Supporting changes to add fences after volatile field stores #5689
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This helper will be consumed in the OpenJ9 downstream project. Signed-off-by: Filip Jeremic <[email protected]>
The `astoreEvaluator`, more precisely the `astoreHelper` has a path in which it is trying to identify the following tree pattern: ``` astore <x> aload <y> ``` and tries to generate an `MVC` instruction to perform the store. The problem with this is that it seems to generate a memory reference from the `node` only for the purposes of testing whether it has an index register (which it by the way cannot know until the memory reference is used within an instruction). The act of generating a memory reference is not side-effect free as the symref could have been unresolved and as such various metadata can be generated. The `astoreHelper` then goes ahead and creates another memory reference from the node and uses that for the `MVC` instruction. This means the metadata for handling unresolved symrefs could have been generated twice. Similarly to `directMemoryStoreHelper` we simply prevent this `MVC` reduction if the symref is unresolved. Signed-off-by: Filip Jeremic <[email protected]>
r30shah
changed the title
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@genie-omr build zlinux,zos |
fjeremic
approved these changes
Nov 25, 2020
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Changes in PR adds supporting changes to add fences after volatile field stores made in eclipse-openj9/openj9#11262.
Signed-off-by: Rahil Shah [email protected]