[llvm] [Tablegen] Add keywork `dump`. (PR #68793)

[Francesco Petrogalli via llvm-commits]

================
@@ -4359,3 +4390,27 @@ LLVM_DUMP_METHOD void MultiClass::dump() const {
     E.dump();
 }
 #endif
+
+bool TGParser::ParseDump(MultiClass *CurMultiClass, Record *CurRec) {
+  assert(Lex.getCode() == tgtok::Dump && "Unknown tok");
+  Lex.Lex(); // eat the operation
+
+  Init *Message = ParseValue(CurRec);
+  if (!Message)
+    return true;
+
+  std::string Msg;
+  if (auto SI = dyn_cast<StringInit>(Message))
+    Msg = SI->getValue();
+
+  if (!consume(tgtok::semi))
+    return TokError("expected ';'");
+
+  SMLoc ConditionLoc = Lex.getLoc();
+  if (CurRec)
+    CurRec->addDump(ConditionLoc, Message);
+  else
+    addEntry(std::make_unique<Record::DumpInfo>(ConditionLoc, Message));
----------------
fpetrogalli wrote:

```suggestion
  SMLoc Loc = Lex.getLoc();
  if (CurRec)
    CurRec->addDump(Loc, Message);
  else
    addEntry(std::make_unique<Record::DumpInfo>(Loc, Message));
```

https://github.com/llvm/llvm-project/pull/68793