Associate dummy_frame with ptid

Associate dummy_frame with ptid

This patch is to add ptid into dummy_frame and extend frame_id to
dummy_frame_id (which has a ptid field).  With this change, GDB uses
dummy_frame_id (thread ptid and frame_id) to find the dummy frames.

Currently, dummy frames are looked up by frame_id, which isn't
accurate in non-stop or multi-process mode.  The test case
gdb.multi/dummy-frame-restore.exp shows the problem and this patch can
fix it.

Test dummy-frame-restore.exp makes two inferiors stop at
different functions, say, inferior 1 stops at f1 while inferior 2
stops at f2.  Set a breakpoint to a function, do the inferior call
in two inferiors, and GDB has two dummy frames of the same frame_id.
When the inferior call is finished, GDB will look up a dummy frame
from its stack/list and restore the inferior's regcache.  Two
inferiors are finished in different orders, the inferiors' states are
restored differently, which is wrong.  Running dummy-frame-restore.exp
under un-patched GDB, we'll get two fails:

FAIL: gdb.multi/dummy-frame-restore.exp: inf 2 first: after infcall: bt in inferior 2
FAIL: gdb.multi/dummy-frame-restore.exp: inf 2 first: after infcall: bt in inferior 1

With this patch applied, GDB will choose the correct dummy_frame to
restore for a given inferior, because ptid is considered when looking up
dummy frames.  Two fails above are fixed.

Regression tested on x86_64-linux, both native and gdbserver.

gdb:

2014-06-27  Yao Qi  <yao@codesourcery.com>

	* breakpoint.c (check_longjmp_breakpoint_for_call_dummy):
	Change parameter type to 'struct thread_info *'.  Caller
	updated.
	* breakpoint.h (check_longjmp_breakpoint_for_call_dummy):
	Update declaration.
	* dummy-frame.c (struct dummy_frame_id): New.
	(dummy_frame_id_eq): New function.
	(struct dummy_frame) <id>: Change its type to 'struct
	dummy_frame_id'.
	(dummy_frame_push): Add parameter ptid and save it in
	dummy_frame_id.
	(pop_dummy_frame_bpt): Use ptid of dummy_frame instead of
	inferior_ptid.
	(pop_dummy_frame): Assert that the ptid of dummy_frame equals
	to inferior_ptid.
	(lookup_dummy_frame): Change parameter type to 'struct
	dummy_frame_id *'.  Callers updated.  Call dummy_frame_id_eq
	instead of frame_id_eq.
	(dummy_frame_pop): Add parameter ptid.  Callers updated.
	Update comments.  Compose dummy_frame_id and pass it to
	lookup_dummy_frame.
	(dummy_frame_discard): Add parameter ptid.
	(dummy_frame_sniffer): Compose dummy_frame_id and call
	dummy_frame_id_eq instead of frame_id_eq.
	(fprint_dummy_frames): Print ptid.
	* dummy-frame.h: Remove comments.
	(dummy_frame_push): Add ptid in declaration.
	(dummy_frame_pop, dummy_frame_discard): Likewise.

gdb/testsuite:

2014-06-27  Yao Qi  <yao@codesourcery.com>

	* gdb.multi/dummy-frame-restore.exp: New.
	* gdb.multi/dummy-frame-restore.c: New.

gdb/doc:

2014-06-27  Yao Qi  <yao@codesourcery.com>

	* gdb.texinfo (Maintenance Commands): Update the output of
	'maint print dummy-frames' command.