shenandoah c2 compiler crash in jdk8

[Nick Evgeniev]

Hi,

It stops crashing if I add `-XX:MaxNodeLimit=100000` option.. Is it true
that Shenandoah needs substantially more nodes compared to CMS? If so,
default (75000) probably needs to be adjusted... as crash in release
version has less than obvious stacktrace

Pls confirm it's not a bug :)

On Fri, 30 Oct 2020 at 21:16, Nick Evgeniev <nevgeniev at gmail.com> wrote:

> hi,
>
> pls disregard previous email it's not related to existing jdk bug
>
> #
> # A fatal error has been detected by the Java Runtime Environment:
> #
> #  Internal Error
> (/home/buildbot/worker/build-jdk8u-redhat-linux/build/hotspot/src/share/vm/opto/node.cpp:75),
> pid=101496, tid=0x00007fd2b0cb1700
> #  assert(Compile::current()->live_nodes() <
> Compile::current()->max_node_limit()) failed: Live Node limit exceeded limit
> #
> # JRE version: OpenJDK Runtime Environment (8.0) (build
> 1.8.0-builds.shipilev.net-openjdk-jdk8-redhat-b175-20201026-debug-testing-b00)
> # Java VM: OpenJDK 64-Bit Server VM (25.71-b00-debug mixed mode
> linux-amd64 compressed oops)
> # Core dump written. Default location:
> /home/e21170/Downloads/core/segv/core or core.101496
> #
> # If you would like to submit a bug report, please visit:
> #   http://bugreport.java.com/bugreport/crash.jsp
> #
>
> ---------------  T H R E A D  ---------------
>
> Current thread (0x00007fd2ac204830):  JavaThread "C2 CompilerThread0"
> daemon [_thread_in_native, id=101889,
> stack(0x00007fd2b0bb2000,0x00007fd2b0cb2000)]
>
> Stack: [0x00007fd2b0bb2000,0x00007fd2b0cb2000],  sp=0x00007fd2b0cab2a0,
>  free space=996k
> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native
> code)
> V  [libjvm.so+0xe0a497]  VMError::report(outputStream*)+0xf0d
> V  [libjvm.so+0xe0b903]  VMError::report_and_die()+0x475
> V  [libjvm.so+0x68cef0]  report_vm_error(char const*, int, char const*,
> char const*)+0xa5
> V  [libjvm.so+0xb92ec3]  Node::verify_construction()+0x155
> V  [libjvm.so+0xb93d18]  Node::Node(Node*, Node*)+0x62
> V  [libjvm.so+0x3dc8a1]  CastX2PNode::CastX2PNode(Node*)+0x25
> V  [libjvm.so+0xd1381f]
>  ShenandoahBarrierC2Support::pin_and_expand(PhaseIdealLoop*)+0x2629
> V  [libjvm.so+0xab474c]  PhaseIdealLoop::build_and_optimize(bool,
> bool)+0xc82
> V  [libjvm.so+0x61eb88]  PhaseIdealLoop::PhaseIdealLoop(PhaseIterGVN&,
> bool, bool)+0xac
> V  [libjvm.so+0xd0b2b9]  ShenandoahBarrierC2Support::expand(Compile*,
> PhaseIterGVN&)+0x67
> V  [libjvm.so+0x614694]  Compile::Optimize()+0xf22
> V  [libjvm.so+0x60dc0e]  Compile::Compile(ciEnv*, C2Compiler*, ciMethod*,
> int, bool, bool, bool)+0x12ba
> V  [libjvm.so+0x53f1ad]  C2Compiler::compile_method(ciEnv*, ciMethod*,
> int)+0x119
> V  [libjvm.so+0x626c2f]
>  CompileBroker::invoke_compiler_on_method(CompileTask*)+0x4d3
> V  [libjvm.so+0x626051]  CompileBroker::compiler_thread_loop()+0x32b
> V  [libjvm.so+0xdae72c]  compiler_thread_entry(JavaThread*, Thread*)+0x57
>