Commit 824a2881 authored by Jez Ng's avatar Jez Ng
Browse files

[lld-macho][nfc] Simplify MarkLive.cpp using `if constexpr` 

No significant perf diff, as expected.

             base           diff           difference (95% CI)
  sys_time   1.722 ± 0.030  1.727 ± 0.027  [  -0.6% ..   +1.2%]
  user_time  5.081 ± 0.032  5.087 ± 0.030  [  -0.2% ..   +0.4%]
  wall_time  6.008 ± 0.056  6.029 ± 0.053  [  -0.1% ..   +0.8%]
  samples    25             37

Reviewed By: #lld-macho, oontvoo, thakis, BertalanD

Differential Revision: https://reviews.llvm.org/D133014
parent ada51eed

lld/MachO/MarkLive.cpp

+37 −51
Original line number Diff line number Diff line
@@ -57,7 +57,6 @@ public: 
private:

  void enqueue(InputSection *isec, uint64_t off, const WorklistEntry *prev);

  void addSym(Symbol *s, const WorklistEntry *prev);

  void printWhyLive(Symbol *s, const WorklistEntry *prev);

  const InputSection *getInputSection(const WorklistEntry *) const;

  WorklistEntry *makeEntry(InputSection *, const WorklistEntry *prev) const;
@@ -82,23 +81,7 @@ void MarkLiveImpl<RecordWhyLive>::enqueue( 
  }

}



template <bool RecordWhyLive>

void MarkLiveImpl<RecordWhyLive>::addSym(

    Symbol *s,

    const typename MarkLiveImpl<RecordWhyLive>::WorklistEntry *prev) {

  if (s->used)

    return;

  s->used = true;

  printWhyLive(s, prev);

  if (auto *d = dyn_cast<Defined>(s)) {

    if (d->isec)

      enqueue(d->isec, d->value, prev);

    if (d->unwindEntry)

      enqueue(d->unwindEntry, 0, prev);

  }

}



static void printWhyLiveImpl(const Symbol *s, const WhyLiveEntry *prev) {

static void printWhyLive(const Symbol *s, const WhyLiveEntry *prev) {

  std::string out = toString(*s) + " from " + toString(s->getFile());

  int indent = 2;

  for (const WhyLiveEntry *entry = prev; entry;
@@ -113,45 +96,48 @@ static void printWhyLiveImpl(const Symbol *s, const WhyLiveEntry *prev) { 
  message(out);

}



// NOTE: if/when `constexpr if` becomes available, we can simplify a lot of

// the partial template specializations below.



template <>

void MarkLiveImpl<true>::printWhyLive(Symbol *s, const WhyLiveEntry *prev) {

template <bool RecordWhyLive>

void MarkLiveImpl<RecordWhyLive>::addSym(

    Symbol *s,

    const typename MarkLiveImpl<RecordWhyLive>::WorklistEntry *prev) {

  if (s->used)

    return;

  s->used = true;

  if constexpr (RecordWhyLive)

    if (!config->whyLive.empty() && config->whyLive.match(s->getName()))

    printWhyLiveImpl(s, prev);

      printWhyLive(s, prev);

  if (auto *d = dyn_cast<Defined>(s)) {

    if (d->isec)

      enqueue(d->isec, d->value, prev);

    if (d->unwindEntry)

      enqueue(d->unwindEntry, 0, prev);

  }



template <>

void MarkLiveImpl<false>::printWhyLive(Symbol *s, const InputSection *prev) {}



template <>

const InputSection *

MarkLiveImpl<true>::getInputSection(const WhyLiveEntry *entry) const {

  return entry->isec;

}



template <>

const InputSection *

MarkLiveImpl<false>::getInputSection(const InputSection *isec) const {

  return isec;

template <bool RecordWhyLive>

const InputSection *MarkLiveImpl<RecordWhyLive>::getInputSection(

    const MarkLiveImpl<RecordWhyLive>::WorklistEntry *entry) const {

  if constexpr (RecordWhyLive)

    return entry->isec;

  else

    return entry;

}



template <>

typename MarkLiveImpl<true>::WorklistEntry *MarkLiveImpl<true>::makeEntry(

    InputSection *isec, const MarkLiveImpl<true>::WorklistEntry *prev) const {

template <bool RecordWhyLive>

typename MarkLiveImpl<RecordWhyLive>::WorklistEntry *

MarkLiveImpl<RecordWhyLive>::makeEntry(

    InputSection *isec,

    const MarkLiveImpl<RecordWhyLive>::WorklistEntry *prev) const {

  if constexpr (RecordWhyLive) {

    if (!isec) {

      assert(!prev);

      return nullptr;

    }

    return make<WhyLiveEntry>(isec, prev);

}



template <>

typename MarkLiveImpl<false>::WorklistEntry *MarkLiveImpl<false>::makeEntry(

    InputSection *isec, const MarkLiveImpl<false>::WorklistEntry *prev) const {

  } else {

    return isec;

  }

}



template <bool RecordWhyLive>

void MarkLiveImpl<RecordWhyLive>::markTransitively() {