[llvm] [mlir][Transform] Create a transform interpreter and a preloader pass (PR #68661)

[Nicolas Vasilache via llvm-commits]

================
@@ -91,10 +145,51 @@ transform::detail::findTransformEntryPoint(Operation *root, ModuleOp module,
   return nullptr;
 }
 
-/// Return whether `func1` can be merged into `func2`. For that to work `func1`
-/// has to be a declaration (aka has to be external) and `func2` either has to
-/// be a declaration as well, or it has to be public (otherwise, it wouldn't
-/// be visible by `func1`).
+LogicalResult transform::detail::assembleTransformLibraryFromPaths(
+    MLIRContext *context, ArrayRef<std::string> transformLibraryPaths,
+    OwningOpRef<ModuleOp> &transformModule) {
+  // Assemble list of library files.
+  SmallVector<std::string> libraryFileNames;
+  if (failed(detail::expandPathsToMLIRFiles(transformLibraryPaths, context,
+                                            libraryFileNames)))
+    return failure();
+
+  // Parse modules from library files.
+  SmallVector<OwningOpRef<ModuleOp>> parsedLibraries;
+  for (const std::string &libraryFileName : libraryFileNames) {
+    OwningOpRef<ModuleOp> parsedLibrary;
+    auto loc = FileLineColLoc::get(context, libraryFileName, 0, 0);
+    if (failed(transform::detail::parseTransformModuleFromFile(
+            context, libraryFileName, parsedLibrary)))
+      return emitError(loc) << "failed to parse transform library module";
+    parsedLibraries.push_back(std::move(parsedLibrary));
+  }
+
+  // Merge parsed libraries into one module.
----------------
nicolasvasilache wrote:

Good point, in this PR I am just moving some code around, can we keep this for a followup cleanup?

https://github.com/llvm/llvm-project/pull/68661