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 namespace clang { 18 19 std::pair<const Expr *, bool> 20 tryToFindPtrOrigin(const Expr *E, bool StopAtFirstRefCountedObj) { 21 while (E) { 22 if (auto *cast = dyn_cast<CastExpr>(E)) { 23 if (StopAtFirstRefCountedObj) { 24 if (auto *ConversionFunc = 25 dyn_cast_or_null<FunctionDecl>(cast->getConversionFunction())) { 26 if (isCtorOfRefCounted(ConversionFunc)) 27 return {E, true}; 28 } 29 } 30 // FIXME: This can give false "origin" that would lead to false negatives 31 // in checkers. See https://reviews.llvm.org/D37023 for reference. 32 E = cast->getSubExpr(); 33 continue; 34 } 35 if (auto *call = dyn_cast<CallExpr>(E)) { 36 if (auto *memberCall = dyn_cast<CXXMemberCallExpr>(call)) { 37 std::optional<bool> IsGetterOfRefCt = isGetterOfRefCounted(memberCall->getMethodDecl()); 38 if (IsGetterOfRefCt && *IsGetterOfRefCt) { 39 E = memberCall->getImplicitObjectArgument(); 40 if (StopAtFirstRefCountedObj) { 41 return {E, true}; 42 } 43 continue; 44 } 45 } 46 47 if (auto *operatorCall = dyn_cast<CXXOperatorCallExpr>(E)) { 48 if (operatorCall->getNumArgs() == 1) { 49 E = operatorCall->getArg(0); 50 continue; 51 } 52 } 53 54 if (auto *callee = call->getDirectCallee()) { 55 if (isCtorOfRefCounted(callee)) { 56 if (StopAtFirstRefCountedObj) 57 return {E, true}; 58 59 E = call->getArg(0); 60 continue; 61 } 62 63 if (isPtrConversion(callee)) { 64 E = call->getArg(0); 65 continue; 66 } 67 } 68 } 69 if (auto *unaryOp = dyn_cast<UnaryOperator>(E)) { 70 // FIXME: Currently accepts ANY unary operator. Is it OK? 71 E = unaryOp->getSubExpr(); 72 continue; 73 } 74 75 break; 76 } 77 // Some other expression. 78 return {E, false}; 79 } 80 81 bool isASafeCallArg(const Expr *E) { 82 assert(E); 83 if (auto *Ref = dyn_cast<DeclRefExpr>(E)) { 84 if (auto *D = dyn_cast_or_null<VarDecl>(Ref->getFoundDecl())) { 85 if (isa<ParmVarDecl>(D) || D->isLocalVarDecl()) 86 return true; 87 } 88 } 89 90 // TODO: checker for method calls on non-refcounted objects 91 return isa<CXXThisExpr>(E); 92 } 93 94 } // namespace clang 95