clang-tools-extra/clang-tidy/cppcoreguidelines/AvoidGotoCheck.cpp

   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 {
  18 AST_MATCHER(GotoStmt, isForwardJumping) {
  19   return Node.getBeginLoc() < Node.getLabel()->getBeginLoc();
  20 }
  21 } // namespace
  22
  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
  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