git.libre-soc.org Git - binutils-gdb.git/log

Add gdb.Frame.static_link method

This adds a new gdb.Frame.static_link method to the gdb Python layer.
This can be used to find the static link frame for a given frame.

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

Move follow_static_link to frame.c

This moves the follow_static_link function to frame.c and exports it
for use elsewhere. The API is changed slightly to make it more
generically useful.

Add block::function_block

This adds the method block::function_block, to easily access a block's
enclosing function block.

Add two convenience methods to block

This adds a couple of convenience methods, block::is_static_block and
block::is_global_block.

gdb/MAINTAINERS: add Guinevere Larsen as record-full maintainer

Change-Id: I67d8361560ce0fa553b2983184c9d18df8dbeb4a

gdb/MAINTAINERS: add Luis Machado as global maintainer

Change-Id: I211d64393f5c0da3c9ce1fcf5486504d34ed38f4

gdb/MAINTAINERS: add John Baldwin as global maintainer

Change-Id: Ic9164fd19c3da1381302a17176e8f0f814e9ac6c

gdb: normalize whitespaces in MAINTAINERS

Replace some spaces with tabs.

Change-Id: I89bbabd6610219649e7e99cd0dd7b0ed66d69b09

[gdb/tui] Factor out tui_noscroll_window et al

I noticed that tui_locator_window has an empty do_scroll_vertical and
do_scroll_horizontal, like tui_cmd_window, but unlike tui_cmd_window doesn't
have:
...
  bool can_scroll () const override
  {
    return false;
  }
...

I suspect that it probably doesn't matter, but regardless it's good to have
the same implementations of basic properties in all windows.

Ensure this by adding a class tui_noscroll_window, that has:
- an empty do_scroll_vertical and do_scroll_horizontal, and
- a can_scroll returning false
which both tui_locator_window and tui_cmd_window inherit.

Make all methods final to ensure no accidental overrides are left in the
inheriting classes.

Likewise add new classes representing basic window properties:
- tui_nofocus_window,
- tui_oneline_window,
- tui_nobox_window,
- tui_norefresh_window, and
- tui_always_visible_window.

The changes are only a refactoring, apart from adding the "final", which does
limit the range of behaviours for subclasses.

Tested on x86_64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

gdb: refactor make-target-delegates.py's ARGTYPES

Refactor the ARGTYPES regular expression in make-target-delegates.py
to eliminate '.*' for better control on what is matched. Also,
simplify the "E" match group, for which the optional SYMBOL becomes
redundant because that case can be matched by the "T" group.

After applying this patch, running './make-target-delegates.py' does not
change anything in 'target-delegates.c'.

Approved-By: Pedro Alves <pedro@palves.net>

gdb: regenerate target-delegates.c

I ran './make-target-delegates.py' and there is one minor difference,
where an older style declaration is converted to a newer
initialization style. Add this change.

Approved-By: Pedro Alves <pedro@palves.net>

[gdb/testsuite] Fix gdb.threads/stepi-over-clone.exp regexp

I ran into the following FAIL:
...
(gdb) PASS: gdb.threads/stepi-over-clone.exp: catch process syscalls
continue^M
Continuing.^M
^M
Catchpoint 2 (call to syscall clone), clone () at \
  ../sysdeps/unix/sysv/linux/x86_64/clone.S:78^M
warning: 78     ../sysdeps/unix/sysv/linux/x86_64/clone.S: \
  No such file or directory^M
(gdb) FAIL: gdb.threads/stepi-over-clone.exp: continue
...

All but one regexps in the .exp file use "clone\[23\]?" with "?" to
also accept "clone", except the failing case.  This commit fixes that
case to also use "?".

Furthermore, there are FAILs like this:
...
(gdb) PASS: gdb.threads/stepi-over-clone.exp: third_thread=false: \
   non-stop=on: displaced=off: i=0: continue
stepi^M
[New Thread 0x7ffff7ff8700 (LWP 15301)]^M
Hello from the first thread.^M
78      in ../sysdeps/unix/sysv/linux/x86_64/clone.S^M
(gdb) XXX: Consume the initial command
XXX: Consume new thread line
XXX: Consume first worker thread message
FAIL: gdb.threads/stepi-over-clone.exp: third_thread=false: non-stop=on: \
  displaced=off: i=0: stepi
...
because this output is expected instead:
...
Hello from the first thread.^M
0x00000000004212cd in clone3 ()^M
...

The root cause for the difference is the presence of .debug_line info for
clone.

Fix this by updating the relevant regexps.

Tested on x86_64-linux, specifically:
- openSUSE Leap 15.4 (where the FAILs where observed), and
- openSUSE Tumbleweed (where the FAILs where not observed).

Co-Authored-By: Pedro Alves <pedro@palves.net>
Approved-By: Pedro Alves <pedro@palves.net>
Change-Id: I74ca9e7d4cfe6af294fd50e8c509fcbad289b78c

gdb: implement missing debug handler hook for Python

This commit builds on the previous commit, and implements the
extension_language_ops::handle_missing_debuginfo function for Python.
This hook will give user supplied Python code a chance to help find
missing debug information.

The implementation of the new hook is pretty minimal within GDB's C++
code; most of the work is out-sourced to a Python implementation which
is modelled heavily on how GDB's Python frame unwinders are
implemented.

The following new commands are added as commands implemented in
Python, this is similar to how the Python unwinder commands are
implemented:

  info missing-debug-handlers
  enable missing-debug-handler LOCUS HANDLER
  disable missing-debug-handler LOCUS HANDLER

To make use of this extension hook a user will create missing debug
information handler objects, and registers these handlers with GDB.
When GDB encounters an objfile that is missing debug information, each
handler is called in turn until one is able to help.  Here is a
minimal handler that does nothing useful:

  import gdb
  import gdb.missing_debug

  class MyFirstHandler(gdb.missing_debug.MissingDebugHandler):
      def __init__(self):
          super().__init__("my_first_handler")

      def __call__(self, objfile):
          # This handler does nothing useful.
          return None

  gdb.missing_debug.register_handler(None, MyFirstHandler())

Returning None from the __call__ method tells GDB that this handler
was unable to find the missing debug information, and GDB should ask
any other registered handlers.

By extending the __call__ method it is possible for the Python
extension to locate the debug information for objfile and return a
value that tells GDB how to use the information that has been located.

Possible return values from a handler:

  - None: This means the handler couldn't help.  GDB will call other
          registered handlers to see if they can help instead.

  - False: The handler has done all it can, but the debug information
           for the objfile still couldn't be found.  GDB will not call
   any other handlers, and will continue without the debug
   information for objfile.

  - True: The handler has installed the debug information into a
          location where GDB would normally expect to find it.  GDB
  should look again for the debug information.

  - A string: The handler can return a filename, which is the file
              containing the missing debug information.  GDB will load
      this file.

When a handler returns True, GDB will look again for the debug
information, but only using the standard built-in build-id and
.gnu_debuglink based lookup strategies.  It is not possible for an
extension to trigger another debuginfod lookup; the assumption is that
the debuginfod server is remote, and out of the control of extensions
running within GDB.

Handlers can be registered globally, or per program space.  GDB checks
the handlers for the current program space first, and then all of the
global handles.  The first handler that returns a value that is not
None, has "handled" the objfile, at which point GDB continues.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>

gdb: add an extension language hook for missing debug info

This commit adds a new extension_language_ops hook which allows an
extension to handle the case where GDB can't find a separate debug
information file for a particular objfile.

This commit doesn't actually implement the hook for any of GDB's
extension languages, the next commit will do that.  This commit just
adds support for the hook to extension-priv.h and extension.[ch], and
then reworks symfile-debug.c to call the hook.

Right now the hook will always return its default value, which means
GDB should do nothing different.  As such, there should be no user
visible changes after this commit.

I'll give a brief description of what the hook does here so that we
can understand the changes in symfile-debug.c.  The next commit adds a
Python implementation for this new hook, and gives a fuller
description of the new functionality.

Currently, when looking for separate debug information GDB tries three
things, in this order:

  1. Use the build-id to find the required debug information,

  2. Check for .gnu_debuglink section and use that to look up the
  required debug information,

  3. Check with debuginfod to see if it can supply the required
  information.

The new extension_language_ops::handle_missing_debuginfo hook is
called if all three steps fail to find any debug information.  The
hook has three possible return values:

  a. Nothing, no debug information is found, GDB continues without the
  debug information for this objfile.  This matches the current
  behaviour of GDB, and is the default if nothing is implementing this
  new hook,

  b. Install debug information into a location that step #1 or #2
  above would normally check, and then request that GDB repeats steps
  #1 and #2 in the hope that GDB will now find the debug information.
  If the debug information is still not found then GDB carries on
  without the debug information.  If the debug information is found
  the GDB loads it and carries on,

  c. Return a filename for a file containing the required debug
  information.  GDB loads the contents of this file and carries on.

The changes in this commit mostly involve placing the core of
objfile::find_and_add_separate_symbol_file into a loop which allows
for steps #1 and #2 to be repeated.

We take care to ensure that debuginfod is only queried once, the first
time through.  The assumption is that no extension is going to be able
to control the replies from debuginfod, so there's no point making a
second request -- and as these requests go over the network, they
could potentially be slow.

The warnings that find_and_add_separate_symbol_file collects are
displayed only once assuming that no debug information is found.  If
debug information is found, even after the extension has operated,
then the warnings are not shown; remember, these are warnings from GDB
about failure to find any suitable debug information, so it makes
sense to hide these if debug information is found.

Approved-By: Tom Tromey <tom@tromey.com>

gdb: refactor objfile::find_and_add_separate_symbol_file

This is purely a refactoring commit.

This commit splits objfile::find_and_add_separate_symbol_file into
some separate helper functions. My hope is that the steps for looking
up separate debug information are now clearer.

In a later commit I'm going to extend
objfile::find_and_add_separate_symbol_file, with some additional
logic, so starting with a simpler function will make the following
changes easier.

When reading objfile::find_and_add_separate_symbol_file after this
commit, you might be tempted to think that removing the `has_dwarf`
local variable would be a good additional cleanup. After the next
commit though it makes more sense to retain this local, so I've left
this in place for now.

There should be no user visible changes after this commit.

Approved-By: Tom Tromey <tom@tromey.com>

gdb: merge debug symbol file lookup code from coffread & elfread paths

This commit merges the code that looks for and loads the separate
debug symbol files from coffread.c and elfread.c.  The factored out
code is moved into a new objfile::find_and_add_separate_symbol_file()
method.

For the elfread.c path there should be no user visible changes after
this commit.

For the coffread.c path GDB will now attempt to perform a debuginfod
lookup for the missing debug information, assuming that GDB can find a
build-id in the COFF file.

I don't know if COFF files can include a build-id, but I the existing
coffread.c code already includes a call to
find_separate_debug_file_by_build-id, so I know that it is at least OK
for GDB to ask a COFF file for a build-id.  If the COFF file doesn't
include a build-id then the debuginfod lookup code will not trigger
and the new code is harmless.

If the COFF file does include a build-id, then we're going to end up
asking debuginfod for the debug file.  As build-ids should be unique,
this should be harmless, even if debuginfod doesn't contain any
suitable debug data, it just costs us one debuginfod lookup, so I'm
not too worried about this for now.

As with the previous commit, I've done some minimal testing using the
mingw toolchain on a Linux machine, GDB seems to still access the
split debug information just fine.

Approved-By: Tom Tromey <tom@tromey.com>

gdb/coffread: bring separate debug file logic into line with elfread.c

In this commit:

  commit 8a92335bfca80cc9b4cd217505ea0dcbfdefbf07
  Date:   Fri Feb 1 19:39:04 2013 +0000

the logic for when we try to load a separate debug file in elfread.c
was extended.  The new code checks that the objfile doesn't already
have a separate debug objfile linked to it, and that the objfile isn't
itself a separate debug objfile for some other objfile.

The coffread code wasn't extended at the same time.

I don't know if it's possible for the coffread code to get into the
same state where these checks are needed, but I don't see why having
these checks would be a problem.  In a later commit I plan to merge
this part of the elfread and coffread code, so bringing these two
pieces of code into line first makes that job easier.

I've tested this with a simple test binary compiled with the mingw
toolchain on a Linux host.  After compiling the binary and splitting
out the debug info GDB still finds and loads the separate debug info.

Approved-By: Tom Tromey <tom@tromey.com>

Fix another linker command line option that was not being recognised in its long form.

PR 28910
* lexsup.c (ld_options): Ensure that the --mri-script option is correctly recognised.

Improve objdump's handling of compressed sections.

  PR 31062
  * objdump.c (decompressed_dumps): New local variable. (usage): Mention the -z/--decompress option. (long_options): Add --decompress. (dump_section_header): Add "COMPRESSED" to the Flags field of any compressed section. (dump_section): Warn users when dumping a compressed section. (display_any_bfd): Decompress the section if decompressed_dumps is true. (main): Handle the -z/--decompress option.
  * NEWS: Mention the new feature.
  * doc/binutils.texi: Document the new feature.
  * testsuite/binutils-all/objdump.s: Update expected output.
  * testsuite/binutils-all/objdump.exp: Add test of -Z -s.
  * testsuite/binutils-all/objdump.Zs: New file.
  * readelf.c (maybe_expand_or_relocate_section): New function. Contains common code found in dump functions.  Adds a note message if a compressed section is not being decompressed. (dump_section_as_strings): Use new function. (dump_section_as_bytes): Likewise.

Automatic date update in version.in

[gdb/tui] Don't include border_width in left_margin

Currently left_margin does not match its documentation:
...
  /* Return the size of the left margin space, this is the space used to
     display things like breakpoint markers.  */
  int left_margin () const
  { return box_width () + TUI_EXECINFO_SIZE + extra_margin (); }
...

It is stated that the left margin is reserved to display things, but
the box_width is not used for that.

Fix this by dropping box_width () from the left_margin calculation.

Tested on x86_64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

[gdb/tui] Add tui_win_info::{box_width,box_size}

In tui_source_window::set_contents we have:
...
  /* Take hilite (window border) into account, when
     calculating the number of lines.  */
  int nlines = height - 2;
...

The '2' represents the total size of the window border (or box, in can_box
terms), in this case one line at the top and one line at the bottom.

Likewise, '1' is used to represent the width of the window border.

Introduce new functions:
- tui_win_info::box_width () and
- tui_win_info::box_size ()
that can be used instead instead of these hardcoded constants.

Implement these such that they return 0 when can_box () == false.

Tested patch completeness by making all windows unboxed:
...
@@ -85,7 +85,7 @@ struct tui_win_info
   /* Return true if this window can be boxed.  */
   virtual bool can_box () const
   {
-    return true;
+    return false;
   }

   int box_width () const
...
and test-driving TUI.

This required eliminating an assert in
tui_source_window_base::show_source_content, I've included that part as well.

Tested on x86_64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

[gdb/tui] Refactor prefresh call in tui_source_window_base::refresh_window

Currently the call to prefresh in tui_source_window_base::refresh_window looks
like:
...
  prefresh (m_pad.get (), 0, pad_x, y + 1, x + left_margin,
    y + m_content.size (), x + left_margin + view_width - 1);
...

This is hard to parse.  It's not obvious what the arguments mean, and there's
repetition in the argument calculation.

Fix this by rewriting the call as follows:
- use sminrow, smincol, smaxrow and smaxcol variables for the last
  4 arguments, and
- calculate the smaxrow and smaxcol variables based on the sminrow and
  smincol variables.

Tested on x86_64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

Fix the gdb.ada/inline-section-gc.exp test

The original intention of the test appears to be checking to make sure
setting a breakpoint in an inlined function didn't set multiple
breakpoints where one of them was at address 0.

The gdb.ada/inline-section-gc.exp test may pass or fail depending on the
version of gnat.  Per the discussion on IRC, the ada inlining appears to
have some target dependencies.  In this test there are two functions,
callee and caller. Function calee is inlined into caller.  The test sets
a breakpoint in function callee.  The reported location where the
breakpoint is set may be at the requested location in callee or the
location in caller after callee has been inlined.  The test needs to
accept either location as correct provided the breakpoint address is not
zero.

This patch checks to see if the reported breakpoint is in function callee
or function caller and fails if the breakpoint address is 0x0.  The line
number where the breakpoint is set will match the requested line if the
breakpoint location is reported is callee.adb.  If the breakpoint is
reported in caller.adb, the line number in caller is the breakpoint
location in callee where it is inlined into caller.

This patch fixes the single regression failure for the test on PowerPC.
It does not introduce any failures on X86-64.

GNU-ld: ARM: Issues when trying to set target output architecture

PR 28910
* lexsup.c (ld_options): Ensure that the --format option is correctly recognised.

Regenerate gas/config.in and ld/configure

commit d173146d9 "MIPS: Change all E_MIPS_* to EF_MIPS_*"
changed gas/config.in to rename USE_E_MIPS_ABI_O32 to USE_EF_MIPS_ABI_O32
this new name sorts differently when regenerating gas/config.in

commit e922d1eaa "Add ability to change linker warning messages into
errors when reporting executable stacks and/or executable segments."
Introduced two new help strings for --enable-error-execstack and
--enable-error-rwx-segments in configure.ac which weren't included
in ld/configure when regenerated.

* gas/config.in: Regenerate.
* ld/configure: Likewise.

Add documentation for the MIPS assembler's -march=from-abi command line option

MIPS: Fix binutils-all tests for r6 triples

Fix redundant space typo in linker documentation.

Cancel execution command on thread exit, when stepping, nexting, etc.

If your target has no support for TARGET_WAITKIND_NO_RESUMED events
(and no way to support them, such as the yet-unsubmitted AMDGPU
target), and you step over thread exit with scheduler-locking on, this
is what you get:

(gdb) n
[Thread ... exited]
*hang*

Getting back the prompt by typing Ctrl-C may not even work, since no
inferior thread is running to receive the SIGINT.  Even if it works,
it seems unnecessarily harsh.  If you started an execution command for
which there's a clear thread of interest (step, next, until, etc.),
and that thread disappears, then I think it's more user friendly if
GDB just detects the situation and aborts the command, giving back the
prompt.

That is what this commit implements.  It does this by explicitly
requesting the target to report thread exit events whenever the main
resumed thread has a thread_fsm.  Note that unlike stepping over a
breakpoint, we don't need to enable clone events in this case.

With this patch, we get:

(gdb) n
[Thread 0x7ffff7d89700 (LWP 3961883) exited]
Command aborted, thread exited.
(gdb)

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I901ab64c91d10830590b2dac217b5264635a2b95

Document remote clone events, and QThreadOptions packet

This commit documents in both manual and NEWS:

- the new remote clone event stop reply,
- the new QThreadOptions packet and its current defined options,
- the associated "set/show remote thread-events-packet" command,
- and the associated QThreadOptions qSupported feature.

Approved-By: Eli Zaretskii <eliz@gnu.org>
Change-Id: Ic1c8de1fefba95729bbd242969284265de42427e

Testcases for stepping over thread exit syscall (PR gdb/27338)

Add new gdb.threads/step-over-thread-exit.exp and
gdb.threads/step-over-thread-exit-while-stop-all-threads.exp
testcases, exercising stepping over thread exit syscall. These make
use of lib/my-syscalls.S to define the exit syscall.

Co-authored-by: Pedro Alves <pedro@palves.net>
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338
Change-Id: Ie8b2c5747db99b7023463a897a8390d9e814a9c9

gdb/testsuite/lib/my-syscalls.S: Refactor new SYSCALL macro

Refactor the syscall assembly code in gdb/testsuite/lib/my-syscalls.S
behind a SYSCALL macro so that it's easy to add new syscalls without
duplicating code.

Note that the way the macro is implemented, it only works correctly
for syscalls with up to 3 arguments, and, if the syscall doesn't
return (the macro doesn't bother to save/restore callee-saved
registers).

The following patch will want to use the macro to define a wrapper for
the "exit" syscall, so the limitations continue to be sufficient.

Change-Id: I8acf1463b11a084d6b4579aaffb49b5d0dea3bba
Reviewed-By: Andrew Burgess <aburgess@redhat.com>

Report thread exit event for leader if reporting thread exit events

If GDB sets the GDB_THREAD_OPTION_EXIT option on a thread, then if the
thread disappears from the thread list, GDB expects to shortly see a
thread exit event for it.  See e.g., here, in
remote_target::update_thread_list():

    /* Do not remove the thread if we've requested to be
       notified of its exit.  For example, the thread may be
       displaced stepping, infrun will need to handle the
       exit event, and displaced stepping info is recorded
       in the thread object.  If we deleted the thread now,
       we'd lose that info.  */
    if ((tp->thread_options () & GDB_THREAD_OPTION_EXIT) != 0)
      continue;

There's one scenario that is deleting a thread from the
remote/gdbserver thread list without ever reporting a corresponding
thread exit event though -- check_zombie_leaders.  This can lead to
GDB getting confused.  For example, with a following patch that
enables GDB_THREAD_OPTION_EXIT whenever schedlock is enabled, we'd see
this regression:

$ make check RUNTESTFLAGS="--target_board=native-extended-gdbserver" TESTS="gdb.threads/no-unwaited-for-left.exp"
...
Running src/gdb/testsuite/gdb.threads/no-unwaited-for-left.exp ...
FAIL: gdb.threads/no-unwaited-for-left.exp: continue stops when the main thread exits (timeout)
... some more cascading FAILs ...

gdb.log shows:

(gdb) continue
Continuing.
FAIL: gdb.threads/no-unwaited-for-left.exp: continue stops when the main thread exits (timeout)

A passing run would have resulted in:

(gdb) continue
Continuing.
No unwaited-for children left.
(gdb) PASS: gdb.threads/no-unwaited-for-left.exp: continue stops when the main thread exits

note how the leader thread is not listed in the remote-reported XML
thread list below:

(gdb) set debug remote 1
(gdb) set debug infrun 1
(gdb) info threads
   Id   Target Id                                Frame
* 1    Thread 1163850.1163850 "no-unwaited-for" main () at /home/pedro/rocm/gdb/build/gdb/testsuite/../../../src/gdb/testsuite/gdb.threads/no-unwaited-for-left.c:65
   3    Thread 1163850.1164130 "no-unwaited-for" [remote] Sending packet: $Hgp11c24a.11c362#39
(gdb) c
Continuing.
[infrun] clear_proceed_status_thread: 1163850.1163850.0
...
     [infrun] resume_1: step=1, signal=GDB_SIGNAL_0, trap_expected=1, current thread [1163850.1163850.0] at 0x55555555534f
     [remote] Sending packet: $QPassSignals:#f3
     [remote] Packet received: OK
     [remote] Sending packet: $QThreadOptions;3:p11c24a.11c24a#f3
     [remote] Packet received: OK
...
     [infrun] target_set_thread_options: [options for Thread 1163850.1163850 are now 0x3]
...
   [infrun] do_target_resume: resume_ptid=1163850.1163850.0, step=0, sig=GDB_SIGNAL_0
   [remote] Sending packet: $vCont;c:p11c24a.11c24a#98
   [infrun] prepare_to_wait: prepare_to_wait
   [infrun] reset: reason=handling event
   [infrun] maybe_set_commit_resumed_all_targets: enabling commit-resumed for target extended-remote
   [infrun] maybe_call_commit_resumed_all_targets: calling commit_resumed for target extended-remote
[infrun] fetch_inferior_event: exit
[infrun] fetch_inferior_event: enter
   [infrun] scoped_disable_commit_resumed: reason=handling event
   [infrun] random_pending_event_thread: None found.
   [remote] wait: enter
     [remote] Packet received: N
   [remote] wait: exit
   [infrun] print_target_wait_results: target_wait (-1.0.0 [process -1], status) =
   [infrun] print_target_wait_results:   -1.0.0 [process -1],
   [infrun] print_target_wait_results:   status->kind = NO_RESUMED
   [infrun] handle_inferior_event: status->kind = NO_RESUMED
   [remote] Sending packet: $Hgp0.0#ad
   [remote] Packet received: OK
   [remote] Sending packet: $qXfer:threads:read::0,1000#92
   [remote] Packet received: l<threads>\n<thread id="p11c24a.11c362" core="0" name="no-unwaited-for" handle="0097d8f7ff7f0000"/>\n</threads>\n
   [infrun] handle_no_resumed: TARGET_WAITKIND_NO_RESUMED (ignoring: found resumed)
...

... however, infrun decided there was a resumed thread still, so
ignored the TARGET_WAITKIND_NO_RESUMED event.  Debugging GDB, we see
that the "found resumed" thread that GDB finds, is the leader thread.
Even though that thread is not on the remote-reported thread list, it
is still on the GDB thread list, due to the special case in remote.c
mentioned above.

This commit addresses the issue by fixing GDBserver to report a thread
exit event for the zombie leader too, i.e., making GDBserver respect
the "if thread has GDB_THREAD_OPTION_EXIT set, report a thread exit"
invariant.  To do that, it takes a bit more code than one would
imagine off hand, due to the fact that we currently always report LWP
exit pending events as TARGET_WAITKIND_EXITED, and then decide whether
to convert it to TARGET_WAITKIND_THREAD_EXITED just before reporting
the event to GDBserver core.  For the zombie leader scenario
described, we need to record early on that we want to report a
THREAD_EXITED event, and then make sure that decision isn't lost along
the way to reporting the event to GDBserver core.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I1e68fccdbc9534434dee07163d3fd19744c8403b

Don't resume new threads if scheduler-locking is in effect

If scheduler-locking is in effect, e.g., with "set scheduler-locking
on", and you step over a function that spawns a new thread, the new
thread is allowed to run free, at least until some event is hit, at
which point, whether the new thread is re-resumed depends on a number
of seemingly random factors. E.g., if the target is all-stop, and the
parent thread hits a breakpoint, and GDB decides the breakpoint isn't
interesting to report to the user, then the parent thread is resumed,
but the new thread is left stopped.

I think that letting the new threads run with scheduler-locking
enabled is a defect. This commit fixes that, making use of the new
clone events on Linux, and of target_thread_events() on targets where
new threads have no connection to the thread that spawned them.

Testcase and documentation changes included.

Approved-By: Eli Zaretskii <eliz@gnu.org>
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Ie12140138b37534b7fc1d904da34f0f174aa11ce

gdbserver: Queue no-resumed event after thread exit

Normally, if the last resumed thread on the target exits, the server
sends a no-resumed event to GDB.  If however, GDB enables the
GDB_THREAD_OPTION_EXIT option on a thread, and, that thread exits, the
server sends a thread exit event for that thread instead.

In all-stop RSP mode, since events can only be forwarded to GDB one at
a time, and the whole target stops whenever an event is reported, GDB
resumes the target again after getting a THREAD_EXITED event, and then
the server finally reports back a no-resumed event if/when
appropriate.

For non-stop RSP though, events are asynchronous, and if the server
sends a thread-exit event for the last resumed thread, the no-resumed
event is never sent.  This patch makes sure that in non-stop mode, the
server queues a no-resumed event after the thread-exit event if it was
the last resumed thread that exited.

Without this, we'd see failures in step-over-thread-exit testcases
added later in the series, like so:

   continue
   Continuing.
- No unwaited-for children left.
- (gdb) PASS: gdb.threads/step-over-thread-exit.exp: displaced-stepping=off: non-stop=on: target-non-stop=on: schedlock=off: ns_stop_all=1: continue stops when thread exits
+ FAIL: gdb.threads/step-over-thread-exit.exp: displaced-stepping=off: non-stop=on: target-non-stop=on: schedlock=off: ns_stop_all=1: continue stops when thread exits (timeout)

(and other similar ones)

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I927d78b30f88236dbd5634b051a716f72420e7c7

stop_all_threads: (re-)enable async before waiting for stops

Running the
gdb.threads/step-over-thread-exit-while-stop-all-threads.exp testcase
added later in the series against gdbserver, after the
TARGET_WAITKIND_NO_RESUMED fix from the following patch, would run
into an infinite loop in stop_all_threads, leading to a timeout:

  FAIL: gdb.threads/step-over-thread-exit-while-stop-all-threads.exp: displaced-stepping=off: target-non-stop=on: iter 0: continue (timeout)

The is really a latent bug, and it is about the fact that
stop_all_threads stops listening to events from a target as soon as it
sees a TARGET_WAITKIND_NO_RESUMED, ignoring that
TARGET_WAITKIND_NO_RESUMED may be delayed.  handle_no_resumed knows
how to handle delayed no-resumed events, but stop_all_threads was
never taught to.

In more detail, here's what happens with that testcase:

#1 - Multiple threads report breakpoint hits to gdb.

#2 - gdb picks one events, and it's for thread 1.  All other stops are
     left pending.  thread 1 needs to move past a breakpoint, so gdb
     stops all threads to start an inline step over for thread 1.
     While stopping threads, some of the threads that were still
     running report events that are also left pending.

#2 - gdb steps thread 1

#3 - Thread 1 exits while stepping (it steps over an exit syscall),
     gdbserver reports thread exit for thread 1

#4 - Thread 1 was the last resumed thread, so gdbserver also reports
     no-resumed:

    [remote]   Notification received: Stop:w0;p3445d0.3445d3
    [remote] Sending packet: $vStopped#55
    [remote] Packet received: N
    [remote] Sending packet: $vStopped#55
    [remote] Packet received: OK

#5 - gdb processes the thread exit for thread 1, finishes the step
     over and restarts threads.

#6 - gdb picks the next event to process out of one of the resumed
     threads with pending events:

    [infrun] random_resumed_with_pending_wait_status: Found 32 events, selecting #11

#7 - This is again a breakpoint hit and the breakpoint needs to be
     stepped over too, so gdb starts a step-over dance again.

#8 - We reach stop_all_threads, which finds that some threads need to
     be stopped.

#9 - wait_one finally consumes the no-resumed event queue by #4.
     Seeing this, wait_one disable target async, to stop listening for
     events out of the remote target.

#10 - We still haven't seen all the stops expected, so
      stop_all_threads tries another iteration.

#11 - Because the remote target is no longer async, and there are no
      other targets, wait_one return no-resumed immediately without
      polling the remote target.

#12 - We still haven't seen all the stops expected, so
      stop_all_threads tries another iteration.  goto #11, looping
      forever.

Fix this by explicitly enabling/re-enabling target async on targets
that can async, before waiting for stops.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Ie3ffb0df89635585a6631aa842689cecc989e33f

gdb: clear step over information on thread exit (PR gdb/27338)

GDB doesn't handle correctly the case where a thread steps over a
breakpoint (using either in-line or displaced stepping), and the
executed instruction causes the thread to exit.

Using the test program included later in the series, this is what it
looks like with displaced-stepping, on x86-64 Linux, where we have two
displaced-step buffers:

  $ ./gdb -q -nx --data-directory=data-directory build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit -ex "b my_exit_syscall" -ex r
  Reading symbols from build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit...
  Breakpoint 1 at 0x123c: file src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S, line 68.
  Starting program: build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/usr/lib/../lib/libthread_db.so.1".
  [New Thread 0x7ffff7c5f640 (LWP 2915510)]
  [Switching to Thread 0x7ffff7c5f640 (LWP 2915510)]

  Thread 2 "step-over-threa" hit Breakpoint 1, my_exit_syscall () at src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S:68
  68              syscall
  (gdb) c
  Continuing.
  [New Thread 0x7ffff7c5f640 (LWP 2915524)]
  [Thread 0x7ffff7c5f640 (LWP 2915510) exited]
  [Switching to Thread 0x7ffff7c5f640 (LWP 2915524)]

  Thread 3 "step-over-threa" hit Breakpoint 1, my_exit_syscall () at src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S:68
  68              syscall
  (gdb) c
  Continuing.
  [New Thread 0x7ffff7c5f640 (LWP 2915616)]
  [Thread 0x7ffff7c5f640 (LWP 2915524) exited]
  [Switching to Thread 0x7ffff7c5f640 (LWP 2915616)]

  Thread 4 "step-over-threa" hit Breakpoint 1, my_exit_syscall () at src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S:68
  68              syscall
  (gdb) c
  Continuing.
  ... hangs ...

The first two times we do "continue", we displaced-step the syscall
instruction that causes the thread to exit.  When the thread exits,
the main thread, waiting on pthread_join, is unblocked.  It spawns a
new thread, which hits the breakpoint on the syscall again.  However,
infrun was never notified that the displaced-stepping threads are done
using the displaced-step buffer, so now both buffers are marked as
used.  So when we do the third continue, there are no buffers
available to displaced-step the syscall, so the thread waits forever
for its turn.

When trying the same but with in-line step over (displaced-stepping
disabled):

  $ ./gdb -q -nx --data-directory=data-directory \
  build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit \
    -ex "b my_exit_syscall" -ex "set displaced-stepping off" -ex r
  Reading symbols from build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit...
  Breakpoint 1 at 0x123c: file src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S, line 68.
  Starting program: build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/usr/lib/../lib/libthread_db.so.1".
  [New Thread 0x7ffff7c5f640 (LWP 2928290)]
  [Switching to Thread 0x7ffff7c5f640 (LWP 2928290)]

  Thread 2 "step-over-threa" hit Breakpoint 1, my_exit_syscall () at src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S:68
  68              syscall
  (gdb) c
  Continuing.
  [Thread 0x7ffff7c5f640 (LWP 2928290) exited]
  No unwaited-for children left.
  (gdb) i th
    Id   Target Id                                             Frame
    1    Thread 0x7ffff7c60740 (LWP 2928285) "step-over-threa" 0x00007ffff7f7c9b7 in __pthread_clockjoin_ex () from /usr/lib/libpthread.so.0

  The current thread <Thread ID 2> has terminated.  See `help thread'.
  (gdb) thread 1
  [Switching to thread 1 (Thread 0x7ffff7c60740 (LWP 2928285))]
  #0  0x00007ffff7f7c9b7 in __pthread_clockjoin_ex () from /usr/lib/libpthread.so.0
  (gdb) c
  Continuing.
  ^C^C
  ... hangs ...

The "continue" causes an in-line step to occur, meaning the main
thread is stopped while we step the syscall.  The stepped thread exits
when executing the syscall, the linux-nat target notices there are no
more resumed threads to be waited for, so returns
TARGET_WAITKIND_NO_RESUMED, which causes the prompt to return.  But
infrun never clears the in-line step over info.  So if we try
continuing the main thread, GDB doesn't resume it, because it thinks
there's an in-line step in progress that we need to wait for to
finish, and we are stuck there.

To fix this, infrun needs to be informed when a thread doing a
displaced or in-line step over exits.  We can do that with the new
target_set_thread_options mechanism which is optimal for only enabling
exit events of the thread that needs it; or, if that is not supported,
by using target_thread_events, which enables thread exit events for
all threads.  This is done by this commit.

This patch then modifies handle_inferior_event in infrun.c to clean up
any step-over the exiting thread might have been doing at the time of
the exit.  The cases to consider are:

- the exiting thread was doing an in-line step-over with an all-stop
   target
- the exiting thread was doing an in-line step-over with a non-stop
   target
- the exiting thread was doing a displaced step-over with a non-stop
   target

The displaced-stepping buffer implementation in displaced-stepping.c
is modified to account for the fact that it's possible that we
"finish" a displaced step after a thread exit event.  The buffer that
the exiting thread was using is marked as available again and the
original instructions under the scratch pad are restored.  However, it
skips applying the fixup, which wouldn't make sense since the thread
does not exist anymore.

Another case that needs handling is if a displaced-stepping thread
exits, and the event is reported while we are in stop_all_threads.  We
should call displaced_step_finish in the handle_one function, in that
case.  It was already called in other code paths, just not the "thread
exited" path.

This commit doesn't make infrun ask the target to report the
TARGET_WAITKIND_THREAD_EXITED events yet, that'll be done later in the
series.

Note that "stop_print_frame = false;" line is moved to normal_stop,
because TARGET_WAITKIND_THREAD_EXITED can also end up with the event
transmorphed into TARGET_WAITKIND_NO_RESUMED.  Moving it to
normal_stop keeps it centralized.

Co-authored-by: Simon Marchi <simon.marchi@efficios.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I745c6955d7ef90beb83bcf0ff1d1ac8b9b6285a5

Implement GDB_THREAD_OPTION_EXIT support for native Linux

This implements support for the new GDB_THREAD_OPTION_EXIT thread
option for native Linux.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Ia69fc0b9b96f9af7de7cefc1ddb1fba9bbb0bb90
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338

Implement GDB_THREAD_OPTION_EXIT support for Linux GDBserver

This implements support for the new GDB_THREAD_OPTION_EXIT thread
option for Linux GDBserver.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I96b719fdf7fee94709e98bb3a90751d8134f3a38
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338

Introduce GDB_THREAD_OPTION_EXIT thread option, fix step-over-thread-exit

When stepping over a breakpoint with displaced stepping, GDB needs to
be informed if the stepped thread exits, otherwise the displaced
stepping buffer that was allocated to that thread leaks, and this can
result in deadlock, with other threads waiting for their turn to
displaced step, but their turn never comes.

Similarly, when stepping over a breakpoint in line, GDB also needs to
be informed if the stepped thread exits, so that is can clear the step
over state and re-resume threads.

This commit makes it possible for GDB to ask the target to report
thread exit events for a given thread, using the new "thread options"
mechanism introduced by a previous patch.

This only adds the core bits. Following patches in the series will
teach the Linux backends (native & gdbserver) to handle the
GDB_THREAD_OPTION_EXIT option, and then a later patch will make use of
these thread exit events to clean up displaced stepping and inline
stepping state properly.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I96b719fdf7fee94709e98bb3a90751d8134f3a38
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338

Move deleting thread on TARGET_WAITKIND_THREAD_EXITED to core

Currently, infrun assumes that when TARGET_WAITKIND_THREAD_EXITED is
reported, the corresponding GDB thread has already been removed from
the GDB thread list.

Later in the series, that will no longer work, as infrun will need to
refer to the thread's thread_info when it processes
TARGET_WAITKIND_THREAD_EXITED.

As preparation, this patch makes deleting the GDB thread
responsibility of infrun, instead of the target.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I013d87f61ffc9aaca49f0d6ce2a43e3ea69274de

gdbserver/linux-low.cc: Ignore event_ptid if TARGET_WAITKIND_IGNORE

gdbserver's linux_process_target::wait loops if:

- called in sync mode, and,
- wait_1 returns TARGET_WAITKIND_IGNORE, _and_,
- wait_1 also returns null_ptid.

The null_ptid check fails however when this path is taken:

   ptid_t
   linux_process_target::filter_exit_event (lwp_info *event_child,
    target_waitstatus *ourstatus)
   {
   ...
     if (!is_leader (thread))
       {
if (report_exit_events_for (thread))
   ourstatus->set_thread_exited (0);
else
   ourstatus->set_ignore ();            <<<<<<<

delete_lwp (event_child);
       }
     return ptid;
   }

This makes linux_process_target::wait return TARGET_WAITKIND_IGNORE in
sync mode, which is unexpected by the core and fails an assertion.

This commit fixes it by just making linux_process_target::wait loop if
it got a TARGET_WAITKIND_IGNORE, irrespective of event_ptid.

Change-Id: I39776908a6c75cbd68aa04139ffcf7be334868cf

all-stop/synchronous RSP support thread-exit events

Currently, GDB does not understand the THREAD_EXITED stop reply in
remote all-stop mode. There's no good reason for this, it just
happened that THREAD_EXITED was only ever reported in non-stop mode so
far. This patch teaches GDB to parse that event in all-stop RSP too.
There is no need to add a qSupported feature for this, because the
server won't send a THREAD_EXITED event unless GDB explicitly asks for
it, with QThreadEvents, or with the GDB_THREAD_OPTION_EXIT
QThreadOptions option added in the next patch.

Change-Id: Ide5d12391adf432779fe4c79526801c4a5630966

Remove gdb/19675 kfails (displaced stepping + clone)

Now that gdb/19675 is fixed for both native and gdbserver GNU/Linux,
remove the gdb/19675 kfails.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I95c1c38ca370100675d303cd3c8995860bef465d

gdbserver: Hide and don't detach pending clone children

This commit extends the logic added by these two commits from a while
ago:

#1  7b961964f866  (gdbserver: hide fork child threads from GDB),
#2  df5ad102009c  (gdb, gdbserver: detach fork child when detaching from fork parent)

... to handle thread clone events, which are very similar to (v)fork
events.

For #1, we want to hide clone children as well, so just update the
comments.

For #2, unlike (v)fork children, pending clone children aren't full
processes, they're just threads, so don't detach them in
handle_detach.  linux-low.cc will take care of detaching them along
with all other threads of the process, there's nothing special that
needs to be done.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I7f5901d07efda576a2522d03e183994e071b8ffc

Thread options & clone events (Linux GDBserver)

This patch teaches the Linux GDBserver backend to report clone events
to GDB, when GDB has requested them with the GDB_THREAD_OPTION_CLONE
thread option, via the new QThreadOptions packet.

This shuffles code in linux_process_target::handle_extended_wait
around to a more logical order when we now have to handle and
potentially report all of fork/vfork/clone.

Raname lwp_info::fork_relative -> lwp_info::relative as the field is
no longer only about (v)fork.

With this, gdb.threads/stepi-over-clone.exp now cleanly passes against
GDBserver, so remove the native-target-only requirement from that
testcase.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27830
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I3a19bc98801ec31e5c6fdbe1ebe17df855142bb2

Thread options & clone events (native Linux)

This commit teaches the native Linux target about the
GDB_THREAD_OPTION_CLONE thread option. It's actually simpler to just
continue reporting all clone events unconditionally to the core.
There's never any harm in reporting a clone event when the option is
disabled. All we need to do is to report support for the option,
otherwise GDB falls back to use target_thread_events().

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27830
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: If90316e2dcd0c61d0fefa0d463c046011698acf9

Thread options & clone events (core + remote)

A previous patch taught GDB about a new TARGET_WAITKIND_THREAD_CLONED
event kind, and made the Linux target report clone events.

A following patch will teach Linux GDBserver to do the same thing.

However, for remote debugging, it wouldn't be ideal for GDBserver to
report every clone event to GDB, when GDB only cares about such events
in some specific situations.  Reporting clone events all the time
would be potentially chatty.  We don't enable thread create/exit
events all the time for the same reason.  Instead we have the
QThreadEvents packet.  QThreadEvents is target-wide, though.

This patch makes GDB instead explicitly request that the target
reports clone events or not, on a per-thread basis.

In order to be able to do that with GDBserver, we need a new remote
protocol feature.  Since a following patch will want to enable thread
exit events on per-thread basis too, the packet introduced here is
more generic than just for clone events.  It lets you enable/disable a
set of options at once, modelled on Linux ptrace's PTRACE_SETOPTIONS.

IOW, this commit introduces a new QThreadOptions packet, that lets you
specify a set of per-thread event options you want to enable.  The
packet accepts a list of options/thread-id pairs, similarly to vCont,
processed left to right, with the options field being a number
interpreted as a bit mask of options.  The only option defined in this
commit is GDB_THREAD_OPTION_CLONE (0x1), which ask the remote target
to report clone events.  Another patch later in the series will
introduce another option.

For example, this packet sets option "1" (clone events) on thread
p1000.2345:

  QThreadOptions;1:p1000.2345

and this clears options for all threads of process 1000, and then sets
option "1" (clone events) on thread p1000.2345:

  QThreadOptions;0:p1000.-1;1:p1000.2345

This clears options of all threads of all processes:

  QThreadOptions;0

The target reports the set of supported options by including
"QThreadOptions=<supported options>" in its qSupported response.

infrun is then tweaked to enable GDB_THREAD_OPTION_CLONE when stepping
over a breakpoint.

Unlike PTRACE_SETOPTIONS, fork/vfork/clone children do NOT inherit
their parent's thread options.  This is so that GDB can send e.g.,
"QThreadOptions;0;1:TID" without worrying about threads it doesn't
know about yet.

Documentation for this new remote protocol feature is included in a
documentation patch later in the series.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27830
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Ie41e5093b2573f14cf6ac41b0b5804eba75be37e

Avoid duplicate QThreadEvents packets

Similarly to QProgramSignals and QPassSignals, avoid sending duplicate
QThreadEvents packets.

Approved-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Iaf5babb0b64e1527ba4db31aac8674d82b17e8b4

Support clone events in the remote protocol

The previous patch taught GDB about a new
TARGET_WAITKIND_THREAD_CLONED event kind, and made the Linux target
report clone events.

A following patch will teach Linux GDBserver to do the same thing.

But before we get there, we need to teach the remote protocol about
TARGET_WAITKIND_THREAD_CLONED. That's what this patch does. Clone is
very similar to vfork and fork, and the new stop reply is likewise
handled similarly. The stub reports "T05clone:...".

GDBserver core is taught to handle TARGET_WAITKIND_THREAD_CLONED and
forward it to GDB in this patch, but no backend actually emits it yet.
That will be done in a following patch.

Documentation for this new remote protocol feature is included in a
documentation patch later in the series.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: If271f20320d864f074d8ac0d531cc1a323da847f
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27830

Step over clone syscall w/ breakpoint, TARGET_WAITKIND_THREAD_CLONED

(A good chunk of the problem statement in the commit log below is
Andrew's, adjusted for a different solution, and for covering
displaced stepping too.  The testcase is mostly Andrew's too.)

This commit addresses bugs gdb/19675 and gdb/27830, which are about
stepping over a breakpoint set at a clone syscall instruction, one is
about displaced stepping, and the other about in-line stepping.

Currently, when a new thread is created through a clone syscall, GDB
sets the new thread running.  With 'continue' this makes sense
(assuming no schedlock):

- all-stop mode, user issues 'continue', all threads are set running,
   a newly created thread should also be set running.

- non-stop mode, user issues 'continue', other pre-existing threads
   are not affected, but as the new thread is (sort-of) a child of the
   thread the user asked to run, it makes sense that the new threads
   should be created in the running state.

Similarly, if we are stopped at the clone syscall, and there's no
software breakpoint at this address, then the current behaviour is
fine:

- all-stop mode, user issues 'stepi', stepping will be done in place
   (as there's no breakpoint to step over).  While stepping the thread
   of interest all the other threads will be allowed to continue.  A
   newly created thread will be set running, and then stopped once the
   thread of interest has completed its step.

- non-stop mode, user issues 'stepi', stepping will be done in place
   (as there's no breakpoint to step over).  Other threads might be
   running or stopped, but as with the continue case above, the new
   thread will be created running.  The only possible issue here is
   that the new thread will be left running after the initial thread
   has completed its stepi.  The user would need to manually select
   the thread and interrupt it, this might not be what the user
   expects.  However, this is not something this commit tries to
   change.

The problem then is what happens when we try to step over a clone
syscall if there is a breakpoint at the syscall address.

- For both all-stop and non-stop modes, with in-line stepping:

   + user issues 'stepi',
   + [non-stop mode only] GDB stops all threads.  In all-stop mode all
     threads are already stopped.
   + GDB removes s/w breakpoint at syscall address,
   + GDB single steps just the thread of interest, all other threads
     are left stopped,
   + New thread is created running,
   + Initial thread completes its step,
   + [non-stop mode only] GDB resumes all threads that it previously
     stopped.

There are two problems in the in-line stepping scenario above:

  1. The new thread might pass through the same code that the initial
     thread is in (i.e. the clone syscall code), in which case it will
     fail to hit the breakpoint in clone as this was removed so the
     first thread can single step,

  2. The new thread might trigger some other stop event before the
     initial thread reports its step completion.  If this happens we
     end up triggering an assertion as GDB assumes that only the
     thread being stepped should stop.  The assert looks like this:

     infrun.c:5899: internal-error: int finish_step_over(execution_control_state*): Assertion `ecs->event_thread->control.trap_expected' failed.

- For both all-stop and non-stop modes, with displaced stepping:

   + user issues 'stepi',
   + GDB starts the displaced step, moves thread's PC to the
     out-of-line scratch pad, maybe adjusts registers,
   + GDB single steps the thread of interest, [non-stop mode only] all
     other threads are left as they were, either running or stopped.
     In all-stop, all other threads are left stopped.
   + New thread is created running,
   + Initial thread completes its step, GDB re-adjusts its PC,
     restores/releases scratchpad,
   + [non-stop mode only] GDB resumes the thread, now past its
     breakpoint.
   + [all-stop mode only] GDB resumes all threads.

There is one problem with the displaced stepping scenario above:

  3. When the parent thread completed its step, GDB adjusted its PC,
     but did not adjust the child's PC, thus that new child thread
     will continue execution in the scratch pad, invoking undefined
     behavior.  If you're lucky, you see a crash.  If unlucky, the
     inferior gets silently corrupted.

What is needed is for GDB to have more control over whether the new
thread is created running or not.  Issue #1 above requires that the
new thread not be allowed to run until the breakpoint has been
reinserted.  The only way to guarantee this is if the new thread is
held in a stopped state until the single step has completed.  Issue #3
above requires that GDB is informed of when a thread clones itself,
and of what is the child's ptid, so that GDB can fixup both the parent
and the child.

When looking for solutions to this problem I considered how GDB
handles fork/vfork as these have some of the same issues.  The main
difference between fork/vfork and clone is that the clone events are
not reported back to core GDB.  Instead, the clone event is handled
automatically in the target code and the child thread is immediately
set running.

Note we have support for requesting thread creation events out of the
target (TARGET_WAITKIND_THREAD_CREATED).  However, those are reported
for the new/child thread.  That would be sufficient to address in-line
stepping (issue #1), but not for displaced-stepping (issue #3).  To
handle displaced-stepping, we need an event that is reported to the
_parent_ of the clone, as the information about the displaced step is
associated with the clone parent.  TARGET_WAITKIND_THREAD_CREATED
includes no indication of which thread is the parent that spawned the
new child.  In fact, for some targets, like e.g., Windows, it would be
impossible to know which thread that was, as thread creation there
doesn't work by "cloning".

The solution implemented here is to model clone on fork/vfork, and
introduce a new TARGET_WAITKIND_THREAD_CLONED event.  This event is
similar to TARGET_WAITKIND_FORKED and TARGET_WAITKIND_VFORKED, except
that we end up with a new thread in the same process, instead of a new
thread of a new process.  Like FORKED and VFORKED, THREAD_CLONED
waitstatuses have a child_ptid property, and the child is held stopped
until GDB explicitly resumes it.  This addresses the in-line stepping
case (issues #1 and #2).

The infrun code that handles displaced stepping fixup for the child
after a fork/vfork event is thus reused for THREAD_CLONE, with some
minimal conditions added, addressing the displaced stepping case
(issue #3).

The native Linux backend is adjusted to unconditionally report
TARGET_WAITKIND_THREAD_CLONED events to the core.

Following the follow_fork model in core GDB, we introduce a
target_follow_clone target method, which is responsible for making the
new clone child visible to the rest of GDB.

Subsequent patches will add clone events support to the remote
protocol and gdbserver.

displaced_step_in_progress_thread becomes unused with this patch, but
a new use will reappear later in the series.  To avoid deleting it and
readding it back, this patch marks it with attribute unused, and the
latter patch removes the attribute again.  We need to do this because
the function is static, and with no callers, the compiler would warn,
(error with -Werror), breaking the build.

This adds a new gdb.threads/stepi-over-clone.exp testcase, which
exercises stepping over a clone syscall, with displaced stepping vs
inline stepping, and all-stop vs non-stop.  We already test stepping
over clone syscalls with gdb.base/step-over-syscall.exp, but this test
uses pthreads, while the other test uses raw clone, and this one is
more thorough.  The testcase passes on native GNU/Linux, but fails
against GDBserver.  GDBserver will be fixed by a later patch in the
series.

Co-authored-by: Andrew Burgess <aburgess@redhat.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27830
Change-Id: I95c06024736384ae8542a67ed9fdf6534c325c8e
Reviewed-By: Andrew Burgess <aburgess@redhat.com>

gdb/linux: Delete all other LWPs immediately on ptrace exec event

I noticed that on an Ubuntu 20.04 system, after a following patch
("Step over clone syscall w/ breakpoint,
TARGET_WAITKIND_THREAD_CLONED"), the gdb.threads/step-over-exec.exp
was passing cleanly, but still, we'd end up with four new unexpected
GDB core dumps:

=== gdb Summary ===

# of unexpected core files      4
# of expected passes            48

That said patch is making the pre-existing
gdb.threads/step-over-exec.exp testcase (almost silently) expose a
latent problem in gdb/linux-nat.c, resulting in a GDB crash when:

#1 - a non-leader thread execs
#2 - the post-exec program stops somewhere
#3 - you kill the inferior

Instead of #3 directly, the testcase just returns, which ends up in
gdb_exit, tearing down GDB, which kills the inferior, and is thus
equivalent to #3 above.

Vis (after said patch is applied):

$ gdb --args ./gdb /home/pedro/gdb/build/gdb/testsuite/outputs/gdb.threads/step-over-exec/step-over-exec-execr-thread-other-diff-text-segs-true
...
(top-gdb) r
...
(gdb) b main
...
(gdb) r
...
Breakpoint 1, main (argc=1, argv=0x7fffffffdb88) at /home/pedro/gdb/build/gdb/testsuite/../../../src/gdb/testsuite/gdb.threads/step-over-exec.c:69
69        argv0 = argv[0];
(gdb) c
Continuing.
[New Thread 0x7ffff7d89700 (LWP 2506975)]
Other going in exec.
Exec-ing /home/pedro/gdb/build/gdb/testsuite/outputs/gdb.threads/step-over-exec/step-over-exec-execr-thread-other-diff-text-segs-true-execd
process 2506769 is executing new program: /home/pedro/gdb/build/gdb/testsuite/outputs/gdb.threads/step-over-exec/step-over-exec-execr-thread-other-diff-text-segs-true-execd

Thread 1 "step-over-exec-" hit Breakpoint 1, main () at /home/pedro/gdb/build/gdb/testsuite/../../../src/gdb/testsuite/gdb.threads/step-over-exec-execd.c:28
28        foo ();
(gdb) k
...
Thread 1 "gdb" received signal SIGSEGV, Segmentation fault.
0x000055555574444c in thread_info::has_pending_waitstatus (this=0x0) at ../../src/gdb/gdbthread.h:393
393         return m_suspend.waitstatus_pending_p;
(top-gdb) bt
#0  0x000055555574444c in thread_info::has_pending_waitstatus (this=0x0) at ../../src/gdb/gdbthread.h:393
#1  0x0000555555a884d1 in get_pending_child_status (lp=0x5555579b8230, ws=0x7fffffffd130) at ../../src/gdb/linux-nat.c:1345
#2  0x0000555555a8e5e6 in kill_unfollowed_child_callback (lp=0x5555579b8230) at ../../src/gdb/linux-nat.c:3564
#3  0x0000555555a92a26 in gdb::function_view<int (lwp_info*)>::bind<int, lwp_info*>(int (*)(lwp_info*))::{lambda(gdb::fv_detail::erased_callable, lwp_info*)#1}::operator()(gdb::fv_detail::erased_callable, lwp_info*) const (this=0x0, ecall=..., args#0=0x5555579b8230) at ../../src/gdb/../gdbsupport/function-view.h:284
#4  0x0000555555a92a51 in gdb::function_view<int (lwp_info*)>::bind<int, lwp_info*>(int (*)(lwp_info*))::{lambda(gdb::fv_detail::erased_callable, lwp_info*)#1}::_FUN(gdb::fv_detail::erased_callable, lwp_info*) () at ../../src/gdb/../gdbsupport/function-view.h:278
#5  0x0000555555a91f84 in gdb::function_view<int (lwp_info*)>::operator()(lwp_info*) const (this=0x7fffffffd210, args#0=0x5555579b8230) at ../../src/gdb/../gdbsupport/function-view.h:247
#6  0x0000555555a87072 in iterate_over_lwps(ptid_t, gdb::function_view<int (lwp_info*)>) (filter=..., callback=...) at ../../src/gdb/linux-nat.c:864
#7  0x0000555555a8e732 in linux_nat_target::kill (this=0x55555653af40 <the_amd64_linux_nat_target>) at ../../src/gdb/linux-nat.c:3590
#8  0x0000555555cfdc11 in target_kill () at ../../src/gdb/target.c:911
...

The root of the problem is that when a non-leader LWP execs, it just
changes its tid to the tgid, replacing the pre-exec leader thread,
becoming the new leader.  There's no thread exit event for the execing
thread.  It's as if the old pre-exec LWP vanishes without trace.  The
ptrace man page says:

"PTRACE_O_TRACEEXEC (since Linux 2.5.46)
Stop the tracee at the next execve(2).  A waitpid(2) by the
tracer will return a status value such that

  status>>8 == (SIGTRAP | (PTRACE_EVENT_EXEC<<8))

If the execing thread is not a thread group leader, the thread
ID is reset to thread group leader's ID before this stop.
Since Linux 3.0, the former thread ID can be retrieved with
PTRACE_GETEVENTMSG."

When the core of GDB processes an exec events, it deletes all the
threads of the inferior.  But, that is too late -- deleting the thread
does not delete the corresponding LWP, so we end leaving the pre-exec
non-leader LWP stale in the LWP list.  That's what leads to the crash
above -- linux_nat_target::kill iterates over all LWPs, and after the
patch in question, that code will look for the corresponding
thread_info for each LWP.  For the pre-exec non-leader LWP still
listed, won't find one.

This patch fixes it, by deleting the pre-exec non-leader LWP (and
thread) from the LWP/thread lists as soon as we get an exec event out
of ptrace.

GDBserver does not need an equivalent fix, because it is already doing
this, as side effect of mourning the pre-exec process, in
gdbserver/linux-low.cc:

  else if (event == PTRACE_EVENT_EXEC && cs.report_exec_events)
    {
...
      /* Delete the execing process and all its threads.  */
      mourn (proc);
      switch_to_thread (nullptr);

The crash with gdb.threads/step-over-exec.exp is not observable on
newer systems, which postdate the glibc change to move "libpthread.so"
internals to "libc.so.6", because right after the exec, GDB traps a
load event for "libc.so.6", which leads to GDB trying to open
libthread_db for the post-exec inferior, and, on such systems that
succeeds.  When we load libthread_db, we call
linux_stop_and_wait_all_lwps, which, as the name suggests, stops all
lwps, and then waits to see their stops.  While doing this, GDB
detects that the pre-exec stale LWP is gone, and deletes it.

If we use "catch exec" to stop right at the exec before the
"libc.so.6" load event ever happens, and issue "kill" right there,
then GDB crashes on newer systems as well.  So instead of tweaking
gdb.threads/step-over-exec.exp to cover the fix, add a new
gdb.threads/threads-after-exec.exp testcase that uses "catch exec".
The test also uses the new "maint info linux-lwps" command if testing
on Linux native, which also exposes the stale LWP problem with an
unfixed GDB.

Also tweak a comment in infrun.c:follow_exec referring to how
linux-nat.c used to behave, as it would become stale otherwise.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I21ec18072c7750f3a972160ae6b9e46590376643

Add "maint info linux-lwps" command

This adds a maintenance command that lets you list all the LWPs under
control of the linux-nat target.

For example:

(gdb) maint info linux-lwps
LWP Ptid Thread ID
560948.561047.0 None
560948.560948.0 1.1

This shows that "560948.561047.0" LWP doesn't map to any thread_info
object, which is bogus. We'll be using this in a testcase in a
following patch.

Co-Authored-By: Pedro Alves <pedro@palves.net>
Change-Id: Ic4e9e123385976e5cd054391990124b7a20fb3f5

[gdb/tui] Fix Wmaybe-uninitialized in tui_find_disassembly_address

When building gdb with -O2, we run into:
...
gdb/tui/tui-disasm.c: In function ‘CORE_ADDR tui_find_disassembly_address \
  (gdbarch*, CORE_ADDR, int)’:
gdb/tui/tui-disasm.c:293:7: warning: ‘last_addr’ may be used uninitialized \
  in this function [-Wmaybe-uninitialized]
       if (last_addr < pc)
       ^~
...

The warning triggers since commit 72535eb14bd ("[gdb/tui] Fix segfault in
tui_find_disassembly_address").

Fix the warning by ensuring that last_addr is initialized at the point of
use:
...
+      last_addr = asm_lines.back ().addr;
       if (last_addr < pc)
...

Tested on x86_64-linux.

[gdb/tui] Make assert in tui_find_disassembly_address more strict

In tui_find_disassembly_address we find an assert:
...
      if (asm_lines.size () < max_lines)
{
  if (!possible_new_low.has_value ())
    return new_low;

  /* Take the best possible match we have.  */
  new_low = *possible_new_low;
  next_addr = tui_disassemble (gdbarch, asm_lines, new_low, max_lines);
  last_addr = asm_lines.back ().addr;
  gdb_assert (asm_lines.size () >= max_lines);
}
...

The comment right above:
...
      /* If we failed to disassemble the required number of lines then the
following walk forward is not going to work, it assumes that
ASM_LINES contains exactly MAX_LINES entries.  Instead we should
consider falling back to a previous possible start address in
POSSIBLE_NEW_LOW.  */
...
claims that the more strict asm_lines.size () == max_line is required.

Update the assert to reflect this, and move it to after the if because it's
supposed to hold in general, not just when entering the if.

Tested on x86_64-linux.

Remove declaration of re_comp

defs.h declares re_comp, but it shouldn't. If this is needed, it
should be picked up from xregex.h via gdb_regex.h.

Tested by rebuilding.

Reviewed-by: Kevin Buettner <kevinb@redhat.com>

Automatic date update in version.in

bfd, binutils: add gfx11 amdgpu architectures

Teach bfd and readelf about some recent gfx11 architectures. This code
is taken from the rocgdb 5.7.x branch [1].

[1] https://github.com/rocm-Developer-Tools/rocgdb/tree/rocm-5.7.x

bfd/ChangeLog:

* archures.c (bfd_mach_amdgcn_gfx1100, bfd_mach_amdgcn_gfx1101,
bfd_mach_amdgcn_gfx1102): New.
* bfd-in2.h (bfd_mach_amdgcn_gfx1100, bfd_mach_amdgcn_gfx1101,
bfd_mach_amdgcn_gfx1102): New.
* cpu-amdgcn.c (arch_info_struct): Add entries for
bfd_mach_amdgcn_gfx1100, bfd_mach_amdgcn_gfx1101,
bfd_mach_amdgcn_gfx1102.

binutils/ChangeLog:

* readelf.c (decode_AMDGPU_machine_flags): Handle gfx1100,
gfx1101, gfx1102.

include/ChangeLog:

* elf/amdgpu.h (EF_AMDGPU_MACH_AMDGCN_GFX1100,
EF_AMDGPU_MACH_AMDGCN_GFX1101,
EF_AMDGPU_MACH_AMDGCN_GFX1102): New.

Change-Id: I95a8a62942e359781a1c9fa2079950fbcf2a78b8
Co-Authored-By: Laurent Morichetti <laurent.morichetti@amd.com>
Cc: Lancelot Six <lancelot.six@amd.com>

Correct formatting errors in elf32-microblaze.c

Signed-off-by: Michael J. Eager <eager@eagercon.com>

Gold/MIPS: Use EM_MIPS instead of EM_MIPS_RS3_LE for little endian

GAS/MIPS: Fix testcase module-defer-warn2 for r2+ triples

readelf..debug-dump=loc displays bogus base addresses

PR 30880
* dwarf.c (read_and_display_attr_value): Fix loclist handling. (display_loclists_list): Likewise.

GAS/MIPS: Add mips16-e-irix.d testcase

MIPS: Change all E_MIPS_* to EF_MIPS_*

Add ability to change linker warning messages into errors when reporting executable stacks and/or executable segments.

  include
  * bfdlink.h (struct bfd_link_info): Update descriptions of the 'execstack', 'noexecstack' and 'warn_execstack' fields. Add 'error_exectack' and 'warn_is_error_for_rwx_segments' fields.

  bfd
  * elf.c (assign_file_positions_except_relocs): Turn warnings about executable segments into errors if so requested.
  * elflink.c (bfd_elf_size_dynamic_sections): Turn warnings about executable stacks into errors if so requested.

  ld
  * ldlex.h (enum option_values): Add OPTION_ERROR_EXECSTACK, OPTION_NO_ERROR_EXECSTACK, OPTION_WARN_EXECSTACK_OBJECTS, OPTION_ERROR_RWX_SEGMENTS and OPTION_NO_ERROR_RWX_SEGMENTS. (struct ld_option): Add new long options. (parse_args): Parse new long options. (elf_static_list_options): Display the new options.
  * ld.texi: Document the new command line options.
  * configure.ac (error-execstack): New configuration option. (error-rwx-segments): New configuration option.
  * emultempl/elf.em (_before_parse): Initialse the new linkinfo fields.
  * NEWS: Mention the new features.
  * config.in: Regenerate.
  * configure: Regenerate.
  * testsuite/ld-elf/commonpage2.d: Disable errors for RWX segments and/or executable stacks.
  * testsuite/ld-elf/elf.exp: Likewise.
  * testsuite/ld-elf/header.d: Likewise.
  * testsuite/ld-elf/loadaddr1.d: Likewise.
  * testsuite/ld-elf/loadaddr2.d: Likewise.
  * testsuite/ld-elf/maxpage4.d: Likewise.
  * testsuite/ld-elf/nobits-1.d: Likewise.
  * testsuite/ld-elf/note-1.d: Likewise.
  * testsuite/ld-elf/orphan-10.d: Likewise.
  * testsuite/ld-elf/orphan-11.d: Likewise.
  * testsuite/ld-elf/orphan-12.d: Likewise.
  * testsuite/ld-elf/orphan-5.d: Likewise.
  * testsuite/ld-elf/orphan-7.d: Likewise.
  * testsuite/ld-elf/orphan-8.d: Likewise.
  * testsuite/ld-elf/orphan-9.d: Likewise.
  * testsuite/ld-elf/orphan-region.d: Likewise.
  * testsuite/ld-elf/orphan.d: Likewise.
  * testsuite/ld-elf/pr19539.d: Likewise.
  * testsuite/ld-elf/pr26256-1a.d: Likewise.
  * testsuite/ld-elf/pr26907.d: Likewise.
  * testsuite/ld-elf/pr28597.d: Likewise.
  * testsuite/ld-elf/retain2.d: Likewise.
  * testsuite/ld-elf/shared.exp: Likewise.
  * testsuite/ld-elf/size-1.d: Likewise.
  * testsuite/ld-elf/textaddr7.d: Likewise.
  * testsuite/ld-elf/warn1.d: Likewise.
  * testsuite/ld-elf/warn2.d: Likewise.
  * testsuite/ld-i386/discarded1.d: Likewise.
  * testsuite/ld-i386/pr19175.d: Likewise.
  * testsuite/ld-i386/pr19539.d: Likewise.
  * testsuite/ld-i386/pr23189.d: Likewise.
  * testsuite/ld-plugin/lto-3r.d: Likewise.
  * testsuite/ld-plugin/lto-5r.d: Likewise.
  * testsuite/ld-plugin/lto.exp: Likewise.
  * testsuite/ld-powerpc/ppc476-shared.d: Likewise.
  * testsuite/ld-powerpc/ppc476-shared2.d: Likewise.
  * testsuite/ld-powerpc/pr28827-2.d: Likewise.
  * testsuite/ld-s390/s390.exp: Likewise.
  * testsuite/ld-scripts/align2a.d: Likewise.
  * testsuite/ld-scripts/align2b.d: Likewise.
  * testsuite/ld-scripts/align5.d: Likewise.
  * testsuite/ld-scripts/alignof.exp: Likewise.
  * testsuite/ld-scripts/crossref.exp: Likewise.
  * testsuite/ld-scripts/defined2.d: Likewise.
  * testsuite/ld-scripts/defined3.d: Likewise.
  * testsuite/ld-scripts/defined5.d: Likewise.
  * testsuite/ld-scripts/pr14962.d: Likewise.
  * testsuite/ld-scripts/pr18963.d: Likewise.
  * testsuite/ld-scripts/pr20302.d: Likewise.
  * testsuite/ld-scripts/print-memory-usage.exp: Likewise.
  * testsuite/ld-scripts/rgn-at1.d: Likewise.
  * testsuite/ld-scripts/rgn-at10.d: Likewise.
  * testsuite/ld-scripts/rgn-at4.d: Likewise.
  * testsuite/ld-scripts/rgn-at6.d: Likewise.
  * testsuite/ld-scripts/rgn-at8.d: Likewise.
  * testsuite/ld-scripts/rgn-at9.d: Likewise.
  * testsuite/ld-scripts/rgn-over1.d: Likewise.
  * testsuite/ld-scripts/rgn-over2.d: Likewise.
  * testsuite/ld-scripts/rgn-over4.d: Likewise.
  * testsuite/ld-scripts/rgn-over5.d: Likewise.
  * testsuite/ld-scripts/rgn-over6.d: Likewise.
  * testsuite/ld-scripts/script.exp: Likewise.
  * testsuite/ld-scripts/sizeof.exp: Likewise.
  * testsuite/ld-scripts/sort-file.d: Likewise.
  * testsuite/ld-x86-64/discarded1.d: Likewise.
  * testsuite/ld-x86-64/pr19175.d: Likewise.
  * testsuite/ld-x86-64/pr19539a.d: Likewise.
  * testsuite/ld-x86-64/pr19539b.d: Likewise.
  * testsuite/ld-x86-64/pr23189.d: Likewise.

Move new features above the 'Changes in 2.41' comment

Add support for ilp32 register alias.

Automatic date update in version.in

bfd: use less memory in string merging

the offset-to-entry mappings are allocated in blocks, which may
become a bit wasteful in case there are extremely many small
input files or sections.  This made it so that a large project
(Qt5WebEngine) didn't build anymore on x86 32bit due to address
space limits.  It barely fit into address space before the new
string merging, and then got pushed over the limit by this.

So instead of leaving the waste reallocate the maps to their final
size once known.  Now the link barely fits again.

bfd/
    * merge.c (record_section): Reallocate offset maps to their
    final size.

ld: Avoid overflows in string merging

as the bug report shows we had an overflow in the test if
hash table resizing is needed.  Reorder the expression to avoid
that.  There's still a bug somewhere in gracefully handling
failure in resizing (e.g. out of memory), but this pushes the
boundary for that occurring somewhen into the future and
immediately helps the reporter.

    bfd/

    PR ld/31009
    * merge.c (NEEDS_RESIZE): New macro avoiding overflow.
    (sec_merge_maybe_resize): Use it.
    (sec_merge_hash_insert): Ditto.

ld: aarch64: Use lp64 abi in recent BTI stub tests

The tests are not compatible with ilp32 abi: the GNU property
note is ABI dependent (size changes) and the disasm is ABI
dependent too. Making the test portable between the ABIs is
not trivial.

For now force lp64 abi.

ld: aarch64: Add BTI stub insertion test PR30930

The test creates a large shared library and covers a number of
BTI stub insertion cases.

bfd: aarch64: Avoid BTI stub for a PLT that has BTI

We decide to emit BTI stubs based on the instruction at the target
location. But PLT code is generated later than the stubs so we always
read 0 which is not a valid BTI.

Fix the logic to special case the PLT section: this is code the linker
generates so we know when it will have BTI.

This avoids BTI stubs in large executables where the PLTs have them
already. An alternative is to never emit BTI stubs for PLTs, instead
use BTI in the PLT if a library gets too big, however that may be
more tricky given the ordering of PLT sizing and stub insertion.

Related to bug 30957.

bfd: aarch64: Fix leaks in case of BTI stub reuse

BTI stub parameters were recomputed even if those were already set up.
This is unnecessary work and leaks the symbol name that is allocated
for the stub.

bfd: aarch64: Fix broken BTI stub PR30930

Input sections are grouped together that can use the same stub area
(within reach) and these groups have a stable id.

Stubs have a name generated from the stub group id and target symbol.
When a relocation requires a stub with a name that already exists, the
stub is reused instead of adding a new one.

For an indirect branch stub another BTI stub may be inserted near the
target to provide a BTI landing pad.

The BTI stub can end up with the same stub group id and thus the same
name as the indirect stub. This happens if the target symbol is within
reach of the indirect branch stub. Then, due to the name collision,
only a single stub was emmitted which branched to itself causing an
infinite loop at runtime.

A possible solution is to just name the BTI stubs differently, but
since in the problematic case the indirect and BTI stub are in the
same stub area, a better solution is to emit a single stub with a
direct branch. The stub is still needed since the caller cannot reach
the target directly and we also want a BTI landing pad in the stub in
case other indirect stubs target the same symbol and thus need a BTI
stub.

In short we convert an indirect branch stub into a BTI stub when the
target is within reach and has no BTI. It is a hassle to change the
symbol of the stub so a BTI stub may end up with *_veneer instead of
*_bti_veneer after the conversion, but this should not matter much.
(Refactoring some of _bfd_aarch64_add_call_stub_entries would be
useful but too much for this bug fix patch.)

The same conversion to direct branch could be done even if the target
did not need a BTI. The stub groups are fixed in the current logic so
linking can fail if too many stubs are inserted and the section layout
is changed too much, but this only happens in extreme cases that can
be reasonably ignored. Because of this the target cannot go out of
reach during stub insertion so the optimization is valid, but not
implemented by this patch for the non-BTI case.

Fixes bug 30930.

bfd: aarch64: Fix BTI stub optimization PR30957

The instruction was looked up in the wrong input file (file of branch
source instead of branch target) when optimizing away BTI stubs in

commit 5834f36d93cabf1a8bcc7dd7654141aed3d296bc
bfd: aarch64: Optimize BTI stubs PR30076

This can cause adding BTI stubs when they are not necessary or removing
them when they are (the latter is a correctness issue but it is very
unlikely in practice).

Fixes bug 30957.

aarch64: Fix error in THE system register checking

The erroneous omission of a "reg_value == " in the THE system register
encoding check added in [1] led to an error which was not picked up in
GCC but which was flagged in Clang due to its use of
[-Werror,-Wconstant-logical-operand] check. Together with this fix we
add a new test for the THE registers to pick up their illegal use,
adding an extra and important layer of validation.

Furthermore, in separating system register from instruction
implementation (with which only the former was of concern in the cited
patch), additions made to `aarch64-tbl.h' are rolled back so
that these can be added later when adding THE instructions to the
codebase, a more natural place for these changes.

[1] https://sourceware.org/pipermail/binutils/2023-November/130314.html

opcodes/ChangeLog:

* aarch64-opc.c (aarch64_sys_ins_reg_supported_p): Fix typo.
* aarch64-tbl.h (THE): Remove.
(aarch64_feature_set aarch64_feature_the): Likewise.

gas/ChangeLog:

* testsuite/gas/aarch64/illegal-sysreg-8.l: Add tests for THE
system registers.
* testsuite/gas/aarch64/illegal-sysreg-8.s: Likewise.

x86: rework UWRMSR operand swapping

As indicated during review already, doing the swapping early is overall
cheaper than doing it only after operand matching.

x86: do away with is_evex_encoding()

As we have grown more uses of it, it becomes increasingly more desirable
to replace it by a simpler check. Have i386-gen do at build time what so
far was done at runtime: Deal with templates indicating EVEX-encoding by
other than the EVex attribute, and set that to "dynamic" in such cases.

This then allows simplifying a number of other conditionals as well.

x86: split insn templates' CPU field

Right now the opcode table has entries with ISA restrictions of the form
FEAT1|FEAT2, the meaning of which depends on context and requires
special treatment in tc-i386.c: Sometimes this means "both features
requires", whereas originally it was intended to solely mean "all of
these features required". Split the field, with the original one
regaining its original meaning. The new field now truly means "any of
these". The combination of both fields is still and &&-type check, i.e.
(all of these) && (any of these). In the opcode table more involved
combinations of features then also need expressing this way: "all"
entities first, follow by "any" entities enclosed in parentheses, e.g.
x64&(AVX|AVX512F). If the "all" part is empty, parentheses may not be
added around the "any" part (unless parsing logic was further relaxed).

Note that this way AVX512VL no longer needs as much special treatment,
and hence templates previously using AVX512F|AVX512VL are switched to
just AVX512VL.

Note further that this requires FMA handling as resulting from
da0784f961d8 ("x86: fold FMA VEX and EVEX templates") to be slightly
re-done: FMA now becomes more similar to AVX and AVX2.

x86: Cpu64 handling improvements

First of all we want to also accumulate its reverse dependencies, such
that we can use them in cpu_flags_match(). This is in particular in
preparation of APX additions, such that e.g. BMI VEX-encoding templates
can become combined VEX/EVEX ones.

Once we have the reverse dependencies, we can further leverage them to
omit explicit "&x64" from any insn templates dealing with 64-bit-mode-
only ISA extensions. Besides helping readability for several insn
templates we already have, this will also help with what is going to be
added for APX (as all of the new templates would otherwise need to have
"&x64").

Note that rather than leaving a meaningless CPU_64_FLAGS (which is
unused anyway), its emitting is now also suppressed.

x86: Intel Core processors do not support CMPXCHG16B

This being a 64-bit-only instruction (see also i386-opc.tbl) it cannot
possibly be supported by CPUs not supporting 64-bit mode.

Automatic date update in version.in

rs6000, Fix test gdb.base/store.exp

The test currently fails for IEEE 128-bit floating point types.  PowerPC
supports the IBM double 128-bit floating point format and IEEE 128-bit
format.  The IBM double 128-bit floating point format uses two 64-bit
floating point registers to store the 128-bit value.  The IEEE 128-bit
floating point format stores the value in a single 128-bit vector-scalar
register (vsr).

The various floating point values, 32-bit float, 64-bit double, IBM double
128-bit float and IEEE 128-bit floating point numbers are all mapped to the
DWARF fpr numbers.  The issue is the IEEE 128-bit floating point values are
actually stored in a vsr not the fprs.  This patch changes the register
mapping for the vsrs from the fpr to the vsr registers so the value is
properly accessed by GDB.  The functions rs6000_linux_register_to_value,
rs6000_linux_value_to_register, rs6000_linux_value_from_register check if
the value is an IEEE 128-bit floating point value and adjust the register
number as needed.  The test in function rs6000_convert_register_p is fixed
so it is only true for floating point values.

This patch fixes three regression tests in gdb.base/store.exp.

The patch has been tested on Power 8 LE/BE, Power 9 LE/BE and Power 10 LE
with no regressions.

rs6000, Fix Linux DWARF register mapping

Overview of issues fixed by the patch.

The primary issue this patch fixes is the DWARF register mapping for
Linux.  The changes in ppc-linux-tdep.c fix the DWARF register mapping
issues.  The register mapping issue is responsible for two of the
five regression bugs seen in gdb.base/store.exp.

Once the register mapping was fixed, an underlying issue with the unwinding
of the signal trampoline in common-code in ifrun.c was found.  This
underlying bug is best described by Ulrich in the following description.

  The unwinder bug shows up on platforms where the kernel uses a trampoline
  to dispatch "calls to" the signal handler (not just *returns from* the
  signal handler).  Many platforms use a trampoline for signal return, and
  that is working fine, but the only platform I'm (Ulrich) aware of that
  uses a trampoline for signal handler calls is (recent kernels for)
  PowerPC.  I believe the rationale for using a trampoline here
  is to improve performance by avoiding unbalancing of the
  branch predictor's call/return stack.

  However, on PowerPC the bug is dormant as well as it is hidden
  by *another* bug that prevents correct unwinding out of the
  signal trampoline.  This is because the custom CFI for the
  trampoline uses a register number (VSCR) that is not ever used
  by compiler-generated CFI, and that particular register is
  mapped to an invalid number by the current PowerPC DWARF mapper.

The underlying unwinder bug is exposed by the "new" regression failures
in gdb.base/sigstep.exp.  These failures were previously masked by
the fact that GDB was not seeing a valid frame when it tried to unwind
the frames.  The sigstep.exp test is specifically testing stepping into
a signal handler.  With the correct DWARF register mapping in place,
specifically the VSCR mapping, the signal trampoline code now unwinds to a
valid frame exposing the pre-existing bug in how the signal handler on
PowerPC works.  The one line change infrun.c fixes the exiting bug in
the common-code for platforms that use a trampoline to dispatch calls
to the signal handler by not stopping in the SIGTRAMP_FRAME.

Detailed description of the DWARF register mapping fix.

The PowerPC DWARF register mapping is the same for the .eh_frame and
.debug_frame on Linux.  PowerPC uses different mapping for .eh_frame and
.debug_frame on other operating systems.  The current GDB support for
mapping the DWARF registers in rs6000_linux_dwarf2_reg_to_regnum and
rs6000_adjust_frame_regnum file gdb/rs6000-tdep.c is not correct for Linux.
The files have some legacy mappings for spe_acc, spefscr, EV which was
removed from GCC in 2017.

This patch adds a two new functions rs6000_linux_dwarf2_reg_to_regnum,
and rs6000_linux_adjust_frame_regnum in file gdb/ppc-linux-tdep.c to handle
the DWARF register mappings on Linux.  Function
rs6000_linux_dwarf2_reg_to_regnum is installed for both gdb_dwarf_to_regnum
and gdbarch_stab_reg_to_regnum since the mappings are the same.

The ppc_linux_init_abi function in gdb/ppc-linux-tdep.c is updated to
call set_gdbarch_dwarf2_reg_to_regnum map the new function
rs6000_linux_dwarf2_reg_to_regnum for the architecture.  Similarly,
dwarf2_frame_set_adjust_regnum is called to map
rs6000_linux_adjust_frame_regnum into the architecture.

Additional detail on the signal handling fix.

The specific sequence of events for handling a signal on most
architectures is as follows:

  1) Some code is running when a signal arrives.
  2) The kernel handles the signal and dispatches to the handler.
    ...

However on PowerPC the sequence of events is:

  1) Some code is running when a signal arrives.
  2) The kernel handles the signal and dispatches to the trampoline.
  3) The trampoline performs a normal function call to the handler.
      ...

We want the "nexti" to step into, not over, signal handlers invoked by
the kernel.  This is the case for most platforms as the kernel puts a
signal trampoline frame onto the stack to handle proper return after the
handler.  However, on some platforms such as PowerPC, the kernel actually
uses a trampoline to handle *invocation* of the handler.  We do not
want GDB to stop in the SIGTRAMP_FRAME.  The issue is fixed in function
process_event_stop_test by adding a check that the frame is not a
SIGTRAMP_FRAME to the if statement to stop in a subroutine call.  This
prevents GDB from erroneously detecting the trampoline invocation as a
subroutine call.

This patch fixes two regression test failures in gdb.base/store.exp.

The patch then fixes an exposed, dormant, signal handling issue that
is exposed in the signal handling test gdb.base/sigstep.exp.

The patch has been tested on Power 8 LE/BE, Power 9 LE/BE, Power 10 with
no new regressions.  Note, only two of the five failures in store.exp
are fixed.  The remaining three failures are fixed in a following
patch.

gdb: call update_thread_list after completing an inferior call

I noticed that if GDB is using a remote or extended-remote target,
then, if an inferior call caused a new thread to appear, or for an
existing thread to exit, then these events are not reported to the
user.

The problem is that for these targets GDB relies on a call to
update_thread_list to learn about changes to the inferior's thread
list.

If GDB doesn't pass through the normal stop code then GDB will not
call update_thread_list, and so will not report changes in the thread
list.

This commit adds an additional update_thread_list call, after which
thread events are correctly reported.

gdb: call update_thread_list for $_inferior_thread_count function

I noticed that sometimes the value returned by $_inferior_thread_count
can become out of sync with the actual thread count of the inferior,
and will disagree with the number of threads reported by 'info
threads'.  This commit fixes this issue.

The cause of the problem is that 'info threads' includes a call to
update_thread_list, this can be seen in print_thread_info_1 in
thread.c, while $_inferior_thread_count doesn't include a similar
call, see the function inferior_thread_count_make_value also in
thread.c.

Of course, this is only a problem when GDB is running on a target that
relies on update_thread_list calls to learn about new threads,
e.g. remote or extended-remote targets.  Native targets generally
learn about new threads as soon as they appear and will not have this
problem.

I ran into this issue when writing a test for the next commit which
uses inferior function calls to add an remove threads from an
inferior.  But for testing I've made use of non-stop mode and
asynchronous inferior execution; by reading the inferior state I can
know when a new thread has been created, at which point I can print
$_inferior_thread_count while the inferior is still running.  This is
important, if I stop the inferior then GDB will pass through an
update_thread_list call in the normal stop code, which will
synchronise the thread list, after which $_inferior_thread_count will
report the correct value.

With this change in place $_inferior_thread_count is now correct.

gdb: add a custom command completer for disassemble command

Add a new command completer function for the disassemble command.
There are two things that this completion function changes.  First,
after the previous commit, the new function calls skip_over_slash_fmt,
which means that hitting tab after entering a /OPT flag now inserts a
space ready to start typing the address to disassemble at:

  (gdb) disassemble /r<TAB>
  (gdb) disassemble /r <CURSOR>

But also, we now get symbol completion after a /OPT option set,
previously this would do nothing:

  (gdb) disassemble /r mai<TAB>

But now:

  (gdb) disassemble /r mai<TAB>
  (gdb) disassemble /r main <CURSOR>

Which was my main motivation for working on this commit.

However, I have made a second change in the completion function.
Currently, the disassemble command calls the generic
location_completer function, however, the disassemble docs say:

     Note that the 'disassemble' command's address arguments are specified
  using expressions in your programming language (*note Expressions:
  Expressions.), not location specs (*note Location Specifications::).
  So, for example, if you want to disassemble function 'bar' in file
  'foo.c', you must type 'disassemble 'foo.c'::bar' and not 'disassemble
  foo.c:bar'.

And indeed, if I try:

  (gdb) disassemble hello.c:main
  No symbol "hello" in current context.
  (gdb) disassemble hello.c::main
  No symbol "hello" in current context.
  (gdb) disassemble 'hello.c'::main
  Dump of assembler code for function main:
  ... snip ...

But, if I do this:

  (gdb) disassemble hell<TAB>
  (gdb) disassemble hello.c:<CURSOR>

which is a consequence of using the location_completer function.  So
in this commit, after calling skip_over_slash_fmt, I forward the bulk
of the disassemble command completion to expression_completer.  Now
when I try this:

  (gdb) disassemble hell<TAB>

gives nothing, which I think is an improvement.  There is one slight
disappointment, if I do:

  (gdb) disassemble 'hell<TAB>

I still get nothing.  I had hoped that this would expand to:
'hello.c':: but I guess this is a limitation of the current
expression_completer implementation, however, I don't think this is a
regression, the previous expansion was just wrong.  Fixing
expression_completer is out of scope for this commit.

I've added some disassembler command completion tests, and also a test
that disassembling using 'FILE'::FUNC syntax works, as I don't think
that is tested anywhere.

gdb: make skip_over_slash_fmt available outside printcmd.c

Move the function skip_over_slash_fmt into completer.c, and make it
extern, with a declaration in completer.h.

This is a refactor in order to support the next commit. I've not
changed any of the code in skip_over_slash_fmt.

There should be no user visible changes after this commit.

gdb: error if /r and /b are used with disassemble command

The disassembler gained a new /b flag in this commit:

  commit d4ce49b7ac077a9882d6a5e689e260300045ca88
  Date:   Tue Jun 21 20:23:35 2022 +0100

      gdb: disassembler opcode display formatting

The /b and /r flags result in the instruction opcodes displayed in
different formats, so it's not possible to have both at the same
time.  Currently the /b flag overrides the /r flag.

We have a similar situation with the /m and /s flags, but here, if the
user tries to use both flags then they will get an error.

I think the error is clearer, so in this commit I propose that we add
an error if /r and /b are both used.

Obviously this change breaks backwards compatibility.  I don't have a
compelling argument for why we should make the change beyond my
feeling that it was a mistake not to add this error from the start,
and that the new behaviour is better.

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

gas: S_GET_{NAME,SEGMENT}() don't alter their input symbol

Make their parameters pointer-to-const, thus allowing callers to also be
const-correct where possible.

ld: print branch fixups into the map file for ppc elf targets

In a safety context, it could interesting to track the trampolines being
generated, ensuring there are expected or not.

bfd/ChangeLog:

* elf32-ppc.c (ppc_elf_relax_section): Log branch fixups.

ld/ChangeLog:

* ld.texi (--print-map): Add new item about fixups.

Add minimal thread-safety to BFD

This patch provides some minimal thread-safety to BFD.

The BFD client can request thread-safety by providing a lock and
unlock function.  The globals used during BFD creation (e.g.,
bfd_id_counter) are then locked, and the file descriptor cache is also
locked.  A function to clean up any thread-local data is now provided
for BFD clients.

* bfd-in2.h: Regenerate.
* bfd.c (lock_fn, unlock_fn): New globals.
(bfd_thread_init, bfd_thread_cleanup, bfd_lock, bfd_unlock): New
functions.
* cache.c (bfd_cache_lookup_worker): Use _bfd_open_file_unlocked.
(cache_btell, cache_bseek, cache_bread, cache_bwrite): Lock
and unlock.
(cache_bclose): Add comment.
(cache_bflush, cache_bstat, cache_bmmap): Lock and unlock.
(_bfd_cache_init_unlocked): New function.
(bfd_cache_init): Use it.  Lock and unlock.
(_bfd_cache_close_unlocked): New function.
(bfd_cache_close, bfd_cache_close_all): Use it.  Lock and unlock.
(_bfd_open_file_unlocked): New function.
(bfd_open_file): Use it.  Lock and unlock.
* doc/bfd.texi (BFD front end): Add Threading menu item.
* libbfd.h: Regenerate.
* opncls.c (_bfd_new_bfd): Lock and unlock.
* po/bfd.pot: Regenerate.

Make various error-related globals thread-local

This changes bfd_error et al to be thread-local.

* Makefile.in: Regenerate.
* aclocal.m4: Include ax_tls.m4.
* ax_tls.m4: New file.
* bfd.c: (bfd_error, input_error, input_bfd, _bfd_error_buf):
Now thread-local.
(bfd_asprintf): Update docs.
* config.in, configure: Regenerate.
* configure.ac: Call AX_TLS.
* po/bfd.pot: Regenerate.

Make _bfd_error_buf static

This makes _bfd_error_buf static and adds a way to clear it. I felt
that this made the subsequent patches a little cleaner.

* bfd.c (_bfd_error_buf): Now static.
(bfd_set_input_error): Use _bfd_clear_error_data.
(_bfd_clear_error_data): New function.
(bfd_init): Use _bfd_clear_error_data.
* libbfd.h: Regenerate.
* opncls.c (bfd_close_all_done): Use _bfd_clear_error_data.
* po/bfd.pot: Regenerate.

Automatic date update in version.in

aarch64: Add LSE128 instructions

Implement, together with the necessary tests, the following new LSE128
atomic instructions:

  * Atomic bit clear on quadword in memory (ldclrp{a|l|al});
  * Atomic bit set on quadword in memory (ldsetp{a|l|al});
  * Swap quadword in memory (swpp{a|l|al});

gas/ChangeLog:

* testsuite/gas/aarch64/lse128-atomic.d: New.
* testsuite/gas/aarch64/lse128-atomic.s: Likewise.

opcodes/ChangeLog:

* aarch64-tbl.h (ldclrp): new _LSE128_INSN entry.
(ldclrpa):  Likewise.
(ldclrpal): Likewise.
(ldclrpl): Likewise.
(ldsetp): Likewise.
(ldsetpa): Likewise.
(ldsetpal): Likewise.
(ldsetpl): Likewise.
(swpp): Likewise.
(swppa): Likewise.
(swppal): Likewise.
(swppl): Likewise.
* aarch64-asm-2.c: Regenerate.
* aarch64-dis-2.c: Likewise.
* aarch64-opc-2.c: Likewise.