[cfe-dev] Cleanup on aisle DebugInfo enums

Fri Feb 5 15:42:06 PST 2016

Re-add cfe-dev so the email trail is (more) complete.
clang-tools-extra fiddled in r259949, the duplicate DebuggerKind enum removed in r259950.
--paulr

From: David Blaikie [mailto:dblaikie at gmail.com]
Sent: Friday, February 05, 2016 3:20 PM
To: Robinson, Paul
Cc: Eric Christopher; Benjamin Kramer
Subject: Re: [cfe-dev] Cleanup on aisle DebugInfo enums

Thanks for the cleanup!

On Fri, Feb 5, 2016 at 3:18 PM, Robinson, Paul <Paul_Robinson at playstation.sony.com<mailto:Paul_Robinson at playstation.sony.com>> wrote:
Oh cool, the clang-tools-extra problem is just two places in one file.  I remember it being more involved, but hey.
I'll push that, then eliminate the duplicate enum in Clang.
Thanks guys!
--paulr

From: cfe-dev [mailto:cfe-dev-bounces at lists.llvm.org<mailto:cfe-dev-bounces at lists.llvm.org>] On Behalf Of Robinson, Paul via cfe-dev
Sent: Friday, February 05, 2016 2:28 PM
To: Eric Christopher; David Blaikie
Cc: cfe-dev at lists.llvm.org<mailto:cfe-dev at lists.llvm.org>; Benjamin Kramer

Subject: Re: [cfe-dev] Cleanup on aisle DebugInfo enums

Well, moving DebugInfoKind to Basic seemed agreeable anyway, and that's done (r259935).
I'll re-investigate undoing the Clang version of the debugger-kind enum.
--paulr

From: Eric Christopher [mailto:echristo at gmail.com]
Sent: Friday, February 05, 2016 2:17 PM
To: David Blaikie; Robinson, Paul
Cc: Adrian Prantl; Benjamin Kramer; cfe-dev at lists.llvm.org<mailto:cfe-dev at lists.llvm.org>
Subject: Re: [cfe-dev] Cleanup on aisle DebugInfo enums

On Fri, Feb 5, 2016 at 2:11 PM David Blaikie <dblaikie at gmail.com<mailto:dblaikie at gmail.com>> wrote:
On Fri, Feb 5, 2016 at 11:30 AM, Robinson, Paul <Paul_Robinson at playstation.sony.com<mailto:Paul_Robinson at playstation.sony.com>> wrote:
what's the motivation not to use the LLVM versions of these enums

I originally implemented the Clang bits for debugger tuning using the LLVM enum (r256063).  However this caused build failures in clang-tools-extra (which I didn't have checked out locally) because having CodeGenOptions.h pull in the extra LLVM header caused confusion in some unqualified name references.
Rather than introduce the extra qualifiers in clang-tools-extra (I looked, it would have taken a bit to sort everything out) I undid the dependency on the LLVM headers and just replicated the enum in Clang.  The only place in Clang that still "really" needed the LLVM enum is BackendUtil.cpp (natch) and it is careful not to assume the two enums are defined the same way.

Still seems a bit subtle - are there reasons we should avoid using the LLVM enum apart from the unknown issue with clang-tools-extra? (if we generally keep these types/enums separate, that's OK - but don't want to propagate a workaround if we don't fully understand what we're working around)

We've kept a bunch of the target stuff separate, but I don't see any reason to not use the general dwarf enums. I think we should just fix the clang-tools-extra stuff.

-eric

This got committed in r256078.
However, I wasn't thorough enough about digging out the LLVM dependencies, and Driver is still using the LLVM enum.
If I'd gotten the Driver part right the first time around, Benny would've had to move both enums in his patch.

This Clang-versus-LLVM consideration applies only to the tuning enum, btw; LLVM doesn't have an analog of DebugInfoKind.
--paulr

From: David Blaikie [mailto:dblaikie at gmail.com<mailto:dblaikie at gmail.com>]
Sent: Friday, February 05, 2016 11:06 AM
To: Robinson, Paul; Adrian Prantl; Eric Christopher; Benjamin Kramer
Cc: cfe-dev at lists.llvm.org<mailto:cfe-dev at lists.llvm.org>
Subject: Re: [cfe-dev] Cleanup on aisle DebugInfo enums

Sounds plausible.

(just to check: what's the motivation not to use the LLVM versions of these enums if they match the desired semantics? (I imagine there are many good reasons not to use them, just figure it's worth writing down in this thread so it's clear for historic purposes))

On Fri, Feb 5, 2016 at 10:57 AM, Robinson, Paul via cfe-dev <cfe-dev at lists.llvm.org<mailto:cfe-dev at lists.llvm.org>> wrote:
In r259489, Benny Kramer moved the DebugInfoKind enum into its own
header, include/clang/Driver/DebugInfoKind.h. This was to prevent
Driver from pulling in headers from Frontend.  However, this leaves
the enum in kind of a weird place, I think Basic would be better (and
not re-introduce the problem Benny was solving).

Wondering why the tuning enum didn't cause the same problem, I found
that when I created the Clang enum, I didn't make Driver use it; it's
still using the LLVM version of the enum.  While this is not
technically wrong (you could rearrange the values and it would do no
harm) it's an inconsistency within Clang.

But, if I make Driver use the tuning enum from Clang's CodeGenOptions,
then we'll have the same problem that prompted r259489 in the first
place--Driver depending on Frontend. Rather than create Yet Another
Header, it would be convenient to put the tuning enum in the same
place as DebugInfoKind, as they are topically related and commonly
used in the same places.

I propose to do the following:

Patch #1 (totally mechanical)
- move DebugInfoKind.h from Driver to Basic
- rename it to DebugInfoOptions.h
This will take care of all the #include renaming in one go.

Patch #2 (basically mechanical)
- move the DebuggerKind enum from CodeGenOptions.h to DebugInfoOptions.h
- fix up Driver to use this enum instead of the LLVM equivalent.

Or I can do it all at once, the combined patch would still be
reasonable I think.

Sound okay?
--paulr

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