[lld] [lld][macho] Support order cstrings with -order_file_cstring (PR #140307)

[Ellis Hoag via llvm-commits]

================
@@ -330,10 +334,19 @@ void macho::PriorityBuilder::parseOrderFile(StringRef path) {
         break;
       }
     }
-    symbol = line.trim();
 
-    if (!symbol.empty()) {
-      SymbolPriorityEntry &entry = priorities[symbol];
+    // The rest of the line is either <symbol name> or
+    // CStringEntryPrefix<cstring hash>
+    if (line.starts_with(CStringEntryPrefix)) {
+      StringRef possibleHash = line.drop_front(CStringEntryPrefix.size());
+      uint32_t hash = 0;
+      if (to_integer(possibleHash, hash))
+        line = possibleHash;
+    }
+    symbolOrCStrHash = line.trim();
+
+    if (!symbolOrCStrHash.empty()) {
+      SymbolPriorityEntry &entry = priorities[symbolOrCStrHash];
----------------
ellishg wrote:

I think this is a good place to report an error if the orderfile cannot be parsed. It might take some refactoring to avoid code duplication

```suggestion
    // The rest of the line is either <symbol name> or
    // CStringEntryPrefix<cstring hash>
    if (line.consume_front(CStringEntryPrefix)) {
      uint32_t hash;
      if (!line.consume_integer(/*Radix=*/0, hash))
        // report error
      if (!line.trim().empty())
        // report error
      SymbolPriorityEntry &entry = cstrPriorities[hash];
      // assign priority and return?
    }
    symbol = line.trim();

    if (!symbol.empty()) {
      SymbolPriorityEntry &entry = priorities[symbol];
```

https://github.com/llvm/llvm-project/pull/140307