[compile] Stop unconditionally patching constrain_to_fx_strides (#36152)

Signed-off-by: Richard Zou <zou3519@gmail.com>

vllm/compilation/compiler_interface.py

@@ -225,6 +225,48 @@ def _patch_standalone_compile_atomic_save() -> None:
     logger.debug("Patched %s.save for atomic writes (torch < 2.10)", cls.__name__)
 
 
+def _patch_constrain_to_fx_strides() -> contextlib.AbstractContextManager:
+    """Context manager that patches inductor's ``constrain_to_fx_strides``
+    to handle opaque (non-tensor) arguments.
+
+    The original calls ``.stride()`` on every FX arg's meta value, which
+    crashes on ``FakeScriptObject`` (the compile-time proxy for hoisted
+    opaque types).  The patched version skips args whose meta value is
+    not a ``torch.Tensor``.
+
+    Returns ``nullcontext`` on torch < 2.11.
+    Upstream issue: https://github.com/pytorch/pytorch/issues/175973
+    """
+    if not is_torch_equal_or_newer("2.11.0.dev"):
+        return contextlib.nullcontext()
+
+    import torch._inductor.ir as _ir
+    import torch._inductor.lowering as _lowering
+    from torch._inductor.virtualized import V as _V
+
+    def _patched(fx_node, *args, **kwargs):
+        def apply_constraint(arg, fx_arg):
+            if isinstance(arg, _ir.IRNode):
+                meta_val = fx_arg.meta.get("val")
+                if isinstance(meta_val, torch.Tensor):
+                    stride_order = _ir.get_stride_order(
+                        meta_val.stride(), _V.graph.sizevars.shape_env
+                    )
+                    return _ir.ExternKernel.require_stride_order(arg, stride_order)
+                return arg
+            if isinstance(arg, dict):
+                return {key: apply_constraint(arg[key], fx_arg[key]) for key in arg}
+            return arg
+
+        args = tuple(
+            apply_constraint(arg, fx_arg) for arg, fx_arg in zip(args, fx_node.args)
+        )
+        kwargs = {k: apply_constraint(v, fx_node.kwargs[k]) for k, v in kwargs.items()}
+        return args, kwargs
+
+    return patch.object(_lowering, "constrain_to_fx_strides", _patched)
+
+
 class InductorStandaloneAdaptor(CompilerInterface):
     """
     The adaptor for the Inductor compiler.
@@ -312,7 +354,7 @@ class InductorStandaloneAdaptor(CompilerInterface):
                 "torch._inductor.compile_fx._recursive_pre_grad_passes",
                 lambda gm, _: gm,
             )
-        with ctx:
+        with ctx, _patch_constrain_to_fx_strides():
             compiled_graph = standalone_compile(graph, example_inputs, **compile_kwargs)
 
         if use_aot:
@@ -555,6 +597,7 @@ class InductorAdaptor(CompilerInterface):
             stack.enter_context(
                 torch._functorch.config.patch(enable_remote_autograd_cache=False)
             )
+            stack.enter_context(_patch_constrain_to_fx_strides())
 
             compiled_graph = compile_fx(
                 graph,