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

[Tom de Vries <tdevries@suse.de>]

On 03-06-2020 12:09, Tom de Vries wrote:
> On 03-06-2020 11:38, Tom de Vries wrote:
>> On 03-06-2020 10:47, Tom de Vries wrote:
>>> ERROR: can't read "mi_gdb_prompt": no such variable
>>>     while executing
>>> "expect {
>>> -i exp95 -timeout 10
>>>         -re "~\"GNU.*\r\n~\".*$mi_gdb_prompt$" {
>>>             # We have a new format mi startup prompt.  If we are
>>>             # running mi1,..."
>>>     ("uplevel" body line 1)
>>>     invoked from within
>>> "uplevel $body" TCL READ VARNAME can't read "mi_gdb_prompt": no such
>>> variable
>>
>> So, the following happens:
>> - a test-case imports mi-support.exp using load_lib
>> - mi-support.exp sets mi_gdb_prompt
>> - the test-case finishes and the new global mi_gdb_prompt is unset,
>>   because it was not set before the test-case
>> - a next test-case imports mi-support.exp using load_lib
>> - load_lib sees that the file already has been loaded, so it skips it
>> - mi_gdb_prompt remains unset
>> - the test-case uses mi_gdb_prompt, and we have an error.
> 
> This naive solution seems to work.
> 
> Perhaps we can override load_lib to do the same, automatically.
> 

That seems to work, I'll test this through.

Thanks,
- Tom

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 66de9d6be3..bca47b96f2 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -25,6 +25,39 @@ if {$tool == ""} {
     exit 2
 }

+rename load_lib saved_load_lib
+
+array set gdb_persistent_globals {}
+
+proc gdb_persistent_global { varname } {
+    global gdb_persistent_globals
+    set gdb_persistent_globals($varname) 1
+}
+
+proc load_lib { file } {
+    array set known_global {}
+    foreach varname [info globals] {
+       set known_globals($varname) 1
+    }
+
+    set code [catch "saved_load_lib $file" result]
+
+    foreach varname [info globals] {
+       if { ![info exists known_globals($varname)] } {
+           gdb_persistent_global $varname
+       }
+    }
+
+    if {$code == 1} {
+       global errorInfo errorCode
+       return -code error -errorinfo $errorInfo -errorcode $errorCode
$result
+    } elseif {$code > 1} {
+       return -code $code $result
+    }
+
+    return $result
+}
+
 load_lib libgloss.exp
 load_lib cache.exp
 load_lib gdb-utils.exp
@@ -5114,10 +5147,14 @@ proc gdb_setup_known_globals {} {
 # GDB_KNOWN_GLOBALS array is unset, this ensures we don't "leak"
 # globals from one test script to another.
 proc gdb_cleanup_globals {} {
-    global gdb_known_globals
+    global gdb_known_globals gdb_persistent_globals

     foreach varname [info globals] {
        if {![info exists gdb_known_globals($varname)]} {
+           if { [info exists gdb_persistent_globals($varname)] } {
+               continue
+           }
+           verbose -log "gdb_cleanup_globals: deleting $varname"
            uplevel #0 unset $varname
        }
     }