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Author Topic: Scribus-git doesn't start when compiled with flto ( segmentation fault on start)  (Read 400 times)

Brane212

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Hi all.

I am trying to install Scribus on my Gentoo setup. I've notice significant speedup with all complex packages, when I compile them with -flto, so i trid to use that on Scribus.
With LTO ( latest gcc - 7.2), it compiles and installs fine, but it croaks on start. With non-LTO, it compiles and runs fine.

I tried to run it through ld-linux.so and it seems that it dies during dyring dynamic linking phase.

Code: [Select]

LD_DEBUG=all /lib/ld-linux-x86-64.so.2 $(which scribus)


gets me:

...
Quote

         30426:     symbol=_ZN7QString16fromAscii_helperEPKci;  lookup in file=/usr/lib64/libQt5Core.so.5


         30426:     binding file /usr/bin/scribus

        to /usr/lib64/libQt5Core.so.5
        : normal symbol `_ZN7QString16fromAscii_helperEPKci' [Qt_5]

Has anyone tried t compile it with -flto ?

Brane212

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Just to clarify: I'm not whining.

Just asking - should Scribus work with LTO optimisations ( and the error is elshwere - possibly within QtCore) or is the probably cause a fault within Scribus sources.

If anyone is interested, here are my FLAGS:

COMMON_FLAGS="-march=native -pipe -O3 -flto=8 -ffat-lto-objects -fuse-linker-plugin -fuse-ld=gold -fno-delete-null-pointer-checks -fgraphite-identity -floop-nest-optimize"
CFLAGS="${COMMON_FLAGS}"
CXXFLAGS="${COMMON_FLAGS} -fpermissive"

LDFLAGS="-Wl,-O3 -Wl,--sort-common -Wl,-flto=8 -Wl,--as-needed -ffat-lto-objects -fuse-linker-plugin -fuse-ld=gold -fno-delete-null-pointer-checks -fgraphite-identity -floop-nest-optimize"

Out of those, only really relevant here are "flto=8 -ffat-lto-objects"




a.l.e

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hi brane,

personally, i've never heared of LTO, so i really don't know if anybody has tried it in combination with scribus.

what you are quoting refers to qt5... but does not tell what the error is...

just a guess from my side: if you want to compile with LTO, could it be, that all libraries you want to bind should also be compiled with the same flag?
... as said: just a guess!

Brane212

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just a guess from my side: if you want to compile with LTO, could it be, that all libraries you want to bind should also be compiled with the same flag?
... as said: just a guess!

I have quite a few packages and libraries compiled with LTO. Until now, if there was a problem, it was exclusively during compile phase, not at runtime.

LTO doesn't cross a border between packages and libraries- it is just an optimisation that can be used between units of the same package- to the outside world, package compiled with LTO should behave just the same as ordinary one. Exception is static linking, but even that is handled in backwards-compatible manner and shouldn't make a difference.
« Last Edit: September 04, 2017, 05:38:42 pm by Brane212 »

a.l.e

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if you give me instructions on how to compile LTO enabled on a debian (testing) machine, i can give a try here and see if i face the same issue...

otherwise, well, you can try to write a ticket in the bug tracker (https://bugs.scribus.net) and see if jean or craig have a clue about this...

sorry, that i can't help you more with this...
a.l.e

 

palmate