Timothy Arceri <t_arc...@yahoo.com.au> writes:
> On Sun, 2015-08-16 at 13:15 +0300, Francisco Jerez wrote:
>> Timothy Arceri <t_arc...@yahoo.com.au> writes:
>>
>> > On Sat, 2015-08-15 at 17:33 +0300, Francisco Jerez wrote:
>> > > Timothy Arceri <t_arc...@yahoo.com.au> writes:
>> > >
>> > > > On Wed, 2015-08-12 at 19:39 +1000, Timothy Arceri wrote:
>> > > > > Cc: Francisco Jerez <curroje...@riseup.net>
>> > > > > ---
>> > > > > This patch works for direct indexing of images, but I'm having some
>> > > > > trouble
>> > > > > getting indirect to work.
>> > > > >
>> > > > > For example for:
>> > > > > tests/spec/arb_arrays_of_arrays/execution/image_store/basic
>> > > > > -imageStore
>> > > > > -non-const-uniform-index.shader_test
>> > > > >
>> > > > > Which has and image writeonly uniform image2D tex[2][2]
>> > > > >
>> > > > > Indirect indexing will work for tex[0][0] and text[0][1] but not
>> > > > > for
>> > > > > tex[1][0] and tex[1][1] they seem to always end up refering to the
>> > > > > image in 0.
>> > > >
>> > > > Just to add some more to this, I'm pretty sure my code is generating
>> > > > the
>> > > > correct offsets. If I hardcode the img_offset offset to 72 to get the
>> > > > uniform
>> > > > value of tex[1][0] I get the value I expected, but if I set
>> > > > image.reladdr
>> > > > to a
>> > > > register that contains 72 I don't what I expect.
>> > > >
>> > > > If I change the array to be a single dimension e.g. tex[4] and I
>> > > > hardcode
>> > > > the
>> > > > offset as described above then it works as expected for both
>> > > > scenarios, it
>> > > > also works if I split the offset across img_offset and image.reladdr,
>> > > > there is
>> > > > something going on with image.reladdr for multi-dimensional arrays
>> > > > that I
>> > > > can'
>> > > > t quite put my finger on.
>> > > >
>> > > > Any hints appreciated.
>> > > >
>> > > Odd, can you attach an assembly dump?
>> > >
>> > > Thanks.
>> >
>> > I wasn't sure what would be the most helpful so I've attached a few
>> > different
>> > dumps.
>> >
>> > image_dump = 1D array indirect piglit test, without this patch
>> > (Result=pass)
>> > image_dump2 = 2D array indirect piglit test, with this patch (Result=fail)
>> > image_dump3 = 1D array indirect piglit test, with this patch (Result=pass)
>> >
>> > image_dump4 = 1D array indirect piglit test, hardcoded register with 72
>> > offset
>> > (Result=pass)
>> > image_dump5 = 2D array indirect piglit test, hardcoded register with 72
>> > offset
>> > (Result=fail)
>> >
>> > image_dump4 vs image_dump5 is interesting because the output matches which
>> > is
>> > what I would have expected, but the result differs. Then with the offset
>> > below
>> > it seems to work as expected suggesting everything else is setup
>> > correctly.
>> >
>> > image_dump6 = 1D array indirect piglit test, hardcoded 72 offset in
>> > img_offset
>> > (Result=pass)
>> > image_dump7 = 2D array indirect piglit test, hardcoded 72 offset in
>> > img_offset
>> > (Result=pass)
>> >
>>
>> Yeah... The assembly output looks correct to me in the cases that fail.
>> AFAICT what all the failing cases have in common is that the array of
>> image uniforms is demoted to pull constants (see demote_pull_constants()
>> and move_uniform_array_access_to_pull_constants()),
>> so most likely
>> something goes wrong while doing that for multidimensional arrays. I
>> have the suspicion that this is the source of the problem:
>>
>> > --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
>> > +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
>> > @@ -226,6 +226,7 @@ fs_visitor::nir_setup_uniform(nir_variable *var)
>> > * our name.
>> > */
>> > unsigned index = var->data.driver_location;
>> > + bool set_image_location = true;
>> > for (unsigned u = 0; u < shader_prog->NumUniformStorage; u++) {
>> > struct gl_uniform_storage *storage = &shader_prog
>> > ->UniformStorage[u];
>> >
>> > @@ -244,7 +245,13 @@ fs_visitor::nir_setup_uniform(nir_variable *var)
>> > * because their size is driver-specific, so we need to allocate
>> > * space for them here at the end of the parameter array.
>> > */
>> > - var->data.driver_location = uniforms;
>> > + if (set_image_location) {
>> > + /* For arrays of arrays we only want to set this once at the
>> > base
>> > + * location.
>> > + */
>> > + var->data.driver_location = uniforms;
>> > + set_image_location = false;
>> > + }
>> > param_size[uniforms] =
>> > BRW_IMAGE_PARAM_SIZE * MAX2(storage->array_elements, 1);
>>
>> The assumption that this code was previously making was that a given
>> image array would be stored in a single gl_uniform_storage entry,
>> otherwise param_size[var->data.driver_location] won't match the real
>> size of the array and move_uniform_array_access_to_pull_constants() will
>> have no idea how large the array really is, so it will only be able to
>> move part of the array to the pull constant buffer and later on the
>> indirect array access will read past the end of the initialized area of
>> the constant buffer.
>
> Thanks for the reply. I'm still getting to know the i965 backend it would have
> taken me a while to get to this point, make a lot more sense now. The code
> below does the trick all of the indirect tests now pass.
>
> Thanks so much for your help :)
No problem. :)
>
>>
>> I think something like this would do what you want:
>>
>> > if (var->type->without_array()->is_image()) {
>> > /* Images don't get a valid location assigned by nir_lower_io()
>> > * because their size is driver-specific, so we need to allocate
>> > * space for them here at the end of the parameter array.
>> > */
>> > var->data.driver_location = uniforms;
>> > }
>> > [...]
>> > for (unsigned u = 0; u < shader_prog->NumUniformStorage; u++) {
>> > if (storage->type->is_image()) {
>> > param_size[var->data.driver_location] +=
>> > BRW_IMAGE_PARAM_SIZE * MAX2(storage->array_elements, 1);
>> > setup_image_uniform_values(storage);
>> > } else {
>> > [...]
>> > }
>> > }
>>
>> > [...]
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