Index: gdb-7.5/gdb/aix64-thread.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ ./gdb/aix64-thread.c	2013-07-03 14:42:37.000000000 +0600
@@ -0,0 +1,1854 @@
+/* Low level interface for debugging AIX 4.3+ pthreads.
+
+   Copyright (C) 1999-2000, 2002, 2007-2012 Free Software Foundation,
+   Inc.
+   Written by Nick Duffek <nsd@redhat.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/>.  */
+
+
+/* This module uses the libpthdebug.a library provided by AIX 4.3+ for
+   debugging pthread applications.
+
+   Some name prefix conventions:
+     pthdb_     provided by libpthdebug.a
+     pdc_       callbacks that this module provides to libpthdebug.a
+     pd_        variables or functions interfacing with libpthdebug.a
+
+   libpthdebug peculiarities:
+
+     - pthdb_ptid_pthread() is prototyped in <sys/pthdebug.h>, but
+       it's not documented, and after several calls it stops working
+       and causes other libpthdebug functions to fail.
+
+     - pthdb_tid_pthread() doesn't always work after
+       pthdb_session_update(), but it does work after cycling through
+       all threads using pthdb_pthread().
+
+     */
+
+#include "defs.h"
+#include "gdb_assert.h"
+#include "gdbthread.h"
+#include "target.h"
+#include "inferior.h"
+#include "regcache.h"
+#include "gdbcmd.h"
+#include "ppc-tdep.h"
+#include "gdb_string.h"
+#include "observer.h"
+
+#include <procinfo.h>
+#include <sys/types.h>
+#include <sys/ptrace.h>
+#include <sys/reg.h>
+#include <sched.h>
+#include <sys/pthdebug.h>
+
+#if !HAVE_DECL_GETTHRDS
+extern int getthrds (pid_t, struct thrdsinfo64 *, int, pthdb_tid_t *, int);
+#endif
+
+/* Whether to emit debugging output.  */
+static int debug_aix_thread;
+
+/* In AIX 5.1, functions use pthdb_tid_t instead of tid_t.  */
+#ifndef PTHDB_VERSION_3
+#define pthdb_tid_t     tid_t
+#endif
+
+/* Return whether to treat PID as a debuggable thread id.  */
+
+#define PD_TID(ptid)    (pd_active && ptid_get_tid (ptid) != 0)
+
+/* Build a thread ptid.  */
+#define BUILD_THREAD(TID, PID) ptid_build (PID, 0, TID)
+
+/* Build and lwp ptid.  */
+#define BUILD_LWP(LWP, PID) MERGEPID (PID, LWP)
+
+/* pthdb_user_t value that we pass to pthdb functions.  0 causes
+   PTHDB_BAD_USER errors, so use 1.  */
+
+#define PD_USER 1
+
+/* Success and failure values returned by pthdb callbacks.  */
+
+#define PDC_SUCCESS     PTHDB_SUCCESS
+#define PDC_FAILURE     PTHDB_CALLBACK
+
+/* Private data attached to each element in GDB's thread list.  */
+
+struct private_thread_info {
+  pthdb_pthread_t pdtid;         /* thread's libpthdebug id */
+  pthdb_tid_t tid;                      /* kernel thread id */
+};
+
+/* Information about a thread of which libpthdebug is aware.  */
+
+struct pd_thread {
+  pthdb_pthread_t pdtid;
+  pthread_t pthid;
+  pthdb_tid_t tid;
+};
+
+/* This module's target-specific operations, active while pd_able is true.  */
+
+static struct target_ops aix_thread_ops;
+
+/* Address of the function that libpthread will call when libpthdebug
+   is ready to be initialized.  */
+
+static CORE_ADDR pd_brk_addr;
+
+/* Whether the current application is debuggable by pthdb.  */
+
+static int pd_able = 0;
+
+/* Whether a threaded application is being debugged.  */
+
+static int pd_active = 0;
+
+/* Whether the current architecture is 64-bit.
+   Only valid when pd_able is true.  */
+
+static int arch64;
+
+/* Forward declarations for pthdb callbacks.  */
+
+static int pdc_symbol_addrs (pthdb_user_t, pthdb_symbol_t *, int);
+static int pdc_read_data (pthdb_user_t, void *, pthdb_addr_t, size_t);
+static int pdc_write_data (pthdb_user_t, void *, pthdb_addr_t, size_t);
+static int pdc_read_regs (pthdb_user_t user, pthdb_tid_t tid,
+                          unsigned long long flags,
+                          pthdb_context_t *context);
+static int pdc_write_regs (pthdb_user_t user, pthdb_tid_t tid,
+                           unsigned long long flags,
+                           pthdb_context_t *context);
+static int pdc_alloc (pthdb_user_t, size_t, void **);
+static int pdc_realloc (pthdb_user_t, void *, size_t, void **);
+static int pdc_dealloc (pthdb_user_t, void *);
+
+/* pthdb callbacks.  */
+
+static pthdb_callbacks_t pd_callbacks = {
+  pdc_symbol_addrs,
+  pdc_read_data,
+  pdc_write_data,
+  pdc_read_regs,
+  pdc_write_regs,
+  pdc_alloc,
+  pdc_realloc,
+  pdc_dealloc,
+  NULL
+};
+
+/* Current pthdb session.  */
+
+static pthdb_session_t pd_session;
+
+/* Return a printable representation of pthdebug function return
+   STATUS.  */
+
+static char *
+pd_status2str (int status)
+{
+  switch (status)
+    {
+    case PTHDB_SUCCESS:         return "SUCCESS";
+    case PTHDB_NOSYS:           return "NOSYS";
+    case PTHDB_NOTSUP:          return "NOTSUP";
+    case PTHDB_BAD_VERSION:     return "BAD_VERSION";
+    case PTHDB_BAD_USER:        return "BAD_USER";
+    case PTHDB_BAD_SESSION:     return "BAD_SESSION";
+    case PTHDB_BAD_MODE:        return "BAD_MODE";
+    case PTHDB_BAD_FLAGS:       return "BAD_FLAGS";
+    case PTHDB_BAD_CALLBACK:    return "BAD_CALLBACK";
+    case PTHDB_BAD_POINTER:     return "BAD_POINTER";
+    case PTHDB_BAD_CMD:         return "BAD_CMD";
+    case PTHDB_BAD_PTHREAD:     return "BAD_PTHREAD";
+    case PTHDB_BAD_ATTR:        return "BAD_ATTR";
+    case PTHDB_BAD_MUTEX:       return "BAD_MUTEX";
+    case PTHDB_BAD_MUTEXATTR:   return "BAD_MUTEXATTR";
+    case PTHDB_BAD_COND:        return "BAD_COND";
+    case PTHDB_BAD_CONDATTR:    return "BAD_CONDATTR";
+    case PTHDB_BAD_RWLOCK:      return "BAD_RWLOCK";
+    case PTHDB_BAD_RWLOCKATTR:  return "BAD_RWLOCKATTR";
+    case PTHDB_BAD_KEY:         return "BAD_KEY";
+    case PTHDB_BAD_PTID:        return "BAD_PTID";
+    case PTHDB_BAD_TID:         return "BAD_TID";
+    case PTHDB_CALLBACK:        return "CALLBACK";
+    case PTHDB_CONTEXT:         return "CONTEXT";
+    case PTHDB_HELD:            return "HELD";
+    case PTHDB_NOT_HELD:        return "NOT_HELD";
+    case PTHDB_MEMORY:          return "MEMORY";
+    case PTHDB_NOT_PTHREADED:   return "NOT_PTHREADED";
+    case PTHDB_SYMBOL:          return "SYMBOL";
+    case PTHDB_NOT_AVAIL:       return "NOT_AVAIL";
+    case PTHDB_INTERNAL:        return "INTERNAL";
+    default:                    return "UNKNOWN";
+    }
+}
+
+/* A call to ptrace(REQ, ID, ...) just returned RET.  Check for
+   exceptional conditions and either return nonlocally or else return
+   1 for success and 0 for failure.  */
+
+static int
+ptrace_check (int req, int id, int ret)
+{
+  if (ret == 0 && !errno)
+    return 1;
+
+  /* According to ptrace(2), ptrace may fail with EPERM if "the
+     Identifier parameter corresponds to a kernel thread which is
+     stopped in kernel mode and whose computational state cannot be
+     read or written."  This happens quite often with register reads.  */
+
+  switch (req)
+    {
+    case PTT_READ_GPRS:
+    case PTT_READ_FPRS:
+    case PTT_READ_SPRS:
+      if (ret == -1 && errno == EPERM)
+        {
+          if (debug_aix_thread)
+            fprintf_unfiltered (gdb_stdlog,
+                                "ptrace (%d, %d) = %d (errno = %d)\n",
+                                req, id, ret, errno);
+          return ret == -1 ? 0 : 1;
+        }
+      break;
+    }
+  error (_("aix-thread: ptrace (%d, %d) returned %d (errno = %d %s)"),
+         req, id, ret, errno, safe_strerror (errno));
+  return 0;  /* Not reached.  */
+}
+
+/* Call ptracex (REQ, ID, ADDR, DATA, BUF).  Return success.  */
+
+static int
+ptrace64aix (int req, long long id, long long addr, int data, int *buf)
+{
+  errno = 0;
+  return ptrace_check (req, id, ptrace64 (req, id, addr, data, buf));
+}
+
+/* Call ptrace (REQ, ID, ADDR, DATA, BUF).  Return success.  */
+
+static int
+ptrace32 (int req, long long id, long long addr, int data, int *buf)
+{
+  errno = 0;
+  return ptrace_check (req, id,
+                       ptrace64 (req, id, (int *) addr, data, buf));
+}
+
+/* If *PIDP is a composite process/thread id, convert it to a
+   process id.  */
+
+static void
+pid_to_prc (ptid_t *ptidp)
+{
+  ptid_t ptid;
+
+  ptid = *ptidp;
+  if (PD_TID (ptid))
+    *ptidp = pid_to_ptid (PIDGET (ptid));
+}
+
+/* pthdb callback: for <i> from 0 to COUNT, set SYMBOLS[<i>].addr to
+   the address of SYMBOLS[<i>].name.  */
+
+static int
+pdc_symbol_addrs (pthdb_user_t user, pthdb_symbol_t *symbols, int count)
+{
+  struct minimal_symbol *ms;
+  int i;
+  char *name;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+      "pdc_symbol_addrs (user = %ld, symbols = 0x%lx, count = %d)\n",
+      user, (long) symbols, count);
+
+  for (i = 0; i < count; i++)
+    {
+      name = symbols[i].name;
+      if (debug_aix_thread)
+        fprintf_unfiltered (gdb_stdlog,
+                            "  symbols[%d].name = \"%s\"\n", i, name);
+
+      if (!*name)
+        symbols[i].addr = 0;
+      else
+        {
+          if (!(ms = lookup_minimal_symbol (name, NULL, NULL)))
+            {
+              if (debug_aix_thread)
+                fprintf_unfiltered (gdb_stdlog, " returning PDC_FAILURE\n");
+              return PDC_FAILURE;
+            }
+          symbols[i].addr = SYMBOL_VALUE_ADDRESS (ms);
+        }
+      if (debug_aix_thread)
+        fprintf_unfiltered (gdb_stdlog, "  symbols[%d].addr = %s\n",
+                            i, hex_string (symbols[i].addr));
+    }
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog, " returning PDC_SUCCESS\n");
+  return PDC_SUCCESS;
+}
+
+/* Read registers call back function should be able to read the
+   context information of a debuggee kernel thread from an active
+   process or from a core file.  The information should be formatted
+   in context64 form for both 32-bit and 64-bit process.
+   If successful return 0, else non-zero is returned.  */
+
+static int
+pdc_read_regs (pthdb_user_t user,
+               pthdb_tid_t tid,
+               unsigned long long flags,
+               pthdb_context_t *context)
+{
+  /* This function doesn't appear to be used, so we could probably
+   just return 0 here.  HOWEVER, if it is not defined, the OS will
+   complain and several thread debug functions will fail.  In case
+   this is needed, I have implemented what I think it should do,
+   however this code is untested.  */
+
+  uint64_t gprs64[ppc_num_gprs];
+  uint32_t gprs32[ppc_num_gprs];
+  double fprs[ppc_num_fprs];
+  struct ptxsprs sprs64;
+  struct ptsprs sprs32;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog, "pdc_read_regs tid=%d flags=%s\n",
+                        (int) tid, hex_string (flags));
+
+  /* General-purpose registers.  */
+  if (flags & PTHDB_FLAG_GPRS)
+    {
+      if (arch64)
+        {
+          if (!ptrace64aix (PTT_READ_GPRS, tid,
+                            (long long) gprs64, 0, NULL))
+            memset (gprs64, 0, sizeof (gprs64));
+          memcpy (context->gpr, gprs64, sizeof(gprs64));
+        }
+      else
+        {
+          if (!ptrace32 (PTT_READ_GPRS, (long long) tid, gprs32, 0, NULL))
+            memset (gprs32, 0, sizeof (gprs32));
+          memcpy (context->gpr, gprs32, sizeof(gprs32));
+        }
+    }
+
+  /* Floating-point registers.  */
+  if (flags & PTHDB_FLAG_FPRS)
+    {
+      if (!ptrace32 (PTT_READ_FPRS, tid, (long long) fprs, 0, NULL))
+        memset (fprs, 0, sizeof (fprs));
+      memcpy (context->fpr, fprs, sizeof(fprs));
+    }
+
+  /* Special-purpose registers.  */
+  if (flags & PTHDB_FLAG_SPRS)
+    {
+      if (arch64)
+        {
+          if (!ptrace64aix (PTT_READ_SPRS, tid,
+                            (long long) &sprs64, 0, NULL))
+            memset (&sprs64, 0, sizeof (sprs64));
+          memcpy (&context->msr, &sprs64, sizeof(sprs64));
+        }
+      else
+        {
+          if (!ptrace32 (PTT_READ_SPRS, tid, (long long) &sprs32, 0, NULL))
+            memset (&sprs32, 0, sizeof (sprs32));
+          memcpy (&context->msr, &sprs32, sizeof(sprs32));
+        }
+    }
+  return 0;
+}
+
+/* Write register function should be able to write requested context
+   information to specified debuggee's kernel thread id.
+   If successful return 0, else non-zero is returned.  */
+
+static int
+pdc_write_regs (pthdb_user_t user,
+                pthdb_tid_t tid,
+                unsigned long long flags,
+                pthdb_context_t *context)
+{
+  /* This function doesn't appear to be used, so we could probably
+     just return 0 here.  HOWEVER, if it is not defined, the OS will
+     complain and several thread debug functions will fail.  In case
+     this is needed, I have implemented what I think it should do,
+     however this code is untested.  */
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog, "pdc_write_regs tid=%d flags=%s\n",
+                        (int) tid, hex_string (flags));
+
+  /* General-purpose registers.  */
+  if (flags & PTHDB_FLAG_GPRS)
+    {
+      if (arch64)
+        ptrace64aix (PTT_WRITE_GPRS, tid,
+                     (long long) context->gpr, 0, NULL);
+      else
+        ptrace32 (PTT_WRITE_GPRS, tid, (long long) context->gpr, 0, NULL);
+    }
+
+ /* Floating-point registers.  */
+  if (flags & PTHDB_FLAG_FPRS)
+    {
+      ptrace32 (PTT_WRITE_FPRS, tid, (long long) context->fpr, 0, NULL);
+    }
+
+  /* Special-purpose registers.  */
+  if (flags & PTHDB_FLAG_SPRS)
+    {
+      if (arch64)
+        {
+          ptrace64aix (PTT_WRITE_SPRS, tid,
+                       (long long) &context->msr, 0, NULL);
+        }
+      else
+        {
+          ptrace32 (PTT_WRITE_SPRS, tid, (long long) &context->msr, 0, NULL);
+        }
+    }
+  return 0;
+}
+
+/* pthdb callback: read LEN bytes from process ADDR into BUF.  */
+
+static int
+pdc_read_data (pthdb_user_t user, void *buf,
+               pthdb_addr_t addr, size_t len)
+{
+  int status, ret;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+      "pdc_read_data (user = %ld, buf = 0x%lx, addr = %s, len = %ld)\n",
+      user, (long) buf, hex_string (addr), len);
+
+  status = target_read_memory (addr, buf, len);
+  ret = status == 0 ? PDC_SUCCESS : PDC_FAILURE;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog, "  status=%d, returning %s\n",
+                        status, pd_status2str (ret));
+  return ret;
+}
+
+/* pthdb callback: write LEN bytes from BUF to process ADDR.  */
+
+static int
+pdc_write_data (pthdb_user_t user, void *buf,
+                pthdb_addr_t addr, size_t len)
+{
+  int status, ret;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+      "pdc_write_data (user = %ld, buf = 0x%lx, addr = %s, len = %ld)\n",
+      user, (long) buf, hex_string (addr), len);
+
+  status = target_write_memory (addr, buf, len);
+  ret = status == 0 ? PDC_SUCCESS : PDC_FAILURE;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog, "  status=%d, returning %s\n", status,
+                        pd_status2str (ret));
+  return ret;
+}
+
+/* pthdb callback: allocate a LEN-byte buffer and store a pointer to it
+   in BUFP.  */
+
+static int
+pdc_alloc (pthdb_user_t user, size_t len, void **bufp)
+{
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+                        "pdc_alloc (user = %ld, len = %ld, bufp = 0x%lx)\n",
+                        user, len, (long) bufp);
+  *bufp = xmalloc (len);
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+                        "  malloc returned 0x%lx\n", (long) *bufp);
+
+  /* Note: xmalloc() can't return 0; therefore PDC_FAILURE will never
+     be returned.  */
+
+  return *bufp ? PDC_SUCCESS : PDC_FAILURE;
+}
+
+/* pthdb callback: reallocate BUF, which was allocated by the alloc or
+   realloc callback, so that it contains LEN bytes, and store a
+   pointer to the result in BUFP.  */
+
+static int
+pdc_realloc (pthdb_user_t user, void *buf, size_t len, void **bufp)
+{
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+      "pdc_realloc (user = %ld, buf = 0x%lx, len = %ld, bufp = 0x%lx)\n",
+      user, (long) buf, len, (long) bufp);
+  *bufp = xrealloc (buf, len);
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+                        "  realloc returned 0x%lx\n", (long) *bufp);
+  return *bufp ? PDC_SUCCESS : PDC_FAILURE;
+}
+
+/* pthdb callback: free BUF, which was allocated by the alloc or
+   realloc callback.  */
+
+static int
+pdc_dealloc (pthdb_user_t user, void *buf)
+{
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+                        "pdc_free (user = %ld, buf = 0x%lx)\n", user,
+                        (long) buf);
+  xfree (buf);
+  return PDC_SUCCESS;
+}
+
+/* Return a printable representation of pthread STATE.  */
+
+static char *
+state2str (pthdb_state_t state)
+{
+  switch (state)
+    {
+    case PST_IDLE:
+      /* i18n: Like "Thread-Id %d, [state] idle" */
+      return _("idle");      /* being created */
+    case PST_RUN:
+      /* i18n: Like "Thread-Id %d, [state] running" */
+      return _("running");   /* running */
+    case PST_SLEEP:
+      /* i18n: Like "Thread-Id %d, [state] sleeping" */
+      return _("sleeping");  /* awaiting an event */
+    case PST_READY:
+      /* i18n: Like "Thread-Id %d, [state] ready" */
+      return _("ready");     /* runnable */
+    case PST_TERM:
+      /* i18n: Like "Thread-Id %d, [state] finished" */
+      return _("finished");  /* awaiting a join/detach */
+    default:
+      /* i18n: Like "Thread-Id %d, [state] unknown" */
+      return _("unknown");
+    }
+}
+
+/* qsort() comparison function for sorting pd_thread structs by pthid.  */
+
+static int
+pcmp (const void *p1v, const void *p2v)
+{
+  struct pd_thread *p1 = (struct pd_thread *) p1v;
+  struct pd_thread *p2 = (struct pd_thread *) p2v;
+  return p1->pthid < p2->pthid ? -1 : p1->pthid > p2->pthid;
+}
+
+/* iterate_over_threads() callback for counting GDB threads.
+
+   Do not count the main thread (whose tid is zero).  This matches
+   the list of threads provided by the pthreaddebug library, which
+   does not include that main thread either, and thus allows us
+   to compare the two lists.  */
+
+static int
+giter_count (struct thread_info *thread, void *countp)
+{
+  if (PD_TID (thread->ptid))
+    (*(int *) countp)++;
+  return 0;
+}
+
+/* iterate_over_threads() callback for accumulating GDB thread pids.
+
+   Do not include the main thread (whose tid is zero).  This matches
+   the list of threads provided by the pthreaddebug library, which
+   does not include that main thread either, and thus allows us
+   to compare the two lists.  */
+
+static int
+giter_accum (struct thread_info *thread, void *bufp)
+{
+  if (PD_TID (thread->ptid))
+    {
+      **(struct thread_info ***) bufp = thread;
+      (*(struct thread_info ***) bufp)++;
+    }
+  return 0;
+}
+
+/* ptid comparison function */
+
+static int
+ptid_cmp (ptid_t ptid1, ptid_t ptid2)
+{
+  int pid1, pid2;
+
+  if (ptid_get_pid (ptid1) < ptid_get_pid (ptid2))
+    return -1;
+  else if (ptid_get_pid (ptid1) > ptid_get_pid (ptid2))
+    return 1;
+  else if (ptid_get_tid (ptid1) < ptid_get_tid (ptid2))
+    return -1;
+  else if (ptid_get_tid (ptid1) > ptid_get_tid (ptid2))
+    return 1;
+  else if (ptid_get_lwp (ptid1) < ptid_get_lwp (ptid2))
+    return -1;
+  else if (ptid_get_lwp (ptid1) > ptid_get_lwp (ptid2))
+    return 1;
+  else
+    return 0;
+}
+
+/* qsort() comparison function for sorting thread_info structs by pid.  */
+
+static int
+gcmp (const void *t1v, const void *t2v)
+{
+  struct thread_info *t1 = *(struct thread_info **) t1v;
+  struct thread_info *t2 = *(struct thread_info **) t2v;
+  return ptid_cmp (t1->ptid, t2->ptid);
+}
+
+/* Search through the list of all kernel threads for the thread
+   that has stopped on a SIGTRAP signal, and return its TID.
+   Return 0 if none found.  */
+
+static pthdb_tid_t
+get_signaled_thread (void)
+{
+  struct thrdsinfo64 thrinf;
+  pthdb_tid_t ktid = 0;
+  int result = 0;
+
+  while (1)
+  {
+    if (getthrds (PIDGET (inferior_ptid), &thrinf,
+                  sizeof (thrinf), &ktid, 1) != 1)
+      break;
+
+    if (thrinf.ti_cursig == SIGTRAP)
+      return thrinf.ti_tid;
+  }
+
+  /* Didn't find any thread stopped on a SIGTRAP signal.  */
+  return 0;
+}
+
+/* Synchronize GDB's thread list with libpthdebug's.
+
+   There are some benefits of doing this every time the inferior stops:
+
+     - allows users to run thread-specific commands without needing to
+       run "info threads" first
+
+     - helps pthdb_tid_pthread() work properly (see "libpthdebug
+       peculiarities" at the top of this module)
+
+     - simplifies the demands placed on libpthdebug, which seems to
+       have difficulty with certain call patterns */
+
+static void
+sync_threadlists (void)
+{
+  int cmd, status, infpid;
+  int pcount, psize, pi, gcount, gi;
+  struct pd_thread *pbuf;
+  struct thread_info **gbuf, **g, *thread;
+  pthdb_pthread_t pdtid;
+  pthread_t pthid;
+  pthdb_tid_t tid;
+
+  /* Accumulate an array of libpthdebug threads sorted by pthread id.  */
+
+  pcount = 0;
+  psize = 1;
+  pbuf = (struct pd_thread *) xmalloc (psize * sizeof *pbuf);
+
+  for (cmd = PTHDB_LIST_FIRST;; cmd = PTHDB_LIST_NEXT)
+    {
+      status = pthdb_pthread (pd_session, &pdtid, cmd);
+      if (status != PTHDB_SUCCESS || pdtid == PTHDB_INVALID_PTHREAD)
+        break;
+
+      status = pthdb_pthread_ptid (pd_session, pdtid, &pthid);
+      if (status != PTHDB_SUCCESS || pthid == PTHDB_INVALID_PTID)
+        continue;
+
+      if (pcount == psize)
+        {
+          psize *= 2;
+          pbuf = (struct pd_thread *) xrealloc (pbuf,
+                                                psize * sizeof *pbuf);
+        }
+      pbuf[pcount].pdtid = pdtid;
+      pbuf[pcount].pthid = pthid;
+      pcount++;
+    }
+
+  for (pi = 0; pi < pcount; pi++)
+    {
+      status = pthdb_pthread_tid (pd_session, pbuf[pi].pdtid, &tid);
+      if (status != PTHDB_SUCCESS)
+        tid = PTHDB_INVALID_TID;
+      pbuf[pi].tid = tid;
+    }
+
+  qsort (pbuf, pcount, sizeof *pbuf, pcmp);
+
+  /* Accumulate an array of GDB threads sorted by pid.  */
+
+  gcount = 0;
+  iterate_over_threads (giter_count, &gcount);
+  g = gbuf = (struct thread_info **) xmalloc (gcount * sizeof *gbuf);
+  iterate_over_threads (giter_accum, &g);
+  qsort (gbuf, gcount, sizeof *gbuf, gcmp);
+
+  /* Apply differences between the two arrays to GDB's thread list.  */
+
+  infpid = PIDGET (inferior_ptid);
+  for (pi = gi = 0; pi < pcount || gi < gcount;)
+    {
+      if (pi == pcount)
+        {
+          delete_thread (gbuf[gi]->ptid);
+          gi++;
+        }
+      else if (gi == gcount)
+        {
+          thread = add_thread (BUILD_THREAD (pbuf[pi].pthid, infpid));
+          thread->private = xmalloc (sizeof (struct private_thread_info));
+          thread->private->pdtid = pbuf[pi].pdtid;
+          thread->private->tid = pbuf[pi].tid;
+          pi++;
+        }
+      else
+        {
+          ptid_t pptid, gptid;
+          int cmp_result;
+
+          pptid = BUILD_THREAD (pbuf[pi].pthid, infpid);
+          gptid = gbuf[gi]->ptid;
+          pdtid = pbuf[pi].pdtid;
+          tid = pbuf[pi].tid;
+
+          cmp_result = ptid_cmp (pptid, gptid);
+
+          if (cmp_result == 0)
+            {
+              gbuf[gi]->private->pdtid = pdtid;
+              gbuf[gi]->private->tid = tid;
+              pi++;
+              gi++;
+            }
+          else if (cmp_result > 0)
+            {
+              delete_thread (gptid);
+              gi++;
+            }
+          else
+            {
+              thread = add_thread (pptid);
+              thread->private = xmalloc (sizeof (struct private_thread_info));
+              thread->private->pdtid = pdtid;
+              thread->private->tid = tid;
+              pi++;
+            }
+        }
+    }
+
+  xfree (pbuf);
+  xfree (gbuf);
+}
+
+/* Iterate_over_threads() callback for locating a thread, using
+   the TID of its associated kernel thread.  */
+
+static int
+iter_tid (struct thread_info *thread, void *tidp)
+{
+  const pthdb_tid_t tid = *(pthdb_tid_t *)tidp;
+
+  return (thread->private->tid == tid);
+}
+
+/* Synchronize libpthdebug's state with the inferior and with GDB,
+   generate a composite process/thread <pid> for the current thread,
+   set inferior_ptid to <pid> if SET_INFPID, and return <pid>.  */
+
+static ptid_t
+pd_update (int set_infpid)
+{
+  int status;
+  ptid_t ptid;
+  pthdb_tid_t tid;
+  struct thread_info *thread = NULL;
+
+  if (!pd_active)
+    return inferior_ptid;
+
+  status = pthdb_session_update (pd_session);
+  if (status != PTHDB_SUCCESS)
+    return inferior_ptid;
+
+  sync_threadlists ();
+
+  /* Define "current thread" as one that just received a trap signal.  */
+
+  tid = get_signaled_thread ();
+  if (tid != 0)
+    thread = iterate_over_threads (iter_tid, &tid);
+  if (!thread)
+    ptid = inferior_ptid;
+  else
+    {
+      ptid = thread->ptid;
+      if (set_infpid)
+        inferior_ptid = ptid;
+    }
+  return ptid;
+}
+
+/* Try to start debugging threads in the current process.
+   If successful and SET_INFPID, set inferior_ptid to reflect the
+   current thread.  */
+
+static ptid_t
+pd_activate (int set_infpid)
+{
+  int status;
+
+  status = pthdb_session_init (PD_USER, arch64 ? PEM_64BIT : PEM_32BIT,
+                               PTHDB_FLAG_REGS, &pd_callbacks,
+                               &pd_session);
+  if (status != PTHDB_SUCCESS)
+    {
+      return inferior_ptid;
+    }
+  pd_active = 1;
+  return pd_update (set_infpid);
+}
+
+/* Undo the effects of pd_activate().  */
+
+static void
+pd_deactivate (void)
+{
+  if (!pd_active)
+    return;
+  pthdb_session_destroy (pd_session);
+
+  pid_to_prc (&inferior_ptid);
+  pd_active = 0;
+}
+
+/* An object file has just been loaded.  Check whether the current
+   application is pthreaded, and if so, prepare for thread debugging.  */
+
+static void
+pd_enable (void)
+{
+  int status;
+  char *stub_name;
+  struct minimal_symbol *ms;
+
+  /* Don't initialize twice.  */
+  if (pd_able)
+    return;
+
+  /* Check application word size.  */
+  arch64 = register_size (target_gdbarch, 0) == 8;
+
+  /* Check whether the application is pthreaded.  */
+  stub_name = NULL;
+  status = pthdb_session_pthreaded (PD_USER, PTHDB_FLAG_REGS,
+                                    &pd_callbacks, &stub_name);
+  if ((status != PTHDB_SUCCESS
+       && status != PTHDB_NOT_PTHREADED) || !stub_name)
+    return;
+
+  /* Set a breakpoint on the returned stub function.  */
+  if (!(ms = lookup_minimal_symbol (stub_name, NULL, NULL)))
+    return;
+  pd_brk_addr = SYMBOL_VALUE_ADDRESS (ms);
+  if (!create_thread_event_breakpoint (target_gdbarch, pd_brk_addr))
+    return;
+
+  /* Prepare for thread debugging.  */
+  push_target (&aix_thread_ops);
+  pd_able = 1;
+
+  /* If we're debugging a core file or an attached inferior, the
+     pthread library may already have been initialized, so try to
+     activate thread debugging.  */
+  pd_activate (1);
+}
+
+/* Undo the effects of pd_enable().  */
+
+static void
+pd_disable (void)
+{
+  if (!pd_able)
+    return;
+  if (pd_active)
+    pd_deactivate ();
+  pd_able = 0;
+  unpush_target (&aix_thread_ops);
+}
+
+/* new_objfile observer callback.
+
+   If OBJFILE is non-null, check whether a threaded application is
+   being debugged, and if so, prepare for thread debugging.
+
+   If OBJFILE is null, stop debugging threads.  */
+
+static void
+new_objfile (struct objfile *objfile)
+{
+  if (objfile)
+    pd_enable ();
+  else
+    pd_disable ();
+}
+
+/* Attach to process specified by ARGS.  */
+
+static void
+aix_thread_attach (struct target_ops *ops, char *args, int from_tty)
+{
+  struct target_ops *beneath = find_target_beneath (ops);
+
+  beneath->to_attach (beneath, args, from_tty);
+  pd_activate (1);
+}
+
+/* Detach from the process attached to by aix_thread_attach().  */
+
+static void
+aix_thread_detach (struct target_ops *ops, char *args, int from_tty)
+{
+  struct target_ops *beneath = find_target_beneath (ops);
+
+  pd_disable ();
+  beneath->to_detach (beneath, args, from_tty);
+}
+
+/* Tell the inferior process to continue running thread PID if != -1
+   and all threads otherwise.  */
+
+static void
+aix_thread_resume (struct target_ops *ops,
+                   ptid_t ptid, int step, enum gdb_signal sig)
+{
+  struct thread_info *thread;
+  pthdb_tid_t tid[2];
+
+  if (!PD_TID (ptid))
+    {
+      struct cleanup *cleanup = save_inferior_ptid ();
+      struct target_ops *beneath = find_target_beneath (ops);
+
+      inferior_ptid = pid_to_ptid (PIDGET (inferior_ptid));
+      beneath->to_resume (beneath, ptid, step, sig);
+      do_cleanups (cleanup);
+    }
+  else
+    {
+      thread = find_thread_ptid (ptid);
+      if (!thread)
+        error (_("aix-thread resume: unknown pthread %ld"),
+               TIDGET (ptid));
+
+      tid[0] = thread->private->tid;
+      if (tid[0] == PTHDB_INVALID_TID)
+        error (_("aix-thread resume: no tid for pthread %ld"),
+               TIDGET (ptid));
+      tid[1] = 0;
+
+      if (arch64)
+        ptrace64aix (PTT_CONTINUE, tid[0], (long long) 1,
+                     gdb_signal_to_host (sig), (void *) tid);
+      else
+        ptrace32 (PTT_CONTINUE, tid[0], (long long) 1,
+                  gdb_signal_to_host (sig), (void *) tid);
+    }
+}
+
+/* Wait for thread/process ID if != -1 or for any thread otherwise.
+   If an error occurs, return -1, else return the pid of the stopped
+   thread.  */
+
+static ptid_t
+aix_thread_wait (struct target_ops *ops,
+                 ptid_t ptid, struct target_waitstatus *status, int options)
+{
+  struct cleanup *cleanup = save_inferior_ptid ();
+  struct target_ops *beneath = find_target_beneath (ops);
+
+  pid_to_prc (&ptid);
+
+  inferior_ptid = pid_to_ptid (PIDGET (inferior_ptid));
+  ptid = beneath->to_wait (beneath, ptid, status, options);
+  do_cleanups (cleanup);
+
+  if (PIDGET (ptid) == -1)
+    return pid_to_ptid (-1);
+
+  /* Check whether libpthdebug might be ready to be initialized.  */
+  if (!pd_active && status->kind == TARGET_WAITKIND_STOPPED
+      && status->value.sig == GDB_SIGNAL_TRAP)
+    {
+      struct regcache *regcache = get_thread_regcache (ptid);
+      struct gdbarch *gdbarch = get_regcache_arch (regcache);
+
+      if (regcache_read_pc (regcache)
+          - gdbarch_decr_pc_after_break (gdbarch) == pd_brk_addr)
+        return pd_activate (0);
+    }
+
+  return pd_update (0);
+}
+
+/* Record that the 64-bit general-purpose registers contain VALS.  */
+
+static void
+supply_gprs64 (struct regcache *regcache, uint64_t *vals)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache));
+  int regno;
+
+  for (regno = 0; regno < ppc_num_gprs; regno++)
+    regcache_raw_supply (regcache, tdep->ppc_gp0_regnum + regno,
+                         (char *) (vals + regno));
+}
+
+/* Record that 32-bit register REGNO contains VAL.  */
+
+static void
+supply_reg32 (struct regcache *regcache, int regno, uint32_t val)
+{
+  regcache_raw_supply (regcache, regno, (char *) &val);
+}
+
+/* Record that the floating-point registers contain VALS.  */
+
+static void
+supply_fprs (struct regcache *regcache, double *vals)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  int regno;
+
+  /* This function should never be called on architectures without
+     floating-point registers.  */
+  gdb_assert (ppc_floating_point_unit_p (gdbarch));
+
+  for (regno = tdep->ppc_fp0_regnum;
+       regno < tdep->ppc_fp0_regnum + ppc_num_fprs;
+       regno++)
+    regcache_raw_supply (regcache, regno,
+                         (char *) (vals + regno - tdep->ppc_fp0_regnum));
+}
+
+/* Predicate to test whether given register number is a "special" register.  */
+static int
+special_register_p (struct gdbarch *gdbarch, int regno)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  return regno == gdbarch_pc_regnum (gdbarch)
+      || regno == tdep->ppc_ps_regnum
+      || regno == tdep->ppc_cr_regnum
+      || regno == tdep->ppc_lr_regnum
+      || regno == tdep->ppc_ctr_regnum
+      || regno == tdep->ppc_xer_regnum
+      || (tdep->ppc_fpscr_regnum >= 0 && regno == tdep->ppc_fpscr_regnum)
+      || (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum);
+}
+
+
+/* Record that the special registers contain the specified 64-bit and
+   32-bit values.  */
+
+static void
+supply_sprs64 (struct regcache *regcache,
+               uint64_t iar, uint64_t msr, uint32_t cr,
+               uint64_t lr, uint64_t ctr, uint32_t xer,
+               uint32_t fpscr)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  regcache_raw_supply (regcache, gdbarch_pc_regnum (gdbarch),
+                       (char *) &iar);
+  regcache_raw_supply (regcache, tdep->ppc_ps_regnum, (char *) &msr);
+  regcache_raw_supply (regcache, tdep->ppc_cr_regnum, (char *) &cr);
+  regcache_raw_supply (regcache, tdep->ppc_lr_regnum, (char *) &lr);
+  regcache_raw_supply (regcache, tdep->ppc_ctr_regnum, (char *) &ctr);
+  regcache_raw_supply (regcache, tdep->ppc_xer_regnum, (char *) &xer);
+  if (tdep->ppc_fpscr_regnum >= 0)
+    regcache_raw_supply (regcache, tdep->ppc_fpscr_regnum,
+                         (char *) &fpscr);
+}
+
+/* Record that the special registers contain the specified 32-bit
+   values.  */
+
+static void
+supply_sprs32 (struct regcache *regcache,
+               uint32_t iar, uint32_t msr, uint32_t cr,
+               uint32_t lr, uint32_t ctr, uint32_t xer,
+               uint32_t fpscr)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  regcache_raw_supply (regcache, gdbarch_pc_regnum (gdbarch),
+                       (char *) &iar);
+  regcache_raw_supply (regcache, tdep->ppc_ps_regnum, (char *) &msr);
+  regcache_raw_supply (regcache, tdep->ppc_cr_regnum, (char *) &cr);
+  regcache_raw_supply (regcache, tdep->ppc_lr_regnum, (char *) &lr);
+  regcache_raw_supply (regcache, tdep->ppc_ctr_regnum, (char *) &ctr);
+  regcache_raw_supply (regcache, tdep->ppc_xer_regnum, (char *) &xer);
+  if (tdep->ppc_fpscr_regnum >= 0)
+    regcache_raw_supply (regcache, tdep->ppc_fpscr_regnum,
+                         (char *) &fpscr);
+}
+
+/* Fetch all registers from pthread PDTID, which doesn't have a kernel
+   thread.
+
+   There's no way to query a single register from a non-kernel
+   pthread, so there's no need for a single-register version of this
+   function.  */
+
+static void
+fetch_regs_user_thread (struct regcache *regcache, pthdb_pthread_t pdtid)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  int status, i;
+  pthdb_context_t ctx;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+                        "fetch_regs_user_thread %lx\n", (long) pdtid);
+  status = pthdb_pthread_context (pd_session, pdtid, &ctx);
+  if (status != PTHDB_SUCCESS)
+    error (_("aix-thread: fetch_registers: pthdb_pthread_context returned %s"),
+           pd_status2str (status));
+
+  /* General-purpose registers.  */
+
+  if (arch64)
+    supply_gprs64 (regcache, ctx.gpr);
+  else
+    for (i = 0; i < ppc_num_gprs; i++)
+      supply_reg32 (regcache, tdep->ppc_gp0_regnum + i, ctx.gpr[i]);
+
+  /* Floating-point registers.  */
+
+  if (ppc_floating_point_unit_p (gdbarch))
+    supply_fprs (regcache, ctx.fpr);
+
+  /* Special registers.  */
+
+  if (arch64)
+    supply_sprs64 (regcache, ctx.iar, ctx.msr, ctx.cr, ctx.lr, ctx.ctr,
+                             ctx.xer, ctx.fpscr);
+  else
+    supply_sprs32 (regcache, ctx.iar, ctx.msr, ctx.cr, ctx.lr, ctx.ctr,
+                             ctx.xer, ctx.fpscr);
+}
+
+/* Fetch register REGNO if != -1 or all registers otherwise from
+   kernel thread TID.
+
+   AIX provides a way to query all of a kernel thread's GPRs, FPRs, or
+   SPRs, but there's no way to query individual registers within those
+   groups.  Therefore, if REGNO != -1, this function fetches an entire
+   group.
+
+   Unfortunately, kernel thread register queries often fail with
+   EPERM, indicating that the thread is in kernel space.  This breaks
+   backtraces of threads other than the current one.  To make that
+   breakage obvious without throwing an error to top level (which is
+   bad e.g. during "info threads" output), zero registers that can't
+   be retrieved.  */
+
+static void
+fetch_regs_kernel_thread (struct regcache *regcache, int regno,
+                          pthdb_tid_t tid)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  uint64_t gprs64[ppc_num_gprs];
+  uint32_t gprs32[ppc_num_gprs];
+  double fprs[ppc_num_fprs];
+  struct ptxsprs sprs64;
+  struct ptsprs sprs32;
+  int i;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+        "fetch_regs_kernel_thread tid=%lx regno=%d arch64=%d\n",
+        (long) tid, regno, arch64);
+
+  /* General-purpose registers.  */
+  if (regno == -1
+      || (tdep->ppc_gp0_regnum <= regno
+          && regno < tdep->ppc_gp0_regnum + ppc_num_gprs))
+    {
+      if (arch64)
+        {
+          if (!ptrace64aix (PTT_READ_GPRS, tid,
+                            (long long) gprs64, 0, NULL))
+            memset (gprs64, 0, sizeof (gprs64));
+          supply_gprs64 (regcache, gprs64);
+        }
+      else
+        {
+          if (!ptrace32 (PTT_READ_GPRS, tid, (long long) gprs32, 0, NULL))
+            memset (gprs32, 0, sizeof (gprs32));
+          for (i = 0; i < ppc_num_gprs; i++)
+            supply_reg32 (regcache, tdep->ppc_gp0_regnum + i, gprs32[i]);
+        }
+    }
+
+  /* Floating-point registers.  */
+
+  if (ppc_floating_point_unit_p (gdbarch)
+      && (regno == -1
+          || (regno >= tdep->ppc_fp0_regnum
+              && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)))
+    {
+      if (!ptrace32 (PTT_READ_FPRS, tid, (long long) fprs, 0, NULL))
+        memset (fprs, 0, sizeof (fprs));
+      supply_fprs (regcache, fprs);
+    }
+
+  /* Special-purpose registers.  */
+
+  if (regno == -1 || special_register_p (gdbarch, regno))
+    {
+      if (arch64)
+        {
+          if (!ptrace64aix (PTT_READ_SPRS, tid,
+                            (long long) &sprs64, 0, NULL))
+            memset (&sprs64, 0, sizeof (sprs64));
+          supply_sprs64 (regcache, sprs64.pt_iar, sprs64.pt_msr,
+                         sprs64.pt_cr, sprs64.pt_lr, sprs64.pt_ctr,
+                         sprs64.pt_xer, sprs64.pt_fpscr);
+        }
+      else
+        {
+          struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+          if (!ptrace32 (PTT_READ_SPRS, tid, (long long) &sprs32, 0, NULL))
+            memset (&sprs32, 0, sizeof (sprs32));
+          supply_sprs32 (regcache, sprs32.pt_iar, sprs32.pt_msr, sprs32.pt_cr,
+                         sprs32.pt_lr, sprs32.pt_ctr, sprs32.pt_xer,
+                         sprs32.pt_fpscr);
+
+          if (tdep->ppc_mq_regnum >= 0)
+            regcache_raw_supply (regcache, tdep->ppc_mq_regnum,
+                                 (char *) &sprs32.pt_mq);
+        }
+    }
+}
+
+/* Fetch register REGNO if != -1 or all registers otherwise in the
+   thread/process specified by inferior_ptid.  */
+
+static void
+aix_thread_fetch_registers (struct target_ops *ops,
+                            struct regcache *regcache, int regno)
+{
+  struct thread_info *thread;
+  pthdb_tid_t tid;
+  struct target_ops *beneath = find_target_beneath (ops);
+
+  if (!PD_TID (inferior_ptid))
+    beneath->to_fetch_registers (beneath, regcache, regno);
+  else
+    {
+      thread = find_thread_ptid (inferior_ptid);
+      tid = thread->private->tid;
+
+      if (tid == PTHDB_INVALID_TID)
+        fetch_regs_user_thread (regcache, thread->private->pdtid);
+      else
+        fetch_regs_kernel_thread (regcache, regno, tid);
+    }
+}
+
+/* Store the gp registers into an array of uint32_t or uint64_t.  */
+
+static void
+fill_gprs64 (const struct regcache *regcache, uint64_t *vals)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache));
+  int regno;
+
+  for (regno = 0; regno < ppc_num_gprs; regno++)
+    if (REG_VALID == regcache_register_status (regcache,
+                                               tdep->ppc_gp0_regnum + regno))
+      regcache_raw_collect (regcache, tdep->ppc_gp0_regnum + regno,
+                            vals + regno);
+}
+
+static void
+fill_gprs32 (const struct regcache *regcache, uint32_t *vals)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_regcache_arch (regcache));
+  int regno;
+
+  for (regno = 0; regno < ppc_num_gprs; regno++)
+    if (REG_VALID == regcache_register_status (regcache,
+                                               tdep->ppc_gp0_regnum + regno))
+      regcache_raw_collect (regcache, tdep->ppc_gp0_regnum + regno,
+                            vals + regno);
+}
+
+/* Store the floating point registers into a double array.  */
+static void
+fill_fprs (const struct regcache *regcache, double *vals)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  int regno;
+
+  /* This function should never be called on architectures without
+     floating-point registers.  */
+  gdb_assert (ppc_floating_point_unit_p (gdbarch));
+
+  for (regno = tdep->ppc_fp0_regnum;
+       regno < tdep->ppc_fp0_regnum + ppc_num_fprs;
+       regno++)
+    if (REG_VALID == regcache_register_status (regcache, regno))
+      regcache_raw_collect (regcache, regno,
+                            vals + regno - tdep->ppc_fp0_regnum);
+}
+
+/* Store the special registers into the specified 64-bit and 32-bit
+   locations.  */
+
+static void
+fill_sprs64 (const struct regcache *regcache,
+             uint64_t *iar, uint64_t *msr, uint32_t *cr,
+             uint64_t *lr, uint64_t *ctr, uint32_t *xer,
+             uint32_t *fpscr)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  /* Verify that the size of the size of the IAR buffer is the
+     same as the raw size of the PC (in the register cache).  If
+     they're not, then either GDB has been built incorrectly, or
+     there's some other kind of internal error.  To be really safe,
+     we should check all of the sizes.   */
+  gdb_assert (sizeof (*iar) == register_size
+                                 (gdbarch, gdbarch_pc_regnum (gdbarch)));
+
+  if (REG_VALID == regcache_register_status (regcache,
+                                             gdbarch_pc_regnum (gdbarch)))
+    regcache_raw_collect (regcache, gdbarch_pc_regnum (gdbarch), iar);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_ps_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_ps_regnum, msr);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_cr_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_cr_regnum, cr);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_lr_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_lr_regnum, lr);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_ctr_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_ctr_regnum, ctr);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_xer_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_xer_regnum, xer);
+  if (tdep->ppc_fpscr_regnum >= 0
+      && REG_VALID == regcache_register_status (regcache,
+                                                tdep->ppc_fpscr_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_fpscr_regnum, fpscr);
+}
+
+static void
+fill_sprs32 (const struct regcache *regcache,
+             uint32_t *iar, uint32_t *msr, uint32_t *cr,
+             uint32_t *lr, uint32_t *ctr, uint32_t *xer,
+             uint32_t *fpscr)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  /* Verify that the size of the size of the IAR buffer is the
+     same as the raw size of the PC (in the register cache).  If
+     they're not, then either GDB has been built incorrectly, or
+     there's some other kind of internal error.  To be really safe,
+     we should check all of the sizes.  */
+  gdb_assert (sizeof (*iar) == register_size (gdbarch,
+                                              gdbarch_pc_regnum (gdbarch)));
+
+  if (REG_VALID == regcache_register_status (regcache,
+                                             gdbarch_pc_regnum (gdbarch)))
+    regcache_raw_collect (regcache, gdbarch_pc_regnum (gdbarch), iar);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_ps_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_ps_regnum, msr);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_cr_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_cr_regnum, cr);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_lr_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_lr_regnum, lr);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_ctr_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_ctr_regnum, ctr);
+  if (REG_VALID == regcache_register_status (regcache, tdep->ppc_xer_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_xer_regnum, xer);
+  if (tdep->ppc_fpscr_regnum >= 0
+      && REG_VALID == regcache_register_status (regcache, tdep->ppc_fpscr_regnum))
+    regcache_raw_collect (regcache, tdep->ppc_fpscr_regnum, fpscr);
+}
+
+/* Store all registers into pthread PDTID, which doesn't have a kernel
+   thread.
+
+   It's possible to store a single register into a non-kernel pthread,
+   but I doubt it's worth the effort.  */
+
+static void
+store_regs_user_thread (const struct regcache *regcache, pthdb_pthread_t pdtid)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  int status, i;
+  pthdb_context_t ctx;
+  uint32_t int32;
+  uint64_t int64;
+  double   dbl;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+                        "store_regs_user_thread %lx\n", (long) pdtid);
+
+  /* Retrieve the thread's current context for its non-register
+     values.  */
+  status = pthdb_pthread_context (pd_session, pdtid, &ctx);
+  if (status != PTHDB_SUCCESS)
+    error (_("aix-thread: store_registers: pthdb_pthread_context returned %s"),
+           pd_status2str (status));
+
+  /* Collect general-purpose register values from the regcache.  */
+
+  for (i = 0; i < ppc_num_gprs; i++)
+    if (REG_VALID == regcache_register_status (regcache,
+                                               tdep->ppc_gp0_regnum + i))
+      {
+        if (arch64)
+          {
+            regcache_raw_collect (regcache, tdep->ppc_gp0_regnum + i,
+                                  (void *) &int64);
+            ctx.gpr[i] = int64;
+          }
+        else
+          {
+            regcache_raw_collect (regcache, tdep->ppc_gp0_regnum + i,
+                                  (void *) &int32);
+            ctx.gpr[i] = int32;
+          }
+      }
+
+  /* Collect floating-point register values from the regcache.  */
+  if (ppc_floating_point_unit_p (gdbarch))
+    fill_fprs (regcache, ctx.fpr);
+
+  /* Special registers (always kept in ctx as 64 bits).  */
+  if (arch64)
+    {
+      fill_sprs64 (regcache, &ctx.iar, &ctx.msr, &ctx.cr, &ctx.lr, &ctx.ctr,
+                             &ctx.xer, &ctx.fpscr);
+    }
+  else
+    {
+      /* Problem: ctx.iar etc. are 64 bits, but raw_registers are 32.
+         Solution: use 32-bit temp variables.  */
+      uint32_t tmp_iar, tmp_msr, tmp_cr, tmp_lr, tmp_ctr, tmp_xer,
+               tmp_fpscr;
+
+      fill_sprs32 (regcache, &tmp_iar, &tmp_msr, &tmp_cr, &tmp_lr, &tmp_ctr,
+                             &tmp_xer, &tmp_fpscr);
+      if (REG_VALID == regcache_register_status (regcache,
+                                                 gdbarch_pc_regnum (gdbarch)))
+        ctx.iar = tmp_iar;
+      if (REG_VALID == regcache_register_status (regcache, tdep->ppc_ps_regnum))
+        ctx.msr = tmp_msr;
+      if (REG_VALID == regcache_register_status (regcache, tdep->ppc_cr_regnum))
+        ctx.cr  = tmp_cr;
+      if (REG_VALID == regcache_register_status (regcache, tdep->ppc_lr_regnum))
+        ctx.lr  = tmp_lr;
+      if (REG_VALID == regcache_register_status (regcache,
+                                                 tdep->ppc_ctr_regnum))
+        ctx.ctr = tmp_ctr;
+      if (REG_VALID == regcache_register_status (regcache,
+                                                 tdep->ppc_xer_regnum))
+        ctx.xer = tmp_xer;
+      if (REG_VALID == regcache_register_status (regcache,
+                                                 tdep->ppc_xer_regnum))
+        ctx.fpscr = tmp_fpscr;
+    }
+
+  status = pthdb_pthread_setcontext (pd_session, pdtid, &ctx);
+  if (status != PTHDB_SUCCESS)
+    error (_("aix-thread: store_registers: "
+             "pthdb_pthread_setcontext returned %s"),
+           pd_status2str (status));
+}
+
+/* Store register REGNO if != -1 or all registers otherwise into
+   kernel thread TID.
+
+   AIX provides a way to set all of a kernel thread's GPRs, FPRs, or
+   SPRs, but there's no way to set individual registers within those
+   groups.  Therefore, if REGNO != -1, this function stores an entire
+   group.  */
+
+static void
+store_regs_kernel_thread (const struct regcache *regcache, int regno,
+                          pthdb_tid_t tid)
+{
+  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  uint64_t gprs64[ppc_num_gprs];
+  uint32_t gprs32[ppc_num_gprs];
+  double fprs[ppc_num_fprs];
+  struct ptxsprs sprs64;
+  struct ptsprs  sprs32;
+  int i;
+
+  if (debug_aix_thread)
+    fprintf_unfiltered (gdb_stdlog,
+                        "store_regs_kernel_thread tid=%lx regno=%d\n",
+                        (long) tid, regno);
+
+  /* General-purpose registers.  */
+  if (regno == -1
+      || (tdep->ppc_gp0_regnum <= regno
+          && regno < tdep->ppc_gp0_regnum + ppc_num_fprs))
+    {
+      if (arch64)
+        {
+          /* Pre-fetch: some regs may not be in the cache.  */
+          ptrace64aix (PTT_READ_GPRS, tid, (long long) gprs64, 0, NULL);
+          fill_gprs64 (regcache, gprs64);
+          ptrace64aix (PTT_WRITE_GPRS, tid, (long long) gprs64, 0, NULL);
+        }
+      else
+        {
+          /* Pre-fetch: some regs may not be in the cache.  */
+          ptrace32 (PTT_READ_GPRS, tid, (long long) gprs32, 0, NULL);
+          fill_gprs32 (regcache, gprs32);
+          ptrace32 (PTT_WRITE_GPRS, tid, (long long) gprs32, 0, NULL);
+        }
+    }
+
+  /* Floating-point registers.  */
+
+  if (ppc_floating_point_unit_p (gdbarch)
+      && (regno == -1
+          || (regno >= tdep->ppc_fp0_regnum
+              && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)))
+    {
+      /* Pre-fetch: some regs may not be in the cache.  */
+      ptrace32 (PTT_READ_FPRS, tid, (long long) fprs, 0, NULL);
+      fill_fprs (regcache, fprs);
+      ptrace32 (PTT_WRITE_FPRS, tid, (long long) fprs, 0, NULL);
+    }
+
+  /* Special-purpose registers.  */
+
+  if (regno == -1 || special_register_p (gdbarch, regno))
+    {
+      if (arch64)
+        {
+          /* Pre-fetch: some registers won't be in the cache.  */
+          ptrace64aix (PTT_READ_SPRS, tid,
+                       (long long) &sprs64, 0, NULL);
+          fill_sprs64 (regcache, &sprs64.pt_iar, &sprs64.pt_msr,
+                       &sprs64.pt_cr, &sprs64.pt_lr, &sprs64.pt_ctr,
+                       &sprs64.pt_xer, &sprs64.pt_fpscr);
+          ptrace64aix (PTT_WRITE_SPRS, tid,
+                       (long long) &sprs64, 0, NULL);
+        }
+      else
+        {
+          /* The contents of "struct ptspr" were declared as "unsigned
+             long" up to AIX 5.2, but are "unsigned int" since 5.3.
+             Use temporaries to work around this problem.  Also, add an
+             assert here to make sure we fail if the system header files
+             use "unsigned long", and the size of that type is not what
+             the headers expect.  */
+          uint32_t tmp_iar, tmp_msr, tmp_cr, tmp_lr, tmp_ctr, tmp_xer,
+                   tmp_fpscr;
+
+          gdb_assert (sizeof (sprs32.pt_iar) == 4);
+
+          /* Pre-fetch: some registers won't be in the cache.  */
+          ptrace32 (PTT_READ_SPRS, tid, (long long) &sprs32, 0, NULL);
+
+          fill_sprs32 (regcache, &tmp_iar, &tmp_msr, &tmp_cr, &tmp_lr,
+                       &tmp_ctr, &tmp_xer, &tmp_fpscr);
+
+          sprs32.pt_iar = tmp_iar;
+          sprs32.pt_msr = tmp_msr;
+          sprs32.pt_cr = tmp_cr;
+          sprs32.pt_lr = tmp_lr;
+          sprs32.pt_ctr = tmp_ctr;
+          sprs32.pt_xer = tmp_xer;
+          sprs32.pt_fpscr = tmp_fpscr;
+
+          if (tdep->ppc_mq_regnum >= 0)
+            if (REG_VALID == regcache_register_status (regcache,
+                                                       tdep->ppc_mq_regnum))
+              regcache_raw_collect (regcache, tdep->ppc_mq_regnum,
+                                    &sprs32.pt_mq);
+
+          ptrace32 (PTT_WRITE_SPRS, tid, (long long) &sprs32, 0, NULL);
+        }
+    }
+}
+
+/* Store gdb's current view of the register set into the
+   thread/process specified by inferior_ptid.  */
+
+static void
+aix_thread_store_registers (struct target_ops *ops,
+                            struct regcache *regcache, int regno)
+{
+  struct thread_info *thread;
+  pthdb_tid_t tid;
+  struct target_ops *beneath = find_target_beneath (ops);
+
+  if (!PD_TID (inferior_ptid))
+    beneath->to_store_registers (beneath, regcache, regno);
+  else
+    {
+      thread = find_thread_ptid (inferior_ptid);
+      tid = thread->private->tid;
+
+      if (tid == PTHDB_INVALID_TID)
+        store_regs_user_thread (regcache, thread->private->pdtid);
+      else
+        store_regs_kernel_thread (regcache, regno, tid);
+    }
+}
+
+/* Attempt a transfer all LEN bytes starting at OFFSET between the
+   inferior's OBJECT:ANNEX space and GDB's READBUF/WRITEBUF buffer.
+   Return the number of bytes actually transferred.  */
+
+static LONGEST
+aix_thread_xfer_partial (struct target_ops *ops, enum target_object object,
+                         const char *annex, gdb_byte *readbuf,
+                         const gdb_byte *writebuf,
+                         ULONGEST offset, LONGEST len)
+{
+  struct cleanup *old_chain = save_inferior_ptid ();
+  LONGEST xfer;
+  struct target_ops *beneath = find_target_beneath (ops);
+
+  inferior_ptid = pid_to_ptid (PIDGET (inferior_ptid));
+  xfer = beneath->to_xfer_partial (beneath, object, annex,
+                                   readbuf, writebuf, offset, len);
+
+  do_cleanups (old_chain);
+  return xfer;
+}
+
+/* Clean up after the inferior exits.  */
+
+static void
+aix_thread_mourn_inferior (struct target_ops *ops)
+{
+  struct target_ops *beneath = find_target_beneath (ops);
+
+  pd_deactivate ();
+  beneath->to_mourn_inferior (beneath);
+}
+
+/* Return whether thread PID is still valid.  */
+
+static int
+aix_thread_thread_alive (struct target_ops *ops, ptid_t ptid)
+{
+  struct target_ops *beneath = find_target_beneath (ops);
+
+  if (!PD_TID (ptid))
+    return beneath->to_thread_alive (beneath, ptid);
+
+  /* We update the thread list every time the child stops, so all
+     valid threads should be in the thread list.  */
+  return in_thread_list (ptid);
+}
+
+/* Return a printable representation of composite PID for use in
+   "info threads" output.  */
+
+static char *
+aix_thread_pid_to_str (struct target_ops *ops, ptid_t ptid)
+{
+  static char *ret = NULL;
+  struct target_ops *beneath = find_target_beneath (ops);
+
+  if (!PD_TID (ptid))
+    return beneath->to_pid_to_str (beneath, ptid);
+
+  /* Free previous return value; a new one will be allocated by
+     xstrprintf().  */
+  xfree (ret);
+
+  ret = xstrprintf (_("Thread %ld"), ptid_get_tid (ptid));
+  return ret;
+}
+
+/* Return a printable representation of extra information about
+   THREAD, for use in "info threads" output.  */
+
+static char *
+aix_thread_extra_thread_info (struct thread_info *thread)
+{
+  struct ui_file *buf;
+  int status;
+  pthdb_pthread_t pdtid;
+  pthdb_tid_t tid;
+  pthdb_state_t state;
+  pthdb_suspendstate_t suspendstate;
+  pthdb_detachstate_t detachstate;
+  int cancelpend;
+  static char *ret = NULL;
+
+  if (!PD_TID (thread->ptid))
+    return NULL;
+
+  buf = mem_fileopen ();
+
+  pdtid = thread->private->pdtid;
+  tid = thread->private->tid;
+
+  if (tid != PTHDB_INVALID_TID)
+    /* i18n: Like "thread-identifier %d, [state] running, suspended" */
+    fprintf_unfiltered (buf, _("tid %d"), (int)tid);
+
+  status = pthdb_pthread_state (pd_session, pdtid, &state);
+  if (status != PTHDB_SUCCESS)
+    state = PST_NOTSUP;
+  fprintf_unfiltered (buf, ", %s", state2str (state));
+
+  status = pthdb_pthread_suspendstate (pd_session, pdtid,
+                                       &suspendstate);
+  if (status == PTHDB_SUCCESS && suspendstate == PSS_SUSPENDED)
+    /* i18n: Like "Thread-Id %d, [state] running, suspended" */
+    fprintf_unfiltered (buf, _(", suspended"));
+
+  status = pthdb_pthread_detachstate (pd_session, pdtid,
+                                      &detachstate);
+  if (status == PTHDB_SUCCESS && detachstate == PDS_DETACHED)
+    /* i18n: Like "Thread-Id %d, [state] running, detached" */
+    fprintf_unfiltered (buf, _(", detached"));
+
+  pthdb_pthread_cancelpend (pd_session, pdtid, &cancelpend);
+  if (status == PTHDB_SUCCESS && cancelpend)
+    /* i18n: Like "Thread-Id %d, [state] running, cancel pending" */
+    fprintf_unfiltered (buf, _(", cancel pending"));
+
+  ui_file_write (buf, "", 1);
+
+  xfree (ret);                  /* Free old buffer.  */
+
+  ret = ui_file_xstrdup (buf, NULL);
+  ui_file_delete (buf);
+
+  return ret;
+}
+
+static ptid_t
+aix_thread_get_ada_task_ptid (long lwp, long thread)
+{
+  return ptid_build (ptid_get_pid (inferior_ptid), 0, thread);
+}
+
+/* Initialize target aix_thread_ops.  */
+
+static void
+init_aix_thread_ops (void)
+{
+  aix_thread_ops.to_shortname = "aix-threads";
+  aix_thread_ops.to_longname = _("AIX pthread support");
+  aix_thread_ops.to_doc = _("AIX pthread support");
+
+  aix_thread_ops.to_attach = aix_thread_attach;
+  aix_thread_ops.to_detach = aix_thread_detach;
+  aix_thread_ops.to_resume = aix_thread_resume;
+  aix_thread_ops.to_wait = aix_thread_wait;
+  aix_thread_ops.to_fetch_registers = aix_thread_fetch_registers;
+  aix_thread_ops.to_store_registers = aix_thread_store_registers;
+  aix_thread_ops.to_xfer_partial = aix_thread_xfer_partial;
+  /* No need for aix_thread_ops.to_create_inferior, because we activate thread
+     debugging when the inferior reaches pd_brk_addr.  */
+  aix_thread_ops.to_mourn_inferior = aix_thread_mourn_inferior;
+  aix_thread_ops.to_thread_alive = aix_thread_thread_alive;
+  aix_thread_ops.to_pid_to_str = aix_thread_pid_to_str;
+  aix_thread_ops.to_extra_thread_info = aix_thread_extra_thread_info;
+  aix_thread_ops.to_get_ada_task_ptid = aix_thread_get_ada_task_ptid;
+  aix_thread_ops.to_stratum = thread_stratum;
+  aix_thread_ops.to_magic = OPS_MAGIC;
+}
+
+/* Module startup initialization function, automagically called by
+   init.c.  */
+
+void _initialize_aix_thread (void);
+
+void
+_initialize_aix_thread (void)
+{
+  init_aix_thread_ops ();
+  add_target (&aix_thread_ops);
+
+  /* Notice when object files get loaded and unloaded.  */
+  observer_attach_new_objfile (new_objfile);
+
+  add_setshow_boolean_cmd ("aix-thread", class_maintenance, &debug_aix_thread,
+                           _("Set debugging of AIX thread module."),
+                           _("Show debugging of AIX thread module."),
+                           _("Enables debugging output (used to debug GDB)."),
+                           NULL, NULL,
+                           /* FIXME: i18n: Debugging of AIX thread
+                              module is \"%d\".  */
+                           &setdebuglist, &showdebuglist);
+}
