Fix race condition in jump table list creation

src/IceCfg.cpp

 //===- subzero/src/IceCfg.cpp - Control flow graph implementation ---------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 948 matching lines @@
 
 void Cfg::emitJumpTables() {
   switch (Ctx->getFlags().getOutFileType()) {
   case FT_Elf:
   case FT_Iasm: {
     // The emission needs to be delayed until the after the text section so
     // save the offsets in the global context.
     IceString MangledName = Ctx->mangleName(getFunctionName());
     for (const InstJumpTable *JumpTable : JumpTables) {
       SizeT NumTargets = JumpTable->getNumTargets();
-      JumpTableData &JT =
-          Ctx->addJumpTable(MangledName, JumpTable->getId(), NumTargets);
+      JumpTableData::TargetList TargetList;
       for (SizeT I = 0; I < NumTargets; ++I) {
         SizeT Index = JumpTable->getTarget(I)->getIndex();
-        JT.pushTarget(getAssembler()->getCfgNodeLabel(Index)->getPosition());
+        TargetList.emplace_back(
+            getAssembler()->getCfgNodeLabel(Index)->getPosition());
       }
+      Ctx->addJumpTable(MangledName, JumpTable->getId(), TargetList);
     }
   } break;
   case FT_Asm: {
     // Emit the assembly directly so we don't need to hang on to all the names
     for (const InstJumpTable *JumpTable : JumpTables)
       getTarget()->emitJumpTable(this, JumpTable);
   } break;
   }
 }
 
@@ skipping 104 matching lines @@
     }
   }
   // Print each basic block
   for (CfgNode *Node : Nodes)
     Node->dump(this);
   if (isVerbose(IceV_Instructions))
     Str << "}\n";
 }
 
 } // end of namespace Ice