Fix build regression introduced by 0860c437cb ("btrace: Store
btrace_insn in an std::vector"):
src/gdb/btrace.c: In function ‘void ftrace_add_pt(btrace_thread_info*, pt_insn_decoder*, int*, std::vector<unsigned int>&)’:
src/gdb/btrace.c:1329:38: error: invalid initialization of reference of type ‘const btrace_insn&’ from expression of type ‘btrace_insn*’
ftrace_update_insns (bfun, &btinsn);
^
src/gdb/btrace.c:648:1: note: in passing argument 2 of ‘void ftrace_update_insns(btrace_function*, const btrace_insn&)’
ftrace_update_insns (struct btrace_function *bfun, const btrace_insn &insn)
^
gdb/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* btrace.c (ftrace_add_pt): Pass btrace_insn to
ftrace_update_insns by reference instead of pointer.
Because it contains a non-POD type field (flags), the type btrace_insn
should be new'ed/delete'd. Replace the VEC (btrace_insn_s) in
btrace_function with an std::vector.
gdb/ChangeLog:
* btrace.h (btrace_insn_s, DEF_VEC_O (btrace_insn_s)): Remove.
(btrace_function) <insn>: Change type to use std::vector.
* btrace.c (ftrace_debug, ftrace_call_num_insn,
ftrace_find_call, ftrace_new_gap, ftrace_update_function,
ftrace_update_insns, ftrace_compute_global_level_offset,
btrace_stitch_bts, btrace_clear, btrace_insn_get,
btrace_insn_end, btrace_insn_next, btrace_insn_prev): Adjust to
change to std::vector.
(ftrace_update_insns): Adjust to change to std::vector, change
type of INSN parameter.
(btrace_compute_ftrace_bts): Adjust call to ftrace_update_insns.
* record-btrace.c (btrace_call_history_insn_range,
btrace_compute_src_line_range,
record_btrace_frame_prev_register): Adjust to change to
std::vector.
* python/py-record-btrace.c (recpy_bt_func_instructions): Adjust
to change to std::vector.
This removes save_inferior_ptid, a cleanup function, in favor of
scoped_restore.
This also fixes a possible (it seems unlikely that it could happen in
practice) memory leak -- save_inferior_ptid should have used
make_cleanup_dtor, because it allocated memory.
I tested this on the buildbot. However, there are two caveats to
this. First, sometimes it seems I misread the results. Second, I
think this patch touches some platforms that can't be tested by the
buildbot. So, extra care seems warranted.
ChangeLog
2017-08-18 Tom Tromey <tom@tromey.com>
Pedro Alves <palves@redhat.com>
* spu-multiarch.c (parse_spufs_run): Use scoped_restore.
* sol-thread.c (sol_thread_resume, sol_thread_wait)
(sol_thread_xfer_partial, rw_common): Use scoped_restore.
* procfs.c (procfs_do_thread_registers): Use scoped_restore.
* proc-service.c (ps_xfer_memory): Use scoped_restore.
* linux-tdep.c (linux_corefile_thread): Remove a cleanup.
(linux_get_siginfo_data): Add "thread" argument. Use
scoped_restore.
* linux-nat.c (linux_child_follow_fork)
(check_stopped_by_watchpoint): Use scoped_restore.
* infrun.c (displaced_step_prepare_throw, write_memory_ptid)
(THREAD_STOPPED_BY, handle_signal_stop): Use scoped_restore.
(restore_inferior_ptid, save_inferior_ptid): Remove.
* btrace.c (btrace_fetch): Use scoped_restore.
* bsd-uthread.c (bsd_uthread_fetch_registers)
(bsd_uthread_store_registers): Use scoped_restore.
* breakpoint.c (reattach_breakpoints, detach_breakpoints): Use
scoped_restore.
* aix-thread.c (aix_thread_resume, aix_thread_wait)
(aix_thread_xfer_partial): Use scoped_restore.
* inferior.h (save_inferior_ptid): Remove.
Newer versions of libipt support instruction flow decoder events instead of
indicating those events with flags in struct pt_insn. Add support for them in
GDB.
gdb/
* btrace.c (handle_pt_insn_events): New.
(ftrace_add_pt): Call handle_pt_insn_events. Rename ERRCODE into
STATUS. Split into this and ...
(handle_pt_insn_event_flags): ... this.
This used to hold a pair of pointers to the previous and next function segment
that belong to this function call. Replace with a pair of indices into the
vector of function segments.
This used to hold a pair of pointers to the previous and next function segment
in execution flow order. It is no longer necessary as the previous and next
function segments now are simply the previous and next elements in the vector
of function segments.
These are no longer needed and might hold invalid addresses once we change the
vector of function segment pointers into a vector of function segment objects
where a reallocation of the vector changes the address of its elements.
Directly insert new btrace_function pointers into the vector and have the
vector own these pointers. This allows us to later retrieve these objects by
their number directly after creation whereas at the moment we have to wait
until the vector is fully populated.
This requires to pull btrace_thread_info through different functions but
cleans up the code for freeing the trace.
The user would always get the instruction_history and function_call_history
objects of the current thread, not the thread for which the gdb.Record object
was created.
The attached testcase fails without this patch and passes with the patch.
struct btrace_insn is not a POD [1] so we shouldn't be using memset to
initialize it [2].
Use list-initialization instead, wrapped in a "pt insn to btrace insn"
function, which looks like just begging to be added next to the
existing pt_reclassify_insn/pt_btrace_insn_flags functions.
[1] - because its field "flags" is not POD, because enum_flags has a
non-trivial default ctor.
gdb/ChangeLog:
2017-04-25 Pedro Alves <palves@redhat.com>
* btrace.c (pt_btrace_insn_flags): Change parameter type to
reference.
(pt_btrace_insn): New function.
(ftrace_add_pt): Remove memset call and use pt_btrace_insn.
Currently, btrace_find_insn_by_number will iterate over all function call
segments to find the one that contains the needed instruction. This linear
search is too slow for the upcoming Python bindings that will use this
function to access instructions. This patch introduces a vector in struct
btrace_thread_info that holds pointers to all recorded function segments and
allows to use binary search.
The proper solution is to turn the underlying tree into a vector of objects
and use indices for access. This requires more work. A patch set is
currently being worked on and will be published later.
Signed-off-by: Tim Wiederhake <tim.wiederhake@intel.com>
gdb/ChangeLog:
* btrace.c (btrace_fetch): Copy function call segments pointer
into a vector.
(btrace_clear): Clear the vector.
(btrace_find_insn_by_number): Use binary search to find the correct
function call segment.
* btrace.h (brace_fun_p): New typedef.
(struct btrace_thread_info) <functions>: New field.
Change-Id: I8a7f67e80bfe4ff62c4192f74a2153a70bf2a035
Signed-off-by: Tim Wiederhake <tim.wiederhake@intel.com>
gdb/ChangeLog:
* record-btrace.c (btrace_ui_out_decode_error): Move most of it ...
* btrace.c (btrace_decode_error): ... here. New function.
* btrace.h (btrace_decode_error): New export.
Change-Id: I2b4b43a55dbfd9f526a540d2ad52a6708f31feba
This gives all instructions, including gaps, a unique number. Add a function
to retrieve the error code if a btrace instruction iterator points to an
invalid instruction.
Signed-off-by: Tim Wiederhake <tim.wiederhake@intel.com>
gdb/ChangeLog:
* btrace.c (ftrace_call_num_insn, btrace_insn_get_error): New function.
(ftrace_new_function, btrace_insn_number, btrace_insn_cmp,
btrace_find_insn_by_number): Remove special case for gaps.
* btrace.h (btrace_insn_get_error): New export.
(btrace_insn_number, btrace_find_insn_by_number): Adjust comment.
* record-btrace.c (btrace_insn_history): Print number for gaps.
(record_btrace_info, record_btrace_goto): Handle gaps.
Change-Id: I8eb0e48a95f4278522fea74ea13526bfe6898ecc
On 64-bit FC25, the _dl_runtime_resolve function uses a conditional branch to
'call' a particular variant optimized for that system:
(gdb) disas _dl_runtime_resolve_avx_opt
Dump of assembler code for function _dl_runtime_resolve_avx_opt:
0x00007ffff7deeb60 <+0>: push %rax
0x00007ffff7deeb61 <+1>: push %rcx
0x00007ffff7deeb62 <+2>: push %rdx
0x00007ffff7deeb63 <+3>: mov $0x1,%ecx
0x00007ffff7deeb68 <+8>: xgetbv
0x00007ffff7deeb6b <+11>: mov %eax,%r11d
0x00007ffff7deeb6e <+14>: pop %rdx
0x00007ffff7deeb6f <+15>: pop %rcx
0x00007ffff7deeb70 <+16>: pop %rax
0x00007ffff7deeb71 <+17>: and $0x4,%r11d
0x00007ffff7deeb75 <+21>: bnd je 0x7ffff7def4a0 <_dl_runtime_resolve_sse_vex>
End of assembler dump.
When computing the function-level trace, btrace treats this as a switch from
_dl_runtime_resolve_avx_opt to _dl_runtime_resolve_sse_vex. We know that we
switched functions but we can't really say in which caller/callee relationship
those two functions are.
In addition to preserving the indentaion level, also preserve the caller
information. This is a heuristic since we don't really know. But at least in
this case, this seems to be the right thing to do.
This fixes a fail in gdb.btrace/rn-dl-bind.exp on 64-bit FC25.
gdb/
* btrace.c (ftrace_new_switch): Preserve up link and flags.
When recording is started for a running thread, GDB was able to start tracing
but then failed to read registers to insert the initial entry for the current
PC. We don't really need that initial entry if we don't know where exactly we
started recording. Skip that step to allow recording to be started while
threads are running.
If we do run into errors, we need to undo the tracing enable to not leak this
thread. The operation did not complete so our caller won't clean up this
thread.
For the BTRACE_FORMAT_PT btrace format, we don't need that initial entry since
it will be recorded in the trace. We can omit the call to btrace_add_pc.
gdb/
* btrace.c (btrace_enable): Do not call btrace_add_pc for
BTRACE_FORMAT_PT or if can_access_registers_ptid returns false.
(btrace_fetch): Assert can_access_registers_ptid.
* record-btrace.c (require_btrace_thread, record_btrace_info): Call
validate_registers_access.
testsuite/
* gdb.btrace/enable-running.c: New.
* gdb.btrace/enable-running.exp: New.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
Most of the time, the trace should be in one piece. This case is handled fine
by GDB. In some cases, however, there may be gaps in the trace. They result
from trace decode errors or from overflows.
A gap in the trace means we lost an unknown amount of trace. Gaps can be very
small, such as a few instructions in the same function, or they can be rather
big. We may, for example, lose a few function calls or returns. The trace may
continue in a different function and we likely don't know how we got there.
Even though we can't say how the program executed across a gap, higher levels
may not be impacted too much by it. Let's assume we have functions a-e and a
trace that looks roughly like this:
a
\
b b
\ /
c <gap> c
/
d d
\ /
e
Even though we can't say for sure, it is likely that b and c are the same
function instance before and after the gap. This patch is trying to connect
the c and b function segments across the gap.
This will add a to the back trace of b on the right hand side. The changes are
reflected in GDB's internal representation of the trace and will improve:
- the output of "record function-call-history /c"
- the output of "backtrace" in replay mode
- source stepping in replay mode
will be improved indirectly via the improved back trace
I don't have an automated test for this patch; decode errors will be fixed and
overflows occur sporadically and are quite rare. I tested it by hacking GDB to
provoke a decode error and on the expected gap in the gdb.btrace/dlopen.exp
test.
The issue is that we can't predict where we will be able to re-sync in case of
errors. For the expected decode error in gdb.btrace/dlopen.exp, for example, we
may be able to re-sync somewhere in dlclose, in test, in main, or not at all.
Here's one example run of gdb.btrace/dlopen.exp with and without this patch.
(gdb) info record
Active record target: record-btrace
Recording format: Intel Processor Trace.
Buffer size: 16kB.
warning: Non-contiguous trace at instruction 66608 (offset = 0xa83, pc = 0xb7fdcc31).
warning: Non-contiguous trace at instruction 66652 (offset = 0xa9b, pc = 0xb7fdcc31).
warning: Non-contiguous trace at instruction 66770 (offset = 0xacb, pc = 0xb7fdcc31).
warning: Non-contiguous trace at instruction 66966 (offset = 0xb60, pc = 0xb7ff5ee4).
warning: Non-contiguous trace at instruction 66994 (offset = 0xb74, pc = 0xb7ff5f24).
warning: Non-contiguous trace at instruction 67334 (offset = 0xbac, pc = 0xb7ff5e6d).
warning: Non-contiguous trace at instruction 69022 (offset = 0xc04, pc = 0xb7ff60b3).
warning: Non-contiguous trace at instruction 69116 (offset = 0xc1c, pc = 0xb7ff60b3).
warning: Non-contiguous trace at instruction 69504 (offset = 0xc74, pc = 0xb7ff605d).
warning: Non-contiguous trace at instruction 83648 (offset = 0xecc, pc = 0xb7ff6134).
warning: Decode error (-13) at instruction 83876 (offset = 0xf48, pc = 0xb7fd6380): no memory mapped at this address.
warning: Non-contiguous trace at instruction 83876 (offset = 0x11b7, pc = 0xb7ff1c70).
Recorded 83948 instructions in 912 functions (12 gaps) for thread 1 (process 12996).
(gdb) record instruction-history 83876, +2
83876 => 0xb7fec46f <call_init.part.0+95>: call *%eax
[decode error (-13): no memory mapped at this address]
[disabled]
83877 0xb7ff1c70 <_dl_close_worker.part.0+1584>: nop
Without the patch, the trace is disconnected and the backtrace is short:
(gdb) record goto 83876
#0 0xb7fec46f in call_init.part () from /lib/ld-linux.so.2
(gdb) backtrace
#0 0xb7fec46f in call_init.part () from /lib/ld-linux.so.2
#1 0xb7fec5d0 in _dl_init () from /lib/ld-linux.so.2
#2 0xb7ff0fe3 in dl_open_worker () from /lib/ld-linux.so.2
Backtrace stopped: not enough registers or memory available to unwind further
(gdb) record goto 83877
#0 0xb7ff1c70 in _dl_close_worker.part.0 () from /lib/ld-linux.so.2
(gdb) backtrace
#0 0xb7ff1c70 in _dl_close_worker.part.0 () from /lib/ld-linux.so.2
#1 0xb7ff287a in _dl_close () from /lib/ld-linux.so.2
#2 0xb7fc3d5d in dlclose_doit () from /lib/libdl.so.2
#3 0xb7fec354 in _dl_catch_error () from /lib/ld-linux.so.2
#4 0xb7fc43dd in _dlerror_run () from /lib/libdl.so.2
#5 0xb7fc3d98 in dlclose () from /lib/libdl.so.2
#6 0x0804860a in test ()
#7 0x08048628 in main ()
With the patch, GDB is able to connect the trace pieces and we get a full
backtrace.
(gdb) record goto 83876
#0 0xb7fec46f in call_init.part () from /lib/ld-linux.so.2
(gdb) backtrace
#0 0xb7fec46f in call_init.part () from /lib/ld-linux.so.2
#1 0xb7fec5d0 in _dl_init () from /lib/ld-linux.so.2
#2 0xb7ff0fe3 in dl_open_worker () from /lib/ld-linux.so.2
#3 0xb7fec354 in _dl_catch_error () from /lib/ld-linux.so.2
#4 0xb7ff02e2 in _dl_open () from /lib/ld-linux.so.2
#5 0xb7fc3c65 in dlopen_doit () from /lib/libdl.so.2
#6 0xb7fec354 in _dl_catch_error () from /lib/ld-linux.so.2
#7 0xb7fc43dd in _dlerror_run () from /lib/libdl.so.2
#8 0xb7fc3d0e in dlopen@@GLIBC_2.1 () from /lib/libdl.so.2
#9 0xb7ff28ee in _dl_runtime_resolve () from /lib/ld-linux.so.2
#10 0x0804841c in ?? ()
#11 0x08048470 in dlopen@plt ()
#12 0x080485a3 in test ()
#13 0x08048628 in main ()
(gdb) record goto 83877
#0 0xb7ff1c70 in _dl_close_worker.part.0 () from /lib/ld-linux.so.2
(gdb) backtrace
#0 0xb7ff1c70 in _dl_close_worker.part.0 () from /lib/ld-linux.so.2
#1 0xb7ff287a in _dl_close () from /lib/ld-linux.so.2
#2 0xb7fc3d5d in dlclose_doit () from /lib/libdl.so.2
#3 0xb7fec354 in _dl_catch_error () from /lib/ld-linux.so.2
#4 0xb7fc43dd in _dlerror_run () from /lib/libdl.so.2
#5 0xb7fc3d98 in dlclose () from /lib/libdl.so.2
#6 0x0804860a in test ()
#7 0x08048628 in main ()
It worked nicely in this case but it may, of course, also lead to weird
connections; it is a heuristic, after all.
It works best when the gap is small and the trace pieces are long.
gdb/
* btrace.c (bfun_s): New typedef.
(ftrace_update_caller): Print caller in debug dump.
(ftrace_get_caller, ftrace_match_backtrace, ftrace_fixup_level)
(ftrace_compute_global_level_offset, ftrace_connect_bfun)
(ftrace_connect_backtrace, ftrace_bridge_gap, btrace_bridge_gaps): New.
(btrace_compute_ftrace_bts): Pass vector of gaps. Collect gaps.
(btrace_compute_ftrace_pt): Likewise.
(btrace_compute_ftrace): Split into this, ...
(btrace_compute_ftrace_1): ... this, and ...
(btrace_finalize_ftrace): ... this. Call btrace_bridge_gaps.
When encountering a return for which we have not seen a corresponding call, GDB
starts a new back trace from level -1, i.e. from the level of the first function
in the trace.
In the presence of trace gaps, this may cause some rather big jump.
(gdb) record function-call-history /c 192, +8
192 sbrk
193 brk
194 __x86.get_pc_thunk.bx
195 brk
196 __kernel_vsyscall
197 [disabled]
198 __kernel_vsyscall
199 brk
200 sbrk
This doesn't help to make things more clear. Let's remain on the same level
instead.
(gdb) record function-call-history /c 192, +8
192 sbrk
193 brk
194 __x86.get_pc_thunk.bx
195 brk
196 __kernel_vsyscall
197 [disabled]
198 __kernel_vsyscall
199 brk
200 sbrk
In this case it will look like we were able to connect the trace parts across
the disabled gap. We were not. More work is required to achieve this.
In the general case, the function-call history for the two trace parts won't
match. They may be off by a few levels or they may be entirely different. All
this patch does is to preserve the indentation level of the record
function-call-history command.
The disabled gap is caused by a sysenter not returning to the next instruction.
(gdb) record function-call-history /i 196, +1
196 __kernel_vsyscall inst 66515,66519
(gdb) record instruction-history 66515
66515 0xb7fdcbf8 <__kernel_vsyscall+0>: push %ecx
66516 0xb7fdcbf9 <__kernel_vsyscall+1>: push %edx
66517 0xb7fdcbfa <__kernel_vsyscall+2>: push %ebp
66518 0xb7fdcbfb <__kernel_vsyscall+3>: mov %esp,%ebp
66519 0xb7fdcbfd <__kernel_vsyscall+5>: sysenter
[disabled]
66520 0xb7fdcc08 <__kernel_vsyscall+16>: pop %ebp
66521 0xb7fdcc09 <__kernel_vsyscall+17>: pop %edx
66522 0xb7fdcc0a <__kernel_vsyscall+18>: pop %ecx
66523 0xb7fdcc0b <__kernel_vsyscall+19>: ret
66524 0xb7e8e09e <brk+30>: xchg %ecx,%ebx
(gdb) disassemble 0xb7fdcbf8, 0xb7fdcc0c
Dump of assembler code from 0xb7fdcbf8 to 0xb7fdcc0c:
0xb7fdcbf8 <__kernel_vsyscall+0>: push %ecx
0xb7fdcbf9 <__kernel_vsyscall+1>: push %edx
0xb7fdcbfa <__kernel_vsyscall+2>: push %ebp
0xb7fdcbfb <__kernel_vsyscall+3>: mov %esp,%ebp
0xb7fdcbfd <__kernel_vsyscall+5>: sysenter
0xb7fdcbff <__kernel_vsyscall+7>: nop
0xb7fdcc00 <__kernel_vsyscall+8>: nop
0xb7fdcc01 <__kernel_vsyscall+9>: nop
0xb7fdcc02 <__kernel_vsyscall+10>: nop
0xb7fdcc03 <__kernel_vsyscall+11>: nop
0xb7fdcc04 <__kernel_vsyscall+12>: nop
0xb7fdcc05 <__kernel_vsyscall+13>: nop
0xb7fdcc06 <__kernel_vsyscall+14>: int $0x80
0xb7fdcc08 <__kernel_vsyscall+16>: pop %ebp
0xb7fdcc09 <__kernel_vsyscall+17>: pop %edx
0xb7fdcc0a <__kernel_vsyscall+18>: pop %ecx
0xb7fdcc0b <__kernel_vsyscall+19>: ret
End of assembler dump.
I've seen this on 32-bit Fedora 23. I have not investigated what causes this
and whether we can avoid the gap in the first place. Let's first try to make
GDB handle such gaps more gracefully.
gdb/
* btrace.c (ftrace_new_return): Start from the previous function's level
if we can't find a matching call for a return.
An unconditional jump to the start of a function typically indicates a tail
call.
If we can't determine the start of the function at the destination address, we
used to treat it as a tail call, as well. This results in lots of tail calls
for code for which we don't have symbol information.
Restrict the heuristic to only consider jumps as tail calls that switch
functions in the case where we can't determine the start of a function. This
effectively disables tail call detection for code without symbol information.
gdb/
* btrace.c (ftrace_update_function): Update tail call heuristic.
GDB ignores trace gaps from decode errors or overflows at the beginning of the
trace. There isn't really a gap in the trace; the trace just starts a bit
later than expected.
In cases where there is no trace at all or where the trace is smaller than
expected, this may hide the reason for the missing trace.
Allow leading trace gaps. They will be shown as decode warnings and by the
record function-call-history command.
(gdb) info record
Active record target: record-btrace
Recording format: Intel Processor Trace.
Buffer size: 16kB.
warning: Decode error (-6) at instruction 0 (offset = 0x58, pc = 0x0): unexpected packet context.
warning: Decode error (-6) at instruction 0 (offset = 0xb0, pc = 0x0): unexpected packet context.
warning: Decode error (-6) at instruction 0 (offset = 0x168, pc = 0x0): unexpected packet context.
warning: Decode error (-6) at instruction 54205 (offset = 0xe08, pc = 0x0): unexpected packet context.
warning: Decode error (-6) at instruction 54205 (offset = 0xe60, pc = 0x0): unexpected packet context.
warning: Decode error (-6) at instruction 54205 (offset = 0xed8, pc = 0x0): unexpected packet context.
Recorded 91582 instructions in 1111 functions (6 gaps) for thread 1 (process 15710).
(gdb) record function-call-history /c 1
1 [decode error (-6): unexpected packet context]
2 [decode error (-6): unexpected packet context]
3 [decode error (-6): unexpected packet context]
4 _dl_addr
5 ??
6 _dl_addr
7 ??
8 ??
9 ??
10 ??
Leading trace gaps will not be shown by the record instruction-history command
without further changes.
gdb/
* btrace.c (btrace_compute_ftrace_bts, ftrace_add_pt): Allow leading gaps.
* record-btrace.c (record_btrace_single_step_forward)
(record_btrace_single_step_backward): Jump back to last instruction if
step ends at a gap.
(record_btrace_goto_begin): Skip gaps.
Trace gaps due to overflows or non-contiguous trace are ignored in the 'info
record' command. Fix that.
Also add a warning when decoding the trace and print the instruction number
preceding the trace gap in that warning message. It looks like this:
(gdb) info record
Active record target: record-btrace
Recording format: Intel Processor Trace.
Buffer size: 16kB.
warning: Decode error (-13) at instruction 101044 (offset = 0x29f0, pc = 0x7ffff728a642): no memory mapped at this address.
Recorded 101044 instructions in 2093 functions (1 gaps) for thread 1 (process 5360).
(gdb) record instruction-history 101044
101044 0x00007ffff728a640: pop %r13
[decode error (-13): no memory mapped at this address]
Remove the dead code that was supposed to print a gaps warning at the end of
trace decode. This isn't really needed since we now print a warning for each
gap.
gdb/
* btrace.c (ftrace_add_pt): Fix gap indication. Add warning for non-
contiguous trace and overflow. Rephrase trace decode warning and print
instruction number. Remove dead gaps warning.
(btrace_compute_ftrace_bts): Rephrase warnings and print instruction
number.
With libipt's headers installed, a build with --enable-build-with-cxx
fails with:
.../src/gdb/btrace.c: In function ‘btrace_insn_flag pt_btrace_insn_flags(const pt_insn*)’:
.../src/gdb/btrace.c:734:33: error: invalid conversion from ‘int’ to ‘btrace_insn_flag’ [-fpermissive]
enum btrace_insn_flag flags = 0;
^
.../src/gdb/btrace.c:737:11: error: invalid conversion from ‘int’ to ‘btrace_insn_flag’ [-fpermissive]
flags |= BTRACE_INSN_FLAG_SPECULATIVE;
^
gdb/ChangeLog:
2016-04-15 Pedro Alves <palves@redhat.com>
* btrace.c (pt_btrace_insn_flags): Change return type to
btrace_insn_flags. Use btrace_insn_flags for local.
Add a new function to print a thread ID, in the style of paddress,
plongest, etc. and adjust all CLI-reachable paths to use it.
This gives us a single place to tweak to print inferior-qualified
thread IDs later:
- [Switching to thread 1 (Thread 0x7ffff7fc2740 (LWP 8155))]
+ [Switching to thread 1.1 (Thread 0x7ffff7fc2740 (LWP 8155))]
etc., though for now, this has no user-visible change.
No regressions on x86_64 Fedora 20.
gdb/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
* breakpoint.c (remove_threaded_breakpoints)
(print_one_breakpoint_location): Use print_thread_id.
* btrace.c (btrace_enable, btrace_disable, btrace_teardown)
(btrace_fetch, btrace_clear): Use print_thread_id.
* common/print-utils.c (CELLSIZE): Delete.
(get_cell): Rename to ...
(get_print_cell): ... this and made extern. Adjust call callers.
Adjust to use PRINT_CELL_SIZE.
* common/print-utils.h (get_print_cell): Declare.
(PRINT_CELL_SIZE): New.
* gdbthread.h (print_thread_id): Declare.
* infcmd.c (signal_command): Use print_thread_id.
* inferior.c (print_inferior): Use print_thread_id.
* infrun.c (handle_signal_stop)
(insert_exception_resume_breakpoint)
(insert_exception_resume_from_probe)
(print_signal_received_reason): Use print_thread_id.
* record-btrace.c (record_btrace_info)
(record_btrace_resume_thread, record_btrace_cancel_resume)
(record_btrace_step_thread, record_btrace_wait): Use
print_thread_id.
* thread.c (thread_apply_all_command): Use print_thread_id.
(print_thread_id): New function.
(thread_apply_command): Use print_thread_id.
(thread_command, thread_find_command, do_captured_thread_select):
Use print_thread_id.
The GNU Coding Standards say:
"Please do not include any trademark acknowledgements in GNU
software packages or documentation."
gdb/ChangeLog:
2016-01-12 Pedro Alves <palves@redhat.com>
Remove use of the registered trademark symbol throughout.
gdb/gdbserver/ChangeLog:
2016-01-12 Pedro Alves <palves@redhat.com>
Remove use of the registered trademark symbol throughout.
gdb/doc/ChangeLog:
2016-01-12 Pedro Alves <palves@redhat.com>
Remove use of the registered trademark symbol throughout.
In btrace_pt_readmem_callback, we read memory inside TRY/CATCH and return in
case of an error return value. This corrupts the cleanup chain, which
eventually results in a SEGV when doing or discarding cleanups later on.
gdb/
* btrace.c (btrace_pt_readmem_callback): Do not return in TRY/CATCH.
testsuite/
* gdb.btrace/dlopen.exp: New.
* gdb.btrace/dlopen.c: New.
* gdb.btrace/dlopen-dso.c: New.
If GDB has been configured without libipt support, i.e. HAVE_LIBIPT is
undefined, and is running on a system that supports Intel(R) Processor Trace,
GDB will run into an internal error when trying to decode the trace.
(gdb) record btrace
(gdb) s
usage (name=0x7fffffffe954 "fib-64")
at src/fib.c:12
12 fprintf(stderr, "usage: %s <num>\n", name);
(gdb) info record
Active record target: record-btrace
Recording format: Intel(R) Processor Trace.
Buffer size: 16kB.
gdb/btrace.c:971: internal-error: Unexpected branch trace format.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
This requires a system with Linux kernel 4.1 or later running on a 5th
Generation Intel Core processor or later.
The issue is documented as PR 19297.
When trying to enable branch tracing, in addition to checking the target
support for the requested branch tracing format, also check whether GDB
supports. it.
gdb/
* btrace.c (btrace_enable): Check whether HAVE_LIBIPT is defined.
testsuite/
* lib/gdb.exp (skip_btrace_pt_tests): Check for a "GDB does not
support" error.
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.
Fix the ARI warning about the use of unsigned long long. We can't use
ULONGEST as this is defined unsigned long on 64-bit systems. This will
result in a compile error when storing a pointer to an unsigned long long
structure field (declared in perf_event.h as __u64) in a ULONGEST * variable.
Use size_t to hold the buffer size inside GDB and __u64 when interfacing the
Linux kernel.
gdb/
* nat/linux-btrace.c (perf_event_read): Change the type of DATA_HEAD.
(perf_event_read_all): Change the type of SIZE and DATA_HEAD.
(perf_event_read_bts): Change the type of SIZE and READ.
(linux_enable_bts): Change the type of SIZE, PAGES, DATA_SIZE,
and DATA_OFFSET. Move DATA_SIZE declaration. Restrict the buffer size
to UINT_MAX. Check for overflows when using DATA_HEAD from the perf
mmap page.
(linux_enable_pt): Change the type of PAGES and SIZE. Restrict the
buffer size to UINT_MAX.
(linux_read_bts): Change the type of BUFFER_SIZE, SIZE, DATA_HEAD, and
DATA_TAIL.
* nat/linux-btrace.h (struct perf_event_buffer)<size, data_head>
<last_head>: Change type.
* common/btrace-common.h (struct btrace_dat_pt) <size>: Change type.
* common/btrace-common.c (btrace_data_append): Change the type of
SIZE.
* btrace.c (parse_xml_raw): Change the type of SIZE. Change oddness
check.
Add support for dumping new Intel(R) Processor Trace packets in the
"maint btrace packet-history" command.
gdb/
* btrace.c (pt_print_packet): Print stop, vmcs, tma, mtc, cyc, and
mnt packets.
When compiling GDB with 32-bit BFD, the build fails with:
In file included from btrace.h:33:0,
from btrace.c:23:
/usr/include/intel-pt.h:1643:51: note: expected 'int (*)(uint8_t *, size_t,
const struct pt_asid *, uint64_t, void *)' but argument is of type 'int
(*)(gdb_byte *, size_t, const struct pt_asid *, CORE_ADDR, void *)' extern
pt_export int pt_image_set_callback(struct pt_image *image, ^
gdb/
* btrace.c (btrace_pt_readmem_callback): Change type of PC argument.
Add maintenance commands that help debugging the btrace record target.
The following new commands are added:
maint info btrace
Print information about branch tracing internals.
maint btrace packet-history
Print the raw branch tracing data.
maint btrace clear-packet-history
Discard the stored raw branch tracing data.
maint btrace clear
Discard all branch tracing data. It will be fetched and processed
anew by the next "record" command.
maint set|show btrace pt skip-pad
Set and show whether PAD packets are skipped when computing the
packet history.
gdb/
* btrace.c: Include gdbcmd.h, cli/cli-utils.h, and ctype.h.
(maint_btrace_cmdlist, maint_btrace_set_cmdlist)
(maint_btrace_show_cmdlist, maint_btrace_pt_set_cmdlist)
(maint_btrace_pt_show_cmdlist, maint_btrace_pt_skip_pad)
(btrace_maint_clear): New.
(btrace_fetch, btrace_clear): Call btrace_maint_clear.
(pt_print_packet, btrace_maint_decode_pt)
(btrace_maint_update_pt_packets, btrace_maint_update_packets)
(btrace_maint_print_packets, get_uint, get_context_size, no_chunk)
(maint_btrace_packet_history_cmd)
(maint_btrace_clear_packet_history_cmd, maint_btrace_clear_cmd)
(maint_btrace_cmd, maint_btrace_set_cmd, maint_btrace_show_cmd)
(maint_btrace_pt_set_cmd, maint_btrace_pt_show_cmd)
(maint_info_btrace_cmd, _initialize_btrace): New.
* btrace.h (btrace_pt_packet, btrace_pt_packet_s)
(btrace_maint_packet_history, btrace_maint_info): New.
(btrace_thread_info) <maint>: New.
* NEWS: Announce it.
doc/
* gdb.texinfo (Maintenance Commands): Document "maint btrace"
commands.
Store the raw branch trace data that has been read from the target.
This data can be used for maintenance commands as well as for generating
a core file for the "record save" command.
gdb/
* btrace.c (btrace_fetch): Append the new trace data.
(btrace_clear): Clear the stored trace data.
* btrace.h (btrace_thread_info) <data>: New.
* common/btrace-common.h (btrace_data_clear)
(btrace_data_append): New.
* common/btrace-common.c (btrace_data_clear)
(btrace_data_append): 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.
Tom Tromey
John Baldwin
Pedro Alves
Simon Marchi
Markus Metzger
Tim Wiederhake
Joel Brobecker
Simon Marchi