[ORC] Work around AIX build compiler: Replace lambda; NFC

[hubert.reinterpretcast]

Summary

By replacing a lambda expression with a functor class instance, this
patch works around an issue encountered on AIX where the IBM XL compiler
appears to make no progress for many hours.

[jsji]

LGTM to unblock the buildbots first. Thanks for the workaround.

[jsji]

llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp

449

Please keep this FIXME.

[hubert.reinterpretcast]

llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp

449

Good catch. Will do.

[lhames]

llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp

468–479

Is there a bug filed against the AIX compiler that we could cite here?

In any case, please add a comment explaining that this was broken out due to an AIX compiler bug, and should be turned back into a lambda once the bug is fixed.

Otherwise LGTM.

[lhames]

llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp

467

Somehow I missed this. ;)

If there's a bug number for that it would be good to include it, otherwise everything's good to go. :)

[hubert.reinterpretcast]

llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp

467

Thanks @lhames. We have a bug number (168299) in an internal bug tracker. Since it is not accessible to most people, I think it is better to omit it from the code comment.

llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp

LLVM_DEBUG({
              << formatv("{0:x}", Handle.getValue()) << "\n";
     });
     SendResult(make_error<StringError>("No JITDylib associated with handle " +
                                            formatv("{0:x}", Handle.getValue()),
                                        inconvertibleErrorCode()));
     return;
   }
 
+  // Use functor class to work around XL build compiler issue on AIX.
+  class RtLookupNotifyComplete {
+  public:
+    RtLookupNotifyComplete(SendSymbolAddressFn &&SendResult)
+        : SendResult(std::move(SendResult)) {}
+    void operator()(Expected<SymbolMap> Result) {
+      if (Result) {
+        assert(Result->size() == 1 && "Unexpected result map count");
+        SendResult(ExecutorAddress(Result->begin()->second.getAddress()));
+      } else {
+        SendResult(Result.takeError());
+      }
+    }
+
+  private:
+    SendSymbolAddressFn SendResult;
+  };
+
   // FIXME: Proper mangling.
   auto MangledName = ("_" + SymbolName).str();
   ES.lookup(
       LookupKind::DLSym, {{JD, JITDylibLookupFlags::MatchExportedSymbolsOnly}},
       SymbolLookupSet(ES.intern(MangledName)), SymbolState::Ready,
-      [SendResult = std::move(SendResult)](Expected<SymbolMap> Result) mutable {
-        if (Result) {
-          assert(Result->size() == 1 && "Unexpected result map count");
-          SendResult(ExecutorAddress(Result->begin()->second.getAddress()));
-        } else
-          SendResult(Result.takeError());
-      },
-      NoDependenciesToRegister);
+      RtLookupNotifyComplete(std::move(SendResult)), NoDependenciesToRegister);
 }
 
 Error MachOPlatform::bootstrapMachORuntime(JITDylib &PlatformJD) {
 
   std::pair<const char *, ExecutorAddress *> Symbols[] = {
       {"___orc_rt_macho_platform_bootstrap", &orc_rt_macho_platform_bootstrap},
       {"___orc_rt_macho_platform_shutdown", &orc_rt_macho_platform_shutdown},
       {"___orc_rt_macho_register_object_sections",
        &orc_rt_macho_register_object_sections}};
 
   SymbolLookupSet RuntimeSymbols;
   std::vector<std::pair<SymbolStringPtr, ExecutorAddress *>> AddrsToRecord;
   for (const auto &KV : Symbols) {
     auto Name = ES.intern(KV.first);
     RuntimeSymbols.add(Name);