1 //===--- LimitedRandomnessCheck.cpp - clang-tidy---------------------------===//
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 "LimitedRandomnessCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 
13 using namespace clang::ast_matchers;
14 
15 namespace clang {
16 namespace tidy {
17 namespace cert {
18 
registerMatchers(MatchFinder * Finder)19 void LimitedRandomnessCheck::registerMatchers(MatchFinder *Finder) {
20   Finder->addMatcher(callExpr(callee(functionDecl(namedDecl(hasName("::rand")),
21                                                   parameterCountIs(0))))
22                          .bind("randomGenerator"),
23                      this);
24 }
25 
check(const MatchFinder::MatchResult & Result)26 void LimitedRandomnessCheck::check(const MatchFinder::MatchResult &Result) {
27   std::string Msg = "";
28   if (getLangOpts().CPlusPlus)
29     Msg = "; use C++11 random library instead";
30 
31   const auto *MatchedDecl = Result.Nodes.getNodeAs<CallExpr>("randomGenerator");
32   diag(MatchedDecl->getBeginLoc(), "rand() has limited randomness" + Msg);
33 }
34 
35 } // namespace cert
36 } // namespace tidy
37 } // namespace clang
38