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