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