[PATCH v3 1/3] gdb: Add OpenRISC or1k and or1knd target support

Luis Machado lgustavo@codesourcery.com
Fri Dec 23 21:21:00 GMT 2016


On 12/22/2016 10:14 AM, Stafford Horne wrote:
> From: Franck Jullien <franck.jullien@gmail.com>
>
> This patch prepates the current GDB port of the openrisc processor from
> https://github.com/openrisc/binutils-gdb for upstream merging.
>
> Testing has been done with a cgen sim provided in a separate patch. This
> has been tested with 2 toolchains. GCC [1] 5.4.0 from the openrisc
> project with Newlib [2] and GCC 5.4.0 with Musl [3] 1.1.4.
>
> It supports or1knd (no delay slot target).
> The default target is or1k (with delay slot).
>
> You can change the target arch with:
>
> (gdb) set architecture or1knd
> The target architecture is assumed to be or1knd
>
> [1] https://github.com/openrisc/or1k-gcc
> [2] https://github.com/openrisc/newlib
> [3] https://github.com/openrisc/musl-cross
>
> gdb/doc/ChangeLog:
>
> 2016-03-13  Stefan Wallentowitz  <stefan@wallentowitz.de>
> 	    Franck Jullien  <franck.jullien@gmail.com>
> 	    Jeremy Bennett  <jeremy.bennett@embecosm.com>
>
> 	* gdb.texinfo: Add OpenRISC documentation.
>
> gdb/ChangeLog:
>
> 2016-11-23  Stafford Horne  <shorne@gmail.com>
> 	    Stefan Wallentowitz  <stefan@wallentowitz.de>
> 	    Stefan Kristiansson  <stefan.kristiansson@saunalahti.fi>
> 	    Franck Jullien  <franck.jullien@gmail.com>
> 	    Jeremy Bennett  <jeremy.bennett@embecosm.com>
>
> 	* configure.tgt: Add targets for or1k and or1knd.
> 	* or1k-tdep.c: New.
> 	* or1k-tdep.h: New.
> ---
>  gdb/configure.tgt   |   12 +
>  gdb/doc/gdb.texinfo |   68 +++
>  gdb/or1k-tdep.c     | 1436 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  gdb/or1k-tdep.h     |   57 ++
>  4 files changed, 1573 insertions(+)
>  create mode 100644 gdb/or1k-tdep.c
>  create mode 100644 gdb/or1k-tdep.h
>
> diff --git a/gdb/configure.tgt b/gdb/configure.tgt
> index 3f2603d..40764c6 100644
> --- a/gdb/configure.tgt
> +++ b/gdb/configure.tgt
> @@ -421,6 +421,18 @@ nios2*-*-*)
>  	gdb_target_obs="nios2-tdep.o"
>  	;;
>
> +or1k-*-*)
> +	# Target: OpenCores OpenRISC 1000 32-bit implementation bare metal
> +	gdb_target_obs="or1k-tdep.o"
> +	gdb_sim=../sim/or1k/libsim.a
> +	;;
> +
> +or1knd-*-*)
> +	# Target: OpenCores OpenRISC 1000 32-bit implementation bare metal, without delay slot
> +	gdb_target_obs="or1k-tdep.o"
> +	gdb_sim=../sim/or1k/libsim.a
> +	;;
> +

I noticed both targets use the same files. Is there a reason why we need 
both and not a single entry that can be identified at runtime?

>  powerpc*-*-freebsd*)
>  	# Target: FreeBSD/powerpc
>  	gdb_target_obs="rs6000-tdep.o ppc-sysv-tdep.o ppc64-tdep.o \
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index a0de7d1..7ae33d1 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -541,6 +541,10 @@ Steve Tjiang, John Newlin, and Scott Foehner.
>  Michael Eager and staff of Xilinx, Inc., contributed support for the
>  Xilinx MicroBlaze architecture.
>
> +The original port to the OpenRISC 1000 is believed to be due to
> +Alessandro Forin and Per Bothner. More recent ports have been the work
> +of Jeremy Bennett.
> +
>  @node Sample Session
>  @chapter A Sample @value{GDBN} Session
>
> @@ -22022,6 +22026,7 @@ acceptable commands.
>  * M68K::                        Motorola M68K
>  * MicroBlaze::			Xilinx MicroBlaze
>  * MIPS Embedded::               MIPS Embedded
> +* OpenRISC 1000::               OpenRISC 1000 (or1k)
>  * PowerPC Embedded::            PowerPC Embedded
>  * AVR::                         Atmel AVR
>  * CRIS::                        CRIS
> @@ -22228,6 +22233,69 @@ As usual, you can inquire about the @code{mipsfpu} variable with
>  @samp{show mipsfpu}.
>  @end table
>
> +@node OpenRISC 1000
> +@subsection OpenRISC 1000
> +@cindex OpenRISC 1000
> +
> +Previous development versions of @value{GDBN} supported remote connection
> +via a proprietary JTAG protocol using the @samp{target jtag} command.
> +Support for this has now been dropped.
> +
> +Also, previous verions had support for a @samp{spr} command to access
> +OpenRISC's numberous special purpose registers.  These are now available
> +via the normal @samp{info registers} command.
> +
> +@table @code
> +
> +@kindex target remote
> +@item target remote
> +
> +This is now the only way to connect to a remote OpenRISC 1000
> +target.  This is supported by @dfn{Or1ksim}, the OpenRISC 1000
> +architectural simulator, Verilatorm and Icarus Verilog
> +simulations.  @dfn{Remote serial protocol} servers are also available to

Verilatorm and Icarus simulations or simulators?

> +drive various hardware implementations via JTAG.
> +Connects to remote JTAG server.
> +
> +Example: @code{target remote :51000}
> +
> +@kindex target sim
> +@item target sim
> +
> +Runs the builtin CPU simulator which can run very basic
> +programs, does not support most hardware functions like MMU.

"...programs but does not support..."?

> +However for more complex use, the user is advised to run and external

"... more complex use cases..."? Or maybe "... more complex uses..."?

> +target, and connect using @samp{target remote}
> +
> +Example: @code{target sim}
> +
> +@end table
> +
> +There are some known problems with the current implementation
> +@cindex OpenRISC 1000 known problems
> +
> +@enumerate
> +
> +@item
> +@cindex OpenRISC 1000 known problems, hardware breakpoints and watchpoints
> +Some OpenRISC 1000 targets support hardware breakpoints and watchpoints.
> +Consult the target documentation for details.  @value{GDBN} is not
> +perfect in handling of watchpoints.  It is possible to allocate hardware
> +watchpoints and not discover until running that sufficient watchpoints
> +are not available.  It is also possible that GDB will report watchpoints
> +being hit spuriously.  This can be down to the assembly code having
> +additional memory accesses that are not obviously reflected in the
> +source code.
> +
> +@item
> +@cindex OpenRISC 1000 known problems, architectural compatability

typo, compatibility.

> +The OpenRISC 1000 architecture has evolved since the first port of @value{GDBN}. In particular the structure of the Unit Present register has

"...first port FOR ..."

> +changed and the CPU Configuration register has been added.  The port of
> +@value{GDBN} version @value{GDBVN} uses the @emph{current}
> +specification of the OpenRISC 1000.
> +
> +@end enumerate
> +
>  @node PowerPC Embedded
>  @subsection PowerPC Embedded
>
> diff --git a/gdb/or1k-tdep.c b/gdb/or1k-tdep.c
> new file mode 100644
> index 0000000..d906066
> --- /dev/null
> +++ b/gdb/or1k-tdep.c
> @@ -0,0 +1,1436 @@
> +/* Target-dependent code for the 32-bit OpenRISC 1000, for the GDB.
> +   Copyright (C) 2008-2016, Free Software Foundation, Inc.
> +   Contributed by Alessandro Forin(af@cs.cmu.edu at CMU
> +   and by Per Bothner(bothner@cs.wisc.edu) at U.Wisconsin.
> +   Contributed by Jeremy Bennett <jeremy.bennett@embecosm.com>
> +   Contributed by Franck Jullien <franck.jullien@gmail.com> on behalf of
> +   Embecosm Limited
> +   Contributed by Stafford Horne <shorne@gmail.com>

I've seen recent reviews that point at not mentioning these 
contributions in the source code but rather in the documentation. So i 
think these should be moved somewhere else (maybe they have already been 
moved and you just forgot to remove the above?)

> +
> +   This file is part of GDB.
> +
> +   This program 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 of the License, or
> +   (at your option) any later version.
> +
> +   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, see <http://www.gnu.org/licenses/>.  */
> +
> +#include "defs.h"
> +#include "frame.h"
> +#include "inferior.h"
> +#include "symtab.h"
> +#include "value.h"
> +#include "gdbcmd.h"
> +#include "language.h"
> +#include "gdbcore.h"
> +#include "symfile.h"
> +#include "objfiles.h"
> +#include "gdbtypes.h"
> +#include "target.h"
> +#include "regcache.h"
> +#include "safe-ctype.h"
> +#include "block.h"
> +#include "reggroups.h"
> +#include "arch-utils.h"
> +#include "frame.h"
> +#include "frame-unwind.h"
> +#include "frame-base.h"
> +#include "dwarf2-frame.h"
> +#include "trad-frame.h"
> +#include "regset.h"
> +#include "remote.h"
> +#include "target-descriptions.h"
> +
> +#include <inttypes.h>
> +
> +#include "dis-asm.h"

Push these two includes up and together with the rest.

> +
> +/* OpenRISC specific includes.  */
> +#include "or1k-tdep.h"
> +

> +
> +/* The target-dependant structure for gdbarch.  */
> +
> +struct gdbarch_tdep
> +{
> +  int bytes_per_word;
> +  int bytes_per_address;
> +  CGEN_CPU_DESC gdb_cgen_cpu_desc;
> +};
> +
> +/* Support functions for the architecture definition.  */
> +
> +/* Get an instruction from memory.  */
> +
> +static ULONGEST
> +or1k_fetch_instruction (struct gdbarch *gdbarch, CORE_ADDR addr)
> +{
> +  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
> +  gdb_byte buf[OR1K_INSTLEN];
> +
> +  if (target_read_memory (addr, buf, OR1K_INSTLEN))
> +    {
> +      memory_error (TARGET_XFER_E_IO, addr);
> +    }
> +

No need for curly braces for single-statement conditional blocks.

> +  return extract_unsigned_integer (buf, OR1K_INSTLEN, byte_order);
> +
> +}
> +
> +

spurious newline.

> +/* Generic function to read bits from an instruction.  */
> +
> +static int
> +or1k_analyse_inst (uint32_t inst, const char *format, ...)
> +{
> +  /* Break out each field in turn, validating as we go.  */
> +  va_list ap;
> +
> +  int i;
> +  int iptr = 0;			/* Instruction pointer */
> +
> +  va_start (ap, format);
> +
> +  for (i = 0; 0 != format[i];)
> +    {
> +      const char *start_ptr;
> +      char *end_ptr;
> +
> +      uint32_t bits;		/* Bit substring of interest */
> +      uint32_t width;		/* Substring width */
> +      uint32_t *arg_ptr;
> +
> +      switch (format[i])
> +	{
> +	case ' ':
> +	  i++;
> +	  break;		/* Formatting: ignored */
> +
> +	case '0':
> +	case '1':		/* Constant bit field */
> +	  bits = (inst >> (OR1K_INSTBITLEN - iptr - 1)) & 0x1;
> +
> +	  if ((format[i] - '0') != bits)
> +	    {
> +	      return 0;
> +	    }

No need for curly braces. Possibly more occurrences of this.

Also, the identation seems a bit off. In special for some of the comments.

> +
> +	  iptr++;
> +	  i++;
> +	  break;
> +
> +	case '%':		/* Bit field */
> +	  i++;
> +	  start_ptr = &(format[i]);
> +	  width = strtoul (start_ptr, &end_ptr, 10);
> +
> +	  /* Check we got something, and if so skip on */

period and two spaces after end of comment. More occurrences of this 
throughout.

> +	  if (start_ptr == end_ptr)
> +	    {
> +	      throw_quit
> +		("bitstring \"%s\" at offset %d has no length field.\n",
> +		 format, i);
> +	    }
> +
> +	  i += end_ptr - start_ptr;
> +
> +	  /* Look for and skip the terminating 'b'. If it's not there, we
> +	     still give a fatal error, because these are fixed strings that
> +	     just should not be wrong.  */

Two spaces after period. More occurrences throughout.


> +	  if ('b' != format[i++])
> +	    {
> +	      throw_quit
> +		("bitstring \"%s\" at offset %d has no terminating 'b'.\n",
> +		 format, i);
> +	    }
> +
> +	  /* Break out the field. There is a special case with a bit width of
> +	     32.  */
> +	  if (32 == width)
> +	    {
> +	      bits = inst;
> +	    }
> +	  else
> +	    {
> +	      bits =
> +		(inst >> (OR1K_INSTBITLEN - iptr - width)) & ((1 << width) -
> +							      1);
> +	    }
> +
> +	  arg_ptr = va_arg (ap, uint32_t *);
> +	  *arg_ptr = bits;
> +	  iptr += width;
> +	  break;
> +
> +	default:
> +	  throw_quit ("invalid character in bitstring \"%s\" at offset %d.\n",
> +		      format, i);
> +	  break;
> +	}
> +    }
> +
> +  /* Is the length OK? */
> +  gdb_assert (OR1K_INSTBITLEN == iptr);
> +
> +  return 1; /* We succeeded */
> +

Spurious newline. Possibly more occurrences throughout

> +}
> +
> +
> +/* Analyse a l.addi instruction in form: l.addi  rD,rA,I. This is used
> +   to parse add instructions during various prologue analysis routines.  */
> +
> +static int
> +or1k_analyse_l_addi (uint32_t inst,
> +		     unsigned int *rd_ptr,
> +		     unsigned int *ra_ptr, int *simm_ptr)
> +{
> +  /* Instruction fields */
> +  uint32_t rd, ra, i;
> +
> +  if (or1k_analyse_inst (inst, "10 0111 %5b %5b %16b", &rd, &ra, &i))
> +    {
> +      /* Found it. Construct the result fields.  */
> +      *rd_ptr = (unsigned int) rd;
> +      *ra_ptr = (unsigned int) ra;

Do we need these explicit cast or can we use types that make the casts 
go away?

> +      *simm_ptr = (int) (((i & 0x8000) == 0x8000) ? 0xffff0000 | i : i);
> +
> +      return 1;		/* Success */
> +    }
> +  else
> +    {
> +      return 0;		/* Failure */
> +    }
> +}
> +
> +
> +/* Analyse a l.sw instruction in form: l.sw  I(rA),rB. This is used to
> +   to parse store instructions during various prologue analysis routines.  */
> +
> +static int
> +or1k_analyse_l_sw (uint32_t inst,
> +		   int *simm_ptr, unsigned int *ra_ptr, unsigned int *rb_ptr)
> +{
> +  /* Instruction fields */
> +  uint32_t ihi, ilo, ra, rb;
> +
> +  if (or1k_analyse_inst (inst, "11 0101 %5b %5b %5b %11b", &ihi, &ra, &rb,
> +			 &ilo))
> +
> +    {
> +      /* Found it. Construct the result fields.  */
> +      *simm_ptr = (int) ((ihi << 11) | ilo);
> +      *simm_ptr |= ((ihi & 0x10) == 0x10) ? 0xffff0000 : 0;
> +
> +      *ra_ptr = (unsigned int) ra;
> +      *rb_ptr = (unsigned int) rb;
> +
> +      return 1;		/* Success */
> +    }
> +  else
> +    {
> +      return 0;		/* Failure */
> +    }
> +}
> +

> +
> +/* Functions defining the architecture.  */
> +
> +/* Implement the return_value gdbarch method.  */
> +
> +static enum return_value_convention
> +or1k_return_value (struct gdbarch *gdbarch, struct value *functype,
> +		   struct type *valtype, struct regcache *regcache,
> +		   gdb_byte *readbuf, const gdb_byte *writebuf)
> +{
> +  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
> +  enum type_code rv_type = TYPE_CODE (valtype);
> +  unsigned int rv_size = TYPE_LENGTH (valtype);
> +  unsigned int bpw = (gdbarch_tdep (gdbarch))->bytes_per_word;
> +
> +  /* Deal with struct/union as addresses. If an array won't fit in a single
> +     register it is returned as address. Anything larger than 2 registers needs
> +     to also be passed as address (matches gcc default_return_in_memory).  */
> +  if ((TYPE_CODE_STRUCT == rv_type) || (TYPE_CODE_UNION == rv_type)
> +      || ((TYPE_CODE_ARRAY == rv_type) && (rv_size > bpw))
> +      || (rv_size > 2 * bpw))
> +    {
> +      if (readbuf != NULL)
> +	{
> +	  ULONGEST tmp;
> +
> +	  regcache_cooked_read_unsigned (regcache, OR1K_RV_REGNUM, &tmp);
> +	  read_memory (tmp, readbuf, rv_size);
> +	}
> +      if (writebuf != NULL)
> +	{
> +	  ULONGEST tmp;
> +
> +	  regcache_cooked_read_unsigned (regcache, OR1K_RV_REGNUM, &tmp);
> +	  write_memory (tmp, writebuf, rv_size);
> +	}
> +
> +      return RETURN_VALUE_ABI_RETURNS_ADDRESS;
> +    }
> +
> +  if (rv_size <= bpw)
> +    {
> +      /* Up to one word scalars are returned in R11.  */
> +      if (readbuf != NULL)
> +	{
> +	  ULONGEST tmp;
> +
> +	  regcache_cooked_read_unsigned (regcache, OR1K_RV_REGNUM, &tmp);
> +	  store_unsigned_integer (readbuf, rv_size, byte_order, tmp);
> +
> +	}
> +      if (writebuf != NULL)
> +	{
> +	  gdb_byte buf[4];
> +	  memset (buf, 0, sizeof (buf)); /* Zero pad if < bpw bytes */
> +
> +	  if (BFD_ENDIAN_BIG == byte_order)
> +	    {
> +	      memcpy (buf + sizeof (buf) - rv_size, writebuf, rv_size);
> +	    }
> +	  else
> +	    {
> +	      memcpy (buf, writebuf, rv_size);
> +	    }
> +
> +	  regcache_cooked_write (regcache, OR1K_RV_REGNUM, buf);
> +	}
> +    }
> +  else
> +    {
> +      /* 2 word scalars are returned in r11/r12 (with the MS word in r11).  */
> +      if (readbuf != NULL)
> +	{
> +	  ULONGEST tmp_lo;
> +	  ULONGEST tmp_hi;
> +	  ULONGEST tmp;
> +
> +	  regcache_cooked_read_unsigned (regcache, OR1K_RV_REGNUM, &tmp_hi);
> +	  regcache_cooked_read_unsigned (regcache, OR1K_RV_REGNUM + 1,
> +					 &tmp_lo);
> +	  tmp = (tmp_hi << (bpw * 8)) | tmp_lo;
> +
> +	  store_unsigned_integer (readbuf, rv_size, byte_order, tmp);
> +	}
> +      if (writebuf != NULL)
> +	{
> +	  gdb_byte buf_lo[4];
> +	  gdb_byte buf_hi[4];
> +
> +	  memset (buf_lo, 0, sizeof (buf_lo));	/* Zero pad if < bpw bytes */
> +	  memset (buf_hi, 0, sizeof (buf_hi));	/* Zero pad if < bpw bytes */
> +
> +	  /* This is cheating. We assume that we fit in 2 words exactly, which
> +	     wouldn't work if we had (say) a 6-byte scalar type on a big
> +	     endian architecture (with the OpenRISC 1000 usually is).  */
> +	  memcpy (buf_hi, writebuf, rv_size - bpw);
> +	  memcpy (buf_lo, writebuf + bpw, bpw);
> +
> +	  regcache_cooked_write (regcache, OR1K_RV_REGNUM, buf_hi);
> +	  regcache_cooked_write (regcache, OR1K_RV_REGNUM + 1, buf_lo);
> +	}
> +    }
> +
> +  return RETURN_VALUE_REGISTER_CONVENTION;
> +
> +}
> +
> +/* OR1K always uses a l.trap instruction for breakpoints.  */
> +
> +constexpr gdb_byte or1k_break_insn[] = {0x21, 0x00, 0x00, 0x01};
> +
> +typedef BP_MANIPULATION (or1k_break_insn) or1k_breakpoint;
> +
> +/* Implement the single_step_through_delay gdbarch method  */
> +
> +static int
> +or1k_single_step_through_delay (struct gdbarch *gdbarch,
> +				struct frame_info *this_frame)
> +{
> +  ULONGEST val;
> +  CORE_ADDR ppc;
> +  CORE_ADDR npc;
> +  CGEN_FIELDS tmp_fields;
> +  const CGEN_INSN *insns;
> +  struct regcache *regcache = get_current_regcache ();
> +  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +
> +  /* Get and the previous and current instruction addresses. If they are not
> +     adjacent, we cannot be in a delay slot. */
> +  regcache_cooked_read_unsigned (regcache, OR1K_PPC_REGNUM, &val);
> +  ppc = (CORE_ADDR) val;
> +  regcache_cooked_read_unsigned (regcache, OR1K_NPC_REGNUM, &val);
> +  npc = (CORE_ADDR) val;
> +
> +  if (0x4 != (npc - ppc))
> +    {
> +      return 0;
> +    }
> +
> +  insns = cgen_lookup_insn (tdep->gdb_cgen_cpu_desc,
> +			    NULL,
> +			    or1k_fetch_instruction (gdbarch, ppc),
> +			    NULL, 32, &tmp_fields, 0);
> +
> +  /* TODO: we should add a delay slot flag to the CGEN_INSN and remove
> +   * this hard coded test. */
> +  return ((CGEN_INSN_NUM (insns) == OR1K_INSN_L_J)
> +	  || (CGEN_INSN_NUM (insns) == OR1K_INSN_L_JAL)
> +	  || (CGEN_INSN_NUM (insns) == OR1K_INSN_L_JR)
> +	  || (CGEN_INSN_NUM (insns) == OR1K_INSN_L_JALR)
> +	  || (CGEN_INSN_NUM (insns) == OR1K_INSN_L_BNF)
> +	  || (CGEN_INSN_NUM (insns) == OR1K_INSN_L_BF));
> +
> +}
> +
> +/* Name for or1k general registers.  */
> +
> +static const char *const or1k_reg_names[OR1K_NUM_REGS] = {
> +  /* general purpose registers */
> +  "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
> +  "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
> +  "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
> +  "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
> +
> +  /* previous program counter, next program counter and status register */
> +  "ppc", "npc", "sr"
> +};
> +
> +/* Implement the register_name gdbarch method.  */
> +
> +static const char *
> +or1k_register_name (struct gdbarch *gdbarch, int regnum)
> +{
> +  if (0 <= regnum && regnum < OR1K_NUM_REGS)
> +    {
> +      return or1k_reg_names[regnum];
> +    }
> +  else
> +      return NULL;
> +}
> +
> +/* Implement the register_type gdbarch method.  */
> +
> +static struct type *
> +or1k_register_type (struct gdbarch *gdbarch, int regnum)
> +{
> +  if ((regnum >= 0) && (regnum < OR1K_NUM_REGS))
> +    {
> +      switch (regnum)
> +	{
> +	case OR1K_PPC_REGNUM:
> +	case OR1K_NPC_REGNUM:
> +	  return builtin_type (gdbarch)->builtin_func_ptr;	/* Pointer to code */
> +
> +	case OR1K_SP_REGNUM:
> +	case OR1K_FP_REGNUM:
> +	  return builtin_type (gdbarch)->builtin_data_ptr;	/* Pointer to data */
> +
> +	default:
> +	  return builtin_type (gdbarch)->builtin_uint32;	/* Data */
> +	}
> +    }
> +
> +  internal_error (__FILE__, __LINE__,
> +		  _("or1k_register_type: illegal register number %d"),
> +		  regnum);
> +
> +}
> +
> +/* Implement the register_reggroup_p gdbarch method.  */
> +
> +static int
> +or1k_register_reggroup_p (struct gdbarch *gdbarch,
> +			  int regnum, struct reggroup *group)
> +{
> +  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +
> +  /* All register group */
> +  if (group == all_reggroup)
> +    {
> +      return ((regnum >= 0)
> +	      && (regnum < OR1K_NUM_REGS)
> +	      && (or1k_register_name (gdbarch, regnum)[0] != '\0'));
> +    }
> +
> +  /* For now everything except the PC */
> +  if (group == general_reggroup)
> +    {
> +      return ((regnum >= OR1K_ZERO_REGNUM)
> +	      && (regnum < OR1K_MAX_GPR_REGS)
> +	      && (regnum != OR1K_PPC_REGNUM) && (regnum != OR1K_NPC_REGNUM));
> +    }
> +
> +  if (group == float_reggroup)
> +    {
> +      return 0;	/* No float regs.  */
> +    }
> +
> +  if (group == vector_reggroup)
> +    {
> +      return 0;	/* No vector regs.  */
> +    }
> +
> +  /* For any that are not handled above.  */
> +  return default_register_reggroup_p (gdbarch, regnum, group);
> +
> +}
> +
> +
> +static int
> +or1k_is_arg_reg (unsigned int regnum)
> +{
> +  return (OR1K_FIRST_ARG_REGNUM <= regnum)
> +    && (regnum <= OR1K_LAST_ARG_REGNUM);
> +
> +}
> +
> +
> +static int
> +or1k_is_callee_saved_reg (unsigned int regnum)
> +{
> +  return (OR1K_FIRST_SAVED_REGNUM <= regnum) && (0 == regnum % 2);
> +
> +}
> +
> +
> +/* Implement the skip_prologue gdbarch method.  */
> +
> +static CORE_ADDR
> +or1k_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
> +{
> +  CORE_ADDR start_pc;
> +  CORE_ADDR addr;
> +  uint32_t inst;
> +
> +  unsigned int ra, rb, rd; /* for instruction analysis */
> +  int simm;
> +
> +  int frame_size = 0;
> +
> +  /* Try using SAL first if we have symbolic information available. This only
> +     works for DWARF 2, not STABS.  */
> +
> +  if (find_pc_partial_function (pc, NULL, &start_pc, NULL))
> +    {
> +      CORE_ADDR prologue_end = skip_prologue_using_sal (gdbarch, pc);
> +
> +      if (0 != prologue_end)
> +	{
> +	  struct symtab_and_line prologue_sal = find_pc_line (start_pc, 0);
> +	  struct compunit_symtab *compunit
> +	    = SYMTAB_COMPUNIT (prologue_sal.symtab);
> +	  const char *debug_format = COMPUNIT_DEBUGFORMAT (compunit);
> +
> +	  if ((NULL != debug_format)
> +	      && (strlen ("dwarf") <= strlen (debug_format))
> +	      && (0 == strncasecmp ("dwarf", debug_format, strlen ("dwarf"))))
> +	    {
> +	      return (prologue_end > pc) ? prologue_end : pc;
> +	    }
> +	}
> +    }
> +
> +  /* Look to see if we can find any of the standard prologue sequence. All
> +     quite difficult, since any or all of it may be missing. So this is just a
> +     best guess!  */
> +
> +  addr = pc; /* Where we have got to */
> +  inst = or1k_fetch_instruction (gdbarch, addr);
> +
> +  /* Look for the new stack pointer being set up.  */
> +  if (or1k_analyse_l_addi (inst, &rd, &ra, &simm)
> +      && (OR1K_SP_REGNUM == rd) && (OR1K_SP_REGNUM == ra)
> +      && (simm < 0) && (0 == (simm % 4)))
> +    {
> +      frame_size = -simm;
> +      addr += OR1K_INSTLEN;
> +      inst = or1k_fetch_instruction (gdbarch, addr);
> +    }
> +
> +  /* Look for the frame pointer being manipulated.  */
> +  if (or1k_analyse_l_sw (inst, &simm, &ra, &rb)
> +      && (OR1K_SP_REGNUM == ra) && (OR1K_FP_REGNUM == rb)
> +      && (simm >= 0) && (0 == (simm % 4)))
> +    {
> +      addr += OR1K_INSTLEN;
> +      inst = or1k_fetch_instruction (gdbarch, addr);
> +
> +      gdb_assert (or1k_analyse_l_addi (inst, &rd, &ra, &simm)
> +		  && (OR1K_FP_REGNUM == rd) && (OR1K_SP_REGNUM == ra)
> +		  && (simm == frame_size));
> +
> +      addr += OR1K_INSTLEN;
> +      inst = or1k_fetch_instruction (gdbarch, addr);
> +    }
> +
> +  /* Look for the link register being saved.  */
> +  if (or1k_analyse_l_sw (inst, &simm, &ra, &rb)
> +      && (OR1K_SP_REGNUM == ra) && (OR1K_LR_REGNUM == rb)
> +      && (simm >= 0) && (0 == (simm % 4)))
> +    {
> +      addr += OR1K_INSTLEN;
> +      inst = or1k_fetch_instruction (gdbarch, addr);
> +    }
> +
> +  /* Look for arguments or callee-saved register being saved. The register
> +     must be one of the arguments (r3-r8) or the 10 callee saved registers
> +     (r10, r12, r14, r16, r18, r20, r22, r24, r26, r28, r30). The base
> +     register must be the FP (for the args) or the SP (for the callee_saved
> +     registers).  */
> +  while (1)
> +    {
> +      if (or1k_analyse_l_sw (inst, &simm, &ra, &rb)
> +	  && (((OR1K_FP_REGNUM == ra) && or1k_is_arg_reg (rb))
> +	      || ((OR1K_SP_REGNUM == ra) && or1k_is_callee_saved_reg (rb)))
> +	  && (0 == (simm % 4)))
> +	{
> +	  addr += OR1K_INSTLEN;
> +	  inst = or1k_fetch_instruction (gdbarch, addr);
> +	}
> +      else
> +	{
> +	  /* Nothing else to look for. We have found the end of the prologue. */
> +	  return addr;
> +	}
> +    }
> +}
> +
> +
> +/* Implement the frame_align gdbarch method.  */
> +
> +static CORE_ADDR
> +or1k_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
> +{
> +  return align_down (sp, OR1K_STACK_ALIGN);
> +
> +}
> +
> +/* Implement the unwind_pc gdbarch method.  */
> +
> +static CORE_ADDR
> +or1k_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
> +{
> +  CORE_ADDR pc;
> +
> +  if (frame_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog, "or1k_unwind_pc, next_frame=%d\n",
> +			  frame_relative_level (next_frame));
> +    }
> +
> +  pc = frame_unwind_register_unsigned (next_frame, OR1K_NPC_REGNUM);
> +
> +  if (frame_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog, "or1k_unwind_pc, pc=0x%p\n",
> +			  (void *) pc);
> +    }
> +
> +  return pc;
> +
> +}
> +
> +/* Implement the unwind_sp gdbarch method.  */
> +
> +static CORE_ADDR
> +or1k_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
> +{
> +  CORE_ADDR sp;
> +
> +  if (frame_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog, "or1k_unwind_sp, next_frame=%d\n",
> +			  frame_relative_level (next_frame));
> +    }
> +
> +  sp = frame_unwind_register_unsigned (next_frame, OR1K_SP_REGNUM);
> +
> +  if (frame_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog, "or1k_unwind_sp, sp=0x%p\n",
> +			  (void *) sp);
> +    }
> +
> +  return sp;
> +
> +}
> +
> +/* Implement the push_dummy_code gdbarch method.  */
> +
> +static CORE_ADDR
> +or1k_push_dummy_code (struct gdbarch *gdbarch, CORE_ADDR sp,
> +		      CORE_ADDR function, struct value **args, int nargs,
> +		      struct type *value_type, CORE_ADDR * real_pc,
> +		      CORE_ADDR * bp_addr, struct regcache *regcache)
> +{
> +  CORE_ADDR bp_slot;
> +
> +  /* Reserve enough room on the stack for our breakpoint instruction.  */
> +  bp_slot = sp - 4;
> +  /* Store the address of that breakpoint.  */
> +  *bp_addr = bp_slot;
> +  /* keeping the stack aligned.  */
> +  sp = or1k_frame_align (gdbarch, bp_slot);
> +  /* The call starts at the callee's entry point.  */
> +  *real_pc = function;
> +
> +  return sp;
> +
> +}
> +
> +/* Implement the push_dummy_call gdbarch method.  */
> +
> +static CORE_ADDR
> +or1k_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
> +		      struct regcache *regcache, CORE_ADDR bp_addr,
> +		      int nargs, struct value **args, CORE_ADDR sp,
> +		      int struct_return, CORE_ADDR struct_addr)
> +{
> +
> +  int argreg;
> +  int argnum;
> +  int first_stack_arg;
> +  int stack_offset = 0;
> +  int heap_offset = 0;
> +  CORE_ADDR heap_sp = sp - 128;
> +  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
> +  unsigned int bpa = (gdbarch_tdep (gdbarch))->bytes_per_address;
> +  unsigned int bpw = (gdbarch_tdep (gdbarch))->bytes_per_word;
> +  struct type *func_type = value_type (function);
> +
> +  /* Return address */
> +  regcache_cooked_write_unsigned (regcache, OR1K_LR_REGNUM, bp_addr);
> +
> +  /* Register for the next argument.  */
> +  argreg = OR1K_FIRST_ARG_REGNUM;
> +
> +  /* Location for a returned structure. This is passed as a silent first
> +     argument.  */
> +  if (struct_return)
> +    {
> +      regcache_cooked_write_unsigned (regcache, OR1K_FIRST_ARG_REGNUM,
> +				      struct_addr);
> +      argreg++;
> +    }
> +
> +  /* Put as many args as possible in registers */
> +  for (argnum = 0; argnum < nargs; argnum++)
> +    {
> +      const gdb_byte *val;
> +      gdb_byte valbuf[sizeof (ULONGEST)];
> +
> +      struct value *arg = args[argnum];
> +      struct type *arg_type = check_typedef (value_type (arg));
> +      int len = arg_type->length;
> +      enum type_code typecode = arg_type->main_type->code;
> +
> +      if (TYPE_VARARGS (func_type) && argnum >= TYPE_NFIELDS (func_type))
> +	{
> +	  break; /* end or regular args, varargs go to stack */
> +	}
> +
> +      /* Extract the value, either a reference or the data */
> +      if ((TYPE_CODE_STRUCT == typecode) || (TYPE_CODE_UNION == typecode)
> +	  || (len > bpw * 2))
> +	{
> +	  CORE_ADDR valaddr = value_address (arg);
> +
> +	  /* if the arg is fabricated (i.e. 3*i, instead of i) valaddr is undefined */
> +	  if (valaddr == 0)
> +	    {
> +	      /* The argument needs to be copied into the target space. Since
> +	         the bottom of the stack is reserved for function arguments
> +	         we store this at the these at the top growing down.  */
> +	      heap_offset += align_up (len, bpw);
> +	      valaddr = heap_sp + heap_offset;
> +
> +	      write_memory (valaddr, value_contents (arg), len);
> +	    }
> +
> +	  /* The ABI passes all structures by reference, so get its address.  */
> +	  store_unsigned_integer (valbuf, bpa, byte_order, valaddr);
> +	  len = bpa;
> +	  val = valbuf;
> +	}
> +      else
> +	{
> +	  /* Everything else, we just get the value. */
> +	  val = value_contents (arg);
> +	}
> +
> +      /* Stick the value in a register */
> +      if (len > bpw)
> +	{
> +	  /* Big scalars use two registers, but need NOT be pair aligned.  */
> +
> +	  if (argreg <= (OR1K_LAST_ARG_REGNUM - 1))
> +	    {
> +	      ULONGEST regval =	extract_unsigned_integer (val, len, byte_order);
> +
> +	      unsigned int bits_per_word = bpw * 8;
> +	      ULONGEST mask = (((ULONGEST) 1) << bits_per_word) - 1;
> +	      ULONGEST lo = regval & mask;
> +	      ULONGEST hi = regval >> bits_per_word;
> +
> +	      regcache_cooked_write_unsigned (regcache, argreg, hi);
> +	      regcache_cooked_write_unsigned (regcache, argreg + 1, lo);
> +	      argreg += 2;
> +	    }
> +	  else
> +	    {
> +	      /* Run out of regs */
> +	      break;
> +	    }
> +	}
> +      else if (argreg <= OR1K_LAST_ARG_REGNUM)
> +	{
> +	  /* Smaller scalars fit in a single register */
> +	  regcache_cooked_write_unsigned (regcache, argreg,
> +					  extract_unsigned_integer (val, len,
> +								    byte_order));
> +	  argreg++;
> +	}
> +      else
> +	{
> +	  /* Run out of regs */
> +	  break;
> +	}
> +    }
> +
> +  first_stack_arg = argnum;
> +
> +  /* If we get here with argnum < nargs, then arguments remain to be placed on
> +     the stack. This is tricky, since they must be pushed in reverse order and
> +     the stack in the end must be aligned. The only solution is to do it in
> +     two stages, the first to compute the stack size, the second to save the
> +     args.  */
> +
> +  for (argnum = first_stack_arg; argnum < nargs; argnum++)
> +    {
> +      struct value *arg = args[argnum];
> +      struct type *arg_type = check_typedef (value_type (arg));
> +      int len = arg_type->length;
> +      enum type_code typecode = arg_type->main_type->code;
> +
> +      if ((TYPE_CODE_STRUCT == typecode) || (TYPE_CODE_UNION == typecode)
> +	  || (len > bpw * 2))
> +	{
> +	  /* Structures are passed as addresses */
> +	  sp -= bpa;
> +	}
> +      else
> +	{
> +	  /* Big scalars use more than one word. Code here allows for future
> +	     quad-word entities (e.g. long double) */
> +	  sp -= align_up (len, bpw);
> +	}
> +
> +      /* ensure our dummy heap doesn't touch the stack, this could only happen
> +         if we have many arguments including fabricated arguments */
> +      gdb_assert (heap_offset == 0 || ((heap_sp + heap_offset) < sp));
> +    }
> +
> +  sp = gdbarch_frame_align (gdbarch, sp);
> +  stack_offset = 0;
> +
> +  /* Push the remaining args on the stack */
> +  for (argnum = first_stack_arg; argnum < nargs; argnum++)
> +    {
> +      const gdb_byte *val;
> +      gdb_byte valbuf[sizeof (ULONGEST)];
> +
> +      struct value *arg = args[argnum];
> +      struct type *arg_type = check_typedef (value_type (arg));
> +      int len = arg_type->length;
> +      enum type_code typecode = arg_type->main_type->code;
> +      /* The EABI passes structures that do not fit in a register by
> +         reference. In all other cases, pass the structure by value.  */
> +      if ((TYPE_CODE_STRUCT == typecode) || (TYPE_CODE_UNION == typecode)
> +	  || (len > bpw * 2))
> +	{
> +	  store_unsigned_integer (valbuf, bpa, byte_order,
> +				  value_address (arg));
> +	  len = bpa;
> +	  val = valbuf;
> +	}
> +      else
> +	{
> +	  val = value_contents (arg);
> +	}
> +
> +      while (len > 0)
> +	{
> +	  int partial_len = (len < bpw ? len : bpw);
> +
> +	  write_memory (sp + stack_offset, val, partial_len);
> +	  stack_offset += align_up (partial_len, bpw);
> +	  len -= partial_len;
> +	  val += partial_len;
> +	}
> +    }
> +
> +  /* Save the updated stack pointer */
> +  regcache_cooked_write_unsigned (regcache, OR1K_SP_REGNUM, sp);
> +
> +  if (heap_offset > 0)
> +    {
> +      sp = heap_sp;
> +    }
> +
> +  return sp;
> +
> +}
> +
> +
> +/* Implement the dummy_id gdbarch method.  */
> +
> +static struct frame_id
> +or1k_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
> +{
> +  return frame_id_build (get_frame_sp (this_frame),
> +			 get_frame_pc (this_frame));
> +
> +}
> +

> +
> +
> +
> +/* Support functions for frame handling */
> +
> +/* Initialize a prologue cache
> +
> +   We build a cache, saying where registers of the PREV frame can be found
> +   from the data so far set up in this THIS.
> +
> +   We also compute a unique ID for this frame, based on the function start
> +   address and the stack pointer (as it will be, even if it has yet to be
> +   computed.
> +
> +   STACK FORMAT
> +   ============
> +
> +   The OR1K has a falling stack frame and a simple prolog. The Stack pointer
> +   is R1 and the frame pointer R2. The frame base is therefore the address
> +   held in R2 and the stack pointer (R1) is the frame base of the NEXT frame.
> +
> +   l.addi  r1,r1,-frame_size	# SP now points to end of new stack frame
> +
> +   The stack pointer may not be set up in a frameless function (e.g. a simple
> +   leaf function).
> +
> +   l.sw    fp_loc(r1),r2        # old FP saved in new stack frame
> +   l.addi  r2,r1,frame_size     # FP now points to base of new stack frame
> +
> +   The frame pointer is not necessarily saved right at the end of the stack
> +   frame - OR1K saves enough space for any args to called functions right at
> +   the end (this is a difference from the Architecture Manual).
> +
> +   l.sw    lr_loc(r1),r9        # Link (return) address
> +
> +   The link register is usally saved at fp_loc - 4. It may not be saved at all
> +   in a leaf function.
> +
> +   l.sw    reg_loc(r1),ry       # Save any callee saved regs
> +
> +   The offsets x for the callee saved registers generally (always?) rise in
> +   increments of 4, starting at fp_loc + 4. If the frame pointer is omitted
> +   (an option to GCC), then it may not be saved at all. There may be no callee
> +   saved registers.
> +
> +   So in summary none of this may be present. However what is present seems
> +   always to follow this fixed order, and occur before any substantive code
> +   (it is possible for GCC to have more flexible scheduling of the prologue,
> +   but this does not seem to occur for OR1K).
> +
> +   ANALYSIS
> +   ========
> +
> +   This prolog is used, even for -O3 with GCC.
> +
> +   All this analysis must allow for the possibility that the PC is in the
> +   middle of the prologue. Data in the cache should only be set up insofar as
> +   it has been computed.
> +
> +   HOWEVER. The frame_id must be created with the SP *as it will be* at the
> +   end of the Prologue. Otherwise a recursive call, checking the frame with
> +   the PC at the start address will end up with the same frame_id as the
> +   caller.
> +
> +   A suite of "helper" routines are used, allowing reuse for
> +   or1k_skip_prologue().
> +
> +   Reportedly, this is only valid for frames less than 0x7fff in size.  */
> +
> +static struct trad_frame_cache *
> +or1k_frame_cache (struct frame_info *this_frame, void **prologue_cache)
> +{
> +  struct gdbarch *gdbarch;
> +  struct trad_frame_cache *info;
> +
> +  CORE_ADDR this_pc;
> +  CORE_ADDR this_sp;
> +  CORE_ADDR this_sp_for_id;
> +  int frame_size = 0;
> +
> +  CORE_ADDR start_addr;
> +  CORE_ADDR end_addr;
> +
> +  if (frame_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog,
> +			  "or1k_frame_cache, prologue_cache = 0x%p\n",
> +			  *prologue_cache);
> +    }
> +
> +  /* Nothing to do if we already have this info.  */
> +  if (NULL != *prologue_cache)
> +    {
> +      return (struct trad_frame_cache *) *prologue_cache;
> +    }
> +
> +  /* Get a new prologue cache and populate it with default values.  */
> +  info = trad_frame_cache_zalloc (this_frame);
> +  *prologue_cache = info;
> +
> +  /* Find the start address of THIS function (which is a NORMAL frame, even if
> +     the NEXT frame is the sentinel frame) and the end of its prologue.  */
> +  this_pc = get_frame_pc (this_frame);
> +  find_pc_partial_function (this_pc, NULL, &start_addr, NULL);
> +
> +  /* Get the stack pointer if we have one (if there's no process executing yet
> +     we won't have a frame.  */
> +  this_sp = (NULL == this_frame) ? 0 :
> +    get_frame_register_unsigned (this_frame, OR1K_SP_REGNUM);
> +
> +  /* Return early if GDB couldn't find the function.  */
> +  if (start_addr == 0)
> +    {
> +      if (frame_debug)
> +	{
> +	  fprintf_unfiltered (gdb_stdlog, "  couldn't find function\n");
> +	}
> +
> +      /* JPB: 28-Apr-11. This is a temporary patch, to get round GDB crashing
> +         right at the beginning. Build the frame ID as best we can. */
> +      trad_frame_set_id (info, frame_id_build (this_sp, this_pc));
> +
> +      return info;
> +    }
> +
> +
> +  /* The default frame base of THIS frame (for ID purposes only - frame base
> +     is an overloaded term) is its stack pointer. For now we use the value of
> +     the SP register in THIS frame. However if the PC is in the prologue of
> +     THIS frame, before the SP has been set up, then the value will actually
> +     be that of the PREV frame, and we'll need to adjust it later. */
> +  trad_frame_set_this_base (info, this_sp);
> +  this_sp_for_id = this_sp;
> +
> +  /* The default is to find the PC of the PREVIOUS frame in the link register
> +     of this frame. This may be changed if we find the link register was saved
> +     on the stack. */
> +  trad_frame_set_reg_realreg (info, OR1K_NPC_REGNUM, OR1K_LR_REGNUM);
> +
> +  /* We should only examine code that is in the prologue. This is all code up
> +     to (but not including) end_addr. We should only populate the cache while
> +     the address is up to (but not including) the PC or end_addr, whichever is
> +     first. */
> +  gdbarch = get_frame_arch (this_frame);
> +  end_addr = or1k_skip_prologue (gdbarch, start_addr);
> +
> +  /* All the following analysis only occurs if we are in the prologue and have
> +     executed the code. Check we have a sane prologue size, and if zero we
> +     are frameless and can give up here. */
> +  if (end_addr < start_addr)
> +    {
> +      throw_quit ("end addr 0x%08x is less than start addr 0x%08x\n",
> +		  (unsigned int) end_addr, (unsigned int) start_addr);
> +    }
> +
> +  if (end_addr == start_addr)
> +    {
> +      frame_size = 0;
> +    }
> +  else
> +    {
> +      /* have a frame. Look for the various components */
> +      CORE_ADDR addr = start_addr;	/* Where we have got to */
> +      uint32_t inst = or1k_fetch_instruction (gdbarch, addr);
> +
> +      unsigned int ra, rb, rd;	/* For instruction analysis */
> +      int simm;
> +
> +      /* Look for the new stack pointer being set up. */
> +      if (or1k_analyse_l_addi (inst, &rd, &ra, &simm)
> +	  && (OR1K_SP_REGNUM == rd) && (OR1K_SP_REGNUM == ra)
> +	  && (simm < 0) && (0 == (simm % 4)))
> +	{
> +	  frame_size = -simm;
> +	  addr += OR1K_INSTLEN;
> +	  inst = or1k_fetch_instruction (gdbarch, addr);
> +
> +	  /* If the PC has not actually got to this point, then the frame base
> +	     will be wrong, and we adjust it.
> +
> +	     If we are past this point, then we need to populate the stack
> +	     accoringly. */
> +	  if (this_pc <= addr)
> +	    {
> +	      /* Only do if executing */
> +	      if (0 != this_sp)
> +		{
> +		  this_sp_for_id = this_sp + frame_size;
> +		  trad_frame_set_this_base (info, this_sp_for_id);
> +		}
> +	    }
> +	  else
> +	    {
> +	      /* We are past this point, so the stack pointer of the PREV
> +	         frame is frame_size greater than the stack pointer of THIS
> +	         frame. */
> +	      trad_frame_set_reg_value (info, OR1K_SP_REGNUM,
> +					this_sp + frame_size);
> +	    }
> +	}
> +
> +      /* From now on we are only populating the cache, so we stop once we get
> +         to either the end OR the current PC. */
> +      end_addr = (this_pc < end_addr) ? this_pc : end_addr;
> +
> +      /* Look for the frame pointer being manipulated. */
> +      if ((addr < end_addr)
> +	  && or1k_analyse_l_sw (inst, &simm, &ra, &rb)
> +	  && (OR1K_SP_REGNUM == ra) && (OR1K_FP_REGNUM == rb)
> +	  && (simm >= 0) && (0 == (simm % 4)))
> +	{
> +	  addr += OR1K_INSTLEN;
> +	  inst = or1k_fetch_instruction (gdbarch, addr);
> +
> +	  /* At this stage, we can find the frame pointer of the PREVIOUS
> +	     frame on the stack of the current frame. */
> +	  trad_frame_set_reg_addr (info, OR1K_FP_REGNUM, this_sp + simm);
> +
> +	  /* Look for the new frame pointer being set up */
> +	  if (addr < end_addr)
> +	    {
> +	      gdb_assert (or1k_analyse_l_addi (inst, &rd, &ra, &simm)
> +			  && (OR1K_FP_REGNUM == rd) && (OR1K_SP_REGNUM == ra)
> +			  && (simm == frame_size));
> +
> +	      addr += OR1K_INSTLEN;
> +	      inst = or1k_fetch_instruction (gdbarch, addr);
> +
> +	      /* If we have got this far, the stack pointer of the PREVIOUS
> +	         frame is the frame pointer of THIS frame. */
> +	      trad_frame_set_reg_realreg (info, OR1K_SP_REGNUM,
> +					  OR1K_FP_REGNUM);
> +	    }
> +	}
> +
> +      /* Look for the link register being saved */
> +      if ((addr < end_addr)
> +	  && or1k_analyse_l_sw (inst, &simm, &ra, &rb)
> +	  && (OR1K_SP_REGNUM == ra) && (OR1K_LR_REGNUM == rb)
> +	  && (simm >= 0) && (0 == (simm % 4)))
> +	{
> +	  addr += OR1K_INSTLEN;
> +	  inst = or1k_fetch_instruction (gdbarch, addr);
> +
> +	  /* If the link register is saved in the THIS frame, it holds the
> +	     value of the PC in the PREVIOUS frame. This overwrites the
> +	     previous information about finding the PC in the link
> +	     register.  */
> +	  trad_frame_set_reg_addr (info, OR1K_NPC_REGNUM, this_sp + simm);
> +	}
> +
> +      /* Look for arguments or callee-saved register being saved. The register
> +         must be one of the arguments (r3-r8) or the 10 callee saved registers
> +         (r10, r12, r14, r16, r18, r20, r22, r24, r26, r28, r30). The base
> +         register must be the FP (for the args) or the SP (for the
> +         callee_saved registers).  */
> +      while (addr < end_addr)
> +	{
> +	  if (or1k_analyse_l_sw (inst, &simm, &ra, &rb)
> +	      && (((OR1K_FP_REGNUM == ra) && or1k_is_arg_reg (rb))
> +		  || ((OR1K_SP_REGNUM == ra)
> +		      && or1k_is_callee_saved_reg (rb))) && (0 == (simm % 4)))
> +	    {
> +	      addr += OR1K_INSTLEN;
> +	      inst = or1k_fetch_instruction (gdbarch, addr);
> +
> +	      /* The register in the PREVIOUS frame can be found at this
> +	         location in THIS frame */
> +	      trad_frame_set_reg_addr (info, rb, this_sp + simm);
> +	    }
> +	  else
> +	    {
> +	      break;		/* Not a register save instruction */
> +	    }
> +	}
> +    }
> +
> +  /* Build the frame ID */
> +  trad_frame_set_id (info, frame_id_build (this_sp_for_id, start_addr));
> +
> +  if (frame_debug)
> +    {
> +      fprintf_unfiltered (gdb_stdlog, "  this_sp_for_id = 0x%p\n",
> +			  (void *) this_sp_for_id);
> +      fprintf_unfiltered (gdb_stdlog, "  start_addr     = 0x%p\n",
> +			  (void *) start_addr);
> +    }
> +
> +  return info;
> +
> +}
> +
> +
> +/* Implement the this_id function for the stub unwinder.  */
> +
> +static void
> +or1k_frame_this_id (struct frame_info *this_frame,
> +		    void **prologue_cache, struct frame_id *this_id)
> +{
> +  struct trad_frame_cache *info = or1k_frame_cache (this_frame,
> +						    prologue_cache);
> +
> +  trad_frame_get_id (info, this_id);
> +
> +}
> +
> +
> +/* Implement the prev_register function for the stub unwinder.  */
> +
> +static struct value *
> +or1k_frame_prev_register (struct frame_info *this_frame,
> +			  void **prologue_cache, int regnum)
> +{
> +  struct trad_frame_cache *info = or1k_frame_cache (this_frame,
> +						    prologue_cache);
> +
> +  return trad_frame_get_register (info, this_frame, regnum);
> +
> +}
> +
> +/* Data structures for the normal prologue-analysis-based
> +   unwinder.  */
> +
> +static const struct frame_unwind or1k_frame_unwind = {
> +  .type = NORMAL_FRAME,
> +  .stop_reason = default_frame_unwind_stop_reason,
> +  .this_id = or1k_frame_this_id,
> +  .prev_register = or1k_frame_prev_register,
> +  .unwind_data = NULL,
> +  .sniffer = default_frame_sniffer,
> +  .dealloc_cache = NULL,
> +  .prev_arch = NULL
> +};
> +
> +/* Architecture initialization for OpenRISC 1000.  */
> +
> +static struct gdbarch *
> +or1k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
> +{
> +  static struct frame_base or1k_frame_base;
> +  struct gdbarch *gdbarch;
> +  struct gdbarch_tdep *tdep;
> +  const struct bfd_arch_info *binfo;
> +  struct tdesc_arch_data *tdesc_data = NULL;
> +
> +  int i;
> +  int reg_index = 0;
> +  int retval;
> +  int group;
> +
> +  /* Find a candidate among the list of pre-declared architectures.  */
> +  arches = gdbarch_list_lookup_by_info (arches, &info);
> +  if (NULL != arches)
> +    {
> +      return arches->gdbarch;
> +    }
> +
> +  /* None found, create a new architecture from the information
> +     provided. Can't initialize all the target dependencies until we actually
> +     know which target we are talking to, but put in some defaults for now. */
> +
> +  binfo = info.bfd_arch_info;
> +  tdep = XNEW (struct gdbarch_tdep);

XCNEW may be better suited since it zeroes out all fields?

> +  tdep->bytes_per_word = binfo->bits_per_word / binfo->bits_per_byte;
> +  tdep->bytes_per_address = binfo->bits_per_address / binfo->bits_per_byte;
> +  gdbarch = gdbarch_alloc (&info, tdep);
> +
> +  /* Target data types.  */
> +  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_float_bit (gdbarch, 32);
> +  set_gdbarch_float_format (gdbarch, floatformats_ieee_single);
> +  set_gdbarch_double_bit (gdbarch, 64);
> +  set_gdbarch_double_format (gdbarch, floatformats_ieee_double);
> +  set_gdbarch_long_double_bit (gdbarch, 64);
> +  set_gdbarch_long_double_format (gdbarch, floatformats_ieee_double);
> +  set_gdbarch_ptr_bit (gdbarch, binfo->bits_per_address);
> +  set_gdbarch_addr_bit (gdbarch, binfo->bits_per_address);
> +  set_gdbarch_char_signed (gdbarch, 1);
> +
> +  /* Information about the target architecture */
> +  set_gdbarch_return_value (gdbarch, or1k_return_value);
> +  set_gdbarch_breakpoint_kind_from_pc (gdbarch, or1k_breakpoint::kind_from_pc);
> +  set_gdbarch_sw_breakpoint_from_kind (gdbarch, or1k_breakpoint::bp_from_kind);
> +  set_gdbarch_have_nonsteppable_watchpoint (gdbarch, 1);
> +
> +  set_gdbarch_print_insn (gdbarch, print_insn_or1k);
> +
> +  /* Register architecture */
> +  set_gdbarch_num_regs (gdbarch, OR1K_NUM_REGS);
> +  set_gdbarch_num_pseudo_regs (gdbarch, OR1K_NUM_PSEUDO_REGS);
> +  set_gdbarch_sp_regnum (gdbarch, OR1K_SP_REGNUM);
> +  set_gdbarch_pc_regnum (gdbarch, OR1K_NPC_REGNUM);
> +  set_gdbarch_ps_regnum (gdbarch, OR1K_SR_REGNUM);
> +  set_gdbarch_deprecated_fp_regnum (gdbarch, OR1K_FP_REGNUM);
> +
> +  /* Functions to supply register information */
> +  set_gdbarch_register_name (gdbarch, or1k_register_name);
> +  set_gdbarch_register_type (gdbarch, or1k_register_type);
> +  set_gdbarch_register_reggroup_p (gdbarch, or1k_register_reggroup_p);
> +
> +  /* Functions to analyse frames */
> +  set_gdbarch_skip_prologue (gdbarch, or1k_skip_prologue);
> +  set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
> +  set_gdbarch_frame_align (gdbarch, or1k_frame_align);
> +  set_gdbarch_frame_red_zone_size (gdbarch, OR1K_FRAME_RED_ZONE_SIZE);
> +
> +  /* Functions to access frame data */
> +  set_gdbarch_unwind_pc (gdbarch, or1k_unwind_pc);
> +  set_gdbarch_unwind_sp (gdbarch, or1k_unwind_sp);
> +
> +  /* Functions handling dummy frames */
> +  set_gdbarch_call_dummy_location (gdbarch, ON_STACK);
> +  set_gdbarch_push_dummy_code (gdbarch, or1k_push_dummy_code);
> +  set_gdbarch_push_dummy_call (gdbarch, or1k_push_dummy_call);
> +  set_gdbarch_dummy_id (gdbarch, or1k_dummy_id);
> +
> +  /* Frame unwinders. Use DWARF debug info if available, otherwise use our
> +     own unwinder.  */
> +  dwarf2_append_unwinders (gdbarch);
> +  frame_unwind_append_unwinder (gdbarch, &or1k_frame_unwind);
> +
> +  /* Get a CGEN CPU descriptor for this architecture.  */
> +  {
> +
> +    const char *mach_name = binfo->printable_name;
> +    enum cgen_endian endian = (info.byte_order == BFD_ENDIAN_BIG
> +			       ? CGEN_ENDIAN_BIG : CGEN_ENDIAN_LITTLE);
> +
> +    tdep->gdb_cgen_cpu_desc =
> +      or1k_cgen_cpu_open (CGEN_CPU_OPEN_BFDMACH, mach_name,
> +			  CGEN_CPU_OPEN_ENDIAN, endian, CGEN_CPU_OPEN_END);
> +
> +    or1k_cgen_init_asm (tdep->gdb_cgen_cpu_desc);
> +  }
> +
> +  /* If this mach has a delay slot.  */
> +  if (binfo->mach == bfd_mach_or1k)
> +    {
> +      set_gdbarch_single_step_through_delay
> +	(gdbarch, or1k_single_step_through_delay);
> +    }
> +
> +  /* Check any target description for validity.  */
> +  if (tdesc_has_registers (info.target_desc))
> +    {
> +      const struct tdesc_feature *feature;
> +      int valid_p;
> +
> +      feature = tdesc_find_feature (info.target_desc, "org.gnu.gdb.or1k.group0");

Where is this target description coming from? I don't see an xml file 
with the patch series. Is it going to be submitted? Or this something a 
remote stub/simulator sends GDB upon connection?

> +      if (feature == NULL)
> +        return NULL;
> +
> +      tdesc_data = tdesc_data_alloc ();
> +
> +      valid_p = 1;
> +
> +      for (i = 0; i < OR1K_NUM_REGS; i++)
> +        valid_p &= tdesc_numbered_register (feature, tdesc_data, i,
> +                                            or1k_reg_names[i]);
> +
> +      if (!valid_p)
> +        {
> +          tdesc_data_cleanup (tdesc_data);
> +          return NULL;
> +        }
> +    }
> +
> +  if (tdesc_data)
> +    {
> +      tdesc_use_registers (gdbarch, info.target_desc, tdesc_data);
> +
> +      /* Target descriptions may extend into the following groups.  */
> +      reggroup_add (gdbarch, general_reggroup);
> +      reggroup_add (gdbarch, system_reggroup);
> +      reggroup_add (gdbarch, float_reggroup);
> +      reggroup_add (gdbarch, vector_reggroup);
> +      reggroup_add (gdbarch, reggroup_new ("immu", USER_REGGROUP));
> +      reggroup_add (gdbarch, reggroup_new ("dmmu", USER_REGGROUP));
> +      reggroup_add (gdbarch, reggroup_new ("icache", USER_REGGROUP));
> +      reggroup_add (gdbarch, reggroup_new ("dcache", USER_REGGROUP));
> +      reggroup_add (gdbarch, reggroup_new ("pic", USER_REGGROUP));
> +      reggroup_add (gdbarch, reggroup_new ("timer", USER_REGGROUP));
> +      reggroup_add (gdbarch, reggroup_new ("power", USER_REGGROUP));
> +      reggroup_add (gdbarch, reggroup_new ("perf", USER_REGGROUP));
> +      reggroup_add (gdbarch, reggroup_new ("mac", USER_REGGROUP));
> +      reggroup_add (gdbarch, reggroup_new ("debug", USER_REGGROUP));
> +      reggroup_add (gdbarch, all_reggroup);
> +      reggroup_add (gdbarch, save_reggroup);
> +      reggroup_add (gdbarch, restore_reggroup);
> +    }
> +
> +  return gdbarch;
> +
> +}
> +
> +/* Dump the target specific data for this architecture.  */
> +
> +static void
> +or1k_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
> +{
> +  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +
> +  if (NULL == tdep)
> +    {
> +      return;			/* Nothing to report */
> +    }
> +
> +  fprintf_unfiltered (file, "or1k_dump_tdep: %d bytes per word\n",
> +		      tdep->bytes_per_word);
> +  fprintf_unfiltered (file, "or1k_dump_tdep: %d bytes per address\n",
> +		      tdep->bytes_per_address);
> +
> +}
> +

> +
> +extern initialize_file_ftype _initialize_or1k_tdep; /* -Wmissing-prototypes */
> +
> +void
> +_initialize_or1k_tdep (void)
> +{
> +  /* Register this architecture.  */
> +  gdbarch_register (bfd_arch_or1k, or1k_gdbarch_init, or1k_dump_tdep);
> +
> +  /* Tell remote stub that we support XML target description.  */
> +  register_remote_support_xml ("or1k");
> +}
> diff --git a/gdb/or1k-tdep.h b/gdb/or1k-tdep.h
> new file mode 100644
> index 0000000..43ae7c3
> --- /dev/null
> +++ b/gdb/or1k-tdep.h
> @@ -0,0 +1,57 @@
> +/* Definitions to target GDB to OpenRISC 1000 32-bit targets.
> +   Copyright (C) 2008-2016 Free Software Foundation, Inc.
> +   Contributed by Jeremy Bennett <jeremy.bennett@embecosm.com>
> +
> +   This file is part of GDB.
> +
> +   This program 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 of the License, or (at your option)
> +   any later version.
> +
> +   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, see <http://www.gnu.org/licenses/>.  */
> +
> +
> +#ifndef OR1K_TDEP__H
> +#define OR1K_TDEP__H
> +
> +#ifndef TARGET_OR1K
> +#define TARGET_OR1K
> +#endif
> +
> +#include "opcodes/or1k-desc.h"
> +#include "opcodes/or1k-opc.h"
> +
> +/* General Purpose Registers */
> +#define OR1K_ZERO_REGNUM          0
> +#define OR1K_SP_REGNUM            1
> +#define OR1K_FP_REGNUM            2
> +#define OR1K_FIRST_ARG_REGNUM     3
> +#define OR1K_LAST_ARG_REGNUM      8
> +#define OR1K_LR_REGNUM            9
> +#define OR1K_FIRST_SAVED_REGNUM  10
> +#define OR1K_RV_REGNUM           11
> +#define OR1K_PPC_REGNUM          (OR1K_MAX_GPR_REGS + 0)
> +#define OR1K_NPC_REGNUM          (OR1K_MAX_GPR_REGS + 1)
> +#define OR1K_SR_REGNUM           (OR1K_MAX_GPR_REGS + 2)
> +
> +/* Properties of the architecture. GDB mapping of registers is all the GPRs
> +   and SPRs followed by the PPC, NPC and SR at the end. Red zone is the area
> +   past the end of the stack reserved for exception handlers etc.  */
> +
> +#define OR1K_MAX_GPR_REGS            32
> +#define OR1K_NUM_PSEUDO_REGS         0
> +#define OR1K_NUM_REGS               (OR1K_MAX_GPR_REGS + 3)
> +#define OR1K_STACK_ALIGN             4
> +#define OR1K_INSTLEN                 4
> +#define OR1K_INSTBITLEN             (OR1K_INSTLEN * 8)
> +#define OR1K_NUM_TAP_RECORDS         8
> +#define OR1K_FRAME_RED_ZONE_SIZE     2536
> +
> +#endif /* OR1K_TDEP__H */
>

It would be nice to have all the formatting and cosmetics polished/fixed 
before we can give it another look for correctness of the code itself. 
Right now there are quite a bit of formatting issues.

Patches 2/3 and 3/3 look fine to me.



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