[cfe-dev] Clang compiling needs help

Mon Mar 20 13:12:18 PDT 2017

Hi Michelle, Alon,

I'm seeing two problems. The first is that somehow a cpic object is being pulled into the
link, but I'm not seeing where. I was suspecting crtbegin.o is at fault as none of the library
files are marked cpic, but I'm unsure that it's that object now.

The second problem (which is causing the link to fail altogether) is that the linker is
rejecting the merge of the objects produced by clang and the portions of libgcc.a. There's
a number of possible reasons for this.

It could be rejecting the link because the clang produced objects contains gnu attributes
it doesn't understand or are incompatible with the ones in libgcc.a.

A second possible reason is the supplied linker only permits xcpu objects to be linked
together, i.e. you can't link mips32r2 objects with xcpu objects.

If the xcpu is really a mips1 chip with the usual mips1 structural hazards, clang+llvm can't
target it currently, as it doesn't deal with the mips1 hazards.

Thanks,
Simon

________________________________________
From: Michelle Gu (micgu) [mgu at nds.com]
Sent: 16 March 2017 09:15
To: Simon Dardis; Alon Shaltiel (ashaltie)
Cc: cfe-dev at lists.llvm.org
Subject: RE: Clang compiling needs help

Hi Simon,

Attached is the log with --verbose.

BR,
Michelle

-----Original Message-----
From: Michelle Gu (micgu)
Sent: 2017年3月16日 14:07
To: 'Simon Dardis' <Simon.Dardis at imgtec.com>; Alon Shaltiel (ashaltie) <ashaltie at cisco.com>
Cc: cfe-dev at lists.llvm.org
Subject: RE: Clang compiling needs help

Hi Simon,

Let me explain what I did first.
I used clang to compile a lib.
Then I move this lib to another environment which is not clang.
In that environment, I linked the lib generated in clang with other object to get a final object.
The final object is running on mips platform.

I met the issue during getting the final object.

-v in the another environment is just for version.
The output is as below. But I'm afraid this is not what you need.

OTAServer at OTAServer-VM201 /cygdrive/d/RDA/Projects/QW300/soft
$ mips-elf-ld -v
GNU ld (GNU Binutils) 2.20 (Coolsand Tech v.4)

BR,
Michelle

-----Original Message-----
From: Simon Dardis [mailto:Simon.Dardis at imgtec.com]
Sent: 2017年3月7日 19:13
To: Michelle Gu (micgu) <mgu at nds.com>; Alon Shaltiel (ashaltie) <ashaltie at cisco.com>
Cc: cfe-dev at lists.llvm.org
Subject: RE: Clang compiling needs help

Hi,

Those libraries and built objects look correct for noabi calls objects. I think the issue is that clang is invoking the linker with the dynamic crt objects instead of the static crt objects. Could you check by running the final link with -v in clang and see what directories it points the linker to for the crt objects?

Thanks,
Simon

> -----Original Message-----
> From: Michelle Gu (micgu) [mailto:mgu at nds.com]
> Sent: 06 March 2017 01:23
> To: Simon Dardis; Alon Shaltiel (ashaltie)
> Cc: cfe-dev at lists.llvm.org
> Subject: RE: Clang compiling needs help
>
> Hi Simon,
>
> Thank you for your feedback.
> Attached are the output according to what you said.
> clang.txt is the log of the file I built, while linked.txt is the log
> of lib I want to link with.
>
> BR,
> Michelle
>
> -----Original Message-----
> From: Simon Dardis [mailto:Simon.Dardis at imgtec.com]
> Sent: 2017年3月2日 20:37
> To: Alon Shaltiel (ashaltie) <ashaltie at cisco.com>; Michelle Gu (micgu)
> <mgu at nds.com>
> Cc: cfe-dev at lists.llvm.org
> Subject: RE: Clang compiling needs help
>
> Sorry about the delay in responding.
>
> Can you run 'readelf -h' over the files you've built and the libraries
> you're linking against and report back?
>
> You're looking for which files have 'cpic' in the Flags section of the
> ELF header.
>
> Thanks,
> Simon
>
> > -----Original Message-----
> > From: Alon Shaltiel (ashaltie) [mailto:ashaltie at cisco.com]
> > Sent: 02 March 2017 12:32
> > To: Michelle Gu (micgu); Simon Dardis
> > Cc: cfe-dev at lists.llvm.org
> > Subject: RE: Clang compiling needs help
> >
> > Can anyone please help with this?
> > The -mno-abicalls flag seems to still be problematic - even when
> > using the live svn build
> >
> > -----Original Message-----
> > From: Michelle Gu (micgu)
> > Sent: Wednesday, February 22, 2017 10:25 AM
> > To: Simon Dardis
> > Cc: Alon Shaltiel (ashaltie); cfe-dev at lists.llvm.org
> > Subject: RE: Clang compiling needs help
> >
> > Hi Simon,
> >
> > Thank you for your feedback!
> >
> > I checkout the live svn repository and build that
> > (http://www.llvm.org/docs/GettingStarted.html).
> >
> > Then use the option as below to get my object.
> >
> > ARCH_OPTS=-target mipsel
> > CFLAGS=-c -fno-pic -mno-abicalls -integrated-as
> >
> > But when linked to the mips object, the error code was still there.
> > Seems nothing changed.
> >
> > gcc.a(_ucmpdi2.o): warning: linking abicalls files with non-abicalls
> > files
> > mips-elf-ld: /cygdrive/d/RDA/Projects/QW300/soft/env/lib/gcc/mips-
> > elf/4.4.2//lib
> > gcc.a(_clzsi2.o): warning: linking abicalls files with non-abicalls
> > files
> > mips-elf-ld: /cygdrive/d/RDA/Projects/QW300/soft/env/lib/gcc/mips-
> > elf/4.4.2//lib
> > gcc.a(_fixunsdfsi.o): warning: linking abicalls files with
> > non-abicalls files
> > mips-elf-ld: /cygdrive/d/RDA/Projects/QW300/soft/env/lib/gcc/mips-
> > elf/4.4.2//lib
> > gcc.a(_pack_df.o): warning: linking abicalls files with non-abicalls
> > files
> > mips-elf-ld: /cygdrive/d/RDA/Projects/QW300/soft/env/lib/gcc/mips-
> > elf/4.4.2//lib
> > gcc.a(_unpack_df.o): warning: linking abicalls files with
> > non-abicalls files
> > mips-elf-ld: /cygdrive/d/RDA/Projects/QW300/soft/env/lib/gcc/mips-
> > elf/4.4.2//lib
> > gcc.a(_fpcmp_parts_df.o): warning: linking abicalls files with
> > non-abicalls file s
> > mips-elf-ld: /cygdrive/d/RDA/Projects/QW300/soft/env/lib/gcc/mips-
> > elf/4.4.2//lib
> > gcc.a(_ge_df.o): warning: linking abicalls files with non-abicalls
> > files
> > mips-elf-ld: /cygdrive/d/RDA/Projects/QW300/soft/env/lib/gcc/mips-
> > elf/4.4.2//lib
> > gcc.a(_df_to_si.o): warning: linking abicalls files with
> > non-abicalls files
> > make[2]: ***
> >
> [/cygdrive/d/RDA/Projects/QW300/soft/build/8851m_dbs_rdamodem_qj/_
> > d
> > efault_/8809/8851m_dbs_rdamodem_qj_debug_bin.elf] Error 1
> > make[1]: ***
> >
> [/cygdrive/d/RDA/Projects/QW300/soft/build/8851m_dbs_rdamodem_qj/_
> > d
> > efault_/8809/8851m_dbs_rdamodem_qj_debug_bin.srec] Error 2
> > make: *** [lod] Error 2
> >
> > Any other suggestion.
> >
> > BR,
> > Michelle
> >
> > -----Original Message-----
> > From: Simon Dardis [mailto:Simon.Dardis at imgtec.com]
> > Sent: 2017年2月10日 22:21
> > To: Michelle Gu (micgu) <mgu at nds.com>
> > Cc: Alon Shaltiel (ashaltie) <ashaltie at cisco.com>
> > Subject: RE: Clang compiling needs help
> >
> > Hi,
> >
> > My apologies, I spoke too soon. I'd forgotten that I also patched
> > clang recently to invoke the assembler correctly when -mno-abicalls
> > is passed to clang. Existing releases of clang will always pass
> > -call_nonpic to an external MIPS assembler. You could checkout the
> > live svn repository and build that
> > (http://www.llvm.org/docs/GettingStarted.html,
> > you'll need both llvm and clang) and use it to compile for MIPS. In
> > that case, I'd recommend using the integrated assembler (which is on
> > by default for MIPS32).
> >
> > Apologies again,
> > Simon
> >
> > > -----Original Message-----
> > > From: cfe-dev [mailto:cfe-dev-bounces at lists.llvm.org] On Behalf Of
> > > Simon Dardis via cfe-dev
> > > Sent: 10 February 2017 13:45
> > > To: Michelle Gu (micgu); cfe-dev at lists.llvm.org
> > > Cc: Alon Shaltiel (ashaltie)
> > > Subject: Re: [cfe-dev] Clang compiling needs help
> > >
> > > Hi,
> > >
> > > You need to use 'fno-pic -mno-abicalls -fno-integrated-as' to get
> > > the output you're looking for I believe. It does require the use
> > > of the GNU assembler, which may require specifying the sysroot of
> > > your gcc installation so clang finds the assembler and/or making a
> > > symlink
> 'mipsel-as'
> > to your mips-elf-as.
> > >
> > > Hopefully that should work around the warning. I don't have any
> > > other suggestions with the output you've posted.
> > >
> > > -mno-abicalls with -fintegrated-as should be properly supported in
> > > the next release after 4.0.
> > >
> > > Thanks,
> > > Simon
> > > ________________________________________
> > > From: Michelle Gu (micgu) [mgu at nds.com]
> > > Sent: 10 February 2017 02:07
> > > To: Simon Dardis; cfe-dev at lists.llvm.org
> > > Cc: Alon Shaltiel (ashaltie)
> > > Subject: RE: Clang compiling needs help
> > >
> > > Hi Simon,
> > >
> > > Thank you for your feedback!
> > >
> > > First, I delete '-fno-pic -mabicalls' options and rerun the
> > > compiling, the error result is same as before. I doubt if these
> > > options
> work or not.
> > > Second, when I tried to link my lib with other projects, I can see
> > > compile option ' WITHOUT_WERROR=1' during compiling. I think that
> > > means it's not the problem of warnings became errors.
> > >
> > > Do you have any other suggestion?
> > >
> > > BR,
> > > Michelle
> > >
> > > -----Original Message-----
> > > From: Simon Dardis [mailto:Simon.Dardis at imgtec.com]
> > > Sent: 2017年2月7日 22:04
> > > To: Michelle Gu (micgu) <mgu at nds.com>; cfe-dev at lists.llvm.org
> > > Cc: Alon Shaltiel (ashaltie) <ashaltie at cisco.com>
> > > Subject: RE: Clang compiling needs help
> > >
> > > The "warning: linking abicalls files with non-abicalls files"
> > > warning is almost certainly arising from a long standing LLVM bug
> > > where all files produced from the integrated assembler for MIPS
> > > were marked as being abicalls files. It's fixed on ToT.
> > >
> > > In theory the produced binary should be fine, as the error is
> > > occurring from incorrect ELF header flags. The error from 'make'
> > > may be due to treating warnings as errors.
> > >
> > > The CFLAGS you've specified appear to be inconsistent with your
> > > mips-elf target. "-fno-pic -mabicalls"
> > > produces position dependant code that can call position
> > > independent
> code.
> > > This would be for environments such as Linux/BSDs/etc. mips-elf I
> > > expect is a bare-metal environment, so -mabicalls would not be
> > > used for
> > that target.
> > >
> > > Thanks,
> > > Simon
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > cfe-dev mailing list
> > > cfe-dev at lists.llvm.org
> > > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev