Fix undefined behavior detected by clang-12 (#106354)
Compiler behavior when non-zero offset is added to a null pointer is undefined and is a bad habit.
- When `lapackEig` is called with to estimate a workspace size, do not add matrix size to the W pointer.
- When `unpack_pivots_cpu_kernel` with zero `dim_size` exit early.
- When `topk_impl_loop` is called with `k` is zero, exit right away as output tensors are empty anyway.
- Ignore adding non-zero storage-offset in `TensorImpl::data_ptr_impl_impl`, which can be the case if tensor is created as `torch.empty(3)[4:]`.
- In `s_addmm_out_sparse_dense_worker` do not call `axpy` over an empty vector.
- In `_sparse_binary_op_intersection_kernel_impl` do skip computing `ptr_indices_dim` when `sparse_dim` is empty.
- Exit `grid_sample` forward/backward kernels earlier if either `input` or `grid` are empty tensors.
Found by asan in clang-12
Before the change UBSan report looks as follows:
```
ASAN_SYMBOLIZER_PATH=/usr/lib/llvm-12/bin/llvm-symbolizer UBSAN_OPTIONS=print_stacktrace=1 LD_PRELOAD=/usr/lib/llvm-12/lib/clang/12.0.1/lib/linux/libclang_rt.asan-x86_64.so python test_fx_experimental.py -v -k test_normalize_operator_exhaustive_linalg_eig_cpu_float32
Test results will be stored in test-reports/python-unittest/test_fx_experimental
Running tests...
----------------------------------------------------------------------
test_normalize_operator_exhaustive_linalg_eig_cpu_float32 (__main__.TestNormalizeOperatorsCPU) ... /opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/overrides.py:111: UserWarning: 'has_cuda' is deprecated, please use 'torch.backends.cuda.is_built()'
torch.has_cuda,
/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/overrides.py:112: UserWarning: 'has_cudnn' is deprecated, please use 'torch.backends.cudnn.is_available()'
torch.has_cudnn,
/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/overrides.py:118: UserWarning: 'has_mps' is deprecated, please use 'torch.backends.mps.is_built()'
torch.has_mps,
/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/overrides.py:119: UserWarning: 'has_mkldnn' is deprecated, please use 'torch.backends.mkldnn.is_available()'
torch.has_mkldnn,
/var/lib/jenkins/workspace/aten/src/ATen/native/BatchLinearAlgebra.cpp:937:17: runtime error: applying non-zero offset 20 to null pointer
#0 0x7f2025794888 in void at::native::lapackEig<float, float>(char, char, int, float*, int, float*, float*, int, float*, int, float*, int, float*, int*) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0x9945888)
#1 0x7f20257da256 in void at::native::(anonymous namespace)::apply_linalg_eig<float>(at::Tensor&, at::Tensor&, at::Tensor&, at::Tensor&, bool) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0x998b256)
#2 0x7f20257d902d in at::native::(anonymous namespace)::linalg_eig_kernel(at::Tensor&, at::Tensor&, at::Tensor&, at::Tensor const&, bool) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0x998a02d)
#3 0x7f20257b5b3d in at::native::linalg_eig_out_info(at::Tensor const&, at::Tensor&, at::Tensor&, at::Tensor&, bool) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0x9966b3d)
#4 0x7f20257b4770 in at::native::linalg_eig_out(at::Tensor const&, at::Tensor&, at::Tensor&) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0x9965770)
#5 0x7f20280710e6 in c10::impl::wrap_kernel_functor_unboxed_<c10::impl::detail::WrapFunctionIntoFunctor_<c10::CompileTimeFunctionPointer<std::tuple<at::Tensor&, at::Tensor&> (at::Tensor const&, at::Tensor&, at::Tensor&), &(at::(anonymous namespace)::(anonymous namespace)::wrapper_CPU_out_linalg_eig_out(at::Tensor const&, at::Tensor&, at::Tensor&))>, std::tuple<at::Tensor&, at::Tensor&>, c10::guts::typelist::typelist<at::Tensor const&, at::Tensor&, at::Tensor&> >, std::tuple<at::Tensor&, at::Tensor&> (at::Tensor const&, at::Tensor&, at::Tensor&)>::call(c10::OperatorKernel*, c10::DispatchKeySet, at::Tensor const&, at::Tensor&, at::Tensor&) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0xc2220e6)
#6 0x7f202727a045 in at::_ops::linalg_eig_out::call(at::Tensor const&, at::Tensor&, at::Tensor&) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0xb42b045)
#7 0x7f20257b7e29 in at::native::linalg_eig(at::Tensor const&) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0x9968e29)
#8 0x7f2028070bf0 in c10::impl::wrap_kernel_functor_unboxed_<c10::impl::detail::WrapFunctionIntoFunctor_<c10::CompileTimeFunctionPointer<std::tuple<at::Tensor, at::Tensor> (at::Tensor const&), &(at::(anonymous namespace)::(anonymous namespace)::wrapper_CPU__linalg_eig(at::Tensor const&))>, std::tuple<at::Tensor, at::Tensor>, c10::guts::typelist::typelist<at::Tensor const&> >, std::tuple<at::Tensor, at::Tensor> (at::Tensor const&)>::call(c10::OperatorKernel*, c10::DispatchKeySet, at::Tensor const&) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0xc221bf0)
#9 0x7f2026b1f787 in std::tuple<at::Tensor, at::Tensor> c10::Dispatcher::redispatch<std::tuple<at::Tensor, at::Tensor>, at::Tensor const&>(c10::TypedOperatorHandle<std::tuple<at::Tensor, at::Tensor> (at::Tensor const&)> const&, c10::DispatchKeySet, at::Tensor const&) const (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0xacd0787)
#10 0x7f20273230a7 in at::_ops::linalg_eig::redispatch(c10::DispatchKeySet, at::Tensor const&) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0xb4d40a7)
#11 0x7f202c3cc32d in torch::autograd::VariableType::(anonymous namespace)::linalg_eig(c10::DispatchKeySet, at::Tensor const&) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0x1057d32d)
#12 0x7f202c3cba96 in c10::impl::wrap_kernel_functor_unboxed_<c10::impl::detail::WrapFunctionIntoFunctor_<c10::CompileTimeFunctionPointer<std::tuple<at::Tensor, at::Tensor> (c10::DispatchKeySet, at::Tensor const&), &(torch::autograd::VariableType::(anonymous namespace)::linalg_eig(c10::DispatchKeySet, at::Tensor const&))>, std::tuple<at::Tensor, at::Tensor>, c10::guts::typelist::typelist<c10::DispatchKeySet, at::Tensor const&> >, std::tuple<at::Tensor, at::Tensor> (c10::DispatchKeySet, at::Tensor const&)>::call(c10::OperatorKernel*, c10::DispatchKeySet, at::Tensor const&) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0x1057ca96)
#13 0x7f20272798e0 in at::_ops::linalg_eig::call(at::Tensor const&) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_cpu.so+0xb42a8e0)
#14 0x7f2043d97ae3 in torch::autograd::THPVariable_linalg_eig(_object*, _object*, _object*) (/opt/conda/envs/py_3.9/lib/python3.9/site-packages/torch/lib/libtorch_python.so+0x23feae3)
#15 0x5072d6 in cfunction_call /usr/local/src/conda/python-3.9.17/Objects/methodobject.c:543:19
...
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /var/lib/jenkins/workspace/aten/src/ATen/native/BatchLinearAlgebra.cpp:937:17 in
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106354
Approved by: https://github.com/huydhn, https://github.com/lezcano