Add support for 64-bit ARM architecture: AArch64

1 files changed, 1317 insertions, 0 deletions

diff --git a/opcodes/aarch64-gen.c b/opcodes/aarch64-gen.c
new file mode 100644
index 0000000..95bd016
--- /dev/null
+++ b/opcodes/aarch64-gen.c
@@ -0,0 +1,1317 @@
+/* aarch64-gen.c -- Generate tables and routines for opcode lookup and
+   instruction encoding and decoding.
+   Copyright 2012  Free Software Foundation, Inc.
+   Contributed by ARM Ltd.
+
+   This file is part of the GNU opcodes library.
+
+   This library is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   It is distributed in the hope that it will be useful, but WITHOUT
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+   License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; see the file COPYING3. If not,
+   see <http://www.gnu.org/licenses/>.  */
+
+#include "sysdep.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+#include "libiberty.h"
+#include "getopt.h"
+#include "opcode/aarch64.h"
+
+#include "aarch64-tbl.h"
+
+static int debug = 0;
+
+/* Structure used in the decoding tree to group a list of aarch64_opcode
+   entries.  */
+
+struct opcode_node
+{
+  aarch64_insn opcode;
+  aarch64_insn mask;
+  /* Index of the entry in the original table; the top 2 bits help
+     determine the table.  */
+  unsigned int index;
+  struct opcode_node *next;
+};
+
+typedef struct opcode_node opcode_node;
+
+/* Head of the list of the opcode_node after read_table.  */
+static opcode_node opcode_nodes_head;
+
+/* Node in the decoding tree.  */
+
+struct bittree
+{
+  unsigned int bitno;
+  /* 0, 1, and X (don't care).  */
+  struct bittree *bits[2];
+  /* List of opcodes; only valid for the leaf node.  */
+  opcode_node *list;
+};
+
+/* Allocate and initialize an opcode_node.  */
+static opcode_node*
+new_opcode_node (void)
+{
+  opcode_node* ent = malloc (sizeof (opcode_node));
+
+  if (!ent)
+    abort ();
+
+  ent->opcode = 0;
+  ent->mask = 0;
+  ent->index = -1;
+  ent->next = NULL;
+
+  return ent;
+}
+
+/* Multiple tables are supported, although currently only one table is
+   in use.  N.B. there are still some functions have the table name
+   'aarch64_opcode_table' hard-coded in, e.g. print_find_next_opcode;
+   therefore some amount of work needs to be done if the full support
+   for multiple tables needs to be enabled.  */
+static const struct aarch64_opcode *aarch64_opcode_tables[] =
+{aarch64_opcode_table};
+
+/* Use top 2 bits to indiate which table.  */
+static unsigned int
+initialize_index (const struct aarch64_opcode* table)
+{
+  int i;
+  const int num_of_tables = sizeof (aarch64_opcode_tables)
+    / sizeof (struct aarch64_opcode *);
+  for (i = 0; i < num_of_tables; ++i)
+    if (table == aarch64_opcode_tables [i])
+      break;
+  if (i == num_of_tables)
+    abort ();
+  return (unsigned int)i << 30;
+}
+
+static inline const struct aarch64_opcode *
+index2table (unsigned int index)
+{
+  return aarch64_opcode_tables[(index >> 30) & 0x3];
+}
+
+static inline unsigned int
+real_index (unsigned int index)
+{
+  return index & ((1 << 30) - 1);
+}
+
+/* Given OPCODE_NODE, return the corresponding aarch64_opcode*.  */
+static const aarch64_opcode*
+get_aarch64_opcode (const opcode_node *opcode_node)
+{
+  if (opcode_node == NULL)
+    return NULL;
+  return &index2table (opcode_node->index)[real_index (opcode_node->index)];
+}
+
+static void
+read_table (const struct aarch64_opcode* table)
+{
+  const struct aarch64_opcode *ent = table;
+  opcode_node **new_ent;
+  unsigned int index = initialize_index (table);
+
+  if (!ent->name)
+    return;
+
+  new_ent = &opcode_nodes_head.next;
+
+  while (*new_ent)
+    new_ent = &(*new_ent)->next;
+
+  do
+    {
+      /* F_PSEUDO needs to be used together with F_ALIAS to indicate an alias
+	 opcode is a programmer friendly pseudo instruction available only in
+	 the assembly code (thus will not show up in the disassembly).  */
+      assert (pseudo_opcode_p (ent) == FALSE || alias_opcode_p (ent) == TRUE);
+      /* Skip alias (inc. pseudo) opcode.  */
+      if (alias_opcode_p (ent) == TRUE)
+	{
+	  index++;
+	  continue;
+	}
+      *new_ent = new_opcode_node ();
+      (*new_ent)->opcode = ent->opcode;
+      (*new_ent)->mask = ent->mask;
+      (*new_ent)->index = index++;
+      new_ent = &((*new_ent)->next);
+    } while ((++ent)->name);
+}
+
+static inline void
+print_one_opcode_node (opcode_node* ent)
+{
+  printf ("%s\t%08x\t%08x\t%d\n", get_aarch64_opcode (ent)->name,
+	  get_aarch64_opcode (ent)->opcode, get_aarch64_opcode (ent)->mask,
+	  (int)real_index (ent->index));
+}
+
+/* As an internal debugging utility, print out the list of nodes pointed
+   by opcode_nodes_head.  */
+static void
+print_opcode_nodes (void)
+{
+  opcode_node* ent = opcode_nodes_head.next;
+  printf ("print_opcode_nodes table:\n");
+  while (ent)
+    {
+      print_one_opcode_node (ent);
+      ent = ent->next;
+    }
+}
+
+static struct bittree*
+new_bittree_node (void)
+{
+  struct bittree* node;
+  node = malloc (sizeof (struct bittree));
+  if (!node)
+    abort ();
+  node->bitno = -1;
+  node->bits[0] = NULL;
+  node->bits[1] = NULL;
+  return node;
+}
+
+/* The largest number of opcode entries that exist at a leaf node of the
+   decoding decision tree.  The reason that there can be more than one
+   opcode entry is because some opcodes have shared field that is partially
+   constrained and thus cannot be fully isolated using the algorithm
+   here.  */
+static int max_num_opcodes_at_leaf_node = 0;
+
+/* Given a list of opcodes headed by *OPCODE, try to establish one bit that
+   is shared by all the opcodes in the list as one of base opcode bits.  If
+   such a bit is found, divide the list of the opcodes into two based on the
+   value of the bit.
+
+   Store the bit number in BITTREE->BITNO if the division succeeds.  If unable
+   to determine such a bit or there is only one opcode in the list, the list
+   is decided to be undividable and OPCODE will be assigned to BITTREE->LIST.
+
+   The function recursively call itself until OPCODE is undividable.
+   
+   N.B. the nature of this algrithm determines that given any value in the
+   32-bit space, the computed decision tree will always be able to find one or
+   more opcodes entries for it, regardless whether there is a valid instruction
+   defined for this value or not.  In order to detect the undefined values,
+   when the caller obtains the opcode entry/entries, it should at least compare
+   the bit-wise AND result of the value and the mask with the base opcode
+   value; if the two are different, it means that the value is undefined
+   (although the value may be still undefined when the comparison is the same,
+   in which case call aarch64_opcode_decode to carry out further checks).  */
+
+static void
+divide_table_1 (struct bittree *bittree, opcode_node *opcode)
+{
+  aarch64_insn mask_and;
+  opcode_node *ent;
+  unsigned int bitno;
+  aarch64_insn bitmask;
+  opcode_node list0, list1, **ptr0, **ptr1;
+  static int depth = 0;
+
+  ++depth;
+
+  if (debug)
+    printf ("Enter into depth %d\n", depth);
+
+  assert (opcode != NULL);
+
+  /* Succeed when there is only one opcode left.  */
+  if (!opcode->next)
+    {
+      if (debug)
+	{
+	  printf ("opcode isolated:\n");
+	  print_one_opcode_node (opcode);
+	}
+      goto divide_table_1_finish;
+    }
+
+divide_table_1_try_again:
+  mask_and = -1;
+  ent = opcode;
+  while (ent)
+    {
+      mask_and &= ent->mask;
+      ent = ent->next;
+    }
+
+  if (debug)
+    printf ("mask and result: %08x\n", (unsigned int)mask_and);
+
+  /* If no more bit to look into, we have to accept the reality then.  */
+  if (!mask_and)
+    {
+      int i;
+      opcode_node *ptr;
+      if (debug)
+	{
+	  ptr = opcode;
+	  printf ("Isolated opcode group:\n");
+	  do {
+	      print_one_opcode_node (ptr);
+	      ptr = ptr->next;
+	  } while (ptr);
+	}
+      /* Count the number of opcodes.  */
+      for (i = 0, ptr = opcode; ptr; ++i)
+	ptr = ptr->next;
+      if (i > max_num_opcodes_at_leaf_node)
+	max_num_opcodes_at_leaf_node = i;
+      goto divide_table_1_finish;
+    }
+
+  /* Pick up the right most bit that is 1.  */
+  bitno = 0;
+  while (!(mask_and & (1 << bitno)))
+    ++bitno;
+  bitmask = (1 << bitno);
+
+  if (debug)
+    printf ("use bit %d\n", bitno);
+
+  /* Record in the bittree.  */
+  bittree->bitno = bitno;
+
+  /* Get two new opcode lists; adjust their masks.  */
+  list0.next = NULL;
+  list1.next = NULL;
+  ptr0 = &list0.next;
+  ptr1 = &list1.next;
+  ent = opcode;
+  while (ent)
+    {
+      if (ent->opcode & bitmask)
+	{
+	  ent->mask &= (~bitmask);
+	  *ptr1 = ent;
+	  ent = ent->next;
+	  (*ptr1)->next = NULL;
+	  ptr1 = &(*ptr1)->next;
+	}
+      else
+	{
+	  ent->mask &= (~bitmask);
+	  *ptr0 = ent;
+	  ent = ent->next;
+	  (*ptr0)->next = NULL;
+	  ptr0 = &(*ptr0)->next;
+	}
+    }
+
+  /* If BITNO can NOT divide the opcode group, try next bit.  */
+  if (list0.next == NULL)
+    {
+      opcode = list1.next;
+      goto divide_table_1_try_again;
+    }
+  else if (list1.next == NULL)
+    {
+      opcode = list0.next;
+      goto divide_table_1_try_again;
+    }
+
+  /* Further divide.  */
+  bittree->bits[0] = new_bittree_node ();
+  bittree->bits[1] = new_bittree_node ();
+  divide_table_1 (bittree->bits[0], list0.next);
+  divide_table_1 (bittree->bits[1], list1.next);
+
+divide_table_1_finish:
+  if (debug)
+    printf ("Leave from depth %d\n", depth);
+  --depth;
+
+  /* Record the opcode entries on this leaf node.  */
+  bittree->list = opcode;
+
+  return;
+}
+
+/* Call divide_table_1 to divide the all the opcodes and thus create the
+   decoding decision tree.  */
+static struct bittree *
+divide_table (void)
+{
+  struct bittree *bittree = new_bittree_node ();
+  divide_table_1 (bittree, opcode_nodes_head.next);
+  return bittree;
+}
+
+/* Read in all of the tables, create the decoding decision tree and return
+   the tree root.  */
+static struct bittree *
+initialize_decoder_tree (void)
+{
+  int i;
+  const int num_of_tables = (sizeof (aarch64_opcode_tables)
+			     / sizeof (struct aarch64_opcode *));
+  for (i = 0; i < num_of_tables; ++i)
+    read_table (aarch64_opcode_tables [i]);
+  if (debug)
+    print_opcode_nodes ();
+  return divide_table ();
+}
+
+static void __attribute__ ((format (printf, 2, 3)))
+indented_print (unsigned int indent, const char *format, ...)
+{
+  /* 80 number of spaces pluc a NULL terminator.  */
+  static const char spaces[81] =
+    "                                                                                ";
+  va_list ap;
+  va_start (ap, format);
+  assert (indent <= 80);
+  printf ("%s", &spaces[80 - indent]);
+  vprintf (format, ap);
+  va_end (ap);
+}
+
+/* N.B. read the comment above divide_table_1 for the reason why the generated
+   decision tree function never returns NULL.  */
+
+static void
+print_decision_tree_1 (unsigned int indent, struct bittree* bittree)
+{
+  /* PATTERN is only used to generate comment in the code.  */
+  static char pattern[33] = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
+  assert (bittree != NULL);
+
+  /* Leaf node located.  */
+  if (bittree->bits[0] == NULL && bittree->bits[1] == NULL)
+    {
+      assert (bittree->list != NULL);
+      indented_print (indent, "/* 33222222222211111111110000000000\n");
+      indented_print (indent, "   10987654321098765432109876543210\n");
+      indented_print (indent, "   %s\n", pattern);
+      indented_print (indent, "   %s.  */\n",
+		      get_aarch64_opcode (bittree->list)->name);
+      indented_print (indent, "return %u;\n",
+		      real_index (bittree->list->index));
+      return;
+    }
+
+  /* Walk down the decoder tree.  */
+  indented_print (indent, "if (((word >> %d) & 0x1) == 0)\n", bittree->bitno);
+  indented_print (indent, "  {\n");
+  pattern[bittree->bitno] = '0';
+  print_decision_tree_1 (indent + 4, bittree->bits[0]);
+  indented_print (indent, "  }\n");
+  indented_print (indent, "else\n");
+  indented_print (indent, "  {\n");
+  pattern[bittree->bitno] = '1';
+  print_decision_tree_1 (indent + 4, bittree->bits[1]);
+  indented_print (indent, "  }\n");
+  pattern[bittree->bitno] = 'x';
+}
+
+/* Generate aarch64_opcode_lookup in C code to the standard output.  */
+
+static void
+print_decision_tree (struct bittree* bittree)
+{
+  if (debug)
+    printf ("Enter print_decision_tree\n");
+
+  printf ("/* Called by aarch64_opcode_lookup.  */\n\n");
+
+  printf ("static int\n");
+  printf ("aarch64_opcode_lookup_1 (uint32_t word)\n");
+  printf ("{\n");
+
+  print_decision_tree_1 (2, bittree);
+
+  printf ("}\n\n");
+
+
+  printf ("/* Lookup opcode WORD in the opcode table.  N.B. all alias\n");
+  printf ("   opcodes are ignored here.  */\n\n");
+
+  printf ("const aarch64_opcode *\n");
+  printf ("aarch64_opcode_lookup (uint32_t word)\n");
+  printf ("{\n");
+  printf ("  return aarch64_opcode_table + aarch64_opcode_lookup_1 (word);\n");
+  printf ("}\n");
+}
+
+static void
+print_find_next_opcode_1 (struct bittree* bittree)
+{
+  assert (bittree != NULL);
+
+  /* Leaf node located.  */
+  if (bittree->bits[0] == NULL && bittree->bits[1] == NULL)
+    {
+      assert (bittree->list != NULL);
+      /* Find multiple opcode entries in one leaf node.  */
+      if (bittree->list->next != NULL)
+	{
+	  opcode_node *list = bittree->list;
+	  while (list != NULL)
+	    {
+	      const aarch64_opcode *curr = get_aarch64_opcode (list);
+	      const aarch64_opcode *next = get_aarch64_opcode (list->next);
+
+	      printf ("    case %u: ",
+		      (unsigned int)(curr - aarch64_opcode_table));
+	      if (list->next != NULL)
+		{
+		  printf ("value = %u; break;\t", real_index (list->next->index));
+		  printf ("/* %s --> %s.  */\n", curr->name, next->name);
+		}
+	      else
+		{
+		  printf ("return NULL;\t\t");
+		  printf ("/* %s --> NULL.  */\n", curr->name);
+		}
+
+	      list = list->next;
+	    }
+	}
+      return;
+    }
+
+  /* Walk down the decoder tree.  */
+  print_find_next_opcode_1 (bittree->bits[0]);
+  print_find_next_opcode_1 (bittree->bits[1]);
+}
+
+/* Generate aarch64_find_next_opcode in C code to the standard output.  */
+
+static void
+print_find_next_opcode (struct bittree* bittree)
+{
+  if (debug)
+    printf ("Enter print_find_next_opcode\n");
+
+  printf ("\n");
+  printf ("const aarch64_opcode *\n");
+  printf ("aarch64_find_next_opcode (const aarch64_opcode *opcode)\n");
+  printf ("{\n");
+  printf ("  /* Use the index as the key to locate the next opcode.  */\n");
+  printf ("  int key = opcode - aarch64_opcode_table;\n");
+  printf ("  int value;\n");
+  printf ("  switch (key)\n");
+  printf ("    {\n");
+
+  print_find_next_opcode_1 (bittree);
+
+  printf ("    default: return NULL;\n");
+  printf ("    }\n\n");
+
+  printf ("  return aarch64_opcode_table + value;\n");
+  printf ("}\n");
+}
+
+/* Release the dynamic memory resource allocated for the generation of the
+   decoder tree.  */
+
+static void
+release_resource_decoder_tree (struct bittree* bittree)
+{
+  assert (bittree != NULL);
+
+  /* Leaf node located.  */
+  if (bittree->bits[0] == NULL && bittree->bits[1] == NULL)
+    {
+      assert (bittree->list != NULL);
+      /* Free opcode_nodes.  */
+      opcode_node *list = bittree->list;
+      while (list != NULL)
+	{
+	  opcode_node *next = list->next;
+	  free (list);
+	  list = next;
+	}
+      /* Free the tree node.  */
+      free (bittree);
+      return;
+    }
+
+  /* Walk down the decoder tree.  */
+  release_resource_decoder_tree (bittree->bits[0]);
+  release_resource_decoder_tree (bittree->bits[1]);
+
+  /* Free the tree node.  */
+  free (bittree);
+}
+
+/* Generate aarch64_find_real_opcode in C code to the standard output.
+   TABLE points to the alias info table, while NUM indicates the number of
+   entries in the table.  */
+
+static void
+print_find_real_opcode (const opcode_node *table, int num)
+{
+  int i;
+
+  if (debug)
+    printf ("Enter print_find_real_opcode\n");
+
+  printf ("\n");
+  printf ("const aarch64_opcode *\n");
+  printf ("aarch64_find_real_opcode (const aarch64_opcode *opcode)\n");
+  printf ("{\n");
+  printf ("  /* Use the index as the key to locate the real opcode.  */\n");
+  printf ("  int key = opcode - aarch64_opcode_table;\n");
+  printf ("  int value;\n");
+  printf ("  switch (key)\n");
+  printf ("    {\n");
+
+  for (i = 0; i < num; ++i)
+    {
+      const opcode_node *real = table + i;
+      const opcode_node *alias = real->next;
+      for (; alias; alias = alias->next)
+	printf ("    case %u:\t/* %s */\n", real_index (alias->index),
+		get_aarch64_opcode (alias)->name);
+      printf ("      value = %u;\t/* --> %s.  */\n", real_index (real->index),
+	      get_aarch64_opcode (real)->name);
+      printf ("      break;\n");
+    }
+
+  printf ("    default: return NULL;\n");
+  printf ("    }\n\n");
+
+  printf ("  return aarch64_opcode_table + value;\n");
+  printf ("}\n");
+}
+
+/* Generate aarch64_find_alias_opcode in C code to the standard output.
+   TABLE points to the alias info table, while NUM indicates the number of
+   entries in the table.  */
+
+static void
+print_find_alias_opcode (const opcode_node *table, int num)
+{
+  int i;
+
+  if (debug)
+    printf ("Enter print_find_alias_opcode\n");
+
+  printf ("\n");
+  printf ("const aarch64_opcode *\n");
+  printf ("aarch64_find_alias_opcode (const aarch64_opcode *opcode)\n");
+  printf ("{\n");
+  printf ("  /* Use the index as the key to locate the alias opcode.  */\n");
+  printf ("  int key = opcode - aarch64_opcode_table;\n");
+  printf ("  int value;\n");
+  printf ("  switch (key)\n");
+  printf ("    {\n");
+
+  for (i = 0; i < num; ++i)
+    {
+      const opcode_node *node = table + i;
+      assert (node->next);
+      printf ("    case %u: value = %u; break;", real_index (node->index),
+	      real_index (node->next->index));
+      printf ("\t/* %s --> %s.  */\n", get_aarch64_opcode (node)->name,
+	      get_aarch64_opcode (node->next)->name);
+    }
+
+  printf ("    default: return NULL;\n");
+  printf ("    }\n\n");
+
+  printf ("  return aarch64_opcode_table + value;\n");
+  printf ("}\n");
+}
+
+/* Generate aarch64_find_next_alias_opcode in C code to the standard output.
+   TABLE points to the alias info table, while NUM indicates the number of
+   entries in the table.  */
+
+static void
+print_find_next_alias_opcode (const opcode_node *table, int num)
+{
+  int i;
+
+  if (debug)
+    printf ("Enter print_find_next_alias_opcode\n");
+
+  printf ("\n");
+  printf ("const aarch64_opcode *\n");
+  printf ("aarch64_find_next_alias_opcode (const aarch64_opcode *opcode)\n");
+  printf ("{\n");
+  printf ("  /* Use the index as the key to locate the next opcode.  */\n");
+  printf ("  int key = opcode - aarch64_opcode_table;\n");
+  printf ("  int value;\n");
+  printf ("  switch (key)\n");
+  printf ("    {\n");
+
+  for (i = 0; i < num; ++i)
+    {
+      const opcode_node *node = table + i;
+      assert (node->next);
+      if (node->next->next == NULL)
+	continue;
+      while (node->next->next)
+	{
+	  printf ("    case %u: value = %u; break;", real_index (node->next->index),
+		 real_index (node->next->next->index));
+	  printf ("\t/* %s --> %s.  */\n",
+		  get_aarch64_opcode (node->next)->name,
+		  get_aarch64_opcode (node->next->next)->name);
+	  node = node->next;
+	}
+    }
+
+  printf ("    default: return NULL;\n");
+  printf ("    }\n\n");
+
+  printf ("  return aarch64_opcode_table + value;\n");
+  printf ("}\n");
+}
+
+/* Given OPCODE, establish and return a link list of alias nodes in the
+   preferred order.  */
+
+opcode_node *
+find_alias_opcode (const aarch64_opcode *opcode)
+{
+  int i;
+  /* Assume maximum of 8 disassemble preference candidates.  */
+  const int max_num_aliases = 8;
+  const aarch64_opcode *ent;
+  const aarch64_opcode *preferred[max_num_aliases];
+  opcode_node head, **next;
+
+  assert (opcode_has_alias (opcode));
+
+  i = 0;
+  ent = aarch64_opcode_table;
+  while (ent->name != NULL)
+    {
+      /* The mask of an alias opcode must be equal to or a super-set (i.e.
+	 more constrained) of that of the aliased opcode; so is the base
+	 opcode value.  */
+      if (alias_opcode_p (ent) == TRUE
+	  && (ent->mask & opcode->mask) == opcode->mask
+	  && (opcode->mask & ent->opcode) == (opcode->mask & opcode->opcode))
+	{
+	  assert (i < max_num_aliases);
+	  preferred[i++] = ent;
+	  if (debug)
+	    printf ("found %s for %s.", ent->name, opcode->name);
+	}
+      ++ent;
+    }
+
+  if (debug)
+    {
+      int m;
+      printf ("un-orderd list: ");
+      for (m = 0; m < i; ++m)
+	printf ("%s, ", preferred[m]->name);
+      printf ("\n");
+    }
+
+  /* There must be at least one alias.  */
+  assert (i >= 1);
+
+  /* Sort preferred array according to the priority (from the lowest to the
+     highest.  */
+  if (i > 1)
+    {
+      int j, k;
+      for (j = 0; j < i - 1; ++j)
+	{
+	  for (k = 0; k < i - 1 - j; ++k)
+	    {
+	      const aarch64_opcode *t;
+	      t = preferred [k+1];
+	      if (opcode_priority (t) < opcode_priority (preferred [k]))
+		{
+		  preferred [k+1] = preferred [k];
+		  preferred [k] = t;
+		}
+	    }
+	}
+    }
+
+  if (debug)
+    {
+      int m;
+      printf ("orderd list: ");
+      for (m = 0; m < i; ++m)
+	printf ("%s, ", preferred[m]->name);
+      printf ("\n");
+    }
+
+  /* Create a link-list of opcode_node with disassemble preference from
+     higher to lower.  */
+  next = &head.next;
+  --i;
+  while (i >= 0)
+    {
+      const aarch64_opcode *alias = preferred [i];
+      opcode_node *node = new_opcode_node ();
+
+      if (debug)
+	printf ("add %s.\n", alias->name);
+
+      node->index = alias - aarch64_opcode_table;
+      *next = node;
+      next = &node->next;
+
+      --i;
+    }
+  *next = NULL;
+
+  return head.next;
+}
+
+/* Create and return alias information.
+   Return the address of the created alias info table; return the number
+   of table entries in *NUM_PTR.  */
+
+opcode_node *
+create_alias_info (int *num_ptr)
+{
+  int i, num;
+  opcode_node *ret;
+  const aarch64_opcode *ent;
+
+  /* Calculate the total number of opcodes that have alias.  */
+  num = 0;
+  ent = aarch64_opcode_table;
+  while (ent->name != NULL)
+    {
+      if (opcode_has_alias (ent))
+	{
+	  /* Assert the alias relationship be flat-structured to keep
+	     algorithms simple; not allow F_ALIAS and F_HAS_ALIAS both
+	     specified.  */
+	  assert (!alias_opcode_p (ent));
+	  ++num;
+	}
+      ++ent;
+    }
+  assert (num_ptr);
+  *num_ptr = num;
+
+  /* The array of real opcodes that have alias(es).  */
+  ret = malloc (sizeof (opcode_node) * num);
+
+  /* For each opcode, establish a list of alias nodes in a preferred
+     order.  */
+  for (i = 0, ent = aarch64_opcode_table; i < num; ++i, ++ent)
+    {
+      opcode_node *node = ret + i;
+      while (ent->name != NULL && !opcode_has_alias (ent))
+	++ent;
+      assert (ent->name != NULL);
+      node->index = ent - aarch64_opcode_table;
+      node->next = find_alias_opcode (ent);
+      assert (node->next);
+    }
+  assert (i == num);
+
+  return ret;
+}
+
+/* Release the dynamic memory resource allocated for the generation of the
+   alias information.  */
+
+void
+release_resource_alias_info (opcode_node *alias_info, int num)
+{
+  int i = 0;
+  opcode_node *node = alias_info;
+
+  /* Free opcode_node list.  */
+  for (; i < num; ++i, ++node)
+    {
+      opcode_node *list = node->next;
+      do
+	{
+	  opcode_node *next = list->next;
+	  free (list);
+	  list = next;
+	} while (list != NULL);
+    }
+
+  /* Free opcode_node array.  */
+  free (alias_info);
+}
+
+/* As a debugging utility, print out the result of the table division, although
+   it is not doing much this moment.  */
+static void
+print_divide_result (const struct bittree *bittree ATTRIBUTE_UNUSED)
+{
+  printf ("max_num_opcodes_at_leaf_node: %d\n", max_num_opcodes_at_leaf_node);
+  return;
+}
+
+/* Structure to help generate the operand table.  */
+struct operand
+{
+  const char *class;
+  const char *inserter;
+  const char *extractor;
+  const char *str;
+  const char *flags;
+  const char *fields;
+  const char *desc;
+  unsigned processed : 1;
+  unsigned has_inserter : 1;
+  unsigned has_extractor : 1;
+};
+
+typedef struct operand operand;
+
+#ifdef X
+#undef X
+#endif
+
+#ifdef Y
+#undef Y
+#endif
+
+#ifdef F
+#undef F
+#endif
+
+/* Get the operand information in strings.  */
+
+static operand operands[] =
+{
+    {"NIL", "0", "0", "", "0", "{0}", "<none>", 0, 0, 0},
+#define F(...)	#__VA_ARGS__
+#define X(a,b,c,d,e,f,g)	\
+    {#a, #b, #c, d, #e, "{"f"}", g, 0, 0, 0},
+#define Y(a,b,d,e,f,g)		\
+    {#a, "ins_"#b, "ext_"#b, d, #e, "{"f"}", g, 0, 0, 0},
+    AARCH64_OPERANDS
+    {"NIL", "0", "0", "", "0", "{0}", "DUMMY", 0, 0, 0},
+};
+
+#undef F
+#undef X
+
+static void
+process_operand_table (void)
+{
+  int i;
+  operand *opnd;
+  const int num = sizeof (operands) / sizeof (operand);
+
+  for (i = 0, opnd = operands; i < num; ++i, ++opnd)
+    {
+      opnd->has_inserter = opnd->inserter[0] != '0';
+      opnd->has_extractor = opnd->extractor[0] != '0';
+    }
+}
+
+/* Generate aarch64_operands in C to the standard output.  */
+
+static void
+print_operand_table (void)
+{
+  int i;
+  operand *opnd;
+  const int num = sizeof (operands) / sizeof (operand);
+
+  if (debug)
+    printf ("Enter print_operand_table\n");
+
+  printf ("\n");
+  printf ("const struct aarch64_operand aarch64_operands[] =\n");
+  printf ("{\n");
+
+  for (i = 0, opnd = operands; i < num; ++i, ++opnd)
+    {
+      char flags[256];
+      flags[0] = '\0';
+      if (opnd->flags[0] != '0')
+	sprintf (flags, "%s", opnd->flags);
+      if (opnd->has_inserter)
+	{
+	  if (flags[0] != '\0')
+	    strcat (flags, " | ");
+	  strcat (flags, "OPD_F_HAS_INSERTER");
+	}
+      if (opnd->has_extractor)
+	{
+	  if (flags[0] != '\0')
+	    strcat (flags, " | ");
+	  strcat (flags, "OPD_F_HAS_EXTRACTOR");
+	}
+      if (flags[0] == '\0')
+	{
+	  flags[0] = '0';
+	  flags[1] = '\0';
+	}
+    printf ("  {AARCH64_OPND_CLASS_%s, \"%s\", %s, %s, \"%s\"},\n",
+	    opnd->class, opnd->str, flags, opnd->fields, opnd->desc);
+    }
+  printf ("};\n");
+}
+
+/* Generate aarch64_insert_operand in C to the standard output.  */
+
+static void
+print_operand_inserter (void)
+{
+  int i;
+  operand *opnd;
+  const int num = sizeof (operands) / sizeof (operand);
+
+  if (debug)
+    printf ("Enter print_operand_inserter\n");
+
+  printf ("\n");
+  printf ("const char*\n");
+  printf ("aarch64_insert_operand (const aarch64_operand *self,\n\
+			   const aarch64_opnd_info *info,\n\
+			   aarch64_insn *code, const aarch64_inst *inst)\n");
+  printf ("{\n");
+  printf ("  /* Use the index as the key.  */\n");
+  printf ("  int key = self - aarch64_operands;\n");
+  printf ("  switch (key)\n");
+  printf ("    {\n");
+
+  for (i = 0, opnd = operands; i < num; ++i, ++opnd)
+    opnd->processed = 0;
+
+  for (i = 0, opnd = operands; i < num; ++i, ++opnd)
+    {
+      if (!opnd->processed && opnd->has_inserter)
+	{
+	  int j = i + 1;
+	  const int len = strlen (opnd->inserter);
+	  operand *opnd2 = opnd + 1;
+	  printf ("    case %u:\n", (unsigned int)(opnd - operands));
+	  opnd->processed = 1;
+	  for (; j < num; ++j, ++opnd2)
+	    {
+	      if (!opnd2->processed
+		  && opnd2->has_inserter
+		  && len == strlen (opnd2->inserter)
+		  && strncmp (opnd->inserter, opnd2->inserter, len) == 0)
+		{
+		  printf ("    case %u:\n", (unsigned int)(opnd2 - operands));
+		  opnd2->processed = 1;
+		}
+	    }
+	  printf ("      return aarch64_%s (self, info, code, inst);\n",
+		  opnd->inserter);
+	}
+    }
+
+  printf ("    default: assert (0); abort ();\n");
+  printf ("    }\n");
+  printf ("}\n");
+}
+
+/* Generate aarch64_extract_operand in C to the standard output.  */
+
+static void
+print_operand_extractor (void)
+{
+  int i;
+  operand *opnd;
+  const int num = sizeof (operands) / sizeof (operand);
+
+  if (debug)
+    printf ("Enter print_operand_extractor\n");
+
+  printf ("\n");
+  printf ("int\n");
+  printf ("aarch64_extract_operand (const aarch64_operand *self,\n\
+			   aarch64_opnd_info *info,\n\
+			   aarch64_insn code, const aarch64_inst *inst)\n");
+  printf ("{\n");
+  printf ("  /* Use the index as the key.  */\n");
+  printf ("  int key = self - aarch64_operands;\n");
+  printf ("  switch (key)\n");
+  printf ("    {\n");
+
+  for (i = 0, opnd = operands; i < num; ++i, ++opnd)
+    opnd->processed = 0;
+
+  for (i = 0, opnd = operands; i < num; ++i, ++opnd)
+    {
+      if (!opnd->processed && opnd->has_extractor)
+	{
+	  int j = i + 1;
+	  const int len = strlen (opnd->extractor);
+	  operand *opnd2 = opnd + 1;
+	  printf ("    case %u:\n", (unsigned int)(opnd - operands));
+	  opnd->processed = 1;
+	  for (; j < num; ++j, ++opnd2)
+	    {
+	      if (!opnd2->processed
+		  && opnd2->has_extractor
+		  && len == strlen (opnd2->extractor)
+		  && strncmp (opnd->extractor, opnd2->extractor, len) == 0)
+		{
+		  printf ("    case %u:\n", (unsigned int)(opnd2 - operands));
+		  opnd2->processed = 1;
+		}
+	    }
+	  printf ("      return aarch64_%s (self, info, code, inst);\n",
+		  opnd->extractor);
+	}
+    }
+
+  printf ("    default: assert (0); abort ();\n");
+  printf ("    }\n");
+  printf ("}\n");
+}
+
+/* Table indexed by opcode enumerator stores the index of the corresponding
+   opcode entry in aarch64_opcode_table.  */
+static unsigned op_enum_table [OP_TOTAL_NUM];
+
+/* Print out the routine which, given the opcode enumerator, returns the
+   corresponding opcode entry pointer.  */
+
+static void
+print_get_opcode (void)
+{
+  int i;
+  const int num = OP_TOTAL_NUM;
+  const aarch64_opcode *opcode;
+
+  if (debug)
+    printf ("Enter print_get_opcode\n");
+
+  /* Fill in the internal table.  */
+  opcode = aarch64_opcode_table;
+  while (opcode->name != NULL)
+    {
+      if (opcode->op != OP_NIL)
+	{
+	  /* Assert opcode enumerator be unique, in other words, no shared by
+	     different opcodes.  */
+	  if (op_enum_table[opcode->op] != 0)
+	    {
+	      fprintf (stderr, "Opcode %u is shared by different %s and %s.\n",
+		       opcode->op,
+		       aarch64_opcode_table[op_enum_table[opcode->op]].name,
+		       opcode->name);
+	      assert (0);
+	      abort ();
+	    }
+	  assert (opcode->op < OP_TOTAL_NUM);
+	  op_enum_table[opcode->op] = opcode - aarch64_opcode_table;
+	}
+      ++opcode;
+    }
+
+  /* Print the table.  */
+  printf ("\n");
+  printf ("/* Indexed by an enum aarch64_op enumerator, the value is the offset of\n\
+   the corresponding aarch64_opcode entry in the aarch64_opcode_table.  */\n\n");
+  printf ("static const unsigned op_enum_table [] =\n");
+  printf ("{\n");
+  for (i = 0; i < num; ++i)
+    printf ("  %u,\n", op_enum_table[i]);
+  printf ("};\n");
+
+  /* Print the function.  */
+  printf ("\n");
+  printf ("/* Given the opcode enumerator OP, return the pointer to the corresponding\n");
+  printf ("   opcode entry.  */\n");
+  printf ("\n");
+  printf ("const aarch64_opcode *\n");
+  printf ("aarch64_get_opcode (enum aarch64_op op)\n");
+  printf ("{\n");
+  printf ("  return aarch64_opcode_table + op_enum_table[op];\n");
+  printf ("}\n");
+}
+
+/* Print out the content of an opcode table (not in use).  */
+static void ATTRIBUTE_UNUSED
+print_table (struct aarch64_opcode* table)
+{
+  struct aarch64_opcode *ent = table;
+  do
+    {
+      printf ("%s\t%08x\t%08x\n", ent->name, (unsigned int)ent->opcode,
+	      (unsigned int)ent->mask);
+    } while ((++ent)->name);
+}
+
+static const char * program_name = NULL;
+
+/* Program options.  */
+struct option long_options[] =
+{
+  {"debug",   no_argument,       NULL, 'd'},
+  {"version", no_argument,       NULL, 'V'},
+  {"help",    no_argument,       NULL, 'h'},
+  {"gen-opc", no_argument,       NULL, 'c'},
+  {"gen-asm", no_argument,       NULL, 'a'},
+  {"gen-dis", no_argument,       NULL, 's'},
+  {0,         no_argument,       NULL, 0}
+};
+
+static void
+print_version (void)
+{
+  printf ("%s: version 1.0\n", program_name);
+  xexit (0);
+}
+
+static void
+usage (FILE * stream, int status)
+{
+  fprintf (stream, "Usage: %s [-V | --version] [-d | --debug] [--help]\n",
+	   program_name);
+  fprintf (stream, "\t[ [-c | --gen-opc] | [-a | --gen-asm] | [-s | --gen-dis] ]\n");
+  xexit (status);
+}
+
+int
+main (int argc, char **argv)
+{
+  extern int chdir (char *);
+  int c;
+  int gen_opcode_p = 0;
+  int gen_assembler_p = 0;
+  int gen_disassembler_p = 0;
+
+  program_name = *argv;
+  xmalloc_set_program_name (program_name);
+
+  while ((c = getopt_long (argc, argv, "vVdhacs", long_options, 0)) != EOF)
+    switch (c)
+      {
+      case 'V':
+      case 'v':
+	print_version ();
+	break;
+      case 'd':
+	debug = 1;
+	break;
+      case 'h':
+      case '?':
+	usage (stderr, 0);
+	break;
+      case 'c':
+	gen_opcode_p = 1;
+	break;
+      case 'a':
+	gen_assembler_p = 1;
+	break;
+      case 's':
+	gen_disassembler_p = 1;
+	break;
+      default:
+      case 0:
+	break;
+      }
+
+  if (argc == 1 || optind != argc)
+    usage (stdout, 1);
+
+  if (gen_opcode_p + gen_assembler_p + gen_disassembler_p > 1)
+    {
+      printf ("Please specify only one of the following options\n\
+	      [-c | --gen-opc] [-a | --gen-asm] [-s | --gen-dis]\n");
+      xexit (2);
+    }
+
+  struct bittree *decoder_tree;
+
+  decoder_tree = initialize_decoder_tree ();
+  if (debug)
+    print_divide_result (decoder_tree);
+
+  printf ("/* This file is automatically generated by aarch64-gen.  Do not edit!  */\n");
+  printf ("/* Copyright 2012  Free Software Foundation, Inc.\n\
+   Contributed by ARM Ltd.\n\
+\n\
+   This file is part of the GNU opcodes library.\n\
+\n\
+   This library is free software; you can redistribute it and/or modify\n\
+   it under the terms of the GNU General Public License as published by\n\
+   the Free Software Foundation; either version 3, or (at your option)\n\
+   any later version.\n\
+\n\
+   It is distributed in the hope that it will be useful, but WITHOUT\n\
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY\n\
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public\n\
+   License for more details.\n\
+\n\
+   You should have received a copy of the GNU General Public License\n\
+   along with this program; see the file COPYING3. If not,\n\
+   see <http://www.gnu.org/licenses/>.  */\n");
+
+  printf ("\n");
+  printf ("#include \"sysdep.h\"\n");
+  if (gen_opcode_p)
+    printf ("#include \"aarch64-opc.h\"\n");
+  if (gen_assembler_p)
+    printf ("#include \"aarch64-asm.h\"\n");
+  if (gen_disassembler_p)
+    printf ("#include \"aarch64-dis.h\"\n");
+  printf ("\n");
+
+  /* Generate opcode entry lookup for the disassembler.  */
+  if (gen_disassembler_p)
+    {
+      print_decision_tree (decoder_tree);
+      print_find_next_opcode (decoder_tree);
+      release_resource_decoder_tree (decoder_tree);
+    }
+
+  /* Generate alias opcode handling for the assembler or the disassembler.  */
+  if (gen_assembler_p || gen_disassembler_p)
+    {
+      int num;
+      opcode_node *alias_info = create_alias_info (&num);
+
+      if (gen_assembler_p)
+	print_find_real_opcode (alias_info, num);
+
+      if (gen_disassembler_p)
+	{
+	  print_find_alias_opcode (alias_info, num);
+	  print_find_next_alias_opcode (alias_info, num);
+	}
+
+      release_resource_alias_info (alias_info, num);
+    }
+
+  /* Generate operand table.  */
+  process_operand_table ();
+
+  if (gen_assembler_p)
+    print_operand_inserter ();
+
+  if (gen_disassembler_p)
+    print_operand_extractor ();
+
+  if (gen_opcode_p)
+    print_operand_table ();
+
+  /* Generate utility to return aarch64_opcode entry given an enumerator.  */
+  if (gen_opcode_p)
+    print_get_opcode ();
+
+  exit (0);
+}