[llvm-dev] LLD COFF not closing mmaps to input files?

[Rui Ueyama via llvm-dev]

lld::coff::LinkerDriver::link is not expected to return, so the patch
doesn't make sense unless you have a local patch to make it return, but I'm
fine with that change because it is harmless. Please go ahead.

On Sun, Oct 15, 2017 at 7:07 PM, Andrew Kelley <superjoe30 at gmail.com> wrote:

> Thanks Rui, your suggestion solved the problem perfectly.
>
> diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
> index 8bab1c11..0dabca6e 100644
> --- a/lld/COFF/Driver.cpp
> +++ b/lld/COFF/Driver.cpp
> @@ -61,6 +61,7 @@ bool link(ArrayRef<const char *> Args, raw_ostream
> &Diag) {
>        (ErrorOS == &llvm::errs() && Process::StandardErrHasColors());
>    Driver = make<LinkerDriver>();
>    Driver->link(Args);
> +  freeArena();
>    return !ErrorCount;
>  }
>
> Could we get this patch upstream?
>
> On Sun, Oct 15, 2017 at 9:59 PM, Rui Ueyama <ruiu at google.com> wrote:
>
>> I think you want to call freeArena() before returning from
>> lld::coff::link.
>>
>> On Sun, Oct 15, 2017 at 6:57 PM, Andrew Kelley via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> I believe this line is the culprit:
>>>
>>> COFF/Driver.cpp:102:
>>>   make<std::unique_ptr<MemoryBuffer>>(std::move(MB)); // take ownership
>>>
>>> Patch forthcoming.
>>>
>>>
>>> On Sun, Oct 15, 2017 at 9:45 PM, Andrew Kelley <superjoe30 at gmail.com>
>>> wrote:
>>>
>>>> I've got a patched LLD 5.0.0 like this:
>>>>
>>>> diff --git a/deps/lld/COFF/Driver.cpp b/deps/lld/COFF/Driver.cpp
>>>> index 854c3e69..8bab1c11 100644
>>>> --- a/deps/lld/COFF/Driver.cpp
>>>> +++ b/deps/lld/COFF/Driver.cpp
>>>> @@ -1030,7 +1030,7 @@ void LinkerDriver::link(ArrayRef<const char *>
>>>> ArgsArr) {
>>>>    if (!Args.hasArgNoClaim(OPT_INPUT)) {
>>>>      fixupExports();
>>>>      createImportLibrary(/*AsLib=*/true);
>>>> -    exit(0);
>>>> +    return;
>>>>    }
>>>>
>>>>    // Handle /delayload
>>>> @@ -1172,9 +1172,6 @@ void LinkerDriver::link(ArrayRef<const char *>
>>>> ArgsArr) {
>>>>
>>>>    // Write the result.
>>>>    writeResult(&Symtab);
>>>> -
>>>> -  // Call exit to avoid calling destructors.
>>>> -  exit(0);
>>>>  }
>>>>
>>>>  } // namespace coff
>>>>
>>>>
>>>> I'm getting this error from LLVM:
>>>> unable to write object file c:\msys64\home\andy\zig\zig-cache\compiler_rt.obj:
>>>> The requested operation cannot be performed on a file with a user-mapped
>>>> section open.
>>>>
>>>> The same process calls LLD with this .obj as  a linker input file, then
>>>> tries to write to the same .obj file later.
>>>>
>>>> I believe LLD is mmapping the .obj file and then not cleaning it up.
>>>>
>>>> Can I have some guidance as to where in the code I could discover this
>>>> and clean it up?
>>>>
>>>> Regards,
>>>> Andrew
>>>> http://ziglang.org/
>>>>
>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
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>>>
>>>
>>
>
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