intel/eu: Rework opcode description tables to allow efficient look-up by either HW or IR opcode.

This rewrites the current opcode description tables as a more compact
flat data structure.  The purpose is to allow efficient constant-time
look-up by either HW or IR opcode, which will allow us to drop the
hard-coded correspondence between HW and IR opcodes -- See the next
commits for the rationale.

brw_eu.c is now built as C++ source so we can take advantage of
pointers to member in order to make the look-up function work
regardless of the opcode_desc member used as look-up key.

v2: Optimize devinfo struct comparison (Caio)

Reviewed-by: Caio Marcelo de Oliveira Filho <[email protected]>
Reviewed-by: Jordan Justen <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 22 insertions, 21 deletions

diff --git a/src/intel/compiler/brw_eu.h b/src/intel/compiler/brw_eu.h
index ef2cf889cd1..282ebd7d563 100644
--- a/src/intel/compiler/brw_eu.h
+++ b/src/intel/compiler/brw_eu.h
@@ -1221,32 +1221,33 @@ next_offset(const struct gen_device_info *devinfo, void *store, int offset)
 }
 
 struct opcode_desc {
-   /* The union is an implementation detail used by brw_opcode_desc() to handle
-    * opcodes that have been reused for different instructions across hardware
-    * generations.
-    *
-    * The gens field acts as a tag. If it is non-zero, name points to a string
-    * containing the instruction mnemonic. If it is zero, the table field is
-    * valid and either points to a secondary opcode_desc table with 'size'
-    * elements or is NULL and no such instruction exists for the opcode.
-    */
-   union {
-      struct {
-         char    *name;
-         int      nsrc;
-      };
-      struct {
-         const struct opcode_desc *table;
-         unsigned size;
-      };
-   };
-   int      ndst;
-   int      gens;
+   unsigned ir;
+   unsigned hw;
+   const char *name;
+   int nsrc;
+   int ndst;
+   int gens;
 };
 
 const struct opcode_desc *
 brw_opcode_desc(const struct gen_device_info *devinfo, enum opcode opcode);
 
+const struct opcode_desc *
+brw_opcode_desc_from_hw(const struct gen_device_info *devinfo, unsigned hw);
+
+static inline unsigned
+brw_opcode_encode(const struct gen_device_info *devinfo, enum opcode opcode)
+{
+   return brw_opcode_desc(devinfo, opcode)->hw;
+}
+
+static inline enum opcode
+brw_opcode_decode(const struct gen_device_info *devinfo, unsigned hw)
+{
+   const struct opcode_desc *desc = brw_opcode_desc_from_hw(devinfo, hw);
+   return desc ? (enum opcode)desc->ir : BRW_OPCODE_ILLEGAL;
+}
+
 static inline bool
 is_3src(const struct gen_device_info *devinfo, enum opcode opcode)
 {