LLVM/Clang 3.7 Debian package build size

[Faheem Mitha]

Hi,

I just tried backporting LLVM/Clang 3.7 from Debian unstable to 
stable/jessie. The build ran out of space after consuming approximately 32 
GB.

faheem at orwell:/usr/local/src/clang-3.7/llvm-toolchain-3.7-3.7$ du -hs
32G

I asked on #llvm on OFTC, and was told the build size should not exceed 17 
GB or so. See the conversation below.

Can anyone tell me how much space is needed, and if there is some way
to reduce the build size and/or time?

                                                 Regards, Faheem Mitha

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11:24 <faheem> Hello. Approximately how much space is needed to build
LLVM/Clang 3.7, please? I see my build took 32 GB (according to du) and it
crashed as out of space.
11:26 <echristo_> faheem: a debug build on my linux box took:
11:26 <echristo_> dzur:~/builds/build-llvm> du -s .
11:26 <echristo_> 12884756	.
11:27 <echristo_> or if you want that in human readable:
11:27 <echristo_> dzur:~/builds/build-llvm> du -sh .
11:27 <echristo_> 13G	.
11:29 <faheem> echristo_: Strange. I wonder why mine took 32 GB then.
11:29 <faheem>faheem at orwell:/usr/local/src/clang-3.7/llvm-toolchain-3.7-3.7$ du -hs
11:29 <faheem> 32G
11:29 <echristo_> probably shouldn’t build in the source directory.
11:30 <echristo_> also keep in mind that yours includes sources and
everything if you did.
11:30 <faheem> echristo_: Well, I'm just rebuilding the Debian package.
Not my own work.
11:30 <faheem> echristo_: Ok, in that case, how much space would be
required?
11:33 <echristo_> dzur:~/sources/llvm> du -sh .
11:33 <echristo_> 4.2G	.
11:33 <echristo_> including all of the git stuff.
11:33 <echristo_> so including git just over 17G
11:33 <echristo_> and the testsuites.
11:37 <faheem> echristo_: Oh. I wonder what I'm doing wrong here, then.
Since I'm getting  32 GB.
11:38 <echristo_> no idea. what are you doing? :)
11:39 <faheem> echristo_: Just rebuilding the Debian package.
11:39 <echristo_> not sure what it’s doing. I’m just doing a normal
build of llvm.
11:39 <faheem> After I clean it, it's 355M. So most of it is the build.
11:39 <faheem> echristo_: Oh. Well, I guess I'll need to talk to the
packagers then. I was hoping it was something obvious.
11:40 <echristo_> *nod* you could try checkout out the sources and
building that and see if your numbers are greatly different from me :)
11:41 <faheem> echristo_: Fair enough. Thank you.
11:41 <echristo_> any time :)