[binutils-gdb] x86: Keep the unused _GLOBAL_OFFSET_TABLE_ for Solaris

[H.J.Lu <hjl at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=dc11dea21281758b71113c03a8d8be92d175a46c

commit dc11dea21281758b71113c03a8d8be92d175a46c
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Feb 8 13:52:22 2018 -0800

    x86: Keep the unused _GLOBAL_OFFSET_TABLE_ for Solaris
    
    Solaris requires to keep _GLOBAL_OFFSET_TABLE_ even if it isn't used.
    This patch detects Solaris target and keeps _GLOBAL_OFFSET_TABLE_ for
    Solaris.
    
    	* elf32-i386.c (elf32_i386_copy_solaris_special_section_fields):
    	New prototype.
    	(elf_i386_link_setup_gnu_properties): Set need_global_offset_table
    	for Solaris.
    	* elf64-x86-64.c (elf64_x86_64_copy_solaris_special_section_fields):
    	New prototype.
    	(elf_x86_64_link_setup_gnu_properties): Set
    	need_global_offset_table for Solaris.
    	* elfxx-x86.c (_bfd_x86_elf_size_dynamic_sections): Keep the
    	unused _GLOBAL_OFFSET_TABLE_ for Solaris.
    	(_bfd_x86_elf_link_setup_gnu_properties): Copy
    	need_global_offset_table.
    	* elfxx-x86.h (elf_x86_link_hash_table): Add
    	need_global_offset_table.
    	(elf_x86_init_table): Likewise.

Diff:
---
 bfd/ChangeLog      | 18 ++++++++++++++++++
 bfd/elf32-i386.c   |  9 +++++++++
 bfd/elf64-x86-64.c |  9 +++++++++
 bfd/elfxx-x86.c    |  4 +++-
 bfd/elfxx-x86.h    |  6 ++++++
 5 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 0cd219b..0b27eb0 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,21 @@
+2018-02-08  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* elf32-i386.c (elf32_i386_copy_solaris_special_section_fields):
+	New prototype.
+	(elf_i386_link_setup_gnu_properties): Set need_global_offset_table
+	for Solaris.
+	* elf64-x86-64.c (elf64_x86_64_copy_solaris_special_section_fields):
+	New prototype.
+	(elf_x86_64_link_setup_gnu_properties): Set
+	need_global_offset_table for Solaris.
+	* elfxx-x86.c (_bfd_x86_elf_size_dynamic_sections): Keep the
+	unused _GLOBAL_OFFSET_TABLE_ for Solaris.
+	(_bfd_x86_elf_link_setup_gnu_properties): Copy
+	need_global_offset_table.
+	* elfxx-x86.h (elf_x86_link_hash_table): Add
+	need_global_offset_table.
+	(elf_x86_init_table): Likewise.
+
 2018-02-08  Jim Wilson  <jimw@sifive.com>
 
 	* elfnn-riscv.c (riscv_elf_relocate_section): Add comment for previous
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 1bdf3d4..4988359 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -29,6 +29,9 @@
 
 #include "elf/i386.h"
 
+static bfd_boolean elf32_i386_copy_solaris_special_section_fields
+  (const bfd *, bfd *, const Elf_Internal_Shdr *, Elf_Internal_Shdr *);
+
 static reloc_howto_type elf_howto_table[]=
 {
   HOWTO(R_386_NONE, 0, 3, 0, FALSE, 0, complain_overflow_dont,
@@ -4345,6 +4348,7 @@ static bfd *
 elf_i386_link_setup_gnu_properties (struct bfd_link_info *info)
 {
   struct elf_x86_init_table init_table;
+  const struct elf_backend_data *bed;
 
   switch (get_elf_x86_backend_data (info->output_bfd)->target_os)
     {
@@ -4374,6 +4378,11 @@ elf_i386_link_setup_gnu_properties (struct bfd_link_info *info)
   init_table.r_info = elf32_r_info;
   init_table.r_sym = elf32_r_sym;
 
+  bed = get_elf_backend_data (info->output_bfd);
+  init_table.need_global_offset_table
+    = (bed->elf_backend_copy_special_section_fields
+       == elf32_i386_copy_solaris_special_section_fields);
+
   return _bfd_x86_elf_link_setup_gnu_properties (info, &init_table);
 }
 
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index aad9b85..7fa0408 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -27,6 +27,9 @@
 #include "opcode/i386.h"
 #include "elf/x86-64.h"
 
+static bfd_boolean elf64_x86_64_copy_solaris_special_section_fields
+  (const bfd *, bfd *, const Elf_Internal_Shdr *, Elf_Internal_Shdr *);
+
 #ifdef CORE_HEADER
 #include <stdarg.h>
 #include CORE_HEADER
@@ -4858,6 +4861,7 @@ static bfd *
 elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
 {
   struct elf_x86_init_table init_table;
+  const struct elf_backend_data *bed;
 
   if ((int) R_X86_64_standard >= (int) R_X86_64_converted_reloc_bit
       || (int) R_X86_64_max <= (int) R_X86_64_converted_reloc_bit
@@ -4914,6 +4918,11 @@ elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
       init_table.r_sym = elf32_r_sym;
     }
 
+  bed = get_elf_backend_data (info->output_bfd);
+  init_table.need_global_offset_table
+    = (bed->elf_backend_copy_special_section_fields
+       == elf64_x86_64_copy_solaris_special_section_fields);
+
   return _bfd_x86_elf_link_setup_gnu_properties (info, &init_table);
 }
 
diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
index dbda542..b0eb1c8 100644
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@@ -1098,7 +1098,8 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd,
 	      || htab->elf.igotplt->size == 0))
 	{
 	  htab->elf.sgotplt->size = 0;
-	  if (htab->elf.hgot != NULL)
+	  if (htab->elf.hgot != NULL
+	      && !htab->need_global_offset_table)
 	    {
 	      /* Remove the unused _GLOBAL_OFFSET_TABLE_ from symbol
 		 table. */
@@ -2463,6 +2464,7 @@ error_alignment:
     return pbfd;
 
   htab->plt0_pad_byte = init_table->plt0_pad_byte;
+  htab->need_global_offset_table = init_table->need_global_offset_table;
 
   use_ibt_plt = info->ibtplt || info->ibt;
   if (!use_ibt_plt && pbfd != NULL)
diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h
index b515ee6..4606bf1 100644
--- a/bfd/elfxx-x86.h
+++ b/bfd/elfxx-x86.h
@@ -481,6 +481,9 @@ struct elf_x86_link_hash_table
   /* TRUE if GOT is referenced.  */
   unsigned int got_referenced : 1;
 
+  /* TRUE if _GLOBAL_OFFSET_TABLE_ is needed.  */
+  unsigned int need_global_offset_table : 1;
+
   bfd_vma (*r_info) (bfd_vma, bfd_vma);
   bfd_vma (*r_sym) (bfd_vma);
   bfd_boolean (*is_reloc_section) (const char *);
@@ -525,6 +528,9 @@ struct elf_x86_init_table
 
   bfd_byte plt0_pad_byte;
 
+  /* TRUE if _GLOBAL_OFFSET_TABLE_ is needed.  */
+  unsigned int need_global_offset_table : 1;
+
   bfd_vma (*r_info) (bfd_vma, bfd_vma);
   bfd_vma (*r_sym) (bfd_vma);
 };