IV30270: JIT CRASH CAUSED BY Z/OS V1R11 C COMPILER LIMITATION

APAR status

• Closed as program error.

Error description

• Error Message: On z/OS, the Java JIT compiler crashes in global
  value propagation during the compilation of a method.
  .
  Stack Trace:
  TR_J9VM::getBaseComponentClass(TR_OpaqueClassBlock*,int&)+0x3a
  TR_J9VMBase::getClassSignature(TR_OpaqueClassBlock*,int&,TR_Memo
  ry*)+0x2e
  TR_VPFixedClass::create(TR_ValuePropagation*,TR_OpaqueClassBlock
  *)+0x114
  constrainIfcmpeqne(TR_ValuePropagation*,TR_Node*,bool)+0x257e
  constrainIfcmpne(TR_ValuePropagation*,TR_Node*)+0xc
  TR_ValuePropagation::processTrees(TR_TreeTop*,TR_TreeTop*)+0x410
  TR_GlobalValuePropagation::processBlock(TR_StructureSubGraphNode
  *,bool,bool)+0x438
  TR_GlobalValuePropagation::processRegionNode(TR_StructureSubGrap
  hNode*,bool,bool)+0x662
  TR_GlobalValuePropagation::processRegionNode(TR_StructureSubGrap
  hNode*,bool,bool)+0x7e
  TR_GlobalValuePropagation::processRegionSubgraph(TR_StructureSub
  GraphNode*,bool,bool,bool)+0x240
  TR_GlobalValuePropagation::perform()+0x498
  TR_OptimizerImpl::performOptimization(TR_OptimizerImpl::Optimiza
  tion*,int,int,int)+0x1d90
  TR_OptimizerImpl::performOptimization(TR_OptimizerImpl::Optimiza
  tion*,int,int,int)+0x994
  TR_OptimizerImpl::optimize()+0x2f4
  TR_Compilation::compile()+0xd52
  .
  

Local fix

• This problem can be avoided by setting the JVM option
  -Xjit:disableGlobalVP. However, this will cause significant
  performance degradation.
  

Problem summary

• The incorrect behaviour of the JIT compiler results from a
  limitation in the z/OS V1R11 C compiler, which was used to build
  the JVM.
  

Problem conclusion

• This defect will be fixed in:
  7.0.0 SR3
  6.0.1 SR4
  .
  The JIT compiler source code has been modified to avoid the
  issue.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R260 PSY

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