RFR (XL): 8152664 - Support non-continuous CodeBlobs in HotSpot
Dean Long
dean.long at oracle.com
Fri Apr 15 21:19:22 UTC 2016
On 4/15/2016 11:28 AM, Volker Simonis wrote:
> Hi,
>
> this one was a real puzzler :)
> But I finally found some quiet hours in the office today and came up
> with this rather simple solution:
>
> http://cr.openjdk.java.net/~simonis/webrevs/2016/8151956/
>
> First I've tried to only move the relocation handling out of the
> CodeBlob constructor into the derived constructors but that didn't
> work very well and was quite complicated. So finally, I've just moved
> the call to CodeBuffer::copy_code_and_locs_to() from the CodeBlob
> constructor into the nmethod and RuntimeBlob constructors
> respectively. I couldn't find a reason why we shouldn't do this. The
> change is minimal and makes the whole handling more robust. I've
> compiled and smoke tested with JVM 98 on Linux/x86_64, Linux/ppc64le
> and Solaris/SPARC.
>
> I will run some more tests on Monday, but it would be great if you
> (i.e. Andrew) could verify this fix on ARM and if you (i.e.
> Rickard/Dean) could run some of your internal tests.
Hi Volker. This looks like what I was trying to accomplish with my
patch, but I introduced a new function CodeBlob::initialize(), and I
called it too early (in CompiledMethod instead of nmethod).
> I'd also like to ask if I should submit an extra RFR for 8151956 with
> my fix or if we should close 8151956 and fix it as part of Rickard's
> change for 8152664. I'd be happy with both solutions :)
Either way is fine with me.
dl
> A nice weekend everybody,
> Volker
>
>
> On Wed, Apr 13, 2016 at 3:31 PM, Rickard Bäckman
> <rickard.backman at oracle.com> wrote:
>> Volker,
>>
>> yes, I didn't realize at first that the nmethod was casted to a
>> CompiledMethod before the call to consts_begin(). Otherwise it would
>> have used the non-virtual consts_begin of nmethod that didn't have any
>> virtual calls.
>>
>> The entire code chain and looking up itself from the CodeCache before
>> fully constructed seems quite problematic. Even before the changes I
>> made. Previous to my changes the calls would have succeeded but returned
>> header_begin() or this for all the consts_begin, consts_end, etc... ?
>>
>> /R
>>
>> On 04/11, Volker Simonis wrote:
>>> Rickard, Dean,
>>>
>>> I'm afraid all this hacks can not work. It doesn't help to make
>>> CompiledMethod::consts_begin() non-virtual and then calling a virtual
>>> function from it. The problem ist that at the point where you call
>>> consts_begin_v(), the vtable of 'this' is still the one of CodeBlob and
>>> this results in calling yet another arbitrary function:
>>>
>>> #0 CodeBlob::is_locked_by_vm (this=0x3fff607d0c10) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/codeBlob.hpp:168
>>> #1 0x00003fffb6e38048 in CompiledMethod::consts_begin
>>> (this=0x3fff607d0c10) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/compiledMethod.hpp:255
>>> #2 0x00003fffb758d658 in RelocIterator::initialize (this=0x3ffdfd3fc9a8,
>>> nm=0x3fff607d0c10, begin=0x3fff607d0fac "\001", limit=0x0) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/relocInfo.cpp:142
>>> #3 0x00003fffb6ace56c in RelocIterator::RelocIterator
>>> (this=0x3ffdfd3fc9a8, nm=0x3fff607d0c10, begin=0x3fff607d0fac "\001",
>>> limit=0x0) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/relocInfo.hpp:1378
>>> #4 0x00003fffb7591afc in trampoline_stub_Relocation::get_trampoline_for
>>> (call=0x3fff607d0fac "\001", code=0x3fff607d0c10) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/relocInfo.cpp:849
>>> #5 0x00003fffb741ba4c in NativeCall::get_trampoline (this=0x3fff607d0fac)
>>> at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/cpu/ppc/vm/nativeInst_ppc.cpp:146
>>> #6 0x00003fffb7596a34 in Relocation::pd_call_destination
>>> (this=0x3ffdfd3fcd10, orig_addr=0x3fff6033482c "\001") at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/cpu/ppc/vm/relocInfo_ppc.cpp:87
>>> #7 0x00003fffb758f71c in CallRelocation::fix_relocation_after_move
>>> (this=0x3ffdfd3fcd10, src=0x3ffdfd3fdbc0, dest=0x3ffdfd3fcdd8) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/relocInfo.cpp:506
>>> #8 0x00003fffb6c48914 in CodeBuffer::relocate_code_to
>>> (this=0x3ffdfd3fdbc0, dest=0x3ffdfd3fcdd8) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/asm/codeBuffer.cpp:812
>>> #9 0x00003fffb6c48480 in CodeBuffer::copy_code_to (this=0x3ffdfd3fdbc0,
>>> dest_blob=0x3fff607d0c10) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/asm/codeBuffer.cpp:748
>>> #10 0x00003fffb6c426ec in CodeBuffer::copy_code_and_locs_to
>>> (this=0x3ffdfd3fdbc0, blob=0x3fff607d0c10) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/asm/codeBuffer.hpp:607
>>> #11 0x00003fffb6c3f8b0 in CodeBlob::CodeBlob (this=0x3fff607d0c10,
>>> name=0x3fffb7a760f8 "nmethod", layout=..., cb=0x3ffdfd3fdbc0,
>>> frame_complete_offset=20, frame_size=14, oop_maps=0x3ffe0001ed00,
>>> caller_must_gc_arguments=false, subtype=8) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/codeBlob.cpp:117
>>> #12 0x00003fffb6ce5360 in CompiledMethod::CompiledMethod
>>> (this=0x3fff607d0c10, method=0x3ffe1ddce568, name=0x3fffb7a760f8 "nmethod",
>>> size=1768, header_size=392, cb=0x3ffdfd3fdbc0, frame_complete_offset=20,
>>> frame_size=14, oop_maps=0x3ffe0001ed00, caller_must_gc_arguments=false) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/compiledMethod.cpp:42
>>> #13 0x00003fffb7422198 in nmethod::nmethod (this=0x3fff607d0c10,
>>> method=0x3ffe1ddce568, nmethod_size=1768, compile_id=4, entry_bci=-1,
>>> offsets=0x3ffdfd3fdb98, orig_pc_offset=104, debug_info=0x3fffb03f2dc0,
>>> dependencies=0x3ffe0001ed70, code_buffer=0x3ffdfd3fdbc0, frame_size=14,
>>> oop_maps=0x3ffe0001ed00, handler_table=0x3ffdfd3fdb50,
>>> nul_chk_table=0x3ffdfd3fdb70, compiler=0x3fffb03d0cd0, comp_level=3) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/nmethod.cpp:706
>>> #14 0x00003fffb7421850 in nmethod::new_nmethod (method=..., compile_id=4,
>>> entry_bci=-1, offsets=0x3ffdfd3fdb98, orig_pc_offset=104,
>>> debug_info=0x3fffb03f2dc0, dependencies=0x3ffe0001ed70,
>>> code_buffer=0x3ffdfd3fdbc0, frame_size=14, oop_maps=0x3ffe0001ed00,
>>> handler_table=0x3ffdfd3fdb50, nul_chk_table=0x3ffdfd3fdb70,
>>> compiler=0x3fffb03d0cd0, comp_level=3) at
>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/nmethod.cpp:548
>>>
>>> I think we really need to rework this as proposed by Andrew in his last
>>> mail. I'm working on such a fix.
>>>
>>> Regards,
>>> Volker
>>>
>>>
>>> On Mon, Apr 11, 2016 at 1:55 PM, Rickard Bäckman <rickard.backman at oracle.com
>>>> wrote:
>>>> Volker,
>>>>
>>>> here is the patch if you want to try it.
>>>> http://cr.openjdk.java.net/~rbackman/8152664/virtual.patch
>>>>
>>>> /R
>>>>
>>>> On 04/11, Rickard Bäckman wrote:
>>>>> Volker,
>>>>>
>>>>> thanks for finding this issue.
>>>>>
>>>>> I think that maybe the easiest fix is as follows:
>>>>>
>>>>> create new virtual methods in CompiledMethod:
>>>>>
>>>>> virtual address stub_begin_v() = 0;
>>>>>
>>>>> make the now virtual stub_begin non-virtual like:
>>>>>
>>>>> address stub_begin() { return stub_begin_v(); }
>>>>>
>>>>> in nmethod we override the stub_begin() with the normal this + offset
>>>>> compuation and implement stub_begin_v() to call stub_begin().
>>>>>
>>>>> That will avoid all virtual calls in the case were we are not working on
>>>>> a CompiledMethod.
>>>>>
>>>>> It adds a couple of methods though. What do you think?
>>>>>
>>>>> /R
>>>>>
>>>>> On 04/08, Volker Simonis wrote:
>>>>>> Hi Rickard,
>>>>>>
>>>>>> I found the problem why your change crashes the VM on ppc (and I'm
>>>> pretty
>>>>>> sure it will also crash on ARM - @Andrew, maybe you can try it out?).
>>>> It is
>>>>>> caused by the following code in address NativeCall::get_trampoline()
>>>> which
>>>>>> is also present on arm64:
>>>>>>
>>>>>> address NativeCall::get_trampoline() {
>>>>>> address call_addr = addr_at(0);
>>>>>> CodeBlob *code = CodeCache::find_blob(call_addr);
>>>>>> ...
>>>>>> // If the codeBlob is not a nmethod, this is because we get here
>>>> from the
>>>>>> // CodeBlob constructor, which is called within the nmethod
>>>> constructor.
>>>>>> return trampoline_stub_Relocation::get_trampoline_for(call_addr,
>>>>>> (nmethod*)code);
>>>>>> }
>>>>>>
>>>>>> The comment explains the situation quite well: we're in the CodeBlob
>>>>>> constructor which was called by the CompiledMethod constructor which
>>>> was
>>>>>> called from the nmethod constructor:
>>>>>>
>>>>>> #3 0x00003fffb741b80c in NativeCall::get_trampoline
>>>> (this=0x3fff607d0fac)
>>>>>> at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/cpu/ppc/vm/nativeInst_ppc.cpp:146
>>>>>> #4 0x00003fffb7596914 in Relocation::pd_call_destination
>>>>>> (this=0x3ffdfe3fcc90, orig_addr=0x3fff603b8a2c "\001") at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/cpu/ppc/vm/relocInfo_ppc.cpp:87
>>>>>> #5 0x00003fffb758f5fc in CallRelocation::fix_relocation_after_move
>>>>>> (this=0x3ffdfe3fcc90, src=0x3ffdfe3fdb40, dest=0x3ffdfe3fcd58) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/relocInfo.cpp:506
>>>>>> #6 0x00003fffb6c48898 in CodeBuffer::relocate_code_to
>>>>>> (this=0x3ffdfe3fdb40, dest=0x3ffdfe3fcd58) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/asm/codeBuffer.cpp:812
>>>>>> #7 0x00003fffb6c48404 in CodeBuffer::copy_code_to
>>>> (this=0x3ffdfe3fdb40,
>>>>>> dest_blob=0x3fff607d0c10) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/asm/codeBuffer.cpp:748
>>>>>> #8 0x00003fffb6c42670 in CodeBuffer::copy_code_and_locs_to
>>>>>> (this=0x3ffdfe3fdb40, blob=0x3fff607d0c10) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/asm/codeBuffer.hpp:607
>>>>>> #9 0x00003fffb6c3f834 in CodeBlob::CodeBlob (this=0x3fff607d0c10,
>>>>>> name=0x3fffb7a75fd8 "nmethod", layout=..., cb=0x3ffdfe3fdb40,
>>>>>> frame_complete_offset=20, frame_size=14, oop_maps=0x3ffe00049620,
>>>>>> caller_must_gc_arguments=false, subtype=8) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/codeBlob.cpp:117
>>>>>> #10 0x00003fffb6ce52c8 in CompiledMethod::CompiledMethod
>>>>>> (this=0x3fff607d0c10, method=0x3ffe1ddce568, name=0x3fffb7a75fd8
>>>> "nmethod",
>>>>>> size=1768, header_size=392, cb=0x3ffdfe3fdb40,
>>>> frame_complete_offset=20,
>>>>>> frame_size=14, oop_maps=0x3ffe00049620,
>>>> caller_must_gc_arguments=false) at
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/compiledMethod.cpp:42
>>>>>> #11 0x00003fffb7421f58 in nmethod::nmethod (this=0x3fff607d0c10,
>>>>>> method=0x3ffe1ddce568, nmethod_size=1768, compile_id=4, entry_bci=-1,
>>>>>> offsets=0x3ffdfe3fdb18, orig_pc_offset=104, debug_info=0x3fffb03d55f0,
>>>>>> dependencies=0x3ffe00049690, code_buffer=0x3ffdfe3fdb40, frame_size=14,
>>>>>> oop_maps=0x3ffe00049620, handler_table=0x3ffdfe3fdad0,
>>>>>> nul_chk_table=0x3ffdfe3fdaf0, compiler=0x3fffb03bc270, comp_level=3) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/nmethod.cpp:706
>>>>>> Now we cast 'code' to 'nmethod' but at this point in time 'code' is
>>>> still a
>>>>>> CodeBlob from the C++ point of view (i.e. it still has a CodeBlob
>>>> vtable
>>>>>> (see [1] for an explanation)).
>>>>>>
>>>>>> Later on, in RelocIterator::initialize() we call virtual methods on the
>>>>>> nmethod which still has the vtable of a "CodeBlob" and this fails
>>>> badly:
>>>>>> #0 SingletonBlob::print_on (this=0x3fff607d0c10, st=0x0) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/codeBlob.cpp:584
>>>>>> #1 0x00003fffb758d51c in RelocIterator::initialize
>>>> (this=0x3ffdfe3fc928,
>>>>>> nm=0x3fff607d0c10, begin=0x3fff607d0fac "\001", limit=0x0) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/relocInfo.cpp:144
>>>>>> #2 0x00003fffb6ace56c in RelocIterator::RelocIterator
>>>>>> (this=0x3ffdfe3fc928, nm=0x3fff607d0c10, begin=0x3fff607d0fac "\001",
>>>>>> limit=0x0) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/relocInfo.hpp:1378
>>>>>> #3 0x00003fffb75919dc in
>>>> trampoline_stub_Relocation::get_trampoline_for
>>>>>> (call=0x3fff607d0fac "\001", code=0x3fff607d0c10) at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/share/vm/code/relocInfo.cpp:849
>>>>>> #4 0x00003fffb741b80c in NativeCall::get_trampoline
>>>> (this=0x3fff607d0fac)
>>>>>> at
>>>>>>
>>>> /usr/work/d046063/OpenJDK/jdk9-hs-comp/hotspot/src/cpu/ppc/vm/nativeInst_ppc.cpp:146
>>>>>> As you can see, we actually want to call nmethod::stub_begin() at
>>>>>> relocInfo.cpp:144
>>>>>>
>>>>>> 142 _section_start[CodeBuffer::SECT_CONSTS] = nm->consts_begin();
>>>>>> 143 _section_start[CodeBuffer::SECT_INSTS ] = nm->insts_begin() ;
>>>>>> 144 _section_start[CodeBuffer::SECT_STUBS ] = nm->stub_begin() ;
>>>>>>
>>>>>> but we actually end up in SingletonBlob::print_on() which is a
>>>> completely
>>>>>> different method. Notice that the call to nm->consts_begin() before
>>>> also
>>>>>> fails, but it doesn't crash the VM because it happens to call
>>>>>> SingletonBlob::verify() which has no bad side effect. The call to
>>>>>> nm->insts_begin() in line 143 is non-virtual and thus works fine. Here
>>>> are
>>>>>> the corresponding vtable slots in the CodeBlob vtable for
>>>> consts_begin()
>>>>>> and stub_begin()
>>>>>>
>>>>>> (gdb) p &nmethod::consts_begin
>>>>>> $76 = &virtual table offset 42
>>>>>> (gdb) p &nmethod::stub_begin
>>>>>> $77 = &virtual table offset 44
>>>>>> (gdb) p ((*(void ***)nm) + 1)[42]
>>>>>> $86 = (void *) 0x3fffb6c41df8 <SingletonBlob::verify()>
>>>>>> (gdb) p ((*(void ***)nm) + 1)[44]
>>>>>> $87 = (void *) 0x3fffb6c41e64 <SingletonBlob::print_on(outputStream*)
>>>> const>
>>>>>> As you can see, 'nm' is indeed a "CodeBlob" at this point:
>>>>>>
>>>>>> (gdb) p *(void ***)nm
>>>>>> $91 = (void **) 0x3fffb7befa00 <vtable for CodeBlob+16>
>>>>>> (gdb) p nm->print()
>>>>>> [CodeBlob (0x00003fff607d1090)]
>>>>>> Framesize: 14
>>>>>>
>>>>>> The offending calls succeeded before your change, because they where
>>>> not
>>>>>> virtual. Any idea how we can fix this with the new class hierarchy?
>>>>>>
>>>>>> Regards,
>>>>>> Volker
>>>>>>
>>>>>> [1]
>>>>>>
>>>> http://stackoverflow.com/questions/6591859/when-does-the-vptr-pointing-to-vtable-get-initialized-for-a-polymorphic-class
>>>>>>
>>>>>>
>>>>>> On Thu, Apr 7, 2016 at 5:50 PM, Volker Simonis <
>>>> volker.simonis at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi Rickard,
>>>>>>>
>>>>>>> I'd also like to know what's the rational behind this quite large
>>>>>>> change. Do you expect some performance or memory consumption
>>>>>>> improvements or is this a prerequisite for another change which is
>>>>>>> still to come?
>>>>>>>
>>>>>>> The change itself currently doesn't work on ppc64 (neither on Linux
>>>>>>> nor on AIX). I get the following crash during the build when the
>>>> newly
>>>>>>> built Hotspot is JIT-compiling java.lang.String::charAt on C1 :
>>>>>>>
>>>>>>> #
>>>>>>> # A fatal error has been detected by the Java Runtime Environment:
>>>>>>> #
>>>>>>> # SIGSEGV (0xb) at pc=0x00001000012a44d0, pid=35331, tid=35404
>>>>>>> #
>>>>>>> # JRE version: OpenJDK Runtime Environment (9.0) (slowdebug build
>>>>>>> 9-internal+0-2016-04-07-162501.d046063.jdk9-hs-comp)
>>>>>>> # Java VM: OpenJDK 64-Bit Server VM (slowdebug
>>>>>>> 9-internal+0-2016-04-07-162501.d046063.jdk9-hs-comp, mixed mode,
>>>>>>> tiered, compressed oo
>>>>>>> ps, serial gc, linux-ppc64le)
>>>>>>> # Problematic frame:
>>>>>>> # V [libjvm.so+0xf744d0] outputStream::do_vsnprintf_and_write(char
>>>>>>> const*, char*, bool)+0x40
>>>>>>> #
>>>>>>> # No core dump will be written. Core dumps have been disabled. To
>>>>>>> enable core dumping, try "ulimit -c unlimited" before starting Java
>>>>>>> again
>>>>>>> #
>>>>>>> # If you would like to submit a bug report, please visit:
>>>>>>> # http://bugreport.java.com/bugreport/crash.jsp
>>>>>>> #
>>>>>>>
>>>>>>> --------------- S U M M A R Y ------------
>>>>>>>
>>>>>>> Command Line:
>>>>>>>
>>>> -Dapplication.home=/sapmnt/ld9510/a/d046063/output-jdk9-hs-comp-dbg/jdk
>>>>>>> -Xms8m -XX:+UseSerialGC -Xms32M -Xmx512M -Djdk.
>>>>>>> module.main=jdk.jlink jdk.jlink/jdk.tools.jmod.Main create
>>>>>>> --module-version 9-internal --os-name Linux --os-arch ppc64le
>>>>>>> --os-version
>>>>>>> 2.6 --modulepath /priv/d046063/output-jdk9-hs-comp-dbg/images/jmods
>>>>>>> --hash-dependencies .* --exclude **_the.* --libs
>>>>>>>
>>>>>>>
>>>> /priv/d046063/output-jdk9-hs-comp-dbg/support/modules_libs-stripped/java.base
>>>>>>> --cmds
>>>>>>>
>>>> /priv/d046063/output-jdk9-hs-comp-dbg/support/modules_cmds-stripped/java.base
>>>>>>> --config
>>>>>>> /priv/d046063/output-jdk9-hs-comp-dbg/support/modules_conf/java.base
>>>>>>> --class-path
>>>> /priv/d046063/output-jdk9-hs-comp-dbg/jdk/modules/java.base
>>>>>>> /priv/d046063/output-jdk9-hs-comp-dbg/support/jmods/java.base.jmod
>>>>>>>
>>>>>>> Host: ld9510, POWER8E (raw), altivec supported, 48 cores, 61G, #
>>>>>>> Please check /etc/os-release for details about this release.
>>>>>>> Time: Thu Apr 7 16:28:55 2016 CEST elapsed time: 0 seconds (0d 0h
>>>> 0m 0s)
>>>>>>> --------------- T H R E A D ---------------
>>>>>>>
>>>>>>> Current thread (0x000010000429c800): JavaThread "C1
>>>> CompilerThread10"
>>>>>>> daemon [_thread_in_vm, id=35404,
>>>>>>> stack(0x000010006a800000,0x000010006ac00000)]
>>>>>>>
>>>>>>>
>>>>>>> Current CompileTask:
>>>>>>> C1: 761 3 3 java.lang.String::charAt (25 bytes)
>>>>>>>
>>>>>>> Stack: [0x000010006a800000,0x000010006ac00000],
>>>>>>> sp=0x000010006abfc6c0, free space=4081k
>>>>>>> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code,
>>>> C=native
>>>>>>> code)
>>>>>>> V [libjvm.so+0xf744d0] outputStream::do_vsnprintf_and_write(char
>>>>>>> const*, char*, bool)+0x40
>>>>>>> V [libjvm.so+0xf74668] outputStream::print_cr(char const*,
>>>> ...)+0x68
>>>>>>> V [libjvm.so+0x72189c] CodeBlob::print_on(outputStream*) const+0x50
>>>>>>> V [libjvm.so+0x723bdc] RuntimeBlob::print_on(outputStream*)
>>>> const+0x40
>>>>>>> V [libjvm.so+0x721eb0] SingletonBlob::print_on(outputStream*)
>>>> const+0x4c
>>>>>>> V [libjvm.so+0x106d51c] RelocIterator::initialize(CompiledMethod*,
>>>>>>> unsigned char*, unsigned char*)+0x170
>>>>>>> V [libjvm.so+0x5ae56c]
>>>> RelocIterator::RelocIterator(CompiledMethod*,
>>>>>>> unsigned char*, unsigned char*)+0x78
>>>>>>> V [libjvm.so+0x10719dc]
>>>>>>> trampoline_stub_Relocation::get_trampoline_for(unsigned char*,
>>>>>>> nmethod*)+0x78
>>>>>>> V [libjvm.so+0xefb80c] NativeCall::get_trampoline()+0x110
>>>>>>> V [libjvm.so+0x1076914] Relocation::pd_call_destination(unsigned
>>>>>>> char*)+0x150
>>>>>>> V [libjvm.so+0x106f5fc]
>>>>>>> CallRelocation::fix_relocation_after_move(CodeBuffer const*,
>>>>>>> CodeBuffer*)+0x74
>>>>>>> V [libjvm.so+0x728898] CodeBuffer::relocate_code_to(CodeBuffer*)
>>>>>>> const+0x390
>>>>>>> V [libjvm.so+0x728404] CodeBuffer::copy_code_to(CodeBlob*)+0x134
>>>>>>> V [libjvm.so+0x722670]
>>>> CodeBuffer::copy_code_and_locs_to(CodeBlob*)+0x84
>>>>>>> V [libjvm.so+0x71f834] CodeBlob::CodeBlob(char const*,
>>>>>>> CodeBlobLayout const&, CodeBuffer*, int, int, OopMapSet*, bool,
>>>>>>> int)+0x320
>>>>>>> V [libjvm.so+0x7c52c8] CompiledMethod::CompiledMethod(Method*, char
>>>>>>> const*, int, int, CodeBuffer*, int, int, OopMapSet*, bool)+0xd8
>>>>>>> V [libjvm.so+0xf01f58] nmethod::nmethod(Method*, int, int, int,
>>>>>>> CodeOffsets*, int, DebugInformationRecorder*, Dependencies*,
>>>>>>> CodeBuffer*, int, OopMapSet*, ExceptionHandlerTable*,
>>>>>>> ImplicitExceptionTable*, AbstractCompiler*, int)+0xe0
>>>>>>> V [libjvm.so+0xf01610] nmethod::new_nmethod(methodHandle const&,
>>>>>>> int, int, CodeOffsets*, int, DebugInformationRecorder*,
>>>> Dependencies*,
>>>>>>> CodeBuffer*, int, OopMapSet*, ExceptionHandlerTable*,
>>>>>>> ImplicitExceptionTable*, AbstractCompiler*, int)+0x2c4
>>>>>>> V [libjvm.so+0x632970] ciEnv::register_method(ciMethod*, int,
>>>>>>> CodeOffsets*, int, CodeBuffer*, int, OopMapSet*,
>>>>>>> ExceptionHandlerTable*, ImplicitExceptionTable*, AbstractCompiler*,
>>>>>>> bool, bool, RTMState)+0x560
>>>>>>> V [libjvm.so+0x48ee00] Compilation::install_code(int)+0x264
>>>>>>> V [libjvm.so+0x48eff8] Compilation::compile_method()+0x184
>>>>>>> V [libjvm.so+0x48f7a8] Compilation::Compilation(AbstractCompiler*,
>>>>>>> ciEnv*, ciMethod*, int, BufferBlob*, DirectiveSet*)+0x288
>>>>>>> V [libjvm.so+0x4980d0] Compiler::compile_method(ciEnv*, ciMethod*,
>>>>>>> int, DirectiveSet*)+0xc8
>>>>>>> V [libjvm.so+0x7b188c]
>>>>>>> CompileBroker::invoke_compiler_on_method(CompileTask*)+0x590
>>>>>>> V [libjvm.so+0x7b07bc] CompileBroker::compiler_thread_loop()+0x310
>>>>>>> V [libjvm.so+0x11a614c] compiler_thread_entry(JavaThread*,
>>>> Thread*)+0xa0
>>>>>>> V [libjvm.so+0x119f3a8] JavaThread::thread_main_inner()+0x1b4
>>>>>>> V [libjvm.so+0x119f1a4] JavaThread::run()+0x1b8
>>>>>>> V [libjvm.so+0xf53d90] java_start(Thread*)+0x204
>>>>>>> C [libpthread.so.0+0x8a64] start_thread+0xf4
>>>>>>> C [libc.so.6+0x1032a0] clone+0x98
>>>>>>>
>>>>>>> I haven't identified the exact cause (will analyze it tomorrow) but
>>>>>>> the stack trace indicates that it is indeed related to your changes.
>>>>>>>
>>>>>>> Besides that I have some comments:
>>>>>>>
>>>>>>> codeBuffer.hpp:
>>>>>>>
>>>>>>> 472 CodeSection* insts() { return &_insts; }
>>>>>>> 475 const CodeSection* insts() const { return &_insts; }
>>>>>>>
>>>>>>> - do we really need both versions?
>>>>>>>
>>>>>>> codeBlob.hpp:
>>>>>>>
>>>>>>> 135 nmethod* as_nmethod_or_null() const { return
>>>>>>> is_nmethod() ? (nmethod*) this : NULL; }
>>>>>>> 136 nmethod* as_nmethod() const {
>>>>>>> assert(is_nmethod(), "must be nmethod"); return (nmethod*) this; }
>>>>>>> 137 CompiledMethod* as_compiled_method_or_null() const { return
>>>>>>> is_compiled() ? (CompiledMethod*) this : NULL; }
>>>>>>> 138 CompiledMethod* as_compiled_method() const {
>>>>>>> assert(is_compiled(), "must be compiled"); return (CompiledMethod*)
>>>>>>> this; }
>>>>>>> 139 CodeBlob* as_codeblob_or_null() const { return
>>>>>>> (CodeBlob*) this; }
>>>>>>>
>>>>>>> - I don't like this code. You make the getters 'const' which
>>>>>>> implicitely makes 'this' a "pointer to const" but then the returned
>>>>>>> pointer is a normal pointer to a non-const object and therefore you
>>>>>>> have to statically cast away the "pointer to const" (that's why you
>>>>>>> need the cast even in the case where you return a CodeBlob*). So
>>>>>>> either remove the const qualifier from the method declarations or
>>>> make
>>>>>>> them return "pointers to const". And by the way,
>>>> as_codeblob_or_null()
>>>>>>> doesn't seemed to be used anywhere in the code, why do we need it at
>>>>>>> all?
>>>>>>>
>>>>>>> - Why do we need the non-virtual methods is_nmethod() and
>>>>>>> is_compiled() to manually simulate virtual behavior. Why can't we
>>>>>>> simply make them virtual and implement them accordingly in nmathod
>>>> and
>>>>>>> CompiledMethod?
>>>>>>>
>>>>>>> Regards,
>>>>>>> Volker
>>>>>>>
>>>>>>> On Thu, Apr 7, 2016 at 2:12 PM, Rickard Bäckman
>>>>>>> <rickard.backman at oracle.com> wrote:
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> can I please have review for this patch please?
>>>>>>>>
>>>>>>>> So far CodeBlobs have required all the data (metadata, oops, code,
>>>> etc)
>>>>>>>> to be in one continuous blob With this patch we are looking to
>>>> change
>>>>>>>> that. It's been done by changing offsets in CodeBlob to addresses,
>>>>>>>> making some methods virtual to allow different behavior and also
>>>>>>>> creating a couple of new classes. CompiledMethod now sits inbetween
>>>>>>>> CodeBlob and nmethod.
>>>>>>>>
>>>>>>>> CR: https://bugs.openjdk.java.net/browse/JDK-8152664
>>>>>>>> Webrev: http://cr.openjdk.java.net/~rbackman/8152664/
>>>>>>>>
>>>>>>>> Thanks
>>>>>>>> /R
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