[clang-tidy] new google-default-arguments check

Summary:
To check the google style guide rule here:
https://google.github.io/styleguide/cppguide.html#Default_Arguments

Patch by Clement Courbet!

Reviewers: hokein

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D19534

llvm-svn: 268919

4 files changed, 74 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/google/CMakeLists.txt b/clang-tools-extra/clang-tidy/google/CMakeLists.txt
index 42274dcb717..efe3b3cde9c 100644
--- a/clang-tools-extra/clang-tidy/google/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/google/CMakeLists.txt
@@ -2,6 +2,7 @@ set(LLVM_LINK_COMPONENTS support)
 
 add_clang_library(clangTidyGoogleModule
   AvoidCStyleCastsCheck.cpp
+  DefaultArgumentsCheck.cpp
   ExplicitConstructorCheck.cpp
   ExplicitMakePairCheck.cpp
   GlobalNamesInHeadersCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/google/DefaultArgumentsCheck.cpp b/clang-tools-extra/clang-tidy/google/DefaultArgumentsCheck.cpp
new file mode 100644
index 00000000000..ccbd870a6ec
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/google/DefaultArgumentsCheck.cpp
@@ -0,0 +1,36 @@
+//===--- DefaultArgumentsCheck.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 "DefaultArgumentsCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace google {
+
+void DefaultArgumentsCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      cxxMethodDecl(anyOf(isOverride(), isVirtual()),
+                    hasAnyParameter(parmVarDecl(hasInitializer(expr()))))
+          .bind("Decl"),
+      this);
+}
+
+void DefaultArgumentsCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *MatchedDecl = Result.Nodes.getNodeAs<CXXMethodDecl>("Decl");
+  diag(MatchedDecl->getLocation(),
+       "default arguments on virtual or override methods are prohibited");
+}
+
+} // namespace google
+} // namespace tidy
+} // namespace clang
diff --git a/clang-tools-extra/clang-tidy/google/DefaultArgumentsCheck.h b/clang-tools-extra/clang-tidy/google/DefaultArgumentsCheck.h
new file mode 100644
index 00000000000..1457a093db6
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/google/DefaultArgumentsCheck.h
@@ -0,0 +1,34 @@
+//===--- DefaultArgumentsCheck.h - clang-tidy--------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_DEFAULT_ARGUMENTS_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_DEFAULT_ARGUMENTS_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace google {
+
+/// Checks that default parameters are not given for virtual methods.
+///
+/// See https://google.github.io/styleguide/cppguide.html#Default_Arguments
+class DefaultArgumentsCheck : public ClangTidyCheck {
+public:
+  DefaultArgumentsCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace google
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_DEFAULT_ARGUMENTS_H
diff --git a/clang-tools-extra/clang-tidy/google/GoogleTidyModule.cpp b/clang-tools-extra/clang-tidy/google/GoogleTidyModule.cpp
index 1281e15ff7b..49f879ccd9d 100644
--- a/clang-tools-extra/clang-tidy/google/GoogleTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/google/GoogleTidyModule.cpp
@@ -15,6 +15,7 @@
 #include "../readability/NamespaceCommentCheck.h"
 #include "../readability/RedundantSmartptrGetCheck.h"
 #include "AvoidCStyleCastsCheck.h"
+#include "DefaultArgumentsCheck.h"
 #include "ExplicitConstructorCheck.h"
 #include "ExplicitMakePairCheck.h"
 #include "GlobalNamesInHeadersCheck.h"
@@ -42,6 +43,8 @@ public:
         "google-build-namespaces");
     CheckFactories.registerCheck<build::UsingNamespaceDirectiveCheck>(
         "google-build-using-namespace");
+    CheckFactories.registerCheck<DefaultArgumentsCheck>(
+        "google-default-arguments");
     CheckFactories.registerCheck<ExplicitConstructorCheck>(
         "google-explicit-constructor");
     CheckFactories.registerCheck<runtime::IntegerTypesCheck>(