1 //===--- SuspiciousSemicolonCheck.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 "SuspiciousSemicolonCheck.h"
10 #include "../utils/LexerUtils.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13
14 using namespace clang::ast_matchers;
15
16 namespace clang::tidy::bugprone {
17
registerMatchers(MatchFinder * Finder)18 void SuspiciousSemicolonCheck::registerMatchers(MatchFinder *Finder) {
19 Finder->addMatcher(
20 stmt(anyOf(ifStmt(hasThen(nullStmt().bind("semi")),
21 unless(hasElse(stmt())),
22 unless(isConstexpr())),
23 forStmt(hasBody(nullStmt().bind("semi"))),
24 cxxForRangeStmt(hasBody(nullStmt().bind("semi"))),
25 whileStmt(hasBody(nullStmt().bind("semi")))))
26 .bind("stmt"),
27 this);
28 }
29
check(const MatchFinder::MatchResult & Result)30 void SuspiciousSemicolonCheck::check(const MatchFinder::MatchResult &Result) {
31 if (Result.Context->getDiagnostics().hasUncompilableErrorOccurred())
32 return;
33
34 const auto *Semicolon = Result.Nodes.getNodeAs<NullStmt>("semi");
35 SourceLocation LocStart = Semicolon->getBeginLoc();
36
37 if (LocStart.isMacroID())
38 return;
39
40 ASTContext &Ctxt = *Result.Context;
41 auto Token = utils::lexer::getPreviousToken(LocStart, Ctxt.getSourceManager(),
42 Ctxt.getLangOpts());
43 auto &SM = *Result.SourceManager;
44 unsigned SemicolonLine = SM.getSpellingLineNumber(LocStart);
45
46 const auto *Statement = Result.Nodes.getNodeAs<Stmt>("stmt");
47 const bool IsIfStmt = isa<IfStmt>(Statement);
48
49 if (!IsIfStmt &&
50 SM.getSpellingLineNumber(Token.getLocation()) != SemicolonLine)
51 return;
52
53 SourceLocation LocEnd = Semicolon->getEndLoc();
54 FileID FID = SM.getFileID(LocEnd);
55 llvm::MemoryBufferRef Buffer = SM.getBufferOrFake(FID, LocEnd);
56 Lexer Lexer(SM.getLocForStartOfFile(FID), Ctxt.getLangOpts(),
57 Buffer.getBufferStart(), SM.getCharacterData(LocEnd) + 1,
58 Buffer.getBufferEnd());
59 if (Lexer.LexFromRawLexer(Token))
60 return;
61
62 unsigned BaseIndent = SM.getSpellingColumnNumber(Statement->getBeginLoc());
63 unsigned NewTokenIndent = SM.getSpellingColumnNumber(Token.getLocation());
64 unsigned NewTokenLine = SM.getSpellingLineNumber(Token.getLocation());
65
66 if (!IsIfStmt && NewTokenIndent <= BaseIndent &&
67 Token.getKind() != tok::l_brace && NewTokenLine != SemicolonLine)
68 return;
69
70 diag(LocStart, "potentially unintended semicolon")
71 << FixItHint::CreateRemoval(SourceRange(LocStart, LocEnd));
72 }
73
74 } // namespace clang::tidy::bugprone
75