50 lines
1.5 KiB
Diff
50 lines
1.5 KiB
Diff
# HG changeset patch
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# User Jon Coppeard <jcoppeard@mozilla.com>
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# Date 1603288236 0
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# Wed Oct 21 13:50:36 2020 +0000
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# Node ID 7e223284a9225c66b590aaad671c7448d1ff0b57
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# Parent dfcb025567da9e33bf724520e0146fef3d776d5f
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Bug 1670358 - Don't use realloc for shrinking nsTArrays and similar when RelocationStrategy::allowRealloc is false r=sg
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My original patch handled the grow case but not the shrink case. When the
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current and new allocation sizes are in different size classes jemalloc's
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realloc will move the allocation when shrinking, not just truncate the existing
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one.
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Differential Revision: https://phabricator.services.mozilla.com/D93654
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diff -r dfcb025567da -r 7e223284a922 xpcom/ds/nsTArray-inl.h
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--- a/xpcom/ds/nsTArray-inl.h Thu Oct 22 07:36:15 2020 +0000
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+++ b/xpcom/ds/nsTArray-inl.h Wed Oct 21 13:50:36 2020 +0000
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@@ -259,10 +259,27 @@
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}
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size_type size = sizeof(Header) + length * aElemSize;
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- void* ptr = nsTArrayFallibleAllocator::Realloc(mHdr, size);
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- if (!ptr) {
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- return;
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+ void* ptr;
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+
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+ if (!RelocationStrategy::allowRealloc) {
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+ // Malloc() and copy.
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+ ptr = static_cast<Header*>(nsTArrayFallibleAllocator::Malloc(size));
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+ if (!ptr) {
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+ return;
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+ }
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+
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+ RelocationStrategy::RelocateNonOverlappingRegionWithHeader(
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+ ptr, mHdr, Length(), aElemSize);
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+
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+ nsTArrayFallibleAllocator::Free(mHdr);
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+ } else {
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+ // Realloc() existing data.
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+ ptr = nsTArrayFallibleAllocator::Realloc(mHdr, size);
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+ if (!ptr) {
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+ return;
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+ }
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}
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+
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mHdr = static_cast<Header*>(ptr);
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mHdr->mCapacity = length;
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}
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