add comment

Author: nickdesaulniers

libc/src/setjmp/setjmp_impl.h

@@ -17,6 +17,15 @@
 
 namespace LIBC_NAMESPACE_DECL {
 
+// TODO(https://github.com/llvm/llvm-project/issues/112427)
+// Some of the architecture-specific definitions are marked `naked`, which in
+// GCC implies `nothrow`.
+//
+// Right now, our aliases aren't marked `nothrow`, so we wind up in a situation
+// where clang will emit -Wmissing-exception-spec if we add `nothrow` here, but
+// GCC will emit -Wmissing-attributes here without `nothrow`. We need to update
+// LLVM_LIBC_FUNCTION to denote when a function throws or not.
+
 #ifdef LIBC_COMPILER_IS_GCC
 [[gnu::nothrow]]
 #endif