Coverage Report

Created: 2022-01-18 06:27

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/CodeGen/CGObjCRuntime.cpp
Line
Count
Source (jump to first uncovered line)
1
//==- CGObjCRuntime.cpp - Interface to Shared Objective-C Runtime Features ==//
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 abstract class defines the interface for Objective-C runtime-specific
10
// code generation.  It provides some concrete helper methods for functionality
11
// shared between all (or most) of the Objective-C runtimes supported by clang.
12
//
13
//===----------------------------------------------------------------------===//
14
15
#include "CGObjCRuntime.h"
16
#include "CGCXXABI.h"
17
#include "CGCleanup.h"
18
#include "CGRecordLayout.h"
19
#include "CodeGenFunction.h"
20
#include "CodeGenModule.h"
21
#include "clang/AST/RecordLayout.h"
22
#include "clang/AST/StmtObjC.h"
23
#include "clang/CodeGen/CGFunctionInfo.h"
24
#include "clang/CodeGen/CodeGenABITypes.h"
25
#include "llvm/Support/SaveAndRestore.h"
26
27
using namespace clang;
28
using namespace CodeGen;
29
30
uint64_t CGObjCRuntime::ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
31
                                              const ObjCInterfaceDecl *OID,
32
463
                                              const ObjCIvarDecl *Ivar) {
33
463
  return CGM.getContext().lookupFieldBitOffset(OID, nullptr, Ivar) /
34
463
         CGM.getContext().getCharWidth();
35
463
}
36
37
uint64_t CGObjCRuntime::ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
38
                                              const ObjCImplementationDecl *OID,
39
2.47k
                                              const ObjCIvarDecl *Ivar) {
40
2.47k
  return CGM.getContext().lookupFieldBitOffset(OID->getClassInterface(), OID,
41
2.47k
                                               Ivar) /
42
2.47k
         CGM.getContext().getCharWidth();
43
2.47k
}
44
45
unsigned CGObjCRuntime::ComputeBitfieldBitOffset(
46
    CodeGen::CodeGenModule &CGM,
47
    const ObjCInterfaceDecl *ID,
48
245
    const ObjCIvarDecl *Ivar) {
49
245
  return CGM.getContext().lookupFieldBitOffset(ID, ID->getImplementation(),
50
245
                                               Ivar);
51
245
}
52
53
LValue CGObjCRuntime::EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF,
54
                                               const ObjCInterfaceDecl *OID,
55
                                               llvm::Value *BaseValue,
56
                                               const ObjCIvarDecl *Ivar,
57
                                               unsigned CVRQualifiers,
58
2.22k
                                               llvm::Value *Offset) {
59
  // Compute (type*) ( (char *) BaseValue + Offset)
60
2.22k
  QualType InterfaceTy{OID->getTypeForDecl(), 0};
61
2.22k
  QualType ObjectPtrTy =
62
2.22k
      CGF.CGM.getContext().getObjCObjectPointerType(InterfaceTy);
63
2.22k
  QualType IvarTy =
64
2.22k
      Ivar->getUsageType(ObjectPtrTy).withCVRQualifiers(CVRQualifiers);
65
2.22k
  llvm::Type *LTy = CGF.CGM.getTypes().ConvertTypeForMem(IvarTy);
66
2.22k
  llvm::Value *V = CGF.Builder.CreateBitCast(BaseValue, CGF.Int8PtrTy);
67
2.22k
  V = CGF.Builder.CreateInBoundsGEP(CGF.Int8Ty, V, Offset, "add.ptr");
68
69
2.22k
  if (!Ivar->isBitField()) {
70
2.09k
    V = CGF.Builder.CreateBitCast(V, llvm::PointerType::getUnqual(LTy));
71
2.09k
    LValue LV = CGF.MakeNaturalAlignAddrLValue(V, IvarTy);
72
2.09k
    return LV;
73
2.09k
  }
74
75
  // We need to compute an access strategy for this bit-field. We are given the
76
  // offset to the first byte in the bit-field, the sub-byte offset is taken
77
  // from the original layout. We reuse the normal bit-field access strategy by
78
  // treating this as an access to a struct where the bit-field is in byte 0,
79
  // and adjust the containing type size as appropriate.
80
  //
81
  // FIXME: Note that currently we make a very conservative estimate of the
82
  // alignment of the bit-field, because (a) it is not clear what guarantees the
83
  // runtime makes us, and (b) we don't have a way to specify that the struct is
84
  // at an alignment plus offset.
85
  //
86
  // Note, there is a subtle invariant here: we can only call this routine on
87
  // non-synthesized ivars but we may be called for synthesized ivars.  However,
88
  // a synthesized ivar can never be a bit-field, so this is safe.
89
136
  uint64_t FieldBitOffset =
90
136
      CGF.CGM.getContext().lookupFieldBitOffset(OID, nullptr, Ivar);
91
136
  uint64_t BitOffset = FieldBitOffset % CGF.CGM.getContext().getCharWidth();
92
136
  uint64_t AlignmentBits = CGF.CGM.getTarget().getCharAlign();
93
136
  uint64_t BitFieldSize = Ivar->getBitWidthValue(CGF.getContext());
94
136
  CharUnits StorageSize = CGF.CGM.getContext().toCharUnitsFromBits(
95
136
      llvm::alignTo(BitOffset + BitFieldSize, AlignmentBits));
96
136
  CharUnits Alignment = CGF.CGM.getContext().toCharUnitsFromBits(AlignmentBits);
97
98
  // Allocate a new CGBitFieldInfo object to describe this access.
99
  //
100
  // FIXME: This is incredibly wasteful, these should be uniqued or part of some
101
  // layout object. However, this is blocked on other cleanups to the
102
  // Objective-C code, so for now we just live with allocating a bunch of these
103
  // objects.
104
136
  CGBitFieldInfo *Info = new (CGF.CGM.getContext()) CGBitFieldInfo(
105
136
    CGBitFieldInfo::MakeInfo(CGF.CGM.getTypes(), Ivar, BitOffset, BitFieldSize,
106
136
                             CGF.CGM.getContext().toBits(StorageSize),
107
136
                             CharUnits::fromQuantity(0)));
108
109
136
  Address Addr(V, Alignment);
110
136
  Addr = CGF.Builder.CreateElementBitCast(Addr,
111
136
                                   llvm::Type::getIntNTy(CGF.getLLVMContext(),
112
136
                                                         Info->StorageSize));
113
136
  return LValue::MakeBitfield(Addr, *Info, IvarTy,
114
136
                              LValueBaseInfo(AlignmentSource::Decl),
115
136
                              TBAAAccessInfo());
116
2.22k
}
117
118
namespace {
119
  struct CatchHandler {
120
    const VarDecl *Variable;
121
    const Stmt *Body;
122
    llvm::BasicBlock *Block;
123
    llvm::Constant *TypeInfo;
124
    /// Flags used to differentiate cleanups and catchalls in Windows SEH
125
    unsigned Flags;
126
  };
127
128
  struct CallObjCEndCatch final : EHScopeStack::Cleanup {
129
    CallObjCEndCatch(bool MightThrow, llvm::FunctionCallee Fn)
130
176
        : MightThrow(MightThrow), Fn(Fn) {}
131
    bool MightThrow;
132
    llvm::FunctionCallee Fn;
133
134
208
    void Emit(CodeGenFunction &CGF, Flags flags) override {
135
208
      if (MightThrow)
136
25
        CGF.EmitRuntimeCallOrInvoke(Fn);
137
183
      else
138
183
        CGF.EmitNounwindRuntimeCall(Fn);
139
208
    }
140
  };
141
}
142
143
void CGObjCRuntime::EmitTryCatchStmt(CodeGenFunction &CGF,
144
                                     const ObjCAtTryStmt &S,
145
                                     llvm::FunctionCallee beginCatchFn,
146
                                     llvm::FunctionCallee endCatchFn,
147
185
                                     llvm::FunctionCallee exceptionRethrowFn) {
148
  // Jump destination for falling out of catch bodies.
149
185
  CodeGenFunction::JumpDest Cont;
150
185
  if (S.getNumCatchStmts())
151
181
    Cont = CGF.getJumpDestInCurrentScope("eh.cont");
152
153
185
  bool useFunclets = EHPersonality::get(CGF).usesFuncletPads();
154
155
185
  CodeGenFunction::FinallyInfo FinallyInfo;
156
185
  if (!useFunclets)
157
170
    if (const ObjCAtFinallyStmt *Finally = S.getFinallyStmt())
158
11
      FinallyInfo.enter(CGF, Finally->getFinallyBody(),
159
11
                        beginCatchFn, endCatchFn, exceptionRethrowFn);
160
161
185
  SmallVector<CatchHandler, 8> Handlers;
162
163
164
  // Enter the catch, if there is one.
165
185
  if (S.getNumCatchStmts()) {
166
226
    for (const ObjCAtCatchStmt *CatchStmt : S.catch_stmts()) {
167
226
      const VarDecl *CatchDecl = CatchStmt->getCatchParamDecl();
168
169
226
      Handlers.push_back(CatchHandler());
170
226
      CatchHandler &Handler = Handlers.back();
171
226
      Handler.Variable = CatchDecl;
172
226
      Handler.Body = CatchStmt->getCatchBody();
173
226
      Handler.Block = CGF.createBasicBlock("catch");
174
226
      Handler.Flags = 0;
175
176
      // @catch(...) always matches.
177
226
      if (!CatchDecl) {
178
43
        auto catchAll = getCatchAllTypeInfo();
179
43
        Handler.TypeInfo = catchAll.RTTI;
180
43
        Handler.Flags = catchAll.Flags;
181
        // Don't consider any other catches.
182
43
        break;
183
43
      }
184
185
183
      Handler.TypeInfo = GetEHType(CatchDecl->getType());
186
183
    }
187
188
181
    EHCatchScope *Catch = CGF.EHStack.pushCatch(Handlers.size());
189
407
    for (unsigned I = 0, E = Handlers.size(); I != E; 
++I226
)
190
226
      Catch->setHandler(I, { Handlers[I].TypeInfo, Handlers[I].Flags }, Handlers[I].Block);
191
181
  }
192
193
185
  if (useFunclets)
194
15
    if (const ObjCAtFinallyStmt *Finally = S.getFinallyStmt()) {
195
0
        CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
196
0
        if (!CGF.CurSEHParent)
197
0
            CGF.CurSEHParent = cast<NamedDecl>(CGF.CurFuncDecl);
198
        // Outline the finally block.
199
0
        const Stmt *FinallyBlock = Finally->getFinallyBody();
200
0
        HelperCGF.startOutlinedSEHHelper(CGF, /*isFilter*/false, FinallyBlock);
201
202
        // Emit the original filter expression, convert to i32, and return.
203
0
        HelperCGF.EmitStmt(FinallyBlock);
204
205
0
        HelperCGF.FinishFunction(FinallyBlock->getEndLoc());
206
207
0
        llvm::Function *FinallyFunc = HelperCGF.CurFn;
208
209
210
        // Push a cleanup for __finally blocks.
211
0
        CGF.pushSEHCleanup(NormalAndEHCleanup, FinallyFunc);
212
0
    }
213
214
215
  // Emit the try body.
216
185
  CGF.EmitStmt(S.getTryBody());
217
218
  // Leave the try.
219
185
  if (S.getNumCatchStmts())
220
181
    CGF.popCatchScope();
221
222
  // Remember where we were.
223
185
  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
224
225
  // Emit the handlers.
226
411
  for (unsigned I = 0, E = Handlers.size(); I != E; 
++I226
) {
227
226
    CatchHandler &Handler = Handlers[I];
228
229
226
    CGF.EmitBlock(Handler.Block);
230
226
    llvm::CatchPadInst *CPI = nullptr;
231
226
    SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(CGF.CurrentFuncletPad);
232
226
    if (useFunclets)
233
23
      if ((CPI = dyn_cast_or_null<llvm::CatchPadInst>(Handler.Block->getFirstNonPHI()))) {
234
14
        CGF.CurrentFuncletPad = CPI;
235
14
        CPI->setOperand(2, CGF.getExceptionSlot().getPointer());
236
14
      }
237
226
    llvm::Value *RawExn = CGF.getExceptionFromSlot();
238
239
    // Enter the catch.
240
226
    llvm::Value *Exn = RawExn;
241
226
    if (beginCatchFn)
242
176
      Exn = CGF.EmitNounwindRuntimeCall(beginCatchFn, RawExn, "exn.adjusted");
243
244
226
    CodeGenFunction::LexicalScope cleanups(CGF, Handler.Body->getSourceRange());
245
246
226
    if (endCatchFn) {
247
      // Add a cleanup to leave the catch.
248
176
      bool EndCatchMightThrow = (Handler.Variable == nullptr);
249
250
176
      CGF.EHStack.pushCleanup<CallObjCEndCatch>(NormalAndEHCleanup,
251
176
                                                EndCatchMightThrow,
252
176
                                                endCatchFn);
253
176
    }
254
255
    // Bind the catch parameter if it exists.
256
226
    if (const VarDecl *CatchParam = Handler.Variable) {
257
183
      llvm::Type *CatchType = CGF.ConvertType(CatchParam->getType());
258
183
      llvm::Value *CastExn = CGF.Builder.CreateBitCast(Exn, CatchType);
259
260
183
      CGF.EmitAutoVarDecl(*CatchParam);
261
183
      EmitInitOfCatchParam(CGF, CastExn, CatchParam);
262
183
    }
263
226
    if (CPI)
264
14
        CGF.EHStack.pushCleanup<CatchRetScope>(NormalCleanup, CPI);
265
266
226
    CGF.ObjCEHValueStack.push_back(Exn);
267
226
    CGF.EmitStmt(Handler.Body);
268
226
    CGF.ObjCEHValueStack.pop_back();
269
270
    // Leave any cleanups associated with the catch.
271
226
    cleanups.ForceCleanup();
272
273
226
    CGF.EmitBranchThroughCleanup(Cont);
274
226
  }
275
276
  // Go back to the try-statement fallthrough.
277
185
  CGF.Builder.restoreIP(SavedIP);
278
279
  // Pop out of the finally.
280
185
  if (!useFunclets && 
S.getFinallyStmt()170
)
281
11
    FinallyInfo.exit(CGF);
282
283
185
  if (Cont.isValid())
284
181
    CGF.EmitBlock(Cont.getBlock());
285
185
}
286
287
void CGObjCRuntime::EmitInitOfCatchParam(CodeGenFunction &CGF,
288
                                         llvm::Value *exn,
289
208
                                         const VarDecl *paramDecl) {
290
291
208
  Address paramAddr = CGF.GetAddrOfLocalVar(paramDecl);
292
293
208
  switch (paramDecl->getType().getQualifiers().getObjCLifetime()) {
294
7
  case Qualifiers::OCL_Strong:
295
7
    exn = CGF.EmitARCRetainNonBlock(exn);
296
7
    LLVM_FALLTHROUGH;
297
298
206
  case Qualifiers::OCL_None:
299
206
  case Qualifiers::OCL_ExplicitNone:
300
206
  case Qualifiers::OCL_Autoreleasing:
301
206
    CGF.Builder.CreateStore(exn, paramAddr);
302
206
    return;
303
304
2
  case Qualifiers::OCL_Weak:
305
2
    CGF.EmitARCInitWeak(paramAddr, exn);
306
2
    return;
307
208
  }
308
0
  llvm_unreachable("invalid ownership qualifier");
309
0
}
310
311
namespace {
312
  struct CallSyncExit final : EHScopeStack::Cleanup {
313
    llvm::FunctionCallee SyncExitFn;
314
    llvm::Value *SyncArg;
315
    CallSyncExit(llvm::FunctionCallee SyncExitFn, llvm::Value *SyncArg)
316
7
        : SyncExitFn(SyncExitFn), SyncArg(SyncArg) {}
317
318
7
    void Emit(CodeGenFunction &CGF, Flags flags) override {
319
7
      CGF.EmitNounwindRuntimeCall(SyncExitFn, SyncArg);
320
7
    }
321
  };
322
}
323
324
void CGObjCRuntime::EmitAtSynchronizedStmt(CodeGenFunction &CGF,
325
                                           const ObjCAtSynchronizedStmt &S,
326
                                           llvm::FunctionCallee syncEnterFn,
327
7
                                           llvm::FunctionCallee syncExitFn) {
328
7
  CodeGenFunction::RunCleanupsScope cleanups(CGF);
329
330
  // Evaluate the lock operand.  This is guaranteed to dominate the
331
  // ARC release and lock-release cleanups.
332
7
  const Expr *lockExpr = S.getSynchExpr();
333
7
  llvm::Value *lock;
334
7
  if (CGF.getLangOpts().ObjCAutoRefCount) {
335
4
    lock = CGF.EmitARCRetainScalarExpr(lockExpr);
336
4
    lock = CGF.EmitObjCConsumeObject(lockExpr->getType(), lock);
337
4
  } else {
338
3
    lock = CGF.EmitScalarExpr(lockExpr);
339
3
  }
340
7
  lock = CGF.Builder.CreateBitCast(lock, CGF.VoidPtrTy);
341
342
  // Acquire the lock.
343
7
  CGF.Builder.CreateCall(syncEnterFn, lock)->setDoesNotThrow();
344
345
  // Register an all-paths cleanup to release the lock.
346
7
  CGF.EHStack.pushCleanup<CallSyncExit>(NormalAndEHCleanup, syncExitFn, lock);
347
348
  // Emit the body of the statement.
349
7
  CGF.EmitStmt(S.getSynchBody());
350
7
}
351
352
/// Compute the pointer-to-function type to which a message send
353
/// should be casted in order to correctly call the given method
354
/// with the given arguments.
355
///
356
/// \param method - may be null
357
/// \param resultType - the result type to use if there's no method
358
/// \param callArgs - the actual arguments, including implicit ones
359
CGObjCRuntime::MessageSendInfo
360
CGObjCRuntime::getMessageSendInfo(const ObjCMethodDecl *method,
361
                                  QualType resultType,
362
11.9k
                                  CallArgList &callArgs) {
363
  // If there's a method, use information from that.
364
11.9k
  if (method) {
365
11.1k
    const CGFunctionInfo &signature =
366
11.1k
      CGM.getTypes().arrangeObjCMessageSendSignature(method, callArgs[0].Ty);
367
368
11.1k
    llvm::PointerType *signatureType =
369
11.1k
      CGM.getTypes().GetFunctionType(signature)->getPointerTo();
370
371
11.1k
    const CGFunctionInfo &signatureForCall =
372
11.1k
      CGM.getTypes().arrangeCall(signature, callArgs);
373
374
11.1k
    return MessageSendInfo(signatureForCall, signatureType);
375
11.1k
  }
376
377
  // There's no method;  just use a default CC.
378
800
  const CGFunctionInfo &argsInfo =
379
800
    CGM.getTypes().arrangeUnprototypedObjCMessageSend(resultType, callArgs);
380
381
  // Derive the signature to call from that.
382
800
  llvm::PointerType *signatureType =
383
800
    CGM.getTypes().GetFunctionType(argsInfo)->getPointerTo();
384
800
  return MessageSendInfo(argsInfo, signatureType);
385
11.9k
}
386
387
bool CGObjCRuntime::canMessageReceiverBeNull(CodeGenFunction &CGF,
388
                                             const ObjCMethodDecl *method,
389
                                             bool isSuper,
390
                                       const ObjCInterfaceDecl *classReceiver,
391
11.9k
                                             llvm::Value *receiver) {
392
  // Super dispatch assumes that self is non-null; even the messenger
393
  // doesn't have a null check internally.
394
11.9k
  if (isSuper)
395
486
    return false;
396
397
  // If this is a direct dispatch of a class method, check whether the class,
398
  // or anything in its hierarchy, was weak-linked.
399
11.4k
  if (classReceiver && 
method4.18k
&&
method->isClassMethod()4.17k
)
400
4.15k
    return isWeakLinkedClass(classReceiver);
401
402
  // If we're emitting a method, and self is const (meaning just ARC, for now),
403
  // and the receiver is a load of self, then self is a valid object.
404
7.26k
  if (auto curMethod =
405
7.26k
               dyn_cast_or_null<ObjCMethodDecl>(CGF.CurCodeDecl)) {
406
404
    auto self = curMethod->getSelfDecl();
407
404
    if (self->getType().isConstQualified()) {
408
33
      if (auto LI = dyn_cast<llvm::LoadInst>(receiver->stripPointerCasts())) {
409
27
        llvm::Value *selfAddr = CGF.GetAddrOfLocalVar(self).getPointer();
410
27
        if (selfAddr == LI->getPointerOperand()) {
411
18
          return false;
412
18
        }
413
27
      }
414
33
    }
415
404
  }
416
417
  // Otherwise, assume it can be null.
418
7.24k
  return true;
419
7.26k
}
420
421
4.15k
bool CGObjCRuntime::isWeakLinkedClass(const ObjCInterfaceDecl *ID) {
422
9.30k
  do {
423
9.30k
    if (ID->isWeakImported())
424
5
      return true;
425
9.30k
  } while (
(ID = ID->getSuperClass())9.30k
);
426
427
4.14k
  return false;
428
4.15k
}
429
430
void CGObjCRuntime::destroyCalleeDestroyedArguments(CodeGenFunction &CGF,
431
                                              const ObjCMethodDecl *method,
432
36
                                              const CallArgList &callArgs) {
433
36
  CallArgList::const_iterator I = callArgs.begin();
434
36
  for (auto i = method->param_begin(), e = method->param_end();
435
63
         i != e; 
++i, ++I27
) {
436
27
    const ParmVarDecl *param = (*i);
437
27
    if (param->hasAttr<NSConsumedAttr>()) {
438
11
      RValue RV = I->getRValue(CGF);
439
11
      assert(RV.isScalar() &&
440
11
             "NullReturnState::complete - arg not on object");
441
0
      CGF.EmitARCRelease(RV.getScalarVal(), ARCImpreciseLifetime);
442
16
    } else {
443
16
      QualType QT = param->getType();
444
16
      auto *RT = QT->getAs<RecordType>();
445
16
      if (RT && RT->getDecl()->isParamDestroyedInCallee()) {
446
16
        RValue RV = I->getRValue(CGF);
447
16
        QualType::DestructionKind DtorKind = QT.isDestructedType();
448
16
        switch (DtorKind) {
449
8
        case QualType::DK_cxx_destructor:
450
8
          CGF.destroyCXXObject(CGF, RV.getAggregateAddress(), QT);
451
8
          break;
452
8
        case QualType::DK_nontrivial_c_struct:
453
8
          CGF.destroyNonTrivialCStruct(CGF, RV.getAggregateAddress(), QT);
454
8
          break;
455
0
        default:
456
0
          llvm_unreachable("unexpected dtor kind");
457
0
          break;
458
16
        }
459
16
      }
460
16
    }
461
27
  }
462
36
}
463
464
llvm::Constant *
465
clang::CodeGen::emitObjCProtocolObject(CodeGenModule &CGM,
466
0
                                       const ObjCProtocolDecl *protocol) {
467
0
  return CGM.getObjCRuntime().GetOrEmitProtocol(protocol);
468
0
}
469
470
std::string CGObjCRuntime::getSymbolNameForMethod(const ObjCMethodDecl *OMD,
471
2.66k
                                                  bool includeCategoryName) {
472
2.66k
  std::string buffer;
473
2.66k
  llvm::raw_string_ostream out(buffer);
474
2.66k
  CGM.getCXXABI().getMangleContext().mangleObjCMethodName(OMD, out,
475
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                                       /*includePrefixByte=*/true,
476
2.66k
                                       includeCategoryName);
477
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  return buffer;
478
2.66k
}