[Mesa-dev] [RFC 1/2] nir: lower-indirect-io pass
Rob Clark
robdclark at gmail.com
Thu Mar 24 19:04:54 UTC 2016
From: Rob Clark <robclark at freedesktop.org>
Prior to running nir_lower_io_types (next patch), we need to eliminate
indirect load_input/store_output. This can either be done via
nir_lower_indirect_derefs (for hw which does not support indirect var
access) or this pass (for hw which does).
---
src/compiler/Makefile.sources | 1 +
src/compiler/nir/nir.h | 2 +
src/compiler/nir/nir_lower_indirect_io.c | 151 +++++++++++++++++++++++++++++++
3 files changed, 154 insertions(+)
create mode 100644 src/compiler/nir/nir_lower_indirect_io.c
diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
index 99fd9fa..b1e3886 100644
--- a/src/compiler/Makefile.sources
+++ b/src/compiler/Makefile.sources
@@ -194,6 +194,7 @@ NIR_FILES = \
nir/nir_lower_locals_to_regs.c \
nir/nir_lower_idiv.c \
nir/nir_lower_indirect_derefs.c \
+ nir/nir_lower_indirect_io.c \
nir/nir_lower_io.c \
nir/nir_lower_outputs_to_temporaries.c \
nir/nir_lower_passthrough_edgeflags.c \
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index ed20dcd..297ca3b 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2149,6 +2149,8 @@ void nir_lower_io(nir_shader *shader,
nir_src *nir_get_io_offset_src(nir_intrinsic_instr *instr);
nir_src *nir_get_io_vertex_index_src(nir_intrinsic_instr *instr);
+void nir_lower_indirect_io(nir_shader *shader);
+
void nir_lower_vars_to_ssa(nir_shader *shader);
bool nir_remove_dead_variables(nir_shader *shader);
diff --git a/src/compiler/nir/nir_lower_indirect_io.c b/src/compiler/nir/nir_lower_indirect_io.c
new file mode 100644
index 0000000..e24c3a5
--- /dev/null
+++ b/src/compiler/nir/nir_lower_indirect_io.c
@@ -0,0 +1,151 @@
+/*
+ * Copyright © 2016 Red Hat
+ *
+ * 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_builder.h"
+
+/* Lower indirect load_input/store_output to a direct copy to a local which
+ * is indirectly accessed. Use this (instead of nir_lower_indirect_derefs)
+ * if your hardware supports native indirect access, before running
+ * nir_lower_io_types. This ensures that all inputs/outputs can be lowered
+ * to non-struct/array/mat types regardless of indirect access.
+ *
+ * NOTE: you'll need a split_var_copies pass somewhere after this and before
+ * lower_var_copies.
+ */
+
+
+struct lower_indirect_io_state {
+ nir_shader *shader;
+ nir_function_impl *impl;
+};
+
+static bool
+is_indirect(nir_deref *tail)
+{
+ while (tail != NULL) {
+ if (tail->deref_type == nir_deref_type_array) {
+ nir_deref_array *deref_array = nir_deref_as_array(tail);
+ if (deref_array->deref_array_type == nir_deref_array_type_indirect)
+ return true;
+ }
+ tail = tail->child;
+ }
+ return false;
+}
+
+static bool
+lower_indirect_io_block(nir_block *block, void *void_state)
+{
+ struct lower_indirect_io_state *state = void_state;
+ nir_cursor cursor;
+
+ nir_foreach_instr_safe(block, instr) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
+
+ if ((intr->intrinsic != nir_intrinsic_load_var) &&
+ (intr->intrinsic != nir_intrinsic_store_var))
+ continue;
+
+ nir_variable *var = intr->variables[0]->var;
+ nir_variable_mode mode = var->data.mode;
+
+ if ((mode != nir_var_shader_in) && (mode != nir_var_shader_out))
+ continue;
+
+ if (!is_indirect(&intr->variables[0]->deref))
+ continue;
+
+ /* for either input or output, convert existing var to local (which
+ * means we don't have to deal with any remaining load_var/store_var
+ * references to it), and create a new var to replace it as an input/
+ * output:
+ */
+ nir_variable *nvar = nir_variable_clone(var, state->shader);
+
+ /* remove existing var from input/output list: */
+ exec_node_remove(&var->node);
+ exec_node_self_link(&var->node); /* no delinit() :-( */
+
+ /* and add make into a local: */
+ var->data.mode = nir_var_local;
+ var->data.location = 0;
+ var->data.driver_location = 0;
+ exec_list_push_tail(&state->impl->locals, &var->node);
+
+ /* rename the (now global) variable to make nir_print's more clear: */
+ ralloc_free(var->name);
+ var->name = ralloc_asprintf(var, "shadow_%s", nvar->name);
+
+ nir_intrinsic_instr *copy =
+ nir_intrinsic_instr_create(state->shader, nir_intrinsic_copy_var);
+
+ if (mode == nir_var_shader_in) {
+ /* insert new input plus copy_var at head of shader to copy into
+ * original var:
+ */
+ exec_list_push_tail(&state->shader->inputs, &nvar->node);
+ cursor = nir_before_block(nir_start_block(state->impl));
+ copy->variables[0] = nir_deref_var_create(copy, var); /* dst */
+ copy->variables[1] = nir_deref_var_create(copy, nvar); /* src */
+ nir_instr_insert(cursor, ©->instr);
+ } else if (mode == nir_var_shader_out) {
+ /* insert new output plus copy_var at tail of shader to copy from
+ * original var:
+ */
+ exec_list_push_tail(&state->shader->outputs, &nvar->node);
+ cursor = nir_after_block(state->impl->end_block);
+ copy->variables[0] = nir_deref_var_create(copy, nvar); /* dst */
+ copy->variables[1] = nir_deref_var_create(copy, var); /* src */
+ nir_instr_insert(cursor, ©->instr);
+ }
+ }
+
+ return true;
+}
+
+static void
+lower_indirect_io_impl(nir_function_impl *impl)
+{
+ struct lower_indirect_io_state state;
+
+ state.shader = impl->function->shader;
+ state.impl = impl;
+
+ nir_foreach_block(impl, lower_indirect_io_block, &state);
+
+ nir_metadata_preserve(impl, nir_metadata_block_index |
+ nir_metadata_dominance);
+}
+
+void
+nir_lower_indirect_io(nir_shader *shader)
+{
+ nir_foreach_function(shader, function) {
+ if (function->impl)
+ lower_indirect_io_impl(function->impl);
+ }
+}
--
2.5.5
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