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 61 Address getThisAddress(CodeGenFunction &CGF); 62 63 /// Issue a diagnostic about unsupported features in the ABI. 64 void ErrorUnsupportedABI(CodeGenFunction &CGF, StringRef S); 65 66 /// Get a null value for unsupported member pointers. 67 llvm::Constant *GetBogusMemberPointer(QualType T); 68 69 ImplicitParamDecl *&getStructorImplicitParamDecl(CodeGenFunction &CGF) { 70 return CGF.CXXStructorImplicitParamDecl; 71 } 72 llvm::Value *&getStructorImplicitParamValue(CodeGenFunction &CGF) { 73 return CGF.CXXStructorImplicitParamValue; 74 } 75 76 /// Loads the incoming C++ this pointer as it was passed by the caller. 77 llvm::Value *loadIncomingCXXThis(CodeGenFunction &CGF); 78 79 void setCXXABIThisValue(CodeGenFunction &CGF, llvm::Value *ThisPtr); 80 81 ASTContext &getContext() const { return CGM.getContext(); } 82 83 bool mayNeedDestruction(const VarDecl *VD) const; 84 85 /// Determine whether we will definitely emit this variable with a constant 86 /// initializer, either because the language semantics demand it or because 87 /// we know that the initializer is a constant. 88 // For weak definitions, any initializer available in the current translation 89 // is not necessarily reflective of the initializer used; such initializers 90 // are ignored unless if InspectInitForWeakDef is true. 91 bool 92 isEmittedWithConstantInitializer(const VarDecl *VD, 93 bool InspectInitForWeakDef = false) const; 94 95 virtual bool requiresArrayCookie(const CXXDeleteExpr *E, QualType eltType); 96 virtual bool requiresArrayCookie(const CXXNewExpr *E); 97 98 /// Determine whether there's something special about the rules of 99 /// the ABI tell us that 'this' is a complete object within the 100 /// given function. Obvious common logic like being defined on a 101 /// final class will have been taken care of by the caller. 102 virtual bool isThisCompleteObject(GlobalDecl GD) const = 0; 103 104 virtual bool constructorsAndDestructorsReturnThis() const { 105 return CGM.getCodeGenOpts().CtorDtorReturnThis; 106 } 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 { 124 if (isa<CXXConstructorDecl>(GD.getDecl()) || 125 (isa<CXXDestructorDecl>(GD.getDecl()) && 126 GD.getDtorType() != Dtor_Deleting)) 127 return constructorsAndDestructorsReturnThis(); 128 return false; 129 } 130 131 virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; } 132 133 virtual bool useSinitAndSterm() const { return false; } 134 135 /// Returns true if the target allows calling a function through a pointer 136 /// with a different signature than the actual function (or equivalently, 137 /// bitcasting a function or function pointer to a different function type). 138 /// In principle in the most general case this could depend on the target, the 139 /// calling convention, and the actual types of the arguments and return 140 /// value. Here it just means whether the signature mismatch could *ever* be 141 /// allowed; in other words, does the target do strict checking of signatures 142 /// for all calls. 143 virtual bool canCallMismatchedFunctionType() const { return true; } 144 145 /// If the C++ ABI requires the given type be returned in a particular way, 146 /// this method sets RetAI and returns true. 147 virtual bool classifyReturnType(CGFunctionInfo &FI) const = 0; 148 149 /// Specify how one should pass an argument of a record type. 150 enum RecordArgABI { 151 /// Pass it using the normal C aggregate rules for the ABI, potentially 152 /// introducing extra copies and passing some or all of it in registers. 153 RAA_Default = 0, 154 155 /// Pass it on the stack using its defined layout. The argument must be 156 /// evaluated directly into the correct stack position in the arguments area, 157 /// and the call machinery must not move it or introduce extra copies. 158 RAA_DirectInMemory, 159 160 /// Pass it as a pointer to temporary memory. 161 RAA_Indirect 162 }; 163 164 /// Returns how an argument of the given record type should be passed. 165 virtual RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const = 0; 166 167 /// Returns true if the implicit 'sret' parameter comes after the implicit 168 /// 'this' parameter of C++ instance methods. 169 virtual bool isSRetParameterAfterThis() const { return false; } 170 171 /// Returns true if the ABI permits the argument to be a homogeneous 172 /// aggregate. 173 virtual bool 174 isPermittedToBeHomogeneousAggregate(const CXXRecordDecl *RD) const { 175 return true; 176 }; 177 178 /// Find the LLVM type used to represent the given member pointer 179 /// type. 180 virtual llvm::Type * 181 ConvertMemberPointerType(const MemberPointerType *MPT); 182 183 /// Load a member function from an object and a member function 184 /// pointer. Apply the this-adjustment and set 'This' to the 185 /// adjusted value. 186 virtual CGCallee EmitLoadOfMemberFunctionPointer( 187 CodeGenFunction &CGF, const Expr *E, Address This, 188 llvm::Value *&ThisPtrForCall, llvm::Value *MemPtr, 189 const MemberPointerType *MPT); 190 191 /// Calculate an l-value from an object and a data member pointer. 192 virtual llvm::Value * 193 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E, 194 Address Base, llvm::Value *MemPtr, 195 const MemberPointerType *MPT); 196 197 /// Perform a derived-to-base, base-to-derived, or bitcast member 198 /// pointer conversion. 199 virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, 200 const CastExpr *E, 201 llvm::Value *Src); 202 203 /// Perform a derived-to-base, base-to-derived, or bitcast member 204 /// pointer conversion on a constant value. 205 virtual llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, 206 llvm::Constant *Src); 207 208 /// Return true if the given member pointer can be zero-initialized 209 /// (in the C++ sense) with an LLVM zeroinitializer. 210 virtual bool isZeroInitializable(const MemberPointerType *MPT); 211 212 /// Return whether or not a member pointers type is convertible to an IR type. 213 virtual bool isMemberPointerConvertible(const MemberPointerType *MPT) const { 214 return true; 215 } 216 217 /// Create a null member pointer of the given type. 218 virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT); 219 220 /// Create a member pointer for the given method. 221 virtual llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD); 222 223 /// Create a member pointer for the given field. 224 virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, 225 CharUnits offset); 226 227 /// Create a member pointer for the given member pointer constant. 228 virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT); 229 230 /// Emit a comparison between two member pointers. Returns an i1. 231 virtual llvm::Value * 232 EmitMemberPointerComparison(CodeGenFunction &CGF, 233 llvm::Value *L, 234 llvm::Value *R, 235 const MemberPointerType *MPT, 236 bool Inequality); 237 238 /// Determine if a member pointer is non-null. Returns an i1. 239 virtual llvm::Value * 240 EmitMemberPointerIsNotNull(CodeGenFunction &CGF, 241 llvm::Value *MemPtr, 242 const MemberPointerType *MPT); 243 244 protected: 245 /// A utility method for computing the offset required for the given 246 /// base-to-derived or derived-to-base member-pointer conversion. 247 /// Does not handle virtual conversions (in case we ever fully 248 /// support an ABI that allows this). Returns null if no adjustment 249 /// is required. 250 llvm::Constant *getMemberPointerAdjustment(const CastExpr *E); 251 252 public: 253 virtual void emitVirtualObjectDelete(CodeGenFunction &CGF, 254 const CXXDeleteExpr *DE, 255 Address Ptr, QualType ElementType, 256 const CXXDestructorDecl *Dtor) = 0; 257 virtual void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) = 0; 258 virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0; 259 virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; } 260 261 /// Determine whether it's possible to emit a vtable for \p RD, even 262 /// though we do not know that the vtable has been marked as used by semantic 263 /// analysis. 264 virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const = 0; 265 266 virtual void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) = 0; 267 268 virtual llvm::CallInst * 269 emitTerminateForUnexpectedException(CodeGenFunction &CGF, 270 llvm::Value *Exn); 271 272 virtual llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) = 0; 273 virtual CatchTypeInfo 274 getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) = 0; 275 virtual CatchTypeInfo getCatchAllTypeInfo(); 276 277 virtual bool shouldTypeidBeNullChecked(QualType SrcRecordTy) = 0; 278 virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0; 279 virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy, 280 Address ThisPtr, 281 llvm::Type *StdTypeInfoPtrTy) = 0; 282 283 virtual bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, 284 QualType SrcRecordTy) = 0; 285 virtual bool shouldEmitExactDynamicCast(QualType DestRecordTy) = 0; 286 287 virtual llvm::Value *emitDynamicCastCall(CodeGenFunction &CGF, Address Value, 288 QualType SrcRecordTy, 289 QualType DestTy, 290 QualType DestRecordTy, 291 llvm::BasicBlock *CastEnd) = 0; 292 293 virtual llvm::Value *emitDynamicCastToVoid(CodeGenFunction &CGF, 294 Address Value, 295 QualType SrcRecordTy) = 0; 296 297 /// Emit a dynamic_cast from SrcRecordTy to DestRecordTy. The cast fails if 298 /// the dynamic type of Value is not exactly DestRecordTy. 299 virtual llvm::Value *emitExactDynamicCast(CodeGenFunction &CGF, Address Value, 300 QualType SrcRecordTy, 301 QualType DestTy, 302 QualType DestRecordTy, 303 llvm::BasicBlock *CastSuccess, 304 llvm::BasicBlock *CastFail) = 0; 305 306 virtual bool EmitBadCastCall(CodeGenFunction &CGF) = 0; 307 308 virtual llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF, 309 Address This, 310 const CXXRecordDecl *ClassDecl, 311 const CXXRecordDecl *BaseClassDecl) = 0; 312 313 virtual llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF, 314 const CXXRecordDecl *RD); 315 316 /// Emit the code to initialize hidden members required 317 /// to handle virtual inheritance, if needed by the ABI. 318 virtual void 319 initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF, 320 const CXXRecordDecl *RD) {} 321 322 /// Emit constructor variants required by this ABI. 323 virtual void EmitCXXConstructors(const CXXConstructorDecl *D) = 0; 324 325 /// Additional implicit arguments to add to the beginning (Prefix) and end 326 /// (Suffix) of a constructor / destructor arg list. 327 /// 328 /// Note that Prefix should actually be inserted *after* the first existing 329 /// arg; `this` arguments always come first. 330 struct AddedStructorArgs { 331 struct Arg { 332 llvm::Value *Value; 333 QualType Type; 334 }; 335 SmallVector<Arg, 1> Prefix; 336 SmallVector<Arg, 1> Suffix; 337 AddedStructorArgs() = default; 338 AddedStructorArgs(SmallVector<Arg, 1> P, SmallVector<Arg, 1> S) 339 : Prefix(std::move(P)), Suffix(std::move(S)) {} 340 static AddedStructorArgs prefix(SmallVector<Arg, 1> Args) { 341 return {std::move(Args), {}}; 342 } 343 static AddedStructorArgs suffix(SmallVector<Arg, 1> Args) { 344 return {{}, std::move(Args)}; 345 } 346 }; 347 348 /// Similar to AddedStructorArgs, but only notes the number of additional 349 /// arguments. 350 struct AddedStructorArgCounts { 351 unsigned Prefix = 0; 352 unsigned Suffix = 0; 353 AddedStructorArgCounts() = default; 354 AddedStructorArgCounts(unsigned P, unsigned S) : Prefix(P), Suffix(S) {} 355 static AddedStructorArgCounts prefix(unsigned N) { return {N, 0}; } 356 static AddedStructorArgCounts suffix(unsigned N) { return {0, N}; } 357 }; 358 359 /// Build the signature of the given constructor or destructor variant by 360 /// adding any required parameters. For convenience, ArgTys has been 361 /// initialized with the type of 'this'. 362 virtual AddedStructorArgCounts 363 buildStructorSignature(GlobalDecl GD, 364 SmallVectorImpl<CanQualType> &ArgTys) = 0; 365 366 /// Returns true if the given destructor type should be emitted as a linkonce 367 /// delegating thunk, regardless of whether the dtor is defined in this TU or 368 /// not. 369 virtual bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, 370 CXXDtorType DT) const = 0; 371 372 virtual void setCXXDestructorDLLStorage(llvm::GlobalValue *GV, 373 const CXXDestructorDecl *Dtor, 374 CXXDtorType DT) const; 375 376 virtual llvm::GlobalValue::LinkageTypes 377 getCXXDestructorLinkage(GVALinkage Linkage, const CXXDestructorDecl *Dtor, 378 CXXDtorType DT) const; 379 380 /// Emit destructor variants required by this ABI. 381 virtual void EmitCXXDestructors(const CXXDestructorDecl *D) = 0; 382 383 /// Get the type of the implicit "this" parameter used by a method. May return 384 /// zero if no specific type is applicable, e.g. if the ABI expects the "this" 385 /// parameter to point to some artificial offset in a complete object due to 386 /// vbases being reordered. 387 virtual const CXXRecordDecl *getThisArgumentTypeForMethod(GlobalDecl GD) { 388 return cast<CXXMethodDecl>(GD.getDecl())->getParent(); 389 } 390 391 /// Perform ABI-specific "this" argument adjustment required prior to 392 /// a call of a virtual function. 393 /// The "VirtualCall" argument is true iff the call itself is virtual. 394 virtual Address 395 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD, 396 Address This, bool VirtualCall) { 397 return This; 398 } 399 400 /// Build a parameter variable suitable for 'this'. 401 void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params); 402 403 /// Insert any ABI-specific implicit parameters into the parameter list for a 404 /// function. This generally involves extra data for constructors and 405 /// destructors. 406 /// 407 /// ABIs may also choose to override the return type, which has been 408 /// initialized with the type of 'this' if HasThisReturn(CGF.CurGD) is true or 409 /// the formal return type of the function otherwise. 410 virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy, 411 FunctionArgList &Params) = 0; 412 413 /// Get the ABI-specific "this" parameter adjustment to apply in the prologue 414 /// of a virtual function. 415 virtual CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) { 416 return CharUnits::Zero(); 417 } 418 419 /// Emit the ABI-specific prolog for the function. 420 virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0; 421 422 virtual AddedStructorArgs 423 getImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D, 424 CXXCtorType Type, bool ForVirtualBase, 425 bool Delegating) = 0; 426 427 /// Add any ABI-specific implicit arguments needed to call a constructor. 428 /// 429 /// \return The number of arguments added at the beginning and end of the 430 /// call, which is typically zero or one. 431 AddedStructorArgCounts 432 addImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D, 433 CXXCtorType Type, bool ForVirtualBase, 434 bool Delegating, CallArgList &Args); 435 436 /// Get the implicit (second) parameter that comes after the "this" pointer, 437 /// or nullptr if there is isn't one. 438 virtual llvm::Value * 439 getCXXDestructorImplicitParam(CodeGenFunction &CGF, 440 const CXXDestructorDecl *DD, CXXDtorType Type, 441 bool ForVirtualBase, bool Delegating) = 0; 442 443 /// Emit the destructor call. 444 virtual void EmitDestructorCall(CodeGenFunction &CGF, 445 const CXXDestructorDecl *DD, CXXDtorType Type, 446 bool ForVirtualBase, bool Delegating, 447 Address This, QualType ThisTy) = 0; 448 449 /// Emits the VTable definitions required for the given record type. 450 virtual void emitVTableDefinitions(CodeGenVTables &CGVT, 451 const CXXRecordDecl *RD) = 0; 452 453 /// Checks if ABI requires extra virtual offset for vtable field. 454 virtual bool 455 isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF, 456 CodeGenFunction::VPtr Vptr) = 0; 457 458 /// Checks if ABI requires to initialize vptrs for given dynamic class. 459 virtual bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) = 0; 460 461 /// Get the address point of the vtable for the given base subobject. 462 virtual llvm::Constant * 463 getVTableAddressPoint(BaseSubobject Base, 464 const CXXRecordDecl *VTableClass) = 0; 465 466 /// Get the address point of the vtable for the given base subobject while 467 /// building a constructor or a destructor. 468 virtual llvm::Value * 469 getVTableAddressPointInStructor(CodeGenFunction &CGF, const CXXRecordDecl *RD, 470 BaseSubobject Base, 471 const CXXRecordDecl *NearestVBase) = 0; 472 473 /// Get the address of the vtable for the given record decl which should be 474 /// used for the vptr at the given offset in RD. 475 virtual llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, 476 CharUnits VPtrOffset) = 0; 477 478 /// Build a virtual function pointer in the ABI-specific way. 479 virtual CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF, 480 GlobalDecl GD, Address This, 481 llvm::Type *Ty, 482 SourceLocation Loc) = 0; 483 484 using DeleteOrMemberCallExpr = 485 llvm::PointerUnion<const CXXDeleteExpr *, const CXXMemberCallExpr *>; 486 487 /// Emit the ABI-specific virtual destructor call. 488 virtual llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF, 489 const CXXDestructorDecl *Dtor, 490 CXXDtorType DtorType, 491 Address This, 492 DeleteOrMemberCallExpr E) = 0; 493 494 virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, 495 GlobalDecl GD, 496 CallArgList &CallArgs) {} 497 498 /// Emit any tables needed to implement virtual inheritance. For Itanium, 499 /// this emits virtual table tables. For the MSVC++ ABI, this emits virtual 500 /// base tables. 501 virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD) = 0; 502 503 virtual bool exportThunk() = 0; 504 virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, 505 GlobalDecl GD, bool ReturnAdjustment) = 0; 506 507 virtual llvm::Value * 508 performThisAdjustment(CodeGenFunction &CGF, Address This, 509 const CXXRecordDecl *UnadjustedClass, 510 const ThunkInfo &TI) = 0; 511 512 virtual llvm::Value * 513 performReturnAdjustment(CodeGenFunction &CGF, Address Ret, 514 const CXXRecordDecl *UnadjustedClass, 515 const ReturnAdjustment &RA) = 0; 516 517 virtual void EmitReturnFromThunk(CodeGenFunction &CGF, 518 RValue RV, QualType ResultType); 519 520 virtual size_t getSrcArgforCopyCtor(const CXXConstructorDecl *, 521 FunctionArgList &Args) const = 0; 522 523 /// Gets the offsets of all the virtual base pointers in a given class. 524 virtual std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD); 525 526 /// Gets the pure virtual member call function. 527 virtual StringRef GetPureVirtualCallName() = 0; 528 529 /// Gets the deleted virtual member call name. 530 virtual StringRef GetDeletedVirtualCallName() = 0; 531 532 /**************************** Array cookies ******************************/ 533 534 /// Returns the extra size required in order to store the array 535 /// cookie for the given new-expression. May return 0 to indicate that no 536 /// array cookie is required. 537 /// 538 /// Several cases are filtered out before this method is called: 539 /// - non-array allocations never need a cookie 540 /// - calls to \::operator new(size_t, void*) never need a cookie 541 /// 542 /// \param expr - the new-expression being allocated. 543 virtual CharUnits GetArrayCookieSize(const CXXNewExpr *expr); 544 545 /// Initialize the array cookie for the given allocation. 546 /// 547 /// \param NewPtr - a char* which is the presumed-non-null 548 /// return value of the allocation function 549 /// \param NumElements - the computed number of elements, 550 /// potentially collapsed from the multidimensional array case; 551 /// always a size_t 552 /// \param ElementType - the base element allocated type, 553 /// i.e. the allocated type after stripping all array types 554 virtual Address InitializeArrayCookie(CodeGenFunction &CGF, 555 Address NewPtr, 556 llvm::Value *NumElements, 557 const CXXNewExpr *expr, 558 QualType ElementType); 559 560 /// Reads the array cookie associated with the given pointer, 561 /// if it has one. 562 /// 563 /// \param Ptr - a pointer to the first element in the array 564 /// \param ElementType - the base element type of elements of the array 565 /// \param NumElements - an out parameter which will be initialized 566 /// with the number of elements allocated, or zero if there is no 567 /// cookie 568 /// \param AllocPtr - an out parameter which will be initialized 569 /// with a char* pointing to the address returned by the allocation 570 /// function 571 /// \param CookieSize - an out parameter which will be initialized 572 /// with the size of the cookie, or zero if there is no cookie 573 virtual void ReadArrayCookie(CodeGenFunction &CGF, Address Ptr, 574 const CXXDeleteExpr *expr, 575 QualType ElementType, llvm::Value *&NumElements, 576 llvm::Value *&AllocPtr, CharUnits &CookieSize); 577 578 /// Return whether the given global decl needs a VTT parameter. 579 virtual bool NeedsVTTParameter(GlobalDecl GD); 580 581 protected: 582 /// Returns the extra size required in order to store the array 583 /// cookie for the given type. Assumes that an array cookie is 584 /// required. 585 virtual CharUnits getArrayCookieSizeImpl(QualType elementType); 586 587 /// Reads the array cookie for an allocation which is known to have one. 588 /// This is called by the standard implementation of ReadArrayCookie. 589 /// 590 /// \param ptr - a pointer to the allocation made for an array, as a char* 591 /// \param cookieSize - the computed cookie size of an array 592 /// 593 /// Other parameters are as above. 594 /// 595 /// \return a size_t 596 virtual llvm::Value *readArrayCookieImpl(CodeGenFunction &IGF, Address ptr, 597 CharUnits cookieSize); 598 599 public: 600 601 /*************************** Static local guards ****************************/ 602 603 /// Emits the guarded initializer and destructor setup for the given 604 /// variable, given that it couldn't be emitted as a constant. 605 /// If \p PerformInit is false, the initialization has been folded to a 606 /// constant and should not be performed. 607 /// 608 /// The variable may be: 609 /// - a static local variable 610 /// - a static data member of a class template instantiation 611 virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, 612 llvm::GlobalVariable *DeclPtr, 613 bool PerformInit) = 0; 614 615 /// Emit code to force the execution of a destructor during global 616 /// teardown. The default implementation of this uses atexit. 617 /// 618 /// \param Dtor - a function taking a single pointer argument 619 /// \param Addr - a pointer to pass to the destructor function. 620 virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, 621 llvm::FunctionCallee Dtor, 622 llvm::Constant *Addr) = 0; 623 624 /*************************** thread_local initialization ********************/ 625 626 /// Emits ABI-required functions necessary to initialize thread_local 627 /// variables in this translation unit. 628 /// 629 /// \param CXXThreadLocals - The thread_local declarations in this translation 630 /// unit. 631 /// \param CXXThreadLocalInits - If this translation unit contains any 632 /// non-constant initialization or non-trivial destruction for 633 /// thread_local variables, a list of functions to perform the 634 /// initialization. 635 virtual void EmitThreadLocalInitFuncs( 636 CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals, 637 ArrayRef<llvm::Function *> CXXThreadLocalInits, 638 ArrayRef<const VarDecl *> CXXThreadLocalInitVars) = 0; 639 640 // Determine if references to thread_local global variables can be made 641 // directly or require access through a thread wrapper function. 642 virtual bool usesThreadWrapperFunction(const VarDecl *VD) const = 0; 643 644 /// Emit a reference to a non-local thread_local variable (including 645 /// triggering the initialization of all thread_local variables in its 646 /// translation unit). 647 virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, 648 const VarDecl *VD, 649 QualType LValType) = 0; 650 651 /// Emit a single constructor/destructor with the given type from a C++ 652 /// constructor Decl. 653 virtual void emitCXXStructor(GlobalDecl GD) = 0; 654 655 /// Load a vtable from This, an object of polymorphic type RD, or from one of 656 /// its virtual bases if it does not have its own vtable. Returns the vtable 657 /// and the class from which the vtable was loaded. 658 virtual std::pair<llvm::Value *, const CXXRecordDecl *> 659 LoadVTablePtr(CodeGenFunction &CGF, Address This, 660 const CXXRecordDecl *RD) = 0; 661 }; 662 663 // Create an instance of a C++ ABI class: 664 665 /// Creates an Itanium-family ABI. 666 CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM); 667 668 /// Creates a Microsoft-family ABI. 669 CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM); 670 671 struct CatchRetScope final : EHScopeStack::Cleanup { 672 llvm::CatchPadInst *CPI; 673 674 CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {} 675 676 void Emit(CodeGenFunction &CGF, Flags flags) override { 677 llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest"); 678 CGF.Builder.CreateCatchRet(CPI, BB); 679 CGF.EmitBlock(BB); 680 } 681 }; 682 } 683 } 684 685 #endif 686