llvm dev - Jan 2019 - 答复: 答复: How to add new arch for llvm-cov show?

Hi vedant,

  The program didn't pass the checking "OF->getArch() !=
Triple(Arch).getArch()" loadBinaryFormat in CoverageMappingReader.cpp and
returned an error. It's because "OF->getArch()" returned null
and "Triple(Arch).getArch()" returned XXXX(name of my arch).
  The returned value of  " OF->getArch()" is decided by "
EF.getHeader()->e_machine" but I found "e_machine" is defined
somewhere in MCAssembler(My compiler uses binutils as assembler) . Although I
make some hacks to pass this checking, I still get other errors. So my problem
is whether llvm-cov has to work with MCAssembler and is it possible to do it
with binutils?

Best,
Ruobin
> -----邮件原件-----
> 发件人: vsk at apple.com [mailto:vsk at apple.com]
> 发送时间: 2019年1月23日 1:24
> 收件人: xuruobin <xuruobin at huawei.com>
> 抄送: llvm-dev at lists.llvm.org; Yuchao (Michael)
> <michael.yuchao at huawei.com>
> 主题: Re: [llvm-dev] How to add new arch for llvm-cov show?
> 
> Hi Ruobin,
> 
> > On Jan 21, 2019, at 5:21 PM, xuruobin via llvm-dev <llvm-dev at
lists.llvm.org>
> wrote:
> >
> > Hi all,
> >
> > I'm trying to support llvm-cov for a new architecture and I have
successfully
> built compiler-rt for my arch. Following steps shown in
> https://clang.llvm.org/docs/SourceBasedCodeCoverage.html , I encountered
> an error for the last step(step of llvm-cov show).
> > The command line was (supposed my arch is XXXX)
> >
> > "llvm-cov show -arch=XXXX ./foo -instr-profile=foo.profdata"
> >
> > and the error was
> >
> > "Failed to load coverage: No object file for requested
architecture."
> >
> > I think I should add my arch information to somewhere(maybe an
llvm-cov
> support list?) but I don't know where to add these information. Can
> someone give me some suggestions?
> 
> You’ll need to teach libObject about this architecture. Specifically, the
> coverage reader checks that calling getArch() on a loaded ObjectFile
matches
> Triple(Arch).getArch() (see loadBinaryFormat in
> CoverageMappingReader.cpp).
> 
> best,
> vedant
> 
> 
> >
> > Best Regards,
> > Ruobin.
> > _______________________________________________
> > LLVM Developers mailing list
> > llvm-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

> On Jan 23, 2019, at 1:24 AM, xuruobin <xuruobin at huawei.com> wrote:
> 
> Hi vedant,
> 
>  The program didn't pass the checking "OF->getArch() !=
Triple(Arch).getArch()" loadBinaryFormat in CoverageMappingReader.cpp and
returned an error. It's because "OF->getArch()" returned null
and "Triple(Arch).getArch()" returned XXXX(name of my arch).
>  The returned value of  " OF->getArch()" is decided by "
EF.getHeader()->e_machine" but I found "e_machine" is defined
somewhere in MCAssembler
I haven’t double-checked, but I thought this definition came from
llvm/Support/ELF.h?

> (My compiler uses binutils as assembler) . Although I make some hacks to
pass this checking, I still get other errors. So my problem is whether llvm-cov
has to work with MCAssembler and is it possible to do it with binutils?
Coverage support should be / is largely compatible with binutils, but you may
have to watch out for this BFD bug:
https://clang.llvm.org/docs/SourceBasedCodeCoverage.html#drawbacks-and-limitations

What is the error you see?

vedant 
> 
> Best,
> Ruobin
> 
>> -----邮件原件-----
>> 发件人: vsk at apple.com [mailto:vsk at apple.com]
>> 发送时间: 2019年1月23日 1:24
>> 收件人: xuruobin <xuruobin at huawei.com>
>> 抄送: llvm-dev at lists.llvm.org; Yuchao (Michael)
>> <michael.yuchao at huawei.com>
>> 主题: Re: [llvm-dev] How to add new arch for llvm-cov show?
>> 
>> Hi Ruobin,
>> 
>>> On Jan 21, 2019, at 5:21 PM, xuruobin via llvm-dev <llvm-dev at
lists.llvm.org>
>> wrote:
>>> 
>>> Hi all,
>>> 
>>> I'm trying to support llvm-cov for a new architecture and I
have successfully
>> built compiler-rt for my arch. Following steps shown in
>> https://clang.llvm.org/docs/SourceBasedCodeCoverage.html , I
encountered
>> an error for the last step(step of llvm-cov show).
>>> The command line was (supposed my arch is XXXX)
>>> 
>>> "llvm-cov show -arch=XXXX ./foo
-instr-profile=foo.profdata"
>>> 
>>> and the error was
>>> 
>>> "Failed to load coverage: No object file for requested
architecture."
>>> 
>>> I think I should add my arch information to somewhere(maybe an
llvm-cov
>> support list?) but I don't know where to add these information. Can
>> someone give me some suggestions?
>> 
>> You’ll need to teach libObject about this architecture. Specifically,
the
>> coverage reader checks that calling getArch() on a loaded ObjectFile
matches
>> Triple(Arch).getArch() (see loadBinaryFormat in
>> CoverageMappingReader.cpp).
>> 
>> best,
>> vedant
>> 
>> 
>>> 
>>> Best Regards,
>>> Ruobin.
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> 
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Hi vedant,


1.       The definition is from llvm/Supprot/ELF.h. But this machine
information(e_machine) is given to compiler at lib/MC/ELFObjectWriter.cpp. I
greped the whole llvm project and found that e_machine was assigned at only two
files. One was lib/MC/ELFObjectWriter.cpp(there was an comment said
“e_machine=target”) and the other was tools/obj2yaml/elf2yaml.cpp(GDB stopped
only at the former one when using x86_64 llvm-cov so I thought it was MC provide
this e_machine information to compiler).

2.       New error was “Failed to load coverage: No coverage data found” since
the compiler cannot get NamesSection(at loadBinaryFormat in
CoverageMappingReader.cpp). I thought it was my ldscript problem because I put
__llvm_prf_names, __llvm_prf_cnts, __llvm_prf_data and __llvm_prf_vnds inside
.rodata section. Compiler checked .rodata but not things inside .rodata. What’s
the right position to put these 4 __llvm_prf_* sections?

Best,
Ruobin.

发件人: vsk at apple.com [mailto:vsk at apple.com] 代表 Vedant Kumar
发送时间: 2019年1月24日 0:12
收件人: xuruobin <xuruobin at huawei.com>
抄送: vsk at apple.com; llvm-dev at lists.llvm.org; Yuchao (Michael)
<michael.yuchao at huawei.com>
主题: Re: 答复: [llvm-dev] How to add new arch for llvm-cov show?


On Jan 23, 2019, at 1:24 AM, xuruobin <xuruobin at
huawei.com<mailto:xuruobin at huawei.com>> wrote:
Hi vedant,

 The program didn't pass the checking "OF->getArch() !=
Triple(Arch).getArch()" loadBinaryFormat in CoverageMappingReader.cpp and
returned an error. It's because "OF->getArch()" returned null
and "Triple(Arch).getArch()" returned XXXX(name of my arch).
 The returned value of  " OF->getArch()" is decided by "
EF.getHeader()->e_machine" but I found "e_machine" is defined
somewhere in MCAssembler

I haven’t double-checked, but I thought this definition came from
llvm/Support/ELF.h?



(My compiler uses binutils as assembler) . Although I make some hacks to pass
this checking, I still get other errors. So my problem is whether llvm-cov has
to work with MCAssembler and is it possible to do it with binutils?

Coverage support should be / is largely compatible with binutils, but you may
have to watch out for this BFD bug:
https://clang.llvm.org/docs/SourceBasedCodeCoverage.html#drawbacks-and-limitations

What is the error you see?

vedant



Best,
Ruobin


-----邮件原件-----
发件人: vsk at apple.com<mailto:vsk at apple.com> [mailto:vsk at apple.com]
发送时间: 2019年1月23日 1:24
收件人: xuruobin <xuruobin at huawei.com<mailto:xuruobin at
huawei.com>>
抄送: llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>; Yuchao
(Michael)
<michael.yuchao at huawei.com<mailto:michael.yuchao at huawei.com>>
主题: Re: [llvm-dev] How to add new arch for llvm-cov show?

Hi Ruobin,

On Jan 21, 2019, at 5:21 PM, xuruobin via llvm-dev <llvm-dev at
lists.llvm.org<mailto:llvm-dev at lists.llvm.org>>
wrote:

Hi all,

I'm trying to support llvm-cov for a new architecture and I have
successfully
built compiler-rt for my arch. Following steps shown in
https://clang.llvm.org/docs/SourceBasedCodeCoverage.html , I encountered
an error for the last step(step of llvm-cov show).
The command line was (supposed my arch is XXXX)

"llvm-cov show -arch=XXXX ./foo -instr-profile=foo.profdata"

and the error was

"Failed to load coverage: No object file for requested architecture."

I think I should add my arch information to somewhere(maybe an llvm-cov
support list?) but I don't know where to add these information. Can
someone give me some suggestions?

You’ll need to teach libObject about this architecture. Specifically, the
coverage reader checks that calling getArch() on a loaded ObjectFile matches
Triple(Arch).getArch() (see loadBinaryFormat in
CoverageMappingReader.cpp).

best,
vedant



Best Regards,
Ruobin.
_______________________________________________
LLVM Developers mailing list
llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

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Hi vedant,

I also used command “ld –verbose” to check x86_64 ldscript and found no
definition of __llvm_prf_* but if successfully passed. Why?

Best,
Ruobin.

发件人: xuruobin
发送时间: 2019年1月24日 15:36
收件人: 'Vedant Kumar' <vedant_kumar at apple.com>
抄送: vsk at apple.com; llvm-dev at lists.llvm.org; Yuchao (Michael)
<michael.yuchao at huawei.com>
主题: 答复: 答复: [llvm-dev] How to add new arch for llvm-cov show?

Hi vedant,


1.       The definition is from llvm/Supprot/ELF.h. But this machine
information(e_machine) is given to compiler at lib/MC/ELFObjectWriter.cpp. I
greped the whole llvm project and found that e_machine was assigned at only two
files. One was lib/MC/ELFObjectWriter.cpp(there was an comment said
“e_machine=target”) and the other was tools/obj2yaml/elf2yaml.cpp(GDB stopped
only at the former one when using x86_64 llvm-cov so I thought it was MC provide
this e_machine information to compiler).

2.       New error was “Failed to load coverage: No coverage data found” since
the compiler cannot get NamesSection(at loadBinaryFormat in
CoverageMappingReader.cpp). I thought it was my ldscript problem because I put
__llvm_prf_names, __llvm_prf_cnts, __llvm_prf_data and __llvm_prf_vnds inside
.rodata section. Compiler checked .rodata but not things inside .rodata. What’s
the right position to put these 4 __llvm_prf_* sections?

Best,
Ruobin.

发件人: vsk at apple.com<mailto:vsk at apple.com> [mailto:vsk at apple.com]
代表 Vedant Kumar
发送时间: 2019年1月24日 0:12
收件人: xuruobin <xuruobin at huawei.com<mailto:xuruobin at
huawei.com>>
抄送: vsk at apple.com<mailto:vsk at apple.com>; llvm-dev at
lists.llvm.org<mailto:llvm-dev at lists.llvm.org>; Yuchao (Michael)
<michael.yuchao at huawei.com<mailto:michael.yuchao at huawei.com>>
主题: Re: 答复: [llvm-dev] How to add new arch for llvm-cov show?


On Jan 23, 2019, at 1:24 AM, xuruobin <xuruobin at
huawei.com<mailto:xuruobin at huawei.com>> wrote:
Hi vedant,

 The program didn't pass the checking "OF->getArch() !=
Triple(Arch).getArch()" loadBinaryFormat in CoverageMappingReader.cpp and
returned an error. It's because "OF->getArch()" returned null
and "Triple(Arch).getArch()" returned XXXX(name of my arch).
 The returned value of  " OF->getArch()" is decided by "
EF.getHeader()->e_machine" but I found "e_machine" is defined
somewhere in MCAssembler

I haven’t double-checked, but I thought this definition came from
llvm/Support/ELF.h?


(My compiler uses binutils as assembler) . Although I make some hacks to pass
this checking, I still get other errors. So my problem is whether llvm-cov has
to work with MCAssembler and is it possible to do it with binutils?

Coverage support should be / is largely compatible with binutils, but you may
have to watch out for this BFD bug:
https://clang.llvm.org/docs/SourceBasedCodeCoverage.html#drawbacks-and-limitations

What is the error you see?

vedant


Best,
Ruobin

-----邮件原件-----
发件人: vsk at apple.com<mailto:vsk at apple.com> [mailto:vsk at apple.com]
发送时间: 2019年1月23日 1:24
收件人: xuruobin <xuruobin at huawei.com<mailto:xuruobin at
huawei.com>>
抄送: llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>; Yuchao
(Michael)
<michael.yuchao at huawei.com<mailto:michael.yuchao at huawei.com>>
主题: Re: [llvm-dev] How to add new arch for llvm-cov show?

Hi Ruobin,

On Jan 21, 2019, at 5:21 PM, xuruobin via llvm-dev <llvm-dev at
lists.llvm.org<mailto:llvm-dev at lists.llvm.org>>
wrote:

Hi all,

I'm trying to support llvm-cov for a new architecture and I have
successfully
built compiler-rt for my arch. Following steps shown in
https://clang.llvm.org/docs/SourceBasedCodeCoverage.html , I encountered
an error for the last step(step of llvm-cov show).
The command line was (supposed my arch is XXXX)

"llvm-cov show -arch=XXXX ./foo -instr-profile=foo.profdata"

and the error was

"Failed to load coverage: No object file for requested architecture."

I think I should add my arch information to somewhere(maybe an llvm-cov
support list?) but I don't know where to add these information. Can
someone give me some suggestions?

You’ll need to teach libObject about this architecture. Specifically, the
coverage reader checks that calling getArch() on a loaded ObjectFile matches
Triple(Arch).getArch() (see loadBinaryFormat in
CoverageMappingReader.cpp).

best,
vedant



Best Regards,
Ruobin.
_______________________________________________
LLVM Developers mailing list
llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

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