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.
19bool 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>(Val: 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().ends_with(Suffix: "Check"))
47 CheckDecls.insert(V: M);
48 }
49
50 return CheckDecls.contains(V: &D);
51}
52
53bool 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>(Val: Stmt)) {
59 if (const auto *M = dyn_cast<CXXMethodDecl>(Val: Call->getDirectCallee())) {
60 if (isCheckLikeMethod(CheckDecls, D: *M)) {
61 // Mark this branch as unreachable.
62 Env.assume(Env.arena().makeLiteral(Value: false));
63 return true;
64 }
65 }
66 }
67 return false;
68}
69
70} // namespace dataflow
71} // namespace clang
72