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binutils-gdb/gdb/tracefile-tfile.c
Pedro Alves 5b6d1e4fa4 Multi-target support 
This commit adds multi-target support to GDB.  What this means is that
with this commit, GDB can now be connected to different targets at the
same time.  E.g., you can debug a live native process and a core dump
at the same time, connect to multiple gdbservers, etc.

Actually, the word "target" is overloaded in gdb.  We already have a
target stack, with pushes several target_ops instances on top of one
another.  We also have "info target" already, which means something
completely different to what this patch does.

So from here on, I'll be using the "target connections" term, to mean
an open process_stratum target, pushed on a target stack.  This patch
makes gdb have multiple target stacks, and multiple process_stratum
targets open simultaneously.  The user-visible changes / commands will
also use this terminology, but of course it's all open to debate.

User-interface-wise, not that much changes.  The main difference is
that each inferior may have its own target connection.

A target connection (e.g., a target extended-remote connection) may
support debugging multiple processes, just as before.

Say you're debugging against gdbserver in extended-remote mode, and
you do "add-inferior" to prepare to spawn a new process, like:

 (gdb) target extended-remote :9999
 ...
 (gdb) start
 ...
 (gdb) add-inferior
 Added inferior 2
 (gdb) inferior 2
 [Switching to inferior 2 [<null>] (<noexec>)]
 (gdb) file a.out
 ...
 (gdb) start
 ...

At this point, you have two inferiors connected to the same gdbserver.

With this commit, GDB will maintain a target stack per inferior,
instead of a global target stack.

To preserve the behavior above, by default, "add-inferior" makes the
new inferior inherit a copy of the target stack of the current
inferior.  Same across a fork - the child inherits a copy of the
target stack of the parent.  While the target stacks are copied, the
targets themselves are not.  Instead, target_ops is made a
refcounted_object, which means that target_ops instances are
refcounted, which each inferior counting for a reference.

What if you want to create an inferior and connect it to some _other_
target?  For that, this commit introduces a new "add-inferior
-no-connection" option that makes the new inferior not share the
current inferior's target.  So you could do:

 (gdb) target extended-remote :9999
 Remote debugging using :9999
 ...
 (gdb) add-inferior -no-connection
 [New inferior 2]
 Added inferior 2
 (gdb) inferior 2
 [Switching to inferior 2 [<null>] (<noexec>)]
 (gdb) info inferiors
   Num  Description       Executable
   1    process 18401     target:/home/pedro/tmp/main
 * 2    <null>
 (gdb) tar extended-remote :10000
 Remote debugging using :10000
 ...
 (gdb) info inferiors
   Num  Description       Executable
   1    process 18401     target:/home/pedro/tmp/main
 * 2    process 18450     target:/home/pedro/tmp/main
 (gdb)

A following patch will extended "info inferiors" to include a column
indicating which connection an inferior is bound to, along with a
couple other UI tweaks.

Other than that, debugging is the same as before.  Users interact with
inferiors and threads as before.  The only difference is that
inferiors may be bound to processes running in different machines.

That's pretty much all there is to it in terms of noticeable UI
changes.

On to implementation.

Since we can be connected to different systems at the same time, a
ptid_t is no longer a unique identifier.  Instead a thread can be
identified by a pair of ptid_t and 'process_stratum_target *', the
later being the instance of the process_stratum target that owns the
process/thread.  Note that process_stratum_target inherits from
target_ops, and all process_stratum targets inherit from
process_stratum_target.  In earlier patches, many places in gdb were
converted to refer to threads by thread_info pointer instead of
ptid_t, but there are still places in gdb where we start with a
pid/tid and need to find the corresponding inferior or thread_info
objects.  So you'll see in the patch many places adding a
process_stratum_target parameter to functions that used to take only a
ptid_t.

Since each inferior has its own target stack now, we can always find
the process_stratum target for an inferior.  That is done via a
inf->process_target() convenience method.

Since each inferior has its own target stack, we need to handle the
"beneath" calls when servicing target calls.  The solution I settled
with is just to make sure to switch the current inferior to the
inferior you want before making a target call.  Not relying on global
context is just not feasible in current GDB.  Fortunately, there
aren't that many places that need to do that, because generally most
code that calls target methods already has the current context
pointing to the right inferior/thread.  Note, to emphasize -- there's
no method to "switch to this target stack".  Instead, you switch the
current inferior, and that implicitly switches the target stack.

In some spots, we need to iterate over all inferiors so that we reach
all target stacks.

Native targets are still singletons.  There's always only a single
instance of such targets.

Remote targets however, we'll have one instance per remote connection.

The exec target is still a singleton.  There's only one instance.  I
did not see the point of instanciating more than one exec_target
object.

After vfork, we need to make sure to push the exec target on the new
inferior.  See exec_on_vfork.

For type safety, functions that need a {target, ptid} pair to identify
a thread, take a process_stratum_target pointer for target parameter
instead of target_ops *.  Some shared code in gdb/nat/ also need to
gain a target pointer parameter.  This poses an issue, since gdbserver
doesn't have process_stratum_target, only target_ops.  To fix this,
this commit renames gdbserver's target_ops to process_stratum_target.
I think this makes sense.  There's no concept of target stack in
gdbserver, and gdbserver's target_ops really implements a
process_stratum-like target.

The thread and inferior iterator functions also gain
process_stratum_target parameters.  These are used to be able to
iterate over threads and inferiors of a given target.  Following usual
conventions, if the target pointer is null, then we iterate over
threads and inferiors of all targets.

I tried converting "add-inferior" to the gdb::option framework, as a
preparatory patch, but that stumbled on the fact that gdb::option does
not support file options yet, for "add-inferior -exec".  I have a WIP
patchset that adds that, but it's not a trivial patch, mainly due to
need to integrate readline's filename completion, so I deferred that
to some other time.

In infrun.c/infcmd.c, the main change is that we need to poll events
out of all targets.  See do_target_wait.  Right after collecting an
event, we switch the current inferior to an inferior bound to the
target that reported the event, so that target methods can be used
while handling the event.  This makes most of the code transparent to
multi-targets.  See fetch_inferior_event.

infrun.c:stop_all_threads is interesting -- in this function we need
to stop all threads of all targets.  What the function does is send an
asynchronous stop request to all threads, and then synchronously waits
for events, with target_wait, rinse repeat, until all it finds are
stopped threads.  Now that we have multiple targets, it's not
efficient to synchronously block in target_wait waiting for events out
of one target.  Instead, we implement a mini event loop, with
interruptible_select, select'ing on one file descriptor per target.
For this to work, we need to be able to ask the target for a waitable
file descriptor.  Such file descriptors already exist, they are the
descriptors registered in the main event loop with add_file_handler,
inside the target_async implementations.  This commit adds a new
target_async_wait_fd target method that just returns the file
descriptor in question.  See wait_one / stop_all_threads in infrun.c.

The 'threads_executing' global is made a per-target variable.  Since
it is only relevant to process_stratum_target targets, this is where
it is put, instead of in target_ops.

You'll notice that remote.c includes some FIXME notes.  These refer to
the fact that the global arrays that hold data for the remote packets
supported are still globals.  For example, if we connect to two
different servers/stubs, then each might support different remote
protocol features.  They might even be different architectures, like
e.g., one ARM baremetal stub, and a x86 gdbserver, to debug a
host/controller scenario as a single program.  That isn't going to
work correctly today, because of said globals.  I'm leaving fixing
that for another pass, since it does not appear to be trivial, and I'd
rather land the base work first.  It's already useful to be able to
debug multiple instances of the same server (e.g., a distributed
cluster, where you have full control over the servers installed), so I
think as is it's already reasonable incremental progress.

Current limitations:

 - You can only resume more that one target at the same time if all
   targets support asynchronous debugging, and support non-stop mode.
   It should be possible to support mixed all-stop + non-stop
   backends, but that is left for another time.  This means that
   currently in order to do multi-target with gdbserver you need to
   issue "maint set target-non-stop on".  I would like to make that
   mode be the default, but we're not there yet.  Note that I'm
   talking about how the target backend works, only.  User-visible
   all-stop mode works just fine.

 - As explained above, connecting to different remote servers at the
   same time is likely to produce bad results if they don't support the
   exact set of RSP features.

FreeBSD updates courtesy of John Baldwin.

gdb/ChangeLog:
2020-01-10  Pedro Alves  <palves@redhat.com>
	    John Baldwin  <jhb@FreeBSD.org>

	* aarch64-linux-nat.c
	(aarch64_linux_nat_target::thread_architecture): Adjust.
	* ada-tasks.c (print_ada_task_info): Adjust find_thread_ptid call.
	(task_command_1): Likewise.
	* aix-thread.c (sync_threadlists, aix_thread_target::resume)
	(aix_thread_target::wait, aix_thread_target::fetch_registers)
	(aix_thread_target::store_registers)
	(aix_thread_target::thread_alive): Adjust.
	* amd64-fbsd-tdep.c: Include "inferior.h".
	(amd64fbsd_get_thread_local_address): Pass down target.
	* amd64-linux-nat.c (ps_get_thread_area): Use ps_prochandle
	thread's gdbarch instead of target_gdbarch.
	* break-catch-sig.c (signal_catchpoint_print_it): Adjust call to
	get_last_target_status.
	* break-catch-syscall.c (print_it_catch_syscall): Likewise.
	* breakpoint.c (breakpoints_should_be_inserted_now): Consider all
	inferiors.
	(update_inserted_breakpoint_locations): Skip if inferiors with no
	execution.
	(update_global_location_list): When handling moribund locations,
	find representative inferior for location's pspace, and use thread
	count of its process_stratum target.
	* bsd-kvm.c (bsd_kvm_target_open): Pass target down.
	* bsd-uthread.c (bsd_uthread_target::wait): Use
	as_process_stratum_target and adjust thread_change_ptid and
	add_thread calls.
	(bsd_uthread_target::update_thread_list): Use
	as_process_stratum_target and adjust find_thread_ptid,
	thread_change_ptid and add_thread calls.
	* btrace.c (maint_btrace_packet_history_cmd): Adjust
	find_thread_ptid call.
	* corelow.c (add_to_thread_list): Adjust add_thread call.
	(core_target_open): Adjust add_thread_silent and thread_count
	calls.
	(core_target::pid_to_str): Adjust find_inferior_ptid call.
	* ctf.c (ctf_target_open): Adjust add_thread_silent call.
	* event-top.c (async_disconnect): Pop targets from all inferiors.
	* exec.c (add_target_sections): Push exec target on all inferiors
	sharing the program space.
	(remove_target_sections): Remove the exec target from all
	inferiors sharing the program space.
	(exec_on_vfork): New.
	* exec.h (exec_on_vfork): Declare.
	* fbsd-nat.c (fbsd_add_threads): Add fbsd_nat_target parameter.
	Pass it down.
	(fbsd_nat_target::update_thread_list): Adjust.
	(fbsd_nat_target::resume): Adjust.
	(fbsd_handle_debug_trap): Add fbsd_nat_target parameter.  Pass it
	down.
	(fbsd_nat_target::wait, fbsd_nat_target::post_attach): Adjust.
	* fbsd-tdep.c (fbsd_corefile_thread): Adjust
	get_thread_arch_regcache call.
	* fork-child.c (gdb_startup_inferior): Pass target down to
	startup_inferior and set_executing.
	* gdbthread.h (struct process_stratum_target): Forward declare.
	(add_thread, add_thread_silent, add_thread_with_info)
	(in_thread_list): Add process_stratum_target parameter.
	(find_thread_ptid(inferior*, ptid_t)): New overload.
	(find_thread_ptid, thread_change_ptid): Add process_stratum_target
	parameter.
	(all_threads()): Delete overload.
	(all_threads, all_non_exited_threads): Add process_stratum_target
	parameter.
	(all_threads_safe): Use brace initialization.
	(thread_count): Add process_stratum_target parameter.
	(set_resumed, set_running, set_stop_requested, set_executing)
	(threads_are_executing, finish_thread_state): Add
	process_stratum_target parameter.
	(switch_to_thread): Use is_current_thread.
	* i386-fbsd-tdep.c: Include "inferior.h".
	(i386fbsd_get_thread_local_address): Pass down target.
	* i386-linux-nat.c (i386_linux_nat_target::low_resume): Adjust.
	* inf-child.c (inf_child_target::maybe_unpush_target): Remove
	have_inferiors check.
	* inf-ptrace.c (inf_ptrace_target::create_inferior)
	(inf_ptrace_target::attach): Adjust.
	* infcall.c (run_inferior_call): Adjust.
	* infcmd.c (run_command_1): Pass target to
	scoped_finish_thread_state.
	(proceed_thread_callback): Skip inferiors with no execution.
	(continue_command): Rename 'all_threads' local to avoid hiding
	'all_threads' function.  Adjust get_last_target_status call.
	(prepare_one_step): Adjust set_running call.
	(signal_command): Use user_visible_resume_target.  Compare thread
	pointers instead of inferior_ptid.
	(info_program_command): Adjust to pass down target.
	(attach_command): Mark target's 'thread_executing' flag.
	(stop_current_target_threads_ns): New, factored out from ...
	(interrupt_target_1): ... this.  Switch inferior before making
	target calls.
	* inferior-iter.h
	(struct all_inferiors_iterator, struct all_inferiors_range)
	(struct all_inferiors_safe_range)
	(struct all_non_exited_inferiors_range): Filter on
	process_stratum_target too.  Remove explicit.
	* inferior.c (inferior::inferior): Push dummy target on target
	stack.
	(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors):
	Add process_stratum_target parameter, and pass it down.
	(have_live_inferiors): Adjust.
	(switch_to_inferior_and_push_target): New.
	(add_inferior_command, clone_inferior_command): Handle
	"-no-connection" parameter.  Use
	switch_to_inferior_and_push_target.
	(_initialize_inferior): Mention "-no-connection" option in
	the help of "add-inferior" and "clone-inferior" commands.
	* inferior.h: Include "process-stratum-target.h".
	(interrupt_target_1): Use bool.
	(struct inferior) <push_target, unpush_target, target_is_pushed,
	find_target_beneath, top_target, process_target, target_at,
	m_stack>: New.
	(discard_all_inferiors): Delete.
	(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors)
	(all_inferiors, all_non_exited_inferiors): Add
	process_stratum_target parameter.
	* infrun.c: Include "gdb_select.h" and <unordered_map>.
	(target_last_proc_target): New global.
	(follow_fork_inferior): Push target on new inferior.  Pass target
	to add_thread_silent.  Call exec_on_vfork.  Handle target's
	reference count.
	(follow_fork): Adjust get_last_target_status call.  Also consider
	target.
	(follow_exec): Push target on new inferior.
	(struct execution_control_state) <target>: New field.
	(user_visible_resume_target): New.
	(do_target_resume): Call target_async.
	(resume_1): Set target's threads_executing flag.  Consider resume
	target.
	(commit_resume_all_targets): New.
	(proceed): Also consider resume target.  Skip threads of inferiors
	with no execution.  Commit resumtion in all targets.
	(start_remote): Pass current inferior to wait_for_inferior.
	(infrun_thread_stop_requested): Consider target as well.  Pass
	thread_info pointer to clear_inline_frame_state instead of ptid.
	(infrun_thread_thread_exit): Consider target as well.
	(random_pending_event_thread): New inferior parameter.  Use it.
	(do_target_wait): Rename to ...
	(do_target_wait_1): ... this.  Add inferior parameter, and pass it
	down.
	(threads_are_resumed_pending_p, do_target_wait): New.
	(prepare_for_detach): Adjust calls.
	(wait_for_inferior): New inferior parameter.  Handle it.  Use
	do_target_wait_1 instead of do_target_wait.
	(fetch_inferior_event): Adjust.  Switch to representative
	inferior.  Pass target down.
	(set_last_target_status): Add process_stratum_target parameter.
	Save target in global.
	(get_last_target_status): Add process_stratum_target parameter and
	handle it.
	(nullify_last_target_wait_ptid): Clear 'target_last_proc_target'.
	(context_switch): Check inferior_ptid == null_ptid before calling
	inferior_thread().
	(get_inferior_stop_soon): Pass down target.
	(wait_one): Rename to ...
	(poll_one_curr_target): ... this.
	(struct wait_one_event): New.
	(wait_one): New.
	(stop_all_threads): Adjust.
	(handle_no_resumed, handle_inferior_event): Adjust to consider the
	event's target.
	(switch_back_to_stepped_thread): Also consider target.
	(print_stop_event): Update.
	(normal_stop): Update.  Also consider the resume target.
	* infrun.h (wait_for_inferior): Remove declaration.
	(user_visible_resume_target): New declaration.
	(get_last_target_status, set_last_target_status): New
	process_stratum_target parameter.
	* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
	process_stratum_target parameter, and use it.
	(clear_inline_frame_state (thread_info*)): New.
	* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
	process_stratum_target parameter.
	(clear_inline_frame_state (thread_info*)): Declare.
	* linux-fork.c (delete_checkpoint_command): Pass target down to
	find_thread_ptid.
	(checkpoint_command): Adjust.
	* linux-nat.c (linux_nat_target::follow_fork): Switch to thread
	instead of just tweaking inferior_ptid.
	(linux_nat_switch_fork): Pass target down to thread_change_ptid.
	(exit_lwp): Pass target down to find_thread_ptid.
	(attach_proc_task_lwp_callback): Pass target down to
	add_thread/set_running/set_executing.
	(linux_nat_target::attach): Pass target down to
	thread_change_ptid.
	(get_detach_signal): Pass target down to find_thread_ptid.
	Consider last target status's target.
	(linux_resume_one_lwp_throw, resume_lwp)
	(linux_handle_syscall_trap, linux_handle_extended_wait, wait_lwp)
	(stop_wait_callback, save_stop_reason, linux_nat_filter_event)
	(linux_nat_wait_1, resume_stopped_resumed_lwps): Pass target down.
	(linux_nat_target::async_wait_fd): New.
	(linux_nat_stop_lwp, linux_nat_target::thread_address_space): Pass
	target down.
	* linux-nat.h (linux_nat_target::async_wait_fd): Declare.
	* linux-tdep.c (get_thread_arch_regcache): Pass target down.
	* linux-thread-db.c (struct thread_db_info::process_target): New
	field.
	(add_thread_db_info): Save target.
	(get_thread_db_info): New process_stratum_target parameter.  Also
	match target.
	(delete_thread_db_info): New process_stratum_target parameter.
	Also match target.
	(thread_from_lwp): Adjust to pass down target.
	(thread_db_notice_clone): Pass down target.
	(check_thread_db_callback): Pass down target.
	(try_thread_db_load_1): Always push the thread_db target.
	(try_thread_db_load, record_thread): Pass target down.
	(thread_db_target::detach): Pass target down.  Always unpush the
	thread_db target.
	(thread_db_target::wait, thread_db_target::mourn_inferior): Pass
	target down.  Always unpush the thread_db target.
	(find_new_threads_callback, thread_db_find_new_threads_2)
	(thread_db_target::update_thread_list): Pass target down.
	(thread_db_target::pid_to_str): Pass current inferior down.
	(thread_db_target::get_thread_local_address): Pass target down.
	(thread_db_target::resume, maintenance_check_libthread_db): Pass
	target down.
	* nto-procfs.c (nto_procfs_target::update_thread_list): Adjust.
	* procfs.c (procfs_target::procfs_init_inferior): Declare.
	(proc_set_current_signal, do_attach, procfs_target::wait): Adjust.
	(procfs_init_inferior): Rename to ...
	(procfs_target::procfs_init_inferior): ... this and adjust.
	(procfs_target::create_inferior, procfs_notice_thread)
	(procfs_do_thread_registers): Adjust.
	* ppc-fbsd-tdep.c: Include "inferior.h".
	(ppcfbsd_get_thread_local_address): Pass down target.
	* proc-service.c (ps_xfer_memory): Switch current inferior and
	program space as well.
	(get_ps_regcache): Pass target down.
	* process-stratum-target.c
	(process_stratum_target::thread_address_space)
	(process_stratum_target::thread_architecture): Pass target down.
	* process-stratum-target.h
	(process_stratum_target::threads_executing): New field.
	(as_process_stratum_target): New.
	* ravenscar-thread.c
	(ravenscar_thread_target::update_inferior_ptid): Pass target down.
	(ravenscar_thread_target::wait, ravenscar_add_thread): Pass target
	down.
	* record-btrace.c (record_btrace_target::info_record): Adjust.
	(record_btrace_target::record_method)
	(record_btrace_target::record_is_replaying)
	(record_btrace_target::fetch_registers)
	(get_thread_current_frame_id, record_btrace_target::resume)
	(record_btrace_target::wait, record_btrace_target::stop): Pass
	target down.
	* record-full.c (record_full_wait_1): Switch to event thread.
	Pass target down.
	* regcache.c (regcache::regcache)
	(get_thread_arch_aspace_regcache, get_thread_arch_regcache): Add
	process_stratum_target parameter and handle it.
	(current_thread_target): New global.
	(get_thread_regcache): Add process_stratum_target parameter and
	handle it.  Switch inferior before calling target method.
	(get_thread_regcache): Pass target down.
	(get_thread_regcache_for_ptid): Pass target down.
	(registers_changed_ptid): Add process_stratum_target parameter and
	handle it.
	(registers_changed_thread, registers_changed): Pass target down.
	(test_get_thread_arch_aspace_regcache): New.
	(current_regcache_test): Define a couple local test_target_ops
	instances and use them for testing.
	(readwrite_regcache): Pass process_stratum_target parameter.
	(cooked_read_test, cooked_write_test): Pass mock_target down.
	* regcache.h (get_thread_regcache, get_thread_arch_regcache)
	(get_thread_arch_aspace_regcache): Add process_stratum_target
	parameter.
	(regcache::target): New method.
	(regcache::regcache, regcache::get_thread_arch_aspace_regcache)
	(regcache::registers_changed_ptid): Add process_stratum_target
	parameter.
	(regcache::m_target): New field.
	(registers_changed_ptid): Add process_stratum_target parameter.
	* remote.c (remote_state::supports_vCont_probed): New field.
	(remote_target::async_wait_fd): New method.
	(remote_unpush_and_throw): Add remote_target parameter.
	(get_current_remote_target): Adjust.
	(remote_target::remote_add_inferior): Push target.
	(remote_target::remote_add_thread)
	(remote_target::remote_notice_new_inferior)
	(get_remote_thread_info): Pass target down.
	(remote_target::update_thread_list): Skip threads of inferiors
	bound to other targets.  (remote_target::close): Don't discard
	inferiors.  (remote_target::add_current_inferior_and_thread)
	(remote_target::process_initial_stop_replies)
	(remote_target::start_remote)
	(remote_target::remote_serial_quit_handler): Pass down target.
	(remote_target::remote_unpush_target): New remote_target
	parameter.  Unpush the target from all inferiors.
	(remote_target::remote_unpush_and_throw): New remote_target
	parameter.  Pass it down.
	(remote_target::open_1): Check whether the current inferior has
	execution instead of checking whether any inferior is live.  Pass
	target down.
	(remote_target::remote_detach_1): Pass down target.  Use
	remote_unpush_target.
	(extended_remote_target::attach): Pass down target.
	(remote_target::remote_vcont_probe): Set supports_vCont_probed.
	(remote_target::append_resumption): Pass down target.
	(remote_target::append_pending_thread_resumptions)
	(remote_target::remote_resume_with_hc, remote_target::resume)
	(remote_target::commit_resume): Pass down target.
	(remote_target::remote_stop_ns): Check supports_vCont_probed.
	(remote_target::interrupt_query)
	(remote_target::remove_new_fork_children)
	(remote_target::check_pending_events_prevent_wildcard_vcont)
	(remote_target::remote_parse_stop_reply)
	(remote_target::process_stop_reply): Pass down target.
	(first_remote_resumed_thread): New remote_target parameter.  Pass
	it down.
	(remote_target::wait_as): Pass down target.
	(unpush_and_perror): New remote_target parameter.  Pass it down.
	(remote_target::readchar, remote_target::remote_serial_write)
	(remote_target::getpkt_or_notif_sane_1)
	(remote_target::kill_new_fork_children, remote_target::kill): Pass
	down target.
	(remote_target::mourn_inferior): Pass down target.  Use
	remote_unpush_target.
	(remote_target::core_of_thread)
	(remote_target::remote_btrace_maybe_reopen): Pass down target.
	(remote_target::pid_to_exec_file)
	(remote_target::thread_handle_to_thread_info): Pass down target.
	(remote_target::async_wait_fd): New.
	* riscv-fbsd-tdep.c: Include "inferior.h".
	(riscv_fbsd_get_thread_local_address): Pass down target.
	* sol2-tdep.c (sol2_core_pid_to_str): Pass down target.
	* sol-thread.c (sol_thread_target::wait, ps_lgetregs, ps_lsetregs)
	(ps_lgetfpregs, ps_lsetfpregs, sol_update_thread_list_callback):
	Adjust.
	* solib-spu.c (spu_skip_standalone_loader): Pass down target.
	* solib-svr4.c (enable_break): Pass down target.
	* spu-multiarch.c (parse_spufs_run): Pass down target.
	* spu-tdep.c (spu2ppu_sniffer): Pass down target.
	* target-delegates.c: Regenerate.
	* target.c (g_target_stack): Delete.
	(current_top_target): Return the current inferior's top target.
	(target_has_execution_1): Refer to the passed-in inferior's top
	target.
	(target_supports_terminal_ours): Check whether the initial
	inferior was already created.
	(decref_target): New.
	(target_stack::push): Incref/decref the target.
	(push_target, push_target, unpush_target): Adjust.
	(target_stack::unpush): Defref target.
	(target_is_pushed): Return bool.  Adjust to refer to the current
	inferior's target stack.
	(dispose_inferior): Delete, and inline parts ...
	(target_preopen): ... here.  Only dispose of the current inferior.
	(target_detach): Hold strong target reference while detaching.
	Pass target down.
	(target_thread_name): Add assertion.
	(target_resume): Pass down target.
	(target_ops::beneath, find_target_at): Adjust to refer to the
	current inferior's target stack.
	(get_dummy_target): New.
	(target_pass_ctrlc): Pass the Ctrl-C to the first inferior that
	has a thread running.
	(initialize_targets): Rename to ...
	(_initialize_target): ... this.
	* target.h: Include "gdbsupport/refcounted-object.h".
	(struct target_ops): Inherit refcounted_object.
	(target_ops::shortname, target_ops::longname): Make const.
	(target_ops::async_wait_fd): New method.
	(decref_target): Declare.
	(struct target_ops_ref_policy): New.
	(target_ops_ref): New typedef.
	(get_dummy_target): Declare function.
	(target_is_pushed): Return bool.
	* thread-iter.c (all_matching_threads_iterator::m_inf_matches)
	(all_matching_threads_iterator::all_matching_threads_iterator):
	Handle filter target.
	* thread-iter.h (struct all_matching_threads_iterator, struct
	all_matching_threads_range, class all_non_exited_threads_range):
	Filter by target too.  Remove explicit.
	* thread.c (threads_executing): Delete.
	(inferior_thread): Pass down current inferior.
	(clear_thread_inferior_resources): Pass down thread pointer
	instead of ptid_t.
	(add_thread_silent, add_thread_with_info, add_thread): Add
	process_stratum_target parameter.  Use it for thread and inferior
	searches.
	(is_current_thread): New.
	(thread_info::deletable): Use it.
	(find_thread_ptid, thread_count, in_thread_list)
	(thread_change_ptid, set_resumed, set_running): New
	process_stratum_target parameter.  Pass it down.
	(set_executing): New process_stratum_target parameter.  Pass it
	down.  Adjust reference to 'threads_executing'.
	(threads_are_executing): New process_stratum_target parameter.
	Adjust reference to 'threads_executing'.
	(set_stop_requested, finish_thread_state): New
	process_stratum_target parameter.  Pass it down.
	(switch_to_thread): Also match inferior.
	(switch_to_thread): New process_stratum_target parameter.  Pass it
	down.
	(update_threads_executing): Reimplement.
	* top.c (quit_force): Pop targets from all inferior.
	(gdb_init): Don't call initialize_targets.
	* windows-nat.c (windows_nat_target) <get_windows_debug_event>:
	Declare.
	(windows_add_thread, windows_delete_thread): Adjust.
	(get_windows_debug_event): Rename to ...
	(windows_nat_target::get_windows_debug_event): ... this.  Adjust.
	* tracefile-tfile.c (tfile_target_open): Pass down target.
	* gdbsupport/common-gdbthread.h (struct process_stratum_target):
	Forward declare.
	(switch_to_thread): Add process_stratum_target parameter.
	* mi/mi-interp.c (mi_on_resume_1): Add process_stratum_target
	parameter.  Use it.
	(mi_on_resume): Pass target down.
	* nat/fork-inferior.c (startup_inferior): Add
	process_stratum_target parameter.  Pass it down.
	* nat/fork-inferior.h (startup_inferior): Add
	process_stratum_target parameter.
	* python/py-threadevent.c (py_get_event_thread): Pass target down.

gdb/gdbserver/ChangeLog:
2020-01-10  Pedro Alves  <palves@redhat.com>

	* fork-child.c (post_fork_inferior): Pass target down to
	startup_inferior.
	* inferiors.c (switch_to_thread): Add process_stratum_target
	parameter.
	* lynx-low.c (lynx_target_ops): Now a process_stratum_target.
	* nto-low.c (nto_target_ops): Now a process_stratum_target.
	* linux-low.c (linux_target_ops): Now a process_stratum_target.
	* remote-utils.c (prepare_resume_reply): Pass the target to
	switch_to_thread.
	* target.c (the_target): Now a process_stratum_target.
	(done_accessing_memory): Pass the target to switch_to_thread.
	(set_target_ops): Ajust to use process_stratum_target.
	* target.h (struct target_ops): Rename to ...
	(struct process_stratum_target): ... this.
	(the_target, set_target_ops): Adjust.
	(prepare_to_access_memory): Adjust comment.
	* win32-low.c (child_xfer_memory): Adjust to use
	process_stratum_target.
	(win32_target_ops): Now a process_stratum_target.
2020-01-10 20:06:08 +00:00

1139 lines
30 KiB
C
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/* Trace file TFILE format support in GDB.
Copyright (C) 1997-2020 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "tracefile.h"
#include "readline/tilde.h"
#include "gdbsupport/filestuff.h"
#include "gdbsupport/rsp-low.h" /* bin2hex */
#include "regcache.h"
#include "inferior.h"
#include "gdbthread.h"
#include "exec.h" /* exec_bfd */
#include "completer.h"
#include "filenames.h"
#include "remote.h"
#include "xml-tdesc.h"
#include "target-descriptions.h"
#include "gdbsupport/buffer.h"
#include "gdbsupport/pathstuff.h"
#include <algorithm>
#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif
/* The tfile target. */
static const target_info tfile_target_info = {
"tfile",
N_("Local trace dump file"),
N_("Use a trace file as a target.\n\
Specify the filename of the trace file.")
};
class tfile_target final : public tracefile_target
{
public:
const target_info &info () const override
{ return tfile_target_info; }
void close () override;
void fetch_registers (struct regcache *, int) override;
enum target_xfer_status xfer_partial (enum target_object object,
const char *annex,
gdb_byte *readbuf,
const gdb_byte *writebuf,
ULONGEST offset, ULONGEST len,
ULONGEST *xfered_len) override;
void files_info () override;
int trace_find (enum trace_find_type type, int num,
CORE_ADDR addr1, CORE_ADDR addr2, int *tpp) override;
bool get_trace_state_variable_value (int tsv, LONGEST *val) override;
traceframe_info_up traceframe_info () override;
void get_tracepoint_status (struct breakpoint *tp,
struct uploaded_tp *utp) override;
};
/* TFILE trace writer. */
struct tfile_trace_file_writer
{
struct trace_file_writer base;
/* File pointer to tfile trace file. */
FILE *fp;
/* Path name of the tfile trace file. */
char *pathname;
};
/* This is the implementation of trace_file_write_ops method
target_save. We just call the generic target
target_save_trace_data to do target-side saving. */
static int
tfile_target_save (struct trace_file_writer *self,
const char *filename)
{
int err = target_save_trace_data (filename);
return (err >= 0);
}
/* This is the implementation of trace_file_write_ops method
dtor. */
static void
tfile_dtor (struct trace_file_writer *self)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
xfree (writer->pathname);
if (writer->fp != NULL)
fclose (writer->fp);
}
/* This is the implementation of trace_file_write_ops method
start. It creates the trace file FILENAME and registers some
cleanups. */
static void
tfile_start (struct trace_file_writer *self, const char *filename)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
writer->pathname = tilde_expand (filename);
writer->fp = gdb_fopen_cloexec (writer->pathname, "wb").release ();
if (writer->fp == NULL)
error (_("Unable to open file '%s' for saving trace data (%s)"),
writer->pathname, safe_strerror (errno));
}
/* This is the implementation of trace_file_write_ops method
write_header. Write the TFILE header. */
static void
tfile_write_header (struct trace_file_writer *self)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
int written;
/* Write a file header, with a high-bit-set char to indicate a
binary file, plus a hint as what this file is, and a version
number in case of future needs. */
written = fwrite ("\x7fTRACE0\n", 8, 1, writer->fp);
if (written < 1)
perror_with_name (writer->pathname);
}
/* This is the implementation of trace_file_write_ops method
write_regblock_type. Write the size of register block. */
static void
tfile_write_regblock_type (struct trace_file_writer *self, int size)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
fprintf (writer->fp, "R %x\n", size);
}
/* This is the implementation of trace_file_write_ops method
write_status. */
static void
tfile_write_status (struct trace_file_writer *self,
struct trace_status *ts)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
fprintf (writer->fp, "status %c;%s",
(ts->running ? '1' : '0'), stop_reason_names[ts->stop_reason]);
if (ts->stop_reason == tracepoint_error
|| ts->stop_reason == trace_stop_command)
{
char *buf = (char *) alloca (strlen (ts->stop_desc) * 2 + 1);
bin2hex ((gdb_byte *) ts->stop_desc, buf, strlen (ts->stop_desc));
fprintf (writer->fp, ":%s", buf);
}
fprintf (writer->fp, ":%x", ts->stopping_tracepoint);
if (ts->traceframe_count >= 0)
fprintf (writer->fp, ";tframes:%x", ts->traceframe_count);
if (ts->traceframes_created >= 0)
fprintf (writer->fp, ";tcreated:%x", ts->traceframes_created);
if (ts->buffer_free >= 0)
fprintf (writer->fp, ";tfree:%x", ts->buffer_free);
if (ts->buffer_size >= 0)
fprintf (writer->fp, ";tsize:%x", ts->buffer_size);
if (ts->disconnected_tracing)
fprintf (writer->fp, ";disconn:%x", ts->disconnected_tracing);
if (ts->circular_buffer)
fprintf (writer->fp, ";circular:%x", ts->circular_buffer);
if (ts->start_time)
{
fprintf (writer->fp, ";starttime:%s",
phex_nz (ts->start_time, sizeof (ts->start_time)));
}
if (ts->stop_time)
{
fprintf (writer->fp, ";stoptime:%s",
phex_nz (ts->stop_time, sizeof (ts->stop_time)));
}
if (ts->notes != NULL)
{
char *buf = (char *) alloca (strlen (ts->notes) * 2 + 1);
bin2hex ((gdb_byte *) ts->notes, buf, strlen (ts->notes));
fprintf (writer->fp, ";notes:%s", buf);
}
if (ts->user_name != NULL)
{
char *buf = (char *) alloca (strlen (ts->user_name) * 2 + 1);
bin2hex ((gdb_byte *) ts->user_name, buf, strlen (ts->user_name));
fprintf (writer->fp, ";username:%s", buf);
}
fprintf (writer->fp, "\n");
}
/* This is the implementation of trace_file_write_ops method
write_uploaded_tsv. */
static void
tfile_write_uploaded_tsv (struct trace_file_writer *self,
struct uploaded_tsv *utsv)
{
char *buf = NULL;
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
if (utsv->name)
{
buf = (char *) xmalloc (strlen (utsv->name) * 2 + 1);
bin2hex ((gdb_byte *) (utsv->name), buf, strlen (utsv->name));
}
fprintf (writer->fp, "tsv %x:%s:%x:%s\n",
utsv->number, phex_nz (utsv->initial_value, 8),
utsv->builtin, buf != NULL ? buf : "");
if (utsv->name)
xfree (buf);
}
#define MAX_TRACE_UPLOAD 2000
/* This is the implementation of trace_file_write_ops method
write_uploaded_tp. */
static void
tfile_write_uploaded_tp (struct trace_file_writer *self,
struct uploaded_tp *utp)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
char buf[MAX_TRACE_UPLOAD];
fprintf (writer->fp, "tp T%x:%s:%c:%x:%x",
utp->number, phex_nz (utp->addr, sizeof (utp->addr)),
(utp->enabled ? 'E' : 'D'), utp->step, utp->pass);
if (utp->type == bp_fast_tracepoint)
fprintf (writer->fp, ":F%x", utp->orig_size);
if (utp->cond)
fprintf (writer->fp,
":X%x,%s", (unsigned int) strlen (utp->cond.get ()) / 2,
utp->cond.get ());
fprintf (writer->fp, "\n");
for (const auto &act : utp->actions)
fprintf (writer->fp, "tp A%x:%s:%s\n",
utp->number, phex_nz (utp->addr, sizeof (utp->addr)), act.get ());
for (const auto &act : utp->step_actions)
fprintf (writer->fp, "tp S%x:%s:%s\n",
utp->number, phex_nz (utp->addr, sizeof (utp->addr)), act.get ());
if (utp->at_string)
{
encode_source_string (utp->number, utp->addr,
"at", utp->at_string.get (),
buf, MAX_TRACE_UPLOAD);
fprintf (writer->fp, "tp Z%s\n", buf);
}
if (utp->cond_string)
{
encode_source_string (utp->number, utp->addr,
"cond", utp->cond_string.get (),
buf, MAX_TRACE_UPLOAD);
fprintf (writer->fp, "tp Z%s\n", buf);
}
for (const auto &act : utp->cmd_strings)
{
encode_source_string (utp->number, utp->addr, "cmd", act.get (),
buf, MAX_TRACE_UPLOAD);
fprintf (writer->fp, "tp Z%s\n", buf);
}
fprintf (writer->fp, "tp V%x:%s:%x:%s\n",
utp->number, phex_nz (utp->addr, sizeof (utp->addr)),
utp->hit_count,
phex_nz (utp->traceframe_usage,
sizeof (utp->traceframe_usage)));
}
/* This is the implementation of trace_file_write_ops method
write_tdesc. */
static void
tfile_write_tdesc (struct trace_file_writer *self)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
gdb::optional<std::string> tdesc
= target_fetch_description_xml (current_top_target ());
if (!tdesc)
return;
const char *ptr = tdesc->c_str ();
/* Write tdesc line by line, prefixing each line with "tdesc ". */
while (ptr != NULL)
{
const char *next = strchr (ptr, '\n');
if (next != NULL)
{
fprintf (writer->fp, "tdesc %.*s\n", (int) (next - ptr), ptr);
/* Skip the \n. */
next++;
}
else if (*ptr != '\0')
{
/* Last line, doesn't have a newline. */
fprintf (writer->fp, "tdesc %s\n", ptr);
}
ptr = next;
}
}
/* This is the implementation of trace_file_write_ops method
write_definition_end. */
static void
tfile_write_definition_end (struct trace_file_writer *self)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
fprintf (writer->fp, "\n");
}
/* This is the implementation of trace_file_write_ops method
write_raw_data. */
static void
tfile_write_raw_data (struct trace_file_writer *self, gdb_byte *buf,
LONGEST len)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
if (fwrite (buf, len, 1, writer->fp) < 1)
perror_with_name (writer->pathname);
}
/* This is the implementation of trace_file_write_ops method
end. */
static void
tfile_end (struct trace_file_writer *self)
{
struct tfile_trace_file_writer *writer
= (struct tfile_trace_file_writer *) self;
uint32_t gotten = 0;
/* Mark the end of trace data. */
if (fwrite (&gotten, 4, 1, writer->fp) < 1)
perror_with_name (writer->pathname);
}
/* Operations to write trace buffers into TFILE format. */
static const struct trace_file_write_ops tfile_write_ops =
{
tfile_dtor,
tfile_target_save,
tfile_start,
tfile_write_header,
tfile_write_regblock_type,
tfile_write_status,
tfile_write_uploaded_tsv,
tfile_write_uploaded_tp,
tfile_write_tdesc,
tfile_write_definition_end,
tfile_write_raw_data,
NULL,
tfile_end,
};
/* Return a trace writer for TFILE format. */
struct trace_file_writer *
tfile_trace_file_writer_new (void)
{
struct tfile_trace_file_writer *writer
= XNEW (struct tfile_trace_file_writer);
writer->base.ops = &tfile_write_ops;
writer->fp = NULL;
writer->pathname = NULL;
return (struct trace_file_writer *) writer;
}
/* target tfile command */
static tfile_target tfile_ops;
#define TRACE_HEADER_SIZE 8
#define TFILE_PID (1)
static char *trace_filename;
static int trace_fd = -1;
static off_t trace_frames_offset;
static off_t cur_offset;
static int cur_data_size;
int trace_regblock_size;
static struct buffer trace_tdesc;
static void tfile_append_tdesc_line (const char *line);
static void tfile_interp_line (char *line,
struct uploaded_tp **utpp,
struct uploaded_tsv **utsvp);
/* Read SIZE bytes into READBUF from the trace frame, starting at
TRACE_FD's current position. Note that this call `read'
underneath, hence it advances the file's seek position. Throws an
error if the `read' syscall fails, or less than SIZE bytes are
read. */
static void
tfile_read (gdb_byte *readbuf, int size)
{
int gotten;
gotten = read (trace_fd, readbuf, size);
if (gotten < 0)
perror_with_name (trace_filename);
else if (gotten < size)
error (_("Premature end of file while reading trace file"));
}
/* Open the tfile target. */
static void
tfile_target_open (const char *arg, int from_tty)
{
int flags;
int scratch_chan;
char header[TRACE_HEADER_SIZE];
char linebuf[1000]; /* Should be max remote packet size or so. */
gdb_byte byte;
int bytes, i;
struct trace_status *ts;
struct uploaded_tp *uploaded_tps = NULL;
struct uploaded_tsv *uploaded_tsvs = NULL;
target_preopen (from_tty);
if (!arg)
error (_("No trace file specified."));
gdb::unique_xmalloc_ptr<char> filename (tilde_expand (arg));
if (!IS_ABSOLUTE_PATH (filename.get ()))
filename = gdb_abspath (filename.get ());
flags = O_BINARY | O_LARGEFILE;
flags |= O_RDONLY;
scratch_chan = gdb_open_cloexec (filename.get (), flags, 0);
if (scratch_chan < 0)
perror_with_name (filename.get ());
/* Looks semi-reasonable. Toss the old trace file and work on the new. */
unpush_target (&tfile_ops);
trace_filename = filename.release ();
trace_fd = scratch_chan;
/* Make sure this is clear. */
buffer_free (&trace_tdesc);
bytes = 0;
/* Read the file header and test for validity. */
tfile_read ((gdb_byte *) &header, TRACE_HEADER_SIZE);
bytes += TRACE_HEADER_SIZE;
if (!(header[0] == 0x7f
&& (startswith (header + 1, "TRACE0\n"))))
error (_("File is not a valid trace file."));
push_target (&tfile_ops);
trace_regblock_size = 0;
ts = current_trace_status ();
/* We know we're working with a file. Record its name. */
ts->filename = trace_filename;
/* Set defaults in case there is no status line. */
ts->running_known = 0;
ts->stop_reason = trace_stop_reason_unknown;
ts->traceframe_count = -1;
ts->buffer_free = 0;
ts->disconnected_tracing = 0;
ts->circular_buffer = 0;
try
{
/* Read through a section of newline-terminated lines that
define things like tracepoints. */
i = 0;
while (1)
{
tfile_read (&byte, 1);
++bytes;
if (byte == '\n')
{
/* Empty line marks end of the definition section. */
if (i == 0)
break;
linebuf[i] = '\0';
i = 0;
tfile_interp_line (linebuf, &uploaded_tps, &uploaded_tsvs);
}
else
linebuf[i++] = byte;
if (i >= 1000)
error (_("Excessively long lines in trace file"));
}
/* By now, tdesc lines have been read from tfile - let's parse them. */
target_find_description ();
/* Record the starting offset of the binary trace data. */
trace_frames_offset = bytes;
/* If we don't have a blocksize, we can't interpret the
traceframes. */
if (trace_regblock_size == 0)
error (_("No register block size recorded in trace file"));
}
catch (const gdb_exception &ex)
{
/* Remove the partially set up target. */
unpush_target (&tfile_ops);
throw;
}
inferior_appeared (current_inferior (), TFILE_PID);
inferior_ptid = ptid_t (TFILE_PID);
add_thread_silent (&tfile_ops, inferior_ptid);
if (ts->traceframe_count <= 0)
warning (_("No traceframes present in this file."));
/* Add the file's tracepoints and variables into the current mix. */
/* Get trace state variables first, they may be checked when parsing
uploaded commands. */
merge_uploaded_trace_state_variables (&uploaded_tsvs);
merge_uploaded_tracepoints (&uploaded_tps);
post_create_inferior (&tfile_ops, from_tty);
}
/* Interpret the given line from the definitions part of the trace
file. */
static void
tfile_interp_line (char *line, struct uploaded_tp **utpp,
struct uploaded_tsv **utsvp)
{
char *p = line;
if (startswith (p, "R "))
{
p += strlen ("R ");
trace_regblock_size = strtol (p, &p, 16);
}
else if (startswith (p, "status "))
{
p += strlen ("status ");
parse_trace_status (p, current_trace_status ());
}
else if (startswith (p, "tp "))
{
p += strlen ("tp ");
parse_tracepoint_definition (p, utpp);
}
else if (startswith (p, "tsv "))
{
p += strlen ("tsv ");
parse_tsv_definition (p, utsvp);
}
else if (startswith (p, "tdesc "))
{
p += strlen ("tdesc ");
tfile_append_tdesc_line (p);
}
else
warning (_("Ignoring trace file definition \"%s\""), line);
}
/* Close the trace file and generally clean up. */
void
tfile_target::close ()
{
gdb_assert (trace_fd != -1);
inferior_ptid = null_ptid; /* Avoid confusion from thread stuff. */
exit_inferior_silent (current_inferior ());
::close (trace_fd);
trace_fd = -1;
xfree (trace_filename);
trace_filename = NULL;
buffer_free (&trace_tdesc);
trace_reset_local_state ();
}
void
tfile_target::files_info ()
{
printf_filtered ("\t`%s'\n", trace_filename);
}
void
tfile_target::get_tracepoint_status (struct breakpoint *tp, struct uploaded_tp *utp)
{
/* Other bits of trace status were collected as part of opening the
trace files, so nothing to do here. */
}
/* Given the position of a traceframe in the file, figure out what
address the frame was collected at. This would normally be the
value of a collected PC register, but if not available, we
improvise. */
static CORE_ADDR
tfile_get_traceframe_address (off_t tframe_offset)
{
CORE_ADDR addr = 0;
short tpnum;
struct tracepoint *tp;
off_t saved_offset = cur_offset;
/* FIXME dig pc out of collected registers. */
/* Fall back to using tracepoint address. */
lseek (trace_fd, tframe_offset, SEEK_SET);
tfile_read ((gdb_byte *) &tpnum, 2);
tpnum = (short) extract_signed_integer ((gdb_byte *) &tpnum, 2,
gdbarch_byte_order
(target_gdbarch ()));
tp = get_tracepoint_by_number_on_target (tpnum);
/* FIXME this is a poor heuristic if multiple locations. */
if (tp && tp->loc)
addr = tp->loc->address;
/* Restore our seek position. */
cur_offset = saved_offset;
lseek (trace_fd, cur_offset, SEEK_SET);
return addr;
}
/* Given a type of search and some parameters, scan the collection of
traceframes in the file looking for a match. When found, return
both the traceframe and tracepoint number, otherwise -1 for
each. */
int
tfile_target::trace_find (enum trace_find_type type, int num,
CORE_ADDR addr1, CORE_ADDR addr2, int *tpp)
{
short tpnum;
int tfnum = 0, found = 0;
unsigned int data_size;
struct tracepoint *tp;
off_t offset, tframe_offset;
CORE_ADDR tfaddr;
if (num == -1)
{
if (tpp)
*tpp = -1;
return -1;
}
lseek (trace_fd, trace_frames_offset, SEEK_SET);
offset = trace_frames_offset;
while (1)
{
tframe_offset = offset;
tfile_read ((gdb_byte *) &tpnum, 2);
tpnum = (short) extract_signed_integer ((gdb_byte *) &tpnum, 2,
gdbarch_byte_order
(target_gdbarch ()));
offset += 2;
if (tpnum == 0)
break;
tfile_read ((gdb_byte *) &data_size, 4);
data_size = (unsigned int) extract_unsigned_integer
((gdb_byte *) &data_size, 4,
gdbarch_byte_order (target_gdbarch ()));
offset += 4;
if (type == tfind_number)
{
/* Looking for a specific trace frame. */
if (tfnum == num)
found = 1;
}
else
{
/* Start from the _next_ trace frame. */
if (tfnum > get_traceframe_number ())
{
switch (type)
{
case tfind_pc:
tfaddr = tfile_get_traceframe_address (tframe_offset);
if (tfaddr == addr1)
found = 1;
break;
case tfind_tp:
tp = get_tracepoint (num);
if (tp && tpnum == tp->number_on_target)
found = 1;
break;
case tfind_range:
tfaddr = tfile_get_traceframe_address (tframe_offset);
if (addr1 <= tfaddr && tfaddr <= addr2)
found = 1;
break;
case tfind_outside:
tfaddr = tfile_get_traceframe_address (tframe_offset);
if (!(addr1 <= tfaddr && tfaddr <= addr2))
found = 1;
break;
default:
internal_error (__FILE__, __LINE__, _("unknown tfind type"));
}
}
}
if (found)
{
if (tpp)
*tpp = tpnum;
cur_offset = offset;
cur_data_size = data_size;
return tfnum;
}
/* Skip past the traceframe's data. */
lseek (trace_fd, data_size, SEEK_CUR);
offset += data_size;
/* Update our own count of traceframes. */
++tfnum;
}
/* Did not find what we were looking for. */
if (tpp)
*tpp = -1;
return -1;
}
/* Prototype of the callback passed to tframe_walk_blocks. */
typedef int (*walk_blocks_callback_func) (char blocktype, void *data);
/* Callback for traceframe_walk_blocks, used to find a given block
type in a traceframe. */
static int
match_blocktype (char blocktype, void *data)
{
char *wantedp = (char *) data;
if (*wantedp == blocktype)
return 1;
return 0;
}
/* Walk over all traceframe block starting at POS offset from
CUR_OFFSET, and call CALLBACK for each block found, passing in DATA
unmodified. If CALLBACK returns true, this returns the position in
the traceframe where the block is found, relative to the start of
the traceframe (cur_offset). Returns -1 if no callback call
returned true, indicating that all blocks have been walked. */
static int
traceframe_walk_blocks (walk_blocks_callback_func callback,
int pos, void *data)
{
/* Iterate through a traceframe's blocks, looking for a block of the
requested type. */
lseek (trace_fd, cur_offset + pos, SEEK_SET);
while (pos < cur_data_size)
{
unsigned short mlen;
char block_type;
tfile_read ((gdb_byte *) &block_type, 1);
++pos;
if ((*callback) (block_type, data))
return pos;
switch (block_type)
{
case 'R':
lseek (trace_fd, cur_offset + pos + trace_regblock_size, SEEK_SET);
pos += trace_regblock_size;
break;
case 'M':
lseek (trace_fd, cur_offset + pos + 8, SEEK_SET);
tfile_read ((gdb_byte *) &mlen, 2);
mlen = (unsigned short)
extract_unsigned_integer ((gdb_byte *) &mlen, 2,
gdbarch_byte_order
(target_gdbarch ()));
lseek (trace_fd, mlen, SEEK_CUR);
pos += (8 + 2 + mlen);
break;
case 'V':
lseek (trace_fd, cur_offset + pos + 4 + 8, SEEK_SET);
pos += (4 + 8);
break;
default:
error (_("Unknown block type '%c' (0x%x) in trace frame"),
block_type, block_type);
break;
}
}
return -1;
}
/* Convenience wrapper around traceframe_walk_blocks. Looks for the
position offset of a block of type TYPE_WANTED in the current trace
frame, starting at POS. Returns -1 if no such block was found. */
static int
traceframe_find_block_type (char type_wanted, int pos)
{
return traceframe_walk_blocks (match_blocktype, pos, &type_wanted);
}
/* Look for a block of saved registers in the traceframe, and get the
requested register from it. */
void
tfile_target::fetch_registers (struct regcache *regcache, int regno)
{
struct gdbarch *gdbarch = regcache->arch ();
int offset, regn, regsize, dummy;
/* An uninitialized reg size says we're not going to be
successful at getting register blocks. */
if (!trace_regblock_size)
return;
if (traceframe_find_block_type ('R', 0) >= 0)
{
gdb_byte *regs = (gdb_byte *) alloca (trace_regblock_size);
tfile_read (regs, trace_regblock_size);
for (regn = 0; regn < gdbarch_num_regs (gdbarch); regn++)
{
if (!remote_register_number_and_offset (regcache->arch (),
regn, &dummy, &offset))
continue;
regsize = register_size (gdbarch, regn);
/* Make sure we stay within block bounds. */
if (offset + regsize > trace_regblock_size)
break;
if (regcache->get_register_status (regn) == REG_UNKNOWN)
{
if (regno == regn)
{
regcache->raw_supply (regno, regs + offset);
break;
}
else if (regno == -1)
{
regcache->raw_supply (regn, regs + offset);
}
}
}
}
else
tracefile_fetch_registers (regcache, regno);
}
static enum target_xfer_status
tfile_xfer_partial_features (const char *annex,
gdb_byte *readbuf, const gdb_byte *writebuf,
ULONGEST offset, ULONGEST len,
ULONGEST *xfered_len)
{
if (strcmp (annex, "target.xml"))
return TARGET_XFER_E_IO;
if (readbuf == NULL)
error (_("tfile_xfer_partial: tdesc is read-only"));
if (trace_tdesc.used_size == 0)
return TARGET_XFER_E_IO;
if (offset >= trace_tdesc.used_size)
return TARGET_XFER_EOF;
if (len > trace_tdesc.used_size - offset)
len = trace_tdesc.used_size - offset;
memcpy (readbuf, trace_tdesc.buffer + offset, len);
*xfered_len = len;
return TARGET_XFER_OK;
}
enum target_xfer_status
tfile_target::xfer_partial (enum target_object object,
const char *annex, gdb_byte *readbuf,
const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
ULONGEST *xfered_len)
{
/* We're only doing regular memory and tdesc for now. */
if (object == TARGET_OBJECT_AVAILABLE_FEATURES)
return tfile_xfer_partial_features (annex, readbuf, writebuf,
offset, len, xfered_len);
if (object != TARGET_OBJECT_MEMORY)
return TARGET_XFER_E_IO;
if (readbuf == NULL)
error (_("tfile_xfer_partial: trace file is read-only"));
if (get_traceframe_number () != -1)
{
int pos = 0;
enum target_xfer_status res;
/* Records the lowest available address of all blocks that
intersects the requested range. */
ULONGEST low_addr_available = 0;
/* Iterate through the traceframe's blocks, looking for
memory. */
while ((pos = traceframe_find_block_type ('M', pos)) >= 0)
{
ULONGEST maddr, amt;
unsigned short mlen;
enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
tfile_read ((gdb_byte *) &maddr, 8);
maddr = extract_unsigned_integer ((gdb_byte *) &maddr, 8,
byte_order);
tfile_read ((gdb_byte *) &mlen, 2);
mlen = (unsigned short)
extract_unsigned_integer ((gdb_byte *) &mlen, 2, byte_order);
/* If the block includes the first part of the desired
range, return as much it has; GDB will re-request the
remainder, which might be in a different block of this
trace frame. */
if (maddr <= offset && offset < (maddr + mlen))
{
amt = (maddr + mlen) - offset;
if (amt > len)
amt = len;
if (maddr != offset)
lseek (trace_fd, offset - maddr, SEEK_CUR);
tfile_read (readbuf, amt);
*xfered_len = amt;
return TARGET_XFER_OK;
}
if (offset < maddr && maddr < (offset + len))
if (low_addr_available == 0 || low_addr_available > maddr)
low_addr_available = maddr;
/* Skip over this block. */
pos += (8 + 2 + mlen);
}
/* Requested memory is unavailable in the context of traceframes,
and this address falls within a read-only section, fallback
to reading from executable, up to LOW_ADDR_AVAILABLE. */
if (offset < low_addr_available)
len = std::min (len, low_addr_available - offset);
res = exec_read_partial_read_only (readbuf, offset, len, xfered_len);
if (res == TARGET_XFER_OK)
return TARGET_XFER_OK;
else
{
/* No use trying further, we know some memory starting
at MEMADDR isn't available. */
*xfered_len = len;
return TARGET_XFER_UNAVAILABLE;
}
}
else
{
/* Fallback to reading from read-only sections. */
return section_table_read_available_memory (readbuf, offset, len,
xfered_len);
}
}
/* Iterate through the blocks of a trace frame, looking for a 'V'
block with a matching tsv number. */
bool
tfile_target::get_trace_state_variable_value (int tsvnum, LONGEST *val)
{
int pos;
bool found = false;
/* Iterate over blocks in current frame and find the last 'V'
block in which tsv number is TSVNUM. In one trace frame, there
may be multiple 'V' blocks created for a given trace variable,
and the last matched 'V' block contains the updated value. */
pos = 0;
while ((pos = traceframe_find_block_type ('V', pos)) >= 0)
{
int vnum;
tfile_read ((gdb_byte *) &vnum, 4);
vnum = (int) extract_signed_integer ((gdb_byte *) &vnum, 4,
gdbarch_byte_order
(target_gdbarch ()));
if (tsvnum == vnum)
{
tfile_read ((gdb_byte *) val, 8);
*val = extract_signed_integer ((gdb_byte *) val, 8,
gdbarch_byte_order
(target_gdbarch ()));
found = true;
}
pos += (4 + 8);
}
return found;
}
/* Callback for traceframe_walk_blocks. Builds a traceframe_info
object for the tfile target's current traceframe. */
static int
build_traceframe_info (char blocktype, void *data)
{
struct traceframe_info *info = (struct traceframe_info *) data;
switch (blocktype)
{
case 'M':
{
ULONGEST maddr;
unsigned short mlen;
tfile_read ((gdb_byte *) &maddr, 8);
maddr = extract_unsigned_integer ((gdb_byte *) &maddr, 8,
gdbarch_byte_order
(target_gdbarch ()));
tfile_read ((gdb_byte *) &mlen, 2);
mlen = (unsigned short)
extract_unsigned_integer ((gdb_byte *) &mlen,
2, gdbarch_byte_order
(target_gdbarch ()));
info->memory.emplace_back (maddr, mlen);
break;
}
case 'V':
{
int vnum;
tfile_read ((gdb_byte *) &vnum, 4);
info->tvars.push_back (vnum);
}
case 'R':
case 'S':
{
break;
}
default:
warning (_("Unhandled trace block type (%d) '%c ' "
"while building trace frame info."),
blocktype, blocktype);
break;
}
return 0;
}
traceframe_info_up
tfile_target::traceframe_info ()
{
traceframe_info_up info (new struct traceframe_info);
traceframe_walk_blocks (build_traceframe_info, 0, info.get ());
return info;
}
/* Handles tdesc lines from tfile by appending the payload to
a global trace_tdesc variable. */
static void
tfile_append_tdesc_line (const char *line)
{
buffer_grow_str (&trace_tdesc, line);
buffer_grow_str (&trace_tdesc, "\n");
}
void
_initialize_tracefile_tfile (void)
{
add_target (tfile_target_info, tfile_target_open, filename_completer);
}
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