import of libc++ 6.0.0

3 files changed, 157 insertions, 6 deletions

diff --git a/lib/libcxx/src/include/atomic_support.h b/lib/libcxx/src/include/atomic_support.h
index 8b719c5f221..ccd8d78d3d7 100644
--- a/lib/libcxx/src/include/atomic_support.h
+++ b/lib/libcxx/src/include/atomic_support.h
@@ -16,6 +16,7 @@
 #if defined(__clang__) && __has_builtin(__atomic_load_n)             \
                        && __has_builtin(__atomic_store_n)            \
                        && __has_builtin(__atomic_add_fetch)          \
+                       && __has_builtin(__atomic_exchange_n)         \
                        && __has_builtin(__atomic_compare_exchange_n) \
                        && defined(__ATOMIC_RELAXED)                  \
                        && defined(__ATOMIC_CONSUME)                  \
@@ -29,7 +30,7 @@
 #endif
 
 #if !defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS)
-# if defined(_MSC_VER) && !defined(__clang__)
+# if defined(_LIBCPP_WARNING)
     _LIBCPP_WARNING("Building libc++ without __atomic builtins is unsupported")
 # else
 #   warning Building libc++ without __atomic builtins is unsupported
@@ -45,7 +46,7 @@ namespace {
 enum __libcpp_atomic_order {
     _AO_Relaxed = __ATOMIC_RELAXED,
     _AO_Consume = __ATOMIC_CONSUME,
-    _AO_Aquire  = __ATOMIC_ACQUIRE,
+    _AO_Acquire = __ATOMIC_ACQUIRE,
     _AO_Release = __ATOMIC_RELEASE,
     _AO_Acq_Rel = __ATOMIC_ACQ_REL,
     _AO_Seq     = __ATOMIC_SEQ_CST
@@ -84,6 +85,14 @@ _ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a,
 
 template <class _ValueType>
 inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_atomic_exchange(_ValueType* __target,
+                                    _ValueType __value, int __order = _AO_Seq)
+{
+    return __atomic_exchange_n(__target, __value, __order);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
 bool __libcpp_atomic_compare_exchange(_ValueType* __val,
     _ValueType* __expected, _ValueType __after,
     int __success_order = _AO_Seq,
@@ -137,6 +146,16 @@ _ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a,
 
 template <class _ValueType>
 inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_atomic_exchange(_ValueType* __target,
+                                    _ValueType __value, int __order = _AO_Seq)
+{
+    _ValueType old = *__target;
+    *__target = __value;
+    return old;
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
 bool __libcpp_atomic_compare_exchange(_ValueType* __val,
     _ValueType* __expected, _ValueType __after,
     int = 0, int = 0)
diff --git a/lib/libcxx/src/include/config_elast.h b/lib/libcxx/src/include/config_elast.h
index 9d6a76b0c00..4c4d853c2a6 100644
--- a/lib/libcxx/src/include/config_elast.h
+++ b/lib/libcxx/src/include/config_elast.h
@@ -10,7 +10,9 @@
 #ifndef _LIBCPP_CONFIG_ELAST
 #define _LIBCPP_CONFIG_ELAST
 
-#if defined(_WIN32)
+#include <__config>
+
+#if defined(_LIBCPP_MSVCRT)
 #include <stdlib.h>
 #else
 #include <errno.h>
@@ -20,14 +22,16 @@
 #define _LIBCPP_ELAST ELAST
 #elif defined(_NEWLIB_VERSION)
 #define _LIBCPP_ELAST __ELASTERROR
-#elif defined(__linux__)
+#elif defined(__Fuchsia__)
+// No _LIBCPP_ELAST needed on Fuchsia
+#elif defined(__linux__) || defined(_LIBCPP_HAS_MUSL_LIBC)
 #define _LIBCPP_ELAST 4095
 #elif defined(__APPLE__)
 // No _LIBCPP_ELAST needed on Apple
 #elif defined(__sun__)
 #define _LIBCPP_ELAST ESTALE
-#elif defined(_WIN32)
-#define _LIBCPP_ELAST _sys_nerr
+#elif defined(_LIBCPP_MSVCRT)
+#define _LIBCPP_ELAST (_sys_nerr - 1)
 #else
 // Warn here so that the person doing the libcxx port has an easier time:
 #warning ELAST for this platform not yet implemented
diff --git a/lib/libcxx/src/include/refstring.h b/lib/libcxx/src/include/refstring.h
new file mode 100644
index 00000000000..702f2b7388d
--- /dev/null
+++ b/lib/libcxx/src/include/refstring.h
@@ -0,0 +1,128 @@
+//===------------------------ __refstring ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_REFSTRING_H
+#define _LIBCPP_REFSTRING_H
+
+#include <__config>
+#include <stdexcept>
+#include <cstddef>
+#include <cstring>
+#ifdef __APPLE__
+#include <dlfcn.h>
+#include <mach-o/dyld.h>
+#endif
+#include "atomic_support.h"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace __refstring_imp { namespace {
+typedef int count_t;
+
+struct _Rep_base {
+    std::size_t len;
+    std::size_t cap;
+    count_t     count;
+};
+
+inline _Rep_base* rep_from_data(const char *data_) noexcept {
+    char *data = const_cast<char *>(data_);
+    return reinterpret_cast<_Rep_base *>(data - sizeof(_Rep_base));
+}
+
+inline char * data_from_rep(_Rep_base *rep) noexcept {
+    char *data = reinterpret_cast<char *>(rep);
+    return data + sizeof(*rep);
+}
+
+#if defined(__APPLE__)
+inline
+const char* compute_gcc_empty_string_storage() _NOEXCEPT
+{
+    void* handle = dlopen("/usr/lib/libstdc++.6.dylib", RTLD_NOLOAD);
+    if (handle == nullptr)
+        return nullptr;
+    void* sym = dlsym(handle, "_ZNSs4_Rep20_S_empty_rep_storageE");
+    if (sym == nullptr)
+        return nullptr;
+    return data_from_rep(reinterpret_cast<_Rep_base *>(sym));
+}
+
+inline
+const char*
+get_gcc_empty_string_storage() _NOEXCEPT
+{
+    static const char* p = compute_gcc_empty_string_storage();
+    return p;
+}
+#endif
+
+}} // namespace __refstring_imp
+
+using namespace __refstring_imp;
+
+inline
+__libcpp_refstring::__libcpp_refstring(const char* msg) {
+    std::size_t len = strlen(msg);
+    _Rep_base* rep = static_cast<_Rep_base *>(::operator new(sizeof(*rep) + len + 1));
+    rep->len = len;
+    rep->cap = len;
+    rep->count = 0;
+    char *data = data_from_rep(rep);
+    std::memcpy(data, msg, len + 1);
+    __imp_ = data;
+}
+
+inline
+__libcpp_refstring::__libcpp_refstring(const __libcpp_refstring &s) _NOEXCEPT
+    : __imp_(s.__imp_)
+{
+    if (__uses_refcount())
+        __libcpp_atomic_add(&rep_from_data(__imp_)->count, 1);
+}
+
+inline
+__libcpp_refstring& __libcpp_refstring::operator=(__libcpp_refstring const& s) _NOEXCEPT {
+    bool adjust_old_count = __uses_refcount();
+    struct _Rep_base *old_rep = rep_from_data(__imp_);
+    __imp_ = s.__imp_;
+    if (__uses_refcount())
+        __libcpp_atomic_add(&rep_from_data(__imp_)->count, 1);
+    if (adjust_old_count)
+    {
+        if (__libcpp_atomic_add(&old_rep->count, count_t(-1)) < 0)
+        {
+            ::operator delete(old_rep);
+        }
+    }
+    return *this;
+}
+
+inline
+__libcpp_refstring::~__libcpp_refstring() {
+    if (__uses_refcount()) {
+        _Rep_base* rep = rep_from_data(__imp_);
+        if (__libcpp_atomic_add(&rep->count, count_t(-1)) < 0) {
+            ::operator delete(rep);
+        }
+    }
+}
+
+inline
+bool __libcpp_refstring::__uses_refcount() const {
+#ifdef __APPLE__
+    return __imp_ != get_gcc_empty_string_storage();
+#else
+    return true;
+#endif
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif //_LIBCPP_REFSTRING_H