In the original (nested) case, if an inner if-statement fails, the outer
else-if is never evaluated, whereas in my version, it is.
On 2013-09-06 5:20 PM, "jingham at apple.com" <jingham at apple.com> wrote:
>I must be dense today, but I can't see any logical difference between the
>version in your patch and the one that was there before.
>
>Jim
>
>On Sep 6, 2013, at 2:03 PM, Malea, Daniel <daniel.malea at intel.com> wrote:
>
>> Hi Ed/Jim,
>>
>> After this fix, I'm noticing some buildbot failures in
>> TestInlineStepping.py, which I reproduced locally:
>>
>> Process 25548 stopped
>> * thread #1: tid = 25548, 0x0000000000400721 a.out`main(argc=1,
>> argv=0x00007fffd73b7b38) + 33 at calling.cpp:106, name = 'a.out', stop
>> reason = step over
>> frame #0: 0x0000000000400721 a.out`main(argc=1,
>>argv=0x00007fffd73b7b38)
>> + 33 at calling.cpp:106
>> 103
>> 104 inline_value = 0; // Stop here and step over to set up
>> stepping over.
>> 105
>> -> 106 inline_trivial_1 (); // At inline_trivial_1 called from
>> main.
>> 107
>> 108 caller_trivial_1(); // At first call of caller_trivial_1
>>in
>> main.
>> 109
>> (lldb) thread step-over
>> Process 25548 stopped
>> * thread #1: tid = 25548, 0x0000000000400728 a.out`main [inlined]
>> inline_trivial_2() + 7 at calling.cpp:96, name = 'a.out', stop reason =
>> step over
>> frame #0: 0x0000000000400728 a.out`main [inlined] inline_trivial_2() +
>>7
>> at calling.cpp:96
>> 93 void
>> 94 inline_trivial_2 ()
>> 95 {
>> -> 96 inline_value += 1; // In inline_trivial_2.
>> 97 called_by_inline_trivial (); // At caller_by_inline_trivial in
>> inline_trivial_2.
>> 98 }
>> 99
>> (lldb)
>>
>>
>>
>> It looks like the call to step-over the call on line 106 results in LLDB
>> stopping two levels of inlined functions inside the call to
>> inline_trivial_1(), rather than the line after the call to
>> inline_trivial_1() as the user would expect..
>>
>> Debugging the broken 'thread step-out' through the location in
>> ThreadPlanStepOverRange.cpp that was modified in 190149, I noticed that
>> while m_addr_context and older_context had equal comp_unit, function and
>> symbol members, the block members were not equal. Due to the way the
>> if-statement is nested, older_ctx_is_equivalent remains false and leads
>>to
>> the buggy behaviour. I have a potential fix (please see attached patch)
>>--
>> Jim when you have a moment, can you comment on the validity of the fix?
>>I
>> am not seeing any other regressions with my patch applied (with either
>> clang trunk or gcc 4.7).
>>
>>
>> Thanks,
>> Dan
>>
>> On 2013-09-06 8:43 AM, "Ed Maste" <emaste at freebsd.org> wrote:
>>
>>> Author: emaste
>>> Date: Fri Sep 6 07:43:14 2013
>>> New Revision: 190149
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=190149&view=rev
>>> Log:
>>> Correct logic error found by inspection.
>>>
>>> From Jim's post on the lldb-dev mailing list:
>>>
>>> This code is there as a backstop for when the unwinder drops a frame at
>>> the beginning of new function/trampoline or whatever.
>>>
>>> In the (older_ctx_is_equivalent == false) case we will see if we are at
>>> a trampoline function that somebody knows how to get out of, and
>>> otherwise we will stop.
>>>
>>> Modified:
>>> lldb/trunk/source/Target/ThreadPlanStepOverRange.cpp
>>>
>>> Modified: lldb/trunk/source/Target/ThreadPlanStepOverRange.cpp
>>> URL:
>>>
>>>http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Target/ThreadPlanS
>>>te
>>> pOverRange.cpp?rev=190149&r1=190148&r2=190149&view=diff
>>>
>>>========================================================================
>>>==
>>> ====
>>> --- lldb/trunk/source/Target/ThreadPlanStepOverRange.cpp (original)
>>> +++ lldb/trunk/source/Target/ThreadPlanStepOverRange.cpp Fri Sep 6
>>> 07:43:14 2013
>>> @@ -121,7 +121,7 @@ ThreadPlanStepOverRange::ShouldStop (Eve
>>> // in so I left out the target check. And sometimes the
>>> module comes in as the .o file from the
>>> // inlined range, so I left that out too...
>>>
>>> - bool older_ctx_is_equivalent = true;
>>> + bool older_ctx_is_equivalent = false;
>>> if (m_addr_context.comp_unit)
>>> {
>>> if (m_addr_context.comp_unit == older_context.comp_unit)
>>>
>>>
>>> _______________________________________________
>>> lldb-commits mailing list
>>> lldb-commits at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-commits
>>
>> <older_ctx_equivalent_inline_stepping_fix.patch>
>