| //== BodyFarm.cpp - Factory for conjuring up fake bodies ----------*- C++ -*-// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // BodyFarm is a factory for creating faux implementations for functions/methods |
| // for analysis purposes. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Analysis/BodyFarm.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/CXXInheritance.h" |
| #include "clang/AST/Decl.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/ExprCXX.h" |
| #include "clang/AST/ExprObjC.h" |
| #include "clang/AST/NestedNameSpecifier.h" |
| #include "clang/Analysis/CodeInjector.h" |
| #include "clang/Basic/OperatorKinds.h" |
| #include "llvm/ADT/StringSwitch.h" |
| #include "llvm/Support/Debug.h" |
| |
| #define DEBUG_TYPE "body-farm" |
| |
| using namespace clang; |
| |
| //===----------------------------------------------------------------------===// |
| // Helper creation functions for constructing faux ASTs. |
| //===----------------------------------------------------------------------===// |
| |
| static bool isDispatchBlock(QualType Ty) { |
| // Is it a block pointer? |
| const BlockPointerType *BPT = Ty->getAs<BlockPointerType>(); |
| if (!BPT) |
| return false; |
| |
| // Check if the block pointer type takes no arguments and |
| // returns void. |
| const FunctionProtoType *FT = |
| BPT->getPointeeType()->getAs<FunctionProtoType>(); |
| return FT && FT->getReturnType()->isVoidType() && FT->getNumParams() == 0; |
| } |
| |
| namespace { |
| class ASTMaker { |
| public: |
| ASTMaker(ASTContext &C) : C(C) {} |
| |
| /// Create a new BinaryOperator representing a simple assignment. |
| BinaryOperator *makeAssignment(const Expr *LHS, const Expr *RHS, QualType Ty); |
| |
| /// Create a new BinaryOperator representing a comparison. |
| BinaryOperator *makeComparison(const Expr *LHS, const Expr *RHS, |
| BinaryOperator::Opcode Op); |
| |
| /// Create a new compound stmt using the provided statements. |
| CompoundStmt *makeCompound(ArrayRef<Stmt*>); |
| |
| /// Create a new DeclRefExpr for the referenced variable. |
| DeclRefExpr *makeDeclRefExpr(const VarDecl *D, |
| bool RefersToEnclosingVariableOrCapture = false); |
| |
| /// Create a new UnaryOperator representing a dereference. |
| UnaryOperator *makeDereference(const Expr *Arg, QualType Ty); |
| |
| /// Create an implicit cast for an integer conversion. |
| Expr *makeIntegralCast(const Expr *Arg, QualType Ty); |
| |
| /// Create an implicit cast to a builtin boolean type. |
| ImplicitCastExpr *makeIntegralCastToBoolean(const Expr *Arg); |
| |
| /// Create an implicit cast for lvalue-to-rvaluate conversions. |
| ImplicitCastExpr *makeLvalueToRvalue(const Expr *Arg, QualType Ty); |
| |
| /// Make RValue out of variable declaration, creating a temporary |
| /// DeclRefExpr in the process. |
| ImplicitCastExpr * |
| makeLvalueToRvalue(const VarDecl *Decl, |
| bool RefersToEnclosingVariableOrCapture = false); |
| |
| /// Create an implicit cast of the given type. |
| ImplicitCastExpr *makeImplicitCast(const Expr *Arg, QualType Ty, |
| CastKind CK = CK_LValueToRValue); |
| |
| /// Create an Objective-C bool literal. |
| ObjCBoolLiteralExpr *makeObjCBool(bool Val); |
| |
| /// Create an Objective-C ivar reference. |
| ObjCIvarRefExpr *makeObjCIvarRef(const Expr *Base, const ObjCIvarDecl *IVar); |
| |
| /// Create a Return statement. |
| ReturnStmt *makeReturn(const Expr *RetVal); |
| |
| /// Create an integer literal expression of the given type. |
| IntegerLiteral *makeIntegerLiteral(uint64_t Value, QualType Ty); |
| |
| /// Create a member expression. |
| MemberExpr *makeMemberExpression(Expr *base, ValueDecl *MemberDecl, |
| bool IsArrow = false, |
| ExprValueKind ValueKind = VK_LValue); |
| |
| /// Returns a *first* member field of a record declaration with a given name. |
| /// \return an nullptr if no member with such a name exists. |
| ValueDecl *findMemberField(const RecordDecl *RD, StringRef Name); |
| |
| private: |
| ASTContext &C; |
| }; |
| } |
| |
| BinaryOperator *ASTMaker::makeAssignment(const Expr *LHS, const Expr *RHS, |
| QualType Ty) { |
| return new (C) BinaryOperator(const_cast<Expr*>(LHS), const_cast<Expr*>(RHS), |
| BO_Assign, Ty, VK_RValue, |
| OK_Ordinary, SourceLocation(), FPOptions()); |
| } |
| |
| BinaryOperator *ASTMaker::makeComparison(const Expr *LHS, const Expr *RHS, |
| BinaryOperator::Opcode Op) { |
| assert(BinaryOperator::isLogicalOp(Op) || |
| BinaryOperator::isComparisonOp(Op)); |
| return new (C) BinaryOperator(const_cast<Expr*>(LHS), |
| const_cast<Expr*>(RHS), |
| Op, |
| C.getLogicalOperationType(), |
| VK_RValue, |
| OK_Ordinary, SourceLocation(), FPOptions()); |
| } |
| |
| CompoundStmt *ASTMaker::makeCompound(ArrayRef<Stmt *> Stmts) { |
| return CompoundStmt::Create(C, Stmts, SourceLocation(), SourceLocation()); |
| } |
| |
| DeclRefExpr *ASTMaker::makeDeclRefExpr( |
| const VarDecl *D, |
| bool RefersToEnclosingVariableOrCapture) { |
| QualType Type = D->getType().getNonReferenceType(); |
| |
| DeclRefExpr *DR = DeclRefExpr::Create( |
| C, NestedNameSpecifierLoc(), SourceLocation(), const_cast<VarDecl *>(D), |
| RefersToEnclosingVariableOrCapture, SourceLocation(), Type, VK_LValue); |
| return DR; |
| } |
| |
| UnaryOperator *ASTMaker::makeDereference(const Expr *Arg, QualType Ty) { |
| return new (C) UnaryOperator(const_cast<Expr*>(Arg), UO_Deref, Ty, |
| VK_LValue, OK_Ordinary, SourceLocation(), |
| /*CanOverflow*/ false); |
| } |
| |
| ImplicitCastExpr *ASTMaker::makeLvalueToRvalue(const Expr *Arg, QualType Ty) { |
| return makeImplicitCast(Arg, Ty, CK_LValueToRValue); |
| } |
| |
| ImplicitCastExpr * |
| ASTMaker::makeLvalueToRvalue(const VarDecl *Arg, |
| bool RefersToEnclosingVariableOrCapture) { |
| QualType Type = Arg->getType().getNonReferenceType(); |
| return makeLvalueToRvalue(makeDeclRefExpr(Arg, |
| RefersToEnclosingVariableOrCapture), |
| Type); |
| } |
| |
| ImplicitCastExpr *ASTMaker::makeImplicitCast(const Expr *Arg, QualType Ty, |
| CastKind CK) { |
| return ImplicitCastExpr::Create(C, Ty, |
| /* CastKind=*/ CK, |
| /* Expr=*/ const_cast<Expr *>(Arg), |
| /* CXXCastPath=*/ nullptr, |
| /* ExprValueKind=*/ VK_RValue); |
| } |
| |
| Expr *ASTMaker::makeIntegralCast(const Expr *Arg, QualType Ty) { |
| if (Arg->getType() == Ty) |
| return const_cast<Expr*>(Arg); |
| |
| return ImplicitCastExpr::Create(C, Ty, CK_IntegralCast, |
| const_cast<Expr*>(Arg), nullptr, VK_RValue); |
| } |
| |
| ImplicitCastExpr *ASTMaker::makeIntegralCastToBoolean(const Expr *Arg) { |
| return ImplicitCastExpr::Create(C, C.BoolTy, CK_IntegralToBoolean, |
| const_cast<Expr*>(Arg), nullptr, VK_RValue); |
| } |
| |
| ObjCBoolLiteralExpr *ASTMaker::makeObjCBool(bool Val) { |
| QualType Ty = C.getBOOLDecl() ? C.getBOOLType() : C.ObjCBuiltinBoolTy; |
| return new (C) ObjCBoolLiteralExpr(Val, Ty, SourceLocation()); |
| } |
| |
| ObjCIvarRefExpr *ASTMaker::makeObjCIvarRef(const Expr *Base, |
| const ObjCIvarDecl *IVar) { |
| return new (C) ObjCIvarRefExpr(const_cast<ObjCIvarDecl*>(IVar), |
| IVar->getType(), SourceLocation(), |
| SourceLocation(), const_cast<Expr*>(Base), |
| /*arrow=*/true, /*free=*/false); |
| } |
| |
| ReturnStmt *ASTMaker::makeReturn(const Expr *RetVal) { |
| return ReturnStmt::Create(C, SourceLocation(), const_cast<Expr *>(RetVal), |
| /* NRVOCandidate=*/nullptr); |
| } |
| |
| IntegerLiteral *ASTMaker::makeIntegerLiteral(uint64_t Value, QualType Ty) { |
| llvm::APInt APValue = llvm::APInt(C.getTypeSize(Ty), Value); |
| return IntegerLiteral::Create(C, APValue, Ty, SourceLocation()); |
| } |
| |
| MemberExpr *ASTMaker::makeMemberExpression(Expr *base, ValueDecl *MemberDecl, |
| bool IsArrow, |
| ExprValueKind ValueKind) { |
| |
| DeclAccessPair FoundDecl = DeclAccessPair::make(MemberDecl, AS_public); |
| return MemberExpr::Create( |
| C, base, IsArrow, SourceLocation(), NestedNameSpecifierLoc(), |
| SourceLocation(), MemberDecl, FoundDecl, |
| DeclarationNameInfo(MemberDecl->getDeclName(), SourceLocation()), |
| /* TemplateArgumentListInfo=*/ nullptr, MemberDecl->getType(), ValueKind, |
| OK_Ordinary, NOUR_None); |
| } |
| |
| ValueDecl *ASTMaker::findMemberField(const RecordDecl *RD, StringRef Name) { |
| |
| CXXBasePaths Paths( |
| /* FindAmbiguities=*/false, |
| /* RecordPaths=*/false, |
| /* DetectVirtual=*/ false); |
| const IdentifierInfo &II = C.Idents.get(Name); |
| DeclarationName DeclName = C.DeclarationNames.getIdentifier(&II); |
| |
| DeclContextLookupResult Decls = RD->lookup(DeclName); |
| for (NamedDecl *FoundDecl : Decls) |
| if (!FoundDecl->getDeclContext()->isFunctionOrMethod()) |
| return cast<ValueDecl>(FoundDecl); |
| |
| return nullptr; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Creation functions for faux ASTs. |
| //===----------------------------------------------------------------------===// |
| |
| typedef Stmt *(*FunctionFarmer)(ASTContext &C, const FunctionDecl *D); |
| |
| static CallExpr *create_call_once_funcptr_call(ASTContext &C, ASTMaker M, |
| const ParmVarDecl *Callback, |
| ArrayRef<Expr *> CallArgs) { |
| |
| QualType Ty = Callback->getType(); |
| DeclRefExpr *Call = M.makeDeclRefExpr(Callback); |
| Expr *SubExpr; |
| if (Ty->isRValueReferenceType()) { |
| SubExpr = M.makeImplicitCast( |
| Call, Ty.getNonReferenceType(), CK_LValueToRValue); |
| } else if (Ty->isLValueReferenceType() && |
| Call->getType()->isFunctionType()) { |
| Ty = C.getPointerType(Ty.getNonReferenceType()); |
| SubExpr = M.makeImplicitCast(Call, Ty, CK_FunctionToPointerDecay); |
| } else if (Ty->isLValueReferenceType() |
| && Call->getType()->isPointerType() |
| && Call->getType()->getPointeeType()->isFunctionType()){ |
| SubExpr = Call; |
| } else { |
| llvm_unreachable("Unexpected state"); |
| } |
| |
| return CallExpr::Create(C, SubExpr, CallArgs, C.VoidTy, VK_RValue, |
| SourceLocation()); |
| } |
| |
| static CallExpr *create_call_once_lambda_call(ASTContext &C, ASTMaker M, |
| const ParmVarDecl *Callback, |
| CXXRecordDecl *CallbackDecl, |
| ArrayRef<Expr *> CallArgs) { |
| assert(CallbackDecl != nullptr); |
| assert(CallbackDecl->isLambda()); |
| FunctionDecl *callOperatorDecl = CallbackDecl->getLambdaCallOperator(); |
| assert(callOperatorDecl != nullptr); |
| |
| DeclRefExpr *callOperatorDeclRef = |
| DeclRefExpr::Create(/* Ctx =*/ C, |
| /* QualifierLoc =*/ NestedNameSpecifierLoc(), |
| /* TemplateKWLoc =*/ SourceLocation(), |
| const_cast<FunctionDecl *>(callOperatorDecl), |
| /* RefersToEnclosingVariableOrCapture=*/ false, |
| /* NameLoc =*/ SourceLocation(), |
| /* T =*/ callOperatorDecl->getType(), |
| /* VK =*/ VK_LValue); |
| |
| return CXXOperatorCallExpr::Create( |
| /*AstContext=*/C, OO_Call, callOperatorDeclRef, |
| /*Args=*/CallArgs, |
| /*QualType=*/C.VoidTy, |
| /*ExprValueType=*/VK_RValue, |
| /*SourceLocation=*/SourceLocation(), FPOptions()); |
| } |
| |
| /// Create a fake body for std::call_once. |
| /// Emulates the following function body: |
| /// |
| /// \code |
| /// typedef struct once_flag_s { |
| /// unsigned long __state = 0; |
| /// } once_flag; |
| /// template<class Callable> |
| /// void call_once(once_flag& o, Callable func) { |
| /// if (!o.__state) { |
| /// func(); |
| /// } |
| /// o.__state = 1; |
| /// } |
| /// \endcode |
| static Stmt *create_call_once(ASTContext &C, const FunctionDecl *D) { |
| LLVM_DEBUG(llvm::dbgs() << "Generating body for call_once\n"); |
| |
| // We need at least two parameters. |
| if (D->param_size() < 2) |
| return nullptr; |
| |
| ASTMaker M(C); |
| |
| const ParmVarDecl *Flag = D->getParamDecl(0); |
| const ParmVarDecl *Callback = D->getParamDecl(1); |
| |
| if (!Callback->getType()->isReferenceType()) { |
| llvm::dbgs() << "libcxx03 std::call_once implementation, skipping.\n"; |
| return nullptr; |
| } |
| if (!Flag->getType()->isReferenceType()) { |
| llvm::dbgs() << "unknown std::call_once implementation, skipping.\n"; |
| return nullptr; |
| } |
| |
| QualType CallbackType = Callback->getType().getNonReferenceType(); |
| |
| // Nullable pointer, non-null iff function is a CXXRecordDecl. |
| CXXRecordDecl *CallbackRecordDecl = CallbackType->getAsCXXRecordDecl(); |
| QualType FlagType = Flag->getType().getNonReferenceType(); |
| auto *FlagRecordDecl = FlagType->getAsRecordDecl(); |
| |
| if (!FlagRecordDecl) { |
| LLVM_DEBUG(llvm::dbgs() << "Flag field is not a record: " |
| << "unknown std::call_once implementation, " |
| << "ignoring the call.\n"); |
| return nullptr; |
| } |
| |
| // We initially assume libc++ implementation of call_once, |
| // where the once_flag struct has a field `__state_`. |
| ValueDecl *FlagFieldDecl = M.findMemberField(FlagRecordDecl, "__state_"); |
| |
| // Otherwise, try libstdc++ implementation, with a field |
| // `_M_once` |
| if (!FlagFieldDecl) { |
| FlagFieldDecl = M.findMemberField(FlagRecordDecl, "_M_once"); |
| } |
| |
| if (!FlagFieldDecl) { |
| LLVM_DEBUG(llvm::dbgs() << "No field _M_once or __state_ found on " |
| << "std::once_flag struct: unknown std::call_once " |
| << "implementation, ignoring the call."); |
| return nullptr; |
| } |
| |
| bool isLambdaCall = CallbackRecordDecl && CallbackRecordDecl->isLambda(); |
| if (CallbackRecordDecl && !isLambdaCall) { |
| LLVM_DEBUG(llvm::dbgs() |
| << "Not supported: synthesizing body for functors when " |
| << "body farming std::call_once, ignoring the call."); |
| return nullptr; |
| } |
| |
| SmallVector<Expr *, 5> CallArgs; |
| const FunctionProtoType *CallbackFunctionType; |
| if (isLambdaCall) { |
| |
| // Lambda requires callback itself inserted as a first parameter. |
| CallArgs.push_back( |
| M.makeDeclRefExpr(Callback, |
| /* RefersToEnclosingVariableOrCapture=*/ true)); |
| CallbackFunctionType = CallbackRecordDecl->getLambdaCallOperator() |
| ->getType() |
| ->getAs<FunctionProtoType>(); |
| } else if (!CallbackType->getPointeeType().isNull()) { |
| CallbackFunctionType = |
| CallbackType->getPointeeType()->getAs<FunctionProtoType>(); |
| } else { |
| CallbackFunctionType = CallbackType->getAs<FunctionProtoType>(); |
| } |
| |
| if (!CallbackFunctionType) |
| return nullptr; |
| |
| // First two arguments are used for the flag and for the callback. |
| if (D->getNumParams() != CallbackFunctionType->getNumParams() + 2) { |
| LLVM_DEBUG(llvm::dbgs() << "Types of params of the callback do not match " |
| << "params passed to std::call_once, " |
| << "ignoring the call\n"); |
| return nullptr; |
| } |
| |
| // All arguments past first two ones are passed to the callback, |
| // and we turn lvalues into rvalues if the argument is not passed by |
| // reference. |
| for (unsigned int ParamIdx = 2; ParamIdx < D->getNumParams(); ParamIdx++) { |
| const ParmVarDecl *PDecl = D->getParamDecl(ParamIdx); |
| assert(PDecl); |
| if (CallbackFunctionType->getParamType(ParamIdx - 2) |
| .getNonReferenceType() |
| .getCanonicalType() != |
| PDecl->getType().getNonReferenceType().getCanonicalType()) { |
| LLVM_DEBUG(llvm::dbgs() << "Types of params of the callback do not match " |
| << "params passed to std::call_once, " |
| << "ignoring the call\n"); |
| return nullptr; |
| } |
| Expr *ParamExpr = M.makeDeclRefExpr(PDecl); |
| if (!CallbackFunctionType->getParamType(ParamIdx - 2)->isReferenceType()) { |
| QualType PTy = PDecl->getType().getNonReferenceType(); |
| ParamExpr = M.makeLvalueToRvalue(ParamExpr, PTy); |
| } |
| CallArgs.push_back(ParamExpr); |
| } |
| |
| CallExpr *CallbackCall; |
| if (isLambdaCall) { |
| |
| CallbackCall = create_call_once_lambda_call(C, M, Callback, |
| CallbackRecordDecl, CallArgs); |
| } else { |
| |
| // Function pointer case. |
| CallbackCall = create_call_once_funcptr_call(C, M, Callback, CallArgs); |
| } |
| |
| DeclRefExpr *FlagDecl = |
| M.makeDeclRefExpr(Flag, |
| /* RefersToEnclosingVariableOrCapture=*/true); |
| |
| |
| MemberExpr *Deref = M.makeMemberExpression(FlagDecl, FlagFieldDecl); |
| assert(Deref->isLValue()); |
| QualType DerefType = Deref->getType(); |
| |
| // Negation predicate. |
| UnaryOperator *FlagCheck = new (C) UnaryOperator( |
| /* input=*/ |
| M.makeImplicitCast(M.makeLvalueToRvalue(Deref, DerefType), DerefType, |
| CK_IntegralToBoolean), |
| /* opc=*/ UO_LNot, |
| /* QualType=*/ C.IntTy, |
| /* ExprValueKind=*/ VK_RValue, |
| /* ExprObjectKind=*/ OK_Ordinary, SourceLocation(), |
| /* CanOverflow*/ false); |
| |
| // Create assignment. |
| BinaryOperator *FlagAssignment = M.makeAssignment( |
| Deref, M.makeIntegralCast(M.makeIntegerLiteral(1, C.IntTy), DerefType), |
| DerefType); |
| |
| auto *Out = |
| IfStmt::Create(C, SourceLocation(), |
| /* IsConstexpr=*/false, |
| /* Init=*/nullptr, |
| /* Var=*/nullptr, |
| /* Cond=*/FlagCheck, |
| /* Then=*/M.makeCompound({CallbackCall, FlagAssignment})); |
| |
| return Out; |
| } |
| |
| /// Create a fake body for dispatch_once. |
| static Stmt *create_dispatch_once(ASTContext &C, const FunctionDecl *D) { |
| // Check if we have at least two parameters. |
| if (D->param_size() != 2) |
| return nullptr; |
| |
| // Check if the first parameter is a pointer to integer type. |
| const ParmVarDecl *Predicate = D->getParamDecl(0); |
| QualType PredicateQPtrTy = Predicate->getType(); |
| const PointerType *PredicatePtrTy = PredicateQPtrTy->getAs<PointerType>(); |
| if (!PredicatePtrTy) |
| return nullptr; |
| QualType PredicateTy = PredicatePtrTy->getPointeeType(); |
| if (!PredicateTy->isIntegerType()) |
| return nullptr; |
| |
| // Check if the second parameter is the proper block type. |
| const ParmVarDecl *Block = D->getParamDecl(1); |
| QualType Ty = Block->getType(); |
| if (!isDispatchBlock(Ty)) |
| return nullptr; |
| |
| // Everything checks out. Create a fakse body that checks the predicate, |
| // sets it, and calls the block. Basically, an AST dump of: |
| // |
| // void dispatch_once(dispatch_once_t *predicate, dispatch_block_t block) { |
| // if (*predicate != ~0l) { |
| // *predicate = ~0l; |
| // block(); |
| // } |
| // } |
| |
| ASTMaker M(C); |
| |
| // (1) Create the call. |
| CallExpr *CE = CallExpr::Create( |
| /*ASTContext=*/C, |
| /*StmtClass=*/M.makeLvalueToRvalue(/*Expr=*/Block), |
| /*Args=*/None, |
| /*QualType=*/C.VoidTy, |
| /*ExprValueType=*/VK_RValue, |
| /*SourceLocation=*/SourceLocation()); |
| |
| // (2) Create the assignment to the predicate. |
| Expr *DoneValue = |
| new (C) UnaryOperator(M.makeIntegerLiteral(0, C.LongTy), UO_Not, C.LongTy, |
| VK_RValue, OK_Ordinary, SourceLocation(), |
| /*CanOverflow*/false); |
| |
| BinaryOperator *B = |
| M.makeAssignment( |
| M.makeDereference( |
| M.makeLvalueToRvalue( |
| M.makeDeclRefExpr(Predicate), PredicateQPtrTy), |
| PredicateTy), |
| M.makeIntegralCast(DoneValue, PredicateTy), |
| PredicateTy); |
| |
| // (3) Create the compound statement. |
| Stmt *Stmts[] = { B, CE }; |
| CompoundStmt *CS = M.makeCompound(Stmts); |
| |
| // (4) Create the 'if' condition. |
| ImplicitCastExpr *LValToRval = |
| M.makeLvalueToRvalue( |
| M.makeDereference( |
| M.makeLvalueToRvalue( |
| M.makeDeclRefExpr(Predicate), |
| PredicateQPtrTy), |
| PredicateTy), |
| PredicateTy); |
| |
| Expr *GuardCondition = M.makeComparison(LValToRval, DoneValue, BO_NE); |
| // (5) Create the 'if' statement. |
| auto *If = IfStmt::Create(C, SourceLocation(), |
| /* IsConstexpr=*/false, |
| /* Init=*/nullptr, |
| /* Var=*/nullptr, |
| /* Cond=*/GuardCondition, |
| /* Then=*/CS); |
| return If; |
| } |
| |
| /// Create a fake body for dispatch_sync. |
| static Stmt *create_dispatch_sync(ASTContext &C, const FunctionDecl *D) { |
| // Check if we have at least two parameters. |
| if (D->param_size() != 2) |
| return nullptr; |
| |
| // Check if the second parameter is a block. |
| const ParmVarDecl *PV = D->getParamDecl(1); |
| QualType Ty = PV->getType(); |
| if (!isDispatchBlock(Ty)) |
| return nullptr; |
| |
| // Everything checks out. Create a fake body that just calls the block. |
| // This is basically just an AST dump of: |
| // |
| // void dispatch_sync(dispatch_queue_t queue, void (^block)(void)) { |
| // block(); |
| // } |
| // |
| ASTMaker M(C); |
| DeclRefExpr *DR = M.makeDeclRefExpr(PV); |
| ImplicitCastExpr *ICE = M.makeLvalueToRvalue(DR, Ty); |
| CallExpr *CE = |
| CallExpr::Create(C, ICE, None, C.VoidTy, VK_RValue, SourceLocation()); |
| return CE; |
| } |
| |
| static Stmt *create_OSAtomicCompareAndSwap(ASTContext &C, const FunctionDecl *D) |
| { |
| // There are exactly 3 arguments. |
| if (D->param_size() != 3) |
| return nullptr; |
| |
| // Signature: |
| // _Bool OSAtomicCompareAndSwapPtr(void *__oldValue, |
| // void *__newValue, |
| // void * volatile *__theValue) |
| // Generate body: |
| // if (oldValue == *theValue) { |
| // *theValue = newValue; |
| // return YES; |
| // } |
| // else return NO; |
| |
| QualType ResultTy = D->getReturnType(); |
| bool isBoolean = ResultTy->isBooleanType(); |
| if (!isBoolean && !ResultTy->isIntegralType(C)) |
| return nullptr; |
| |
| const ParmVarDecl *OldValue = D->getParamDecl(0); |
| QualType OldValueTy = OldValue->getType(); |
| |
| const ParmVarDecl *NewValue = D->getParamDecl(1); |
| QualType NewValueTy = NewValue->getType(); |
| |
| assert(OldValueTy == NewValueTy); |
| |
| const ParmVarDecl *TheValue = D->getParamDecl(2); |
| QualType TheValueTy = TheValue->getType(); |
| const PointerType *PT = TheValueTy->getAs<PointerType>(); |
| if (!PT) |
| return nullptr; |
| QualType PointeeTy = PT->getPointeeType(); |
| |
| ASTMaker M(C); |
| // Construct the comparison. |
| Expr *Comparison = |
| M.makeComparison( |
| M.makeLvalueToRvalue(M.makeDeclRefExpr(OldValue), OldValueTy), |
| M.makeLvalueToRvalue( |
| M.makeDereference( |
| M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy), |
| PointeeTy), |
| PointeeTy), |
| BO_EQ); |
| |
| // Construct the body of the IfStmt. |
| Stmt *Stmts[2]; |
| Stmts[0] = |
| M.makeAssignment( |
| M.makeDereference( |
| M.makeLvalueToRvalue(M.makeDeclRefExpr(TheValue), TheValueTy), |
| PointeeTy), |
| M.makeLvalueToRvalue(M.makeDeclRefExpr(NewValue), NewValueTy), |
| NewValueTy); |
| |
| Expr *BoolVal = M.makeObjCBool(true); |
| Expr *RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal) |
| : M.makeIntegralCast(BoolVal, ResultTy); |
| Stmts[1] = M.makeReturn(RetVal); |
| CompoundStmt *Body = M.makeCompound(Stmts); |
| |
| // Construct the else clause. |
| BoolVal = M.makeObjCBool(false); |
| RetVal = isBoolean ? M.makeIntegralCastToBoolean(BoolVal) |
| : M.makeIntegralCast(BoolVal, ResultTy); |
| Stmt *Else = M.makeReturn(RetVal); |
| |
| /// Construct the If. |
| auto *If = IfStmt::Create(C, SourceLocation(), |
| /* IsConstexpr=*/false, |
| /* Init=*/nullptr, |
| /* Var=*/nullptr, Comparison, Body, |
| SourceLocation(), Else); |
| |
| return If; |
| } |
| |
| Stmt *BodyFarm::getBody(const FunctionDecl *D) { |
| Optional<Stmt *> &Val = Bodies[D]; |
| if (Val.hasValue()) |
| return Val.getValue(); |
| |
| Val = nullptr; |
| |
| if (D->getIdentifier() == nullptr) |
| return nullptr; |
| |
| StringRef Name = D->getName(); |
| if (Name.empty()) |
| return nullptr; |
| |
| FunctionFarmer FF; |
| |
| if (Name.startswith("OSAtomicCompareAndSwap") || |
| Name.startswith("objc_atomicCompareAndSwap")) { |
| FF = create_OSAtomicCompareAndSwap; |
| } else if (Name == "call_once" && D->getDeclContext()->isStdNamespace()) { |
| FF = create_call_once; |
| } else { |
| FF = llvm::StringSwitch<FunctionFarmer>(Name) |
| .Case("dispatch_sync", create_dispatch_sync) |
| .Case("dispatch_once", create_dispatch_once) |
| .Default(nullptr); |
| } |
| |
| if (FF) { Val = FF(C, D); } |
| else if (Injector) { Val = Injector->getBody(D); } |
| return Val.getValue(); |
| } |
| |
| static const ObjCIvarDecl *findBackingIvar(const ObjCPropertyDecl *Prop) { |
| const ObjCIvarDecl *IVar = Prop->getPropertyIvarDecl(); |
| |
| if (IVar) |
| return IVar; |
| |
| // When a readonly property is shadowed in a class extensions with a |
| // a readwrite property, the instance variable belongs to the shadowing |
| // property rather than the shadowed property. If there is no instance |
| // variable on a readonly property, check to see whether the property is |
| // shadowed and if so try to get the instance variable from shadowing |
| // property. |
| if (!Prop->isReadOnly()) |
| return nullptr; |
| |
| auto *Container = cast<ObjCContainerDecl>(Prop->getDeclContext()); |
| const ObjCInterfaceDecl *PrimaryInterface = nullptr; |
| if (auto *InterfaceDecl = dyn_cast<ObjCInterfaceDecl>(Container)) { |
| PrimaryInterface = InterfaceDecl; |
| } else if (auto *CategoryDecl = dyn_cast<ObjCCategoryDecl>(Container)) { |
| PrimaryInterface = CategoryDecl->getClassInterface(); |
| } else if (auto *ImplDecl = dyn_cast<ObjCImplDecl>(Container)) { |
| PrimaryInterface = ImplDecl->getClassInterface(); |
| } else { |
| return nullptr; |
| } |
| |
| // FindPropertyVisibleInPrimaryClass() looks first in class extensions, so it |
| // is guaranteed to find the shadowing property, if it exists, rather than |
| // the shadowed property. |
| auto *ShadowingProp = PrimaryInterface->FindPropertyVisibleInPrimaryClass( |
| Prop->getIdentifier(), Prop->getQueryKind()); |
| if (ShadowingProp && ShadowingProp != Prop) { |
| IVar = ShadowingProp->getPropertyIvarDecl(); |
| } |
| |
| return IVar; |
| } |
| |
| static Stmt *createObjCPropertyGetter(ASTContext &Ctx, |
| const ObjCPropertyDecl *Prop) { |
| // First, find the backing ivar. |
| const ObjCIvarDecl *IVar = findBackingIvar(Prop); |
| if (!IVar) |
| return nullptr; |
| |
| // Ignore weak variables, which have special behavior. |
| if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak) |
| return nullptr; |
| |
| // Look to see if Sema has synthesized a body for us. This happens in |
| // Objective-C++ because the return value may be a C++ class type with a |
| // non-trivial copy constructor. We can only do this if we can find the |
| // @synthesize for this property, though (or if we know it's been auto- |
| // synthesized). |
| const ObjCImplementationDecl *ImplDecl = |
| IVar->getContainingInterface()->getImplementation(); |
| if (ImplDecl) { |
| for (const auto *I : ImplDecl->property_impls()) { |
| if (I->getPropertyDecl() != Prop) |
| continue; |
| |
| if (I->getGetterCXXConstructor()) { |
| ASTMaker M(Ctx); |
| return M.makeReturn(I->getGetterCXXConstructor()); |
| } |
| } |
| } |
| |
| // Sanity check that the property is the same type as the ivar, or a |
| // reference to it, and that it is either an object pointer or trivially |
| // copyable. |
| if (!Ctx.hasSameUnqualifiedType(IVar->getType(), |
| Prop->getType().getNonReferenceType())) |
| return nullptr; |
| if (!IVar->getType()->isObjCLifetimeType() && |
| !IVar->getType().isTriviallyCopyableType(Ctx)) |
| return nullptr; |
| |
| // Generate our body: |
| // return self->_ivar; |
| ASTMaker M(Ctx); |
| |
| const VarDecl *selfVar = Prop->getGetterMethodDecl()->getSelfDecl(); |
| if (!selfVar) |
| return nullptr; |
| |
| Expr *loadedIVar = |
| M.makeObjCIvarRef( |
| M.makeLvalueToRvalue( |
| M.makeDeclRefExpr(selfVar), |
| selfVar->getType()), |
| IVar); |
| |
| if (!Prop->getType()->isReferenceType()) |
| loadedIVar = M.makeLvalueToRvalue(loadedIVar, IVar->getType()); |
| |
| return M.makeReturn(loadedIVar); |
| } |
| |
| Stmt *BodyFarm::getBody(const ObjCMethodDecl *D) { |
| // We currently only know how to synthesize property accessors. |
| if (!D->isPropertyAccessor()) |
| return nullptr; |
| |
| D = D->getCanonicalDecl(); |
| |
| // We should not try to synthesize explicitly redefined accessors. |
| // We do not know for sure how they behave. |
| if (!D->isImplicit()) |
| return nullptr; |
| |
| Optional<Stmt *> &Val = Bodies[D]; |
| if (Val.hasValue()) |
| return Val.getValue(); |
| Val = nullptr; |
| |
| const ObjCPropertyDecl *Prop = D->findPropertyDecl(); |
| if (!Prop) |
| return nullptr; |
| |
| // For now, we only synthesize getters. |
| // Synthesizing setters would cause false negatives in the |
| // RetainCountChecker because the method body would bind the parameter |
| // to an instance variable, causing it to escape. This would prevent |
| // warning in the following common scenario: |
| // |
| // id foo = [[NSObject alloc] init]; |
| // self.foo = foo; // We should warn that foo leaks here. |
| // |
| if (D->param_size() != 0) |
| return nullptr; |
| |
| Val = createObjCPropertyGetter(C, Prop); |
| |
| return Val.getValue(); |
| } |
