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8373039: Remove Incorrect Asserts in shenandoahScanRemembered

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Reviewed-by: wkemper, ysr, xpeng
This commit is contained in:
Ben Taylor 2025-12-04 22:11:48 +00:00 committed by Y. Srinivas Ramakrishna
parent 5ec5a6ea6c
commit c8b30da7ef
1 changed files with 3 additions and 13 deletions
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16
src/hotspot/share/gc/shenandoah/shenandoahScanRemembered.cpp
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@ -335,7 +335,6 @@ HeapWord* ShenandoahCardCluster::first_object_start(const size_t card_index, con
if (ctx->is_marked(p)) {
oop obj = cast_to_oop(p);
assert(oopDesc::is_oop(obj), "Should be an object");
assert(Klass::is_valid(obj->klass()), "Not a valid klass ptr");
assert(p + obj->size() > left, "This object should span start of card");
assert(p < right, "Result must precede right");
return p;
@ -362,15 +361,15 @@ HeapWord* ShenandoahCardCluster::first_object_start(const size_t card_index, con
// Recall that we already dealt with the co-initial object case above
assert(p < left, "obj should start before left");
// While it is safe to ask an object its size in the loop that
// follows, the (ifdef'd out) loop should never be needed.
// While it is safe to ask an object its size in the block that
// follows, the (ifdef'd out) block should never be needed.
// 1. we ask this question only for regions in the old generation, and those
// that are not humongous regions
// 2. there is no direct allocation ever by mutators in old generation
// regions walked by this code. Only GC will ever allocate in old regions,
// and then too only during promotion/evacuation phases. Thus there is no danger
// of races between reading from and writing to the object start array,
// or of asking partially initialized objects their size (in the loop below).
// or of asking partially initialized objects their size (in the ifdef below).
// Furthermore, humongous regions (and their dirty cards) are never processed
// by this code.
// 3. only GC asks this question during phases when it is not concurrently
@ -382,15 +381,6 @@ HeapWord* ShenandoahCardCluster::first_object_start(const size_t card_index, con
#ifdef ASSERT
oop obj = cast_to_oop(p);
assert(oopDesc::is_oop(obj), "Should be an object");
while (p + obj->size() < left) {
p += obj->size();
obj = cast_to_oop(p);
assert(oopDesc::is_oop(obj), "Should be an object");
assert(Klass::is_valid(obj->klass()), "Not a valid klass ptr");
// Check assumptions in previous block comment if this assert fires
fatal("Should never need forward walk in block start");
}
assert(p <= left, "p should start at or before left end of card");
assert(p + obj->size() > left, "obj should end after left end of card");
#endif // ASSERT
return p;