1 files changed, 77 insertions, 0 deletions
diff --git a/clang-tools-extra/clang-tidy/bugprone/SuspiciousSemicolonCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/SuspiciousSemicolonCheck.cpp
new file mode 100644
index 00000000000..d7f51d0d8bc
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/SuspiciousSemicolonCheck.cpp
@@ -0,0 +1,77 @@
+//===--- SuspiciousSemicolonCheck.cpp - clang-tidy-------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SuspiciousSemicolonCheck.h"
+#include "../utils/LexerUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+void SuspiciousSemicolonCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      stmt(anyOf(ifStmt(hasThen(nullStmt().bind("semi")),
+                        unless(hasElse(stmt()))),
+                 forStmt(hasBody(nullStmt().bind("semi"))),
+                 cxxForRangeStmt(hasBody(nullStmt().bind("semi"))),
+                 whileStmt(hasBody(nullStmt().bind("semi")))))
+          .bind("stmt"),
+      this);
+}
+
+void SuspiciousSemicolonCheck::check(const MatchFinder::MatchResult &Result) {
+  if (Result.Context->getDiagnostics().hasUncompilableErrorOccurred())
+    return;
+
+  const auto *Semicolon = Result.Nodes.getNodeAs<NullStmt>("semi");
+  SourceLocation LocStart = Semicolon->getLocStart();
+
+  if (LocStart.isMacroID())
+    return;
+
+  ASTContext &Ctxt = *Result.Context;
+  auto Token = utils::lexer::getPreviousToken(Ctxt, LocStart);
+  auto &SM = *Result.SourceManager;
+  unsigned SemicolonLine = SM.getSpellingLineNumber(LocStart);
+
+  const auto *Statement = Result.Nodes.getNodeAs<Stmt>("stmt");
+  const bool IsIfStmt = isa<IfStmt>(Statement);
+
+  if (!IsIfStmt &&
+      SM.getSpellingLineNumber(Token.getLocation()) != SemicolonLine)
+    return;
+
+  SourceLocation LocEnd = Semicolon->getLocEnd();
+  FileID FID = SM.getFileID(LocEnd);
+  llvm::MemoryBuffer *Buffer = SM.getBuffer(FID, LocEnd);
+  Lexer Lexer(SM.getLocForStartOfFile(FID), Ctxt.getLangOpts(),
+              Buffer->getBufferStart(), SM.getCharacterData(LocEnd) + 1,
+              Buffer->getBufferEnd());
+  if (Lexer.LexFromRawLexer(Token))
+    return;
+
+  unsigned BaseIndent = SM.getSpellingColumnNumber(Statement->getLocStart());
+  unsigned NewTokenIndent = SM.getSpellingColumnNumber(Token.getLocation());
+  unsigned NewTokenLine = SM.getSpellingLineNumber(Token.getLocation());
+
+  if (!IsIfStmt && NewTokenIndent <= BaseIndent &&
+      Token.getKind() != tok::l_brace && NewTokenLine != SemicolonLine)
+    return;
+
+  diag(LocStart, "potentially unintended semicolon")
+      << FixItHint::CreateRemoval(SourceRange(LocStart, LocEnd));
+}
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang