JitDump.cpp

/*******************************************************************************
 * Copyright IBM Corp. and others 2020
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which accompanies this
 * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
 * or the Apache License, Version 2.0 which accompanies this distribution and
 * is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * This Source Code may also be made available under the following
 * Secondary Licenses when the conditions for such availability set
 * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
 * General Public License, version 2 with the GNU Classpath
 * Exception [1] and GNU General Public License, version 2 with the
 * OpenJDK Assembly Exception [2].
 *
 * [1] https://www.gnu.org/software/classpath/license.html
 * [2] https://openjdk.org/legal/assembly-exception.html
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
 *******************************************************************************/

#include "control/JitDump.hpp"

#include "codegen/CodeGenerator.hpp"
#include "env/VMJ9.h"
#include "control/MethodToBeCompiled.hpp"
#include "control/CompilationRuntime.hpp"
#include "control/CompilationThread.hpp"
#include "env/ut_j9jit.h"
#include "env/VMAccessCriticalSection.hpp"
#include "ilgen/J9ByteCodeIlGenerator.hpp"
#include "nls/j9dmpnls.h"
#if defined(J9VM_OPT_JITSERVER)
#include "control/JITServerCompilationThread.hpp"
#include "control/JITServerHelpers.hpp"
#include "runtime/JITServerAOTCache.hpp"
#include "runtime/JITServerAOTDeserializer.hpp"
#include "runtime/JITServerIProfiler.hpp"
#include "runtime/JITServerStatisticsThread.hpp"
#include "runtime/Listener.hpp"
#if defined(LINUX)
#include <malloc.h> // for malloc_stats() (Linux glibc only)
#endif /* defined(LINUX) */
#endif /* defined(J9VM_OPT_JITSERVER) */


struct ILOfCrashedThreadParamenters
   {
   ILOfCrashedThreadParamenters(J9VMThread *vmThread, TR::Compilation *comp, TR::FILE *jitdumpFile)
   : vmThread(vmThread), comp(comp), jitdumpFile(jitdumpFile)
      {}

   /// The JVM thread backing the crashed thread
   J9VMThread *vmThread;

   /// The compilation object extracted from the crashed thread
   TR::Compilation *comp;

   /// The jitdump file to trace the IL of the crashed thread to
   TR::FILE *jitdumpFile;
   };

static uintptr_t
traceILOfCrashedThreadProtected(struct J9PortLibrary *portLib, void *handler_arg)
   {
   auto p = *static_cast<ILOfCrashedThreadParamenters*>(handler_arg);

   TR_J9ByteCodeIlGenerator bci(p.comp->ilGenRequest().details(), p.comp->getMethodSymbol(),
      TR_J9VMBase::get(p.vmThread->javaVM->jitConfig, p.vmThread), p.comp, p.comp->getSymRefTab());
   bci.printByteCodes();

   // This call will reset the previously recorded symbol reference size to 0, thus indicating to the debug object that
   // we should print all the symbol references in the symbol reference table when tracing the trees. By default the
   // debug object will only print new symbol references since the last time they were printed. Here we are in a
   // crashed thread state so we can safely reset this coutner so we print all the symbol references.
   p.comp->setPrevSymRefTabSize(0);
   p.comp->dumpMethodTrees("Trees");

   if ((p.vmThread->omrVMThread->vmState & J9VMSTATE_JIT_CODEGEN) == J9VMSTATE_JIT_CODEGEN)
      {
      TR_Debug *debug = p.comp->getDebug();
      debug->dumpMethodInstrs(p.jitdumpFile, "Post Binary Instructions", false, true);
      debug->print(p.jitdumpFile, p.comp->cg()->getSnippetList());
      debug->dumpMixedModeDisassembly();
      }
   else if ((p.vmThread->omrVMThread->vmState & J9VMSTATE_JIT_OPTIMIZER) == J9VMSTATE_JIT_OPTIMIZER)
      {
      // Tree verification is only valid during optimizations as it relies on consistent node counts which are only
      // valid before codegen, since the codegen will decrement the node counts as part of instruction selection
      p.comp->verifyTrees();
      p.comp->verifyBlocks();
      }

   return 0;
   }

static void
traceILOfCrashedThread(J9VMThread *vmThread, TR::Compilation *comp, TR::FILE *jitdumpFile)
   {
   PORT_ACCESS_FROM_VMC(vmThread);
   j9nls_printf(PORTLIB, J9NLS_INFO | J9NLS_STDERR, J9NLS_DMP_JIT_TRACE_IL_CRASHED_THREAD);

   bool alreadyHaveVMAccess = ((vmThread->publicFlags & J9_PUBLIC_FLAGS_VM_ACCESS) != 0);
   bool haveAcquiredVMAccess = false;
   if (!alreadyHaveVMAccess)
      {
      if (0 == vmThread->javaVM->internalVMFunctions->internalTryAcquireVMAccessWithMask(vmThread, J9_PUBLIC_FLAGS_HALT_THREAD_ANY_NO_JAVA_SUSPEND))
         {
         haveAcquiredVMAccess = true;
         }
      }
   
   comp->setOutFile(jitdumpFile);

   TR_Debug *debug = comp->findOrCreateDebug();
   debug->setFile(jitdumpFile);

   TR::Options *options = comp->getOptions();
   options->setOption(TR_TraceAll);
   options->setOption(TR_TraceKnownObjectGraph);

   trfprintf(jitdumpFile, "<ilOfCrashedThread>\n");

   ILOfCrashedThreadParamenters p(vmThread, comp, jitdumpFile);

   U_32 flags = J9PORT_SIG_FLAG_MAY_RETURN |
                J9PORT_SIG_FLAG_SIGSEGV | J9PORT_SIG_FLAG_SIGFPE |
                J9PORT_SIG_FLAG_SIGILL  | J9PORT_SIG_FLAG_SIGBUS | J9PORT_SIG_FLAG_SIGTRAP;

   uintptr_t result = 0;
   j9sig_protect(traceILOfCrashedThreadProtected, static_cast<void *>(&p),
      jitDumpSignalHandler,
      vmThread, flags, &result);

   trfprintf(jitdumpFile, "</ilOfCrashedThread>\n");

   if (!alreadyHaveVMAccess && haveAcquiredVMAccess)
      {
      vmThread->javaVM->internalVMFunctions->internalReleaseVMAccess(vmThread);
      }
   }

static void
jitDumpRecompileWithTracing(J9VMThread *vmThread, J9Method *ramMethod, TR::CompilationInfo *compInfo, TR_Hotness optLevel, bool isProfilingCompile, TR::Options *optionsFromOriginalCompile, bool isAOTBody, void *oldStartPC, TR::FILE *jitdumpFile)
   {
   PORT_ACCESS_FROM_VMC(vmThread);
   J9Class *clazz;
   J9ROMMethod *romMethod;
   J9UTF8 *methName, *methSig, *className;
#if defined(J9VM_OPT_JITSERVER)
   if (compInfo->getPersistentInfo()->getRemoteCompilationMode() == JITServer::SERVER)
      {
      TR_J9VMBase *fej9 = reinterpret_cast<TR_J9VMBase *>(TR_J9VMBase::get(compInfo->getJITConfig(), vmThread, TR_J9VMBase::J9_SERVER_VM));
      if (!fej9->vmThreadIsCompilationThread())
         {
         trfprintf(jitdumpFile, "JitDump for a non-compilation thread on JITServer is not supported.\n");
         return;
         }

      clazz = reinterpret_cast<J9Class *>(fej9->getClassOfMethod(reinterpret_cast<TR_OpaqueMethodBlock *>(ramMethod)));
      romMethod = JITServerHelpers::romMethodOfRamMethod(ramMethod);
      methName = J9ROMMETHOD_NAME(romMethod);
      methSig = J9ROMMETHOD_SIGNATURE(romMethod);
      className = J9ROMCLASS_CLASSNAME(TR::Compiler->cls.romClassOf(reinterpret_cast<TR_OpaqueClassBlock *>(clazz)));
      }
   else
#endif
      {
      clazz = J9_CLASS_FROM_METHOD(ramMethod);
      romMethod = J9_ROM_METHOD_FROM_RAM_METHOD(ramMethod);
      methName = J9ROMMETHOD_NAME(romMethod);
      methSig = J9ROMMETHOD_SIGNATURE(romMethod);
      className = J9ROMCLASS_CLASSNAME(clazz->romClass);
      }

   j9nls_printf(PORTLIB, J9NLS_INFO | J9NLS_STDERR, J9NLS_DMP_JIT_RECOMPILING_METHOD,
         (UDATA)J9UTF8_LENGTH(className), J9UTF8_DATA(className),
         (UDATA)J9UTF8_LENGTH(methName), J9UTF8_DATA(methName),
         (UDATA)J9UTF8_LENGTH(methSig), J9UTF8_DATA(methSig));

   Trc_JIT_DumpCompilingMethod(vmThread, ramMethod, optLevel, oldStartPC);

   // The request to use a trace log gets passed to the compilation via the optimization plan. The options object
   // created before the compile is issued will use the trace log we provide to initialize IL tracing.
   TR_OptimizationPlan *plan = NULL;
#if defined(J9VM_OPT_JITSERVER)
   // JITServer will create a new optimization plan on the client
   if (compInfo->getPersistentInfo()->getRemoteCompilationMode() != JITServer::SERVER)
#endif
      {
      plan = TR_OptimizationPlan::alloc(optLevel);
      if (NULL == plan)
         {
         j9nls_printf(PORTLIB, J9NLS_INFO | J9NLS_STDERR, J9NLS_DMP_JIT_OPTIMIZATION_PLAN);
         return;
         }

      plan->setInsertInstrumentation(isProfilingCompile);
      plan->setLogCompilation(jitdumpFile);
      }

   trfprintf(jitdumpFile, "<recompilation>\n");

   // Set the VM state of the crashed thread so the diagnostic thread can use consume it
   compInfo->setVMStateOfCrashedThread(vmThread->omrVMThread->vmState);

   J9::JitDumpMethodDetails details(ramMethod, optionsFromOriginalCompile, isAOTBody);
   auto queued = false;
   auto rc = compilationOK;
#if defined(J9VM_OPT_JITSERVER)
   if (compInfo->getPersistentInfo()->getRemoteCompilationMode() == JITServer::SERVER)
      {
      // Inform the client that the compilation thread has crashed and send it
      // a pointer to the JitDump file, so that it can request
      // a JitDump recompilation from the server with an updated plan and method details.
      TR_MethodToBeCompiled *entry = TR::compInfoPT->getMethodBeingCompiled();
      JITServer::ServerStream *stream = entry->_stream;
      stream->write(JITServer::MessageType::compilationThreadCrashed, jitdumpFile);
      stream->read<JITServer::Void>();
         {
         // Add an entry to the compilation queue using the current stream,
         // and immediatelly set its method details as JitDump method details,
         // so that only the diagnostic thread can compile it.
         OMR::CriticalSection compilationMonitorLock(compInfo->getCompilationMonitor());

         compInfo->requeueOutOfProcessEntry(entry);
         entry->_methodDetails = TR::IlGeneratorMethodDetails::clone(entry->_methodDetailsStorage, details);
         queued = true;
         }
      // Wait for the recompilation to finish
      entry->acquireSlotMonitor(vmThread);
      entry->getMonitor()->wait();
      entry->releaseSlotMonitor(vmThread);
      }
   else
#endif
      {
      compInfo->compileMethod(vmThread, details, oldStartPC, TR_no, &rc, &queued, plan);
      }

   trfprintf(jitdumpFile, "</recompilation rc=%d queued=%d>\n", rc, queued);

   if (!queued
#if defined(J9VM_OPT_JITSERVER)
       && compInfo->getPersistentInfo()->getRemoteCompilationMode() != JITServer::SERVER
#endif
       )
      {
      TR_OptimizationPlan::freeOptimizationPlan(plan);
      }
   }

uintptr_t
jitDumpSignalHandler(struct J9PortLibrary *portLibrary, uint32_t gpType, void *gpInfo, void *handler_arg)
   {
   PORT_ACCESS_FROM_VMC(reinterpret_cast<J9VMThread*>(handler_arg));
   j9nls_printf(PORTLIB, J9NLS_INFO | J9NLS_STDERR, J9NLS_DMP_JIT_RECURSIVE_CRASH);
   return J9PORT_SIG_EXCEPTION_RETURN;
   }

static UDATA
jitDumpStackFrameIterator(J9VMThread *currentThread, J9StackWalkState *walkState)
   {
   Trc_JIT_DumpWalkingFrame(currentThread);

   if (NULL != walkState->jitInfo)
      {
      auto *bodyInfo = reinterpret_cast<TR_PersistentJittedBodyInfo *>(walkState->jitInfo->bodyInfo);
      if (NULL != bodyInfo)
         {
            jitDumpRecompileWithTracing(
               currentThread,
               walkState->method,
               reinterpret_cast<TR::CompilationInfo*>(walkState->userData1),
               bodyInfo->getHotness(),
               bodyInfo->getIsProfilingBody(),
               NULL,
               bodyInfo->getIsAotedBody(),
               bodyInfo->getStartPCAfterPreviousCompile(),
               reinterpret_cast<TR::FILE*>(walkState->userData2)
            );
         }
      }

   return J9_STACKWALK_KEEP_ITERATING;
   }

omr_error_t
runJitdump(char *label, J9RASdumpContext *context, J9RASdumpAgent *agent)
   {
   PORT_ACCESS_FROM_VMC(context);

   J9VMThread *crashedThread = context->javaVM->internalVMFunctions->currentVMThread(context->javaVM);
   Trc_JIT_DumpStart(crashedThread);

#if defined(J9VM_OPT_JITSERVER)
   if (context && context->javaVM && context->javaVM->jitConfig)
      {
      J9JITConfig *jitConfig = context->javaVM->jitConfig;
      TR::CompilationInfo *compInfo = TR::CompilationInfo::get(context->javaVM->jitConfig);
      if (compInfo)
         {
         static char *isPrintJITServerMsgStats = feGetEnv("TR_PrintJITServerMsgStats");
         if (isPrintJITServerMsgStats)
            JITServerHelpers::printJITServerMsgStats(jitConfig, compInfo);

         static char *isPrintJITServerCHTableStats = feGetEnv("TR_PrintJITServerCHTableStats");
         if (isPrintJITServerCHTableStats)
            JITServerHelpers::printJITServerCHTableStats(jitConfig, compInfo);

         static char *isPrintJITServerIPMsgStats = feGetEnv("TR_PrintJITServerIPMsgStats");
         if (isPrintJITServerIPMsgStats)
            {
            if (compInfo->getPersistentInfo()->getRemoteCompilationMode() == JITServer::SERVER)
               {
               TR_J9VMBase *vmj9 = (TR_J9VMBase *)TR_J9VMBase::get(context->javaVM->jitConfig, NULL);
               JITServerIProfiler *iProfiler = (JITServerIProfiler *)vmj9->getIProfiler();
               iProfiler->printStats();
               }
            }

         static char *isPrintJITServerAOTCacheStats = feGetEnv("TR_PrintJITServerAOTCacheStats");
         if (isPrintJITServerAOTCacheStats)
            {
            if (auto aotCacheMap = compInfo->getJITServerAOTCacheMap())
               aotCacheMap->printStats(stderr);
            if (auto deserializer = compInfo->getJITServerAOTDeserializer())
               deserializer->printStats(stderr);
            }

#if defined(LINUX)
         static char *isPrintJITServerMallocStats = feGetEnv("TR_PrintJITServerMallocStats");
         if (isPrintJITServerMallocStats)
            malloc_stats();
#endif /* defined(LINUX) */
         }
      }
#endif /* defined(J9VM_OPT_JITSERVER) */

   char *crashedThreadName = getOMRVMThreadName(crashedThread->omrVMThread);
   j9nls_printf(PORTLIB, J9NLS_INFO | J9NLS_STDERR, J9NLS_DMP_OCCURRED_THREAD_NAME_ID, "JIT", crashedThreadName, crashedThread);
   releaseOMRVMThreadName(crashedThread->omrVMThread);

   J9JITConfig *jitConfig = crashedThread->javaVM->jitConfig;
   if (NULL == jitConfig)
      {
      j9nls_printf(PORTLIB, J9NLS_ERROR | J9NLS_STDERR, J9NLS_DMP_ERROR_IN_DUMP_STR, "JIT", "Could not locate J9JITConfig");
      return OMR_ERROR_INTERNAL;
      }
      
   TR::CompilationInfo *compInfo = TR::CompilationInfo::get(jitConfig);
   if (NULL == compInfo)
      {
      j9nls_printf(PORTLIB, J9NLS_ERROR | J9NLS_STDERR, J9NLS_DMP_ERROR_IN_DUMP_STR, "JIT", "Could not locate TR::CompilationInfo");
      return OMR_ERROR_INTERNAL;
      }

   TR_J9VMBase *frontendOfThread = TR_J9VMBase::get(jitConfig, crashedThread);
   if (NULL == frontendOfThread)
      {
      j9nls_printf(PORTLIB, J9NLS_ERROR | J9NLS_STDERR, J9NLS_DMP_ERROR_IN_DUMP_STR, "JIT", "Could not locate TR_J9VMBase");
      return OMR_ERROR_INTERNAL;
      }

   TR::Options *options = TR::Options::getCmdLineOptions();
   if (NULL == options)
      {
      j9nls_printf(PORTLIB, J9NLS_ERROR | J9NLS_STDERR, J9NLS_DMP_ERROR_IN_DUMP_STR, "JIT", "Could not locate TR::Options");
      return OMR_ERROR_INTERNAL;
      }

   // To avoid a deadlock, release compilation monitor until we are no longer holding it
   while (compInfo->getCompilationMonitor()->owned_by_self())
      {
      compInfo->releaseCompMonitor(crashedThread);
      }

   // Release other monitors as well. In particular CHTable and classUnloadMonitor must not be held.
   while (TR::MonitorTable::get()->getClassTableMutex()->owned_by_self())
      {
      frontendOfThread->releaseClassTableMutex(false);
      }

   TR::CompilationInfoPerThread *threadCompInfo = compInfo->getCompInfoForThread(crashedThread);
   if (NULL != threadCompInfo)
      {
      TR_MethodToBeCompiled *methodBeingCompiled = threadCompInfo->getMethodBeingCompiled();

      // If we are currently compiling a method, wake everyone waiting for it to compile
      if (NULL != methodBeingCompiled && NULL != methodBeingCompiled->getMonitor())
         {
         methodBeingCompiled->getMonitor()->enter();
         methodBeingCompiled->getMonitor()->notifyAll();
         methodBeingCompiled->getMonitor()->exit();
         
         j9nls_printf(PORTLIB, J9NLS_INFO | J9NLS_STDERR, J9NLS_DMP_JIT_NOTIFIED_WAITING_THREADS);
         }

#if defined(J9VM_OPT_JITSERVER)
      if (compInfo->getPersistentInfo()->getRemoteCompilationMode() == JITServer::SERVER)
         {
         // Release the class unload RW mutex
         auto serverCompInfo = static_cast<TR::CompilationInfoPerThreadRemote *>(threadCompInfo);
         while (serverCompInfo->getClassUnloadReadMutexDepth() > 0)
            {
            serverCompInfo->getClientData()->readReleaseClassUnloadRWMutex(serverCompInfo);
            }
         }
#endif

      // Release the class unload RW mutex
      while (TR::MonitorTable::get()->getClassUnloadMonitorHoldCount(threadCompInfo->getCompThreadId()) > 0)
         {
         TR::MonitorTable::get()->readReleaseClassUnloadMonitor(threadCompInfo->getCompThreadId());
         }
      }

   TR::CompilationInfoPerThread *recompilationThreadInfo = compInfo->getCompilationInfoForDiagnosticThread();
   if (NULL == recompilationThreadInfo)
      {
      j9nls_printf(PORTLIB, J9NLS_ERROR | J9NLS_STDERR, J9NLS_DMP_ERROR_IN_DUMP_STR, "JIT", "Could not locate the diagnostic thread info");
      return OMR_ERROR_INTERNAL;
      }

   auto *recompilationThread = recompilationThreadInfo->getCompilationThread();
   if (NULL == recompilationThread)
      {
      j9nls_printf(PORTLIB, J9NLS_ERROR | J9NLS_STDERR, J9NLS_DMP_ERROR_IN_DUMP_STR, "JIT", "Could not locate the diagnostic thread");
      return OMR_ERROR_INTERNAL;
      }

   compInfo->acquireCompMonitor(crashedThread);
   compInfo->getPersistentInfo()->setDisableFurtherCompilation(true);
   compInfo->purgeMethodQueue(compilationFailure);
   compInfo->releaseCompMonitor(crashedThread);

   recompilationThreadInfo->resumeCompilationThread();

   TR::FILE *jitdumpFile = trfopen(label, "ab", false);
   if (NULL == jitdumpFile)
      {
      j9nls_printf(PORTLIB, J9NLS_ERROR | J9NLS_STDERR, J9NLS_DMP_NO_OPEN_READ, label);
      return OMR_ERROR_INTERNAL;
      }
      
   trfprintf(jitdumpFile,
      "<?xml version=\"1.0\" standalone=\"no\"?>\n"
      "<jitDump>\n"
      );

   try
      {
      // Process user defined options first. The user can specify any method signature to be recompiled at an arbitrary
      // dump event. This is typically used for debugging purposes so we process this option first if it exists.
      if (NULL != agent->dumpOptions)
         {
         const char *indexOfDot = strchr(agent->dumpOptions, '.');
         const char *indexOfParen = strchr(agent->dumpOptions, '(');

         if ((NULL != indexOfDot) && (NULL != indexOfParen))
            {
            TR::VMAccessCriticalSection findUserMethod(TR_J9VMBase::get(jitConfig, crashedThread));

            const char *className = agent->dumpOptions;
            U_32 classNameLength = static_cast<U_32>(indexOfDot - agent->dumpOptions);
            const char *methodName = indexOfDot + 1;
            U_32 methodNameLength = static_cast<U_32>(indexOfParen - methodName);
            const char *methodSig = indexOfParen;
            U_32 methodSigLength = strlen(methodSig);

            J9MethodFromSignatureWalkState state;
            J9Method *userMethod = allMethodsFromSignatureStartDo(&state, context->javaVM, 0, className, classNameLength, methodName, methodNameLength, methodSig, methodSigLength);
            while (NULL != userMethod)
               {
               J9JITExceptionTable *metadata = jitConfig->jitGetExceptionTableFromPC(crashedThread, reinterpret_cast<UDATA>(userMethod->extra));
               if (NULL != metadata)
                  {
                  auto *bodyInfo = reinterpret_cast<TR_PersistentJittedBodyInfo *>(metadata->bodyInfo);
                  if (NULL != bodyInfo)
                     {
                     if (NULL == threadCompInfo)
                        {
                        // We are an application thread
                        jitDumpRecompileWithTracing(
                           crashedThread,
                           userMethod,
                           compInfo,
                           bodyInfo->getHotness(),
                           bodyInfo->getIsProfilingBody(),
                           NULL,
                           bodyInfo->getIsAotedBody(),
                           bodyInfo->getStartPCAfterPreviousCompile(),
                           jitdumpFile
                        );
                        }
                     else
                        {
                        // We are a compilation thread

                        // See comment below for the same call on why this is needed
                        TR::CompilationInfoPerThreadBase::UninterruptibleOperation jitDumpForCrashedCompilationThread(*threadCompInfo);

                        // See comment below for the same call on why this is needed
                        TR::VMAccessCriticalSection requestSynchronousCompilation(TR_J9VMBase::get(jitConfig, crashedThread));

                        jitDumpRecompileWithTracing(
                           crashedThread,
                           userMethod,
                           compInfo,
                           bodyInfo->getHotness(),
                           bodyInfo->getIsProfilingBody(),
                           NULL,
                           bodyInfo->getIsAotedBody(),
                           bodyInfo->getStartPCAfterPreviousCompile(),
                           jitdumpFile
                        );
                        }
                     }
                  }
               userMethod = allMethodsFromSignatureNextDo(&state);
               }
            allMethodsFromSignatureEndDo(&state);
            }
         }

      if (NULL == threadCompInfo)
         {
         // We are an application thread

         if (NULL != crashedThread->gpInfo)
            {
            // The stack walker may not be able to walk the stack if the crash did not happen on a transition frame. In
            // such cases the stack walker will resume walking the stack on the last known valid point, which will be a
            // transition frame further up the stack (ex. INT -> JIT transition frame). This will result in the stack
            // walker potentially skipping some JIT methods on the backtrace. This is not desirable. Chances are high
            // that the crash happen because of a miscompilation in the first JIT compiled method on the stack, so it
            // is imperative that we recompile the method we actually crashed in.
            const char *name;
            void *value;
            U_32 infoType = j9sig_info(crashedThread->gpInfo, J9PORT_SIG_CONTROL, J9PORT_SIG_CONTROL_PC, &name, &value);

            if (J9PORT_SIG_VALUE_ADDRESS == infoType)
               {
               J9JITExceptionTable *metadata = jitConfig->jitGetExceptionTableFromPC(crashedThread, *reinterpret_cast<UDATA*>(value));
               if (NULL != metadata)
                  {
                  auto *bodyInfo = reinterpret_cast<TR_PersistentJittedBodyInfo *>(metadata->bodyInfo);
                  if (NULL != bodyInfo)
                     {
                     jitDumpRecompileWithTracing(
                        crashedThread,
                        metadata->ramMethod,
                        compInfo,
                        bodyInfo->getHotness(),
                        bodyInfo->getIsProfilingBody(),
                        NULL,
                        bodyInfo->getIsAotedBody(),
                        bodyInfo->getStartPCAfterPreviousCompile(),
                        jitdumpFile
                     );
                     }
                  }
               }
            }

         J9StackWalkState walkState;
         walkState.userData1 = compInfo;
         walkState.userData2 = jitdumpFile;
         walkState.walkThread = crashedThread;
         walkState.skipCount = 0;
         walkState.maxFrames = 16;
         walkState.flags = (
            J9_STACKWALK_VISIBLE_ONLY |
            J9_STACKWALK_SKIP_INLINES |
            J9_STACKWALK_COUNT_SPECIFIED |
            J9_STACKWALK_ITERATE_FRAMES |
            J9_STACKWALK_NO_ERROR_REPORT
            );
         walkState.frameWalkFunction = jitDumpStackFrameIterator;

         crashedThread->javaVM->walkStackFrames(crashedThread, &walkState);
         }
      else
         {
         // We are a compilation thread

         // Printing the crashed thread trees or any similar operation on the crashed thread may result in having to
         // acquire VM access (ex. to get a class signature). Other VM events, such as VM shutdown or the GC unloading
         // classes may cause compilations to be interrupted. Because the crashed thread is not a diagnostic thread,
         // the call to print the crashed thread IL may get interrupted and the jitdump will be incomplete. We prevent
         // this from occuring by disallowing interruptions until we are done generating the jitdump.
         TR::CompilationInfoPerThreadBase::UninterruptibleOperation jitDumpForCrashedCompilationThread(*threadCompInfo);

         TR::Compilation *comp = threadCompInfo->getCompilation();
         if (NULL == comp)
            {
            j9nls_printf(PORTLIB, J9NLS_ERROR | J9NLS_STDERR, J9NLS_DMP_ERROR_IN_DUMP_STR, "JIT", "Could not locate the compilation object");
            trfclose(jitdumpFile);
            return OMR_ERROR_INTERNAL;
            }

#if defined(J9VM_OPT_JITSERVER)
         if (comp->isOutOfProcessCompilation())
            {
            // Inform the client that JitDump has started and is about to trace IL of the crashed thread
            TR_MethodToBeCompiled *entry = threadCompInfo->getMethodBeingCompiled();
            JITServer::ServerStream *stream = entry->_stream;
            stream->write(JITServer::MessageType::jitDumpPrintIL, JITServer::Void());
            stream->read<JITServer::Void>();
            }
#endif

         traceILOfCrashedThread(crashedThread, comp, jitdumpFile);

         TR_MethodToBeCompiled *methodBeingCompiled = threadCompInfo->getMethodBeingCompiled();
         if (NULL != methodBeingCompiled && methodBeingCompiled->getMethodDetails().isOrdinaryMethod())
            {
            j9nls_printf(PORTLIB, J9NLS_INFO | J9NLS_STDERR, J9NLS_DMP_JIT_ORDINARY_METHOD);

               {
               // The current thread is a compilation thread which may or may not currently hold VM access. The request
               // for recompilation to generate the jitdump will be performed synchronously for which the code path we
               // will take will be the same as if we were an application thread. We will take the synchronous request
               // path in `compileOnSeparateThread` which ends up releasing VM access prior to waiting on the diagnostic
               // thread to finish the queued compile. To avoid deadlocks we must acquire VM access here.
               TR::VMAccessCriticalSection requestSynchronousCompilation(TR_J9VMBase::get(jitConfig, crashedThread));

               // request the compilation
               jitDumpRecompileWithTracing(
                  crashedThread,
                  (J9Method *)(comp->getMethodBeingCompiled()->getPersistentIdentifier()),
                  compInfo,
                  (TR_Hotness)comp->getOptLevel(),
                  comp->isProfilingCompilation(),
                  comp->getOptions(),
                  comp->compileRelocatableCode(),
                  methodBeingCompiled->_oldStartPC,
                  jitdumpFile
               );
               }
            }
         }
      }
   catch (const std::exception &e)
      {
      const char *exceptionName;

#if defined(J9ZOS390)
      // Compiling with -Wc,lp64 results in a crash on z/OS when trying
      // to call the what() virtual method of the exception.
      exceptionName = "std::exception";
#else
      exceptionName = e.what();
#endif

      trfprintf(jitdumpFile, "\n=== EXCEPTION THROWN (%s) ===\n", exceptionName);
      }

   trfprintf(jitdumpFile, "</jitDump>\n");
   trfflush(jitdumpFile);
   trfclose(jitdumpFile);

   recompilationThreadInfo->suspendCompilationThread();

   compInfo->getPersistentInfo()->setDisableFurtherCompilation(false);

   return OMR_ERROR_NONE;
   }