[gdb/testsuite] Set remotedir by default in some boards

When doing a gdb_simple_compile, and downloading the resulting exec $obj
to target the result $target_obj may be a relative file path, which may give
problems when trying to do:
...
remote_exec target $target_obj
...

Fix/workaround this on some target boards by setting remotedir by default, and
add a corresponding test in gdb.testsuite/board-sanity.exp.

This doesn't work for host/target board local-remote-host-native, so xfail this.

Tested on x86_64-linux.

gdb/testsuite/boards/remote-gdbserver-on-localhost.exp

@@ -37,22 +37,35 @@ if { [info exists REMOTE_TARGET_USERNAME] } {
 }
 set_board_info hostname localhost
 
-# Handle separate test account.
+save_vars {rsh_cmd res} {
-if { [board_info $board username] != $env(USER) } {
+    set rsh_cmd \
-    # We're pretending that some local user account is remote target.
+	[join \
-    # Make things a bit more realistic by restricting file permissions.
+	     [list \
+		  [board_info $board rsh_prog] \
+		  -l [board_info $board username] \
+		  [board_info $board hostname]]]
 
-    # Make sure remote target can't see files on build.
+    # Handle separate test account.
-    remote_exec build "chmod go-rx $objdir"
+    if { [board_info $board username] != $env(USER) } {
+	# We're pretending that some local user account is remote target.
+	# Make things a bit more realistic by restricting file permissions.
 
-    # Make sure build can't see files on remote target.  We can't use
+	# Make sure remote target can't see files on build.
-    # remote_exec target, because we're in the middle of parsing the
+	remote_exec build "chmod go-rx $objdir"
-    # target board.
+
-    remote_exec build \
+	# Make sure build can't see files on remote target.  We can't use
-	"[board_info $board rsh_prog] \
+	# remote_exec target, because we're in the middle of parsing the
-		     -l [board_info $board username] \
+	# target board.
-			[board_info $board hostname] \
+	remote_exec build $rsh_cmd chmod go-rx ."
-	chmod go-rx ."
+    }
+
+    # Set remotedir by default, to force remote_download target to give an
+    # absolute file name.
+    set res [remote_exec build $rsh_cmd pwd]
+    if { [lindex $res 0] != 0 } {
+	error "Couldn't set remotedir using pwd"
+    }
+    set_board_info remotedir [string trim [lindex $res 1]]
 }
 
 proc ${board}_file { dest op args } {

gdb/testsuite/boards/remote-stdio-gdbserver.exp

@@ -45,6 +45,22 @@ set_board_info rcp_prog /usr/bin/scp
 # Some remote machines don't have writable home directories.
 if [info exists REMOTE_TMPDIR] {
     set_board_info remotedir $REMOTE_TMPDIR
+} else {
+    # Set remotedir by default, to force remote_download target to give an
+    # absolute file name.
+    save_vars {rsh_cmd res} {
+	set rsh_cmd \
+	    [join \
+		 [list \
+		      [board_info $board rsh_prog] \
+		      -l [board_info $board username] \
+		      [board_info $board hostname]]]
+	set res [remote_exec build $rsh_cmd pwd]
+	if { [lindex $res 0] != 0 } {
+	    error "Couldn't set remotedir using pwd"
+	}
+	set_board_info remotedir [string trim [lindex $res 1]]
+    }
 }
 
 if [info exists GDBSERVER] {

gdb/testsuite/gdb.testsuite/board-sanity.exp

@@ -120,3 +120,35 @@ foreach_with_prefix remote {host target} {
 	test_remote $remote $host_is_target
     }
 }
+
+proc_with_prefix gdb_simple_compile_and_run {} {
+    set src {
+	int main() {
+	    return 0;
+	}
+    }
+
+    set test "compile"
+    if {![gdb_simple_compile board-sanity $src executable]} {
+	fail $test
+	return
+    }
+    pass $test
+
+    set target_obj [gdb_remote_download target $obj]
+    set result [remote_exec target $target_obj]
+    set status [lindex $result 0]
+    set output [lindex $result 1]
+
+    if { [host_info name] == "local-remote-host-native"
+	 && [target_info name] == "local-remote-host-native" } {
+	# Setting remotedir on this board has effect on both host and
+	# target, and it seems to broken for host.  Xfail this for now.
+	setup_xfail *-*-*
+    }
+    gdb_assert { $status == 0 && $output == "" }
+
+    remote_file build delete $obj
+}
+
+gdb_simple_compile_and_run