The reverse-finish command results in an internal error if it cannot determine
the current function.
(gdb) c
Continuing.
Program received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()
(gdb) reverse-finish
Run back to call of #0 0x0000000000000000 in ?? ()
gdb/infcmd.c:1576: internal-error: Finish: couldn't find function.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) y
This is not an internal error case since the command may be used in scenarios
where there is no function at the current PC, e.g. after calling through a bad
function pointer.
Turn this into a normal error.
gdb/
* infcmd.c (finish_backward): Turn internal error into normal error.
testsuite/
* gdb.btrace/segv.c: New.
* gdb.btrace/segv.exp: New.
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.
When loading symbols for the vdso, also add its sections to target_sections.
This fixes an issue with record btrace where vdso instructions could not be
disassembled during replay.
* symfile-mem.c (symbol_file_add_from_memory): Add BFD sections.
testsuite/
* gdb.btrace/vdso.c: New.
* gdb.btrace/vdso.exp: New.
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.
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.
Provide to_resume and to_wait target methods for the btrace record target
to allow reverse stepping and replay support.
Replay is limited in the sense that only stepping and source correlation
are supported. We do not record data and thus can not show variables.
Non-stop mode is not working. Do not allow record-btrace in non-stop mode.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* btrace.h (btrace_thread_flag): New.
(struct btrace_thread_info) <flags>: New.
* record-btrace.c (record_btrace_resume_thread)
(record_btrace_find_thread_to_move, btrace_step_no_history)
(btrace_step_stopped, record_btrace_start_replaying)
(record_btrace_step_thread, record_btrace_decr_pc_after_break)
(record_btrace_find_resume_thread): New.
(record_btrace_resume, record_btrace_wait): Extend.
(record_btrace_can_execute_reverse): New.
(record_btrace_open): Fail in non-stop mode.
(record_btrace_set_replay): Split into this, ...
(record_btrace_stop_replaying): ... this, ...
(record_btrace_clear_histories): ... and this.
(init_record_btrace_ops): Init to_can_execute_reverse.
* NEWS: Announce it.
testsuite/
* gdb.btrace/delta.exp: Check reverse stepi.
* gdb.btrace/tailcall.exp: Update. Add stepping tests.
* gdb.btrace/finish.exp: New.
* gdb.btrace/next.exp: New.
* gdb.btrace/nexti.exp: New.
* gdb.btrace/record_goto.c: Add comments.
* gdb.btrace/step.exp: New.
* gdb.btrace/stepi.exp: New.
* gdb.btrace/multi-thread-step.c: New.
* gdb.btrace/multi-thread-step.exp: New.
* gdb.btrace/rn-dl-bind.c: New.
* gdb.btrace/rn-dl-bind.exp: New.
* gdb.btrace/data.c: New.
* gdb.btrace/data.exp: New.
* gdb.btrace/Makefile.in (EXECUTABLES): Add new.
doc/
* gdb.texinfo: Document limited reverse/replay support
for target record-btrace.
The btrace record target shows the branch trace from the location of the first
branch destination. This is the first BTS records.
After adding incremental updates, we can now add a dummy record for the current
PC when we enable tracing so we show the trace from the location where branch
tracing has been enabled.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* btrace.c: Include regcache.h.
(btrace_add_pc): New.
(btrace_enable): Call btrace_add_pc.
(btrace_is_empty): New.
* btrace.h (btrace_is_empty): New.
* record-btrace.c (require_btrace, record_btrace_info): Call
btrace_is_empty.
testsuite/
* gdb.btrace/Makefile.in (EXECUTABLES): Add delta.
* gdb.btrace/exception.exp: Update.
* gdb.btrace/instruction_history.exp: Update.
* gdb.btrace/record_goto.exp: Update.
* gdb.btrace/tailcall.exp: Update.
* gdb.btrace/unknown_functions.exp: Update.
* gdb.btrace/delta.exp: New.
Extend the always failing unwinder to provide the PC based on the call
structure detected in the branch trace.
The unwinder supports normal frames and tailcall frames.
Inline frames are not supported.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* record.h (record_btrace_frame_unwind)
(record_btrace_tailcall_frame_unwind): New declarations.
* dwarf2-frame: Include record.h
(dwarf2_frame_cfa): Throw an error for btrace frames.
* record-btrace.c: Include hashtab.h.
(btrace_get_bfun_name): New.
(btrace_call_history): Call btrace_get_bfun_name.
(struct btrace_frame_cache): New.
(bfcache): New.
(bfcache_hash, bfcache_eq, bfcache_new): New.
(btrace_get_frame_function): New.
(record_btrace_frame_unwind_stop_reason): Allow unwinding.
(record_btrace_frame_this_id): Compute own id.
(record_btrace_frame_prev_register): Provide PC, throw_error
for all other registers.
(record_btrace_frame_sniffer): Detect btrace frames.
(record_btrace_tailcall_frame_sniffer): New.
(record_btrace_frame_dealloc_cache): New.
(record_btrace_frame_unwind): Add new functions.
(record_btrace_tailcall_frame_unwind): New.
(_initialize_record_btrace): Allocate cache.
* btrace.c (btrace_clear): Call reinit_frame_cache.
* NEWS: Announce it.
testsuite/
* gdb.btrace/record_goto.exp: Add backtrace test.
* gdb.btrace/tailcall.exp: Add backtrace test.
The "record function-call-history" and "record instruction-history" commands
accept a range "begin, end". End is not included in both cases. Include it.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* record-btrace.c (record_btrace_insn_history_range): Include
end.
(record_btrace_insn_history_from): Adjust range.
(record_btrace_call_history_range): Include
end.
(record_btrace_call_history_from): Adjust range.
* NEWS: Announce changes.
testsuite/
* gdb.btrace/function_call_history.exp: Update tests.
* gdb.btrace/instruction_history.exp: Update tests.
doc/
* gdb.texinfo (Process Record and Replay): Update documentation.
Add a new modifier /c to the "record function-call-history" command to
indent the function name based on its depth in the call stack.
Also reorder the optional fields to have the indentation at the very beginning.
Prefix the insn range (/i modifier) with "inst ".
Prefix the source line (/l modifier) with "at ".
Change the range syntax from "begin-end" to "begin,end" to allow copy&paste to
the "record instruction-history" and "list" commands.
Adjust the respective tests and add new tests for the /c modifier.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* record.h (enum record_print_flag)
<record_print_indent_calls>: New.
* record.c (get_call_history_modifiers): Recognize /c modifier.
(_initialize_record): Document /c modifier.
* record-btrace.c (btrace_call_history): Add btinfo parameter.
Reorder fields. Optionally indent the function name. Update
all users.
* NEWS: Announce changes.
testsuite/
* gdb.btrace/function_call_history.exp: Fix expected field
order for "record function-call-history".
Add new tests for "record function-call-history /c".
* gdb.btrace/exception.cc: New.
* gdb.btrace/exception.exp: New.
* gdb.btrace/tailcall.exp: New.
* gdb.btrace/x86-tailcall.S: New.
* gdb.btrace/x86-tailcall.c: New.
* gdb.btrace/unknown_functions.c: New.
* gdb.btrace/unknown_functions.exp: New.
* gdb.btrace/Makefile.in (EXECUTABLES): Add new.
doc/
* gdb.texinfo (Process Record and Replay): Document new /c
modifier accepted by "record function-call-history".
Add /i modifier to "record function-call-history" example.
The record instruction-history and record-function-call-history commands start
counting instructions at zero. This is somewhat unintuitive when we start
navigating in the recorded instruction history. Start at one, instead.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* btrace.c (ftrace_new_function): Start counting at one.
* record-btrace.c (record_btrace_info): Adjust number of calls
and insns.
* NEWS: Announce it.
testsuite/
* gdb.btrace/instruction_history.exp: Update.
* gdb.btrace/function_call_history.exp: Update.
The branch trace is represented as 3 vectors:
- a block vector
- a instruction vector
- a function vector
Each vector (except for the first) is computed from the one above.
Change this into a graph where a node represents a sequence of instructions
belonging to the same function and where we have three types of edges to connect
the function segments:
- control flow
- same function (instance)
- call stack
This allows us to navigate in the branch trace. We will need this for "record
goto" and reverse execution.
This patch introduces the data structure and computes the control flow edges.
It also introduces iterator structs to simplify iterating over the branch trace
in control-flow order.
It also fixes PR gdb/15240 since now recursive calls are handled correctly.
Fix the test that got the number of expected fib instances and also the
function numbers wrong.
The current instruction had been part of the branch trace. This will look odd
once we start support for reverse execution. Remove it. We still keep it in
the trace itself to allow extending the branch trace more easily in the future.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* btrace.h (struct btrace_func_link): New.
(enum btrace_function_flag): New.
(struct btrace_inst): Rename to ...
(struct btrace_insn): ...this. Update all users.
(struct btrace_func) <ibegin, iend>: Remove.
(struct btrace_func_link): New.
(struct btrace_func): Rename to ...
(struct btrace_function): ...this. Update all users.
(struct btrace_function) <segment, flow, up, insn, insn_offset)
(number, level, flags>: New.
(struct btrace_insn_iterator): Rename to ...
(struct btrace_insn_history): ...this.
Update all users.
(struct btrace_insn_iterator, btrace_call_iterator): New.
(struct btrace_target_info) <btrace, itrace, ftrace>: Remove.
(struct btrace_target_info) <begin, end, level>
<insn_history, call_history>: New.
(btrace_insn_get, btrace_insn_number, btrace_insn_begin)
(btrace_insn_end, btrace_insn_prev, btrace_insn_next)
(btrace_insn_cmp, btrace_find_insn_by_number, btrace_call_get)
(btrace_call_number, btrace_call_begin, btrace_call_end)
(btrace_call_prev, btrace_call_next, btrace_call_cmp)
(btrace_find_function_by_number, btrace_set_insn_history)
(btrace_set_call_history): New.
* btrace.c (btrace_init_insn_iterator)
(btrace_init_func_iterator, compute_itrace): Remove.
(ftrace_print_function_name, ftrace_print_filename)
(ftrace_skip_file): Change
parameter to const.
(ftrace_init_func): Remove.
(ftrace_debug): Use new btrace_function fields.
(ftrace_function_switched): Also consider gaining and
losing symbol information).
(ftrace_print_insn_addr, ftrace_new_call, ftrace_new_return)
(ftrace_new_switch, ftrace_find_caller, ftrace_new_function)
(ftrace_update_caller, ftrace_fixup_caller, ftrace_new_tailcall):
New.
(ftrace_new_function): Move. Remove debug print.
(ftrace_update_lines, ftrace_update_insns): New.
(ftrace_update_function): Check for call, ret, and jump.
(compute_ftrace): Renamed to ...
(btrace_compute_ftrace): ...this. Rewritten to compute call
stack.
(btrace_fetch, btrace_clear): Updated.
(btrace_insn_get, btrace_insn_number, btrace_insn_begin)
(btrace_insn_end, btrace_insn_prev, btrace_insn_next)
(btrace_insn_cmp, btrace_find_insn_by_number, btrace_call_get)
(btrace_call_number, btrace_call_begin, btrace_call_end)
(btrace_call_prev, btrace_call_next, btrace_call_cmp)
(btrace_find_function_by_number, btrace_set_insn_history)
(btrace_set_call_history): New.
* record-btrace.c (require_btrace): Use new btrace thread
info fields.
(record_btrace_info, btrace_insn_history)
(record_btrace_insn_history, record_btrace_insn_history_range):
Use new btrace thread info fields and new iterator.
(btrace_func_history_src_line): Rename to ...
(btrace_call_history_src_line): ...this. Use new btrace
thread info fields.
(btrace_func_history): Rename to ...
(btrace_call_history): ...this. Use new btrace thread info
fields and new iterator.
(record_btrace_call_history, record_btrace_call_history_range):
Use new btrace thread info fields and new iterator.
testsuite/
* gdb.btrace/function_call_history.exp: Fix expected function
trace.
* gdb.btrace/instruction_history.exp: Initialize traced.
Remove traced_functions.
For testing multi-line test output, gdb.btrace tests used the following
pattern:
gdb_test "..." "
...\r
..."
Change this to:
gdb_test "..." [join [list \
"..." \
"..."] "\r\n"]
Also extract repeated tests into a test function and shorten or remove
test messages.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
testsuite/
* gdb.btrace/function_call_history.exp: Update
* gdb.btrace/instruction_history.exp: Update.
The error message for starting recording twice changed.
Update the expected text to fix resulting regressions.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* gdb.btrace/enable.exp: Update expected text.
Reading symbols from /bin/true...(no debugging symbols found)...done.
(gdb) b _start
Function "_start" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (_start) pending.
(gdb) r
Starting program: /bin/true
Breakpoint 1, 0x00000039a0400af0 in _start () from /lib64/ld-linux-x86-64.so.2
(gdb) rec b
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /bin/true
Breakpoint 1, 0x00000039a0400af0 in _start () from /lib64/ld-linux-x86-64.so.2
(gdb) rec b
gdb/record-btrace.c:154: internal-error: record_btrace_open:
Assertion `record_btrace_thread_observer == NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
gdb/
* record-btrace.c (record_btrace_close): Call
record_btrace_auto_disable.
testsuite/
* gdb.btrace/enable.exp: Add regression test.
Markus Metzger
Joel Brobecker
Markus Metzger