[PATCH 3/3] GDB: New target s12z

[John Darrington <john@darrington.wattle.id.au>]

gdb/
    * configure.tgt: Add configuration for s12z.
    * s12z-tdep.c:  New file.
    * NEWS: Mention new target.
---
 gdb/NEWS          |   4 +
 gdb/configure.tgt |   6 +
 gdb/s12z-tdep.c   | 402 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 412 insertions(+)
 create mode 100644 gdb/s12z-tdep.c

diff --git a/gdb/NEWS b/gdb/NEWS
index a7a3674375..c46056525a 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -3,6 +3,10 @@
 
 *** Changes since GDB 8.2
 
+* New targets
+
+ NXP S12Z		s12z-*-elf
+
 * GDB and GDBserver now support IPv6 connections.  IPv6 addresses
   can be passed using the '[ADDRESS]:PORT' notation, or the regular
   'ADDRESS:PORT' method.
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index 5e3bd5de71..72de1a1e4a 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -643,6 +643,12 @@ spu*-*-*)
 	build_gdbserver=yes
 	;;
 
+s12z-*-*)
+	# Target: Freescale S12z
+	gdb_target_obs="s12z-tdep.o"
+	build_gdbserver=yes
+	;;
+
 tic6x-*-*linux)
 	# Target: GNU/Linux TI C6x
 	gdb_target_obs="tic6x-tdep.o tic6x-linux-tdep.o solib-dsbt.o \
diff --git a/gdb/s12z-tdep.c b/gdb/s12z-tdep.c
new file mode 100644
index 0000000000..5169025e6b
--- /dev/null
+++ b/gdb/s12z-tdep.c
@@ -0,0 +1,402 @@
+/* Target-dependent code for the S12Z, for the GDB.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+
+   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/>.  */
+
+/* Much of this file is shamelessly copied from or1k-tdep.c and others */
+
+#include "defs.h"
+
+#include "arch-utils.h"
+#include "block.h"
+#include "cli/cli-decode.h"
+#include "common-defs.h"
+#include "dis-asm.h"
+#include "dwarf2-frame.h"
+#include "elf-bfd.h"
+#include "floatformat.h"
+#include "frame-base.h"
+#include "frame.h"
+#include "frame-unwind.h"
+#include "gdbcmd.h"
+#include "gdbcore.h"
+#include "gdbtypes.h"
+#include "infcall.h"
+#include "inferior.h"
+#include "language.h"
+#include "objfiles.h"
+#include "observable.h"
+#include "opcode/s12z.h"
+#include "osabi.h"
+#include "regcache.h"
+#include "reggroups.h"
+#include "remote.h"
+#include "symcat.h"
+#include "symfile.h"
+#include "symtab.h"
+#include "target-descriptions.h"
+#include "target.h"
+#include "trad-frame.h"
+#include "user-regs.h"
+#include "valprint.h"
+#include "value.h"
+
+
+#include <stdio.h>
+
+#define N_PHYSICAL_REGISTERS (S12Z_N_REGISTERS - 2)
+
+static const int reg_perm[N_PHYSICAL_REGISTERS] =
+  {
+   REG_D0,
+   REG_D1,
+   REG_D2,
+   REG_D3,
+   REG_D4,
+   REG_D5,
+   REG_D6,
+   REG_D7,
+   REG_X,
+   REG_Y,
+   REG_S,
+   REG_P,
+   REG_CCW
+  };
+
+static const char *
+s12z_register_name (struct gdbarch *gdbarch, int regnum)
+{
+  return registers[reg_perm[regnum]].name;
+}
+
+static CORE_ADDR
+s12z_skip_prologue (struct gdbarch *gdbarch,
+		    CORE_ADDR       pc)
+{
+  CORE_ADDR start_pc = 0;
+
+  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;
+	}
+    }
+
+  fprintf_unfiltered (gdb_stdlog, "%s:%d %s FAILED TO FIND END OF PROLOGUE PC = %08x\n", __FILE__, __LINE__,
+                      __FUNCTION__, (unsigned int) pc);
+
+  return 0;
+}
+
+static CORE_ADDR
+s12z_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
+{
+  return frame_unwind_register_unsigned (next_frame, REG_P);
+}
+
+/* Implement the unwind_sp gdbarch method.  */
+
+static CORE_ADDR
+s12z_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
+{
+  return frame_unwind_register_unsigned (next_frame, REG_S);
+}
+
+
+
+static struct type *
+s12z_register_type (struct gdbarch *gdbarch, int reg_nr)
+{
+  switch (registers[reg_perm[reg_nr]].bytes)
+    {
+    case 1:
+      return builtin_type (gdbarch)->builtin_uint8;
+    case 2:
+      return builtin_type (gdbarch)->builtin_uint16;
+    case 3:
+      return builtin_type (gdbarch)->builtin_uint24;
+    case 4:
+      return builtin_type (gdbarch)->builtin_uint32;
+    default:
+      return builtin_type (gdbarch)->builtin_uint32;
+    }
+  return builtin_type (gdbarch)->builtin_int0;
+}
+
+
+static int
+s12z_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int num)
+{
+  switch (num)
+    {
+    case 15:      return REG_S;
+    case 7:       return REG_X;
+    case 8:       return REG_Y;
+    case 42:      return REG_D0;
+    case 43:      return REG_D1;
+    case 44:      return REG_D2;
+    case 45:      return REG_D3;
+    case 46:      return REG_D4;
+    case 47:      return REG_D5;
+    case 48:      return REG_D6;
+    case 49:      return REG_D7;
+    }
+  return -1;
+}
+
+
+/* Support functions for frame handling.  */
+
+/* Initialize a prologue cache */
+
+volatile int frame_size = 0;
+
+static struct trad_frame_cache *
+s12z_frame_cache (struct frame_info *this_frame, void **prologue_cache)
+{
+  struct trad_frame_cache *info;
+
+  CORE_ADDR this_sp;
+  CORE_ADDR this_sp_for_id;
+
+  CORE_ADDR start_addr;
+  CORE_ADDR end_addr;
+
+  /* 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.  */
+  CORE_ADDR this_pc = get_frame_pc (this_frame);
+  struct gdbarch *gdbarch = get_frame_arch (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, REG_S);
+
+  /* Return early if GDB couldn't find the function.  */
+  if (start_addr == 0)
+    {
+      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, S12Z_NPC_REGNUM, S12Z_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.  */
+  end_addr = s12z_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)
+    error (_("end addr %s is less than start addr %s"),
+	   paddress (gdbarch, end_addr), paddress (gdbarch, start_addr));
+
+  if (end_addr == start_addr)
+    {
+      frame_size = 0;
+    }
+  else
+    {
+      CORE_ADDR addr = start_addr; /* Where we have got to */
+
+      gdb_byte byte;
+
+      if (0 != target_read_code (addr, &byte, 1))
+        memory_error (TARGET_XFER_E_IO, addr);
+
+      int simm;
+      if (byte == 0x1a)   /* LEA S, (S, xxxx) */
+        {
+          if (0 != target_read_code (addr + 1, &byte, 1))
+            memory_error (TARGET_XFER_E_IO, addr);
+
+          simm = (signed char) byte;
+	  frame_size = -simm;
+	  addr += 2;
+
+	  /* 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
+	     accordingly.  */
+	  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, REG_S,
+					this_sp + frame_size + 3);
+	    }
+        }
+
+      /* 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;
+
+
+      trad_frame_set_reg_addr (info, REG_P, this_sp + frame_size);
+    }
+
+  /* Build the frame ID */
+  trad_frame_set_id (info, frame_id_build (this_sp_for_id, start_addr));
+
+  return info;
+}
+
+/* Implement the this_id function for the stub unwinder.  */
+
+static void
+s12z_frame_this_id (struct frame_info *this_frame,
+		    void **prologue_cache, struct frame_id *this_id)
+{
+  struct trad_frame_cache *info = s12z_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 *
+s12z_frame_prev_register (struct frame_info *this_frame,
+			  void **prologue_cache, int regnum)
+{
+  struct trad_frame_cache *info = s12z_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 s12z_frame_unwind = {
+  NORMAL_FRAME,
+  default_frame_unwind_stop_reason,
+  s12z_frame_this_id,
+  s12z_frame_prev_register,
+  NULL,
+  default_frame_sniffer,
+  NULL,
+};
+
+
+constexpr gdb_byte s12z_break_insn[] = {0x00};
+
+typedef BP_MANIPULATION (s12z_break_insn) s12z_breakpoint;
+
+struct gdbarch_tdep
+{
+};
+
+static struct gdbarch *
+s12z_gdbarch_init (struct gdbarch_info info,
+                    struct gdbarch_list *arches)
+{
+  struct gdbarch_tdep *tdep = (struct gdbarch_tdep *) xmalloc (sizeof *tdep);
+  struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);
+
+  /* Target data types.  */
+  set_gdbarch_short_bit (gdbarch, 16);
+  set_gdbarch_int_bit (gdbarch, 16);
+  set_gdbarch_long_bit (gdbarch, 32);
+  set_gdbarch_long_long_bit (gdbarch, 32);
+  set_gdbarch_ptr_bit (gdbarch, 24);
+  set_gdbarch_addr_bit (gdbarch, 24);
+  set_gdbarch_char_signed (gdbarch, 0);
+
+  set_gdbarch_ps_regnum (gdbarch, REG_CCW);
+  set_gdbarch_pc_regnum (gdbarch, REG_P);
+  set_gdbarch_sp_regnum (gdbarch, REG_S);
+
+
+  set_gdbarch_breakpoint_kind_from_pc (gdbarch,
+				       s12z_breakpoint::kind_from_pc);
+  set_gdbarch_sw_breakpoint_from_kind (gdbarch,
+				       s12z_breakpoint::bp_from_kind);
+
+  set_gdbarch_num_regs (gdbarch, S12Z_N_REGISTERS - 2);
+  set_gdbarch_register_name (gdbarch, s12z_register_name);
+  set_gdbarch_skip_prologue (gdbarch, s12z_skip_prologue);
+  set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
+  set_gdbarch_dwarf2_reg_to_regnum (gdbarch, s12z_dwarf_reg_to_regnum);
+
+  set_gdbarch_register_type (gdbarch, s12z_register_type);
+
+  /* Functions to access frame data.  */
+  set_gdbarch_unwind_pc (gdbarch, s12z_unwind_pc);
+  set_gdbarch_unwind_sp (gdbarch, s12z_unwind_sp);
+
+  dwarf2_append_unwinders (gdbarch);
+  frame_unwind_append_unwinder (gdbarch, &s12z_frame_unwind);
+
+  return gdbarch;
+}
+
+void
+_initialize_s12z_tdep (void)
+{
+  gdbarch_register (bfd_arch_s12z, s12z_gdbarch_init, NULL);
+}
-- 
2.11.0