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2017-10-21Get rid of VEC (mem_region)Simon Marchi1-6/+6
This patch removes VEC (mem_region). Doing so requires touching a lot of little things here and there. The fields in mem_attrib are now initialized during construction. The values match those that were in default_mem_attrib (now removed). unknown_mem_attrib is also removed, and replaced with a static method (mem_attrib::unknown) that returns the equivalent. mem_region is initialized in a way similar to mem_region_init (now removed) did. I found the organization of mem_region_list and target_mem_region_list a bit confusing. Sometimes mem_region_list points to the same vector as target_mem_region_list (and therefore does not own it), and sometimes (when the user manually edits the mem regions) points to another vector, and in this case owns it. To avoid this ambiguity, I think it is simpler to have two vectors, one for target-defined regions and one for user-defined regions, and have mem_region_list point to one or the other. There are now no vector objects dynamically allocated, both are static. The make-target-delegates script does not generate valid code when a target method returns a type with a parameter list. For this reason, I created a typedef (mem_region_vector) that's only used in the target_ops structure. If you speak perl, you are welcome to improve the script! Regtested on the buildbot. gdb/ChangeLog: * memattr.h: Don't include vec.h. (struct mem_attrib): Initialize fields. <unknown>: New static method. (struct mem_region): Add constructors, operator<, initialize fields. * memattr.c: Include algorithm. (default_mem_attrib, unknown_mem_attrib): Remove. (user_mem_region_list): New global. (target_mem_region_list, mem_region_list): Change type to std::vector<mem_region>. (mem_use_target): Now a function. (target_mem_regions_valid): Change type to bool. (mem_region_lessthan, mem_region_cmp, mem_region_init): Remove. (require_user_regions): Adjust. (require_target_regions): Adjust. (create_mem_region): Adjust. (lookup_mem_region): Adjust. (invalidate_target_mem_regions): Adjust. (mem_clear): Rename to... (user_mem_clear): ... this, and adjust. (mem_command): Adjust. (info_mem_command): Adjust. (mem_enable, enable_mem_command, mem_disable, disable_mem_command): Adjust. (mem_delete): Adjust. (delete_mem_command): Adjust. * memory-map.h (parse_memory_map): Return an std::vector. * memory-map.c (parse_memory_map): Likewise. (struct memory_map_parsing_data): Add constructor. <memory_map>: Point to std::vector. (memory_map_start_memory): Adjust. (memory_map_end_memory): Adjust. (memory_map_end_property): Adjust. (clear_result): Remove. * remote.c (remote_memory_map): Return an std::vector. * target-debug.h (target_debug_print_VEC_mem_region_s__p): Remove. (target_debug_print_mem_region_vector): New. * target-delegates.c: Regenerate. * target.h (mem_region_vector): New typedef. (to_memory_map): Return mem_region_vector. (target_memory_map): Return an std::vector. * target.c (target_memory_map): Return an std::vector. (flash_erase_command): Adjust.
2017-10-14Make to_traceframe_info return a unique_ptrSimon Marchi1-5/+5
Since this target method returns an allocated object, return a unique_ptr. It allows getting rid a some cleanups here and there. I had to shuffle the includes around. First, target.h now needs to include tracepoint.h, to get the definition of traceframe_info_up. However, the definition of enum trace_find_type was later in target, so I had to move it to tracepoint.h, so that the declaration of tfind_1 could know about it. I then had to remove the include of target.h from tracepoint.h, which caused a circular dependency (it was probably included to get enum trace_find_type in the first place anyway). Regression tested on the buildbot. gdb/ChangeLog: * target.h: Include tracepoint.h. (enum trace_find_type): Move to tracepoint.h. (struct target_ops) <to_traceframe_info>: Return a unique ptr. * tracepoint.h: Don't include target.h (enum trace_find_type): Move from target.h. (parse_traceframe_info): Return a unique ptr. * tracepoint.c (current_traceframe_info): Change type to unique ptr. (free_traceframe_info): Remove. (clear_traceframe_info): Don't manually free current_traceframe_info. (free_result): Remove. (parse_traceframe_info): Return a unique ptr. (get_traceframe_info): Adjust to unique ptr. * ctf.c (ctf_traceframe_info): Return a unique ptr. * remote.c (remote_traceframe_info): Return a unique ptr. * tracefile-tfile.c (tfile_traceframe_info): Return a unique ptr. * target-debug.h (target_debug_print_traceframe_info_up): New macro. * target-delegates.c: Regenerate.
2017-09-21Add target method for converting thread handle to thread_info struct pointerKevin Buettner1-0/+37
This patch adds a target method named `to_thread_handle_to_thread_info'. It is intended to map a thread library specific thread handle (such as pthread_t for the pthread library) to the corresponding GDB internal thread_info struct (pointer). An implementation is provided for Linux pthreads; see linux-thread-db.c. gdb/ChangeLog: * target.h (struct target_ops): Add to_thread_handle_to_thread_info. (target_thread_handle_to_thread_info): Declare. * target.c (target_thread_handle_to_thread_info): New function. * target-delegates.c: Regenerate. * gdbthread.h (find_thread_by_handle): Declare. * thread.c (find_thread_by_handle): New function. * linux-thread-db.c (thread_db_thread_handle_to_thread_info): New function. (init_thread_db_ops): Register thread_db_thread_handle_to_thread_info.
2017-09-04Introduce gdb_disassembly_flagsPedro Alves1-12/+12
For some reason I ended up staring at some of the "int flags" in btrace-related code, and I got confused because I had no clue what the flags where supposed to indicate. Fix that by using enum_flags, so that: #1 - it's clear from the type what the flags are about, and #2 - the compiler can catch mismatching mistakes gdb/ChangeLog: 2017-09-04 Pedro Alves <palves@redhat.com> * cli/cli-cmds.c (print_disassembly, disassemble_current_function) (disassemble_command): Use gdb_disassembly_flags instead of bare int. * disasm.c (gdb_pretty_print_disassembler::pretty_print_insn) (dump_insns, do_mixed_source_and_assembly_deprecated) (do_mixed_source_and_assembly, do_assembly_only, gdb_disassembly): Use gdb_disassembly_flags instead of bare int. * disasm.h (DISASSEMBLY_SOURCE_DEPRECATED, DISASSEMBLY_RAW_INSN) (DISASSEMBLY_OMIT_FNAME, DISASSEMBLY_FILENAME) (DISASSEMBLY_OMIT_PC, DISASSEMBLY_SOURCE) (DISASSEMBLY_SPECULATIVE): No longer macros. Instead they're... (enum gdb_disassembly_flag): ... values of this new enumeration. (gdb_disassembly_flags): Define. (gdb_disassembly) (gdb_pretty_print_disassembler::pretty_print_insn): Use it. * mi/mi-cmd-disas.c (mi_cmd_disassemble): Use gdb_disassembly_flags instead of bare int. * record-btrace.c (btrace_insn_history) (record_btrace_insn_history, record_btrace_insn_history_range) (record_btrace_insn_history_from): Use gdb_disassembly_flags instead of bare int. * record.c (get_insn_history_modifiers, cmd_record_insn_history): Use gdb_disassembly_flags instead of bare int. * target-debug.h (target_debug_print_gdb_disassembly_flags): Define. * target-delegates.c: Regenerate. * target.c (target_insn_history, target_insn_history_from) (target_insn_history_range): Use gdb_disassembly_flags instead of bare int. * target.h: Include "disasm.h". (struct target_ops) <to_insn_history, to_insn_history_from, to_insn_history_range>: Use gdb_disassembly_flags instead of bare int. (target_insn_history, target_insn_history_from) (target_insn_history_range): Use gdb_disassembly_flags instead of bare int.
2017-04-05-Wwrite-strings: Constify target_pid_to_str and target_thread_extra_thread_infoPedro Alves1-9/+9
-Wwrite-strings flagged a missing cast for example here: static char * ravenscar_extra_thread_info (struct target_ops *self, struct thread_info *tp) { return "Ravenscar task"; Since callers are not supposed to free the string returned by these methods, change the methods' signature to return const strings. gdb/ChangeLog: 2017-04-05 Pedro Alves <palves@redhat.com> * aix-thread.c (aix_thread_pid_to_str) (aix_thread_extra_thread_info): Constify. * bsd-kvm.c (bsd_kvm_pid_to_str): Constify. * bsd-uthread.c (bsd_uthread_extra_thread_info) (bsd_uthread_pid_to_str): Constify. * corelow.c (core_pid_to_str): Constify. * darwin-nat.c (darwin_pid_to_str): Constify. * fbsd-nat.c (fbsd_pid_to_str): Constify. * fbsd-tdep.c (fbsd_core_pid_to_str, gdbarch_core_pid_to_str): Constify. * gnu-nat.c (gnu_pid_to_str): Constify. * go32-nat.c (go32_pid_to_str): Constify. * i386-cygwin-tdep.c (i386_windows_core_pid_to_str): Constify. * inf-ptrace.c (inf_ptrace_pid_to_str): Constify. * inferior.c (inferior_pid_to_str): Constify. * linux-nat.c (linux_nat_pid_to_str): Constify. * linux-tdep.c (linux_core_pid_to_str): Constify. * linux-thread-db.c (thread_db_pid_to_str) (thread_db_extra_thread_info): Constify. * nto-tdep.c (nto_extra_thread_info): Constify. * nto-tdep.h (nto_extra_thread_info): Constify. * obsd-nat.c (obsd_pid_to_str): Constify. * procfs.c (procfs_pid_to_str): Constify. * ravenscar-thread.c (ravenscar_extra_thread_info) (ravenscar_pid_to_str): Constify. * remote-sim.c (gdbsim_pid_to_str): Constify. * remote.c (remote_threads_extra_info, remote_pid_to_str): Constify. * sol-thread.c (solaris_pid_to_str): Constify. * sol2-tdep.c (sol2_core_pid_to_str): Constify. * sol2-tdep.h (sol2_core_pid_to_str): Constify. * target.c (default_pid_to_str, target_pid_to_str) (normal_pid_to_str, default_pid_to_str): Constify. * target.h (target_ops::to_pid_to_str) (target_ops::to_extra_thread_info): Constify. (target_pid_to_str, normal_pid_to_str): Constify. * windows-nat.c (windows_pid_to_str): Constify. * gdbarch.sh (core_pid_to_str): Constify. * target-delegates.c: Regenerate. * gdbarch.h, gdbarch.c: Regenerate.
2017-02-14Add method to query current recording method to target_ops.Tim Wiederhake1-0/+33
Signed-off-by: Tim Wiederhake <tim.wiederhake@intel.com> gdb/ChangeLog * record-btrace.c (record_btrace_record_method): New function. (init_record_btrace_ops): Initialize to_record_method. * record-full.c (record_full_record_method): New function. (init_record_full_ops, init_record_full_core_ops): Add record_full_record_method. * record.h (enum record_method): New enum. * target-debug.h (target_debug_print_enum_record_method: New define. * target-delegates.c: Regenerate. * target.c (target_record_method): New function. * target.h: Include record.h. (struct target_ops) <to_record_method>: New field. (target_record_method): New export. Change-Id: I05daa70e4e08a19901e848c731bb7d60cd87cc5a
2016-10-26gdb: Coalesce/aggregate (async) vCont packets/actionsPedro Alves1-0/+26
Currently, with "maint set target-non-stop on", that is, when gdb connects with the non-stop/asynchronous variant of the remote protocol, even with "set non-stop off", GDB always sends one vCont packet per thread resumed. This patch makes GDB aggregate and coalesce vCont packets, so we send vCont packets like "vCont;s:p1.1;c" in non-stop mode too. Basically, this is done by: - Adding a new target method target_commit_resume that is called after calling target_resume one or more times. When resuming a batch of threads, we'll only call target_commit_resume once after calling target_resume for all threads. - Making the remote target defer sending the actual vCont packet to target_commit_resume. Special care must be taken to avoid sending a vCont action with a "wildcard" thread-id (all threads of process / all threads) when that would resume threads/processes that should not be resumed. See remote_commit_resume comments for details. Unlike all-stop's remote_resume implementation, this handles the case of too many actions resulting in a too-big vCont packet, by flushing the vCont packet and starting a new one. E.g., imagining that the "c" action in: vCont;s:1;c overflows the packet buffer, we split the actions like: vCont;s:1 vCont;c Tested on x86_64 Fedora 20, with and without "maint set target-non-stop on". Also tested with a hack that makes remote_commit_resume flush the vCont packet after every action appended (which caught a few bugs). gdb/ChangeLog: 2016-10-26 Pedro Alves <palves@redhat.com> * inferior.h (ALL_NON_EXITED_INFERIORS): New macro. * infrun.c (do_target_resume): Call target_commit_resume. (proceed): Defer target_commit_resume while looping over threads, resuming them. Call target_commit_resume at the end. * record-btrace.c (record_btrace_commit_resume): New function. (init_record_btrace_ops): Install it as to_commit_resume method. * record-full.c (record_full_commit_resume): New function. (record_full_wait_1): Call the beneath target's to_commit_resume method. (init_record_full_ops): Install record_full_commit_resume as to_commit_resume method. * remote.c (struct private_thread_info) <last_resume_step, last_resume_sig, vcont_resumed>: New fields. (remote_add_thread): Set the new thread's vcont_resumed flag. (demand_private_info): Delete. (get_private_info_thread, get_private_info_ptid): New functions. (remote_update_thread_list): Adjust. (process_initial_stop_replies): Clear the thread's vcont_resumed flag. (remote_resume): If connected in non-stop mode, record the resume request and return early. (struct private_inferior): New. (struct vcont_builder): New. (vcont_builder_restart, vcont_builder_flush) (vcont_builder_push_action): New functions. (MAX_ACTION_SIZE): New macro. (remote_commit_resume): New function. (thread_pending_fork_status, is_pending_fork_parent_thread): New functions. (check_pending_event_prevents_wildcard_vcont_callback) (check_pending_events_prevent_wildcard_vcont): New functions. (process_stop_reply): Adjust. Clear the thread's vcont_resumed flag. (init_remote_ops): Install remote_commit_resume. * target-delegates.c: Regenerate. * target.c (defer_target_commit_resume): New global. (target_commit_resume, make_cleanup_defer_target_commit_resume): New functions. * target.h (struct target_ops) <to_commit_resume>: New field. (target_resume): Update comments. (target_commit_resume): New declaration.
2016-08-10Plumb enum remove_bp_reason all the way to target_remove_breakpointPedro Alves1-4/+6
So the target knows whether we're detaching breakpoints. Nothing uses the parameter in this patch yet. gdb/ChangeLog: 2016-08-10 Pedro Alves <palves@redhat.com> PR gdb/19187 * break-catch-sig.c (signal_catchpoint_remove_location): Adjust interface. * break-catch-syscall.c (remove_catch_syscall): * breakpoint.c (enum remove_bp_reason): Moved to breakpoint.h. (remove_breakpoint_1): Pass 'reason' down. (remove_catch_fork, remove_catch_vfork, remove_catch_solib) (remove_catch_exec, remove_watchpoint, remove_masked_watchpoint) (base_breakpoint_remove_location, bkpt_remove_location) (bkpt_probe_remove_location, bkpt_probe_remove_location): Adjust interface. * breakpoint.h (enum remove_bp_reason): Moved here from breakpoint.c. (struct breakpoint_ops) <remove_location>: Add 'reason' parameter. * corelow.c (core_remove_breakpoint): New function. (init_core_ops): Install it as to_remove_breakpoint method. * exec.c (exec_remove_breakpoint): New function. (init_exec_ops): Install it as to_remove_breakpoint method. * mem-break.c (memory_remove_breakpoint): Adjust interface. * record-btrace.c (record_btrace_remove_breakpoint): Adjust interface. * record-full.c (record_full_remove_breakpoint) (record_full_core_remove_breakpoint): Adjust interface. * remote.c (remote_remove_breakpoint): Adjust interface. * target-debug.h (target_debug_print_enum_remove_bp_reason): New macro. * target-delegates.c: Regenerate. * target.c (target_remove_breakpoint): Add 'reason' parameter. * target.h (struct target_ops) <to_remove_breakpoint>: Add 'reason' parameter. (target_remove_breakpoint, memory_remove_breakpoint): Add 'reason' parameter.
2016-07-01Optimize memory_xfer_partial for remoteDon Breazeal1-0/+31
Some analysis we did here showed that increasing the cap on the transfer size in target.c:memory_xfer_partial could give 20% or more improvement in remote load across JTAG. Transfer sizes were capped to 4K bytes because of performance problems encountered with the restore command, documented here: https://sourceware.org/ml/gdb-patches/2013-07/msg00611.html and in commit 67c059c29e1f ("Improve performance of large restore commands"). The 4K cap was introduced because in a case where the restore command requested a 100MB transfer, memory_xfer_partial would repeatedy allocate and copy an entire 100MB buffer in order to properly handle breakpoint shadow instructions, even though memory_xfer_partial would actually only write a small portion of the buffer contents. A couple of alternative solutions were suggested: * change the algorithm for handling the breakpoint shadow instructions * throttle the transfer size up or down based on the previous actual transfer size I tried implementing the throttling approach, and my implementation reduced the performance in some cases. This patch implements a new target function that returns that target's limit on memory transfer size. It defaults to ULONGEST_MAX bytes, because for native targets there is no marshaling and thus no limit is needed. For remote targets it uses get_memory_write_packet_size. gdb/ChangeLog: * remote.c (remote_get_memory_xfer_limit): New function. * target-delegates.c: Regenerate. * target.c (memory_xfer_partial): Call target_ops.to_get_memory_xfer_limit. * target.h (struct target_ops) <to_get_memory_xfer_limit>: New member.
2016-04-12Eliminate target_check_pending_interruptPedro Alves1-26/+0
This is no longer called anywhere. gdb/ChangeLog: 2016-04-12 Pedro Alves <palves@redhat.com> * target.c (target_check_pending_interrupt): Delete. * target.h (struct target_ops) <to_check_pending_interrupt>: Remove method. (target_check_pending_interrupt): Remove declaration. * target-delegates.c: Regenerate.
2016-04-12Pass Ctrl-C to the target in target_terminal_inferiorPedro Alves1-0/+21
If the user presses Ctrl-C immediately before target_terminal_inferior is called and the target is resumed, instead of after, the Ctrl-C ends up pending in the quit flag until the target next stops. remote.c has this bit to handle this: if (!target_is_async_p ()) { ofunc = signal (SIGINT, sync_remote_interrupt); /* If the user hit C-c before this packet, or between packets, pretend that it was hit right here. */ if (check_quit_flag ()) sync_remote_interrupt (SIGINT); } But that's only reachable if async is off, while async is on by default nowadays. It's also obviously not reacheable on native targets. This patch generalizes that to all targets. We can't remove that remote.c bit yet, until we get rid of the sync SIGINT handler though. That'll be done later in the series. gdb/ChangeLog: 2016-04-12 Pedro Alves <palves@redhat.com> * remote.c (remote_pass_ctrlc): New function. (init_remote_ops): Install it. * target.c (target_terminal_inferior): Pass pending Ctrl-C to the target. (target_pass_ctrlc, default_target_pass_ctrlc): New functions. * target.h (struct target_ops) <to_pass_ctrlc>: New method. (target_pass_ctrlc, default_target_pass_ctrlc): New declarations. * target-delegates.c: Regenerate.
2015-11-30Remote thread create/exit eventsPedro Alves1-0/+28
When testing with "maint set target-non-stop on", a few threading-related tests expose an issue that requires new RSP packets. Say there are 3 threads running, 1-3. If GDB tries to stop thread 1, 2 and 3, and then waits for their stops, but meanwhile say, thread 2 exits, GDB hangs forever waiting for a stop for thread 2 that won't ever happen. This patch fixes the issue by adding support for thread exit events to the protocol. However, we don't want these always enabled, as they're useless most of the time, and would slow down remote debugging. So I made it so that GDB can enable/disable them, and then made gdb do that around the cases that need it, which currently is only infrun.c:stop_all_threads. In turn, if we have thread exit events, then the extra "thread x exited" traffic slows down attach-many-short-lived-threads.exp enough that gdb has trouble keeping up with new threads that are spawned while gdb tries to stop existing ones. To fix that I added support for the counterpart thread created events too. Enabling those when we try to stop threads ensures that new threads never get a chance to themselves start new threads, killing the race. gdb/doc/ChangeLog: 2015-11-30 Pedro Alves <palves@redhat.com> * gdb.texinfo (Remote Configuration): List "set/show remote thread-events" command in configuration table. (Stop Reply Packets): Document "T05 create" stop reason and 'w' stop reply. (General Query Packets): Document QThreadEvents packet. Document QThreadEvents qSupported feature. gdb/gdbserver/ChangeLog: 2015-11-30 Pedro Alves <palves@redhat.com> * linux-low.c (handle_extended_wait): Assert that the LWP's waitstatus is TARGET_WAITKIND_IGNORE. If GDB wants to hear about thread create events, leave the new child's status pending. (linux_low_filter_event): If GDB wants to hear about thread exit events, leave the LWP marked dead and don't delete it. (linux_wait_for_event_filtered): Don't check for thread exit. (filter_exit_event): New function. (linux_wait_1): Use it, when returning an exit event. (linux_resume_one_lwp_throw): Assert that the LWP's waitstatus is TARGET_WAITKIND_IGNORE. * remote-utils.c (prepare_resume_reply): Handle TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED. * server.c (report_thread_events): New global. (handle_general_set): Handle QThreadEvents. (handle_query) <qSupported>: Handle and report QThreadEvents+; (handle_target_event): Handle TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED. * server.h (report_thread_events): Declare. gdb/ChangeLog: 2015-11-30 Pedro Alves <palves@redhat.com> * NEWS (New commands): Mention "set/show remote thread-events" commands. (New remote packets): Mention thread created/exited stop reasons and QThreadEvents packet. * infrun.c (disable_thread_events): New function. (stop_all_threads): Disable/enable thread create/exit events. Handle TARGET_WAITKIND_THREAD_EXITED. (handle_inferior_event_1): Handle TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED. * remote.c (remove_child_of_pending_fork): Also remove threads of threads that have TARGET_WAITKIND_THREAD_EXITED events. (remote_parse_stop_reply): Handle "create" magic register. Handle 'w' stop reply. (initialize_remote): Install remote_thread_events as to_thread_events target hook. (remote_thread_events): New function. * target-delegates.c: Regenerate. * target.c (target_thread_events): New function. * target.h (struct target_ops) <to_thread_events>: New field. (target_thread_events): Declare. * target/waitstatus.c (target_waitstatus_to_string): Handle TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED. * target/waitstatus.h (enum target_waitkind) <TARGET_WAITKIND_THREAD_CREATED, TARGET_WAITKIND_THREAD_EXITED): New values.
2015-11-26Constify thread name return pathSimon Marchi1-5/+5
Since this code path returns a string owned by the target (we don't know how it's allocated, could be a static read-only string), it's safer if we return a constant string. If, for some reasons, the caller wishes to modify the string, it should make itself a copy. gdb/ChangeLog: * linux-nat.c (linux_nat_thread_name): Constify return value. * target.h (struct target_ops) <to_thread_name>: Likewise. (target_thread_name): Likewise. * target.c (target_thread_name): Likewise. * target-delegates.c (debug_thread_name): Regenerate. * python/py-infthread.c (thpy_get_name): Constify local variables. * thread.c (print_thread_info): Likewise. (thread_find_command): Likewise.
2015-11-03target_ops mask_watchpoint: change int to target_hw_bp_typeSimon Marchi1-8/+8
Fixes: /home/simark/src/binutils-gdb/gdb/ppc-linux-nat.c: In function ‘int ppc_linux_insert_mask_watchpoint(target_ops*, CORE_ADDR, CORE_ADDR, int)’: /home/simark/src/binutils-gdb/gdb/ppc-linux-nat.c:1730:40: error: invalid conversion from ‘int’ to ‘target_hw_bp_type’ [-fpermissive] p.trigger_type = get_trigger_type (rw); ^ gdb/ChangeLog: * ppc-linux-nat.c (ppc_linux_insert_mask_watchpoint): Change type of rw to enum target_hw_bp_type. (ppc_linux_remove_mask_watchpoint): Likewise. * target.c (target_insert_mask_watchpoint): Likewise. (target_remove_mask_watchpoint): Likewise. * target.h (target_insert_mask_watchpoint): Likewise. (target_remove_mask_watchpoint): Likewise. (struct target_ops) <to_insert_mask_watchpoint>: Likewise. (struct target_ops) <to_remove_mask_watchpoint>: Likewise. * target-delegates.c: Regenerate.
2015-09-18target: add to_record_will_replay target methodMarkus Metzger1-0/+35
Add a new target method to_record_will_replay to query if there is a record target that will replay at least one thread matching the argument PTID if it were executed in the argument execution direction. gdb/ * record-btrace.c ((record_btrace_will_replay): New. (init_record_btrace_ops): Initialize to_record_will_replay. * record-full.c ((record_full_will_replay): New. (init_record_full_ops): Initialize to_record_will_replay. * target-delegates.c: Regenerated. * target.c (target_record_will_replay): New. * target.h (struct target_ops) <to_record_will_replay>: New. (target_record_will_replay): New. Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
2015-09-18target: add to_record_stop_replaying target methodMarkus Metzger1-0/+26
Add a new target method to_record_stop_replaying to stop replaying. gdb/ * record-btrace.c (record_btrace_resume): Call target_record_stop_replaying. (record_btrace_stop_replaying_all): New. (init_record_btrace_ops): Initialize to_record_stop_replaying. * record-full.c (record_full_stop_replaying): New. (init_record_full_ops ): Initialize to_record_stop_replaying. * target-delegates.c: Regenerated. * target.c (target_record_stop_replaying): New. * target.h (struct target_ops) <to_record_stop_replaying>: New. (target_record_stop_replaying): New.
2015-09-18target, record: add PTID argument to to_record_is_replayingMarkus Metzger1-5/+7
The to_record_is_replaying target method is used to query record targets if they are replaying. This is currently interpreted as "is any thread being replayed". Add a PTID argument and change the interpretation to "is any thread matching PTID being replayed". Change all users to pass minus_one_ptid to preserve the old meaning. The record full target does not really support multi-threading and ignores the PTID argument. gdb/ * record-btrace.c (record_btrace_is_replaying): Add ptid argument. Update users to pass minus_one_ptid. * record-full.c (record_full_is_replaying): Add ptid argument (ignored). * record.c (cmd_record_delete): Pass inferior_ptid to target_record_is_replaying. * target-delegates.c: Regenerated. * target.c (target_record_is_replaying): Add ptid argument. * target.h (struct target_ops) <to_record_is_replaying>: Add ptid argument. (target_record_is_replaying): Add ptid argument.
2015-09-15Support single step by arch or targetYao Qi1-0/+31
Nowadays, GDB only knows whether architecture supports hardware single step or software single step (through gdbarch hook software_single_step), and for a given instruction or instruction sequence, GDB knows how to do single step (hardware or software). However, GDB doesn't know whether the target supports hardware single step. It is possible that the architecture doesn't support hardware single step, such as arm, but the target supports, such as simulator. This was discussed in this thread https://www.sourceware.org/ml/gdb/2009-12/msg00033.html before. I encounter this problem for aarch64 multi-arch support. When aarch64 debugs arm program, gdbarch is arm, so software single step is still used. However, the underneath linux kernel does support hardware single step, so IWBN to use it. This patch is to add a new target_ops hook to_can_do_single_step, and only use it in arm_linux_software_single_step to decide whether or not to use hardware single step. On the native aarch64 linux target, 1 is returned. On other targets, -1 is returned. On the remote target, if the target supports s and S actions in the vCont? reply, then target can do single step. However, old GDBserver will send s and S in the reply to vCont?, which will confuse new GDB. For example, old GDBserver on arm-linux will send s and S in the reply to vCont?, but it doesn't support hardware single step. On the other hand, new GDBserver, on arm-linux for example, will not send s and S in the reply to vCont?, but old GDB thinks it doesn't support vCont packet at all. In order to address this problem, I add a new qSupported feature vContSupported, which indicates GDB wants to know the supported actions in the reply to vCont?, and qSupported response contains vContSupported if the stub is able tell supported vCont actions in the reply of vCont?. If the patched GDB talks with patched GDBserver on x86, the RSP traffic is like this: -> $qSupported:...+;vContSupported+ <- ...+;vContSupported+ ... -> $vCont? <- vCont;c;C;t;s;S;r then, GDB knows the stub can do single step, and may stop using software single step even the architecture doesn't support hardware single step. If the patched GDB talks with patched GDBserver on arm, the last vCont? reply will become: <- vCont;c;C;t GDB thinks the target doesn't support single step, so it will use software single step. If the patched GDB talks with unpatched GDBserver, the RSP traffic is like this: -> $qSupported:...+;vContSupported+ <- ...+ ... -> $vCont? <- vCont;c;C;t;s;S;r although GDBserver returns s and S, GDB still thinks GDBserver may not support single step because it doesn't support vContSupported. If the unpatched GDB talks with patched GDBserver on x86, the RSP traffic is like: -> $qSupported:...+; <- ...+;vContSupported+ ... -> $vCont? <- vCont;c;C;t;s;S;r Since GDB doesn't sent vContSupported in the qSupported feature, GDBserver sends s and S regardless of the support of hardware single step. gdb: 2015-09-15 Yao Qi <yao.qi@linaro.org> * aarch64-linux-nat.c (aarch64_linux_can_do_single_step): New function. (_initialize_aarch64_linux_nat): Install it to to_can_do_single_step. * arm-linux-tdep.c (arm_linux_software_single_step): Return 0 if target_can_do_single_step returns 1. * remote.c (struct vCont_action_support) <s, S>: New fields. (PACKET_vContSupported): New enum. (remote_protocol_features): New element for vContSupported. (remote_query_supported): Append "vContSupported+". (remote_vcont_probe): Remove support_s and support_S, use rs->supports_vCont.s and rs->supports_vCont.S instead. Disable vCont packet if c and C actions are not supported. (remote_can_do_single_step): New function. (init_remote_ops): Install it to to_can_do_single_step. (_initialize_remote): Call add_packet_config_cmd. * target.h (struct target_ops) <to_can_do_single_step>: New field. (target_can_do_single_step): New macro. * target-delegates.c: Re-generated. gdb/gdbserver: 2015-09-15 Yao Qi <yao.qi@linaro.org> * server.c (vCont_supported): New global variable. (handle_query): Set vCont_supported to 1 if "vContSupported+" matches. Append ";vContSupported+" to own_buf. (handle_v_requests): Append ";s;S" to own_buf if target supports hardware single step or vCont_supported is false. (capture_main): Set vCont_supported to zero. gdb/doc: 2015-09-15 Yao Qi <yao.qi@linaro.org> * gdb.texinfo (General Query Packets): Add vContSupported to tables of 'gdbfeatures' and 'stub features' supported in the qSupported packet, as well as to the list containing stub feature details.
2015-09-11Extended-remote follow-execDon Breazeal1-0/+30
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.
2015-09-09Merge async and sync code paths some morePedro Alves1-7/+1
This patch makes the execution control code use largely the same mechanisms in both sync- and async-capable targets. This means using continuations and use the event loop to react to target events on sync targets as well. The trick is to immediately mark infrun's event loop source after resume instead of calling wait_for_inferior. Then fetch_inferior_event is adjusted to do a blocking wait on sync targets. Tested on x86_64 Fedora 20, native and gdbserver, with and without "maint set target-async off". gdb/ChangeLog: 2015-09-09 Pedro Alves <palves@redhat.com> * breakpoint.c (bpstat_do_actions_1, until_break_command): Don't check whether the target can async. * inf-loop.c (inferior_event_handler): Only call target_async if the target can async. * infcall.c: Include top.h and interps.h. (run_inferior_call): For the interpreter to sync mode while running the infcall. Call wait_sync_command_done instead of wait_for_inferior plus normal_stop. * infcmd.c (prepare_execution_command): Don't check whether the target can async when running in the foreground. (step_1): Delete synchronous case handling. (step_once): Always install a continuation, even in sync mode. (until_next_command, finish_forward): Don't check whether the target can async. (attach_command_post_wait, notice_new_inferior): Always install a continuation, even in sync mode. * infrun.c (mark_infrun_async_event_handler): New function. (proceed): In sync mode, mark infrun's event source instead of waiting for events here. (fetch_inferior_event): If the target can't async, do a blocking wait. (prepare_to_wait): In sync mode, mark infrun's event source. (infrun_async_inferior_event_handler): No longer bail out if the target can't async. * infrun.h (mark_infrun_async_event_handler): New declaration. * linux-nat.c (linux_nat_wait_1): Remove calls to set_sigint_trap/clear_sigint_trap. (linux_nat_terminal_inferior): No longer check whether the target can async. * mi/mi-interp.c (mi_on_sync_execution_done): Update and simplify comment. (mi_execute_command_input_handler): No longer check whether the target is async. Update and simplify comment. * target.c (default_target_wait): New function. * target.h (struct target_ops) <to_wait>: Now defaults to default_target_wait. (default_target_wait): Declare. * top.c (wait_sync_command_done): New function, factored out from ... (maybe_wait_sync_command_done): ... this. * top.h (wait_sync_command_done): Declare. * target-delegates.c: Regenerate.
2015-08-25remote: allow aborting long operations (e.g., file transfers)Pedro Alves1-0/+26
Currently, when remote debugging, if you type Ctrl-C just while the target stopped for an internal event, and GDB is busy doing something that takes a while (e.g., fetching chunks of a shared library off of the target, with vFile, to process ELF headers and debug info), the Ctrl-C is lost. The patch hooks up the QUIT macro to a new target method that lets the target react to the double-Ctrl-C before the event loop is reached, which allows reacting to a double-Ctrl-C even when GDB is busy doing some long operation and not waiting for a stop reply. That end result is: (gdb) c Continuing. ^C ^C Interrupted while waiting for the program. Give up waiting? (y or n) y Quit (gdb) info threads Id Target Id Frame * 1 Thread 11673 0x00007ffff7deb240 in _dl_debug_state () from target:/lib64/ld-linux-x86-64.so.2 (gdb) If, however, GDB is waiting for a stop reply (because the target has been resumed, with e.g., vCont;c), but the target isn't responding, we now get: (gdb) c Continuing. ^C ^C The target is not responding to interrupt requests. Stop debugging it? (y or n) y Disconnected from target. (gdb) info threads No threads. This offers to disconnect, because when we're waiting for a stop reply, there's nothing else we can send the target other than an interrupt request. And if that doesn't work, there's nothing else we can do. The Ctrl-C is presently lost because until we get to a user-visible stop, the SIGINT handler that is installed is the one that forwards the interrupt to the remote side, with the \003 "packet" [1]. But, gdbserver ignores an interrupt request if the program is stopped. Still, even if it didn't, the server can only report back a stop-because-of-SIGINT when the program is next resumed. And it may take a while to actually re-resume the target. [1] - In the old sync days, the remote target would react to a double-Ctrl-C by asking users whether they wanted to give up waiting and disconnect. The code is still there, but it it isn't reacheable on most hosts, which support serial connections in async mode (probably only DJGPP doesn't). Even then, in sync mode, remote.c's SIGINT handler is only installed while the target is resumed, and is removed as soon as the target sends back a stop reply. That means that a Ctrl-C just while GDB is processing an internal event can end up with an odd "Quit" at the prompt instead of "Program stopped by SIGINT". In contrast, in async mode, remote.c's SIGINT handler is set up as long as target_terminal_inferior or target_terminal_ours_for_output are in effect (IOW, until we get a user-visible stop and call target_terminal_ours), so the user shouldn't get back a spurious Quit. However, it's still desirable to be able to interrupt a long-running GDB operation, if GDB takes a while to re-resume the target or get back to the event loop. Tested on x86_64 Fedora 20. gdb/ChangeLog: 2015-08-24 Pedro Alves <palves@redhat.com> * defs.h (maybe_quit): Declare. (QUIT): Now calls maybe_quit. * event-loop.c (clear_async_signal_handler) (async_signal_handler_is_marked): New functions. * event-loop.h (async_signal_handler_is_marked) (clear_async_signal_handler): New declarations. * remote.c (remote_check_pending_interrupt): New function. (interrupt_query): Use make_cleanup_restore_target_terminal. No longer check whether the target is async. If waiting for a stop reply, and a Ctrl-C as been sent to the target, offer to disconnect, and throw TARGET_CLOSE_ERROR instead of a quit. Otherwise do not disconnect and throw a quit. (_initialize_remote): Install remote_check_pending_interrupt as to_check_pending_interrupt. * target.c (target_check_pending_interrupt): New function. * target.h (struct target_ops) <to_check_pending_interrupt>: New field. (target_check_pending_interrupt): New declaration. * utils.c (maybe_quit): New function. * target-delegates.c: Regenerate.
2015-08-07Fix interrupt-noterm.exp on targets always in non-stopPedro Alves1-0/+28
With "maint set target-non-stop on" we get: @@ -66,13 +66,16 @@ Continuing. interrupt (gdb) PASS: gdb.base/interrupt-noterm.exp: interrupt -Program received signal SIGINT, Interrupt. -PASS: gdb.base/interrupt-noterm.exp: inferior received SIGINT -testcase src/gdb/testsuite/gdb.base/interrupt-noterm.exp completed in 0 seconds +[process 12119] #1 stopped. +0x0000003615ebc6d0 in __nanosleep_nocancel () at ../sysdeps/unix/syscall-template.S:81 +81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS) +FAIL: gdb.base/interrupt-noterm.exp: inferior received SIGINT (timeout) +testcase src/gdb/testsuite/gdb.base/interrupt-noterm.exp completed in 10 seconds That is, we get "[$thread] #1 stopped" instead of SIGINT. The issue is that we don't currently distinguish send "interrupt/ctrl-c" to target terminal vs "stop/pause" thread well; both cases go through "target_stop". And then, the native Linux backend (linux-nat.c) implements target_stop with SIGSTOP in non-stop mode, and SIGINT in all-stop mode. Since "maint set target-non-stop on" forces the backend to be always running in non-stop mode, even though the user-visible behavior is "set non-stop" is "off", "interrupt" causes a SIGSTOP instead of the SIGINT the test expects. Fix this by introducing a target_interrupt method to use in the "interrupt/ctrl-c" case, so "set non-stop off" can always work the same irrespective of "maint set target-non-stop on/off". I'm explictly considering changing the "set non-stop on" behavior as out of scope here. Most of the patch is an across-the-board rename of to_stop hook implementations to to_interrupt. The only targets where something more than a rename is being done are linux-nat.c and remote.c, which are the only targets that support async, and thus are the only ones the core side calls target_stop on. gdb/ChangeLog: 2015-08-07 Pedro Alves <palves@redhat.com> * darwin-nat.c (darwin_stop): Rename to ... (darwin_interrupt): ... this. (_initialize_darwin_inferior): Adjust. * gnu-nat.c (gnu_stop): Delete. (gnu_target): Don't install gnu_stop. * inf-ptrace.c (inf_ptrace_stop): Rename to ... (inf_ptrace_interrupt): ... this. (inf_ptrace_target): Adjust. * infcmd.c (interrupt_target_1): Use target_interrupt instead of target_stop. * linux-nat (linux_nat_stop): Rename to ... (linux_nat_interrupt): ... this. (linux_nat_stop): Reimplement. (linux_nat_add_target): Install linux_nat_interrupt. * nto-procfs.c (nto_interrupt_twice): Rename to ... (nto_handle_sigint_twice): ... this. (nto_interrupt): Rename to ... (nto_handle_sigint): ... this. Call target_interrupt instead of target_stop. (procfs_wait): Adjust. (procfs_stop): Rename to ... (procfs_interrupt): ... this. (init_procfs_targets): Adjust. * procfs.c (procfs_stop): Rename to ... (procfs_interrupt): ... this. (procfs_target): Adjust. * remote-m32r-sdi.c (m32r_stop): Rename to ... (m32r_interrupt): ... this. (init_m32r_ops): Adjust. * remote-sim.c (gdbsim_stop_inferior): Rename to ... (gdbsim_interrupt_inferior): ... this. (gdbsim_stop): Rename to ... (gdbsim_interrupt): ... this. (gdbsim_cntrl_c): Adjust. (init_gdbsim_ops): Adjust. * remote.c (sync_remote_interrupt): Adjust comments. (remote_stop_as): Rename to ... (remote_interrupt_as): ... this. (remote_stop): Adjust comment. (remote_interrupt): New function. (init_remote_ops): Install remote_interrupt. * target.c (target_interrupt): New function. * target.h (struct target_ops) <to_interrupt>: New field. (target_interrupt): New declaration. * windows-nat.c (windows_stop): Rename to ... (windows_interrupt): ... this. * target-delegates.c: Regenerate.
2015-08-07Implement all-stop on top of a target running non-stop modePedro Alves1-0/+31
This finally implements user-visible all-stop mode running with the target_ops backend always in non-stop mode. This is a stepping stone towards finer-grained control of threads, being able to do interesting things like thread groups, associating groups with breakpoints, etc. From the user's perspective, all-stop mode is really just a special case of being able to stop and resume specific sets of threads, so it makes sense to do this step first. With this, even in all-stop, the target is no longer in charge of stopping all threads before reporting an event to the core -- the core takes care of it when it sees fit. For example, when "next"- or "step"-ing, we can avoid stopping and resuming all threads at each internal single-step, and instead only stop all threads when we're about to present the stop to the user. The implementation is almost straight forward, as the heavy lifting has been done already in previous patches. Basically, we replace checks for "set non-stop on/off" (the non_stop global), with calls to a new target_is_non_stop_p function. In a few places, if "set non-stop off", we stop all threads explicitly, and in a few other places we resume all threads explicitly, making use of existing methods that were added for teaching non-stop to step over breakpoints without displaced stepping. This adds a new "maint set target-non-stop on/off/auto" knob that allows both disabling the feature if we find problems, and force-enable it for development (useful when teaching a target about this. The default is "auto", which means the feature is enabled if a new target method says it should be enabled. The patch implements the method in linux-nat.c, just for illustration, because it still returns false. We'll need a few follow up fixes before turning it on by default. This is a separate target method from indicating regular non-stop support, because e.g., while e.g., native linux-nat.c is close to regression free with all-stop-non-stop (with following patches will fixing the remaining regressions), remote.c+gdbserver will still need more fixing, even though it supports "set non-stop on". Tested on x86_64 Fedora 20, native, with and without "set displaced off", and with and without "maint set target-non-stop on"; and also against gdbserver. gdb/ChangeLog: 2015-08-07 Pedro Alves <palves@redhat.com> * NEWS: Mention "maint set/show target-non-stop". * breakpoint.c (update_global_location_list): Check target_is_non_stop_p instead of non_stop. * infcmd.c (attach_command_post_wait, attach_command): Likewise. * infrun.c (show_can_use_displaced_stepping) (can_use_displaced_stepping_p, start_step_over_inferior): Likewise. (internal_resume_ptid): New function. (resume): Use it. (proceed): Check target_is_non_stop_p instead of non_stop. If in all-stop mode but the target is always in non-stop mode, start all the other threads that are implicitly resumed too. (for_each_just_stopped_thread, fetch_inferior_event) (adjust_pc_after_break, stop_all_threads): Check target_is_non_stop_p instead of non_stop. (handle_inferior_event): Likewise. Handle detach-fork in all-stop with the target always in non-stop mode. (handle_signal_stop) <random signal>: Check target_is_non_stop_p instead of non_stop. (switch_back_to_stepped_thread): Check target_is_non_stop_p instead of non_stop. (keep_going_stepped_thread): Use internal_resume_ptid. (stop_waiting): If in all-stop mode, and the target is in non-stop mode, stop all threads. (keep_going_pass): Likewise, when starting a new in-line step-over sequence. * linux-nat.c (get_pending_status, select_event_lwp) (linux_nat_filter_event, linux_nat_wait_1, linux_nat_wait): Check target_is_non_stop_p instead of non_stop. (linux_nat_always_non_stop_p): New function. (linux_nat_stop): Check target_is_non_stop_p instead of non_stop. (linux_nat_add_target): Install linux_nat_always_non_stop_p. * target-delegates.c: Regenerate. * target.c (target_is_non_stop_p): New function. (target_non_stop_enabled, target_non_stop_enabled_1): New globals. (maint_set_target_non_stop_command) (maint_show_target_non_stop_command): New functions. (_initilize_target): Install "maint set/show target-non-stop" commands. * target.h (struct target_ops) <to_always_non_stop_p>: New field. (target_non_stop_enabled): New declaration. (target_is_non_stop_p): New declaration. gdb/doc/ChangeLog: 2015-08-07 Pedro Alves <palves@redhat.com> * gdb.texinfo (Maintenance Commands): Document "maint set/show target-non-stop".
2015-07-31Mostly trivial enum fixesSimon Marchi1-12/+12
This is a patch I extracted from Pedro's C++ branch. It contains the most trivial enum fixes, where an integer type/value was used instead of the appropriate enum type/value. It fixes many C++ errors, since in C++ you can't mix integers and enums implicitely. Regardless of the C++ conversion, I think this is a good cleanup to make use of the appropriate enum types. Regression-tested on native x86_64. gdb/ChangeLog: * aarch64-linux-nat.c (aarch64_linux_can_use_hw_breakpoint): Use enum type or value instead of integer. (aarch64_linux_insert_watchpoint): Likewise. (aarch64_linux_remove_watchpoint): Likewise. * ada-lang.c (ada_op_print_tab): Likewise. * amd64-linux-tdep.c (amd64_canonicalize_syscall): Likewise. (amd64_linux_syscall_record_common): Likewise. * arch-utils.c (target_byte_order_user): Likewise. (default_byte_order): Likewise. * arm-linux-nat.c (arm_linux_can_use_hw_breakpoint): Likewise. (arm_linux_get_hwbp_type): Likewise. (arm_linux_hw_watchpoint_initialize): Likewise. (arm_linux_insert_watchpoint): Likewise. * arm-linux-tdep.c (arm_canonicalize_syscall): Likewise. (arm_linux_syscall_record): Likewise. * breakpoint.c (update_watchpoint): Likewise. (breakpoint_here_p): Likewise. (bpstat_print): Likewise. (enable_breakpoint_disp): Likewise. * c-lang.c (c_op_print_tab): Likewise. * cli/cli-decode.c (add_info_alias): Likewise. * d-lang.c (d_op_print_tab): Likewise. * eval.c (evaluate_subexp_standard): Likewise. * f-exp.y (dot_ops): Likewise. (f77_keywords): Likewise. * f-lang.c (f_op_print_tab): Likewise. * go-lang.c (go_op_print_tab): Likewise. * guile/scm-breakpoint.c (gdbscm_make_breakpoint): Likewise. * guile/scm-cmd.c (gdbscm_make_command): Likewise. * guile/scm-param.c (gdbscm_make_parameter): Likewise. * guile/scm-pretty-print.c (gdbscm_apply_val_pretty_printer): Likewise. * guile/scm-string.c (struct scm_to_stringn_data): Likewise. (struct scm_from_stringn_data): Likewise. * i386-linux-tdep.c (i386_canonicalize_syscall): Likewise. * ia64-linux-nat.c (ia64_linux_insert_watchpoint): Likewise. (ia64_linux_remove_watchpoint): Likewise. (ia64_linux_can_use_hw_breakpoint): Likewise. * infrun.c (print_stop_event): Likewise. * jv-lang.c (java_op_print_tab): Likewise. * linux-nat.c (linux_proc_xfer_partial): Likewise. * linux-nat.h (struct lwp_info): Likewise. * linux-thread-db.c (enable_thread_event): Likewise. * m2-lang.c (m2_op_print_tab): Likewise. * mi/mi-cmd-stack.c (mi_cmd_stack_list_locals): Likewise. (mi_cmd_stack_list_variables): Likewise. * mi/mi-main.c (mi_cmd_trace_frame_collected): Likewise. * mi/mi-out.c (mi_table_begin): Likewise. (mi_table_header): Likewise. * mips-linux-nat.c (mips_linux_can_use_hw_breakpoint): Likewise. (mips_linux_insert_watchpoint): Likewise. (mips_linux_remove_watchpoint): Likewise. * nat/mips-linux-watch.c (mips_linux_watch_type_to_irw): Likewise. * nat/mips-linux-watch.h (struct mips_watchpoint): Likewise. (mips_linux_watch_type_to_irw): Likewise. * nto-procfs.c (procfs_can_use_hw_breakpoint): Likewise. (procfs_insert_hw_watchpoint): Likewise. (procfs_remove_hw_watchpoint): Likewise. (procfs_hw_watchpoint): Likewise. (procfs_can_use_hw_breakpoint): Likewise. (procfs_remove_hw_watchpoint): Likewise. (procfs_insert_hw_watchpoint): Likewise. * p-lang.c (pascal_op_print_tab): Likewise. * ppc-linux-nat.c (ppc_linux_can_use_hw_breakpoint): Likewise. * ppc-linux-tdep.c (ppu2spu_unwind_register): Likewise. * ppc-sysv-tdep.c (get_decimal_float_return_value): Likewise. * procfs.c (procfs_can_use_hw_breakpoint): Likewise. (procfs_insert_watchpoint): Likewise. (procfs_remove_watchpoint): Likewise. * psymtab.c (recursively_search_psymtabs): Likewise. * remote-m32r-sdi.c (m32r_can_use_hw_watchpoint): Likewise. (m32r_insert_watchpoint): Likewise. * remote-mips.c (mips_can_use_watchpoint): Likewise. (mips_insert_watchpoint): Likewise. (mips_remove_watchpoint): Likewise. * remote.c (watchpoint_to_Z_packet): Likewise. (remote_insert_watchpoint): Likewise. (remote_remove_watchpoint): Likewise. (remote_check_watch_resources): Likewise. * s390-linux-nat.c (s390_insert_watchpoint): Likewise. (s390_remove_watchpoint): Likewise. (s390_can_use_hw_breakpoint): Likewise. * s390-linux-tdep.c (s390_gdbarch_init): Likewise. * spu-linux-nat.c (spu_can_use_hw_breakpoint): Likewise. * target.h (struct target_ops): Likewise. * tilegx-tdep.c (tilegx_analyze_prologue): Likewise. * ui-out.c (struct ui_out_hdr): Likewise. (append_header_to_list): Likewise. (get_next_header): Likewise. (verify_field): Likewise. (ui_out_begin): Likewise. (ui_out_field_int): Likewise. (ui_out_field_fmt_int): Likewise. (ui_out_field_skip): Likewise. (ui_out_field_string): Likewise. (ui_out_field_fmt): Likewise. * varobj.c (new_variable): Likewise. * x86-nat.c (x86_insert_watchpoint): Likewise. (x86_remove_watchpoint): Likewise. (x86_can_use_hw_breakpoint): Likewise. * xtensa-tdep.h (struct gdbarch_tdep): Likewise. * inflow.c (enum gdb_has_a_terminal_flag_enum): Add name to previously anonymous enumeration type.. * linux-record.h (enum gdb_syscall): Add gdb_sys_no_syscall value. * target-debug.h (target_debug_print_enum_target_hw_bp_type): New. (target_debug_print_enum_bptype): New. * target-delegates.c: Regenerate.
2015-04-02Introduce target_filesystem_is_localGary Benson1-0/+31
This commit introduces a new target method target_filesystem_is_local which can be used to determine whether or not the filesystem accessed by the target_fileio_* methods is the local filesystem. gdb/ChangeLog: * target.h (struct target_ops) <to_filesystem_is_local>: New field. (target_filesystem_is_local): New macro. * target-delegates.c: Regenerate. * remote.c (remote_filesystem_is_local): New function. (init_remote_ops): Initialize to_filesystem_is_local.
2015-03-25Simplify target_async hook interfacePedro Alves1-8/+6
All callers of target_async pass it the same callback (inferior_event_handler). Since both common code and target backends need to be able to put the target in and out of target async mode at any given time, there's really no way that a different callback could be passed. This commit simplifies things, and removes the indirection altogether. Bonus: with this, gdb's target_async method ends up with the same signature as gdbserver's. Tested on x86_64 Fedora 20, native and gdbserver. gdb/ChangeLog: 2015-03-25 Pedro Alves <palves@redhat.com> * target.h <to_async>: Replace 'callback' and 'context' parameters with boolean 'enable' parameter. (target_async): Replace CALLBACK and CONTEXT parameters with boolean ENABLE parameter. * inf-loop.c (inferior_event_handler): Adjust. * linux-nat.c (linux_nat_attach, linux_nat_resume) (linux_nat_resume): Adjust. (async_client_callback, async_client_context): Delete. (handle_target_event): Call inferior_event_handler directly. (linux_nat_async): Replace 'callback' and 'context' parameters with boolean 'enable' parameter. Adjust. Remove references to async_client_callback and async_client_context. (linux_nat_close): Adjust. * record-btrace.c (record_btrace_async): Replace 'callback' and 'context' parameters with boolean 'enable' parameter. Adjust. (record_btrace_resume): Adjust. * record-full.c (record_full_async): Replace 'callback' and 'context' parameters with boolean 'enable' parameter. Adjust. (record_full_resume, record_full_core_resume): Adjust. * remote.c (struct remote_state) <async_client_callback, async_client_context>: Delete fields. (remote_start_remote, extended_remote_attach_1, remote_resume) (extended_remote_create_inferior): Adjust. (remote_async_serial_handler): Call inferior_event_handler directly. (remote_async): Replace 'callback' and 'context' parameters with boolean 'enable' parameter. Adjust. * top.c (gdb_readline_wrapper_cleanup, gdb_readline_wrapper): Adjust. * target-delegates.c: Regenerate.
2015-03-04garbage collect target_decr_pc_after_breakPedro Alves1-27/+0
record-btrace was the only target making use of this, and it no longer uses it. gdb/ChangeLog: 2015-03-04 Pedro Alves <palves@redhat.com> * target.h (struct target_ops) <to_decr_pc_after_break>: Delete. (target_decr_pc_after_break): Delete declaration. * target.c (default_target_decr_pc_after_break) (target_decr_pc_after_break): Delete. * linux-nat.c (check_stopped_by_breakpoint, linux_nat_wait_1): Use gdbarch_decr_pc_after_break instead of target_decr_pc_after_break. * linux-thread-db.c (check_event): Likewise. * infrun.c (adjust_pc_after_break): Likewise. * darwin-nat.c (cancel_breakpoint): Likewise. * aix-thread.c (aix_thread_wait): Likewise. * target-delegates.c: Regenerate.
2015-03-04Teach GDB about targets that can tell whether a trap is a breakpoint eventPedro Alves1-0/+124
The moribund locations heuristics are problematic. This patch teaches GDB about targets that can reliably tell whether a trap was caused by a software or hardware breakpoint, and thus don't need moribund locations, thus bypassing all the problems that mechanism has. The non-stop-fair-events.exp test is frequently failing currently. E.g., see https://sourceware.org/ml/gdb-testers/2015-q1/msg03148.html. The root cause is a fundamental problem with moribund locations. For example, the stepped_breakpoint logic added by af48d08f breaks in this case (which is what happens with that test): - Step thread A, no breakpoint is set at PC. - The kernel doesn't schedule thread A yet. - Insert breakpoint at A's PC, for some reason (e.g., a step-resume breakpoint for thread B). - Kernel finally schedules thread A. - thread A's stepped_breakpoint flag is not set, even though it now stepped a breakpoint instruction. - adjust_pc_after_break gets the PC wrong, because PC == PREV_PC, but stepped_breakpoint is not set. We needed the stepped_breakpoint logic to workaround moribund locations, because otherwise adjust_pc_after_break could apply an adjustment when it shouldn't just because there _used_ to be a breakpoint at PC (a moribund breakpoint location). For example, on x86, that's wrong if the thread really hasn't executed an int3, but instead executed some other 1-byte long instruction. Getting the PC adjustment wrong of course leads to the inferior executing the wrong instruction. Other problems with moribund locations are: - if a true SIGTRAP happens to be raised when the program is executing the PC that used to have a breakpoint, GDB will assume that is a trap for a breakpoint that has recently been removed, and thus we miss reporting the random signal to the user. - to minimize that, we get rid of moribund location after a while. That while is defined as just a certain number of events being processed. That number of events sometimes passes by before a delayed breakpoint is processed, and GDB confuses the trap for a random signal, thus reporting the random trap. Once the user resumes the thread, the program crashes because the PC was not adjusted... The fix for all this is to bite the bullet and get rid of heuristics and instead rely on the target knowing accurately what caused the SIGTRAP. The target/kernel/stub is in the best position to know what that, because it can e.g. consult priviledged CPU flags GDB has no access to, or by knowing which exception vector entry was called when the instruction trapped, etc. Most debug APIs I've seen to date report breakpoint hits as a distinct event in some fashion. For example, on the Linux kernel, whether a breakpoint was executed is exposed to userspace in the si_code field of the SIGTRAP's siginfo. On Windows, the debug API reports a EXCEPTION_BREAKPOINT exception code. We needed to keep around deleted breakpoints in an on-the-side list (the moribund locations) for two main reasons: - Know that a SIGTRAP actually is a delayed event for a hit of a breakpoint that was removed before the event was processed, and thus should not be reported as a random signal. - So we still do the decr_pc_after_break adjustment in that case, so that the thread is resumed at the correct address. In the new model, if GDB processes an event the target tells is a breakpoint trap, and GDB doesn't find the corresponding breakpoint in its breakpoint tables, it means that event is a delayed event for a breakpoint that has since been removed, and thus the event should be ignored. For the decr_pc_after_after issue, it ends up being much simpler that on targets that can reliably tell whether a breakpoint trapped, for the breakpoint trap to present the PC already adjusted. Proper multi-threading support already implies that targets needs to be doing decr_pc_after_break adjustment themselves, otherwise for example, in all-stop if two threads hit a breakpoint simultaneously, and the user does "info threads", he'll see the non-event thread that hit the breakpoint stopped at the wrong PC. This way (target adjusts) also ends up eliminating the need for some awkward re-incrementing of the PC in the record-full and Linux targets that we do today, and the need for the target_decr_pc_after_break hook. If the target always adjusts, then there's a case where GDB needs to re-increment the PC. Say, on x86, an "int3" instruction that was explicitly written in the program traps. In this case, GDB should report a random SIGTRAP signal to the user, with the PC pointing at the instruction past the int3, just like if GDB was not debugging the program. The user may well decide to pass the SIGTRAP to the program because the program being debugged has a SIGTRAP handler that handles its own breakpoints, and expects the PC to be unadjusted. Tested on x86-64 Fedora 20. gdb/ChangeLog: 2015-03-04 Pedro Alves <palves@redhat.com> * breakpoint.c (need_moribund_for_location_type): New function. (bpstat_stop_status): Don't skipping checking moribund locations of breakpoint types which the target tell caused a stop. (program_breakpoint_here_p): New function, factored out from ... (bp_loc_is_permanent): ... this. (update_global_location_list): Don't create a moribund location if the target supports reporting stops of the type of the removed breakpoint. * breakpoint.h (program_breakpoint_here_p): New declaration. * infrun.c (adjust_pc_after_break): Return early if the target has already adjusted the PC. Add comments. (handle_signal_stop): If nothing explains a signal, and the target tells us the stop was caused by a software breakpoint, check if there's a breakpoint instruction in the memory. If so, adjust the PC before presenting the stop to the user. Otherwise, ignore the trap. If nothing explains a signal, and the target tells us the stop was caused by a hardware breakpoint, ignore the trap. * target.h (struct target_ops) <to_stopped_by_sw_breakpoint, to_supports_stopped_by_sw_breakpoint, to_stopped_by_hw_breakpoint, to_supports_stopped_by_hw_breakpoint>: New fields. (target_stopped_by_sw_breakpoint) (target_supports_stopped_by_sw_breakpoint) (target_stopped_by_hw_breakpoint) (target_supports_stopped_by_hw_breakpoint): Define. * target-delegates.c: Regenerate.
2015-02-09record btrace: add configuration structMarkus Metzger1-5/+40
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 &current_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.
2015-02-09btrace: add format argument to supports_btraceMarkus Metzger1-5/+7
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.
2015-02-09btrace: add struct btrace_dataMarkus Metzger1-4/+4
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.
2014-10-15Push pruning old threads down to the targetPedro Alves1-11/+11
When GDB wants to sync the thread list with the target's (e.g., due to "info threads"), it calls update_thread_list: update_thread_list (void) { prune_threads (); target_find_new_threads (); update_threads_executing (); } And then prune_threads does: prune_threads (void) { struct thread_info *tp, *next; for (tp = thread_list; tp; tp = next) { next = tp->next; if (!thread_alive (tp)) delete_thread (tp->ptid); } } Calling thread_live on each thread one by one is expensive. E.g., on Linux, it ends up doing kill(SIG0) once for each thread. Not a big deal, but still a bunch of syscalls... With the remote target, it's cumbersome. That thread_alive call ends up generating one T packet per thread: Sending packet: $Tp2141.2150#82...Packet received: OK Sending packet: $Tp2141.214f#b7...Packet received: OK Sending packet: $Tp2141.2141#82...Packet received: OK Sending packet: $qXfer:threads:read::0,fff#03...Packet received: l<threads>\n<thread id="p2141.2141" core="2"/>\n<thread id="p2141.214f" core="1"/>\n<thread id="p2141.2150" core="2"/>\n</threads>\n That seems a bit silly when target_find_new_threads method implementations will always fetch the whole current set of target threads, and then add those that are not in GDB's thread list, to GDB's thread list. This patch thus pushes down the responsibility of pruning dead threads to the target_find_new_threads method instead, so a target may implement pruning dead threads however it wants. Once we do that, target_find_new_threads becomes a misnomer, so the patch renames it to target_update_thread_list. The patch doesn't attempt to do any optimization to any target yet. It simply exports prune_threads, and makes all implementations of target_update_thread_list call that. It's meant to be a no-op. gdb/ 2014-10-15 Pedro Alves <palves@redhat.com> * ada-tasks.c (print_ada_task_info, task_command_1): Adjust. * bsd-uthread.c (bsd_uthread_find_new_threads): Rename to ... (bsd_uthread_update_thread_list): ... this. Call prune_threads. (bsd_uthread_target): Adjust. * corelow.c (core_open): Adjust. * dec-thread.c (dec_thread_find_new_threads): Update comment. (dec_thread_update_thread_list): New function. (init_dec_thread_ops): Adjust. * gdbthread.h (prune_threads): New declaration. * linux-thread-db.c (thread_db_find_new_threads): Rename to ... (thread_db_update_thread_list): ... this. Call prune_threads. (init_thread_db_ops): Adjust. * nto-procfs.c (procfs_find_new_threads): Rename to ... (procfs_update_thread_list): ... this. Call prune_threads. (procfs_attach, procfs_create_inferior, init_procfs_targets): Adjust. * obsd-nat.c (obsd_find_new_threads): Rename to ... (obsd_update_thread_list): ... this. Call prune_threads. (obsd_add_target): Adjust. * procfs.c (procfs_target): Adjust. (procfs_notice_thread): Update comment. (procfs_find_new_threads): Rename to ... (procfs_update_thread_list): ... this. Call prune_threads. * ravenscar-thread.c (ravenscar_update_inferior_ptid): Update comment. (ravenscar_wait): Adjust. (ravenscar_find_new_threads): Rename to ... (ravenscar_update_thread_list): ... this. Call prune_threads. (init_ravenscar_thread_ops): Adjust. * record-btrace.c (record_btrace_find_new_threads): Rename to ... (record_btrace_update_thread_list): ... this. Adjust comment. (init_record_btrace_ops): Adjust. * remote.c (remote_threads_info): Rename to ... (remote_update_thread_list): ... this. Call prune_threads. (remote_start_remote, extended_remote_attach_1, init_remote_ops): Adjust. * sol-thread.c (check_for_thread_db): Adjust. (sol_find_new_threads_callback): Rename to ... (sol_update_thread_list_callback): ... this. (sol_find_new_threads): Rename to ... (sol_update_thread_list): ... this. Call prune_threads. Adjust. (sol_get_ada_task_ptid, init_sol_thread_ops): Adjust. * target-delegates.c: Regenerate. * target.c (target_find_new_threads): Rename to ... (target_update_thread_list): ... this. * target.h (struct target_ops): Rename to_find_new_threads field to to_update_thread_list. (target_find_new_threads): Rename to ... (target_update_thread_list): ... this. * thread.c (prune_threads): Make extern. (update_thread_list): Adjust.
2014-08-27Fix terminal state corruption when starting a program from within TUIPatrick Palka1-26/+0
The TUI terminal state becomes corrupted (e.g. key sequences such as Alt_F and Alt_B no longer work) when one attaches to an inferior process (via "run" or "attach") from within TUI. This terminal corruption remains until you switch out of TUI mode. This happens because the terminal state is not properly saved when switching to and out from TUI mode. Although the functions tui_enable() and tui_disable() both call the function target_terminal_save_ours() to save the terminal state, this function is a no-op unless GDB has already attached to an inferior process. This is because only the "native" target has a useful implementation of target_terminal_save_ours() (namely child_terminal_save_ours()) and we only have the "native" target in our target vector if GDB has already attached to an inferior process. So without an inferior process, switching to and from TUI mode does not actually save the terminal state. Therefore when you attach to an inferior process from within TUI mode, the proper terminal state is not restored (after swapping from the inferior's terminal back to the GDB terminal). To fix this we just have to ensure that the terminal state is always being properly saved when switching from and to TUI mode. To achieve this, this patch removes the polymorphic function target_terminal_save_ours() and replaces it with a regular function gdb_save_tty_state() that always saves the terminal state. Tested on x86_64-unknown-linux-gnu by running "make check", no new regressions. gdb/ChangeLog: * target.h (struct target_ops::to_terminal_save_ours): Remove declaration. (target_terminal_save_ours): Remove macro. * target-delegates.c: Regenerate. * inf-child.c (inf_child_target): Don't set the nonexistent field to_terminal_save_ours. * inferior.h (child_terminal_save_ours): Remove declaration. * terminal.h (gdb_save_tty_state): New declaration. * inflow.c (child_terminal_save_ours): Rename to ... (gdb_save_tty_state): ... this. * tui/tui.c: Include terminal.h. (tui_enable): Use gdb_save_tty_state instead of target_terminal_save_ours. (tui_disable): Likewise.
2014-07-24auto-generate most target debug methodsTom Tromey1-4/+2228
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.
2014-07-23rewrite make-target-delegates matching codeTom Tromey1-14/+14
This patch rewrites the make-target-delegates matching code a little bit. The result is functionally the same (the output has some small whitespace differences), but the new code is more forgiving regarding the formatting of target.h. In particular now there's no need to ensure that the return type and the method name appear on the same line. 2014-07-23 Tom Tromey <tromey@redhat.com> * make-target-delegates ($ARGS_PART): Match trailing close paren. ($INTRO_PART): Don't match whitespace. ($METHOD_TRAILER): Move earlier. Remove trailing semicolon and argument matching. ($METHOD): Add $METHOD_TRAILER. (trim): Rewrite. (scan_target_h): New sub. Change main loop not to collect state. * target-delegates.c: Rebuild.
2014-07-16rebuild target-delegates.cTom Tromey1-0/+15
target-delegates.c was out of date. This patch rebuilds it. Built and regtested on x86-64 Fedora 20. Committed as obvious. 2014-07-16 Tom Tromey <tromey@redhat.com> * target-delegates.c: Rebuild.
2014-07-07convert to_get_thread_local_address to use target delegationTom Tromey1-0/+16
This converts to_get_thread_local_address to use TARGET_DEFAULT_NORETURN. One possible oddity is that this changes the text of the kind of exception thrown in some cases. This doesn't seem to be a problem; in fact perhaps the final call to 'error' in target_translate_tls_address should be changed to call generic_tls_error. 2014-07-07 Tom Tromey <tromey@redhat.com> * target.h (struct target_ops) <to_get_thread_local_address>: Use TARGET_DEFAULT_NORETURN. * target.c (generic_tls_error): New function. (target_translate_tls_address): Don't search target stack. * target-delegates.c: Rebuild. * ppc-linux-tdep.c (ppc_linux_spe_context): Don't search target stack. * linux-thread-db.c (thread_db_get_thread_local_address): Unconditionally call beneath target.
2014-06-26constify get_bookmark and goto_bookmarkTom Tromey1-4/+4
This makes arguments to to_get_bookmark and to_goto_bookmark const and fixes the fallout. Tested by rebuilding. The only thing of note is the new split between cmd_record_goto and record_goto -- basically separating the CLI function from a new internal API, to allow const propagation. 2014-06-26 Tom Tromey <tromey@redhat.com> * record-full.c (record_full_get_bookmark): Make "args" const. (record_full_goto_bookmark): Make "raw_bookmark" const. * record.c (record_goto): New function. (cmd_record_goto): Use it. Now static. * record.h (record_goto): Declare. (cmd_record_goto): Remove declaration. * target-delegates.c: Rebuild. * target.h (struct target_ops) <to_get_bookmark, to_goto_bookmark>: Make parameter const.
2014-06-26constify to_loadTom Tromey1-2/+2
This makes the argument to the target_ops to_load method "const", and fixes up the fallout. Tested by rebuilding all the affected files. 2014-06-26 Tom Tromey <tromey@redhat.com> * defs.h (generic_load): Update. * m32r-rom.c (m32r_load_gen): Make "filename" const. * monitor.c (monitor_load): Make "args" const. * remote-m32r-sdi.c (m32r_load): Make "args" const. * remote-mips.c (mips_load_srec, pmon_load_fast): Make "args" const. (mips_load): Make "file" const. * remote-sim.c (gdbsim_load): Make "args" const. * remote.c (remote_load): Make "name" const. * symfile.c (generic_load): Make "args" const. * target-delegates.c: Rebuild. * target.c (target_load): Make "arg" const. (debug_to_load): Make "args" const. * target.h (struct target_ops) <to_load>: Make parameter const. (target_load): Update.
2014-06-25gcore, target: allow target to prepare/cleanup for/after core file generationMarkus Metzger1-0/+30
Add new target functions to_prepare_to_generate_core and to_done_generating_core that are called before and after generating a core file, respectively. This allows targets to prepare for core file generation and to clean up afterwards. gdb/ * target.h (target_ops) <to_prepare_to_generate_core> <to_done_generating_core>: New. (target_prepare_to_generate_core, target_done_generating_core): New. * target.c (target_prepare_to_generate_core) (target_done_generating_core): New. * target-delegates.c: Regenerate. * gcore.c: (write_gcore_file): Rename to ... (write_gcore_file_1): ...this. (write_gcore_file): Call target_prepare_to_generate_core and target_done_generating_core.
2014-06-16constify to_disconnectTom Tromey1-2/+2
This constifies an parameter of to_disconnect and updates target_disconnect as well. 2014-06-16 Tom Tromey <tromey@redhat.com> * target.h (struct target_ops) <to_disconnect>: Make parameter const. (target_disconnect): Update. * target.c (target_disconnect): Make "args" const. * target-delegates.c: Rebuild. * remote.c (remote_disconnect): Update. * record.h (record_disconnect): Update. * record.c (record_disconnect): Update. * inf-child.c (inf_child_disconnect): Update.
2014-06-16constify to_rcmdTom Tromey1-1/+1
This makes the "command" parameter of the to_rcmd target method const. 2014-06-16 Tom Tromey <tromey@redhat.com> * target.h (struct target_ops) <to_rcmd>: Make "command" const. * target.c (debug_to_rcmd, default_rcmd): Update. * target-delegates.c: Rebuild. * remote.c (remote_rcmd): Update. * monitor.c (monitor_rcmd): Update.
2014-06-04convert to_thread_address_space to use TARGET_DEFAULT_FUNCTom Tromey1-0/+10
This converts to_thread_address_space to use TARGET_DEFAULT_FUNC. This method was one of a handful not using the normal target delegation approach. The only rationale here is consistency in the target vector. Built and regtested on x86-64 Fedora 20. 2014-06-04 Tom Tromey <tromey@redhat.com> * target-delegates.c: Rebuild. * target.c (default_thread_address_space): New function. (target_thread_address_space): Simplify. * target.h (struct target_ops) <to_thread_address_space>: Add TARGET_DEFAULT_FUNC.
2014-05-20Make compare-sections work against all targets; add compare-sections [-r] tests.Pedro Alves1-7/+1
This does two things: 1. Adds a test. Recently compare-sections got a new "-r" switch, but given no test existed for compare-sections, the patch was allowed in with no testsuite addition. This now adds a test for both compare-sections and compare-sections -r. 2. Makes the compare-sections command work against all targets. Currently, compare-sections only works with remote targets, and only those that support the qCRC packet. The patch makes it so that if the target doesn't support accelerating memory verification, then GDB falls back to comparing memory itself. This is of course slower, but it's better than nothing, IMO. While testing against extended-remote GDBserver I noticed that we send the qCRC request to the target if we're connected, but not yet running a program. That can't work of course -- the patch fixes that. This all also goes in the direction of bridging the local/remote parity gap. I didn't decouple 1. from 2., because that would mean that the test would need to handle the case of the target not supporting the command. Tested on x86_64 Fedora 17, native, remote GDBserver, and extended-remote GDBserver. I also hack-disabled qCRC support to make sure the fallback paths in remote.c work. gdb/doc/ 2014-05-20 Pedro Alves <palves@redhat.com> * gdb.texinfo (Memory) <compare-sections>: Generalize comments to not be remote specific. Add cross reference to the qCRC packet. (Separate Debug Files): Update cross reference to the qCRC packet. (General Query Packets) <qCRC packet>: Add anchor. gdb/ 2014-05-20 Pedro Alves <palves@redhat.com> * NEWS: Mention that compare-sections now works with all targets. * remote.c (PACKET_qCRC): New enum value. (remote_verify_memory): Don't send qCRC if the target has no execution. Use packet_support/packet_ok. If the target doesn't support the qCRC packet, fallback to a deep memory copy. (compare_sections_command): Say "target image" instead of "remote executable". (_initialize_remote): Add PACKET_qCRC to the list of config packets that have no associated command. Extend comment. * target.c (simple_verify_memory, default_verify_memory): New function. * target.h (struct target_ops) <to_verify_memory>: Default to default_verify_memory. (simple_verify_memory): New declaration. * target-delegates.c: Regenerate. gdb/testsuite/ 2014-05-20 Pedro Alves <palves@redhat.com> * gdb.base/compare-sections.c: New file. * gdb.base/compare-sections.exp: New file.
2014-03-12fix regressions with target-asyncTom Tromey1-12/+30
A patch in the target cleanup series caused a regression when using record with target-async. Version 4 of the patch is here: https://sourceware.org/ml/gdb-patches/2014-03/msg00159.html The immediate problem is that record supplies to_can_async_p and to_is_async_p methods, but does not supply a to_async method. So, when target-async is set, record claims to support async -- but if the underlying target does not support async, then the to_async method call will end up in that method's default implementation, namely tcomplain. This worked previously because the record target used to provide a to_async method; one that (erroneously, only at push time) checked the other members of the target stack, and then simply dropped to_async calls in the "does not implement async" case. My first thought was to simply drop tcomplain as the default for to_async. This works, but Pedro pointed out that the only reason record has to supply to_can_async_p and to_is_async_p is that these default to using the find_default_run_target machinery -- and these defaults are only needed by "run" and "attach". So, a nicer solution presents itself: change run and attach to explicitly call into the default run target when needed; and change to_is_async_p and to_can_async_p to default to "return 0". This makes the target stack simpler to use and lets us remove the method implementations from record. This is also in harmony with other plans for the target stack; namely trying to reduce the impact of find_default_run_target. This approach makes it clear that find_default_is_async_p is not needed -- it is asking whether a target that may not even be pushed is actually async, which seems like a nonsensical question. While an improvement, this approach proved to introduce the same bug when using the core target. Looking a bit deeper, the issue is that code in "attach" and "run" may need to use either the current target stack or the default run target -- but different calls into the target API in those functions could wind up querying different targets. This new patch makes the target to use more explicit in "run" and "attach". Then these commands explicitly make the needed calls against that target. This ensures that a single target is used for all relevant operations. This lets us remove a couple find_default_* functions from various targets, including the dummy target. I think this is a decent understandability improvement. One issue I see with this patch is that the new calls in "run" and "attach" are not very much like the rest of the target API. I think fundamentally this is due to bad factoring in the target API, which may need to be fixed for multi-target. Tackling that seemed ambitious for a regression fix. While working on this I noticed that there don't seem to be any test cases that involve both target-async and record, so this patch changes break-precsave.exp to add some. It also changes corefile.exp to add some target-async tests; these pass with current trunk and with this patch applied, but fail with the v1 patch. This patch differs from v4 in that it moves initialization of to_can_async_p and to_supports_non_stop into inf-child, adds some assertions to complete_target_initialization, and adds some comments to target.h. Built and regtested on x86-64 Fedora 20. 2014-03-12 Tom Tromey <tromey@redhat.com> * inf-child.c (return_zero): New function. (inf_child_target): Set to_can_async_p, to_supports_non_stop. * aix-thread.c (aix_thread_inferior_created): New function. (aix_thread_attach): Remove. (init_aix_thread_ops): Don't set to_attach. (_initialize_aix_thread): Register inferior_created observer. * corelow.c (init_core_ops): Don't set to_attach or to_create_inferior. * exec.c (init_exec_ops): Don't set to_attach or to_create_inferior. * infcmd.c (run_command_1): Use find_run_target. Make direct target calls. (attach_command): Use find_attach_target. Make direct target calls. * record-btrace.c (init_record_btrace_ops): Don't set to_create_inferior. * record-full.c (record_full_can_async_p, record_full_is_async_p): Remove. (init_record_full_ops, init_record_full_core_ops): Update. Don't set to_create_inferior. * target.c (complete_target_initialization): Add assertion. (target_create_inferior): Remove. (find_default_attach, find_default_create_inferior): Remove. (find_attach_target, find_run_target): New functions. (find_default_is_async_p, find_default_can_async_p) (target_supports_non_stop, target_attach): Remove. (init_dummy_target): Don't set to_create_inferior or to_supports_non_stop. * target.h (struct target_ops) <to_attach>: Add comment. Remove TARGET_DEFAULT_FUNC. <to_create_inferior>: Add comment. <to_can_async_p, to_is_async_p, to_supports_non_stop>: Use TARGET_DEFAULT_RETURN. <to_can_async_p, to_supports_non_stop, to_can_run>: Add comments. (find_attach_target, find_run_target): Declare. (target_create_inferior): Remove. (target_has_execution_1): Update comment. (target_supports_non_stop): Remove. * target-delegates.c: Rebuild. 2014-03-12 Tom Tromey <tromey@redhat.com> * gdb.base/corefile.exp (corefile_test_run, corefile_test_attach): New procs. Add target-async tests. * gdb.reverse/break-precsave.exp (precsave_tests): New proc. Add target-async tests.
2014-03-06Change the default implementation of to_traceframe_info to tcomplainYao Qi1-1/+1
This patch is to change the default implementation of to_traceframe_info from 'return NULL' to tcomplain, which is intended. If new target supports tracepoint, this method should be implemented, otherwise, an error is thrown. gdb: 2014-03-06 Yao Qi <yao@codesourcery.com> * target.h (struct target_ops) <to_traceframe_info>: Use TARGET_DEFAULT_NORETURN (tcomplain ()). * target-delegates.c: Regenerated.
2014-02-19convert to_get_unwinder and to_get_tailcall_unwinder to methodsTom Tromey1-0/+32
This converts to_get_unwinder and to_get_tailcall_unwinder to methods and arranges for them to use the new delegation scheme. This just lets us avoid having a differing style (neither new-style nor INHERIT) of delegation in the tree. 2014-02-19 Tom Tromey <tromey@redhat.com> * target.c (target_get_unwinder): Rewrite. (target_get_tailcall_unwinder): Rewrite. * record-btrace.c (record_btrace_to_get_unwinder): New function. (record_btrace_to_get_tailcall_unwinder): New function. (init_record_btrace_ops): Update. * target.h (struct target_ops) <to_get_unwinder, to_get_tailcall_unwinder>: Now function pointers. Use TARGET_DEFAULT_RETURN.
2014-02-19convert to_decr_pc_after_breakTom Tromey1-0/+10
This converts to_decr_pc_after_break to the new style of delegation, removing forward_target_decr_pc_after_break. 2014-02-19 Tom Tromey <tromey@redhat.com> * record-btrace.c (record_btrace_decr_pc_after_break): Delegate directly. * target-delegates.c: Rebuild. * target.h (struct target_ops) <to_decr_pc_after_break>: Use TARGET_DEFAULT_FUNC. * target.c (default_target_decr_pc_after_break): Rename from forward_target_decr_pc_after_break. Simplify. (target_decr_pc_after_break): Rely on delegation.
2014-02-19pass NULL to TARGET_DEFAULT_RETURN when appropriateTom Tromey1-7/+7
This changes instances of TARGET_DEFAULT_RETURN(0) to TARGET_DEFAULT_RETURN(NULL) when appropriate. The use of "0" was a relic from an earlier implementation of make-target-delegates; and I didn't want to go back through the long patch series, fixing up conflicts, just to change this small detail. 2014-02-19 Tom Tromey <tromey@redhat.com> * target-delegates.c: Rebuild. * target.h (struct target_ops) <to_extra_thread_info, to_thread_name, to_pid_to_exec_file, to_get_section_table, to_memory_map, to_read_description, to_traceframe_info>: Use NULL, not 0, in TARGET_DEFAULT_RETURN.
2014-02-19change delegation for to_read_descriptionTom Tromey1-0/+16
This switches to_read_description to the "new normal" delegation scheme. This one was a bit trickier than the other changes due to the way that target_read_description handled delegation. I examined all the target implementations of to_read_description and changed the ones returning NULL to instead delegate. 2014-02-19 Tom Tromey <tromey@redhat.com> * arm-linux-nat.c (arm_linux_read_description): Delegate when needed. * corelow.c (core_read_description): Delegate when needed. * remote.c (remote_read_description): Delegate when needed. * target-delegates.c: Rebuild. * target.c (target_read_description): Rewrite. * target.h (struct target_ops) <to_read_description>: Update comment. Use TARGET_DEFAULT_RETURN.