[Mesa-dev] [PATCH] nir: Add a pass for gathering transform feedback info
Jason Ekstrand
jason at jlekstrand.net
Fri Oct 5 15:44:11 UTC 2018
On Fri, Oct 5, 2018 at 10:34 AM Alejandro Piñeiro <apinheiro at igalia.com>
wrote:
> On 05/10/18 16:13, Jason Ekstrand wrote:
> > This is different from the GL_ARB_spirv pass because it generates a much
> > simpler data structure that isn't tied to OpenGL and mtypes.h.
>
> I have just skimmed it (don't have time right now for a full check, will
> take a deeper look next Monday), but FWIW, the GL_ARB_spirv pass does a
> initial mtypes-free info gathering (get_active_xfb_varyings) and then it
> uses that info to fill-up the OpenGL specific mtypes.h. In fact, if we
> just compare the initial GL_ARB_spirv gathering with this new pass, your
> pass seems more complete, and with more checks. So I was wondering if it
> would be possible to remove some code on the GL_ARB_spirv pass and use
> this new pass instead. Did you check if that would be possible? If not
> I'm willing to check next week.
>
I didn't really look into that too much. When drafting this one, I did
base it somewhat on the GL_ARB_spirv pass so I"m not surprised it's
similar. At the time, I was just trying to get something working and
wasn't too worried about code duplication. If we can use this pass for
GL_ARB_spirv, that'd be fantastic. If we do go that route, however, we may
want to do something better than assert() for the error handling.
> > ---
> > src/compiler/Makefile.sources | 4 +-
> > src/compiler/nir/meson.build | 2 +
> > src/compiler/nir/nir_gather_xfb_info.c | 150 +++++++++++++++++++++++++
> > src/compiler/nir/nir_xfb_info.h | 59 ++++++++++
> > 4 files changed, 214 insertions(+), 1 deletion(-)
> > create mode 100644 src/compiler/nir/nir_gather_xfb_info.c
> > create mode 100644 src/compiler/nir/nir_xfb_info.h
> >
> > diff --git a/src/compiler/Makefile.sources
> b/src/compiler/Makefile.sources
> > index d3b06564832..46ed5e47b46 100644
> > --- a/src/compiler/Makefile.sources
> > +++ b/src/compiler/Makefile.sources
> > @@ -216,6 +216,7 @@ NIR_FILES = \
> > nir/nir_format_convert.h \
> > nir/nir_from_ssa.c \
> > nir/nir_gather_info.c \
> > + nir/nir_gather_xfb_info.c \
> > nir/nir_gs_count_vertices.c \
> > nir/nir_inline_functions.c \
> > nir/nir_instr_set.c \
> > @@ -307,7 +308,8 @@ NIR_FILES = \
> > nir/nir_validate.c \
> > nir/nir_vla.h \
> > nir/nir_worklist.c \
> > - nir/nir_worklist.h
> > + nir/nir_worklist.h \
> > + nir/nir_xfb_info.h
> >
> > SPIRV_GENERATED_FILES = \
> > spirv/spirv_info.c \
> > diff --git a/src/compiler/nir/meson.build b/src/compiler/nir/meson.build
> > index 090aa7a628f..b416e561eb0 100644
> > --- a/src/compiler/nir/meson.build
> > +++ b/src/compiler/nir/meson.build
> > @@ -100,6 +100,7 @@ files_libnir = files(
> > 'nir_format_convert.h',
> > 'nir_from_ssa.c',
> > 'nir_gather_info.c',
> > + 'nir_gather_xfb_info.c',
> > 'nir_gs_count_vertices.c',
> > 'nir_inline_functions.c',
> > 'nir_instr_set.c',
> > @@ -192,6 +193,7 @@ files_libnir = files(
> > 'nir_vla.h',
> > 'nir_worklist.c',
> > 'nir_worklist.h',
> > + 'nir_xfb_info.h',
> > '../spirv/GLSL.ext.AMD.h',
> > '../spirv/GLSL.std.450.h',
> > '../spirv/gl_spirv.c',
> > diff --git a/src/compiler/nir/nir_gather_xfb_info.c
> b/src/compiler/nir/nir_gather_xfb_info.c
> > new file mode 100644
> > index 00000000000..a53703bb9bf
> > --- /dev/null
> > +++ b/src/compiler/nir/nir_gather_xfb_info.c
> > @@ -0,0 +1,150 @@
> > +/*
> > + * Copyright © 2018 Intel Corporation
> > + *
> > + * Permission is hereby granted, free of charge, to any person
> obtaining a
> > + * copy of this software and associated documentation files (the
> "Software"),
> > + * to deal in the Software without restriction, including without
> limitation
> > + * the rights to use, copy, modify, merge, publish, distribute,
> sublicense,
> > + * and/or sell copies of the Software, and to permit persons to whom the
> > + * Software is furnished to do so, subject to the following conditions:
> > + *
> > + * The above copyright notice and this permission notice (including the
> next
> > + * paragraph) shall be included in all copies or substantial portions
> of the
> > + * Software.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> EXPRESS OR
> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> MERCHANTABILITY,
> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
> SHALL
> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> OTHER
> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> ARISING
> > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> DEALINGS
> > + * IN THE SOFTWARE.
> > + */
> > +
> > +#include "nir_xfb_info.h"
> > +
> > +#include <util/u_math.h>
> > +
> > +static void
> > +add_var_xfb_outputs(nir_xfb_info *xfb,
> > + nir_variable *var,
> > + unsigned *location,
> > + unsigned *offset,
> > + const struct glsl_type *type)
> > +{
> > + if (glsl_type_is_array(type) || glsl_type_is_matrix(type)) {
> > + unsigned length = glsl_get_length(type);
> > + const struct glsl_type *child_type = glsl_get_array_element(type);
> > + for (unsigned i = 0; i < length; i++)
> > + add_var_xfb_outputs(xfb, var, location, offset, child_type);
> > + } else if (glsl_type_is_struct(type)) {
> > + unsigned length = glsl_get_length(type);
> > + for (unsigned i = 0; i < length; i++) {
> > + const struct glsl_type *child_type =
> glsl_get_struct_field(type, i);
> > + add_var_xfb_outputs(xfb, var, location, offset, child_type);
> > + }
> > + } else {
> > + assert(var->data.xfb_buffer < NIR_MAX_XFB_BUFFERS);
> > + if (xfb->buffers_written & (1 << var->data.xfb_buffer)) {
> > + assert(xfb->strides[var->data.xfb_buffer] ==
> var->data.xfb_stride);
> > + assert(xfb->buffer_to_stream[var->data.xfb_buffer] ==
> var->data.stream);
> > + } else {
> > + xfb->buffers_written |= (1 << var->data.xfb_buffer);
> > + xfb->strides[var->data.xfb_buffer] = var->data.xfb_stride;
> > + xfb->buffer_to_stream[var->data.xfb_buffer] = var->data.stream;
> > + }
> > +
> > + assert(var->data.stream < NIR_MAX_XFB_STREAMS);
> > + xfb->streams_written |= (1 << var->data.stream);
> > +
> > + unsigned comp_slots = glsl_get_component_slots(type);
> > + unsigned attrib_slots = DIV_ROUND_UP(comp_slots, 4);
> > + assert(attrib_slots == glsl_count_attribute_slots(type, false));
> > +
> > + /* Ensure that we don't have, for instance, a dvec2 with a
> location_frac
> > + * of 2 which would make it crass a location boundary even though
> it
> > + * fits in a single slot. However, you can have a dvec3 which
> crosses
> > + * the slot boundary with a location_frac of 2.
> > + */
> > + assert(DIV_ROUND_UP(var->data.location_frac + comp_slots, 4) ==
> attrib_slots);
> > +
> > + assert(var->data.location_frac + comp_slots <= 8);
> > + uint8_t comp_mask = ((1 << comp_slots) - 1) <<
> var->data.location_frac;
> > +
> > + assert(attrib_slots <= 2);
> > + for (unsigned s = 0; s < attrib_slots; s++) {
> > + nir_xfb_output_info *output =
> &xfb->outputs[xfb->output_count++];
> > +
> > + output->buffer = var->data.xfb_buffer;
> > + output->offset = *offset;
> > + output->location = *location;
> > + output->component_mask = (comp_mask >> (s * 4)) & 0xf;
> > +
> > + (*location)++;
> > + *offset += comp_slots * 4;
> > + }
> > + }
> > +}
> > +
> > +static int
> > +compare_xfb_output_offsets(const void *_a, const void *_b)
> > +{
> > + const nir_xfb_output_info *a = _a, *b = _b;
> > + return a->offset - b->offset;
> > +}
>
> We have this same comparison on link_varyings.c and gl_nir_link_xfb.
> Not sure how I feel about having the same function three times. I would
> really hope that my previous comment to reuse code to be true.
>
Yeah, if we can re-use some stuff, that'd be great. On the other hand,
it's six lines of code which ammount to one interesting line so I'm not too
worried about the duplication. :-)
--Jason
> > +
> > +nir_xfb_info *
> > +nir_gather_xfb_info(const nir_shader *shader, void *mem_ctx)
> > +{
> > + assert(shader->info.stage == MESA_SHADER_VERTEX ||
> > + shader->info.stage == MESA_SHADER_TESS_EVAL ||
> > + shader->info.stage == MESA_SHADER_GEOMETRY);
> > +
> > + /* Compute the number of outputs we have. This is simply the number
> of
> > + * cumulative locations consumed by all the variables. If a
> location is
> > + * represented by multiple variables, then they each count
> separately in
> > + * number of outputs.
> > + */
> > + unsigned num_outputs = 0;
> > + nir_foreach_variable(var, &shader->outputs) {
> > + if (var->data.explicit_xfb_buffer ||
> > + var->data.explicit_xfb_stride) {
> > + assert(var->data.explicit_xfb_buffer &&
> > + var->data.explicit_xfb_stride &&
> > + var->data.explicit_offset);
> > + num_outputs += glsl_count_attribute_slots(var->type, false);
> > + }
> > + }
> > + if (num_outputs == 0)
> > + return NULL;
> > +
> > + nir_xfb_info *xfb = rzalloc_size(mem_ctx,
> nir_xfb_info_size(num_outputs));
> > +
> > + /* Walk the list of outputs and add them to the array */
> > + nir_foreach_variable(var, &shader->outputs) {
> > + if (var->data.explicit_xfb_buffer ||
> > + var->data.explicit_xfb_stride) {
> > + unsigned logcation = var->data.location;
> > + unsigned offset = var->data.offset;
> > + add_var_xfb_outputs(xfb, var, &location, &offset, var->type);
> > + }
> > + }
> > + assert(xfb->output_count == num_outputs);
> > +
> > + /* Everything is easier in the state setup code if the list is
> sorted in
> > + * order of output offset.
> > + */
> > + qsort(xfb->outputs, xfb->output_count, sizeof(xfb->outputs[0]),
> > + compare_xfb_output_offsets);
> > +
> > + /* Finally, do a sanity check */
> > + unsigned max_offset[NIR_MAX_XFB_BUFFERS] = { };
> > + for (unsigned i = 0; i < xfb->output_count; i++) {
> > + assert(xfb->outputs[i].offset >=
> max_offset[xfb->outputs[i].buffer]);
> > + assert(xfb->outputs[i].component_mask != 0);
> > + unsigned slots = util_bitcount(xfb->outputs[i].component_mask);
> > + max_offset[xfb->outputs[i].buffer] = xfb->outputs[i].offset +
> slots * 4;
> > + }
> > +
> > + return xfb;
> > +}
> > diff --git a/src/compiler/nir/nir_xfb_info.h
> b/src/compiler/nir/nir_xfb_info.h
> > new file mode 100644
> > index 00000000000..9b543df5f47
> > --- /dev/null
> > +++ b/src/compiler/nir/nir_xfb_info.h
> > @@ -0,0 +1,59 @@
> > +/*
> > + * Copyright © 2018 Intel Corporation
> > + *
> > + * Permission is hereby granted, free of charge, to any person
> obtaining a
> > + * copy of this software and associated documentation files (the
> "Software"),
> > + * to deal in the Software without restriction, including without
> limitation
> > + * the rights to use, copy, modify, merge, publish, distribute,
> sublicense,
> > + * and/or sell copies of the Software, and to permit persons to whom the
> > + * Software is furnished to do so, subject to the following conditions:
> > + *
> > + * The above copyright notice and this permission notice (including the
> next
> > + * paragraph) shall be included in all copies or substantial portions
> of the
> > + * Software.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> EXPRESS OR
> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> MERCHANTABILITY,
> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
> SHALL
> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> OTHER
> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> ARISING
> > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> DEALINGS
> > + * IN THE SOFTWARE.
> > + */
> > +
> > +#ifndef NIR_XFB_INFO_H
> > +#define NIR_XFB_INFO_H
> > +
> > +#include "nir.h"
> > +
> > +#define NIR_MAX_XFB_BUFFERS 4
> > +#define NIR_MAX_XFB_STREAMS 4
> > +
> > +typedef struct {
> > + uint8_t buffer;
> > + uint16_t offset;
> > + uint8_t location;
> > + uint8_t component_mask;
> > +} nir_xfb_output_info;
> > +
> > +typedef struct {
> > + uint8_t buffers_written;
> > + uint8_t streams_written;
> > +
> > + uint16_t strides[NIR_MAX_XFB_BUFFERS];
> > + uint8_t buffer_to_stream[NIR_MAX_XFB_STREAMS];
> > +
> > + uint16_t output_count;
> > + nir_xfb_output_info outputs[0];
> > +} nir_xfb_info;
> > +
> > +static inline size_t
> > +nir_xfb_info_size(uint16_t output_count)
> > +{
> > + return sizeof(nir_xfb_info) + sizeof(nir_xfb_output_info) *
> output_count;
> > +}
> > +
> > +nir_xfb_info *
> > +nir_gather_xfb_info(const nir_shader *shader, void *mem_ctx);
> > +
> > +#endif /* NIR_XFB_INFO_H */
>
>
>
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