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
21namespace llvm {
22class Constant;
23class Type;
24class Value;
25class CallInst;
26}
27
28namespace clang {
29class CastExpr;
30class CXXConstructorDecl;
31class CXXDestructorDecl;
32class CXXMethodDecl;
33class CXXRecordDecl;
34class MangleContext;
35
36namespace CodeGen {
37class CGCallee;
38class CodeGenFunction;
39class CodeGenModule;
40struct CatchTypeInfo;
41
42/// Implements C++ ABI-specific code generation functions.
43class CGCXXABI {
44 friend class CodeGenModule;
45
46protected:
47 CodeGenModule &CGM;
48 std::unique_ptr<MangleContext> MangleCtx;
49
50 CGCXXABI(CodeGenModule &CGM)
51 : CGM(CGM), MangleCtx(CGM.getContext().createMangleContext()) {}
52
53protected:
54 ImplicitParamDecl *getThisDecl(CodeGenFunction &CGF) {
55 return CGF.CXXABIThisDecl;
56 }
57 llvm::Value *getThisValue(CodeGenFunction &CGF) {
58 return CGF.CXXABIThisValue;
59 }
60
61 Address getThisAddress(CodeGenFunction &CGF);
62
63 /// Issue a diagnostic about unsupported features in the ABI.
64 void ErrorUnsupportedABI(CodeGenFunction &CGF, StringRef S);
65
66 /// Get a null value for unsupported member pointers.
67 llvm::Constant *GetBogusMemberPointer(QualType T);
68
69 ImplicitParamDecl *&getStructorImplicitParamDecl(CodeGenFunction &CGF) {
70 return CGF.CXXStructorImplicitParamDecl;
71 }
72 llvm::Value *&getStructorImplicitParamValue(CodeGenFunction &CGF) {
73 return CGF.CXXStructorImplicitParamValue;
74 }
75
76 /// Loads the incoming C++ this pointer as it was passed by the caller.
77 llvm::Value *loadIncomingCXXThis(CodeGenFunction &CGF);
78
79 void setCXXABIThisValue(CodeGenFunction &CGF, llvm::Value *ThisPtr);
80
81 ASTContext &getContext() const { return CGM.getContext(); }
82
83 bool mayNeedDestruction(const VarDecl *VD) const;
84
85 /// Determine whether we will definitely emit this variable with a constant
86 /// initializer, either because the language semantics demand it or because
87 /// we know that the initializer is a constant.
88 // For weak definitions, any initializer available in the current translation
89 // is not necessarily reflective of the initializer used; such initializers
90 // are ignored unless if InspectInitForWeakDef is true.
91 bool
92 isEmittedWithConstantInitializer(const VarDecl *VD,
93 bool InspectInitForWeakDef = false) const;
94
95 virtual bool requiresArrayCookie(const CXXDeleteExpr *E, QualType eltType);
96 virtual bool requiresArrayCookie(const CXXNewExpr *E);
97
98 /// Determine whether there's something special about the rules of
99 /// the ABI tell us that 'this' is a complete object within the
100 /// given function. Obvious common logic like being defined on a
101 /// final class will have been taken care of by the caller.
102 virtual bool isThisCompleteObject(GlobalDecl GD) const = 0;
103
104 virtual bool constructorsAndDestructorsReturnThis() const {
105 return CGM.getCodeGenOpts().CtorDtorReturnThis;
106 }
107
108public:
109
110 virtual ~CGCXXABI();
111
112 /// Gets the mangle context.
113 MangleContext &getMangleContext() {
114 return *MangleCtx;
115 }
116
117 /// Returns true if the given constructor or destructor is one of the
118 /// kinds that the ABI says returns 'this' (only applies when called
119 /// non-virtually for destructors).
120 ///
121 /// There currently is no way to indicate if a destructor returns 'this'
122 /// when called virtually, and code generation does not support the case.
123 virtual bool HasThisReturn(GlobalDecl GD) const {
124 if (isa<CXXConstructorDecl>(Val: GD.getDecl()) ||
125 (isa<CXXDestructorDecl>(Val: GD.getDecl()) &&
126 GD.getDtorType() != Dtor_Deleting))
127 return constructorsAndDestructorsReturnThis();
128 return false;
129 }
130
131 virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; }
132
133 virtual bool useSinitAndSterm() const { return false; }
134
135 /// Returns true if the target allows calling a function through a pointer
136 /// with a different signature than the actual function (or equivalently,
137 /// bitcasting a function or function pointer to a different function type).
138 /// In principle in the most general case this could depend on the target, the
139 /// calling convention, and the actual types of the arguments and return
140 /// value. Here it just means whether the signature mismatch could *ever* be
141 /// allowed; in other words, does the target do strict checking of signatures
142 /// for all calls.
143 virtual bool canCallMismatchedFunctionType() const { return true; }
144
145 /// If the C++ ABI requires the given type be returned in a particular way,
146 /// this method sets RetAI and returns true.
147 virtual bool classifyReturnType(CGFunctionInfo &FI) const = 0;
148
149 /// Specify how one should pass an argument of a record type.
150 enum RecordArgABI {
151 /// Pass it using the normal C aggregate rules for the ABI, potentially
152 /// introducing extra copies and passing some or all of it in registers.
153 RAA_Default = 0,
154
155 /// Pass it on the stack using its defined layout. The argument must be
156 /// evaluated directly into the correct stack position in the arguments area,
157 /// and the call machinery must not move it or introduce extra copies.
158 RAA_DirectInMemory,
159
160 /// Pass it as a pointer to temporary memory.
161 RAA_Indirect
162 };
163
164 /// Returns how an argument of the given record type should be passed.
165 virtual RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const = 0;
166
167 /// Returns true if the implicit 'sret' parameter comes after the implicit
168 /// 'this' parameter of C++ instance methods.
169 virtual bool isSRetParameterAfterThis() const { return false; }
170
171 /// Returns true if the ABI permits the argument to be a homogeneous
172 /// aggregate.
173 virtual bool
174 isPermittedToBeHomogeneousAggregate(const CXXRecordDecl *RD) const {
175 return true;
176 };
177
178 /// Find the LLVM type used to represent the given member pointer
179 /// type.
180 virtual llvm::Type *
181 ConvertMemberPointerType(const MemberPointerType *MPT);
182
183 /// Load a member function from an object and a member function
184 /// pointer. Apply the this-adjustment and set 'This' to the
185 /// adjusted value.
186 virtual CGCallee EmitLoadOfMemberFunctionPointer(
187 CodeGenFunction &CGF, const Expr *E, Address This,
188 llvm::Value *&ThisPtrForCall, llvm::Value *MemPtr,
189 const MemberPointerType *MPT);
190
191 /// Calculate an l-value from an object and a data member pointer.
192 virtual llvm::Value *
193 EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
194 Address Base, llvm::Value *MemPtr,
195 const MemberPointerType *MPT, bool IsInBounds);
196
197 /// Perform a derived-to-base, base-to-derived, or bitcast member
198 /// pointer conversion.
199 virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
200 const CastExpr *E,
201 llvm::Value *Src);
202
203 /// Perform a derived-to-base, base-to-derived, or bitcast member
204 /// pointer conversion on a constant value.
205 virtual llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
206 llvm::Constant *Src);
207
208 /// Return true if the given member pointer can be zero-initialized
209 /// (in the C++ sense) with an LLVM zeroinitializer.
210 virtual bool isZeroInitializable(const MemberPointerType *MPT);
211
212 /// Return whether or not a member pointers type is convertible to an IR type.
213 virtual bool isMemberPointerConvertible(const MemberPointerType *MPT) const {
214 return true;
215 }
216
217 /// Create a null member pointer of the given type.
218 virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT);
219
220 /// Create a member pointer for the given method.
221 virtual llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD);
222
223 /// Create a member pointer for the given field.
224 virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
225 CharUnits offset);
226
227 /// Create a member pointer for the given member pointer constant.
228 virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT);
229
230 /// Emit a comparison between two member pointers. Returns an i1.
231 virtual llvm::Value *
232 EmitMemberPointerComparison(CodeGenFunction &CGF,
233 llvm::Value *L,
234 llvm::Value *R,
235 const MemberPointerType *MPT,
236 bool Inequality);
237
238 /// Determine if a member pointer is non-null. Returns an i1.
239 virtual llvm::Value *
240 EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
241 llvm::Value *MemPtr,
242 const MemberPointerType *MPT);
243
244protected:
245 /// A utility method for computing the offset required for the given
246 /// base-to-derived or derived-to-base member-pointer conversion.
247 /// Does not handle virtual conversions (in case we ever fully
248 /// support an ABI that allows this). Returns null if no adjustment
249 /// is required.
250 llvm::Constant *getMemberPointerAdjustment(const CastExpr *E);
251
252public:
253 virtual void emitVirtualObjectDelete(CodeGenFunction &CGF,
254 const CXXDeleteExpr *DE,
255 Address Ptr, QualType ElementType,
256 const CXXDestructorDecl *Dtor) = 0;
257 virtual void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) = 0;
258 virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0;
259 virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; }
260
261 /// Determine whether it's possible to emit a vtable for \p RD, even
262 /// though we do not know that the vtable has been marked as used by semantic
263 /// analysis.
264 virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const = 0;
265
266 virtual void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) = 0;
267
268 virtual llvm::CallInst *
269 emitTerminateForUnexpectedException(CodeGenFunction &CGF,
270 llvm::Value *Exn);
271
272 virtual llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) = 0;
273 virtual CatchTypeInfo
274 getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) = 0;
275 virtual CatchTypeInfo getCatchAllTypeInfo();
276
277 virtual bool shouldTypeidBeNullChecked(QualType SrcRecordTy) = 0;
278 virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0;
279 virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
280 Address ThisPtr,
281 llvm::Type *StdTypeInfoPtrTy) = 0;
282
283 virtual bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
284 QualType SrcRecordTy) = 0;
285 virtual bool shouldEmitExactDynamicCast(QualType DestRecordTy) = 0;
286
287 virtual llvm::Value *emitDynamicCastCall(CodeGenFunction &CGF, Address Value,
288 QualType SrcRecordTy,
289 QualType DestTy,
290 QualType DestRecordTy,
291 llvm::BasicBlock *CastEnd) = 0;
292
293 virtual llvm::Value *emitDynamicCastToVoid(CodeGenFunction &CGF,
294 Address Value,
295 QualType SrcRecordTy) = 0;
296
297 /// Emit a dynamic_cast from SrcRecordTy to DestRecordTy. The cast fails if
298 /// the dynamic type of Value is not exactly DestRecordTy.
299 virtual llvm::Value *emitExactDynamicCast(CodeGenFunction &CGF, Address Value,
300 QualType SrcRecordTy,
301 QualType DestTy,
302 QualType DestRecordTy,
303 llvm::BasicBlock *CastSuccess,
304 llvm::BasicBlock *CastFail) = 0;
305
306 virtual bool EmitBadCastCall(CodeGenFunction &CGF) = 0;
307
308 virtual llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF,
309 Address This,
310 const CXXRecordDecl *ClassDecl,
311 const CXXRecordDecl *BaseClassDecl) = 0;
312
313 virtual llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
314 const CXXRecordDecl *RD);
315
316 /// Emit the code to initialize hidden members required
317 /// to handle virtual inheritance, if needed by the ABI.
318 virtual void
319 initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
320 const CXXRecordDecl *RD) {}
321
322 /// Emit constructor variants required by this ABI.
323 virtual void EmitCXXConstructors(const CXXConstructorDecl *D) = 0;
324
325 /// Additional implicit arguments to add to the beginning (Prefix) and end
326 /// (Suffix) of a constructor / destructor arg list.
327 ///
328 /// Note that Prefix should actually be inserted *after* the first existing
329 /// arg; `this` arguments always come first.
330 struct AddedStructorArgs {
331 struct Arg {
332 llvm::Value *Value;
333 QualType Type;
334 };
335 SmallVector<Arg, 1> Prefix;
336 SmallVector<Arg, 1> Suffix;
337 AddedStructorArgs() = default;
338 AddedStructorArgs(SmallVector<Arg, 1> P, SmallVector<Arg, 1> S)
339 : Prefix(std::move(P)), Suffix(std::move(S)) {}
340 static AddedStructorArgs prefix(SmallVector<Arg, 1> Args) {
341 return {std::move(Args), {}};
342 }
343 static AddedStructorArgs suffix(SmallVector<Arg, 1> Args) {
344 return {{}, std::move(Args)};
345 }
346 };
347
348 /// Similar to AddedStructorArgs, but only notes the number of additional
349 /// arguments.
350 struct AddedStructorArgCounts {
351 unsigned Prefix = 0;
352 unsigned Suffix = 0;
353 AddedStructorArgCounts() = default;
354 AddedStructorArgCounts(unsigned P, unsigned S) : Prefix(P), Suffix(S) {}
355 static AddedStructorArgCounts prefix(unsigned N) { return {N, 0}; }
356 static AddedStructorArgCounts suffix(unsigned N) { return {0, N}; }
357 };
358
359 /// Build the signature of the given constructor or destructor variant by
360 /// adding any required parameters. For convenience, ArgTys has been
361 /// initialized with the type of 'this'.
362 virtual AddedStructorArgCounts
363 buildStructorSignature(GlobalDecl GD,
364 SmallVectorImpl<CanQualType> &ArgTys) = 0;
365
366 /// Returns true if the given destructor type should be emitted as a linkonce
367 /// delegating thunk, regardless of whether the dtor is defined in this TU or
368 /// not.
369 virtual bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
370 CXXDtorType DT) const = 0;
371
372 virtual void setCXXDestructorDLLStorage(llvm::GlobalValue *GV,
373 const CXXDestructorDecl *Dtor,
374 CXXDtorType DT) const;
375
376 virtual llvm::GlobalValue::LinkageTypes
377 getCXXDestructorLinkage(GVALinkage Linkage, const CXXDestructorDecl *Dtor,
378 CXXDtorType DT) const;
379
380 /// Emit destructor variants required by this ABI.
381 virtual void EmitCXXDestructors(const CXXDestructorDecl *D) = 0;
382
383 /// Get the type of the implicit "this" parameter used by a method. May return
384 /// zero if no specific type is applicable, e.g. if the ABI expects the "this"
385 /// parameter to point to some artificial offset in a complete object due to
386 /// vbases being reordered.
387 virtual const CXXRecordDecl *getThisArgumentTypeForMethod(GlobalDecl GD) {
388 return cast<CXXMethodDecl>(Val: GD.getDecl())->getParent();
389 }
390
391 /// Perform ABI-specific "this" argument adjustment required prior to
392 /// a call of a virtual function.
393 /// The "VirtualCall" argument is true iff the call itself is virtual.
394 virtual Address
395 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
396 Address This, bool VirtualCall) {
397 return This;
398 }
399
400 /// Build a parameter variable suitable for 'this'.
401 void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params);
402
403 /// Insert any ABI-specific implicit parameters into the parameter list for a
404 /// function. This generally involves extra data for constructors and
405 /// destructors.
406 ///
407 /// ABIs may also choose to override the return type, which has been
408 /// initialized with the type of 'this' if HasThisReturn(CGF.CurGD) is true or
409 /// the formal return type of the function otherwise.
410 virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
411 FunctionArgList &Params) = 0;
412
413 /// Get the ABI-specific "this" parameter adjustment to apply in the prologue
414 /// of a virtual function.
415 virtual CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
416 return CharUnits::Zero();
417 }
418
419 /// Emit the ABI-specific prolog for the function.
420 virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0;
421
422 virtual AddedStructorArgs
423 getImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D,
424 CXXCtorType Type, bool ForVirtualBase,
425 bool Delegating) = 0;
426
427 /// Add any ABI-specific implicit arguments needed to call a constructor.
428 ///
429 /// \return The number of arguments added at the beginning and end of the
430 /// call, which is typically zero or one.
431 AddedStructorArgCounts
432 addImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D,
433 CXXCtorType Type, bool ForVirtualBase,
434 bool Delegating, CallArgList &Args);
435
436 /// Get the implicit (second) parameter that comes after the "this" pointer,
437 /// or nullptr if there is isn't one.
438 virtual llvm::Value *
439 getCXXDestructorImplicitParam(CodeGenFunction &CGF,
440 const CXXDestructorDecl *DD, CXXDtorType Type,
441 bool ForVirtualBase, bool Delegating) = 0;
442
443 /// Emit the destructor call.
444 virtual void EmitDestructorCall(CodeGenFunction &CGF,
445 const CXXDestructorDecl *DD, CXXDtorType Type,
446 bool ForVirtualBase, bool Delegating,
447 Address This, QualType ThisTy) = 0;
448
449 /// Emits the VTable definitions required for the given record type.
450 virtual void emitVTableDefinitions(CodeGenVTables &CGVT,
451 const CXXRecordDecl *RD) = 0;
452
453 /// Checks if ABI requires extra virtual offset for vtable field.
454 virtual bool
455 isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF,
456 CodeGenFunction::VPtr Vptr) = 0;
457
458 /// Checks if ABI requires to initialize vptrs for given dynamic class.
459 virtual bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) = 0;
460
461 /// Get the address point of the vtable for the given base subobject.
462 virtual llvm::Constant *
463 getVTableAddressPoint(BaseSubobject Base,
464 const CXXRecordDecl *VTableClass) = 0;
465
466 /// Get the address point of the vtable for the given base subobject while
467 /// building a constructor or a destructor.
468 virtual llvm::Value *
469 getVTableAddressPointInStructor(CodeGenFunction &CGF, const CXXRecordDecl *RD,
470 BaseSubobject Base,
471 const CXXRecordDecl *NearestVBase) = 0;
472
473 /// Get the address of the vtable for the given record decl which should be
474 /// used for the vptr at the given offset in RD.
475 virtual llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
476 CharUnits VPtrOffset) = 0;
477
478 /// Build a virtual function pointer in the ABI-specific way.
479 virtual CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF,
480 GlobalDecl GD, Address This,
481 llvm::Type *Ty,
482 SourceLocation Loc) = 0;
483
484 using DeleteOrMemberCallExpr =
485 llvm::PointerUnion<const CXXDeleteExpr *, const CXXMemberCallExpr *>;
486
487 /// Emit the ABI-specific virtual destructor call.
488 virtual llvm::Value *
489 EmitVirtualDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *Dtor,
490 CXXDtorType DtorType, Address This,
491 DeleteOrMemberCallExpr E,
492 llvm::CallBase **CallOrInvoke) = 0;
493
494 virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF,
495 GlobalDecl GD,
496 CallArgList &CallArgs) {}
497
498 /// Emit any tables needed to implement virtual inheritance. For Itanium,
499 /// this emits virtual table tables. For the MSVC++ ABI, this emits virtual
500 /// base tables.
501 virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD) = 0;
502
503 virtual bool exportThunk() = 0;
504 virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
505 GlobalDecl GD, bool ReturnAdjustment) = 0;
506
507 virtual llvm::Value *
508 performThisAdjustment(CodeGenFunction &CGF, Address This,
509 const CXXRecordDecl *UnadjustedClass,
510 const ThunkInfo &TI) = 0;
511
512 virtual llvm::Value *
513 performReturnAdjustment(CodeGenFunction &CGF, Address Ret,
514 const CXXRecordDecl *UnadjustedClass,
515 const ReturnAdjustment &RA) = 0;
516
517 virtual void EmitReturnFromThunk(CodeGenFunction &CGF,
518 RValue RV, QualType ResultType);
519
520 virtual size_t getSrcArgforCopyCtor(const CXXConstructorDecl *,
521 FunctionArgList &Args) const = 0;
522
523 /// Gets the offsets of all the virtual base pointers in a given class.
524 virtual std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD);
525
526 /// Gets the pure virtual member call function.
527 virtual StringRef GetPureVirtualCallName() = 0;
528
529 /// Gets the deleted virtual member call name.
530 virtual StringRef GetDeletedVirtualCallName() = 0;
531
532 /**************************** Array cookies ******************************/
533
534 /// Returns the extra size required in order to store the array
535 /// cookie for the given new-expression. May return 0 to indicate that no
536 /// array cookie is required.
537 ///
538 /// Several cases are filtered out before this method is called:
539 /// - non-array allocations never need a cookie
540 /// - calls to \::operator new(size_t, void*) never need a cookie
541 ///
542 /// \param expr - the new-expression being allocated.
543 virtual CharUnits GetArrayCookieSize(const CXXNewExpr *expr);
544
545 /// Initialize the array cookie for the given allocation.
546 ///
547 /// \param NewPtr - a char* which is the presumed-non-null
548 /// return value of the allocation function
549 /// \param NumElements - the computed number of elements,
550 /// potentially collapsed from the multidimensional array case;
551 /// always a size_t
552 /// \param ElementType - the base element allocated type,
553 /// i.e. the allocated type after stripping all array types
554 virtual Address InitializeArrayCookie(CodeGenFunction &CGF,
555 Address NewPtr,
556 llvm::Value *NumElements,
557 const CXXNewExpr *expr,
558 QualType ElementType);
559
560 /// Reads the array cookie associated with the given pointer,
561 /// if it has one.
562 ///
563 /// \param Ptr - a pointer to the first element in the array
564 /// \param ElementType - the base element type of elements of the array
565 /// \param NumElements - an out parameter which will be initialized
566 /// with the number of elements allocated, or zero if there is no
567 /// cookie
568 /// \param AllocPtr - an out parameter which will be initialized
569 /// with a char* pointing to the address returned by the allocation
570 /// function
571 /// \param CookieSize - an out parameter which will be initialized
572 /// with the size of the cookie, or zero if there is no cookie
573 virtual void ReadArrayCookie(CodeGenFunction &CGF, Address Ptr,
574 const CXXDeleteExpr *expr,
575 QualType ElementType, llvm::Value *&NumElements,
576 llvm::Value *&AllocPtr, CharUnits &CookieSize);
577
578 /// Return whether the given global decl needs a VTT parameter.
579 virtual bool NeedsVTTParameter(GlobalDecl GD);
580
581protected:
582 /// Returns the extra size required in order to store the array
583 /// cookie for the given type. Assumes that an array cookie is
584 /// required.
585 virtual CharUnits getArrayCookieSizeImpl(QualType elementType);
586
587 /// Reads the array cookie for an allocation which is known to have one.
588 /// This is called by the standard implementation of ReadArrayCookie.
589 ///
590 /// \param ptr - a pointer to the allocation made for an array, as a char*
591 /// \param cookieSize - the computed cookie size of an array
592 ///
593 /// Other parameters are as above.
594 ///
595 /// \return a size_t
596 virtual llvm::Value *readArrayCookieImpl(CodeGenFunction &IGF, Address ptr,
597 CharUnits cookieSize);
598
599public:
600
601 /*************************** Static local guards ****************************/
602
603 /// Emits the guarded initializer and destructor setup for the given
604 /// variable, given that it couldn't be emitted as a constant.
605 /// If \p PerformInit is false, the initialization has been folded to a
606 /// constant and should not be performed.
607 ///
608 /// The variable may be:
609 /// - a static local variable
610 /// - a static data member of a class template instantiation
611 virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
612 llvm::GlobalVariable *DeclPtr,
613 bool PerformInit) = 0;
614
615 /// Emit code to force the execution of a destructor during global
616 /// teardown. The default implementation of this uses atexit.
617 ///
618 /// \param Dtor - a function taking a single pointer argument
619 /// \param Addr - a pointer to pass to the destructor function.
620 virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
621 llvm::FunctionCallee Dtor,
622 llvm::Constant *Addr) = 0;
623
624 /*************************** thread_local initialization ********************/
625
626 /// Emits ABI-required functions necessary to initialize thread_local
627 /// variables in this translation unit.
628 ///
629 /// \param CXXThreadLocals - The thread_local declarations in this translation
630 /// unit.
631 /// \param CXXThreadLocalInits - If this translation unit contains any
632 /// non-constant initialization or non-trivial destruction for
633 /// thread_local variables, a list of functions to perform the
634 /// initialization.
635 virtual void EmitThreadLocalInitFuncs(
636 CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals,
637 ArrayRef<llvm::Function *> CXXThreadLocalInits,
638 ArrayRef<const VarDecl *> CXXThreadLocalInitVars) = 0;
639
640 // Determine if references to thread_local global variables can be made
641 // directly or require access through a thread wrapper function.
642 virtual bool usesThreadWrapperFunction(const VarDecl *VD) const = 0;
643
644 /// Emit a reference to a non-local thread_local variable (including
645 /// triggering the initialization of all thread_local variables in its
646 /// translation unit).
647 virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
648 const VarDecl *VD,
649 QualType LValType) = 0;
650
651 /// Emit a single constructor/destructor with the given type from a C++
652 /// constructor Decl.
653 virtual void emitCXXStructor(GlobalDecl GD) = 0;
654
655 /// Load a vtable from This, an object of polymorphic type RD, or from one of
656 /// its virtual bases if it does not have its own vtable. Returns the vtable
657 /// and the class from which the vtable was loaded.
658 virtual std::pair<llvm::Value *, const CXXRecordDecl *>
659 LoadVTablePtr(CodeGenFunction &CGF, Address This,
660 const CXXRecordDecl *RD) = 0;
661};
662
663// Create an instance of a C++ ABI class:
664
665/// Creates an Itanium-family ABI.
666CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM);
667
668/// Creates a Microsoft-family ABI.
669CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM);
670
671struct CatchRetScope final : EHScopeStack::Cleanup {
672 llvm::CatchPadInst *CPI;
673
674 CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {}
675
676 void Emit(CodeGenFunction &CGF, Flags flags) override {
677 llvm::BasicBlock *BB = CGF.createBasicBlock(name: "catchret.dest");
678 CGF.Builder.CreateCatchRet(CatchPad: CPI, BB);
679 CGF.EmitBlock(BB);
680 }
681};
682}
683}
684
685#endif
686