[PATCH] D103142: [clang][clangd] Use reverse header map lookup in suggestPathToFileForDiagnostics

[Bruno Cardoso Lopes via Phabricator via cfe-commits]

bruno added inline comments.


================
Comment at: clang/lib/Lex/HeaderMap.cpp:265
+  }
+  return ReverseMap.lookup(DestPath);
+}
----------------
How about something along the lines of:

```
...
StringRef Key;
for (unsigned i = 0; i != NumBuckets; ++i) {
    HMapBucket B = getBucket(i);
    if (B.Key == HMAP_EmptyBucketKey)
      continue;

    Key = getString(B.Key);
    Optional<StringRef> Prefix = getString(B.Prefix);
    Optional<StringRef> Suffix = getString(B.Suffix);
    if (!Key.empty() && Prefix && Suffix) {
      SmallVector<char, 1024> Buf;
      Buf.append(Prefix->begin(), Prefix->end());
      Buf.append(Suffix->begin(), Suffix->end());
      ReverseMap[StringRef(Buf.begin(), Buf.size())] = Key;
      break;
    }
}
assert(!Key.empty() && "expected valid key");
return Key;
```

While proposing this change I've noticed that it would keep looking for other buckets even in face of a valid result, so I've added a `break`. Was that intentional? 


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D103142/new/

https://reviews.llvm.org/D103142