pan/bi: Add liveness analysis pass

Now that all the guts are shared with Midgard, it's just a matter of
wiring it in.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4150>

src/panfrost/bifrost/bi_liveness.c

@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2020 Collabora, Ltd.
+ * Copyright (C) 2018-2019 Alyssa Rosenzweig <alyssa@rosenzweig.io>
+ *
+ * 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 "compiler.h"
+
+void
+bi_liveness_ins_update(uint16_t *live, bi_instruction *ins, unsigned max)
+{
+        /* live_in[s] = GEN[s] + (live_out[s] - KILL[s]) */
+
+        pan_liveness_kill(live, ins->dest, max, ins->writemask);
+
+        bi_foreach_src(ins, src) {
+                unsigned node = ins->src[src];
+                unsigned bytemask = bi_bytemask_of_read_components(ins, node);
+
+                pan_liveness_gen(live, node, max, bytemask);
+        }
+}
+
+static void
+bi_liveness_ins_update_wrap(uint16_t *live, void *ins, unsigned max)
+{
+        bi_liveness_ins_update(live, (bi_instruction *) ins, max);
+}
+
+void
+bi_compute_liveness(bi_context *ctx)
+{
+        if (ctx->has_liveness)
+                return;
+
+        pan_compute_liveness(&ctx->blocks, bi_max_temp(ctx), bi_liveness_ins_update_wrap);
+
+        ctx->has_liveness = true;
+}
+
+/* Once liveness data is no longer valid, call this */
+
+void
+bi_invalidate_liveness(bi_context *ctx)
+{
+        if (ctx->has_liveness)
+                pan_free_liveness(&ctx->blocks);
+
+        ctx->has_liveness = false;
+}
+
+bool
+bi_is_live_after(bi_context *ctx, bi_block *block, bi_instruction *start, int src)
+{
+        bi_compute_liveness(ctx);
+
+        /* Check whether we're live in the successors */
+
+        if (pan_liveness_get(block->base.live_out, src, bi_max_temp(ctx)))
+                return true;
+
+        /* Check the rest of the block for liveness */
+
+        bi_foreach_instr_in_block_from(block, ins, bi_next_op(start)) {
+                if (bi_has_arg(ins, src))
+                        return true;
+        }
+
+        return false;
+}

src/panfrost/bifrost/compiler.h

@@ -334,6 +334,9 @@ typedef struct {
        /* For creating temporaries */
        unsigned temp_alloc;
 
+       /* Analysis results */
+       bool has_liveness;
+
        /* Stats for shader-db */
        unsigned instruction_count;
        unsigned loop_count;
@@ -500,4 +503,11 @@ uint16_t bi_bytemask_of_read_components(bi_instruction *ins, unsigned node);
 
 void bi_schedule(bi_context *ctx);
 
+/* Liveness */
+
+void bi_compute_liveness(bi_context *ctx);
+void bi_liveness_ins_update(uint16_t *live, bi_instruction *ins, unsigned max);
+void bi_invalidate_liveness(bi_context *ctx);
+bool bi_is_live_after(bi_context *ctx, bi_block *block, bi_instruction *start, int src);
+
 #endif

src/panfrost/bifrost/meson.build

@@ -21,6 +21,7 @@
 
 libpanfrost_bifrost_files = files(
   'disassemble.c',
+  'bi_liveness.c',
   'bi_print.c',
   'bi_schedule.c',
   'bi_tables.c',