[libc-commits] [libc] [libc] Allow RPC interface to be compiled with MSVC (PR #190483)

[Joseph Huber via libc-commits]

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@@ -20,10 +20,24 @@
 
 #include "rpc_util.h"
 
-namespace rpc {
-
 /// Use scoped atomic variants if they are available for the target.
 #if !__has_builtin(__scoped_atomic_load_n)
+#ifdef _MSC_VER // MSVC atomic support.
+#include <intrin.h>
+#define RPC_TYPEOF(x) rpc::remove_reference_t<decltype(x)>
+#define __scoped_atomic_load_n(src, ord, scp)                                  \
+  (*(const volatile RPC_TYPEOF(*(src)) *)(src))
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jhuber6 wrote:

That's what I thought but it's used in practice? Though this might be behavior gated behind their extended volatile so I'm not sure if it works in every case https://learn.microsoft.com/en-us/cpp/build/reference/volatile-volatile-keyword-interpretation?view=msvc-170.

I'm going to double check this.

https://github.com/llvm/llvm-project/pull/190483