Driver: default to `unsigned int` `wchar_t` for ARM

AAPCS and AAPCS64 mandate that `wchar_t` with `-fno-short-wchar` is an
`unsigned int` rather than a `signed int`.  Ensure that the driver does
not flip the signedness of `wchar_t` for those targets.

Add additional tests to ensure that this does not regress.

llvm-svn: 316858

1 files changed, 6 insertions, 1 deletions

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index adaf39abc5f..c1c8813cc42 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -2622,8 +2622,13 @@ static void RenderCharacterOptions(const ArgList &Args, const llvm::Triple &T,
       CmdArgs.push_back("-fwchar-type=short");
       CmdArgs.push_back("-fno-signed-wchar");
     } else {
+      bool IsARM = T.isARM() || T.isThumb() || T.isAArch64();
       CmdArgs.push_back("-fwchar-type=int");
-      CmdArgs.push_back("-fsigned-wchar");
+      if (IsARM && !(T.isOSWindows() || T.getOS() == llvm::Triple::NetBSD ||
+                     T.getOS() == llvm::Triple::OpenBSD))
+        CmdArgs.push_back("-fno-signed-wchar");
+      else
+        CmdArgs.push_back("-fsigned-wchar");
     }
   }
 }