- Add newlines where missing to match sys/errno.h error groups separation
- Prefer single-line comments to C-style comments
- Align most comments to same column
- Add comment following #endif at EOF to show what it ends
- Remove extraneous whitespace
This is a staging attribute that will eventually mean "fixed-contents"
for structs and "closed" for enums, as described in
docs/LibraryEvolution.rst.
This is pretty much the minimal set of types that must be fixed-layout,
because SILGen makes assumptions about their lowering.
If desired, some SILGen refactoring can allow some of these to be
resilient. For example, bridging value types could be made to work
with resilient types.
When we're not serializing SIL for all function bodies, @_transparent
functions can only reference internal functions that are declared
@_versioned, otherwise there's no serialized body and no public entry
point, so any client that inlines the @_transparent function will
not be able to link.
This patch adds the minimum set of @_versioned declarations to allow
a non-optimized build of the standard library and overlays.
Recall that this attribute is just a temporary hack to make progress
on building the standard library with resilience enabled.
Once availability and resilience learn about each other, @_versioned
will be replaced by having an availability annotation on an internal
declaration. Invariants will be diagnosed by Sema instead of asserting
in the SIL verifier.
Finally, the set of "internal but available" declarations will
eventually be audited instead of determined by experimentation.
This almost closes out https://bugs.swift.org/browse/SR-267.
The remaining issue is an interaction between SIL optimizations and
serialization that will be fixed with some upcoming changes to the
optimizer.
