1 //===-- ChromiumCheckModel.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 "clang/Analysis/FlowSensitive/Models/ChromiumCheckModel.h" 10 #include "clang/AST/Decl.h" 11 #include "clang/AST/DeclCXX.h" 12 #include "llvm/ADT/DenseSet.h" 13 14 namespace clang { 15 namespace dataflow { 16 17 /// Determines whether `D` is one of the methods used to implement Chromium's 18 /// `CHECK` macros. Populates `CheckDecls`, if empty. 19 static bool 20 isCheckLikeMethod(llvm::SmallDenseSet<const CXXMethodDecl *> &CheckDecls, 21 const CXXMethodDecl &D) { 22 // All of the methods of interest are static, so avoid any lookup for 23 // non-static methods (the common case). 24 if (!D.isStatic()) 25 return false; 26 27 if (CheckDecls.empty()) { 28 // Attempt to initialize `CheckDecls` with the methods in class 29 // `CheckError`. 30 const CXXRecordDecl *ParentClass = D.getParent(); 31 if (ParentClass == nullptr || !ParentClass->getDeclName().isIdentifier() || 32 ParentClass->getName() != "CheckError") 33 return false; 34 35 // Check whether namespace is "logging". 36 const auto *N = 37 dyn_cast_or_null<NamespaceDecl>(ParentClass->getDeclContext()); 38 if (N == nullptr || !N->getDeclName().isIdentifier() || 39 N->getName() != "logging") 40 return false; 41 42 // Check whether "logging" is a top-level namespace. 43 if (N->getParent() == nullptr || !N->getParent()->isTranslationUnit()) 44 return false; 45 46 for (const CXXMethodDecl *M : ParentClass->methods()) 47 if (M->getDeclName().isIdentifier() && M->getName().ends_with("Check")) 48 CheckDecls.insert(M); 49 } 50 51 return CheckDecls.contains(&D); 52 } 53 54 bool ChromiumCheckModel::transfer(const CFGElement &Element, Environment &Env) { 55 auto CS = Element.getAs<CFGStmt>(); 56 if (!CS) 57 return false; 58 auto Stmt = CS->getStmt(); 59 if (const auto *Call = dyn_cast<CallExpr>(Stmt)) { 60 if (const auto *M = 61 dyn_cast_or_null<CXXMethodDecl>(Call->getDirectCallee())) { 62 if (isCheckLikeMethod(CheckDecls, *M)) { 63 // Mark this branch as unreachable. 64 Env.assume(Env.arena().makeLiteral(false)); 65 return true; 66 } 67 } 68 } 69 return false; 70 } 71 72 } // namespace dataflow 73 } // namespace clang 74