Pedro Alves [Fri, 25 Nov 2022 16:20:22 +0000 (16:20 +0000)]
all-stop "follow-fork parent" and selecting another thread
With:
- catch a fork in thread 1
- select thread 2
- set follow-fork child
- next
... follow_fork notices that thread 1 had last stopped for a fork
which hasn't been followed yet, and because thread 1 is not the
current thread, GDB aborts the execution command, presenting the stop
in thread 1.
That makes sense, as only the forking thread (thread 1) survives in
the child, so better stop and let the user decide how to proceed.
However, with:
- catch a fork in thread 1
- select thread 2
- set follow-fork parent << note difference here
- next
... GDB does the same: follow_fork notices that thread 1 had last
stopped for a fork which hasn't been followed yet, and because thread
1 is not the current thread, GDB aborts the execution command,
presenting the stop in thread 1.
Aborting/stopping in this case doesn't make sense to me. As we're
following the parent, thread 2 will still continue to exist in the
parent. What the child does after we've followed the parent shouldn't
matter -- it can go on running free, be detached, etc., depending on
"set schedule-multiple", "set detach-on-fork", etc. That does not
influence the execution command that the user issued for the parent
thread.
So this patch changes GDB in that direction -- in follow_fork, if
following the parent, and we've switched threads meanwhile, switch
back to the unfollowed thread, follow it (stay with the parent), and
don't abort/stop. If we're following a fork (as opposed to vfork),
then switch back again to the thread that the user was trying to
resume. If following a vfork, however, stay with the vforking-thread
selected, as we will need to see a vfork_done event first, before we
can resume any other thread.
As I was working on this, I managed to end up calling target_resume
for a solo-thread resume (to collect the vfork_done event), with
scope_ptid pointing at the vfork parent thread, and inferior_ptid
pointing to the vfork child. For a solo-thread resume, the scope_ptid
argument to target_resume must the same as inferior_ptid. The mistake
was caught by the assertion in target_resume, like so:
Pedro Alves [Thu, 17 Nov 2022 18:25:36 +0000 (18:25 +0000)]
Make follow_fork not rely on get_last_target_status
Currently, if
- you're in all-stop mode,
- the inferior last stopped because of a fork catchpoint,
when you next resume the program, gdb checks whether it had last
stopped for a fork/vfork, and if so,
a) if the current thread is the one that forked, gdb follows the
parent/child, depending on "set follow-fork" mode.
b) if the current thread is some other thread (because you switched
threads meanwhile), gdb switches back to that thread, gdb follows
the parent/child, and stops the resumption command.
There's a problem in b), however -- if you have "set schedule-multiple
off", which is the default, or "set scheduler-locking on", gdb will
still switch back to the forking thread, even if you didn't want to
resume it. For example, with:
(gdb) catch fork
(gdb) c
* thread 1 stops for fork
(gdb) thread 2
(gdb) set scheduler-locking on
(gdb) c
gdb switches back to thread 1, and follows the fork.
Or with:
(gdb) add-inferior -exec prog
(gdb) inferior 2
(gdb) start
(gdb) inferior 1
(gdb) catch fork
(gdb) c
* thread 1.1 stops for fork
(gdb) inferior 2
(gdb) set schedule-multiple off # this is the default
(gdb) c
gdb switches back to thread 1.1, and follows the fork.
Another issue is that, because follow_fork relies on
get_last_target_status to find the thread that has a pending fork, it
is possible to confuse it. For example, "run" or "start" call
init_wait_for_inferior, which clears the last target status, so this:
(gdb) catch fork
(gdb) c
* thread 1 stops for fork
(gdb) add-inferior -exec prog
(gdb) inferior 2
(gdb) start
(gdb) set follow-fork child
(gdb) inferior 1
(gdb) n
... does not follow to the fork child of inferior 1, because the
get_last_target_status call in follow_fork doesn't return a
TARGET_WAITKIND_FORKED. Thanks to Simon for this example.
All of the above are fixed by this patch. It changes follow_fork to
not look at get_last_target_status, but to instead iterate over the
set of threads that the user is resuming, and find the one that has a
pending_follow kind of fork/vfork.
gdb.base/foll-fork.exp is augmented to exercise the last "start"
scenario described above. The other cases will be exercised in the
testcase added by the following patch.
Pedro Alves [Thu, 17 Nov 2022 23:21:04 +0000 (23:21 +0000)]
Improve "info program"
With gdb.base/catch-follow-exec.exp, we currently see:
~~~~~~~~~~~~~~~
(gdb)
continue
Continuing.
process 693251 is executing new program: /usr/bin/ls
[New inferior 2]
[New process 693251]
[Switching to process 693251]
Thread 2.1 "ls" hit Catchpoint 2 (exec'd /usr/bin/ls), 0x00007ffff7fd0100 in _start () from /lib64/ld-linux-x86-64.so.2
(gdb)
info prog
No selected thread.
~~~~~~~~~~~~~~~
Note the "No selected thread" output. That is totally bogus, because
there _is_ a selected thread. What GDB really means, is that it can't
find the thread that had the latest (user-visible) stop. And that
happens because "info program" gets that info from
get_last_target_status, and the last target status has been cleared.
However, GDB also checks if there is a selected thread, here:
.. the null_ptid part. That is also bogus, because what matters is
the thread that last reported a stop, not the current thread:
- in all-stop mode, "info program" displays info about the last stop.
That may have happened on a thread different from the selected
thread.
- in non-stop mode, because all threads are controlled individually,
"info program" shows info about the last stop of the selected
thread.
The current code already behaves this way, though in a poor way. This
patch reimplements it, such that the all-stop version now finds the
thread that last reported an event via the 'previous_thread' strong
reference. Being a strong reference means that if that thread has
exited since the event was reported, 'previous_thread' will still
point to it, so we can say that the thread exited meanwhile.
The patch also extends "info program" output a little, to let the user
know which thread we are printing info for. For example, for the
gdb.base/catch-follow-exec.exp case we shown above, we now get:
(gdb) info prog
Last stopped for thread 2.1 (process 710867).
Using the running image of child process 710867.
Program stopped at 0x7ffff7fd0100.
It stopped at breakpoint 2.
Type "info stack" or "info registers" for more information.
(gdb)
while in non-stop mode, we get:
(gdb) info prog
Selected thread 2.1 (process 710867).
Using the running image of child process 710867.
Program stopped at 0x7ffff7fd0100.
It stopped at breakpoint 2.
Type "info stack" or "info registers" for more information.
(gdb)
In both cases, the first line of output is new.
The existing code considered these running/exited cases as an error,
but I think that that's incorrect, since this is IMO just plain
execution info as well. So the patch makes those cases regular
prints, not errors.
If the thread is running, we get, in non-stop mode:
(gdb) info prog
Selected thread 2.1 (process 710867).
Selected thread is running.
... and in all-stop:
(gdb) info prog
Last stopped for thread 2.1 (process 710867).
Thread is now running.
If the thread has exited, we get, in non-stop mode:
(gdb) info prog
Selected thread 2.1 (process 710867).
Selected thread has exited.
... and in all-stop:
(gdb) info prog
Last stopped for thread 2.1 (process 710867).
Thread has since exited.
The gdb.base/info-program.exp testcase was much extended to test
all-stop/non-stop and single-threaded/multi-threaded.
Pedro Alves [Thu, 17 Nov 2022 23:08:58 +0000 (23:08 +0000)]
Convert previous_inferior_ptid to strong reference to thread_info
I originally wrote this patch, because while working on some other
patch, I spotted a regression in the
gdb.multi/multi-target-no-resumed.exp.exp testcase. Debugging the
issue, I realized that the problem was related to how I was using
previous_inferior_ptid to look up the thread the user had last
selected. The problem is that previous_inferior_ptid alone doesn't
tell you which target that ptid is from, and I was just always using
the current target, which was incorrect. Two different targets may
have threads with the same ptid.
I decided to fix this by replacing previous_inferior_ptid with a
strong reference to the thread, called previous_thread.
I have since found a new motivation for this change -- I would like to
tweak "info program" to not rely on get_last_target_status returning a
ptid that still exists in the thread list. With both the follow_fork
changes later in this series, and the step-over-thread-exit changes,
that can happen, as we'll delete threads and not clear the last
waitstatus.
A new update_previous_thread function is added that can be used to
update previous_thread from inferior_ptid. This must be called in
several places that really want to get rid of previous_thread thread,
and reset the thread id counter, otherwise we get regressions like
these:
(gdb) info threads -gid
Id GId Target Id Frame
- * 1 1 Thread 2974541.2974541 "tids-gid-reset" main () at src/gdb/testsuite/gdb.multi/tids-gid-reset.c:21
- (gdb) PASS: gdb.multi/tids-gid-reset.exp: single-inferior: after restart: info threads -gid
+ * 1 2 Thread 2958361.2958361 "tids-gid-reset" main () at src/gdb/testsuite/gdb.multi/tids-gid-reset.c:21
+ (gdb) FAIL: gdb.multi/tids-gid-reset.exp: single-inferior: after restart: info threads -gid
and:
Core was generated by `build/gdb/testsuite/outputs/gdb.reverse/sigall-precsave/si'.
Program terminated with signal SIGTRAP, Trace/breakpoint trap.
#0 gen_ABRT () at src/gdb/testsuite/gdb.reverse/sigall-reverse.c:398
398 kill (getpid (), SIGABRT);
+[Current thread is 1 (LWP 2662066)]
Restored records from core file build/gdb/testsuite/outputs/gdb.reverse/sigall-precsave/sigall.precsave.
#0 gen_ABRT () at src/gdb/testsuite/gdb.reverse/sigall-reverse.c:398
398 kill (getpid (), SIGABRT);
continue
Continuing.
-Program received signal SIGABRT, Aborted.
+Thread 1 received signal SIGABRT, Aborted.
0x00007ffff7dfd55b in kill () at ../sysdeps/unix/syscall-template.S:78
78 ../sysdeps/unix/syscall-template.S: No such file or directory.
-(gdb) PASS: gdb.reverse/sigall-precsave.exp: sig-test-1: get signal ABRT
+(gdb) FAIL: gdb.reverse/sigall-precsave.exp: sig-test-1: get signal ABRT
I.e., GDB was failing to restart the thread counter back to 1, because
the previous_thread thread was being help due to the strong reference.
Tested on GNU/Linux native, gdbserver and gdbserver + "maint set
target-non-stop on".
gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
Pedro Alves [Sat, 3 Dec 2022 16:20:51 +0000 (16:20 +0000)]
Tweak "Using the running image of ..." output
Currently, "info files" and "info program" on a few native targets
show:
(gdb) info files
Symbols from "/home/pedro/gdb/tests/threads".
Native process:
Using the running image of child Thread 0x7ffff7d89740 (LWP 1097968).
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
(gdb) info program
Using the running image of child Thread 0x7ffff7d89740 (LWP 1097968).
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Program stopped at 0x555555555278.
...
This patch changes them to:
(gdb) info files
Symbols from "/home/pedro/gdb/tests/threads".
Native process:
Using the running image of child process 1097968.
^^^^^^^^^^^^^^^
...
(gdb) info program
Using the running image of child process 1097968.
^^^^^^^^^^^^^^^
Program stopped at 0x555555555278.
...
... which I think makes a lot more sense in this context. The "info
program" manual entry even says:
"Display information about the status of your program: whether it is
running or not, what process it is, and why it stopped."
^^^^^^^^^^^^^
This change affects ptrace targets, procfs targets, and Windows.
H.J. Lu [Sat, 3 Dec 2022 02:43:20 +0000 (18:43 -0800)]
x86: Allow 16-bit register source for LAR and LSL
Since LAR and LSL only access 16 bits of the source operand, regardless
of operand size, allow 16-bit register source for LAR and LSL, and always
disassemble LAR and LSL with 16-bit source operand.
Simon Marchi [Fri, 25 Nov 2022 21:27:15 +0000 (16:27 -0500)]
gdb/linux-nat: add pid parameter to linux_proc_xfer_memory_partial
Add a pid parameter to linux_proc_xfer_memory_partial, making the
inferior_ptid reference bubble up close to the target_ops::xfer_partial
boundary. No behavior change expected.
Simon Marchi [Mon, 28 Nov 2022 16:43:13 +0000 (11:43 -0500)]
gdb: merge solib-frv aix-solib debug options into "set/show debug solib"
solib implementations are typically used one at a time. So it will be
rare that you will want to enable debug for one solib kind, and
absolutely want to keep the others disabled. To make things simpler,
instead of adding separate variables / macros / commands for each solib
implementation, merge the existing ones (frv and aix) into a unified
"set/show debug solib", with the solib_debug_printf macro.
Jan Beulich [Fri, 2 Dec 2022 08:54:09 +0000 (09:54 +0100)]
x86: drop most OPERAND_TYPE_* (and rework the rest)
With the general use of C99 there's no need anymore to have i386-gen
produce these. For more frequently used ones introduce local #define-s,
while others are simply spelled out directly. While doing this move
some static constants into more narrow scopes.
Note that as a "side effect" this corrects type_names[]'es imm8s entry.
Jan Beulich [Fri, 2 Dec 2022 08:53:33 +0000 (09:53 +0100)]
x86: simplify and slightly correct XCHG vs NOP checking
For one, because of CheckRegSize, there's no need to check the size of
both (register) operands. And then in process_suffix() check opcode
space rather than the (potentially ambiguous) extension opcode.
Jan Beulich [Fri, 2 Dec 2022 08:53:07 +0000 (09:53 +0100)]
x86: also use D for XCHG and TEST
Leverage the C (commutative) attribute to also reduce the number of XCHG
and TEST templates we have. This way the reg <-> r/m (and reg <-> reg for
XCHG) forms can also be folded into a single template each, utilizing D.
Tom de Vries [Fri, 2 Dec 2022 07:56:42 +0000 (08:56 +0100)]
[gdb/testsuite] Prevent timeout in gdb.ada/float-bits.exp
Recent commit 32a5aa26256 ("[gdb/testsuite] Fix gdb.ada/float-bits.exp
for powerpc64le") started using command "maint print architecture", which
produces ~275 lines.
Rewrite the corresponding gdb_test_multiple to read line-by-line, to prevent
timeouts on slower test setups.
Note that this doesn't fix a timeout in the test-case on aarch64 due to:
...
gdbarch_dump: read_core_file_mappings = <0x817438>
(gdb) aarch64_dump_tdep: Lowest pc = 0x0x8000
...
Carl Love [Thu, 1 Dec 2022 19:39:45 +0000 (14:39 -0500)]
PowerPC, fix gdb.reverse/finish-reverse-bkpt.exp and gdb.reverse/next-reverse-bkpt-over-sr.exp
The tests set a break point with the command break *func. This sets a
breakpoint on the first instruction of the function. PowerPC uses
Global Entry Points (GEP) and Local Entry Points (LEP). The first
instruction in the function is the GEP. The GEP sets up register
r2 before reaching the LEP. When the function is called with func() the
function is entered via the LEP and the test fails because GDB does not
see the breakpoint on the GEP. However, if the function is called via a
function pointer, execution begins at the GEP as the test expects.
Currently finish-reverse-bkpt.exp uses source file finish-reverse.c and
next-reverse-bpkt-over-sr.exp uses source file step-reverse.c A new
source file was created for tests finish-reverse-bkpt.exp and
next-reverse-bkpt-over-sr.exp. The new files use the new function
pointer method to call the functions so the tests will work correctly on
both PowerPC with a GEP and LEP as well as on other systems. The GEP is
the same as the LEP on non PowerPC systems.
The expect files were changed to use the new source files and to set the
initial break point for the rest of the test on the function pointer call
for the function.
This patch fixes two PowerPC test failures in each of the tests
gdb.reverse/finish-reverse-bkpt.exp and
gdb.reverse/next-reverse-bkpt-over-sr.exp.
Patch tested on PowerPC and Intel X86-64 with no regressions.
Tom Tromey [Wed, 30 Nov 2022 20:50:27 +0000 (13:50 -0700)]
Remove call to registers_changed from windows-nat.c
I noticed that windows_nat_target::interrupt calls registers_changed.
However, I don't think there's any reason to do this, because this
will happen automatically when the inferior stop is processed.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Tom Tromey [Wed, 30 Nov 2022 15:51:09 +0000 (08:51 -0700)]
Remove the_windows_nat_target global
I belatedly realized that the "the_windows_nat_target" global isn't
really necessary. It's only used in one place, where 'this' would be
simpler and clearer. This patch removes the global entirely.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Tom Tromey [Thu, 3 Nov 2022 19:49:17 +0000 (13:49 -0600)]
Add name canonicalization for C
PR symtab/29105 shows a number of situations where symbol lookup can
result in the expansion of too many CUs.
What happens is that lookup_signed_typename will try to look up a type
like "signed int". In cooked_index_functions::expand_symtabs_matching,
when looping over languages, the C++ case will canonicalize this type
name to be "int" instead. Then this method will proceed to expand
every CU that has an entry for "int" -- i.e., nearly all of them. A
crucial component of this is that the caller, objfile::lookup_symbol,
does not do this canonicalization, so when it tries to find the symbol
for "signed int", it fails -- causing the loop to continue.
This patch fixes the problem by introducing name canonicalization for
C. The idea here is that, by making C and C++ agree on the canonical
name when a symbol name can have multiple spellings, we avoid the bad
behavior in objfile::lookup_symbol (and any other such code -- I don't
know if there is any).
Unlike C++, C only has a few situations where canonicalization is
needed. And, in particular, due to the lack of overloading (thus
avoiding any issues in linespec) and due to the way c-exp.y works, I
think that no canonicalization is needed during symbol lookup -- only
during symtab construction. This explains why lookup_name_info is not
touched.
The stabs reader is modified on a "best effort" basis.
The DWARF reader needed one small tweak in dwarf2_name to avoid a
regression in dw2-unusual-field-names.exp. I think this is adequately
explained by the comment, but basically this is a scenario that should
not occur in real code, only the gdb test suite.
lookup_signed_typename is simplified. It used to search for two
different type names, but now gdb can search just for the canonical
form.
gdb.dwarf2/enum-type.exp needed a small tweak, because the
canonicalizer turns "unsigned integer" into "unsigned int integer".
It seems better here to use the correct C type name.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29105 Tested-by: Simon Marchi <simark@simark.ca> Reviewed-by: Andrew Burgess <aburgess@redhat.com>
Tom Tromey [Fri, 4 Nov 2022 20:08:13 +0000 (14:08 -0600)]
Remove language check from dwarf2_compute_name
dwarf2_compute_name has a redundant check of the CU's language -- this
is also checked in dwarf2_canonicalize_name. Removing this slightly
simplifies a future patch.
Simon Marchi [Thu, 1 Dec 2022 16:44:41 +0000 (11:44 -0500)]
gdb/dwarf: add some QUIT macros
While testing the fix for PR 29105, I noticed I couldn't ctrl-C my way
out of GDB expanding many symtabs. GDB was busy in a loop in
cooked_index_functions::expand_symtabs_matching. Add a QUIT there. I
also happened to see a spot in
cooked_index_functions::expand_matching_symbols where a QUIT would be
useful too, since we iterate over a potentially big number of index
entries and expand CUs in the loop. Add one there too.
Change-Id: Ie1d650381df7f944c16d841b3e592d2dce7306c3 Approved-By: Kevin Buettner <kevinb@redhat.com>
Simon Marchi [Tue, 29 Nov 2022 16:28:58 +0000 (11:28 -0500)]
gdb: remove prune_threads in thread_db_target::update_thread_list
Pedro mentioned that this prune_threads call in
thread_db_target::update_thread_list was not needed, and it was probably
an oversight to leave it there in the work following commit e8032dde10b
("Push pruning old threads down to the target"). That commit changed
the "find new threads" target operation to "update thread list", making
the target responsible of adding new threads and removing exited
threads, rather than just adding new threads. Commit e8032dde10b moved
the prune_threads calls previously done in common code into each
target's update_thread_list method, in order to keep the existing
behavior, which is why this prune_threads call ended up there.
In the mean time, the linux-nat target was taught to update_thread_list,
and thread_db_target::update_thread_list defers to that for any live
inferior, so the prune_threads call is not needed there. Otherwise, the
thread_db_target::update_thread_list implementation based on
td_ta_thr_iter_p only knows how to add new threads, not how to delete
exited threads, but that is only used for non-live inferiors, where
threads can't exit anyway. So the prune_threads call is not needed for
that case either.
Change-Id: I127fd4f84c25086f97853dadf34c5cec6816840d Approved-By: Pedro Alves <pedro@palves.net>
Tom Tromey [Wed, 30 Nov 2022 18:27:10 +0000 (11:27 -0700)]
Avoid timeouts in gdb.compile
PR compile/29541 points out that some of the C++ tests in gdb.compile
will time out when the glibc debuginfo is installed. This was
interfering with my hacking on gdb by making test runs extremely long,
so I looked into it.
Internally the bug seems to be that gdb tries to convert multiple
symbols named "var" via the compiler interface; one such symbol (I
didn't track it down too far) causes the C++ compiler plugin to crash.
Unfortunately, the crash is reported as a timeout, as the gdb side of
the plugin simply hangs. This seems like a bug in the plugin RPC
mechanism and, worse, apparently when I wrote this stuff I didn't
really consider error reporting very much at all, so gdb can't really
detect failures in the first place.
Anyway... this patch works around the timeout by compiling a simple
test that should provoke this bug, and then using "untested" if it
notices a GCC crash.
Tom Tromey [Wed, 30 Nov 2022 17:09:20 +0000 (10:09 -0700)]
Remove obsolete check from skip_compile_feature_tests
skip_compile_feature_tests checks for "Command not supported on this
host", but this error was removed by commit e8d8cce6 ("Import mkdtemp
gnulib module, fix mingw build"). This patch removes the obsolete
test.
Tom Tromey [Wed, 30 Nov 2022 16:32:04 +0000 (09:32 -0700)]
Remove one copy of skip_compile_feature_tests
I noticed that there are two identical copies of
skip_compile_feature_tests in the test suite. This removes one from
gdb.exp, in favor of the one in compile-support.exp.
Clément Chigot [Thu, 1 Dec 2022 08:57:09 +0000 (09:57 +0100)]
binutils: improve holes detection in .debug_loclists.
The previous warnings about holes in .debug_loclists sections don't
take into account the headers of each CU and could include the locviews
if they precede the loclist.
The following warning can be triggered between two CU.
... <previous CU views> ... 0000001d <End of list>
Nick Clifton [Thu, 1 Dec 2022 13:09:26 +0000 (13:09 +0000)]
Fix verilog output when the width is > 1.
PR 25202
bfd * bfd.c (VerilogDataEndianness): New variable.
(verilog_write_record): Use VerilogDataEndianness, if set, to
choose the endianness of the output.
(verilog_write_section): Adjust the address by the data width.
binutils* objcopy.c (copy_object): Set VerilogDataEndianness to the
endianness of the input file.
(copy_main): Verifiy the value set by the --verilog-data-width
option.
* testsuite/binutils-all/objcopy.exp: Add tests of the new behaviour.
* testsuite/binutils-all/verilog-I4.hex: New file.
Jan Beulich [Thu, 1 Dec 2022 09:00:26 +0000 (10:00 +0100)]
x86: rework of match_template()'s suffix checking
(Ab)using i386_opcode_modifier for this has been overkill, as the logic
doesn't really require the full structure. With the removal of
LONG_DOUBLE_MNEM_SUFFIX and No_ldSuf there's no good reason at all
anymore to pull out such a loop invariant: We're dealing a check of a
bit in the loop for a simple comparison. Do the original compares inside
the loop, thus also making it easier to understand what is actually
being checked.
Jan Beulich [Thu, 1 Dec 2022 08:59:39 +0000 (09:59 +0100)]
x86/Intel: drop LONG_DOUBLE_MNEM_SUFFIX
With the removal of its use for FPU insns the suffix is now finally
properly misnamed. Drop its use altogether, replacing it by a separate
boolean instead.
Jan Beulich [Thu, 1 Dec 2022 08:59:11 +0000 (09:59 +0100)]
x86/Intel: restrict use of LONG_DOUBLE_MNEM_SUFFIX
As a comment near the top of match_template() already says: We really
only need this pseudo-suffix for far branch handling. Stop "deriving" it
for floating point insns. (Don't bother renaming the now properly
misnamed LONG_DOUBLE_MNEM_SUFFIX, to e.g. FAR_BRANCH_SUFFIX - it's going
to disappear anyway.)
Tom de Vries [Thu, 1 Dec 2022 06:25:04 +0000 (07:25 +0100)]
[gdb/testsuite] Wait longer for core generation
When I run the gdb testsuite on a powerpc64le-linux system with (slow) nfs
file system, I run into timeouts due to core generation, like for instance:
...
(gdb) gcore $outputs/gdb.ada/task_switch_in_core/crash.gcore^M
FAIL: gdb.ada/task_switch_in_core.exp: save a corefile (timeout)
...
Fix this by using with_timeout_factor 3 in gdb_gcore_cmd.
Tested on powerpc64le-linux. Approved-By: Tom Tromey <tom@tromey.com>
The problem is that we're using a hex string for the 128-bit IEEE quad long
double format, but the actual long double float format is:
...
gdbarch_dump: long_double_format = floatformat_ibm_long_double_little^M
...
Fix this by using the hex string obtained by compiling test.c:
...
long double a = 5.0e+25L;
...
like so:
...
$ gcc -mlittle test.c -c -g
...
and running gdb:
...
$ gdb -q -batch test.o -ex "p /x a"
$1 = 0xc1e1c000000000004544adf4b7320335
...
and likewise for -mbig:
...
$ gdb -q -batch test.o -ex "p /x a"
$1 = 0x4544adf4b7320335c1e1c00000000000
...
Tested on powerpc64le-linux.
I excercised the case of floatformat_ibm_long_double_big by
using "set endian big" in the test-case.
Note that for this patch to work correctly, recent commit aaa79cd62b8 ("[gdb]
Improve printing of float formats") is required.
PR testsuite/29816
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29816 Approved-By: Tom Tromey <tom@tromey.com>
Tom de Vries [Wed, 30 Nov 2022 18:29:52 +0000 (19:29 +0100)]
[gdb/testsuite] Fix DUPLICATEs in s390-multiarch.exp
On s390x-linux, I run into:
...
DUPLICATE: gdb.arch/s390-multiarch.exp: Linux v2
DUPLICATE: gdb.arch/s390-multiarch.exp: Linux v2
DUPLICATE: gdb.arch/s390-multiarch.exp: Linux v2
...
Tom de Vries [Wed, 30 Nov 2022 17:49:16 +0000 (18:49 +0100)]
[gdb/testsuite] Enable gdb.arch/s390-disassembler-options.exp for --enable-targets=all
On s390x-linux, I run into:
...
DUPLICATE: gdb.arch/s390-disassembler-options.exp: \
show disassembler-options esa
...
First, reproduce this on x86_64-linux with --enable-targets=all, by replacing
the test for 'istarget "s390*-*-*"' with a test for 'get_set_option_choices
"set architecture" "s390"'.
Fix the DUPLICATE by using with_test_prefix.
Also modernize the test-case by using clean_restart instead of gdb_exit/gdb_start.
Michael Matz [Wed, 16 Nov 2022 15:28:01 +0000 (16:28 +0100)]
section-select: Fix exclude-file-3
this testcase wasn't correctly testing everything, it passed, even
though sections from an excluded file were included. Fixing this
reveals a problem in the new section selector. This fixes that as
well.
Michael Matz [Tue, 22 Nov 2022 14:24:43 +0000 (15:24 +0100)]
section-select: Remove unused code
walk_wild_file, hence walk_wild_section and walk_wild_section_handler
aren't called with the prefix tree. Hence initialization of the latter
and all potential special cases for it aren't used anymore. That also
removes the need to handler_data[] and some associated helper functions.
So, remove all of that.
Michael Matz [Wed, 14 Sep 2022 15:10:27 +0000 (17:10 +0200)]
section-select: Implement a prefix-tree
Now that we have a list of potentially matching sections per wild
statement we can actually pre-fill that one by going once over all input
sections and match their names against a prefix-tree that points to the
potentially matching wild statements.
So instead of looking at all sections names for each glob for each wild
statement we now look at the sections only once and then only check
against those globs that have a possibility of a match at all (usually
only one or two).
This pushes the whole section selection off the profiles.
Michael Matz [Thu, 27 Oct 2022 12:50:40 +0000 (14:50 +0200)]
section-select: Completely rebuild matches
The check_relocs callback (and others) might have created new
section behind our back and some of them (e.g. on powerpc the
"linker stubs" .got) need to come in front of all others, despite
being created late (a symptom would be "TOC opt*" failing on powerpc).
This resets all section matches before updating for newly created
sections (i.e. completely rebuilds the matches).
Michael Matz [Thu, 28 Jul 2022 12:55:05 +0000 (14:55 +0200)]
section-select: Lazily resolve section matches
and remember the results. Before this the order of section matching
is basically:
foreach script-wild-stmt S
foreach pattern P of S
foreach inputfile I
foreach section S of I
match S against P
if match: do action for S
And this process is done three or four times: for each top-level call to
walk_wild() or wild(), that is: check_input_sections, lang_gc_sections,
lang_find_relro_sections and of course map_input_to_output_sections.
So we iterate over all sections of all files many many times (for each
glob). Reality is a bit more complicated (some special glob types don't
need the full iteration over all sections, only over all files), but
that's the gist of it.
For future work this shuffles the whole ordering a bit by lazily doing
the matching process and memoizing results, trading a little memory for
a 75% speedup of the overall section selection process.
This lazy resolution introduces a problem with sections added late
that's corrected in the next patch.
Tom Tromey [Wed, 16 Nov 2022 20:58:06 +0000 (13:58 -0700)]
Bounds check access to Ada task state names
While looking into Ada tasking a little, I noticed that no bounds
checking is done on accesses to the Ada task state names arrays. This
isn't a problem currently, but if the runtime ever added numbers -- or
if there was some kind of runtime corruption -- it could cause a gdb
crash.
This patch adds range checking. It also adds a missing _() call when
printing from the 'task_states' array.
Tom Tromey [Mon, 28 Nov 2022 21:01:35 +0000 (14:01 -0700)]
Rename fields of cli_interp_base::saved_output_files
This renames the fields of cli_interp_base::saved_output_files, as
requested by Simon. I tried to choose names that more obviously
reflect what the field is used for. I also added a couple of
comments.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Tom de Vries [Wed, 30 Nov 2022 10:37:11 +0000 (11:37 +0100)]
[gdb] Improve printing of float formats
Currently, on x86_64, a little endian target, I get:
...
$ gdb -q -batch -ex "maint print architecture" | grep " = floatformat"
gdbarch_dump: bfloat16_format = floatformat_bfloat16_big
gdbarch_dump: double_format = floatformat_ieee_double_big
gdbarch_dump: float_format = floatformat_ieee_single_big
gdbarch_dump: half_format = floatformat_ieee_half_big
gdbarch_dump: long_double_format = floatformat_i387_ext
...
which suggests big endian.
This is due to this bit of code in pformat:
...
/* Just print out one of them - this is only for diagnostics. */
return format[0]->name;
...
Fix this by using gdbarch_byte_order to pick the appropriate index, such that
we have the more accurate:
...
gdbarch_dump: bfloat16_format = floatformat_bfloat16_little
gdbarch_dump: half_format = floatformat_ieee_half_little
gdbarch_dump: float_format = floatformat_ieee_single_little
gdbarch_dump: double_format = floatformat_ieee_double_little
gdbarch_dump: long_double_format = floatformat_i387_ext
...
Jan Beulich [Wed, 30 Nov 2022 08:10:17 +0000 (09:10 +0100)]
x86/Intel: adjustment to restricted suffix derivation
In "x86/Intel: restrict suffix derivation" I think I screwed up
slightly, bringing a piece of code out of sync with its comment, and
resulting in a suffix potentially being derived when one isn't needed.
Jan Beulich [Wed, 30 Nov 2022 08:06:59 +0000 (09:06 +0100)]
x86: clean up after removal of support for gcc <= 2.8.1
At the very least a comment in process_operands() is stale. Beyond that
there are effectively two options:
1) It is possible that FADDP and FMULP were mistakenly not marked as
being in need of dealing with the compiler anomaly, and hence the
respective templates weren't removed at the time when they should
have been.
2) It is also possible that there are indeed uses known beyond compiler
generated output for these two commutative opcodes, and hence the
templates need to stay.
To be on the safe side assume 2: Update the comment and fold the
templates into their "normal" ones (utilizing D), adjusting consuming
code accordingly.
For FMULP also add a comment paralleling a similar one FADDP has.
Jan Beulich [Wed, 30 Nov 2022 08:06:33 +0000 (09:06 +0100)]
x86: drop FloatR
There are just 4 templates using it, which can be easily identified by
other means, as D is set only on a very limited number of FPU templates.
Also move the respective conditional out of the code path taken by all
"reverse match" insns (it probably should have been this way already
before, to avoid the one conditional in the common case).
With this the templates which had FloatR dropped no longer differ from
their AT&T syntax + mnemonic counterparts - the only difference is now
which of the two would be recognized. For this, however, we don't need
two templates - we can simply arrange the condition for setting
Opcode_FloatR accordingly.
Jan Beulich [Wed, 30 Nov 2022 08:05:57 +0000 (09:05 +0100)]
x86: extend FPU test coverage for AT&T / Intel mnemonic differences
Before touching the templates, let's ensure we actually cover things:
For one FSUB{,R} and FDIV{,R} would better be tested with operands in
both possible orders. And then -mmnemonic=intel wasn't tested at all.
Joel Brobecker [Sun, 27 Nov 2022 12:43:42 +0000 (16:43 +0400)]
src-release.sh: Fix gdb source tarball build failure due to libsframe
This script was recently changed as follow:
| commit e619dddb3a45780ae66d762756882a3b896b617d
| Date: Tue Nov 15 15:07:13 2022 -0800
| Subject: src-release.sh: Add libsframe
|
| Add libsframe to the list of top level directories that will be included
| in a release.
Since then, the gdb source tarball has been failing with the error
below during the "make configure-host configure-target" phase:
| make[3]: *** No rule to make target '../libsframe/libsframe.la',
| needed by 'libbfd.la'. Stop.
| make[3]: Leaving directory '/tmp/gdb-public/bfd'
This patch fixes the issue by adding libsframe to the list of
GDB_SUPPORT_DIRS, similar to what was done for BINUTILS.
Tom de Vries [Tue, 29 Nov 2022 21:47:31 +0000 (22:47 +0100)]
[gdb/testsuite] Fix gdb.base/vla-optimized-out.exp for ppc64le
On powerpc64le-linux, I run into:
...
(gdb) PASS: gdb.base/vla-optimized-out.exp: o1: printed optimized out vla
p sizeof (a)^M
$2 = <optimized out>^M
(gdb) FAIL: gdb.base/vla-optimized-out.exp: o1: \
printed size of optimized out vla
...
The problem happens as follows.
In order to find the size of the optimized out vla, gdb needs to evaluate:
...
<155> DW_AT_upper_bound : 13 byte block: f3 1 53 23 1 8 20 24 8 20 26 31 1c \
(DW_OP_GNU_entry_value: (DW_OP_reg3 (r3)); DW_OP_plus_uconst: 1;
DW_OP_const1u: 32; DW_OP_shl; DW_OP_const1u: 32; DW_OP_shra; DW_OP_lit1;
DW_OP_minus)
...
When trying to evaluate DW_OP_GNU_entry_value, it looks for a call site
matching the pc, but doesn't find it:
...
$ gdb -q -batch outputs/gdb.base/vla-optimized-out/vla-optimized-out-o1 \
-ex "break f1" -ex run -ex "set debug entry-values 1" -ex "print sizeof (a)"
Breakpoint 1 at 0x1000067c: file vla-optimized-out.c, line 34.
Breakpoint 1, f1 (i=5) at vla-optimized-out.c:34
34 }
DW_OP_entry_value resolving cannot find DW_TAG_call_site 0x100006b0 in main
$1 = <optimized out>
....
The call site lookup fails because the call site label .LVL4:
...
bl f1 # 11 *call_value_nonlocal_aixdi [length = 8]
nop
.LVL4:
...
is not placed directly after the bl insn. This is gcc PR target/107909.
However, after manually fixing the .s file we have instead:
...
Cannot find matching parameter at DW_TAG_call_site 0x10000690 at main
$1 = <optimized out>
...
due to the fact that the call site has no call site parameters.
The call site does have a reference to the corresponding function f1, with
parameter i, for which we find location list entries:
...
0037 1000067c10000680 (DW_OP_reg3 (r3))
004a 1000068010000690 (DW_OP_GNU_entry_value: (DW_OP_reg3 (r3));
DW_OP_stack_value)
...
and we could use the fact that the current pc is in the 1000067c-10000680
range, and that that the range starts at the start of the function, to deduce
that DW_OP_GNU_entry_value: (DW_OP_reg3 (r3)) == DW_OP_reg3 (r3).
But that's a non-trivial enhancement, filed as enhancement PR symtab/29836.
Fix this by allowing <optimized out> for target powerpc and the gcc compiler.
Reviewed-By: Carl Love <cel@us.ibm.com> Tested-By: Carl Love <cel@us.ibm.com>
PR testsuite/29813
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29813
gdb_unload crashed GDB, leaving no trace in the test results. Change it
to use gdb_test_multiple, so that it leaves an UNRESOLVED result. I
think it is good practice anyway.
Make it return the result of gdb_test_multiple directly, change
gdb.python/py-objfile.exp accordingly.
Change gdb.base/endian.exp as well to avoid duplicate test names.
Change gdb.base/gnu-debugdata.exp to avoid recording a test result,
since gdb_unload does it already now.
Change-Id: I59a1e4947691330797e6ce23277942547c437a48 Approved-By: Tom de Vries <tdevries@suse.de>
... the testsuite only outputs PASSes, and an ERROR, resulting from an
uncaught exception. This is a bit sneaky, because ERRORs are not
reported in the test summary. In certain circumstances, it can be easy
to miss.
Normally, gdb_test_multiple outputs an UNRESOLVED when GDB crashes. But
this is only if it manages to send the command, and it's that command
that crashes GDB. Here, the ERROR is due to the fact that GDB had
already crashed by the time we entered gdb_test_multiple and tried to
send a command. GDB was crashed by the previous "file" command, sent by
gdb_unload. Because gdb_unload uses bare expect, it didn't record a
test failure when crashing GDB (this will be addressed separately).
In this patch, I propose to make gdb_test_multiple call unresolved
directly and return -1 send_gdb fails. This way, if GDB is already
crashed by the time we enter gdb_test_multiple, it will leave a trace in
the test results in the form of an UNRESOLVED. It will also spare us
the not-so-useful-in-my-opinion TCL backtrace.
Before, it looks like:
ERROR: Couldn't send python print(objfile.filename) to GDB.
ERROR: : spawn id exp9 not open
while executing
"expect {
-i exp9 -timeout 10
-re ".*A problem internal to GDB has been detected" {
fail "$message (GDB internal error)"
gdb_internal_error..."
("uplevel" body line 1)
invoked from within
"uplevel $body" NONE : spawn id exp9 not open
And after:
Couldn't send python print(objfile.filename) to GDB.
UNRESOLVED: gdb.python/py-objfile.exp: objfile.filename after objfile is unloaded
Change-Id: I72af8dc0d687826fc3f76911c27a9e5f91b677ba Approved-By: Tom de Vries <tdevries@suse.de>
Max Filippov [Wed, 3 May 2017 20:13:52 +0000 (13:13 -0700)]
xtensa: allow dynamic configuration
Import include/xtensa-dynconfig.h that defines XCHAL_* macros as fields
of a structure returned from the xtensa_get_config_v<x> function call.
Define that structure and fill it with default parameter values
specified in the include/xtensa-config.h.
Define reusable function xtensa_load_config that tries to load
configuration and return an address of an exported object from it.
Define functions xtensa_get_config_v{1,2} that use xtensa_load_config
to get structures xtensa_config_v{1,2}, either dynamically configured
or the default.
bfd/
* Makefile.am (BFD32_BACKENDS, BFD32_BACKENDS_CFILES): Append
xtensa-dynconfig.c.
* Makefile.in: Regenerate.
* configure: Regenerate.
* configure.ac (xtensa_elf32_be_vec, xtensa_elf32_le_vec): Add
xtensa-dynconfig.lo to the tb.
* elf32-xtensa.c (xtensa-config.h): Replace #include with
xtensa-dynconfig.h.
(XSHAL_ABI, XTHAL_ABI_WINDOWED, XTHAL_ABI_CALL0): Remove
definitions.
* xtensa-dynconfig.c: New file.
* xtensa-isa.c (xtensa-dynconfig.h): New #include.
(xtensa_get_modules): New function.
(xtensa_isa_init): Call xtensa_get_modules instead of taking
address of global xtensa_modules.
gas/
* config/tc-xtensa.c (xtensa-config.h): Replace #include with
xtensa-dynconfig.h.
(XTHAL_ABI_WINDOWED, XTHAL_ABI_CALL0, XTENSA_MARCH_EARLIEST):
Remove definitions.
* config/tc-xtensa.h (xtensa-config.h): Replace #include with
xtensa-dynconfig.h.
* config/xtensa-relax.c (xtensa-config.h): Replace #include with
xtensa-dynconfig.h.
(XCHAL_HAVE_WIDE_BRANCHES): Remove definition.
Andrew Burgess [Mon, 14 Nov 2022 14:45:05 +0000 (14:45 +0000)]
gdb/testsuite: remove use of then keyword from library files
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the testsuite
library files (in boards/, config/, and lib/). Previous commits have
removed all uses of the 'then' keyword from the test script files,
this commit just cleans up the library files.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 14:31:52 +0000 (14:31 +0000)]
gdb/testsuite: remove use of then keyword from gdb.*/*.exp scripts
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the remaining
gdb.*/*.exp scripts. Previous commits have done the bulk of this
removal, this commit just handles the remaining directories that each
contain a low number of instances.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 14:28:22 +0000 (14:28 +0000)]
gdb/testsuite: remove use of then keyword from gdb.multi/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.multi/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 14:24:37 +0000 (14:24 +0000)]
gdb/testsuite: remove use of then keyword from gdb.fortran/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.fortran/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 14:22:46 +0000 (14:22 +0000)]
gdb/testsuite: remove use of then keyword from gdb.disasm/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.disasm/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 14:20:53 +0000 (14:20 +0000)]
gdb/testsuite: remove use of then keyword from gdb.reverse/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.reverse/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 14:18:33 +0000 (14:18 +0000)]
gdb/testsuite: remove use of then keyword from gdb.trace/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.trace/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 14:15:49 +0000 (14:15 +0000)]
gdb/testsuite: remove use of then keyword from gdb.threads/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.threads/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 14:12:07 +0000 (14:12 +0000)]
gdb/testsuite: remove use of then keyword from gdb.python/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.python/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 14:06:11 +0000 (14:06 +0000)]
gdb/testsuite: remove use of then keyword from gdb.cp/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.cp/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 11:39:14 +0000 (11:39 +0000)]
gdb/testsuite: remove use of then keyword from gdb.arch/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.arch/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 11:31:04 +0000 (11:31 +0000)]
gdb/testsuite: remove use of then keyword from gdb.base/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.base/
test script directory.
There should be no changes in what is tested after this commit.
Andrew Burgess [Mon, 14 Nov 2022 10:55:35 +0000 (10:55 +0000)]
gdb/testsuite: remove use of then keyword from gdb.ada/*.exp
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.ada/
test script directory.
There should be no changes in what is tested after this commit.
Tom Tromey [Thu, 17 Nov 2022 17:24:38 +0000 (10:24 -0700)]
Don't let gdb_stdlog use pager
When using the "set logging" commands, cli_interp_base::set_logging
will send gdb_stdlog output (among others) to the tee it makes for
gdb_stdout. However, this has the side effect of also causing logging
to use the pager. This is PR gdb/29787.
This patch fixes the problem by keeping stderr and stdlog separate
from stdout, preserving the rule that only gdb_stdout should page.
Tom Tromey [Thu, 17 Nov 2022 16:09:59 +0000 (09:09 -0700)]
Don't let tee_file own a stream
Right now, tee_file owns the second stream it writes to. This is done
for the convenience of the users. In a subsequent patch, this will no
longer be convenient, so this patch moves the responsibility for
ownership to the users of tee_file.
Tom Tromey [Thu, 17 Nov 2022 15:16:44 +0000 (08:16 -0700)]
Remove 'saved_output' global
CLI redirect uses a global variable, 'saved_output'. However, globals
are generally bad, and there is no need for this one -- it can be a
member of cli_interp_base. This patch makes this change.
Hannes Domani [Mon, 28 Nov 2022 18:32:43 +0000 (19:32 +0100)]
Don't use auto for lambda parameter
Older gcc versions (here 4.9.2) can't handle auto for a lambda parameter:
../../gdb/windows-nat.c: In member function 'void windows_nat_target::delete_thread(ptid_t, DWORD, bool)':
../../gdb/windows-nat.c:629:12: error: use of 'auto' in lambda parameter declaration only available with -std=c++1y or -std=gnu++1y [-Werror]
[=] (auto &th)
^
Andrew Burgess [Thu, 27 Oct 2022 14:20:10 +0000 (15:20 +0100)]
gdb: mark disassembler function callback types as noexcept
In disasm.h we define a set of types that are used by the various
disassembler classes to hold callback functions before passing the
callbacks into libopcodes.
Because libopcodes is C code, and on some (many?) targets, C code is
compiled without exception support, it is important that GDB not try
to throw an exception over libopcode code.
In the previous commit all the existing callbacks were marked as
noexcept, however, this doesn't protect us from a future change to GDB
either adding a new callback that is not noexcept, or removing the
noexcept keyword from an existing callback.
In this commit I mark all the callback types as noexcept. This means
that GDB's disassembler classes will no longer compile if we try to
pass a callback that is not marked as noexcept.
At least, that's the idea. Unfortunately, it's not that easy.
Before C++17, the noexcept keyword on a function typedef would be
ignored, thus:
using func_type = void (*) (void) noexcept;
void
a_func ()
{
throw 123;
}
void
some_func (func_type f)
{
f ();
}
int
main ()
{
some_func (a_func);
return 0;
}
Will compile just fine for C++11 and C++14 with GCC. Clang on the
other hand complains that 'noexcept' should not appear on function
types, but then does appear to correctly complain that passing a_func
is a mismatch in the set of exceptions that could be thrown.
Switching to C++17 and both GCC and Clang correctly point out that
passing a_func is an invalid conversion relating to the noexcept
keyword. Changing a_func to:
void
a_func () noexcept
{ /* Nothing. */ }
And for C++17 both GCC and Clang compile this just fine.
My conclusion then is that adding the noexcept keyword to the function
types is pointless while GDB is not compiled as C++17, and silencing
the warnings would require us to jump through a bunch of hoops.
And so, in this commit, I define a macro LIBOPCODE_CALLBACK_NOEXCEPT,
this macro expands to noexcept when compiling for C++17, but otherwise
expands to nothing. I then add this macro to the function types.
I've compiled GDB as the default C++11 and also forced the compile to
C++17. When compiling as C++17 I spotted a few additional places
where callbacks needed to be marked noexcept (these fixes were merged
into the previous commit, but this confirmed to be that the macro is
working as expected).
The reason this is important is the on some hosts, libopcodes, being C
code, will not be compiled with support for handling exceptions. As
such, an attempt to throw an exception over libopcodes code will cause
GDB to terminate.
See bug gdb/29712 for an example of when this happened.
In this commit all the functions that are passed to the disassembler,
and which might be used as callbacks by libopcodes are marked
noexcept.
Ideally, I would have liked to change these typedefs:
using read_memory_ftype = decltype (disassemble_info::read_memory_func);
using memory_error_ftype = decltype (disassemble_info::memory_error_func);
using print_address_ftype = decltype (disassemble_info::print_address_func);
using fprintf_ftype = decltype (disassemble_info::fprintf_func);
using fprintf_styled_ftype = decltype (disassemble_info::fprintf_styled_func);
which are declared in disasm.h, as including the noexcept keyword.
However, when I tried this, I ran into this warning/error:
In file included from ../../src/gdb/disasm.c:25:
../../src/gdb/disasm.h: In constructor ‘gdb_printing_disassembler::gdb_printing_disassembler(gdbarch*, ui_file*, gdb_disassemble_info::read_memory_ftype, gdb_disassemble_info::memory_error_ftype, gdb_disassemble_info::print_address_ftype)’:
../../src/gdb/disasm.h:116:3: error: mangled name for ‘gdb_printing_disassembler::gdb_printing_disassembler(gdbarch*, ui_file*, gdb_disassemble_info::read_memory_ftype, gdb_disassemble_info::memory_error_ftype, gdb_disassemble_info::print_address_ftype)’ will change in C++17 because the exception specification is part of a function type [-Werror=noexcept-type]
116 | gdb_printing_disassembler (struct gdbarch *gdbarch,
| ^~~~~~~~~~~~~~~~~~~~~~~~~
So I've left that change out. This does mean that if somebody adds a
new use of the disassembler classes in the future, and forgets to mark
the callbacks as noexcept, this will compile fine. We'll just have to
manually check for that during review.
Andrew Burgess [Fri, 21 Oct 2022 15:20:58 +0000 (16:20 +0100)]
gdb/python: avoid throwing an exception over libopcodes code
Bug gdb/29712 identifies a problem with the Python disassembler API.
In some cases GDB will try to throw an exception through the
libopcodes disassembler code, however, not all targets include
exception unwind information when compiling C code, for targets that
don't include this information GDB will terminate when trying to pass
the exception through libopcodes.
To explain what GDB is trying to do, consider the following trivial
use of the Python disassembler API:
class ExampleDisassembler(gdb.disassembler.Disassembler):
class MyInfo(gdb.disassembler.DisassembleInfo):
def __init__(self, info):
super().__init__(info)
def __call__(self, info):
info = self.MyInfo(info)
return gdb.disassembler.builtin_disassemble(info)
This disassembler doesn't add any value, it defers back to GDB to do
all the actual work, but it serves to allow us to discuss the problem.
The problem occurs when a Python exception is raised by the
MyInfo.read_memory method. The MyInfo.read_memory method is called
from the C++ function gdbpy_disassembler::read_memory_func. The C++
stack at the point this function is called looks like this:
#0 gdbpy_disassembler::read_memory_func (memaddr=4198805, buff=0x7fff9ab9d2a8 "\220ӹ\232\377\177", len=1, info=0x7fff9ab9d558) at ../../src/gdb/python/py-disasm.c:510
#1 0x000000000104ba06 in fetch_data (info=0x7fff9ab9d558, addr=0x7fff9ab9d2a9 "ӹ\232\377\177") at ../../src/opcodes/i386-dis.c:305
#2 0x000000000104badb in ckprefix (ins=0x7fff9ab9d100) at ../../src/opcodes/i386-dis.c:8571
#3 0x000000000104e28e in print_insn (pc=4198805, info=0x7fff9ab9d558, intel_syntax=-1) at ../../src/opcodes/i386-dis.c:9548
#4 0x000000000104f4d4 in print_insn_i386 (pc=4198805, info=0x7fff9ab9d558) at ../../src/opcodes/i386-dis.c:9949
#5 0x00000000004fa7ea in default_print_insn (memaddr=4198805, info=0x7fff9ab9d558) at ../../src/gdb/arch-utils.c:1033
#6 0x000000000094fe5e in i386_print_insn (pc=4198805, info=0x7fff9ab9d558) at ../../src/gdb/i386-tdep.c:4072
#7 0x0000000000503d49 in gdbarch_print_insn (gdbarch=0x5335560, vma=4198805, info=0x7fff9ab9d558) at ../../src/gdb/gdbarch.c:3351
#8 0x0000000000bcc8c6 in disasmpy_builtin_disassemble (self=0x7f2ab07f54d0, args=0x7f2ab0789790, kw=0x0) at ../../src/gdb/python/py-disasm.c:324
### ... snip lots of frames as we pass through Python itself ...
#22 0x0000000000bcd860 in gdbpy_print_insn (gdbarch=0x5335560, memaddr=0x401195, info=0x7fff9ab9e3c8) at ../../src/gdb/python/py-disasm.c:783
#23 0x00000000008995a5 in ext_lang_print_insn (gdbarch=0x5335560, address=0x401195, info=0x7fff9ab9e3c8) at ../../src/gdb/extension.c:939
#24 0x0000000000741aaa in gdb_print_insn_1 (gdbarch=0x5335560, vma=0x401195, info=0x7fff9ab9e3c8) at ../../src/gdb/disasm.c:1078
#25 0x0000000000741bab in gdb_disassembler::print_insn (this=0x7fff9ab9e3c0, memaddr=0x401195, branch_delay_insns=0x0) at ../../src/gdb/disasm.c:1101
So gdbpy_disassembler::read_memory_func is called from the libopcodes
disassembler to read memory, this C++ function then calls into user
supplied Python code to do the work.
If the user supplied Python code raises an gdb.MemoryError exception
indicating the memory read failed, this is fine. The C++ code
converts this exception back into a return value that libopcodes can
understand, and returns to libopcodes.
However, if the user supplied Python code raises some other exception,
what we want is for this exception to propagate through GDB and appear
as if raised by the call to gdb.disassembler.builtin_disassemble. To
achieve this, when gdbpy_disassembler::read_memory_func spots an
unknown Python exception, we must pass the information about this
exception from frame #0 to frame #8 in the above backtrace. Frame #8
is the C++ implementation of gdb.disassembler.builtin_disassemble, and
so it is this function that we want to re-raise the unknown Python
exception, so the user can, if they want, catch the exception in their
code.
The previous mechanism by which the exception was passed was to pack
the details of the Python exception into a C++ exception, then throw
the exception from frame #0, and catch the exception in frame #8,
unpack the details of the Python exception, and re-raise it.
However, this relies on the exception passing through frames #1 to #7,
some of which are in libopcodes, which is C code, and so, might not be
compiled with exception support.
This commit proposes an alternative solution that does not rely on
throwing a C++ exception.
When we spot an unhandled Python exception in frame #0, we will store
the details of this exception within the gdbpy_disassembler object
currently in use. Then we return to libopcodes a value indicating
that the memory_read failed.
libopcodes will now continue to disassemble as though that memory read
failed (with one special case described below), then, when we
eventually return to disasmpy_builtin_disassemble we check to see if
there is an exception stored in the gdbpy_disassembler object. If
there is then this exception can immediately be installed, and then we
return back to Python, when the user will be able to catch the
exception.
There is one extra change in gdbpy_disassembler::read_memory_func.
After the first call that results in an exception being stored on the
gdbpy_disassembler object, any future calls to the ::read_memory_func
function will immediately return as if the read failed. This avoids
any additional calls into user supplied Python code.
My thinking here is that should the first call fail with some unknown
error, GDB should not keep trying with any additional calls. This
maintains the illusion that the exception raised from
MyInfo.read_memory is immediately raised by
gdb.disassembler.builtin_disassemble. I have no tests for this change
though - to trigger this issue would rely on a libopcodes disassembler
that will try to read further memory even after the first failed
read. I'm not aware of any such disassembler that currently does
this, but that doesn't mean such a disassembler couldn't exist in the
future.
With this change in place the gdb.python/py-disasm.exp test should now
pass on AArch64.
Tom Tromey [Sun, 20 Nov 2022 22:08:06 +0000 (15:08 -0700)]
Remove reset_ecs and execution_control_state::reset
I noticed that execution_control_state has a 'reset' method, and
there's also a 'reset_ecs' function that calls it. This patch cleans
this area up a little by adding a parameter to the constructor and (a
change Simon suggested) removing the reset method. Some extraneous
variables are also removed, like:
Andrew Burgess [Tue, 22 Nov 2022 12:45:56 +0000 (12:45 +0000)]
gdb: relax requirement for the map_failed stap probe to be present
From glibc 2.35 and later, the "map_failed" stap probe is no longer
included in glibc. The removal of the probe looks like an accident,
but it was caused by a glibc commit which meant that the "map_failed"
probe could no longer be reached; the compiler then helpfully
optimised out the probe.
In GDB, in solib-svr4.c, we have a list of probes that we look for
related to the shared library loading detection. If any of these
probes are missing then GDB will fall back to the non-probe based
mechanism for detecting shared library loading. The "map_failed"
probe is include in the list of required probes.
This means that on glibc 2.35 (or later) systems, GDB is going to
always fall back to the non-probes based mechanism for detecting
shared library loading.
But, whatever the ultimate decision from the glibc team, given there
are version of glibc in the wild without the "map_failed" probe, we
probably should update GDB to handle this situation.
The "map_failed" probe is already a little strange, very early
versions of glibc didn't include this probe, so, in some cases, if
this probe is missing GDB is happy to ignore it. This is fine, the
action associated with this probe inside GDB is DO_NOTHING, this means
the probe isn't actually required in order for GDB to correctly detect
the loading of shared libraries.
In this commit I propose changing the rules so that any probe whose
action is DO_NOTHING, is optional.
There is one possible downside to this change, and that concerns 'set
stop-on-solib-events on'. If a probe is removed from glibc, but the
old style breakpoint based mechanism is still in place within glibc
for that same event, then GDB will stop when using the old style
non-probe based mechanism, but not when using the probes based
mechanism.
For the map_failed case this is not a problem, both the map_failed
probe, and the call to the old style breakpoint location were
optimised out, and so neither event (probes based, or breakpoint
based) will trigger. This would only become an issue if glibc removed
a probe, but left the breakpoint in place (this would almost certainly
be a bug in glibc).
For now, I'm proposing that we just don't worry about this. Because
some probes have actions that are not DO_NOTHING, then we know the
user will always seem _some_ stops when a shared library is
loaded/unloaded, and (I'm guessing), in most cases, that's all they
care about. I figure when someone complains then we can figure out
what the right solution is then.
With this commit in place, then, when using a glibc 2.35 or later
system, GDB will once again use the stap probes for shared library
detection.
Tom de Vries [Mon, 28 Nov 2022 17:07:12 +0000 (18:07 +0100)]
[gdb/testsuite] Require hw watchpoint in gdb.ada/task_watch.exp
On powerpc64le-linux I run into:
...
(gdb) PASS: gdb.ada/task_watch.exp: info tasks before inserting breakpoint
watch -location value task 3^M
Watchpoint 2: -location value^M
(gdb) PASS: gdb.ada/task_watch.exp: watch -location value task 3
continue^M
Continuing.^M
[Thread 0x7ffff7ccf170 (LWP 65550) exited]^M
[Thread 0x7ffff7abf170 (LWP 65551) exited]^M
FAIL: gdb.ada/task_watch.exp: continue to watchpoint (timeout)
...
On x86_64-linux (where the test-case passes), a hardware watchpoint is used:
...
(gdb) PASS: gdb.ada/task_watch.exp: info tasks before inserting breakpoint
watch -location value task 3^M
Hardware watchpoint 2: -location value^M
...
and after forcing "set can-use-hw-watchpoints 0" we can intermittently
reproduce the same failure.
In the gdb documentation related to watchpoints in multi-threaded programs, we
read:
...
Warning: In multi-threaded programs, software watchpoints have only limited
usefulness. If GDB creates a software watchpoint, it can only watch the value
of an expression in a single thread. If you are confident that the expression
can only change due to the current thread’s activity (and if you are also
confident that no other thread can become current), then you can use software
watchpoints as usual. However, GDB may not notice when a non-current thread’s
activity changes the expression. (Hardware watchpoints, in contrast, watch an
expression in all threads.)
...
Since the ada task construct is mapped onto threads, it seems that the
same limitation holds for tasks.
Fix this by using skip_hw_watchpoint_tests.
Tested on powerpc64-linux. Tested-By: Carl Love <cel@us.ibm.com>
Tom de Vries [Mon, 28 Nov 2022 16:18:47 +0000 (17:18 +0100)]
[gdb/testsuite] Fix gdb.ada/out_of_line_in_inlined.exp for ppc64le
On powerpc64le-linux, with test-case gdb.ada/out_of_line_in_inlined.exp I run
into:
...
(gdb) run ^M
Starting program: foo_o224_021-all ^M
^M
Breakpoint 1, 0x0000000010002f48 in foo_o224_021.child1.child2 (s=...) at \
foo_o224_021.adb:24^M
24 function Child2 (S : String) return Boolean is -- STOP^M
(gdb) FAIL: gdb.ada/out_of_line_in_inlined.exp: scenario=all: \
run to foo_o224_021.child1.child2
...
The breakpoint is correctly set at the local entry point, and given that the
local entry point doesn't correspond to a line number entry, the instruction
address of the breakpoint is shown.
The problem is that test-case doesn't expect the breakpoint address.
Fix this by allowing the breakpoint address to occur.
Michael Matz [Thu, 10 Nov 2022 15:06:20 +0000 (16:06 +0100)]
Only use wild_sort_fast
there's no reason why the tree-based variant can't always be used
when sorting is required, it merely needs to also support filename
sorting and have a fast path for insertion at end (aka rightmost tree
leaf).
The filename sorting isn't tested anywhere and the only scripttempl
that uses it is avr (for 'SORT(*)(.ctors)'), and I believe even there it
was a mistake. Either way, this adds a testcase for filename sorting as
well.
Then the non-BST based sorting can be simplified to only support
the fast case of no sorting required at all (at the same time renaming
the two variants to _sort and _nosort).
Michael Matz [Tue, 22 Nov 2022 14:24:14 +0000 (15:24 +0100)]
Special case more simple patterns
fnmatch is slow, so avoiding it in more cases is good. This implements
a more generic version of match_simple_wild which needs some
pre-processing of patterns. In particular it supports patterns of the
form PREFIX*SUFFIX (where all parts are optional), i.e. a super set of
what's handled now. Most section matchers of this form and hence don't
need any calls to fnmatch anymore.
We retain the implementation of match_simple_wild for the filename
matchers (they aren't called often enough to matter).
Simon Marchi [Fri, 18 Nov 2022 16:06:47 +0000 (11:06 -0500)]
gdb/testsuite: fail if gdb_start_cmd fails
I broke gdb.ada/start.exp, and did not notice it, because it outputs an
UNTESTED if gdb_start_cmd fails. I don't really see when start would
fail and it's not a problem that should be looked at. Change all spots
that call untested after a gdb_start_cmd failure, use fail instead.
Doing so caused some failures with the native-gdbserver board. Some
tests that use "start" were relying on the fact that start would fail
with that board to just return with "untested". Change them to add an
early return if use_gdb_stub returns true.
Some gdb.pascal tests also failed with native-gdbserver, because they
did use gdb_start_cmd to start the inferior, for no good reason.
Convert them to use runto_main instead, which does the right thing if
the target is a stub.
A further refactoring could be to make gdb_start_cmd match the expected
breakpoint hit and the prompt, which it doesn't do currently (it leaves
that to the callers, but not all of them do).
Change-Id: I097370851213e798ff29fb6cf8ba25ef7d2be007 Reviewed-By: Bruno Larsen <blarsen@redhat.com> Approved-By: Andrew Burgess <aburgess@redhat.com>
Tom Tromey [Thu, 20 Oct 2022 13:08:48 +0000 (07:08 -0600)]
Fix range type signed-ness heuristic
The code to create a range type has a heuristic to decide whether the
range is unsigned. However, this heuristic can fail if the upper
bound of the range has its high bit set, because the test is done
using LONGEST.
With this patch, if the underlying type of a range is unsigned, then
the range will always be unsigned. A new test is included.
Regression tested on x86-64 Fedora 34. We've also been using this
internally at AdaCore for a while.
#0 internal_error_loc (file=0x5606b344e740 "/home/smarchi/src/binutils-gdb/gdb/target.c", line=2590, fmt=0x5606b344d6a0 "%s: Assertion `%s' failed.") at /home/smarchi/src/binutils-gdb/gdbsupport/errors.cc:54
#1 0x00005606b6296475 in target_wait (ptid=..., status=0x7fffb9390630, options=...) at /home/smarchi/src/binutils-gdb/gdb/target.c:2590
#2 0x00005606b5767a98 in startup_inferior (proc_target=0x5606bfccb2a0 <the_amd64_linux_nat_target>, pid=3884857, ntraps=1, last_waitstatus=0x0, last_ptid=0x0) at /home/smarchi/src/binutils-gdb/gdb/nat/fork-inferior.c:482
#3 0x00005606b4e6c9c5 in gdb_startup_inferior (pid=3884857, num_traps=1) at /home/smarchi/src/binutils-gdb/gdb/fork-child.c:132
#4 0x00005606b50f14a5 in inf_ptrace_target::create_inferior (this=0x5606bfccb2a0 <the_amd64_linux_nat_target>, exec_file=0x604000039f50 "/home/smarchi/build/binutils-gdb/gdb/test", allargs="", env=0x61500000a580, from_tty=1)
at /home/smarchi/src/binutils-gdb/gdb/inf-ptrace.c:105
#5 0x00005606b53b6d23 in linux_nat_target::create_inferior (this=0x5606bfccb2a0 <the_amd64_linux_nat_target>, exec_file=0x604000039f50 "/home/smarchi/build/binutils-gdb/gdb/test", allargs="", env=0x61500000a580, from_tty=1)
at /home/smarchi/src/binutils-gdb/gdb/linux-nat.c:978
#6 0x00005606b512b79b in run_command_1 (args=0x0, from_tty=1, run_how=RUN_NORMAL) at /home/smarchi/src/binutils-gdb/gdb/infcmd.c:468
#7 0x00005606b512c236 in run_command (args=0x0, from_tty=1) at /home/smarchi/src/binutils-gdb/gdb/infcmd.c:526
When running the kill command, commit_resumed_state for the
process_stratum_target (linux-nat, here) is true. After the kill, when
there are no more threads, commit_resumed_state is still true, as
nothing touches this flag during the kill operation. During the
subsequent run command, run_command_1 does:
We would think that this would clear the commit_resumed_state flag of
our native target, but that's not the case, because
scoped_disable_commit_resumed iterates on non-exited inferiors in order
to find active process targets. And after the kill, the inferior is
exited, and the native target was unpushed from it anyway. So
scoped_disable_commit_resumed doesn't touch the commit_resumed_state
flag of the native target, it stays true. When reaching target_wait, in
startup_inferior (to consume the initial expect stop events while the
inferior is starting up and working its way through the shell),
commit_resumed_state is true, breaking the contract saying that
commit_resumed_state is always false when calling the targets' wait
method.
(note: to be correct, I think that startup_inferior should toggle
commit_resumed between the target_wait and target_resume calls, but I'll
ignore that for now)
I can see multiple ways to fix this. In the end, we need
commit_resumed_state to be cleared by the time we get to that
target_wait. It could be done at the end of the kill command, or at the
beginning of the run command.
To keep things in a coherent state, I'd like to make it so that after
the kill command, when the target is left with no threads, its
commit_resumed_state flag is left to false. This way, we can keep
working with the assumption that a target with no threads (and therefore
no running threads) has commit_resumed_state == false.
Do this by adding a scoped_disable_commit_resumed in target_kill. It
clears the target's commit_resumed_state on entry, and leaves it false
if the target does not have any resumed thread on exit. That means,
even if the target has another inferior with stopped threads,
commit_resumed_state will be left to false, which makes sense.
Add a test that tries to cover various combinations of actions done
while an inferior is running (and therefore while commit_resumed_state
is true on the process target).
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28275
Change-Id: I8e6fe6dc1f475055921520e58cab68024039a1e9 Approved-By: Andrew Burgess <aburgess@redhat.com>
Simon Marchi [Mon, 21 Nov 2022 17:12:12 +0000 (12:12 -0500)]
gdbserver: switch to right process in find_one_thread
New in this version: add a dedicated test.
When I do this:
$ ./gdb -nx --data-directory=data-directory -q \
/bin/sleep \
-ex "maint set target-non-stop on" \
-ex "tar ext :1234" \
-ex "set remote exec-file /bin/sleep" \
-ex "run 1231 &" \
-ex add-inferior \
-ex "inferior 2"
Reading symbols from /bin/sleep...
(No debugging symbols found in /bin/sleep)
Remote debugging using :1234
Starting program: /bin/sleep 1231
Reading /lib64/ld-linux-x86-64.so.2 from remote target...
warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
Reading /lib64/ld-linux-x86-64.so.2 from remote target...
Reading /usr/lib/debug/.build-id/a6/7a1408f18db3576757eea210d07ba3fc560dff.debug from remote target...
[New inferior 2]
Added inferior 2 on connection 1 (extended-remote :1234)
[Switching to inferior 2 [<null>] (<noexec>)]
(gdb) Reading /lib/x86_64-linux-gnu/libc.so.6 from remote target...
attach 3659848
Attaching to process 3659848
/home/smarchi/src/binutils-gdb/gdb/thread.c:85: internal-error: inferior_thread: Assertion `current_thread_ != nullptr' failed.
Note the "attach" command just above. When doing it on the command-line
with a -ex switch, the bug doesn't trigger.
The internal error of GDB is actually caused by GDBserver crashing, and
the error recovery of GDB is not on point. This patch aims to fix just
the GDBserver crash, not the GDB problem.
GDBserver crashes with a segfault here:
(gdb) bt
#0 0x00005555557fb3f4 in find_one_thread (ptid=...) at /home/smarchi/src/binutils-gdb/gdbserver/thread-db.cc:177
#1 0x00005555557fd5cf in thread_db_thread_handle (ptid=<error reading variable: Cannot access memory at address 0xffffffffffffffa0>, handle=0x7fffffffc400, handle_len=0x7fffffffc3f0)
at /home/smarchi/src/binutils-gdb/gdbserver/thread-db.cc:461
#2 0x000055555578a0b6 in linux_process_target::thread_handle (this=0x5555558a64c0 <the_x86_target>, ptid=<error reading variable: Cannot access memory at address 0xffffffffffffffa0>, handle=0x7fffffffc400,
handle_len=0x7fffffffc3f0) at /home/smarchi/src/binutils-gdb/gdbserver/linux-low.cc:6905
#3 0x00005555556dfcc6 in handle_qxfer_threads_worker (thread=0x60b000000510, buffer=0x7fffffffc8a0) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:1645
#4 0x00005555556e00e6 in operator() (__closure=0x7fffffffc5e0, thread=0x60b000000510) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:1696
#5 0x00005555556f54be in for_each_thread<handle_qxfer_threads_proper(buffer*)::<lambda(thread_info*)> >(struct {...}) (func=...) at /home/smarchi/src/binutils-gdb/gdbserver/gdbthread.h:159
#6 0x00005555556e0242 in handle_qxfer_threads_proper (buffer=0x7fffffffc8a0) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:1694
#7 0x00005555556e04ba in handle_qxfer_threads (annex=0x629000000213 "", readbuf=0x621000019100 '\276' <repeats 200 times>..., writebuf=0x0, offset=0, len=4097)
at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:1732
#8 0x00005555556e1989 in handle_qxfer (own_buf=0x629000000200 "qXfer:threads", packet_len=26, new_packet_len_p=0x7fffffffd630) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:2045
#9 0x00005555556e720a in handle_query (own_buf=0x629000000200 "qXfer:threads", packet_len=26, new_packet_len_p=0x7fffffffd630) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:2685
#10 0x00005555556f1a01 in process_serial_event () at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:4176
#11 0x00005555556f4457 in handle_serial_event (err=0, client_data=0x0) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:4514
#12 0x0000555555820f56 in handle_file_event (file_ptr=0x607000000250, ready_mask=1) at /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:573
#13 0x0000555555821895 in gdb_wait_for_event (block=1) at /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:694
#14 0x000055555581f533 in gdb_do_one_event (mstimeout=-1) at /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:264
#15 0x00005555556ec9fb in start_event_loop () at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:3512
#16 0x00005555556f0769 in captured_main (argc=4, argv=0x7fffffffe0d8) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:3992
#17 0x00005555556f0e3f in main (argc=4, argv=0x7fffffffe0d8) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:4078
The reason is a wrong current process when find_one_thread is called.
The current process is the 2nd one, which was just attached. It does
not yet have thread_db data (proc->priv->thread_db is nullptr). As we
iterate on all threads of all process to fulfull the qxfer:threads:read
request, we get to a thread of process 1 for which we haven't read
thread_db information yet (lwp_info::thread_known is false), so we get
into find_one_thread. find_one_thread uses
`current_process ()->priv->thread_db`, assuming the current process
matches the ptid passed as a parameter, which is wrong. A segfault
happens when trying to dereference that thread_db pointer.
Fix this by making find_one_thread not assume what the current process /
current thread is. If it needs to call into libthread_db, which we know
will try to read memory from the current process, then temporarily set
the current process.
In the case where the thread is already know and we return early, we
don't need to switch process.
Add a test to reproduce this specific situation.
Change-Id: I09b00883e8b73b7e5f89d0f47cb4e9c0f3d6caaa Approved-By: Andrew Burgess <aburgess@redhat.com>
projects / thirdparty / binutils-gdb.git / log
