@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
Use `unsigned` instead of `bool` for the member to make all members of
the structure the same. This fixes the behaviour of the structure on
Windows. The difference in the type caused the bitfields to be pushed
to the natural alignment of int resulting in the structure being padded
to 12-bytes instead of being packed into 4. Using `#pragma pack` also
did not make a difference here as the structure remained padded to
12-bytes.
* 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.
* Implement a few silcombine transformations for arrays
- Useless existential_ref <-> class conversions.
- mark_dependence_inst depending on uninteresting instructions.
- release(init_existential_ref(x)) -> release(x) when hasOneUse(x)
- Update COWArrayOpt to handle the new forms generated by this.
these aren't massive performance wins, but do shrink the size of SIL when
dealing with arrays.
* Generalize testcase to work on linux and on mac when checking stdlib is enabled.
Refactor UnaryInstructionWithTypeDependentOperandsBase into two template
classes, where the original template now subclasses a simpler template
called "InstructionBaseWithTrailingObjects".
