This is technically a source break, but the @_fixed_layout attribute
is not official yet. If anyone really cares, we can make this
conditional on -swift-version 5 later, but I'd rather not.
This change is necessary so that we can give property initializers
non-public linkage. Currently they are public, because they can be
referenced from inlinable initializers.
Now that property initializers inside a @_fixed_layout type can
only reference public symbols, they no longer have to be public,
but making that change requires a bit more work.
Replace the use of -sil-inline-threshold with @inline(never) on specific
functions. This is required in some cases in order to remove the generic
specialization pass and allow the inliner to do the specialization
instead (specifically the cases where the parameter is 0, which causes
us to exit the inliner immediately).
Also add public in some places to ensure that we do not toss out
functions before we even make it to the inliner (once the standalone
generic specialization pass is removed).
Swift SVN r31126
In most cases this means adding @public to things that get serialized;
in a few cases it means using a modern public stdlib API instead of
a legacy thing I was trying to keep @internal.
Swift SVN r19350
