llvm dev - Sep 2011 - [LLVMdev] DIBuilder - what's with the null compile units?

Sometime about two months ago, something changed in LLVM that broke my
frontend's ability to generate debug info. This was around the time that the
requirement to call DIBuilder::finalize() was added (and yes, I am calling
it.) Specifically, what I am seeing is an assertion failure in llc because
it can't find the compile unit for a subroutine.

I took a look at the code in DIBuilder.cpp, and I see that indeed it is
setting the compile unit to null for all of the various descriptors being
created. I assume that the intent is that these references would be filled
in later - but apparently this is not happening in my case. Any idea what
could be wrong?

-- 
-- Talin
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20110923/7dd98c1c/attachment.html>

On Sep 23, 2011, at 12:39 PM, Talin wrote:
> Sometime about two months ago, something changed in LLVM that broke my
frontend's ability to generate debug info. This was around the time that the
requirement to call DIBuilder::finalize() was added (and yes, I am calling it.)
Specifically, what I am seeing is an assertion failure in llc because it
can't find the compile unit for a subroutine.
> 
> I took a look at the code in DIBuilder.cpp, and I see that indeed it is
setting the compile unit to null for all of the various descriptors being
created. I assume that the intent is that these references would be filled in
later - but apparently this is not happening in my case.
They are not needed any more. During DIBuilder::finalize() the CompileUnit
itself collects all required info, which is good enough for CodeGen DwarfWriter.
The reason we inverted this graph is because it lets llvm linker unify mdnodes
during LTO.
> Any idea what could be wrong?
> 
> -- 
> -- Talin
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

On Sep 23, 2011, at 12:39 PM, Talin wrote:
> Sometime about two months ago, something changed in LLVM that broke my
frontend's ability to generate debug info. This was around the time that the
requirement to call DIBuilder::finalize() was added (and yes, I am calling it.)
Specifically, what I am seeing is an assertion failure in llc because it
can't find the compile unit for a subroutine.
I forgot to say earlier, that's a bug. Please file a PR with a test case.
-
Devang
> 
> I took a look at the code in DIBuilder.cpp, and I see that indeed it is
setting the compile unit to null for all of the various descriptors being
created. I assume that the intent is that these references would be filled in
later - but apparently this is not happening in my case. Any idea what could be
wrong?
> 
> -- 
> -- Talin
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

Hi,

Thanks for bringing this up, I'm just about to investigate an identical case
which has broken our front-end. Both ours and clang generate subroutineinfo with
null compilationunits, but ours asserts and clang's doesn't.

I'll take a look at this on Monday, if it is a bug in LLVM.

Cheers,

James

-----Original Message-----
From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On
Behalf Of Devang Patel
Sent: 23 September 2011 21:06
To: Talin
Cc: LLVM Developers Mailing List
Subject: Re: [LLVMdev] DIBuilder - what's with the null compile units?


On Sep 23, 2011, at 12:39 PM, Talin wrote:
> Sometime about two months ago, something changed in LLVM that broke my
frontend's ability to generate debug info. This was around the time that the
requirement to call DIBuilder::finalize() was added (and yes, I am calling it.)
Specifically, what I am seeing is an assertion failure in llc because it
can't find the compile unit for a subroutine.
I forgot to say earlier, that's a bug. Please file a PR with a test case.
-
Devang
>
> I took a look at the code in DIBuilder.cpp, and I see that indeed it is
setting the compile unit to null for all of the various descriptors being
created. I assume that the intent is that these references would be filled in
later - but apparently this is not happening in my case. Any idea what could be
wrong?
>
> --
> -- Talin
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
_______________________________________________
LLVM Developers mailing list
LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev


-- IMPORTANT NOTICE: The contents of this email and any attachments are
confidential and may also be privileged. If you are not the intended recipient,
please notify the sender immediately and do not disclose the contents to any
other person, use it for any purpose, or store or copy the information in any
medium.  Thank you.