llvm dev - Oct 2016 - ThinLTO: module-scope inline assembly blocks

With `save-temps` as plugin option, I get extra files for the MAIN module
(called `a.o`): `a.o.opt.bc` and `a.thinlto.bc`.
The `a.thinlto.bc` file contains nothing, only `source_filename = ...` .
The `a.o.opt.bc` (this looks like the result after ThinLTO importing and
optimization) contains the assembly block that it should not have:
```
module asm "\09.text"
module asm "\09.globl\09foo"
module asm "\09.align\0916, 0x90"
module asm "\09.type\09foo, at function"
module asm "foo:"
module asm "\09movq %rdi, %rax"
module asm "\09rorw $8, %ax"
module asm "\09ret "
module asm "\09.size\09foo, .-foo"
module asm ""
```
The asm is the same as in the other module (where it _should_ be defined),
and the linkage has not been changed.

Thanks for the help,
  Johan


On Mon, Oct 3, 2016 at 4:45 PM, Teresa Johnson <tejohnson at google.com>
wrote:
> Oh sorry, misunderstood and thought you were implementing in a new linker.
> For gold you can pass -Wl,-plugin-opt,save-temps and look at the bitcode
> after each phase of ThinLTO, e.g. I think the files will have .3.import.bc
> extensions.
>
> Teresa
>
> On Mon, Oct 3, 2016 at 7:42 AM, Johan Engelen <jbc.engelen at
gmail.com>
> wrote:
>
>> On Mon, Oct 3, 2016 at 4:27 PM, Teresa Johnson <tejohnson at
google.com>
>> wrote:
>>
>>>
>>>
>>> On Mon, Oct 3, 2016 at 6:53 AM, Johan Engelen via llvm-dev <
>>> llvm-dev at lists.llvm.org> wrote:
>>>
>>>> Hi all,
>>>>   I am trying to add ThinLTO to the LDC compiler. It seems to
work well
>>>> on Mac (XCode 8) and Ubuntu (ld.gold + LLVMgold plugin).
>>>> However, I am running into trouble with module-scope inline
assembly
>>>> blocks.
>>>>
>>>
>>> Are you adding the support using the new LTO API or using the
libLTO C
>>> interfaces?
>>>
>>
>> Perhaps I don't fully understand, but I think the answer is:
neither :)
>> What I do is output the module as bitcode with the module summary index
>> added (`llvm::WriteBitcodeToFile`, summary index created with
>> `llvm::ModuleSummaryIndexBuilder`). This is then passed to the system
>> linker. The problems arise with ld.gold + LLVMgold plugin. I am using
LLVM
>> 3.9.0.
>>
>>
>
>
> --
> Teresa Johnson |  Software Engineer |  tejohnson at google.com |
> 408-460-2413
>
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On Mon, Oct 3, 2016, 8:08 AM Johan Engelen <jbc.engelen at gmail.com>
wrote:
> With `save-temps` as plugin option, I get extra files for the MAIN module
> (called `a.o`): `a.o.opt.bc` and `a.thinlto.bc`.
>
What revision is your gold plugin built from? I would expect more temp
files.

> The `a.thinlto.bc` file contains nothing, only `source_filename = ...` .
>
This is a dump of the combined index. llvm-dis won't show that, so
that's
not unexpected.

The `a.o.opt.bc` (this looks like the result after ThinLTO importing
and
> optimization) contains the assembly block that it should not have:
> ```
> module asm "\09.text"
> module asm "\09.globl\09foo"
> module asm "\09.align\0916, 0x90"
> module asm "\09.type\09foo, at function"
> module asm "foo:"
> module asm "\09movq %rdi, %rax"
> module asm "\09rorw $8, %ax"
> module asm "\09ret "
> module asm "\09.size\09foo, .-foo"
> module asm ""
> ```
> The asm is the same as in the other module (where it _should_ be defined),
> and the linkage has not been changed.
>
Will try to reproduce later this morning when I'm back in front of my
computer.

Teresa

> Thanks for the help,
>   Johan
>
>
> On Mon, Oct 3, 2016 at 4:45 PM, Teresa Johnson <tejohnson at
google.com>
> wrote:
>
> Oh sorry, misunderstood and thought you were implementing in a new linker.
> For gold you can pass -Wl,-plugin-opt,save-temps and look at the bitcode
> after each phase of ThinLTO, e.g. I think the files will have .3.import.bc
> extensions.
>
> Teresa
>
> On Mon, Oct 3, 2016 at 7:42 AM, Johan Engelen <jbc.engelen at
gmail.com>
> wrote:
>
> On Mon, Oct 3, 2016 at 4:27 PM, Teresa Johnson <tejohnson at
google.com>
> wrote:
>
>
>
> On Mon, Oct 3, 2016 at 6:53 AM, Johan Engelen via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
> Hi all,
>   I am trying to add ThinLTO to the LDC compiler. It seems to work well on
> Mac (XCode 8) and Ubuntu (ld.gold + LLVMgold plugin).
> However, I am running into trouble with module-scope inline assembly
> blocks.
>
>
> Are you adding the support using the new LTO API or using the libLTO C
> interfaces?
>
>
> Perhaps I don't fully understand, but I think the answer is: neither :)
> What I do is output the module as bitcode with the module summary index
> added (`llvm::WriteBitcodeToFile`, summary index created with
> `llvm::ModuleSummaryIndexBuilder`). This is then passed to the system
> linker. The problems arise with ld.gold + LLVMgold plugin. I am using LLVM
> 3.9.0.
>
>
>
>
> --
> Teresa Johnson |  Software Engineer |  tejohnson at google.com |
> 408-460-2413
>
>
>
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> On Oct 3, 2016, at 8:07 AM, Johan Engelen via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> With `save-temps` as plugin option, I get extra files for the MAIN module
(called `a.o`): `a.o.opt.bc` and `a.thinlto.bc`.
I’d expect as temps `a.thinlto.bc` for the index + one file per input. Also
there should be a number like: `a.o.4.opt.bc`

Can you attach the generated temp files?

Thanks,

— 
Mehdi


> The `a.thinlto.bc` file contains nothing, only `source_filename = ...` .
> The `a.o.opt.bc` (this looks like the result after ThinLTO importing and
optimization) contains the assembly block that it should not have:
> ```
> module asm "\09.text"
> module asm "\09.globl\09foo"
> module asm "\09.align\0916, 0x90"
> module asm "\09.type\09foo, at function"
> module asm "foo:"
> module asm "\09movq %rdi, %rax"
> module asm "\09rorw $8, %ax"
> module asm "\09ret "
> module asm "\09.size\09foo, .-foo"
> module asm ""
> ```
> The asm is the same as in the other module (where it _should_ be defined),
and the linkage has not been changed.
> 
> Thanks for the help,
>   Johan
> 
> 
> On Mon, Oct 3, 2016 at 4:45 PM, Teresa Johnson <tejohnson at google.com
<mailto:tejohnson at google.com>> wrote:
> Oh sorry, misunderstood and thought you were implementing in a new linker.
For gold you can pass -Wl,-plugin-opt,save-temps and look at the bitcode after
each phase of ThinLTO, e.g. I think the files will have .3.import.bc extensions.
> 
> Teresa
> 
> On Mon, Oct 3, 2016 at 7:42 AM, Johan Engelen <jbc.engelen at gmail.com
<mailto:jbc.engelen at gmail.com>> wrote:
> On Mon, Oct 3, 2016 at 4:27 PM, Teresa Johnson <tejohnson at google.com
<mailto:tejohnson at google.com>> wrote:
> 
> 
> On Mon, Oct 3, 2016 at 6:53 AM, Johan Engelen via llvm-dev <llvm-dev at
lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
> Hi all,
>   I am trying to add ThinLTO to the LDC compiler. It seems to work well on
Mac (XCode 8) and Ubuntu (ld.gold + LLVMgold plugin).
> However, I am running into trouble with module-scope inline assembly
blocks.
> 
> Are you adding the support using the new LTO API or using the libLTO C
interfaces?
> 
> Perhaps I don't fully understand, but I think the answer is: neither :)
> What I do is output the module as bitcode with the module summary index
added (`llvm::WriteBitcodeToFile`, summary index created with
`llvm::ModuleSummaryIndexBuilder`). This is then passed to the system linker.
The problems arise with ld.gold + LLVMgold plugin. I am using LLVM 3.9.0.
> 
> 
> 
> 
> -- 
> Teresa Johnson |	 Software Engineer |	 tejohnson at google.com
<mailto:tejohnson at google.com> |	 408-460-2413 <tel:408-460-2413>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
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The plugin version (and LLVM) are LLVM 3.9.0 (the release source tarball).

I've attached the source files and the temporary files generated.
`a.o` is the "MAIN" module.
`b.o` is the "ASM" module.

The error I get is:
/usr/bin/ld: error: a.o.thinlto.o: multiple definition of 'foo'
/usr/bin/ld: b.o.thinlto.o: previous definition here

(the files depend on D runtime lib, so upon succes you should see missing
symbol errors :-)

Thanks,
  Johan



On Mon, Oct 3, 2016 at 6:17 PM, Mehdi Amini <mehdi.amini at apple.com>
wrote:
>
> On Oct 3, 2016, at 8:07 AM, Johan Engelen via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
> With `save-temps` as plugin option, I get extra files for the MAIN module
> (called `a.o`): `a.o.opt.bc` and `a.thinlto.bc`.
>
>
> I’d expect as temps `a.thinlto.bc` for the index + one file per input.
> Also there should be a number like: `a.o.4.opt.bc`
>
> Can you attach the generated temp files?
>
> Thanks,
>
> —
> Mehdi
>
>
>
> The `a.thinlto.bc` file contains nothing, only `source_filename = ...` .
> The `a.o.opt.bc` (this looks like the result after ThinLTO importing and
> optimization) contains the assembly block that it should not have:
> ```
> module asm "\09.text"
> module asm "\09.globl\09foo"
> module asm "\09.align\0916, 0x90"
> module asm "\09.type\09foo, at function"
> module asm "foo:"
> module asm "\09movq %rdi, %rax"
> module asm "\09rorw $8, %ax"
> module asm "\09ret "
> module asm "\09.size\09foo, .-foo"
> module asm ""
> ```
> The asm is the same as in the other module (where it _should_ be defined),
> and the linkage has not been changed.
>
> Thanks for the help,
>   Johan
>
>
> On Mon, Oct 3, 2016 at 4:45 PM, Teresa Johnson <tejohnson at
google.com>
> wrote:
>
>> Oh sorry, misunderstood and thought you were implementing in a new
>> linker. For gold you can pass -Wl,-plugin-opt,save-temps and look at
the
>> bitcode after each phase of ThinLTO, e.g. I think the files will have
>> .3.import.bc extensions.
>>
>> Teresa
>>
>> On Mon, Oct 3, 2016 at 7:42 AM, Johan Engelen <jbc.engelen at
gmail.com>
>> wrote:
>>
>>> On Mon, Oct 3, 2016 at 4:27 PM, Teresa Johnson <tejohnson at
google.com>
>>> wrote:
>>>
>>>>
>>>>
>>>> On Mon, Oct 3, 2016 at 6:53 AM, Johan Engelen via llvm-dev <
>>>> llvm-dev at lists.llvm.org> wrote:
>>>>
>>>>> Hi all,
>>>>>   I am trying to add ThinLTO to the LDC compiler. It seems
to work
>>>>> well on Mac (XCode 8) and Ubuntu (ld.gold + LLVMgold
plugin).
>>>>> However, I am running into trouble with module-scope inline
assembly
>>>>> blocks.
>>>>>
>>>>
>>>> Are you adding the support using the new LTO API or using the
libLTO C
>>>> interfaces?
>>>>
>>>
>>> Perhaps I don't fully understand, but I think the answer is:
neither :)
>>> What I do is output the module as bitcode with the module summary
index
>>> added (`llvm::WriteBitcodeToFile`, summary index created with
>>> `llvm::ModuleSummaryIndexBuilder`). This is then passed to the
system
>>> linker. The problems arise with ld.gold + LLVMgold plugin. I am
using LLVM
>>> 3.9.0.
>>>
>>>
>>
>>
>> --
>> Teresa Johnson |  Software Engineer |  tejohnson at google.com |
>> 408-460-2413
>>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
>
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