[LifetimeSafety] Model bit_cast and atomic casts in the fact generator (#204591)
VisitCastExpr dropped several borrow-carrying cast kinds into its
default case. Propagate the borrow through
`__builtin_bit_cast`/`std::bit_cast` of a pointer and through
wrapping/unwrapping `_Atomic(T*)`, so a stack address laundered through
either is caught (matching reinterpret_cast). hasOrigins and
buildListForType now see through AtomicType, which is transparent for
lifetimes.
Assisted-by: Claude Opus 4.8
Co-authored-by: Gabor Horvath <gaborh at apple.com>
[ELF][AArch64] Relax zero TLSLE add to nop (#204286)
Optimize AArch64 local-exec TLS relocation handling by replacing a
self-add R_AARCH64_TLSLE_ADD_TPREL_HI12 instruction with nop when the
high 12 bits are zero.
The optimization is disabled by --no-relax and avoids non-equivalent
forms such as non-self-adds and 32-bit destination registers.
[lit] Make RecursionError less likely in internal shell (#204573)
The lit internal shell chains together the contents of multiple RUN:
lines by connecting them with implicit && nodes, forming a binary tree
structure which is then executed recursively by `_executeShCommand`.
However the tree structure is constructed in a very simple way which
makes it effectively just a linked list, so `_executeShCommand` must
recurse to a depth equal to the number of commands.
If a test file contains more than 1000 RUN: lines (e.g. running the
clang driver only, with lots of different options), then this causes a
RecursionError exception, which did not happen using the external shell.
Failures of this kind can be avoided by instead connecting the commands
together in a _balanced_ binary tree, which has equivalent behaviour,
since the && shell operator is associative.
