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 bool isCheckLikeMethod(llvm::SmallDenseSet<const CXXMethodDecl *> &CheckDecls, 20 const CXXMethodDecl &D) { 21 // All of the methods of interest are static, so avoid any lookup for 22 // non-static methods (the common case). 23 if (!D.isStatic()) 24 return false; 25 26 if (CheckDecls.empty()) { 27 // Attempt to initialize `CheckDecls` with the methods in class 28 // `CheckError`. 29 const CXXRecordDecl *ParentClass = D.getParent(); 30 if (ParentClass == nullptr || !ParentClass->getDeclName().isIdentifier() || 31 ParentClass->getName() != "CheckError") 32 return false; 33 34 // Check whether namespace is "logging". 35 const auto *N = 36 dyn_cast_or_null<NamespaceDecl>(ParentClass->getDeclContext()); 37 if (N == nullptr || !N->getDeclName().isIdentifier() || 38 N->getName() != "logging") 39 return false; 40 41 // Check whether "logging" is a top-level namespace. 42 if (N->getParent() == nullptr || !N->getParent()->isTranslationUnit()) 43 return false; 44 45 for (const CXXMethodDecl *M : ParentClass->methods()) 46 if (M->getDeclName().isIdentifier() && M->getName().endswith("Check")) 47 CheckDecls.insert(M); 48 } 49 50 return CheckDecls.contains(&D); 51 } 52 53 bool ChromiumCheckModel::transfer(const CFGElement *Element, Environment &Env) { 54 auto CS = Element->getAs<CFGStmt>(); 55 if (!CS) 56 return false; 57 auto Stmt = CS->getStmt(); 58 if (const auto *Call = dyn_cast<CallExpr>(Stmt)) { 59 if (const auto *M = dyn_cast<CXXMethodDecl>(Call->getDirectCallee())) { 60 if (isCheckLikeMethod(CheckDecls, *M)) { 61 // Mark this branch as unreachable. 62 Env.addToFlowCondition(Env.getBoolLiteralValue(false)); 63 return true; 64 } 65 } 66 } 67 return false; 68 } 69 70 } // namespace dataflow 71 } // namespace clang 72