disas/riscv: Encapsulate opcode_data into decode

This patch adds a reference to a struct rv_opcode_data object
into struct rv_decode. This further allows to remove all references
to the global variable opcode_data (which is renamed to rvi_opcode_data).

This patch does not introduce any functional change, but prepares
the code for more struct rv_opcode_data objects in the future.

This patch is based on previous work from Liu Zhiwei:
  https://lists.nongnu.org/archive/html/qemu-devel/2022-08/msg03662.html

Co-developed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Message-Id: <20230612111034.3955227-6-christoph.muellner@vrull.eu>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

disas/riscv.c

@@ -1068,7 +1068,7 @@ static const rv_comp_data rvcp_fsgnjx_q[] = {
 
 /* instruction metadata */
 
-const rv_opcode_data opcode_data[] = {
+const rv_opcode_data rvi_opcode_data[] = {
     { "illegal", rv_codec_illegal, rv_fmt_none, NULL, 0, 0, 0 },
     { "lui", rv_codec_u, rv_fmt_rd_imm, NULL, 0, 0, 0 },
     { "auipc", rv_codec_u, rv_fmt_rd_offset, NULL, 0, 0, 0 },
@@ -3889,6 +3889,7 @@ static uint32_t operand_tbl_index(rv_inst inst)
 
 static void decode_inst_operands(rv_decode *dec, rv_isa isa)
 {
+    const rv_opcode_data *opcode_data = dec->opcode_data;
     rv_inst inst = dec->inst;
     dec->codec = opcode_data[dec->op].codec;
     switch (dec->codec) {
@@ -4371,6 +4372,7 @@ static void append(char *s1, const char *s2, size_t n)
 
 static void format_inst(char *buf, size_t buflen, size_t tab, rv_decode *dec)
 {
+    const rv_opcode_data *opcode_data = dec->opcode_data;
     char tmp[64];
     const char *fmt;
 
@@ -4612,6 +4614,7 @@ static void format_inst(char *buf, size_t buflen, size_t tab, rv_decode *dec)
 
 static void decode_inst_lift_pseudo(rv_decode *dec)
 {
+    const rv_opcode_data *opcode_data = dec->opcode_data;
     const rv_comp_data *comp_data = opcode_data[dec->op].pseudo;
     if (!comp_data) {
         return;
@@ -4630,6 +4633,7 @@ static void decode_inst_lift_pseudo(rv_decode *dec)
 
 static void decode_inst_decompress_rv32(rv_decode *dec)
 {
+    const rv_opcode_data *opcode_data = dec->opcode_data;
     int decomp_op = opcode_data[dec->op].decomp_rv32;
     if (decomp_op != rv_op_illegal) {
         if ((opcode_data[dec->op].decomp_data & rvcd_imm_nz)
@@ -4644,6 +4648,7 @@ static void decode_inst_decompress_rv32(rv_decode *dec)
 
 static void decode_inst_decompress_rv64(rv_decode *dec)
 {
+    const rv_opcode_data *opcode_data = dec->opcode_data;
     int decomp_op = opcode_data[dec->op].decomp_rv64;
     if (decomp_op != rv_op_illegal) {
         if ((opcode_data[dec->op].decomp_data & rvcd_imm_nz)
@@ -4658,6 +4663,7 @@ static void decode_inst_decompress_rv64(rv_decode *dec)
 
 static void decode_inst_decompress_rv128(rv_decode *dec)
 {
+    const rv_opcode_data *opcode_data = dec->opcode_data;
     int decomp_op = opcode_data[dec->op].decomp_rv128;
     if (decomp_op != rv_op_illegal) {
         if ((opcode_data[dec->op].decomp_data & rvcd_imm_nz)
@@ -4694,6 +4700,7 @@ disasm_inst(char *buf, size_t buflen, rv_isa isa, uint64_t pc, rv_inst inst,
     rv_decode dec = { 0 };
     dec.pc = pc;
     dec.inst = inst;
+    dec.opcode_data = rvi_opcode_data;
     dec.cfg = cfg;
     decode_inst_opcode(&dec, isa);
     decode_inst_operands(&dec, isa);

disas/riscv.h

@@ -163,10 +163,27 @@ typedef enum {
 
 /* structures */
 
+typedef struct {
+    const int op;
+    const rvc_constraint *constraints;
+} rv_comp_data;
+
+typedef struct {
+    const char * const name;
+    const rv_codec codec;
+    const char * const format;
+    const rv_comp_data *pseudo;
+    const short decomp_rv32;
+    const short decomp_rv64;
+    const short decomp_rv128;
+    const short decomp_data;
+} rv_opcode_data;
+
 typedef struct {
     RISCVCPUConfig *cfg;
     uint64_t  pc;
     uint64_t  inst;
+    const rv_opcode_data *opcode_data;
     int32_t   imm;
     uint16_t  op;
     uint8_t   codec;
@@ -186,11 +203,6 @@ typedef struct {
     uint8_t   rlist;
 } rv_decode;
 
-typedef struct {
-    const int op;
-    const rvc_constraint *constraints;
-} rv_comp_data;
-
 enum {
     rv_op_illegal = 0
 };
@@ -199,17 +211,6 @@ enum {
     rvcd_imm_nz = 0x1
 };
 
-typedef struct {
-    const char * const name;
-    const rv_codec codec;
-    const char * const format;
-    const rv_comp_data *pseudo;
-    const short decomp_rv32;
-    const short decomp_rv64;
-    const short decomp_rv128;
-    const short decomp_data;
-} rv_opcode_data;
-
 /* instruction formats */
 
 #define rv_fmt_none                   "O\t"