Integrated: 8263361: Incorrect arraycopy stub selected by C2 for SATB collectors

[Nils Eliasson]

On Mon, 15 Mar 2021 10:38:58 GMT, Nils Eliasson <neliasso at openjdk.org> wrote:

> This bug has only been reproduced with -XX:+StressReflectiveCode and -XX:-ReduceInitialCardMarks. If StressReflectiveCode is necessary isn't obvious.
> 
> I am fixing three things:
> 
> 1) When running with ReduceInitialCardMarks enabled the stubroutines for int- or long-arraycopy will be used for arraycopies to tightly allocated arrays (like when cloning). With ReduceInitialCardMarks disabled the oop-version will be used with barriers.
> 
> The generate_arraycopy method in PhaseMacroExpand have a bool dest_uninitialized field - but that field denotes that we have proven that no zeroing is necessary (since all fields will be written anyway). 
> 
> To fix this bug generate_unchecked_arraycopy with the param dest_uninitialized will need to be appended with a check for tighly coupled object-copies when ReduceInitialCardMarks is disabled.
> 
> 2) I also fix a bug in library_call kit where arraycopy for clones doesn't get marked as tightly coupled - The call to tightly_coupled_allocation can't be used when the IR isn't constructed yet.
> 
> 3) In stubroutines.cpp I fix so that the name of the arraycopy stubroutines gets appended with _uninit when appropriate. This shows up in ir-dumps and IGV.
> 
> Please review,
> Nils Eliasson

This pull request has now been integrated.

Changeset: 5d87a219
Author:    Nils Eliasson <neliasso at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/5d87a219
Stats:     43 lines in 3 files changed: 10 ins; 1 del; 32 mod

8263361: Incorrect arraycopy stub selected by C2 for SATB collectors

Reviewed-by: eosterlund, vlivanov

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PR: https://git.openjdk.java.net/jdk/pull/3008