[committed][gdb/testsuite] Make gdb.base/dbx.exp more robust

Tom de Vries
2020-06-11T12:12:00Z

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[ was: Re: [PATCH 3/3][gdb/testsuite] Warn about leaked global array ]

On 04-06-2020 13:40, Tom de Vries wrote:
>> BTW, global variables alone aren't the full scope of the
>> bleeding between testcases. There's also the case of
>> testcases overriding procedures, like gdb.base/dbx.exp,
>> but those are perhaps rare enough that we can continue
>> handling it "manually" as before.
> AFAICT, that test-case does an effort to undo the override, though I'm
> not sure how certain it is that the undo will be executed.

I've committed patch below to make sure the undo is executed (and
similar for GDBFLAGS).

Thanks,
- Tom

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[gdb/testsuite] Make gdb.base/dbx.exp more robust

Test-case gdb.base/dbx.exp overrides:
- the GDBFLAGS variable
- the gdb_file_cmd proc

There's code at the end of the test-case to restore both, but that's not
guaranteed to be executed.

Fix this by:
- using save_vars to restore GDBFLAGS
- using a new proc with_override to restore gdb_file_cmd

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2020-06-11 Tom de Vries <tdevries@suse.de>

* lib/gdb.exp (with_override): New proc, factored out of ...
* gdb.base/dbx.exp: ... here. Use with_override and save_vars.

---
gdb/testsuite/gdb.base/dbx.exp | 35 ++++++++++++++++------------------
gdb/testsuite/lib/gdb.exp | 43 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 59 insertions(+), 19 deletions(-)

diff --git a/gdb/testsuite/gdb.base/dbx.exp b/gdb/testsuite/gdb.base/dbx.exp
index 4299c44368..2a53f99a28 100644
--- a/gdb/testsuite/gdb.base/dbx.exp
+++ b/gdb/testsuite/gdb.base/dbx.exp
@@ -147,11 +147,8 @@ proc dbx_reinitialize_dir { subdir } {
# right sequence of events, allowing gdb_load to do its normal thing? This way
# remotes and simulators will work, too.
#
-# [drow 2002-03-30]: We can restore the old gdb_file_cmd afterwards, though.
-set old_gdb_file_cmd_args [info args gdb_file_cmd]
-set old_gdb_file_cmd_body [info body gdb_file_cmd]

-proc gdb_file_cmd {arg} {
+proc local_gdb_file_cmd {arg} {
global loadpath
global loadfile
global GDB
@@ -286,24 +283,24 @@ proc test_func { } {
# Start with a fresh gdb.

gdb_exit
-global GDBFLAGS
-set saved_gdbflags $GDBFLAGS

-set GDBFLAGS "$GDBFLAGS --dbx"
-gdb_start
-dbx_reinitialize_dir $srcdir/$subdir
-gdb_load ${binfile}
+with_override gdb_file_cmd local_gdb_file_cmd {
+ save_vars GDBFLAGS {
+ set GDBFLAGS "$GDBFLAGS --dbx"

-test_breakpoints
-test_assign
-test_whereis
-gdb_test "file average.c:1" "1\[ \t\]+/. This is a sample program.*"
-test_func
+ gdb_start
+ dbx_reinitialize_dir $srcdir/$subdir
+ gdb_load ${binfile}

-#exit and cleanup
-gdb_exit
+ test_breakpoints
+ test_assign
+ test_whereis
+ gdb_test "file average.c:1" "1\[ \t\]+/. This is a sample program.*"
+ test_func

-set GDBFLAGS $saved_gdbflags
-eval proc gdb_file_cmd {$old_gdb_file_cmd_args} {$old_gdb_file_cmd_body}
+ #exit and cleanup
+ gdb_exit
+ }
+}

return 0
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 9a0620a2bf..51f8a05464 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -7200,5 +7200,48 @@ proc hex_in_list { val hexlist } {
return [expr $index != -1]
}

+# Override proc NAME to proc OVERRIDE for the duration of the execution of
+# BODY.
+
+proc with_override { name override body } {
+ # Implementation note: It's possible to implement the override using
+ # rename, like this:
+ # rename $name save_$name
+ # rename $override $name
+ # set code [catch {uplevel 1 $body} result]
+ # rename $name $override
+ # rename save_$name $name
+ # but there are two issues here:
+ # - the save_$name might clash with an existing proc
+ # - the override is no longer available under its original name during
+ # the override
+ # So, we use this more elaborate but cleaner mechanism.
+
+ # Save the old proc.
+ set old_args [info args $name]
+ set old_body [info body $name]
+
+ # Install the override.
+ set new_args [info args $override]
+ set new_body [info body $override]
+ eval proc $name {$new_args} {$new_body}
+
+ # Execute body.
+ set code [catch {uplevel 1 $body} result]
+
+ # Restore old proc.
+ eval proc $name {$old_args} {$old_body}
+
+ # Return as appropriate.
+ if { $code == 1 } {
+ global errorInfo errorCode
+ return -code error -errorinfo $errorInfo -errorcode $errorCode $result
+ } elseif { $code > 1 } {
+ return -code $code $result
+ }
+
+ return $result
+}
+
# Always load compatibility stuff.
load_lib future.exp