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Allow inlining of java/lang/ref/Reference.refersTo method #13619

Merged
merged 3 commits into from
May 4, 2023
Merged

Allow inlining of java/lang/ref/Reference.refersTo method #13619

merged 3 commits into from
May 4, 2023

Commits on May 3, 2023

  1. Define queries to test whether Reference.refersTo can be inlined 

    The refersTo method was introduced to java.lang.ref.Reference in
Java 16.  The JIT compiler is able to inline the method under the same
conditions as it is able to inline Reference.getImpl.  This change
introduces new query methods and fields to check and record whether both
methods can be inlined.

The existing VM::isGetImplInliningSupported and
Compilation::setGetImplInlineable methods are invoked by OMR, so
they will remain in OpenJ9 until a subsequent pull request against OMR
replaces calls to those now obsolete methods.

Signed-off-by:  Henry Zongaro <zongaro@ca.ibm.com>
    @hzongaro
    hzongaro committed May 3, 2023
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  2. Allow inlining java/lang/ref/Reference.refersTo method 

    A Reference.refersTo(Object) method, introduced in Java 16, tests
whether the referent is the same object as the parameter.  Some
places in the JCL that used to perform comparisons of the referent using
Reference.get now use Reference.refersTo.  That affects performance of
such uses as Reference.get was implemented using a call to
Reference.getImpl which the JIT compiler recognized and inlined if
possible.

This change adds recognition of Reference.refersTo to the JIT, which
will now inline a call to it under the same conditions as it would
inline a call to Reference.getImpl.

Signed-off-by:  Henry Zongaro <zongaro@ca.ibm.com>
    @hzongaro
    hzongaro committed May 3, 2023
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  3. Ensure failing to inline Reference.refersTo is handled properly 

    If TR_J9VM::inlineNativeCall fails to inline a method, it sometimes
returns NULL and sometimes returns the original call node.  If it
returns NULL and the call node is a JNI call, the caller considers
whether any special processing of the call node is required by calling
TR::Node::processJNICall.

In the case of Reference.refersTo, the call is not inlined if the
Metronome GC policy is in effect, but inlineNativeCall was returning the
original call node.  That signalled to the caller that no special
consideration of whether the call node was a JNI call was needed, but it
was in fact needed.

Fixed this by having TR_J9VM::inlineNativeCall return NULL if it is
unable to inline Reference.refersTo.

Signed-off-by:  Henry Zongaro <zongaro@ca.ibm.com>
    @hzongaro
    hzongaro committed May 3, 2023
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