RX: Convert target-description

Message ID 20190821033301.45309-1-ysato@users.sourceforge.jp
State New, archived
Headers

Commit Message

Yoshinori Sato Aug. 21, 2019, 3:33 a.m. UTC
  gdb/ChangeLog

2019-08-21  Yoshinori Sato <ysato@users.sourceforge.jp>

	* gdb/rx-tdep.c (rx_register_names): New.
	(rx_register_name): Use rx_register_names.
	(rx_register_name): Add check range.
	(rx_register_g_packet_guesses): New.
	(rx_gdbarch_init): Convert target-descriptions.
	(_initialize_rx_tdep): Add initialize_tdesc_rx.
	* gdb/features/Makefile: Add rx.xml.
	* gdb/features/rx.xml: New.
---
 gdb/features/Makefile |  2 ++
 gdb/features/rx.xml   | 70 ++++++++++++++++++++++++++++++++++++
 gdb/rx-tdep.c         | 99 ++++++++++++++++++++++++++++++---------------------
 3 files changed, 130 insertions(+), 41 deletions(-)
 create mode 100644 gdb/features/rx.xml
  

Comments

Andrew Burgess Aug. 21, 2019, 9:24 a.m. UTC | #1
Thanks for the patch.

* Yoshinori Sato <ysato@users.sourceforge.jp> [2019-08-21 12:33:01 +0900]:

GDB patches usually include a brief description to the patch before
the changelog entry in the commit message, even if its just one
sentence like:

  Convert the RX target to make use of target descriptions.

> gdb/ChangeLog
> 
> 2019-08-21  Yoshinori Sato <ysato@users.sourceforge.jp>
> 
> 	* gdb/rx-tdep.c (rx_register_names): New.
> 	(rx_register_name): Use rx_register_names.
> 	(rx_register_name): Add check range.
> 	(rx_register_g_packet_guesses): New.
> 	(rx_gdbarch_init): Convert target-descriptions.
> 	(_initialize_rx_tdep): Add initialize_tdesc_rx.
> 	* gdb/features/Makefile: Add rx.xml.
> 	* gdb/features/rx.xml: New.

You should generate and commit the gdb/features/rx.c file as well.
These files are not automatically generated by the build system and we
rely on people regenerating them when the xml file changes.

There's a few minor coding standard issues I've pointed out below.

> ---
>  gdb/features/Makefile |  2 ++
>  gdb/features/rx.xml   | 70 ++++++++++++++++++++++++++++++++++++
>  gdb/rx-tdep.c         | 99 ++++++++++++++++++++++++++++++---------------------
>  3 files changed, 130 insertions(+), 41 deletions(-)
>  create mode 100644 gdb/features/rx.xml
> 
> diff --git a/gdb/features/Makefile b/gdb/features/Makefile
> index 0c84faf405..2b65d46df0 100644
> --- a/gdb/features/Makefile
> +++ b/gdb/features/Makefile
> @@ -161,6 +161,7 @@ XMLTOC = \
>  	rs6000/powerpc-vsx64.xml \
>  	rs6000/powerpc-vsx64l.xml \
>  	rs6000/rs6000.xml \
> +	rx.xml \
>  	s390-linux32.xml \
>  	s390-linux32v1.xml \
>  	s390-linux32v2.xml \
> @@ -238,6 +239,7 @@ FEATURE_XMLFILES = aarch64-core.xml \
>  	riscv/64bit-cpu.xml \
>  	riscv/64bit-csr.xml \
>  	riscv/64bit-fpu.xml \
> +	rx.xml \
>  	tic6x-c6xp.xml \
>  	tic6x-core.xml \
>  	tic6x-gp.xml
> diff --git a/gdb/features/rx.xml b/gdb/features/rx.xml
> new file mode 100644
> index 0000000000..b5aa9ac4a8
> --- /dev/null
> +++ b/gdb/features/rx.xml
> @@ -0,0 +1,70 @@
> +<?xml version="1.0"?>
> +<!-- Copyright (C) 2019 Free Software Foundation, Inc.
> +
> +     Copying and distribution of this file, with or without modification,
> +     are permitted in any medium without royalty provided the copyright
> +     notice and this notice are preserved.  -->
> +
> +<!DOCTYPE feature SYSTEM "gdb-target.dtd">
> +<feature name="org.gnu.gdb.rx.core">
> +  <reg name="r0" bitsize="32" type="data_ptr"/>
> +  <reg name="r1" bitsize="32" type="uint32"/>
> +  <reg name="r2" bitsize="32" type="uint32"/>
> +  <reg name="r3" bitsize="32" type="uint32"/>
> +  <reg name="r4" bitsize="32" type="uint32"/>
> +  <reg name="r5" bitsize="32" type="uint32"/>
> +  <reg name="r6" bitsize="32" type="uint32"/>
> +  <reg name="r7" bitsize="32" type="uint32"/>
> +  <reg name="r8" bitsize="32" type="uint32"/>
> +  <reg name="r9" bitsize="32" type="uint32"/>
> +  <reg name="r10" bitsize="32" type="uint32"/>
> +  <reg name="r11" bitsize="32" type="uint32"/>
> +  <reg name="r12" bitsize="32" type="uint32"/>
> +  <reg name="r13" bitsize="32" type="uint32"/>
> +  <reg name="r14" bitsize="32" type="uint32"/>
> +  <reg name="r15" bitsize="32" type="uint32"/>
> +
> +  <flags id="psw_flags" size="4">
> +    <field name="C" start="0" end="0"/>
> +    <field name="Z" start="1" end="1"/>
> +    <field name="S" start="2" end="2"/>
> +    <field name="O" start="3" end="3"/>
> +    <field name="I" start="16" end="16"/>
> +    <field name="U" start="17" end="17"/>
> +    <field name="PM" start="20" end="20"/>
> +    <field name="IPL" start="24" end="27"/>
> +  </flags>
> +
> +  <flags id="fpsw_flags" size="4">
> +    <field name="RM" start="0" end="1"/>
> +    <field name="CV" start="2" end="2"/>
> +    <field name="CO" start="3" end="3"/>
> +    <field name="CZ" start="4" end="4"/>
> +    <field name="CU" start="5" end="5"/>
> +    <field name="CX" start="6" end="6"/>
> +    <field name="CE" start="7" end="7"/>
> +    <field name="DN" start="8" end="8"/>
> +    <field name="EV" start="10" end="10"/>
> +    <field name="EO" start="11" end="11"/>
> +    <field name="EZ" start="12" end="12"/>
> +    <field name="EU" start="13" end="13"/>
> +    <field name="EX" start="14" end="14"/>
> +    <field name="FV" start="26" end="26"/>
> +    <field name="FO" start="27" end="27"/>
> +    <field name="FZ" start="28" end="28"/>
> +    <field name="FU" start="29" end="29"/>
> +    <field name="FX" start="30" end="30"/>
> +    <field name="FS" start="31" end="31"/>
> +  </flags>
> +
> +  <reg name="usp" bitsize="32" type="data_ptr"/>
> +  <reg name="isp" bitsize="32" type="data_ptr"/>
> +  <reg name="psw" bitsize="32" type="psw_flags"/>
> +  <reg name="pc" bitsize="32" type="code_ptr"/>
> +  <reg name="intb" bitsize="32" type="data_ptr"/>
> +  <reg name="bpsw" bitsize="32" type="psw_flags"/>
> +  <reg name="bpc" bitsize="32" type="code_ptr"/>
> +  <reg name="fintv" bitsize="32" type="code_ptr"/>
> +  <reg name="fpsw" bitsize="32" type="fpsw_flags"/>
> +  <reg name="acc" bitsize="64" type="uint64"/>
> +</feature>
> diff --git a/gdb/rx-tdep.c b/gdb/rx-tdep.c
> index 4cbf919db9..b3398f122a 100644
> --- a/gdb/rx-tdep.c
> +++ b/gdb/rx-tdep.c
> @@ -33,11 +33,15 @@
>  #include "value.h"
>  #include "gdbcore.h"
>  #include "dwarf2-frame.h"
> +#include "remote.h"
> +#include "target-descriptions.h"
>  
>  #include "elf/rx.h"
>  #include "elf-bfd.h"
>  #include <algorithm>
>  
> +#include "features/rx.c"
> +
>  /* Certain important register numbers.  */
>  enum
>  {
> @@ -114,40 +118,21 @@ struct rx_prologue
>    int reg_offset[RX_NUM_REGS];
>  };
>  
> +static const char *const rx_register_names[] = {
> +  "r0",  "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
> +  "r8",  "r9",  "r10", "r11", "r12", "r13", "r14", "r15",
> +  "usp", "isp", "psw", "pc",  "intb", "bpsw","bpc","fintv",
> +  "fpsw", "acc",
> +};

All file level variables and functions should have a header comment.

> +
>  /* Implement the "register_name" gdbarch method.  */
>  static const char *
>  rx_register_name (struct gdbarch *gdbarch, int regnr)
>  {
> -  static const char *const reg_names[] = {
> -    "r0",
> -    "r1",
> -    "r2",
> -    "r3",
> -    "r4",
> -    "r5",
> -    "r6",
> -    "r7",
> -    "r8",
> -    "r9",
> -    "r10",
> -    "r11",
> -    "r12",
> -    "r13",
> -    "r14",
> -    "r15",
> -    "usp",
> -    "isp",
> -    "psw",
> -    "pc",
> -    "intb",
> -    "bpsw",
> -    "bpc",
> -    "fintv",
> -    "fpsw",
> -    "acc"
> -  };
> -
> -  return reg_names[regnr];
> +  if (regnr >= 0 && regnr < RX_NUM_REGS)
> +    return rx_register_names[regnr];
> +  else
> +    return NULL;
>  }
>  
>  /* Construct the flags type for PSW and BPSW.  */
> @@ -1037,6 +1022,14 @@ rx_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
>      return -1;
>  }
>  
> +static void
> +rx_register_g_packet_guesses (struct gdbarch *gdbarch)
> +{
> +  register_remote_g_packet_guess (gdbarch,
> +                                  4 * RX_NUM_REGS,
> +                                  tdesc_rx);
> +}

Header comment again.

> +
>  /* Allocate and initialize a gdbarch object.  */
>  static struct gdbarch *
>  rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> @@ -1044,6 +1037,8 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>    struct gdbarch *gdbarch;
>    struct gdbarch_tdep *tdep;
>    int elf_flags;
> +  struct tdesc_arch_data *tdesc_data = NULL;
> +  const struct target_desc *tdesc = info.target_desc;
>  
>    /* Extract the elf_flags if available.  */
>    if (info.abfd != NULL
> @@ -1065,8 +1060,33 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>        return arches->gdbarch;
>      }
>  
> -  /* None found, create a new architecture from the information
> -     provided.  */
> +  if (tdesc == NULL)
> +      tdesc = tdesc_rx;
> +
> +  /* Check any target description for validity.  */
> +  if (tdesc_has_registers (tdesc))
> +    {
> +      const struct tdesc_feature *feature;
> +      int valid_p = 0;

This should be a bool.

> +      int i = 0;

This can move down into the if block scope.

> +      feature = tdesc_find_feature (tdesc, "org.gnu.gdb.rx.core");
> +
> +      if (feature != NULL)
> +	{
> +	  tdesc_data = tdesc_data_alloc ();
> +	  valid_p = 1;
> +	  for (i = 0; i < RX_NUM_REGS; i++)
> +	    valid_p &= tdesc_numbered_register (feature, tdesc_data, i,
> +                                            rx_register_names[i]);
> +	}
> +
> +      if (!valid_p)
> +	{
> +	  tdesc_data_cleanup (tdesc_data);
> +	  return NULL;
> +	}
> +    }
> +
>    tdep = XCNEW (struct gdbarch_tdep);
>    gdbarch = gdbarch_alloc (&info, tdep);
>    tdep->elf_flags = elf_flags;
> @@ -1083,15 +1103,6 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>    set_gdbarch_sw_breakpoint_from_kind (gdbarch, rx_breakpoint::bp_from_kind);
>    set_gdbarch_skip_prologue (gdbarch, rx_skip_prologue);
>  
> -  /* Target builtin data types.  */
> -  set_gdbarch_char_signed (gdbarch, 0);
> -  set_gdbarch_short_bit (gdbarch, 16);
> -  set_gdbarch_int_bit (gdbarch, 32);
> -  set_gdbarch_long_bit (gdbarch, 32);
> -  set_gdbarch_long_long_bit (gdbarch, 64);
> -  set_gdbarch_ptr_bit (gdbarch, 32);
> -  set_gdbarch_float_bit (gdbarch, 32);
> -  set_gdbarch_float_format (gdbarch, floatformats_ieee_single);

I don't understand why these are being deleted.  This doesn't feel
like it should be related to conversion to target descriptions.

>    if (elf_flags & E_FLAG_RX_64BIT_DOUBLES)
>      {
>        set_gdbarch_double_bit (gdbarch, 64);
> @@ -1115,6 +1126,8 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>    dwarf2_append_unwinders (gdbarch);
>    frame_unwind_append_unwinder (gdbarch, &rx_frame_unwind);
>  
> +  rx_register_g_packet_guesses (gdbarch);
> +
>    /* Methods setting up a dummy call, and extracting the return value from
>       a call.  */
>    set_gdbarch_push_dummy_call (gdbarch, rx_push_dummy_call);
> @@ -1123,6 +1136,9 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>    /* Virtual tables.  */
>    set_gdbarch_vbit_in_delta (gdbarch, 1);
>  
> +  if (tdesc_data != NULL)
> +    tdesc_use_registers (gdbarch, tdesc, tdesc_data);

I'm confused by the 'tdesc_data != NULL' check here, my reading of
things is that either:

  1. Target doesn't provide a target description, we fall back to the
  built in tdesc_rx, this will be valid, tdesc_data will not be NULL.

  2. The target provides a description, but its invalid, we bail out
  earlier after the validity check, we never reach this code.

  3. The target provides a description which is valid, tdesc_data will
  not be NULL.

I'd prefer to see a 'gdb_assert (tdesc_data != NULL)' immediately
after the earlier 'if (!valid_p)' block, and then after that just
assume tdesc_data is not NULL.

Actually, while we're moving code around, is there any reason that
this call to tdesc_use_registers couldn't move up to be just after the
valid_p check?  Given its closely related code?

> +
>    return gdbarch;
>  }
>  
> @@ -1132,4 +1148,5 @@ void
>  _initialize_rx_tdep (void)
>  {
>    register_gdbarch_init (bfd_arch_rx, rx_gdbarch_init);
> +  initialize_tdesc_rx ();
>  }
> -- 
> 2.11.0
> 

Thanks,
Andrew
  
Yoshinori Sato Aug. 21, 2019, 1:30 p.m. UTC | #2
On Wed, 21 Aug 2019 18:24:33 +0900,
Andrew Burgess wrote:
> 
> Thanks for the patch.
> 
> * Yoshinori Sato <ysato@users.sourceforge.jp> [2019-08-21 12:33:01 +0900]:
> 
> GDB patches usually include a brief description to the patch before
> the changelog entry in the commit message, even if its just one
> sentence like:
> 
>   Convert the RX target to make use of target descriptions.

OK.

> > gdb/ChangeLog
> > 
> > 2019-08-21  Yoshinori Sato <ysato@users.sourceforge.jp>
> > 
> > 	* gdb/rx-tdep.c (rx_register_names): New.
> > 	(rx_register_name): Use rx_register_names.
> > 	(rx_register_name): Add check range.
> > 	(rx_register_g_packet_guesses): New.
> > 	(rx_gdbarch_init): Convert target-descriptions.
> > 	(_initialize_rx_tdep): Add initialize_tdesc_rx.
> > 	* gdb/features/Makefile: Add rx.xml.
> > 	* gdb/features/rx.xml: New.
> 
> You should generate and commit the gdb/features/rx.c file as well.
> These files are not automatically generated by the build system and we
> rely on people regenerating them when the xml file changes.

OK.
I forgat add it file.
Added it.

> There's a few minor coding standard issues I've pointed out below.
> 
> > ---
> >  gdb/features/Makefile |  2 ++
> >  gdb/features/rx.xml   | 70 ++++++++++++++++++++++++++++++++++++
> >  gdb/rx-tdep.c         | 99 ++++++++++++++++++++++++++++++---------------------
> >  3 files changed, 130 insertions(+), 41 deletions(-)
> >  create mode 100644 gdb/features/rx.xml
> > 
> > diff --git a/gdb/features/Makefile b/gdb/features/Makefile
> > index 0c84faf405..2b65d46df0 100644
> > --- a/gdb/features/Makefile
> > +++ b/gdb/features/Makefile
> > @@ -161,6 +161,7 @@ XMLTOC = \
> >  	rs6000/powerpc-vsx64.xml \
> >  	rs6000/powerpc-vsx64l.xml \
> >  	rs6000/rs6000.xml \
> > +	rx.xml \
> >  	s390-linux32.xml \
> >  	s390-linux32v1.xml \
> >  	s390-linux32v2.xml \
> > @@ -238,6 +239,7 @@ FEATURE_XMLFILES = aarch64-core.xml \
> >  	riscv/64bit-cpu.xml \
> >  	riscv/64bit-csr.xml \
> >  	riscv/64bit-fpu.xml \
> > +	rx.xml \
> >  	tic6x-c6xp.xml \
> >  	tic6x-core.xml \
> >  	tic6x-gp.xml
> > diff --git a/gdb/features/rx.xml b/gdb/features/rx.xml
> > new file mode 100644
> > index 0000000000..b5aa9ac4a8
> > --- /dev/null
> > +++ b/gdb/features/rx.xml
> > @@ -0,0 +1,70 @@
> > +<?xml version="1.0"?>
> > +<!-- Copyright (C) 2019 Free Software Foundation, Inc.
> > +
> > +     Copying and distribution of this file, with or without modification,
> > +     are permitted in any medium without royalty provided the copyright
> > +     notice and this notice are preserved.  -->
> > +
> > +<!DOCTYPE feature SYSTEM "gdb-target.dtd">
> > +<feature name="org.gnu.gdb.rx.core">
> > +  <reg name="r0" bitsize="32" type="data_ptr"/>
> > +  <reg name="r1" bitsize="32" type="uint32"/>
> > +  <reg name="r2" bitsize="32" type="uint32"/>
> > +  <reg name="r3" bitsize="32" type="uint32"/>
> > +  <reg name="r4" bitsize="32" type="uint32"/>
> > +  <reg name="r5" bitsize="32" type="uint32"/>
> > +  <reg name="r6" bitsize="32" type="uint32"/>
> > +  <reg name="r7" bitsize="32" type="uint32"/>
> > +  <reg name="r8" bitsize="32" type="uint32"/>
> > +  <reg name="r9" bitsize="32" type="uint32"/>
> > +  <reg name="r10" bitsize="32" type="uint32"/>
> > +  <reg name="r11" bitsize="32" type="uint32"/>
> > +  <reg name="r12" bitsize="32" type="uint32"/>
> > +  <reg name="r13" bitsize="32" type="uint32"/>
> > +  <reg name="r14" bitsize="32" type="uint32"/>
> > +  <reg name="r15" bitsize="32" type="uint32"/>
> > +
> > +  <flags id="psw_flags" size="4">
> > +    <field name="C" start="0" end="0"/>
> > +    <field name="Z" start="1" end="1"/>
> > +    <field name="S" start="2" end="2"/>
> > +    <field name="O" start="3" end="3"/>
> > +    <field name="I" start="16" end="16"/>
> > +    <field name="U" start="17" end="17"/>
> > +    <field name="PM" start="20" end="20"/>
> > +    <field name="IPL" start="24" end="27"/>
> > +  </flags>
> > +
> > +  <flags id="fpsw_flags" size="4">
> > +    <field name="RM" start="0" end="1"/>
> > +    <field name="CV" start="2" end="2"/>
> > +    <field name="CO" start="3" end="3"/>
> > +    <field name="CZ" start="4" end="4"/>
> > +    <field name="CU" start="5" end="5"/>
> > +    <field name="CX" start="6" end="6"/>
> > +    <field name="CE" start="7" end="7"/>
> > +    <field name="DN" start="8" end="8"/>
> > +    <field name="EV" start="10" end="10"/>
> > +    <field name="EO" start="11" end="11"/>
> > +    <field name="EZ" start="12" end="12"/>
> > +    <field name="EU" start="13" end="13"/>
> > +    <field name="EX" start="14" end="14"/>
> > +    <field name="FV" start="26" end="26"/>
> > +    <field name="FO" start="27" end="27"/>
> > +    <field name="FZ" start="28" end="28"/>
> > +    <field name="FU" start="29" end="29"/>
> > +    <field name="FX" start="30" end="30"/>
> > +    <field name="FS" start="31" end="31"/>
> > +  </flags>
> > +
> > +  <reg name="usp" bitsize="32" type="data_ptr"/>
> > +  <reg name="isp" bitsize="32" type="data_ptr"/>
> > +  <reg name="psw" bitsize="32" type="psw_flags"/>
> > +  <reg name="pc" bitsize="32" type="code_ptr"/>
> > +  <reg name="intb" bitsize="32" type="data_ptr"/>
> > +  <reg name="bpsw" bitsize="32" type="psw_flags"/>
> > +  <reg name="bpc" bitsize="32" type="code_ptr"/>
> > +  <reg name="fintv" bitsize="32" type="code_ptr"/>
> > +  <reg name="fpsw" bitsize="32" type="fpsw_flags"/>
> > +  <reg name="acc" bitsize="64" type="uint64"/>
> > +</feature>
> > diff --git a/gdb/rx-tdep.c b/gdb/rx-tdep.c
> > index 4cbf919db9..b3398f122a 100644
> > --- a/gdb/rx-tdep.c
> > +++ b/gdb/rx-tdep.c
> > @@ -33,11 +33,15 @@
> >  #include "value.h"
> >  #include "gdbcore.h"
> >  #include "dwarf2-frame.h"
> > +#include "remote.h"
> > +#include "target-descriptions.h"
> >  
> >  #include "elf/rx.h"
> >  #include "elf-bfd.h"
> >  #include <algorithm>
> >  
> > +#include "features/rx.c"
> > +
> >  /* Certain important register numbers.  */
> >  enum
> >  {
> > @@ -114,40 +118,21 @@ struct rx_prologue
> >    int reg_offset[RX_NUM_REGS];
> >  };
> >  
> > +static const char *const rx_register_names[] = {
> > +  "r0",  "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
> > +  "r8",  "r9",  "r10", "r11", "r12", "r13", "r14", "r15",
> > +  "usp", "isp", "psw", "pc",  "intb", "bpsw","bpc","fintv",
> > +  "fpsw", "acc",
> > +};
> 
> All file level variables and functions should have a header comment.

OK.
Add comment.

> > +
> >  /* Implement the "register_name" gdbarch method.  */
> >  static const char *
> >  rx_register_name (struct gdbarch *gdbarch, int regnr)
> >  {
> > -  static const char *const reg_names[] = {
> > -    "r0",
> > -    "r1",
> > -    "r2",
> > -    "r3",
> > -    "r4",
> > -    "r5",
> > -    "r6",
> > -    "r7",
> > -    "r8",
> > -    "r9",
> > -    "r10",
> > -    "r11",
> > -    "r12",
> > -    "r13",
> > -    "r14",
> > -    "r15",
> > -    "usp",
> > -    "isp",
> > -    "psw",
> > -    "pc",
> > -    "intb",
> > -    "bpsw",
> > -    "bpc",
> > -    "fintv",
> > -    "fpsw",
> > -    "acc"
> > -  };
> > -
> > -  return reg_names[regnr];
> > +  if (regnr >= 0 && regnr < RX_NUM_REGS)
> > +    return rx_register_names[regnr];
> > +  else
> > +    return NULL;
> >  }
> >  
> >  /* Construct the flags type for PSW and BPSW.  */
> > @@ -1037,6 +1022,14 @@ rx_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
> >      return -1;
> >  }
> >  
> > +static void
> > +rx_register_g_packet_guesses (struct gdbarch *gdbarch)
> > +{
> > +  register_remote_g_packet_guess (gdbarch,
> > +                                  4 * RX_NUM_REGS,
> > +                                  tdesc_rx);
> > +}
> 
> Header comment again.
> 
> > +
> >  /* Allocate and initialize a gdbarch object.  */
> >  static struct gdbarch *
> >  rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> > @@ -1044,6 +1037,8 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> >    struct gdbarch *gdbarch;
> >    struct gdbarch_tdep *tdep;
> >    int elf_flags;
> > +  struct tdesc_arch_data *tdesc_data = NULL;
> > +  const struct target_desc *tdesc = info.target_desc;
> >  
> >    /* Extract the elf_flags if available.  */
> >    if (info.abfd != NULL
> > @@ -1065,8 +1060,33 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> >        return arches->gdbarch;
> >      }
> >  
> > -  /* None found, create a new architecture from the information
> > -     provided.  */
> > +  if (tdesc == NULL)
> > +      tdesc = tdesc_rx;
> > +
> > +  /* Check any target description for validity.  */
> > +  if (tdesc_has_registers (tdesc))
> > +    {
> > +      const struct tdesc_feature *feature;
> > +      int valid_p = 0;
> 
> This should be a bool.

OK.

> > +      int i = 0;
> 
> This can move down into the if block scope.

OK.

> > +      feature = tdesc_find_feature (tdesc, "org.gnu.gdb.rx.core");
> > +
> > +      if (feature != NULL)
> > +	{
> > +	  tdesc_data = tdesc_data_alloc ();
> > +	  valid_p = 1;
> > +	  for (i = 0; i < RX_NUM_REGS; i++)
> > +	    valid_p &= tdesc_numbered_register (feature, tdesc_data, i,
> > +                                            rx_register_names[i]);
> > +	}
> > +
> > +      if (!valid_p)
> > +	{
> > +	  tdesc_data_cleanup (tdesc_data);
> > +	  return NULL;
> > +	}
> > +    }
> > +
> >    tdep = XCNEW (struct gdbarch_tdep);
> >    gdbarch = gdbarch_alloc (&info, tdep);
> >    tdep->elf_flags = elf_flags;
> > @@ -1083,15 +1103,6 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> >    set_gdbarch_sw_breakpoint_from_kind (gdbarch, rx_breakpoint::bp_from_kind);
> >    set_gdbarch_skip_prologue (gdbarch, rx_skip_prologue);
> >  
> > -  /* Target builtin data types.  */
> > -  set_gdbarch_char_signed (gdbarch, 0);
> > -  set_gdbarch_short_bit (gdbarch, 16);
> > -  set_gdbarch_int_bit (gdbarch, 32);
> > -  set_gdbarch_long_bit (gdbarch, 32);
> > -  set_gdbarch_long_long_bit (gdbarch, 64);
> > -  set_gdbarch_ptr_bit (gdbarch, 32);
> > -  set_gdbarch_float_bit (gdbarch, 32);
> > -  set_gdbarch_float_format (gdbarch, floatformats_ieee_single);
> 
> I don't understand why these are being deleted.  This doesn't feel
> like it should be related to conversion to target descriptions.

OK. Revert it.

> >    if (elf_flags & E_FLAG_RX_64BIT_DOUBLES)
> >      {
> >        set_gdbarch_double_bit (gdbarch, 64);
> > @@ -1115,6 +1126,8 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> >    dwarf2_append_unwinders (gdbarch);
> >    frame_unwind_append_unwinder (gdbarch, &rx_frame_unwind);
> >  
> > +  rx_register_g_packet_guesses (gdbarch);
> > +
> >    /* Methods setting up a dummy call, and extracting the return value from
> >       a call.  */
> >    set_gdbarch_push_dummy_call (gdbarch, rx_push_dummy_call);
> > @@ -1123,6 +1136,9 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> >    /* Virtual tables.  */
> >    set_gdbarch_vbit_in_delta (gdbarch, 1);
> >  
> > +  if (tdesc_data != NULL)
> > +    tdesc_use_registers (gdbarch, tdesc, tdesc_data);
> 
> I'm confused by the 'tdesc_data != NULL' check here, my reading of
> things is that either:
> 
>   1. Target doesn't provide a target description, we fall back to the
>   built in tdesc_rx, this will be valid, tdesc_data will not be NULL.
> 
>   2. The target provides a description, but its invalid, we bail out
>   earlier after the validity check, we never reach this code.
> 
>   3. The target provides a description which is valid, tdesc_data will
>   not be NULL.
> 
> I'd prefer to see a 'gdb_assert (tdesc_data != NULL)' immediately
> after the earlier 'if (!valid_p)' block, and then after that just
> assume tdesc_data is not NULL.

OK. 

> Actually, while we're moving code around, is there any reason that
> this call to tdesc_use_registers couldn't move up to be just after the
> valid_p check?  Given its closely related code?

Since target-description can always be used, I moved to the front.

> > +
> >    return gdbarch;
> >  }
> >  
> > @@ -1132,4 +1148,5 @@ void
> >  _initialize_rx_tdep (void)
> >  {
> >    register_gdbarch_init (bfd_arch_rx, rx_gdbarch_init);
> > +  initialize_tdesc_rx ();
> >  }
> > -- 
> > 2.11.0
> > 
> 
> Thanks,
> Andrew

I'll sent v2 patch.
Thanks.
  

Patch

diff --git a/gdb/features/Makefile b/gdb/features/Makefile
index 0c84faf405..2b65d46df0 100644
--- a/gdb/features/Makefile
+++ b/gdb/features/Makefile
@@ -161,6 +161,7 @@  XMLTOC = \
 	rs6000/powerpc-vsx64.xml \
 	rs6000/powerpc-vsx64l.xml \
 	rs6000/rs6000.xml \
+	rx.xml \
 	s390-linux32.xml \
 	s390-linux32v1.xml \
 	s390-linux32v2.xml \
@@ -238,6 +239,7 @@  FEATURE_XMLFILES = aarch64-core.xml \
 	riscv/64bit-cpu.xml \
 	riscv/64bit-csr.xml \
 	riscv/64bit-fpu.xml \
+	rx.xml \
 	tic6x-c6xp.xml \
 	tic6x-core.xml \
 	tic6x-gp.xml
diff --git a/gdb/features/rx.xml b/gdb/features/rx.xml
new file mode 100644
index 0000000000..b5aa9ac4a8
--- /dev/null
+++ b/gdb/features/rx.xml
@@ -0,0 +1,70 @@ 
+<?xml version="1.0"?>
+<!-- Copyright (C) 2019 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.rx.core">
+  <reg name="r0" bitsize="32" type="data_ptr"/>
+  <reg name="r1" bitsize="32" type="uint32"/>
+  <reg name="r2" bitsize="32" type="uint32"/>
+  <reg name="r3" bitsize="32" type="uint32"/>
+  <reg name="r4" bitsize="32" type="uint32"/>
+  <reg name="r5" bitsize="32" type="uint32"/>
+  <reg name="r6" bitsize="32" type="uint32"/>
+  <reg name="r7" bitsize="32" type="uint32"/>
+  <reg name="r8" bitsize="32" type="uint32"/>
+  <reg name="r9" bitsize="32" type="uint32"/>
+  <reg name="r10" bitsize="32" type="uint32"/>
+  <reg name="r11" bitsize="32" type="uint32"/>
+  <reg name="r12" bitsize="32" type="uint32"/>
+  <reg name="r13" bitsize="32" type="uint32"/>
+  <reg name="r14" bitsize="32" type="uint32"/>
+  <reg name="r15" bitsize="32" type="uint32"/>
+
+  <flags id="psw_flags" size="4">
+    <field name="C" start="0" end="0"/>
+    <field name="Z" start="1" end="1"/>
+    <field name="S" start="2" end="2"/>
+    <field name="O" start="3" end="3"/>
+    <field name="I" start="16" end="16"/>
+    <field name="U" start="17" end="17"/>
+    <field name="PM" start="20" end="20"/>
+    <field name="IPL" start="24" end="27"/>
+  </flags>
+
+  <flags id="fpsw_flags" size="4">
+    <field name="RM" start="0" end="1"/>
+    <field name="CV" start="2" end="2"/>
+    <field name="CO" start="3" end="3"/>
+    <field name="CZ" start="4" end="4"/>
+    <field name="CU" start="5" end="5"/>
+    <field name="CX" start="6" end="6"/>
+    <field name="CE" start="7" end="7"/>
+    <field name="DN" start="8" end="8"/>
+    <field name="EV" start="10" end="10"/>
+    <field name="EO" start="11" end="11"/>
+    <field name="EZ" start="12" end="12"/>
+    <field name="EU" start="13" end="13"/>
+    <field name="EX" start="14" end="14"/>
+    <field name="FV" start="26" end="26"/>
+    <field name="FO" start="27" end="27"/>
+    <field name="FZ" start="28" end="28"/>
+    <field name="FU" start="29" end="29"/>
+    <field name="FX" start="30" end="30"/>
+    <field name="FS" start="31" end="31"/>
+  </flags>
+
+  <reg name="usp" bitsize="32" type="data_ptr"/>
+  <reg name="isp" bitsize="32" type="data_ptr"/>
+  <reg name="psw" bitsize="32" type="psw_flags"/>
+  <reg name="pc" bitsize="32" type="code_ptr"/>
+  <reg name="intb" bitsize="32" type="data_ptr"/>
+  <reg name="bpsw" bitsize="32" type="psw_flags"/>
+  <reg name="bpc" bitsize="32" type="code_ptr"/>
+  <reg name="fintv" bitsize="32" type="code_ptr"/>
+  <reg name="fpsw" bitsize="32" type="fpsw_flags"/>
+  <reg name="acc" bitsize="64" type="uint64"/>
+</feature>
diff --git a/gdb/rx-tdep.c b/gdb/rx-tdep.c
index 4cbf919db9..b3398f122a 100644
--- a/gdb/rx-tdep.c
+++ b/gdb/rx-tdep.c
@@ -33,11 +33,15 @@ 
 #include "value.h"
 #include "gdbcore.h"
 #include "dwarf2-frame.h"
+#include "remote.h"
+#include "target-descriptions.h"
 
 #include "elf/rx.h"
 #include "elf-bfd.h"
 #include <algorithm>
 
+#include "features/rx.c"
+
 /* Certain important register numbers.  */
 enum
 {
@@ -114,40 +118,21 @@  struct rx_prologue
   int reg_offset[RX_NUM_REGS];
 };
 
+static const char *const rx_register_names[] = {
+  "r0",  "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
+  "r8",  "r9",  "r10", "r11", "r12", "r13", "r14", "r15",
+  "usp", "isp", "psw", "pc",  "intb", "bpsw","bpc","fintv",
+  "fpsw", "acc",
+};
+
 /* Implement the "register_name" gdbarch method.  */
 static const char *
 rx_register_name (struct gdbarch *gdbarch, int regnr)
 {
-  static const char *const reg_names[] = {
-    "r0",
-    "r1",
-    "r2",
-    "r3",
-    "r4",
-    "r5",
-    "r6",
-    "r7",
-    "r8",
-    "r9",
-    "r10",
-    "r11",
-    "r12",
-    "r13",
-    "r14",
-    "r15",
-    "usp",
-    "isp",
-    "psw",
-    "pc",
-    "intb",
-    "bpsw",
-    "bpc",
-    "fintv",
-    "fpsw",
-    "acc"
-  };
-
-  return reg_names[regnr];
+  if (regnr >= 0 && regnr < RX_NUM_REGS)
+    return rx_register_names[regnr];
+  else
+    return NULL;
 }
 
 /* Construct the flags type for PSW and BPSW.  */
@@ -1037,6 +1022,14 @@  rx_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
     return -1;
 }
 
+static void
+rx_register_g_packet_guesses (struct gdbarch *gdbarch)
+{
+  register_remote_g_packet_guess (gdbarch,
+                                  4 * RX_NUM_REGS,
+                                  tdesc_rx);
+}
+
 /* Allocate and initialize a gdbarch object.  */
 static struct gdbarch *
 rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
@@ -1044,6 +1037,8 @@  rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   struct gdbarch *gdbarch;
   struct gdbarch_tdep *tdep;
   int elf_flags;
+  struct tdesc_arch_data *tdesc_data = NULL;
+  const struct target_desc *tdesc = info.target_desc;
 
   /* Extract the elf_flags if available.  */
   if (info.abfd != NULL
@@ -1065,8 +1060,33 @@  rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
       return arches->gdbarch;
     }
 
-  /* None found, create a new architecture from the information
-     provided.  */
+  if (tdesc == NULL)
+      tdesc = tdesc_rx;
+
+  /* Check any target description for validity.  */
+  if (tdesc_has_registers (tdesc))
+    {
+      const struct tdesc_feature *feature;
+      int valid_p = 0;
+      int i = 0;
+      feature = tdesc_find_feature (tdesc, "org.gnu.gdb.rx.core");
+
+      if (feature != NULL)
+	{
+	  tdesc_data = tdesc_data_alloc ();
+	  valid_p = 1;
+	  for (i = 0; i < RX_NUM_REGS; i++)
+	    valid_p &= tdesc_numbered_register (feature, tdesc_data, i,
+                                            rx_register_names[i]);
+	}
+
+      if (!valid_p)
+	{
+	  tdesc_data_cleanup (tdesc_data);
+	  return NULL;
+	}
+    }
+
   tdep = XCNEW (struct gdbarch_tdep);
   gdbarch = gdbarch_alloc (&info, tdep);
   tdep->elf_flags = elf_flags;
@@ -1083,15 +1103,6 @@  rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_sw_breakpoint_from_kind (gdbarch, rx_breakpoint::bp_from_kind);
   set_gdbarch_skip_prologue (gdbarch, rx_skip_prologue);
 
-  /* Target builtin data types.  */
-  set_gdbarch_char_signed (gdbarch, 0);
-  set_gdbarch_short_bit (gdbarch, 16);
-  set_gdbarch_int_bit (gdbarch, 32);
-  set_gdbarch_long_bit (gdbarch, 32);
-  set_gdbarch_long_long_bit (gdbarch, 64);
-  set_gdbarch_ptr_bit (gdbarch, 32);
-  set_gdbarch_float_bit (gdbarch, 32);
-  set_gdbarch_float_format (gdbarch, floatformats_ieee_single);
   if (elf_flags & E_FLAG_RX_64BIT_DOUBLES)
     {
       set_gdbarch_double_bit (gdbarch, 64);
@@ -1115,6 +1126,8 @@  rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   dwarf2_append_unwinders (gdbarch);
   frame_unwind_append_unwinder (gdbarch, &rx_frame_unwind);
 
+  rx_register_g_packet_guesses (gdbarch);
+
   /* Methods setting up a dummy call, and extracting the return value from
      a call.  */
   set_gdbarch_push_dummy_call (gdbarch, rx_push_dummy_call);
@@ -1123,6 +1136,9 @@  rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   /* Virtual tables.  */
   set_gdbarch_vbit_in_delta (gdbarch, 1);
 
+  if (tdesc_data != NULL)
+    tdesc_use_registers (gdbarch, tdesc, tdesc_data);
+
   return gdbarch;
 }
 
@@ -1132,4 +1148,5 @@  void
 _initialize_rx_tdep (void)
 {
   register_gdbarch_init (bfd_arch_rx, rx_gdbarch_init);
+  initialize_tdesc_rx ();
 }