Now that every foreign type has a type context descriptor, we can use that for a uniquing key instead of a dedicated mangled string, saving some code size especially in code that makes heavy use of imported types. rdar://problem/37537241
Change generic witness table instantiation to use a more lightweight
entry scheme that allocates the witness table as part of the entry.
In contrast, change generic metadata instantiation to use a more
straightforward allocation scheme where the metadata is a totally
independent allocation.
This is preparation for proper cyclic-dependency handling.
Check that an ``withoutActuallyEscaping(noescape_closure) { // scope}`` closure
has not escaped in the scope using the ``is_escaping_closure %closure``
instruction.
rdar://35525730
Will be used to verify that withoutActuallyEscaping's block does not
escape the closure.
``%escaping = is_escaping_closure %closure`` tests the reference count. If the
closure is not uniquely referenced it prints out and error message and
returns true. Otherwise, it returns false. The returned result can be
used with a ``cond_fail %escaping`` instruction to abort the program.
rdar://35525730
The allocation phase is guaranteed to succeed and just puts enough
of the structure together to make things work.
The completion phase does any component metadata lookups that are
necessary (for the superclass, fields, etc.) and performs layout;
it can fail and require restart.
Next up is to support this in the runtime; then we can start the
process of making metadata accessors actually allow incomplete
metadata to be fetched.
The layout changes to become relative-address based. For this to be
truly immutable (at least on Darwin), things like the RO data patterns
must be moved out of the pattern header. Additionally, compress the
pattern header so that we do not include metadata about patterns that
are not needed for the type.
Value metadata patterns just include the metadata kind and VWT.
The design here is meant to accomodate non-default instantiation
patterns should that become an interesting thing to support in the
future, e.g. for v-table specialization.
This is simpler, because the native form of that last argument is: a
pointer to a buffer (*) of pointers (*) to witness tables, which is
modelled as a buffer of void *s. Thus, void ***.
Change the "metadata base offset" variable into a "class metadata bounds"
variable that contains the base offset and the +/- bounds on the class.
Link this variable from the class descriptor when the class has a resilient
superclass; otherwise, store the +/- bounds there. Use this variable to
compute the immediate-members offset for various runtime queries. Teach the
runtime to fill it in lazily and remove the code to compute it from the
generated code for instantiation. Identify generic arguments with the start
of the immediate class metadata members / end of the {struct,enum} metadata
header and remove the generic-arguments offset from generic type descriptors.
Minimize the generic class metadata template by removing the
class header and base-class members. Add back the set of
information that's really required for instantiation.
Teach swift_allocateGenericClass how to allocate classes without
superclass metadata. Reorder generic initialization to establish
a stronger phase-ordering between allocation (the part that doesn't
really care about the generic arguments) and initialization (the
part that really does care about the generic arguments and therefore
might need to be delayed to handle metadata cycles).
A similar thing needs to happen for resilient class relocation.
This is yet another waypoint on the path towards the final
generic-metadata design. The immediate goal is to make the
pattern a private implementation detail and to give the runtime
more visibility into the allocation and caching of generic types.
The dumper method dumps:
1. The container's metadata pointer.
2. A pointer to the container's value.
3. Whether or not said value is stored inline in the container.
This provides a general overview that can be used even when working with SIL
code in the debugger by grabbing a pointer to swift Anys and then calling the
c++ any method upon them.
The verifier is intended to be used in conjunction with ASAN for maximum
effect to catch use-after-frees of existential boxes.
While implementing this I refactored some code from ExistentialTypeMetadata into
methods on OpaqueExistentialContainer. ExistentialTypeMetadata just calls these
methods now instead of implementing the code inline.
All of the information contained by this field (list of property names)
is already encoded as part of the field reflection metadata and
is accessible via `swift_getFieldAt` runtime method.
Use information from reflection section of the binary to lookup
type field info such as name and it's type and return it using
new `swift_getFieldAt` method based on nominal type and field index.
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.
When evaluating whether a given type conforms to a protocol, evaluate the
conditional requirements and pass the results to the witness table
accessor function. This provides the ability to query conditional
conformances at runtime, and is the last major part of implementing
SE-0143.
The newly-added unlock/lock dance in the conformance lookup code is a
temporary stub. We have some ideas to do this better.
Fixes rdar://problem/34944655.
Extend protocol conformance descriptors with two more bits of information:
* For retroactive conformances, add the module in which the conformance
occurs. This will eventually be used for error reporting/ambiguity
resolution when retroactive conformances collide.
* For conditional conformances, add the conditional requirements. We need
these for runtime evaluation of conditional conformances.
RelativeDirectPointerIntPair uses the alignment of the pointer to determine
how many low bits are in the tiny integer value. This led to an inconsistency
between the runtime view of TargetGenericParamRef (which expected the
Boolean flag to be in the lower two bits) and the compiler's view
(which put the Boolean flag in the lowest bit), causing crashes.
Extend support for mapping a mangled name -> type metadata to include
support for checking protocol conformance requirements, using the
encoding of generic requirements that is now available within context
descriptors. For example, this allows
_typeByMangledName(mangled-name-of-Set<Int>) to construct proper type
metadata, filling in the Int: Hashable requirement as appropriate.
We dump the following information:
1. The Kind.
2. Pointer to the value witnesses.
3. Pointer to the class object if one is available.
4. Pointer the type context description if one is available.
5. Pointer to the generic arguments if one is available.
This makes it significantly easier to poke around Metadata.
rdar://34222540
This is useful when trying to track down data corruption in the runtime. I am
currently running into such issues with the +0-all-arg work, so I am adding
stuff like this to help debug this issue and future such issues.
rdar://34222540
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.
* Remove RegisterPreservingCC. It was unused.
* Remove DefaultCC from the runtime. The distinction between C_CC and DefaultCC
was unused and inconsistently applied. Separate C_CC and DefaultCC are
still present in the compiler.
* Remove function pointer indirection from runtime functions except those
that are used by Instruments. The remaining Instruments interface is
expected to change later due to function pointer liability.
* Remove swift_rt_ wrappers. Function pointers are an ABI liability that we
don't want, and there are better ways to get nonlazy binding if we need it.
The fully custom wrappers were only needed for RegisterPreservingCC and
for optimizing the Instruments function pointers.
