The mangling of generic typealiases was using the underlying type’s generic
arguments rather than the generic arguments for the typealias itself.
Directly encode the generic arguments from the substitution map instead.
Also address some related issues with remangling generic typealiases.
Fixes rdar://problem/41444286.
Protocol name mangling didn’t always go through a path that allowed the use
of standard substitutions. Enable standard substitutions for protocol name
manglings where they make sense.
Removes ~277k from the standard library binary size.
This makes resolving mangled names to nominal types in the same module more efficient, and for eventual secrecy improvements, also allows types in the same module to be referenced from mangled typerefs without encoding any source-level name information about them.
A "retroactive" protocol conformance is a conformance that is provided
by a module that is neither the module that defines the protocol nor
the module that defines the conforming type. It is possible for such
conformances to conflict at runtime, if defined in different modules
that were not both visible to the compiler at the same time.
When mangling a bound generic type, also mangle retroactive protocol
conformances that were needed to satisfy the generic requirements of
the generic type. This prevents name collisions between (e.g.) types
formed using retroactive conformances from different modules. The
impact on the size of the mangling is expected to be relatively small,
because most conformances are not retroactive.
Fixes the ABI part of rdar://problem/14375889.
This new format more efficiently represents existing information, while
more accurately encoding important information about nested generic
contexts with same-type and layout constraints that need to be evaluated
at runtime. It's also designed with an eye to forward- and
backward-compatible expansion for ABI stability with future Swift
versions.
Except GenericEnvironment.h, because you can't meaningfully use a
GenericEnvironment without its signature. Lots less depends on
GenericSignature.h now. NFC
- Allow them to use substitutions.
- Consistently use 'a' as a mangling operator.
- For generic typealiases, include the alias as context for any generic
parameters.
Typealiases don't show up in symbol names, which always refer to
canonical types, but they are mangled for debug info and for USRs
(unique identifiers used by SourceKit), so it's good to get this
right.
This can show up when trying to generate USRs for a document with
errors in it. This isn't a great answer because the names it generates
aren't unique (there may be more than one nameless entity with the
same type), but it at least generates valid mangled names.
When generating mangled names for purposes other than USRs, nameless
entities are now checked for by an assertion.
This fixes a crash while building the Swift standard library when
partial specializations are enabled.
Eventually we should get rid of needing the DeclContext in the mangled
typename at all, and this is one step towards that goal.
rdar://problem/31253373
Simply mangling the derived method is no longer sufficient. Now also
mangle the base method, so that eventually we handle this sort of
scenario:
class Base {
// introduces: Base.method
func method(_: Int, _: Int) {}
}
class First : Base {
// overrides: Base.method
// introduces: First.method
override func method(_: Int?, _: Int) {}
}
class Second : First {
// overrides: Base.method, First.method
// introduces: Second.method
override func method(_: Int?, _: Int?) {}
}
Here, the override of Base.method by Second.method and the
override of First.method by Second.method require distinct
manglings even though the derived method (Second.method) is
the same in both cases.
Note that while the new mangling is longer, vtable thunks are
always emitted with private linkage, so with the exception of
the standard library which is built with -sil-serialize-all
they will not affect the size of dylibs.
The standard library itself has very few classes so it doesn't
matter there either.
This patch doesn't actually add any support to introduce new
vtable entries for methods that override; this is coming up
next.
In the following example, the two declarations should have
the same mangled type:
protocol P {
associatedtype P
}
func f1<T : P>(_: T) -> T.P where T.P == Int {}
func f2<T : P>(_: T) -> Int where T.P == Int {}
To ensure this is the case, canonicalize the entire
GenericFunctionType before taking it apart, instead of
canonicalizing structural components of it.
Only those types can be de-mangled by the ObjC runtime anyway.
Also move this mangling logic into the ASTMangler class. This avoids keeping the old mangler around just for that purpose.
This is what ‘_Tt’ was in the old mangling.
Maybe we don’t need this eventually. But currently at least swift-ide-test relies on having a special mangling for such symbols
Following classes provide symbol mangling for specific purposes:
*) Mangler: the base mangler class, just providing some basic utilities
*) ASTMangler: for mangling AST declarations
*) SpecializationMangler: to be used in the optimizer for mangling specialized function names
*) IRGenMangler: mangling all kind of symbols in IRGen
All those classes are not used yet, so it’s basically a NFC.
Another change is that some demangler node types are added (either because they were missing or the new demangler needs them).
Those new nodes also need to be handled in the old demangler, but this should also be a NFC as those nodes are not created by the old demangler.
My plan is to keep the old and new mangling implementation in parallel for some time. After that we can remove the old mangler.
Currently the new implementation is scoped in the NewMangling namespace. This namespace should be renamed after the old mangler is removed.
