Type annotations for instruction operands are omitted, e.g.
```
%3 = struct $S(%1, %2)
```
Operand types are redundant anyway and were only used for sanity checking in the SIL parser.
But: operand types _are_ printed if the definition of the operand value was not printed yet.
This happens:
* if the block with the definition appears after the block where the operand's instruction is located
* if a block or instruction is printed in isolation, e.g. in a debugger
The old behavior can be restored with `-Xllvm -sil-print-types`.
This option is added to many existing test files which check for operand types in their check-lines.
For address-only types, a temporary was emitted with the same debug variable
and same scope as the instruction it is moved to after entering a shared case,
but it would have a different type, which would create a conflict.
The better way to fix this would probably to use a different scope for both,
but the variable is moved immediately anyway.
It is necessary for opaque values where for casts that will newly start
out as checked_cast_brs and be lowered to checked_cast_addr_brs, since
the latter has the source formal type, IRGen relies on being able to
access it, and there's no way in general to obtain the source formal
type from the source lowered type.
* [SILGenFunction] Don't create redundant nested debug scopes
Instead of emitting:
```
sil_scope 4 { loc "main.swift":6:19 parent 3 }
sil_scope 5 { loc "main.swift":7:3 parent 4 }
sil_scope 6 { loc "main.swift":7:3 parent 5 }
sil_scope 7 { loc "main.swift":7:3 parent 5 }
sil_scope 8 { loc "main.swift":9:5 parent 4 }
```
Emit:
```
sil_scope 4 { loc "main.swift":6:19 parent 3 }
sil_scope 5 { loc "main.swift":7:3 parent 4 }
sil_scope 6 { loc "main.swift":9:5 parent 5 }
```
* [IRGenSIL] Diagnose conflicting shadow copies
If we attempt to store a value with the wrong type into a slot reserved
for a shadow copy, diagnose what went wrong.
* [SILGenPattern] Defer debug description of case variables
Create unique nested debug scopes for a switch, each of its case labels,
and each of its case bodies. This looks like:
```
switch ... { // Enter scope 1.
case ... : // Enter scope 2, nested within scope 1.
<body-1> // Enter scope 3, nested within scope 2.
case ... : // Enter scope 4, nested within scope 1.
<body-2> // Enter scope 5, nested within scope 4.
}
```
Use the new scope structure to defer emitting debug descriptions of case
bindings. Specifically, defer the work until we can nest the scope for a
case body under the scope for a pattern match.
This fixes SR-7973, a problem where it was impossible to inspect a case
binding in lldb when stopped at a case with multiple items.
Previously, we would emit the debug descriptions too early (in the
pattern match), leading to duplicate/conflicting descriptions. The only
reason that the ambiguous description was allowed to compile was because
the debug scopes were nested incorrectly.
rdar://41048339
* Update tests
For those who are unaware, a transformation terminator is a terminator like
switch_enum/checked_cast_br that always dominate their successor blocks. Since
they dominate their successor blocks by design and transform their input into
the args form, we can validate that they obey guaranteed ownership semantics
just like a forwarding instruction.
Beyond removing unnecessary code bloat, this also makes it significantly more
easier to optimize/work with transformation terminators when converting @owned
-> @guaranteed since we do not need to find end_borrow points when the owned
value is consumed.
<rdar://problem/59097063>
SIL type lowering erases DynamicSelfType, so we generate
incorrect code when casting to DynamicSelfType. Fixing this
requires a fair amount of plumbing, but most of the
changes are mechanical.
Note that the textual SIL syntax for casts has changed
slightly; the target type is now a formal type without a '$',
not a SIL type.
Also, the unconditional_checked_cast_value and
checked_cast_value_br instructions now take the _source_
formal type as well, just like the *_addr forms they are
intended to replace.
This is necessary since our func may want to emit conditional code with an early
exit, emitting unused cleanups from the current scope via the function
emitBranchAndCleanups(). If we have not yet created those cleanups, we will
introduce a leak along that path.
rdar://49990484
Specifically, in order to generate runtime errors when we do not handle an enum
appropriately, we form a metatype from the input of the switch. The problem is
that by the time we get to the leaf of the emission tree where this metatype is
created, the input of the switch may have already been consumed. This means
creating the metatype could be a use after free.
This patch fixes the problem by emitting the value_metatype after we emit the
subject of the switch, but before we emit the switch itself.
rdar://49562761
The problem would occur if after we accessed the value, we grew the DenseMap to
insert the value again. But putting in an extra auto I avoid the problem here.
rdar://49609717
Previously we were handling this like we did not have any associated type. This
caused us to break the requirement in [ossa] that all switch_enum successors
associated with payloaded enums must have arguments. We still emit the empty
tuple value (or an undef tuple) if we do not have any associated type.
There was a bug here where we were emitting a shared case if we had arguments.
That is why we needed the hacked in deletion of that block when we emitted
shared blocks. I was able to replace that with an assert to make sure that we do
not regress.
This additionally improved our code generation by eliminating a potential extra
copy when we had such a case. That is where the test updates come from.
Today SILGenPattern maintains the following invariants:
1. All values passed into a switch must be either TakeAlways or BorrowAlways and
loadable input values will be loaded.
2. Loadable types passed to a subtree must be loaded.
3. TakeOnSuccess can only occur with address only types and only in subtrees.
4. A TakeOnSuccess value must go through "fake borrowing"
(i.e. forward/unforwarding) to ensure that along failing cases, we properly
re-enable the cleanup on the aggregate. This means that TakeOnSuccess can
never be handled as a loadable value with ownership enabled and that any
take_on_success value since the original cleanup on the parent value was
disabled must be at +1.
5. We use BorrowAlways instead of TakeOnSuccess for objects to express the
notion that the object is not owned by the sub-tree.
The bug in this tuple code occured at the a place in the code where we go from
an address only parent type to a loadable subtype via TakeOnSuccess. I was
trying to follow (5) and thus I converted the subvalue to use a {load_borrow,
BorrowAlways}. The problem with this is that I lost the cleanup from the tuple
subvalue since take_on_success is just simulating +0 and thus entails having a
cleanup for each of the underlying tuple values.
The fix here was to:
* Create a cleanup for the loadable subvalue leaving it in memory. This address
version of the subvalue we use for the purposes of unforwarding. This avoids
(4).
* load_borrow the subvalue and pass that off to the subtree. This ensures that
we respect (2), (3), (4).
* Unforward in the failure case the in memory subvalue.
This gives us both characteristics as well as in the future the possibility of
enforcing via the ownership verifier that the borrow ends before the
destroy_addr.
I also sprinkled some assertions liberally to maintain invariants.
rdar://47034816
In a previous commit, I banned in the verifier any SILValue from producing
ValueOwnershipKind::Any in preparation for this.
This change arises out of discussions in between John, Andy, and I around
ValueOwnershipKind::Trivial. The specific realization was that this ownership
kind was an unnecessary conflation of the a type system idea (triviality) with
an ownership idea (@any, an ownership kind that is compatible with any other
ownership kind at value merge points and can only create). This caused the
ownership model to have to contort to handle the non-payloaded or trivial cases
of non-trivial enums. This is unnecessary if we just eliminate the any case and
in the verifier separately verify that trivial => @any (notice that we do not
verify that @any => trivial).
NOTE: This is technically an NFC intended change since I am just replacing
Trivial with Any. That is why if you look at the tests you will see that I
actually did not need to update anything except removing some @trivial ownership
since @any ownership is represented without writing @any in the parsed sil.
rdar://46294760
This commit allows the initial switch subject value to be emitted at +0 if we
can emit it that way. As you can imagine since we have +0 normal function
arguments this should tighten up a lot of code around switches on arguments. So
I got to delete a bunch of code in the tests. = ).
Some things to note:
1. If the switch is given a +1 value, we will still try to let it through at +1
until we hit a part of the decision tree where previously we would need to use
TakeOnSuccess. This means that +1 values that go through irrefutable patterns
like tuple splitting should still be emitted at +1.
2. If we are returned an address only type without a cleanup, we copy it and
pass it down at +1 like the old code.
3. I also elided the last ownership check in SILGenPattern in this commit. After
this, there is only 1 specialization for ownership in the swift compiler that is
in Apply emission. Thats my next target.
rdar://29791263
The problem here was that if we had a tuple with mixed address only and loadable
components and we used take on success during pattern matching, we would load
the loadable component with a load [take] and then pass it as take on success.
Instead we load the loadable components of the tuple using a load_borrow and
make the cast consumption kind BorrowAlways.
This can not happen with enum element emission since enum element emission does
not support take_on_success so the problem can not occur there.
SR-9029
rdar://45345844
This is the enum element analogue of the tuple fixup in:
359eda52e5. Additionally as a nice fixup I can now
enable ownership verification on most of the switch code.
I ran into commit ordering issues with cleaning up the address only part of the
emitEnumElement so I included it in this commit. Specifically this was because I
realized that it was possible to get a copy_on_success with an object from this
code and I wanted to enforce the invariant that ConsumptionManagedValues only
have copy_on_success with addresses and borrow_always with objects. It was less
convoluted to just fix the address only code to fit that formulation rather than
shoe-horn the old code into the new form.
rdar://29791263
To do this the commit does a few things:
1. If we enter the tuple dispatch code with an address that is loadable, we
always immediately perform a load_borrow and change the consumable managed value
to BorrowAlways.
2. If we have a take_on_success object, we immediately borrow. We do not want to
do with TakeOnSuccess since we want to define away the need to unforward since
unforwarding recreates a destroy on the already invalidated parent tuple object.
Notice that this code still handles TakeAlways so in simple cases where we have
a +1 value, everything still works.
Since emitTupleDispatchWithOwnership now handles only objects, I renamed it to
emitTupleObjectDispatch.
rdar://29791263
This does not eliminate the entrypoints on SILBuilder yet. I want to do this in
two parts so that it is functionally easier to disentangle changing the APIs
above SILBuilder and changing the underlying instruction itself.
rdar://33440767
This is how we originally controlled whether or not we printed out ownership
annotations when we printed SIL. Since then, I have changed (a few months ago I
believe) the ownership model eliminator to know how to eliminate these
annotations from the SIL itself. So this hack can be removed.
As an additional benefit, this will let me rename -enable-sil-ownership to
-enable-sil-ownership-verifier. This will I hope eliminate confusion around this
option in the short term while I am preparing to work on semantic sil again.
rdar://42509812
The SILGen testsuite consists of valid Swift code covering most language
features. We use these tests to verify that no unknown nodes are in the
file's libSyntax tree. That way we will (hopefully) catch any future
changes or additions to the language which are not implemented in
libSyntax.
I am going to leave in the infrastructure around this just in case. But there is
no reason to keep this in the tests themselves. I can always just revert this
and I don't think merge conflicts are likely due to previous work I did around
the tooling for this.
Otherwise, the plus_zero_* tests will have plus_zero_* as a module name, causing
massive FileCheck problems.
The reason why I am doing it with the main tests is so that I can use it when
syncing branches/etc.
radar://34222540
