cpp_wrapper: fix set_.source_Tensor lowering (#145654)

Adds a C-shim fallback for `set_.source_Tensor`, which is effectively required by `ir.SetSourceTensorKernel`. As a necessary prerequisite to use that IR node, updates `CppWrapperCpu` to handle in-place returns in C-shim ops (the arguments for those returns are silently dropped by `torchgen`).

Pull Request resolved: https://github.com/pytorch/pytorch/pull/145654
Approved by: https://github.com/desertfire
ghstack dependencies: #145095

.ci/pytorch/test.sh

@@ -415,6 +415,10 @@ test_inductor_cpp_wrapper_shard() {
   # Run certain inductor unit tests with cpp wrapper. In the end state, we
   # should be able to run all the inductor unit tests with cpp_wrapper.
   python test/run_test.py --include inductor/test_torchinductor --verbose
+  python test/run_test.py \
+    --include inductor/test_cpu_repro \
+    -k 'test_set_source_Tensor' \
+    --verbose
 
   # Run inductor benchmark tests with cpp wrapper.
   # Skip benchmark tests if it's in rerun-disabled-mode.

test/inductor/test_cpu_repro.py

@@ -714,12 +714,15 @@ class CPUReproTests(TestCase):
         model = M(H=32, W=32, num_channels=4, num_colors=2)
         fn_opt = torch.compile(model, backend="inductor")
         v = (torch.rand(10, 32, 32, 4) > 0.5).to(torch.float32)
-        inps = [
-            v.clone(),
-        ]
-        result, code = run_and_get_cpp_code(fn_opt, *inps)
-        self.assertTrue("aten.set_.source_Tensor" in code)
-        self.assertEqual(model(*inps), result)
+        inp = v.clone()
+        result, code = run_and_get_cpp_code(fn_opt, inp)
+        self.assertIn(
+            "aoti_torch_cpu_set__source_Tensor"
+            if config.cpp_wrapper
+            else "aten.set_.source_Tensor",
+            code,
+        )
+        self.assertEqual(model(inp), result)
 
     @torch._dynamo.config.patch(dynamic_shapes=True)
     @torch._dynamo.config.patch(assume_static_by_default=False)

torch/_inductor/codegen/cpp_wrapper_cpu.py

@@ -1042,16 +1042,23 @@ class CppWrapperCpu(PythonWrapperCodegen):
                 f"AOTI_TORCH_ERROR_CODE_CHECK({shim_fn}({', '.join(args)}));"
             )
 
-    def generate_c_shim_extern_kernel_alloc(self, extern_kernel, args):
+    def generate_c_shim_extern_kernel_alloc(
+        self, extern_kernel: ir.ExternKernelAlloc, args: list[str]
+    ) -> None:
         # registered output buffer name
         name = extern_kernel.name
         output_handle_name = f"{name}_handle"
-        self.writeline(f"AtenTensorHandle {output_handle_name};")
-        output_arg = f"&{output_handle_name}"
-        self.generate_c_shim_extern_kernel_call(
-            extern_kernel.get_kernel_name(), args + [output_arg]
+        is_inplace = (
+            isinstance(extern_kernel.op_overload, torch._ops.OpOverload)
+            and torch.Tag.inplace_view in extern_kernel.op_overload.tags
         )
-        self.writeline(f"RAIIAtenTensorHandle {name}({output_handle_name});")
+
+        if not is_inplace:
+            self.writeline(f"AtenTensorHandle {output_handle_name};")
+            args = [*args, f"&{output_handle_name}"]
+        self.generate_c_shim_extern_kernel_call(extern_kernel.get_kernel_name(), args)
+        if not is_inplace:
+            self.writeline(f"RAIIAtenTensorHandle {name}({output_handle_name});")
 
     def generate_extern_kernel_alloc(self, extern_kernel, args):
         if getattr(extern_kernel, "outputs", None):

torch/csrc/inductor/aoti_torch/generated/c_shim_cpu.h

@@ -127,6 +127,7 @@ AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cpu_scatter_reduce_two_out(AtenTenso
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cpu_searchsorted_Scalar(AtenTensorHandle sorted_sequence, double self, int32_t out_int32, int32_t right, const char** side, AtenTensorHandle* sorter, AtenTensorHandle* ret0);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cpu_searchsorted_Tensor(AtenTensorHandle sorted_sequence, AtenTensorHandle self, int32_t out_int32, int32_t right, const char** side, AtenTensorHandle* sorter, AtenTensorHandle* ret0);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cpu_segment_reduce(AtenTensorHandle data, const char* reduce, AtenTensorHandle* lengths, AtenTensorHandle* indices, AtenTensorHandle* offsets, int64_t axis, int32_t unsafe, double* initial, AtenTensorHandle* ret0);
+AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cpu_set__source_Tensor(AtenTensorHandle self, AtenTensorHandle source);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cpu_slice_Tensor(AtenTensorHandle self, int64_t dim, int64_t* start, int64_t* end, int64_t step, AtenTensorHandle* ret0);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cpu_soft_margin_loss_backward(AtenTensorHandle grad_output, AtenTensorHandle self, AtenTensorHandle target, int64_t reduction, AtenTensorHandle* ret0);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cpu_sort(AtenTensorHandle self, int64_t dim, int32_t descending, AtenTensorHandle* ret0, AtenTensorHandle* ret1);

torch/csrc/inductor/aoti_torch/generated/c_shim_cuda.h

@@ -134,6 +134,7 @@ AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cuda_scatter_reduce_two_out(AtenTens
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cuda_searchsorted_Scalar(AtenTensorHandle sorted_sequence, double self, int32_t out_int32, int32_t right, const char** side, AtenTensorHandle* sorter, AtenTensorHandle* ret0);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cuda_searchsorted_Tensor(AtenTensorHandle sorted_sequence, AtenTensorHandle self, int32_t out_int32, int32_t right, const char** side, AtenTensorHandle* sorter, AtenTensorHandle* ret0);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cuda_segment_reduce(AtenTensorHandle data, const char* reduce, AtenTensorHandle* lengths, AtenTensorHandle* indices, AtenTensorHandle* offsets, int64_t axis, int32_t unsafe, double* initial, AtenTensorHandle* ret0);
+AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cuda_set__source_Tensor(AtenTensorHandle self, AtenTensorHandle source);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cuda_slice_Tensor(AtenTensorHandle self, int64_t dim, int64_t* start, int64_t* end, int64_t step, AtenTensorHandle* ret0);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cuda_soft_margin_loss_backward(AtenTensorHandle grad_output, AtenTensorHandle self, AtenTensorHandle target, int64_t reduction, AtenTensorHandle* ret0);
 AOTI_TORCH_EXPORT AOTITorchError aoti_torch_cuda_sort(AtenTensorHandle self, int64_t dim, int32_t descending, AtenTensorHandle* ret0, AtenTensorHandle* ret1);

torchgen/aoti/fallback_ops.py

@@ -134,6 +134,7 @@ inductor_fallback_ops = {
     "aten.searchsorted.Tensor",
     "aten._segment_reduce_backward.default",
     "aten.segment_reduce.default",
+    "aten.set_.source_Tensor",
     "aten.slice.Tensor",
     "aten.soft_margin_loss_backward.default",
     "aten.sort.default",