Add `rust objdump` or `rust dis` for dissecting / disassembling generated libraries

[pnkfelix]

We may or may not already have objdump like facilities available, but I do not see them in the help text for rust.

There is a small inspection facility in rustc: rustc --ls <library-crate>. This just scratches the surface of what I might want to see, though.

I also see rustc::metadata::creader::dump_crates, but I do not think that is a real disassembler either.

[emberian]

@pnkfelix what exactly do you want to see? why should it be integrated into rust rather than using external tools?

[pnkfelix]

@cmr Sure, what I really want is some documented facility for inspecting a compiled crate: disassembling it and displaying its meta-data.

I want to be able to dissect a compiled library as a way to understand the code rustc is generating, and in my experience, a good disassembler will include not only the decoded instruction stream, but also render structures (stored in a constant pool or similar meta-data) referenced by embedded addresses in the instruction stream.

The standard objdump and debug-info inspection facilities may get us part of the way to this goal, but I have been assuming that it would be better for us to provide our own tools for inspecting the meta-data we generate, rather than coupling our meta-data format [to some tool we do not maintain/control].

I phrased my request in terms of an addition to rust because when I inspected the output from rust's help message, it appears to provide access to all of the other installed tools:

• rustc : rust build,
• rustdoc : rust doc,
• rusti : rust sketch, and
• rustpkg : rust pkg,

so I was assuming that any tool we provide would also be accessible via rust.

[emberian]

Ok, sure. Thanks!

This would likely be implemented on top of LLVM's MC project.

[catamorphism]

Triage bump.

[nham]

Triage bump.

[steveklabnik]

I'm pulling a massive triage effort to get us ready for 1.0. As part of this, I'm moving stuff that's wishlist-like to the RFCs repo, as that's where major new things should get discussed/prioritized.

This issue has been moved to the RFCs repo: rust-lang/rfcs#652