RFR (L, tedious again, sorry) 8189610: Reconcile jvm.h and all jvm_md.h between java.base and hotspot
David Holmes
david.holmes at oracle.com
Tue Oct 31 00:21:45 UTC 2017
On 31/10/2017 12:48 AM, coleen.phillimore at oracle.com wrote:
>
> http://cr.openjdk.java.net/~coleenp/8189610.incr.02/webrev/index.html
>
> Changed JDK file to use PATH_MAX. Retested jdk tier1 tests.
Why PATH_MAX instead of MAXPATHLEN? They appear to be the same on Linux
and Solaris, but I don't know if that is true for AIX and Mac OS / BSD.
Does UnixFileSystem_md.c still need the jvm.h include now?
Thanks,
David
> thanks,
> Coleen
>
> On 10/30/17 8:38 AM, coleen.phillimore at oracle.com wrote:
>>
>>
>> On 10/30/17 8:17 AM, David Holmes wrote:
>>> On 30/10/2017 10:13 PM, coleen.phillimore at oracle.com wrote:
>>>> On 10/28/17 3:50 AM, David Holmes wrote:
>>>>> Hi Coleen,
>>>>>
>>>>> I've commented on the file location in response to Mandy's email.
>>>>>
>>>>> The only issue I'm still concerned about is the JVM_MAXPATHLEN
>>>>> issue. I think it is a bug to define a JVM_MAXPATHLEN that is
>>>>> bigger than the platform MAXPATHLEN. I also would not want to see
>>>>> any change in behaviour because of this - so AIX and Solaris should
>>>>> not get a different JVM_MAXPATHLEN due to this refactoring change.
>>>>> So yes I think this needs to be ifdef'd for Linux and reluctantly
>>>>> (because it was a copy error) for OSX/BSD as well.
>>>>
>>>> #if defined(AIX) || defined(SOLARIS)
>>>> #define JVM_MAXPATHLEN MAXPATHLEN
>>>> #else
>>>> // Hack: MAXPATHLEN is 4095 on some Linux and 4096 on others. This may
>>>> // cause problems if JVM and the rest of JDK are built on
>>>> different
>>>> // Linux releases. Here we define JVM_MAXPATHLEN to be
>>>> MAXPATHLEN + 1,
>>>> // so buffers declared in VM are always >= 4096.
>>>> #define JVM_MAXPATHLEN MAXPATHLEN + 1
>>>> #endif
>>>>
>>>> Is this ok?
>>>
>>> Yes - thanks. It preserves existing behaviour on the VM side at
>>> least. Time will tell if it messes anything up on the JDK side for
>>> Linux/OSX.
>>
>> I don't want to wait for time so I'm investigating.
>>
>> It's one use is:
>>
>> Java_java_io_UnixFileSystem_canonicalize0(JNIEnv *env, jobject this,
>> ...
>> char canonicalPath[JVM_MAXPATHLEN];
>> if (canonicalize((char *)path,
>> canonicalPath, JVM_MAXPATHLEN) < 0) {
>> JNU_ThrowIOExceptionWithLastError(env, "Bad pathname");
>>
>> Which goes to:
>>
>> canonicalize_md.c
>>
>> canonicalize(char *original, char *resolved, int len)
>> if (len < PATH_MAX) {
>> errno = EINVAL;
>> return -1;
>> }
>>
>>
>> So this should fail every time.
>>
>> sys/param.h:# define MAXPATHLEN PATH_MAX
>>
>> I haven't found any tests for it.
>>
>> I don't know why Java_java_io_UnixFileSystem uses JVM_MAXPATHLEN since
>> it's not calling the JVM interface as far as I can tell. I think it
>> should be changed to PATH_MAX.
>>
>> ?
>> Coleen
>>>
>>> David
>>>
>>>> thanks,
>>>> Coleen
>>>>>
>>>>> Thanks,
>>>>> David
>>>>>
>>>>> On 28/10/2017 12:08 AM, coleen.phillimore at oracle.com wrote:
>>>>>>
>>>>>>
>>>>>> On 10/27/17 9:37 AM, David Holmes wrote:
>>>>>>> On 27/10/2017 10:13 PM, coleen.phillimore at oracle.com wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> On 10/27/17 3:23 AM, David Holmes wrote:
>>>>>>>>> Hi Coleen,
>>>>>>>>>
>>>>>>>>> Thanks for tackling this.
>>>>>>>>>
>>>>>>>>>> Summary: removed hotspot version of jvm*h and jni*h files
>>>>>>>>>
>>>>>>>>> Can you update the bug synopsis to show it covers both sets of
>>>>>>>>> files please.
>>>>>>>>>
>>>>>>>>> I hate to start with this (and it took me quite a while to
>>>>>>>>> realize it) but as Mandy pointed out jvm.h is not an exported
>>>>>>>>> interface from the JDK to the outside world (so not subject to
>>>>>>>>> CSR review), but is a private interface between the JVM and the
>>>>>>>>> JDK libraries. So I think really jvm.h belongs in the hotspot
>>>>>>>>> sources where it was, while jni.h belongs in the exported JDK
>>>>>>>>> sources. In which case the bulk of your changes to the hotspot
>>>>>>>>> files would not be needed - sorry.
>>>>>>>>
>>>>>>>> Maybe someone can make that decision and change at a later date.
>>>>>>>> The point of this change is that there is now only one of these
>>>>>>>> files that is shared. I don't think jvm.h and the jvm_md.h
>>>>>>>> belong on the hotspot sources for the jdk to find them in some
>>>>>>>> random prims and os dependent directories.
>>>>>>>
>>>>>>> The one file that is needed is a hotspot file - jvm.h defines the
>>>>>>> interface that hotspot exports via jvm.cpp.
>>>>>>>
>>>>>>> If you leave jvm.h in hotspot/prims then a very large chunk of
>>>>>>> your boilerplate changes are not needed. The JDK code doesn't
>>>>>>> care what the name of the directory is - whatever it is just gets
>>>>>>> added as a -I directive (the JDK code will include "jvm.h" not
>>>>>>> "prims/jvm.h" the way hotspot sources do.
>>>>>>>
>>>>>>> This isn't something we want to change back or move again later.
>>>>>>> Whatever we do now we live with.
>>>>>>
>>>>>> I think it belongs with jni.h and I think the core libraries group
>>>>>> would agree. It seems more natural there than buried in the
>>>>>> hotspot prims directory. I guess this is on hold while we have
>>>>>> this debate. Sigh.
>>>>>>
>>>>>> Actually with -I directives, changing to jvm.h from prims/jvm.h
>>>>>> would still work. Maybe we should change the name to jvm.hpp
>>>>>> since it's jvm.cpp though? Or maybe just have two divergent
>>>>>> copies and close this as WNF.
>>>>>>
>>>>>>>
>>>>>>>> I'm happy to withdraw the CSR. We generally use the CSR process
>>>>>>>> to add and remove JVM_ interfaces even though they're a private
>>>>>>>> interface in case some other JVM/JDK combination relies on them.
>>>>>>>> The changes to these files are very minor though and not likely
>>>>>>>> to cause any even theoretical incompatibility, so I'll withdraw it.
>>>>>>>>>
>>>>>>>>> Moving on ...
>>>>>>>>>
>>>>>>>>> First to address the initial comments/query you had:
>>>>>>>>>
>>>>>>>>>> The JDK windows jni_md.h file defined jint as long and the
>>>>>>>>>> hotspot
>>>>>>>>>> windows jni_x86.h as int. I had to choose the jdk version
>>>>>>>>>> since it's the
>>>>>>>>>> public version, so there are changes to the hotspot files for
>>>>>>>>>> this.
>>>>>>>>>
>>>>>>>>> On Windows int and long are always the same as it uses ILP32 or
>>>>>>>>> LLP64 (not LP64 like *nix platforms). So either choice should
>>>>>>>>> be fine. That said there are some odd casting issues I comment
>>>>>>>>> on below. Does the VS compiler complain about mixing int and
>>>>>>>>> long in expressions?
>>>>>>>>
>>>>>>>> Yes, it does even though int and long are the same representation.
>>>>>>>
>>>>>>> And what an absolute mess that makes. :(
>>>>>>>
>>>>>>>>>
>>>>>>>>>> Generally I changed the code to use 'int' rather than 'jint'
>>>>>>>>>> where the
>>>>>>>>>> surrounding API didn't insist on consistently using java
>>>>>>>>>> types. We
>>>>>>>>>> should mostly be using C++ types within hotspot except in
>>>>>>>>>> interfaces to
>>>>>>>>>> native/JNI code.
>>>>>>>>>
>>>>>>>>> I think you pulled too hard on a few threads here and things
>>>>>>>>> are starting to unravel. There are numerous cases I refer to
>>>>>>>>> below where either the cast seems unnecessary/inappropriate or
>>>>>>>>> else highlights a bunch of additional changes that also need to
>>>>>>>>> be made. The fan out from this could be horrendous. Unless you
>>>>>>>>> actually get some kind of error - and I'd like to understand
>>>>>>>>> the details of those - I would not suggest making these changes
>>>>>>>>> as part of this work.
>>>>>>>>
>>>>>>>> I didn't make any change unless there was was an error. I have
>>>>>>>> 100 failed JPRT jobs to confirm! I eventually got a Windows
>>>>>>>> system to compile and test this on. Actually some of the changes
>>>>>>>> came out better. Cases where we use jint as a bool simply
>>>>>>>> turned to int. We do not have an overload for bool for cmpxchg.
>>>>>>>
>>>>>>> That's unfortunate - ditto for OrderAccess.
>>>>>>>
>>>>>>>>>
>>>>>>>>> Looking through I have a quite a few queries/comments -
>>>>>>>>> apologies in advance as I know how tedious this is:
>>>>>>>>>
>>>>>>>>> make/hotspot/lib/CompileLibjsig.gmk
>>>>>>>>> src/java.base/solaris/native/libjsig/jsig.c
>>>>>>>>>
>>>>>>>>> Took a while to figure out why the include was needed. :) As a
>>>>>>>>> follow up I suggest just deleting the -I include directive,
>>>>>>>>> delete the Solaris-only definition of JSIG_VERSION_1_4_1, and
>>>>>>>>> delete everything to do with JVM_get_libjsig_version. It is all
>>>>>>>>> obsolete.
>>>>>>>>
>>>>>>>> Can I patch up jsig in a separate RFE? I don't remember why
>>>>>>>> this broke so I simply moved JSIG #define. Is jsig obsolete?
>>>>>>>> Removing JVM_* definitions generally requires a CSR.
>>>>>>>
>>>>>>> I did say "As a follow up". jsig is not obsolete but the jsig
>>>>>>> versioning code, only used by Solaris, is.
>>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/cpu/arm/interp_masm_arm.cpp
>>>>>>>>>
>>>>>>>>> Why did you need to add the jvm.h include?
>>>>>>>>>
>>>>>>>>
>>>>>>>> tbz(Raccess_flags, JVM_ACC_SYNCHRONIZED_BIT, unlocked);
>>>>>>>
>>>>>>> Okay. I'm not going to try and figure out how this code found
>>>>>>> this before.
>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/os/windows/os_windows.cpp.
>>>>>>>>>
>>>>>>>>> The type of process_exiting should be uint to match the DWORD
>>>>>>>>> of GetCurrentThreadID. Then you should need any casts. Also you
>>>>>>>>> missed this jint cast:
>>>>>>>>>
>>>>>>>>> 3796 process_exiting != (jint)GetCurrentThreadId()) {
>>>>>>>>
>>>>>>>> Yes, that's better to change process_exiting to a DWORD. It
>>>>>>>> needs a DWORD cast to 0 in the cmpxchg.
>>>>>>>>
>>>>>>>> Atomic::cmpxchg(GetCurrentThreadId(), &process_exiting,
>>>>>>>> (DWORD)0);
>>>>>>>>
>>>>>>>> These templates are picky.
>>>>>>>
>>>>>>> Yes - their inability to deal with literals is extremely
>>>>>>> frustrating.
>>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/c1/c1_Canonicalizer.hpp
>>>>>>>>>
>>>>>>>>> 43 #ifdef _WINDOWS
>>>>>>>>> 44 // jint is defined as long in jni_md.h, so convert from
>>>>>>>>> int to jint
>>>>>>>>> 45 void set_constant(int x) { set_constant((jint)x); }
>>>>>>>>> 46 #endif
>>>>>>>>>
>>>>>>>>> Why is this necessary? int and long are the same on Windows.
>>>>>>>>> The whole point is that jint hides the underlying type, so
>>>>>>>>> where does this go wrong?
>>>>>>>>
>>>>>>>> No, they are not the same types even though they have the same
>>>>>>>> representation!
>>>>>>>
>>>>>>> This is truly unfortunate.
>>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/c1/c1_LinearScan.cpp
>>>>>>>>>
>>>>>>>>> ConstantIntValue((jint)0);
>>>>>>>>>
>>>>>>>>> why is this cast needed? what causes the ambiguity? (If this
>>>>>>>>> was a template I'd understand ;-) ). Also didn't you change
>>>>>>>>> that constructor to take an int anyway - not that I think it
>>>>>>>>> should - see below.
>>>>>>>>
>>>>>>>> Yes, it caused an ambiguity. 0 matches 'int' but it doesn't
>>>>>>>> match 'long' better than any pointer type. So this cast is needed.
>>>>>>>
>>>>>>> But you changed the constructor to take an int!
>>>>>>>
>>>>>>> class ConstantIntValue: public ScopeValue {
>>>>>>> private:
>>>>>>> - jint _value;
>>>>>>> + int _value;
>>>>>>> public:
>>>>>>> - ConstantIntValue(jint value) { _value = value; }
>>>>>>> + ConstantIntValue(int value) { _value = value; }
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> Okay I removed this cast.
>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/ci/ciReplay.cpp
>>>>>>>>>
>>>>>>>>> 793 jint* dims = NEW_RESOURCE_ARRAY(jint, rank);
>>>>>>>>>
>>>>>>>>> why should this be jint?
>>>>>>>>
>>>>>>>> To avoid a cast from int* to jint* in the line below:
>>>>>>>>
>>>>>>>> value = kelem->multi_allocate(rank, dims, CHECK);
>>>>>>>>
>>>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/classfile/altHashing.cpp
>>>>>>>>>
>>>>>>>>> Okay this looks more consistent with jint.
>>>>>>>>
>>>>>>>> Yes. I translated this from some native code iirc.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/code/debugInfo.hpp
>>>>>>>>>
>>>>>>>>> These changes seem wrong. We have:
>>>>>>>>>
>>>>>>>>> ConstantLongValue(jlong value)
>>>>>>>>> ConstantDoubleValue(jdouble value)
>>>>>>>>>
>>>>>>>>> so we should have:
>>>>>>>>>
>>>>>>>>> ConstantIntValue(jint value)
>>>>>>>>
>>>>>>>> Again, there are multiple call sites with '0', which match int
>>>>>>>> trivially but are confused with long. It's less consistent I
>>>>>>>> agree but better to not cast all the call sites.
>>>>>>>
>>>>>>> This is really making a mess of the APIs - they should be a jint
>>>>>>> but we declare them int because of a 0 casting problem. Can't we
>>>>>>> just use 0L?
>>>>>>
>>>>>> There aren't that many casts. You're right, that would have been
>>>>>> better in some places.
>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/code/relocInfo.cpp
>>>>>>>>>
>>>>>>>>> Change seems unnecessary - int32_t is fine
>>>>>>>>>
>>>>>>>>
>>>>>>>> No, int32_t doesn't match the calls below it. They all assume
>>>>>>>> _lo and _hi are jint.
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/compiler/compileBroker.cpp
>>>>>>>>> src/hotspot/share/compiler/compileBroker.hpp
>>>>>>>>>
>>>>>>>>> I see a complete mix of int and jint in this class, so why make
>>>>>>>>> the one change you did ??
>>>>>>>>
>>>>>>>> This is another case of using jint as a flag with cmpxchg. The
>>>>>>>> templates for cmpxchg want the types to match and 0 and 1 are
>>>>>>>> essentially 'int'. This is a lot cleaner this way.
>>>>>>>
>>>>>>> <sigh>
>>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/jvmci/jvmciCompilerToVM.cpp
>>>>>>>>>
>>>>>>>>> 1700 tty->write((char*) start, MIN2(length, (jint)O_BUFLEN));
>>>>>>>>>
>>>>>>>>> why did you need to add the jint cast? It's used without any
>>>>>>>>> cast on the next two lines:
>>>>>>>>>
>>>>>>>>> 1701 length -= O_BUFLEN;
>>>>>>>>> 1702 offset += O_BUFLEN;
>>>>>>>>>
>>>>>>>>
>>>>>>>> There's a conversion from O_BUFLEN from int to long in 1701 and
>>>>>>>> 1702. MIN2 is a template that wants the types to match exactly.
>>>>>>>
>>>>>>> $%^%$! templates!
>>>>>>>
>>>>>>>>> ??
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/jvmci/jvmciRuntime.cpp
>>>>>>>>>
>>>>>>>>> Looking around this code it seems very confused about types -
>>>>>>>>> eg the previous function is declared jboolean yet returns a
>>>>>>>>> jint on one path! It isn't clear to me if the return type is
>>>>>>>>> what should be changed or the parameter type? I would just
>>>>>>>>> leave this alone.
>>>>>>>>
>>>>>>>> I can't leave it alone because it doesn't compile that way. This
>>>>>>>> was the minimal change and yea, does look a bit inconsistent.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/opto/mulnode.cpp
>>>>>>>>>
>>>>>>>>> Okay TypeInt has jint parts, so the remaining int32_t
>>>>>>>>> declarations (A, B, C, D) should also be jint.
>>>>>>>>
>>>>>>>> Yes. c2 uses jint types.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/opto/parse3.cpp
>>>>>>>>>
>>>>>>>>> I agree with the changes you made, but then:
>>>>>>>>>
>>>>>>>>> 419 jint dim_con = find_int_con(length[j], -1);
>>>>>>>>>
>>>>>>>>> should also be changed.
>>>>>>>>>
>>>>>>>>> And obviously MultiArrayExpandLimit should be defined as int
>>>>>>>>> not intx!
>>>>>>>>
>>>>>>>> Everything in globals.hpp is intx. That's a thread that I don't
>>>>>>>> want to pull on!
>>>>>>>
>>>>>>> We still have that limitation? <double sigh>
>>>>>>>>
>>>>>>>> Changed dim_con to int.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/opto/phaseX.cpp
>>>>>>>>>
>>>>>>>>> I can see that intcon(jint i) is consistent with longcon(jlong
>>>>>>>>> l), but the use of "i" in the code is more consistent with int
>>>>>>>>> than jint.
>>>>>>>>
>>>>>>>> huh? really?
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/opto/type.cpp
>>>>>>>>>
>>>>>>>>> 1505 int TypeInt::hash(void) const {
>>>>>>>>> 1506 return java_add(java_add(_lo, _hi),
>>>>>>>>> java_add((jint)_widen, (jint)Type::Int));
>>>>>>>>> 1507 }
>>>>>>>>>
>>>>>>>>> I can see that the (jint) casts you added make sense, but then
>>>>>>>>> the whole function should be returning jint not int. Ditto the
>>>>>>>>> other hash functions.
>>>>>>>>
>>>>>>>> I'm not messing with this, this is the minimal in type fixing
>>>>>>>> that I'm going to do here.
>>>>>>>
>>>>>>> <sigh>
>>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/prims/jni.cpp
>>>>>>>>>
>>>>>>>>> I think vm_created should be a bool. In fact all the fields you
>>>>>>>>> changed are logically bools - do Atomics work for bool now?
>>>>>>>>
>>>>>>>> No, they do not. I had thought bool would be better originally
>>>>>>>> too.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/prims/jvm.cpp
>>>>>>>>>
>>>>>>>>> is_attachable is the terminology used in the JDK code.
>>>>>>>>
>>>>>>>> Well the JDK version had is_attach_supported() as the flag name
>>>>>>>> so I used that in this one place.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/prims/jvmtiEnvBase.cpp
>>>>>>>>> src/hotspot/share/prims/jvmtiImpl.cpp
>>>>>>>>>
>>>>>>>>> Are you making parameters consistent with the fields they
>>>>>>>>> initialize?
>>>>>>>>
>>>>>>>> They're consistent with the declarations now.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/prims/jvmtiTagMap.cpp
>>>>>>>>>
>>>>>>>>> There is a mix of int and jint for slot in this code. You fixed
>>>>>>>>> some, but this remains:
>>>>>>>>>
>>>>>>>>> 2440 inline bool CallbackInvoker::report_stack_ref_root(jlong
>>>>>>>>> thread_tag,
>>>>>>>>> 2441 jlong tid,
>>>>>>>>> 2442 jint depth,
>>>>>>>>> 2443 jmethodID method,
>>>>>>>>> 2444 jlocation bci,
>>>>>>>>> 2445 jint slot,
>>>>>>>>
>>>>>>>> Right for consistency with the declarations.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/runtime/perfData.cpp
>>>>>>>>>
>>>>>>>>> Callers pass both jint and int, so param type seems arbitrary.
>>>>>>>>
>>>>>>>> They are, but importantly they match the declarations.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/hotspot/share/runtime/perfMemory.cpp
>>>>>>>>> src/hotspot/share/runtime/perfMemory.hpp
>>>>>>>>>
>>>>>>>>> PerfMemory::_initialized should ideally be a bool - can
>>>>>>>>> OrderAccess handle that now?
>>>>>>>>
>>>>>>>> Nope.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/java.base/share/native/include/jvm.h
>>>>>>>>>
>>>>>>>>> Not clear why the jio functions are not also JNICALL ?
>>>>>>>>
>>>>>>>> They are now. The JDK version didn't have JNICALL. JVM needs
>>>>>>>> JNICALL. I can't tell you why JDK didn't need JNICALL linkage.
>>>>>>>
>>>>>>> ?? JVM currently does not have JNICALL. But they are declared as
>>>>>>> "extern C".
>>>>>>
>>>>>> This was a compilation error on Windows with JDK. Maybe the C
>>>>>> code in the JDK doesn't complain about linkage differences. I'll
>>>>>> have to go back and figure this out then.
>>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/java.base/unix/native/include/jni_md.h
>>>>>>>>>
>>>>>>>>> There is no need to special case ARM. The differences in the
>>>>>>>>> existing code were for LTO support and that is now irrelevant.
>>>>>>>>
>>>>>>>> See discussion with Magnus. We still build ARM for jdk10/hs so
>>>>>>>> I needed this conditional or of course I wouldn't have added
>>>>>>>> it. We can remove it with LTO support.
>>>>>>>
>>>>>>> Those builds are gone - this is obsolete. But yes all LTO can be
>>>>>>> removed later if you wish. Just trying to simplify things now.
>>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/java.base/unix/native/include/jvm_md.h
>>>>>>>>>
>>>>>>>>> I know you've just copied this across, but it seems wrong to me:
>>>>>>>>>
>>>>>>>>> 57 // Hack: MAXPATHLEN is 4095 on some Linux and 4096 on
>>>>>>>>> others. This may
>>>>>>>>> 58 // cause problems if JVM and the rest of JDK are
>>>>>>>>> built on different
>>>>>>>>> 59 // Linux releases. Here we define JVM_MAXPATHLEN to
>>>>>>>>> be MAXPATHLEN + 1,
>>>>>>>>> 60 // so buffers declared in VM are always >= 4096.
>>>>>>>>> 61 #define JVM_MAXPATHLEN MAXPATHLEN + 1
>>>>>>>>>
>>>>>>>>> It doesn't make sense to me to define an internal "max path
>>>>>>>>> length" that can _exceed_ the platform max!
>>>>>>>>>
>>>>>>>>> That aside there's no support for building different parts of
>>>>>>>>> the JDK on different platforms and then bringing them together.
>>>>>>>>> And in any case I would think the real problem would be
>>>>>>>>> building on a platform that uses 4096 and running on one that
>>>>>>>>> uses 4095!
>>>>>>>>>
>>>>>>>>> But that aside this is a Linux hack and should be guarded by
>>>>>>>>> ifdef LINUX. (I doubt BSD needs it, the bsd file is just a copy
>>>>>>>>> of the linux one - the JDK macosx version does the right
>>>>>>>>> thing). Solaris and AIX should stay as-is at MAXPATHLEN.
>>>>>>>>
>>>>>>>> All of the unix platforms had MAXPATHLEN+1. I'll leave it for
>>>>>>>> now and we can investigate that further.
>>>>>>>
>>>>>>> I see the following existing code:
>>>>>>>
>>>>>>> src/java.base/unix/native/include/jvm_md.h:
>>>>>>>
>>>>>>> #define JVM_MAXPATHLEN MAXPATHLEN
>>>>>>>
>>>>>>> src/java.base/macosx/native/include/jvm_md.h
>>>>>>>
>>>>>>> #define JVM_MAXPATHLEN MAXPATHLEN
>>>>>>>
>>>>>>> src/hotspot/os/aix/jvm_aix.h
>>>>>>>
>>>>>>> #define JVM_MAXPATHLEN MAXPATHLEN
>>>>>>>
>>>>>>> src/hotspot/os/bsd/jvm_bsd.h
>>>>>>>
>>>>>>> #define JVM_MAXPATHLEN MAXPATHLEN + 1 // blindly copied from
>>>>>>> Linux version
>>>>>>>
>>>>>>> src/hotspot/os/linux/jvm_linux.h
>>>>>>>
>>>>>>> #define JVM_MAXPATHLEN MAXPATHLEN + 1
>>>>>>>
>>>>>>> src/hotspot/os/solaris/jvm_solaris.h
>>>>>>>
>>>>>>> #define JVM_MAXPATHLEN MAXPATHLEN
>>>>>>>
>>>>>>> This is a linux only hack (if you ignore the blind copy from
>>>>>>> linux into the BSD code in the VM).
>>>>>>
>>>>>> Oh, thanks, so should I add a bunch of ifdefs then? Or do you
>>>>>> think having MAXPATHLEN + 1 will really break the other
>>>>>> platforms? Do you really see this as a problem or are you just
>>>>>> pointing out inconsistency?
>>>>>>>
>>>>>>>>>
>>>>>>>>> 86 #define ASYNC_SIGNAL SIGJVM2
>>>>>>>>>
>>>>>>>>> This only exists on Solaris so I think should be in #ifdef
>>>>>>>>> SOLARIS, to make that clear.
>>>>>>>>
>>>>>>>> Ok. I'll add this.
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> src/java.base/windows/native/include/jvm_md.h
>>>>>>>>>
>>>>>>>>> Given the differences between the two versions either something
>>>>>>>>> has been broken or "extern C" declarations are not needed :)
>>>>>>>>
>>>>>>>> Well, they are needed for Hotspot to build and do not prevent
>>>>>>>> jdk from building. I don't know what was broken.
>>>>>>>
>>>>>>> We really need to understand this better. Maybe related to the
>>>>>>> map files that expose the symbols. ??
>>>>>>
>>>>>> They're needed because the JDK files are written mostly in C and
>>>>>> that doesn't complain about the linkage difference. Hotspot files
>>>>>> are in C++ which does complain.
>>>>>>
>>>>>>>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>>
>>>>>>>>> That was a really painful way to spend most of my Friday. TGIF! :)
>>>>>>>>
>>>>>>>> Thanks for going through it. See comments inline for changes.
>>>>>>>> Generating a webrev takes hours so I'm not going to do that
>>>>>>>> unless you insist.
>>>>>>>
>>>>>>> An incremental webrev shouldn't take long - right? You're a mq
>>>>>>> maestro now. :)
>>>>>>
>>>>>> Well I generally trash a repository whenever I use mq but sure.
>>>>>>>
>>>>>>> If you can reasonably produce an incremental webrev once you've
>>>>>>> settled on all the comments/issues that would be good.
>>>>>>
>>>>>> Ok, sure.
>>>>>>
>>>>>> Coleen
>>>>>>>
>>>>>>> Thanks,
>>>>>>> David
>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Coleen
>>>>>>>>
>>>>>>>>
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> David
>>>>>>>>> -----
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On 27/10/2017 6:44 AM, coleen.phillimore at oracle.com wrote:
>>>>>>>>>> Hi Magnus,
>>>>>>>>>>
>>>>>>>>>> Thank you for reviewing this. I have a new version that
>>>>>>>>>> takes out the hack in globalDefinitions.hpp and adds casts to
>>>>>>>>>> src/hotspot/share/opto/type.cpp instead.
>>>>>>>>>>
>>>>>>>>>> Also some fixes from Martin at SAP.
>>>>>>>>>>
>>>>>>>>>> open webrev at
>>>>>>>>>> http://cr.openjdk.java.net/~coleenp/8189610.02/webrev
>>>>>>>>>>
>>>>>>>>>> see below.
>>>>>>>>>>
>>>>>>>>>> On 10/26/17 5:57 AM, Magnus Ihse Bursie wrote:
>>>>>>>>>>> Coleen,
>>>>>>>>>>>
>>>>>>>>>>> Thank you for addressing this!
>>>>>>>>>>>
>>>>>>>>>>> On 2017-10-25 18:49, coleen.phillimore at oracle.com wrote:
>>>>>>>>>>>> Summary: removed hotspot version of jvm*h and jni*h files
>>>>>>>>>>>>
>>>>>>>>>>>> Mostly used sed to remove prims/jvm.h and move #include
>>>>>>>>>>>> "jvm.h" after precompiled.h, so if you have repetitive
>>>>>>>>>>>> stress wrist issues don't click on most of these files.
>>>>>>>>>>>>
>>>>>>>>>>>> There were more issues to resolve, however. The JDK windows
>>>>>>>>>>>> jni_md.h file defined jint as long and the hotspot windows
>>>>>>>>>>>> jni_x86.h as int. I had to choose the jdk version since it's
>>>>>>>>>>>> the public version, so there are changes to the hotspot
>>>>>>>>>>>> files for this. Generally I changed the code to use 'int'
>>>>>>>>>>>> rather than 'jint' where the surrounding API didn't insist
>>>>>>>>>>>> on consistently using java types. We should mostly be using
>>>>>>>>>>>> C++ types within hotspot except in interfaces to native/JNI
>>>>>>>>>>>> code. There are a couple of hacks in places where adding
>>>>>>>>>>>> multiple jint casts was too painful.
>>>>>>>>>>>>
>>>>>>>>>>>> Tested with JPRT and tier2-4 (in progress).
>>>>>>>>>>>>
>>>>>>>>>>>> open webrev at
>>>>>>>>>>>> http://cr.openjdk.java.net/~coleenp/8189610.01/webrev
>>>>>>>>>>>
>>>>>>>>>>> Looks great!
>>>>>>>>>>>
>>>>>>>>>>> Just a few comments:
>>>>>>>>>>>
>>>>>>>>>>> * src/java.base/unix/native/include/jni_md.h:
>>>>>>>>>>>
>>>>>>>>>>> I don't think the externally_visible attribute should be
>>>>>>>>>>> there for arm. I know this was the case for the corresponding
>>>>>>>>>>> hotspot file for arm, but that was techically incorrect. The
>>>>>>>>>>> proper dependency here is that externally_visible should be
>>>>>>>>>>> in all JNIEXPORT if and only if we're building with JVM
>>>>>>>>>>> feature "link-time-opt". Traditionally, that feature been
>>>>>>>>>>> enabled when building arm32 builds, and only then, so there's
>>>>>>>>>>> been a (coincidentally) connection here. Nowadays, Oracle
>>>>>>>>>>> does not care about the arm32 builds, and I'm not sure if
>>>>>>>>>>> anyone else is building them with link-time-opt enabled.
>>>>>>>>>>>
>>>>>>>>>>> It does seem wrong to me to export this behavior in the
>>>>>>>>>>> public jni_md.h file, though. I think the correct way to
>>>>>>>>>>> solve this, if we should continue supporting link-time-opt is
>>>>>>>>>>> to make sure this attribute is set for exported hotspot
>>>>>>>>>>> functions. If it's still needed, that is. A quick googling
>>>>>>>>>>> seems to indicate that visibility("default") might be enough
>>>>>>>>>>> in modern gcc's.
>>>>>>>>>>>
>>>>>>>>>>> A third option is to remove the support for link-time-opt
>>>>>>>>>>> entirely, if it's not really used.
>>>>>>>>>>
>>>>>>>>>> I didn't know how to change this since we are still building
>>>>>>>>>> ARM with the jdk10/hs repository, and ARM needed this change.
>>>>>>>>>> I could wait until we bring down the jdk10/master changes that
>>>>>>>>>> remove the ARM build and remove this conditional before I
>>>>>>>>>> push. Or we could file an RFE to remove link-time-opt (?) and
>>>>>>>>>> remove it then?
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> * src/java.base/unix/native/include/jvm_md.h and
>>>>>>>>>>> src/java.base/windows/native/include/jvm_md.h:
>>>>>>>>>>>
>>>>>>>>>>> These files define a public API, and contain non-trivial
>>>>>>>>>>> changes. I suspect you should file a CSR request. (Even
>>>>>>>>>>> though I realize you're only matching the header file with
>>>>>>>>>>> the reality.)
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> I filed the CSR. Waiting for the next steps.
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>> Coleen
>>>>>>>>>>
>>>>>>>>>>> /Magnus
>>>>>>>>>>>
>>>>>>>>>>>> bug link https://bugs.openjdk.java.net/browse/JDK-8189610
>>>>>>>>>>>>
>>>>>>>>>>>> I have a script to update copyright files on commit.
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks to Magnus and ErikJ for the makefile changes.
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks,
>>>>>>>>>>>> Coleen
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>
>>>>>>
>>>>
>>
>
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