[RFA] Submit process record and replay third time, 3/9

teawater teawater@gmail.com
Mon Feb 2 09:05:00 GMT 2009


Hi Pedro,

According to your mail, I make a new patch. Could you please help me review it?

1.  Change all
   if (foo)
     {
       bar ();
     }
to
   if (foo)
     bar ();

2. Change some paddr_nz to host_address_to_string.
3. Change sigaction to signal like remote.c to make it not os special.
4. Remove normal_stop from record.c
5. Make all files don't have any line exceeding 80 columns.

Do you think this patch is OK?

Thanks,
Hui

On Thu, Jan 22, 2009 at 21:24, Pedro Alves <pedro@codesourcery.com> wrote:
> Hi Hui, I've just skimmed through this patch, comments below.
>
> On Thursday 08 January 2009 05:46:17, teawater wrote:
>> This patch add the process record and replay target.  This is the core
>> part of process record and replay.
>
> You still haven't addressed several past comments.  :-(
>
> 1) Nit-picky nature, but I've warned you about it several months ago, so
>   I'm escalating it.  :-)
>
>   You have several formatting things you need to clean up.
>
>  Please change instances of:
>
>    if (foo)
>      {
>        bar ();
>      }
>
>  To:
>
>    if (foo)
>      bar ();
>
>  Please make sure you don't have any line exceeding 80 columns.
>
>  Please remove redundant ()'s, like in `return (0)';
>
> 2) This bit,
>
>  +/* The real beneath function pointers.  */
>  +void (*record_beneath_to_resume) (ptid_t, int, enum target_signal);
>  +ptid_t (*record_beneath_to_wait) (ptid_t, struct target_waitstatus *);
>  +void (*record_beneath_to_store_registers) (struct regcache *, int regno);
>  +LONGEST (*record_beneath_to_xfer_partial) (struct target_ops * ops,
>  +                                          enum target_object object,
>  +                                          const char *annex,
>  +                                          gdb_byte * readbuf,
>  +                                          const gdb_byte * writebuf,
>  +                                          ULONGEST offset, LONGEST len);
>  +int (*record_beneath_to_insert_breakpoint) (struct bp_target_info *);
>  +int (*record_beneath_to_remove_breakpoint) (struct bp_target_info *);
>
> And the corresponding bit in target.c that sets these function pointers, and
> the RECORD_IS_REPLAY and TARGET_IS_PROCESS_RECORD macros, add coupling
> between the record target, and the core of gdb, that sounds unnecessary if
> we're adding record as a target stratum.  I'd really like to see those function
> pointers go away, and mentioned adding new target vector entries for the properties
> of record target you want checked in common code.  I've suggested how before, did
> you try it?
>
> 2.1) Related to coupling as well.  You've added record.c to the list of files that are
> built on all hosts, but I don't think that record.c is currently buildable on all
> hosts.  E.g., you're using sigaction unconditionally.  I didn't spot any call to
> a function defined in a *-nat.c file in this patch, but if you have any, you'll need
> to either remove/rewrite it (ideal, I expect), or build record.c on native
> linux hosts only.
>
> 3) This is a new one:  I'd prefer we don't add calls to
> normal_stop outside core inferior control code.  There's only one left in go32-nat.c,
> and that has been on my list to eliminate.
>
> --
> Pedro Alves
>
-------------- next part --------------
---
 Makefile.in |    4 
 record.c    | 1217 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 record.h    |  101 ++++
 3 files changed, 1320 insertions(+), 2 deletions(-)

--- a/Makefile.in
+++ b/Makefile.in
@@ -658,7 +658,7 @@ SFILES = ada-exp.y ada-lang.c ada-typepr
 	valarith.c valops.c valprint.c value.c varobj.c vec.c \
 	wrapper.c \
 	xml-tdesc.c xml-support.c \
-	inferior.c
+	inferior.c record.c
 
 LINTFILES = $(SFILES) $(YYFILES) $(CONFIG_SRCS) init.c
 
@@ -809,7 +809,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $
 	solib.o solib-null.o \
 	prologue-value.o memory-map.o xml-support.o \
 	target-descriptions.o target-memory.o xml-tdesc.o xml-builtin.o \
-	inferior.o osdata.o
+	inferior.o osdata.o record.o
 
 TSOBS = inflow.o
 
--- /dev/null
+++ b/record.c
@@ -0,0 +1,1217 @@
+/* Process record and replay target for GDB, the GNU debugger.
+
+   Copyright (C) 2008 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/>.  */
+
+#include "defs.h"
+#include "target.h"
+#include "gdbcmd.h"
+#include "regcache.h"
+#include "inferior.h"
+#include "gdbthread.h"
+#include "event-top.h"
+#include "annotate.h"
+#include "observer.h"
+#include "record.h"
+
+#include <signal.h>
+
+#define DEFAULT_RECORD_INSN_MAX_NUM	200000
+
+int record_debug = 0;
+
+record_t record_first;
+record_t *record_list = &record_first;
+record_t *record_arch_list_head = NULL;
+record_t *record_arch_list_tail = NULL;
+struct regcache *record_regcache = NULL;
+
+/* 1 ask user. 0 auto delete the last record_t.  */
+static int record_stop_at_limit = 1;
+static int record_insn_max_num = DEFAULT_RECORD_INSN_MAX_NUM;
+static int record_insn_num = 0;
+
+struct target_ops record_ops;
+static int record_resume_step = 0;
+static enum target_signal record_resume_siggnal;
+static int record_get_sig = 0;
+static sigset_t record_maskall;
+static int record_gdb_operation_disable = 0;
+int record_will_store_registers = 0;
+
+extern struct bp_location *bp_location_chain;
+
+/* The real beneath function pointers.  */
+void (*record_beneath_to_resume) (ptid_t, int, enum target_signal);
+ptid_t (*record_beneath_to_wait) (ptid_t, struct target_waitstatus *);
+void (*record_beneath_to_store_registers) (struct regcache *, int regno);
+LONGEST (*record_beneath_to_xfer_partial) (struct target_ops * ops,
+					   enum target_object object,
+					   const char *annex,
+					   gdb_byte * readbuf,
+					   const gdb_byte * writebuf,
+					   ULONGEST offset, LONGEST len);
+int (*record_beneath_to_insert_breakpoint) (struct bp_target_info *);
+int (*record_beneath_to_remove_breakpoint) (struct bp_target_info *);
+
+static void
+record_list_release (record_t * rec)
+{
+  record_t *tmp;
+
+  if (!rec)
+    return;
+
+  while (rec->next)
+    {
+      rec = rec->next;
+    }
+
+  while (rec->prev)
+    {
+      tmp = rec;
+      rec = rec->prev;
+      if (tmp->type == record_reg)
+	xfree (tmp->u.reg.val);
+      else if (tmp->type == record_mem)
+	xfree (tmp->u.mem.val);
+      xfree (tmp);
+    }
+
+  if (rec != &record_first)
+    xfree (rec);
+}
+
+static void
+record_list_release_next (void)
+{
+  record_t *rec = record_list;
+  record_t *tmp = rec->next;
+  rec->next = NULL;
+  while (tmp)
+    {
+      rec = tmp->next;
+      if (tmp->type == record_reg)
+	record_insn_num--;
+      else if (tmp->type == record_reg)
+	xfree (tmp->u.reg.val);
+      else if (tmp->type == record_mem)
+	xfree (tmp->u.mem.val);
+      xfree (tmp);
+      tmp = rec;
+    }
+}
+
+static void
+record_list_release_first (void)
+{
+  record_t *tmp = NULL;
+  enum record_type type;
+
+  if (!record_first.next)
+    return;
+
+  while (1)
+    {
+      type = record_first.next->type;
+
+      if (type == record_reg)
+	xfree (record_first.next->u.reg.val);
+      else if (type == record_mem)
+	xfree (record_first.next->u.mem.val);
+      tmp = record_first.next;
+      record_first.next = tmp->next;
+      xfree (tmp);
+
+      if (!record_first.next)
+	{
+	  gdb_assert (record_insn_num == 1);
+	  break;
+	}
+
+      record_first.next->prev = &record_first;
+
+      if (type == record_end)
+	break;
+    }
+
+  record_insn_num--;
+}
+
+/* Add a record_t to record_arch_list.  */
+static void
+record_arch_list_add (record_t * rec)
+{
+  if (record_debug > 1)
+    fprintf_unfiltered (gdb_stdlog,
+			"Process record: record_arch_list_add %s.\n",
+			host_address_to_string (rec));
+
+  if (record_arch_list_tail)
+    {
+      record_arch_list_tail->next = rec;
+      rec->prev = record_arch_list_tail;
+      record_arch_list_tail = rec;
+    }
+  else
+    {
+      record_arch_list_head = rec;
+      record_arch_list_tail = rec;
+    }
+}
+
+/* Record the value of a register ("num") to record_arch_list.  */
+int
+record_arch_list_add_reg (int num)
+{
+  record_t *rec;
+
+  if (record_debug > 1)
+    fprintf_unfiltered (gdb_stdlog,
+			"Process record: add register num = %d to "
+			"record list.\n",
+			num);
+
+  rec = (record_t *) xmalloc (sizeof (record_t));
+  rec->u.reg.val = (gdb_byte *) xmalloc (MAX_REGISTER_SIZE);
+  rec->prev = NULL;
+  rec->next = NULL;
+  rec->type = record_reg;
+  rec->u.reg.num = num;
+
+  regcache_raw_read (record_regcache, num, rec->u.reg.val);
+
+  record_arch_list_add (rec);
+
+  return 0;
+}
+
+/* Record the value of a region of memory whose address is "addr" and
+   length is "len" to record_arch_list.  */
+
+int
+record_arch_list_add_mem (CORE_ADDR addr, int len)
+{
+  record_t *rec;
+
+  if (record_debug > 1)
+    fprintf_unfiltered (gdb_stdlog,
+			"Process record: add mem addr = 0x%s len = %d to "
+			"record list.\n",
+			paddr_nz (addr), len);
+
+  if (!addr)
+    return 0;
+
+  rec = (record_t *) xmalloc (sizeof (record_t));
+  rec->u.mem.val = (gdb_byte *) xmalloc (len);
+  rec->prev = NULL;
+  rec->next = NULL;
+  rec->type = record_mem;
+  rec->u.mem.addr = addr;
+  rec->u.mem.len = len;
+
+  if (target_read_memory (addr, rec->u.mem.val, len))
+    {
+      if (record_debug)
+	fprintf_unfiltered (gdb_stdlog,
+			    "Process record: error reading memory at "
+			    "addr = 0x%s len = %d.\n",
+			    paddr_nz (addr), len);
+      xfree (rec->u.mem.val);
+      xfree (rec);
+      return -1;
+    }
+
+  record_arch_list_add (rec);
+
+  return 0;
+}
+
+/* Add a record_end type record_t to record_arch_list.  */
+int
+record_arch_list_add_end (int need_dasm)
+{
+  record_t *rec;
+
+  if (record_debug > 1)
+    fprintf_unfiltered (gdb_stdlog,
+			"Process record: add end need_dasm = %d to "
+			"arch list.\n",
+			need_dasm);
+
+  rec = (record_t *) xmalloc (sizeof (record_t));
+  rec->prev = NULL;
+  rec->next = NULL;
+  rec->type = record_end;
+
+  rec->u.need_dasm = need_dasm;
+
+  record_arch_list_add (rec);
+
+  return 0;
+}
+
+static void
+record_check_insn_num (int set_terminal)
+{
+  if (record_insn_max_num)
+    {
+      gdb_assert (record_insn_num <= record_insn_max_num);
+      if (record_insn_num == record_insn_max_num)
+	{
+	  /* Ask user what to do.  */
+	  if (record_stop_at_limit)
+	    {
+	      int q;
+	      if (set_terminal)
+		target_terminal_ours ();
+	      q = yquery (_("Do you want to auto delete previous execution "
+			    "log entries when record/replay buffer becomes "
+			    "full (record-stop-at-limit)?"));
+	      if (set_terminal)
+		target_terminal_inferior ();
+	      if (q)
+		record_stop_at_limit = 0;
+	      else
+		error (_("Process record: inferior program stopped."));
+	    }
+	}
+    }
+}
+
+static void
+record_normal_stop (void)
+{
+  finish_thread_state (minus_one_ptid);
+
+  if (!breakpoints_always_inserted_mode () && target_has_execution)
+    remove_breakpoints ();
+
+  target_terminal_ours ();
+
+  if (target_has_stack && !stop_stack_dummy)
+    set_current_sal_from_frame (get_current_frame (), 1);
+
+  select_frame (get_current_frame ());
+
+  annotate_stopped ();
+  if (!suppress_stop_observer)
+    {
+      if (!ptid_equal (inferior_ptid, null_ptid))
+	observer_notify_normal_stop (inferior_thread ()->stop_bpstat);
+      else
+	observer_notify_normal_stop (NULL);
+    }
+}
+
+/* Before inferior step (when GDB record the running message, inferior
+   only can step), GDB will call this function to record the values to
+   record_list.  This function will call gdbarch_process_record to
+   record the running message of inferior and set them to
+   record_arch_list, and add it to record_list.  */
+
+static void
+record_message_cleanups (void *ignore)
+{
+  record_list_release (record_arch_list_tail);
+  set_executing (inferior_ptid, 0);
+  record_normal_stop ();
+}
+
+void
+record_message (struct gdbarch *gdbarch)
+{
+  int ret;
+  struct cleanup *old_cleanups = make_cleanup (record_message_cleanups, 0);
+
+  record_arch_list_head = NULL;
+  record_arch_list_tail = NULL;
+
+  /* Check record_insn_num.  */
+  record_check_insn_num (1);
+
+  record_regcache = get_current_regcache ();
+
+  ret = gdbarch_process_record (gdbarch,
+				regcache_read_pc (record_regcache));
+  if (ret > 0)
+    error (_("Process record: inferior program stopped."));
+  if (ret < 0)
+    error (_("Process record: failed to record execution log."));
+
+  discard_cleanups (old_cleanups);
+
+  record_list->next = record_arch_list_head;
+  record_arch_list_head->prev = record_list;
+  record_list = record_arch_list_tail;
+
+  if (record_insn_num == record_insn_max_num && record_insn_max_num)
+    record_list_release_first ();
+  else
+    record_insn_num++;
+}
+
+/* Things to clean up if we error or QUIT out of function that set
+   record_gdb_operation_disable (ie. command that caused target_wait to be called).  */
+static void
+record_gdb_operation_disable_cleanups (void *ignore)
+{
+  record_gdb_operation_disable = 0;
+}
+
+struct cleanup *
+record_gdb_operation_disable_set (void)
+{
+  struct cleanup *old_cleanups = make_cleanup (record_gdb_operation_disable_cleanups, 0);
+  record_gdb_operation_disable = 1;
+
+  return old_cleanups;
+}
+
+static void
+record_open (char *name, int from_tty)
+{
+  if (record_debug)
+    fprintf_unfiltered (gdb_stdlog, "Process record: record_open\n");
+
+  /* check exec */
+  if (!target_has_execution)
+    error (_("Process record: the program is not being run."));
+  if (non_stop)
+    error (_("Process record target can't debug inferior in non-stop mode "
+	     "(non-stop)."));
+  if (target_async_permitted)
+    error (_("Process record target can't debug inferior in asynchronous "
+	     "mode (target-async)."));
+
+  if (!gdbarch_process_record_p (current_gdbarch))
+    error (_("Process record: the current architecture doesn't support "
+	     "record function."));
+
+  /* Check if record target is already running.  */
+  if (TARGET_IS_PROCESS_RECORD)
+    {
+      if (!nquery
+	  (_("Process record target already running, do you want to delete "
+	     "the old record log?")))
+	return;
+    }
+
+  push_target (&record_ops);
+
+  /* Reset */
+  record_insn_num = 0;
+  record_list = &record_first;
+  record_list->next = NULL;
+}
+
+static void
+record_close (int quitting)
+{
+  if (record_debug)
+    fprintf_unfiltered (gdb_stdlog, "Process record: record_close\n");
+
+  record_list_release (record_list);
+}
+
+static void
+record_resume (ptid_t ptid, int step, enum target_signal siggnal)
+{
+  record_resume_step = step;
+  record_resume_siggnal = siggnal;
+
+  if (!RECORD_IS_REPLAY)
+    {
+      record_message (current_gdbarch);
+      record_beneath_to_resume (ptid, 1, siggnal);
+    }
+}
+
+static void
+record_sig_handler (int signo)
+{
+  if (record_debug)
+    fprintf_unfiltered (gdb_stdlog, "Process record: get a signal\n");
+
+  record_resume_step = 1;
+  record_get_sig = 1;
+}
+
+static void
+record_wait_cleanups (void *ignore)
+{
+  if (execution_direction == EXEC_REVERSE)
+    {
+      if (record_list->next)
+	record_list = record_list->next;
+    }
+  else
+    record_list = record_list->prev;
+
+  set_executing (inferior_ptid, 0);
+  record_normal_stop ();
+}
+
+/* record_wait
+   In replay mode, this function examines the recorded log and
+   determines where to stop.  */
+
+static ptid_t
+record_wait (ptid_t ptid, struct target_waitstatus *status)
+{
+  struct cleanup *set_cleanups = record_gdb_operation_disable_set ();
+
+  if (record_debug)
+    fprintf_unfiltered (gdb_stdlog,
+			"Process record: record_wait "
+			"record_resume_step = %d\n",
+			record_resume_step);
+
+  if (!RECORD_IS_REPLAY)
+    {
+      if (record_resume_step)
+	{
+	  /* This is a single step.  */
+	  return record_beneath_to_wait (ptid, status);
+	}
+      else
+	{
+	  if (record_resume_step)
+	    {
+	      /* This is a single step.  */
+	      return record_beneath_to_wait (ptid, status);
+	    }
+	  else
+	    {
+	      /* This is not a single step.  */
+	      ptid_t ret;
+	      int is_breakpoint = 1;
+	      CORE_ADDR pc = 0;
+	      int pc_is_read = 0;
+	      struct bp_location *bl;
+	      struct breakpoint *b;
+
+	      do
+		{
+		  ret = record_beneath_to_wait (ptid, status);
+
+		  if (status->kind == TARGET_WAITKIND_STOPPED
+		      && status->value.sig == TARGET_SIGNAL_TRAP)
+		    {
+		      /* Check if there is a breakpoint.  */
+		      pc_is_read = 0;
+		      registers_changed ();
+		      for (bl = bp_location_chain; bl; bl = bl->global_next)
+			{
+			  b = bl->owner;
+			  gdb_assert (b);
+			  if (b->enable_state != bp_enabled
+			      && b->enable_state != bp_permanent)
+			    continue;
+			  if (!pc_is_read)
+			    {
+			      pc =
+				regcache_read_pc (get_thread_regcache (ret));
+			      pc_is_read = 1;
+			    }
+			  switch (b->type)
+			    {
+			    default:
+			      if (bl->address == pc)
+				goto breakpoint;
+			      break;
+
+			    case bp_watchpoint:
+			      /* XXX teawater: I still not very clear how to
+				 deal with it.  */
+			      goto breakpoint;
+			      break;
+
+			    case bp_catchpoint:
+			      gdb_assert (b->ops != NULL
+					  && b->ops->breakpoint_hit != NULL);
+			      if (b->ops->breakpoint_hit (b))
+				goto breakpoint;
+			      break;
+
+			    case bp_hardware_watchpoint:
+			    case bp_read_watchpoint:
+			    case bp_access_watchpoint:
+			      if (STOPPED_BY_WATCHPOINT (0))
+				goto breakpoint;
+			      break;
+			    }
+			}
+
+		      /* There is not a breakpoint.  */
+		      record_message (current_gdbarch);
+		      record_beneath_to_resume (ptid, 1,
+						record_resume_siggnal);
+		      continue;
+		    }
+
+		  is_breakpoint = 0;
+
+		breakpoint:
+		  /* Add gdbarch_decr_pc_after_break to pc because gdb will
+		     expect the pc to be at address plus decr_pc_after_break
+		     when the inferior stops at a breakpoint.  */
+		  if (is_breakpoint)
+		    {
+		      CORE_ADDR decr_pc_after_break =
+			gdbarch_decr_pc_after_break (current_gdbarch);
+		      if (decr_pc_after_break)
+			{
+			  if (!pc_is_read)
+			    pc =
+			      regcache_read_pc (get_thread_regcache (ret));
+			  regcache_write_pc (get_thread_regcache (ret),
+					     pc + decr_pc_after_break);
+			}
+		    }
+
+		  break;
+		}
+	      while (1);
+
+	      return ret;
+	    }
+	}
+    }
+  else
+    {
+      int need_dasm = 0;
+      struct regcache *regcache = get_current_regcache ();
+      int continue_flag = 1;
+      int first_record_end = 1;
+      struct cleanup *old_cleanups = make_cleanup (record_wait_cleanups, 0);
+      CORE_ADDR tmp_pc;
+
+      status->kind = TARGET_WAITKIND_STOPPED;
+
+      /* Check breakpoint when forward execute.  */
+      if (execution_direction == EXEC_FORWARD)
+	{
+	  tmp_pc = regcache_read_pc (regcache);
+	  if (breakpoint_inserted_here_p (tmp_pc))
+	    {
+	      if (record_debug)
+		fprintf_unfiltered (gdb_stdlog,
+				    "Process record: break at 0x%s.\n",
+				    paddr_nz (tmp_pc));
+	      if (gdbarch_decr_pc_after_break (get_regcache_arch (regcache))
+		  && !record_resume_step)
+		regcache_write_pc (regcache,
+				   tmp_pc +
+				   gdbarch_decr_pc_after_break
+				   (get_regcache_arch (regcache)));
+	      goto replay_out;
+	    }
+	}
+
+      record_get_sig = 0;
+      signal (SIGINT, record_sig_handler);
+      /* If GDB is in terminal_inferior mode, it will not get the signal.
+         And in GDB replay mode, GDB doesn't need to be in terminal_inferior
+         mode, because inferior will not executed.
+         Then set it to terminal_ours to make GDB get the signal.  */
+      target_terminal_ours ();
+
+      /* In EXEC_FORWARD mode, record_list points to the tail of prev
+         instruction.  */
+      if (execution_direction == EXEC_FORWARD && record_list->next)
+	record_list = record_list->next;
+
+      /* Loop over the record_list, looking for the next place to
+	 stop.  */
+      do
+	{
+	  /* Check for beginning and end of log.  */
+	  if (execution_direction == EXEC_REVERSE
+	      && record_list == &record_first)
+	    {
+	      /* Hit beginning of record log in reverse.  */
+	      status->kind = TARGET_WAITKIND_NO_HISTORY;
+	      break;
+	    }
+	  if (execution_direction != EXEC_REVERSE && !record_list->next)
+	    {
+	      /* Hit end of record log going forward.  */
+	      status->kind = TARGET_WAITKIND_NO_HISTORY;
+	      break;
+	    }
+
+	  /* Set ptid, register and memory according to record_list.  */
+	  if (record_list->type == record_reg)
+	    {
+	      /* reg */
+	      gdb_byte reg[MAX_REGISTER_SIZE];
+	      if (record_debug > 1)
+		fprintf_unfiltered (gdb_stdlog,
+				    "Process record: record_reg %s to "
+				    "inferior num = %d.\n",
+				    host_address_to_string (record_list),
+				    record_list->u.reg.num);
+	      regcache_cooked_read (regcache, record_list->u.reg.num, reg);
+	      regcache_cooked_write (regcache, record_list->u.reg.num,
+				     record_list->u.reg.val);
+	      memcpy (record_list->u.reg.val, reg, MAX_REGISTER_SIZE);
+	    }
+	  else if (record_list->type == record_mem)
+	    {
+	      /* mem */
+	      gdb_byte *mem = alloca (record_list->u.mem.len);
+	      if (record_debug > 1)
+		fprintf_unfiltered (gdb_stdlog,
+				    "Process record: record_mem %s to "
+				    "inferior addr = 0x%s len = %d.\n",
+				    host_address_to_string (record_list),
+				    paddr_nz (record_list->u.mem.addr),
+				    record_list->u.mem.len);
+
+	      if (target_read_memory
+		  (record_list->u.mem.addr, mem, record_list->u.mem.len))
+		error (_("Process record: error reading memory at "
+			 "addr = 0x%s len = %d."),
+		       paddr_nz (record_list->u.mem.addr),
+		       record_list->u.mem.len);
+
+	      if (target_write_memory
+		  (record_list->u.mem.addr, record_list->u.mem.val,
+		   record_list->u.mem.len))
+		error (_
+		       ("Process record: error writing memory at "
+			"addr = 0x%s len = %d."),
+		       paddr_nz (record_list->u.mem.addr),
+		       record_list->u.mem.len);
+
+	      memcpy (record_list->u.mem.val, mem, record_list->u.mem.len);
+	    }
+	  else
+	    {
+	      if (record_debug > 1)
+		fprintf_unfiltered (gdb_stdlog,
+				    "Process record: record_end %s to "
+				    "inferior need_dasm = %d.\n",
+				    host_address_to_string (record_list),
+				    record_list->u.need_dasm);
+
+	      if (execution_direction == EXEC_FORWARD)
+		need_dasm = record_list->u.need_dasm;
+	      if (need_dasm)
+		gdbarch_process_record_dasm (current_gdbarch);
+
+	      if (first_record_end && execution_direction == EXEC_REVERSE)
+		{
+		  /* When reverse excute, the first record_end is the part of
+		     current instruction.  */
+		  first_record_end = 0;
+		}
+	      else
+		{
+		  /* In EXEC_REVERSE mode, this is the record_end of prev
+		     instruction.
+		     In EXEC_FORWARD mode, this is the record_end of current
+		     instruction.  */
+		  /* step */
+		  if (record_resume_step)
+		    {
+		      if (record_debug > 1)
+			fprintf_unfiltered (gdb_stdlog,
+					    "Process record: step.\n");
+		      continue_flag = 0;
+		    }
+
+		  /* check breakpoint */
+		  tmp_pc = regcache_read_pc (regcache);
+		  if (breakpoint_inserted_here_p (tmp_pc))
+		    {
+		      if (record_debug)
+			fprintf_unfiltered (gdb_stdlog,
+					    "Process record: break "
+					    "at 0x%s.\n",
+					    paddr_nz (tmp_pc));
+		      if (gdbarch_decr_pc_after_break (get_regcache_arch (regcache))
+			  && execution_direction == EXEC_FORWARD
+			  && !record_resume_step)
+			regcache_write_pc (regcache,
+					   tmp_pc +
+					   gdbarch_decr_pc_after_break
+					   (get_regcache_arch (regcache)));
+		      continue_flag = 0;
+		    }
+		}
+	      if (execution_direction == EXEC_REVERSE)
+		need_dasm = record_list->u.need_dasm;
+	    }
+
+next:
+	  if (continue_flag)
+	    {
+	      if (execution_direction == EXEC_REVERSE)
+		{
+		  if (record_list->prev)
+		    record_list = record_list->prev;
+		}
+	      else
+		{
+		  if (record_list->next)
+		    record_list = record_list->next;
+		}
+	    }
+	}
+      while (continue_flag);
+
+      signal (SIGINT, handle_sigint);
+
+replay_out:
+      if (record_get_sig)
+	status->value.sig = TARGET_SIGNAL_INT;
+      else
+	status->value.sig = TARGET_SIGNAL_TRAP;
+
+      discard_cleanups (old_cleanups);
+    }
+
+  do_cleanups (set_cleanups);
+  return inferior_ptid;
+}
+
+static void
+record_disconnect (struct target_ops *target, char *args, int from_tty)
+{
+  if (record_debug)
+    fprintf_unfiltered (gdb_stdlog, "Process record: record_disconnect\n");
+
+  unpush_target (&record_ops);
+  target_disconnect (args, from_tty);
+}
+
+static void
+record_detach (struct target_ops *ops, char *args, int from_tty)
+{
+  if (record_debug)
+    fprintf_unfiltered (gdb_stdlog, "Process record: record_detach\n");
+
+  unpush_target (&record_ops);
+  target_detach (args, from_tty);
+}
+
+static void
+record_mourn_inferior (struct target_ops *ops)
+{
+  if (record_debug)
+    fprintf_unfiltered (gdb_stdlog, "Process record: "
+			            "record_mourn_inferior\n");
+
+  unpush_target (&record_ops);
+  target_mourn_inferior ();
+}
+
+/* Close process record target before killing the inferior process.  */
+static void
+record_kill (void)
+{
+  if (record_debug)
+    fprintf_unfiltered (gdb_stdlog, "Process record: record_kill\n");
+
+  unpush_target (&record_ops);
+  target_kill ();
+}
+
+/* Record registers change (by user or by GDB) to list as an instruction.  */
+static void
+record_registers_change (struct regcache *regcache, int regnum)
+{
+  /* Check record_insn_num.  */
+  record_check_insn_num (0);
+
+  record_arch_list_head = NULL;
+  record_arch_list_tail = NULL;
+
+  record_regcache = get_current_regcache ();
+
+  if (regnum < 0)
+    {
+      int i;
+      for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++)
+	{
+	  if (record_arch_list_add_reg (i))
+	    {
+	      record_list_release (record_arch_list_tail);
+	      error (_("Process record: failed to record execution log."));
+	    }
+	}
+    }
+  else
+    {
+      if (record_arch_list_add_reg (regnum))
+	{
+	  record_list_release (record_arch_list_tail);
+	  error (_("Process record: failed to record execution log."));
+	}
+    }
+  if (record_arch_list_add_end (0))
+    {
+      record_list_release (record_arch_list_tail);
+      error (_("Process record: failed to record execution log."));
+    }
+  record_list->next = record_arch_list_head;
+  record_arch_list_head->prev = record_list;
+  record_list = record_arch_list_tail;
+
+  if (record_insn_num == record_insn_max_num && record_insn_max_num)
+    record_list_release_first ();
+  else
+    record_insn_num++;
+}
+
+static void
+record_store_registers (struct regcache *regcache, int regno)
+{
+  if (!record_gdb_operation_disable)
+    {
+      if (RECORD_IS_REPLAY)
+	{
+	  int n;
+	  struct cleanup *old_cleanups;
+
+	  /* Let user choose if he wants to write register or not.  */
+	  if (regno < 0)
+	    n =
+	      nquery (_("Because GDB is in replay mode, changing the "
+			"value of a register will make the execution "
+			"log unusable from this point onward.  "
+			"Change all registers?"));
+	  else
+	    n =
+	      nquery (_("Because GDB is in replay mode, changing the value "
+			"of a register will make the execution log unusable "
+			"from this point onward.  Change register %s?"),
+		      gdbarch_register_name (get_regcache_arch (regcache),
+					       regno));
+
+	  if (!n)
+	    {
+	      /* Invalidate the value of regcache that was set in function
+	         "regcache_raw_write".  */
+	      if (regno < 0)
+		{
+		  int i;
+		  for (i = 0;
+		       i < gdbarch_num_regs (get_regcache_arch (regcache));
+		       i++)
+		    regcache_invalidate (regcache, i);
+		}
+	      else
+		regcache_invalidate (regcache, regno);
+
+	      error (_("Process record canceled the operation."));
+	    }
+
+	  /* Destroy the record from here forward.  */
+	  record_list_release_next ();
+	}
+
+      record_registers_change (regcache, regno);
+    }
+  record_beneath_to_store_registers (regcache, regno);
+}
+
+/* record_xfer_partial -- behavior is conditional on RECORD_IS_REPLAY.
+   In replay mode, we cannot write memory unles we are willing to
+   invalidate the record/replay log from this point forward.  */
+
+static LONGEST
+record_xfer_partial (struct target_ops *ops, enum target_object object,
+		     const char *annex, gdb_byte * readbuf,
+		     const gdb_byte * writebuf, ULONGEST offset, LONGEST len)
+{
+  if (!record_gdb_operation_disable
+      && (object == TARGET_OBJECT_MEMORY
+	  || object == TARGET_OBJECT_RAW_MEMORY) && writebuf)
+    {
+      if (RECORD_IS_REPLAY)
+	{
+	  /* Let user choose if he wants to write memory or not.  */
+	  if (!nquery (_("Because GDB is in replay mode, writing to memory "
+		         "will make the execution log unusable from this "
+		         "point onward.  Write memory at address 0x%s?"),
+		       paddr_nz (offset)))
+	    return -1;
+
+	  /* Destroy the record from here forward.  */
+	  record_list_release_next ();
+	}
+
+      /* Check record_insn_num */
+      record_check_insn_num (0);
+
+      /* Record registers change to list as an instruction.  */
+      record_arch_list_head = NULL;
+      record_arch_list_tail = NULL;
+      if (record_arch_list_add_mem (offset, len))
+	{
+	  record_list_release (record_arch_list_tail);
+	  if (record_debug)
+	    fprintf_unfiltered (gdb_stdlog,
+				_("Process record: failed to record "
+				  "execution log."));
+	  return -1;
+	}
+      if (record_arch_list_add_end (0))
+	{
+	  record_list_release (record_arch_list_tail);
+	  if (record_debug)
+	    fprintf_unfiltered (gdb_stdlog,
+				_("Process record: failed to record "
+				  "execution log."));
+	  return -1;
+	}
+      record_list->next = record_arch_list_head;
+      record_arch_list_head->prev = record_list;
+      record_list = record_arch_list_tail;
+
+      if (record_insn_num == record_insn_max_num && record_insn_max_num)
+	record_list_release_first ();
+      else
+	record_insn_num++;
+    }
+
+  return record_beneath_to_xfer_partial (ops, object, annex, readbuf,
+					 writebuf, offset, len);
+}
+
+/* record_insert_breakpoint
+   record_remove_breakpoint
+   Behavior is conditional on RECORD_IS_REPLAY.
+   We will not actually insert or remove breakpoints when replaying,
+   nor when recording.  */
+
+static int
+record_insert_breakpoint (struct bp_target_info *bp_tgt)
+{
+  if (!RECORD_IS_REPLAY)
+    {
+      struct cleanup *old_cleanups = record_gdb_operation_disable_set ();
+      int ret = record_beneath_to_insert_breakpoint (bp_tgt);
+
+      do_cleanups (old_cleanups);
+
+      return ret;
+    }
+
+  return 0;
+}
+
+static int
+record_remove_breakpoint (struct bp_target_info *bp_tgt)
+{
+  if (!RECORD_IS_REPLAY)
+    {
+      struct cleanup *old_cleanups = record_gdb_operation_disable_set ();
+      int ret = record_beneath_to_remove_breakpoint (bp_tgt);
+
+      do_cleanups (old_cleanups);
+
+      return ret;
+    }
+
+  return 0;
+}
+
+static int
+record_can_execute_reverse (void)
+{
+  return 1;
+}
+
+static void
+init_record_ops (void)
+{
+  record_ops.to_shortname = "record";
+  record_ops.to_longname = "Process record and replay target";
+  record_ops.to_doc =
+    "Log program while executing and replay execution from log.";
+  record_ops.to_open = record_open;
+  record_ops.to_close = record_close;
+  record_ops.to_resume = record_resume;
+  record_ops.to_wait = record_wait;
+  record_ops.to_disconnect = record_disconnect;
+  record_ops.to_detach = record_detach;
+  record_ops.to_mourn_inferior = record_mourn_inferior;
+  record_ops.to_kill = record_kill;
+  record_ops.to_create_inferior = find_default_create_inferior;
+  record_ops.to_store_registers = record_store_registers;
+  record_ops.to_xfer_partial = record_xfer_partial;
+  record_ops.to_insert_breakpoint = record_insert_breakpoint;
+  record_ops.to_remove_breakpoint = record_remove_breakpoint;
+  record_ops.to_can_execute_reverse = record_can_execute_reverse;
+  record_ops.to_stratum = record_stratum;
+  record_ops.to_magic = OPS_MAGIC;
+}
+
+static void
+show_record_debug (struct ui_file *file, int from_tty,
+		   struct cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("Debugging of process record target is %s.\n"),
+		    value);
+}
+
+/* cmd_record_start -- alias for "target record".  */
+
+static void
+cmd_record_start (char *args, int from_tty)
+{
+  execute_command ("target record", from_tty);
+}
+
+/* cmd_record_delete -- truncate the record log from the present point
+   of replay until the end.  */
+
+static void
+cmd_record_delete (char *args, int from_tty)
+{
+  if (TARGET_IS_PROCESS_RECORD)
+    {
+      if (RECORD_IS_REPLAY)
+	{
+	  if (!from_tty || query (_("Delete the log from this point forward "
+		                    "and begin to record the running message "
+		                    "at current PC?")))
+	    record_list_release_next ();
+	}
+      else
+	  printf_unfiltered (_("Already at end of record list.\n"));
+
+    }
+  else
+    printf_unfiltered (_("Process record is not started.\n"));
+}
+
+/* cmd_record_stop -- implement the "stoprecord" command.  */
+
+static void
+cmd_record_stop (char *args, int from_tty)
+{
+  if (TARGET_IS_PROCESS_RECORD)
+    {
+      if (!record_list || !from_tty || query (_("Delete recorded log and "
+	                                        "stop recording?")))
+	unpush_target (&record_ops);
+    }
+  else
+    printf_unfiltered (_("Process record is not started.\n"));
+}
+
+/* set_record_insn_max_num -- set upper limit of record log size.  */
+
+static void
+set_record_insn_max_num (char *args, int from_tty, struct cmd_list_element *c)
+{
+  if (record_insn_num > record_insn_max_num && record_insn_max_num)
+    {
+      printf_unfiltered (_("Record instructions number is bigger than "
+		           "record instructions max number.  Auto delete "
+		           "the first ones?\n"));
+
+      while (record_insn_num > record_insn_max_num)
+	record_list_release_first ();
+    }
+}
+
+/* show_record_insn_number -- print the current index
+   into the record log (number of insns recorded so far).  */
+
+static void
+show_record_insn_number (char *ignore, int from_tty)
+{
+  printf_unfiltered (_("Record instruction number is %d.\n"),
+		     record_insn_num);
+}
+
+void
+_initialize_record (void)
+{
+  /* Init record_maskall.  */
+  if (sigfillset (&record_maskall) == -1)
+    perror_with_name (_("Process record: sigfillset failed"));
+
+  /* Init record_first.  */
+  record_first.prev = NULL;
+  record_first.next = NULL;
+  record_first.type = record_end;
+  record_first.u.need_dasm = 0;
+
+  init_record_ops ();
+  add_target (&record_ops);
+
+  add_setshow_zinteger_cmd ("record", no_class, &record_debug,
+			    _("Set debugging of record/replay feature."),
+			    _("Show debugging of record/replay feature."),
+			    _("When enabled, debugging output for "
+			      "record/replay feature is displayed."),
+			    NULL, show_record_debug, &setdebuglist,
+			    &showdebuglist);
+
+  add_com ("record", class_obscure, cmd_record_start,
+	   _("Abbreviated form of \"target record\" command."));
+
+  add_com_alias ("rec", "record", class_obscure, 1);
+
+  /* XXX: I try to use some simple commands such as "disconnect" and
+     "detach" to support this functions.  But these commands all have
+     other affect to GDB such as call function "no_shared_libraries".
+     So I add special commands to GDB.  */
+  add_com ("delrecord", class_obscure, cmd_record_delete,
+	   _("Delete the rest of execution log and start recording it anew."));
+  add_com_alias ("dr", "delrecord", class_obscure, 1);
+  add_com ("stoprecord", class_obscure, cmd_record_stop,
+	   _("Stop the record/replay target."));
+  add_com_alias ("sr", "stoprecord", class_obscure, 1);
+
+  /* Record instructions number limit command.  */
+  add_setshow_boolean_cmd ("record-stop-at-limit", no_class,
+			    &record_stop_at_limit,
+			    _("Set whether record/replay stop when "
+			      "record/replay buffer becomes full."),
+			    _("Show whether record/replay stop when "
+			      "record/replay buffer becomes full."),
+	                    _("Enable is default value.\n"
+	                      "When enabled, if the record/replay buffer "
+			      "becomes full,\n"
+                              "ask user what to do.\n"
+                              "When disabled, if the record/replay buffer "
+			      "becomes full,\n"
+                              "delete it and start new recording."),
+			    NULL, NULL, &setlist, &showlist);
+  add_setshow_zinteger_cmd ("record-insn-number-max", no_class,
+			    &record_insn_max_num,
+			    _("Set record/replay buffer limit."),
+			    _("Show record/replay buffer limit."),
+			    _("Set the maximum number of instructions to be "
+                              "stored in the\n"
+                              "record/replay buffer.  "
+                              "Zero means unlimited (default 200000)."),
+			    set_record_insn_max_num,
+			    NULL, &setlist, &showlist);
+  add_info ("record-insn-number", show_record_insn_number,
+	    _("Show the current number of instructions in the "
+	      "record/replay buffer."));
+}
--- /dev/null
+++ b/record.h
@@ -0,0 +1,101 @@
+/* Process record and replay target for GDB, the GNU debugger.
+
+   Copyright (C) 2008 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/>.  */
+
+#ifndef _RECORD_H_
+#define _RECORD_H_
+
+#define TARGET_IS_PROCESS_RECORD   \
+     (current_target.beneath == &record_ops)
+#define RECORD_IS_REPLAY \
+     (record_list->next || execution_direction == EXEC_REVERSE)
+
+typedef struct record_reg_s
+{
+  int num;
+  gdb_byte *val;
+} record_reg_t;
+
+typedef struct record_mem_s
+{
+  CORE_ADDR addr;
+  int len;
+  gdb_byte *val;
+} record_mem_t;
+
+enum record_type
+{
+  record_end = 0,
+  record_reg,
+  record_mem
+};
+
+/* This is the core struct of record function.
+
+   An entity of record_t is a record of the value change of a register
+   ("record_reg") or a part of memory ("record_mem").  And each
+   instruction must has a record_t ("record_end") that points out this
+   is the last record_t of this instruction.
+
+   Each record_t is linked to "record_list" by "prev" and "next".
+ */
+typedef struct record_s
+{
+  struct record_s *prev;
+  struct record_s *next;
+  enum record_type type;
+  union
+  {
+    /* reg */
+    record_reg_t reg;
+    /* mem */
+    record_mem_t mem;
+    /* end */
+    int need_dasm;
+  } u;
+} record_t;
+
+extern int record_debug;
+extern record_t *record_list;
+extern record_t *record_arch_list_head;
+extern record_t *record_arch_list_tail;
+extern struct regcache *record_regcache;
+
+extern struct target_ops record_ops;
+
+extern int record_arch_list_add_reg (int num);
+extern int record_arch_list_add_mem (CORE_ADDR addr, int len);
+extern int record_arch_list_add_end (int need_dasm);
+extern void record_message (struct gdbarch *gdbarch);
+extern struct cleanup * record_gdb_operation_disable_set (void);
+
+extern void (*record_beneath_to_resume) (ptid_t, int, enum target_signal);
+extern ptid_t (*record_beneath_to_wait) (ptid_t, struct target_waitstatus *);
+extern void (*record_beneath_to_store_registers) (struct regcache *,
+						  int regno);
+extern LONGEST (*record_beneath_to_xfer_partial) (struct target_ops * ops,
+						  enum target_object object,
+						  const char *annex,
+						  gdb_byte * readbuf,
+						  const gdb_byte * writebuf,
+						  ULONGEST offset,
+						  LONGEST len);
+extern int (*record_beneath_to_insert_breakpoint) (struct bp_target_info *);
+extern int (*record_beneath_to_remove_breakpoint) (struct bp_target_info *);
+
+#endif /* _RECORD_H_ */


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