Lensm, a tool for viewing disassembly (opens in new tab)

(storj.io)

156 pointsjtolds2y ago17 comments

17 comments

Wow, having to stare at disassembly too often, I really like this.

Makes it much faster to follow branches and can easily see what instructions correspond to source code lines, even though it's not very exact at higher optimization levels.

This should be integrated in all IDEs.

mananaysiempre2y ago

With recent versions of GNU objdump, you can use --source --visualize-jumps=color and perhaps also --reloc or --dynamic-reloc for a similar experience with the native toolchain. (Unfortunately, -S/--source absolutely sucks for executables compiled at -O2.)

Other tricks include --no-addresses --no-show-raw-insn, which make the disassembly decently diffable.

beeburrt2y ago

Nice. Thanks for the tip

PhilipRoman2y ago

If you don't care about source lines, I find radare2 has a really good disassembler (in graph mode)

It's meant for reverse engineering but I use it for debugging purposes too

c7DJTLrn2y ago

It would probably be worth mentioning that this is for Go in the title.

jcul2y ago

I'd imagine it would work for any binary with debug symbols, even though the tool is written in go?

Though I haven't tried it, on mobile right now.

liamwire2y ago

I’m not so sure. From the article, the author mentions that they’re using an internal library from the Go compiler for the disassembly.

egonelbre2y ago

Yeah, at the moment, unfortunately only works for Go.

But implementing a different backend (e.g. llvm-symbolizer, objdump etc.) shouldn't be too difficult. The main things it needs to do are 1. list the decompilable symbols in the file, 2. disassemble and pull in the relevant source code.

The UI part doesn't care whether it's Go or not.

vzaliva2y ago

I tried it with C and it does not work. So I guess it is go-specific indeed.

2 more replies

Conscat2y ago

Can it demangle non-Go identifiers?

brancz2y ago

Love lensm! I've used it on several occasions to teach people about inlining, bounds check removals, and other performance related topics that are best highlighted by actually seeing differences in assembly. I find it's easier for people to understand what is actually happening under the hood than just tell them "do this and it's faster".

I also highly recommend following the creator. I'm always impressed with anything Egon creates.

throwaway293032y ago

Previous threads about lensm

https://news.ycombinator.com/item?id=32138111 - Lensm, a Tool for Viewing Disassembly (2022)

https://news.ycombinator.com/item?id=32133394 - Lensm: Go Assembly and Source Viewer (2022)

djmips2y ago

I like the name, it reminds me of Lensman - the classic sci-fi series that inspired the first video game Spacewar!

speps2y ago

Looks a lot like the P4Merge diffing window: https://www.perforce.com/manuals/p4merge/Content/P4Merge/dif...

fitz-re2y ago

This would be great for reversing tools such as IDA and Binary Ninja!

j / k navigate · click thread line to collapse