This PR is another attempt at landing #76903. The changes compared to
the original PR:
* Instead of increasing the size of SILDeclRef, store the necessary type
information in a side channel using withClosureTypeInfo.
* Rely on SGFContext to get the right ClangType
* Extend BridgingConversion with an AbstractionPattern to store the
original clang type.
* The PR above introduced a crash during indexing system modules that
references foreign types coming from modules imported as
implementation only. These entities are implementation details so they
do not need to be included during serialization. This PR adds a test
and adds logic to exclude such clang types in the serialization
process.
rdar://131321096&141786724
The thunk's parameter needs the @in_guaranteed convention if it's a
const reference parameter. However, that convention wasn't being used
because clang importer was removing the const reference from the
type and SILGen was computing the type of the parameter based on the
type without const reference.
This commit fixes the bug by passing the clang function type to
SILDeclRef so that it can be used to compute the correct thunk type.
This fixes a crash when a closure is passed to a C function taking a
pointer to a function that has a const reference struct parameter.
This recommits e074426 with fixes to
serialization/deserialization of function types. The fixes prevent clang
types of functions from being dropped during serialization.
rdar://131321096
