[clang][modules] Fix use-after-free in header serialization (#96356)

With the pruning of unused module map files disabled
(`-fno-modules-prune-non-affecting-module-map-files`), `HeaderFileInfo`
no longer gets deserialized before `ASTWriter::WriteHeaderSearch()`.
This function then interleaves the stores of references to `KnownHeader`
with their lazy deserialization. Lazy deserialization may cause
reallocation of `ModuleMap::Headers` entries (including its
`SmallVector<KnownHeader, 1>` values) thus making previously-stored
`ArrayRef<KnownHeader>` dangling. This patch fixes that situation by
storing a copy instead.

0 files changed, 0 insertions, 0 deletions