Index: llvm/lib/Support/Windows/Path.inc =================================================================== --- llvm/lib/Support/Windows/Path.inc +++ llvm/lib/Support/Windows/Path.inc @@ -371,13 +371,19 @@ if (std::error_code EC = realPathFromHandle(H, Buffer)) return EC; - const wchar_t *Data = Buffer.data(); + // Strip the \\?\ prefix. We don't want it ending up in output, and such + // paths don't get canonicalized by file APIs. + wchar_t *Data = Buffer.data(); DWORD CountChars = Buffer.size(); - if (CountChars >= 4) { - if (0 == ::memcmp(Data, L"\\\\?\\", 8)) { - CountChars -= 4; - Data += 4; - } + if (CountChars >= 8 && ::memcmp(Data, L"\\\\?\\UNC\\", 16) == 0) { + // Convert \\?\UNC\foo\bar to \\foo\bar + CountChars -= 6; + Data += 6; + Data[0] = '\\'; + } else if (CountChars >= 4 && ::memcmp(Data, L"\\\\?\\", 8) == 0) { + // Convert \\?\c:\foo to c:\foo + CountChars -= 4; + Data += 4; } // Convert the result from UTF-16 to UTF-8.