arc/nps400 : New cmem instructions and associated relocation

Add support for arc/nps400 cmem instructions, these load and store
instructions are hard-wired to access "0x57f00000 + 16-bit-offset".

Supporting this relocation required some additions to the arc relocation
handling in the bfd library, as well as the standard changes required to
add a new relocation type.

There's a test of the new instructions in the assembler, and a test of
the relocation in the linker.

bfd/ChangeLog:

	* reloc.c: Add BFD_RELOC_ARC_NPS_CMEM16 entry.
	* bfd-in2.h: Regenerate.
	* libbfd.h: Regenerate.
	* elf32-arc.c: Add 'opcode/arc.h' include.
	(struct arc_relocation_data): Add symbol_name.
	(arc_special_overflow_checks): New function.
	(arc_do_relocation): Use arc_special_overflow_checks, reindent as
	required, add an extra comment.
	(elf_arc_relocate_section): Setup symbol_name in reloc_data.

gas/ChangeLog:

	* testsuite/gas/arc/nps400-3.d: New file.
	* testsuite/gas/arc/nps400-3.s: New file.

include/ChangeLog:

	* elf/arc-reloc.def: Add ARC_NPS_CMEM16 reloc.
	* opcode/arc.h (NPS_CMEM_HIGH_VALUE): Define.

ld/ChangeLog:

	* testsuite/ld-arc/arc.exp: New file.
	* testsuite/ld-arc/nps-1.s: New file.
	* testsuite/ld-arc/nps-1a.d: New file.
	* testsuite/ld-arc/nps-1b.d: New file.
	* testsuite/ld-arc/nps-1b.err: New file.

opcodes/ChangeLog:

	* arc-nps400-tbl.h: Add xldb, xldw, xld, xstb, xstw, and xst
	instructions.
	* arc-opc.c (insert_nps_cmem_uimm16): New function.
	(extract_nps_cmem_uimm16): New function.
	(arc_operands): Add NPS_XLDST_UIMM16 operand.

1 files changed, 74 insertions, 19 deletions

diff --git a/bfd/elf32-arc.c b/bfd/elf32-arc.c
index d67e88c..2df91b1 100644
--- a/bfd/elf32-arc.c
+++ b/bfd/elf32-arc.c
@@ -26,6 +26,7 @@
 #include "elf/arc.h"
 #include "libiberty.h"
 #include "opcode/arc-func.h"
+#include "opcode/arc.h"
 #include "arc-plt.h"
 
 #ifdef DEBUG
@@ -722,6 +723,8 @@ struct arc_relocation_data
   bfd_signed_vma  got_symbol_vma;
 
   bfd_boolean	  should_relocate;
+
+  const char *    symbol_name;
 };
 
 static void
@@ -788,6 +791,52 @@ middle_endian_convert (bfd_vma insn, bfd_boolean do_it)
   return insn;
 }
 
+/* This function is called for relocations that are otherwise marked as NOT
+   requiring overflow checks.  In here we perform non-standard checks of
+   the relocation value.  */
+
+static inline bfd_reloc_status_type
+arc_special_overflow_checks (const struct arc_relocation_data reloc_data,
+                             bfd_signed_vma relocation,
+			     struct bfd_link_info *info ATTRIBUTE_UNUSED)
+{
+  switch (reloc_data.howto->type)
+    {
+    case R_ARC_NPS_CMEM16:
+      if (((relocation >> 16) & 0xffff) != NPS_CMEM_HIGH_VALUE)
+        {
+          if (reloc_data.reloc_addend == 0)
+            (*_bfd_error_handler)
+              (_("%B(%A+0x%lx): CMEM relocation to `%s' is invalid, "
+                 "16 MSB should be 0x%04x (value is 0x%lx)"),
+               reloc_data.input_section->owner,
+               reloc_data.input_section,
+               reloc_data.reloc_offset,
+               reloc_data.symbol_name,
+               NPS_CMEM_HIGH_VALUE,
+               (relocation));
+          else
+            (*_bfd_error_handler)
+              (_("%B(%A+0x%lx): CMEM relocation to `%s+0x%lx' is invalid, "
+                 "16 MSB should be 0x%04x (value is 0x%lx)"),
+               reloc_data.input_section->owner,
+               reloc_data.input_section,
+               reloc_data.reloc_offset,
+               reloc_data.symbol_name,
+               reloc_data.reloc_addend,
+               NPS_CMEM_HIGH_VALUE,
+               (relocation));
+          return bfd_reloc_overflow;
+        }
+      break;
+
+    default:
+      break;
+    }
+
+  return bfd_reloc_ok;
+}
+
 #define ME(reloc) (reloc)
 
 #define IS_ME(FORMULA,BFD) ((strstr (FORMULA, "ME") != NULL) \
@@ -896,6 +945,7 @@ arc_do_relocation (bfd_byte * contents,
   bfd_vma orig_insn ATTRIBUTE_UNUSED;
   bfd * abfd = reloc_data.input_section->owner;
   struct elf_link_hash_table *htab ATTRIBUTE_UNUSED = elf_hash_table (info);
+  bfd_reloc_status_type flag;
 
   if (reloc_data.should_relocate == FALSE)
     return bfd_reloc_ok;
@@ -936,34 +986,34 @@ arc_do_relocation (bfd_byte * contents,
 
   /* Check for relocation overflow.  */
   if (reloc_data.howto->complain_on_overflow != complain_overflow_dont)
-    {
-      bfd_reloc_status_type flag;
-      flag = bfd_check_overflow (reloc_data.howto->complain_on_overflow,
-				 reloc_data.howto->bitsize,
-				 reloc_data.howto->rightshift,
-				 bfd_arch_bits_per_address (abfd),
-				 relocation);
+    flag = bfd_check_overflow (reloc_data.howto->complain_on_overflow,
+                               reloc_data.howto->bitsize,
+                               reloc_data.howto->rightshift,
+                               bfd_arch_bits_per_address (abfd),
+                               relocation);
+  else
+    flag = arc_special_overflow_checks (reloc_data, relocation, info);
 
 #undef  DEBUG_ARC_RELOC
 #define DEBUG_ARC_RELOC(A) debug_arc_reloc (A)
-      if (flag != bfd_reloc_ok)
-	{
-	  PR_DEBUG ( "Relocation overflows !!!!\n");
+  if (flag != bfd_reloc_ok)
+    {
+      PR_DEBUG ( "Relocation overflows !!!!\n");
 
-	  DEBUG_ARC_RELOC (reloc_data);
+      DEBUG_ARC_RELOC (reloc_data);
 
-	  PR_DEBUG (
-		  "Relocation value = signed -> %d, unsigned -> %u"
-		  ", hex -> (0x%08x)\n",
-		  (int) relocation,
-		  (unsigned int) relocation,
-		  (unsigned int) relocation);
-	  return flag;
-	}
+      PR_DEBUG (
+                "Relocation value = signed -> %d, unsigned -> %u"
+                ", hex -> (0x%08x)\n",
+                (int) relocation,
+                (unsigned int) relocation,
+                (unsigned int) relocation);
+      return flag;
     }
 #undef  DEBUG_ARC_RELOC
 #define DEBUG_ARC_RELOC(A)
 
+  /* Write updated instruction back to memory.  */
   switch (reloc_data.howto->size)
     {
       case 2:
@@ -1168,6 +1218,10 @@ elf_arc_relocate_section (bfd *		   output_bfd,
 
 	  reloc_data.sym_value = sym->st_value;
 	  reloc_data.sym_section = sec;
+	  reloc_data.symbol_name =
+            bfd_elf_string_from_elf_section (input_bfd,
+                                             symtab_hdr->sh_link,
+                                             sym->st_name);
 
 	  /* Mergeable section handling.  */
 	  if ((sec->flags & SEC_MERGE)
@@ -1284,6 +1338,7 @@ elf_arc_relocate_section (bfd *		   output_bfd,
 	    h = (struct elf_link_hash_entry *) h->root.u.i.link;
 
 	  BFD_ASSERT ((h->dynindx == -1) >= (h->forced_local != 0));
+	  reloc_data.symbol_name = h->root.root.string;
 	  /* If we have encountered a definition for this symbol.  */
 	  if (h->root.type == bfd_link_hash_defined
 	      || h->root.type == bfd_link_hash_defweak)