We can't make the same assumptions about .sib files.
Ideally, we should serialize the module's stage and set WasDeserializedCanonical
based on that state. However, we probably still want the IsSIB flag for
assertions.
We need to be able to detect function definitions that have been
deserialized. There's no need to rerun diagnostics on those functions,
and in some cases it's actually incorrect to do so. With exclusivity,
we could even miscompile in theory (debug assert) because the fully
optimized SIL does adhere to rules requires by the
diagnostic. Hopefully that specific issue can be fixed soon, but the
point is that we need control over the order that passes are run
because we play these games all the time. Not to mention the wasted
compilation time.
It would probably be sufficient to check isAvailableExternally. However, using
an explicit flag is, well, more explicit. It also generalizes to serializing IR
at any stage.
Note: I would strongly prefer not to rely on this flag for correctness. In
principle, serialized SIL should be compatible with all SIL stages prior to the
serialization point. However, it is necessary to fix bugs in the short term, and
useful for bootstrapping SIL changes in general. Also, it formalizes some
assumptions about the way the pass pipeline is expected to work making it easier
to reason about and avoid pass ordering bugs. In particular, we should not be
relying on a second round of the mandatory pass pipeline to catch important
performance opportunities.
@noescape function types will eventually be trivial. A
convert_escape_to_noescape instruction does not take ownership of its
operand. It is a projection to the trivial value carried by the closure
-- both context and implementation function viewed as a trivial value.
A safe SIL program must ensure that the object that the project value is based
on is live beyond the last use of the trivial value. This will be
achieve by means of making the lifetimes dependent.
For example:
%e = partial_apply [callee_guaranteed] %f(%z) : $@convention(thin) (Builtin.Int64) -> ()
%n = convert_escape_to_noescape %e : $@callee_guaranteed () -> () to $@noescape @callee_guaranteed () -> ()
%n2 = mark_dependence %n : $@noescape @callee_guaranteed () -> () on %e : $@callee_guaranteed () -> ()
%f2 = function_ref @use : $@convention(thin) (@noescape @callee_guaranteed () -> ()) -> ()
apply %f2(%n2) : $@convention(thin) (@noescape @callee_guaranteed () -> ()) -> ()
release_value %e : $@callee_guaranteed () -> ()
Note: This is not yet actually used.
Part of:
SR-5441
rdar://36116691
- Clear the 'serialized' flag on witness tables and vtables
after serialization, not just functions. This fixes SIL
verifier failures if post-serialization SIL is printed
out and parsed back in.
- Clear the 'serialized' flag when deserializing functions,
witness tables and vtables in a module that has already
been serialized. This fixes SIL verifier failures if
we deserialize more declarations after serializing SIL.
We were seeing SIL verifier failures on bots that run the
tests with the stdlib built with non-standard flags.
Unfortunately I don't have a reduced test case that would
fail in PR testing without these fixes.
Fixes <rdar://problem/36682929>.
Consider a module with two files, one of which references a
function in the other file. If the function had PublicNonABI
linkage, the forward reference has HiddenExternal linkage.
If we saw the forward reference first in the merge modules
process, we would not update the linkage of the function
when we later deserialized its body.
This would result in it being dropped from the final merged
SIL module. Previously this did not cause any problems
because all inlineable functions had public linkage, but now
that default argument generators no longer have public entry
points, this could cause linker errors.
For the majority of artificial helper functions the filename is
actively misleading since it usually represents the file of the caller
that triggered the helper to be generated. Instead, this patch creates
a virtual filname `<compiler-generated>` to make it very obvious that
the function has not correspondence to any source code.
<rdar://problem/33809560>
This is going to be used for "always emit into client" functions,
such as default argument generators and stored property
initializers.
- In dead function elimination, these functions behave identically to
public functions, serving as "anchors" for the mark-and-sweep
analysis.
- There is no external variant of this linkage, because external
declarations can use HiddenExternal linkage -- the definition should
always be emitted by another translation unit in the same Swift
module.
- When deserialized, they receive shared linkage, because we want the
linker to coalesce multiple copies of the same deserialized
definition if it was deserialized from multiple translation units
in the same Swift module.
- When IRGen emits a definition with this linkage, it receives the
same LLVM-level linkage as a hidden definition, ensuring it does not
have a public entry point.
* Reduce array abstraction on apple platforms dealing with literals
Part of the ongoing quest to reduce swift array literal abstraction
penalties: make the SIL optimizer able to eliminate bridging overhead
when dealing with array literals.
Introduce a new classify_bridge_object SIL instruction to handle the
logic of extracting platform specific bits from a Builtin.BridgeObject
value that indicate whether it contains a ObjC tagged pointer object,
or a normal ObjC object. This allows the SIL optimizer to eliminate
these, which allows constant folding a ton of code. On the example
added to test/SILOptimizer/static_arrays.swift, this results in 4x
less SIL code, and also leads to a lot more commonality between linux
and apple platform codegen when passing an array literal.
This also introduces a couple of SIL combines for patterns that occur
in the array literal passing case.
For now these are underscored attributes, i.e. compiler internal attributes:
@_optimize(speed)
@_optimize(size)
@_optimize(none)
Those attributes override the command-line specified optimization mode for a specific function.
The @_optimize(none) attribute is equivalent to the already existing @_semantics("optimize.sil.never") attribute
Except GenericEnvironment.h, because you can't meaningfully use a
GenericEnvironment without its signature. Lots less depends on
GenericSignature.h now. NFC
This replaces the '[volatile]' flag. Now, class_method and
super_method are only used for vtable dispatch.
The witness_method instruction is still overloaded for use
with both ObjC protocol requirements and Swift protocol
requirements; the next step is to make it only mean the
latter, also using objc_method for ObjC protocol calls.
introduce a common superclass, SILNode.
This is in preparation for allowing instructions to have multiple
results. It is also a somewhat more elegant representation for
instructions that have zero results. Instructions that are known
to have exactly one result inherit from a class, SingleValueInstruction,
that subclasses both ValueBase and SILInstruction. Some care must be
taken when working with SILNode pointers and testing for equality;
please see the comment on SILNode for more information.
A number of SIL passes needed to be updated in order to handle this
new distinction between SIL values and SIL instructions.
Note that the SIL parser is now stricter about not trying to assign
a result value from an instruction (like 'return' or 'strong_retain')
that does not produce any.
Previously we stored this inside each default argument
initializer context. This was overkill, because it is
the same for all default arguments in a single function,
and also insufficient, because initializer contexts are
not serialized and thus not available in SILGen when
the function is in a different module.
Instead store it directly inside the function and
serialize it.
NFC for now, since SILGen isn't using this yet.
This commit contains:
-) adding the new instructions + infrastructure, like parsing, printing, etc.
-) support in IRGen to generate global object-variables (i.e. "heap" objects) which are statically initialized in the data section.
-) IRGen for global_value which lazily initializes the object header and returns a reference to the object.
For details see the documentation of the new instructions in SIL.rst.
Remove the cast consumption kind from all unconditional casts. It
doesn't make sense for unconditional casts, complicates SIL ownership,
and wasn't fully supported for all variants. Copies should be
explicit.
Consider a class hierarchy like the following:
class Base {
func m1() {}
func m2() {}
}
class Derived : Base {
override func m2() {}
func m3() {}
}
The SIL vtable for 'Derived' now records that the entry for m1
is inherited, the entry for m2 is an override, and the entry
for m3 is a new entry:
sil_vtable Derived {
#Base.m1!1: (Base) -> () -> () : _T01a4BaseC2m1yyF [inherited]
#Base.m2!1: (Base) -> () -> () : _T01a7DerivedC2m2yyF [override]
#Derived.m3!1: (Derived) -> () -> () : _T01a7DerivedC2m3yyF
}
This additional information will allow IRGen to emit the vtable
for Derived resiliently, without referencing the symbol for
the inherited method m1() directly.
This has the same semantics as open_existential_box, but returns an object value
instead of an address.
This is used in SIL opaque values mode. Attempting to reuse open_existential_box
in this mode causes SIL type inconsistencies that are too difficult to work
around. Adding this instruction allows for consistent handling of opaque values.
The original versions of several of these currently redundant instructions will
be removed once the SIL representation stabilizes.
These instructions have the same semantics as the *ExistentialAddr instructions
but operate directly on the existential value, not its address.
This is in preparation for adding ExistentialBoxValue instructions.
The previous name would cause impossible confusion with "opaque existentials"
and "opaque existential boxes".
Till now createApply, createTryApply, createPartialApply were taking some arguments like SubstCalleeType or ResultType. But these arguments are redundant and can be easily derived from other arguments of these functions. There is no need to put the burden of their computation on the clients of these APIs.
The removal of these redundant parameters simplifies the APIs and reduces the possibility of providing mismatched types by clients, which often happened in the past.
All we need to store is whether the SILDeclRef directly
references the declaration, or if it references a curry
thunk, and we already have an isCurried bit for that.
