[vm/ffi] Most FFI tests broken in ARM_X64

[sjindel-google]

Testing via:

python tools/test.py -n dartkp-android-debug-arm_x64 ffi```

Uncovers at least a dozen crashes.

/cc @mraleph @mkustermann @dcharkes 

[sjindel-google]

This makes the FFI basically unusable on 32-bit devices in Flutter.

[dcharkes]

We haven't implemented simarm at all (#37299). (Edit: bot had simarm in the name.)

[mkustermann]

@sjindel-google Are you sure the changes you made for #38709 are correct?

As mentioned offline some days ago, we should add integration tests to https://github.com/flutter/flutter that can serve as examples as well as actual tests - they would run on all devices go/flutter-dashboard runs on.

[sjindel-google]

We haven't implemented simarm at all (#37299).

This isn't actually about SIMARM at all, it's about cross-compiling from X64 to ARM. The "SIM" part comes from the SIMARM_X64 config, but it's misleading.

Edit: I've changed the way we run the new configuration and updated the OP. There's no "SIM" in the name anymore.

As mentioned offline some days ago, we should add integration tests to https://github.com/flutter/flutter that can serve as examples as well as actual tests - they would run on all devices go/flutter-dashboard runs on.

Does Flutter dashboard run on any 32-bit devices? I can't tell from the dashboard itself.

[sjindel-google]

@sjindel-google Are you sure the changes you made for #38709 are correct?

I'm pretty sure: most of the tests do pass.

[mkustermann]

Seems like this was just a kWordSize vs compiler::target::kWordSize issue.

Does Flutter dashboard run on any 32-bit devices? I can't tell from the dashboard itself.

I would assume so, because the flutter/engine as well as flutter/flutter contain 32-bit vs 64-bit code. It can produce fat apks with 32-bit and 64-bit flutter, so I would assume it's tested. Will follow up on it.

Though my point stands: We should have ffi tests in flutter/flutter to ensure it runs on all devices that normal flutter tests run. Any new configurations / devices flutter adds to their test matrix would immediately test the ffi on new devices / configurations as well.

[sjindel-google]

Seems like this was just a kWordSize vs compiler::target::kWordSize issue.

Most likely, although some tests are still broken after https://dart-review.googlesource.com/c/sdk/+/120260

[sjindel-google]

Actually that was the last of the errors. enable_ffi_test seems broken in both ARM and ARM_X64 configs (it's producing an error from gen_snapshot, but this isn't recognized as a compile-time error).