[ORC] Make the VModuleKey optional, propagate it via MaterializationUnit and

MaterializationResponsibility.

VModuleKeys are intended to enable selective removal of modules from a JIT
session, however for a wide variety of use cases selective removal is not
needed and introduces unnecessary overhead. As of this commit, the default
constructed VModuleKey value is reserved as a "do not track" value, and
becomes the default when adding a new module to the JIT.

This commit also changes the propagation of VModuleKeys. They were passed
alongside the MaterializationResponsibity instance in XXLayer::emit methods,
but are now propagated as part of the MaterializationResponsibility instance
itself (and as part of MaterializationUnit when stored in a JITDylib).
Associating VModuleKeys with MaterializationUnits in this way should allow
for a thread-safe module removal mechanism in the future, even when a module
is in the process of being compiled, by having the
MaterializationResponsibility object check in on its VModuleKey's state
before commiting its results to the JITDylib.

llvm-svn: 344643

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/ExecutionEngine/Orc/ObjectTransformLayer.cpp b/llvm/lib/ExecutionEngine/Orc/ObjectTransformLayer.cpp
index 0be23f2..825f532 100644
--- a/llvm/lib/ExecutionEngine/Orc/ObjectTransformLayer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/ObjectTransformLayer.cpp
@@ -18,12 +18,12 @@ ObjectTransformLayer::ObjectTransformLayer(ExecutionSession &ES,
                                             TransformFunction Transform)
     : ObjectLayer(ES), BaseLayer(BaseLayer), Transform(std::move(Transform)) {}
 
-void ObjectTransformLayer::emit(MaterializationResponsibility R, VModuleKey K,
+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(K), std::move(*TransformedObj));
+    BaseLayer.emit(std::move(R), std::move(*TransformedObj));
   else {
     R.failMaterialization();
     getExecutionSession().reportError(TransformedObj.takeError());