Fix error message for missing allocation for base_storage

[kaushikcfd]

Hi!

I have the following code snippet which would generate sound code in earlier versions, but does not anymore:

import loopy as lp
import numpy as np


t_unit = lp.make_kernel(
    "{[i, j1,j2]: 0<=i<n and 0<=j1,j2<5}",
    """
    for i
        for j1
            <> tmp1[j1] = x1[i, j1]
            out1[i, j1] = tmp1[j1]
        end
        ... lbarrier
        for j2
            <> tmp2[j2] = x2[i, j2]
            out2[i, j2] = tmp2[j2]
        end
    end
    """,
    [lp.GlobalArg("x1,x2,out1,out2",
                  shape=lp.auto,
                  dtype=np.float64),
     ...],
    seq_dependencies=True,
)

knl = t_unit.default_entrypoint
new_tvs = {name: tv.copy(base_storage="my_base",
                         address_space=lp.AddressSpace.LOCAL)
           for name, tv in knl.temporary_variables.items()}
knl = knl.copy(temporary_variables=new_tvs)
t_unit = t_unit.with_kernel(knl)
print(lp.generate_code_v2(t_unit).device_code())

This raises with the following exception:

  File "/home/kgk2/projects/firedrake_gpu/src/loopy/loopy/check.py", line 1315, in check_for_nested_base_storage
    raise ValueError("nothing known about storage array "
ValueError: nothing known about storage array 'my_base' serving as base_storage of 'tmp1'

[inducer]

You need to call allocate_temporaries_for_base_storage (or allocate it yourself). Implicit allocation had been deprecated a while.

[inducer]

But the error message is definitely unhelpful, we should fix that. I'll leave this issue open as a reminder to do that.

[kaushikcfd]

call allocate_temporaries_for_base_storage

Thanks, that was it!