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