1 //===--- RedundantControlFlowCheck.cpp - clang-tidy------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "RedundantControlFlowCheck.h" 11 #include "clang/AST/ASTContext.h" 12 #include "clang/ASTMatchers/ASTMatchFinder.h" 13 #include "clang/Lex/Lexer.h" 14 15 using namespace clang::ast_matchers; 16 17 namespace clang { 18 namespace tidy { 19 namespace readability { 20 21 namespace { 22 23 const char *const RedundantReturnDiag = "redundant return statement at the end " 24 "of a function with a void return type"; 25 const char *const RedundantContinueDiag = "redundant continue statement at the " 26 "end of loop statement"; 27 28 bool isLocationInMacroExpansion(const SourceManager &SM, SourceLocation Loc) { 29 return SM.isMacroBodyExpansion(Loc) || SM.isMacroArgExpansion(Loc); 30 } 31 32 } // namespace 33 34 void RedundantControlFlowCheck::registerMatchers(MatchFinder *Finder) { 35 Finder->addMatcher( 36 functionDecl( 37 isDefinition(), returns(voidType()), 38 has(compoundStmt(hasAnySubstatement(returnStmt(unless(has(expr()))))) 39 .bind("return"))), 40 this); 41 auto CompoundContinue = 42 has(compoundStmt(hasAnySubstatement(continueStmt())).bind("continue")); 43 Finder->addMatcher( 44 stmt(anyOf(forStmt(), cxxForRangeStmt(), whileStmt(), doStmt()), 45 CompoundContinue), 46 this); 47 } 48 49 void RedundantControlFlowCheck::check(const MatchFinder::MatchResult &Result) { 50 if (const auto *Return = Result.Nodes.getNodeAs<CompoundStmt>("return")) 51 checkRedundantReturn(Result, Return); 52 else if (const auto *Continue = 53 Result.Nodes.getNodeAs<CompoundStmt>("continue")) 54 checkRedundantContinue(Result, Continue); 55 } 56 57 void RedundantControlFlowCheck::checkRedundantReturn( 58 const MatchFinder::MatchResult &Result, const CompoundStmt *Block) { 59 CompoundStmt::const_reverse_body_iterator last = Block->body_rbegin(); 60 if (const auto *Return = dyn_cast<ReturnStmt>(*last)) 61 issueDiagnostic(Result, Block, Return->getSourceRange(), 62 RedundantReturnDiag); 63 } 64 65 void RedundantControlFlowCheck::checkRedundantContinue( 66 const MatchFinder::MatchResult &Result, const CompoundStmt *Block) { 67 CompoundStmt::const_reverse_body_iterator last = Block->body_rbegin(); 68 if (const auto *Continue = dyn_cast<ContinueStmt>(*last)) 69 issueDiagnostic(Result, Block, Continue->getSourceRange(), 70 RedundantContinueDiag); 71 } 72 73 void RedundantControlFlowCheck::issueDiagnostic( 74 const MatchFinder::MatchResult &Result, const CompoundStmt *const Block, 75 const SourceRange &StmtRange, const char *const Diag) { 76 SourceManager &SM = *Result.SourceManager; 77 if (isLocationInMacroExpansion(SM, StmtRange.getBegin())) 78 return; 79 80 CompoundStmt::const_reverse_body_iterator Previous = ++Block->body_rbegin(); 81 SourceLocation Start; 82 if (Previous != Block->body_rend()) 83 Start = Lexer::findLocationAfterToken( 84 dyn_cast<Stmt>(*Previous)->getLocEnd(), tok::semi, SM, getLangOpts(), 85 /*SkipTrailingWhitespaceAndNewLine=*/true); 86 if (!Start.isValid()) 87 Start = StmtRange.getBegin(); 88 auto RemovedRange = CharSourceRange::getCharRange( 89 Start, Lexer::findLocationAfterToken( 90 StmtRange.getEnd(), tok::semi, SM, getLangOpts(), 91 /*SkipTrailingWhitespaceAndNewLine=*/true)); 92 93 diag(StmtRange.getBegin(), Diag) << FixItHint::CreateRemoval(RemovedRange); 94 } 95 96 } // namespace readability 97 } // namespace tidy 98 } // namespace clang 99