[ORC] Add a utility to support dumping JIT'd objects to disk for debugging.

Adds a DumpObjects utility that can be used to dump JIT'd objects to disk.
Instances of DebugObjects may be used by ObjectTransformLayer as no-op
transforms.

This patch also adds an ObjectTransformLayer to LLJIT and an example of how
to use this utility to dump JIT'd objects in LLJIT.

1 files changed, 11 insertions, 5 deletions

diff --git a/llvm/lib/ExecutionEngine/Orc/ObjectTransformLayer.cpp b/llvm/lib/ExecutionEngine/Orc/ObjectTransformLayer.cpp
index 8155173..d18eb38 100644
--- a/llvm/lib/ExecutionEngine/Orc/ObjectTransformLayer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/ObjectTransformLayer.cpp
@@ -21,12 +21,18 @@ void ObjectTransformLayer::emit(MaterializationResponsibility R,
                                 std::unique_ptr<MemoryBuffer> O) {
   assert(O && "Module must not be null");
 
-  if (auto TransformedObj = Transform(std::move(O)))
-    BaseLayer.emit(std::move(R), std::move(*TransformedObj));
-  else {
-    R.failMaterialization();
-    getExecutionSession().reportError(TransformedObj.takeError());
+  // If there is a transform set then apply it.
+  if (Transform) {
+    if (auto TransformedObj = Transform(std::move(O)))
+      O = std::move(*TransformedObj);
+    else {
+      R.failMaterialization();
+      getExecutionSession().reportError(TransformedObj.takeError());
+      return;
+    }
   }
+
+  BaseLayer.emit(std::move(R), std::move(O));
 }
 
 } // End namespace orc.