[Mesa-dev] [PATCH v3] nir/linker: Add the start of a pure-NIR linker for XFB
Alejandro Piñeiro
apinheiro at igalia.com
Tue Jul 24 13:29:47 UTC 2018
From: Neil Roberts <nroberts at igalia.com>
v2: ignore names on purpose, for consistency with other places where
we are doing the same (Alejandro)
v3: changes proposed by Timothy Arceri, implemented by Alejandro Piñeiro:
* Remove redundant 'struct active_xfb_varying'
* Update several comments, including spec quotes if needed
* Rename struct 'active_xfb_varying_array' to 'active_xfb_varyings'
* Rename variable 'array' to 'active_varyings'
* Replace one if condition for an assert (<MAX_FEEDBACK_BUFFERS)
* Remove BufferMode initialization (was already done)
Signed-off-by: Neil Roberts <nroberts at igalia.com>
Signed-off-by: Alejandro Piñeiro <apinheiro at igalia.com>
---
src/compiler/Makefile.sources | 1 +
src/compiler/glsl/gl_nir_link_xfb.c | 317 ++++++++++++++++++++++++++++++++++++
src/compiler/glsl/gl_nir_linker.h | 3 +
src/compiler/glsl/meson.build | 1 +
4 files changed, 322 insertions(+)
create mode 100644 src/compiler/glsl/gl_nir_link_xfb.c
diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
index db4dd1e89f4..fe9f607d2b1 100644
--- a/src/compiler/Makefile.sources
+++ b/src/compiler/Makefile.sources
@@ -31,6 +31,7 @@ LIBGLSL_FILES = \
glsl/gl_nir_link_atomics.c \
glsl/gl_nir_link_uniform_initializers.c \
glsl/gl_nir_link_uniforms.c \
+ glsl/gl_nir_link_xfb.c \
glsl/gl_nir_linker.c \
glsl/gl_nir_linker.h \
glsl/gl_nir.h \
diff --git a/src/compiler/glsl/gl_nir_link_xfb.c b/src/compiler/glsl/gl_nir_link_xfb.c
new file mode 100644
index 00000000000..4703ac43400
--- /dev/null
+++ b/src/compiler/glsl/gl_nir_link_xfb.c
@@ -0,0 +1,317 @@
+/*
+ * 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 "gl_nir_linker.h"
+#include "ir_uniform.h" /* for gl_uniform_storage */
+#include "linker_util.h"
+#include "main/context.h"
+
+/*
+ * This file does the linking of GLSL transform feedback using NIR.
+ *
+ * Note: This linking pass is currently tailored for ARB_gl_spirv needs and
+ * particularities.
+ */
+
+struct active_xfb_buffer {
+ GLuint stride;
+ GLuint num_varyings;
+};
+
+struct active_xfb_varyings {
+ unsigned num_varyings;
+ unsigned num_outputs;
+ unsigned buffer_size;
+ struct nir_variable **varyings;
+ struct active_xfb_buffer buffers[MAX_FEEDBACK_BUFFERS];
+};
+
+static unsigned
+get_num_outputs(nir_variable *var)
+{
+ return glsl_count_attribute_slots(var->type,
+ false /* is_vertex_input */);
+}
+
+static void
+add_xfb_varying(struct active_xfb_varyings *active_varyings,
+ nir_variable *var)
+{
+ if (active_varyings->num_varyings >= active_varyings->buffer_size) {
+ if (active_varyings->buffer_size == 0)
+ active_varyings->buffer_size = 1;
+ else
+ active_varyings->buffer_size *= 2;
+
+ active_varyings->varyings = realloc(active_varyings->varyings,
+ sizeof(nir_variable*) *
+ active_varyings->buffer_size);
+ }
+
+ active_varyings->varyings[active_varyings->num_varyings++] = var;
+
+ active_varyings->num_outputs += get_num_outputs(var);
+}
+
+static int
+cmp_xfb_offset(const void *x_generic, const void *y_generic)
+{
+ const nir_variable *const *x = x_generic;
+ const nir_variable *const *y = y_generic;
+
+ if ((*x)->data.xfb_buffer != (*y)->data.xfb_buffer)
+ return (*x)->data.xfb_buffer - (*y)->data.xfb_buffer;
+ return (*x)->data.offset - (*y)->data.offset;
+}
+
+static void
+get_active_xfb_varyings(struct gl_shader_program *prog,
+ struct active_xfb_varyings *active_varyings)
+{
+ for (unsigned i = 0; i < MESA_SHADER_STAGES; ++i) {
+ struct gl_linked_shader *sh = prog->_LinkedShaders[i];
+ if (sh == NULL)
+ continue;
+
+ nir_shader *nir = sh->Program->nir;
+
+ nir_foreach_variable(var, &nir->outputs) {
+ if (var->data.explicit_xfb_buffer &&
+ var->data.explicit_xfb_stride) {
+ assert(var->data.xfb_buffer < MAX_FEEDBACK_BUFFERS);
+ active_varyings->buffers[var->data.xfb_buffer].stride =
+ var->data.xfb_stride;
+ }
+
+ if (!var->data.explicit_xfb_buffer ||
+ !var->data.explicit_offset)
+ continue;
+
+ active_varyings->buffers[var->data.xfb_buffer].num_varyings++;
+
+ add_xfb_varying(active_varyings, var);
+ }
+ }
+
+ /* The xfb_offset qualifier does not have to be used in increasing order
+ * however some drivers expect to receive the list of transform feedback
+ * declarations in order so sort it now for convenience.
+ */
+ qsort(active_varyings->varyings,
+ active_varyings->num_varyings,
+ sizeof(*active_varyings->varyings),
+ cmp_xfb_offset);
+}
+
+static unsigned
+add_varying_outputs(nir_variable *var,
+ const struct glsl_type *type,
+ unsigned location_offset,
+ unsigned dest_offset,
+ struct gl_transform_feedback_output *output)
+{
+ unsigned num_outputs = 0;
+
+ 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);
+ unsigned component_slots = glsl_get_component_slots(child_type);
+
+ for (unsigned i = 0; i < length; i++) {
+ unsigned child_outputs = add_varying_outputs(var,
+ child_type,
+ location_offset,
+ dest_offset,
+ output + num_outputs);
+ num_outputs += child_outputs;
+ location_offset += child_outputs;
+ dest_offset += component_slots;
+ }
+ } 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);
+ unsigned child_outputs = add_varying_outputs(var,
+ child_type,
+ location_offset,
+ dest_offset,
+ output + num_outputs);
+ num_outputs += child_outputs;
+ location_offset += child_outputs;
+ dest_offset += glsl_get_component_slots(child_type);
+ }
+ } else {
+ unsigned location = var->data.location + location_offset;
+ unsigned location_frac = var->data.location_frac;
+ unsigned num_components = glsl_get_component_slots(type);
+
+ while (num_components > 0) {
+ unsigned output_size = MIN2(num_components, 4 - location_frac);
+
+ output->OutputRegister = location;
+ output->OutputBuffer = var->data.xfb_buffer;
+ output->NumComponents = output_size;
+ output->StreamId = var->data.stream;
+ output->DstOffset = var->data.offset / 4 + dest_offset;
+ output->ComponentOffset = location_frac;
+
+ dest_offset += output_size;
+ num_components -= output_size;
+ num_outputs++;
+ output++;
+ location++;
+ location_frac = 0;
+ }
+ }
+
+ return num_outputs;
+}
+
+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);
+
+ struct active_xfb_varyings active_varyings = { 0 };
+
+ get_active_xfb_varyings(prog, &active_varyings);
+
+ for (unsigned buf = 0; buf < MAX_FEEDBACK_BUFFERS; buf++)
+ prog->TransformFeedback.BufferStride[buf] = active_varyings.buffers[buf].stride;
+
+ prog->TransformFeedback.NumVarying = active_varyings.num_varyings;
+ prog->TransformFeedback.VaryingNames =
+ malloc(sizeof(GLchar *) * active_varyings.num_varyings);
+
+ struct gl_transform_feedback_info *linked_xfb =
+ rzalloc(xfb_prog, struct gl_transform_feedback_info);
+ xfb_prog->sh.LinkedTransformFeedback = linked_xfb;
+
+ linked_xfb->Outputs =
+ rzalloc_array(xfb_prog,
+ struct gl_transform_feedback_output,
+ active_varyings.num_outputs);
+ linked_xfb->NumOutputs = active_varyings.num_outputs;
+
+ linked_xfb->Varyings =
+ rzalloc_array(xfb_prog,
+ struct gl_transform_feedback_varying_info,
+ active_varyings.num_varyings);
+ linked_xfb->NumVarying = active_varyings.num_varyings;
+
+ for (unsigned i = 0, output_pos = 0; i < active_varyings.num_varyings; i++) {
+ struct nir_variable *var = active_varyings.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;
+
+ struct gl_transform_feedback_output *output =
+ linked_xfb->Outputs + output_pos;
+ unsigned varying_outputs = add_varying_outputs(var,
+ var->type,
+ 0, /* location_offset */
+ 0, /* dest_offset */
+ output);
+ assert(varying_outputs == get_num_outputs(var));
+ output_pos += varying_outputs;
+
+ 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(var->type);
+ varying->BufferIndex = var->data.xfb_buffer;
+ varying->Size = glsl_get_length(var->type);
+ varying->Offset = var->data.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 (active_varyings.buffers[buf].stride > 0) {
+ linked_xfb->Buffers[buf].Stride = active_varyings.buffers[buf].stride / 4;
+ linked_xfb->Buffers[buf].NumVaryings = active_varyings.buffers[buf].num_varyings;
+ buffers |= 1 << buf;
+ }
+ }
+
+ linked_xfb->ActiveBuffers = buffers;
+
+ free(active_varyings.varyings);
+}
diff --git a/src/compiler/glsl/gl_nir_linker.h b/src/compiler/glsl/gl_nir_linker.h
index e1d493071ea..29ca27d3df8 100644
--- a/src/compiler/glsl/gl_nir_linker.h
+++ b/src/compiler/glsl/gl_nir_linker.h
@@ -43,6 +43,9 @@ void nir_build_program_resource_list(struct gl_context *ctx,
void gl_nir_link_assign_atomic_counter_resources(struct gl_context *ctx,
struct gl_shader_program *prog);
+void gl_nir_link_assign_xfb_resources(struct gl_context *ctx,
+ struct gl_shader_program *prog);
+
#ifdef __cplusplus
} /* extern "C" */
#endif
diff --git a/src/compiler/glsl/meson.build b/src/compiler/glsl/meson.build
index 96536b80168..45f2453b775 100644
--- a/src/compiler/glsl/meson.build
+++ b/src/compiler/glsl/meson.build
@@ -72,6 +72,7 @@ files_libglsl = files(
'gl_nir_link_atomics.c',
'gl_nir_link_uniform_initializers.c',
'gl_nir_link_uniforms.c',
+ 'gl_nir_link_xfb.c',
'gl_nir_linker.c',
'gl_nir_linker.h',
'gl_nir.h',
--
2.14.1
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