[Mesa-dev] [PATCH 4/8] nir: add some helpers for doing linking
Timothy Arceri
tarceri at itsqueeze.com
Tue Sep 12 23:37:31 UTC 2017
The initial helpers as support for removing unused varyings between
stages.
---
src/compiler/Makefile.sources | 1 +
src/compiler/nir/nir.h | 6 ++
src/compiler/nir/nir_linking_helpers.c | 136 +++++++++++++++++++++++++++++++++
3 files changed, 143 insertions(+)
create mode 100644 src/compiler/nir/nir_linking_helpers.c
diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
index 0153df2d812..9c7f057eecf 100644
--- a/src/compiler/Makefile.sources
+++ b/src/compiler/Makefile.sources
@@ -203,6 +203,7 @@ NIR_FILES = \
nir/nir_instr_set.h \
nir/nir_intrinsics.c \
nir/nir_intrinsics.h \
+ nir/nir_linking_helpers.c \
nir/nir_liveness.c \
nir/nir_loop_analyze.c \
nir/nir_loop_analyze.h \
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index e52a1006896..1e89c74d14c 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2448,6 +2448,12 @@ void nir_shader_gather_info(nir_shader *shader, nir_function_impl *entrypoint);
void nir_assign_var_locations(struct exec_list *var_list, unsigned *size,
int (*type_size)(const struct glsl_type *));
+/* Some helpers to do very simple linking */
+bool nir_remove_unwritten_outputs(nir_shader *shader);
+bool nir_remove_unread_outputs(nir_shader *shader, uint64_t outputs_read);
+bool nir_remove_unused_varyings(nir_shader *producer, nir_shader *consumer);
+bool nir_compact_varyings(nir_shader *producer, nir_shader *consumer);
+
typedef enum {
/* If set, this forces all non-flat fragment shader inputs to be
* interpolated as if with the "sample" qualifier. This requires
diff --git a/src/compiler/nir/nir_linking_helpers.c b/src/compiler/nir/nir_linking_helpers.c
new file mode 100644
index 00000000000..d567aa713ad
--- /dev/null
+++ b/src/compiler/nir/nir_linking_helpers.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright © 2015 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 "util/set.h"
+#include "util/hash_table.h"
+
+/* This file contains various little helpers for doing simple linking in
+ * NIR. Eventually, we'll probably want a full-blown varying packing
+ * implementation in here. Right now, it just deletes unused things.
+ */
+
+static void
+find_live_tcs_outputs(nir_shader *shader, struct set *live)
+{
+ nir_foreach_function(function, shader) {
+ if (function->impl) {
+ nir_foreach_block(block, function->impl) {
+ nir_foreach_instr(instr, block) {
+ if (instr->type == nir_instr_type_intrinsic) {
+ nir_intrinsic_instr *intrin_instr =
+ nir_instr_as_intrinsic(instr);
+ if (intrin_instr->intrinsic == nir_intrinsic_load_var &&
+ intrin_instr->variables[0]->var->data.mode ==
+ nir_var_shader_out) {
+ _mesa_set_add(live, intrin_instr->variables[0]->var);
+ }
+ }
+ }
+ }
+ }
+ }
+}
+
+static bool
+remove_unused_io_vars(nir_shader *shader, struct exec_list *var_list,
+ uint64_t used_by_other_stage,
+ struct set *live_tcs_outputs)
+{
+ bool progress = false;
+
+ nir_foreach_variable_safe(var, var_list) {
+ /* TODO: add patch support */
+ if (var->data.patch)
+ continue;
+
+ if (var->data.location < VARYING_SLOT_VAR0 && var->data.location >= 0)
+ continue;
+
+ if (var->data.always_active_io)
+ continue;
+
+ if (!(used_by_other_stage &
+ nir_variable_get_io_mask(var, shader->stage))) {
+ /* Each TCS invocation can read data written by other TCS invocations,
+ * so even if the outputs are not used by the TES we must also make
+ * sure they are not read by the TCS before demoting them to globals.
+ */
+ if (live_tcs_outputs) {
+ assert(shader->stage == MESA_SHADER_TESS_CTRL &&
+ var->data.mode == nir_var_shader_out);
+
+ struct set_entry *entry = _mesa_set_search(live_tcs_outputs, var);
+ if (entry) {
+ continue;
+ }
+ }
+
+ /* This one is invalid, make it a global variable instead */
+ var->data.location = 0;
+ var->data.mode = nir_var_global;
+
+ exec_node_remove(&var->node);
+ exec_list_push_tail(&shader->globals, &var->node);
+
+ progress = true;
+ }
+ }
+
+ return progress;
+}
+
+bool
+nir_remove_unused_varyings(nir_shader *producer, nir_shader *consumer)
+{
+ assert(producer->stage != MESA_SHADER_FRAGMENT);
+ assert(consumer->stage != MESA_SHADER_VERTEX);
+
+ uint64_t read = 0, written = 0;
+
+ nir_foreach_variable(var, &producer->outputs)
+ written |= nir_variable_get_io_mask(var, producer->stage);
+
+ nir_foreach_variable(var, &consumer->inputs)
+ read |= nir_variable_get_io_mask(var, consumer->stage);
+
+ struct set *live_tcs_outputs;
+ if (producer->stage == MESA_SHADER_TESS_CTRL) {
+ live_tcs_outputs =
+ _mesa_set_create(NULL, _mesa_hash_pointer, _mesa_key_pointer_equal);
+ find_live_tcs_outputs(producer, live_tcs_outputs);
+ } else {
+ live_tcs_outputs = NULL;
+ }
+
+ bool progress = false;
+ progress = remove_unused_io_vars(producer, &producer->outputs, read,
+ live_tcs_outputs);
+
+ progress = remove_unused_io_vars(consumer, &consumer->inputs, written,
+ NULL) || progress;
+
+ _mesa_set_destroy(live_tcs_outputs, NULL);
+
+ return progress;
+}
--
2.13.5
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