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 scope. 133 ClassInheritanceScope = 0x800000, 134 135 /// This is the scope of a C++ catch statement. 136 CatchScope = 0x1000000, 137 }; 138 139 private: 140 /// The parent scope for this scope. This is null for the translation-unit 141 /// scope. 142 Scope *AnyParent; 143 144 /// Flags - This contains a set of ScopeFlags, which indicates how the scope 145 /// interrelates with other control flow statements. 146 unsigned Flags; 147 148 /// Depth - This is the depth of this scope. The translation-unit scope has 149 /// depth 0. 150 unsigned short Depth; 151 152 /// Declarations with static linkage are mangled with the number of 153 /// scopes seen as a component. 154 unsigned short MSLastManglingNumber; 155 156 unsigned short MSCurManglingNumber; 157 158 /// PrototypeDepth - This is the number of function prototype scopes 159 /// enclosing this scope, including this scope. 160 unsigned short PrototypeDepth; 161 162 /// PrototypeIndex - This is the number of parameters currently 163 /// declared in this scope. 164 unsigned short PrototypeIndex; 165 166 /// FnParent - If this scope has a parent scope that is a function body, this 167 /// pointer is non-null and points to it. This is used for label processing. 168 Scope *FnParent; 169 Scope *MSLastManglingParent; 170 171 /// BreakParent/ContinueParent - This is a direct link to the innermost 172 /// BreakScope/ContinueScope which contains the contents of this scope 173 /// for control flow purposes (and might be this scope itself), or null 174 /// if there is no such scope. 175 Scope *BreakParent, *ContinueParent; 176 177 /// BlockParent - This is a direct link to the immediately containing 178 /// BlockScope if this scope is not one, or null if there is none. 179 Scope *BlockParent; 180 181 /// TemplateParamParent - This is a direct link to the 182 /// immediately containing template parameter scope. In the 183 /// case of nested templates, template parameter scopes can have 184 /// other template parameter scopes as parents. 185 Scope *TemplateParamParent; 186 187 /// DeclsInScope - This keeps track of all declarations in this scope. When 188 /// the declaration is added to the scope, it is set as the current 189 /// declaration for the identifier in the IdentifierTable. When the scope is 190 /// popped, these declarations are removed from the IdentifierTable's notion 191 /// of current declaration. It is up to the current Action implementation to 192 /// implement these semantics. 193 using DeclSetTy = llvm::SmallPtrSet<Decl *, 32>; 194 DeclSetTy DeclsInScope; 195 196 /// The DeclContext with which this scope is associated. For 197 /// example, the entity of a class scope is the class itself, the 198 /// entity of a function scope is a function, etc. 199 DeclContext *Entity; 200 201 using UsingDirectivesTy = SmallVector<UsingDirectiveDecl *, 2>; 202 UsingDirectivesTy UsingDirectives; 203 204 /// Used to determine if errors occurred in this scope. 205 DiagnosticErrorTrap ErrorTrap; 206 207 /// A lattice consisting of undefined, a single NRVO candidate variable in 208 /// this scope, or over-defined. The bit is true when over-defined. 209 llvm::PointerIntPair<VarDecl *, 1, bool> NRVO; 210 211 void setFlags(Scope *Parent, unsigned F); 212 213 public: 214 Scope(Scope *Parent, unsigned ScopeFlags, DiagnosticsEngine &Diag) 215 : ErrorTrap(Diag) { 216 Init(Parent, ScopeFlags); 217 } 218 219 /// getFlags - Return the flags for this scope. 220 unsigned getFlags() const { return Flags; } 221 222 void setFlags(unsigned F) { setFlags(getParent(), F); } 223 224 /// isBlockScope - Return true if this scope correspond to a closure. 225 bool isBlockScope() const { return Flags & BlockScope; } 226 227 /// getParent - Return the scope that this is nested in. 228 const Scope *getParent() const { return AnyParent; } 229 Scope *getParent() { return AnyParent; } 230 231 /// getFnParent - Return the closest scope that is a function body. 232 const Scope *getFnParent() const { return FnParent; } 233 Scope *getFnParent() { return FnParent; } 234 235 const Scope *getMSLastManglingParent() const { 236 return MSLastManglingParent; 237 } 238 Scope *getMSLastManglingParent() { return MSLastManglingParent; } 239 240 /// getContinueParent - Return the closest scope that a continue statement 241 /// would be affected by. 242 Scope *getContinueParent() { 243 return ContinueParent; 244 } 245 246 const Scope *getContinueParent() const { 247 return const_cast<Scope*>(this)->getContinueParent(); 248 } 249 250 /// getBreakParent - Return the closest scope that a break statement 251 /// would be affected by. 252 Scope *getBreakParent() { 253 return BreakParent; 254 } 255 const Scope *getBreakParent() const { 256 return const_cast<Scope*>(this)->getBreakParent(); 257 } 258 259 Scope *getBlockParent() { return BlockParent; } 260 const Scope *getBlockParent() const { return BlockParent; } 261 262 Scope *getTemplateParamParent() { return TemplateParamParent; } 263 const Scope *getTemplateParamParent() const { return TemplateParamParent; } 264 265 /// Returns the depth of this scope. The translation-unit has scope depth 0. 266 unsigned getDepth() const { return Depth; } 267 268 /// Returns the number of function prototype scopes in this scope 269 /// chain. 270 unsigned getFunctionPrototypeDepth() const { 271 return PrototypeDepth; 272 } 273 274 /// Return the number of parameters declared in this function 275 /// prototype, increasing it by one for the next call. 276 unsigned getNextFunctionPrototypeIndex() { 277 assert(isFunctionPrototypeScope()); 278 return PrototypeIndex++; 279 } 280 281 using decl_range = llvm::iterator_range<DeclSetTy::iterator>; 282 283 decl_range decls() const { 284 return decl_range(DeclsInScope.begin(), DeclsInScope.end()); 285 } 286 287 bool decl_empty() const { return DeclsInScope.empty(); } 288 289 void AddDecl(Decl *D) { 290 DeclsInScope.insert(D); 291 } 292 293 void RemoveDecl(Decl *D) { 294 DeclsInScope.erase(D); 295 } 296 297 void incrementMSManglingNumber() { 298 if (Scope *MSLMP = getMSLastManglingParent()) { 299 MSLMP->MSLastManglingNumber += 1; 300 MSCurManglingNumber += 1; 301 } 302 } 303 304 void decrementMSManglingNumber() { 305 if (Scope *MSLMP = getMSLastManglingParent()) { 306 MSLMP->MSLastManglingNumber -= 1; 307 MSCurManglingNumber -= 1; 308 } 309 } 310 311 unsigned getMSLastManglingNumber() const { 312 if (const Scope *MSLMP = getMSLastManglingParent()) 313 return MSLMP->MSLastManglingNumber; 314 return 1; 315 } 316 317 unsigned getMSCurManglingNumber() const { 318 return MSCurManglingNumber; 319 } 320 321 /// isDeclScope - Return true if this is the scope that the specified decl is 322 /// declared in. 323 bool isDeclScope(Decl *D) { 324 return DeclsInScope.count(D) != 0; 325 } 326 327 DeclContext *getEntity() const { return Entity; } 328 void setEntity(DeclContext *E) { Entity = E; } 329 330 bool hasErrorOccurred() const { return ErrorTrap.hasErrorOccurred(); } 331 332 bool hasUnrecoverableErrorOccurred() const { 333 return ErrorTrap.hasUnrecoverableErrorOccurred(); 334 } 335 336 /// isFunctionScope() - Return true if this scope is a function scope. 337 bool isFunctionScope() const { return (getFlags() & Scope::FnScope); } 338 339 /// isClassScope - Return true if this scope is a class/struct/union scope. 340 bool isClassScope() const { 341 return (getFlags() & Scope::ClassScope); 342 } 343 344 /// isInCXXInlineMethodScope - Return true if this scope is a C++ inline 345 /// method scope or is inside one. 346 bool isInCXXInlineMethodScope() const { 347 if (const Scope *FnS = getFnParent()) { 348 assert(FnS->getParent() && "TUScope not created?"); 349 return FnS->getParent()->isClassScope(); 350 } 351 return false; 352 } 353 354 /// isInObjcMethodScope - Return true if this scope is, or is contained in, an 355 /// Objective-C method body. Note that this method is not constant time. 356 bool isInObjcMethodScope() const { 357 for (const Scope *S = this; S; S = S->getParent()) { 358 // If this scope is an objc method scope, then we succeed. 359 if (S->getFlags() & ObjCMethodScope) 360 return true; 361 } 362 return false; 363 } 364 365 /// isInObjcMethodOuterScope - Return true if this scope is an 366 /// Objective-C method outer most body. 367 bool isInObjcMethodOuterScope() const { 368 if (const Scope *S = this) { 369 // If this scope is an objc method scope, then we succeed. 370 if (S->getFlags() & ObjCMethodScope) 371 return true; 372 } 373 return false; 374 } 375 376 /// isTemplateParamScope - Return true if this scope is a C++ 377 /// template parameter scope. 378 bool isTemplateParamScope() const { 379 return getFlags() & Scope::TemplateParamScope; 380 } 381 382 /// isFunctionPrototypeScope - Return true if this scope is a 383 /// function prototype scope. 384 bool isFunctionPrototypeScope() const { 385 return getFlags() & Scope::FunctionPrototypeScope; 386 } 387 388 /// isFunctionDeclarationScope - Return true if this scope is a 389 /// function prototype scope. 390 bool isFunctionDeclarationScope() const { 391 return getFlags() & Scope::FunctionDeclarationScope; 392 } 393 394 /// isAtCatchScope - Return true if this scope is \@catch. 395 bool isAtCatchScope() const { 396 return getFlags() & Scope::AtCatchScope; 397 } 398 399 /// isSwitchScope - Return true if this scope is a switch scope. 400 bool isSwitchScope() const { 401 for (const Scope *S = this; S; S = S->getParent()) { 402 if (S->getFlags() & Scope::SwitchScope) 403 return true; 404 else if (S->getFlags() & (Scope::FnScope | Scope::ClassScope | 405 Scope::BlockScope | Scope::TemplateParamScope | 406 Scope::FunctionPrototypeScope | 407 Scope::AtCatchScope | Scope::ObjCMethodScope)) 408 return false; 409 } 410 return false; 411 } 412 413 /// Determines whether this scope is the OpenMP directive scope 414 bool isOpenMPDirectiveScope() const { 415 return (getFlags() & Scope::OpenMPDirectiveScope); 416 } 417 418 /// Determine whether this scope is some OpenMP loop directive scope 419 /// (for example, 'omp for', 'omp simd'). 420 bool isOpenMPLoopDirectiveScope() const { 421 if (getFlags() & Scope::OpenMPLoopDirectiveScope) { 422 assert(isOpenMPDirectiveScope() && 423 "OpenMP loop directive scope is not a directive scope"); 424 return true; 425 } 426 return false; 427 } 428 429 /// Determine whether this scope is (or is nested into) some OpenMP 430 /// loop simd directive scope (for example, 'omp simd', 'omp for simd'). 431 bool isOpenMPSimdDirectiveScope() const { 432 return getFlags() & Scope::OpenMPSimdDirectiveScope; 433 } 434 435 /// Determine whether this scope is a loop having OpenMP loop 436 /// directive attached. 437 bool isOpenMPLoopScope() const { 438 const Scope *P = getParent(); 439 return P && P->isOpenMPLoopDirectiveScope(); 440 } 441 442 /// Determine whether this scope is a C++ 'try' block. 443 bool isTryScope() const { return getFlags() & Scope::TryScope; } 444 445 /// Determine whether this scope is a SEH '__try' block. 446 bool isSEHTryScope() const { return getFlags() & Scope::SEHTryScope; } 447 448 /// Determine whether this scope is a SEH '__except' block. 449 bool isSEHExceptScope() const { return getFlags() & Scope::SEHExceptScope; } 450 451 /// Determine whether this scope is a compound statement scope. 452 bool isCompoundStmtScope() const { 453 return getFlags() & Scope::CompoundStmtScope; 454 } 455 456 /// Returns if rhs has a higher scope depth than this. 457 /// 458 /// The caller is responsible for calling this only if one of the two scopes 459 /// is an ancestor of the other. 460 bool Contains(const Scope& rhs) const { return Depth < rhs.Depth; } 461 462 /// containedInPrototypeScope - Return true if this or a parent scope 463 /// is a FunctionPrototypeScope. 464 bool containedInPrototypeScope() const; 465 466 void PushUsingDirective(UsingDirectiveDecl *UDir) { 467 UsingDirectives.push_back(UDir); 468 } 469 470 using using_directives_range = 471 llvm::iterator_range<UsingDirectivesTy::iterator>; 472 473 using_directives_range using_directives() { 474 return using_directives_range(UsingDirectives.begin(), 475 UsingDirectives.end()); 476 } 477 478 void addNRVOCandidate(VarDecl *VD) { 479 if (NRVO.getInt()) 480 return; 481 if (NRVO.getPointer() == nullptr) { 482 NRVO.setPointer(VD); 483 return; 484 } 485 if (NRVO.getPointer() != VD) 486 setNoNRVO(); 487 } 488 489 void setNoNRVO() { 490 NRVO.setInt(true); 491 NRVO.setPointer(nullptr); 492 } 493 494 void mergeNRVOIntoParent(); 495 496 /// Init - This is used by the parser to implement scope caching. 497 void Init(Scope *parent, unsigned flags); 498 499 /// Sets up the specified scope flags and adjusts the scope state 500 /// variables accordingly. 501 void AddFlags(unsigned Flags); 502 503 void dumpImpl(raw_ostream &OS) const; 504 void dump() const; 505 }; 506 507 } // namespace clang 508 509 #endif // LLVM_CLANG_SEMA_SCOPE_H 510