1 //===----- CGCXXABI.h - Interface to C++ ABIs -------------------*- 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 provides an abstract class for C++ code generation. Concrete subclasses 10 // of this implement code generation for specific C++ ABIs. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_CLANG_LIB_CODEGEN_CGCXXABI_H 15 #define LLVM_CLANG_LIB_CODEGEN_CGCXXABI_H 16 17 #include "CodeGenFunction.h" 18 #include "clang/Basic/LLVM.h" 19 #include "clang/CodeGen/CodeGenABITypes.h" 20 21 namespace llvm { 22 class Constant; 23 class Type; 24 class Value; 25 class CallInst; 26 } 27 28 namespace clang { 29 class CastExpr; 30 class CXXConstructorDecl; 31 class CXXDestructorDecl; 32 class CXXMethodDecl; 33 class CXXRecordDecl; 34 class MangleContext; 35 36 namespace CodeGen { 37 class CGCallee; 38 class CodeGenFunction; 39 class CodeGenModule; 40 struct CatchTypeInfo; 41 42 /// Implements C++ ABI-specific code generation functions. 43 class CGCXXABI { 44 friend class CodeGenModule; 45 46 protected: 47 CodeGenModule &CGM; 48 std::unique_ptr<MangleContext> MangleCtx; 49 50 CGCXXABI(CodeGenModule &CGM) 51 : CGM(CGM), MangleCtx(CGM.getContext().createMangleContext()) {} 52 53 protected: 54 ImplicitParamDecl *getThisDecl(CodeGenFunction &CGF) { 55 return CGF.CXXABIThisDecl; 56 } 57 llvm::Value *getThisValue(CodeGenFunction &CGF) { 58 return CGF.CXXABIThisValue; 59 } 60 Address getThisAddress(CodeGenFunction &CGF) { 61 return Address( 62 CGF.CXXABIThisValue, 63 CGF.ConvertTypeForMem(CGF.CXXABIThisDecl->getType()->getPointeeType()), 64 CGF.CXXABIThisAlignment); 65 } 66 67 /// Issue a diagnostic about unsupported features in the ABI. 68 void ErrorUnsupportedABI(CodeGenFunction &CGF, StringRef S); 69 70 /// Get a null value for unsupported member pointers. 71 llvm::Constant *GetBogusMemberPointer(QualType T); 72 73 ImplicitParamDecl *&getStructorImplicitParamDecl(CodeGenFunction &CGF) { 74 return CGF.CXXStructorImplicitParamDecl; 75 } 76 llvm::Value *&getStructorImplicitParamValue(CodeGenFunction &CGF) { 77 return CGF.CXXStructorImplicitParamValue; 78 } 79 80 /// Loads the incoming C++ this pointer as it was passed by the caller. 81 llvm::Value *loadIncomingCXXThis(CodeGenFunction &CGF); 82 83 void setCXXABIThisValue(CodeGenFunction &CGF, llvm::Value *ThisPtr); 84 85 ASTContext &getContext() const { return CGM.getContext(); } 86 87 bool mayNeedDestruction(const VarDecl *VD) const; 88 89 /// Determine whether we will definitely emit this variable with a constant 90 /// initializer, either because the language semantics demand it or because 91 /// we know that the initializer is a constant. 92 // For weak definitions, any initializer available in the current translation 93 // is not necessarily reflective of the initializer used; such initializers 94 // are ignored unless if InspectInitForWeakDef is true. 95 bool 96 isEmittedWithConstantInitializer(const VarDecl *VD, 97 bool InspectInitForWeakDef = false) const; 98 99 virtual bool requiresArrayCookie(const CXXDeleteExpr *E, QualType eltType); 100 virtual bool requiresArrayCookie(const CXXNewExpr *E); 101 102 /// Determine whether there's something special about the rules of 103 /// the ABI tell us that 'this' is a complete object within the 104 /// given function. Obvious common logic like being defined on a 105 /// final class will have been taken care of by the caller. 106 virtual bool isThisCompleteObject(GlobalDecl GD) const = 0; 107 108 public: 109 110 virtual ~CGCXXABI(); 111 112 /// Gets the mangle context. 113 MangleContext &getMangleContext() { 114 return *MangleCtx; 115 } 116 117 /// Returns true if the given constructor or destructor is one of the 118 /// kinds that the ABI says returns 'this' (only applies when called 119 /// non-virtually for destructors). 120 /// 121 /// There currently is no way to indicate if a destructor returns 'this' 122 /// when called virtually, and code generation does not support the case. 123 virtual bool HasThisReturn(GlobalDecl GD) const { return false; } 124 125 virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; } 126 127 virtual bool useSinitAndSterm() const { return false; } 128 129 /// Returns true if the target allows calling a function through a pointer 130 /// with a different signature than the actual function (or equivalently, 131 /// bitcasting a function or function pointer to a different function type). 132 /// In principle in the most general case this could depend on the target, the 133 /// calling convention, and the actual types of the arguments and return 134 /// value. Here it just means whether the signature mismatch could *ever* be 135 /// allowed; in other words, does the target do strict checking of signatures 136 /// for all calls. 137 virtual bool canCallMismatchedFunctionType() const { return true; } 138 139 /// If the C++ ABI requires the given type be returned in a particular way, 140 /// this method sets RetAI and returns true. 141 virtual bool classifyReturnType(CGFunctionInfo &FI) const = 0; 142 143 /// Specify how one should pass an argument of a record type. 144 enum RecordArgABI { 145 /// Pass it using the normal C aggregate rules for the ABI, potentially 146 /// introducing extra copies and passing some or all of it in registers. 147 RAA_Default = 0, 148 149 /// Pass it on the stack using its defined layout. The argument must be 150 /// evaluated directly into the correct stack position in the arguments area, 151 /// and the call machinery must not move it or introduce extra copies. 152 RAA_DirectInMemory, 153 154 /// Pass it as a pointer to temporary memory. 155 RAA_Indirect 156 }; 157 158 /// Returns how an argument of the given record type should be passed. 159 virtual RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const = 0; 160 161 /// Returns true if the implicit 'sret' parameter comes after the implicit 162 /// 'this' parameter of C++ instance methods. 163 virtual bool isSRetParameterAfterThis() const { return false; } 164 165 /// Returns true if the ABI permits the argument to be a homogeneous 166 /// aggregate. 167 virtual bool 168 isPermittedToBeHomogeneousAggregate(const CXXRecordDecl *RD) const { 169 return true; 170 }; 171 172 /// Find the LLVM type used to represent the given member pointer 173 /// type. 174 virtual llvm::Type * 175 ConvertMemberPointerType(const MemberPointerType *MPT); 176 177 /// Load a member function from an object and a member function 178 /// pointer. Apply the this-adjustment and set 'This' to the 179 /// adjusted value. 180 virtual CGCallee EmitLoadOfMemberFunctionPointer( 181 CodeGenFunction &CGF, const Expr *E, Address This, 182 llvm::Value *&ThisPtrForCall, llvm::Value *MemPtr, 183 const MemberPointerType *MPT); 184 185 /// Calculate an l-value from an object and a data member pointer. 186 virtual llvm::Value * 187 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E, 188 Address Base, llvm::Value *MemPtr, 189 const MemberPointerType *MPT); 190 191 /// Perform a derived-to-base, base-to-derived, or bitcast member 192 /// pointer conversion. 193 virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, 194 const CastExpr *E, 195 llvm::Value *Src); 196 197 /// Perform a derived-to-base, base-to-derived, or bitcast member 198 /// pointer conversion on a constant value. 199 virtual llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, 200 llvm::Constant *Src); 201 202 /// Return true if the given member pointer can be zero-initialized 203 /// (in the C++ sense) with an LLVM zeroinitializer. 204 virtual bool isZeroInitializable(const MemberPointerType *MPT); 205 206 /// Return whether or not a member pointers type is convertible to an IR type. 207 virtual bool isMemberPointerConvertible(const MemberPointerType *MPT) const { 208 return true; 209 } 210 211 /// Create a null member pointer of the given type. 212 virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT); 213 214 /// Create a member pointer for the given method. 215 virtual llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD); 216 217 /// Create a member pointer for the given field. 218 virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, 219 CharUnits offset); 220 221 /// Create a member pointer for the given member pointer constant. 222 virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT); 223 224 /// Emit a comparison between two member pointers. Returns an i1. 225 virtual llvm::Value * 226 EmitMemberPointerComparison(CodeGenFunction &CGF, 227 llvm::Value *L, 228 llvm::Value *R, 229 const MemberPointerType *MPT, 230 bool Inequality); 231 232 /// Determine if a member pointer is non-null. Returns an i1. 233 virtual llvm::Value * 234 EmitMemberPointerIsNotNull(CodeGenFunction &CGF, 235 llvm::Value *MemPtr, 236 const MemberPointerType *MPT); 237 238 protected: 239 /// A utility method for computing the offset required for the given 240 /// base-to-derived or derived-to-base member-pointer conversion. 241 /// Does not handle virtual conversions (in case we ever fully 242 /// support an ABI that allows this). Returns null if no adjustment 243 /// is required. 244 llvm::Constant *getMemberPointerAdjustment(const CastExpr *E); 245 246 public: 247 virtual void emitVirtualObjectDelete(CodeGenFunction &CGF, 248 const CXXDeleteExpr *DE, 249 Address Ptr, QualType ElementType, 250 const CXXDestructorDecl *Dtor) = 0; 251 virtual void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) = 0; 252 virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0; 253 virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; } 254 255 /// Determine whether it's possible to emit a vtable for \p RD, even 256 /// though we do not know that the vtable has been marked as used by semantic 257 /// analysis. 258 virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const = 0; 259 260 virtual void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) = 0; 261 262 virtual llvm::CallInst * 263 emitTerminateForUnexpectedException(CodeGenFunction &CGF, 264 llvm::Value *Exn); 265 266 virtual llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) = 0; 267 virtual CatchTypeInfo 268 getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) = 0; 269 virtual CatchTypeInfo getCatchAllTypeInfo(); 270 271 virtual bool shouldTypeidBeNullChecked(bool IsDeref, 272 QualType SrcRecordTy) = 0; 273 virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0; 274 virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy, 275 Address ThisPtr, 276 llvm::Type *StdTypeInfoPtrTy) = 0; 277 278 virtual bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, 279 QualType SrcRecordTy) = 0; 280 281 virtual llvm::Value * 282 EmitDynamicCastCall(CodeGenFunction &CGF, Address Value, 283 QualType SrcRecordTy, QualType DestTy, 284 QualType DestRecordTy, llvm::BasicBlock *CastEnd) = 0; 285 286 virtual llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, 287 Address Value, 288 QualType SrcRecordTy, 289 QualType DestTy) = 0; 290 291 virtual bool EmitBadCastCall(CodeGenFunction &CGF) = 0; 292 293 virtual llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF, 294 Address This, 295 const CXXRecordDecl *ClassDecl, 296 const CXXRecordDecl *BaseClassDecl) = 0; 297 298 virtual llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF, 299 const CXXRecordDecl *RD); 300 301 /// Emit the code to initialize hidden members required 302 /// to handle virtual inheritance, if needed by the ABI. 303 virtual void 304 initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF, 305 const CXXRecordDecl *RD) {} 306 307 /// Emit constructor variants required by this ABI. 308 virtual void EmitCXXConstructors(const CXXConstructorDecl *D) = 0; 309 310 /// Additional implicit arguments to add to the beginning (Prefix) and end 311 /// (Suffix) of a constructor / destructor arg list. 312 /// 313 /// Note that Prefix should actually be inserted *after* the first existing 314 /// arg; `this` arguments always come first. 315 struct AddedStructorArgs { 316 struct Arg { 317 llvm::Value *Value; 318 QualType Type; 319 }; 320 SmallVector<Arg, 1> Prefix; 321 SmallVector<Arg, 1> Suffix; 322 AddedStructorArgs() = default; 323 AddedStructorArgs(SmallVector<Arg, 1> P, SmallVector<Arg, 1> S) 324 : Prefix(std::move(P)), Suffix(std::move(S)) {} 325 static AddedStructorArgs prefix(SmallVector<Arg, 1> Args) { 326 return {std::move(Args), {}}; 327 } 328 static AddedStructorArgs suffix(SmallVector<Arg, 1> Args) { 329 return {{}, std::move(Args)}; 330 } 331 }; 332 333 /// Similar to AddedStructorArgs, but only notes the number of additional 334 /// arguments. 335 struct AddedStructorArgCounts { 336 unsigned Prefix = 0; 337 unsigned Suffix = 0; 338 AddedStructorArgCounts() = default; 339 AddedStructorArgCounts(unsigned P, unsigned S) : Prefix(P), Suffix(S) {} 340 static AddedStructorArgCounts prefix(unsigned N) { return {N, 0}; } 341 static AddedStructorArgCounts suffix(unsigned N) { return {0, N}; } 342 }; 343 344 /// Build the signature of the given constructor or destructor variant by 345 /// adding any required parameters. For convenience, ArgTys has been 346 /// initialized with the type of 'this'. 347 virtual AddedStructorArgCounts 348 buildStructorSignature(GlobalDecl GD, 349 SmallVectorImpl<CanQualType> &ArgTys) = 0; 350 351 /// Returns true if the given destructor type should be emitted as a linkonce 352 /// delegating thunk, regardless of whether the dtor is defined in this TU or 353 /// not. 354 virtual bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, 355 CXXDtorType DT) const = 0; 356 357 virtual void setCXXDestructorDLLStorage(llvm::GlobalValue *GV, 358 const CXXDestructorDecl *Dtor, 359 CXXDtorType DT) const; 360 361 virtual llvm::GlobalValue::LinkageTypes 362 getCXXDestructorLinkage(GVALinkage Linkage, const CXXDestructorDecl *Dtor, 363 CXXDtorType DT) const; 364 365 /// Emit destructor variants required by this ABI. 366 virtual void EmitCXXDestructors(const CXXDestructorDecl *D) = 0; 367 368 /// Get the type of the implicit "this" parameter used by a method. May return 369 /// zero if no specific type is applicable, e.g. if the ABI expects the "this" 370 /// parameter to point to some artificial offset in a complete object due to 371 /// vbases being reordered. 372 virtual const CXXRecordDecl * 373 getThisArgumentTypeForMethod(const CXXMethodDecl *MD) { 374 return MD->getParent(); 375 } 376 377 /// Perform ABI-specific "this" argument adjustment required prior to 378 /// a call of a virtual function. 379 /// The "VirtualCall" argument is true iff the call itself is virtual. 380 virtual Address 381 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD, 382 Address This, bool VirtualCall) { 383 return This; 384 } 385 386 /// Build a parameter variable suitable for 'this'. 387 void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params); 388 389 /// Insert any ABI-specific implicit parameters into the parameter list for a 390 /// function. This generally involves extra data for constructors and 391 /// destructors. 392 /// 393 /// ABIs may also choose to override the return type, which has been 394 /// initialized with the type of 'this' if HasThisReturn(CGF.CurGD) is true or 395 /// the formal return type of the function otherwise. 396 virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy, 397 FunctionArgList &Params) = 0; 398 399 /// Get the ABI-specific "this" parameter adjustment to apply in the prologue 400 /// of a virtual function. 401 virtual CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) { 402 return CharUnits::Zero(); 403 } 404 405 /// Emit the ABI-specific prolog for the function. 406 virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0; 407 408 virtual AddedStructorArgs 409 getImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D, 410 CXXCtorType Type, bool ForVirtualBase, 411 bool Delegating) = 0; 412 413 /// Add any ABI-specific implicit arguments needed to call a constructor. 414 /// 415 /// \return The number of arguments added at the beginning and end of the 416 /// call, which is typically zero or one. 417 AddedStructorArgCounts 418 addImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D, 419 CXXCtorType Type, bool ForVirtualBase, 420 bool Delegating, CallArgList &Args); 421 422 /// Get the implicit (second) parameter that comes after the "this" pointer, 423 /// or nullptr if there is isn't one. 424 virtual llvm::Value * 425 getCXXDestructorImplicitParam(CodeGenFunction &CGF, 426 const CXXDestructorDecl *DD, CXXDtorType Type, 427 bool ForVirtualBase, bool Delegating) = 0; 428 429 /// Emit the destructor call. 430 virtual void EmitDestructorCall(CodeGenFunction &CGF, 431 const CXXDestructorDecl *DD, CXXDtorType Type, 432 bool ForVirtualBase, bool Delegating, 433 Address This, QualType ThisTy) = 0; 434 435 /// Emits the VTable definitions required for the given record type. 436 virtual void emitVTableDefinitions(CodeGenVTables &CGVT, 437 const CXXRecordDecl *RD) = 0; 438 439 /// Checks if ABI requires extra virtual offset for vtable field. 440 virtual bool 441 isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF, 442 CodeGenFunction::VPtr Vptr) = 0; 443 444 /// Checks if ABI requires to initialize vptrs for given dynamic class. 445 virtual bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) = 0; 446 447 /// Get the address point of the vtable for the given base subobject. 448 virtual llvm::Constant * 449 getVTableAddressPoint(BaseSubobject Base, 450 const CXXRecordDecl *VTableClass) = 0; 451 452 /// Get the address point of the vtable for the given base subobject while 453 /// building a constructor or a destructor. 454 virtual llvm::Value * 455 getVTableAddressPointInStructor(CodeGenFunction &CGF, const CXXRecordDecl *RD, 456 BaseSubobject Base, 457 const CXXRecordDecl *NearestVBase) = 0; 458 459 /// Get the address point of the vtable for the given base subobject while 460 /// building a constexpr. 461 virtual llvm::Constant * 462 getVTableAddressPointForConstExpr(BaseSubobject Base, 463 const CXXRecordDecl *VTableClass) = 0; 464 465 /// Get the address of the vtable for the given record decl which should be 466 /// used for the vptr at the given offset in RD. 467 virtual llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, 468 CharUnits VPtrOffset) = 0; 469 470 /// Build a virtual function pointer in the ABI-specific way. 471 virtual CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF, 472 GlobalDecl GD, Address This, 473 llvm::Type *Ty, 474 SourceLocation Loc) = 0; 475 476 using DeleteOrMemberCallExpr = 477 llvm::PointerUnion<const CXXDeleteExpr *, const CXXMemberCallExpr *>; 478 479 /// Emit the ABI-specific virtual destructor call. 480 virtual llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF, 481 const CXXDestructorDecl *Dtor, 482 CXXDtorType DtorType, 483 Address This, 484 DeleteOrMemberCallExpr E) = 0; 485 486 virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, 487 GlobalDecl GD, 488 CallArgList &CallArgs) {} 489 490 /// Emit any tables needed to implement virtual inheritance. For Itanium, 491 /// this emits virtual table tables. For the MSVC++ ABI, this emits virtual 492 /// base tables. 493 virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD) = 0; 494 495 virtual bool exportThunk() = 0; 496 virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, 497 GlobalDecl GD, bool ReturnAdjustment) = 0; 498 499 virtual llvm::Value *performThisAdjustment(CodeGenFunction &CGF, 500 Address This, 501 const ThisAdjustment &TA) = 0; 502 503 virtual llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, 504 Address Ret, 505 const ReturnAdjustment &RA) = 0; 506 507 virtual void EmitReturnFromThunk(CodeGenFunction &CGF, 508 RValue RV, QualType ResultType); 509 510 virtual size_t getSrcArgforCopyCtor(const CXXConstructorDecl *, 511 FunctionArgList &Args) const = 0; 512 513 /// Gets the offsets of all the virtual base pointers in a given class. 514 virtual std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD); 515 516 /// Gets the pure virtual member call function. 517 virtual StringRef GetPureVirtualCallName() = 0; 518 519 /// Gets the deleted virtual member call name. 520 virtual StringRef GetDeletedVirtualCallName() = 0; 521 522 /**************************** Array cookies ******************************/ 523 524 /// Returns the extra size required in order to store the array 525 /// cookie for the given new-expression. May return 0 to indicate that no 526 /// array cookie is required. 527 /// 528 /// Several cases are filtered out before this method is called: 529 /// - non-array allocations never need a cookie 530 /// - calls to \::operator new(size_t, void*) never need a cookie 531 /// 532 /// \param expr - the new-expression being allocated. 533 virtual CharUnits GetArrayCookieSize(const CXXNewExpr *expr); 534 535 /// Initialize the array cookie for the given allocation. 536 /// 537 /// \param NewPtr - a char* which is the presumed-non-null 538 /// return value of the allocation function 539 /// \param NumElements - the computed number of elements, 540 /// potentially collapsed from the multidimensional array case; 541 /// always a size_t 542 /// \param ElementType - the base element allocated type, 543 /// i.e. the allocated type after stripping all array types 544 virtual Address InitializeArrayCookie(CodeGenFunction &CGF, 545 Address NewPtr, 546 llvm::Value *NumElements, 547 const CXXNewExpr *expr, 548 QualType ElementType); 549 550 /// Reads the array cookie associated with the given pointer, 551 /// if it has one. 552 /// 553 /// \param Ptr - a pointer to the first element in the array 554 /// \param ElementType - the base element type of elements of the array 555 /// \param NumElements - an out parameter which will be initialized 556 /// with the number of elements allocated, or zero if there is no 557 /// cookie 558 /// \param AllocPtr - an out parameter which will be initialized 559 /// with a char* pointing to the address returned by the allocation 560 /// function 561 /// \param CookieSize - an out parameter which will be initialized 562 /// with the size of the cookie, or zero if there is no cookie 563 virtual void ReadArrayCookie(CodeGenFunction &CGF, Address Ptr, 564 const CXXDeleteExpr *expr, 565 QualType ElementType, llvm::Value *&NumElements, 566 llvm::Value *&AllocPtr, CharUnits &CookieSize); 567 568 /// Return whether the given global decl needs a VTT parameter. 569 virtual bool NeedsVTTParameter(GlobalDecl GD); 570 571 protected: 572 /// Returns the extra size required in order to store the array 573 /// cookie for the given type. Assumes that an array cookie is 574 /// required. 575 virtual CharUnits getArrayCookieSizeImpl(QualType elementType); 576 577 /// Reads the array cookie for an allocation which is known to have one. 578 /// This is called by the standard implementation of ReadArrayCookie. 579 /// 580 /// \param ptr - a pointer to the allocation made for an array, as a char* 581 /// \param cookieSize - the computed cookie size of an array 582 /// 583 /// Other parameters are as above. 584 /// 585 /// \return a size_t 586 virtual llvm::Value *readArrayCookieImpl(CodeGenFunction &IGF, Address ptr, 587 CharUnits cookieSize); 588 589 public: 590 591 /*************************** Static local guards ****************************/ 592 593 /// Emits the guarded initializer and destructor setup for the given 594 /// variable, given that it couldn't be emitted as a constant. 595 /// If \p PerformInit is false, the initialization has been folded to a 596 /// constant and should not be performed. 597 /// 598 /// The variable may be: 599 /// - a static local variable 600 /// - a static data member of a class template instantiation 601 virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, 602 llvm::GlobalVariable *DeclPtr, 603 bool PerformInit) = 0; 604 605 /// Emit code to force the execution of a destructor during global 606 /// teardown. The default implementation of this uses atexit. 607 /// 608 /// \param Dtor - a function taking a single pointer argument 609 /// \param Addr - a pointer to pass to the destructor function. 610 virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, 611 llvm::FunctionCallee Dtor, 612 llvm::Constant *Addr) = 0; 613 614 /*************************** thread_local initialization ********************/ 615 616 /// Emits ABI-required functions necessary to initialize thread_local 617 /// variables in this translation unit. 618 /// 619 /// \param CXXThreadLocals - The thread_local declarations in this translation 620 /// unit. 621 /// \param CXXThreadLocalInits - If this translation unit contains any 622 /// non-constant initialization or non-trivial destruction for 623 /// thread_local variables, a list of functions to perform the 624 /// initialization. 625 virtual void EmitThreadLocalInitFuncs( 626 CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals, 627 ArrayRef<llvm::Function *> CXXThreadLocalInits, 628 ArrayRef<const VarDecl *> CXXThreadLocalInitVars) = 0; 629 630 // Determine if references to thread_local global variables can be made 631 // directly or require access through a thread wrapper function. 632 virtual bool usesThreadWrapperFunction(const VarDecl *VD) const = 0; 633 634 /// Emit a reference to a non-local thread_local variable (including 635 /// triggering the initialization of all thread_local variables in its 636 /// translation unit). 637 virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, 638 const VarDecl *VD, 639 QualType LValType) = 0; 640 641 /// Emit a single constructor/destructor with the given type from a C++ 642 /// constructor Decl. 643 virtual void emitCXXStructor(GlobalDecl GD) = 0; 644 645 /// Load a vtable from This, an object of polymorphic type RD, or from one of 646 /// its virtual bases if it does not have its own vtable. Returns the vtable 647 /// and the class from which the vtable was loaded. 648 virtual std::pair<llvm::Value *, const CXXRecordDecl *> 649 LoadVTablePtr(CodeGenFunction &CGF, Address This, 650 const CXXRecordDecl *RD) = 0; 651 }; 652 653 // Create an instance of a C++ ABI class: 654 655 /// Creates an Itanium-family ABI. 656 CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM); 657 658 /// Creates a Microsoft-family ABI. 659 CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM); 660 661 struct CatchRetScope final : EHScopeStack::Cleanup { 662 llvm::CatchPadInst *CPI; 663 664 CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {} 665 666 void Emit(CodeGenFunction &CGF, Flags flags) override { 667 llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest"); 668 CGF.Builder.CreateCatchRet(CPI, BB); 669 CGF.EmitBlock(BB); 670 } 671 }; 672 } 673 } 674 675 #endif 676