| Age | Commit message (Collapse) | Author | Files | Lines |
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While reviewing the Linux and FreeBSD core dumping code within GDB for
another patch series, I noticed that the code that collects the
registers for each thread and writes these into ELF note format is
basically identical between Linux and FreeBSD.
This commit merges this code and moves it into a new file gcore-elf.c.
The function find_signalled_thread is moved from linux-tdep.c to
gcore.c despite not being shared. A later commit will make use of
this function.
I did merge, and then revert a previous version of this patch (commit
82a1fd3a4935 for the original patch and 03642b7189bc for the revert).
The problem with the original patch is that it introduced a
unconditional dependency between GDB and some ELF specific functions
in the BFD library, e.g. elfcore_write_prstatus and
elfcore_write_register_note. It was pointed out in this mailing list
post:
https://sourceware.org/pipermail/gdb-patches/2021-February/175750.html
that this change was breaking any build of GDB for non-ELF targets.
To confirm this breakage, and to test this new version of GDB I
configured and built for the target x86_64-apple-darwin20.3.0.
Where the previous version of this patch placed all of the common code
into gcore.c, which is included in all builds of GDB, this new patch
only places non-ELF specific generic code (i.e. find_signalled_thread)
into gcore.c, the ELF specific code is put into the new gcore-elf.c
file, which is only included in GDB if BFD has ELF support.
The contents of gcore-elf.c are referenced unconditionally from
linux-tdep.c and fbsd-tdep.c, this is fine, we previously always
assumed that these two targets required ELF support, and we continue
to make that assumption after this patch; nothing has changed there.
With my previous version of this patch the darwin target mentioned
above failed to build, but with the new version, the target builds
fine.
There are a couple of minor changes to the FreeBSD target after this
commit, but I believe that these are changes for the better:
(1) For FreeBSD we always used to record the thread-id in the core
file by using ptid_t.lwp (). In contrast the Linux code did this:
/* For remote targets the LWP may not be available, so use the TID. */
long lwp = ptid.lwp ();
if (lwp == 0)
lwp = ptid.tid ();
Both target now do this:
/* The LWP is often not available for bare metal target, in which case
use the tid instead. */
if (ptid.lwp_p ())
lwp = ptid.lwp ();
else
lwp = ptid.tid ();
Which is equivalent for Linux, but is a change for FreeBSD. I think
that all this means is that in some cases where GDB might have
previously recorded a thread-id of 0 for each thread, we might now get
something more useful.
(2) When collecting the registers for Linux we collected into a zero
initialised buffer. By contrast on FreeBSD the buffer is left
uninitialised. In the new code the buffer is always zero initialised.
I suspect once the registers are copied into the buffer there's
probably no gaps left so this makes no difference, but if it does then
using zeros rather than random bits of GDB's memory is probably a good
thing.
Otherwise, there should be no other user visible changes after this
commit.
Tested this on x86-64/GNU-Linux and x86-64/FreeBSD-12.2 with no
regressions.
gdb/ChangeLog:
* Makefile.in (SFILES): Add gcore-elf.c.
(HFILES_NO_SRCDIR): Add gcore-elf.h
* configure: Regenerate.
* configure.ac: Add gcore-elf.o to CONFIG_OBS if we have ELF
support.
* fbsd-tdep.c: Add 'gcore-elf.h' include.
(struct fbsd_collect_regset_section_cb_data): Delete.
(fbsd_collect_regset_section_cb): Delete.
(fbsd_collect_thread_registers): Delete.
(struct fbsd_corefile_thread_data): Delete.
(fbsd_corefile_thread): Delete.
(fbsd_make_corefile_notes): Call
gcore_elf_build_thread_register_notes instead of the now deleted
FreeBSD code.
* gcore-elf.c: New file, the content was moved here from
linux-tdep.c, functions were renamed and given minor cleanup.
* gcore-elf.h: New file.
* gcore.c (gcore_find_signalled_thread): Moved here from
linux-tdep.c and given a new name. Minor cleanups.
* gcore.h (gcore_find_signalled_thread): Declare.
* linux-tdep.c: Add 'gcore.h' and 'gcore-elf.h' includes.
(struct linux_collect_regset_section_cb_data): Delete.
(linux_collect_regset_section_cb): Delete.
(linux_collect_thread_registers): Delete.
(linux_corefile_thread): Call
gcore_elf_build_thread_register_notes.
(find_signalled_thread): Delete.
(linux_make_corefile_notes): Call gcore_find_signalled_thread.
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gdb/27147)
PR 27147 shows that on sparc64, GDB is unable to properly unwind:
Expected result (from GDB 9.2):
#0 0x0000000000108de4 in puts ()
#1 0x0000000000100950 in hello () at gdb-test.c:4
#2 0x0000000000100968 in main () at gdb-test.c:8
Actual result (from GDB latest git):
#0 0x0000000000108de4 in puts ()
#1 0x0000000000100950 in hello () at gdb-test.c:4
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
The first failing commit is 5b6d1e4fa4fc ("Multi-target support"). The cause
of the change in behavior is due to (thanks for Andrew Burgess for finding
this):
- inferior_ptid is no longer set on entry of target_ops::wait, whereas
it was set to something valid previously
- deep down in linux_nat_target::wait (see stack trace below), we fetch
the registers of the event thread
- on sparc64, fetching registers involves reading memory (in
sparc_supply_rwindow, see stack trace below)
- reading memory (target_ops::xfer_partial) relies on inferior_ptid
being set to the thread from which we want to read memory
This is where things go wrong:
#0 linux_nat_target::xfer_partial (this=0x10000fa2c40 <the_sparc64_linux_nat_target>, object=TARGET_OBJECT_MEMORY, annex=0x0, readbuf=0x7feffe3b000 "", writebuf=0x0, offset=8791798050744, len=8, xfered_len=0x7feffe3ae88) at /home/simark/src/binutils-gdb/gdb/linux-nat.c:3697
#1 0x00000100007f5b10 in raw_memory_xfer_partial (ops=0x10000fa2c40 <the_sparc64_linux_nat_target>, readbuf=0x7feffe3b000 "", writebuf=0x0, memaddr=8791798050744, len=8, xfered_len=0x7feffe3ae88) at /home/simark/src/binutils-gdb/gdb/target.c:912
#2 0x00000100007f60e8 in memory_xfer_partial_1 (ops=0x10000fa2c40 <the_sparc64_linux_nat_target>, object=TARGET_OBJECT_MEMORY, readbuf=0x7feffe3b000 "", writebuf=0x0, memaddr=8791798050744, len=8, xfered_len=0x7feffe3ae88) at /home/simark/src/binutils-gdb/gdb/target.c:1043
#3 0x00000100007f61b4 in memory_xfer_partial (ops=0x10000fa2c40 <the_sparc64_linux_nat_target>, object=TARGET_OBJECT_MEMORY, readbuf=0x7feffe3b000 "", writebuf=0x0, memaddr=8791798050744, len=8, xfered_len=0x7feffe3ae88) at /home/simark/src/binutils-gdb/gdb/target.c:1072
#4 0x00000100007f6538 in target_xfer_partial (ops=0x10000fa2c40 <the_sparc64_linux_nat_target>, object=TARGET_OBJECT_MEMORY, annex=0x0, readbuf=0x7feffe3b000 "", writebuf=0x0, offset=8791798050744, len=8, xfered_len=0x7feffe3ae88) at /home/simark/src/binutils-gdb/gdb/target.c:1129
#5 0x00000100007f7094 in target_read_partial (ops=0x10000fa2c40 <the_sparc64_linux_nat_target>, object=TARGET_OBJECT_MEMORY, annex=0x0, buf=0x7feffe3b000 "", offset=8791798050744, len=8, xfered_len=0x7feffe3ae88) at /home/simark/src/binutils-gdb/gdb/target.c:1375
#6 0x00000100007f721c in target_read (ops=0x10000fa2c40 <the_sparc64_linux_nat_target>, object=TARGET_OBJECT_MEMORY, annex=0x0, buf=0x7feffe3b000 "", offset=8791798050744, len=8) at /home/simark/src/binutils-gdb/gdb/target.c:1415
#7 0x00000100007f69d4 in target_read_memory (memaddr=8791798050744, myaddr=0x7feffe3b000 "", len=8) at /home/simark/src/binutils-gdb/gdb/target.c:1218
#8 0x0000010000758520 in sparc_supply_rwindow (regcache=0x10000fea4f0, sp=8791798050736, regnum=-1) at /home/simark/src/binutils-gdb/gdb/sparc-tdep.c:1960
#9 0x000001000076208c in sparc64_supply_gregset (gregmap=0x10000be3190 <sparc64_linux_ptrace_gregmap>, regcache=0x10000fea4f0, regnum=-1, gregs=0x7feffe3b230) at /home/simark/src/binutils-gdb/gdb/sparc64-tdep.c:1974
#10 0x0000010000751b64 in sparc_fetch_inferior_registers (regcache=0x10000fea4f0, regnum=80) at /home/simark/src/binutils-gdb/gdb/sparc-nat.c:170
#11 0x0000010000759d68 in sparc64_linux_nat_target::fetch_registers (this=0x10000fa2c40 <the_sparc64_linux_nat_target>, regcache=0x10000fea4f0, regnum=80) at /home/simark/src/binutils-gdb/gdb/sparc64-linux-nat.c:38
#12 0x00000100008146ec in target_fetch_registers (regcache=0x10000fea4f0, regno=80) at /home/simark/src/binutils-gdb/gdb/target.c:3287
#13 0x00000100006a8c5c in regcache::raw_update (this=0x10000fea4f0, regnum=80) at /home/simark/src/binutils-gdb/gdb/regcache.c:584
#14 0x00000100006a8d94 in readable_regcache::raw_read (this=0x10000fea4f0, regnum=80, buf=0x7feffe3b7c0 "") at /home/simark/src/binutils-gdb/gdb/regcache.c:598
#15 0x00000100006a93b8 in readable_regcache::cooked_read (this=0x10000fea4f0, regnum=80, buf=0x7feffe3b7c0 "") at /home/simark/src/binutils-gdb/gdb/regcache.c:690
#16 0x00000100006b288c in readable_regcache::cooked_read<unsigned long, void> (this=0x10000fea4f0, regnum=80, val=0x7feffe3b948) at /home/simark/src/binutils-gdb/gdb/regcache.c:777
#17 0x00000100006a9b44 in regcache_cooked_read_unsigned (regcache=0x10000fea4f0, regnum=80, val=0x7feffe3b948) at /home/simark/src/binutils-gdb/gdb/regcache.c:791
#18 0x00000100006abf3c in regcache_read_pc (regcache=0x10000fea4f0) at /home/simark/src/binutils-gdb/gdb/regcache.c:1295
#19 0x0000010000507920 in save_stop_reason (lp=0x10000fc5b10) at /home/simark/src/binutils-gdb/gdb/linux-nat.c:2612
#20 0x00000100005095a4 in linux_nat_filter_event (lwpid=520983, status=1407) at /home/simark/src/binutils-gdb/gdb/linux-nat.c:3050
#21 0x0000010000509f9c in linux_nat_wait_1 (ptid=..., ourstatus=0x7feffe3c8f0, target_options=...) at /home/simark/src/binutils-gdb/gdb/linux-nat.c:3194
#22 0x000001000050b1d0 in linux_nat_target::wait (this=0x10000fa2c40 <the_sparc64_linux_nat_target>, ptid=..., ourstatus=0x7feffe3c8f0, target_options=...) at /home/simark/src/binutils-gdb/gdb/linux-nat.c:3432
#23 0x00000100007f8ac0 in target_wait (ptid=..., status=0x7feffe3c8f0, options=...) at /home/simark/src/binutils-gdb/gdb/target.c:2000
#24 0x00000100004ac17c in do_target_wait_1 (inf=0x1000116d280, ptid=..., status=0x7feffe3c8f0, options=...) at /home/simark/src/binutils-gdb/gdb/infrun.c:3464
#25 0x00000100004ac3b8 in operator() (__closure=0x7feffe3c678, inf=0x1000116d280) at /home/simark/src/binutils-gdb/gdb/infrun.c:3527
#26 0x00000100004ac7cc in do_target_wait (wait_ptid=..., ecs=0x7feffe3c8c8, options=...) at /home/simark/src/binutils-gdb/gdb/infrun.c:3540
#27 0x00000100004ad8c4 in fetch_inferior_event () at /home/simark/src/binutils-gdb/gdb/infrun.c:3880
#28 0x0000010000485568 in inferior_event_handler (event_type=INF_REG_EVENT) at /home/simark/src/binutils-gdb/gdb/inf-loop.c:42
#29 0x000001000050d394 in handle_target_event (error=0, client_data=0x0) at /home/simark/src/binutils-gdb/gdb/linux-nat.c:4060
#30 0x0000010000ab5c8c in handle_file_event (file_ptr=0x10001207270, ready_mask=1) at /home/simark/src/binutils-gdb/gdbsupport/event-loop.cc:575
#31 0x0000010000ab6334 in gdb_wait_for_event (block=0) at /home/simark/src/binutils-gdb/gdbsupport/event-loop.cc:701
#32 0x0000010000ab487c in gdb_do_one_event () at /home/simark/src/binutils-gdb/gdbsupport/event-loop.cc:212
#33 0x0000010000542668 in start_event_loop () at /home/simark/src/binutils-gdb/gdb/main.c:348
#34 0x000001000054287c in captured_command_loop () at /home/simark/src/binutils-gdb/gdb/main.c:408
#35 0x0000010000544e84 in captured_main (data=0x7feffe3d188) at /home/simark/src/binutils-gdb/gdb/main.c:1242
#36 0x0000010000544f2c in gdb_main (args=0x7feffe3d188) at /home/simark/src/binutils-gdb/gdb/main.c:1257
#37 0x00000100000c1f14 in main (argc=4, argv=0x7feffe3d548) at /home/simark/src/binutils-gdb/gdb/gdb.c:32
There is a target_read_memory call in sparc_supply_rwindow, whose return
value is not checked. That call fails, because inferior_ptid does not
contain a valid ptid, and uninitialized buffer contents is used.
Ultimately it results in a corrupt stop_pc.
target_ops::fetch_registers can be (and should remain, in my opinion)
independent of inferior_ptid, because the ptid of the thread from which
to fetch registers can be obtained from the regcache. In other words,
implementations of target_ops::fetch_registers should not rely on
inferior_ptid having a sensible value on entry.
The sparc64_linux_nat_target::fetch_registers case is special, because it calls
a target method that is dependent on the inferior_ptid value
(target_read_inferior, and ultimately target_ops::xfer_partial). So I would
say it's the responsibility of sparc64_linux_nat_target::fetch_registers to set
up inferior_ptid correctly prior to calling target_read_inferior.
This patch makes sparc64_linux_nat_target::fetch_registers (and
store_registers, since it works the same) temporarily set inferior_ptid. If we
ever make target_ops::xfer_partial independent of inferior_ptid, setting
inferior_ptid won't be necessary, we'll simply pass down the ptid as a
parameter in some way.
I chose to set/restore inferior_ptid in sparc_fetch_inferior_registers, because
I am not convinced that doing so in an inner location (in sparc_supply_rwindow
for instance) would always be correct. We have access to the ptid in
sparc_supply_rwindow (from the regcache), so we _could_ set inferior_ptid
there. However, I don't want to just set inferior_ptid, as that would make it
not desync'ed with `current_thread ()` and `current_inferior ()`. It's
preferable to use switch_to_thread instead, as that switches all the global
"current" stuff in a coherent way. But doing so requires a `thread_info *`,
and getting a `thread_info *` from a ptid requires a `process_stratum_target
*`. We could use `current_inferior()->process_target()` in
sparc_supply_rwindow for this (using target_read_memory uses the current
inferior's target stack anyway). However, sparc_supply_rwindow is also used in
the context of BSD uthreads, where a thread stratum target defines threads. I
presume the ptid in the regcache would be the ptid of the uthread, defined by
the thread stratum target (bsd_uthread_target). Using
`current_inferior()->process_target()` would look up a ptid defined by the
thread stratum target using the process stratum target. I don't think it would
give good results. So I prefer playing it safe and looking up the thread
earlier, in sparc_fetch_inferior_registers.
I added some assertions (in sparc_supply_rwindow and others) to verify
that the regcache's ptid matches inferior_ptid. That verifies that the
caller has properly set the correct global context. This would have
caught (though a failed assertion) the current problem.
gdb/ChangeLog:
PR gdb/27147
* sparc-nat.h (sparc_fetch_inferior_registers): Add
process_stratum_target parameter,
sparc_store_inferior_registers): update callers.
* sparc-nat.c (sparc_fetch_inferior_registers,
sparc_store_inferior_registers): Add process_stratum_target
parameter. Switch current thread before calling
sparc_supply_gregset / sparc_collect_rwindow.
(sparc_store_inferior_registers): Likewise.
* sparc-obsd-tdep.c (sparc32obsd_supply_uthread): Add assertion.
(sparc32obsd_collect_uthread): Likewise.
* sparc-tdep.c (sparc_supply_rwindow, sparc_collect_rwindow):
Add assertion.
* sparc64-obsd-tdep.c (sparc64obsd_collect_uthread,
sparc64obsd_supply_uthread): Add assertion.
Change-Id: I16c658cd70896cea604516714f7e2428fbaf4301
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Christian suggested switching an "int" in ada-lang.c to "bool"
instead. This patch makes this change. Tested on x86-64 Fedora 32.
gdb/ChangeLog
2021-03-04 Tom Tromey <tromey@adacore.com>
* ada-lang.c (struct match_data) <found_sym>: Now bool.
(aux_add_nonlocal_symbols): Update.
(ada_add_block_symbols): Change "found_sym" to bool.
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This patch addresses some review comments that I forgot to deal with
in an earlier patch. See the comments here:
https://sourceware.org/pipermail/gdb-patches/2021-February/176278.html
For the most part this is fixing up comments, but it also includes
adding a constructor and initializers to "match_data".
Regression tested on x86-64 Fedora 32.
gdb/ChangeLog
2021-03-03 Tom Tromey <tromey@adacore.com>
* ada-lang.c (ada_resolve_function): Update comment.
(is_nonfunction, add_symbols_from_enclosing_procs)
(remove_extra_symbols): Likewise.
(struct match_data): Add constructor, initializers.
(add_nonlocal_symbols): Remove memset.
(aux_add_nonlocal_symbols): Update comment.
(ada_add_block_renamings, add_nonlocal_symbols)
(ada_add_all_symbols): Likewise.
* ada-exp.y (write_var_or_type): Clean up trailing whitespace.
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In gdb.btrace/rn-dl-bind.exp we test that we can reverse-step over
recorded dynamic linking. The test covers specific behaviour to support
_dl_runtime_resolve calling the resolved function by returning to it.
This would normally mess up stepping as we'd end up with backtraces that
contain the same functions but different frame ids.
Since GDB needs to recognize a return from _dl_runtime_resolve, the test
only passes when debug information for _dl_runtime_resolve is available.
The test requires that symbols are bound lazily. Otherwise, we won't
record dynamic linking and the test will be fairly pointless.
Recent GCC pass -z now by default to bind symbols eagerly. Add -z lazy to
the test's ldflags to enforce lazy binding.
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In gdb.btrace/non-stop.exp, we hard-code expected source lines assuming we
know how they would match to the recorded trace. Despite the fact that we
should really have been using an assembly source, the assumptions work
pretty well.
With clang-6 -m32, we found a case where the assumptions do not hold.
Adjust the expected source lines a little bit to cover that case, as well.
Should we run into more cases like this, we will have to switch to an
assembly source file.
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We use pre-compiled assembly including debug information for stepi, yet we
compiled with -g, which was implicitly set by prepare_for_testing.
Add {} options to avoid the implicit {debug}.
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Clang generates slightly different debug information. Adjust the expected
output of gdb.btrace/function_call_history.exp to work with both gcc and
clang.
Also modify gdb.btrace/exception.cc to reliably trace into main and update
the corresponding patterns in gdb.btrace/exception.exp.
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In gdb.btrace/unknown_functions.exp we need the linker to discard local
symbols so GDB wouldn't know about them from the symbol table.
When building with clang, it complains about the option not being used at
compile-time. Move the option to ldflags to only pass it at link-time.
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Clang generates slightly different debug information causing
gdb.btrace/rn-dl-bind.exp to fail on its way to the actual test.
Modify the test to remove that dependency.
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In gdb.btrace/delta.exp, we test that we do not extend the trace
unintentionally. This can be tested by checking the number of
instructions.
If we wanted to check the instruction history, as well, we'd need to work
on an assembly file to have deterministic behaviour. This isn't really
necessary for this test, however, and covered elsewhere. Also remove the
function call history check for the same reason.
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Some older GCC, e.g. 7.5.0 on Ubuntu 18.04 need -fno-pie to be passed to
the compiler in addition to -no-pie to be passed to the linker for non-pie
code generation.
The gdb,nopie_flag is already documented as getting passed to the
compiler, not the linker. Use that for the new -fno-pie compiler flag and
add a new gdb,nopie_ldflag for the existing -no-pie linker flag.
CAUTION: this might break existing board files that specify
gdb,nopie_flag. Affected board files need to rename
gdb,nopie_flag into gdb,nopie_ldflag.
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gdb currently supports two different styles of fixed-point. The
original style, where fixed point types are "GNAT encoded", is handled
primarily in the Ada code. The newer style, encoded using DWARF, is
handled by the core of gdb.
This patch changes gdb to read the GNAT encodings in the DWARF reader
as well. This removes some code and unifies the two paths. As a
result, GNAT-encoded fixed-point now works a bit better.
One possible drawback of this change is that, if someone uses stabs,
then fixed-point might now stop working. I consider stabs to be fully
obsolete, though, so I don't intend to address this.
gdb/ChangeLog
2021-03-02 Tom Tromey <tromey@adacore.com>
* ada-lang.c (cast_from_gnat_encoded_fixed_point_type)
(cast_to_gnat_encoded_fixed_point_type): Remove.
(ada_value_cast, ada_evaluate_subexp): Update.
(gnat_encoded_fixed_point_type_info)
(ada_is_gnat_encoded_fixed_point_type)
(gnat_encoded_fixed_point_delta)
(gnat_encoded_fixed_point_scaling_factor): Remove.
* ada-lang.h (ada_is_gnat_encoded_fixed_point_type)
(gnat_encoded_fixed_point_delta)
(gnat_encoded_fixed_point_scaling_factor): Don't declare.
* ada-typeprint.c (print_gnat_encoded_fixed_point_type): Remove.
(ada_print_type): Update.
* ada-valprint.c (ada_value_print_num): Update.
* dwarf2/read.c (ada_get_gnat_encoded_number)
(ada_get_gnat_encoded_ratio): New functions.
(finish_fixed_point_type): Use them. Add parameters.
(GNAT_FIXED_POINT_SUFFIX): New define.
(gnat_encoded_fixed_point_type_info): New function.
(read_base_type): Handle gnat encodings.
gdb/testsuite/ChangeLog
2021-03-02 Tom Tromey <tromey@adacore.com>
* gdb.ada/fixed_points.exp: Remove most special cases for minimal
encodings.
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This removes the "GROW_VECT" macro and helper function in favor of
simply using std::string in a few spots.
gdb/ChangeLog
2021-03-02 Tom Tromey <tromey@adacore.com>
* ada-lang.c (ada_fold_name, ada_variant_discrim_name)
(ada_enum_name, scan_discrim_bound, to_fixed_range_type): Use
std::string.
(GROW_VECT): Remove.
(grow_vect): Remove.
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This changes ada_lookup_symbol_list to return a std::vector, and
changes various other helper functions to follow. This simplifies the
code, and makes it more type-safe (by using a vector where an obstack
had been used).
gdb/ChangeLog
2021-03-02 Tom Tromey <tromey@adacore.com>
* ada-lang.h (ada_lookup_symbol_list): Return a vector.
* ada-lang.c (resolve_subexp): Update.
(ada_resolve_function): Accept a vector.
(is_nonfunction, add_defn_to_vec)
(add_symbols_from_enclosing_procs): Likewise.
(num_defns_collected, defns_collected): Remove.
(remove_extra_symbols): Return a vector.
(remove_irrelevant_renamings): Return void.
(ada_add_local_symbols): Accept a vector.
(struct match_data) <obstackp>: Remove.
<resultp>: New member.
(aux_add_nonlocal_symbols): Update.
(ada_add_block_renamings, add_nonlocal_symbols)
(ada_add_all_symbols): Accept a vector.
(ada_lookup_symbol_list_worker, ada_lookup_symbol_list): Return a
vector.
(ada_lookup_symbol): Update.
(ada_add_block_symbols): Accept a vector.
(get_var_value, iterate_over_symbols): Update.
* ada-exp.y (block_lookup, write_var_or_type, write_name_assoc):
Update.
|
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This changes resolve_subexp to use any_of and the erase-remove idiom
to simplify the code somewhat. This simplifies the next patch a bit.
gdb/ChangeLog
2021-03-02 Tom Tromey <tromey@adacore.com>
* ada-lang.c (resolve_subexp): Use any_of and erase-remove idiom.
|
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This changes the ada_symbol_cache to be allocated with 'new' and
managed via unique_ptr. This simplifies the code somewhat. Also,
ada_clear_symbol_cache is changed so that it does not allocate a
symbol cache just to clear it.
gdb/ChangeLog
2021-03-02 Tom Tromey <tromey@adacore.com>
* ada-lang.c (struct ada_symbol_cache) <cache_space>: Now an
auto_obstack.
<root>: Initialize.
(ada_pspace_data): Remove destructor.
<sym_cache>: Now a unique_ptr.
(ada_init_symbol_cache, ada_free_symbol_cache): Remove.
(ada_get_symbol_cache): Use 'new'.
(ada_clear_symbol_cache): Rewrite.
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Most places in gdb that reference objfile->sf also check that it is
not null. It is valid for it to be null, because find_sym_fns can
return null for some kinds of object file. However, it's rare to
encounter this scenario with Ada code. I only encountered it when
looking at a fork of gdb that, I believe, makes its own objfiles
without setting 'sf'.
This patch changes ada-lang.c to check this field before using it.
This avoids any potential crash here. There's no test case because
I'm not even sure this is possible to trip over with an unmodified
gdb.
There are some other unchecked uses in gdb, but at a quick glance they
all seem to be involved with symbol reading, which of course won't
happen when sf==null.
gdb/ChangeLog
2021-03-02 Tom Tromey <tromey@adacore.com>
* ada-lang.c (add_nonlocal_symbols): Handle case where objfile->sf
is null.
|
|
As reported in gdb/27393, the 'directory' and 'set directories' commands
fail when parsing an empty dir name:
(gdb) set directories ""
/home/lsix/dev/gnu/binutils-gdb/gdbsupport/pathstuff.cc:132: internal-error: gdb::unique_xmalloc_ptr<char> gdb_abspath(const char*): Assertion `path != NULL && path[0] != '\0'' failed.
or
(gdb) dir :
/home/lsix/dev/gnu/binutils-gdb/gdbsupport/pathstuff.cc:132: internal-error: gdb::unique_xmalloc_ptr<char> gdb_abspath(const char*): Assertion `path != NULL && path[0] != '\0'' failed.
This patch fixes this issue by ignoring any attempt to add an empty
name to the source directories list. 'set dir ""' will reset the
directories list the same way 'set dir' would do it.
Tested on x86_64.
|
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I noticed an oddity in skip_ctf_tests -- for me it ends up caching the
string "!0", because it ends with 'return ![...]'. In Tcl, this is
just string concatenation.
The result works because the users of this function have unbraced if
conditions, like:
if [skip_ctf_tests] {
... which works because "if" re-parses the returned string as an
expression, and evaluates that.
There's only a latent bug here, but this is also un-idiomatic, so I am
checking in this patch to fix it. This way, if someone in the future
uses a braced condition (which is what I normally recommend), it will
continue to work.
gdb/testsuite/ChangeLog
2021-02-26 Tom Tromey <tom@tromey.com>
* lib/gdb.exp (skip_ctf_tests): Use expr on result.
|
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Commit 2450ad54 removed extra trailing \n from tsv notifications but
did not update gdb.trace/mi-tsv-changed.exp accordingly. This commit
removes the extra \n from expected output so gdb.trace/mi-tsv-changed.exp
passes again.
gdb/testsuite/ChangeLog:
* gdb.trace/mi-tsv-changed.exp (test_create_delete_modify_tsv):
Remove trailing \n from expected output.
|
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Add a note to the comment on use_gdb_stub explaining the use of this check
for skipping tests that spawn new inferiors as discussed here:
https://sourceware.org/pipermail/gdb-patches/2020-December/174186.html
|
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|
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I added the same comment for nat/aarch64-linux-hw-point.c yesterday.
Christian suggested adding the comment for the other file that I had
identified as including both <sys/ptrace.h> and <asm/ptrace.h>.
I searched the sources in gdb/, but found no other files which include
both of these headers.
If possible, I would prefer to see us use <sys/ptrace.h> when possible,
however, from past experience, I've found that this file does not always
contain all of the constants, etc. required by the particular source
file.
gdb/ChangeLog:
* nat/aarch64-sve-linux-ptrace.h: Add comment regarding include
order for <sys/ptrace.h> and <asm/ptrace.h>.
|
|
As reported in PR 26861, when killing an inferior on macOS, we hit the
assert:
../../gdb-10.1/gdb/target.c:2149: internal-error: void target_mourn_inferior(ptid_t): Assertion `ptid == inferior_ptid' failed.
This is because darwin_nat_target::kill passes a pid-only ptid to
target_mourn_inferior, with the pid of the current inferior:
target_mourn_inferior (ptid_t (inf->pid));
... which doesn't satisfy the assert in target_mourn_inferior:
gdb_assert (ptid == inferior_ptid);
The reason for this assertion is that target_mourn_inferior is a
prototype shared between GDB and GDBserver, so that shared code in
gdb/nat (used in both GDB and GDBserver) can call target_mourn_inferior.
In GDB's implementation, it is likely that some targets still rely on
inferior_ptid being set to "the current thread we are working on". So
until targets are completely decoupled from inferior_ptid (at least
their mourn_inferior implementations), we need to ensure the passed in
ptid matches inferior_ptid, to ensure the calling code called
target_mourn_inferior with the right global context.
However, I think the assert is a bit too restrictive. The
mourn_inferior operation works on an inferior, not a specific thread.
And by the time we call mourn_inferior, the threads of the inferior
don't exist anymore, the process is gone, so it doesn't really make
sense to require inferior_ptid to point a specific thread.
I looked at all the target_ops::mourn_inferior implementations, those
that read inferior_ptid only care about the pid field, which supports
the idea that only the inferior matters. Other implementations look at
the current inferior (call `current_inferior ()`).
I think it would make sense to change target_mourn_inferior to accept
only a pid rather than a ptid. It would then assert that the pid is the
same as the current inferior's pid. However, this would be a quite
involved change, so I'll keep it for later.
To fix the macOS issue immediately, I propose to relax the assert to
only compare the pids, as is done in this patch.
Another solution would obviously be to make darwin_nat_target::kill pass
inferior_ptid to target_mourn_inferior. However, the solution I propose
is more in line with where I think we want to go (passing a pid to
target_mourn_inferior).
gdb/ChangeLog:
PR gdb/26861
* target.c (target_mourn_inferior): Only compare pids in
target_mourn_inferior.
Change-Id: If2439ccc5aa67272ea16148a43c5362ef23fb2b8
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This change fixes the initial state of the main thread of remote
targets which have no concept of threading. Such targets are
treated as single-threaded by gdb, and this single thread needs
to be initially set to the "resumed" state, in the same manner as
threads in thread-aware remote targets (see remote.c,
remote_target::remote_add_thread).
Without this fix, the following assert was triggered on thread-
unaware remote targets:
remote_target::select_thread_for_ambiguous_stop_reply(const target_waitstatus*): Assertion `first_resumed_thread != nullptr' failed.
The bug can be reproduced using gdbserver
* by disabling packets 'T' and 'qThreadInfo', or
* by disabling all thread-related packets.
The test suite has been updated to include these two scenarios, see
gdb.server/stop-reply-no-thread.exp.
Change-Id: I2c39c9de17e8d6922a8c1b9e259eb316a554a43d
|
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In commit:
commit faeb9f13c179a4c78bc295a0d0bbd788239704d9
Date: Wed Feb 24 12:50:00 2021 +0000
gdb/fortran: add support for ASSOCIATED builtin
A test was added that fails to process the trailing gdb prompt inside
a gdb_test_multiple call, this will cause a failure if the tests are
run with READ1=1, or randomly at other times depending on how the
expect buffers are read in.
Fixed by adding a -wrap argument.
gdb/testsuite/ChangeLog:
* gdb.fortran/associated.exp: Add missing '-wrap' argument.
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An extra \n in calls to fprintf_unfiltered() caused invalid MI records
to be emitted:
> gdb -i mi3 -ex "target remote :7000"
=thread-group-added,id="i1"
~"GNU gdb (GDB) 11.0.50.20201019-git\n"
~"Copyright (C) 2020 Free Software Foundation, Inc.\n"
...
~"Remote debugging using :7001\n"
=tsv-created,name="trace_timestamp",initial="0"\n
=thread-group-started,id="i1",pid="304973"
This commit fixes the problem.
gdb/ChangeLog:
* gdb/mi/mi-interp.c (mi_traceframe_changed): Remove trailing \n from output.
(mi_tsv_created): Likewise.
(mi_tsv_deleted): Likewise.
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When running test-case gdb.dwarf2/fission-mix.exp using gcc-11 (and using the
tentative fix for PR27353 to get past that assertion failure), I run into:
...
(gdb) file fission-mix^M
Reading symbols from fission-mix...^M
Dwarf Error: wrong unit_type in compilation unit header \
(is DW_UT_split_compile (0x05), should be DW_UT_type (0x02)) \
[in module fission-mix2.dwo]^M
(No debugging symbols found in fission-mix)^M
...
The compilation unit that is complained about is:
...
Contents of the .debug_info.dwo section (loaded from fission-mix2.dwo):
Compilation Unit @ offset 0x0:
Length: 0x57 (32-bit)
Version: 5
Unit Type: DW_UT_split_compile (5)
Abbrev Offset: 0x0
Pointer Size: 8
DWO ID: 0x3e3930d3cc1805df
<0><14>: Abbrev Number: 1 (DW_TAG_compile_unit)
...
And the dwarf error is triggered here in read_comp_unit_head:
...
case DW_UT_split_compile:
if (section_kind != rcuh_kind::COMPILE)
error (_("Dwarf Error: wrong unit_type in compilation unit header "
"(is %s, should be %s) [in module %s]"),
dwarf_unit_type_name (cu_header->unit_type),
dwarf_unit_type_name (DW_UT_type), filename);
break;
...
due to passing rcuh_kind::TYPE here in open_and_init_dwo_file:
...
create_debug_type_hash_table (per_objfile, dwo_file.get (),
&dwo_file->sections.info, dwo_file->tus,
rcuh_kind::TYPE);
...
Fix this by changing the section_kind argument to create_debug_type_hash_table
to rcuh_kind::COMPILE, to reflect that we're passing &dwo_file->sections.info
rather than &dwo_file->sections.types.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-25 Tom de Vries <tdevries@suse.de>
PR symtab/27354
* dwarf2/read.c (open_and_init_dwo_file): Use rcuh_kind::COMPILE as
section_kind for &dwo_file->sections.info.
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When attempting to call a Fortran function for which there is no debug
information we currently trigger undefined behaviour in GDB by
accessing non-existent type fields.
The reason is that in order to prepare the arguments, for a call to a
Fortran function, we need to know the type of each argument. If the
function being called has no debug information then obviously GDB
doesn't know about the argument types and we should either give the
user an error or pick a suitable default. What we currently do is
just assume the field exist and access undefined memory, which is
clearly wrong.
The reason GDB needs to know the argument type is to tell if the
argument is artificial or not, artificial arguments will be passed by
value while non-artificial arguments will be passed by reference.
An ideal solution for this problem would be to allow the user to cast
the function to the correct type, we already do this to some degree
with the return value, for example:
(gdb) print some_func_ ()
'some_func_' has unknown return type; cast the call to its declared return type
(gdb) print (integer) some_func_ ()
$1 = 1
But if we could extend this to allow casting to the full function
type, GDB could figure out from the signature what are real
parameters, and what are artificial parameters. Maybe something like
this:
(gdb) print ((integer () (integer, double)) some_other_func_ (1, 2.3)
Alas, right now the Fortran expression parser doesn't seem to support
parsing function signatures, and we certainly don't have support for
figuring out real vs artificial arguments from a signature.
Still, I think we can prevent GDB from accessing undefined memory and
provide a reasonable default behaviour.
In this commit I:
- Only ask if the argument is artificial if the type of the argument
is actually known.
- Unknown arguments are assumed to be artificial and passed by
value (non-artificial arguments are pass by reference).
- If an artificial argument is prefixed with '&' by the user then we
treat the argument as pass-by-reference.
With these three changes we avoid undefined behaviour in GDB, and
allow the user, in most cases, to get a reasonably natural default
behaviour.
gdb/ChangeLog:
PR fortran/26155
* f-lang.c (fortran_argument_convert): Delete declaration.
(fortran_prepare_argument): New function.
(evaluate_subexp_f): Move logic to new function
fortran_prepare_argument.
gdb/testsuite/ChangeLog:
PR fortran/26155
* gdb.fortran/call-no-debug-func.f90: New file.
* gdb.fortran/call-no-debug-prog.f90: New file.
* gdb.fortran/call-no-debug.exp: New file.
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This commit adds support for the ASSOCIATED builtin to the Fortran
expression evaluator. The ASSOCIATED builtin takes one or two
arguments.
When passed a single pointer argument GDB returns a boolean indicating
if the pointer is associated with anything.
When passed two arguments the second argument should either be some a
pointer could point at or a second pointer.
If the second argument is a pointer target, then the result from
associated indicates if the pointer is pointing at this target.
If the second argument is another pointer, then the result from
associated indicates if the two pointers are pointing at the same
thing.
gdb/ChangeLog:
* f-exp.y (f77_keywords): Add 'associated'.
* f-lang.c (fortran_associated): New function.
(evaluate_subexp_f): Handle FORTRAN_ASSOCIATED.
(operator_length_f): Likewise.
(print_unop_or_binop_subexp_f): New function.
(print_subexp_f): Make use of print_unop_or_binop_subexp_f for
FORTRAN_ASSOCIATED, FORTRAN_LBOUND, and FORTRAN_UBOUND.
(dump_subexp_body_f): Handle FORTRAN_ASSOCIATED.
(operator_check_f): Likewise.
* std-operator.def: Add FORTRAN_ASSOCIATED.
gdb/testsuite/ChangeLog:
* gdb.fortran/associated.exp: New file.
* gdb.fortran/associated.f90: New file.
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gfortran supports .xor. as an alias for .neqv., see:
https://gcc.gnu.org/onlinedocs/gfortran/_002eXOR_002e-operator.html
this commit adds support for this operator to GDB.
gdb/ChangeLog:
* f-exp.y (fortran_operators): Add ".xor.".
gdb/testsuite/ChangeLog:
* gdb.fortran/dot-ops.exp (dot_operations): Test ".xor.".
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With test-case gdb.cp/temargs.exp on target board \
unix/gdb:debug_flags=-gdwarf-5 I run into:
...
(gdb) info addr I^M
ERROR: GDB process no longer exists
GDB process exited with wait status 32286 exp19 0 0 CHILDKILLED SIGABRT SIGABRT
UNRESOLVED: gdb.cp/temargs.exp: test address of I in templ_m
...
This is a regression since commit 529908cbd0a "Remove DW_UNSND".
The problem is that this DW_AT_decl_file:
...
<1><221>: Abbrev Number: 4 (DW_TAG_structure_type)
<222> DW_AT_name : Base<double, 23, (& a_global), &S::f>
<226> DW_AT_byte_size : 1
<226> DW_AT_decl_file : 1
<226> DW_AT_decl_line : 30
<227> DW_AT_sibling : <0x299>
...
is not read by this code in new_symbol:
....
attr = dwarf2_attr (die,
inlined_func ? DW_AT_call_file : DW_AT_decl_file,
cu);
if (attr != nullptr && attr->form_is_unsigned ())
...
because DW_AT_decl_file has form DW_FORM_implicit_const:
...
4 DW_TAG_structure_type [has children]
DW_AT_name DW_FORM_strp
DW_AT_byte_size DW_FORM_implicit_const: 1
DW_AT_decl_file DW_FORM_implicit_const: 1
DW_AT_decl_line DW_FORM_data1
DW_AT_sibling DW_FORM_ref4
DW_AT value: 0 DW_FORM value: 0
...
which is a signed LEB128, so attr->form_is_unsigned () returns false.
Fix this by introducing new functions is_nonnegative and as_nonnegative, and
use these instead of form_is_unsigned and as_unsigned.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-24 Tom de Vries <tdevries@suse.de>
PR symtab/27336
* dwarf2/attribute.c (attribute::form_is_signed): New function
factored out of ...
* dwarf2/attribute.h (attribute::as_signed): ... here.
(attribute::is_nonnegative, attribute::as_nonnegative): New function.
(attribute::form_is_signed): Declare.
* dwarf2/read.c (new_symbol): Use is_nonnegative and as_nonnegative
for DW_AT_decl_file.
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gdb/ChangeLog:
* nat/aarch64-linux-hw-point.c: Add comment regarding include
order for <sys/ptrace.h> and <asm/ptrace.h>.
|
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Due to a recent glibc header file change, the file
nat/aarch64-linux-hw-point.c no longer builds on Fedora rawhide.
An enum for PTRACE_SYSEMU is now provided by <sys/ptrace.h>. In the
past, PTRACE_SYSEMU was defined only in <asm/ptrace.h>. This is
what it looks like...
In <asm/ptrace.h>:
#define PTRACE_SYSEMU 31
In <sys/ptrace.h>:
enum __ptrace_request
{
...
PTRACE_SYSEMU = 31,
#define PT_SYSEMU PTRACE_SYSEMU
...
}
When <asm/ptrace.h> and <sys/ptrace.h> are both included in a source
file, we run into the following build problem when the former is
included before the latter:
In file included from nat/aarch64-linux-hw-point.c:26:
/usr/include/sys/ptrace.h:86:3: error: expected identifier before numeric constant
86 | PTRACE_SYSEMU = 31,
| ^~~~~~~~~~~~~
(There are more errors after this one too.)
The file builds without error when <asm/ptrace.h> is included after
<sys/ptrace.h>. I found that this is already done in
nat/aarch64-sve-linux-ptrace.h (which is included by
nat/aarch64-linux-ptrace.c).
I've tested this change on Fedora rawhide and Fedora 33, both
running on an aarch64 machine.
gdb/ChangeLog:
* nat/aarch64-linux-hw-point.c: Include <asm/ptrace.h> after
<sys/ptrace.h>.
|
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The 'section' command uses a fixed size buffer into which a section
name is copied. This commit replaces this with a use of std::string
so we can now display very long section names.
The expected results of one test need to be updated.
gdb/ChangeLog:
* exec.c (set_section_command): Move variable declarations into
the function body, and use std::string instead of a fixed size
buffer.
gdb/testsuite/ChangeLog:
* gdb.base/sect-cmd.exp: Update expected results.
|
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The only target that implements target_ops::get_section_table in a
meaningful way is exec_target. This target calls back into the
program space to return the current global section_table.
The global section table is populated whenever the user provides GDB
with an executable, or when a symbol file is loaded, e.g. when a
dynamic library is loaded, or when the user does add-symbol-file.
I recently ran into a situation where a user, debugging a remote
target, was not supplying GDB with a main executable at all. Instead
the user attached to the target then did add-symbol-file, and then
proceeded to debug the target.
This works fine, but it was noticed that even when
trust-readonly-sections was on GDB was still accessing the target to
get the contents of readonly sections.
The problem is that by not providing an executable there was no
exec_target in the target stack, and so when GDB calls the
target_ops::get_section_table function GDB ends up in
dummy_target::get_section_table, which just returns NULL.
What I want is that even when GDB doesn't have an exec_target in the
target stack, a call to target_ops::get_section_table will still
return the section_table from the current program space.
When considering how to achieve this my first though was, why is the
request for the section table going via the target stack at all? The
set of sections loaded is a property of the program space, not the
target. This is, after all, why the data is being stored in the
program space.
So I initially tried changing target_get_section_table so that,
instead of calling into the target it just returns
current_program_space->target_sections ().
This would be fine except for one issue, target_bfd (from
bfd-target.c). This code is used from solib-svr4.c to create a
temporary target_ops structure that implements two functions
target_bfd::xfer_partial and target_bfd::get_section_table.
The purpose behind the code is to enable two targets, ppc64 and frv to
decode function descriptors from the dynamic linker, based on the
non-relocated addresses from within the dynamic linker bfd object.
Both of the implemented functions in target_bfd rely on the target_bfd
object holding a section table, and the ppc64 target requires that the
target_bfd implement ::get_section_table.
The frv target doesn't require ::get_section_table, instead it
requires the ::xfer_partial. We could in theory change the ppc64
target to use the same approach as frv, however, this would be a bad
idea. I believe that the frv target approach is broken. I'll
explain:
The frv target calls get_target_memory_unsigned to read the function
descriptor. The address being read is the non-relocated address read
from the dynamic linker in solib-srv4.c:enable_break. Calling
get_target_memory_unsigned eventually ends up in target_xfer_partial
with an object type of TARGET_OBJECT_RAW_MEMORY. This will then call
memory_xfer_check_region. I believe that it is quite possible that a
the non-relocated addresses pulled from the dynamic linker could be in
a memory region that is not readable, while the relocated addresses
are in a readable memory region. If this was ever the case for the
frv target then GDB would reject the attempt to read the non-relocated
function pointer.
In contrast the ppc64 target calls target_section_by_addr, which calls
target_get_section_table, which then calls the ::get_section_table
function on the target.
Thus, when reflecting on target_bfd we see two functions,
::xfer_partial and ::get_section_table. The former is required by the
frv target, but that target is (I think) potentially broken. While
the latter is required by the ppc64 target, but this forces
::get_section_table to exist as a target_ops member function.
So my original plan, have target_get_section_table NOT call a
target_ops member function appears to be flawed.
My next idea was to remove exec_target::get_section_table, and instead
move the implementation into dummy_target::get_section_table.
Currently the dummy_target implementation always returns NULL
indicating no section table, but plenty of other dummy_target member
functions do more than just return null values.
So now, dummy_target::get_section_table returns the section table from
the current program space. This allows target_bfd to remain
unchanged, so ppc64 and frv should not be affected.
Making this change removes the requirement for the user to provide an
executable, GDB can now always access the section_table, as the
dummy_target always exists in the target stack.
Finally, there's a test that the target_section table is not empty in
the case where the user does add-symbol-file without providing an
executable.
gdb/ChangeLog:
* exec.c (exec_target::get_section_table): Delete member function.
(section_table_read_available_memory): Use current_top_target, not
just the exec_ops target.
* target-delegates.c: Regenerate.
* target.c (default_get_section_table): New function.
* target.h (target_ops::get_section_table): Change default
behaviour to call default_get_section_table.
(default_get_section_table): Declare.
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Following on from earlier commits which made access to the
target_sections table more 'const', this commit makes the table
private within the program_space class and provides member functions
to access the table.
Ideally I would have liked for the new target_sections member
function (on program_space) to return a 'const' reference to the table
within the program_space. Unfortunately, there are two places in
solib-*.c, where code outside of the program_space class modifies the
target_sections table, and so to support this we need to return a
non-const reference.
There should be no user visible changes after this commit.
gdb/ChangeLog:
* exec.c (exec_target::close): Call new clear_target_sections
function.
(program_space::add_target_sections): Update name of member
variable.
(program_space::foreach_target_section): New function.
(program_space::add_target_sections): Update name of member
variable.
(program_space::remove_target_sections): Likewise.
(exec_one_fork): Use new target_sections member function.
(exec_target::get_section_table): Likewise.
(exec_target::files_info): Likewise.
(set_section_command): Use new foreach_target_section member
function.
(exec_set_section_address): Likewise.
(exec_target::has_memory): Use new target_sections member
function.
* progspace.h (program_space::clear_target_sections): New member
function.
(program_space::target_sections): Rename member variable to
m_target_sections, replace with a new member function.
(program_space::foreach_target_section): Declare new member
function.
(program_space::m_target_sections): New member variable.
* solib-dsbt.c (scan_dyntag): Use new member function.
* solib-svr4.c (scan_dyntag): Likewise.
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During review of the next patch (which changes the 'section' command),
a bug was pointed out. I wondered why no tests spotted this bug and I
found that the 'section' command test (sect-cmd.exp) is only run on
hppa targets!
In this commit I have given this test script a bit of a spring clean,
bringing it up to date with current testsuite style. I have made some
of the patterns a little more robust, but in general my intention was
not to change the underlying meaning of any of these tests.
gdb/testsuite/ChangeLog:
* gdb.base/sect-cmd.exp: Rewrite using modern testsuite
techniques. Enable the test for all targets.
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The code to access the target section table can be made more const, so
lets do that. There should be no user visible changes after this
commit.
gdb/ChangeLog:
* gdb/bfd-target.c (class target_bfd) <get_section_table>: Make
return type const.
* gdb/exec.c (struct exec_target) <get_section_table>: Likewise.
(section_table_read_available_memory): Make local const.
(exec_target::xfer_partial): Make local const.
(print_section_info): Make parameter const.
* gdb/exec.h (print_section_info): Likewise.
* gdb/ppc64-tdep.c (ppc64_convert_from_func_ptr_addr): Make local
const.
* gdb/record-btrace.c (record_btrace_target::xfer_partial):
Likewise.
* gdb/remote.c (remote_target::remote_xfer_live_readonly_partial):
Likewise.
* gdb/s390-tdep.c (s390_load): Likewise.
* gdb/solib-dsbt.c (scan_dyntag): Likewise.
* gdb/solib-svr4.c (scan_dyntag): Likewise.
* gdb/target-debug.h (target_debug_print_target_section_table_p):
Rename to...
(target_debug_print_const_target_section_table_p): ...this.
* gdb/target-delegates.c: Regenerate.
* gdb/target.c (target_get_section_table): Make return type const.
(target_section_by_addr): Likewise. Also make some locals const.
(memory_xfer_partial_1): Make some locals const.
* gdb/target.h (struct target_ops) <get_section_table>: Make
return type const.
(target_section_by_addr): Likewise.
(target_get_section_table): Likewise.
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We already have a command 'maint info sections', this command prints
all sections from all known object files.
However, GDB maintains a second section table internally. This
section table is used when GDB wants to read directly from an object
file rather than actually reading memory on the target. As such only
some sections (the allocatable ones) are added to this secondary
section table.
I recently ran into a situation where some of GDB's optimisations for
reading directly from the files were not working. In 'maint info
sections' I could see that GDB knew about the object file, and did
know about the sections that it _should_ have been reading from. But
I couldn't ask GDB which sections it had copied into its secondary
section table.
This commit adds a new command 'maint info target-sections' that fills
this gap. This command lists only those sections that GDB has copied
into its secondary table.
You'll notice that the testsuite includes a comment indicating that
there's a bug in GDB. Normally this is not something I would add to
the testsuite, instead we should raise an actual bugzilla bug and then
mark an xfail, however, a later patch in this series will remove this
comment once the actual bug in GDB is fixed.
gdb/ChangeLog:
* NEWS: Mention new 'maint info target-sections' command.
* maint.c (maintenance_info_target_sections): New function.
(_initialize_maint_cmds): Register new command.
gdb/doc/ChangeLog:
* gdb.texinfo (Files): Document new 'maint info target-sections'
command.
gdb/testsuite/ChangeLog:
* gdb.base/maint-info-sections.exp: Add new tests.
(check_maint_info_target_sections_output): New proc.
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GDB for RISC-V always uses target descriptions. When the target
doesn't provide a target description then a default is selected.
Usually this default is selected based on the properties of the
executable being debugged. However, when there is no executable being
debugged we currently fallback to the riscv:rv64 target description as
the default. This leads to strange behaviour like this:
$ gdb
(gdb) set architecture riscv:rv32
(gdb) p sizeof ($pc)
$1 = 8
Despite the users specifically setting the architecture to riscv:rv32
GDB still thinks that the target has riscv:rv64 register sizes.
The above is a bit of a contrived situation. I actually ran into this
situation while trying to connect to a running riscv:rv32 target
without supplying an executable (the target didn't provide a target
description). When I tried to set a register on the target I ran into
errors because GDB was passing 8 bytes to the target rather than the
expected 4. Even when I manually specified the architecture (as
above) I couldn't convince GDB to only send 4 bytes.
This patch fixes this issue. Now, when we selected a default target
description we will make use of the user selected architecture to
guide our choice. In the above example we now get:
$ gdb
(gdb) set architecture riscv:rv32
(gdb) p sizeof ($pc)
$1 = 4
And my real world example of connecting to a remote without an
executable works fine.
I've used the fact that we can ask GDB about $pc even when no
executable is loaded as the basis for a test to cover this situation.
gdb/ChangeLog:
* riscv-tdep.c (riscv_features_from_gdbarch_info): Rename to...
(riscv_features_from_bfd): ...this. Change parameter type to
'bfd*', and update as required.
(riscv_find_default_target_description): Update call to
riscv_features_from_bfd. Select a default xlen based on
info.bfd_arch_info.
(riscv_gdbarch_init): Update call to riscv_features_from_bfd.
gdb/testsuite/ChangeLog:
* gdb.arch/riscv-default-tdesc.exp: New file.
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When evaluating and expression containing UNOP_IND in mode
EVAL_AVOID_SIDE_EFFECTS, GDB currently (mostly) returns the result of
a call to value_zero meaning we get back an object with the correct
type, but its contents are all zero.
If the target type contains fields with dynamic type then in order to
resolve these dynamic fields GDB will need to read the value of the
field from within the parent object. In this case the field value
will be zero as a result of the call to value_zero mentioned above.
The idea behind EVAL_AVOID_SIDE_EFFECTS is to avoid the chance that
doing something like `ptype` will modify state within the target, for
example consider: ptype i++.
However, there is already precedence within GDB that sometimes, in
order to get accurate type results, we can't avoid reading from the
target, even when EVAL_AVOID_SIDE_EFFECTS is in effect. For example I
would point to eval.c:evaluate_var_value, the handling of OP_REGISTER,
the handling of value_x_unop in many places. I believe the Ada
expression evaluator also ignore EVAL_AVOID_SIDE_EFFECTS in some
cases.
I am therefor proposing that, in the case where a pointer points at a
dynamic type, we allow UNOP_IND to perform the actual indirection.
This allows accurate types to be displayed in more cases.
gdb/ChangeLog:
* eval.c (evaluate_subexp_standard): Call value_ind for points to
dynamic types in UNOP_IND.
gdb/testsuite/ChangeLog:
* gdb.fortran/pointer-to-pointer.exp: Additional tests.
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As described in the log of patch "gdb/dwarf: add assertion in
maybe_queue_comp_unit", it would happen that a call to
maybe_queue_comp_unit would enqueue a CU in the to-expand queue while
nothing up the stack was processing the queue. This is not desirable,
as items are then left lingering in the queue when we exit the
dwarf2/read code. This is an inconsistent state.
The normal case of using the queue is when we go through
dw2_do_instantiate_symtab and process_queue. As depended-on CUs are
found, they get added to the queue. process_queue expands CUs until the
queue is empty.
To catch these cases where things are enqueued while nothing up the
stack is processing the queue, change dwarf2_per_bfd::queue to be an
optional. The optional is instantiated in dwarf2_queue_guard, just
before where we call process_queue. In the dwarf2_queue_guard
destructor, the optional gets reset. Therefore, the queue object is
instantiated only when something up the stack is handling it. If
another entry point tries to enqueue a CU for expansion, an assertion
will fail and we know we have something to fix.
dwarf2_queue_guard sounds like the good place for this, as it's
currently responsible for making sure the queue gets cleared if we exit
due to an error.
This also allows asserting that when age_comp_units or remove_all_cus
run, the queue is not instantiated, and gives us one more level of
assurance that we won't free the DIEs of a CU that is in the
CUs-to-expand queue.
gdb/ChangeLog:
PR gdb/26828
* dwarf2/read.c (dwarf2_queue_guard) <dwarf2_queue_guard>:
Instantiate queue.
(~dwarf2_queue_guard): Clear queue.
(queue_comp_unit): Assert that queue is
instantiated.
(process_queue): Adjust.
* dwarf2/read.h (struct dwarf2_per_bfd) <queue>: Make optional.
Change-Id: I8fe3d77845bb4ad3d309eac906acebe79d9f0a9d
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The previous commit log described how items could be left lingering in
the dwarf2_per_bfd::queue and how that could cause trouble.
This patch fixes the issue by changing maybe_queue_comp_unit so that it
doesn't put a CU in the to-expand queue if that CU is already expanded.
This will make it so that when dwarf2_fetch_die_type_sect_off calls
follow_die_offset and maybe_queue_comp_unit, it won't enqueue the target
CU, because it will see the CU is already expanded.
This assumes that if a CU is dwarf2_fetch_die_type_sect_off's target CU,
it will have previously been expanded. I think it is the case, but I
can't be 100% sure. If that's not true, the assertions added in the
following patch will catch it, and it means we'll have to re-think a bit
more how things work (it wouldn't be well handled at all today anyway).
This fixes something else in maybe_queue_comp_unit that looks wrong.
Imagine the DIEs of a CU are loaded in memory, but that CU is not
expanded. In that case, maybe_queue_comp_unit will use this early
return:
/* If the compilation unit is already loaded, just mark it as
used. */
dwarf2_cu *cu = per_objfile->get_cu (per_cu);
if (cu != nullptr)
{
cu->last_used = 0;
return 0;
}
... so the CU won't be queued for expansion. Whether the DIEs of a CU
are loaded in memory and whether that CU is expanded are two orthogonal
things, but that function appears to mix them. So, move the queuing
above that check / early return, so that if the CU's DIEs are loaded in
memory but the CU is not expanded yet, it gets enqueued.
I tried to improve maybe_queue_comp_unit's documentation to clarify what
the return value means. By clarifying this, I noticed that two callers
(follow_die_offset and follow_die_sig_1) access the CU's DIEs after
calling maybe_queue_comp_unit, only relying on maybe_queue_comp_unit's
return value to tell whether DIEs need to be loaded first or not. As
explained in the new comment, this is problematic:
maybe_queue_comp_unit's return value doesn't tell whether DIEs are
currently loaded, it means whether maybe_queue_comp_unit requires the
caller to load them. If the CU is already expanded but the DIEs to have
been freed, maybe_queue_comp_unit returns 0, meaning "I don't need you
to load the DIEs". So if these two functions (follow_die_offset and
follow_die_sig_1) need to access the DIEs in any case, for their own
usage, they should make sure to load them if they are not loaded
already. I therefore added an extra check to the condition they use,
making it so they will always load the DIEs if they aren't already.
From what I found, other callers don't care for the CU's DIEs, they call
maybe_queue_comp_unit to ensure the CU gets expanded eventually, but
don't care for it after that.
gdb/ChangeLog:
PR gdb/26828
* dwarf2/read.c (maybe_queue_comp_unit): Check if CU is expanded
to decide whether or not to enqueue it for expansion.
(follow_die_offset, follow_die_sig_1): Ensure we load the DIEs
after calling maybe_queue_comp_unit.
Change-Id: Id98c6b60669f4b4b21b9be16d0518fc62bdf686a
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I noticed that linux_nat_filter_event returns a value, but its caller
doesn't use it. This has been since 9c02b52532ac ("linux-nat.c: better
starvation avoidance, handle non-stop mode too"). Before that commit,
the return value was used to tell the caller whether to continue
processing that event or not. But since then, the model is that we pull
all events from the kernel and linux_nat_filter_event just saves the
status to the lwp_info structure if it thinks it's relevant. And the
caller, linux_nat_wait_1, selects a status at random amongst the threads
with a pending status. So essentially, the return value of
linux_nat_filter_event does not have a reason to be anymore. Change it
so it returns void.
gdb/ChangeLog:
* linux-nat.c (linux_nat_filter_event): Return void.
Change-Id: I35662868910f5122772ed92a512adfbf4da12d87
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While looking at Andrew's recent target sections series, I saw that
target_bfd_reopen took a "bfd *", leading to a call to new_reference.
However, because the only caller of target_bfd_reopen is already using
gdb_bfd_ref_ptr, this code can be simplified and the explicit call to
new_reference can be removed.
gdb/ChangeLog
2021-02-22 Tom Tromey <tromey@adacore.com>
* solib-svr4.c (enable_break): Update.
* bfd-target.c (class target_bfd) <target_bfd>: Change parameter
type.
(target_bfd_reopen): Change parameter type.
* bfd-target.h (target_bfd_reopen): Change parameter type.
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Unlike the previous patch, I don't propose that we take this patch into
gdb-10-branch.
This patch adds two asserts, prompted by investigating and fixing the
bug fixed by the previous patch.
The assert in find_thread_ptid would have caught the original issue
before the segfault (I think it's slightly more use friendly).
The assert in add_thread_silent would have made it clear that the
solution proposed in [1] isn't the right one. The solution ended up
passing nullptr as a target to add_thread. We don't want that, because
add_thread_silent uses it to look up the inferior to which to add the
thread. If the target is nullptr, we could find an inferior with the
same pid, but belonging to an unrelated target. So we always want a
non-nullptr target in add_thread_silent.
gdb/ChangeLog:
* thread.c (add_thread_silent): Add assert.
(find_thread_ptid): Add assert.
[1] https://sourceware.org/pipermail/gdb-patches/2021-February/176202.html
Change-Id: Ie593ee45c5eb02235e8e9fbcda612d48ce883852
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Since this is a GDB 9 -> 10 regression, I would like to push it to
gdb-10-branch.
This is a follow-up to:
https://sourceware.org/pipermail/gdb-patches/2021-February/176202.html
This patch fixes a segfault seen when attaching to a process on Solaris.
The steps leading to the segfault are:
- procfs_target::attach calls do_attach, at this point the inferior's
process slot in the target stack is empty.
- do_attach adds a thread with `add_thread (&the_procfs_target, ptid)`
- in add_thread_silent, the passed target (&the_procfs_target) is
passed to find_inferior_ptid
- find_inferior_ptid returns nullptr, as there is no inferior with this
ptid that has &the_procfs_target as its process target
- the nullptr `inf` is passed to find_thread_ptid, which dereferences
it, causing a segfault
- back in procfs_target::attach, after do_attach, we push the
the_procfs_target on the inferior's target stack, although we never
reach this because the segfault happens before.
To fix this, I think we need to do the same as is done in
inf_ptrace_target::attach: push the target early and unpush it in case
the attach fails (and keep it if the attach succeeds).
Implement it by moving target_unpush_up to target.h, so it can be
re-used here. Make procfs_target::attach use it. Note that just like
is mentioned in inf_ptrace_target::attach, we should push the target
before calling target_pid_to_str, so that calling target_pid_to_str ends
up in procfs_target::pid_to_str.
Tested by trying to attach on a process on gcc211 on the gcc compile
farm.
gdb/ChangeLog:
PR gdb/27435
* inf-ptrace.c (struct target_unpusher): Move to target.h.
(target_unpush_up): Likewise.
* procfs.c (procfs_target::attach): Push target early. Use
target_unpush_up to unpush target in case of error.
* target.h (struct target_unpusher): Move here.
(target_unpush_up): Likewise.
Change-Id: I88aff8b20204e1ca1d792e27ac6bc34fc1aa0d52
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On Fedora rawhide, after updating to glibc-2.33, I'm seeing the
following build failure:
CXX nat/amd64-linux-siginfo.o
In file included from /usr/include/bits/sigstksz.h:24,
from /usr/include/signal.h:315,
from ../gnulib/import/signal.h:52,
from /ironwood1/sourceware-git/rawhide-gnulib/bld/../../worktree-gnulib/gdbserver/../gdb/nat/amd64-linux-siginfo.c:20:
../gnulib/import/unistd.h:663:3: error: #error "Please include config.h first."
663 | #error "Please include config.h first."
| ^~~~~
glibc-2.33 has changed signal.h to now include <bits/sigstksz.h> which,
in turn, includes <unistd.h>. For a gdb build, this causes the gnulib
version of unistd.h to be pulled in first. The build failure shown
above happens because gnulib's config.h has not been included before
the include of <signal.h>.
The fix is simple - we just rearrange the order of the header file
includes to make sure that gdbsupport/commondefs.h is included before
attempting to include signal.h. Note that gdbsupport/commondefs.h
includes <gnulib/config.h>.
Build and regression tested on Fedora 33. On Fedora rawhide, GDB
builds again.
gdb/ChangeLog:
* nat/amd64-linux-siginfo.c: Include "gdbsupport/common-defs.h"
(which in turn includes <gnulib/config.h>) before include
of <signal.h>.
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