clang-tools-extra/clang-tidy/readability/AvoidReturnWithVoidValueCheck.cpp

   1 //===--- AvoidReturnWithVoidValueCheck.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 "AvoidReturnWithVoidValueCheck.h"
  10 #include "../utils/BracesAroundStatement.h"
  11 #include "../utils/LexerUtils.h"
  12
  13 using namespace clang::ast_matchers;
  14
  15 namespace clang::tidy::readability {
  16
  17 static constexpr char IgnoreMacrosName[] = "IgnoreMacros";
  18 static const bool IgnoreMacrosDefault = true;
  19
  20 static constexpr char StrictModeName[] = "StrictMode";
  21 static const bool StrictModeDefault = true;
  22
  23 AvoidReturnWithVoidValueCheck::AvoidReturnWithVoidValueCheck(
  24     StringRef Name, ClangTidyContext *Context)
  25     : ClangTidyCheck(Name, Context),
  26       IgnoreMacros(
  27           Options.getLocalOrGlobal(IgnoreMacrosName, IgnoreMacrosDefault)),
  28       StrictMode(Options.getLocalOrGlobal(StrictModeName, StrictModeDefault)) {}
  29
  30 void AvoidReturnWithVoidValueCheck::registerMatchers(MatchFinder *Finder) {
  31   Finder->addMatcher(
  32       returnStmt(
  33           hasReturnValue(allOf(hasType(voidType()), unless(initListExpr()))),
  34           optionally(hasParent(
  35               compoundStmt(
  36                   optionally(hasParent(functionDecl().bind("function_parent"))))
  37                   .bind("compound_parent"))))
  38           .bind("void_return"),
  39       this);
  40 }
  41
  42 void AvoidReturnWithVoidValueCheck::check(
  43     const MatchFinder::MatchResult &Result) {
  44   const auto *VoidReturn = Result.Nodes.getNodeAs<ReturnStmt>("void_return");
  45   if (IgnoreMacros && VoidReturn->getBeginLoc().isMacroID())
  46     return;
  47   const auto *SurroundingBlock =
  48       Result.Nodes.getNodeAs<CompoundStmt>("compound_parent");
  49   if (!StrictMode && !SurroundingBlock)
  50     return;
  51   DiagnosticBuilder Diag = diag(VoidReturn->getBeginLoc(),
  52                                 "return statement within a void function "
  53                                 "should not have a specified return value");
  54   const SourceLocation SemicolonPos = utils::lexer::findNextTerminator(
  55       VoidReturn->getEndLoc(), *Result.SourceManager, getLangOpts());
  56   if (SemicolonPos.isInvalid())
  57     return;
  58   if (!SurroundingBlock) {
  59     const auto BraceInsertionHints = utils::getBraceInsertionsHints(
  60         VoidReturn, getLangOpts(), *Result.SourceManager,
  61         VoidReturn->getBeginLoc());
  62     if (BraceInsertionHints)
  63       Diag << BraceInsertionHints.openingBraceFixIt()
  64            << BraceInsertionHints.closingBraceFixIt();
  65   }
  66   Diag << FixItHint::CreateRemoval(VoidReturn->getReturnLoc());
  67   const auto *FunctionParent =
  68       Result.Nodes.getNodeAs<FunctionDecl>("function_parent");
  69   if (!FunctionParent ||
  70       (SurroundingBlock && SurroundingBlock->body_back() != VoidReturn))
  71     // If this is not the last statement in a function body, we add a `return`.
  72     Diag << FixItHint::CreateInsertion(SemicolonPos.getLocWithOffset(1),
  73                                        " return;", true);
  74 }
  75
  76 void AvoidReturnWithVoidValueCheck::storeOptions(
  77     ClangTidyOptions::OptionMap &Opts) {
  78   Options.store(Opts, IgnoreMacrosName, IgnoreMacros);
  79   Options.store(Opts, StrictModeName, StrictMode);
  80 }
  81
  82 } // namespace clang::tidy::readability