Push anonymous namespace into codegen, not template (#49498)

ezyang · facebook-github-bot · commit 68a6e4637903 · 2021-01-06T08:44:49.000-08:00
Summary: Pull Request resolved: #49498 In the near future, I want to code generate some functions that are visible externally to this compilation unit. I cannot easily do this if all the codegen code is wrapped in a global anonymous namespace, so push the namespace in. Registration has to stay in an anonymous namespace to avoid name conflicts. This could also have been solved by making the wrapper functions have more unique names but I didn't do this in the end. Signed-off-by: Edward Z. Yang <ezyang@fb.com> Test Plan: Imported from OSS Reviewed By: albanD, smessmer Differential Revision: D25616104 Pulled By: ezyang fbshipit-source-id: 323c0dda05a081502aab702f359a08dfac8c41a4
diff --git a/aten/src/ATen/templates/RegisterDispatchKey.cpp b/aten/src/ATen/templates/RegisterDispatchKey.cpp
@@ -37,10 +37,13 @@
 
 namespace at {
 
-namespace {
-
 ${dispatch_definitions}
 
+// NB: TORCH_LIBRARY_IMPL must be in an anonymous namespace to avoid
+// ambiguity with conflicting identifiers that may have been defined in
+// at namespace already.
+namespace {
+
 TORCH_LIBRARY_IMPL(aten, ${DispatchKey}, m) {
   ${dispatch_registrations}
 }
diff --git a/tools/codegen/gen.py b/tools/codegen/gen.py
@@ -435,6 +435,8 @@ def gen_one(f: NativeFunction) -> Optional[str]:
                 # For an overview of what this template code looks like, see
                 # https://github.com/pytorch/rfcs/pull/9
                 return f"""\
+namespace {{
+
 {self.gen_structured_class(
     f, k,
     class_name=class_name,
@@ -448,6 +450,8 @@ def gen_one(f: NativeFunction) -> Optional[str]:
     {impl_call}
     return {ret_expr};
 }}
+
+}} // anonymous namespace
 """
 
             elif self.target is Target.REGISTRATION:
@@ -540,9 +544,13 @@ def gen_unstructured(self, f: NativeFunction) -> Optional[str]:
 """
 
             return f"""\
+namespace {{
+
 {returns_type} {name}({args_str}) {{
 {cuda_guard}{return_kw}{impl_name}({args_exprs_str});
 }}
+
+}} // anonymous namespace
 """
 
         elif self.target is Target.REGISTRATION:
