gdb/gdbserver/

2010-06-01  Pedro Alves  <pedro@codesourcery.com>
	    Stan Shebs  <stan@codesourcery.com>

	* Makefile.in (IPA_DEPFILES, extra_libraries): New.
	(all): Depend on $(extra_libraries).
	(install-only): Install the IPA.
	(IPA_OBJS, IPA_LIB): New.
	(clean): Remove the IPA lib.
	(IPAGENT_CFLAGS): New.
	(tracepoint-ipa.o, utils-ipa.o, remote-utils-ipa.o)
	(regcache-ipa.o, i386-linux-ipa.o, linux-i386-ipa.o)
	(linux-amd64-ipa.o, amd64-linux-ipa.o): New rules.
	* linux-amd64-ipa.c, linux-i386-ipa.c: New files.
	* configure.ac: Check for atomic builtins support in the compiler.
	(IPA_DEPFILES, extra_libraries): Define.
	* configure.srv (ipa_obj): Add description.
	(ipa_i386_linux_regobj, ipa_amd64_linux_regobj): Define.
	(i[34567]86-*-linux*): Set ipa_obj.
	(x86_64-*-linux*): Set ipa_obj.
	* linux-low.c (stabilizing_threads): New.
	(supports_fast_tracepoints): New.
	(linux_detach): Stabilize threads before detaching.
	(handle_tracepoints): Handle internal tracing breakpoints.  Assert
	the lwp is either not stabilizing, or is moving out of a jump pad.
	(linux_fast_tracepoint_collecting): New.
	(maybe_move_out_of_jump_pad): New.
	(enqueue_one_deferred_signal): New.
	(dequeue_one_deferred_signal): New.
	(linux_wait_for_event_1): If moving out of a jump pad, defer
	pending signals to later.
	(linux_stabilize_threads): New.
	(linux_wait_1): Check if threads need moving out of jump pads, and
	do it if so.
	(stuck_in_jump_pad_callback): New.
	(move_out_of_jump_pad_callback): New.
	(lwp_running): New.
	(linux_resume_one_lwp): Handle moving out of jump pads.
	(linux_set_resume_request): Dequeue deferred signals.
	(need_step_over_p): Also step over fast tracepoint jumps.
	(start_step_over): Also uninsert fast tracepoint jumps.
	(finish_step_over): Also reinsert fast tracepoint jumps.
	(linux_install_fast_tracepoint_jump): New.
	(linux_target_ops): Install linux_stabilize_threads and
	linux_install_fast_tracepoint_jump_pad.
	* linux-low.h (linux_target_ops) <get_thread_area,
	install_fast_tracepoint_jump_pad>: New fields.
	(struct lwp_info) <collecting_fast_tracepoint,
	pending_signals_to_report, exit_jump_pad_bkpt>: New fields.
	(linux_get_thread_area): Declare.
	* linux-x86-low.c (jump_insn): New.
	(x86_get_thread_area): New.
	(append_insns): New.
	(push_opcode): New.
	(amd64_install_fast_tracepoint_jump_pad): New.
	(i386_install_fast_tracepoint_jump_pad): New.
	(x86_install_fast_tracepoint_jump_pad): New.
	(the_low_target): Install x86_get_thread_area and
	x86_install_fast_tracepoint_jump_pad.
	* mem-break.c (set_raw_breakpoint_at): Use read_inferior_memory.
	(struct fast_tracepoint_jump): New.
	(fast_tracepoint_jump_insn): New.
	(fast_tracepoint_jump_shadow): New.
	(find_fast_tracepoint_jump_at): New.
	(fast_tracepoint_jump_here): New.
	(delete_fast_tracepoint_jump): New.
	(set_fast_tracepoint_jump): New.
	(uninsert_fast_tracepoint_jumps_at): New.
	(reinsert_fast_tracepoint_jumps_at): New.
	(set_breakpoint_at): Use write_inferior_memory.
	(uninsert_raw_breakpoint): Use write_inferior_memory.
	(check_mem_read): Mask out fast tracepoint jumps.
	(check_mem_write): Mask out fast tracepoint jumps.
	* mem-break.h (struct fast_tracepoint_jump): Forward declare.
	(set_fast_tracepoint_jump): Declare.
	(delete_fast_tracepoint_jump)
	(fast_tracepoint_jump_here, uninsert_fast_tracepoint_jumps_at)
	(reinsert_fast_tracepoint_jumps_at): Declare.
	* regcache.c: Don't compile many functions when building the
	in-process agent library.
	(init_register_cache) [IN_PROCESS_AGENT]: Don't allow allocating
	the register buffer in the heap.
	(free_register_cache): If the register buffer isn't owned by the
	regcache, don't free it.
	(set_register_cache) [IN_PROCESS_AGENT]: Don't re-alocate
	pre-existing register caches.
	* remote-utils.c (convert_int_to_ascii): Constify `from' parameter
	type.
	(convert_ascii_to_int): : Constify `from' parameter type.
	(decode_M_packet, decode_X_packet): Replace the `to' parameter by
	a `to_p' pointer to pointer parameter.  If TO_P is NULL, malloc
	the needed buffer in-place.
	(relocate_instruction): New.
	* server.c (handle_query) <qSymbols>: If the target supports
	tracepoints, give it a chance of looking up symbols.  Report
	support for fast tracepoints.
	(handle_status): Stabilize threads.
	(process_serial_event): Adjust.
	* server.h (struct fast_tracepoint_jump): Forward declare.
	(struct process_info) <fast_tracepoint_jumps>: New field.
	(convert_ascii_to_int, convert_int_to_ascii): Adjust.
	(decode_X_packet, decode_M_packet): Adjust.
	(relocate_instruction): Declare.
	(in_process_agent_loaded): Declare.
	(tracepoint_look_up_symbols): Declare.
	(struct fast_tpoint_collect_status): Declare.
	(fast_tracepoint_collecting): Declare.
	(force_unlock_trace_buffer): Declare.
	(handle_tracepoint_bkpts): Declare.
	(initialize_low_tracepoint)
	(supply_fast_tracepoint_registers) [IN_PROCESS_AGENT]: Declare.
	* target.h (struct target_ops) <stabilize_threads,
	install_fast_tracepoint_jump_pad>: New fields.
	(stabilize_threads, install_fast_tracepoint_jump_pad): New.
	* tracepoint.c [HAVE_MALLOC_H]: Include malloc.h.
	[HAVE_STDINT_H]: Include stdint.h.
	(trace_debug_1): Rename to ...
	(trace_vdebug): ... this.
	(trace_debug): Rename to ...
	(trace_debug_1): ... this.  Add `level' parameter.
	(trace_debug): New.
	(ATTR_USED, ATTR_NOINLINE): New.
	(IP_AGENT_EXPORT): New.
	(gdb_tp_heap_buffer, gdb_jump_pad_buffer, gdb_jump_pad_buffer_end)
	(collecting, gdb_collect, stop_tracing, flush_trace_buffer)
	(about_to_request_buffer_space, trace_buffer_is_full)
	(stopping_tracepoint, expr_eval_result, error_tracepoint)
	(tracepoints, tracing, trace_buffer_ctrl, trace_buffer_ctrl_curr)
	(trace_buffer_lo, trace_buffer_hi, traceframe_read_count)
	(traceframe_write_count, traceframes_created)
	(trace_state_variables)
	New renaming defines.
	(struct ipa_sym_addresses): New.
	(STRINGIZE_1, STRINGIZE, IPA_SYM): New.
	(symbol_list): New.
	(ipa_sym_addrs): New.
	(all_tracepoint_symbols_looked_up): New.
	(in_process_agent_loaded): New.
	(write_e_ipa_not_loaded): New.
	(maybe_write_ipa_not_loaded): New.
	(tracepoint_look_up_symbols): New.
	(debug_threads) [IN_PROCESS_AGENT]: New.
	(read_inferior_memory) [IN_PROCESS_AGENT]: New.
	(UNKNOWN_SIDE_EFFECTS): New.
	(stop_tracing): New.
	(flush_trace_buffer): New.
	(stop_tracing_bkpt): New.
	(flush_trace_buffer_bkpt): New.
	(read_inferior_integer): New.
	(read_inferior_uinteger): New.
	(read_inferior_data_pointer): New.
	(write_inferior_data_pointer): New.
	(write_inferior_integer): New.
	(write_inferior_uinteger): New.
	(struct collect_static_trace_data_action): Delete.
	(enum tracepoint_type): New.
	(struct tracepoint) <type>: New field `type'.
	<actions_str, step_actions, step_actions_str>: Only include in GDBserver.
	<orig_size, obj_addr_on_target, adjusted_insn_addr>
	<adjusted_insn_addr_end, jump_pad, jump_pad_end>: New fields.
	(tracepoints): Use IP_AGENT_EXPORT.
	(last_tracepoint): Don't include in the IPA.
	(stopping_tracepoint): Use IP_AGENT_EXPORT.
	(trace_buffer_is_full): Use IP_AGENT_EXPORT.
	(alloced_trace_state_variables): New.
	(trace_state_variables): Use IP_AGENT_EXPORT.
	(traceframe_t): Delete unused variable.
	(circular_trace_buffer): Don't include in the IPA.
	(trace_buffer_start): Delete.
	(struct trace_buffer_control): New.
	(trace_buffer_free): Delete.
	(struct ipa_trace_buffer_control): New.
	(GDBSERVER_FLUSH_COUNT_MASK, GDBSERVER_FLUSH_COUNT_MASK_PREV)
	(GDBSERVER_FLUSH_COUNT_MASK_CURR, GDBSERVER_UPDATED_FLUSH_COUNT_BIT):
	New.
	(trace_buffer_ctrl): New.
	(TRACE_BUFFER_CTRL_CURR): New.
	(trace_buffer_start, trace_buffer_free, trace_buffer_end_free):
	Reimplement as macros.
	(trace_buffer_wrap): Delete.
	(traceframe_write_count, traceframe_read_count)
	(traceframes_created, tracing): Use IP_AGENT_EXPORT.
	(struct tracepoint_hit_ctx) <type>: New field.
	(struct fast_tracepoint_ctx): New.
	(memory_barrier): New.
	(cmpxchg): New.
	(record_tracepoint_error): Update atomically in the IPA.
	(clear_inferior_trace_buffer): New.
	(about_to_request_buffer_space): New.
	(trace_buffer_alloc): Handle GDBserver and inferior simulatenous
	updating the same buffer.
	(add_tracepoint): Default the tracepoint's type to trap
	tracepoint, and orig_size to -1.
	(get_trace_state_variable) [IN_PROCESS_AGENT]: Handle allocated
	internal variables.
	(create_trace_state_variable): New parameter `gdb'.  Handle it.
	(clear_installed_tracepoints): Clear fast tracepoint jumps.
	(cmd_qtdp): Handle fast tracepoints.
	(cmd_qtdv): Adjust.
	(max_jump_pad_size): New.
	(gdb_jump_pad_head): New.
	(get_jump_space_head): New.
	(claim_jump_space): New.
	(sort_tracepoints): New.
	(MAX_JUMP_SIZE): New.
	(cmd_qtstart): Handle fast tracepoints.  Sync tracepoints with the
	IPA.
	(stop_tracing) [IN_PROCESS_AGENT]: Don't include the tdisconnected
	support.  Upload fast traceframes, and delete internal IPA
	breakpoints.
	(stop_tracing_handler): New.
	(flush_trace_buffer_handler): New.
	(cmd_qtstop): Upload fast tracepoints.
	(response_tracepoint): Handle fast tracepoints.
	(tracepoint_finished_step): Upload fast traceframes.  Set the
	tracepoint hit context's tracepoint type.
	(handle_tracepoint_bkpts): New.
	(tracepoint_was_hit): Set the tracepoint hit context's tracepoint
	type.  Add comment about fast tracepoints.
	(collect_data_at_tracepoint) [IN_PROCESS_AGENT]: Don't access the
	non-existing action_str field.
	(get_context_regcache): Handle fast tracepoints.
	(do_action_at_tracepoint) [!IN_PROCESS_AGENT]: Don't write the PC
	to the regcache.
	(fast_tracepoint_from_jump_pad_address): New.
	(fast_tracepoint_from_ipa_tpoint_address): New.
	(collecting_t): New.
	(force_unlock_trace_buffer): New.
	(fast_tracepoint_collecting): New.
	(collecting): New.
	(gdb_collect): New.
	(write_inferior_data_ptr): New.
	(target_tp_heap): New.
	(target_malloc): New.
	(download_agent_expr): New.
	(UALIGN): New.
	(download_tracepoints): New.
	(download_trace_state_variables): New.
	(upload_fast_traceframes): New.
	(IPA_FIRST_TRACEFRAME): New.
	(IPA_NEXT_TRACEFRAME_1): New.
	(IPA_NEXT_TRACEFRAME): New.
	[IN_PROCESS_AGENT]: Include sys/mman.h and fcntl.h.
	[IN_PROCESS_AGENT] (gdb_tp_heap_buffer, gdb_jump_pad_buffer)
	(gdb_jump_pad_buffer_end): New.
	[IN_PROCESS_AGENT] (initialize_tracepoint_ftlib): New.
	(initialize_tracepoint): Adjust.
	[IN_PROCESS_AGENT]: Allocate the IPA heap, and jump pad scratch
	buffer.  Initialize the low module.
	* utils.c (PREFIX, TOOLNAME): New.
	(malloc_failure): Use PREFIX.
	(error): In the IPA, an error causes an exit.
	(fatal, warning): Use PREFIX.
	(internal_error): Use TOOLNAME.
	(NUMCELLS): Increase to 10.
	* configure, config.in: Regenerate.

gdb/
2010-06-01  Pedro Alves  <pedro@codesourcery.com>

	* NEWS: Mention gdbserver fast tracepoints support.

gdb/doc/
2010-06-01  Pedro Alves  <pedro@codesourcery.com>

	* gdb.texinfo (Set Tracepoints): Mention tracepoints support in
	gdbserver, and add cross reference.
	(Tracepoints support in gdbserver): New subsection.

2 files changed, 85 insertions, 0 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index d5b7f1c..4ffe455 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,9 @@
+2010-06-01  Pedro Alves  <pedro@codesourcery.com>
+
+	* gdb.texinfo (Set Tracepoints): Mention tracepoints support in
+	gdbserver, and add cross reference.
+	(Tracepoints support in gdbserver): New subsection.
+
 2010-05-26  Pedro Alves  <pedro@codesourcery.com>
 
 	* gdb.texinfo (General Query Packets) <qSupported>: Describe the
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 72c86e9..178ef68 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -9440,6 +9440,9 @@ Some targets may support @dfn{fast tracepoints}, which are inserted in
 a different way (such as with a jump instead of a trap), that is
 faster but possibly restricted in where they may be installed.
 
+@code{gdbserver} supports tracepoints on some target systems.
+@xref{Server,,Tracepoints support in @code{gdbserver}}.
+
 This section describes commands to set tracepoints and associated
 conditions and actions.
 
@@ -15692,6 +15695,82 @@ of a multi-process mode debug session.
 
 @end table
 
+@subsection Tracepoints support in @code{gdbserver}
+@cindex tracepoints support in @code{gdbserver}
+
+On some targets, @code{gdbserver} supports tracepoints and fast
+tracepoints.
+
+For fast tracepoints to work, a special library called the
+@dfn{in-process agent} (IPA), must be loaded in the inferior process.
+This library is built and distributed as an integral part of
+@code{gdbserver}.
+
+There are several ways to load the in-process agent in your program:
+
+@table @code
+@item Specifying it as dependency at link time
+
+You can link your program dynamically with the in-process agent
+library.  On most systems, this is accomplished by adding
+@code{-linproctrace} to the link command.
+
+@item Using the system's preloading mechanisms
+
+You can force loading the in-process agent at startup time by using
+your system's support for preloading shared libraries.  Many Unixes
+support the concept of preloading user defined libraries.  In most
+cases, you do that by specifying @code{LD_PRELOAD=libinproctrace.so}
+in the environment.  See also the description of @code{gdbserver}'s
+@option{--wrapper} command line option.
+
+@item Using @value{GDBN} to force loading the agent at run time
+
+On some systems, you can force the inferior to load a shared library,
+by calling a dynamic loader function in the inferior that takes care
+of dynamically looking up and loading a shared library.  On most Unix
+systems, the function is @code{dlopen}.  You'll use the @code{call}
+command for that.  For example:
+
+@smallexample
+(@value{GDBP}) call dlopen ("libinproctrace.so", ...)
+@end smallexample
+
+Note that on most Unix systems, for the @code{dlopen} function to be
+available, the program needs to be linked with @code{-ldl}.
+@end table
+
+On systems that have a userspace dynamic loader, like most Unix
+systems, when you connect to @code{gdbserver} using @code{target
+remote}, you'll find that the program is stopped at the dynamic
+loader's entry point, and no shared library has been loaded in the
+program's address space yet, including the in-process agent.  In that
+case, before being able to use any of the fast tracepoints features,
+you need to let the loader run and load the shared libraries.  The
+most simple way to do that is to run the program to the main
+procedure.  E.g., if debugging a C or C@t{++} program, start
+@code{gdbserver} like so:
+
+@smallexample
+$ gdbserver :9999 myprogram
+@end smallexample
+
+Start GDB and connect to @code{gdbserver} like so, and run to main:
+
+@smallexample
+$ gdb myprogram
+(@value{GDBP}) target remote myhost:9999
+0x00007f215893ba60 in ?? () from /lib64/ld-linux-x86-64.so.2
+(@value{GDBP}) b main
+(@value{GDBP}) continue
+@end smallexample
+
+The in-process tracing agent library should now be loaded into the
+process; you can confirm it with the @code{info sharedlibrary}
+command, which will list @file{libinproctrace.so} as loaded in the
+process.  You are now ready to install fast tracepoints and start
+tracing.
+
 @node Remote Configuration
 @section Remote Configuration