- Introduced a new helper class FunctionSignaturePartialSpecializer which provides most of the functionality required for producing a specialized generic signature based on the provided substitutions or requirements. The class consists of many small functions, which should make it easier to understand the code.
- Added a full support for partial specialization of generic parameters with generic substitutions (use flag `-Xllvm -sil-partial-specialization-with-generic-substitutions` to enable it)
- Removed the simpler version of the partial specializer which could partially specialize only generic parameters with non-generic substitutions. It is not needed anymore, because we can handle any substations now when performing the partial specialization.
- The functionality used by the EagerSpecializer to implement the partial specializations required by @_specialize is expressed in terms of FunctionSignaturePartialSpecializer as well. The code implementing it is much smaller now.
Partial specialization of generic parameters with generic substitutions is fully functional, but it is disabled by default, because it needs some tweaks when it comes to compile times and size of produced code. These issues will be addressed in the subsequent commits.
There were two bugs:
- A proper GenericContextScope was not set for type lowering
- Interface types were not mapped to contextual types before using them in SIL instructions
In case of a full specialization, the specialized function does not have a generic signature. Therefore there is no need to build it.
This speeds up the compilation by avoiding doing a useless work.
remapRequirements() was doing a whole lot of substitution work by
itself that the GenericSignatureBuilder is already capable of
doing. Use the GSB's functionality instead.
Rather than true (an error occurred) or false (the constraint was
resolved), introduce ConstraintResult to better model what
happened. NFC for now, but the intent here is to report unresolved
constraints through this mechanism.
Also, add a third [serializable] state for functions whose bodies we
*can* serialize, but only do so if they're referenced from another
serialized function.
This will be used for bodies synthesized for imported definitions,
such as init(rawValue:), etc, and various thunks, but for now this
change is NFC.
Use -sil-partial-specialization-with-generic-substitutions to enable the partial specialization even in cases of substitutions containing generic replacement types.
This improves the existing logic which is used to stop specialization for types that are too big to handle. It catches some pathological cases which hang the compiler.
Fixes rdar://30938882
Re-applying this commit, which was speculatively reverted. It turned out that that performance tests issues were unrelated.
This improves the existing logic which is used to stop specialization for types that are too big to handle. It catches some pathological cases which hang the compiler.
Fixes rdar://30938882
Partial specialization is disabled by default. Use -sil-partial-specialization to enable it.
Use -sil-partial-specialization-with-generic-substitutions to enable the partial specialization even in cases of substitutions containing generic replacement types.
