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/* Interface between GDB and target environments, including files and processes

   Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,

   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

   Free Software Foundation, Inc.

   Contributed by Cygnus Support.  Written by John Gilmore.

   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/>.  */

#if !defined (TARGET_H)

#define TARGET_H

struct objfile;

struct ui_file;

struct mem_attrib;

struct target_ops;

struct bp_target_info;

struct regcache;

struct target_section_table;

struct trace_state_variable;

struct trace_status;

struct uploaded_tsv;

struct uploaded_tp;

struct static_tracepoint_marker;

struct expression;

/* This include file defines the interface between the main part

   of the debugger, and the part which is target-specific, or

   specific to the communications interface between us and the

   target.

   A TARGET is an interface between the debugger and a particular

   kind of file or process.  Targets can be STACKED in STRATA,

   so that more than one target can potentially respond to a request.

   In particular, memory accesses will walk down the stack of targets

   until they find a target that is interested in handling that particular

   address.  STRATA are artificial boundaries on the stack, within

   which particular kinds of targets live.  Strata exist so that

   people don't get confused by pushing e.g. a process target and then

   a file target, and wondering why they can't see the current values

   of variables any more (the file target is handling them and they

   never get to the process target).  So when you push a file target,

   it goes into the file stratum, which is always below the process

   stratum.  */

#include "bfd.h"

#include "symtab.h"

#include "memattr.h"

#include "vec.h"

#include "gdb_signals.h"

enum strata

  {

    dummy_stratum,              /* The lowest of the low */

    file_stratum,               /* Executable files, etc */

    core_stratum,               /* Core dump files */

    process_stratum,            /* Executing processes */

    thread_stratum,             /* Executing threads */

    record_stratum,             /* Support record debugging */

    arch_stratum                /* Architecture overrides */

  };

enum thread_control_capabilities

  {

    tc_none = 0,         /* Default: can't control thread execution.  */

    tc_schedlock = 1,           /* Can lock the thread scheduler.  */

  };

/* Stuff for target_wait.  */

/* Generally, what has the program done?  */

enum target_waitkind

  {

    /* The program has exited.  The exit status is in value.integer.  */

    TARGET_WAITKIND_EXITED,

    /* The program has stopped with a signal.  Which signal is in

       value.sig.  */

    TARGET_WAITKIND_STOPPED,

    /* The program has terminated with a signal.  Which signal is in

       value.sig.  */

    TARGET_WAITKIND_SIGNALLED,

    /* The program is letting us know that it dynamically loaded something

       (e.g. it called load(2) on AIX).  */

    TARGET_WAITKIND_LOADED,

    /* The program has forked.  A "related" process' PTID is in

       value.related_pid.  I.e., if the child forks, value.related_pid

       is the parent's ID.  */

    TARGET_WAITKIND_FORKED,

    /* The program has vforked.  A "related" process's PTID is in

       value.related_pid.  */

    TARGET_WAITKIND_VFORKED,

    /* The program has exec'ed a new executable file.  The new file's

       pathname is pointed to by value.execd_pathname.  */

    TARGET_WAITKIND_EXECD,

    /* The program had previously vforked, and now the child is done

       with the shared memory region, because it exec'ed or exited.

       Note that the event is reported to the vfork parent.  This is

       only used if GDB did not stay attached to the vfork child,

       otherwise, a TARGET_WAITKIND_EXECD or

       TARGET_WAITKIND_EXIT|SIGNALLED event associated with the child

       has the same effect.  */

    TARGET_WAITKIND_VFORK_DONE,

    /* The program has entered or returned from a system call.  On

       HP-UX, this is used in the hardware watchpoint implementation.

       The syscall's unique integer ID number is in value.syscall_id */

    TARGET_WAITKIND_SYSCALL_ENTRY,

    TARGET_WAITKIND_SYSCALL_RETURN,

    /* Nothing happened, but we stopped anyway.  This perhaps should be handled

       within target_wait, but I'm not sure target_wait should be resuming the

       inferior.  */

    TARGET_WAITKIND_SPURIOUS,

    /* An event has occured, but we should wait again.

       Remote_async_wait() returns this when there is an event

       on the inferior, but the rest of the world is not interested in

       it. The inferior has not stopped, but has just sent some output

       to the console, for instance. In this case, we want to go back

       to the event loop and wait there for another event from the

       inferior, rather than being stuck in the remote_async_wait()

       function. This way the event loop is responsive to other events,

       like for instance the user typing.  */

    TARGET_WAITKIND_IGNORE,

    /* The target has run out of history information,

       and cannot run backward any further.  */

    TARGET_WAITKIND_NO_HISTORY

  };

struct target_waitstatus

  {

    enum target_waitkind kind;

    /* Forked child pid, execd pathname, exit status, signal number or

       syscall number.  */

    union

      {

        int integer;

        enum target_signal sig;

        ptid_t related_pid;

        char *execd_pathname;

        int syscall_number;

      }

    value;

  };

/* Options that can be passed to target_wait.  */

/* Return immediately if there's no event already queued.  If this

   options is not requested, target_wait blocks waiting for an

   event.  */

#define TARGET_WNOHANG 1

/* The structure below stores information about a system call.

   It is basically used in the "catch syscall" command, and in

   every function that gives information about a system call.

   It's also good to mention that its fields represent everything

   that we currently know about a syscall in GDB.  */

struct syscall

  {

    /* The syscall number.  */

    int number;

    /* The syscall name.  */

    const char *name;

  };

/* Return a pretty printed form of target_waitstatus.

   Space for the result is malloc'd, caller must free.  */

extern char *target_waitstatus_to_string (const struct target_waitstatus *);

/* Possible types of events that the inferior handler will have to

   deal with.  */

enum inferior_event_type

  {

    /* There is a request to quit the inferior, abandon it.  */

    INF_QUIT_REQ,

    /* Process a normal inferior event which will result in target_wait

       being called.  */

    INF_REG_EVENT,

    /* Deal with an error on the inferior.  */

    INF_ERROR,

    /* We are called because a timer went off.  */

    INF_TIMER,

    /* We are called to do stuff after the inferior stops.  */

    INF_EXEC_COMPLETE,

    /* We are called to do some stuff after the inferior stops, but we

       are expected to reenter the proceed() and

       handle_inferior_event() functions. This is used only in case of

       'step n' like commands.  */

    INF_EXEC_CONTINUE

  };

/* Target objects which can be transfered using target_read,

   target_write, et cetera.  */

enum target_object

{

  /* AVR target specific transfer.  See "avr-tdep.c" and "remote.c".  */

  TARGET_OBJECT_AVR,

  /* SPU target specific transfer.  See "spu-tdep.c".  */

  TARGET_OBJECT_SPU,

  /* Transfer up-to LEN bytes of memory starting at OFFSET.  */

  TARGET_OBJECT_MEMORY,

  /* Memory, avoiding GDB's data cache and trusting the executable.

     Target implementations of to_xfer_partial never need to handle

     this object, and most callers should not use it.  */

  TARGET_OBJECT_RAW_MEMORY,

  /* Memory known to be part of the target's stack.  This is cached even

     if it is not in a region marked as such, since it is known to be

     "normal" RAM.  */

  TARGET_OBJECT_STACK_MEMORY,

  /* Kernel Unwind Table.  See "ia64-tdep.c".  */

  TARGET_OBJECT_UNWIND_TABLE,

  /* Transfer auxilliary vector.  */

  TARGET_OBJECT_AUXV,

  /* StackGhost cookie.  See "sparc-tdep.c".  */

  TARGET_OBJECT_WCOOKIE,

  /* Target memory map in XML format.  */

  TARGET_OBJECT_MEMORY_MAP,

  /* Flash memory.  This object can be used to write contents to

     a previously erased flash memory.  Using it without erasing

     flash can have unexpected results.  Addresses are physical

     address on target, and not relative to flash start.  */

  TARGET_OBJECT_FLASH,

  /* Available target-specific features, e.g. registers and coprocessors.

     See "target-descriptions.c".  ANNEX should never be empty.  */

  TARGET_OBJECT_AVAILABLE_FEATURES,

  /* Currently loaded libraries, in XML format.  */

  TARGET_OBJECT_LIBRARIES,

  /* Get OS specific data.  The ANNEX specifies the type (running

     processes, etc.).  */

  TARGET_OBJECT_OSDATA,

  /* Extra signal info.  Usually the contents of `siginfo_t' on unix

     platforms.  */

  TARGET_OBJECT_SIGNAL_INFO,

  /* The list of threads that are being debugged.  */

  TARGET_OBJECT_THREADS,

  /* Collected static trace data.  */

  TARGET_OBJECT_STATIC_TRACE_DATA,

  /* Possible future objects: TARGET_OBJECT_FILE, ... */

};

/* Enumeration of the kinds of traceframe searches that a target may

   be able to perform.  */

enum trace_find_type

  {

    tfind_number,

    tfind_pc,

    tfind_tp,

    tfind_range,

    tfind_outside,

  };

typedef struct static_tracepoint_marker *static_tracepoint_marker_p;

DEF_VEC_P(static_tracepoint_marker_p);

/* Request that OPS transfer up to LEN 8-bit bytes of the target's

   OBJECT.  The OFFSET, for a seekable object, specifies the

   starting point.  The ANNEX can be used to provide additional

   data-specific information to the target.

   Return the number of bytes actually transfered, or -1 if the

   transfer is not supported or otherwise fails.  Return of a positive

   value less than LEN indicates that no further transfer is possible.

   Unlike the raw to_xfer_partial interface, callers of these

   functions do not need to retry partial transfers.  */

extern LONGEST target_read (struct target_ops *ops,

                            enum target_object object,

                            const char *annex, gdb_byte *buf,

                            ULONGEST offset, LONGEST len);

extern LONGEST target_read_until_error (struct target_ops *ops,

                                        enum target_object object,

                                        const char *annex, gdb_byte *buf,

                                        ULONGEST offset, LONGEST len);

extern LONGEST target_write (struct target_ops *ops,

                             enum target_object object,

                             const char *annex, const gdb_byte *buf,

                             ULONGEST offset, LONGEST len);

/* Similar to target_write, except that it also calls PROGRESS with

   the number of bytes written and the opaque BATON after every

   successful partial write (and before the first write).  This is

   useful for progress reporting and user interaction while writing

   data.  To abort the transfer, the progress callback can throw an

   exception.  */

LONGEST target_write_with_progress (struct target_ops *ops,

                                    enum target_object object,

                                    const char *annex, const gdb_byte *buf,

                                    ULONGEST offset, LONGEST len,

                                    void (*progress) (ULONGEST, void *),

                                    void *baton);

/* Wrapper to perform a full read of unknown size.  OBJECT/ANNEX will

   be read using OPS.  The return value will be -1 if the transfer

   fails or is not supported; 0 if the object is empty; or the length

   of the object otherwise.  If a positive value is returned, a

   sufficiently large buffer will be allocated using xmalloc and

   returned in *BUF_P containing the contents of the object.

   This method should be used for objects sufficiently small to store

   in a single xmalloc'd buffer, when no fixed bound on the object's

   size is known in advance.  Don't try to read TARGET_OBJECT_MEMORY

   through this function.  */

extern LONGEST target_read_alloc (struct target_ops *ops,

                                  enum target_object object,

                                  const char *annex, gdb_byte **buf_p);

/* Read OBJECT/ANNEX using OPS.  The result is NUL-terminated and

   returned as a string, allocated using xmalloc.  If an error occurs

   or the transfer is unsupported, NULL is returned.  Empty objects

   are returned as allocated but empty strings.  A warning is issued

   if the result contains any embedded NUL bytes.  */

extern char *target_read_stralloc (struct target_ops *ops,

                                   enum target_object object,

                                   const char *annex);

/* Wrappers to target read/write that perform memory transfers.  They

   throw an error if the memory transfer fails.

   NOTE: cagney/2003-10-23: The naming schema is lifted from

   "frame.h".  The parameter order is lifted from get_frame_memory,

   which in turn lifted it from read_memory.  */

extern void get_target_memory (struct target_ops *ops, CORE_ADDR addr,

                               gdb_byte *buf, LONGEST len);

extern ULONGEST get_target_memory_unsigned (struct target_ops *ops,

                                            CORE_ADDR addr, int len,

                                            enum bfd_endian byte_order);

struct thread_info;             /* fwd decl for parameter list below: */

struct target_ops

  {

    struct target_ops *beneath; /* To the target under this one.  */

    char *to_shortname;         /* Name this target type */

    char *to_longname;          /* Name for printing */

    char *to_doc;               /* Documentation.  Does not include trailing

                                   newline, and starts with a one-line descrip-

                                   tion (probably similar to to_longname).  */

    /* Per-target scratch pad.  */

    void *to_data;

    /* The open routine takes the rest of the parameters from the

       command, and (if successful) pushes a new target onto the

       stack.  Targets should supply this routine, if only to provide

       an error message.  */

    void (*to_open) (char *, int);

    /* Old targets with a static target vector provide "to_close".

       New re-entrant targets provide "to_xclose" and that is expected

       to xfree everything (including the "struct target_ops").  */

    void (*to_xclose) (struct target_ops *targ, int quitting);

    void (*to_close) (int);

    void (*to_attach) (struct target_ops *ops, char *, int);

    void (*to_post_attach) (int);

    void (*to_detach) (struct target_ops *ops, char *, int);

    void (*to_disconnect) (struct target_ops *, char *, int);

    void (*to_resume) (struct target_ops *, ptid_t, int, enum target_signal);

    ptid_t (*to_wait) (struct target_ops *,

                       ptid_t, struct target_waitstatus *, int);

    void (*to_fetch_registers) (struct target_ops *, struct regcache *, int);

    void (*to_store_registers) (struct target_ops *, struct regcache *, int);

    void (*to_prepare_to_store) (struct regcache *);

    /* Transfer LEN bytes of memory between GDB address MYADDR and

       target address MEMADDR.  If WRITE, transfer them to the target, else

       transfer them from the target.  TARGET is the target from which we

       get this function.

       Return value, N, is one of the following:

       error which prevented us from doing it (FIXME: What about bfd_error?).

       positive (call it N) means that we have transferred N bytes

       starting at MEMADDR.  We might be able to handle more bytes

       beyond this length, but no promises.

       negative (call its absolute value N) means that we cannot

       transfer right at MEMADDR, but we could transfer at least

       something at MEMADDR + N.

       NOTE: cagney/2004-10-01: This has been entirely superseeded by

       to_xfer_partial and inferior inheritance.  */

    int (*deprecated_xfer_memory) (CORE_ADDR memaddr, gdb_byte *myaddr,

                                   int len, int write,

                                   struct mem_attrib *attrib,

                                   struct target_ops *target);

    void (*to_files_info) (struct target_ops *);

    int (*to_insert_breakpoint) (struct gdbarch *, struct bp_target_info *);

    int (*to_remove_breakpoint) (struct gdbarch *, struct bp_target_info *);

    int (*to_can_use_hw_breakpoint) (int, int, int);

    int (*to_insert_hw_breakpoint) (struct gdbarch *, struct bp_target_info *);

    int (*to_remove_hw_breakpoint) (struct gdbarch *, struct bp_target_info *);

    /* Documentation of what the two routines below are expected to do is

       provided with the corresponding target_* macros.  */

    int (*to_remove_watchpoint) (CORE_ADDR, int, int, struct expression *);

    int (*to_insert_watchpoint) (CORE_ADDR, int, int, struct expression *);

    int (*to_stopped_by_watchpoint) (void);

    int to_have_steppable_watchpoint;

    int to_have_continuable_watchpoint;

    int (*to_stopped_data_address) (struct target_ops *, CORE_ADDR *);

    int (*to_watchpoint_addr_within_range) (struct target_ops *,

                                            CORE_ADDR, CORE_ADDR, int);

    int (*to_region_ok_for_hw_watchpoint) (CORE_ADDR, int);

    int (*to_can_accel_watchpoint_condition) (CORE_ADDR, int, int,

                                              struct expression *);

    void (*to_terminal_init) (void);

    void (*to_terminal_inferior) (void);

    void (*to_terminal_ours_for_output) (void);

    void (*to_terminal_ours) (void);

    void (*to_terminal_save_ours) (void);

    void (*to_terminal_info) (char *, int);

    void (*to_kill) (struct target_ops *);

    void (*to_load) (char *, int);

    int (*to_lookup_symbol) (char *, CORE_ADDR *);

    void (*to_create_inferior) (struct target_ops *,

                                char *, char *, char **, int);

    void (*to_post_startup_inferior) (ptid_t);

    void (*to_acknowledge_created_inferior) (int);

    void (*to_insert_fork_catchpoint) (int);

    int (*to_remove_fork_catchpoint) (int);

    void (*to_insert_vfork_catchpoint) (int);

    int (*to_remove_vfork_catchpoint) (int);

    int (*to_follow_fork) (struct target_ops *, int);

    void (*to_insert_exec_catchpoint) (int);

    int (*to_remove_exec_catchpoint) (int);

    int (*to_set_syscall_catchpoint) (int, int, int, int, int *);

    int (*to_has_exited) (int, int, int *);

    void (*to_mourn_inferior) (struct target_ops *);

    int (*to_can_run) (void);

    void (*to_notice_signals) (ptid_t ptid);

    int (*to_thread_alive) (struct target_ops *, ptid_t ptid);

    void (*to_find_new_threads) (struct target_ops *);

    char *(*to_pid_to_str) (struct target_ops *, ptid_t);

    char *(*to_extra_thread_info) (struct thread_info *);

    void (*to_stop) (ptid_t);

    void (*to_rcmd) (char *command, struct ui_file *output);

    char *(*to_pid_to_exec_file) (int pid);

    void (*to_log_command) (const char *);

    struct target_section_table *(*to_get_section_table) (struct target_ops *);

    enum strata to_stratum;

    int (*to_has_all_memory) (struct target_ops *);

    int (*to_has_memory) (struct target_ops *);

    int (*to_has_stack) (struct target_ops *);

    int (*to_has_registers) (struct target_ops *);

    int (*to_has_execution) (struct target_ops *);

    int to_has_thread_control;  /* control thread execution */

    int to_attach_no_wait;

    /* ASYNC target controls */

    int (*to_can_async_p) (void);

    int (*to_is_async_p) (void);

    void (*to_async) (void (*) (enum inferior_event_type, void *), void *);

    int (*to_async_mask) (int);

    int (*to_supports_non_stop) (void);

    /* find_memory_regions support method for gcore */

    int (*to_find_memory_regions) (int (*) (CORE_ADDR,

                                            unsigned long,

                                            int, int, int,

                                            void *),

                                   void *);

    /* make_corefile_notes support method for gcore */

    char * (*to_make_corefile_notes) (bfd *, int *);

    /* get_bookmark support method for bookmarks */

    gdb_byte * (*to_get_bookmark) (char *, int);

    /* goto_bookmark support method for bookmarks */

    void (*to_goto_bookmark) (gdb_byte *, int);

    /* Return the thread-local address at OFFSET in the

       thread-local storage for the thread PTID and the shared library

       or executable file given by OBJFILE.  If that block of

       thread-local storage hasn't been allocated yet, this function

       may return an error.  */

    CORE_ADDR (*to_get_thread_local_address) (struct target_ops *ops,

                                              ptid_t ptid,

                                              CORE_ADDR load_module_addr,

                                              CORE_ADDR offset);

    /* Request that OPS transfer up to LEN 8-bit bytes of the target's

       OBJECT.  The OFFSET, for a seekable object, specifies the

       starting point.  The ANNEX can be used to provide additional

       data-specific information to the target.

       Return the number of bytes actually transfered, zero when no

       further transfer is possible, and -1 when the transfer is not

       supported.  Return of a positive value smaller than LEN does

       not indicate the end of the object, only the end of the

       transfer; higher level code should continue transferring if

       desired.  This is handled in target.c.

       The interface does not support a "retry" mechanism.  Instead it

       assumes that at least one byte will be transfered on each

       successful call.

       NOTE: cagney/2003-10-17: The current interface can lead to

       fragmented transfers.  Lower target levels should not implement

       hacks, such as enlarging the transfer, in an attempt to

       compensate for this.  Instead, the target stack should be

       extended so that it implements supply/collect methods and a

       look-aside object cache.  With that available, the lowest

       target can safely and freely "push" data up the stack.

       See target_read and target_write for more information.  One,

       and only one, of readbuf or writebuf must be non-NULL.  */

    LONGEST (*to_xfer_partial) (struct target_ops *ops,

                                enum target_object object, const char *annex,

                                gdb_byte *readbuf, const gdb_byte *writebuf,

                                ULONGEST offset, LONGEST len);

    /* Returns the memory map for the target.  A return value of NULL

       means that no memory map is available.  If a memory address

       does not fall within any returned regions, it's assumed to be

       RAM.  The returned memory regions should not overlap.

       The order of regions does not matter; target_memory_map will

       sort regions by starting address. For that reason, this

       function should not be called directly except via

       target_memory_map.

       This method should not cache data; if the memory map could

       change unexpectedly, it should be invalidated, and higher

       layers will re-fetch it.  */

    VEC(mem_region_s) *(*to_memory_map) (struct target_ops *);

    /* Erases the region of flash memory starting at ADDRESS, of

       length LENGTH.

       Precondition: both ADDRESS and ADDRESS+LENGTH should be aligned

       on flash block boundaries, as reported by 'to_memory_map'.  */

    void (*to_flash_erase) (struct target_ops *,

                           ULONGEST address, LONGEST length);

    /* Finishes a flash memory write sequence.  After this operation

       all flash memory should be available for writing and the result

       of reading from areas written by 'to_flash_write' should be

       equal to what was written.  */

    void (*to_flash_done) (struct target_ops *);

    /* Describe the architecture-specific features of this target.

       Returns the description found, or NULL if no description

       was available.  */

    const struct target_desc *(*to_read_description) (struct target_ops *ops);

    /* Build the PTID of the thread on which a given task is running,

       based on LWP and THREAD.  These values are extracted from the

       task Private_Data section of the Ada Task Control Block, and

       their interpretation depends on the target.  */

    ptid_t (*to_get_ada_task_ptid) (long lwp, long thread);

    /* Read one auxv entry from *READPTR, not reading locations >= ENDPTR.

       Return 0 if *READPTR is already at the end of the buffer.

       Return -1 if there is insufficient buffer for a whole entry.

       Return 1 if an entry was read into *TYPEP and *VALP.  */

    int (*to_auxv_parse) (struct target_ops *ops, gdb_byte **readptr,

                         gdb_byte *endptr, CORE_ADDR *typep, CORE_ADDR *valp);

    /* Search SEARCH_SPACE_LEN bytes beginning at START_ADDR for the

       sequence of bytes in PATTERN with length PATTERN_LEN.

       The result is 1 if found, 0 if not found, and -1 if there was an error

       requiring halting of the search (e.g. memory read error).

       If the pattern is found the address is recorded in FOUND_ADDRP.  */

    int (*to_search_memory) (struct target_ops *ops,

                             CORE_ADDR start_addr, ULONGEST search_space_len,

                             const gdb_byte *pattern, ULONGEST pattern_len,

                             CORE_ADDR *found_addrp);

    /* Can target execute in reverse?  */

    int (*to_can_execute_reverse) (void);

    /* Does this target support debugging multiple processes

       simultaneously?  */

    int (*to_supports_multi_process) (void);

    /* Determine current architecture of thread PTID.

       The target is supposed to determine the architecture of the code where

       the target is currently stopped at (on Cell, if a target is in spu_run,

       to_thread_architecture would return SPU, otherwise PPC32 or PPC64).

       This is architecture used to perform decr_pc_after_break adjustment,

       and also determines the frame architecture of the innermost frame.

       ptrace operations need to operate according to target_gdbarch.

       The default implementation always returns target_gdbarch.  */

    struct gdbarch *(*to_thread_architecture) (struct target_ops *, ptid_t);

    /* Determine current address space of thread PTID.

       The default implementation always returns the inferior's

       address space.  */

    struct address_space *(*to_thread_address_space) (struct target_ops *,

                                                      ptid_t);

    /* Tracepoint-related operations.  */

    /* Prepare the target for a tracing run.  */

    void (*to_trace_init) (void);

    /* Send full details of a tracepoint to the target.  */

    void (*to_download_tracepoint) (struct breakpoint *t);

    /* Send full details of a trace state variable to the target.  */

    void (*to_download_trace_state_variable) (struct trace_state_variable *tsv);

    /* Inform the target info of memory regions that are readonly

       (such as text sections), and so it should return data from

       those rather than look in the trace buffer.  */

    void (*to_trace_set_readonly_regions) (void);

    /* Start a trace run.  */

    void (*to_trace_start) (void);

    /* Get the current status of a tracing run.  */

    int (*to_get_trace_status) (struct trace_status *ts);

    /* Stop a trace run.  */

    void (*to_trace_stop) (void);

   /* Ask the target to find a trace frame of the given type TYPE,

      using NUM, ADDR1, and ADDR2 as search parameters.  Returns the

      number of the trace frame, and also the tracepoint number at

      TPP.  If no trace frame matches, return -1. May throw if the

      operation fails.  */

    int (*to_trace_find) (enum trace_find_type type, int num,

                          ULONGEST addr1, ULONGEST addr2, int *tpp);

    /* Get the value of the trace state variable number TSV, returning

       1 if the value is known and writing the value itself into the

       location pointed to by VAL, else returning 0.  */

    int (*to_get_trace_state_variable_value) (int tsv, LONGEST *val);

    int (*to_save_trace_data) (const char *filename);

    int (*to_upload_tracepoints) (struct uploaded_tp **utpp);

    int (*to_upload_trace_state_variables) (struct uploaded_tsv **utsvp);

    LONGEST (*to_get_raw_trace_data) (gdb_byte *buf,

                                      ULONGEST offset, LONGEST len);

    /* Set the target's tracing behavior in response to unexpected

       disconnection - set VAL to 1 to keep tracing, 0 to stop.  */

    void (*to_set_disconnected_tracing) (int val);

    void (*to_set_circular_trace_buffer) (int val);

    /* Return the processor core that thread PTID was last seen on.

       This information is updated only when:

       - update_thread_list is called

       - thread stops

       If the core cannot be determined -- either for the specified thread, or

       right now, or in this debug session, or for this target -- return -1.  */

    int (*to_core_of_thread) (struct target_ops *, ptid_t ptid);

    /* Verify that the memory in the [MEMADDR, MEMADDR+SIZE) range

       matches the contents of [DATA,DATA+SIZE).  Returns 1 if there's

       a match, 0 if there's a mismatch, and -1 if an error is

       encountered while reading memory.  */

    int (*to_verify_memory) (struct target_ops *, const gdb_byte *data,

                             CORE_ADDR memaddr, ULONGEST size);

    /* Return the address of the start of the Thread Information Block

       a Windows OS specific feature.  */

    int (*to_get_tib_address) (ptid_t ptid, CORE_ADDR *addr);

    /* Send the new settings of write permission variables.  */

    void (*to_set_permissions) (void);

    /* Look for a static tracepoint marker at ADDR, and fill in MARKER

       with its details.  Return 1 on success, 0 on failure.  */

    int (*to_static_tracepoint_marker_at) (CORE_ADDR,

                                           struct static_tracepoint_marker *marker);

    /* Return a vector of all tracepoints markers string id ID, or all

       markers if ID is NULL.  */

    VEC(static_tracepoint_marker_p) *(*to_static_tracepoint_markers_by_strid)

      (const char *id);

    int to_magic;

    /* Need sub-structure for target machine related rather than comm related?

     */

  };