RFR: 8247536: Support for pre-generated java.lang.invoke classes in CDS static archive
Yumin Qi
yumin.qi at oracle.com
Wed Aug 26 22:59:40 UTC 2020
Hi, Coleen
On 8/26/20 3:36 PM, Coleen Phillimore wrote:
>
>
> On 8/25/20 8:17 PM, Yumin Qi wrote:
>> Hi, Coleen and all
>>
>> I have updated at new link: http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-05/
>>
>> I changed find_class and add_to_hierarchy to public access in SystemDictionary for access from outside.
>>
>> new added find_class removed from ClassLoaderData.
>>
>> new added add_shared_to_hierarchy removed from SystemDictionaryShared.
> http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-05/src/hotspot/share/classfile/systemDictionaryShared.cpp.udiff.html
> http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-05/src/hotspot/share/classfile/systemDictionaryShared.hpp.udiff.html
>
> Thanks for making the change to call add_to_hierarchy directly in SystemDictionary, but it looks like you left it here in this patch.
>
Thanks! will remove them.
> Also, can lambdaFormInvokers.hpp/cpp be put in the classfile directory rather than the memory directory?
>
Sorry forget to do so. Will move them to classfile directory.
> Otherwise looks good. I didn't review the Java code.
>
About this part, I will wait for Mandy to come back from her vacation, she had a proposal and patch for consolidating JLI code.
Thanks
Yumin
> Coleen
>>
>> re-tested local on runtime/cds
>>
>>
>> Thanks
>>
>> Yumin
>>
>>
>> On 8/25/20 12:41 PM, Coleen Phillimore wrote:
>>>
>>> Hi, I'm sorry I haven't been watching this change.
>>>
>>> http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-04/src/hotspot/share/classfile/classLoaderData.cpp.udiff.html
>>>
>>> Can you move find_class() into systemDictionary.hpp/cpp with the rest of the find_class(). This is strange here. You don't want to expose that the dictionary is here to the rest of the code. The caller should call one of the SystemDictionary versions, or add this to SystemDictionary with the other functions with the same name.
>>>
>>> http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-04/src/hotspot/share/memory/lambdaFormInvokers.cpp.html
>>>
>>> These new files belongs in classfile. It's closer to systemDictionaryShared code than memory code.
>>>
>>> 2 * Copyright (c) 2012, 2020, Oracle and/or its affiliates. All rights reserved.
>>>
>>>
>>> Also copyright shouldn't start with 2012.
>>>
>>> http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-04/src/hotspot/share/classfile/systemDictionaryShared.cpp.udiff.html
>>>
>>> This add_to_hierarchy is a strange delegation and a surprise that it's also defined here. Please call this inline from lambdaFormInvokers, ie take the Compile_lock and call SystemDictionary::add_to_hierarchy().
>>>
>>> I don't have any deeper comments.
>>>
>>> Thanks,
>>> Coleen
>>>
>>> On 8/25/20 2:59 PM, Yumin Qi wrote:
>>>> HI, Ioi
>>>>
>>>> Thanks for the re-review, updated webrev:
>>>>
>>>> http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-04/
>>>>
>>>> Changed according to your suggestion, the only a little difference is move traceResolve(String line) to InvokerBytecodeGenerator as a static package public function so other package classes can call it.
>>>>
>>>> re-tested local on runtime/cds
>>>>
>>>>
>>>> Thanks
>>>>
>>>> Yumin
>>>>
>>>>
>>>> On 8/24/20 4:23 PM, Ioi Lam wrote:
>>>>> Hi Yumin,
>>>>>
>>>>> This looks good overall. Here are my comments:
>>>>>
>>>>> =====================
>>>>> 6065 size_t new_id = Atomic::add(&counter, (size_t)1);
>>>>> 6066 jio_snprintf(addr_buf, 20, INTPTR_FORMAT, new_id);
>>>>>
>>>>> I think this should be SIZE_FORMAT
>>>>>
>>>>> =====================
>>>>> 65 class KlassFactory : AllStatic {
>>>>> 66
>>>>> 67 // approved clients
>>>>> 68 friend class ClassLoader;
>>>>> 69 friend class ClassLoaderExt;
>>>>> 70 friend class SystemDictionary;
>>>>> 71 friend class LambdaFormInvokers;
>>>>> 72
>>>>> 73 private:
>>>>> 74 static InstanceKlass* create_from_stream(ClassFileStream* stream,
>>>>>
>>>>> I think instead of adding everyone who uses create_from_stream as a friend class, we should just change create_from_stream into a public function and remove the friend declarations.
>>>>>
>>>>> =====================
>>>>> 146 // add to hierarchy and set state to loaded.
>>>>> 147 {
>>>>> 148 MutexLocker mu_r(THREAD, Compile_lock); // add_shared_to_hierarchy asserts this.
>>>>> 149 SystemDictionaryShared::add_shared_to_hierarchy(result, THREAD);
>>>>> 150 }
>>>>>
>>>>> I think the function name can be changed to SystemDictionaryShared::add_to_hierarchy as the "_shared" seems redundant. The "set state to loaded" comment seems wrong, as we have the assert on line 1155. I think the comment can be removed.
>>>>>
>>>>> 1153 void SystemDictionaryShared::add_shared_to_hierarchy(InstanceKlass* k, TRAPS) {
>>>>> 1154 Arguments::assert_is_dumping_archive();
>>>>> 1155 assert(!k->is_loaded(), "Invariant");
>>>>> 1156 assert_locked_or_safepoint(Compile_lock); // add_to_hierarchy assert on it.
>>>>> 1157 SystemDictionary::add_to_hierarchy(k, CHECK);
>>>>> 1158 }
>>>>>
>>>>> Also, I think it's better to move the MutexLocker call into SystemDictionaryShared::add_shared_to_hierarchy.
>>>>>
>>>>> ========================
>>>>>
>>>>> before:
>>>>>
>>>>> 478 if (TRACE_RESOLVE && salvage != null) {
>>>>> 479 // Used by jlink species pregeneration plugin, see
>>>>> 480 // jdk.tools.jlink.internal.plugins.GenerateJLIClassesPlugin
>>>>> 481 System.out.println("[SPECIES_RESOLVE] " + className + " (salvaged)");
>>>>> 482 }
>>>>>
>>>>> after:
>>>>>
>>>>> 488 // Used by jlink species pregeneration plugin, see
>>>>> 489 // jdk.tools.jlink.internal.plugins.GenerateJLIClassesPlugin
>>>>> 490 traceResolve("[SPECIES_RESOLVE] " + className + " (salvaged)");
>>>>>
>>>>>
>>>>> When tracing is disabled, this will make extra allocations and cause a small slowdown. I think it's better to
>>>>>
>>>>> if ((TRACE_RESOLVE|TRACE_RESOLVE_CDS) && salvage != null) {
>>>>> traceResolve("[SPECIES_RESOLVE] " + className + " (salvaged)");
>>>>> }
>>>>>
>>>>> Because TRACE_RESOLVE is a static final boolean, the JIT compiler will completely optimize this block out.
>>>>>
>>>>> For the same reason, instead of calling VM.isDumpLoadedClassListSetAndOpen() every time, it's better to use a static final variable.
>>>>>
>>>>>
>>>>> =======================
>>>>>
>>>>> 698 if (TRACE_RESOLVE) {
>>>>> 699 System.out.println("[LF_RESOLVE] " + holder.getName() + " " + name + " " +
>>>>> 700 shortenSignature(basicTypeSignature(type)) + (resolvedMember != null ? " (success)" : " (fail)") );
>>>>> 701 }
>>>>> 702 if (VM.isDumpLoadedClassListSetAndOpen()) {
>>>>> 703 GenerateJLIClassesHelper.cdsTraceResolve("[LF_RESOLVE] " + holder.getName() + " " + name + " " +
>>>>> 704 shortenSignature(basicTypeSignature(type)) + (resolvedMember != null ? " (success)" : " (fail)") );
>>>>> 705 }
>>>>> 706 return resolvedMember;
>>>>>
>>>>>
>>>>> I think the two "if" blocks should be combined similarly to ClassSpecializer::traceResolve().
>>>>>
>>>>> =========================
>>>>> 34 Java_java_lang_invoke_GenerateJLIClassesHelper_cdsTraceResolve(JNIEnv *env, jclass ignore, jstring line) {
>>>>>
>>>>> Maybe this should be moved to the "VM" class as well?
>>>>>
>>>>> =========================
>>>>> lambdaFormInvokers.hpp:
>>>>>
>>>>> Need these declarations:
>>>>>
>>>>> #include "memory/allocation.hpp" <-- for AllStatic
>>>>> #include "runtime/handles.hpp" <-- for typeArrayHandle and Handle
>>>>> #include "utilities/exceptions.hpp" <-- for TRAPS
>>>>>
>>>>> template <class T> class GrowableArray;
>>>>> =========================
>>>>>
>>>>>
>>>>> Thanks
>>>>> - Ioi
>>>>>
>>>>>
>>>>>
>>>>> On 8/23/20 3:56 PM, Yumin Qi wrote:
>>>>>>
>>>>>> Hi, Mandy, Ioi and Calvin
>>>>>>
>>>>>>
>>>>>> I have updated the new changed at:
>>>>>>
>>>>>> http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-03/
>>>>>>
>>>>>> In this version:
>>>>>>
>>>>>> 1) Added a new API to check if flag DumpLoadedClassList set and the file is open. If true, call into vm to print out the trace line to the log file.
>>>>>>
>>>>>> Just thinking if we just call the cdsTraceResolve without checking if the flag DumpLoadedClassList set and file open, this way, the check logic is in the vm side like before, so save code by not adding the new API.
>>>>>>
>>>>>> 2) The returned holder class names now are just 'package/className', removed head and tail.
>>>>>>
>>>>>> 3) Remove add_extra_classes from CollectClassesClosure since after bug 8250990: https://bugs.openjdk.java.net/browse/JDK-8250990 pushed, the CollectClassesClosure no longer exist.
>>>>>>
>>>>>> 4) Still keep the parsing for TRACE_RESOLVE in java/lang/invoke/GenerateJLIClassesHelper.java, so VM call its function to regenerate holder classes.
>>>>>>
>>>>>>
>>>>>> Re-tested Mach5 tier1-4
>>>>>>
>>>>>> Thanks
>>>>>>
>>>>>> Yumin
>>>>>>
>>>>>>
>>>>>> On 8/20/20 8:05 PM, Yumin Qi wrote:
>>>>>>> Hi, Mandy
>>>>>>>
>>>>>>>
>>>>>>> On 8/20/20 5:10 PM, Mandy Chung wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> On 8/19/20 10:14 PM, Yumin Qi wrote:
>>>>>>>>>
>>>>>>>>> HI, Mandy
>>>>>>>>>
>>>>>>>>> Thanks for the review, I took one day off yesterday so just got a detail look of your reply.
>>>>>>>>>
>>>>>>>>> On 8/19/20 1:30 PM, Mandy Chung wrote:
>>>>>>>>>> On 8/17/20 12:37 PM, Yumin Qi wrote:
>>>>>>>>>>> Hi, Ioi
>>>>>>>>>>>
>>>>>>>>>>> Thanks for review/suggestion. I have updated the webrev at the following link:
>>>>>>>>>>>
>>>>>>>>>>> http://cr.openjdk.java.net/~minqi/2020/8247536/webrev-02/
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> This patch leverages the TRACE_RESOLVE output and passes the trace output to VM. VM then calls GenerateJLIClassesHelper::generateMHHolderClasses to do the parsing and generate Holder class per the resolved LFs. I think there are other cleaner alternatives implementing this. jlink --generate-jli-classes plugin depends the trace output whereas -Xshare:dump does not. It's cleaner to skip generating the trace output and parsing for dumping shared archive purpose. In addition, the implementation needs some cleanup (I can send you feedback on the next revision)
>>>>>>>>>>
>>>>>>>>> Current patch did not change the existing code for JLinkPlugin part. I just moved the parsing code from GenerateJLIClassesPlugin.java to GenerateJLIClassesHelper.java since the former is an internal class to which we shouldn't call to generate holder classes.
>>>>>>>>>> Instead of relying on a system property "java.lang.invoke.MethodHandle.CDS_TRACE_RESOLVE", it's better to use jdk.internal.vm.isCDSDumpingEnabled() to detect if this is CDS dump time.
>>>>>>>>>
>>>>>>>>> I remember we have such API to query if flag -Xshare:dump or -Xshare:on used. Do you mean if DumpLoadedClassList flag set? This flag is the one used to log class name to list file. In GenerateLinkOptData.gmk:
>>>>>>>>>
>>>>>>>>> $(CLASSLIST_FILE): $(INTERIM_IMAGE_DIR)/bin/java$(EXE_SUFFIX) $(CLASSLIST_JAR)
>>>>>>>>> $(call MakeDir, $(LINK_OPT_DIR))
>>>>>>>>> $(call LogInfo, Generating $(patsubst $(OUTPUTDIR)/%, %, $@))
>>>>>>>>> $(call LogInfo, Generating $(patsubst $(OUTPUTDIR)/%, %, $(JLI_TRACE_FILE)))
>>>>>>>>> $(FIXPATH) $(INTERIM_IMAGE_DIR)/bin/java -XX:DumpLoadedClassList=$@.raw \
>>>>>>>>> -Duser.language=en -Duser.country=US \
>>>>>>>>> -cp $(SUPPORT_OUTPUTDIR)/classlist.jar \
>>>>>>>>> build.tools.classlist.HelloClasslist $(LOG_DEBUG)
>>>>>>>>> $(GREP) -v HelloClasslist $@.raw > $@.interim
>>>>>>>>> $(FIXPATH) $(INTERIM_IMAGE_DIR)/bin/java -Xshare:dump \
>>>>>>>>> -XX:SharedClassListFile=$@.interim -XX:SharedArchiveFile=$@.jsa \
>>>>>>>>> -Xmx128M -Xms128M $(LOG_INFO)
>>>>>>>>> $(FIXPATH) $(INTERIM_IMAGE_DIR)/bin/java -XX:DumpLoadedClassList=$@.raw.2 \
>>>>>>>>> -XX:SharedClassListFile=$@.interim -XX:SharedArchiveFile=$@.jsa \
>>>>>>>>> -Djava.lang.invoke.MethodHandle.TRACE_RESOLVE=true \
>>>>>>>>> -Duser.language=en -Duser.country=US \
>>>>>>>>> --module-path $(SUPPORT_OUTPUTDIR)/classlist.jar \
>>>>>>>>> -cp $(SUPPORT_OUTPUTDIR)/classlist.jar \
>>>>>>>>> build.tools.classlist.HelloClasslist \
>>>>>>>>> 2> $(LINK_OPT_DIR)/stderr > $(JLI_TRACE_FILE) \
>>>>>>>>> || ( \
>>>>>>>>> exitcode=$$? ; \
>>>>>>>>> $(ECHO) "ERROR: Failed to generate link optimization data." \
>>>>>>>>> "This is likely a problem with the newly built JVM/JDK." ; \
>>>>>>>>> $(CAT) $(LINK_OPT_DIR)/stderr $(JLI_TRACE_FILE) ; \
>>>>>>>>> exit $$exitcode \
>>>>>>>>> )
>>>>>>>>> $(GREP) -v HelloClasslist $@.raw.2 > $@
>>>>>>>>>
>>>>>>>>> The $(JLI_TRACE_FILE) is generated with both -XX:DumpLoadedClassList and -Djava.lang.invoke.MethodHandle.TRACE_RESOLVE=true, in current implementation, DumpLoadedClassList will turn on property java.lang.invoke.MethodHandle.CDS_TRACE_RESOLVE=true. So the same output sent to stdout and log file DumpLoadedClassList specified.
>>>>>>>>>
>>>>>>>>
>>>>>>>> These entries are duplicated in two different files: one for jlink --generate-jli-classes plugin and another for CDS use. CDS -Xshare:dump attempts to do what jlink plugin does but writes those generated classes in to shared archive.
>>>>>>>>
>>>>>>>> Like the above make logic to build JDK image, the same entries are written in both default-jli-trace.txt via System.out and to classlist via JNI call to the VM. I guess VM also implements the logic to do some kind of diffing and write to CDS archive.
>>>>>>>>
>>>>>>> In current implementation, vm side only records the line as from TRACE_RESOLVE at pre-run with -XX:DumpLoadedClassList, and at dump time, call back to java for parsing those recordings and generating the holder classes, this uses the existing JLI code.
>>>>>>>>>
>>>>>>>>> Now instead of this property, using a vm interface API to query if this flag is set, I think it is better choice. But here I am NOT sure I understand your suggestion, I think there are two choices:
>>>>>>>>>
>>>>>>>>> 1) Using DumpLoadedClassList to collect TRACE_RESOLVE but not via CDS_TRACE_RESOLVE, using new API to query if DumpLoadedClassList is set
>>>>>>>>>
>>>>>>>>> 2) Do not use DumpLoadedClassList, when -Xshare:dump collecting those name, type and holder name to regenerate holder classes?
>>>>>>>>>
>>>>>>>>
>>>>>>>> I misunderstood that this CDS_TRACE_RESOLVE flag is set during -Xshare:dump time.
>>>>>>>>
>>>>>>>> Ioi has clarified to me offline that this step is actually part of -XX:DumpLoadedClassList and includes these TRACE_RESOLVE logs to the given class list file, i.e. you repurpose the class list file to include the log output that was initially designed for jlink plugin.
>>>>>>>>
>>>>>>>> To me, I'd prefer to see this support depending on `jlink --generate-jli-classes` which is an existing functionality and much cleaner. This way this does not require any VM change. It will generate the holder classes in the custom image per the application-specific config file.
>>>>>>>>
>>>>>>>> What it means is that: a customer would need to create a custom image with their application-specific config file. It might need a new CDS option to specify a separate TRACE_RESOLVE file. It would turn on this feature by default by defining a default path of the log file if it helps.
>>>>>>>>
>>>>>>> So for now, I would implement an API to query if flag DumpLoadedClassList set in cmd line, remove new added property of java.lang.invoke.MethodHandle.CDS_TRACE_RESOLVE. We can address custom image with CDS in future in a separate issue.
>>>>>>>
>>>>>>>
>>>>>>> Thanks
>>>>>>>
>>>>>>> Yumin
>>>>>>>
>>>>>>>> I understand that this is not the existing CDS work flow and CDS archive does not require to run on a custom image. I see the value of this approach which can prepare customers to start building and using its own custom image.
>>>>>>>>
>>>>>>>> Of course the implementation would be much simpler (adding a flag to write these traces to a given file path, that is).
>>>>>>>>
>>>>>>>> Mandy
>>>>>
>>>
>
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