Stream: general

Topic: ✔ Aarch64: does cranelift split function into multiple?

Adel Prokurov (Feb 13 2022 at 15:56):

So for example this: <https://gist.github.com/playXE/bcadfaefeecaf511d81f4b141ca1e1bc>. There is relatively large Cranelift IR dump but when I look at disassembly it seems that it just splits function into a few and other parts I can't see

bjorn3 (Feb 13 2022 at 22:05):

Cranelift can't split functions into multiple parts. I think whatever you used for disassembling returned an incomplete disassembly. It likely chokes on the constant embedded inside the instruction stream. At address 0x1478140d0 there should be a 64 bit constant followed by the rest of the code. The branch instruction at the end of the disassembly jumps over this constant.

bjorn3 (Feb 13 2022 at 22:05):

@Adel Prokurov ^

Adel Prokurov (Feb 14 2022 at 09:06):

bjorn3 said:

Cranelift can't split functions into multiple parts. I think whatever you used for disassembling returned an incomplete disassembly. It likely chokes on the constant embedded inside the instruction stream. At address 0x1478140d0 there should be a 64 bit constant followed by the rest of the code. The branch instruction at the end of the disassembly jumps over this constant.

Thanks for the reply. I'll look into alternative disassembler then (I am using capstone at the moment)

Adel Prokurov (Feb 14 2022 at 09:13):

So I tried to use bad64 to disarm arm64 code and it works just fine. Probably capstone just does not work correctly for M1?

Notification Bot (Feb 14 2022 at 09:13):

Adel Prokurov has marked this topic as resolved.

bjorn3 (Feb 14 2022 at 11:09):

For capstone you will have to explicitly enable the skipdata option. Cranelift uses also capstone for debugging: https://github.com/bytecodealliance/wasmtime/blob/05ace6c0e24f4fd8e256edab7de841a5b28c5735/cranelift/src/disasm.rs#L96

Adel Prokurov (Feb 15 2022 at 07:36):

bjorn3 said:

For capstone you will have to explicitly enable the skipdata option. Cranelift uses also capstone for debugging: https://github.com/bytecodealliance/wasmtime/blob/05ace6c0e24f4fd8e256edab7de841a5b28c5735/cranelift/src/disasm.rs#L96

I didn't know that! Thanks for help

Last updated: Dec 23 2024 at 13:07 UTC