AOTInductor dynamic shape (#109012)
Summary: This PR adds dynamic-shape support for AOTInductor
* On the runtime/interface side, we added two structs, StaticDimInfo
and DynamicDimInfo, to hold values for static and dynamic dimensions,
respectively. Dynamic dimensions are tracked by an unordered map field
defined in AOTInductorModelBase. At inference time, the inference run
method will assign the current real dimensional value to each dynamic
dimension before executing any kernel.
* On the CUDA wrapper codegen side, we generate dynamic symbols
appropriately for shape computations. We simulate kernel launch grids
in the C++ land by re-using the grid functions from the Python world.
The returned grid configs, which may contain symbolic expressions,
are printed out in their C++ forms via the CppPrinter. Note that
when dynamic shapes are involved, we have to compute grid configs
for each kernel at runtime in the same way as we do for launching
the corresponding Triton kernel. Otherwise, we may end up with
memory-access failures or mis-computations caused by invalid indices
for fetching or storing data in device memory.
Differential Revision: D49100472
Pull Request resolved: https://github.com/pytorch/pytorch/pull/109012
Approved by: https://github.com/khabinov, https://github.com/desertfire, https://github.com/hl475
