[lld] r311056 - Remove a lock and use a std::unique_ptr instead.

[Rui Ueyama via llvm-commits]

Just noticed that Rafael already made a change. Thanks guys!

On Wed, Sep 6, 2017 at 5:11 PM, Rui Ueyama <ruiu at google.com> wrote:

> That's true -- I'll change the type so that UncompressedBuf is just a
> std::vector<uint8_t>.
>
> On Wed, Sep 6, 2017 at 3:08 PM, David Blaikie <dblaikie at gmail.com> wrote:
>
>> yeah, sounds good to me (well, unique_ptr<uint8_t[]>, I guess)
>>
>> On Wed, Sep 6, 2017 at 3:01 PM Rafael Avila de Espindola <
>> rafael.espindola at gmail.com> wrote:
>>
>>> Alternativelly it can also just be a std::unique_ptr<uint8_t>, no?
>>>
>>> Cheers,
>>> Rafael
>>>
>>> David Blaikie via llvm-commits <llvm-commits at lists.llvm.org> writes:
>>>
>>> > Is it really worth/necessary to indirect this vector through a
>>> unique_ptr?
>>> > Saves two words in the InputSection, I guess, in the common (not
>>> > compressed) case? (could save the other word too, if you used a
>>> separate
>>> > map to only store these things when needed)
>>> >
>>> > But maybe this is the sweet spot of convenience and memory usage. Just
>>> > curious/checking :)
>>> >
>>> > On Wed, Aug 16, 2017 at 5:28 PM Rui Ueyama via llvm-commits <
>>> > llvm-commits at lists.llvm.org> wrote:
>>> >
>>> >> Author: ruiu
>>> >> Date: Wed Aug 16 17:27:55 2017
>>> >> New Revision: 311056
>>> >>
>>> >> URL: http://llvm.org/viewvc/llvm-project?rev=311056&view=rev
>>> >> Log:
>>> >> Remove a lock and use a std::unique_ptr instead.
>>> >>
>>> >> We had a lock to guard BAlloc from being used concurrently, but that
>>> >> is not very easy to understand. This patch replaces it with a
>>> >> std::unique_ptr.
>>> >>
>>> >> Modified:
>>> >>     lld/trunk/ELF/InputSection.cpp
>>> >>     lld/trunk/ELF/InputSection.h
>>> >>
>>> >> Modified: lld/trunk/ELF/InputSection.cpp
>>> >> URL:
>>> >> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSecti
>>> on.cpp?rev=311056&r1=311055&r2=311056&view=diff
>>> >>
>>> >> ============================================================
>>> ==================
>>> >> --- lld/trunk/ELF/InputSection.cpp (original)
>>> >> +++ lld/trunk/ELF/InputSection.cpp Wed Aug 16 17:27:55 2017
>>> >> @@ -200,17 +200,12 @@ void InputSectionBase::uncompress() {
>>> >>                                                  Config->IsLE,
>>> >> Config->Is64));
>>> >>
>>> >>    size_t Size = Dec.getDecompressedSize();
>>> >> -  char *OutputBuf;
>>> >> -  {
>>> >> -    static std::mutex Mu;
>>> >> -    std::lock_guard<std::mutex> Lock(Mu);
>>> >> -    OutputBuf = BAlloc.Allocate<char>(Size);
>>> >> -  }
>>> >> -
>>> >> -  if (Error E = Dec.decompress({OutputBuf, Size}))
>>> >> +  UncompressBuf.reset(new std::vector<uint8_t>(Size));
>>> >> +  if (Error E = Dec.decompress({(char *)UncompressBuf->data(),
>>> Size}))
>>> >>      fatal(toString(this) +
>>> >>            ": decompress failed: " + llvm::toString(std::move(E)));
>>> >> -  this->Data = ArrayRef<uint8_t>((uint8_t *)OutputBuf, Size);
>>> >> +
>>> >> +  this->Data = *UncompressBuf;
>>> >>    this->Flags &= ~(uint64_t)SHF_COMPRESSED;
>>> >>  }
>>> >>
>>> >>
>>> >> Modified: lld/trunk/ELF/InputSection.h
>>> >> URL:
>>> >> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSecti
>>> on.h?rev=311056&r1=311055&r2=311056&view=diff
>>> >>
>>> >> ============================================================
>>> ==================
>>> >> --- lld/trunk/ELF/InputSection.h (original)
>>> >> +++ lld/trunk/ELF/InputSection.h Wed Aug 16 17:27:55 2017
>>> >> @@ -183,6 +183,11 @@ public:
>>> >>      assert(S % sizeof(T) == 0);
>>> >>      return llvm::makeArrayRef<T>((const T *)Data.data(), S /
>>> sizeof(T));
>>> >>    }
>>> >> +
>>> >> +private:
>>> >> +  // A pointer that owns uncompressed data if a section is
>>> compressed by
>>> >> zlib.
>>> >> +  // Since the feature is not used often, this is usually a nullptr.
>>> >> +  std::unique_ptr<std::vector<uint8_t>> UncompressBuf;
>>> >>  };
>>> >>
>>> >>  // SectionPiece represents a piece of splittable section contents.
>>> >>
>>> >>
>>> >> _______________________________________________
>>> >> llvm-commits mailing list
>>> >> llvm-commits at lists.llvm.org
>>> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>> >>
>>> > _______________________________________________
>>> > llvm-commits mailing list
>>> > llvm-commits at lists.llvm.org
>>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170906/76492c4e/attachment.html>