[lld] r302613 - [Core] Make parallel algorithms match C++ Parallelism TS.

Hans Wennborg via llvm-commits llvm-commits at lists.llvm.org
Wed May 10 09:34:05 PDT 2017


I think maybe we can just move the #ifdef a little so
detail::DefComparator is always defined. I'm trying that right now.

On Wed, May 10, 2017 at 9:29 AM, Zachary Turner <zturner at google.com> wrote:
> I will try a build with LLVM_ENABLE_THREADS=0 locally and see if I can repro
>
> On Wed, May 10, 2017 at 9:28 AM Hans Wennborg <hans at chromium.org> wrote:
>>
>> Oh, it's because of #if LLVM_ENABLE_THREADS
>>
>> On Wed, May 10, 2017 at 9:27 AM, Hans Wennborg <hans at chromium.org> wrote:
>> > This broke Chromium's lld builds, e.g.
>> >
>> > https://build.chromium.org/p/chromium.fyi/builders/ClangToTLinux/builds/8161
>> >
>> > I'm not sure why it's not a problem on the regular LLVM buildbots,
>> > though.
>> >
>> > On Tue, May 9, 2017 at 6:16 PM, Zachary Turner via llvm-commits
>> > <llvm-commits at lists.llvm.org> wrote:
>> >> Author: zturner
>> >> Date: Tue May  9 20:16:22 2017
>> >> New Revision: 302613
>> >>
>> >> URL: http://llvm.org/viewvc/llvm-project?rev=302613&view=rev
>> >> Log:
>> >> [Core] Make parallel algorithms match C++ Parallelism TS.
>> >>
>> >> Differential Revision: https://reviews.llvm.org/D33016
>> >>
>> >> Modified:
>> >>     lld/trunk/COFF/ICF.cpp
>> >>     lld/trunk/COFF/MapFile.cpp
>> >>     lld/trunk/COFF/Writer.cpp
>> >>     lld/trunk/ELF/Threads.h
>> >>     lld/trunk/include/lld/Core/Parallel.h
>> >>     lld/trunk/lib/ReaderWriter/MachO/LayoutPass.cpp
>> >>     lld/trunk/unittests/CoreTests/ParallelTest.cpp
>> >>
>> >> Modified: lld/trunk/COFF/ICF.cpp
>> >> URL:
>> >> http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/ICF.cpp?rev=302613&r1=302612&r2=302613&view=diff
>> >>
>> >> ==============================================================================
>> >> --- lld/trunk/COFF/ICF.cpp (original)
>> >> +++ lld/trunk/COFF/ICF.cpp Tue May  9 20:16:22 2017
>> >> @@ -192,7 +192,7 @@ void ICF::forEachClass(std::function<voi
>> >>    // Split sections into 256 shards and call Fn in parallel.
>> >>    size_t NumShards = 256;
>> >>    size_t Step = Chunks.size() / NumShards;
>> >> -  parallel_for(size_t(0), NumShards, [&](size_t I) {
>> >> +  for_each_n(parallel::par, size_t(0), NumShards, [&](size_t I) {
>> >>      forEachClassRange(I * Step, (I + 1) * Step, Fn);
>> >>    });
>> >>    forEachClassRange(Step * NumShards, Chunks.size(), Fn);
>> >>
>> >> Modified: lld/trunk/COFF/MapFile.cpp
>> >> URL:
>> >> http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/MapFile.cpp?rev=302613&r1=302612&r2=302613&view=diff
>> >>
>> >> ==============================================================================
>> >> --- lld/trunk/COFF/MapFile.cpp (original)
>> >> +++ lld/trunk/COFF/MapFile.cpp Tue May  9 20:16:22 2017
>> >> @@ -76,7 +76,7 @@ static SymbolMapTy getSectionSyms(ArrayR
>> >>  static DenseMap<DefinedRegular *, std::string>
>> >>  getSymbolStrings(ArrayRef<DefinedRegular *> Syms) {
>> >>    std::vector<std::string> Str(Syms.size());
>> >> -  parallel_for((size_t)0, Syms.size(), [&](size_t I) {
>> >> +  for_each_n(parallel::par, (size_t)0, Syms.size(), [&](size_t I) {
>> >>      raw_string_ostream OS(Str[I]);
>> >>      writeHeader(OS, Syms[I]->getRVA(), 0, 0);
>> >>      OS << indent(2) << toString(*Syms[I]);
>> >>
>> >> Modified: lld/trunk/COFF/Writer.cpp
>> >> URL:
>> >> http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Writer.cpp?rev=302613&r1=302612&r2=302613&view=diff
>> >>
>> >> ==============================================================================
>> >> --- lld/trunk/COFF/Writer.cpp (original)
>> >> +++ lld/trunk/COFF/Writer.cpp Tue May  9 20:16:22 2017
>> >> @@ -745,8 +745,8 @@ void Writer::writeSections() {
>> >>      // ADD instructions).
>> >>      if (Sec->getPermissions() & IMAGE_SCN_CNT_CODE)
>> >>        memset(SecBuf, 0xCC, Sec->getRawSize());
>> >> -    parallel_for_each(Sec->getChunks().begin(),
>> >> Sec->getChunks().end(),
>> >> -                      [&](Chunk *C) { C->writeTo(SecBuf); });
>> >> +    for_each(parallel::par, Sec->getChunks().begin(),
>> >> Sec->getChunks().end(),
>> >> +             [&](Chunk *C) { C->writeTo(SecBuf); });
>> >>    }
>> >>  }
>> >>
>> >> @@ -760,16 +760,14 @@ void Writer::sortExceptionTable() {
>> >>    uint8_t *End = Begin + Sec->getVirtualSize();
>> >>    if (Config->Machine == AMD64) {
>> >>      struct Entry { ulittle32_t Begin, End, Unwind; };
>> >> -    parallel_sort(
>> >> -        (Entry *)Begin, (Entry *)End,
>> >> -        [](const Entry &A, const Entry &B) { return A.Begin < B.Begin;
>> >> });
>> >> +    sort(parallel::par, (Entry *)Begin, (Entry *)End,
>> >> +         [](const Entry &A, const Entry &B) { return A.Begin <
>> >> B.Begin; });
>> >>      return;
>> >>    }
>> >>    if (Config->Machine == ARMNT) {
>> >>      struct Entry { ulittle32_t Begin, Unwind; };
>> >> -    parallel_sort(
>> >> -        (Entry *)Begin, (Entry *)End,
>> >> -        [](const Entry &A, const Entry &B) { return A.Begin < B.Begin;
>> >> });
>> >> +    sort(parallel::par, (Entry *)Begin, (Entry *)End,
>> >> +         [](const Entry &A, const Entry &B) { return A.Begin <
>> >> B.Begin; });
>> >>      return;
>> >>    }
>> >>    errs() << "warning: don't know how to handle .pdata.\n";
>> >>
>> >> Modified: lld/trunk/ELF/Threads.h
>> >> URL:
>> >> http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Threads.h?rev=302613&r1=302612&r2=302613&view=diff
>> >>
>> >> ==============================================================================
>> >> --- lld/trunk/ELF/Threads.h (original)
>> >> +++ lld/trunk/ELF/Threads.h Tue May  9 20:16:22 2017
>> >> @@ -71,19 +71,17 @@ namespace elf {
>> >>  template <class IterTy, class FuncTy>
>> >>  void parallelForEach(IterTy Begin, IterTy End, FuncTy Fn) {
>> >>    if (Config->Threads)
>> >> -    parallel_for_each(Begin, End, Fn);
>> >> +    for_each(parallel::par, Begin, End, Fn);
>> >>    else
>> >> -    std::for_each(Begin, End, Fn);
>> >> +    for_each(parallel::seq, Begin, End, Fn);
>> >>  }
>> >>
>> >>  inline void parallelFor(size_t Begin, size_t End,
>> >>                          std::function<void(size_t)> Fn) {
>> >> -  if (Config->Threads) {
>> >> -    parallel_for(Begin, End, Fn);
>> >> -  } else {
>> >> -    for (size_t I = Begin; I < End; ++I)
>> >> -      Fn(I);
>> >> -  }
>> >> +  if (Config->Threads)
>> >> +    for_each_n(parallel::par, Begin, End, Fn);
>> >> +  else
>> >> +    for_each_n(parallel::seq, Begin, End, Fn);
>> >>  }
>> >>  }
>> >>  }
>> >>
>> >> Modified: lld/trunk/include/lld/Core/Parallel.h
>> >> URL:
>> >> http://llvm.org/viewvc/llvm-project/lld/trunk/include/lld/Core/Parallel.h?rev=302613&r1=302612&r2=302613&view=diff
>> >>
>> >> ==============================================================================
>> >> --- lld/trunk/include/lld/Core/Parallel.h (original)
>> >> +++ lld/trunk/include/lld/Core/Parallel.h Tue May  9 20:16:22 2017
>> >> @@ -12,8 +12,9 @@
>> >>
>> >>  #include "lld/Core/LLVM.h"
>> >>  #include "lld/Core/TaskGroup.h"
>> >> -#include "llvm/Support/MathExtras.h"
>> >> +#include "llvm/ADT/STLExtras.h"
>> >>  #include "llvm/Config/llvm-config.h"
>> >> +#include "llvm/Support/MathExtras.h"
>> >>
>> >>  #include <algorithm>
>> >>
>> >> @@ -24,25 +25,40 @@
>> >>
>> >>  namespace lld {
>> >>
>> >> -#if !LLVM_ENABLE_THREADS
>> >> -template <class RandomAccessIterator, class Comparator>
>> >> -void parallel_sort(
>> >> -    RandomAccessIterator Start, RandomAccessIterator End,
>> >> -    const Comparator &Comp = std::less<
>> >> -        typename
>> >> std::iterator_traits<RandomAccessIterator>::value_type>()) {
>> >> -  std::sort(Start, End, Comp);
>> >> -}
>> >> -#elif defined(_MSC_VER)
>> >> -// Use ppl parallel_sort on Windows.
>> >> +namespace parallel {
>> >> +struct sequential_execution_policy {};
>> >> +struct parallel_execution_policy {};
>> >> +
>> >> +template <typename T>
>> >> +struct is_execution_policy
>> >> +    : public std::integral_constant<
>> >> +          bool, llvm::is_one_of<T, sequential_execution_policy,
>> >> +                                parallel_execution_policy>::value> {};
>> >> +
>> >> +constexpr sequential_execution_policy seq{};
>> >> +constexpr parallel_execution_policy par{};
>> >> +
>> >> +#if LLVM_ENABLE_THREADS
>> >> +
>> >> +namespace detail {
>> >> +
>> >> +#if defined(_MSC_VER)
>> >>  template <class RandomAccessIterator, class Comparator>
>> >> -void parallel_sort(
>> >> -    RandomAccessIterator Start, RandomAccessIterator End,
>> >> -    const Comparator &Comp = std::less<
>> >> -        typename
>> >> std::iterator_traits<RandomAccessIterator>::value_type>()) {
>> >> +void parallel_sort(RandomAccessIterator Start, RandomAccessIterator
>> >> End,
>> >> +                   const Comparator &Comp) {
>> >>    concurrency::parallel_sort(Start, End, Comp);
>> >>  }
>> >> +template <class IterTy, class FuncTy>
>> >> +void parallel_for_each(IterTy Begin, IterTy End, FuncTy Fn) {
>> >> +  concurrency::parallel_for_each(Begin, End, Fn);
>> >> +}
>> >> +
>> >> +template <class IndexTy, class FuncTy>
>> >> +void parallel_for_each_n(IndexTy Begin, IndexTy End, FuncTy Fn) {
>> >> +  concurrency::parallel_for(Begin, End, Fn);
>> >> +}
>> >> +
>> >>  #else
>> >> -namespace detail {
>> >>  const ptrdiff_t MinParallelSize = 1024;
>> >>
>> >>  /// \brief Inclusive median.
>> >> @@ -83,46 +99,15 @@ void parallel_quick_sort(RandomAccessIte
>> >>    });
>> >>    parallel_quick_sort(Pivot + 1, End, Comp, TG, Depth - 1);
>> >>  }
>> >> -}
>> >>
>> >>  template <class RandomAccessIterator, class Comparator>
>> >> -void parallel_sort(
>> >> -    RandomAccessIterator Start, RandomAccessIterator End,
>> >> -    const Comparator &Comp = std::less<
>> >> -        typename
>> >> std::iterator_traits<RandomAccessIterator>::value_type>()) {
>> >> +void parallel_sort(RandomAccessIterator Start, RandomAccessIterator
>> >> End,
>> >> +                   const Comparator &Comp) {
>> >>    TaskGroup TG;
>> >> -  detail::parallel_quick_sort(Start, End, Comp, TG,
>> >> -                              llvm::Log2_64(std::distance(Start, End))
>> >> + 1);
>> >> -}
>> >> -#endif
>> >> -
>> >> -template <class T> void parallel_sort(T *Start, T *End) {
>> >> -  parallel_sort(Start, End, std::less<T>());
>> >> -}
>> >> -
>> >> -#if !LLVM_ENABLE_THREADS
>> >> -template <class IterTy, class FuncTy>
>> >> -void parallel_for_each(IterTy Begin, IterTy End, FuncTy Fn) {
>> >> -  std::for_each(Begin, End, Fn);
>> >> -}
>> >> -
>> >> -template <class IndexTy, class FuncTy>
>> >> -void parallel_for(IndexTy Begin, IndexTy End, FuncTy Fn) {
>> >> -  for (IndexTy I = Begin; I != End; ++I)
>> >> -    Fn(I);
>> >> -}
>> >> -#elif defined(_MSC_VER)
>> >> -// Use ppl parallel_for_each on Windows.
>> >> -template <class IterTy, class FuncTy>
>> >> -void parallel_for_each(IterTy Begin, IterTy End, FuncTy Fn) {
>> >> -  concurrency::parallel_for_each(Begin, End, Fn);
>> >> +  parallel_quick_sort(Start, End, Comp, TG,
>> >> +                      llvm::Log2_64(std::distance(Start, End)) + 1);
>> >>  }
>> >>
>> >> -template <class IndexTy, class FuncTy>
>> >> -void parallel_for(IndexTy Begin, IndexTy End, FuncTy Fn) {
>> >> -  concurrency::parallel_for(Begin, End, Fn);
>> >> -}
>> >> -#else
>> >>  template <class IterTy, class FuncTy>
>> >>  void parallel_for_each(IterTy Begin, IterTy End, FuncTy Fn) {
>> >>    // TaskGroup has a relatively high overhead, so we want to reduce
>> >> @@ -142,7 +127,7 @@ void parallel_for_each(IterTy Begin, Ite
>> >>  }
>> >>
>> >>  template <class IndexTy, class FuncTy>
>> >> -void parallel_for(IndexTy Begin, IndexTy End, FuncTy Fn) {
>> >> +void parallel_for_each_n(IndexTy Begin, IndexTy End, FuncTy Fn) {
>> >>    ptrdiff_t TaskSize = (End - Begin) / 1024;
>> >>    if (TaskSize == 0)
>> >>      TaskSize = 1;
>> >> @@ -160,7 +145,65 @@ void parallel_for(IndexTy Begin, IndexTy
>> >>        Fn(J);
>> >>    });
>> >>  }
>> >> +
>> >> +#endif
>> >> +
>> >> +template <typename Iter>
>> >> +using DefComparator =
>> >> +    std::less<typename std::iterator_traits<Iter>::value_type>;
>> >> +
>> >> +} // namespace detail
>> >>  #endif
>> >> +
>> >> +// sequential algorithm implementations.
>> >> +template <class Policy, class RandomAccessIterator,
>> >> +          class Comparator =
>> >> detail::DefComparator<RandomAccessIterator>>
>> >> +void sort(Policy policy, RandomAccessIterator Start,
>> >> RandomAccessIterator End,
>> >> +          const Comparator &Comp = Comparator()) {
>> >> +  static_assert(is_execution_policy<Policy>::value,
>> >> +                "Invalid execution policy!");
>> >> +  std::sort(Start, End, Comp);
>> >> +}
>> >> +
>> >> +template <class Policy, class IterTy, class FuncTy>
>> >> +void for_each(Policy policy, IterTy Begin, IterTy End, FuncTy Fn) {
>> >> +  static_assert(is_execution_policy<Policy>::value,
>> >> +                "Invalid execution policy!");
>> >> +  std::for_each(Begin, End, Fn);
>> >> +}
>> >> +
>> >> +template <class Policy, class IndexTy, class FuncTy>
>> >> +void for_each_n(Policy policy, IndexTy Begin, IndexTy End, FuncTy Fn)
>> >> {
>> >> +  static_assert(is_execution_policy<Policy>::value,
>> >> +                "Invalid execution policy!");
>> >> +  for (IndexTy I = Begin; I != End; ++I)
>> >> +    Fn(I);
>> >> +}
>> >> +
>> >> +// Parallel algorithm implementations, only available when
>> >> LLVM_ENABLE_THREADS
>> >> +// is true.
>> >> +#if defined(LLVM_ENABLE_THREADS)
>> >> +template <class RandomAccessIterator,
>> >> +          class Comparator =
>> >> detail::DefComparator<RandomAccessIterator>>
>> >> +void sort(parallel_execution_policy policy, RandomAccessIterator
>> >> Start,
>> >> +          RandomAccessIterator End, const Comparator &Comp =
>> >> Comparator()) {
>> >> +  detail::parallel_sort(Start, End, Comp);
>> >> +}
>> >> +
>> >> +template <class IterTy, class FuncTy>
>> >> +void for_each(parallel_execution_policy policy, IterTy Begin, IterTy
>> >> End,
>> >> +              FuncTy Fn) {
>> >> +  detail::parallel_for_each(Begin, End, Fn);
>> >> +}
>> >> +
>> >> +template <class IndexTy, class FuncTy>
>> >> +void for_each_n(parallel_execution_policy policy, IndexTy Begin,
>> >> IndexTy End,
>> >> +                FuncTy Fn) {
>> >> +  detail::parallel_for_each_n(Begin, End, Fn);
>> >> +}
>> >> +#endif
>> >> +
>> >> +} // namespace parallel
>> >>  } // End namespace lld
>> >>
>> >>  #endif // LLD_CORE_PARALLEL_H
>> >>
>> >> Modified: lld/trunk/lib/ReaderWriter/MachO/LayoutPass.cpp
>> >> URL:
>> >> http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/LayoutPass.cpp?rev=302613&r1=302612&r2=302613&view=diff
>> >>
>> >> ==============================================================================
>> >> --- lld/trunk/lib/ReaderWriter/MachO/LayoutPass.cpp (original)
>> >> +++ lld/trunk/lib/ReaderWriter/MachO/LayoutPass.cpp Tue May  9 20:16:22
>> >> 2017
>> >> @@ -461,10 +461,10 @@ llvm::Error LayoutPass::perform(SimpleFi
>> >>    });
>> >>
>> >>    std::vector<LayoutPass::SortKey> vec = decorate(atomRange);
>> >> -  parallel_sort(vec.begin(), vec.end(),
>> >> -      [&](const LayoutPass::SortKey &l, const LayoutPass::SortKey &r)
>> >> -> bool {
>> >> -        return compareAtoms(l, r, _customSorter);
>> >> -      });
>> >> +  sort(parallel::par, vec.begin(), vec.end(),
>> >> +       [&](const LayoutPass::SortKey &l, const LayoutPass::SortKey &r)
>> >> -> bool {
>> >> +         return compareAtoms(l, r, _customSorter);
>> >> +       });
>> >>    DEBUG(checkTransitivity(vec, _customSorter));
>> >>    undecorate(atomRange, vec);
>> >>
>> >>
>> >> Modified: lld/trunk/unittests/CoreTests/ParallelTest.cpp
>> >> URL:
>> >> http://llvm.org/viewvc/llvm-project/lld/trunk/unittests/CoreTests/ParallelTest.cpp?rev=302613&r1=302612&r2=302613&view=diff
>> >>
>> >> ==============================================================================
>> >> --- lld/trunk/unittests/CoreTests/ParallelTest.cpp (original)
>> >> +++ lld/trunk/unittests/CoreTests/ParallelTest.cpp Tue May  9 20:16:22
>> >> 2017
>> >> @@ -26,7 +26,7 @@ TEST(Parallel, sort) {
>> >>    for (auto &i : array)
>> >>      i = dist(randEngine);
>> >>
>> >> -  lld::parallel_sort(std::begin(array), std::end(array));
>> >> +  sort(lld::parallel::par, std::begin(array), std::end(array));
>> >>    ASSERT_TRUE(std::is_sorted(std::begin(array), std::end(array)));
>> >>  }
>> >>
>> >> @@ -36,7 +36,7 @@ TEST(Parallel, parallel_for) {
>> >>    // writing.
>> >>    uint32_t range[2050];
>> >>    std::fill(range, range + 2050, 1);
>> >> -  lld::parallel_for(0, 2049, [&range](size_t I) { ++range[I]; });
>> >> +  for_each_n(lld::parallel::par, 0, 2049, [&range](size_t I) {
>> >> ++range[I]; });
>> >>
>> >>    uint32_t expected[2049];
>> >>    std::fill(expected, expected + 2049, 2);
>> >>
>> >>
>> >> _______________________________________________
>> >> llvm-commits mailing list
>> >> llvm-commits at lists.llvm.org
>> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits


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