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Backport: 8261449: Micro-optimize JVM_LatestUserDefinedLoader #116

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Merged
duanyangjing merged 1 commit into from
Apr 8, 2026
Merged

Backport: 8261449: Micro-optimize JVM_LatestUserDefinedLoader #116

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13 changes: 4 additions & 9 deletions src/hotspot/share/prims/jvm.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3310,24 +3310,19 @@ JVM_END

JVM_ENTRY(jobject, JVM_LatestUserDefinedLoader(JNIEnv *env))
for (vframeStream vfst(thread); !vfst.at_end(); vfst.next()) {
#if HOTSPOT_TARGET_CLASSLIB == 8
// UseNewReflection
vfst.skip_reflection_related_frames(); // Only needed for 1.4 reflection
oop loader = vfst.method()->method_holder()->class_loader();
if (loader != NULL && !SystemDictionary::is_ext_class_loader(Handle(THREAD, loader))) {
return JNIHandles::make_local(THREAD, loader);
}
#else
InstanceKlass* ik = vfst.method()->method_holder();
oop loader = ik->class_loader();
#if HOTSPOT_TARGET_CLASSLIB == 8
if (loader != nullptr && !SystemDictionary::is_ext_class_loader(Handle(THREAD, loader))) {
#else
if (loader != NULL && !SystemDictionary::is_platform_class_loader(loader)) {
#endif // HOTSPOT_TARGET_CLASSLIB == 8
// Skip reflection related frames
if (!ik->is_subclass_of(vmClasses::reflect_MethodAccessorImpl_klass()) &&
!ik->is_subclass_of(vmClasses::reflect_ConstructorAccessorImpl_klass())) {
return JNIHandles::make_local(THREAD, loader);
}
}
#endif // HOTSPOT_TARGET_CLASSLIB == 8
}
return NULL;
JVM_END
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9 changes: 0 additions & 9 deletions src/hotspot/share/runtime/vframe.cpp
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Expand Up @@ -604,15 +604,6 @@ javaVFrame* vframeStreamCommon::asJavaVFrame() {
return result;
}

#if HOTSPOT_TARGET_CLASSLIB == 8
void vframeStreamCommon::skip_reflection_related_frames() {
while (!at_end() &&
(method()->method_holder()->is_subclass_of(vmClasses::reflect_MethodAccessorImpl_klass()) ||
method()->method_holder()->is_subclass_of(vmClasses::reflect_ConstructorAccessorImpl_klass()))) {
next();
}
}
#endif

#ifndef PRODUCT
void vframe::print() {
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5 changes: 0 additions & 5 deletions src/hotspot/share/runtime/vframe.hpp
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Expand Up @@ -335,11 +335,6 @@ class vframeStreamCommon : StackObj {
// special security frames and prefixed native methods
void security_get_caller_frame(int depth);

#if HOTSPOT_TARGET_CLASSLIB == 8
// Helper routine for JVM_LatestUserDefinedLoader -- needed for 1.4
// reflection implementation
void skip_reflection_related_frames();
#endif
};

class vframeStream : public vframeStreamCommon {
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