We don't want objc_getClass and NSClassFromString to be able to feed arbitrary symbolic reference
pointers into the Swift runtime. Fixes rdar://problem/54724618.
This is a one-to-many cache that's more speculative than the cache mapping mangled names to context descriptors. Entries found in the cache need to be verified for a match before they can be returned. However, this allows scanning conformance records up front and building up the cache in one scan rather than performing an expensive scan of all conformance records every time the mangled name cache misses.
rdar://problem/53560010
When looking for a context descriptor for a protocol extension, we
search based on the mangled name--"x", a generic type parameter with
depth and index 0--and are guaranteed to fail because there is no such
concrete type. However, _findContextDescriptor will fail very slowly,
spinning through all of the types and conformances in all of the
loaded images. Moreover, negative results aren't cached, so this can
happen repeatedly.
Short-circuit _findContextDescriptor when it receives a dependent
generic type parameter type, avoiding the expensive search when it
will find nothing.
Potential fix for rdar://problem/53560010.
Generic parameters for a context are normally classified as "key",
meaning they have actual metadata provided at runtime, or non-key,
meaning they're derivable from somewhere else. However, a nested
context or constrained extension can take what would be a "key"
parameter in a parent context and make it non-key in a child context.
This messes with the mapping between the (depth, index) representation
of generic parameters and the flat list of generic arguments. Fix this
by (1) consistently substituting out extension contexts with the
contexts of the extended types, and (2) using the most nested context
to decide which parameters are key, instead of the context a parameter
was originally introduced in.
Note that (1) may have problems if/when extensions start introducing
their /own/ generic parameters. For now I tried to be consistent with
what was there.
rdar://problem/52364601
This one’s screwily specific--if you have:
* a private generic type,
* with a nested generic type in it,
* and the nested type conforms to a protocol with an associated type,
* and that associated type’s witness is a generic type,
* and some of the witness type’s generic parameters are generic parameters of the nested type,
demangling would fail. The problem is that the substitution machinery in the runtime would consider there to be three, not two, generic context depths involved. Depth 1, which should correspond to the nested type, would instead have no generic parameters. The fix is to skip over depths with zero generic parameters.
Fixes <rdar://problem/47773183>.
We could introduce non-nominal-type context descriptors, such as those for opaque declarations,
which are also interesting to be able to look up for reflection or remote purposes. This should be
a backward compatible change with old runtimes, which always ignore any context descriptor kind
they don't know about.
In protocol extensions, and in the future parameterized extensions, have their own generic arguments
independent of an originating nominal type's formal generic parameters. Instead of crashing, handle
this gracefully. rdar://problem/50038754
This caused an issue where the runtime was unable to find subclasses of
resilient subclasses of NSObject until they were first registered by their
sugared name with NSClassFromString or were instantiated directly.
rdar://48892003
Extract common code from the old and new remangler into a common base class.
This lets the old remangler benefit from the changes I did recently in the new remangler.
Instead of capturing SubstGenericParametersFromMetadata and SubstGenericParametersFromWrittenArgs by value, capture by reference.
This avoids those instances to be copied and thus avoids a lot of mallocs.
SR-10028
rdar://problem/48575729
This dramatically reduces the number of needed malloc calls.
Unfortunately I had to add the implementation of SmallVectorBase::grow_pod to the runtime, as we don't link LLVM. This is a bad hack, but better than re-inventing a new SmallVector implementation.
SR-10028
rdar://problem/48575729
This is done by disallowing nodes with children to also have index or text payloads.
In some cases those payloads were not needed anyway, because the information can be derived later.
In other cases the fix was to insert an additional child node with the index/text payload.
Also, implement single or double children as "inline" children, which avoids needing a separate node vector for children.
All this reduces the needed size for node trees by over 2x.
Note that I've called out a couple of suspicious places where we
are requesting abstract metadata for superclasses but probably
need to be requesting something more complete.
MetadataLookup gives special treatment to imported Objective-C classes,
since there's no nominal type descriptor and metadata is obtained
directly by calling into the Objective-C runtime.
Remote reflection also gives special treatment to imported Objective-C
classes; they don't have field descriptors.
However, the ASTDemangler needs to treat them like ordinary classes,
in particular it wants to preserve the generic arguments here so that
we can round-trip debug info.
If we nest a type inside a local context inside a generic type,
we have to look through the local context(s) to find the outer
generic type when stripping off generic arguments.
We don't support nominal types inside generic local context
right now, but this can happen with type aliases.
Debug info uses a special mangling where type aliases can be
represented without being desugared; attempt to reconstruct
the TypeAliasType in this case.
We were creating a local Demangler instance, demangling a type name
using it, and then returning one of the resulting nodes to the caller.
Fixes rdar://problem/46817009.
This can be used by compiler-generated code as a size optimization for metadata access, using a
mangled name instead of possibly many open-coded metadata calls. It can also allow reflection
libraries outside of the standard library to turn type reference strings into in-process metadata
pointers in a robust way. rdar://problem/46451849
libobjc needs to look up classes by name. Some Swift classes, such as
instantiated generics and their subclasses, are created only on demand.
Now a by-name lookup from libobjc counts as a demand for those classes.
rdar://problem/27808571
