Don't mess up RelIplt symbols during relocatable processing
Summary:
During upgrading of the FreeBSD source tree with lld 7.0.0, I noticed
that it started complaining about crt1.o having an "index past the
end of the symbol table".
Such a symbol table looks approximately like this, viewed with
readelf -s (note the Ndx field being messed up):
Symbol table '.symtab' contains 4 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 SECTION LOCAL DEFAULT 1
2: 00000000 0 NOTYPE WEAK HIDDEN RSV[0xffff] __rel_iplt_end
3: 00000000 0 NOTYPE WEAK HIDDEN RSV[0xffff] __rel_iplt_start
At first, it seemed that recent ifunc relocation work had caused this:
<https://reviews.freebsd.org/rS339351>, but it turned out that it was
due to incorrect processing of the object files by lld, when using -r
(a.k.a. --relocatable).
Bisecting showed that rL324421 ("Convert a use of Config->Static") was
the commit where this new behavior began. Simply reverting it solved
the issue, and the __rel_iplt symbols had an index of UND again.
Looking at Rafael's commit message, I think he simply missed the
possibility of --relocatable being in effect, so I have added an
additional check for it.
I also added a simple regression test case.
Reviewers: grimar, ruiu, emaste, espindola
Reviewed By: ruiu
Subscribers: arichardson, krytarowski, llvm-commits
Differential Revision: https://reviews.llvm.org/D53515
This fixes a problem in lld where it places incorrect indexes for ifunc
related symbols in crt1.o and friends, making it impossible to link most
normal programs with it.
8fe1b0abe6