clang  8.0.0svn
BodyFarm.cpp
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1 //== BodyFarm.cpp - Factory for conjuring up fake bodies ----------*- C++ -*-//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // BodyFarm is a factory for creating faux implementations for functions/methods
11 // for analysis purposes.
12 //
13 //===----------------------------------------------------------------------===//
14 
16 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/Decl.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/ExprCXX.h"
21 #include "clang/AST/ExprObjC.h"
25 #include "llvm/ADT/StringSwitch.h"
26 #include "llvm/Support/Debug.h"
27 
28 #define DEBUG_TYPE "body-farm"
29 
30 using namespace clang;
31 
32 //===----------------------------------------------------------------------===//
33 // Helper creation functions for constructing faux ASTs.
34 //===----------------------------------------------------------------------===//
35 
36 static bool isDispatchBlock(QualType Ty) {
37  // Is it a block pointer?
38  const BlockPointerType *BPT = Ty->getAs<BlockPointerType>();
39  if (!BPT)
40  return false;
41 
42  // Check if the block pointer type takes no arguments and
43  // returns void.
44  const FunctionProtoType *FT =
46  return FT && FT->getReturnType()->isVoidType() && FT->getNumParams() == 0;
47 }
48 
49 namespace {
50 class ASTMaker {
51 public:
52  ASTMaker(ASTContext &C) : C(C) {}
53 
54  /// Create a new BinaryOperator representing a simple assignment.
55  BinaryOperator *makeAssignment(const Expr *LHS, const Expr *RHS, QualType Ty);
56 
57  /// Create a new BinaryOperator representing a comparison.
58  BinaryOperator *makeComparison(const Expr *LHS, const Expr *RHS,
60 
61  /// Create a new compound stmt using the provided statements.
62  CompoundStmt *makeCompound(ArrayRef<Stmt*>);
63 
64  /// Create a new DeclRefExpr for the referenced variable.
65  DeclRefExpr *makeDeclRefExpr(const VarDecl *D,
66  bool RefersToEnclosingVariableOrCapture = false);
67 
68  /// Create a new UnaryOperator representing a dereference.
69  UnaryOperator *makeDereference(const Expr *Arg, QualType Ty);
70 
71  /// Create an implicit cast for an integer conversion.
72  Expr *makeIntegralCast(const Expr *Arg, QualType Ty);
73 
74  /// Create an implicit cast to a builtin boolean type.
75  ImplicitCastExpr *makeIntegralCastToBoolean(const Expr *Arg);
76 
77  /// Create an implicit cast for lvalue-to-rvaluate conversions.
78  ImplicitCastExpr *makeLvalueToRvalue(const Expr *Arg, QualType Ty);
79 
80  /// Make RValue out of variable declaration, creating a temporary
81  /// DeclRefExpr in the process.
83  makeLvalueToRvalue(const VarDecl *Decl,
84  bool RefersToEnclosingVariableOrCapture = false);
85 
86  /// Create an implicit cast of the given type.
87  ImplicitCastExpr *makeImplicitCast(const Expr *Arg, QualType Ty,
88  CastKind CK = CK_LValueToRValue);
89 
90  /// Create an Objective-C bool literal.
91  ObjCBoolLiteralExpr *makeObjCBool(bool Val);
92 
93  /// Create an Objective-C ivar reference.
94  ObjCIvarRefExpr *makeObjCIvarRef(const Expr *Base, const ObjCIvarDecl *IVar);
95 
96  /// Create a Return statement.
97  ReturnStmt *makeReturn(const Expr *RetVal);
98 
99  /// Create an integer literal expression of the given type.
100  IntegerLiteral *makeIntegerLiteral(uint64_t Value, QualType Ty);
101 
102  /// Create a member expression.
103  MemberExpr *makeMemberExpression(Expr *base, ValueDecl *MemberDecl,
104  bool IsArrow = false,
105  ExprValueKind ValueKind = VK_LValue);
106 
107  /// Returns a *first* member field of a record declaration with a given name.
108  /// \return an nullptr if no member with such a name exists.
109  ValueDecl *findMemberField(const RecordDecl *RD, StringRef Name);
110 
111 private:
112  ASTContext &C;
113 };
114 }
115 
116 BinaryOperator *ASTMaker::makeAssignment(const Expr *LHS, const Expr *RHS,
117  QualType Ty) {
118  return new (C) BinaryOperator(const_cast<Expr*>(LHS), const_cast<Expr*>(RHS),
119  BO_Assign, Ty, VK_RValue,
121 }
122 
123 BinaryOperator *ASTMaker::makeComparison(const Expr *LHS, const Expr *RHS,
125  assert(BinaryOperator::isLogicalOp(Op) ||
127  return new (C) BinaryOperator(const_cast<Expr*>(LHS),
128  const_cast<Expr*>(RHS),
129  Op,
130  C.getLogicalOperationType(),
131  VK_RValue,
133 }
134 
135 CompoundStmt *ASTMaker::makeCompound(ArrayRef<Stmt *> Stmts) {
137 }
138 
139 DeclRefExpr *ASTMaker::makeDeclRefExpr(
140  const VarDecl *D,
141  bool RefersToEnclosingVariableOrCapture) {
143 
145  C, NestedNameSpecifierLoc(), SourceLocation(), const_cast<VarDecl *>(D),
146  RefersToEnclosingVariableOrCapture, SourceLocation(), Type, VK_LValue);
147  return DR;
148 }
149 
150 UnaryOperator *ASTMaker::makeDereference(const Expr *Arg, QualType Ty) {
151  return new (C) UnaryOperator(const_cast<Expr*>(Arg), UO_Deref, Ty,
153  /*CanOverflow*/ false);
154 }
155 
156 ImplicitCastExpr *ASTMaker::makeLvalueToRvalue(const Expr *Arg, QualType Ty) {
157  return makeImplicitCast(Arg, Ty, CK_LValueToRValue);
158 }
159 
161 ASTMaker::makeLvalueToRvalue(const VarDecl *Arg,
162  bool RefersToEnclosingVariableOrCapture) {
164  return makeLvalueToRvalue(makeDeclRefExpr(Arg,
165  RefersToEnclosingVariableOrCapture),
166  Type);
167 }
168 
169 ImplicitCastExpr *ASTMaker::makeImplicitCast(const Expr *Arg, QualType Ty,
170  CastKind CK) {
171  return ImplicitCastExpr::Create(C, Ty,
172  /* CastKind=*/ CK,
173  /* Expr=*/ const_cast<Expr *>(Arg),
174  /* CXXCastPath=*/ nullptr,
175  /* ExprValueKind=*/ VK_RValue);
176 }
177 
178 Expr *ASTMaker::makeIntegralCast(const Expr *Arg, QualType Ty) {
179  if (Arg->getType() == Ty)
180  return const_cast<Expr*>(Arg);
181 
182  return ImplicitCastExpr::Create(C, Ty, CK_IntegralCast,
183  const_cast<Expr*>(Arg), nullptr, VK_RValue);
184 }
185 
186 ImplicitCastExpr *ASTMaker::makeIntegralCastToBoolean(const Expr *Arg) {
187  return ImplicitCastExpr::Create(C, C.BoolTy, CK_IntegralToBoolean,
188  const_cast<Expr*>(Arg), nullptr, VK_RValue);
189 }
190 
191 ObjCBoolLiteralExpr *ASTMaker::makeObjCBool(bool Val) {
192  QualType Ty = C.getBOOLDecl() ? C.getBOOLType() : C.ObjCBuiltinBoolTy;
193  return new (C) ObjCBoolLiteralExpr(Val, Ty, SourceLocation());
194 }
195 
196 ObjCIvarRefExpr *ASTMaker::makeObjCIvarRef(const Expr *Base,
197  const ObjCIvarDecl *IVar) {
198  return new (C) ObjCIvarRefExpr(const_cast<ObjCIvarDecl*>(IVar),
199  IVar->getType(), SourceLocation(),
200  SourceLocation(), const_cast<Expr*>(Base),
201  /*arrow=*/true, /*free=*/false);
202 }
203 
204 
205 ReturnStmt *ASTMaker::makeReturn(const Expr *RetVal) {
206  return new (C) ReturnStmt(SourceLocation(), const_cast<Expr*>(RetVal),
207  nullptr);
208 }
209 
210 IntegerLiteral *ASTMaker::makeIntegerLiteral(uint64_t Value, QualType Ty) {
211  llvm::APInt APValue = llvm::APInt(C.getTypeSize(Ty), Value);
212  return IntegerLiteral::Create(C, APValue, Ty, SourceLocation());
213 }
214 
215 MemberExpr *ASTMaker::makeMemberExpression(Expr *base, ValueDecl *MemberDecl,
216  bool IsArrow,
217  ExprValueKind ValueKind) {
218 
219  DeclAccessPair FoundDecl = DeclAccessPair::make(MemberDecl, AS_public);
220  return MemberExpr::Create(
221  C, base, IsArrow, SourceLocation(), NestedNameSpecifierLoc(),
222  SourceLocation(), MemberDecl, FoundDecl,
224  /* TemplateArgumentListInfo=*/ nullptr, MemberDecl->getType(), ValueKind,
225  OK_Ordinary);
226 }
227 
228 ValueDecl *ASTMaker::findMemberField(const RecordDecl *RD, StringRef Name) {
229 
230  CXXBasePaths Paths(
231  /* FindAmbiguities=*/false,
232  /* RecordPaths=*/false,
233  /* DetectVirtual=*/ false);
234  const IdentifierInfo &II = C.Idents.get(Name);
235  DeclarationName DeclName = C.DeclarationNames.getIdentifier(&II);
236 
237  DeclContextLookupResult Decls = RD->lookup(DeclName);
238  for (NamedDecl *FoundDecl : Decls)
239  if (!FoundDecl->getDeclContext()->isFunctionOrMethod())
240  return cast<ValueDecl>(FoundDecl);
241 
242  return nullptr;
243 }
244 
245 //===----------------------------------------------------------------------===//
246 // Creation functions for faux ASTs.
247 //===----------------------------------------------------------------------===//
248 
249 typedef Stmt *(*FunctionFarmer)(ASTContext &C, const FunctionDecl *D);
250 
252  const ParmVarDecl *Callback,
253  ArrayRef<Expr *> CallArgs) {
254 
255  QualType Ty = Callback->getType();
256  DeclRefExpr *Call = M.makeDeclRefExpr(Callback);
257  Expr *SubExpr;
258  if (Ty->isRValueReferenceType()) {
259  SubExpr = M.makeImplicitCast(
260  Call, Ty.getNonReferenceType(), CK_LValueToRValue);
261  } else if (Ty->isLValueReferenceType() &&
262  Call->getType()->isFunctionType()) {
263  Ty = C.getPointerType(Ty.getNonReferenceType());
264  SubExpr = M.makeImplicitCast(Call, Ty, CK_FunctionToPointerDecay);
265  } else if (Ty->isLValueReferenceType()
266  && Call->getType()->isPointerType()
267  && Call->getType()->getPointeeType()->isFunctionType()){
268  SubExpr = Call;
269  } else {
270  llvm_unreachable("Unexpected state");
271  }
272 
273  return new (C)
274  CallExpr(C, SubExpr, CallArgs, C.VoidTy, VK_RValue, SourceLocation());
275 }
276 
278  const ParmVarDecl *Callback,
279  CXXRecordDecl *CallbackDecl,
280  ArrayRef<Expr *> CallArgs) {
281  assert(CallbackDecl != nullptr);
282  assert(CallbackDecl->isLambda());
283  FunctionDecl *callOperatorDecl = CallbackDecl->getLambdaCallOperator();
284  assert(callOperatorDecl != nullptr);
285 
286  DeclRefExpr *callOperatorDeclRef =
287  DeclRefExpr::Create(/* Ctx =*/ C,
288  /* QualifierLoc =*/ NestedNameSpecifierLoc(),
289  /* TemplateKWLoc =*/ SourceLocation(),
290  const_cast<FunctionDecl *>(callOperatorDecl),
291  /* RefersToEnclosingVariableOrCapture=*/ false,
292  /* NameLoc =*/ SourceLocation(),
293  /* T =*/ callOperatorDecl->getType(),
294  /* VK =*/ VK_LValue);
295 
296  return new (C)
297  CXXOperatorCallExpr(/*AstContext=*/C, OO_Call, callOperatorDeclRef,
298  /*args=*/CallArgs,
299  /*QualType=*/C.VoidTy,
300  /*ExprValueType=*/VK_RValue,
301  /*SourceLocation=*/SourceLocation(), FPOptions());
302 }
303 
304 /// Create a fake body for std::call_once.
305 /// Emulates the following function body:
306 ///
307 /// \code
308 /// typedef struct once_flag_s {
309 /// unsigned long __state = 0;
310 /// } once_flag;
311 /// template<class Callable>
312 /// void call_once(once_flag& o, Callable func) {
313 /// if (!o.__state) {
314 /// func();
315 /// }
316 /// o.__state = 1;
317 /// }
318 /// \endcode
320  LLVM_DEBUG(llvm::dbgs() << "Generating body for call_once\n");
321 
322  // We need at least two parameters.
323  if (D->param_size() < 2)
324  return nullptr;
325 
326  ASTMaker M(C);
327 
328  const ParmVarDecl *Flag = D->getParamDecl(0);
329  const ParmVarDecl *Callback = D->getParamDecl(1);
330 
331  if (!Callback->getType()->isReferenceType()) {
332  llvm::dbgs() << "libcxx03 std::call_once implementation, skipping.\n";
333  return nullptr;
334  }
335  if (!Flag->getType()->isReferenceType()) {
336  llvm::dbgs() << "unknown std::call_once implementation, skipping.\n";
337  return nullptr;
338  }
339 
340  QualType CallbackType = Callback->getType().getNonReferenceType();
341 
342  // Nullable pointer, non-null iff function is a CXXRecordDecl.
343  CXXRecordDecl *CallbackRecordDecl = CallbackType->getAsCXXRecordDecl();
344  QualType FlagType = Flag->getType().getNonReferenceType();
345  auto *FlagRecordDecl = FlagType->getAsRecordDecl();
346 
347  if (!FlagRecordDecl) {
348  LLVM_DEBUG(llvm::dbgs() << "Flag field is not a record: "
349  << "unknown std::call_once implementation, "
350  << "ignoring the call.\n");
351  return nullptr;
352  }
353 
354  // We initially assume libc++ implementation of call_once,
355  // where the once_flag struct has a field `__state_`.
356  ValueDecl *FlagFieldDecl = M.findMemberField(FlagRecordDecl, "__state_");
357 
358  // Otherwise, try libstdc++ implementation, with a field
359  // `_M_once`
360  if (!FlagFieldDecl) {
361  FlagFieldDecl = M.findMemberField(FlagRecordDecl, "_M_once");
362  }
363 
364  if (!FlagFieldDecl) {
365  LLVM_DEBUG(llvm::dbgs() << "No field _M_once or __state_ found on "
366  << "std::once_flag struct: unknown std::call_once "
367  << "implementation, ignoring the call.");
368  return nullptr;
369  }
370 
371  bool isLambdaCall = CallbackRecordDecl && CallbackRecordDecl->isLambda();
372  if (CallbackRecordDecl && !isLambdaCall) {
373  LLVM_DEBUG(llvm::dbgs()
374  << "Not supported: synthesizing body for functors when "
375  << "body farming std::call_once, ignoring the call.");
376  return nullptr;
377  }
378 
379  SmallVector<Expr *, 5> CallArgs;
380  const FunctionProtoType *CallbackFunctionType;
381  if (isLambdaCall) {
382 
383  // Lambda requires callback itself inserted as a first parameter.
384  CallArgs.push_back(
385  M.makeDeclRefExpr(Callback,
386  /* RefersToEnclosingVariableOrCapture=*/ true));
387  CallbackFunctionType = CallbackRecordDecl->getLambdaCallOperator()
388  ->getType()
390  } else if (!CallbackType->getPointeeType().isNull()) {
391  CallbackFunctionType =
392  CallbackType->getPointeeType()->getAs<FunctionProtoType>();
393  } else {
394  CallbackFunctionType = CallbackType->getAs<FunctionProtoType>();
395  }
396 
397  if (!CallbackFunctionType)
398  return nullptr;
399 
400  // First two arguments are used for the flag and for the callback.
401  if (D->getNumParams() != CallbackFunctionType->getNumParams() + 2) {
402  LLVM_DEBUG(llvm::dbgs() << "Types of params of the callback do not match "
403  << "params passed to std::call_once, "
404  << "ignoring the call\n");
405  return nullptr;
406  }
407 
408  // All arguments past first two ones are passed to the callback,
409  // and we turn lvalues into rvalues if the argument is not passed by
410  // reference.
411  for (unsigned int ParamIdx = 2; ParamIdx < D->getNumParams(); ParamIdx++) {
412  const ParmVarDecl *PDecl = D->getParamDecl(ParamIdx);
413  if (PDecl &&
414  CallbackFunctionType->getParamType(ParamIdx - 2)
416  .getCanonicalType() !=
418  LLVM_DEBUG(llvm::dbgs() << "Types of params of the callback do not match "
419  << "params passed to std::call_once, "
420  << "ignoring the call\n");
421  return nullptr;
422  }
423  Expr *ParamExpr = M.makeDeclRefExpr(PDecl);
424  if (!CallbackFunctionType->getParamType(ParamIdx - 2)->isReferenceType()) {
425  QualType PTy = PDecl->getType().getNonReferenceType();
426  ParamExpr = M.makeLvalueToRvalue(ParamExpr, PTy);
427  }
428  CallArgs.push_back(ParamExpr);
429  }
430 
431  CallExpr *CallbackCall;
432  if (isLambdaCall) {
433 
434  CallbackCall = create_call_once_lambda_call(C, M, Callback,
435  CallbackRecordDecl, CallArgs);
436  } else {
437 
438  // Function pointer case.
439  CallbackCall = create_call_once_funcptr_call(C, M, Callback, CallArgs);
440  }
441 
442  DeclRefExpr *FlagDecl =
443  M.makeDeclRefExpr(Flag,
444  /* RefersToEnclosingVariableOrCapture=*/true);
445 
446 
447  MemberExpr *Deref = M.makeMemberExpression(FlagDecl, FlagFieldDecl);
448  assert(Deref->isLValue());
449  QualType DerefType = Deref->getType();
450 
451  // Negation predicate.
452  UnaryOperator *FlagCheck = new (C) UnaryOperator(
453  /* input=*/
454  M.makeImplicitCast(M.makeLvalueToRvalue(Deref, DerefType), DerefType,
455  CK_IntegralToBoolean),
456  /* opc=*/ UO_LNot,
457  /* QualType=*/ C.IntTy,
458  /* ExprValueKind=*/ VK_RValue,
459  /* ExprObjectKind=*/ OK_Ordinary, SourceLocation(),
460  /* CanOverflow*/ false);
461 
462  // Create assignment.
463  BinaryOperator *FlagAssignment = M.makeAssignment(
464  Deref, M.makeIntegralCast(M.makeIntegerLiteral(1, C.IntTy), DerefType),
465  DerefType);
466 
467  IfStmt *Out = new (C)
468  IfStmt(C, SourceLocation(),
469  /* IsConstexpr=*/ false,
470  /* init=*/ nullptr,
471  /* var=*/ nullptr,
472  /* cond=*/ FlagCheck,
473  /* then=*/ M.makeCompound({CallbackCall, FlagAssignment}));
474 
475  return Out;
476 }
477 
478 /// Create a fake body for dispatch_once.
480  // Check if we have at least two parameters.
481  if (D->param_size() != 2)
482  return nullptr;
483 
484  // Check if the first parameter is a pointer to integer type.
485  const ParmVarDecl *Predicate = D->getParamDecl(0);
486  QualType PredicateQPtrTy = Predicate->getType();
487  const PointerType *PredicatePtrTy = PredicateQPtrTy->getAs<PointerType>();
488  if (!PredicatePtrTy)
489  return nullptr;
490  QualType PredicateTy = PredicatePtrTy->getPointeeType();
491  if (!PredicateTy->isIntegerType())
492  return nullptr;
493 
494  // Check if the second parameter is the proper block type.
495  const ParmVarDecl *Block = D->getParamDecl(1);
496  QualType Ty = Block->getType();
497  if (!isDispatchBlock(Ty))
498  return nullptr;
499 
500  // Everything checks out. Create a fakse body that checks the predicate,
501  // sets it, and calls the block. Basically, an AST dump of:
502  //
503  // void dispatch_once(dispatch_once_t *predicate, dispatch_block_t block) {
504  // if (*predicate != ~0l) {
505  // *predicate = ~0l;
506  // block();
507  // }
508  // }
509 
510  ASTMaker M(C);
511 
512  // (1) Create the call.
513  CallExpr *CE = new (C) CallExpr(
514  /*ASTContext=*/C,
515  /*StmtClass=*/M.makeLvalueToRvalue(/*Expr=*/Block),
516  /*args=*/None,
517  /*QualType=*/C.VoidTy,
518  /*ExprValueType=*/VK_RValue,
519  /*SourceLocation=*/SourceLocation());
520 
521  // (2) Create the assignment to the predicate.
522  Expr *DoneValue =
523  new (C) UnaryOperator(M.makeIntegerLiteral(0, C.LongTy), UO_Not, C.LongTy,
525  /*CanOverflow*/false);
526 
527  BinaryOperator *B =
528  M.makeAssignment(
529  M.makeDereference(
530  M.makeLvalueToRvalue(
531  M.makeDeclRefExpr(Predicate), PredicateQPtrTy),
532  PredicateTy),
533  M.makeIntegralCast(DoneValue, PredicateTy),
534  PredicateTy);
535 
536  // (3) Create the compound statement.
537  Stmt *Stmts[] = { B, CE };
538  CompoundStmt *CS = M.makeCompound(Stmts);
539 
540  // (4) Create the 'if' condition.
541  ImplicitCastExpr *LValToRval =
542  M.makeLvalueToRvalue(
543  M.makeDereference(
544  M.makeLvalueToRvalue(
545  M.makeDeclRefExpr(Predicate),
546  PredicateQPtrTy),
547  PredicateTy),
548  PredicateTy);
549 
550  Expr *GuardCondition = M.makeComparison(LValToRval, DoneValue, BO_NE);
551  // (5) Create the 'if' statement.
552  IfStmt *If = new (C) IfStmt(C, SourceLocation(),
553  /* IsConstexpr=*/ false,
554  /* init=*/ nullptr,
555  /* var=*/ nullptr,
556  /* cond=*/ GuardCondition,
557  /* then=*/ CS);
558  return If;
559 }
560 
561 /// Create a fake body for dispatch_sync.
563  // Check if we have at least two parameters.
564  if (D->param_size() != 2)
565  return nullptr;
566 
567  // Check if the second parameter is a block.
568  const ParmVarDecl *PV = D->getParamDecl(1);
569  QualType Ty = PV->getType();
570  if (!isDispatchBlock(Ty))
571  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  ASTMaker M(C);
581  DeclRefExpr *DR = M.makeDeclRefExpr(PV);
582  ImplicitCastExpr *ICE = M.makeLvalueToRvalue(DR, Ty);
583  CallExpr *CE = new (C) CallExpr(C, ICE, None, C.VoidTy, VK_RValue,
584  SourceLocation());
585  return CE;
586 }
587 
589 {
590  // There are exactly 3 arguments.
591  if (D->param_size() != 3)
592  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  QualType ResultTy = D->getReturnType();
606  bool isBoolean = ResultTy->isBooleanType();
607  if (!isBoolean && !ResultTy->isIntegralType(C))
608  return nullptr;
609 
610  const ParmVarDecl *OldValue = D->getParamDecl(0);
611  QualType OldValueTy = OldValue->getType();
612 
613  const ParmVarDecl *NewValue = D->getParamDecl(1);
614  QualType NewValueTy = NewValue->getType();
615 
616  assert(OldValueTy == NewValueTy);
617 
618  const ParmVarDecl *TheValue = D->getParamDecl(2);
619  QualType TheValueTy = TheValue->getType();
620  const PointerType *PT = TheValueTy->getAs<PointerType>();
621  if (!PT)
622  return nullptr;
623  QualType PointeeTy = PT->getPointeeType();
624 
625  ASTMaker M(C);
626  // Construct the comparison.
627  Expr *Comparison =
628  M.makeComparison(
629  M.makeLvalueToRvalue(M.makeDeclRefExpr(OldValue), OldValueTy),
630  M.makeLvalueToRvalue(
631  M.makeDereference(
632  M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy),
633  PointeeTy),
634  PointeeTy),
635  BO_EQ);
636 
637  // Construct the body of the IfStmt.
638  Stmt *Stmts[2];
639  Stmts[0] =
640  M.makeAssignment(
641  M.makeDereference(
642  M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy),
643  PointeeTy),
644  M.makeLvalueToRvalue(M.makeDeclRefExpr(NewValue), NewValueTy),
645  NewValueTy);
646 
647  Expr *BoolVal = M.makeObjCBool(true);
648  Expr *RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal)
649  : M.makeIntegralCast(BoolVal, ResultTy);
650  Stmts[1] = M.makeReturn(RetVal);
651  CompoundStmt *Body = M.makeCompound(Stmts);
652 
653  // Construct the else clause.
654  BoolVal = M.makeObjCBool(false);
655  RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal)
656  : M.makeIntegralCast(BoolVal, ResultTy);
657  Stmt *Else = M.makeReturn(RetVal);
658 
659  /// Construct the If.
660  Stmt *If = new (C) IfStmt(C, SourceLocation(), false, nullptr, nullptr,
661  Comparison, Body, SourceLocation(), Else);
662 
663  return If;
664 }
665 
667  D = D->getCanonicalDecl();
668 
669  Optional<Stmt *> &Val = Bodies[D];
670  if (Val.hasValue())
671  return Val.getValue();
672 
673  Val = nullptr;
674 
675  if (D->getIdentifier() == nullptr)
676  return nullptr;
677 
678  StringRef Name = D->getName();
679  if (Name.empty())
680  return nullptr;
681 
682  FunctionFarmer FF;
683 
684  if (Name.startswith("OSAtomicCompareAndSwap") ||
685  Name.startswith("objc_atomicCompareAndSwap")) {
687  } else if (Name == "call_once" && D->getDeclContext()->isStdNamespace()) {
688  FF = create_call_once;
689  } else {
690  FF = llvm::StringSwitch<FunctionFarmer>(Name)
691  .Case("dispatch_sync", create_dispatch_sync)
692  .Case("dispatch_once", create_dispatch_once)
693  .Default(nullptr);
694  }
695 
696  if (FF) { Val = FF(C, D); }
697  else if (Injector) { Val = Injector->getBody(D); }
698  return Val.getValue();
699 }
700 
701 static const ObjCIvarDecl *findBackingIvar(const ObjCPropertyDecl *Prop) {
702  const ObjCIvarDecl *IVar = Prop->getPropertyIvarDecl();
703 
704  if (IVar)
705  return IVar;
706 
707  // When a readonly property is shadowed in a class extensions with a
708  // a readwrite property, the instance variable belongs to the shadowing
709  // property rather than the shadowed property. If there is no instance
710  // variable on a readonly property, check to see whether the property is
711  // shadowed and if so try to get the instance variable from shadowing
712  // property.
713  if (!Prop->isReadOnly())
714  return nullptr;
715 
716  auto *Container = cast<ObjCContainerDecl>(Prop->getDeclContext());
717  const ObjCInterfaceDecl *PrimaryInterface = nullptr;
718  if (auto *InterfaceDecl = dyn_cast<ObjCInterfaceDecl>(Container)) {
719  PrimaryInterface = InterfaceDecl;
720  } else if (auto *CategoryDecl = dyn_cast<ObjCCategoryDecl>(Container)) {
721  PrimaryInterface = CategoryDecl->getClassInterface();
722  } else if (auto *ImplDecl = dyn_cast<ObjCImplDecl>(Container)) {
723  PrimaryInterface = ImplDecl->getClassInterface();
724  } else {
725  return nullptr;
726  }
727 
728  // FindPropertyVisibleInPrimaryClass() looks first in class extensions, so it
729  // is guaranteed to find the shadowing property, if it exists, rather than
730  // the shadowed property.
731  auto *ShadowingProp = PrimaryInterface->FindPropertyVisibleInPrimaryClass(
732  Prop->getIdentifier(), Prop->getQueryKind());
733  if (ShadowingProp && ShadowingProp != Prop) {
734  IVar = ShadowingProp->getPropertyIvarDecl();
735  }
736 
737  return IVar;
738 }
739 
741  const ObjCPropertyDecl *Prop) {
742  // First, find the backing ivar.
743  const ObjCIvarDecl *IVar = findBackingIvar(Prop);
744  if (!IVar)
745  return nullptr;
746 
747  // Ignore weak variables, which have special behavior.
749  return nullptr;
750 
751  // Look to see if Sema has synthesized a body for us. This happens in
752  // Objective-C++ because the return value may be a C++ class type with a
753  // non-trivial copy constructor. We can only do this if we can find the
754  // @synthesize for this property, though (or if we know it's been auto-
755  // synthesized).
756  const ObjCImplementationDecl *ImplDecl =
758  if (ImplDecl) {
759  for (const auto *I : ImplDecl->property_impls()) {
760  if (I->getPropertyDecl() != Prop)
761  continue;
762 
763  if (I->getGetterCXXConstructor()) {
764  ASTMaker M(Ctx);
765  return M.makeReturn(I->getGetterCXXConstructor());
766  }
767  }
768  }
769 
770  // Sanity check that the property is the same type as the ivar, or a
771  // reference to it, and that it is either an object pointer or trivially
772  // copyable.
773  if (!Ctx.hasSameUnqualifiedType(IVar->getType(),
774  Prop->getType().getNonReferenceType()))
775  return nullptr;
776  if (!IVar->getType()->isObjCLifetimeType() &&
777  !IVar->getType().isTriviallyCopyableType(Ctx))
778  return nullptr;
779 
780  // Generate our body:
781  // return self->_ivar;
782  ASTMaker M(Ctx);
783 
784  const VarDecl *selfVar = Prop->getGetterMethodDecl()->getSelfDecl();
785  if (!selfVar)
786  return nullptr;
787 
788  Expr *loadedIVar =
789  M.makeObjCIvarRef(
790  M.makeLvalueToRvalue(
791  M.makeDeclRefExpr(selfVar),
792  selfVar->getType()),
793  IVar);
794 
795  if (!Prop->getType()->isReferenceType())
796  loadedIVar = M.makeLvalueToRvalue(loadedIVar, IVar->getType());
797 
798  return M.makeReturn(loadedIVar);
799 }
800 
802  // We currently only know how to synthesize property accessors.
803  if (!D->isPropertyAccessor())
804  return nullptr;
805 
806  D = D->getCanonicalDecl();
807 
808  Optional<Stmt *> &Val = Bodies[D];
809  if (Val.hasValue())
810  return Val.getValue();
811  Val = nullptr;
812 
813  const ObjCPropertyDecl *Prop = D->findPropertyDecl();
814  if (!Prop)
815  return nullptr;
816 
817  // For now, we only synthesize getters.
818  // Synthesizing setters would cause false negatives in the
819  // RetainCountChecker because the method body would bind the parameter
820  // to an instance variable, causing it to escape. This would prevent
821  // warning in the following common scenario:
822  //
823  // id foo = [[NSObject alloc] init];
824  // self.foo = foo; // We should warn that foo leaks here.
825  //
826  if (D->param_size() != 0)
827  return nullptr;
828 
829  Val = createObjCPropertyGetter(C, Prop);
830 
831  return Val.getValue();
832 }
A call to an overloaded operator written using operator syntax.
Definition: ExprCXX.h:78
Defines the clang::ASTContext interface.
ObjCPropertyQueryKind getQueryKind() const
Definition: DeclObjC.h:873
Represents a function declaration or definition.
Definition: Decl.h:1732
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2533
QualType getPointeeType() const
Definition: Type.h:2546
A (possibly-)qualified type.
Definition: Type.h:642
unsigned param_size() const
Definition: DeclObjC.h:341
Stmt - This represents one statement.
Definition: Stmt.h:66
IfStmt - This represents an if/then/else.
Definition: Stmt.h:959
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:497
bool isLogicalOp() const
Definition: Expr.h:3228
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:87
static Stmt * create_call_once(ASTContext &C, const FunctionDecl *D)
Create a fake body for std::call_once.
Definition: BodyFarm.cpp:319
static CallExpr * create_call_once_funcptr_call(ASTContext &C, ASTMaker M, const ParmVarDecl *Callback, ArrayRef< Expr *> CallArgs)
Definition: BodyFarm.cpp:251
QualType getNonReferenceType() const
If Type is a reference type (e.g., const int&), returns the type that the reference refers to ("const...
Definition: Type.h:6219
The base class of the type hierarchy.
Definition: Type.h:1415
CanQualType LongTy
Definition: ASTContext.h:1034
Floating point control options.
Definition: LangOptions.h:274
size_t param_size() const
Definition: Decl.h:2262
static bool isDispatchBlock(QualType Ty)
Definition: BodyFarm.cpp:36
Represents a variable declaration or definition.
Definition: Decl.h:812
QualType getReturnType() const
Definition: Decl.h:2286
unsigned getNumParams() const
Definition: Type.h:3869
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6683
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:139
Represents a parameter to a function.
Definition: Decl.h:1551
Defines the clang::Expr interface and subclasses for C++ expressions.
IdentifierInfo * getIdentifier() const
Get the identifier that names this declaration, if there is one.
Definition: Decl.h:269
Represents a struct/union/class.
Definition: Decl.h:3585
DeclarationName getDeclName() const
Get the actual, stored name of the declaration, which may be a special name.
Definition: Decl.h:297
One of these records is kept for each identifier that is lexed.
QualType getPointeeType() const
Definition: Type.h:2650
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:154
A C++ nested-name-specifier augmented with source location information.
The results of name lookup within a DeclContext.
Definition: DeclBase.h:1186
bool isObjCLifetimeType() const
Returns true if objects of this type have lifetime semantics under ARC.
Definition: Type.cpp:3909
Defines the clang::CodeInjector interface which is responsible for injecting AST of function definiti...
bool isReferenceType() const
Definition: Type.h:6282
static DeclRefExpr * Create(const ASTContext &Context, NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKWLoc, ValueDecl *D, bool RefersToEnclosingVariableOrCapture, SourceLocation NameLoc, QualType T, ExprValueKind VK, NamedDecl *FoundD=nullptr, const TemplateArgumentListInfo *TemplateArgs=nullptr)
Definition: Expr.cpp:391
An r-value expression (a pr-value in the C++11 taxonomy) produces a temporary value.
Definition: Specifiers.h:110
BinaryOperatorKind
static DeclAccessPair make(NamedDecl *D, AccessSpecifier AS)
bool isTriviallyCopyableType(const ASTContext &Context) const
Return true if this is a trivially copyable type (C++0x [basic.types]p9)
Definition: Type.cpp:2197
PropertyAttributeKind getPropertyAttributes() const
Definition: DeclObjC.h:832
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3107
static CompoundStmt * Create(const ASTContext &C, ArrayRef< Stmt *> Stmts, SourceLocation LB, SourceLocation RB)
Definition: Stmt.cpp:326
bool isRValueReferenceType() const
Definition: Type.h:6290
bool isReadOnly() const
isReadOnly - Return true iff the property has a setter.
Definition: DeclObjC.h:855
bool isLambda() const
Determine whether this class describes a lambda function object.
Definition: DeclCXX.h:1196
static IntegerLiteral * Create(const ASTContext &C, const llvm::APInt &V, QualType type, SourceLocation l)
Returns a new integer literal with value &#39;V&#39; and type &#39;type&#39;.
Definition: Expr.cpp:752
An ordinary object is located at an address in memory.
Definition: Specifiers.h:126
Represents an ObjC class declaration.
Definition: DeclObjC.h:1164
Stmt *(* FunctionFarmer)(ASTContext &C, const FunctionDecl *D)
Definition: BodyFarm.cpp:249
ObjCMethodDecl * getCanonicalDecl() override
Retrieves the "canonical" declaration of the given declaration.
Definition: DeclObjC.cpp:954
lookup_result lookup(DeclarationName Name) const
lookup - Find the declarations (if any) with the given Name in this context.
Definition: DeclBase.cpp:1590
RecordDecl * getAsRecordDecl() const
Retrieves the RecordDecl this type refers to.
Definition: Type.cpp:1609
CompoundStmt - This represents a group of statements like { stmt stmt }.
Definition: Stmt.h:613
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1605
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3676
CastKind
CastKind - The kind of operation required for a conversion.
static ImplicitCastExpr * Create(const ASTContext &Context, QualType T, CastKind Kind, Expr *Operand, const CXXCastPath *BasePath, ExprValueKind Cat)
Definition: Expr.cpp:1786
static const ObjCIvarDecl * findBackingIvar(const ObjCPropertyDecl *Prop)
Definition: BodyFarm.cpp:701
A single parameter index whose accessors require each use to make explicit the parameter index encodi...
Definition: Attr.h:213
Represent the declaration of a variable (in which case it is an lvalue) a function (in which case it ...
Definition: Decl.h:636
This represents one expression.
Definition: Expr.h:105
ExprValueKind
The categorization of expression values, currently following the C++11 scheme.
Definition: Specifiers.h:107
Defines an enumeration for C++ overloaded operators.
DeclContext * getDeclContext()
Definition: DeclBase.h:427
ObjCPropertyDecl * FindPropertyVisibleInPrimaryClass(IdentifierInfo *PropertyId, ObjCPropertyQueryKind QueryKind) const
FindPropertyVisibleInPrimaryClass - Finds declaration of the property with name &#39;PropertyId&#39; in the p...
Definition: DeclObjC.cpp:369
QualType getType() const
Definition: Expr.h:127
bool isFunctionOrMethod() const
Definition: DeclBase.h:1799
propimpl_range property_impls() const
Definition: DeclObjC.h:2459
ReturnStmt - This represents a return, optionally of an expression: return; return 4;...
Definition: Stmt.h:1444
static Stmt * create_OSAtomicCompareAndSwap(ASTContext &C, const FunctionDecl *D)
Definition: BodyFarm.cpp:588
UnaryOperator - This represents the unary-expression&#39;s (except sizeof and alignof), the postinc/postdec operators from postfix-expression, and various extensions.
Definition: Expr.h:1789
static Stmt * createObjCPropertyGetter(ASTContext &Ctx, const ObjCPropertyDecl *Prop)
Definition: BodyFarm.cpp:740
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:707
ImplicitParamDecl * getSelfDecl() const
Definition: DeclObjC.h:406
QualType getType() const
Definition: DeclObjC.h:821
bool isComparisonOp() const
Definition: Expr.h:3198
QualType getCanonicalType() const
Definition: Type.h:6085
Encodes a location in the source.
QualType getReturnType() const
Definition: Type.h:3607
static Stmt * create_dispatch_sync(ASTContext &C, const FunctionDecl *D)
Create a fake body for dispatch_sync.
Definition: BodyFarm.cpp:562
static CallExpr * create_call_once_lambda_call(ASTContext &C, ASTMaker M, const ParmVarDecl *Callback, CXXRecordDecl *CallbackDecl, ArrayRef< Expr *> CallArgs)
Definition: BodyFarm.cpp:277
bool isIntegralType(const ASTContext &Ctx) const
Determine whether this type is an integral type.
Definition: Type.cpp:1751
bool isStdNamespace() const
Definition: DeclBase.cpp:1065
const ParmVarDecl * getParamDecl(unsigned i) const
Definition: Decl.h:2269
CanQualType VoidTy
Definition: ASTContext.h:1025
Represents one property declaration in an Objective-C interface.
Definition: DeclObjC.h:721
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:2929
bool isLValue() const
isLValue - True if this expression is an "l-value" according to the rules of the current language...
Definition: Expr.h:248
ObjCImplementationDecl * getImplementation() const
Definition: DeclObjC.cpp:1549
bool hasSameUnqualifiedType(QualType T1, QualType T2) const
Determine whether the given types are equivalent after cvr-qualifiers have been removed.
Definition: ASTContext.h:2299
static MemberExpr * Create(const ASTContext &C, Expr *base, bool isarrow, SourceLocation OperatorLoc, NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKWLoc, ValueDecl *memberdecl, DeclAccessPair founddecl, DeclarationNameInfo MemberNameInfo, const TemplateArgumentListInfo *targs, QualType ty, ExprValueKind VK, ExprObjectKind OK)
Definition: Expr.cpp:1472
A POD class for pairing a NamedDecl* with an access specifier.
static Stmt * create_dispatch_once(ASTContext &C, const FunctionDecl *D)
Create a fake body for dispatch_once.
Definition: BodyFarm.cpp:479
Dataflow Directional Tag Classes.
CXXMethodDecl * getLambdaCallOperator() const
Retrieve the lambda call operator of the closure type if this is a closure type.
Definition: DeclCXX.cpp:1362
The name of a declaration.
bool isBooleanType() const
Definition: Type.h:6610
Stmt * getBody(const FunctionDecl *D)
Factory method for creating bodies for ordinary functions.
Definition: BodyFarm.cpp:666
const ObjCInterfaceDecl * getContainingInterface() const
Return the class interface that this ivar is logically contained in; this is either the interface whe...
Definition: DeclObjC.cpp:1790
DeclarationNameInfo - A collector data type for bundling together a DeclarationName and the correspnd...
Pointer to a block type.
Definition: Type.h:2635
ObjCImplementationDecl - Represents a class definition - this is where method definitions are specifi...
Definition: DeclObjC.h:2544
bool isIntegerType() const
isIntegerType() does not include complex integers (a GCC extension).
Definition: Type.h:6531
bool isFunctionType() const
Definition: Type.h:6266
APValue - This class implements a discriminated union of [uninitialized] [APSInt] [APFloat]...
Definition: APValue.h:38
ObjCIvarRefExpr - A reference to an ObjC instance variable.
Definition: ExprObjC.h:513
bool isLValueReferenceType() const
Definition: Type.h:6286
const ObjCPropertyDecl * findPropertyDecl(bool CheckOverrides=true) const
Returns the property associated with this method&#39;s selector.
Definition: DeclObjC.cpp:1302
QualType getParamType(unsigned i) const
Definition: Type.h:3871
MemberExpr - [C99 6.5.2.3] Structure and Union Members.
Definition: Expr.h:2472
Represents a C++ struct/union/class.
Definition: DeclCXX.h:300
bool isVoidType() const
Definition: Type.h:6497
ObjCIvarDecl - Represents an ObjC instance variable.
Definition: DeclObjC.h:1937
ObjCIvarDecl * getPropertyIvarDecl() const
Definition: DeclObjC.h:937
QualType getPointerType(QualType T) const
Return the uniqued reference to the type for a pointer to the specified type.
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2290
StringRef getName() const
Get the name of identifier for this declaration as a StringRef.
Definition: Decl.h:275
CanQualType IntTy
Definition: ASTContext.h:1034
ObjCBoolLiteralExpr - Objective-C Boolean Literal.
Definition: ExprObjC.h:82
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:976
bool isPointerType() const
Definition: Type.h:6270
BasePaths - Represents the set of paths from a derived class to one of its (direct or indirect) bases...
QualType getType() const
Definition: Decl.h:647
An l-value expression is a reference to an object with independent storage.
Definition: Specifiers.h:114
FunctionDecl * getCanonicalDecl() override
Retrieves the "canonical" declaration of the given declaration.
Definition: Decl.cpp:2965
ObjCMethodDecl * getGetterMethodDecl() const
Definition: DeclObjC.h:914
This represents a decl that may have a name.
Definition: Decl.h:248
bool isPropertyAccessor() const
Definition: DeclObjC.h:424
unsigned getNumParams() const
Return the number of parameters this function must have based on its FunctionType.
Definition: Decl.cpp:3037
Comparison