Eliminate is_remote check in gdb.base/scope.exp

This commit makes --target_board=native-gdbserver (and in principle
all other is_remote boards) pass all the same gdb.base/scope.exp tests
as native testing.

I first wrote the gdb.base/scope.exp change described in the ChangeLog
below and in the new comments in the patch, knowing that gdb_file_cmd
was the right thing to use here.

However, that revealed that the native-extended-gdbserver board should
be overriding gdb_file_cmd+gdb_reload instead of gdb_load, as is
hinted at by the comments on top of the default implementations in
testsuite/lib/gdb.exp, because otherwise a gdb_run_cmd after
gdb_file_cmd misses setting "set remote exec-file".  However, if we do
that and remove gdb_load, then we regress gdb.base/dbx.exp, so for now
keep the gdb_load override as well.

gdb/testsuite/ChangeLog:
2017-10-13  Pedro Alves  <palves@redhat.com>

	* gdb.base/scope.exp: Use build_executable + clean_restart +
	gdb_file_cmd instead of prepare_for_testing and no longer skip
	"before run" tests on is_remote target boards.  Update comments.
	* boards/native-extended-gdbserver.exp
	(extended_gdbserver_load_last_file): New, factored out from ...
	(gdb_load): ... this.  Move further below and add comment.
	(extended_gdbserver_gdb_file_cmd, gdb_file_cmd, gdb_reload): New.

1 files changed, 34 insertions, 8 deletions

diff --git a/gdb/testsuite/boards/native-extended-gdbserver.exp b/gdb/testsuite/boards/native-extended-gdbserver.exp
index 4ea210f095..564ffd2229 100644
--- a/gdb/testsuite/boards/native-extended-gdbserver.exp
+++ b/gdb/testsuite/boards/native-extended-gdbserver.exp
@@ -80,17 +80,12 @@ proc mi_gdb_start { args } {
     return 0
 }
 
-# Overriden in order to set the remote exec-file whenever a file is
-# loaded to gdb.
-#
-proc gdb_load { arg } {
+# Helper that runs "set remote exec-file" with the last loaded file.
+
+proc extended_gdbserver_load_last_file {} {
     global gdb_prompt
     global last_loaded_file
 
-    if { $arg != "" } {
-	if [gdb_file_cmd $arg] then { return -1 }
-    }
-
     send_gdb "set remote exec-file $last_loaded_file\n"
     gdb_expect {
 	-re "$gdb_prompt $" {}
@@ -103,6 +98,37 @@ proc gdb_load { arg } {
     return 0
 }
 
+# Overriden in order to set the remote exec-file whenever a file is
+# loaded to gdb.
+#
+if { [info procs extended_gdbserver_gdb_file_cmd] == "" } {
+    rename gdb_file_cmd extended_gdbserver_gdb_file_cmd
+}
+proc gdb_file_cmd { arg } {
+    if [extended_gdbserver_gdb_file_cmd $arg] {
+	return -1
+    }
+    return [extended_gdbserver_load_last_file]
+}
+
+proc gdb_reload { } {
+    return [extended_gdbserver_load_last_file]
+}
+
+# With the two procedure overrides above, it shouldn't be necessary to
+# override this one too.  However, not doing so regresses
+# gdb.base/dbx.exp.  See comments above gdb.base/dbx.exp:gdb_file_cmd.
+# Once testing of the "symbol-file"/"exec-file" commands is moved out
+# to a separate non-dbx testcase, we should be able to remove this.
+proc gdb_load { arg } {
+    if { $arg != "" } {
+	if [gdb_file_cmd $arg] then { return -1 }
+    }
+
+    return [extended_gdbserver_load_last_file]
+}
+
+
 # Likewise, for MI.
 #
 if { [info procs extended_gdbserver_mi_gdb_load] == "" } {