[6/9] gdb: parse pending breakpoint thread/task immediately

Message ID 54ed8033aaf1f220b69f8ae08ab9ba6c396fde35.1682724005.git.aburgess@redhat.com
State New
Headers
Series thread-specific breakpoints in just some inferiors |

Commit Message

Andrew Burgess April 28, 2023, 11:35 p.m. UTC
  The initial motivation for this commit was to allow thread or (in the
future) inferior specific breakpoints to only be inserted within the
appropriate inferior's program-space.  The benefit of this is that
inferiors for which the breakpoint does not apply will no longer need
to stop, and then resume, for such breakpoints.  This commit does not
make this change, but is a refactor to allow this change in a later
commit.

The problem we currently have is that when a thread-specific
breakpoint is created, the thread number is only parsed by calling
find_condition_and_thread_for_sals.  This function is only called for
non-pending breakpoints, and requires that we know the locations at
which the breakpoint will be placed (for expression checking in case
the breakpoint is also conditional).

A consequence of this is that by the time we figure out the breakpoint
is thread-specific we have already looked up locations in all program
spaces.  This feels wasteful -- if we knew the thread-id earlier then
we could reduce the work GDB does by only looking up locations within
the program space for which the breakpoint applies.

Another consequence of how find_condition_and_thread_for_sals is
called is that pending breakpoints don't currently know they are
thread-specific, nor even that they are conditional!  Additionally, by
delaying parsing the thread-id, pending breakpoints can be created for
non-existent threads, this is different to how non-pending
breakpoints are handled.

In this commit the create_breakpoint function is updated so that the
extra_string, which contains the thread/task/condition information, is
parsed immediately, even for pending breakpoints.

Obviously, the condition still can't be validated until the breakpoint
becomes non-pending, but the thread/task information can be pulled
from the extra-string, and can be validated early on, even for pending
breakpoints.

There are a couple of benefits to doing this:

1. Printing of breakpoints is more consistent now.  Consider creating
   a conditional breakpoint before this commit:

    (gdb) set breakpoint pending on
    (gdb) break pendingfunc if (0)
    Function "pendingfunc" not defined.
    Breakpoint 1 (pendingfunc if (0)) pending.
    (gdb) break main if (0)
    Breakpoint 2 at 0x401198: file /tmp/hello.c, line 18.
    (gdb) info breakpoints
    Num     Type           Disp Enb Address            What
    1       breakpoint     keep y   <PENDING>          pendingfunc if (0)
    2       breakpoint     keep y   0x0000000000401198 in main at /tmp/hello.c:18
            stop only if (0)
    (gdb)

   And after this commit:

    (gdb) set breakpoint pending on
    (gdb) break pendingfunc if (0)
    Function "pendingfunc" not defined.
    Breakpoint 1 (pendingfunc) pending.
    (gdb) break main if (0)
    Breakpoint 2 at 0x401198: file /home/andrew/tmp/hello.c, line 18.
    (gdb) info breakpoints
    Num     Type           Disp Enb Address            What
    1       breakpoint     keep y   <PENDING>          pendingfunc
            stop only if (0)
    2       breakpoint     keep y   0x0000000000401198 in main at /home/andrew/tmp/hello.c:18
            stop only if (0)
    (gdb)

   Notice that the display of the condition is now the same for the
   pending and non-pending breakpoints.

   The same is true for the thread information in thread-specific
   breakpoints, this information is displayed on its own line now
   rather than being part of the 'What' field.

2. We can check that the thread exists as soon as the pending
   breakpoint exits.  Currently there is a weird different between
   pending and non-pending breakpoints when creating a thread-specific
   breakpoint.  A pending thread-specific breakpoint only checks its
   thread when it becomes non-pending, at which point the thread the
   breakpoint was intended for might have exited.  Here's the
   behaviour before this commit:

    (gdb) set breakpoint pending on
    (gdb) break foo thread 2
    Function "foo" not defined.
    Breakpoint 2 (foo thread 2) pending.
    (gdb) c
    Continuing.
    [Thread 0x7ffff7c56700 (LWP 2948835) exited]
    Error in re-setting breakpoint 2: Unknown thread 2.
    [Inferior 1 (process 2948832) exited normally]
    (gdb)

   Notice the 'Error in re-setting breakpoint 2: Unknown thread 2.'
   line, this was triggered when the thread tried to become
   non-pending, and GDB discovers that the thread no longer exists.

   Compare that to the behaviour after this commit:

    (gdb) set breakpoint pending on
    (gdb) break foo thread 2
    Function "foo" not defined.
    Breakpoint 2 (foo) pending.
    (gdb) c
    Continuing.
    [Thread 0x7ffff7c56700 (LWP 2949243) exited]
    Thread-specific breakpoint 2 deleted - thread 2 no longer in the thread list.
    [Inferior 1 (process 2949240) exited normally]
    (gdb)

   Now the behaviour for pending breakpoints is identical to
   non-pending breakpoints, the thread specific breakpoint is removed
   as soon as the thread the breakpoint is associated with exits.

As a result of this commit the breakpoints 'extra_string' field is now
only used by bp_dprintf type breakpoints to hold the printf format and
arguments.  This string should always be empty for other breakpoint
types.  This allows me to clean up some code in
print_breakpoint_location.

In code_breakpoint::code_breakpoint I'm able to change an error case
into an assert.  This is because this error is now handled earlier in
create_breakpoint.  As a result we know that by this point, the
extra_string will always be nullptr for anything other than a
bp_dprintf style breakpoint.

The find_condition_and_thread_for_sals function is now no longer
needed, this was previously doing the delayed splitting of the extra
string into thread, task, and condition, but this is now all done in
create_breakpoint, so find_condition_and_thread_for_sals can be
deleted, and the code that calls this in
code_breakpoint::location_spec_to_sals can be removed.  With this
update this code would only ever be reached for bp_dprintf style
breakpoints, and in these cases the extra_string should not contain
anything other than format and args.

The most interesting changes are all in create_breakpoint and in the
new file break-cond-parse.c.  We have a new block of code early on in
create_breakpoint that is responsible for splitting the extra_string
into its component parts by calling create_breakpoint_parse_arg_string
a function in the new break-cond-parse.c file.  This means that some
of the later code can be simplified a little.

The new break-cond-parse.c file implements the splitting up the
extra_string and finding all the parts, as well as some self-tests for
the new function.

Finally, now we know all the details, these can be stored within the
breakpoint object if we end up creating a deferred breakpoint.
Additionally, if we are creating a deferred bp_dprintf we can parse
the extra_string to build the printf command.
---
 gdb/Makefile.in                               |   2 +
 gdb/NEWS                                      |   4 +
 gdb/break-cond-parse.c                        | 403 ++++++++++++++++++
 gdb/break-cond-parse.h                        |  47 ++
 gdb/breakpoint.c                              | 330 ++++----------
 gdb/testsuite/gdb.base/condbreak.exp          |  20 +-
 gdb/testsuite/gdb.base/pending.exp            |  23 +-
 gdb/testsuite/gdb.linespec/explicit.exp       |   4 +-
 gdb/testsuite/gdb.mi/mi-dprintf-pending.exp   |   3 +-
 .../gdb.threads/del-pending-thread-bp-lib.c   |  22 +
 .../gdb.threads/del-pending-thread-bp.c       |  85 ++++
 .../gdb.threads/del-pending-thread-bp.exp     | 108 +++++
 12 files changed, 793 insertions(+), 258 deletions(-)
 create mode 100644 gdb/break-cond-parse.c
 create mode 100644 gdb/break-cond-parse.h
 create mode 100644 gdb/testsuite/gdb.threads/del-pending-thread-bp-lib.c
 create mode 100644 gdb/testsuite/gdb.threads/del-pending-thread-bp.c
 create mode 100644 gdb/testsuite/gdb.threads/del-pending-thread-bp.exp
  

Comments

Eli Zaretskii April 29, 2023, 6:01 a.m. UTC | #1
> Cc: Andrew Burgess <aburgess@redhat.com>
> Date: Sat, 29 Apr 2023 00:35:42 +0100
> From: Andrew Burgess via Gdb-patches <gdb-patches@sourceware.org>
> 
>  gdb/Makefile.in                               |   2 +
>  gdb/NEWS                                      |   4 +
>  gdb/break-cond-parse.c                        | 403 ++++++++++++++++++
>  gdb/break-cond-parse.h                        |  47 ++
>  gdb/breakpoint.c                              | 330 ++++----------
>  gdb/testsuite/gdb.base/condbreak.exp          |  20 +-
>  gdb/testsuite/gdb.base/pending.exp            |  23 +-
>  gdb/testsuite/gdb.linespec/explicit.exp       |   4 +-
>  gdb/testsuite/gdb.mi/mi-dprintf-pending.exp   |   3 +-
>  .../gdb.threads/del-pending-thread-bp-lib.c   |  22 +
>  .../gdb.threads/del-pending-thread-bp.c       |  85 ++++
>  .../gdb.threads/del-pending-thread-bp.exp     | 108 +++++
>  12 files changed, 793 insertions(+), 258 deletions(-)
>  create mode 100644 gdb/break-cond-parse.c
>  create mode 100644 gdb/break-cond-parse.h
>  create mode 100644 gdb/testsuite/gdb.threads/del-pending-thread-bp-lib.c
>  create mode 100644 gdb/testsuite/gdb.threads/del-pending-thread-bp.c
>  create mode 100644 gdb/testsuite/gdb.threads/del-pending-thread-bp.exp

The NEWS part is OK, thanks.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
  

Patch

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 40497541880..a0f8be91bc9 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1025,6 +1025,7 @@  COMMON_SFILES = \
 	break-catch-sig.c \
 	break-catch-syscall.c \
 	break-catch-throw.c \
+	break-cond-parse.c \
 	breakpoint.c \
 	bt-utils.c \
 	btrace.c \
@@ -1290,6 +1291,7 @@  HFILES_NO_SRCDIR = \
 	bfd-target.h \
 	bfin-tdep.h \
 	block.h \
+	break-cond-parse.h \
 	breakpoint.h \
 	bsd-kvm.h \
 	bsd-uthread.h \
diff --git a/gdb/NEWS b/gdb/NEWS
index e3c095de09e..8a7d4b25830 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -67,6 +67,10 @@ 
     break foo thread 1 task 1
     watch var thread 2 task 3
 
+* For breakpoints that are created in the 'pending' state, any
+  'thread' or 'task' keywords are parsed at the time the breakpoint is
+  created, rather than at the time the breakpoint becomes non-pending.
+
 * New commands
 
 maintenance print record-instruction [ N ]
diff --git a/gdb/break-cond-parse.c b/gdb/break-cond-parse.c
new file mode 100644
index 00000000000..e8da24d2643
--- /dev/null
+++ b/gdb/break-cond-parse.c
@@ -0,0 +1,403 @@ 
+/* Copyright (C) 2023 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+#include "gdbsupport/gdb_assert.h"
+#include "gdbsupport/selftest.h"
+#include "test-target.h"
+#include "scoped-mock-context.h"
+#include "break-cond-parse.h"
+#include "tid-parse.h"
+#include "ada-lang.h"
+
+/* When parsing tokens from a string, which direction are we parsing?
+
+   Given the following string and pointer 'ptr':
+
+     ABC DEF GHI JKL
+            ^
+           ptr
+
+   Parsing 'forward' will return the token 'GHI' and update 'ptr' to point
+   between GHI and JKL.  Parsing 'backward' will return the token 'DEF' and
+   update 'ptr' to point between ABC and DEF.
+*/
+
+enum class parse_direction
+{
+  /* Parse the next token forwards.  */
+  forward,
+
+  /* Parse the previous token backwards.  */
+  backward
+};
+
+struct token
+{
+  /* Create a new token.  START points to the first character of the new
+     token, while END points at the last character of the new token.
+
+     Neither START or END can be nullptr, and both START and END must point
+     into the same C style string (i.e. there should be no null character
+     between START and END).  END must be equal to, or greater than START,
+     that is, it is not possible to create a zero length token.  */
+
+  token (const char *start, const char *end)
+    : m_start (start),
+      m_end (end)
+  {
+    gdb_assert (m_end >= m_start);
+    gdb_assert (m_start + strlen (m_start) > m_end);
+  }
+
+  /* Return a pointer to the first character of this token.  */
+  const char *start () const
+  {
+    return m_start;
+  }
+
+  /* Return a pointer to the last character of this token.  */
+  const char *end () const
+  {
+    return m_end;
+  }
+
+  /* Return the length of the token.  */
+  size_t length () const
+  {
+    return m_end - m_start + 1;
+  }
+
+  /* Return true if this token matches STR.  If this token is shorter than
+     STR then only a partial match is performed and true will be returned
+     if the token length sub-string matches.  Otherwise, return false.  */
+  bool matches (const char *str) const
+  {
+    return strncmp (m_start, str, length ()) == 0;
+  }
+
+private:
+  /* The first character of this token.  */
+  const char *m_start;
+
+  /* The last character of this token.  */
+  const char *m_end;
+};
+
+/* Find the next token in DIRECTION from *CURR.  */
+
+static token
+find_next_token (const char **curr, parse_direction direction)
+{
+  const char *tok_start, *tok_end;
+
+  if (direction == parse_direction::forward)
+    {
+      *curr = skip_spaces (*curr);
+      tok_start = *curr;
+      *curr = skip_to_space (*curr);
+      tok_end = *curr - 1;
+    }
+  else
+    {
+      gdb_assert (direction == parse_direction::backward);
+
+      while (isspace (**curr))
+	--(*curr);
+
+      tok_end = *curr;
+
+      while (!isspace (**curr))
+	--(*curr);
+
+      tok_start = (*curr) + 1;
+    }
+
+  return token (tok_start, tok_end);
+}
+
+/* See break-cond-parse.h.  */
+
+void
+create_breakpoint_parse_arg_string
+  (const char *tok, gdb::unique_xmalloc_ptr<char> *cond_string,
+   int *thread, int *task, gdb::unique_xmalloc_ptr<char> *rest, bool *force)
+{
+  /* Set up the defaults.  */
+  cond_string->reset ();
+  rest->reset ();
+  *thread = -1;
+  *task = -1;
+  *force = false;
+
+  if (tok == nullptr)
+    return;
+
+  const char *cond_start = nullptr;
+  const char *cond_end = nullptr;
+  parse_direction direction = parse_direction::forward;
+  while (*tok != '\0')
+    {
+      /* Find the next token.  If moving backward and this token starts at
+	 the same location as the condition then we must have found the
+	 other end of the condition string -- we're done.  */
+      token t = find_next_token (&tok, direction);
+      if (direction == parse_direction::backward && t.start () <= cond_start)
+	{
+	  cond_end = t.end () + 1;
+	  break;
+	}
+
+      /* We only have a single flag option to check for.  All the other
+	 options take a value so require an additional token to be found.  */
+      if (t.length () > 0 && t.matches ("-force-condition"))
+	{
+	  *force = true;
+	  continue;
+	}
+
+      /* Maybe the first token was the last token in the string.  If this
+	 is the case then we definitely can't try to extract a value
+	 token.  This also means that the token T is meaningless.  Reset
+	 TOK to point at the start of the unknown content and break out of
+	 the loop.  We'll record the unknown part of the string outside of
+	 the scanning loop (below).  */
+      if (direction == parse_direction::forward && *tok == '\0')
+	{
+	  tok = t.start ();
+	  break;
+	}
+
+      /* As before, find the next token and, if we are scanning backwards,
+	 check that we have not reached the start of the condition string.  */
+      token v = find_next_token (&tok, direction);
+      if (direction == parse_direction::backward && v.start () <= cond_start)
+	{
+	  /* Use token T here as that must also be part of the condition
+	     string.  */
+	  cond_end = t.end () + 1;
+	  break;
+	}
+
+      /* When moving backward we will first parse the value token then the
+	 keyword token, so swap them now.  */
+      if (direction == parse_direction::backward)
+	std::swap (t, v);
+
+      /* Check for valid option in token T.  If we find a valid option then
+	 parse the value from the token V.  Except for 'if', that's handled
+	 differently.
+
+         For the 'if' token we need to capture the entire condition
+         string, so record the start of the condition string and then
+         start scanning backwards looking for the end of the condition
+         string.  */
+      if (direction == parse_direction::forward && t.length () > 0
+	  && t.matches ("if"))
+	{
+	  cond_start = v.start ();
+	  tok = tok + strlen (tok);
+	  gdb_assert (*tok == '\0');
+	  --tok;
+	  direction = parse_direction::backward;
+	  continue;
+	}
+      else if (t.length () > 0 && t.matches ("thread"))
+	{
+	  const char *tmptok;
+	  struct thread_info *thr;
+
+	  if (*thread != -1)
+	    error(_("You can specify only one thread."));
+
+	  if (*task != -1)
+	    error (_("You can specify only one of thread or task."));
+
+	  thr = parse_thread_id (v.start (), &tmptok);
+	  const char *expected_end = skip_spaces (v.end () + 1);
+	  if (tmptok != expected_end)
+	    error (_("Junk after thread keyword."));
+	  *thread = thr->global_num;
+	}
+      else if (t.length () > 0 && t.matches ("task"))
+	{
+	  char *tmptok;
+
+	  if (*task != -1)
+	    error(_("You can specify only one task."));
+
+	  if (*thread != -1)
+	    error (_("You can specify only one of thread or task."));
+
+	  *task = strtol (v.start (), &tmptok, 0);
+	  const char *expected_end = v.end () + 1;
+	  if (tmptok != expected_end)
+	    error (_("Junk after task keyword."));
+	  if (!valid_task_id (*task))
+	    error (_("Unknown task %d."), *task);
+	}
+      else
+	{
+	  /* An unknown token.  If we are scanning forward then reset TOK
+	     to point at the start of the unknown content, we record this
+	     outside of the scanning loop (below).
+
+	     If we are scanning backward then unknown content is assumed to
+	     be the other end of the condition string, obviously, this is
+	     just a heuristic, we could be looking at a mistyped command
+	     line, but this will be spotted when the condition is
+	     eventually evaluated.
+
+	     Either way, no more scanning is required after this.  */
+	  if (direction == parse_direction::forward)
+	    tok = t.start ();
+	  else
+	    {
+	      gdb_assert (direction == parse_direction::backward);
+	      cond_end = v.end () + 1;
+	    }
+	  break;
+	}
+    }
+
+  if (cond_start != nullptr)
+    {
+      /* If we found the start of a condition string then we should have
+	 switched to backward scan mode, and found the end of the condition
+	 string.  Capture the whole condition string into COND_STRING now.  */
+      gdb_assert (direction == parse_direction::backward);
+      gdb_assert (cond_end != nullptr);
+      cond_string->reset (savestring (cond_start, cond_end - cond_start));
+    }
+  else if (*tok != '\0')
+    {
+      /* If we didn't have a condition start pointer then we should still
+	 be in forward scanning mode.  If we didn't reach the end of the
+	 input string (TOK is not at the null character) then the rest of
+	 the input string is garbage that we didn't understand.
+
+	 Record the unknown content into REST.  The caller of this function
+	 will report this as an error later on.  We could report the error
+	 here, but we prefer to allow the caller to run other checks, and
+	 prioritise other errors before reporting this problem.  */
+      gdb_assert (direction == parse_direction::forward);
+      rest->reset (savestring (tok, strlen (tok)));
+    }
+}
+
+#if GDB_SELF_TEST
+
+namespace selftests {
+
+/* Run a single test of the create_breakpoint_parse_arg_string function.
+   INPUT is passed to create_breakpoint_parse_arg_string while all other
+   arguments are the expected output from
+   create_breakpoint_parse_arg_string.  */
+
+static void
+test (const char *input, const char *condition, int thread = -1,
+      int task = -1, bool force = false, const char *rest = nullptr)
+{
+  gdb::unique_xmalloc_ptr<char> extracted_condition;
+  gdb::unique_xmalloc_ptr<char> extracted_rest;
+  int extracted_thread, extracted_task;
+  bool extracted_force_condition;
+  std::string exception_msg;
+
+  try
+    {
+      create_breakpoint_parse_arg_string (input, &extracted_condition,
+					  &extracted_thread,
+					  &extracted_task, &extracted_rest,
+					  &extracted_force_condition);
+    }
+  catch (const gdb_exception_error &ex)
+    {
+      string_file buf;
+
+      exception_print (&buf, ex);
+      exception_msg = buf.release ();
+    }
+
+  if ((condition == nullptr) != (extracted_condition.get () == nullptr)
+      || (condition != nullptr
+	  && strcmp (condition, extracted_condition.get ()) != 0)
+      || (rest == nullptr) != (extracted_rest.get () == nullptr)
+      || (rest != nullptr && strcmp (rest, extracted_rest.get ()) != 0)
+      || thread != extracted_thread
+      || task != extracted_task
+      || force != extracted_force_condition
+      || !exception_msg.empty ())
+    {
+      if (run_verbose ())
+	{
+	  debug_printf ("input: '%s'\n", input);
+	  debug_printf ("condition: '%s'\n", extracted_condition.get ());
+	  debug_printf ("rest: '%s'\n", extracted_rest.get ());
+	  debug_printf ("thread: %d\n", extracted_thread);
+	  debug_printf ("task: %d\n", extracted_task);
+	  debug_printf ("forced: %s\n",
+			extracted_force_condition ? "true" : "false");
+	  debug_printf ("exception: '%s'\n", exception_msg.c_str ());
+	}
+
+      /* Report the failure.  */
+      SELF_CHECK (false);
+    }
+}
+
+/* Test the create_breakpoint_parse_arg_string function.  Just wraps
+   multiple calls to the test function above.  */
+
+static void
+create_breakpoint_parse_arg_string_tests (void)
+{
+  gdbarch *arch = current_inferior ()->gdbarch;
+  scoped_restore_current_pspace_and_thread restore;
+  scoped_mock_context<test_target_ops> mock_target (arch);
+
+  int global_thread_num = mock_target.mock_thread.global_num;
+
+  test ("  if blah  ", "blah");
+  test (" if blah thread 1", "blah", global_thread_num);
+  test (" if blah thread 1  ", "blah", global_thread_num);
+  test ("thread 1 woof", nullptr, global_thread_num, -1, false, "woof");
+  test ("thread 1 X", nullptr, global_thread_num, -1, false, "X");
+  test (" if blah thread 1 -force-condition", "blah", global_thread_num,
+	-1, true);
+  test (" -force-condition if blah thread 1", "blah", global_thread_num,
+	-1, true);
+  test (" -force-condition if blah thread 1  ", "blah", global_thread_num,
+	-1, true);
+  test ("thread 1 -force-condition if blah", "blah", global_thread_num,
+	-1, true);
+  test ("if (A::outer::func ())", "(A::outer::func ())");
+}
+
+} // namespace selftests
+#endif /* GDB_SELF_TEST */
+
+void _initialize_break_cond_parse ();
+void
+_initialize_break_cond_parse ()
+{
+#if GDB_SELF_TEST
+  selftests::register_test
+    ("create_breakpoint_parse_arg_string",
+     selftests::create_breakpoint_parse_arg_string_tests);
+#endif
+}
diff --git a/gdb/break-cond-parse.h b/gdb/break-cond-parse.h
new file mode 100644
index 00000000000..ec62b88ea92
--- /dev/null
+++ b/gdb/break-cond-parse.h
@@ -0,0 +1,47 @@ 
+/* Copyright (C) 2023 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#if !defined (BREAK_COND_PARSE_H)
+#define BREAK_COND_PARSE_H 1
+
+/* Given TOK, a string possibly containing a condition, thread, task and
+   force-condition flag, as accepted by the 'break' command, extract the
+   condition string, thread and task numbers, and the force_condition flag,
+   then set *COND_STRING, *THREAD, *TASK, and *FORCE.
+
+   As TOK is parsed, if an unknown keyword is encountered before the 'if'
+   keyword then everything starting from the unknown keyword is placed into
+   *REST.
+
+   Both *COND and *REST are initialized to nullptr.  If no 'if' keyword is
+   found then *COND will be returned as nullptr.  If no unknown content is
+   found then *REST is returned as nullptr.
+
+   If no thread is found, *THREAD is set to -1.  If no task is found, *TASK
+   is set to -1.  If the -force-condition flag is not found then *FORCE is
+   set to false.
+
+   Due to the free-form nature that the string TOK might take (a 'thread'
+   keyword can appear before or after an 'if' condition) then we end up
+   having to check for keywords from both the start of TOK and the end of
+   TOK.  */
+
+extern void create_breakpoint_parse_arg_string
+  (const char *tok, gdb::unique_xmalloc_ptr<char> *cond_string,
+   int *thread, int *task, gdb::unique_xmalloc_ptr<char> *rest, bool *force);
+
+#endif
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 3e52234e72d..483777ce19b 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -68,6 +68,7 @@ 
 #include "tid-parse.h"
 #include "cli/cli-style.h"
 #include "cli/cli-decode.h"
+#include "break-cond-parse.h"
 
 /* readline include files */
 #include "readline/tilde.h"
@@ -6212,20 +6213,7 @@  print_breakpoint_location (const breakpoint *b,
       uiout->field_stream ("at", stb);
     }
   else
-    {
-      uiout->field_string ("pending", b->locspec->to_string ());
-      /* If extra_string is available, it could be holding a condition
-	 or dprintf arguments.  In either case, make sure it is printed,
-	 too, but only for non-MI streams.  */
-      if (!uiout->is_mi_like_p () && b->extra_string != NULL)
-	{
-	  if (b->type == bp_dprintf)
-	    uiout->text (",");
-	  else
-	    uiout->text (" ");
-	  uiout->text (b->extra_string.get ());
-	}
-    }
+    uiout->field_string ("pending", b->locspec->to_string ());
 
   if (loc && is_breakpoint (b)
       && breakpoint_condition_evaluation_mode () == condition_evaluation_target
@@ -8552,8 +8540,8 @@  code_breakpoint::code_breakpoint (struct gdbarch *gdbarch_,
       gdb_assert (extra_string != nullptr);
       update_dprintf_command_list (this);
     }
-  else if (extra_string != nullptr)
-    error (_("Garbage '%s' at end of command"), extra_string.get ());
+  else
+    gdb_assert (extra_string == nullptr);
 
   /* The order of the locations is now stable.  Set the location
      condition using the location's number.  */
@@ -8780,160 +8768,6 @@  check_fast_tracepoint_sals (struct gdbarch *gdbarch,
     }
 }
 
-/* Given TOK, a string specification of condition and thread, as
-   accepted by the 'break' command, extract the condition
-   string and thread number and set *COND_STRING and *THREAD.
-   PC identifies the context at which the condition should be parsed.
-   If no condition is found, *COND_STRING is set to NULL.
-   If no thread is found, *THREAD is set to -1.  */
-
-static void
-find_condition_and_thread (const char *tok, CORE_ADDR pc,
-			   gdb::unique_xmalloc_ptr<char> *cond_string,
-			   int *thread, int *task,
-			   gdb::unique_xmalloc_ptr<char> *rest)
-{
-  cond_string->reset ();
-  *thread = -1;
-  *task = -1;
-  rest->reset ();
-  bool force = false;
-
-  while (tok && *tok)
-    {
-      const char *end_tok;
-      int toklen;
-      const char *cond_start = NULL;
-      const char *cond_end = NULL;
-
-      tok = skip_spaces (tok);
-
-      if ((*tok == '"' || *tok == ',') && rest)
-	{
-	  rest->reset (savestring (tok, strlen (tok)));
-	  return;
-	}
-
-      end_tok = skip_to_space (tok);
-
-      toklen = end_tok - tok;
-
-      if (toklen >= 1 && strncmp (tok, "if", toklen) == 0)
-	{
-	  tok = cond_start = end_tok + 1;
-	  try
-	    {
-	      parse_exp_1 (&tok, pc, block_for_pc (pc), 0);
-	    }
-	  catch (const gdb_exception_error &)
-	    {
-	      if (!force)
-		throw;
-	      else
-		tok = tok + strlen (tok);
-	    }
-	  cond_end = tok;
-	  cond_string->reset (savestring (cond_start, cond_end - cond_start));
-	}
-      else if (toklen >= 1 && strncmp (tok, "-force-condition", toklen) == 0)
-	{
-	  tok = tok + toklen;
-	  force = true;
-	}
-      else if (toklen >= 1 && strncmp (tok, "thread", toklen) == 0)
-	{
-	  const char *tmptok;
-	  struct thread_info *thr;
-
-	  if (*thread != -1)
-	    error(_("You can specify only one thread."));
-
-	  if (*task != -1)
-	    error (_("You can specify only one of thread or task."));
-
-	  tok = end_tok + 1;
-	  thr = parse_thread_id (tok, &tmptok);
-	  if (tok == tmptok)
-	    error (_("Junk after thread keyword."));
-	  *thread = thr->global_num;
-	  tok = tmptok;
-	}
-      else if (toklen >= 1 && strncmp (tok, "task", toklen) == 0)
-	{
-	  char *tmptok;
-
-	  if (*task != -1)
-	    error(_("You can specify only one task."));
-
-	  if (*thread != -1)
-	    error (_("You can specify only one of thread or task."));
-
-	  tok = end_tok + 1;
-	  *task = strtol (tok, &tmptok, 0);
-	  if (tok == tmptok)
-	    error (_("Junk after task keyword."));
-	  if (!valid_task_id (*task))
-	    error (_("Unknown task %d."), *task);
-	  tok = tmptok;
-	}
-      else if (rest)
-	{
-	  rest->reset (savestring (tok, strlen (tok)));
-	  return;
-	}
-      else
-	error (_("Junk at end of arguments."));
-    }
-}
-
-/* Call 'find_condition_and_thread' for each sal in SALS until a parse
-   succeeds.  The parsed values are written to COND_STRING, THREAD,
-   TASK, and REST.  See the comment of 'find_condition_and_thread'
-   for the description of these parameters and INPUT.  */
-
-static void
-find_condition_and_thread_for_sals (const std::vector<symtab_and_line> &sals,
-				    const char *input,
-				    gdb::unique_xmalloc_ptr<char> *cond_string,
-				    int *thread, int *task,
-				    gdb::unique_xmalloc_ptr<char> *rest)
-{
-  int num_failures = 0;
-  for (auto &sal : sals)
-    {
-      gdb::unique_xmalloc_ptr<char> cond;
-      int thread_id = -1;
-      int task_id = -1;
-      gdb::unique_xmalloc_ptr<char> remaining;
-
-      /* Here we want to parse 'arg' to separate condition from thread
-	 number.  But because parsing happens in a context and the
-	 contexts of sals might be different, try each until there is
-	 success.  Finding one successful parse is sufficient for our
-	 goal.  When setting the breakpoint we'll re-parse the
-	 condition in the context of each sal.  */
-      try
-	{
-	  find_condition_and_thread (input, sal.pc, &cond, &thread_id,
-				     &task_id, &remaining);
-	  *cond_string = std::move (cond);
-	  /* At most one of thread or task can be set.  */
-	  gdb_assert (thread_id == -1 || task_id == -1);
-	  *thread = thread_id;
-	  *task = task_id;
-	  *rest = std::move (remaining);
-	  break;
-	}
-      catch (const gdb_exception_error &e)
-	{
-	  num_failures++;
-	  /* If no sal remains, do not continue.  */
-	  if (num_failures == sals.size ())
-	    throw;
-	}
-    }
-}
-
 /* Decode a static tracepoint marker spec.  */
 
 static std::vector<symtab_and_line>
@@ -9044,6 +8878,44 @@  create_breakpoint (struct gdbarch *gdbarch,
 	      || (type_wanted != bp_dprintf
 		  && (extra_string == nullptr || parse_extra)));
 
+  /* Will hold either copies of the similarly named function argument, or
+     will hold a modified version of the function argument, depending on
+     the value of PARSE_EXTRA.  */
+  gdb::unique_xmalloc_ptr<char> cond_string_copy;
+  gdb::unique_xmalloc_ptr<char> extra_string_copy;
+
+  if (parse_extra)
+    {
+      /* Parse EXTRA_STRING splitting the parts out.  */
+      create_breakpoint_parse_arg_string (extra_string, &cond_string_copy,
+					  &thread, &task, &extra_string_copy,
+					  &force_condition);
+
+      /* We could check that EXTRA_STRING_COPY is empty at this point -- it
+	 should be, as we only get here for things that are not bp_dprintf,
+	 however, we prefer to give the location spec parser a chance to
+	 run first, this means the user will get errors about invalid
+	 location spec instead of an error about garbage at the end of the
+	 command line.
+
+	 We still do the EXTRA_STRING_COPY is empty check, just later in
+	 this function.  */
+
+      gdb_assert (thread == -1 || thread > 0);
+      gdb_assert (task == -1 || task > 0);
+    }
+  else
+    {
+      if (cond_string != nullptr)
+	cond_string_copy.reset (xstrdup (cond_string));
+      if (extra_string != nullptr)
+	extra_string_copy.reset (xstrdup (extra_string));
+    }
+
+  /* Clear these.  Updated values are now held in the *_copy locals.  */
+  cond_string = nullptr;
+  extra_string = nullptr;
+
   try
     {
       ops->create_sals_from_location_spec (locspec, &canonical);
@@ -9079,6 +8951,13 @@  create_breakpoint (struct gdbarch *gdbarch,
 	throw;
     }
 
+  /* The only bp_dprintf should have anything in EXTRA_STRING_COPY by this
+     point.  For all other breakpoints this indicates an error.  We could
+     place this check earlier in the function, but we prefer to see errors
+     from the location spec parser before we see this error message.  */
+  if (type_wanted != bp_dprintf && extra_string_copy.get () != nullptr)
+    error (_("Garbage '%s' at end of command"), extra_string_copy.get ());
+
   if (!pending && canonical.lsals.empty ())
     return 0;
 
@@ -9102,62 +8981,31 @@  create_breakpoint (struct gdbarch *gdbarch,
      breakpoint.  */
   if (!pending)
     {
-      gdb::unique_xmalloc_ptr<char> cond_string_copy;
-      gdb::unique_xmalloc_ptr<char> extra_string_copy;
-
-      if (parse_extra)
+      /* Check the validity of the condition.  We should error out if the
+	 condition is invalid at all of the locations and if it is not
+	 forced.  In the PARSE_EXTRA case above, this check is done when
+	 parsing the EXTRA_STRING.  */
+      if (cond_string_copy.get () != nullptr && !force_condition)
 	{
-	  gdb_assert (type_wanted != bp_dprintf);
-
-	  gdb::unique_xmalloc_ptr<char> rest;
-	  gdb::unique_xmalloc_ptr<char> cond;
-
+	  int num_failures = 0;
 	  const linespec_sals &lsal = canonical.lsals[0];
-
-	  find_condition_and_thread_for_sals (lsal.sals, extra_string,
-					      &cond, &thread, &task, &rest);
-
-	  if (rest.get () != nullptr && *(rest.get ()) != '\0')
-	    error (_("Garbage '%s' at end of command"), rest.get ());
-
-	  cond_string_copy = std::move (cond);
-	  extra_string_copy = std::move (rest);
-	}
-      else
-	{
-	  /* Check the validity of the condition.  We should error out
-	     if the condition is invalid at all of the locations and
-	     if it is not forced.  In the PARSE_EXTRA case above, this
-	     check is done when parsing the EXTRA_STRING.  */
-	  if (cond_string != nullptr && !force_condition)
+	  for (const auto &sal : lsal.sals)
 	    {
-	      int num_failures = 0;
-	      const linespec_sals &lsal = canonical.lsals[0];
-	      for (const auto &sal : lsal.sals)
+	      const char *cond = cond_string_copy.get ();
+	      try
 		{
-		  const char *cond = cond_string;
-		  try
-		    {
-		      parse_exp_1 (&cond, sal.pc, block_for_pc (sal.pc), 0);
-		      /* One success is sufficient to keep going.  */
-		      break;
-		    }
-		  catch (const gdb_exception_error &)
-		    {
-		      num_failures++;
-		      /* If this is the last sal, error out.  */
-		      if (num_failures == lsal.sals.size ())
-			throw;
-		    }
+		  parse_exp_1 (&cond, sal.pc, block_for_pc (sal.pc), 0);
+		  /* One success is sufficient to keep going.  */
+		  break;
+		}
+	      catch (const gdb_exception_error &)
+		{
+		  num_failures++;
+		  /* If this is the last sal, error out.  */
+		  if (num_failures == lsal.sals.size ())
+		    throw;
 		}
 	    }
-
-	  /* Create a private copy of condition string.  */
-	  if (cond_string)
-	    cond_string_copy.reset (xstrdup (cond_string));
-	  /* Create a private copy of any extra string.  */
-	  if (extra_string)
-	    extra_string_copy.reset (xstrdup (extra_string));
 	}
 
       ops->create_breakpoints_sal (gdbarch, &canonical,
@@ -9174,21 +9022,15 @@  create_breakpoint (struct gdbarch *gdbarch,
 								 type_wanted);
       b->locspec = locspec->clone ();
 
-      if (parse_extra)
-	b->cond_string = NULL;
-      else
-	{
-	  /* Create a private copy of condition string.  */
-	  b->cond_string.reset (cond_string != NULL
-				? xstrdup (cond_string)
-				: NULL);
-	  b->thread = thread;
-	}
+      /* Create a private copy of condition string.  */
+      b->cond_string = std::move (cond_string_copy);
+
+      b->thread = thread;
+      b->task = task;
 
       /* Create a private copy of any extra string.  */
-      b->extra_string.reset (extra_string != NULL
-			     ? xstrdup (extra_string)
-			     : NULL);
+      b->extra_string = std::move (extra_string_copy);
+
       b->ignore_count = ignore_count;
       b->disposition = tempflag ? disp_del : disp_donttouch;
       b->condition_not_parsed = 1;
@@ -9197,9 +9039,12 @@  create_breakpoint (struct gdbarch *gdbarch,
 	   && type_wanted != bp_hardware_breakpoint) || thread != -1)
 	b->pspace = current_program_space;
 
+      if (type_wanted == bp_dprintf)
+	update_dprintf_command_list (b.get ());
+
       install_breakpoint (internal, std::move (b), 0);
     }
-  
+
   if (canonical.lsals.size () > 1)
     {
       warning (_("Multiple breakpoints were set.\nUse the "
@@ -12915,23 +12760,6 @@  code_breakpoint::location_spec_to_sals (location_spec *locspec,
     {
       for (auto &sal : sals)
 	resolve_sal_pc (&sal);
-      if (condition_not_parsed && extra_string != NULL)
-	{
-	  gdb::unique_xmalloc_ptr<char> local_cond, local_extra;
-	  int local_thread, local_task;
-
-	  find_condition_and_thread_for_sals (sals, extra_string.get (),
-					      &local_cond, &local_thread,
-					      &local_task, &local_extra);
-	  gdb_assert (cond_string == nullptr);
-	  if (local_cond != nullptr)
-	    cond_string = std::move (local_cond);
-	  thread = local_thread;
-	  task = local_task;
-	  if (local_extra != nullptr)
-	    extra_string = std::move (local_extra);
-	  condition_not_parsed = 0;
-	}
 
       if (type == bp_static_tracepoint)
 	sals[0] = update_static_tracepoint (this, sals[0]);
diff --git a/gdb/testsuite/gdb.base/condbreak.exp b/gdb/testsuite/gdb.base/condbreak.exp
index a5b2a28701b..50ae82c3f32 100644
--- a/gdb/testsuite/gdb.base/condbreak.exp
+++ b/gdb/testsuite/gdb.base/condbreak.exp
@@ -179,6 +179,10 @@  gdb_test "break -q main if (1==1) thread 999" \
     "Unknown thread 999\\."
 gdb_test "break -q main thread 999 if (1==1)" \
     "Unknown thread 999\\."
+gdb_test "break -q main if (1==1) thread 999 -force-condition" \
+    "Unknown thread 999\\."
+gdb_test "break -q main thread 999 if (1==1) -force-condition" \
+    "Unknown thread 999\\."
 
 # Verify that both if and thread can be distinguished from a breakpoint
 # address expression.
@@ -186,20 +190,34 @@  gdb_test "break *main if (1==1) thread 999" \
     "Unknown thread 999\\."
 gdb_test "break *main thread 999 if (1==1)" \
     "Unknown thread 999\\."
+gdb_test "break *main if (1==1) thread 999 -force-condition" \
+    "Unknown thread 999\\."
+gdb_test "break *main thread 999 if (1==1) -force-condition" \
+    "Unknown thread 999\\."
 
 # Similarly for task.
 gdb_test "break *main if (1==1) task 999" \
     "Unknown task 999\\."
 gdb_test "break *main task 999 if (1==1)" \
     "Unknown task 999\\."
+gdb_test "break *main if (1==1) task 999 -force-condition" \
+    "Unknown task 999\\."
+gdb_test "break *main task 999 if (1==1) -force-condition" \
+    "Unknown task 999\\."
 
-# GDB accepts abbreviations for "thread" and "task".
+# GDB accepts abbreviations for "thread" and "task" and "-force-condition"
 gdb_test "break *main if (1==1) t 999" \
     "Unknown thread 999\\."
 gdb_test "break *main if (1==1) th 999" \
     "Unknown thread 999\\."
 gdb_test "break *main if (1==1) ta 999" \
     "Unknown task 999\\."
+gdb_test "break *main if (1==1) t 999 -force" \
+    "Unknown thread 999\\."
+gdb_test "break *main if (1==1) th 999 -force" \
+    "Unknown thread 999\\."
+gdb_test "break *main if (1==1) ta 999 -force" \
+    "Unknown task 999\\."
 
 set test "run until breakpoint at marker3"
 gdb_test_multiple "continue" $test {
diff --git a/gdb/testsuite/gdb.base/pending.exp b/gdb/testsuite/gdb.base/pending.exp
index d7d3735000a..645f63bdb16 100644
--- a/gdb/testsuite/gdb.base/pending.exp
+++ b/gdb/testsuite/gdb.base/pending.exp
@@ -170,7 +170,8 @@  gdb_test "info break" \
 \[\t \]+stop only if k == 1.*
 \[\t \]+print k.*
 \[0-9\]+\[\t \]+breakpoint     keep y.* in main at .*$srcfile:$mainline.*
-\[0-9\]+\[\t \]+breakpoint     keep y.*PENDING.*pendshr.c:$bp2_loc if x > 3.*" \
+\[0-9\]+\[\t \]+breakpoint     keep y.*PENDING.*pendshr.c:$bp2_loc.*
+\\s+stop only if x > 3.*" \
 "multiple pending breakpoints"
 
 
@@ -195,8 +196,10 @@  gdb_test "info break" \
 \[\t \]+stop only if k == 1.*
 \[\t \]+print k.*
 \[0-9\]+\[\t \]+breakpoint     keep y.* in main at .*$srcfile:$mainline.*
-\[0-9\]+\[\t \]+breakpoint     keep y.*PENDING.*pendshr.c:$bp2_loc if x > 3.*
-\[0-9\]+\[\t \]+breakpoint     keep y.*PENDING.*pendshr.c:$bp3_loc.*ignore next 2 hits.*" \
+\[0-9\]+\[\t \]+breakpoint     keep y.*PENDING.*pendshr.c:$bp2_loc.*
+\\s+stop only if x > 3.*
+\[0-9\]+\[\t \]+breakpoint     keep y.*PENDING.*pendshr.c:$bp3_loc.*
+\\s+ignore next 2 hits.*" \
 "multiple pending breakpoints 2"
 
 #
@@ -267,3 +270,17 @@  gdb_test "info break" \
 \[0-9\]+\[\t \]+breakpoint     keep y.* in main at .*$srcfile:$mainline.*
 \[0-9\]+\[\t \]+breakpoint     keep y.*PENDING.*imaginary.*" \
 "verify pending breakpoint after restart"
+
+# Test GDB's parsing of pending breakpoint thread and condition.
+
+gdb_test_no_output "set breakpoint pending on"
+gdb_test "break foo if (unknown_var && another_unknown_var) thread 1" \
+    "Breakpoint $decimal \\(foo\\) pending\\."
+set bpnum [get_integer_valueof "\$bpnum" "*INVALID" \
+	       "get number for foo breakpoint"]
+gdb_test "info breakpoints $bpnum" \
+    [multi_line \
+	 "$bpnum\\s+breakpoint\\s+keep\\s+y\\s+<PENDING>\\s+foo" \
+	 "\\s+stop only if \\(unknown_var && another_unknown_var\\)" \
+	 "\\s+stop only in thread 1"] \
+    "check pending breakpoint on foo"
diff --git a/gdb/testsuite/gdb.linespec/explicit.exp b/gdb/testsuite/gdb.linespec/explicit.exp
index b08d65953d2..7c8b2475881 100644
--- a/gdb/testsuite/gdb.linespec/explicit.exp
+++ b/gdb/testsuite/gdb.linespec/explicit.exp
@@ -574,7 +574,7 @@  namespace eval $testfile {
 	      allow-pending]} {
 	fail "set $tst"
     } else {
-	gdb_test "info break" ".*PENDING.*myfunction if foofoofoo == 1.*" $tst
+	gdb_test "info break" ".*PENDING.*myfunction\r\n\\s+stop only if foofoofoo == 1.*" $tst
     }
 
     gdb_exit
@@ -585,7 +585,7 @@  namespace eval $testfile {
 	      allow-pending]} {
 	fail "set $tst"
     } else {
-	gdb_test "info break" ".*PENDING.*myfunction if arg == 0" $tst
+	gdb_test "info break" ".*PENDING.*myfunction\r\n\\s+stop only if arg == 0" $tst
 
 	gdb_load [standard_output_file $exefile]
 	gdb_test "info break" \
diff --git a/gdb/testsuite/gdb.mi/mi-dprintf-pending.exp b/gdb/testsuite/gdb.mi/mi-dprintf-pending.exp
index 28f52938aeb..bb9987a5572 100644
--- a/gdb/testsuite/gdb.mi/mi-dprintf-pending.exp
+++ b/gdb/testsuite/gdb.mi/mi-dprintf-pending.exp
@@ -50,7 +50,8 @@  set bp_location1 [gdb_get_line_number "set breakpoint 1 here"]
 # Set pending dprintf via MI.
 set bp [mi_make_breakpoint_pending -number "1" -type "dprintf" \
 	    -disp "keep" -enabled "y" -pending "pendfunc1" \
-	    -original-location "pendfunc1"]
+	    -original-location "pendfunc1" \
+	    -script {\["printf \\\"hello\\\""\]}]
 mi_gdb_test "-dprintf-insert -f pendfunc1 \"hello\"" \
     ".*\\^done,$bp" "mi set dprintf"
 
diff --git a/gdb/testsuite/gdb.threads/del-pending-thread-bp-lib.c b/gdb/testsuite/gdb.threads/del-pending-thread-bp-lib.c
new file mode 100644
index 00000000000..15d1b9833dd
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/del-pending-thread-bp-lib.c
@@ -0,0 +1,22 @@ 
+/* Copyright 2023 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int global_var = 0;
+
+void
+foo (int arg)
+{
+  global_var = arg;
+}
diff --git a/gdb/testsuite/gdb.threads/del-pending-thread-bp.c b/gdb/testsuite/gdb.threads/del-pending-thread-bp.c
new file mode 100644
index 00000000000..938e05bc4d7
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/del-pending-thread-bp.c
@@ -0,0 +1,85 @@ 
+/* Copyright 2023 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <dlfcn.h>
+#include <pthread.h>
+#include <stdlib.h>
+
+pthread_barrier_t barrier;
+
+static void
+barrier_wait (pthread_barrier_t *b)
+{
+  int res = pthread_barrier_wait (b);
+  if (res != 0 && res != PTHREAD_BARRIER_SERIAL_THREAD)
+    abort ();
+}
+
+static void *
+thread_worker (void *arg)
+{
+  barrier_wait (&barrier);
+  return NULL;
+}
+
+void
+breakpt ()
+{
+  /* Nothing.  */
+}
+
+int
+main (void)
+{
+  void *handle;
+  void (*func)(int);
+  pthread_t thread;
+
+  if (pthread_barrier_init (&barrier, NULL, 2) != 0)
+    abort ();
+
+  if (pthread_create (&thread, NULL, thread_worker, NULL) != 0)
+    abort ();
+
+  breakpt ();
+
+  /* Allow the worker thread to complete.  */
+  barrier_wait (&barrier);
+
+  if (pthread_join (thread, NULL) != 0)
+    abort ();
+
+  breakpt ();
+
+  /* Now load the shared library.  */
+  handle = dlopen (SHLIB_NAME, RTLD_LAZY);
+  if (handle == NULL)
+    abort ();
+
+  /* Find the function symbol.  */
+  func = (void (*)(int)) dlsym (handle, "foo");
+
+  /* Call the library function.  */
+  func (1);
+
+  /* Unload the shared library.  */
+  if (dlclose (handle) != 0)
+    abort ();
+
+  breakpt ();
+
+  return 0;
+}
+
diff --git a/gdb/testsuite/gdb.threads/del-pending-thread-bp.exp b/gdb/testsuite/gdb.threads/del-pending-thread-bp.exp
new file mode 100644
index 00000000000..4ed05eaa42d
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/del-pending-thread-bp.exp
@@ -0,0 +1,108 @@ 
+# Copyright 2023 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This test checks that pending thread-specific breakpoints are
+# correctly deleted when the thread the breakpoint is for goes out of
+# scope.
+#
+# We also check that we can't create a pending thread-specific
+# breakpoint for a non-existent thread.
+
+require allow_shlib_tests
+
+standard_testfile
+
+set libname $testfile-lib
+set srcfile_lib $srcdir/$subdir/$libname.c
+set binfile_lib [standard_output_file $libname.so]
+
+if { [gdb_compile_shlib $srcfile_lib $binfile_lib {}] != "" } {
+    untested "failed to compile shared library 1"
+    return -1
+}
+
+set binfile_lib_target [gdb_download_shlib $binfile_lib]
+
+if { [prepare_for_testing "failed to prepare" $testfile $srcfile \
+	  [list debug \
+	       additional_flags=-DSHLIB_NAME=\"$binfile_lib_target\" \
+	       shlib_load pthreads]] } {
+    return -1
+}
+
+gdb_locate_shlib $binfile_lib
+
+if ![runto_main] {
+    return 0
+}
+
+# Run until we have two threads.
+gdb_breakpoint "breakpt"
+gdb_continue_to_breakpoint "first breakpt call"
+
+# Confirm that we have a thread '2'.
+gdb_test "info threads" "\r\n\\s+2\\s+\[^\r\n\]+"
+
+# Create a pending, thread-specific, breakpoint on 'foo'.
+gdb_breakpoint "foo thread 2" allow-pending
+set bpnum [get_integer_valueof "\$bpnum" "*INVALID*" \
+	       "get breakpoint number"]
+
+# Check we can't create a pending thread-specific breakpoint for a
+# non-existent thread.
+gdb_test "with breakpoint pending on -- break foo thread 99" \
+    "Unknown thread 99\\."
+
+# Continue to 'breakpt' again.  Don't use gdb_continue_to_breakpoint
+# as we are looking for the thread exited and breakpoint deleted
+# messages.
+set output [list "Continuing\\."]
+
+if {!([target_info exists gdb_protocol]
+      && ([target_info gdb_protocol] == "remote"
+	  || [target_info gdb_protocol] == "extended-remote"))} {
+    # Due to bug PR gdb/30129 we don't see the thread exited messages
+    # for remote targets.  When this bit of this test can be cleaned
+    # up.
+    lappend output "\\\[Thread \[^\r\n\]+ exited\\\]"
+}
+
+lappend output "Thread-specific breakpoint $bpnum deleted - thread 2 no longer in the thread list\\." \
+    "" \
+    "Thread 1 \[^\r\n\]+, breakpt \\(\\) at \[^\r\n\]+" \
+    "$decimal\\s+\[^\r\n\]+"
+
+gdb_test "continue" \
+    [multi_line {*}$output] \
+    "second breakpt call"
+
+# Confirm breakpoint has been deleted.
+gdb_test "info breakpoints $bpnum" \
+    "No breakpoint or watchpoint matching '$bpnum'\\."
+
+# Continue again.  This will pass through 'foo'.  We should not stop
+# in 'foo', the breakpoint has been deleted.  We should next stop in
+# breakpt again.
+gdb_test "continue" \
+    [multi_line \
+	 "Continuing\\." \
+	 "" \
+	 "Thread 1 \[^\r\n\]+ hit Breakpoint $decimal, breakpt \\(\\) at \[^\r\n\]+" \
+	 "$decimal\\s+\[^\r\n\]+"] \
+    "third breakpt call"
+gdb_test "bt 1" \
+    [multi_line \
+	 "#0\\s+breakpt \\(\\) at \[^\r\n\]+" \
+	 "\\(More stack frames follow\\.\\.\\.\\)"]