[PATCH] S/390: Add support for GNU attribute vector ABI tag

[Andreas Krebbel <krebbel at linux dot vnet dot ibm dot com>]

Hi,

the attached patch introduces the Tag_GNU_S390_ABI_Vector value for
.gnu_attribute.  It will be used in the future to mark binaries with
an ABI marker which then will be used e.g. by GDB to issue the proper
inferior function calls.

Bye,

-Andreas-


bfd/

2015-04-21  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* elf-s390-common.c (elf_s390_merge_obj_attributes): New function.
	* elf32-s390.c (elf32_s390_merge_private_bfd_data): Call
	elf_s390_merge_obj_attributes.
	* elf64-s390.c (elf64_s390_merge_private_bfd_data): New function.

binutils/

2015-04-21  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* readelf.c (display_s390_gnu_attribute): New function.
	(process_s390_specific): New function.
	(process_arch_specific): Call process_s390_specific.

gas/

2015-04-21  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* doc/as.texinfo: Document Tag_GNU_S390_ABI_Vector.


include/elf/

2015-04-21  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* s390.h: Define Tag_GNU_S390_ABI_Vector.


diff --git a/bfd/elf-s390-common.c b/bfd/elf-s390-common.c
index 462da16..dc6f55b 100644
--- a/bfd/elf-s390-common.c
+++ b/bfd/elf-s390-common.c
@@ -254,3 +254,61 @@ elf_s390_elf_sort_relocs_p (asection *sec)
 {
   return (sec->flags & SEC_CODE) == 0;
 }
+
+/* Merge object attributes from IBFD into OBFD.  Raise an error if
+   there are conflicting attributes.  */
+static bfd_boolean
+elf_s390_merge_obj_attributes (bfd *ibfd, bfd *obfd)
+{
+  obj_attribute *in_attr, *in_attrs;
+  obj_attribute *out_attr, *out_attrs;
+
+  if (!elf_known_obj_attributes_proc (obfd)[0].i)
+    {
+      /* This is the first object.  Copy the attributes.  */
+      _bfd_elf_copy_obj_attributes (ibfd, obfd);
+
+      /* Use the Tag_null value to indicate the attributes have been
+	 initialized.  */
+      elf_known_obj_attributes_proc (obfd)[0].i = 1;
+
+      return TRUE;
+    }
+
+  in_attrs = elf_known_obj_attributes (ibfd)[OBJ_ATTR_GNU];
+  out_attrs = elf_known_obj_attributes (obfd)[OBJ_ATTR_GNU];
+
+  /* Check for conflicting Tag_GNU_S390_ABI_Vector attributes and
+     merge non-conflicting ones.  */
+  in_attr = &in_attrs[Tag_GNU_S390_ABI_Vector];
+  out_attr = &out_attrs[Tag_GNU_S390_ABI_Vector];
+
+  if (in_attr->i > 2)
+    _bfd_error_handler
+      (_("Warning: %B uses unknown vector ABI %d"), ibfd,
+       in_attr->i);
+  else if (out_attr->i > 2)
+    _bfd_error_handler
+      (_("Warning: %B uses unknown vector ABI %d"), obfd,
+       out_attr->i);
+  else if (in_attr->i != out_attr->i)
+    {
+      out_attr->type = ATTR_TYPE_FLAG_INT_VAL;
+
+      if (in_attr->i && out_attr->i)
+	{
+	  const char abi_str[3][9] = { "none", "software", "hardware" };
+
+	  _bfd_error_handler
+	    (_("Warning: %B uses vector %s ABI, %B uses %s ABI"),
+	     ibfd, obfd, abi_str[in_attr->i], abi_str[out_attr->i]);
+	}
+      if (in_attr->i > out_attr->i)
+	out_attr->i = in_attr->i;
+    }
+
+  /* Merge Tag_compatibility attributes and any common GNU ones.  */
+  _bfd_elf_merge_object_attributes (ibfd, obfd);
+
+  return TRUE;
+}
diff --git a/bfd/elf32-s390.c b/bfd/elf32-s390.c
index 0127eab..19ba044 100644
--- a/bfd/elf32-s390.c
+++ b/bfd/elf32-s390.c
@@ -3980,9 +3980,18 @@ elf_s390_plt_sym_val (bfd_vma i, const asection *plt,
   return plt->vma + PLT_FIRST_ENTRY_SIZE + i * PLT_ENTRY_SIZE;
 }
 
+/* Merge backend specific data from an object file to the output
+   object file when linking.  */
+
 static bfd_boolean
 elf32_s390_merge_private_bfd_data (bfd *ibfd, bfd *obfd)
 {
+  if (!is_s390_elf (ibfd) || !is_s390_elf (obfd))
+    return TRUE;
+
+  if (!elf_s390_merge_obj_attributes (ibfd, obfd))
+    return FALSE;
+
   elf_elfheader (obfd)->e_flags |= elf_elfheader (ibfd)->e_flags;
   return TRUE;
 }
diff --git a/bfd/elf64-s390.c b/bfd/elf64-s390.c
index f06b58a..c9db954 100644
--- a/bfd/elf64-s390.c
+++ b/bfd/elf64-s390.c
@@ -3766,6 +3766,21 @@ elf_s390_plt_sym_val (bfd_vma i, const asection *plt,
   return plt->vma + PLT_FIRST_ENTRY_SIZE + i * PLT_ENTRY_SIZE;
 }
 
+/* Merge backend specific data from an object file to the output
+   object file when linking.  */
+
+static bfd_boolean
+elf64_s390_merge_private_bfd_data (bfd *ibfd, bfd *obfd)
+{
+  if (!is_s390_elf (ibfd) || !is_s390_elf (obfd))
+    return TRUE;
+
+  if (!elf_s390_merge_obj_attributes (ibfd, obfd))
+    return FALSE;
+
+  return TRUE;
+}
+
 /* Why was the hash table entry size definition changed from
    ARCH_SIZE/8 to 4? This breaks the 64 bit dynamic linker and
    this is the only reason for the s390_elf64_size_info structure.  */
@@ -3824,7 +3839,8 @@ const struct elf_size_info s390_elf64_size_info =
 #define bfd_elf64_bfd_is_local_label_name     elf_s390_is_local_label_name
 #define bfd_elf64_bfd_link_hash_table_create  elf_s390_link_hash_table_create
 #define bfd_elf64_bfd_reloc_type_lookup	      elf_s390_reloc_type_lookup
-#define bfd_elf64_bfd_reloc_name_lookup elf_s390_reloc_name_lookup
+#define bfd_elf64_bfd_reloc_name_lookup       elf_s390_reloc_name_lookup
+#define bfd_elf64_bfd_merge_private_bfd_data  elf64_s390_merge_private_bfd_data
 
 #define elf_backend_adjust_dynamic_symbol     elf_s390_adjust_dynamic_symbol
 #define elf_backend_check_relocs	      elf_s390_check_relocs
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 1533806..f82a433 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -12842,6 +12842,41 @@ display_power_gnu_attribute (unsigned char * p,
   return display_tag_value (tag & 1, p, end);
 }
 
+static unsigned char *
+display_s390_gnu_attribute (unsigned char * p,
+			    int tag,
+			    const unsigned char * const end)
+{
+  unsigned int len;
+  int val;
+
+  if (tag == Tag_GNU_S390_ABI_Vector)
+    {
+      val = read_uleb128 (p, &len, end);
+      p += len;
+      printf ("  Tag_GNU_S390_ABI_Vector: ");
+
+      switch (val)
+	{
+	case 0:
+	  printf (_("any\n"));
+	  break;
+	case 1:
+	  printf (_("software\n"));
+	  break;
+	case 2:
+	  printf (_("hardware\n"));
+	  break;
+	default:
+	  printf ("??? (%d)\n", val);
+	  break;
+	}
+      return p;
+   }
+
+  return display_tag_value (tag & 1, p, end);
+}
+
 static void
 display_sparc_hwcaps (int mask)
 {
@@ -13613,6 +13648,13 @@ process_power_specific (FILE * file)
 }
 
 static int
+process_s390_specific (FILE * file)
+{
+  return process_attributes (file, NULL, SHT_GNU_ATTRIBUTES, NULL,
+			     display_s390_gnu_attribute);
+}
+
+static int
 process_sparc_specific (FILE * file)
 {
   return process_attributes (file, NULL, SHT_GNU_ATTRIBUTES, NULL,
@@ -15606,6 +15648,10 @@ process_arch_specific (FILE * file)
     case EM_PPC:
       return process_power_specific (file);
       break;
+    case EM_S390:
+    case EM_S390_OLD:
+      return process_s390_specific (file);
+      break;
     case EM_SPARC:
     case EM_SPARC32PLUS:
     case EM_SPARCV9:
diff --git a/gas/doc/as.texinfo b/gas/doc/as.texinfo
index 1c2fe08..ffdb978 100644
--- a/gas/doc/as.texinfo
+++ b/gas/doc/as.texinfo
@@ -7126,6 +7126,22 @@ The vector ABI used by this object file.  The value will be:
 @end itemize
 @end table
 
+@subsection IBM z Systems Attributes
+
+@table @r
+@item Tag_GNU_S390_ABI_Vector (8)
+The vector ABI used by this object file.  The value will be:
+
+@itemize @bullet
+@item
+0 for files not affected by the vector ABI.
+@item
+1 for files using software vector ABI.
+@item
+2 for files using hardware vector ABI.
+@end itemize
+@end table
+
 @node Defining New Object Attributes
 @section Defining New Object Attributes
 
diff --git a/include/elf/s390.h b/include/elf/s390.h
index 0642d2e..57bbadd 100644
--- a/include/elf/s390.h
+++ b/include/elf/s390.h
@@ -129,6 +129,17 @@ START_RELOC_NUMBERS (elf_s390_reloc_type)
     RELOC_NUMBER (R_390_GNU_VTENTRY, 251)
 END_RELOC_NUMBERS (R_390_max)
 
-#endif /* _ELF_390_H */
-
+/* Object attribute tags.  */
+enum
+{
+  /* 0-3 are generic. */
+  /* 4 is reserved for the FP ABI. */
+
+  /* Vector ABI:
+     0 = not affected by the vector ABI, or not tagged.
+     1 = software vector ABI being used
+     2 = hardware vector ABI being used.  */
+  Tag_GNU_S390_ABI_Vector = 8,
+};
 
+#endif /* _ELF_390_H */
-- 
1.9.3