[llvm-commits] [PATCH] Preserve DebugInfo during LICM

[Devang Patel]

2009/10/13 Török Edwin <edwintorok at gmail.com>:
> On 2009-10-13 20:16, Devang Patel wrote:
>> 2009/10/11 Török Edwin <edwintorok at gmail.com>:
>>
>>>>> I think that we'd need another TEST.dbgquality that tests whether each
>>>>> basicblock has at least one stoppoint (if original did),
>>>>> and also outputs how many instructions have a stoppoint in same BB, how
>>>>> many have a stoppoint
>>>>> foundable by findStopPointInst, and how many don't have at all. The test
>>>>> would pass if each BB has at least one stoppoint,
>>>>>
>>>> I'm not sure what the right approach is here.  When stoppoints move to
>>>> being on the instructions, we won't really need this.
>>>>
>>> We'd need something else:  check that each insn has a debug info, some
>>> optimizers may create new instructions and forget
>>> to set debug info.
>>>
>>> But you're right, there is no point working on this now, since the debug
>>> info is about to undergo a major change.
>>>
>>>
>>
>> Now, debug info (location info) is attached to an instruction. There
>> is a way to check this.
>>
>>   MetadataContext &TheMetadata = ...getContext().getMetadata();
>>   unsigned MDDbgKind = TheMetadata.getMDKind("dbg");
>>   if (MDNode *Dbg = TheMetadata.getMD(MDDbgKind, I)) {
>>
>
> Maybe I should update findStopPoint to return dbg metadata instead of a
> stoppoint, if stoppoints are going away?

Eventually yes. I'll wait for things to settle down before completely
removing this.
>
> If stoppoints are going away please let me know so I can update
> Analysis/DbgInfoPrinter.cpp too.
>> Here Dbg is non-null if debug info is attached with instruction I.
>>
>
> Does llvm-gcc and clang support emitting dbgmetadata on instructions?

Yes, I flipped the switch yesterday.

> If yes I'll start working on something that measures quality of dbginfo
> in the testsuite, and maybe do some checks too.

That'd be very useful.

> Also does this move to metadata on instructions fix the
> linker/inliner(?) bug where the line number was greater than the total
> lines in the file?

Not yet.

> And the bug that you can't link together multiple files with debug info
> due to multiple main compilation units?

Not yet.
-
Devang