Add a namespace for ATen mode (#9894)

Summary:
Pull Request resolved: #9894

## Context

As titled. This is an effort trying to solve a big pain point for ATen mode users: duplicate symbols and duplicate operators.

A typical duplicate symbol issue looks like:

```
ld.lld: error: duplicate symbol: executorch::runtime::Method::get_num_external_constants()
>>> defined at __stripped__/method.cpp.pic.stripped.o:(executorch::runtime::Method::get_num_external_constants()) in archive buck-out/v2/gen/fbcode/712c6d0a4cb497c7/executorch/runtime/executor/__program_no_prim_ops_aten__/libprogram_no_prim_ops_aten.stripped.pic.a
>>> defined at __stripped__/method.cpp.pic.stripped.o:(.text._ZN10executorch7runtime6Method26get_num_external_constantsEv+0x0) in archive buck-out/v2/gen/fbcode/712c6d0a4cb497c7/executorch/runtime/executor/__program_no_prim_ops__/libprogram_no_prim_ops.stripped.pic.a
```
[User post](https://fb.workplace.com/groups/pytorch.edge.users/permalink/1727735561430063/)

This is caused by user depending on both `program_no_prim_ops` and `program_no_prim_ops_aten`.

The issue happens because both libraries define symbols like: `executorch::runtime::Method` and they transitively depend on different definitions of `Tensor` and other types, see `exec_aten.h`.

The other common issue is re-registering operators:

```
buck2 test  //arvr/libraries/wristband/tsn/transformers:TorchstreamTransformer  -- --print-passing-details
File changed: fbsource//xplat/executorch/build/fb/clients.bzl
File changed: fbsource//xplat/executorch
File changed: fbcode//executorch/build/fb/clients.bzl
16 additional file change events
⚠ Listing failed: fbsource//arvr/libraries/wristband/tsn/transformers:TorchstreamTransformerTestFbcode
Failed to list tests. Expected exit code 0 but received: ExitStatus(unix_wait_status(134))
STDOUT:
STDERR:E 00:00:00.000543 executorch:operator_registry.cpp:86] Re-registering aten::sym_size.int, from /data/sandcastle/boxes/fbsource/buck-out/v2/gen/fbsource/cfdc20bd56300721/arvr/libraries/wristband/tsn/transformers/__TorchstreamTransformerTestFbcode__/./__TorchstreamTransformerTestFbcode__shared_libs_symlink_tre$
E 00:00:00.000572 executorch:operator_registry.cpp:87] key: (null), is_fallback: true
F 00:00:00.000576 executorch:operator_registry.cpp:111] In function register_kernels(), assert failed (false): Kernel registration failed with error 18, see error log for details.
```
[User post](https://fb.workplace.com/groups/pytorch.edge.users/permalink/1691696305033989/)
[User post 2](https://fb.workplace.com/groups/pytorch.edge.users/permalink/1510414646495490/)

This is worse than duplicate symbols because it's a runtime error. This happens because a user depends on a kernel library built with ATen tensors and a kernel library built with ET tensor at the same time. For example, if a C++ binary depends on `//executorch/kernels/prim_ops:prim_ops_registry` and `//executorch/kernels/prim_ops:prim_ops_registry_aten` then this will happen.

## My proposal

Add a new namespace to the symbols in ATen mode.

`executorch::runtime::Method` --> `executorch::runtime::aten::Method`

This way a C++ binary is allowed to depend on an ET library with ATen mode enabled and an ET library with ATen mode disabled.

This is not BC breaking for OSS users, since ATen mode was never exposed.

Differential Revision: D72440313

Author: larryliu0820

codegen/templates/RegisterCodegenUnboxedKernels.cpp

@@ -22,8 +22,8 @@
 // JIT op registry instead of c10 dispatcher. JIT op registry only takes boxed
 // kernels, so we are calling unboxing functions in UnboxingFunctions.h to cast
 // arguments into C++ types (instead of IValue) and delegate to unboxed kernels.
-using KernelSpan =
-    ::executorch::runtime::Span<const ::executorch::runtime::Kernel>;
+using KernelSpan = ::executorch::runtime::Span<
+    const ::executorch::ET_RUNTIME_NAMESPACE::Kernel>;
 namespace torch {
 namespace executor {
 namespace function {

extension/flat_tensor/flat_tensor_data_map.h

@@ -32,7 +32,8 @@ namespace extension {
 /**
  * A NamedDataMap implementation for FlatTensor-serialized data.
  */
-class FlatTensorDataMap final : public executorch::runtime::NamedDataMap {
+class FlatTensorDataMap final
+    : public executorch::ET_RUNTIME_NAMESPACE::NamedDataMap {
  public:
   /**
    * Creates a new DataMap that wraps FlatTensor data.

extension/flat_tensor/targets.bzl

@@ -1,24 +1,26 @@
 load("@fbsource//xplat/executorch/build:runtime_wrapper.bzl", "runtime")
 
 def define_common_targets():
-    runtime.cxx_library(
-        name = "flat_tensor_data_map",
-        srcs = [
-            "flat_tensor_data_map.cpp",
-        ],
-        exported_headers = ["flat_tensor_data_map.h"],
-        deps = [
-            "//executorch/runtime/core:core",
-            "//executorch/runtime/core:evalue",
-            "//executorch/runtime/core:named_data_map",
-            "//executorch/runtime/core/exec_aten:lib",
-            "//executorch/runtime/core/exec_aten/util:tensor_util",
-        ],
-        exported_deps = [
-            "//executorch/extension/flat_tensor/serialize:flat_tensor_header",
-            "//executorch/extension/flat_tensor/serialize:generated_headers",
-        ],
-        visibility = [
-            "//executorch/...",
-        ],
-    )
+    for aten_mode in [True, False]:
+        aten_suffix = "_aten" if aten_mode else ""
+        runtime.cxx_library(
+            name = "flat_tensor_data_map" + aten_suffix,
+            srcs = [
+                "flat_tensor_data_map.cpp",
+            ],
+            exported_headers = ["flat_tensor_data_map.h"],
+            deps = [
+                "//executorch/runtime/core:core",
+                "//executorch/runtime/core:evalue",
+                "//executorch/runtime/core:named_data_map" + aten_suffix,
+                "//executorch/runtime/core/exec_aten:lib" + aten_suffix,
+                "//executorch/runtime/core/exec_aten/util:tensor_util",
+            ],
+            exported_deps = [
+                "//executorch/extension/flat_tensor/serialize:flat_tensor_header",
+                "//executorch/extension/flat_tensor/serialize:generated_headers",
+            ],
+            visibility = [
+                "//executorch/...",
+            ],
+        )

extension/module/module.cpp

@@ -37,6 +37,9 @@
 namespace executorch {
 namespace extension {
 
+using ET_RUNTIME_NAMESPACE::MethodMeta;
+using ET_RUNTIME_NAMESPACE::Program;
+
 namespace {
 runtime::Result<std::unique_ptr<runtime::DataLoader>> load_file(
     const std::string& file_path,
@@ -113,7 +116,7 @@ Module::Module(
 }
 
 Module::Module(
-    std::shared_ptr<runtime::Program> program,
+    std::shared_ptr<Program> program,
     std::unique_ptr<runtime::MemoryAllocator> memory_allocator,
     std::unique_ptr<runtime::MemoryAllocator> temp_allocator,
     std::unique_ptr<runtime::EventTracer> event_tracer,
@@ -131,7 +134,7 @@ Module::Module(
   runtime::runtime_init();
 }
 
-runtime::Error Module::load(const runtime::Program::Verification verification) {
+runtime::Error Module::load(const Program::Verification verification) {
   if (!is_loaded()) {
     // Load the program
     if (!data_loader_) {
@@ -156,10 +159,10 @@ runtime::Error Module::load(const runtime::Program::Verification verification) {
     }
     // else: either the map itself was provided or we have no data map, either
     // way no work to do.
-    auto program = ET_UNWRAP_UNIQUE(
-        runtime::Program::load(data_loader_.get(), verification));
-    program_ = std::shared_ptr<runtime::Program>(
-        program.release(), [](runtime::Program* pointer) { delete pointer; });
+    auto program =
+        ET_UNWRAP_UNIQUE(Program::load(data_loader_.get(), verification));
+    program_ = std::shared_ptr<Program>(
+        program.release(), [](Program* pointer) { delete pointer; });
   }
   return runtime::Error::Ok;
 }
@@ -224,7 +227,7 @@ runtime::Error Module::load_method(
   return runtime::Error::Ok;
 }
 
-runtime::Result<runtime::MethodMeta> Module::method_meta(
+runtime::Result<MethodMeta> Module::method_meta(
     const std::string& method_name) {
   ET_CHECK_OK_OR_RETURN_ERROR(load_method(method_name));
   return methods_.at(method_name).method->method_meta();

extension/module/module.h

@@ -19,6 +19,11 @@
 namespace executorch {
 namespace extension {
 
+using ET_RUNTIME_NAMESPACE::Method;
+using ET_RUNTIME_NAMESPACE::MethodMeta;
+using ET_RUNTIME_NAMESPACE::NamedDataMap;
+using ET_RUNTIME_NAMESPACE::Program;
+
 /**
  * A facade class for loading programs and executing methods within them.
  */
@@ -95,7 +100,7 @@ class Module {
    * @param[in] data_map_loader A DataLoader used for loading external weights.
    */
   explicit Module(
-      std::shared_ptr<runtime::Program> program,
+      std::shared_ptr<Program> program,
       std::unique_ptr<runtime::MemoryAllocator> memory_allocator = nullptr,
       std::unique_ptr<runtime::MemoryAllocator> temp_allocator = nullptr,
       std::unique_ptr<runtime::EventTracer> event_tracer = nullptr,
@@ -116,8 +121,8 @@ class Module {
    */
   ET_NODISCARD
   runtime::Error load(
-      const runtime::Program::Verification verification =
-          runtime::Program::Verification::Minimal);
+      const Program::Verification verification =
+          Program::Verification::Minimal);
 
   /**
    * Checks if the program is loaded.
@@ -134,7 +139,7 @@ class Module {
    *
    * @returns Shared pointer to the program or nullptr if it's not yet loaded.
    */
-  inline std::shared_ptr<runtime::Program> program() const {
+  inline std::shared_ptr<Program> program() const {
     return program_;
   }
 
@@ -224,8 +229,7 @@ class Module {
    * @returns A method metadata, or an error if the program or method failed to
    * load.
    */
-  runtime::Result<runtime::MethodMeta> method_meta(
-      const std::string& method_name);
+  runtime::Result<MethodMeta> method_meta(const std::string& method_name);
 
   /**
    * Execute a specific method with the given input values and retrieve the
@@ -473,20 +477,20 @@ class Module {
     std::vector<runtime::Span<uint8_t>> planned_spans;
     std::unique_ptr<runtime::HierarchicalAllocator> planned_memory;
     std::unique_ptr<runtime::MemoryManager> memory_manager;
-    std::unique_ptr<runtime::Method> method;
+    std::unique_ptr<Method> method;
     std::vector<runtime::EValue> inputs;
   };
 
   std::string file_path_;
   std::string data_map_path_;
   LoadMode load_mode_{LoadMode::MmapUseMlock};
-  std::shared_ptr<runtime::Program> program_;
+  std::shared_ptr<Program> program_;
   std::unique_ptr<runtime::DataLoader> data_loader_;
   std::unique_ptr<runtime::MemoryAllocator> memory_allocator_;
   std::unique_ptr<runtime::MemoryAllocator> temp_allocator_;
   std::unique_ptr<runtime::EventTracer> event_tracer_;
   std::unique_ptr<runtime::DataLoader> data_map_loader_;
-  std::unique_ptr<runtime::NamedDataMap> data_map_;
+  std::unique_ptr<NamedDataMap> data_map_;
 
  protected:
   std::unordered_map<std::string, MethodHolder> methods_;

extension/module/targets.bzl

@@ -25,7 +25,7 @@ def define_common_targets():
                 "//executorch/extension/memory_allocator:malloc_memory_allocator",
                 "//executorch/extension/data_loader:file_data_loader",
                 "//executorch/extension/data_loader:mmap_data_loader",
-                "//executorch/extension/flat_tensor:flat_tensor_data_map",
+                "//executorch/extension/flat_tensor:flat_tensor_data_map" + aten_suffix,
             ],
             exported_deps = [
                 "//executorch/runtime/executor:program" + aten_suffix,

kernels/prim_ops/register_prim_ops.cpp

@@ -381,14 +381,13 @@ static Kernel prim_ops[] = {
 
 };
 
-executorch::runtime::Span<const executorch::runtime::Kernel> kernel_span(
-    prim_ops,
-    prim_ops + sizeof(prim_ops) / sizeof(Kernel));
+executorch::runtime::Span<const executorch::ET_RUNTIME_NAMESPACE::Kernel>
+    kernel_span(prim_ops, prim_ops + sizeof(prim_ops) / sizeof(Kernel));
 
 // Return value not used. Keep the static variable assignment to register
 // operators in static initialization time.
 auto success_with_kernel_reg =
-    executorch::runtime::register_kernels(kernel_span);
+    executorch::ET_RUNTIME_NAMESPACE::register_kernels(kernel_span);
 
 } // namespace
 } // namespace function

runtime/backend/backend_execution_context.h

@@ -12,7 +12,7 @@
 #include <executorch/runtime/core/memory_allocator.h>
 
 namespace executorch {
-namespace runtime {
+namespace ET_RUNTIME_NAMESPACE {
 
 /**
  * BackendExecutionContext will be used to inject run time context.
@@ -68,13 +68,13 @@ class BackendExecutionContext final {
   const char* method_name_ = nullptr;
 };
 
-} // namespace runtime
+} // namespace ET_RUNTIME_NAMESPACE
 } // namespace executorch
 
 namespace torch {
 namespace executor {
 // TODO(T197294990): Remove these deprecated aliases once all users have moved
 // to the new `::executorch` namespaces.
-using ::executorch::runtime::BackendExecutionContext;
+using ::executorch::ET_RUNTIME_NAMESPACE::BackendExecutionContext;
 } // namespace executor
 } // namespace torch

runtime/backend/backend_init_context.h

@@ -7,12 +7,12 @@
  */
 
 #pragma once
+#include <executorch/runtime/core/event_tracer.h>
 #include <executorch/runtime/core/memory_allocator.h>
 #include <executorch/runtime/core/named_data_map.h>
 
 namespace executorch {
-namespace runtime {
-
+namespace ET_RUNTIME_NAMESPACE {
 /**
  * BackendInitContext will be used to inject runtime info for to initialize
  * delegate.
@@ -70,13 +70,13 @@ class BackendInitContext final {
   const NamedDataMap* named_data_map_ = nullptr;
 };
 
-} // namespace runtime
+} // namespace ET_RUNTIME_NAMESPACE
 } // namespace executorch
 
 namespace torch {
 namespace executor {
 // TODO(T197294990): Remove these deprecated aliases once all users have moved
 // to the new `::executorch` namespaces.
-using ::executorch::runtime::BackendInitContext;
+using ::executorch::ET_RUNTIME_NAMESPACE::BackendInitContext;
 } // namespace executor
 } // namespace torch

runtime/backend/interface.cpp

@@ -9,7 +9,7 @@
 #include <executorch/runtime/backend/interface.h>
 
 namespace executorch {
-namespace runtime {
+namespace ET_RUNTIME_NAMESPACE {
 
 // Pure-virtual dtors still need an implementation.
 BackendInterface::~BackendInterface() {}
@@ -66,5 +66,5 @@ Result<const char*> get_backend_name(size_t index) {
   return registered_backends[index].name;
 }
 
-} // namespace runtime
+} // namespace ET_RUNTIME_NAMESPACE
 } // namespace executorch

runtime/backend/interface.h

@@ -22,7 +22,7 @@
 #include <executorch/runtime/platform/compiler.h>
 
 namespace executorch {
-namespace runtime {
+namespace ET_RUNTIME_NAMESPACE {
 
 struct SizedBuffer {
   void* buffer;
@@ -150,19 +150,19 @@ size_t get_num_registered_backends();
  */
 Result<const char*> get_backend_name(size_t index);
 
-} // namespace runtime
+} // namespace ET_RUNTIME_NAMESPACE
 } // namespace executorch
 
 namespace torch {
 namespace executor {
 // TODO(T197294990): Remove these deprecated aliases once all users have moved
 // to the new `::executorch` namespaces.
-using ::executorch::runtime::Backend;
-using ::executorch::runtime::CompileSpec;
-using ::executorch::runtime::DelegateHandle;
-using ::executorch::runtime::get_backend_class;
-using ::executorch::runtime::register_backend;
-using ::executorch::runtime::SizedBuffer;
-using PyTorchBackendInterface = ::executorch::runtime::BackendInterface;
+using ::executorch::ET_RUNTIME_NAMESPACE::Backend;
+using ::executorch::ET_RUNTIME_NAMESPACE::CompileSpec;
+using ::executorch::ET_RUNTIME_NAMESPACE::DelegateHandle;
+using ::executorch::ET_RUNTIME_NAMESPACE::get_backend_class;
+using ::executorch::ET_RUNTIME_NAMESPACE::register_backend;
+using ::executorch::ET_RUNTIME_NAMESPACE::SizedBuffer;
+using PyTorchBackendInterface = ::executorch::ET_RUNTIME_NAMESPACE::BackendInterface;
 } // namespace executor
 } // namespace torch

runtime/core/event_tracer_hooks.h

@@ -30,7 +30,7 @@
  */
 
 namespace executorch {
-namespace runtime {
+namespace ET_RUNTIME_NAMESPACE {
 namespace internal {
 
 /**
@@ -305,26 +305,35 @@ inline void event_tracer_set_bundled_input_index(
 }
 
 } // namespace internal
-} // namespace runtime
+} // namespace ET_RUNTIME_NAMESPACE
 } // namespace executorch
 
 namespace torch {
 namespace executor {
 namespace internal {
 // TODO(T197294990): Remove these deprecated aliases once all users have moved
 // to the new `::executorch` namespaces.
-using ::executorch::runtime::internal::event_tracer_begin_profiling_event;
-using ::executorch::runtime::internal::event_tracer_create_event_block;
-using ::executorch::runtime::internal::event_tracer_end_profiling_event;
-using ::executorch::runtime::internal::event_tracer_log_evalue;
-using ::executorch::runtime::internal::event_tracer_log_evalue_output;
-using ::executorch::runtime::internal::event_tracer_set_bundled_input_index;
-using ::executorch::runtime::internal::event_tracer_track_allocation;
-using ::executorch::runtime::internal::event_tracer_track_allocator;
-using ::executorch::runtime::internal::EventTracerProfileInstructionScope;
-using ::executorch::runtime::internal::EventTracerProfileMethodScope;
-using ::executorch::runtime::internal::EventTracerProfileOpScope;
-using ::executorch::runtime::internal::EventTracerProfileScope;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::
+    event_tracer_begin_profiling_event;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::
+    event_tracer_create_event_block;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::
+    event_tracer_end_profiling_event;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::event_tracer_log_evalue;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::
+    event_tracer_log_evalue_output;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::
+    event_tracer_set_bundled_input_index;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::
+    event_tracer_track_allocation;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::
+    event_tracer_track_allocator;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::
+    EventTracerProfileInstructionScope;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::
+    EventTracerProfileMethodScope;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::EventTracerProfileOpScope;
+using ::executorch::ET_RUNTIME_NAMESPACE::internal::EventTracerProfileScope;
 
 } // namespace internal
 } // namespace executor