[lldb][windows] add sibling-import fallback to LoadImage helper (#197218)

`PlatformWindows::DoLoadImage` injects `__lldb_LoadLibraryHelper` which
registers each caller-supplied search path via `AddDllDirectory()` and
calls `LoadLibraryExW(name, nullptr, LOAD_LIBRARY_SEARCH_DEFAULT_DIRS)`.
In practice however, this flow fails for a common layout where a DLL
lives next to its sibling imports. LoadLibraryExW returns
ERROR_CANT_RESOLVE_FILENAME and the load is reported as unrecoverable,
even though every required DLL is present in one of the search paths.

This patch adds a fallback after the first `LoadLibraryExW(name,
nullptr, LOAD_LIBRARY_SEARCH_DEFAULT_DIRS)` call: if it fails, iterate
the caller-provided search paths and try `LoadLibraryExW(path, nullptr,
LOAD_WITH_ALTERED_SEARCH_PATH)`. `LOAD_WITH_ALTERED_SEARCH_PATH`
instructs the Windows loader to add the DLL's own directory to the
dependency search.

See
https://learn.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryexa.

---------

Co-authored-by: Nerixyz <nero.9@hotmail.de>
1 file changed
tree: 2d3f7fd94cd29d975f3828961f053581a9b98b47
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. flang-rt/
  11. libc/
  12. libclc/
  13. libcxx/
  14. libcxxabi/
  15. libsycl/
  16. libunwind/
  17. lld/
  18. lldb/
  19. llvm/
  20. llvm-libgcc/
  21. mlir/
  22. offload/
  23. openmp/
  24. orc-rt/
  25. polly/
  26. runtimes/
  27. third-party/
  28. utils/
  29. .clang-format
  30. .clang-format-ignore
  31. .clang-tidy
  32. .git-blame-ignore-revs
  33. .gitattributes
  34. .gitignore
  35. .mailmap
  36. CODE_OF_CONDUCT.md
  37. CONTRIBUTING.md
  38. LICENSE.TXT
  39. pyproject.toml
  40. README.md
  41. SECURITY.md
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