[cfe-dev] [llvmdev] Clang 3.6 and trunk, high RSS usage compared to GCC (12.5GB vs. 0.5GB)

[Ben Pope]

On Tuesday, January 27, 2015 10:19 PM, David Abdurachmanov wrote:
> Hi,
>
> I found that after moving to Clang pre-3.6 (git
> 65d8b4c4998b3a0c20934ea72ede72ef4838a004) and trunk (git
> 718825a8666acd9ceaab70fc7868332f20e2758f) our internal build machines started
> going offline in Jenkins. Clang after 3.5 release is consuming extreme amounts
> of memory in some cases.
>
> I have uploaded [1] one of affected files.
>
> $ g++ -std=c++11 -c -O1 -fPIC vpp_generated.ii -o vpp_generated.o
>
> vmpeak: 582432 KB
> rspeak: 504500 KB = ~ 0.5GB
>
> $ clang++ -std=c++11 -c -O1 -fPIC vpp_generated.ii -o vpp_generated.o
>
> vmpeak: 12992076 KB
> rspeak: 12820184 KB = ~12.5GB
>
> Disabling optimzer (-O0) resolves the issue, and RSS usage drops to ~300MB.
>
> I decided to write here directly instead of creating yet another bug report,
> which usually don't get any feedback/comments.
>
> clang version 3.7.0 (git 718825a8666acd9ceaab70fc7868332f20e2758f)
> Target: x86_64-unknown-linux-gnu
> Thread model: posix
>
> Compiled:
>
> .../configure --prefix=<..> --enable-optimized --with-binutils-include=<..>
> --disable-terminfo --enable-bindings=none CC=gcc CXX=g++ 'CPP=gcc -E'
> 'CXXCPP=g++ -E'

Are you missing --disable-assertions?

Is the problem also apparent on the 3.6 branch or with the 3.6 RC1 build?

Ben