Add a package serialization bit to Module for SIL verifier in Package CMO mode.

[elsh]

During Package CMO, SIL cloning happens during which
SILOptions::EnableSerializePackage info is lost.

SILVerifier needs this info to determine whether resilience
can be bypassed for decls serialized in a resiliently
built module when Package CMO optimization enabled.

This PR adds SerializePackageEnabled bit to Module format
and uses that in SILVerifier.

Resolves rdar://126157356

[elsh]

@swift-ci smoke test

[aschwaighofer]

The resilience expansion of a ‘serialized’ function is always minimal. (See getResilienceExpansion() in SILFunction.h)

by adding this condition (‘isSerialized()‘) we will by pass the check even in regular resilient mode (no package cmo enabled). I don’t think this is desirable.

Can you restrict this bypass to only when the current module is in the same package?

[elsh]

Updated to check for that as well as whether module was built resiliently when serialized.

[aschwaighofer]

Instead of:

auto serializedInResilientModule = M->isResilient() &&
                                     isSerialized &&
                                     D->getModuleContext()->inSamePackage(M);

I think we want to test the scenario where the Decl D is in a module that allows non resilient access from within the package boundary and we are accessing it from within the package boundary via a binary .swiftmodule (build from source). There is two cases:

• within the same module (M == D, module was compiled from source and allows resilient access)
• the function was deserialized and is now in a different module (M != D, D allows non-resilience access, M and D are in the same package and M has bypass resilience and enabled)

I think that would make the check something like:

auto accessingModule = M;
bool byPassResilienceCheck =
  (D->getModuleContext()->allowNonResilientAccess() && D == M) || // Same module case
  (F.getASTContext().LangOpts.EnableBypassResilienceInPackage && // Different modules case
   D->getModuleContext()->inSamePackage(M) &&                  
   D->getModuleContext()->allowNonResilientAccess());

[elsh]

Had to add SerializePackageEnabled bit to Module; the SILOpts.EnableSerializePackage info gets lost during SIL cloning stage of Package CMO, so it needed to be serialized to the binary module. It's added to this SILVerifier check function along with others we discussed.

[elsh]

@swift-ci smoke test

[elsh]

@swift-ci smoke test

[elsh]

@swift-ci smoke test

[aschwaighofer]

LGTM. Thank you