clang-tools  8.0.0
SuspiciousSemicolonCheck.cpp
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1 //===--- SuspiciousSemicolonCheck.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 
11 #include "../utils/LexerUtils.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/ASTMatchers/ASTMatchFinder.h"
14 
15 using namespace clang::ast_matchers;
16 
17 namespace clang {
18 namespace tidy {
19 namespace bugprone {
20 
21 void SuspiciousSemicolonCheck::registerMatchers(MatchFinder *Finder) {
22  Finder->addMatcher(
23  stmt(anyOf(ifStmt(hasThen(nullStmt().bind("semi")),
24  unless(hasElse(stmt()))),
25  forStmt(hasBody(nullStmt().bind("semi"))),
26  cxxForRangeStmt(hasBody(nullStmt().bind("semi"))),
27  whileStmt(hasBody(nullStmt().bind("semi")))))
28  .bind("stmt"),
29  this);
30 }
31 
32 void SuspiciousSemicolonCheck::check(const MatchFinder::MatchResult &Result) {
33  if (Result.Context->getDiagnostics().hasUncompilableErrorOccurred())
34  return;
35 
36  const auto *Semicolon = Result.Nodes.getNodeAs<NullStmt>("semi");
37  SourceLocation LocStart = Semicolon->getBeginLoc();
38 
39  if (LocStart.isMacroID())
40  return;
41 
42  ASTContext &Ctxt = *Result.Context;
43  auto Token = utils::lexer::getPreviousToken(LocStart, Ctxt.getSourceManager(),
44  Ctxt.getLangOpts());
45  auto &SM = *Result.SourceManager;
46  unsigned SemicolonLine = SM.getSpellingLineNumber(LocStart);
47 
48  const auto *Statement = Result.Nodes.getNodeAs<Stmt>("stmt");
49  const bool IsIfStmt = isa<IfStmt>(Statement);
50 
51  if (!IsIfStmt &&
52  SM.getSpellingLineNumber(Token.getLocation()) != SemicolonLine)
53  return;
54 
55  SourceLocation LocEnd = Semicolon->getEndLoc();
56  FileID FID = SM.getFileID(LocEnd);
57  llvm::MemoryBuffer *Buffer = SM.getBuffer(FID, LocEnd);
58  Lexer Lexer(SM.getLocForStartOfFile(FID), Ctxt.getLangOpts(),
59  Buffer->getBufferStart(), SM.getCharacterData(LocEnd) + 1,
60  Buffer->getBufferEnd());
61  if (Lexer.LexFromRawLexer(Token))
62  return;
63 
64  unsigned BaseIndent = SM.getSpellingColumnNumber(Statement->getBeginLoc());
65  unsigned NewTokenIndent = SM.getSpellingColumnNumber(Token.getLocation());
66  unsigned NewTokenLine = SM.getSpellingLineNumber(Token.getLocation());
67 
68  if (!IsIfStmt && NewTokenIndent <= BaseIndent &&
69  Token.getKind() != tok::l_brace && NewTokenLine != SemicolonLine)
70  return;
71 
72  diag(LocStart, "potentially unintended semicolon")
73  << FixItHint::CreateRemoval(SourceRange(LocStart, LocEnd));
74 }
75 
76 } // namespace bugprone
77 } // namespace tidy
78 } // namespace clang
Token getPreviousToken(SourceLocation Location, const SourceManager &SM, const LangOptions &LangOpts, bool SkipComments)
Returns previous token or tok::unknown if not found.
Definition: LexerUtils.cpp:17
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//