[clang-tidy] Add a check to find unintended semicolons that changes the semantics.
Reviewers: hokein, alexfh
Differential Revision: http://reviews.llvm.org/D16535
llvm-svn: 260503
diff --git a/clang-tools-extra/clang-tidy/misc/SuspiciousSemicolonCheck.cpp b/clang-tools-extra/clang-tidy/misc/SuspiciousSemicolonCheck.cpp
new file mode 100644
index 0000000..5330f70
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/misc/SuspiciousSemicolonCheck.cpp
@@ -0,0 +1,74 @@
+//===--- 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 "../utils/LexerUtils.h"
+#include "SuspiciousSemicolonCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+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) {
+ const auto *Semicolon = Result.Nodes.getNodeAs<NullStmt>("semi");
+ SourceLocation LocStart = Semicolon->getLocStart();
+
+ if (LocStart.isMacroID())
+ return;
+
+ ASTContext &Ctxt = *Result.Context;
+ auto Token = lexer_utils::getPreviousNonCommentToken(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 misc
+} // namespace tidy
+} // namespace clang