Merge CompilationUnit from torch._C and torch.jit (pytorch#50614)

Summary:
This simplifies our handling and allows passing CompilationUnits from Python to C++ defined functions via PyBind easily.

Discussed on Slack with SplitInfinity

Pull Request resolved: pytorch#50614

Reviewed By: anjali411

Differential Revision: D25938005

Pulled By: SplitInfinity

fbshipit-source-id: 94aadf0c063ddfef7ca9ea17bfa998d8e7b367ad

Author: t-vi

test/jit/test_python_bindings.py

@@ -0,0 +1,37 @@
+import torch
+from torch.testing._internal.jit_utils import JitTestCase
+
+if __name__ == "__main__":
+    raise RuntimeError(
+        "This test file is not meant to be run directly, use:\n\n"
+        "\tpython test/test_jit.py TestPythonBindings\n\n"
+        "instead."
+    )
+
+
+class TestPythonBindings(JitTestCase):
+    def test_cu_get_functions(self):
+        @torch.jit.script
+        def test_get_python_cu_fn(x: torch.Tensor):
+            return 2 * x
+
+        cu = torch.jit._state._python_cu
+        self.assertTrue(
+            "test_get_python_cu_fn" in (str(fn.name) for fn in cu.get_functions())
+        )
+
+    def test_cu_create_function(self):
+        @torch.jit.script
+        def fn(x: torch.Tensor):
+            return 2 * x
+
+        cu = torch._C.CompilationUnit()
+        cu.create_function("test_fn", fn.graph)
+
+        inp = torch.randn(5)
+
+        self.assertEqual(inp * 2, cu.find_function("test_fn")(inp))
+        self.assertEqual(cu.find_function("doesnt_exist"), None)
+        self.assertEqual(inp * 2, cu.test_fn(inp))
+        with self.assertRaises(AttributeError):
+            cu.doesnt_exist(inp)

test/test_jit.py

@@ -23,6 +23,7 @@
 from jit.test_peephole import TestPeephole  # noqa: F401
 from jit.test_save_load import TestSaveLoad  # noqa: F401
 from jit.test_module_containers import TestModuleContainers  # noqa: F401
+from jit.test_python_bindings import TestPythonBindings  # noqa: F401
 from jit.test_python_ir import TestPythonIr  # noqa: F401
 from jit.test_functional_blocks import TestFunctionalBlocks  # noqa: F401
 from jit.test_remove_mutation import TestRemoveMutation  # noqa: F401

torch/_C/__init__.pyi.in

@@ -415,10 +415,13 @@ class ErrorReport:
     def call_stack() -> str: ...
 
 class CompilationUnit:
-    def __init__(self) -> None: ...
+    def __init__(self, lang: str=..., _frames_up: _int=...) -> None: ...
     def find_function(self, name: str) -> ScriptFunction: ...
-    def define(self, script: str, rcb: ResolutionCallback): ...
+    def __getattr__(self, name: str) -> ScriptFunction: ...
+    def define(self, script: str, rcb: ResolutionCallback=..., _frames_up: _int=...): ...
     def get_interface(self, name: str) -> InterfaceType: ...
+    def get_functions(self) -> List[ScriptFunction]: ...
+    def create_function(self, name: str, graph: Graph, shouldMangle: _bool=...) -> ScriptFunction: ...
 
 class ScriptModule:
     def setattr(self, name: str, value: Any): ...
@@ -429,6 +432,7 @@ class ScriptFunction:
     def __call__(self, *args, **kwargs) -> Tensor: ...
     def save(self, filename: str, _extra_files: Dict[str, bytes]) -> None: ...
     def save_to_buffer(self, _extra_files: Dict[str, bytes]) -> bytes: ...
+    @property
     def graph(self) -> Graph: ...
     def inlined_graph(self) -> Graph: ...
     def schema(self) -> FunctionSchema: ...

torch/csrc/jit/python/script_init.cpp

@@ -710,6 +710,22 @@ void extra_files_to_python(const ExtraFilesMap& m, const py::dict& pydict) {
   }
 }
 
+void pyCompilationUnitDefine(
+    CompilationUnit& cu,
+    const std::string& src,
+    const ResolutionCallback* rcb,
+    const uint32_t _frames_up) {
+  if (rcb && *rcb) {
+    cu.define(c10::nullopt, src, pythonResolver(*rcb), nullptr);
+  } else {
+    py::object py_default_rcb =
+        py::module::import("torch._jit_internal")
+            .attr("createResolutionCallbackFromFrame")(_frames_up);
+    auto default_rcb = py_default_rcb.cast<ResolutionCallback>();
+    cu.define(c10::nullopt, src, pythonResolver(default_rcb), nullptr);
+  }
+}
+
 void initJitScriptBindings(PyObject* module) {
   auto m = py::handle(module).cast<py::module>();
 
@@ -1114,21 +1130,72 @@ void initJitScriptBindings(PyObject* module) {
 
   py::class_<CompilationUnit, std::shared_ptr<CompilationUnit>>(
       m, "CompilationUnit")
-      .def(py::init<>())
+      .def(
+          py::init([](const std::string& lang, const uint32_t _frames_up) {
+            auto cu = std::make_shared<CompilationUnit>();
+            if (lang.size() > 0) {
+              pyCompilationUnitDefine(*cu, lang, nullptr, _frames_up);
+            }
+            return cu;
+          }),
+          py::arg("lang") = "",
+          py::arg("_frames_up") = 0)
+
       .def(
           "find_function",
           [](std::shared_ptr<CompilationUnit> self, const std::string& name) {
-            auto& fn = self->get_function(QualifiedName(name));
-            return StrongFunctionPtr(std::move(self), &fn);
+            auto fn = self->find_function(QualifiedName(name));
+            if (fn) {
+              return c10::optional<StrongFunctionPtr>(
+                  StrongFunctionPtr(std::move(self), fn));
+            } else {
+              return c10::optional<StrongFunctionPtr>(c10::nullopt);
+            }
+          })
+      .def(
+          "__getattr__",
+          [](std::shared_ptr<CompilationUnit> self, const std::string& name) {
+            auto fn = self->find_function(QualifiedName(name));
+            if (fn) {
+              return StrongFunctionPtr(std::move(self), fn);
+            } else {
+              throw AttributeError(
+                  "'CompilationUnit' has no attribute '%s'", name.c_str());
+            }
+          })
+      .def(
+          "get_functions",
+          [](const std::shared_ptr<CompilationUnit>& self) {
+            auto raw_functions = self->get_functions();
+            std::vector<StrongFunctionPtr> functions;
+            functions.reserve(raw_functions.size());
+            for (auto fn : raw_functions) {
+              if (fn) {
+                functions.emplace_back(self, fn);
+              }
+            }
+            return functions;
           })
       .def("set_optimized", &CompilationUnit::set_optimized)
       .def(
           "define",
-          [](CompilationUnit& cu,
-             const std::string& src,
-             const ResolutionCallback& rcb) {
-            cu.define(c10::nullopt, src, pythonResolver(rcb), nullptr);
-          })
+          pyCompilationUnitDefine,
+          py::arg("src"),
+          py::arg("rcb") = nullptr,
+          py::arg("_frames_up") = 0)
+      .def(
+          "create_function",
+          [](std::shared_ptr<CompilationUnit>& self,
+             const std::string& qualified_name,
+             std::shared_ptr<Graph> graph,
+             bool should_mangle) {
+            Function* fn = self->create_function(
+                qualified_name, std::move(graph), should_mangle);
+            return StrongFunctionPtr(std::move(self), fn);
+          },
+          py::arg("qualified_name"),
+          py::arg("graph"),
+          py::arg("should_mangle") = false)
       .def(
           "get_interface",
           [](const std::shared_ptr<CompilationUnit>& self,

torch/jit/_script.py

@@ -1095,24 +1095,8 @@ def _recursive_compile_class(obj, loc):
     rcb = _jit_internal.createResolutionCallbackForClassMethods(obj)
     _compile_and_register_class(obj, rcb, _qual_name)
 
-
-class CompilationUnit(object):
-    def __init__(self, lang=None, _frames_up=0):
-        self._c = torch._C.CompilationUnit()
-        if lang is not None:
-            self.define(lang, _frames_up=_frames_up + 1)
-
-    def define(self, lang, rcb=None, _frames_up=0):
-        if not rcb:
-            rcb = _jit_internal.createResolutionCallbackFromFrame(_frames_up + 1)
-        self._c.define(lang, rcb)
-
-    def __getattr__(self, attr):
-        r = self._c.find_function(attr)
-        if r is None:
-            raise AttributeError("'CompilationUnit' has no attribute '{}'".format(attr))
-        return r
-
+CompilationUnit = torch._C.CompilationUnit
+set_module(CompilationUnit, "torch.jit")
 
 def _unwrap_optional(x):
     assert x is not None, "Unwrapping null optional"