1 //===--- AvoidGotoCheck.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 "AvoidGotoCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12
13 using namespace clang::ast_matchers;
14
15 namespace clang::tidy::cppcoreguidelines {
16
17 namespace {
AST_MATCHER(GotoStmt,isForwardJumping)18 AST_MATCHER(GotoStmt, isForwardJumping) {
19 return Node.getBeginLoc() < Node.getLabel()->getBeginLoc();
20 }
21 } // namespace
22
registerMatchers(MatchFinder * Finder)23 void AvoidGotoCheck::registerMatchers(MatchFinder *Finder) {
24 // TODO: This check does not recognize `IndirectGotoStmt` which is a
25 // GNU extension. These must be matched separately and an AST matcher
26 // is currently missing for them.
27
28 // Check if the 'goto' is used for control flow other than jumping
29 // out of a nested loop.
30 auto Loop = mapAnyOf(forStmt, cxxForRangeStmt, whileStmt, doStmt);
31 auto NestedLoop = Loop.with(hasAncestor(Loop));
32
33 Finder->addMatcher(gotoStmt(anyOf(unless(hasAncestor(NestedLoop)),
34 unless(isForwardJumping())))
35 .bind("goto"),
36 this);
37 }
38
check(const MatchFinder::MatchResult & Result)39 void AvoidGotoCheck::check(const MatchFinder::MatchResult &Result) {
40 const auto *Goto = Result.Nodes.getNodeAs<GotoStmt>("goto");
41
42 diag(Goto->getGotoLoc(), "avoid using 'goto' for flow control")
43 << Goto->getSourceRange();
44 diag(Goto->getLabel()->getBeginLoc(), "label defined here",
45 DiagnosticIDs::Note);
46 }
47 } // namespace clang::tidy::cppcoreguidelines
48