Add new check in google module for Objective-C code to ensure global variables follow the naming convention of Google Objective-C Style Guide

Summary:
This is a new checker for objc files in clang-tidy.

The new check finds global variable declarations in Objective-C files that are not follow the pattern of variable names in Google's Objective-C Style Guide.

All the global variables should follow the pattern of "g[A-Z].*" (variables) or "k[A-Z].*" (constants). The check will suggest a variable name that follows the pattern
if it can be inferred from the original name.

Patch by Yan Zhang!

Reviewers: benhamilton, hokein, alexfh

Reviewed By: hokein

Subscribers: Eugene.Zelenko, mgorny

Differential Revision: https://reviews.llvm.org/D39391

llvm-svn: 317552

1 files changed, 39 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.h b/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.h
new file mode 100644
index 00000000000..ed0352bb871
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.h
@@ -0,0 +1,39 @@
+//===--- GlobalVariableDeclarationCheck.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_OBJC_GLOBAL_VARIABLE_DECLARATION_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_OBJC_GLOBAL_VARIABLE_DECLARATION_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace google {
+namespace objc {
+
+/// The check for Objective-C global variables and constants naming convention.
+/// The declaration should follow the patterns of 'k[A-Z].*' (constants) or
+/// 'g[A-Z].*' (variables).
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/google-objc-global-variable-declaration.html
+class GlobalVariableDeclarationCheck : public ClangTidyCheck {
+ public:
+  GlobalVariableDeclarationCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+}  // namespace objc
+}  // namespace google
+}  // namespace tidy
+}  // namespace clang
+
+#endif  // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_OBJC_GLOBAL_VARIABLE_DECLARATION_H