Re: ResolvedMethodName::vmholder unused?
Where does the GC tracks the vmholder? I did a grep of 'vmholder' in all the source code and I can't find anything. There's a notion of injected fields in HotSpot which aren't present in class declaration, but present in the class at runtime (for details see JavaClasses::get_injected() called from ClassFileParser::parse_fields()). vmholder is an object field injected into ResolvedMethodName class. It's an ordinary object field, so there's no additional GC support needed to support it. Best regards, Vladimir Ivanov Thanks - Ioi On 5/7/18 5:45 PM, Vladimir Ivanov wrote: Ioi, Though the field is never accessed directly, ResolvedMethodName::vmholder is still tracked by GC and keeps the metadata it accompanies (RMN::vmtarget) alive until RMN is reachable. Best regards, Vladimir Ivanov On 5/7/18 17:29, Ioi Lam wrote: I don't see anywhere in HotSpot that uses java_lang_invoke_ResolvedMethodName::_vmholder_offset, which is declared here: http://hg.openjdk.java.net/jdk/jdk/file/7444101401b2/src/hotspot/share/classfile/javaClasses.hpp#l1057 http://hg.openjdk.java.net/jdk/jdk/file/9608f7f41c4e/src/java.base/share/classes/java/lang/invoke/MemberName.java#l75 I tried commenting out the initialization of this field and was able to run a simple Lambda test. diff -r 9255cb73f048 src/hotspot/share/classfile/javaClasses.cpp --- a/src/hotspot/share/classfile/javaClasses.cpp Mon May 07 15:29:31 2018 -0700 +++ b/src/hotspot/share/classfile/javaClasses.cpp Mon May 07 17:27:27 2018 -0700 @@ -3808,7 +3808,7 @@ // Add a reference to the loader (actually mirror because anonymous classes will not have // distinct loaders) to ensure the metadata is kept alive. // This mirror may be different than the one in clazz field. - new_resolved_method->obj_field_put(_vmholder_offset, m->method_holder()->java_mirror()); + //new_resolved_method->obj_field_put(_vmholder_offset, m->method_holder()->java_mirror()); resolved_method = ResolvedMethodTable::add_method(Handle(THREAD, new_resolved_method)); } Any plans to use vmholder in the future? Or, is this used by any non-HotSpot VM? If no one uses it, I'll file an RFE to remove it, so we can save a pointer per MemberName. Thanks - Ioi ___ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev ___ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
Re: ResolvedMethodName::vmholder unused?
Hi Vladimir, Where does the GC tracks the vmholder? I did a grep of 'vmholder' in all the source code and I can't find anything. Thanks - Ioi On 5/7/18 5:45 PM, Vladimir Ivanov wrote: Ioi, Though the field is never accessed directly, ResolvedMethodName::vmholder is still tracked by GC and keeps the metadata it accompanies (RMN::vmtarget) alive until RMN is reachable. Best regards, Vladimir Ivanov On 5/7/18 17:29, Ioi Lam wrote: I don't see anywhere in HotSpot that uses java_lang_invoke_ResolvedMethodName::_vmholder_offset, which is declared here: http://hg.openjdk.java.net/jdk/jdk/file/7444101401b2/src/hotspot/share/classfile/javaClasses.hpp#l1057 http://hg.openjdk.java.net/jdk/jdk/file/9608f7f41c4e/src/java.base/share/classes/java/lang/invoke/MemberName.java#l75 I tried commenting out the initialization of this field and was able to run a simple Lambda test. diff -r 9255cb73f048 src/hotspot/share/classfile/javaClasses.cpp --- a/src/hotspot/share/classfile/javaClasses.cpp Mon May 07 15:29:31 2018 -0700 +++ b/src/hotspot/share/classfile/javaClasses.cpp Mon May 07 17:27:27 2018 -0700 @@ -3808,7 +3808,7 @@ // Add a reference to the loader (actually mirror because anonymous classes will not have // distinct loaders) to ensure the metadata is kept alive. // This mirror may be different than the one in clazz field. - new_resolved_method->obj_field_put(_vmholder_offset, m->method_holder()->java_mirror()); + //new_resolved_method->obj_field_put(_vmholder_offset, m->method_holder()->java_mirror()); resolved_method = ResolvedMethodTable::add_method(Handle(THREAD, new_resolved_method)); } Any plans to use vmholder in the future? Or, is this used by any non-HotSpot VM? If no one uses it, I'll file an RFE to remove it, so we can save a pointer per MemberName. Thanks - Ioi ___ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev ___ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
Re: ResolvedMethodName::vmholder unused?
Ioi, Though the field is never accessed directly, ResolvedMethodName::vmholder is still tracked by GC and keeps the metadata it accompanies (RMN::vmtarget) alive until RMN is reachable. Best regards, Vladimir Ivanov On 5/7/18 17:29, Ioi Lam wrote: I don't see anywhere in HotSpot that uses java_lang_invoke_ResolvedMethodName::_vmholder_offset, which is declared here: http://hg.openjdk.java.net/jdk/jdk/file/7444101401b2/src/hotspot/share/classfile/javaClasses.hpp#l1057 http://hg.openjdk.java.net/jdk/jdk/file/9608f7f41c4e/src/java.base/share/classes/java/lang/invoke/MemberName.java#l75 I tried commenting out the initialization of this field and was able to run a simple Lambda test. diff -r 9255cb73f048 src/hotspot/share/classfile/javaClasses.cpp --- a/src/hotspot/share/classfile/javaClasses.cpp Mon May 07 15:29:31 2018 -0700 +++ b/src/hotspot/share/classfile/javaClasses.cpp Mon May 07 17:27:27 2018 -0700 @@ -3808,7 +3808,7 @@ // Add a reference to the loader (actually mirror because anonymous classes will not have // distinct loaders) to ensure the metadata is kept alive. // This mirror may be different than the one in clazz field. - new_resolved_method->obj_field_put(_vmholder_offset, m->method_holder()->java_mirror()); + //new_resolved_method->obj_field_put(_vmholder_offset, m->method_holder()->java_mirror()); resolved_method = ResolvedMethodTable::add_method(Handle(THREAD, new_resolved_method)); } Any plans to use vmholder in the future? Or, is this used by any non-HotSpot VM? If no one uses it, I'll file an RFE to remove it, so we can save a pointer per MemberName. Thanks - Ioi ___ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev ___ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
ResolvedMethodName::vmholder unused?
I don't see anywhere in HotSpot that uses java_lang_invoke_ResolvedMethodName::_vmholder_offset, which is declared here: http://hg.openjdk.java.net/jdk/jdk/file/7444101401b2/src/hotspot/share/classfile/javaClasses.hpp#l1057 http://hg.openjdk.java.net/jdk/jdk/file/9608f7f41c4e/src/java.base/share/classes/java/lang/invoke/MemberName.java#l75 I tried commenting out the initialization of this field and was able to run a simple Lambda test. diff -r 9255cb73f048 src/hotspot/share/classfile/javaClasses.cpp --- a/src/hotspot/share/classfile/javaClasses.cpp Mon May 07 15:29:31 2018 -0700 +++ b/src/hotspot/share/classfile/javaClasses.cpp Mon May 07 17:27:27 2018 -0700 @@ -3808,7 +3808,7 @@ // Add a reference to the loader (actually mirror because anonymous classes will not have // distinct loaders) to ensure the metadata is kept alive. // This mirror may be different than the one in clazz field. - new_resolved_method->obj_field_put(_vmholder_offset, m->method_holder()->java_mirror()); + //new_resolved_method->obj_field_put(_vmholder_offset, m->method_holder()->java_mirror()); resolved_method = ResolvedMethodTable::add_method(Handle(THREAD, new_resolved_method)); } Any plans to use vmholder in the future? Or, is this used by any non-HotSpot VM? If no one uses it, I'll file an RFE to remove it, so we can save a pointer per MemberName. Thanks - Ioi ___ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
