Coverage Report

Created: 2020-09-22 08:39

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/Analysis/BodyFarm.cpp
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Source (jump to first uncovered line)
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//== BodyFarm.cpp  - Factory for conjuring up fake bodies ----------*- C++ -*-//
2
//
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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
6
//
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//===----------------------------------------------------------------------===//
8
//
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// BodyFarm is a factory for creating faux implementations for functions/methods
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// for analysis purposes.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Analysis/BodyFarm.h"
15
#include "clang/AST/ASTContext.h"
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#include "clang/AST/CXXInheritance.h"
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#include "clang/AST/Decl.h"
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#include "clang/AST/Expr.h"
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#include "clang/AST/ExprCXX.h"
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#include "clang/AST/ExprObjC.h"
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#include "clang/AST/NestedNameSpecifier.h"
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#include "clang/Analysis/CodeInjector.h"
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#include "clang/Basic/OperatorKinds.h"
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#include "llvm/ADT/StringSwitch.h"
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#include "llvm/Support/Debug.h"
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#define DEBUG_TYPE "body-farm"
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using namespace clang;
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31
//===----------------------------------------------------------------------===//
32
// Helper creation functions for constructing faux ASTs.
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//===----------------------------------------------------------------------===//
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35
14
static bool isDispatchBlock(QualType Ty) {
36
  // Is it a block pointer?
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14
  const BlockPointerType *BPT = Ty->getAs<BlockPointerType>();
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14
  if (!BPT)
39
0
    return false;
40
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  // Check if the block pointer type takes no arguments and
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  // returns void.
43
14
  const FunctionProtoType *FT =
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14
  BPT->getPointeeType()->getAs<FunctionProtoType>();
45
14
  return FT && FT->getReturnType()->isVoidType() && FT->getNumParams() == 0;
46
14
}
47
48
namespace {
49
class ASTMaker {
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public:
51
199
  ASTMaker(ASTContext &C) : C(C) {}
52
53
  /// Create a new BinaryOperator representing a simple assignment.
54
  BinaryOperator *makeAssignment(const Expr *LHS, const Expr *RHS, QualType Ty);
55
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  /// Create a new BinaryOperator representing a comparison.
57
  BinaryOperator *makeComparison(const Expr *LHS, const Expr *RHS,
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                                 BinaryOperator::Opcode Op);
59
60
  /// Create a new compound stmt using the provided statements.
61
  CompoundStmt *makeCompound(ArrayRef<Stmt*>);
62
63
  /// Create a new DeclRefExpr for the referenced variable.
64
  DeclRefExpr *makeDeclRefExpr(const VarDecl *D,
65
                               bool RefersToEnclosingVariableOrCapture = false);
66
67
  /// Create a new UnaryOperator representing a dereference.
68
  UnaryOperator *makeDereference(const Expr *Arg, QualType Ty);
69
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  /// Create an implicit cast for an integer conversion.
71
  Expr *makeIntegralCast(const Expr *Arg, QualType Ty);
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  /// Create an implicit cast to a builtin boolean type.
74
  ImplicitCastExpr *makeIntegralCastToBoolean(const Expr *Arg);
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  /// Create an implicit cast for lvalue-to-rvaluate conversions.
77
  ImplicitCastExpr *makeLvalueToRvalue(const Expr *Arg, QualType Ty);
78
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  /// Make RValue out of variable declaration, creating a temporary
80
  /// DeclRefExpr in the process.
81
  ImplicitCastExpr *
82
  makeLvalueToRvalue(const VarDecl *Decl,
83
                     bool RefersToEnclosingVariableOrCapture = false);
84
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  /// Create an implicit cast of the given type.
86
  ImplicitCastExpr *makeImplicitCast(const Expr *Arg, QualType Ty,
87
                                     CastKind CK = CK_LValueToRValue);
88
89
  /// Create an Objective-C bool literal.
90
  ObjCBoolLiteralExpr *makeObjCBool(bool Val);
91
92
  /// Create an Objective-C ivar reference.
93
  ObjCIvarRefExpr *makeObjCIvarRef(const Expr *Base, const ObjCIvarDecl *IVar);
94
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  /// Create a Return statement.
96
  ReturnStmt *makeReturn(const Expr *RetVal);
97
98
  /// Create an integer literal expression of the given type.
99
  IntegerLiteral *makeIntegerLiteral(uint64_t Value, QualType Ty);
100
101
  /// Create a member expression.
102
  MemberExpr *makeMemberExpression(Expr *base, ValueDecl *MemberDecl,
103
                                   bool IsArrow = false,
104
                                   ExprValueKind ValueKind = VK_LValue);
105
106
  /// Returns a *first* member field of a record declaration with a given name.
107
  /// \return an nullptr if no member with such a name exists.
108
  ValueDecl *findMemberField(const RecordDecl *RD, StringRef Name);
109
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private:
111
  ASTContext &C;
112
};
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}
114
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BinaryOperator *ASTMaker::makeAssignment(const Expr *LHS, const Expr *RHS,
116
77
                                         QualType Ty) {
117
77
  return BinaryOperator::Create(
118
77
      C, const_cast<Expr *>(LHS), const_cast<Expr *>(RHS), BO_Assign, Ty,
119
77
      VK_RValue, OK_Ordinary, SourceLocation(), FPOptionsOverride());
120
77
}
121
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BinaryOperator *ASTMaker::makeComparison(const Expr *LHS, const Expr *RHS,
123
30
                                         BinaryOperator::Opcode Op) {
124
30
  assert(BinaryOperator::isLogicalOp(Op) ||
125
30
         BinaryOperator::isComparisonOp(Op));
126
30
  return BinaryOperator::Create(
127
30
      C, const_cast<Expr *>(LHS), const_cast<Expr *>(RHS), Op,
128
30
      C.getLogicalOperationType(), VK_RValue, OK_Ordinary, SourceLocation(),
129
30
      FPOptionsOverride());
130
30
}
131
132
77
CompoundStmt *ASTMaker::makeCompound(ArrayRef<Stmt *> Stmts) {
133
77
  return CompoundStmt::Create(C, Stmts, SourceLocation(), SourceLocation());
134
77
}
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DeclRefExpr *ASTMaker::makeDeclRefExpr(
137
    const VarDecl *D,
138
303
    bool RefersToEnclosingVariableOrCapture) {
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303
  QualType Type = D->getType().getNonReferenceType();
140
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303
  DeclRefExpr *DR = DeclRefExpr::Create(
142
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      C, NestedNameSpecifierLoc(), SourceLocation(), const_cast<VarDecl *>(D),
143
303
      RefersToEnclosingVariableOrCapture, SourceLocation(), Type, VK_LValue);
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  return DR;
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}
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60
UnaryOperator *ASTMaker::makeDereference(const Expr *Arg, QualType Ty) {
148
60
  return UnaryOperator::Create(C, const_cast<Expr *>(Arg), UO_Deref, Ty,
149
60
                               VK_LValue, OK_Ordinary, SourceLocation(),
150
60
                               /*CanOverflow*/ false, FPOptionsOverride());
151
60
}
152
153
332
ImplicitCastExpr *ASTMaker::makeLvalueToRvalue(const Expr *Arg, QualType Ty) {
154
332
  return makeImplicitCast(Arg, Ty, CK_LValueToRValue);
155
332
}
156
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ImplicitCastExpr *
158
ASTMaker::makeLvalueToRvalue(const VarDecl *Arg,
159
10
                             bool RefersToEnclosingVariableOrCapture) {
160
10
  QualType Type = Arg->getType().getNonReferenceType();
161
10
  return makeLvalueToRvalue(makeDeclRefExpr(Arg,
162
10
                                            RefersToEnclosingVariableOrCapture),
163
10
                            Type);
164
10
}
165
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ImplicitCastExpr *ASTMaker::makeImplicitCast(const Expr *Arg, QualType Ty,
167
465
                                             CastKind CK) {
168
465
  return ImplicitCastExpr::Create(C, Ty,
169
465
                                  /* CastKind=*/CK,
170
465
                                  /* Expr=*/const_cast<Expr *>(Arg),
171
465
                                  /* CXXCastPath=*/nullptr,
172
465
                                  /* ExprValueKind=*/VK_RValue,
173
465
                                  /* FPFeatures */ FPOptionsOverride());
174
465
}
175
176
71
Expr *ASTMaker::makeIntegralCast(const Expr *Arg, QualType Ty) {
177
71
  if (Arg->getType() == Ty)
178
24
    return const_cast<Expr*>(Arg);
179
47
  return makeImplicitCast(Arg, Ty, CK_IntegralCast);
180
47
}
181
182
26
ImplicitCastExpr *ASTMaker::makeIntegralCastToBoolean(const Expr *Arg) {
183
26
  return makeImplicitCast(Arg, C.BoolTy, CK_IntegralToBoolean);
184
26
}
185
186
40
ObjCBoolLiteralExpr *ASTMaker::makeObjCBool(bool Val) {
187
40
  QualType Ty = C.getBOOLDecl() ? 
C.getBOOLType()0
: C.ObjCBuiltinBoolTy;
188
40
  return new (C) ObjCBoolLiteralExpr(Val, Ty, SourceLocation());
189
40
}
190
191
ObjCIvarRefExpr *ASTMaker::makeObjCIvarRef(const Expr *Base,
192
56
                                           const ObjCIvarDecl *IVar) {
193
56
  return new (C) ObjCIvarRefExpr(const_cast<ObjCIvarDecl*>(IVar),
194
56
                                 IVar->getType(), SourceLocation(),
195
56
                                 SourceLocation(), const_cast<Expr*>(Base),
196
56
                                 /*arrow=*/true, /*free=*/false);
197
56
}
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199
100
ReturnStmt *ASTMaker::makeReturn(const Expr *RetVal) {
200
100
  return ReturnStmt::Create(C, SourceLocation(), const_cast<Expr *>(RetVal),
201
100
                            /* NRVOCandidate=*/nullptr);
202
100
}
203
204
57
IntegerLiteral *ASTMaker::makeIntegerLiteral(uint64_t Value, QualType Ty) {
205
57
  llvm::APInt APValue = llvm::APInt(C.getTypeSize(Ty), Value);
206
57
  return IntegerLiteral::Create(C, APValue, Ty, SourceLocation());
207
57
}
208
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MemberExpr *ASTMaker::makeMemberExpression(Expr *base, ValueDecl *MemberDecl,
210
                                           bool IsArrow,
211
47
                                           ExprValueKind ValueKind) {
212
213
47
  DeclAccessPair FoundDecl = DeclAccessPair::make(MemberDecl, AS_public);
214
47
  return MemberExpr::Create(
215
47
      C, base, IsArrow, SourceLocation(), NestedNameSpecifierLoc(),
216
47
      SourceLocation(), MemberDecl, FoundDecl,
217
47
      DeclarationNameInfo(MemberDecl->getDeclName(), SourceLocation()),
218
47
      /* TemplateArgumentListInfo=*/ nullptr, MemberDecl->getType(), ValueKind,
219
47
      OK_Ordinary, NOUR_None);
220
47
}
221
222
80
ValueDecl *ASTMaker::findMemberField(const RecordDecl *RD, StringRef Name) {
223
224
80
  CXXBasePaths Paths(
225
80
      /* FindAmbiguities=*/false,
226
80
      /* RecordPaths=*/false,
227
80
      /* DetectVirtual=*/ false);
228
80
  const IdentifierInfo &II = C.Idents.get(Name);
229
80
  DeclarationName DeclName = C.DeclarationNames.getIdentifier(&II);
230
231
80
  DeclContextLookupResult Decls = RD->lookup(DeclName);
232
80
  for (NamedDecl *FoundDecl : Decls)
233
53
    if (!FoundDecl->getDeclContext()->isFunctionOrMethod())
234
53
      return cast<ValueDecl>(FoundDecl);
235
236
27
  return nullptr;
237
80
}
238
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//===----------------------------------------------------------------------===//
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// Creation functions for faux ASTs.
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//===----------------------------------------------------------------------===//
242
243
typedef Stmt *(*FunctionFarmer)(ASTContext &C, const FunctionDecl *D);
244
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static CallExpr *create_call_once_funcptr_call(ASTContext &C, ASTMaker M,
246
                                               const ParmVarDecl *Callback,
247
15
                                               ArrayRef<Expr *> CallArgs) {
248
249
15
  QualType Ty = Callback->getType();
250
15
  DeclRefExpr *Call = M.makeDeclRefExpr(Callback);
251
15
  Expr *SubExpr;
252
15
  if (Ty->isRValueReferenceType()) {
253
11
    SubExpr = M.makeImplicitCast(
254
11
        Call, Ty.getNonReferenceType(), CK_LValueToRValue);
255
4
  } else if (Ty->isLValueReferenceType() &&
256
4
             Call->getType()->isFunctionType()) {
257
2
    Ty = C.getPointerType(Ty.getNonReferenceType());
258
2
    SubExpr = M.makeImplicitCast(Call, Ty, CK_FunctionToPointerDecay);
259
2
  } else if (Ty->isLValueReferenceType()
260
2
             && Call->getType()->isPointerType()
261
2
             && Call->getType()->getPointeeType()->isFunctionType()){
262
2
    SubExpr = Call;
263
0
  } else {
264
0
    llvm_unreachable("Unexpected state");
265
0
  }
266
267
15
  return CallExpr::Create(C, SubExpr, CallArgs, C.VoidTy, VK_RValue,
268
15
                          SourceLocation(), FPOptionsOverride());
269
15
}
270
271
static CallExpr *create_call_once_lambda_call(ASTContext &C, ASTMaker M,
272
                                              const ParmVarDecl *Callback,
273
                                              CXXRecordDecl *CallbackDecl,
274
32
                                              ArrayRef<Expr *> CallArgs) {
275
32
  assert(CallbackDecl != nullptr);
276
32
  assert(CallbackDecl->isLambda());
277
32
  FunctionDecl *callOperatorDecl = CallbackDecl->getLambdaCallOperator();
278
32
  assert(callOperatorDecl != nullptr);
279
280
32
  DeclRefExpr *callOperatorDeclRef =
281
32
      DeclRefExpr::Create(/* Ctx =*/ C,
282
32
                          /* QualifierLoc =*/ NestedNameSpecifierLoc(),
283
32
                          /* TemplateKWLoc =*/ SourceLocation(),
284
32
                          const_cast<FunctionDecl *>(callOperatorDecl),
285
32
                          /* RefersToEnclosingVariableOrCapture=*/ false,
286
32
                          /* NameLoc =*/ SourceLocation(),
287
32
                          /* T =*/ callOperatorDecl->getType(),
288
32
                          /* VK =*/ VK_LValue);
289
290
32
  return CXXOperatorCallExpr::Create(
291
32
      /*AstContext=*/C, OO_Call, callOperatorDeclRef,
292
32
      /*Args=*/CallArgs,
293
32
      /*QualType=*/C.VoidTy,
294
32
      /*ExprValueType=*/VK_RValue,
295
32
      /*SourceLocation=*/SourceLocation(),
296
32
      /*FPFeatures=*/FPOptionsOverride());
297
32
}
298
299
/// Create a fake body for std::call_once.
300
/// Emulates the following function body:
301
///
302
/// \code
303
/// typedef struct once_flag_s {
304
///   unsigned long __state = 0;
305
/// } once_flag;
306
/// template<class Callable>
307
/// void call_once(once_flag& o, Callable func) {
308
///   if (!o.__state) {
309
///     func();
310
///   }
311
///   o.__state = 1;
312
/// }
313
/// \endcode
314
105
static Stmt *create_call_once(ASTContext &C, const FunctionDecl *D) {
315
105
  LLVM_DEBUG(llvm::dbgs() << "Generating body for call_once\n");
316
317
  // We need at least two parameters.
318
105
  if (D->param_size() < 2)
319
0
    return nullptr;
320
321
105
  ASTMaker M(C);
322
323
105
  const ParmVarDecl *Flag = D->getParamDecl(0);
324
105
  const ParmVarDecl *Callback = D->getParamDecl(1);
325
326
105
  if (!Callback->getType()->isReferenceType()) {
327
52
    llvm::dbgs() << "libcxx03 std::call_once implementation, skipping.\n";
328
52
    return nullptr;
329
52
  }
330
53
  if (!Flag->getType()->isReferenceType()) {
331
0
    llvm::dbgs() << "unknown std::call_once implementation, skipping.\n";
332
0
    return nullptr;
333
0
  }
334
335
53
  QualType CallbackType = Callback->getType().getNonReferenceType();
336
337
  // Nullable pointer, non-null iff function is a CXXRecordDecl.
338
53
  CXXRecordDecl *CallbackRecordDecl = CallbackType->getAsCXXRecordDecl();
339
53
  QualType FlagType = Flag->getType().getNonReferenceType();
340
53
  auto *FlagRecordDecl = FlagType->getAsRecordDecl();
341
342
53
  if (!FlagRecordDecl) {
343
0
    LLVM_DEBUG(llvm::dbgs() << "Flag field is not a record: "
344
0
                            << "unknown std::call_once implementation, "
345
0
                            << "ignoring the call.\n");
346
0
    return nullptr;
347
0
  }
348
349
  // We initially assume libc++ implementation of call_once,
350
  // where the once_flag struct has a field `__state_`.
351
53
  ValueDecl *FlagFieldDecl = M.findMemberField(FlagRecordDecl, "__state_");
352
353
  // Otherwise, try libstdc++ implementation, with a field
354
  // `_M_once`
355
53
  if (!FlagFieldDecl) {
356
27
    FlagFieldDecl = M.findMemberField(FlagRecordDecl, "_M_once");
357
27
  }
358
359
53
  if (!FlagFieldDecl) {
360
0
    LLVM_DEBUG(llvm::dbgs() << "No field _M_once or __state_ found on "
361
0
                            << "std::once_flag struct: unknown std::call_once "
362
0
                            << "implementation, ignoring the call.");
363
0
    return nullptr;
364
0
  }
365
366
53
  bool isLambdaCall = CallbackRecordDecl && 
CallbackRecordDecl->isLambda()34
;
367
53
  if (CallbackRecordDecl && 
!isLambdaCall34
) {
368
2
    LLVM_DEBUG(llvm::dbgs()
369
2
               << "Not supported: synthesizing body for functors when "
370
2
               << "body farming std::call_once, ignoring the call.");
371
2
    return nullptr;
372
2
  }
373
374
51
  SmallVector<Expr *, 5> CallArgs;
375
51
  const FunctionProtoType *CallbackFunctionType;
376
51
  if (isLambdaCall) {
377
378
    // Lambda requires callback itself inserted as a first parameter.
379
32
    CallArgs.push_back(
380
32
        M.makeDeclRefExpr(Callback,
381
32
                          /* RefersToEnclosingVariableOrCapture=*/ true));
382
32
    CallbackFunctionType = CallbackRecordDecl->getLambdaCallOperator()
383
32
                               ->getType()
384
32
                               ->getAs<FunctionProtoType>();
385
19
  } else if (!CallbackType->getPointeeType().isNull()) {
386
13
    CallbackFunctionType =
387
13
        CallbackType->getPointeeType()->getAs<FunctionProtoType>();
388
6
  } else {
389
6
    CallbackFunctionType = CallbackType->getAs<FunctionProtoType>();
390
6
  }
391
392
51
  if (!CallbackFunctionType)
393
0
    return nullptr;
394
395
  // First two arguments are used for the flag and for the callback.
396
51
  if (D->getNumParams() != CallbackFunctionType->getNumParams() + 2) {
397
0
    LLVM_DEBUG(llvm::dbgs() << "Types of params of the callback do not match "
398
0
                            << "params passed to std::call_once, "
399
0
                            << "ignoring the call\n");
400
0
    return nullptr;
401
0
  }
402
403
  // All arguments past first two ones are passed to the callback,
404
  // and we turn lvalues into rvalues if the argument is not passed by
405
  // reference.
406
90
  
for (unsigned int ParamIdx = 2; 51
ParamIdx < D->getNumParams();
ParamIdx++39
) {
407
43
    const ParmVarDecl *PDecl = D->getParamDecl(ParamIdx);
408
43
    assert(PDecl);
409
43
    if (CallbackFunctionType->getParamType(ParamIdx - 2)
410
43
                .getNonReferenceType()
411
43
                .getCanonicalType() !=
412
4
            PDecl->getType().getNonReferenceType().getCanonicalType()) {
413
4
      LLVM_DEBUG(llvm::dbgs() << "Types of params of the callback do not match "
414
4
                              << "params passed to std::call_once, "
415
4
                              << "ignoring the call\n");
416
4
      return nullptr;
417
4
    }
418
39
    Expr *ParamExpr = M.makeDeclRefExpr(PDecl);
419
39
    if (!CallbackFunctionType->getParamType(ParamIdx - 2)->isReferenceType()) {
420
31
      QualType PTy = PDecl->getType().getNonReferenceType();
421
31
      ParamExpr = M.makeLvalueToRvalue(ParamExpr, PTy);
422
31
    }
423
39
    CallArgs.push_back(ParamExpr);
424
39
  }
425
426
47
  CallExpr *CallbackCall;
427
47
  if (isLambdaCall) {
428
429
32
    CallbackCall = create_call_once_lambda_call(C, M, Callback,
430
32
                                                CallbackRecordDecl, CallArgs);
431
15
  } else {
432
433
    // Function pointer case.
434
15
    CallbackCall = create_call_once_funcptr_call(C, M, Callback, CallArgs);
435
15
  }
436
437
47
  DeclRefExpr *FlagDecl =
438
47
      M.makeDeclRefExpr(Flag,
439
47
                        /* RefersToEnclosingVariableOrCapture=*/true);
440
441
442
47
  MemberExpr *Deref = M.makeMemberExpression(FlagDecl, FlagFieldDecl);
443
47
  assert(Deref->isLValue());
444
47
  QualType DerefType = Deref->getType();
445
446
  // Negation predicate.
447
47
  UnaryOperator *FlagCheck = UnaryOperator::Create(
448
47
      C,
449
      /* input=*/
450
47
      M.makeImplicitCast(M.makeLvalueToRvalue(Deref, DerefType), DerefType,
451
47
                         CK_IntegralToBoolean),
452
47
      /* opc=*/UO_LNot,
453
47
      /* QualType=*/C.IntTy,
454
47
      /* ExprValueKind=*/VK_RValue,
455
47
      /* ExprObjectKind=*/OK_Ordinary, SourceLocation(),
456
47
      /* CanOverflow*/ false, FPOptionsOverride());
457
458
  // Create assignment.
459
47
  BinaryOperator *FlagAssignment = M.makeAssignment(
460
47
      Deref, M.makeIntegralCast(M.makeIntegerLiteral(1, C.IntTy), DerefType),
461
47
      DerefType);
462
463
47
  auto *Out =
464
47
      IfStmt::Create(C, SourceLocation(),
465
47
                     /* IsConstexpr=*/false,
466
47
                     /* Init=*/nullptr,
467
47
                     /* Var=*/nullptr,
468
47
                     /* Cond=*/FlagCheck,
469
47
                     /* LPL=*/SourceLocation(),
470
47
                     /* RPL=*/SourceLocation(),
471
47
                     /* Then=*/M.makeCompound({CallbackCall, FlagAssignment}));
472
473
47
  return Out;
474
51
}
475
476
/// Create a fake body for dispatch_once.
477
10
static Stmt *create_dispatch_once(ASTContext &C, const FunctionDecl *D) {
478
  // Check if we have at least two parameters.
479
10
  if (D->param_size() != 2)
480
0
    return nullptr;
481
482
  // Check if the first parameter is a pointer to integer type.
483
10
  const ParmVarDecl *Predicate = D->getParamDecl(0);
484
10
  QualType PredicateQPtrTy = Predicate->getType();
485
10
  const PointerType *PredicatePtrTy = PredicateQPtrTy->getAs<PointerType>();
486
10
  if (!PredicatePtrTy)
487
0
    return nullptr;
488
10
  QualType PredicateTy = PredicatePtrTy->getPointeeType();
489
10
  if (!PredicateTy->isIntegerType())
490
0
    return nullptr;
491
492
  // Check if the second parameter is the proper block type.
493
10
  const ParmVarDecl *Block = D->getParamDecl(1);
494
10
  QualType Ty = Block->getType();
495
10
  if (!isDispatchBlock(Ty))
496
0
    return nullptr;
497
498
  // Everything checks out.  Create a fakse body that checks the predicate,
499
  // sets it, and calls the block.  Basically, an AST dump of:
500
  //
501
  // void dispatch_once(dispatch_once_t *predicate, dispatch_block_t block) {
502
  //  if (*predicate != ~0l) {
503
  //    *predicate = ~0l;
504
  //    block();
505
  //  }
506
  // }
507
508
10
  ASTMaker M(C);
509
510
  // (1) Create the call.
511
10
  CallExpr *CE = CallExpr::Create(
512
10
      /*ASTContext=*/C,
513
10
      /*StmtClass=*/M.makeLvalueToRvalue(/*Expr=*/Block),
514
10
      /*Args=*/None,
515
10
      /*QualType=*/C.VoidTy,
516
10
      /*ExprValueType=*/VK_RValue,
517
10
      /*SourceLocation=*/SourceLocation(), FPOptionsOverride());
518
519
  // (2) Create the assignment to the predicate.
520
10
  Expr *DoneValue =
521
10
      UnaryOperator::Create(C, M.makeIntegerLiteral(0, C.LongTy), UO_Not,
522
10
                            C.LongTy, VK_RValue, OK_Ordinary, SourceLocation(),
523
10
                            /*CanOverflow*/ false, FPOptionsOverride());
524
525
10
  BinaryOperator *B =
526
10
    M.makeAssignment(
527
10
       M.makeDereference(
528
10
          M.makeLvalueToRvalue(
529
10
            M.makeDeclRefExpr(Predicate), PredicateQPtrTy),
530
10
            PredicateTy),
531
10
       M.makeIntegralCast(DoneValue, PredicateTy),
532
10
       PredicateTy);
533
534
  // (3) Create the compound statement.
535
10
  Stmt *Stmts[] = { B, CE };
536
10
  CompoundStmt *CS = M.makeCompound(Stmts);
537
538
  // (4) Create the 'if' condition.
539
10
  ImplicitCastExpr *LValToRval =
540
10
    M.makeLvalueToRvalue(
541
10
      M.makeDereference(
542
10
        M.makeLvalueToRvalue(
543
10
          M.makeDeclRefExpr(Predicate),
544
10
          PredicateQPtrTy),
545
10
        PredicateTy),
546
10
    PredicateTy);
547
548
10
  Expr *GuardCondition = M.makeComparison(LValToRval, DoneValue, BO_NE);
549
  // (5) Create the 'if' statement.
550
10
  auto *If = IfStmt::Create(C, SourceLocation(),
551
10
                            /* IsConstexpr=*/false,
552
10
                            /* Init=*/nullptr,
553
10
                            /* Var=*/nullptr,
554
10
                            /* Cond=*/GuardCondition,
555
10
                            /* LPL=*/SourceLocation(),
556
10
                            /* RPL=*/SourceLocation(),
557
10
                            /* Then=*/CS);
558
10
  return If;
559
10
}
560
561
/// Create a fake body for dispatch_sync.
562
4
static Stmt *create_dispatch_sync(ASTContext &C, const FunctionDecl *D) {
563
  // Check if we have at least two parameters.
564
4
  if (D->param_size() != 2)
565
0
    return nullptr;
566
567
  // Check if the second parameter is a block.
568
4
  const ParmVarDecl *PV = D->getParamDecl(1);
569
4
  QualType Ty = PV->getType();
570
4
  if (!isDispatchBlock(Ty))
571
0
    return nullptr;
572
573
  // Everything checks out.  Create a fake body that just calls the block.
574
  // This is basically just an AST dump of:
575
  //
576
  // void dispatch_sync(dispatch_queue_t queue, void (^block)(void)) {
577
  //   block();
578
  // }
579
  //
580
4
  ASTMaker M(C);
581
4
  DeclRefExpr *DR = M.makeDeclRefExpr(PV);
582
4
  ImplicitCastExpr *ICE = M.makeLvalueToRvalue(DR, Ty);
583
4
  CallExpr *CE = CallExpr::Create(C, ICE, None, C.VoidTy, VK_RValue,
584
4
                                  SourceLocation(), FPOptionsOverride());
585
4
  return CE;
586
4
}
587
588
static Stmt *create_OSAtomicCompareAndSwap(ASTContext &C, const FunctionDecl *D)
589
22
{
590
  // There are exactly 3 arguments.
591
22
  if (D->param_size() != 3)
592
2
    return nullptr;
593
594
  // Signature:
595
  // _Bool OSAtomicCompareAndSwapPtr(void *__oldValue,
596
  //                                 void *__newValue,
597
  //                                 void * volatile *__theValue)
598
  // Generate body:
599
  //   if (oldValue == *theValue) {
600
  //    *theValue = newValue;
601
  //    return YES;
602
  //   }
603
  //   else return NO;
604
605
20
  QualType ResultTy = D->getReturnType();
606
20
  bool isBoolean = ResultTy->isBooleanType();
607
20
  if (!isBoolean && 
!ResultTy->isIntegralType(C)7
)
608
0
    return nullptr;
609
610
20
  const ParmVarDecl *OldValue = D->getParamDecl(0);
611
20
  QualType OldValueTy = OldValue->getType();
612
613
20
  const ParmVarDecl *NewValue = D->getParamDecl(1);
614
20
  QualType NewValueTy = NewValue->getType();
615
616
20
  assert(OldValueTy == NewValueTy);
617
618
20
  const ParmVarDecl *TheValue = D->getParamDecl(2);
619
20
  QualType TheValueTy = TheValue->getType();
620
20
  const PointerType *PT = TheValueTy->getAs<PointerType>();
621
20
  if (!PT)
622
0
    return nullptr;
623
20
  QualType PointeeTy = PT->getPointeeType();
624
625
20
  ASTMaker M(C);
626
  // Construct the comparison.
627
20
  Expr *Comparison =
628
20
    M.makeComparison(
629
20
      M.makeLvalueToRvalue(M.makeDeclRefExpr(OldValue), OldValueTy),
630
20
      M.makeLvalueToRvalue(
631
20
        M.makeDereference(
632
20
          M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy),
633
20
          PointeeTy),
634
20
        PointeeTy),
635
20
      BO_EQ);
636
637
  // Construct the body of the IfStmt.
638
20
  Stmt *Stmts[2];
639
20
  Stmts[0] =
640
20
    M.makeAssignment(
641
20
      M.makeDereference(
642
20
        M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy),
643
20
        PointeeTy),
644
20
      M.makeLvalueToRvalue(M.makeDeclRefExpr(NewValue), NewValueTy),
645
20
      NewValueTy);
646
647
20
  Expr *BoolVal = M.makeObjCBool(true);
648
13
  Expr *RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal)
649
7
                           : M.makeIntegralCast(BoolVal, ResultTy);
650
20
  Stmts[1] = M.makeReturn(RetVal);
651
20
  CompoundStmt *Body = M.makeCompound(Stmts);
652
653
  // Construct the else clause.
654
20
  BoolVal = M.makeObjCBool(false);
655
13
  RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal)
656
7
                     : M.makeIntegralCast(BoolVal, ResultTy);
657
20
  Stmt *Else = M.makeReturn(RetVal);
658
659
  /// Construct the If.
660
20
  auto *If =
661
20
      IfStmt::Create(C, SourceLocation(),
662
20
                     /* IsConstexpr=*/false,
663
20
                     /* Init=*/nullptr,
664
20
                     /* Var=*/nullptr, Comparison,
665
20
                     /* LPL=*/SourceLocation(),
666
20
                     /* RPL=*/SourceLocation(), Body, SourceLocation(), Else);
667
668
20
  return If;
669
20
}
670
671
3.67M
Stmt *BodyFarm::getBody(const FunctionDecl *D) {
672
3.67M
  Optional<Stmt *> &Val = Bodies[D];
673
3.67M
  if (Val.hasValue())
674
3.65M
    return Val.getValue();
675
676
22.6k
  Val = nullptr;
677
678
22.6k
  if (D->getIdentifier() == nullptr)
679
5.28k
    return nullptr;
680
681
17.3k
  StringRef Name = D->getName();
682
17.3k
  if (Name.empty())
683
0
    return nullptr;
684
685
17.3k
  FunctionFarmer FF;
686
687
17.3k
  if (Name.startswith("OSAtomicCompareAndSwap") ||
688
17.3k
      Name.startswith("objc_atomicCompareAndSwap")) {
689
22
    FF = create_OSAtomicCompareAndSwap;
690
17.3k
  } else if (Name == "call_once" && 
D->getDeclContext()->isStdNamespace()109
) {
691
105
    FF = create_call_once;
692
17.2k
  } else {
693
17.2k
    FF = llvm::StringSwitch<FunctionFarmer>(Name)
694
17.2k
          .Case("dispatch_sync", create_dispatch_sync)
695
17.2k
          .Case("dispatch_once", create_dispatch_once)
696
17.2k
          .Default(nullptr);
697
17.2k
  }
698
699
17.3k
  if (FF) 
{ Val = FF(C, D); }141
700
17.2k
  else if (Injector) { Val = Injector->getBody(D); }
701
17.3k
  return Val.getValue();
702
17.3k
}
703
704
74
static const ObjCIvarDecl *findBackingIvar(const ObjCPropertyDecl *Prop) {
705
74
  const ObjCIvarDecl *IVar = Prop->getPropertyIvarDecl();
706
707
74
  if (IVar)
708
51
    return IVar;
709
710
  // When a readonly property is shadowed in a class extensions with a
711
  // a readwrite property, the instance variable belongs to the shadowing
712
  // property rather than the shadowed property. If there is no instance
713
  // variable on a readonly property, check to see whether the property is
714
  // shadowed and if so try to get the instance variable from shadowing
715
  // property.
716
23
  if (!Prop->isReadOnly())
717
11
    return nullptr;
718
719
12
  auto *Container = cast<ObjCContainerDecl>(Prop->getDeclContext());
720
12
  const ObjCInterfaceDecl *PrimaryInterface = nullptr;
721
12
  if (auto *InterfaceDecl = dyn_cast<ObjCInterfaceDecl>(Container)) {
722
12
    PrimaryInterface = InterfaceDecl;
723
0
  } else if (auto *CategoryDecl = dyn_cast<ObjCCategoryDecl>(Container)) {
724
0
    PrimaryInterface = CategoryDecl->getClassInterface();
725
0
  } else if (auto *ImplDecl = dyn_cast<ObjCImplDecl>(Container)) {
726
0
    PrimaryInterface = ImplDecl->getClassInterface();
727
0
  } else {
728
0
    return nullptr;
729
0
  }
730
731
  // FindPropertyVisibleInPrimaryClass() looks first in class extensions, so it
732
  // is guaranteed to find the shadowing property, if it exists, rather than
733
  // the shadowed property.
734
12
  auto *ShadowingProp = PrimaryInterface->FindPropertyVisibleInPrimaryClass(
735
12
      Prop->getIdentifier(), Prop->getQueryKind());
736
12
  if (ShadowingProp && ShadowingProp != Prop) {
737
3
    IVar = ShadowingProp->getPropertyIvarDecl();
738
3
  }
739
740
12
  return IVar;
741
12
}
742
743
static Stmt *createObjCPropertyGetter(ASTContext &Ctx,
744
80
                                      const ObjCMethodDecl *MD) {
745
    // First, find the backing ivar.
746
80
  const ObjCIvarDecl *IVar = nullptr;
747
748
  // Property accessor stubs sometimes do not correspond to any property decl
749
  // in the current interface (but in a superclass). They still have a
750
  // corresponding property impl decl in this case.
751
80
  if (MD->isSynthesizedAccessorStub()) {
752
6
    const ObjCInterfaceDecl *IntD = MD->getClassInterface();
753
6
    const ObjCImplementationDecl *ImpD = IntD->getImplementation();
754
10
    for (const auto *PI: ImpD->property_impls()) {
755
10
      if (const ObjCPropertyDecl *P = PI->getPropertyDecl()) {
756
10
        if (P->getGetterName() == MD->getSelector())
757
6
          IVar = P->getPropertyIvarDecl();
758
10
      }
759
10
    }
760
6
  }
761
762
80
  if (!IVar) {
763
74
    const ObjCPropertyDecl *Prop = MD->findPropertyDecl();
764
74
    IVar = findBackingIvar(Prop);
765
74
    if (!IVar)
766
20
      return nullptr;
767
768
    // Ignore weak variables, which have special behavior.
769
54
    if (Prop->getPropertyAttributes() & ObjCPropertyAttribute::kind_weak)
770
0
      return nullptr;
771
772
    // Look to see if Sema has synthesized a body for us. This happens in
773
    // Objective-C++ because the return value may be a C++ class type with a
774
    // non-trivial copy constructor. We can only do this if we can find the
775
    // @synthesize for this property, though (or if we know it's been auto-
776
    // synthesized).
777
54
    const ObjCImplementationDecl *ImplDecl =
778
54
      IVar->getContainingInterface()->getImplementation();
779
54
    if (ImplDecl) {
780
208
      for (const auto *I : ImplDecl->property_impls()) {
781
208
        if (I->getPropertyDecl() != Prop)
782
157
          continue;
783
784
51
        if (I->getGetterCXXConstructor()) {
785
4
          ASTMaker M(Ctx);
786
4
          return M.makeReturn(I->getGetterCXXConstructor());
787
4
        }
788
51
      }
789
54
    }
790
791
    // Sanity check that the property is the same type as the ivar, or a
792
    // reference to it, and that it is either an object pointer or trivially
793
    // copyable.
794
50
    if (!Ctx.hasSameUnqualifiedType(IVar->getType(),
795
50
                                    Prop->getType().getNonReferenceType()))
796
0
      return nullptr;
797
50
    if (!IVar->getType()->isObjCLifetimeType() &&
798
27
        !IVar->getType().isTriviallyCopyableType(Ctx))
799
0
      return nullptr;
800
56
  }
801
802
  // Generate our body:
803
  //   return self->_ivar;
804
56
  ASTMaker M(Ctx);
805
806
56
  const VarDecl *selfVar = MD->getSelfDecl();
807
56
  if (!selfVar)
808
0
    return nullptr;
809
810
56
  Expr *loadedIVar =
811
56
    M.makeObjCIvarRef(
812
56
      M.makeLvalueToRvalue(
813
56
        M.makeDeclRefExpr(selfVar),
814
56
        selfVar->getType()),
815
56
      IVar);
816
817
56
  if (!MD->getReturnType()->isReferenceType())
818
54
    loadedIVar = M.makeLvalueToRvalue(loadedIVar, IVar->getType());
819
820
56
  return M.makeReturn(loadedIVar);
821
56
}
822
823
95.9k
Stmt *BodyFarm::getBody(const ObjCMethodDecl *D) {
824
  // We currently only know how to synthesize property accessors.
825
95.9k
  if (!D->isPropertyAccessor())
826
75.9k
    return nullptr;
827
828
20.0k
  D = D->getCanonicalDecl();
829
830
  // We should not try to synthesize explicitly redefined accessors.
831
  // We do not know for sure how they behave.
832
20.0k
  if (!D->isImplicit())
833
12
    return nullptr;
834
835
20.0k
  Optional<Stmt *> &Val = Bodies[D];
836
20.0k
  if (Val.hasValue())
837
19.9k
    return Val.getValue();
838
129
  Val = nullptr;
839
840
  // For now, we only synthesize getters.
841
  // Synthesizing setters would cause false negatives in the
842
  // RetainCountChecker because the method body would bind the parameter
843
  // to an instance variable, causing it to escape. This would prevent
844
  // warning in the following common scenario:
845
  //
846
  //  id foo = [[NSObject alloc] init];
847
  //  self.foo = foo; // We should warn that foo leaks here.
848
  //
849
129
  if (D->param_size() != 0)
850
49
    return nullptr;
851
852
  // If the property was defined in an extension, search the extensions for
853
  // overrides.
854
80
  const ObjCInterfaceDecl *OID = D->getClassInterface();
855
80
  if (dyn_cast<ObjCInterfaceDecl>(D->getParent()) != OID)
856
18
    
for (auto *Ext : OID->known_extensions())16
{
857
18
      auto *OMD = Ext->getInstanceMethod(D->getSelector());
858
18
      if (OMD && 
!OMD->isImplicit()10
)
859
0
        return nullptr;
860
18
    }
861
862
80
  Val = createObjCPropertyGetter(C, D);
863
864
80
  return Val.getValue();
865
80
}