RFR (XS): 8208480: Fix for test failure: assert(is_bound() || is_unused()) after JDK-8206075 in C1
Vladimir Kozlov
vladimir.kozlov at oracle.com
Wed Aug 22 16:30:30 UTC 2018
What is blocking push?
Testing passed on our side.
Thanks,
Vladimir
On 8/20/18 3:13 PM, Hohensee, Paul wrote:
> LGTM (I'm a reviewer).
>
> Thanks,
>
> Paul
>
> On 8/20/18, 10:27 AM, "hotspot-runtime-dev on behalf of Liu, Xin" <hotspot-runtime-dev-bounces at openjdk.java.net on behalf of xxinliu at amazon.com> wrote:
>
> Hi, Gunter,
> It looks good to me, but I am not a reviewer.
>
> Now I can explain why LIR_Assembler::bailout doesn't work out.
> LinearScan has its own bailout. BAILOUT/BAILOUT_ in c1_LinearScan.cpp will use LinearScan::bailout. It won't reset LIRAssembler:: _unwind_handler_entry.
>
> Actually, not only LinearScan, c1_GraphBulider , FpuStackAllocator all has private bailout methods. I ignored this fact at first place. Your reset in dtor is correct.
>
> Thanks,
> --lx
>
> On 8/20/18, 7:23 AM, "Haug, Gunter" <gunter.haug at sap.com> wrote:
>
> Hi all,
>
> Here is the updated webrev:
>
> http://cr.openjdk.java.net/~ghaug/webrevs/8208480.v1/
>
> I have removed the redundant reset of the label.
>
> Best regards,
> Gunter
>
> On 20.08.18, 10:00, "Haug, Gunter" <gunter.haug at sap.com> wrote:
>
> Hi all,
>
> the bail-out path originates from Compilation::emit_code_epilog not from LIR_Assembler. The design using the CHECK_BAILOUT() macro is a bit unfortunate in this case. I found it the easiest solution to reset the label in the destructor.
>
> In fact you're right, my change makes the original bail-out support redundant, I'll prepare an updated webrev.
>
> Best regards,
> Gunter
>
>
>
> From: Liu Xin <navy.xliu at gmail.com>
> Date: Friday, 17. August 2018 at 21:03
> To: Lutz Schmidt <lutz.schmidt at sap.com>
> Cc: "Haug, Gunter" <gunter.haug at sap.com>, "hotspot-runtime-dev at openjdk.java.net" <hotspot-runtime-dev at openjdk.java.net>, "Doerr, Martin" <martin.doerr at sap.com>, "xxinliu at amazon.com" <xxinliu at amazon.com>
> Subject: Re: RFR (XS): 8208480: Fix for test failure: assert(is_bound() || is_unused()) after JDK-8206075 in C1
>
> hi, Lutz and Gunter,
>
> Thank you for providing the information.
> I met the full codecache in C1 in compiler/codegen/TestCharVect2.java
> In my understanding, Compilation::emit_code_epilog(LIR_Assembler* assembler) checks bailout for every statement.
> Do you meet the problem only on s390?
>
> I am not object to your patch. if you need to reset the label in c1_LIRAssember's dtor, I think bailout change is redundant.
> Remove it make code clearer.
>
> diff -r fbb62267e5e9 src/hotspot/share/c1/c1_LIRAssembler.cpp
> --- a/src/hotspot/share/c1/c1_LIRAssembler.cpp
> Thu Aug 09 15:52:23 2018 -0700
> +++ b/src/hotspot/share/c1/c1_LIRAssembler.cpp
> Fri Aug 17 11:57:21 2018 -0700
> @@ -112,6 +112,9 @@
>
>
> LIR_Assembler::~LIR_Assembler() {
> + // The unwind handler label may be unbound if this destructor is invoked because of a bail-out.
> + // Reset it here to avoid an assertion.
> + _unwind_handler_entry.reset();
> }
>
>
> diff -r fbb62267e5e9 src/hotspot/share/c1/c1_LIRAssembler.hpp
> --- a/src/hotspot/share/c1/c1_LIRAssembler.hpp
> Thu Aug 09 15:52:23 2018 -0700
> +++ b/src/hotspot/share/c1/c1_LIRAssembler.hpp
> Fri Aug 17 11:57:21 2018 -0700
> @@ -71,11 +71,7 @@
> void record_non_safepoint_debug_info();
>
> // unified bailout support
> - void bailout(const char* msg) {
> - // reset the label in case it hits assertion in destructor.
> - _unwind_handler_entry.reset();
> - compilation()->bailout(msg);
> - }
> + void bailout(const char* msg) const { compilation()->bailout(msg); }
> bool bailed_out() const { return compilation()->bailed_out(); }
>
> // code emission patterns and accessors
>
>
> On Fri, Aug 17, 2018 at 8:35 AM Schmidt, Lutz <mailto:lutz.schmidt at sap.com> wrote:
> Hi,
>
> I’m responding on Gunter’s behalf. He just left the office a few minutes ago.
>
> The bailout case was a “codecache full” condition. For the error to occur, you must run into that condition when a reference to the label is already generated, but the label is not bound yet. This is not JCK test specific. We just happened to hit “codecache full” there.
>
> “jck_simple_api” is a subset of the api suite we compiled for our own purposes. The tests contained therein are just “simple” tests: they do not run too long, they can run massively parallel, they do not depend on specific resources (like ports, addresses, …).
>
> I’m afraid this doesn’t help you much. At least I tried. �� If you can’t reproduce on your own, please let us know what tracing you need. We could then try to produce the output on our test systems.
>
> Thanks,
> Lutz
>
> From: Liu Xin <mailto:navy.xliu at gmail.com>
> Date: Friday, 17. August 2018 at 17:15
> To: "Haug, Gunter" <mailto:gunter.haug at sap.com>
> Cc: "mailto:hotspot-runtime-dev at openjdk.java.net" <mailto:hotspot-runtime-dev at openjdk.java.net>, Lutz Schmidt <mailto:lutz.schmidt at sap.com>, "Doerr, Martin (mailto:martin.doerr at sap.com)" <mailto:martin.doerr at sap.com>, "mailto:xxinliu at amazon.com" <mailto:xxinliu at amazon.com>
> Subject: Re: RFR (XS): 8208480: Fix for test failure: assert(is_bound() || is_unused()) after JDK-8206075 in C1
>
> hi, Gunter,
> I do consider bailout case. why didn't it catch your case?
> c1_LIRAssember.hpp
> // unified bailout support
> void bailout(const char* msg) {
> // reset the label in case it hits assertion in destructor.
> _unwind_handler_entry.reset();
> compilation()->bailout(msg);
> }
>
> can I reproduce this jck_simple_api_work?
> /priv/jvmtests/output_sapjvm12_o_jdk-test_dbgU_linuxs390x/jck_simple_api_work/hs_err_pid108809.log
>
> On Fri, Aug 17, 2018 at 6:39 AM Haug, Gunter <mailto:gunter.haug at sap.com> wrote:
> Hi all,
>
> could I please have a review and a sponsor for this tiny fix:
>
> https://bugs.openjdk.java.net/browse/JDK-8208480
> http://cr.openjdk.java.net/~ghaug/webrevs/8208480
>
> C1 holds a label to the unwind handler during compilation. There are bail-out paths where a branch to this label has already been emitted but the handler hasn't (e.g. code cache full). The label is therefore unbound when the destructor is invoked and the assertion fires.
>
> Thanks,
> Gunter
>
>
>
>
>
>
>
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