Some work to consummate esil-rs

[ZhangZhuoSJTU]

Todo List

• Correct default size for '[]' and variants opcodes in lexer.rs
• Make sure esil-rs handles internal values in the right way
• Add support for unimplemented opcodes, seeing this issue
• Add support for new opcodes, seeing Sushant's issue and Anton's link
• Never panic
• Add support for unimplemented internal variables: jt, js, ds
• Add support for bit-level change for internal variables.
• If possible, complete vm.rs
• Bug fix in ESP arch (Emmm, which bug? I may need some tests to remind me ;P)
• Support '=[*]' and variants oparators in the right way (which is not an easy work)

[ZhangZhuoSJTU]

Btw, I found esil-rs built a basic assumption about handling internal variables, which is Internal varibables will never be used before EEq/EPoke and after these basic arithmetic operands in ESIL.

For example, following ESIL string will never appear in practice.

1, rax, +, $c63, cf, =

To make sure the validity, @sushant94 would you mind checking this assumption?

[sushant94]

@ZhangZhuoSJTU Imo, the above esil does not make sense. $c is not set by this operation as there is no assignment to rax. If you look at the code for esil emulation (in radare), you'll see the esil_old and esil_cur are only set on assignment to a register.

[ZhangZhuoSJTU]

@sushant94 That's it! I just want to make sure it does work in the correct way. Thanks ;P

[ZhangZhuoSJTU]

This PR is suspended for it is not so urgent and I am working on VSA right now.

[XVilka]

@ZhangZhuoSJTU ping? @kriw @chinmaydd @HMPerson1 please take a look.

[kriw]

I think it would be better to split TODOs into different PRs.

[kriw]

Why not using(define) new enum value (e.g., Token::EPokeDefaultSize) instead of Token::EPoke(USE_DEFAULT_SIZE)

[chinmaydd]

Agree with @kriw here, we can break down issues addressed in this PR into multiple ones.

Maybe we can have Rust enthusiasts contribute for Hacktoberfest? IMO following can be good-first-issue:

• Never panic
• Add support for unimplemented internal variables: jt, js, ds
• Add support for bit-level change for internal variables.

Implementing vm.rs would require design discussions especially if we plan to support features like snapshotting, timeless vm evaluation, etc.

EDIT: Also, I think @ZhangZhuoSJTU is almost done with checkpoint 3 in this PR. If we can clean things up and merge existing work it would be great.

[XVilka]

Ping?

[XVilka]

TODO: Migrate to the https://github.com/radareorg/radeco-lib repository.