GDB PR tdep/8282: MIPS: Wire in `set disassembler-options'

Implement MIPS target support for passing options to the disassembler,
complementing commit 65b48a81404c ("GDB: Add support for the new
set/show disassembler-options commands.").

This includes options that expect an argument, so adjust the generic
code and data structures used so as to handle such options.  So as to
give backends syntax flexibility no specific delimiter has been defined
to separate options from their respective arguments, so it has to be
included as the last character of the option name.  Completion code
however has not been adjusted and consequently option arguments cannot
be completed at this time.

Also the MIPS target has non-empty defaults for the options, so that ABI
names for the general-purpose registers respect our `set mips abi ...'
setting rather than always being determined from the ELF headers of the
binary file selected.  Handle these defaults as implicit options, never
shown to the user and always prepended to the user-specified options, so
that the latters can override the defaults.

The resulting output for the MIPS target is as follows:

(gdb) show disassembler-options
The current disassembler options are ''

The following disassembler options are supported for use with the
'set disassembler-options <option>[,<option>...]' command:

  no-aliases      Use canonical instruction forms.

  msa             Recognize MSA instructions.

  virt            Recognize the virtualization ASE instructions.

  xpa             Recognize the eXtended Physical Address (XPA) ASE
                  instructions.

  ginv            Recognize the Global INValidate (GINV) ASE instructions.

  gpr-names=ABI   Print GPR names according to specified ABI.
                  Default: based on binary being disassembled.

  fpr-names=ABI   Print FPR names according to specified ABI.
                  Default: numeric.

  cp0-names=ARCH  Print CP0 register names according to specified architecture.
                  Default: based on binary being disassembled.

  hwr-names=ARCH  Print HWR names according to specified architecture.
                  Default: based on binary being disassembled.

  reg-names=ABI   Print GPR and FPR names according to specified ABI.

  reg-names=ARCH  Print CP0 register and HWR names according to specified
                  architecture.

  For the options above, the following values are supported for "ABI":
    numeric 32 n32 64

  For the options above, the following values are supported for "ARCH":
    numeric r3000 r3900 r4000 r4010 vr4100 vr4111 vr4120 r4300 r4400 r4600
    r4650 r5000 vr5400 vr5500 r5900 r6000 rm7000 rm9000 r8000 r10000 r12000
    r14000 r16000 mips5 mips32 mips32r2 mips32r3 mips32r5 mips32r6 mips64
    mips64r2 mips64r3 mips64r5 mips64r6 interaptiv-mr2 sb1 loongson2e
    loongson2f loongson3a octeon octeon+ octeon2 octeon3 xlr xlp
(gdb)

which corresponds to what `objdump --help' used to print for the MIPS
target, with minor formatting changes, most notably option argument
lists being wrapped, but also the amount of white space separating
options from the respective descriptions.  The relevant part the new
code is now also used by `objdump --help', which means these formatting
changes apply to both outputs, except for argument list wrapping, which
is GDB-specific.

This also adds a separating new line between the heading and option
lists where descriptions are provided, hence:

(gdb) set architecture s390:31-bit
(gdb) show disassembler-options
The current disassembler options are ''

The following disassembler options are supported for use with the
'set disassembler-options <option>[,<option>...]' command:

  esa         Disassemble in ESA architecture mode
  zarch       Disassemble in z/Architecture mode
  insnlength  Print unknown instructions according to length from first two bits
(gdb)

but:

(gdb) set architecture powerpc:common
(gdb) show disassembler-options
The current disassembler options are ''

The following disassembler options are supported for use with the
'set disassembler-options <option>[,<option>...]' command:
  403, 405, 440, 464, 476, 601, 603, 604, 620, 7400, 7410, 7450, 7455, 750cl,
  821, 850, 860, a2, altivec, any, booke, booke32, cell, com, e200z4, e300,
  e500, e500mc, e500mc64, e5500, e6500, e500x2, efs, efs2, power4, power5,
  power6, power7, power8, power9, ppc, ppc32, 32, ppc64, 64, ppc64bridge,
  ppcps, pwr, pwr2, pwr4, pwr5, pwr5x, pwr6, pwr7, pwr8, pwr9, pwrx, raw, spe,
  spe2, titan, vle, vsx
(gdb)

Existing affected target backends have been adjusted accordingly.

This has been verified manually with:

(gdb) set architecture arm
(gdb) set architecture powerpc:common
(gdb) set architecture s390:31-bit

to cause no issues with the `show disassembler-options' and `set
disassembler-options' commands.  A test case for the MIPS target has
also been provided, covering the default settings with ABI overrides as
well as disassembler option overrides.

2018-07-02  Maciej W. Rozycki  <macro@mips.com>
            Simon Marchi  <simon.marchi@polymtl.ca>

	include/
	PR tdep/8282
	* dis-asm.h (disasm_option_arg_t): New typedef.
	(disasm_options_and_args_t): Likewise.
	(disasm_options_t): Add `arg' member, document members.
	(disassembler_options_mips): New prototype.
	(disassembler_options_arm, disassembler_options_powerpc)
	(disassembler_options_s390): Update prototypes.

	opcodes/
	PR tdep/8282
	* mips-dis.c (mips_option_arg_t): New enumeration.
	(mips_options): New variable.
	(disassembler_options_mips): New function.
	(print_mips_disassembler_options): Reimplement in terms of
	`disassembler_options_mips'.
	* arm-dis.c (disassembler_options_arm): Adapt to using the
	`disasm_options_and_args_t' structure.
	* ppc-dis.c (disassembler_options_powerpc): Likewise.
	* s390-dis.c (disassembler_options_s390): Likewise.

	gdb/
	PR tdep/8282
	* disasm.h (gdb_disassembler): Add
	`m_disassembler_options_holder'. member
	* disasm.c (get_all_disassembler_options): New function.
	(gdb_disassembler::gdb_disassembler): Use it.
	(gdb_buffered_insn_length_init_dis): Likewise.
	(gdb_buffered_insn_length): Adjust accordingly.
	(set_disassembler_options): Handle options with arguments.
	(show_disassembler_options_sfunc): Likewise.  Add a leading new
	line if showing options with descriptions.
	(disassembler_options_completer): Adapt to using the
	`disasm_options_and_args_t' structure.
	* mips-tdep.c (mips_disassembler_options): New variable.
	(mips_disassembler_options_o32): Likewise.
	(mips_disassembler_options_n32): Likewise.
	(mips_disassembler_options_n64): Likewise.
	(gdb_print_insn_mips): Don't set `disassembler_options'.
	(gdb_print_insn_mips_n32, gdb_print_insn_mips_n64): Remove
	functions.
	(mips_gdbarch_init): Always set `gdbarch_print_insn' to
	`gdb_print_insn_mips'.  Set `gdbarch_disassembler_options',
	`gdbarch_disassembler_options_implicit' and
	`gdbarch_valid_disassembler_options'.
	* arm-tdep.c (_initialize_arm_tdep): Adapt to using the
	`disasm_options_and_args_t' structure.
	* gdbarch.sh (disassembler_options_implicit): New `gdbarch'
	method.
	(valid_disassembler_options): Switch from `disasm_options_t' to
	the `disasm_options_and_args_t' structure.
	* NEWS: Document `set disassembler-options' support for the MIPS
	target.
	* gdbarch.h: Regenerate.
	* gdbarch.c: Regenerate.

	gdb/doc/
	PR tdep/8282
	* gdb.texinfo (Source and Machine Code): Document `set
	disassembler-options' support for the MIPS target.

	gdb/testsuite/
	PR tdep/8282
	* gdb.arch/mips-disassembler-options.exp: New test.
	* gdb.arch/mips-disassembler-options.s: New test source.

2 files changed, 54 insertions, 6 deletions

diff --git a/include/ChangeLog b/include/ChangeLog
index 8f11f79..de80801 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,13 @@
+2018-07-02  Maciej W. Rozycki  <macro@mips.com>
+
+	PR tdep/8282
+	* dis-asm.h (disasm_option_arg_t): New typedef.
+	(disasm_options_and_args_t): Likewise.
+	(disasm_options_t): Add `arg' member, document members.
+	(disassembler_options_mips): New prototype.
+	(disassembler_options_arm, disassembler_options_powerpc)
+	(disassembler_options_s390): Update prototypes.
+
 2018-06-29  Tamar Christina  <tamar.christina@arm.com>
 
 	PR binutils/23192
diff --git a/include/dis-asm.h b/include/dis-asm.h
index cb72b7d..77b9e61 100644
--- a/include/dis-asm.h
+++ b/include/dis-asm.h
@@ -222,16 +222,53 @@ typedef struct disassemble_info
 
 } disassemble_info;
 
-/* This struct is used to pass information about valid disassembler options
-   and their descriptions from the target to the generic GDB functions that
-   set and display them.  */
+/* This struct is used to pass information about valid disassembler
+   option arguments from the target to the generic GDB functions
+   that set and display them.  */
 
 typedef struct
 {
+  /* Option argument name to use in descriptions.  */
+  const char *name;
+
+  /* Vector of acceptable option argument values, NULL-terminated.  */
+  const char **values;
+} disasm_option_arg_t;
+
+/* This struct is used to pass information about valid disassembler
+   options, their descriptions and arguments from the target to the
+   generic GDB functions that set and display them.  Options are
+   defined by tuples of vector entries at each index.  */
+
+typedef struct
+{
+  /* Vector of option names, NULL-terminated.  */
   const char **name;
+
+  /* Vector of option descriptions or NULL if none to be shown.  */
   const char **description;
+
+  /* Vector of option argument information pointers or NULL if no
+     option accepts an argument.  NULL entries denote individual
+     options that accept no argument.  */
+  const disasm_option_arg_t **arg;
 } disasm_options_t;
 
+/* This struct is used to pass information about valid disassembler
+   options and arguments from the target to the generic GDB functions
+   that set and display them.  */
+
+typedef struct
+{
+  /* Valid disassembler options.  Individual options that support
+     an argument will refer to entries in the ARGS vector.  */
+  disasm_options_t options;
+
+  /* Vector of acceptable option arguments, NULL-terminated.  This
+     collects all possible option argument choices, some of which
+     may be shared by different options from the OPTIONS member.  */
+  disasm_option_arg_t *args;
+} disasm_options_and_args_t;
 
 /* Standard disassemblers.  Disassemble one instruction at the given
    target address.  Return number of octets processed.  */
@@ -266,9 +303,10 @@ extern bfd_boolean arm_symbol_is_valid (asymbol *, struct disassemble_info *);
 extern void disassemble_init_powerpc (struct disassemble_info *);
 extern void disassemble_init_s390 (struct disassemble_info *);
 extern void disassemble_init_wasm32 (struct disassemble_info *);
-extern const disasm_options_t *disassembler_options_powerpc (void);
-extern const disasm_options_t *disassembler_options_arm (void);
-extern const disasm_options_t *disassembler_options_s390 (void);
+extern const disasm_options_and_args_t *disassembler_options_arm (void);
+extern const disasm_options_and_args_t *disassembler_options_mips (void);
+extern const disasm_options_and_args_t *disassembler_options_powerpc (void);
+extern const disasm_options_and_args_t *disassembler_options_s390 (void);
 
 /* Fetch the disassembler for a given architecture ARC, endianess (big
    endian if BIG is true), bfd_mach value MACH, and ABFD, if that support