Add a simple arity-agnostic invocation of JIT-compiled functions.

This is useful to call generic function with unspecified number of arguments
e.g. when interfacing with ML frameworks.

PiperOrigin-RevId: 230974736

mlir/include/mlir/ExecutionEngine/ExecutionEngine.h

@@ -67,6 +67,11 @@ public:
   template <typename... Args>
   llvm::Error invoke(StringRef name, Args &... args);
 
+  /// Invokes the function with the given name passing it the list of arguments
+  /// as a list of opaque pointers. This is the arity-agnostic equivalent of
+  /// the templated `invoke`.
+  llvm::Error invoke(StringRef name, MutableArrayRef<void *> args);
+
 private:
   // Private implementation of the JIT (PIMPL)
   std::unique_ptr<impl::OrcJIT> jit;

mlir/lib/ExecutionEngine/ExecutionEngine.cpp

@@ -295,3 +295,15 @@ Expected<void (*)(void **)> ExecutionEngine::lookup(StringRef name) const {
     return make_string_error("looked up function is null");
   return fptr;
 }
+
+llvm::Error ExecutionEngine::invoke(StringRef name,
+                                    MutableArrayRef<void *> args) {
+  auto expectedFPtr = lookup(name);
+  if (!expectedFPtr)
+    return expectedFPtr.takeError();
+  auto fptr = *expectedFPtr;
+
+  (*fptr)(args.data());
+
+  return llvm::Error::success();
+}