Add VmModule.mmap() to Python API. (iree-org#14124)

We really need page aligned flatbuffer blobs vs normal malloc alignment.
The best way to be loading a file is via mmap, so just make that
available as an API.

This could be done in Python by the caller but is error-prone. The
public API will make this more robust.

Provides the mechanism to fix iree-org#13887

runtime/bindings/python/tests/vm_test.py

@@ -8,6 +8,7 @@
 
 import logging
 import numpy as np
+import tempfile
 import unittest
 
 import iree.compiler
@@ -106,6 +107,27 @@ def test_add_scalar_new_abi(self):
     logging.info("result: %s", result)
     self.assertEqual(result, 11)
 
+  def test_mmap(self):
+    binary = iree.compiler.compile_str(
+        """
+        func.func @add_scalar(%arg0: i32, %arg1: i32) -> i32 {
+          %0 = arith.addi %arg0, %arg1 : i32
+          return %0 : i32
+        }
+        """,
+        target_backends=iree.compiler.core.DEFAULT_TESTING_BACKENDS)
+    with tempfile.NamedTemporaryFile() as tf:
+      tf.write(binary)
+      tf.flush()
+      m = iree.runtime.VmModule.mmap(self.instance, tf.name)
+      context = iree.runtime.VmContext(self.instance,
+                                       modules=[self.hal_module, m])
+      f = m.lookup_function("add_scalar")
+      finv = iree.runtime.FunctionInvoker(context, self.device, f, tracer=None)
+      result = finv(5, 6)
+      logging.info("result: %s", result)
+      self.assertEqual(result, 11)
+
   def test_synchronous_dynamic_shape_invoke_function_new_abi(self):
     m = create_simple_dynamic_abs_module(self.instance)
     context = iree.runtime.VmContext(self.instance,

runtime/bindings/python/vm.cc

@@ -150,6 +150,23 @@ VmModule VmModule::ResolveModuleDependency(VmInstance* instance,
   return py_module;
 }
 
+VmModule VmModule::MMap(VmInstance* instance, std::string filepath) {
+  IREE_TRACE_SCOPE_NAMED("VmModule::MMap");
+  auto mmap_module = py::module::import("mmap");
+  auto open_func = py::module::import("io").attr("open");
+  auto file_obj = open_func(filepath, "r+b");
+  auto flags = py::cast<int64_t>(mmap_module.attr("MAP_SHARED"));
+  // MAP_POPULATE isn't available on all versions/platforms.
+  if (py::hasattr(mmap_module, "MAP_POPULATE")) {
+    flags |= py::cast<int64_t>(mmap_module.attr("MAP_POPULATE"));
+  }
+  auto prot = py::cast<int64_t>(mmap_module.attr("PROT_READ"));
+  auto mapped_file =
+      mmap_module.attr("mmap")(file_obj.attr("fileno")(), 0, flags, prot);
+  mapped_file.attr("madvise")(mmap_module.attr("MADV_RANDOM"));
+  return FromFlatbufferBlob(instance, mapped_file);
+}
+
 VmModule VmModule::FromFlatbufferBlob(VmInstance* instance,
                                       py::object flatbuffer_blob_object) {
   IREE_TRACE_SCOPE_NAMED("VmModule::FromFlatbufferBlob");
@@ -661,6 +678,7 @@ void SetupVmBindings(pybind11::module m) {
       .def_static("resolve_module_dependency",
                   &VmModule::ResolveModuleDependency)
       .def_static("from_flatbuffer", &VmModule::FromFlatbufferBlob)
+      .def_static("mmap", &VmModule::MMap)
       .def_property_readonly("name", &VmModule::name)
       .def_property_readonly("version",
                              [](VmModule& self) {

runtime/bindings/python/vm.h

@@ -133,6 +133,7 @@ class VmModule : public ApiRefCounted<VmModule, iree_vm_module_t> {
                                           const std::string& name,
                                           uint32_t minimum_version);
 
+  static VmModule MMap(VmInstance* instance, std::string filepath);
   static VmModule FromFlatbufferBlob(VmInstance* instance,
                                      py::object flatbuffer_blob_object);