This patch implements support for exec events on extended-remote Linux
targets. Follow-exec-mode and rerun behave as expected. Catchpoints and
test updates are implemented in subsequent patches.
This patch was derived from a patch posted last October:
https://sourceware.org/ml/gdb-patches/2014-10/msg00877.html.
It was originally based on some work done by Luis Machado in 2013.
IMPLEMENTATION
----------------
Exec events are enabled via ptrace options.
When an exec event is detected by gdbserver, the existing process
data, along with all its associated lwp and thread data, is deleted
and replaced by data for a new single-threaded process. The new
process data is initialized with the appropriate parts of the state
of the execing process. This approach takes care of several potential
pitfalls, including:
* deleting the data for an execing non-leader thread before any
wait/sigsuspend occurs
* correctly initializing the architecture of the execed process
We then report the exec event using a new RSP stop reason, "exec".
When GDB receives an "exec" event, it saves the status in the event
structure's target_waitstatus field, like what is done for remote fork
events. Because the original and execed programs may have different
architectures, we skip parsing the section of the stop reply packet
that contains register data. The register data will be retrieved
later after the inferior's architecture has been set up by
infrun.c:follow_exec.
At that point the exec event is handled by the existing event handling
in GDB. However, a few changes were necessary so that
infrun.c:follow_exec could accommodate the remote target.
* Where follow-exec-mode "new" is handled, we now call
add_inferior_with_spaces instead of add_inferior with separate calls
to set up the program and address spaces. The motivation for this
is that add_inferior_with_spaces also sets up the initial architecture
for the inferior, which is needed later by target_find_description
when it calls target_gdbarch.
* We call a new target function, target_follow_exec. This function
allows us to store the execd_pathname in the inferior, instead of
using the static string remote_exec_file from remote.c. The static
string didn't work for follow-exec-mode "new", since once you switched
to the execed program, the original remote exec-file was lost. The
execd_pathname is now stored in the inferior's program space as a
REGISTRY field. All of the requisite mechanisms for this are
defined in remote.c.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_mourn): Static declaration.
(linux_arch_setup): Move in front of
handle_extended_wait.
(linux_arch_setup_thread): New function.
(handle_extended_wait): Handle exec events. Call
linux_arch_setup_thread. Make event_lwp argument a
pointer-to-a-pointer.
(check_zombie_leaders): Do not check stopped threads.
(linux_low_ptrace_options): Add PTRACE_O_TRACEEXEC.
(linux_low_filter_event): Add lwp and thread for exec'ing
non-leader thread if leader thread has been deleted.
Refactor code into linux_arch_setup_thread and call it.
Pass child lwp pointer by reference to handle_extended_wait.
(linux_wait_for_event_filtered): Update comment.
(linux_wait_1): Prevent clobbering exec event status.
(linux_supports_exec_events): New function.
(linux_target_ops) <supports_exec_events>: Initialize new member.
* lynx-low.c (lynx_target_ops) <supports_exec_events>: Initialize
new member.
* remote-utils.c (prepare_resume_reply): New stop reason 'exec'.
* server.c (report_exec_events): New global variable.
(handle_query): Handle qSupported query for exec-events feature.
(captured_main): Initialize report_exec_events.
* server.h (report_exec_events): Declare new global variable.
* target.h (struct target_ops) <supports_exec_events>: New
member.
(target_supports_exec_events): New macro.
* win32-low.c (win32_target_ops) <supports_exec_events>:
Initialize new member.
gdb/ChangeLog:
* infrun.c (follow_exec): Use process-style ptid for
exec message. Call add_inferior_with_spaces and
target_follow_exec.
* nat/linux-ptrace.c (linux_supports_traceexec): New function.
* nat/linux-ptrace.h (linux_supports_traceexec): Declare.
* remote.c (remote_pspace_data): New static variable.
(remote_pspace_data_cleanup): New function.
(get_remote_exec_file): New function.
(set_remote_exec_file_1): New function.
(set_remote_exec_file): New function.
(show_remote_exec_file): New function.
(remote_exec_file): Delete static variable.
(anonymous enum) <PACKET_exec_event_feature> New
enumeration constant.
(remote_protocol_features): Add entry for exec-events feature.
(remote_query_supported): Add client side of qSupported query
for exec-events feature.
(remote_follow_exec): New function.
(remote_parse_stop_reply): Handle 'exec' stop reason.
(extended_remote_run, extended_remote_create_inferior): Call
get_remote_exec_file and set_remote_exec_file_1.
(init_extended_remote_ops) <to_follow_exec>: Initialize new
member.
(_initialize_remote): Call
register_program_space_data_with_cleanup. Call
add_packet_config_cmd for remote exec-events feature.
Modify call to add_setshow_string_noescape_cmd for exec-file
to use new functions set_remote_exec_file and
show_remote_exec_file.
* target-debug.h, target-delegates.c: Regenerated.
* target.c (target_follow_exec): New function.
* target.h (struct target_ops) <to_follow_exec>: New member.
(target_follow_exec): Declare new function.
This patch is mostly extracted from Pedro's C++ branch. It adds explicit
casts from integer to enum types, where it is really the intention to do
so. This could be because we are ...
* iterating on enum values (we need to iterate on an equivalent integer)
* converting from a value read from bytes (dwarf attribute, agent
expression opcode) to the equivalent enum
* reading the equivalent integer value from another language (Python/Guile)
An exception to that is the casts in regcache.c. It seems to me like
struct regcache's register_status field could be a pointer to an array of
enum register_status. Doing so would waste a bit of memory (4 bytes
used by the enum vs 1 byte used by the current signed char, for each
register). If we switch to C++11 one day, we can define the underlying
type of an enum type, so we could have the best of both worlds.
gdb/ChangeLog:
* arm-tdep.c (set_fp_model_sfunc): Add cast from integer to enum.
(arm_set_abi): Likewise.
* ax-general.c (ax_print): Likewise.
* c-exp.y (exp : string_exp): Likewise.
* compile/compile-loc2c.c (compute_stack_depth_worker): Likewise.
(do_compile_dwarf_expr_to_c): Likewise.
* cp-name-parser.y (demangler_special : DEMANGLER_SPECIAL start):
Likewise.
* dwarf2expr.c (execute_stack_op): Likewise.
* dwarf2loc.c (dwarf2_compile_expr_to_ax): Likewise.
(disassemble_dwarf_expression): Likewise.
* dwarf2read.c (dwarf2_add_member_fn): Likewise.
(read_array_order): Likewise.
(abbrev_table_read_table): Likewise.
(read_attribute_value): Likewise.
(skip_unknown_opcode): Likewise.
(dwarf_decode_macro_bytes): Likewise.
(dwarf_decode_macros): Likewise.
* eval.c (value_f90_subarray): Likewise.
* guile/scm-param.c (gdbscm_make_parameter): Likewise.
* i386-linux-tdep.c (i386_canonicalize_syscall): Likewise.
* infrun.c (handle_command): Likewise.
* memory-map.c (memory_map_start_memory): Likewise.
* osabi.c (set_osabi): Likewise.
* parse.c (operator_length_standard): Likewise.
* ppc-linux-tdep.c (ppc_canonicalize_syscall): Likewise, and use
single return point.
* python/py-frame.c (gdbpy_frame_stop_reason_string): Likewise.
* python/py-symbol.c (gdbpy_lookup_symbol): Likewise.
(gdbpy_lookup_global_symbol): Likewise.
* record-full.c (record_full_restore): Likewise.
* regcache.c (regcache_register_status): Likewise.
(regcache_raw_read): Likewise.
(regcache_cooked_read): Likewise.
* rs6000-tdep.c (powerpc_set_vector_abi): Likewise.
* symtab.c (initialize_ordinary_address_classes): Likewise.
* target-debug.h (target_debug_print_signals): Likewise.
* utils.c (do_restore_current_language): Likewise.
Add a struct to describe the branch trace configuration and use it for
enabling branch tracing.
The user will be able to set configuration fields for each tracing format
to be used for new threads.
The actual configuration that is active for a given thread will be shown
in the "info record" command.
At the moment, the configuration struct only contains a format field
that is set to the only available format.
The format is the only configuration option that can not be set via set
commands. It is given as argument to the "record btrace" command when
starting recording.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* Makefile.in (XMLFILES): Add btrace-conf.dtd.
* x86-linux-nat.c (x86_linux_enable_btrace): Update parameters.
(x86_linux_btrace_conf): New.
(x86_linux_create_target): Initialize to_btrace_conf.
* nat/linux-btrace.c (linux_enable_btrace): Update parameters.
Check format. Split into this and ...
(linux_enable_bts): ... this.
(linux_btrace_conf): New.
(perf_event_skip_record): Renamed into ...
(perf_event_skip_bts_record): ... this. Updated users.
(linux_disable_btrace): Split into this and ...
(linux_disable_bts): ... this.
(linux_read_btrace): Check format.
* nat/linux-btrace.h (linux_enable_btrace): Update parameters.
(linux_btrace_conf): New.
(btrace_target_info)<ptid>: Moved.
(btrace_target_info)<conf>: New.
(btrace_target_info): Split into this and ...
(btrace_tinfo_bts): ... this. Updated users.
* btrace.c (btrace_enable): Update parameters.
(btrace_conf, parse_xml_btrace_conf_bts, parse_xml_btrace_conf)
(btrace_conf_children, btrace_conf_attributes)
(btrace_conf_elements): New.
* btrace.h (btrace_enable): Update parameters.
(btrace_conf, parse_xml_btrace_conf): New.
* common/btrace-common.h (btrace_config): New.
* feature/btrace-conf.dtd: New.
* record-btrace.c (record_btrace_conf): New.
(record_btrace_cmdlist): New.
(record_btrace_enable_warn, record_btrace_open): Pass
&record_btrace_conf.
(record_btrace_info): Print recording format.
(cmd_record_btrace_bts_start): New.
(cmd_record_btrace_start): Call cmd_record_btrace_bts_start.
(_initialize_record_btrace): Add "record btrace bts" subcommand.
Add "record bts" alias command.
* remote.c (remote_state)<btrace_config>: New.
(remote_btrace_reset, PACKET_qXfer_btrace_conf): New.
(remote_protocol_features): Add qXfer:btrace-conf:read.
(remote_open_1): Call remote_btrace_reset.
(remote_xfer_partial): Handle TARGET_OBJECT_BTRACE_CONF.
(btrace_target_info)<conf>: New.
(btrace_sync_conf, btrace_read_config): New.
(remote_enable_btrace): Update parameters. Call btrace_sync_conf and
btrace_read_conf.
(remote_btrace_conf): New.
(init_remote_ops): Initialize to_btrace_conf.
(_initialize_remote): Add qXfer:btrace-conf packet.
* target.c (target_enable_btrace): Update parameters.
(target_btrace_conf): New.
* target.h (target_enable_btrace): Update parameters.
(target_btrace_conf): New.
(target_object)<TARGET_OBJECT_BTRACE_CONF>: New.
(target_ops)<to_enable_btrace>: Update parameters and comment.
(target_ops)<to_btrace_conf>: New.
* target-delegates: Regenerate.
* target-debug.h (target_debug_print_const_struct_btrace_config_p)
(target_debug_print_const_struct_btrace_target_info_p): New.
NEWS: Announce new command and new packet.
doc/
* gdb.texinfo (Process Record and Replay): Describe the "record
btrace bts" command.
(General Query Packets): Describe qXfer:btrace-conf:read packet.
(Branch Trace Configuration Format): New.
gdbserver/
* linux-low.c (linux_low_enable_btrace): Update parameters.
(linux_low_btrace_conf): New.
(linux_target_ops)<to_btrace_conf>: Initialize.
* server.c (current_btrace_conf): New.
(handle_btrace_enable): Rename to ...
(handle_btrace_enable_bts): ... this. Pass ¤t_btrace_conf
to target_enable_btrace. Update comment. Update users.
(handle_qxfer_btrace_conf): New.
(qxfer_packets): Add btrace-conf entry.
(handle_query): Report qXfer:btrace-conf:read as supported packet.
* target.h (target_ops)<enable_btrace>: Update parameters and comment.
(target_ops)<read_btrace_conf>: New.
(target_enable_btrace): Update parameters.
(target_read_btrace_conf): New.
testsuite/
* gdb.btrace/delta.exp: Update "info record" output.
* gdb.btrace/enable.exp: Update "info record" output.
* gdb.btrace/finish.exp: Update "info record" output.
* gdb.btrace/instruction_history.exp: Update "info record" output.
* gdb.btrace/next.exp: Update "info record" output.
* gdb.btrace/nexti.exp: Update "info record" output.
* gdb.btrace/step.exp: Update "info record" output.
* gdb.btrace/stepi.exp: Update "info record" output.
* gdb.btrace/nohist.exp: Update "info record" output.
Add a format argument to the various supports_btrace functions to check
for support of a specific btrace format. This is to prepare for a new
format.
Removed two redundant calls. The check will be made in the subsequent
btrace_enable call.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* btrace.c (btrace_enable): Pass BTRACE_FORMAT_BTS.
* record-btrace.c (record_btrace_open): Remove call to
target_supports_btrace.
* remote.c (remote_supports_btrace): Update parameters.
* target.c (target_supports_btrace): Update parameters.
* target.h (to_supports_btrace, target_supports_btrace): Update
parameters.
* target-delegates.c: Regenerate.
* target-debug.h (target_debug_print_enum_btrace_format): New.
* nat/linux-btrace.c
(kernel_supports_btrace): Rename into ...
(kernel_supports_bts): ... this. Update users. Update warning text.
(intel_supports_btrace): Rename into ...
(intel_supports_bts): ... this. Update users.
(cpu_supports_btrace): Rename into ...
(cpu_supports_bts): ... this. Update users.
(linux_supports_btrace): Update parameters. Split into this and ...
(linux_supports_bts): ... this.
* nat/linux-btrace.h (linux_supports_btrace): Update parameters.
gdbserver/
* server.c (handle_btrace_general_set): Remove call to
target_supports_btrace.
(supported_btrace_packets): New.
(handle_query): Call supported_btrace_packets.
* target.h: include btrace-common.h.
(btrace_target_info): Removed.
(supports_btrace, target_supports_btrace): Update parameters.
Add a structure to hold the branch trace data and an enum to describe
the format of that data. So far, only BTS is supported. Also added
a NONE format to indicate that no branch trace data is available.
This will make it easier to support different branch trace formats in
the future.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* Makefile.in (SFILES): Add common/btrace-common.c.
(COMMON_OBS): Add common/btrace-common.o.
(btrace-common.o): Add build rules.
* btrace.c (parse_xml_btrace): Update parameters.
(parse_xml_btrace_block): Set format field.
(btrace_add_pc, btrace_fetch): Use struct btrace_data.
(do_btrace_data_cleanup, make_cleanup_btrace_data): New.
(btrace_compute_ftrace): Split into this and...
(btrace_compute_ftrace_bts): ...this.
(btrace_stitch_trace): Split into this and...
(btrace_stitch_bts): ...this.
* btrace.h (parse_xml_btrace): Update parameters.
(make_cleanup_btrace_data): New.
* common/btrace-common.c: New.
* common/btrace-common.h: Include common-defs.h.
(btrace_block_s): Update comment.
(btrace_format): New.
(btrace_format_string): New.
(btrace_data_bts): New.
(btrace_data): New.
(btrace_data_init, btrace_data_fini, btrace_data_empty): New.
* remote.c (remote_read_btrace): Update parameters.
* target.c (target_read_btrace): Update parameters.
* target.h (target_read_btrace): Update parameters.
(target_ops)<to_read_btrace>: Update parameters.
* x86-linux-nat.c (x86_linux_read_btrace): Update parameters.
* target-delegates.c: Regenerate.
* target-debug (target_debug_print_struct_btrace_data_p): New.
* nat/linux-btrace.c (linux_read_btrace): Split into this and...
(linux_read_bts): ...this.
* nat/linux-btrace.h (linux_read_btrace): Update parameters.
gdbserver/
* Makefile.in (SFILES): Add common/btrace-common.c.
(OBS): Add common/btrace-common.o.
(btrace-common.o): Add build rules.
* linux-low: Include btrace-common.h.
(linux_low_read_btrace): Use struct btrace_data. Call
btrace_data_init and btrace_data_fini.
The target debug methods are inconsistently maintained. Most to_*
methods have some kind of targetdebug awareness, but not all of them
do. The ones that do vary in the quantity and quality of output they
generate.
This patch changes most of the target debug methods to be
automatically generated. All the arguments are printed, and separate
lines are printed for entering and existing the outermost call to the
target stack.
For example now you'd see:
-> multi-thread->to_terminal_ours (...)
-> multi-thread->to_is_async_p (...)
<- multi-thread->to_is_async_p (0x1ebb580) = 1
<- multi-thread->to_terminal_ours (0x1ebb580)
-> multi-thread->to_thread_address_space (...)
<- multi-thread->to_thread_address_space (0x1ebb580, 26802) = 1
In this case you can see nested calls. The "multi-thread" on the left
hand side is the topmost target's shortname.
There are some oddities with this patch. I'm on the fence about it
all, I really just wrote it on a whim.
It's not simple to convert every possible method, since a few don't
participate in target delegation.
Printing is done by type, so I introduced some new
debug-printing-specific typedefs to handle cases where it is nicer to
do something else.
On the plus side, this lays the groundwork for making targetdebug
affect every layer of the target stack. The idea would be to wrap
each target_ops in the stack with its own debug_target, and then you
could see calls propagate down the stack and back up; I suppose with
indentation to make it prettier. (That said there are some gotchas
lurking in this idea due to target stack introspection.)
Regtested on x86-64 Fedora 20.
2014-07-24 Tom Tromey <tromey@redhat.com>
* make-target-delegates (munge_type, write_debugmethod): New
functions.
(debug_names): New global.
($TARGET_DEBUG_PRINTER): New global.
(write_function_header): Strip TARGET_DEBUG_PRINTER from the type
name.
Write debug methods. Generate init_debug_target.
* target-debug.h: New file.
* target-delegates.c: Rebuild.
* target.c: Include target-debug.h.
(debug_target): Hoist definition.
(target_kill, target_get_section_table, target_memory_map)
(target_flash_erase, target_flash_done, target_detach)
(target_disconnect, target_wait, target_resume)
(target_pass_signals, target_program_signals, target_follow_fork)
(target_mourn_inferior, target_search_memory)
(target_thread_address_space, target_close)
(target_find_new_threads, target_core_of_thread)
(target_verify_memory, target_insert_mask_watchpoint)
(target_remove_mask_watchpoint): Remove targetdebug code.
(debug_to_post_attach, debug_to_prepare_to_store)
(debug_to_files_info, debug_to_insert_breakpoint)
(debug_to_remove_breakpoint, debug_to_can_use_hw_breakpoint)
(debug_to_region_ok_for_hw_watchpoint)
(debug_to_can_accel_watchpoint_condition)
(debug_to_stopped_by_watchpoint, debug_to_stopped_data_address)
(debug_to_watchpoint_addr_within_range)
(debug_to_insert_hw_breakpoint, debug_to_remove_hw_breakpoint)
(debug_to_insert_watchpoint, debug_to_remove_watchpoint)
(debug_to_terminal_init, debug_to_terminal_inferior)
(debug_to_terminal_ours_for_output, debug_to_terminal_ours)
(debug_to_terminal_save_ours, debug_to_terminal_info)
(debug_to_load, debug_to_post_startup_inferior)
(debug_to_insert_fork_catchpoint)
(debug_to_remove_fork_catchpoint)
(debug_to_insert_vfork_catchpoint)
(debug_to_remove_vfork_catchpoint)
(debug_to_insert_exec_catchpoint)
(debug_to_remove_exec_catchpoint, debug_to_has_exited)
(debug_to_can_run, debug_to_thread_architecture, debug_to_stop)
(debug_to_rcmd, debug_to_pid_to_exec_file): Remove.
(setup_target_debug): Call init_debug_target.
* target.h (TARGET_DEBUG_PRINTER): New macro.
(struct target_ops) <to_resume, to_wait, to_pass_signals,
to_program_signals>: Use TARGET_DEBUG_PRINTER.
Don Breazeal
Simon Marchi
Markus Metzger
Joel Brobecker
Tom Tromey