Now that we have generalized existentials in Embedded Swift, we also
have all of the infrastructure for metatypes. They're lazily
constructed on an as-needed basis, but otherwise work the same way as
in non-Embedded Swift.
Fixes rdar://145706221.
Support for existentials in Embedded Swift has been available for a
little while now and appears to be solid. Remove the ability to disable
them (via `-disable-experimental-feature EmbeddedExistentials`), both
because it simplifies the code and because it's an ABI break to
disable the feature.
**Explanation**: We would like untyped throws to be available in Embedded Swift when system allocator is available.
**Scope**: limited to Embedded Swift.
**Risk**: low due to isolated scope, additive nature of the change, and no adoption of untyped throws in Embedded Swift so far.
**Testing**: added new lit tests.
**Issue**: rdar://171325402
If value-type deinits cannot be de-virtualized we now print a more useful error message, including call tree information, source location and the type of the struct containing the deinit.
Although this situation should never happen, it's still good to have this error message - just in case.
Diagnostics only work with `SourceLoc` which is basically a pointer into a buffer of the loaded source file.
But when debug info is de-serialized, the SIL `Location` consists of a filename+line+column.
To "convert" this to a `SourceLoc`, the file must be loaded.
This change adds `DiagnosticEngine.getLocationFromExternalSource` for this purpose.
Also, the new protocol `ProvidingSourceLocation` - to which `SourceLoc` and `Location` conform - help to generalize the helper struct `Diagnostic` and make this "conversion" happen automatically.
1. move embedded diagnostics out of the PerformanceDiagnostics pass. It was completely separated from the other logic in this pass, anyway.
2. rewrite it in swift
3. fix several bugs, that means: missed diagnostics, which led to IRGen crashes
* look at all methods in witness tables, including base protocols and associated conformances
* visit all functions in the call tree, including generic functions with class bound generic arguments
* handle all instructions, e.g. concurrency builtins
4. improve error messages by adding meaningful call-site information. For example:
* if the error is in a specialized function, report where the generic function is originally specialized with concrete types
* if the error is in a protocol witness method, report where the existential is created
Doug Gregor
Max Desiatov
Erik Eckstein
Arnold Schwaighofer
Daniil Kovalev