[compiler-rt] [llvm] [ORC][Runtime] Add `dlupdate` for MachO (PR #97441)

[Matheus Izvekov via llvm-commits]

================
@@ -1236,6 +1258,68 @@ Error MachOPlatformRuntimeState::dlopenInitialize(
   return Error::success();
 }
 
+Expected<void *> MachOPlatformRuntimeState::dlupdateImpl(void *DSOHandle,
+                                                         int Mode) {
+  std::unique_lock<std::mutex> Lock(JDStatesMutex);
+
+  // Try to find JITDylib state by DSOHandle.
+  auto *JDS = getJITDylibStateByHeader(DSOHandle);
+
+  if (!JDS) {
+    std::ostringstream ErrStream;
+    ErrStream << "No registered JITDylib for " << DSOHandle;
+    return make_error<StringError>(ErrStream.str());
+  }
+
+  if (!JDS->referenced())
+    return make_error<StringError>("dlupdate failed, JITDylib must be open.");
+
+  if (!JDS->Sealed) {
+    if (auto Err = dlupdateFull(Lock, *JDS))
+      return std::move(Err);
+  }
+
+  // Return the header address.
+  return JDS->Header;
+}
+
+Error MachOPlatformRuntimeState::dlupdateFull(
+    std::unique_lock<std::mutex> &JDStatesLock, JITDylibState &JDS) {
+  // Call back to the JIT to push the initializers.
+  Expected<MachOJITDylibDepInfoMap> DepInfo((MachOJITDylibDepInfoMap()));
+  // Unlock so that we can accept the initializer update.
+  JDStatesLock.unlock();
+  if (auto Err = WrapperFunction<SPSExpected<SPSMachOJITDylibDepInfoMap>(
+          SPSExecutorAddr)>::call(&__orc_rt_macho_push_initializers_tag,
+                                  DepInfo, ExecutorAddr::fromPtr(JDS.Header)))
+    return Err;
+  JDStatesLock.lock();
----------------
mizvekov wrote:

Is it ok to leave JDStatesLock unlocked in this error path?

https://github.com/llvm/llvm-project/pull/97441