ELF: Reword a somewhat misleading error message.

[pcc]

Summary

PT_TLS is a type of program header, so we wouldn't expect to see
one in an object file. This error should probably be referring to
the fact that we didn't see a section with the flag SHF_TLS, which
would normally cause us to create a PT_TLS program header.

[ruiu]

LGTM

lld/trunk/ELF/Symbols.cpp

case SymbolBody::DefinedRegularKind: {
     // If you understand the data structures involved with this next
     // line (and how they get built), then you have a pretty good
     // understanding of the linker.
     uint64_t VA = (OutSec ? OutSec->Addr : 0) + IS->getOffset(Offset);
 
     if (D.isTls() && !Config->Relocatable) {
       if (!Out::TlsPhdr)
         fatal(toString(D.File) +
-              " has a STT_TLS symbol but doesn't have a PT_TLS section");
+              " has an STT_TLS symbol but doesn't have an SHF_TLS section");
       return VA - Out::TlsPhdr->p_vaddr;
     }
     return VA;
   }
   case SymbolBody::DefinedCommonKind:
     if (!Config->DefineCommon)
       return 0;
     return InX::Common->getParent()->Addr + InX::Common->OutSecOff +

lld/trunk/test/ELF/invalid/tls-symbol.s

 # REQUIRES: x86
 
-## The test file contains a STT_TLS symbol but has no TLS section.
+## The test file contains an STT_TLS symbol but has no TLS section.
 # RUN: not ld.lld %S/Inputs/tls-symbol.elf -o %t 2>&1 | FileCheck %s
-# CHECK: has a STT_TLS symbol but doesn't have a PT_TLS section
+# CHECK: has an STT_TLS symbol but doesn't have an SHF_TLS section