[clang-tidy] add new check to find out objc ivars which do not have prefix '_'

Summary:
For code of ivar declaration:

   int barWithoutPrefix;

The fix will be:

   int _barWithoutPrefix;

Reviewers: benhamilton, hokein, alexfh, aaron.ballman, ilya-biryukov

Reviewed By: alexfh

Subscribers: Eugene.Zelenko, xazax.hun, klimek, mgorny, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D45392

llvm-svn: 330492

2 files changed, 19 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
index 95a71f63986..c6b5265efdc 100644
--- a/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/IdentifierNamingCheck.cpp
@@ -109,6 +109,7 @@ namespace readability {
     m(TemplateParameter) \
     m(TypeAlias) \
     m(MacroDefinition) \
+    m(ObjcIvar) \
 
 enum StyleKind {
 #define ENUMERATE(v) SK_ ## v,
@@ -384,6 +385,9 @@ static StyleKind findStyleKind(
     const NamedDecl *D,
     const std::vector<llvm::Optional<IdentifierNamingCheck::NamingStyle>>
         &NamingStyles) {
+  if (isa<ObjCIvarDecl>(D) && NamingStyles[SK_ObjcIvar])
+    return SK_ObjcIvar;
+
   if (isa<TypedefDecl>(D) && NamingStyles[SK_Typedef])
     return SK_Typedef;
 
diff --git a/clang-tools-extra/test/clang-tidy/readability-identifier-naming-objc.m b/clang-tools-extra/test/clang-tidy/readability-identifier-naming-objc.m
new file mode 100644
index 00000000000..4b3be03fe92
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/readability-identifier-naming-objc.m
@@ -0,0 +1,15 @@
+// RUN: %check_clang_tidy %s readability-identifier-naming %t \
+// RUN: -config='{CheckOptions: \
+// RUN:  [{key: readability-identifier-naming.ObjcIvarPrefix, value: '_'}]}' \
+// RUN: --
+
+@interface Foo
+@end 
+
+@interface Foo () {
+    int _bar;
+    int barWithoutPrefix;
+    // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: invalid case style for objc ivar 'barWithoutPrefix' [readability-identifier-naming]
+    // CHECK-FIXES: int _barWithoutPrefix;
+}
+@end