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 single NRVO candidate variable in this scope. 214 /// There are three possible values: 215 /// 1) pointer to VarDecl that denotes NRVO candidate itself. 216 /// 2) nullptr value means that NRVO is not allowed in this scope 217 /// (e.g. return a function parameter). 218 /// 3) None value means that there is no NRVO candidate in this scope 219 /// (i.e. there are no return statements in this scope). 220 Optional<VarDecl *> NRVO; 221 222 /// Represents return slots for NRVO candidates in the current scope. 223 /// If a variable is present in this set, it means that a return slot is 224 /// available for this variable in the current scope. 225 llvm::SmallPtrSet<VarDecl *, 8> ReturnSlots; 226 227 void setFlags(Scope *Parent, unsigned F); 228 229 public: 230 Scope(Scope *Parent, unsigned ScopeFlags, DiagnosticsEngine &Diag) 231 : ErrorTrap(Diag) { 232 Init(Parent, ScopeFlags); 233 } 234 235 /// getFlags - Return the flags for this scope. 236 unsigned getFlags() const { return Flags; } 237 238 void setFlags(unsigned F) { setFlags(getParent(), F); } 239 240 /// isBlockScope - Return true if this scope correspond to a closure. 241 bool isBlockScope() const { return Flags & BlockScope; } 242 243 /// getParent - Return the scope that this is nested in. 244 const Scope *getParent() const { return AnyParent; } 245 Scope *getParent() { return AnyParent; } 246 247 /// getFnParent - Return the closest scope that is a function body. 248 const Scope *getFnParent() const { return FnParent; } 249 Scope *getFnParent() { return FnParent; } 250 251 const Scope *getMSLastManglingParent() const { 252 return MSLastManglingParent; 253 } 254 Scope *getMSLastManglingParent() { return MSLastManglingParent; } 255 256 /// getContinueParent - Return the closest scope that a continue statement 257 /// would be affected by. 258 Scope *getContinueParent() { 259 return ContinueParent; 260 } 261 262 const Scope *getContinueParent() const { 263 return const_cast<Scope*>(this)->getContinueParent(); 264 } 265 266 // Set whether we're in the scope of a condition variable, where 'continue' 267 // is disallowed despite being a continue scope. 268 void setIsConditionVarScope(bool InConditionVarScope) { 269 Flags = (Flags & ~ConditionVarScope) | 270 (InConditionVarScope ? ConditionVarScope : 0); 271 } 272 273 bool isConditionVarScope() const { 274 return Flags & ConditionVarScope; 275 } 276 277 /// getBreakParent - Return the closest scope that a break statement 278 /// would be affected by. 279 Scope *getBreakParent() { 280 return BreakParent; 281 } 282 const Scope *getBreakParent() const { 283 return const_cast<Scope*>(this)->getBreakParent(); 284 } 285 286 Scope *getBlockParent() { return BlockParent; } 287 const Scope *getBlockParent() const { return BlockParent; } 288 289 Scope *getTemplateParamParent() { return TemplateParamParent; } 290 const Scope *getTemplateParamParent() const { return TemplateParamParent; } 291 292 /// Returns the depth of this scope. The translation-unit has scope depth 0. 293 unsigned getDepth() const { return Depth; } 294 295 /// Returns the number of function prototype scopes in this scope 296 /// chain. 297 unsigned getFunctionPrototypeDepth() const { 298 return PrototypeDepth; 299 } 300 301 /// Return the number of parameters declared in this function 302 /// prototype, increasing it by one for the next call. 303 unsigned getNextFunctionPrototypeIndex() { 304 assert(isFunctionPrototypeScope()); 305 return PrototypeIndex++; 306 } 307 308 using decl_range = llvm::iterator_range<DeclSetTy::iterator>; 309 310 decl_range decls() const { 311 return decl_range(DeclsInScope.begin(), DeclsInScope.end()); 312 } 313 314 bool decl_empty() const { return DeclsInScope.empty(); } 315 316 void AddDecl(Decl *D) { 317 if (auto *VD = dyn_cast<VarDecl>(D)) 318 if (!isa<ParmVarDecl>(VD)) 319 ReturnSlots.insert(VD); 320 321 DeclsInScope.insert(D); 322 } 323 324 void RemoveDecl(Decl *D) { 325 DeclsInScope.erase(D); 326 } 327 328 void incrementMSManglingNumber() { 329 if (Scope *MSLMP = getMSLastManglingParent()) { 330 MSLMP->MSLastManglingNumber += 1; 331 MSCurManglingNumber += 1; 332 } 333 } 334 335 void decrementMSManglingNumber() { 336 if (Scope *MSLMP = getMSLastManglingParent()) { 337 MSLMP->MSLastManglingNumber -= 1; 338 MSCurManglingNumber -= 1; 339 } 340 } 341 342 unsigned getMSLastManglingNumber() const { 343 if (const Scope *MSLMP = getMSLastManglingParent()) 344 return MSLMP->MSLastManglingNumber; 345 return 1; 346 } 347 348 unsigned getMSCurManglingNumber() const { 349 return MSCurManglingNumber; 350 } 351 352 /// isDeclScope - Return true if this is the scope that the specified decl is 353 /// declared in. 354 bool isDeclScope(const Decl *D) const { return DeclsInScope.contains(D); } 355 356 /// Get the entity corresponding to this scope. 357 DeclContext *getEntity() const { 358 return isTemplateParamScope() ? nullptr : Entity; 359 } 360 361 /// Get the DeclContext in which to continue unqualified lookup after a 362 /// lookup in this scope. 363 DeclContext *getLookupEntity() const { return Entity; } 364 365 void setEntity(DeclContext *E) { 366 assert(!isTemplateParamScope() && 367 "entity associated with template param scope"); 368 Entity = E; 369 } 370 void setLookupEntity(DeclContext *E) { Entity = E; } 371 372 /// Determine whether any unrecoverable errors have occurred within this 373 /// scope. Note that this may return false even if the scope contains invalid 374 /// declarations or statements, if the errors for those invalid constructs 375 /// were suppressed because some prior invalid construct was referenced. 376 bool hasUnrecoverableErrorOccurred() const { 377 return ErrorTrap.hasUnrecoverableErrorOccurred(); 378 } 379 380 /// isFunctionScope() - Return true if this scope is a function scope. 381 bool isFunctionScope() const { return getFlags() & Scope::FnScope; } 382 383 /// isClassScope - Return true if this scope is a class/struct/union scope. 384 bool isClassScope() const { return getFlags() & Scope::ClassScope; } 385 386 /// Determines whether this scope is between inheritance colon and the real 387 /// class/struct definition. 388 bool isClassInheritanceScope() const { 389 return getFlags() & Scope::ClassInheritanceScope; 390 } 391 392 /// isInCXXInlineMethodScope - Return true if this scope is a C++ inline 393 /// method scope or is inside one. 394 bool isInCXXInlineMethodScope() const { 395 if (const Scope *FnS = getFnParent()) { 396 assert(FnS->getParent() && "TUScope not created?"); 397 return FnS->getParent()->isClassScope(); 398 } 399 return false; 400 } 401 402 /// isInObjcMethodScope - Return true if this scope is, or is contained in, an 403 /// Objective-C method body. Note that this method is not constant time. 404 bool isInObjcMethodScope() const { 405 for (const Scope *S = this; S; S = S->getParent()) { 406 // If this scope is an objc method scope, then we succeed. 407 if (S->getFlags() & ObjCMethodScope) 408 return true; 409 } 410 return false; 411 } 412 413 /// isInObjcMethodOuterScope - Return true if this scope is an 414 /// Objective-C method outer most body. 415 bool isInObjcMethodOuterScope() const { 416 if (const Scope *S = this) { 417 // If this scope is an objc method scope, then we succeed. 418 if (S->getFlags() & ObjCMethodScope) 419 return true; 420 } 421 return false; 422 } 423 424 /// isTemplateParamScope - Return true if this scope is a C++ 425 /// template parameter scope. 426 bool isTemplateParamScope() const { 427 return getFlags() & Scope::TemplateParamScope; 428 } 429 430 /// isFunctionPrototypeScope - Return true if this scope is a 431 /// function prototype scope. 432 bool isFunctionPrototypeScope() const { 433 return getFlags() & Scope::FunctionPrototypeScope; 434 } 435 436 /// isFunctionDeclarationScope - Return true if this scope is a 437 /// function prototype scope. 438 bool isFunctionDeclarationScope() const { 439 return getFlags() & Scope::FunctionDeclarationScope; 440 } 441 442 /// isAtCatchScope - Return true if this scope is \@catch. 443 bool isAtCatchScope() const { 444 return getFlags() & Scope::AtCatchScope; 445 } 446 447 /// isCatchScope - Return true if this scope is a C++ catch statement. 448 bool isCatchScope() const { return getFlags() & Scope::CatchScope; } 449 450 /// isSwitchScope - Return true if this scope is a switch scope. 451 bool isSwitchScope() const { 452 for (const Scope *S = this; S; S = S->getParent()) { 453 if (S->getFlags() & Scope::SwitchScope) 454 return true; 455 else if (S->getFlags() & (Scope::FnScope | Scope::ClassScope | 456 Scope::BlockScope | Scope::TemplateParamScope | 457 Scope::FunctionPrototypeScope | 458 Scope::AtCatchScope | Scope::ObjCMethodScope)) 459 return false; 460 } 461 return false; 462 } 463 464 /// Determines whether this scope is the OpenMP directive scope 465 bool isOpenMPDirectiveScope() const { 466 return (getFlags() & Scope::OpenMPDirectiveScope); 467 } 468 469 /// Determine whether this scope is some OpenMP loop directive scope 470 /// (for example, 'omp for', 'omp simd'). 471 bool isOpenMPLoopDirectiveScope() const { 472 if (getFlags() & Scope::OpenMPLoopDirectiveScope) { 473 assert(isOpenMPDirectiveScope() && 474 "OpenMP loop directive scope is not a directive scope"); 475 return true; 476 } 477 return false; 478 } 479 480 /// Determine whether this scope is (or is nested into) some OpenMP 481 /// loop simd directive scope (for example, 'omp simd', 'omp for simd'). 482 bool isOpenMPSimdDirectiveScope() const { 483 return getFlags() & Scope::OpenMPSimdDirectiveScope; 484 } 485 486 /// Determine whether this scope is a loop having OpenMP loop 487 /// directive attached. 488 bool isOpenMPLoopScope() const { 489 const Scope *P = getParent(); 490 return P && P->isOpenMPLoopDirectiveScope(); 491 } 492 493 /// Determine whether this scope is a while/do/for statement, which can have 494 /// continue statements embedded into it. 495 bool isContinueScope() const { 496 return getFlags() & ScopeFlags::ContinueScope; 497 } 498 499 /// Determine whether this scope is a C++ 'try' block. 500 bool isTryScope() const { return getFlags() & Scope::TryScope; } 501 502 /// Determine whether this scope is a function-level C++ try or catch scope. 503 bool isFnTryCatchScope() const { 504 return getFlags() & ScopeFlags::FnTryCatchScope; 505 } 506 507 /// Determine whether this scope is a SEH '__try' block. 508 bool isSEHTryScope() const { return getFlags() & Scope::SEHTryScope; } 509 510 /// Determine whether this scope is a SEH '__except' block. 511 bool isSEHExceptScope() const { return getFlags() & Scope::SEHExceptScope; } 512 513 /// Determine whether this scope is a compound statement scope. 514 bool isCompoundStmtScope() const { 515 return getFlags() & Scope::CompoundStmtScope; 516 } 517 518 /// Determine whether this scope is a controlling scope in a 519 /// if/switch/while/for statement. 520 bool isControlScope() const { return getFlags() & Scope::ControlScope; } 521 522 /// Returns if rhs has a higher scope depth than this. 523 /// 524 /// The caller is responsible for calling this only if one of the two scopes 525 /// is an ancestor of the other. 526 bool Contains(const Scope& rhs) const { return Depth < rhs.Depth; } 527 528 /// containedInPrototypeScope - Return true if this or a parent scope 529 /// is a FunctionPrototypeScope. 530 bool containedInPrototypeScope() const; 531 532 void PushUsingDirective(UsingDirectiveDecl *UDir) { 533 UsingDirectives.push_back(UDir); 534 } 535 536 using using_directives_range = 537 llvm::iterator_range<UsingDirectivesTy::iterator>; 538 539 using_directives_range using_directives() { 540 return using_directives_range(UsingDirectives.begin(), 541 UsingDirectives.end()); 542 } 543 544 void updateNRVOCandidate(VarDecl *VD); 545 546 void applyNRVO(); 547 548 /// Init - This is used by the parser to implement scope caching. 549 void Init(Scope *parent, unsigned flags); 550 551 /// Sets up the specified scope flags and adjusts the scope state 552 /// variables accordingly. 553 void AddFlags(unsigned Flags); 554 555 void dumpImpl(raw_ostream &OS) const; 556 void dump() const; 557 }; 558 559 } // namespace clang 560 561 #endif // LLVM_CLANG_SEMA_SCOPE_H 562