------- Comment #1 from pinskia at gmail dot com 2010-04-06 03:01 ------- Subject: Re: New: -flto doesn't remember -fPIC
This is done on purpose. The -fpic is needed on the link line too. This is a bug in libtool. Sent from my iPhone On Apr 5, 2010, at 6:47 PM, "debian-gcc at lists dot debian dot org" <gcc-bugzi...@gcc.gnu.org > wrote: > [forwarded from http://bugs.debian.org/524176] > > Matthias > > gcc-4.5 with -flto doesn't work with -fPIC properly. > > Simple testcase: > int entry(int a) > { > return bar(a)+1; > } > > int bar(int a) > { > return a+4; > } > > $ gcc-4.5 foo1.c -flto -fPIC -DPIC -c > $ gcc-4.5 foo2.c -flto -fPIC -DPIC -c > $ gcc-4.5 foo1.o foo2.o -flto -shared > /usr/bin/ld: /tmp/ccmA7RCK.lto.o: relocation R_X86_64_PC32 against > symbol `bar' > can not be used when making a shared object; recompile with -fPIC > /usr/bin/ld: final link failed: Bad value > collect2: ld returned 1 exit status > > This works however: > $ gcc-4.5 foo1.o foo2.o -flto -shared -fPIC > > Now -fPIC is something libtool automatically adds, and I it doesn't > add it at > linktime (perhaps other build systems don't either). > Could gcc's -flto see that all .o files involved in the link are - > fPIC... and > make the resulting file -fPIC too? > Or at least it should see the -shared in the linker line, and > automatically use > -fPIC when -flto is used. > > > -- > Summary: -flto doesn't remember -fPIC > Product: gcc > Version: 4.5.0 > Status: UNCONFIRMED > Severity: normal > Priority: P3 > Component: lto > AssignedTo: unassigned at gcc dot gnu dot org > ReportedBy: debian-gcc at lists dot debian dot org > > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43659 > -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43659
