RFR: remove obsolete code

[Aleksey Shipilev]

On 08/10/2018 05:57 PM, Roland Westrelin wrote:
> 
> http://cr.openjdk.java.net/~roland/shenandoah/cleanup-nobarrieronconst-nowbinasm/webrev.00/
> 
> This removes some code that's obsolete now that:
> 
> - barriers are never added on constant oops
> - write barriers are always expanded to IR
> 
> + some other trivial cleanup.
> 
> I haven't run testing with this. What what would be the recommended
> testing?

This patch seems to foobar XmlTransform like this:

# A fatal error has been detected by the Java Runtime Environment:
#
#  Internal Error
(/home/shade/trunks/shenandoah-jdk/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp:919),
pid=16443, tid=16487
#  assert(wb->Opcode() == Op_ShenandoahWriteBarrier) failed: expect write barrier
#
# JRE version: OpenJDK Runtime Environment (12.0) (fastdebug build
12-internal+0-adhoc.shade.shenandoah-jdk)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 12-internal+0-adhoc.shade.shenandoah-jdk, mixed mode,
tiered, compressed oops, shenandoah gc, linux-amd64)
# Core dump will be written. Default location: Core dumps may be processed with
"/usr/share/apport/apport %p %s %c %d %P" (or dumping to
/home/shade/projects/redhat-benchmarks/core.16443)
#
# 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: -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -Xmx16g
-XX:CompileCommandFile=/tmp/jmh16039876787592435825compilecommand org.openjdk.jmh.runner.ForkedMain
127.0.0.1 43805

Host: shade-desktop, Intel(R) Core(TM) i7-7820X CPU @ 3.60GHz, 16 cores, 125G, Ubuntu 18.04 LTS
Time: Wed Aug 15 10:07:43 2018 CEST elapsed time: 33 seconds (0d 0h 0m 33s)

---------------  T H R E A D  ---------------

Current thread (0x00007f15f0117000):  JavaThread "C2 CompilerThread7" daemon [_thread_in_native,
id=16487, stack(0x00007f1668f73000,0x00007f1669074000)]


Current CompileTask:
C2:  33507 11316       4       com.sun.org.apache.xml.internal.dtm.ref.DTMStringPool::<init> (47 bytes)

Stack: [0x00007f1668f73000,0x00007f1669074000],  sp=0x00007f166906e6b0,  free space=1005k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native
code)
V  [libjvm.so+0x20111a4]  VMError::report_and_die(int, char const*, char const*, __va_list_tag*,
Thread*, unsigned char*, void*, void*, char const*, int, unsigned long)+0x314
V  [libjvm.so+0x201208f]  VMError::report_and_die(Thread*, void*, char const*, int, char const*,
char const*, __va_list_tag*)+0x2f
V  [libjvm.so+0xbb8b2a]  report_vm_error(char const*, int, char const*, char const*, ...)+0x12a
V  [libjvm.so+0x191540f]  ShenandoahWBMemProjNode::Identity(PhaseGVN*)+0x8f
V  [libjvm.so+0x1656d78]  PhaseIterGVN::transform_old(Node*)+0x2d8
V  [libjvm.so+0x1652714]  PhaseIterGVN::optimize()+0x44
V  [libjvm.so+0xabdd2f]  Compile::remove_speculative_types(PhaseIterGVN&) [clone .part.340]+0x2df
V  [libjvm.so+0xad6a1b]  Compile::Optimize()+0x80b
V  [libjvm.so+0xad7ee9]  Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, bool, bool, bool,
DirectiveSet*)+0xcf9
V  [libjvm.so+0x8bfac0]  C2Compiler::compile_method(ciEnv*, ciMethod*, int, DirectiveSet*)+0xe0
V  [libjvm.so+0xae56aa]  CompileBroker::invoke_compiler_on_method(CompileTask*)+0x3fa
V  [libjvm.so+0xae6677]  CompileBroker::compiler_thread_loop()+0x347
V  [libjvm.so+0x1f41ed3]  JavaThread::thread_main_inner()+0x233
V  [libjvm.so+0x1f4211a]  JavaThread::run()+0x18a
V  [libjvm.so+0x15aba20]  thread_native_entry(Thread*)+0x100


Thanks,
-Aleksey