Changes to the Java code looks fine to me - (and the overall approach in Unsafe seems sensible, but I'll defer to David for that)

Thanks
Maurizio

On 24/01/2020 09:58, Nick Gasson wrote:
Hi David,

On 01/24/20 14:35 pm, David Holmes wrote:
How about we align the size up to ADDRESS_SIZE (== HeapWordSize) in
Unsafe.allocateMemory() before the call to allocateMemoryChecks(). Like:

    bytes = ((bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1));

Then it will throw an IllegalArgumentException if the result is outside
the size_t range. And in the native code we can just assert that the
`size' argument is already aligned:

    assert(is_aligned(sz, HeapWordSize), "sz not aligned");
That seems quite reasonable.

I've done this here:

http://cr.openjdk.java.net/~ngasson/8237521/webrev.02/

Need to check bytes >= 0 before aligning up so that allocateMemory(-1)
still throws an IllegalArgumentException.

Tested with jdk_foreign and runtime/Unsafe/.


Thanks,
Nick

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