[Support][Windows] disk_space handle unicode paths (#170716)

replaces GetDiskFreeSpaceExA with GetDiskFreeSpaceExW to handle user
paths with Unicode characters

fixes: #170571

I’m not entirely sure the fix is correct, so I’d appreciate it if
someone more familiar with the code could review it. Thanks!

Author: ahorek

llvm/lib/Support/CachePruning.cpp

@@ -280,7 +280,9 @@ bool llvm::pruneCache(StringRef Path, CachePruningPolicy Policy,
   if (Policy.MaxSizePercentageOfAvailableSpace > 0 || Policy.MaxSizeBytes > 0) {
     auto ErrOrSpaceInfo = sys::fs::disk_space(Path);
     if (!ErrOrSpaceInfo) {
-      report_fatal_error("Can't get available size");
+      auto EC = ErrOrSpaceInfo.getError();
+      report_fatal_error(Twine("Can't get available size for '") + Path.str() +
+                         "': " + EC.message());
     }
     sys::fs::space_info SpaceInfo = ErrOrSpaceInfo.get();
     auto AvailableSpace = TotalSize + SpaceInfo.free;

llvm/lib/Support/Windows/Path.inc

@@ -170,14 +170,19 @@ UniqueID file_status::getUniqueID() const {
 
 ErrorOr<space_info> disk_space(const Twine &Path) {
   ULARGE_INTEGER Avail, Total, Free;
-  if (!::GetDiskFreeSpaceExA(Path.str().c_str(), &Avail, &Total, &Free))
+  SmallVector<wchar_t, 128> PathUTF16;
+
+  if (std::error_code EC = widenPath(Path, PathUTF16))
+    return EC;
+
+  if (!::GetDiskFreeSpaceExW(PathUTF16.data(), &Avail, &Total, &Free))
     return mapWindowsError(::GetLastError());
+
   space_info SpaceInfo;
-  SpaceInfo.capacity =
-      (static_cast<uint64_t>(Total.HighPart) << 32) + Total.LowPart;
-  SpaceInfo.free = (static_cast<uint64_t>(Free.HighPart) << 32) + Free.LowPart;
-  SpaceInfo.available =
-      (static_cast<uint64_t>(Avail.HighPart) << 32) + Avail.LowPart;
+  SpaceInfo.capacity = Total.QuadPart;
+  SpaceInfo.free = Free.QuadPart;
+  SpaceInfo.available = Avail.QuadPart;
+
   return SpaceInfo;
 }