Coverage Report

Created: 2021-08-24 07:12

/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.
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// 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
15
#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;
26
}
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28
namespace clang {
29
class CastExpr;
30
class CXXConstructorDecl;
31
class CXXDestructorDecl;
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class CXXMethodDecl;
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class CXXRecordDecl;
34
class FieldDecl;
35
class MangleContext;
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37
namespace CodeGen {
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class CGCallee;
39
class CodeGenFunction;
40
class CodeGenModule;
41
struct CatchTypeInfo;
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43
/// Implements C++ ABI-specific code generation functions.
44
class CGCXXABI {
45
protected:
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  CodeGenModule &CGM;
47
  std::unique_ptr<MangleContext> MangleCtx;
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49
  CGCXXABI(CodeGenModule &CGM)
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45.6k
    : CGM(CGM), MangleCtx(CGM.getContext().createMangleContext()) {}
51
52
protected:
53
210k
  ImplicitParamDecl *getThisDecl(CodeGenFunction &CGF) {
54
210k
    return CGF.CXXABIThisDecl;
55
210k
  }
56
2.14k
  llvm::Value *getThisValue(CodeGenFunction &CGF) {
57
2.14k
    return CGF.CXXABIThisValue;
58
2.14k
  }
59
903
  Address getThisAddress(CodeGenFunction &CGF) {
60
903
    return Address(CGF.CXXABIThisValue, CGF.CXXABIThisAlignment);
61
903
  }
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
104k
  ImplicitParamDecl *&getStructorImplicitParamDecl(CodeGenFunction &CGF) {
70
104k
    return CGF.CXXStructorImplicitParamDecl;
71
104k
  }
72
1.44k
  llvm::Value *&getStructorImplicitParamValue(CodeGenFunction &CGF) {
73
1.44k
    return CGF.CXXStructorImplicitParamValue;
74
1.44k
  }
75
76
  /// Loads the incoming C++ this pointer as it was passed by the caller.
77
  llvm::Value *loadIncomingCXXThis(CodeGenFunction &CGF);
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79
  void setCXXABIThisValue(CodeGenFunction &CGF, llvm::Value *ThisPtr);
80
81
403k
  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
3.51M
  MangleContext &getMangleContext() {
98
3.51M
    return *MangleCtx;
99
3.51M
  }
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
883k
  virtual bool HasThisReturn(GlobalDecl GD) const { return false; }
108
109
441k
  virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; }
110
111
37.7k
  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
7
  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
0
  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
437
  isPermittedToBeHomogeneousAggregate(const CXXRecordDecl *RD) const {
153
437
    return true;
154
437
  };
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
473
  virtual bool isMemberPointerConvertible(const MemberPointerType *MPT) const {
192
473
    return true;
193
473
  }
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);
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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
0
  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
416
                                            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
54.1k
    AddedStructorArgs() = default;
307
    AddedStructorArgs(SmallVector<Arg, 1> P, SmallVector<Arg, 1> S)
308
611
        : Prefix(std::move(P)), Suffix(std::move(S)) {}
309
139
    static AddedStructorArgs prefix(SmallVector<Arg, 1> Args) {
310
139
      return {std::move(Args), {}};
311
139
    }
312
472
    static AddedStructorArgs suffix(SmallVector<Arg, 1> Args) {
313
472
      return {{}, std::move(Args)};
314
472
    }
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
298k
    AddedStructorArgCounts() = default;
323
55.8k
    AddedStructorArgCounts(unsigned P, unsigned S) : Prefix(P), Suffix(S) {}
324
1.14k
    static AddedStructorArgCounts prefix(unsigned N) { return {N, 0}; }
325
0
    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
318k
  getThisArgumentTypeForMethod(const CXXMethodDecl *MD) {
358
318k
    return MD->getParent();
359
318k
  }
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
1.17k
                                           Address This, bool VirtualCall) {
367
1.17k
    return This;
368
1.17k
  }
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
0
  virtual CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
386
0
    return CharUnits::Zero();
387
0
  }
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
153
                                                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
125
  CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {}
649
650
123
  void Emit(CodeGenFunction &CGF, Flags flags) override {
651
123
    llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest");
652
123
    CGF.Builder.CreateCatchRet(CPI, BB);
653
123
    CGF.EmitBlock(BB);
654
123
  }
655
};
656
}
657
}
658
659
#endif