This commit is the result of running the gdb/copyright.py script,
which automated the update of the copyright year range for all
source files managed by the GDB project to be updated to include
year 2023.

This commit brings all the changes made by running gdb/copyright.py
as per GDB's Start of New Year Procedure.

For the avoidance of doubt, all changes in this commits were
performed by the script.

This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...

gdb/ChangeLog

        Update copyright year range in copyright header of all GDB files.

Many spots incorrectly use only spaces for indentation (for example,
there are a lot of spots in ada-lang.c).  I've always found it awkward
when I needed to edit one of these spots: do I keep the original wrong
indentation, or do I fix it?  What if the lines around it are also
wrong, do I fix them too?  I probably don't want to fix them in the same
patch, to avoid adding noise to my patch.

So I propose to fix as much as possible once and for all (hopefully).

One typical counter argument for this is that it makes code archeology
more difficult, because git-blame will show this commit as the last
change for these lines.  My counter counter argument is: when
git-blaming, you often need to do "blame the file at the parent commit"
anyway, to go past some other refactor that touched the line you are
interested in, but is not the change you are looking for.  So you
already need a somewhat efficient way to do this.

Using some interactive tool, rather than plain git-blame, makes this
trivial.  For example, I use "tig blame <file>", where going back past
the commit that changed the currently selected line is one keystroke.
It looks like Magit in Emacs does it too (though I've never used it).
Web viewers of Github and Gitlab do it too.  My point is that it won't
really make archeology more difficult.

The other typical counter argument is that it will cause conflicts with
existing patches.  That's true... but it's a one time cost, and those
are not conflicts that are difficult to resolve.  I have also tried "git
rebase --ignore-whitespace", it seems to work well.  Although that will
re-introduce the faulty indentation, so one needs to take care of fixing
the indentation in the patch after that (which is easy).

gdb/ChangeLog:

	* aarch64-linux-tdep.c: Fix indentation.
	* aarch64-ravenscar-thread.c: Fix indentation.
	* aarch64-tdep.c: Fix indentation.
	* aarch64-tdep.h: Fix indentation.
	* ada-lang.c: Fix indentation.
	* ada-lang.h: Fix indentation.
	* ada-tasks.c: Fix indentation.
	* ada-typeprint.c: Fix indentation.
	* ada-valprint.c: Fix indentation.
	* ada-varobj.c: Fix indentation.
	* addrmap.c: Fix indentation.
	* addrmap.h: Fix indentation.
	* agent.c: Fix indentation.
	* aix-thread.c: Fix indentation.
	* alpha-bsd-nat.c: Fix indentation.
	* alpha-linux-tdep.c: Fix indentation.
	* alpha-mdebug-tdep.c: Fix indentation.
	* alpha-nbsd-tdep.c: Fix indentation.
	* alpha-obsd-tdep.c: Fix indentation.
	* alpha-tdep.c: Fix indentation.
	* amd64-bsd-nat.c: Fix indentation.
	* amd64-darwin-tdep.c: Fix indentation.
	* amd64-linux-nat.c: Fix indentation.
	* amd64-linux-tdep.c: Fix indentation.
	* amd64-nat.c: Fix indentation.
	* amd64-obsd-tdep.c: Fix indentation.
	* amd64-tdep.c: Fix indentation.
	* amd64-windows-tdep.c: Fix indentation.
	* annotate.c: Fix indentation.
	* arc-tdep.c: Fix indentation.
	* arch-utils.c: Fix indentation.
	* arch/arm-get-next-pcs.c: Fix indentation.
	* arch/arm.c: Fix indentation.
	* arm-linux-nat.c: Fix indentation.
	* arm-linux-tdep.c: Fix indentation.
	* arm-nbsd-tdep.c: Fix indentation.
	* arm-pikeos-tdep.c: Fix indentation.
	* arm-tdep.c: Fix indentation.
	* arm-tdep.h: Fix indentation.
	* arm-wince-tdep.c: Fix indentation.
	* auto-load.c: Fix indentation.
	* auxv.c: Fix indentation.
	* avr-tdep.c: Fix indentation.
	* ax-gdb.c: Fix indentation.
	* ax-general.c: Fix indentation.
	* bfin-linux-tdep.c: Fix indentation.
	* block.c: Fix indentation.
	* block.h: Fix indentation.
	* blockframe.c: Fix indentation.
	* bpf-tdep.c: Fix indentation.
	* break-catch-sig.c: Fix indentation.
	* break-catch-syscall.c: Fix indentation.
	* break-catch-throw.c: Fix indentation.
	* breakpoint.c: Fix indentation.
	* breakpoint.h: Fix indentation.
	* bsd-uthread.c: Fix indentation.
	* btrace.c: Fix indentation.
	* build-id.c: Fix indentation.
	* buildsym-legacy.h: Fix indentation.
	* buildsym.c: Fix indentation.
	* c-typeprint.c: Fix indentation.
	* c-valprint.c: Fix indentation.
	* c-varobj.c: Fix indentation.
	* charset.c: Fix indentation.
	* cli/cli-cmds.c: Fix indentation.
	* cli/cli-decode.c: Fix indentation.
	* cli/cli-decode.h: Fix indentation.
	* cli/cli-script.c: Fix indentation.
	* cli/cli-setshow.c: Fix indentation.
	* coff-pe-read.c: Fix indentation.
	* coffread.c: Fix indentation.
	* compile/compile-cplus-types.c: Fix indentation.
	* compile/compile-object-load.c: Fix indentation.
	* compile/compile-object-run.c: Fix indentation.
	* completer.c: Fix indentation.
	* corefile.c: Fix indentation.
	* corelow.c: Fix indentation.
	* cp-abi.h: Fix indentation.
	* cp-namespace.c: Fix indentation.
	* cp-support.c: Fix indentation.
	* cp-valprint.c: Fix indentation.
	* cris-linux-tdep.c: Fix indentation.
	* cris-tdep.c: Fix indentation.
	* darwin-nat-info.c: Fix indentation.
	* darwin-nat.c: Fix indentation.
	* darwin-nat.h: Fix indentation.
	* dbxread.c: Fix indentation.
	* dcache.c: Fix indentation.
	* disasm.c: Fix indentation.
	* dtrace-probe.c: Fix indentation.
	* dwarf2/abbrev.c: Fix indentation.
	* dwarf2/attribute.c: Fix indentation.
	* dwarf2/expr.c: Fix indentation.
	* dwarf2/frame.c: Fix indentation.
	* dwarf2/index-cache.c: Fix indentation.
	* dwarf2/index-write.c: Fix indentation.
	* dwarf2/line-header.c: Fix indentation.
	* dwarf2/loc.c: Fix indentation.
	* dwarf2/macro.c: Fix indentation.
	* dwarf2/read.c: Fix indentation.
	* dwarf2/read.h: Fix indentation.
	* elfread.c: Fix indentation.
	* eval.c: Fix indentation.
	* event-top.c: Fix indentation.
	* exec.c: Fix indentation.
	* exec.h: Fix indentation.
	* expprint.c: Fix indentation.
	* f-lang.c: Fix indentation.
	* f-typeprint.c: Fix indentation.
	* f-valprint.c: Fix indentation.
	* fbsd-nat.c: Fix indentation.
	* fbsd-tdep.c: Fix indentation.
	* findvar.c: Fix indentation.
	* fork-child.c: Fix indentation.
	* frame-unwind.c: Fix indentation.
	* frame-unwind.h: Fix indentation.
	* frame.c: Fix indentation.
	* frv-linux-tdep.c: Fix indentation.
	* frv-tdep.c: Fix indentation.
	* frv-tdep.h: Fix indentation.
	* ft32-tdep.c: Fix indentation.
	* gcore.c: Fix indentation.
	* gdb_bfd.c: Fix indentation.
	* gdbarch.sh: Fix indentation.
	* gdbarch.c: Re-generate
	* gdbarch.h: Re-generate.
	* gdbcore.h: Fix indentation.
	* gdbthread.h: Fix indentation.
	* gdbtypes.c: Fix indentation.
	* gdbtypes.h: Fix indentation.
	* glibc-tdep.c: Fix indentation.
	* gnu-nat.c: Fix indentation.
	* gnu-nat.h: Fix indentation.
	* gnu-v2-abi.c: Fix indentation.
	* gnu-v3-abi.c: Fix indentation.
	* go32-nat.c: Fix indentation.
	* guile/guile-internal.h: Fix indentation.
	* guile/scm-cmd.c: Fix indentation.
	* guile/scm-frame.c: Fix indentation.
	* guile/scm-iterator.c: Fix indentation.
	* guile/scm-math.c: Fix indentation.
	* guile/scm-ports.c: Fix indentation.
	* guile/scm-pretty-print.c: Fix indentation.
	* guile/scm-value.c: Fix indentation.
	* h8300-tdep.c: Fix indentation.
	* hppa-linux-nat.c: Fix indentation.
	* hppa-linux-tdep.c: Fix indentation.
	* hppa-nbsd-nat.c: Fix indentation.
	* hppa-nbsd-tdep.c: Fix indentation.
	* hppa-obsd-nat.c: Fix indentation.
	* hppa-tdep.c: Fix indentation.
	* hppa-tdep.h: Fix indentation.
	* i386-bsd-nat.c: Fix indentation.
	* i386-darwin-nat.c: Fix indentation.
	* i386-darwin-tdep.c: Fix indentation.
	* i386-dicos-tdep.c: Fix indentation.
	* i386-gnu-nat.c: Fix indentation.
	* i386-linux-nat.c: Fix indentation.
	* i386-linux-tdep.c: Fix indentation.
	* i386-nto-tdep.c: Fix indentation.
	* i386-obsd-tdep.c: Fix indentation.
	* i386-sol2-nat.c: Fix indentation.
	* i386-tdep.c: Fix indentation.
	* i386-tdep.h: Fix indentation.
	* i386-windows-tdep.c: Fix indentation.
	* i387-tdep.c: Fix indentation.
	* i387-tdep.h: Fix indentation.
	* ia64-libunwind-tdep.c: Fix indentation.
	* ia64-libunwind-tdep.h: Fix indentation.
	* ia64-linux-nat.c: Fix indentation.
	* ia64-linux-tdep.c: Fix indentation.
	* ia64-tdep.c: Fix indentation.
	* ia64-tdep.h: Fix indentation.
	* ia64-vms-tdep.c: Fix indentation.
	* infcall.c: Fix indentation.
	* infcmd.c: Fix indentation.
	* inferior.c: Fix indentation.
	* infrun.c: Fix indentation.
	* iq2000-tdep.c: Fix indentation.
	* language.c: Fix indentation.
	* linespec.c: Fix indentation.
	* linux-fork.c: Fix indentation.
	* linux-nat.c: Fix indentation.
	* linux-tdep.c: Fix indentation.
	* linux-thread-db.c: Fix indentation.
	* lm32-tdep.c: Fix indentation.
	* m2-lang.c: Fix indentation.
	* m2-typeprint.c: Fix indentation.
	* m2-valprint.c: Fix indentation.
	* m32c-tdep.c: Fix indentation.
	* m32r-linux-tdep.c: Fix indentation.
	* m32r-tdep.c: Fix indentation.
	* m68hc11-tdep.c: Fix indentation.
	* m68k-bsd-nat.c: Fix indentation.
	* m68k-linux-nat.c: Fix indentation.
	* m68k-linux-tdep.c: Fix indentation.
	* m68k-tdep.c: Fix indentation.
	* machoread.c: Fix indentation.
	* macrocmd.c: Fix indentation.
	* macroexp.c: Fix indentation.
	* macroscope.c: Fix indentation.
	* macrotab.c: Fix indentation.
	* macrotab.h: Fix indentation.
	* main.c: Fix indentation.
	* mdebugread.c: Fix indentation.
	* mep-tdep.c: Fix indentation.
	* mi/mi-cmd-catch.c: Fix indentation.
	* mi/mi-cmd-disas.c: Fix indentation.
	* mi/mi-cmd-env.c: Fix indentation.
	* mi/mi-cmd-stack.c: Fix indentation.
	* mi/mi-cmd-var.c: Fix indentation.
	* mi/mi-cmds.c: Fix indentation.
	* mi/mi-main.c: Fix indentation.
	* mi/mi-parse.c: Fix indentation.
	* microblaze-tdep.c: Fix indentation.
	* minidebug.c: Fix indentation.
	* minsyms.c: Fix indentation.
	* mips-linux-nat.c: Fix indentation.
	* mips-linux-tdep.c: Fix indentation.
	* mips-nbsd-tdep.c: Fix indentation.
	* mips-tdep.c: Fix indentation.
	* mn10300-linux-tdep.c: Fix indentation.
	* mn10300-tdep.c: Fix indentation.
	* moxie-tdep.c: Fix indentation.
	* msp430-tdep.c: Fix indentation.
	* namespace.h: Fix indentation.
	* nat/fork-inferior.c: Fix indentation.
	* nat/gdb_ptrace.h: Fix indentation.
	* nat/linux-namespaces.c: Fix indentation.
	* nat/linux-osdata.c: Fix indentation.
	* nat/netbsd-nat.c: Fix indentation.
	* nat/x86-dregs.c: Fix indentation.
	* nbsd-nat.c: Fix indentation.
	* nbsd-tdep.c: Fix indentation.
	* nios2-linux-tdep.c: Fix indentation.
	* nios2-tdep.c: Fix indentation.
	* nto-procfs.c: Fix indentation.
	* nto-tdep.c: Fix indentation.
	* objfiles.c: Fix indentation.
	* objfiles.h: Fix indentation.
	* opencl-lang.c: Fix indentation.
	* or1k-tdep.c: Fix indentation.
	* osabi.c: Fix indentation.
	* osabi.h: Fix indentation.
	* osdata.c: Fix indentation.
	* p-lang.c: Fix indentation.
	* p-typeprint.c: Fix indentation.
	* p-valprint.c: Fix indentation.
	* parse.c: Fix indentation.
	* ppc-linux-nat.c: Fix indentation.
	* ppc-linux-tdep.c: Fix indentation.
	* ppc-nbsd-nat.c: Fix indentation.
	* ppc-nbsd-tdep.c: Fix indentation.
	* ppc-obsd-nat.c: Fix indentation.
	* ppc-ravenscar-thread.c: Fix indentation.
	* ppc-sysv-tdep.c: Fix indentation.
	* ppc64-tdep.c: Fix indentation.
	* printcmd.c: Fix indentation.
	* proc-api.c: Fix indentation.
	* producer.c: Fix indentation.
	* producer.h: Fix indentation.
	* prologue-value.c: Fix indentation.
	* prologue-value.h: Fix indentation.
	* psymtab.c: Fix indentation.
	* python/py-arch.c: Fix indentation.
	* python/py-bpevent.c: Fix indentation.
	* python/py-event.c: Fix indentation.
	* python/py-event.h: Fix indentation.
	* python/py-finishbreakpoint.c: Fix indentation.
	* python/py-frame.c: Fix indentation.
	* python/py-framefilter.c: Fix indentation.
	* python/py-inferior.c: Fix indentation.
	* python/py-infthread.c: Fix indentation.
	* python/py-objfile.c: Fix indentation.
	* python/py-prettyprint.c: Fix indentation.
	* python/py-registers.c: Fix indentation.
	* python/py-signalevent.c: Fix indentation.
	* python/py-stopevent.c: Fix indentation.
	* python/py-stopevent.h: Fix indentation.
	* python/py-threadevent.c: Fix indentation.
	* python/py-tui.c: Fix indentation.
	* python/py-unwind.c: Fix indentation.
	* python/py-value.c: Fix indentation.
	* python/py-xmethods.c: Fix indentation.
	* python/python-internal.h: Fix indentation.
	* python/python.c: Fix indentation.
	* ravenscar-thread.c: Fix indentation.
	* record-btrace.c: Fix indentation.
	* record-full.c: Fix indentation.
	* record.c: Fix indentation.
	* reggroups.c: Fix indentation.
	* regset.h: Fix indentation.
	* remote-fileio.c: Fix indentation.
	* remote.c: Fix indentation.
	* reverse.c: Fix indentation.
	* riscv-linux-tdep.c: Fix indentation.
	* riscv-ravenscar-thread.c: Fix indentation.
	* riscv-tdep.c: Fix indentation.
	* rl78-tdep.c: Fix indentation.
	* rs6000-aix-tdep.c: Fix indentation.
	* rs6000-lynx178-tdep.c: Fix indentation.
	* rs6000-nat.c: Fix indentation.
	* rs6000-tdep.c: Fix indentation.
	* rust-lang.c: Fix indentation.
	* rx-tdep.c: Fix indentation.
	* s12z-tdep.c: Fix indentation.
	* s390-linux-tdep.c: Fix indentation.
	* score-tdep.c: Fix indentation.
	* ser-base.c: Fix indentation.
	* ser-mingw.c: Fix indentation.
	* ser-uds.c: Fix indentation.
	* ser-unix.c: Fix indentation.
	* serial.c: Fix indentation.
	* sh-linux-tdep.c: Fix indentation.
	* sh-nbsd-tdep.c: Fix indentation.
	* sh-tdep.c: Fix indentation.
	* skip.c: Fix indentation.
	* sol-thread.c: Fix indentation.
	* solib-aix.c: Fix indentation.
	* solib-darwin.c: Fix indentation.
	* solib-frv.c: Fix indentation.
	* solib-svr4.c: Fix indentation.
	* solib.c: Fix indentation.
	* source.c: Fix indentation.
	* sparc-linux-tdep.c: Fix indentation.
	* sparc-nbsd-tdep.c: Fix indentation.
	* sparc-obsd-tdep.c: Fix indentation.
	* sparc-ravenscar-thread.c: Fix indentation.
	* sparc-tdep.c: Fix indentation.
	* sparc64-linux-tdep.c: Fix indentation.
	* sparc64-nbsd-tdep.c: Fix indentation.
	* sparc64-obsd-tdep.c: Fix indentation.
	* sparc64-tdep.c: Fix indentation.
	* stabsread.c: Fix indentation.
	* stack.c: Fix indentation.
	* stap-probe.c: Fix indentation.
	* stubs/ia64vms-stub.c: Fix indentation.
	* stubs/m32r-stub.c: Fix indentation.
	* stubs/m68k-stub.c: Fix indentation.
	* stubs/sh-stub.c: Fix indentation.
	* stubs/sparc-stub.c: Fix indentation.
	* symfile-mem.c: Fix indentation.
	* symfile.c: Fix indentation.
	* symfile.h: Fix indentation.
	* symmisc.c: Fix indentation.
	* symtab.c: Fix indentation.
	* symtab.h: Fix indentation.
	* target-float.c: Fix indentation.
	* target.c: Fix indentation.
	* target.h: Fix indentation.
	* tic6x-tdep.c: Fix indentation.
	* tilegx-linux-tdep.c: Fix indentation.
	* tilegx-tdep.c: Fix indentation.
	* top.c: Fix indentation.
	* tracefile-tfile.c: Fix indentation.
	* tracepoint.c: Fix indentation.
	* tui/tui-disasm.c: Fix indentation.
	* tui/tui-io.c: Fix indentation.
	* tui/tui-regs.c: Fix indentation.
	* tui/tui-stack.c: Fix indentation.
	* tui/tui-win.c: Fix indentation.
	* tui/tui-winsource.c: Fix indentation.
	* tui/tui.c: Fix indentation.
	* typeprint.c: Fix indentation.
	* ui-out.h: Fix indentation.
	* unittests/copy_bitwise-selftests.c: Fix indentation.
	* unittests/memory-map-selftests.c: Fix indentation.
	* utils.c: Fix indentation.
	* v850-tdep.c: Fix indentation.
	* valarith.c: Fix indentation.
	* valops.c: Fix indentation.
	* valprint.c: Fix indentation.
	* valprint.h: Fix indentation.
	* value.c: Fix indentation.
	* value.h: Fix indentation.
	* varobj.c: Fix indentation.
	* vax-tdep.c: Fix indentation.
	* windows-nat.c: Fix indentation.
	* windows-tdep.c: Fix indentation.
	* xcoffread.c: Fix indentation.
	* xml-syscall.c: Fix indentation.
	* xml-tdesc.c: Fix indentation.
	* xstormy16-tdep.c: Fix indentation.
	* xtensa-config.c: Fix indentation.
	* xtensa-linux-nat.c: Fix indentation.
	* xtensa-linux-tdep.c: Fix indentation.
	* xtensa-tdep.c: Fix indentation.

gdbserver/ChangeLog:

	* ax.cc: Fix indentation.
	* dll.cc: Fix indentation.
	* inferiors.h: Fix indentation.
	* linux-low.cc: Fix indentation.
	* linux-nios2-low.cc: Fix indentation.
	* linux-ppc-ipa.cc: Fix indentation.
	* linux-ppc-low.cc: Fix indentation.
	* linux-x86-low.cc: Fix indentation.
	* linux-xtensa-low.cc: Fix indentation.
	* regcache.cc: Fix indentation.
	* server.cc: Fix indentation.
	* tracepoint.cc: Fix indentation.

gdbsupport/ChangeLog:

	* common-exceptions.h: Fix indentation.
	* event-loop.cc: Fix indentation.
	* fileio.cc: Fix indentation.
	* filestuff.cc: Fix indentation.
	* gdb-dlfcn.cc: Fix indentation.
	* gdb_string_view.h: Fix indentation.
	* job-control.cc: Fix indentation.
	* signals.cc: Fix indentation.

Change-Id: I4bad7ae6be0fbe14168b8ebafb98ffe14964a695

This commit adds multi-target support to GDB.  What this means is that
with this commit, GDB can now be connected to different targets at the
same time.  E.g., you can debug a live native process and a core dump
at the same time, connect to multiple gdbservers, etc.

Actually, the word "target" is overloaded in gdb.  We already have a
target stack, with pushes several target_ops instances on top of one
another.  We also have "info target" already, which means something
completely different to what this patch does.

So from here on, I'll be using the "target connections" term, to mean
an open process_stratum target, pushed on a target stack.  This patch
makes gdb have multiple target stacks, and multiple process_stratum
targets open simultaneously.  The user-visible changes / commands will
also use this terminology, but of course it's all open to debate.

User-interface-wise, not that much changes.  The main difference is
that each inferior may have its own target connection.

A target connection (e.g., a target extended-remote connection) may
support debugging multiple processes, just as before.

Say you're debugging against gdbserver in extended-remote mode, and
you do "add-inferior" to prepare to spawn a new process, like:

 (gdb) target extended-remote :9999
 ...
 (gdb) start
 ...
 (gdb) add-inferior
 Added inferior 2
 (gdb) inferior 2
 [Switching to inferior 2 [<null>] (<noexec>)]
 (gdb) file a.out
 ...
 (gdb) start
 ...

At this point, you have two inferiors connected to the same gdbserver.

With this commit, GDB will maintain a target stack per inferior,
instead of a global target stack.

To preserve the behavior above, by default, "add-inferior" makes the
new inferior inherit a copy of the target stack of the current
inferior.  Same across a fork - the child inherits a copy of the
target stack of the parent.  While the target stacks are copied, the
targets themselves are not.  Instead, target_ops is made a
refcounted_object, which means that target_ops instances are
refcounted, which each inferior counting for a reference.

What if you want to create an inferior and connect it to some _other_
target?  For that, this commit introduces a new "add-inferior
-no-connection" option that makes the new inferior not share the
current inferior's target.  So you could do:

 (gdb) target extended-remote :9999
 Remote debugging using :9999
 ...
 (gdb) add-inferior -no-connection
 [New inferior 2]
 Added inferior 2
 (gdb) inferior 2
 [Switching to inferior 2 [<null>] (<noexec>)]
 (gdb) info inferiors
   Num  Description       Executable
   1    process 18401     target:/home/pedro/tmp/main
 * 2    <null>
 (gdb) tar extended-remote :10000
 Remote debugging using :10000
 ...
 (gdb) info inferiors
   Num  Description       Executable
   1    process 18401     target:/home/pedro/tmp/main
 * 2    process 18450     target:/home/pedro/tmp/main
 (gdb)

A following patch will extended "info inferiors" to include a column
indicating which connection an inferior is bound to, along with a
couple other UI tweaks.

Other than that, debugging is the same as before.  Users interact with
inferiors and threads as before.  The only difference is that
inferiors may be bound to processes running in different machines.

That's pretty much all there is to it in terms of noticeable UI
changes.

On to implementation.

Since we can be connected to different systems at the same time, a
ptid_t is no longer a unique identifier.  Instead a thread can be
identified by a pair of ptid_t and 'process_stratum_target *', the
later being the instance of the process_stratum target that owns the
process/thread.  Note that process_stratum_target inherits from
target_ops, and all process_stratum targets inherit from
process_stratum_target.  In earlier patches, many places in gdb were
converted to refer to threads by thread_info pointer instead of
ptid_t, but there are still places in gdb where we start with a
pid/tid and need to find the corresponding inferior or thread_info
objects.  So you'll see in the patch many places adding a
process_stratum_target parameter to functions that used to take only a
ptid_t.

Since each inferior has its own target stack now, we can always find
the process_stratum target for an inferior.  That is done via a
inf->process_target() convenience method.

Since each inferior has its own target stack, we need to handle the
"beneath" calls when servicing target calls.  The solution I settled
with is just to make sure to switch the current inferior to the
inferior you want before making a target call.  Not relying on global
context is just not feasible in current GDB.  Fortunately, there
aren't that many places that need to do that, because generally most
code that calls target methods already has the current context
pointing to the right inferior/thread.  Note, to emphasize -- there's
no method to "switch to this target stack".  Instead, you switch the
current inferior, and that implicitly switches the target stack.

In some spots, we need to iterate over all inferiors so that we reach
all target stacks.

Native targets are still singletons.  There's always only a single
instance of such targets.

Remote targets however, we'll have one instance per remote connection.

The exec target is still a singleton.  There's only one instance.  I
did not see the point of instanciating more than one exec_target
object.

After vfork, we need to make sure to push the exec target on the new
inferior.  See exec_on_vfork.

For type safety, functions that need a {target, ptid} pair to identify
a thread, take a process_stratum_target pointer for target parameter
instead of target_ops *.  Some shared code in gdb/nat/ also need to
gain a target pointer parameter.  This poses an issue, since gdbserver
doesn't have process_stratum_target, only target_ops.  To fix this,
this commit renames gdbserver's target_ops to process_stratum_target.
I think this makes sense.  There's no concept of target stack in
gdbserver, and gdbserver's target_ops really implements a
process_stratum-like target.

The thread and inferior iterator functions also gain
process_stratum_target parameters.  These are used to be able to
iterate over threads and inferiors of a given target.  Following usual
conventions, if the target pointer is null, then we iterate over
threads and inferiors of all targets.

I tried converting "add-inferior" to the gdb::option framework, as a
preparatory patch, but that stumbled on the fact that gdb::option does
not support file options yet, for "add-inferior -exec".  I have a WIP
patchset that adds that, but it's not a trivial patch, mainly due to
need to integrate readline's filename completion, so I deferred that
to some other time.

In infrun.c/infcmd.c, the main change is that we need to poll events
out of all targets.  See do_target_wait.  Right after collecting an
event, we switch the current inferior to an inferior bound to the
target that reported the event, so that target methods can be used
while handling the event.  This makes most of the code transparent to
multi-targets.  See fetch_inferior_event.

infrun.c:stop_all_threads is interesting -- in this function we need
to stop all threads of all targets.  What the function does is send an
asynchronous stop request to all threads, and then synchronously waits
for events, with target_wait, rinse repeat, until all it finds are
stopped threads.  Now that we have multiple targets, it's not
efficient to synchronously block in target_wait waiting for events out
of one target.  Instead, we implement a mini event loop, with
interruptible_select, select'ing on one file descriptor per target.
For this to work, we need to be able to ask the target for a waitable
file descriptor.  Such file descriptors already exist, they are the
descriptors registered in the main event loop with add_file_handler,
inside the target_async implementations.  This commit adds a new
target_async_wait_fd target method that just returns the file
descriptor in question.  See wait_one / stop_all_threads in infrun.c.

The 'threads_executing' global is made a per-target variable.  Since
it is only relevant to process_stratum_target targets, this is where
it is put, instead of in target_ops.

You'll notice that remote.c includes some FIXME notes.  These refer to
the fact that the global arrays that hold data for the remote packets
supported are still globals.  For example, if we connect to two
different servers/stubs, then each might support different remote
protocol features.  They might even be different architectures, like
e.g., one ARM baremetal stub, and a x86 gdbserver, to debug a
host/controller scenario as a single program.  That isn't going to
work correctly today, because of said globals.  I'm leaving fixing
that for another pass, since it does not appear to be trivial, and I'd
rather land the base work first.  It's already useful to be able to
debug multiple instances of the same server (e.g., a distributed
cluster, where you have full control over the servers installed), so I
think as is it's already reasonable incremental progress.

Current limitations:

 - You can only resume more that one target at the same time if all
   targets support asynchronous debugging, and support non-stop mode.
   It should be possible to support mixed all-stop + non-stop
   backends, but that is left for another time.  This means that
   currently in order to do multi-target with gdbserver you need to
   issue "maint set target-non-stop on".  I would like to make that
   mode be the default, but we're not there yet.  Note that I'm
   talking about how the target backend works, only.  User-visible
   all-stop mode works just fine.

 - As explained above, connecting to different remote servers at the
   same time is likely to produce bad results if they don't support the
   exact set of RSP features.

FreeBSD updates courtesy of John Baldwin.

gdb/ChangeLog:
2020-01-10  Pedro Alves  <palves@redhat.com>
	    John Baldwin  <jhb@FreeBSD.org>

	* aarch64-linux-nat.c
	(aarch64_linux_nat_target::thread_architecture): Adjust.
	* ada-tasks.c (print_ada_task_info): Adjust find_thread_ptid call.
	(task_command_1): Likewise.
	* aix-thread.c (sync_threadlists, aix_thread_target::resume)
	(aix_thread_target::wait, aix_thread_target::fetch_registers)
	(aix_thread_target::store_registers)
	(aix_thread_target::thread_alive): Adjust.
	* amd64-fbsd-tdep.c: Include "inferior.h".
	(amd64fbsd_get_thread_local_address): Pass down target.
	* amd64-linux-nat.c (ps_get_thread_area): Use ps_prochandle
	thread's gdbarch instead of target_gdbarch.
	* break-catch-sig.c (signal_catchpoint_print_it): Adjust call to
	get_last_target_status.
	* break-catch-syscall.c (print_it_catch_syscall): Likewise.
	* breakpoint.c (breakpoints_should_be_inserted_now): Consider all
	inferiors.
	(update_inserted_breakpoint_locations): Skip if inferiors with no
	execution.
	(update_global_location_list): When handling moribund locations,
	find representative inferior for location's pspace, and use thread
	count of its process_stratum target.
	* bsd-kvm.c (bsd_kvm_target_open): Pass target down.
	* bsd-uthread.c (bsd_uthread_target::wait): Use
	as_process_stratum_target and adjust thread_change_ptid and
	add_thread calls.
	(bsd_uthread_target::update_thread_list): Use
	as_process_stratum_target and adjust find_thread_ptid,
	thread_change_ptid and add_thread calls.
	* btrace.c (maint_btrace_packet_history_cmd): Adjust
	find_thread_ptid call.
	* corelow.c (add_to_thread_list): Adjust add_thread call.
	(core_target_open): Adjust add_thread_silent and thread_count
	calls.
	(core_target::pid_to_str): Adjust find_inferior_ptid call.
	* ctf.c (ctf_target_open): Adjust add_thread_silent call.
	* event-top.c (async_disconnect): Pop targets from all inferiors.
	* exec.c (add_target_sections): Push exec target on all inferiors
	sharing the program space.
	(remove_target_sections): Remove the exec target from all
	inferiors sharing the program space.
	(exec_on_vfork): New.
	* exec.h (exec_on_vfork): Declare.
	* fbsd-nat.c (fbsd_add_threads): Add fbsd_nat_target parameter.
	Pass it down.
	(fbsd_nat_target::update_thread_list): Adjust.
	(fbsd_nat_target::resume): Adjust.
	(fbsd_handle_debug_trap): Add fbsd_nat_target parameter.  Pass it
	down.
	(fbsd_nat_target::wait, fbsd_nat_target::post_attach): Adjust.
	* fbsd-tdep.c (fbsd_corefile_thread): Adjust
	get_thread_arch_regcache call.
	* fork-child.c (gdb_startup_inferior): Pass target down to
	startup_inferior and set_executing.
	* gdbthread.h (struct process_stratum_target): Forward declare.
	(add_thread, add_thread_silent, add_thread_with_info)
	(in_thread_list): Add process_stratum_target parameter.
	(find_thread_ptid(inferior*, ptid_t)): New overload.
	(find_thread_ptid, thread_change_ptid): Add process_stratum_target
	parameter.
	(all_threads()): Delete overload.
	(all_threads, all_non_exited_threads): Add process_stratum_target
	parameter.
	(all_threads_safe): Use brace initialization.
	(thread_count): Add process_stratum_target parameter.
	(set_resumed, set_running, set_stop_requested, set_executing)
	(threads_are_executing, finish_thread_state): Add
	process_stratum_target parameter.
	(switch_to_thread): Use is_current_thread.
	* i386-fbsd-tdep.c: Include "inferior.h".
	(i386fbsd_get_thread_local_address): Pass down target.
	* i386-linux-nat.c (i386_linux_nat_target::low_resume): Adjust.
	* inf-child.c (inf_child_target::maybe_unpush_target): Remove
	have_inferiors check.
	* inf-ptrace.c (inf_ptrace_target::create_inferior)
	(inf_ptrace_target::attach): Adjust.
	* infcall.c (run_inferior_call): Adjust.
	* infcmd.c (run_command_1): Pass target to
	scoped_finish_thread_state.
	(proceed_thread_callback): Skip inferiors with no execution.
	(continue_command): Rename 'all_threads' local to avoid hiding
	'all_threads' function.  Adjust get_last_target_status call.
	(prepare_one_step): Adjust set_running call.
	(signal_command): Use user_visible_resume_target.  Compare thread
	pointers instead of inferior_ptid.
	(info_program_command): Adjust to pass down target.
	(attach_command): Mark target's 'thread_executing' flag.
	(stop_current_target_threads_ns): New, factored out from ...
	(interrupt_target_1): ... this.  Switch inferior before making
	target calls.
	* inferior-iter.h
	(struct all_inferiors_iterator, struct all_inferiors_range)
	(struct all_inferiors_safe_range)
	(struct all_non_exited_inferiors_range): Filter on
	process_stratum_target too.  Remove explicit.
	* inferior.c (inferior::inferior): Push dummy target on target
	stack.
	(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors):
	Add process_stratum_target parameter, and pass it down.
	(have_live_inferiors): Adjust.
	(switch_to_inferior_and_push_target): New.
	(add_inferior_command, clone_inferior_command): Handle
	"-no-connection" parameter.  Use
	switch_to_inferior_and_push_target.
	(_initialize_inferior): Mention "-no-connection" option in
	the help of "add-inferior" and "clone-inferior" commands.
	* inferior.h: Include "process-stratum-target.h".
	(interrupt_target_1): Use bool.
	(struct inferior) <push_target, unpush_target, target_is_pushed,
	find_target_beneath, top_target, process_target, target_at,
	m_stack>: New.
	(discard_all_inferiors): Delete.
	(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors)
	(all_inferiors, all_non_exited_inferiors): Add
	process_stratum_target parameter.
	* infrun.c: Include "gdb_select.h" and <unordered_map>.
	(target_last_proc_target): New global.
	(follow_fork_inferior): Push target on new inferior.  Pass target
	to add_thread_silent.  Call exec_on_vfork.  Handle target's
	reference count.
	(follow_fork): Adjust get_last_target_status call.  Also consider
	target.
	(follow_exec): Push target on new inferior.
	(struct execution_control_state) <target>: New field.
	(user_visible_resume_target): New.
	(do_target_resume): Call target_async.
	(resume_1): Set target's threads_executing flag.  Consider resume
	target.
	(commit_resume_all_targets): New.
	(proceed): Also consider resume target.  Skip threads of inferiors
	with no execution.  Commit resumtion in all targets.
	(start_remote): Pass current inferior to wait_for_inferior.
	(infrun_thread_stop_requested): Consider target as well.  Pass
	thread_info pointer to clear_inline_frame_state instead of ptid.
	(infrun_thread_thread_exit): Consider target as well.
	(random_pending_event_thread): New inferior parameter.  Use it.
	(do_target_wait): Rename to ...
	(do_target_wait_1): ... this.  Add inferior parameter, and pass it
	down.
	(threads_are_resumed_pending_p, do_target_wait): New.
	(prepare_for_detach): Adjust calls.
	(wait_for_inferior): New inferior parameter.  Handle it.  Use
	do_target_wait_1 instead of do_target_wait.
	(fetch_inferior_event): Adjust.  Switch to representative
	inferior.  Pass target down.
	(set_last_target_status): Add process_stratum_target parameter.
	Save target in global.
	(get_last_target_status): Add process_stratum_target parameter and
	handle it.
	(nullify_last_target_wait_ptid): Clear 'target_last_proc_target'.
	(context_switch): Check inferior_ptid == null_ptid before calling
	inferior_thread().
	(get_inferior_stop_soon): Pass down target.
	(wait_one): Rename to ...
	(poll_one_curr_target): ... this.
	(struct wait_one_event): New.
	(wait_one): New.
	(stop_all_threads): Adjust.
	(handle_no_resumed, handle_inferior_event): Adjust to consider the
	event's target.
	(switch_back_to_stepped_thread): Also consider target.
	(print_stop_event): Update.
	(normal_stop): Update.  Also consider the resume target.
	* infrun.h (wait_for_inferior): Remove declaration.
	(user_visible_resume_target): New declaration.
	(get_last_target_status, set_last_target_status): New
	process_stratum_target parameter.
	* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
	process_stratum_target parameter, and use it.
	(clear_inline_frame_state (thread_info*)): New.
	* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
	process_stratum_target parameter.
	(clear_inline_frame_state (thread_info*)): Declare.
	* linux-fork.c (delete_checkpoint_command): Pass target down to
	find_thread_ptid.
	(checkpoint_command): Adjust.
	* linux-nat.c (linux_nat_target::follow_fork): Switch to thread
	instead of just tweaking inferior_ptid.
	(linux_nat_switch_fork): Pass target down to thread_change_ptid.
	(exit_lwp): Pass target down to find_thread_ptid.
	(attach_proc_task_lwp_callback): Pass target down to
	add_thread/set_running/set_executing.
	(linux_nat_target::attach): Pass target down to
	thread_change_ptid.
	(get_detach_signal): Pass target down to find_thread_ptid.
	Consider last target status's target.
	(linux_resume_one_lwp_throw, resume_lwp)
	(linux_handle_syscall_trap, linux_handle_extended_wait, wait_lwp)
	(stop_wait_callback, save_stop_reason, linux_nat_filter_event)
	(linux_nat_wait_1, resume_stopped_resumed_lwps): Pass target down.
	(linux_nat_target::async_wait_fd): New.
	(linux_nat_stop_lwp, linux_nat_target::thread_address_space): Pass
	target down.
	* linux-nat.h (linux_nat_target::async_wait_fd): Declare.
	* linux-tdep.c (get_thread_arch_regcache): Pass target down.
	* linux-thread-db.c (struct thread_db_info::process_target): New
	field.
	(add_thread_db_info): Save target.
	(get_thread_db_info): New process_stratum_target parameter.  Also
	match target.
	(delete_thread_db_info): New process_stratum_target parameter.
	Also match target.
	(thread_from_lwp): Adjust to pass down target.
	(thread_db_notice_clone): Pass down target.
	(check_thread_db_callback): Pass down target.
	(try_thread_db_load_1): Always push the thread_db target.
	(try_thread_db_load, record_thread): Pass target down.
	(thread_db_target::detach): Pass target down.  Always unpush the
	thread_db target.
	(thread_db_target::wait, thread_db_target::mourn_inferior): Pass
	target down.  Always unpush the thread_db target.
	(find_new_threads_callback, thread_db_find_new_threads_2)
	(thread_db_target::update_thread_list): Pass target down.
	(thread_db_target::pid_to_str): Pass current inferior down.
	(thread_db_target::get_thread_local_address): Pass target down.
	(thread_db_target::resume, maintenance_check_libthread_db): Pass
	target down.
	* nto-procfs.c (nto_procfs_target::update_thread_list): Adjust.
	* procfs.c (procfs_target::procfs_init_inferior): Declare.
	(proc_set_current_signal, do_attach, procfs_target::wait): Adjust.
	(procfs_init_inferior): Rename to ...
	(procfs_target::procfs_init_inferior): ... this and adjust.
	(procfs_target::create_inferior, procfs_notice_thread)
	(procfs_do_thread_registers): Adjust.
	* ppc-fbsd-tdep.c: Include "inferior.h".
	(ppcfbsd_get_thread_local_address): Pass down target.
	* proc-service.c (ps_xfer_memory): Switch current inferior and
	program space as well.
	(get_ps_regcache): Pass target down.
	* process-stratum-target.c
	(process_stratum_target::thread_address_space)
	(process_stratum_target::thread_architecture): Pass target down.
	* process-stratum-target.h
	(process_stratum_target::threads_executing): New field.
	(as_process_stratum_target): New.
	* ravenscar-thread.c
	(ravenscar_thread_target::update_inferior_ptid): Pass target down.
	(ravenscar_thread_target::wait, ravenscar_add_thread): Pass target
	down.
	* record-btrace.c (record_btrace_target::info_record): Adjust.
	(record_btrace_target::record_method)
	(record_btrace_target::record_is_replaying)
	(record_btrace_target::fetch_registers)
	(get_thread_current_frame_id, record_btrace_target::resume)
	(record_btrace_target::wait, record_btrace_target::stop): Pass
	target down.
	* record-full.c (record_full_wait_1): Switch to event thread.
	Pass target down.
	* regcache.c (regcache::regcache)
	(get_thread_arch_aspace_regcache, get_thread_arch_regcache): Add
	process_stratum_target parameter and handle it.
	(current_thread_target): New global.
	(get_thread_regcache): Add process_stratum_target parameter and
	handle it.  Switch inferior before calling target method.
	(get_thread_regcache): Pass target down.
	(get_thread_regcache_for_ptid): Pass target down.
	(registers_changed_ptid): Add process_stratum_target parameter and
	handle it.
	(registers_changed_thread, registers_changed): Pass target down.
	(test_get_thread_arch_aspace_regcache): New.
	(current_regcache_test): Define a couple local test_target_ops
	instances and use them for testing.
	(readwrite_regcache): Pass process_stratum_target parameter.
	(cooked_read_test, cooked_write_test): Pass mock_target down.
	* regcache.h (get_thread_regcache, get_thread_arch_regcache)
	(get_thread_arch_aspace_regcache): Add process_stratum_target
	parameter.
	(regcache::target): New method.
	(regcache::regcache, regcache::get_thread_arch_aspace_regcache)
	(regcache::registers_changed_ptid): Add process_stratum_target
	parameter.
	(regcache::m_target): New field.
	(registers_changed_ptid): Add process_stratum_target parameter.
	* remote.c (remote_state::supports_vCont_probed): New field.
	(remote_target::async_wait_fd): New method.
	(remote_unpush_and_throw): Add remote_target parameter.
	(get_current_remote_target): Adjust.
	(remote_target::remote_add_inferior): Push target.
	(remote_target::remote_add_thread)
	(remote_target::remote_notice_new_inferior)
	(get_remote_thread_info): Pass target down.
	(remote_target::update_thread_list): Skip threads of inferiors
	bound to other targets.  (remote_target::close): Don't discard
	inferiors.  (remote_target::add_current_inferior_and_thread)
	(remote_target::process_initial_stop_replies)
	(remote_target::start_remote)
	(remote_target::remote_serial_quit_handler): Pass down target.
	(remote_target::remote_unpush_target): New remote_target
	parameter.  Unpush the target from all inferiors.
	(remote_target::remote_unpush_and_throw): New remote_target
	parameter.  Pass it down.
	(remote_target::open_1): Check whether the current inferior has
	execution instead of checking whether any inferior is live.  Pass
	target down.
	(remote_target::remote_detach_1): Pass down target.  Use
	remote_unpush_target.
	(extended_remote_target::attach): Pass down target.
	(remote_target::remote_vcont_probe): Set supports_vCont_probed.
	(remote_target::append_resumption): Pass down target.
	(remote_target::append_pending_thread_resumptions)
	(remote_target::remote_resume_with_hc, remote_target::resume)
	(remote_target::commit_resume): Pass down target.
	(remote_target::remote_stop_ns): Check supports_vCont_probed.
	(remote_target::interrupt_query)
	(remote_target::remove_new_fork_children)
	(remote_target::check_pending_events_prevent_wildcard_vcont)
	(remote_target::remote_parse_stop_reply)
	(remote_target::process_stop_reply): Pass down target.
	(first_remote_resumed_thread): New remote_target parameter.  Pass
	it down.
	(remote_target::wait_as): Pass down target.
	(unpush_and_perror): New remote_target parameter.  Pass it down.
	(remote_target::readchar, remote_target::remote_serial_write)
	(remote_target::getpkt_or_notif_sane_1)
	(remote_target::kill_new_fork_children, remote_target::kill): Pass
	down target.
	(remote_target::mourn_inferior): Pass down target.  Use
	remote_unpush_target.
	(remote_target::core_of_thread)
	(remote_target::remote_btrace_maybe_reopen): Pass down target.
	(remote_target::pid_to_exec_file)
	(remote_target::thread_handle_to_thread_info): Pass down target.
	(remote_target::async_wait_fd): New.
	* riscv-fbsd-tdep.c: Include "inferior.h".
	(riscv_fbsd_get_thread_local_address): Pass down target.
	* sol2-tdep.c (sol2_core_pid_to_str): Pass down target.
	* sol-thread.c (sol_thread_target::wait, ps_lgetregs, ps_lsetregs)
	(ps_lgetfpregs, ps_lsetfpregs, sol_update_thread_list_callback):
	Adjust.
	* solib-spu.c (spu_skip_standalone_loader): Pass down target.
	* solib-svr4.c (enable_break): Pass down target.
	* spu-multiarch.c (parse_spufs_run): Pass down target.
	* spu-tdep.c (spu2ppu_sniffer): Pass down target.
	* target-delegates.c: Regenerate.
	* target.c (g_target_stack): Delete.
	(current_top_target): Return the current inferior's top target.
	(target_has_execution_1): Refer to the passed-in inferior's top
	target.
	(target_supports_terminal_ours): Check whether the initial
	inferior was already created.
	(decref_target): New.
	(target_stack::push): Incref/decref the target.
	(push_target, push_target, unpush_target): Adjust.
	(target_stack::unpush): Defref target.
	(target_is_pushed): Return bool.  Adjust to refer to the current
	inferior's target stack.
	(dispose_inferior): Delete, and inline parts ...
	(target_preopen): ... here.  Only dispose of the current inferior.
	(target_detach): Hold strong target reference while detaching.
	Pass target down.
	(target_thread_name): Add assertion.
	(target_resume): Pass down target.
	(target_ops::beneath, find_target_at): Adjust to refer to the
	current inferior's target stack.
	(get_dummy_target): New.
	(target_pass_ctrlc): Pass the Ctrl-C to the first inferior that
	has a thread running.
	(initialize_targets): Rename to ...
	(_initialize_target): ... this.
	* target.h: Include "gdbsupport/refcounted-object.h".
	(struct target_ops): Inherit refcounted_object.
	(target_ops::shortname, target_ops::longname): Make const.
	(target_ops::async_wait_fd): New method.
	(decref_target): Declare.
	(struct target_ops_ref_policy): New.
	(target_ops_ref): New typedef.
	(get_dummy_target): Declare function.
	(target_is_pushed): Return bool.
	* thread-iter.c (all_matching_threads_iterator::m_inf_matches)
	(all_matching_threads_iterator::all_matching_threads_iterator):
	Handle filter target.
	* thread-iter.h (struct all_matching_threads_iterator, struct
	all_matching_threads_range, class all_non_exited_threads_range):
	Filter by target too.  Remove explicit.
	* thread.c (threads_executing): Delete.
	(inferior_thread): Pass down current inferior.
	(clear_thread_inferior_resources): Pass down thread pointer
	instead of ptid_t.
	(add_thread_silent, add_thread_with_info, add_thread): Add
	process_stratum_target parameter.  Use it for thread and inferior
	searches.
	(is_current_thread): New.
	(thread_info::deletable): Use it.
	(find_thread_ptid, thread_count, in_thread_list)
	(thread_change_ptid, set_resumed, set_running): New
	process_stratum_target parameter.  Pass it down.
	(set_executing): New process_stratum_target parameter.  Pass it
	down.  Adjust reference to 'threads_executing'.
	(threads_are_executing): New process_stratum_target parameter.
	Adjust reference to 'threads_executing'.
	(set_stop_requested, finish_thread_state): New
	process_stratum_target parameter.  Pass it down.
	(switch_to_thread): Also match inferior.
	(switch_to_thread): New process_stratum_target parameter.  Pass it
	down.
	(update_threads_executing): Reimplement.
	* top.c (quit_force): Pop targets from all inferior.
	(gdb_init): Don't call initialize_targets.
	* windows-nat.c (windows_nat_target) <get_windows_debug_event>:
	Declare.
	(windows_add_thread, windows_delete_thread): Adjust.
	(get_windows_debug_event): Rename to ...
	(windows_nat_target::get_windows_debug_event): ... this.  Adjust.
	* tracefile-tfile.c (tfile_target_open): Pass down target.
	* gdbsupport/common-gdbthread.h (struct process_stratum_target):
	Forward declare.
	(switch_to_thread): Add process_stratum_target parameter.
	* mi/mi-interp.c (mi_on_resume_1): Add process_stratum_target
	parameter.  Use it.
	(mi_on_resume): Pass target down.
	* nat/fork-inferior.c (startup_inferior): Add
	process_stratum_target parameter.  Pass it down.
	* nat/fork-inferior.h (startup_inferior): Add
	process_stratum_target parameter.
	* python/py-threadevent.c (py_get_event_thread): Pass target down.

gdb/gdbserver/ChangeLog:
2020-01-10  Pedro Alves  <palves@redhat.com>

	* fork-child.c (post_fork_inferior): Pass target down to
	startup_inferior.
	* inferiors.c (switch_to_thread): Add process_stratum_target
	parameter.
	* lynx-low.c (lynx_target_ops): Now a process_stratum_target.
	* nto-low.c (nto_target_ops): Now a process_stratum_target.
	* linux-low.c (linux_target_ops): Now a process_stratum_target.
	* remote-utils.c (prepare_resume_reply): Pass the target to
	switch_to_thread.
	* target.c (the_target): Now a process_stratum_target.
	(done_accessing_memory): Pass the target to switch_to_thread.
	(set_target_ops): Ajust to use process_stratum_target.
	* target.h (struct target_ops): Rename to ...
	(struct process_stratum_target): ... this.
	(the_target, set_target_ops): Adjust.
	(prepare_to_access_memory): Adjust comment.
	* win32-low.c (child_xfer_memory): Adjust to use
	process_stratum_target.
	(win32_target_ops): Now a process_stratum_target.

gdb/ChangeLog:

        Update copyright year range in all GDB files.

This commit applies all changes made after running the gdb/copyright.py
script.

Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.

gdb/ChangeLog:

	Update copyright year range in all GDB files.

An review by Simon of an earlier showed a few spots related to
thread_to_thread_object that could be simplified.  This also detected
a latent bug, where thread_to_thread_object was inconsistent about
setting the Python exception before a NULL return.

Tested on x86-64 Fedora 28.

gdb/ChangeLog
2018-09-16  Tom Tromey  <tom@tromey.com>

	* python/py-threadevent.c (py_get_event_thread): Simplify.
	* python/py-inferior.c (infpy_thread_from_thread_handle):
	Return immediately after calling thread_to_thread_object.  Use
	Py_RETURN_NONE.
	(thread_to_thread_object): Set the exception on a NULL return.

This changes thread_to_thread_object to return a new reference and
fixes up all the callers.

gdb/ChangeLog
2018-09-16  Tom Tromey  <tom@tromey.com>

	* python/python-internal.h (thread_to_thread_object): Change
	return type.
	* python/py-inferior.c (thread_to_thread_object): Return a new
	reference.
	(infpy_thread_from_thread_handle): Update.
	* python/py-infthread.c (gdbpy_selected_thread): Update.
	* python/py-stopevent.c (create_stop_event_object): Update.
	* python/py-threadevent.c (py_get_event_thread): Return a new
	reference.
	(py_get_event_thread): Update.
	* python/py-event.h (py_get_event_thread): Change return type.
	* python/py-continueevent.c (create_continue_event_object):
	Update.

The pythread variable could be used without being initialized, fix it by
initializing it to nullptr.

gdb/ChangeLog:

	* python/py-threadevent.c (py_get_event_thread): Initialize
	pythread.

gdb/ChangeLog:
2018-08-24  Pedro Alves  <palves@redhat.com>

	* python/py-bpevent.c (create_breakpoint_event_object): Use
	copy-initialization.
	* python/py-continueevent.c (emit_continue_event): Use
	copy-initialization.
	* python/py-exitedevent.c (create_exited_event_object): Return a
	gdbpy_ref<>.
	(emit_exited_event): Use copy-initialization.
	* python/py-inferior.c (python_new_inferior)
	(python_inferior_deleted, add_thread_object): Use
	copy-initialization.
	* python/py-infevents.c (create_inferior_call_event_object)
	(create_register_changed_event_object)
	(create_memory_changed_event_object): Return a gdbpy_ref<>.
	(emit_inferior_call_event, emit_memory_changed_event)
	(emit_register_changed_event): Use copy-initialization.
	* python/py-newobjfileevent.c (create_new_objfile_event_object):
	Return a gdbpy_ref<>.
	(emit_new_objfile_event): Use copy-initialization.
	(create_clear_objfiles_event_object): Return a gdbpy_ref<>.
	(emit_clear_objfiles_event): Use copy-initialization.
	* python/py-signalevent.c (create_signal_event_object): Use
	copy-initialization.
	* python/py-threadevent.c (create_thread_event_object): Use
	copy-initialization.

This commit fixes a 8.1->8.2 regression exposed by
gdb.python/py-evthreads.exp when testing with
--target_board=native-gdbserver.

gdb.log shows:

  src/gdb/thread.c:93: internal-error: thread_info* inferior_thread(): Assertion `tp' failed.
  A problem internal to GDB has been detected,
  further debugging may prove unreliable.
  Quit this debugging session? (y or n) FAIL: gdb.python/py-evthreads.exp: run to breakpoint 1 (GDB internal error)

A backtrace shows (frames #2 and #10 highlighted) that the assertion
fails when GDB is setting up the connection to the remote target, in
non-stop mode:

  #0  0x0000000000622ff0 in internal_error(char const*, int, char const*, ...) (file=0xc1ad98 "src/gdb/thread.c", line=93, fmt=0xc1ad20 "%s: Assertion `%s' failed.") at src/gdb/common/errors.c:54
  #1  0x000000000089567e in inferior_thread() () at src/gdb/thread.c:93
= #2  0x00000000004da91d in get_event_thread() () at src/gdb/python/py-threadevent.c:38
  #3  0x00000000004da9b7 in create_thread_event_object(_typeobject*, _object*) (py_type=0x11574c0 <continue_event_object_type>, thread=0x0)
      at src/gdb/python/py-threadevent.c:60
  #4  0x00000000004bf6fe in create_continue_event_object() () at src/gdb/python/py-continueevent.c:27
  #5  0x00000000004bf738 in emit_continue_event(ptid_t) (ptid=...) at src/gdb/python/py-continueevent.c:40
  #6  0x00000000004c7d47 in python_on_resume(ptid_t) (ptid=...) at src/gdb/python/py-inferior.c:108
  #7  0x0000000000485bfb in std::_Function_handler<void (ptid_t), void (*)(ptid_t)>::_M_invoke(std::_Any_data const&, ptid_t&&) (__functor=..., __args#0=...) at /usr/include/c++/7/bits/std_function.h:316
  #8  0x000000000089b416 in std::function<void (ptid_t)>::operator()(ptid_t) const (this=0x12aa600, __args#0=...)
      at /usr/include/c++/7/bits/std_function.h:706
  #9  0x000000000089aa0e in gdb::observers::observable<ptid_t>::notify(ptid_t) const (this=0x118a7a0 <gdb::observers::target_resumed>, args#0=...)
      at src/gdb/common/observable.h:106
= #10 0x0000000000896fbe in set_running(ptid_t, int) (ptid=..., running=1) at src/gdb/thread.c:880
  #11 0x00000000007f750f in remote_target::remote_add_thread(ptid_t, bool, bool) (this=0x12c5440, ptid=..., running=true, executing=true) at src/gdb/remote.c:2434
  #12 0x00000000007f779d in remote_target::remote_notice_new_inferior(ptid_t, int) (this=0x12c5440, currthread=..., executing=1)
      at src/gdb/remote.c:2515
  #13 0x00000000007f9c44 in remote_target::update_thread_list() (this=0x12c5440) at src/gdb/remote.c:3831
  #14 0x00000000007fb922 in remote_target::start_remote(int, int) (this=0x12c5440, from_tty=0, extended_p=0)
      at src/gdb/remote.c:4655
  #15 0x00000000007fd102 in remote_target::open_1(char const*, int, int) (name=0x1a4f45e "localhost:2346", from_tty=0, extended_p=0)
      at src/gdb/remote.c:5638
  #16 0x00000000007fbec1 in remote_target::open(char const*, int) (name=0x1a4f45e "localhost:2346", from_tty=0)
      at src/gdb/remote.c:4862

So on frame #10, we're marking a newly-discovered thread as running,
and that causes the Python API to emit a gdb.ContinueEvent.
gdb.ContinueEvent is a gdb.ThreadEvent, and as such includes the event
thread as the "inferior_thread" attribute.  The problem is that when
we get to frame #3/#4, we lost all references to the thread that is
being marked as running.  create_continue_event_object assumes that it
is the current thread, which is not true in this case.

Fix this by passing down the right thread in
create_continue_event_object.  Also remove
create_thread_event_object's default argument and have the only other
caller left pass down the right thread explicitly too.

gdb/ChangeLog:
2018-08-24  Pedro Alves  <palves@redhat.com>
	    Simon Marchi  <simon.marchi@ericsson.com>

	PR gdb/23379
	* python/py-continueevent.c: Include "gdbthread.h".
	(create_continue_event_object): Add intro comment.  Add 'ptid'
	parameter.  Use it to find thread to pass to
	create_thread_event_object.
	(emit_continue_event): Pass PTID down to
	create_continue_event_object.
	* python/py-event.h (py_get_event_thread): Declare.
	(create_thread_event_object): Remove default from 'thread'
	parameter.
	* python/py-stopevent.c (create_stop_event_object): Use
	py_get_event_thread.
	* python/py-threadevent.c (get_event_thread): Rename to ...
	(py_get_event_thread): ... this, make extern, add 'ptid' parameter
	and use it to find the thread.
	(create_thread_event_object): Assert that THREAD isn't null.
	Don't find the event thread here.

This is more preparation bits for multi-target support.

In a multi-target scenario, we need to address the case of different
processes/threads running on different targets that happen to have the
same PID/PTID.  E.g., we can have both process 123 in target 1, and
process 123 in target 2, while they're in reality different processes
running on different machines.  Or maybe we've loaded multiple
instances of the same core file.  Etc.

To address this, in my WIP multi-target branch, threads and processes
are uniquely identified by the (process_stratum target_ops *, ptid_t)
and (process_stratum target_ops *, pid) tuples respectively.  I.e.,
each process_stratum instance has its own thread/process number space.

As you can imagine, that requires passing around target_ops * pointers
in a number of functions where we're currently passing only a ptid_t
or an int.  E.g., when we look up a thread_info object by ptid_t in
find_thread_ptid, the ptid_t alone isn't sufficient.

In many cases though, we already have the thread_info or inferior
pointer handy, but we "lose" it somewhere along the call stack, only
to look it up again by ptid_t/pid.  Since thread_info or inferior
objects know their parent target, if we pass around thread_info or
inferior pointers when possible, we avoid having to add extra
target_ops parameters to many functions, and also, we eliminate a
number of by ptid_t/int lookups.

So that's what this patch does.  In a bit more detail:

- Changes a number of functions and methods to take a thread_info or
  inferior pointer instead of a ptid_t or int parameter.

- Changes a number of structure fields from ptid_t/int to inferior or
  thread_info pointers.

- Uses the inferior_thread() function whenever possible instead of
  inferior_ptid.

- Uses thread_info pointers directly when possible instead of the
  is_running/is_stopped etc. routines that require a lookup.

- A number of functions are eliminated along the way, such as:

  int valid_gdb_inferior_id (int num);
  int pid_to_gdb_inferior_id (int pid);
  int gdb_inferior_id_to_pid (int num);
  int in_inferior_list (int pid);

- A few structures and places hold a thread_info pointer across
  inferior execution, so now they take a strong reference to the
  (refcounted) thread_info object to avoid the thread_info pointer
  getting stale.  This is done in enable_thread_stack_temporaries and
  in the infcall.c code.

- Related, there's a spot in infcall.c where using a RAII object to
  handle the refcount would be handy, so a gdb::ref_ptr specialization
  for thread_info is added (thread_info_ref, in gdbthread.h), along
  with a gdb_ref_ptr policy that works for all refcounted_object types
  (in common/refcounted-object.h).

gdb/ChangeLog:
2018-06-21  Pedro Alves  <palves@redhat.com>

	* ada-lang.h (ada_get_task_number): Take a thread_info pointer
	instead of a ptid_t.  All callers adjusted.
	* ada-tasks.c (ada_get_task_number): Likewise.  All callers
	adjusted.
	(print_ada_task_info, display_current_task_id, task_command_1):
	Adjust.
	* breakpoint.c (watchpoint_in_thread_scope): Adjust to use
	inferior_thread.
	(breakpoint_kind): Adjust.
	(remove_breakpoints_pid): Rename to ...
	(remove_breakpoints_inf): ... this.  Adjust to take an inferior
	pointer.  All callers adjusted.
	(bpstat_clear_actions): Use inferior_thread.
	(get_bpstat_thread): New.
	(bpstat_do_actions): Use it.
	(bpstat_check_breakpoint_conditions, bpstat_stop_status): Adjust
	to take a thread_info pointer.  All callers adjusted.
	(set_longjmp_breakpoint_for_call_dummy, set_momentary_breakpoint)
	(breakpoint_re_set_thread): Use inferior_thread.
	* breakpoint.h (struct inferior): Forward declare.
	(bpstat_stop_status): Update.
	(remove_breakpoints_pid): Delete.
	(remove_breakpoints_inf): New.
	* bsd-uthread.c (bsd_uthread_target::wait)
	(bsd_uthread_target::update_thread_list): Use find_thread_ptid.
	* btrace.c (btrace_add_pc, btrace_enable, btrace_fetch)
	(maint_btrace_packet_history_cmd)
	(maint_btrace_clear_packet_history_cmd): Adjust.
	(maint_btrace_clear_cmd, maint_info_btrace_cmd): Adjust to use
	inferior_thread.
	* cli/cli-interp.c: Include "inferior.h".
	* common/refcounted-object.h (struct
	refcounted_object_ref_policy): New.
	* compile/compile-object-load.c: Include gdbthread.h.
	(store_regs): Use inferior_thread.
	* corelow.c (core_target::close): Use current_inferior.
	(core_target_open): Adjust to use first_thread_of_inferior and use
	the current inferior.
	* ctf.c (ctf_target::close): Adjust to use current_inferior.
	* dummy-frame.c (dummy_frame_id) <ptid>: Delete, replaced by ...
	<thread>: ... this new field.  All references adjusted.
	(dummy_frame_pop, dummy_frame_discard, register_dummy_frame_dtor):
	Take a thread_info pointer instead of a ptid_t.
	* dummy-frame.h (dummy_frame_push, dummy_frame_pop)
	(dummy_frame_discard, register_dummy_frame_dtor): Take a
	thread_info pointer instead of a ptid_t.
	* elfread.c: Include "inferior.h".
	(elf_gnu_ifunc_resolver_stop, elf_gnu_ifunc_resolver_return_stop):
	Use inferior_thread.
	* eval.c (evaluate_subexp): Likewise.
	* frame.c (frame_pop, has_stack_frames, find_frame_sal): Use
	inferior_thread.
	* gdb_proc_service.h (struct thread_info): Forward declare.
	(struct ps_prochandle) <ptid>: Delete, replaced by ...
	<thread>: ... this new field.  All references adjusted.
	* gdbarch.h, gdbarch.c: Regenerate.
	* gdbarch.sh (get_syscall_number): Replace 'ptid' parameter with a
	'thread' parameter.  All implementations and callers adjusted.
	* gdbthread.h (thread_info) <set_running>: New method.
	(delete_thread, delete_thread_silent): Take a thread_info pointer
	instead of a ptid.
	(global_thread_id_to_ptid, ptid_to_global_thread_id): Delete.
	(first_thread_of_process): Delete, replaced by ...
	(first_thread_of_inferior): ... this new function.  All callers
	adjusted.
	(any_live_thread_of_process): Delete, replaced by ...
	(any_live_thread_of_inferior): ... this new function.  All callers
	adjusted.
	(switch_to_thread, switch_to_no_thread): Declare.
	(is_executing): Delete.
	(enable_thread_stack_temporaries): Update comment.
	<enable_thread_stack_temporaries>: Take a thread_info pointer
	instead of a ptid_t.  Incref the thread.
	<~enable_thread_stack_temporaries>: Decref the thread.
	<m_ptid>: Delete
	<m_thr>: New.
	(thread_stack_temporaries_enabled_p, push_thread_stack_temporary)
	(get_last_thread_stack_temporary)
	(value_in_thread_stack_temporaries, can_access_registers_thread):
	Take a thread_info pointer instead of a ptid_t.  All callers
	adjusted.
	* infcall.c (get_call_return_value): Use inferior_thread.
	(run_inferior_call): Work with thread pointers instead of ptid_t.
	(call_function_by_hand_dummy): Work with thread pointers instead
	of ptid_t.  Use thread_info_ref.
	* infcmd.c (proceed_thread_callback): Access thread's state
	directly.
	(ensure_valid_thread, ensure_not_running): Use inferior_thread,
	access thread's state directly.
	(continue_command): Use inferior_thread.
	(info_program_command): Use find_thread_ptid and access thread
	state directly.
	(proceed_after_attach_callback): Use thread state directly.
	(notice_new_inferior): Take a thread_info pointer instead of a
	ptid_t.  All callers adjusted.
	(exit_inferior): Take an inferior pointer instead of a pid.  All
	callers adjusted.
	(exit_inferior_silent): New.
	(detach_inferior): Delete.
	(valid_gdb_inferior_id, pid_to_gdb_inferior_id)
	(gdb_inferior_id_to_pid, in_inferior_list): Delete.
	(detach_inferior_command, kill_inferior_command): Use
	find_inferior_id instead of valid_gdb_inferior_id and
	gdb_inferior_id_to_pid.
	(inferior_command): Use inferior and thread pointers.
	* inferior.h (struct thread_info): Forward declare.
	(notice_new_inferior): Take a thread_info pointer instead of a
	ptid_t.  All callers adjusted.
	(detach_inferior): Delete declaration.
	(exit_inferior, exit_inferior_silent): Take an inferior pointer
	instead of a pid.  All callers adjusted.
	(gdb_inferior_id_to_pid, pid_to_gdb_inferior_id, in_inferior_list)
	(valid_gdb_inferior_id): Delete.
	* infrun.c (follow_fork_inferior, proceed_after_vfork_done)
	(handle_vfork_child_exec_or_exit, follow_exec): Adjust.
	(struct displaced_step_inferior_state) <pid>: Delete, replaced by
	...
	<inf>: ... this new field.
	<step_ptid>: Delete, replaced by ...
	<step_thread>: ... this new field.
	(get_displaced_stepping_state): Take an inferior pointer instead
	of a pid.  All callers adjusted.
	(displaced_step_in_progress_any_inferior): Adjust.
	(displaced_step_in_progress_thread): Take a thread pointer instead
	of a ptid_t.  All callers adjusted.
	(displaced_step_in_progress, add_displaced_stepping_state): Take
	an inferior pointer instead of a pid.  All callers adjusted.
	(get_displaced_step_closure_by_addr): Adjust.
	(remove_displaced_stepping_state): Take an inferior pointer
	instead of a pid.  All callers adjusted.
	(displaced_step_prepare_throw, displaced_step_prepare)
	(displaced_step_fixup): Take a thread pointer instead of a ptid_t.
	All callers adjusted.
	(start_step_over): Adjust.
	(infrun_thread_ptid_changed): Remove bit updating ptids in the
	displaced step queue.
	(do_target_resume): Adjust.
	(fetch_inferior_event): Use inferior_thread.
	(context_switch, get_inferior_stop_soon): Take an
	execution_control_state pointer instead of a ptid_t.  All callers
	adjusted.
	(switch_to_thread_cleanup): Delete.
	(stop_all_threads): Use scoped_restore_current_thread.
	* inline-frame.c: Include "gdbthread.h".
	(inline_state) <inline_state>: Take a thread pointer instead of a
	ptid_t.  All callers adjusted.
	<ptid>: Delete, replaced by ...
	<thread>: ... this new field.
	(find_inline_frame_state): Take a thread pointer instead of a
	ptid_t.  All callers adjusted.
	(skip_inline_frames, step_into_inline_frame)
	(inline_skipped_frames, inline_skipped_symbol): Take a thread
	pointer instead of a ptid_t.  All callers adjusted.
	* inline-frame.h (skip_inline_frames, step_into_inline_frame)
	(inline_skipped_frames, inline_skipped_symbol): Likewise.
	* linux-fork.c (delete_checkpoint_command): Adjust to use thread
	pointers directly.
	* linux-nat.c (get_detach_signal): Likewise.
	* linux-thread-db.c (thread_from_lwp): New 'stopped' parameter.
	(thread_db_notice_clone): Adjust.
	(thread_db_find_new_threads_silently)
	(thread_db_find_new_threads_2, thread_db_find_new_threads_1): Take
	a thread pointer instead of a ptid_t.  All callers adjusted.
	* mi/mi-cmd-var.c: Include "inferior.h".
	(mi_cmd_var_update_iter): Update to use thread pointers.
	* mi/mi-interp.c (mi_new_thread): Update to use the thread's
	inferior directly.
	(mi_output_running_pid, mi_inferior_count): Delete, bits factored
	out to ...
	(mi_output_running): ... this new function.
	(mi_on_resume_1): Adjust to use it.
	(mi_user_selected_context_changed): Adjust to use inferior_thread.
	* mi/mi-main.c (proceed_thread): Adjust to use thread pointers
	directly.
	(interrupt_thread_callback): : Adjust to use thread and inferior
	pointers.
	* proc-service.c: Include "gdbthread.h".
	(ps_pglobal_lookup): Adjust to use the thread's inferior directly.
	* progspace-and-thread.c: Include "inferior.h".
	* progspace.c: Include "inferior.h".
	* python/py-exitedevent.c (create_exited_event_object): Adjust to
	hold a reference to an inferior_object.
	* python/py-finishbreakpoint.c (bpfinishpy_init): Adjust to use
	inferior_thread.
	* python/py-inferior.c (struct inferior_object): Give the type a
	tag name instead of a typedef.
	(python_on_normal_stop): No need to check if the current thread is
	listed.
	(inferior_to_inferior_object): Change return type to
	inferior_object.  All callers adjusted.
	(find_thread_object): Delete, bits factored out to ...
	(thread_to_thread_object): ... this new function.
	* python/py-infthread.c (create_thread_object): Use
	inferior_to_inferior_object.
	(thpy_is_stopped): Use thread pointer directly.
	(gdbpy_selected_thread): Use inferior_thread.
	* python/py-record-btrace.c (btpy_list_object) <ptid>: Delete
	field, replaced with ...
	<thread>: ... this new field.  All users adjusted.
	(btpy_insn_or_gap_new): Drop const.
	(btpy_list_new): Take a thread pointer instead of a ptid_t.  All
	callers adjusted.
	* python/py-record.c: Include "gdbthread.h".
	(recpy_insn_new, recpy_func_new): Take a thread pointer instead of
	a ptid_t.  All callers adjusted.
	(gdbpy_current_recording): Use inferior_thread.
	* python/py-record.h (recpy_record_object) <ptid>: Delete
	field, replaced with ...
	<thread>: ... this new field.  All users adjusted.
	(recpy_element_object) <ptid>: Delete
	field, replaced with ...
	<thread>: ... this new field.  All users adjusted.
	(recpy_insn_new, recpy_func_new): Take a thread pointer instead of
	a ptid_t.  All callers adjusted.
	* python/py-threadevent.c: Include "gdbthread.h".
	(get_event_thread): Use thread_to_thread_object.
	* python/python-internal.h (struct inferior_object): Forward
	declare.
	(find_thread_object, find_inferior_object): Delete declarations.
	(thread_to_thread_object, inferior_to_inferior_object): New
	declarations.
	* record-btrace.c: Include "inferior.h".
	(require_btrace_thread): Use inferior_thread.
	(record_btrace_frame_sniffer)
	(record_btrace_tailcall_frame_sniffer): Use inferior_thread.
	(get_thread_current_frame): Use scoped_restore_current_thread and
	switch_to_thread.
	(get_thread_current_frame): Use thread pointer directly.
	(record_btrace_replay_at_breakpoint): Use thread's inferior
	pointer directly.
	* record-full.c: Include "inferior.h".
	* regcache.c: Include "gdbthread.h".
	(get_thread_arch_regcache): Use the inferior's address space
	directly.
	(get_thread_regcache, registers_changed_thread): New.
	* regcache.h (get_thread_regcache(thread_info *thread)): New
	overload.
	(registers_changed_thread): New.
	(remote_target) <remote_detach_1>: Swap order of parameters.
	(remote_add_thread): <remote_add_thread>: Return the new thread.
	(get_remote_thread_info(ptid_t)): New overload.
	(remote_target::remote_notice_new_inferior): Use thread pointers
	directly.
	(remote_target::process_initial_stop_replies): Use
	thread_info::set_running.
	(remote_target::remote_detach_1, remote_target::detach)
	(extended_remote_target::detach): Adjust.
	* stack.c (frame_show_address): Use inferior_thread.
	* target-debug.h (target_debug_print_thread_info_pp): New.
	* target-delegates.c: Regenerate.
	* target.c (default_thread_address_space): Delete.
	(memory_xfer_partial_1): Use current_inferior.
	(target_detach): Use current_inferior.
	(target_thread_address_space): Delete.
	(generic_mourn_inferior): Use current_inferior.
	* target.h (struct target_ops) <thread_address_space>: Delete.
	(target_thread_address_space): Delete.
	* thread.c (init_thread_list): Use ALL_THREADS_SAFE.  Use thread
	pointers directly.
	(delete_thread_1, delete_thread, delete_thread_silent): Take a
	thread pointer instead of a ptid_t.  Adjust all callers.
	(ptid_to_global_thread_id, global_thread_id_to_ptid): Delete.
	(first_thread_of_process): Delete, replaced by ...
	(first_thread_of_inferior): ... this new function.  All callers
	adjusted.
	(any_thread_of_process): Rename to ...
	(any_thread_of_inferior): ... this, and take an inferior pointer.
	(any_live_thread_of_process): Rename to ...
	(any_live_thread_of_inferior): ... this, and take an inferior
	pointer.
	(thread_stack_temporaries_enabled_p, push_thread_stack_temporary)
	(value_in_thread_stack_temporaries)
	(get_last_thread_stack_temporary): Take a thread pointer instead
	of a ptid_t.  Adjust all callers.
	(thread_info::set_running): New.
	(validate_registers_access): Use inferior_thread.
	(can_access_registers_ptid): Rename to ...
	(can_access_registers_thread): ... this, and take a thread
	pointer.
	(print_thread_info_1): Adjust to compare thread pointers instead
	of ptids.
	(switch_to_no_thread, switch_to_thread): Make extern.
	(scoped_restore_current_thread::~scoped_restore_current_thread):
	Use m_thread pointer directly.
	(scoped_restore_current_thread::scoped_restore_current_thread):
	Use inferior_thread.
	(thread_command): Use thread pointer directly.
	(thread_num_make_value_helper): Use inferior_thread.
	* top.c (execute_command): Use inferior_thread.
	* tui/tui-interp.c: Include "inferior.h".
	* varobj.c (varobj_create): Use inferior_thread.
	(value_of_root_1): Use find_thread_global_id instead of
	global_thread_id_to_ptid.

gdb/ChangeLog:

        Update copyright year range in all GDB files

The first patch in this series went through several iterations as I'd
forgotten how many places had to be touched to add a new event and a
new event type.

This patch simplifies the process using two new ".def" files.  Now, a
new event type can be added by adding a line to "py-event-types.def",
and a new event registry can be added by adding a line to
"py-all-events.def".

ChangeLog
2017-09-11  Tom Tromey  <tom@tromey.com>

	* python/python.c (do_start_initialization): Use
	py-event-types.def to initialize types.
	Define all object type structures.
	* python/python-internal.h: Don't declare event initialization
	functions.
	* python/py-threadevent.c (thread_event_object_type): Don't
	define.
	* python/py-stopevent.c (stop_event_object_type): Don't define.
	* python/py-signalevent.c (signal_event_object_type): Don't
	declare or define.
	* python/py-newobjfileevent.c (new_objfile_event_object_type)
	(clear_objfiles_event_object_type): Don't declare or define.
	* python/py-infevents.c (inferior_call_pre_event_object_type)
	(inferior_call_post_event_object_type)
	(register_changed_event_object_type)
	(memory_changed_event_object_type): Don't declare or define.
	* python/py-inferior.c (new_thread_event_object_type)
	(new_inferior_event_object_type)
	(inferior_deleted_event_object_type): Don't declare or define.
	* python/py-exitedevent.c (exited_event_object_type): Don't
	declare or define.
	* python/py-evts.c (gdbpy_initialize_py_events): Use
	py-all-events.def.
	* python/py-events.h (thread_event_object_type): Don't declare.
	(events_object): Use py-all-events.def.
	* python/py-event.h (GDBPY_NEW_EVENT_TYPE): Remove.  Use
	py-event-types.def.
	* python/py-event-types.def: New file.
	* python/py-continueevent.c (create_continue_event_object): Don't
	declare or define.
	* python/py-bpevent.c (breakpoint_event_object_type): Don't
	declare or define.
	* python/py-all-events.def: New file.

It seems cleaner to me for functions like create_thread_event_object,
which pass object ownership to their callers, to directly return a
gdb_ref<>.  This way the ownership transfer is part of the API.  This
patch makes this change.

ChangeLog
2017-09-11  Tom Tromey  <tom@tromey.com>

	* python/py-threadevent.c (create_thread_event_object): Return
	gdbpy_ref.
	* python/py-stopevent.h (create_stop_event_object)
	(create_breakpoint_event_object, create_signal_event_object):
	Update.
	* python/py-stopevent.c (create_stop_event_object): Return
	gdbpy_ref.
	(emit_stop_event): Update.
	* python/py-signalevent.c (create_signal_event_object): Return
	gdbpy_ref.
	* python/py-infevents.c (create_inferior_call_event_object):
	Update.
	* python/py-event.h (create_event_object)
	(create_thread_event_object): Update.
	* python/py-event.c (create_event_object): Return gdbpy_ref.
	* python/py-continueevent.c: Return gdbpy_ref.
	* python/py-bpevent.c (create_breakpoint_event_object): Return
	gdbpy_ref.

This adds a few new events to gdb's Python layer: new_inferior,
inferior_deleted, and new_thread.  I wanted to be able to add a
combined inferior/thread display window to my GUI, and I needed a few
events to make this work.  This is PR python/15622.

ChangeLog
2017-09-11  Tom Tromey  <tom@tromey.com>

	PR python/15622:
	* NEWS: Add entry.
	* python/python.c (do_start_initialization): Initialize new event
	types.
	* python/python-internal.h (gdbpy_initialize_new_inferior_event)
	(gdbpy_initialize_inferior_deleted_event)
	(gdbpy_initialize_new_thread_event): Declare.
	* python/py-threadevent.c (create_thread_event_object): Add option
	"thread" parameter.
	* python/py-inferior.c (new_thread_event_object_type)
	(new_inferior_event_object_type)
	(inferior_deleted_event_object_type): Declare.
	(python_new_inferior, python_inferior_deleted): New functions.
	(add_thread_object): Emit new_thread event.
	(gdbpy_initialize_inferior): Attach new functions to corresponding
	observers.
	(new_thread, new_inferior, inferior_deleted): Define new event
	types.
	* python/py-evts.c (gdbpy_initialize_py_events): Add new
	registries.
	* python/py-events.h (events_object) <new_inferior,
	inferior_deleted, new_thread>: New fields.
	* python/py-event.h (create_thread_event_breakpoint): Add optional
	"thread" parameter.

doc/ChangeLog
2017-09-11  Tom Tromey  <tom@tromey.com>

	* python.texi (Events In Python): Document new events.

testsuite/ChangeLog
2017-09-11  Tom Tromey  <tom@tromey.com>

	* gdb.python/py-infthread.exp: Add tests for new_thread event.
	* gdb.python/py-inferior.exp: Add tests for new inferior events.

This turns gdbpy_ref into a template class, so that it can be used to
wrap subclasses of PyObject.  The default argument remains PyObject;
and this necessitated renaming uses of "gdbpy_ref" to "gdbpy_ref<>".

gdb/ChangeLog
2017-02-10  Tom Tromey  <tom@tromey.com>

	* python/py-ref.h (gdbpy_ref_policy): Now a template.
	(gdbpy_ref): Now a template; allow subclasses of PyObject to be
	used.
	* python/py-arch.c, python/py-bpevent.c, python/py-breakpoint.c,
	python/py-cmd.c, python/py-continueevent.c, python/py-event.c,
	python/py-exitedevent.c, python/py-finishbreakpoint.c,
	python/py-framefilter.c, python/py-function.c,
	python/py-inferior.c, python/py-infevents.c,
	python/py-linetable.c, python/py-newobjfileevent.c,
	python/py-param.c, python/py-prettyprint.c, python/py-ref.h,
	python/py-signalevent.c, python/py-stopevent.c,
	python/py-symbol.c, python/py-threadevent.c, python/py-type.c,
	python/py-unwind.c, python/py-utils.c, python/py-value.c,
	python/py-varobj.c, python/py-xmethods.c, python/python.c,
	varobj.c: Change gdbpy_ref to gdbpy_ref<>.

This changes the event code in the Python layer to use
gdbpy_ref, simplifying the logic in many places.

It also changes evpy_emit_event not to steal a reference to its
argument.  This is simpler to do now that gdbpy_ref is in use;
it's also a reasonable cleanup in its own right.  While doing this I
realized that evpy_emit_event should not be calling gdbpy_print_stack
(all the outermost callers do this if needed), so I removed this as
well.

2017-01-10  Tom Tromey  <tom@tromey.com>

	* python/py-threadevent.c (create_thread_event_object): Use
	gdbpy_ref.
	* python/py-stopevent.c (create_stop_event_object): Simplify.
	(emit_stop_event): Use gdbpy_ref.
	* python/py-signalevent.c (create_signal_event_object): Use
	gdbpy_ref.
	* python/py-newobjfileevent.c (create_new_objfile_event_object)
	(emit_new_objfile_event, create_clear_objfiles_event_object)
	(emit_clear_objfiles_event): Use gdbpy_ref.
	* python/py-infevents.c (create_inferior_call_event_object)
	(create_register_changed_event_object)
	(create_memory_changed_event_object, emit_inferior_call_event)
	(emit_memory_changed_event, emit_register_changed_event): Use
	gdbpy_ref.
	* python/py-exitedevent.c (create_exited_event_object)
	(emit_exited_event): Use gdbpy_ref.
	* python/py-event.h (evpy_emit_event): Remove
	CPYCHECKER_STEALS_REFERENCE_TO_ARG annotation.
	* python/py-event.c (evpy_emit_event): Use gdbpy_ref.
	* python/py-continueevent.c (emit_continue_event): Use
	gdbpy_ref.
	* python/py-breakpoint.c (gdbpy_breakpoint_created)
	(gdbpy_breakpoint_deleted, gdbpy_breakpoint_modified): Use
	gdbpy_ref.
	* python/py-bpevent.c (create_breakpoint_event_object): Use
	gdbpy_ref.

This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.

gdb/ChangeLog:

        Update copyright year range in all GDB files.

gdb/ChangeLog:

        Update year range in copyright notice of all files.

In C, we can forward declare static structure instances.  That doesn't
work in C++ though.  C++ treats these as definitions.  So then the
compiler complains about symbol redefinition, like:

 src/gdb/elfread.c:1569:29: error: redefinition of ‘const sym_fns elf_sym_fns_lazy_psyms’
 src/gdb/elfread.c:53:29: error: ‘const sym_fns elf_sym_fns_lazy_psyms’ previously declared here

The intent of static here is naturally to avoid making these objects
visible outside the compilation unit.  The equivalent in C++ would be
to instead define the objects in the anonymous namespace.  But given
that it's desirable to leave the codebase compiling as both C and C++
for a while, this just makes the objects extern.

(base_breakpoint_ops is already declared in breakpoint.h, so we can
just remove the forward declare from breakpoint.c)

gdb/ChangeLog:
2015-02-11  Tom Tromey  <tromey@redhat.com>
	    Pedro Alves <palves@redhat.com>

	* breakpoint.c (base_breakpoint_ops): Delete.
	* dwarf2loc.c (dwarf_expr_ctx_funcs): Make extern.
	* elfread.c (elf_sym_fns_gdb_index, elf_sym_fns_lazy_psyms): Make extern.
	* guile/guile.c (guile_extension_script_ops, guile_extension_ops): Make extern.
	* ppcnbsd-tdep.c (ppcnbsd2_sigtramp): Make extern.
	* python/py-arch.c (arch_object_type): Make extern.
	* python/py-block.c (block_syms_iterator_object_type): Make extern.
	* python/py-bpevent.c (breakpoint_event_object_type): Make extern.
	* python/py-cmd.c (cmdpy_object_type): Make extern.
	* python/py-continueevent.c (continue_event_object_type)
	* python/py-event.h (GDBPY_NEW_EVENT_TYPE): Remove 'qual'
	parameter.  Update all callers.
	* python/py-evtregistry.c (eventregistry_object_type): Make extern.
	* python/py-exitedevent.c (exited_event_object_type): Make extern.
	* python/py-finishbreakpoint.c (finish_breakpoint_object_type): Make extern.
	* python/py-function.c (fnpy_object_type): Make extern.
	* python/py-inferior.c (inferior_object_type, membuf_object_type): Make extern.
	* python/py-infevents.c (call_pre_event_object_type)
	(inferior_call_post_event_object_type).
	(memory_changed_event_object_type): Make extern.
	* python/py-infthread.c (thread_object_type): Make extern.
	* python/py-lazy-string.c (lazy_string_object_type): Make extern.
	* python/py-linetable.c (linetable_entry_object_type)
	(linetable_object_type, ltpy_iterator_object_type): Make extern.
	* python/py-newobjfileevent.c (new_objfile_event_object_type)
	(clear_objfiles_event_object_type): Make extern.
	* python/py-objfile.c (objfile_object_type): Make extern.
	* python/py-param.c (parmpy_object_type): Make extern.
	* python/py-progspace.c (pspace_object_type): Make extern.
	* python/py-signalevent.c (signal_event_object_type): Make extern.
	* python/py-symtab.c (symtab_object_type, sal_object_type): Make extern.
	* python/py-type.c (type_object_type, field_object_type)
	(type_iterator_object_type): Make extern.
	* python/python.c (python_extension_script_ops)
	(python_extension_ops): Make extern.
	* stap-probe.c (stap_probe_ops): Make extern.

gdb/ChangeLog:

        Update year range in copyright notice of all files.

Move infrun.c declarations out of inferior.h to a new infrun.h file.

Tested by building on:

 i686-w64-mingw32, enable-targets=all
 x86_64-linux, enable-targets=all
 i586-pc-msdosdjgpp

And also grepped the whole tree for each symbol moved to find where
infrun.h might be necessary.

gdb/
2014-05-22  Pedro Alves  <palves@redhat.com>

	* inferior.h (debug_infrun, debug_displaced, stop_on_solib_events)
	(sync_execution, sched_multi, step_stop_if_no_debug, non_stop)
	(disable_randomization, enum exec_direction_kind)
	(execution_direction, stop_registers, start_remote)
	(clear_proceed_status, proceed, resume, user_visible_resume_ptid)
	(wait_for_inferior, normal_stop, get_last_target_status)
	(prepare_for_detach, fetch_inferior_event, init_wait_for_inferior)
	(insert_step_resume_breakpoint_at_sal)
	(follow_inferior_reset_breakpoints, stepping_past_instruction_at)
	(set_step_info, print_stop_event, signal_stop_state)
	(signal_print_state, signal_pass_state, signal_stop_update)
	(signal_print_update, signal_pass_update)
	(update_signals_program_target, clear_exit_convenience_vars)
	(displaced_step_dump_bytes, update_observer_mode)
	(signal_catch_update, gdb_signal_from_command): Move
	declarations ...
	* infrun.h: ... to this new file.
	* amd64-tdep.c: Include infrun.h.
	* annotate.c: Include infrun.h.
	* arch-utils.c: Include infrun.h.
	* arm-linux-tdep.c: Include infrun.h.
	* arm-tdep.c: Include infrun.h.
	* break-catch-sig.c: Include infrun.h.
	* breakpoint.c: Include infrun.h.
	* common/agent.c: Include infrun.h instead of inferior.h.
	* corelow.c: Include infrun.h.
	* event-top.c: Include infrun.h.
	* go32-nat.c: Include infrun.h.
	* i386-tdep.c: Include infrun.h.
	* inf-loop.c: Include infrun.h.
	* infcall.c: Include infrun.h.
	* infcmd.c: Include infrun.h.
	* infrun.c: Include infrun.h.
	* linux-fork.c: Include infrun.h.
	* linux-nat.c: Include infrun.h.
	* linux-thread-db.c: Include infrun.h.
	* monitor.c: Include infrun.h.
	* nto-tdep.c: Include infrun.h.
	* procfs.c: Include infrun.h.
	* record-btrace.c: Include infrun.h.
	* record-full.c: Include infrun.h.
	* remote-m32r-sdi.c: Include infrun.h.
	* remote-mips.c: Include infrun.h.
	* remote-notif.c: Include infrun.h.
	* remote-sim.c: Include infrun.h.
	* remote.c: Include infrun.h.
	* reverse.c: Include infrun.h.
	* rs6000-tdep.c: Include infrun.h.
	* s390-linux-tdep.c: Include infrun.h.
	* solib-irix.c: Include infrun.h.
	* solib-osf.c: Include infrun.h.
	* solib-svr4.c: Include infrun.h.
	* target.c: Include infrun.h.
	* top.c: Include infrun.h.
	* windows-nat.c: Include infrun.h.
	* mi/mi-interp.c: Include infrun.h.
	* mi/mi-main.c: Include infrun.h.
	* python/py-threadevent.c: Include infrun.h.

	CPYCHECKER_RETURNS_BORROWED_REF.
	* python/python-internal.h (CPYCHECKER_RETURNS_BORROWED_REF):
	New define.
	(pspace_to_pspace_object, objfile_to_objfile_object)
	(find_thread_object): Use it.

Two modifications:
  1. The addition of 2013 to the copyright year range for every file;
  2. The use of a single year range, instead of potentially multiple
     year ranges, as approved by the FSF.

	* python/py-continueevent.c: Include defs.h.
	* python/py-event.c: Include defs.h.
	* python/py-event.h: Don't include defs.h.
	* python/py-events.h: Don't include defs.h.
	* python/py-evts.c: Include defs.h.
	* python/py-exitedevent.c: Include defs.h.
	* python/py-newobjfileevent.c: Include defs.h.
	* python/py-signalevent.c: Include defs.h.
	* python/py-stopevent.c: Include defs.h.
	* python/py-threadevent.c: Include defs.h.

	* python/py-bpevent.c (create_breakpoint_event_object): Update
	comment.
	* python/py-event.c (evpy_add_attribute): Update comment.
	* python/py-exitedevent.c (create_exited_event_object): Fix
	reference counting and error handling.
	* python/py-newobjfileevent.c (create_new_objfile_event_object):
	Fix reference counting.
	* python/py-signalevent.c (create_signal_event_object): Fix
	reference counting and error handling.
	* python/py-stopevent.c (emit_stop_event): Fix reference
	counting.
	* python/py-threadevent.c (get_event_thread): Return a
	borrowed reference.
	* python/py-type.c (convert_field): Fix reference counting.

gdb/ChangeLog:

        Copyright year update in most files of the GDB Project.