The record btrace target does not allow accessing memory and storing registers
while replaying. For multi-threaded applications, this prevents those
accesses also for threads that are at the end of their execution history as
long as at least one thread is replaying.
Change this to only check if the selected thread is replaying. This allows
threads that are at the end of their execution history to read and write
memory and to store registers.
Also change the error message to reflect this change.
gdb/
* record-btrace.c (record_btrace_xfer_partial)
(record_btrace_store_registers, record_btrace_prepare_to_store):
Call record_btrace_is_replaying with inferior_ptid instead of
minus_one_ptid.
(record_btrace_store_registers): Change error message.
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.
The record btrace target runs synchronous with GDB. That is, GDB steps
resumed threads in record btrace's to_wait method. Without GDB calling
to_wait, nothing happens 'on the target'.
Check for further expected events in to_wait before reporting the current
event and mark record btrace's async event handler in async mode.
gdb/
* record-btrace.c (record_btrace_maybe_mark_async_event): New.
(record_btrace_wait): Call record_btrace_maybe_mark_async_event.
Get_current_frame uses inferior_ptid. In record_btrace_start_replaying,
we need to get the current frame of the argument thread. So far, this
has always been inferior_ptid. With non-stop, this is not guaranteed.
Temporarily set inferior_ptid to the ptid of the argument thread.
We already temporarily set the argument thread's executing flag to false.
Move both into a new function get_thread_current_frame that does the temporary
adjustments, calls get_current_frame, and restores the previous values.
gdb/
* record-btrace.c (get_thread_current_frame): New.
(record_btrace_start_replaying): Call get_thread_current_frame.
The record targets are implicitly schedlocked. They only step the current
thread and keep other threads where they are.
Change record btrace to step all requested threads in to_resume.
For maintenance and debugging, we keep the old behaviour when the target below
is not non-stop. Enable with "maint set target-non-stop on".
gdb/
* record-btrace.c (record_btrace_resume_thread): A move request
overwrites a previous move request.
(record_btrace_find_resume_thread): Removed.
(record_btrace_resume): Resume all requested threads.
Record btrace's to_wait method picks a single thread to step. When passed
minus_one_ptid, it picks the current thread. All other threads remain where
they are.
Change this to step all resumed threads together, one step at a time, until
the first thread reports an event.
We do delay reporting NO_HISTORY events until there are no other events to
report to prevent threads at the end of their execution history from starving
other threads.
We keep threads at the end of their execution history moving and replaying
until we announce their stop in to_wait. This shouldn't really be user-visible
but its a detail worth mentioning.
Since record btrace's to_resume method also picks only a single thread to
resume, there shouldn't be a difference with the current all-stop.
With non-stop or all-stop on top of non-stop, we will see differences. The
behaviour should be more natural as we're moving all threads.
gdb/
* record-btrace.c: Include vec.h.
(record_btrace_find_thread_to_move): Removed.
(btrace_step_no_resumed, btrace_step_again)
(record_btrace_stop_replaying_at_end): New.
(record_btrace_cancel_resume): Call record_btrace_stop_replaying_at_end.
(record_btrace_single_step_forward): Remove calls to
record_btrace_stop_replaying.
(record_btrace_step_thread): Do only one step for BTHR_CONT and
BTHR_RCONT. Keep threads at the end of their history moving.
(record_btrace_wait): Call record_btrace_step_thread for all threads
until one reports an event. Call record_btrace_stop_replaying_at_end
for the eventing thread.
If a single-step ended right at the end of the execution history, we forgot
to announce that. Fix it.
gdb/
* record-btrace.c (record_btrace_single_step_forward): Return
NO_HISTORY if a step brings us to the end of the execution history.
Breakpoints are only checked for BTHR_CONT and BTHR_RCONT stepping requests.
A BTHR_STEP and BTHR_RSTEP request will always report stopped without reason.
Since breakpoints are reported correctly, I assume infrun is handling this.
Move the breakpoint check into the btrace single stepping functions. This
will cause us to report breakpoint hits now also for single-step requests.
One thing to notice is that
- when executing forwards, the breakpoint is checked before 'executing'
the instruction, i.e. before moving the PC to the next instruction.
- when executing backwards, the breakpoint is checked after 'executing'
the instruction, i.e. after moving the PC to the preceding instruction
in the recorded execution.
There is code in infrun (see, for example proceed and adjust_pc_after_break)
that handles this and also depends on this behaviour.
gdb/
* record-btrace.c (record_btrace_step_thread): Move breakpoint check
to ...
(record_btrace_single_step_forward): ... here and
(record_btrace_single_step_backward): ... here.
The code for BTHR_STEP and BTHR_CONT is fairly similar. Extract the common
parts into a new function record_btrace_single_step_forward. The function
returns TARGET_WAITKIND_SPURIOUS to indicate that the single-step completed
without triggering a trap.
Same for BTHR_RSTEP and BTHR_RCONT.
gdb/
* record-btrace.c (btrace_step_spurious)
(record_btrace_single_step_forward)
(record_btrace_single_step_backward): New.
(record_btrace_step_thread): Call record_btrace_single_step_forward
and record_btrace_single_step_backward.
There are two places where record_btrace_step_thread checks for a breakpoint
at the current replay position. Move this code into its own function.
gdb/
* record-btrace.c (record_btrace_replay_at_breakpoint): New.
(record_btrace_step_thread): Call record_btrace_replay_at_breakpoint.
Add support for the to_stop target method to the btrace record target.
gdb/
* btrace.h (enum btrace_thread_flag) <BTHR_STOP>: New.
* record-btrace (record_btrace_resume_thread): Clear BTHR_STOP.
(record_btrace_find_thread_to_move): Also accept threads that have
BTHR_STOP set.
(btrace_step_stopped_on_request, record_btrace_stop): New.
(record_btrace_step_thread): Support BTHR_STOP.
(record_btrace_wait): Also clear BTHR_STOP when stopping other threads.
(init_record_btrace_ops): Initialize to_stop.
The record btrace target stops other threads in non-stop mode after stepping
the to-be-resumed thread.
The check is done on the non_stop variable. It should rather be done on
target_is_non_stop_p (). With all-stop on top of non-stop, infrun will
take care of stopping other threads.
gdb/
* record-btrace.c (record_btrace_wait): Replace non_stop check with
target_is_non_stop_p ().
Indicate speculatively executed instructions with a leading '?'. We use the
space that is normally used for the PC prefix. In the case where the
instruction at the current PC had been executed speculatively before, the PC
prefix will be partially overwritten resulting in "?> ".
As a side-effect, the /p modifier to omit the PC prefix in the "record
instruction-history" command now uses a 3-space PC prefix " " in order to
have enough space for the speculative execution indication.
gdb/
* btrace.c (btrace_compute_ftrace_bts): Clear insn flags.
(pt_btrace_insn_flags): New.
(ftrace_add_pt): Call pt_btrace_insn_flags.
* btrace.h (btrace_insn_flag): New.
(btrace_insn) <flags>: New.
* record-btrace.c (btrace_insn_history): Print insn prefix.
* NEWS: Announce it.
doc/
* gdb.texinfo (Process Record and Replay): Document prefixing of
speculatively executed instructions in the "record instruction-history"
command.
testsuite/
* gdb.btrace/instruction_history.exp: Update.
* gdb.btrace/tsx.exp: New.
* gdb.btrace/tsx.c: New.
* lib/gdb.exp (skip_tsx_tests, skip_btrace_pt_tests): New.
When navigating in the recorded execution trace via "record goto", we do not
set stop_pc. This may trigger an internal error in infrun.c when stepping
from that location. Set it.
(gdb) rec full
(gdb) c
Continuing.
Breakpoint 1, foo (void) at foo.c:42
42 x = y
(gdb) rn
foo (void)
at foo.c:41
41 y = x
(gdb) rec go end
Go forward to insn number 98724
at foo.c:42
42 x = y
(gdb) n
infrun.c:2382: internal-error: resume: Assertion `sig != GDB_SIGNAL_0' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
This happens because there's a breakpoint at PC when the "next"
is issued, so that breapoint should be immediately stepped over.
That should have been detected/done by proceed, here:
if (addr == (CORE_ADDR) -1)
{
if (pc == stop_pc
&& breakpoint_here_p (aspace, pc) == ordinary_breakpoint_here
&& execution_direction != EXEC_REVERSE)
/* There is a breakpoint at the address we will resume at,
step one instruction before inserting breakpoints so that
we do not stop right away (and report a second hit at this
breakpoint).
Note, we don't do this in reverse, because we won't
actually be executing the breakpoint insn anyway.
We'll be (un-)executing the previous instruction. */
tp->stepping_over_breakpoint = 1;
But since stop_pc was stale, the pc == stop_pc check failed, and left the
breakpont at PC inserted.
gdb/
* record-btrace.c (record_btrace_goto_begin, record_btrace_goto_end)
record_btrace_goto): Move call to print_stack_frame ...
(record_btrace_set_replay): ... here. Set stop_pc.
* record-full.c (record_full_goto_entry): Set stop_pc.
testsuite/
* gdb.btrace/record_goto-step.exp: New.
Adds a new command "record btrace pt" to configure the kernel to use
Intel(R) Processor Trace instead of Branch Trace Strore.
The "record btrace" command chooses the tracing format automatically.
Intel(R) Processor Trace support requires Linux 4.1 and libipt.
gdb/
* NEWS: Announce new commands "record btrace pt" and "record pt".
Announce new options "set|show record btrace pt buffer-size".
* btrace.c: Include "rsp-low.h".
Include "inttypes.h".
(btrace_add_pc): Add forward declaration.
(pt_reclassify_insn, ftrace_add_pt, btrace_pt_readmem_callback)
(pt_translate_cpu_vendor, btrace_finalize_ftrace_pt)
(btrace_compute_ftrace_pt): New.
(btrace_compute_ftrace): Support BTRACE_FORMAT_PT.
(check_xml_btrace_version): Update version check.
(parse_xml_raw, parse_xml_btrace_pt_config_cpu)
(parse_xml_btrace_pt_raw, parse_xml_btrace_pt)
(btrace_pt_config_cpu_attributes, btrace_pt_config_children)
(btrace_pt_children): New.
(btrace_children): Add support for "pt".
(parse_xml_btrace_conf_pt, btrace_conf_pt_attributes): New.
(btrace_conf_children): Add support for "pt".
* btrace.h: Include "intel-pt.h".
(btrace_pt_error): New.
* common/btrace-common.c (btrace_format_string, btrace_data_fini)
(btrace_data_empty): Support BTRACE_FORMAT_PT.
* common/btrace-common.h (btrace_format): Add BTRACE_FORMAT_PT.
(struct btrace_config_pt): New.
(struct btrace_config)<pt>: New.
(struct btrace_data_pt_config, struct btrace_data_pt): New.
(struct btrace_data)<pt>: New.
* features/btrace-conf.dtd (btrace-conf)<pt>: New.
(pt): New.
* features/btrace.dtd (btrace)<pt>: New.
(pt, pt-config, cpu): New.
* nat/linux-btrace.c (perf_event_read, perf_event_read_all)
(perf_event_pt_event_type, kernel_supports_pt)
(linux_supports_pt): New.
(linux_supports_btrace): Support BTRACE_FORMAT_PT.
(linux_enable_bts): Free tinfo on error.
(linux_enable_pt): New.
(linux_enable_btrace): Support BTRACE_FORMAT_PT.
(linux_disable_pt): New.
(linux_disable_btrace): Support BTRACE_FORMAT_PT.
(linux_fill_btrace_pt_config, linux_read_pt): New.
(linux_read_btrace): Support BTRACE_FORMAT_PT.
* nat/linux-btrace.h (struct btrace_tinfo_pt): New.
(struct btrace_target_info)<pt>: New.
* record-btrace.c (set_record_btrace_pt_cmdlist)
(show_record_btrace_pt_cmdlist): New.
(record_btrace_print_pt_conf): New.
(record_btrace_print_conf): Support BTRACE_FORMAT_PT.
(btrace_ui_out_decode_error): Support BTRACE_FORMAT_PT.
(cmd_record_btrace_pt_start): New.
(cmd_record_btrace_start): Support BTRACE_FORMAT_PT.
(cmd_set_record_btrace_pt, cmd_show_record_btrace_pt): New.
(_initialize_record_btrace): Add new commands.
* remote.c (PACKET_Qbtrace_pt, PACKET_Qbtrace_conf_pt_size): New.
(remote_protocol_features): Add "Qbtrace:pt".
Add "Qbtrace-conf:pt:size".
(remote_supports_btrace): Support BTRACE_FORMAT_PT.
(btrace_sync_conf): Support PACKET_Qbtrace_conf_pt_size.
(remote_enable_btrace): Support BTRACE_FORMAT_PT.
(_initialize_remote): Add new commands.
gdbserver/
* linux-low.c: Include "rsp-low.h"
(linux_low_encode_pt_config, linux_low_encode_raw): New.
(linux_low_read_btrace): Support BTRACE_FORMAT_PT.
(linux_low_btrace_conf): Support BTRACE_FORMAT_PT.
(handle_btrace_enable_pt): New.
(handle_btrace_general_set): Support "pt".
(handle_btrace_conf_general_set): Support "pt:size".
doc/
* gdb.texinfo (Process Record and Replay): Spell out that variables
and registers are not available during btrace replay.
Describe the new "record btrace pt" command.
Describe the new "set|show record btrace pt buffer-size" options.
(General Query Packets): Describe the new Qbtrace:pt and
Qbtrace-conf:pt:size packets.
Expand "bts" to "Branch Trace Store".
Update the branch trace DTD.
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.
All these were caught by actually making TRY/CATCH use try/catch
behind the scenes, which then resulted in the build failing (on x86_64
Fedora 20) because there was code between the try and catch blocks.
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* breakpoint.c (save_breakpoints): Adjust to avoid code between
TRY and CATCH.
* gdbtypes.c (safe_parse_type): Remove empty line.
(types_deeply_equal):
* guile/scm-frame.c (gdbscm_frame_name):
* linux-thread-db.c (find_new_threads_once):
* python/py-breakpoint.c (bppy_get_commands):
* record-btrace.c (record_btrace_insert_breakpoint)
(record_btrace_remove_breakpoint, record_btrace_start_replaying)
(record_btrace_start_replaying): Adjust to avoid code between TRY
and CATCH.
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
This adjusts the record targets to tell the core whether a trap was
caused by a breakpoint. Targets that can do this should report
breakpoint traps with the PC already adjusted, so this removes the
re-incrementing record-full was doing.
These targets need to be adjusted before process_stratum targets
beneath are, otherwise target_supports_stopped_by_sw_breakpoint,
etc. would fall through to the target beneath while
recording/replaying, and the core would get confused.
Tested on x86-64 Fedora 20, native and gdbserver.
gdb/ChangeLog:
2015-03-04 Pedro Alves <palves@redhat.com>
* btrace.h: Include target/waitstatus.h.
(struct btrace_thread_info) <stop_reason>: New field.
* record-btrace.c (record_btrace_step_thread): Use
record_check_stopped_by_breakpoint instead of breakpoint_here_p.
(record_btrace_decr_pc_after_break): Delete.
(record_btrace_stopped_by_sw_breakpoint)
(record_btrace_supports_stopped_by_sw_breakpoint)
(record_btrace_stopped_by_hw_breakpoint)
(record_btrace_supports_stopped_by_hw_breakpoint): New functions.
(init_record_btrace_ops): Install them.
* record-full.c (record_full_hw_watchpoint): Delete and replace
with ...
(record_full_stop_reason): ... this throughout.
(record_full_exec_insn): Adjust.
(record_full_wait_1): Adjust. No longer re-increment the PC.
(record_full_wait_1): Adjust. Use
record_check_stopped_by_breakpoint instead of breakpoint_here_p.
(record_full_stopped_by_watchpoint): Adjust.
(record_full_stopped_by_sw_breakpoint)
(record_full_supports_stopped_by_sw_breakpoint)
(record_full_supports_stopped_by_sw_breakpoint)
(record_full_stopped_by_hw_breakpoint)
(record_full_supports_stopped_by_hw_breakpoint): New functions.
(init_record_full_ops, init_record_full_core_ops): Install them.
* record.c (record_check_stopped_by_breakpoint): New function.
* record.h: Include target/waitstatus.h.
(record_check_stopped_by_breakpoint): New declaration.
The "record function-call-history" command prints the range of source lines
for a function segment when given the /l modifier. This information is
computed for the entire execution history when processing the recorded branch
trace.
To speed up the initial trace processing, we compute the information when
we print a function segment and only if requested. The computation is fast
enough (due to the limited scope) that it is not worth storing the data in
struct btrace_function, anymore.
gdb/
* btrace.h (btrace_function) <lbegin, lend>: Remove.
* btrace.c (ftrace_debug): Do not print the line range.
(ftrace_skip_file, ftrace_update_lines): Remove.
(ftrace_new_function): Remove lbegin and lend initialization.
(btrace_compute_ftrace_bts): Remove call to ftrace_update_lines.
* record-btrace.c (btrace_compute_src_line_range): New.
(btrace_call_history_src_line): Call btrace_compute_src_line_range.
The set_record_btrace_cmdlist and show_record_btrace_cmdlist objects
are declared twice in the file, seemingly a simply copy/paste
oversight. In C, the first time counts as forward declaration, but in
C++, they are all definitions. That results in:
src/gdb/record-btrace.c:80:33: error: redefinition of ‘cmd_list_element* set_record_btrace_cmdlist’
src/gdb/record-btrace.c:61:33: error: ‘cmd_list_element* set_record_btrace_cmdlist’ previously declared here
src/gdb/record-btrace.c:81:33: error: redefinition of ‘cmd_list_element* show_record_btrace_cmdlist’
src/gdb/record-btrace.c:62:33: error: ‘cmd_list_element* show_record_btrace_cmdlist’ previously declared here
gdb/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* record-btrace.c (set_record_btrace_cmdlist)
(show_record_btrace_cmdlist): Remove redefinitions.
---
gdb/record-btrace.c | 4 ----
1 file changed, 4 deletions(-)
Indicate gaps in the trace due to decode errors. Internally, a gap is
represented as a btrace function segment without instructions and with a
non-zero format-specific error code.
Show the gap when traversing the instruction or function call history.
Also indicate gaps in "info record".
It looks like this:
(gdb) info record
Active record target: record-btrace
Recording format: Branch Trace Store.
Buffer size: 64KB.
Recorded 32 instructions in 5 functions (1 gaps) for thread 1 (process 7182).
(gdb) record function-call-history /cli
1 fib inst 1,9 at src/fib.c:9,14
2 fib inst 10,20 at src/fib.c:6,14
3 [decode error (1): instruction overflow]
4 fib inst 21,28 at src/fib.c:11,14
5 fib inst 29,33 at src/fib.c:6,9
(gdb) record instruction-history 20,22
20 0x000000000040062f <fib+47>: sub $0x1,%rax
[decode error (1): instruction overflow]
21 0x0000000000400613 <fib+19>: add $0x1,%rax
22 0x0000000000400617 <fib+23>: mov %rax,0x200a3a(%rip)
(gdb)
Gaps are ignored during reverse execution and replay.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* btrace.c (ftrace_find_call): Skip gaps.
(ftrace_new_function): Initialize level.
(ftrace_new_call, ftrace_new_tailcall, ftrace_new_return)
(ftrace_new_switch): Update
level computation.
(ftrace_new_gap): New.
(ftrace_update_function): Create new function after gap.
(btrace_compute_ftrace_bts): Create gap on error.
(btrace_stitch_bts): Update parameters. Clear trace if it
becomes empty.
(btrace_stitch_trace): Update parameters. Update callers.
(btrace_clear): Reset the number of gaps.
(btrace_insn_get): Return NULL if the iterator points to a gap.
(btrace_insn_number): Return zero if the iterator points to a gap.
(btrace_insn_end): Allow gaps at the end.
(btrace_insn_next, btrace_insn_prev, btrace_insn_cmp): Handle gaps.
(btrace_find_insn_by_number): Assert that the found iterator does
not point to a gap.
(btrace_call_next, btrace_call_prev): Assert that the last function
is not a gap.
* btrace.h (btrace_bts_error): New.
(btrace_function): Update comment.
(btrace_function) <insn, insn_offset, number>: Update comment.
(btrace_function) <errcode>: New.
(btrace_thread_info) <ngaps>: New.
(btrace_thread_info) <replay>: Update comment.
(btrace_insn_get): Update comment.
* record-btrace.c (btrace_ui_out_decode_error): New.
(record_btrace_info): Print number of gaps.
(btrace_insn_history, btrace_call_history): Call
btrace_ui_out_decode_error for gaps.
(record_btrace_step_thread, record_btrace_start_replaying): Skip gaps.
testsuite/
* gdb.btrace/buffer-size.exp: Update "info record" output.
* 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.
Allow the size of the branch trace ring buffer to be defined by the
user. The specified buffer size will be used when BTS tracing is
enabled for new threads.
The obtained buffer size may differ from the requested size. The
actual buffer size for the current thread is shown in the "info record"
command.
Bigger buffers mean longer traces, but also longer processing time.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* btrace.c (parse_xml_btrace_conf_bts): Add size.
(btrace_conf_bts_attributes): New.
(btrace_conf_children): Add attributes.
* common/btrace-common.h (btrace_config_bts): New.
(btrace_config)<bts>: New.
(btrace_config): Update comment.
* nat/linux-btrace.c (linux_enable_btrace, linux_enable_bts):
Use config.
* features/btrace-conf.dtd: Increment version. Add size
attribute to bts element.
* record-btrace.c (set_record_btrace_bts_cmdlist,
show_record_btrace_bts_cmdlist): New.
(record_btrace_adjust_size, record_btrace_print_bts_conf,
record_btrace_print_conf, cmd_set_record_btrace_bts,
cmd_show_record_btrace_bts): New.
(record_btrace_info): Call record_btrace_print_conf.
(_initialize_record_btrace): Add commands.
* remote.c: Add PACKET_Qbtrace_conf_bts_size enum.
(remote_protocol_features): Add Qbtrace-conf:bts:size packet.
(btrace_sync_conf): Synchronize bts size.
(_initialize_remote): Add Qbtrace-conf:bts:size packet.
* NEWS: Announce new commands and new packets.
doc/
* gdb.texinfo (Branch Trace Configuration Format): Add size.
(Process Record and Replay): Describe new set|show commands.
(General Query Packets): Describe Qbtrace-conf:bts:size packet.
testsuite/
* gdb.btrace/buffer-size: New.
gdbserver/
* linux-low.c (linux_low_btrace_conf): Print size.
* server.c (handle_btrace_conf_general_set): New.
(hanle_general_set): Call handle_btrace_conf_general_set.
(handle_query): Report Qbtrace-conf:bts:size as supported.
Add a struct to describe the branch trace configuration and use it for
enabling branch tracing.
The user will be able to set configuration fields for each tracing format
to be used for new threads.
The actual configuration that is active for a given thread will be shown
in the "info record" command.
At the moment, the configuration struct only contains a format field
that is set to the only available format.
The format is the only configuration option that can not be set via set
commands. It is given as argument to the "record btrace" command when
starting recording.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* Makefile.in (XMLFILES): Add btrace-conf.dtd.
* x86-linux-nat.c (x86_linux_enable_btrace): Update parameters.
(x86_linux_btrace_conf): New.
(x86_linux_create_target): Initialize to_btrace_conf.
* nat/linux-btrace.c (linux_enable_btrace): Update parameters.
Check format. Split into this and ...
(linux_enable_bts): ... this.
(linux_btrace_conf): New.
(perf_event_skip_record): Renamed into ...
(perf_event_skip_bts_record): ... this. Updated users.
(linux_disable_btrace): Split into this and ...
(linux_disable_bts): ... this.
(linux_read_btrace): Check format.
* nat/linux-btrace.h (linux_enable_btrace): Update parameters.
(linux_btrace_conf): New.
(btrace_target_info)<ptid>: Moved.
(btrace_target_info)<conf>: New.
(btrace_target_info): Split into this and ...
(btrace_tinfo_bts): ... this. Updated users.
* btrace.c (btrace_enable): Update parameters.
(btrace_conf, parse_xml_btrace_conf_bts, parse_xml_btrace_conf)
(btrace_conf_children, btrace_conf_attributes)
(btrace_conf_elements): New.
* btrace.h (btrace_enable): Update parameters.
(btrace_conf, parse_xml_btrace_conf): New.
* common/btrace-common.h (btrace_config): New.
* feature/btrace-conf.dtd: New.
* record-btrace.c (record_btrace_conf): New.
(record_btrace_cmdlist): New.
(record_btrace_enable_warn, record_btrace_open): Pass
&record_btrace_conf.
(record_btrace_info): Print recording format.
(cmd_record_btrace_bts_start): New.
(cmd_record_btrace_start): Call cmd_record_btrace_bts_start.
(_initialize_record_btrace): Add "record btrace bts" subcommand.
Add "record bts" alias command.
* remote.c (remote_state)<btrace_config>: New.
(remote_btrace_reset, PACKET_qXfer_btrace_conf): New.
(remote_protocol_features): Add qXfer:btrace-conf:read.
(remote_open_1): Call remote_btrace_reset.
(remote_xfer_partial): Handle TARGET_OBJECT_BTRACE_CONF.
(btrace_target_info)<conf>: New.
(btrace_sync_conf, btrace_read_config): New.
(remote_enable_btrace): Update parameters. Call btrace_sync_conf and
btrace_read_conf.
(remote_btrace_conf): New.
(init_remote_ops): Initialize to_btrace_conf.
(_initialize_remote): Add qXfer:btrace-conf packet.
* target.c (target_enable_btrace): Update parameters.
(target_btrace_conf): New.
* target.h (target_enable_btrace): Update parameters.
(target_btrace_conf): New.
(target_object)<TARGET_OBJECT_BTRACE_CONF>: New.
(target_ops)<to_enable_btrace>: Update parameters and comment.
(target_ops)<to_btrace_conf>: New.
* target-delegates: Regenerate.
* target-debug.h (target_debug_print_const_struct_btrace_config_p)
(target_debug_print_const_struct_btrace_target_info_p): New.
NEWS: Announce new command and new packet.
doc/
* gdb.texinfo (Process Record and Replay): Describe the "record
btrace bts" command.
(General Query Packets): Describe qXfer:btrace-conf:read packet.
(Branch Trace Configuration Format): New.
gdbserver/
* linux-low.c (linux_low_enable_btrace): Update parameters.
(linux_low_btrace_conf): New.
(linux_target_ops)<to_btrace_conf>: Initialize.
* server.c (current_btrace_conf): New.
(handle_btrace_enable): Rename to ...
(handle_btrace_enable_bts): ... this. Pass ¤t_btrace_conf
to target_enable_btrace. Update comment. Update users.
(handle_qxfer_btrace_conf): New.
(qxfer_packets): Add btrace-conf entry.
(handle_query): Report qXfer:btrace-conf:read as supported packet.
* target.h (target_ops)<enable_btrace>: Update parameters and comment.
(target_ops)<read_btrace_conf>: New.
(target_enable_btrace): Update parameters.
(target_read_btrace_conf): New.
testsuite/
* gdb.btrace/delta.exp: Update "info record" output.
* gdb.btrace/enable.exp: Update "info record" output.
* gdb.btrace/finish.exp: Update "info record" output.
* gdb.btrace/instruction_history.exp: Update "info record" output.
* gdb.btrace/next.exp: Update "info record" output.
* gdb.btrace/nexti.exp: Update "info record" output.
* gdb.btrace/step.exp: Update "info record" output.
* gdb.btrace/stepi.exp: Update "info record" output.
* gdb.btrace/nohist.exp: Update "info record" output.
Add a format argument to the various supports_btrace functions to check
for support of a specific btrace format. This is to prepare for a new
format.
Removed two redundant calls. The check will be made in the subsequent
btrace_enable call.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* btrace.c (btrace_enable): Pass BTRACE_FORMAT_BTS.
* record-btrace.c (record_btrace_open): Remove call to
target_supports_btrace.
* remote.c (remote_supports_btrace): Update parameters.
* target.c (target_supports_btrace): Update parameters.
* target.h (to_supports_btrace, target_supports_btrace): Update
parameters.
* target-delegates.c: Regenerate.
* target-debug.h (target_debug_print_enum_btrace_format): New.
* nat/linux-btrace.c
(kernel_supports_btrace): Rename into ...
(kernel_supports_bts): ... this. Update users. Update warning text.
(intel_supports_btrace): Rename into ...
(intel_supports_bts): ... this. Update users.
(cpu_supports_btrace): Rename into ...
(cpu_supports_bts): ... this. Update users.
(linux_supports_btrace): Update parameters. Split into this and ...
(linux_supports_bts): ... this.
* nat/linux-btrace.h (linux_supports_btrace): Update parameters.
gdbserver/
* server.c (handle_btrace_general_set): Remove call to
target_supports_btrace.
(supported_btrace_packets): New.
(handle_query): Call supported_btrace_packets.
* target.h: include btrace-common.h.
(btrace_target_info): Removed.
(supports_btrace, target_supports_btrace): Update parameters.
The sigall-reverse.exp test occasionally fails with something like this:
(gdb) PASS: gdb.reverse/sigall-reverse.exp: send signal TERM
continue
Continuing.
The next instruction is syscall exit_group. It will make the program exit. Do you want to stop the program?([y] or n) FAIL: gdb.reverse/sigall-reverse.exp: continue to signal exit (timeout)
FAIL: gdb.reverse/sigall-reverse.exp: reverse to handler of TERM (timeout)
FAIL: gdb.reverse/sigall-reverse.exp: reverse to gen_TERM (timeout)
This is another event-loop/async related problem exposed by the patch
that made 'query' use gdb_readline_wrapper (588dcc3edb).
The problem is that even though gdb_readline_wrapper disables
target-async while the secondary prompt is in progress, the record
target's async event source is left marked. So when
gdb_readline_wrapper nests an event loop to process input, it may
happen that that event loop ends up processing a target event while
GDB is not really ready for it. Here's the relevant part of the
backtrace showing the root issue in action:
...
#14 0x000000000061cb48 in fetch_inferior_event (client_data=0x0) at src/gdb/infrun.c:4158
#15 0x0000000000642917 in inferior_event_handler (event_type=INF_REG_EVENT, client_data=0x0) at src/gdb/inf-loop.c:57
#16 0x000000000077ca5c in record_full_async_inferior_event_handler (data=0x0) at src/gdb/record-full.c:791
#17 0x0000000000640fdf in invoke_async_event_handler (data=...) at src/gdb/event-loop.c:1067
#18 0x000000000063fb01 in process_event () at src/gdb/event-loop.c:339
#19 0x000000000063fb2a in gdb_do_one_event () at src/gdb/event-loop.c:360
#20 0x000000000074d607 in gdb_readline_wrapper (prompt=0x3588f40 "The next instruction is syscall exit_group. It will make the program exit. Do you want to stop the program?([y] or n) ") at src/gdb/top.c:842
#21 0x0000000000750bd9 in defaulted_query (ctlstr=0x8c6588 "The next instruction is syscall exit_group. It will make the program exit. Do you want to stop the program?", defchar=121 'y', args=0x7fff70524410) at src/gdb/utils.c:1279
#22 0x0000000000750e4c in yquery (ctlstr=0x8c6588 "The next instruction is syscall exit_group. It will make the program exit. Do you want to stop the program?") at src/gdb/utils.c:1358
#23 0x00000000004b020e in record_linux_system_call (syscall=gdb_sys_exit_group, regcache=0x3529450, tdep=0xd6c840 <amd64_linux_record_tdep>) at src/gdb/linux-record.c:1933
With my all-stop-on-top-of-non-stop series, I'm also seeing
gdb.server/ext-attach.exp fail occasionally due to the same issue.
The first part of the fix is for target_async implementations to make
sure to remove/unmark all target-related event sources from the event
loop.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/
2015-02-03 Pedro Alves <palves@redhat.com>
* event-loop.c (clear_async_event_handler): New function.
* event-loop.h (clear_async_event_handler): New declaration.
* record-btrace.c (record_btrace_async): New function.
(init_record_btrace_ops): Install record_btrace_async.
* record-full.c (record_full_async): New function.
(record_full_resume): Don't mark the async event source here.
(init_record_full_ops): Install record_full_async.
(record_full_core_resume): Don't mark the async event source here.
(init_record_full_core_ops): Install record_full_async.
* remote.c (remote_async): Mark and clear the async stop reply
queue event-loop token as appropriate.
This patch introduces find_inferior_ptid to replace the common idiom
find_inferior_pid (ptid_get_pid (...));
It replaces all the instances of that idiom that I found with the new
function.
No significant changes before/after the patch in the regression suite
on amd64 linux.
gdb/ChangeLog:
* inferior.c (find_inferior_ptid): New function.
* inferior.h (find_inferior_ptid): New declaration.
* ada-tasks.c (ada_get_task_number): Use find_inferior_ptid.
* corelow.c (core_pid_to_str): Same.
* darwin-nat.c (darwin_resume): Same.
* infrun.c (fetch_inferior_event): Same.
(get_inferior_stop_soon): Same.
(handle_inferior_event): Same.
(handle_signal_stop): Same.
* linux-nat.c (resume_lwp): Same.
(stop_wait_callback): Same.
* mi/mi-interp.c (mi_new_thread): Same.
(mi_thread_exit): Same.
* proc-service.c (ps_pglobal_lookup): Same.
* record-btrace.c (record_btrace_step_thread): Same.
* remote-sim.c (gdbsim_close_inferior): Same.
(gdbsim_resume): Same.
(gdbsim_stop): Same.
* sol2-tdep.c (sol2_core_pid_to_str): Same.
* target.c (memory_xfer_partial_1): Same.
(default_thread_address_space): Same.
* thread.c (thread_change_ptid): Same.
(switch_to_thread): Same.
(do_restore_current_thread_cleanup): Same.
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.
This makes target_ops::to_open take a const string and then fixes the
fallout.
There were a few of these I could not build. However I eyeballed it
and in any case the fixes should generally be trivial.
This is based on the patch to fix up the target debugging for to_open,
because that changes gdb to not directly install to_open as the target
command
2014-07-30 Tom Tromey <tromey@redhat.com>
* bsd-kvm.c (bsd_kvm_open): Constify.
* corelow.c (core_open): Constify.
* ctf.c (ctf_open): Constify.
* dbug-rom.c (dbug_open): Constify.
* exec.c (exec_open): Constify.
* m32r-rom.c (m32r_open, mon2000_open): Constify.
* microblaze-rom.c (picobug_open): Constify.
* nto-procfs.c (procfs_open_1, procfs_open, procfs_native_open):
Constify.
* ppcbug-rom.c (ppcbug_open0, ppcbug_open1): Constify.
* record-btrace.c (record_btrace_open): Constify.
* record-full.c (record_full_core_open_1, record_full_open_1)
(record_full_open): Constify.
* remote-m32r-sdi.c (m32r_open): Constify.
* remote-mips.c (common_open, mips_open, pmon_open, ddb_open)
(rockhopper_open, lsi_open): Constify.
* remote-sim.c (gdbsim_open): Constify.
* remote.c (remote_open, extended_remote_open, remote_open_1):
Constify.
* target.h (struct target_ops) <to_open>: Make "arg" const.
* tracefile-tfile.c (tfile_open): Constify.
This patch cleans up some minor inconsistencies in target delegation.
It's primary purpose is to avoid confusion in the code. A few spots
were checking the "beneath" target; however this can only be NULL for
the dummy target, so such tests are not needed. Some other spots were
iterating over the beneath targets, looking for a method
implementation. This is not needed for methods handled by
make-target-delegates, as there is always an implementation.
2014-07-18 Tom Tromey <tromey@redhat.com>
PR gdb/17130:
* spu-multiarch.c (spu_region_ok_for_hw_watchpoint)
(spu_fetch_registers, spu_store_registers, spu_xfer_partial)
(spu_search_memory, spu_mourn_inferior): Simplify delegation.
* linux-thread-db.c (thread_db_pid_to_str): Always delegate.
* windows-nat.c (windows_xfer_partial): Always delegate.
* record-btrace.c (record_btrace_xfer_partial): Simplify
delegation.
(record_btrace_fetch_registers, record_btrace_store_registers)
(record_btrace_prepare_to_store, record_btrace_resume)
(record_btrace_wait, record_btrace_find_new_threads)
(record_btrace_thread_alive): Likewise.
* procfs.c (procfs_xfer_partial): Always delegate.
* corelow.c (core_xfer_partial): Always delegate.
* sol-thread.c (sol_find_new_threads): Simplify delegation.
When generating a core file using the "generate-core-file" command while
replaying with the btrace record target, we won't be able to access all
registers and all memory. This leads to the following assertion:
gdb/regcache.c:1034: internal-error: regcache_raw_supply: Assertion `regnum >= 0 && regnum < regcache->descr->nr_raw_registers' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: gdb.btrace/gcore.exp: generate-core-file core (GDB internal error)
Resyncing due to internal error.
Pretend that we are not replaying while generating a core file. This will
forward fetch and store registers as well as xfer memory calls to the target
beneath.
gdb/
* record-btrace.c (record_btrace_generating_corefile)
(record_btrace_prepare_to_generate_core)
(record_btrace_done_generating_core): New.
(record_btrace_xfer_partial, record_btrace_fetch_registers)
(record_btrace_store_registers, record_btrace_prepare_to_store):
Forward request when generating a core file.
(record_btrace_open): Set record_btrace_generating_corefile to zero.
(init_record_btrace_ops): Set to_prepare_to_generate_core and
to_done_generating_core.
testsuite/
* gdb.btrace/gcore.exp: New.
Running gdb.threads/thread-execl.exp with scheduler-locking set to
"step" reveals a problem:
(gdb) next^M
[Thread 0x7ffff7fda700 (LWP 27168) exited]^M
[New LWP 27168]^M
[Thread 0x7ffff74ee700 (LWP 27174) exited]^M
process 27168 is executing new program: /home/jkratoch/redhat/gdb-clean/gdb/testsuite/gdb.threads/thread-execl^M
[Thread debugging using libthread_db enabled]^M
Using host libthread_db library "/lib64/libthread_db.so.1".^M
infrun.c:5225: internal-error: switch_back_to_stepped_thread: Assertion `!schedlock_applies (1)' failed.^M
A problem internal to GDB has been detected,^M
further debugging may prove unreliable.^M
Quit this debugging session? (y or n) FAIL: gdb.threads/thread-execl.exp: schedlock step: get to main in new image (GDB internal error)
The assertion is correct. The issue is that GDB is mistakenly trying
to switch back to an exited thread, that was previously stepping when
it exited. This is exactly the sort of thing the test wants to make
sure doesn't happen:
# Now set a breakpoint at `main', and step over the execl call. The
# breakpoint at main should be reached. GDB should not try to revert
# back to the old thread from the old image and resume stepping it
We don't see this bug with schedlock off only because a different
sequence of events makes GDB manage to delete the thread instead of
marking it exited.
This particular internal error can be fixed by making the loop over
all threads in switch_back_to_stepped_thread skip exited threads.
But, looking over other ALL_THREADS users, all either can or should be
skipping exited threads too. So for simplicity, this patch replaces
ALL_THREADS with a new macro that skips exited threads itself, and
updates everything to use it.
Tested on x86_64 Fedora 20.
gdb/
2014-06-19 Pedro Alves <palves@redhat.com>
* gdbthread.h (ALL_THREADS): Delete.
(ALL_NON_EXITED_THREADS): New macro.
* btrace.c (btrace_free_objfile): Use ALL_NON_EXITED_THREADS
instead of ALL_THREADS.
* infrun.c (find_thread_needs_step_over)
(switch_back_to_stepped_thread): Use ALL_NON_EXITED_THREADS
instead of ALL_THREADS.
* record-btrace.c (record_btrace_open)
(record_btrace_stop_recording, record_btrace_close)
(record_btrace_is_replaying, record_btrace_resume)
(record_btrace_find_thread_to_move, record_btrace_wait): Likewise.
* remote.c (append_pending_thread_resumptions): Likewise.
* thread.c (thread_apply_all_command): Likewise.
gdb/testsuite/
2014-06-19 Pedro Alves <palves@redhat.com>
* gdb.threads/thread-execl.exp (do_test): New procedure, factored
out from ...
(top level): ... here. Iterate running tests under different
scheduler-locking settings.
The btrace record target does not trace data. We therefore do not allow
accessing read-write memory during replay.
In some cases, this might be useful to advanced users, though, who we assume
to know what they are doing.
Add a set|show command pair to turn this memory access restriction off.
* record-btrace.c (record_btrace_allow_memory_access): Remove.
(replay_memory_access_read_only, replay_memory_access_read_write)
(replay_memory_access_types, replay_memory_access)
(set_record_btrace_cmdlist, show_record_btrace_cmdlist)
(cmd_set_record_btrace, cmd_show_record_btrace)
(cmd_show_replay_memory_access): New.
(record_btrace_xfer_partial, record_btrace_insert_breakpoint)
(record_btrace_remove_breakpoint): Replace
record_btrace_allow_memory_access with replay_memory_access.
(_initialize_record_btrace): Add commands.
* NEWS: Announce it.
testsuite/
* gdb.btrace/data.exp: Test it.
doc/
* gdb.texinfo (Process Record and Replay): Document it.
Move infrun.c declarations out of inferior.h to a new infrun.h file.
Tested by building on:
i686-w64-mingw32, enable-targets=all
x86_64-linux, enable-targets=all
i586-pc-msdosdjgpp
And also grepped the whole tree for each symbol moved to find where
infrun.h might be necessary.
gdb/
2014-05-22 Pedro Alves <palves@redhat.com>
* inferior.h (debug_infrun, debug_displaced, stop_on_solib_events)
(sync_execution, sched_multi, step_stop_if_no_debug, non_stop)
(disable_randomization, enum exec_direction_kind)
(execution_direction, stop_registers, start_remote)
(clear_proceed_status, proceed, resume, user_visible_resume_ptid)
(wait_for_inferior, normal_stop, get_last_target_status)
(prepare_for_detach, fetch_inferior_event, init_wait_for_inferior)
(insert_step_resume_breakpoint_at_sal)
(follow_inferior_reset_breakpoints, stepping_past_instruction_at)
(set_step_info, print_stop_event, signal_stop_state)
(signal_print_state, signal_pass_state, signal_stop_update)
(signal_print_update, signal_pass_update)
(update_signals_program_target, clear_exit_convenience_vars)
(displaced_step_dump_bytes, update_observer_mode)
(signal_catch_update, gdb_signal_from_command): Move
declarations ...
* infrun.h: ... to this new file.
* amd64-tdep.c: Include infrun.h.
* annotate.c: Include infrun.h.
* arch-utils.c: Include infrun.h.
* arm-linux-tdep.c: Include infrun.h.
* arm-tdep.c: Include infrun.h.
* break-catch-sig.c: Include infrun.h.
* breakpoint.c: Include infrun.h.
* common/agent.c: Include infrun.h instead of inferior.h.
* corelow.c: Include infrun.h.
* event-top.c: Include infrun.h.
* go32-nat.c: Include infrun.h.
* i386-tdep.c: Include infrun.h.
* inf-loop.c: Include infrun.h.
* infcall.c: Include infrun.h.
* infcmd.c: Include infrun.h.
* infrun.c: Include infrun.h.
* linux-fork.c: Include infrun.h.
* linux-nat.c: Include infrun.h.
* linux-thread-db.c: Include infrun.h.
* monitor.c: Include infrun.h.
* nto-tdep.c: Include infrun.h.
* procfs.c: Include infrun.h.
* record-btrace.c: Include infrun.h.
* record-full.c: Include infrun.h.
* remote-m32r-sdi.c: Include infrun.h.
* remote-mips.c: Include infrun.h.
* remote-notif.c: Include infrun.h.
* remote-sim.c: Include infrun.h.
* remote.c: Include infrun.h.
* reverse.c: Include infrun.h.
* rs6000-tdep.c: Include infrun.h.
* s390-linux-tdep.c: Include infrun.h.
* solib-irix.c: Include infrun.h.
* solib-osf.c: Include infrun.h.
* solib-svr4.c: Include infrun.h.
* target.c: Include infrun.h.
* top.c: Include infrun.h.
* windows-nat.c: Include infrun.h.
* mi/mi-interp.c: Include infrun.h.
* mi/mi-main.c: Include infrun.h.
* python/py-threadevent.c: Include infrun.h.
When using a reverse execution command without execution history, GDB
might end up in a state where replaying has been started but remains
at the current instruction. This state is illegal.
Do not step if there is no execution history to avoid this.
2014-05-20 Markus Metzger <markus.t.metzger@intel.com>
* record-btrace.c (record_btrace_step_thread): Check for empty history.
testsuite/
* gdb.btrace/nohist.exp: New.
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.
Nowadays, TARGET_XFER_E_UNAVAILABLE isn't regarded as an error in
to_xfer_partial interface, so _E_ looks odd. This patch is to
replace TARGET_XFER_E_UNAVAILABLE with TARGET_XFER_UNAVAILABLE,
and change its value from -2 to 2. Since there is no comparison
on the value of 'enum target_xfer_status', so it should be safe.
gdb:
2014-02-24 Yao Qi <yao@codesourcery.com>
* target.h (enum target_xfer_status)
<TARGET_XFER_E_UNAVAILABLE>: Rename it to ...
<TARGET_XFER_UNAVAILABLE>: ... it with setting value 2
explicitly. New.
* corefile.c (memory_error_message): User updated.
* exec.c (section_table_read_available_memory): Likewise.
* record-btrace.c (record_btrace_xfer_partial): Likewise.
* target.c (target_xfer_status_to_string): Likewise.
(raw_memory_xfer_partial): Likewise.
(memory_xfer_partial_1, target_xfer_partial): Likewise.
* valops.c (read_value_memory): Likewise.
* exec.h: Update comments.
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.
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.
Markus Metzger
Simon Marchi
Pedro Alves
Joel Brobecker
Doug Evans
Gary Benson
Tom Tromey
Yao Qi