Commits on Feb 16, 2024

1. [lld/ELF] Avoid unnecessary TPOFF relocations in GOT for -pie (llvm#8… …

   …1739)
   
   With the new SystemZ port we noticed that -pie executables generated
   from files containing R_390_TLS_IEENT relocations will have unnecessary
   relocations in their GOT:
   
                           9e8d8: R_390_TLS_TPOFF  *ABS*+0x18
   
   This is caused by the config->isPic conditon in addTpOffsetGotEntry:
   
    static void addTpOffsetGotEntry(Symbol &sym) {
      in.got->addEntry(sym);
      uint64_t off = sym.getGotOffset();
      if (!sym.isPreemptible && !config->isPic) {
        in.got->addConstant({R_TPREL, target->symbolicRel, off, 0, &sym});
        return;
      }
   
   It is correct that we need to retain a TPOFF relocation if the target
   symbol is preemptible or if we're building a shared library. But when
   building a -pie executable, those values are fixed at link time and
   there's no need for any remaining dynamic relocation.
   
   Note that the equivalent MIPS-specific code in MipsGotSection::build
   checks for config->shared instead of config->isPic; we should use the
   same check here. (Note also that on many other platforms we're not even
   using addTpOffsetGotEntry in this case as an IE->LE relaxation is
   applied before; we don't have this type of relaxation on SystemZ.)
   
   (cherry picked from commit 6f90773)

   

   uweigand authored and tstellar committed Feb 16, 2024
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