[Orc] Fix race condition in DebugObjectManagerPlugin

During finalization the debug object is registered with the target. Materialization must wait for this process to finish. Otherwise we might start running code before the debugger finished processing the corresponding debug info.

Reviewed By: lhames

Differential Revision: https://reviews.llvm.org/D98417

diff --git a/llvm/lib/ExecutionEngine/Orc/DebugObjectManagerPlugin.cpp b/llvm/lib/ExecutionEngine/Orc/DebugObjectManagerPlugin.cpp
index 6909928..1da87dd 100644 (file)
--- a/llvm/lib/ExecutionEngine/Orc/DebugObjectManagerPlugin.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/DebugObjectManagerPlugin.cpp
@@ -18,6 +18,7 @@
 #include "llvm/Object/ELFObjectFile.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Errc.h"
+#include "llvm/Support/MSVCErrorWorkarounds.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/raw_ostream.h"
@@ -463,26 +464,38 @@ Error DebugObjectManagerPlugin::notifyEmitted(
   DebugObject *UnownedDebugObj = It->second.release();
   PendingObjs.erase(It);
 
+  // During finalization the debug object is registered with the target.
+  // Materialization must wait for this process to finish. Otherwise we might
+  // start running code before the debugger processed the corresponding debug
+  // info.
+  std::promise<MSVCPError> FinalizePromise;
+  std::future<MSVCPError> FinalizeErr = FinalizePromise.get_future();
+
   // FIXME: We released ownership of the DebugObject, so we can easily capture
   // the raw pointer in the continuation function, which re-owns it immediately.
   if (UnownedDebugObj)
     UnownedDebugObj->finalizeAsync(
-        [this, Key, UnownedDebugObj](Expected<sys::MemoryBlock> TargetMem) {
+        [this, Key, UnownedDebugObj,
+         &FinalizePromise](Expected<sys::MemoryBlock> TargetMem) {
           std::unique_ptr<DebugObject> ReownedDebugObj(UnownedDebugObj);
           if (!TargetMem) {
-            ES.reportError(TargetMem.takeError());
+            FinalizePromise.set_value(TargetMem.takeError());
             return;
           }
           if (Error Err = Target->registerDebugObject(*TargetMem)) {
-            ES.reportError(std::move(Err));
+            FinalizePromise.set_value(std::move(Err));
             return;
           }
 
+          // Registration successful, notifyEmitted() can return now and
+          // materialization can finish.
+          FinalizePromise.set_value(Error::success());
+
           std::lock_guard<std::mutex> Lock(RegisteredObjsLock);
           RegisteredObjs[Key].push_back(std::move(ReownedDebugObj));
         });
 
-  return Error::success();
+  return FinalizeErr.get();
 }
 
 Error DebugObjectManagerPlugin::notifyFailed(