Coverage Report

Created: 2022-01-18 06:27

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/CodeGen/CGCXXABI.h
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//===----- CGCXXABI.h - Interface to C++ ABIs -------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4
// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This provides an abstract class for C++ code generation. Concrete subclasses
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// of this implement code generation for specific C++ ABIs.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_LIB_CODEGEN_CGCXXABI_H
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#define LLVM_CLANG_LIB_CODEGEN_CGCXXABI_H
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17
#include "CodeGenFunction.h"
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#include "clang/Basic/LLVM.h"
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#include "clang/CodeGen/CodeGenABITypes.h"
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21
namespace llvm {
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class Constant;
23
class Type;
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class Value;
25
class CallInst;
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}
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28
namespace clang {
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class CastExpr;
30
class CXXConstructorDecl;
31
class CXXDestructorDecl;
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class CXXMethodDecl;
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class CXXRecordDecl;
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class MangleContext;
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36
namespace CodeGen {
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class CGCallee;
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class CodeGenFunction;
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class CodeGenModule;
40
struct CatchTypeInfo;
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/// Implements C++ ABI-specific code generation functions.
43
class CGCXXABI {
44
protected:
45
  CodeGenModule &CGM;
46
  std::unique_ptr<MangleContext> MangleCtx;
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48
  CGCXXABI(CodeGenModule &CGM)
49
35.0k
    : CGM(CGM), MangleCtx(CGM.getContext().createMangleContext()) {}
50
51
protected:
52
211k
  ImplicitParamDecl *getThisDecl(CodeGenFunction &CGF) {
53
211k
    return CGF.CXXABIThisDecl;
54
211k
  }
55
2.13k
  llvm::Value *getThisValue(CodeGenFunction &CGF) {
56
2.13k
    return CGF.CXXABIThisValue;
57
2.13k
  }
58
903
  Address getThisAddress(CodeGenFunction &CGF) {
59
903
    return Address(CGF.CXXABIThisValue, CGF.CXXABIThisAlignment);
60
903
  }
61
62
  /// Issue a diagnostic about unsupported features in the ABI.
63
  void ErrorUnsupportedABI(CodeGenFunction &CGF, StringRef S);
64
65
  /// Get a null value for unsupported member pointers.
66
  llvm::Constant *GetBogusMemberPointer(QualType T);
67
68
104k
  ImplicitParamDecl *&getStructorImplicitParamDecl(CodeGenFunction &CGF) {
69
104k
    return CGF.CXXStructorImplicitParamDecl;
70
104k
  }
71
1.43k
  llvm::Value *&getStructorImplicitParamValue(CodeGenFunction &CGF) {
72
1.43k
    return CGF.CXXStructorImplicitParamValue;
73
1.43k
  }
74
75
  /// Loads the incoming C++ this pointer as it was passed by the caller.
76
  llvm::Value *loadIncomingCXXThis(CodeGenFunction &CGF);
77
78
  void setCXXABIThisValue(CodeGenFunction &CGF, llvm::Value *ThisPtr);
79
80
402k
  ASTContext &getContext() const { return CGM.getContext(); }
81
82
  bool mayNeedDestruction(const VarDecl *VD) const;
83
84
  /// Determine whether we will definitely emit this variable with a constant
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  /// initializer, either because the language semantics demand it or because
86
  /// we know that the initializer is a constant.
87
  // For weak definitions, any initializer available in the current translation
88
  // is not necessarily reflective of the initializer used; such initializers
89
  // are ignored unless if InspectInitForWeakDef is true.
90
  bool
91
  isEmittedWithConstantInitializer(const VarDecl *VD,
92
                                   bool InspectInitForWeakDef = false) const;
93
94
  virtual bool requiresArrayCookie(const CXXDeleteExpr *E, QualType eltType);
95
  virtual bool requiresArrayCookie(const CXXNewExpr *E);
96
97
  /// Determine whether there's something special about the rules of
98
  /// the ABI tell us that 'this' is a complete object within the
99
  /// given function.  Obvious common logic like being defined on a
100
  /// final class will have been taken care of by the caller.
101
  virtual bool isThisCompleteObject(GlobalDecl GD) const = 0;
102
103
public:
104
105
  virtual ~CGCXXABI();
106
107
  /// Gets the mangle context.
108
3.41M
  MangleContext &getMangleContext() {
109
3.41M
    return *MangleCtx;
110
3.41M
  }
111
112
  /// Returns true if the given constructor or destructor is one of the
113
  /// kinds that the ABI says returns 'this' (only applies when called
114
  /// non-virtually for destructors).
115
  ///
116
  /// There currently is no way to indicate if a destructor returns 'this'
117
  /// when called virtually, and code generation does not support the case.
118
821k
  virtual bool HasThisReturn(GlobalDecl GD) const { return false; }
119
120
442k
  virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; }
121
122
35.8k
  virtual bool useSinitAndSterm() const { return false; }
123
124
  /// Returns true if the target allows calling a function through a pointer
125
  /// with a different signature than the actual function (or equivalently,
126
  /// bitcasting a function or function pointer to a different function type).
127
  /// In principle in the most general case this could depend on the target, the
128
  /// calling convention, and the actual types of the arguments and return
129
  /// value. Here it just means whether the signature mismatch could *ever* be
130
  /// allowed; in other words, does the target do strict checking of signatures
131
  /// for all calls.
132
7
  virtual bool canCallMismatchedFunctionType() const { return true; }
133
134
  /// If the C++ ABI requires the given type be returned in a particular way,
135
  /// this method sets RetAI and returns true.
136
  virtual bool classifyReturnType(CGFunctionInfo &FI) const = 0;
137
138
  /// Specify how one should pass an argument of a record type.
139
  enum RecordArgABI {
140
    /// Pass it using the normal C aggregate rules for the ABI, potentially
141
    /// introducing extra copies and passing some or all of it in registers.
142
    RAA_Default = 0,
143
144
    /// Pass it on the stack using its defined layout.  The argument must be
145
    /// evaluated directly into the correct stack position in the arguments area,
146
    /// and the call machinery must not move it or introduce extra copies.
147
    RAA_DirectInMemory,
148
149
    /// Pass it as a pointer to temporary memory.
150
    RAA_Indirect
151
  };
152
153
  /// Returns how an argument of the given record type should be passed.
154
  virtual RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const = 0;
155
156
  /// Returns true if the implicit 'sret' parameter comes after the implicit
157
  /// 'this' parameter of C++ instance methods.
158
0
  virtual bool isSRetParameterAfterThis() const { return false; }
159
160
  /// Returns true if the ABI permits the argument to be a homogeneous
161
  /// aggregate.
162
  virtual bool
163
429
  isPermittedToBeHomogeneousAggregate(const CXXRecordDecl *RD) const {
164
429
    return true;
165
429
  };
166
167
  /// Find the LLVM type used to represent the given member pointer
168
  /// type.
169
  virtual llvm::Type *
170
  ConvertMemberPointerType(const MemberPointerType *MPT);
171
172
  /// Load a member function from an object and a member function
173
  /// pointer.  Apply the this-adjustment and set 'This' to the
174
  /// adjusted value.
175
  virtual CGCallee EmitLoadOfMemberFunctionPointer(
176
      CodeGenFunction &CGF, const Expr *E, Address This,
177
      llvm::Value *&ThisPtrForCall, llvm::Value *MemPtr,
178
      const MemberPointerType *MPT);
179
180
  /// Calculate an l-value from an object and a data member pointer.
181
  virtual llvm::Value *
182
  EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
183
                               Address Base, llvm::Value *MemPtr,
184
                               const MemberPointerType *MPT);
185
186
  /// Perform a derived-to-base, base-to-derived, or bitcast member
187
  /// pointer conversion.
188
  virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
189
                                                   const CastExpr *E,
190
                                                   llvm::Value *Src);
191
192
  /// Perform a derived-to-base, base-to-derived, or bitcast member
193
  /// pointer conversion on a constant value.
194
  virtual llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
195
                                                      llvm::Constant *Src);
196
197
  /// Return true if the given member pointer can be zero-initialized
198
  /// (in the C++ sense) with an LLVM zeroinitializer.
199
  virtual bool isZeroInitializable(const MemberPointerType *MPT);
200
201
  /// Return whether or not a member pointers type is convertible to an IR type.
202
480
  virtual bool isMemberPointerConvertible(const MemberPointerType *MPT) const {
203
480
    return true;
204
480
  }
205
206
  /// Create a null member pointer of the given type.
207
  virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT);
208
209
  /// Create a member pointer for the given method.
210
  virtual llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD);
211
212
  /// Create a member pointer for the given field.
213
  virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
214
                                                CharUnits offset);
215
216
  /// Create a member pointer for the given member pointer constant.
217
  virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT);
218
219
  /// Emit a comparison between two member pointers.  Returns an i1.
220
  virtual llvm::Value *
221
  EmitMemberPointerComparison(CodeGenFunction &CGF,
222
                              llvm::Value *L,
223
                              llvm::Value *R,
224
                              const MemberPointerType *MPT,
225
                              bool Inequality);
226
227
  /// Determine if a member pointer is non-null.  Returns an i1.
228
  virtual llvm::Value *
229
  EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
230
                             llvm::Value *MemPtr,
231
                             const MemberPointerType *MPT);
232
233
protected:
234
  /// A utility method for computing the offset required for the given
235
  /// base-to-derived or derived-to-base member-pointer conversion.
236
  /// Does not handle virtual conversions (in case we ever fully
237
  /// support an ABI that allows this).  Returns null if no adjustment
238
  /// is required.
239
  llvm::Constant *getMemberPointerAdjustment(const CastExpr *E);
240
241
public:
242
  virtual void emitVirtualObjectDelete(CodeGenFunction &CGF,
243
                                       const CXXDeleteExpr *DE,
244
                                       Address Ptr, QualType ElementType,
245
                                       const CXXDestructorDecl *Dtor) = 0;
246
  virtual void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) = 0;
247
  virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0;
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0
  virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; }
249
250
  /// Determine whether it's possible to emit a vtable for \p RD, even
251
  /// though we do not know that the vtable has been marked as used by semantic
252
  /// analysis.
253
  virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const = 0;
254
255
  virtual void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) = 0;
256
257
  virtual llvm::CallInst *
258
  emitTerminateForUnexpectedException(CodeGenFunction &CGF,
259
                                      llvm::Value *Exn);
260
261
  virtual llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) = 0;
262
  virtual CatchTypeInfo
263
  getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) = 0;
264
  virtual CatchTypeInfo getCatchAllTypeInfo();
265
266
  virtual bool shouldTypeidBeNullChecked(bool IsDeref,
267
                                         QualType SrcRecordTy) = 0;
268
  virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0;
269
  virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
270
                                  Address ThisPtr,
271
                                  llvm::Type *StdTypeInfoPtrTy) = 0;
272
273
  virtual bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
274
                                                  QualType SrcRecordTy) = 0;
275
276
  virtual llvm::Value *
277
  EmitDynamicCastCall(CodeGenFunction &CGF, Address Value,
278
                      QualType SrcRecordTy, QualType DestTy,
279
                      QualType DestRecordTy, llvm::BasicBlock *CastEnd) = 0;
280
281
  virtual llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF,
282
                                             Address Value,
283
                                             QualType SrcRecordTy,
284
                                             QualType DestTy) = 0;
285
286
  virtual bool EmitBadCastCall(CodeGenFunction &CGF) = 0;
287
288
  virtual llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF,
289
                                                 Address This,
290
                                                 const CXXRecordDecl *ClassDecl,
291
                                        const CXXRecordDecl *BaseClassDecl) = 0;
292
293
  virtual llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
294
                                                          const CXXRecordDecl *RD);
295
296
  /// Emit the code to initialize hidden members required
297
  /// to handle virtual inheritance, if needed by the ABI.
298
  virtual void
299
  initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
300
410
                                            const CXXRecordDecl *RD) {}
301
302
  /// Emit constructor variants required by this ABI.
303
  virtual void EmitCXXConstructors(const CXXConstructorDecl *D) = 0;
304
305
  /// Additional implicit arguments to add to the beginning (Prefix) and end
306
  /// (Suffix) of a constructor / destructor arg list.
307
  ///
308
  /// Note that Prefix should actually be inserted *after* the first existing
309
  /// arg; `this` arguments always come first.
310
  struct AddedStructorArgs {
311
    struct Arg {
312
      llvm::Value *Value;
313
      QualType Type;
314
    };
315
    SmallVector<Arg, 1> Prefix;
316
    SmallVector<Arg, 1> Suffix;
317
54.5k
    AddedStructorArgs() = default;
318
    AddedStructorArgs(SmallVector<Arg, 1> P, SmallVector<Arg, 1> S)
319
608
        : Prefix(std::move(P)), Suffix(std::move(S)) {}
320
136
    static AddedStructorArgs prefix(SmallVector<Arg, 1> Args) {
321
136
      return {std::move(Args), {}};
322
136
    }
323
472
    static AddedStructorArgs suffix(SmallVector<Arg, 1> Args) {
324
472
      return {{}, std::move(Args)};
325
472
    }
326
  };
327
328
  /// Similar to AddedStructorArgs, but only notes the number of additional
329
  /// arguments.
330
  struct AddedStructorArgCounts {
331
    unsigned Prefix = 0;
332
    unsigned Suffix = 0;
333
299k
    AddedStructorArgCounts() = default;
334
56.3k
    AddedStructorArgCounts(unsigned P, unsigned S) : Prefix(P), Suffix(S) {}
335
1.10k
    static AddedStructorArgCounts prefix(unsigned N) { return {N, 0}; }
336
0
    static AddedStructorArgCounts suffix(unsigned N) { return {0, N}; }
337
  };
338
339
  /// Build the signature of the given constructor or destructor variant by
340
  /// adding any required parameters.  For convenience, ArgTys has been
341
  /// initialized with the type of 'this'.
342
  virtual AddedStructorArgCounts
343
  buildStructorSignature(GlobalDecl GD,
344
                         SmallVectorImpl<CanQualType> &ArgTys) = 0;
345
346
  /// Returns true if the given destructor type should be emitted as a linkonce
347
  /// delegating thunk, regardless of whether the dtor is defined in this TU or
348
  /// not.
349
  virtual bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
350
                                      CXXDtorType DT) const = 0;
351
352
  virtual void setCXXDestructorDLLStorage(llvm::GlobalValue *GV,
353
                                          const CXXDestructorDecl *Dtor,
354
                                          CXXDtorType DT) const;
355
356
  virtual llvm::GlobalValue::LinkageTypes
357
  getCXXDestructorLinkage(GVALinkage Linkage, const CXXDestructorDecl *Dtor,
358
                          CXXDtorType DT) const;
359
360
  /// Emit destructor variants required by this ABI.
361
  virtual void EmitCXXDestructors(const CXXDestructorDecl *D) = 0;
362
363
  /// Get the type of the implicit "this" parameter used by a method. May return
364
  /// zero if no specific type is applicable, e.g. if the ABI expects the "this"
365
  /// parameter to point to some artificial offset in a complete object due to
366
  /// vbases being reordered.
367
  virtual const CXXRecordDecl *
368
325k
  getThisArgumentTypeForMethod(const CXXMethodDecl *MD) {
369
325k
    return MD->getParent();
370
325k
  }
371
372
  /// Perform ABI-specific "this" argument adjustment required prior to
373
  /// a call of a virtual function.
374
  /// The "VirtualCall" argument is true iff the call itself is virtual.
375
  virtual Address
376
  adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
377
1.17k
                                           Address This, bool VirtualCall) {
378
1.17k
    return This;
379
1.17k
  }
380
381
  /// Build a parameter variable suitable for 'this'.
382
  void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params);
383
384
  /// Insert any ABI-specific implicit parameters into the parameter list for a
385
  /// function.  This generally involves extra data for constructors and
386
  /// destructors.
387
  ///
388
  /// ABIs may also choose to override the return type, which has been
389
  /// initialized with the type of 'this' if HasThisReturn(CGF.CurGD) is true or
390
  /// the formal return type of the function otherwise.
391
  virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
392
                                         FunctionArgList &Params) = 0;
393
394
  /// Get the ABI-specific "this" parameter adjustment to apply in the prologue
395
  /// of a virtual function.
396
0
  virtual CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
397
0
    return CharUnits::Zero();
398
0
  }
399
400
  /// Emit the ABI-specific prolog for the function.
401
  virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0;
402
403
  virtual AddedStructorArgs
404
  getImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D,
405
                             CXXCtorType Type, bool ForVirtualBase,
406
                             bool Delegating) = 0;
407
408
  /// Add any ABI-specific implicit arguments needed to call a constructor.
409
  ///
410
  /// \return The number of arguments added at the beginning and end of the
411
  /// call, which is typically zero or one.
412
  AddedStructorArgCounts
413
  addImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D,
414
                             CXXCtorType Type, bool ForVirtualBase,
415
                             bool Delegating, CallArgList &Args);
416
417
  /// Get the implicit (second) parameter that comes after the "this" pointer,
418
  /// or nullptr if there is isn't one.
419
  virtual llvm::Value *
420
  getCXXDestructorImplicitParam(CodeGenFunction &CGF,
421
                                const CXXDestructorDecl *DD, CXXDtorType Type,
422
                                bool ForVirtualBase, bool Delegating) = 0;
423
424
  /// Emit the destructor call.
425
  virtual void EmitDestructorCall(CodeGenFunction &CGF,
426
                                  const CXXDestructorDecl *DD, CXXDtorType Type,
427
                                  bool ForVirtualBase, bool Delegating,
428
                                  Address This, QualType ThisTy) = 0;
429
430
  /// Emits the VTable definitions required for the given record type.
431
  virtual void emitVTableDefinitions(CodeGenVTables &CGVT,
432
                                     const CXXRecordDecl *RD) = 0;
433
434
  /// Checks if ABI requires extra virtual offset for vtable field.
435
  virtual bool
436
  isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF,
437
                                      CodeGenFunction::VPtr Vptr) = 0;
438
439
  /// Checks if ABI requires to initialize vptrs for given dynamic class.
440
  virtual bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) = 0;
441
442
  /// Get the address point of the vtable for the given base subobject.
443
  virtual llvm::Constant *
444
  getVTableAddressPoint(BaseSubobject Base,
445
                        const CXXRecordDecl *VTableClass) = 0;
446
447
  /// Get the address point of the vtable for the given base subobject while
448
  /// building a constructor or a destructor.
449
  virtual llvm::Value *
450
  getVTableAddressPointInStructor(CodeGenFunction &CGF, const CXXRecordDecl *RD,
451
                                  BaseSubobject Base,
452
                                  const CXXRecordDecl *NearestVBase) = 0;
453
454
  /// Get the address point of the vtable for the given base subobject while
455
  /// building a constexpr.
456
  virtual llvm::Constant *
457
  getVTableAddressPointForConstExpr(BaseSubobject Base,
458
                                    const CXXRecordDecl *VTableClass) = 0;
459
460
  /// Get the address of the vtable for the given record decl which should be
461
  /// used for the vptr at the given offset in RD.
462
  virtual llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
463
                                                CharUnits VPtrOffset) = 0;
464
465
  /// Build a virtual function pointer in the ABI-specific way.
466
  virtual CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF,
467
                                             GlobalDecl GD, Address This,
468
                                             llvm::Type *Ty,
469
                                             SourceLocation Loc) = 0;
470
471
  using DeleteOrMemberCallExpr =
472
      llvm::PointerUnion<const CXXDeleteExpr *, const CXXMemberCallExpr *>;
473
474
  /// Emit the ABI-specific virtual destructor call.
475
  virtual llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
476
                                                 const CXXDestructorDecl *Dtor,
477
                                                 CXXDtorType DtorType,
478
                                                 Address This,
479
                                                 DeleteOrMemberCallExpr E) = 0;
480
481
  virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF,
482
                                                GlobalDecl GD,
483
143
                                                CallArgList &CallArgs) {}
484
485
  /// Emit any tables needed to implement virtual inheritance.  For Itanium,
486
  /// this emits virtual table tables.  For the MSVC++ ABI, this emits virtual
487
  /// base tables.
488
  virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD) = 0;
489
490
  virtual bool exportThunk() = 0;
491
  virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
492
                               GlobalDecl GD, bool ReturnAdjustment) = 0;
493
494
  virtual llvm::Value *performThisAdjustment(CodeGenFunction &CGF,
495
                                             Address This,
496
                                             const ThisAdjustment &TA) = 0;
497
498
  virtual llvm::Value *performReturnAdjustment(CodeGenFunction &CGF,
499
                                               Address Ret,
500
                                               const ReturnAdjustment &RA) = 0;
501
502
  virtual void EmitReturnFromThunk(CodeGenFunction &CGF,
503
                                   RValue RV, QualType ResultType);
504
505
  virtual size_t getSrcArgforCopyCtor(const CXXConstructorDecl *,
506
                                      FunctionArgList &Args) const = 0;
507
508
  /// Gets the offsets of all the virtual base pointers in a given class.
509
  virtual std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD);
510
511
  /// Gets the pure virtual member call function.
512
  virtual StringRef GetPureVirtualCallName() = 0;
513
514
  /// Gets the deleted virtual member call name.
515
  virtual StringRef GetDeletedVirtualCallName() = 0;
516
517
  /**************************** Array cookies ******************************/
518
519
  /// Returns the extra size required in order to store the array
520
  /// cookie for the given new-expression.  May return 0 to indicate that no
521
  /// array cookie is required.
522
  ///
523
  /// Several cases are filtered out before this method is called:
524
  ///   - non-array allocations never need a cookie
525
  ///   - calls to \::operator new(size_t, void*) never need a cookie
526
  ///
527
  /// \param expr - the new-expression being allocated.
528
  virtual CharUnits GetArrayCookieSize(const CXXNewExpr *expr);
529
530
  /// Initialize the array cookie for the given allocation.
531
  ///
532
  /// \param NewPtr - a char* which is the presumed-non-null
533
  ///   return value of the allocation function
534
  /// \param NumElements - the computed number of elements,
535
  ///   potentially collapsed from the multidimensional array case;
536
  ///   always a size_t
537
  /// \param ElementType - the base element allocated type,
538
  ///   i.e. the allocated type after stripping all array types
539
  virtual Address InitializeArrayCookie(CodeGenFunction &CGF,
540
                                        Address NewPtr,
541
                                        llvm::Value *NumElements,
542
                                        const CXXNewExpr *expr,
543
                                        QualType ElementType);
544
545
  /// Reads the array cookie associated with the given pointer,
546
  /// if it has one.
547
  ///
548
  /// \param Ptr - a pointer to the first element in the array
549
  /// \param ElementType - the base element type of elements of the array
550
  /// \param NumElements - an out parameter which will be initialized
551
  ///   with the number of elements allocated, or zero if there is no
552
  ///   cookie
553
  /// \param AllocPtr - an out parameter which will be initialized
554
  ///   with a char* pointing to the address returned by the allocation
555
  ///   function
556
  /// \param CookieSize - an out parameter which will be initialized
557
  ///   with the size of the cookie, or zero if there is no cookie
558
  virtual void ReadArrayCookie(CodeGenFunction &CGF, Address Ptr,
559
                               const CXXDeleteExpr *expr,
560
                               QualType ElementType, llvm::Value *&NumElements,
561
                               llvm::Value *&AllocPtr, CharUnits &CookieSize);
562
563
  /// Return whether the given global decl needs a VTT parameter.
564
  virtual bool NeedsVTTParameter(GlobalDecl GD);
565
566
protected:
567
  /// Returns the extra size required in order to store the array
568
  /// cookie for the given type.  Assumes that an array cookie is
569
  /// required.
570
  virtual CharUnits getArrayCookieSizeImpl(QualType elementType);
571
572
  /// Reads the array cookie for an allocation which is known to have one.
573
  /// This is called by the standard implementation of ReadArrayCookie.
574
  ///
575
  /// \param ptr - a pointer to the allocation made for an array, as a char*
576
  /// \param cookieSize - the computed cookie size of an array
577
  ///
578
  /// Other parameters are as above.
579
  ///
580
  /// \return a size_t
581
  virtual llvm::Value *readArrayCookieImpl(CodeGenFunction &IGF, Address ptr,
582
                                           CharUnits cookieSize);
583
584
public:
585
586
  /*************************** Static local guards ****************************/
587
588
  /// Emits the guarded initializer and destructor setup for the given
589
  /// variable, given that it couldn't be emitted as a constant.
590
  /// If \p PerformInit is false, the initialization has been folded to a
591
  /// constant and should not be performed.
592
  ///
593
  /// The variable may be:
594
  ///   - a static local variable
595
  ///   - a static data member of a class template instantiation
596
  virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
597
                               llvm::GlobalVariable *DeclPtr,
598
                               bool PerformInit) = 0;
599
600
  /// Emit code to force the execution of a destructor during global
601
  /// teardown.  The default implementation of this uses atexit.
602
  ///
603
  /// \param Dtor - a function taking a single pointer argument
604
  /// \param Addr - a pointer to pass to the destructor function.
605
  virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
606
                                  llvm::FunctionCallee Dtor,
607
                                  llvm::Constant *Addr) = 0;
608
609
  /*************************** thread_local initialization ********************/
610
611
  /// Emits ABI-required functions necessary to initialize thread_local
612
  /// variables in this translation unit.
613
  ///
614
  /// \param CXXThreadLocals - The thread_local declarations in this translation
615
  ///        unit.
616
  /// \param CXXThreadLocalInits - If this translation unit contains any
617
  ///        non-constant initialization or non-trivial destruction for
618
  ///        thread_local variables, a list of functions to perform the
619
  ///        initialization.
620
  virtual void EmitThreadLocalInitFuncs(
621
      CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals,
622
      ArrayRef<llvm::Function *> CXXThreadLocalInits,
623
      ArrayRef<const VarDecl *> CXXThreadLocalInitVars) = 0;
624
625
  // Determine if references to thread_local global variables can be made
626
  // directly or require access through a thread wrapper function.
627
  virtual bool usesThreadWrapperFunction(const VarDecl *VD) const = 0;
628
629
  /// Emit a reference to a non-local thread_local variable (including
630
  /// triggering the initialization of all thread_local variables in its
631
  /// translation unit).
632
  virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
633
                                              const VarDecl *VD,
634
                                              QualType LValType) = 0;
635
636
  /// Emit a single constructor/destructor with the given type from a C++
637
  /// constructor Decl.
638
  virtual void emitCXXStructor(GlobalDecl GD) = 0;
639
640
  /// Load a vtable from This, an object of polymorphic type RD, or from one of
641
  /// its virtual bases if it does not have its own vtable. Returns the vtable
642
  /// and the class from which the vtable was loaded.
643
  virtual std::pair<llvm::Value *, const CXXRecordDecl *>
644
  LoadVTablePtr(CodeGenFunction &CGF, Address This,
645
                const CXXRecordDecl *RD) = 0;
646
};
647
648
// Create an instance of a C++ ABI class:
649
650
/// Creates an Itanium-family ABI.
651
CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM);
652
653
/// Creates a Microsoft-family ABI.
654
CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM);
655
656
struct CatchRetScope final : EHScopeStack::Cleanup {
657
  llvm::CatchPadInst *CPI;
658
659
44
  CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {}
660
661
42
  void Emit(CodeGenFunction &CGF, Flags flags) override {
662
42
    llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest");
663
42
    CGF.Builder.CreateCatchRet(CPI, BB);
664
42
    CGF.EmitBlock(BB);
665
42
  }
666
};
667
}
668
}
669
670
#endif