Adjust arguments to Unsafe array operations while offheap is enabled (FIXED) #20090
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When Unsafe.get()/put() is called on an array and offheap changes are enabled, adjust arguments so that dataAddr is passed in as base address of object Signed-off-by: midronij <[email protected]>
When Unsafe.compareAndSwap() is called on an array and offheap changes are enabled, adjust arguments so that dataAddr is passed in as base address of object Signed-off-by: midronij <[email protected]>
When the type of the object being passed in to Unsafe.get()/put() is
known at compile time, rather than generate runtime type checks, skip
to determining and generating the appropriate access block. There are
two cases in which we can do this:
1.) If the object is known to be an array, only generate the
arrayDirectAccessBlock and directAccessBlock (in case NULLCHK
fails).
2.) If the object is known to be non-array, non-java/lang/Class,
and non-java/lang/Object, only generate the directAccessBlock.
Signed-off-by: midronij <[email protected]>
For Unsafe.compareAndSwap(), do not generate array check IL or adjusted array access block if object type is known at compile time. Signed-off-by: midronij <[email protected]>
When offheap is enabled and the type of the object being operated on is unknown, there are three possible cases that need to be accounted for regarding the type of the object being operated on for Unsafe.get()/put(): 1.) array object 2.) java/lang/Class object 3.) none of the above Since case (3) is the most likely, we want the block corresponding to this case (directAccessBlock) to be on the fallthrough path. Signed-off-by: midronij <[email protected]>
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Add comments and update existing documentation/explanations to reflect changes made to inlining of Unsafe.get()/put() and compareAndSwap() to accommodate cases where offheap allocation is enabled. Signed-off-by: midronij <[email protected]>
A crash was occuring in Unsafe.get/put() case (6) when trying to modify the CFG to include the newly generated directAccessBlock. To avoid this, we can simply append the directAccessTreeTop onto the previous block (beforeCallBlock), which elimiates the need to update the CFG, since no new blocks are added. Additionally, without this commit, these two blocks (in addition to the one after the directAccessBlock, joinBlock), would get merged during block simplication anyways: so this fix eliminates the need to perform that optimization later down the line. Signed-off-by: midronij <[email protected]>
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midronij
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zl-wang
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Aug 30, 2024
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jenkins test sanity all jdk21 |
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ignoring pending status due to windows machine issue ... merging |
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Updated version of #17969 that addresses #19947.