[DTrace-devel] [PATCH] test: Test disassembly annotation of variable access

[Eugene Loh]

On 1/27/22 1:57 PM, Kris Van Hees wrote:

> Two things...
>
> 1. Please update the tests to match the one I have for TLS vars in my patch
>     (for consistency).

Yup.  Indeed, the tests are based off of yours.  So they are already 
very similar.  However,

*)  You look for a very distinctive BPF instruction:  "call 
dt_get_tvar".  This trick works for tvars, but not for other kinds of 
variables, which use rather general ld/st instructions.  So I rename the 
variable to something more distinctive and look for that distinctive 
variable name.

*)  You print out the entire BPF instruction.  This works for tvars, but 
not for other kinds of variables.  For lvars and gvars, there is no 
common function call (like dt_get_tvar).  Rather, there is a rather 
common BPF instruction (like ldw or stw) that references specific 
registers and specific offsets.  It seemed to me that we would not want 
to be overly dependent on details of code generation, test script, etc.  
So I just print out the BPF operation, not including its operands.

*)  You only test "set".  Arguably, this is sufficient for tvars, where 
both "set" and "get" currently use dt_get_tvar().  For lvars and gvars, 
however, different instructions are generated for "set" and "get".  So I 
test both "set" and "get".

So, the tests are indeed intended to match what you had, with variations 
introduced only to generalize beyond just the TLS case.

> 2. No need to do TLS vars (tvar) because I already have that one in my patch.

Like you, I figured consistency would be a good thing.  We can first 
settle the lvar/gvar cases and then decide whether tvar should be 
similar or different.

> On Thu, Jan 27, 2022 at 01:34:25PM -0500, eugene.loh--- via DTrace-devel wrote:
>> From: Eugene Loh <eugene.loh at oracle.com>
>>
>> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
>> ---
>>   test/unittest/variables/gvar/tst.dis-ann.r  |  2 ++
>>   test/unittest/variables/gvar/tst.dis-ann.sh | 20 ++++++++++++++++++++
>>   test/unittest/variables/lvar/tst.dis-ann.r  |  2 ++
>>   test/unittest/variables/lvar/tst.dis-ann.sh | 20 ++++++++++++++++++++
>>   test/unittest/variables/tvar/tst.dis-ann.r  |  2 ++
>>   test/unittest/variables/tvar/tst.dis-ann.sh | 20 ++++++++++++++++++++
>>   6 files changed, 66 insertions(+)
>>   create mode 100644 test/unittest/variables/gvar/tst.dis-ann.r
>>   create mode 100755 test/unittest/variables/gvar/tst.dis-ann.sh
>>   create mode 100644 test/unittest/variables/lvar/tst.dis-ann.r
>>   create mode 100755 test/unittest/variables/lvar/tst.dis-ann.sh
>>   create mode 100644 test/unittest/variables/tvar/tst.dis-ann.r
>>   create mode 100755 test/unittest/variables/tvar/tst.dis-ann.sh
>>
>> diff --git a/test/unittest/variables/gvar/tst.dis-ann.r b/test/unittest/variables/gvar/tst.dis-ann.r
>> new file mode 100644
>> index 00000000..95586362
>> --- /dev/null
>> +++ b/test/unittest/variables/gvar/tst.dis-ann.r
>> @@ -0,0 +1,2 @@
>> +ldw foo
>> +stw foo
>> diff --git a/test/unittest/variables/gvar/tst.dis-ann.sh b/test/unittest/variables/gvar/tst.dis-ann.sh
>> new file mode 100755
>> index 00000000..291c64e8
>> --- /dev/null
>> +++ b/test/unittest/variables/gvar/tst.dis-ann.sh
>> @@ -0,0 +1,20 @@
>> +#!/bin/bash
>> +#
>> +# Oracle Linux DTrace.
>> +# Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
>> +# Licensed under the Universal Permissive License v 1.0 as shown at
>> +# http://oss.oracle.com/licenses/upl.
>> +#
>> +
>> +dtrace=$1
>> +
>> +$dtrace $dt_flags -Sen '
>> +BEGIN
>> +{
>> +	foo = 42;
>> +	trace(foo);
>> +	exit(0);
>> +}
>> +' 2>&1 | awk '/foo/ && !/D type/ { print $8, $NF }'
>> +
>> +exit $?
>> diff --git a/test/unittest/variables/lvar/tst.dis-ann.r b/test/unittest/variables/lvar/tst.dis-ann.r
>> new file mode 100644
>> index 00000000..a10af5a8
>> --- /dev/null
>> +++ b/test/unittest/variables/lvar/tst.dis-ann.r
>> @@ -0,0 +1,2 @@
>> +ldw this->foo
>> +stw this->foo
>> diff --git a/test/unittest/variables/lvar/tst.dis-ann.sh b/test/unittest/variables/lvar/tst.dis-ann.sh
>> new file mode 100755
>> index 00000000..bf3b9b83
>> --- /dev/null
>> +++ b/test/unittest/variables/lvar/tst.dis-ann.sh
>> @@ -0,0 +1,20 @@
>> +#!/bin/bash
>> +#
>> +# Oracle Linux DTrace.
>> +# Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
>> +# Licensed under the Universal Permissive License v 1.0 as shown at
>> +# http://oss.oracle.com/licenses/upl.
>> +#
>> +
>> +dtrace=$1
>> +
>> +$dtrace $dt_flags -Sen '
>> +BEGIN
>> +{
>> +	this->foo = 42;
>> +	trace(this->foo);
>> +	exit(0);
>> +}
>> +' 2>&1 | awk '/foo/ && !/D type/ { print $8, $NF }'
>> +
>> +exit $?
>> diff --git a/test/unittest/variables/tvar/tst.dis-ann.r b/test/unittest/variables/tvar/tst.dis-ann.r
>> new file mode 100644
>> index 00000000..f02effb1
>> --- /dev/null
>> +++ b/test/unittest/variables/tvar/tst.dis-ann.r
>> @@ -0,0 +1,2 @@
>> +call self->foo
>> +call self->foo
>> diff --git a/test/unittest/variables/tvar/tst.dis-ann.sh b/test/unittest/variables/tvar/tst.dis-ann.sh
>> new file mode 100755
>> index 00000000..9d28ab3b
>> --- /dev/null
>> +++ b/test/unittest/variables/tvar/tst.dis-ann.sh
>> @@ -0,0 +1,20 @@
>> +#!/bin/bash
>> +#
>> +# Oracle Linux DTrace.
>> +# Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
>> +# Licensed under the Universal Permissive License v 1.0 as shown at
>> +# http://oss.oracle.com/licenses/upl.
>> +#
>> +
>> +dtrace=$1
>> +
>> +$dtrace $dt_flags -Sen '
>> +BEGIN
>> +{
>> +	self->foo = 42;
>> +	trace(self->foo);
>> +	exit(0);
>> +}
>> +' 2>&1 | awk '/foo/ && !/D type/ { print $8, $NF }'
>> +
>> +exit $?
>> -- 
>> 2.18.4
>>
>>
>> _______________________________________________
>> DTrace-devel mailing list
>> DTrace-devel at oss.oracle.com
>> https://oss.oracle.com/mailman/listinfo/dtrace-devel