Add compiler timing diagnostics to mjsCompiler, printed by compile.cc

For example, `compile mujoco_menagerie/robotis_op3/scene.xml` now outputs

```
Compile 1 (cold cache):
  total:      317.2 ms
  assets:     284.8 ms (wall clock)
    load:     616.1 ms
    hull:      26.4 ms
    poly:     137.8 ms
    inert:    177.8 ms
    bvh:      568.2 ms
    octr:       1.6 ms
    tex:       25.3 ms
  other:       32.4 ms

Compile 2 (warm cache):
  total:       79.9 ms
  assets:      54.5 ms (wall clock)
    load:     888.5 ms
    hull:       0.0 ms
    poly:       0.0 ms
    inert:      0.0 ms
    bvh:        0.0 ms
    octr:       0.0 ms
    tex:       21.4 ms
  other:       25.3 ms
```

PiperOrigin-RevId: 917850214
Change-Id: Iaec86230bec0faf2e47820e20cbff61de5b2621e

python/mujoco/introspect/enums.py

@@ -718,6 +718,23 @@ ENUMS: Mapping[str, EnumDecl] = dict([
              ('mjORIENTATION_EULER', 4),
          ]),
      )),
+    ('mjtCTimer',
+     EnumDecl(
+         name='mjtCTimer',
+         declname='enum mjtCTimer_',
+         values=dict([
+             ('mjCTIMER_TOTAL', 0),
+             ('mjCTIMER_ASSETS', 1),
+             ('mjCTIMER_TEXTURE', 2),
+             ('mjCTIMER_MESH_LOAD', 3),
+             ('mjCTIMER_MESH_HULL', 4),
+             ('mjCTIMER_MESH_POLYGON', 5),
+             ('mjCTIMER_MESH_INERTIA', 6),
+             ('mjCTIMER_MESH_BVH', 7),
+             ('mjCTIMER_MESH_OCTREE', 8),
+             ('mjNCTIMER', 9),
+         ]),
+     )),
     ('mjtCatBit',
      EnumDecl(
          name='mjtCatBit',

python/mujoco/introspect/functions.py

@@ -6471,6 +6471,22 @@ FUNCTIONS: Mapping[str, FunctionDecl] = dict([
          ),
          doc='Get compiler error message from spec.',
      )),
+    ('mjs_getTimer',
+     FunctionDecl(
+         name='mjs_getTimer',
+         return_type=PointerType(
+             inner_type=ValueType(name='double', is_const=True),
+         ),
+         parameters=(
+             FunctionParameterDecl(
+                 name='s',
+                 type=PointerType(
+                     inner_type=ValueType(name='mjSpec'),
+                 ),
+             ),
+         ),
+         doc='Get compiler timing diagnostics from spec, returns pointer to array of size mjNCTIMER.',  # pylint: disable=line-too-long
+     )),
     ('mjs_isWarning',
      FunctionDecl(
          name='mjs_isWarning',

python/mujoco/specs.cc

@@ -55,6 +55,7 @@ using MjDouble3 = Eigen::Map<Eigen::Vector3d>;
 using MjDouble4 = Eigen::Map<Eigen::Vector4d>;
 using MjDouble5 = Eigen::Map<Eigen::Matrix<double, 5, 1>>;
 using MjDouble6 = Eigen::Map<Eigen::Matrix<double, 6, 1>>;
+using MjDouble9 = Eigen::Map<Eigen::Matrix<double, 9, 1>>;
 using MjDouble10 = Eigen::Map<Eigen::Matrix<double, 10, 1>>;
 using MjDouble11 = Eigen::Map<Eigen::Matrix<double, 11, 1>>;
 using MjDoubleVec = Eigen::Map<Eigen::VectorXd>;
@@ -69,6 +70,7 @@ using MjDoubleRef3 = Eigen::Ref<const Eigen::Vector3d>;
 using MjDoubleRef4 = Eigen::Ref<const Eigen::Vector4d>;
 using MjDoubleRef5 = Eigen::Ref<const Eigen::Matrix<double, 5, 1>>;
 using MjDoubleRef6 = Eigen::Ref<const Eigen::Matrix<double, 6, 1>>;
+using MjDoubleRef9 = Eigen::Ref<const Eigen::Matrix<double, 9, 1>>;
 using MjDoubleRef10 = Eigen::Ref<const Eigen::Matrix<double, 10, 1>>;
 using MjDoubleRef11 = Eigen::Ref<const Eigen::Matrix<double, 11, 1>>;
 using MjDoubleRefVec = Eigen::Ref<const Eigen::VectorXd>;
@@ -461,6 +463,12 @@ PYBIND11_MODULE(_specs, m) {
   mjSpec.def_property_readonly("_address", [](const MjSpec& self) {
     return reinterpret_cast<uintptr_t>(self.ptr);
   });
+  mjSpec.def_property_readonly(
+      "timer",
+      [](MjSpec& self) -> MjDouble9 {
+        return MjDouble9(const_cast<double*>(mjs_getTimer(self.ptr)));
+      },
+      py::return_value_policy::reference_internal);
   mjSpec.def_property(
       "copy_during_attach",
       [](MjSpec& self) {

python/mujoco/specs_test.py

@@ -47,6 +47,24 @@ class SpecsTest(absltest.TestCase):
     self.assertIsInstance(spec.worldbody, mujoco.MjsBody)
     self.assertIsInstance(spec.worldbody, typing.get_args(mujoco.MjStruct))
 
+  def test_timer(self):
+    xml = """
+    <mujoco>
+      <asset>
+        <texture name="grid" type="2d" builtin="checker" width="300" height="300" rgb1=".1 .2 .3" rgb2=".2 .3 .4"/>
+        <material name="grid" texture="grid"/>
+      </asset>
+      <worldbody>
+        <geom type="plane" size="1 1 1" material="grid"/>
+      </worldbody>
+    </mujoco>
+    """
+    spec = mujoco.MjSpec.from_string(xml)
+    model = spec.compile()
+    self.assertGreater(spec.timer[mujoco.mjtCTimer.mjCTIMER_TOTAL], 0)
+    self.assertGreater(spec.timer[mujoco.mjtCTimer.mjCTIMER_ASSETS], 0)
+    self.assertGreater(spec.timer[mujoco.mjtCTimer.mjCTIMER_TEXTURE], 0)
+
   def test_basic(self):
     # Create a spec.
     spec = mujoco.MjSpec()