DesCGENization of the BPF binutils port

CGEN is cool, but the BPF architecture is simply too bizarre for it.

The weird way of BPF to handle endianness in instruction encoding, the
weird C-like alternative assembly syntax, the weird abuse of
multi-byte (or infra-byte) instruction fields as opcodes, the unusual
presence of opcodes beyond the first 32-bits of some instructions, are
all examples of what makes it a PITA to continue using CGEN for this
port.  The bpf.cpu file is becoming so complex and so nested with
p-macros that it is very difficult to read, and quite challenging to
update.  Also, every time we are forced to change something in CGEN to
accommodate BPF requirements (which is often) we have to do extensive
testing to make sure we do not break any other target using CGEN.

This is getting un-maintenable.

So I have decided to bite the bullet and revamp/rewrite the port so it
no longer uses CGEN.  Overall, this involved:

* To remove the cpu/bpf.{cpu,opc} descriptions.

* To remove the CGEN generated files.

* To replace the CGEN generated opcodes table with a new hand-written
  opcodes table for BPF.

* To replace the CGEN generated disassembler wih a new disassembler
  that uses the new opcodes.

* To replace the CGEN generated assembler with a new assembler that uses the
  new opcodes.

* To replace the CGEN generated simulator with a new simulator that uses the
  new opcodes. [This is pushed in GDB in another patch.]

* To adapt the build systems to the new situation.

Additionally, this patch introduces some extensions and improvements:

* A new BPF relocation BPF_RELOC_BPF_DISP16 plus corresponding ELF
  relocation R_BPF_GNU_64_16 are added to the BPF BFD port.  These
  relocations are used for section-relative 16-bit offsets used in
  load/store instructions.

* The disassembler now has support for the "pseudo-c" assembly syntax of
  BPF.  What dialect to use when disassembling is controlled by a command
  line option.

* The disassembler now has support for dumping instruction immediates in
  either octal, hexadecimal or decimal.  The used output base is controlled
  by a new command-line option.

* The GAS BPF test suite has been re-structured and expanded in order to
  test the disassembler pseudoc syntax support.  Minor bugs have been also
  fixed there.  The assembler generic tests that were disabled for bpf-*-*
  targets due to the previous implementation of pseudoc syntax are now
  re-enabled.  Additional tests have been added to test the new features of
  the assembler.  .dump files are no longer used.

* The linker BPF test suite has been adapted to the command line options
  used by the new disassembler.

The result is very satisfactory.  This patchs adds 3448 lines of code
and removes 10542 lines of code.

Tested in:

* Target bpf-unknown-none with 64-bit little-endian host and 32-bit
  little-endian host.

* Target x86-64-linux-gnu with --enable-targets=all

Note that I have not tested in a big-endian host yet.  I will do so
once this lands upstream so I can use the GCC compiler farm.

I have not included ChangeLog entries in this patch: these would be
massive and not very useful, considering this is pretty much a rewrite
of the port.  I beg the indulgence of the global maintainers.

1 files changed, 224 insertions, 571 deletions

diff --git a/opcodes/bpf-dis.c b/opcodes/bpf-dis.c
index 0a34517..a4dc3dc 100644
--- a/opcodes/bpf-dis.c
+++ b/opcodes/bpf-dis.c
@@ -1,631 +1,284 @@
-/* DO NOT EDIT!  -*- buffer-read-only: t -*- vi:set ro:  */
-/* Disassembler interface for targets using CGEN. -*- C -*-
-   CGEN: Cpu tools GENerator
+/* bpf-dis.c - BPF disassembler.
+   Copyright (C) 2023 Free Software Foundation, Inc.
 
-   THIS FILE IS MACHINE GENERATED WITH CGEN.
-   - the resultant file is machine generated, cgen-dis.in isn't
+   Contributed by Oracle Inc.
 
-   Copyright (C) 1996-2023 Free Software Foundation, Inc.
+   This file is part of the GNU binutils.
 
-   This file is part of libopcodes.
-
-   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
+   This is free software; you can redistribute them and/or modify them
+   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.
+   This program 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; if not, write to the Free Software Foundation, Inc.,
-   51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
-
-/* ??? Eventually more and more of this stuff can go to cpu-independent files.
-   Keep that in mind.  */
+   along with this program; see the file COPYING3. If not,
+   see <http://www.gnu.org/licenses/>.  */
 
 #include "sysdep.h"
-#include <stdio.h>
-#include "ansidecl.h"
 #include "disassemble.h"
-#include "bfd.h"
-#include "symcat.h"
 #include "libiberty.h"
-#include "bpf-desc.h"
-#include "bpf-opc.h"
 #include "opintl.h"
+#include "opcode/bpf.h"
 
-/* Default text to print if an instruction isn't recognized.  */
-#define UNKNOWN_INSN_MSG _("*unknown*")
-
-static void print_normal
-  (CGEN_CPU_DESC, void *, long, unsigned int, bfd_vma, int);
-static void print_address
-  (CGEN_CPU_DESC, void *, bfd_vma, unsigned int, bfd_vma, int) ATTRIBUTE_UNUSED;
-static void print_keyword
-  (CGEN_CPU_DESC, void *, CGEN_KEYWORD *, long, unsigned int) ATTRIBUTE_UNUSED;
-static void print_insn_normal
-  (CGEN_CPU_DESC, void *, const CGEN_INSN *, CGEN_FIELDS *, bfd_vma, int);
-static int print_insn
-  (CGEN_CPU_DESC, bfd_vma,  disassemble_info *, bfd_byte *, unsigned);
-static int default_print_insn
-  (CGEN_CPU_DESC, bfd_vma, disassemble_info *) ATTRIBUTE_UNUSED;
-static int read_insn
-  (CGEN_CPU_DESC, bfd_vma, disassemble_info *, bfd_byte *, int, CGEN_EXTRACT_INFO *,
-   unsigned long *);
-
-/* -- disassembler routines inserted here.  */
-
-/* -- dis.c */
-
-/* We need to customize the disassembler a bit:
-   - Use 8 bytes per line by default.
-*/
-
-#define CGEN_PRINT_INSN bpf_print_insn
-
-static int
-bpf_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
-{
-  bfd_byte buf[CGEN_MAX_INSN_SIZE];
-  int buflen;
-  int status;
-
-  info->bytes_per_chunk = 1;
-  info->bytes_per_line = 8;
-
-  /* Attempt to read the base part of the insn.  */
-  buflen = cd->base_insn_bitsize / 8;
-  status = (*info->read_memory_func) (pc, buf, buflen, info);
-
-  /* Try again with the minimum part, if min < base.  */
-  if (status != 0 && (cd->min_insn_bitsize < cd->base_insn_bitsize))
-    {
-      buflen = cd->min_insn_bitsize / 8;
-      status = (*info->read_memory_func) (pc, buf, buflen, info);
-    }
-
-  if (status != 0)
-    {
-      (*info->memory_error_func) (status, pc, info);
-      return -1;
-    }
-
-  return print_insn (cd, pc, info, buf, buflen);
-}
+#include <string.h>
+#include <inttypes.h>
 
-/* Signed immediates should be printed in hexadecimal.  */
+/* This disassembler supports two different syntaxes for BPF assembly.
+   One is called "normal" and has the typical form for assembly
+   languages, with mnemonics and the like.  The othe is called
+   "pseudoc" and looks like C.  */
 
-static void
-print_immediate (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
-                 void *dis_info,
-                 int64_t value,
-                 unsigned int attrs ATTRIBUTE_UNUSED,
-                 bfd_vma pc ATTRIBUTE_UNUSED,
-                 int length ATTRIBUTE_UNUSED)
+enum bpf_dialect
 {
-  disassemble_info *info = (disassemble_info *) dis_info;
-
-  if (value <= 9)
-    (*info->fprintf_func) (info->stream, "%" PRId64, value);
-  else
-    (*info->fprintf_func) (info->stream, "%#" PRIx64, value);
-
-  /* This is to avoid -Wunused-function for print_normal.  */
-  if (0)
-    print_normal (cd, dis_info, value, attrs, pc, length);
-}
-
-/* Endianness bit sizes should be printed in decimal.  */
-
-static void
-print_endsize (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
-               void *dis_info,
-               unsigned long value,
-               unsigned int attrs ATTRIBUTE_UNUSED,
-               bfd_vma pc ATTRIBUTE_UNUSED,
-               int length ATTRIBUTE_UNUSED)
-{
-  disassemble_info *info = (disassemble_info *) dis_info;
-  (*info->fprintf_func) (info->stream, "%lu", value);
-}
-
-
-/* -- */
-
-void bpf_cgen_print_operand
-  (CGEN_CPU_DESC, int, void *, CGEN_FIELDS *, void const *, bfd_vma, int);
+  BPF_DIALECT_NORMAL,
+  BPF_DIALECT_PSEUDOC
+};
 
-/* Main entry point for printing operands.
-   XINFO is a `void *' and not a `disassemble_info *' to not put a requirement
-   of dis-asm.h on cgen.h.
+/* Global configuration for the disassembler.  */
 
-   This function is basically just a big switch statement.  Earlier versions
-   used tables to look up the function to use, but
-   - if the table contains both assembler and disassembler functions then
-     the disassembler contains much of the assembler and vice-versa,
-   - there's a lot of inlining possibilities as things grow,
-   - using a switch statement avoids the function call overhead.
+static enum bpf_dialect asm_dialect = BPF_DIALECT_NORMAL;
+static int asm_bpf_version = BPF_V4;
+static int asm_obase = 10;
 
-   This function could be moved into `print_insn_normal', but keeping it
-   separate makes clear the interface between `print_insn_normal' and each of
-   the handlers.  */
+/* Print BPF specific command-line options.  */
 
 void
-bpf_cgen_print_operand (CGEN_CPU_DESC cd,
-			   int opindex,
-			   void * xinfo,
-			   CGEN_FIELDS *fields,
-			   void const *attrs ATTRIBUTE_UNUSED,
-			   bfd_vma pc,
-			   int length)
+print_bpf_disassembler_options (FILE *stream)
 {
-  disassemble_info *info = (disassemble_info *) xinfo;
-
-  switch (opindex)
-    {
-    case BPF_OPERAND_DISP16 :
-      print_normal (cd, info, fields->f_offset16, 0|(1<<CGEN_OPERAND_SIGNED)|(1<<CGEN_OPERAND_PCREL_ADDR), pc, length);
-      break;
-    case BPF_OPERAND_DISP32 :
-      print_normal (cd, info, fields->f_imm32, 0|(1<<CGEN_OPERAND_SIGNED)|(1<<CGEN_OPERAND_PCREL_ADDR), pc, length);
-      break;
-    case BPF_OPERAND_DSTBE :
-      print_keyword (cd, info, & bpf_cgen_opval_h_gpr, fields->f_dstbe, 0);
-      break;
-    case BPF_OPERAND_DSTLE :
-      print_keyword (cd, info, & bpf_cgen_opval_h_gpr, fields->f_dstle, 0);
-      break;
-    case BPF_OPERAND_ENDSIZE :
-      print_endsize (cd, info, fields->f_imm32, 0, pc, length);
-      break;
-    case BPF_OPERAND_IMM32 :
-      print_immediate (cd, info, fields->f_imm32, 0|(1<<CGEN_OPERAND_SIGNED), pc, length);
-      break;
-    case BPF_OPERAND_IMM64 :
-      print_immediate (cd, info, fields->f_imm64, 0|(1<<CGEN_OPERAND_SIGNED)|(1<<CGEN_OPERAND_VIRTUAL), pc, length);
-      break;
-    case BPF_OPERAND_OFFSET16 :
-      print_immediate (cd, info, fields->f_offset16, 0|(1<<CGEN_OPERAND_SIGNED), pc, length);
-      break;
-    case BPF_OPERAND_SRCBE :
-      print_keyword (cd, info, & bpf_cgen_opval_h_gpr, fields->f_srcbe, 0);
-      break;
-    case BPF_OPERAND_SRCLE :
-      print_keyword (cd, info, & bpf_cgen_opval_h_gpr, fields->f_srcle, 0);
-      break;
-
-    default :
-      /* xgettext:c-format */
-      opcodes_error_handler
-	(_("internal error: unrecognized field %d while printing insn"),
-	 opindex);
-      abort ();
-  }
+  fprintf (stream, _("\n\
+The following BPF specific disassembler options are supported for use\n\
+with the -M switch (multiple options should be separated by commas):\n"));
+  fprintf (stream, "\n");
+  fprintf (stream, _("\
+      pseudoc                  Use pseudo-c syntax.\n\
+      v1,v2,v3,v4,xbpf         Version of the BPF ISA to use.\n\
+      hex,oct,dec              Output numerical base for immediates.\n"));
 }
 
-cgen_print_fn * const bpf_cgen_print_handlers[] =
-{
-  print_insn_normal,
-};
-
-
-void
-bpf_cgen_init_dis (CGEN_CPU_DESC cd)
-{
-  bpf_cgen_init_opcode_table (cd);
-  bpf_cgen_init_ibld_table (cd);
-  cd->print_handlers = & bpf_cgen_print_handlers[0];
-  cd->print_operand = bpf_cgen_print_operand;
-}
-
-
-/* Default print handler.  */
+/* Parse BPF specific command-line options.  */
 
 static void
-print_normal (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
-	      void *dis_info,
-	      long value,
-	      unsigned int attrs,
-	      bfd_vma pc ATTRIBUTE_UNUSED,
-	      int length ATTRIBUTE_UNUSED)
+parse_bpf_dis_option (const char *option)
 {
-  disassemble_info *info = (disassemble_info *) dis_info;
-
-  /* Print the operand as directed by the attributes.  */
-  if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SEM_ONLY))
-    ; /* nothing to do */
-  else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SIGNED))
-    (*info->fprintf_func) (info->stream, "%ld", value);
+  if (strcmp (option, "pseudoc") == 0)
+    asm_dialect = BPF_DIALECT_PSEUDOC;
+  else if (strcmp (option, "v1") == 0)
+    asm_bpf_version = BPF_V1;
+  else if (strcmp (option, "v2") == 0)
+    asm_bpf_version = BPF_V2;
+  else if (strcmp (option, "v3") == 0)
+    asm_bpf_version = BPF_V3;
+  else if (strcmp (option, "v4") == 0)
+    asm_bpf_version = BPF_V4;
+  else if (strcmp (option, "xbpf") == 0)
+    asm_bpf_version = BPF_XBPF;
+  else if (strcmp (option, "hex") == 0)
+    asm_obase = 16;
+  else if (strcmp (option, "oct") == 0)
+    asm_obase = 8;
+  else if (strcmp (option, "dec") == 0)
+    asm_obase = 10;
   else
-    (*info->fprintf_func) (info->stream, "0x%lx", value);
+    /* xgettext:c-format */
+    opcodes_error_handler (_("unrecognized disassembler option: %s"), option);
 }
 
-/* Default address handler.  */
-
 static void
-print_address (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
-	       void *dis_info,
-	       bfd_vma value,
-	       unsigned int attrs,
-	       bfd_vma pc ATTRIBUTE_UNUSED,
-	       int length ATTRIBUTE_UNUSED)
+parse_bpf_dis_options (const char *opts_in)
 {
-  disassemble_info *info = (disassemble_info *) dis_info;
-
-  /* Print the operand as directed by the attributes.  */
-  if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SEM_ONLY))
-    ; /* Nothing to do.  */
-  else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_PCREL_ADDR))
-    (*info->print_address_func) (value, info);
-  else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_ABS_ADDR))
-    (*info->print_address_func) (value, info);
-  else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SIGNED))
-    (*info->fprintf_func) (info->stream, "%ld", (long) value);
-  else
-    (*info->fprintf_func) (info->stream, "0x%lx", (long) value);
-}
+  char *opts = xstrdup (opts_in), *opt = opts, *opt_end = opts;
 
-/* Keyword print handler.  */
-
-static void
-print_keyword (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
-	       void *dis_info,
-	       CGEN_KEYWORD *keyword_table,
-	       long value,
-	       unsigned int attrs ATTRIBUTE_UNUSED)
-{
-  disassemble_info *info = (disassemble_info *) dis_info;
-  const CGEN_KEYWORD_ENTRY *ke;
+  for ( ; opt_end != NULL; opt = opt_end + 1)
+    {
+      if ((opt_end = strchr (opt, ',')) != NULL)
+	*opt_end = 0;
+      parse_bpf_dis_option (opt);
+    }
 
-  ke = cgen_keyword_lookup_value (keyword_table, value);
-  if (ke != NULL)
-    (*info->fprintf_func) (info->stream, "%s", ke->name);
-  else
-    (*info->fprintf_func) (info->stream, "???");
+  free (opts);
 }
-
-/* Default insn printer.
 
-   DIS_INFO is defined as `void *' so the disassembler needn't know anything
-   about disassemble_info.  */
+/* Auxiliary function used in print_insn_bpf below.  */
 
 static void
-print_insn_normal (CGEN_CPU_DESC cd,
-		   void *dis_info,
-		   const CGEN_INSN *insn,
-		   CGEN_FIELDS *fields,
-		   bfd_vma pc,
-		   int length)
+print_register (disassemble_info *info,
+                const char *tag, uint8_t regno)
 {
-  const CGEN_SYNTAX *syntax = CGEN_INSN_SYNTAX (insn);
-  disassemble_info *info = (disassemble_info *) dis_info;
-  const CGEN_SYNTAX_CHAR_TYPE *syn;
-
-  CGEN_INIT_PRINT (cd);
-
-  for (syn = CGEN_SYNTAX_STRING (syntax); *syn; ++syn)
-    {
-      if (CGEN_SYNTAX_MNEMONIC_P (*syn))
-	{
-	  (*info->fprintf_func) (info->stream, "%s", CGEN_INSN_MNEMONIC (insn));
-	  continue;
-	}
-      if (CGEN_SYNTAX_CHAR_P (*syn))
-	{
-	  (*info->fprintf_func) (info->stream, "%c", CGEN_SYNTAX_CHAR (*syn));
-	  continue;
-	}
-
-      /* We have an operand.  */
-      bpf_cgen_print_operand (cd, CGEN_SYNTAX_FIELD (*syn), info,
-				 fields, CGEN_INSN_ATTRS (insn), pc, length);
-    }
+  const char *fmt
+    = (asm_dialect == BPF_DIALECT_NORMAL
+       ? "%%r%d"
+       : ((*(tag + 2) == 'w')
+          ? "w%d"
+          : "r%d"));
+
+  (*info->fprintf_styled_func) (info->stream, dis_style_register, fmt, regno);
 }
-
-/* Subroutine of print_insn. Reads an insn into the given buffers and updates
-   the extract info.
-   Returns 0 if all is well, non-zero otherwise.  */
-
-static int
-read_insn (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
-	   bfd_vma pc,
-	   disassemble_info *info,
-	   bfd_byte *buf,
-	   int buflen,
-	   CGEN_EXTRACT_INFO *ex_info,
-	   unsigned long *insn_value)
-{
-  int status = (*info->read_memory_func) (pc, buf, buflen, info);
 
-  if (status != 0)
-    {
-      (*info->memory_error_func) (status, pc, info);
-      return -1;
-    }
-
-  ex_info->dis_info = info;
-  ex_info->valid = (1 << buflen) - 1;
-  ex_info->insn_bytes = buf;
-
-  *insn_value = bfd_get_bits (buf, buflen * 8, info->endian == BFD_ENDIAN_BIG);
-  return 0;
-}
+/* Main entry point.
+   Print one instruction from PC on INFO->STREAM.
+   Return the size of the instruction (in bytes).  */
 
-/* Utility to print an insn.
-   BUF is the base part of the insn, target byte order, BUFLEN bytes long.
-   The result is the size of the insn in bytes or zero for an unknown insn
-   or -1 if an error occurs fetching data (memory_error_func will have
-   been called).  */
-
-static int
-print_insn (CGEN_CPU_DESC cd,
-	    bfd_vma pc,
-	    disassemble_info *info,
-	    bfd_byte *buf,
-	    unsigned int buflen)
+int
+print_insn_bpf (bfd_vma pc, disassemble_info *info)
 {
-  CGEN_INSN_INT insn_value;
-  const CGEN_INSN_LIST *insn_list;
-  CGEN_EXTRACT_INFO ex_info;
-  int basesize;
-
-  /* Extract base part of instruction, just in case CGEN_DIS_* uses it. */
-  basesize = cd->base_insn_bitsize < buflen * 8 ?
-                                     cd->base_insn_bitsize : buflen * 8;
-  insn_value = cgen_get_insn_value (cd, buf, basesize, cd->insn_endian);
-
-
-  /* Fill in ex_info fields like read_insn would.  Don't actually call
-     read_insn, since the incoming buffer is already read (and possibly
-     modified a la m32r).  */
-  ex_info.valid = (1 << buflen) - 1;
-  ex_info.dis_info = info;
-  ex_info.insn_bytes = buf;
-
-  /* The instructions are stored in hash lists.
-     Pick the first one and keep trying until we find the right one.  */
-
-  insn_list = CGEN_DIS_LOOKUP_INSN (cd, (char *) buf, insn_value);
-  while (insn_list != NULL)
+  int insn_size = 8, status;
+  bfd_byte insn_bytes[16];
+  bpf_insn_word word = 0;
+  const struct bpf_opcode *insn = NULL;
+  enum bpf_endian endian = (info->endian == BFD_ENDIAN_LITTLE
+                            ? BPF_ENDIAN_LITTLE : BPF_ENDIAN_BIG);
+
+  /* Handle bpf-specific command-line options.  */
+  if (info->disassembler_options != NULL)
     {
-      const CGEN_INSN *insn = insn_list->insn;
-      CGEN_FIELDS fields;
-      int length;
-      unsigned long insn_value_cropped;
-
-#ifdef CGEN_VALIDATE_INSN_SUPPORTED
-      /* Not needed as insn shouldn't be in hash lists if not supported.  */
-      /* Supported by this cpu?  */
-      if (! bpf_cgen_insn_supported (cd, insn))
-        {
-          insn_list = CGEN_DIS_NEXT_INSN (insn_list);
-	  continue;
-        }
-#endif
-
-      /* Basic bit mask must be correct.  */
-      /* ??? May wish to allow target to defer this check until the extract
-	 handler.  */
-
-      /* Base size may exceed this instruction's size.  Extract the
-         relevant part from the buffer. */
-      if ((unsigned) (CGEN_INSN_BITSIZE (insn) / 8) < buflen &&
-	  (unsigned) (CGEN_INSN_BITSIZE (insn) / 8) <= sizeof (unsigned long))
-	insn_value_cropped = bfd_get_bits (buf, CGEN_INSN_BITSIZE (insn),
-					   info->endian == BFD_ENDIAN_BIG);
-      else
-	insn_value_cropped = insn_value;
-
-      if ((insn_value_cropped & CGEN_INSN_BASE_MASK (insn))
-	  == CGEN_INSN_BASE_VALUE (insn))
-	{
-	  /* Printing is handled in two passes.  The first pass parses the
-	     machine insn and extracts the fields.  The second pass prints
-	     them.  */
-
-	  /* Make sure the entire insn is loaded into insn_value, if it
-	     can fit.  */
-	  if (((unsigned) CGEN_INSN_BITSIZE (insn) > cd->base_insn_bitsize) &&
-	      (unsigned) (CGEN_INSN_BITSIZE (insn) / 8) <= sizeof (unsigned long))
-	    {
-	      unsigned long full_insn_value;
-	      int rc = read_insn (cd, pc, info, buf,
-				  CGEN_INSN_BITSIZE (insn) / 8,
-				  & ex_info, & full_insn_value);
-	      if (rc != 0)
-		return rc;
-	      length = CGEN_EXTRACT_FN (cd, insn)
-		(cd, insn, &ex_info, full_insn_value, &fields, pc);
-	    }
-	  else
-	    length = CGEN_EXTRACT_FN (cd, insn)
-	      (cd, insn, &ex_info, insn_value_cropped, &fields, pc);
-
-	  /* Length < 0 -> error.  */
-	  if (length < 0)
-	    return length;
-	  if (length > 0)
-	    {
-	      CGEN_PRINT_FN (cd, insn) (cd, info, insn, &fields, pc, length);
-	      /* Length is in bits, result is in bytes.  */
-	      return length / 8;
-	    }
-	}
-
-      insn_list = CGEN_DIS_NEXT_INSN (insn_list);
+      parse_bpf_dis_options (info->disassembler_options);
+      /* Avoid repeteadly parsing the options.  */
+      info->disassembler_options = NULL;
     }
 
-  return 0;
-}
-
-/* Default value for CGEN_PRINT_INSN.
-   The result is the size of the insn in bytes or zero for an unknown insn
-   or -1 if an error occured fetching bytes.  */
-
-#ifndef CGEN_PRINT_INSN
-#define CGEN_PRINT_INSN default_print_insn
-#endif
-
-static int
-default_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
-{
-  bfd_byte buf[CGEN_MAX_INSN_SIZE];
-  int buflen;
-  int status;
-
-  /* Attempt to read the base part of the insn.  */
-  buflen = cd->base_insn_bitsize / 8;
-  status = (*info->read_memory_func) (pc, buf, buflen, info);
-
-  /* Try again with the minimum part, if min < base.  */
-  if (status != 0 && (cd->min_insn_bitsize < cd->base_insn_bitsize))
-    {
-      buflen = cd->min_insn_bitsize / 8;
-      status = (*info->read_memory_func) (pc, buf, buflen, info);
-    }
+  /* Print eight bytes per line.  */
+  info->bytes_per_chunk = 1;
+  info->bytes_per_line = 8;
 
+  /* Read an instruction word.  */
+  status = (*info->read_memory_func) (pc, insn_bytes, 8, info);
   if (status != 0)
     {
       (*info->memory_error_func) (status, pc, info);
       return -1;
     }
+  word = (bpf_insn_word) bfd_getb64 (insn_bytes);
 
-  return print_insn (cd, pc, info, buf, buflen);
-}
+  /* Try to match an instruction with it.  */
+  insn = bpf_match_insn (word, endian, asm_bpf_version);
 
-/* Main entry point.
-   Print one instruction from PC on INFO->STREAM.
-   Return the size of the instruction (in bytes).  */
-
-typedef struct cpu_desc_list
-{
-  struct cpu_desc_list *next;
-  CGEN_BITSET *isa;
-  int mach;
-  int endian;
-  int insn_endian;
-  CGEN_CPU_DESC cd;
-} cpu_desc_list;
-
-int
-print_insn_bpf (bfd_vma pc, disassemble_info *info)
-{
-  static cpu_desc_list *cd_list = 0;
-  cpu_desc_list *cl = 0;
-  static CGEN_CPU_DESC cd = 0;
-  static CGEN_BITSET *prev_isa;
-  static int prev_mach;
-  static int prev_endian;
-  static int prev_insn_endian;
-  int length;
-  CGEN_BITSET *isa;
-  int mach;
-  int endian = (info->endian == BFD_ENDIAN_BIG
-		? CGEN_ENDIAN_BIG
-		: CGEN_ENDIAN_LITTLE);
-  int insn_endian = (info->endian_code == BFD_ENDIAN_BIG
-                     ? CGEN_ENDIAN_BIG
-                     : CGEN_ENDIAN_LITTLE);
-  enum bfd_architecture arch;
-
-  /* ??? gdb will set mach but leave the architecture as "unknown" */
-#ifndef CGEN_BFD_ARCH
-#define CGEN_BFD_ARCH bfd_arch_bpf
-#endif
-  arch = info->arch;
-  if (arch == bfd_arch_unknown)
-    arch = CGEN_BFD_ARCH;
-
-  /* There's no standard way to compute the machine or isa number
-     so we leave it to the target.  */
-#ifdef CGEN_COMPUTE_MACH
-  mach = CGEN_COMPUTE_MACH (info);
-#else
-  mach = info->mach;
-#endif
-
-#ifdef CGEN_COMPUTE_ISA
-  {
-    static CGEN_BITSET *permanent_isa;
-
-    if (!permanent_isa)
-      permanent_isa = cgen_bitset_create (MAX_ISAS);
-    isa = permanent_isa;
-    cgen_bitset_clear (isa);
-    cgen_bitset_add (isa, CGEN_COMPUTE_ISA (info));
-  }
-#else
-  isa = info->private_data;
-#endif
-
-  /* If we've switched cpu's, try to find a handle we've used before */
-  if (cd
-      && (cgen_bitset_compare (isa, prev_isa) != 0
-	  || mach != prev_mach
-	  || endian != prev_endian))
+  /* Print it out.  */
+  if (insn)
     {
-      cd = 0;
-      for (cl = cd_list; cl; cl = cl->next)
-	{
-	  if (cgen_bitset_compare (cl->isa, isa) == 0 &&
-	      cl->mach == mach &&
-	      cl->endian == endian)
-	    {
-	      cd = cl->cd;
- 	      prev_isa = cd->isas;
-	      break;
-	    }
-	}
-    }
+      const char *insn_tmpl
+        = asm_dialect == BPF_DIALECT_NORMAL ? insn->normal : insn->pseudoc;
+      const char *p = insn_tmpl;
 
-  /* If we haven't initialized yet, initialize the opcode table.  */
-  if (! cd)
-    {
-      const bfd_arch_info_type *arch_type = bfd_lookup_arch (arch, mach);
-      const char *mach_name;
-
-      if (!arch_type)
-	abort ();
-      mach_name = arch_type->printable_name;
-
-      prev_isa = cgen_bitset_copy (isa);
-      prev_mach = mach;
-      prev_endian = endian;
-      prev_insn_endian = insn_endian;
-      cd = bpf_cgen_cpu_open (CGEN_CPU_OPEN_ISAS, prev_isa,
-				 CGEN_CPU_OPEN_BFDMACH, mach_name,
-				 CGEN_CPU_OPEN_ENDIAN, prev_endian,
-                                 CGEN_CPU_OPEN_INSN_ENDIAN, prev_insn_endian,
-				 CGEN_CPU_OPEN_END);
-      if (!cd)
-	abort ();
-
-      /* Save this away for future reference.  */
-      cl = xmalloc (sizeof (struct cpu_desc_list));
-      cl->cd = cd;
-      cl->isa = prev_isa;
-      cl->mach = mach;
-      cl->endian = endian;
-      cl->next = cd_list;
-      cd_list = cl;
-
-      bpf_cgen_init_dis (cd);
+      /* Print the template contents completed with the instruction
+         operands.  */
+      for (p = insn_tmpl; *p != '\0';)
+        {
+          switch (*p)
+            {
+            case ' ':
+              /* Single space prints to nothing.  */
+              p += 1;
+              break;
+            case '%':
+              if (*(p + 1) == '%')
+                {
+                  (*info->fprintf_styled_func) (info->stream, dis_style_text, "%%");
+                  p += 2;
+                }
+              else if (*(p + 1) == 'w' || *(p + 1) == 'W')
+                {
+                  /* %W prints to a single space.  */
+                  (*info->fprintf_styled_func) (info->stream, dis_style_text, " ");
+                  p += 2;
+                }
+              else if (strncmp (p, "%dr", 3) == 0)
+                {
+                  print_register (info, p, bpf_extract_dst (word, endian));
+                  p += 3;
+                }
+              else if (strncmp (p, "%sr", 3) == 0)
+                {
+                  print_register (info, p, bpf_extract_src (word, endian));
+                  p += 3;
+                }
+              else if (strncmp (p, "%dw", 3) == 0)
+                {
+                  print_register (info, p, bpf_extract_dst (word, endian));
+                  p += 3;
+                }
+              else if (strncmp (p, "%sw", 3) == 0)
+                {
+                  print_register (info, p, bpf_extract_src (word, endian));
+                  p += 3;
+                }
+              else if (strncmp (p, "%i32", 4) == 0
+                       || strncmp (p, "%d32", 4) == 0
+                       || strncmp (p, "%I32", 4) == 0)
+                {
+                  int32_t imm32 = bpf_extract_imm32 (word, endian);
+
+                  if (p[1] == 'I')
+                    (*info->fprintf_styled_func) (info->stream, dis_style_immediate,
+                                                  "%s",
+                                                  asm_obase != 10 || imm32 > 0 ? "+" : "");
+                  (*info->fprintf_styled_func) (info->stream, dis_style_immediate,
+                                                asm_obase == 10 ? "%" PRIi32
+                                                : asm_obase == 8 ? "%" PRIo32
+                                                : "0x%" PRIx32,
+                                                imm32);
+                  p += 4;
+                }
+              else if (strncmp (p, "%o16", 4) == 0
+                       || strncmp (p, "%d16", 4) == 0)
+                {
+                  int16_t offset16 = bpf_extract_offset16 (word, endian);
+
+                  if (p[1] == 'o')
+                    (*info->fprintf_styled_func) (info->stream, dis_style_immediate,
+                                                  "%s",
+                                                  asm_obase != 10 || offset16 > 0 ? "+" : "");
+                  if (asm_obase == 16 || asm_obase == 8)
+                    (*info->fprintf_styled_func) (info->stream, dis_style_immediate,
+                                                  asm_obase == 8 ? "0%" PRIo16 : "0x%" PRIx16,
+                                                  (uint16_t) offset16);
+                  else
+                    (*info->fprintf_styled_func) (info->stream, dis_style_immediate,
+                                                  "%" PRIi16, offset16);
+                  p += 4;
+                }
+              else if (strncmp (p, "%i64", 4) == 0)
+                {
+                  bpf_insn_word word2 = 0;
+
+                  status = (*info->read_memory_func) (pc + 8, insn_bytes + 8,
+                                                          8, info);
+                  if (status != 0)
+                    {
+                      (*info->memory_error_func) (status, pc + 8, info);
+                      return -1;
+                    }
+                  word2 = (bpf_insn_word) bfd_getb64 (insn_bytes + 8);
+
+                  (*info->fprintf_styled_func) (info->stream, dis_style_immediate,
+                                                asm_obase == 10 ? "%" PRIi64
+                                                : asm_obase == 8 ? "0%" PRIo64
+                                                : "0x%" PRIx64,
+                                                bpf_extract_imm64 (word, word2, endian));
+                  insn_size = 16;
+                  p += 4;
+                }
+              else
+                {
+                  /* xgettext:c-format */
+                  opcodes_error_handler (_("# internal error, unknown tag in opcode template (%s)"),
+                                         insn_tmpl);
+                  return -1;
+                }
+              break;
+            default:
+              /* Any other character is printed literally.  */
+              (*info->fprintf_styled_func) (info->stream, dis_style_text, "%c", *p);
+              p += 1;
+            }
+        }
     }
+  else
+    (*info->fprintf_styled_func) (info->stream, dis_style_text, "<unknown>");
 
-  /* We try to have as much common code as possible.
-     But at this point some targets need to take over.  */
-  /* ??? Some targets may need a hook elsewhere.  Try to avoid this,
-     but if not possible try to move this hook elsewhere rather than
-     have two hooks.  */
-  length = CGEN_PRINT_INSN (cd, pc, info);
-  if (length > 0)
-    return length;
-  if (length < 0)
-    return -1;
-
-  (*info->fprintf_func) (info->stream, UNKNOWN_INSN_MSG);
-  return cd->default_insn_bitsize / 8;
+  return insn_size;
 }