Title: [294750] trunk/Source/WTF/wtf/FastBitVector.cpp
- Revision
- 294750
- Author
- [email protected]
- Date
- 2022-05-24 09:15:40 -0700 (Tue, 24 May 2022)
Log Message
Avoid unnecessary calls to fastZeroedMalloc() in FastBitVector
https://bugs.webkit.org/show_bug.cgi?id=240812
Reviewed by Yusuke Suzuki.
We were calling fastZeroedMalloc() which would allocate the memory and memset it to 0,
only to then overwrite all (or most) of that memory with memcpy().
* Source/WTF/wtf/FastBitVector.cpp:
(WTF::FastBitVectorWordOwner::setEqualsSlow):
(WTF::FastBitVectorWordOwner::resizeSlow):
Canonical link: https://commits.webkit.org/250918@main
Modified Paths
Diff
Modified: trunk/Source/WTF/wtf/FastBitVector.cpp (294749 => 294750)
--- trunk/Source/WTF/wtf/FastBitVector.cpp 2022-05-24 16:14:21 UTC (rev 294749)
+++ trunk/Source/WTF/wtf/FastBitVector.cpp 2022-05-24 16:15:40 UTC (rev 294750)
@@ -34,8 +34,7 @@
void FastBitVectorWordOwner::setEqualsSlow(const FastBitVectorWordOwner& other)
{
- uint32_t* newArray = static_cast<uint32_t*>(
- FastBitVectorMalloc::zeroedMalloc(other.arrayLength() * sizeof(uint32_t)));
+ uint32_t* newArray = static_cast<uint32_t*>(FastBitVectorMalloc::malloc(other.arrayLength() * sizeof(uint32_t)));
memcpy(newArray, other.m_words, other.arrayLength() * sizeof(uint32_t));
if (m_words)
FastBitVectorMalloc::free(m_words);
@@ -46,14 +45,15 @@
void FastBitVectorWordOwner::resizeSlow(size_t numBits)
{
size_t newLength = fastBitVectorArrayLength(numBits);
-
- RELEASE_ASSERT(newLength >= arrayLength());
+ size_t oldLength = arrayLength();
+ RELEASE_ASSERT(newLength >= oldLength);
- // Use fastCalloc instead of fastRealloc because we expect the common
+ // Use fastMalloc instead of fastRealloc because we expect the common
// use case for this method to be initializing the size of the bitvector.
- uint32_t* newArray = static_cast<uint32_t*>(FastBitVectorMalloc::zeroedMalloc(newLength * sizeof(uint32_t)));
- memcpy(newArray, m_words, arrayLength() * sizeof(uint32_t));
+ uint32_t* newArray = static_cast<uint32_t*>(FastBitVectorMalloc::malloc(newLength * sizeof(uint32_t)));
+ memcpy(newArray, m_words, oldLength * sizeof(uint32_t));
+ memset(newArray + oldLength, 0, (newLength - oldLength) * sizeof(uint32_t));
if (m_words)
FastBitVectorMalloc::free(m_words);
m_words = newArray;
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