gdb/testsuite: support passing inferior arguments with native-gdbserver board

This patch makes it possible to run tests requiring passing arguments to
the inferior with the native-gdbserver board.  The end goal is to write
a test that verifies passing arguments to the inferior works, and to
have that test exercise inferior arguments passed on the gdbserver
command line, when using the native-gdbserver target board (in addition
to the other boards).  This is done in the next patch.

With the native-gdbserver target board, gdbserver is started in
gdb_reload (implemented in config/gdbserver.exp), called in gdb_run_cmd.
gdb_run_cmd already supposedly accepts inferior arguments (although that
feature does not seem to be used anywhere), which it passes to the `run`
command, for non-stub target boards.  I've changed gdb_run_cmd so that
it forwards these arguments to gdb_reload as well.  gdb_reload passes
them to gdbserver_run, and they eventually make their way to the
gdbserver command line.

gdb_run_cmd currently accepts `args` (the varargs of tcl), which means
it receives inferior arguments as a list.  This won't work with
arguments with spaces, because they will end up being formatted with
curly braces like this:

    % set args [list hello "with spaces" world]
    hello {with spaces} world
    % puts "run $args"
    run hello {with spaces} world

I've changed it to accept a single string that is passed to `run` and
gdb_reload.  I've done the same change in gdb_start_cmd and
gdb_starti_cmd, although these two are not used with native-gdbserver.

I've changed all gdb_reload implementations in the tree to accept a new
inferior_args argument, although most of them don't do anything with it
(and don't need to).  People maintaining target boards out of tree will
need to do the same.

I found two tests to adjust to avoid adding new failures or errors.
These tests needed new [use_gdb_stub] checks, because they rely on
having GDB run new processes.  These are guarded by a [target_info
exists noargs], which made them get skipped on native-gdbserver.  But
now that the native-gdbserver board supports args, this is no longer
enough.

Note that with this change, noargs and use_gdb_stub are orthogonal.  It
took me a moment to grasp this, so I thought I would spell out the
different possible situations:

- !noargs and !use_gdb_stub: inferior process started by gdb, can pass
  args
- noargs and !use_gdb_stub: inferior process started by gdb (perhaps
  through extended-remote protocol, the simulator, some other target),
  but that target doesn't support inferior arguments
- noargs and use_gdb_stub: inferior process started by some other
  program to which GDB connects using the remote protocol, that program
  does not support passing args to the inferior process
- !noargs and use_gdb_stub: inferior process started by some other
  program to which GDB connects u sing the remote protocol, that program
  supports passing args to the inferior process

gdb/testsuite/ChangeLog:

	* lib/gdb.exp (gdb_run_cmd): Change argument from args to
	inferior_args.  Pass it to gdb_reload.
	(gdb_start_cmd, gdb_starti_cmd): Change argument from args to
	inferior_args.
	(gdb_reload): Add inferior_args argument.
	* config/gdbserver.exp (gdb_reload): Add inferior_args argument,
	pass it to gdbserver_run.
	* boards/native-gdbserver.exp: Do not set noargs.
	* boards/native-extended-gdbserver.exp (gdb_reload): Add
	inferior_args argument.
	* boards/stdio-gdbserver-base.exp (gdb_reload): Likewise.
	* gdb.base/a2-run.exp: Check for use_gdb_stub.
	* gdb.base/args.exp: Likewise.

Change-Id: Ibda027c71867157852f34700342ab31edf39e4d8

8 files changed, 62 insertions, 24 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 201f268..5da102b 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,19 @@
+2020-05-25  Simon Marchi  <simon.marchi@efficios.com>
+
+	* lib/gdb.exp (gdb_run_cmd): Change argument from args to
+	inferior_args.  Pass it to gdb_reload.
+	(gdb_start_cmd, gdb_starti_cmd): Change argument from args to
+	inferior_args.
+	(gdb_reload): Add inferior_args argument.
+	* config/gdbserver.exp (gdb_reload): Add inferior_args argument,
+	pass it to gdbserver_run.
+	* boards/native-gdbserver.exp: Do not set noargs.
+	* boards/native-extended-gdbserver.exp (gdb_reload): Add
+	inferior_args argument.
+	* boards/stdio-gdbserver-base.exp (gdb_reload): Likewise.
+	* gdb.base/a2-run.exp: Check for use_gdb_stub.
+	* gdb.base/args.exp: Likewise.
+
 2020-05-25  Tom de Vries  <tdevries@suse.de>
 
 	* lib/gdb.exp (exec_is_pie): Add comment.
diff --git a/gdb/testsuite/boards/native-extended-gdbserver.exp b/gdb/testsuite/boards/native-extended-gdbserver.exp
index 465c1cc..3d5e782 100644
--- a/gdb/testsuite/boards/native-extended-gdbserver.exp
+++ b/gdb/testsuite/boards/native-extended-gdbserver.exp
@@ -102,7 +102,7 @@ proc gdb_file_cmd { arg } {
     return [extended_gdbserver_load_last_file]
 }
 
-proc gdb_reload { } {
+proc gdb_reload { {inferior_args {}} } {
     return [extended_gdbserver_load_last_file]
 }
 
diff --git a/gdb/testsuite/boards/native-gdbserver.exp b/gdb/testsuite/boards/native-gdbserver.exp
index f9a5072..823f5cf 100644
--- a/gdb/testsuite/boards/native-gdbserver.exp
+++ b/gdb/testsuite/boards/native-gdbserver.exp
@@ -27,9 +27,6 @@ load_board_description "local-board"
 # This gdbserver can only run a process once per session.
 set_board_info gdb,do_reload_on_run 1
 
-# There's no support for argument-passing (yet).
-set_board_info noargs 1
-
 set_board_info use_gdb_stub 1
 set_board_info exit_is_reliable 1
 
diff --git a/gdb/testsuite/boards/stdio-gdbserver-base.exp b/gdb/testsuite/boards/stdio-gdbserver-base.exp
index aafcf69..720e2e8 100644
--- a/gdb/testsuite/boards/stdio-gdbserver-base.exp
+++ b/gdb/testsuite/boards/stdio-gdbserver-base.exp
@@ -45,7 +45,7 @@ proc make_gdbserver_stdio_port {} {
     return "| [get_target_remote_pipe_cmd]"
 }
 
-proc gdb_reload { } {
+proc gdb_reload { {inferior_args {}} } {
     return [gdb_target_cmd "remote" [make_gdbserver_stdio_port]]
 }
 
diff --git a/gdb/testsuite/config/gdbserver.exp b/gdb/testsuite/config/gdbserver.exp
index cb053b6..a4e935f 100644
--- a/gdb/testsuite/config/gdbserver.exp
+++ b/gdb/testsuite/config/gdbserver.exp
@@ -36,12 +36,8 @@
 #	Unles you have a gdbserver that can handle multiple sessions.
 #
 #   set_board_info noargs 1
-#	At present there is no provision in the remote protocol
-#	for passing arguments.  This test framework does not
-#	address the issue, so it's best to set this variable
-#	in your baseboard configuration file.  
-#	FIXME: there's no reason why the test harness couldn't
-#	pass commandline args when it spawns gdbserver.
+#	Set this if the board does not support passing arguments to the
+#	inferior process.
 #
 #   set_board_info gdb,noinferiorio 1
 #	Neither the traditional gdbserver nor the one in libremote
@@ -77,8 +73,8 @@ proc gdbserver_gdb_load { } {
     return [gdbserver_spawn ""]
 }
 
-proc gdb_reload { } {
-    return [gdbserver_run ""]
+proc gdb_reload { {inferior_args {}} } {
+    return [gdbserver_run $inferior_args]
 }
 
 proc gdb_reconnect { } {
diff --git a/gdb/testsuite/gdb.base/a2-run.exp b/gdb/testsuite/gdb.base/a2-run.exp
index 2e8ed60..ea8f7ec 100644
--- a/gdb/testsuite/gdb.base/a2-run.exp
+++ b/gdb/testsuite/gdb.base/a2-run.exp
@@ -135,7 +135,7 @@ gdb_run_cmd 5
 gdb_test_stdio "" "120" "" "run \"$testfile\" with arg"
 
 # Run again with same arguments.
-gdb_run_cmd
+gdb_run_cmd 5
 
 setup_xfail "arm-*-coff"
 gdb_test_stdio "" "120" "" "run \"$testfile\" again with same args"
@@ -147,6 +147,15 @@ gdb_run_cmd
 
 gdb_test_stdio "" "usage:  factorial <number>" "" "run after setting args to nil"
 
+# The remaining tests pass inferior arguments through GDB, so doesn't
+# work with stub targets, where GDB connects to debug an already started
+# process.
+
+if [use_gdb_stub] {
+    verbose "Skipping rest of a2-run.exp because target is a stub."
+    return
+}
+
 # Use "set args" command to specify an argument and run again.
 gdb_test_no_output "set args 6"
 
diff --git a/gdb/testsuite/gdb.base/args.exp b/gdb/testsuite/gdb.base/args.exp
index 6c416fc..ee75445 100644
--- a/gdb/testsuite/gdb.base/args.exp
+++ b/gdb/testsuite/gdb.base/args.exp
@@ -23,6 +23,12 @@ if [target_info exists noargs] {
     return
 }
 
+# This test requires starting new inferior processes, skip it if the target
+# board is a stub.
+if [use_gdb_stub] {
+    return
+}
+
 standard_testfile
 
 if {[build_executable $testfile.exp $testfile \
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 8e22941..b2b717f 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -246,10 +246,13 @@ proc target_can_use_run_cmd {} {
 # Using ``.*$'' could swallow up output that we attempt to match
 # elsewhere.
 #
+# INFERIOR_ARGS is passed as arguments to the start command, so may contain
+# inferior arguments.
+#
 # N.B. This function does not wait for gdb to return to the prompt,
 # that is the caller's responsibility.
 
-proc gdb_run_cmd {args} {
+proc gdb_run_cmd { {inferior_args {}} } {
     global gdb_prompt use_gdb_stub
 
     foreach command [gdb_init_commands] {
@@ -265,7 +268,7 @@ proc gdb_run_cmd {args} {
 
     if $use_gdb_stub {
 	if [target_info exists gdb,do_reload_on_run] {
-	    if { [gdb_reload] != 0 } {
+	    if { [gdb_reload $inferior_args] != 0 } {
 		return
 	    }
 	    send_gdb "continue\n"
@@ -310,7 +313,7 @@ proc gdb_run_cmd {args} {
 		    send_gdb "y\n" answer
 		}
 		-re "The program is not being run.*$gdb_prompt $" {
-		    if { [gdb_reload] != 0 } {
+		    if { [gdb_reload $inferior_args] != 0 } {
 			return
 		    }
 		    send_gdb "jump *$start\n"
@@ -325,11 +328,11 @@ proc gdb_run_cmd {args} {
     }
 
     if [target_info exists gdb,do_reload_on_run] {
-	if { [gdb_reload] != 0 } {
+	if { [gdb_reload $inferior_args] != 0 } {
 	    return
 	}
     }
-    send_gdb "run $args\n"
+    send_gdb "run $inferior_args\n"
 # This doesn't work quite right yet.
 # Use -notransfer here so that test cases (like chng-sym.exp)
 # may test for additional start-up messages.
@@ -348,10 +351,13 @@ proc gdb_run_cmd {args} {
 # Generic start command.  Return 0 if we could start the program, -1
 # if we could not.
 #
+# INFERIOR_ARGS is passed as arguments to the start command, so may contain
+# inferior arguments.
+#
 # N.B. This function does not wait for gdb to return to the prompt,
 # that is the caller's responsibility.
 
-proc gdb_start_cmd {args} {
+proc gdb_start_cmd { {inferior_args {}} } {
     global gdb_prompt use_gdb_stub
 
     foreach command [gdb_init_commands] {
@@ -369,7 +375,7 @@ proc gdb_start_cmd {args} {
 	return -1
     }
 
-    send_gdb "start $args\n"
+    send_gdb "start $inferior_args\n"
     # Use -notransfer here so that test cases (like chng-sym.exp)
     # may test for additional start-up messages.
     gdb_expect 60 {
@@ -387,10 +393,13 @@ proc gdb_start_cmd {args} {
 # Generic starti command.  Return 0 if we could start the program, -1
 # if we could not.
 #
+# INFERIOR_ARGS is passed as arguments to the starti command, so may contain
+# inferior arguments.
+#
 # N.B. This function does not wait for gdb to return to the prompt,
 # that is the caller's responsibility.
 
-proc gdb_starti_cmd {args} {
+proc gdb_starti_cmd { {inferior_args {}} } {
     global gdb_prompt use_gdb_stub
 
     foreach command [gdb_init_commands] {
@@ -408,7 +417,7 @@ proc gdb_starti_cmd {args} {
 	return -1
     }
 
-    send_gdb "starti $args\n"
+    send_gdb "starti $inferior_args\n"
     gdb_expect 60 {
 	-re "The program .* has been started already.*y or n. $" {
 	    send_gdb "y\n" answer
@@ -4818,8 +4827,13 @@ proc gdb_load { arg } {
 # either the first time or after already starting the program once,
 # for remote targets.  Most files that override gdb_load should now
 # override this instead.
+#
+# INFERIOR_ARGS contains the arguments to pass to the inferiors, as a
+# single string to get interpreted by a shell.  If the target board
+# overriding gdb_reload is a "stub", then it should arrange things such
+# these arguments make their way to the inferior process.
 
-proc gdb_reload { } {
+proc gdb_reload { {inferior_args {}} } {
     # For the benefit of existing configurations, default to gdb_load.
     # Specifying no file defaults to the executable currently being
     # debugged.