commit 79c12faeea57e61364b6a7a3e411b096edce989c
Author: Andreas Krebbel <krebbel@linux.vnet.ibm.com>
Date:   Fri Jul 28 17:59:25 2017 +0200

    S/390: Fix segfault when linking -shared -nostartfiles
    
    Regression-tested on s390x.
    
    bfd/ChangeLog:
    
    2017-07-28  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
    
            * elf32-s390.c (elf_s390_finish_dynamic_sections): Add NULL
            pointer check for htab->elf.irelplt.
            * elf64-s390.c (elf_s390_finish_dynamic_sections): Likewise.

--- a/bfd/elf32-s390.c
+++ b/bfd/elf32-s390.c
@@ -3941,7 +3941,9 @@ elf_s390_finish_dynamic_sections (bfd *output_bfd,
 	      break;
 
 	    case DT_PLTRELSZ:
-	      dyn.d_un.d_val = htab->elf.srelplt->size + htab->elf.irelplt->size;
+	      dyn.d_un.d_val = htab->elf.srelplt->size;
+	      if (htab->elf.irelplt)
+		dyn.d_un.d_val += htab->elf.irelplt->size;
 	      break;
 	    }
 
--- a/bfd/elf64-s390.c
+++ b/bfd/elf64-s390.c
@@ -3745,7 +3745,9 @@ elf_s390_finish_dynamic_sections (bfd *output_bfd,
 	      break;
 
 	    case DT_PLTRELSZ:
-	      dyn.d_un.d_val = htab->elf.srelplt->size + htab->elf.irelplt->size;
+	      dyn.d_un.d_val = htab->elf.srelplt->size;
+	      if (htab->elf.irelplt)
+		dyn.d_un.d_val += htab->elf.irelplt->size;
 	      break;
 
 	    case DT_RELASZ:
@@ -3756,7 +3758,9 @@ elf_s390_finish_dynamic_sections (bfd *output_bfd,
 		 linker script arranges for .rela.plt to follow all
 		 other relocation sections, we don't have to worry
 		 about changing the DT_RELA entry.  */
-	      dyn.d_un.d_val -= htab->elf.srelplt->size + htab->elf.irelplt->size;
+	      dyn.d_un.d_val -= htab->elf.srelplt->size;
+	      if (htab->elf.irelplt)
+		dyn.d_un.d_val -= htab->elf.irelplt->size;
 	      break;
 	    }