1 //=======- ASTUtils.cpp ------------------------------------------*- C++ -*-==// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "ASTUtils.h" 10 #include "PtrTypesSemantics.h" 11 #include "clang/AST/CXXInheritance.h" 12 #include "clang/AST/Decl.h" 13 #include "clang/AST/DeclCXX.h" 14 #include "clang/AST/ExprCXX.h" 15 #include <optional> 16 17 using llvm::Optional; 18 namespace clang { 19 20 std::pair<const Expr *, bool> 21 tryToFindPtrOrigin(const Expr *E, bool StopAtFirstRefCountedObj) { 22 while (E) { 23 if (auto *cast = dyn_cast<CastExpr>(E)) { 24 if (StopAtFirstRefCountedObj) { 25 if (auto *ConversionFunc = 26 dyn_cast_or_null<FunctionDecl>(cast->getConversionFunction())) { 27 if (isCtorOfRefCounted(ConversionFunc)) 28 return {E, true}; 29 } 30 } 31 // FIXME: This can give false "origin" that would lead to false negatives 32 // in checkers. See https://reviews.llvm.org/D37023 for reference. 33 E = cast->getSubExpr(); 34 continue; 35 } 36 if (auto *call = dyn_cast<CallExpr>(E)) { 37 if (auto *memberCall = dyn_cast<CXXMemberCallExpr>(call)) { 38 std::optional<bool> IsGetterOfRefCt = isGetterOfRefCounted(memberCall->getMethodDecl()); 39 if (IsGetterOfRefCt && *IsGetterOfRefCt) { 40 E = memberCall->getImplicitObjectArgument(); 41 if (StopAtFirstRefCountedObj) { 42 return {E, true}; 43 } 44 continue; 45 } 46 } 47 48 if (auto *operatorCall = dyn_cast<CXXOperatorCallExpr>(E)) { 49 if (operatorCall->getNumArgs() == 1) { 50 E = operatorCall->getArg(0); 51 continue; 52 } 53 } 54 55 if (auto *callee = call->getDirectCallee()) { 56 if (isCtorOfRefCounted(callee)) { 57 if (StopAtFirstRefCountedObj) 58 return {E, true}; 59 60 E = call->getArg(0); 61 continue; 62 } 63 64 if (isPtrConversion(callee)) { 65 E = call->getArg(0); 66 continue; 67 } 68 } 69 } 70 if (auto *unaryOp = dyn_cast<UnaryOperator>(E)) { 71 // FIXME: Currently accepts ANY unary operator. Is it OK? 72 E = unaryOp->getSubExpr(); 73 continue; 74 } 75 76 break; 77 } 78 // Some other expression. 79 return {E, false}; 80 } 81 82 bool isASafeCallArg(const Expr *E) { 83 assert(E); 84 if (auto *Ref = dyn_cast<DeclRefExpr>(E)) { 85 if (auto *D = dyn_cast_or_null<VarDecl>(Ref->getFoundDecl())) { 86 if (isa<ParmVarDecl>(D) || D->isLocalVarDecl()) 87 return true; 88 } 89 } 90 91 // TODO: checker for method calls on non-refcounted objects 92 return isa<CXXThisExpr>(E); 93 } 94 95 } // namespace clang 96