[PATCH] D135727: [clang] Correct sanitizer behavior in union FAMs

Bill Wendling via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Tue Oct 11 16:27:55 PDT 2022


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Clang doesn't have the same behavior as GCC does with union flexible
array members. (Technically, union FAMs are probably not acceptable in
C99 and are an extension / accidentally supported "feature" of GCC and
Clang, but I digress.)

Both Clang and GCC treat *all* arrays at the end of a structure as FAMs.
GCC does the same with unions. Clang does it for some arrays in unions
(incomplete, '0', and '1'), but for all. Instead of having this
half-supported feature, sync Clang's behavior with GCC's.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D135727

Files:
  clang/lib/AST/Expr.cpp
  clang/test/CodeGen/bounds-checking-fam.c
  clang/test/CodeGen/bounds-checking.c

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