pan/bit: Stub out BIR interpreter

We'd like to step through a BIR program to evaluate it for testing.
Let's stub out some infrastructure for modeling Bifrost.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4458>

src/panfrost/bifrost/test/bi_interpret.c

@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2020 Collabora Ltd.
+ *
+ * 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.
+ *
+ * Authors (Collabora):
+ *      Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
+ */
+
+#include "bit.h"
+
+typedef union {
+        uint64_t u64;
+        uint32_t u32;
+        uint16_t u16[2];
+        uint8_t u8[4];
+        double f64;
+        float f32;
+        uint16_t f16;
+} bit_t;
+
+/* Interprets a subset of Bifrost IR required for automated testing */
+
+static uint64_t
+bit_read(struct bit_state *s, bi_instruction *ins, unsigned index, nir_alu_type T)
+{
+        /* STUB */
+        return 0;
+}
+
+static void
+bit_write(struct bit_state *s, unsigned index, nir_alu_type T, bit_t value)
+{
+        /* STUB */
+}
+
+void
+bit_step(struct bit_state *s, bi_instruction *ins)
+{
+        /* First, load sources */
+        bit_t srcs[BIR_SRC_COUNT] = { 0 };
+
+        bi_foreach_src(ins, src)
+                srcs[src].u64 = bit_read(s, ins, ins->src[src], ins->src_types[src]);
+
+        /* Next, do the action of the instruction */
+        bit_t dest = { 0 };
+
+        switch (ins->type) {
+        case BI_ADD:
+        case BI_ATEST:
+        case BI_BRANCH:
+        case BI_CMP:
+        case BI_BLEND:
+        case BI_BITWISE:
+        case BI_COMBINE:
+        case BI_CONVERT:
+        case BI_CSEL:
+        case BI_DISCARD:
+        case BI_FMA:
+        case BI_FREXP:
+        case BI_ISUB:
+        case BI_LOAD:
+        case BI_LOAD_UNIFORM:
+        case BI_LOAD_ATTR:
+        case BI_LOAD_VAR:
+        case BI_LOAD_VAR_ADDRESS:
+        case BI_MINMAX:
+        case BI_MOV:
+        case BI_SHIFT:
+        case BI_STORE:
+        case BI_STORE_VAR:
+        case BI_SPECIAL: /* _FAST, _TABLE on supported GPUs */
+        case BI_SWIZZLE:
+        case BI_TEX:
+        case BI_ROUND:
+        default:
+                unreachable("Unsupported op");
+        }
+
+        /* Finally, store the result */
+        bit_write(s, ins->dest, ins->dest_type, dest);
+}

src/panfrost/bifrost/test/bit.h

@@ -31,6 +31,7 @@
 #include "panfrost/encoder/pan_device.h"
 #include "panfrost/encoder/pan_bo.h"
 #include "bifrost_compile.h"
+#include "bifrost/compiler.h"
 
 struct panfrost_device *
 bit_initialize(void *memctx);
@@ -49,6 +50,15 @@ bit_vertex(struct panfrost_device *dev, panfrost_program prog,
                 uint32_t *iattr, size_t sz_attr,
                 uint32_t *expected, size_t sz_expected, enum bit_debug);
 
+/* BIT interpreter */
+
+struct bit_state {
+        uint32_t r[64];
+};
+
+void
+bit_step(struct bit_state *s, bi_instruction *ins);
+
 #endif
 
 

src/panfrost/meson.build

@@ -36,7 +36,8 @@ subdir('encoder')
 
 files_bifrost = files(
   'bifrost/cmdline.c',
-  'bifrost/test/bi_submit.c'
+  'bifrost/test/bi_submit.c',
+  'bifrost/test/bi_interpret.c',
 )
 
 bifrost_compiler = executable(