[qt/clang/llvm-project]: Summary of bulk changes made

Git repository change summary for qt/clang/llvm-project
Pushed by mirror-service into branch 'upstream/users/schrodingerzhu/libc-use-tlsf-freestore'.
Changed from b4a77f5fc7c5123ee9966595dcffc48481e30592 to e1871dcedc18738f23433422410dc360cef1f8d9
Acknowledgement was received that this change introduces only existing code that has been pushed to another public open source repository.

This change contains the following new commits:

Git commit e1871dcedc18738f23433422410dc360cef1f8d9 by Yifan Zhu on 31/07/2026 at 20:37..
[libc][__support] Implement exact linear binning for TLSFFreeStoreImpl

Previously, size_to_bit_index used size >> UNIT_SIZE_LOG2 for linear bins,
which mapped size 24 to bin 1 and size 17 to bin 1, causing a mismatch
between allocation request sizes and physical block bucket sizes.

This change introduces exact mapping for linear bins:
- Introduces LINEAR_BINS to compute the exact number of linear bins needed
  to reach the exponential table boundary (29 on MSVC Windows where UNIT_SIZE is 8,
  31 on Linux where UNIT_SIZE is 16).
- Sizes <= MIN_INNER_SIZE map to bin 0.
- Larger linear sizes map to ((size - MIN_INNER_SIZE - 1) >> UNIT_SIZE_LOG2) + 1.
- Uses LINEAR_BINS as the base index for exponential bins in size_to_bit_index,
  index_to_min_size, and find_and_remove_fit, ensuring strict monotonicity
  across all indices without runtime clamping.
- Adds NegativeTestForFullHeap unit test in freelist_heap_test.cpp and updates
  freestore_test.cpp.

TAG=agy
CONV=cff84e8c-ee22-4f39-af3c-344d1e6f417b
https://invent.kde.org/qt/clang/llvm-project/-/commit/e1871dcedc18738f23433422410dc360cef1f8d9