RISC-V: Move disassembler private data initialization

Because disassemble_info.private_data could be used not only by
riscv_disassemble_insn, this commit splits the initialization of the
private data to a separate function.

This commit now allows storing mapping symbol and/or section-related
information to riscv_private_data.

In performance perspective, it also has a penalty.  However, it can be
easily paid back by other optimizations and it makes implementing
some optimizations easier.

opcodes/ChangeLog:

	* riscv-dis.c (init_riscv_dis_private_data): New.
	(riscv_disassemble_insn): Move private data initialization to
	init_riscv_dis_private_data.
	(print_insn_riscv): Start initializing the private data
	instead of instruction only riscv_disassemble_insn function.

opcodes/riscv-dis.c

@@ -219,6 +219,29 @@ init_riscv_dis_state_for_arch_and_options (void)
   is_arch_changed = false;
 }
 
+/* Initialize private data of the disassemble_info.  */
+
+static void
+init_riscv_dis_private_data (struct disassemble_info *info)
+{
+  struct riscv_private_data *pd;
+
+  pd = info->private_data = xcalloc (1, sizeof (struct riscv_private_data));
+  pd->gp = 0;
+  pd->print_addr = 0;
+  for (int i = 0; i < (int)ARRAY_SIZE (pd->hi_addr); i++)
+    pd->hi_addr[i] = -1;
+  pd->to_print_addr = false;
+  pd->has_gp = false;
+
+  for (int i = 0; i < info->symtab_size; i++)
+    if (strcmp (bfd_asymbol_name (info->symtab[i]), RISCV_GP_SYMBOL) == 0)
+      {
+	pd->gp = bfd_asymbol_value (info->symtab[i]);
+	pd->has_gp = true;
+      }
+}
+
 /* Update architecture for disassembler with its context.
    Call initialization functions if either:
    -  the architecture for current context is changed or
@@ -806,7 +829,7 @@ riscv_disassemble_insn (bfd_vma memaddr, insn_t word, disassemble_info *info)
   const struct riscv_opcode *op, *matched_op;
   static bool init = false;
   static const struct riscv_opcode *riscv_hash[OP_MASK_OP + 1];
-  struct riscv_private_data *pd;
+  struct riscv_private_data *pd = info->private_data;
   int insnlen;
 
 #define OP_HASH_IDX(i) ((i) & (riscv_insn_length (i) == 2 ? 0x3 : OP_MASK_OP))
@@ -821,28 +844,6 @@ riscv_disassemble_insn (bfd_vma memaddr, insn_t word, disassemble_info *info)
       init = true;
     }
 
-  if (info->private_data == NULL)
-    {
-      int i;
-
-      pd = info->private_data = xcalloc (1, sizeof (struct riscv_private_data));
-      pd->gp = 0;
-      pd->print_addr = 0;
-      for (i = 0; i < (int)ARRAY_SIZE (pd->hi_addr); i++)
-	pd->hi_addr[i] = -1;
-      pd->to_print_addr = false;
-      pd->has_gp = false;
-
-      for (i = 0; i < info->symtab_size; i++)
-	if (strcmp (bfd_asymbol_name (info->symtab[i]), RISCV_GP_SYMBOL) == 0)
-	  {
-	    pd->gp = bfd_asymbol_value (info->symtab[i]);
-	    pd->has_gp = true;
-	  }
-    }
-  else
-    pd = info->private_data;
-
   insnlen = riscv_insn_length (word);
 
   /* RISC-V instructions are always little-endian.  */
@@ -1215,6 +1216,10 @@ print_insn_riscv (bfd_vma memaddr, struct disassemble_info *info)
   enum riscv_seg_mstate mstate;
   int (*riscv_disassembler) (bfd_vma, insn_t, struct disassemble_info *);
 
+  /* Initialize the private data.  */
+  if (info->private_data == NULL)
+    init_riscv_dis_private_data (info);
+
   /* Guess and update XLEN if we haven't determined it yet.  */
   if (xlen == 0)
     update_riscv_dis_xlen (info);