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
14namespace clang {
15namespace dataflow {
16
17/// Determines whether `D` is one of the methods used to implement Chromium's
18/// `CHECK` macros. Populates `CheckDecls`, if empty.
19static bool
20isCheckLikeMethod(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>(Val: 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(Suffix: "Check"))
48 CheckDecls.insert(V: M);
49 }
50
51 return CheckDecls.contains(V: &D);
52}
53
54bool 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>(Val: Stmt)) {
60 if (const auto *M =
61 dyn_cast_or_null<CXXMethodDecl>(Val: Call->getDirectCallee())) {
62 if (isCheckLikeMethod(CheckDecls, D: *M)) {
63 // Mark this branch as unreachable.
64 Env.assume(Env.arena().makeLiteral(Value: false));
65 return true;
66 }
67 }
68 }
69 return false;
70}
71
72} // namespace dataflow
73} // namespace clang
74