Express ownership transfer in PassManager API through std::unique_ptr (NFC)

Since raw pointers are always passed around for IR construct without
implying any ownership transfer, it can be error prone to have implicit
ownership transferred the same way.
For example this code can seem harmless:

  Pass *pass = ....
  pm.addPass(pass);
  pm.addPass(pass);
  pm.run(module);

PiperOrigin-RevId: 263053082

1 files changed, 6 insertions, 5 deletions

diff --git a/mlir/lib/Conversion/LoopsToGPU/LoopsToGPUPass.cpp b/mlir/lib/Conversion/LoopsToGPU/LoopsToGPUPass.cpp
index 7c785b5c995..36869b87f1a 100644
--- a/mlir/lib/Conversion/LoopsToGPU/LoopsToGPUPass.cpp
+++ b/mlir/lib/Conversion/LoopsToGPU/LoopsToGPUPass.cpp
@@ -66,13 +66,14 @@ struct ForLoopMapper : public FunctionPass<ForLoopMapper> {
 };
 } // namespace
 
-FunctionPassBase *mlir::createSimpleLoopsToGPUPass(unsigned numBlockDims,
-                                                   unsigned numThreadDims) {
-  return new ForLoopMapper(numBlockDims, numThreadDims);
+std::unique_ptr<FunctionPassBase>
+mlir::createSimpleLoopsToGPUPass(unsigned numBlockDims,
+                                 unsigned numThreadDims) {
+  return llvm::make_unique<ForLoopMapper>(numBlockDims, numThreadDims);
 }
 
 static PassRegistration<ForLoopMapper>
     registration(PASS_NAME, "Convert top-level loops to GPU kernels", [] {
-      return new ForLoopMapper(clNumBlockDims.getValue(),
-                               clNumThreadDims.getValue());
+      return llvm::make_unique<ForLoopMapper>(clNumBlockDims.getValue(),
+                                              clNumThreadDims.getValue());
     });