[PATCH] D55606: [gn build] Add infrastructure to create symlinks and use it to create lld's symlinks

Wed Dec 12 11:40:53 PST 2018

thakis marked an inline comment as done.
thakis added inline comments.

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Comment at: llvm/utils/gn/build/symlink_or_copy.py:3
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+"""Symlinks, or on Windows copies, an existing file to a second location.
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thakis wrote:
> smeenai wrote:
> > Starting with Windows 10 RS2 (version 1703, released April 2017), you can create symlinks without needing to elevate to administrator if you have developer mode configured. I would imagine that's a reasonably common configuration for LLVM devs, and the symlinks end up saving a bunch of space. Do you think it's worth considering (not necessarily as a part of this patch; it could be done later) attempting to create a symlink even on Windows, and falling back to a copy if you get a permission denied error? I've been meaning to implement something similar on the CMake side.
> I think that'd be great. We probably wouldn't want this for releases (since users might have older Windows versions), but since the gn build is primarily for day-to-day development it makes a lot of sense to me.
> 
> I'd try that in a follow-up so I can test it on my Windows box if that's alright. (Or you could try making the change, it should be a < 10 line change in just this script.)
(ps: Once we no longer need to worry about old Windows versions that don't have symlinks, we can use the LHS on https://github.com/nico/llvm-project-20170507/commit/f24e0f0152d22eecad27f63b58149942c4b9bc22 instead)

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  https://reviews.llvm.org/D55606/new/

https://reviews.llvm.org/D55606