[llvm] [RISCV][Disassembler] Use a table to store all the decoder tables and their associated features. NFC (PR #130883)

[Sam Elliott via llvm-commits]

================
@@ -620,29 +620,19 @@ void RISCVDisassembler::addSPOperands(MCInst &MI) const {
       MI.insert(MI.begin() + i, MCOperand::createReg(RISCV::X2));
 }
 
-#define TRY_TO_DECODE_WITH_ADDITIONAL_OPERATION(FEATURE_CHECKS, DECODER_TABLE, \
-                                                DESC, ADDITIONAL_OPERATION)    \
-  do {                                                                         \
-    if (FEATURE_CHECKS) {                                                      \
-      LLVM_DEBUG(dbgs() << "Trying " << DESC << " table:\n");                  \
-      DecodeStatus Result =                                                    \
-          decodeInstruction(DECODER_TABLE, MI, Insn, Address, this, STI);      \
-      if (Result != MCDisassembler::Fail) {                                    \
-        ADDITIONAL_OPERATION;                                                  \
-        return Result;                                                         \
-      }                                                                        \
-    }                                                                          \
-  } while (false)
-#define TRY_TO_DECODE_AND_ADD_SP(FEATURE_CHECKS, DECODER_TABLE, DESC)          \
-  TRY_TO_DECODE_WITH_ADDITIONAL_OPERATION(FEATURE_CHECKS, DECODER_TABLE, DESC, \
-                                          addSPOperands(MI))
-#define TRY_TO_DECODE(FEATURE_CHECKS, DECODER_TABLE, DESC)                     \
-  TRY_TO_DECODE_WITH_ADDITIONAL_OPERATION(FEATURE_CHECKS, DECODER_TABLE, DESC, \
-                                          (void)nullptr)
-#define TRY_TO_DECODE_FEATURE(FEATURE, DECODER_TABLE, DESC)                    \
-  TRY_TO_DECODE(STI.hasFeature(FEATURE), DECODER_TABLE, DESC)
-#define TRY_TO_DECODE_FEATURE_ANY(FEATURES, DECODER_TABLE, DESC)               \
-  TRY_TO_DECODE((STI.getFeatureBits() & (FEATURES)).any(), DECODER_TABLE, DESC)
+namespace {
+
+struct DecoderListEntry {
+  const uint8_t *Table;
+  FeatureBitset RequiredFeatures;
----------------
lenary wrote:

Let's give this a different name - usually when we have a bitmap with "required" in the name, it means you're comparing based on all the bits being set, whereas here we just want if any are set.

This also applies to `haveRequiredFeatures` below, which should use the same adjective that you choose instead of "required".

 

https://github.com/llvm/llvm-project/pull/130883