PowerPC ld segfault on script discarding dynamic sections

[Alan Modra <amodra at gmail dot com>]

Found when running the gold testsuite on an Ubuntu system where gcc
defaults to -pie, on attempting to link gold/memory_test.

bfd/
	* elf64-ppc.c (ppc64_elf_finish_dynamic_sections): Don't segfault
	on .got or .plt output section being discarded by script.
	* elf32-ppc.c (ppc_elf_finish_dynamic_sections): Likewise.  Move
	vxworks splt temp.
gold/
	* powerpc.cc (Target_powerpc::make_iplt_section): Check that
	output_section exists before attempting add_output_section_data.
	(Target_powerpc::make_brlt_section): Likewise.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index ac3f160..cf5c41b 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2017-02-22  Alan Modra  <amodra@gmail.com>
+
+	* elf64-ppc.c (ppc64_elf_finish_dynamic_sections): Don't segfault
+	on .got or .plt output section being discarded by script.
+	* elf32-ppc.c (ppc_elf_finish_dynamic_sections): Likewise.  Move
+	vxworks splt temp.
+
 2017-02-21  Alan Modra  <amodra@gmail.com>
 
 	* elf64-alpha.c (elf64_alpha_size_dynamic_sections): Only emit
diff --git a/bfd/elf32-ppc.c b/bfd/elf32-ppc.c
index 30998b1..d821935 100644
--- a/bfd/elf32-ppc.c
+++ b/bfd/elf32-ppc.c
@@ -10418,7 +10418,6 @@ ppc_elf_finish_dynamic_sections (bfd *output_bfd,
 				 struct bfd_link_info *info)
 {
   asection *sdyn;
-  asection *splt;
   struct ppc_elf_link_hash_table *htab;
   bfd_vma got;
   bfd *dynobj;
@@ -10431,10 +10430,6 @@ ppc_elf_finish_dynamic_sections (bfd *output_bfd,
   htab = ppc_elf_hash_table (info);
   dynobj = htab->elf.dynobj;
   sdyn = bfd_get_linker_section (dynobj, ".dynamic");
-  if (htab->is_vxworks)
-    splt = htab->elf.splt;
-  else
-    splt = NULL;
 
   got = 0;
   if (htab->elf.hgot != NULL)
@@ -10489,7 +10484,8 @@ ppc_elf_finish_dynamic_sections (bfd *output_bfd,
 	}
     }
 
-  if (htab->elf.sgot != NULL)
+  if (htab->elf.sgot != NULL
+      && htab->elf.sgot->output_section != bfd_abs_section_ptr)
     {
       if (htab->elf.hgot->root.u.def.section == htab->elf.sgot
 	  || htab->elf.hgot->root.u.def.section == htab->elf.sgotplt)
@@ -10531,8 +10527,12 @@ ppc_elf_finish_dynamic_sections (bfd *output_bfd,
     }
 
   /* Fill in the first entry in the VxWorks procedure linkage table.  */
-  if (splt && splt->size > 0)
+  if (htab->is_vxworks
+      && htab->elf.splt != NULL
+      && htab->elf.splt->size != 0
+      && htab->elf.splt->output_section != bfd_abs_section_ptr)
     {
+      asection *splt = htab->elf.splt;
       /* Use the right PLT. */
       const bfd_vma *plt_entry = (bfd_link_pic (info)
 				  ? ppc_elf_vxworks_pic_plt0_entry
diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index 56b94f9..4d90e0a 100644
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -15603,7 +15603,8 @@ ppc64_elf_finish_dynamic_sections (bfd *output_bfd,
 	}
     }
 
-  if (htab->elf.sgot != NULL && htab->elf.sgot->size != 0)
+  if (htab->elf.sgot != NULL && htab->elf.sgot->size != 0
+      && htab->elf.sgot->output_section != bfd_abs_section_ptr)
     {
       /* Fill in the first entry in the global offset table.
 	 We use it to hold the link-time TOCbase.  */
@@ -15615,7 +15616,8 @@ ppc64_elf_finish_dynamic_sections (bfd *output_bfd,
       elf_section_data (htab->elf.sgot->output_section)->this_hdr.sh_entsize = 8;
     }
 
-  if (htab->elf.splt != NULL && htab->elf.splt->size != 0)
+  if (htab->elf.splt != NULL && htab->elf.splt->size != 0
+      && htab->elf.splt->output_section != bfd_abs_section_ptr)
     {
       /* Set .plt entry size.  */
       elf_section_data (htab->elf.splt->output_section)->this_hdr.sh_entsize
diff --git a/gold/ChangeLog b/gold/ChangeLog
index 3f41834..4e1fb95 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,9 @@
+2017-02-22  Alan Modra  <amodra@gmail.com>
+
+	* powerpc.cc (Target_powerpc::make_iplt_section): Check that
+	output_section exists before attempting add_output_section_data.
+	(Target_powerpc::make_brlt_section): Likewise.
+
 2017-02-15  Vladimir Radosavljevic  <Vladimir.Radosavljevic@imgtec.com>
 
 	* mips.cc (Target_mips::Scan::get_reference_flags): Remove
diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index 4abfcec..1477a10 100644
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -3608,11 +3608,13 @@ Target_powerpc<size, big_endian>::make_iplt_section(Symbol_table* symtab,
       this->make_plt_section(symtab, layout);
 
       Reloc_section* iplt_rel = new Reloc_section(false);
-      this->rela_dyn_->output_section()->add_output_section_data(iplt_rel);
+      if (this->rela_dyn_->output_section())
+	this->rela_dyn_->output_section()->add_output_section_data(iplt_rel);
       this->iplt_
 	= new Output_data_plt_powerpc<size, big_endian>(this, iplt_rel,
 							"** IPLT");
-      this->plt_->output_section()->add_output_section_data(this->iplt_);
+      if (this->plt_->output_section())
+	this->plt_->output_section()->add_output_section_data(this->iplt_);
     }
 }
 
@@ -3708,14 +3710,16 @@ Target_powerpc<size, big_endian>::make_brlt_section(Layout* layout)
 	{
 	  // When PIC we can't fill in .branch_lt (like .plt it can be
 	  // a bss style section) but must initialise at runtime via
-	  // dynamic relocats.
+	  // dynamic relocations.
 	  this->rela_dyn_section(layout);
 	  brlt_rel = new Reloc_section(false);
-	  this->rela_dyn_->output_section()->add_output_section_data(brlt_rel);
+	  if (this->rela_dyn_->output_section())
+	    this->rela_dyn_->output_section()
+	      ->add_output_section_data(brlt_rel);
 	}
       this->brlt_section_
 	= new Output_data_brlt_powerpc<size, big_endian>(this, brlt_rel);
-      if (this->plt_ && is_pic)
+      if (this->plt_ && is_pic && this->plt_->output_section())
 	this->plt_->output_section()
 	  ->add_output_section_data(this->brlt_section_);
       else

-- 
Alan Modra
Australia Development Lab, IBM