[OpenMP] Fix seg fault in libomptarget when using Info with multiple threads

[jhuber6]

Summary

One option for the LIBOMPTARGET_INFO environment variable is to print the current status of the device's data mappings. These are a shared resource among threads so this needs to be protected when using multiple streams.

[jdoerfert]

LG

[JonChesterfield]

openmp/libomptarget/src/private.h

112

Is this stuff built with exceptions disabled? Used to seeing unlock() called from destructors.

[jhuber6]

openmp/libomptarget/src/private.h

112

This is the same thing that the Device type uses to protect the data mapping when it adds or removes something so I'm assuming it's compatible.

[jdoerfert]

openmp/libomptarget/src/private.h

112

I highly doubt the runtime can recover from exceptions right now anyway.

openmp/libomptarget/src/interface.cpp

case tgt_disabled:
     break;
   case tgt_default:
     FATAL_MESSAGE0(1, "default offloading policy must be switched to "
                       "mandatory or disabled");
     break;
   case tgt_mandatory:
     if (!success) {
       if (getInfoLevel() & OMP_INFOTYPE_DUMP_TABLE)
-        for (const auto &Device : PM->Devices)
+        for (auto &Device : PM->Devices)
           dumpTargetPointerMappings(loc, Device);
       else
         FAILURE_MESSAGE("Run with LIBOMPTARGET_DEBUG=%d to dump host-target "
                         "pointer mappings.\n",
                         OMP_INFOTYPE_DUMP_TABLE);
 
       SourceInfo info(loc);
       if (info.isAvailible())
         fprintf(stderr, "%s:%d:%d: ", info.getFilename(), info.getLine(),
                 info.getColumn());
       else
         FAILURE_MESSAGE("Source location information not present. Compile with "
                         "-g or -gline-tables-only.\n");
       FATAL_MESSAGE0(
           1, "failure of target construct while offloading is mandatory");
     } else {
       if (getInfoLevel() & OMP_INFOTYPE_DUMP_TABLE)
-        for (const auto &Device : PM->Devices)
+        for (auto &Device : PM->Devices)
           dumpTargetPointerMappings(loc, Device);
     }
     break;
   }
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 /// adds requires flags

openmp/libomptarget/src/private.h

 #endif
 
 #define TARGET_NAME Libomptarget
 #define DEBUG_PREFIX GETNAME(TARGET_NAME)
 
 ////////////////////////////////////////////////////////////////////////////////
 /// dump a table of all the host-target pointer pairs on failure
 static inline void dumpTargetPointerMappings(const ident_t *Loc,
-                                             const DeviceTy &Device) {
+                                             DeviceTy &Device) {
   if (Device.HostDataToTargetMap.empty())
     return;
 
   SourceInfo Kernel(Loc);
   INFO(OMP_INFOTYPE_ALL, Device.DeviceID,
        "OpenMP Host-Device pointer mappings after block at %s:%d:%d:\n",
        Kernel.getFilename(), Kernel.getLine(), Kernel.getColumn());
   INFO(OMP_INFOTYPE_ALL, Device.DeviceID, "%-18s %-18s %s %s %s\n", "Host Ptr",
        "Target Ptr", "Size (B)", "RefCount", "Declaration");
+  Device.DataMapMtx.lock();
   for (const auto &HostTargetMap : Device.HostDataToTargetMap) {
     SourceInfo Info(HostTargetMap.HstPtrName);
     INFO(OMP_INFOTYPE_ALL, Device.DeviceID,
          DPxMOD " " DPxMOD " %-8" PRIuPTR " %-8" PRId64 " %s at %s:%d:%d\n",
          DPxPTR(HostTargetMap.HstPtrBegin), DPxPTR(HostTargetMap.TgtPtrBegin),
          HostTargetMap.HstPtrEnd - HostTargetMap.HstPtrBegin,
          HostTargetMap.getRefCount(), Info.getName(), Info.getFilename(),
          Info.getLine(), Info.getColumn());
   }
+  Device.DataMapMtx.unlock();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 /// Print out the names and properties of the arguments to each kernel
 static inline void
 printKernelArguments(const ident_t *Loc, const int64_t DeviceId,
                      const int32_t ArgNum, const int64_t *ArgSizes,
                      const int64_t *ArgTypes, const map_var_info_t *ArgNames,