PR22978, TLS local-dynamic incorrectly linked on hppa-linux

We were emitting dynamic relocs on the second word of a TLS GD GOT
entry pair (the dtprel offset), without the addend necessary when no
symbol is present on the dynamic reloc.  Unfortunately the simple
solution of providing the proper addend doesn't work due to an hppa
glibc ld.so bug that ignores such addends.  So instead optimize the
relocs.  The dtprel offset is known at link time for locally defined
symbols (the only case where we'll end up with no symbol on a dynamic
reloc) so we can omit the dynamic reloc in that case.

Furthermore, we can omit a dynamic reloc on the first word of a TLS GD
GOT entry pair (the module id) if the symbol is local and we are
producing an executable.  Similarly, a tprel reloc on a TLS IE GOT
entry is not needed for local symbols in an executable.  So the
condition for TLS GOT relocs can become bfd_link_dll(info) rather than
bfd_link_pic(info) as needed for normal GOT relocs.

This all presumes hppa ld.so doesn't need to differentiate TLS GD GOT
pairs from TLS LD GOT pairs, which is currently true.

	PR 22978
	* elf32-hppa.c (got_relocs_needed): Add extra param to special
	case both dtprel and tprel relocs.
	(allocate_dynrelocs): Adjust conditions for got relocs.
	(elf32_hppa_relocate_section): Likewise for local sym got relocs.
	Emit dynamic relocs on TLS GOT entries for shared libraries,
	not when pic.  Omit dynamic reloc on dtprel entry when local,
	and on tprel entry when local and executable.

2 files changed, 48 insertions, 32 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index d92c334..fa26810 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,14 @@
+2018-04-20  Alan Modra  <amodra@gmail.com>
+
+	PR 22978
+	* elf32-hppa.c (got_relocs_needed): Add extra param to special
+	case both dtprel and tprel relocs.
+	(allocate_dynrelocs): Adjust conditions for got relocs.
+	(elf32_hppa_relocate_section): Likewise for local sym got relocs.
+	Emit dynamic relocs on TLS GOT entries for shared libraries,
+	not when pic.  Omit dynamic reloc on dtprel entry when local,
+	and on tprel entry when local and executable.
+
 2018-04-19  Alan Modra  <amodra@gmail.com>
 
 	PR 22537
diff --git a/bfd/elf32-hppa.c b/bfd/elf32-hppa.c
index 44fb753..722452b 100644
--- a/bfd/elf32-hppa.c
+++ b/bfd/elf32-hppa.c
@@ -1894,18 +1894,19 @@ got_entries_needed (int tls_type)
 }
 
 /* Calculate size of relocs needed for symbol given its TLS_TYPE and
-   NEEDed GOT entries.  KNOWN says a TPREL offset can be calculated
-   at link time.  */
+   NEEDed GOT entries.  TPREL_KNOWN says a TPREL offset can be
+   calculated at link time.  DTPREL_KNOWN says the same for a DTPREL
+   offset.  */
 
 static inline unsigned int
-got_relocs_needed (int tls_type, unsigned int need, bfd_boolean known)
+got_relocs_needed (int tls_type, unsigned int need,
+		   bfd_boolean dtprel_known, bfd_boolean tprel_known)
 {
   /* All the entries we allocated need relocs.
-     Except IE in executable with a local symbol.  We could also omit
-     the DTPOFF reloc on the second word of a GD entry under the same
-     condition as that for IE, but ld.so might want to differentiate
-     LD and GD entries at some stage.  */
-  if ((tls_type & GOT_TLS_IE) != 0 && known)
+     Except for GD and IE with local symbols.  */
+  if ((tls_type & GOT_TLS_GD) != 0 && dtprel_known)
+    need -= GOT_ENTRY_SIZE;
+  if ((tls_type & GOT_TLS_IE) != 0 && tprel_known)
     need -= GOT_ENTRY_SIZE;
   return need * sizeof (Elf32_External_Rela) / GOT_ENTRY_SIZE;
 }
@@ -1959,15 +1960,16 @@ allocate_dynrelocs (struct elf_link_hash_entry *eh, void *inf)
       need = got_entries_needed (hh->tls_type);
       sec->size += need;
       if (htab->etab.dynamic_sections_created
-	  && (bfd_link_pic (info)
+	  && (bfd_link_dll (info)
+	      || (bfd_link_pic (info) && (hh->tls_type & GOT_NORMAL) != 0)
 	      || (eh->dynindx != -1
 		  && !SYMBOL_REFERENCES_LOCAL (info, eh)))
 	  && !UNDEFWEAK_NO_DYNAMIC_RELOC (info, eh))
 	{
-	  bfd_boolean tprel_known = (bfd_link_executable (info)
-				     && SYMBOL_REFERENCES_LOCAL (info, eh));
+	  bfd_boolean local = SYMBOL_REFERENCES_LOCAL (info, eh);
 	  htab->etab.srelgot->size
-	    += got_relocs_needed (hh->tls_type, need, tprel_known);
+	    += got_relocs_needed (hh->tls_type, need, local,
+				  local && bfd_link_executable (info));
 	}
     }
   else
@@ -2192,12 +2194,12 @@ elf32_hppa_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
 	      *local_got = sec->size;
 	      need = got_entries_needed (*local_tls_type);
 	      sec->size += need;
-	      if (bfd_link_pic (info))
-		{
-		  bfd_boolean tprel_known = bfd_link_executable (info);
-		  htab->etab.srelgot->size
-		    += got_relocs_needed (*local_tls_type, need, tprel_known);
-		}
+	      if (bfd_link_dll (info)
+		  || (bfd_link_pic (info)
+		      && (*local_tls_type & GOT_NORMAL) != 0))
+		htab->etab.srelgot->size
+		  += got_relocs_needed (*local_tls_type, need, TRUE,
+					bfd_link_executable (info));
 	    }
 	  else
 	    *local_got = (bfd_vma) -1;
@@ -4041,7 +4043,7 @@ elf32_hppa_relocate_section (bfd *output_bfd,
 		   GD GOT are necessary, we emit the GD first.  */
 
 		if (indx != 0
-		    || (bfd_link_pic (info)
+		    || (bfd_link_dll (info)
 			&& (hh == NULL
 			    || !UNDEFWEAK_NO_DYNAMIC_RELOC (info, &hh->eh))))
 		  {
@@ -4065,6 +4067,20 @@ elf32_hppa_relocate_section (bfd *output_bfd,
 			bfd_elf32_swap_reloca_out (output_bfd, &outrel, loc);
 			htab->etab.srelgot->reloc_count++;
 			loc += sizeof (Elf32_External_Rela);
+			bfd_put_32 (output_bfd, 0,
+				    htab->etab.sgot->contents + cur_off);
+		      }
+		    else
+		      /* If we are not emitting relocations for a
+			 general dynamic reference, then we must be in a
+			 static link or an executable link with the
+			 symbol binding locally.  Mark it as belonging
+			 to module 1, the executable.  */
+		      bfd_put_32 (output_bfd, 1,
+				  htab->etab.sgot->contents + cur_off);
+
+		    if (indx != 0)
+		      {
 			outrel.r_info
 			  = ELF32_R_INFO (indx, R_PARISC_TLS_DTPOFF32);
 			outrel.r_offset += 4;
@@ -4072,22 +4088,11 @@ elf32_hppa_relocate_section (bfd *output_bfd,
 			htab->etab.srelgot->reloc_count++;
 			loc += sizeof (Elf32_External_Rela);
 			bfd_put_32 (output_bfd, 0,
-				    htab->etab.sgot->contents + cur_off);
-			bfd_put_32 (output_bfd, 0,
 				    htab->etab.sgot->contents + cur_off + 4);
 		      }
 		    else
-		      {
-			/* If we are not emitting relocations for a
-			   general dynamic reference, then we must be in a
-			   static link or an executable link with the
-			   symbol binding locally.  Mark it as belonging
-			   to module 1, the executable.  */
-			bfd_put_32 (output_bfd, 1,
-				    htab->etab.sgot->contents + cur_off);
-			bfd_put_32 (output_bfd, relocation - dtpoff_base (info),
-				    htab->etab.sgot->contents + cur_off + 4);
-		      }
+		      bfd_put_32 (output_bfd, relocation - dtpoff_base (info),
+				  htab->etab.sgot->contents + cur_off + 4);
 		    cur_off += 8;
 		  }