From 8fe1b0abe62fe10b7c761a0270e8631b693e6751 Mon Sep 17 00:00:00 2001 From: dim Date: Tue, 23 Oct 2018 20:56:59 +0000 Subject: [PATCH] Pull in r345002 from upstream lld trunk: 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: , 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. --- contrib/llvm/tools/lld/ELF/Writer.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/contrib/llvm/tools/lld/ELF/Writer.cpp b/contrib/llvm/tools/lld/ELF/Writer.cpp index d9f445c2923..21c0fba206a 100644 --- a/contrib/llvm/tools/lld/ELF/Writer.cpp +++ b/contrib/llvm/tools/lld/ELF/Writer.cpp @@ -874,7 +874,7 @@ void PhdrEntry::add(OutputSection *Sec) { // need these symbols, since IRELATIVE relocs are resolved through GOT // and PLT. For details, see http://www.airs.com/blog/archives/403. template void Writer::addRelIpltSymbols() { - if (needsInterpSection()) + if (Config->Relocatable || needsInterpSection()) return; StringRef S = Config->IsRela ? "__rela_iplt_start" : "__rel_iplt_start"; addOptionalRegular(S, InX::RelaIplt, 0, STV_HIDDEN, STB_WEAK); -- 2.45.0