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 {
16 namespace tidy {
17 namespace cppcoreguidelines {
18
19 namespace {
AST_MATCHER(GotoStmt,isForwardJumping)20 AST_MATCHER(GotoStmt, isForwardJumping) {
21 return Node.getBeginLoc() < Node.getLabel()->getBeginLoc();
22 }
23 } // namespace
24
registerMatchers(MatchFinder * Finder)25 void AvoidGotoCheck::registerMatchers(MatchFinder *Finder) {
26 // TODO: This check does not recognize `IndirectGotoStmt` which is a
27 // GNU extension. These must be matched separately and an AST matcher
28 // is currently missing for them.
29
30 // Check if the 'goto' is used for control flow other than jumping
31 // out of a nested loop.
32 auto Loop = mapAnyOf(forStmt, cxxForRangeStmt, whileStmt, doStmt);
33 auto NestedLoop = Loop.with(hasAncestor(Loop));
34
35 Finder->addMatcher(gotoStmt(anyOf(unless(hasAncestor(NestedLoop)),
36 unless(isForwardJumping())))
37 .bind("goto"),
38 this);
39 }
40
check(const MatchFinder::MatchResult & Result)41 void AvoidGotoCheck::check(const MatchFinder::MatchResult &Result) {
42 const auto *Goto = Result.Nodes.getNodeAs<GotoStmt>("goto");
43
44 diag(Goto->getGotoLoc(), "avoid using 'goto' for flow control")
45 << Goto->getSourceRange();
46 diag(Goto->getLabel()->getBeginLoc(), "label defined here",
47 DiagnosticIDs::Note);
48 }
49 } // namespace cppcoreguidelines
50 } // namespace tidy
51 } // namespace clang
52