[PATCH] Fix for LLVM debug build failure on Windows + MSVC2010SP1

[Manish Verma]

Hi Aaron,

> We have more than 65535 sections in a single object file?  That seems
> rather large to me; I wonder if that was intended behavior.
Good question! The source file doesn't look very big. I wonder what is
causing MSVC to generate these many sections in single object file.

> According to MSDN, /bigobj works as far back as VS 2005; do you see
> that it fails in practice?  If so, it's not a big deal, we really
> only
> care about 2010 and up at this point.
I don't think even today LLVM can be built with VC++ 2005. So, I guess
this shouldn't be a problem in practice. Plus, if and when, LLVM moves
to C++11, older MSVC wouldn't be supported anyway.

Manish

> -----Original Message-----
> From: aaron.ballman at gmail.com [mailto:aaron.ballman at gmail.com] On
> Behalf Of Aaron Ballman
> Sent: 07 June 2013 16:15
> To: Manish Verma
> Cc: llvm-commits
> Subject: Re: [PATCH] Fix for LLVM debug build failure on Windows +
> MSVC2010SP1
>
> We have more than 65535 sections in a single object file?  That seems
> rather large to me; I wonder if that was intended behavior.
>
> According to MSDN, /bigobj works as far back as VS 2005; do you see
> that it fails in practice?  If so, it's not a big deal, we really
> only
> care about 2010 and up at this point.
>
> ~Aaron
>
> On Fri, Jun 7, 2013 at 10:59 AM, Manish Verma <manish.verma at arm.com>
> wrote:
> > Hi,
> >
> > We have recently found that the debug builds on Windows are failing
> when
> > compiled with MSVC 2010SP1. The failure message generated is the
> following:
> >
> >
> f:\work\src\llvm\tools\clang\include\clang\astmatchers\astmatchersint
> ernal.h
> > (266): fatal error C1128: number of sections exceeded object file
> format
> > limit : compile with /bigobj
> > [F:\work\build\win_32-linkMT-x86_64\cl_16.00.40219.01-
> vs\dbg\llvm\tools\clan
> > g\lib\ASTMatchers\Dynamic\clangDynamicASTMatchers.vcxproj]
> >
> > A similar build failure is also reported today in
> > http://lists.cs.uiuc.edu/pipermail/cfe-dev/2013-June/030043.html.
> >
> > Please find attached a patch which fixes the build failure and adds
> /bigobj
> > option to CXX_FLAGS for debug builds.
> >
> > One of the downside of this patch is that the debug builds of LLVM
> can no
> > longer done using Visual Studio C++ 2005 or previous versions.
> Otherwise, I
> > couldn't find any other downside of using /bigobj option.
> >
> > Manish
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> >


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