From b1e78df0fa1cf9a0e85f4cd11702cfad28581723 Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dimitry@andric.com>
Date: Thu, 5 Feb 2015 07:40:48 +0000
Subject: [PATCH] Fix unused private field warning in stdexcept after r207695.

Add a new _LIBCPP_UNUSED define in __config, which can be used to
indicate explicitly unused items, and apply it to the __imp__ field of
__libcpp_refstring.

Somebody who knows about Microsoft C++ and IBM C++ should fill in the
unused attribute syntax appropriate for those compilers, if there is
any.

Differential Revision: http://reviews.llvm.org/D6836

llvm-svn: 228281
---
 libcxx/include/__config  | 6 ++++++
 libcxx/include/stdexcept | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/libcxx/include/__config b/libcxx/include/__config
index 00ade4ef2914..b109ad773ed2 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -258,6 +258,8 @@ typedef __char32_t char32_t;
 #  define _LIBCPP_NORETURN __attribute__ ((noreturn))
 #endif
 
+#define _LIBCPP_UNUSED __attribute__((__unused__))
+
 #if !(__has_feature(cxx_defaulted_functions))
 #define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
 #endif  // !(__has_feature(cxx_defaulted_functions))
@@ -380,6 +382,8 @@ namespace std {
 
 #define _LIBCPP_NORETURN __attribute__((noreturn))
 
+#define _LIBCPP_UNUSED __attribute__((__unused__))
+
 #if _GNUC_VER >= 407
 #define _LIBCPP_UNDERLYING_TYPE(T) __underlying_type(T)
 #define _LIBCPP_IS_LITERAL(T) __is_literal_type(T)
@@ -477,6 +481,7 @@ using namespace _LIBCPP_NAMESPACE __attribute__((__strong__));
 #define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
 #define __alignof__ __alignof
 #define _LIBCPP_NORETURN __declspec(noreturn)
+#define _LIBCPP_UNUSED
 #define _ALIGNAS(x) __declspec(align(x))
 #define _LIBCPP_HAS_NO_VARIADICS
 
@@ -500,6 +505,7 @@ namespace std {
 #define _ALIGNAS_TYPE(x) __attribute__((__aligned__(__alignof(x))))
 #define _ATTRIBUTE(x) __attribute__((x))
 #define _LIBCPP_NORETURN __attribute__((noreturn))
+#define _LIBCPP_UNUSED
 
 #define _NOEXCEPT throw()
 #define _NOEXCEPT_(x)
diff --git a/libcxx/include/stdexcept b/libcxx/include/stdexcept
index 5fc912a644be..f251806fba62 100644
--- a/libcxx/include/stdexcept
+++ b/libcxx/include/stdexcept
@@ -53,7 +53,7 @@ public:
 #ifndef _LIBCPP___REFSTRING
 _LIBCPP_BEGIN_NAMESPACE_STD
 class _LIBCPP_HIDDEN __libcpp_refstring {
-    const char *__imp_;
+    const char *__imp_ _LIBCPP_UNUSED;
 };
 _LIBCPP_END_NAMESPACE_STD
 #endif