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);
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(bool IsDeref,
278 QualType SrcRecordTy) = 0;
279 virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0;
280 virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
281 Address ThisPtr,
282 llvm::Type *StdTypeInfoPtrTy) = 0;
283
284 virtual bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
285 QualType SrcRecordTy) = 0;
286 virtual bool shouldEmitExactDynamicCast(QualType DestRecordTy) = 0;
287
288 virtual llvm::Value *emitDynamicCastCall(CodeGenFunction &CGF, Address Value,
289 QualType SrcRecordTy,
290 QualType DestTy,
291 QualType DestRecordTy,
292 llvm::BasicBlock *CastEnd) = 0;
293
294 virtual llvm::Value *emitDynamicCastToVoid(CodeGenFunction &CGF,
295 Address Value,
296 QualType SrcRecordTy) = 0;
297
298 /// Emit a dynamic_cast from SrcRecordTy to DestRecordTy. The cast fails if
299 /// the dynamic type of Value is not exactly DestRecordTy.
300 virtual llvm::Value *emitExactDynamicCast(CodeGenFunction &CGF, Address Value,
301 QualType SrcRecordTy,
302 QualType DestTy,
303 QualType DestRecordTy,
304 llvm::BasicBlock *CastSuccess,
305 llvm::BasicBlock *CastFail) = 0;
306
307 virtual bool EmitBadCastCall(CodeGenFunction &CGF) = 0;
308
309 virtual llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF,
310 Address This,
311 const CXXRecordDecl *ClassDecl,
312 const CXXRecordDecl *BaseClassDecl) = 0;
313
314 virtual llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
315 const CXXRecordDecl *RD);
316
317 /// Emit the code to initialize hidden members required
318 /// to handle virtual inheritance, if needed by the ABI.
319 virtual void
320 initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
321 const CXXRecordDecl *RD) {}
322
323 /// Emit constructor variants required by this ABI.
324 virtual void EmitCXXConstructors(const CXXConstructorDecl *D) = 0;
325
326 /// Additional implicit arguments to add to the beginning (Prefix) and end
327 /// (Suffix) of a constructor / destructor arg list.
328 ///
329 /// Note that Prefix should actually be inserted *after* the first existing
330 /// arg; `this` arguments always come first.
331 struct AddedStructorArgs {
332 struct Arg {
333 llvm::Value *Value;
334 QualType Type;
335 };
336 SmallVector<Arg, 1> Prefix;
337 SmallVector<Arg, 1> Suffix;
338 AddedStructorArgs() = default;
339 AddedStructorArgs(SmallVector<Arg, 1> P, SmallVector<Arg, 1> S)
340 : Prefix(std::move(P)), Suffix(std::move(S)) {}
341 static AddedStructorArgs prefix(SmallVector<Arg, 1> Args) {
342 return {std::move(Args), {}};
343 }
344 static AddedStructorArgs suffix(SmallVector<Arg, 1> Args) {
345 return {{}, std::move(Args)};
346 }
347 };
348
349 /// Similar to AddedStructorArgs, but only notes the number of additional
350 /// arguments.
351 struct AddedStructorArgCounts {
352 unsigned Prefix = 0;
353 unsigned Suffix = 0;
354 AddedStructorArgCounts() = default;
355 AddedStructorArgCounts(unsigned P, unsigned S) : Prefix(P), Suffix(S) {}
356 static AddedStructorArgCounts prefix(unsigned N) { return {N, 0}; }
357 static AddedStructorArgCounts suffix(unsigned N) { return {0, N}; }
358 };
359
360 /// Build the signature of the given constructor or destructor variant by
361 /// adding any required parameters. For convenience, ArgTys has been
362 /// initialized with the type of 'this'.
363 virtual AddedStructorArgCounts
364 buildStructorSignature(GlobalDecl GD,
365 SmallVectorImpl<CanQualType> &ArgTys) = 0;
366
367 /// Returns true if the given destructor type should be emitted as a linkonce
368 /// delegating thunk, regardless of whether the dtor is defined in this TU or
369 /// not.
370 virtual bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
371 CXXDtorType DT) const = 0;
372
373 virtual void setCXXDestructorDLLStorage(llvm::GlobalValue *GV,
374 const CXXDestructorDecl *Dtor,
375 CXXDtorType DT) const;
376
377 virtual llvm::GlobalValue::LinkageTypes
378 getCXXDestructorLinkage(GVALinkage Linkage, const CXXDestructorDecl *Dtor,
379 CXXDtorType DT) const;
380
381 /// Emit destructor variants required by this ABI.
382 virtual void EmitCXXDestructors(const CXXDestructorDecl *D) = 0;
383
384 /// Get the type of the implicit "this" parameter used by a method. May return
385 /// zero if no specific type is applicable, e.g. if the ABI expects the "this"
386 /// parameter to point to some artificial offset in a complete object due to
387 /// vbases being reordered.
388 virtual const CXXRecordDecl *getThisArgumentTypeForMethod(GlobalDecl GD) {
389 return cast<CXXMethodDecl>(Val: GD.getDecl())->getParent();
390 }
391
392 /// Perform ABI-specific "this" argument adjustment required prior to
393 /// a call of a virtual function.
394 /// The "VirtualCall" argument is true iff the call itself is virtual.
395 virtual Address
396 adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
397 Address This, bool VirtualCall) {
398 return This;
399 }
400
401 /// Build a parameter variable suitable for 'this'.
402 void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params);
403
404 /// Insert any ABI-specific implicit parameters into the parameter list for a
405 /// function. This generally involves extra data for constructors and
406 /// destructors.
407 ///
408 /// ABIs may also choose to override the return type, which has been
409 /// initialized with the type of 'this' if HasThisReturn(CGF.CurGD) is true or
410 /// the formal return type of the function otherwise.
411 virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
412 FunctionArgList &Params) = 0;
413
414 /// Get the ABI-specific "this" parameter adjustment to apply in the prologue
415 /// of a virtual function.
416 virtual CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
417 return CharUnits::Zero();
418 }
419
420 /// Emit the ABI-specific prolog for the function.
421 virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0;
422
423 virtual AddedStructorArgs
424 getImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D,
425 CXXCtorType Type, bool ForVirtualBase,
426 bool Delegating) = 0;
427
428 /// Add any ABI-specific implicit arguments needed to call a constructor.
429 ///
430 /// \return The number of arguments added at the beginning and end of the
431 /// call, which is typically zero or one.
432 AddedStructorArgCounts
433 addImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D,
434 CXXCtorType Type, bool ForVirtualBase,
435 bool Delegating, CallArgList &Args);
436
437 /// Get the implicit (second) parameter that comes after the "this" pointer,
438 /// or nullptr if there is isn't one.
439 virtual llvm::Value *
440 getCXXDestructorImplicitParam(CodeGenFunction &CGF,
441 const CXXDestructorDecl *DD, CXXDtorType Type,
442 bool ForVirtualBase, bool Delegating) = 0;
443
444 /// Emit the destructor call.
445 virtual void EmitDestructorCall(CodeGenFunction &CGF,
446 const CXXDestructorDecl *DD, CXXDtorType Type,
447 bool ForVirtualBase, bool Delegating,
448 Address This, QualType ThisTy) = 0;
449
450 /// Emits the VTable definitions required for the given record type.
451 virtual void emitVTableDefinitions(CodeGenVTables &CGVT,
452 const CXXRecordDecl *RD) = 0;
453
454 /// Checks if ABI requires extra virtual offset for vtable field.
455 virtual bool
456 isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF,
457 CodeGenFunction::VPtr Vptr) = 0;
458
459 /// Checks if ABI requires to initialize vptrs for given dynamic class.
460 virtual bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) = 0;
461
462 /// Get the address point of the vtable for the given base subobject.
463 virtual llvm::Constant *
464 getVTableAddressPoint(BaseSubobject Base,
465 const CXXRecordDecl *VTableClass) = 0;
466
467 /// Get the address point of the vtable for the given base subobject while
468 /// building a constructor or a destructor.
469 virtual llvm::Value *
470 getVTableAddressPointInStructor(CodeGenFunction &CGF, const CXXRecordDecl *RD,
471 BaseSubobject Base,
472 const CXXRecordDecl *NearestVBase) = 0;
473
474 /// Get the address of the vtable for the given record decl which should be
475 /// used for the vptr at the given offset in RD.
476 virtual llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
477 CharUnits VPtrOffset) = 0;
478
479 /// Build a virtual function pointer in the ABI-specific way.
480 virtual CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF,
481 GlobalDecl GD, Address This,
482 llvm::Type *Ty,
483 SourceLocation Loc) = 0;
484
485 using DeleteOrMemberCallExpr =
486 llvm::PointerUnion<const CXXDeleteExpr *, const CXXMemberCallExpr *>;
487
488 /// Emit the ABI-specific virtual destructor call.
489 virtual llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
490 const CXXDestructorDecl *Dtor,
491 CXXDtorType DtorType,
492 Address This,
493 DeleteOrMemberCallExpr E) = 0;
494
495 virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF,
496 GlobalDecl GD,
497 CallArgList &CallArgs) {}
498
499 /// Emit any tables needed to implement virtual inheritance. For Itanium,
500 /// this emits virtual table tables. For the MSVC++ ABI, this emits virtual
501 /// base tables.
502 virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD) = 0;
503
504 virtual bool exportThunk() = 0;
505 virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
506 GlobalDecl GD, bool ReturnAdjustment) = 0;
507
508 virtual llvm::Value *performThisAdjustment(CodeGenFunction &CGF,
509 Address This,
510 const ThisAdjustment &TA) = 0;
511
512 virtual llvm::Value *performReturnAdjustment(CodeGenFunction &CGF,
513 Address Ret,
514 const ReturnAdjustment &RA) = 0;
515
516 virtual void EmitReturnFromThunk(CodeGenFunction &CGF,
517 RValue RV, QualType ResultType);
518
519 virtual size_t getSrcArgforCopyCtor(const CXXConstructorDecl *,
520 FunctionArgList &Args) const = 0;
521
522 /// Gets the offsets of all the virtual base pointers in a given class.
523 virtual std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD);
524
525 /// Gets the pure virtual member call function.
526 virtual StringRef GetPureVirtualCallName() = 0;
527
528 /// Gets the deleted virtual member call name.
529 virtual StringRef GetDeletedVirtualCallName() = 0;
530
531 /**************************** Array cookies ******************************/
532
533 /// Returns the extra size required in order to store the array
534 /// cookie for the given new-expression. May return 0 to indicate that no
535 /// array cookie is required.
536 ///
537 /// Several cases are filtered out before this method is called:
538 /// - non-array allocations never need a cookie
539 /// - calls to \::operator new(size_t, void*) never need a cookie
540 ///
541 /// \param expr - the new-expression being allocated.
542 virtual CharUnits GetArrayCookieSize(const CXXNewExpr *expr);
543
544 /// Initialize the array cookie for the given allocation.
545 ///
546 /// \param NewPtr - a char* which is the presumed-non-null
547 /// return value of the allocation function
548 /// \param NumElements - the computed number of elements,
549 /// potentially collapsed from the multidimensional array case;
550 /// always a size_t
551 /// \param ElementType - the base element allocated type,
552 /// i.e. the allocated type after stripping all array types
553 virtual Address InitializeArrayCookie(CodeGenFunction &CGF,
554 Address NewPtr,
555 llvm::Value *NumElements,
556 const CXXNewExpr *expr,
557 QualType ElementType);
558
559 /// Reads the array cookie associated with the given pointer,
560 /// if it has one.
561 ///
562 /// \param Ptr - a pointer to the first element in the array
563 /// \param ElementType - the base element type of elements of the array
564 /// \param NumElements - an out parameter which will be initialized
565 /// with the number of elements allocated, or zero if there is no
566 /// cookie
567 /// \param AllocPtr - an out parameter which will be initialized
568 /// with a char* pointing to the address returned by the allocation
569 /// function
570 /// \param CookieSize - an out parameter which will be initialized
571 /// with the size of the cookie, or zero if there is no cookie
572 virtual void ReadArrayCookie(CodeGenFunction &CGF, Address Ptr,
573 const CXXDeleteExpr *expr,
574 QualType ElementType, llvm::Value *&NumElements,
575 llvm::Value *&AllocPtr, CharUnits &CookieSize);
576
577 /// Return whether the given global decl needs a VTT parameter.
578 virtual bool NeedsVTTParameter(GlobalDecl GD);
579
580protected:
581 /// Returns the extra size required in order to store the array
582 /// cookie for the given type. Assumes that an array cookie is
583 /// required.
584 virtual CharUnits getArrayCookieSizeImpl(QualType elementType);
585
586 /// Reads the array cookie for an allocation which is known to have one.
587 /// This is called by the standard implementation of ReadArrayCookie.
588 ///
589 /// \param ptr - a pointer to the allocation made for an array, as a char*
590 /// \param cookieSize - the computed cookie size of an array
591 ///
592 /// Other parameters are as above.
593 ///
594 /// \return a size_t
595 virtual llvm::Value *readArrayCookieImpl(CodeGenFunction &IGF, Address ptr,
596 CharUnits cookieSize);
597
598public:
599
600 /*************************** Static local guards ****************************/
601
602 /// Emits the guarded initializer and destructor setup for the given
603 /// variable, given that it couldn't be emitted as a constant.
604 /// If \p PerformInit is false, the initialization has been folded to a
605 /// constant and should not be performed.
606 ///
607 /// The variable may be:
608 /// - a static local variable
609 /// - a static data member of a class template instantiation
610 virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
611 llvm::GlobalVariable *DeclPtr,
612 bool PerformInit) = 0;
613
614 /// Emit code to force the execution of a destructor during global
615 /// teardown. The default implementation of this uses atexit.
616 ///
617 /// \param Dtor - a function taking a single pointer argument
618 /// \param Addr - a pointer to pass to the destructor function.
619 virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
620 llvm::FunctionCallee Dtor,
621 llvm::Constant *Addr) = 0;
622
623 /*************************** thread_local initialization ********************/
624
625 /// Emits ABI-required functions necessary to initialize thread_local
626 /// variables in this translation unit.
627 ///
628 /// \param CXXThreadLocals - The thread_local declarations in this translation
629 /// unit.
630 /// \param CXXThreadLocalInits - If this translation unit contains any
631 /// non-constant initialization or non-trivial destruction for
632 /// thread_local variables, a list of functions to perform the
633 /// initialization.
634 virtual void EmitThreadLocalInitFuncs(
635 CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals,
636 ArrayRef<llvm::Function *> CXXThreadLocalInits,
637 ArrayRef<const VarDecl *> CXXThreadLocalInitVars) = 0;
638
639 // Determine if references to thread_local global variables can be made
640 // directly or require access through a thread wrapper function.
641 virtual bool usesThreadWrapperFunction(const VarDecl *VD) const = 0;
642
643 /// Emit a reference to a non-local thread_local variable (including
644 /// triggering the initialization of all thread_local variables in its
645 /// translation unit).
646 virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
647 const VarDecl *VD,
648 QualType LValType) = 0;
649
650 /// Emit a single constructor/destructor with the given type from a C++
651 /// constructor Decl.
652 virtual void emitCXXStructor(GlobalDecl GD) = 0;
653
654 /// Load a vtable from This, an object of polymorphic type RD, or from one of
655 /// its virtual bases if it does not have its own vtable. Returns the vtable
656 /// and the class from which the vtable was loaded.
657 virtual std::pair<llvm::Value *, const CXXRecordDecl *>
658 LoadVTablePtr(CodeGenFunction &CGF, Address This,
659 const CXXRecordDecl *RD) = 0;
660};
661
662// Create an instance of a C++ ABI class:
663
664/// Creates an Itanium-family ABI.
665CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM);
666
667/// Creates a Microsoft-family ABI.
668CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM);
669
670struct CatchRetScope final : EHScopeStack::Cleanup {
671 llvm::CatchPadInst *CPI;
672
673 CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {}
674
675 void Emit(CodeGenFunction &CGF, Flags flags) override {
676 llvm::BasicBlock *BB = CGF.createBasicBlock(name: "catchret.dest");
677 CGF.Builder.CreateCatchRet(CatchPad: CPI, BB);
678 CGF.EmitBlock(BB);
679 }
680};
681}
682}
683
684#endif
685

source code of clang/lib/CodeGen/CGCXXABI.h