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8350462: MethodTypeForm.LF_INTERPRET can cache the MemberName instead #24468

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8350462: MethodTypeForm.LF_INTERPRET can cache the MemberName instead #24468

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8350462: MethodTypeForm.LF_INTERPRET can cache the MemberName instead
linzihao1999 Apr 1, 2025
e70fb81
Merge branch 'openjdk:master' into JDK-8350462
linzihao1999 Apr 5, 2025
3ce154e
remove LF_INTERPRET
linzihao1999 Apr 6, 2025
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21 changes: 7 additions & 14 deletions src/java.base/share/classes/java/lang/invoke/LambdaForm.java
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Original file line number Diff line number Diff line change
Expand Up @@ -371,14 +371,6 @@ static LambdaForm create(int arity, Name[] names, boolean forceInline, Kind kind
return create(arity, names, DEFAULT_RESULT, forceInline, DEFAULT_CUSTOMIZED, kind);
}

private static LambdaForm createBlankForType(MethodType mt) {
// Make a dummy blank lambda form.
// It is used as a template for managing the invocation of similar forms that are non-empty.
// Called only from getPreparedForm.
LambdaForm form = new LambdaForm(0, 0, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, new Name[0], Kind.GENERIC);
return form;
}

private static int fixResult(int result, Name[] names) {
if (result == LAST_RESULT)
result = names.length - 1; // might still be void
Expand Down Expand Up @@ -785,14 +777,15 @@ public void prepare() {
return;
}
MethodType mtype = methodType();
LambdaForm prep = mtype.form().cachedLambdaForm(MethodTypeForm.LF_INTERPRET);
if (prep == null) {
MethodTypeForm form = mtype.form();

MemberName entry = form.cachedInterpretEntry();
if (entry == null) {
assert (isValidSignature(basicTypeSignature()));
prep = LambdaForm.createBlankForType(mtype);
prep.vmentry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
prep = mtype.form().setCachedLambdaForm(MethodTypeForm.LF_INTERPRET, prep);
entry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
entry = form.setCachedInterpretEntry(entry);
}
this.vmentry = prep.vmentry;
this.vmentry = entry;
// TO DO: Maybe add invokeGeneric, invokeWithArguments
}

Expand Down
16 changes: 15 additions & 1 deletion src/java.base/share/classes/java/lang/invoke/MethodTypeForm.java
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,8 @@ final class MethodTypeForm {
// Cached lambda form information, for basic types only:
private final Object[] lambdaForms;

private SoftReference<MemberName> interpretEntry;

// Indexes into lambdaForms:
static final int
LF_INVVIRTUAL = 0, // DMH invokeVirtual
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You can remove the LF_INTERPRET constant from this list.

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OK, removed it.

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Now the index 6 is left unused in the LF cache array - we can leave it empty and renumber the cache indices when we add a new entry to cache.

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Got it, thanks for the explanation.

Expand All @@ -72,7 +74,6 @@ final class MethodTypeForm {
LF_NEWINVSPECIAL = 3,
LF_INVINTERFACE = 4,
LF_INVSTATIC_INIT = 5, // DMH invokeStatic with <clinit> barrier
LF_INTERPRET = 6, // LF interpreter
LF_REBIND = 7, // BoundMethodHandle
LF_DELEGATE = 8, // DelegatingMethodHandle
LF_DELEGATE_BLOCK_INLINING = 9, // Counting DelegatingMethodHandle w/ @DontInline
Expand Down Expand Up @@ -162,6 +163,19 @@ public synchronized LambdaForm setCachedLambdaForm(int which, LambdaForm form) {
return form;
}

public MemberName cachedInterpretEntry() {
return (interpretEntry == null) ? null : interpretEntry.get();
}

public synchronized MemberName setCachedInterpretEntry(MemberName mn) {
MemberName prev = cachedInterpretEntry();
if (prev != null) {
return prev;
}
this.interpretEntry = new SoftReference<>(mn);
return mn;
}

/**
* Build an MTF for a given type, which must have all references erased to Object.
* This MTF will stand for that type and all un-erased variations.
Expand Down