140 lines · cpp
1//===----------------------------------------------------------------------===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "MisleadingIndentationCheck.h"10#include "../utils/LexerUtils.h"11#include "clang/AST/ASTContext.h"12#include "clang/ASTMatchers/ASTMatchFinder.h"13 14using namespace clang::ast_matchers;15 16namespace clang::tidy::readability {17 18static const IfStmt *getPrecedingIf(const SourceManager &SM,19 ASTContext *Context, const IfStmt *If) {20 auto Parents = Context->getParents(*If);21 if (Parents.size() != 1)22 return nullptr;23 if (const auto *PrecedingIf = Parents[0].get<IfStmt>()) {24 const SourceLocation PreviousElseLoc = PrecedingIf->getElseLoc();25 if (SM.getExpansionLineNumber(PreviousElseLoc) ==26 SM.getExpansionLineNumber(If->getIfLoc()))27 return PrecedingIf;28 }29 return nullptr;30}31 32void MisleadingIndentationCheck::danglingElseCheck(const SourceManager &SM,33 ASTContext *Context,34 const IfStmt *If) {35 SourceLocation IfLoc = If->getIfLoc();36 const SourceLocation ElseLoc = If->getElseLoc();37 38 if (IfLoc.isMacroID() || ElseLoc.isMacroID())39 return;40 41 if (SM.getExpansionLineNumber(If->getThen()->getEndLoc()) ==42 SM.getExpansionLineNumber(ElseLoc))43 return;44 45 // Find location of first 'if' in a 'if else if' chain.46 for (const auto *PrecedingIf = getPrecedingIf(SM, Context, If); PrecedingIf;47 PrecedingIf = getPrecedingIf(SM, Context, PrecedingIf))48 IfLoc = PrecedingIf->getIfLoc();49 50 if (SM.getExpansionColumnNumber(IfLoc) !=51 SM.getExpansionColumnNumber(ElseLoc))52 diag(ElseLoc, "different indentation for 'if' and corresponding 'else'");53}54 55static bool isAtStartOfLineIncludingEmptyMacro(SourceLocation NextLoc,56 const SourceManager &SM,57 const LangOptions &LangOpts) {58 const SourceLocation BeforeLoc =59 utils::lexer::getPreviousTokenAndStart(NextLoc, SM, LangOpts).second;60 if (BeforeLoc.isInvalid())61 return false;62 return SM.getExpansionLineNumber(BeforeLoc) !=63 SM.getExpansionLineNumber(NextLoc);64}65 66void MisleadingIndentationCheck::missingBracesCheck(67 const SourceManager &SM, const CompoundStmt *CStmt,68 const LangOptions &LangOpts) {69 const static StringRef StmtNames[] = {"if", "for", "while"};70 for (unsigned int I = 0; I < CStmt->size() - 1; I++) {71 const Stmt *CurrentStmt = CStmt->body_begin()[I];72 const Stmt *Inner = nullptr;73 int StmtKind = 0;74 75 if (const auto *CurrentIf = dyn_cast<IfStmt>(CurrentStmt)) {76 StmtKind = 0;77 Inner =78 CurrentIf->getElse() ? CurrentIf->getElse() : CurrentIf->getThen();79 } else if (const auto *CurrentFor = dyn_cast<ForStmt>(CurrentStmt)) {80 StmtKind = 1;81 Inner = CurrentFor->getBody();82 } else if (const auto *CurrentWhile = dyn_cast<WhileStmt>(CurrentStmt)) {83 StmtKind = 2;84 Inner = CurrentWhile->getBody();85 } else {86 continue;87 }88 89 if (isa<CompoundStmt>(Inner))90 continue;91 92 const SourceLocation InnerLoc = Inner->getBeginLoc();93 const SourceLocation OuterLoc = CurrentStmt->getBeginLoc();94 95 if (InnerLoc.isInvalid() || InnerLoc.isMacroID() || OuterLoc.isInvalid() ||96 OuterLoc.isMacroID())97 continue;98 99 if (SM.getExpansionLineNumber(InnerLoc) ==100 SM.getExpansionLineNumber(OuterLoc))101 continue;102 103 const Stmt *NextStmt = CStmt->body_begin()[I + 1];104 const SourceLocation NextLoc = NextStmt->getBeginLoc();105 106 if (NextLoc.isInvalid() || NextLoc.isMacroID())107 continue;108 if (!isAtStartOfLineIncludingEmptyMacro(NextLoc, SM, LangOpts))109 continue;110 111 if (SM.getExpansionColumnNumber(InnerLoc) ==112 SM.getExpansionColumnNumber(NextLoc)) {113 diag(NextLoc, "misleading indentation: statement is indented too deeply");114 diag(OuterLoc, "did you mean this line to be inside this '%0'",115 DiagnosticIDs::Note)116 << StmtNames[StmtKind];117 }118 }119}120 121void MisleadingIndentationCheck::registerMatchers(MatchFinder *Finder) {122 Finder->addMatcher(123 ifStmt(unless(hasThen(nullStmt())), hasElse(stmt())).bind("if"), this);124 Finder->addMatcher(125 compoundStmt(has(stmt(anyOf(ifStmt(), forStmt(), whileStmt()))))126 .bind("compound"),127 this);128}129 130void MisleadingIndentationCheck::check(const MatchFinder::MatchResult &Result) {131 if (const auto *If = Result.Nodes.getNodeAs<IfStmt>("if"))132 danglingElseCheck(*Result.SourceManager, Result.Context, If);133 134 if (const auto *CStmt = Result.Nodes.getNodeAs<CompoundStmt>("compound"))135 missingBracesCheck(*Result.SourceManager, CStmt,136 Result.Context->getLangOpts());137}138 139} // namespace clang::tidy::readability140