Non-generic classes with resilient ancestry do not have statically-emitted
metadata, so we can now emit an Objective-C resilient class stub instead.
Also, when emitting an Objective-C category, reference the class stub if
the class has resilient ancestry; previously this case would hit an assert.
Note that class stubs always start with a zero word, with the address point
pointing immediately after. This works around a linker issue, where the
linker tries to coalesce categories and gets confused upon encountering a
class stub.
This consolidates the various doesClassMetadataRequire*() checks, making
them more managable.
This also adds a forth state, ClassMetadataStrategy::Update. This will be used
when deploying to the new Objective-C runtime. For now it's not plumbed through.
Progress on <rdar://problem/47649465>.
If a class has a backward deployment layout:
- We still want to emit it using the FixedClassMetadataBuilder.
- We still want it to appear in the objc_classes section, and get an
OBJC_CLASS_$_ symbol if its @objc.
- However, we want to use the singleton metadata initialization pattern
in the metadata accessor.
- We want to emit metadata for all field types, and call the
swift_updateClassMetadata() function to initialize the class
metadata.
For now, this function just performs the idempotent initialization of
invoking a static method on the class, causing it to be realized with
the Objective-C runtime.
- doesClassMetadataRequireRelocation() -- returns true if we must
allocate new metadata at runtime and fill it in, because the class
has multiple instantiations (generic case) or because the total size
of the metadata is not known at compile time (resilient ancestry).
- doesClassMetadataRequireInitialization() -- weaker condition than
the above. It's true if the metadata must be relocated, but it is
also true if the metadata has otherwise fixed size but must be
filled in dynamically. This occurs if the class has generic
ancestry but is itself not generic, or if the class has
resiliently-sized fields, or missing members.
For now, we don't actually care about the distinciton anywhere,
because we cannot do in-place initialization of class metadata yet.
We’re not using this parameter, and don’t expect to do so in the future,
so remove it. Also fold away TypeBase::usesNativeReferenceCounting()
and irgen::getReferenceCountingForType(), both of which are trivial.
When emitting fixed class metadata, we emit field offsets for all fields,
including those from superclasses, if any.
Get the ClassLayout for the correct class before looking up a field that
might potentially belong to a superclass. Soon, I'm going to slim down
ClassLayout instances to only store the fields belonging to the class
itself, removing the InheritedStoredProperites array altogether.
TypeBase::usesNativeReferenceCounting() was doing a lot of work to
find the class that a type refers to, then determine whether it
would use the native reference-counting scheme. Its primary caller
in IRGen would use an overly-conservative approximation to decide
between the “Objective-C” and “unknown” cases, which resulted in
uses of “unknown” reference counting for some obviously-ObjC cases
(e.g., values of “NSObject”).
Moreover, the approximation would try to call into the type checker
(because it relied unnecessarily on the superclass *type* of a class
declaration), causing an assertion.
Fixes rdar://problem/42828798.
Abstract type/heap metadata access goes into MetadataRequest.
Metadata access starting from a heap object goes into GenHeap.
Accessing various components of class metadata goes into GenClass
or MetadataLayout.
The alignment of tail allocated elements was not considered in the allocation call. This caused problems for alignments > 16 bytes.
rdar://problem/37470003
Only foreign classes and other imported types were making use of the
type metadata reference form in conformance records. Switch those over
to using nominal type descriptors, so we're using nominal type
descriptors for everything possible.
Only Objective-C-defined classes use a different representation now.
Following up on the fixes for rdar://problem/35330067. If a class inherits a class from another module with missing fields, we need to treat its size and alignment as opaque, just like the base class itself. We also need to lay out such class at runtime, since we don't know the size, alignment, or field offsets at compile time; relying on the ObjC runtime alone will slide the ivar offsets, but not the Swift instance size and alignment. Fixes rdar://problem/35747485.
To get the full benefit of dyld3 on Darwin platforms, pointer relocations need to be pointer-aligned, which unfortunately requires growing some key path data structures a little bit. This does tidy up some code that had to hack around our lack of unaligned load/store operations on UnsafeRawPointer, at least. While we're here, we can also simplify the identification strategy for reabstracted stored properties; we only need the property index to identify, not the absolute offset. rdar://problem/32318829
We need to use the ivar offset variables in this case, since the Swift field offset vector doesn't pick up the adjusted offsets from the ObjC runtime. Fixes SR-5036 | rdar://problem/32488871.
This gives big code size wins for unused types and also for types, which are never used in a generic context.
Also it reduces the amount of symbols in the symbol table.
The size wins heavily depend on the project. I have seen binary size reductions from 0 to 20% on real world projects.
rdar://problem/30119960
This is NFC in intent, but I had to restructure the code to emit more
of the lists "inline", which means I inevitably altered some IRGen
emission patterns in ways that are visible to tests:
- GenClass emits property/ivar/whatever descriptors in a somewhat
different order.
- An ext method type list is now emitted as just an array, not a struct
containing only that array.
- Protocol descriptors are no longer emitted as packed structs.
I was sorely tempted to stop using packed structs for all the metadata
emission, but didn't really want to update that many tests in one go.
It's the same thing as for alloc_ref: the optional [tail_elems ...] attribute specify the tail elements to allocate.
For details see docs/SIL.rst
This feature is needed so that we can allocate a MangedBuffer with alloc_ref_dynamic.
The ManagedBuffer.create() function uses the dynamic self type to create the buffer instance.
The new instructions are: ref_tail_addr, tail_addr and a new attribute [ tail_elems ] for alloc_ref.
For details see docs/SIL.rst
As these new instructions are not generated so far, this is a NFC.
The new instructions are: ref_tail_addr, tail_addr and a new attribute [ tail_elems ] for alloc_ref.
For details see docs/SIL.rst
As these new instructions are not generated so far, this is a NFC.
initialization in-place on demand. Initialize parent metadata
references correctly on struct and enum metadata.
Also includes several minor improvements related to relative
pointers that I was using before deciding to simply switch the
parent reference to an absolute reference to get better access
patterns.
Includes a fix since the earlier commit to make enum metadata
writable if they have an unfilled payload size. This didn't show
up on Darwin because "constant" is currently unenforced there in
global data containing relocations.
This patch requires an associated LLDB change which is being
submitted in parallel.
initialization in-place on demand. Initialize parent metadata
references correctly on struct and enum metadata.
Also includes several minor improvements related to relative
pointers that I was using before deciding to simply switch the
parent reference to an absolute reference to get better access
patterns.
This means: handling of alloc_ref [stack].
It can be configured with two new options. See Option/FrontendOptions.td.
As the [stack] attribute is not generated yet, there should be NFC.
Swift SVN r32929
dealloc_ref [destructor] is the existing behavior. It expects the
reference count to have reached zero and the isDeallocating bit to
be set.
The new [constructor] variant first drops the initial strong
reference.
This allows DI to properly free uninitialized instances in
constructors. Previously this would fail with an assertion if the
runtime was built with debugging enabled.
Progress on <rdar://problem/21991742>.
Swift SVN r31142
SILFunctionType of the method instead of its formal type.
Gives more accurate information to the @encoding, makes
foreign error conventions work implicitly, and allows
IRGen's Swift-to-Clang to avoid duplicating arbitrary
amounts of the bridging logic from SILGen.
Some finagling was required in order to avoid calling
getConstantFunctionType from within other kinds of
lowering, which might have re-entered a generic context.
Also required fixing a bug with the type lowering of
optional DynamicSelfTypes where we would end up with
a substituted type in the lowered type.
Also, for some reason, our @encoding for -dealloc
methods was pretending that there was a formal parameter.
There didn't seem to be any justification for this,
and it's not like Clang does that. Fixed.
This commit reapplies r29266 with a conservative build fix
that disables ObjC property descriptors for @objc properties
that lack a getter. That should only be possible in SIL
files, because @objc should force accessors to be synthesized.
Arguably, Sema shouldn't be marking things implicitly @objc
in SIL files, but I'll leave that decision open for now.
Swift SVN r29272
SILFunctionType of the method instead of its formal type.
Gives more accurate information to the @encoding, makes
foreign error conventions work implicitly, and allows
IRGen's Swift-to-Clang to avoid duplicating arbitrary
amounts of the bridging logic from SILGen.
Some finagling was required in order to avoid calling
getConstantFunctionType from within other kinds of
lowering, which might have re-entered a generic context.
Also required fixing a bug with the type lowering of
optional DynamicSelfTypes where we would end up with
a substituted type in the lowered type.
Also, for some reason, our @encoding for -dealloc
methods was pretending that there was a formal parameter.
There didn't seem to be any justification for this,
and it's not like Clang does that. Fixed.
Swift SVN r29266
They don't need storage because they're empty, so we don't emit their offsets, but we still emitted references to their offset variable. Fix this by lowering ref_element_addr to an undef for empty fields.
Swift SVN r23317
