#include "nir.h"
#include "nir_builder.h"
+#include "nir_deref.h"
struct lower_io_state {
nir_shader *shader;
nir_function_impl *entrypoint;
struct exec_list old_outputs;
struct exec_list old_inputs;
+
+ /* map from temporary to new input */
+ struct hash_table *input_map;
};
static void
}
}
+/* For fragment shader inputs, when we lower to temporaries we'll invalidate
+ * interpolateAt*() because now they'll be pointing to the temporary instead
+ * of the actual variable. Since the caller presumably doesn't support
+ * indirect indexing of inputs, we'll need to lower something like:
+ *
+ * in vec4 foo[3];
+ *
+ * ... = interpolateAtCentroid(foo[i]);
+ *
+ * to a sequence of interpolations that store to our temporary, then a
+ * load at the end:
+ *
+ * in vec4 foo[3];
+ * vec4 foo_tmp[3];
+ *
+ * foo_tmp[0] = interpolateAtCentroid(foo[0]);
+ * foo_tmp[1] = interpolateAtCentroid(foo[1]);
+ * ... = foo_tmp[i];
+ */
+
+/*
+ * Recursively emit the interpolation instructions. Here old_interp_deref
+ * refers to foo[i], temp_deref is foo_tmp[0/1], and new_interp_deref is
+ * foo[0/1].
+ */
+
+static void
+emit_interp(nir_builder *b, nir_deref_instr **old_interp_deref,
+ nir_deref_instr *temp_deref, nir_deref_instr *new_interp_deref,
+ nir_intrinsic_instr *interp)
+{
+ while (*old_interp_deref) {
+ switch ((*old_interp_deref)->deref_type) {
+ case nir_deref_type_struct:
+ temp_deref =
+ nir_build_deref_struct(b, temp_deref,
+ (*old_interp_deref)->strct.index);
+ new_interp_deref =
+ nir_build_deref_struct(b, new_interp_deref,
+ (*old_interp_deref)->strct.index);
+ break;
+ case nir_deref_type_array:
+ if (nir_src_is_const((*old_interp_deref)->arr.index)) {
+ temp_deref =
+ nir_build_deref_array(b, temp_deref,
+ (*old_interp_deref)->arr.index.ssa);
+ new_interp_deref =
+ nir_build_deref_array(b, new_interp_deref,
+ (*old_interp_deref)->arr.index.ssa);
+ break;
+ } else {
+ /* We have an indirect deref, so we have to emit interpolations
+ * for every index. Recurse in case we have an array of arrays.
+ */
+ unsigned length = glsl_get_length(temp_deref->type);
+ for (unsigned i = 0; i < length; i++) {
+ nir_deref_instr *new_temp =
+ nir_build_deref_array_imm(b, temp_deref, i);
+ nir_deref_instr *new_interp =
+ nir_build_deref_array_imm(b, new_interp_deref, i);
+
+ emit_interp(b, old_interp_deref + 1, new_temp, new_interp,
+ interp);
+ }
+
+ return;
+ }
+
+ case nir_deref_type_var:
+ case nir_deref_type_array_wildcard:
+ case nir_deref_type_ptr_as_array:
+ case nir_deref_type_cast:
+ unreachable("bad deref type");
+ }
+
+ old_interp_deref++;
+ }
+
+ /* Now that we've constructed a fully-qualified deref with all the indirect
+ * derefs replaced with direct ones, it's time to actually emit the new
+ * interpolation instruction.
+ */
+
+ nir_intrinsic_instr *new_interp =
+ nir_intrinsic_instr_create(b->shader, interp->intrinsic);
+
+ new_interp->src[0] = nir_src_for_ssa(&new_interp_deref->dest.ssa);
+ if (interp->intrinsic == nir_intrinsic_interp_deref_at_sample ||
+ interp->intrinsic == nir_intrinsic_interp_deref_at_offset) {
+ new_interp->src[1] = interp->src[1];
+ }
+
+ new_interp->num_components = interp->num_components;
+ nir_ssa_dest_init(&new_interp->instr, &new_interp->dest,
+ interp->dest.ssa.num_components,
+ interp->dest.ssa.bit_size, NULL);
+
+ nir_builder_instr_insert(b, &new_interp->instr);
+ nir_store_deref(b, temp_deref, &new_interp->dest.ssa,
+ (1 << interp->dest.ssa.num_components) - 1);
+}
+
+static void
+fixup_interpolation_instr(struct lower_io_state *state,
+ nir_intrinsic_instr *interp, nir_builder *b)
+{
+ nir_deref_path interp_path;
+ nir_deref_path_init(&interp_path, nir_src_as_deref(interp->src[0]), NULL);
+
+ b->cursor = nir_before_instr(&interp->instr);
+
+ /* The original interpolation instruction should contain a deref path
+ * starting with the original variable, which is now the temporary.
+ */
+ nir_deref_instr *temp_root = interp_path.path[0];
+
+ /* Fish out the newly-created input variable. */
+ assert(temp_root->deref_type == nir_deref_type_var);
+ struct hash_entry *entry = _mesa_hash_table_search(state->input_map,
+ temp_root->var);
+ assert(entry);
+ nir_variable *input = entry->data;
+ nir_deref_instr *input_root = nir_build_deref_var(b, input);
+
+ /* Emit the interpolation instructions. */
+ emit_interp(b, interp_path.path + 1, temp_root, input_root, interp);
+
+ /* Now the temporary contains the interpolation results, and we can just
+ * load from it. We can reuse the original deref, since it points to the
+ * correct part of the temporary.
+ */
+ nir_ssa_def *load = nir_load_deref(b, nir_src_as_deref(interp->src[0]));
+ nir_ssa_def_rewrite_uses(&interp->dest.ssa, nir_src_for_ssa(load));
+ nir_instr_remove(&interp->instr);
+
+ nir_deref_path_finish(&interp_path);
+}
+
+static void
+fixup_interpolation(struct lower_io_state *state, nir_function_impl *impl,
+ nir_builder *b)
+{
+ nir_foreach_block(block, impl) {
+ nir_foreach_instr_safe(instr, block) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *interp = nir_instr_as_intrinsic(instr);
+
+ if (interp->intrinsic == nir_intrinsic_interp_deref_at_centroid ||
+ interp->intrinsic == nir_intrinsic_interp_deref_at_sample ||
+ interp->intrinsic == nir_intrinsic_interp_deref_at_offset) {
+ fixup_interpolation_instr(state, interp, b);
+ }
+ }
+ }
+}
+
static void
emit_input_copies_impl(struct lower_io_state *state, nir_function_impl *impl)
{
nir_builder_init(&b, impl);
b.cursor = nir_before_block(nir_start_block(impl));
emit_copies(&b, &state->old_inputs, &state->shader->inputs);
+ if (state->shader->info.stage == MESA_SHADER_FRAGMENT)
+ fixup_interpolation(state, impl, &b);
}
}
state.shader = shader;
state.entrypoint = entrypoint;
+ state.input_map = _mesa_pointer_hash_table_create(NULL);
if (inputs)
exec_list_move_nodes_to(&shader->inputs, &state.old_inputs);
nir_foreach_variable(var, &state.old_inputs) {
nir_variable *input = create_shadow_temp(&state, var);
exec_list_push_tail(&shader->inputs, &input->node);
+ _mesa_hash_table_insert(state.input_map, var, input);
}
nir_foreach_function(function, shader) {
projects / mesa.git / commitdiff