump to the 141 /// continue block from here. 142 ConditionVarScope = 0x2000000, 143 }; 144 145 private: 146 /// The parent scope for this scope. This is null for the translation-unit 147 /// scope. 148 Scope *AnyParent; 149 150 /// Flags - This contains a set of ScopeFlags, which indicates how the scope 151 /// interrelates with other control flow statements. 152 unsigned Flags; 153 154 /// Depth - This is the depth of this scope. The translation-unit scope has 155 /// depth 0. 156 unsigned short Depth; 157 158 /// Declarations with static linkage are mangled with the number of 159 /// scopes seen as a component. 160 unsigned short MSLastManglingNumber; 161 162 unsigned short MSCurManglingNumber; 163 164 /// PrototypeDepth - This is the number of function prototype scopes 165 /// enclosing this scope, including this scope. 166 unsigned short PrototypeDepth; 167 168 /// PrototypeIndex - This is the number of parameters currently 169 /// declared in this scope. 170 unsigned short PrototypeIndex; 171 172 /// FnParent - If this scope has a parent scope that is a function body, this 173 /// pointer is non-null and points to it. This is used for label processing. 174 Scope *FnParent; 175 Scope *MSLastManglingParent; 176 177 /// BreakParent/ContinueParent - This is a direct link to the innermost 178 /// BreakScope/ContinueScope which contains the contents of this scope 179 /// for control flow purposes (and might be this scope itself), or null 180 /// if there is no such scope. 181 Scope *BreakParent, *ContinueParent; 182 183 /// BlockParent - This is a direct link to the immediately containing 184 /// BlockScope if this scope is not one, or null if there is none. 185 Scope *BlockParent; 186 187 /// TemplateParamParent - This is a direct link to the 188 /// immediately containing template parameter scope. In the 189 /// case of nested templates, template parameter scopes can have 190 /// other template parameter scopes as parents. 191 Scope *TemplateParamParent; 192 193 /// DeclsInScope - This keeps track of all declarations in this scope. When 194 /// the declaration is added to the scope, it is set as the current 195 /// declaration for the identifier in the IdentifierTable. When the scope is 196 /// popped, these declarations are removed from the IdentifierTable's notion 197 /// of current declaration. It is up to the current Action implementation to 198 /// implement these semantics. 199 using DeclSetTy = llvm::SmallPtrSet<Decl *, 32>; 200 DeclSetTy DeclsInScope; 201 202 /// The DeclContext with which this scope is associated. For 203 /// example, the entity of a class scope is the class itself, the 204 /// entity of a function scope is a function, etc. 205 DeclContext *Entity; 206 207 using UsingDirectivesTy = SmallVector<UsingDirectiveDecl *, 2>; 208 UsingDirectivesTy UsingDirectives; 209 210 /// Used to determine if errors occurred in this scope. 211 DiagnosticErrorTrap ErrorTrap; 212 213 /// A lattice consisting of undefined, a single NRVO candidate variable in 214 /// this scope, or over-defined. The bit is true when over-defined. 215 llvm::PointerIntPair<VarDecl *, 1, bool> NRVO; 216 217 void setFlags(Scope *Parent, unsigned F); 218 219 public: 220 Scope(Scope *Parent, unsigned ScopeFlags, DiagnosticsEngine &Diag) 221 : ErrorTrap(Diag) { 222 Init(Parent, ScopeFlags); 223 } 224 225 /// getFlags - Return the flags for this scope. 226 unsigned getFlags() const { return Flags; } 227 228 void setFlags(unsigned F) { setFlags(getParent(), F); } 229 230 /// isBlockScope - Return true if this scope correspond to a closure. 231 bool isBlockScope() const { return Flags & BlockScope; } 232 233 /// getParent - Return the scope that this is nested in. 234 const Scope *getParent() const { return AnyParent; } 235 Scope *getParent() { return AnyParent; } 236 237 /// getFnParent - Return the closest scope that is a function body. 238 const Scope *getFnParent() const { return FnParent; } 239 Scope *getFnParent() { return FnParent; } 240 241 const Scope *getMSLastManglingParent() const { 242 return MSLastManglingParent; 243 } 244 Scope *getMSLastManglingParent() { return MSLastManglingParent; } 245 246 /// getContinueParent - Return the closest scope that a continue statement 247 /// would be affected by. 248 Scope *getContinueParent() { 249 return ContinueParent; 250 } 251 252 const Scope *getContinueParent() const { 253 return const_cast<Scope*>(this)->getContinueParent(); 254 } 255 256 // Set whether we're in the scope of a condition variable, where 'continue' 257 // is disallowed despite being a continue scope. 258 void setIsConditionVarScope(bool InConditionVarScope) { 259 Flags = (Flags & ~ConditionVarScope) | 260 (InConditionVarScope ? ConditionVarScope : 0); 261 } 262 263 bool isConditionVarScope() const { 264 return Flags & ConditionVarScope; 265 } 266 267 /// getBreakParent - Return the closest scope that a break statement 268 /// would be affected by. 269 Scope *getBreakParent() { 270 return BreakParent; 271 } 272 const Scope *getBreakParent() const { 273 return const_cast<Scope*>(this)->getBreakParent(); 274 } 275 276 Scope *getBlockParent() { return BlockParent; } 277 const Scope *getBlockParent() const { return BlockParent; } 278 279 Scope *getTemplateParamParent() { return TemplateParamParent; } 280 const Scope *getTemplateParamParent() const { return TemplateParamParent; } 281 282 /// Returns the depth of this scope. The translation-unit has scope depth 0. 283 unsigned getDepth() const { return Depth; } 284 285 /// Returns the number of function prototype scopes in this scope 286 /// chain. 287 unsigned getFunctionPrototypeDepth() const { 288 return PrototypeDepth; 289 } 290 291 /// Return the number of parameters declared in this function 292 /// prototype, increasing it by one for the next call. 293 unsigned getNextFunctionPrototypeIndex() { 294 assert(isFunctionPrototypeScope()); 295 return PrototypeIndex++; 296 } 297 298 using decl_range = llvm::iterator_range<DeclSetTy::iterator>; 299 300 decl_range decls() const { 301 return decl_range(DeclsInScope.begin(), DeclsInScope.end()); 302 } 303 304 bool decl_empty() const { return DeclsInScope.empty(); } 305 306 void AddDecl(Decl *D) { 307 DeclsInScope.insert(D); 308 } 309 310 void RemoveDecl(Decl *D) { 311 DeclsInScope.erase(D); 312 } 313 314 void incrementMSManglingNumber() { 315 if (Scope *MSLMP = getMSLastManglingParent()) { 316 MSLMP->MSLastManglingNumber += 1; 317 MSCurManglingNumber += 1; 318 } 319 } 320 321 void decrementMSManglingNumber() { 322 if (Scope *MSLMP = getMSLastManglingParent()) { 323 MSLMP->MSLastManglingNumber -= 1; 324 MSCurManglingNumber -= 1; 325 } 326 } 327 328 unsigned getMSLastManglingNumber() const { 329 if (const Scope *MSLMP = getMSLastManglingParent()) 330 return MSLMP->MSLastManglingNumber; 331 return 1; 332 } 333 334 unsigned getMSCurManglingNumber() const { 335 return MSCurManglingNumber; 336 } 337 338 /// isDeclScope - Return true if this is the scope that the specified decl is 339 /// declared in. 340 bool isDeclScope(const Decl *D) const { return DeclsInScope.contains(D); } 341 342 /// Get the entity corresponding to this scope. 343 DeclContext *getEntity() const { 344 return isTemplateParamScope() ? nullptr : Entity; 345 } 346 347 /// Get the DeclContext in which to continue unqualified lookup after a 348 /// lookup in this scope. 349 DeclContext *getLookupEntity() const { return Entity; } 350 351 void setEntity(DeclContext *E) { 352 assert(!isTemplateParamScope() && 353 "entity associated with template param scope"); 354 Entity = E; 355 } 356 void setLookupEntity(DeclContext *E) { Entity = E; } 357 358 /// Determine whether any unrecoverable errors have occurred within this 359 /// scope. Note that this may return false even if the scope contains invalid 360 /// declarations or statements, if the errors for those invalid constructs 361 /// were suppressed because some prior invalid construct was referenced. 362 bool hasUnrecoverableErrorOccurred() const { 363 return ErrorTrap.hasUnrecoverableErrorOccurred(); 364 } 365 366 /// isFunctionScope() - Return true if this scope is a function scope. 367 bool isFunctionScope() const { return (getFlags() & Scope::FnScope); } 368 369 /// isClassScope - Return true if this scope is a class/struct/union scope. 370 bool isClassScope() const { 371 return (getFlags() & Scope::ClassScope); 372 } 373 374 /// isInCXXInlineMethodScope - Return true if this scope is a C++ inline 375 /// method scope or is inside one. 376 bool isInCXXInlineMethodScope() const { 377 if (const Scope *FnS = getFnParent()) { 378 assert(FnS->getParent() && "TUScope not created?"); 379 return FnS->getParent()->isClassScope(); 380 } 381 return false; 382 } 383 384 /// isInObjcMethodScope - Return true if this scope is, or is contained in, an 385 /// Objective-C method body. Note that this method is not constant time. 386 bool isInObjcMethodScope() const { 387 for (const Scope *S = this; S; S = S->getParent()) { 388 // If this scope is an objc method scope, then we succeed. 389 if (S->getFlags() & ObjCMethodScope) 390 return true; 391 } 392 return false; 393 } 394 395 /// isInObjcMethodOuterScope - Return true if this scope is an 396 /// Objective-C method outer most body. 397 bool isInObjcMethodOuterScope() const { 398 if (const Scope *S = this) { 399 // If this scope is an objc method scope, then we succeed. 400 if (S->getFlags() & ObjCMethodScope) 401 return true; 402 } 403 return false; 404 } 405 406 /// isTemplateParamScope - Return true if this scope is a C++ 407 /// template parameter scope. 408 bool isTemplateParamScope() const { 409 return getFlags() & Scope::TemplateParamScope; 410 } 411 412 /// isFunctionPrototypeScope - Return true if this scope is a 413 /// function prototype scope. 414 bool isFunctionPrototypeScope() const { 415 return getFlags() & Scope::FunctionPrototypeScope; 416 } 417 418 /// isFunctionDeclarationScope - Return true if this scope is a 419 /// function prototype scope. 420 bool isFunctionDeclarationScope() const { 421 return getFlags() & Scope::FunctionDeclarationScope; 422 } 423 424 /// isAtCatchScope - Return true if this scope is \@catch. 425 bool isAtCatchScope() const { 426 return getFlags() & Scope::AtCatchScope; 427 } 428 429 /// isSwitchScope - Return true if this scope is a switch scope. 430 bool isSwitchScope() const { 431 for (const Scope *S = this; S; S = S->getParent()) { 432 if (S->getFlags() & Scope::SwitchScope) 433 return true; 434 else if (S->getFlags() & (Scope::FnScope | Scope::ClassScope | 435 Scope::BlockScope | Scope::TemplateParamScope | 436 Scope::FunctionPrototypeScope | 437 Scope::AtCatchScope | Scope::ObjCMethodScope)) 438 return false; 439 } 440 return false; 441 } 442 443 /// Determines whether this scope is the OpenMP directive scope 444 bool isOpenMPDirectiveScope() const { 445 return (getFlags() & Scope::OpenMPDirectiveScope); 446 } 447 448 /// Determine whether this scope is some OpenMP loop directive scope 449 /// (for example, 'omp for', 'omp simd'). 450 bool isOpenMPLoopDirectiveScope() const { 451 if (getFlags() & Scope::OpenMPLoopDirectiveScope) { 452 assert(isOpenMPDirectiveScope() && 453 "OpenMP loop directive scope is not a directive scope"); 454 return true; 455 } 456 return false; 457 } 458 459 /// Determine whether this scope is (or is nested into) some OpenMP 460 /// loop simd directive scope (for example, 'omp simd', 'omp for simd'). 461 bool isOpenMPSimdDirectiveScope() const { 462 return getFlags() & Scope::OpenMPSimdDirectiveScope; 463 } 464 465 /// Determine whether this scope is a loop having OpenMP loop 466 /// directive attached. 467 bool isOpenMPLoopScope() const { 468 const Scope *P = getParent(); 469 return P && P->isOpenMPLoopDirectiveScope(); 470 } 471 472 /// Determine whether this scope is a C++ 'try' block. 473 bool isTryScope() const { return getFlags() & Scope::TryScope; } 474 475 /// Determine whether this scope is a SEH '__try' block. 476 bool isSEHTryScope() const { return getFlags() & Scope::SEHTryScope; } 477 478 /// Determine whether this scope is a SEH '__except' block. 479 bool isSEHExceptScope() const { return getFlags() & Scope::SEHExceptScope; } 480 481 /// Determine whether this scope is a compound statement scope. 482 bool isCompoundStmtScope() const { 483 return getFlags() & Scope::CompoundStmtScope; 484 } 485 486 /// Returns if rhs has a higher scope depth than this. 487 /// 488 /// The caller is responsible for calling this only if one of the two scopes 489 /// is an ancestor of the other. 490 bool Contains(const Scope& rhs) const { return Depth < rhs.Depth; } 491 492 /// containedInPrototypeScope - Return true if this or a parent scope 493 /// is a FunctionPrototypeScope. 494 bool containedInPrototypeScope() const; 495 496 void PushUsingDirective(UsingDirectiveDecl *UDir) { 497 UsingDirectives.push_back(UDir); 498 } 499 500 using using_directives_range = 501 llvm::iterator_range<UsingDirectivesTy::iterator>; 502 503 using_directives_range using_directives() { 504 return using_directives_range(UsingDirectives.begin(), 505 UsingDirectives.end()); 506 } 507 508 void addNRVOCandidate(VarDecl *VD) { 509 if (NRVO.getInt()) 510 return; 511 if (NRVO.getPointer() == nullptr) { 512 NRVO.setPointer(VD); 513 return; 514 } 515 if (NRVO.getPointer() != VD) 516 setNoNRVO(); 517 } 518 519 void setNoNRVO() { 520 NRVO.setInt(true); 521 NRVO.setPointer(nullptr); 522 } 523 524 void mergeNRVOIntoParent(); 525 526 /// Init - This is used by the parser to implement scope caching. 527 void Init(Scope *parent, unsigned flags); 528 529 /// Sets up the specified scope flags and adjusts the scope state 530 /// variables accordingly. 531 void AddFlags(unsigned Flags); 532 533 void dumpImpl(raw_ostream &OS) const; 534 void dump() const; 535 }; 536 537 } // namespace clang 538 539 #endif // LLVM_CLANG_SEMA_SCOPE_H 540