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/*
* 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.h"
#include "nir_xfb_info.h"
#include "gl_nir_linker.h"
#include "linker_util.h"
#include "main/context.h"
#include "util/u_math.h"
/**
* This file does the linking of GLSL transform feedback using NIR.
*/
void
gl_nir_link_assign_xfb_resources(struct gl_context *ctx,
struct gl_shader_program *prog)
{
/*
* From ARB_gl_spirv spec:
*
* "- If the *Xfb* Execution Mode is set, any output variable that is at
* least partially captured:
* * must be decorated with an *XfbBuffer*, declaring the capturing buffer
* * must have at least one captured output variable in the capturing
* buffer decorated with an *XfbStride* (and all such *XfbStride* values
* for the capturing buffer must be equal)
* - If the *Xfb* Execution Mode is set, any captured output:
* * must be a non-structure decorated with *Offset* or a member of a
* structure whose type member is decorated with *Offset*"
*
* Note the "must be", meaning that explicit buffer, offset and stride are
* mandatory. So as this is intended to work with SPIR-V shaders we don't
* need to calculate the offset or the stride.
*/
struct gl_program *xfb_prog = prog->last_vert_prog;
if (xfb_prog == NULL)
return;
/* free existing varyings, if any */
for (unsigned i = 0; i < prog->TransformFeedback.NumVarying; i++)
free(prog->TransformFeedback.VaryingNames[i]);
free(prog->TransformFeedback.VaryingNames);
nir_xfb_info *xfb_info = NULL;
nir_xfb_varyings_info *varyings_info = NULL;
/* Find last stage before fragment shader */
for (int stage = MESA_SHADER_FRAGMENT - 1; stage >= 0; stage--) {
struct gl_linked_shader *sh = prog->_LinkedShaders[stage];
if (sh && stage != MESA_SHADER_TESS_CTRL) {
xfb_info = nir_gather_xfb_info_with_varyings(sh->Program->nir, NULL, &varyings_info);
break;
}
}
struct gl_transform_feedback_info *linked_xfb =
rzalloc(xfb_prog, struct gl_transform_feedback_info);
xfb_prog->sh.LinkedTransformFeedback = linked_xfb;
if (!xfb_info) {
prog->TransformFeedback.NumVarying = 0;
linked_xfb->NumOutputs = 0;
linked_xfb->NumVarying = 0;
linked_xfb->ActiveBuffers = 0;
return;
}
for (unsigned buf = 0; buf < MAX_FEEDBACK_BUFFERS; buf++)
prog->TransformFeedback.BufferStride[buf] = xfb_info->buffers[buf].stride;
prog->TransformFeedback.NumVarying = varyings_info->varying_count;
prog->TransformFeedback.VaryingNames =
malloc(sizeof(GLchar *) * varyings_info->varying_count);
linked_xfb->Outputs =
rzalloc_array(xfb_prog,
struct gl_transform_feedback_output,
xfb_info->output_count);
linked_xfb->NumOutputs = xfb_info->output_count;
linked_xfb->Varyings =
rzalloc_array(xfb_prog,
struct gl_transform_feedback_varying_info,
varyings_info->varying_count);
linked_xfb->NumVarying = varyings_info->varying_count;
int buffer_index = 0; /* Corresponds to GL_TRANSFORM_FEEDBACK_BUFFER_INDEX */
int xfb_buffer =
(varyings_info->varying_count > 0) ?
xfb_info->outputs[0].buffer : 0;
for (unsigned i = 0; i < varyings_info->varying_count; i++) {
nir_xfb_varying_info *xfb_varying = &varyings_info->varyings[i];
/* From ARB_gl_spirv spec:
*
* "19. How should the program interface query operations behave for
* program objects created from SPIR-V shaders?
*
* DISCUSSION: we previously said we didn't need reflection to work
* for SPIR-V shaders (at least for the first version), however we
* are left with specifying how it should "not work". The primary
* issue is that SPIR-V binaries are not required to have names
* associated with variables. They can be associated in debug
* information, but there is no requirement for that to be present,
* and it should not be relied upon."
*
* Options:"
*
* <skip>
*
* "RESOLVED. Pick (c), but also allow debug names to be returned
* if an implementation wants to."
*
* So names are considered optional debug info, so the linker needs to
* work without them, and returning them is optional. For simplicity at
* this point we are ignoring names
*/
prog->TransformFeedback.VaryingNames[i] = NULL;
if (xfb_buffer != xfb_varying->buffer) {
buffer_index++;
xfb_buffer = xfb_varying->buffer;
}
struct gl_transform_feedback_varying_info *varying =
linked_xfb->Varyings + i;
/* ARB_gl_spirv: see above. */
varying->Name = NULL;
varying->Type = glsl_get_gl_type(xfb_varying->type);
varying->BufferIndex = buffer_index;
varying->Size = glsl_type_is_array(xfb_varying->type) ?
glsl_get_length(xfb_varying->type) : 1;
varying->Offset = xfb_varying->offset;
}
for (unsigned i = 0; i < xfb_info->output_count; i++) {
nir_xfb_output_info *xfb_output = &xfb_info->outputs[i];
struct gl_transform_feedback_output *output =
linked_xfb->Outputs + i;
output->OutputRegister = xfb_output->location;
output->OutputBuffer = xfb_output->buffer;
output->NumComponents = util_bitcount(xfb_output->component_mask);
output->StreamId = xfb_info->buffer_to_stream[xfb_output->buffer];
output->DstOffset = xfb_output->offset / 4;
output->ComponentOffset = xfb_output->component_offset;
}
/* Make sure MaxTransformFeedbackBuffers is <= 32 so the bitmask for
* tracking the number of buffers doesn't overflow.
*/
unsigned buffers = 0;
assert(ctx->Const.MaxTransformFeedbackBuffers <= sizeof(buffers) * 8);
for (unsigned buf = 0; buf < MAX_FEEDBACK_BUFFERS; buf++) {
if (xfb_info->buffers[buf].stride > 0) {
linked_xfb->Buffers[buf].Stride = xfb_info->buffers[buf].stride / 4;
linked_xfb->Buffers[buf].NumVaryings = xfb_info->buffers[buf].varying_count;
buffers |= 1 << buf;
}
}
linked_xfb->ActiveBuffers = buffers;
ralloc_free(xfb_info);
}
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