Rather than mapping all of the builtin floating-point and vector
types down to the type metadata symbols for power-of-two integers,
map down to the type metadata symbols provided by the runtime.
This allows us to round-trip type metadata <-> mangled name for all of
the builtin types that have such symbols. When we don’t have a runtime
symbol, we will fail to link if that builtin type gets referenced.
Expose symbols for metadata for the various builtin floating point types
and vector types. This is used by the demangler to handle builtin names.
This is a narrow fix for rdar://problem/45569984 (where we couldn’t
demangle a builtin vector type). A more extensive fix will require us
to add a general runtime facility for creating opaque type metadata
with specific size/alignment/stride/uniquing name.
This runtime function doesn’t always perform instantiation; it’s how we
get a witness table given a conformance, type, and set of instantiation
arguments. Name it accordingly.
Witness table accessors return a witness table for a given type's
conformance to a protocol. They are called directly from IRGen
(when we need the witness table instance) and from runtime conformance
checking (swift_conformsToProtocol digs the access function out of the
protocol conformance record). They have two interesting functions:
1) For witness tables requiring instantiation, they call
swift_instantiateWitnessTable directly.
2) For synthesized witness tables that might not be unique, they call
swift_getForeignWitnessTable.
Extend swift_instantiateWitnessTable() to handle both runtime
uniquing (for #2) as well as handling witness tables that don't have
a "generic table", i.e., don't need any actual instantiation. Use it
as the universal entry point for "get a witness table given a specific
conformance descriptor and type", eliminating witness table accessors
entirely.
Make a few related simplifications:
* Drop the "pattern" from the generic witness table. Instead, store
the pattern in the main part of the conformance descriptor, always.
* Drop the "conformance kind" from the protocol conformance
descriptor, since it was only there to distinguish between witness
table (pattern) vs. witness table accessor.
* Internalize swift_getForeignWitnessTable(); IRGen no longer needs to
call it.
Reduces the code size of the standard library (+assertions build) by
~149k.
Addresses rdar://problem/45489388.
Extending the mangling of symbolic references to also include indirect
symbolic references. This allows mangled names to refer to context
descriptors (both type and protocol) not in the current source file.
For now, only permit indirect symbolic references within the current module,
because remote mirrors (among other things) is unable to handle relocations.
Co-authored-by: Joe Groff <jgroff@apple.com>
Collapse the generic witness table, which was used only as a uniquing
data structure during witness table instantiation, into the protocol
conformance record. This colocates all of the constant protocol conformance
metadata and makes it possible for us to recover the generic witness table
from the conformance descriptor (including looking at the pattern itself).
Rename swift_getGenericWitnessTable() to swift_instantiateWitnessTable()
to make it clearer what its purpose is, and take the conformance descriptor
directly.
When searching the superclasses at runtime, e.g., to find a suitable
protocol conformance record, also consider the superclasses of CF
types, which were recorded in the metadata but otherwise unused.
When performing the round-tripping verification for mangled type names,
make sure we resolve symbolic references to something
user-comprehensible that can be meaningfully rem angled.
Part of rdar://problem/37551850.
Place resilient witnesses in the protocol conformance descriptor,
tail-allocated after the conditional requirements, so they can be found by
reflection. Drop the resilient witness table and protocol descriptor from
the generic witness table.
Addresses rdar://problem/45228582.
Remove the compiler support for exclusivity warnings.
Leave runtime support for exclusivity warnings in non-release builds
only for unit testing convenience.
Remove a test case that checked the warning log output.
Modify test cases that relied on successful compilation in the
presence of exclusivity violations.
Fixes: <rdar://problem/45146046> Remaining -swift-version 3 tests for exclusivity
[Runtime] Fix swift_retainCount for deiniting objects and BridgeObject tagged values. Make swift_bridgeObjectRetain/Release bail out early for tagged values.
We were previously only installing the image registration helper in the shared
runtime location. When building with a static runtime, we would look in the
wrong location. Ensure that we install to both locations to repair the static
builds.
Have clients pass the requirement base descriptor to
swift_getAssociatedTypeWitness(), so that the witness index is just one
subtraction away, avoiding several dependent loads (witness table ->
conformance descriptor -> protocol descriptor -> requirement offset)
in the hot path.
The Allocations Instrument overrides swift_retain with a function that records the retain count by calling swift_retainCount. Its assert for bits.getIsDeiniting() is incorrect in that case, so remove it.
The recent change to ObjC tagged pointer bits on x86-64 also caused the various bridgeObjectRetain/Release functions to call through to swift_retain for BridgeObject tagged values on Mac. swift_retain ignored those values so there was no functional change, except when Instruments overrode it and passed them to swift_retainCount, which tried to dereference them and crashed. Modify bridgeObjectRetain/Release to bail out early again. Also modify swift_retainCount to ignore those values in case anything else expects retainCount to work on any pointer swift_retain accepts.
rdar://problem/45102538
Rather than rely on the metadata initialization function to compute and
fill in the superclass, use the mangled superclass name to construct the
superclass metadata.
Previously we had a single mask for all x86-64 targets which included both the top and bottom bits. This accommodated simulators, which use the top bit, while macOS uses the bottom bit, but reserved one bit more than necessary on each. This change breaks out x86-64 simulators from non-simulators and reserves only the one bit used on each.
rdar://problem/34805348 rdar://problem/29765919
Introduce a sanity check verifying that we can demangle the superclass
of a class when forming type metadata, and that the result matches the
compiler-provided superclass metadata.
The superclass descriptor reference in class context descriptors is only used
for metadata bound computations when the superclass is resilient. Only
include the superclass descriptor reference when the class has a resilient
superclass, using a trailing record. It’s a tiny space savings for
classes that don’t have resilient superclasses.
The functions in LibcShims are used externally, some directly and some through @inlineable functions. These are changed to SWIFT_RUNTIME_STDLIB_SPI to better match their actual usage. Their names are also changed to add "_swift" to the front to match our naming conventions.
Three functions from SwiftObject.mm are changed to SPI and get a _swift prefix.
A few other support functions are also changed to SPI. They already had a prefix and look like they were meant to be SPI anyway. It was just hard to notice any mixup when they were #defined to the same thing.
rdar://problem/35863717
This is the scheme used for metadata caches elsewhere, and it
eliminates the need to check the metadata state along the hot path of
swift_getAssociatedTypeWitness().
Encode default associated type witnesses using a sentinel prefix byte
(0xFF) in the mangled name rather than as a second low bit on the
reference. Align all of the mangled names used for type references to
2 bytes (so we get that low bit regardless) and separate the symbol
names for default associated type witnesses vs. other kinds of
metadata or reflection metadata.
Indicate whether a particular associated type witness is a default (whose
mangled name is relative to the protocol) vs. being supplied as part of the
conformance (whose mangled name is relative to the conforming type). The
use of pointer identity to distinguish these cases can fail due to the
coalescing of these linker symbols.
When producing an associated type witness from a mangled name, adjust the
conforming type metadata to find the original conforming type, which may
be a superclass of the conforming type given.
Associated type witnesses in a witness table are cache entries, which are
updated by the runtime when the associated types are first accessed. The
presence of an associated type witness that involves type parameters requires
the runtime to instantiate the witness table; account for that in the runtime.
The presence of any associated type witness makes the witness table
non-constant.
Rather than storing associated type metadata access functions in
witness tables, initially store a pointer to a mangled type name.
On first access, demangle that type name and replace the witness
table entry with the resulting type metadata.
This reduces the code size of protocol conformances, because we no
longer need to create associated type metadata access functions for
every associated type, and the mangled names are much smaller (and
sharable). The same code size improvements apply to defaulted
associated types for resilient protocols, although those are more
rare. Witness tables themselves are slightly smaller, because we
don’t need separate private entries in them to act as caches.
On the caller side, associated type metadata is always produced via
a call to swift_getAssociatedTypeWitness(), which handles the demangling
and caching behavior.
In all, this reduces the size of the standard library by ~70k. There
are additional code-size wins that are possible with follow-on work:
* We can stop emitting type metadata access functions for non-resilient
types that have constant metadata (like `Int`), because they’re only
currently used as associated type metadata access functions.
* We can stop emitting separate associated type reflection metadata,
because the reflection infrastructure can use these mangled names
directly.
When demangling a symbolic reference to a nested generic type, the
demangle-to-metadata path will be given all levels of generic arguments at
once. Cope with this in the demangling-to-metadata path.
Eventually, we would like to switch all clients over to take all
levels of generic arguments at once.
When forming metadata for a nested generic type, gather all of the
generic arguments from the parent type “as written”, so that we can directly
map generic parameters to those generic arguments when they occur within
requirements. This allows us to demangle nested types within extensions
that have same-type constraints on generic parameters into type metadata.
Fixes rdar://problem/37170296.
At the moment the location being reported is inside the standard
library, which is not very helpful. Instead, the location should point
at the `try!` expression in the application code.
Fixes: rdar://problem/21407683
When mapping from type metadata to a demangle tree, fill in the complete
set of generic arguments. Most of the effort here is in dealing with
extensions that involve same-type constraints on a generic parameter, e.g.,
extension Array where String == Element { }
extension Dictionary where Key == Value { }
In such cases, the metadata won’t contain generic arguments for every
generic parameter. Rather, the generic arguments for non-key generic
parameters will need to be computed based on the same-type requirements
of the context. Do so, and eliminate the old hacks that put the generic
arguments on the innermost type. We don’t need them any more.
Part of rdar://problem/37170296.
