[LLVMdev] Nested functions

[S. Bharadwaj Yadavalli]

Hi Duncan,

Thanks for your reply.

I did try the method suggested by you. I got a foo.bc with -emit-llvm
switch. llc on foo.bc gets me the same assertion failure, as you pointed
out.

Then I ran bugpoint to generate bugpoint-reduced-simplified.bc and
bugpoint-reduced-function.bc. My previous experience is that if I compile
either if them, I would get the same failure as I did with foo.bc. That is
not the case. I get a different assertion failure when I compile either of
them with llc which is as follows:

llc: <llvm-src>/llvm/lib/CodeGen/AsmPrinter/DwarfWriter.cpp:2808: void
llvm::DwarfDebug::ConstructCompileUnits(): Assertion
`Root->hasLinkOnceLinkage() && Root->hasOneUse() && "Malformed compile unit
descriptor anchor type"' failed.

This makes it hard for me to easily create a test case and submit a bug
report.

Hence, I thought I should take this opportunity to delve deeper into LLVM
and look at this issue.

Any further nudges / help is highly appreciated!

Thanks,

Bharadwaj

On Wed, Mar 4, 2009 at 3:59 PM, Duncan Sands <baldrick at free.fr> wrote:

> Hi Bharadwaj,
>
> > I get the following error during compilation using the LLVM
> cross-compiler
> > (x86_64->arm).
> >
> > error: nested functions are disabled, use -fnested-functions to re-enable
>
> yes, nested functions are disabled by default in llvm-gcc (not sure why -
> maybe a historical hang over from the days when they were not supported?).
>
> > With -fnested-functions switch, I get the following error:
> >
> > <llvm-src-dir>/llvm/lib/Target/ARM/ARMISelLowering.cpp:1439: virtual
> > llvm::SDValue llvm::ARMTargetLowering::LowerOperation(llvm::SDValue,
> > llvm::SelectionDAG&): Assertion `0 && "Don't know how to custom lower
> > this!"' failed.
> > frobos/tests/hello.c:453: internal compiler error: Aborted
> > Please submit a full bug report,
> > with preprocessed source if appropriate.
> > See <URL:http://developer.apple.com/bugreporter> for instructions.
> >
> > I'd like to investigate this but am wondering if anyone has any
> > thoughts/suggestions in this area.
>
> I don't know anything about cross-compiling, but the usual way
> to debug this kind of thing is to re-run by hand the line that
> caused this assertion, but adding -emit-llvm to the command line.
> The output will then contain LLVM bitcode.  If you are lucky,
> then running llc on the bitcode will give the same assertion
> failure.  If so, then "bugpoint --run-llc the_bit_code" should
> automatically reduce a minimal testcase.
>
> Ciao,
>
> Duncan.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20090304/062f9e81/attachment.html>