[mlir] Add nano precision clock to execution engine

[nicolasvasilache]

Cool, this was long needed, thanks for the addition!

[shabalin]

Add [mlir] prefix to the commit message

[jpienaar]

This seems to be causing build bot failure

mlir/lib/ExecutionEngine/RunnerUtils.cpp

 //===- RunnerUtils.cpp - Utils for MLIR exec on targets with a C++ runtime ===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements basic functions to debug structured MLIR types at
 // runtime. Entities in this file may not be compatible with targets without a
 // C++ runtime. These may be progressively migrated to CRunnerUtils.cpp over
 // time.
 //
 //===----------------------------------------------------------------------===//
 
 #include "mlir/ExecutionEngine/RunnerUtils.h"
+#include <chrono>
 
 extern "C" void
 _mlir_ciface_print_memref_shape_i8(UnrankedMemRefType<int8_t> *M) {
   std::cout << "Unranked Memref ";
   printMemRefMetaData(std::cout, DynamicMemRefType<int8_t>(*M));
   std::cout << "\n";
 }
 

 extern "C" void _mlir_ciface_print_memref_f32(UnrankedMemRefType<float> *M) {
   impl::printMemRef(*M);
 }
 
 extern "C" void _mlir_ciface_print_memref_f64(UnrankedMemRefType<double> *M) {
   impl::printMemRef(*M);
 }
 
+extern "C" int64_t _mlir_ciface_nano_time() {
+  auto now = std::chrono::high_resolution_clock::now();
+  auto duration = now.time_since_epoch();
+  auto nanoseconds =
+      std::chrono::duration_cast<std::chrono::nanoseconds>(duration);
+  return nanoseconds.count();
+}
+
 extern "C" void print_memref_i32(int64_t rank, void *ptr) {
   UnrankedMemRefType<int32_t> descriptor = {rank, ptr};
   _mlir_ciface_print_memref_i32(&descriptor);
 }
 
 extern "C" void print_memref_i64(int64_t rank, void *ptr) {
   UnrankedMemRefType<int64_t> descriptor = {rank, ptr};
   _mlir_ciface_print_memref_i64(&descriptor);

mlir/test/python/execution_engine.py

execution_engine = ExecutionEngine(
             "../../../../lib/libmlir_c_runner_utils.so"
         ])
     execution_engine.invoke("main", arg0_memref_ptr)
     # CHECK: Unranked Memref
     # CHECK-NEXT: [42]
 
 
 run(testSharedLibLoad)
+
+
+#  Test that nano time clock is available.
+# CHECK-LABEL: TEST: testNanoTime
+def testNanoTime():
+  with Context():
+    module = Module.parse("""
+      module {
+      func @main() attributes { llvm.emit_c_interface } {
+        %now = call @nano_time() : () -> i64
+        %memref = memref.alloca() : memref<1xi64>
+        %c0 = arith.constant 0 : index
+        memref.store %memref[%c0] : memref<1xi64>
+        call @print_memref_i64(%memref) : (memref<*xi64) -> ()
+        return
+      }
+      func private @nano_time() -> i64 attributes { llvm.emit_c_interface }
+      func private @print_memref_i64(memref<*xi64>) attributes { llvm.emit_c_interface }
+    }""")
+
+    execution_engine = ExecutionEngine(
+        lowerToLLVM(module),
+        opt_level=3,
+        shared_libs=[
+            "../../../../lib/libmlir_runner_utils.so",
+            "../../../../lib/libmlir_c_runner_utils.so"
+        ])
+    execution_engine.invoke("main", arg0_memref_ptr)
+    # CHECK: Unranked Memref
+    # CHECK: [{{.*}}]
+
+
+run(testNanoTime)