https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90229
Bug ID: 90229
Summary: Interaction among -Wl,--as-needed and LTO results in
an undefined symbol
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: lto
Assignee: unassigned at gcc dot gnu.org
Reporter: marxin at gcc dot gnu.org
CC: marxin at gcc dot gnu.org
Target Milestone: ---
As seen in few openSUSE packages with LTO enabled:
https://bugzilla.opensuse.org/show_bug.cgi?id=1133232
https://bugzilla.opensuse.org/show_bug.cgi?id=1133131
There's some issue:
$ cat lib.cc
int FLAGS_verbose;
$ g++ -shared -fPIC lib.cc -o mylib.so
$ g++ -pthread 1.ii libpes.so -Wl,--as-needed -O
[OK]
But:
$ g++ -pthread 1.ii libpes.so -Wl,--as-needed -O -flto
/usr/lib64/gcc/x86_64-suse-linux/8/../../../../x86_64-suse-linux/bin/ld:
/usr/lib64/gcc/x86_64-suse-linux/8/libstdc++.so: undefined reference to
`pthread_create'
collect2: error: ld returned 1 exit status
