binutils_os216

Fork

Per-inferior thread list, thread ranges/iterators, down with ALL_THREADS, etc.

As preparation for multi-target, this patch makes each inferior have
its own thread list.

This isn't absolutely necessary for multi-target, but simplifies
things. It originally stemmed from the desire to eliminate the
init_thread_list calls sprinkled around, plus it makes it more
efficient to iterate over threads of a given inferior (no need to
always iterate over threads of all inferiors).

We still need to iterate over threads of all inferiors in a number of
places, which means we'd need adjust the ALL_THREADS /
ALL_NON_EXITED_THREADS macros. However, naively tweaking those macros
to have an extra for loop, like:

#define ALL_THREADS (thr, inf) \
for (inf = inferior_list; inf; inf = inf->next) \
for (thr = inf->thread_list; thr; thr = thr->next)

causes problems with code that does "break" or "continue" within the
ALL_THREADS loop body. Plus, we need to declare the extra "inf" local
variable in order to pass it as temporary variable to ALL_THREADS
(etc.)

It gets even trickier when we consider extending the macros to filter
out threads matching a ptid_t and a target. The macros become tricker
to read/write. Been there.

An alternative (which was my next attempt), is to replace the
ALL_THREADS etc. iteration style with for_each_all_threads,
for_each_non_exited_threads, etc. functions which would take a
callback as parameter, which would usually be passed a lambda.
However, I did not find that satisfactory at all, because the
resulting code ends up a little less natural / more noisy to read,
write and debug/step-through (due to use of lambdas), and in many
places where we use "continue;" to skip to the next thread now need to
use "return;". (I ran into hard to debug bugs caused by a
continue/return confusion.)

I.e., before:

ALL_NON_EXITED_THREADS (tp)
{
if (tp->not_what_I_want)
continue;
// do something
}

would turn into:

for_each_non_exited_thread ([&] (thread_info *tp)
{
if (tp->not_what_I_want)
return;
// do something
});

Lastly, the solution I settled with was to replace the ALL_THREADS /
ALL_NON_EXITED_THREADS / ALL_INFERIORS macros with (C++20-like) ranges
and iterators, such that you can instead naturaly iterate over
threads/inferiors using range-for, like e.g,.:

// all threads, including THREAD_EXITED threads.
for (thread_info *tp : all_threads ())
{ .... }

// all non-exited threads.
for (thread_info *tp : all_non_exited_threads ())
{ .... }

// all non-exited threads of INF inferior.
for (thread_info *tp : inf->non_exited_threads ())
{ .... }

The all_non_exited_threads() function takes an optional filter ptid_t as
parameter, which is quite convenient when we need to iterate over
threads matching that filter. See e.g., how the
set_executing/set_stop_requested/finish_thread_state etc. functions in
thread.c end up being simplified.

Most of the patch thus is about adding the infrustructure for allowing
the above. Later on when we get to actual multi-target, these
functions/ranges/iterators will gain a "target_ops *" parameter so
that e.g., we can iterate over all threads of a given target that
match a given filter ptid_t.

The only entry points users needs to be aware of are the
all_threads/all_non_exited_threads etc. functions seen above. Thus,
those functions are declared in gdbthread.h/inferior.h. The actual
iterators/ranges are mainly "internals" and thus are put out of view
in the new thread-iter.h/thread-iter.c/inferior-iter.h files. That
keeps the gdbthread.h/inferior.h headers quite a bit more readable.

A common/safe-iterator.h header is added which adds a template that
can be used to build "safe" iterators, which are forward iterators
that can be used to replace the ALL_THREADS_SAFE macro and other
instances of the same idiom in future.

There's a little bit of shuffling of code between
gdbthread.h/thread.c/inferior.h in the patch. That is necessary in
order to avoid circular dependencies between the
gdbthread.h/inferior.h headers.

As for the init_thread_list calls sprinkled around, they're all
eliminated by this patch, and a new, central call is added to
inferior_appeared. Note how also related to that, there's a call to
init_wait_for_inferior in remote.c that is eliminated.
init_wait_for_inferior is currently responsible for discarding skipped
inline frames, which had to be moved elsewhere. Given that nowadays
we always have a thread even for single-threaded processes, the
natural place is to delete a frame's inline frame info when we delete
the thread. I.e., from clear_thread_inferior_resources.

gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <palves@redhat.com>

* Makefile.in (COMMON_SFILES): Add thread-iter.c.
* breakpoint.c (breakpoints_should_be_inserted_now): Replace
ALL_NON_EXITED_THREADS with all_non_exited_threads.
(print_one_breakpoint_location): Replace ALL_INFERIORS with
all_inferiors.
* bsd-kvm.c: Include inferior.h.
* btrace.c (btrace_free_objfile): Replace ALL_NON_EXITED_THREADS
with all_non_exited_threads.
* common/filtered-iterator.h: New.
* common/safe-iterator.h: New.
* corelow.c (core_target_open): Don't call init_thread_list here.
* darwin-nat.c (thread_info_from_private_thread_info): Replace
ALL_THREADS with all_threads.
* fbsd-nat.c (fbsd_nat_target::resume): Replace
ALL_NON_EXITED_THREADS with inf->non_exited_threads.
* fbsd-tdep.c (fbsd_make_corefile_notes): Replace
ALL_NON_EXITED_THREADS with inf->non_exited_threads.
* fork-child.c (postfork_hook): Don't call init_thread_list here.
* gdbarch-selftests.c (register_to_value_test): Adjust.
* gdbthread.h: Don't include "inferior.h" here.
(struct inferior): Forward declare.
(enum step_over_calls_kind): Moved here from inferior.h.
(thread_info::deletable): Definition moved to thread.c.
(find_thread_ptid (inferior *, ptid_t)): Declare.
(ALL_THREADS, ALL_THREADS_BY_INFERIOR, ALL_THREADS_SAFE): Delete.
Include "thread-iter.h".
(all_threads, all_non_exited_threads, all_threads_safe): New.
(any_thread_p): Declare.
(thread_list): Delete.
* infcmd.c (signal_command): Replace ALL_NON_EXITED_THREADS with
all_non_exited_threads.
(proceed_after_attach_callback): Delete.
(proceed_after_attach): Take an inferior pointer instead of an
integer PID. Adjust to use range-for.
(attach_post_wait): Pass down inferior pointer instead of pid.
Use range-for instead of ALL_NON_EXITED_THREADS.
(detach_command): Remove init_thread_list call.
* inferior-iter.h: New.
* inferior.c (struct delete_thread_of_inferior_arg): Delete.
(delete_thread_of_inferior): Delete.
(delete_inferior, exit_inferior_1): Use range-for with
inf->threads_safe() instead of iterate_over_threads.
(inferior_appeared): Call init_thread_list here.
(discard_all_inferiors): Use all_non_exited_inferiors.
(find_inferior_id, find_inferior_pid): Use all_inferiors.
(iterate_over_inferiors): Use all_inferiors_safe.
(have_inferiors, number_of_live_inferiors): Use
all_non_exited_inferiors.
(number_of_inferiors): Use all_inferiors and std::distance.
(print_inferior): Use all_inferiors.
* inferior.h: Include gdbthread.h.
(enum step_over_calls_kind): Moved to gdbthread.h.
(struct inferior) <thread_list>: New field.
<threads, non_exited_threads, threads_safe>: New methods.
(ALL_INFERIORS): Delete.
Include "inferior-iter.h".
(ALL_NON_EXITED_INFERIORS): Delete.
(all_inferiors_safe, all_inferiors, all_non_exited_inferiors): New
functions.
* inflow.c (child_interrupt, child_pass_ctrlc): Replace
ALL_NON_EXITED_THREADS with all_non_exited_threads.
* infrun.c (follow_exec): Use all_threads_safe.
(clear_proceed_status, proceed): Use all_non_exited_threads.
(init_wait_for_inferior): Don't clear inline frame state here.
(infrun_thread_stop_requested, for_each_just_stopped_thread): Use
all_threads instead of ALL_NON_EXITED_THREADS.
(random_pending_event_thread): Use all_non_exited_threads instead
of ALL_NON_EXITED_THREADS. Use a lambda for repeated code.
(clean_up_just_stopped_threads_fsms): Use all_non_exited_threads
instead of ALL_NON_EXITED_THREADS.
(handle_no_resumed): Use all_non_exited_threads instead of
ALL_NON_EXITED_THREADS. Use all_inferiors instead of
ALL_INFERIORS.
(restart_threads, switch_back_to_stepped_thread): Use
all_non_exited_threads instead of ALL_NON_EXITED_THREADS.
* linux-nat.c (check_zombie_leaders): Replace ALL_INFERIORS with
all_inferiors.
(kill_unfollowed_fork_children): Use inf->non_exited_threads
instead of ALL_NON_EXITED_THREADS.
* linux-tdep.c (linux_make_corefile_notes): Use
inf->non_exited_threads instead of ALL_NON_EXITED_THREADS.
* linux-thread-db.c (thread_db_target::update_thread_list):
Replace ALL_INFERIORS with all_inferiors.
(thread_db_target::thread_handle_to_thread_info): Use
inf->non_exited_threads instead of ALL_NON_EXITED_THREADS.
* mi/mi-interp.c (multiple_inferiors_p): New.
(mi_on_resume_1): Simplify using all_non_exited_threads and
multiple_inferiors_p.
* mi/mi-main.c (mi_cmd_thread_list_ids): Use all_non_exited_threads
instead of ALL_NON_EXITED_THREADS.
* nto-procfs.c (nto_procfs_target::open): Don't call
init_thread_list here.
* record-btrace.c (record_btrace_target_open)
(record_btrace_target::stop_recording)
(record_btrace_target::close)
(record_btrace_target::record_is_replaying)
(record_btrace_target::resume, record_btrace_target::wait)
(record_btrace_target::record_stop_replaying): Use
all_non_exited_threads instead of ALL_NON_EXITED_THREADS.
* record-full.c (record_full_wait_1): Use all_non_exited_threads
instead of ALL_NON_EXITED_THREADS.
* regcache.c (cooked_read_test): Remove reference to global
thread_list.
* remote-sim.c (gdbsim_target::create_inferior): Don't call
init_thread_list here.
* remote.c (remote_target::update_thread_list): Use
all_threads_safe instead of ALL_NON_EXITED_THREADS.
(remote_target::process_initial_stop_replies): Replace
ALL_INFERIORS with all_non_exited_inferiors and use
all_non_exited_threads instead of ALL_NON_EXITED_THREADS.
(remote_target::open_1): Don't call init_thread_list here.
(remote_target::append_pending_thread_resumptions)
(remote_target::remote_resume_with_hc): Use all_non_exited_threads
instead of ALL_NON_EXITED_THREADS.
(remote_target::commit_resume)
(remote_target::remove_new_fork_children): Replace ALL_INFERIORS
with all_non_exited_inferiors and use all_non_exited_threads
instead of ALL_NON_EXITED_THREADS.
(remote_target::kill_new_fork_children): Use
all_non_exited_threads instead of ALL_NON_EXITED_THREADS. Remove
init_thread_list and init_wait_for_inferior calls.
(remote_target::remote_btrace_maybe_reopen)
(remote_target::thread_handle_to_thread_info): Use
all_non_exited_threads instead of ALL_NON_EXITED_THREADS.
* target.c (target_terminal::restore_inferior)
(target_terminal_is_ours_kind): Replace ALL_INFERIORS with
all_non_exited_inferiors.
* thread-iter.c: New file.
* thread-iter.h: New file.
* thread.c: Include "inline-frame.h".
(thread_list): Delete.
(clear_thread_inferior_resources): Call clear_inline_frame_state.
(init_thread_list): Use all_threads_safe instead of
ALL_THREADS_SAFE. Adjust to per-inferior thread lists.
(new_thread): Adjust to per-inferior thread lists.
(add_thread_silent): Pass inferior to find_thread_ptid.
(thread_info::deletable): New, moved from the header.
(delete_thread_1): Adjust to per-inferior thread lists.
(find_thread_global_id): Use inf->threads().
(find_thread_ptid): Use find_inferior_ptid and pass inferior to
find_thread_ptid.
(find_thread_ptid(inferior*, ptid_t)): New overload.
(iterate_over_threads): Use all_threads_safe.
(any_thread_p): New.
(thread_count): Use all_threads and std::distance.
(live_threads_count): Use all_non_exited_threads and
std::distance.
(valid_global_thread_id): Use all_threads.
(in_thread_list): Use find_thread_ptid.
(first_thread_of_inferior): Adjust to per-inferior thread lists.
(any_thread_of_inferior, any_live_thread_of_inferior): Use
inf->non_exited_threads().
(prune_threads, delete_exited_threads): Use all_threads_safe.
(thread_change_ptid): Pass inferior pointer to find_thread_ptid.
(set_resumed, set_running): Use all_non_exited_threads.
(is_thread_state, is_stopped, is_exited, is_running)
(is_executing): Delete.
(set_executing, set_stop_requested, finish_thread_state): Use
all_non_exited_threads.
(print_thread_info_1): Use all_inferiors and all_threads.
(thread_apply_all_command): Use all_non_exited_threads.
(thread_find_command): Use all_threads.
(update_threads_executing): Use all_non_exited_threads.
* tid-parse.c (parse_thread_id): Use inf->threads.
* x86-bsd-nat.c (x86bsd_dr_set): Use inf->non_exited_threads ().

Fix follow_exec latent problem

A following commit to make each inferior have its own thread list
exposes a problem with bf93d7ba99 ("Add thread after updating gdbarch
when exec'ing"), which is that we can't defer adding the thread
because that breaks try_open_exec_file which deep inside ends up
calling inferior_thread():

#5 0x0000000000637c78 in internal_error(char const*, int, char const*, ...) (file=0xc151f8 "src/gdb/thread.c", line=165, fmt=0xc15180 "%s: Assertion `%s' failed.") at src/gdb/common/errors.c:55
#6 0x00000000008a3d80 in inferior_thread() () at src/gdb/thread.c:165
#7 0x0000000000456f91 in try_thread_db_load_1(thread_db_info*) (info=0x277eb00) at src/gdb/linux-thread-db.c:830
#8 0x0000000000457554 in try_thread_db_load(char const*, int) (library=0xb01a4f "libthread_db.so.1", check_auto_load_safe=0)
at src/gdb/linux-thread-db.c:1002
#9 0x0000000000457861 in try_thread_db_load_from_sdir() () at src/gdb/linux-thread-db.c:1079
#10 0x0000000000457b72 in thread_db_load_search() () at src/gdb/linux-thread-db.c:1134
#11 0x0000000000457d29 in thread_db_load() () at src/gdb/linux-thread-db.c:1192
#12 0x0000000000457e51 in check_for_thread_db() () at src/gdb/linux-thread-db.c:1244
#13 0x0000000000457ed2 in thread_db_new_objfile(objfile*) (objfile=0x270ff60) at src/gdb/linux-thread-db.c:1273
#14 0x000000000045a92e in std::_Function_handler<void (objfile*), void (*)(objfile*)>::_M_invoke(std::_Any_data const&, objfile*&&) (__functor=..., __args#0=@0x7ffef3efe140: 0x270ff60) at /usr/include/c++/7/bits/std_function.h:316
#15 0x00000000007bbebf in std::function<void (objfile*)>::operator()(objfile*) const (this=0x24e1d18, __args#0=0x270ff60)
at /usr/include/c++/7/bits/std_function.h:706
#16 0x00000000007bba86 in gdb::observers::observable<objfile*>::notify(objfile*) const (this=0x117ce80 <gdb::observers::new_objfile>, args#0=0x270ff60) at src/gdb/common/observable.h:106
#17 0x0000000000856000 in symbol_file_add_with_addrs(bfd*, char const*, symfile_add_flags, section_addr_info*, objfile_flags, objfile*) (abfd=0x1d7dae0, name=0x254bfc0 "/ho

The problem is latent currently because inferior_thread() at that
point manages to return a thread, even though it's the wrong one (of
the old inferior).

The problem originally fixed by bf93d7ba99 was:

(...) we should avoid doing register reads
after a process does an exec and before we've updated that inferior's
gdbarch. Otherwise, we may interpret the registers using the wrong
architecture.

(...) The call to "add_thread" done just after adding the inferior is
problematic, because it ends up reading the registers (because the ptid
is re-used, we end up doing a switch_to_thread to it, which tries to
update stop_pc). (...)

The register-reading issue is no longer a problem nowadays, ever since
switch_to_thread stopped reading the stop_pc in git commit
f2ffa92bbce9 ("gdb: Eliminate the 'stop_pc' global").

So this commit basically reverts bf93d7ba99.

gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <palves@redhat.com>

* infrun.c (follow_exec) <set follow-exec new>: Add thread and
switch to it before calling into try_open_exec_file.

Avoid find_thread_ptid with null_ptid

With a following patch, find_thread_ptid will first find the inferior
for the passed-in ptid, using find_inferior_pid, and then look for the
thread in that inferior's thread list. If we pass down null_ptid to
find_thread_ptid then that means we'll end up passing 0 to
find_inferior_pid, which hits this assertion:

> struct inferior *
> find_inferior_pid (int pid)
> {
> struct inferior *inf;
>
> /* Looking for inferior pid == 0 is always wrong, and indicative of
> a bug somewhere else. There may be more than one with pid == 0,
> for instance. */
> gdb_assert (pid != 0);

This patch prepares for the change, by avoiding passing down null_ptid
to find_thread_ptid or to functions that naturally use it, such as the
target_pid_to_str call in inferior.c:add_inferior. In that latter
case, the patch changes GDB output,

from:
(gdb) add-inferior
[New inferior 2 (process 0)]

to:
(gdb) add-inferior
[New inferior 2]

which seems like a good change to me. It might not even make sense to
talk about "process" for the current target, for example.

The python_on_normal_stop change ends up avoiding looking up the
same thread twice (inferior_thread also does a look up).

gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <palves@redhat.com>

* cli/cli-interp.c (cli_on_user_selected_context_changed): Use
inferior_thread instead of find_thread_ptid, and only when
inferior_ptid is not null_ptid.
* inferior.c (add_inferior): Don't include target_pid_to_str
output when the inferior is not started.
* python/py-inferior.c (python_on_normal_stop): Don't use
find_thread_ptid.
(tui_on_user_selected_context_changed): Use inferior_thread
instead of find_thread_ptid, and only when inferior_ptid is not
null_ptid.

Remove ancient workaround

This commit removes a workaround for a bug in glibc 2.1.3, which
was released 2000-02-24 and superseded 2000-11-09.

gdb/ChangeLog:

* gdb_proc_service.h (gdb_prfpregset_t): Remove typedef.
* proc-service.c (ps_lgetfpregs, ps_lsetfpregs): Use
prfpregset_t instead of gdb_prfpregset_t.
* configure.ac (PRFPREGSET_T_BROKEN): Remove check.
* configure, config.in: Rebuild.

Move duplicated code to common/gdb_proc_service.h

This commit moves now-identical code from gdb/gdb_proc_service.h
and gdb/gdbserver/gdb_proc_service.h into the new shared file
gdb/common/gdb_proc_service.h.

gdb/ChangeLog:

* common/gdb_proc_service.h: New file, factored out from...
* gdb_proc_service.h: Moved common code to the above file.
* Makefile.in (HFILES_NO_SRCDIR): Add the above new file.

gdb/gdbserver/ChangeLog:

* gdb_proc_service.h: Moved common code to
common/gdb_proc_service.h.

Update GDB gdb_proc_service.h workaround to match gdbserver

This commit updates GDB's gdb_proc_service.h to use elf_{g,fp}regset_t
instead of gdb_{g,fp}regset_t if pr{g,fp}regset_t are undefined.
The types have been equivalent on GNU/Linux since at least 2005.

gdb/ChangeLog:

* gdb_proc_service.h: Use elf_gregset_t if prgregset_t is
undefined. Use elf_fpregset_t if prfpregset_t is undefined.

Add workaround from gdbserver's gdb_proc_service.h to GDB

This commit adds a workaround from gdbserver's gdb_proc_service.h
to GDB's. It doesn't seem to have been needed on any glibc as far
back as 2001, but it's possibly required for other C libraries so
I've retained it.

gdb/ChangeLog:

* configure.ac: Check if sys/procfs.h defines elf_fpregset_t.
(AC_CHECK_HEADERS): Check for linux/elf.h.
* configure, config.in: Rebuild.
* gdb_proc_service.h: Include linux/elf.h if sys/procfs.h
doesn't define elf_fpregset_t.

gdb_proc_service.h comment and whitespace synchronization

This commit updates comments and whitespace in GDB's and gdbserver's
gdb_proc_service.h.

gdb/ChangeLog:

* gdb_proc_service.h: Whitespace change.

gdb/gdbserver/ChangeLog:

* gdb_proc_service.h: Synchronize comments and whitespace with
GDB's version of this file.

Don't check HAVE_UNISTD_H

I noticed some spots that were checking HAVE_UNISTD_H. There is no
need to do this, as <unistd.h> is unconditionally included in many
places in gdb. This sort of cleanup was done once before, in 2013:

2013-07-01 Pedro Alves <palves@redhat.com>

* defs.h: Don't check HAVE_UNISTD_H before including <unistd.h>.
(STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO): Delete.
* tracepoint.c: Don't check HAVE_UNISTD_H before including
<unistd.h>.

HAVE_UNISTD_H seems to come from gnulib, so there are still mentions
of it in the source.

gdb/ChangeLog
2018-10-01 Tom Tromey <tom@tromey.com>

* unittests/scoped_mmap-selftests.c: Don't check HAVE_UNISTD_H.
* unittests/scoped_fd-selftests.c: Don't check HAVE_UNISTD_H.
* common/scoped_fd.h: Don't check HAVE_UNISTD_H.

Copy configure option documentation to gdb.texinfo

I realized that while I'd updated the README, I didn't update
gdb.texinfo to document the options to configure.

This patch copies the text from README into gdb.texinfo, adding
Texinfo markup.

gdb/ChangeLog
2018-10-01 Tom Tromey <tom@tromey.com>

* README: Minor change.

gdb/doc/ChangeLog
2018-10-01 Tom Tromey <tom@tromey.com>

* gdb.texinfo (Configure Options): Document configure options.

testsuite: fix is_amd64_regs_target

Commit

c221b2f Testsuite: Add gdb_can_simple_compile

changed the source file name extension of the test program from .s to .c
resulting in compile fails. This, in turn, causes is_amd64_regs_target
checks to fail. In gdb.btrace/tailcall.exp and others, this causes the
wrong source file to be picked and the test to fail on 64-bit targets.

Change the test source from an assembly program to a C program using
inline assembly.

testsuite/
* lib/gdb.exp (is_amd64_regs_target): Change assembly to C inline
assembly.

Automatic date update in version.in

Darwin: Remove unused variables [-Werror=unused-variable]

Building GDB with --host=x86_64-apple-darwin15 using G++ 5.3.0 runs
into a number of -Werror=unused-variable warnings/errors:

../../src/gdb/i386-darwin-nat.c: In function 'void i386_darwin_dr_set(int, CORE_ADDR)':
../../src/gdb/i386-darwin-nat.c:283:7: error: unused variable 'current_pid' [-Werror=unused-variable]
int current_pid;
^
[etc, etc.]

This commit fixes all such warnings.

gdb/ChangeLog:
2018-09-30 Pedro Alves <palves@redhat.com>

* darwin-nat-info.c (darwin_debug_regions_recurse)
(info_mach_exceptions_command): Remove unused local variables.
* darwin-nat.c (darwin_decode_notify_message)
(darwin_nat_target::resume, darwin_nat_target::mourn_inferior)
(darwin_stop_inferior, darwin_setup_exceptions)
(darwin_nat_target::kill, darwin_attach_pid, darwin_ptrace_him)
(darwin_nat_target::attach, darwin_nat_target::detach)
(darwin_read_write_inferior, darwin_read_dyld_info): Remove unused
local variables.
* i386-darwin-nat.c (i386_darwin_dr_set): Remove unused local
variables.

Automatic date update in version.in

Remove some leftover text in gdb/README

I accidentally left some stray text in gdb/README.
This removes it. I'm checking this in as obvious.

gdb/ChangeLog
2018-09-29 Tom Tromey <tom@tromey.com>

* README: Remove some leftover text.

Update gdb's configure instructions

gdb's README and configure instructions in the manual are quite out of
date. They mention options that haven't existed for many years, among
other things.

This patch attempts to modernize the instructions somewhat. It is not
exhaustive, just an improvement -- more could be done. Perhaps even a
couple of the nodes should simply be removed and replaced by
references to the Autoconf manual.

The README file seems to have been generated from the Texinfo at some
point in the past. I did not continue this, but instead edited it
separately.

gdb/ChangeLog
2018-09-29 Tom Tromey <tom@tromey.com>

* PROBLEMS: Rewrite.
* README: Update.

gdb/doc/ChangeLog
2018-09-29 Tom Tromey <tom@tromey.com>

* gdb.texinfo (Requirements): Mention C++, GNU make.
(Requirements): Sort the table. Add more libraries.
(Running Configure): Remove obsolete text.
(Separate Objdir): Likewise.
(Configure Options): Likewise.

Automatic date update in version.in

bfd: Use elfclass instead of bed->s->elfclass

elfclass has been set to bed->s->elfclass earlier.

* elf-properties.c (_bfd_elf_link_setup_gnu_properties): Use
elfclass instead of bed->s->elfclass.

Use the existing instruction to determine the RISC-V breakpoint kind.

RISC-V supports instructions of varying lengths. Standard existing
instructions in the base ISA are 4 bytes in length, but the 'C'
extension adds support for compressed, 2 byte instructions. RISC-V
supports two different breakpoint instructions: EBREAK is a 4 byte
instruction in the base ISA, and C.EBREAK is a 2 byte instruction only
available on processors implementing the 'C' extension. Using EBREAK
to set breakpoints on compressed instructions causes problems as the
second half of EBREAK will overwrite the first 2 bytes of the
following instruction breaking other threads in the process if their
PC is the following instruction. Thus, breakpoints on compressed
instructions need to use C.EBREAK instead of EBREAK.

Previously, the riscv architecture checked the MISA register to
determine if the 'C' extension was available. If so, it used C.EBREAK
for all breakpoints. However, the MISA register is not necessarily
available to supervisor mode operating systems. While native targets
could provide a fake MISA register value, this patch instead examines
the existing instruction at a breakpoint target to determine which
breakpoint instruction to use. If the existing instruction is a
compressed instruction, C.EBREAK is used, otherwise EBREAK is used.

gdb/ChangeLog:

* disasm-selftests.c (print_one_insn_test): Add bfd_arch_riscv to
case with explicit breakpoint kind.
* riscv-tdep.c (show_use_compressed_breakpoints): Remove
'additional_info' and related logic.
(riscv_debug_breakpoints): New variable.
(riscv_breakpoint_kind_from_pc): Use the length of the existing
instruction to determine the breakpoint kind.
(_initialize_riscv_tdep): Add 'set/show debug riscv breakpoints'
flag. Update description of 'set/show riscv
use-compressed-breakpoints' flag.

Change "xor" name in cpu_core to allow building with iso646.h or C++ compiler

This code was introduced back in 1998, and C99 appeared next year,
defining the `xor` as an 'alternative keyword' if iso646.h is
included. Moreover, C++98 defines it on the language level. As a
result, the code is not buildable with C++ compiler or if iso646.h is
included beforehand.
According to comment, `sim_cpu_core` is mostly a clone of `sim_core`,
so I renamed it to `byte_xor` as it's called in `sim_core`.

sim/common/ChangeLog:

* sim-core.h (sim_cpu_core): Rename cpu_core.xor to
cpu_core.byte_xor.
* sim-core.c (sim_core_set_xor): Likewise.
(sim_core_xor_read_buffer): Likewise.
(sim_core_xor_write_buffer): Likewise.

gdb: Change how frames are selected for 'frame' and 'info frame'.

The 'frame' command, and thanks to code reuse the 'info frame' and
'select-frame' commands, currently have an overloaded mechanism for
selecting a frame.

These commands take one or two parameters, if it's one parameter then
we first try to use the parameter as an integer to select a frame by
level (or depth in the stack). If that fails then we treat the
parameter as an address and try to select a stack frame by
stack-address. If we still have not selected a stack frame, or we
initially had two parameters, then GDB allows the user to view a stack
frame that is not part of the current backtrace. Internally, a new
frame is created with the given stack and pc addresses, and this is
shown to the user.

The result of this is that a typo by the user, entering the wrong stack
frame level for example, can result in a brand new frame being viewed
rather than an error.

The purpose of this commit is to remove this overloading, while still
offering the same functionality through some new sub-commands. By
making the default behaviour of 'frame' (and friends) be to select a
stack frame by level index, it is hoped that enough
backwards-compatibility is maintained that users will not be overly
inconvenienced.

The 'frame', 'select-frame', and 'info frame' commands now all take a
frame specification string as an argument, this string can be any of the
following:

(1) An integer. This is treated as a frame level. If a frame for
that level does not exist then the user gets an error.

(2) A string like 'level <LEVEL>', where <LEVEL> is a frame level
as in option (1) above.

(3) A string like 'address <STACK-ADDRESS>', where <STACK-ADDRESS>
is a stack-frame address. If there is no frame for this address
then the user gets an error.

(4) A string like 'function <NAME>', where <NAME> is a function name,
the inner most frame for function <NAME> is selected. If there is no
frame for function <NAME> then the user gets an error.

(5) A string like 'view <STACK-ADDRESS>', this views a new frame
with stack address <STACK-ADDRESS>.

(6) A string like 'view <STACK-ADDRESS> <PC-ADDRESS>', this views
a new frame with stack address <STACK-ADDRESS> and the pc <PC-ADDRESS>.

This change assumes that the most common use of the commands like
'frame' is to select a frame by frame level, it is for this reason
that this is the behaviour that is kept for backwards compatibility.
Any of the alternative behaviours, which are assumed to be less used,
now require a change in user behaviour.

The MI command '-stack-select-frame' has not been changed. This
ensures that we maintain backwards compatibility for existing
frontends.

gdb/ChangeLog:

(NEWS): Mention changes to frame related commands.
* cli/cli-decode.c (add_cmd_suppress_notification): New function.
(add_prefix_cmd_suppress_notification): New function.
(add_com_suppress_notification): Call
add_cmd_suppress_notification.
* command.h (add_cmd_suppress_notification): Declare.
(add_prefix_cmd_suppress_notification): Declare.
* mi/mi-cmd-stack.c: Add 'safe-ctype.h' include.
(parse_frame_specification): Moved from stack.c, with
simplification to handle a single argument.
(mi_cmd_stack_select_frame): Use parse_frame_specification, the
switch to the selected frame. Add a header comment.
* stack.c: Remove 'safe-ctype.h' include.
(find_frame_for_function): Add declaration.
(find_frame_for_address): New function.
(parse_frame_specification): Moved into mi/mi-cmd-stack.c.
(frame_selection_by_function_completer): New function.
(info_frame_command): Rename to...
(info_frame_command_core): ...this, and update parameter types.
(select_frame_command): Rename to...
(select_frame_command_core): ...this, and update parameter types.
(frame_command): Rename to...
(frame_command_core): ...this, and update parameter types.
(class frame_command_helper): New class to wrap implementations of
frame related sub-commands.
(frame_apply_cmd_list): New static global.
(frame_cmd_list): Make static.
(select_frame_cmd_list): New global for sub-commands.
(info_frame_cmd_list): New global for sub-commands.
(_initialize_stack): Register sub-commands for 'frame',
'select-frame', and 'info frame'. Update 'frame apply' commands
to use frame_apply_cmd_list. Move function local static
frame_apply_list to file static frame_apply_cmd_list for
consistency.
* stack.h (select_frame_command): Delete declarationn.
(select_frame_for_mi): Declare new function.

gdb/doc/ChangeLog:

* gdb.texinfo (Frames): Rewrite the description of 'frame number'
to highlight that the number is also the frame's level.
(Selection): Rewrite documentation for 'frame' and 'select-frame'
commands.
(Frame Info): Rewrite documentation for 'info frame' command.

gdb/testsuite/ChangeLog:

* gdb.base/frame-selection.exp: New file.
* gdb.base/frame-selection.c: New file.

RISC-V: Pc-rel to gp-rel relaxation function cleanup.

bfd/
* elfnn-riscv.c (riscv_init_pcgp_relocs): Add explanatory comment.
(riscv_free_pcgp_relocs, riscv_record_pcgp_reloc): Likewise.
(riscv_find_pcgp_hi_reloc, riscv_reocrd_pcgp_lo_reloc): Likewise.
(riscv_find_pcgp_lo_reloc): Likewise.
(riscv_delete_pcgp_hi_reloc, riscv_use_pcgp_hi_reloc): Delete.
(riscv_delete_pcgp_lo_reloc): Likewise.
(_bfd_riscv_relax_pc): Don't call riscv_use_pcgp_hi_reloc. Replace
calls to riscv_delete_pcgp_lo_reloc and riscv_delete_pcgp_hi_reloc
with TRUE. Mark abfd arg as ATTRIBUTE_UNUSED.

Automatic date update in version.in

testsuite: Fix race condition in check-libthread-db

It is possible for the created thread to reach the breakpoint before
the main thread has set errno to 23.

Prevent this using a pthread barrier.

* gdb.threads/check-libthread-db.c (thread_routine): Use a
pthread barrier.
(main): Likewise.

Automatic date update in version.in

Skip broken assembler test on Windows host.

2018-09-26 Sandra Loosemore <sandra@codesourcery.com>

gas/
* testsuite/gas/all/gas.exp: Skip "Output file must be distinct
from input" test on Windows host.

gdb/riscv: Improve non-dwarf stack unwinding

This commit improves the prologue scanning stack unwinder, to better
support AUIPC, LUI, and more variants of ADD and ADDI.

This allows unwinding over frames containing large local variables,
where the frame size does not fit into a single instruction immediate,
and is first loaded into a temporary register, before being added to
the stack pointer.

A new test is added that tests this behaviour. As there's nothing
truely RiscV specific about this test I've added it into gdb.base, but
as this depends on target specific code to perform the unwind it is
possible that some targets might fail this new test.

gdb/ChangeLog:

* riscv-tdep.c (riscv_insn::decode): Decode c.lui.
(riscv_scan_prologue): Split handling of AUIPC, LUI, ADD, ADDI,
and NOP.

gdb/testsuite/ChangeLog:

* gdb.base/large-frame-1.c: New file.
* gdb.base/large-frame-2.c: New file.
* gdb.base/large-frame.exp: New file.
* gdb.base/large-frame.h: New file.

elf32-nds32: Remove elf32_nds32_allocate_dynrelocs

It is unused, removing it fixes this error when building with clang:

/home/emaisin/src/binutils-gdb/bfd/elf32-nds32.c:3172:1: error: unused function 'elf32_nds32_allocate_dynrelocs' [-Werror,-Wunused-function]
elf32_nds32_allocate_dynrelocs (struct bfd_link_info *info, asection *sreloc,
^
1 error generated.

gcc only reports the error if you remove "inline". I don't know if this
is actually a mistake and it should actually be used though.

gdb/ChangeLog:

* elf32-nds32.c (elf32_nds32_allocate_dynrelocs): Remove.

Remove dead definition from valops.c

This removes a variable definition in valops.c that has been
surrounded by "#if 0" since gdb moved to sourceware.

gdb/ChangeLog
2018-09-26 Tom Tromey <tom@tromey.com>

* valops.c (auto_abandon): Remove dead code.

Small fix for "winheight" usage

I noticed that the usage string for "winheight" has a couple of
extraneous ">"s in it. I must have forgotten to remove these back
when I changed the text to use the GNU style for metasyntactic
variables.

gdb/ChangeLog
2018-09-26 Tom Tromey <tom@tromey.com>

* tui/tui-win.c (WIN_HEIGHT_USAGE): Remove extra ">"s.