1 //== BodyFarm.cpp - Factory for conjuring up fake bodies ----------*- C++ -*-//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // BodyFarm is a factory for creating faux implementations for functions/methods
11 // for analysis purposes.
13 //===----------------------------------------------------------------------===//
15 #include "clang/Analysis/BodyFarm.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/CXXInheritance.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"
22 #include "clang/AST/NestedNameSpecifier.h"
23 #include "clang/Analysis/CodeInjector.h"
24 #include "clang/Basic/OperatorKinds.h"
25 #include "llvm/ADT/StringSwitch.h"
26 #include "llvm/Support/Debug.h"
28 #define DEBUG_TYPE "body-farm"
30 using namespace clang;
32 //===----------------------------------------------------------------------===//
33 // Helper creation functions for constructing faux ASTs.
34 //===----------------------------------------------------------------------===//
36 static bool isDispatchBlock(QualType Ty) {
37 // Is it a block pointer?
38 const BlockPointerType *BPT = Ty->getAs<BlockPointerType>();
42 // Check if the block pointer type takes no arguments and
44 const FunctionProtoType *FT =
45 BPT->getPointeeType()->getAs<FunctionProtoType>();
46 return FT && FT->getReturnType()->isVoidType() && FT->getNumParams() == 0;
52 ASTMaker(ASTContext &C) : C(C) {}
54 /// Create a new BinaryOperator representing a simple assignment.
55 BinaryOperator *makeAssignment(const Expr *LHS, const Expr *RHS, QualType Ty);
57 /// Create a new BinaryOperator representing a comparison.
58 BinaryOperator *makeComparison(const Expr *LHS, const Expr *RHS,
59 BinaryOperator::Opcode Op);
61 /// Create a new compound stmt using the provided statements.
62 CompoundStmt *makeCompound(ArrayRef<Stmt*>);
64 /// Create a new DeclRefExpr for the referenced variable.
65 DeclRefExpr *makeDeclRefExpr(const VarDecl *D,
66 bool RefersToEnclosingVariableOrCapture = false);
68 /// Create a new UnaryOperator representing a dereference.
69 UnaryOperator *makeDereference(const Expr *Arg, QualType Ty);
71 /// Create an implicit cast for an integer conversion.
72 Expr *makeIntegralCast(const Expr *Arg, QualType Ty);
74 /// Create an implicit cast to a builtin boolean type.
75 ImplicitCastExpr *makeIntegralCastToBoolean(const Expr *Arg);
77 /// Create an implicit cast for lvalue-to-rvaluate conversions.
78 ImplicitCastExpr *makeLvalueToRvalue(const Expr *Arg, QualType Ty);
80 /// Make RValue out of variable declaration, creating a temporary
81 /// DeclRefExpr in the process.
83 makeLvalueToRvalue(const VarDecl *Decl,
84 bool RefersToEnclosingVariableOrCapture = false);
86 /// Create an implicit cast of the given type.
87 ImplicitCastExpr *makeImplicitCast(const Expr *Arg, QualType Ty,
88 CastKind CK = CK_LValueToRValue);
90 /// Create an Objective-C bool literal.
91 ObjCBoolLiteralExpr *makeObjCBool(bool Val);
93 /// Create an Objective-C ivar reference.
94 ObjCIvarRefExpr *makeObjCIvarRef(const Expr *Base, const ObjCIvarDecl *IVar);
96 /// Create a Return statement.
97 ReturnStmt *makeReturn(const Expr *RetVal);
99 /// Create an integer literal expression of the given type.
100 IntegerLiteral *makeIntegerLiteral(uint64_t Value, QualType Ty);
102 /// Create a member expression.
103 MemberExpr *makeMemberExpression(Expr *base, ValueDecl *MemberDecl,
104 bool IsArrow = false,
105 ExprValueKind ValueKind = VK_LValue);
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);
116 BinaryOperator *ASTMaker::makeAssignment(const Expr *LHS, const Expr *RHS,
118 return new (C) BinaryOperator(const_cast<Expr*>(LHS), const_cast<Expr*>(RHS),
119 BO_Assign, Ty, VK_RValue,
120 OK_Ordinary, SourceLocation(), FPOptions());
123 BinaryOperator *ASTMaker::makeComparison(const Expr *LHS, const Expr *RHS,
124 BinaryOperator::Opcode Op) {
125 assert(BinaryOperator::isLogicalOp(Op) ||
126 BinaryOperator::isComparisonOp(Op));
127 return new (C) BinaryOperator(const_cast<Expr*>(LHS),
128 const_cast<Expr*>(RHS),
130 C.getLogicalOperationType(),
132 OK_Ordinary, SourceLocation(), FPOptions());
135 CompoundStmt *ASTMaker::makeCompound(ArrayRef<Stmt *> Stmts) {
136 return new (C) CompoundStmt(C, Stmts, SourceLocation(), SourceLocation());
139 DeclRefExpr *ASTMaker::makeDeclRefExpr(
141 bool RefersToEnclosingVariableOrCapture) {
142 QualType Type = D->getType().getNonReferenceType();
144 DeclRefExpr *DR = DeclRefExpr::Create(
145 C, NestedNameSpecifierLoc(), SourceLocation(), const_cast<VarDecl *>(D),
146 RefersToEnclosingVariableOrCapture, SourceLocation(), Type, VK_LValue);
150 UnaryOperator *ASTMaker::makeDereference(const Expr *Arg, QualType Ty) {
151 return new (C) UnaryOperator(const_cast<Expr*>(Arg), UO_Deref, Ty,
152 VK_LValue, OK_Ordinary, SourceLocation());
155 ImplicitCastExpr *ASTMaker::makeLvalueToRvalue(const Expr *Arg, QualType Ty) {
156 return makeImplicitCast(Arg, Ty, CK_LValueToRValue);
160 ASTMaker::makeLvalueToRvalue(const VarDecl *Arg,
161 bool RefersToEnclosingVariableOrCapture) {
162 QualType Type = Arg->getType().getNonReferenceType();
163 return makeLvalueToRvalue(makeDeclRefExpr(Arg,
164 RefersToEnclosingVariableOrCapture),
168 ImplicitCastExpr *ASTMaker::makeImplicitCast(const Expr *Arg, QualType Ty,
170 return ImplicitCastExpr::Create(C, Ty,
172 /* Expr=*/ const_cast<Expr *>(Arg),
173 /* CXXCastPath=*/ nullptr,
174 /* ExprValueKind=*/ VK_RValue);
177 Expr *ASTMaker::makeIntegralCast(const Expr *Arg, QualType Ty) {
178 if (Arg->getType() == Ty)
179 return const_cast<Expr*>(Arg);
181 return ImplicitCastExpr::Create(C, Ty, CK_IntegralCast,
182 const_cast<Expr*>(Arg), nullptr, VK_RValue);
185 ImplicitCastExpr *ASTMaker::makeIntegralCastToBoolean(const Expr *Arg) {
186 return ImplicitCastExpr::Create(C, C.BoolTy, CK_IntegralToBoolean,
187 const_cast<Expr*>(Arg), nullptr, VK_RValue);
190 ObjCBoolLiteralExpr *ASTMaker::makeObjCBool(bool Val) {
191 QualType Ty = C.getBOOLDecl() ? C.getBOOLType() : C.ObjCBuiltinBoolTy;
192 return new (C) ObjCBoolLiteralExpr(Val, Ty, SourceLocation());
195 ObjCIvarRefExpr *ASTMaker::makeObjCIvarRef(const Expr *Base,
196 const ObjCIvarDecl *IVar) {
197 return new (C) ObjCIvarRefExpr(const_cast<ObjCIvarDecl*>(IVar),
198 IVar->getType(), SourceLocation(),
199 SourceLocation(), const_cast<Expr*>(Base),
200 /*arrow=*/true, /*free=*/false);
204 ReturnStmt *ASTMaker::makeReturn(const Expr *RetVal) {
205 return new (C) ReturnStmt(SourceLocation(), const_cast<Expr*>(RetVal),
209 IntegerLiteral *ASTMaker::makeIntegerLiteral(uint64_t Value, QualType Ty) {
210 llvm::APInt APValue = llvm::APInt(C.getTypeSize(Ty), Value);
211 return IntegerLiteral::Create(C, APValue, Ty, SourceLocation());
214 MemberExpr *ASTMaker::makeMemberExpression(Expr *base, ValueDecl *MemberDecl,
216 ExprValueKind ValueKind) {
218 DeclAccessPair FoundDecl = DeclAccessPair::make(MemberDecl, AS_public);
219 return MemberExpr::Create(
220 C, base, IsArrow, SourceLocation(), NestedNameSpecifierLoc(),
221 SourceLocation(), MemberDecl, FoundDecl,
222 DeclarationNameInfo(MemberDecl->getDeclName(), SourceLocation()),
223 /* TemplateArgumentListInfo=*/ nullptr, MemberDecl->getType(), ValueKind,
227 ValueDecl *ASTMaker::findMemberField(const RecordDecl *RD, StringRef Name) {
230 /* FindAmbiguities=*/false,
231 /* RecordPaths=*/false,
232 /* DetectVirtual=*/ false);
233 const IdentifierInfo &II = C.Idents.get(Name);
234 DeclarationName DeclName = C.DeclarationNames.getIdentifier(&II);
236 DeclContextLookupResult Decls = RD->lookup(DeclName);
237 for (NamedDecl *FoundDecl : Decls)
238 if (!FoundDecl->getDeclContext()->isFunctionOrMethod())
239 return cast<ValueDecl>(FoundDecl);
244 //===----------------------------------------------------------------------===//
245 // Creation functions for faux ASTs.
246 //===----------------------------------------------------------------------===//
248 typedef Stmt *(*FunctionFarmer)(ASTContext &C, const FunctionDecl *D);
250 static CallExpr *create_call_once_funcptr_call(ASTContext &C, ASTMaker M,
251 const ParmVarDecl *Callback,
252 ArrayRef<Expr *> CallArgs) {
254 QualType Ty = Callback->getType();
255 DeclRefExpr *Call = M.makeDeclRefExpr(Callback);
257 if (Ty->isRValueReferenceType()) {
258 CK = CK_LValueToRValue;
260 assert(Ty->isLValueReferenceType());
261 CK = CK_FunctionToPointerDecay;
262 Ty = C.getPointerType(Ty.getNonReferenceType());
266 CallExpr(C, M.makeImplicitCast(Call, Ty.getNonReferenceType(), CK),
268 /*QualType=*/C.VoidTy,
269 /*ExprValueType=*/VK_RValue,
270 /*SourceLocation=*/SourceLocation());
273 static CallExpr *create_call_once_lambda_call(ASTContext &C, ASTMaker M,
274 const ParmVarDecl *Callback,
275 CXXRecordDecl *CallbackDecl,
276 ArrayRef<Expr *> CallArgs) {
277 assert(CallbackDecl != nullptr);
278 assert(CallbackDecl->isLambda());
279 FunctionDecl *callOperatorDecl = CallbackDecl->getLambdaCallOperator();
280 assert(callOperatorDecl != nullptr);
282 DeclRefExpr *callOperatorDeclRef =
283 DeclRefExpr::Create(/* Ctx =*/ C,
284 /* QualifierLoc =*/ NestedNameSpecifierLoc(),
285 /* TemplateKWLoc =*/ SourceLocation(),
286 const_cast<FunctionDecl *>(callOperatorDecl),
287 /* RefersToEnclosingVariableOrCapture=*/ false,
288 /* NameLoc =*/ SourceLocation(),
289 /* T =*/ callOperatorDecl->getType(),
290 /* VK =*/ VK_LValue);
293 CXXOperatorCallExpr(/*AstContext=*/C, OO_Call, callOperatorDeclRef,
295 /*QualType=*/C.VoidTy,
296 /*ExprValueType=*/VK_RValue,
297 /*SourceLocation=*/SourceLocation(), FPOptions());
300 /// Create a fake body for std::call_once.
301 /// Emulates the following function body:
304 /// typedef struct once_flag_s {
305 /// unsigned long __state = 0;
307 /// template<class Callable>
308 /// void call_once(once_flag& o, Callable func) {
309 /// if (!o.__state) {
315 static Stmt *create_call_once(ASTContext &C, const FunctionDecl *D) {
316 DEBUG(llvm::dbgs() << "Generating body for call_once\n");
318 // We need at least two parameters.
319 if (D->param_size() < 2)
324 const ParmVarDecl *Flag = D->getParamDecl(0);
325 const ParmVarDecl *Callback = D->getParamDecl(1);
327 if (!Callback->getType()->isReferenceType()) {
328 llvm::dbgs() << "libcxx03 std::call_once implementation, skipping.\n";
331 if (!Flag->getType()->isReferenceType()) {
332 llvm::dbgs() << "unknown std::call_once implementation, skipping.\n";
336 QualType CallbackType = Callback->getType().getNonReferenceType();
338 // Nullable pointer, non-null iff function is a CXXRecordDecl.
339 CXXRecordDecl *CallbackRecordDecl = CallbackType->getAsCXXRecordDecl();
340 QualType FlagType = Flag->getType().getNonReferenceType();
341 auto *FlagRecordDecl = dyn_cast_or_null<RecordDecl>(FlagType->getAsTagDecl());
343 if (!FlagRecordDecl) {
344 DEBUG(llvm::dbgs() << "Flag field is not a record: "
345 << "unknown std::call_once implementation, "
346 << "ignoring the call.\n");
350 // We initially assume libc++ implementation of call_once,
351 // where the once_flag struct has a field `__state_`.
352 ValueDecl *FlagFieldDecl = M.findMemberField(FlagRecordDecl, "__state_");
354 // Otherwise, try libstdc++ implementation, with a field
356 if (!FlagFieldDecl) {
357 FlagFieldDecl = M.findMemberField(FlagRecordDecl, "_M_once");
360 if (!FlagFieldDecl) {
361 DEBUG(llvm::dbgs() << "No field _M_once or __state_ found on "
362 << "std::once_flag struct: unknown std::call_once "
363 << "implementation, ignoring the call.");
367 bool isLambdaCall = CallbackRecordDecl && CallbackRecordDecl->isLambda();
368 if (CallbackRecordDecl && !isLambdaCall) {
369 DEBUG(llvm::dbgs() << "Not supported: synthesizing body for functors when "
370 << "body farming std::call_once, ignoring the call.");
374 SmallVector<Expr *, 5> CallArgs;
375 const FunctionProtoType *CallbackFunctionType;
378 // Lambda requires callback itself inserted as a first parameter.
380 M.makeDeclRefExpr(Callback,
381 /* RefersToEnclosingVariableOrCapture=*/ true));
382 CallbackFunctionType = CallbackRecordDecl->getLambdaCallOperator()
384 ->getAs<FunctionProtoType>();
385 } else if (!CallbackType->getPointeeType().isNull()) {
386 CallbackFunctionType =
387 CallbackType->getPointeeType()->getAs<FunctionProtoType>();
389 CallbackFunctionType = CallbackType->getAs<FunctionProtoType>();
392 if (!CallbackFunctionType)
395 // First two arguments are used for the flag and for the callback.
396 if (D->getNumParams() != CallbackFunctionType->getNumParams() + 2) {
397 DEBUG(llvm::dbgs() << "Types of params of the callback do not match "
398 << "params passed to std::call_once, "
399 << "ignoring the call\n");
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
406 for (unsigned int ParamIdx = 2; ParamIdx < D->getNumParams(); ParamIdx++) {
407 const ParmVarDecl *PDecl = D->getParamDecl(ParamIdx);
408 Expr *ParamExpr = M.makeDeclRefExpr(PDecl);
409 if (!CallbackFunctionType->getParamType(ParamIdx - 2)->isReferenceType()) {
410 QualType PTy = PDecl->getType().getNonReferenceType();
411 ParamExpr = M.makeLvalueToRvalue(ParamExpr, PTy);
413 CallArgs.push_back(ParamExpr);
416 CallExpr *CallbackCall;
419 CallbackCall = create_call_once_lambda_call(C, M, Callback,
420 CallbackRecordDecl, CallArgs);
423 // Function pointer case.
424 CallbackCall = create_call_once_funcptr_call(C, M, Callback, CallArgs);
427 DeclRefExpr *FlagDecl =
428 M.makeDeclRefExpr(Flag,
429 /* RefersToEnclosingVariableOrCapture=*/true);
432 MemberExpr *Deref = M.makeMemberExpression(FlagDecl, FlagFieldDecl);
433 assert(Deref->isLValue());
434 QualType DerefType = Deref->getType();
436 // Negation predicate.
437 UnaryOperator *FlagCheck = new (C) UnaryOperator(
439 M.makeImplicitCast(M.makeLvalueToRvalue(Deref, DerefType), DerefType,
440 CK_IntegralToBoolean),
442 /* QualType=*/ C.IntTy,
443 /* ExprValueKind=*/ VK_RValue,
444 /* ExprObjectKind=*/ OK_Ordinary, SourceLocation());
446 // Create assignment.
447 BinaryOperator *FlagAssignment = M.makeAssignment(
448 Deref, M.makeIntegralCast(M.makeIntegerLiteral(1, C.IntTy), DerefType),
451 IfStmt *Out = new (C)
452 IfStmt(C, SourceLocation(),
453 /* IsConstexpr=*/ false,
456 /* cond=*/ FlagCheck,
457 /* then=*/ M.makeCompound({CallbackCall, FlagAssignment}));
462 /// Create a fake body for dispatch_once.
463 static Stmt *create_dispatch_once(ASTContext &C, const FunctionDecl *D) {
464 // Check if we have at least two parameters.
465 if (D->param_size() != 2)
468 // Check if the first parameter is a pointer to integer type.
469 const ParmVarDecl *Predicate = D->getParamDecl(0);
470 QualType PredicateQPtrTy = Predicate->getType();
471 const PointerType *PredicatePtrTy = PredicateQPtrTy->getAs<PointerType>();
474 QualType PredicateTy = PredicatePtrTy->getPointeeType();
475 if (!PredicateTy->isIntegerType())
478 // Check if the second parameter is the proper block type.
479 const ParmVarDecl *Block = D->getParamDecl(1);
480 QualType Ty = Block->getType();
481 if (!isDispatchBlock(Ty))
484 // Everything checks out. Create a fakse body that checks the predicate,
485 // sets it, and calls the block. Basically, an AST dump of:
487 // void dispatch_once(dispatch_once_t *predicate, dispatch_block_t block) {
488 // if (*predicate != ~0l) {
496 // (1) Create the call.
497 CallExpr *CE = new (C) CallExpr(
499 /*StmtClass=*/M.makeLvalueToRvalue(/*Expr=*/Block),
501 /*QualType=*/C.VoidTy,
502 /*ExprValueType=*/VK_RValue,
503 /*SourceLocation=*/SourceLocation());
505 // (2) Create the assignment to the predicate.
507 new (C) UnaryOperator(M.makeIntegerLiteral(0, C.LongTy), UO_Not, C.LongTy,
508 VK_RValue, OK_Ordinary, SourceLocation());
513 M.makeLvalueToRvalue(
514 M.makeDeclRefExpr(Predicate), PredicateQPtrTy),
516 M.makeIntegralCast(DoneValue, PredicateTy),
519 // (3) Create the compound statement.
520 Stmt *Stmts[] = { B, CE };
521 CompoundStmt *CS = M.makeCompound(Stmts);
523 // (4) Create the 'if' condition.
524 ImplicitCastExpr *LValToRval =
525 M.makeLvalueToRvalue(
527 M.makeLvalueToRvalue(
528 M.makeDeclRefExpr(Predicate),
533 Expr *GuardCondition = M.makeComparison(LValToRval, DoneValue, BO_NE);
534 // (5) Create the 'if' statement.
535 IfStmt *If = new (C) IfStmt(C, SourceLocation(),
536 /* IsConstexpr=*/ false,
539 /* cond=*/ GuardCondition,
544 /// Create a fake body for dispatch_sync.
545 static Stmt *create_dispatch_sync(ASTContext &C, const FunctionDecl *D) {
546 // Check if we have at least two parameters.
547 if (D->param_size() != 2)
550 // Check if the second parameter is a block.
551 const ParmVarDecl *PV = D->getParamDecl(1);
552 QualType Ty = PV->getType();
553 if (!isDispatchBlock(Ty))
556 // Everything checks out. Create a fake body that just calls the block.
557 // This is basically just an AST dump of:
559 // void dispatch_sync(dispatch_queue_t queue, void (^block)(void)) {
564 DeclRefExpr *DR = M.makeDeclRefExpr(PV);
565 ImplicitCastExpr *ICE = M.makeLvalueToRvalue(DR, Ty);
566 CallExpr *CE = new (C) CallExpr(C, ICE, None, C.VoidTy, VK_RValue,
571 static Stmt *create_OSAtomicCompareAndSwap(ASTContext &C, const FunctionDecl *D)
573 // There are exactly 3 arguments.
574 if (D->param_size() != 3)
578 // _Bool OSAtomicCompareAndSwapPtr(void *__oldValue,
580 // void * volatile *__theValue)
582 // if (oldValue == *theValue) {
583 // *theValue = newValue;
588 QualType ResultTy = D->getReturnType();
589 bool isBoolean = ResultTy->isBooleanType();
590 if (!isBoolean && !ResultTy->isIntegralType(C))
593 const ParmVarDecl *OldValue = D->getParamDecl(0);
594 QualType OldValueTy = OldValue->getType();
596 const ParmVarDecl *NewValue = D->getParamDecl(1);
597 QualType NewValueTy = NewValue->getType();
599 assert(OldValueTy == NewValueTy);
601 const ParmVarDecl *TheValue = D->getParamDecl(2);
602 QualType TheValueTy = TheValue->getType();
603 const PointerType *PT = TheValueTy->getAs<PointerType>();
606 QualType PointeeTy = PT->getPointeeType();
609 // Construct the comparison.
612 M.makeLvalueToRvalue(M.makeDeclRefExpr(OldValue), OldValueTy),
613 M.makeLvalueToRvalue(
615 M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy),
620 // Construct the body of the IfStmt.
625 M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy),
627 M.makeLvalueToRvalue(M.makeDeclRefExpr(NewValue), NewValueTy),
630 Expr *BoolVal = M.makeObjCBool(true);
631 Expr *RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal)
632 : M.makeIntegralCast(BoolVal, ResultTy);
633 Stmts[1] = M.makeReturn(RetVal);
634 CompoundStmt *Body = M.makeCompound(Stmts);
636 // Construct the else clause.
637 BoolVal = M.makeObjCBool(false);
638 RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal)
639 : M.makeIntegralCast(BoolVal, ResultTy);
640 Stmt *Else = M.makeReturn(RetVal);
642 /// Construct the If.
643 Stmt *If = new (C) IfStmt(C, SourceLocation(), false, nullptr, nullptr,
644 Comparison, Body, SourceLocation(), Else);
649 Stmt *BodyFarm::getBody(const FunctionDecl *D) {
650 D = D->getCanonicalDecl();
652 Optional<Stmt *> &Val = Bodies[D];
654 return Val.getValue();
658 if (D->getIdentifier() == nullptr)
661 StringRef Name = D->getName();
667 if (Name.startswith("OSAtomicCompareAndSwap") ||
668 Name.startswith("objc_atomicCompareAndSwap")) {
669 FF = create_OSAtomicCompareAndSwap;
670 } else if (Name == "call_once" && D->getDeclContext()->isStdNamespace()) {
671 FF = create_call_once;
673 FF = llvm::StringSwitch<FunctionFarmer>(Name)
674 .Case("dispatch_sync", create_dispatch_sync)
675 .Case("dispatch_once", create_dispatch_once)
679 if (FF) { Val = FF(C, D); }
680 else if (Injector) { Val = Injector->getBody(D); }
681 return Val.getValue();
684 static const ObjCIvarDecl *findBackingIvar(const ObjCPropertyDecl *Prop) {
685 const ObjCIvarDecl *IVar = Prop->getPropertyIvarDecl();
690 // When a readonly property is shadowed in a class extensions with a
691 // a readwrite property, the instance variable belongs to the shadowing
692 // property rather than the shadowed property. If there is no instance
693 // variable on a readonly property, check to see whether the property is
694 // shadowed and if so try to get the instance variable from shadowing
696 if (!Prop->isReadOnly())
699 auto *Container = cast<ObjCContainerDecl>(Prop->getDeclContext());
700 const ObjCInterfaceDecl *PrimaryInterface = nullptr;
701 if (auto *InterfaceDecl = dyn_cast<ObjCInterfaceDecl>(Container)) {
702 PrimaryInterface = InterfaceDecl;
703 } else if (auto *CategoryDecl = dyn_cast<ObjCCategoryDecl>(Container)) {
704 PrimaryInterface = CategoryDecl->getClassInterface();
705 } else if (auto *ImplDecl = dyn_cast<ObjCImplDecl>(Container)) {
706 PrimaryInterface = ImplDecl->getClassInterface();
711 // FindPropertyVisibleInPrimaryClass() looks first in class extensions, so it
712 // is guaranteed to find the shadowing property, if it exists, rather than
713 // the shadowed property.
714 auto *ShadowingProp = PrimaryInterface->FindPropertyVisibleInPrimaryClass(
715 Prop->getIdentifier(), Prop->getQueryKind());
716 if (ShadowingProp && ShadowingProp != Prop) {
717 IVar = ShadowingProp->getPropertyIvarDecl();
723 static Stmt *createObjCPropertyGetter(ASTContext &Ctx,
724 const ObjCPropertyDecl *Prop) {
725 // First, find the backing ivar.
726 const ObjCIvarDecl *IVar = findBackingIvar(Prop);
730 // Ignore weak variables, which have special behavior.
731 if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak)
734 // Look to see if Sema has synthesized a body for us. This happens in
735 // Objective-C++ because the return value may be a C++ class type with a
736 // non-trivial copy constructor. We can only do this if we can find the
737 // @synthesize for this property, though (or if we know it's been auto-
739 const ObjCImplementationDecl *ImplDecl =
740 IVar->getContainingInterface()->getImplementation();
742 for (const auto *I : ImplDecl->property_impls()) {
743 if (I->getPropertyDecl() != Prop)
746 if (I->getGetterCXXConstructor()) {
748 return M.makeReturn(I->getGetterCXXConstructor());
753 // Sanity check that the property is the same type as the ivar, or a
754 // reference to it, and that it is either an object pointer or trivially
756 if (!Ctx.hasSameUnqualifiedType(IVar->getType(),
757 Prop->getType().getNonReferenceType()))
759 if (!IVar->getType()->isObjCLifetimeType() &&
760 !IVar->getType().isTriviallyCopyableType(Ctx))
763 // Generate our body:
764 // return self->_ivar;
767 const VarDecl *selfVar = Prop->getGetterMethodDecl()->getSelfDecl();
773 M.makeLvalueToRvalue(
774 M.makeDeclRefExpr(selfVar),
778 if (!Prop->getType()->isReferenceType())
779 loadedIVar = M.makeLvalueToRvalue(loadedIVar, IVar->getType());
781 return M.makeReturn(loadedIVar);
784 Stmt *BodyFarm::getBody(const ObjCMethodDecl *D) {
785 // We currently only know how to synthesize property accessors.
786 if (!D->isPropertyAccessor())
789 D = D->getCanonicalDecl();
791 Optional<Stmt *> &Val = Bodies[D];
793 return Val.getValue();
796 const ObjCPropertyDecl *Prop = D->findPropertyDecl();
800 // For now, we only synthesize getters.
801 // Synthesizing setters would cause false negatives in the
802 // RetainCountChecker because the method body would bind the parameter
803 // to an instance variable, causing it to escape. This would prevent
804 // warning in the following common scenario:
806 // id foo = [[NSObject alloc] init];
807 // self.foo = foo; // We should warn that foo leaks here.
809 if (D->param_size() != 0)
812 Val = createObjCPropertyGetter(C, Prop);
814 return Val.getValue();