Since we converted gdbarch_make_corefile_notes to returning a
gdb::unique_xmalloc_ptr, I figured it would make sense to converted
target_ops::make_corefile_notes as well.
The only implementation of that is in procfs.c, and it should ideally be
re-written as a gdbarch method (see comment in write_gcore_file_1), but
in the mean time I guess it doesn't hurt to throw some unique pointer at
it.
I tested that it builds on Solaris 11 (gcc compile farm machine gcc211),
but I am not able to test it, because I can't get GDB to start a
process (I'll look at that separately).
gdb/ChangeLog:
* target.h (struct target_ops) <make_corefile_notes>:
Change return type to unique pointer.
* target.c (dummy_make_corefile_notes): Likewise.
* exec.c (struct exec_target) <make_corefile_notes>:
Likewise.
(exec_target::make_corefile_notes): Likewise.
* procfs.c (class procfs_target) <make_corefile_notes>:
Likewise.
(procfs_do_thread_registers): Adjust to unique pointer.
(struct procfs_corefile_thread_data): Add constructor.
<note_data>: Change type to unique pointer.
(procfs_corefile_thread_callback): Adjust to unique pointer.
(procfs_target::make_corefile_notes): Change return type to
unique pointer.
* target-delegates.c: Re-generate.
* gcore.c (write_gcore_file_1): Adjust.
* target-debug.h (target_debug_print_gdb_unique_xmalloc_ptr_char):
New.
Change-Id: I768fb17ac0f7adc67d2fe95e952c784fe0ac37ab
Debugging with "maintenance set target-async off" on Linux has been
broken since 5b6d1e4fa4 ("Multi-target support").
The issue is easy to reproduce:
$ ./gdb -q --data-directory=data-directory -nx ./test
Reading symbols from ./test...
(gdb) maintenance set target-async off
(gdb) start
Temporary breakpoint 1 at 0x1151: file test.c, line 5.
Starting program: /home/simark/build/binutils-gdb/gdb/test
... and it hangs there.
The difference between pre-5b6d1e4fa4f and 5b6d1e4fa4 is that
fetch_inferior_event now calls target_wait with TARGET_WNOHANG for
non-async-capable targets, whereas it didn't before.
For non-async-capable targets, this is how it's expected to work when
resuming execution:
1. we call resume
2. the infrun async handler is marked in prepare_to_wait, to immediately
wake up the event loop when we get back to it
3. fetch_inferior_event calls the target's wait method without
TARGET_WNOHANG, effectively blocking until the target has something
to report
However, since we call the target's wait method with TARGET_WNOHANG,
this happens:
1. we call resume
2. the infrun async handler is marked in prepare_to_wait, to immediately
wake up the event loop when we get back to it
3. fetch_inferior_event calls the target's wait method with
TARGET_WNOHANG, the target has nothing to report yet
4. we go back to blocking on the event loop
5. SIGCHLD finally arrives, but the event loop is not woken up, because
we are not in async mode. Normally, we should have been stuck in
waitpid the SIGCHLD would have unblocked us.
We end up in this situation because these two necessary conditions are
met:
1. GDB uses the TARGET_WNOHANG option with a target that can't do async.
I don't think this makes sense. I mean, it's technically possible,
the doc for TARGET_WNOHANG is:
/* Return immediately if there's no event already queued. If this
options is not requested, target_wait blocks waiting for an
event. */
TARGET_WNOHANG = 1,
... which isn't in itself necessarily incompatible with synchronous
targets. It could be possible for a target to support non-blocking
polls, while not having a way to asynchronously wake up the event
loop, which is also necessary to support async. But as of today,
we don't expect GDB and sync targets to work this way.
2. The linux-nat target, even in the mode where it emulates a
synchronous target (with "maintenance set target-async off") respects
TARGET_WNOHANG. Other non-async targets, such as windows_nat_target,
simply don't check / support TARGET_WNOHANG, so their wait method is
always blocking.
Fix the first issue by avoiding using TARGET_WNOHANG on non-async
targets, in do_target_wait_1. Add an assert in target_wait to verify it
doesn't happen.
The new test gdb.base/maint-target-async-off.exp is a simple test that
just tries running to main and then to the end of the program, with
"maintenance set target-async off".
gdb/ChangeLog:
PR gdb/26642
* infrun.c (do_target_wait_1): Clear TARGET_WNOHANG if the
target can't do async.
* target.c (target_wait): Assert that we don't pass
TARGET_WNOHANG to a target that can't async.
gdb/testsuite/ChangeLog:
PR gdb/26642
* gdb.base/maint-target-async-off.c: New test.
* gdb.base/maint-target-async-off.exp: New test.
Change-Id: I69ad3a14598863d21338a8c4e78700a58ce7ad86
Because target_section_table only holds a vector, and because it is
used in an "open" way, this patch makes it just be an alias for the
std::vector specialization. This makes the code less wordy. If we do
ever want to add more specialized behavior to this type, it's simple
enough to convert it back to a struct with the few needed methods
implied by this change.
gdb/ChangeLog
2020-10-12 Tom Tromey <tom@tromey.com>
* target.h (struct target_ops) <get_section_table>: Update.
(target_get_section_table): Update.
* target.c (target_get_section_table, target_section_by_addr)
(memory_xfer_partial_1): Update.
* target-section.h (target_section_table): Now an alias.
* target-delegates.c: Rebuild.
* target-debug.h (target_debug_print_target_section_table_p):
Rename from target_debug_print_struct_target_section_table_p.
* symfile.c (build_section_addr_info_from_section_table): Update.
* solib.c (solib_map_sections, solib_contains_address_p): Update.
* solib-svr4.c (scan_dyntag): Update.
* solib-dsbt.c (scan_dyntag): Update.
* remote.c (remote_target::remote_xfer_live_readonly_partial):
Update.
* record-full.c (record_full_core_target::xfer_partial): Update.
* progspace.h (struct program_space) <target_sections>: Update.
* exec.h (print_section_info): Update.
* exec.c (exec_target::close, build_section_table)
(add_target_sections, add_target_sections_of_objfile)
(remove_target_sections, exec_on_vfork)
(section_table_available_memory)
(section_table_xfer_memory_partial)
(exec_target::get_section_table, exec_target::xfer_partial)
(print_section_info, set_section_command)
(exec_set_section_address, exec_target::has_memory): Update.
* corelow.c (core_target::build_file_mappings)
(core_target::xfer_partial, core_target::info_proc_mappings)
(core_target::info_proc_mappings): Update.
* bfd-target.c (class target_bfd): Update
This changes target_section_table to wrap a std::vector. This
simplifies some code, and also enables the simplifications coming in
the subsequent patches.
Note that for solib, I chose to have it use a pointer to a
target_section_table. This is more convoluted than would be ideal,
but I didn't want to convert solib to new/delete as a prerequisite for
this series.
gdb/ChangeLog
2020-10-12 Tom Tromey <tom@tromey.com>
* target.c (target_section_by_addr, memory_xfer_partial_1):
Update.
* target-section.h (struct target_section_table): Use
std::vector.
* symfile.h (build_section_addr_info_from_section_table): Take a
target_section_table.
* symfile.c (build_section_addr_info_from_section_table): Take a
target_section_table.
* solist.h (struct so_list) <sections>: Change type.
<sections_end>: Remove.
* solib.c (solib_map_sections, clear_so, solib_read_symbols)
(solib_contains_address_p): Update.
* solib-svr4.c (scan_dyntag): Update.
* solib-dsbt.c (scan_dyntag): Update.
* remote.c (remote_target::remote_xfer_live_readonly_partial):
Update.
* record-full.c (record_full_core_start, record_full_core_end):
Remove.
(record_full_core_sections): New global.
(record_full_core_open_1, record_full_core_target::xfer_partial):
Update.
* exec.h (build_section_table, section_table_xfer_memory_partial)
(add_target_sections): Take a target_section_table.
* exec.c (exec_file_attach, clear_section_table): Update.
(resize_section_table): Remove.
(build_section_table, add_target_sections): Take a
target_section_table.
(add_target_sections_of_objfile, remove_target_sections)
(exec_on_vfork): Update.
(section_table_available_memory): Take a target_section_table.
(section_table_read_available_memory): Update.
(section_table_xfer_memory_partial): Take a target_section_table.
(print_section_info, set_section_command)
(exec_set_section_address, exec_target::has_memory): Update.
* corelow.c (class core_target) <m_core_section_table,
m_core_file_mappings>: Remove braces.
<~core_target>: Remove.
(core_target::core_target): Update.
(core_target::~core_target): Remove.
(core_target::build_file_mappings)
(core_target::xfer_memory_via_mappings)
(core_target::xfer_partial, core_target::info_proc_mappings):
Update.
* bfd-target.c (target_bfd::xfer_partial): Update.
(target_bfd::target_bfd): Update.
(target_bfd::~target_bfd): Remove.
This moves the simple_search_memory function to a new file,
gdbsupport/search.cc. The API is slightly changed to make it more
general. This generality is useful for wiring it to gdbserver, and
also for unit testing.
gdb/ChangeLog
2020-10-07 Tom Tromey <tromey@adacore.com>
* target.h (simple_search_memory): Don't declare.
* target.c (simple_search_memory): Move to gdbsupport.
(default_search_memory): Update.
* remote.c (remote_target::search_memory): Update.
gdbsupport/ChangeLog
2020-10-07 Tom Tromey <tromey@adacore.com>
* Makefile.in: Rebuild.
* Makefile.am (libgdbsupport_a_SOURCES): Add search.cc.
* search.h: New file.
* search.cc: New file.
This changes target_can_execute_reverse from an object-like macro to
an inline function.
gdb/ChangeLog
2020-09-28 Tom Tromey <tom@tromey.com>
* mi/mi-main.c (exec_reverse_continue)
(mi_cmd_list_target_features): Update.
* infrun.c (set_exec_direction_func): Update.
* target.c (default_execution_direction): Update.
* reverse.c (exec_reverse_once): Update.
* target.h (target_can_execute_reverse): Now a function.
Consider the following program:
- - - mkmmapcore.c - - -
static char *buf;
int
main (int argc, char **argv)
{
buf = mmap (NULL, 8192, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
abort ();
}
- - - end mkmmapcore.c - - -
Compile it like this:
gcc -g -o mkmmapcore mkmmapcore.c
Now let's run it from GDB. I've already placed a breakpoint on the
line with the abort() call and have run to that breakpoint.
Breakpoint 1, main (argc=1, argv=0x7fffffffd678) at mkmmapcore.c:11
11 abort ();
(gdb) x/x buf
0x7ffff7fcb000: 0x00000000
Note that we can examine the memory allocated via the call to mmap().
Now let's try debugging a core file created by running this program.
Depending on your system, in order to make a core file, you may have to
run the following as root (or using sudo):
echo core > /proc/sys/kernel/core_pattern
It may also be necessary to do:
ulimit -c unlimited
I'm using Fedora 31. YMMV if you're using one of the BSDs or some other
(non-Linux) system.
This is what things look like when we debug the core file:
[kev@f31-1 tmp]$ gdb -q ./mkmmapcore core.304767
Reading symbols from ./mkmmapcore...
[New LWP 304767]
Core was generated by `/tmp/mkmmapcore'.
Program terminated with signal SIGABRT, Aborted.
#0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
50 return ret;
(gdb) x/x buf
0x7ffff7fcb000: Cannot access memory at address 0x7ffff7fcb000
Note that we can no longer access the memory region allocated by mmap().
Back in 2007, a hack for GDB was added to _bfd_elf_make_section_from_phdr()
in bfd/elf.c:
/* Hack for gdb. Segments that have not been modified do
not have their contents written to a core file, on the
assumption that a debugger can find the contents in the
executable. We flag this case by setting the fake
section size to zero. Note that "real" bss sections will
always have their contents dumped to the core file. */
if (bfd_get_format (abfd) == bfd_core)
newsect->size = 0;
You can find the entire patch plus links to other discussion starting
here:
https://sourceware.org/ml/binutils/2007-08/msg00047.html
This hack sets the size of certain BFD sections to 0, which
effectively causes GDB to ignore them. I think it's likely that the
bug described above existed even before this hack was added, but I
have no easy way to test this now.
The output from objdump -h shows the result of this hack:
25 load13 00000000 00007ffff7fcb000 0000000000000000 00013000 2**12
ALLOC
(The first field, after load13, shows the size of 0.)
Once the hack is removed, the output from objdump -h shows the correct
size:
25 load13 00002000 00007ffff7fcb000 0000000000000000 00013000 2**12
ALLOC
(This is a digression, but I think it's good that objdump will now show
the correct size.)
If we remove the hack from bfd/elf.c, but do nothing to GDB, we'll
see the following regression:
FAIL: gdb.base/corefile.exp: print coremaker_ro
The reason for this is that all sections which have the BFD flag
SEC_ALLOC set, but for which SEC_HAS_CONTENTS is not set no longer
have zero size. Some of these sections have data that can (and should)
be read from the executable. (Sections for which SEC_HAS_CONTENTS
is set should be read from the core file; sections which do not have
this flag set need to either be read from the executable or, failing
that, from the core file using whatever BFD decides is the best value
to present to the user - it uses zeros.)
At present, due to the way that the target strata are traversed when
attempting to access memory, the non-SEC_HAS_CONTENTS sections will be
read as zeroes from the process_stratum (which in this case is the
core file stratum) without first checking the file stratum, which is
where the data might actually be found.
What we should be doing is this:
- Attempt to access core file data for SEC_HAS_CONTENTS sections.
- Attempt to access executable file data if the above fails.
- Attempt to access core file data for non SEC_HAS_CONTENTS sections, if
both of the above fail.
This corresponds to the analysis of Daniel Jacobowitz back in 2007
when the hack was added to BFD:
https://sourceware.org/legacy-ml/binutils/2007-08/msg00045.html
The difference, observed by Pedro in his review of my v1 patches, is
that I'm using "the section flags as proxy for the p_filesz/p_memsz
checks."
gdb/ChangeLog:
PR corefiles/25631
* corelow.c (core_target:xfer_partial): Revise
TARGET_OBJECT_MEMORY case to consider non-SEC_HAS_CONTENTS
case after first checking the stratum beneath the core
target.
(has_all_memory): Return true.
* target.c (raw_memory_xfer_partial): Revise comment
regarding use of has_all_memory.
This patch is motivated by the need to be able to select sections
that section_table_xfer_memory_partial should consider for memory
transfers. I'll use this facility in the next patch in this series.
section_table_xfer_memory_partial() can currently be passed a section
name which may be used to make name-based selections. This is similar
to what I want to do, except that I want to be able to consider
section flags instead of the name.
I'm replacing the section name parameter with a predicate that,
when passed a pointer to a target_section struct, will return
true if that section should be further considered, or false which
indicates that it shouldn't.
I've converted the one existing use where a non-NULL section
name is passed to section_table_xfer_memory_partial(). Instead
of passing the section name, it now looks like this:
auto match_cb = [=] (const struct target_section *s)
{
return (strcmp (section_name, s->the_bfd_section->name) == 0);
};
return section_table_xfer_memory_partial (readbuf, writebuf,
memaddr, len, xfered_len,
table->sections,
table->sections_end,
match_cb);
The other callers all passed NULL; they've been simplified somewhat
in that they no longer need to pass NULL.
gdb/ChangeLog:
* exec.h (section_table_xfer_memory): Revise declaration,
replacing section name parameter with an optional callback
predicate.
* exec.c (section_table_xfer_memory): Likewise.
* bfd-target.c, exec.c, target.c, corelow.c: Adjust all callers
of section_table_xfer_memory.
We were checking the thr->executing of an exited thread.
gdb/ChangeLog:
PR gdb/26199
* target.c (target_pass_ctrlc): Look at the inferior's non-exited
threads, not all threads.
gdb/ChangeLog:
2020-06-18 Pedro Alves <palves@redhat.com>
* target.c (generic_mourn_inferior): Use switch_to_no_thread
instead of writing to inferior_ptid.
This simplifies the target_read_string API a bit.
Note that some code was using safe_strerror on the error codes
returned by target_read_string. It seems to me that this is incorrect
(if it was ever correct, it must have been quite a long time ago).
gdb/ChangeLog
2020-06-15 Tom Tromey <tromey@adacore.com>
* windows-nat.c (windows_nat::handle_output_debug_string):
Update.
(windows_nat::handle_ms_vc_exception): Update.
* target.h (target_read_string): Change API.
* target.c (target_read_string): Change API.
* solib-svr4.c (open_symbol_file_object, svr4_read_so_list):
Update.
* solib-frv.c (frv_current_sos): Update.
* solib-dsbt.c (dsbt_current_sos): Update.
* solib-darwin.c (darwin_current_sos): Update.
* linux-thread-db.c (inferior_has_bug): Update.
* expprint.c (print_subexp_standard): Update.
* ada-lang.c (ada_main_name, ada_tag_name_from_tsd)
(ada_exception_message_1): Update.
This basically makes target_fileio_open_1 extern, renamed to
target_fileio_open, and eliminates the current
target_fileio_open_warn_if_slow and target_fileio_open.
A following parameter will want to change gdb_bfd_iovec_fileio_open,
the only caller of target_fileio_open_warn_if_slow, to pass down
"warn_if_slow" true/false from the caller, instead of hardcoding
"warn_if_slow" true.
gdb/ChangeLog:
2020-05-19 Pedro Alves <palves@redhat.com>
* gdb_bfd.c (gdb_bfd_iovec_fileio_open): Adjust.
* target.c (target_fileio_open_1): Rename to target_fileio_open
and make extern. Use bool.
(target_fileio_open, target_fileio_open_warn_if_slow): Delete.
(target_fileio_read_alloc_1): Adjust.
* target.h (target_fileio_open): Add 'warn_if_slow' parameter.
(target_fileio_open_warn_if_slow): Delete declaration.
I looked at all the calls to add_prefix_cmd, and replaced them with
calls to add_basic_prefix_cmd or add_show_prefix_cmd when appropriate.
This makes gdb's command language a bit more regular. I don't think
there's a significant downside.
Note that this patch removes a couple of tests. The removed ones are
completely redundant.
gdb/ChangeLog
2020-05-03 Tom Tromey <tom@tromey.com>
* breakpoint.c (catch_command, tcatch_command): Remove.
(_initialize_breakpoint): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
(set_breakpoint_cmd, show_breakpoint_cmd): Remove
* utils.c (set_internal_problem_cmd, show_internal_problem_cmd):
Remove.
(add_internal_problem_command): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* mips-tdep.c (set_mipsfpu_command): Remove.
(_initialize_mips_tdep): Use add_basic_prefix_cmd.
* dwarf2/index-cache.c (set_index_cache_command): Remove.
(_initialize_index_cache): Use add_basic_prefix_cmd.
* memattr.c (dummy_cmd): Remove.
(_initialize_mem): Use add_basic_prefix_cmd, add_show_prefix_cmd.
* tui/tui-win.c (set_tui_cmd, show_tui_cmd): Remove.
(_initialize_tui_win): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* cli/cli-logging.c (set_logging_command): Remove.
(_initialize_cli_logging): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
(show_logging_command): Remove.
* target.c (target_command): Remove.
(add_target): Use add_basic_prefix_cmd.
gdb/testsuite/ChangeLog
2020-05-03 Tom Tromey <tom@tromey.com>
* gdb.base/sepdebug.exp: Remove "catch" test.
* gdb.base/break.exp: Remove "catch" test.
* gdb.base/default.exp: Update expected output.
Define a predicate function that returns true if there exists an
inferior with a non-stop target.
gdb/ChangeLog:
2020-04-01 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* target.h (exists_non_stop_target): New function declaration.
* target.c (exists_non_stop_target): New function.
This commit extends the CLI a bit for multi-target, in three ways.
#1 - New "info connections" command.
This is a new command that lists the open connections (process_stratum
targets). For example, if you're debugging two remote connections, a
couple local/native processes, and a core dump, all at the same time,
you might see something like this:
(gdb) info connections
Num What Description
1 remote 192.168.0.1:9999 Remote serial target in gdb-specific protocol
2 remote 192.168.0.2:9998 Remote serial target in gdb-specific protocol
* 3 native Native process
4 core Local core dump file
#2 - New "info inferiors" "Connection" column
You'll also see a new matching "Connection" column in "info
inferiors", showing you which connection an inferior is bound to:
(gdb) info inferiors
Num Description Connection Executable
1 process 18526 1 (remote 192.168.0.1:9999) target:/tmp/a.out
2 process 18531 2 (remote 192.168.0.2:9998) target:/tmp/a.out
3 process 19115 3 (native) /tmp/prog1
4 process 6286 4 (core) myprogram
* 5 process 19122 3 (native) /bin/hello
#3 - Makes "add-inferior" show the inferior's target connection
"add-inferior" now shows you the connection you've just bound the
inferior to, which is the current process_stratum target:
(gdb) add-inferior
[New inferior 2]
Added inferior 2 on connection 1 (extended-remote localhost:2346)
gdb/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* Makefile.in (COMMON_SFILES): Add target-connection.c.
* inferior.c (uiout_field_connection): New function.
(print_inferior): Add new "connection-id" column.
(add_inferior_command): Show connection number/string of added
inferior.
* process-stratum-target.h
(process_stratum_target::connection_string): New virtual method.
(process_stratum_target::connection_number): New field.
* remote.c (remote_target::connection_string): New override.
* target-connection.c: New file.
* target-connection.h: New file.
* target.c (decref_target): Remove process_stratum targets from
the connection list.
(target_stack::push): Add process_stratum targets to the
connection list.
gdb/testsuite/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* gdb.base/kill-detach-inferiors-cmd.exp: Adjust expected output
of "add-inferior".
* gdb.base/quit-live.exp: Likewise.
* gdb.base/remote-exec-file.exp: Likewise.
* gdb.guile/scm-progspace.exp: Likewise.
* gdb.linespec/linespec.exp: Likewise.
* gdb.mi/new-ui-mi-sync.exp: Likewise.
* gdb.mi/user-selected-context-sync.exp: Likewise.
* gdb.multi/multi-target.exp (setup): Add "info connection" and
"info inferiors" tests.
* gdb.multi/remove-inferiors.exp: Adjust expected output of
"add-inferior".
* gdb.multi/watchpoint-multi.exp: Likewise.
* gdb.python/py-inferior.exp: Likewise.
* gdb.server/extended-remote-restart.exp: Likewise.
* gdb.threads/fork-plus-threads.exp: Adjust expected output of
"info inferiors".
* gdb.threads/forking-threads-plus-breakpoint.exp: Likewise.
* gdb.trace/report.exp: Likewise.
This commit adds multi-target support to GDB. What this means is that
with this commit, GDB can now be connected to different targets at the
same time. E.g., you can debug a live native process and a core dump
at the same time, connect to multiple gdbservers, etc.
Actually, the word "target" is overloaded in gdb. We already have a
target stack, with pushes several target_ops instances on top of one
another. We also have "info target" already, which means something
completely different to what this patch does.
So from here on, I'll be using the "target connections" term, to mean
an open process_stratum target, pushed on a target stack. This patch
makes gdb have multiple target stacks, and multiple process_stratum
targets open simultaneously. The user-visible changes / commands will
also use this terminology, but of course it's all open to debate.
User-interface-wise, not that much changes. The main difference is
that each inferior may have its own target connection.
A target connection (e.g., a target extended-remote connection) may
support debugging multiple processes, just as before.
Say you're debugging against gdbserver in extended-remote mode, and
you do "add-inferior" to prepare to spawn a new process, like:
(gdb) target extended-remote :9999
...
(gdb) start
...
(gdb) add-inferior
Added inferior 2
(gdb) inferior 2
[Switching to inferior 2 [<null>] (<noexec>)]
(gdb) file a.out
...
(gdb) start
...
At this point, you have two inferiors connected to the same gdbserver.
With this commit, GDB will maintain a target stack per inferior,
instead of a global target stack.
To preserve the behavior above, by default, "add-inferior" makes the
new inferior inherit a copy of the target stack of the current
inferior. Same across a fork - the child inherits a copy of the
target stack of the parent. While the target stacks are copied, the
targets themselves are not. Instead, target_ops is made a
refcounted_object, which means that target_ops instances are
refcounted, which each inferior counting for a reference.
What if you want to create an inferior and connect it to some _other_
target? For that, this commit introduces a new "add-inferior
-no-connection" option that makes the new inferior not share the
current inferior's target. So you could do:
(gdb) target extended-remote :9999
Remote debugging using :9999
...
(gdb) add-inferior -no-connection
[New inferior 2]
Added inferior 2
(gdb) inferior 2
[Switching to inferior 2 [<null>] (<noexec>)]
(gdb) info inferiors
Num Description Executable
1 process 18401 target:/home/pedro/tmp/main
* 2 <null>
(gdb) tar extended-remote :10000
Remote debugging using :10000
...
(gdb) info inferiors
Num Description Executable
1 process 18401 target:/home/pedro/tmp/main
* 2 process 18450 target:/home/pedro/tmp/main
(gdb)
A following patch will extended "info inferiors" to include a column
indicating which connection an inferior is bound to, along with a
couple other UI tweaks.
Other than that, debugging is the same as before. Users interact with
inferiors and threads as before. The only difference is that
inferiors may be bound to processes running in different machines.
That's pretty much all there is to it in terms of noticeable UI
changes.
On to implementation.
Since we can be connected to different systems at the same time, a
ptid_t is no longer a unique identifier. Instead a thread can be
identified by a pair of ptid_t and 'process_stratum_target *', the
later being the instance of the process_stratum target that owns the
process/thread. Note that process_stratum_target inherits from
target_ops, and all process_stratum targets inherit from
process_stratum_target. In earlier patches, many places in gdb were
converted to refer to threads by thread_info pointer instead of
ptid_t, but there are still places in gdb where we start with a
pid/tid and need to find the corresponding inferior or thread_info
objects. So you'll see in the patch many places adding a
process_stratum_target parameter to functions that used to take only a
ptid_t.
Since each inferior has its own target stack now, we can always find
the process_stratum target for an inferior. That is done via a
inf->process_target() convenience method.
Since each inferior has its own target stack, we need to handle the
"beneath" calls when servicing target calls. The solution I settled
with is just to make sure to switch the current inferior to the
inferior you want before making a target call. Not relying on global
context is just not feasible in current GDB. Fortunately, there
aren't that many places that need to do that, because generally most
code that calls target methods already has the current context
pointing to the right inferior/thread. Note, to emphasize -- there's
no method to "switch to this target stack". Instead, you switch the
current inferior, and that implicitly switches the target stack.
In some spots, we need to iterate over all inferiors so that we reach
all target stacks.
Native targets are still singletons. There's always only a single
instance of such targets.
Remote targets however, we'll have one instance per remote connection.
The exec target is still a singleton. There's only one instance. I
did not see the point of instanciating more than one exec_target
object.
After vfork, we need to make sure to push the exec target on the new
inferior. See exec_on_vfork.
For type safety, functions that need a {target, ptid} pair to identify
a thread, take a process_stratum_target pointer for target parameter
instead of target_ops *. Some shared code in gdb/nat/ also need to
gain a target pointer parameter. This poses an issue, since gdbserver
doesn't have process_stratum_target, only target_ops. To fix this,
this commit renames gdbserver's target_ops to process_stratum_target.
I think this makes sense. There's no concept of target stack in
gdbserver, and gdbserver's target_ops really implements a
process_stratum-like target.
The thread and inferior iterator functions also gain
process_stratum_target parameters. These are used to be able to
iterate over threads and inferiors of a given target. Following usual
conventions, if the target pointer is null, then we iterate over
threads and inferiors of all targets.
I tried converting "add-inferior" to the gdb::option framework, as a
preparatory patch, but that stumbled on the fact that gdb::option does
not support file options yet, for "add-inferior -exec". I have a WIP
patchset that adds that, but it's not a trivial patch, mainly due to
need to integrate readline's filename completion, so I deferred that
to some other time.
In infrun.c/infcmd.c, the main change is that we need to poll events
out of all targets. See do_target_wait. Right after collecting an
event, we switch the current inferior to an inferior bound to the
target that reported the event, so that target methods can be used
while handling the event. This makes most of the code transparent to
multi-targets. See fetch_inferior_event.
infrun.c:stop_all_threads is interesting -- in this function we need
to stop all threads of all targets. What the function does is send an
asynchronous stop request to all threads, and then synchronously waits
for events, with target_wait, rinse repeat, until all it finds are
stopped threads. Now that we have multiple targets, it's not
efficient to synchronously block in target_wait waiting for events out
of one target. Instead, we implement a mini event loop, with
interruptible_select, select'ing on one file descriptor per target.
For this to work, we need to be able to ask the target for a waitable
file descriptor. Such file descriptors already exist, they are the
descriptors registered in the main event loop with add_file_handler,
inside the target_async implementations. This commit adds a new
target_async_wait_fd target method that just returns the file
descriptor in question. See wait_one / stop_all_threads in infrun.c.
The 'threads_executing' global is made a per-target variable. Since
it is only relevant to process_stratum_target targets, this is where
it is put, instead of in target_ops.
You'll notice that remote.c includes some FIXME notes. These refer to
the fact that the global arrays that hold data for the remote packets
supported are still globals. For example, if we connect to two
different servers/stubs, then each might support different remote
protocol features. They might even be different architectures, like
e.g., one ARM baremetal stub, and a x86 gdbserver, to debug a
host/controller scenario as a single program. That isn't going to
work correctly today, because of said globals. I'm leaving fixing
that for another pass, since it does not appear to be trivial, and I'd
rather land the base work first. It's already useful to be able to
debug multiple instances of the same server (e.g., a distributed
cluster, where you have full control over the servers installed), so I
think as is it's already reasonable incremental progress.
Current limitations:
- You can only resume more that one target at the same time if all
targets support asynchronous debugging, and support non-stop mode.
It should be possible to support mixed all-stop + non-stop
backends, but that is left for another time. This means that
currently in order to do multi-target with gdbserver you need to
issue "maint set target-non-stop on". I would like to make that
mode be the default, but we're not there yet. Note that I'm
talking about how the target backend works, only. User-visible
all-stop mode works just fine.
- As explained above, connecting to different remote servers at the
same time is likely to produce bad results if they don't support the
exact set of RSP features.
FreeBSD updates courtesy of John Baldwin.
gdb/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
John Baldwin <jhb@FreeBSD.org>
* aarch64-linux-nat.c
(aarch64_linux_nat_target::thread_architecture): Adjust.
* ada-tasks.c (print_ada_task_info): Adjust find_thread_ptid call.
(task_command_1): Likewise.
* aix-thread.c (sync_threadlists, aix_thread_target::resume)
(aix_thread_target::wait, aix_thread_target::fetch_registers)
(aix_thread_target::store_registers)
(aix_thread_target::thread_alive): Adjust.
* amd64-fbsd-tdep.c: Include "inferior.h".
(amd64fbsd_get_thread_local_address): Pass down target.
* amd64-linux-nat.c (ps_get_thread_area): Use ps_prochandle
thread's gdbarch instead of target_gdbarch.
* break-catch-sig.c (signal_catchpoint_print_it): Adjust call to
get_last_target_status.
* break-catch-syscall.c (print_it_catch_syscall): Likewise.
* breakpoint.c (breakpoints_should_be_inserted_now): Consider all
inferiors.
(update_inserted_breakpoint_locations): Skip if inferiors with no
execution.
(update_global_location_list): When handling moribund locations,
find representative inferior for location's pspace, and use thread
count of its process_stratum target.
* bsd-kvm.c (bsd_kvm_target_open): Pass target down.
* bsd-uthread.c (bsd_uthread_target::wait): Use
as_process_stratum_target and adjust thread_change_ptid and
add_thread calls.
(bsd_uthread_target::update_thread_list): Use
as_process_stratum_target and adjust find_thread_ptid,
thread_change_ptid and add_thread calls.
* btrace.c (maint_btrace_packet_history_cmd): Adjust
find_thread_ptid call.
* corelow.c (add_to_thread_list): Adjust add_thread call.
(core_target_open): Adjust add_thread_silent and thread_count
calls.
(core_target::pid_to_str): Adjust find_inferior_ptid call.
* ctf.c (ctf_target_open): Adjust add_thread_silent call.
* event-top.c (async_disconnect): Pop targets from all inferiors.
* exec.c (add_target_sections): Push exec target on all inferiors
sharing the program space.
(remove_target_sections): Remove the exec target from all
inferiors sharing the program space.
(exec_on_vfork): New.
* exec.h (exec_on_vfork): Declare.
* fbsd-nat.c (fbsd_add_threads): Add fbsd_nat_target parameter.
Pass it down.
(fbsd_nat_target::update_thread_list): Adjust.
(fbsd_nat_target::resume): Adjust.
(fbsd_handle_debug_trap): Add fbsd_nat_target parameter. Pass it
down.
(fbsd_nat_target::wait, fbsd_nat_target::post_attach): Adjust.
* fbsd-tdep.c (fbsd_corefile_thread): Adjust
get_thread_arch_regcache call.
* fork-child.c (gdb_startup_inferior): Pass target down to
startup_inferior and set_executing.
* gdbthread.h (struct process_stratum_target): Forward declare.
(add_thread, add_thread_silent, add_thread_with_info)
(in_thread_list): Add process_stratum_target parameter.
(find_thread_ptid(inferior*, ptid_t)): New overload.
(find_thread_ptid, thread_change_ptid): Add process_stratum_target
parameter.
(all_threads()): Delete overload.
(all_threads, all_non_exited_threads): Add process_stratum_target
parameter.
(all_threads_safe): Use brace initialization.
(thread_count): Add process_stratum_target parameter.
(set_resumed, set_running, set_stop_requested, set_executing)
(threads_are_executing, finish_thread_state): Add
process_stratum_target parameter.
(switch_to_thread): Use is_current_thread.
* i386-fbsd-tdep.c: Include "inferior.h".
(i386fbsd_get_thread_local_address): Pass down target.
* i386-linux-nat.c (i386_linux_nat_target::low_resume): Adjust.
* inf-child.c (inf_child_target::maybe_unpush_target): Remove
have_inferiors check.
* inf-ptrace.c (inf_ptrace_target::create_inferior)
(inf_ptrace_target::attach): Adjust.
* infcall.c (run_inferior_call): Adjust.
* infcmd.c (run_command_1): Pass target to
scoped_finish_thread_state.
(proceed_thread_callback): Skip inferiors with no execution.
(continue_command): Rename 'all_threads' local to avoid hiding
'all_threads' function. Adjust get_last_target_status call.
(prepare_one_step): Adjust set_running call.
(signal_command): Use user_visible_resume_target. Compare thread
pointers instead of inferior_ptid.
(info_program_command): Adjust to pass down target.
(attach_command): Mark target's 'thread_executing' flag.
(stop_current_target_threads_ns): New, factored out from ...
(interrupt_target_1): ... this. Switch inferior before making
target calls.
* inferior-iter.h
(struct all_inferiors_iterator, struct all_inferiors_range)
(struct all_inferiors_safe_range)
(struct all_non_exited_inferiors_range): Filter on
process_stratum_target too. Remove explicit.
* inferior.c (inferior::inferior): Push dummy target on target
stack.
(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors):
Add process_stratum_target parameter, and pass it down.
(have_live_inferiors): Adjust.
(switch_to_inferior_and_push_target): New.
(add_inferior_command, clone_inferior_command): Handle
"-no-connection" parameter. Use
switch_to_inferior_and_push_target.
(_initialize_inferior): Mention "-no-connection" option in
the help of "add-inferior" and "clone-inferior" commands.
* inferior.h: Include "process-stratum-target.h".
(interrupt_target_1): Use bool.
(struct inferior) <push_target, unpush_target, target_is_pushed,
find_target_beneath, top_target, process_target, target_at,
m_stack>: New.
(discard_all_inferiors): Delete.
(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors)
(all_inferiors, all_non_exited_inferiors): Add
process_stratum_target parameter.
* infrun.c: Include "gdb_select.h" and <unordered_map>.
(target_last_proc_target): New global.
(follow_fork_inferior): Push target on new inferior. Pass target
to add_thread_silent. Call exec_on_vfork. Handle target's
reference count.
(follow_fork): Adjust get_last_target_status call. Also consider
target.
(follow_exec): Push target on new inferior.
(struct execution_control_state) <target>: New field.
(user_visible_resume_target): New.
(do_target_resume): Call target_async.
(resume_1): Set target's threads_executing flag. Consider resume
target.
(commit_resume_all_targets): New.
(proceed): Also consider resume target. Skip threads of inferiors
with no execution. Commit resumtion in all targets.
(start_remote): Pass current inferior to wait_for_inferior.
(infrun_thread_stop_requested): Consider target as well. Pass
thread_info pointer to clear_inline_frame_state instead of ptid.
(infrun_thread_thread_exit): Consider target as well.
(random_pending_event_thread): New inferior parameter. Use it.
(do_target_wait): Rename to ...
(do_target_wait_1): ... this. Add inferior parameter, and pass it
down.
(threads_are_resumed_pending_p, do_target_wait): New.
(prepare_for_detach): Adjust calls.
(wait_for_inferior): New inferior parameter. Handle it. Use
do_target_wait_1 instead of do_target_wait.
(fetch_inferior_event): Adjust. Switch to representative
inferior. Pass target down.
(set_last_target_status): Add process_stratum_target parameter.
Save target in global.
(get_last_target_status): Add process_stratum_target parameter and
handle it.
(nullify_last_target_wait_ptid): Clear 'target_last_proc_target'.
(context_switch): Check inferior_ptid == null_ptid before calling
inferior_thread().
(get_inferior_stop_soon): Pass down target.
(wait_one): Rename to ...
(poll_one_curr_target): ... this.
(struct wait_one_event): New.
(wait_one): New.
(stop_all_threads): Adjust.
(handle_no_resumed, handle_inferior_event): Adjust to consider the
event's target.
(switch_back_to_stepped_thread): Also consider target.
(print_stop_event): Update.
(normal_stop): Update. Also consider the resume target.
* infrun.h (wait_for_inferior): Remove declaration.
(user_visible_resume_target): New declaration.
(get_last_target_status, set_last_target_status): New
process_stratum_target parameter.
* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
process_stratum_target parameter, and use it.
(clear_inline_frame_state (thread_info*)): New.
* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
process_stratum_target parameter.
(clear_inline_frame_state (thread_info*)): Declare.
* linux-fork.c (delete_checkpoint_command): Pass target down to
find_thread_ptid.
(checkpoint_command): Adjust.
* linux-nat.c (linux_nat_target::follow_fork): Switch to thread
instead of just tweaking inferior_ptid.
(linux_nat_switch_fork): Pass target down to thread_change_ptid.
(exit_lwp): Pass target down to find_thread_ptid.
(attach_proc_task_lwp_callback): Pass target down to
add_thread/set_running/set_executing.
(linux_nat_target::attach): Pass target down to
thread_change_ptid.
(get_detach_signal): Pass target down to find_thread_ptid.
Consider last target status's target.
(linux_resume_one_lwp_throw, resume_lwp)
(linux_handle_syscall_trap, linux_handle_extended_wait, wait_lwp)
(stop_wait_callback, save_stop_reason, linux_nat_filter_event)
(linux_nat_wait_1, resume_stopped_resumed_lwps): Pass target down.
(linux_nat_target::async_wait_fd): New.
(linux_nat_stop_lwp, linux_nat_target::thread_address_space): Pass
target down.
* linux-nat.h (linux_nat_target::async_wait_fd): Declare.
* linux-tdep.c (get_thread_arch_regcache): Pass target down.
* linux-thread-db.c (struct thread_db_info::process_target): New
field.
(add_thread_db_info): Save target.
(get_thread_db_info): New process_stratum_target parameter. Also
match target.
(delete_thread_db_info): New process_stratum_target parameter.
Also match target.
(thread_from_lwp): Adjust to pass down target.
(thread_db_notice_clone): Pass down target.
(check_thread_db_callback): Pass down target.
(try_thread_db_load_1): Always push the thread_db target.
(try_thread_db_load, record_thread): Pass target down.
(thread_db_target::detach): Pass target down. Always unpush the
thread_db target.
(thread_db_target::wait, thread_db_target::mourn_inferior): Pass
target down. Always unpush the thread_db target.
(find_new_threads_callback, thread_db_find_new_threads_2)
(thread_db_target::update_thread_list): Pass target down.
(thread_db_target::pid_to_str): Pass current inferior down.
(thread_db_target::get_thread_local_address): Pass target down.
(thread_db_target::resume, maintenance_check_libthread_db): Pass
target down.
* nto-procfs.c (nto_procfs_target::update_thread_list): Adjust.
* procfs.c (procfs_target::procfs_init_inferior): Declare.
(proc_set_current_signal, do_attach, procfs_target::wait): Adjust.
(procfs_init_inferior): Rename to ...
(procfs_target::procfs_init_inferior): ... this and adjust.
(procfs_target::create_inferior, procfs_notice_thread)
(procfs_do_thread_registers): Adjust.
* ppc-fbsd-tdep.c: Include "inferior.h".
(ppcfbsd_get_thread_local_address): Pass down target.
* proc-service.c (ps_xfer_memory): Switch current inferior and
program space as well.
(get_ps_regcache): Pass target down.
* process-stratum-target.c
(process_stratum_target::thread_address_space)
(process_stratum_target::thread_architecture): Pass target down.
* process-stratum-target.h
(process_stratum_target::threads_executing): New field.
(as_process_stratum_target): New.
* ravenscar-thread.c
(ravenscar_thread_target::update_inferior_ptid): Pass target down.
(ravenscar_thread_target::wait, ravenscar_add_thread): Pass target
down.
* record-btrace.c (record_btrace_target::info_record): Adjust.
(record_btrace_target::record_method)
(record_btrace_target::record_is_replaying)
(record_btrace_target::fetch_registers)
(get_thread_current_frame_id, record_btrace_target::resume)
(record_btrace_target::wait, record_btrace_target::stop): Pass
target down.
* record-full.c (record_full_wait_1): Switch to event thread.
Pass target down.
* regcache.c (regcache::regcache)
(get_thread_arch_aspace_regcache, get_thread_arch_regcache): Add
process_stratum_target parameter and handle it.
(current_thread_target): New global.
(get_thread_regcache): Add process_stratum_target parameter and
handle it. Switch inferior before calling target method.
(get_thread_regcache): Pass target down.
(get_thread_regcache_for_ptid): Pass target down.
(registers_changed_ptid): Add process_stratum_target parameter and
handle it.
(registers_changed_thread, registers_changed): Pass target down.
(test_get_thread_arch_aspace_regcache): New.
(current_regcache_test): Define a couple local test_target_ops
instances and use them for testing.
(readwrite_regcache): Pass process_stratum_target parameter.
(cooked_read_test, cooked_write_test): Pass mock_target down.
* regcache.h (get_thread_regcache, get_thread_arch_regcache)
(get_thread_arch_aspace_regcache): Add process_stratum_target
parameter.
(regcache::target): New method.
(regcache::regcache, regcache::get_thread_arch_aspace_regcache)
(regcache::registers_changed_ptid): Add process_stratum_target
parameter.
(regcache::m_target): New field.
(registers_changed_ptid): Add process_stratum_target parameter.
* remote.c (remote_state::supports_vCont_probed): New field.
(remote_target::async_wait_fd): New method.
(remote_unpush_and_throw): Add remote_target parameter.
(get_current_remote_target): Adjust.
(remote_target::remote_add_inferior): Push target.
(remote_target::remote_add_thread)
(remote_target::remote_notice_new_inferior)
(get_remote_thread_info): Pass target down.
(remote_target::update_thread_list): Skip threads of inferiors
bound to other targets. (remote_target::close): Don't discard
inferiors. (remote_target::add_current_inferior_and_thread)
(remote_target::process_initial_stop_replies)
(remote_target::start_remote)
(remote_target::remote_serial_quit_handler): Pass down target.
(remote_target::remote_unpush_target): New remote_target
parameter. Unpush the target from all inferiors.
(remote_target::remote_unpush_and_throw): New remote_target
parameter. Pass it down.
(remote_target::open_1): Check whether the current inferior has
execution instead of checking whether any inferior is live. Pass
target down.
(remote_target::remote_detach_1): Pass down target. Use
remote_unpush_target.
(extended_remote_target::attach): Pass down target.
(remote_target::remote_vcont_probe): Set supports_vCont_probed.
(remote_target::append_resumption): Pass down target.
(remote_target::append_pending_thread_resumptions)
(remote_target::remote_resume_with_hc, remote_target::resume)
(remote_target::commit_resume): Pass down target.
(remote_target::remote_stop_ns): Check supports_vCont_probed.
(remote_target::interrupt_query)
(remote_target::remove_new_fork_children)
(remote_target::check_pending_events_prevent_wildcard_vcont)
(remote_target::remote_parse_stop_reply)
(remote_target::process_stop_reply): Pass down target.
(first_remote_resumed_thread): New remote_target parameter. Pass
it down.
(remote_target::wait_as): Pass down target.
(unpush_and_perror): New remote_target parameter. Pass it down.
(remote_target::readchar, remote_target::remote_serial_write)
(remote_target::getpkt_or_notif_sane_1)
(remote_target::kill_new_fork_children, remote_target::kill): Pass
down target.
(remote_target::mourn_inferior): Pass down target. Use
remote_unpush_target.
(remote_target::core_of_thread)
(remote_target::remote_btrace_maybe_reopen): Pass down target.
(remote_target::pid_to_exec_file)
(remote_target::thread_handle_to_thread_info): Pass down target.
(remote_target::async_wait_fd): New.
* riscv-fbsd-tdep.c: Include "inferior.h".
(riscv_fbsd_get_thread_local_address): Pass down target.
* sol2-tdep.c (sol2_core_pid_to_str): Pass down target.
* sol-thread.c (sol_thread_target::wait, ps_lgetregs, ps_lsetregs)
(ps_lgetfpregs, ps_lsetfpregs, sol_update_thread_list_callback):
Adjust.
* solib-spu.c (spu_skip_standalone_loader): Pass down target.
* solib-svr4.c (enable_break): Pass down target.
* spu-multiarch.c (parse_spufs_run): Pass down target.
* spu-tdep.c (spu2ppu_sniffer): Pass down target.
* target-delegates.c: Regenerate.
* target.c (g_target_stack): Delete.
(current_top_target): Return the current inferior's top target.
(target_has_execution_1): Refer to the passed-in inferior's top
target.
(target_supports_terminal_ours): Check whether the initial
inferior was already created.
(decref_target): New.
(target_stack::push): Incref/decref the target.
(push_target, push_target, unpush_target): Adjust.
(target_stack::unpush): Defref target.
(target_is_pushed): Return bool. Adjust to refer to the current
inferior's target stack.
(dispose_inferior): Delete, and inline parts ...
(target_preopen): ... here. Only dispose of the current inferior.
(target_detach): Hold strong target reference while detaching.
Pass target down.
(target_thread_name): Add assertion.
(target_resume): Pass down target.
(target_ops::beneath, find_target_at): Adjust to refer to the
current inferior's target stack.
(get_dummy_target): New.
(target_pass_ctrlc): Pass the Ctrl-C to the first inferior that
has a thread running.
(initialize_targets): Rename to ...
(_initialize_target): ... this.
* target.h: Include "gdbsupport/refcounted-object.h".
(struct target_ops): Inherit refcounted_object.
(target_ops::shortname, target_ops::longname): Make const.
(target_ops::async_wait_fd): New method.
(decref_target): Declare.
(struct target_ops_ref_policy): New.
(target_ops_ref): New typedef.
(get_dummy_target): Declare function.
(target_is_pushed): Return bool.
* thread-iter.c (all_matching_threads_iterator::m_inf_matches)
(all_matching_threads_iterator::all_matching_threads_iterator):
Handle filter target.
* thread-iter.h (struct all_matching_threads_iterator, struct
all_matching_threads_range, class all_non_exited_threads_range):
Filter by target too. Remove explicit.
* thread.c (threads_executing): Delete.
(inferior_thread): Pass down current inferior.
(clear_thread_inferior_resources): Pass down thread pointer
instead of ptid_t.
(add_thread_silent, add_thread_with_info, add_thread): Add
process_stratum_target parameter. Use it for thread and inferior
searches.
(is_current_thread): New.
(thread_info::deletable): Use it.
(find_thread_ptid, thread_count, in_thread_list)
(thread_change_ptid, set_resumed, set_running): New
process_stratum_target parameter. Pass it down.
(set_executing): New process_stratum_target parameter. Pass it
down. Adjust reference to 'threads_executing'.
(threads_are_executing): New process_stratum_target parameter.
Adjust reference to 'threads_executing'.
(set_stop_requested, finish_thread_state): New
process_stratum_target parameter. Pass it down.
(switch_to_thread): Also match inferior.
(switch_to_thread): New process_stratum_target parameter. Pass it
down.
(update_threads_executing): Reimplement.
* top.c (quit_force): Pop targets from all inferior.
(gdb_init): Don't call initialize_targets.
* windows-nat.c (windows_nat_target) <get_windows_debug_event>:
Declare.
(windows_add_thread, windows_delete_thread): Adjust.
(get_windows_debug_event): Rename to ...
(windows_nat_target::get_windows_debug_event): ... this. Adjust.
* tracefile-tfile.c (tfile_target_open): Pass down target.
* gdbsupport/common-gdbthread.h (struct process_stratum_target):
Forward declare.
(switch_to_thread): Add process_stratum_target parameter.
* mi/mi-interp.c (mi_on_resume_1): Add process_stratum_target
parameter. Use it.
(mi_on_resume): Pass target down.
* nat/fork-inferior.c (startup_inferior): Add
process_stratum_target parameter. Pass it down.
* nat/fork-inferior.h (startup_inferior): Add
process_stratum_target parameter.
* python/py-threadevent.c (py_get_event_thread): Pass target down.
gdb/gdbserver/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* fork-child.c (post_fork_inferior): Pass target down to
startup_inferior.
* inferiors.c (switch_to_thread): Add process_stratum_target
parameter.
* lynx-low.c (lynx_target_ops): Now a process_stratum_target.
* nto-low.c (nto_target_ops): Now a process_stratum_target.
* linux-low.c (linux_target_ops): Now a process_stratum_target.
* remote-utils.c (prepare_resume_reply): Pass the target to
switch_to_thread.
* target.c (the_target): Now a process_stratum_target.
(done_accessing_memory): Pass the target to switch_to_thread.
(set_target_ops): Ajust to use process_stratum_target.
* target.h (struct target_ops): Rename to ...
(struct process_stratum_target): ... this.
(the_target, set_target_ops): Adjust.
(prepare_to_access_memory): Adjust comment.
* win32-low.c (child_xfer_memory): Adjust to use
process_stratum_target.
(win32_target_ops): Now a process_stratum_target.
With the multi-target work, each inferior will have its own target
stack, so to call a target method, we'll need to make sure that the
inferior in question is the current one, otherwise target->beneath()
calls will find the target beneath in the wrong inferior.
In some places, it's much more convenient to be able to check whether
an inferior has execution without having to switch to it in order to
call target_has_execution on the right inferior/target stack, to avoid
side effects with switching inferior/thread/program space.
The current target_ops::has_execution method takes a ptid_t as
parameter, which, in a multi-target world, isn't sufficient to
identify the target. This patch prepares to address that, by changing
the parameter to an inferior pointer instead. From the inferior,
we'll be able to query its target stack to tell which target is
beneath.
Also adds a new inferior::has_execution() method to make callers a bit
more natural to read.
gdb/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* corelow.c (core_target::has_execution): Change parameter type to
inferior pointer.
* inferior.c (number_of_live_inferiors): Use
inferior::has_execution instead of target_has_execution_1.
* inferior.h (inferior::has_execution): New.
* linux-thread-db.c (thread_db_target::update_thread_list): Use
inferior::has_execution instead of target_has_execution_1.
* process-stratum-target.c
(process_stratum_target::has_execution): Change parameter type to
inferior pointer. Check the inferior's PID instead of
inferior_ptid.
* process-stratum-target.h
(process_stratum_target::has_execution): Change parameter type to
inferior pointer.
* record-full.c (record_full_core_target::has_execution): Change
parameter type to inferior pointer.
* target.c (target_has_execution_1): Change parameter type to
inferior pointer.
(target_has_execution_current): Adjust.
* target.h (target_ops::has_execution): Change parameter type to
inferior pointer.
(target_has_execution_1): Change parameter type to inferior
pointer. Change return type to bool.
* tracefile.h (tracefile_target::has_execution): Change parameter
type to inferior pointer.
Ref.: https://bugzilla.redhat.com/show_bug.cgi?id=1765117
A segfault can happen in a specific scenario when using TUI + a
corefile, as explained in the bug mentioned above. The problem
happens when opening a corefile on GDB:
$ gdb ./core program
entering TUI (C-x a), and then issuing a "run" command. GDB segfaults
with the following stack trace:
(top-gdb) bt
#0 0x00000000004cd5da in target_ops::shortname (this=0x0) at ../../binutils-gdb/gdb/target.h:449
#1 0x0000000000ac08fb in target_shortname () at ../../binutils-gdb/gdb/target.h:1323
#2 0x0000000000ac09ae in tui_locator_window::make_status_line[abi:cxx11]() const (this=0x23e1fa0 <_locator>) at ../../binutils-gdb/gdb/tui/tui-stack.c:86
#3 0x0000000000ac1043 in tui_locator_window::rerender (this=0x23e1fa0 <_locator>) at ../../binutils-gdb/gdb/tui/tui-stack.c:231
#4 0x0000000000ac1632 in tui_show_locator_content () at ../../binutils-gdb/gdb/tui/tui-stack.c:369
#5 0x0000000000ac63b6 in tui_set_key_mode (mode=TUI_COMMAND_MODE) at ../../binutils-gdb/gdb/tui/tui.c:321
#6 0x0000000000aaf9be in tui_inferior_exit (inf=0x2d446a0) at ../../binutils-gdb/gdb/tui/tui-hooks.c:181
#7 0x000000000044cddf in std::_Function_handler<void (inferior*), void (*)(inferior*)>::_M_invoke(std::_Any_data const&, inferior*&&) (__functor=..., __args#0=@0x7fffffffd650: 0x2d446a0)
at /usr/include/c++/9/bits/std_function.h:300
#8 0x0000000000757db9 in std::function<void (inferior*)>::operator()(inferior*) const (this=0x2cf3168, __args#0=0x2d446a0) at /usr/include/c++/9/bits/std_function.h:690
#9 0x0000000000757876 in gdb::observers::observable<inferior*>::notify (this=0x23de0c0 <gdb::observers::inferior_exit>, args#0=0x2d446a0)
at ../../binutils-gdb/gdb/gdbsupport/observable.h:106
#10 0x000000000075532d in exit_inferior_1 (inftoex=0x2d446a0, silent=1) at ../../binutils-gdb/gdb/inferior.c:191
#11 0x0000000000755460 in exit_inferior_silent (inf=0x2d446a0) at ../../binutils-gdb/gdb/inferior.c:234
#12 0x000000000059f47c in core_target::close (this=0x2d68590) at ../../binutils-gdb/gdb/corelow.c:265
#13 0x0000000000a7688c in target_close (targ=0x2d68590) at ../../binutils-gdb/gdb/target.c:3293
#14 0x0000000000a63d74 in target_stack::push (this=0x23e1800 <g_target_stack>, t=0x23c38c8 <the_amd64_linux_nat_target>) at ../../binutils-gdb/gdb/target.c:568
#15 0x0000000000a63dbf in push_target (t=0x23c38c8 <the_amd64_linux_nat_target>) at ../../binutils-gdb/gdb/target.c:583
#16 0x0000000000748088 in inf_ptrace_target::create_inferior (this=0x23c38c8 <the_amd64_linux_nat_target>, exec_file=0x2d58d30 "/usr/bin/cat", allargs="", env=0x25f12b0, from_tty=1)
at ../../binutils-gdb/gdb/inf-ptrace.c:128
#17 0x0000000000795ccb in linux_nat_target::create_inferior (this=0x23c38c8 <the_amd64_linux_nat_target>, exec_file=0x2d58d30 "/usr/bin/cat", allargs="", env=0x25f12b0, from_tty=1)
at ../../binutils-gdb/gdb/linux-nat.c:1094
#18 0x000000000074eae9 in run_command_1 (args=0x0, from_tty=1, run_how=RUN_NORMAL) at ../../binutils-gdb/gdb/infcmd.c:639
...
The problem happens because 'tui_locator_window::make_status_line'
needs the value of 'target_shortname' in order to update the status
line. 'target_shortname' is a macro which expands to:
#define target_shortname (current_top_target ()->shortname ())
and, in our scenario, 'current_top_target ()' returns NULL, which
obviously causes a segfault. But why does it return NULL, since,
according to its comment on target.h, it should never do that?
What is happening is that we're being caught in the middle of a
"target switch". We had the 'core_target' on top, because we were
inspecting a corefile, but when the user decided to invoke "run" GDB
had to actually create the inferior, which ends up detecting that we
have a target already, and tries to close it (from target.c):
/* See target.h. */
void
target_stack::push (target_ops *t)
{
/* If there's already a target at this stratum, remove it. */
strata stratum = t->stratum ();
if (m_stack[stratum] != NULL)
{
target_ops *prev = m_stack[stratum];
m_stack[stratum] = NULL;
target_close (prev); // <-- here
}
...
When the current target ('core_target') is being closed, it checks for
possible observers registered with it and calls them. TUI is one of
those observers, it gets called, tries to update the status line, and
GDB crashes.
The real problem is that we are clearing 'm_stack[stratum]', but
forgetting to adjust 'm_top'. Interestingly, this scenario is covered
in 'target_stack::unpush', but Pedro said he forgot to call it here..
The fix, therefore, is to call '::unpush' if there's a target on the
stack.
This patch has been tested on the Buildbot and no regressions have
been found. I'm also submitting a testcase for it.
gdb/ChangeLog:
2019-11-18 Sergio Durigan Junior <sergiodj@redhat.com>
Pedro Alves <palves@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1765117
* target.c (target_stack::push): Call 'unpush' if there's a
target on top of the stack.
gdb/testsuite/ChangeLog:
2019-11-18 Sergio Durigan Junior <sergiodj@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1765117
* gdb.tui/corefile-run.exp: New file.
Change-Id: I39e2f8b538c580c8ea5bf1d657ee877e47746c8f
This replaces uses of field_fmt with a "%s" format string to use
field_string instead. Also, one use of "%9lx" is replaced with a call
to phex_nz; the '9' is dropped as it is implicit in the field width.
2019-07-15 Tom Tromey <tromey@adacore.com>
* mi/mi-main.c (list_available_thread_groups): Use field_string.
* mi/mi-interp.c (mi_memory_changed): Use field_string.
* target.c (flash_erase_command): Use field_string.
* infrun.c (print_signal_received_reason): Use field_string.
* i386-tdep.c (i386_mpx_print_bounds): Use field_string.
* breakpoint.c (maybe_print_thread_hit_breakpoint): Use
field_string.
* ada-tasks.c (print_ada_task_info): Use field_string.
This changes a few spots that use field_fmt to use field_core_addr
instead.
gdb/ChangeLog
2019-07-15 Tom Tromey <tromey@adacore.com>
* target.c (flash_erase_command): Use field_core_addr.
* symfile.c (generic_load): Use field_core_addr.
* sparc64-linux-tdep.c (sparc64_linux_handle_segmentation_fault):
Use field_core_addr.
* i386-linux-tdep.c (i386_linux_handle_segmentation_fault): Use
field_core_addr.
Adds an utility function to make it shorter to write the common case
of wrapping an xstrdup with a unique_xmalloc_ptr, and uses it
throughout.
Note: I tried to put this in common/common-utils.h near skip_spaces,
etc. but that is included in common/common-defs.h before
common/gdb_unique_ptr.h is included, so it would fail to compile
because gdb::unique_xmalloc_ptr isn't defined at that point yet. I
tried moving the gdb_unique_ptr.h inclusion before common-utils.h, but
that doesn't work because gdb_unique_ptr.h depends on common-utils.h
for xfree.
gdb/ChangeLog:
2019-06-04 Pedro Alves <palves@redhat.com>
* common/gdb_unique_ptr.h (make_unique_xstrdup): New.
* ada-lang.c (catch_ada_completer): Use make_unique_xstrdup.
* breakpoint.c (condition_completer): Likewise.
* cli/cli-dump.c (scan_expression): Likewise.
* common/filestuff.c (mkdir_recursive): Likewise.
* common/gdb_tilde_expand.c (gdb_tilde_expand_up)
* common/pathstuff.c (gdb_realpath, gdb_realpath_keepfile)
(gdb_abspath): Likewise.
* compile/compile-cplus-types.c
(compile_cplus_instance::decl_name): Likewise.
* completer.c (complete_explicit_location):
(signal_completer, reg_or_group_completer_1): Likewise.
* cp-support.c (cp_remove_params_if_any): Likewise.
* fbsd-tdep.c (fbsd_core_vnode_path): Likewise.
* guile/scm-safe-call.c (gdbscm_safe_eval_string): Likewise.
* infcmd.c (strip_bg_char): Likewise.
* linespec.c (copy_token_string): Likewise.
* mi/mi-main.c (output_cores): Likewise.
* psymtab.c (psymtab_search_name):
* symfile.c (test_set_ext_lang_command): Likewise.
* target.c (target_fileio_read_stralloc): Likewise.
* tui/tui-regs.c (tui_reggroup_completer): Likewise.
* value.c (complete_internalvar): Likewise.
gdb/gdbserver/ChangeLog:
2019-06-04 Pedro Alves <palves@redhat.com>
* server.c (captured_main): Use make_unique_xstrdup.
I noticed that target_ops::follow_exec took a "char *" parameter,
where "const char *" would be more correct. This patch changes this
(and related functions) to be constified.
Tested by rebuilding.
gdb/ChangeLog
2019-05-22 Tom Tromey <tromey@adacore.com>
* target.c (target_follow_exec): Constify parameter.
* target-delegates.c: Rebuild.
* remote.c (remote_target::follow_exec): Constify parameter.
* infrun.c (follow_exec): Constify parameter.
* target.h (struct target_ops) <follow_exec>: Constify parameter.
(target_follow_exec): Likewise.
This rewrites gdb's TRY/CATCH to plain C++ try/catch. The patch was
largely written by script, though one change (to a comment in
common-exceptions.h) was reverted by hand.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c: Use C++ exception handling.
* x86-linux-nat.c: Use C++ exception handling.
* windows-nat.c: Use C++ exception handling.
* varobj.c: Use C++ exception handling.
* value.c: Use C++ exception handling.
* valprint.c: Use C++ exception handling.
* valops.c: Use C++ exception handling.
* unittests/parse-connection-spec-selftests.c: Use C++ exception
handling.
* unittests/cli-utils-selftests.c: Use C++ exception handling.
* typeprint.c: Use C++ exception handling.
* tui/tui.c: Use C++ exception handling.
* tracefile-tfile.c: Use C++ exception handling.
* top.c: Use C++ exception handling.
* thread.c: Use C++ exception handling.
* target.c: Use C++ exception handling.
* symmisc.c: Use C++ exception handling.
* symfile-mem.c: Use C++ exception handling.
* stack.c: Use C++ exception handling.
* sparc64-linux-tdep.c: Use C++ exception handling.
* solib.c: Use C++ exception handling.
* solib-svr4.c: Use C++ exception handling.
* solib-spu.c: Use C++ exception handling.
* solib-frv.c: Use C++ exception handling.
* solib-dsbt.c: Use C++ exception handling.
* selftest-arch.c: Use C++ exception handling.
* s390-tdep.c: Use C++ exception handling.
* rust-lang.c: Use C++ exception handling.
* rust-exp.y: Use C++ exception handling.
* rs6000-tdep.c: Use C++ exception handling.
* rs6000-aix-tdep.c: Use C++ exception handling.
* riscv-tdep.c: Use C++ exception handling.
* remote.c: Use C++ exception handling.
* remote-fileio.c: Use C++ exception handling.
* record-full.c: Use C++ exception handling.
* record-btrace.c: Use C++ exception handling.
* python/python.c: Use C++ exception handling.
* python/py-value.c: Use C++ exception handling.
* python/py-utils.c: Use C++ exception handling.
* python/py-unwind.c: Use C++ exception handling.
* python/py-type.c: Use C++ exception handling.
* python/py-symbol.c: Use C++ exception handling.
* python/py-record.c: Use C++ exception handling.
* python/py-record-btrace.c: Use C++ exception handling.
* python/py-progspace.c: Use C++ exception handling.
* python/py-prettyprint.c: Use C++ exception handling.
* python/py-param.c: Use C++ exception handling.
* python/py-objfile.c: Use C++ exception handling.
* python/py-linetable.c: Use C++ exception handling.
* python/py-lazy-string.c: Use C++ exception handling.
* python/py-infthread.c: Use C++ exception handling.
* python/py-inferior.c: Use C++ exception handling.
* python/py-gdb-readline.c: Use C++ exception handling.
* python/py-framefilter.c: Use C++ exception handling.
* python/py-frame.c: Use C++ exception handling.
* python/py-finishbreakpoint.c: Use C++ exception handling.
* python/py-cmd.c: Use C++ exception handling.
* python/py-breakpoint.c: Use C++ exception handling.
* python/py-arch.c: Use C++ exception handling.
* printcmd.c: Use C++ exception handling.
* ppc-linux-tdep.c: Use C++ exception handling.
* parse.c: Use C++ exception handling.
* p-valprint.c: Use C++ exception handling.
* objc-lang.c: Use C++ exception handling.
* mi/mi-main.c: Use C++ exception handling.
* mi/mi-interp.c: Use C++ exception handling.
* mi/mi-cmd-stack.c: Use C++ exception handling.
* mi/mi-cmd-break.c: Use C++ exception handling.
* main.c: Use C++ exception handling.
* linux-thread-db.c: Use C++ exception handling.
* linux-tdep.c: Use C++ exception handling.
* linux-nat.c: Use C++ exception handling.
* linux-fork.c: Use C++ exception handling.
* linespec.c: Use C++ exception handling.
* language.c: Use C++ exception handling.
* jit.c: Use C++ exception handling.
* infrun.c: Use C++ exception handling.
* infcmd.c: Use C++ exception handling.
* infcall.c: Use C++ exception handling.
* inf-loop.c: Use C++ exception handling.
* i386-tdep.c: Use C++ exception handling.
* i386-linux-tdep.c: Use C++ exception handling.
* guile/scm-value.c: Use C++ exception handling.
* guile/scm-type.c: Use C++ exception handling.
* guile/scm-symtab.c: Use C++ exception handling.
* guile/scm-symbol.c: Use C++ exception handling.
* guile/scm-pretty-print.c: Use C++ exception handling.
* guile/scm-ports.c: Use C++ exception handling.
* guile/scm-param.c: Use C++ exception handling.
* guile/scm-math.c: Use C++ exception handling.
* guile/scm-lazy-string.c: Use C++ exception handling.
* guile/scm-frame.c: Use C++ exception handling.
* guile/scm-disasm.c: Use C++ exception handling.
* guile/scm-cmd.c: Use C++ exception handling.
* guile/scm-breakpoint.c: Use C++ exception handling.
* guile/scm-block.c: Use C++ exception handling.
* guile/guile-internal.h: Use C++ exception handling.
* gnu-v3-abi.c: Use C++ exception handling.
* gdbtypes.c: Use C++ exception handling.
* frame.c: Use C++ exception handling.
* frame-unwind.c: Use C++ exception handling.
* fbsd-tdep.c: Use C++ exception handling.
* f-valprint.c: Use C++ exception handling.
* exec.c: Use C++ exception handling.
* event-top.c: Use C++ exception handling.
* event-loop.c: Use C++ exception handling.
* eval.c: Use C++ exception handling.
* dwarf2read.c: Use C++ exception handling.
* dwarf2loc.c: Use C++ exception handling.
* dwarf2-frame.c: Use C++ exception handling.
* dwarf2-frame-tailcall.c: Use C++ exception handling.
* dwarf-index-write.c: Use C++ exception handling.
* dwarf-index-cache.c: Use C++ exception handling.
* dtrace-probe.c: Use C++ exception handling.
* disasm-selftests.c: Use C++ exception handling.
* darwin-nat.c: Use C++ exception handling.
* cp-valprint.c: Use C++ exception handling.
* cp-support.c: Use C++ exception handling.
* cp-abi.c: Use C++ exception handling.
* corelow.c: Use C++ exception handling.
* completer.c: Use C++ exception handling.
* compile/compile-object-run.c: Use C++ exception handling.
* compile/compile-object-load.c: Use C++ exception handling.
* compile/compile-cplus-symbols.c: Use C++ exception handling.
* compile/compile-c-symbols.c: Use C++ exception handling.
* common/selftest.c: Use C++ exception handling.
* common/new-op.c: Use C++ exception handling.
* cli/cli-script.c: Use C++ exception handling.
* cli/cli-interp.c: Use C++ exception handling.
* cli/cli-cmds.c: Use C++ exception handling.
* c-varobj.c: Use C++ exception handling.
* btrace.c: Use C++ exception handling.
* breakpoint.c: Use C++ exception handling.
* break-catch-throw.c: Use C++ exception handling.
* arch-utils.c: Use C++ exception handling.
* amd64-tdep.c: Use C++ exception handling.
* ada-valprint.c: Use C++ exception handling.
* ada-typeprint.c: Use C++ exception handling.
* ada-lang.c: Use C++ exception handling.
* aarch64-tdep.c: Use C++ exception handling.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c: Use C++ exception handling.
* linux-low.c: Use C++ exception handling.
* gdbreplay.c: Use C++ exception handling.
Commit 799efbe8e0 was supposed to fix
the below leak. However, for this fix to work, it is critical to
save the ptid before detach.
This commit (pushed as OBVIOUS, as the change was already reviewed/approved)
saves the ptid before the detach, as in the original reviewed patch
(see https://sourceware.org/ml/gdb-patches/2019-02/msg00263.html).
Re-tested on debian/amd64, natively and under valgrind.
==7426== 1,123 (72 direct, 1,051 indirect) bytes in 1 blocks are definitely lost in loss record 2,872 of 3,020
==7426== at 0x4C2C4CC: operator new(unsigned long) (vg_replace_malloc.c:344)
==7426== by 0x5BD1E1: get_thread_arch_aspace_regcache(ptid_t, gdbarch*, address_space*) (regcache.c:330)
==7426== by 0x5BD39A: get_thread_regcache (regcache.c:366)
==7426== by 0x5BD39A: get_current_regcache() (regcache.c:372)
==7426== by 0x4B1EB4: get_current_frame() (frame.c:1588)
...
Permit TLS variable addresses to be resolved purely by an ABI rather
than requiring a target method. This doesn't try the target method if
the ABI function is present (even if the ABI function fails) to
simplify error handling.
gdb/ChangeLog:
* gdbarch.sh (get_thread_local_address): New method.
* gdbarch.h, gdbarch.c: Regenerate.
* target.c (target_translate_tls_address): Use
gdbarch_get_thread_local_address if present instead of
target::get_thread_local_address.
While debugging gdb, I printed the target stack and got:
(top-gdb) p g_target_stack
$10 = {
m_top = thread_stratum,
m_stack = {0x142b0b0, 0x13da600 <exec_ops>, 0x1c70690, 0x13d63b0 <ravenscar_ops>, 0x0, 0x0, 0x0}
}
(This is clearly from before the change to make ravenscar
multi-target-capable.)
Here, 0x142b0b0 is the singleton dummy target. It seems to me that
since this is always a singleton, it would be a bit nicer if it were a
global, so that it would be noted in the above.
This patch implements this idea, and now I get:
(top-gdb) p g_target_stack
$2 = {
m_top = dummy_stratum,
m_stack = {0x1f1b040 <the_dummy_target>, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}
}
I did not do the same for the debug target. It didn't seem as useful
to me.
gdb/ChangeLog
2019-03-05 Tom Tromey <tromey@adacore.com>
* target.c (the_dummy_target): Move later. Change type to
"dummy_target".
(initialize_targets): Don't initialize the_dummy_target.
A customer noticed some mildly odd MI output, where CLI output was
split into multiple MI strings at unusual boundaries, like this:
~"$1 = (b => true"
~", p => 0x407260"
This is technically correct according to the MI spec, but still
unusual, in that there's no particular reason for the string to be
split where it is.
I tracked this down to a call to gdb_flush in generic_val_print.
Then, I went through all calls to gdb_flush and removed the ones I
thought were superfluous. In particular:
* Any call in the value-printing code;
* Likewise the type-printing code (just a single call); and
* Any call that immediately followed a printf that obviously
ended with a newline, my belief being that gdb's standard output
streams are line buffered (by inheriting the behavior from stdio)
Regression tested on x86-64 Fedora 29.
I didn't add a new test case. I tend to think we don't necessarily
want to specify this behavior in the tests. Let me know what you
think of this.
gdb/ChangeLog
2019-03-05 Tom Tromey <tromey@adacore.com>
* windows-nat.c (windows_nat_target::attach)
(windows_nat_target::detach): Don't call gdb_flush.
* valprint.c (generic_val_print, val_print, val_print_string):
Don't call gdb_flush.
* utils.c (defaulted_query): Don't call gdb_flush.
* typeprint.c (print_type_scalar): Don't call gdb_flush.
* target.c (target_announce_detach): Don't call gdb_flush.
* sparc64-tdep.c (adi_print_versions): Don't call gdb_flush.
* remote.c (extended_remote_target::attach): Don't call
gdb_flush.
* procfs.c (procfs_target::detach): Don't call gdb_flush.
* printcmd.c (do_examine): Don't call gdb_flush.
(info_display_command): Don't call gdb_flush.
* p-valprint.c (pascal_val_print): Don't call gdb_flush.
* nto-procfs.c (nto_procfs_target::attach): Don't call gdb_flush.
* memattr.c (info_mem_command): Don't call gdb_flush.
* mdebugread.c (mdebug_build_psymtabs): Don't call gdb_flush.
* m2-valprint.c (m2_val_print): Don't call gdb_flush.
* infrun.c (follow_exec, handle_command): Don't call gdb_flush.
* inf-ptrace.c (inf_ptrace_target::attach): Don't call gdb_flush.
* hppa-tdep.c (unwind_command): Don't call gdb_flush.
* gnu-nat.c (gnu_nat_target::attach): Don't call gdb_flush.
(gnu_nat_target::detach): Don't call gdb_flush.
* f-valprint.c (f_val_print): Don't call gdb_flush.
* darwin-nat.c (darwin_nat_target::attach): Don't call gdb_flush.
* cli/cli-script.c (read_command_lines): Don't call gdb_flush.
* cli/cli-cmds.c (shell_escape, print_disassembly): Don't call
gdb_flush.
* c-valprint.c (c_val_print): Don't call gdb_flush.
* ada-valprint.c (ada_print_scalar): Don't call gdb_flush.
Valgrind reports leaks like the below in various tests,
e.g. gdb.threads/attach-slow-waitpid.exp, gdb.ada/task_switch_in_core.exp, ...
Fix the leak by clearing the regcache when detaching from an inferior.
Note that these leaks are 'created' when GDB exits,
when the regcache::current_regcache is destroyed : the elements
of the forward_list are pointers, and the 'pointed to' memory is not
deleted by the forward_list destructor.
Nevertheless, fixing this leak is good as it makes a bunch of
tests 'leak clean'.
Also, it seems strange to keep a register cache for a process from
which GDB detached : it is not clear if this cache is still valid
after detach. And effectively, when clearing only the regcache,
(and not the frame cache), then the frame cache was still 'pointing'
at this regcache and was used when switching to the child process
in the test gdb.threads/watchpoint-fork.exp, which seems strange.
So, we solve the leak and avoid possible accesses to the regcache
and frame cache of the detached inferior, by clearing both the
regcache and the frame cache.
Tested on debian/amd64, natively, under Valgrind,
and with make check RUNTESTFLAGS="--target_board=native-gdbserver".
==27679== VALGRIND_GDB_ERROR_BEGIN
==27679== 1,123 (72 direct, 1,051 indirect) bytes in 1 blocks are definitely lost in loss record 2,942 of 3,400
==27679== at 0x4C2C4CC: operator new(unsigned long) (vg_replace_malloc.c:344)
==27679== by 0x5CDF71: get_thread_arch_aspace_regcache(ptid_t, gdbarch*, address_space*) (regcache.c:330)
==27679== by 0x5CE12A: get_thread_regcache (regcache.c:366)
==27679== by 0x5CE12A: get_current_regcache() (regcache.c:372)
==27679== by 0x4FF63D: post_create_inferior(target_ops*, int) (infcmd.c:452)
==27679== by 0x43AF62: core_target_open(char const*, int) (corelow.c:458)
==27679== by 0x408B68: cmd_func(cmd_list_element*, char const*, int) (cli-decode.c:1892)
...
gdb/ChangeLog
2019-02-27 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* target.c (target_detach): Clear the regcache and the
frame cache.
Simon Marchi