On Mon, Dec 21, 2015 at 4:55 AM, Adhemerval Zanella adhemerval.zanella@linaro.org wrote:
This mix of LTO and non-LTO object files is not supported by upstream binutils unless a patch from H.J. Lu is applied. That patch has been available since 2013 and was last refreshed in his 2.25.51.0.4 branch last September. It is accessible here:
November 2013 is when we switched from svn to git, which is why the git branch was created then.
I tracked the bulk of the patch back to April 2011, though some new LTO related testsuite changes date back to January 2011. The initial patch submission for the bulk of the patch appears to be https://sourceware.org/ml/binutils/2011-04/msg00275.html It is a large patch, and HJ had to update it twice in the next 24 hours to fix problems with it. The size would have discouraged an immediate review. And the fact that it was updated twice in 24 hours after posting would have discouraged reviewers even more. People were perhaps waiting for the final version of the patch before trying to review it, and then accidentally forgot about it along the way. I don't see any discussion of the patch at the time. And I haven't seen any attempt to resubmit it, though I could have missed something.
I see that the issue was discussed earlier in December 2010. HJ made a proposal for a fix, and there was feedback at that time. https://gcc.gnu.org/ml/gcc/2010-12/msg00229.html it looks like there were 3 separate related threads which may have confused the issue a bit. https://sourceware.org/ml/binutils/2010-12/msg00012.html https://sourceware.org/ml/binutils/2010-12/msg00182.html https://sourceware.org/ml/binutils/2010-12/msg00231.html
Anyways, the size of the patch suggests using caution and waiting for upstream review. Though I did find a reference that suggests Fedora is using it https://lists.fedoraproject.org/pipermail/scm-commits/Week-of-Mon-20130513/1... which suggests that it may be well tested. This was done by Nick Clifton, who is one of the binutils maintainers, so maybe we just need someone to ask about the status of the patch on the binutils mailing list to remind people that it still needs to be reviewed for the upstream FSF binutils tree.
Jim