From: Zachary Turner <zturner@google.com>
Date: Thu, 14 Dec 2017 19:11:28 +0000 (+0000)
Subject: Only use is_trivially_copyable if we know it's safe to do so.
X-Git-Tag: android-x86-7.1-r4~7215
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=b9a44ec3ca3f9d5cfb01bbcd64a0e015e05aaaa3;p=android-x86%2Fexternal-llvm.git

Only use is_trivially_copyable if we know it's safe to do so.

Apparently this isn't present on older versions of libstdc++, so
it causes some builds to fail.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320733 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/DebugInfo/CodeView/TypeHashing.h b/include/llvm/DebugInfo/CodeView/TypeHashing.h
index af7af05ac2d..74133753370 100644
--- a/include/llvm/DebugInfo/CodeView/TypeHashing.h
+++ b/include/llvm/DebugInfo/CodeView/TypeHashing.h
@@ -132,11 +132,15 @@ struct GloballyHashedType {
     return Hashes;
   }
 };
+#if defined(_MSC_VER)
+// is_trivially_copyable is not available in older versions of libc++, but it is
+// available in all supported versions of MSVC, so at least this gives us some
+// coverage.
 static_assert(std::is_trivially_copyable<GloballyHashedType>::value,
               "GloballyHashedType must be trivially copyable so that we can "
               "reinterpret_cast arrays of hash data to arrays of "
               "GloballyHashedType");
-
+#endif
 } // namespace codeview
 
 template <> struct DenseMapInfo<codeview::LocallyHashedType> {