We'll need this in a moment. Ken's implementation, lightly edited for
Panfrost.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzw...@collabora.com>
Suggested-by: Kenneth Graunke <kenn...@whitecape.org>
---
src/gallium/drivers/panfrost/pan_context.c | 40 ++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/src/gallium/drivers/panfrost/pan_context.c
b/src/gallium/drivers/panfrost/pan_context.c
index 5e182fec564..2d7e417bb27 100644
--- a/src/gallium/drivers/panfrost/pan_context.c
+++ b/src/gallium/drivers/panfrost/pan_context.c
@@ -1,6 +1,7 @@
/*
* © Copyright 2018 Alyssa Rosenzweig
* Copyright © 2014-2017 Broadcom
+ * Copyright (C) 2017 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
@@ -1907,6 +1908,45 @@ panfrost_variant_matches(
return true;
}
+/**
+ * Fix an uncompiled shader's stream output info, and produce a bitmask
+ * of which VARYING_SLOT_* are captured for stream output.
+ *
+ * Core Gallium stores output->register_index as a "slot" number, where
+ * slots are assigned consecutively to all outputs in info->outputs_written.
+ * This naive packing of outputs doesn't work for us - we too have slots,
+ * but the layout is defined by the VUE map, which we won't have until we
+ * compile a specific shader variant. So, we remap these and simply store
+ * VARYING_SLOT_* in our copy's output->register_index fields.
+ *
+ * We then produce a bitmask of outputs which are used for SO.
+ *
+ * Implementation from iris.
+ */
+
+static uint64_t
+update_so_info(struct pipe_stream_output_info *so_info,
+ uint64_t outputs_written)
+{
+ uint64_t so_outputs = 0;
+ uint8_t reverse_map[64] = {};
+ unsigned slot = 0;
+
+ while (outputs_written)
+ reverse_map[slot++] = u_bit_scan64(&outputs_written);
+
+ for (unsigned i = 0; i < so_info->num_outputs; i++) {
+ struct pipe_stream_output *output = &so_info->output[i];
+
+ /* Map Gallium's condensed "slots" back to real VARYING_SLOT_*
enums */
+ output->register_index = reverse_map[output->register_index];
+
+ so_outputs |= 1ull << output->register_index;
+ }
+
+ return so_outputs;
+}
+
static void
panfrost_bind_shader_state(
struct pipe_context *pctx,
--
2.20.1
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