[dragonegg] r186952 - The debug info verifier requires a non-empty name here. Pacify it.

[Eric Christopher]

On Tue, Jul 23, 2013 at 1:03 PM, Robinson, Paul
<Paul_Robinson at playstation.sony.com> wrote:
>> -----Original Message-----
>> From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-
>> bounces at cs.uiuc.edu] On Behalf Of David Blaikie
>> Sent: Tuesday, July 23, 2013 10:24 AM
>> To: Duncan Sands
>> Cc: llvm-commits at cs.uiuc.edu
>> Subject: Re: [dragonegg] r186952 - The debug info verifier requires a
>> non-empty name here. Pacify it.
>>
>> On Tue, Jul 23, 2013 at 10:20 AM, Duncan Sands <baldrick at free.fr> wrote:
>> > Hi David,
>> >
>> >
>> > On 23/07/13 19:01, David Blaikie wrote:
>> >>
>> >> On Tue, Jul 23, 2013 at 9:08 AM, Duncan Sands <baldrick at free.fr>
>> wrote:
>> >>>
>> >>> Author: baldrick
>> >>> Date: Tue Jul 23 11:07:59 2013
>> >>> New Revision: 186952
>> >>>
>> >>> URL: http://llvm.org/viewvc/llvm-project?rev=186952&view=rev
>> >>> Log:
>> >>> The debug info verifier requires a non-empty name here.  Pacify it.
>> >>
>> >>
>> >> If such debug info really doesn't need a name (I haven't looked at
>> the
>> >> code further to see which entity this code is for - a global
>> variable,
>> >> I guess) & we can/do support that (a test case would be good) we
>> >> should just fix the verification not to complain about such a valid
>> >> construct.
>> >
>> >
>> > thanks for taking an interest.
>> >
>> > It's like this: dragonegg produces debug info for this global variable
>> > because
>> > it produces debug info for all global variables, not because I think
>> it will
>> > enhance someone's debugging experience.  However it seems pretty
>> reasonable
>> > to
>> > me that it should be possible to produce natural debug info for any
>> global
>> > variable.  In this case natural means without a name, since this
>> variable is
>> > really anonymous.  In the original source code it is the number 77,
>> now sunk
>> > into a global constant so it can have its address taken.  Still, it
>> exists.
>> >
>> > So my view, taken from 1000 miles up and from the planet of those who
>> know
>> > nothing about debug info, is that nothing should be required to have a
>> name,
>> > because sometimes things just don't have names.  For example, I
>> already have
>> > to create artificial names for types because otherwise the debug
>> metadata is
>> > rejected, but I don't like it.
>> >
>> > If having no name means that the entity can't even be accessed in the
>> > debugger,
>> > then maybe that metadata should be dropped *as an optimization*.  But
>> not
>> > rejected as wrong.
>> >
>> > As I said, my view from a planet far far away from the land of those
>> that
>> > actually know something about debug info.
>>
>> Yep - sorry to make you repeat yourself. I did read your explanation
>> on the other thread in which Eric pointed out that nothing in the
>> debug info /requires/ a name, etc. I guess I'll wait for Eric to chime
>> back in here or there on where he thinks this should be dealt with.
>>
>> - David
>
> I'm not Eric, but it seems to me this sort of "variable" would be
> artificial, so maybe the verifier shouldn't insist on a name for
> things that are artificial?

*nod* I was going to go here as well. There are some artificial things
that do need names "this" parameters, but optional works for me.

Is it being marked as artificial? I mean, I don't necessarily
understand (even after looking at the code) why it's creating an
artificial global constant that it then reuses for debug information
either.

-eric

>
>>
>> >
>> > Ciao, Duncan.
>> >
>> >
>> >>
>> >>>
>> >>> Modified:
>> >>>      dragonegg/trunk/src/Debug.cpp
>> >>>
>> >>> Modified: dragonegg/trunk/src/Debug.cpp
>> >>> URL:
>> >>> http://llvm.org/viewvc/llvm-
>> project/dragonegg/trunk/src/Debug.cpp?rev=186952&r1=186951&r2=186952&vie
>> w=diff
>> >>>
>> >>>
>> ========================================================================
>> ======
>> >>> --- dragonegg/trunk/src/Debug.cpp (original)
>> >>> +++ dragonegg/trunk/src/Debug.cpp Tue Jul 23 11:07:59 2013
>> >>> @@ -411,6 +411,8 @@ void DebugInfo::EmitGlobalVariable(Globa
>> >>>     expanded_location Loc =
>> expand_location(DECL_SOURCE_LOCATION(decl));
>> >>>     DIType TyD = getOrCreateType(TREE_TYPE(decl));
>> >>>     StringRef DispName = GV->getName();
>> >>> +  if (DispName.empty())
>> >>> +    DispName = "__unknown__";
>> >>>     if (DECL_NAME(decl)) {
>> >>>       if (IDENTIFIER_POINTER(DECL_NAME(decl)))
>> >>>         DispName = IDENTIFIER_POINTER(DECL_NAME(decl));
>> >>>
>> >>>
>> >>> _______________________________________________
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>> >
>> >
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