I'm afraid this question doesn't make a lot of sense. You seem to be confused about the purpose of the painter tool, or how macros work, probably both.

Neither is painter a sandbox tool, nor do macros have the ability to "run code", arbitrary or otherwise, anywhere.

painter is just a call graph analysis tool for the crates.io ecosystem. It does the analysis based on generated LLVM IR code (which is not "runnable" as is) from all versions of all crates.

It's security application is to reliably find what crate releases are vulnerable if a vulnerability is found in releases of crate Foo.

Note that we already have cargo-audit and advisory-db. painter's goal is to confirm via call graph analysis that "Yes, your crate is vulnerable. This part of your crate calls this vulnerable part of crate Foo".

No crate code is actually run by or in painter, except the code written to run the tool itself, of course ;)

As for Rust macros, they get expanded in the parsing stage after lexing. You can see what's literally expanded with cargo expand. Macros are long gone by the time you get to code generation.

Incidentally, painter has this current limitation listed in the README:

• LTO and optimizers are disabled to prevent inlining, but many cases exist in which the invocation is lost at a bytecode level. Source analysis can improve this. Examples of cases where an invoke is likely lost:
  • Dynamic function calls (pointers, vtables, etc.)
  • Inlining

That's real source/expanded code lost by the time we got to the generated IR code stage. For macros to "run arbitrary code" at that stage would be quite something ;)