ada-exp.y: Synchronize with current ACT sources.

ada-lang.c: Ditto.
ada-lang.h: Ditto.
ada-lex.l: Ditto.
ada-tasks.c: Ditto.
ada-typeprint.c: Ditto.
ada-valprint.c: Ditto.

1 files changed, 1087 insertions, 422 deletions

diff --git a/gdb/ada-tasks.c b/gdb/ada-tasks.c
index f753712..2592617 100644
--- a/gdb/ada-tasks.c
+++ b/gdb/ada-tasks.c
@@ -1,10 +1,10 @@
-/* file ada-tasks.c: Ada tasking control for GDB
-   Copyright 1997 Free Software Foundation, Inc.
-   Contributed by Ada Core Technologies, Inc
-.
+/* File ada-tasks.c: Ada tasking control for GDB
+   Copyright 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
+   Free Software Foundation, Inc.
+   Contributed by Ada Core Technologies, Inc.
+
    This file is part of GDB.
 
-   [$Id$]
    Authors: Roch-Alexandre Nomine Beguin, Arnaud Charlet <charlet@gnat.com>
 
    This program is free software; you can redistribute it and/or modify
@@ -15,6 +15,7 @@
 */
 
 #include <ctype.h>
+#include <gdb_string.h>
 #include "defs.h"
 #include "command.h"
 #include "value.h"
@@ -22,94 +23,294 @@
 #include "inferior.h"
 #include "symtab.h"
 #include "target.h"
-#include "regcache.h"
 #include "gdbcore.h"
+#include "gdbthread.h"
+#include "regcache.h"       /* for registers_changed */
 
-#if (defined(__alpha__) && defined(__osf__) && !defined(__alpha_vxworks))
+#if defined (__fsu__) || defined (HAVE_SPYTHREAD) \
+    || (defined(__alpha__) && defined(__osf__) && !defined(__alpha_vxworks))
 #include <sys/procfs.h>
 #endif
 
-#if (defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET))
+#if defined (__fsu__) || defined (HAVE_SPYTHREAD) \
+    || (defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET))
 #include "gregset.h"
 #endif
 
-#include "ada-lang.h"
+#ifdef I386_GNULINUX_TARGET
+#include "gdb_thread_db.h"
+#endif
 
-/* FIXME: move all this conditional compilation in description
-   files or in configure.in */
+#if defined (HAVE_SPYTHREAD)
+#include "irix6-spyThread.h"
+#endif
 
-#if defined (VXWORKS_TARGET)
-#define THREAD_TO_PID(tid,lwpid) (tid)
+#include "ada-lang.h"
+#include "observer.h"
 
-#elif defined (linux)
-#define THREAD_TO_PID(tid,lwpid) (0)
+enum task_states
+{
+  Unactivated,
+  Runnable,
+  Terminated,
+  Activator_Sleep,
+  Acceptor_Sleep,
+  Entry_Caller_Sleep,
+  Async_Select_Sleep,
+  Delay_Sleep,
+  Master_Completion_Sleep,
+  Master_Phase_2_Sleep
+};
 
-#elif (defined (sun) && defined (__SVR4))
-#define THREAD_TO_PID thread_to_pid
+struct task_control_block
+{
+  char state;
+  CORE_ADDR parent;
+  int priority;
+  char image [32];
+  int image_len;    /* This field is not always present in the ATCB.  */
+  CORE_ADDR call;
+  CORE_ADDR thread;
+  CORE_ADDR lwp;    /* This field is not always present in the ATCB.  */
+};
 
-#elif defined (sgi) || defined (__WIN32__) || defined (hpux)
-#define THREAD_TO_PID(tid,lwpid) ((int)lwpid)
+/* The index of certain important fields in the Ada Task Control Block
+   record and sub-records.  */
 
+struct tcb_fieldnos
+{
+  /* Fields in record Ada_Task_Control_Block.  */
+  int common;
+
+  /* Fields in record Common_ATCB.  */
+  int state;
+  int parent;
+  int priority;
+  int image;
+  int image_len;     /* This field may be missing.  */
+  int call;
+  int ll;
+
+  /* Fields in Task_Primitives.Private_Data.  */
+  int ll_thread;
+  int ll_lwp;        /* This field may be missing.  */
+};
+
+#if defined (linux)
+#define TASK_LWP(atcb) 0L
 #else
-#define THREAD_TO_PID(tid,lwpid) (0)
+#define TASK_LWP(atcb) extract_unsigned_integer (&(atcb).lwp, sizeof ((atcb).lwp))
 #endif
 
+struct task_ptid
+{
+  int pid;                      /* The Process id */
+  long lwp;                     /* The Light Weight Process id */
+  long tid;                     /* The Thread id */
+};
+typedef struct task_ptid task_ptid_t;
+
+struct task_entry
+{
+  CORE_ADDR task_id;
+  struct task_control_block atcb;
+  int task_num;
+  int known_tasks_index;
+  struct task_entry *next_task;
+  task_ptid_t task_ptid;
+  int stack_per;
+};
+
+/* FIXME: move all this conditional compilation in description
+   files or in configure.in */
+
 #if defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET)
+#define SPECIAL_THREAD_SUPPORT_ACTIVE() thread_support
+#define SAVE_TASK_REGISTERS(task) \
+  do { fill_gregset (&gregset_saved, -1); \
+       fill_fpregset (&fpregset_saved, -1); \
+  } while (0)
+#define RESTORE_TASK_REGISTERS(task) \
+  do { supply_gregset (&gregset_saved); \
+       supply_fpregset (&fpregset_saved); \
+  } while (0)
+
 #define THREAD_FETCH_REGISTERS dec_thread_fetch_registers
-#define GET_CURRENT_THREAD dec_thread_get_current_thread
+#define GET_CURRENT_THREAD(PTID) dec_thread_get_current_thread ()
+extern unsigned long dec_thread_get_current_thread (void);
 extern int dec_thread_get_registers (gdb_gregset_t *, gdb_fpregset_t *);
+extern int dec_thread_fetch_registers (void);
 #endif
 
-#if defined (_AIX)
-#define THREAD_FETCH_REGISTERS aix_thread_fetch_registers
-#define GET_CURRENT_THREAD aix_thread_get_current_thread
+#ifdef __fsu__
+#define SPECIAL_THREAD_SUPPORT_ACTIVE() \
+   (thread_support && pthread_kern_addr != 0)
+#define SAVE_TASK_REGISTERS(task) \
+  do { \
+    if (pthread_kern_addr != 0) \
+      { \
+        fill_gregset (&gregset_saved, -1); \
+        fill_fpregset (&fpregset_saved, -1); \
+      } \
+  } while (0)
+#define RESTORE_TASK_REGISTERS(task) \
+  do { \
+    if (pthread_kern_addr != 0) \
+      { \
+        supply_gregset (&gregset_saved); \
+        supply_fpregset (&fpregset_saved); \
+      } \
+  } while (0)
+
+extern int fsu_thread_fetch_registers (void);
+extern unsigned long fsu_thread_get_current_thread (void);
+static int fsu_or_linux_thread_fetch_registers (void);
+static long fsu_or_linux_thread_get_current_thread (ptid_t);
+#define THREAD_FETCH_REGISTERS fsu_or_linux_thread_fetch_registers
+#define GET_CURRENT_THREAD(PTID) fsu_or_linux_thread_get_current_thread (PTID)
+#define PTHREAD_KERN "pthread_kern"
+#endif
+
+#ifdef I386_GNULINUX_TARGET
+extern td_thrinfo_t thread_db_pid_to_thread_info (int pid);
+extern int thread_db_tid_to_pid (void *tid);
 #endif
 
 #if defined(VXWORKS_TARGET)
-#define GET_CURRENT_THREAD() ((void*)inferior_pid)
+#define GET_CURRENT_THREAD(PTID) (unsigned long) ptid_get_pid (PTID)
 #define THREAD_FETCH_REGISTERS() (-1)
 
-#elif defined (sun) && defined (__SVR4)
-#define GET_CURRENT_THREAD solaris_thread_get_current_thread
+#elif defined (__WIN32__) || defined (__CYGWIN__) || defined (hpux)
+#define GET_CURRENT_THREAD(PTID) ptid_get_pid (PTID)
 #define THREAD_FETCH_REGISTERS() (-1)
-extern void *GET_CURRENT_THREAD ();
+#endif
 
-#elif defined (_AIX) || (defined(__alpha__) && defined(__osf__))
-extern void *GET_CURRENT_THREAD ();
+#if defined (HAVE_SPYTHREAD)
+#define GET_CURRENT_THREAD(PTID) (unsigned long) TIDGET (PTID)
+#endif
 
-#elif defined (__WIN32__) || defined (hpux)
-#define GET_CURRENT_THREAD() (inferior_pid)
-#define THREAD_FETCH_REGISTERS() (-1)
+#if !defined(GET_CURRENT_THREAD)
+#define GET_CURRENT_THREAD(PTID) (unsigned long) ptid_get_tid (PTID)
+#endif
 
-#else
-#define GET_CURRENT_THREAD() (NULL)
-#define THREAD_FETCH_REGISTERS() (-1)
+#if !defined(THREAD_FETCH_REGISTERS)
+#define THREAD_FETCH_REGISTERS() (target_fetch_registers (-1), 0)
+#endif
+
+#if !defined(SAVE_TASK_REGISTERS)
+#define SAVE_TASK_REGISTERS(task)
+#define RESTORE_TASK_REGISTERS(task)
+#endif
+
+#if !defined(SPECIAL_THREAD_SUPPORT_ACTIVE)
+#define SPECIAL_THREAD_SUPPORT_ACTIVE() 0
 #endif
 
 #define KNOWN_TASKS_NAME "system__tasking__debug__known_tasks"
 
-#define READ_MEMORY(addr, var) read_memory (addr, (char*) &var, sizeof (var))
-/* external declarations */
+#define READ_MEMORY(addr, var) read_memory (addr, (char *) &var, sizeof (var))
+
+/* If defined to 1, means that the thread ptids maintained by core GDB
+   follow this format : first field (pid) contains the tid
+                       second field (lwp) contains 0
+                       third field (tid) contains 0 */
+#ifndef THREAD_PTID_CONTAINS_TID_NULL_NULL
+#define THREAD_PTID_CONTAINS_TID_NULL_NULL (0)
+#endif
+
+/* If defined to 1, means that the thread ptids maintained by core GDB
+   follow this format: first field (pid) contains the LWP id
+                       second field (lwp) contains 0
+                       third field (tid) contains 0 */
+#ifndef THREAD_PTID_CONTAINS_LWP_NULL_NULL
+#define THREAD_PTID_CONTAINS_LWP_NULL_NULL (0)
+#endif
+
+/* If defined to 1, means that the thread ptids maintained by core GDB
+   follow this format: first field (pid) contains the PID
+                       second field (lwp) contains 0
+                       third field (tid) contains the TID */
+#ifndef THREAD_PTID_CONTAINS_PID_NULL_TID
+#define THREAD_PTID_CONTAINS_PID_NULL_TID (0)
+#endif
+
+/* If defined to 1, means that the thread ptids maintained by core GDB
+   follow this format: first field (pid) contains the PID
+                       second field (lwp) contains the TID
+                       third field (tid) contains the 0 */
+
+#ifndef THREAD_PTID_CONTAINS_PID_TID_NULL
+#define THREAD_PTID_CONTAINS_PID_TID_NULL (0)
+#endif
+
+/* If defined to 1, means that the thread id is not stored in the tid
+   field of the task_ptid, but rather in the lwp field.  */
+#ifndef ADA_THREAD_ID_IN_LWP
+#define ADA_THREAD_ID_IN_LWP (0)
+#endif
+
+static int task_ptid_get_pid (task_ptid_t task_ptid);
+static long task_ptid_get_lwp (task_ptid_t task_ptid);
+static long task_ptid_get_tid (task_ptid_t task_ptid);
+static task_ptid_t task_ptid_build (int pid, long lwp, long tid);
+static ptid_t task_ptid_get_ptid (task_ptid_t task_ptid);
+static long task_ptid_get_thread_id (task_ptid_t task_ptid);
+
+static int task_is_alive (enum task_states state);
+static CORE_ADDR get_self_id (ptid_t);
+static int get_entry_number (CORE_ADDR);
+static void get_tcb_types_info (struct type **atcb_type,
+                                struct type **atcb_common_type,
+                                struct type **atcb_ll_type,
+                                struct tcb_fieldnos *atcb_fieldnos);
+static void get_tcb_call_type_info (struct type **atcb_call_type,
+                                    int *atcb_call_self_fieldno);
+static CORE_ADDR get_known_tasks_addr (void);
+static int read_known_tasks_array (void);
+static int build_task_list (void);
+static void value_as_string (char *dest, struct value *val, int length);
+static struct task_control_block read_atcb (CORE_ADDR atcb_addr);
+static CORE_ADDR read_caller (const CORE_ADDR call);
+static void display_current_task_id (void);
+static void task_command_1 (char *tidstr, int from_tty);
+
+/* Ada-tasks observers.  */
+
+static void normal_stop_notification (void);
+static void ada_tasks_attach_observers (void);
 
 /* Global visible variables */
 
-struct task_entry *task_list = NULL;
 int ada__tasks_check_symbol_table = 1;
-void *pthread_kern_addr = NULL;
+CORE_ADDR pthread_kern_addr = 0;
+
+/* Local global variables.  */
+static struct task_entry *task_list = NULL;
 
-#if (defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET))
+/* When non-zero, this flag indicates that the current task_list
+   is obsolete, and should be recomputed before it is accessed.  */
+static int stale_task_list_p = 1;
+
+#if defined (__fsu__) || (defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET))
 gdb_gregset_t gregset_saved;
 gdb_fpregset_t fpregset_saved;
 #endif
 
 /* The maximum number of tasks known to the Ada runtime */
-const int MAX_NUMBER_OF_KNOWN_TASKS = 1000;
+static const int MAX_NUMBER_OF_KNOWN_TASKS = 1000;
+
+/* the current task, as seen by the user. Modified everytime the user
+   does a task switch.  */
+static int current_task = -1;
 
-/* the current task */
-int current_task = -1, current_task_id = -1, current_task_index;
-void *current_thread, *current_lwp;
+unsigned long current_thread;
 
-char *ada_task_states[] = {
+/* The task where the debugger stopped, giving control back to the user.
+   Not affected by task switching. Used to restore the registers before
+   continuing the inferior.  */
+int current_task_id = -1;
+
+static char *task_states[] = {
   "Unactivated",
   "Runnable",
   "Terminated",
@@ -129,7 +330,7 @@ char *ada_task_states[] = {
 
 /* Global internal types */
 
-static char *ada_long_task_states[] = {
+static char *long_task_states[] = {
   "Unactivated",
   "Runnable",
   "Terminated",
@@ -150,11 +351,34 @@ static char *ada_long_task_states[] = {
 /* Global internal variables */
 
 static int highest_task_num = 0;
-int thread_support = 0;		/* 1 if the thread library in use is supported */
-static int gdbtk_task_initialization = 0;
+static int thread_support = 0;  /* 1 if the thread library in use is
+                                   supported. FIXME: Not reinitialized
+                                   properly when program reloaded.
+                                 */
+#ifdef __fsu__
+static int
+fsu_or_linux_thread_fetch_registers (void)
+{
+  if (pthread_kern_addr != 0)
+    return fsu_thread_fetch_registers ();
+
+  target_fetch_registers (-1);
+  return 0L;
+}
+
+static long
+fsu_or_linux_thread_get_current_thread (ptid_t ptid)
+{
+  if (pthread_kern_addr != 0)
+    return fsu_thread_get_current_thread ();
+
+  return ptid_get_tid (ptid);
+}
+
+#endif /* __fsu__ */
 
 static int
-add_task_entry (void *p_task_id, int index)
+add_task_entry (CORE_ADDR p_task_id, int index)
 {
   struct task_entry *new_task_entry = NULL;
   struct task_entry *pt;
@@ -163,13 +387,18 @@ add_task_entry (void *p_task_id, int index)
   new_task_entry = xmalloc (sizeof (struct task_entry));
   new_task_entry->task_num = highest_task_num;
   new_task_entry->task_id = p_task_id;
+  new_task_entry->atcb = read_atcb (p_task_id);
   new_task_entry->known_tasks_index = index;
+  new_task_entry->task_ptid =
+    task_ptid_build (ptid_get_pid (inferior_ptid), /* ? */
+                                   TASK_LWP (new_task_entry->atcb),
+                                   new_task_entry->atcb.thread);
   new_task_entry->next_task = NULL;
   pt = task_list;
   if (pt)
     {
       while (pt->next_task)
-	pt = pt->next_task;
+        pt = pt->next_task;
       pt->next_task = new_task_entry;
       pt->stack_per = 0;
     }
@@ -178,8 +407,8 @@ add_task_entry (void *p_task_id, int index)
   return new_task_entry->task_num;
 }
 
-int
-get_entry_number (void *p_task_id)
+static int
+get_entry_number (CORE_ADDR p_task_id)
 {
   struct task_entry *pt;
 
@@ -187,22 +416,22 @@ get_entry_number (void *p_task_id)
   while (pt != NULL)
     {
       if (pt->task_id == p_task_id)
-	return pt->task_num;
+        return pt->task_num;
       pt = pt->next_task;
     }
   return 0;
 }
 
 static struct task_entry *
-get_thread_entry_vptr (void *thread)
+get_thread_entry_vptr (long thread)
 {
   struct task_entry *pt;
 
   pt = task_list;
   while (pt != NULL)
     {
-      if (pt->thread == thread)
-	return pt;
+      if (task_ptid_get_thread_id (pt->task_ptid) == thread)
+        return pt;
       pt = pt->next_task;
     }
   return 0;
@@ -217,7 +446,7 @@ get_entry_vptr (int p_task_num)
   while (pt)
     {
       if (pt->task_num == p_task_num)
-	return pt;
+        return pt;
       pt = pt->next_task;
     }
   return NULL;
@@ -228,6 +457,8 @@ init_task_list (void)
 {
   struct task_entry *pt, *old_pt;
 
+  target_find_new_threads ();
+
   pt = task_list;
   while (pt)
     {
@@ -245,64 +476,592 @@ valid_task_id (int task)
   return get_entry_vptr (task) != NULL;
 }
 
-void *
-get_self_id (void)
+/* Return the pid of a given task ptid.  */
+
+static int
+task_ptid_get_pid (task_ptid_t task_ptid)
 {
-  struct value *val;
-  void *self_id;
-  int result;
+  return task_ptid.pid;
+}
+
+/* Return the lwp of a given task ptid.  */
+
+static long
+task_ptid_get_lwp (task_ptid_t task_ptid)
+{
+  return task_ptid.lwp;
+}
+
+/* Return the tid of a given task ptid.  */
+
+static long
+task_ptid_get_tid (task_ptid_t task_ptid)
+{
+  return task_ptid.tid;
+}
+
+/* Build a task ptid from the associated pid, lwp, and tid.  */
+
+static task_ptid_t
+task_ptid_build (int pid, long lwp, long tid)
+{
+  task_ptid_t task_ptid;
+
+  task_ptid.pid = pid;
+  task_ptid.lwp = lwp;
+  task_ptid.tid = tid;
+  return task_ptid;
+}
+
+/* Translate a task ptid into a ptid (the ptid maintained by core GDB).
+
+   On most platforms, they are equivalent, and this function can be
+   regarded as the identity. However, there are other platforms where
+   the task ptid and the ptid are not equivalent. For instance, the task
+   LWP value is sometimes stored by GDB-core as a pid! This translation
+   therefore becomes necessary before invoking the GDB thread services.  */
+
+static ptid_t
+task_ptid_get_ptid (task_ptid_t task_ptid)
+{
+  ptid_t ptid;
+
+  if (THREAD_PTID_CONTAINS_TID_NULL_NULL)
+    ptid = ptid_build (task_ptid_get_tid (task_ptid), 0, 0);
+  else if (THREAD_PTID_CONTAINS_LWP_NULL_NULL)
+    ptid = ptid_build (task_ptid_get_lwp (task_ptid), 0, 0);
+  else if (THREAD_PTID_CONTAINS_PID_NULL_TID)
+    ptid = ptid_build (task_ptid_get_pid (task_ptid),
+                       0, task_ptid_get_tid (task_ptid));
+  else if (THREAD_PTID_CONTAINS_PID_TID_NULL)
+    ptid = ptid_build (task_ptid_get_pid (task_ptid),
+                       task_ptid_get_tid (task_ptid), 0);
+  else
+    ptid = ptid_build (task_ptid_get_pid (task_ptid),
+                       task_ptid_get_lwp (task_ptid),
+                       task_ptid_get_tid (task_ptid));
+
+  return ptid;
+}
+
+/* Extract and return the thread_id for the given TASK_PTID.  */
+
+static long
+task_ptid_get_thread_id (task_ptid_t task_ptid)
+{
+  /* On most platforms, the thread_id is stored in task_ptid.tid.
+     Unfortunately, some other platforms store it as the task_ptid.lwp...  */
+
+  if (ADA_THREAD_ID_IN_LWP)
+    return task_ptid_get_lwp (task_ptid);
+  else
+    return task_ptid_get_tid (task_ptid);
+}
+
+/* Return non-zero iff the task STATE corresponds to a non-terminated
+   task state.  */
+
+static int
+task_is_alive (enum task_states state)
+{
+  return (state != Terminated);
+}
+
+static CORE_ADDR
+get_self_id (ptid_t ptid)
+{
+#ifdef GNAT_GDB
   struct task_entry *ent;
-  extern int do_not_insert_breakpoints;
 
 #if !((defined(sun) && defined(__SVR4)) || defined(VXWORKS_TARGET) || defined(__WIN32__))
   if (thread_support)
 #endif
     {
-      ent = get_thread_entry_vptr (GET_CURRENT_THREAD ());
+      ent = get_thread_entry_vptr (GET_CURRENT_THREAD (ptid));
       return ent ? ent->task_id : 0;
     }
+#endif
 
   /* FIXME: calling a function in the inferior with a multithreaded application
-     is not reliable, so return NULL if there is no safe way to get the current
-     task */
-  return NULL;
+     is not reliable, so return a null address if there is no safe way to
+     get the current task */
+  return 0;
 }
 
 int
-get_current_task (void)
+ada_get_current_task (ptid_t ptid)
 {
   int result;
 
-  /* FIXME: language_ada should be defined in defs.h */
-  /*  if (current_language->la_language != language_ada) return -1; */
+  if (current_language->la_language != language_ada)
+    return -1;
 
-  result = get_entry_number (get_self_id ());
+  result = get_entry_number (get_self_id (ptid));
 
   /* return -1 if not found */
   return result == 0 ? -1 : result;
 }
 
+/* Get from the debugging information the type description of all types
+   related to the Ada Task Control Block that will be needed in order to
+   read the list of known tasks in the Ada runtime.  Also return the
+   associated ATCB_FIELDNOS.
+
+   Error handling:  Any data missing from the debugging info will cause
+   an error to be raised, and none of the return values to be set.
+   Users of this function can depend on the fact that all or none of the
+   return values will be set.  */
+
+static void
+get_tcb_types_info (struct type **atcb_type,
+                    struct type **atcb_common_type,
+                    struct type **atcb_ll_type,
+                    struct tcb_fieldnos *atcb_fieldnos)
+{
+  struct type *type;
+  struct type *common_type;
+  struct type *ll_type;
+  struct tcb_fieldnos fieldnos;
+
+#ifndef ADA_RETAIN_DOTS
+  const char *atcb_name = "system__tasking__ada_task_control_block___XVE";
+  const char *common_atcb_name = "system__tasking__common_atcb";
+  const char *private_data_name = "system__task_primitives__private_data";
+#else
+  const char *atcb_name = "system.tasking.ada_task_control_block___XVE";
+  const char *common_atcb_name = "system.tasking.common_atcb";
+  const char *private_data_name = "system.task_primitives.private_data";
+#endif
+
+  const struct symbol *atcb_sym =
+    lookup_symbol (atcb_name, NULL, VAR_DOMAIN, NULL, NULL);
+  const struct symbol *common_atcb_sym =
+    lookup_symbol (common_atcb_name, NULL, VAR_DOMAIN, NULL, NULL);
+  const struct symbol *private_data_sym =
+    lookup_symbol (private_data_name, NULL, VAR_DOMAIN, NULL, NULL);
+
+  if (atcb_sym == NULL || atcb_sym->type == NULL)
+    error ("Can not find Ada_Task_Control_Block type. Aborting");
+  if (common_atcb_sym == NULL || common_atcb_sym->type == NULL)
+    error ("Can not find Common_ATCB type. Aborting");
+  if (private_data_sym == NULL || private_data_sym->type == NULL)
+    error ("Can not find Private_Data type. Aborting");
+
+  /* Get a static representation of the type record Ada_Task_Control_Block.  */
+  type = atcb_sym->type;
+  type = ada_template_to_fixed_record_type_1 (type, NULL, 0, NULL, 0);
+
+  /* Get the type for Ada_Task_Control_Block.Common.  */
+  common_type = common_atcb_sym->type;
+
+  /* Get the type for Ada_Task_Control_Bloc.Common.Call.LL.  */
+  ll_type = private_data_sym->type;
+
+  /* Get the field indices.  */
+  fieldnos.common = ada_get_field_index (type, "common", 0);
+  fieldnos.state = ada_get_field_index (common_type, "state", 0);
+  fieldnos.parent = ada_get_field_index (common_type, "parent", 0);
+  fieldnos.priority = ada_get_field_index (common_type, "base_priority", 0);
+  fieldnos.image = ada_get_field_index (common_type, "task_image", 0);
+  fieldnos.image_len = ada_get_field_index (common_type, "task_image_len", 1);
+  fieldnos.call = ada_get_field_index (common_type, "call", 0);
+  fieldnos.ll = ada_get_field_index (common_type, "ll", 0);
+  fieldnos.ll_thread = ada_get_field_index (ll_type, "thread", 0);
+  fieldnos.ll_lwp = ada_get_field_index (ll_type, "lwp", 1);
+
+  /* On certain platforms such as x86-windows, the "lwp" field has been
+     named "thread_id".  This field will likely be renamed in the future,
+     but we need to support both possibilities to avoid an unnecessary
+     dependency on a recent compiler.  We therefore try locating the
+     "thread_id" field in place of the "lwp" field if we did not find
+     the latter.  */
+  if (fieldnos.ll_lwp < 0)
+    fieldnos.ll_lwp = ada_get_field_index (ll_type, "thread_id", 1);
+
+  /* Set all the out parameters all at once, now that we are certain
+     that there are no potential error() anymore.  */
+  *atcb_type = type;
+  *atcb_common_type = common_type;
+  *atcb_ll_type = ll_type;
+  *atcb_fieldnos = fieldnos;
+}
+
+/* Get from the debugging information the type description of the
+   record type Entry_Call_Record (this is the type of the field
+   Call.all in the Common_ATCB record type). Also return the index
+   of the field "Self" in Entry_Call_Record.
+
+   Error handling:  Any data missing from the debugging info will cause
+   an error to be raised, and none of the return values to be set.
+   Users of this function can depend on the fact that all or none of the
+   return values will be set.  */
+
+static void
+get_tcb_call_type_info (struct type **atcb_call_type,
+                        int *atcb_call_self_fieldno)
+{
+  struct type *call_type;
+  int call_self_fieldno;
+
+#ifndef ADA_RETAIN_DOTS
+  const char *entry_call_record_name = "system__tasking__entry_call_record";
+#else
+  const char *entry_call_record_name = "system.tasking.entry_call_record";
+#endif
+
+  const struct symbol *entry_call_record_sym =
+    lookup_symbol (entry_call_record_name, NULL, VAR_DOMAIN, NULL, NULL);
+
+  if (entry_call_record_sym == NULL || entry_call_record_sym->type == NULL)
+    error ("Can not find Entry_Call_Record type. Aborting");
+
+  call_type = entry_call_record_sym->type;
+  call_self_fieldno = ada_get_field_index (call_type, "self", 0);
+
+  /* Set all the out parameters all at once, now that we are certain
+     that there are no potential error() anymore.  */
+  *atcb_call_type = call_type;
+  *atcb_call_self_fieldno = call_self_fieldno;
+}
+
+/* Return the address of the Known_Tasks array maintained in
+   the Ada Runtime.  Return NULL if the array could not be found,
+   meaning that the inferior program probably does not use tasking.
+
+   In order to provide a fast response time, this function caches
+   the Known_Tasks array address after the lookup during the first
+   call. Subsequent calls will simply return this cached address.  */
+
+static CORE_ADDR
+get_known_tasks_addr (void)
+{
+  static CORE_ADDR known_tasks_addr = 0;
+
+  if (ada__tasks_check_symbol_table)
+    {
+      struct symbol *sym;
+      struct minimal_symbol *msym;
+
+      thread_support = 0;
+#if (defined(__alpha__) && defined(__osf__) & !defined(VXWORKS_TARGET)) \
+    || defined (_AIX) || defined (__CYGWIN__)
+      thread_support = 1;
+#elif defined (__fsu__)
+      msym = lookup_minimal_symbol (PTHREAD_KERN, NULL, NULL);
+      if (msym != NULL)
+        {
+          pthread_kern_addr = SYMBOL_VALUE_ADDRESS (msym);
+          thread_support = 1;
+        }
+#elif defined (HAVE_SPYTHREAD)
+      thread_support = libspy_enabled;
+#endif
+
+#ifdef I386_GNULINUX_TARGET
+      /* We support threads via the Linux Threads...  */
+      thread_support = 1;
+#endif
+
+      msym = lookup_minimal_symbol (KNOWN_TASKS_NAME, NULL, NULL);
+      if (msym != NULL)
+        known_tasks_addr = SYMBOL_VALUE_ADDRESS (msym);
+      else
+#ifndef VXWORKS_TARGET
+        return 0;
+#else
+        {
+          if (target_lookup_symbol (KNOWN_TASKS_NAME, &known_tasks_addr) != 0)
+            return 0;
+        }
+#endif
+
+      /* FIXME: brobecker 2003-03-05: Here would be a much better place
+         to attach the ada-tasks observers, instead of doing this
+         unconditionaly in _initialize_tasks. This would avoid an
+         unecessary notification when the inferior does not use tasking
+         or as long as the user does not use the ada-tasks commands.
+         Unfortunately, this is not possible for the moment: the current
+         code resets ada__tasks_check_symbol_table back to 1 whenever
+         symbols for a new program are being loaded. If we place the
+         observers intialization here, we will end up adding new observers
+         everytime we do the check for Ada tasking-related symbols
+         above. This would currently have benign effects, but is still
+         undesirable. The cleanest approach is probably to create a new
+         observer to notify us when the user is debugging a new program.
+         We would then reset ada__tasks_check_symbol_table back to 1
+         during the notification, but also detach all observers.
+         BTW: observers are probably not reentrant, so detaching during
+         a notification may not be the safest thing to do... Sigh...
+         But creating the new observer would be a good idea in any case,
+         since this allow us to make ada__tasks_check_symbol_table
+         static, which is a good bonus.  */
+      ada__tasks_check_symbol_table = 0;
+    }
+
+  return known_tasks_addr;
+}
+
+/* Read the Known_Tasks array from the inferior memory, and store
+   it in task_list.  Return non-zero upon success.  */
+
+static int
+read_known_tasks_array (void)
+{
+  const int target_ptr_byte = TARGET_PTR_BIT / TARGET_CHAR_BIT;
+  const int temp_tasks_size = target_ptr_byte * MAX_NUMBER_OF_KNOWN_TASKS;
+  const CORE_ADDR known_tasks_addr = get_known_tasks_addr ();
+  char *temp_tasks = (char *) alloca (temp_tasks_size);
+  CORE_ADDR temp_task;
+  int i;
+
+  /* Step 1: Clear the current list, if any.  */
+  init_task_list ();
+
+  /* If the application does not use task, then no more needs to be done.
+     It is important to have the task list cleared (see above) before we
+     return, as we don't want a stale task list to be used...  This can
+     happen for instance when debugging a non-multitasking program after
+     having debugged a multitasking one.  */
+  if (known_tasks_addr == 0)
+    return 0;
+
+  /* Step 2: Build a new list by reading the ATCBs from the Known_Tasks
+     array in the Ada runtime.  */
+  read_memory (known_tasks_addr, temp_tasks, temp_tasks_size);
+  for (i = 0; i < MAX_NUMBER_OF_KNOWN_TASKS; i++)
+    {
+      temp_task = extract_typed_address (temp_tasks + i * target_ptr_byte,
+					 builtin_type_void_data_ptr);
+
+      if (temp_task != 0)
+        {
+          if (get_entry_number (temp_task) == 0)
+            add_task_entry (temp_task, i);
+        }
+    }
+
+  /* Step 3: Unset stale_task_list_p, to avoid re-reading the Known_Tasks
+     array unless needed.  Then report a success.  */
+  stale_task_list_p = 0;
+  return 1;
+}
+
+/* Builds the task_list by reading the Known_Tasks array from
+   the inferior.  Prints an appropriate message and returns non-zero
+   if it failed to build this list.  */
+
+static int
+build_task_list (void)
+{
+  if (!target_has_stack)
+    error ("No stack");
+
+  if (stale_task_list_p)
+    read_known_tasks_array ();
+
+  if (task_list == NULL)
+    {
+      printf_filtered ("Your application does not use any Ada task.\n");
+      return 0;
+    }
+
+  return 1;
+}
+
+/* Extract the contents of the value as a string whose length is LENGTH,
+   and store the result in DEST.  */
+
+static void
+value_as_string (char *dest, struct value *val, int length)
+{
+  memcpy (dest, VALUE_CONTENTS (val), length);
+}
+
+/* Extract the string image from the fat string corresponding to VAL,
+   and store it in DEST. The length of the string is stored in LEN.  If
+   the string length is greater than MAX_LEN, then truncate the result
+   to the first MAX_LEN characters of the fat string.  */
+
+static void
+read_fat_string_value (char *dest, int *len, struct value *val, int max_len)
+{
+  struct value *array_val;
+  struct value *bounds_val;
+
+  /* The following variables are made static to avoid recomputing them
+     each time this function is called.  */
+  static int initialize_fieldnos = 1;
+  static int array_fieldno;
+  static int bounds_fieldno;
+  static int upper_bound_fieldno;
+
+  /* Get the index of the fields that we will need to read in order
+     to extract the string from the fat string.  */
+  if (initialize_fieldnos)
+    {
+      struct type *type = VALUE_TYPE (val);
+      struct type *bounds_type;
+
+      array_fieldno = ada_get_field_index (type, "P_ARRAY", 0);
+      bounds_fieldno = ada_get_field_index (type, "P_BOUNDS", 0);
+
+      bounds_type = TYPE_FIELD_TYPE (type, bounds_fieldno);
+      if (TYPE_CODE (bounds_type) == TYPE_CODE_PTR)
+        bounds_type = TYPE_TARGET_TYPE (bounds_type);
+      if (TYPE_CODE (bounds_type) != TYPE_CODE_STRUCT)
+        error ("Unknown task name format. Aborting");
+      upper_bound_fieldno = ada_get_field_index (bounds_type, "UB0", 0);
+
+      initialize_fieldnos = 0;
+    }
+
+  /* Get the size of the task image by checking the value of the bounds.
+     The lower bound is always 1, so we only need to read the upper bound.  */
+  bounds_val = value_ind (value_field (val, bounds_fieldno));
+  *len = value_as_long (value_field (bounds_val, upper_bound_fieldno));
+
+  /* Make sure that we do not read more than max_len characters...  */
+  if (*len > max_len)
+    *len = max_len;
+
+  /* Extract LEN characters from the fat string.  */
+  array_val = value_ind (value_field (val, array_fieldno));
+  read_memory (VALUE_ADDRESS (array_val), dest, *len);
+}
+
+/* Read the ATCB stored at ATCB_ADDR from the inferior memory.  */
+
+static struct task_control_block
+read_atcb (CORE_ADDR atcb_addr)
+{
+  /* The type description for the ATCB record and subrecords, and
+     the associated tcb_fieldnos. For efficiency reasons, these are made
+     static so that we can compute them only once the first time and
+     reuse them later.  */
+  static struct type *atcb_type = NULL;
+  static struct type *atcb_common_type = NULL;
+  static struct type *atcb_ll_type = NULL;
+  static struct tcb_fieldnos fieldno;
+
+  struct task_control_block result;
+  struct value *tcb_value;
+  struct value *ll_value;
+
+  if (atcb_type == NULL)
+    get_tcb_types_info (&atcb_type, &atcb_common_type, &atcb_ll_type, &fieldno);
+
+  tcb_value = value_from_contents_and_address (atcb_type, NULL, atcb_addr);
+  tcb_value = value_field (tcb_value, fieldno.common);
+
+  result.state = value_as_long (value_field (tcb_value, fieldno.state));
+  result.parent = value_as_address (value_field (tcb_value, fieldno.parent));
+  result.priority = value_as_long (value_field (tcb_value, fieldno.priority));
+
+  /* Depending on the GNAT version used, the task image is either a fat
+     string, or a thin array of characters.  Older versions of GNAT used
+     to use fat strings, and therefore did not need an extra field in
+     the ATCB to store the string length. For efficiency reasons, newer
+     versions of GNAT replaced the fat string by a static buffer, but this
+     also required the addition of a new field named "Image_Len" containing
+     the length of the task name. The method used to extract the task name
+     is selected depending on the existence of this field.  */
+  if (fieldno.image_len == -1)
+    {
+      read_fat_string_value (result.image, &result.image_len,
+                             value_field (tcb_value, fieldno.image),
+                             sizeof (result.image));
+    }
+  else
+    {
+      value_as_string (result.image, value_field (tcb_value, fieldno.image),
+                       sizeof (result.image));
+      result.image_len =
+        value_as_long (value_field (tcb_value, fieldno.image_len));
+    }
+
+  result.call = value_as_address (value_field (tcb_value, fieldno.call));
+
+  ll_value = value_field (tcb_value, fieldno.ll);
+  result.thread = value_as_address (value_field (ll_value, fieldno.ll_thread));
+  if (fieldno.ll_lwp >= 0)
+    result.lwp = value_as_address (value_field (ll_value, fieldno.ll_lwp));
+  else
+    result.lwp = 0;
+
+  return result;
+}
+
+/*  Read the ID of the task with which a task is attempting a rendez-vous
+    from the address of its Entry_Call_Record in the Ada TCB.
+    If the address of the Entry_Call_Record is null, then return null.  */
+
+static CORE_ADDR
+read_caller (const CORE_ADDR call)
+{
+  /* The type description for the Entry_Call_Record, and the index of
+     the field "Self".  For efficiency reasons, these are made static
+     so that we can compute them only once the first time and reuse them
+     later.  */
+  static struct type *atcb_call_type;
+  static int self_fieldno = -1;
+
+  struct value *call_value;
+
+  if (call == 0)
+    return 0;
+
+  if (atcb_call_type == NULL)
+    get_tcb_call_type_info (&atcb_call_type, &self_fieldno);
+
+  call_value = value_from_contents_and_address (atcb_call_type, NULL, call);
+  return value_as_address (value_field (call_value, self_fieldno));
+}
+
+#if 0
+/* FIXME: Now modified and back in breakpoint.c */
+/* breakpoint_task_match (PC) returns true if the breakpoint at PC
+   is valid for current task.  */
+
+int
+breakpoint_task_match (CORE_ADDR pc)
+{
+  const int this_task = get_current_task ();
+  const struct breakpoint *breakpoints = get_breakpoint_chain ();
+  const struct breakpoint *b;
+
+  for (b = breakpoints; b; b = b->next)
+    {
+      if (b->enable_state != bp_disabled
+          && b->enable_state != bp_shlib_disabled
+          && (b->address == 0 || b->address == pc)
+          && (b->task == 0 || b->task == this_task))
+        {
+          return 1;
+        }
+    }
+
+  return 0;
+}
+#endif
+
 /* Print detailed information about specified task */
 
 static void
 info_task (char *arg, int from_tty)
 {
-  void *temp_task;
+#ifdef GNAT_GDB
   struct task_entry *pt, *pt2;
-  void *self_id, *caller;
-  struct task_fields atcb, atcb2;
-  struct entry_call call;
-  int bounds[2];
-  char image[256];
+  CORE_ADDR caller;
   int num;
 
-  /* FIXME: language_ada should be defined in defs.h */
-  /*  if (current_language->la_language != language_ada) 
-     { 
-     printf_filtered ("The current language does not support tasks.\n"); 
-     return; 
-     } 
-   */
+  if (current_language->la_language != language_ada)
+    {
+      printf_filtered ("The current language does not support tasks.\n");
+      return;
+    }
+
+  target_find_new_threads ();
+
   pt = get_entry_vptr (atoi (arg));
   if (pt == NULL)
     {
@@ -310,59 +1069,44 @@ info_task (char *arg, int from_tty)
       return;
     }
 
-  temp_task = pt->task_id;
-
-  /* read the atcb in the inferior */
-  READ_MEMORY ((CORE_ADDR) temp_task, atcb);
-
   /* print the Ada task id */
-  printf_filtered ("Ada Task: %p\n", temp_task);
+  printf_filtered ("Ada Task: %s\n", paddr_nz (pt->task_id));
 
   /* print the name of the task */
-  if (atcb.image.P_ARRAY != NULL)
-    {
-      READ_MEMORY ((CORE_ADDR) EXTRACT_ADDRESS (atcb.image.P_BOUNDS), bounds);
-      bounds[1] = EXTRACT_INT (bounds[1]);
-      read_memory ((CORE_ADDR) EXTRACT_ADDRESS (atcb.image.P_ARRAY),
-		   (char *) &image, bounds[1]);
-      printf_filtered ("Name: %.*s\n", bounds[1], image);
-    }
+  if (pt->atcb.image_len != 0)
+    printf_filtered ("Name: %.*s\n", pt->atcb.image_len, pt->atcb.image);
   else
     printf_filtered ("<no name>\n");
 
   /* print the thread id */
 
-  if ((long) pt->thread < 65536)
-    printf_filtered ("Thread: %ld\n", (long int) pt->thread);
+  if (task_ptid_get_tid (pt->task_ptid) < 65536)
+    printf_filtered
+      ("Thread: %ld\n", (long int) task_ptid_get_tid (pt->task_ptid));
   else
-    printf_filtered ("Thread: %p\n", pt->thread);
+    printf_filtered
+      ("Thread: %#lx\n", (long int) task_ptid_get_tid (pt->task_ptid));
 
-  if ((long) pt->lwp != 0)
+  if (task_ptid_get_lwp (pt->task_ptid) != 0)
     {
-      if ((long) pt->lwp < 65536)
-	printf_filtered ("LWP: %ld\n", (long int) pt->lwp);
+      if ((long) task_ptid_get_lwp (pt->task_ptid) < 65536)
+        printf_filtered
+          ("LWP: %ld\n", (long int) task_ptid_get_lwp (pt->task_ptid));
       else
-	printf_filtered ("LWP: %p\n", pt->lwp);
+        printf_filtered
+          ("LWP: %#lx\n", (long int) task_ptid_get_lwp (pt->task_ptid));
     }
 
   /* print the parent gdb task id */
-  num = get_entry_number (EXTRACT_ADDRESS (atcb.parent));
+  num = get_entry_number (pt->atcb.parent);
   if (num != 0)
     {
       printf_filtered ("Parent: %d", num);
       pt2 = get_entry_vptr (num);
-      READ_MEMORY ((CORE_ADDR) pt2->task_id, atcb2);
 
       /* print the name of the task */
-      if (atcb2.image.P_ARRAY != NULL)
-	{
-	  READ_MEMORY ((CORE_ADDR) EXTRACT_ADDRESS (atcb2.image.P_BOUNDS),
-		       bounds);
-	  bounds[1] = EXTRACT_INT (bounds[1]);
-	  read_memory ((CORE_ADDR) EXTRACT_ADDRESS (atcb2.image.P_ARRAY),
-		       (char *) &image, bounds[1]);
-	  printf_filtered (" (%.*s)\n", bounds[1], image);
-	}
+      if (pt2->atcb.image_len != 0)
+	printf_filtered (" (%.*s)\n", pt2->atcb.image_len, pt2->atcb.image);
       else
 	printf_filtered ("\n");
     }
@@ -370,20 +1114,13 @@ info_task (char *arg, int from_tty)
     printf_filtered ("No parent\n");
 
   /* print the base priority of the task */
-  printf_filtered ("Base Priority: %d\n", EXTRACT_INT (atcb.priority));
+  printf_filtered ("Base Priority: %d\n", pt->atcb.priority);
 
   /* print the current state of the task */
 
   /* check if this task is accepting a rendezvous */
-  if (atcb.call == NULL)
-    caller = NULL;
-  else
-    {
-      READ_MEMORY ((CORE_ADDR) EXTRACT_ADDRESS (atcb.call), call);
-      caller = EXTRACT_ADDRESS (call.self);
-    }
-
-  if (caller != NULL)
+  caller = read_caller (pt->atcb.call);
+  if (caller != 0)
     {
       num = get_entry_number (caller);
       printf_filtered ("Accepting rendezvous with %d", num);
@@ -391,164 +1128,46 @@ info_task (char *arg, int from_tty)
       if (num != 0)
 	{
 	  pt2 = get_entry_vptr (num);
-	  READ_MEMORY ((CORE_ADDR) pt2->task_id, atcb2);
 
 	  /* print the name of the task */
-	  if (atcb2.image.P_ARRAY != NULL)
-	    {
-	      READ_MEMORY ((CORE_ADDR) EXTRACT_ADDRESS (atcb2.image.P_BOUNDS),
-			   bounds);
-	      bounds[1] = EXTRACT_INT (bounds[1]);
-	      read_memory ((CORE_ADDR) EXTRACT_ADDRESS (atcb2.image.P_ARRAY),
-			   (char *) &image, bounds[1]);
-	      printf_filtered (" (%.*s)\n", bounds[1], image);
-	    }
+	  if (pt2->atcb.image_len != 0) {
+	    printf_filtered (" (%.*s)\n", pt2->atcb.image_len, pt2->atcb.image);
+	  }
 	  else
 	    printf_filtered ("\n");
 	}
       else
-	printf_filtered ("\n");
+        printf_filtered ("\n");
     }
   else
-    printf_filtered ("State: %s\n", ada_long_task_states[atcb.state]);
-}
-
-#if 0
-
-/* A useful function that shows the alignment of all the fields in the
-   tasks_fields structure
- */
-
-print_align (void)
-{
-  struct task_fields tf;
-  void *tf_base = &(tf);
-  void *tf_state = &(tf.state);
-  void *tf_entry_num = &(tf.entry_num);
-  void *tf_parent = &(tf.parent);
-  void *tf_priority = &(tf.priority);
-  void *tf_current_priority = &(tf.current_priority);
-  void *tf_image = &(tf.image);
-  void *tf_call = &(tf.call);
-  void *tf_thread = &(tf.thread);
-  void *tf_lwp = &(tf.lwp);
-  printf_filtered ("\n");
-  printf_filtered ("(tf_base = 0x%x)\n", tf_base);
-  printf_filtered ("task_fields.entry_num        at %3d (0x%x)\n",
-		   tf_entry_num - tf_base, tf_entry_num);
-  printf_filtered ("task_fields.state            at %3d (0x%x)\n",
-		   tf_state - tf_base, tf_state);
-  printf_filtered ("task_fields.parent           at %3d (0x%x)\n",
-		   tf_parent - tf_base, tf_parent);
-  printf_filtered ("task_fields.priority         at %3d (0x%x)\n",
-		   tf_priority - tf_base, tf_priority);
-  printf_filtered ("task_fields.current_priority at %3d (0x%x)\n",
-		   tf_current_priority - tf_base, tf_current_priority);
-  printf_filtered ("task_fields.image            at %3d (0x%x)\n",
-		   tf_image - tf_base, tf_image);
-  printf_filtered ("task_fields.call             at %3d (0x%x)\n",
-		   tf_call - tf_base, tf_call);
-  printf_filtered ("task_fields.thread           at %3d (0x%x)\n",
-		   tf_thread - tf_base, tf_thread);
-  printf_filtered ("task_fields.lwp              at %3d (0x%x)\n",
-		   tf_lwp - tf_base, tf_lwp);
-  printf_filtered ("\n");
-}
+    printf_filtered ("State: %s\n", long_task_states[pt->atcb.state]);
 #endif
+}
 
 /* Print information about currently known tasks */
 
 static void
 info_tasks (char *arg, int from_tty)
 {
-  struct value *val;
-  int i, task_number, state;
-  void *temp_task, *temp_tasks[MAX_NUMBER_OF_KNOWN_TASKS];
+#ifdef GNAT_GDB
   struct task_entry *pt;
-  void *self_id, *caller, *thread_id = NULL;
-  struct task_fields atcb;
-  struct entry_call call;
-  int bounds[2];
-  char image[256];
+  CORE_ADDR caller;
+  long thread_id = 0L;
   int size;
   char car;
+  ptid_t current_ptid;
 
 #if defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET)
   pthreadTeb_t thr;
   gdb_gregset_t regs;
 #endif
 
-  static struct symbol *sym;
-  static struct minimal_symbol *msym;
-  static void *known_tasks_addr = NULL;
-
-  int init_only = gdbtk_task_initialization;
-  gdbtk_task_initialization = 0;
-
-  task_number = 0;
-
-  if (PIDGET (inferior_ptid) == 0)
-    {
-      printf_filtered ("The program is not being run under gdb. ");
-      printf_filtered ("Use 'run' or 'attach' first.\n");
-      return;
-    }
-
-  if (ada__tasks_check_symbol_table)
-    {
-      thread_support = 0;
-#if (defined(__alpha__) && defined(__osf__) & !defined(VXWORKS_TARGET)) || \
-    defined (_AIX)
-      thread_support = 1;
-#endif
-
-      msym = lookup_minimal_symbol (KNOWN_TASKS_NAME, NULL, NULL);
-      if (msym != NULL)
-	known_tasks_addr = (void *) SYMBOL_VALUE_ADDRESS (msym);
-      else
-#ifndef VXWORKS_TARGET
-	return;
-#else
-	{
-	  if (target_lookup_symbol (KNOWN_TASKS_NAME, &known_tasks_addr) != 0)
-	    return;
-	}
-#endif
-
-      ada__tasks_check_symbol_table = 0;
-    }
-
-  if (known_tasks_addr == NULL)
-    return;
+  current_ptid = inferior_ptid;
 
 #if !((defined(sun) && defined(__SVR4)) || defined(VXWORKS_TARGET) || defined(__WIN32__) || defined (hpux))
   if (thread_support)
 #endif
-    thread_id = GET_CURRENT_THREAD ();
-
-  /* then we get a list of tasks created */
-
-  init_task_list ();
-
-  READ_MEMORY ((CORE_ADDR) known_tasks_addr, temp_tasks);
-
-  for (i = 0; i < MAX_NUMBER_OF_KNOWN_TASKS; i++)
-    {
-      temp_task = EXTRACT_ADDRESS (temp_tasks[i]);
-
-      if (temp_task != NULL)
-	{
-	  task_number = get_entry_number (temp_task);
-	  if (task_number == 0)
-	    task_number = add_task_entry (temp_task, i);
-	}
-    }
-
-  /* Return without printing anything if this function was called in
-     order to init GDBTK tasking. */
-
-  if (init_only)
-    return;
+    thread_id = GET_CURRENT_THREAD (inferior_ptid);
 
   /* print the header */
 
@@ -563,255 +1182,301 @@ info_tasks (char *arg, int from_tty)
   pt = task_list;
   while (pt)
     {
-      temp_task = pt->task_id;
-
-      /* read the atcb in the inferior */
-      READ_MEMORY ((CORE_ADDR) temp_task, atcb);
-
-      /* store the thread id for future use */
-      pt->thread = EXTRACT_ADDRESS (atcb.thread);
-
-#if defined (linux)
-      pt->lwp = (void *) THREAD_TO_PID (atcb.thread, 0);
-#else
-      pt->lwp = EXTRACT_ADDRESS (atcb.lwp);
-#endif
-
       /* print a star if this task is the current one */
       if (thread_id)
 #if defined (__WIN32__) || defined (SGI) || defined (hpux)
-	printf_filtered (pt->lwp == thread_id ? "*" : " ");
+        printf_filtered
+          (task_ptid_get_lwp (pt->task_ptid) == thread_id ? "*" : " ");
 #else
-	printf_filtered (pt->thread == thread_id ? "*" : " ");
+        printf_filtered
+          (task_ptid_get_thread_id (pt->task_ptid) == thread_id ? "*" : " ");
 #endif
 
       /* print the gdb task id */
       printf_filtered ("%3d", pt->task_num);
 
       /* print the Ada task id */
-#ifndef VXWORKS_TARGET
-      printf_filtered (" %9lx", (long) temp_task);
-#else
-#ifdef TARGET_64
-      printf_filtered (" %#9lx", (unsigned long) pt->thread & 0x3ffffffffff);
-#else
-      printf_filtered (" %#9lx", (long) pt->thread);
-#endif
-#endif
+      printf_filtered (" %9lx", (long) pt->task_id);
 
       /* print the parent gdb task id */
-      printf_filtered
-	(" %4d", get_entry_number (EXTRACT_ADDRESS (atcb.parent)));
+      printf_filtered (" %4d", get_entry_number (pt->atcb.parent));
 
       /* print the base priority of the task */
-      printf_filtered (" %3d", EXTRACT_INT (atcb.priority));
+      printf_filtered (" %3d", pt->atcb.priority);
 
 #if defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET)
-      if (pt->task_num == 1 || atcb.state == Terminated)
-	{
-	  printf_filtered ("  Unknown");
-	  goto next;
-	}
-
-      read_memory ((CORE_ADDR) atcb.thread, &thr, sizeof (thr));
-      current_thread = atcb.thread;
+      if (pt->task_num == 1 || pt->atcb.state == Terminated)
+        {
+          printf_filtered ("  Unknown");
+          goto next;
+        }
+
+      READ_MEMORY (pt->atcb.thread, thr);
+      switch_to_thread (task_ptid_get_ptid (pt->task_ptid));
+      /* ??? Brobecker 2003-03-13: Not sure what the next line is used for.
+         And even if useful, it should probably be replaced by call to
+         task_ptid_get_thread_id.  */
+      current_thread = task_ptid_get_tid (pt->task_ptid);
       regs.regs[SP_REGNUM] = 0;
       if (dec_thread_get_registers (&regs, NULL) == 0)
-	{
-	  pt->stack_per = (100 * ((long) thr.__stack_base -
-				  regs.regs[SP_REGNUM])) / thr.__stack_size;
-	  /* if the thread is terminated but still there, the
-	     stack_base/size values are erroneous. Try to patch it */
-	  if (pt->stack_per < 0 || pt->stack_per > 100)
-	    pt->stack_per = 0;
-	}
+        {
+          pt->stack_per = (100 * ((long) thr.__stack_base -
+                                  regs.regs[SP_REGNUM])) / thr.__stack_size;
+          /* if the thread is terminated but still there, the
+             stack_base/size values are erroneous. Try to patch it */
+          if (pt->stack_per < 0 || pt->stack_per > 100)
+            pt->stack_per = 0;
+        }
+      else
+        {
+          /* Set stack_per to an invalid value to signal that we did not
+             manage to compute its value.  */
+          pt->stack_per = -1;
+        }
 
       /* print information about stack space used in the thread */
       if (thr.__stack_size < 1024 * 1024)
-	{
-	  size = thr.__stack_size / 1024;
-	  car = 'K';
-	}
+        {
+          size = thr.__stack_size / 1024;
+          car = 'K';
+        }
       else if (thr.__stack_size < 1024 * 1024 * 1024)
-	{
-	  size = thr.__stack_size / 1024 / 1024;
-	  car = 'M';
-	}
-      else			/* Who knows... */
-	{
-	  size = thr.__stack_size / 1024 / 1024 / 1024;
-	  car = 'G';
-	}
-      printf_filtered (" %4d%c %2d", size, car, pt->stack_per);
+        {
+          size = thr.__stack_size / 1024 / 1024;
+          car = 'M';
+        }
+      else                      /* Who knows... */
+        {
+          size = thr.__stack_size / 1024 / 1024 / 1024;
+          car = 'G';
+        }
+
+      /* print the stack usage in percent, if available.  */
+      if (pt->stack_per != -1)
+        printf_filtered (" %4d%c %2d", size, car, pt->stack_per);
+      else
+        {
+          /* This error is not serious enough that we should raise
+             an internal error, but print '???' to make it unambiguous
+             that we failed to compute this value.  */
+          printf_filtered (" ???");
+        }
+
     next:
 #endif
 
       /* print the current state of the task */
 
       /* check if this task is accepting a rendezvous */
-      if (atcb.call == NULL)
-	caller = NULL;
-      else
-	{
-	  READ_MEMORY ((CORE_ADDR) EXTRACT_ADDRESS (atcb.call), call);
-	  caller = EXTRACT_ADDRESS (call.self);
-	}
-
-      if (caller != NULL)
-	printf_filtered (" Accepting RV with %-4d",
-			 get_entry_number (caller));
+      caller = read_caller (pt->atcb.call);
+      if (caller != 0)
+        printf_filtered (" Accepting RV with %-4d",
+                         get_entry_number (caller));
       else
-	{
-	  state = atcb.state;
+        {
 #if defined (__WIN32__) || defined (SGI) || defined (hpux)
-	  if (state == Runnable && (thread_id && pt->lwp == thread_id))
+          if (pt->atcb.state == Runnable
+              && (thread_id
+                  && task_ptid_get_lwp (pt->task_ptid) == thread_id))
 #else
-	  if (state == Runnable && (thread_id && pt->thread == thread_id))
+          if (pt->atcb.state == Runnable
+              && (thread_id
+                  && task_ptid_get_thread_id (pt->task_ptid) == thread_id))
 #endif
-	    /* Replace "Runnable" by "Running" if this is the current task */
-	    printf_filtered (" %-22s", "Running");
-	  else
-	    printf_filtered (" %-22s", ada_task_states[state]);
-	}
+            /* Replace "Runnable" by "Running" if this is the current task */
+            printf_filtered (" %-22s", "Running");
+          else
+            printf_filtered (" %-22s", task_states[pt->atcb.state]);
+        }
 
       /* finally, print the name of the task */
-      if (atcb.image.P_ARRAY != NULL)
-	{
-	  READ_MEMORY ((CORE_ADDR) EXTRACT_ADDRESS (atcb.image.P_BOUNDS),
-		       bounds);
-	  bounds[1] = EXTRACT_INT (bounds[1]);
-	  read_memory ((CORE_ADDR) EXTRACT_ADDRESS (atcb.image.P_ARRAY),
-		       (char *) &image, bounds[1]);
-	  printf_filtered (" %.*s\n", bounds[1], image);
-	}
+      if (pt->atcb.image_len != 0) {
+        printf_filtered (" %.*s\n", pt->atcb.image_len, pt->atcb.image);
+      }
       else
 	printf_filtered (" <no name>\n");
 
       pt = pt->next_task;
     }
-}
-
-/* Task list initialization for GDB-Tk.  We basically use info_tasks()
-   to initialize our variables, but abort that function before we
-   actually print anything. */
-
-int
-gdbtk_tcl_tasks_initialize (void)
-{
-  gdbtk_task_initialization = 1;
-  info_tasks ("", gdb_stdout);
-
-  return (task_list != NULL);
+  if (!ptid_equal (inferior_ptid, current_ptid))
+    switch_to_thread (current_ptid);
+#endif
 }
 
 static void
 info_tasks_command (char *arg, int from_tty)
 {
+  const int task_list_built = build_task_list ();
+
+  if (!task_list_built)
+    return;
+
   if (arg == NULL || *arg == '\000')
     info_tasks (arg, from_tty);
   else
     info_task (arg, from_tty);
 }
 
-/* Switch from one thread to another. */
+/* Switch to task indicated by NEW_TASK.  Return 0 iff successful.  */
 
-static void
-switch_to_thread (ptid_t ptid)
+static int
+switch_to_task (struct task_entry *new_task)
 {
-  if (ptid_equal (ptid, inferior_ptid))
-    return;
+#ifdef GNAT_GDB
+  /* Raise an error if task-switching is currently not allowed.  */
+  if (!THREAD_SWITCH_ALLOWED ())
+    error ("Task switching is currently not allowed.");
 
-  inferior_ptid = ptid;
-  flush_cached_frames ();
-  registers_changed ();
-  stop_pc = read_pc ();
-  select_frame (get_current_frame ());
-}
+  if (!task_is_alive (new_task->atcb.state))
+    error ("Can not switch to task %d: Task is no longer running",
+           new_task->task_num);
 
-/* Switch to a specified task. */
+  current_task = new_task->task_num;
+  current_thread = task_ptid_get_thread_id (new_task->task_ptid);
 
-static int
-task_switch (void *tid, void *lwpid)
-{
-  int res = 0, pid;
+  if (current_task_id == -1)
+    {
+      SAVE_TASK_REGISTERS (new_task);
+      current_task_id = ada_get_current_task (inferior_ptid);
+    }
 
-  if (thread_support)
+  if (SPECIAL_THREAD_SUPPORT_ACTIVE ())
     {
+      /* FIXME: Integrate with switch_to_thread */
+      int ret_code;
       flush_cached_frames ();
-
-      if (current_task != current_task_id)
-	{
-	  res = THREAD_FETCH_REGISTERS ();
-	}
+      registers_changed ();
+      if (current_task == current_task_id)
+        {
+          RESTORE_TASK_REGISTERS (new_task);
+          ret_code = 0;
+        }
       else
-	{
-#if (defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET))
-	  supply_gregset (&gregset_saved);
-	  supply_fpregset (&fpregset_saved);
-#endif
-	}
-
-      if (res == 0)
-	stop_pc = read_pc ();
+        ret_code = THREAD_FETCH_REGISTERS ();
+      if (ret_code == 0)
+        stop_pc = read_pc ();
       select_frame (get_current_frame ());
-      return res;
+      return ret_code;
     }
-
+  else if (task_ptid_get_pid (new_task->task_ptid) != 0)        /* ?? */
+    {
+      switch_to_thread (task_ptid_get_ptid (new_task->task_ptid));
+      return 0;
+    }
+#endif
   return -1;
 }
 
+/* Print a message telling the user id of the current task.
+   Print an error message if the application does not appear to
+   be using any Ada task.  */
+
 static void
-task_command (char *tidstr, int from_tty)
+display_current_task_id (void) 
 {
-  int num;
-  struct task_entry *e;
+  const int current_task = ada_get_current_task (inferior_ptid);
 
-  if (!tidstr)
-    error ("Please specify a task ID.  Use the \"info tasks\" command to\n"
-	   "see the IDs of currently known tasks.");
+  if (current_task == -1)
+    printf_filtered ("[Current task is unknown]\n");
+  else
+    printf_filtered ("[Current task is %d]\n", current_task);
+}
+
+/* Parse and evaluate TIDSTR into a task id, and try to switch to
+   that task.  Print an error message if the task switch failed.  */
 
-  num = atoi (tidstr);
-  e = get_entry_vptr (num);
+static void
+task_command_1 (char *tidstr, int from_tty)
+{
+  const int num = value_as_long (parse_and_eval (tidstr));
+  struct task_entry *e = get_entry_vptr (num);
 
   if (e == NULL)
     error ("Task ID %d not known.  Use the \"info tasks\" command to\n"
-	   "see the IDs of currently known tasks.", num);
+           "see the IDs of currently known tasks", num);
 
-  if (current_task_id == -1)
+  if (switch_to_task (e) == 0)
     {
-#if (defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET))
-      fill_gregset (&gregset_saved, -1);
-      fill_fpregset (&fpregset_saved, -1);
-#endif
-      current_task_id = get_current_task ();
-    }
-
-  current_task = num;
-  current_task_index = e->known_tasks_index;
-  current_thread = e->thread;
-  current_lwp = e->lwp;
-  if (task_switch (e->thread, e->lwp) == 0)
-    {
-      /* FIXME: find_printable_frame should be defined in frame.h, and
-         implemented in ada-lang.c */
+      ada_find_printable_frame (get_selected_frame ());
       printf_filtered ("[Switching to task %d]\n", num);
-      print_stack_frame (get_selected_frame (), 1, SRC_AND_LOC);
+      print_stack_frame (get_selected_frame (),
+                         frame_relative_level (get_selected_frame ()), 1);
     }
   else
     printf_filtered ("Unable to switch to task %d\n", num);
 }
 
+/* Switch to task indicated in TIDSTR.  Simply print the current task
+   if TIDSTR is empty or NULL.  */
+
+static void
+task_command (char *tidstr, int from_tty)
+{
+  const int task_list_built = build_task_list ();
+
+  if (!task_list_built)
+    return;
+
+  if (tidstr == NULL || tidstr[0] == '\0')
+    display_current_task_id ();
+  else
+    task_command_1 (tidstr, from_tty);
+}
+
+#if defined (__fsu__) || (defined(__alpha__) && defined(__osf__) && !defined(VXWORKS_TARGET))
+/* Restore saved registers if there was a task switch.  */
+void
+ada_reset_thread_registers (void)
+{
+  if (current_task_id != -1 && SPECIAL_THREAD_SUPPORT_ACTIVE ())
+    {
+      supply_gregset (&gregset_saved);
+      supply_fpregset (&fpregset_saved);
+      reinit_frame_cache ();
+      stop_pc = read_pc ();
+    }
+  current_task_id = -1;
+}
+#else
+void
+ada_reset_thread_registers (void)
+{
+}
+#endif
+
+/* The 'normal_stop' observer notification callback.  */
+
+static void
+normal_stop_notification (void)
+{
+  /* The inferior has been resumed, and just stopped. This means that
+     our task_list needs to be recomputed before it can be used again.  */
+  stale_task_list_p = 1;
+}
+
+/* Attach all the observers needed by the ada-tasks module.  */
+
+static void
+ada_tasks_attach_observers (void)
+{
+  observer_attach_normal_stop (&normal_stop_notification);
+}
+
 void
 _initialize_tasks (void)
 {
-  static struct cmd_list_element *task_cmd_list = NULL;
+#ifdef GNAT_GDB
   extern struct cmd_list_element *cmdlist;
 
+  ada_tasks_attach_observers ();
+
   add_info ("tasks", info_tasks_command,
-	    "Without argument: list all known Ada tasks, with status information.\n"
-	    "info tasks n: print detailed information of task n.\n");
+            "Without argument: list all known Ada tasks, with status information.\n"
+            "info tasks n: print detailed information of task n.");
 
-  add_prefix_cmd ("task", class_run, task_command,
-		  "Use this command to switch between tasks.\n\
- The new task ID must be currently known.", &task_cmd_list, "task ", 1, &cmdlist);
+  add_cmd ("task", class_run, task_command,
+           "Without argument: print the current task ID.\n"
+           "task n: Use this command to switch to task n.",
+           &cmdlist);
+#endif
 }