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.
Static initializers are now represented by a list of literal and aggregate instructions in a SILGlobalVariable.
For details see SIL.rst.
This representation is cleaner than what we did so far (point to the initializer function and do some pattern matching).
One implication of that change is that now (a subset of) instructions not necessarily have a parent function.
Regarding the generated code it's a NFC.
Also the swift module format didn't change because so far we don't serializer global variables.
We compile with a pedantic warning that complains about these things,
and the massive flood of warnings is actually causing problems for the
build infrastructure.
This is the first in a series of commits that cleans up the SILOwnershipVerifier
based off of discussions/feedback with other people who are now using it. The
next step is to split the checker from the declarative computation of what I
call the UseOwnershipRequirement.
rdar://33358110
Otherwise, one can run into situations where an Any from a SILUndef results in
SSA values having destroying uses. Since we are dealing with an undef value,
from an ownership perspective, we can assume any form of ownership constraints
that we want. Thus we can treat the value as being eternal and thus from the
ownership verifier's perspective like a metatype.
rdar://33358110
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".
This semantic attribute allows a user to disable ownership verification on
specific functions.
The intention is that once I turn on the sil ownership verifier for parts of the
stdlib, if an engineer exposes an ownership issue, they can disable ownership
verification on that specific function, file a bug, and continue with their
work.
rdar://31880847
This means that a trivial enum case of a non-trivial enum can be returned @owned
even though it is trivial. We already follow this pattern with bb arguments.
rdar://31880847
This is needed to ensure that SILGenPattern propagates values at +0 instead of
+1.
I also improved our handling of terminators in general when it comes to having
"borrowed" arguments. The basic verification requirement is that the
end_borrow_argument is treated as a use of the parent borrow. This ensures that
the borrowed argument can not extend the lifetime of the borrowed value without
the verifier triggering.
rdar://31880847
Use 'hasAssociatedValues' instead of computing and discarding the
interface type of an enum element decl. This change has specifically not
been made in conditions that use the presence or absence of the
interface type, only conditions that depend on the presence or absence
of associated values in the enum element decl.
Having such a builtin makes it easier for the optimizer to reason about what is actually happening.
I plan to add later some optimizations which can optimize pieces of code dominated by such a check.
I put in a simple fixup pass (MarkUninitializedFixup) for staging purposes. I
don't expect it to be in tree long. I just did not feel comfortable fixing up in
1 commit all of the passes up to DI.
rdar://31521023
Today the ownership checker has two different behaviors on detecting an error:
1. In normal operating mode, it prints a message to stderr and asserts.
2. In testing mode, it prints a message to stderr and returns false.
This refactoring will allow me to add a third mode:
1. In optimization mode, it does not print a message and just returns false.
This will allow me to use the verifier in an early ARC optimization that I need
to prevent COW copies due to refactoring in SILGenPattern.
rdar://29870610
Introduce a new runtime entry point,
`swift_objc_swift3ImplicitObjCEntrypoint`, which is called from any
Objective-C method that was generated due to `@objc` inference rules
that were removed by SE-0160. Aside from being a central place where
users can set a breakpoint to catch when this occurs, this operation
provides logging capabilities that can be enabled by setting the
environment variable SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT:
SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT=0 (default): do not log
SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT=1: log failed messages
SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT=2: log failed messages with
backtrace
SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT=3: log failed messages with
backtrace and abort the process.
The log messages look something like:
***Swift runtime: entrypoint -[t.MyClass foo] generated by
implicit @objc inference is deprecated and will be removed in
Swift 4
Previously often times when casting a value, we would just pass along the
cleanup of the uncasted value. With semantic SIL this is no longer correct since
the cleanup now needs to be on the cast result.
This caused problems for certain usages of Builtin.castToNativeObject(...) by
the stdlib. Specifically, the stdlib was using this on AnyObject values that
were not necessarily native. Since we were recreating the cleanup on the native
value, a swift native release was being used =><=.
In this commit I solve this problem by:
1. Adding an assert in Builtin.castToNativeObject(...) that ensures that any value
passed to Builtin.castToNativeObject() is known conservatively to use swift
native reference counting.
2. I changed all uses where we do not have a precondition of a native ref
counting type to use Builtin.castToUnknownObject(...).
3. I added a new Builtin called Builtin.unsafeCastToNativeObject(...) that does
not have the compile time check. I used this to rewrite callsites in the stdlib
where we know via preconditions that an AnyObject will dynamically always be
native.
rdar://29791263
...and IRGen it into a call to __tsan_write1 in compiler-rt. This is
preparatory work for a later patch that will add an experimental
option to treat Swift inout accesses as TSan writes.
