cmd/objdump: implement arm64 disassembler

[randall77]

No description provided.

[bradfitz]

I see that ARM released machine-readable architecture specs:

https://alastairreid.github.io/alastairreid.github.io/ARM-v8a-xml-release/

/cc @rsc @cherrymui

[bradfitz]

/cc @williamweixiao

[bradfitz]

@williamweixiao, is this happening for Go 1.9? It's looking pretty late, unless the work is already done and non-invasive to other ports.

[williamweixiao]

@bradfitz I submitted the patch (https://go-review.googlesource.com/c/43651/) three weeks ago but still get no feedback. The patch is non-invasive to other ports and parts at all.

[cherrymui]

A CL is submitted for x/arch. We can review and submit the CL to x/arch during the freeze. I don't think this will be in Go 1.9.

[bradfitz]

@cherrymui, I'm fine with this as a late addition if you can review these CLs. I'm a little sad we've let this sit so long.

I'm okay with it as a late addition because it's well isolated from everything else. There's very little risk.

[bradfitz]

@randall77, maybe you can help review too?

[cherrymui]

I thought it probably includes some new instructions (in CL https://go-review.googlesource.com/c/41654/) which will not go into Go 1.9, so this as well. But I may be wrong.

[williamweixiao]

@cherrymui yes, it supports almost all armv8 instructions and is fully tested by comparing to GNU objdump output. As for Go syntax part, the basic instructions (include FP) are fully tested with assembler as inputs and we will add these tests into assembler soon. The only untested part is for the new instructions added by CL41654 since it has not been merged. But we'd like to keep this part and submit bug fixing patch if needed in the future because the decoder table is automatically generated by tool and it's hard to isolate new instructions.

[williamweixiao]

The issue can be closed since the patch (CL 43651) has been merged.

[bradfitz]

@williamweixiao, let's keep this open until it's vendored into std for Go 1.10.

[williamweixiao]

When will it be vendored into go repo?
I need to submit another patch to "cmd/internal/objfile" for enabling arm64 disassembler to be used by other tools such as objdump and pprof.

[bradfitz]

@williamweixiao, there is no automatic process that vendors this into the main go repo. It requires a human to do that manually, and it's nobody's job. It is done when needed, by whoever needs it. Feel free to send a change.

[gopherbot]

CL https://golang.org/cl/49530 mentions this issue.

[gopherbot]

Change https://golang.org/cl/58930 mentions this issue: cmd/internal/objfile: add arm64 disassembler support