Initial version of clang-tidy check to find and fix unused parameters.

Also see: llvm.org/PR24180.

llvm-svn: 242654

1 files changed, 43 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/misc/UnusedParametersCheck.cpp b/clang-tools-extra/clang-tidy/misc/UnusedParametersCheck.cpp
new file mode 100644
index 00000000000..170a274d70f
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/misc/UnusedParametersCheck.cpp
@@ -0,0 +1,43 @@
+//===--- UnusedParametersCheck.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 "UnusedParametersCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+
+void UnusedParametersCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      parmVarDecl(hasAncestor(functionDecl().bind("function"))).bind("x"),
+      this);
+}
+
+void UnusedParametersCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *Function = Result.Nodes.getNodeAs<FunctionDecl>("function");
+  if (!Function->doesThisDeclarationHaveABody())
+    return;
+  const auto *Param = Result.Nodes.getNodeAs<ParmVarDecl>("x");
+  if (Param->isUsed())
+    return;
+
+  auto MyDiag = diag(Param->getLocation(), "parameter '%0' is unused")
+                << Param->getName();
+
+  SourceRange RemovalRange(Param->getLocation(), Param->getLocEnd());
+  MyDiag << FixItHint::CreateReplacement(
+      RemovalRange, (Twine(" /*") + Param->getName() + "*/").str());
+}
+
+} // namespace tidy
+} // namespace clang
+