import of libc++ 6.0.0

1 files changed, 58 insertions, 25 deletions

diff --git a/lib/libcxx/src/system_error.cpp b/lib/libcxx/src/system_error.cpp
index 87f35ae37f3..72623ea6bc8 100644
--- a/lib/libcxx/src/system_error.cpp
+++ b/lib/libcxx/src/system_error.cpp
@@ -17,9 +17,9 @@
 #include "cstring"
 #include "cstdio"
 #include "cstdlib"
-#include "cassert"
 #include "string"
 #include "string.h"
+#include "__debug"
 
 #if defined(__ANDROID__)
 #include <android/api-level.h>
@@ -29,9 +29,11 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 // class error_category
 
+#if defined(_LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS)
 error_category::error_category() _NOEXCEPT
 {
 }
+#endif
 
 error_category::~error_category() _NOEXCEPT
 {
@@ -55,6 +57,7 @@ error_category::equivalent(const error_code& code, int condition) const _NOEXCEP
     return *this == code.category() && code.value() == condition;
 }
 
+#if !defined(_LIBCPP_HAS_NO_THREADS)
 namespace {
 
 //  GLIBC also uses 1024 as the maximum buffer size internally.
@@ -62,40 +65,69 @@ constexpr size_t strerror_buff_size = 1024;
 
 string do_strerror_r(int ev);
 
-#if defined(__linux__) && !defined(_LIBCPP_HAS_MUSL_LIBC)                      \
-    && (!defined(__ANDROID__) || __ANDROID_API__ >= 23)
-// GNU Extended version
+#if defined(_LIBCPP_MSVCRT_LIKE)
 string do_strerror_r(int ev) {
-    char buffer[strerror_buff_size];
-    char* ret = ::strerror_r(ev, buffer, strerror_buff_size);
-    return string(ret);
+  char buffer[strerror_buff_size];
+  if (::strerror_s(buffer, strerror_buff_size, ev) == 0)
+    return string(buffer);
+  std::snprintf(buffer, strerror_buff_size, "unknown error %d", ev);
+  return string(buffer);
 }
 #else
-// POSIX version
+
+// Only one of the two following functions will be used, depending on
+// the return type of strerror_r:
+
+// For the GNU variant, a char* return value:
+__attribute__((unused)) const char *
+handle_strerror_r_return(char *strerror_return, char *buffer) {
+  // GNU always returns a string pointer in its return value. The
+  // string might point to either the input buffer, or a static
+  // buffer, but we don't care which.
+  return strerror_return;
+}
+
+// For the POSIX variant: an int return value.
+__attribute__((unused)) const char *
+handle_strerror_r_return(int strerror_return, char *buffer) {
+  // The POSIX variant either:
+  // - fills in the provided buffer and returns 0
+  // - returns a positive error value, or
+  // - returns -1 and fills in errno with an error value.
+  if (strerror_return == 0)
+    return buffer;
+
+  // Only handle EINVAL. Other errors abort.
+  int new_errno = strerror_return == -1 ? errno : strerror_return;
+  if (new_errno == EINVAL)
+    return "";
+
+  _LIBCPP_ASSERT(new_errno == ERANGE, "unexpected error from ::strerror_r");
+  // FIXME maybe? 'strerror_buff_size' is likely to exceed the
+  // maximum error size so ERANGE shouldn't be returned.
+  std::abort();
+}
+
+// This function handles both GNU and POSIX variants, dispatching to
+// one of the two above functions.
 string do_strerror_r(int ev) {
     char buffer[strerror_buff_size];
+    // Preserve errno around the call. (The C++ standard requires that
+    // system_error functions not modify errno).
     const int old_errno = errno;
-    int ret;
-    if ((ret = ::strerror_r(ev, buffer, strerror_buff_size)) != 0) {
-        // If `ret == -1` then the error is specified using `errno`, otherwise
-        // `ret` represents the error.
-        const int new_errno = ret == -1 ? errno : ret;
-        errno = old_errno;
-        if (new_errno == EINVAL) {
-            std::snprintf(buffer, strerror_buff_size, "Unknown error %d", ev);
-            return string(buffer);
-        } else {
-            assert(new_errno == ERANGE);
-            // FIXME maybe? 'strerror_buff_size' is likely to exceed the
-            // maximum error size so ERANGE shouldn't be returned.
-            std::abort();
-        }
+    const char *error_message = handle_strerror_r_return(
+        ::strerror_r(ev, buffer, strerror_buff_size), buffer);
+    // If we didn't get any message, print one now.
+    if (!error_message[0]) {
+      std::snprintf(buffer, strerror_buff_size, "Unknown error %d", ev);
+      error_message = buffer;
     }
-    return string(buffer);
+    errno = old_errno;
+    return string(error_message);
 }
 #endif
-
 } // end namespace
+#endif
 
 string
 __do_message::message(int ev) const
@@ -258,6 +290,7 @@ __throw_system_error(int ev, const char* what_arg)
 #else
     (void)ev;
     (void)what_arg;
+    _VSTD::abort();
 #endif
 }