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.

2 files changed, 133 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.multi/dummy-frame-restore.c b/gdb/testsuite/gdb.multi/dummy-frame-restore.c
new file mode 100644
index 0000000..118c541
--- /dev/null
+++ b/gdb/testsuite/gdb.multi/dummy-frame-restore.c
@@ -0,0 +1,36 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2014 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+static void
+f1 (void)
+{}
+
+static void
+f2 (void)
+{}
+
+void
+commonfun (void)
+{}
+
+int
+main (void)
+{
+  f1 ();
+  f2 ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.multi/dummy-frame-restore.exp b/gdb/testsuite/gdb.multi/dummy-frame-restore.exp
new file mode 100644
index 0000000..a47a0b1
--- /dev/null
+++ b/gdb/testsuite/gdb.multi/dummy-frame-restore.exp
@@ -0,0 +1,97 @@
+# Copyright 2014 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+standard_testfile .c
+set executable ${testfile}
+
+# The plain remote target can't do multiple inferiors.
+if [target_info exists use_gdb_stub] {
+    return
+}
+
+if {[prepare_for_testing $testfile.exp $testfile $srcfile {debug}]} {
+    return -1
+}
+
+# Inferior 1 stops at f1.
+
+if ![runto f1] then {
+    fail "Can't run to f1"
+    return 0
+}
+
+gdb_test "add-inferior -exec ${binfile}" \
+    "Added inferior 2.*" \
+    "add inferior 2 with -exec ${executable}"
+gdb_test "inferior 2" "witching to inferior 2 .*" "switch to inferior 2"
+
+delete_breakpoints
+
+# Inferior 2 stops at f2.
+
+if ![runto f2] then {
+    fail "Can't run to f2"
+    return 0
+}
+
+gdb_breakpoint commonfun
+
+# Check the stack bactrace in inferior INF.  PREFIX is the test
+# message prefix.
+
+proc check_bt { inf prefix } {
+    with_test_prefix "$prefix" {
+	gdb_test "bt 1" "#0  f$inf .*" "bt in inferior $inf"
+    }
+}
+
+# Do inferior call commonfun () in inferior 2 and inferior 1, but
+# finish it in inferior INF1 first and then inferior INF2.  Check
+# the stack backtrace in each inferior is still correct after
+# inferior call.
+
+proc test { inf1 inf2 } {
+
+    with_test_prefix "inf $inf1 first" {
+	gdb_test "inferior 2" "witching to inferior 2 .*" \
+	    "switch to inferior 2 (1)"
+	check_bt 2 "before infcall"
+	gdb_test "p commonfun()" "Breakpoint .*The program being debugged stopped while in a function called from GDB.*" "infcall in inferior 2"
+
+	gdb_test "inferior 1" "witching to inferior 1 .*" \
+	    "switch to inferior 1 (1)"
+	check_bt 1 "before infcall"
+	gdb_test "p commonfun()" "Breakpoint .*The program being debugged stopped while in a function called from GDB.*" "infcall in inferior 1"
+
+	gdb_test "maintenance print dummy-frames" ": id={stack=.*}.*: id=.*" \
+	    "two dummy frames"
+
+	gdb_test "inferior $inf1" "witching to inferior $inf1 .*" \
+	    "switch to inferior $inf1 (2)"
+	gdb_test "finish" "Run till exit from #0  commonfun .*" \
+	    "finish in inferior $inf1"
+	check_bt $inf1 "after infcall"
+
+	gdb_test "inferior $inf2" "witching to inferior $inf2 .*" \
+	    "switch to inferior $inf2 (2)"
+	gdb_test "finish" "Run till exit from #0  commonfun .*" \
+	    "finish in inferior $inf2"
+	check_bt $inf2 "after infcall"
+    }
+}
+
+# Do the test in different orders.
+test 1 2
+test 2 1