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Date: Thu, 09 May 2019 21:00:32 -0600
From: "Gang He" <ghe@suse.com>
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Subject: [linux-lvm] Does LVM2 support building with LTO enablement?
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To: linux-lvm@redhat.com

Hello List,

Our build team wants to build LVM2 with LTO enablement, but looks failed.
The error message likes,

[   30s] gcc -fmessage-length=0 -grecord-gcc-switches -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -flto=160 -g -fPIC  -L../libdm -L../lib -L../libdaemon/client -L../daemons/dmeventd -Wl,-z,relro,-z,now -pie -fPIE -Wl,--export-dynamic -o lvm command.o dumpconfig.o formats.o lvchange.o lvconvert.o lvconvert_poll.o lvcreate.o lvdisplay.o lvextend.o lvmcmdline.o lvmdiskscan.o lvreduce.o lvremove.o lvrename.o lvresize.o lvscan.o polldaemon.o pvchange.o pvck.o pvcreate.o pvdisplay.o pvmove.o pvmove_poll.o pvremove.o pvresize.o pvscan.o reporter.o segtypes.o tags.o toollib.o vgcfgbackup.o vgcfgrestore.o vgchange.o vgck.o vgcreate.o vgconvert.o vgdisplay.o vgexport.o vgextend.o vgimport.o vgmerge.o vgmknodes.o lvpoll.o vgimportclone.o vgreduce.o vgremove.o vgrename.o vgscan.o vgsplit.o  lvm.o \
[   30s] 	-llvm-internal -ldevmapper-event -ldaemonclient  -ludev -ldl -lblkid -ldevmapper -laio -lreadline 
[   30s] /usr/lib64/gcc/x86_64-suse-linux/9/../../../../x86_64-suse-linux/bin/ld: /tmp/lvm.vKOJS8.ltrans0.ltrans.o: in function `_async_wait':
[   30s] /home/abuild/rpmbuild/BUILD/LVM2.2.02.180/tools/device/bcache.c:268: undefined reference to `io_getevents'
[   30s] /usr/lib64/gcc/x86_64-suse-linux/9/../../../../x86_64-suse-linux/bin/ld: /usr/lib64/gcc/x86_64-suse-linux/9/../../../../lib64/libaio.so: undefined reference to `io_cancel'
[   30s] collect2: error: ld returned 1 exit status
[   30s] make[1]: *** [Makefile:143: lvm] Error 1
[   30s] make[1]: Leaving directory '/home/abuild/rpmbuild/BUILD/LVM2.2.02.180/tools'
[   30s] make[1]: *** Waiting for unfinished jobs....
[   30s] make[1]: Entering directory '/home/abuild/rpmbuild/BUILD/LVM2.2.02.180/tools'
[   30s]     [CC] liblvm2cmd.so

About LTO information, you can look at the links as below,
https://lists.opensuse.org/opensuse-factory/2019-04/msg00320.html 
https://en.opensuse.org/openSUSE:LTO 


Thanks
Gang