We should pass foreign references as Direct_Unowned calling convention,
this happened for non-const pointers. Unfortunately, we passed the const
variants as Indirect_In. This resulted in SILGen trying to insert a
non-sensical conversion. This triggered an assertion failure or a
miscompilation depending on how the compiler was compiled.
rdar://149398905
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.
- #58975 switched many tests from XFAIL on linux to linux-gnu, so seven
fail on the Android CI and two natively. They are now explicitly excluded.
- #39605 added several C++ Interop tests, 11 of which fail on the Android CI,
so disable them for now.
- #42478 removed the @noescape attribute for the non-Android
SIL/clang-function-types tests, so I remove it for Android too.
- My pull #40779 moved the Swift pointer tags to the second byte, so
SILOptimizer/concat_string_literals.64 will need to be updated for that,
disabled it for now.
- Compiler-rt moved the directory in which it places those libraries for
Android, llvm/llvm-project@a68ccba, so lit.cfg is updated for that.
There are three major changes here:
1. The addition of "SILFunctionTypeRepresentation::CXXMethod".
2. C++ methods are imported with their members *last*. Then the arguments are switched when emitting the IR for an application of the function.
3. Clang decls are now marked as foreign witnesses.
These are all steps towards being able to have C++ protocol conformance.
