Beginner's Guide to Linkers (2010) | Hacker News Reader

Beginner's Guide to Linkers (2010)

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229 pointsingve13 comments

Best piece on linkers is in my opinion Ian Lance Taylor's (author of the gold linker) write up[1].

It obviously has been written in a hurry and could need some polish but the content is gold. LWN published an overview with links to the different parts, to make it a little more accessible[2]. I always hoped Ian would turn it into the book he mentioned in the post.

[1] https://www.airs.com/blog/archives/38

[2] https://lwn.net/Articles/276782/

Also, Ulrich Drepper's How To Write Shared Libraries [1] and ELF Handling For Thread-Local Storage [2].

[1] https://www.akkadia.org/drepper/dsohowto.pdf

[2] https://www.akkadia.org/drepper/tls.pdf

Solaris Linkers and Libraries Guide (PDF/html free on Oracle's site) is also an excellent resource - it is Solaris specific, but it's still good for understanding general concepts.

https://docs.oracle.com/cd/E53394_01/pdf/E54813.pdf

Question: Is Linkers & Loaders by John R. Levine still a good book?

Yes. It definitely stands the test of time. It covers several formats (elf, coff, pef, ..., not macho), linker scripts, and explains some old design decisions. You’ll understand object file formats much better, and the fundamental processes of relocation, ... having read Levine. Gold and LLD are (much) faster but they’re still doing the same thing.

And here's Levine's comments FYI https://news.ycombinator.com/threads?id=spamvictim

i found this: https://a3f.at/lists/linkers , to be a slightly more in depth article than this one.

Why does MSVC actually need import libraries? It seems MinGW is able to link against just the .DLL without problems even on Windows.

The DLL API is not stable in the Windows world, only the libraries are stable.

Can you elaborate here? One of the Ls in DLL stands for library after all.

Similar to this, can anyone recommend a good book on linking/loading? I'm mostly looking for something about the process in Linux, but a general reference to common techniques would also be an interesting read. Bonus points if it was published this century.

As mentioned above, Linkers & Loaders by John R. Levine is still a fine book, the Dragon Book of linking. Basically, linking hasn't changed much in 70 years with the minor exception of shared libraries. So I'd recommend that and the Oracle® Solaris 11.3 Linkers and Libraries Guide is 534 pages and gives you an idea of every feature in a fully supported linker. It is ELF specific.

I'd skip gold (ELF specific, GPL) and just study LLD (faster, ELF, COFF, mach-O, BSD). Avoid GNU ld altogether. Adding support to LLD for RISC-V was like a couple of hundred lines of code. Peter Smith has a couple of good talks on LLD.

https://www.youtube.com/watch?v=FiBg0jg4pHk

https://archive.fosdem.org/2019/schedule/event/llvm_lld/

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