Commit Graph

247 Commits

Author SHA1 Message Date
Simon Marchi
5b9707eb87 gdb: remove gdbcmd.h
Most files including gdbcmd.h currently rely on it to access things
actually declared in cli/cli-cmds.h (setlist, showlist, etc).  To make
things easy, replace all includes of gdbcmd.h with includes of
cli/cli-cmds.h.  This might lead to some unused includes of
cli/cli-cmds.h, but it's harmless, and much faster than going through
the 170 or so files by hand.

Change-Id: I11f884d4d616c12c05f395c98bbc2892950fb00f
Approved-By: Tom Tromey <tom@tromey.com>
2024-04-25 12:59:02 -04:00
Simon Marchi
824dd26e97 gdb: move execute function declarations from gdbcmd.h to top.h
These functions are implemented in top.c, move their declarations to
top.h.

Change-Id: I8893ef91d955156a6530734fefe8002d78c3e5fc
Approved-By: Tom Tromey <tom@tromey.com>
2024-04-25 12:58:49 -04:00
Simon Marchi
18d2988e5d gdb, gdbserver, gdbsupport: remove includes of early headers
Now that defs.h, server.h and common-defs.h are included via the
`-include` option, it is no longer necessary for source files to include
them.  Remove all the inclusions of these files I could find.  Update
the generation scripts where relevant.

Change-Id: Ia026cff269c1b7ae7386dd3619bc9bb6a5332837
Approved-By: Pedro Alves <pedro@palves.net>
2024-03-26 21:13:22 -04:00
Simon Marchi
8480a37e14 gdb: pass frames as const frame_info_ptr &
We currently pass frames to function by value, as `frame_info_ptr`.
This is somewhat expensive:

 - the size of `frame_info_ptr` is 64 bytes, which is a bit big to pass
   by value
 - the constructors and destructor link/unlink the object in the global
   `frame_info_ptr::frame_list` list.  This is an `intrusive_list`, so
   it's not so bad: it's just assigning a few points, there's no memory
   allocation as if it was `std::list`, but still it's useless to do
   that over and over.

As suggested by Tom Tromey, change many function signatures to accept
`const frame_info_ptr &` instead of `frame_info_ptr`.

Some functions reassign their `frame_info_ptr` parameter, like:

  void
  the_func (frame_info_ptr frame)
  {
    for (; frame != nullptr; frame = get_prev_frame (frame))
      {
        ...
      }
  }

I wondered what to do about them, do I leave them as-is or change them
(and need to introduce a separate local variable that can be
re-assigned).  I opted for the later for consistency.  It might not be
clear why some functions take `const frame_info_ptr &` while others take
`frame_info_ptr`.  Also, if a function took a `frame_info_ptr` because
it did re-assign its parameter, I doubt that we would think to change it
to `const frame_info_ptr &` should the implementation change such that
it doesn't need to take `frame_info_ptr` anymore.  It seems better to
have a simple rule and apply it everywhere.

Change-Id: I59d10addef687d157f82ccf4d54f5dde9a963fd0
Approved-By: Andrew Burgess <aburgess@redhat.com>
2024-02-20 10:42:25 -05:00
Andrew Burgess
1d506c26d9 Update copyright year range in header of all files managed by GDB
This commit is the result of the following actions:

  - Running gdb/copyright.py to update all of the copyright headers to
    include 2024,

  - Manually updating a few files the copyright.py script told me to
    update, these files had copyright headers embedded within the
    file,

  - Regenerating gdbsupport/Makefile.in to refresh it's copyright
    date,

  - Using grep to find other files that still mentioned 2023.  If
    these files were updated last year from 2022 to 2023 then I've
    updated them this year to 2024.

I'm sure I've probably missed some dates.  Feel free to fix them up as
you spot them.
2024-01-12 15:49:57 +00:00
Tom Tromey
d182e39881 Use C++17 [[fallthrough]] attribute
This changes gdb to use the C++17 [[fallthrough]] attribute rather
than special comments.

This was mostly done by script, but I neglected a few spellings and so
also fixed it up by hand.

I suspect this fixes the bug mentioned below, by switching to a
standard approach that, presumably, clang supports.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=23159
Approved-By: John Baldwin <jhb@FreeBSD.org>
Approved-By: Luis Machado <luis.machado@arm.com>
Approved-By: Pedro Alves <pedro@palves.net>
2023-11-29 14:29:43 -07:00
Tom de Vries
f9582a22db [gdb] Fix segfault in for_each_block, part 1
When running test-case gdb.base/vfork-follow-parent.exp on powerpc64 (likewise
on s390x), I run into:
...
(gdb) PASS: gdb.base/vfork-follow-parent.exp: \
  exec_file=vfork-follow-parent-exit: target-non-stop=on: non-stop=off: \
  resolution_method=schedule-multiple: print unblock_parent = 1
continue^M
Continuing.^M
Reading symbols from vfork-follow-parent-exit...^M
^M
^M
Fatal signal: Segmentation fault^M
----- Backtrace -----^M
0x1027d3e7 gdb_internal_backtrace_1^M
        src/gdb/bt-utils.c:122^M
0x1027d54f _Z22gdb_internal_backtracev^M
        src/gdb/bt-utils.c:168^M
0x1057643f handle_fatal_signal^M
        src/gdb/event-top.c:889^M
0x10576677 handle_sigsegv^M
        src/gdb/event-top.c:962^M
0x3fffa7610477 ???^M
0x103f2144 for_each_block^M
        src/gdb/dcache.c:199^M
0x103f235b _Z17dcache_invalidateP13dcache_struct^M
        src/gdb/dcache.c:251^M
0x10bde8c7 _Z24target_dcache_invalidatev^M
        src/gdb/target-dcache.c:50^M
...
or similar.

The root cause for the segmentation fault is that linux_is_uclinux gives an
incorrect result: it should always return false, given that we're running on a
regular linux system, but instead it returns first true, then false.

In more detail, the segmentation fault happens as follows:
- a program space with an address space is created
- a second program space is about to be created. maybe_new_address_space
  is called, and because linux_is_uclinux returns true, maybe_new_address_space
  returns false, and no new address space is created
- a second program space with the same address space is created
- a program space is deleted. Because linux_is_uclinux now returns false,
  gdbarch_has_shared_address_space (current_inferior ()->arch ()) returns
  false, and the address space is deleted
- when gdb uses the address space of the remaining program space, we run into
  the segfault, because the address space is deleted.

Hardcoding linux_is_uclinux to false makes the test-case pass.

We leave addressing the root cause for the following commit in this series.

For now, prevent the segmentation fault by making the address space a refcounted
object.

This was already suggested here [1]:
...
A better solution might be to have the address spaces be reference counted
...

Tested on top of trunk on x86_64-linux and ppc64le-linux.
Tested on top of gdb-14-branch on ppc64-linux.

Co-Authored-By: Simon Marchi <simon.marchi@polymtl.ca>

PR gdb/30547
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30547

[1] https://sourceware.org/pipermail/gdb-patches/2023-October/202928.html
2023-11-28 10:31:25 +01:00
Lancelot Six
6b09f1342c gdb: Replace gdb::optional with std::optional
Since GDB now requires C++17, we don't need the internally maintained
gdb::optional implementation.  This patch does the following replacing:
  - gdb::optional -> std::optional
  - gdb::in_place -> std::in_place
  - #include "gdbsupport/gdb_optional.h" -> #include <optional>

This change has mostly been done automatically.  One exception is
gdbsupport/thread-pool.* which did not use the gdb:: prefix as it
already lives in the gdb namespace.

Change-Id: I19a92fa03e89637bab136c72e34fd351524f65e9
Approved-By: Tom Tromey <tom@tromey.com>
Approved-By: Pedro Alves <pedro@palves.net>
2023-11-21 11:52:35 +00:00
Simon Marchi
9c742269ec gdb: remove get_current_regcache
Remove get_current_regcache, inlining the call to get_thread_regcache in
callers.  When possible, pass the right thread_info object known from
the local context.  Otherwise, fall back to passing `inferior_thread ()`.

This makes the reference to global context bubble up one level, a small
step towards the long term goal of reducing the number of references to
global context (or rather, moving those references as close as possible
to the top of the call tree).

No behavior change expected.

Change-Id: Ifa6980c88825d803ea586546b6b4c633c33be8d6
2023-11-17 20:01:37 +00:00
Simon Marchi
99d9c3b92c gdb: remove target_gdbarch
This function is just a wrapper around the current inferior's gdbarch.
I find that having that wrapper just obscures where the arch is coming
from, and that it's often used as "I don't know which arch to use so
I'll use this magical target_gdbarch function that gets me an arch" when
the arch should in fact come from something in the context (a thread,
objfile, symbol, etc).  I think that removing it and inlining
`current_inferior ()->arch ()` everywhere will make it a bit clearer
where that arch comes from and will trigger people into reflecting
whether this is the right place to get the arch or not.

Change-Id: I79f14b4e4934c88f91ca3a3155f5fc3ea2fadf6b
Reviewed-By: John Baldwin <jhb@FreeBSD.org>
Approved-By: Andrew Burgess <aburgess@redhat.com>
2023-10-10 10:44:35 -04:00
Tom Tromey
0434c3ef8d Use "unrelocated" terminology in linetable_entry
I forgot to convert struct linetable_entry to use the "unrelocated"
(as opposed to "raw") terminology.  This patch corrects the oversight.
2023-06-05 09:59:18 -06:00
Simon Marchi
44fbffc69d gdb: add interp::on_record_changed method
Same idea as previous patches, but for record_changed

Change-Id: I5eeeacd703af8401c315060514c94e8e6439cc40
2023-05-30 15:07:26 -04:00
Simon Marchi
2b214d3e3b gdb: remove regcache::target
The regcache class takes a process_stratum_target and then exposes it
through regcache::target.  But it doesn't use it itself, suggesting it
doesn't really make sense to put it there.  The only user of
regcache::target is record_btrace_target::fetch_registers, but it might
as well just get it from the current target stack.  This simplifies a
little bit a patch later in this series.

Change-Id: I8878d875805681c77f469ac1a2bf3a508559a62d
Reviewed-By: Pedro Alves <pedro@palves.net>
2023-04-17 13:47:13 -04:00
Simon Marchi
9213a6d79a gdb: make find_thread_ptid a process_stratum_target method
Make find_thread_ptid (the overload that takes a process_stratum_target)
a method of process_stratum_target.

Change-Id: Ib190a925a83c6b93e9c585dc7c6ab65efbdd8629
Reviewed-By: Tom Tromey <tom@tromey.com>
2023-04-04 21:05:31 -04:00
Tom Tromey
48e0f38c30 Fix line table regression
Simon pointed out a line table regression, and after a couple of false
starts, I was able to reproduce it by hand using his instructions.

The bug is that most of the code in do_mixed_source_and_assembly uses
unrelocated addresses, but one spot does:

  pc = low;

... after the text offset has been removed.

This patch fixes the problem by introducing a new type to represent
unrelocated addresses in the line table.  This prevents this sort of
bug to some degree (it's still possible to manipulate a CORE_ADDR in a
bad way, this is unavoidable).

However, this did let the compiler flag a few spots in that function,
and now it's not possible to compare an unrelocated address from a
line table with an ordinary CORE_ADDR.

Regression tested on x86-64 Fedora 36, though note this setup never
reproduced the bug in the first place.  I also tested it by hand on
the disasm-optim test program.
2023-03-17 16:17:43 -06:00
Tom Tromey
ddc6677b17 Change linetable_entry::is_stmt to bool
This changes linetable_entry::is_stmt to type bool, rather than
unsigned.

Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-03-11 08:48:29 -07:00
Tom Tromey
977a0c161d Constify linetables
Linetables no longer change after they are created.  This patch
applies const to them.

Note there is one hack to cast away const in mdebugread.c.  This code
allocates a linetable using 'malloc', then later copies it to the
obstack.  While this could be cleaned up, I chose not to do so because
I have no way of testing it.

Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-03-11 08:48:10 -07:00
Tom Tromey
1acc9dca42 Change linetables to be objfile-independent
This changes linetables to not add the text offset to the addresses
they contain.  I did this in a few steps, necessarily combined
together in one patch: I renamed the 'pc' member to 'm_pc', added the
appropriate accessors, and then recompiled.  Then I fixed all the
errors.  Where possible I generally chose to use the raw_pc accessor,
as it is less expensive.

Note that this patch discounts the possibility that the text section
offset might cause wraparound in the addresses in the line table.
However, this was already discounted -- in particular,
objfile_relocate1 did not re-sort the table in this scenario.  (There
was a bug open about this, but as far as I can tell this has never
happened, it's not even clear what inspired that bug.)

Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-03-11 08:47:40 -07:00
Kevin Buettner
b1ffd1124a Catch gdb_exception_error instead of gdb_exception (in many places)
As described in the previous commit for this series, I became
concerned that there might be instances in which a QUIT (due to either
a SIGINT or SIGTERM) might not cause execution to return to the top
level.  In some (though very few) instances, it is okay to not
propagate the exception for a Ctrl-C / SIGINT, but I don't think that
it is ever okay to swallow the exception caused by a SIGTERM.
Allowing that to happen would definitely be a deviation from the
current behavior in which GDB exits upon receipt of a SIGTERM.

I looked at all cases where an exception handler catches a
gdb_exception.  Handlers which did NOT need modification were those
which satisifed one or more of the following conditions:

  1) There is no call path to maybe_quit() in the try block.  I used a
     static analysis tool to help make this determination.  In
     instances where the tool didn't provide an answer of "yes, this
     call path can result in maybe_quit() being called", I reviewed it
     by hand.

  2) The catch block contains a throw for conditions that it
     doesn't want to handle; these "not handled" conditions
     must include the quit exception and the new "forced quit" exception.

  3) There was (also) a catch for gdb_exception_quit.

Any try/catch blocks not meeting the above conditions could
potentially swallow a QUIT exception.

My first thought was to add catch blocks for gdb_exception_quit and
then rethrow the exception.  But Pedro pointed out that this can be
handled without adding additional code by simply catching
gdb_exception_error instead.  That's what this patch series does.

There are some oddball cases which needed to be handled differently,
plus the extension languages, but those are handled in later patches.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=26761
Tested-by: Tom de Vries <tdevries@suse.de>
Approved-by: Pedro Alves <pedro@palves.net>
2023-02-27 16:20:39 -07:00
Joel Brobecker
213516ef31 Update copyright year range in header of all files managed by GDB
This commit is the result of running the gdb/copyright.py script,
which automated the update of the copyright year range for all
source files managed by the GDB project to be updated to include
year 2023.
2023-01-01 17:01:16 +04:00
Pedro Alves
f34652de0b internal_error: remove need to pass __FILE__/__LINE__
Currently, every internal_error call must be passed __FILE__/__LINE__
explicitly, like:

  internal_error (__FILE__, __LINE__, "foo %d", var);

The need to pass in explicit __FILE__/__LINE__ is there probably
because the function predates widespread and portable variadic macros
availability.  We can use variadic macros nowadays, and in fact, we
already use them in several places, including the related
gdb_assert_not_reached.

So this patch renames the internal_error function to something else,
and then reimplements internal_error as a variadic macro that expands
__FILE__/__LINE__ itself.

The result is that we now should call internal_error like so:

  internal_error ("foo %d", var);

Likewise for internal_warning.

The patch adjusts all calls sites.  99% of the adjustments were done
with a perl/sed script.

The non-mechanical changes are in gdbsupport/errors.h,
gdbsupport/gdb_assert.h, and gdb/gdbarch.py.

Approved-By: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Ia6f372c11550ca876829e8fd85048f4502bdcf06
2022-10-19 15:32:36 +01:00
Tom Tromey
bd2b40ac12 Change GDB to use frame_info_ptr
This changes GDB to use frame_info_ptr instead of frame_info *
The substitution was done with multiple sequential `sed` commands:

sed 's/^struct frame_info;/class frame_info_ptr;/'
sed 's/struct frame_info \*/frame_info_ptr /g' - which left some
    issues in a few files, that were manually fixed.
sed 's/\<frame_info \*/frame_info_ptr /g'
sed 's/frame_info_ptr $/frame_info_ptr/g' - used to remove whitespace
    problems.

The changed files were then manually checked and some 'sed' changes
undone, some constructors and some gets were added, according to what
made sense, and what Tromey originally did

Co-Authored-By: Bruno Larsen <blarsen@redhat.com>
Approved-by: Tom Tomey <tom@tromey.com>
2022-10-10 11:57:10 +02:00
Tom Tromey
a0cbd6505e Remove frame_id_eq
This replaces frame_id_eq with operator== and operator!=.  I wrote
this for a version of this series that I later abandoned; but since it
simplifies the code, I left this patch in.

Approved-by: Tom Tomey <tom@tromey.com>
2022-10-10 11:57:10 +02:00
Tom Tromey
4a570176b4 Change target_ops::async to accept bool
This changes the parameter of target_ops::async from int to bool.
Regression tested on x86-64 Fedora 34.
2022-07-22 11:06:51 -06:00
Felix Willgerodt
49a73ab9d3 gdb, btrace: Throw an error for empty recordings when replaying starts.
This makes record_btrace_start_replaying() more consistent, as it already
errors out e.g. on a recording with only gaps.
2022-05-17 12:41:13 +02:00
Tom Tromey
4206d69e96 Replace symbol_symtab with symbol::symtab
This turns symbol_symtab into a method on symbol.  It also replaces
symbol_set_symtab with a method.
2022-04-20 09:28:40 -06:00
Tom Tromey
6cb06a8cda Unify gdb printf functions
Now that filtered and unfiltered output can be treated identically, we
can unify the printf family of functions.  This is done under the name
"gdb_printf".  Most of this patch was written by script.
2022-03-29 12:46:24 -06:00
Simon Marchi
5b6074611e gdb: remove SYMTAB_LINETABLE macro, add getter/setter
Add a getter and a setter for a symtab's linetable.  Remove the
corresponding macro and adjust all callers.

Change-Id: I159183fc0ccd8e18ab937b3c2f09ef2244ec6e9c
2022-02-06 15:48:19 -05:00
Markus Metzger
b02b09623d gdb, btrace: rename record_btrace_enable_warn()
We use record_btrace_enable_warn() as the new-thread observer callback.
It is not used in other contexts.

Rename it to record_btrace_on_new_thread() to make its role more clear.
2022-01-27 13:31:19 +01:00
Simon Marchi
e53c95d40b gdb: use ptid_t::to_string instead of target_pid_to_str in debug statements
Same idea as 0fab795564 ("gdb: use ptid_t::to_string in infrun debug
messages"), but throughout GDB.

Change-Id: I62ba36eaef29935316d7187b9b13d7b88491acc1
2022-01-18 11:28:33 -05:00
Tom Tromey
7f762abff6 Use filtered output in btrace-related commands
This changes btrace.c and record-btrace.c to use filtered output in
the commands implemented there.
2022-01-05 11:36:33 -07:00
Joel Brobecker
4a94e36819 Automatic Copyright Year update after running gdb/copyright.py
This commit brings all the changes made by running gdb/copyright.py
as per GDB's Start of New Year Procedure.

For the avoidance of doubt, all changes in this commits were
performed by the script.
2022-01-01 19:13:23 +04:00
Tom Tromey
7514a66128 Consistently Use ui_file parameter to show callbacks
I happened to notice that one "show" callback was printing to
gdb_stdout rather than to the passed-in ui_file parameter.  I went
through all such callbacks and fixed them to consistently use the
ui_file.

Regression tested on x86-64 Fedora 34.
2021-12-29 11:08:04 -07:00
Andrew Burgess
391c90eea5 gdb: make use of SCOPE_EXIT to manage thread executing state
While working on another patch relating to how GDB manages threads
executing and resumed state, I spotted the following code in
record-btrace.c:

  executing = tp->executing ();
  set_executing (proc_target, inferior_ptid, false);

  id = null_frame_id;
  try
    {
      id = get_frame_id (get_current_frame ());
    }
  catch (const gdb_exception &except)
    {
      /* Restore the previous execution state.  */
      set_executing (proc_target, inferior_ptid, executing);

      throw;
    }

  /* Restore the previous execution state.  */
  set_executing (proc_target, inferior_ptid, executing);

  return id;

I notice that we only catch the exception so we can call
set_executing, and this is the same call to set_executing that we need
to perform in the non-exception return path.

This would be much cleaner if we could use SCOPE_EXIT to avoid the
try/catch, so lets do that.

While cleaning this up, I also applied a similar patch to
record-full.c, though there's no try/catch in that case, but using
SCOPE_EXIT makes the code safe if, in the future, we do start throwing
exceptions.

There should be no user visible changes after this commit.
2021-12-23 11:42:31 +00:00
Simon Marchi
7dca2ea7ff gdb: rename target_waitstatus_to_string to target_waitstatus::to_string
Make target_waitstatus_to_string a "to_string" method of
target_waitstatus, a bit like we have ptid_t::to_string already.  This
will save a bit of typing.

Change-Id: Id261b7a09fa9fa3c738abac131c191a6f9c13905
2021-11-22 13:57:43 -05:00
Simon Marchi
f54bdb6d27 gdb: add add_setshow_prefix_cmd
There's a common pattern to call add_basic_prefix_cmd and
add_show_prefix_cmd to add matching set and show commands.  Add the
add_setshow_prefix_cmd function to factor that out and use it at a few
places.

Change-Id: I6e9e90a30e9efb7b255bf839cac27b85d7069cfd
2021-10-28 10:44:18 -04:00
Simon Marchi
183be22290 gdb, gdbserver: make target_waitstatus safe
I stumbled on a bug caused by the fact that a code path read
target_waitstatus::value::sig (expecting it to contain a gdb_signal
value) while target_waitstatus::kind was TARGET_WAITKIND_FORKED.  This
meant that the active union field was in fact
target_waitstatus::value::related_pid, and contained a ptid.  The read
signal value was therefore garbage, and that caused GDB to crash soon
after.  Or, since that GDB was built with ubsan, this nice error
message:

    /home/simark/src/binutils-gdb/gdb/linux-nat.c:1271:12: runtime error: load of value 2686365, which is not a valid value for type 'gdb_signal'

Despite being a large-ish change, I think it would be nice to make
target_waitstatus safe against that kind of bug.  As already done
elsewhere (e.g. dynamic_prop), validate that the type of value read from
the union matches what is supposed to be the active field.

 - Make the kind and value of target_waitstatus private.
 - Make the kind initialized to TARGET_WAITKIND_IGNORE on
   target_waitstatus construction.  This is what most users appear to do
   explicitly.
 - Add setters, one for each kind.  Each setter takes as a parameter the
   data associated to that kind, if any.  This makes it impossible to
   forget to attach the associated data.
 - Add getters, one for each associated data type.  Each getter
   validates that the data type fetched by the user matches the wait
   status kind.
 - Change "integer" to "exit_status", "related_pid" to "child_ptid",
   just because that's more precise terminology.
 - Fix all users.

That last point is semi-mechanical.  There are a lot of obvious changes,
but some less obvious ones.  For example, it's not possible to set the
kind at some point and the associated data later, as some users did.
But in any case, the intent of the code should not change in this patch.

This was tested on x86-64 Linux (unix, native-gdbserver and
native-extended-gdbserver boards).  It was built-tested on x86-64
FreeBSD, NetBSD, MinGW and macOS.  The rest of the changes to native
files was done as a best effort.  If I forgot any place to update in
these files, it should be easy to fix (unless the change happens to
reveal an actual bug).

Change-Id: I0ae967df1ff6e28de78abbe3ac9b4b2ff4ad03b7
2021-10-21 16:13:56 -04:00
Andrew Burgess
611841bb1a gdb: make thread_info::executing private
Rename thread_info::executing to thread_info::m_executing, and make it
private.  Add a new get/set member functions, and convert GDB to make
use of these.

The only real change of interest in this patch is in thread.c where I
have deleted the helper function set_executing_thread, and now just
use the new set function thread_info::set_executing.  However, the old
helper function set_executing_thread included some code to reset the
thread's stop_pc, so I moved this code into the new function
thread_info::set_executing.  However, I don't believe there is
anywhere that this results in a change of behaviour, previously the
executing flag was always set true through a call to
set_executing_thread anyway.
2021-09-07 12:44:08 +01:00
Simon Marchi
1edb66d856 gdb: make thread_info::suspend private, add getters / setters
A following patch will want to take some action when a pending wait
status is set on or removed from a thread.  Add a getter and a setter on
thread_info for the pending waitstatus, so that we can add some code in
the setter later.

The thing is, the pending wait status field is in the
thread_suspend_state, along with other fields that we need to backup
before and restore after the thread does an inferior function call.
Therefore, make the thread_suspend_state member private
(thread_info::suspend becomes thread_info::m_suspend), and add getters /
setters for all of its fields:

 - pending wait status
 - stop signal
 - stop reason
 - stop pc

For the pending wait status, add the additional has_pending_waitstatus
and clear_pending_waitstatus methods.

I think this makes the thread_info interface a bit nicer, because we
now access the fields as:

  thread->stop_pc ()

rather than

  thread->suspend.stop_pc

The stop_pc field being in the `suspend` structure is an implementation
detail of thread_info that callers don't need to be aware of.

For the backup / restore of the thread_suspend_state structure, add
save_suspend_to and restore_suspend_from methods.  You might wonder why
`save_suspend_to`, as opposed to a simple getter like

  thread_suspend_state &suspend ();

I want to make it clear that this is to be used only for backing up and
restoring the suspend state, _not_ to access fields like:

  thread->suspend ()->stop_pc

Adding some getters / setters allows adding some assertions.  I find
that this helps understand how things are supposed to work.  Add:

 - When getting the pending status (pending_waitstatus method), ensure
   that there is a pending status.
 - When setting a pending status (set_pending_waitstatus method), ensure
   there is no pending status.

There is one case I found where this wasn't true - in
remote_target::process_initial_stop_replies - which needed adjustments
to respect that contract.  I think it's because
process_initial_stop_replies is kind of (ab)using the
thread_info::suspend::waitstatus to store some statuses temporarily, for
its internal use (statuses it doesn't intent on leaving pending).

process_initial_stop_replies pulls out stop replies received during the
initial connection using target_wait.  It always stores the received
event in `evthread->suspend.waitstatus`.  But it only sets
waitstatus_pending_p, if it deems the event interesting enough to leave
pending, to be reported to the core:

      if (ws.kind != TARGET_WAITKIND_STOPPED
	  || ws.value.sig != GDB_SIGNAL_0)
	evthread->suspend.waitstatus_pending_p = 1;

It later uses this flag a bit below, to choose which thread to make the
"selected" one:

      if (selected == NULL
	  && thread->suspend.waitstatus_pending_p)
	selected = thread;

And ultimately that's used if the user-visible mode is all-stop, so that
we print the stop for that interesting thread:

  /* In all-stop, we only print the status of one thread, and leave
     others with their status pending.  */
  if (!non_stop)
    {
      thread_info *thread = selected;
      if (thread == NULL)
	thread = lowest_stopped;
      if (thread == NULL)
	thread = first;

      print_one_stopped_thread (thread);
    }

But in any case (all-stop or non-stop), print_one_stopped_thread needs
to access the waitstatus value of these threads that don't have a
pending waitstatus (those that had TARGET_WAITKIND_STOPPED +
GDB_SIGNAL_0).  This doesn't work with the assertions I've
put.

So, change the code to only set the thread's wait status if it is an
interesting one that we are going to leave pending.  If the thread
stopped due to a non-interesting event (TARGET_WAITKIND_STOPPED +
GDB_SIGNAL_0), don't store it.  Adjust print_one_stopped_thread to
understand that if a thread has no pending waitstatus, it's because it
stopped with TARGET_WAITKIND_STOPPED + GDB_SIGNAL_0.

The call to set_last_target_status also uses the pending waitstatus.
However, given that the pending waitstatus for the thread may have been
cleared in print_one_stopped_thread (and that there might not even be a
pending waitstatus in the first place, as explained above), it is no
longer possible to do it at this point.  To fix that, move the call to
set_last_target_status in print_one_stopped_thread.  I think this will
preserve the existing behavior, because set_last_target_status is
currently using the current thread's wait status.  And the current
thread is the last one for which print_one_stopped_thread is called.  So
by calling set_last_target_status in print_one_stopped_thread, we'll get
the same result.  set_last_target_status will possibly be called
multiple times, but only the last call will matter.  It just means
possibly more calls to set_last_target_status, but those are cheap.

Change-Id: Iedab9653238eaf8231abcf0baa20145acc8b77a7
2021-07-12 20:46:53 -04:00
Simon Marchi
a154d838a7 gdb: add names to unwinders, add debug messages when looking for unwinder
I wrote this while debugging a problem where the expected unwinder for a
frame wasn't used.  It adds messages to show which unwinders are
considered for a frame, why they are not selected (if an exception is
thrown), and finally which unwinder is selected in the end.

To be able to show a meaningful, human-readable name for the unwinders,
add a "name" field to struct frame_unwind, and update all instances to
include a name.

Here's an example of the output:

    [frame] frame_unwind_find_by_frame: this_frame=0
    [frame] frame_unwind_try_unwinder: trying unwinder "dummy"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "dwarf2 tailcall"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "inline"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "jit"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "python"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "amd64 epilogue"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "i386 epilogue"
    [frame] frame_unwind_try_unwinder: no
    [frame] frame_unwind_try_unwinder: trying unwinder "dwarf2"
    [frame] frame_unwind_try_unwinder: yes

gdb/ChangeLog:

	* frame-unwind.h (struct frame_unwind) <name>: New.  Update
	instances everywhere to include this field.
	* frame-unwind.c (frame_unwind_try_unwinder,
	frame_unwind_find_by_frame): Add debug messages.

Change-Id: I813f17777422425f0d08b22499817b23922e8ddb
2021-06-29 12:05:03 -04:00
Simon Marchi
5e84b7eefb gdb: remove add_alias_cmd overload that accepts a string
Same idea as previous patch, but for add_alias_cmd.  Remove the overload
that accepts the target command as a string (the target command name),
leaving only the one that takes the cmd_list_element.

gdb/ChangeLog:

	* command.h (add_alias_cmd): Accept target as
	cmd_list_element.  Update callers.

Change-Id: I546311f411e9e7da9302322d6ffad4e6c56df266
2021-05-27 14:00:08 -04:00
Marco Barisione
2f822da535 gdb: generate the prefix name for prefix commands on demand
Previously, the prefixname field of struct cmd_list_element was manually
set for prefix commands.  This seems verbose and error prone as it
required every single call to functions adding prefix commands to
specify the prefix name while the same information can be easily
generated.

Historically, this was not possible as the prefix field was null for
many commands, but this was fixed in commit
3f4d92ebdf by Philippe Waroquiers, so
we can rely on the prefix field being set when generating the prefix
name.

This commit also fixes a use after free in this scenario:
* A command gets created via Python (using the gdb.Command class).
  The prefix name member is dynamically allocated.
* An alias to the new command is created. The alias's prefixname is set
  to point to the prefixname for the original command with a direct
  assignment.
* A new command with the same name as the Python command is created.
* The object for the original Python command gets freed and its
  prefixname gets freed as well.
* The alias is updated to point to the new command, but its prefixname
  is not updated so it keeps pointing to the freed one.

gdb/ChangeLog:

	* command.h (add_prefix_cmd): Remove the prefixname argument as
	it can now be generated automatically.  Update all callers.
	(add_basic_prefix_cmd): Ditto.
	(add_show_prefix_cmd): Ditto.
	(add_prefix_cmd_suppress_notification): Ditto.
	(add_abbrev_prefix_cmd): Ditto.
	* cli/cli-decode.c (add_prefix_cmd): Ditto.
	(add_basic_prefix_cmd): Ditto.
	(add_show_prefix_cmd): Ditto.
	(add_prefix_cmd_suppress_notification): Ditto.
	(add_prefix_cmd_suppress_notification): Ditto.
	(add_abbrev_prefix_cmd): Ditto.
	* cli/cli-decode.h (struct cmd_list_element): Replace the
	prefixname member variable with a method which generates the
	prefix name at runtime.  Update all code reading the prefix
	name to use the method, and remove all code setting it.
	* python/py-cmd.c (cmdpy_destroyer): Remove code to free the
	prefixname member as it's now a method.
	(cmdpy_function): Determine if the command is a prefix by
	looking at prefixlist, not prefixname.
2021-05-12 11:19:22 +01:00
Simon Marchi
c90e7d6352 gdbsupport, gdb: give names to observers
Give a name to each observer, this will help produce more meaningful
debug message.

gdbsupport/ChangeLog:

	* observable.h (class observable) <struct observer> <observer>:
	Add name parameter.
	<name>: New field.
	<attach>: Add name parameter, update all callers.

Change-Id: Ie0cc4664925215b8d2b09e026011b7803549fba0
2021-04-24 19:26:41 -04:00
Simon Marchi
02980c5645 gdb: remove push_target free functions
Same as the previous patch, but for the push_target functions.

The implementation of the move variant is moved to a new overload of
inferior::push_target.

gdb/ChangeLog:

	* target.h (push_target): Remove, update callers to use
	inferior::push_target.
	* target.c (push_target): Remove.
	* inferior.h (class inferior) <push_target>: New overload.

Change-Id: I5a95496666278b8f3965e5e8aecb76f54a97c185
2021-03-23 09:50:35 -04:00
Simon Marchi
fadf6add30 gdb: remove unpush_target free function
unpush_target unpushes the passed-in target from the current inferior's
target stack.  Calling it is therefore an implicit dependency on the
current global inferior.  Remove that function and make the callers use
the inferior::unpush_target method directly.  This sometimes allows
using the inferior from the context rather than the global current
inferior.

target_unpusher::operator() now needs to be implemented in target.c,
otherwise target.h and inferior.h both need to include each other, and
that wouldn't work.

gdb/ChangeLog:

	* target.h (unpush_target): Remove, update all callers
	to use `inferior::unpush_target` instead.
	(struct target_unpusher) <operator()>: Just declare.
	* target.c (unpush_target): Remove.
	(target_unpusher::operator()): New.

Change-Id: Ia5172dfb3f373e0a75b991885b50322ca2142a8c
2021-03-23 09:50:32 -04:00
Andrew Burgess
19cf757a87 gdb: spread a little 'const' through the target_section_table code
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.
2021-02-24 16:58:02 +00:00
Simon Marchi
85d3ad8e0b gdb: make record-btrace clear event handler in wait
For the same reason explained in the previous patch (which was for the
remote target), move clearing of the async event handler of the
record-btrace target to the wait method.

The record-btrace target already re-sets its async event handler in its
wait method, so that part doesn't need to be changed:

    /* In async mode, we need to announce further events.  */
    if (target_is_async_p ())
      record_btrace_maybe_mark_async_event (moving, no_history);

gdb/ChangeLog:

	* record-btrace.c (record_btrace_handle_async_inferior_event):
	Don't clear async event handler.
	(record_btrace_target::wait): Clear async event handler at
	beginning.

Change-Id: Ib32087a81bf94f1b884a938c8167ac8bbe09e362
2021-02-04 13:35:09 -05:00
Simon Marchi
6b36ddeb1e gdb: make async event handlers clear themselves
The `ready` flag of async event handlers is cleared by the async event
handler system right before invoking the associated callback, in
check_async_event_handlers.

This is not ideal with how the infrun subsystem consumes events: all
targets' async event handler callbacks essentially just invoke
`inferior_event_handler`, which eventually calls `fetch_inferior_event`
and `do_target_wait`.  `do_target_wait` picks an inferior at random,
and thus a target at random (it could be the target whose `ready` flag
was cleared, or not), and pulls one event from it.

So it's possible that:

- the async event handler for a target A is called
- we end up consuming an event for target B
- all threads of target B are stopped, target_async(0) is called on it,
  so its async event handler is cleared (e.g.
  record_btrace_target::async)

As a result, target A still has events to report while its async event
handler is left unmarked, so these events are not consumed.  To counter
this, at the end of their async event handler callbacks, targets check
if they still have something to report and re-mark their async event
handler (e.g. remote_async_inferior_event_handler).

The linux_nat target does not suffer from this because it doesn't use an
async event handler at the moment.  It only uses a pipe registered with
the event loop.  It is written to in the SIGCHLD handler (and in other
spots that want to get target wait method called) and read from in
the target's wait method.  So if linux_nat happened to be target A in
the example above, the pipe would just stay readable, and the event loop
would wake up again, until linux_nat's wait method is finally called and
consumes the contents of the pipe.

I think it would be nicer if targets using async_event_handler worked in
a similar way, where the flag would stay set until the target's wait
method is actually called.  As a first step towards that, this patch
moves the responsibility of clearing the ready flags of async event
handlers to the invoked callback.

All async event handler callbacks are modified to clear their ready flag
before doing anything else.  So in practice, nothing changes with this
patch.  It's only the responsibility of clearing the flag that is
shifted toward the callee.

gdb/ChangeLog:

	* async-event.h (async_event_handler_func):  Add documentation.
	* async-event.c (check_async_event_handlers): Don't clear
	async_event_handler ready flag.
	* infrun.c (infrun_async_inferior_event_handler): Clear ready
	flag.
	* record-btrace.c (record_btrace_handle_async_inferior_event):
	Likewise.
	* record-full.c (record_full_async_inferior_event_handler):
	Likewise.
	* remote-notif.c (remote_async_get_pending_events_handler):
	Likewise.
	* remote.c (remote_async_inferior_event_handler): Likewise.

Change-Id: I179ef8e99580eae642d332846fd13664dbddc0c1
2021-02-04 13:13:30 -05:00
Simon Marchi
bd497355ea gdb: remove target_ops::commit_resume implementation in record-{btrace, full}.c
The previous patch made the commit_resume implementations in the record
targets unnecessary, as the remote target's commit_resume implementation
won't commit-resume threads for which it didn't see a resume.  This
patch removes them.

gdb/ChangeLog:

	* record-btrace.c (class record_btrace_target): Remove.
	(record_btrace_target::commit_resume): Remove.
	* record-full.c (class record_full_target): Remove.
	(record_full_target::commit_resume): Remove.

Change-Id: I3a68d3d726fb09d8b7165b4edefc330d27803b27
2021-01-13 20:26:05 -05:00
Joel Brobecker
3666a04883 Update copyright year range in all GDB files
This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...

gdb/ChangeLog

        Update copyright year range in copyright header of all GDB files.
2021-01-01 12:12:21 +04:00