1 | //===----- CGCXXABI.h - Interface to C++ ABIs -------------------*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | // |
9 | // This provides an abstract class for C++ code generation. Concrete subclasses |
10 | // of this implement code generation for specific C++ ABIs. |
11 | // |
12 | //===----------------------------------------------------------------------===// |
13 | |
14 | #ifndef LLVM_CLANG_LIB_CODEGEN_CGCXXABI_H |
15 | #define LLVM_CLANG_LIB_CODEGEN_CGCXXABI_H |
16 | |
17 | #include "CodeGenFunction.h" |
18 | #include "clang/Basic/LLVM.h" |
19 | #include "clang/CodeGen/CodeGenABITypes.h" |
20 | |
21 | namespace llvm { |
22 | class Constant; |
23 | class Type; |
24 | class Value; |
25 | class CallInst; |
26 | } |
27 | |
28 | namespace clang { |
29 | class CastExpr; |
30 | class CXXConstructorDecl; |
31 | class CXXDestructorDecl; |
32 | class CXXMethodDecl; |
33 | class CXXRecordDecl; |
34 | class FieldDecl; |
35 | class MangleContext; |
36 | |
37 | namespace CodeGen { |
38 | class CGCallee; |
39 | class CodeGenFunction; |
40 | class CodeGenModule; |
41 | struct CatchTypeInfo; |
42 | |
43 | /// Implements C++ ABI-specific code generation functions. |
44 | class CGCXXABI { |
45 | protected: |
46 | CodeGenModule &CGM; |
47 | std::unique_ptr<MangleContext> MangleCtx; |
48 | |
49 | CGCXXABI(CodeGenModule &CGM) |
50 | : CGM(CGM), MangleCtx(CGM.getContext().createMangleContext()) {} |
51 | |
52 | protected: |
53 | ImplicitParamDecl *getThisDecl(CodeGenFunction &CGF) { |
54 | return CGF.CXXABIThisDecl; |
55 | } |
56 | llvm::Value *getThisValue(CodeGenFunction &CGF) { |
57 | return CGF.CXXABIThisValue; |
58 | } |
59 | Address getThisAddress(CodeGenFunction &CGF) { |
60 | return Address(CGF.CXXABIThisValue, CGF.CXXABIThisAlignment); |
61 | } |
62 | |
63 | /// Issue a diagnostic about unsupported features in the ABI. |
64 | void ErrorUnsupportedABI(CodeGenFunction &CGF, StringRef S); |
65 | |
66 | /// Get a null value for unsupported member pointers. |
67 | llvm::Constant *GetBogusMemberPointer(QualType T); |
68 | |
69 | ImplicitParamDecl *&getStructorImplicitParamDecl(CodeGenFunction &CGF) { |
70 | return CGF.CXXStructorImplicitParamDecl; |
71 | } |
72 | llvm::Value *&getStructorImplicitParamValue(CodeGenFunction &CGF) { |
73 | return CGF.CXXStructorImplicitParamValue; |
74 | } |
75 | |
76 | /// Loads the incoming C++ this pointer as it was passed by the caller. |
77 | llvm::Value *loadIncomingCXXThis(CodeGenFunction &CGF); |
78 | |
79 | void setCXXABIThisValue(CodeGenFunction &CGF, llvm::Value *ThisPtr); |
80 | |
81 | ASTContext &getContext() const { return CGM.getContext(); } |
82 | |
83 | virtual bool requiresArrayCookie(const CXXDeleteExpr *E, QualType eltType); |
84 | virtual bool requiresArrayCookie(const CXXNewExpr *E); |
85 | |
86 | /// Determine whether there's something special about the rules of |
87 | /// the ABI tell us that 'this' is a complete object within the |
88 | /// given function. Obvious common logic like being defined on a |
89 | /// final class will have been taken care of by the caller. |
90 | virtual bool isThisCompleteObject(GlobalDecl GD) const = 0; |
91 | |
92 | public: |
93 | |
94 | virtual ~CGCXXABI(); |
95 | |
96 | /// Gets the mangle context. |
97 | MangleContext &getMangleContext() { |
98 | return *MangleCtx; |
99 | } |
100 | |
101 | /// Returns true if the given constructor or destructor is one of the |
102 | /// kinds that the ABI says returns 'this' (only applies when called |
103 | /// non-virtually for destructors). |
104 | /// |
105 | /// There currently is no way to indicate if a destructor returns 'this' |
106 | /// when called virtually, and code generation does not support the case. |
107 | virtual bool HasThisReturn(GlobalDecl GD) const { return false; } |
108 | |
109 | virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; } |
110 | |
111 | virtual bool useSinitAndSterm() const { return false; } |
112 | |
113 | /// Returns true if the target allows calling a function through a pointer |
114 | /// with a different signature than the actual function (or equivalently, |
115 | /// bitcasting a function or function pointer to a different function type). |
116 | /// In principle in the most general case this could depend on the target, the |
117 | /// calling convention, and the actual types of the arguments and return |
118 | /// value. Here it just means whether the signature mismatch could *ever* be |
119 | /// allowed; in other words, does the target do strict checking of signatures |
120 | /// for all calls. |
121 | virtual bool canCallMismatchedFunctionType() const { return true; } |
122 | |
123 | /// If the C++ ABI requires the given type be returned in a particular way, |
124 | /// this method sets RetAI and returns true. |
125 | virtual bool classifyReturnType(CGFunctionInfo &FI) const = 0; |
126 | |
127 | /// Specify how one should pass an argument of a record type. |
128 | enum RecordArgABI { |
129 | /// Pass it using the normal C aggregate rules for the ABI, potentially |
130 | /// introducing extra copies and passing some or all of it in registers. |
131 | RAA_Default = 0, |
132 | |
133 | /// Pass it on the stack using its defined layout. The argument must be |
134 | /// evaluated directly into the correct stack position in the arguments area, |
135 | /// and the call machinery must not move it or introduce extra copies. |
136 | RAA_DirectInMemory, |
137 | |
138 | /// Pass it as a pointer to temporary memory. |
139 | RAA_Indirect |
140 | }; |
141 | |
142 | /// Returns how an argument of the given record type should be passed. |
143 | virtual RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const = 0; |
144 | |
145 | /// Returns true if the implicit 'sret' parameter comes after the implicit |
146 | /// 'this' parameter of C++ instance methods. |
147 | virtual bool isSRetParameterAfterThis() const { return false; } |
148 | |
149 | /// Returns true if the ABI permits the argument to be a homogeneous |
150 | /// aggregate. |
151 | virtual bool |
152 | isPermittedToBeHomogeneousAggregate(const CXXRecordDecl *RD) const { |
153 | return true; |
154 | }; |
155 | |
156 | /// Find the LLVM type used to represent the given member pointer |
157 | /// type. |
158 | virtual llvm::Type * |
159 | ConvertMemberPointerType(const MemberPointerType *MPT); |
160 | |
161 | /// Load a member function from an object and a member function |
162 | /// pointer. Apply the this-adjustment and set 'This' to the |
163 | /// adjusted value. |
164 | virtual CGCallee EmitLoadOfMemberFunctionPointer( |
165 | CodeGenFunction &CGF, const Expr *E, Address This, |
166 | llvm::Value *&ThisPtrForCall, llvm::Value *MemPtr, |
167 | const MemberPointerType *MPT); |
168 | |
169 | /// Calculate an l-value from an object and a data member pointer. |
170 | virtual llvm::Value * |
171 | EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E, |
172 | Address Base, llvm::Value *MemPtr, |
173 | const MemberPointerType *MPT); |
174 | |
175 | /// Perform a derived-to-base, base-to-derived, or bitcast member |
176 | /// pointer conversion. |
177 | virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, |
178 | const CastExpr *E, |
179 | llvm::Value *Src); |
180 | |
181 | /// Perform a derived-to-base, base-to-derived, or bitcast member |
182 | /// pointer conversion on a constant value. |
183 | virtual llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, |
184 | llvm::Constant *Src); |
185 | |
186 | /// Return true if the given member pointer can be zero-initialized |
187 | /// (in the C++ sense) with an LLVM zeroinitializer. |
188 | virtual bool isZeroInitializable(const MemberPointerType *MPT); |
189 | |
190 | /// Return whether or not a member pointers type is convertible to an IR type. |
191 | virtual bool isMemberPointerConvertible(const MemberPointerType *MPT) const { |
192 | return true; |
193 | } |
194 | |
195 | /// Create a null member pointer of the given type. |
196 | virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT); |
197 | |
198 | /// Create a member pointer for the given method. |
199 | virtual llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD); |
200 | |
201 | /// Create a member pointer for the given field. |
202 | virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, |
203 | CharUnits offset); |
204 | |
205 | /// Create a member pointer for the given member pointer constant. |
206 | virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT); |
207 | |
208 | /// Emit a comparison between two member pointers. Returns an i1. |
209 | virtual llvm::Value * |
210 | EmitMemberPointerComparison(CodeGenFunction &CGF, |
211 | llvm::Value *L, |
212 | llvm::Value *R, |
213 | const MemberPointerType *MPT, |
214 | bool Inequality); |
215 | |
216 | /// Determine if a member pointer is non-null. Returns an i1. |
217 | virtual llvm::Value * |
218 | EmitMemberPointerIsNotNull(CodeGenFunction &CGF, |
219 | llvm::Value *MemPtr, |
220 | const MemberPointerType *MPT); |
221 | |
222 | protected: |
223 | /// A utility method for computing the offset required for the given |
224 | /// base-to-derived or derived-to-base member-pointer conversion. |
225 | /// Does not handle virtual conversions (in case we ever fully |
226 | /// support an ABI that allows this). Returns null if no adjustment |
227 | /// is required. |
228 | llvm::Constant *getMemberPointerAdjustment(const CastExpr *E); |
229 | |
230 | public: |
231 | virtual void emitVirtualObjectDelete(CodeGenFunction &CGF, |
232 | const CXXDeleteExpr *DE, |
233 | Address Ptr, QualType ElementType, |
234 | const CXXDestructorDecl *Dtor) = 0; |
235 | virtual void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) = 0; |
236 | virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0; |
237 | virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; } |
238 | |
239 | /// Determine whether it's possible to emit a vtable for \p RD, even |
240 | /// though we do not know that the vtable has been marked as used by semantic |
241 | /// analysis. |
242 | virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const = 0; |
243 | |
244 | virtual void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) = 0; |
245 | |
246 | virtual llvm::CallInst * |
247 | emitTerminateForUnexpectedException(CodeGenFunction &CGF, |
248 | llvm::Value *Exn); |
249 | |
250 | virtual llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) = 0; |
251 | virtual CatchTypeInfo |
252 | getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) = 0; |
253 | virtual CatchTypeInfo getCatchAllTypeInfo(); |
254 | |
255 | virtual bool shouldTypeidBeNullChecked(bool IsDeref, |
256 | QualType SrcRecordTy) = 0; |
257 | virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0; |
258 | virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy, |
259 | Address ThisPtr, |
260 | llvm::Type *StdTypeInfoPtrTy) = 0; |
261 | |
262 | virtual bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, |
263 | QualType SrcRecordTy) = 0; |
264 | |
265 | virtual llvm::Value * |
266 | EmitDynamicCastCall(CodeGenFunction &CGF, Address Value, |
267 | QualType SrcRecordTy, QualType DestTy, |
268 | QualType DestRecordTy, llvm::BasicBlock *CastEnd) = 0; |
269 | |
270 | virtual llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, |
271 | Address Value, |
272 | QualType SrcRecordTy, |
273 | QualType DestTy) = 0; |
274 | |
275 | virtual bool EmitBadCastCall(CodeGenFunction &CGF) = 0; |
276 | |
277 | virtual llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF, |
278 | Address This, |
279 | const CXXRecordDecl *ClassDecl, |
280 | const CXXRecordDecl *BaseClassDecl) = 0; |
281 | |
282 | virtual llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF, |
283 | const CXXRecordDecl *RD); |
284 | |
285 | /// Emit the code to initialize hidden members required |
286 | /// to handle virtual inheritance, if needed by the ABI. |
287 | virtual void |
288 | initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF, |
289 | const CXXRecordDecl *RD) {} |
290 | |
291 | /// Emit constructor variants required by this ABI. |
292 | virtual void EmitCXXConstructors(const CXXConstructorDecl *D) = 0; |
293 | |
294 | /// Additional implicit arguments to add to the beginning (Prefix) and end |
295 | /// (Suffix) of a constructor / destructor arg list. |
296 | /// |
297 | /// Note that Prefix should actually be inserted *after* the first existing |
298 | /// arg; `this` arguments always come first. |
299 | struct AddedStructorArgs { |
300 | struct Arg { |
301 | llvm::Value *Value; |
302 | QualType Type; |
303 | }; |
304 | SmallVector<Arg, 1> Prefix; |
305 | SmallVector<Arg, 1> Suffix; |
306 | AddedStructorArgs() = default; |
307 | AddedStructorArgs(SmallVector<Arg, 1> P, SmallVector<Arg, 1> S) |
308 | : Prefix(std::move(P)), Suffix(std::move(S)) {} |
309 | static AddedStructorArgs prefix(SmallVector<Arg, 1> Args) { |
310 | return {std::move(Args), {}}; |
311 | } |
312 | static AddedStructorArgs suffix(SmallVector<Arg, 1> Args) { |
313 | return {{}, std::move(Args)}; |
314 | } |
315 | }; |
316 | |
317 | /// Similar to AddedStructorArgs, but only notes the number of additional |
318 | /// arguments. |
319 | struct AddedStructorArgCounts { |
320 | unsigned Prefix = 0; |
321 | unsigned Suffix = 0; |
322 | AddedStructorArgCounts() = default; |
323 | AddedStructorArgCounts(unsigned P, unsigned S) : Prefix(P), Suffix(S) {} |
324 | static AddedStructorArgCounts prefix(unsigned N) { return {N, 0}; } |
325 | static AddedStructorArgCounts suffix(unsigned N) { return {0, N}; } |
326 | }; |
327 | |
328 | /// Build the signature of the given constructor or destructor variant by |
329 | /// adding any required parameters. For convenience, ArgTys has been |
330 | /// initialized with the type of 'this'. |
331 | virtual AddedStructorArgCounts |
332 | buildStructorSignature(GlobalDecl GD, |
333 | SmallVectorImpl<CanQualType> &ArgTys) = 0; |
334 | |
335 | /// Returns true if the given destructor type should be emitted as a linkonce |
336 | /// delegating thunk, regardless of whether the dtor is defined in this TU or |
337 | /// not. |
338 | virtual bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, |
339 | CXXDtorType DT) const = 0; |
340 | |
341 | virtual void setCXXDestructorDLLStorage(llvm::GlobalValue *GV, |
342 | const CXXDestructorDecl *Dtor, |
343 | CXXDtorType DT) const; |
344 | |
345 | virtual llvm::GlobalValue::LinkageTypes |
346 | getCXXDestructorLinkage(GVALinkage Linkage, const CXXDestructorDecl *Dtor, |
347 | CXXDtorType DT) const; |
348 | |
349 | /// Emit destructor variants required by this ABI. |
350 | virtual void EmitCXXDestructors(const CXXDestructorDecl *D) = 0; |
351 | |
352 | /// Get the type of the implicit "this" parameter used by a method. May return |
353 | /// zero if no specific type is applicable, e.g. if the ABI expects the "this" |
354 | /// parameter to point to some artificial offset in a complete object due to |
355 | /// vbases being reordered. |
356 | virtual const CXXRecordDecl * |
357 | getThisArgumentTypeForMethod(const CXXMethodDecl *MD) { |
358 | return MD->getParent(); |
359 | } |
360 | |
361 | /// Perform ABI-specific "this" argument adjustment required prior to |
362 | /// a call of a virtual function. |
363 | /// The "VirtualCall" argument is true iff the call itself is virtual. |
364 | virtual Address |
365 | adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD, |
366 | Address This, bool VirtualCall) { |
367 | return This; |
368 | } |
369 | |
370 | /// Build a parameter variable suitable for 'this'. |
371 | void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params); |
372 | |
373 | /// Insert any ABI-specific implicit parameters into the parameter list for a |
374 | /// function. This generally involves extra data for constructors and |
375 | /// destructors. |
376 | /// |
377 | /// ABIs may also choose to override the return type, which has been |
378 | /// initialized with the type of 'this' if HasThisReturn(CGF.CurGD) is true or |
379 | /// the formal return type of the function otherwise. |
380 | virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy, |
381 | FunctionArgList &Params) = 0; |
382 | |
383 | /// Get the ABI-specific "this" parameter adjustment to apply in the prologue |
384 | /// of a virtual function. |
385 | virtual CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) { |
386 | return CharUnits::Zero(); |
387 | } |
388 | |
389 | /// Emit the ABI-specific prolog for the function. |
390 | virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0; |
391 | |
392 | virtual AddedStructorArgs |
393 | getImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D, |
394 | CXXCtorType Type, bool ForVirtualBase, |
395 | bool Delegating) = 0; |
396 | |
397 | /// Add any ABI-specific implicit arguments needed to call a constructor. |
398 | /// |
399 | /// \return The number of arguments added at the beginning and end of the |
400 | /// call, which is typically zero or one. |
401 | AddedStructorArgCounts |
402 | addImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D, |
403 | CXXCtorType Type, bool ForVirtualBase, |
404 | bool Delegating, CallArgList &Args); |
405 | |
406 | /// Get the implicit (second) parameter that comes after the "this" pointer, |
407 | /// or nullptr if there is isn't one. |
408 | virtual llvm::Value * |
409 | getCXXDestructorImplicitParam(CodeGenFunction &CGF, |
410 | const CXXDestructorDecl *DD, CXXDtorType Type, |
411 | bool ForVirtualBase, bool Delegating) = 0; |
412 | |
413 | /// Emit the destructor call. |
414 | virtual void EmitDestructorCall(CodeGenFunction &CGF, |
415 | const CXXDestructorDecl *DD, CXXDtorType Type, |
416 | bool ForVirtualBase, bool Delegating, |
417 | Address This, QualType ThisTy) = 0; |
418 | |
419 | /// Emits the VTable definitions required for the given record type. |
420 | virtual void emitVTableDefinitions(CodeGenVTables &CGVT, |
421 | const CXXRecordDecl *RD) = 0; |
422 | |
423 | /// Checks if ABI requires extra virtual offset for vtable field. |
424 | virtual bool |
425 | isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF, |
426 | CodeGenFunction::VPtr Vptr) = 0; |
427 | |
428 | /// Checks if ABI requires to initialize vptrs for given dynamic class. |
429 | virtual bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) = 0; |
430 | |
431 | /// Get the address point of the vtable for the given base subobject. |
432 | virtual llvm::Constant * |
433 | getVTableAddressPoint(BaseSubobject Base, |
434 | const CXXRecordDecl *VTableClass) = 0; |
435 | |
436 | /// Get the address point of the vtable for the given base subobject while |
437 | /// building a constructor or a destructor. |
438 | virtual llvm::Value * |
439 | getVTableAddressPointInStructor(CodeGenFunction &CGF, const CXXRecordDecl *RD, |
440 | BaseSubobject Base, |
441 | const CXXRecordDecl *NearestVBase) = 0; |
442 | |
443 | /// Get the address point of the vtable for the given base subobject while |
444 | /// building a constexpr. |
445 | virtual llvm::Constant * |
446 | getVTableAddressPointForConstExpr(BaseSubobject Base, |
447 | const CXXRecordDecl *VTableClass) = 0; |
448 | |
449 | /// Get the address of the vtable for the given record decl which should be |
450 | /// used for the vptr at the given offset in RD. |
451 | virtual llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, |
452 | CharUnits VPtrOffset) = 0; |
453 | |
454 | /// Build a virtual function pointer in the ABI-specific way. |
455 | virtual CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF, |
456 | GlobalDecl GD, Address This, |
457 | llvm::Type *Ty, |
458 | SourceLocation Loc) = 0; |
459 | |
460 | using DeleteOrMemberCallExpr = |
461 | llvm::PointerUnion<const CXXDeleteExpr *, const CXXMemberCallExpr *>; |
462 | |
463 | /// Emit the ABI-specific virtual destructor call. |
464 | virtual llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF, |
465 | const CXXDestructorDecl *Dtor, |
466 | CXXDtorType DtorType, |
467 | Address This, |
468 | DeleteOrMemberCallExpr E) = 0; |
469 | |
470 | virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, |
471 | GlobalDecl GD, |
472 | CallArgList &CallArgs) {} |
473 | |
474 | /// Emit any tables needed to implement virtual inheritance. For Itanium, |
475 | /// this emits virtual table tables. For the MSVC++ ABI, this emits virtual |
476 | /// base tables. |
477 | virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD) = 0; |
478 | |
479 | virtual bool exportThunk() = 0; |
480 | virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, |
481 | GlobalDecl GD, bool ReturnAdjustment) = 0; |
482 | |
483 | virtual llvm::Value *performThisAdjustment(CodeGenFunction &CGF, |
484 | Address This, |
485 | const ThisAdjustment &TA) = 0; |
486 | |
487 | virtual llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, |
488 | Address Ret, |
489 | const ReturnAdjustment &RA) = 0; |
490 | |
491 | virtual void EmitReturnFromThunk(CodeGenFunction &CGF, |
492 | RValue RV, QualType ResultType); |
493 | |
494 | virtual size_t getSrcArgforCopyCtor(const CXXConstructorDecl *, |
495 | FunctionArgList &Args) const = 0; |
496 | |
497 | /// Gets the offsets of all the virtual base pointers in a given class. |
498 | virtual std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD); |
499 | |
500 | /// Gets the pure virtual member call function. |
501 | virtual StringRef GetPureVirtualCallName() = 0; |
502 | |
503 | /// Gets the deleted virtual member call name. |
504 | virtual StringRef GetDeletedVirtualCallName() = 0; |
505 | |
506 | /**************************** Array cookies ******************************/ |
507 | |
508 | /// Returns the extra size required in order to store the array |
509 | /// cookie for the given new-expression. May return 0 to indicate that no |
510 | /// array cookie is required. |
511 | /// |
512 | /// Several cases are filtered out before this method is called: |
513 | /// - non-array allocations never need a cookie |
514 | /// - calls to \::operator new(size_t, void*) never need a cookie |
515 | /// |
516 | /// \param expr - the new-expression being allocated. |
517 | virtual CharUnits GetArrayCookieSize(const CXXNewExpr *expr); |
518 | |
519 | /// Initialize the array cookie for the given allocation. |
520 | /// |
521 | /// \param NewPtr - a char* which is the presumed-non-null |
522 | /// return value of the allocation function |
523 | /// \param NumElements - the computed number of elements, |
524 | /// potentially collapsed from the multidimensional array case; |
525 | /// always a size_t |
526 | /// \param ElementType - the base element allocated type, |
527 | /// i.e. the allocated type after stripping all array types |
528 | virtual Address InitializeArrayCookie(CodeGenFunction &CGF, |
529 | Address NewPtr, |
530 | llvm::Value *NumElements, |
531 | const CXXNewExpr *expr, |
532 | QualType ElementType); |
533 | |
534 | /// Reads the array cookie associated with the given pointer, |
535 | /// if it has one. |
536 | /// |
537 | /// \param Ptr - a pointer to the first element in the array |
538 | /// \param ElementType - the base element type of elements of the array |
539 | /// \param NumElements - an out parameter which will be initialized |
540 | /// with the number of elements allocated, or zero if there is no |
541 | /// cookie |
542 | /// \param AllocPtr - an out parameter which will be initialized |
543 | /// with a char* pointing to the address returned by the allocation |
544 | /// function |
545 | /// \param CookieSize - an out parameter which will be initialized |
546 | /// with the size of the cookie, or zero if there is no cookie |
547 | virtual void ReadArrayCookie(CodeGenFunction &CGF, Address Ptr, |
548 | const CXXDeleteExpr *expr, |
549 | QualType ElementType, llvm::Value *&NumElements, |
550 | llvm::Value *&AllocPtr, CharUnits &CookieSize); |
551 | |
552 | /// Return whether the given global decl needs a VTT parameter. |
553 | virtual bool NeedsVTTParameter(GlobalDecl GD); |
554 | |
555 | protected: |
556 | /// Returns the extra size required in order to store the array |
557 | /// cookie for the given type. Assumes that an array cookie is |
558 | /// required. |
559 | virtual CharUnits getArrayCookieSizeImpl(QualType elementType); |
560 | |
561 | /// Reads the array cookie for an allocation which is known to have one. |
562 | /// This is called by the standard implementation of ReadArrayCookie. |
563 | /// |
564 | /// \param ptr - a pointer to the allocation made for an array, as a char* |
565 | /// \param cookieSize - the computed cookie size of an array |
566 | /// |
567 | /// Other parameters are as above. |
568 | /// |
569 | /// \return a size_t |
570 | virtual llvm::Value *readArrayCookieImpl(CodeGenFunction &IGF, Address ptr, |
571 | CharUnits cookieSize); |
572 | |
573 | public: |
574 | |
575 | /*************************** Static local guards ****************************/ |
576 | |
577 | /// Emits the guarded initializer and destructor setup for the given |
578 | /// variable, given that it couldn't be emitted as a constant. |
579 | /// If \p PerformInit is false, the initialization has been folded to a |
580 | /// constant and should not be performed. |
581 | /// |
582 | /// The variable may be: |
583 | /// - a static local variable |
584 | /// - a static data member of a class template instantiation |
585 | virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, |
586 | llvm::GlobalVariable *DeclPtr, |
587 | bool PerformInit) = 0; |
588 | |
589 | /// Emit code to force the execution of a destructor during global |
590 | /// teardown. The default implementation of this uses atexit. |
591 | /// |
592 | /// \param Dtor - a function taking a single pointer argument |
593 | /// \param Addr - a pointer to pass to the destructor function. |
594 | virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, |
595 | llvm::FunctionCallee Dtor, |
596 | llvm::Constant *Addr) = 0; |
597 | |
598 | /*************************** thread_local initialization ********************/ |
599 | |
600 | /// Emits ABI-required functions necessary to initialize thread_local |
601 | /// variables in this translation unit. |
602 | /// |
603 | /// \param CXXThreadLocals - The thread_local declarations in this translation |
604 | /// unit. |
605 | /// \param CXXThreadLocalInits - If this translation unit contains any |
606 | /// non-constant initialization or non-trivial destruction for |
607 | /// thread_local variables, a list of functions to perform the |
608 | /// initialization. |
609 | virtual void EmitThreadLocalInitFuncs( |
610 | CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals, |
611 | ArrayRef<llvm::Function *> CXXThreadLocalInits, |
612 | ArrayRef<const VarDecl *> CXXThreadLocalInitVars) = 0; |
613 | |
614 | // Determine if references to thread_local global variables can be made |
615 | // directly or require access through a thread wrapper function. |
616 | virtual bool usesThreadWrapperFunction(const VarDecl *VD) const = 0; |
617 | |
618 | /// Emit a reference to a non-local thread_local variable (including |
619 | /// triggering the initialization of all thread_local variables in its |
620 | /// translation unit). |
621 | virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, |
622 | const VarDecl *VD, |
623 | QualType LValType) = 0; |
624 | |
625 | /// Emit a single constructor/destructor with the given type from a C++ |
626 | /// constructor Decl. |
627 | virtual void emitCXXStructor(GlobalDecl GD) = 0; |
628 | |
629 | /// Load a vtable from This, an object of polymorphic type RD, or from one of |
630 | /// its virtual bases if it does not have its own vtable. Returns the vtable |
631 | /// and the class from which the vtable was loaded. |
632 | virtual std::pair<llvm::Value *, const CXXRecordDecl *> |
633 | LoadVTablePtr(CodeGenFunction &CGF, Address This, |
634 | const CXXRecordDecl *RD) = 0; |
635 | }; |
636 | |
637 | // Create an instance of a C++ ABI class: |
638 | |
639 | /// Creates an Itanium-family ABI. |
640 | CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM); |
641 | |
642 | /// Creates a Microsoft-family ABI. |
643 | CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM); |
644 | |
645 | struct CatchRetScope final : EHScopeStack::Cleanup { |
646 | llvm::CatchPadInst *CPI; |
647 | |
648 | CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {} |
649 | |
650 | void Emit(CodeGenFunction &CGF, Flags flags) override { |
651 | llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest" ); |
652 | CGF.Builder.CreateCatchRet(CPI, BB); |
653 | CGF.EmitBlock(BB); |
654 | } |
655 | }; |
656 | } |
657 | } |
658 | |
659 | #endif |
660 | |