Coverage Report

Created: 2020-09-22 08:39

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/CodeGen/CGCXXABI.h
Line
Count
Source (jump to first uncovered line)
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
29.7k
    : CGM(CGM), MangleCtx(CGM.getContext().createMangleContext()) {}
51
52
protected:
53
191k
  ImplicitParamDecl *getThisDecl(CodeGenFunction &CGF) {
54
191k
    return CGF.CXXABIThisDecl;
55
191k
  }
56
2.10k
  llvm::Value *getThisValue(CodeGenFunction &CGF) {
57
2.10k
    return CGF.CXXABIThisValue;
58
2.10k
  }
59
902
  Address getThisAddress(CodeGenFunction &CGF) {
60
902
    return Address(CGF.CXXABIThisValue, CGF.CXXABIThisAlignment);
61
902
  }
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
94.9k
  ImplicitParamDecl *&getStructorImplicitParamDecl(CodeGenFunction &CGF) {
70
94.9k
    return CGF.CXXStructorImplicitParamDecl;
71
94.9k
  }
72
1.43k
  llvm::Value *&getStructorImplicitParamValue(CodeGenFunction &CGF) {
73
1.43k
    return CGF.CXXStructorImplicitParamValue;
74
1.43k
  }
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
370k
  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
3.07M
  MangleContext &getMangleContext() {
98
3.07M
    return *MangleCtx;
99
3.07M
  }
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
748k
  virtual bool HasThisReturn(GlobalDecl GD) const { return false; }
108
109
406k
  virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; }
110
111
1.33k
  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
  /// Find the LLVM type used to represent the given member pointer
150
  /// type.
151
  virtual llvm::Type *
152
  ConvertMemberPointerType(const MemberPointerType *MPT);
153
154
  /// Load a member function from an object and a member function
155
  /// pointer.  Apply the this-adjustment and set 'This' to the
156
  /// adjusted value.
157
  virtual CGCallee EmitLoadOfMemberFunctionPointer(
158
      CodeGenFunction &CGF, const Expr *E, Address This,
159
      llvm::Value *&ThisPtrForCall, llvm::Value *MemPtr,
160
      const MemberPointerType *MPT);
161
162
  /// Calculate an l-value from an object and a data member pointer.
163
  virtual llvm::Value *
164
  EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E,
165
                               Address Base, llvm::Value *MemPtr,
166
                               const MemberPointerType *MPT);
167
168
  /// Perform a derived-to-base, base-to-derived, or bitcast member
169
  /// pointer conversion.
170
  virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
171
                                                   const CastExpr *E,
172
                                                   llvm::Value *Src);
173
174
  /// Perform a derived-to-base, base-to-derived, or bitcast member
175
  /// pointer conversion on a constant value.
176
  virtual llvm::Constant *EmitMemberPointerConversion(const CastExpr *E,
177
                                                      llvm::Constant *Src);
178
179
  /// Return true if the given member pointer can be zero-initialized
180
  /// (in the C++ sense) with an LLVM zeroinitializer.
181
  virtual bool isZeroInitializable(const MemberPointerType *MPT);
182
183
  /// Return whether or not a member pointers type is convertible to an IR type.
184
461
  virtual bool isMemberPointerConvertible(const MemberPointerType *MPT) const {
185
461
    return true;
186
461
  }
187
188
  /// Create a null member pointer of the given type.
189
  virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT);
190
191
  /// Create a member pointer for the given method.
192
  virtual llvm::Constant *EmitMemberFunctionPointer(const CXXMethodDecl *MD);
193
194
  /// Create a member pointer for the given field.
195
  virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
196
                                                CharUnits offset);
197
198
  /// Create a member pointer for the given member pointer constant.
199
  virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT);
200
201
  /// Emit a comparison between two member pointers.  Returns an i1.
202
  virtual llvm::Value *
203
  EmitMemberPointerComparison(CodeGenFunction &CGF,
204
                              llvm::Value *L,
205
                              llvm::Value *R,
206
                              const MemberPointerType *MPT,
207
                              bool Inequality);
208
209
  /// Determine if a member pointer is non-null.  Returns an i1.
210
  virtual llvm::Value *
211
  EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
212
                             llvm::Value *MemPtr,
213
                             const MemberPointerType *MPT);
214
215
protected:
216
  /// A utility method for computing the offset required for the given
217
  /// base-to-derived or derived-to-base member-pointer conversion.
218
  /// Does not handle virtual conversions (in case we ever fully
219
  /// support an ABI that allows this).  Returns null if no adjustment
220
  /// is required.
221
  llvm::Constant *getMemberPointerAdjustment(const CastExpr *E);
222
223
  /// Computes the non-virtual adjustment needed for a member pointer
224
  /// conversion along an inheritance path stored in an APValue.  Unlike
225
  /// getMemberPointerAdjustment(), the adjustment can be negative if the path
226
  /// is from a derived type to a base type.
227
  CharUnits getMemberPointerPathAdjustment(const APValue &MP);
228
229
public:
230
  virtual void emitVirtualObjectDelete(CodeGenFunction &CGF,
231
                                       const CXXDeleteExpr *DE,
232
                                       Address Ptr, QualType ElementType,
233
                                       const CXXDestructorDecl *Dtor) = 0;
234
  virtual void emitRethrow(CodeGenFunction &CGF, bool isNoReturn) = 0;
235
  virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0;
236
0
  virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; }
237
238
  /// Determine whether it's possible to emit a vtable for \p RD, even
239
  /// though we do not know that the vtable has been marked as used by semantic
240
  /// analysis.
241
  virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const = 0;
242
243
  virtual void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) = 0;
244
245
  virtual llvm::CallInst *
246
  emitTerminateForUnexpectedException(CodeGenFunction &CGF,
247
                                      llvm::Value *Exn);
248
249
  virtual llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) = 0;
250
  virtual CatchTypeInfo
251
  getAddrOfCXXCatchHandlerType(QualType Ty, QualType CatchHandlerType) = 0;
252
  virtual CatchTypeInfo getCatchAllTypeInfo();
253
254
  virtual bool shouldTypeidBeNullChecked(bool IsDeref,
255
                                         QualType SrcRecordTy) = 0;
256
  virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0;
257
  virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy,
258
                                  Address ThisPtr,
259
                                  llvm::Type *StdTypeInfoPtrTy) = 0;
260
261
  virtual bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr,
262
                                                  QualType SrcRecordTy) = 0;
263
264
  virtual llvm::Value *
265
  EmitDynamicCastCall(CodeGenFunction &CGF, Address Value,
266
                      QualType SrcRecordTy, QualType DestTy,
267
                      QualType DestRecordTy, llvm::BasicBlock *CastEnd) = 0;
268
269
  virtual llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF,
270
                                             Address Value,
271
                                             QualType SrcRecordTy,
272
                                             QualType DestTy) = 0;
273
274
  virtual bool EmitBadCastCall(CodeGenFunction &CGF) = 0;
275
276
  virtual llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF,
277
                                                 Address This,
278
                                                 const CXXRecordDecl *ClassDecl,
279
                                        const CXXRecordDecl *BaseClassDecl) = 0;
280
281
  virtual llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF,
282
                                                          const CXXRecordDecl *RD);
283
284
  /// Emit the code to initialize hidden members required
285
  /// to handle virtual inheritance, if needed by the ABI.
286
  virtual void
287
  initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF,
288
403
                                            const CXXRecordDecl *RD) {}
289
290
  /// Emit constructor variants required by this ABI.
291
  virtual void EmitCXXConstructors(const CXXConstructorDecl *D) = 0;
292
293
  /// Additional implicit arguments to add to the beginning (Prefix) and end
294
  /// (Suffix) of a constructor / destructor arg list.
295
  ///
296
  /// Note that Prefix should actually be inserted *after* the first existing
297
  /// arg; `this` arguments always come first.
298
  struct AddedStructorArgs {
299
    struct Arg {
300
      llvm::Value *Value;
301
      QualType Type;
302
    };
303
    SmallVector<Arg, 1> Prefix;
304
    SmallVector<Arg, 1> Suffix;
305
49.9k
    AddedStructorArgs() = default;
306
    AddedStructorArgs(SmallVector<Arg, 1> P, SmallVector<Arg, 1> S)
307
608
        : Prefix(std::move(P)), Suffix(std::move(S)) {}
308
136
    static AddedStructorArgs prefix(SmallVector<Arg, 1> Args) {
309
136
      return {std::move(Args), {}};
310
136
    }
311
472
    static AddedStructorArgs suffix(SmallVector<Arg, 1> Args) {
312
472
      return {{}, std::move(Args)};
313
472
    }
314
  };
315
316
  /// Similar to AddedStructorArgs, but only notes the number of additional
317
  /// arguments.
318
  struct AddedStructorArgCounts {
319
    unsigned Prefix = 0;
320
    unsigned Suffix = 0;
321
277k
    AddedStructorArgCounts() = default;
322
51.7k
    AddedStructorArgCounts(unsigned P, unsigned S) : Prefix(P), Suffix(S) {}
323
1.11k
    static AddedStructorArgCounts prefix(unsigned N) { return {N, 0}; }
324
0
    static AddedStructorArgCounts suffix(unsigned N) { return {0, N}; }
325
  };
326
327
  /// Build the signature of the given constructor or destructor variant by
328
  /// adding any required parameters.  For convenience, ArgTys has been
329
  /// initialized with the type of 'this'.
330
  virtual AddedStructorArgCounts
331
  buildStructorSignature(GlobalDecl GD,
332
                         SmallVectorImpl<CanQualType> &ArgTys) = 0;
333
334
  /// Returns true if the given destructor type should be emitted as a linkonce
335
  /// delegating thunk, regardless of whether the dtor is defined in this TU or
336
  /// not.
337
  virtual bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
338
                                      CXXDtorType DT) const = 0;
339
340
  virtual void setCXXDestructorDLLStorage(llvm::GlobalValue *GV,
341
                                          const CXXDestructorDecl *Dtor,
342
                                          CXXDtorType DT) const;
343
344
  virtual llvm::GlobalValue::LinkageTypes
345
  getCXXDestructorLinkage(GVALinkage Linkage, const CXXDestructorDecl *Dtor,
346
                          CXXDtorType DT) const;
347
348
  /// Emit destructor variants required by this ABI.
349
  virtual void EmitCXXDestructors(const CXXDestructorDecl *D) = 0;
350
351
  /// Get the type of the implicit "this" parameter used by a method. May return
352
  /// zero if no specific type is applicable, e.g. if the ABI expects the "this"
353
  /// parameter to point to some artificial offset in a complete object due to
354
  /// vbases being reordered.
355
  virtual const CXXRecordDecl *
356
280k
  getThisArgumentTypeForMethod(const CXXMethodDecl *MD) {
357
280k
    return MD->getParent();
358
280k
  }
359
360
  /// Perform ABI-specific "this" argument adjustment required prior to
361
  /// a call of a virtual function.
362
  /// The "VirtualCall" argument is true iff the call itself is virtual.
363
  virtual Address
364
  adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD,
365
1.13k
                                           Address This, bool VirtualCall) {
366
1.13k
    return This;
367
1.13k
  }
368
369
  /// Build a parameter variable suitable for 'this'.
370
  void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params);
371
372
  /// Insert any ABI-specific implicit parameters into the parameter list for a
373
  /// function.  This generally involves extra data for constructors and
374
  /// destructors.
375
  ///
376
  /// ABIs may also choose to override the return type, which has been
377
  /// initialized with the type of 'this' if HasThisReturn(CGF.CurGD) is true or
378
  /// the formal return type of the function otherwise.
379
  virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy,
380
                                         FunctionArgList &Params) = 0;
381
382
  /// Get the ABI-specific "this" parameter adjustment to apply in the prologue
383
  /// of a virtual function.
384
0
  virtual CharUnits getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
385
0
    return CharUnits::Zero();
386
0
  }
387
388
  /// Emit the ABI-specific prolog for the function.
389
  virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0;
390
391
  virtual AddedStructorArgs
392
  getImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D,
393
                             CXXCtorType Type, bool ForVirtualBase,
394
                             bool Delegating) = 0;
395
396
  /// Add any ABI-specific implicit arguments needed to call a constructor.
397
  ///
398
  /// \return The number of arguments added at the beginning and end of the
399
  /// call, which is typically zero or one.
400
  AddedStructorArgCounts
401
  addImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D,
402
                             CXXCtorType Type, bool ForVirtualBase,
403
                             bool Delegating, CallArgList &Args);
404
405
  /// Get the implicit (second) parameter that comes after the "this" pointer,
406
  /// or nullptr if there is isn't one.
407
  virtual llvm::Value *
408
  getCXXDestructorImplicitParam(CodeGenFunction &CGF,
409
                                const CXXDestructorDecl *DD, CXXDtorType Type,
410
                                bool ForVirtualBase, bool Delegating) = 0;
411
412
  /// Emit the destructor call.
413
  virtual void EmitDestructorCall(CodeGenFunction &CGF,
414
                                  const CXXDestructorDecl *DD, CXXDtorType Type,
415
                                  bool ForVirtualBase, bool Delegating,
416
                                  Address This, QualType ThisTy) = 0;
417
418
  /// Emits the VTable definitions required for the given record type.
419
  virtual void emitVTableDefinitions(CodeGenVTables &CGVT,
420
                                     const CXXRecordDecl *RD) = 0;
421
422
  /// Checks if ABI requires extra virtual offset for vtable field.
423
  virtual bool
424
  isVirtualOffsetNeededForVTableField(CodeGenFunction &CGF,
425
                                      CodeGenFunction::VPtr Vptr) = 0;
426
427
  /// Checks if ABI requires to initialize vptrs for given dynamic class.
428
  virtual bool doStructorsInitializeVPtrs(const CXXRecordDecl *VTableClass) = 0;
429
430
  /// Get the address point of the vtable for the given base subobject.
431
  virtual llvm::Constant *
432
  getVTableAddressPoint(BaseSubobject Base,
433
                        const CXXRecordDecl *VTableClass) = 0;
434
435
  /// Get the address point of the vtable for the given base subobject while
436
  /// building a constructor or a destructor.
437
  virtual llvm::Value *
438
  getVTableAddressPointInStructor(CodeGenFunction &CGF, const CXXRecordDecl *RD,
439
                                  BaseSubobject Base,
440
                                  const CXXRecordDecl *NearestVBase) = 0;
441
442
  /// Get the address point of the vtable for the given base subobject while
443
  /// building a constexpr.
444
  virtual llvm::Constant *
445
  getVTableAddressPointForConstExpr(BaseSubobject Base,
446
                                    const CXXRecordDecl *VTableClass) = 0;
447
448
  /// Get the address of the vtable for the given record decl which should be
449
  /// used for the vptr at the given offset in RD.
450
  virtual llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
451
                                                CharUnits VPtrOffset) = 0;
452
453
  /// Build a virtual function pointer in the ABI-specific way.
454
  virtual CGCallee getVirtualFunctionPointer(CodeGenFunction &CGF,
455
                                             GlobalDecl GD, Address This,
456
                                             llvm::Type *Ty,
457
                                             SourceLocation Loc) = 0;
458
459
  using DeleteOrMemberCallExpr =
460
      llvm::PointerUnion<const CXXDeleteExpr *, const CXXMemberCallExpr *>;
461
462
  /// Emit the ABI-specific virtual destructor call.
463
  virtual llvm::Value *EmitVirtualDestructorCall(CodeGenFunction &CGF,
464
                                                 const CXXDestructorDecl *Dtor,
465
                                                 CXXDtorType DtorType,
466
                                                 Address This,
467
                                                 DeleteOrMemberCallExpr E) = 0;
468
469
  virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF,
470
                                                GlobalDecl GD,
471
151
                                                CallArgList &CallArgs) {}
472
473
  /// Emit any tables needed to implement virtual inheritance.  For Itanium,
474
  /// this emits virtual table tables.  For the MSVC++ ABI, this emits virtual
475
  /// base tables.
476
  virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD) = 0;
477
478
  virtual bool exportThunk() = 0;
479
  virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable,
480
                               GlobalDecl GD, bool ReturnAdjustment) = 0;
481
482
  virtual llvm::Value *performThisAdjustment(CodeGenFunction &CGF,
483
                                             Address This,
484
                                             const ThisAdjustment &TA) = 0;
485
486
  virtual llvm::Value *performReturnAdjustment(CodeGenFunction &CGF,
487
                                               Address Ret,
488
                                               const ReturnAdjustment &RA) = 0;
489
490
  virtual void EmitReturnFromThunk(CodeGenFunction &CGF,
491
                                   RValue RV, QualType ResultType);
492
493
  virtual size_t getSrcArgforCopyCtor(const CXXConstructorDecl *,
494
                                      FunctionArgList &Args) const = 0;
495
496
  /// Gets the offsets of all the virtual base pointers in a given class.
497
  virtual std::vector<CharUnits> getVBPtrOffsets(const CXXRecordDecl *RD);
498
499
  /// Gets the pure virtual member call function.
500
  virtual StringRef GetPureVirtualCallName() = 0;
501
502
  /// Gets the deleted virtual member call name.
503
  virtual StringRef GetDeletedVirtualCallName() = 0;
504
505
  /**************************** Array cookies ******************************/
506
507
  /// Returns the extra size required in order to store the array
508
  /// cookie for the given new-expression.  May return 0 to indicate that no
509
  /// array cookie is required.
510
  ///
511
  /// Several cases are filtered out before this method is called:
512
  ///   - non-array allocations never need a cookie
513
  ///   - calls to \::operator new(size_t, void*) never need a cookie
514
  ///
515
  /// \param expr - the new-expression being allocated.
516
  virtual CharUnits GetArrayCookieSize(const CXXNewExpr *expr);
517
518
  /// Initialize the array cookie for the given allocation.
519
  ///
520
  /// \param NewPtr - a char* which is the presumed-non-null
521
  ///   return value of the allocation function
522
  /// \param NumElements - the computed number of elements,
523
  ///   potentially collapsed from the multidimensional array case;
524
  ///   always a size_t
525
  /// \param ElementType - the base element allocated type,
526
  ///   i.e. the allocated type after stripping all array types
527
  virtual Address InitializeArrayCookie(CodeGenFunction &CGF,
528
                                        Address NewPtr,
529
                                        llvm::Value *NumElements,
530
                                        const CXXNewExpr *expr,
531
                                        QualType ElementType);
532
533
  /// Reads the array cookie associated with the given pointer,
534
  /// if it has one.
535
  ///
536
  /// \param Ptr - a pointer to the first element in the array
537
  /// \param ElementType - the base element type of elements of the array
538
  /// \param NumElements - an out parameter which will be initialized
539
  ///   with the number of elements allocated, or zero if there is no
540
  ///   cookie
541
  /// \param AllocPtr - an out parameter which will be initialized
542
  ///   with a char* pointing to the address returned by the allocation
543
  ///   function
544
  /// \param CookieSize - an out parameter which will be initialized
545
  ///   with the size of the cookie, or zero if there is no cookie
546
  virtual void ReadArrayCookie(CodeGenFunction &CGF, Address Ptr,
547
                               const CXXDeleteExpr *expr,
548
                               QualType ElementType, llvm::Value *&NumElements,
549
                               llvm::Value *&AllocPtr, CharUnits &CookieSize);
550
551
  /// Return whether the given global decl needs a VTT parameter.
552
  virtual bool NeedsVTTParameter(GlobalDecl GD);
553
554
protected:
555
  /// Returns the extra size required in order to store the array
556
  /// cookie for the given type.  Assumes that an array cookie is
557
  /// required.
558
  virtual CharUnits getArrayCookieSizeImpl(QualType elementType);
559
560
  /// Reads the array cookie for an allocation which is known to have one.
561
  /// This is called by the standard implementation of ReadArrayCookie.
562
  ///
563
  /// \param ptr - a pointer to the allocation made for an array, as a char*
564
  /// \param cookieSize - the computed cookie size of an array
565
  ///
566
  /// Other parameters are as above.
567
  ///
568
  /// \return a size_t
569
  virtual llvm::Value *readArrayCookieImpl(CodeGenFunction &IGF, Address ptr,
570
                                           CharUnits cookieSize);
571
572
public:
573
574
  /*************************** Static local guards ****************************/
575
576
  /// Emits the guarded initializer and destructor setup for the given
577
  /// variable, given that it couldn't be emitted as a constant.
578
  /// If \p PerformInit is false, the initialization has been folded to a
579
  /// constant and should not be performed.
580
  ///
581
  /// The variable may be:
582
  ///   - a static local variable
583
  ///   - a static data member of a class template instantiation
584
  virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
585
                               llvm::GlobalVariable *DeclPtr,
586
                               bool PerformInit) = 0;
587
588
  /// Emit code to force the execution of a destructor during global
589
  /// teardown.  The default implementation of this uses atexit.
590
  ///
591
  /// \param Dtor - a function taking a single pointer argument
592
  /// \param Addr - a pointer to pass to the destructor function.
593
  virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
594
                                  llvm::FunctionCallee Dtor,
595
                                  llvm::Constant *Addr) = 0;
596
597
  /*************************** thread_local initialization ********************/
598
599
  /// Emits ABI-required functions necessary to initialize thread_local
600
  /// variables in this translation unit.
601
  ///
602
  /// \param CXXThreadLocals - The thread_local declarations in this translation
603
  ///        unit.
604
  /// \param CXXThreadLocalInits - If this translation unit contains any
605
  ///        non-constant initialization or non-trivial destruction for
606
  ///        thread_local variables, a list of functions to perform the
607
  ///        initialization.
608
  virtual void EmitThreadLocalInitFuncs(
609
      CodeGenModule &CGM, ArrayRef<const VarDecl *> CXXThreadLocals,
610
      ArrayRef<llvm::Function *> CXXThreadLocalInits,
611
      ArrayRef<const VarDecl *> CXXThreadLocalInitVars) = 0;
612
613
  // Determine if references to thread_local global variables can be made
614
  // directly or require access through a thread wrapper function.
615
  virtual bool usesThreadWrapperFunction(const VarDecl *VD) const = 0;
616
617
  /// Emit a reference to a non-local thread_local variable (including
618
  /// triggering the initialization of all thread_local variables in its
619
  /// translation unit).
620
  virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
621
                                              const VarDecl *VD,
622
                                              QualType LValType) = 0;
623
624
  /// Emit a single constructor/destructor with the given type from a C++
625
  /// constructor Decl.
626
  virtual void emitCXXStructor(GlobalDecl GD) = 0;
627
628
  /// Load a vtable from This, an object of polymorphic type RD, or from one of
629
  /// its virtual bases if it does not have its own vtable. Returns the vtable
630
  /// and the class from which the vtable was loaded.
631
  virtual std::pair<llvm::Value *, const CXXRecordDecl *>
632
  LoadVTablePtr(CodeGenFunction &CGF, Address This,
633
                const CXXRecordDecl *RD) = 0;
634
};
635
636
// Create an instance of a C++ ABI class:
637
638
/// Creates an Itanium-family ABI.
639
CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM);
640
641
/// Creates a Microsoft-family ABI.
642
CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM);
643
644
struct CatchRetScope final : EHScopeStack::Cleanup {
645
  llvm::CatchPadInst *CPI;
646
647
124
  CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {}
648
649
122
  void Emit(CodeGenFunction &CGF, Flags flags) override {
650
122
    llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest");
651
122
    CGF.Builder.CreateCatchRet(CPI, BB);
652
122
    CGF.EmitBlock(BB);
653
122
  }
654
};
655
}
656
}
657
658
#endif