Dart 3.5.4 Wrong Offset

[lorenzodifuccia]

Hello,
I'm running reflutter == 0.8.2 on a iOS app with Dart 3.5.4 - Snapshot: 80a49c7111088100a233b2ae788e1f48
Using the --patch-dump argument, reFlutter generate the dump.dart, however every offset is set to 0x0000000000000080:

What can I modify in a custom engine build in order to change the offset to absolute?
Thank you <3

[lorenzodifuccia]

The problem is related to that specific Dart VM, also Android with same snapshot gave me the same behaviour:

Just for reference, blutter outputs correct offsets, but I know it has a different approach.

[jayluxferro]

The 0x80 offset issue is known for certain Flutter versions. The problem is in patch_source() in utils.py: for Flutter 3.24.0 (Dart 3.5.4, hash 80a49c7...), the instructions_table_.rodata()->entries()[...]pc_offset approach returns a fixed struct field offset instead of the actual code entry point for every function.

The medium.com article referenced in #277 describes the same approach that's already implemented for ver > 38, but it doesn't work correctly for 3.24.0 specifically. This needs investigation of the Flutter engine's InstructionsTable struct layout for this version.

Workaround: If you can identify a nearby Flutter version where offsets work, rebuild the engine for that version instead.