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 virtual bool constructorsAndDestructorsReturnThis() const { 109 return CGM.getCodeGenOpts().CtorDtorReturnThis; 110 } 111 112 public: 113 114 virtual ~CGCXXABI(); 115 116 /// Gets the mangle context. 117 MangleContext &getMangleContext() { 118 return *MangleCtx; 119 } 120 121 /// Returns true if the given constructor or destructor is one of the 122 /// kinds that the ABI says returns 'this' (only applies when called 123 /// non-virtually for destructors). 124 /// 125 /// There currently is no way to indicate if a destructor returns 'this' 126 /// when called virtually, and code generation does not support the case. 127 virtual bool HasThisReturn(GlobalDecl GD) const { 128 if (isa<CXXConstructorDecl>(GD.getDecl()) || 129 (isa<CXXDestructorDecl>(GD.getDecl()) && 130 GD.getDtorType() != Dtor_Deleting)) 131 return constructorsAndDestructorsReturnThis(); 132 return false; 133 } 134 135 virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; } 136 137 virtual bool useSinitAndSterm() const { return false; } 138 139 /// Returns true if the target allows calling a function through a pointer 140 /// with a different signature than the actual function (or equivalently, 141 /// bitcasting a function or function pointer to a different function type). 142 /// In principle in the most general case this could depend on the target, the 143 /// calling convention, and the actual types of the arguments and return 144 /// value. Here it just means whether the signature mismatch could *ever* be 145 /// allowed; in other words, does the target do strict checking of signatures 146 /// for all calls. 147 virtual bool canCallMismatchedFunctionType() const { return true; } 148 149 /// If the C++ ABI requires the given type be returned in a particular way, 150 /// this method sets RetAI and returns true. 151 virtual bool classifyReturnType(CGFunctionInfo &FI) const = 0; 152 153 /// Specify how one should pass an argument of a record type. 154 enum RecordArgABI { 155 /// Pass it using the normal C aggregate rules for the ABI, potentially 156 /// introducing extra copies and passing some or all of it in registers. 157 RAA_Default = 0, 158 159 /// Pass it on the stack using its defined layout. The argument must be 160 /// evaluated directly into the correct stack position in the arguments area, 161 /// and the call machinery must not move it or introduce extra copies. 162 RAA_DirectInMemory, 163 164 /// Pass it as a pointer to temporary memory. 165 RAA_Indirect 166 }; 167 168 /// Returns how an argument of the given record type should be passed. 169 virtual RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const = 0; 170 171 /// Returns true if the implicit 'sret' parameter comes after the implicit 172 /// 'this' parameter of C++ instance methods. 173 virtual bool isSRetParameterAfterThis() const { return false; } 174 175 /// Returns true if the ABI permits the argument to be a homogeneous 176 /// aggregate. 177 virtual bool 178 isPermittedToBeHomogeneousAggregate(const CXXRecordDecl *RD) const { 179 return true; 180 }; 181 182 /// Find the LLVM type used to represent the given member pointer 183 /// type. 184 virtual llvm::Type * 185 ConvertMemberPointerType(const MemberPointerType *MPT); 186 187 /// Load a member function from an object and a member function 188 /// pointer. Apply the this-adjustment and set 'This' to the 189 /// adjusted value. 190 virtual CGCallee EmitLoadOfMemberFunctionPointer( 191 CodeGenFunction &CGF, const Expr *E, Address This, 192 llvm::Value *&ThisPtrForCall, llvm::Value *MemPtr, 193 const MemberPointerType *MPT); 194 195 /// Calculate an l-value from an object and a data member pointer. 196 virtual llvm::Value * 197 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E, 198 Address Base, llvm::Value *MemPtr, 199 const MemberPointerType *MPT); 200 201 /// Perform a derived-to-base, base-to-derived, or bitcast member 202 /// pointer conversion. 203 virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, 204 const CastExpr *E, 205 llvm::Value *Src); 206 207 /// Perform a derived-to-base, base-to-derived, or bitcast member 208 /// pointer conversion on a constant value. 209 virtual llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, 210 llvm::Constant *Src); 211 212 /// Return true if the given member pointer can be zero-initialized 213 /// (in the C++ sense) with an LLVM zeroinitializer. 214 virtual bool isZeroInitializable(const MemberPointerType *MPT); 215 216 /// Return whether or not a member pointers type is convertible to an IR type. 217 virtual bool isMemberPointerConvertible(const MemberPointerType *MPT) const { 218 return true; 219 } 220 221 /// Create a null member pointer of the given type. 222 virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT); 223 224 /// Create a member pointer for the given method. 225 virtual llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD); 226 227 /// Create a member pointer for the given field. 228 virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, 229 CharUnits offset); 230 231 /// Create a member pointer for the given member pointer constant. 232 virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT); 233 234 /// Emit a comparison between two member pointers. Returns an i1. 235 virtual llvm::Value * 236 EmitMemberPointerComparison(CodeGenFunction &CGF, 237 llvm::Value *L, 238 llvm::Value *R, 239 const MemberPointerType *MPT, 240 bool Inequality); 241 242 /// Determine if a member pointer is non-null. Returns an i1. 243 virtual llvm::Value * 244 EmitMemberPointerIsNotNull(CodeGenFunction &CGF, 245 llvm::Value *MemPtr, 246 const MemberPointerType *MPT); 247 248 protected: 249 /// A utility method for computing the offset required for the given 250 /// base-to-derived or derived-to-base member-pointer conversion. 251 /// Does not handle virtual conversions (in case we ever fully 252 /// support an ABI that allows this). Returns null if no adjustment 253 /// is required. 254 llvm::Constant *getMemberPointerAdjustment(const CastExpr *E); 255 256 public: 257 virtual void emitVirtualObjectDelete(CodeGenFunction &CGF, 258 const CXXDeleteExpr *DE, 259 Address Ptr, QualType ElementType, 260 const CXXDestructorDecl *Dtor) = 0; 261 virtual void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) = 0; 262 virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0; 263 virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; } 264 265 /// Determine whether it's possible to emit a vtable for \p RD, even 266 /// though we do not know that the vtable has been marked as used by semantic 267 /// analysis. 268 virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const = 0; 269 270 virtual void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) = 0; 271 272 virtual llvm::CallInst * 273 emitTerminateForUnexpectedException(CodeGenFunction &CGF, 274 llvm::Value *Exn); 275 276 virtual llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) = 0; 277 virtual CatchTypeInfo 278 getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) = 0; 279 virtual CatchTypeInfo getCatchAllTypeInfo(); 280 281 virtual bool shouldTypeidBeNullChecked(bool IsDeref, 282 QualType SrcRecordTy) = 0; 283 virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0; 284 virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy, 285 Address ThisPtr, 286 llvm::Type *StdTypeInfoPtrTy) = 0; 287 288 virtual bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, 289 QualType SrcRecordTy) = 0; 290 virtual bool shouldEmitExactDynamicCast(QualType DestRecordTy) = 0; 291 292 virtual llvm::Value *emitDynamicCastCall(CodeGenFunction &CGF, Address Value, 293 QualType SrcRecordTy, 294 QualType DestTy, 295 QualType DestRecordTy, 296 llvm::BasicBlock *CastEnd) = 0; 297 298 virtual llvm::Value *emitDynamicCastToVoid(CodeGenFunction &CGF, 299 Address Value, 300 QualType SrcRecordTy) = 0; 301 302 /// Emit a dynamic_cast from SrcRecordTy to DestRecordTy. The cast fails if 303 /// the dynamic type of Value is not exactly DestRecordTy. 304 virtual llvm::Value *emitExactDynamicCast(CodeGenFunction &CGF, Address Value, 305 QualType SrcRecordTy, 306 QualType DestTy, 307 QualType DestRecordTy, 308 llvm::BasicBlock *CastSuccess, 309 llvm::BasicBlock *CastFail) = 0; 310 311 virtual bool EmitBadCastCall(CodeGenFunction &CGF) = 0; 312 313 virtual llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF, 314 Address This, 315 const CXXRecordDecl *ClassDecl, 316 const CXXRecordDecl *BaseClassDecl) = 0; 317 318 virtual llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF, 319 const CXXRecordDecl *RD); 320 321 /// Emit the code to initialize hidden members required 322 /// to handle virtual inheritance, if needed by the ABI. 323 virtual void 324 initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF, 325 const CXXRecordDecl *RD) {} 326 327 /// Emit constructor variants required by this ABI. 328 virtual void EmitCXXConstructors(const CXXConstructorDecl *D) = 0; 329 330 /// Additional implicit arguments to add to the beginning (Prefix) and end 331 /// (Suffix) of a constructor / destructor arg list. 332 /// 333 /// Note that Prefix should actually be inserted *after* the first existing 334 /// arg; `this` arguments always come first. 335 struct AddedStructorArgs { 336 struct Arg { 337 llvm::Value *Value; 338 QualType Type; 339 }; 340 SmallVector<Arg, 1> Prefix; 341 SmallVector<Arg, 1> Suffix; 342 AddedStructorArgs() = default; 343 AddedStructorArgs(SmallVector<Arg, 1> P, SmallVector<Arg, 1> S) 344 : Prefix(std::move(P)), Suffix(std::move(S)) {} 345 static AddedStructorArgs prefix(SmallVector<Arg, 1> Args) { 346 return {std::move(Args), {}}; 347 } 348 static AddedStructorArgs suffix(SmallVector<Arg, 1> Args) { 349 return {{}, std::move(Args)}; 350 } 351 }; 352 353 /// Similar to AddedStructorArgs, but only notes the number of additional 354 /// arguments. 355 struct AddedStructorArgCounts { 356 unsigned Prefix = 0; 357 unsigned Suffix = 0; 358 AddedStructorArgCounts() = default; 359 AddedStructorArgCounts(unsigned P, unsigned S) : Prefix(P), Suffix(S) {} 360 static AddedStructorArgCounts prefix(unsigned N) { return {N, 0}; } 361 static AddedStructorArgCounts suffix(unsigned N) { return {0, N}; } 362 }; 363 364 /// Build the signature of the given constructor or destructor variant by 365 /// adding any required parameters. For convenience, ArgTys has been 366 /// initialized with the type of 'this'. 367 virtual AddedStructorArgCounts 368 buildStructorSignature(GlobalDecl GD, 369 SmallVectorImpl<CanQualType> &ArgTys) = 0; 370 371 /// Returns true if the given destructor type should be emitted as a linkonce 372 /// delegating thunk, regardless of whether the dtor is defined in this TU or 373 /// not. 374 virtual bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, 375 CXXDtorType DT) const = 0; 376 377 virtual void setCXXDestructorDLLStorage(llvm::GlobalValue *GV, 378 const CXXDestructorDecl *Dtor, 379 CXXDtorType DT) const; 380 381 virtual llvm::GlobalValue::LinkageTypes 382 getCXXDestructorLinkage(GVALinkage Linkage, const CXXDestructorDecl *Dtor, 383 CXXDtorType DT) const; 384 385 /// Emit destructor variants required by this ABI. 386 virtual void EmitCXXDestructors(const CXXDestructorDecl *D) = 0; 387 388 /// Get the type of the implicit "this" parameter used by a method. May return 389 /// zero if no specific type is applicable, e.g. if the ABI expects the "this" 390 /// parameter to point to some artificial offset in a complete object due to 391 /// vbases being reordered. 392 virtual const CXXRecordDecl *getThisArgumentTypeForMethod(GlobalDecl GD) { 393 return cast<CXXMethodDecl>(GD.getDecl())->getParent(); 394 } 395 396 /// Perform ABI-specific "this" argument adjustment required prior to 397 /// a call of a virtual function. 398 /// The "VirtualCall" argument is true iff the call itself is virtual. 399 virtual Address 400 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD, 401 Address This, bool VirtualCall) { 402 return This; 403 } 404 405 /// Build a parameter variable suitable for 'this'. 406 void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params); 407 408 /// Insert any ABI-specific implicit parameters into the parameter list for a 409 /// function. This generally involves extra data for constructors and 410 /// destructors. 411 /// 412 /// ABIs may also choose to override the return type, which has been 413 /// initialized with the type of 'this' if HasThisReturn(CGF.CurGD) is true or 414 /// the formal return type of the function otherwise. 415 virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy, 416 FunctionArgList &Params) = 0; 417 418 /// Get the ABI-specific "this" parameter adjustment to apply in the prologue 419 /// of a virtual function. 420 virtual CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) { 421 return CharUnits::Zero(); 422 } 423 424 /// Emit the ABI-specific prolog for the function. 425 virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0; 426 427 virtual AddedStructorArgs 428 getImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D, 429 CXXCtorType Type, bool ForVirtualBase, 430 bool Delegating) = 0; 431 432 /// Add any ABI-specific implicit arguments needed to call a constructor. 433 /// 434 /// \return The number of arguments added at the beginning and end of the 435 /// call, which is typically zero or one. 436 AddedStructorArgCounts 437 addImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D, 438 CXXCtorType Type, bool ForVirtualBase, 439 bool Delegating, CallArgList &Args); 440 441 /// Get the implicit (second) parameter that comes after the "this" pointer, 442 /// or nullptr if there is isn't one. 443 virtual llvm::Value * 444 getCXXDestructorImplicitParam(CodeGenFunction &CGF, 445 const CXXDestructorDecl *DD, CXXDtorType Type, 446 bool ForVirtualBase, bool Delegating) = 0; 447 448 /// Emit the destructor call. 449 virtual void EmitDestructorCall(CodeGenFunction &CGF, 450 const CXXDestructorDecl *DD, CXXDtorType Type, 451 bool ForVirtualBase, bool Delegating, 452 Address This, QualType ThisTy) = 0; 453 454 /// Emits the VTable definitions required for the given record type. 455 virtual void emitVTableDefinitions(CodeGenVTables &CGVT, 456 const CXXRecordDecl *RD) = 0; 457 458 /// Checks if ABI requires extra virtual offset for vtable field. 459 virtual bool 460 isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF, 461 CodeGenFunction::VPtr Vptr) = 0; 462 463 /// Checks if ABI requires to initialize vptrs for given dynamic class. 464 virtual bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) = 0; 465 466 /// Get the address point of the vtable for the given base subobject. 467 virtual llvm::Constant * 468 getVTableAddressPoint(BaseSubobject Base, 469 const CXXRecordDecl *VTableClass) = 0; 470 471 /// Get the address point of the vtable for the given base subobject while 472 /// building a constructor or a destructor. 473 virtual llvm::Value * 474 getVTableAddressPointInStructor(CodeGenFunction &CGF, const CXXRecordDecl *RD, 475 BaseSubobject Base, 476 const CXXRecordDecl *NearestVBase) = 0; 477 478 /// Get the address point of the vtable for the given base subobject while 479 /// building a constexpr. 480 virtual llvm::Constant * 481 getVTableAddressPointForConstExpr(BaseSubobject Base, 482 const CXXRecordDecl *VTableClass) = 0; 483 484 /// Get the address of the vtable for the given record decl which should be 485 /// used for the vptr at the given offset in RD. 486 virtual llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, 487 CharUnits VPtrOffset) = 0; 488 489 /// Build a virtual function pointer in the ABI-specific way. 490 virtual CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF, 491 GlobalDecl GD, Address This, 492 llvm::Type *Ty, 493 SourceLocation Loc) = 0; 494 495 using DeleteOrMemberCallExpr = 496 llvm::PointerUnion<const CXXDeleteExpr *, const CXXMemberCallExpr *>; 497 498 /// Emit the ABI-specific virtual destructor call. 499 virtual llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF, 500 const CXXDestructorDecl *Dtor, 501 CXXDtorType DtorType, 502 Address This, 503 DeleteOrMemberCallExpr E) = 0; 504 505 virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, 506 GlobalDecl GD, 507 CallArgList &CallArgs) {} 508 509 /// Emit any tables needed to implement virtual inheritance. For Itanium, 510 /// this emits virtual table tables. For the MSVC++ ABI, this emits virtual 511 /// base tables. 512 virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD) = 0; 513 514 virtual bool exportThunk() = 0; 515 virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, 516 GlobalDecl GD, bool ReturnAdjustment) = 0; 517 518 virtual llvm::Value *performThisAdjustment(CodeGenFunction &CGF, 519 Address This, 520 const ThisAdjustment &TA) = 0; 521 522 virtual llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, 523 Address Ret, 524 const ReturnAdjustment &RA) = 0; 525 526 virtual void EmitReturnFromThunk(CodeGenFunction &CGF, 527 RValue RV, QualType ResultType); 528 529 virtual size_t getSrcArgforCopyCtor(const CXXConstructorDecl *, 530 FunctionArgList &Args) const = 0; 531 532 /// Gets the offsets of all the virtual base pointers in a given class. 533 virtual std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD); 534 535 /// Gets the pure virtual member call function. 536 virtual StringRef GetPureVirtualCallName() = 0; 537 538 /// Gets the deleted virtual member call name. 539 virtual StringRef GetDeletedVirtualCallName() = 0; 540 541 /**************************** Array cookies ******************************/ 542 543 /// Returns the extra size required in order to store the array 544 /// cookie for the given new-expression. May return 0 to indicate that no 545 /// array cookie is required. 546 /// 547 /// Several cases are filtered out before this method is called: 548 /// - non-array allocations never need a cookie 549 /// - calls to \::operator new(size_t, void*) never need a cookie 550 /// 551 /// \param expr - the new-expression being allocated. 552 virtual CharUnits GetArrayCookieSize(const CXXNewExpr *expr); 553 554 /// Initialize the array cookie for the given allocation. 555 /// 556 /// \param NewPtr - a char* which is the presumed-non-null 557 /// return value of the allocation function 558 /// \param NumElements - the computed number of elements, 559 /// potentially collapsed from the multidimensional array case; 560 /// always a size_t 561 /// \param ElementType - the base element allocated type, 562 /// i.e. the allocated type after stripping all array types 563 virtual Address InitializeArrayCookie(CodeGenFunction &CGF, 564 Address NewPtr, 565 llvm::Value *NumElements, 566 const CXXNewExpr *expr, 567 QualType ElementType); 568 569 /// Reads the array cookie associated with the given pointer, 570 /// if it has one. 571 /// 572 /// \param Ptr - a pointer to the first element in the array 573 /// \param ElementType - the base element type of elements of the array 574 /// \param NumElements - an out parameter which will be initialized 575 /// with the number of elements allocated, or zero if there is no 576 /// cookie 577 /// \param AllocPtr - an out parameter which will be initialized 578 /// with a char* pointing to the address returned by the allocation 579 /// function 580 /// \param CookieSize - an out parameter which will be initialized 581 /// with the size of the cookie, or zero if there is no cookie 582 virtual void ReadArrayCookie(CodeGenFunction &CGF, Address Ptr, 583 const CXXDeleteExpr *expr, 584 QualType ElementType, llvm::Value *&NumElements, 585 llvm::Value *&AllocPtr, CharUnits &CookieSize); 586 587 /// Return whether the given global decl needs a VTT parameter. 588 virtual bool NeedsVTTParameter(GlobalDecl GD); 589 590 protected: 591 /// Returns the extra size required in order to store the array 592 /// cookie for the given type. Assumes that an array cookie is 593 /// required. 594 virtual CharUnits getArrayCookieSizeImpl(QualType elementType); 595 596 /// Reads the array cookie for an allocation which is known to have one. 597 /// This is called by the standard implementation of ReadArrayCookie. 598 /// 599 /// \param ptr - a pointer to the allocation made for an array, as a char* 600 /// \param cookieSize - the computed cookie size of an array 601 /// 602 /// Other parameters are as above. 603 /// 604 /// \return a size_t 605 virtual llvm::Value *readArrayCookieImpl(CodeGenFunction &IGF, Address ptr, 606 CharUnits cookieSize); 607 608 public: 609 610 /*************************** Static local guards ****************************/ 611 612 /// Emits the guarded initializer and destructor setup for the given 613 /// variable, given that it couldn't be emitted as a constant. 614 /// If \p PerformInit is false, the initialization has been folded to a 615 /// constant and should not be performed. 616 /// 617 /// The variable may be: 618 /// - a static local variable 619 /// - a static data member of a class template instantiation 620 virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, 621 llvm::GlobalVariable *DeclPtr, 622 bool PerformInit) = 0; 623 624 /// Emit code to force the execution of a destructor during global 625 /// teardown. The default implementation of this uses atexit. 626 /// 627 /// \param Dtor - a function taking a single pointer argument 628 /// \param Addr - a pointer to pass to the destructor function. 629 virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, 630 llvm::FunctionCallee Dtor, 631 llvm::Constant *Addr) = 0; 632 633 /*************************** thread_local initialization ********************/ 634 635 /// Emits ABI-required functions necessary to initialize thread_local 636 /// variables in this translation unit. 637 /// 638 /// \param CXXThreadLocals - The thread_local declarations in this translation 639 /// unit. 640 /// \param CXXThreadLocalInits - If this translation unit contains any 641 /// non-constant initialization or non-trivial destruction for 642 /// thread_local variables, a list of functions to perform the 643 /// initialization. 644 virtual void EmitThreadLocalInitFuncs( 645 CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals, 646 ArrayRef<llvm::Function *> CXXThreadLocalInits, 647 ArrayRef<const VarDecl *> CXXThreadLocalInitVars) = 0; 648 649 // Determine if references to thread_local global variables can be made 650 // directly or require access through a thread wrapper function. 651 virtual bool usesThreadWrapperFunction(const VarDecl *VD) const = 0; 652 653 /// Emit a reference to a non-local thread_local variable (including 654 /// triggering the initialization of all thread_local variables in its 655 /// translation unit). 656 virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, 657 const VarDecl *VD, 658 QualType LValType) = 0; 659 660 /// Emit a single constructor/destructor with the given type from a C++ 661 /// constructor Decl. 662 virtual void emitCXXStructor(GlobalDecl GD) = 0; 663 664 /// Load a vtable from This, an object of polymorphic type RD, or from one of 665 /// its virtual bases if it does not have its own vtable. Returns the vtable 666 /// and the class from which the vtable was loaded. 667 virtual std::pair<llvm::Value *, const CXXRecordDecl *> 668 LoadVTablePtr(CodeGenFunction &CGF, Address This, 669 const CXXRecordDecl *RD) = 0; 670 }; 671 672 // Create an instance of a C++ ABI class: 673 674 /// Creates an Itanium-family ABI. 675 CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM); 676 677 /// Creates a Microsoft-family ABI. 678 CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM); 679 680 struct CatchRetScope final : EHScopeStack::Cleanup { 681 llvm::CatchPadInst *CPI; 682 683 CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {} 684 685 void Emit(CodeGenFunction &CGF, Flags flags) override { 686 llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest"); 687 CGF.Builder.CreateCatchRet(CPI, BB); 688 CGF.EmitBlock(BB); 689 } 690 }; 691 } 692 } 693 694 #endif 695