pan/bi: Add quirks system

Modeled after the Midgard system. Already we know of two
compiler-visible differences between G52 and G71, so let's keep track so
we can eventually port the compiler to other Bifrost systems.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4061>

src/panfrost/Makefile.sources

@@ -3,6 +3,7 @@ bifrost_FILES := \
         bifrost/bifrost_compile.c \
         bifrost/bifrost_compile.h \
         bifrost/bifrost_tables.c \
+        bifrost/bi_quirks.c \
         bifrost/compiler.h \
         bifrost/cmdline.c \
         bifrost/disassemble.c \

src/panfrost/bifrost/bi_quirks.h

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2019-2020 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.
+ */
+
+#ifndef __BI_QUIRKS_H
+#define __BI_QUIRKS_H
+
+/* Model-specific quirks requiring compiler workarounds/etc. Quirks
+ * may be errata requiring a workaround, or features. We're trying to be
+ * quirk-positive here; quirky is the best! */
+
+/* Whether this GPU lacks support for the preload mechanism. New GPUs can have
+ * varyings and textures preloaded into the fragment shader to amortize the I/O
+ * cost; early Bifrost models lacked this feature. */
+
+#define BIFROST_NO_PRELOAD (1 << 0)
+
+/* Whether this GPU lacks support for the _FAST family of opcodes for fast
+ * computation of special functions requiring lookup tables. Early GPUs require
+ * rather unweildly lowering mechanisms for thesr things. */
+
+#define BIFROST_NO_FAST_OP (1 << 1)
+
+static inline unsigned
+bifrost_get_quirks(unsigned product_id)
+{
+        switch (product_id >> 12) {
+        case 6: /* 1st gen */
+                return BIFROST_NO_PRELOAD |
+                        BIFROST_NO_FAST_OP;
+
+        case 7: /* 2nd gen */
+        case 8: /* 3rd gen */
+                return 0;
+
+        default:
+                unreachable("Unknown Bifrost GPU ID");
+        }
+}
+
+#endif

src/panfrost/bifrost/bifrost_compile.c

@@ -33,12 +33,14 @@
 #include "disassemble.h"
 #include "bifrost_compile.h"
 #include "compiler.h"
+#include "bi_quirks.h"
 
 void
-bifrost_compile_shader_nir(nir_shader *nir, bifrost_program *program)
+bifrost_compile_shader_nir(nir_shader *nir, bifrost_program *program, unsigned product_id)
 {
         bi_context *ctx = rzalloc(NULL, bi_context);
         ctx->nir = nir;
+        ctx->quirks = bifrost_get_quirks(product_id);
 
         nir_print_shader(nir, stdout);
 

src/panfrost/bifrost/bifrost_compile.h

@@ -31,7 +31,7 @@ typedef struct {
         struct util_dynarray compiled;
 } bifrost_program;
 
-void bifrost_compile_shader_nir(nir_shader *nir, bifrost_program *program);
+void bifrost_compile_shader_nir(nir_shader *nir, bifrost_program *program, unsigned product_id);
 
 static const nir_shader_compiler_options bifrost_nir_options = {
         .lower_ffma = true,

src/panfrost/bifrost/cmdline.c

@@ -65,7 +65,9 @@ compile_shader(char **argv)
 
                 NIR_PASS_V(nir[i], gl_nir_lower_buffers, prog);
                 NIR_PASS_V(nir[i], nir_opt_constant_folding);
-                bifrost_compile_shader_nir(nir[i], &compiled);
+
+                unsigned product_id = 0x7212; /* Mali G52 */
+                bifrost_compile_shader_nir(nir[i], &compiled, product_id);
         }
 }
 

src/panfrost/bifrost/compiler.h

@@ -318,6 +318,7 @@ typedef struct bi_block {
 typedef struct {
        nir_shader *nir;
        struct list_head blocks; /* list of bi_block */
+       uint32_t quirks;
 } bi_context; 
 
 /* So we can distinguish between SSA/reg/sentinel quickly */