[compiler-rt] [win/asan] Improve SharedReAlloc with HEAP_REALLOC_IN_PLACE_ONLY. (PR #132558)

[Thurston Dang via llvm-commits]

thurstond wrote:

Would this approach in general make bug detection worse? The existing behavior of realloc always returning a new pointer (with the old memory marked inaccessible) can catch erroneous code that assumes the realloc is in place (or worse, inconsistently uses both the old pointer and the return value of realloc).

> Currently it prints only a "use-after-poison" message, not a proper "heap-buffer-overflow" with a hint to a reallocation.

This will be confusing to users and could lead them on a wild good chase, looking for bugs in poisoning.


https://github.com/llvm/llvm-project/pull/132558