Re: [PATCH][gdb/testsuite] Fix gdb.btrace/tsx.exp on system with tsx disabled in microcode

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

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On 7/12/21 1:54 PM, Metzger, Markus T wrote:
> Hello Tom,
> 
> 
>> diff --git a/gdb/testsuite/gdb.btrace/tsx.exp b/gdb/testsuite/gdb.btrace/tsx.exp
>> index ccde1ea807e..7f96313f1b1 100644
>> --- a/gdb/testsuite/gdb.btrace/tsx.exp
>> +++ b/gdb/testsuite/gdb.btrace/tsx.exp
>> @@ -59,6 +59,11 @@ set abort_2 [multi_line \
>>     "\[0-9\]*\t   0x\[0-9a-f\]+ <test\\+\[0-9\]+>:\tmov\[^\\\r\\\n\]*" \
>>     "\[0-9\]*\t   0x\[0-9a-f\]+ <test\\+\[0-9\]+>:\tret\[^\\\r\\\n\]*" \
>>     ]
>> +set abort_3 \
>> +    [multi_line \
>> +	 "$decimal\t   $hex <main\\+$decimal>:\tcall\[^\\\r\\\n\]*" \
>> +	 "$decimal\t   $hex <test\\+$decimal>:\tmov\[^\\\r\\\n\]*" \
>> +	 "$decimal\t   $hex <test\\+$decimal>:\tret\[^\\\r\\\n\]*"]
> 
> The patterns do not include the call since this is compiler-generated.  The actual
> TSX test is written in assembly so we know the instructions.
> 

I see.  Fixed by not requiring a specific instruction.

> 
>> set test "speculation indication"
>> gdb_test_multiple "record instruction-history" $test {
>> @@ -68,6 +73,9 @@ gdb_test_multiple "record instruction-history" $test {
>>     -re "$abort_2.*$gdb_prompt $" {
>>         pass $test
>>     }
>> +    -re -wrap "$abort_3" {
>> +        pass $gdb_test_name
>> +    }
> 
> Does this '-wrap' add ".*$gdb_prompt $"?
> 
> Note that we need the ".*" after the pattern since this code is compiler-generated
> and we don't really know when we will stop after returning from test ().


The -wrap processes the pattern in exactly the same way as gdb_test does:
...
        if { $wrap_pattern } {
            # Wrap subst_item as is done for the gdb_test PATTERN
            # argument.
            lappend $current_list \
                "\[\r\n\]*(?:$subst_item)\[\r\n\]+$gdb_prompt $"
            set wrap_pattern 0
        } else {
...

After running with clang, I ran into the FAIL you anticipated, which is
indeed fixed by adding .* in the pattern.

Updated patch attached.  OK for trunk?

Thanks,
- Tom


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[gdb/testsuite] Fix gdb.btrace/tsx.exp on system with tsx disabled in microcode

Recently I started to see this fail with trunk:
...
(gdb) record instruction-history^M
1          0x00000000004004ab <main+4>: call   0x4004b7 <test>^M
2          0x00000000004004c6 <test+15>:        mov    $0x1,%eax^M
3          0x00000000004004cb <test+20>:        ret    ^M
(gdb) FAIL: gdb.btrace/tsx.exp: speculation indication
...

This is due to an intel microcode update (1) that disables Intel TSX by default.

Fix this by updating the pattern.

Tested on x86_64-linux, with both gcc 7.5.0 and clang 12.0.1.

[1] https://www.intel.com/content/www/us/en/support/articles/000059422/processors.html

gdb/testsuite/ChangeLog:

2021-07-12  Tom de Vries  <tdevries@suse.de>

	PR testsuite/28057
	* gdb.btrace/tsx.exp: Add pattern for system with tsx disabled in
	microcode.

---
 gdb/testsuite/gdb.btrace/tsx.exp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/gdb/testsuite/gdb.btrace/tsx.exp b/gdb/testsuite/gdb.btrace/tsx.exp
index ccde1ea807e..66f6305e50a 100644
--- a/gdb/testsuite/gdb.btrace/tsx.exp
+++ b/gdb/testsuite/gdb.btrace/tsx.exp
@@ -59,6 +59,11 @@ set abort_2 [multi_line \
     "\[0-9\]*\t   0x\[0-9a-f\]+ <test\\+\[0-9\]+>:\tmov\[^\\\r\\\n\]*" \
     "\[0-9\]*\t   0x\[0-9a-f\]+ <test\\+\[0-9\]+>:\tret\[^\\\r\\\n\]*" \
     ]
+set abort_3 \
+    [multi_line \
+	 "$decimal\t   $hex <main\\+$decimal>:\t\[^\\\r\\\n\]*" \
+	 "$decimal\t   $hex <test\\+$decimal>:\tmov\[^\\\r\\\n\]*" \
+	 "$decimal\t   $hex <test\\+$decimal>:\tret\[^\\\r\\\n\]*"]
 
 set test "speculation indication"
 gdb_test_multiple "record instruction-history" $test {
@@ -68,6 +73,9 @@ gdb_test_multiple "record instruction-history" $test {
     -re "$abort_2.*$gdb_prompt $" {
         pass $test
     }
+    -re -wrap "$abort_3.*" {
+        pass $gdb_test_name
+    }
     -re  "$begin_to_end.*$gdb_prompt $" {
         pass $test
     }