Title: [205810] trunk/Source
- Revision
- 205810
- Author
- fpi...@apple.com
- Date
- 2016-09-12 09:08:52 -0700 (Mon, 12 Sep 2016)
Log Message
DFG::forAllKilledOperands() could use a faster bitvector scan in the same-inline-stack fast path
https://bugs.webkit.org/show_bug.cgi?id=161849
Reviewed by Saam Barati.
Source/_javascript_Core:
This is a fairly obvious change. This turns a loop that would query each bit individually
into a loop that will process a word at a time. I would expect a very tiny progression in
DFG compile times.
This also gave me an opportunity to test and fix the new FastBitVector functionality.
* dfg/DFGForAllKills.h:
(JSC::DFG::forAllKilledOperands):
Source/WTF:
It turns out that templates make private fields weird. FastBitVectorImpl can't necessarily
touch privates in instances of different template specializations of itself. So, I added a
public method called wordView() that exposes the necessary private field.
* wtf/FastBitVector.h:
(WTF::FastBitVectorImpl::operator&):
(WTF::FastBitVectorImpl::operator|):
(WTF::FastBitVectorImpl::operator~):
(WTF::FastBitVectorImpl::forEachSetBit):
(WTF::FastBitVectorImpl::wordView):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (205809 => 205810)
--- trunk/Source/_javascript_Core/ChangeLog 2016-09-12 15:50:17 UTC (rev 205809)
+++ trunk/Source/_javascript_Core/ChangeLog 2016-09-12 16:08:52 UTC (rev 205810)
@@ -1,5 +1,21 @@
2016-09-11 Filip Pizlo <fpi...@apple.com>
+ DFG::forAllKilledOperands() could use a faster bitvector scan in the same-inline-stack fast path
+ https://bugs.webkit.org/show_bug.cgi?id=161849
+
+ Reviewed by Saam Barati.
+
+ This is a fairly obvious change. This turns a loop that would query each bit individually
+ into a loop that will process a word at a time. I would expect a very tiny progression in
+ DFG compile times.
+
+ This also gave me an opportunity to test and fix the new FastBitVector functionality.
+
+ * dfg/DFGForAllKills.h:
+ (JSC::DFG::forAllKilledOperands):
+
+2016-09-11 Filip Pizlo <fpi...@apple.com>
+
FastBitVector should have efficient and easy-to-use vector-vector operations
https://bugs.webkit.org/show_bug.cgi?id=161847
Modified: trunk/Source/_javascript_Core/dfg/DFGForAllKills.h (205809 => 205810)
--- trunk/Source/_javascript_Core/dfg/DFGForAllKills.h 2016-09-12 15:50:17 UTC (rev 205809)
+++ trunk/Source/_javascript_Core/dfg/DFGForAllKills.h 2016-09-12 16:08:52 UTC (rev 205810)
@@ -76,14 +76,10 @@
const FastBitVector& liveBefore = fullLiveness.getLiveness(before.bytecodeIndex);
const FastBitVector& liveAfter = fullLiveness.getLiveness(after.bytecodeIndex);
- // FIXME: Consider doing this instead:
- // (liveBefore & ~liveAfter).forEachSetBit(...)
- // https://bugs.webkit.org/show_bug.cgi?id=161849
- for (unsigned relativeLocal = codeBlock->m_numCalleeLocals; relativeLocal--;) {
- if (liveBefore[relativeLocal] && !liveAfter[relativeLocal])
+ (liveBefore & ~liveAfter).forEachSetBit(
+ [&] (size_t relativeLocal) {
functor(virtualRegisterForLocal(relativeLocal) + stackOffset);
- }
-
+ });
return;
}
Modified: trunk/Source/WTF/ChangeLog (205809 => 205810)
--- trunk/Source/WTF/ChangeLog 2016-09-12 15:50:17 UTC (rev 205809)
+++ trunk/Source/WTF/ChangeLog 2016-09-12 16:08:52 UTC (rev 205810)
@@ -1,5 +1,23 @@
2016-09-11 Filip Pizlo <fpi...@apple.com>
+ DFG::forAllKilledOperands() could use a faster bitvector scan in the same-inline-stack fast path
+ https://bugs.webkit.org/show_bug.cgi?id=161849
+
+ Reviewed by Saam Barati.
+
+ It turns out that templates make private fields weird. FastBitVectorImpl can't necessarily
+ touch privates in instances of different template specializations of itself. So, I added a
+ public method called wordView() that exposes the necessary private field.
+
+ * wtf/FastBitVector.h:
+ (WTF::FastBitVectorImpl::operator&):
+ (WTF::FastBitVectorImpl::operator|):
+ (WTF::FastBitVectorImpl::operator~):
+ (WTF::FastBitVectorImpl::forEachSetBit):
+ (WTF::FastBitVectorImpl::wordView):
+
+2016-09-11 Filip Pizlo <fpi...@apple.com>
+
FastBitVector should have efficient and easy-to-use vector-vector operations
https://bugs.webkit.org/show_bug.cgi?id=161847
Modified: trunk/Source/WTF/wtf/FastBitVector.h (205809 => 205810)
--- trunk/Source/WTF/wtf/FastBitVector.h 2016-09-12 15:50:17 UTC (rev 205809)
+++ trunk/Source/WTF/wtf/FastBitVector.h 2016-09-12 16:08:52 UTC (rev 205810)
@@ -258,7 +258,7 @@
private:
View m_view;
};
-
+
class FastBitVector;
template<typename Words>
@@ -323,24 +323,24 @@
template<typename OtherWords>
FastBitVectorImpl<FastBitVectorAndWords<typename Words::ViewType, typename OtherWords::ViewType>> operator&(const FastBitVectorImpl<OtherWords>& other) const
{
- return FastBitVectorImpl<FastBitVectorAndWords<typename Words::ViewType, typename OtherWords::ViewType>>(FastBitVectorAndWords<typename Words::ViewType, typename OtherWords::ViewType>(m_words.view(), other.m_words.view()));
+ return FastBitVectorImpl<FastBitVectorAndWords<typename Words::ViewType, typename OtherWords::ViewType>>(FastBitVectorAndWords<typename Words::ViewType, typename OtherWords::ViewType>(wordView(), other.wordView()));
}
template<typename OtherWords>
FastBitVectorImpl<FastBitVectorOrWords<typename Words::ViewType, typename OtherWords::ViewType>> operator|(const FastBitVectorImpl<OtherWords>& other) const
{
- return FastBitVectorImpl<FastBitVectorOrWords<typename Words::ViewType, typename OtherWords::ViewType>>(FastBitVectorOrWords<typename Words::ViewType, typename OtherWords::ViewType>(m_words.view(), other.m_words.view()));
+ return FastBitVectorImpl<FastBitVectorOrWords<typename Words::ViewType, typename OtherWords::ViewType>>(FastBitVectorOrWords<typename Words::ViewType, typename OtherWords::ViewType>(wordView(), other.wordView()));
}
FastBitVectorImpl<FastBitVectorNotWords<typename Words::ViewType>> operator~() const
{
- return FastBitVectorImpl<FastBitVectorNotWords<typename Words::ViewType>>(FastBitVectorNotWords<typename Words::ViewType>(m_words.view()));
+ return FastBitVectorImpl<FastBitVectorNotWords<typename Words::ViewType>>(FastBitVectorNotWords<typename Words::ViewType>(wordView()));
}
template<typename Func>
ALWAYS_INLINE void forEachSetBit(const Func& func) const
{
- size_t n = m_words.arrayLength();
+ size_t n = arrayLength();
for (size_t i = 0; i < n; ++i) {
uint32_t word = m_words.word(i);
size_t j = i * 32;
@@ -416,6 +416,8 @@
out.print((*this)[i] ? "1" : "-");
}
+ typename Words::ViewType wordView() const { return m_words.view(); }
+
private:
// You'd think that we could remove this friend if we used protected, but you'd be wrong,
// because templates.
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