In case of cross-module-optimizations it can happen that a private global variable is changed to public,
but it's declaration is not available in the module file.
It seems really unfortunate that we use SILCloner to, basically,
implement a recursive visitor of the types used in a SIL function,
but apparently it's what we do.
Fixes#72117.
* Add a new flag -experimental-package-cmo that requires -experimental-allow-non-resilient-access.
* Support serializing package decls for CMO in package if enabled.
* Only applies to default mode CMO.
* Unlike the existing CMO, package CMO can be built with -enable-library-evolution as package
modules are required to be built together in the same project.
* Create hasPublicOrPackageVisibility to opt in for package decls; needed for CMO, SILVerifier,
and other call sites that verify or determine codegen.
Resolves rdar://121976014
For example:
```
public static var privateFunctionPointer: (Int) -> (Int) = { $0 }
```
Fixes a verifier crash and/or undefined symbol error
rdar://99493254
This is a follow-up of 1dfb3b1a2a.
We need to be more conservative about types as for functions, because types can also "produce" symbols, like direct field offsets, etc.
rdar://96953318
If we are emitting a TBD file, the TBD file only contains public symbols of this module.
But not public symbols of imported modules which are statically linked to the current binary.
This prevents referencing public symbols from other modules which could (potentially) linked statically.
Unfortunately there is no way to find out if another module is linked statically or dynamically, so we have to be conservative.
Fixes an unresolved-symbol linker error.
rdar://89364148
* rename the CrossModuleSerializationSetup pass to simply CrossModuleOptimization
* remove the CMO specific serializer pass. Instead run the CrossModuleSerializationSetup pass directly before the standard serializer pass.
* correctly handle shared functions (e.g. specializations)
* refactoring
Referenced functions within the initializer of a SILGlobalVariable must be handled like referenced functions in other functions.
Fixes an assert crash when compiling with -cross-module-optimization
The check for implementationOnly imports was already done for types, but it was missing for functions.
Fixes a crash when implementationOnly-importing a C module.
https://bugs.swift.org/browse/SR-15048
rdar://81701218
